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300 | List the off-label use of SSRIs | depression during childhood and adolescence
Premature ejaculation (PE)
erectile dysfunction
Insomnia
postprostatectomy established stress urinary incontinence.
mood and anxiety disorders during pregnancy and breast feeding
symptoms of vasomotor dysregulation (hot flashes) associated with the menopausal transition and sex hormone deprivation
..off-label uses include the treatment of bulimia, benzodiazepine/alcohol dependence, fibromyalgia, central nervous system degenerative diseases (behavioral disorders in dementia and other organic disorders), schizophrenia, chronic pain disease and diabetic neuropathy, sexual dysfunction. | [15928960, 23093633, 15291651, 22760463, 22136212, 20235039, 22473248, 18330528, 22712761, 18360636, 15062207, 16481094, 23425613, 15643101, 21077473, 18371047, 16310120, 21601255, 21176430] | 407 | The landscape has dramatically changed for patients seeking treatment for rapid ejaculation. Previously, psychotherapy or behavioral treatment was considered to be the treatment of choice for this troubling sexual dysfunction. Since the early 1990s, an efficacious alternative treatment has emerged-the off-label administration of SSRI medications. Currently, several short-acting SSRI compounds are in phase III clinical trials and are likely to receive approval as the first medical treatment for rapid ejaculation. Given the presumed efficacy of these new compounds and the off-label use of the current SSRIs, one might conclude that psychotherapy\behavior therapy for rapid ejaculation is an obsolete and antiquated intervention. On the contrary, psychotherapy is now more relevant than ever. The two aims of this paper are to review psychological/behavioral therapies for rapid ejaculation and to discuss the important role of combined psychological and medical treatment. In the new age of SSRI treatment for rapid ejaculation, some form of psychological/behavioral intervention is essential to help patients/couples make better use of medical therapies, to learn skills to delay ejaculation once off medication, to bolster sexual confidence, and to enhance patient and partner sexual satisfaction. Premature ejaculation (PE) is a common sexual dysfunction affecting 20% to 30% of men worldwide. Definitions of PE vary, but it is typically characterized by short intravaginal ejaculatory latency time (IELT) with concomitant sexual dissatisfaction and distress. PE may be lifelong or acquired, but its etiology remains unclear. Treatment of PE typically involves pharmacotherapy, particularly when lifelong. Although there are numerous reports on the off-label use of selective serotonin reuptake inhibitors (SSRIs) and other compounds, only 2 treatments have been evaluated in randomized controlled phase 3 clinical trials: PSD502 and dapoxetine (SSRI). Both significantly improved IELT and patient-reported outcome domains of ejaculatory control, sexual satisfaction, and distress as measured by the index of premature ejaculation (IPE), compared with placebo. They constitute the focus of this review. Evidence demonstrated that PSD502, dapoxetine and other SSRIs all significantly improve the symptoms of PE. Systemic use of SSRIs presents risks associated with the known pharmacology of this class. PSD502 allows for topical on-demand treatment applied applied immediately before intercourse, and is not associated with systemic adverse events. BACKGROUND: The last few years have seen a remarkable rise in the off-label use of trazodone for inducing sleep in nondepressed patients, to a degree that it is prescribed for this purpose as commonly as the leading hypnotic. In view of this widespread popularity, it seems prudent to review what is known of the safety and efficacy of trazodone when used in this context. DATA SOURCES AND SELECTION: A MEDLINE search of the literature published in English between 1975 and 2003 that included the keywords sleep, trazodone, Desyrel, depression, sleeping pill, and sedative-hypnotics was conducted. DATA SYNTHESIS: From this review, it is concluded that there are very few data to suggest that trazodone improves sleep in patients without mood disorder, though it does increase total sleep in patients with major depressive disorder. There are virtually no dose-response data for trazodone vis-à-vis sleep and, similarly, no available data on tolerance to its possible hypnotic effects. Areas of concern with its use include reports of significant dropout rates and induction of arrhythmias, primarily in patients with histories of cardiac disease, as well as the development of priapism. CONCLUSION: In summary, there are few data to support the use of trazodone in nondepressed subjects. When the risk-benefit ratio of trazodone is assessed, its side effect profile, which is much more significant than that of conventional hypnotics, should be considered. BACKGROUND: The scheduled update to the German S3 guidelines on fibromyalgia syndrome (FMS) by the Association of the Scientific Medical Societies ("Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften", AWMF; registration number 041/004) was planned starting in March 2011. MATERIALS AND METHODS: The development of the guidelines was coordinated by the German Interdisciplinary Association for Pain Therapy ("Deutsche Interdisziplinären Vereinigung für Schmerztherapie", DIVS), 9 scientific medical societies and 2 patient self-help organizations. Eight working groups with a total of 50 members were evenly balanced in terms of gender, medical field, potential conflicts of interest and hierarchical position in the medical and scientific fields. Literature searches were performed using the Medline, PsycInfo, Scopus and Cochrane Library databases (until December 2010). The grading of the strength of the evidence followed the scheme of the Oxford Centre for Evidence-Based Medicine. The recommendations were based on level of evidence, efficacy (meta-analysis of the outcomes pain, sleep, fatigue and health-related quality of life), acceptability (total dropout rate), risks (adverse events) and applicability of treatment modalities in the German health care system. The formulation and grading of recommendations was accomplished using a multi-step, formal consensus process. The guidelines were reviewed by the boards of the participating scientific medical societies. RESULTS AND CONCLUSION: Amitriptyline and-in case of comorbid depressive disorder or generalized anxiety disorder-duloxetine are recommended. Off-label use of duloxetine and pregabalin can be considered in case of no comorbid mental disorder. Strong opioids are not recommended. The English full-text version of this article is available at SpringerLink (under "Supplemental"). Phosphodiasterase type 5 inhibitors (sildenafil, vardenafil, tadalafil) are the first line symptomatic therapy for patients with erectile dysfunction. The patient should receive a meticolous information on the use of these drugs and their possible side effects. These drugs are safe and can be used even in patients with stable cardiovascular disease. Patients not responding to oral drugs may be offered intraurethral or intracavernous alprostadil. Vacuum constriction devices are a second line option more acceptable to older patients. Penile prosthesis are very seldom used in Switzerland and vascular surgery is a vanishing option. Testosterone substitution is seldom needed in this setting. Treatment of premature ejaculation subdivides into behavioural therapy ("stop-start" or "squeeze" technique) and drug therapy as well. Topical therapy with lidocaine/prilocaine-containing medications to be applied before sexual intercourse and a oral daily off label use therapy with selective serotonin re-uptake inhibitors (paroxetine, fluoxetine, sertraline) can be offered. Dapoxetine, a potent selective serotonin reuptake inhibitor with short half life time, is the first officially approved medication for the treatment of premature ejaculation and should be available soon in Switzerland. OBJECTIVE: Estrogen supplementation is considered a reliable therapeutic approach to symptoms of vasomotor dysregulation (hot flashes) associated with the menopausal transition and sex hormone deprivation. Implication of changes in central neurotransmission in the pathogenesis of hot flashes has prompted the off-label use of serotonergic and γ-aminobutyric acid-ergic drugs as a therapeutic alternative, claiming similarity of outcomes to those of estrogen treatment. METHODS: Using telemetric recordings in a rat model of estrogen deficit-induced vasomotor dysregulation, we compared the long- and short-term effects of estrogen supplementation and treatment with neuropharmaceuticals (venlafaxine, desvenlafaxine, fluoxetine, agomelatine, gabapentin) on endpoints of thermoregulation. RESULTS: Among the tested drugs, only fluoxetine was capable to emulate the restorative action of estradiol on the diurnal oscillations in skin temperature and control of heat dissipation. Unlike estradiol, several of the tested compounds produced marked transient decreases in skin temperature within the first 2 hours of application while being unable to restore physiological diurnal patterns of thermoregulation. CONCLUSIONS: Our findings suggest that in this animal model of impaired thermoregulation, neuropharmaceuticals may simulate therapeutic effects by eliciting immediate but transient hypothermia, which is not associated with the recovery of physiological control of heat dissipation. Therefore, short-term monitoring of drug actions in this disease model may considerably bias readouts of drug discovery for menopausal vasomotor symptoms. INTRODUCTION: Trazodone is an antidepressant belonging to the class of serotonin receptor antagonists and reuptake inhibitors. It is approved by the FDA for the treatment of depression. Insomnia is the most frequent reason for prescription of trazodone. It has also been proven useful in the treatment of anxiety disorders. Other off-label uses include the treatment of bulimia, benzodiazepine/alcohol dependence, fibromyalgia, central nervous system degenerative diseases (behavioral disorders in dementia and other organic disorders), schizophrenia, chronic pain disease and diabetic neuropathy, sexual dysfunction. AREAS COVERED: This paper evaluates trazodone's efficacy and safety in its off-label uses. It also discusses the possibility that a combination of trazodone with SSRIs may prevent or treat some of the SSRI side effects, such as anxiety, insomnia and sexual dysfunction, in addition to synergically increasing SSRIs' antidepressant activity. EXPERT OPINION: Few clinical trials have been conducted to evaluate trazodone's efficacy in the treatment of the diseases and symptoms for which it is often used in clinical practice. More studies are necessary to investigate possible new therapeutic indications, and to scientifically demonstrate the risk/benefit ratio for the many conditions for which trazodone is used, but not approved by the FDA. Premature ejaculation (PE) is the most common male sexual disorder, estimated to affect up to 30% of men. Over the past one or two decades, clinical investigators have participated in an increasing number of studies that are helping in our understanding of PE, which will undoubtedly facilitate future treatments. Apart from a number of behavioral approaches, the treatment of PE consists of primarily off-label use of oral selective serotonin reuptake inhibitors (SSRIs) via either on-demand or daily delivery. However, various undesirable side-effects of these medications have led researchers to search for and develop new therapeutic approaches for PE. Dapoxetine is a short-acting SSRI developed specifically for the treatment of PE. Early trials with dapoxetine have documented successful outcomes without serious short- or long-term side-effects. This review addresses the definition, classification, diagnosis, physiology, and neurobiopathology of PE, and evaluates therapeutic strategies with novel treatments for PE. Mood and anxiety disorders are common in women during their childbearing years. The prevalence of depression has been reported to be between 10% and 16% during pregnancy. The use of selective serotonin reuptake inhibitors during pregnancy or lactation is, to date, not promoted because of lack of safety documentation. However, the off-label use of these drugs has been common for several years. In the treatment of mood and anxiety disorders during pregnancy, the serotonin reuptake inhibitors are often preferred over tricyclic antidepressants because of their relatively few adverse effects and safety in overdose. This has created concern among women planning pregnancies and pregnant women, as well as among their families and physicians. Several studies and reports of the use of serotonin reuptake inhibitors during both pregnancy and lactation have been published and advanced our knowledge. We here review and discuss those studies which have been published so far on this subject. INTRODUCTION: The manufacturer of dapoxetine funded randomized clinical trials to study its effect in premature ejaculation (PE). Financial support by pharmaceutical companies, however, may jeopardize the neutrality of clinical research. AIM: To investigate the scientific process that has been followed in dapoxetine treatment trials and reviews as compared to daily drug treatment trials and reviews with selective serotonin reuptake inhibitors (SSRIs) in men with PE. METHODS: A search of Medline and Embase was conducted using the search terms "dapoxetine" or "SSRI." References of retrieved articles were searched. Only studies describing the use of these drugs in men with PE were included. Main Outcome Measures. Compared fold-increase intravaginal ejaculation latency time (IELT), geometric mean IELT, and adverse effect profiles between dapoxetine and SSRIs in PE. RESULTS: Preclinical studies on dapoxetine, including a multicenter study (category A) and reviews (category B), were compared with clinical studies with daily conventional SSRIs in PE (category C). Categories A/B focused on patient-reported outcomes with less attention for the IELT. The ejaculation-delaying effect of dapoxetine was expressed as natural mean IELT rather than as geometrical mean IELT. Dapoxetine side effects were monthly scored. In contrast, a significant part of category C articles focused on IELT data, used geometric mean IELT outcomes, and one study reported the side effects measured 24-48 hours after drug intake using a validated questionnaire. Without the Food and Drug Administration approval, dapoxetine, as well as other SSRIs in PE, is an off-label drug for PE. However, the off-label use of dapoxetine has never been criticized by clinical investigators in contrast to commentaries against the off-label use of daily SSRI treatment in PE. CONCLUSIONS: Manufacturer-funded drug treatment research (categories A and B) is advantageously treated by some authors as compared with nonfunded trials with daily conventional SSRIs (category C). PE drug treatment research is a young and dynamic field, and its development deserves transparency to its development. PURPOSE: Depression affects approximately 2-8% of all children and adolescents, and treatment of depression in children and adolescents has been the center of recent serious debates. We examined national trends in depression visits and treatment among outpatients aged 7 to 17 years. METHODS: We analyzed visit-based data between 1995 and 2002 in two national ambulatory care surveys. RESULTS: The number of visits by children and adolescents during which depression was reported more than doubled from 1995-1996 (1.44 million) to 2001-2002 (3.22 million). The proportion of these visits during which antidepressants were prescribed rose slightly from 47% in 1995-1996 to 52% in 2001-2002, whereas the proportion during which psychotherapy or mental health counseling was provided declined from 83% to 68%. Selective serotonin reuptake inhibitors (SSRI) represented 76% of all antidepressants prescribed in 1995-1996 and 81% in 2001-2002. In absolute terms, SSRIs were reported in 1.35 million visits in 2001-2002, reflecting a 2.6-fold increase from 1995-1996. Fluoxetine was prescribed in 207,914 visits in 1995-1996 and increased 100% to 415,580 visits in 2001-2002. The use of sertraline increased by 62% to 345,576 visits and paroxetine by 269% to 279,275 visits. CONCLUSIONS: We observed a declining trend in the provision of psychotherapy/mental health counseling during outpatient visits by children and adolescents diagnosed with depression. Although the likelihood of receiving antidepressants remained essentially unchanged, the number of children and adolescents whose visits involved prescription of antidepressants, particularly SSRIs, has increased markedly through 2002. Although fluoxetine remained the most commonly prescribed, other SSRIs were increasingly prescribed through 2002. These trends raise concerns regarding the widespread off-label use of antidepressants lacking reliable evidence of safety and efficacy for use in children and adolescents. Fibromyalgia (FM) is a common syndrome characterised by widespread pain and at least 11/18 painful tender points that requires multimodal pharmacological treatment also combined with non-pharmacological therapy. Various drugs currently are available to control the complex and different symptoms reported by patients. Only three drugs (duloxetine, milnacipram, pregabalin) are approved by the American Food and Drug Administration (FDA) and none by the European Medicines Agency (EMEA), consequently, off-label use is habitual in Europe. Most of the drugs improve only one or two symptoms; no drug capable of overall symptom control is yet available. Furthermore, different classes of drugs with different mechanisms of action are used off-label, including tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), opioids, non-steroidal anti-inflammatory drugs (NSAIDs), growth hormone, corticosteroids and sedative hypnotics. As no single drug fully manages FM symptoms, multicomponent therapy should be used from the beginning. Various pharmacological treatments have been used to treat FM with inconclusive results, and gradually increasing low doses is suggested in order to maximise efficacy. The best treatment should be individualised and combined with patient education and non-pharmacological therapy. |
301 | Which is the definition of pyknons in DNA? | Pyknons are non-random sequence patterns significantly repeated throughout non-coding genomic DNA, which have additional nonoverlapping instances in the untranslated and protein-coding regions. They are found more frequently in the 3' untranslated regions of genes than in other regions of the human genome. | [19833446, 16636294, 19229130, 19452047, 16751093, 19052667] | 408 | Small deletions and duplications frequently occur in the pericentromeric region of chromosomes and many of these are associated with developmental abnormalities. These developmental syndromes are conventionally attributed to abnormal expression of protein-coding genes in the affected region. A hypothesis has recently been published concerning a Master Development Program based on noncoding transcripts from these regions (Parris GE. A hypothetical Master Development Program for multi-cellular organisms: Ontogeny and phylogeny. Biosci Hypotheses 2009;2:3-12.). This paper summarizes and expands the recently published hypothesis to include it application to developmental diseases. The author proposes that development of multi-cellular organisms is guided by a Master Development Program (MDP) located primarily in the pericentromeric heterochromatin. The MDP is believed to consist of a series of Generation-Specific Control Keys (GSCK) transcribed in sequence by Ikaros family transcription factors unless the GSCKs are suppressed by Sall1-family or Dnmt3b-family proteins. The MDP is proposed to increment with each cell cycle to the next GSCK resulting in development of the clone. A clone may be programmed to split into two clones as necessary through a two-cycle mitosis processes. The transcripts of the GSCKs presumably yield noncoding nuclear messenger RNAs (nmRNAs, 8-30 nt units) that act directly (e.g., as primers for RNA polymerase II) and indirectly to regulate HOX and other high-level transcription factor and developmental genes. As envisioned, the MDP would evolve by terminal addition of new GSCKs. The new GSCKs are produced by evolutionary consolidation of retro-transcripts into pyknons that collect and evolve at the end of the pericentromeric heterochromatin and are eventually incorporated into the MDP. The retro-transcripts are though to be produced during episodic retrovirus epidemics and account for punctuated equilibrium in species evolution. Pyknons are non-random sequence patterns significantly repeated throughout non-coding genomic DNA that also appear at least once among coding genes. They are interesting because they portend an unforeseen connection between coding and non-coding DNA. Pyknons have only been discovered in the human genome, so it is unknown whether pyknons have wider biological relevance or are simply a phenomenon of the human genome. To address this, DNA sequence patterns from the Arabidopsis thaliana genome were detected using a probability-based method. 24 654 statistically significant sequence patterns, 16 to 24 nucleotides long, repeating 10 or more times in non-coding DNA also appeared in 46% of A. thaliana protein-coding genes. A. thaliana pyknons exhibit features similar to human pyknons, including being distinct sequence patterns, having multiple instances in genes and having remarkable similarity to small RNA sequences with roles in gene silencing. Chromosomal position mapping revealed that genomic pyknon density has concordance with siRNA and transposable element positioning density. Because the A. thaliana and human genomes have approximately the same number of genes but drastically different amounts of non-coding DNA, these data reveal that pyknons represent a biologically important link between coding and non-coding DNA. Because of the association of pyknons with siRNAs and localization to silenced regions of heterochromatin, we postulate that RNA-mediated gene silencing leads to the accumulation of gene sequences in non-coding DNA regions. We describe current research that applies epigenetics to a novel understanding of the immuno-neuropathogenesis of HIV-1 viral infection and NeuroAIDS. We propose the hypothesis that HIV-1 alters the structure-function relationship of chromatin, coding DNA and non-coding DNA, including RNA transcribed from these regions resulting in pathogenesis in AIDS, drug abuse, and NeuroAIDS. We discuss the general implications of molecular epigenetics with special emphasis on drug abuse, bar-codes, pyknons, and miRNAs for translational and clinical research. We discuss the application of the recent recursive algorithm of biology to this field and propose to synthesize the Genomic and Epigenomic views into a holistic approach of HoloGenomics. |
302 | Does a linker histone exist in the yeast genome? | Here, we present our results showing a connection between the linker histones, the higher-order chromatin structures, and the process of chronological lifespan of yeast cells. Characteristically, linker histone depleted chromatin generally exhibited longer chromatin loops than the wild-type. These results suggest that HHO1p may play a similar role to linker histones, but at restricted locations in the chromatin. The binding was structure specific, since the use of double-stranded DNA, or a mutant Hho1p in which the second DNA binding site of globular domain 1 was abolished, resulted in a significant decrease in bridged binding. | [9516420, 22586276, 15046982, 11471242, 24023978, 18687885, 15050829, 19017647, 22200500, 16342967, 11574687] | 409 | There is currently no published report on the isolation and definitive identification of histone H1 in Saccharomyces cerevisiae. It was, however, recently shown that the yeast HHO1 gene codes for a predicted protein homologous to H1 of higher eukaryotes (Landsman, D. (1996) Trends Biochem. Sci. 21, 287-288; Ushinsky, S. C., Bussey, H. , Ahmed, A. A., Wang, Y., Friesen, J., Williams, B. A., and Storms, R. K. (1997) Yeast 13, 151-161), although there is no biochemical evidence that shows that Hho1p is, indeed, yeast histone H1. We showed that purified recombinant Hho1p (rHho1p) has electrophoretic and chromatographic properties similar to linker histones. The protein forms a stable ternary complex with a reconstituted core di-nucleosome in vitro at molar rHho1p:core ratios up to 1. Reconstitution of rHho1p with H1-stripped chromatin confers a kinetic pause at approximately 168 base pairs in the micrococcal nuclease digestion pattern of the chromatin. These results strongly suggest that Hho1p is a bona fide linker histone. We deleted the HHO1 gene and showed that the strain is viable and has no growth or mating defects. Hho1p is not required for telomeric silencing, basal transcriptional repression, or efficient sporulation. Unlike core histone mutations, a hho1Delta strain does not exhibit a Sin or Spt phenotype. The absence of Hho1p does not lead to a change in the nucleosome repeat length of bulk chromatin nor to differences in the in vivo micrococcal nuclease cleavage sites in individual genes as detected by primer extension mapping. The differentiation of gametes involves dramatic changes to chromatin, affecting transcription, meiosis, and cell morphology. Sporulation in Saccharomyces cerevisiae shares many chromatin features with spermatogenesis, including a 10-fold compaction of the nucleus. To identify new proteins involved in spore nuclear organization, we purified chromatin from mature spores and discovered a significant enrichment of the linker histone (Hho1). The function of Hho1 has proven to be elusive during vegetative growth, but here we demonstrate its requirement for efficient sporulation and full compaction of the spore genome. Hho1 chromatin immunoprecipitation followed by sequencing (ChIP-seq) revealed increased genome-wide binding in mature spores and provides novel in vivo evidence of the linker histone binding to nucleosomal linker DNA. We also link Hho1 function to the transcription factor Ume6, the master repressor of early meiotic genes. Hho1 and Ume6 are depleted during meiosis, and analysis of published ChIP-chip data obtained during vegetative growth reveals a high binding correlation of both proteins at promoters of early meiotic genes. Moreover, Ume6 promotes binding of Hho1 to meiotic gene promoters. Thus, Hho1 may play a dual role during sporulation: Hho1 and Ume6 depletion facilitates the onset of meiosis via activation of Ume6-repressed early meiotic genes, whereas Hho1 enrichment in mature spores contributes to spore genome compaction. Biochemical studies to date have not been able to identify the linker histone H1 protein in the budding yeast Saccharomyces cerevisiae. Database homology searching against the complete yeast genome has identified a gene, HHO1, (or YPL127C, formerly LPI17) which encodes a protein that has two regions that show similarity to the pea histone H1 globular domain. To determine whether Hho1p can assume the shape of an H1 protein, homology model building experiments were performed using the structure of chicken histone H5 globular domain as the basis for comparison. A statistically significant match between each of the two globular domains of Hho1p and the chicken histone H5 structure was obtained, and probability values indicate that there is a less than 1 in 100 chance that such a match would be the result of a random event. These findings support the proposal that Hho1p acts as an "H1 dimer" and could be responsible for the decreased linker DNA length observed between nucleosomal core particles. Intricate, dynamic, and absolutely unavoidable ageing affects cells and organisms through their entire lifetime. Driven by diverse mechanisms all leading to compromised cellular functions and finally to death, this process is a challenge for researchers. The molecular mechanisms, the general rules that it follows, and the complex interplay at a molecular and cellular level are yet little understood. Here, we present our results showing a connection between the linker histones, the higher-order chromatin structures, and the process of chronological lifespan of yeast cells. By deleting the gene for the linker histone in Saccharomyces cerevisiae we have created a model for studying the role of chromatin structures mainly at its most elusive and so far barely understood higher-order levels of compaction in the processes of yeast chronological lifespan. The mutant cells demonstrated controversial features showing slower growth than the wild type combined with better survival during the whole process. The analysis of the global chromatin organization during different time points demonstrated certain loss of the upper levels of chromatin compaction in the cells without linker histone. The results underlay the importance of this histone for the maintenance of the chromatin loop structures during ageing. Nucleosome core particles in eukaryotes are linked by a stretch of DNA that is usually associated with a linker histone. Here, we show in yeast, that the presence of yeast linker histone Hho1p represses expression of a pol II transcribed gene (MET15) embedded in the rDNA. In vivo deletions of Hho1p sequences showed that the second globular domain is sufficient for that repression, whereas the presence of the N terminus is required for its derepression. In contrast, a run-on assay confirmed by a ChIP experiment showed that Hho1p is required for maximal pol I processivity during rDNA transcription. Psoralen accessibility experiments indicated that Hho1p is necessary for normal rDNA compaction. DNA array expression analysis comparing RNA transcripts in wild-type and hho1 strains before and after a heat-shock showed that Hho1p is necessary to achieve wild-type mRNA levels of transcripts that encode ribosomal components. Taken together, our results suggest that Hho1p is involved in rDNA compaction, and like core histones, is required for efficient rDNA transcription by pol I. Saccharomyces cerevisiae linker histone Hho1p is not essential for cell viability, and very little is known about its function in vivo. We show that deletion of HHO1 (hho1Delta) suppresses the defect in transcriptional silencing caused by a mutation in the globular domain of histone H4. hho1Delta also suppresses the reduction in HML silencing by the deletion of SIR1 that is involved in the establishment of silent chromatin at HML. We further show that hho1Delta suppresses changes in silent chromatin structure caused by the histone H4 mutation and sir1Delta. These results suggest that HHO1 plays a negative role in transcriptionally silent chromatin. We also provide evidence that Hho1p hinders the de novo establishment of silent chromatin but does not affect the stability of preexistent silent chromatin. Unlike canonical linker histones in higher eukaryotes that have a single conserved globular domain, Hho1p possesses two globular domains. We show that the carboxyl-terminal globular domain of Hho1p is dispensable for its function, suggesting that the mode of Hho1p action is similar to that of canonical linker histones. Despite the existence of certain differences between yeast and higher eukaryotic cells a considerable part of our knowledge on chromatin structure and function has been obtained by experimenting on Saccharomyces cerevisiae. One of the peculiarities of S. cerevisiae cells is the unusual and less abundant linker histone, Hho1p. Sparse is the information about Hho1p involvement in yeast higher-order chromatin organization. In an attempt to search for possible effects of Hho1p on the global organization of chromatin, we have applied Chromatin Comet Assay (ChCA) on HHO1 knock-out yeast cells. The results showed that the mutant cells exhibited highly distorted higher-order chromatin organization. Characteristically, linker histone depleted chromatin generally exhibited longer chromatin loops than the wild-type. According to the Atomic force microscopy data the wild-type chromatin appeared well organized in structures resembling quite a lot the "30-nm" fiber in contrast to HHO1 knock-out yeast. Saccharomyces cerevisiae encodes a single linker histone, Hho1p, with two globular domains. This raised the possibility that Hho1p could bind to two nucleosome cores simultaneously. To evaluate this idea, we studied the ability of a four-way junction, immobilized on the surface of a magnetic bead, to pull down a radiolabeled four-way junction in the presence of different Hho1 proteins. Four-way junctions are known to bind to H1, presumably due to structure similarities to the DNA at the nucleosomal entry/exit point. We found a significant increase in the ability of full-length Hho1p to pull down radiolabeled four-way junction DNA under ionic conditions where both globular domains could bind. The binding was structure specific, since the use of double-stranded DNA, or a mutant Hho1p in which the second DNA binding site of globular domain 1 was abolished, resulted in a significant decrease in bridged binding. Additionally, bridged binding required a covalent attachment between the two globular domains, since factor Xa protease treatment of the complex formed by a modified Hho1p that contained a factor Xa cleavage site between the two globular domains resulted in a significant release of radiolabeled four-way junction. These findings demonstrated that the two globular domains independently associated with two different four-way junction molecules in a manner that required amino acid residues implicated in structure-specific binding in the nucleosome. We discuss the implication of these findings on the chromatin structure of yeast and propose a model where a single Hho1 protein binds to two serially adjacent nucleosomes. In virtually all eukaryotic organisms, linker DNA between nucleosomes is associated with a histone termed linker histone or histone H1. In Saccharomyces cerevisiae, HHO1 encodes a putative linker histone with very significant homology to histone H1. The encoded protein is expressed in the nucleus, but has not been shown to affect global chromatin structure, nor has its deletion shown any detectable phenotype. In vitro chromatin assembly experiments with recombinant HHO1p have shown that it is able to complex with dinuncleosomes in a similar manner to histone H1. Here we report that while disruption of HHO1 has little affect on RNA levels of most cellular transcripts, there are numerous exceptions. Measurement of HHO1p concentration in the wild-type cell showed a stoichiometry of about one HHO1p molecule per 37 nucleosomes. Localization of HHO1p in the chromatin, using an immunoprecipitation technique, showed preferential HHO1p binding to rDNA sequences. These results suggest that HHO1p may play a similar role to linker histones, but at restricted locations in the chromatin. |
303 | What is the role of deadenylases in the cell? | The 3'-poly(A) tail, found on mRNAs, is enzymatically shortened by a process referred to as "deadenylation" which is carried out by deadenylases. Deadenylases are magnesium dependent exoribonucleases that specifically catalyze the degradation of eukaryotic mRNA poly(A) tail in the 3'-->5' direction with the release of 5'-AMP as the product. They consist of three potential RNA-binding domains: the catalytic nuclease domain, the R3H domain and the RRM domain. | [22834816, 19111172, 23224971, 22955276, 23221646, 18334997, 14970390, 19307292, 15475613, 18625844, 23496118, 12590136, 21984185, 23274303, 15247430, 22614729, 23019593, 21965533, 23388391, 18056425, 17090538] | 410 | Deadenylation is the exoribonucleolytic shortening of eukaryotic poly(A) tails. It is often the first and rate-limiting step for mRNA decay and translational silencing. The process is catalysed by a diversity of deadenylases, which provide robust and flexible means to control mRNA levels and gene expression. Poly(A)-specific ribonuclease (PARN) is a major mammalian deadenylase and the only known to concurrently bind the 5' cap-structure and the 3' poly(A), thus enhancing the degradation rate and amplifying its processivity. PARN is important during oocyte maturation, embryogenesis, early development, DNA damage, and in cell-cycle progression, but also in processes beyond mRNA metabolism, such as the maturation of snoRNAs. The enzyme also participates in nonsense-mediated mRNA decay and in the regulation of cytoplasmic polyadenylation. Importantly, PARN is involved in the degradation of several cancer-related genes, while its expression is altered in cancer. Apart from the direct interaction with the cap structure, several strategies regulate PARN activity, such as phosphorylation, interaction with RNA-binding proteins (RBPs), and natural nucleotides. Recent studies have focused on the regulation of its activity by synthetic nucleoside analogues with therapeutic potential. In this context, the wide repertoire of RBPs and molecules that regulate PARN activity, together with the established role of deadenylases in miRNA-mediated regulation of mRNA expression, suggest that mRNA turnover is more complex than it was previously thought and PARN holds a key role in this process. In this review, we highlight the importance of PARN during RNA's lifecycle and discuss clinical perspectives of modulating its activity. Deadenylation is the major step in triggering mRNA decay and results in mRNA translation inhibition in eukaryotic cells. Therefore, it is plausible that deadenylation also induces the mRNP remodeling required for formation of GW bodies or RNA processing bodies (P-bodies), which harbor translationally silenced mRNPs. In this chapter, we discuss several examples to illustrate the roles of deadenylation in regulating gene expression. We highlight several lines of evidence indicating that even though non-translatable mRNPs may be prepared and/or assembled into P-bodies in different ways, deadenylation is always a necessary, and perhaps the earliest, step in mRNA decay pathways that enable mRNP remodeling required for P-body formation. Thus, deadenylation and the participating deadenylases are not simply required for preparing mRNA substrates; they play an indispensable role both structurally and functionally in P-body formation and regulation. PUF proteins are a conserved family of eukaryotic RNA-binding proteins that regulate specific mRNAs: they control many processes including stem cell proliferation, fertility, and memory formation. PUFs repress protein expression from their target mRNAs but the mechanism by which they do so remains unclear, especially for humans. Humans possess two PUF proteins, PUM1 and PUM2, which exhibit similar RNA binding specificities. Here we report new insights into their regulatory activities and mechanisms of action. We developed functional assays to measure sequence-specific repression by PUM1 and PUM2. Both robustly inhibit translation and promote mRNA degradation. Purified PUM complexes were found to contain subunits of the CCR4-NOT (CNOT) complex, which contains multiple enzymes that catalyze mRNA deadenylation. PUMs interact with the CNOT deadenylase subunits in vitro. We used three approaches to determine the importance of deadenylases for PUM repression. First, dominant-negative mutants of CNOT7 and CNOT8 reduced PUM repression. Second, RNA interference depletion of the deadenylases alleviated PUM repression. Third, the poly(A) tail was necessary for maximal PUM repression. These findings demonstrate a conserved mechanism of PUF-mediated repression via direct recruitment of the CCR4-POP2-NOT deadenylase leading to translational inhibition and mRNA degradation. A second, deadenylation independent mechanism was revealed by the finding that PUMs repress an mRNA that lacks a poly(A) tail. Thus, human PUMs are repressors capable of deadenylation-dependent and -independent modes of repression. The degradation of most eukaryotic mRNAs is initiated by removal of the poly(A) tail, and the major deadenylase activity is associated with the CCR4/CAF1/NOT complex (NOT complex). We here study the role of CNOT10, a protein that is found in human and trypanosome, but not in yeast, NOT complexes. Trypanosome (Tb) CNOT10 is essential for growth. TbCNOT10 interacted with the deadenylase TbCAF1 and the scaffold protein TbNOT1; TbCAF1 also interacted with TbNOT1 in a yeast two-hybrid assay. In both trypanosomes and human embryonic kidney cells, approximately half of CAF1 was associated with the NOT complex. Depletion of CNOT10 from human cells did not affect this association. In contrast, depletion of TbCNOT10 in trypanosomes caused a decrease in the level of TbNOT1, detachment of TbCAF1 from the complex and pronounced stabilization of most trypanosome mRNAs. Artificial tethering of TbCAF1 to a reporter mRNA in vivo resulted in mRNA degradation, and this was not affected by TbCNOT10 depletion. We conclude that in trypanosomes, TbCNOT10 may stabilize the interaction between TbCAF1 and the NOT complex. The results further suggest that TbCAF1 is only able to deadenylate mRNA in vivo if it is recruited to the mRNA through other NOT complex components. The stability of mRNAs is an important point in the regulation of gene expression in eukaryotes. The mRNA turnover pathways have been identified in yeast and mammals. However, mRNA turnover pathways in trypanosomes have not been widely studied. Deadenylation is the first step in the major mRNA turnover pathways of yeast and mammals. To better understand mRNA degradation processes in these organisms, we have developed an in vitro mRNA turnover system that is functional for deadenylation. In this system, addition of poly(A) homopolymer activates the deadenylation of poly(A) tails. The trypanosomal deadenylase activity is a 3'-->5' exonuclease specific for adenylate residues, generates 5'-AMP as a product, is magnesium dependent, and is inhibited by neomycin B sulfate. These characteristics suggest similarity with other eukaryotic deadenylases. Furthermore, this activity is cap independent, indicating a potential difference between the trypanosomal activity and PARN, but suggesting similarity to Ccr4p/Pop2p activities. Extracts immunodepleted of Pab1p required the addition of poly(A) competition to activate deadenylation. Trypanosomal Pab1p functions as an inhibitor of the activity under in vitro conditions. Pab1p appears to be one of several mRNA stability proteins in trypanosomal extracts. In eukaryotic organisms, initiation of mRNA turnover is controlled by progressive shortening of the poly-A tail, a process involving the mega-Dalton Ccr4-Not complex and its two associated 3'-5' exonucleases, Ccr4p and Pop2p (Caf1p). RNA degradation by the 3'-5' DEDDh exonuclease, Pop2p, is governed by the classical two metal ion mechanism traditionally assumed to be dependent on Mg(2+) ions bound in the active site. Here, we show biochemically and structurally that fission yeast (Schizosaccharomyces pombe) Pop2p prefers Mn(2+) and Zn(2+) over Mg(2+) at the concentrations of the ions found inside cells and that the identity of the ions in the active site affects the activity of the enzyme. Ion replacement experiments further suggest that mRNA deadenylation could be subtly regulated by local Zn(2+) levels in the cell. Finally, we use site-directed mutagenesis to propose a mechanistic model for the basis of the preference for poly-A sequences exhibited by the Pop2p-type deadenylases as well as their distributive enzymatic behavior. The majority of messenger RNA (mRNA) decay in mammalian cells appears to be the work of a series of RNA exoribonucleases. A set of multiple poly(A)-specific deadenylases has been identified, some, if not most, of which are likely to play a role in the key first step of mRNA turnover--the regulated shortening of the poly(A) tail. After deadenylation, the transcript likely gets degraded by either a 5'-to-3' or a 3'-to-5' exonucleolytic pathway. Interestingly, multiple exonucleases have been identified for both of these pathways that appear to form multicomponent complexes with diverse roles in cellular biology. Therefore these enzymes appear not only to be important components of the mRNA turnover machinery, but also may function in a networked fashion in the post-transcriptional control of gene expression. Deadenylation is the major step triggering mammalian mRNA decay. One consequence of deadenylation is the formation of nontranslatable messenger RNA (mRNA) protein complexes (messenger ribonucleoproteins [mRNPs]). Nontranslatable mRNPs may accumulate in P-bodies, which contain factors involved in translation repression, decapping, and 5'-to-3' degradation. We demonstrate that deadenylation is required for mammalian P-body formation and mRNA decay. We identify Pan2, Pan3, and Caf1 deadenylases as new P-body components and show that Pan3 helps recruit Pan2, Ccr4, and Caf1 to P-bodies. Pan3 knockdown causes a reduction of P-bodies and has differential effects on mRNA decay. Knocking down Caf1 or overexpressing a Caf1 catalytically inactive mutant impairs deadenylation and mRNA decay. P-bodies are not detected when deadenylation is blocked and are restored when the blockage is released. When deadenylation is impaired, P-body formation is not restorable, even when mRNAs exit the translating pool. These results support a dynamic interplay among deadenylation, mRNP remodeling, and P-body formation in selective decay of mammalian mRNA. Deadenylation of eukaryotic mRNA is a mechanism critical for mRNA function by influencing mRNA turnover and efficiency of protein synthesis. Here, we review poly(A)-specific ribonuclease (PARN), which is one of the biochemically best characterized deadenylases. PARN is unique among the currently known eukaryotic poly(A) degrading nucleases, being the only deadenylase that has the capacity to directly interact during poly(A) hydrolysis with both the m(7)G-cap structure and the poly(A) tail of the mRNA. In short, PARN is a divalent metal-ion dependent poly(A)-specific, processive and cap-interacting 3'-5' exoribonuclease that efficiently degrades poly(A) tails of eukaryotic mRNAs. We discuss in detail the mechanisms of its substrate recognition, catalysis, allostery and processive mode of action. On the basis of biochemical and structural evidence, we present and discuss a working model for PARN action. Models of regulation of PARN activity by trans-acting factors are discussed as well as the physiological relevance of PARN. The CCR4 family proteins are 3'-5'-deadenylases that function in the first step of the degradation of poly(A) mRNA. Here we report the purification to homogeneity of the yeast CCR4 protein and the analysis of its substrate specificities. CCR4 deadenylated a 7N+23A substrate (seven nucleotides followed by 23 A residues) in a distributive manner. Only small differences in CCR4 activity for different A length substrates were observed until only 1 A residue remained. Correspondingly, the K(m) for a 25N+2A substrate was found to be at least 20-fold lower than that for a 26N+1A substrate, although their V(max) values differed by only 2-fold. In addition, the total length of the RNA was found to contribute to CCR4 activity: up to 17 nucleotides (not necessarily poly(A)) could be recognized by CCR4. Poly(U), poly(C), and poly(G) were also found to be 12-30-fold better inhibitors of CCR4 compared with poly(A), supporting the observation that CCR4 contains a non-poly(A)-specific binding site. Surprisingly, even longer substrates (>/=45 nucleotides) stimulated CCR4 to become a processive enzyme, suggesting that CCR4 undergoes an additional transition in the presence of such substrates. CCR4 also displayed no difference in its activity with capped or uncapped RNA substrates. These results indicate that CCR4 recognition of its RNA substrates involves several features of the RNA that could be sites in vivo for controlling the rate of specific mRNA deadenylation. PARN, Nocturnin and Angel are three of the multiple deadenylases that have been described in eukaryotic cells. While each of these enzymes appear to target poly(A) tails for shortening and influence RNA gene expression levels and quality control, the enzymes differ in terms of enzymatic mechanisms, regulation and biological impact. The goal of this review is to provide an in depth biochemical and biological perspective of the PARN, Nocturnin and Angel deadenylases. Understanding the shared and unique roles of these enzymes in cell biology will provide important insights into numerous aspects of the post-transcriptional control of gene expression. This article is part of a Special Issue entitled: RNA Decay mechanisms. Deadenylation of mRNA is often the first and rate-limiting step in mRNA decay. PARN, a poly(A)-specific 3' --> 5' ribonuclease which is conserved in many eukaryotes, has been proposed to be primarily responsible for such a reaction, yet the importance of the PARN function at the whole-organism level has not been demonstrated in any species. Here, we show that mRNA deadenylation by PARN is essential for viability in higher plants (Arabidopsis thaliana). Yet, this essential requirement for the PARN function is not universal across the phylogenetic spectrum, because PARN is dispensable in Fungi (Schizosaccharomyces pombe), and can be at least severely downregulated without any obvious consequences in Metazoa (Caenorhabditis elegans). Development of the Arabidopsis embryos lacking PARN (AtPARN), as well as of those expressing an enzymatically inactive protein, was markedly retarded, and ultimately culminated in an arrest at the bent-cotyledon stage. Importantly, only some, rather than all, embryo-specific transcripts were hyperadenylated in the mutant embryos, suggesting that preferential deadenylation of a specific select subset of mRNAs, rather than a general deadenylation of the whole mRNA population, by AtPARN is indispensable for embryogenesis in Arabidopsis. These findings indicate a unique, nonredundant role of AtPARN among the multiple plant deadenylases. BACKGROUND/AIMS: The degradation of mRNA is a key process in the control of gene expression correlated to anomalous cell proliferation. The rate-limiting step of mRNA degradation is the removal of the poly(A) tail by deadenylases. However, studies on deadenylase expression in cancer are limited. Herein, we analyzed the expression of several deadenylases from acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). METHODS: Clinical samples from patients diagnosed with ALL and AML were the source of leukemic cells. Extracts from leukemic and control cells were analyzed for deadenylase mRNA levels using qRT-PCR, and the protein levels of PARN and CNOT7 deadenylases using immunoblotting. RESULTS: RT-PCR analysis revealed altered expression for CNOT6, CNOT6L, CNOT7 and PARN deadenylases. The most significant alterations were observed for PARN and CNOT7 mRNA levels, which also reflect on the cognate protein level. Further analysis revealed that a significant amount of PARN is phosphorylated in ALL. CONCLUSIONS: We show that the expression of several deadenylases in acute leukemias is altered. The increase of PARN expression and the alteration of its phosphorylation status indicate important regulatory events. These data suggest that the role of deadenylases as auxiliary biomarkers and therapeutic targets should be meticulously investigated. Eukaryotic releasing factor GSPT/eRF3 mediates translation termination-coupled mRNA decay via interaction with a cytosolic poly(A)-binding protein (PABPC1). A region of eRF3 containing two overlapping PAM2 (PABPC1-interacting motif 2) motifs is assumed to bind to the PABC domain of PABPC1, on the poly(A) tail of mRNA. PAM2 motifs are also found in the major deadenylases Caf1-Ccr4 and Pan2-Pan3, whose activities are enhanced upon PABPC1 binding to these motifs. Their deadenylase activities are regulated by eRF3, in which two overlapping PAM2 motifs competitively prevent interaction with PABPC1. However, it is unclear how these overlapping motifs recognize PABC and regulate deadenylase activity in a translation termination-coupled manner. We used a dominant-negative approach to demonstrate that the N-terminal PAM2 motif is critical for eRF3 binding to PABPC1 and that both motifs are required for function. Isothermal titration calorimetry (ITC) and NMR analyses revealed that the interaction is in equilibrium between the two PAM2-PABC complexes, where only one of the two overlapping PAM2 motifs is PABC-bound and the other is PABC-unbound and partially accessible to the other PABC. Based on these results, we proposed a biological role for the overlapping PAM2 motifs in the regulation of deadenylase accessibility to PABPC1 at the 3' end of poly(A). Deadenylation is the first and rate-limiting step during turnover of mRNAs in eukaryotes. In the yeast, Saccharomyces cerevisiae, two distinct 3'-5' exonucleases, Pop2p and Ccr4p, have been identified within the Ccr4-NOT deadenylase complex, belonging to the DEDD and Exonuclease-Endonuclease-Phosphatase (EEP) families, respectively. Ngl3p has been identified as a new member of the EEP family of exonucleases based on sequence homology, but its activity and biological roles are presently unknown. Here, we show using in vitro deadenylation assays on defined RNA species mimicking poly-A containing mRNAs that yeast Ngl3p is a functional 3'-5' exonuclease most active at slightly acidic conditions. We further show that the enzyme depends on divalent metal ions for activity and possesses specificity towards poly-A RNA similar to what has been observed for cellular deadenylases. The results suggest that Ngl3p is naturally involved in processing of poly-adenylated RNA and provide insights into the mechanistic variations observed among the redundant set of EEP enzymes found in yeast and higher eukaryotes. Deadenylases specifically catalyze the degradation of eukaryotic mRNA poly(A) tail in the 3'- to 5'-end direction with the release of 5'-AMP as the product. Among the deadenylase family, poly(A)-specific ribonuclease (PARN) is unique in its domain composition, which contains three potential RNA-binding domains: the catalytic nuclease domain, the R3H domain and the RRM domain. In this research, we investigated the roles of these RNA-binding domains by comparing the structural features and enzymatic properties of mutants lacking either one or two of the three RNA-binding domains. The results showed that the R3H domain had the ability to bind various oligonucleotides at the micromolar level with no oligo(A) specificity. The removal of the R3H domain dissociated PARN into monomers, which still possessed the RNA-binding ability and catalytic functions. Unlike the critical role of the RRM domain in PARN processivity, the removal of the R3H domain did not affect the catalytic pattern of PARN. Our results suggested that both R3H and RRM domains were essential for the high affinity of long poly(A) substrate, but the R3H domain did not contribute to the substrate recognition of PARN. Compared to the RRM domain, the R3H domain played a more important role in the structural integrity of the dimeric PARN. The multiple RNA-binding domain architecture endows PARN the property of highly efficient catalysis in a highly processive mode. PUF proteins control gene expression by binding to the 3'-untranslated regions of specific mRNAs and triggering mRNA decay or translational repression. Here we focus on the mechanism of PUF-mediated regulation. The yeast PUF protein, Mpt5p, regulates HO mRNA and stimulates removal of its poly(A) tail (i.e. deadenylation). Mpt5p repression in vivo is dependent on POP2, a component of the cytoplasmic Ccr4p-Pop2p-Not complex that deadenylates mRNAs. In this study, we elucidate the individual roles of the Ccr4p and Pop2p deadenylases in Mpt5p-regulated deadenylation. Both in vivo and in vitro, Pop2p and Ccr4p proteins are required for Mpt5p-regulated deadenylation of HO. However, the requirements for the two proteins differ dramatically: the enzymatic activity of Ccr4p is essential, whereas that of Pop2p is dispensable. We conclude that Pop2p is a bridge through which the PUF protein recruits the Ccr4p enzyme to the target mRNA, thereby stimulating deadenylation. Our data suggest that PUF proteins may enhance mRNA degradation and repress expression by both deadenylation-dependent and -independent mechanisms, using the same Pop2p bridge to recruit a multifunctional Pop2p complex to the mRNA. |
304 | What molecule is targeted by brodalumab? | Interleukin-17. Brodalumab is anti interleukin-17 monoclonal antibody. | [26422722, 25713988, 24918373, 25599143, 24200404, 25246805, 22455412, 24646743, 25093016, 24552447] | 411 | BACKGROUND: Early clinical studies suggested that the anti-interleukin-17 receptor A monoclonal antibody brodalumab has efficacy in the treatment of psoriasis. METHODS: In two phase 3 studies (AMAGINE-2 and AMAGINE-3), patients with moderate-to-severe psoriasis were randomly assigned to receive brodalumab (210 mg or 140 mg every 2 weeks), ustekinumab (45 mg for patients with a body weight ≤100 kg and 90 mg for patients >100 kg), or placebo. At week 12, patients receiving brodalumab were randomly assigned again to receive a brodalumab maintenance dose of 210 mg every 2 weeks or 140 mg every 2 weeks, every 4 weeks, or every 8 weeks; patients receiving ustekinumab continued to receive ustekinumab every 12 weeks, and patients receiving placebo received 210 mg of brodalumab every 2 weeks. The primary aims were to evaluate the superiority of brodalumab over placebo at week 12 with respect to at least a 75% reduction in the psoriasis area-and-severity index score (PASI 75) and a static physician's global assessment (sPGA) score of 0 or 1 (clear or almost clear skin), as well as the superiority of brodalumab over ustekinumab at week 12 with respect to a 100% reduction in PASI score (PASI 100). RESULTS: At week 12, the PASI 75 response rates were higher with brodalumab at the 210-mg and 140-mg doses than with placebo (86% and 67%, respectively, vs. 8% [AMAGINE-2] and 85% and 69%, respectively, vs. 6% [AMAGINE-3]; P<0.001); the rates of sPGA scores of 0 or 1 were also higher with brodalumab (P<0.001). The week 12 PASI 100 response rates were significantly higher with 210 mg of brodalumab than with ustekinumab (44% vs. 22% [AMAGINE-2] and 37% vs. 19% [AMAGINE-3], P<0.001). The PASI 100 response rates with 140 mg of brodalumab were 26% in AMAGINE-2 (P=0.08 for the comparison with ustekinumab) and 27% in AMAGINE-3 (P=0.007). Rates of neutropenia were higher with brodalumab and with ustekinumab than with placebo. Mild or moderate candida infections were more frequent with brodalumab than with ustekinumab or placebo. Through week 52, the rates of serious infectious episodes were 1.0 (AMAGINE-2) and 1.3 (AMAGINE-3) per 100 patient-years of exposure to brodalumab. CONCLUSIONS: Brodalumab treatment resulted in significant clinical improvements in patients with moderate-to-severe psoriasis. (Funded by Amgen; AMAGINE-2 and AMAGINE-3 ClinicalTrials.gov numbers, NCT01708603 and NCT01708629.). Psoriasis is a common chronic inflammatory disease of the skin. Current biologic therapies are highly effective in the treatment of psoriasis, transforming the lives of patients with this significantly disabling disease. Advances in the understanding of the immunological pathogenesis of psoriasis have led to the development of new biologic therapies, targeting specific inflammatory cytokines upregulated in psoriasis. These include the IL-17 antagonists, secukinumab, brodalumab and ixekizumab; the IL-23 antagonists, guselkumab and tildrakizumab; and the oral small molecule therapies, tofacitinib and apremilast. Here, we review evidence for the efficacy and safety of these novel psoriasis therapies, providing clinicians with an overview of the next era in immunotherapy for psoriasis. BACKGROUND: We assessed the efficacy and safety of brodalumab, a human monoclonal antibody against interleukin-17 receptor A (IL17RA), in a phase 2, randomized, double-blind, placebo-controlled study involving patients with psoriatic arthritis. METHODS: We randomly assigned patients with active psoriatic arthritis to receive brodalumab (140 or 280 mg subcutaneously) or placebo on day 1 and at weeks 1, 2, 4, 6, 8, and 10. At week 12, patients who had not discontinued their participation in the study were offered open-label brodalumab (280 mg) every 2 weeks. The primary end point was 20% improvement in American College of Rheumatology response criteria (ACR 20) at week 12. RESULTS: Of the 168 patients who underwent randomization (57 in the brodalumab 140-mg group, 56 in the brodalumab 280-mg group, and 55 in the placebo group), 159 completed the double-blind phase and 134 completed 40 weeks of the open-label extension. At week 12, the brodalumab 140-mg and 280-mg groups had higher rates of ACR 20 than the placebo group (37% [P=0.03] and 39% [P=0.02], respectively, vs. 18%); they also had higher rates of 50% improvement (ACR 50) (14% [P=0.05] and 14% [P=0.05] vs. 4%). Rates of 70% improvement were not significantly higher in the brodalumab groups. Similar degrees of improvement were noted among patients who had received previous biologic therapy and those who had not received such therapy. At week 24, ACR 20 response rates in the brodalumab 140-mg and 280-mg groups were 51% and 64%, respectively, as compared with 44% among patients who switched from placebo to open-label brodalumab; responses were sustained through week 52. At week 12, serious adverse events had occurred in 3% of patients in the brodalumab groups and in 2% of those in the placebo group. CONCLUSIONS: Brodalumab significantly improved response rates among patients with psoriatic arthritis. Larger studies of longer duration are necessary to assess adverse events. (Funded by Amgen; ClinicalTrials.gov number, NCT01516957 .). PURPOSE OF REVIEW: In recent years, there has been an increasing understanding of the importance of the TH17 lineage of T cells and related cytokines, including interleukin (IL)17 and IL23, not only in the biology of innate host defense but also in the pathogenesis of inflammatory/autoimmune diseases. These diseases include psoriasis, psoriatic arthritis, the broader category of spondyloarthritides including ankylosing spondylitis and rheumatoid arthritis. It is postulated that in genetically predisposed individuals, external or internal stimuli such as microbial antigens, alterations in the intestinal microbiome, biomechanical stress and/or immunologic dysregulation may lead to an increased expression of cytokines such as IL23, which in turn stimulate the differentiation and activation of TH17 and other immune cells, which are a part of the innate immune system that trigger adaptive immune processes and chronic inflammatory diseases. Herein, we explore the effect of targeting this pathway therapeutically. RECENT FINDINGS: New drugs that are designed to inhibit steps in this pathway, the IL12/IL23 inhibitor, ustekinumab, the IL17A inhibitors secukinumab and ixekizumab, the IL17A receptor inhibitor, brodalumab, and the IL23 inhibitors guselkumab and tildrakizumab, have demonstrated significant effectiveness in treating these diseases, particularly psoriasis, psoriatic arthritis and ankylosing spondylitis. SUMMARY: This article reviews the relevant biology, efficacy and safety of new medications targeting the TH17 pathway, including inhibition of IL17 and IL23, particularly in psoriasis and psoriatic arthritis. Especially for patients who have not gained benefit from, lost effectiveness to or could not use antitumour necrosis factor (TNF) medications for safety or tolerability reasons, having effective medicines with an alternative mechanism of action will improve our ability to diminish disease activity impact on patient lives. RATIONALE: IL-17 signaling has been implicated in development and persistence of asthma. Cytokine-targeted strategies blocking IL-17 receptor signaling may be beneficial in asthma treatment. OBJECTIVES: To determine efficacy and safety of brodalumab, a human anti-IL-17 receptor A monoclonal antibody, in subjects with inadequately controlled moderate to severe asthma taking regular inhaled corticosteroids. METHODS: Three hundred two subjects were randomized to brodalumab (140, 210, or 280 mg) or placebo. Primary endpoint was change in Asthma Control Questionnaire (ACQ) score from baseline to Week 12. Secondary endpoints included FEV1, symptom scores, and symptom-free days. Prespecified subgroup analyses were conducted to identify potential responsive subpopulations. Analyses included randomized subjects receiving one or more doses of investigational product using last-observation-carried-forward imputation. MEASUREMENTS AND MAIN RESULTS: Demographics and baseline characteristics were generally balanced among groups (n = 302; n = 226 brodalumab). For the overall study population, no treatment differences were observed. Nine prespecified subgroups were examined without corrections for multiple testing. In only the high-reversibility subgroup (post-bronchodilator FEV1 improvement ≥ 20%; n = 112) was an ACQ change with nominal significance noted; ACQ responses were nominally significant in the 210-mg group (estimated treatment difference, 0.53) but not significant in the higher 280-mg group (estimated treatment difference, 0.38). Adverse events, generally balanced among groups, were most commonly asthma, upper respiratory tract infection, and injection site reaction. CONCLUSIONS: Inhibition of IL-17 receptor A did not produce a treatment effect in subjects with asthma. The results of the high-reversibility subgroup analysis are of uncertain significance, requiring further study of brodalumab in this asthma subpopulation. Clinical trial registered with www.clinicaltrials.gov (NCT01199289). "Psoriasis" is a chronic immune-mediated inflammatory disorder with epidermal hyperplasia. There is some evidence that the cytokine interleukin-17A (often known as IL-17), which is mainly produced by Th17 cells, has a role in the pathogenesis of psoriasis. "IL-17" is a pro-inflammatory cytokine mainly important in the host's defense against extracellular bacteria and fungi. The three new therapies with biologic drugs - brodalumab, secukinumab, and ixekizumab - all target the IL-17 signaling pathway. Secukinumab and ixekizumab neutralize IL-17A, while brodalumab blocks its receptor. Results from clinical trials have shown marked improvements in disease severity in patients with moderate-to-severe plaque psoriasis, using any of these three drugs. The biologic agents were generally well tolerated, but the duration of the trials was relatively short. In this review, we focus on the role of the IL-17 cytokine family in the pathogenesis of psoriasis; the efficacy, safety, and tolerability of brodalumab, secukinumab, and ixekizumab in clinical trials; and possible differences between targeting of the IL-17A receptor and targeting of the IL-17A ligand. BACKGROUND: In this phase 2, randomized, double-blind, placebo-controlled, dose-ranging study, we assessed the efficacy and safety of brodalumab (AMG 827), a human anti-interleukin-17-receptor monoclonal antibody, for the treatment of moderate-to-severe plaque psoriasis. METHODS: We randomly assigned patients with a score of 12 or higher on the psoriasis area-and-severity index (PASI, on which scores range from 0 to 72, with higher scores indicating more severe disease) and with 10% or more of their body-surface area affected by psoriasis to receive brodalumab (70 mg, 140 mg, or 210 mg at day 1 and weeks 1, 2, 4, 6, 8, and 10 or 280 mg monthly) or placebo. The primary end point was the percentage improvement from baseline in the PASI score at week 12. Secondary end points included improvement of at least 75% and at least 90% in the PASI score and the score on the static physician's global assessment at week 12. RESULTS: A total of 198 patients underwent randomization. At week 12, the mean percentage improvements in the PASI score were 45.0% among patients receiving 70 mg of brodalumab, 85.9% among those receiving 140 mg, 86.3% among those receiving 210 mg, 76.0% among those receiving 280 mg, and 16.0% among those receiving placebo (P<0.001 for all comparisons with placebo). An improvement of at least 75% and at least 90% in the PASI score at week 12 was seen in 77% and 72%, respectively, of the patients in the 140-mg brodalumab group and in 82% and 75%, respectively, of the patients in the 210-mg group, as compared with 0% in the placebo group (P<0.001 for all comparisons). The percentage of patients with a static physician's global assessment of clear or minimal disease was 26%, 85%, 80%, and 69% with the 70-mg, 140-mg, 210-mg, and 280-mg doses, respectively, of brodalumab, as compared with 3% with placebo (P<0.01 for all comparisons with placebo). Two cases of grade 3 neutropenia were reported in the 210-mg brodalumab group. The most commonly reported adverse events in the combined brodalumab groups were nasopharyngitis (8%), upper respiratory tract infection (8%), and injection-site erythema (6%). CONCLUSIONS: Brodalumab significantly improved plaque psoriasis in this 12-week, phase 2 study. (Funded by Amgen; ClinicalTrials.gov number, NCT00975637.). The IL-17 pathway is an established driver of psoriasis pathogenesis. We examined the detailed molecular and cellular effects of blockade of IL-17 signaling in human psoriatic skin before and following treatment with brodalumab, a competitive inhibitor of the IL-17 Receptor A subunit. Thousands of aberrantly expressed genes in lesional skin normalized within 2 weeks following brodalumab treatment, with conversion of the lesional psoriasis transcriptome to resemble that seen in nonlesional skin. Keratinocyte-expressed genes appeared to normalize rapidly, whereas T cell-specific normalization occurred over six weeks. The three IL-17 ligand genes that are upregulated in lesional skin, IL17A, IL17C, and IL17F, were all downregulated in a dose-dependent manner following brodalumab treatment. Cellular measures also showed a similar pattern with dramatic decreases in keratinocyte hyperplasia within one week, and decreases in infiltrating leukocytes occurred over a longer timescale. Individuals with the highest brodalumab exposure showed normalization of both IL-17-responsive genes and the psoriasis transcriptome, whereas subjects with lower exposures showed transient or incomplete molecular responses. Clinical and molecular response appeared dependent on the extent of brodalumab exposure relative to the expression of IL-17 ligand genes, and reduction of IL-17 signaling into the nonlesional range was strongly correlated with normalization of the psoriasis transcriptome. These data indicate that blockade of IL-17 signaling in psoriatic skin leads to rapid transcriptomal changes initially in keratinocyte-expressed genes, followed by normalization in the leukocyte abnormalities, and demonstrates the essential role of the IL-17R on keratinocytes in driving disease pathogenesis. Advances in knowledge regarding the pathogenesis of psoriasis have allowed the development of a new class of agents known as biologic drugs. Data confirm that T helper (Th)17 and interleukin (IL)-17 signaling has a crucial role in the pathogenesis of the disease. High levels of IL-17 and Th17-related cytokines have been reported in psoriasis, leading to the suggestion of agents targeting IL-17 as a potential therapeutic strategy in psoriasis. Brodalumab is a human monoclonal antibody that targets IL-17 receptor A, blocking the effects of IL-17A, IL-17F, and IL-17E. Data from Phase I and Phase II clinical trials indicate that brodalumab has a favorable safety and tolerability profile, with strong clinical activity, suggesting that it is a potential tool for use in the treatment of moderate-to-severe psoriasis. Abstract Background: Studies investigating the molecular basis of psoriasis have established the central roles of TNFα, interleukin (IL)-12, IL-22 and IL-23 and there is increasing evidence that IL-17 plays a critical role in the complex pathophysiology. Preclinical studies suggest that IL-17 is a desirable therapeutic target for psoriasis treatment. METHODS: We reviewed the results of the phase II clinical trials for the anti-IL-17 agents secukinumab, ixekizumab and brodalumab in order to assess the efficacy and safety profile of each agent. RESULTS: By week 12, the proportion of patients reaching Psoriasis Area and Severity Index (PASI 75) was comparable among the most efficacious dosage between the different agents (secukinumab 82%, ixekizumab 83% and brodalumab 82%; p<0.001 compared to placebo for all agents). The safety profiles of the agents were similar with the most frequently reported adverse events of nasopharyngitis, upper respiratory infections and injection site reaction. A small percentage of patients experienced low-grade neutropenia that was predominantly transient and asymptomatic. CONCLUSION: The anti-IL-17 agents demonstrated a rapid and robust clinical improvement accompanied by a favorable short-term safety profile. The results of the phase II trials support the theory that the IL-17 pathway is an essential target in psoriasis treatment. |
305 | How long, in kb (kilobases), is a "Long interspersed nuclear element"? | The retrotransposon known as long interspersed nuclear element-1 (L1) is 6-7 kb long, | [11810275, 21916613, 21637438] | 412 | Leukemic cells of a patient diagnosed with chronic myeloid leukemia (CML) showed a complex BCR-ABL1 rearrangement hidden within a normal appearing karyotype. Previous molecular studies had established that the 3' BCR had recombined at a novel site within the variable region of the immunoglobulin lambda locus ( IGL). A segment of DNA mapping very close to the site of the IGL/3' BCR recombination recognized a previously undescribed insertion polymorphism. A combination of molecular hybridization studies and long-range polymerase chain reaction was used to isolate a 6-kb full-length long interspersed nuclear element (LINE or L1), here designated L1(IGL), which occupies 19% of alleles in the general population. Although unclonable, DNA sequence analysis by a primer walking approach established that L1(IGL) has features characteristic of an actively retrotransposing element. The L1(IGL) element has a 5' untranslated region, two open reading frames (ORF-1 and ORF-2), a 3' untranslated region and terminates in a poly-A tail. We compared the DNA sequence and the predicted amino acid sequence of L1(IGL) with a consensus sequence compiled from seven reported active L1 elements. This analysis indicated that L1(IGL) has high potential for involvement in as yet undetermined somatically and constitutionally acquired disease, not only through recombination mechanisms, but also through retrotransposition events. This full-length L1 element maps close within the IGLlocus to L1.2, one of only nine active L1 elements that have been reported so far. L1(IGL) and L1.2 map within a wider and well-recognized region of genomic instability on chromosome 22. A typical eukaryotic genome harbors a rich variety of repetitive elements. The most abundant are retrotransposons, mobile retroelements that utilize reverse transcriptase and an RNA intermediate to relocate to a new location within the cellular genomes. A vast majority of the repetitive mammalian genome content has originated from the retrotransposition of SINE (100-300 bp short interspersed nuclear elements that are derived from the structural 7SL RNA or tRNA), LINE (7kb long interspersed nuclear element), and LTR (2-3 kb long terminal repeats) transposable element superfamilies. Broadly labeled as "evolutionary junkyard" or "fossils", this enigmatic "dark matter" of the genome possesses many yet to be discovered properties. The retrotransposon known as long interspersed nuclear element-1 (L1) is 6 kb long, although most L1s in mammalian and other eukaryotic cells are truncated. L1 contains two open reading frames, ORF1 and ORF2, that code for an RNA-binding protein and a protein with endonuclease and reverse transcriptase activities, respectively. In this work, we examined the effects of full length L1-ORF2 and ORF2 fragments on green fluorescent protein gene (GFP) expression when inserted into the pEGFP-C1 vector downstream of GFP. All of the ORF2 fragments in sense orientation inhibited GFP expression more than when in antisense orientation, which suggests that small ORF2 fragments contribute to the distinct inhibitory effects of this ORF on gene expression. These results provide the first evidence that different 280-bp fragments have distinct effects on the termination of gene transcription, and that when inserted in the antisense direction, fragment 280-9 (the 3' end fragment of ORF2) induces premature termination of transcription that is consistent with the effect of ORF2. |
306 | Which is the gene mutated in type 1 neurofibromatosis? | NF1 gene, encoding neurofibromin 1 | [10712197, 9190537, 8845843, 11257108, 16861979, 17019046, 17295913, 17209131, 8699317, 21354044, 20442305, 9668168, 8264648, 10874316, 10973261, 23578956, 18196300, 15770836, 17564507, 7485153, 12695655, 8528106, 9326316, 16741618, 17573495] | 413 | Two forms of neurofibromatosis, type 1 (NF1) and type 2 (NF2) are connected with genes localized on chromosomes 17 and 22, respectively. The genes that are inactivated in neurofibromatosis code for the proteins neurofibromine and merline, respectively. Since inactivation leads to neoplasia, they are called tumour suppressor genes. Neurofibromine shows resemblances to proteins that serve to inactivate oncogenes. Merline has a relationship with proteins that connect the cytoskeleton and the cell membrane. The precise function of the proteins is still unknown. The NF1 gene is characterized by extraordinarily high sensitivity to mutation; half the NF1 patients have not inherited the disease. In the familial form of neurofibromatosis, a mutated gene is inherited and the normal allele in the tumour is inactivated, making tumour growth possible. In the sporadic form of neurofibromatosis, both normal alleles are inactivated locally in the tissue so that a tumour develops in that place. CpG dinucleotides provide hotspots for transitional mutations in a variety of genes, some leading to genetic diseases in humans. Although this phenomenon is attributed to cytosine methylation at such sites, direct and specific observations of CpG methylation at the sites of recurrent mutations are lacking. We have used a bisulfite genomic sequencing method to analyze DNA methylation within three representative exons from the neurofibromatosis type 1 (NF1) gene, well recognized for its high frequency of spontaneous mutations. We observed that the cytosine methylation within NF1 exons 28, 29, and 31 is restricted to CpG dinucleotides, including the CpG dinucleotide present at the site of the recurrent NF1 mutation (C5839T; also referred to as R1947X). At several sites, clone-specific methylation differences were also observed. Our results provide experimental evidence for the hypothesis that methylatable CpGs in the NF1 gene contribute to spontaneous germline mutations associated with this gene, by showing that DNA methylation does occur at all CpGs contained within these representative NF1 exons. As well, the DNA methylation seen at the common mutation site in exon 31 may explain why this site is frequently mutated. Methylation-dependent mutagenesis may also provide a basis for some somatic (second hit) mutations which disable the normal allele and result in the development of NF1 associated symptoms. The tumorigenesis of sporadic endocrine tumors is still not fully understood. It is well known that patients with von Recklinghausen syndrome (NF-1) (OMIM 162200) carrying NF1 germline mutations are predisposed to endocrine tumors including pheochromocytomas and duodenal somatostatinomas. It is unclear, however, whether the rarely reported occurrence of pancreatic insulinomas in NF-1 patients represents a coincidental finding or whether insulinomas are a rare manifestation of the NF-1 syndrome. To determine the potential association between the NF-1 syndrome and pancreatic endocrine tumors, we analyzed a NF-1 patient with a well-differentiated pancreatic endocrine carcinoma for NF1 mutation, allelic loss of the NF1 gene and its expression in peripheral blood and tumor cells. The germline mutation c. 499 del TGTT known in the family was confirmed by polymerase chain reaction (PCR) and direct sequencing of exon 4 in DNA extracted from peripheral blood. Loss of heterozygosity (LOH) analysis of the NF1 gene was carried out using 3 intragenic microsatellite markers on 17q11.2. RNA expression was examined by reverse transcription and a consecutive PCR spanning intron 3 of the NF1 gene including the mutated site in exon 4. Immunohistochemistry was used to analyze NF-1 protein expression. Mutation analysis of peripheral blood leukocytes confirmed the 4 base pair deletion in exon 4 starting at codon 167 (499 del TGTT). LOH analysis of tumor tissue revealed retention of both NF1 alleles. While reverse transcriptase-PCR of peripheral blood showed bi-allelic expression of both the wild-type NF1 and the mutated form, reverse transcriptase-PCR of tumor extracts demonstrated expression of the mutated but not the wild-type NF1 allele. Additionally, neurofibromin, the NF1 gene product, was absent in the tumor tissue of the NF-1 patient. These results show that the wild-type NF1 transcrips and protein are reduced, in the reported insulinoma, supposedly by epigenetic mechanisms. This provides strong evidence that there is a relationship between von Recklinghausen disease and the patient's insulinoma. In this line, insulinomas may be viewed as a rare manifestation of the NF-1 syndrome. Furthermore, the NF1 gene must be considered as a candidate tumor suppressor gene for sporadic insulinomas and probably other pancreatic endocrine tumors. BACKGROUND: Neurofibromatosis type 1 (NF1) is a neurocutaneous disorder resulting in the growth of a variety of tumours, and is inherited in an autosomal dominant pattern. Gastrointestinal stromal tumours (GISTs) are mesenchymal tumours that commonly harbour oncogenic mutations in KIT or PDGFRA and are thought to arise from the interstitial cells of Cajal (ICC; the pacemaker cells of the gut). AIM: To characterise two patients with NF1 and GISTs. METHODS: Two patients were genotyped for germline mutations in NF1. GISTs from both patients were genotyped for somatic mutations in KIT and PDGFRA. Loss of heterozygosity (LOH) of NF1 in one GIST was assessed by genotyping seven microsatellite markers spanning 2.39 Mb of the NF1 locus in the tumour and in genomic DNA. The known germline mutation in NF1 was confirmed in GIST DNA by sequencing. The copy number of the mutated NF1 allele was determined by multiplex ligand-dependent probe amplification. RESULTS: GISTs from both patients were of wild type for mutations in KIT and PDGFRA. In the GIST with adequate DNA, all seven markers were informative and showed LOH at the NF1 locus; sequencing of NF1 from that GIST showed no wild-type sequence, suggesting that it was lost in the tumour. Multiplex ligand-dependent probe amplification analysis showed that two copies of all NF1 exons were present. CONCLUSIONS: This is the first evidence of mitotic recombination resulting in a reduction to homozygosity of a germline NF1 mutation in an NF1-associated GIST. We hypothesise that the LOH of NF1 and lack of KIT and PDGFRA mutations are evidence of an alternative pathogenesis in NF1-associated GISTs. The proto-oncogene ras is an essential gene for the growth and the differentiation for various types of cells. Ras, ras gene product, is a GTP binding protein which controls the signal transduction by GTP hydrolysis. The ras gene is frequently activated by point mutations in various types of human cancers, which results in a decrease in the GTPase activity of its product. A GTPase-activating protein p120 (p120GAP) was identified as a factor which stimulates the GTPase of normal ras gene product p21 but not of the mutated. An NF1 gene was identified as a gene whose loss of function causes an onset of human disorder, neurofibromatosis type I. The NF1 gene encodes a protein which contains a region with a similarity to the catalytic domain of p120GAP. We recently purified a novel Ras GAP whose molecular weight and immunogenecity are different from those of p120GAP and NF1. We named the novel mammalian Ras GAP as Gap1m. Isolation and sequencing of Gap1m cDNA revealed that Gap1m is indeed a novel Ras GAP. We also succeeded in isolation of another novel Ras GAP gene, GapIII/Gap1IP4BP, which is closely related to Gap1m. Recently, it is shown that GapIII/Gap1IP4BP binds inositol-tetrakis phosphate compounds. The overview of these Ras GAP molecules is described. Lysine 1423 of neurofibromin (neurofibromatosis type I gene product [NF1]) plays a crucial role in the function of NF1. Mutations of this lysine were detected in samples from a neurofibromatosis patient as well as from cancer patients. To further understand the significance of this residue, we have mutated it to all possible amino acids. Functional assays using yeast ira complementation have revealed that lysine is the only amino acid that produced functional NF1. Quantitative analyses of different mutant proteins have suggested that their GTPase-activating protein (GAP) activity is drastically reduced as a result of a decrease in their Ras affinity. Such a requirement for a specific residue is not observed in the case of other conserved residues within the GAP-related domain. We also report that another residue, phenylalanine 1434, plays an important role in NF1 function. This was first indicated by the finding that defective NF1s due to an alteration of lysine 1423 to other amino acids can be rescued by a second site intragenic mutation at residue 1434. The mutation partially restored GAP activity in the lysine mutant. When the mutation phenylalanine 1434 to serine was introduced into a wild-type NF1 protein, the resulting protein acquired the ability to suppress activated phenotypes of RAS2Val-19 cells. This suppression, however, does not involve Ras interaction, since the phenylalanine mutant does not stimulate the intrinsic GTPase activity of RAS2Val-19 protein and does not have an increased affinity for Ras proteins. Tumors of the central nervous system are the most frequent solid tumors in childhood. With 30-40% of this heterogenous group, low-grade astrocytomas represent the most common subtype. Neurofibromatosis type 1 (NF1) is strongly associated with the development of pilocytic astrocytoma (PA), frequently appearing as optic glioma. Neurofibromatosis 1 gene (NF1 ) fulfills the criteria of a tumor suppressor gene and is deleted or mutated heterozygously in patients with NF1. This suggests an involvement in the development of PA. To clarify whether silencing of NF1 by promoter methylation plays a role in PA and especially in optic glioma, the authors investigated the methylation status in 30 PA, 6 of which had optic glioma. However, no methylation was found at the NF1 promoter region in PA. To rule out that silencing of NF1 by promoter methylation is restricted to higher-grade astrocytomas, 15 pediatric WHO II degree and IV degree astrocytomas were analyzed: 12 astrocytomas II and 3 glioblastomas displayed no NF1 promoter methylation. The authors conclude that NF1 silencing by methylation plays no role in low-grade astrocytoma. Neurofibromatosis type 1 (NF1) is the most frequent neurocutaneous disorder with autosomal dominant inheritance. Phenotype variability is high ranging from merely several café-au-lait spots to malignant peripheral nerve sheath tumors or severe disfigurement through plexiform neurofibromas. Identification of genetic factors that modify the NF1 phenotype would contribute to the understanding of NF1 pathophysiology and improve patient counselling. As even monozygotic (MZ) twins with NF1 may differ phenotypically, we wondered whether these variations might be inherited in a non-Mendelian fashion. Mitochondrial DNA (mtDNA) is inherited extrachromosomally through the cytoplasm of the oocyte and often harbours heteroplasmic sequence variations. At the time of blastomere separation, these variants may be skewedly distributed and effect phenotypic differences. Because of their co-localization with the tumor suppressor protein neurofibromin, which is mutated in NF1, mitochondria were particular attractive candidates for investigation. MtDNA was extracted from nucleated blood cells of four pairs of discordant MZ twins with NF1 and from cutaneous neurofibromas of one twin pair. We sequenced the entire mitochondrial genome and determined the state of heteroplasmy by investigating a microsatellite region of the mitochondrial D-loop (D310-tract). The clinical diagnosis was confirmed in all patients by detection of pathogenic mutations in the NF1 gene. Monozygosity was verified by genotyping. However, we did not detect evidence for mtDNA sequence differences or for different degrees of heteroplasmy between individuals of the same twin pair. The phenotypic discordance of MZ twins with NF1 cannot be explained by skewed distribution of mtDNA mutations or polymorphisms. Neurofibromatosis type 1 (NF1) is caused by deletions, insertions, translocations, and point mutations in the NF1 gene, which spans 350 kb on the long arm of human chromosome 17. Although several point mutations have been described, large molecular abnormalities have rarely been characterized in detail. We describe here the molecular breakpoints of a 12-kb deletion of the NF1 gene, which is responsible for the NF1 phenotype in a kindred with two children affected because of germline mosaicism in the unaffected father, who has the mutation in 10% of his spermatozoa. The mutation spans introns 31-39, removing 12,021 nt and inserting 30 bp, of which 19 bp are a direct repetition of a sequence located in intron 31, just 4 bp before the 5' breakpoint. The 5' and 3' breakpoints contain the sequence TATTTTA, which could be involved in the generation of the deletion. The most plausible explanation for the mechanism involved in the generation of this 12-kb deletion is homologous/nonhomologous recombination. Since sperm of the father does not contain the corresponding insertion of the 12-kb deleted sequence, this deletion could have occurred within the NF1 chromosome through loop formation. RNA from lymphocytes of one of the NF1 patients showed similar levels of the mutated and normal transcripts, suggesting that the NF1-mRNA from mutations causing frame shifts of the reading frame or stop codons in this gene is not degraded during its processing. The mutation was not detected in fresh lymphocytes from the unaffected father by PCR analysis, supporting the case for true germ-line mosaicism. Neurofibromatosis type 1 (NF1) gene is a tumor suppressor gene, and the NF1 gene product, neurofibromin, can downregulate the N-ras gene. Because the N-ras gene is often mutated in acute myelogenous leukemia (AML), we wondered if the NF1 gene might be mutated in those AML samples not having N-ras mutations. We investigated the mutational status of the N-ras gene and the FLR exon of codons 1371-1423 of the open reading frame of the full-length NF1 cDNA, which has a strong homology with the mammalian ras GTPase-activating protein (GAP), especially for a stretch of three consecutive amino acids (F, L, R), by single-strand conformation polymorphism analysis and direct sequencing in samples from patients with AML. Of 48 AML patients, 10 (21%) had point (missense) mutations of the N-ras gene involving codons 12, 13 and 61. However, mutations in the FLR exon of the NF1 gene were not detected in any of the AML samples. We also examined the difference of clinical response to induction therapy between AML patients with and without N-ras mutation. A significantly lower rate of complete remission was noted in individuals with N-ras gene mutations. These results suggest that mutation of the NF1 gene, at least in the FLR exon, is very rare in AML and the NF1 gene probably is not a functional complement of the N-ras gene mutation. The presence of N-ras gene mutation may be associated with a lower clinical response to antileukemic therapy. Neurofibroma is a benign tumor that arises from small or large nerves. This neoplastic lesion is a common feature of neurofibromatosis type 1 (NF1), one of the most common autosomal dominant disorders. The NF1 gene codes for a protein called "neurofibromin." It possesses a region that shares a high homology with the family of GTPase-activating proteins, which are negative regulators of RAS function and thereby control cell growth and differentiation. The evidence points to the NF1 gene being a tumor-suppressor gene. NF1 patients also have an increased incidence of certain malignant tumors that are believed to follow the "two hit" hypothesis, with one allele constitutionally inactivated and the other somatically mutated. Recently, somatic loss of heterozygosity (LOH) has been described for neurofibromas, and mutations in both copies of the NF1 gene have been reported for a dermal neurofibroma. The aim of our study was the analysis of the NF1 locus in benign neurofibromas in NF1 patients. We performed LOH analysis on 60 neurofibromas belonging to 17 patients, 9 of them with family history of the disease and 8 of them sporadic. We have analyzed five intragenic NF1 markers and six extragenic markers, and we have found LOH in 25% of the neurofibromas (corresponding to 53% of the patients). In addition, we found that in the neurofibromas of patients from familial cases the deletions occurred in the allele that is not transmitted with the disease, indicating that both copies of the NF1 gene were inactivated in these tumors. Therefore, the recent reports mentioned above, together with our findings, strongly support the double inactivation of the NF1 gene in benign neurofibromas. BACKGROUND: Neurofibromatosis type 1 (NF1) is a common disorder of dysregulated tissue growth secondary to mutations in the tumor suppressor gene NF1. Pulmonary arterial hypertension (PAH) in patients with NF1 is hypothesized to be secondary to an underlying vasculopathy. METHODS: We describe the entity we term NF1-associated PAH (NF1-PAH) in four new patients and update the data on four previously published reports of patients with PAH and NF1. We performed genetic testing of the bone morphogenic protein receptor 2 (BMPR2) gene, which mutated in 70% of patients with familial PAH and approximately 25% of patients with idiopathic PAH. We report, for the first time, pathologic findings in the autopsy-obtained lung of one patient with NF1-PAH. RESULTS: Patients with NF1-PAH have a generally poor long-term prognosis. In four patients, we observed the mosaic pattern of lung attenuation on a CT scan of the chest, a radiographic finding that can be consistent with an underlying vasculopathy. No mutations or rearrangements in the BMPR2 gene were found. We observed complex plexiform lesions in the one available autopsy specimen. Similar lesions are a hallmark of plexogenic pulmonary arteriopathy and are associated with several severe types of PAH. (Plexiform lesions should not be confused with plexiform neurofibromas, which are distinctive tumors seen in NF1.) CONCLUSIONS: Our findings suggest that NF1 should be considered as being "associated with PAH as outlined in the Revised Clinical Classification of Pulmonary Hypertension. Understanding the mechanism of PAH in NF1 may inform the pathogenesis of PAH, NF1-PAH itself, and other NF1-associated vasculopathies. The pulmonary vasculature should now be included among the arterial beds affected by NF1 vasculopathy. |
307 | List receptors of the drug Cilengitide | Cilengitide binds αvβ3 and αvβ5 integrins. It inhibits attachment and invasion of malignant cells. Thus, cilengitide is being tested for treatment of cancer patients. | [22517378, 21269250, 24433287, 18779539, 24328341, 18838556, 21739168, 22582818, 12154028, 25486381, 23948974, 12706360, 16729916, 23060541, 21049281, 20820929, 24595274, 21914576, 23152080, 17896915, 21512659, 17693653, 21827415, 19929817, 18981465, 23728220, 23229276, 20029421, 20648558] | 414 | Cilengitide, a cyclic RGD pentapeptide, is currently in clinical phase III for treatment of glioblastomas and in phase II for several other tumors. This drug is the first anti-angiogenic small molecule targeting the integrins αvβ3, αvβ5 and αvβ1. It was developed by us in the early 90s by a novel procedure, the spatial screening. This strategy resulted in c(RGDfV), the first superactive αvβ3 inhibitor (100 to 1000 times increased activity over the linear reference peptides), which in addition exhibited high selectivity against the platelet receptor αIIbβ3. This cyclic peptide was later modified by N-methylation of one peptide bond to yield an even greater antagonistic activity in c(RGDf(NMe)V). This peptide was then dubbed Cilengitide and is currently developed as drug by the company Merck-Serono (Germany). This article describes the chemical development of Cilengitide, the biochemical background of its activity and a short review about the present clinical trials. The positive anti-angiogenic effects in cancer treatment can be further increased by combination with "classical" anti-cancer therapies. Several clinical trials in this direction are under investigation. The RGD cyclic pentapetide, cilengitide, is a selective inhibitor of αvβ3 and αvβ5 integrins and was developed for antiangiogenic therapy. Since cilengitide interacts with platelet αIIbβ3 and platelets express αv integrins, the effect of cilengitide on platelet pro-coagulative response and adhesion is of interest. Flow-based adhesion assays were performed to evaluate platelet adhesion and rolling on von Willebrand factor (vWf), on fibrinogen and on human umbilical vein endothelial cells (HUVECs). Flow cytometry was used to detect platelet activation (PAC1) and secretion (CD62P) by cilengitide and light transmission aggregometry was used to detect cilengitide-dependent platelet aggregation. Cilengitide inhibited platelet adhesion to fibrinogen at concentrations above 250 µM [which is the Cmax in human studies] and adhesion to vWf and HUVECs at higher concentrations under physiologic flow conditions. Platelet aggregation was already impaired at cilengitide concentrations >10 µM. Activation of αIIbβ3 integrin was inhibited by 250 µM cilengitide, whereas platelet secretion was unaffected by cilengitide. No evidence of cilengitide-induced platelet activation was found at all tested concentrations (0.01-1500 µM). At higher concentrations, platelet activation was inhibited, predominantly due to αIIbβ3 inhibition. Growth factor receptors and angiogenesis play major roles in the oncogenesis of gliomas. Over the last several years, several noncytotoxic molecular targeted therapies have been developed against growth factor receptors and tumor angiogenesis. In gliomas, two main anti-growth factor receptor strategies have been evaluated in phase I/II clinical trials: (a) small molecule tyrosine kinase inhibitors (TKIs) and (b) monoclonal antibodies that target growth factors or growth factor receptors other than vascular endothelial growth factor (VEGF). Up to now, few glioma patients have responded to small TKIs (0%-14%) or monoclonal antibodies (three case reports) delivered as a single agent. Greater doses, combined therapies, as well as the identification of molecular biomarkers predictive of response and resistance are important in order to optimize drug delivery and improve efficacy. Antiangiogenic therapies are promising for the treatment of gliomas. Thalidomide and metronomic chemotherapy were the first antiangiogenic strategies evaluated, but they have shown only modest activity. Recent studies of bevacizumab, an anti-VEGF antibody, and irinotecan, a topoisomerase I inhibitor, have demonstrated a high response rate, suggesting that targeted antiangiogenic therapies may play a significant role in the management of high-grade gliomas in the future. However, the toxicity profiles of these agents are not fully defined and the radiological evaluation of possible tumor response is challenging. Clinical evaluation of several VEGF receptor TKIs is currently ongoing; one of these inhibitors, cediranib, has already demonstrated interesting activity as a single agent. The integrin inhibitor cilengitide represents another promising strategy. Cilengitide is an RGD-peptide of sequence cyclo[RGDfNMeV] that was was developed as a highly active and selective ligand for the αvβ3 and αvβ5 integrin receptors. We describe the synthesis of three analogues of this peptide in which the N-Me group has been replaced by N-oligoethylene glycol (N-OEG) chains of increasing size: namely N-OEG2, N-OEG11, and N-OEG23, which are respectively composed of 2, 11, and 23 ethylene oxide monomer units. The different N-OEG cyclopeptides and the original peptide were compared with respect to lipophilicity and biological activity. The N-OEG2 analogue was straightforward to synthesize in solid phase using an Fmoc-N-OEG2 building block. The syntheses of the N-OEG11 and N-OEG23 cyclopeptides are hampered by the increased steric hindrance of the N-substituent, and could only be achieved by segment coupling, which takes place with epimerization and thus requires extensive product purification. All the N-OEG analogues were found to be more hydrophobic than the parent peptide, and their hydrophobicity was systematically enhanced upon increasing the length of the OEG chain. The N-OEG2 cyclopeptide displayed the same capacity as Cilengitide to inhibit the integrin-mediated adhesion of HUVEC endothelial, DAOY gliobastoma, and HT-29 colon cancer cells to their ligands vitronectin and fibrinogen. The N-OEG11 and N-OEG23 analogues also inhibited cell adhesion to these immobilized ligands, but their IC50 values dropped by 1 order of magnitude with respect to the parent peptide. These results indicate that replacement of the backbone N-Me group of Cilengitide by a short N-OEG chain provides a more lipophilic analogue with a similar biological activity. Upon increasing the size of the N-OEG chain, liophilicity is enhanced, but synthetic yields drop and the longer polymer chains may impede targeted binding. Aza-peptides are obtained by replacement of the α-C-atom of one or more amino acids by a nitrogen atom in a peptide sequence. Introduction of aza-residues into peptide sequences may result in unique structural and pharmacological properties, such that aza-scanning may be used to probe structure-activity relationships. In this study, a general approach for the synthesis of cyclic aza-peptides was developed by modification of strategies for linear aza-peptide synthesis and applied in the preparation of cyclic aza-pentapeptides containing the RGD (Arg-Gly-Asp) sequence. Aza-amino acid scanning was performed on the cyclic RGD-peptide Cilengitide, cyclo[R-G-D-f-N(Me)V] 1, and its parent peptide cyclo(R-G-D-f-V) 2, potent antagonists of the αvβ3, αvβ5, and α5β1 integrin receptors, which play important roles in human tumor metastasis and tumor-induced angiogenesis. Although incorporation of the aza-residues resulted generally in a loss of binding affinity, cyclic aza-peptides containing aza-glycine retained nanomolar activity toward the αvβ3 receptor. Molecules that target and inhibit αvβ3, αvβ5, and α5β1 integrins have generated great interest because of the role of these receptors in mediating angiogenesis and metastasis. Attempts to increase the binding affinity and hence the efficacy of integrin inhibitors by dimerization have been marginally effective. In the present work, we achieved this goal by using oxime-based chemical conjugation to synthesize dimers of integrin-binding cystine knot (knottin) miniproteins with low-picomolar binding affinity to tumor cells. A non-natural amino acid containing an aminooxy side chain was introduced at different locations within a knottin monomer and reacted with dialdehyde-containing cross-linkers of different lengths to create knottin dimers with varying molecular topologies. Dimers cross-linked through an aminooxy functional group located near the middle of the protein exhibited higher apparent binding affinity to integrin-expressing tumor cells compared with dimers cross-linked through an aminooxy group near the C-terminus. In contrast, the cross-linker length had no effect on the integrin binding affinity. A chemical-based dimerization strategy was critical, as knottin dimers created through genetic fusion to a bivalent antibody domain exhibited only modest improvement (less than 5-fold) in tumor cell binding relative to the knottin monomer. The best oxime-conjugated knottin dimer achieved an unprecedented 150-fold increase in apparent binding affinity over the knottin monomer. Also, this dimer bound 3650-fold stronger and inhibited tumor cell migration and proliferation compared with cilengitide, an integrin-targeting peptidomimetic that performed poorly in recent clinical trials, suggesting promise for further therapeutic development. Two randomized trials demonstrated an improvement in survival with docetaxel-based chemotherapy for patients with metastatic, androgen-independent prostate disease. However, the effect of current therapy is suboptimal in that it is complicated by toxicities and has no curative potential. Cilengitide (EMD121974; NSC 707544), is a potent selective alphavbeta3 and alphavbeta5 integrin antagonist. Integrins are cell surface receptors that mediate a variety of cell activities including endothelial cell proliferation and migration. Blocking the ligation of integrins by antagonists promotes apoptosis of proliferative angiogenic cells, thereby suspending new blood vessel formation, which is essential for the growth of malignant disease. In prostate cancer specifically, integrins are known to be involved in metastases with differential expression on tumor cells. Tumors and vascular endothelial cells produce factors, such as vascular endothelial growth factor and basic fibroblast growth factor, that promote neovascularization, which has been implicated in prostate cancer progression. Cilengitide has been shown to inhibit alphavbeta3- and alphavbeta5-mediated cell adhesion and block in vitro endothelial cell migration. In vivo experiments demonstrated that cilengitide inhibited cytokine-induced basic fibroblast growth factor- and vascular endothelial growth factor-mediated angiogenesis in a dose-dependent manner. Cilengitide also inhibited tumor growth in various in vivo systems. Two Cancer Therapy Evaluation Program-sponsored, multicenter, phase II trials are designed to evaluate the safety and efficacy of this agent in patients with androgen-independent prostate cancer. National Cancer Institute trial 6735 is evaluating cilengitide at 2000 mg in patients with nonmetastatic androgen-independent prostate cancer, and National Cancer Institute trial 6372 is evaluating 2 dose levels of cilengitide, 500 mg or 2000 mg, intravenously twice weekly in patients with metastatic prostate cancer. BACKGROUND: Integrins mediate invasion and angiogenesis in prostate cancer bone metastases. We conducted a phase II study of cilengitide, a selective antagonist of α(v)β(3) and α(v)β(5) integrins, in non-metastatic castration resistant prostate cancer with rising PSA. METHODS: Patients were observed for 4 weeks with PSA monitoring, and then treated with 2,000 mg IV of cilengitide twice weekly until toxicity/progression. PSA, circulating tumor cells (CTCs) and circulating endothelial cells (CECs) were monitored each cycle with imaging performed every three cycles. Primary end point was PSA decline by ≥ 50%. Secondary endpoints were safety, PSA slope, time to progression (TTP), overall survival (OS), CTCs, CECs and gene expression. RESULTS: 16 pts were enrolled; 13 were eligible with median age 65.5 years, baseline PSA 8.4 ng/mL and median Gleason sum 7. Median of three cycles was administered. Treatment was well tolerated with two grade three toxicities and no grade four toxicities. There were no PSA responses; 11 patients progressed by PSA after three cycles. Median TTP was 1.8 months and median OS has not been reached. Median pre- and on-treatment PSA slopes were 1.1 and 1.8 ng/mL/month. Baseline CTCs were detected in 1/9 patients. CTC increased (0 to 1; 2 pts), remained at 0 (2 pts) or decreased (23 to 0; 1 patient) at progression. Baseline median CEC was 26 (0-61) and at progression, 47 (15-148). Low cell counts precluded gene expression studies. CONCLUSIONS: Cilengitide was well tolerated but had no detectable clinical activity. CTCs are of questionable utility in non-metastatic prostate cancer. Malignant pleural mesothelioma (MPM) is an almost invariably fatal, asbestos-related malignancy arising from the mesothelial membrane lining the thoracic cavities. Despite some improvements in treatment, therapy is not considered curative and median survival following diagnosis is less than 1 year. Although still classed as a rare cancer, the incidence of MPM is increasing, and the limited progress in treating the disease makes the identification of new therapies a priority. As there is evidence for expression of the integrins αvβ3 and αvβ5 in MPM, there is a rationale for investigating the effects on MPM of cilengitide, a synthetic peptide inhibitor of integrin αv heterodimer with high specificity for αvβ3 and αvβ5. In mesothelial cells (MC) and 7 MPM cell lines, growth inhibition by cilengitide was associated with the expression level of its target integrins. Furthermore, cilengitide caused cell detachment and subsequent death of anoikis-sensitive cells. It also suppressed invasion of MPM cells in monolayer and three-dimensional cultures. Gene knockdown experiments indicated that these effects of cilengitide were, at least partly, due to antagonism of αvβ3 and αvβ5. Last years saw the development of anti-angiogenic strategies in the treatment of cancers. Cilengitide (EMD121974; Merck KGaA, Darmstadt, Germany) is a new drug targeting αvβ3 and αvβ5 integrins thanks to a specific peptide called RGD sequence. Cilengitide acts in correlations between endothelial cells, tumor cells and extracellular matrix. The promising results obtained with Cilengitide in vitro, used alone or in combination with cytotoxic chemotherapy or ionizing radiations, could give many hopes especially for the treatment of cerebral tumors. Clinical trials are nowadays ongoing in this indication. The aim of this review is to take stock of the situation on the mechanisms of action of the integrin inhibitor Cilengitide (EMD121974; Merck KGaA, Darmstadt, Germany) with a focus on the first pre-clinical and clinical results. Isolated limb perfusion (ILP) with melphalan and tumor necrosis factor (TNF)-α is used to treat bulky, locally advanced melanoma and sarcoma. However, TNF toxicity suggests a need for better-tolerated drugs. Cilengitide (EMD 121974), a novel cyclic inhibitor of alpha-V integrins, has both anti-angiogenic and direct anti-tumor effects and is a possible alternative to TNF in ILP. In this study, rats bearing a hind limb soft tissue sarcoma underwent ILP using different combinations of melphalan, TNF and cilengitide in the perfusate. Further groups had intra-peritoneal (i.p.) injections of cilengitide or saline 2 hr before and 3 hr after ILP. A 77% response rate (RR) was seen in animals treated i.p. with cilengitide and perfused with melphalan plus cilengitide. The RR was 85% in animals treated i.p. with cilengitide and ILP using melphalan plus both TNF and cilengitide. Both RRs were significantly greater than those seen with melphalan or cilengitide alone. Histopathology showed that high RRs were accompanied by disruption of tumor vascular endothelium and tumor necrosis. Compared with ILP using melphalan alone, the addition of cilengitide resulted in a three to sevenfold increase in melphalan concentration in tumor but not in muscle in the perfused limb. Supportive in vitro studies indicate that cilengitide both inhibits tumor cell attachment and increases endothelial permeability. Since cilengitide has low toxicity, these data suggest the agent is a good alternative to TNF in the ILP setting. Development of molecular devices endowed with tumor-targeting functions and carrying cytotoxic components should enable the specific delivery of chemotherapeutics to malignant tissues, thus increasing their local efficacy while limiting their peripheral toxicity. Such molecular vectors can pave the way for the development of new classes of therapeutics, fighting against protagonists of neoplastic development. In line with this concept, peptide ligands containing the Arginine-Glycine-Aspartate (RGD) triad, which display a strong affinity and selectivity to the alpha(V)beta(3) integrin, have been developed to target the tumor-associated cells expressing the alpha (V)beta (3) receptors. Among the validated ligands, the leader compound is the cyclic pentapeptide c[-RGDf(NMe)V-] (Cilengitide) developed by kessler et al. (J. Med. Chem., 1999, 42, 3033-3040). This compound has entered phase II clinical trials as an anti-angiogenic agent. Further studies have been directed to develop molecular conjugates of the parent c[-RGDfK-] with conventional chemotherapeutics or with labels for non-invasive imaging technologies. More recently, multimeric RGD containing compounds have been exploited to improve the targeting potential as well as cell-membrane breaching, through receptor-mediated endocytosis. The latter have been constructed on various scaffolds (polylysines or polyglutamates, liposomes, nanoparticles...). Our group has developed a chemical system combining all these properties where multivalent RGD targeting functions are associated with functional molecules through a cyclopeptide template. The latter represents a relevant non-viral vector for tumor targeting, imaging and therapy. This review describes the considerations for the design of the diverse RGD ligands developed so far and reports an overview of the main applications of these structures in cancer research. The purpose of this study was the assessment of the feasibility of dynamic positron emission tomography (PET) studies with fluorine-18 fluorodeoxyglucose ((18)F-FDG) to quantify effects of the cyclic Arg-Gly-Asp peptide cilengitide, which targets the ανβ 3 and ανβ 5 integrin receptors in rats with breast cancer bone metastases. Rats were inoculated with MDA-MB-231 breast cancer cells, followed by the development of lytic lesions in the hind leg. Rats with lytic lesions were treated with cilengitide five times weekly on a continuous basis from days 30 to 55 after tumor cell inoculation. Dynamic PET studies with (18)F-FDG were performed in untreated (n=9), controlled (n=4) and treated rats (n=6). The data were assessed using learning-machine two-tissue compartmental analysis. The (18)F-FDG kinetic parameters obtained by two-tissue compartmental model learning-machine showed significant differences when individual parameters were compared between the control group and treated animals. Quantitative assessment of the tracer kinetics and the application of classification analysis to the data provided us with evidence to identify those tumors that demonstrated effect of cilengitide treatment. The transport rate K1 and the phosphorylation rate k3 were significantly different (P=0.033 and 0.038, respectively). Classification analysis based on support vector machines ranking feature elimination of the combination of PET parameters revealed an overall accuracy of 80.0% between treated animals and the control group. We were able to identify 83.3% treated animals compared with the control group based on k2 and VB. In conclusion, the results revealed that cilengitide treatment of experimental breast cancer bone metastases had a significant therapeutic impact on (18)F-FDG kinetics. The tumor environment is critical for tumor maintenance and progression. Integrins are a large family of cell surface receptors mediating the interaction of tumor cells with their microenvironment and play important roles in glioma biology, including migration, invasion, angiogenesis and tumor stem cell anchorage. Here, we review preclinical and clinical data on integrin inhibition in malignant gliomas. Various pharmacological approaches to the modulation of integrin signaling have been explored including antibodies and peptide-based agents. Cilengitide, a cyclic RGD-mimetic peptide of αvβ3 and αvβ5 integrins is in advanced clinical development in glioblastoma. Cilengitide had only limited activity as a single agent in glioblastoma, but, when added to standard radiochemotherapy, appeared to prolong progression-free and overall survival in patients with newly diagnosed glioblastomas and methylation of the promoter of the O⁶ methylguanine methyltransferase (MGMT) gene. MGMT gene promoter methylation in turn predicts benefit from alkylating chemotherapy. A phase III randomized clinical trial in conjunction with standard radiochemotherapy in newly diagnosed glioblastoma patients with MGMT gene promoter methylation has recently completed accrual (EORTC 26071-22072). A companion trial explores a dose-escalated regimen of cilengitide added to radiotherapy plus temozolomide in patients without MGMT gene promoter methylation. Promising results in these trials would probably result in a broader interest in integrins as targets for glioma therapy and hopefully the development of a broader panel of anti-integrin agents. Integrins are a large family of dimeric receptors composed by alpha and beta subunits that, once bound to extra-cellular matrix (ECM) proteins, regulate a variety of cellular processes such as cell motility, migration, and proliferation. The integrins transduce signals from inside-out and outside-in the cell, thus representing the cellular link to the external environment. For these properties, integrin activation has been involved in pathological processes like tumor growth and metastasis formation. Recent advances in the elucidation of the crystallographic structures of the alphavbeta3 and alphaIIbeta3 integrins are promoting studies focused to the search of small molecule antagonists that can block the integrin binding to ECM and inhibit the biological effects exerted by these receptors. In this review we will focus on small molecule antagonists of alphavbeta3 and alphavbeta5 integrin as tools for cancer therapy while other integrins will only be briefly mentioned. Cilengitide (cyclic peptidic alphavbeta3 and alphavbeta5 antagonist) is currently in clinical trials for anti cancer therapy. Combination of integrin alphavbeta3 antagonists and other traditional therapeutic approaches may represent a future strategy to inhibit tumor growth and metastasis spreading. The prognosis of children with high-grade glioma or high-risk neuroblastoma remains poor. Cilengitide is a selective antagonist of αvβ3 and αvβ5 integrins, which are involved in tumor growth and development of metastasis. We have evaluated the effects of cilengitide on pediatric glioma and neuroblastoma cell lines for the first time. Expression levels of αvβ3 and αvβ5 were determined by flow cytometry in three neuroblastoma and five pediatric glioma cell lines compared with adult U87-MG before and after irradiation. Cell detachment, cytotoxicity, and cell growth under nonadhesive conditions were measured using the MTS assay. Cell death and apoptosis were assessed by annexin-V/propidium iodide staining. The varying αvβ3 and αvβ5 expression levels were unrelated to tumor grade. Irrespective of the αvβ5 expression level, the pediatric cells expressing αvβ3 were dose dependently sensitive to cilengitide. UW479 cells expressed only αvβ5 integrin and were not sensitive to cilengitide, suggesting that cilengitide's action largely depends on αvβ3 inhibition. Cell detachment resulted in a higher cytotoxicity in pediatric glioma compared with U87-MG cells, which seem able to grow despite the significant cilengitide-induced cell detachment. Growth kinetics on polyHEMA showed that only pediatric glioma cells were sensitive to anoikis and so died after cilengitide-induced detachment. Furthermore, irradiation of glioma cells increased αvβ3 expression slightly but not cilengitide sensitivity. Cilengitide's action on glioma and neuroblastoma cells appears to be dependent on αvβ3 expression and sensitivity to anoikis. Cilengitide is able to target pediatric glioma and neuroblastoma cells in vitro directly and efficiently. Tumor context could validate these promising observations. PURPOSE: Aim of this study was to investigate the specific treatment effects of inhibiting αvβ3/αvβ5 integrins by cilengitide in an animal model of breast cancer bone metastases using dynamic (18)F-FDG PET and gene expression analysis. METHODS: For this purpose, nude rats bearing bone metastases were treated with cilengitide, a small molecule inhibitor of αvβ3 and αvβ5 integrins, from day 30 to 55 after tumor cell inoculation of MDA-MB-231 breast cancer cells (25 mg/kg, 5 days per week; n = 8 rats) and compared to control rats (n = 8). Dynamic (18)F-FDG PET data were assessed at days 30, 35 and 55 after tumor cell inoculation determining the vascular fraction VB and the metabolic variables k1-k4. At day 55, genome-wide mRNA expression analysis was performed to assess the treatment-specific expression changes from cilengitide-treated and control rats. RESULTS: In a longitudinal (18)F-FDG PET study, the vascular fraction VB was significantly decreased in bone metastases between days 30/35, 30/55 and 35/55, whereas the kinetic parameters k1 and k4 were significantly decreased between days 30/55 in skeletal lesions of treated animals. Gene expression analysis from bone metastases at day 55 revealed that tumor-produced integrins (αvβ5) as well as factors relevant for angiogenesis (αvβ3, VEGF, PDGF), bone resorption (PTHrP and RANKL), extracellular matrix remodeling (collagen, CD44) and bone marrow microenvironment (CXCR4) were significantly reduced upon therapy with cilengitide. CONCLUSIONS: Here, we provide evidence that cilengitide inhibits pivotal factors of all compartments of bone metastases including tumor cells, vasculature and bone microenvironment in vivo and by whole-genome transcriptome analysis. The aim of this study was to investigate the effect of inhibiting αvβ(3)/α(v) β(5) integrins by cilengitide in experimentally induced breast cancer bone metastases using noninvasive imaging techniques. For this purpose, nude rats bearing established breast cancer bone metastases were treated with cilengitide, a small molecule inhibitor of αvβ(3) and αvβ(5) integrins (75 mg/kg, five days per week; n = 12 rats) and compared to vehicle-treated control rats (n = 12). In a longitudinal study, conventional magnetic resonance imaging (MRI) and flat panel volumetric computed tomography were used to assess the volume of the soft tissue tumor and osteolysis, respectively, and dynamic contrast-enhanced (DCE-) MRI was performed to determine functional parameters of the tumor vasculature reflecting blood volume and blood vessel permeability. In rats treated with cilengitide, VCT and MRI showed that osteolytic lesions and the respective bone metastatic soft tissue tumors progressed more slowly than in vehicle-treated controls. DCE-MRI indicated a decrease in blood volume and an increase in vessel permeability and immunohistology revealed increased numbers of immature vessels in cilengitide-treated rats compared to vehicle controls. In conclusion, treatment of experimental breast cancer bone metastases with cilengitide resulted in pronounced antiresorptive and antitumor effects, suggesting that αvβ(3)/αvβ(5) inhibition may be a promising therapeutic approach for bone metastases. |
308 | Can protein coding exons originate from ALU sequences? | Yes. Intronic ALUs can evolve into exons by the activation of splice signals residing within the ALU sequence. While most ALU exons do not add or modify the coding capacity of the resulting transcript, examples have been identified of ALU exons becoming protein coding. | [15099521, 19393186, 18047649, 19324900, 12764196, 23374342, 16027113, 23303787, 17594509, 21282640, 21188497, 20803091, 18332115, 15901843, 15328599, 17204284, 20532223] | 415 | Alu exonization, which is an evolutionary pathway that creates primate-specific transcriptomic diversity, is a powerful tool for studying alternative-splicing regulation. Through bioinformatic analyses combined with experimental methodology, we identified the mutational changes needed to create functional 5' splice sites in Alu. We revealed a complex mechanism by which the sequence composition of the 5' splice site and its base pairing with the small nuclear RNA U1 govern alternative splicing. We show that in Alu-derived GC introns the strength of the base pairing between U1 snRNA and the 5' splice site controls the skipping/inclusion ratio of alternative splicing. Based on these findings, we identified 7810 Alus within the human genome that are prone to exonization. Mutations in these Alus may cause genetic disorders or contribute to human-specific protein diversity. BACKGROUND: Gene duplication and exonization of intronic transposed elements are two mechanisms that enhance genomic diversity. We examined whether there is less selection against exonization of transposed elements in duplicated genes than in single-copy genes. RESULTS: Genome-wide analysis of exonization of transposed elements revealed a higher rate of exonization within duplicated genes relative to single-copy genes. The gene for TIF-IA, an RNA polymerase I transcription initiation factor, underwent a humanoid-specific triplication, all three copies of the gene are active transcriptionally, although only one copy retains the ability to generate the TIF-IA protein. Prior to TIF-IA triplication, an Alu element was inserted into the first intron. In one of the non-protein coding copies, this Alu is exonized. We identified a single point mutation leading to exonization in one of the gene duplicates. When this mutation was introduced into the TIF-IA coding copy, exonization was activated and the level of the protein-coding mRNA was reduced substantially. A very low level of exonization was detected in normal human cells. However, this exonization was abundant in most leukemia cell lines evaluated, although the genomic sequence is unchanged in these cancerous cells compared to normal cells. CONCLUSION: The definition of the Alu element within the TIF-IA gene as an exon is restricted to certain types of cancers; the element is not exonized in normal human cells. These results further our understanding of the delicate interplay between gene duplication and alternative splicing and of the molecular evolutionary mechanisms leading to genetic innovations. This implies the existence of purifying selection against exonization in single copy genes, with duplicate genes free from such constrains. Transposable elements (TEs) are major sources of new exons in higher eukaryotes. Almost half of the human genome is derived from TEs, and many types of TEs have the potential to exonize. In this work, we conducted a large-scale analysis of human exons derived from mammalian-wide interspersed repeats (MIRs), a class of old TEs which was active prior to the radiation of placental mammals. Using exon array data of 328 MIR-derived exons and RT-PCR analysis of 39 exons in 10 tissues, we identified 15 constitutively spliced MIR exons, and 15 MIR exons with tissue-specific shift in splicing patterns. Analysis of RNAs from multiple species suggests that the splicing events of many strongly included MIR exons have been established before the divergence of primates and rodents, while a small percentage result from recent exonization during primate evolution. Interestingly, exon array data suggest substantially higher splicing activities of MIR exons when compared with exons derived from Alu elements, a class of primate-specific retrotransposons. This appears to be a universal difference between exons derived from young and old TEs, as it is also observed when comparing Alu exons to exons derived from LINE1 and LINE2, two other groups of old TEs. Together, this study significantly expands current knowledge about exonization of TEs. Our data imply that with sufficient evolutionary time, numerous new exons could evolve beyond the evolutionary intermediate state and contribute functional novelties to modern mammalian genomes. Alu repetitive elements can be inserted into mature messenger RNAs via a splicing-mediated process termed exonization. To understand the molecular basis and the regulation of the process of turning intronic Alus into new exons, we compiled and analyzed a data set of human exonized Alus. We revealed a mechanism that governs 3' splice-site selection in these exons during alternative splicing. On the basis of these findings, we identified mutations that activated the exonization of a silent intronic Alu. There are ~650,000 Alu elements in transcribed regions of the human genome. These elements contain cryptic splice sites, so they are in constant danger of aberrant incorporation into mature transcripts. Despite posing a major threat to transcriptome integrity, little is known about the molecular mechanisms preventing their inclusion. Here, we present a mechanism for protecting the human transcriptome from the aberrant exonization of transposable elements. Quantitative iCLIP data show that the RNA-binding protein hnRNP C competes with the splicing factor U2AF65 at many genuine and cryptic splice sites. Loss of hnRNP C leads to formation of previously suppressed Alu exons, which severely disrupt transcript function. Minigene experiments explain disease-associated mutations in Alu elements that hamper hnRNP C binding. Thus, by preventing U2AF65 binding to Alu elements, hnRNP C plays a critical role as a genome-wide sentinel protecting the transcriptome. The findings have important implications for human evolution and disease. Ancient Alu elements have been shown to be included in mature transcripts by point mutations that improve their 5' or 3' splice sites. We have examined requirements for exonization of a younger, disease-associated AluYa5 in intron 16 of the human ACE gene. A single G>C transversion in position -3 of the new Alu exon was insufficient for Alu exonization and a significant inclusion in mRNA was only observed when improving several potential splice donor sites in the presence of 3' CAG. Since complete Alu exonization was not achieved by optimizing traditional splicing signals, including the branch site, we tested whether auxiliary elements in AluYa5 were required for constitutive inclusion. Exonization was promoted by a SELEX-predicted heptamer in Alu consensus sequence 222-228 and point mutations in highly conserved nucleotides of this heptamer decreased Alu inclusion. In addition, we show that Alu exonization was facilitated by a subset of serine/arginine-rich (SR) proteins through activation of the optimized 3' splice site. Finally, the haplotype- and allele-specific ACE minigenes generated similar splicing patterns in both ACE-expressing and non-expressing cells, suggesting that previously reported allelic association with plasma ACE activity and cardiovascular disease is not attributable to differential splicing of introns 16 and 17. BACKGROUND: Transposed elements (TEs) have a substantial impact on mammalian evolution and are involved in numerous genetic diseases. We compared the impact of TEs on the human transcriptome and the mouse transcriptome. RESULTS: We compiled a dataset of all TEs in the human and mouse genomes, identifying 3,932,058 and 3,122,416 TEs, respectively. We than extracted TEs located within human and mouse genes and, surprisingly, we found that 60% of TEs in both human and mouse are located in intronic sequences, even though introns comprise only 24% of the human genome. All TE families in both human and mouse can exonize. TE families that are shared between human and mouse exhibit the same percentage of TE exonization in the two species, but the exonization level of Alu, a primate-specific retroelement, is significantly greater than that of other TEs within the human genome, leading to a higher level of TE exonization in human than in mouse (1,824 exons compared with 506 exons, respectively). We detected a primate-specific mechanism for intron gain, in which Alu insertion into an exon creates a new intron located in the 3' untranslated region (termed 'intronization'). Finally, the insertion of TEs into the first and last exons of a gene is more frequent in human than in mouse, leading to longer exons in human. CONCLUSION: Our findings reveal many effects of TEs on these two transcriptomes. These effects are substantially greater in human than in mouse, which is due to the presence of Alu elements in human. The Alu element has been a major source of new exons during primate evolution. Thousands of human genes contain spliced exons derived from Alu elements. However, identifying Alu exons that have acquired genuine biological functions remains a major challenge. We investigated the creation and establishment of Alu exons in human genes, using transcriptome profiles of human tissues generated by high-throughput RNA sequencing (RNA-Seq) combined with extensive RT-PCR analysis. More than 25% of Alu exons analyzed by RNA-Seq have estimated transcript inclusion levels of at least 50% in the human cerebellum, indicating widespread establishment of Alu exons in human genes. Genes encoding zinc finger transcription factors have significantly higher levels of Alu exonization. Importantly, Alu exons with high splicing activities are strongly enriched in the 5'-UTR, and two-thirds (10/15) of 5'-UTR Alu exons tested by luciferase reporter assays significantly alter mRNA translational efficiency. Mutational analysis reveals the specific molecular mechanisms by which newly created 5'-UTR Alu exons modulate translational efficiency, such as the creation or elongation of upstream ORFs that repress the translation of the primary ORFs. This study presents genomic evidence that a major functional consequence of Alu exonization is the lineage-specific evolution of translational regulation. Moreover, the preferential creation and establishment of Alu exons in zinc finger genes suggest that Alu exonization may have globally affected the evolution of primate and human transcriptomes by regulating the protein production of master transcriptional regulators in specific lineages. Recently, genome-wide association studies have identified a strong association between the ZBTB38 locus and human height. In a functional study, we detected two RT-PCR products of ZBTB38, amplified with primers in exons 7 and 8 from a chondrocyte cell line, C-28/I2. Sequencing revealed that the longer product contained an Alu segment in intron 7 of ZBTB38, which contained a potential splicing acceptor site that likely was used to generate the alternative transcript. Insertion of the Alu segment changed the consensus Kozak sequence of the ZBTB38 transcript, potentially altering translational efficiency. We performed RT-PCR using 16 tissue samples from humans and 8 tissue samples from primates to determine any tissue specificity or evolutionary conservation of the alternative splicing. Although we failed to identify any difference among the tissues, all primate samples expressed only the shorter Alu segment (lacking the transcript), suggesting that the alternative splicing event is hominid primate-specific. The majority of more than one million primate-specific Alu elements map to nonfunctional parts of introns or intergenic sequences. Once integrated, they have the potential to become exapted as functional modules, e.g., as protein-coding domains via alternative splicing. This particular process is also termed exonization and increases protein versatility. Here we investigate 153 human chromosomal loci where Alu elements were conceivably exonized. In four selected examples, we generated, with the aid of representatives of all primate infraorders, phylogenetic reconstructions of the evolutionary steps presumably leading to exonization of Alu elements. We observed a variety of possible scenarios in which Alu elements led to novel mRNA splice forms and which, like most evolutionary processes, took different courses in different lineages. Our data show that, once acquired, some exonizations were lost again in some lineages. In general, Alu exonization occurred at various time points over the evolutionary history of primate lineages, and protein-coding potential was acquired either relatively soon after integration or millions of years thereafter. The course of these paths can probably be generalized to the exonization of other elements as well. Survivin is a member of the inhibitor apoptosis family that is overexpressed in many malignancies. It has five known alternative splice forms, some of which differ in their antiapoptotic properties and expression levels in human cancers. Here we describe a novel donor splice site (DSS), 2B+32 DSS, which is used in conjunction with survivin alternative exon 2B, resulting in the inclusion of 32 additional nucleotides from intron 2 at the 3' end of this exon. Sequence analysis showed that both the classical exon 2B DSS and 2B+32 are provided by an Alu sequence, which is inserted in intron 2 downstream of a functional acceptor splice site, leading to the exonization of part of the repetitive element. Minor transcripts including the 2B+32 alternative exon, or retaining the whole intronic region comprised between exons 2B and 3, were detected in several human cell lines and in some human tissues. Survivin 2B+32 containing variants acquire a premature stop codon (PTC) and may therefore be degraded by the nonsense mediated decay pathway. The implication of these novel isoforms, as well as other PTC+ survivin variants, in the overall regulation of survivin expression is discussed. Sequence analysis of intron 2 which contains the Alu Y element was performed on different primate species in order to trace its insertion and exonization during primate evolution. Insertion of transposed elements within mammalian genes is thought to be an important contributor to mammalian evolution and speciation. Insertion of transposed elements into introns can lead to their activation as alternatively spliced cassette exons, an event called exonization. Elucidation of the evolutionary constraints that have shaped fixation of transposed elements within human and mouse protein coding genes and subsequent exonization is important for understanding of how the exonization process has affected transcriptome and proteome complexities. Here we show that exonization of transposed elements is biased towards the beginning of the coding sequence in both human and mouse genes. Analysis of single nucleotide polymorphisms (SNPs) revealed that exonization of transposed elements can be population-specific, implying that exonizations may enhance divergence and lead to speciation. SNP density analysis revealed differences between Alu and other transposed elements. Finally, we identified cases of primate-specific Alu elements that depend on RNA editing for their exonization. These results shed light on TE fixation and the exonization process within human and mouse genes. |
309 | How could U1 small nuclear RNA be used in therapeutics? | Until now, two main types of therapeutic strategies have been developed using U1 small nuclear RNA (snRNA): 1) Production of a defective, but partially functional protein, with the help of exon skipping, through modulation of pre-mRNA splicing, and 2) Correction of pathogenic effects of splice donor site mutations with the use of U1 snRNA adapted to the defective variant. | [22968481, 21326217, 20869034, 22362925, 21520335, 22454066, 22454067, 19219028] | 416 | Exon skipping has been demonstrated to be a successful strategy for the gene therapy of Duchenne muscular dystrophy (DMD): the rational being to convert severe Duchenne forms into milder Becker ones. Here, we show the selection of U1 snRNA-antisense constructs able to confer effective rescue of dystrophin synthesis in a Δ44 Duchenne genetic background, through skipping of exon 45; moreover, we demonstrate that the resulting dystrophin is able to recover timing of myogenic marker expression, to relocalize neuronal nitric oxide synthase (nNOS) and to rescue expression of miRNAs previously shown to be sensitive to the Dystrophin-nNOS-HDAC2 pathway. Becker mutations display different phenotypes, likely depending on whether the shorter protein is able to reconstitute the wide range of wild-type functions. Among them, efficient assembly of the dystrophin-associated protein complex (DAPC) and nNOS localization are important. Comparing different Becker deletions we demonstrate the correlation between the ability of the mutant dystrophin to relocalize nNOS and the expression levels of two miRNAs, miR-1 and miR29c, known to be involved in muscle homeostasis and to be controlled by the Dys-nNOS-HDAC2 pathway. The U1 small nuclear RNA (U1 snRNA) as a component of the major U2-dependent spliceosome recognizes 5' splice sites (5'ss) containing GT as the canonical dinucleotide in the intronic positions +1 and +2. The c.165+1G>T germline mutation in the 5'ss of exon 2 of the Fanconi anemia C (FANCC) gene commonly predicted to prevent correct splicing was identified in nine FA patients from three pedigrees. RT-PCR analysis of the endogenous FANCC mRNA splicing pattern of patient-derived fibroblasts revealed aberrant mRNA processing, but surprisingly also correct splicing at the TT dinucleotide, albeit with lower efficiency. This consequently resulted in low levels of correctly spliced transcript and minute levels of normal posttranslationally processed FANCD2 protein, indicating that this naturally occurring TT splicing might contribute to the milder clinical manifestations of the disease in these patients. Functional analysis of this FANCC 5'ss within splicing reporters revealed that both the noncanonical TT dinucleotide and the genomic context of FANCC were required for the residual correct splicing at this mutant 5'ss. Finally, use of lentiviral vectors as a delivery system to introduce expression cassettes for TT-adapted U1 snRNAs into primary FANCC patient fibroblasts allowed the correction of the DNA-damage-induced G2 cell-cycle arrest in these cells, thus representing an alternative transcript-targeting approach for genetic therapy of inherited splice-site mutations. A significant proportion of disease-causing mutations affect precursor-mRNA splicing, inducing skipping of the exon from the mature transcript. Using F9 exon 5, CFTR exon 12 and SMN2 exon 7 models, we characterized natural mutations associated to exon skipping in Haemophilia B, cystic fibrosis and spinal muscular atrophy (SMA), respectively, and the therapeutic splicing rescue by using U1 small nuclear RNA (snRNA). In minigene expression systems, loading of U1 snRNA by complementarity to the normal or mutated donor splice sites (5'ss) corrected the exon skipping caused by mutations at the polypyrimidine tract of the acceptor splice site, at the consensus 5'ss or at exonic regulatory elements. To improve specificity and reduce potential off-target effects, we developed U1 snRNA variants targeting non-conserved intronic sequences downstream of the 5'ss. For each gene system, we identified an exon-specific U1 snRNA (ExSpeU1) able to rescue splicing impaired by the different types of mutations. Through splicing-competent cDNA constructs, we demonstrated that the ExSpeU1-mediated splicing correction of several F9 mutations results in complete restoration of secreted functional factor IX levels. Furthermore, two ExSpeU1s for SMA improved SMN exon 7 splicing in the chromosomal context of normal cells. We propose ExSpeU1s as a novel therapeutic strategy to correct, in several human disorders, different types of splicing mutations associated with defective exon definition. Bardet-Biedl syndrome (BBS) is a multisystem disorder caused by ciliary defects. To date, mutations in 15 genes have been associated with the disease and BBS1 is most frequently affected in patients with BBS. The use of homozygosity mapping in a large consanguineous family allowed us to identify the splice donor site (SD) mutation c.479G>A in exon 5 of BBS1. Clinically affected family members show symptoms of retinitis pigmentosa (RP) but lack other primary features that would clearly support the diagnosis of BBS. In agreement with this exceptionally mild BBS1-associated phenotype, we did not detect obvious ciliary defects in patient-derived cells. SDs are bound by the U1 small nuclear RNA (U1), a process that initiates exon recognition during splicing. The mutation described herein interferes with U1 binding and induces aberrant splicing of BBS1. For a gene therapeutic approach, we have adapted the sequence of U1 to increase its complementarity to the mutated SD. Lentiviral treatment of patient-derived fibroblasts with the adapted U1 partially corrected aberrant splicing of endogenously expressed BBS1 transcripts. This therapeutic effect was dose-dependent. Our results show that the adaptation of U1 can correct pathogenic effects of splice donor site mutations and suggest a high potential for gene therapy. We report the use of the U1 snRNA as a vector for the stable expression of antisense molecules against the splice junctions of specific dystrophin exons. The single-stranded 5' terminus of U1 can be replaced by unrelated sequences as long as 50 nucleotides without affecting both the stability and the ability to assemble into snRNP particles. Effective exon skipping has been obtained for different dystrophin exons by antisense sequences against 5' and 3' splice sites alone or in combination with ESE sequences. The efficacy of these molecules has been studied both in in vitro systems and in animals. In both cases the chimeric molecules, delivered as part of lentiviral or AAV vectors (De Angelis et al. Proc Natl Acad Sci USA 99:9456-9461, 2002; Denti et al. Proc Natl Acad Sci USA 103: 3758-3763, 2006; Denti et al. Hum Gene Ther 17: 565-743, 2006; Denti et al. Hum Gene Ther 19: 601-608, 2008; Incitti et al. Mol Ther 18: 1675-1682, 2010), provided high skipping activity and efficient rescue of dystrophin synthesis. Moreover, the U1-antisense molecules, delivered to mice via systemic injection of recombinant AAV viruses, displayed body wide transduction, long-term expression, dystrophin rescue as well as morphological and functional benefit (Denti et al. Hum Gene Ther 19: 601-608, 2008). In this Chapter we report methods for producing U1-antisense expression cassettes in the backbone of lentiviral constructs and for testing their activity both in patients' derived myoblasts as well as in fibroblasts reprogrammed to muscle differentiation. Antisense-mediated splicing modulation of premessenger RNA represents a novel therapeutic strategy for several types of pathologies such as genetic disorders, cancers, and infectious diseases. Antisense oligonucleotides designed to bind to specific mRNA molecules have been actively developed for more than 20 years as a form of molecular medicine to modulate splicing patterns or inhibit protein translation. More recently, small nuclear RNA such as U7 or U1 small nuclear RNA have been used to carry antisense sequences, offering the advantage of long-term effect when delivered to cells using viral vectors. We have previously demonstrated the therapeutic potential of U7snRNA targeting dystrophin mRNA as a treatment for Duchenne muscular dystrophy. In particular, we showed that bifunctional U7 snRNAs harboring silencer motifs induce complete skipping of exon 51, and thus restore dystrophin expression in DMD patients cells to near wild-type levels. These new constructs are very promising for the optimization of therapeutic exon skipping for DMD, but also offer powerful and versatile tools to modulate pre-mRNA splicing in a wide range of applications. Here, we outline the design of these U7snRNA constructs to achieve efficient exon-skipping and describe methods to evaluate the efficacy of such U7snRNA constructs in vitro using the dystrophin gene as an example. We describe a gene silencing method that employs a mechanism of action distinct from those of antisense and RNA interference. U1 Adaptors are bifunctional oligonucleotides with a 'target domain' complementary to a site in the target gene's terminal exon and a 'U1 domain' that binds to the U1 small nuclear RNA component of the U1 small nuclear ribonucleoprotein (U1 snRNP) splicing factor. Tethering of U1 snRNP to the target pre-mRNA inhibits poly(A)-tail addition, causing degradation of that RNA species in the nucleus. U1 Adaptors can inhibit both endogenous and reporter genes in a sequence-specific manner. Comparison of U1 Adaptors with small interfering RNA (siRNA) using a genome-wide microarray analysis indicates that U1 Adaptors have limited off-target effects and no detectable adverse effects on splicing. Further, targeting the same gene either with multiple U1 Adaptors or with a U1 Adaptor and siRNA strongly enhances gene silencing. |
310 | What is the influence of patent expiry on ACE inhibitor prescribing. | Patent expiry has different effects on prescribing in different systems. It leads to decreased cost but no decreased refill compliance in countries like Sweden, Germany etc. In countries like Taiwan, where doctors profit directly from dispensing, patients are switched to ARBs which are more costly. | [16309337, 22521158, 21738055] | 417 | BACKGROUND: In order to increase price competition, government regulations focus on controlling drug costs. Drug costs after patent expiry are an area of particular interest because the substitution of branded medication with generics represents an opportunity for lowering drug costs. However, drug costs may not decrease after patent expiry, because of a lack of price competition and different national pricing systems. AIM: The aim of this study was to investigate the trends in the use of generics after patent expiry for enalapril, fluoxetine and ranitidine and the subsequent changes, if any, in the costs of these medications. METHODS: A drug-utilisation study was performed using data from a large sample of Dutch pharmacies. Both volumes (measured as defined daily doses [DDD] per 1000 population) as well as drug costs (calculated per DDD) prior to and after patent expiry were calculated. Costs per DDD were compared using trend-line analysis. In addition, the relative market shares of the different trade channels (branded, parallel imported and generic) were compared before and after patent expiry. RESULTS: The costs per DDD decreased for all three drugs and, as expected, these costs decrease more rapidly after patent expiry. Significant differences in the trend lines were found for enalapril and fluoxetine. CONCLUSIONS: Despite relatively high reimbursement prices for generics in the Netherlands, this example from the Dutch pharmaceutical market demonstrates the benefit of generic substitution for containing pharmaceutical costs, which contrasts with concerns raised by the Dutch government. |
311 | Is there evidence that tomato juice lowers cholesterol levels? | Yes, there is evidence to suggest that tomato juice (and other tomato products) can decrease cholesterol concentrations. It was shown that tomatoes inhibit cholesterol biosynthesis. | [24392102, 22098224, 17617941, 22223578, 21755327] | 418 | The hypocholesterolemic effect of tomato juice has been investigated in an intervention study with rats, along with the possible inhibition effect of bioactive tomato compounds binding to the HMGCR enzyme. Two experimental groups (n = 8 Sprague-Dawley rats) were fed ad libitum for five weeks, with water or tomato juice provided to the control and intervention groups, respectively. Total, LDL and HDL cholesterol, and total triglycerides were analysed in plasma, and the lycopene content and the expression and activity of the enzyme HMGCR were determined in liver samples. A computational molecular modelling was carried out to determine the interactions between HMGCR and lycopene, chlorogenic acid and naringenin. Total, LDL and HDL cholesterol were significantly lower in the intervention group after the intake of tomato juice. In addition, a significant reduction in HMGCR activity was observed, although this was not accompanied by changes in gene expression. The molecular modelling showed that components of tomato can bind to the active site of the enzyme and compete with the ligand HMGCoA. Lycopene, from tomato juice, accumulates in the liver and can inhibit the activity of the rate-limiting enzyme of cholesterol biosynthesis, HMGCR. Studies suggest that tomato and soy foods may contribute to a lower risk of certain cancers. We developed a novel soy germ tomato juice to be used in controlled cancer prevention trials. This study describes an initial test of compliance, phytochemical bioavailability, and effects on biomarkers of blood lipids. Healthy men and women (n = 18) consumed a soy germ-fortified juice daily (300 mL supplying 66 mg isoflavones and 22 mg lycopene) for 8 wk. A single-dose bioavailability study was completed on day 1 and isoflavones in plasma and urine, and lycopene in the plasma, were measured. All subjects completed the trial, with 97.7% ± 3.5% (mean ± SD) of the scheduled juice consumed. No adverse effects were documented. The postprandial study indicated that 3.1% ± 2.3% of lycopene was absorbed and that 49.3% ± 12.1% isoflavones ingested were recovered in 24-h urines. Lycopene plasma concentration changed from 0.60 ± 0.22 to 1.24 ± 0.30 μmol/L during 8 wk of consumption. Juice consumption significantly improved resistance of LDL+VLDL-C to Cu(2+)-mediated oxidation (P = 0.039), HDL-C (47.3 ± 15.8 to 51.7 ± 14.8 mg/dL, P < 0.001), and the ratio of total-C/HDL-C (4.25 ± 1.59 to 3.63 ± 1.16, P < 0.001) at 8 wk. A well-characterized soy-fortified tomato juice can be produced in large scale for multiinstitutional long-term cancer prevention trials and showed excellent compliance with no toxicity, while demonstrating absorption of biologically active phytochemicals. High dietary intakes of tomato products are often associated with a reduced risk of CVD, but the atheroprotective mechanisms have not been established. This study was conducted to investigate the effects of increased dietary intake of tomato products on plasma lipids and LDL oxidation. The diet intervention included a baseline period, a 3-week low tomato diet (no tomato products allowed) and a 3-week high tomato diet (400 ml tomato juice and 30 mg tomato ketchup daily). Twenty-one healthy study subjects participated in the study. Total cholesterol concentration was reduced by 5.9 (sd 10) % (P = 0.002) and LDL cholesterol concentration by 12.9 (sd 17.0) % (P = 0.0002) with the high tomato diet compared to the low tomato diet. The changes in total and LDL cholesterol concentrations correlated significantly with the changes in serum lycopene (r 0.56, P = 0.009; r 0.60, P = 0.004, total and LDL, respectively), beta-carotene (r 0.58, P = 0.005; r 0.70, P < 0.001) and gamma-carotene concentrations (r 0.64, P = 0.002; r 0.64, P = 0.002). The level of circulating LDL to resist formation of oxidized phospholipids increased 13 % (P = 0.02) in response to the high tomato diet. In conclusion, a high dietary intake of tomato products had atheroprotective effects, it significantly reduced LDL cholesterol levels, and increased LDL resistance to oxidation in healthy normocholesterolaemic adults. These atheroprotective features associated with changes in serum lycopene, beta-carotene and gamma-carotene levels. Few epidemiologic studies have examined the potential cardiovascular mechanisms of tomato-based food products, the primary dietary source of lycopene. We examined the cross-sectional association between tomato-based food product intake and coronary biomarkers in the Women's Health Study. Tomato-based food products (tomatoes, tomato juice, tomato sauce, pizza) were summed from a semiquantitative FFQ and multiple risk factors ascertained. Plasma from baseline blood samples were assayed for lipids, lipoproteins, hemoglobin A1c, C-reactive protein, fibrinogen, soluble intracellular adhesion molecule-1, and creatinine. A total of 27,261 women aged ≥45 y who were free of cardiovascular disease and cancer provided relevant data for this study. Tomato-based food product intake was modest, with 84% of women consuming <1 serving/d, but those with greater intake had healthier lifestyle and dietary habits. Women consuming ≥10 compared with <1.5 servings/wk of tomato-based food products had significant but clinically modest improvements in total cholesterol (TC) (5.38 vs. 5.51 mmol/L; P = 0.029), the TC:HDL cholesterol ratio (4.08 vs. 4.22; P = 0.046), and hemoglobin A1c (5.02 vs. 5.13%; P < 0.001) in multivariable models. Considering clinical cutpoints, women consuming ≥10 compared with <1.5 servings/wk were 31% (95% CI = 6%, 50%), 40% (95% CI = 13%, 59%), and 66% (95% CI = 20%, 86%) less likely to have elevated TC (≥6.21 mmol/L), LDL cholesterol (≥4.14 mmol/L), and hemoglobin A1c (≥6%), respectively. Other coronary biomarkers were unassociated with tomato-based food products. In conclusion, women consuming ≥10 compared with <1.5 servings/wk of tomato-based food products had clinically modest but significant improvements in TC, the TC:HDL cholesterol ratio, and hemoglobin A1c but not other coronary biomarkers. |
312 | Are there transposon-free regions in mammalian genomes? | Yes. Despite the presence of over 3 million transposons separated on average by approximately 500 bp, the human and mouse genomes each contain almost 1000 transposon-free regions (TFRs) over 10 kb in length. The majority of human TFRs correlate with orthologous TFRs in the mouse, despite the fact that most transposons are lineage specific. Many human TFRs also overlap with orthologous TFRs in the marsupial opossum, indicating that these regions have remained refractory to transposon insertion for long evolutionary periods. Over 90% of the bases covered by TFRs are noncoding, much of which is not highly conserved. Most TFRs are not associated with unusual nucleotide composition, but are significantly associated with genes encoding developmental regulators, suggesting that they represent extended regions of regulatory information that are largely unable to tolerate insertions, a conclusion difficult to reconcile with current conceptions of gene regulation. | [21515576, 16365385, 18093339] | 419 | The Drosophila Gene Disruption Project (GDP) has created a public collection of mutant strains containing single transposon insertions associated with different genes. These strains often disrupt gene function directly, allow production of new alleles, and have many other applications for analyzing gene function. Here we describe the addition of ∼7600 new strains, which were selected from >140,000 additional P or piggyBac element integrations and 12,500 newly generated insertions of the Minos transposon. These additions nearly double the size of the collection and increase the number of tagged genes to at least 9440, approximately two-thirds of all annotated protein-coding genes. We also compare the site specificity of the three major transposons used in the project. All three elements insert only rarely within many Polycomb-regulated regions, a property that may contribute to the origin of "transposon-free regions" (TFRs) in metazoan genomes. Within other genomic regions, Minos transposes essentially at random, whereas P or piggyBac elements display distinctive hotspots and coldspots. P elements, as previously shown, have a strong preference for promoters. In contrast, piggyBac site selectivity suggests that it has evolved to reduce deleterious and increase adaptive changes in host gene expression. The propensity of Minos to integrate broadly makes possible a hybrid finishing strategy for the project that will bring >95% of Drosophila genes under experimental control within their native genomic contexts. BACKGROUND: We recently reported the existence of large numbers of regions up to 80 kb long that lack transposon insertions in the human, mouse and opossum genomes. These regions are significantly associated with loci involved in developmental and transcriptional regulation. RESULTS: Here we report that transposon-free regions (TFRs) are prominent genomic features of amphibian and fish lineages, and that many have been maintained throughout vertebrate evolution, although most transposon-derived sequences have entered these lineages after their divergence. The zebrafish genome contains 470 TFRs over 10 kb and a further 3,951 TFRs over 5 kb, which is comparable to the number identified in mammals. Two thirds of zebrafish TFRs over 10 kb are orthologous to TFRs in at least one mammal, and many have orthologous TFRs in all three mammalian genomes as well as in the genome of Xenopus tropicalis. This indicates that the mechanism responsible for the maintenance of TFRs has been active at these loci for over 450 million years. However, the majority of TFR bases cannot be aligned between distantly related species, demonstrating that TFRs are not the by-product of strong primary sequence conservation. Syntenically conserved TFRs are also more enriched for regulatory genes compared to lineage-specific TFRs. CONCLUSION: We suggest that TFRs contain extended regulatory sequences that contribute to the precise expression of genes central to early vertebrate development, and can be used as predictors of important regulatory regions. |
313 | Are messenger RNA molecules epigenetically methylated? | Yes, methyltranscriptome is an exciting new area that studies the mechanisms and functions of methylation in transcripts. | [24480744, 24768686, 25430002, 26458103, 25469751, 26121403, 25378335] | 420 | Recent discoveries of reversible N(6)-methyladenosine (m(6)A) methylation on messenger RNA (mRNA) and mapping of m(6)A methylomes in mammals and yeast have revealed potential regulatory functions of this RNA modification. In plants, defects in m(6)A methyltransferase cause an embryo-lethal phenotype, suggesting a critical role of m(6)A in plant development. Here, we profile m(6)A transcriptome-wide in two accessions of Arabidopsis thaliana and reveal that m(6)A is a highly conserved modification of mRNA in plants. Distinct from mammals, m(6)A in A. thaliana is enriched not only around the stop codon and within 3'-untranslated regions, but also around the start codon. Gene ontology analysis indicates that the unique distribution pattern of m(6)A in A. thaliana is associated with plant-specific pathways involving the chloroplast. We also discover a positive correlation between m(6)A deposition and mRNA abundance, suggesting a regulatory role of m(6)A in plant gene expression. miRNAs and DNA methylation are both critical regulators of gene expression. Aberration in miRNA expression or DNA methylation is a causal factor for numerous pathological conditions. DNA methylation can inhibit the transcription of miRNAs, just like coding genes, by methylating the CpG islands in the promoter regions of miRNAs. Conversely, certain miRNAs can directly target DNA methyltransferases and bring about their inhibition, thereby affecting the whole genome methylation pattern. Recently, methylation patterns have also been revealed in mRNA. Surprisingly, the two most commonly studied methylation states in mRNA (m6A and m5C) are found to be enriched in 3'-UTRs (untranslated regions), the target site for the majority of miRNAs. Whereas m5C is reported to stabilise mRNA, m6A has a destabilising effect on mRNA. However, the effect of mRNA methylation on its interaction with miRNAs is largely unexplored. The review highlights the complex interplay between microRNA and methylation at DNA and mRNA level. N(6)-methyladenosine (m6A) is the most abundant modified base in eukaryotic mRNA and has been linked to diverse effects on mRNA fate. Current mapping approaches localize m6A residues to transcript regions 100-200 nt long but cannot identify precise m6A positions on a transcriptome-wide level. Here we developed m6A individual-nucleotide-resolution cross-linking and immunoprecipitation (miCLIP) and used it to demonstrate that antibodies to m6A can induce specific mutational signatures at m6A residues after ultraviolet light-induced antibody-RNA cross-linking and reverse transcription. We found that these antibodies similarly induced mutational signatures at N(6),2'-O-dimethyladenosine (m6Am), a modification found at the first nucleotide of certain mRNAs. Using these signatures, we mapped m6A and m6Am at single-nucleotide resolution in human and mouse mRNA and identified small nucleolar RNAs (snoRNAs) as a new class of m6A-containing non-coding RNAs (ncRNAs). Methyltranscriptome is an exciting new area that studies the mechanisms and functions of methylation in transcripts. The MethylTranscriptome DataBase (MeT-DB, http://compgenomics.utsa.edu/methylation/) is the first comprehensive resource for N6-methyladenosine (m(6)A) in mammalian transcriptome. It includes a database that records publicaly available data sets from methylated RNA immunoprecipitation sequencing (MeRIP-Seq), a recently developed technology for interrogating m(6)A methyltranscriptome. MeT-DB includes ∼ 300 k m(6)A methylation sites in 74 MeRIP-Seq samples from 22 different experimental conditions predicted by exomePeak and MACS2 algorithms. To explore this rich information, MeT-DB also provides a genome browser to query and visualize context-specific m(6)A methylation under different conditions. MeT-DB also includes the binding site data of microRNA, splicing factor and RNA binding proteins in the browser window for comparison with m(6)A sites and for exploring the potential functions of m(6)A. Analysis of differential m(6)A methylation and the related differential gene expression under two conditions is also available in the browser. A global perspective of the genome-wide distribution of m(6)A methylation in all the data is provided in circular ideograms, which also act as a navigation portal. The query results and the entire data set can be exported to assist publication and additional analysis. |
314 | Which genes are more frequently affected by somatic mutations in Chronic Lymphocytic Leukemia | TP53, ATM, NOTCH1, XPO1, MYD88, KLHL6, SF3B1, ZMYM3, MAPK1, FBXW7 and DDX3X | [19367498, 22158541, 21642962, 22150006, 10803511, 22675518] | 421 | Here we perform whole-exome sequencing of samples from 105 individuals with chronic lymphocytic leukemia (CLL), the most frequent leukemia in adults in Western countries. We found 1,246 somatic mutations potentially affecting gene function and identified 78 genes with predicted functional alterations in more than one tumor sample. Among these genes, SF3B1, encoding a subunit of the spliceosomal U2 small nuclear ribonucleoprotein (snRNP), is somatically mutated in 9.7% of affected individuals. Further analysis in 279 individuals with CLL showed that SF3B1 mutations were associated with faster disease progression and poor overall survival. This work provides the first comprehensive catalog of somatic mutations in CLL with relevant clinical correlates and defines a large set of new genes that may drive the development of this common form of leukemia. The results reinforce the idea that targeting several well-known genetic pathways, including mRNA splicing, could be useful in the treatment of CLL and other malignancies. Chronic lymphocytic leukaemia (CLL), the most frequent leukaemia in adults in Western countries, is a heterogeneous disease with variable clinical presentation and evolution. Two major molecular subtypes can be distinguished, characterized respectively by a high or low number of somatic hypermutations in the variable region of immunoglobulin genes. The molecular changes leading to the pathogenesis of the disease are still poorly understood. Here we performed whole-genome sequencing of four cases of CLL and identified 46 somatic mutations that potentially affect gene function. Further analysis of these mutations in 363 patients with CLL identified four genes that are recurrently mutated: notch 1 (NOTCH1), exportin 1 (XPO1), myeloid differentiation primary response gene 88 (MYD88) and kelch-like 6 (KLHL6). Mutations in MYD88 and KLHL6 are predominant in cases of CLL with mutated immunoglobulin genes, whereas NOTCH1 and XPO1 mutations are mainly detected in patients with unmutated immunoglobulins. The patterns of somatic mutation, supported by functional and clinical analyses, strongly indicate that the recurrent NOTCH1, MYD88 and XPO1 mutations are oncogenic changes that contribute to the clinical evolution of the disease. To our knowledge, this is the first comprehensive analysis of CLL combining whole-genome sequencing with clinical characteristics and clinical outcomes. It highlights the usefulness of this approach for the identification of clinically relevant mutations in cancer. Although B cell chronic lymphocytic leukemia (B-CLL) has been traditionally viewed as a tumor of virgin B cells, this notion has been recently questioned by data suggesting that a fraction of B-CLL derives from antigen experienced B cells. In order to further clarify the histogenetic derivation of this lymphoproliferation, we have analyzed the DNA sequences of the 5' non-coding region of BCL-6 proto-oncogene in 28 cases of B-CLL. Mutations of BCL-6 proto-oncogene, a zinc finger transcription factor implicated in lymphoma development, represent a histogenetic marker of B cell transit through the germinal center (GC) and occur frequently in B cell malignancies derived from GC or post-GC B cells. For comparison, the same tumor panel was analyzed for somatic mutations of the rearranged immunoglobulin variable (IgV) genes, which are known to be acquired at the time of B cell transit through the GC. Sequence analyses of BCL-6 and IgV genes allowed the definition of three groups of B-CLL. Group I B-CLL displayed mutations of both BCL-6 and IgV genes (10/28; 36%). Group II B-CLL displayed mutated IgV genes, but a germline BCL-6 gene (5/28; 18%). Finally, group III B-CLL included the remaining cases (13/28; 46%) that were characterized by the absence of somatic mutations of both BCL-6 and IgV genes. Overall, the distribution of BCL-6 and IgV mutations in B-CLL reinforce the notion that this leukemia is histogenetically heterogeneous and that a substantial subgroup of these lymphoproliferations derives from post-germinal center B cells. Chronic lymphocytic leukemia (CLL) is a heterogeneous disease without a well-defined genetic alteration responsible for the onset of the disease. Several lines of evidence coincide in identifying stimulatory and growth signals delivered by B-cell receptor (BCR), and co-receptors together with NFkB pathway, as being the driving force in B-cell survival in CLL. However, the molecular mechanism responsible for this activation has not been identified. Based on the hypothesis that BCR activation may depend on somatic mutations of the BCR and related pathways we have performed a complete mutational screening of 301 selected genes associated with BCR signaling and related pathways using massive parallel sequencing technology in 10 CLL cases. Four mutated genes in coding regions (KRAS, SMARCA2, NFKBIE and PRKD3) have been confirmed by capillary sequencing. In conclusion, this study identifies new genes mutated in CLL, all of them in cases with progressive disease, and demonstrates that next-generation sequencing technologies applied to selected genes or pathways of interest are powerful tools for identifying novel mutational changes. |
315 | How effective is the dentritic cells treatment on cancer? | Another approach to cancer therapy takes advantage of the normal role of the dendritic cell as an immune educator. Dendritic cells grab antigens from viruses, bacteria, or other organisms and wave them at T cells to recruit their help in an initial T cell immune response. This works well against foreign cells that enter the body, but cancer cells often evade the self/non-self detection system. By modifying dendritic cells, researchers are able to trigger a special kind of autoimmune response that includes a T cell attack of the cancer cells. Because a cancer antigen alone is not enough to rally the immune troops, scientists first fuse a cytokine to a tumor antigen with the hope that this will send a strong antigenic signal. Next, they grow a patient's dendritic cells in the incubator and let them take up this fused cytokine-tumor antigen. This enables the dendritic cells to mature and eventually display the same tumor antigens as appear on the patient's cancer cells. When these special mature dendritic cells are given back to the patient, they wave their newly acquired tumor antigens at the patient's immune system, and those T cells that can respond mount an attack on the patient's cancer cells. | [20811715, 22042118, 23684423, 23369287, 19968878, 16221071, 17986000, 11022098, 21895989, 11570584, 22230748, 18684638] | 422 | PURPOSE: To morphometrically quantify CD1a+ dentritic cells and DC-SIGN+ dendritic cells in HIV-positive patients with anal squamous intraepithelial neoplasia and to evaluate the effects of HIV infection, antiretroviral therapy and HPV infection on epithelial and subepithelial dendritic cells. METHODS: A prospective study was performed to morphometrically analyze the relative volume of the dendritic cells and the relationship between anal intraepithelial neoplasia and cancer in HIV-positive patients from the Tropical Medicine Foundation of Amazonas, Brazil. All patients were submitted to biopsies of anorectal mucosa to perform a classic histopathological and immunohistochemical analysis, employing antibodies against CD1a and DC-SIGN for the morphometric quantification of dendritic cells. RESULTS: HIV-negative patients displayed a CD1a DC density significantly higher than that of HIV-positives patients (3.75 versus 2.54) (p=0.018), and in patients with severe anal intraepithelial neoplasia had correlated between DC CD1a density with levels of CD4 + cells (p: 0.04) as well as the viral load of HIV-1 (p: 0.035). A not significant rise in the median density of CD1a+ DC was observed in the HIV positive/ HAART positive subgroup compared to the HIV positive/ HAART negative subgroup. The CD1a+ DC were also significantly increased in HIV-negative patients with anorectal condyloma (2.33 to 3.53; p=0.05), with an opposite effect in HIV-positive patients. CONCLUSIONS: Our data support an enhancement of the synergistic action caused by HIV-HPV co-infection on the anal epithelium, weakening the DC for its major role in immune surveillance. Notoriously in patients with severe anal intraepithelial neoplasia, the density of CD1a+ epithelial dendritic cells was influenced by the viral load of HIV-1. Our study describes for the first time the density of subepithelial DC-SIGN+ dendritic cells in patients with anal severe anal intraepithelial neoplasia and points to the possibility that a specific therapy for HIV induces the recovery of the density of epithelial DC. The BAFF system plays a key role in the development of autoimmunity, especially in systemic lupus erythematosus (SLE). This often leads to the assumption that BAFF is mostly a B cell factor with a specific role in autoimmunity. Focus on BAFF and autoimmunity, driven by pharmaceutical successes with the recent approval of a novel targeted therapy Belimumab, has relegated other potential roles of BAFF to the background. Far from being SLE-specific, the BAFF system has a much broader relevance in infection, cancer and allergy. In this review, we provide the latest views on additional roles of the BAFF system in health and diseases, as well as an update on BAFF and autoimmunity, with particular focus on current clinical trials. BACKGROUND: In the direct pathway, T cells recognize intact donor major histocompatability complexes and allogeneic peptide on the surface of donor antigen presenting cells (APCs). Indirect allorecognition results from the recognition of processed alloantigen by self MHC complexes on self APCs. In this study, we wished to evaluate the relative contribution of different intragraft cells to the alloactivation of nave and memory T cells though the direct and the indirect pathway of allorecognition. METHODS: The processing of membrane fragments from IFN-treated single donor endothelial cells (EC), fibroblasts or renal epithelial cells (RPTEC) was evaluated by DiOC labeling of each cell type and flow cytometry following interaction with PBMC. Direct pathway activation of nave CD45RA+ or memory CD45RO+ CD4+ T cells was evaluated following coculture with IFN-treated and MHC class II-expressing EC, fibroblasts or RPTEC. Indirect pathway activation was assessed using CD45RA+ or CD45RO+ CD4+ T cells cocultured with autologous irradiated APCs in the absence or presence of sonicates derived from IFN-treated allogeneic EC, fibroblasts or RPTEC. Activation of T cells was assessed by [3H]thymidine incorporation and by ELISpot assays. RESULTS: We find that CD14+ APCs readily acquire membrane fragments from fibroblasts and RPTEC, but fail to acquire membrane fragments from intact EC. However, APCs process membranes from EC undergoing apoptosis.There was a notable direct pathway alloproliferative response of CD45RO+ CD4+ T cells to IFN-treated EC, but not to fibroblasts or RPTEC. Also, there was a minimal direct pathway response of CD45RA+ CD4+ T cells to all cell types. In contrast, we found that both CD45RA+ and CD45RO+ CD4+ T cells proliferated following coculture with autologous APCs in the presence of sonicates derived from IFN-treated EC, fibroblasts or RPTEC. By ELISpot, we found that these T cells stimulated via the indirect pathway also produced the cytokines IFN, IL-2, IL-4 and IL-5. CONCLUSIONS: Recipient APCs may readily process membrane fragments from allogeneic intragraft cells, but not from EC unless they are undergoing apoptosis. This processing is sufficient for indirect pathway alloactivation of both CD45RA+ and CD45RO+ CD4+ T cells. Only graft vascular EC mediate direct pathway reactivation of CD4+ T cells. BACKGROUND: CD1d-restricted iNKT cells are protective against murine melanoma B16F10-Nex2 growing subcutaneously in syngeneic C57Bl/6 mice as inferred from the fast tumor development in CD1d-KO in comparison with wild type animals. CD1d glycoproteins are related to the class I MHC molecules, and are involved in the presentation, particularly by dentritic cells (DC), of lipid antigens to iNKT cells. In the present work we attempted to identify the endogenous lipid mediator expressed in melanoma cells inducing such immunesurveillance response and study the possibility of protecting animals challenged with tumor cells with lipid-primed DC. RESULTS: Crude cytosolic and membrane fractions from in vivo growing melanoma contained iNKT-stimulating substances. Lipids were then extracted from these cells and one of the fractions (i.e. F3A) was shown to prime bone marrow-derived dendritic cells (BMDC) to stimulate iNKT murine hybridoma (DN32D3) cells to produce IL-2. The active fraction was analyzed by electrospray ionization-mass spectrometry (ESI-LIT-MS) and both iGb3 and iGb4 were identified along with GM3. When iGb3 was incubated with BMDC and tested with DN32D3 cells, IL-2 was equally produced indicating iNKT cell activation. GM3 consistently inhibited this response. To assess the antitumor response-induced by iGb3, a cytotoxicity assay in vitro was used with [3H]-thymidine labeled B16F10-Nex2 cells. At target/effector (iGb3-activated iNKT) cell ratio of 100(-1)-100(-4) tumor cell lysis was shown. The antitumor activity in vivo was tested in mice challenged i.v. with B16F10-Nex2 cells and treated with iGb3- or alpha-galactosylceramide-primed DCs. A 4-fold lower tumor load in the lungs was observed with either treatment. CONCLUSION: Our results show the expression of globo and isoglobohexosylceramides in murine melanoma B16F10-Nex2. The expression of iGb3 and its precursor, iGb4, on tumor cells may prime an effective iNKT cell-dependent antitumor response, modulated negatively by GM3 which is also produced in these cells. iGb3-primed BMDC exerted a significant iNKT cell-mediated anti-tumor activity in mice challenged with melanoma cells. Survivin, a member of the IAP family is an attractive target for cancer treatment due to it's over expression in most cancers and low or no expression in most differentiated adult tissues. Survivin expression is a poor prognostic marker in a number of cancers. Clinical trials are currently underway evaluating anti-sense oligonucleotides against Survivin, immunotherapy using Survivin primed dentritic cells and peptide mimics that block interaction of Survivin with Hsp90 resulting in loss of Survivin protein stability. Additional approaches using ribozymes against Survivin mRNA, or dominant-negative cDNA to block Survivin function are in pre-clinical stages. Like many genes, Survivin is alternately spliced and a number of new splice variants have recently been identified. Expression of some of these splice variants correlates with loss of steroid receptors as well as the tumor suppressor p53, in some cancers, suggesting that like wild-type Survivin, at least some of these splice variants may also have prognostic relevance. This review will focus on the current understanding of the function of Survivin splice variants and their expression and sub-cellular localization in normal and neoplastic tissues as well as critically evaluating the potential toxicity of the Survivin directed therapies and their predicted effect on the alternatively spliced Survivin isoforms. Dendritic cells are critical initiators of immune responses. They not only activate pathogen-specific T and B lymphocytes, they also stimulate cells of the innate immune system. Furthermore, dentritic cells are involved in immunological tolerance induction through the elimination of autoreactive T lymphocytes. Over the last ten years, understanding of the development, biology and physiopathology of dentritic cells has progressed considerably which has lead to the use of dentritic cells in immunotherapy protocols to treat tumors, infections and auto-immune diseases. The recently updated World Health Organization (WHO) classification of tumors of hematopoietic and lymphoid tissues, published in 2008, has made great advances in revising the disorders previously included in the pool of natural killer (NK) cell tumors. Although NK cell neoplasms represent a relatively rare group of diseases, accounting for <5% of all lymphoid neoplasms, they include very distinctive conditions both clinically and pathologically. This family of diseases includes the most indolent clinical forms, such as the provisional new entry of chronic lymphoproliferative disorder of NK cells (CLPD-NK) in the WHO classification, as well as one of the most fatal diseases recognized in medical oncology, aggressive NK cell leukemia (ANKL), which is characterized by a prognosis of weeks, or even days. In addition, some disorders previously identified as blastic NK cell lymphoma within the NK cell system have been more properly defined and included in the blastic plasmacytoid dentritic cell neoplasms, although rare cases of bona fide immature NK lymphoid tumors (now classified as NK cell lymphoblastic leukemia/lymphoma) have been reported in the literature. This paper focuses on recent concepts and progress in morphology, pathogenesis, clinicopathological features, treatment approaches, and outcomes of NK cell malignancies. Due to their central role in controlling immunity, dendritic cells are logical targets for priming naive cytotoxic T lymphocytes against tumour cells. In a strictly autologous system, we fused dendritic cells with melanoma cells, both of which were derived from patients with metastatic malignant melanoma. Hybridomas were positive for major histocompatibility complex (MHC) class II, CD40, CD54, CD83, CD86, and the pro-inflammatory cytokine interleukin-12. Autologous T lymphocytes were co-incubated with hybridomas. After 6 days, in-vitro-primed T lymphocytes revealed a strong proliferation activity and released Th-1-associated, but not Th-2-associated, cytokines. Furthermore they showed effective anti-melanoma activity, resulting in death of 70 +/- 9% of autologous melanoma cells. After depletion of CD4+ cells from the mixed population of primed T lymphocytes, the remaining CD8+ cells were able to kill 63+/-8% of autologous melanoma cells. Following depletion of CD8+ cells, however, the cytotoxic capacity of the remaining T lymphocytes caused death in only 32+/-6% of autologous melanoma cells. Blocking of MHC class I, but not class II, molecules on hybridomas impaired T cell proliferation, secretion of Th-1-associated cytokines, as well as the cytotoxic activity of primed T cells. These findings strongly suggest that hybridomas deliver melanoma-associated antigens via MHC class I molecules to T lymphocytes, resulting in the generation of CD8+ cytotoxic T lymphocytes with effective anti-melanoma activity in vitro. The data may serve as a basis for the use of hybridomas in the immunotherapy of malignant melanoma in vivo. It has been shown that silencing of suppressor of cytokine signalling 1 (Socs1) or stably expressing transgenic protein Ags in antigen-presenting dentritic cells (DCs) strongly enhances antigen-specific anti-tumour immunity. However, whether the strong and long-lasting T cell responses induced by the modified DCs could modulate the immunosuppressive tumour microenvironment has not been clarified. In this study, we explored the anti-tumour immunity of DCs modified by Socs1-shRNA lentiviral transduction combined with sustained expression of TRP2 in different tumour models. We showed that transfer Socs1-silenced or tumour antigen TRP2 persistent expressed DCs, or DCs modified by combination of Socs1-silencing and sustaining TRP2 expression prior to inoculation of tumour cells delayed B16 tumour cell growth, prolonged mouse survival and increased the ratio of CD8+ T/Treg as well as the CTL activity in tumours. However, there was no significant effect on tumour growth and mouse survival rate upon tumour established. Further, we showed that tumour cell secreted IL-10 counteracted the immunity of modified DCs in established tumour model, injection of Socs1-shRNA and TRP2 antigen modified significantly inhibited growth of the established B16-IL-10(-/-) tumours. These data indicated that the high level of IL-10 within tumour microenvironment is one of factors that compromise DC vaccine functions. Angioimmunoblastic T-cell lymphoma (AITL) is a rare and aggressive neoplasm clinically characterized by sudden onset of constitutional symptoms, lymphadenopathy, hepatosplenomegaly, frequent autoimmune phenomena, particularly hemolytic anemia and thrombocytopenia, and polyclonal hypergammaglobulinemia. The lymph node histological picture is also distinctive, constituted by a polymorphic infiltrate, a marked proliferation of high endothelial venules, and a dense meshwork of dentritic cells. The neoplastic CD4+ T-cells represent a minority of the lymph node cell population; its detection is facilitated by the aberrant expression of CD10. Almost all cases arbor an EBV infected B-cell population. Patients with AITL have a poor prognosis with conventional treatment, with a median overall survival of less than 3 years. Patients achieving a good clinical response seem beneficiate from a consolidation with high-dose therapy and autologous stem cell transplantation. Constitutional symptoms and autoimmune phenomena, and some times also the neoplastic masses may respond to immunosuppressive or immunomodulatory agents such as thalidomide. |
316 | What is the mode of inheritance of nemaline myopathy? | Nemaline myopathy has a autosomal dominant or recessive mode of inheritance. | [2213842, 17846275, 15336686] | 423 | OBJECTIVE: To describe the clinical, morphologic, and genetic findings in a family in which one woman had nemaline myopathy, whereas her daughter showed features of cap disease. PATIENTS: A 66-year-old woman and her 35-year-old daughter had congenital, slowly progressive muscle weakness. They had weakness in both proximal and distal muscles and facial diplegia with bilateral ptosis, a long narrow face, a high arched palate, and micrognathia. RESULTS: Muscle biopsy specimens in the mother at age 57 years had shown nemaline myopathy, whereas a biopsy specimen at age 32 years had demonstrated no rods. Muscle biopsy specimens in the daughter at age 26 years had shown features of cap disease and no apparent nemaline rods. A missense mutation, Glu41Lys, in the beta-tropomyosin gene TPM2 was identified in both patients but was absent in their healthy relatives. CONCLUSIONS: The results indicate that mutations in TPM2 may cause nemaline myopathy as well as cap disease with a dominant mode of inheritance. These disorders may thus be phenotypic variants of the same genetic defect. We present comparisons of the clinical pictures in a series of 60 patients with nemaline myopathy in whom mutations had been identified in the genes for nebulin or skeletal muscle alpha-actin. In the patients with nebulin mutations, the typical form of nemaline myopathy predominated, while severe, mild or intermediate forms were less frequent. Autosomal recessive inheritance had been verified or appeared likely in all nebulin cases. In the patients with actin mutations, the severe form of nemaline myopathy was the most common, but some had the mild or typical form, and a few showed other associated features such as intranuclear rods or actin accumulation. Most cases were sporadic, but in addition there were instances of both autosomal dominant and autosomal recessive inheritance, while two families showed mosaicism for dominant mutations. Although no specific phenotype was found to be associated with mutations in either gene, clinical and histological features together with pedigree data may be used in guiding mutation detection. Finding the causative mutation(s) determines the mode of inheritance and permits prenatal diagnosis if requested, but will not as such permit prognostication. |
317 | Which syndrome is NHE6 associated with? | Mutations in the solute carrier family 9, subfamily A member 6 (SLC9A6) gene, encoding the endosomal Na+/H+ exchanger 6 (NHE6) are associated with Christianson syndrome, a syndromic form of X-linked intellectual disability characterized by microcephaly, severe global developmental delay, autistic behavior, early onset seizures and ataxia. | [25044251, 24035762, 24630051, 20949524] | 424 | OBJECTIVE: Recently, Christianson syndrome (CS) has been determined to be caused by mutations in the X-linked Na(+) /H(+) exchanger 6 (NHE6). We aimed to determine the diagnostic criteria and mutational spectrum for CS. METHODS: Twelve independent pedigrees (14 boys, age = 4-19 years) with mutations in NHE6 were administered standardized research assessments, and mutations were characterized. RESULTS: The mutational spectrum was composed of 9 single nucleotide variants, 2 indels, and 1 copy number variation deletion. All mutations were protein-truncating or splicing mutations. We identified 2 recurrent mutations (c.1498 c>t, p.R500X; and c.1710 g>a, p.W570X). Otherwise, all mutations were unique. In our study, 7 of 12 mutations (58%) were de novo, in contrast to prior literature wherein mutations were largely inherited. We also report prominent neurological, medical, and behavioral symptoms. All CS participants were nonverbal and had intellectual disability, epilepsy, and ataxia. Many had prior diagnoses of autism and/or Angelman syndrome. Other neurologic symptoms included eye movement abnormalities (79%), postnatal microcephaly (92%), and magnetic resonance imaging evidence of cerebellar atrophy (33%). Regression was noted in 50%, with recurrent presentations involving loss of words and/or the ability to walk. Medical symptoms, particularly gastrointestinal symptoms, were common. Height and body mass index measures were below normal ranges in most participants. Behavioral symptoms included hyperkinetic behavior (100%), and a majority exhibited high pain threshold. INTERPRETATION: This is the largest cohort of independent CS pedigrees reported. We propose diagnostic criteria for CS. CS represents a novel neurogenetic disorder with general relevance to autism, intellectual disability, Angelman syndrome, epilepsy, and regression. Neuronal arborization is regulated by cell-autonomous and nonautonomous mechanisms including endosomal signaling via BDNF/TrkB. The endosomal Na⁺/H⁺ exchanger 6 (NHE6) is mutated in a new autism-related disorder. NHE6 functions to permit proton leak from endosomes, yet the mechanisms causing disease are unknown. We demonstrate that loss of NHE6 results in overacidification of the endosomal compartment and attenuated TrkB signaling. Mouse brains with disrupted NHE6 display reduced axonal and dendritic branching, synapse number, and circuit strength. Site-directed mutagenesis shows that the proton leak function of NHE6 is required for neuronal arborization. We find that TrkB receptor colocalizes to NHE6-associated endosomes. TrkB protein and phosphorylation are reduced in NHE6 mutant neurons in response to BDNF signaling. Finally, exogenous BDNF rescues defects in neuronal arborization. We propose that NHE6 mutation leads to circuit defects that are in part due to impoverished neuronal arborization that may be treatable by enhanced TrkB signaling. |
318 | What is known about the reimbursement of Viagra | Coverage of Viagra/Sildenafil for erectile dysfunction by health insurance plans is a contentious issue in developed countries. There are data of the limitations (6 per month) and co-payments (26.6%) by patients in the US.
The costs for Viagra/Sildenafil for PAH (pulmonary artery hypertension) appear to be covered by health insurances in the US. | [12119585, 12442853, 20608882, 23231890, 14769012, 19715380, 10718038, 21073206, 14769010, 16194131, 10345973, 22554140, 10858175] | 425 | The article describes the controversy about the question whether statutory social health insurances are obliged to reimburse the costs for the treatment of erectile dysfunction. Next to the question whether the 'Bundesausschuss der Arzte und Krankenkassen' was entitled to decide it was highly controversial whether erectile dysfunction is a disease according to the laws of social insurance. This enforces more general considerations regarding the possibility to define disease and the relevancy of a concept of disease for the justification and limitation of socially financed services in medicine. OBJECTIVE: To explore treatment patterns and resource utilization and cost for subjects with pulmonary arterial hypertension (PAH). RESEARCH DESIGN: Retrospective claims database analysis of 706 patients with PAH enrolled in a large, geographically diverse US managed-care organization. RESULTS: In the final sample of PAH patients treated with bosentan (n=251) or sildenafil (n=455), average age was 57 years, 86% of patients were commercially insured, and 52% of patients were male. Gender distribution varied significantly across subgroups, with a lower proportion of males in the bosentan (30%) subgroup compared with the sildenafil group (64%) (p<0.001). Average baseline Charlson comorbidity score was 2.4. Average numbers of fills per month were 0.8 and 0.4 for bosentan and sildenafil patients, respectively (p<0.001). Over 80% of patients received only one PAH treatment in the first 90 days following the index date, with 28% of bosentan and 13% of sildenafil patients receiving combination therapy (p<0.001). Over one-third of bosentan patients and one-quarter of sildenafil patients experienced a dose increase in the follow-up period (p=0.009). Sixteen percent of sildenafil patients experienced a dose decrease in the follow-up period, while a smaller proportion of patients receiving bosentan (4%) experienced a dose decrease (p<0.001). On average, number of PAH-related per subject per month (PSPM) inpatient stays and emergency department visits and PSPM length of inpatient stays were statistically similar between the subgroups. PAH-related PSPM healthcare costs were high for both subgroups, with average monthly costs of $5,332 and $3,632 among bosentan and sildenafil patients, respectively (p=0.003). Differences in total costs were driven mainly by differences in pharmacy expenditures. CONCLUSIONS: Of the oral agents approved for treating PAH at the time of this study, sildenafil was most commonly prescribed as index therapy and was also associated with the lowest costs, largely due to significantly lower pharmacy costs. This study is characterized by limitations inherent to claims database analyses, such as the potential for coding errors and lack of information on whether a drug was taken as prescribed. Furthermore, PAH severity (WHO functional class) was not assessed. BACKGROUND: Little is known concerning the degree to which initiation of sildenafil for pulmonary arterial hypertension (PAH) impacts patterns of healthcare utilization and costs. METHODS: Using a large US health insurance claims database, we identified all patients with evidence of PAH (ICD-9-CM diagnosis codes 416.0, 416.8) who received sildenafil between 1/1/2005 and 9/30/2008. Date of the first-noted prescription for sildenafil was designated the "index date," and claims data were compiled for all study subjects for 6 months prior to their index date ("pretreatment") and 6 months thereafter ("follow-up"); patients with incomplete data during either of these periods were excluded. Healthcare utilization and costs were then compared between pretreatment and follow-up for all study subjects. RESULTS: A total of 567 PAH patients were identified who began therapy with sildenafil and met all other study entry criteria. Mean (SD) age was 52 (10) years; 73% were women. Healthcare utilization was largely unchanged between pretreatment and follow-up, the only exceptions being decreases in the mean number of emergency department visits (from 0.7 to 0.5 per patient; p<0.01) and the percentage of patients hospitalized (from 35% to 29%; p=0.01). The mean cost of all PAH-related medication was $7139 during pretreatment and $14,095 during follow-up (sildenafil cost during follow-up= $5236); exclusive of PAH-related medications, however, total healthcare costs decreased modestly (from $30,104 to $27,605) (p<0.01 for all comparisons). CONCLUSIONS: The cost of sildenafil therapy may be partially offset by reductions in other healthcare costs. BACKGROUND: Inclusion or not of a treatment strategy in the publicly financed health care is really a matter of prioritisation. In Sweden priority setting decisions are governed by law in which it is stated that decisions should be guided by firstly the principle of need and secondly the principle of cost-effectiveness. OBJECTIVE: The purpose of the paper is to discuss and illustrate the roles of need and cost-effectiveness in decisions on inclusion or not of treatment strategies in the publicly financed health care. METHODS: The theoretical backgrounds of need and cost-effectiveness are discussed in short, both with respect to their meaning and to their potential roles in decisions on priority setting. Four treatment strategies, Viagra, Rivastigmine, statins, and lung transplants, are analysed with respect to whether either cost-effectiveness or need, or both, seem to have played a role in the decisions of inclusion or not in the basic health care package. RESULTS: Both need and cost-effectiveness are important and should be important aspects when making decisions on priority setting. From the examples of the four treatment strategies it seems that decisions are almost exclusively made with reference to the principle of need. CONCLUSIONS: The most evident conclusion to be drawn from this study is that decisions on priority setting are almost solely based on the principle of need. This implies that the principle of cost-effectiveness is given very little space, which is a problem as this means an obvious risk of inefficient resource use. BACKGROUND AND OBJECTIVE: Clinicians must choose between an increasing number of medications for the treatment of pulmonary arterial hypertension (PAH) with different routes of administration, adverse effects, costs and efficacies. We constructed a decision analysis to help inform treatment choices in PAH. METHODS: We created a Markov-type model to evaluate 1-year treatment with bosentan, treprostinil, epoprostenol, inhaled iloprost, sildenafil, sitaxentan and ambrisentan. Transition probabilities were based on observed transitions between WHO functional classes, adjusted by relative risk of improvement in a 6-minute walk test. Utilities were based on reported values for each functional class, adjusted for burden of treatment administration. Costs were estimated from Medicare and Medicaid reimbursement data. Sensitivity analyses evaluated changes in efficacy, utilities and costs. RESULTS: Treatment with sildenafil was less costly and resulted in a greater gain in quality-adjusted life-years (QALYs) compared with other treatments. Treatment with ambrisentan and bosentan resulted in the same gain in QALYs as sildenafil, but at a higher cost. Sensitivity analyses had minimal impact on these results. CONCLUSIONS: Based on this model, sildenafil is a cost-effective treatment for PAH with a low price and a net increase in QALYs. The results from this analysis are a tool to help guide clinicians in deciding which PAH medications to use; however, the final decisions should be individualized because the effectiveness of therapy, resulting utilities and acceptable costs will differ with each patient. This paper discusses the problematic and sometimes implicit nature of some central notions and criteria used in debates about inclusion (or exclusion) of health care services in the health care benefit package. An analysis of discussions about four health care services--lungtransplantation, statins, (sildenafil (viagra) and rivastigmine--illustrates a case-by-case approach and inconsistent use of criteria, which present a challenge to develop a decision-making procedure in which important criteria or central notions can be discussed explicitly. OBJECTIVE: Erectile dysfunction (ED) affects approximately 30 million men in the United States. The objectives of this study were to (1) assess the cost and utilization of sildenafil citrate (Viagra), an oral therapeutic agent for ED, in a large managed care organization (MCO) with a quantity limit of 6 units per 30-day supply and (2) describe the incidence of comorbid conditions and the severity of cardiovascular disease in adult male users of sildenafil. METHODS: Pharmacy claims for sildenafil were identified from an administrative database of claims with dates of service in calendar year 2001 for male members aged 18 years or older. Medical claims for MCO members who had sildenafil claims were used to identify comorbid diseases and categorize patients by degree of cardiovascular risk. High risk was defined as having at least 1 medical claim with a diagnosis of diabetes mellitus, ischemic heart disease, abdominal aortic aneurysm, or peripheral arterial disease, and medium risk was defined as not having any diagnosis in the high-risk category but at least 1 cardiovascular risk factor that included smoking, hypertension, hypercholesterolemia, family history of premature coronary heart disease, or being aged 45 years or older. RESULTS: There were 67,914 pharmacy claims for sildenafil during 2001 for 20,281 MCO members, an average of 3.3 pharmacy claims per patient. The prevalence of sildenafil use was 54.1 per 1,000 male MCO members aged 18 years or older. The total allowed charges for sildenafil pharmacy claims in 2001 were 3.56 million US dollars, of which patients paid 26.6% in average cost-share, and the net MCO cost per member per month (PMPM) was 0.18 US dollars. A total of 1,681 patients (8.3%) exceeded their quantity restrictions for sildenafil tablets in 2001, of which 1,362 (81.0%) paid cash and 319 (19.0%, or 1.6% of all sildenafil users) appealed and received approval from the MCO for additional sildenafil tablets beyond the restriction of 6 tablets per month. Medical claims were available for 15,644 sildenafil patients (77.1%), and 12,720 sildenafil users (81.3% of those with medical claims) were judged to be at high or medium cardiovascular risk. CONCLUSIONS: A quantity limit of 6 tablets of sildenafil per 30-day period was associated with a drug cost to users and the MCO of 0.25 US dollars PMPM. Sildenafil users paid an average cost-share of 26.6%, resulting in a net drug cost of 0.18 US dollars PMPM to the MCO. OBJECTIVES: To describe treatment patterns and healthcare burden among individuals with suspected pulmonary arterial hypertension (PAH), as identified through a practice guideline-based healthcare claims algorithm. METHODS: Adults with evidence of PAH from 1 January 2004 (commercial and Medicaid) or 1 July 2006 (Medicare Advantage) through 30 June 2008 were identified. Given the lack of an ICD-9 code for PAH, an algorithm was developed requiring: (1) ≥ 1 claim for PAH medication (index date); (2) ≥ 1 claim with a pulmonary hypertension diagnosis code in the 6-month pre-index period (baseline) or within 90 days post-index; (3) a right heart catheterization or pulmonary hypertension-related inpatient stay during baseline or within 90 days post-index; and (4) continuous health plan enrollment for 6 months pre-index and ≥ 6 months post-index. Patients with PAH-specific medications during baseline were excluded. Treatment patterns, healthcare utilization, and costs were assessed during the period ending with the earlier of health plan disenrollment or 31 December 2008. RESULTS: Among the 521 included patients, 69% were female. Most patients (94%) initiated treatment with monotherapy (most commonly sildenafil or bosentan), and 12.7% of all patients augmented their therapy by the end of the observation period. The medication possession ratio was 0.96 each for ambrisentan (SD=0.04), bosentan (SD=0.04), and sildenafil (SD=0.05). Overall, 72.6% of patients discontinued therapy with a mean of 149 (SD=170) days until discontinuation. A mean (SD) of 2.14 (1.82) all-cause office and 1.64 (1.98) outpatient visits occurred per patient per month. Mean PAH-related healthcare costs were $6617 per patient per month, comprising 71% of all-cause costs. The guideline-based algorithm may not have perfectly captured patients with PAH. CONCLUSIONS: Patients with suspected PAH were likely to initiate treatment with oral monotherapy, had high compliance rates, and received close ambulatory follow-up. PAH-related costs constituted the majority of all-cause healthcare costs. |
319 | Why is lock mass used in Orbitrap measurements? | The lock mass is a compound of known mass and is used to compensate for drifts in instrument calibration. | [21133379, 21953191, 16249172, 22941912, 16478717] | 426 | The positive role and application of highly accurate mass measurements in proteomics is well documented. The new generation of hybrid FTMS and Q-TOF instruments, including the LTQ-Orbitrap (OT), is remarkable in their ability to routinely produce single-digit to subppm statistical mass accuracy while maintaining high analytical sensitivity. The use of mass calibrants (lock masses) to reduce the systematic error of mass-to-charge measurements has also been reported and, in some cases, incorporated in the instrument control software by the instrument manufacturers. We evaluated the use of one such calibrant in the OT (e.g., polydimethylcyclosiloxane, PCM) to study its impact on the rate of phosphopeptide annotation and found it to lack robustness under normal laboratory conditions. Therefore, we devised a strategy to improve its performance by increasing the external abundance of calibrant molecules in laboratory air. This resulted in a more robust performance of the preprogrammed lock mass recalibration feature as evidenced by improvements in both statistical mass accuracy and peptide annotation rates. Mass accuracy is a key parameter in proteomic experiments, improving specificity, and success rates of peptide identification. Advances in instrumentation now make it possible to routinely obtain high resolution data in proteomic experiments. To compensate for drifts in instrument calibration, a compound of known mass is often employed. This 'lock mass' provides an internal mass standard in every spectrum. Here we take advantage of the complexity of typical peptide mixtures in proteomics to eliminate the requirement for a physical lock mass. We find that mass scale drift is primarily a function of the m/z and the elution time dimensions. Using a subset of high confidence peptide identifications from a first pass database search, which effectively substitute for the lock mass, we set up a global mathematical minimization problem. We perform a simultaneous fit in two dimensions using a function whose parameterization is automatically adjusted to the complexity of the analyzed peptide mixture. Mass deviation of the high confidence peptides from their calculated values is then minimized globally as a function of both m/z value and elution time. The resulting recalibration function performs equal or better than adding a lock mass from laboratory air to LTQ-Orbitrap spectra. This 'software lock mass' drastically improves mass accuracy compared with mass measurement without lock mass (up to 10-fold), with none of the experimental cost of a physical lock mass, and it integrated into the freely available MaxQuant analysis pipeline ( www.maxquant.org ). A recent trend in the use of high resolution accurate mass screening (HRAMS) for doping control testing in both human and animal sports has emerged due to significant improvement in high resolution mass spectrometry in terms of sensitivity, mass accuracy, mass resolution, and mass stability. A number of HRAMS methods have been reported for the detection of multi-drug residues in human or equine urine. As blood has become a common matrix for doping control analysis, especially in equine sports, a sensitive, fast and wide coverage screening method for detecting a large number of drugs in equine blood samples would be desirable. This paper presents the development of a liquid chromatography-high resolution mass spectrometry (LC-HRMS) screening method for equine plasma samples to cover over 320 prohibited substances in a single analytical run. Plasma samples were diluted and processed by solid-phase extraction. The extracts were then analyzed with LC-HRMS in full-scan positive electrospray ionization mode. A mass resolution of 60 000 was employed. Benzyldimethylphenylammonium was used as an internal lock mass. Drug targets were identified by retention time and accurate mass, with a mass tolerance window of ±3 ppm. Over 320 drug targets could be detected in a 13-min run. Validation data including sensitivity, specificity, extraction recovery and precision are presented. As the method employs full-scan mass spectrometry, an unlimited number of drug targets can theoretically be incorporated. Moreover, the HRAMS data acquired can be re-processed retrospectively to search for drugs which have not been targeted at the time of analysis. |
320 | Which virus is Cidofovir (Vistide) indicated for? | Cidofovir is commonly used in the treatment of cytomegalovirus (CMV) infection and disease. | [11154213, 11772283, 9814660, 19725597] | 427 | A retrospective study was performed to collect information regarding efficacy and toxicity of cidofovir (CDV) in allogeneic stem cell transplant patients. Data were available on 82 patients. The indications for therapy were cytomegalovirus (CMV) disease in 20 patients, primary preemptive therapy in 24 patients, and secondary preemptive therapy in 38 patients. Of the patients, 47 had received previous antiviral therapy with ganciclovir, foscarnet, or both drugs. The dosage of CDV was 1 to 5 mg/kg per week followed by maintenance every other week in some patients. The duration of therapy ranged from 1 to 134 days (median, 22 days). All patients received probenecid and prehydration. Ten of 20 (50%) patients who were treated for CMV disease (9 of 16 with pneumonia) responded to CDV therapy, as did 25 of 38 (66%) patients who had failed or relapsed after previous preemptive therapy and 15 of 24 (62%) patients in whom CDV was used as the primary preemptive therapy. Of the patients, 21 (25.6%) developed renal toxicity that remained after cessation of therapy in 12 patients. Fifteen patients developed other toxicities that were potentially due to CDV or the concomitantly given probenecid. No toxicity was seen in 45 (61.6%) patients. Cidofovir can be considered as second-line therapy in patients with CMV disease failing previous antiviral therapy. However, additional studies are needed before CDV can be recommended for preemptive therapy. Cytomegalovirus (CMV) infection is very common throughout the world, and has become more of a pediatric clinical concern given the high incidence of congenital CMV infections as well as the increasing numbers of immunocompromised patients. Because of this, the need for antiviral therapies in infants and neonates is growing. Currently, there are four antivirals available that are active against CMV: ganciclovir, valganciclovir, foscarnet, and cidofovir. At this time, none have approved indications for use in children. Although there are limited data regarding the dose, pharmacokinetics (PK), safety, and adverse events for some of these antivirals, ganciclovir, and its oral prodrug valganciclovir, have been the best studied in the infant and neonate populations. In general, pharmaceutical PK studies in young children are limited by the constraints of sampling difficulties and blood volume requirements; fewer sampling times and studies may be available for drug evaluation. Given this caveat, ganciclovir and valganciclovir PK in children thus far appears to follow a monocompartmental model, contrary to what has been described in adults. However, when normalized for weight, the volume of distribution, clearance, and half-life of ganciclovir are similar to those found in adults. Given the findings that ganciclovir (and thus valganciclovir) clearance is directly proportionate to renal function, care must be taken when administering the drug to patients with impaired renal function. Recent studies evaluating valganciclovir PK in infants (at a dose of 16 mg/kg every 12 hours) have shown similar areas under the plasma concentration-time curve (AUCs) to intravenous ganciclovir (at a dose of 6 mg/kg every 12 hours), and that these AUCs remain quite stable over a number of weeks. As seen in adults, oral ganciclovir has a low bioavailability (4.8% in a pediatric analysis) and is therefore a poor alternative for treating serious CMV infections. Neutropenia is the most frequent toxicity associated with ganciclovir and valganciclovir therapy, whereas significant (and possibly irreversible) renal toxicity can be seen with cidofovir. Foscarnet administration can also result in renal toxicity as well as significant electrolyte imbalances. Several of these drugs have potential toxicities that are of concern, including carcinogenesis, teratogenesis, and azospermia (ganciclovir, valganciclovir, and cidofovir) and deposition into bone or dentition (foscarnet) that may have significant implications when treating an infant. Given these potential ill effects, careful consideration of the indications for the clinical use of these antivirals is necessary before using them for CMV infection in neonates and infants. |
321 | Have gnotobiotic animal models been used for the study of bowel disease? | Yes, gnotobiotic animals (e.g. mice) have been used for the study of bowel disease (e.g. inflammatory bowel disease). | [24959425, 21426337, 2765093, 18841702, 17145736, 11984521, 20004202, 24500617, 16127016, 21278760, 12906096, 16954804] | 428 | Campylobacter jejuni infections have a high prevalence worldwide and represent a significant socioeconomic burden. C. jejuni can cross the intestinal epithelial barrier as visualized in biopsies derived from human patients and animal models, however, the underlying molecular mechanisms and associated immunopathology are still not well understood. We have recently shown that the secreted serine protease HtrA (high temperature requirement A) plays a key role in C. jejuni cellular invasion and transmigration across polarized epithelial cells in vitro. In the present in vivo study we investigated the role of HtrA during C. jejuni infection of mice. We used the gnotobiotic IL-10(-/-) mouse model to study campylobacteriosis following peroral infection with the C. jejuni wild-type (WT) strain NCTC11168 and the isogenic, non-polar NCTC11168ΔhtrA deletion mutant. Six days post infection (p.i.) with either strain mice harbored comparable intestinal C. jejuni loads, whereas ulcerative enterocolitis was less pronounced in mice infected with the ΔhtrA mutant strain. Moreover, ΔhtrA mutant infected mice displayed lower apoptotic cell numbers in the large intestinal mucosa, less colonic accumulation of neutrophils, macrophages and monocytes, lower large intestinal nitric oxide, IFN-γ, and IL-6 as well as lower TNF-α and IL-6 serum concentrations as compared to WT strain infected mice at day 6 p.i. Notably, immunopathological responses were not restricted to the intestinal tract given that liver and kidneys exhibited mild histopathological changes 6 days p.i. with either C. jejuni strain. We also found that hepatic and renal nitric oxide levels or renal TNF-α concentrations were lower in the ΔhtrA mutant as compared to WT strain infected mice. In conclusion, we show here that the C. jejuni HtrA protein plays a pivotal role in inducing host cell apoptosis and immunopathology during murine campylobacteriosis in the gut in vivo. To model inflammatory bowel disease, we assessed infection with Helicobacter hepaticus 3B1 (ATCC 51449) and a potential probiotic Lactobacillus reuteri (ATCC PTA-6475) in gnotobiotic B6.129P2-IL-10(tm1Cgn) (IL-10(-/-) ) mice. No typhlocolitis developed in germ-free controls (n=21) or in L. reuteri (n=8) or H. hepaticus (n=18) mono-associated mice for 20 weeks post-infection. As positive controls, three specific pathogen-free IL-10(-/-) mice dosed with H. hepaticus developed severe typhlocolitis within 11 weeks. Because L. reuteri PTA-6475 has anti-inflammatory properties in vitro, it was unexpected to observe significant typhlocolitis (P<0·0001) in mice that had been infected with L. reuteri followed in 1 week by H. hepaticus (n=16). The H. hepaticus colonization was not affected through 20 weeks post-infection but L. reuteri colonization was lower in co-infected compared with L. reuteri mono-associated mice at 8-11 weeks post-infection (P<0·05). Typhlocolitis was associated with an increased T helper type 1 serum IgG2c response to H. hepaticus in co-infected mice compared with H. hepaticus mono-associated mice (P<0·005) and similarly, mRNA expression in caecal-colonic tissue was elevated at least twofold for chemokine ligands and pro-inflammatory interleukin-1α (IL-1α), IL-1β, IL-12 receptor, tumour necrosis factor-α and inducible nitric oxide synthase. Anti-inflammatory transforming growth factor-β, lactotransferrin, peptidoglycan recognition proteins, Toll-like receptors 4, 6, 8 and particularly 9 gene expression, were also elevated only in co-infected mice (P<0·05). These data support that the development of typhlocolitis in H. hepaticus-infected IL-10(-/-) mice required co-colonization with other microbiota and in this study, required only L. reuteri. Although the effects other microbiota may have on H. hepaticus virulence properties remain speculative, further investigations using this gnotobiotic model are now possible. The pathogenesis of enteric changes was studied in gnotobiotic piglets which, after hysterectomy had been infected orally with Campylobacter jejuni on the first day of their life. The involvement of the entire large intestine became clinically manifest by scouring on days post infection (DPI) 4 to DPI 5, and pathomorphologically, by simultaneous inflammation and severe edema of the intestinal wall. Histology and SEM revealed inflammatory edema with abundant neutrophils, microulcerations, focal propagation and activation of goblet cells, and a presence of mucin-positive material within the intestinal lumen. TEM examination revealed disconnected interdigitating folds and wide dilated intercellular spaces between enterocytes. The endothelial cells of small blood vessels in the lamina propria showed hypertrophy with increase in the thickness of their basal lamina. Ultrastructural lesions of the large intestinal microcirculation also support the hypothesis that disturbances in the vascular system are responsible for edema in the cecum and colon. Gnotobiotic piglets may be used as a suitable animal model to study colitis induced by C. jejuni. BACKGROUND & AIMS: Recently, a number of animal models for different aspects of inflammatory bowel disease (IBD) have been developed. The aim of this study was to use one of these to determine whether particular, ostensibly innocuous, intestinal bacteria could provoke or exacerbate IBD. METHODS: Conventionally reared C.B17 SCID mice were compared with germ-free and gnotobiotic mice, monoassociated with 1 of 5 intestinal bacteria, after transfer of CD45RB(high) CD4(+) T cells from conventionally reared congenic BALB/c mice. Recipient mice were monitored over 7-12 weeks for clinical signs of IBD, and tissues were analyzed by histology/flow cytometry for abnormal inflammation and CD4(+) T cell outgrowth. RESULTS: Neither germ-free mice nor mice monoassociated with segmented filamentous bacteria, Ochrobactrum anthropi, a nonpathogenic mutant of Listeria monocytogenes, or Morganella morganii developed any signs of IBD. In contrast, mice monoassociated with Helicobacter muridarum displayed an accelerated development of IBD in 5-6 weeks compared with 8-12 weeks observed in conventionally reared mice. The outgrowth of CD4(+) T cells in spleen and large intestine of H. muridarum monoassociated mice, as well as in conventionally reared mice was significantly higher than that in the other monoassociated mice. CONCLUSIONS: Among the intestinal bacteria tested, H. muridarum can serve as a provocateur of IBD in this model. BACKGROUND & AIMS: Klotho (KL) is an anti-inflammatory protein that protects the endothelium from nitric oxide (NO)-induced dysfunction, reduces the expression of endothelial adhesion molecules, and potentially regulates T-cell functions. KL deficiency leads to premature senescence and impaired Ca2+/Pi homeostasis, which can lead to inflammatory bowel disease (IBD)-associated osteopenia/osteoporosis. We investigated the changes in renal expression of Kl as a consequence of colitis. METHODS: We studied 3 mouse models of IBD: colitis induced by trinitrobenzene sulfonic acid, colitis induced by microflora (in gnotobiotic interleukin-10(-/-)), and colitis induced by adoptive transfer of CD4(+)CD45RB(high) T cells. Effects of the tumor necrosis factor (TNF) and interferon (IFN)-gamma on Kl expression and the activity of its promoter were examined in renal epithelial cells (mpkDCT4 and mIMCD3). RESULTS: Renal expression of Kl messenger RNA (mRNA) and protein was reduced in all 3 models of IBD. Reduced level of KL correlated with the severity of colitis; the effect was reversed by neutralizing antibodies against TNF. In vitro, TNF inhibited Kl expression, an effect potentiated by IFN-gamma. The combination of TNF and IFN-gamma increased expression of inducible nitric oxide synthase (iNOS) and increased NO production. The effect of IFN-gamma was reproduced by exposure to an NO donor and reversed by the iNOS inhibitor. In cells incubated with TNF and/or IFN-gamma, Kl mRNA stability was unaffected, whereas Kl promoter activity was reduced, indicating that these cytokines regulate Kl at the transcriptional level. CONCLUSIONS: The down-regulation of KL that occurs during inflammation might account for the extraintestinal complications such as abnormalities in bone homeostasis that occur in patients with IBD. Initial events and effector mechanisms of most inflammatory and autoimmune diseases remain largely unknown. Dysfunction of the innate and adaptive immune systems associated with mucosae (the major interface between the organism and its environment, e.g., microbiota, food) can conceivably cause impairment of mucosal barrier function and development of localized or systemic inflammatory and autoimmune processes. Animal models help in elucidating the etiology and pathogenetic mechanisms of human diseases, such as the inflammatory bowel diseases, Crohn's disease and ulcerative colitis, severe chronic diseases affecting the gut. To study the role of innate immunity and gut microbiota in intestinal inflammation, colitis was induced by dextran sulfate sodium (DSS) in mice with severe combined immunodeficiency (SCID). Conventionally reared (microflora-colonized) SCID mice displayed severe inflammation like that seen in immunocompetent Balb/c mice, whereas only minor changes appeared in the intestinal mucosa of DSS-fed gnotobiotic germ-free SCID mice. The presence of microflora facilitates the inflammation in DSS-induced colitis that develops in immunodeficient SCID mice, that is, in the absence of T and B lymphocytes. Celiac disease, a chronic autoimmune small bowel disorder, afflicts genetically susceptible individuals with wheat gluten intolerance. We showed that, in contrast with any other food proteins, wheat gliadin and its peptic fragments activate mouse macrophages and human monocytes to produce proinflammatory cytokines through the nuclear factor-kappaB signaling pathway. Activation of innate immunity cells by food proteins or components from gut microbiota thus could participate in the impairment of intestinal mucosa and the development of intestinal and/or systemic inflammation. Metagenomic approaches are currently being used to decipher the genome of the microbiota (microbiome), and, in parallel, functional studies are being performed to analyze the effects of the microbiota on the host. Gnotobiological methods are an indispensable tool for studying the consequences of bacterial colonization. Animals used as models of human diseases can be maintained in sterile conditions (isolators used for germ-free rearing) and specifically colonized with defined microbes (including non-cultivable commensal bacteria). The effects of the germ-free state or the effects of colonization on disease initiation and maintenance can be observed in these models. Using this approach we demonstrated direct involvement of components of the microbiota in chronic intestinal inflammation and development of colonic neoplasia (i.e., using models of human inflammatory bowel disease and colorectal carcinoma). In contrast, a protective effect of microbiota colonization was demonstrated for the development of autoimmune diabetes in non-obese diabetic (NOD) mice. Interestingly, the development of atherosclerosis in germ-free apolipoprotein E (ApoE)-deficient mice fed by a standard low-cholesterol diet is accelerated compared with conventionally reared animals. Mucosal induction of tolerance to allergen Bet v1 was not influenced by the presence or absence of microbiota. Identification of components of the microbiota and elucidation of the molecular mechanisms of their action in inducing pathological changes or exerting beneficial, disease-protective activities could aid in our ability to influence the composition of the microbiota and to find bacterial strains and components (e.g., probiotics and prebiotics) whose administration may aid in disease prevention and treatment. Bacteroides, a predominant commensal bacteria in the gut, are thought to be responsible for the development of inflammatory bowel disease (IBD). In the present study, we examined whether or not bifidobacteria suppress B. vulgatus, a representative pathogenic Bacteroides species, in both the coculture system and the gnotobiotic murine model. As a result, Bifidobacterium infantis 1222 highly inhibited the growth of B. vulgatus in the coculture and also significantly suppressed the systemic antibody response raised by B. vulgatus colonizing the gut in gnotobiotic mice. Colonization of the mice by B. vulgatus increased the number of Peyer's patch (PP) cells bearing PNA (peanut agglutinin)+/anti-kappa+ phenotype, which represents plasma cell-like B cells. Moreover, treatment of those B. vulgatus-implanted mice with B. infantis 1222 abrogated such increase in the number of PNA+/anti-kappa+ cells. These results thus suggested that B. infantis 1222 protected the gut epithelial layer including the PP from being invaded by Bacteroides, thereby suppressing the systemic antibody response raised by Bacteroides. BACKGROUND: Specific pathogen-free (SPF), but not germfree (GF), interleukin (IL)-2-deficient (IL-2-/-) mice develop inflammatory bowel disease (IBD) at 10 to 15 weeks of age. Gnotobiotic IL-2-/- mice monocolonized with E. coli mpk develop IBD at 25 to 33 weeks of age but not B. vulgatus mpk, E. coli Nissle 1917, or mice cocolonized with both E. coli mpk and B. vulgatus. METHODS: To determine genes regulated by these commensal bacteria, host gene expression in the colon of 8-week-old IL-2-/- mice was compared by using microarrays and semiquantitative reverse-transcription polymerase chain reaction. Colonization with E. coli mpk/B. vulgatus or SPF microbiota altered the gene expression profile more profoundly than monocolonization with either B. vulgatus, E. coli mpk or E. coli Nissle indicating that the complexity of the gene expression pattern is influenced by the diversity of the microbiota. RESULTS: A small but distinct group of genes could be defined which might be associated with colitis development. Thus, 8 week old E. coli mpk IL-2-/- mice rone to colitis compared to E. coli Nissle, B. vulgatus and E. coli mpk/B. vulgatus IL-2-/- mice displayed a lower expression of the anti-inflammatory RegIII family genes such as RegIII[gamma] and pancreatitis associated protein (PAP) and peroxisome proliferator-activated receptor-[gamma] regulated genes such as adipsin and adiponectin. CONCLUSION: The increased expression of these genes in B. vulgatus colonized mice might be associated with prevention of E. coli mpk triggered colitis in E. coli mpkM/B. vulgatus IL-2-/- mice. |
322 | List chromosomes that have been linked to Arnold Chiari syndrome in the literature. | Chromosomes 1, 3, 5, 6, 8, 9, 12, 13, 15, 16, 18, 22, X and Y have been reported in association with Arnold Chiari syndrome in genetic linkage studies and individual case reports. | [23476832, 324229, 17103432, 15742475, 20101707, 11754060, 17190989, 6548367, 24359474, 20571508, 23620759, 2130777, 2798270, 23942271] | 429 | A combination of the congenital abnormalities, Müllerian duct aplasia, renal aplasia, and cervicothoracic somite dysplasia, is defined as the MURCS association. Various genetic defects have been described in the MURCS association so far, yet the unambiguous molecular basis of these disorders has not been established. We report the case of an 18-year-old woman who presented with primary amenorrhea, right kidney, Arnold-Chiari malformation, and Klippel-Feil syndrome. In addition, the patient showed the following unusual features: right ovarian and Skenes gland agenesis, cubitus valgus with hyperextension and decreased range of motion at elbows, and facial changes. Moreover, the performed DNA analysis showed interstitial duplication in chromosome 5 (5q35.1). In the duplicated region, there are genes whose function is not well known. It is thought that they have an influence on the early stages of development and their joining in the later period can lead to neoplastic disorders, especially leukemias. A variety of anomalies of the central nervous system are observed in trisomy 18. The present case describes an infant having a type II Arnold-Chiari malformation without spina bifida. One previous case of an Arnold-Chiari malformation was reported in trisomy 18 but that infant also had a lumbar meningomyelocoele. Abnormalities of cerebral gyration, hydrocephalus, and agenesis of the corpus callosum were also found in the present case. Chiari type I malformation (CMI; OMIM 118420) is narrowly defined when the tonsils of the cerebellum extend below the foramen magnum, leading to a variety of neurological symptoms. It is widely thought that a small posterior fossa (PF) volume, relative to the total cranial volume leads to a cramped cerebellum and herniation of the tonsils into the top of the spinal column. In a collection of magnetic resonance imagings (MRIs) from affected individuals and their family members, we measured correlations between ten cranial morphologies and estimated their heritability in these families. Correlations between bones delineating the PF and significant heritability of PF volume (0.955, P = 0.003) support the cramped PF theory and a genetic basis for this condition. In a collection of 23 families with 71 affected individuals, we performed a genome wide linkage screen of over 10,000 SNPs across the genome to identify regions of linkage to CMI. Two-point LOD scores on chromosome 15 reached 3.3 and multipoint scores in this region identified a 13 cM region with LOD scores over 1 (15q21.1-22.3). This region contains a biologically plausible gene for CMI, fibrillin-1, which is a major gene in Marfan syndrome and has been linked to Shprintzen-Goldberg syndrome, of which CMI is a distinguishing characteristic. Multipoint LOD scores on chromosome 9 maximized at 3.05, identifying a 40 cM region with LOD scores over 1 (9q21.33-33.1) and a tighter region with multipoint LOD scores over 2 that was only 8.5 cM. This linkage evidence supports a genetic role in Chiari malformation and justifies further exploration with fine mapping and investigation of candidate genes in these regions. Interstitial deletions of the middle portion of the long arm of chromosome 5 are relatively rare. So far, only 36 cases have been reported. Because of the repetitive banding pattern of this region, the extent and localization of the deleted segment has not been well characterized in the majority of reported cases. This has complicated attempts to establish a definite karyotype-phenotype correlation. We report a further case with a de novo interstitial deletion of the region 5q?15 to 5q?22 identified by standard karyotype analysis. The proband presented with failure to thrive, developmental delay, distinct craniofacial dysmorphic features, and associated structural anomalies (amongst them cleft palate, iris colobomata, and horseshoe kidney, which have previously been reported in 5q deletion cases). In addition, this child had an Arnold-Chiari type I malformation that required surgical decompression. FISH studies using BAC clones spanning the 5q15 to 5q22 region revealed that these were all present in both homologues. Use of more distal clones allowed delineation of the deleted region to 5q22.3q23.3 and to narrow down the breakpoints to approximately 200 kb. The 14 Mb deleted region contains about 60 genes but, with the possible exception of FBN2 and DMXL1, there are no obvious candidate genes for the specific components of the phenotype. This case illustrates the discrepancy between cytogenetic and molecular techniques in trying to delineate 5q interstitial deletions. Molecular studies need to be performed on these patients, to establish genotype-phenotype correlation and to understand the role and influence of genes in this region. Rubinstein-Taybi Syndrome (RSTS, OMIM 180849) is a rare condition, which in 65% of cases is caused by haploinsufficiency of CREBBP (cAMP response element binding protein binding protein) localized to 16p13.3. A small subset of RSTS cases caused by 16p13.3 microdeletions involving neighboring genes have been recently suggested to be a true contiguous gene syndrome called severe RSTS or 16p13.3 deletion syndrome (OMIM 610543). In the present report, we describe a case of a 2-year-old female with RSTS who, besides most of the typical features of RSTS has corpus callosum dysgenesis and a Chiari type I malformation which required neurosurgical decompression. CGH microarray showed a approximately 520.7 kb microdeletion on 16p13.3 involving CREBBP, ADCY9, and SRL genes. We hypothesize that the manifestations in this patient might be influenced by the haploinsufficiency for ADCY9 and SRL. A patient with microbrachycephaly, high forehead, long philtrum, thin upper lip, downturned corners of the mouth, low set ears with overlapping helix, fifth-finger clinodactyly, small hands and feet, bilateral transverse palmar crease, low total finger ridge count, hypotonia, severe growth and psychomotor delay, mild hypoplasia of corpus callosum, and Arnold-Chiari type 1 malformation is reported. The karyotype showed 46, XY, del(1)(q23q31.2). Coagulation factor V (F5, 1q23) and coagulation factor XIII (F13B, 1q31-q32.1) levels were normal. As expected, antithrombin III (AT3, 1q23-q25.1) serum level and activity were half of normal. We performed a review of the literature on proximal and intermediate deletion 1q syndrome, and we hypothesize the existence of only one 1q interstitial deletion syndrome, clinically characterized by ATIII deficiency. Pentasomy 49,XXXXY occurs in 1/85,000 newborn males. The origin of this particular form of aneuploidy is believed to be a result of consecutive nondisjunction events during maternal meiosis. Typical presentation consists of hypotonia, developmental delay, various dysmorphic features, and severe hypogenitalism. A 13-year-old with pentasomy 49,XXXXY and a Chiari type 1 malformation with an associated cervical syrinx is presented. Chiari Type I Malformation (CMI) is characterized by displacement of the cerebellar tonsils below the base of the skull, resulting in significant neurologic morbidity. Although multiple lines of evidence support a genetic contribution to disease, no genes have been identified. We therefore conducted the largest whole genome linkage screen to date using 367 individuals from 66 families with at least two individuals presenting with nonsyndromic CMI with or without syringomyelia. Initial findings across all 66 families showed minimal evidence for linkage due to suspected genetic heterogeneity. In order to improve power to localize susceptibility genes, stratified linkage analyses were performed using clinical criteria to differentiate families based on etiologic factors. Families were stratified on the presence or absence of clinical features associated with connective tissue disorders (CTDs) since CMI and CTDs frequently co-occur and it has been proposed that CMI patients with CTDs represent a distinct class of patients with a different underlying disease mechanism. Stratified linkage analyses resulted in a marked increase in evidence of linkage to multiple genomic regions consistent with reduced genetic heterogeneity. Of particular interest were two regions (Chr8, Max LOD = 3.04; Chr12, Max LOD = 2.09) identified within the subset of "CTD-negative" families, both of which harbor growth differentiation factors (GDF6, GDF3) implicated in the development of Klippel-Feil syndrome (KFS). Interestingly, roughly 3-5% of CMI patients are diagnosed with KFS. In order to investigate the possibility that CMI and KFS are allelic, GDF3 and GDF6 were sequenced leading to the identification of a previously known KFS missense mutation and potential regulatory variants in GDF6. This study has demonstrated the value of reducing genetic heterogeneity by clinical stratification implicating several convincing biological candidates and further supporting the hypothesis that multiple, distinct mechanisms are responsible for CMI. A rare case of syringomyelia associated with Arnold-Chiari malformation, primary IgA deficiency and sex chromosomal abnormality is reported. A 26-year-old Ethiopian black male was admitted with a complaint of hypalagesia of his left arm and face for 10 years. Neurological examination on admission revealed dissociated sensory loss of his left arm and face. Mild motor weakness of his hand and rotatory nystagmus on left gaze were also noticed. Plain craniogram of lateral view showed small posterior cranial fossa with low positioned inion and platybasia. MRI with T1-weighted images in sagittal plane revealed tonsillar herniation reaching C1 and syrinx extending from C2 to lumbar region. Although no episode of infectious disease nor allergy were experienced, blood analysis disclosed low serum level of IgA (7 mg/dl). The values of other immunoglobulins were within normal range. IgA in saliva was not detected, too. According to the clinical history and symptoms, a diagnosis is of primary asymptomatic IgA deficiency was obtained. Karyotype analysis showed inversion of Y chromosome. In an attempt to avoid anaphylactic shock on blood transfusion in a patient with IgA deficiency, autologous blood was prepared before surgery. Decompressive craniectomy of the posterior fossa with posterior arch of C1 and C2 was performed together with syringosubarachnoid shunt at Th 6-7 level. Postoperative course was successful and slight improvement of sensory disturbance was obtained. No respiratory or wound infection was occurred. The association of these three anomalies is very rare and genetical relationship is not known. From surgical point of view, it is conceivable that preoperative management in a case of asymptomatic IgA deficiency is uneventful. The clinical features and morphological findings in 31 Japanese infants with trisomy 18 are presented. The majority were small-for-date infants. There was no sex predominance in our series, as opposed to male:female ratios of 1:3 reported in the literature. The average age at death was greater in females than in males. Cardiovascular anomalies were consistently present; ventricular septar defect and patent ductus arteriosus being the most common malformations. Various other internal malformations including the Arnold-Chiari malformation were observed. The first child (proband) of nonconsanguineous Caucasian parents underwent genetic investigation because she was affected with congenital choanal atresia, heart defects and kidney hyposplasia with mild transient renal insufficiency. The direct DNA sequencing after PCR of the CHD7 gene, which is thought to be responsible for approximately 60-70% of the cases of CHARGE syndrome/association, found no mutations. The cytogenetic analysis (standard GTG banding karyotype) revealed the presence of extrachromosomal material on 10q. The chromosome analysis was completed with array CGH (30 kb resolution), MLPA and FISH, which allowed the identification of three 6p regions (6p.25.3p23 × 3): 2 of these regions are normally located on chromosome 6, and the third region is translocated to the long arm of chromosome 10. The same chromosomal rearrangement was subsequently found in the father, who was affected with congenital ptosis and progressive hearing loss, and in the proband's sister, the second child, who presented at birth with choanal atresia and congenital heart defects. The mutated karyotypes, which were directly inherited, are thought to be responsible for a variable phenotype, including craniofacial dysmorphisms, choanal atresia, congenital ptosis, sensorineural hearing loss, heart defects, developmental delay, and renal dysfunction. Nevertheless, to achieve a complete audiological assessment of the father, he underwent further investigation that revealed an increased level of the coagulation factor XIII (300% increased activity), fluctuating levels of fibrin D-dimer degradation products (from 296 to 1,587 ng/ml) and a homoplasmic mitochondrial DNA mutation: T961G in the MTRNR1 (12S rRNA) gene. He was made a candidate for cochlear implantation. Preoperative high-resolution computed tomography and magnetic resonance imaging of the temporal bone revealed the presence of an Arnold-Chiari malformation type I. To the best of our knowledge, this study is the second report on partial 6p trisomy that involves the 10q terminal region. Furthermore, we report the first case of documented Arnold-Chiari malformation type I and increased factor XIII activity associated with 6p trisomy. We present a comprehensive report of the familial cases and an exhaustive literature review. |
323 | Which translocation is the hallmark of Ewing sarcoma? | Tumours defined as Ewing sarcoma (ES) constitute a group of highly malignant neoplasms that most often affect children and young adults in the first 2 decades of life. The EWS/Fli-1 fusion gene, a product of the translocation t(11;22) (q24; 12), is detected in 95% of ES patients | [16864960, 21422656, 21653923, 25401475, 24124617, 22266186, 23145994, 24974828, 15274413, 6416622, 10030577, 16083345, 22240531, 15919668, 22742646, 8644855, 18971581, 21942527] | 430 | Ewing's sarcoma (ES) is a highly malignant tumor composed of uniform small round cells. Recently, a single biologic entity, Ewing's sarcoma family of tumors (ESFT) has been accepted. The entity includes ES, extraskeletal Ewing's sarcoma (EES) and primitive neuroectodermal tumor (PNET). ESFT cells have immunoreactivity for CD99, an antigen determined by the MIC2 gene. Most ESFT has the (11;22) (q24;q12) translocation. The translocation results in the fusion of the EWS gene with the transcription factor gene FLI1 which has been considered a hallmark of ESFT. We present an extremely unusual case with ESFT in a spinal nerve root mimicking a neurogenic dumbbell tumor. A male aged 20 years noticed pain in his right buttock. Magnetic resonance imaging (MRI) revealed a mass in the right L5/S intervertebral foramen and the lesions in the sacrum. Surgery was performed with a presumptive diagnosis of a nerve sheath tumor. At surgery, the tumor was located in the right L5 nerve root sleeve. The sacral lesions were observed closely. At one month after surgery, radiologically multiple lesions were detected in the pelvic bones. Microscopically the lesions from the root and ilium were composed of small round cells immunoreactive for CD99. Reverse transcription-polymerase chain reaction detected transcripts resulting from the fusion of the EWS gene with FLI1 genes in the iliac lesion. Immunoreactivity for CD99 and detection of the EWS-FLI1 hybrid transcripts are important for the correct diagnosis of ESFT arising in an unusual location. Ewing/PNET (peripheral neuroepithelioma) tumors are rare aggressive bone sarcomas occurring in young people. Rare-disease clinical trials can require global collaborations and many years. In vivo models that as accurately as possible reflect the clinical disease are helpful in selecting therapeutics with the most promise of positive clinical impact. Human Ewing/PNET sarcoma cell lines developed over the past 45 years are described. Several of these have undergone genetic analysis and have been confirmed to be those of Ewing/PNET sarcoma. The A673 Ewing sarcoma line has proven to be particularly useful in understanding the biology of this disease in the mouse. The chromosomal translocation producing the EWS/FLI1 fusion transcript characterizes clinical Ewing sarcoma. Cell lines that express this genetic profile are confirmed to be those of Ewing sarcoma. The A673 Ewing sarcoma line grows in culture and as a xenograft in immunodeficient mice. The A673 model has been used to study Ewing sarcoma angiogenesis and response to antiangiogenic agents. Many Ewing sarcoma clinical specimens express the cell surface protein endosialin. Several Ewing sarcoma cell lines, including the A673 line, also express cell surface endosialin when grown as subcutaneous tumor nodules and as disseminated disease; thus the A673 is a useful model for the study of endosialin biology and endosialin-directed therapies. With the advent of tools that allow characterization of clinical disease to facilitate optimal treatment, it becomes imperative, especially for rare tumors, to develop preclinical models reflecting disease subsets. Ewing PNET sarcomas are a rare disease where models are available. BACKGROUND: Chromosomal translocations generating oncogenic transcription factors are the hallmark of a variety of tumors, including many sarcomas. Ewing sarcoma family of tumors (ESFTs) are characterized by the t(11;22)(q24;q12) translocation that generates the Ewing sarcoma breakpoint region 1 and Friend leukemia virus integration 1 (EWS-FLI1) fusion transcription factor responsible for the highly malignant phenotype of this tumor. Although continued expression of EWS-FLI1 is believed to be critical for ESFT cell survival, a clinically effective small-molecule inhibitor remains elusive likely because EWS-FLI1 is a transcription factor and therefore widely felt to be "undruggable." METHODS: We developed a high-throughput screen to evaluate more than 50 000 compounds for inhibition of EWS-FLI1 activity in TC32 ESFT cells. We used a TC32 cell-based luciferase reporter screen using the EWS-FLI1 downstream target NR0B1 promoter and a gene signature secondary screen to sort and prioritize the compounds. We characterized the lead compound, mithramycin, based on its ability to inhibit EWS-FLI1 activity in vitro using microarray expression profiling, quantitative reverse transcription-polymerase chain reaction, and immunoblot analysis, and in vivo using immunohistochemistry. We studied the impact of this inhibition on cell viability in vitro and on tumor growth in ESFT xenograft models in vivo (n = 15-20 mice per group). All statistical tests were two-sided. RESULTS: Mithramycin inhibited expression of EWS-FLI1 downstream targets at the mRNA and protein levels and decreased the growth of ESFT cells at half maximal inhibitory concentrations between 10 (95% confidence interval [CI] = 8 to 13 nM) and 15 nM (95% CI = 13 to 19 nM). Mithramycin suppressed the growth of two different ESFT xenograft tumors and prolonged the survival of ESFT xenograft-bearing mice by causing a decrease in mean tumor volume. For example, in the TC32 xenograft model, on day 15 of treatment, the mean tumor volume for the mithramycin-treated mice was approximately 3% of the tumor volume observed in the control mice (mithramycin vs control: 69 vs 2388 mm(3), difference = 2319 mm(3), 95% CI = 1766 to 2872 mm(3), P < .001). CONCLUSION: Mithramycin inhibits EWS-FLI1 activity and demonstrates ESFT antitumor activity both in vitro and in vivo. Tumours defined as Ewing sarcoma (ES) constitute a group of highly malignant neoplasms that most often affect children and young adults in the first 2 decades of life. The EWS/Fli-1 fusion gene, a product of the translocation t(11;22) (q24; 12), is detected in 95% of ES patients. Recently, it was validated that cells emit a heterogeneous mixture of vesicular, organelle-like structures (microvesicles, MVs) into their surroundings including blood and body fluids, and that these MVs contain a selected set of tumor-related proteins and high levels of mRNAs and miRNAs. In this present study, we detected the Ewing sarcoma-specific EWS/Fli-1 mRNA in MVs from the culture medium of ES cell lines carrying t(11;22) (q24; 12). Also, we detected this fusion gene in approximately 40% of the blood samples from mice inoculated with xenografts of TC135 or A673 cells. These findings indicate the EWS/Fli-1 mRNA in MVs might be a new non-invasive diagnostic marker for specific cases of Ewing sarcoma. BACKGROUND: Ewing's sarcoma is a malignancy characterized by a specific 11:22 chromosomal translocation which generates a novel EWS-FLI1 fusion protein functioning as an aberrant transcription factor. In the present study, we have further characterized the junction region of the EWS-FLI1 fusion protein. METHODS: In-silico model of EWS-FLI1 fusion protein was analysed for ligand binding sites, and a putative region (amino acid (aa) 251-343 of the type 1 fusion protein) in the vicinity of the fusion junction was cloned and expressed using bacterial expression. The recombinant protein was characterized by Circular Dichroism (CD). We then expressed aa 251-280 ectopically in Ewing's sarcoma cell-line and its effect on cell proliferation, tumorigenicity and expression of EWS-FLI1 target genes were analysed. RESULTS: Our modelling analysis indicated that Junction region (aa 251-343) encompasses potential ligand biding sites in the EWS-FLI1 protein and when expressed in bacteria was present as soluble form. Ectopically expressing this region in Ewing's sarcoma cells inhibited tumorigenicity, and EWS-FLI1 target genes indicating a dominant negative biological effect. CONCLUSIONS: Junction region can be exploited further as target for drug development in future to specifically target EWS-FLI1 in Ewing's Sarcoma. Translocations involving ETS-transcription factors, most commonly leading to the EWSR1-FLI1 fusion protein, are the hallmark of Ewing sarcoma. Despite knowledge of this driving molecular event, an effective therapeutic strategy is lacking. To test potential treatment regimes, we established a novel Ewing sarcoma zebrafish engraftment model allowing time-effective, dynamic quantification of Ewing sarcoma progression and tumour burden in vivo, applicable for screening of single and combined compounds. In Ewing sarcoma the tumour-suppressor gene TP53 is commonly found to be wild-type, thus providing an attractive target for treatment. Here, we study TP53 wild-type (EW7, CADO-ES1 and TC32) and TP53-deleted (SK-N-MC) Ewing sarcoma cell lines to investigate the potentiating effect of p53 reactivation by Nutlin-3 on treatment with YK-4-279 to block transcriptional activity of EWSR1-FLI1 protein. Blocking EWSR1-FLI1 transcriptional activity reduced Ewing sarcoma tumour cell burden irrespective of TP53 status. We show that simultaneous YK-4-279 treatment with Nutlin-3 to stabilize p53 resulted in an additive inhibition of TP53 wild-type Ewing sarcoma cell burden, whilst not affecting TP53-deleted Ewing sarcoma cells. Improved inhibition of proliferation and migration by combinatorial treatment was confirmed in vivo by zebrafish engraftments. Mechanistically, both compounds together additively induced apoptosis of tumour cells in vivo by engaging distinct pathways. We propose reactivation of the p53 pathway in combination with complementary targeted therapy by EWSR1-FLI1 transcriptional activity disruption as a valuable strategy against p53 wild-type Ewing sarcoma. Primitive neuroectodermal tumors are in the Ewing's sarcoma family of tumors and are composed of small round cells. Because of their rare occurrence, optimal therapy is challenging, particularly if they occur in the head and neck. Diagnosis is based on history, immunostaining with at least 2 neural markers, ultrastructural examination, and evidence of an abnormal t(11;22)(q24;q12) translocation as the hallmark for the Ewing's sarcoma family. The prognosis in general is poor because of overt metastasis at the time of diagnosis. Of 27 reported patients with primitive neuroectodermal tumors of the head and neck, 23 were less than 20 years of age. Most patients presented with a tumor in the nasal cavity, paranasal sinuses, or neck. Symptoms developed rapidly (3.6 months, on average), and a lethal outcome occurred in 9 patients. This highly malignant tumor requires an aggressive combination of radical resection, chemotherapy, and radiotherapy. A close follow-up with regular radiographic examination for at least 5 years is mandatory. PURPOSE: To describe a patient with metastasis of Ewing sarcoma to the choroid and the molecular genetics of the tumor. METHODS: A 26-year-old woman with metastatic Ewing sarcoma developed large choroidal masses in the left eye and died 2 months later. Autopsy of the eyes was performed. Dual-color fluorescent in situ hybridization was used to detect genetic alteration in the ocular tumor with EWS and FLI-1 probes. RESULTS: Histopathology confirmed choroidal metastatic Ewing sarcoma. Molecular analysis showed chromosomal translocation t(11;22)(q24;q12) or EWS/FLI-1 rearrangement in the malignant cells of the eye. CONCLUSIONS: Ewing sarcoma can rarely metastasize to the uvea. Molecular detection of the t(11;22)(q24;q12) translocation in Ewing sarcoma is valuable in the differential diagnosis of small round cell tumors. BACKGROUND: Ewing sarcoma is extremely rare in people from East and Southeast Asia. METHODS: The records of 12 patients diagnosed with primary Ewing sarcoma and treated at our institution from 1997 to 2009 were retrospectively reviewed. RESULTS: There were seven male and five female patients and their mean age at diagnosis was 22 years (range, 12-48 years). Two patients (16.7%) had distant metastasis at diagnosis. The primary tumor sites were the trunk in seven patients (58.3%) and the extremities in five patients (41.7%). Eleven patients received neoadjuvant chemotherapy followed by wide excision surgery, and then adjuvant chemotherapy. One patient received only chemotherapy without surgical intervention due to poor cardiac and pulmonary function. At a mean follow-up of 33 months, the 2-year overall survival rate (OS) was 45.5%. Distant metastasis was the only statistically significant prognostic factor of OS in our study. The 2-year OS rates of patients with lung metastasis and without lung metastasis were 0% and 42.9%, respectively (p = 0.021). The t(11;22)(q24:q12) translocation was present in all patients in our series. CONCLUSION: We confirmed that distant metastases is highly predictive of a poor outcome, and that the t(11;22)(q24:q12) translocation was present in all patients in our series. EWS-Fli1, a fusion gene resulting from a chromosomal translocation t(11;22, q24;q12) and found in Ewing sarcoma and primitive neuroectodermal tumors, encodes a transcriptional activator and promotes cellular transformation. However, the precise biological functions of its products remain unknown. To investigate the role of EWS-Fli1 in cell growth signaling, we transfected Ewing sarcoma TC-135 cells with short interfering RNAs for EWS-Fli1. EWS-Fli1 knockdown reduced cell growth and platelet-derived growth factor (PDGF)-BB-induced activation of the growth signaling enzymes. Interestingly, phospholipase D2 (but not the PDGF-BB receptor) showed marked down-regulation in the EWS-Fli1-knocked down TC-135 cells compared with the control cells. In Ewing sarcoma TC-135 cells, the PDGF-BB-induced phosphorylation of growth signaling involving extracellular signal-regulated kinase, Akt, p70S6K, and the expression of cyclin D3 were markedly inhibited by transfection with short interfering RNA phospholipase (PL)-D2. The PDGF-BB-induced activation of growth signaling was also suppressed by 1-butanol, which prevents the production of phosphatidic acid by phospholipase D (but not by t-butyl alcohol), thereby implicating PLD2 in PDGF-BB-mediated signaling in TC-135 cells. These results suggest that EWS-Fli1 may play a role in the regulation of tumor proliferation-signaling enzymes via PLD2 expression in Ewing sarcoma cells. The hallmark of Ewing's sarcoma (EWS) is a translocation--t(11;22)(q24;q12)--that most frequently results in the EWS/FLI1 aberrant chimeric gene. Because EWS afflicts young patients, it stands out among the diverse sarcoma subtypes. The frontline, standard-of-care cytotoxic chemotherapy regimens produce minimal benefit in patients with metastases at presentation or those with relapsed disease. While the outcomes of chemorefractory EWS patients are generally poor, recent developments have led to the promising use of targeted therapy. Specifically, inhibition of insulin-like growth factor 1 receptor (IGF1R) signaling and the mammalian target of rapamycin (mTOR) pathways has emerged as a targeted therapy in EWS, with select patients experiencing dramatic therapeutic responses. However, targeted therapies in general, and these responders in particular, are faced with the ultimate conundrum of eventual resistance. To optimize response, combining IGF1R and mTOR inhibitor-based regimens with chemotherapy in the upfront setting in newly diagnosed high-risk EWS may clarify the true benefit of IGF1R inhibitors in these patients. Another option is to explore novel targeted multikinase inhibitors and poly(ADP-ribose) polymerase (PARP) inhibitors, which have experienced a surge in supporting preclinical data. Drugs inhibiting the downstream targets of EWS/FLI1 are also in preclinical development. However, ultimately, the underlying biomarker correlates of resistance and response must be delineated along with ways to overcome them. Novel agents, together with integration of advances in multimodal approaches (including surgery and radiation), as well as offering targeted therapies early in the disease course represent new strategies for confronting the challenges of EWS. Approximately one-third of sarcomas contain specific translocations. Ewing sarcoma is the prototypical member of this group of sarcomas; it was the first to be recognized pathologically as a singular entity and to have its signature translocation defined cytogenetically, which led to the identification of its key driver alteration, the EWS-FLI1 gene fusion that encodes this aberrant, chimeric transcription factor. We review recent progress in selected areas of Ewing sarcoma research, including the application of genome-wide chromatin immunoprecipitation analyses, to provide a comprehensive view of the EWS-FLI1 target gene repertoire, the identification of EWS-FLI1 target genes that may also point to therapeutically targetable pathways, and data from model systems as they relate to the elusive cell of origin of Ewing sarcoma and its possible similarities to mesenchymal stem cells. |
324 | Is invasion and metastasis one of the hallmarks of cancer? | Yes, invasion and metastasis are one of the so-called hallmarks of cancer. | [19662202] | 431 | Malignant mesothelioma (MM) is a malignant tumor derived from mesothelial cells, native cells of the body cavities. Exposure to asbestos is the most strongly established etiologic factor, predominantly for the most common disease form, pleural mesothelioma. The pathogenesis of MM involves the accumulation of extensive cytogenetic changes, as well as cancer-related phenotypic alterations that facilitate tumor cell survival, invasion and metastasis. This review presents current knowledge regarding the biological characteristics of this disease that are linked to the so-called hallmarks of cancer. In addition, data suggesting that the anatomic site (solid tumor vs. effusion) affects the expression of metastasis-associated and regulatory molecules in MM are presented. Finally, recent work in which high-throughput methodology has been applied to MM research is reviewed. The data obtained in the reviewed research may aid in defining new prognostic markers and therapeutic targets for this aggressive disease in the future. |
325 | Is it possible to detect survivin protein expression in normal human adult tissues? | No. Survivin is an inhibitor of apoptosis that is undetectable in normal differentiated tissues of adult human. | [18856066, 17382535, 20520718, 23132836, 21371446, 17204284, 15990723, 17163847, 22930255, 12671708, 18376799, 20514400, 16360419, 15195112, 17611626, 14719083, 10626797, 16619249, 18425079, 15138808] | 432 | Fragile histidine triad (FHIT) gene, a candidate tumor suppressor gene located at 3p14.2, has been shown to be involved in carcinogenesis of many human tissues, including digestive tract tissues. However, the expression and role of FHIT in the initiation and the development of the colorectal cancer (CRC) are poorly understood. In our present study, we have demonstrated that the FHIT gene exhibits significantly decreased expression in human CRC compared to colorectal adenoma and normal colorectal tissue by tissue microarray (TMA). The positive of FHIT gene expression in normal colorectal tissue, adenoma and adenocarcinoma were 93.75%, 68.75% and 46.25%, respectively. We showed that decreased FHIT expression was significantly correlated with the progression of colorectal carcinoma (P<0.05) as well as differentiation and lymph node metastasis (P<0.05). Two somatic mutations in the FHIT gene were also detected in human CRC. The presence of these mutations correlated significantly with decreased FHIT expression in the human CRC. In addition, we identified decreased FHIT expression resulting in apoptosis inhibition and decreasing apoptosis associated with abnormal levels of some pro- and anti-apoptotic proteins (Bax, Bcl-2 and Survivin) by TUNEL and TMA. Our results demonstrated that the mutation in the FHIT gene significantly reduced FHIT expression in human CRC. Both TUNEL and TMA experiments demonstrated significantly inhibited apoptosis by down-regulation of Bax and up-regulation of Survivin and Bcl-2. Collectively, these studies identify the mechanism by which an important tumor suppressor gene, FHIT, inactivated specifically in human CRC, and contributes to our understanding of the mechanism of colorectal carcinogenesis. A cardinal feature of malignant melanoma is its metastatic propensity. An incomplete view of the genetic events driving metastatic progression has been a major barrier to rational development of effective therapeutics and prognostic diagnostics for melanoma patients. In this study, we conducted global genomic characterization of primary and metastatic melanomas to examine the genomic landscape associated with metastatic progression. In addition to uncovering three genomic subclasses of metastastic melanomas, we delineated 39 focal and recurrent regions of amplification and deletions, many of which encompassed resident genes that have not been implicated in cancer or metastasis. To identify progression-associated metastasis gene candidates, we applied a statistical approach, Integrative Genome Comparison (IGC), to define 32 genomic regions of interest that were significantly altered in metastatic relative to primary melanomas, encompassing 30 resident genes with statistically significant expression deregulation. Functional assays on a subset of these candidates, including MET, ASPM, AKAP9, IMP3, PRKCA, RPA3, and SCAP2, validated their pro-invasion activities in human melanoma cells. Validity of the IGC approach was further reinforced by tissue microarray analysis of Survivin showing significant increased protein expression in thick versus thin primary cutaneous melanomas, and a progression correlation with lymph node metastases. Together, these functional validation results and correlative analysis of human tissues support the thesis that integrated genomic and pathological analyses of staged melanomas provide a productive entry point for discovery of melanoma metastases genes. Polycomb group proteins are essential regulators of stem cell function during embryonic development and in adult tissue homeostasis. Bmi1, a key component of the Polycomb Repressive Complex 1, is highly expressed in undifferentiated neural stem cells (NSC) as well as in several human cancers including high-grade gliomas--highly aggressive brain tumors. Using a conditional gene activation approach in mice, we show that overexpression of Bmi1 induces repressive epigenetic regulation of the promoter of Survivin, a well-characterized antiapoptotic protein. This phenomenon is cell type-specific and it leads to apoptotic death of progenitor cells exclusively upon commitment toward a neuronal fate. Moreover, we show that this is triggered by increased oxidative stress-induced DNA damage. In contrast, undifferentiated NSC as well as glioma-initiating cells display an open chromatin configuration at the Survivin promoter and do not undergo apoptotic death. These findings raise the possibility that normal and neoplastic stem cells depend on the same mechanism for surviving the hyperproliferative state induced by increased Bmi1 expression. We studied the effects of AZD1152, an Aurora B kinase inhibitor, on Burkitt's lymphoma (BL) and Hodgkin's lymphoma (HL) in human tissues and cell cultures and in a murine xenograft model of lymphoma. Aurora kinase A and B levels were assessed by RT-PCR and immunohistochemistry. They were aberrantly expressed in BL and HL cell lines, and in lymph nodes from patients with BL and HL. Next, activation of the Aurora B promoter was detected by reporter gene assays. The promoter activity of Aurora B kinase was high in BL cell lines and the Aurora B promoter contained a positive regulatory region between -74 and -104 from the transcription initiation site. AZD1152-hQPA had antiproliferative effects in the BL and HL cell lines studied; inhibited the phosphorylation of histone H3 and retinoblastoma proteins, and resulted in cells with > 4N DNA content. AZD1152-hQPA induced caspase-dependent apoptosis of some cell lines, demonstrated by loss of mitochondrial membrane potential, activation of caspase-9, followed by activation of caspase-3. This effect was accompanied by the inhibition of survivin expression. In vivo efficacy was determined in NOD/SCID/γc(null) mice implanted with the Ramos human BL cell line. AZD1152 had anti-tumour effects in this murine xenograft model. There preclinical data suggest that the inhibition of Aurora B kinase is a potentially useful therapeutic strategy in BL and HL. Survivin is a member of the inhibitor apoptosis family that is overexpressed in many malignancies. It has five known alternative splice forms, some of which differ in their antiapoptotic properties and expression levels in human cancers. Here we describe a novel donor splice site (DSS), 2B+32 DSS, which is used in conjunction with survivin alternative exon 2B, resulting in the inclusion of 32 additional nucleotides from intron 2 at the 3' end of this exon. Sequence analysis showed that both the classical exon 2B DSS and 2B+32 are provided by an Alu sequence, which is inserted in intron 2 downstream of a functional acceptor splice site, leading to the exonization of part of the repetitive element. Minor transcripts including the 2B+32 alternative exon, or retaining the whole intronic region comprised between exons 2B and 3, were detected in several human cell lines and in some human tissues. Survivin 2B+32 containing variants acquire a premature stop codon (PTC) and may therefore be degraded by the nonsense mediated decay pathway. The implication of these novel isoforms, as well as other PTC+ survivin variants, in the overall regulation of survivin expression is discussed. Sequence analysis of intron 2 which contains the Alu Y element was performed on different primate species in order to trace its insertion and exonization during primate evolution. Survivin is a member of the inhibitor of apoptosis (IAP) family, and is also involved in the regulation of cell division. Survivin is widely expressed in foetal tissues and in human cancers, but generally not in normal adult tissue. This study examined the expression of surviving protein in a series of 293 cases of invasive primary breast carcinoma. Survivin immunoreactivity was assessed using two different polyclonal antibodies, and evaluated semiquantitatively according to the percentage of cells demonstrating distinct nuclear and/or diffuse cytoplasmic staining. Overall, 60% of tumours were positive for survivin: 31% demonstrated nuclear staining only, 13% cytoplasmic only, and 16% of tumour cells demonstrated both nuclear and cytoplasmic staining. Statistical analysis revealed that survivin expression was independent of patient's age, tumour size, histological grade, nodal status, and oestrogen receptor status. In multivariate analysis, nuclear survivin expression was a significant independent prognostic indicator of favourable outcome both in relapse-free and overall survival (P<0.001 and P=0.01, respectively). In conclusion, our results show that survivin is frequently overexpressed in primary breast cancer. Nuclear expression is most common and is an independent prognostic indicator of good prognosis. Survivin is an inhibitor of apoptosis protein and regulates the cell cycle in the G2/M phase. Survivin is expressed during embryonic and fetal development, selectively over-expressed in common human cancers and completely down-regulated in normal adult tissue. This work was aimed at studying the expression of the survivin homologues and their subcellular distribution in fetal and normal adult tissues of rat. Survivin expression was evaluated by immunohistochemistry in formalin-fixed, paraffin-embedded tissue sections of fetal and normal adult tissues of rat using the polyclonal serum SUR12A-CFI. This serum demonstrated intense positive survivin staining in adult kidney, ovary and oviduct, and a variable expression in different fetal organs, with particularly intense expression detected in the adrenal gland, liver, stomach, small intestine, colon, kidney and skin. In both fetal and adult tissues, the expression was predominantly cytoplasmic. It was concluded that survivin was abundantly and prominently expressed during fetal development in rat and that the polyclonal anti-human survivin antibody SUR12A-CFI is reactive with rat survivin. Hepatocellular carcinoma (HCC) is known to be resistant to chemotherapy. Survivin, a member of the inhibitor of apoptosis proteins, is overexpressed in most cancers but is absent in most normal adult tissue. The aim of this study was to investigate whether expression of survivin contributes to resistance to cisplatin-induced apoptosis. We confirmed induction of survivin expression in hepatoma in the N-diethylnitrosamine (DEN) induced rat and in the rat hepatoma cell line (K-251). We examined cell proliferation after treatment with cisplatin (CDDP) in the presence and absence of siRNA or the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 to suppress survivin or PI3K/Akt, respectively. Survivin was expressed in DEN-induced rat HCC with RT-PCR and Western blotting. Expression of survivin was observed primary in the nuclei and in the cytoplasm with immunohistochemistry. However, survivin was not detected in non-tumor tissues. Expression of survivin was also observed primarily in the nuclei and in the cytoplasm of the K-251 rat hepatoma cell line. CDDP induced survivin expression, which was blocked by siRNA. LY294002 also attenuated survivin expression induced by CDDP. Our results indicate that survivin expression via PI3K contributes to resistance to CDDP-induced apoptosis in a rat hepatoma cell line. BACKGROUND: Gene expression profiling has revolutionized our ability to molecularly classify primary human tumors and significantly enhanced the development of novel tumor markers and therapies; however, progress in the diagnosis and treatment of melanoma over the past 3 decades has been limited, and there is currently no approved therapy that significantly extends lifespan in patients with advanced disease. Profiling studies of melanoma to date have been inconsistent due to the heterogeneous nature of this malignancy and the limited availability of informative tissue specimens from early stages of disease. METHODOLOGY/PRINCIPLE FINDINGS: In order to gain an improved understanding of the molecular basis of melanoma progression, we have compared gene expression profiles from a series of melanoma cell lines representing discrete stages of malignant progression that recapitulate critical characteristics of the primary lesions from which they were derived. Here we describe the unsupervised hierarchical clustering of profiling data from melanoma cell lines and melanocytes. This clustering identifies two distinctive molecular subclasses of melanoma segregating aggressive metastatic tumor cell lines from less-aggressive primary tumor cell lines. Further analysis of expression signatures associated with melanoma progression using functional annotations categorized these transcripts into three classes of genes: 1) Upregulation of activators of cell cycle progression, DNA replication and repair (CDCA2, NCAPH, NCAPG, NCAPG2, PBK, NUSAP1, BIRC5, ESCO2, HELLS, MELK, GINS1, GINS4, RAD54L, TYMS, and DHFR), 2) Loss of genes associated with cellular adhesion and melanocyte differentiation (CDH3, CDH1, c-KIT, PAX3, CITED1/MSG-1, TYR, MELANA, MC1R, and OCA2), 3) Upregulation of genes associated with resistance to apoptosis (BIRC5/survivin). While these broad classes of transcripts have previously been implicated in the progression of melanoma and other malignancies, the specific genes identified within each class of transcripts are novel. In addition, the transcription factor NF-KB was specifically identified as being a potential "master regulator" of melanoma invasion since NF-KB binding sites were identified as consistent consensus sequences within promoters of progression-associated genes. CONCLUSIONS/SIGNIFICANCE: We conclude that tumor cell lines are a valuable resource for the early identification of gene signatures associated with malignant progression in tumors with significant heterogeneity like melanoma. We further conclude that the development of novel data reduction algorithms for analysis of microarray studies is critical to allow for optimized mining of important, clinically-relevant datasets. It is expected that subsequent validation studies in primary human tissues using such an approach will lead to more rapid translation of such studies to the identification of novel tumor biomarkers and therapeutic targets. We previously reported that prostate derived Ets transcription factor (PDEF) is a breast tumor-associated molecule. To obtain further insights into PDEF expression in other human tumor types, a cDNA library database from human adult normal and tumor tissues was compiled and searched for PDEF distribution. The results showed that PDEF is present at relative higher frequencies in the cDNA libraries from brain, breast, lung and ovarian tumors in comparison to those from the corresponding normal tissues. RT/PCR analysis of PDEF expression in ovarian tumors confirmed that PDEF is expressed in 36 out of 51 (71%) ovarian tumors. Further comparison of the distribution of PDEF with other widely recognized cancer-associated molecules showed that PDEF has more restricted distributions than Her-2/neu, Bcl-2, survivin or telomerase in cDNA libraries from normal human tissues and more increased distribution than Her-2/neu, CA-125, Bcl-2, survivin and telomerase in cDNA libraries from brain (except survivin), breast, lung and ovarian tumors. These data together show a better tumor-association for PDEF and suggest that PDEF is a more suitable target for developing specific cancer therapies. Recently, a novel antiapoptosis gene, i.e., survivin, was identified as a structurally unique member of the inhibitor of apoptosis protein family. Survivin expression is turned off during fetal development and not found in non-neoplastic adult human tissues but is again turned on in the most common human cancers. The antiapoptotic properties of survivin might provide a significant growth advantage in tumors and possibly also contribute to chemoresistance of cancer. Therefore, we analyzed the expression of survivin in human renal cell carcinomas (RCCs), known to be largely resistant to chemotherapy. Northern blot analysis and RT-PCR revealed survivin expression in newly established RCC cell lines (n = 11) of all major histological types. Moreover, we identified two novel splice variants of survivin, lacking exon 3 (survivin-deltaEx3) or retaining a part of intron 2 as a cryptic exon (survivin-2B). Both sequence alterations cause marked changes in the structure of the corresponding proteins, including structural modifications of the baculovirus inhibitor of apoptosis protein repeat domain. The role of the novel isoforms in the regulation of apoptosis was assessed in transfection experiments, showing conservation of antiapoptotic properties for survivin-deltaEx3 and a markedly reduced antiapoptotic potential for survivin-2B. In conclusion, our observations suggest a complex regulatory balance between the different isoforms of survivin, which might determine the response to proapoptotic stimuli, not only in human RCCs but also in fetal tissues and other types of cancer. Inhibition of apoptosis is a critical step in tumorigenesis in many cancers, including Merkel cell carcinoma; however, the exact regulatory mechanisms are not fully understood. Survivin is an inhibitor of apoptosis that is undetectable in most terminally differentiated normal human tissues, strongly expressed in embryonic and fetal organs and is strongly expressed in many different human cancers. In this study, we investigated the expression of survivin in cutaneous Merkel cell carcinoma using immunohistochemistry and correlated the findings with long-term clinical follow-up. We collected and immunostained 19 cases of Merkel cell carcinoma with antibodies to survivin. The median patient age was 79 years, with an average follow-up of 17 months, and a male/female ratio of 7:11. All but one sample represented primary lesions and two cases were obtained from one patient. Clinical follow-up was obtained in 15 cases (79%). All 19 cases of Merkel cell carcinoma demonstrated strong immunoreactivity for survivin. Survivin protein was localized and classified into predominately nuclear (N=8) or cytoplasmic (N=4) compartments. A mixed pattern of survivin expression was also seen in three cases. Cases with a nuclear staining pattern were distinguished by an aggressive clinical course, with seven of eight patients developing metastases or dead of disease on follow-up. Furthermore, all of the cases with predominately cytoplasmic survivin localization (N=4) were free of disease on follow-up. Merkel cell carcinomas represent aggressive malignancies regulated by apoptotic pathways. We demonstrate that survivin, a protein with a dual role in inhibition of apoptosis and regulation of cellular proliferation is expressed in Merkel cell carcinoma. Moreover, nuclear subcellular localization of survivin in Merkel cell carcinomas may portend a poor prognosis and identification of these cases may assist clinical management. OBJECTIVE: To investigate the practicability of survivin detection in urine as a novel diagnostic method and prognostic molecular marker of bladder cancer. METHODS: Nested RT-PCR was used to detect survivin mRNA expression in urine specimens from 20 healthy persons and patients with bladder carcinomas (n=30), prostate cancer (n=10), and renal cancer (n=6). RESULTS: The result show that survivin was not detected in the urine samples of six of 30 patients with bladder cancer, whereas all the results were negative the other 36 persons. The positive rates of survivin and their expression levels increased with the tumors' histological grade. Six of 21 new-onset bladder tumors did not present survivin mRNA expression; however, none of the nine recurrent bladder tumors were negative, and patients with new-onset bladder tumors (0.5973+/-0.1968) had significantly lower survivin levels than those with recurrent ones (1.1627+/-0.1341)( P=2.10228E-05). We also found that survivin expression was not correlated with gender, age, and clinical stage. CONCLUSION: The high sensitivity and specificity of urine survivin can indicate the occurrence of bladder carcinomas, and its expression level might be correlated with the malignancy and prognosis of bladder carcinomas. In addition, the fact that survivin was only detected in urine samples of patients with bladder cancer, rather than in normal adult tissue (except thymus gland), suggests that survivin can be used as an ideal target in bladder carcinoma treatment. |
326 | List symptoms of Meigs' Syndrome. | Meigs' syndrome is a benign ovarian tumor associated with ascites and pleural effusion. | [25469326, 23328144, 26046039, 24490014, 24962423] | 433 | BACKGROUND: The Demons-Meigs syndrome should usually be evoked in case of presence of a typical triad: abdominopelvic mass, ascites and hydrothorax. Its diagnosis appears crucial to prevent the realization of unnecessary surgical procedures. CASE PRESENTATION: A 32-year-old woman presented in April 2012 to the emergency department of our maternity unit (General Hospital, Thiers, France) with an abdominal distension mimicking the symptoms of a pregnancy at term. Physical examination revealed a voluminous painful abdominopelvic mass, extended from the pelvis to the upper abdomen with a large right pleural effusion. Ultrasound and computed tomography showed it was a tumor measuring more than 300 mm in diameter with a right hydrothorax. Serum CA-125 level was 289 U/ml. Cytologic analysis of the pleural effusion didn't show any malignant cells. In this study, Demons-Meigs syndrome was recognized. A laparoscopico-laparotomic management permitted an aspiration of 23 liters of a brownish liquid and an unilateral adnexectomy after pleural paracentesis was performed. Frozen section demonstrated benign mucinous cystadenoma. The final histologic findings objectified intracystic intestinal type ovarian mucinous borderline tumor. After multidisciplinary consultation, the patient was re-operated one month later. The exploration didn't reveal any suspected lesions and appendectomy and omentectomy were performed. The postoperative course was uneventful. Serum CA-125 level was normal at the time of the reoperation and 24 months after the initial surgery. CONCLUSION: The preoperative recognition of a Demons-Meigs syndrome or a Demons' pseudosyndrome is essential to avoid useless surgical procedures. BACKGROUND: The Meigs' syndrome is a rare but well-known syndrome defined as the triad of benign solid ovarian tumor, ascites, and pleural effusion. Meigs' syndrome always requires surgical treatment. However, the optimal approach for its management has not been sufficiently investigated. CASE PRESENTATION: We report a patient with a large twisted ovarian fibroma associated with Meigs' syndrome, abdominal pain and severe hemolytic anemia that was treated by laparoscopic surgery. This case highlights the difficulties that may be encountered in the management of patients with Meigs' syndrome, including potential misdiagnosis of the tumor as a malignant ovarian neoplasm that may influence the medical and surgical approach and the adverse impact that Meigs' syndrome can have on the patient's condition, especially if it is associated with acute pain and severe anemia. Considering the patient's serious clinical condition and assuming that she had Meigs' syndrome with a twisted large ovarian mass and possible hemolytic anemia, we first concentrated on effective medical management of our patient and chose the most appropriate surgical treatment after laparoscopic examination. The main aim of our initial approach was preoperative management of the anemia. Blood transfusions and glucocorticoid therapy resulted in stabilization of the hemoglobin level and normalization of the bilirubin levels, which confirmed the appropriateness of this approach. Laparoscopic surgery 4 days after admission enabled definitive diagnosis of the tumor, confirmed torsion and removed the bulky ovarian fibroma, resulting in timely resolution of symptoms, short hospitalization, relatively low morbidity and a rapid return to her social and professional life. CONCLUSIONS: This case highlights the difficulties that may be encountered in the management of patients with Meigs' syndrome, including potential misdiagnosis of the tumor as a malignant ovarian neoplasm that may influence the medical and surgical approach, and the adverse impact that Meigs' syndrome can have on the patient's condition, especially if it is associated with acute pain and severe anemia. The present case suggests that laparoscopic surgery for potentially large malignant tumors is feasible and safe, but requires an appropriate medical and gynecological oncology expertise. |
327 | What is the effect of CRD-BP on the stability of c-myc mRNA? | The c-myc mRNA coding region determinant-binding protein (CRD-BP) has high affinity for the coding region determinant (CRD) of c-myc mRNA. Such affinity is believed to protect c-myc CRD from endonucleolytic attack. | [12894594, 10692488, 10850408, 12024010, 9178888, 16778892, 9801297, 17264115, 11745432] | 434 | The Coding Region Determinant-Binding Protein (CRD-BP) is an RRM and KH-domain-containing protein that recognizes specifically at least three RNAs. It binds to one of the two c-myc mRNA instability elements, to the 5'Un Translated Region (UTR) of the leader 3 IGF-II mRNA and to the oncofetal H19 RNA. CRD-BP has been assigned a role in stabilizing c-myc mRNA by preventing its endonucleolytic cleavage and in repressing the translation of the leader 3 IGF-II mRNA, the major embryonic species of this message. CRD-BP is normally expressed only in fetal tissues. However, its expression is detected in primary tumors and transformed cell lines of different origins. The vast majority of colon (80%) and breast (60%) tumors and sarcomas (73%) express CRD-BP whereas in other tumor types, for example prostate carcinomas, its expression is rare. CRD-BP expression has also been detected in benign tumors such as breast fibroadenomas, meningiomas and other benign mesenchymal tumors, implying a role for this gene in abnormal cell proliferation. In breast carcinomas, CRD-BP expression and or gene copy number gains in the region encompassing the c-myc locus were detected in approximately 75% of tumors, implying that the deregulated expression of c-myc may be more widespread than previously believed. Infiltrated lymph nodes, corresponding to CRD-BP-positive primary tumors, were also found positive indicating that monitoring for CRD-BP could prove useful for the detection and monitoring of disseminated disease. Antisense oligodeoxynucleotides (ODNs) are designed to bind to and inhibit a target mRNA. We used a novel approach for the design of ODNs to the c-myc mRNA using protein binding sites as targets for ODN action. Our strategy was to identify ODNs that could interfere with the coding region determinant-binding protein (CRD-BP), a protein that binds to the CRD region of the c-myc mRNA. Using an in vitro gel shift assay, we show that ODN molecules can occlude the CRD-BP from the mRNA. The best ODN, CRD-ODN4, was able to inhibit RNA binding of the CRD-BP by 75%. This effect was sequence-specific and concentration dependent. K562 cells treated with a 2'-O-methyl derivative of CRD-ODN4 showed a concentration-dependent decrease in both c-myc mRNA and protein levels, with a maximal 65% inhibition of protein expression at 200 nM CRD-ODN4. In contrast, a 2'-O-methyl ODN derivative targeting the translation initiation codon (antimyc-aug) reduced c-myc protein but actually increased mRNA levels, an effect resulting at least partly from stabilization of the c-myc mRNA. CRD-ODN4 treatment did not alter the c-myc mRNA half-life. CRD-ODN4 was more effective in inhibiting K562 cell growth than antimyc-aug, reducing cell number by approximately 70% after 48 h of exposure to 750 nM. The correlation between ODN effects on RNA-protein interactions in vitro and those observed in cells supports the hypothesis that CRD-ODN4 inhibits the interaction between the CRD-BP and the c-myc mRNA and that disrupting this RNA-protein interaction reduces c-myc expression in cells. We previously isolated and characterized a coding region determinant-binding protein (CRD-BP) that might regulate c-myc mRNA post-transcriptionally. CRD-BP binds specifically to the coding region of c-myc mRNA and might stabilize c-myc mRNA in vitro by protecting it from endonucleolytic cleavage. Since c-myc abundance is regulated during embryonic development and cell replication, we investigated whether CRD-BP is also regulated in animal tissues. We focused on CRD-BP expression during rat liver development and liver regeneration, because c-myc mRNA is regulated post-transcriptionally in both cases. CRD-BP expression parallels c-myc expression during liver development; the protein is present in fetal and neonatal liver but is absent or in low abundance in adult liver. In contrast, the up-regulation of c-myc mRNA following partial hepatectomy is not accompanied by up-regulation of CRD-BP. To our knowledge, CRD-BP is the first example of a putative mammalian mRNA-binding protein that is abundant in a fetal tissue but either absent from or scarce in adult tissues. Its expression in fetal liver and in transformed cell lines suggests CRD-BP is an oncofetal protein. Although constitutive activation of beta-catenin/Tcf signalling is implicated in the development of human cancers, the mechanisms by which the beta-catenin/Tcf pathway promotes tumorigenesis are incompletely understood. Messenger RNA turnover has a major function in regulating gene expression and is responsive to developmental and environmental signals. mRNA decay rates are dictated by cis-acting elements within the mRNA and by trans-acting factors, such as RNA-binding proteins (reviewed in refs 2, 3). Here we show that beta-catenin stabilizes the mRNA encoding the F-box protein betaTrCP1, and identify the RNA-binding protein CRD-BP (coding region determinant-binding protein) as a previously unknown target of beta-catenin/Tcf transcription factor. CRD-BP binds to the coding region of betaTrCP1 mRNA. Overexpression of CRD-BP stabilizes betaTrCP1 mRNA and elevates betaTrCP1 levels (both in cells and in vivo), resulting in the activation of the Skp1-Cullin1-F-box protein (SCF)(betaTrCP) E3 ubiquitin ligase and in accelerated turnover of its substrates including IkappaB and beta-catenin. CRD-BP is essential for the induction of both betaTrCP1 and c-Myc by beta-catenin signalling in colorectal cancer cells. High levels of CRD-BP that are found in primary human colorectal tumours exhibiting active beta-catenin/Tcf signalling implicates CRD-BP induction in the upregulation of betaTrCP1, in the activation of dimeric transcription factor NF-kappaB and in the suppression of apoptosis in these cancers. Mouse coding region determinant-binding (mCRD-BP) and human IGF-II mRNA-binding 1 (hIMP-1) proteins are orthologous mRNA-binding proteins that recognize c-myc and IGF-II mRNA, respectively, and regulate their expression posttranscriptionally. Here, we confirm that human CRD-BP/IMP-1 binds to c-myc mRNA and that it is predominantly expressed in fetal tissues. Moreover, hCRD-BP/IMP-1 expression was detected in cell lines of neoplastic origin and in selected primary tumors. In a series of 33 malignant and 10 benign mesenchymal tumors, 73% and 40%, respectively, were found to express hCRD-BP/IMP-1. In particular, expression was significant in 14 Ewing's sarcomas, all of which were positive. The data suggest that hCRD-BP/IMP-1 plays a role in abnormal cell proliferation in mesenchymal tumors. |
328 | What is the molecular function of psoralen photobinding on DNA? | The interaction of two water-soluble furocoumarins, 8-(omega-diethyl aminopropyloxy)psoralen hydrochloride (I) and its 5-isomer (II), with DNA has been investigated by spectroscopic, equilibrium dialysis, hydrodynamic and chiroptical techniques. Both compounds intercalate into the polynucleotide double helix. | [3273186, 1432387, 367436, 10075890, 23416947, 20685815, 1445915, 1821628, 6504703] | 435 | Transcription has the capacity to mechanically modify DNA topology, DNA structure and nucleosome arrangement. Resulting from ongoing transcription, these modifications in turn may provide instant feedback to the transcription machinery. To substantiate the connection between transcription and DNA dynamics, we charted an ENCODE map of transcription-dependent dynamic supercoiling in human Burkitt's lymphoma cells by using psoralen photobinding to probe DNA topology in vivo. Dynamic supercoils spread ~1.5 kilobases upstream of the start sites of active genes. Low- and high-output promoters handled this torsional stress differently, as shown by using inhibitors of transcription and topoisomerases and by chromatin immunoprecipation of RNA polymerase and topoisomerases I and II. Whereas lower outputs are managed adequately by topoisomerase I, high-output promoters additionally require topoisomerase II. The genome-wide coupling between transcription and DNA topology emphasizes the importance of dynamic supercoiling for gene regulation. The effects of different DNA sequences on the photoreaction of various furocoumarin derivatives was investigated from a quantitative point of view using a number of self-complementary oligonucleotides. These contained 5'-TA and 5'-AT residues, having various flanking sequences. The furocoumarins included classical bifunctional derivatives, such as 8-methoxy- and 5-methoxypsoralen, as well as monofunctional compounds, such as angelicin and benzopsoralen. Taking into an account the thermodynamic constant for noncovalent binding of each psoralen to each DNA sequence, the rate constants for the photobinding process to each fragment were evaluated. The extent of photoreaction is greatly affected by the DNA sequence examined. While sequences of the type 5'-(GTAC)n are quite reactive towards all furocoumarins, 5'-TATA exhibited a reduced rate of photobinding using monofunctional psoralens. In addition terminal 5'-TA groups were the least reactive with 5- and 8-methoxypsoralen, but not with angelicin or benzopsoralen. Also 5'-AT-containing fragments exhibited remarkably variable responses toward monofunctional or bifunctional psoralen derivatives. As a general trend the photoreactivity rate of the former is less sequence-sensitive, the ratio between maximum and minimum being less than 2 for the examined fragments. The same ratio is about 3.4 for 8-methoxypsoralen and 6.2 for 5-methoxypsoralen. This approach, in combination with footprinting studies, appears to be quite useful for a quantitative investigation of the process of covalent binding of psoralens to specific sites in DNA. The interaction of two water-soluble furocoumarins, 8-(omega-diethyl aminopropyloxy)psoralen hydrochloride (I) and its 5-isomer (II), with DNA has been investigated by spectroscopic, equilibrium dialysis, hydrodynamic and chiroptical techniques. Both compounds intercalate into the polynucleotide double helix. From the dependence of the binding on ionic strength, ion release and binding free energy corrected for counterion release have been quantitatively estimated. It is shown that the differences in DNA-affinity observed for compounds I and II arise primarily from non electrostatic contributions. The binding process is exothermic, with slightly different van't Hoff enthalpies for the examined furocoumarins. Helix lengthening and dichroic effects indicate different intercalation geometries for the isomeric compounds. These studies allow a possible explanation for the finding that isomer I exhibits largely better DNA-photobinding properties, while isomer II is by far more effective as an antiviral agent. |
329 | Is progesterone effective for treatment of patients with traumatic brain injury based on clinical trial data? | No. Progesterone has been associated with robust positive effects in animal models of traumatic brain injury (TBI) and with clinical benefits in two phase 2 randomized, controlled trials. However, a recent large clinical trial showed no clinical benefit of progesterone in patients with severe TBI. These data stand in contrast to the robust preclinical data and results of early single-center trials that provided the impetus to initiate phase 3 trials. | [22626570, 18522765, 21249708, 19394357, 17418038, 23871679, 24241345, 18447940, 23326789, 24205899, 20486864, 17011666, 23076947, 25493974, 25493978, 22668124, 21497181, 19318112, 19401954, 17588708, 22033509, 22570859, 22300914, 19660659, 17933428, 17327733, 24900479] | 436 | Despite decades of laboratory research and clinical trials, a safe and effective treatment for traumatic brain injury (TBI) has yet to be put into successful clinical use. I suggest that much of the problem can be attributed to a reductionist perspective and attendant research strategy directed to finding or designing drugs that target a single receptor mechanism, gene, or brain locus. This approach fails to address the complexity of TBI, which leads to a cascade of systemic toxic events in the brain and throughout the body that may persist over long periods of time. Attention is now turning to pleiotropic drugs: drugs that act on multiple genomic, proteomic and metabolic pathways to enhance morphological and functional outcomes after brain injury. Of the various agents now in clinical trials, the neurosteroid progesterone (PROG) is gaining attention despite the widespread assumption that it is "just a female hormone" with limited, if any, neuroprotective properties. This perspective should change. PROG is also a powerful developmental hormone that plays a critical role in protecting the fetus during gestation. I argue here that development, neuroprotection and cellular repair have a number of properties in common. I discuss evidence that PROG is pleiotropically neuroprotective and may be a useful therapeutic and neuroprotective agent for central nervous system injury and some neurodegenerative diseases. There are several candidate neuroprotective agents that have been shown in preclinical testing to improve outcomes following traumatic brain injury (TBI). Xiao and colleagues have performed an in hospital, double blind, randomized, controlled clinical trial utilizing progesterone in the treatment of patients sustaining TBI evaluating safety and long term clinical outcomes. These data, combined with the results of the previously published ProTECT trial, show progesterone to be safe and potentially efficacious in the treatment of TBI. Larger phase III trials will be necessary to verify results prior to clinical implementation. Clinical trials networks devoted to the study of TBI are vital to the timely clinical testing of these candidate agents and need to be supported. BACKGROUND: Traumatic brain injury is a leading cause of death and disability. Progesterone is a potential neuroprotective drug to treat patients with traumatic brain injury. OBJECTIVES: To assess the effectiveness and safety of progesterone in people with acute traumatic brain injury (TBI). SEARCH STRATEGY: We searched: the Cochrane Injuries Group's Specialised Register (to April 2010), Cochrane Central Register of Controlled Trials 2010, Issue 1 (The Cochrane Library), MEDLINE (Ovid) (1950 to April week 1 2010), EMBASE (Ovid) (1980 to week 14 2010), LILACS (to 17 April 2010 ), Zetoc (to 21 April 2010), Clinicaltrials.gov (17 April 2010 ), Controlled-trials.com (17 April 2010). SELECTION CRITERIA: We included published and unpublished randomised controlled trials (RCTs) of progesterone versus no progesterone (or placebo) for the treatment of acute TBI. DATA COLLECTION AND ANALYSIS: Two authors independently screened search results to identify the full texts of potentially relevant studies for inclusion. From the results of the screened searches two authors independently selected trials meeting the inclusion criteria, with no disagreement. MAIN RESULTS: Three studies were included with 315 patients. All three studies reported the effects of progesterone on mortality. The pooled relative risk (RR) for mortality at end of follow-up is 0.61, 95% confidence interval (CI) 0.40 to 0.93. Three studies measured disability and found the RR of death or severe disability in patients treated with progesterone was 0.77, 95% confidence interval (CI) 0.62 to 0.96. Two studies presented data on intracranial pressure and adverse events. One study presented blood pressure and temperature data. There was no substantial evidence for the presence of heterogeneity. AUTHORS' CONCLUSIONS: Current clinical evidence from three small RCTs indicates progesterone may improve the neurologic outcome of patients suffering TBI. This evidence is still insufficient and further multicentre randomised controlled trials are required. OBJECTIVE: Severe traumatic brain injury (TBI) has a major role in mortality rate among the other types of trauma. The aim of this clinical study was to assess the effect of progesterone on the improvement of neurologic outcome in patients with acute severe TBI. METHODS: A total of 76 patients who had arrived within 8h of injury with a Glasgow Coma Score≤8 were enrolled in the study. In a randomized style 38 received progesterone (1mg/kg per 12h for 5 days) and 38 did not. RESULTS: There was a better recovery rate and GOS score for the patients who were given progesterone than for those in the control group in a 3-months follow-up period (50% vs. 21%); subgroup analysis showed a significant difference in the percentage of favorable outcome between the two groups with GCS of 5-8 (p=0.03). CONCLUSION: The use of progesterone may significantly improve neurologic outcome of patients suffering severe TBI up to 3 months after injury, especially those with 5≤GCS≤8, providing a potential benefit to the treatment of acute severe TBI patients. Considering this drug had no significant side effects, so progesterone could be used in patients with severe TBI as a neuro-protective drug. OBJECTIVE: To review emerging pharmacological agents for the treatment of traumatic brain injury with regard to survival outcomes and provide recommendations regarding their use. METHODS: An Ovid MEDLINE (up to May 2013) and the Cochrane Central Register of Controlled Trials (up to May 2013) search was conducted to identify emerging pharmacological therapies for the treatment of traumatic brain injury. The search was limited to English language and humans. Pharmacological agents that were evaluated with respect to survival as an outcome were included. MAIN RESULTS: Based on the search, the investigators identified the following new therapies: beta-receptor antagonists, erythropoiesis stimulating agents, hydroxymethylglutaryl-CoA reductase inhibitors (statins) and progesterone. With the exception of progesterone, which was studied in several small, randomized, controlled trials, the remaining agents were primarily studied in observational retrospective cohorts. For each of the agents identified, a potential increase in survival was noted. CONCLUSIONS: Emerging pharmacological agents represent promising treatment options for traumatic brain injury to improve survival. Most of these agents are commercially available for other indications. However, limitations in study design, sample size, duration of treatment, timing of treatment and inclusion of heterogeneous patient populations make it difficult to draw definitive conclusions from the literature. IMPORTANCE OF THE FIELD: Traumatic brain injury (TBI) has yet to find a safe and effective acute-stage neuroprotective treatment. Experimental drugs targeting a single receptor mechanism, gene, or brain locus have failed. AREAS COVERED IN THIS REVIEW: We review the latest clinical trials using progesterone (PROG) to treat moderate to severe TBI, and present background showing why this hormone and some of its metabolites should be considered as candidates for neuroprotective therapy. TBI is a complex disease caused by a cascade of systemic toxic events in the brain and throughout the body. Attention is now turning to combinatorial or pleiotropic drugs that act on multiple genomic, proteomic and metabolic pathways to enhance morphological and functional outcomes. WHAT THE READER WILL GAIN: PROG has long been considered merely a female reproductive hormone with little role in neuroprotection after brain injury. This review will help readers to understand that PROG and its metabolites have multiple neuroprotective mechanisms, and may be among the first safe, low-cost, easily administered, effective treatments for a variety of CNS disorders. TAKE HOME MESSAGE: The idea that PROG is just a female reproductive hormone is outdated. We propose that PROG has substantial pleiotropic properties as a neuroprotective agent in a variety of CNS injury models. BACKGROUND: Traumatic brain injury (TBI) is a leading cause of death and disability. Progesterone is a potential neuroprotective drug to treat patients with TBI. OBJECTIVES: To assess the effectiveness and safety of progesterone in people with acute TBI. SEARCH METHODS: We searched: the Cochrane Injuries Group's Specialised Register (13 July 2012), Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 7, 2012), MEDLINE (Ovid) (1950 to August week 1, 2012), EMBASE (Ovid) (1980 to week 32 2012), LILACS (12 August 2012), Zetoc (13 July 2012), Clinicaltrials.gov (12 August 2012), Controlled-trials.com (12 August 2012). SELECTION CRITERIA: We included published and unpublished randomised controlled trials (RCTs) of progesterone versus no progesterone (or placebo) for the treatment of people with acute TBI. DATA COLLECTION AND ANALYSIS: Two review authors independently screened search results to identify the full texts of potentially relevant studies for inclusion. From the results of the screened searches two review authors independently selected trials meeting the inclusion criteria, with no disagreement. MAIN RESULTS: Three studies were included with a total of 315 people. Two included studies were of high methodological quality, with low risk of bias in allocation concealment, blinding and incomplete outcome data. One study did not use blinding and had unclear risk of bias in allocation concealment and incomplete outcome data. All three studies reported the effects of progesterone on mortality. The pooled risk ratio (RR) for mortality at end of follow-up was 0.61, 95% confidence interval (CI) 0.40 to 0.93. Three studies measured disability and found the RR of death or severe disability in patients treated with progesterone to be 0.77, 95% CI 0.62 to 0.96. Data from two studies showed no difference in mean intracranial pressure or the rate of adverse and serious adverse events among people in either group. One study presented blood pressure and temperature data, and there were no differences between the people in the progesterone or control groups. There was no substantial evidence for the presence of heterogeneity. AUTHORS' CONCLUSIONS: Current clinical evidence from three small RCTs indicates progesterone may improve the neurologic outcome of patients suffering TBI. This evidence is still insufficient and further multicentre randomised controlled trials are required. Collaborators: Wright DW, Frankel M, Merck LH, Espinoza TR, Salomone JP, Dhall SS, Hudgins PA, Allen JW, Goldstein F, Hertzberg V, Rogers SD, Calcaterra AM, Howlett-Smith H, Lane B, Lunney MP, Cook N, Hall A, Hall A, McDougal A, Subramanian A, Pradilla G, Stein DG, Silbergleit R, Barsan WG, Pancioli A, Lowenstein D, Meurer WJ, Morgenstern LB, Stevenson V, Bengelink E, Harney D, De Yampert A, Mawocha S, Pinkerton J, Caveney A, Yeatts S, Palesch Y, Zhao W, Pauls Q, Pauls K, Dillon CR, Conner C, Henry A, Patel K, Simons JL, Manley G, Aarabi B, Harris O, Hemphill C, LeRoux P, Narayan R, Okonkwo DO, Pascual J, Salomone JP, Schwab W, Valadka A, Wright DW, Janis S, Conwit R, Denninghoff K, Friese R, Zabramski J, Oneill PJ, Feinstein A, Yonas H, Stasinski G, Barnhart B, Wood L, Haney S, Livergood DL, Burlbaw B, Wright DW, Frankel M, Croce MA, McCafferty RR, Lunney MP, Panzer-Baggett S, Warren JB, Hall AJ, McDougal AG, Cook N, Wilson S, Waddle-Smith L, Barrow S, Pitotti R, Espinoza TR, Hudgins PA, Allen JW, Subramanian A, Fabian TC, Muhlbauer MS, Hilliard MW, Bebarta VS, Gunst MA, Amador RR, Lo IW, Quinn JV, Lee M, Blumenfeld K, Venkatasubramanian C, Visweswaran A, Mann R, Harris OA, D'Souza P, Spain DA, Hirsch K, Torres R, Kline R, Benford J, Traver C, Yeh D, Pancioli A, Shutter L, Johannigman J, Bonomo J, Stark S, Ewing I, Waymeyer P, Schmit P, Adeoye O, Mcmullan J, Robinson B, Andaluz N, Newman P, Biros M, Irwin ED, Dries DJ, Rockswold G, Miller K, Sargent C, Reicks P, Wewerka SS, Salzman J, Zagar A, Kragness K, Hildebrandt D, Scherber J, Bennett BA, Zwank MD, Jones E, Milling TJ Jr, Ottman M, Mendoza-Moore M, LaChance L, King B, Doshi P, Aufderheide TP, Lynch J, Torbey M, Boettcher M, Bialkowski W, Brandt JT Jr, Burpee K, Gauger S, Herdeman C, Hermanson B, Hessenthaler A, Jasti J, McCormick K, Mena M, Morrow K, Price G, Sandoval C, Qaisar T, Quering B, Zellner S, Zeisse M, Brasel K, Maiman D, Zaidat OO, Baren JM, Portner M, Merck LH, Sarani B, Stehly C, Bertsch K, Garey C, Lamond K, Durinka JB, Gromek S, Jochym N, Pascual JL, Kasner SE, LeRoux PD, Schuster J, Gentile NT, Saks M, Fisher MA, Jallo J, Timmons S, McNelis PM, Reimer H, Nocera R, Campbell NA, Gardner K, Weaver M, Goldberg A, Wang A, Healy M, Warden CR, Prewitt L, Hilliard C, Schreiber M, Lowe R, Ornato JP, Mathern BE, Mathern K, Merchant RE, Feeser VR, Dhindsa HS, Leahman CE, Humphries RL, Short J, Dechtenberg L, Taylor DG, Pettigrew L, Carter CT, Desai S, Welch RD, Swor RA, Mika VH, Paternoster RA, Norris GM, Coplin WM, Pearson C, O'Neil BJ, Ayaz SI, Clark CL, Sawyer KN, Rae RW Jr, Wiener MA, Grace HA, Hemphill J 3rd, Meeker M, Duncan J, Alvarado E, Casey S, Lauder I, Manley G, Lewandowski CA, Miller JB, Borgialli DA, Lundell AM, Baker A, LaChance J, Falvo A, Abdelhak T, Vohra T, Nagarwala J, Fowkes R, Claassen J, Rosengart A, Falo M, Fokken T, Agarwal S, Lord A, Connolly E, Velander A, Pavol M, Zammit C, Foreman B, Mayer S, Stern B, Eisenberg H, Aldrich C, Ganley V, Aarabi B, Goldstein JN, Rosenthal ES, Burke P, Nentwich LM, Howell M, Mitchell P, Riklin E, Feldman J, Levine SR, Jain A, Zelonis S, Bushey M, Sinert R, Ver Halen N, Rojas-Soto D, Martindale J, Paladino L, Legome E, Valsamis LH, Brandler E, Chatterjee P, Torbey M, Green A, Angelos M, Caterino J, Elder J, Steinberg S, Callaway C, Okonkwo DO, Puccio AM, Shutter LA, Dezfulian C. Collaborators: Marmarou A, Maas AI, Narayan R, Skolnick BE, Ward J, Stocchetti N, Dearden NM, Clarence-Smith K, Genazzani AR, Grady MS, Steyerberg EW, Okonkwo D, Grieve G, Zaaroor M, Levi L, Smrcka M, May A, Pachl J, Manji M, Chen J, Pichon N, Lobato RD, Norasetthada T, Puybasset L, Petit L, Meisel H, Fakhry S, Wilberger J, Sahuquillo J, Rabb C, Walsh J, Mokry M, Yutthakasemsunt S, Huynh T, Rumana C, Audibert G, Citerio G, Agazzi S, Gruen J, O'Leary S, Ransom K, Trimmel H, Turner M, Zucker L, Umansky F, Nardi G, Dominguez JI, Zauberman J, Claridge J, Bulters D, Mace JC, McCarthy M, Colpaert K, Ratanalert S, Couture D, Choi K, Verma V, Cheng Y, Wang E, Rosen C, Medow J, Patterson L, Alberico A, Avila RA, Vega E, Unterberg A, Stocchetti N, Zhou L, Wong S, Beretta L, Laskowitz D, Vincent JL, Dominguez-Roldán J, Molina JM, Wang Z, Coimbra R, German J, Emhoff T, Boakye M, Surdell DL, García E, Leone M, Nimsky C, Sandesc D, Nagy L, Badenes R, Öhman J, Barnes S, Jacoby M, Shillinglaw W, Orlandi C, Vander Laenen M, Grigoriev R, Rohde V, Vajkoczy P, Raventós AA, Minguillón MA, Oram J, Kuang Y, Chou N, Grindlinger G, Rodgers R, Tinti M, Nagy K, Pellegrini J, George R, Brevard SB, Barbozà A, Payen JF, Troubleyn J, Lavicka P, van der Naalt J, Spoelstra-de Man A, Molina JA, Miranda P, Lopez PM, Wright J, Thambinayagam H, Cheng W, Fulda G, Garrote M, Schmutzhard E, Depreitere B, Greiner C, Zacharowski K, Nevo M, Kang D, Yu R, Alias A, Nor MM, Espinosa J, Shaffrey M, Beauchamp K, Faber T, Dailler F, Cejpek P, Belkin S, Sardaryan I, Kobyakov G, Orel V, Weber F, Procaccio F, Della Corte F, Barzó P, Laha S, Zhang B, Cheang V, Arnold P, Badr A, Andersen B, Putnam A 2nd, Murali R, Videtta W, Regelsberger J, Rappaport ZH, Büki A, Mendiluce RM, Kumar D, Ng I, Tu YK. Despite decades of laboratory research and clinical trials, a safe and effective treatment for traumatic brain injury has yet to reach clinical practice. The failure is due in part to the prevalence of a reductionist philosophy and research praxis that targets a single receptor mechanism, gene, or brain locus. This approach fails to account for the fact that traumatic brain injury is a very complex disease caused by a cascade of systemic toxic events in the brain and throughout the body. Attention is now turning to pleiotropic drugs that act on multiple genomic, proteomic, and metabolic pathways to enhance morphological and functional outcomes after brain injury. Of the agents now in clinical trial, the neurosteroid progesterone appears to hold considerable promise. Many still assume that progesterone is "just a female hormone" with limited, if any, neuroprotective properties, but this view is outdated. This review will survey the evidence that progesterone has salient pleiotropic properties as a neuroprotective agent in a variety of central nervous system injury models. This article is part of a Special Issue entitled: Neuroactive Steroids: Focus on Human Brain. Studies on the neuroprotective and promyelinating effects of progesterone in the nervous system are of great interest due to their potential clinical connotations. In peripheral neuropathies, progesterone and reduced derivatives promote remyelination, axonal regeneration and the recovery of function. In traumatic brain injury (TBI), progesterone has the ability to reduce edema and inflammatory cytokines, prevent neuronal loss and improve functional outcomes. Clinical trials have shown that short-and long-term progesterone treatment induces a significant improvement in the level of disability among patients with brain injury. In experimental spinal cord injury (SCI), molecular markers of functional motoneurons become impaired, including brain-derived neurotrophic factor (BDNF) mRNA, Na,K-ATPase mRNA, microtubule-associated protein 2 and choline acetyltransferase (ChAT). SCI also produces motoneuron chromatolysis. Progesterone treatment restores the expression of these molecules while chromatolysis subsided. SCI also causes oligodendrocyte loss and demyelination. In this case, a short progesterone treatment enhances proliferation and differentiation of oligodendrocyte progenitors into mature myelin-producing cells, whereas prolonged treatment increases a transcription factor (Olig1) needed to repair injury-induced demyelination. Progesterone neuroprotection has also been shown in motoneuron neurodegeneration. In Wobbler mice spinal cord, progesterone reverses the impaired expression of BDNF, ChAT and Na,K-ATPase, prevents vacuolar motoneuron degeneration and the development of mitochondrial abnormalities, while functionally increases muscle strength and the survival of Wobbler mice. Multiple mechanisms contribute to these progesterone effects, and the role played by classical nuclear receptors, extra nuclear receptors, membrane receptors, and the reduced metabolites of progesterone in neuroprotection and myelin formation remain an exciting field worth of exploration. Biologic sex and sex steroids are important factors in clinical and experimental stroke and traumatic brain injury (TBI). Laboratory data strongly show that progesterone treatment after TBI reduces edema, improves outcomes, and restores blood-brain barrier function. Clinical studies to date agree with these data, and there are ongoing human trials for progesterone treatment after TBI. Estrogen has accumulated an impressive reputation as a neuroprotectant when evaluated at physiologically relevant doses in laboratory studies of stroke, but translation to patients remains to be shown. The role of androgens in male stroke or TBI is understudied and important to pursue given the epidemiology of stroke and trauma in men. To date, male sex steroids remain largely evaluated at the bench rather than the bedside. This review evaluates key evidence and highlights the importance of the platform on which brain injury occurs (i.e., genetic sex and hormonal modulators). In this article, we review published preclinical and epidemiologic studies that examine progesterone's role in the central nervous system. Its effects on the reproductive and endocrine systems are well known, but a large and growing body of evidence, including a recently published pilot clinical trial, indicates that the hormone also exerts neuroprotective effects on the central nervous system. We now know that it is produced in the brain, for the brain, by neurons and glial cells in the central and peripheral nervous system of both male and female individuals. Laboratories around the world have reported that administering relatively large doses of progesterone during the first few hours to days after injury significantly limits central nervous system damage, reduces loss of neural tissue, and improves functional recovery. Although the research published to date has focused primarily on progesterone's effects on blunt traumatic brain injury, there is evidence that the hormone affords protection from several forms of acute central nervous system injury, including penetrating brain trauma, stroke, anoxic brain injury, and spinal cord injury. Progesterone appears to exert its protective effects by protecting or rebuilding the blood-brain barrier, decreasing development of cerebral edema, down-regulating the inflammatory cascade, and limiting cellular necrosis and apoptosis. All are plausible mechanisms of neuroprotection. La progestérone est indispensable à la grossesse normale mais nous savons maintenant qu'elle a aussi d'autres fonctions importantes. De récentes recherches démontrent que cette hormone est aussi un puissant neurostéroïde susceptible de protéger les cellules des systèmes nerveux périphérique et central altérées, et qu'elle est capable d'action rapide allant bien au-delà de ses effets sur le classique récepteur intranucléaire à la progestérone. Des années de recherche préclinique ont démontré sa sécurité d'emploi et son efficacité dans des modèles animaux de lésion du système nerveux central. L'hormone a été récemment évaluée dans deux études cliniques de phase 2 pour les lésions cérébrales traumatiques (LCT). Une étude clinique nationale de phase 3, financée par les National Institutes of Health aux États-Unis, évalue maintenant la progestérone dans les LCT modérées à sévères chez 1 200 patients. Une étude internationale de phase 3 financée par l'industrie est également en cours ainsi que la planification d'une étude utilisant la progestérone pour traiter les lésions cérébrales chez l'enfant. Des données précliniques suggèrent que la progestérone pourrait être aussi efficace dans les accidents vasculaires cérébraux et certains troubles neurodégénératifs. Progesterone (PROG) has been shown to protect the brain from traumatic injury and is now in Phase III clinical trials. Our work shows that PROG's beneficial effects can be reduced in vitamin D hormone (VDH)-deficient subjects. VDH can modulate neuronal apoptosis, trophic factors, inflammation, oxidative stress, excitotoxicity, and myelin and axon repair. We investigated whether VDH combined with PROG could improve behavioral outcomes more than PROG alone in VDH-sufficient rats given bilateral contusions of the medial frontal cortex. PROG and different doses of VDH (1 μg/kg, VDH1; 2.5 μg/kg, VDH2; 5 μg/kg, VDH3) were injected intraperitoneally 1 h post-injury. Eight additional doses of PROG were given subcutaneously over 8 days with tapering over the last 2 days. Neurobehavioral tests, necrotic cavity, neuronal death and activation of astrocytes were evaluated 21 days post-injury. We found that PROG and PROG + VDH preserve spatial memory processing. VDH1 + PROG improved performance in acquisition more effectively than PROG alone, indicating that the low VDH dose is optimal for combination therapy. There were no significant differences in necrotic cavity size among the groups. The density of positive staining for reactive astrocytes (glial fibrillary acidic protein (GFAP)) increased and the cell bodies and processes of GFAP-positive cells were enlarged in the PROG + VDH1 group. Our data indicate that the combination of PROG and VDH is more effective than PROG alone in preserving spatial and reference memory, and that PROG plus low-dose VDH can activateGFAP reactions up to 21 days after injury. This effect may be one of the mechanisms underlying PROG's neuroprotective effects in combination with VDH. OBJECTIVE: To evaluate all the possible therapeutic measures concerning the acute management of traumatic brain injury (TBI) mentioned in Cochrane Systematic Reviews published in the Cochrane Database of Systematic Reviews (CDSR). METHODS: An exhausted literature search for all published Cochrane Systematic Reviews discussing therapeutic rather than prevention or rehabilitative interventions of TBI was conducted. We retrieved such databases as CDSR and Cochrane Injury Group, excluded the duplications, and eventually obtained 20 results, which stand for critical appraisal for as many as 20 different measures for TBI patients. The important data of each systematic review, including total population, intervention, outcome, etc, were collected and presented in a designed table. Besides, we also tried to find out the possible weakness of these clinical trials included in each review. RESULTS: Analysis of these reviews yielded meanfuling observations: (1) The effectiveness of most ordinary treatments in TBI is inconclusive except that corticosteroids are likely to be ineffective or harmful, and tranexamic acid, nimodipine and progesterone show a promising effect in bleeding trauma, traumatic subarachnoid hemorrhage, TBI or severe TBI. (2) A majority of the systematic reviews include a small number of clinical trials and the modest numbers of patients, largely due to the uncertainty of the effectiveness. (3) The quality of most trials reported in the systematic reviews is more or less questionable. (4) In addition, lots of other complex factors together may lead to the inconclusive results demonstrated in the Cochrane Systematic Reviews. CONCLUSIONS: For clinical physicians, to translate these conclusions into practice with caution is essential. Basic medication and nursing care deserve additional attention as well and can be beneficial. For researchers, high quality trials with perfect design and comprehensive consideration of various factors are urgently required. PURPOSE OF REVIEW: Translating the efficacy of neuroprotective agents in experimental traumatic brain injury to clinical benefit has proven an extremely complex and, to date, unsuccessful undertaking. The focus of this review is on neuroprotective agents that have recently been evaluated in clinical trials and are currently under clinical evaluation, as well as on those that appear promising and are likely to undergo clinical evaluation in the near future. RECENT FINDINGS: Excitatory neurotransmitter blockage and magnesium have recently been evaluated in phase III clinical trials, but showed no neuroprotective efficacy. Cyclosporin A, erythropoietin, progesterone and bradykinin antagonists are currently under clinical investigation, and appear promising. SUMMARY: Traumatic brain injury is a complex disease, and development of clinically effective neuroprotective agents is a difficult task. Experimental traumatic brain injury has provided numerous promising compounds, but to date these have not been translated into successful clinical trials. Continued research efforts are required to identify and test new neuroprotective agents, to develop a better understanding of the sequential activity of pathophysiologic mechanisms, and to improve the design and analysis of clinical trials, thereby optimizing chances for showing benefit in future clinical trials. |
330 | Is there a role for the cylindromatosis tumor suppressor (CYLD) in lung cancer? | To explore a correlation between CYLD expression and responsiveness to TRAIL in lung cancer cell lines, we established lung cancer cell lines that stably express CYLD. Our data provided the first evidence that increased expression of CYLD directly blocks TRAIL-induced NF - B activation, and consequently increases TRAIL-induced apoptosis in lung cancer cells. CYLD may act as a therapeutic target of lung cancer. Targeting CYLD, in combination with TRAIL, may be a new strategy to treat lung cancer with high NF - B activity. Cyld encodes a 956-amino acid deubiquitinating enzyme, which is a negative regulator of nuclear factor kappaB and mitogen-activated protein kinase pathways. Mutations that truncate and inactivate the carboxyl-terminal deubiquitinating domain of CYLD underlie the development of skin appendage tumors in humans, whereas down-regulation of Cyld expression has been associated with the development of various types of human malignancies including lung cancer. To establish an animal model of human CYLD inactivation and characterize the biological role of CYLD in vivo, we generated mice carrying a homozygous deletion of Cyld exon 9 mice ) using a conditional approach. Our study identifies an important role of CYLD in lung maturation, which may underlie the development of many cases of lung cancer. | [22017589, 19412431] | 437 | Cyld encodes a 956-amino acid deubiquitinating enzyme (CYLD), which is a negative regulator of nuclear factor kappaB and mitogen-activated protein kinase pathways. Mutations that truncate and inactivate the carboxyl-terminal deubiquitinating domain of CYLD underlie the development of skin appendage tumors in humans, whereas down-regulation of Cyld expression has been associated with the development of various types of human malignancies including lung cancer. To establish an animal model of human CYLD inactivation and characterize the biological role of CYLD in vivo, we generated mice carrying a homozygous deletion of Cyld exon 9 (Cyld(Delta 9/Delta 9) mice) using a conditional approach. Deletion of exon 9 would cause a carboxyl-terminal truncation of CYLD and inactivation of its deubiquitinating activity. In accordance with previous studies, fibroblasts from Cyld(Delta 9/Delta 9) embryos had hyperactive nuclear factor kappaB and c-Jun kinase pathways compared with control fibroblasts. Cyld(Delta 9/Delta 9) newborn mice were smaller than wild-type littermates with a short and kinky tail and no major developmental defects. However, Cyld(Delta 9/Delta 9) mice died shortly after birth from apparent respiratory dysfunction. Histological examination of E18.5 Cyld(Delta 9/Delta 9) lungs demonstrated an immature phenotype characterized by hyperplasic mesenchyme but apparently normal epithelial, smooth muscle. and endothelial structures. Our study identifies an important role of CYLD in lung maturation, which may underlie the development of many cases of lung cancer. |
331 | Which medical diagnostic tests are used to test kidney function? | Most common tests used in diagnosing normal kidney function include blood tests such as serum creatinine levels, glomerular filtration rate (GFR) and blood urea nitrogen (BUN) levels, also medical imaging tests like ultrasound and CT Scan. Additionally kidney biopsy is used in more direct but invasive approach. Lastly, and probably the most relevant tests to kidney function are urine tests along the lines of urinalysis, urine protein levels and microalbuminuria creatinine clearance. | [23097569, 23449218, 22973348, 23106053, 23952327, 23521456, 2510609, 23526674, 23194995, 23650931, 22257305, 20978142, 22797727] | 438 | To estimate the glomerular filtration rate (GFR) in conscious rabbits, a single-sample method using the non-ionic contrast medium iodixanol was compared with a three-sample method using the standard agent inulin. Iodixanol and inulin were co-administered intravenously to male New Zealand White rabbits at 60 mg I/kg and 40 mg/kg, respectively, and blood was collected 30, 60, 90 and 120 min later. Serum iodixanol and inulin concentrations were separately determined by high performance liquid chromatography and colorimetry, respectively. Serum urea nitrogen (UN) and creatinine concentrations were also determined. Based on the data from healthy and cisplatin-treated rabbits, the GFR estimated by iodixanol was well consistent with that by inulin. Further, when the GFR decreased to more than 60% of the reference value, serum creatinine concentrations became elevated. However, serum UN concentrations exhibited wide fluctuations, presumably due to a difference in renal handlings. The single-sample method using iodixanol was considered to be an expedient tool in both clinical and research settings, because the stress due to a multi-sample method was reduced. BACKGROUND: Increased proteinuria would lead to a larger risk for renal failure in the long term. Therefore, proteinuria requires immediate and thorough evaluation. This study was designed to evaluate the effects of pioglitazone on proteinuria in patients with non-diabetic renal disease. METHODS: In this self-controlled clinical trial study, forty four non-diabetic patients aged 18 and more, who had renal disease and a stable proteinuria of over 0.5 g in 24 hour, were studied. All patients received 15 mg of daily pioglitazone for 4 months. Urine protein excretion was measured as a main end point prior to the study, at the end of the 2nd and 4th months of treatment, and 2 and 4 months after the cessation of the active drug. Other evaluated variables included systolic blood pressure, serum creatinine, urea, alanine aminotransferase (ALT), aspartate aminotransferase (AST), fasting blood sugar (FBS), blood urea nitrogen (BUN) and glomerular filtration rate (GFR) levels. RESULTS: Proteinuria (mean ± SEM) prior to the study, at the 2nd and 4th months of the treatment, and 2 and 4 months after the cessation of pioglitazone were 1088.6 ± 131.1, 699.9 ± 118.3, 433.9 ± 68.7, 416.1 ± 54.9 and 646.9 ± 89.1, respectively (p < 0.001). In addition, the reduction of 24-hour urine protein was statistically significant for both male and female patients (p < 0.001 for both). CONCLUSIONS: A reduction of proteinuria in patients with non-diabetic renal disease was observed during the 4-month treatment with pioglitazone which continued for 2 months after the cessation of the treatment. However, 4 months after the cessation of the treatment, a little increase was detected in the level of proteinuria. The aim of this study was to investigate the normal values of glomerular filtration rate (GFR) by technetium-99m diaethylene-triamine-pentaacetic acid ((99m)Tc-DTPA) renal dynamic imaging for living kidney graft donors. In a total of 212 candidate donors, GFR was examined using (99m)Tc-DTPA renal dynamic imaging. Donors with GFR≥80mL/(min×1.73m(2)) and as low as with GFR≥70mL/(min×1.73m(2)) but a normal endogenous creatinine clearance rate (CCr) were quantified for living kidney donation. Differences in GFR levels based on sex and age were analyzed using rank correlation coefficient. Out of the 212 candidates, 161 were finally selected as kidney graft donors. The double kidney total GFR between the male and female donor groups, the GFR levels among differently-aged donor groups, and the GFR levels between the elderly (>55 years) and young- and middle-aged (≤55 years) donor groups did not show any significant difference (P>0.05). After kidney donation, renal function measured by blood urea nitrogen (BUN) and serum creatinine of all donors returned to normal within one week, and no serious complications were noticed. In conclusion, renal dynamic imaging by (99m)Tc-DTPA had a good accuracy and repeatability in GFR evaluation for living kidney donors. Candidate donors with GFR between 70mL/(min×1.73m(2)) and 80mL/(min×1.73m(2)) can be selected as kidney donors after strict screening. In living kidney donors GFR is not significantly correlated with age or sex. OBJECTIVE: The objective of this article is to review and evaluate the various parameters used in determining renal status. CONCLUSION: The physiologic determination of renal status is the measured glomerular filtration rate (mGFR). Serum creatinine, blood urea nitrogen, cystatin C, and estimated GFR (eGFR), based on serum creatinine have failed to replace mGFR. All physicians should be aware of limitations of substituted mGFR. Eighty measurements of plasma creatinine concentration, height:creatinine ratio, and plasma beta 2 microglobulin concentration were made on 72 children (age 4 months-18.5 years) with known renal disease. Results were compared with simultaneous measurements of glomerular filtration rate using plasma clearance of 51Cr edetic acid to assess the performance of each test as an initial screening procedure of renal insufficiency. Height:creatinine index less than 2.1 was found to have a higher sensitivity and predictive value of a normal result than the other tests and is therefore the preferred test for a screening procedure. STUDY OBJECTIVE: To determine the rate, risk factors, and outcome of vancomycin-associated acute kidney injury (AKI) in critically ill children. DESIGN: Retrospective cohort study. SETTING: Tertiary care children's hospital. PATIENTS: We reviewed the charts of children admitted to the pediatric intensive care unit during a 2-year period who were treated with vancomycin. Courses of vancomycin interrupted by 3 days or more were counted separately. Patients were excluded if they received vancomycin treatment for fewer than 3 days, had preexisting renal failure, or had incomplete serum creatinine (Scr ) data. MEASUREMENTS AND MAIN RESULTS: Demographic and laboratory data; vancomycin dose, duration, and concentrations; and concurrent use of nephrotoxic drugs were recorded. Acute kidney injury was defined as a decrease in estimated glomerular filtration rate of 50% or more from the beginning of vancomycin therapy. Descriptive statistics, step-wise logistic regression, and repeated measures ANOVA were used to analyze the data. A total of 284 patients were included, for a total of 391 courses of vancomycin (272 children and 119 infants). The mean duration of vancomycin therapy was 6.9 ± 4.5 days. Forty nine (17.2%) patients developed AKI during 61 (15.6%) courses. Elevated Scr concentrations returned to baseline after stopping vancomycin in 53 (87%) courses. Mortality was higher in children who developed AKI (p<0.001; Fisher's exact test). Administration of nephrotoxic drugs (odds ratio 2.23, Confidence Interval 1.27-3.93) and presence of high blood urea nitrogen (BUN):Scr ratio before vancomycin therapy (p<0.05) were associated with AKI. The BUN and Scr concentrations significantly increased during vancomycin therapy and decreased after vancomycin was discontinued (p<0.05). CONCLUSIONS: In critically ill children, the development of reversible AKI during vancomycin therapy is associated with administration of nephrotoxic drugs and an elevated BUN: Scr ratio. BACKGROUND: Decreased tryptophan (TRP) and increased kynurenine (KYN) and kynurenic acid (KYNA) in blood have been reported in patients and experimental animals with renal diseases. We investigated if these compounds could be used as new biomarkers for the assessment of renal function. METHODS: Eighty hospitalized hypertensive patients (20 with chronic kidney disease (CKD), and other 60 were considered as control) were enrolled for the investigation. Plasma TRP, KYN, and KYNA were determined by high-performance liquid chromatography. Change rate (CR) was employed to evaluate the sensitivity of the parameters of renal function. RESULTS: CR of plasma KYNA/TRP ratio (+103%) was much higher than the CRs of blood urea nitrogen (+44%), serum creatinine (+56%) and estimated glomerular filtration rate (-35%). Plasma KYNA/TRP ratio was in close relationship with blood urea nitrogen (r = 0.622), serum creatinine (r = 0.797), urine micro-albumin/24-h (r = 0.518) and estimated glomerular filtration rate (r = -0.662), respectively, with all p-values <0.001. CONCLUSIONS: Plasma KYNA/TRP ratio was sensitive and reliable to indicate renal function and could be used as a new biomarker to assess the risk or presence of kidney disease. There is much symptomatic similarity between acute kidney disease and acute heart disease. Both may present with shortness of breath and chest discomfort, and thus it is not surprising that biomarkers of acute myocardial and renal disease often coexist in many physicians' diagnostic work-up schedules. In this review we explore the similarities and differences between current and future tests of myocardial and renal injury and function, with particular emphasis on the diagnostic utility of currently available biomarkers to assist with the diagnosis of cardiorenal syndromes. Imaging studies have not traditionally been viewed as clinical biomarkers, but as tests of structure and function; they contribute to the diagnostic process, and we believe that they should be considered alongside more traditional biomarkers such as blood and urine measurements of circulating proteins and metabolites. We discuss the place of natriuretic peptides, novel tests of kidney damage as well as kidney function and conclude with a discussion of their place in guiding future research studies whose goals must include better characterization of the degree of dysfunction imposed on one organ system by failure of the other. |
332 | Against which protein is the antibody used for immonostaining of Lewy bodies raised? | alpha-Synuclein is a presynaptic protein, which was identified as a specific component of Lewy bodies (LB) and Lewy neurites. Therefore, immunostaining for detecting the presence of Lewy bodies is carried out using antibodies against alpha-synuclein. | [9600226, 12536227, 19272424, 9759660, 10967182, 16691119, 11005264, 12722831, 15854770, 10867800, 22370907, 10822429, 11207422, 10787032] | 439 | A mutation in the alpha-synuclein gene has recently been linked to some cases of familial Parkinson's disease (PD). We characterized the expression of this presynaptic protein in the midbrain, striatum, and temporal cortex of control, PD, and dementia with Lewy bodies (DLB) brain. Control brain showed punctate pericellular immunostaining. PD brain demonstrated alpha-synuclein immunoreactivity in nigral Lewy bodies, pale bodies and abnormal neurites. Rare neuronal soma in PD brain were immunoreactive for alpha-synuclein. DLB cases demonstrated these findings as well as alpha-synuclein immunoreactivity in cortical Lewy bodies and CA2-3 neurites. These results suggest that, even in sporadic cases, there is an early and direct role for alpha-synuclein in the pathogenesis of PD and the neuropathologically related disorder DLB. Diffuse Lewy body disease (DLBD) is characterized by the presence of Lewy bodies (LB) in the neurons and neurites of cortical, subcortical, and brain stem structures. Recently, alpha-synuclein (alphaS) has been found to be a central constituent of LB. In DLBD, abnormal accumulation of alphaS has been reported in both neurons and glia, but studies on glial lesions in DLBD have been limited. We examined in detail the constituents and distribution of glial lesions in eight patients with DLBD and report the pathogenesis of the glial lesions. alphaS-positive neuronal cytoplasmic inclusions (NI), neuropil threads (NT), and coiled bodies (CB) showed similar immunostaining profiles. Without pretreatment, NI, NT, and CB were detected by all antibodies against alphaS. The immunostaining profile of star-like astrocytes (SLA) was quite different from those of NI, NT, and CB. A few SLA were stained by an antibody against the non-Abeta component portion of alphaS without pretreatment, but formic acid pretreatment dramatically enhanced SLA immunoreactivity. SLA and CB were found in all eight brains with DLBD. SLA were scarce in the brain stem, but there were hundreds of SLA per visual field at x100 magnification in the temporal cortex of most cases, while CB were found diffusely in both the cerebral cortex and brain stem, similar to NI. This suggests that the pathogenesis of SLA is different from those of NI and CB. Parkinson's disease and dementia with Lewy bodies are very frequent neurological disorders of the elderly. Mutations in the alpha-synuclein (alphaSYN) gene cause Parkinson's disease, often associated with dementia. Neuropathologically these diseases are characterized by the presence of Lewy bodies and Lewy neurites, intraneuronal inclusions mostly composed of alphaSYN protein fibrils. Moreover, alphaSYN is phosphorylated at S129 (phospho-serine-129 [PSer129]) in neuropathological lesions. Using our (Thy1)-[A30P]alphaSYN transgenic mouse model that develops age-dependent impairment in fear conditioning behavior, we investigated PSer129 immunostaining in the brain. We found distinct staining patterns using new, sensitive monoclonal antibodies. Somal and nuclear PSer129 immunoreactivity increased with age in hippocampal and cortical areas as well as the lateral/basolateral amygdalar nuclei and was present also in young, pre-symptomatic mice, but not wild-type controls. The tendency of PSer129 immunostaining to accumulate in the nucleus was confirmed in cell culture. (Thy1)-[A30P]alphaSYN transgenic mice further developed age-dependent, specific neuritic/terminal alphaSYN pathology in the medial parts of the central amygdalar nucleus and one of its projection areas, the lateral hypothalamus. Interestingly, this type of PSer129 neuropathology was thioflavine S negative, unlike the Lewy-like neuropathology present in the brain stem of (Thy1)-[A30P]alphaSYN mice. Thus, alphaSYN becomes phosphorylated in distinct parts of the brain in this alpha-synucleinopathy mouse model, showing age-dependent increases of nuclear PSer129 in cortical brain areas and the formation of neuritic/terminal PSer129 neuropathology with variable amyloid quality within the fear conditioning circuitry and the brain stem. The precursor of the non-Abeta component of Alzheimer's disease amyloid (NACP) (also known as alpha-synuclein) is a presynaptic terminal molecule that abnormally accumulates in the plaques of Alzheimer's disease (AD) and in the Lewy bodies (LBs) of Lewy body variant of AD, diffuse Lewy body disease, and Parkinson's disease. To better understand the distribution of NACP/alpha-synuclein and its fragments in the LB-bearing neurons and neurites, as well as to clarify the patterns of NACP/alpha-synuclein compartmentalization, we studied NACP/alpha-synuclein immunoreactivity using antibodies against the C-terminal, N-terminal, and NAC regions after Proteinase K and formic acid treatment in the cortex of patients with LBs. Furthermore, studies of the subcellular localization of NACP/alpha-synuclein within LB-bearing neurons were performed by immunogold electron microscopy. These studies showed that the N-terminal antibody immunolabeled the LBs and dystrophic neurites with great intensity and, to a lesser extent, the synapses. In contrast, the C-terminal antibody strongly labeled the synapses and, to a lesser extent, the LBs and dystrophic neurites. Whereas Proteinase K treatment enhanced NACP/alpha-synuclein immunoreactivity with the C-terminal antibody, it diminished the N-terminal NACP/alpha-synuclein immunoreactivity. Furthermore, formic acid enhanced LB and dystrophic neurite labeling with both the C- and N-terminal antibodies. In addition, whereas without pretreatment only slight anti-NAC immunoreactivity was found in the LBs, formic acid pretreatment revealed an extensive anti-NAC immunostaining of LBs, plaques, and glial cells. Ultrastructural analysis revealed that NACP/alpha-synuclein immunoreactivity was diffusely distributed within the amorphous electrodense material in the LBs and as small clusters in the filaments of LBs and neurites. These results support the view that aggregated NACP/alpha-synuclein might play an important role in the pathogenesis of disorders associated with LBs. Hallervorden-Spatz syndrome (HSS) is a rare autosomal recessive disorder clinically characterized by extrapyramidal signs and progressive dementia. In a typical case, the clinical symptoms become apparent during late childhood, and usually the course is protracted over a decade or more. We recently had an opportunity to study the brains of two cases of HSS with a clinical course of over 30 years. Case 1 was a 44-year-old female and case 2 was a 37-year-old male. Grossly, the brains showed severe fronto-temporal lobar atrophy with abundant spheroids and mild iron deposits in the globus pallidus, associated with features of motor neuron disease. In addition, there was diffuse sponginess in the atrophic cortex as well as widespread Alzheimer's neurofibrillary tangles (NFTs) and Lewy bodies (LBs) in the cortical and subcortical regions, including the spinal cord. Ultrastructurally, NFTs were composed of paired helical filaments, and LBs of central dense cores with radiating fibrils. Discrete immunostaining was demonstrated in NFTs and neuropil threads with various antibodies against phosphorylated tau, and in LBs with antibody against alpha-synuclein. In addition, diffuse, overlapping immunoreactivity of alpha-synuclein and phosphorylated tau was seen within the cytoplasm of many neurons. However, when LBs and NFTs coexisted within the same neurons, they were clearly segregated. The findings of our present cases as well as those reported in the literature may indicate that simultaneous and extensive occurrence of abnormal phosphorylation of tau and accumulation of alpha-synuclein may constitute cardinal pathological features of HSS with protracted clinical course. Progressive supranuclear palsy (PSP) is a neurodegenerative tauopathy characterized by Parkinsonism, vertical gaze palsy, and early falls. Lewy bodies (LBs) are detected in approximately 10% of PSP cases, but there is little information on the relationship of LBs to tau pathology. We determined the frequency of LBs in a large series of autopsy-confirmed cases of PSP and studied the density and distribution of LBs, including Parkinson disease stage, in cases with LBs (PSP/LBD). PSP/LBD was compared with pure LB disease (LBD), including assessment of neuronal loss in key brainstem nuclei. Immunohistochemistry for alpha-synuclein revealed LBs in 31 of 290 PSP cases (11%). One case had multiple system atrophy in addition to PSP and was excluded from further study along with 2 PSP/LBD cases with concurrent Alzheimer disease. The 29 cases of PSP/LBD were compared with 30 cases of PSP and 24 cases of LBD. The age, sex, brain weight, Braak neurofibrillary tangle (NFT) stage, as well as counts of NFTs and senile plaques were not different among PSP, LBD, and PSP/LBD, but disease duration was longer in LBD. The Parkinson disease stage was similar, but the density of LBs in most subcortical nuclei tended to be greater in LBD than in PSP/LBD. In contrast, substantia nigra neuronal loss was greater in PSP/LBD than both PSP and LBD. Double immunostaining demonstrated alpha-synuclein and tau in different neurons with few exceptions. The findings suggest that LBs in PSP are similar in distribution to those in LBD and independent of tau pathology. The greater density of LBs in LBD compared with PSP/LBD may be the result of longer disease duration in LBD, whereas greater neuronal loss in the substantia nigra in PSP/LBD may be the result of vulnerability of this brain region to both disease processes. The major protein constituent of Lewy bodies (LBs), the pathological hallmark of Parkinson disease and dementia with Lewy bodies, is considered to be alpha-synuclein, but other proteins, in particular the microtubule-associated protein tau, have been implicated in the pathogenesis of LBs. Tau is the major structural component of neurofibrillary tangles (NFTs). Both direct immunochemical studies of partially purified LBs and indirect immunohistochemical studies have suggested that LBs may contain tau, but most of these studies were based upon a single tau antibody, and immunologic cross-reactivity was not completely excluded. To gain insight into the relation between tau and alpha-synuclein in LBs, double immunostaining was performed in Lewy body cases with a rabbit polyclonal antibody to alpha-synuclein and a panel of monoclonal antibodies to phospho- and nonphospho-tau epitopes (Alz50, CP9, CP13, PG5, TG3, PHFI) that spanned the length of the tau molecule. Tau-immunoreactive LBs were present in the medulla in 80% of the cases, irrespective of Braak stage. All tau antibodies recognized at least some LBs, arguing against nonspecific antibody cross-reactivity. In most lesions the tau immunostaining was present at the periphery of the LB. The phospho-tau antibody, TG3, detected more LBs than any of the other tau antibodies. The proportion of LBs with tau immunoreactivity was greatest in neurons vulnerable to NETs, such as those in the locus ceruleus and basal nucleus of Meynert, and least in neurons resistant to NFTs, such as the dorsal motor nucleus of the vagus in the medulla. The present results suggest that tau may coaggregate with alpha-synuclein in LBs, especially in neuronal populations vulnerable to both NFTs and LBs. α-Synuclein is the major protein associated with Lewy body dementia, Parkinson's disease and multiple system atrophy. Since α-synuclein is present in the brain in physiological conditions as a presynaptic protein, it is crucial to characterize disease-associated modifications to develop an in vivo biomarker. With the aim to develop antibodies showing high specificity and sensitivity for disease-associated α-synuclein, synthetic peptides containing different amino acid sequences were used for immunization of mice. After generation of α-synuclein aggregates, ELISA and immunoblotting were used to test the specificity of antibodies. Tissue microarray sections originating from different human α-synucleinopathies were used to compare immunostaining with other, commercially available antibodies. Immunization of mice with the peptide TKEGVVHGVATVAE (amino acid 44-57 of α-synuclein) resulted in the generation of a monoclonal antibody (5G4), which was able to bind aggregated α-synuclein preparation in sandwich ELISA or coated on magnetic beads. 5G4 proved to be superior to other antibodies in comparative immunohistochemical studies by revealing more widespread and distinct α-synuclein pathology. Immunoblotting of human brain tissue revealed an additional band seen in dementia with Lewy bodies, whereas the band representing monomeric α-synuclein was very weak or lacking. In summary, the 5G4 antibody is most promising for re-evaluation of archival material and may offer new perspective for the development of in vivo diagnostic assays for detecting disease-associated α-synuclein in body fluids. BACKGROUND: Dementia is a frequent complication of idiopathic parkinsonism or PD, usually occurring later in the protracted course of the illness. The primary site of neuropathologic change in PD is the substantia nigra, but the neuropathologic and molecular basis of dementia in PD is less clear. Although Alzheimer's pathology has been a frequent finding, recent advances in immunostaining of alpha-synuclein have suggested the possible importance of cortical Lewy bodies (CLBs) in the brains of demented patients with PD. METHODS: The brains of 22 demented and 20 nondemented patients with a clinical and neuropathologic diagnosis of PD were evaluated with standard neuropathologic techniques. In addition, CLBs and dystrophic neurites were identified immunohistochemically with antibodies specific for alpha-synuclein and ubiquitin; plaques and tangles were identified by staining with thioflavine S. Associations between dementia status and pathologic markers were tested with logistic regression. RESULTS: CLBs positive for alpha-synuclein are highly sensitive (91%) and specific (90%) neuropathologic markers of dementia in PD and slightly more sensitive than ubiquitin-positive CLBs. They are better indicators of dementia than neurofibrillary tangles, amyloid plaques, or dystrophic neurites. CONCLUSION: CLBs detected by alpha-synuclein antibodies in patients with PD are a more sensitive and specific correlate of dementia than the presence of Alzheimer's pathology, which was present in a minority of the cases in this series. It is increasingly clear that the normal protein alpha-synuclein is in some manner closely associated with presynaptic components of select neuronal types within the adult human central nervous system (CNS) and, in addition, that in its pathologically altered state alpha-synuclein aggregates selectively in the form of filamentous inclusion bodies during certain progressive neurodegenerative disorders, such as familial and sporadic Parkinson's disease. By having the antibody AFshp raised specifically to alpha-synuclein to label Parkinson disease-specific Lewy bodies and Lewy neurites as well as synaptic boutons containing the unaltered protein, an initial attempt is made to map the overall distribution pattern and describe the staining behavior of the immunoreactive punctae in select regions of the prosencephalon. Neocortical immunolabeling is most prominent in the prodigious, but incompletely myelinated, association fields and faintest in the heavily myelinated primary motor and primary sensory fields, with the premotor and first order sensory association areas occupying an intermediate position. Of the thalamic grays evaluated, those containing powerfully myelinated fiber tracts (e.g. centrum medianum, habenular complex) show the weakest immunolabeling, whereas, less sturdily myelinated structures are highly immunoreactive. The fact that the immunostaining spectrum for normal alpha-synuclein is so broad, together with the fact that some thalamic sites actually are immunonegative leads to the following conclusions (1) alpha-synuclein, although present in the synaptic boutons of many nerve cells in the adult human CNS, is by no means ubiquitous there, and (2) neuronal types lacking the normal protein cannot generate the Parkinson's disease-specific filamentous pathology. alpha-Synuclein is a presynaptic protein recently identified as a specific component of Lewy bodies (LB) and Lewy neurites. The aim of this study was to assess the morphology and distribution of alpha-synuclein immunoreactivity in cases of dementia with LB (DLB), and to compare alpha-synuclein with ubiquitin immunostaining. We examined substantia nigra, paralimbic regions (entorhinal cortex, cingulate gyrus, insula and hippocampus), and neocortex (frontal and occipital association cortices) with double alpha-synuclein and ubiquitin immunostaining in 25 cases meeting neuropathological criteria for DLB. alpha-Synuclein immunostaining was more specific than ubiquitin immunostaining in that it differentiated LB from globose tangles. It was also slightly more sensitive, staining 4-5% more intracytoplasmic structures, especially diffuse alpha-synuclein deposits that were ubiquitin negative. In addition to LB, alpha-synuclein staining showed filiform and globose neurites in the substantia nigra, CA2-3 regions of the hippocampus, and entorhinal cortex. A spectrum of alpha-synuclein staining was seen in substantia nigra: from diffuse "cloud-like" inclusions to aggregated intracytoplasmic inclusions with variable ubiquitin staining to classic LB. We hypothesize that these represent different stages in LB formation. |
333 | Which are the main causes of fetal echogenic bowel? | Fetal echogenic bowel is mainly associated to feto-maternal, intramniotic bleeding but in several cases it is linked to cystic fibrosis, cytomegalovirus (CMV), herpes simplex virus and other viral infections and fetal aneuploidy. | [7474061, 18577682, 10419606, 20932506, 14663844, 19921962, 20059439, 8633653, 22990134, 18417974, 11169342, 17364293, 10912967, 21606744, 10550877, 8142051, 9664617, 10590441, 14626795, 22378220, 8538346, 18254450, 22589170, 11717628, 1415421, 10364670, 12835583] | 440 | Congenital cytomegalovirus infection with oligohydramnios and echogenic bowel at 14 weeks' gestation. Fetal echogenic bowel has been reported as a normal variant in the second trimester, and has also been associated with an adverse fetal outcome, including cystic fibrosis (CF), an autosomal recessive genetic disease. Previous studies have reported that 3.3 to 13.3 per cent of fetuses with echogenic bowel discovered during the second trimester were affected with CF. Between 1994 and 1998 our laboratory tested 159 cases with echogenic bowel detected during a routine ultrasound examination. The ethnic/racial background of cases included Caucasian, African-American, Middle Eastern, Hispanic, Ashkenazi Jewish and Asian. We identified two CF fetuses (1.3 per cent) and eight fetuses with a single identifiable CF mutation (5 per cent) within this diverse population. These data indicated that the risk of CF in a fetus with echogenic bowel in this population was less than the 3.3 to 13.3 per cent prior risk currently used in most Bayesian calculations. Furthermore, the results suggested that specific risks for couples should be calculated using data specific for their ethnic or racial background. Based on our results, we recommend either amniocentesis for fetal CF studies or CF carrier screening of both parents when fetal echogenic bowel is detected as a 1.3 per cent risk of CF is considered high enough to warrant further testing. OBJECTIVE: To investigate the association between fetal echogenic bowel (FEB) during the second trimester and perinatal outcome. METHODS: A retrospective chart review of FEB during the second trimester over 3 years. RESULTS: A total of 56 women were identified of 9067 screened (0.6%) women. Forty-seven agreed to genetic counseling (84%). Of those, 22 (39%) agreed to an amniocentesis. There were three cases of trisomy 21, one case of trisomy 18 and one case of fetal CMV infection. Twelve fetuses had an adverse outcome (21%), with only three of them having an echogenic bowel as the only finding. CONCLUSIONS: In our study, almost 80% of the fetuses had an uncomplicated perinatal outcome. FEB was present as the only finding in only 5% of the fetuses with an adverse outcome. A potential association with placental abnormalities and a low prevalence of viral infections was observed. These findings may be of use in counseling parents. OBJECTIVE: Fetal echogenic bowel (FEB) is a soft marker found on second trimester sonography. Our main aim was to determine the outcome of infants who presented with FEB and secondarily to identify additional sonographic findings that might have clinical relevance for the prognosis. DESIGN: We reviewed all pregnancies in which the diagnosis FEB was made in our Fetal Medicine Unit during 2009-2010 (N=121). We divided all cases into five groups according to additional sonographic findings. Group 1 consisted of cases of isolated FEB, group 2 of FEB associated with dilated bowels, group 3 of FEB with one or two other soft markers, group 4 of FEB with major congenital anomalies or three or more other soft markers, and group 5 consisted of FEB with isolated intrauterine growth restriction (IUGR). RESULTS: Of 121 cases, five were lost to follow-up. Of the remaining 116 cases, 48 (41.4%) were assigned to group 1, 15 (12.9%) to group 2, 15 (12.9%) to group 3, 27 (23.2%) to group 4, and 11 (9.5%) to group 5. The outcome for group 1 was uneventful. In group 2 and 3, two anomalies, anorectal malformation and cystic fibrosis, were detected postnatally (6.7%). In group 4, mortality and morbidity were high (78% resp. 22%). Group 5 also had high mortality (82%) and major morbidity (18%). CONCLUSIONS: If FEB occurs in isolation, it is a benign condition carrying a favourable prognosis. If multiple additional anomalies or early IUGR are observed, the prognosis tends to be less favourable to extremely poor. We describe some fetal ultrasound findings associated with intrauterine cytomegalovirus (CMV) infection. We report a 38-year-old gravida 3, para 2 at 16 weeks of gestation who underwent ultrasound examination for anomaly screening. The scan revealed an extensive irregular echogenic area in the fetal brain, especially at the level of lateral ventricles, suggestive of intraventricular and cerebral hemorrhage. Cardiomegaly, hepatomegaly, and mild ascites as well as an echogenic bowel were demonstrated. Abnormal chromosomes and hemoglobin Bart disease were excluded by analysis of fetal blood. Follow-up ultrasound at 20 weeks of gestation showed frank hydrops fetalis, and termination of the pregnancy was performed based on the couple's decision, giving stillbirth to a male fetus weighing 450 g. Autopsy findings showed intracerebral hemorrhage (right cerebral hemisphere) and hydrops fetalis with hepatosplenomegaly. Microscopic investigation showed typical changes of CMV infection in several organs, including brain, thyroid gland, lung, liver, kidney, heart, pancreas, and placenta. Sonographically, the combination of hydrops fetalis, cerebral hemorrhage, and hyperechoic bowel should raise the possibility of a CMV infection, particularly in cases with no obvious cause of hydrops fetalis. 1. Ultrasound Obstet Gynecol. 2000 Nov;16(6):510-4. doi: 10.1046/j.1469-0705.2000.00322.x. Author information: (1)Department of Obstetrics and Gynecology, Sahlgrenska University Hospital, Göteborg, Sweden. [email protected] OBJECTIVE: To assess the relationship between intra-amniotic bleeding and fetal echogenic bowel. METHODS: Comprehensive fetal ultrasound examinations were done before and 12 hours after fetal transfusions. Follow-up ultrasound examinations were done weekly in 28 fetuses with intra-amniotic bleeding. Hyperechogenic bowel was diagnosed when the echogenicity of fetal bowel was similar to that of bone. Postpuncture bleeding was identified when a stream of echogenic material from the cord into the amniotic space was seen, lasting at least 60 seconds. RESULTS: None of the fetuses had echogenic bowel before initial transfusions. Intra-amniotic bleeding was followed by bowel echogenicity in seven of 28 fetuses within the first 12 hours after bleeding episodes. Echogenic bowel remained in five fetuses 2 weeks after the bleeding episodes. In three fetuses, echogenic bowel was still seen 4 weeks later. CONCLUSION: Intra-amniotic bleeding can lead to echogenic bowel. OBJECTIVE: Fetal echogenic bowel has been observed in fetuses with meconium peritonitis, cystic fibrosis, aneuploidy, congenital viral infection and intrauterine growth restriction. The pathogenesis of echogenic bowel is unknown, but it may be attributed to bowel ischemia. Fetuses affected by homozygous alpha-thalassemia-1 are severely anemic and hypoxic. We investigated the incidence of echogenic bowel in these hypoxic fetuses in the first and second trimesters. DESIGN: Prospective observational study. SUBJECTS: Women referred for the prenatal diagnosis of homozygous alpha-thalassemia-1 before 24 weeks' gestation. METHODS: All subjects had one or more abdominal and/or vaginal ultrasound examination between 12 and 24 weeks' gestation. Echogenic bowel was diagnosed if the bowel appeared either isoechogenic or more echogenic than the bone. RESULTS: Between March 1997 and July 1998, 126 pregnancies were studied. Thirty-six fetuses were confirmed to be affected by homozygous alpha-thalassemia-1, and 11 of them (31%, 95% CI 16-48%) had echogenic bowel. These observations were made before the invasive test results were available. None of the fetuses unaffected by homozygous alpha-thalassemia-1 had echogenic bowel. CONCLUSION: There is a strong association between homozygous alpha-thalassemia-1 and echogenic bowel. The pathogenesis is unknown. Speculations include bowel hypoperistalsis or bowel wall edema due to severe anemia and hypoxia. Though echogenic fetal bowel has been associated with meconium ileus and/or peritonitis, it may be a normal finding in the second trimester. The purpose of this study is to determine which characteristics might distinguish fetuses ultimately having abnormal outcomes in a population at low risk for cystic fibrosis. Seven fetuses with echogenic bowel were identified: 5 fetuses < or = 20 weeks gestation (group 1) and 2 fetuses 20-25 weeks gestation (group 2) at diagnosis. Four of 5 group 1 fetuses had resolution of the echogenic bowel during the second trimester. One group 2 fetus had a persistent mass associated with growth deficiency and trisomy 18. The neonatal bowel evaluation was normal in the remaining 2 fetuses although echogenic findings persisted into the third trimester. In a low-risk population, echogenic bowel usually resolves without neonatal sequelae. Even when persistent into the third trimester, echogenic bowel does not uniformly herald an abnormal outcome. Echogenic bowel coexistent with other abnormalities (such as growth deficiency or structural malformations) may be a comarker for aneuploidy. OBJECTIVE: The objective was to evaluate the incidence of gastrointestinal abnormalities amongst those fetuses with antenatally diagnosed echogenic bowel (EB). MATERIALS AND METHODS: A retrospective review of all cases delivered from April 2002 to March 2003 with antenatally diagnosed EB was conducted. This was defined as bowel that appeared as echogenic as (if not greater than) the iliac bone on a real-time image. The postnatal outcomes with regard to gastrointestinal abnormalities, till their discharge, were noted. RESULTS: Of the 13,941 patients delivered, there were 70 cases with antenatally diagnosed EB, giving an incidence of 70/13,941 or 0.50%. Of these, 6 defaulted follow-up and 1 had a mid-trimester termination of pregnancy at 21 weeks' gestation for social reasons. Of the remaining 63 cases with EB, 2 were stillbirths at 31 weeks and 35 weeks of gestation, respectively. Three fetuses (3/63 or 4.76%) were diagnosed with gastrointestinal abnormalities. Meconium plug syndrome was diagnosed postnatally in 2 cases, of which, 1 resolved with conservative management while the other required an emergency laparotomy. Intestinal atresia was diagnosed in the postmortem of one of the stillbirths. There was evidence of intrauterine growth retardation (IUGR) in both the stillbirth and the fetus that had required laparotomy. None of the 3 fetuses exhibited clinical features of aneuploidy. CONCLUSION: As the quoted background risk for gastrointestinal pathology is 0.23%, an increased incidence (4.76%) is observed in those fetuses found to have antenatal EB. It is possible that the presence of IUGR is associated with a worse prognosis. Further prospective studies are needed to verify this association. BACKGROUND: An increased frequency of hyperechogenic bowel on ultrasound has been reported in fetuses with cystic fibrosis (CF) and trisomy-21. However, the diagnostic application of this observation has been hampered by the absence of a means of measuring echogenicity. METHODS: We devised an ultrasonic grading system in which echogenicity was quantified by linear gain reduction and comparison with fetal iliac crest. From 7400 second-trimester ultrasound referrals, 145 patients were identified as having a fetus with abnormally echogenic bowel. They were offered genetic counselling, parental and (if appropriate) CF carrier testing, and amniocentesis for karyotype and CF status if parents were informative. Follow-up was to 4 months of age. FINDINGS: Of 40 fetuses with mild increase in bowel sonodensity (grade 1), none had CF or aneuploidy. Of 81 patients identified with a moderate increase (grade 2), 2 had trisomy 21 and 2 had CF. And of 24 pregnancies with a pronounced increase (grade 3), 5 had CF and 6 had trisomy-21. INTERPRETATION: Parental CF carrier testing and amniocentesis to identify aneuploidy or fetal CF status has a high positive ascertainment rate in fetuses with echogenic bowel grades 2 and 3. Echogenic bowel is diagnosed in 0.2% to 1.4% of second trimester ultrasonographic examinations. This finding occurs as a normal variant in the second trimester but also has been associated with several pathologic conditions that include cystic fibrosis, chromosomal abnormalities and in utero infection with cytomegalovirus and toxoplasmosis. Ultrasound assessment of echogenic bowel is usually subjective by comparing the echogenicity with adjacent bone or liver. The diagnosis of fetal echogenic bowel in the second trimester has significant implications for prenatal management. Fetal echogenic bowel should be considered an important marker of placental damage. This finding in the second trimester is strongly associated with adverse pregnancy outcome due to utero-placental insufficiency, particularly in women with elevated maternal serum alpha-fetoprotein concentration due to severe feto-maternal bleeding. This review focuses on the definition and diagnosis of this entity and problems raised by echogenic bowel due to subjectivity of the diagnosis. It also includes the pathophysiology in the different conditions and the prevalence of each condition. Based on this review, we suggest the evaluation that is needed, as well as the recommendations to follow-up, during the remaining term of pregnancy according to the literature. OBJECTIVE: To investigate perinatal outcomes of fetal echogenic bowel (FEB). METHOD: This is a retrospective observational study of FEB cases from Jan 2005-Dec 2010. Data from ultrasound and fetal medicine investigations, uterine artery Doppler (UAD), intra-partum care and neonatal outcome were obtained from Fetal Medicine, Obstetric and Neonatal Databases. RESULTS: There were 139 cases presenting at 21(+5) (15(+1) -35(+5) ) weeks gestation. Overall, 106/139 (76.2%) were live born (LB), 8/139 (5.8%) were complicated by intra-uterine deaths (IUD), 11/139 (7.9%) had termination of pregnancy (TOP) and 14/139 (10.1%) were lost to follow-up after 28 weeks gestation. Six had chromosomal/genetic abnormalities, two had congenital cytomegalovirus, none had cystic fibrosis.Uterine artery Doppler was normal in 106/130 (81.5%) cases. In this group, there were no cases of fetal growth restriction (FGR), 95/106 (89.6%) were LB, 1/106 (0.94%) had an IUD. In the abnormal UAD group, 17/24 (70.1%) developed FGR, 11/24 (45.8%) were LB, 4/24 (16.7%) had TOP, 7/24 (29.2%) had IUD.In total, 20/106 (18.9%) live births were admitted for specialist neonatal care, 12/20 (60%) for prematurity. Only one had primary bowel pathology. CONCLUSION: Pregnancies with FEB and screen positive UAD are at risk of adverse perinatal outcome. Primary bowel pathology is rare following the finding of FEB. OBJECTIVE: The purpose of this study was to determine the incidence of cystic fibrosis, aneuploidy, and intrauterine infection with toxoplasmosis and cytomegalovirus in second-trimester fetuses with the sonographic finding of echogenic bowel. STUDY DESIGN: All cases of echogenic bowel that were diagnosed in our ultrasound unit from 1993 to 2000 were identified. Only cases in which bowel echogenicity was as bright as bone with no associated major fetal anomalies were included. Patients who were referred from other hospitals were excluded. Echogenicity was classified as focal or multifocal. Fetal karyotypes, cystic fibrosis carrier testing, and maternal serologic test results were determined. RESULTS: One hundred seventy-five fetuses in 171 pregnancies met inclusion criteria. Cystic fibrosis mutations were identified in 7 of 138 mothers (5%) and 9 of 86 fathers (10.5%) who were tested. Five fetuses were affected with cystic fibrosis. Fetal karyotype was obtained in 139 cases, and autosomal trisomy was diagnosed in 5 cases (3.6%). One hundred sixty-six patients were tested for toxoplasmosis, and 111 patients were tested for cytomegalovirus. There were no cases of congenital toxoplasmosis. There was maternal serologic and fetal pathologic evidence of cytomegalovirus infection in 1 case. In all cases of cystic fibrosis and aneuploidy, echogenicity was multifocal; in the case of cytomegalovirus, echogenicity was focal. CONCLUSION: In our population, mid-trimester fetal echogenic bowel was associated with a high prevalence of cystic fibrosis, aneuploidy, and cytomegalovirus (11/175 fetuses [6.3%]). This information should be considered when counseling patients after mid-trimester echogenic bowel is diagnosed. Previous studies cite different possible etiologies for fetal echogenic bowel (FEB). The purpose of this study was to evaluate the possible etiologies for second-trimester FEB, and to provide clinical guidelines for evaluation of this finding. The study included 79 patients diagnosed with FEB in the second trimester. Fifteen cases (19%) were associated with maternal vaginal bleeding. Of these, 12 patients underwent amniocentesis, 9 of which had visible blood products in the amniotic fluid. Seven cases (8.9%) had associated severe malformation. Seven other cases (8.9%) were noted in multifetal pregnancies. Five fetuses (6.3%) had evidence of bowel obstruction or perforation not associated with cystic fibrosis (CF). Chromosomal aberrations were found in 5 fetuses (6.3%). Intrauterine infection with cytomegalovirus, herpes simplex virus, varicella-zoster virus, or parvovirus B-19 was documented in 5 patients (6.3%). Three cases (3.8%) were associated with subsequent unexplained stillbirth. Two fetuses (2.5%) were found to be affected by CF. Finally, in 30 cases (38%), no obvious reason for FEB was found. We conclude that the evaluation of second-trimester FEB should include targeted ultrasound for associated malformations, infectious studies, DNA analysis for CF mutations, amniocentesis for chromosomal analysis and evaluation of the amniotic fluid for degraded blood products, and an autopsy in cases of stillbirth. Even when no apparent reason is found, pregnancies should be considered at high risk for poor outcome. |
334 | How does trimetazidine affect intracellular kinase signaling in the heart? | Trimetazidine activates AMPK in diabetic myocardium. Trimetazidine when administered before reperfusion results in activation of p38 mitogen-activated protein kinase and Akt signaling. Trimetazidine when administered during reperfusion does not affect p38MAPK and JNK activation. | [19546072, 20167841, 20383170, 15616764] | 441 | BACKGROUND: Trimetazidine is an anti-ischemic agent with cardioprotective effects. The purpose of this double-blind, controlled, prospective randomized study was to investigate the possible effects of the preoperative use of trimetazidine on the biochemical markers of myocardial injury during open heart surgery and to determine if it has any myocardial protective effects. METHODS: Thirty patients undergoing coronary artery bypass grafting surgery, received either trimetazidine (study group, n = 15) or not (control group, n = 15). Pretreatment began 2 weeks before the operation with trimetazidine (60 mg/day orally), and the control group received no medication. We measured the levels of serum creatine kinase (CK), CK isoenzyme MB (CK-MB), myoglobin, and troponin T in venous blood samples obtained before and after the operation to evaluate the effect of this drug against myocardial damage. We also took serial blood samples from the radial artery and the coronary sinus before the institution of cardiopulmonary bypass (CPB) and at 2 and 15 minutes after the removal of the cross-clamp to measure lactate levels and calculate the lactate extraction of the myocardium. RESULTS: Postoperative levels of myoglobin, troponin T, CK, and CK-MB were significantly lower in the trimetazidine group than in the control group (P < .05). There was also a significant difference in the values for the lactate extraction calculation between the groups at minute 2 after the removal of the cross-clamp (P < .05). CONCLUSION: We conclude that pretreatment with trimetazidine has some beneficial effects in protecting the myocardium and decreasing myocardial injury during the cardioplegic arrest period in open heart surgery without affecting postoperative hemodynamics. AIM: To investigate the influence of trimetazidine, which is known to be an antioxidant and modulator of metabolism, on cardiac function and the development of diabetic cardiomyopathy in db/db mouse. METHODS: Trimetazidine was administered to db/db mice for eight weeks. Cardiac function was measured by inserting a Millar catheter into the left ventricle, and oxidative stress and AMP-activated protein kinase (AMPK) activity in the myocardium were evaluated. RESULTS: Untreated db/db mice exhibited a significant decrease in cardiac function compared to normal C57 mice. Oxidative stress and lipid deposition were markedly increased in the myocardium, concomitant with inactivation of AMPK and increased expression of peroxisome proliferator-activated receptor coactivator-1 alpha (PGC-1 alpha). Trimetazidine significantly improved systolic and diastolic function in hearts of db/db mice and led to reduced production of reactive oxygen species and deposition of fatty acid in cardiomyocytes. Trimetazidine also caused AMPK activation and reduced PGC-1 alpha expression in the hearts of db/db mice. CONCLUSION: The data suggest that trimetazidine significantly improves cardiac function in db/db mice by attenuating lipotoxicity and improving the oxidation status of the heart. Activation of AMPK and decreased expression of PGC-1 alpha were involved in this process. Furthermore, our study suggests that trimetazidine suppresses the development of diabetic cardiomyopathy, which warrants further clinical investigation. The present study investigated the tolerance of the isolated rat heart to ischemia-reperfusion after administration of trimetazidine (TMZ) at different experimental phases, as well as the possible involvement of p38 MAPK and JNKs in this response. Isolated rat hearts were perfused in Langendorff mode. Untreated hearts after stabilization (S) were subjected to 20 min of zero-flow global ischemia (I) and 45 min of reperfusion (R), (NORM), n = 9. TMZ (10(-5) M) was administered (in the perfusate): a) only at S phase, (TMZ-STAB), n = 8, b) only at R, (TMZ-REP), n = 8 and c) during both S and R, (TMZ-STAB+REP), n = 8. Recovery of left ventricular developed pressure at 45 min of R (Rec) was significantly higher in TMZ-STAB and TMZ-STAB+REP and LDH release was lower in TMZ-STAB+REP and TMZ-STAB than NORM, [1153.2 (121.0) and 1152.1 (86.8) vs 1573.5 (138.2), P < 0.05]. TMZ induced cardioprotection did not involve p38 MAPK and JNKs. Phospho-p38 MAPK and JNKs levels after I/R were not changed with TMZ treatment. In TMZ-REP, Rec and LDH release were similar to NORM, but the rate of functional recovery (ratio of Rec at 10 min of R to Rec) was 86.7% (13.3) for TMZ-REP vs 53.8% (7.7) for NORM, P < 0.05. This effect was associated with decreased myocardial lactate content early at reperfusion. In conclusion, preischemic administration of TMZ protects against I/R injury while TMZ given only at reperfusion accelerates recovery of function without reducing the extent of injury. |
335 | Which is the enzymatic activity of the myotubularin family of proteins? | The myotubularin family of proteins are lipid inositol phosphatases | [11846405, 12925573, 19325702, 21175430, 12045210, 23114011, 21510942, 22578719, 14690594, 11733541, 23857703, 22647598, 15998640, 12829232, 12118066, 20736309, 16289848, 20188094, 16262718, 11275328, 12554688, 23086420, 12788949, 16787938, 12018406, 21372139, 17346927, 16410353, 16914545, 12646134, 23818870, 16828287] | 442 | Myotubularin-related genes define a novel highly conserved family of eukaryotic proteins of at least 11 human members. The hMTM1 gene that codes for myotubularin is mutated in X-linked myotubular myopathy, a severe congenital disease. Recently, we and others have characterized myotubularin as a potent and specific phosphatidylinositol 3-phosphate 3-phosphatase. In the present study we investigated the lipid phosphatase activity and the subcellular localization of two other members of the family, hMTMR2 protein that is mutated in the demyelinating neuropathy Charcot-Marie-Tooth type 4B and the FYVE-finger containing hMTMR3 protein. Our results show that both proteins are potent phosphatidylinositol 3-phosphate 3-phosphatases either in vitro or in yeast where they interfered with vesicular trafficking. Their localization is mainly cytoplasmic, with however strong labeling of Rac-inducible plasma membrane ruffles. The fact that the ubiquitously expressed hMTM1 and hMTMR2 genes are involved in different pathologies indicates that despite their shared enzymatic activity, they are not functionally redundant, at least in certain cell types. This might be explained by subtle differences in expression and/or in recruitment and regulation at their specific site of action. The myotubularin family is a large eukaryotic group within the tyrosine/dual-specificity phosphatase super-family (PTP/DSP). Among the 14 human members, three are mutated in genetic diseases: myotubular myopathy and two forms of Charcot-Marie-Tooth neuropathy. We present an analysis of the myotubularin family in sequenced genomes. The myotubularin family encompasses catalytically active and inactive phosphatases, and both classes are well conserved from nematode to man. Catalytically active myotubularins dephosphorylate phosphatidylinositol 3-phosphate (PtdIns3P) and PtdIns3,5P2, leading to the production of PtdIns and PtdIns5P. This activity may be modulated by direct interaction with catalytically inactive myotubularins. These phosphoinositides are signaling molecules that are notably involved in vacuolar transport and membrane trafficking. Myotubularins are thus proposed to be implicated in these cellular mechanisms, and recent observations on myotubularins homologues in the nematode Caenorhabditis elegans indicate a role in endocytosis. BACKGROUND: It has been shown that mutations in at least four myotubularin family genes (MTM1, MTMR1, 2 and 13) are causative for human neuromuscular disorders. However, the pathway and regulative mechanism remain unknown. METHODOLOGY/PRINCIPAL FINDINGS: Here, we reported a new role for Mtmr8 in neuromuscular development of zebrafish. Firstly, we cloned and characterized zebrafish Mtmr8, and revealed the expression pattern predominantly in the eye field and somites during early somitogenesis. Using morpholino knockdown, then, we observed that loss-of-function of Mtmr8 led to defects in somitogenesis. Subsequently, the possible underlying mechanism and signal pathway were examined. We first checked the Akt phosphorylation, and observed an increase of Akt phosphorylation in the morphant embryos. Furthermore, we studied the PH/G domain function within Mtmr8. Although the PH/G domain deletion by itself did not result in embryonic defect, addition of PI3K inhibitor LY294002 did give a defective phenotype in the PH/G deletion morphants, indicating that the PH/G domain was essential for Mtmr8's function. Moreover, we investigated the cooperation of Mtmr8 with PI3K in actin filament modeling and muscle development, and found that both Mtmr8-MO1 and Mtmr8-MO2+LY294002 led to the disorganization of the actin cytoskeleton. In addition, we revealed a possible participation of Mtmr8 in the Hedgehog pathway, and cell transplantation experiments showed that Mtmr8 worked in a non-cell autonomous manner in actin modeling. CONCLUSION/SIGNIFICANCE: The above data indicate that a conserved functional cooperation of Mtmr8 with PI3K regulates actin filament modeling and muscle development in zebrafish, and reveal a possible participation of Mtmr8 in the Hedgehog pathway. Therefore, this work provides a new clue to study the physiological function of MTM family members. The MTM (myotubularin)/MTMR (myotubularin-related) protein family is comprised of 15 lipid phosphatases, of which nine members are catalytically active. MTMs are known to play a fundamental role in human physiology as gene mutations can give rise to X-linked myotubular myopathy or Charcot-Marie-Tooth disease, which manifest in skeletal muscle or in peripheral neurons respectively. Interestingly, studies have shown MTMR2 and MTMR5, two MTM family members, to be highly expressed in the testis, particularly in Sertoli and germ cells, and knockout of either gene resulted in spermatogenic defects. Other studies have shown that MTMR2 functions in endocytosis and membrane trafficking. In the testis, MTMR2 interacts and co-localizes with c-Src/phospho-Src-(Tyr⁴¹⁶), a non-receptor protein tyrosine kinase that regulates the phosphorylation state of proteins at the apical ES (ectoplasmic specialization), a unique type of cell junction found between Sertoli cells and elongating/elongated spermatids. In the present review, we highlight recent findings that have made a significant impact on our understanding of this protein family in normal cell function and in disease, with the emphasis on the role of MTMs and MTMRs in spermatogenesis. We also describe a working model to explain how MTMR2 interacts with other proteins such as c-Src, dynamin 2, EPS8 (growth factor receptor pathway substrate 8) and ARP2/3 (actin-related protein 2/3) at the apical ES and the apical TBC (tubulobulbar complex; tubular-like invaginations that function in the disassembly of the apical ES and in the recycling of its components) to regulate spermiation at late stage VIII of the seminiferous epithelial cycle. BACKGROUND: Autophagy is a ubiquitous cellular process responsible for the bulk degradation of cytoplasmic components through the autophagosomal-lysosomal pathway. In skeletal muscle, autophagy has been regarded as a key regulator for muscle mass maintenance, and its imbalance leads to sarcopenia. However, the underlying mechanism is poorly understood. RESULTS: In this study, we demonstrate that ceMTM3, a FYVE-domain containing myotubalarin family phosphatase, is required for the maintenance of muscle fibers by preventing excessive autophagy in Caenorhabditis elegans. Knockdown of ceMTM3 by using feeding-based RNA interference caused loss of muscle fibers accompanied by shortening of muscle cell and body size in aged C. elegans worms. This was preceded by the occurrence of excessive autophagy in the muscle and other tissues, which subsequently resulted in increased lysosomal activity and necrotic cell death. However, knockdown of ceMTM3 did not aggravate the abnormalities of muscle wasting in autophagy-deficient atg-18 mutant worms. CONCLUSIONS: Our data suggest an important role of ceMTM3 in regulating autophagy and maintaining muscle fibers. This study may have clinical implications for prevention and treatment of sarcopenia. Myotubularin related protein 2 (MTMR2) is a member of the myotubularin family of phosphoinositide lipid phosphatases. Although MTMR2 dephosphorylates the phosphoinositides PI(3)P and PI(3,5)P2, the phosphoinositide binding proteins that are regulated by MTMR2 are poorly characterized. In this study, phosphoinositide affinity chromatography coupled to mass spectrometry identified receptor mediated endocytosis 8 (RME-8) as a novel PI(3)P binding protein. RME-8 co-localized with the PI(3)P marker DsRed-FYVE, while the N-terminal region of RME-8 is required for PI(3)P and PI(3,5)P(2) binding in vitro. Depletion of PI(3)P by MTMR2 S58A or wortmannin treatment attenuated RME-8 endosomal localization and co-localization with EGFR on early endosomes. Our results suggest a model in which the localization of RME-8 to endosomal compartments is spatially mediated by PI(3)P binding and temporally regulated by MTMR2 activity. The myotubularin family of phosphoinositide phosphatases includes several members mutated in neuromuscular diseases or associated with metabolic syndrome, obesity, and cancer. Catalytically dead phosphatases regulate their active homologs by heterodimerization and potentially represent key players in the phosphatase-kinase balance. Although the enzymatic specificity for phosphoinositides indicates a role for myotubularins in endocytosis and membrane trafficking, recent findings in cellular and animal models suggest that myotubularins regulate additional processes including cell proliferation and differentiation, autophagy, cytokinesis, and cytoskeletal and cell junction dynamics. In this review, we discuss how myotubularins regulate such diverse processes, emphasizing newly identified functions in a physiological and pathological context. A better understanding of myotubularin pathophysiology will pave the way towards therapeutic strategies. Myotubularin-related proteins are a large subfamily of protein tyrosine phosphatases (PTPs) that dephosphorylate D3-phosphorylated inositol lipids. Mutations in members of the myotubularin family cause the human neuromuscular disorders myotubular myopathy and type 4B Charcot-Marie-Tooth syndrome. The crystal structure of a representative member of this family, MTMR2, reveals a phosphatase domain that is structurally unique among PTPs. A series of mutants are described that exhibit altered enzymatic activity and provide insight into the specificity of myotubularin phosphatases toward phosphoinositide substrates. The structure also reveals that the GRAM domain, found in myotubularin family phosphatases and predicted to occur in approximately 180 proteins, is part of a larger motif with a pleckstrin homology (PH) domain fold. Finally, the MTMR2 structure will serve as a model for other members of the myotubularin family and provide a framework for understanding the mechanism whereby mutations in these proteins lead to disease. Myotubularin is the archetype of a family of highly conserved protein-tyrosine phosphatase-like enzymes. The myotubularin gene, MTM1, is mutated in the genetic disorder, X-linked myotubular myopathy. We and others have previously shown that myotubularin utilizes the lipid second messenger, phosphatidylinositol 3-phosphate (PI(3)P), as a physiologic substrate. We demonstrate here that the myotubularin-related protein MTMR2, which is mutated in the neurodegenerative disorder, type 4B Charcot-Marie-Tooth disease, is also highly specific for PI(3)P as a substrate. Furthermore, the MTM-related phosphatases MTMR1, MTMR3, and MTMR6 also dephosphorylate PI(3)P, suggesting that activity toward this substrate is common to all myotubularin family enzymes. A direct comparison of the lipid phosphatase activities of recombinant myotubularin and MTMR2 demonstrates that their enzymatic properties are indistinguishable, indicating that the lack of functional redundancy between these proteins is likely to be due to factors other than the utilization of different physiologic substrates. To this end, we have analyzed myotubularin and MTMR2 transcripts during induced differentiation of cultured murine C2C12 myoblasts and find that their expression is divergently regulated. In addition, myotubularin and MTMR2 enhanced green fluorescent protein fusion proteins exhibit overlapping but distinct patterns of subcellular localization. Finally, we provide evidence that myotubularin, but not MTMR2, can modulate the levels of endosomal PI(3)P. From these data, we conclude that the developmental expression and subcellular localization of myotubularin and MTMR2 are differentially regulated, resulting in their utilization of specific cellular pools of PI(3)P. Phosphatidylinositol (PtdIns) is a membrane phospholipid composed of diacylglycerol and a D-myo-inositol head group. In mammals, the hydroxyl groups at the D3, D4 and D5 positions of the inositol ring can be phosphorylated to yield seven phosphoinositide derivatives. PtdIns-3,5-bisphosphate [PtdIns(3,5)P2] is the most recently discovered species of phosphoinositide that is generated by the phosphorylation of PtdIns(3)P at the D5 position by PtdIns phosphate kinase and catabolized through the dephosphorylation by myotubularin family of phosphatases. Genetic and biochemical analyses of the enzymes metabolizing PtdIns(3,5)P2 have revealed that this phospholipid is involved in the control of endolysosomal systems and plays crucial roles in various mammalian tissues. In this article, we review the current state of knowledge of the metabolic/physiological functions of PtdIns(3,5)P2, and describe how disruption of these functions may contribute to human diseases. Charcot-Marie-Tooth disease type 4B (CMT4B) is a severe, demyelinating peripheral neuropathy characterized by distinctive, focally folded myelin sheaths. CMT4B is caused by recessively inherited mutations in either myotubularin-related 2 (MTMR2) or MTMR13 (also called SET-binding factor 2). MTMR2 encodes a member of the myotubularin family of phosphoinositide-3-phosphatases, which dephosphorylate phosphatidylinositol 3-phosphate (PI(3)P) and bisphosphate PI(3,5)P2. MTMR13 encodes a large, uncharacterized member of the myotubularin family. The MTMR13 phosphatase domain is catalytically inactive because the essential Cys and Arg residues are absent. Given the genetic association of both MTMR2 and MTMR13 with CMT4B, we investigated the biochemical relationship between these two proteins. We found that the endogenous MTMR2 and MTMR13 proteins are associated in human embryonic kidney 293 cells. MTMR2-MTMR13 association is mediated by coiled-coil sequences present in each protein. We also examined the cellular localization of MTMR2 and MTMR13 using fluorescence microscopy and subcellular fractionation. We found that (i) MTMR13 is a predominantly membrane-associated protein; (ii) MTMR2 and MTMR13 cofractionate in both a light membrane fraction and a cytosolic fraction; and (iii) MTMR13 membrane association is mediated by the segment of the protein which contains the pseudophosphatase domain. This work, which describes the first cellular or biochemical investigation of the MTMR13 pseudophosphatase protein, suggests that MTMR13 functions in association with MTMR2. Loss of MTMR13 function in CMT4B2 patients may lead to alterations in MTMR2 function and subsequent alterations in 3-phosphoinositide signaling. Such a mechanism would explain the strikingly similar phenotypes of patients with recessive mutations in either MTMR2 or MTMR13. Myotubularin, the phosphatase mutated in X-linked myotubular myopathy, was shown to dephosphorylate phosphatidylinositol 3-monophosphate (PtdIns3P) and was also reported to interact with nuclear transcriptional regulators from the trithorax family. We have characterized a panel of specific antibodies and investigated the subcellular localization of myotubularin. Myotubularin is not detected in the nucleus, and localizes mostly as a dense cytoplasmic network. Overexpression of myotubularin does not detectably affect vesicle trafficking in the mammalian cells investigated, in contrast to previous observations in yeast models. Both mutation of a key aspartate residue of myotubularin and dominant activation of Rac1 GTPase lead to the recruitment of myotubularin to specific plasma membrane domains. Localization to Rac1-induced ruffles is dependent on the presence of a domain highly conserved in the myotubularin family (that we named RID). We thus propose that myotubularin may dephosphorylate a subpool of PtdIns3P (or another related substrate) at the plasma membrane. Phosphatidylinositol 3-phosphate [PtdIns(3)P] regulates endocytic trafficking and the sorting of receptors through early endosomes, including the rapid recycling of transferrin (Tfn). However, the phosphoinositide phosphatase that selectively opposes this function is unknown. The myotubularins are a family of eight catalytically active and six inactive enzymes that hydrolyse PtdIns(3)P to form PtdIns. However, the role each myotubularin family member plays in regulating endosomal PtdIns(3)P and thereby endocytic trafficking is not well established. Here, we identify the myotubularin family member MTMR4, which localizes to early endosomes and also to Rab11- and Sec15-positive recycling endosomes. In cells with MTMR4 knockdown, or following expression of the catalytically inactive MTMR4, MTMR4(C407A), the number of PtdIns(3)P-decorated endosomes significantly increased. MTMR4 overexpression delayed the exit of Tfn from early endosomes and its recycling to the plasma membrane. By contrast, expression of MTMR4(C407A), which acts as a dominant-negative construct, significantly accelerated Tfn recycling. However, in MTMR4 knockdown cells Tfn recycling was unchanged, suggesting that other MTMs might also contribute to recycling. MTMR4 regulated the subcellular distribution of Rab11 and, in cells with RNAi-mediated knockdown of MTMR4, Rab11 was directed away from the pericentriolar recycling compartment. The subcellular distribution of VAMP3, a v-SNARE protein that resides in recycling endosomes and endosome-derived transport vesicles, was also regulated by MTMR4. Therefore, MTMR4 localizes at the interface of early and recycling endosomes to regulate trafficking through this pathway. The human neuromuscular diseases X-linked myotubular myopathy and Charcot-Marie-Tooth disease type 4B are caused by mutations in myotubularin family proteins. The myotubularins are a unique subfamily of protein tyrosine phosphatases that utilize inositol phospholipids, rather than phosphoproteins, as substrates. Recent structural studies, including the first crystal structure of a myotubularin family protein, have defined the structural features that are characteristic of the family and revealed the molecular basis of their unique substrate specificity. Interestingly, the myotubularin family contains a subgroup of proteins that are catalytically inactive. Recent biochemical studies have established that the inactive myotubularins function as adaptors for the active members and play an important regulatory role within the family. Autophagy initiation is strictly dependent on phosphatidylinositol 3-phosphate (PI3P) synthesis. PI3P production is under tight control of PI3Kinase, hVps34, in complex with Beclin-1. Mammalian cells express several PI3P phosphatases that belong to the myotubularin family. Even though some of them have been linked to serious human diseases, their cellular function is largely unknown. Two recent studies indicate that PI3P metabolism involved in autophagy initiation is further regulated by the PI3P phosphatases Jumpy and MTMR3. Additional pools of PI3P, upstream of mTOR and on the endocytic pathway, may modulate autophagy indirectly, suggesting that other PI3P phosphatases might be involved in this process. This review sums up our knowledge on PI3P phosphatases and discusses the recent progress on their role in autophagy. The myotubularins (MTMs) constitute a large family of phosphoinositide lipid 3-phosphatases with specificity for PtdIns3P and PtdIns (3,5)P2. Mutations in MTM proteins are associated with inherited conditions such as myotubular myopathy and Charcot-Marie-Tooth syndrome. The substrate lipids are known to be regulators of the endosomal pathway through recruitment of specific effector proteins. Hydrolysis of PtdIns (3,5)P2 provides a biosynthetic pathway to the production of PtdIns5P, which itself can allosterically activate MTMs. We review the properties of this intriguing family of proteins and discuss potential physiological functions that include regulation of the endocytic pathway. The myotubularin-related genes define a large family of eukaryotic proteins, most of them initially characterized by the presence of a ten-amino acid consensus sequence related to the active sites of tyrosine phosphatases, dual-specificity protein phosphatases and the lipid phosphatase PTEN. Myotubularin (hMTM1), the founder member, is mutated in myotubular myopathy, and a close homolog (hMTMR2) was recently found mutated in a recessive form of Charcot-Marie-Tooth neuropathy. Although myotubularin was thought to be a dual-specificity protein phosphatase, recent results indicate that it is primarily a lipid phosphatase, acting on phosphatidylinositol 3-monophosphate, and might be involved in the regulation of phosphatidylinositol 3-kinase (PI 3-kinase) pathway and membrane trafficking. The level and turnover of phosphoinositides (PIs) are tightly controlled by a large set of PI-specific enzymes (PI kinases and phosphatases). Mammalian PI phosphatases are conserved through evolution and among this large family the dual-specificity phosphatase (PTP/DSP) are metal-independent enzymes displaying the amino acid signature Cys-X5-Arg-Thr/Ser (CX5RT/S) in their active site. Such catalytic site characterizes the myotubularin 3-phosphatases that dephosphorylate PtdIns3P and PtdIns(3,5)P₂ and produce PtdIns5P. Substrates of myotubularins have been implicated in endocytosis and membrane trafficking while PtdIns5P may have a role in signal transduction. As a paradox, 6 of the 14 members of the myotubularin family lack enzymatic activity and are considered as dead phosphatases. Several myotubularins have been genetically linked to human diseases: MTM1 is mutated in the congenital myopathy X-linked centronuclear or myotubular myopathy (XLCNM) and MTMR14 (JUMPY) has been linked to an autosomal form of such disease, while MTMR2 and MTMR13 are mutated in Charcot-Marie-Tooth (CMT) neuropathies. Furthermore, recent evidences from genetic association studies revealed that several other myotubularins could be associated to chronic disorders such as cancer and obesity, highlighting their importance for human health. Here, we discuss cellular and physiological roles of myotubularins and their implication in human diseases, and we present potential pathological mechanisms affecting specific tissues in myotubularin-associated diseases. Myotubularins (MTMs) constitute a large family of lipid phosphatases that specifically dephosphorylate phosphatidylinositol (3)P. MTM1 and MTM2 are mutated in X-linked myotubular myopathy and Charcot-Marie-Tooth disease (type 4B), respectively, although the mechanisms whereby MTM dysfunction leads to these diseases is unknown. To gain insight into MTM function, we undertook the study of MTMs in the nematode Caenorhabditis elegans, which possesses representative homologues of the four major subgroups of MTMs identified in mammals. As in mammals, we found that C. elegans MTMs mediate distinct functions. let-512 (vps34) encodes the C. elegans homologue of the yeast and mammalian homologue of the phosphatidylinositol 3-kinase Vps34. We found that reduction of mtm-6 (F53A2.8) function by RNA inhibition rescued the larval lethality of let-512 (vps34) mutants and that the reduction of mtm-1 (Y110A7A.5) activity by RNA inhibition rescued the endocytosis defect of let-512 animals. Together, these observations provide genetic evidence that MTMs negatively regulate phosphatidylinositol (3)P levels. Analysis of MTM expression patterns using transcriptional green fluorescence protein reporters demonstrated that these two MTMs exhibit mostly non-overlapping expression patterns and that MTM-green fluorescence protein fusion proteins are localized to different subcellular locations. These observations suggest that some of the different functions of MTMs might, in part, be a consequence of unique expression and localization patterns. However, our finding that at least three C. elegans MTMs play essential roles in coelomocyte endocytosis, a process that also requires VPS34, indicates that MTMs do not simply turn off VPS34 but unexpectedly also function as positive regulators of biological processes. The myotubularins are a large family of lipid phosphatases with specificity towards PtdIns3P and PtdIns(3,5)P(2). Each of the 14 family members bears a signature phosphatase domain, which is inactive in six cases due to amino acid changes at the catalytic site. Fragmentary data have indicated heteromeric interactions between myotubularins, which have hitherto paired an active family member with an inactive one. In this study we have conducted a largescale analysis of potential associations within the human myotubularin family, through directed two-hybrid screening and immunoprecipitation of epitope-tagged proteins. We have confirmed all previously reported combinations and identified novel heteromeric interactions: MTMR8 with MTMR9, and MTMR3 with MTMR4, the first such combination of enzymatically active MTMs. We also report the capacity of several family members to self-associate, including MTMR3 and MTMR4. Subcellular localisation studies reveal a unique distribution of MTMR4 to endosomal structures, the major site of substrate lipid accumulation. All active MTMs we have tested (MTM1, MTMR2-MTMR4) reduce endosomal PtdIns3P levels upon overexpression. Despite this, only MTMR4 exerts any effect on EGF receptor trafficking and degradation, which is more pronounced with a phosphatase inactive form of MTMR4 and requires an intact FYVE domain. Phosphatidylinositol 3-phosphate [PtdIns(3)P] acts as a second messenger via the recruitment of diverse signalling proteins to various cellular compartments. Recent advances have highlighted the association of human diseases with mutations in phosphatases that regulate PtdIns(3)P levels. Myotubularin, the gene mutated in myotubular myopathy, functions as a lipid phosphatase with specificity for PtdIns(3)P. It is now apparent that there is an increasing family of proteins that are defined by their significant homology with myotubularin. The myotubularin-related gene family includes proteins that exhibit a lipid phosphatase catalytic motif, those that contain mutations of the critical catalytic residues, and at least one protein that functions as an adapter subunit for PtdIns(3)P-3-phosphatase activity. The present challenge is to understand how deregulation of phosphoinositide metabolism causes human disease. MTMR2 is a member of the myotubularin family of inositol lipid phosphatases, a large protein-tyrosine phosphatase subgroup that is conserved from yeast to humans. Furthermore, the peripheral neuromuscular disease Charcot-Marie Tooth disease type 4B has been attributed to mutations in the mtmr2 gene. Because the molecular mechanisms regulating MTMR2 have been poorly defined, we investigated whether reversible phosphorylation might regulate MTMR2 function. We used mass spectrometry-based methods to identify a high stoichiometry phosphorylation site on serine 58 of MTMR2. Phosphorylation at Ser(58), or a phosphomimetic S58E mutation, markedly decreased MTMR2 localization to endocytic vesicular structures. In contrast, a phosphorylation-deficient MTMR2 mutant (S58A) displayed constitutive localization to early endocytic structures. This localization pattern was accompanied by displacement of a PI(3)P-specific sensor protein and an increase in signal transduction pathways. Thus, MTMR2 phosphorylation is likely to be a critical mechanism by which MTMR2 access to its lipid substrate(s) is temporally and spatially regulated, thereby contributing to the control of downstream endosome maturation events. The Protein Tyrosine Phosphatase (PTP) family comprises a large and diverse group of enzymes, regulating a range of biological processes through de-phosphorylation of many proteins and lipids. These enzymes share a catalytic mechanism that requires a reduced and reactive cysteine nucleophile, making them potentially sensitive to inactivation and regulation by oxidation. Analysis of ten PTPs identified substantial differences in the sensitivity of these enzymes to oxidation in vitro. More detailed experiments confirmed the following rank order of sensitivity: PTEN and Sac1>PTPL1/FAP-1>>myotubularins. When the apparent sensitivity to oxidation of these PTPs in cells treated with hydrogen peroxide was analysed, this correlated well with the observed sensitivities to oxidation in vitro. These data suggested that different PTPs may fall into at least three different classes with respect to mechanisms of cellular redox regulation. 1. PTEN and Sac1 were readily and reversibly oxidised in vitro and in cells treated with hydrogen peroxide 2. PTPL1 appeared to be resistant to oxidation in cells, correlating with its sensitivity to reduction by glutathione in vitro 3. The myotubularin family of lipid phosphatases was almost completely resistant to oxidation in vitro and in cells. Our results show that sensitivity to reversible oxidation is not a necessary characteristic of the PTPs and imply that such sensitivity has evolved as a regulatory mechanism for some of this large family, but not others. Myotubularins, a large family of catalytically active and inactive proteins, belong to a unique subgroup of protein tyrosine phosphatases that use inositol phospholipids, rather than phosphoproteins, as physiological substrates. Here, by integrating crystallographic and deuterium-exchange mass spectrometry studies of human myotubularin-related protein-2 (MTMR2) in complex with phosphoinositides, we define the molecular basis for this unique substrate specificity. Phosphoinositide substrates bind in a pocket located on a positively charged face of the protein, suggesting an electrostatic mechanism for membrane targeting. A flexible, hydrophobic helix makes extensive interactions with the diacylglycerol moieties of substrates, explaining the specificity for membrane-bound phosphoinositides. An extensive H-bonding network and charge-charge interactions within the active site pocket determine phosphoinositide headgroup specificity. The conservation of these specificity determinants within the active, but not the inactive, myotubularins provides insight into the functional differences between the active and inactive members. Myotubularins (MTM) are a large subfamily of lipid phosphatases that specifically dephosphorylate at the D3 position of phosphatidylinositol 3-phosphate (PI(3)P) in PI(3)P and PI(3,5)P2. We recently found that MTMR6 specifically inhibits the Ca2+-activated K+ channel, KCa3.1, by dephosphorylating PI(3)P. We now show that inhibition is specific for MTMR6 and other MTMs do not inhibit KCa3.1. By replacing either or both of the coiled-coil (CC) and pleckstrin homology/GRAM (PH/G) domains of MTMs that failed to inhibit KCa3.1 with the CC and PH/G domains of MTMR6, we found that chimeric MTMs containing both the MTMR6 CC and PH/G domains functioned like MTMR6 to inhibit KCa3.1 channel activity, whereas chimeric MTMs containing either domain alone did not. Immunofluorescent microscopy demonstrated that both the MTMR6 CC and PH/G domains are required to co-localize MTMR6 to the plasma membrane with KCa3.1. These findings support a model in which two specific low affinity interactions are required to co-localize MTMR6 with KCa3.1: 1) between the CC domains on MTMR6 and KCa3.1 and (2) between the PH/G domain and a component of the plasma membrane. Our inability to detect significant interaction of the MTMR6 G/PH domain with phosphoinositides suggests that this domain may bind a protein. Identifying the specific binding partners of the CC and PH/G domains on other MTMs will provide important clues to the specific functions regulated by other MTMs as well as the mechanism(s) whereby loss of some MTMs lead to disease. Phosphoinositides control many different processes required for normal cellular function. Myotubularins are a family of Phosphatidylinositol 3-phosphate (PtdIns3P) phosphatases identified by the positional cloning of the MTM1 gene in patients suffering from X-linked myotubular myopathy and the MTMR2 gene in patients suffering from the demyelinating neuropathy Charcot-Marie-Tooth disease type 4B. MTM1 is a phosphatidylinositol phosphatase with reported specificity toward PtdIns3P, while the related proteins MTMR2 and MTMR3 hydrolyze both PtdIns3P and PtdIns(3,5)P2. We have investigated MTM1 and MTMR6 and find that they use PtdIns(3,5)P2 in addition to PtdIns3P as a substrate in vitro. The product of PtdIns(3,5)P2 hydrolysis, PtdIns5P, causes MTM1 to form a heptameric ring that is 12.5 nm in diameter, and it is a specific allosteric activator of MTM1, MTMR3, and MTMR6. A disease-causing mutation at arginine 69 of MTM1 falling within a putative pleckstrin homology domain reduces the ability of the enzyme to respond to PtdIns5P. We propose that the myotubularin family of enzymes utilize both PtdIns3P and PtdIns(3,5)P2 as substrates, and that PtdIns5P functions in a positive feedback loop controlling their activity. These findings highlight the importance of regulated phosphatase activity for the control of phosphoinositide metabolism. In eukaryotic cells, phosphatidylinositol is subject to differential phosphorylation, resulting in the production of seven distinct phosphatidylinositol phosphates, often referred to as phosphoinositides (PIs). PIs have numerous distinct roles in cellular regulation and membrane trafficking. Recently, myotubularin family PI 3-phosphatases have emerged as key regulators of phosphatidylinositol 3-phosphate and phosphatidylinositol 3,5-bisphosphate, two PIs that regulate traffic within the endosomal-lysosomal pathway. Mutations in several myotubularin genes lead to myotubular myopathy and Charcot-Marie-Tooth peripheral neuropathy. Strikingly, nearly half of the members of the human myotubularin family appear to be catalytically inactive. Several inactive myotubularins have essential functions in mammals. Recent work in mammalian cells and model organisms is shedding light on the roles of myotubularins in membrane traffic. |
336 | Can we detect DNA strand asymmetries using dinucleotide relative abundance "genomic signatures"? | The set of dinucleotide relative abundances can be regarded as a genomic signature because, despite diversity between species, it varies little between 50 kilobase or longer windows on a given genome. Thus, dinucleotide relative abundance profiles are species-type specific. These profiles are computed from the base step "odds ratios" that compare dinucleotide frequencies to those expected under the assumption of stochastic equilibrium (thorough shuffling). Dinucleotide relative abundance "genomic signatures" are strand-independent second-order DNA features. Thus, they cannot be used to detect DNA strand asymmetries. | [15046306, 10430918, 15716010, 9294192, 9520433, 12171605, 9190805, 18799480, 10066522, 7482779] | 443 | We provide data and analysis to support the hypothesis that the ancestor of animal mitochondria (Mt) and many primitive amitochondrial (a-Mt) eukaryotes was a fusion microbe composed of a Clostridium-like eubacterium and a Sulfolobus-like archaebacterium. The analysis is based on several observations: (i) The genome signatures (dinucleotide relative abundance values) of Clostridium and Sulfolobus are compatible (sufficiently similar) and each has significantly more similarity in genome signatures with animal Mt sequences than do all other available prokaryotes. That stable fusions may require compatibility in genome signatures is suggested by the compatibility of plasmids and hosts. (ii) The expanded energy metabolism of the fusion organism was strongly selective for cementing such a fusion. (iii) The molecular apparatus of endospore formation in Clostridium serves as raw material for the development of the nucleus and cytoplasm of the eukaryotic cell. Several bacterial genomes exhibit preference for G over C on the DNA leading strand extending from the origin of replication to the ter-region in the genomes of Escherichia coli, Mycoplasma genitalium, Bacillus subtilis, and marginally in Haemophilus influenzae, Mycoplasma pneumoniae, and Helicobacter pylori. Strand compositional asymmetry is not observed in the cyanobacterium Synechocystis sp. genome nor in the archaeal genomes of Methanococcus jannaschii, Methanobacterium thermoautotrophicum, and Archaeoglobus fulgidus. A strong strand compositional asymmetry is observed in beta-type but not alpha- or gamma-type human herpesviruses featuring G > C downstream of oriL and C > G upstream of oriL. Dinucleotide relative abundances (i.e., dinucleotide representations normalized by the component nucleotide frequencies) are consonant with respect to the leading and lagging strands. Strand compositional asymmetry may reflect on differences in replication synthesis of the leading versus lagging strand, on differences between template and coding strand associated with transcription-coupled repair mechanisms, on differences in gene density between the two strands, on differences in residue and codon biases in relation to gene function, expression level, or operon organization, or on differences in single or context-dependent base mutational rates. The absence of strand asymmetry in the archaeal genomes may reflect the presence of multiple origins of replication. We compare and contrast genome-wide compositional biases and distributions of short oligonucleotides across 15 diverse prokaryotes that have substantial genomic sequence collections. These include seven complete genomes (Escherichia coli, Haemophilus influenzae, Mycoplasma genitalium, Mycoplasma pneumoniae, Synechocystis sp. strain PCC6803, Methanococcus jannaschii, and Pyrobaculum aerophilum). A key observation concerns the constancy of the dinucleotide relative abundance profiles over multiple 50-kb disjoint contigs within the same genome. (The profile is rhoXY* = fXY*/fX*fY* for all XY, where fX* denotes the frequency of the nucleotide X and fY* denotes the frequency of the dinucleotide XY, both computed from the sequence concatenated with its inverted complementary sequence.) On the basis of this constancy, we refer to the collection [rhoXY*] as the genome signature. We establish that the differences between [rhoXY*] vectors of 50-kb sample contigs of different genomes virtually always exceed the differences between those of the same genomes. Various di- and tetranucleotide biases are identified. In particular, we find that the dinucleotide CpG=CG is underrepresented in many thermophiles (e.g., M. jannaschii, Sulfolobus sp., and M. thermoautotrophicum) but overrepresented in halobacteria. TA is broadly underrepresented in prokaryotes and eukaryotes, but normal counts appear in Sulfolobus and P. aerophilum sequences. More than for any other bacterial genome, palindromic tetranucleotides are underrepresented in H. influenzae. The M. jannaschii sequence is unprecedented in its extreme underrepresentation of CTAG tetranucleotides and in the anomalous distribution of CTAG sites around the genome. Comparative analysis of numbers of long tetranucleotide microsatellites distinguishes H. influenzae. Dinucleotide relative abundance differences between bacterial sequences are compared. For example, in these assessments of differences, the cyanobacteria Synechocystis, Synechococcus, and Anabaena do not form a coherent group and are as far from each other as general gram-negative sequences are from general gram-positive sequences. The difference of M. jannaschii from low-G+C gram-positive proteobacteria is one-half of the difference from gram-negative proteobacteria. Interpretations and hypotheses center on the role of the genome signature in highlighting similarities and dissimilarities across different classes of prokaryotic species, possible mechanisms underlying the genome signature, the form and level of genome compositional flux, the use of the genome signature as a chronometer of molecular phylogeny, and implications with respect to the three putative eubacterial, archaeal, and eukaryote domains of life and to the origin and early evolution of eukaryotes. Various methods have been developed to detect horizontal gene transfer in bacteria, based on anomalous nucleotide composition, assuming that compositional features undergo amelioration in the host genome. Evolutionary theory predicts the inevitability of false positives when essential sequences are strongly conserved. Foreign genes could become more detectable on the basis of their higher order compositions if such features ameliorate more rapidly and uniformly than lower order features. This possibility is tested by comparing the heterogeneities of bacterial genomes with respect to strand-independent first- and second-order features, (i) G + C content and (ii) dinucleotide relative abundance, in 1 kb segments. Although statistical analysis confirms that (ii) is less inhomogeneous than (i) in all 12 species examined, extreme anomalies with respect to (ii) in the Escherichia coli K12 genome are typically co-located with essential genes. Early biochemical experiments established that the set of dinucleotide odds ratios or 'general design' is a remarkably stable property of the DNA of an organism, which is essentially the same in protein-coding DNA, bulk genomic DNA, and in different renaturation rate and density gradient fractions of genomic DNA in many organisms. Analysis of currently available genomic sequence data has extended these earlier results, showing that the general designs of disjoint samples of a genome are substantially more similar to each other than to those of sequences from other organisms and that closely related organisms have similar general designs. From this perspective, the set of dinucleotide odds ratio (relative abundance) values constitute a signature of each DNA genome, which can discriminate between sequences from different organisms. Dinucleotide-odds ratio values appear to reflect not only the chemistry of dinucleotide stacking energies and base-step conformational preferences, but also the species-specific properties of DNA modification, replication and repair mechanisms. |
337 | What is the percentage of responders to tetrabenazine treatment for dystonia in children? | Tetrabenazine is used empirically in the treatment of dystonia in children with variable success. Observational studies report improvement of up to > 60% of the patients. | [18555882, 6889706, 9040721, 9549503, 3400500, 2904118, 22515742, 6128697, 12710012, 6502174, 19808991] | 444 | INTRODUCTION: Cerebral calcifications are a cause of secondary dystonia and may be an uncommon complication of radiotherapy. We report a very severe case of generalized dystonia due to postradiotherapy basal ganglia calcifications. CASE REPORT: An 8-year-old girl received 53 grays radiotherapy after surgery for craniopharyngioma. One year later she developed generalized dystonia. Computed tomography showed bilateral basal ganglia calcifications, especially of the lenticular nuclei. Pharmacological treatment with tetrabenazine, clonazepam and trihexiphenydile allowed a very limited improvement of dystonia; the course was complicated by dystonic storms and decompensations resulting from the iatrogenous panhypopituitarism. CONCLUSION: This case illustrates a severe complication of cranial irradiation which should be considered in the indications of this treatment, especially for children. Myoglobinuria may follow extreme muscular exertion or disorders that cause muscle necrosis. Dystonia has not been implicated previously. We studied an 8-year-old boy of non-Jewish, Mexican-American descent with autosomal-dominant dystonia musculorum deformans who developed rapidly progressive and severe generalized dystonia, hyperpyrexia, myoglobinuria, and renal failure. Curarization was required. Transient improvement was achieved with tetrabenazine and baclofen, but bilateral thalamotomy was then performed. Patients with severe dystonia should be observed for evidence of myoglobinuria. We retrospectively reviewed the clinical course and response to treatment of 67 patients with tardive dystonia. The age at onset ranged from 13 to 72 years without predilection to any particular age group or sex. Patients developed tardive dystonia even after relatively short duration of exposure to dopamine antagonists (21% within one year). Five of 42 patients withdrawn from these drugs remitted. Overall clinical improvement occurred in 52% of patients. Tetrabenazine and reserpine were most effective (greater than 50% response rate) in controlling dystonia. Anticholinergic drugs diminished dystonia in 46% of patients. Twenty-three children (aged less than 18 years) and 17 adults with severe widespread dystonia were treated with high doses of benzhexol (up to 130 mg daily introduced slowly over many weeks). Children tolerated higher doses (median 30 mg/day) than adults (median 20 mg/day). 52% of the children gained useful benefit, many (43%) without unwanted side effects. Such an approach was less successful in adults; 41% gained benefit, but only 35% had no side effects. Twelve adults with severe axial dystonia, and two children with life-threatening generalised dystonia were treated with a combination of a low constant dose of tetrabenazine to which were added pimozide and benzhexol as necessary. The dose of tetrabenazine was aimed at 75 mg daily; pimozide was increased (6 to 25 mg/day) until the dystonia was relieved or Parkinsonism and other side-effects prevented further increments; if necessary benzhexol (6 to 30 mg/day) then was added to control side-effects and to provide additional benefit. 75% of the adults with severe axial dystonia, and one of the two children with life threatening generalised dystonia gained useful benefit from this regime. It is concluded that high dose benzhexol is the present first treatment of choice for children with severe dystonia, and is worth a try in adults but with less expectation of success. When benzhexol treatment alone fails in adults with severe disabling axial dystonia, or in children with life-threatening generalised dystonia, combined therapy with tetrabenazine, pimozide and benzhexol may give valuable symptomatic relief. The authors report a patient with dystonia secondary to bilateral lesions of the basal ganglia, who improved dramatically with levodopa. The patient presented at the age of 4 years with progressive dystonia of the lower extremities and right upper extremity. Magnetic resonance imaging (MRI) of the brain showed bilateral hyperintensities of the globus pallidus that remained stable over the years. Despite extensive investigations, the etiology of her basal ganglia lesions remained nebulous. The patient's dystonia responded to Trihexyphenidyl and to tetrabenazine, but these medications needed to be stopped because of side effects. At the age of 12 years, small doses of levodopa-carbidopa were tried and resulted in dramatic improvement of her dystonia. The authors believe that in the pediatric population with secondary dystonias other than Segawa disease, even though this has been reported only rarely to be effective, a therapeutic trial with levodopa should be considered in some instances. |
338 | Is there any relationship between histone ubiquitylation and splicing? | Yes, in the case of histone H2B | [22188810, 19561118, 23209445, 23824326] | 445 | BACKGROUND: The packaging of DNA into chromatin regulates transcription from initiation through 3' end processing. One aspect of transcription in which chromatin plays a poorly understood role is the co-transcriptional splicing of pre-mRNA. RESULTS: Here we provide evidence that H2B monoubiquitylation (H2BK123ub1) marks introns in Saccharomyces cerevisiae. A genome-wide map of H2BK123ub1 in this organism reveals that this modification is enriched in coding regions and that its levels peak at the transcribed regions of two characteristic subgroups of genes. First, long genes are more likely to have higher levels of H2BK123ub1, correlating with the postulated role of this modification in preventing cryptic transcription initiation in ORFs. Second, genes that are highly transcribed also have high levels of H2BK123ub1, including the ribosomal protein genes, which comprise the majority of intron-containing genes in yeast. H2BK123ub1 is also a feature of introns in the yeast genome, and the disruption of this modification alters the intragenic distribution of H3 trimethylation on lysine 36 (H3K36me3), which functionally correlates with alternative RNA splicing in humans. In addition, the deletion of genes encoding the U2 snRNP subunits, Lea1 or Msl1, in combination with an htb-K123R mutation, leads to synthetic lethality. CONCLUSION: These data suggest that H2BK123ub1 facilitates cross talk between chromatin and pre-mRNA splicing by modulating the distribution of intronic and exonic histone modifications. Pre-messenger RNA splicing is carried out by a large ribonucleoprotein complex called the spliceosome. Despite the striking evolutionary conservation of the spliceosomal components and their functions, controversy persists about the relative importance of splicing in Saccharomyces cerevisiae-particularly given the paucity of intron-containing genes in yeast. Here we show that splicing of one pre-messenger RNA, SUS1, a component of the histone H2B ubiquitin protease machinery, is essential for establishing the proper modification state of chromatin. One protein complex that is intimately involved in pre-mRNA splicing, the yeast cap-binding complex, appears to be particularly important, as evidenced by its extensive and unique genetic interactions with enzymes that catalyze histone H2B ubiquitination. Microarray studies show that cap binding complex (CBC) deletion has a global effect on gene expression, and for approximately 20% of these genes, this effect is suppressed when ubiquitination of histone H2B is eliminated. Consistent with this finding of histone H2B dependent effects on gene expression, deletion of the yeast cap binding complex leads to overubiquitination of histone H2B. A key component of the ubiquitin-protease module of the SAGA complex, Sus1, is encoded by a gene that contains two introns and is misspliced when the CBC is deleted, leading to destabilization of the ubiquitin protease complex and defective modulation of cellular H2B levels. These data demonstrate that pre-mRNA splicing plays a critical role in histone H2B ubiquitination and that the CBC in particular helps to establish the proper state of chromatin and proper expression of genes that are regulated at the level of histone H2B ubiquitination. Eukaryotic gene expression involves tight coordination between transcription and pre-mRNA splicing; however, factors responsible for this coordination remain incompletely defined. Here, we explored the genetic, functional, and biochemical interactions of a likely coordinator, Npl3, an SR-like protein in Saccharomyces cerevisiae that we recently showed is required for efficient co-transcriptional recruitment of the splicing machinery. We surveyed the NPL3 genetic interaction space and observed a significant enrichment for genes involved in histone modification and chromatin remodeling. Specifically, we found that Npl3 genetically interacts with both Bre1, which mono-ubiquitinates histone H2B as part of the RAD6 Complex, and Ubp8, the de-ubiquitinase of the SAGA Complex. In support of these genetic data, we show that Bre1 physically interacts with Npl3 in an RNA-independent manner. Furthermore, using a genome-wide splicing microarray, we found that the known splicing defect of a strain lacking Npl3 is exacerbated by deletion of BRE1 or UBP8, a phenomenon phenocopied by a point mutation in H2B that abrogates ubiquitination. Intriguingly, even in the presence of wild-type NPL3, deletion of BRE1 exhibits a mild splicing defect and elicits a growth defect in combination with deletions of early and late splicing factors. Taken together, our data reveal a connection between Npl3 and an extensive array of chromatin factors and describe an unanticipated functional link between histone H2B ubiquitination and pre-mRNA splicing. |
339 | Which disease can be treated with Delamanid? | Delamanid is used in patients with multidrug-resistant tuberculosis. | [25327169, 25404020, 22670901, 26288734, 24729727] | 446 | INTRODUCTION: The limited availability of effective drugs causes difficulties in the management of multidrug-resistant tuberculosis (MDR-TB) and novel therapeutic agents are needed. Delamanid , a new nitro-hydro-imidazooxazole derivative, inhibits mycolic acid synthesis. This review covers the efficacy and safety of delamanid for MDR-TB. AREA COVERED: This paper reviews the pharmacological profile of delamanid and the results of clinical trials evaluating its efficacy for treating MDR-TB in combination with other anti-TB drugs. The drug's safety and tolerability profiles are also considered. EXPERT OPINION: Delamanid showed potent activity against drug-susceptible and -resistant Mycobacterium tuberculosis in both in vitro and in vivo studies. In clinical trials, the drug showed significant early bactericidal activity in pulmonary TB patients, and increased culture conversion after 2 months of treatment in combination with an optimized background regimen in MDR-TB patients. In addition, decreased mortality was observed in MDR-TB patients who received > 6 months of delamanid treatment. The drug was generally tolerable, but QT prolongation should be monitored carefully using electrocardiograms and potassium levels. Therefore, delamanid could be used as part of an appropriate combination regimen for pulmonary MDR-TB in adult patients when an effective treatment regimen cannot otherwise be composed for reasons of resistance or tolerability. Tuberculosis (Tb) continues to be a dreadful infection worldwide with nearly 1.5 million deaths in 2013. Furthermore multi/extensively drug-resistant Tb (MDR/XDR-Tb) worsens the condition. Recently approved anti-Tb drugs (bedaquiline and delamanid) have the potential to induce arrhythmia and are recommended in patients with MDR-Tb when other alternatives fail. The goal of elimination of Tb by 2050 will not be achieved without an effective new vaccine. The recent advancement in the development of Tb vaccines is the keen focus of this review. To date, Bacille Calmette Guerin (BCG) is the only licensed Tb vaccine in use, however its efficacy in pulmonary Tb is variable in adolescents and adults. There are nearly 15 vaccine candidates in various phases of clinical trials, includes five protein or adjuvant vaccines, four viral-vectored vaccines, three mycobacterial whole cell or extract vaccines, and one each of the recombinant live and the attenuated Mycobacterium tuberculosis (Mtb) vaccine. The advent of antibiotics for the treatment of tuberculosis (TB) represented a major breakthrough in the fight against the disease. However, since its first use, antibiotic therapy has been associated with the emergence of resistance to drugs. The incorrect use of anti-TB drugs, either due to prescription errors, low patient compliance, or poor quality of drugs, led to the widespread emergence of Mycobacterium tuberculosis strains with an expanding spectrum of resistance. The spread of multidrug-resistant (MDR) strains (ie, strains resistant to both isoniazid and rifampicin) has represented a major threat to TB control since the 1990s. In 2006, the first cases of MDR strains with further resistance to fluoroquinolone and injectable drugs were described and named extensively drug-resistant TB (XDR-TB). The emergence of XDR-TB strains is a result of mismanagement of MDR cases, and treatment relies on drugs that are less potent and more toxic than those used to treat drug-susceptible or MDR strains. Furthermore, treatment success is lower and mortality higher than achieved in MDR-TB cases, and the number of drugs necessary in the intensive phase of treatment may be higher than the four drugs recommended for MDR-TB. Linezolid may represent a valuable drug to treat cases of XDR-TB. Delamanid, bedaquiline, and PA-824 are new anti-TB agents in the development pipeline that have the potential to enhance the cure rate of XDR-TB. The best measures to prevent new cases of XDR-TB are the correct management of MDR-TB patients, early detection, and proper treatment of existing patients with XDR-TB. |
340 | What was the aim of the COSS (Carotid Occlusion Surgery Study) clinical trial? | The Carotid Occlusion Surgery Study (COSS) was conducted to determine if superficial temporal artery-middle cerebral artery (STA-MCA) bypass, when added to the best medical therapy, would reduce subsequent ipsilateral stroke in patients with complete internal carotid artery (ICA) occlusion and an elevated oxygen extraction fraction (OEF) in the cerebral hemisphere distal to the occlusion. | [23909253, 22645702, 21772967, 23101451, 22244016, 24339571, 22220280, 22682265, 21960571, 22068990] | 447 | OBJECT: The Carotid Occlusion Surgery Study (COSS) was a large, prospective clinical trial that examined whether superficial temporal artery-middle cerebral artery (STA-MCA) bypass, in addition to best medical therapy, reduced the risk of ipsilateral ischemic stroke in patients with carotid artery occlusion and hemodynamic cerebral ischemia. Despite improved cerebral hemodynamics and excellent bypass graft patency rates, COSS failed to show a benefit for the surgical group with respect to ipsilateral stroke recurrence at 2 years after treatment. This was due to a lower than expected rate of recurrent ipsilateral stroke in the medically treated group and a high rate of perioperative ipsilateral strokes in the surgical group. Critics of the trial have cited surgeon inexperience and technical difficulties related to the performance of the bypass graft as a leading cause of failure of the trial. METHODS: The authors retrospectively identified all patients from the COSS with an ipsilateral, perioperative (< 30 days) ischemic stroke after STA-MCA cortical branch anastomosis. Study records, operative notes, stroke adjudication forms, and imaging studies were reviewed. Ischemic strokes were characterized as bypass graft related or non-bypass graft related based on clinical and radiographic findings. RESULTS: Fourteen of 93 surgically treated patients experienced an ipsilateral, perioperative ischemic stroke. Postoperatively, the mean oxygen extraction fraction (OEF) ratio between the symptomatic and asymptomatic cerebral hemisphere significantly improved in these patients (1.30 ± 0.18 preoperative vs 1.12 ± 0.11 postoperative; p = 0.02), but did not normalize. In this cohort, total MCA occlusion time during the anastomosis (54.3 ± 23.5 minutes) was no different from the MCA occlusion time in those surgical patients who did not have a perioperative stroke (45.4 ± 24.2 minutes, p = 0.2). Bypass graft patency rates in patients with a perioperative stroke were 92% at 30 days (11 of 12 patients with patency data) and 83% at last follow-up visit (10 of 12 patients with patency data). These patency rates were not significantly different from those achieved at 30 days (100%; 76 of 76 patients with patency data; p = 0.14) and at last follow-up (99%; 71 of 72 patients with patency data; p = 0.052) in patients without a perioperative stroke. Eighty-six percent (12 of 14 patients) of strokes were likely attributable to factors unrelated to the STA-MCA anastomosis. Only 21% of strokes (3 of 14 patients) were in the territory of the recipient vessel and likely related to technical performance of the anastomosis itself. One patient was thought to have dual stroke mechanisms. CONCLUSIONS: Only a small minority of ipsilateral, perioperative ischemic strokes in the COSS could be attributed to technical problems of the bypass anastomosis. The majority of ischemic strokes could not be ascribed to this cause and were most likely due to patient hemodynamic fragility and the inability of patients to tolerate surgery. Intracranial atherosclerotic disease (ICAD) is the most common proximate mechanism of ischemic stroke worldwide. Approximately half of those affected are Asians. For diagnosis of ICAD, intra-arterial angiography is the gold standard to identify extent of stenosis. However, noninvasive techniques including transcranial ultrasound and MRA are now emerging as reliable modalities to exclude moderate to severe (50%-99%) stenosis. Little is known about measures for primary prevention of the disease. In terms of secondary prevention of stroke due to intracranial atherosclerotic stenosis, aspirin continues to be the preferred antiplatelet agent although clopidogrel along with aspirin has shown promise in the acute phase. Among Asians, cilostazol has shown a favorable effect on symptomatic stenosis and is of benefit in terms of fewer bleeds. Moreover, aggressive risk factor management alone and in combination with dual antiplatelets been shown to be most effective in this group of patients. Interventional trials on intracranial atherosclerotic stenosis have so far only been carried out among Caucasians and have not yielded consistent results. Since the Asian population is known to be preferentially effected, focused trials need to be performed to establish treatment modalities that are most effective in this population. OBJECT: The Carotid Occlusion Surgery Study (COSS) was conducted to determine if superficial temporal artery-middle cerebral artery (STA-MCA) bypass, when added to the best medical therapy, would reduce subsequent ipsilateral stroke in patients with complete internal carotid artery (ICA) occlusion and an elevated oxygen extraction fraction (OEF) in the cerebral hemisphere distal to the occlusion. A recent publication documented the methodology of the COSS in detail and briefly outlined the major findings of the trial. The surgical results of the COSS are described in detail in this report. METHODS: The COSS was a prospective, parallel-group, 1:1 randomized, open-label, blinded-adjudication treatment trial. Participants, who had angiographically demonstrated complete occlusion of the ICA causing either a transient ischemic attack or ischemic stroke within 120 days and hemodynamic cerebral ischemia indicated by an increased OEF measured by PET, were randomized to either surgical or medical treatment. One hundred ninety-five patients were randomized: 97 to the surgical group and 98 to the medical group. The surgical patients underwent an STA-MCA cortical branch anastomosis. RESULTS: In the intention-to-treat analysis, the 2-year rates for the primary end point were 21% for the surgical group and 22.7% for the medical group (p = 0.78, log-rank test). Fourteen (15%) of the 93 patients who had undergone an arterial bypass had a primary end point ipsilateral hemispheric stroke in the 30-day postoperative period, 12 within 2 days after surgery. The STA-MCA arterial bypass patency rate was 98% at the 30-day postoperative visit and 96% at the last follow-up examination. The STA-MCA arterial bypass markedly improved, although it did not normalize, the level of elevated OEF in the symptomatic cerebral hemisphere. Five surgically treated and 1 nonsurgically treated patients in the surgical group had a primary end point ipsilateral hemispheric stroke after the 30-day postoperative period. No baseline characteristics or intraoperative variables revealed those who would experience a procedure-related stroke. CONCLUSIONS: Despite excellent bypass graft patency and improved cerebral hemodynamics, STA-MCA anastomosis did not provide an overall benefit regarding ipsilateral 2-year stroke recurrence, mainly because of a much better than expected stroke recurrence rate (22.7%) in the medical group, but also because of a significant postoperative stroke rate (15%). Clinical trial registration no.: NCT00029146. Complete long segment carotid occlusion presents a treatment challenge. These patients cannot be managed adequately by endarterectomy or stenting. Despite best medical management, many continue to develop recurrent strokes. In this select group of patients, there may be role for flow augmentation techniques like superficial temporal-middle cerebral artery bypass. We report a patient who was thus successfully treated and remains asymptomatic. The relevant literature is reviewed. Intracranial atherosclerotic disease (ICAD) is a major cause of ischemic stroke worldwide and represents a significant health problem. The pathogenesis and natural history of ICAD are poorly understood, and rigorous treatment paradigms do not exist as they do for extracranial atherosclerosis. Currently, the best treatment for ICAD remains aspirin therapy, but many patients who are placed on aspirin continue to experience recurrent strokes. As microsurgical and endovascular techniques continue to evolve, the role of extracranial to intracranial bypass operations and stenting are increasingly being reconsidered. We performed a PubMed review of the English literature with a particular focus on treatment options for ICAD and present evidence-based data for the role of surgery and stenting in ICAD against medical therapy alone. BACKGROUND: Transcranial Doppler (TCD) CO2-reactivity and oxygen-15 positron emission tomography (PET) have both been used to measure the cerebral haemodynamic state in patients who may have a compromised blood flow. Our purpose was to investigate whether PET and TCD identify the same patients with an impaired flow state of the brain in patients with internal carotid artery (ICA) occlusion. METHODS: Patients with recent transient ischaemic attack or minor ischaemic stroke associated with ICA occlusion underwent TCD with measurement of CO2-reactivity and oxygen-15 PET within a median time interval of 6 days. RESULTS: We included 24 patients (mean age 64 ± 10 years). Seventeen (71%) patients had impaired CO2-reactivity (≤20%), of whom six had absent reactivity (0%) or steal (<0%) in the hemisphere ipsilateral to the ICA occlusion. PET of the perfusion state of the hemisphere ipsilateral to the ICA occlusion demonstrated stage 1 haemodynamic compromise (decreased cerebral blood flow (CBF) or increased cerebral blood volume (CBV) without increased oxygen extraction fraction (OEF)) in 13 patients and stage 2 (increased OEF) in 2 patients. In 12 patients (50%), there was agreement between TCD and PET, indicating haemodynamic compromise in 10 and a normal flow state of the brain in 2 patients. There was no significant correlation between CO2-reactivity and CBF ipsilateral/contralateral hemispheric ratio (r = 0.168, p value = 0.432), OEF ratio (r = -0.242, p value = 0.255), or CBV/CBF ratio (r = -0.368, p value = 0.077). CONCLUSIONS: In patients with symptomatic ICA occlusion, identification of an impaired flow state of the brain by PET and TCD CO2-reactivity shows concordance in only half of the patients. BACKGROUND AND PURPOSE: The Carotid Occlusion Surgery Study (COSS) was an improvement over the Extracranial-Intracranial Bypass Study, which did not utilize physiological selection. To assess possible reasons for early closure of the COSS trial, we reviewed COSS methods used to identify high-risk patients and compared results with separate quantitative data. METHODS: Increased oxygen extraction fraction (OEF) by positron emission tomography is a gold standard for ischemia, but the specific thresholds and equivalency of the semiquantitative OEF ratio utilized in COSS and quantitative OEF are at issue. RESULTS: The semiquantitative hemispheric OEF ratio used in COSS did not identify the same group of patients as did quantitative OEF using a threshold of 50%. CONCLUSIONS: The failure of COSS is likely caused by a failure of the semiquantitative, hemispheric OEF ratio method rather than by the selection for bypass based on hemodynamic compromise. Collaborators: Powers WJ, Grubb RL Jr, Videen TO, Derdeyn CP, Papps CH, McElvany K, Counts L, Kelly C, Barnard T, Ferrari J, Davis T, Hall T, Clarke WR Jr, Adams HP Jr, Costigan M, Singletary K, Fang Y, Marmet J, Ecklund D, Wichman M, Hansen M, Peters R, Anderson D, Woolson RF, Diltz C, Lang J, Beane L, Sieren J, Zhang Y, Videen TO, Hood JT Jr, Adams HP Jr, Weir BK, Brott T, Gorelick P, Ferguson G, Marler J, Ravina B, Galpern W, Moy C, Janis S, Haley EC, Grady S, Palesch Y, Eidelberg D, Derdeyn CP, Shinawi L, Hantler N, Tyler A, Catanzaro M, Fritsch S, Dacey R, Chicoine M, Zipfel G, Davis P, Olalde H, Rogers M, Jacobs P, Hitchon P, Leira E, Howard M, Hoballah J, Ireland J, Marshall R, Slane K, Connolly ES, Festa J, Solomon R, Dhamoon M, Wiley J, Linares G, Marchidann A, Szeder V, Noskin O, Antoniello D, Liberato B, Frontera J, Prabhakaran S, Chong J, Wright C, Zuccarello M, Koenig C, Sprafka L, Flaherty M, Kissela B, Kleindorfer D, Kempinsky-Cliver S, Broderick J, Roggee C, Kanter D, Woo D, Schneider A, Ewing I, Charbel F, Watson K, Mlinarevich N, Ruland S, Sepideh AH, Grysiewicz R, Jones J, Wilson J, Glazier S, Miller C, Jenkins W, Mintz A, Craig J, Tegeler C, O'Brien K, Ching M, Ionita C, Lee-Kwen P, Chan R, Munschauer F 3rd, Parkes K, Coad ML, Wrest K, Olson K, Harrington S, Hopkins LN, Grand W, Ferguson R, Heckler E, Pereira L, Sawyer R, Budny J, Levy E, Nemeth L, Ali J, Rasmussen P, Andrews-Hinders D, Katzan I, Uchino K, Mayberg M, Gupta R, Bartholomew J, Urbain JL, Wheeler T, Strozniak L, Krisht A, Partington S, Fewell D, Schmidley J, Steinberg G, Coburn M, Luu D, Wijman C, Darsaut T, Sinclair J, Guzman R, Ciaravino A, Varga M, Biederman K, Horner T, Payner T, Redelman K, Fleck J, Scott J, Barrow D, Holland E, Nahab F, Rahimazadeh K, Waddy S, Burke S, Chimowitz M, Frankel M, Samuels O, Sailor S, Braimah J, Stark C, Lane B, Lessard N, Howlett-Smith H, Ezzedine M, Stern B, Shipp B, Hanson K, Turan T, Osman N, Ivan C, Bruno A, Biller J, Lincoln FN, Guingrich S, Micheels A, Pritz M, Fleck J, Williams L, Jones W, Sears A, Faber K, Lopez A, Chadwick L, Matthews V, Girdler M, Lawton M, Hannegan L, Smith W, Dempsey R, Winne P, Washburn M, Li A, Sattin J, Jensen M, Chacon M, Dulli D, Newman G, Geraghty M, Page N, Kish J, Chan R, Hesser K, Lownie S, Hachinski V, Frank C, Fleming L, Baptista K, Matijevic S, Jovin T, Yonas H, Uchino K, Billigen J, Kirby L, Hammer M, Jumaa M, Lin R, Malik A, Ranawat N, Reddy V, Wechsler L, Zaidi S, Ranawat N, Rothfus MA, Adelson D, Gupta R, Tayal A, Gebel J, Nemoto E, Pindzola R, Mallory Y, Thompson BG, Auer D, Persad C, Powells D, Zahuranec D, Brown D, Hickenbottom S, Rosenwasser R, Simons E, Jensen M, Bell R, Kumar M, Moussouttas M, Pineda C, August D, Veznedaroglu E, Brock D, McGinnis G, Scollon R, Hilbert K, Johnson M, Unwin H, Graybeal D, Kopitnik T, Davis L, Blair A, Samson D, Lee J, Kassab M, Martin N, Saver J, Guzy J, Haines J, Varma J, Smith H, Fiaz R, Ali L, Carmichael ST, Liebeskind D, Ovbiagele B, Vespa P, Duke K, Starkman S, Froehler M, Tenser M, Villablanca P, Miller C, Shah S, Czernin J, Suzuki S, Dobkin B, Towfighi A, Kidwell C, Fredieu A, Tremwel M, Manglona D, Zabramski J, Snyder J, Frey J, Spetzler R, Flaster M, Mahmood MA, Akins P, Byer J, Schaefer J, Wentworth D, Croopnick S, Newman L, Cabe K, Hanson S, Castle A, Nussbaum E, Kuno L, Mattson J, Yonas H, Brown A, Malkoff M, Graham G, Stack E, Kirby L, Diaz F, Fessler R, Gordon V, Jacobs B, Ogilvy C, Buckley D, Mansala J, Bruce A, Buonanno F, Greer D, Whalen M, Meyer F, Fode-Thomas N, Thalacker S, Piepgras D, Fulgham J, Atkinson J, Biller J, Chadwick L, Anderson D, Schneck M, Dafer R, Vidal SM, Duckworth E, Selman W, Zalaski G, Cwiklinski V, Sila C, Tarr R, Bambakadis N, Suarez J, Graffagnino C, Stoner J, Moore S, Friedman A, Chilikuri V, Kesler J, Watridge C, Pannell M, Miller G, Jaciewicz M, Wright L, Newell D, Kraybill BM, Likosky W, French B, Bush J, Brown A, Block J, Blanchard B, Becker K, Sekhar L, Newell D, Tanzi P, Nuxoll D, Bybee H, Cramer S, Volpi J, Bautista M, Zhang J, Chiu D, Ling J, Bledsoe D, Tenorio J, Abdulrauf S, Kane M, Richard C, Swoboda M, Cruz-Flores S, Ibata B, Fessler R, Telck K, Gordon V, Pieper D, Silverman B, Diaz F, Whapham J, Hanson S, Castle A, Nussbaum E, Sherman D, Leonard A, Moreno L, Tonarelli S, Hart R, Carolin M, Roman G, Caron JL, Benevente O, Vollmer D, Sher A, Jett S, Neely G, Wallis RA, Panizzon K, Licht E, Cheng E, Gardner R, McAdoo J, Haupt D, Riggs-Ruupp K, Kassab M, Wehner S, Majid A, Slivka A, Agriesti J, Dobbs M, Fowler A, Pettigrew LC, Vaishnar A, Ryan S, Williams S, Nichols F, Close B, Bruno A, Switzer J, Hess D, Hall C, Rogalsky-Nacca J, Wilson S, Aucutt-Walter N, Huang D, Poole R, Ostrander M, Logan W, Schroer S, Friday G, Brown J, Derdeyn CP, Lich L, Schwarz S, Gaehle G, Mantil J, Strohmeyer P, Gagermeier E, Mattmuller S, Narayanan T, Shi B, Satter M, Simmons G, Christian B, Carone M, Perkins T, Brackney M, Mountz J, Price J, Sashin D, Meltzer C, Mathis C, Abella E, Cariddi D, Finley B, Valk P, Cronin J, Tesar R, Hichwa R, Sunderland J, Watkins L, Ponto L, Van Heertum R, Simpson N, Saxena C, Lockwood A, Haka M, Chugani H, Ferguson L, Musik O, Manger T, Reiman E, Intorcia D, Reeder S, Bandy D, Giurlani T, Prouty A, Burns C, Stone C, Christian B, Converse A, Roberts A, Oakes T, Dabbs K, Mullan B, Jacobson M, Kemp B, Brinkman T, Garg P, Morton K, Stroud P, Link K, Brown-Proctor C, Fahey F, Wollenweber S, Smith H, Fox P, Hardies J, Morena L, Narayana S, Jerabek P, Mazziotta J, Woods R, Fernandez O, Jaffer N, Brady T, Fischman A, Callahan R, Correi J, Goodman M, Crowe R, Votaw J, Bremner JD, Nye J, Eary J, Krohn K, Kauno K, Lewellen B, Kimura L, Shoner S, Lewellen T, Coleman RE, Petry N. |
341 | What are the advantages of the top down mass spectrometric analysis of histones? | Top down mass spectrometry is a way to analyze intact proteins thus enabling: isoform characteriztion and analysis of post-translational modifications. | [17652096, 14976258, 23466885, 21249157, 18302345, 17967882, 21898261, 23034525, 20848673, 15025441, 20707390, 20879039, 18381279, 17569892, 20486121, 20202861, 16457587, 16457588, 16457589, 22647927] | 448 | A global view of all core histones in yeast is provided by tandem mass spectrometry of intact histones H2A, H2B, H4, and H3. This allowed detailed characterization of >50 distinct histone forms and their semiquantitative assessment in the deletion mutants gcn5Delta, spt7Delta, ahc1Delta, and rtg2Delta, affecting the chromatin remodeling complexes SAGA, SLIK, and ADA. The "top down" mass spectrometry approach detected dramatic decreases in acetylation on H3 and H2B in gcn5Delta cells versus wild type. For H3 in wild type cells, tandem mass spectrometry revealed a direct correlation between increases of Lys(4) trimethylation and the 0, 1, 2, and 3 acetylation states of histone H3. The results show a wide swing from 10 to 80% Lys(4) trimethylation levels on those H3 tails harboring 0 or 3 acetylations, respectively. Reciprocity between these chromatin marks was apparent, since gcn5Delta cells showed a 30% decrease in trimethylation levels on Lys(4) in addition to a decrease of acetylation levels on H3 in bulk chromatin. Deletion of Set1, the Lys(4) methyltransferase, was associated with the linked disappearance of both Lys(4) methylation and Lys(14) and Lys(18) or Lys(23) acetylation on H3. In sum, we have defined the "basis set" of histone forms present in yeast chromatin using a current mass spectrometric approach that both quickly profiles global changes and directly probes the connectivity of modifications on the same histone. For more complete characterization of DNA-predicted proteins (including their posttranslational modifications) a "top-down" approach using high-resolution tandem MS is forwarded here by its application to methanogens in both hypothesis-driven and discovery modes, with the latter dependent on new automation benchmarks for intact proteins. With proteins isolated from ribosomes and whole-cell lysates of Methanococcus jannaschii (approximately 1,800 genes) using a 2D protein fractionation method, 72 gene products were identified and characterized with 100% sequence coverage via automated fragmentation of intact protein ions in a custom quadrupole/Fourier transform hybrid mass spectrometer. Three incorrect start sites and two modifications were found, with one of each determined for MJ0556, a 20-kDa protein with an unknown methylation at approximately 50% occupancy in stationary phase cells. The separation approach combined with the quadrupole/Fourier transform hybrid mass spectrometer allowed targeted and efficient comparison of histones from M. jannaschii, Methanosarcina acetivorans (largest Archaeal genome, 5.8 Mb), and yeast. This finding revealed a striking difference in the posttranslational regulation of DNA packaging in Eukarya vs. the Archaea. This study illustrates a significant evolutionary step for the MS tools available for characterization of WT proteins from complex proteomes without proteolysis. Chromatin is a highly structured nucleoprotein complex made of histone proteins and DNA that controls nearly all DNA-dependent processes. Chromatin plasticity is regulated by different associated proteins, post-translational modifications on histones (hPTMs) and DNA methylation, which act in a concerted manner to enforce a specific "chromatin landscape", with a regulatory effect on gene expression. Mass Spectrometry (MS) has emerged as a powerful analytical strategy to detect histone PTMs, revealing interplays between neighbouring PTMs and enabling screens for their readers in a comprehensive and quantitative fashion. Here we provide an overview of the recent achievements of state-of-the-art mass spectrometry-based proteomics for the detailed qualitative and quantitative characterization of histone post-translational modifications, histone variants, and global interactomes at specific chromatin regions. This synopsis emphasizes how the advances in high resolution MS, from "Bottom Up" to "Top Down" analysis, together with the uptake of quantitative proteomics methods by chromatin biologists, have made MS a well-established method in the epigenetics field, enabling the acquisition of original information, highly complementary to that offered by more conventional, antibody-based, assays. Recent technological advancements have allowed for highly-sophisticated mass spectrometry-based studies of the histone code, which predicts that combinations of post-translational modifications (PTMs) on histone proteins result in defined biological outcomes mediated by effector proteins that recognize such marks. While significant progress has been made in the identification and characterization of histone PTMs, a full appreciation of the complexity of the histone code will require a complete understanding of all the modifications that putatively contribute to it. Here, using the top-down mass spectrometry approach for identifying PTMs on full-length histones, we report that lysine 37 of histone H2B is dimethylated in the budding yeast Saccharomyces cerevisiae. By generating a modification-specific antibody and yeast strains that harbor mutations in the putative site of methylation, we provide evidence that this mark exist in vivo. Importantly, we show that this lysine residue is highly conserved through evolution, and provide evidence that this methylation event also occurs in higher eukaryotes. By identifying a novel site of histone methylation, this study adds to our overall understanding of the complex number of histone modifications that contribute to chromatin function. Recent advances in mass spectrometry instrumentation, such as FTICR and OrbiTrap, have made it possible to generate high-resolution spectra of entire proteins. While these methods offer new opportunities for performing "top-down" studies of proteins, the computational tools for analyzing top-down data are still scarce. In this paper we investigate the application of spectral alignment to the problem of identifying protein forms in top-down mass spectra (i.e., identifying the modifications, mutations, insertions, and deletions). We demonstrate how spectral alignment efficiently discovers protein forms even in the presence of numerous modifications and how the algorithm can be extended to discover positional isomers from spectra of mixtures of isobaric protein forms. Methylation of histone H4 at lysine 20 (K20) has been implicated in transcriptional activation, gene silencing, heterochromatin formation, mitosis, and DNA repair. However, little is known about how this modification is regulated or how it contributes to these diverse processes. Metabolic labeling and top-down mass spectrometry reveal that newly synthesized H4 is progressively methylated at K20 during the G(2), M, and G(1) phases of the cell cycle in a process that is largely inescapable and irreversible. Approximately 98% of new H4 becomes dimethylated within two to three cell cycles, and K20 methylation turnover in vivo is undetectable. New H4 is methylated regardless of prior acetylation, and acetylation occurs predominantly on K20-dimethylated H4, refuting the hypothesis that K20 methylation antagonizes H4 acetylation and represses transcription epigenetically. Despite suggestions that it is required for normal mitosis and cell cycle progression, K20 methylation proceeds normally during colchicine treatment. Moreover, delays in PR-Set7 synthesis and K20 methylation which accompany altered cell cycle progression during sodium butyrate treatment appear to be secondary to histone hyperacetylation or other effects of butyrate since depletion of PR-Set7 did not affect cell cycle progression. Together, our data provide an unbiased perspective of the regulation and function of K20 methylation. Mass spectrometry (MS) is rapidly becoming an indispensable tool for the analysis of posttranslational modifications (PTMs) of proteins, and particularly histone PTMs that regulate physiological processes. The more traditional bottom-up approach of searching for modifications on peptides rather than intact proteins (top-down) has proven useful for finding phosphorylation, acetylation, and ubiquitination sites. With the use of modern instrumentation and various MS-based techniques, peptides and their PTMs can be characterized in a high-throughput manner while still maintaining high sensitivity and specificity. In complement to bottom-up MS, recent advances in MS technology, such as high-field Fourier transform ion cyclotron resonance (FTICR)-mass spectrometry, have permitted the study of intact proteins and their modifications. On-line and off-line protein separation instruments coupled to FTICR-MS allow the characterization of PTMs previously undetectable with bottom-up approaches. The use of unique fragmentation techniques in FTICR-MS provides a viable option for the study of labile modifications. In this chapter, we provide a detailed description of the analytical tools - mass spectrometry in particular - that are used to characterize modifications on peptides and proteins. We also examine the applicability of these mass spectrometric techniques to the study of PTMs on histones via both the bottom-up and top-down proteomics approaches. Applying high-throughput Top-Down MS to an entire proteome requires a yet-to-be-established model for data processing. Since Top-Down is becoming possible on a large scale, we report our latest software pipeline dedicated to capturing the full value of intact protein data in automated fashion. For intact mass detection, we combine algorithms for processing MS1 data from both isotopically resolved (FT) and charge-state resolved (ion trap) LC-MS data, which are then linked to their fragment ions for database searching using ProSight. Automated determination of human keratin and tubulin isoforms is one result. Optimized for the intricacies of whole proteins, new software modules visualize proteome-scale data based on the LC retention time and intensity of intact masses and enable selective detection of PTMs to automatically screen for acetylation, phosphorylation, and methylation. Software functionality was demonstrated using comparative LC-MS data from yeast strains in addition to human cells undergoing chemical stress. We further these advances as a key aspect of realizing Top-Down MS on a proteomic scale. Eukaryotic histones serve as prototypical examples of posttranslational complexity with diverse modifications (PTMs) on many different residues that comprise a "Histone Code". To help crack this code more efficiently, we demonstrate a new strategy for protein characterization wherein complete PTM descriptions are obtained by database retrieval instead of manual interpretation of information-rich data from high-resolution tandem mass spectrometry (MS/MS). A database of nearly 50 000 modified histone H4 sequences was created and queried with 91 fragment ions from electron capture dissociation of a histone form +112 Da (versus unmodified mass) selectively accumulated in a quadrupole Fourier transform hybrid mass spectrometer. The correct form atop the retrieval list indicated dimethylation at Lys20, acetylation at the N terminus, and acetylation at Lys16 (resolved from trimethylation, Deltam = 0.036 Da). A statistical evaluation reveals the critical role of mass accuracy and that PTM "isomers" are retrieved as next-best matches. The applicability of shotgun annotation to forms of H4 with up to six PTMs is demonstrated, with extensibility to other histones (e.g., H2A, H2B, H3) and other protein classes projected. An online metal-free weak cation exchange-hydrophilic interaction LC/RPLC system has been developed for sensitive, high-throughput top-down MS. Here, we report results for analyzing PTMs of core histones, with a focus on histone H4, using this system. With just ∼24 μg on-column of core histones (H4, H2B, H2A, and H3) purified from human fibroblasts, 41 H4 isoforms were identified, with the type and location of PTMs unambiguously mapped for 20 of these variants. Compared to corresponding offline studies reported previously, the online weak cation exchange-hydrophilic interaction LC/RPLC platform offers significant improvement in sensitivity, with several orders of magnitude reduction in sample requirements and a reduction in the overall analysis time. To the best of our knowledge, this study represents the first online 2-D LC-MS/MS characterization of core histone mixture at the intact protein level. Quantitative proteomics has focused heavily on correlating protein abundances, ratios, and dynamics by developing methods that are protein expression-centric (e.g. isotope coded affinity tag, isobaric tag for relative and absolute quantification, etc.). These methods effectively detect changes in protein abundance but fail to provide a comprehensive perspective of the diversity of proteins such as histones, which are regulated by post-translational modifications. Here, we report the characterization of modified forms of HeLa cell histone H4 with a dynamic range >10(4) using a strictly Top Down mass spectrometric approach coupled with two dimensions of liquid chromatography. This enhanced dynamic range enabled the precise characterization and quantitation of 42 forms uniquely modified by combinations of methylation and acetylation, including those with trimethylated Lys-20, monomethylated Arg-3, and the novel dimethylated Arg-3 (each <1% of all H4 forms). Quantitative analyses revealed distinct trends in acetylation site occupancy depending on Lys-20 methylation state. Because both modifications are dynamically regulated through the cell cycle, we simultaneously investigated acetylation and methylation kinetics through three cell cycle phases and used these data to statistically assess the robustness of our quantitative analysis. This work represents the most comprehensive analysis of histone H4 forms present in human cells reported to date. Recent developments in top down mass spectrometry have enabled closely related histone variants and their modified forms to be identified and quantitated with unprecedented precision, facilitating efforts to better understand how histones contribute to the epigenetic regulation of gene transcription and other nuclear processes. It is therefore crucial that intact MS profiles accurately reflect the levels of variants and modified forms present in a given cell type or cell state for the full benefit of such efforts to be realized. Here we show that partial oxidation of Met and Cys residues in histone samples prepared by conventional methods, together with oxidation that can accrue during storage or during chip-based automated nanoflow electrospray ionization, confounds MS analysis by altering the intact MS profile as well as hindering posttranslational modification localization after MS/MS. We also describe an optimized performic acid oxidation procedure that circumvents these problems without catalyzing additional oxidations or altering the levels of posttranslational modifications common in histones. MS and MS/MS of HeLa cell core histones confirmed that Met and Cys were the only residues oxidized and that complete oxidation restored true intact abundance ratios and significantly enhanced MS/MS data quality. This allowed for the unequivocal detection, at the intact molecule level, of novel combinatorially modified forms of H4 that would have been missed otherwise. Oxidation also enhanced the separation of human core histones by reverse phase chromatography and decreased the levels of salt-adducted forms observed in ESI-FTMS. This method represents a simple and easily automated means for enhancing the accuracy and sensitivity of top down analyses of combinatorially modified forms of histones that may also be of benefit for top down or bottom up analyses of other proteins. Detailed characterization of the amino acid (aa) compositions of recombinant histone H3 (Xenopus laevis) and its Lys-9 mono-, di-, and trimethylated isoforms was carried out by ESI/FT-ICR-MS. The measured molecular masses of these four proteins did not agree with those predicted from the published wild-type histone H3 sequence. Using MS/MS with both collision-activated dissociation and electron capture dissociation, three aa substitutions (Gly102Ala, Cys110Ala, and Gly111Ala) were unambiguously identified in each protein by protein database searching and de novo peptide tag sequencing. In addition, it was determined through accurate mass measurement and elemental composition generation that Lys-9, to which the methyl groups are attached, is not in fact a lysine. Instead, it was identified as a chemical analog of lysine--aminoethylcysteine--in the methylated proteins. After incorporation of these three aa substitutions and the aminoethylcysteine into the protein sequences, the re-calculated molecular masses of four proteins were completely consistent with the measured values within 1 ppm. This work demonstrates the power of top-down MS for a detailed structural confirmation of recombinant proteins, even without prior information on aa substitutions or modifications. Transcriptional states are formed and maintained by the interaction and post-translational modification (PTM) of several chromatin proteins, such as histones and high mobility group (HMG) proteins. Among these, HMGA1a, a small heterochromatin-associated nuclear protein has been shown to be post-translationally modified, and some of these PTMs have been linked to apoptosis and cancer. In cancerous cells, HMGA1a PTMs differ between metastatic and nonmetastatic cells, suggesting the existence of an HMGA1a PTM code analogous to the "histone code." In this study, we expand on current knowledge by comprehensively characterizing PTMs on HMGA1a purified from human cells using both nanoflow liquid chromatography collision activated dissociation mediated Bottom Up and electron-transfer dissociation facilitated middle and Top Down mass spectrometry (MS). We find HMGA1a to be pervasively modified with many types of modifications such as methylation, acetylation, and phosphorylation, including finding novel sites. While Bottom Up MS identified lower level modification sites, Top and Middle Down MS were utilized to identify the most commonly occurring combinatorially modified forms. Remarkably, although we identify several individual modification sites through our Bottom Up and Middle Down MS analyses, we find relatively few combinatorially modified forms dominate the population through Top Down proteomics. The main combinatorial PTMs we find through the Top Down approach are N-terminal acetylation, Arg25 methylation along with phosphorylation of the three most C-terminal serine residues in primarily a diphosphorylated form. This report presents one of the most detailed analyses of HMGA1a to date and illustrates the strength of using a combined MS effort. The basis set of protein forms expressed by human cells from the H2B gene family was determined by Top Down Mass Spectrometry. Using Electron Capture Dissociation for MS/MS of H2B isoforms, direct evidence for the expression of unmodified H2B.Q, H2B.A, H2B.K/T, H2B.J, H2B.E, H2B.B, H2B.F, and monoacetylated H2B.A was obtained from asynchronous HeLa cells. H2B.A was the most abundant form, with the overall expression profile not changing significantly in cells arrested in mitosis by colchicine or during mid-S, mid-G2, G2/M, and mid-G1 phases of the cell cycle. Modest hyperacetylation of H2B family members was observed after sodium butyrate treatment. The modification of H3 in asynchronous HeLa cells was profiled using Top Down Mass Spectrometry. A broad distribution of species differing by 14 Da and containing less than 3% unmodified protein was observed for all three variants. Species of up to +168 Da were observed for H3.1, and fragmentation of all species by Electron Capture Dissociation (ECD) revealed approximately 5% methylation of K4 and approximately 50% dimethylation of K9. K14 and K23 were major sites of acetylation. H3.3 was slightly hypermodified with the apex of the distribution shifted by approximately +14 Da compared to H3.1. H3.1 (50% and 15%) from colchicine-treated cells was monophosphorylated and diphosphorylated, respectively, with equivalent modification of S10 and S28. Top Down analysis revealed that at least fourteen genes encoding histone H2A are coexpressed in HeLa cells. Characterization of these species revealed that all except H2A.Z and H2A.F/Z were alpha-N-acetylated, H2A.O and H2A.C,D,I,N,P were the most abundant, and those exceeding approximately 10% abundance lacked post-translational modifications. This unequivocal identification of H2A forms illustrates the advantages of Top Down Mass Spectrometry and provides a global perspective of H2A regulation through the cell cycle. |
342 | What is situs inversus? | Situs inversus totalis is a rare congenital anomaly with a complete mirror image of the thoracic and abdominal organs. | [25527777, 25884612, 26336554, 26043594, 26155468, 25296948, 26155517, 26087838] | 449 | INTRODUCTION: Situs inversus totalis (SIT) is an uncommon congenital syndrome, which refers to a reversal mirror-image of the normal thoracoabdominal organs position. The coexistence of SIT and abdominal aortic aneurysm has been seldom previously reported. PRESENTATION OF THE CASE: We report a case of a 69-year-old man with SIT and infrarenal abdominal aortic aneurysm (AAA) that underwent open repair with a straight graft through a minilaparatomy without evisceration. DISCUSSION: There is no consensus on which should be the optimum approach in cases of open surgical repair of AAA due to the limited number of cases described. The fact of intestinal scrolling to the left abdomen, unlike usual, is due to the anatomical arrangement of the root of the mesentery which is directed obliquely from duodenojejunal on the left side of the vertebra L2 to the ileocecal junction and right sacroiliac joint. CONCLUSION: A minilaparotomy without evisceration and with intestinal scrolling to left hemiabdomen, can be very useful and beneficial on those cases of congenital anatomical abnormalities that may add difficulty during the surgical procedure. INTRODUCTION: Situs inversus totalis (SIT) represents a total vertical transposition of the thoracic and abdominal organs which are arranged in a mirror image reversal of the normal positioning. We presented a successful pre-dialysis kidney transplantation from a living sibling donor with SIT and the longest donor follow-up period, along with analysis of the reviewed literature. CASE REPORT: The pair for pre-dialysis kidney transplantation included a 68-year-old mother and 34-year-old daughter at low immunological risk. Comorbid- ities evidenced in kidney donors with previously diagnosed SIT, included moderate arterial hypertension and borderline blood glucose level. Explantation of the left donor kidney and its placement into the right iliac fossa of the recipient were performed in the course of the surgical procedure. A month after nephrectomy, second degree renal failure was noticed in the donor. A 20-month follow-up of the donor's kidney and graft in the recipient proved that their functions were excellent. CONCLUSION: In donors with previously di- agnosed SIT the multidisciplinary approach, preoperative evaluation of the patient and detection of possible vascular anomalies are required to provide maximum safety for the donor. Agnathia, holoprosencephaly and situs inversus complex is an extremely rare form of congenital malformation. Though a few cases have been reported from other parts of the world, to the best of our knowledge none has been reported from India so far. Maternal alcoholism is regarded as an important factor causing holoprosencephaly. Disruption of the Shh gene signaling pathway is also said to be a factor for the occurrence of holoprosencephaly as well as left right asymmetry. Though several factors are suspected as a cause of this deformity, the precise aetiopathogenesis is still under debate. Lack of knowledge might be due to paucity of data from cases due to its rarity. Hereby, we are presenting a case of agnathia, holoprosencephaly and situs inversus born at 32 wk of gestation by an alcoholic mother. Externally the child had agnathia and cyclopia. There was no mandible or any oral cavity. It was accompanied by noticeable limb deformity. Internally there was holoprosencephaly, situs inversus totalis with several visceral abnormalities. To the best of our knowledge this is the first case of agnathia, holoprosencephaly and situs inversus complex to be reported in an indexed literature from India. This report also strengthens the association of maternal alcoholism with occurrence of holoprosencephaly. The authors reported a 73-year-old alcoholic man with previously-unrecognized situs inversus totalis suffering from left upper quadrant pain. Acute myocardial infarction was diagnosed and coronary angioplasty was performed immediately. However, the massive bleeding from the previously-unfound hepatomas caused hypovolemic shock and fatal outcome. Situs inversus totalis is a rare congenital anomaly with a complete mirror image of the thoracic and abdominal organs. Although being considered a benign entity, it would disturb diagnosis-making of the visceral diseases owing to the altered anatomy. To our knowledge, the coexistence of the coronary artery disease and ruptured hepatomas in situs inversus totalis, as in our patient, is never described. Recognition of any situs anomalies in time is the key to avoid misdiagnosis, inappropriate managements, and unwanted consequences. Situs inversus totalis is a rare congenital anomaly in which position of the heart and all abdominal viscera is reversed. Situs abnormalities usually go unnoticed but may be recognized by radiography or ultrasonography as an incidental finding or during evaluation for congenital heart diseases. We present such an extremely rare and to the best of our knowledge the third reported case of an injured spleen in the right hypochondrium, following seemingly trivial blunt trauma in a patient with situs inversus totalis who underwent splenectomy. The presence of associated congenital heart defects, visceral anatomical variations and mirror imaging makes the anaesthetic management as well as the surgical exercise a challenging one in such cases. BACKGROUND: Situs inversus totalis is a relatively rare condition and is an autosomal recessive congenital defect in which an abdominal and/or thoracic organ is positioned as a "mirror image" of the normal position in the sagittal plane. We report our experience of laparoscopic-assisted total gastrectomy with lymph node dissection performed for gastric cancer in a patient with situs inversus totalis. CASE PRESENTATION: A 58-year-old male was diagnosed with cT1bN0N0 gastric cancer. There were no vascular anomalies on abdominal angiographic computed tomography with three-dimensional reconstruction. laparoscopic-assisted total gastrectomy was performed with D1+ lymph node dissection, in accordance with the Japanese Gastric Cancer Treatment Guidelines. There were no intraoperative issues, and no postoperative complications. CONCLUSIONS: This was the first report describing laparoscopic-assisted total gastrectomy with the standard typical lymph node dissection in the English literature. We emphasize that the position of trocars and the standing side of the primary surgeon during the lymph node dissection are critical. |
343 | Can SUMO affect calcium homeostasis? | Yes, SUMO proteins can affect calcium homeostasis. | [10995744, 24290762, 23510938, 21900893] | 450 | The rapid, activity-dependent quantal presynaptic release of neurotransmitter is vital for brain function. The complex process of vesicle priming, fusion, and retrieval is very precisely controlled and requires the spatiotemporal coordination of multiple protein-protein interactions. Here, we show that posttranslational modification of the active zone protein Rab3-interacting molecule 1α (RIM1α) by the small ubiquitin-like modifier 1 (SUMO-1) functions as a molecular switch to direct these interactions and is essential for fast synaptic vesicle exocytosis. RIM1α SUMOylation at lysine residue K502 facilitates the clustering of CaV2.1 calcium channels and enhances the Ca(2+) influx necessary for vesicular release, whereas non-SUMOylated RIM1α participates in the docking/priming of synaptic vesicles and maintenance of active zone structure. These results demonstrate that SUMOylation of RIM1α is a key determinant of rapid, synchronous neurotransmitter release, and the SUMO-mediated "switching" of RIM1α between binding proteins provides insight into the mechanisms underpinning synaptic function and dysfunction. The axon/dendrite specification collapsin response mediator protein 2 (CRMP2) bidirectionally modulates N-type voltage-gated Ca ( 2+) channels (CaV2.2). Here we demonstrate that small ubiquitin-like modifier (SUMO) protein modifies CRMP2 via the SUMO E2-conjugating enzyme Ubc9 in vivo. Removal of a SUMO conjugation site KMD in CRMP2 (K374A/M375A/D376A; CRMP2AAA) resulted in loss of SUMOylated CRMP2 without compromising neurite branching, a canonical hallmark of CRMP2 function. Increasing SUMOylation levels correlated inversely with calcium influx in sensory neurons. CRMP2 deSUMOylation by SUMO proteases SENP1 and SENP2 normalized calcium influx to those in the CRMP2AAA mutant. Thus, our results identify a novel role for SUMO modification in CRMP2/CaV2.2 signaling pathway. The calcium-transporting ATPase ATP2A2, also known as SERCA2a, is a critical ATPase responsible for Ca(2+) re-uptake during excitation-contraction coupling. Impaired Ca(2+) uptake resulting from decreased expression and reduced activity of SERCA2a is a hallmark of heart failure. Accordingly, restoration of SERCA2a expression by gene transfer has proved to be effective in improving cardiac function in heart-failure patients, as well as in animal models. The small ubiquitin-related modifier (SUMO) can be conjugated to lysine residues of target proteins, and is involved in many cellular processes. Here we show that SERCA2a is SUMOylated at lysines 480 and 585 and that this SUMOylation is essential for preserving SERCA2a ATPase activity and stability in mouse and human cells. The levels of SUMO1 and the SUMOylation of SERCA2a itself were greatly reduced in failing hearts. SUMO1 restitution by adeno-associated-virus-mediated gene delivery maintained the protein abundance of SERCA2a and markedly improved cardiac function in mice with heart failure. This effect was comparable to SERCA2A gene delivery. Moreover, SUMO1 overexpression in isolated cardiomyocytes augmented contractility and accelerated Ca(2+) decay. Transgene-mediated SUMO1 overexpression rescued cardiac dysfunction induced by pressure overload concomitantly with increased SERCA2a function. By contrast, downregulation of SUMO1 using small hairpin RNA (shRNA) accelerated pressure-overload-induced deterioration of cardiac function and was accompanied by decreased SERCA2a function. However, knockdown of SERCA2a resulted in severe contractile dysfunction both in vitro and in vivo, which was not rescued by overexpression of SUMO1. Taken together, our data show that SUMOylation is a critical post-translational modification that regulates SERCA2a function, and provide a platform for the design of novel therapeutic strategies for heart failure. |
344 | What is the indication of Daonil (Glibenclamide)? | Glibenclamide is an antidiabetic and antiglycemic, used in severe NIDDM, and increasingly viewed as a rational alternative to insulin therapy. | [22639778, 10199151, 6805141, 21608438, 12460666, 16922811] | 451 | We have investigated the presence of diazoxide- and nicorandil-activated K+ channels in rat skeletal muscle. Activation of potassium transport in the rat skeletal muscle myoblast cell line L6 caused a stimulation of cellular oxygen consumption, implying a mitochondrial effect. Working with isolated rat skeletal muscle mitochondria, both potassium channel openers (KCOs) stimulate respiration, depolarize the mitochondrial inner membrane and lead to oxidation of the mitochondrial NAD-system in a strict potassium-dependent manner. This is a strong indication for KCO-mediated stimulation of potassium transport at the mitochondrial inner membrane. Moreover, the potassium-specific effects of both diazoxide and nicorandil on oxidative phosphorylation in skeletal muscle mitochondria were completely abolished by the antidiabetic sulfonylurea derivative glibenclamide, a well-known inhibitor of ATP-regulated potassium channels (K(ATP) channels). Since both diazoxide and nicorandil facilitated swelling of de-energised mitochondria in KSCN buffer at the same concentrations, our results implicate the presence of a mitochondrial ATP-regulated potassium channel (mitoK(ATP) channel) in rat skeletal muscle which can modulate mitochondrial oxidative phosphorylation. 1. The hypoglycaemic effect of fermented seeds of Parkia biglobosa (PB; African locust bean), a natural nutritional condiment that features frequently in some African diets as a spice, was investigated in the present study in alloxan-induced diabetic rats. Its effect was compared with that of glibenclamide (Daonil; Sanofi-Aventis, Paris, France), a reference antidiabetic drug. The effects of PB on lipid profiles were also examined. 2. In order to assess the hypoglycaemic and hypolipidaemic effects of aqueous and methanolic extracts of PB on experimental animals, fasting plasma glucose (FPG), total cholesterol, triglyceride, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) were determined. In addition, the weight of each animal was determined to assess any possible weight gain or loss in the experimental animals (diabetic rats treated with Daonil (group C), the aqueous extract of PB (group D) or the methanolic extract of PB (group E)) compared with control groups (non-diabetic (group A) and non-treated diabetic (group B)). 3. A single dose of 120 mg/kg, i.v., alloxan administered to rats resulted in significant increases in the FPG (P < 0.001) of test animals compared with controls. However, dietary supplementation with PB (6 g/kg extract for 4 weeks administered orally using an intragastric tube) ameliorated the alloxan-induced diabetes in a manner comparable with that of the reference antidiabetic drug glibenclamide. Aqueous and methanolic extracts of PB (6% w/w) elicited 69.2% and 64.4% reductions, respectively, in FPG compared with 70.4% in 0.01 mg/150 g glibenclamide-treated rats. 4. Although animals treated with the aqueous extract of PB gained weight in manner similar to normal controls, animals given the methanolic extract and glibenclamide lost weight in manner similar to non-treated diabetic rats. In addition, high levels of HDL and low LDL were observed in animals treated with the aqueous extract of PB, a pattern similar to that seen in normal controls. Low levels of HDL and high levels of LDL were observed in animals treated with the methanolic extract of PB, a pattern similar to that seen in non-treated diabetic controls. 5. The results of the present study demonstrate that both aqueous and methanolic extracts of fermented seeds of PB exert a hypoglycaemic effect; hence, PB has an antidiabetic property. However, only the aqueous extract of PB ameliorated the loss of bodyweight usually associated with diabetes. Although the aqueous extract has a favourable lipid profile, which is probably an indication of its possible anti-arteriogenic property (hypertension and ischaemic heart diseases being common complications in diabetes mellitus), the methanolic extract shows possible contraindication to ischaemic heart diseases. |
345 | Which is the most typical peptide sequence responsible for retrieval of endoplasmic reticulum (ER) lumenal proteins from the Golgi apparatus? | The lumenal endoplasmic reticulum (ER) proteins carry a specific sorting signal which enables their retrieval from multiple post-ER compartments (up to the TGN along the exocytotic pathway), back to the ER. The most typical such signal is the carboxyl-terminal Lys-Asp-Glu-Leu (KDEL), which is bound by a KDEL receptor in the Golgi apparatus, as well as in the intermediate compartment. Thus KDEL functions as a retrieval signal of lumenal ER proteins from Golgi to ER. | [7798312, 9118249, 9914159, 15170512, 9442098, 8385108, 1334264, 10748089] | 452 | The carboxyl-terminal Lys-Asp-Glu-Leu (KDEL), or a closely-related sequence, is important for ER localization of both lumenal as well as type II membrane proteins. This sequence functions as a retrieval signal at post-ER compartment(s), but the exact compartment(s) where the retrieval occurs remains unresolved. With an affinity-purified antibody against the carboxyl-terminal sequence of the mammalian KDEL receptor, we have investigated its subcellular localization using immunogold labeling on thawed cryosections of different tissues, such as mouse spermatids and rat pancreas, as well as HeLa, Vero, NRK, and mouse L cells. We show that rab1 is an excellent marker of the intermediate compartment, and we use this marker, as well as budding profiles of the mouse hepatitis virus (MHV) in cells infected with this virus, to identify this compartment. Our results demonstrate that the KDEL receptor is concentrated in the intermediate compartment, as well as in the Golgi stack. Lower but significant labeling was detected in the rough ER. In general, only small amounts of the receptor were detected on the trans side of the Golgi stack, including the trans-Golgi network (TGN) of normal cells and tissues. However, some stress conditions, such as infection with vaccinia virus or vesicular stomatitis virus, as well as 20 degrees C or 43 degrees C treatment, resulted in a significant shift of the distribution towards the trans-TGN side of the Golgi stack. This shift could be quantified in HeLa cells stably expressing a TGN marker. No significant labeling was detected in structures distal to the TGN under all conditions tested. After GTP gamma S treatment of permeabilized cells, the receptor was detected in the beta-COP-containing buds/vesicles that accumulate after this treatment, suggesting that these vesicles may transport the receptor between compartments. We propose that retrieval of KDEL-containing proteins occurs at multiple post-ER compartments up to the TGN along the exocytotic pathway, and that within this pathway, the amounts of the receptor in different compartments varies according to physiological conditions. The secretory pathway of eukaryotic cells consists of a number of distinct membrane-bound compartments interconnected by vesicular traffic. Each compartment has a characteristic content of proteins and lipids, which must be maintained. This is achieved in most cases by active sorting-proteins may reach the wrong compartment but are continually retrieved. A good example is the retrieval system for lumenal ER proteins. These proteins carry a specific sorting signal, typically the tetrapeptide KDEL, which is bound by a receptor in the Golgi apparatus. The receptor-ligand complex, together with escaped ER membrane proteins, returns to the ER. Many of the components of vesicle traffic, including the coat proteins required for vesicle budding from the ER, those that form retrograde vesicles on post-ER compartments, and integral membrane proteins that target the vesicles to their correct destination, have been identified. The sorting events that occur can largely be understood in terms of specific protein-protein interactions involving these components. However, sorting of some membrane proteins, including the vesicle targeting molecules, is influenced by their transmembrane domains, and it is likely that segregation of these is dependent on the composition and biophysical properties of the lipid bilayer, which very between compartments. The secretory pathway is thus a dynamic entity, split into discrete organelles by the constant segregation and recycling of lipids and proteins, processes that are ultimately driven by the mechanics of vesicle formation and fusion. To investigate the role of the KDEL receptor in the retrieval of protein toxins to the mammalian cell endoplasmic reticulum (ER), lysozyme variants containing AARL or KDEL C-terminal tags, or the human KDEL receptor, have been expressed in toxin-treated COS 7 and HeLa cells. Expression of the lysozyme variants and the KDEL receptor was confirmed by immunofluorescence. When such cells were challenged with diphtheria toxin (DT) or Escherichia coli Shiga-like toxin 1 (SLT-1), there was no observable difference in their sensitivities as compared to cells which did not express these exogenous proteins. By contrast, the cytotoxicity of Pseudomonas exotoxin A (PE) is reduced by expressing lysozyme-KDEL, which causes a redistribution of the KDEL receptor from the Golgi complex to the ER, and cells are sensitised to this toxin when they express additional KDEL receptors. These data suggest that, in contrast to SLT-1, PE can exploit the KDEL receptor in order to reach the ER lumen where it is believed that membrane transfer to the cytosol occurs. This contention was confirmed by microinjecting into Vero cells antibodies raised against the cytoplasmically exposed tail of the KDEL receptor. Immunofluorescence confirmed that these antibodies prevented the retrograde transport of the KDEL receptor from the Golgi complex to the ER, and this in turn reduced the cytotoxicity of PE, but not that of SLT-1, to these cells. Retention of soluble proteins in the endoplasmic reticulum is dependent on their interaction with the KDEL (Lys-Asp-Glu-Leu) receptor in the Golgi apparatus and their subsequent retrieval back to the endoplasmic reticulum. We have studied the three-dimensional organization of the human KDEL receptor using site-directed mutagenesis and sulfhydryl-specific labeling. We have identified four amino acid residues, Arg-5, Asp-50, Tyr-162, and Asn-165, which we suggest participate in the formation of the ligand binding pocket. Arg-5 and Asp-50 are shown to be located on the lumenal side of the membrane and are inaccessible from the cytoplasm. In addition, our results strongly support a topology of the KDEL receptor similar to the family of G-protein-coupled receptors with seven transmembrane domains. Furthermore, Asp-50 plays a crucial role in the binding of His/Lys-Asp-Glu-Leu ligands, but is not required for Asp-Asp-Glu-Leu binding, suggesting that this residue forms an ion pair with the positively charged amino acid residue positioned 4 residues from the carboxyl terminus of the ligand. In eukaryotic cells, protein secretion provides a complex organizational problem. Secretory proteins are first transported, in an unfolded state, across the membrane of the endoplasmic reticulum (ER), and are then carried in small vesicles to the Golgi apparatus and finally to the cell membrane. The ER contains soluble proteins which catalyse the folding of newly synthesized polypeptides. These proteins are sorted from secretory proteins in the Golgi complex: they carry a sorting signal (the tetrapeptide KDEL or a related sequence) that allows them to be selectively retrieved and returned to the ER. This retrieval process also appears to be used by some bacterial toxins to aid their invasion of the cell: these toxins contain KDEL-like sequences and may, in effect, follow the secretory pathway in reverse. The membrane-bound receptor responsible for sorting luminal ER proteins has been identified in yeast by genetic means, and related receptors are found in mammalian cells. Unexpectedly, this receptor has a second role: in yeast it is required to maintain the normal size and function of the Golgi apparatus. By helping to maintain the composition of both ER and Golgi compartments, the KDEL receptor has an important role in the organization of the secretory pathway. Hydroxylation of lysyl residues is crucial for the unique glycosylation pattern found in collagens and for the mechanical strength of fully assembled extracellular collagen fibers. Hydroxylation is catalyzed in the lumen of the endoplasmic reticulum (ER) by a specific enzyme, lysyl hydroxylase (LH). The absence of the known ER-specific retrieval motifs in its primary structure and its association with the ER membranes in vivo have suggested that the enzyme is localized in the ER via a novel retention/retrieval mechanism. We have identified here a 40-amino acid C-terminal peptide segment of LH that is able to convert cathepsin D, normally a soluble lysosomal protease, into a membrane-associated protein. The same segment also markedly slows down the transport of the reporter protein from the ER into post-ER compartments, as assessed by our pulse-chase experiments. The retardation efficiency mediated by this C-terminal peptide segment is comparable with that of the intact LH but lower than that of the KDEL receptor-based retrieval mechanism. Within this 40-amino acid segment, the first 25 amino acids appear to be the most crucial ones in terms of membrane association and ER localization, because the last 15 C-terminal amino acids did not possess substantial retardation activity alone. Our findings thus define a short peptide segment very close to the extreme C terminus of LH as the only necessary determinant both for its membrane association and localization in the ER. |
346 | What are the clinical trial outcomes of metformin use in polycystic ovary disease? | Metformin treatment vs placebo significantly but modestly improves ovulation frequency in women with abnormal ovarian function/oligomenorrhea and polycystic ovaries, the lower BMI women were more likely to become pregnant. While in naturally conceiving normal weight PCOS women pre-treatment with metformin tends to improve pregnancy rates, pre-treatment with metformin prior to conventional IVF/ICSI in women with PCOS does not improve stimulation or clinical outcome.
Metformin is an effective addition to Clomifene Citrate in term of reestablishment of ovulation and full-term pregnancies achievement.
Studies on the effect of metformin on serum Anti-Mullerian Hormone levels /AMH concentrations bring conflicting results, from Metformin having no effect on AMH to Metformin treatment resulting in significant decrease of AMH levels, antral follicle numbers and ovarian volume.
Metformin has been shown to cause significant weight loss (and leptin reduction) in PCOS. | [11473953, 20517830, 15117902, 15802325, 21631446, 23412023, 12364442, 19342396, 11836287] | 453 | BACKGROUND: Metformin, an insulin-sensitizing agent, has been used successfully as the first-line drug to induce ovulation in women with polycystic ovary syndrome. There are, however, very few studies evaluating metformin treatment in women with clomiphene citrate (CC)-resistant polycystic ovaries (PCO). METHODS: Twenty infertile Chinese women aged <40 years, who had ultrasound features of PCO and remained anovulatory on CC, were randomized by computer using the sealed envelope method to receive placebo or metformin 500 mg three times a day for 3 months. Hormonal and metabolic profiles were determined before the therapy and were repeated after 3 months for women who failed to become pregnant within this period. Clomiphene was then added for one cycle to those women who did not ovulate after taking placebo or metformin alone. RESULTS: The median ovulation rate in the placebo group was 0% (range: 0--50%) after placebo only and 6.9% (range: 0--50%) after placebo and CC, whereas the corresponding rates in the metformin group were 0% (range: 0--22%) and 0% (range: 0--22%) respectively. There was no improvement in the ovulation rate despite a significant reduction of body mass index, serum testosterone and fasting leptin concentrations in the metformin group. CONCLUSIONS: Metformin treatment may result in successful ovulation only in certain subgroups of these women. BACKGROUND: Polycystic ovarian syndrome (PCOS) is the most common hormonal dysfunction in women. It's a cause of female infertility by oligoanovulation, clinical and biochemical hyperandrogenism and polycystic ovaries. Weight loss, firstly proposed in overweight or obese patient suffering from PCOS, aims to reduce hyperinsulinism and hyperandrogenism. Recently, Metformin, an insulin sensitizer, has been proposed as an alternative first line treatment for polycystic ovarian syndrome by improving hyperinsulinemia and hyperandrogenism in these women. AIM: The aim of our study, and through a literature review, is to demonstrate if Metformin should be used as a first-line drug for infertile women with this syndrome or as an adjunction to Clomifene Citrate, the longest established treatment already used in this syndrome. METHODS: A prospective comparative study including 63 patients with PCOS has been done during 2 years. Women were randomly allocated to clomifene + Metformin (Metformin group, Metformin took during 8 weeks, 850 mg twice a day, plus Clomifene 100 mg per day during five days) or Clomifene only (100 mg per day during five days). All patients underwent a two- month's diet. RESULTS: The middle age was about 30.63 years and the body mass index (BMI) was about 29.88 kg/ m(2). We noticed a 6.2% weight loss in both groups (a non significant difference in p=0.04). The median of infertility period was about 2.49 years. The ovulation rate in the Metformin group was 53.12% (significant difference for inducing ovulation p=0.02) and 32.25% in Clomifene group (non-significant difference 0.07). There was also a significant difference for ongoing pregnancies (p=0.04). In fact, 11 on 32 patients (34%) achieved a full-term pregnancy in Metformin group versus only 4 ones on 31 patients (12.9%) in Clomifene group. CONCLUSION: Our conclusion is that Metformin is an effective addition to Clomifene Citrate in term of reestablishment of ovulation and full-term pregnancies achievement, excluding ART cycles. BACKGROUND: Our aim was to investigate the effect of pre-treatment with metformin in women with polycystic ovary syndrome (PCOS) scheduled for IVF stimulation. METHODS: Seventy-three oligo/amenorrhoeic women with polycystic ovaries and at least one of the following criteria: hyperandrogenaemia, elevated LH/FSH ratio, hyperinsulinism, decreased SHBG levels or hirsutism, were studied. Normal weight and overweight patients were randomized separately in a prospective, randomized, double blind study. All patients were treated for at least 16 weeks with metformin (1000 mg bid) or placebo ending on the day of HCG injection. RESULTS: No differences were found in the primary end-points: duration of FSH stimulation 14.4 (13.1-15.7) versus 14.2 (12.6-15.7) days or estradiol on the day of HCG injection 6.8 (5.3-8.2) versus 7.6 (5.6-9.6) nmol/l in the metformin and placebo groups, respectively. The secondary end-points number of oocytes, fertilization rates, embryo quality, pregnancy rates and clinical pregnancy rates were equal. However, in the normal weight subgroup (BMI <28 kg/m(2), n = 27), pregnancy rates following IVF were 0.71 (0.63-0.79) versus 0.23 (0.15-0.31) in the metformin and placebo groups, respectively (P = 0.04). Overall clinical pregnancy rates were equal: 0.51 (0.34-0.68) versus 0.44 (0.27-0.62) in the metformin and placebo groups, respectively. However, in the normal weight subgroup, clinical pregnancy rates were 0.67 (0.43-0.91) and 0.33 (0.06-0.60), respectively (P = 0.06). CONCLUSIONS: Pre-treatment with metformin prior to conventional IVF/ICSI in women with PCOS does not improve stimulation or clinical outcome. However, among normal weight PCOS women, pre-treatment with metformin tends to improve pregnancy rates. Further studies in subgroups of PCOS women are required. BACKGROUND: Anti-Müllerian hormone (AMH) is secreted by granulosa cells of ovarian early developing follicles and its serum levels have been shown to correlate with small antral follicle number. Since the pronounced androgen secretion from follicles/stroma in women with polycystic ovary syndrome (PCOS) remains until late reproductive age, and since AMH reflects the number of antral follicles, it was of interest to study the possible age-related relationship between AMH, androgens and follicle number in women with PCOS and in control women. Moreover, the possible effect of metformin on serum AMH levels and the relationship to follicle count and volume were studied. METHODS: Forty-four healthy women (aged 21-44 years) and 65 women with previously diagnosed PCOS (aged 16-44 years) participated in the study. Serum basal AMH levels were correlated with those of serum androstenedione, testosterone, estradiol (E2), LH, FSH and inhibin B, and with follicle number. The effect of metformin on serum AMH concentrations, follicle number and ovarian volume was studied in 26 women (aged 20-41 years) with PCOS after 6 months of treatment. RESULTS: Serum AMH levels were 2- to 3- fold higher in PCOS women than in healthy women. In control women, serum AMH levels correlated positively with those of serum androstenedione (r = 0.564, P < 0.001) and testosterone (r = 0.328, P = 0.036) and negatively with serum FSH concentrations (r = -0.374, P = 0.012) and age (r = -0.691, P<0.001). In women with PCOS, serum AMH levels correlated positively with those of androstenedione (r = 0.311, P = 0.011) and testosterone (r = 0.310, P = 0.011) and with follicle count (r = 0.352, P = 0.012), and negatively with age (r = -0.300, P = 0.014). Serum AMH levels, the number of antral follicles and ovarian volume decreased significantly during metfromin treatment. CONCLUSIONS: Serum AMH levels decreased with age both in healthy women and in women with PCOS, although they were always 2- to 3-fold higher and remained elevated until 40 years of age in PCOS subjects. Thus, since serum AMH levels correlate well with antral follicle count and serum androgen levels, the measurement of AMH could be used as a tool to assess ovarian ageing, to diagnose polycystic ovaries/PCOS and to evaluate treatment efficacy. BACKGROUND: Metformin has failed to gain wide acceptance as a first-line treatment option for women with anovulatory infertility related to polycystic ovary syndrome. This study aimed to ascertain factors that predict fertility success with treatment that included metformin compared to standard (non-metformin) treatment. METHODS: Randomised trial data analysis by logistic regression of factors likely to have a differential influence on the likelihood of success of metformin versus non-metformin treatment amongst women with ovulation dysfunction related to polycystic ovary syndrome. RESULTS: metformin versus those receiving placebo and those with lower BMI who received metformin were more likely to become pregnant than their lower BMI counterparts who received placebo (P=0.039). The subpopulation of women with BMI≤32 kg/m(2) had no factors showing a significantly different impact on the chance of pregnancy for women treated with metformin versus those receiving clomiphene treatment or combination metformin/clomiphene treatment versus clomiphene treatment. There were no significantly different effects of free testosterone, fasting insulin, duration of infertility or ultrasound appearance of polycystic ovaries in any treatment groups. CONCLUSION: This study provides preliminary evidence that BMI may be an important prognostic factor in response to metformin for women with ovulation dysfunction related to polycystic ovary syndrome, suggesting that women with a lower BMI may respond better to metformin treatment versus placebo amongst women with BMI>32 kg/m(2) . Individual patient data meta-analysis of existing randomised trials would clarify this further and would assess whether other factors might predict better response to metformin versus standard treatments. AIM: Polycystic ovary syndrome (PCOS) is a multifactorial pathology affecting 5-10% of the female population. Usually occurs with oligo/amenorrhea, anovulation, hirsutism, polycystic ovaries. Hyperinsulinemia associated with insulin resistance has been causally linked to all features of the syndrome. It has been demonstrated that by reducing hyperinsulinemia, in particular with the administration of metformin, insulin-lowering agents might improve endocrine and reproductive abnormalities in PCOS patients. METHODS: A new molecule with insulin-sensitizing properties, myo-inositol, has recently been successfully administered in women with PCOS. New associations between natural substances like myo-inositol and other components have been proposed to improve the therapeutical efficacy. Among these substances, the monacolin K, a natural statin appeared to have important actions in cholesterol synthesis. In this article we study the effect of inositol alone and the association between myo-inositol and monacolinin K in the treatment of PCOS with insulin resistance, menstrual irregularities and hirsutism. RESULTS AND CONCLUSION: The results of this study demonstrated a good efficacy of both treatments, although in the group treated with the combination of myo-inositol/monacolin K improvement in lipids and hyperandrogenism were significantly better. The syndrome of polycystic ovaries (PCOS) is associated with adiposity and metabolic changes predisposing to insulin resistance and diabetes mellitus. Because the recently discovered GH secretagogue, ghrelin, is intimately involved in the control of appetite and weight regulation, we studied ghrelin levels in a group of 26 otherwise healthy women with PCOS. They were compared with 61 healthy female control subjects and 5 gastrectomized women. Insulin sensitivity was assessed by homeostasis model assessment (HOMA) and continuous infusion of glucose with model assessment (CIGMA) in all patients. In PCOS women, serum ghrelin levels were significantly lower than in healthy lean or obese controls (P < 0.001). In insulin-sensitive PCOS women, ghrelin concentrations compared well with the healthy controls, whereas in insulin-resistant PCOS ghrelin levels were significantly lower and indistinguishable from the low levels found in the gastrectomized women. There was a close correlation of ghrelin to insulin sensitivity (HOMA, r(2) = 0.330, P < 0.002; CIGMA, r(2) = 0.568, P < 0.0001). Treatment of 10 insulin-resistant PCOS women with metformin significantly increased circulating fasting ghrelin concentrations (P < 0.02). Ghrelin levels did not correlate to any of the parameters of hyperandrogenemia, to the LH/FSH ratio, to body mass index, or to fasting insulin and glucose concentrations. In summary, ghrelin levels are decreased in PCOS women and are highly correlated to the degree of insulin resistance. This suggests that ghrelin could be linked to insulin resistance in PCOS women. However, whether low ghrelin in PCOS is a cause or the consequence of insulin resistance awaits further investigations. BACKGROUND: Current data suggest that excessive androgen exposure can lead to the development of polycystic ovaries and polycystic ovary syndrome (PCOS). Anti-Müllerian hormone (AMH) levels reflect the number of small antral follicles in the ovaries and are elevated in PCOS. We hypothesized that protracted reduction of circulating androgens and/or insulin resistance would reduce circulating AMH concentrations in women with PCOS. METHODS: A prospective, randomized, double-blind 26 week long study was undertaken in 50 women with PCOS. They all received diet and lifestyle counselling, and metformin 850 mg three times daily. Concomitantly, they were randomized to either dexamethasone 0.25 mg daily (n = 25) or placebo (n = 25). Thirty-eight women completed the study. AMH (primary outcome) and other hormone levels were measured at inclusion and after 8 and 26 weeks of treatment. RESULTS: At baseline in univariate regression analyses, AMH levels associated positively with testosterone levels (P = 0.041) and ovarian volume (P = 0.002). In multivariate regression analyses, AMH associated positively with testosterone P = 0.004), and negatively with dehydroepiandrosterone sulphate (DHEAS) (P = 0.001) and C-peptide levels (P = 0.020). Circulating AMH concentrations were unaffected by 6 months of lifestyle counselling with metformin and placebo treatment. AMH levels were also unaffected by 6 months of androgen suppression with dexamethasone in addition. CONCLUSIONS: AMH levels in untreated PCOS women associated positively with testosterone, and negatively with DHEAS and C-peptide levels. Six months of androgen suppression by either metformin or low-dose dexamethasone treatment failed to influence circulating AMH levels. Women with oligomenorrhea and polycystic ovaries show a high incidence of ovulation failure perhaps linked to insulin resistance and related metabolic features. A number of reports show that the biguanide metformin improves ovarian function. However, in these trials the quality of evidence supporting ovulation is suboptimal, and few studies have been placebo-controlled. The aim of our study was to use a double-blind, placebo-controlled approach with detailed assessment of ovarian activity (two blood samples per week) to assess the validity of this therapeutic approach in this group of women. Of the 94 patients randomized, 2 withdrew before treatment commenced, 47 received placebo, and 45 received metformin (850 mg, twice a day). The numbers discontinuing the study prematurely were higher in the treatment group (n = 15) than the placebo group (n = 5; P < 0.05). The ovulation frequency assessed by the ratio of luteal phase weeks to observation weeks was significantly (P < 0.01) higher in the treated group (23%) compared with the placebo (13%), and the time to first ovulation was significantly (P < 0.05) shorter [23.6 d; 95% confidence interval (CI), 17, 30; compared with 41.8 d; 95% CI, 28, 56]. The proportion of patients failing to ovulate during the placebo-treatment period was higher (P < 0.05) in the placebo group, and the majority of ovulations were characterized by normal progesterone concentrations in both groups. The effect of metformin on follicular maturation was rapid, because the E2 circulating concentration increased over the first week of treatment only in the metformin group. Significant (P < 0.01) weight loss (and leptin reduction) was recorded in the metformin group, whereas the placebo group actually increased weight (P < 0.05). A significant increase in circulating high-density lipoprotein was observed only in the metformin-treated group. Metabolic risk factor benefits of metformin treatment were not observed in the morbidly obese subgroup of patients (body mass index > 37). No change in fasting glucose concentrations, fasting insulin, or insulin responses to glucose challenge was recorded after 14-wk metformin or placebo therapy. There was an inverse relationship between body mass and treatment efficacy. We show in a large randomized placebo-controlled trial that metformin treatment improves ovulation frequency in women with abnormal ovarian function and polycystic ovaries significantly but to a modest degree, and protracted treatment improves cardiovascular risk factors. These data support a beneficial effect of metformin in improving ovarian function in women with oligomenorrhea and polycystic ovaries. |
347 | List the main proteases used for sample digestion in proteomics. | Trypsin is the main protease used in proteomics followed by Asp-N, chymotrypsin, LysC, GluC and thermolysin. | [24116745, 24168082, 23710360, 23703833, 23792921, 23728546, 24144163, 23943586, 24140975, 23819575, 24133050, 23580477, 22324799, 23576383, 24136523, 24106208, 23454304, 23775586, 23606249, 20218731, 24012793] | 454 | Implementation of quantitative clinical chemistry proteomics (qCCP) requires targeted proteomics approaches, usually involving bottom-up multiple reaction monitoring-mass spectrometry (MRM-MS) with stable-isotope labeled standard (SIS) peptides, to move toward more accurate measurements. Two aspects of qCCP that deserve special attention are (1) proper calibration and (2) the assurance of consistent digestion. Here, we describe the evaluation of tryptic digestion efficiency by monitoring various signature peptides, missed cleavages, and modifications during proteolysis of apolipoprotein A-I and B in normo- and hypertriglyceridemic specimens. Absolute quantification of apolipoprotein A-I and B was performed by LC-MRM-MS with SIS peptide internal standards at two time points (4 and 20 h), using three native protein calibrators. Comparison with an immunoturbidimetric assay revealed recoveries of 99.4 ± 6.5% for apolipoprotein A-I and 102.6 ± 7.2% for apolipoprotein B after 4 h of trypsin digestion. Protein recoveries after 20 h trypsin incubation equaled 95.9 ± 6.9% and 106.0 ± 10.0% for apolipoproteins A-I and B, respectively. In conclusion, the use of metrologically traceable, native protein calibrators looks promising for accurate quantification of apolipoprotein A-I and B. Selection of rapidly formed peptides, that is, with no or minor missed cleavages, and the use of short trypsin incubation times for these efficiently cleaved peptides are likely to further reduce the variability introduced by trypsin digestion and to improve the traceability of test results to reach the desirable analytical performance for clinical chemistry application. The majority of mass spectrometry-based protein quantification studies uses peptide-centric analytical methods and thus strongly relies on efficient and unbiased protein digestion protocols for sample preparation. We present a novel objective approach to assess protein digestion efficiency using a combination of qualitative and quantitative liquid chromatography-tandem MS methods and statistical data analysis. In contrast to previous studies we employed both standard qualitative as well as data-independent quantitative workflows to systematically assess trypsin digestion efficiency and bias using mitochondrial protein fractions. We evaluated nine trypsin-based digestion protocols, based on standard in-solution or on spin filter-aided digestion, including new optimized protocols. We investigated various reagents for protein solubilization and denaturation (dodecyl sulfate, deoxycholate, urea), several trypsin digestion conditions (buffer, RapiGest, deoxycholate, urea), and two methods for removal of detergents before analysis of peptides (acid precipitation or phase separation with ethyl acetate). Our data-independent quantitative liquid chromatography-tandem MS workflow quantified over 3700 distinct peptides with 96% completeness between all protocols and replicates, with an average 40% protein sequence coverage and an average of 11 peptides identified per protein. Systematic quantitative and statistical analysis of physicochemical parameters demonstrated that deoxycholate-assisted in-solution digestion combined with phase transfer allows for efficient, unbiased generation and recovery of peptides from all protein classes, including membrane proteins. This deoxycholate-assisted protocol was also optimal for spin filter-aided digestions as compared with existing methods. Dried blood spots offer many advantages as a sample format including ease and safety of transport and handling. To date, the majority of mass spectrometry analyses of dried blood spots have focused on small molecules or hemoglobin. However, dried blood spots are a potentially rich source of protein biomarkers, an area that has been overlooked. To address this issue, we have applied an untargeted bottom-up proteomics approach to the analysis of dried blood spots. We present an automated and integrated method for extraction of endogenous proteins from the surface of dried blood spots and sample preparation via trypsin digestion by use of the Advion Biosciences Triversa Nanomate robotic platform. Liquid chromatography tandem mass spectrometry of the resulting digests enabled identification of 120 proteins from a single dried blood spot. The proteins identified cross a concentration range of four orders of magnitude. The method is evaluated and the results discussed in terms of the proteins identified and their potential use as biomarkers in screening programs. Workflows in bottom-up proteomics have traditionally implemented the use of proteolysis during sample preparation; enzymatic digestion is most commonly performed using trypsin. This results in the hydrolysis of peptide bonds forming tryptic peptides, which can then be subjected to LC-MS/MS analysis. While the structure, specificity, and kinetics of trypsin are well characterized, a lack of consensus and understanding has remained regarding fundamental parameters critical to obtaining optimal data from a proteomics experiment. These include the type of trypsin used, pH during digestion, incubation temperature as well as enzyme-to-substrate ratio. Through the use of design of experiments (DOE), we optimized these parameters, resulting in deeper proteome coverage and a greater dynamic range of measurement. The knowledge gained from optimization of a discovery-based proteomics experiment was applied to targeted LC-MS/MS experiments using protein cleavage-isotope dilution mass spectrometry for absolute quantification. We demonstrated the importance of these digest parameters with respect to our limit of detection as well as our ability to acquire more accurate quantitative measurements. Additionally, we were able to quantitatively account for peptide decay observed in previous studies, caused by nonspecific activity of trypsin. The tryptic digest optimization described here has eliminated this previously observed peptide decay as well as provided a greater understanding and standardization for a common but critical sample treatment used across the field of proteomics. The in-depth analysis of complex proteome samples requires fractionation of the sample into subsamples prior to LC-MS/MS in shotgun proteomics experiments. We have established a 3D workflow for shotgun proteomics that relies on protein separation by 1D PAGE, gel fractionation, trypsin digestion, and peptide separation by in-gel IEF, prior to RP-HPLC-MS/MS. Our results show that applying peptide IEF can significantly increase the number of proteins identified from PAGE subfractionation. This method delivers deeper proteome coverage and provides a large degree of flexibility in experimentally approaching highly complex mixtures by still relying on protein separation according to molecular weight in the first dimension. In this study, soft-shelled turtle (Pelodiscus sinensis) egg white (SSTEW) proteins were digested by thermolysin and the resulting small peptides were further fractionated by reverse phase chromatography. Peptides with angiotensin I-converting enzyme inhibitory (ACEI) activity from these fractions were screened. A lysozyme-derived peptide, IW-11, from the fraction with the most effective ACEI was identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and its purified form showed effective ACEI activity in vitro (IC50=4.39±0.31μM). The Lineweaver-Burk plots indicated that the inhibition towards ACE caused by this peptide is a competitive inhibition. The molecular docking study further revealed that the ACEI activity of IW-11 is mainly attributed to the formation of hydrogen bonds between the N-terminal residue of IW-11 and the S1 pocket (Ala354 and Tyr523) and the S2' region (His513 and His353) of ACE. Moreover, the digestion parameters were further optimized and the target peptide (82% purity) was readily obtained (15% yield) without any cumbersome purification procedure. Notably, lysozyme C is the most abundant protein in SSTEW, which implies that an efficient production of this ACEI peptide from SSTEW is promising. BIOLOGICAL SIGNIFICANCE: Inhibition of ACE has proven to be an effective strategy in prevention and treatment of hypertension and related diseases. Unlike typical synthetic ACE inhibitors which exert well described side effects, food-derived peptides with ACE inhibitory activity may be safer alternatives for hypertension treatment. In this study, we comprehensively identified peptides derived from SSTEW digest using a proteomic approach. IW-11, which is derived from lysozyme, the most abundant protein in SSTEW, showed remarkable inhibition towards ACE. This peptide has been demonstrated to have a competitive inhibitory property which is able to bind to ACE active site and found to be a true inhibitor against ACE according to Lineweaver-Burk plots. Using an optimized thermolysin condition, IW-11 can be readily obtained without any complex purification step, which will benefit its further application to prevention or treatment of hypertension. Gan et al. (Proteomics 2013, 13, 3117-3123) described a new "macropore" protocol for effective protein digestion by trypsin suitable for a wide range of pH including acidic pH. It was effective not only in experiments with solutions of a model protein (myoglobin), but also with a subfraction of rat liver cytosol. This significantly simplifies and accelerates protein digestion procedures for subsequent MS. However, further studies are needed to find limits of experimental applicability of the described protocol in proteomics. Analytical advantages of using multiple enzymes for sample digestion (MED), primarily an increase of sequence coverage, have been reported in several studies. However, this approach is only rarely used, mainly because it requires additional sample and mass spectrometric measurement time. We have previously described Filter Aided Sample Preparation (FASP), a type of proteomic reactor, in which samples dissolved in sodium dodecyl sulfate (SDS) are digested in an ultrafiltration unit. In FASP, such as in any other preparation protocol, a portion of sample remains after digestion and peptide elution. Making use of this fact, we here develop a protocol enabling consecutive digestion of the sample with two or three enzymes. By use of the FASP method, peptides are liberated after each digestion step and remaining material is subsequently cleaved with the next proteinase. We observed excellent performance of the ultrafiltration devices in this mode, allowing efficient separation of orthogonal populations of peptides, resulting in an increase in the numbers of identified peptides and proteins. At the low microgram level, we found that the consecutive use of endoproteinases LysC and trypsin enabled identification of up to 40% more proteins and phosphorylation sites in comparison to the commonly used one-step tryptic digestion. MED-FASP offers efficient exploration of previously unused sample material, increasing depth of proteomic analyses and sequence coverage. Oil bodies, lipid-storage organelles, are stabilized by a number of specific proteins. These proteins are very hydrophobic, which complicates their identification by "classical" proteomic protocols using trypsin digestion. Due to the lack of trypsin cleavage sites, the achievable protein coverage is limited or even insufficient for reliable protein identification. To identify such proteins and to enhance their coverage, we introduced a modified method comprising standard three-step procedure (SDS-PAGE, in-gel digestion, and LC-MS/MS analysis). In this method, chymotrypsin, single or in combination with trypsin, was used, which enabled to obtain proteolytic peptides from the hydrophobic regions and to identify new oil bodies' proteins. Our method can be easily applied to identification of other hydrophobic proteins. Nowadays, mass spectrometry-based proteomics is carried out primarily in a bottom-up fashion, with peptides obtained after proteolytic digest of a whole proteome lysate as the primary analytes instead of the proteins themselves. This experimental setup crucially relies on a protease to digest an abundant and complex protein mixture into a far more complex peptide mixture. Full knowledge of the working mechanism and specificity of the used proteases is therefore crucial, both for the digestion step itself as well as for the downstream identification and quantification of the (fragmentation) mass spectra acquired for the peptides in the mixture. Targeted protein analysis through selected reaction monitoring, a relative newcomer in the specific field of mass spectrometry-based proteomics, even requires a priori understanding of protease behavior for the proteins of interest. Because of the rapidly increasing popularity of proteomics as an analytical tool in the life sciences, there is now a renewed demand for detailed knowledge on trypsin, the workhorse protease in proteomics. This review addresses this need and provides an overview on the structure and working mechanism of trypsin, followed by a critical analysis of its cleavage behavior, typically simply accepted to occur exclusively yet consistently after Arg and Lys, unless they are followed by a Pro. In this context, shortcomings in our ability to understand and predict the behavior of trypsin will be highlighted, along with the downstream implications. Furthermore, an analysis is carried out on the inherent shortcomings of trypsin with regard to whole proteome analysis, and alternative approaches will be presented that can alleviate these issues. Finally, some reflections on the future of trypsin as the workhorse protease in mass spectrometry-based proteomics will be provided. Proteomic profiling of heart tissue might help to discover the molecular events related to or even causing cardiovascular diseases in human. However, this material is rare and only available from biopsies taken for diagnostics, e.g., assessment of inflammatory events or virus persistence. Within this chapter, we describe a workflow for the quantitative proteome analysis of heart biopsies. Starting with 1-2 mg of tissue material, crude protein extracts were prepared, digested with LysC and trypsin, and then analyzed by LC-ESI-tandem mass spectrometry. Due to the low technical variance, the method can be used for label-free quantitation of disease-specific alterations in the human heart. Methods discussed include homogenization of biopsy tissue, sample preparation, proteolytic digestion, as well as data analysis for label-free quantitation. Quantitative proteomics using isobaric labeling typically involves sample digestion, peptide-level labeling and 2D LC-MS/MS. Proteomic analysis of complex samples can potentially be performed more comprehensively with GeLC-MS/MS. However, combining this approach with peptide-level labeling of multiple in-gel digests from entirely sectioned gel lanes can introduce many points of variation and adversely affect the final quantitative accuracy. Alternatively, samples labeled with isobaric tags at the protein level can be combined and analyzed by GeLC-MS/MS as a single gel lane. A caveat to this strategy is that only lysine residues are labeled, which might limit protein digestion and quantitation of peptides. Here we have compared a protein-level labeling GeLC-MS/MS strategy with a peptide-level labeling 2D LC-MS/MS approach, using mouse hippocampus synaptosomes and isobaric tandem mass tags. Protein-level labeling enabled the identification of 3 times more proteins (697 versus 241) than did peptide-level labeling, and importantly for quantitation, twice as many proteins with labeled peptides (480 versus 232) were identified. Preliminary in silico analysis also suggested the alternative use of Asp-N to trypsin to circumvent the interference of lysine labeling on protein digestion. Use of Asp-N resulted in the effective analysis of fewer peptides than with trypsin for the protein-level approach (1677 versus 3131), but yielded a similar quantitative proteomic coverage in terms of both peptides (1150 versus 1181) and proteins (448 versus 480). Taken together, these experiments demonstrate that protein-level labeling combined with GeLC-MS/MS is an effective strategy for the multiplexed quantitation of synaptosomal preparations, and may also be applicable to samples of a similar proteomic complexity and dynamic range of protein abundance. Immune complexome analysis is a method for identifying and profiling of antigens in circulating immune complexes (CICs); it involves separation of immune complexes from serum, direct tryptic digestion of these complexes, and protein analysis via nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS). To improve this method, we initially investigated the effects of two factors-the gradient elution program and nano-LC column type (C18-packed, C8-packed, or packed spray capillary column)-on the numbers of peptides and proteins identified. Longer gradient elution times resulted in higher identification capability throughout the range of 25-400 min. Moreover, the packed spray capillary column supported identification of more peptides and proteins than did any other column. In addition, microwave-assisted digestion was compared with conventional digestion, which involved incubation overnight at 37 °C. Microwave-assisted digestion produced more partially digested peptides than did conventional digestion. However, the percentages of miscleaved peptides in all of the identified peptides in microwave-assisted digestion of immune complexes (a protein mixture) were lower than those in the physical stimulation-assisted digestion of a model protein. Microwave-assisted digestion is slightly inferior to, or as effective as, conventional digestion, but it drastically reduces the digestion time. |
348 | Which proteins act as factors that promote transcription-coupled repair in bacteria? | Transcription coupled nucleotide excision repair (TC-NER or TCR) is a cellular process by which UV-induced damage and other road-blocks encountered in the transcribed strand are restored. Bacterial transcription-coupled repair is initiated when RNA polymerase stalled at a DNA lesion is removed by Mfd (Mutation frequency decline), an ATP-dependent DNA translocase. Mfd is the major transcription repair coupling factor in bacteria. Also, the transcription elongation factor NusA, in addition to its role in recruiting translesion synthesis (TLS) DNA polymerases to gaps encountered during transcription, promotes an alternative class of TCR involved in the identification and removal of a class of lesion, such as the N(2)-f-dG lesion. | [21145481, 12086674, 21559463, 24118570, 20110508, 20436399, 20696893, 20638914, 16469698, 7869378, 18707026, 22749141, 15687384, 20702425, 24554077, 22960746, 22427630, 9535092, 20178806, 8807287, 17572090] | 455 | Transcription-coupled DNA repair (TCR) is a subpathway of nucleotide excision repair (NER) that is triggered when RNA polymerase is stalled by DNA damage. Lesions targeted by TCR are repaired more quickly than lesions repaired by the transcription-independent "global" NER pathway, but the mechanism underlying this rate enhancement is not understood. Damage recognition during bacterial NER depends upon UvrA, which binds to the damage and loads UvrB onto the DNA. Bacterial TCR additionally requires the Mfd protein, a DNA translocase that removes the stalled transcription complexes. We have determined the properties of Mfd, UvrA, and UvrB that are required for the elevated rate of repair observed during TCR. We show that TCR and global NER differ in their requirements for damage recognition by UvrA, indicating that Mfd acts at the very earliest stage of the repair process and extending the functional similarities between TCR in bacteria and eukaryotes. Transcription and DNA repair are coupled in E. coli by the Mfd protein, which dissociates transcription elongation complexes blocked at nonpairing lesions and mediates recruitment of DNA repair proteins. We show that Mfd influences the elongation state of RNA polymerase (RNAP); transcription complexes that have reverse translocated into the backtracked position, a potentially important intermediate in RNA proofreading and repair, are restored to the forward position by the activity of Mfd, and arrested complexes are rescued into productive elongation. Mfd may act through a translocase activity that rewinds upstream DNA, leading either to translocation or to release of RNA polymerase when the enzyme active site cannot continue elongation. Transcription coupled nucleotide excision repair (TC-NER) is involved in correcting UV-induced damage and other road-blocks encountered in the transcribed strand. Mutation frequency decline (Mfd) is a transcription repair coupling factor, involved in repair of template strand during transcription. Mfd from M. tuberculosis (MtbMfd) is 1234 amino-acids long harboring characteristic modules for different activities. Mtbmfd complemented Escherichia coli mfd (Ecomfd) deficient strain, enhanced survival of UV irradiated cells and increased the road-block repression in vivo. The protein exhibited ATPase activity, which was stimulated ∼1.5-fold in the presence of DNA. While the C-terminal domain (CTD) comprising amino acids 630 to 1234 showed ∼2-fold elevated ATPase activity than MtbMfd, the N-terminal domain (NTD) containing the first 433 amino acid residues was able to bind ATP but deficient in hydrolysis. Overexpression of NTD of MtbMfd led to growth defect and hypersensitivity to UV light. Deletion of 184 amino acids from the C-terminal end of MtbMfd (MfdΔC) increased the ATPase activity by ∼10-fold and correspondingly exhibited efficient translocation along DNA as compared to the MtbMfd and CTD. Surprisingly, MtbMfd was found to be distributed in monomer and hexamer forms both in vivo and in vitro and the monomer showed increased susceptibility to proteases compared to the hexamer. MfdΔC, on the other hand, was predominantly monomeric in solution implicating the extreme C-terminal region in oligomerization of the protein. Thus, although the MtbMfd resembles EcoMfd in many of its reaction characteristics, some of its hitherto unknown distinct properties hint at its species specific role in mycobacteria during transcription-coupled repair. In conditions of halted or limited genome replication, like those experienced in sporulating cells of Bacillus subtilis, a more immediate detriment caused by DNA damage is altering the transcriptional programme that drives this developmental process. Here, we report that mfd, which encodes a conserved bacterial protein that mediates transcription-coupled DNA repair (TCR), is expressed together with uvrA in both compartments of B. subtilis sporangia. The function of Mfd was found to be important for processing the genetic damage during B. subtilis sporulation. Disruption of mfd sensitized developing spores to mitomycin-C (M-C) treatment and UV-C irradiation. Interestingly, in non-growing sporulating cells, Mfd played an anti-mutagenic role as its absence promoted UV-induced mutagenesis through a pathway involving YqjH/YqjW-mediated translesion synthesis (TLS). Two observations supported the participation of Mfd-dependent TCR in spore morphogenesis: (i) disruption of mfd notoriously affected the efficiency of B. subtilis sporulation and (ii) in comparison with the wild-type strain, a significant proportion of Mfd-deficient sporangia that survived UV-C treatment developed an asporogenous phenotype. We propose that the Mfd-dependent repair pathway operates during B. subtilis sporulation and that its function is required to eliminate genetic damage from transcriptionally active genes. In vivo studies suggest that replication forks are arrested by encounters with head-on transcription complexes. Yet, the fate of the replisome and RNA polymerase (RNAP) after a head-on collision is unknown. We found that the Escherichia coli replisome stalls upon collision with a head-on transcription complex, but instead of collapsing, the replication fork remains highly stable and eventually resumes elongation after displacing the RNAP from DNA. We also found that the transcription-repair coupling factor Mfd promotes direct restart of the fork after the collision by facilitating displacement of the RNAP. These findings demonstrate the intrinsic stability of the replication apparatus and a previously unknown role for the transcription-coupled repair pathway in promoting replication past a RNAP block. Transcription-coupled nucleotide excision repair (TC-NER) removes certain kinds of lesions from the transcribed strand of expressed genes. The signal for TC-NER is thought to be RNA polymerase stalled at a lesion in the DNA template. In Escherichia coli, the stalled polymerase is dissociated from the lesion by the transcription repair coupling factor (Mfd protein), which also recruits excision repair proteins to the site resulting in efficient removal of the lesion. TC-NER has been documented in cells from a variety of organisms ranging from bacteria to humans. In each case, the RNA polymerase involved has been a multimeric protein complex. To ascertain whether a gene transcribed by the monomeric RNA polymerase of bacteriophage T7 could be repaired by TC-NER, we constructed strains of E. coli in which the chromosomal lacZ gene is controlled by a T7 promoter. In the absence of T7 RNA polymerase, little or no beta-galactosidase is produced, indicating that the E. coli RNA polymerase does not transcribe lacZ efficiently, if at all, in these strains. By introducing a plasmid (pAR1219) carrying the T7 gene 1 under control of the E. coli lac UV5 promoter into these strains, we obtained derivatives in which the level of T7 RNA polymerase could be regulated. In cultures containing upregulated levels of the polymerase, beta-galactosidase was actively produced indicating that the T7 RNA polymerase transcribes the lacZ gene efficiently. Under these conditions, we observed that UV-induced cyclobutane pyrimidine dimers were removed more rapidly from the transcribed strand of lacZ than from the nontranscribed strand, supporting the conclusion that TC-NER occurred in this gene. This response was absent in an mfd-1 mutant, indicating that the underlying mechanism may be similar to that for the bacterial RNA polymerase. Coupling of transcription and DNA repair in bacteria is mediated by transcription-repair coupling factor (TRCF, the product of the mfd gene), which removes transcription elongation complexes stalled at DNA lesions and recruits the nucleotide excision repair machinery to the site. Here we describe the 3.2 A-resolution X-ray crystal structure of Escherichia coli TRCF. The structure consists of a compact arrangement of eight domains, including a translocation module similar to the SF2 ATPase RecG, and a region of structural similarity to UvrB. Biochemical and genetic experiments establish that another domain with structural similarity to the Tudor-like domain of the transcription elongation factor NusG plays a critical role in TRCF/RNA polymerase interactions. Comparison with the translocation module of RecG as well as other structural features indicate that TRCF function involves large-scale conformational changes. These data, along with a structural model for the interaction of TRCF with the transcription elongation complex, provide mechanistic insights into TRCF function. Heterogeneity of DNA repair has been observed at different levels of genomic organization, including chromatin domains, expressed genes and DNA strands. If heterogeneity also existed intragenically, it could reveal fine details of the excision repair mechanism in vivo. Here we measure the frequency of UV-induced cyclobutane pyrimidine dimers at individual nucleotides within defined portions of two Escherichia coli genes, lacl and lacZ, at various times after irradiation. Two domains of differential repair rates were apparent, with repair being slow at nucleotides adjacent to the transcription start sites. In lacZ, the domain of faster repair began 32 bases downstream of the transcription start site and required the mfd gene. Since mfd codes for a transcription-repair coupling factor, this transcription-coupled repair system evidently becomes operative downstream of the initiation complex region in vivo. Unexpectedly, however, (1) an mfd mutation reduced repair in the downstream domain even when transcription was at a very low level and (2) induction of lacZ transcription with isopropyl-beta-D-thiogalactoside overcame this reduction. Evidently, the Mfd transcription-repair coupling factor is required for basal levels of strand-specific repair in this gene, but induced levels of repair are related to transcription through another mechanism. Transcription-coupled repair (TCR) is a subpathway of nucleotide excision repair (NER) that acts specifically on lesions in the transcribed strand of expressed genes. First reported in mammalian cells, TCR was then documented in Escherichia coli. In this organism, an RNA polymerase arrested at a lesion is displaced by the transcription repair coupling factor, Mfd. This protein recruits the NER lesion-recognition factor UvrA, and then dissociates from the DNA. UvrA binds UvrB, and the assembled UvrAB* complex initiates repair. In mutants lacking active Mfd, TCR is absent. A gene transcribed by the bacteriophage T7 RNA polymerase in E. coli also requires Mfd for TCR. The CSB protein (missing or defective in cells of patients with Cockayne syndrome, complementation group B) is essential for TCR in humans. CSB and its homologs in higher eukaryotes are likely functional equivalents of Mfd. The bacterial Mfd protein is a transcription-repair coupling factor that performs two key functions during transcription-coupled DNA repair. The first is to remove RNA polymerase (RNAP) complexes that have been stalled by a DNA lesion from the site of damage, and the second is to mediate the recruitment of DNA repair proteins. Mfd also displaces transcription complexes that have been stalled by protein roadblocks, and catalyses the reactivation of transcription complexes that have become 'backtracked'. We have identified amino acid substitutions in the beta subunit of Escherichia coli RNAP that disrupt a direct interaction between Mfd and RNAP. These substitutions prevent Mfd displacing stalled RNAP from DNA in vivo and in vitro. They define a highly conserved surface-exposed patch on the beta1 domain of RNAP that is required by Mfd for the initial step of transcription-coupled repair, the enhancement of roadblock repression and the reactivation of backtracked transcription complexes. Transcription-coupled nucleotide excision repair (TCR) accelerates the removal of noncoding lesions from the template strand of active genes, and hence contributes to genome-wide variations in mutation frequency. Current models for TCR suppose that a lesion must cause RNA polymerase (RNAP) to stall if it is to be a substrate for accelerated repair. We have examined the substrate requirements for TCR using a system in which transcription stalling and damage location can be uncoupled. We show that Mfd-dependent TCR in bacteria involves the formation of a damage search complex that can detect lesions downstream of a stalled RNAP, and that the strand specificity of the accelerated repair pathway is independent of the requirement for a lesion to stall RNAP. We also show that an ops (operon polarity suppressor) transcription pause site, which causes backtracking of RNAP, can promote the repair of downstream lesions when those lesions do not themselves cause the polymerase to stall. Our findings indicate that the transcription-repair coupling factor Mfd, which is an ATP-dependent superfamily 2 helicase that binds to RNAP, continues to translocate along DNA after RNAP has been displaced until a lesion in the template strand is located. The discovery that pause sites can promote the repair of nonstalling lesions suggests that TCR pathways may play a wider role in modulating mutation frequencies in different parts of the genome than has previously been suspected. Transcription-coupled DNA repair uses components of the transcription machinery to identify DNA lesions and initiate their repair. These repair pathways are complex, so their mechanistic features remain poorly understood. Bacterial transcription-coupled repair is initiated when RNA polymerase stalled at a DNA lesion is removed by Mfd, an ATP-dependent DNA translocase. Here we use single-molecule DNA nanomanipulation to observe the dynamic interactions of Escherichia coli Mfd with RNA polymerase elongation complexes stalled by a cyclopyrimidine dimer or by nucleotide starvation. We show that Mfd acts by catalysing two irreversible, ATP-dependent transitions with different structural, kinetic and mechanistic features. Mfd remains bound to the DNA in a long-lived complex that could act as a marker for sites of DNA damage, directing assembly of subsequent DNA repair factors. These results provide a framework for considering the kinetics of transcription-coupled repair in vivo, and open the way to reconstruction of complete DNA repair pathways at single-molecule resolution. Transcription-coupled repair (TCR) is a cellular process by which some forms of DNA damage are repaired more rapidly from transcribed strands of active genes than from nontranscribed strands or the overall genome. In humans, the TCR coupling factor, CSB, plays a critical role in restoring transcription following both UV-induced and oxidative DNA damage. It also contributes indirectly to the global repair of some forms of oxidative DNA damage. The Escherichia coli homolog, Mfd, is similarly required for TCR of UV-induced lesions. However, its contribution to the restoration of transcription and to global repair of oxidative damage has not been examined. Here, we report the first direct study of transcriptional recovery following UV-induced and oxidative DNA damage in E. coli. We observed that mutations in mfd or uvrA reduced the rate that transcription recovered following UV-induced damage. In contrast, no difference was detected in the rate of transcription recovery in mfd, uvrA, fpg, nth, or polB dinB umuDC mutants relative to wild-type cells following oxidative damage. mfd mutants were also fully resistant to hydrogen peroxide (H(2)O(2)) and removed oxidative lesions from the genome at rates comparable to wild-type cells. The results demonstrate that Mfd promotes the rapid recovery of gene expression following UV-induced damage in E. coli. In addition, these findings imply that Mfd may be functionally distinct from its human CSB homolog in that it does not detectably contribute to the recovery of gene expression or global repair following oxidative damage. Transcription-coupled repair, the targeted repair of the transcribed strands of active genes, is defective in bacteria, yeast, and human cells carrying mutations in mfd, RAD26 and ERCC6, respectively. Other factors probably are also uniquely involved in transcription-repair coupling. Recently, a defect was described in transcription-coupled repair for Escherichia coli mismatch repair mutants and human tumor cell lines with mutations in mismatch repair genes. We examined removal of UV-induced DNA damage in yeast strains mutated in mismatch repair genes in an effort to confirm a defect in transcription-coupled repair in this system. In addition, we determined the contribution of the mismatch repair gene MSH2 to transcription-coupled repair in the absence of global genomic repair using rad7 delta mutants. We also determined whether the Rad26-independent transcription-coupled repair observed in rad26 delta and rad7 delta rad26 delta mutants depends on MSH2 by examining repair deficiencies of rad26 delta msh2 delta and rad7 delta rad26 delta msh2 delta mutants. We found no defects in transcription-coupled repair caused by mutations in the mismatch repair genes MSH2, MLH1, PMS1, and MSH3. Yeast appears to differ from bacteria and human cells in the capacity for transcription-coupled repair in a mismatch repair mutant background. DNA damage that blocks the transcription of genes is prioritized for repair by transcription-coupled DNA repair pathways. RNA polymerases stalled at DNA lesions obstruct repair enzymes, but this situation is turned to the advantage of the cell by transcription-repair coupling factors that remove the stalled RNA polymerase from DNA and increase the rate at which the lesion is repaired. Recent structural studies of the bacterial transcription-repair coupling factor, Mfd, have revealed a modular architecture in which an ATP-dependent DNA-based motor is coupled to protein-protein interaction domains that can attach the motor to RNA polymerase and the DNA repair protein UvrA. Here I review the key features of this multifunctional protein and discuss how recent mechanistic and structural findings have advanced our understanding of transcription-coupled DNA repair in bacteria. |
349 | What is the association between Generalized anxiety disorder and mortality risk? | Numerous studies have demonstrated that Generalized anxiety disorder is associated with increased mortality risk in different populations, including veterans and non demented elderly individuals. Anxiety disorders predict greater mortality, particularly when present with other psychiatric disorders. However, one study has found that generalized anxiety disorder was not associated with excess mortality in depressive elderly people. | [23929442, 12490824, 12063146, 12947243, 9133488, 16998780, 22549369, 19321850, 17450651, 1474300, 11769822] | 456 | BACKGROUND: There are conflicting data on the role of anxiety in predicting mortality. AIMS: To evaluate the 10-year mortality risk associated with anxiety in community-dwelling elderly people. METHOD: Using data from 718 men and 1046 women aged 65 years and over, gender-stratified associations of anxiety symptoms (Spielberger State-Trait Anxiety Inventory, third tertile) and current DSM-IV anxiety disorder including generalised anxiety disorder (GAD) and phobia with all-cause and cardiovascular mortality were determined. RESULTS: In women, mortality risk was increased for anxiety disorder and GAD in multivariate Cox models (hazard ratio (HR) = 1.53, 95% CI 1.02-2.27 and HR = 2.04, 95% CI 1.08-3.86 respectively), whereas for phobia it was nearly significant (HR = 1.52, 95% CI 0.94-2.47). Anxiety trait symptoms became non-significant as a result of the confounding effect of depressive symptoms. Anxiety disorder was associated with cardiovascular mortality in univariate analysis (HR = 2.42, 95% CI 1.16-5.07). No significant associations were found in men. CONCLUSIONS: Our study suggests a gender-specific association of anxiety and mortality. Anxiety disorders are prevalent and associated with increased morbidity and mortality. Some chronic anxiety disorders, including generalized anxiety disorder (GAD), may be characterized by an underlying high level of anxiety on which exacerbations of symptoms are superimposed. Effective treatment of anxiety disorders should therefore strive to attain both an acute reduction in the symptoms of anxiety (a response) and sustained resolution of the symptoms of any underlying chronic anxiety (remission). This strategy may necessitate long-term treatment of these disorders by pharmacotherapy and/or psychotherapy. Studies using the serotonin and norepinephrine reuptake inhibitor (SNRI), venlafaxine extended release (XR), suggest that these aims may be achieved using this newer class of drugs. Studies with venlafaxine XR in patients with GAD have demonstrated robust anxiolytic efficacy over placebo, particularly regarding worry, cognitive dysfunction, and muscular tension, which are specific to GAD. Administration of venlafaxine XR over both short- (8-week) and long-term (6-month) periods resulted in a significantly greater number of patients achieving response and remission than obtained with placebo. Long-term treatment with venlafaxine XR in patients with GAD showed greater efficacy than that observed in short-term studies. This was achieved without any loss of short-term efficacy and patients' social functioning was also restored. While available data indicate that venlafaxine XR is an appropriate choice of agent in the long-term treatment of GAD, more studies are needed to determine how to further increase remission rates and to maintain remission beyond 6 months. BACKGROUND: Previous reports of suicide risk in patients with anxiety disorders have been inconsistent. METHODS: Using the FDA database, we assessed suicide and suicide attempt risk among patients, participating in recent clinical trials evaluating new anti-anxiety medications, with diagnosis of panic disorder (PD), social anxiety disorder or social phobia (SP), generalized anxiety disorder (GAD), post traumatic stress disorder (PTSD), and obsessive compulsive disorder (OCD). RESULTS: Overall, among 20076 participating anxious patients, 12 committed suicide and 28 attempted suicide. The annual suicide risk rate was 193/100000 patients and annual suicide attempt risk was 1350/100000 patients. LIMITATIONS: Clinical trial data have limited applicability to clinical practice. Participants in clinical trials are a highly selected, nonrepresentative sample of the clinical population. A number of patients never complete clinical trials and thus data are based on a limited sub-sample. These trials were not primarily designed to assess suicide risk. CONCLUSIONS: Suicide risk in patients with anxiety disorders is higher than previously thought. Patients with anxiety disorders warrant explicit evaluation for suicide risk. Anxiety disorders, which include generalized anxiety disorder, panic disorder, posttraumatic stress disorder, obsessive-compulsive disorder, and phobic disorders, are the psychiatric disorders most commonly found in the community, according to the results of recent epidemiologic studies. However, failure to diagnose these disorders occurs in up to 50% of patients with an anxiety disorder. This failure to correctly diagnose and appropriately treat anxiety disorders can result in overutilization of health care services and increased morbidity and mortality rates from either the anxiety disorder or comorbid medical conditions. Reliable diagnostic tools to improve the early recognition of anxiety disorders can subsequently result in more effective treatment. BACKGROUND: The association between depression and an increased risk of death in elderly persons has been established in both clinical and community studies. Co-occurrence of depression and generalized anxiety has been shown to represent more severe and more chronic psychopathology. However, little is known about the relation between generalized anxiety disorder, mixed anxiety-depression (generalized anxiety disorder and depression) and excess mortality in the elderly. OBJECTIVE: To investigate whether generalized anxiety and mixed anxiety-depression are associated with mortality. METHOD: Generalized anxiety disorder, mixed anxiety-depression and depression were assessed in 4051 older persons with a ten-year follow-up of community death registers. The mortality risk of generalized anxiety, depression and mixed anxiety-depression was calculated after adjustment for demographic variables, physical illness, functional disabilities and social vulnerability. RESULTS: In generalized anxiety disorder and mixed anxiety-depression no significant excess mortality was found. In depression a significant excess mortality was found in men [HR 1.44 (1.09-1.89)] but not in women [HR 1.04 (0.87-1.24)] after adjustment for the different variables. CONCLUSIONS: In elderly persons depression increases the risk of death in men. Neither generalized anxiety nor mixed anxiety-depression are associated with excess mortality. Generalized anxiety disorder may even predict less mortality in depressive elderly people. The relation between generalized anxiety disorder and its possibly protective effect on mortality has to be further explored. OBJECTIVE: To examine the 1-month prevalence of generalized anxiety disorder (GAD) according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), Diagnostic and Statistical Manual of Mental, Fifth Edition (DSM-V), and International Classification of Diseases, Tenth Revision (ICD-10), and the overlap between these criteria, in a population sample of 75-year-olds. We also aimed to examine comorbidity between GAD and other psychiatric diagnoses, such as depression. METHOD: During 2005-2006, a comprehensive semistructured psychiatric interview was conducted by trained nurses in a representative population sample of 75-year-olds without dementia in Gothenburg, Sweden (N = 777; 299 men and 478 women). All psychiatric diagnoses were made according to DSM-IV. GAD was also diagnosed according to ICD-10 and DSM-V. RESULTS: The 1-month prevalence of GAD was 4.1% (N = 32) according to DSM-IV, 4.5% (N = 35) according to DSM-V, and 3.7% (N = 29) according to ICD-10. Only 46.9% of those with DSM-IV GAD fulfilled ICD-10 criteria, and only 51.7% and 44.8% of those with ICD-10 GAD fulfilled DSM-IV/V criteria. Instead, 84.4% and 74.3% of those with DSM-IV/V GAD and 89.7% of those with ICD-10 GAD had depression. Also other psychiatric diagnoses were common in those with ICD-10 and DSM-IV GAD. Only a small minority with GAD, irrespective of criteria, had no other comorbid psychiatric disorder. ICD-10 GAD was related to an increased mortality rate. CONCLUSIONS: While GAD was common in 75-year-olds, DSM-IV/V and ICD-10 captured different individuals. Current definitions of GAD may comprise two different expressions of the disease. There was greater congruence between GAD in either classification system and depression than between DSM-IV/V GAD and ICD-10 GAD, emphasizing the close link between these entities. OBJECTIVE: To examine whether the 1-year prevalence of major depressive disorder (MDD), generalized anxiety disorder (GAD), and their comorbidity were associated with subsequent all-cause and cardiovascular disease (CVD) mortality during 15 years in Vietnam veterans. METHODS: Participants (N = 4256) were from the Vietnam Experience Study. Service, sociodemographic, and health data were collected from service files, telephone interviews, and a medical examination. One-year prevalence of MDD and GAD was determined through a diagnostic interview schedule based on the Diagnostic and Statistical Manual of Mental Disorders (version IV) criteria. Mortality over the subsequent 15 years was gathered from US army records. RESULTS: MDD and GAD were positively and significantly associated with all-cause and CVD mortality. The relationships between MDD and GAD and CVD mortality were no longer significant after adjustment for sociodemograhics, health status at entry, health behaviors, and other risk markers. Income was the covariate with the strongest impact on this association. In analyses comparing comorbidity and GAD and MDD alone, with neither diagnosis, comorbidity proved to be the strongest predictor of both all-cause and CVD mortality. CONCLUSION: GAD and MDD predict all-cause mortality in a veteran population after adjusting for a range of covariates. However, those with both GAD and MDD were at greatest risk of subsequent death, and it would seem that these disorders may interact synergistically to affect mortality. Future research on mental disorders and health outcomes, as well as future clinical interventions, should pay more attention to comorbidity. Anxiety disorders are prevalent and associated with an increase in morbidity and mortality, particularly when present with additional psychiatric disorders. They represent a public health and economic burden, yet they are commonly underrecognized and undertreated. Benzodiazepines are effective anxiolytics, but they primarily treat the somatic symptoms of generalized anxiety disorder (GAD), and are not effective in treating the depressive symptoms that are often comorbid in chronic anxiety disorders like GAD. Some antidepressants may therefore offer the best choice of therapy. Their benefit in the treatment of GAD has been demonstrated using the tricyclic antidepressant, imipramine, and some selective serotonin reuptake inhibitors. The serotonin and norepinephrine reuptake inhibitor venlafaxine extended release (XR), has been indicated for GAD and has proven to be effective in both the short- and long-term treatment of patients with this disorder. Many patients treated with venlafaxine XR achieve and sustain remission from the symptoms of GAD, which is the goal of treatment. Over the past two decades, anxiety disorders have become the focus of much research after years of relative obscurity. The accumulating data has suggested that anxiety disorders may have many consequences including decreased quality of life, economic dependence, multiple somatic complaints, maladaptive personality traits, and increased mortality due to suicide, cardiovascular, and cerebrovascular causes. Aggressive management of these disorders may greatly lessen the impact. |
350 | Which molecule is targeted by a monoclonal antibody Mepolizumab? | Mepolizumab is a humanized monoclonal antibody that binds to and inactivates interleukin-5 that has been shown to reduce asthma exacerbations in patients with severe eosinophilic asthma. | [14699394, 21346698, 16184589, 24685200, 18298130, 22998420, 14523040, 23544105, 22092535, 12870444, 20810155, 19264686, 19264687, 12406833, 11496242, 22541618, 16931891, 24322486, 21348536, 21958585, 15813818, 19929788, 23844029, 23742015, 21824072, 21790283, 21443279, 25199059, 25199060, 23257685, 16462679, 12704348, 20021987, 20110057, 17872493, 24424174, 20565230, 20513524, 19243381, 19828470, 15175031, 18344568, 23362812, 22901886] | 457 | BACKGROUND: IL-5 is a cytokine critically involved in regulating several aspects of eosinophils including their production, activation, and tissue recruitment. As such, IL-5 may be involved in the pathogenesis of hypereosinophilic syndromes, a group of poorly treated diverse disorders characterized by sustained peripheral blood and/or tissue eosinophilia. OBJECTIVE: We aimed to assess the safety and efficacy of a humanized blocking monoclonal antibody against IL-5 (mepolizumab) in patients with several forms of hyper-eosinophilic syndromes. METHODS: We performed an open-label trial of anti-IL-5 in which 3 intravenous doses (10 mg/kg, maximum 750 mg) were administered at 4-week intervals to 4 patients with hypereosinophilic syndromes (defined by peripheral blood and/or tissue eosinophilia). The effects of treatment on safety, eosinophil levels (in peripheral blood and/or diseased tissue), pulmonary function, and quality of life were measured over a 28-week period. RESULTS: Anti-IL-5 was well tolerated in all patients and lowered peripheral blood eosinophil counts despite ongoing systemic glucocorticoid therapy. The decline in circulating eosinophil counts was sustained for at least 12 weeks after the last dose of anti-IL-5. In addition, anti-IL-5 improved clinical and quality of life measurements. In one patient with striking tissue eosinophilia (eosinophilic esophagitis), anti-IL-5 resulted in a 10-fold reduction in tissue eosinophil levels. CONCLUSIONS: These results suggest that anti-IL-5 is safe, effective in lowering eosinophil levels, and has potential glucocorticoid-sparing effects in patients with a variety of hyper-eosinophilic syndromes. As such, anti-IL-5 may have significant therapeutic potential for hypereosinophilic syndromes. Hypereosinophilic syndrome (HES) is a rare disorder that is characterized by persistent and marked eosinophilia combined with organ system dysfunction. HES has substantial clinical heterogeneity but can be fatal without treatment, especially in patients who present with a myelodysplastic variant of the disorder. Although the pathophysiology of HES is poorly defined, dysregulation of cytokines (interleukin 5 [IL-5], IL-3, granulocyte-macrophage colony-stimulating factor [GM-CSF]) responsible for the maturation of eosinophils is a primary feature. Of these cytokines, IL-5 appears to have the greatest role in the regulation of eosinophil maturation. There is no Food and Drug Administration-approved treatment for HES as yet; current strategies are designed to lower blood eosinophils and attempt to limit end-organ damage. Historically, corticosteroids and cytotoxic agents have been the mainstays of therapy, with biological response modifiers such as interferon-alpha also effective in some patients. However, despite improvements in survival, available agents have significant limitations in terms of efficacy, tolerability, and long-term toxicity. More recently, new agents directed at specific targets in the pathogenesis of HES have been developed. These include imatinib mesylate, a tyrosine kinase inhibitor, and more recently, mepolizumab, an anti-IL-5 monoclonal antibody. In a small case series of patients, these agents have been shown to produce hematological and clinical responses in patients with HES, although they may be effective in different subsets of patients. These targeted therapies have the potential to improve clinical outcomes and to further the understanding the pathophysiology of this difficult-to-treat condition. Despite the administration of appropriate treatment, a high number of patients with asthma remain uncontrolled. This suggests the need for alternative treatments that are effective, safe and selective for the established asthma phenotypes, especially in patients with uncontrolled severe asthma. The most promising options among the new asthma treatments in development are biological therapies, particularly those monoclonal antibodies directed at selective targets. It should be noted that the different drugs, and especially the new biologics, act on very specific pathogenic pathways. Therefore, determination of the individual profile of predominant pathophysiological alterations of each patient will be increasingly important for prescribing the most appropriate treatment in each case. The treatment of severe allergic asthma with anti-IgE monoclonal antibody (omalizumab) has been shown to be effective in a large number of patients, and new anti-IgE antibodies with improved pharmacodynamic properties are being investigated. Among developing therapies, biologics designed to block certain pro-inflammatory cytokines, such as IL-5 (mepolizumab) and IL-13 (lebrikizumab), have a greater chance of being used in the clinic. Perhaps blocking more than one cytokine pathway (such as IL-4 and IL-13 with dulipumab) might confer increased efficacy of treatment, along with acceptable safety. Stratification of asthma based on the predominant pathogenic mechanisms of each patient (phenoendotypes) is slowly, but probably irreversibly, emerging as a tailored medical approach to asthma, and is becoming a key factor in the development of drugs for this complex respiratory syndrome. Mepolizumab is an anti-interleukin-5 monoclonal antibody that is in clinical trials with GlaxoSmithKline (GSK) for the treatment of severe asthma, nasal polyposis and hypereosinophilic syndrome and eosinophilic oesophagitis (the latter two indications are classed as eosinophilia in the phase table). Interleukin-5 stimulates the production, activation and maturation of eosinophils. Since mepolizumab inhibits interleukin-5 and has a long terminal half-life, treatment with mepolizumab causes a sustained reduction in the numbers of circulating eosinophils. Thus, mepolizumab may be a useful therapeutic agent for the treatment of conditions characterized by increased levels of eosinophils. Hypereosinophilic syndrome is a rare idiopathic disease with broad clinical signs and symptoms that is diagnosed based on a persistent blood eosinophil count of >1500 cells, various end-organ damages (including skin, heart, lung, nervous system and digestive system), and with exclusion of known secondary causes of hypereosinophilia. Mepolizumab is in clinical trials for the treatment of hypereosinophilic syndrome, eosinophilc oesophagitis, severe asthma (in patients with airway eosinophilia) and nasal polyposis. GlaxoSmithKline (GSK) has completed enrolment in a phase II study of mepolizumab in 20 patients with symptomatic eosinophilic bronchitis with or without asthma in Canada. The randomized, double-blind, placebo-controlled study is evaluating the effects of intravenous mepolizumab on asthma control, airway eosinophilia and the degree to which concomitant corticosteroid treatment can be reduced (NCT00292877). In previous clinical studies, including trials in the EU and US, mepolizumab has shown a lack of effect on allergen-induced airway responses and inflammation despite a significant reduction in blood and sputum eosinophil levels.A randomized, double-blind, placebo-controlled, multicentre, phase III study of mepolizumab over 9 months in 85 patients with hypereosinophilic syndrome was completed in 2006. All patients have been offered, and continued in, a phase III, open-label, long-term extension study of mepolizumab. Enrolment in this study was completed in September 2006.A phase III, compassionate use trial of mepalizumab (NCT00244686) in patients with hypereosinophilic syndrome was ongoing in October 2007 in the US. Patients who have significant clinical disease but are unresponsive to traditional treatment and those who have demonstrated clinical benefit from previous anti-IL-5 treatment are eligible to take part in the trial. Mepolizumab received orphan drug status for first-line treatment in patients with hypereosinophilic syndrome in the US and the EU in 2004. Mepolizumab is also in phase I/II clinical development for the treatment of eosinophilic oesophagitis. A phase I/II trial (NCT00358449) began in August 2006 in the US, Australia, the UK and Canada, and will enrol approximately 72 paediatric patients with eosinophilic oesophagitis. The randomized, parallel-group clinical trial will evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of intravenous mepolizumab for 12 weeks. In September 2006, GSK completed enrolment in a phase I/II study of mepolizumab for the treatment of eosinophilic oesophagitis in ten adult patients in Switzerland (NCT00274703). The randomized, double-blind, placebo-controlled study will evaluate the pharmacokinetics, pharmacodynamics, safety and tolerability of IV mepolizumab.A phase I/II trial of mepolizumab in four patients with eosinophilic oesophagitis conducted by Cincinnati Children's hospital found the monoclonal antibody was safe and effective. Brigham and Women's Hospital in association with GSK is conducting a phase I/II trial of mepolizumab in patients with Churg-Strauss Syndrome (CSS) in the US. The trial, which started in September 2007, will evaluate the potential of mepolizumab to reduce the need for corticosteroid therapy in patients with CSS (NCT00527566). CSS, otherwise known as allergic granulomatosis, is defined by patients with asthma, eosinophilia and vasculitis. INTRODUCTION: Five percent of asthmatics have severe symptoms despite high doses of inhaled (ICS) or additional oral corticosteroids (OCS): these patients have high morbidity, risk for asthma death, and account for half of asthma healthcare spending. A subgroup (20 - 40%) of these has persistent airway eosinophilia and frequent exacerbations. Mepolizumab is a humanized monoclonal antibody that blocks binding of the key cytokine implicated specifically in eosinophil maturation and survival, interleukin-5, to its receptor. AREAS COVERED: Pharmacology, Phase I/IIa and Phase II/III studies of mepolizumab for asthma. Mepolizumab depleted blood and sputum eosinophils and partially reduced airway and bone marrow eosinophils. It also reduced airway remodeling. In unselected patients with moderate/severe asthma there was no clinically significant effect on lung function, but a trend to reduced exacerbation rates. When patients were selected for persistent sputum eosinophilia despite high-dose ICS/OCS, and frequent exacerbations, mepolizumab reduced exacerbations by 50%. EXPERT OPINION: Mepolizumab can reduce exacerbation rates in the severe asthma cohort who have eosinophilic airway inflammation despite corticosteroid treatment. This may be 30% of severe asthmatics and represents a new and important treatment option. Further studies need to confirm efficacy and indications for asthma (and other eosinophilic airway disease), and to examine clinical consequences of reducing remodeling. BACKGROUND: Interleukin (IL)-5 is believed to be a key cytokine in eosinophil inflammatory infiltration in asthma. Previous clinical trials have evaluated the efficacy and safety of mepolizumab, a monoclonal antibody against IL-5, in patients with asthma. However, most of these studies were small, the conclusions were inconsistent, and the precise effects are therefore debatable. METHODS: A meta-analysis of randomized placebo-controlled trials was conducted to evaluate the effect of intravenous infusion of mepolizumab on clinical outcomes in patients with asthma. Trials were searched in PubMed, Embase, Web of Science, Cochrane CENTRAL, Scopus, reviews, and reference lists of relevant articles. The outcome variables analyzed included eosinophil counts in blood and sputum, airways outcome measures, exacerbations, asthma control, and quality of life scores. RESULTS: Seven studies met final inclusion criteria (total n = 1131). From the pooled analyses, mepolizumab significantly reduced eosinophils in blood (MD -0.29×10(9)/L, 95% CI -0.44 to -0.14×10(9)/L, P = 0.0001) and sputum (MD -6.05%, 95% CI -9.34 to -2.77%, P = 0.0003). Mepolizumab was also associated with significantly decreased exacerbation risk than placebo (OR 0.30, 95%CI 0.13 to 0.67, P = 0.004), and with a significant improvement in the scores on the Asthma Quality of Life Questionnaire (AQLQ) (MD 0.26, 95% CI 0.03 to 0.49, P = 0.03) in patients with eosinophilic asthma. There were no statistical differences between the groups with respect to FEV1, PEF, or histamine PC20 (all P>0.05), and a non-significant trend for improvement in scores on the Juniper Asthma Control Questionnaire (JACQ) (MD -0.21, 95% CI -0.43 to 0.01, P = 0.06) in the mepolizumab group was observed. CONCLUSIONS: Mepolizumab reduces the risk of exacerbations and improves quality of life in patients with eosinophilic asthma, but no significant improvement in lung function outcomes was observed. Further research is required to establish the possible role of anti-IL-5 as a therapy for asthma. Interleukin-5 is a Th2 homodimeric cytokine involved in the differentiation, maturation, migration, development, survival, trafficking and effector function of blood and local tissue eosinophils, in addition to basophils and mast cells. The IL-5 receptor (IL-5R) consists of an IL-5-specific α subunit that interacts in conformationally dynamic ways with the receptor's βc subunit, an aggregate of domains it shares with binding sites of IL-3 and granulocyte-macrophage colony-stimulating factor. IL-5 and IL-5R drive allergic and inflammatory immune responses characterizing numerous diseases, such as asthma, atopic dermatitis, chronic obstructive pulmonary disease, eosinophilic gastrointestinal diseases, hyper-eosinophilic syndrome, Churg-Strauss syndrome and eosinophilic nasal polyposis. Although corticosteroid therapy is the primary treatment for these diseases, a substantial number of patients exhibit incomplete responses and suffer side-effects. Two monoclonal antibodies have been designed to neutralize IL-5 (mepolizumab and reslizumab). Both antibodies have demonstrated the ability to reduce blood and tissue eosinophil counts. One additional monoclonal antibody, benralizumab (MEDI-563), has been developed to target IL-5R and attenuate eosinophilia through antibody-dependent cellular cytotoxicity. All three monoclonal antibodies are being clinically evaluated. Antisense oligonucleotide technology targeting the common βc IL-5R subunit is also being used therapeutically to inhibit IL-5-mediated effects (TPI ASM8). Small interfering RNA technology has also been used therapeutically to inhibit the expression of IL-5 in animal models. This review summarizes the structural interactions between IL-5 and IL-5R and the functional consequences of such interactions, and describes the pre-clinical and clinical evidence supporting IL-5R as a therapeutic target. GlaxoSmithKline (formerly SmithKline Beecham) is developing mepolizumab (SB-240563), a monoclonal antibody directed against IL-5, as a potential treatment for asthma and atopic dermatitis. Phase II trials in asthma were underway by April 1998 and by March 2002, phase II trials had also been initiated in atopic dermatitis. The role of eosinophils as effector cells in asthma pathogenesis has been questioned since an anti-interleukin (IL)-5 monoclonal antibody (mepolizumab), which depleted blood and sputum eosinophils, failed to inhibit allergen-induced bronchoconstriction and airway hyperresponsiveness. However, the effect of IL-5 blockade on tissue eosinophils was not examined. We sought to determine whether mepolizumab depletes airway tissue eosinophils and their products. Twenty-four patients with mild asthma received three intravenous doses of either 750 mg of mepolizumab or placebo in a randomized, double-blind, parallel-group fashion over 20 weeks. Mepolizumab produced a median decrease from baseline of 55% for airway eosinophils (interquartile range, 29-89%; p = 0.009 versus placebo), 52% for bone marrow eosinophils (45-76%, p = 0.003), and 100% for blood eosinophils (range, 67-100%, p = 0.02). Mepolizumab had no appreciable effect on bronchial mucosal staining of eosinophil major basic protein. There were no significant changes in clinical measures of asthma (airway hyperresponsiveness, FEV1, and peak flow recordings) between the mepolizumab and placebo-treated groups. Anti-IL-5 treatment reduces but does not deplete airway or bone marrow eosinophils. The role of the eosinophil remains uncertain. Further clinical studies in asthma with more effective antieosinophil strategies are required. BACKGROUND: The atopy patch test (APT) is an in vivo model to study the induction of eczema by inhalant allergens in atopic dermatitis (AD) patients. Mepolizumab is a monoclonal antibody to interleukin-5, which reduces peripheral blood eosinophils. Previously, we reported that mepolizumab treatment did not result in clinical improvement in AD. The current study investigates the effect of mepolizumab therapy on the APT in the same patients. METHODS: Mepolizumab treatment was given at days 0 and 7 in a double-blind placebo-controlled design. The APT was applied at days -2, 0, 14 and 28. Clinical evaluation of each APT was conducted 48 h after application at days 0, 2, 16 and 30. Skin biopsies were taken at days 0, 2 and 16 for eosinophil counts. RESULTS: The mepolizumab-treated group showed no significant reduction in macroscopic outcome of the APT. Tissue eosinophils were reduced in the mepolizumab-treated group at day 16 compared with placebo; however, this was not significant. CONCLUSION: Mepolizumab therapy cannot prevent the eczematous reaction induced by the APT. Furthermore, the influx of tissue eosinophil numbers in the APT is not significantly inhibited after mepolizumab treatment compared with placebo, despite a significant reduction in peripheral blood eosinophils. PURPOSE OF REVIEW: Eosinophils play an important role in the pathogenesis of allergic, infectious and malignant diseases. Over the last decade, new diagnostic tools and treatment modalities have led to the re-evaluation of the existing definition of eosinophilic disorders. This review discusses a recent proposal for new terminology and classification of hypereosinophilia. The results of targeted therapy for hypereosinophilia-related disorders are also summarized. RECENT FINDINGS: A panel of multidisciplinary experts agreed on unifying definitions and criteria of eosinophilia-associated disorders and created a new classification of hypereosinophilia-related conditions based on clinical, haematological and laboratory findings as well as the underlying cause of hypereosinophilia. Recent results of the treatment of idiopathic hypereosinophilic syndrome (HES) with the anti-interleukin 5 monoclonal antibody mepolizumab showed its efficacy and manageable safety profile. The treatment of platelet-derived growth factor alpha (PDGFRA)-positive HES with imatinib demonstrated long-lasting efficacy and low likelihood of drug resistance. SUMMARY: The unifying terminology and definitions should aid physicians caring for patients with hypereosinophilia. Despite much progress, serum biomarkers correlate with disease severity and predict responses to treatment that are needed. There is also a great need for understanding and specific therapy for PDGFRA-negative HES. BACKGROUND: Approximately 85% of nasal polyps (NPs) in white subjects are characterized by prominent eosinophilia. IL-5 is the key driver of eosinophilic differentiation and survival. OBJECTIVE: We sought to investigate the therapeutic potential of inhibiting IL-5 with a humanized mAb as treatment for severe nasal polyposis. METHODS: Thirty patients with severe nasal polyposis (grade 3 or 4 or recurrent after surgery) refractory to corticosteroid therapy were randomized in a double-blind fashion to receive either 2 single intravenous injections (28 days apart) of 750 mg of mepolizumab (n = 20) or placebo (n = 10). Change from baseline in NP score was assessed monthly until 1 month after the last dose (week 8). Computed tomographic scans were also performed at week 8. RESULTS: Twelve of 20 patients receiving mepolizumab had a significantly improved NP score and computed tomographic scan score compared with 1 of 10 patients receiving placebo at week 8 versus baseline. CONCLUSION: Mepolizumab achieved a statistically significant reduction in NP size for at least 1 month after dosing in 12 of 20 patients. IL-5 inhibition is a potential novel therapeutic approach in patients with severe eosinophilic nasal polyposis. BACKGROUND: Eosinophils may play an important role in the pathogenesis of atopic dermatitis (AD). Interleukin-5 is essential for eosinophil growth, differentiation and migration. A monoclonal antibody to human interleukin-5 (mepolizumab) was developed for atopic diseases. This study was designed to study the effect of mepolizumab in AD. METHODS: Two single doses of 750 mg mepolizumab, given 1 week apart, were studied in patients with moderate to severe AD using a randomized, placebo-controlled parallel group design. The primary endpoint of 'success' to treatment was defined as the percentage of patients with at least 'marked improvement' after 2 weeks as assessed by the Physician's Global Assessment of Improvement (PGA). Furthermore, SCORing AD (SCORAD), pruritus scoring, number of blood eosinophils and serum thymus and activation-regulated chemokine (TARC) values served as secondary endpoints. Fluticasone propionate cream 0.05%, once daily could be used as rescue medication from day 16 if no improvement was recorded. RESULTS: Eighteen patients received mepolizumab and 22 placebo treatment. Peripheral blood eosinophil numbers were significantly reduced in the treatment group compared with placebo (P < 0.05). No clinical success was reached by PGA assessment (P = 0.115), SCORAD (P = 0.293), pruritus scoring and TARC values in the mepolizumab-treated group compared with placebo. However, modest improvement (<50% improvement) assessed by PGA was scored significantly more in the mepolizumab-treated group compared with placebo (P < 0.05). CONCLUSION: Two single doses of 750 mg mepolizumab did not result in clinical success in patients with AD, despite a significant decrease in peripheral blood eosinophils. Eosinophils are major pro-inflammatory cells that make a major contribution to diseases that affect the upper and lower airways, skin and gastrointestinal tract. Interleukin (IL)-5 is central to their maturation and release from the bone marrow together with their subsequent accumulation and activation in the tissues. Mepolizumab is a humanized monoclonal antibody (mAb) with potent IL-5 neutralizing effects that represents a potential treatment for eosinophilic diseases. Several clinical trials with mepolizumab reported that treatment of patients with mild to severe asthma resulted in a substantial reduction in blood and sputum eosinophil numbers. However, clinical outcomes were disappointing as there were no significant effects on airway hyper-reactivity or the late asthmatic reaction to inhaled allergen challenge. More recently two studies, one in in patients with refractory eosinophilic asthma with a history of recurrent severe exacerbations and the other in patients with persistent sputum eosinophilia and symptoms despite systemic treatment with prednisone treatment, reported that monthly intravenous mepolizumab reduced sputum/blood eosinophilia, asthma exacerbations together with improvments in quality of life. Mepolizumab also appears to be an effective therapy for hypereosinophilic syndrome while other trials have shown efficacy of mepolizumab therapy in eosinophilic esophagitis. This review will consider the current status of the clinical development of mepolizumab for diseases with a significant eosinophilic component to their pathology. Several lines of evidence suggest that deficiency of eosinophils is not associated with any characteristic abnormality. Patients lacking eosinophils, in the setting of immunodeficiency or as a consequence of IgG-mediated eosinophil precursor destruction, do not display any distinguishing abnormalities related to eosinophil reduction. The observation that eosinophil-deficient mice do not display any distinctive syndrome or failure of their health is evidence that, under ordinary laboratory conditions, the eosinophil does not play a critical role in the well-being of mammals. Observations that monoclonal antibodies to interleukin-5 (IL-5) are well tolerated appear unsurprising in light of these findings. For example, patients with the hypereosinophilic syndrome have received mepolizumab, an anti-IL-5 monoclonal antibody, for as long as 6 years and have not developed any characteristic set of adverse events. Safety data for reslizumab, another anti-IL-5 monoclonal antibody, and benralizumab, a monoclonal antibody to the IL-5 receptor α-chain, are comparatively limited, especially for benralizumab, although reports of administration of these antibodies to humans suggest that they are well tolerated. Thus, data to the present suggest that reduction of eosinophils appears to have no characteristic ill effects on normal health, and monoclonal antibodies that deplete eosinophils have the potential to be widely employed in the treatment of eosinophil-associated diseases. Peripheral blood eosinophilia and eosinophilic lung inflammation are common in a variety of pulmonary conditions, including eosinophilic pneumonia and asthma, hypereosinophilic syndrome and Churg-Strauss syndrome. Therapy in most of these clinical entities consists of long-term treatment with systemic corticosteroids, which is not always successful and has substantial side-effects. Interest has increased considerably regarding alternative corticosteroid-sparing "smart" regimens in these diseases that target IL-5, an important regulator of eosinophilic development and function. To date, two humanized monoclonal antibodies, mepolizumab and reslizumab, have been developed that bind to human IL-5. In addition a new monoclonal antibody (MEDI-563) has been recently developed targeting the IL-5 receptor. This review will investigate the current status on IL-5 targeted therapy and related patents regarding eosinophil-driven respiratory diseases, primarily eosinophilic asthma but also CSS and HES. Recent advances and information from clinical trials will be presented in a way that will allow the reader to approach the role of the eosinophil in the lung diseases presented in this review. Mepolizumab (Bosatria(®), GlaxoSmithKline) is a biologic agent developed to treat asthma. It represents a humanized monoclonal antibody of IgG1 κ type, which targets human IL-5 and thus prevents its interaction with the α-chain of the IL-5 receptor. To date, it has not been approved for use in any eosinophil-related disorder; however, several studies have suggested some therapeutic benefit across a spectrum of eosinophil-related disorders. This article evaluates the currently available preclinical and clinical studies, and the impact of mepolizumab against a variety of eosinophilic disorders. Eosinophilic oesophagitis (EE) is a clinico-pathological entity recognized with increased frequency in children and adults. It is an atopic disease involving ingested and inhaled allergens. A pathological eosinophilic infiltrate is diagnosed by finding ≥ 15 eosinophils per high-powered field on oesophageal mucosal biopsies. This infiltrate may result in a narrowed oesophageal lumen. It does not involve the stomach or duodenum. Children commonly present with abdominal pain, vomiting and dysphagia. Presentation in adults is with dysphagia, heartburn, chest pain or impaction of a food bolus in the oesophagus. There is often a history of allergy (asthma, hay fever, eczema). A male predominance (70% in adults) is unexplained. Distinctive endoscopic features are linear furrows, mucosal rings and white papules, and the narrowed lumen may be appreciated. Although EE and gastro-oesophageal reflux disease are separate entities, there is a significant overlap of the conditions. Treatment options include nonpharmacological approaches including an elimination or elemental diet, and/ or medications, chiefly with corticosteroids. The topical administration of fluticasone propionate has been demonstrated to improve symptoms and mobilize the pathological infiltrate of eosinophils. There has been a variable effect with the leukotriene receptor antagonist montelukast and promising early results with mepolizumab, a monoclonal antibody against interleukin-5. The long-term efficacy of topical corticosteroids has not been well studied and most patients experience recurrent symptoms when treatment is completed. Currently, repeated short courses of topical corticosteroids are utilized. Acid suppression by a proton pump inhibitor may be considered in view of the overlap between EE and gastro-oesophageal reflux disease. BACKGROUND: Some patients with severe asthma have frequent exacerbations associated with persistent eosinophilic inflammation despite continuous treatment with high-dose inhaled glucocorticoids with or without oral glucocorticoids. METHODS: In this randomized, double-blind, double-dummy study, we assigned 576 patients with recurrent asthma exacerbations and evidence of eosinophilic inflammation despite high doses of inhaled glucocorticoids to one of three study groups. Patients were assigned to receive mepolizumab, a humanized monoclonal antibody against interleukin-5, which was administered as either a 75-mg intravenous dose or a 100-mg subcutaneous dose, or placebo every 4 weeks for 32 weeks. The primary outcome was the rate of exacerbations. Other outcomes included the forced expiratory volume in 1 second (FEV1) and scores on the St. George's Respiratory Questionnaire (SGRQ) and the 5-item Asthma Control Questionnaire (ACQ-5). Safety was also assessed. RESULTS: The rate of exacerbations was reduced by 47% (95% confidence interval [CI], 29 to 61) among patients receiving intravenous mepolizumab and by 53% (95% CI, 37 to 65) among those receiving subcutaneous mepolizumab, as compared with those receiving placebo (P<0.001 for both comparisons). Exacerbations necessitating an emergency department visit or hospitalization were reduced by 32% in the group receiving intravenous mepolizumab and by 61% in the group receiving subcutaneous mepolizumab. At week 32, the mean increase from baseline in FEV1 was 100 ml greater in patients receiving intravenous mepolizumab than in those receiving placebo (P=0.02) and 98 ml greater in patients receiving subcutaneous mepolizumab than in those receiving placebo (P=0.03). The improvement from baseline in the SGRQ score was 6.4 points and 7.0 points greater in the intravenous and subcutaneous mepolizumab groups, respectively, than in the placebo group (minimal clinically important change, 4 points), and the improvement in the ACQ-5 score was 0.42 points and 0.44 points greater in the two mepolizumab groups, respectively, than in the placebo group (minimal clinically important change, 0.5 points) (P<0.001 for all comparisons). The safety profile of mepolizumab was similar to that of placebo. CONCLUSIONS: Mepolizumab administered either intravenously or subcutaneously significantly reduced asthma exacerbations and was associated with improvements in markers of asthma control. (Funded by GlaxoSmithKline; MENSA ClinicalTrials.gov number, NCT01691521.). BACKGROUND: Many patients with severe asthma require regular treatment with oral glucocorticoids despite the use of high-dose inhaled therapy. However, the regular use of systemic glucocorticoids can result in serious and often irreversible adverse effects. Mepolizumab, a humanized monoclonal antibody that binds to and inactivates interleukin-5, has been shown to reduce asthma exacerbations in patients with severe eosinophilic asthma. METHODS: In a randomized, double-blind trial involving 135 patients with severe eosinophilic asthma, we compared the glucocorticoid-sparing effect of mepolizumab (at a dose of 100 mg) with that of placebo administered subcutaneously every 4 weeks for 20 weeks. The primary outcome was the degree of reduction in the glucocorticoid dose (90 to 100% reduction, 75 to less than 90% reduction, 50 to less than 75% reduction, more than 0 to less than 50% reduction, or no decrease in oral glucocorticoid dose, a lack of asthma control during weeks 20 to 24, or withdrawal from treatment). Other outcomes included the rate of asthma exacerbations, asthma control, and safety. RESULTS: The likelihood of a reduction in the glucocorticoid-dose stratum was 2.39 times greater in the mepolizumab group than in the placebo group (95% confidence interval, 1.25 to 4.56; P=0.008). The median percentage reduction from baseline in the glucocorticoid dose was 50% in the mepolizumab group, as compared with no reduction in the placebo group (P=0.007). Despite receiving a reduced glucocorticoid dose, patients in the mepolizumab group, as compared with those in the placebo group, had a relative reduction of 32% in the annualized rate of exacerbations (1.44 vs. 2.12, P=0.04) and a reduction of 0.52 points with respect to asthma symptoms (P=0.004), as measured on the Asthma Control Questionnaire 5 (in which the minimal clinically important difference is 0.5 points). The safety profile of mepolizumab was similar to that of placebo. CONCLUSIONS: In patients requiring daily oral glucocorticoid therapy to maintain asthma control, mepolizumab had a significant glucocorticoid-sparing effect, reduced exacerbations, and improved control of asthma symptoms. (Funded by GlaxoSmithKline; SIRIUS ClinicalTrials.gov number, NCT01691508.). BACKGROUND: We examined levels of hyaluronan, a matrix glycosaminoglycan and versican, a matrix proteoglycan, in the sputum of asthmatics treated with mepolizumab (anti-IL-5 monoclonal antibody) versus placebo to evaluate the utility of these measurements as possible biomarkers of asthma control and airway remodeling. METHODS: Patients with severe, prednisone-dependent asthma received either mepolizumab or placebo as described in a previously published randomized, double-blind, placebo-controlled study. We measured hyaluronan and versican levels by enzyme-linked immunosorbent assay in sputum collected before and after the 16-week treatment phase. Patients underwent a predefined prednisone tapering schedule if they remained exacerbation free, and sputum eosinophil percentage, asthma control questionnaire (ACQ) and spirometry were monitored. RESULTS: After 6 months of mepolizumab therapy and prednisone tapering, there was a significant increase in sputum hyaluronan in the placebo group compared with baseline (p = 0.003). In contrast, there was a significant decrease in sputum hyaluronan in the active treatment group compared with placebo (p = 0.007), which correlated with improvements in percent forced expiratory volume in 1 s (FEV1%) (p = 0.001) and ACQ scores (p = 0.009) as well as a decrease in sputum eosinophils (p = 0.02). There was a nonsignificant increase in sputum versican in the placebo group (p = 0.16), a decrease in the mepolizumab group (p = 0.13) and a significant inverse correlation between versican reduction and FEV1% improvement (p = 0.03). CONCLUSIONS: Sputum hyaluronan values are reduced with mepolizumab therapy and correlate with improved clinical and spirometry values, suggesting this measurement may serve as a noninvasive biomarker of asthma control. Diagnosis of major hypereosinophilia (>1500 x 10(9)/L) is complex because the possible causes cover the entire range of medical specialties. History and clinical condition will usually suggest parasitic or allergic diseases or drug reactions. When workups for them are negative, rarer causes must be suspected: specific organ diseases (chronic eosinophilic pneumonia, bullous pemphigoid, etc.), solid tumor, clonal blood disorders, or vasculitis. When the condition is prolonged and unexplained, hypereosinophilic syndrome is diagnosed. A rare disorder, its prognosis depends on largely on its cardiac effects. It is usually associated with heterogeneous hematologic conditions, mainly myeloproliferative and lymphocytic disease. The myeloproliferative or primary variant sometimes follows chromosomal deletions that cause a fusion between the Fip1-like1 (FIP1L1) and platelet-derived growth factor receptor (PDGFR) genes, thus increasing the tyrosine kinase activity of the latter. Imatinib mesylate, a tyrosine kinase inhibitor, is usually effective in this situation. In the lymphocytic variant, hypereosinophilia is secondary to a primitive Th2 lymphocyte expansion that causes overproduction of interleukin 5 (IL-5). Corticosteroids are the first-line therapy. Mepolizumab, an anti-IL-5 monoclonal antibody, currently being evaluated, seems promising. Despite recent progress, about 40% of the cases of hypereosinophilic syndrome remain unexplained. Among diagnostic progress over the last three years in internal medicine, Antisynthetase Syndrome is now more easily recognised with the diffusion of laboratory tests for research of antibodies against tRNA synthetases (Anti JO1, anti PL7, Anti PL12). In two third of cases, these antibodies are found despite absence of antinuclear antibodies. Hence, we have to search them specifically in patients with polyarthritis associated with myositis, cutaneous manifestations (Raynaud phenomenom and "mechanic'hands") and interstitial lung disease. Discovery of asymptomatic mutation in the L ferritin coding sequence help us to better understand the "unexplained" hyperferritinemia. Initially described by japonese gastroenterologists, auto immune pancreatitis in fact a part of a systemic sclerosing disease with a biochemical hallmark: in crease of a subclass of immunoglobulins G (IgG4). A new pediatric disease due to a deficiency of the interleukin1 receptor antagonist (multifocal aseptic osteitis, periostitis, stomatitis, disseminated pustulosis) help us to better understand unexplained auto inflammatory diseases. The therapeutic progress is primarily due to an explosion of biological therapies, particularly four of them very useful for internists (in an off label use) : Interleukin 1 inhibitors (anakinra, Canakinumab) to treat some auto inflammatory diseases (cryopirin associated periodic syndromes and deficency of interleukin 1 receptor antagonist), monoclonal antibody against interleukin 5 (mepolizumab) to treat some hypereosinophilic syndromes and Churg and Strauss angiitis, interleukin 6 inhibitiors to treat multifocal Castleman's disease and adult Still disease, a monoclonal antibody against vascular endothelial growth factor (Bevacizumab) to treat hereditary hemorrhagic telangiectasia. RATIONALE: Accumulation of eosinophils in the bronchial mucosa of individuals with asthma is considered to be a central event in the pathogenesis of asthma. In animal models, airway eosinophil recruitment and airway hyperresponsiveness in response to allergen challenge are reduced by specific targeting of interleukin-5. A previous small dose-finding study found that mepolizumab, a humanized anti-interleukin-5 monoclonal antibody, had no effect on allergen challenge in humans. OBJECTIVES: To investigate the effect of three intravenous infusions of mepolizumab, 250 or 750 mg at monthly intervals, on clinical outcome measures in 362 patients with asthma experiencing persistent symptoms despite inhaled corticosteroid therapy (400-1,000 mug of beclomethasone or equivalent). METHODS: Multicenter, randomized, double-blind, placebo-controlled study. MEASUREMENTS AND MAIN RESULTS: Morning peak expiratory flow, forced expiratory volume in 1 second, daily beta(2)-agonist use, symptom scores, exacerbation rates, and quality of life measures. Sputum eosinophil levels were also measured in a subgroup of 37 individuals. Mepolizumab was associated with a significant reduction in blood and sputum eosinophils in both treatment groups (blood, P < 0.001 for both doses; sputum, P = 0.006 for 250 mg and P = 0.004 for 750 mg). There were no statistically significant changes in any of the clinical end points measured. There was a nonsignificant trend for decrease in exacerbation rates in the mepolizumab 750-mg treatment group (P = 0.065). CONCLUSIONS: Mepolizumab treatment does not appear to add significant clinical benefit in patients with asthma with persistent symptoms despite inhaled corticosteroid therapy. Further studies are needed to investigate the effect of mepolizumab on exacerbation rates, using protocols specifically tailored to patients with asthma with persistent airway eosinophilia. Eosinophilia-associated myopathies are clinically and pathologically heterogeneous conditions characterized by the presence of peripheral and/or muscle eosinophilia. There are at least three distinct subtypes: focal eosinophilic myositis, eosinophilic polymyositis, and eosinophilic perimyositis. Infiltrating eosinophils are not always identified in conventional muscle histologic examination, but the eosinophil major basic protein, whose extracellular diffusion is considered a hallmark of eosinophilic cytotoxicity, is usually detected by immunostaining in muscle biopsy. Whereas focal eosinophilic myositis seems to be a benign and isolated condition, and perimyositis is usually related with the inflammatory infiltrate due to fasciitis, eosinophilic polymyositis can be associated with muscular dystrophy or be a feature of multiorgan hypereosinophilic syndrome. Muscle biopsy remains the cornerstone for the diagnosis. Parasitic infections, connective tissue disorders, hematologic and non-hematologic malignancies, drugs, and toxic substances are the main etiologic agents of eosinophilia-associated myopathy. However, in some cases, no known etiologic factor is identified, and these are considered idiopathic. Glucocorticoids are the mainstay therapy in idiopathic forms. Imatinib and mepolizumab, a humanized anti-interleukin 5 monoclonal antibody, may be useful in patients with eosinophilic myositis as part of a hypereosinophilic syndrome. BACKGROUND: Treatments for Churg-Strauss syndrome (CSS), a rare eosinophilic vasculitis characterized by asthma, sinusitis, peripheral eosinophilia, pulmonary infiltrates, and tissue infiltration, are limited by toxicity or poor efficacy. Levels of IL-5, a cytokine regulating eosinophils, can be increased in patients with CSS. Mepolizumab, a humanized monoclonal anti-IL-5 antibody, decreases steroid requirements in patients with non-CSS hypereosinophilic syndromes. OBJECTIVE: The purpose of this study was to assess whether mepolizumab would safely allow corticosteroid tapering in patients with steroid-dependent CSS while decreasing serum markers of disease activity. METHODS: This open-label pilot study treated 7 patients with 4 monthly doses of mepolizumab to assess whether it safely decreased CSS disease activity and permitted tapering of systemic corticosteroids. RESULTS: Mepolizumab was safe and well tolerated in patients with CSS. Mepolizumab reduced eosinophil counts and allowed for safe corticosteroid reduction in all 7 subjects. On cessation of mepolizumab, CSS manifestations recurred, necessitating corticosteroid bursts. CONCLUSION: Mepolizumab is a safe and well-tolerated therapy in patients with CSS, offering clinical benefit by enabling corticosteroid tapering while maintaining clinical stability. OBJECTIVE: Eosinophilic oesophagitis (EoO) is a clinicopathological condition defined by proton pump inhibitor-refractory oesophageal symptoms combined with oesophageal eosinophilia. The pharmacodynamic effect of mepolizumab (a humanised anti-interleukin-5 monoclonal antibody) in EoO was evaluated. METHODS: Eleven adults with active EoO (>20 peak eosinophil number/high power field (hpf) and dysphagia) were randomised to 750 mg of mepolizumab (n = 5) or placebo (n = 6) and received two intravenous infusions, 1 week apart. Those not in complete remission (<5 peak eosinophil number/hpf) after 8 weeks received two further doses 4 weeks apart, 1500 mg of mepolizumab or placebo. The effect of mepolizumab was assessed clinically, endoscopically, histologically, and via blood and tissue biomarkers. RESULTS: As assessed by immunofluorescence, a marked reduction of mean oesophageal eosinophilia (p = 0.03) was seen in the mepolizumab group (-54%) compared with the placebo group (-5%) 4 weeks after initiation of treatment. No further reduction of eosinophil numbers was observed in response to the two additional infusions in either group. Mepolizumab reduced tenascin C (p = 0.033) and transforming growth factor beta1 (p = 0.05) expression in the oesophageal epithelial layer 13 weeks after initiation of treatment. Clinically, limited improvement of symptoms was seen, although a trend was seen between 4 and 13 weeks after initiation of mepolizumab treatment. Mepolizumab was well tolerated. CONCLUSIONS: Mepolizumab significantly reduced eosinophil numbers in oesophageal tissues in adult patients with active EoO, and changes in the expression of molecules associated with oesophageal remodelling were reversed. Minimal clinical improvement was achieved in a subgroup of patients with EoO. Mepolizumab had an acceptable safety profile, even at the high 1500 mg dose level. TRIAL REGISTRATION NUMBER: NCT00274703. In this large (616 patients), double-blind, placebo-controlled, dose-ranging study of mepolizumab (a monoclonal antibody that blocks IL-5 binding to its receptor), patients were given placebo, 75-, 250- or 750-mg mepolizumab by intravenous infusion every 4 weeks for 1 year. Exacerbation rates at all doses were 50% less than those in the placebo group. There were no changes in any other asthma measures (symptoms, quality of life or lung function). This may be a useful advance for a subgroup of severe asthma with frequent exacerbations and persistent eosinophilia, which may be about half of severe asthmatics. More information on patient selection and cost-benefit will be required. |
351 | Which is the major symptom of the Doose syndrome? | Myoclonic astatic epilepsy is the major symptom of the Doose syndrome, which is a difficult to treat idiopathic generalized epilepsy of early childhood. | [21351810, 2115971, 8891396, 22780699, 10768159, 23159713, 8243377, 17105462, 20301494, 24696509, 12073789, 1396420, 21396429, 22266062, 8214350, 23941843, 9184597, 18990309, 20722665, 8753132, 22322415, 19049588, 20472190] | 458 | Among 62 children with myoclonic epilepsy who had first seizures between 1 and 10 years, without clinical or radiological evidence of brain lesion, we selected the 16 patients who had exhibited several types of fits and had stopped having seizures for over two years. First seizures occurred between 18 months and 4 years, and they were generalized clonic, tonic-clonic or tonic. After a mean 3 months' period, patients started also to have absence and myoclonic fits. During the period with various types of seizures, that lasted a mean 10 months, patients were ataxic and hyperkinetic, and 11 of them suffered myoclonic absence status for several hours or days. The EEG showed a high voltage rhythmic slow-wave activity with spikes, differing from the slow spike wave tracing of the Lennox-Gastaut syndrome, and there was no photosensitivity. The mean duration of the epilepsy was 1 year and 4 months and the last seizures were convulsive, occurring mainly during sleep. The clinical and EEG pattern, the high familial incidence are shared by the Doose syndrome, of which the present series seems to be a subgroup, as are other well-defined syndromes: benign and severe myoclonic epilepsies of infancy. One of the most important achievement of contemporary epileptology has been a concept of epileptic syndromes. According to the Commission on Classification and Terminology of the International League Against Epilepsy there are many epileptic syndromes which differ from each other not only by prognosis but also by reaction to pharmacotherapy. Nevertheless the differentation between the some of epileptic syndromes may be difficult in spite of quite precise clinical and electrophysiological criteria. Good example of this problem may be the course of disease of the boy who is now eleven years old. His refractory epilepsy which started 7 years ago shares symptoms and signs of both epilepsy with myoclonic-astatic seizures (Doose Syndrome) and Lennox-Gastaut Syndrome. Felbamate therapy was consider to be the turning-point in both therapeutic and diagnostic meaning. PURPOSE: Myoclonic astatic epilepsy (MAE, Doose syndrome) is a difficult to treat idiopathic generalized epilepsy of early childhood. MAE frequently shows the course of an epileptic encephalopathy and may result in permanent cognitive impairment. Systematic analyses on clinical effects of different AED combinations are still needed. The purpose of our study was to analyze the therapeutic effect of adjunctive lamotrigine (LTG) in pharmacoresistant MAE patients. PATIENTS AND METHODS: In an exploratory, retrospective study, 10 pharmacoresistant MAE patients were included who had been admitted to the Northern German Epilepsy Center between 07/2007 and 12/2010 and had been treated with LTG. Documentation was performed with the electronic seizure diary Epivista. A total observation period of 32 weeks was defined: 8-week 'pre LTG treatment phase' (before starting with LTG), 16-week 'titration phase' (starting with very low LTG doses), 8-week 'follow-up phase'. Seizure frequency, medication and adverse events were extracted from the electronic diary and evaluated in each particular patient. The individual reduction of seizure frequency per day was defined as primary outcome variable. Additionally, a dose-effect-relationship was analyzed for each patient. RESULTS: Six out of ten patients were seizure free during the follow-up phase. Statistical analysis indicated a significant seizure reduction in seven patients at follow-up compared to the pre LTG treatment phase. Seizure frequency did not significantly decrease in two patients and increased in one patient. A significant relationship between seizure frequency per day and LTG dosage during titration and follow-up phase could be demonstrated in nine patients. Group statistics using the exact Wilcoxon test revealed a significant reduction in seizure frequency (p = 0.049, two-sided). CONCLUSION: Our data provide evidence that adjunctive LTG is an eligible therapeutic option for the treatment of pharmacoresistant MAE and encourage further prospective studies to verify this observation. The purpose of this article is to present a short review of the natural history of myoclonic astatic epilepsy (MAE; Doose syndrome) and the Lennox-Gastaut syndrome (LGS). In the 1989 classification of the International League Against Epilepsy (ILAE, 1989), MAE and LGS were initially included in group 2.2: "Cryptogenic or symptomatic generalized epilepsies and syndromes." The subsequent classification of the Proposed Diagnostic Scheme for People with Epileptic Seizures and with Epilepsy (see Ref. 8) placed MAE in axis 3 in the "generalized epilepsy" group and LGS, severe myoclonic epilepsy of infancy (SMEI or Dravet syndrome) and atypical benign partial epilepsy/pseudo-Lennox syndrome (ABPE/PLS) in the "epileptic encephalopathy" group. The semiology of MAE and LGS and their differential diagnosis from SMEI and ABPE/PLS are described. Before the onset of SMEI, MAE, and ABPE/PLS, the development of the child is usually normal. In contrast, in LGS, development is frequently retarded at the onset, depending on the etiopathogenesis of the underlying brain disease. The course of MAE is highly variable with regard to seizure outcome (complete remission in some cases, persistent epilepsy in others) and cognitive development (normal or delayed). The course of LGS and SMEI is generally poor, both with regard to the epilepsy and to the cognitive development whereas the course and seizure outcome of ABPE/PLS is favorable; the patients will be seizure-free at puberty. However, the neuropsychological outcome is less favorable; most patients remain mentally retarded. OBJECTIVE: To identify neuronal networks underlying generalized spike and wave discharges (GSW) in myoclonic astatic epilepsy (MAE). METHODS: Simultaneous EEG-fMRI recordings were performed in 13 children with MAE. Individual GSW-associated blood oxygenation level-dependent (BOLD) signal changes were analyzed in every patient. A group analysis was performed to determine common syndrome-specific hemodynamic changes across all patients. RESULTS: GSW were recorded in 11 patients, all showing GSW-associated BOLD signal changes. Activation was detected in the thalamus (all patients), premotor cortex (6 patients), and putamen (6 patients). Deactivation was found in the default mode areas (7 patients). The group analysis confirmed activations in the thalamus, premotor cortex, putamen, and cerebellum and deactivations in the default mode network. CONCLUSIONS: In addition to the thalamocortical network, which is commonly found in idiopathic generalized epilepsies, GSW in patients with MAE are characterized by BOLD signal changes in brain structures associated with motor function. The results are in line with animal studies demonstrating that somatosensory cortex, putamen, and cerebellum are involved in the generation of myoclonic seizures. The involvement of these structures might predispose to the typical seizure semiology of myoclonic jerks observed in MAE. Myoclonic astatic epilepsy (MAE) belongs to the epilepsies with generalized seizures. MAE occurs in 1-2% of all childhood epilepsies up to age 9. This disease is characterized by various clinical and EEG criteria. The course of this epileptic syndrome is variable but influenced by an early diagnosis and by a specific treatment. We studied 36 drop seizures in 5 patients with myoclonic astatic epilepsy of early childhood (MAEE) with simultaneous split-screen video recording and polygraph. Sixteen were falling attacks and 20 were either less severe attacks exhibiting only deep head nodding or seizures equivalent to drop attacks in terms of ictal pattern but recorded in the supine position. All seizures except those that occurred in patients in the supine position showed sudden momentary head dropping or collapse of the whole body downward. Recovery to the preictal position was observed in 0.3-1 s. As a result of carefully repeated observations, the 36 seizures were classified as myoclonic flexor type in 9, myoclonic atonic type in 2, and atonic type, with and without transient preceding symptoms in the remaining 25. The MF seizure was characterized by sudden forward flexion of the head and trunk as well as both arms, which caused the patient to fall. In the myoclonic atonic seizure, patients showed brief myoclonic flexor spasms, immediately followed by atonic falling. The AT seizure showed abrupt atonic falling, with and without transient preceding facial expression change and/or twitching of extremities. The ictal EEGs of all 36 seizures exhibited generalized bilaterally synchronous single or multiple spike(s) and wave discharges. Atonic drop attacks appear to be a common cause of ictal epileptic falling in MAEE. Mutations in SCN1A gene, encoding the voltage-gated sodium channel α1-subunit, are found to be associated with severe myoclonic epilepsy in infancy or Dravet syndrome (DS), but only rarely with the myoclonic astatic epilepsy (MAE, or Doose syndrome). We report on two patients with SCN1A mutations and severe epilepsy within the spectrum of generalized epilepsy with febrile seizures plus syndrome (GEFS+), the phenotypes being consistent with DS and MAE, respectively. Analysis of SCN1A revealed a heterozygous de novo frameshift mutation (c.4205_4208delGAAA) in the patient with DS, and a recurrent missense mutation (c.3521C>G) in that suffering from MAE. The missense mutation has been reported in patients with neurological diseases of various manifestations, which suggests that this variability is likely to result from the modifying effects of other genetic or environmental factors. DS phenotype has been mainly found associated with truncation mutations, while predominantly missense mutations and very few prematurely terminating substitutions have been reported in GEFS+ patients. A study of epileptic drop attacks (EDA) by simultaneous video-polygraphic recordings was carried out in one epileptic patient with myoclonic astatic seizures (Doose syndrome). EDA was shown to correspond to a burst of generalized bilaterally synchronous spike and wave complexes (GBSSW) at 3 Hz. Absence seizures were also observed with a burst of GBSSW with similar characteristics. The amplitudes of the corresponding slow wave component of GBSSW among the three intensities of atonia, i.e. complete atonia, minor atonia and no discernible atonia (control), was compared. A high amplitude was demonstrated to correspond with more pronounced atonia and a lower amplitude with reduced or absent atonia. These findings suggest that EDA corresponding to GBSSW have a neurophysiological mechanism in common with absence seizures, and that if the GBSSW is intense, it may be sufficient to cause immediate loss of global muscle tone. OBJECTIVE: To investigate the effect of ketogenic diet (KD) on the clinical and electroencephalogram features in children with pharmacoresistant epileptic encephalopathy. METHOD: Thirty-one children (19 boys, 12 girls) aged 7 months to 7 years (mean 2 years 5 month) with epilepsy refractory to conventional antiepileptic drugs (AEDs) were included in this study. In addition to their original AED treatment, the children were assigned to different ketogenic diets based on their age. The prospective electro-clinical assessment was performed prior to the KD and then one week, one month and again 3 months after the initiation of therapy, respectively. RESULT: The reduction of seizure frequency in 52%, 68% and 71% of all patients exceeded 50% one week, one month and three months after KD treatment respectively. KD is particularly effective in myoclonic astatic epilepsy (MAE; Doose Syndrome) and West syndrome with 100% and 81.25% of the patients having a greater than 50% seizure reduction, respectively. After 3 months of KD treatment, more than 2/3 patients experienced a reduction in interictal epileptiform discharges (IEDs) and improvement in EEG background. CONCLUSION: The clinical and electroencephalographic improvement confirms that KD is beneficial in children with refractory epilepsy. PURPOSE: Before 1986, the spectrum of childhood epilepsies, including Lennox-Gastaut syndrome (LGS) and Doose syndrome (DS), known collectively as "epilepsia myoclonica astatica," was believed to represent a single disease. More recently, some investigators have considered these syndromes to be parts of a continuum. To clarify these theories, neurobiologic factors of the syndromes were studied to determine which qualities were shared and which were unique. METHODS: A retrospective (1975-1985), community-based (Helsinki metropolitan area and the province of Uusimaa) study was designed to seek children with features of LGS and DS. It was assumed that recall bias and the selection of documented history would be similar throughout the group. Ranks of increasing pathology were assigned to different seizure types, EEG results, and drug treatments. A similar procedure was applied to epidemiologic data. Spearman rank-order correlations were calculated to determine which features correlated with LGS and which correlated with less severe epilepsy. RESULTS: The survey comprised 75 patients with broadly defined LGS. The annual incidence was 2 in 100,000 children aged 0 to 14 years. Prenatal or perinatal abnormalities did not correlate with severity of epilepsy. As compared with the relatively favorable ranks, the severe epilepsy ranks were more often associated with an early onset of epilepsy, an infectious disease at the onset, delayed development before epilepsy, abnormalities in neurologic or neuroradiologic examinations, and a deteriorating course of the condition. CONCLUSIONS: Patients with LGS are more likely than patients with less severe epilepsy to have a younger age at onset of epilepsy, an infection or both, and a deteriorating course of the condition. Doose syndrome, otherwise traditionally known as myoclonic-astatic epilepsy, was first described as a unique epilepsy syndrome by Dr Hermann Doose in 1970. In 1989, the International League Against Epilepsy classified it formally as a symptomatic generalized epilepsy, and 20 years later it was renamed 'epilepsy with myoclonic-atonic seizures'. In this review, we discuss the components of this unique disorder including its incidence, clinical features, and electroencephalographic findings. Recent evidence has suggested possible genetic links to the GEFS+ (generalized epilepsy with febrile seizures plus) family, and, additionally, some children with structural brain lesions can mimic the Doose syndrome phenotype. Treatment strategies such as corticosteroids, ethosuximide, and valproate have been described as only partially effective, but newer anticonvulsants, such as levetiracetam and zonisamide, may provide additional seizure control. The most effective treatment reported to date appears to be the ketogenic diet. Prognosis is quite varied in this disorder; however, many children can have a remarkably normal neurodevelopmental outcome. PURPOSE OF REVIEW: Despite myriad anticonvulsants available and in various stages of development, there are thousands of children and adults with epilepsy worldwide still refractory to treatment and not candidates for epilepsy surgery. Many of these patients will now turn to dietary therapies such as the ketogenic diet, medium-chain triglyceride diet, modified Atkins diet, and low glycemic index treatment. RECENT FINDINGS: In the past several years, neurologists are finding new indications to use these dietary treatments, perhaps even as first-line therapy, including infantile spasms, myoclonic-astatic epilepsy (Doose syndrome), Dravet syndrome, and status epilepticus (including FIRES syndrome). Adults are also one of the most rapidly growing populations being treated nowadays; this group of patients previously was not typically offered these treatments. In 2009, two controlled trials of the ketogenic diet were published, as well as an International Expert Consensus Statement on dietary treatment of epilepsy. Ketogenic diets are also now being increasingly studied for neurological conditions other than epilepsy, including Alzheimer's disease and cancer. Insights from basic science research have helped elucidate the mechanisms by which metabolism-based therapy may be helpful, in terms of both an anticonvulsant and possibly a neuroprotective effect. SUMMARY: Dietary therapy for epilepsy continues to grow in popularity worldwide, with expanding use for adults and conditions other than epilepsy. The ketogenic diet (KD) has been used successfully in a variety of epilepsy syndromes. This includes syndromes with multiple etiologies, including Lennox-Gastaut syndrome and infantile spasms; developmental syndromes of unknown etiology, such as Landau-Kleffner syndrome; and idiopathic epilepsies, such as myoclonic-astatic (Doose) epilepsy. It also includes syndromes where genetics play a major role, such as Dravet syndrome, tuberous sclerosis, and Rett syndrome. Study of the KD in humans and animals harboring various genetic mutations may yield insights into the diet's mechanisms. Comparison of the diet's effectiveness with other treatments in specific syndromes may be another useful tool for mechanistic studies. The diet's utility in epilepsy syndromes of various etiologies and in some neurodegenerative disorders suggests it may have multiple mechanisms of action. The antiepileptic drug felbamate has demonstrated efficacy against a variety of seizure types in the pediatric population, particularly seizures associated with Lennox-Gastaut syndrome. Postmarketing experience, however, revealed serious idiosyncratic adverse effects not observed during clinical trials, including aplastic anemia and liver failure. As a result, many physicians have been hesitant to prescribe felbamate. This retrospective study evaluated the efficacy of felbamate in a pediatric population with intractable epilepsy. Of 38 patients, 22 had Lennox-Gastaut syndrome (58%); 6 had myoclonic-astatic epilepsy of Doose (16%); 5 had symptomatic generalized epilepsy, not otherwise specified (13%); and 5 had symptomatic localization-related epilepsy (13%). Most patients had multiple seizure types and had been tried on a variety of antiepileptic medications. With felbamate treatment, 6 patients (16%) became seizure free, including 4 of the 6 patients with myoclonic-astatic epilepsy of Doose; 24 patients (63%) had a greater than 50% reduction in seizure frequency. In this population felbamate appeared to be safe, with minimal adverse effects. The study is limited by the small number of patients and by its retrospective nature, but nonetheless adds to the evidence that felbamate is an important antiepileptic drug for medically refractory epilepsy in children and is well tolerated with few adverse effects. |
352 | Have mutations in the GARS gene been identified to cause Charcot-Marie-Tooth Disease Type 2D (CMT2D)? | Charcot-Marie-Tooth disease type 2D (CMT2D) is caused by missense mutations in the glycyl-tRNA synthetase gene (GARS). | [23990368, 17035524, 16769947, 20301420, 19412816, 16982418, 22462675, 22144914, 20301462, 17663003, 16014653] | 459 | Charcot-Marie-Tooth disease type 2D is a hereditary axonal and glycyl-tRNA synthetase (GARS)-associated neuropathy that is caused by a mutation in GARS. Here, we report a novel GARS-associated mouse neuropathy model using an adenoviral vector system that contains a neuronal-specific promoter. In this model, we found that wild-type GARS is distributed to peripheral axons, dorsal root ganglion (DRG) cell bodies, central axon terminals, and motor neuron cell bodies. In contrast, GARS containing a G240R mutation was localized in DRG and motor neuron cell bodies, but not axonal regions, in vivo. Thus, our data suggest that the disease-causing G240R mutation may result in a distribution defect of GARS in peripheral nerves in vivo. Furthermore, a distributional defect may be associated with axonal degradation in GARS-associated neuropathies. Sporadic juvenile muscular atrophy of the distal upper extremity or Hirayama's disease (HD) and autosomal dominant motor distal neuronopathy/axonopathy (CMT2D/dSMA-V), produced by glycyl-tRNA synthetase (GARS) gene mutations, share some clinical features including: young age of onset, predilection for the distal upper extremity, asymmetry, sparing of proximal muscles and unusual cold sensitivity. However, incomplete penetrance of GARS gene mutations may account for apparently non-familial cases. In order to inquire whether GARS gene mutations are associated with HD we studied seven patients fulfilling the clinical and electrodiagnostic criteria for HD. All patients underwent MRI of cervical spine that excluded compressive myelopathy in neutral position and intramedullary pathology. Each patient was tested for the presence of mutations in GARS by sequencing all coding exons amplified from genomic DNA. No pathogenic mutations were found, excluding the role of GARS gene as a possible factor in the aetiology of HD in this cohort. Of the many inherited Charcot-Marie-Tooth peripheral neuropathies, type 2D (CMT2D) is caused by dominant point mutations in the gene GARS, encoding glycyl tRNA synthetase (GlyRS). Here we report a dominant mutation in Gars that causes neuropathy in the mouse. Importantly, both sensory and motor axons are affected, and the dominant phenotype is not caused by a loss of the GlyRS aminoacylation function. Mutant mice have abnormal neuromuscular junction morphology and impaired transmission, reduced nerve conduction velocities, and a loss of large-diameter peripheral axons, without defects in myelination. The mutant GlyRS enzyme retains aminoacylation activity, and a loss-of-function allele, generated by a gene-trap insertion, shows no dominant phenotype in mice. These results indicate that the CMT2D phenotype is caused not by reduction of the canonical GlyRS activity and insufficiencies in protein synthesis, but instead by novel pathogenic roles for the mutant GlyRS that specifically affect peripheral neurons. Mutations in the GARS gene cause Charcot-Marie-Tooth 2D and distal spinal muscular atrophy type V - allelic disorders characterized by predominantly distal upper extremity weakness and atrophy, typically beginning during the second decade of life. We report monozygotic twin girls with onset of weakness in infancy and a previously reported GARS mutation within the anticodon-binding domain. The severity and remarkable similarity in phenotypes of these girls and the reported case suggest that mutations within the anticodon-binding domain are more damaging to aminoacyl tRNA synthetase function than those within other domains of GARS. We describe clinical, electrophysiological, histopathological and molecular features of a unique disease caused by mutations in the glycyl-tRNA synthetase (GARS) gene. Sixty patients from five multigenerational families have been evaluated. The disease is characterized by adolescent onset of weakness, and atrophy of thenar and first dorsal interosseus muscles progressing to involve foot and peroneal muscles in most but not all cases. Mild to moderate sensory deficits develop in a minority of patients. Neurophysiologically confirmed chronic denervation in distal muscles with reduced compound motor action potentials were features consistent with both motor neuronal and axonal pathology. Sural nerve biopsy showed mild to moderate selective loss of small- and medium-sized myelinated and small unmyelinated axons, although sensory nerve action potentials were not significantly decreased. Based on the presence or absence of sensory changes, the disease phenotype was initially defined as distal spinal muscular atrophy type V (dSMA-V) in three families, Charcot-Marie-Tooth disease type 2D (CMT2D) in a single family, and as either dSMA-V or CMT2D in patients of another large family. Linkage to chromosome 7p15 and the presence of disease-associated heterozygous GARS mutations have been identified in patients from each of the five studied families. We conclude that patients with GARS mutations present a clinical continuum of predominantly motor distal neuronopathy/axonopathy with mild to moderate sensory involvement that varies between the families and between members of the same family. Awareness of these overlapping clinical phenotypes associated with mutations in GARS will facilitate identification of this disorder in additional families and direct future research toward better understanding of its pathogenesis. |
353 | Which treatment leads to an increase in neutrophil counts in severe congenital neutropenia? | In phase I/II/III studies in patients with severe congenital and cyclic neutropenia, treatment with recombinant human granulocyte colony-stimulating factor (r-metHuG-CSF) resulted in a rise in the absolute neutrophil counts (ANC) and a reduction in infections | [7529539, 1705835, 2683920, 10779444, 21052952, 1689595, 16822461] | 460 | Congenital neutropenias include a heterogenous group of diseases characterized by a decrease in circulating neutrophils. In phase I/II/III studies in patients with severe congenital and cyclic neutropenia, treatment with recombinant human granulocyte colony-stimulating factor (r-metHuG-CSF) resulted in a rise in the absolute neutrophil counts (ANC) and a reduction in infections. We report the effects of long-term safety of subcutaneous r-metHuG-CSF administration in 54 patients (congenital n = 44. cyclic n = 10) treated for 4-6 years. A sustained ANC response was seen in 40/44 severe congenital neutropenia patients and 10/10 cyclic neutropenia patients. Two patients required an increase of > 25% in dose to maintain a clinical response; one patient became refractory to therapy. A significant decrease in the incidence of severe infections and the need for intravenous antibiotics was noted. Significant adverse events noted which may or may not be related to therapy included: osteopenia (n = 15), splenomegaly (n = 12), hypersplenism (n = 1), vasculitis (n = 2), glomerulonephritis (n = 1), BM fibrosis (n = 2), MDS/leukaemia (n = 3), and transient inverted chromosome 5q with excess blasts (n = 1). R-metHuG-CSF has been well tolerated in the majority of patients and resulted in a long-term improvement in their clinical status. Severe congenital neutropenia (SCN) is a disorder of myelopoiesis characterized by severe neutropenia or absence of blood neutrophils secondary to a maturational arrest at the level of promyelocytes. We examined peripheral blood mononuclear cells (PBMC) of SCN patients who demonstrated normalization of their blood neutrophil counts in a phase II clinical study with recombinant human granulocyte colony-stimulating factor (rhG-CSF). When stimulated in vitro with bacterial lipopolysaccharides (LPS), PBMC of those SCN patients produced G-CSF activity, as judged by proliferation induction of the murine leukemia cell line, NFS-60. Western and Northern blot analysis showed G-CSF protein and G-CSF-mRNA indistinguishable in size from those of normal controls. We conclude that PBMC of the SCN patients tested are capable of synthesizing and secreting biologically active G-CSF in vitro. STUDY OBJECTIVE: To define the clinical and hematologic effects of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) on patients with chronic severe neutropenia. DESIGN: Open-label, phase II study of rhGM-CSF. SETTING: Inpatient hematology and surgery clinic at a university medical center. PATIENTS: Four consecutive patients with chronic severe neutropenia, which in two cases was complicated by severe infection, in one case by perianal fistula, and in one case by complete rectal prolapse. Two patients had chronic idiopathic neutropenia; one patient had congenital neutropenia (myelokathexis); and one patient had autoimmune neutropenia. INTERVENTIONS: The rhGM-CSF was given intravenously or subcutaneously at starting dosages of 150 to 1000 micrograms/m2 body surface area.d for 12 to 14 consecutive days. Two patients received a second course of daily rhGM-CSF treatment after a nontreatment interval of 14 to 20 days. MEASUREMENTS AND MAIN RESULTS: In all four patients, the absolute neutrophil counts increased from less than 0.25 x 10(9)/L to 3.2 to 19.2 x 10(9)/L within 2 weeks of beginning rhGM-CSF therapy. Two patients had life-threatening infections that resolved during therapy. The two other patients had major ano-rectal surgery during rhGM-CSF treatment and had no postoperative infections. CONCLUSIONS: In patients with chronic neutropenia, rhGM-CSF may increase neutrophil counts. This therapy may be a useful adjunct to antibiotic therapy for patients with infection and perioperatively for patients having anorectal surgery. Severe congenital neutropenia (SCN) or Kostmann syndrome is a disorder of myelopoiesis characterized by a maturation arrest at the stage of promyelocytes or myelocytes in bone marrow and absolute neutrophil counts less than 200/microL in peripheral blood. Treatment of these patients with granulocyte colony-stimulating factor (G-CSF) leads to a significant increase in circulating neutrophils and a reduction in infection-related events in more than 95% of the patients. To date, little is known regarding the underlying pathomechanism of SCN. G-CSF-induced neutrophils of patients with SCN are functionally defective (eg, chemotaxis, superoxide anion generation, Ca(++ )mobilization). Two guanosine triphosphatases (GTPases), Rac2 and RhoA, were described to be involved in many neutrophil functions. The expression of these GTPases and their regulation in patients' neutrophils were of interest. This study determined that the guanosine diphosphate (GDP)-dissociation inhibitor RhoGDI is overexpressed at the protein level in patients' neutrophils and that overexpression is a result of G-CSF treatment. RhoA and LyGDI are expressed at similar levels, whereas Rac2 shows a decreased expression. In addition, association of Rac2 and RhoGDI or LyGDI is abrogated or not detectable based on the low Rac2 expression in patients' neutrophils. (Blood. 2000;95:2947-2953) Patients with severe chronic neutropenia have blood neutrophil level <0.5 × 10(9)/L, predisposing them to increased susceptibility to life-threatening bacterial infections. This chapter focuses on cyclic and congenital neutropenia, two very interesting and rare hematological conditions causing severe chronic neutropenia. Both disorders respond well to treatment with the myeloid growth factor, granulocyte colony-stimulating factor (G-CSF). This chapter describes the basic features of these diseases and addresses several current clinical issues regarding their diagnosis and management. Cyclic neutropenia is a rare, inherited autosomal dominant disorder due to mutations in the gene for neutrophil elastase (ELA-2 or ELANE). Usually these patients have regular oscillation of blood neutrophil counts with periods of severe neutropenia occurring every 21 days. During these periods, they have painful mouth ulcers, fevers, and bacterial infections. The most severe consequences are gangrene, bacteremia, and septic shock. Cyclic neutropenia patients respond well to treatment with granulocyte colony-stimulating factor (G-CSF) given by subcutaneous injections on a daily or alternate-day basis. Severe congenital neutropenia is also a rare hematological disease, but it is probably more common than cyclic neutropenia. Blood neutrophils are extremely low on a continuing basis; the levels may be <0.2 × 10(9)/L, and the risk of severe bacterial infections is even greater than in cyclic neutropenia. The majority of cases are due to autosomal dominant inheritance of mutations in the ELA-2 or ELANE gene. Less commonly, mutations in HAX-1, G6PC3, and other genes cause this disorder. Treatment with G-CSF is usually effective, but the dose of G-CSF required to normalize blood neutrophils varies greatly. Ten to thirty percent of severe congenital neutropenia patients evolve to develop acute myeloid leukemia, necessitating careful clinical monitoring. Severe congenital neutropenia (CN) includes a variety of hematologic disorders characterized by severe neutropenia, with absolute neutrophil counts (ANC) below 0.5 x 10(9)/L, and associated with severe systemic bacterial infections from early infancy. One subtype of CN, Kostmann syndrome, is an autosomal recessive disorder, characterized histopathologically by early-stage maturation arrest of myeloid differentiation. CN with similar clinical features occurs as an autosomal dominant disorder and many sporadic cases also have been reported. This genetic heterogeneity suggests that several pathophysiological mechanisms may lead to this common clinical phenotype. Recent studies on the genetic bases of CN have detected inherited or spontaneous point mutations in the neutrophil elastase gene (ELA 2) in about 60% to 80% of patients and, less commonly, mutations in other genes. Acquisition of additional genetic defects during the course of the disease, for example, granulocyte colony-stimulating factor (G-CSF) receptor gene mutations and cytogenetic aberrations, indicates an underlying genetic instability as a common feature for all congenital neutropenia subtypes. Data on more than 600 patients with CN collected by the Severe Chronic Neutropenia International Registry (SCNIR) demonstrate that, regardless of the particular CN subtype, more than 95% of these patients respond to recombinant human (rHu)G-CSF with ANCs that can be maintained above 1.0 x 10(9)/L. Adverse events include mild splenomegaly, osteoporosis, and malignant transformation into myelodysplasia (MDS)/leukemia. If and how G-CSF treatment impacts on these adverse events is not fully understood. In recent analyses the influence of the G-CSF dose required to achieve neutrophil response (ANC >1,000/microL) in the risk of developing acute myeloid leukemia (AML) has been reported. Hematopoietic stem cell transplantation (HSCT) is still the only treatment available for patients who are refractory to G-CSF treatment. |
354 | Which genes are affected in ROMANO-WARD syndrome? | The genes involved in ROMANO-WARD syndrome are KCNQ1, KCNE1, KCNE2, KCNH2, SCN5A, CAV3, SCN4B, AKAP9, SNTA1, KCNJ5 and Ankyrin-B. | [20850564, 10868746, 18752142, 16931984, 10482963, 10973849, 12442276, 20981542, 16981927, 17560885, 10613047, 14756674, 12388934, 15511625, 10953551, 11216980, 23000022, 9848024, 16831322, 9641694, 19490272, 10898405, 9511785, 15306731, 19540844, 10220144, 10560244, 9791861, 15950200, 22461049, 20301308] | 461 | BACKGROUND: Loss-of-function mutations in the gene KCNQ1 encoding the Kv7.1 K(+) channel cause long QT syndrome type 1 (LQT1), whereas gain-of-function mutations are associated with short QT syndrome as well as familial atrial fibrillation (FAF). However, KCNQ1 mutation pleiotropy, which is capable of expressing both LQT1 and FAF, has not been demonstrated for a discrete KCNQ1 mutation. The genotype-phenotype relationship for a family with FAF suggests a possible association with the LQT1 p.Arg231Cys-KCNQ1 (R231C-Q1) mutation. OBJECTIVE: The purpose of this study was to determine whether R231C-Q1 also can be linked to FAF. METHODS: The R231C-Q1 proband with AF underwent genetic testing for possible mutations in 10 other AF-linked genes plus KCNH2 and SCN5A. Sixteen members from five other R231C-positive LQT1 families were genetically tested for 21 single nucleotide polymorphisms (SNPs) to determine if the FAF family had discriminatory SNPs associated with AF. R231C-Q1 was expressed with KCNE1 (E1) in HEK293 cells, and Q1E1 currents (I(Q1E1)) were analyzed using the whole-cell patch-clamp technique. RESULTS: Genetic analyses revealed no additional mutations or discriminatory SNPs. Cells expressing WT-Q1 and R231C-Q1 exhibited some constitutively active I(Q1E1) and smaller maximal I(Q1E1) compared to cells expressing WT-Q1. CONCLUSION: Constitutively active I(Q1E1) and a smaller peak I(Q1E1) are common features of FAF-associated and LQT1-associated mutations, respectively. These data suggest that the mixed functional properties of R231C-Q1 may predispose some families to LQT1 or FAF. We conclude that R231C is a pleiotropic missense mutation capable of LQT1 expression, AF expression, or both. Mutations in the KCNQ1, HERG, SCN5A, minK and MiRP1 genes cause long QT syndrome (LQTS), of which there are two forms: the Romano Ward syndrome and the Jervell and Lange-Nielsen syndrome. We have performed DNA sequencing of the LQTS-associated genes in 169 unrelated patients referred for genetic testing with respect to Romano Ward syndrome and in 13 unrelated patients referred for genetic testing with respect to Jervell and Lange-Nielsen syndrome. A total of 37 different mutations in the 5 genes, of which 20 were novel, were identified. Among patients with the most stringent clinical criteria of Romano Ward syndrome, a mutation was identified in 71%. Twelve of the 13 unrelated patients referred for genetic testing with respect to Jervell and Lange-Nielsen syndrome were provided with a molecular genetic diagnosis. Cascade genetic screening of 505 relatives of index patients with molecularly defined LQTS identified 251 mutation carriers. The observed penetrance was 41%. Although caution must be exerted, the prevalence of heterozygotes for mutations in the LQTS-associated genes in Norway could be in the range 1/100-1/300, based on the prevalence of patients with Jervell and Lange-Nielsen syndrome. BACKGROUND: Anesthesia in patients with long QT syndrome (LQTS) is a matter of concern. Congenital LQTS is most frequently caused by mutations in KCNQ1 (Kv7.1), whereas drug-induced LQTS is a consequence of HERG (human ether-a-go-go-related gene) channel inhibition. The aim of this study was to investigate whether the LQT1 mutation A344V in the S6 region of KCNQ1, at a position corresponding to the local anesthetic binding site in HERG, may render drug insensitive KCNQ1 channels into a toxicologically relevant target of these pharmacologic agents. This may suggest that LQTS constitutes not only a nonspecific but also a specific pharmacogenetic risk factor for anesthesia. METHODS: The authors examined electrophysiologic and pharmacologic properties of wild-type and mutant KCNQ1 channels. The effects of bupivacaine, ropivacaine, and mepivacaine were investigated using two-electrode voltage clamp and whole cell patch clamp recordings. RESULTS: The mutation A344V induced voltage-dependent inactivation in homomeric KCNQ1 channels and shifted the voltage dependence of KCNQ1/KCNE1 channel activation by +30 mV. The mutation furthermore increased the sensitivity of KCNQ1/KCNE1 channels for bupivacaine 22-fold (KCNQ1wt/KCNE1: IC50 = 2,431 +/- 582 microM, n = 20; KCNQ1A344V/KCNE1: IC50 = 110 +/- 9 microM, n = 24). Pharmacologic effects of the mutant channels were dominant when mutant and wild-type channels were coexpressed. Simulation of cardiac action potentials with the Luo-Rudy model yielded a prolongation of the cardiac action potential duration and induction of early afterdepolarizations by the mutation A344V that were aggravated by local anesthetic intoxication. CONCLUSIONS: The results indicate that certain forms of the LQTS may constitute a specific pharmacogenetic risk factor for regional anesthesia. This report describes a three-generation family with a severe phenotype of long-QT syndrome-1 (LQTS-1) caused by a single nucleotide mutation in the KQT-like, voltage-gated potassium channel-1 gene (KCNQ1; MIM 607542). Two members of the family died suddenly in their childhood, and all eight surviving members with prolonged QT have a heterozygous missense mutation resulting in a glycine-to-glutamate amino acid substitution at position 316 of the potassium channel. In this family, the newly reported mutation, guanine-to-adenosine at position 947 in the KCNQ1 gene, exhibits a dominant trait of LQTS with complete penetrance, in contrast to the relatively reduced clinical penetrance found in most LQTS cases. In a 7-year-old boy with normal hearing suffering from repeated syncope an extremely prolonged QTc interval (up to 700 ms) was found. The mother was completely asymptomatic and the father had an intermittently borderline QTc interval (maximum 470 ms) but no symptoms. In the proband a mutation analysis of KCNQ1 gene revealed a homozygous 1893insC mutation. The parents were heterozygous for this mutation. There was no consanguineous marriage in the family. The clinical relevance of these findings is that apparently normal individuals may have a latent reduction of repolarizing currents, a "reduced repolarization reserve," because they are carriers of latent ion channel genes mutations. The congenital long QT syndrome (LQTS) is characterized by a prolonged QT interval on the surface electrocardiogram and an increased risk of recurrent syncope and sudden cardiac death. Mutations in seven genes have been identified as the molecular basis of LQTS. beta-blockers are the treatment of choice to reduce cardiac symptoms. However, long-term follow-up of genotyped families with LQTS has been rarely reported. We have clinically followed a four-generation family with LQTS being treated with beta-blocker therapy over a period of 23 years. Seven family members were carriers of two amino acid alterations in cis (V254M-V417M) in the cardiac potassium channel gene KCNQ1. Voltage-clamp recordings of mutant KCNQ1 protein in Xenopus oocytes showed that only the V254M mutation reduced the IKs current and that the effect of the V417M variant was negligible. The family exhibited the complete clinical spectrum of the disease, from asymptomatic patients to victims of sudden death before beta-blocker therapy. There was no significant reduction in QTc (556 +/- 40 ms(1/2) before therapy, 494 +/- 20 ms(1/2) during 17 years of treatment; n = 5 individuals). Of nine family members, one female died suddenly before treatment, three females of the second generation were asymptomatic, and four individuals of the third and fourth generation were symptomatic. All mutation carriers were treated with beta-blockers and remained asymptomatic for a follow-up up to 23 years. Long-term follow-up of a LQT1 family with a common mutation (V254M) being on beta-blocker therapy was effective and safe. This study underscores the importance of long-term follow-up in families with specific LQT mutations to provide valuable information for clinicians for an appropriate antiarrhythmic treatment. KCNQ1 (formerly called KVLQT1) is a Shaker-like voltage-gated potassium channel gene responsible for the LQT1 sub-type of LQTS. In general, heterozygous mutations in KCNQ1 cause Romano-Ward syndrome (LQT1 only), while homozygous mutations cause JLNS (LQT1 and deafness). To date, more than 100 families with mutations in this gene have been reported, most with their own novel 'private' mutations. The majority of these mutations are missense. However, other types of mutations, such as deletions, frame-shifts and splice-donor errors have also been reported. There is one frequently reported mutated region (the 'hot-spot'). KCNQ1 is now believed to be the most commonly mutated gene in LQTS. The combination of normal and mutant KCNQ1 alpha-subunits has been found to form abnormal IKS channels, hence mutations associated with the KCNQ1 gene are also believed to act mainly through a dominant-negative mechanism (the mutant form interferes with the function of the normal wild-type form through a 'poison pill' type mechanism) or loss of function mechanism. Even in the case of carriers of the same mutation, it is currently unknown why there are significant clinical phenotype variations in LQT1 patients. This question could be answered by increasing the number of patient genotypes studied. LQT1 patients experience a majority of their cardiac events (62%) during exercise, and only 3% occur during rest or sleep. Of the patients who experienced cardiac events while swimming, 99% were LQT1. Auditory stimuli are rare and occur in only 2% of patients. However, both lethal and non-lethal events follow the same pattern. Romano-Ward syndrome (RWS), the autosomal dominant form of the congenital long QT syndrome, is characterised by prolongation of the cardiac repolarisation process associated with ventricular tachyarrhythmias of the torsades de pointes type. Genetic studies have identified mutations in six ion channel genes, KCNQ1, KCNH2, SCN5A, KCNE1 and KCNE2 and the accessory protein Ankyrin-B gene, to be responsible for this disorder. Single-strand conformation polymorphism (SSCP) analysis and subsequent DNA sequence analysis have identified a KCNQ1 mutation in a family that were clinically conspicuous due to several syncopes and prolonged QTc intervals in the ECG. The mutant subunit was expressed and functionally characterised in the Xenopus oocyte expression system. A novel heterozygous missense mutation with a C to T transition at the first position of codon 343 (CCA) of the KCNQ1 gene was identified in three concerned family members (QTc intervals: 500, 510 and 530 ms, respectively). As a result, proline 343 localised within the highly conserved transmembrane segment S6 of the KCNQ1 channel is replaced by a serine. Co-expression of mutant (KCNQ1-P343S) and wild-type (KCNQ1) cRNA in Xenopus oocytes produced potassium currents reduced by approximately 92%, while IKs reconstitution experiments with a combination of KCNQ1 mutant, wild-type and KCNE1 subunits yielded currents reduced by approximately 60%. A novel mutation (P343S) identified in the KCNQ1 subunit gene of three members of a RWS family showed a dominant-negative effect on native IKs currents leading to prolongation of the heart repolarisation and possibly increases the risk of malign arrhythmias with sudden cardiac death. INTRODUCTION: Progress in molecular genetics contributed to the discovery of pathophysiologic mechanisms of hereditary diseases as well as better diagnostics and efficient therapy. Several defective ge- nes have been discovered on different chromosomes (3,4,7,11 and 21 pair of chromosomes), and also their relationship with some types of LQTS (long QT syndrome). Gene dysfunction leads to the dysfunction of ion channels, which consequently causes prolonged duration of repolarization in cardiac muscle. These changes are manifested on electrocardiogram with prolonged duration of QT interval (over 0.44 sec.). Familial forms of LQTS are inherited as autosomal dominant (Roman Ward syndrome) and autosomal recessive (Jervell Lange-Neilsen syndrome). The final form of LQTS is defined even with hearing loss. Clinical survey: malignant ventricular arrhythmia, syncope and sudden death. MOLECULAR ARCHITECTURE OF VOLTAGE-GATED ION CHANNELS: Duration of voltage-gated ion can be regulated by Na and K channels. Cardiac action potential plateau is an indicator of the balance of inward and outward ionic currents. During this process of voltage-gated potential two currents are activated: depolarized inward current (it happens in the Na channels) and repolarized outward current (it happens in the K channels). Na channels are polypeptides incorporated in cell membrane. Their main function is to control excitability in myocardial cell. They consist of two subunits: alpha and beta. Class Ib of anty-arrhythmics (Lidocaine, Mexiletine and Tocainide) as well as Diphenylhydantoin blocks Na channels in the state of inactivation, in fact, during the depolarization of the cell. For controlling the cardiac voltage-gated potential the most important are voltage-sensitive K channels. For appearance of K ions delayed refraction of K channels (Kv) is of importance. Depending on the velocity of activation, Kv are divided into two groups: channels with rapid activation (Kvr) and channels with slow activation (Kvs). By activation of these delayed rectification channels (Kv) beta agonists shorten the action potential of the heart. GENETIC ASPECTS OF LQTS: Five loci which are connected with Romano Ward's familial form of LQTS have been described up to now. Specific mutant gene is responsible for function of K channels and it is located on short branch (part) of the 11-th pair of chromosome 11p15.5 (KVLQT-LQT1), long branch of the 7-th pair of chromosomes 7q35-36 (K- HERG-LQT2), as well as on the 21-st pair of chromosome (KCNE1-LQT5). Defective gene which is responsible for the function of Na channels is located on the short branch of chromosome 3p21-24 (SCN5A-LQT3). The gene which is located on the long branch of the 4-th pair of chromosome 4q25-27 (LQT4) has not been examined sufficiently. Persons with Jevell Lange-Neilsen syndrome inherit pathological allele from both parents (KvLQT1 or LQT5-minK). CONNECTION BETWEEN ION CHANNELS AND GENE MUTATION: Among all genes which are responsible for LQTS the most examined one is the so-called HERG gene located on the 7-th pair of chromosome (LQT2). Mutation of this gene leads to reduction in strength of outward K currents or to the dysfunction of K channel proteins. Mutant gene causes so-called missense mutation, in fact wrong change of amino acid in the protein chain. Among all described LQTS the most frequent and the most malignant form is LQT1. In 99% cases psychophysical stress can cause arrhythmia, syncope or sudden death. LQT3 and LQT5 are very rare. CONCLUSION: Genetic screening in LQTS patients provides discovery of risk population which demands anti-arrhythmic therapy with beta-blockers. A lot of arguments speak in favour of genetic screening in cases with LQTS. It is considered that if the diagnosis is known, genetic testing is not necessary, but it is useful. Moreover, it is obligatory in symptomatic cases as well as in those with suspected diagnosis of LQTS. OBJECTIVES: We took advantage of the genetic isolate of Finns to characterize a common long QT syndrome (LQTS) mutation, and to estimate the prevalence of LQTS. BACKGROUND: The LQTS is caused by mutations in different ion channel genes, which vary in their molecular nature from family to family. METHODS: The potassium channel gene KCNQ1 was sequenced in two unrelated Finnish patients with Jervell and Lange-Nielsen syndrome (JLNS), followed by genotyping of 114 LQTS probands and their available family members. The functional properties of the mutation were studied using a whole-cell patch-damp technique. RESULTS: We identified a novel missense mutation (G589D or KCNQ1-Fin) in the C-terminus of the KCNQ1 subunit. The voltage threshold of activation for the KCNQ1-Fin channel was markedly increased compared to the wild-type channel. This mutation was present in homozygous form in two siblings with JLNS, and in heterozygous form in 34 of 114 probands with Romano-Ward syndrome (RWS) and 282 family members. The mean (+/- SD) rate-corrected QT intervals of the heterozygous subjects (n = 316) and noncarriers (n = 423) were 460 +/- 40 ms and 410 +/- 20 ms (p < 0.001), respectively. CONCLUSIONS: A single missense mutation of the KCNQ1 gene accounts for 30% of Finnish cases with LQTS, and it may be associated with both the RWS and JLNS phenotypes of the syndrome. The relative enrichment of this mutation most likely represents a founder gene effect. These circumstances provide an excellent opportunity to examine how genetic and nongenetic factors modify the LQTS phenotype. Long QT syndrome (LQTS) 1 is the most common type of inherited LQTS and is linked to mutations in the KCNQ1 gene. We identified a KCNQ1 missense mutation, KCNQ1 G325R, in an asymptomatic patient presenting with significant QT prolongation (QTc, 448-600ms). Prior clinical reports revealed phenotypic variability ranging from the absence of symptoms to syncope among KCNQ1 G325R mutation carriers. The present study was designed to determine the G325R ion channel phenotype and its association with the clinical LQTS presentation. Electrophysiological testing was performed using the Xenopus oocyte expression system. KCNQ1 G325R channels were non-functional and suppressed wild type (WT) currents by 71.1%. In the presence of the native cardiac regulatory ß-subunit, KCNE1, currents conducted by G325R and WT KCNQ1 were reduced by 52.9%. Co-expression of G325R and WT KCNQ1 with KCNE1 shifted the voltage-dependence of I(Ks) activation by 12.0mV, indicating co-assembly of mutant and WT subunits. The dysfunctional biophysical phenotype validates the pathogenicity of the KCNQ1 G325R mutation and corresponds well with the severe clinical presentation revealed in some reports. However, the index patient and other mutation carriers were asymptomatic, highlighting potential limitations of risk assessment schemes based on ion channel data. Recent discoveries of genes involved in long-QT syndrome (LQTS) have led to extensive progress in understanding the molecular basis for this disorder of syncope and sudden cardiac death secondary to ventricular arrhythmias. The emerging unifying theme is that all genes identified to date encode either structural or regulatory subunits for ion channels involved in cardiac repolarization. Defects have been identified in the KCNQ1, HERG, and KCNE1 genes, whose proteins form the K+ channels for the slowly and rapidly inwardly rectifying K+ currents IKs and IKr. Depending on their location and copy number, mutations of KCNQ1 and KCNE1 can cause either autosomal dominant Romano-Ward syndrome or autosomal recessive Jervell and Lange-Nielsen syndrome. The cardiac sodium channel gene, SCN5A, is also mutated in some Romano-Ward cases to produce defects in INa, the cardiac inward Na+ current. The fact that multiple genes are involved and that most LQTS mutations are "private" or "family-specific" complicates molecular diagnosis of LQTS which, currently, is limited to a small number of research laboratories. In future, genotypic determination of LQTS patients and their family members will hopefully lead to improved gene-specific prognostic determinations and therapeutic interventions. OBJECTIVE: Hereditary long QT syndrome (LQTS) is a cardiac disorder characterized by prolongation of QT interval on electrocardiograms (ECGs) and syncope and sudden death caused by a specific multi-polymorphic ventricular tachyarrhythmia known as torsade de pointes. LQTS is caused by mutations in cardiac sodium channel gene SCN5A; potassium channel subunit genes KCNQ1, KCNH2, KCNE1, KCNE2, KCNJ2; calcium channel gene Cav2.1. and ankyrin-B gene ANK2. METHODS: We characterized 77 Chinese LQTS patients with clinical manifestations and mutations in the main LQTS genes, KCNQ1 and KCNH2 using PCR and sequence analysis. RESULTS: The spectrum of ST-T-wave patterns of 24 (31.2%) probands were considered as LQT1, 42 (54.5%) as LQT2 and 3 (3.9%) as LQT3. The remaining 8 (10.3%) could not be characterized. The average age for this population of LQTS patients was (27.6 +/- 16.4) years and the average QTc (561 +/- 70) ms, and the age of the first syncopal attack was (17.6 +/- 14.7) years. The triggering factors for cardiac events happening in these mutation carriers included physical exercise, emotional excitement and auditory irritation. We identified 4 KCNQ1 mutations and 7 KCNH2 mutations. Six of them were first identified with some data already shown. In this paper we showed the data of 6 other mutations. CONCLUSIONS: LQT2 is the most common type of LQTS in Chinese; 2 mutations of KCNQ1 and KCNH2 were first identified in this report; there are some differences between Chinese and North American or European LQTS patients in clinical characters and ECG. BACKGROUND: The congenital long-QT syndrome (LQTS) is a genetically heterogeneous disease characterized by prolonged ventricular repolarization and life-threatening arrhythmias. Mutations of the KVLQT1 gene, a cardiac potassium channel, generate two allelic diseases: the Romano-Ward syndrome, inherited as a dominant trait, and the Jervell and Lange-Nielsen syndrome, inherited as an autosomal recessive trait. METHODS AND RESULTS: A consanguineous family with the clinical phenotype of LQTS was screened for mutations in the KVLQT1 gene. Complementary RNAs for injection into Xenopus oocytes were prepared, and currents were recorded with the double microelectrode technique. A homozygous missense mutation, leading to an alanine-to-threonine substitution at the beginning of the pore domain of the KVLQT1 channel, was found in the proband, a 9-year-old boy with normal hearing, a prolonged QT interval, and syncopal episodes during physical exercise. The parents of the proband were heterozygous for the mutation and had a normal QT interval. The functional evaluation of the mutant channel activity showed reduction in total current, a hyperpolarizing shift in activation, and a faster activation rate consistent with a mild mutation likely to require homozygosity to manifest the phenotype. CONCLUSIONS: These findings provide the first evidence for a recessive form of the Romano-Ward long-QT syndrome and indicate that homozygous mutations on KVLQT1 do not invariably produce the Jervell and Lange-Nielsen syndrome. The implications of this observation prompt a reconsideration of the penetrance of different mutations responsible for LQTS and suggest that mild mutations in LQTS genes may be present among the general population and may predispose to drug-induced ventricular arrhythmias. It is becoming clear that mutations in the KVLQT1, human "ether-a-go-go" related gene, cardiac voltage-dependent sodium channel gene, minK and MiRP1 genes, respectively, are responsible for the LQT1, LQT2, LQT3, LQT5 and LQT6 variants of the Romano-Ward syndrome, characterized by autosomal dominant transmission and no deafness. The much rarer Jervell-Lange-Nielsen syndrome (with marked QT prolongation and sensorineural deafness) arises when a child inherits mutant KVLQT1 or minK alleles from both parents. In addition, some families are not linked to the known genetic loci. Cardiac voltage-dependent sodium channel gene encodes the cardiac sodium channel, and long QT syndrome (LQTS) mutations prolong action potentials by increasing inward plateau sodium current. The other mutations cause a decrease in net repolarizing current by reducing potassium currents through "dominant negative" or "loss of function" mechanisms. Polymorphic ventricular tachycardia (torsade de pointes) is thought to be initiated by early after-depolarizations in the Purkinje system and maintained by reentry in the myocardium. Clinical presentations vary with the specific gene affected and the specific mutation. Nevertheless, patients with identical mutations can also present differently, and some patients with LQTS mutations may have no manifest baseline phenotype. The question of whether the latter situation is one of high risk for administration of QT prolonging drugs or during myocardial ischemia is under active investigation. More generally, the identification of LQTS genes has provided tremendous new insights for our understanding of normal cardiac electrophysiology and its perturbation in a wide range of conditions associated with sudden death. It seems likely that the approach of applying information from the genetics of uncommon congenital syndromes to the study of common acquired diseases will be an increasingly important one in the next millennium. Once limited to discussions of the Jervell and Lange-Nielsen syndrome and Romano-Ward syndrome, the long QT syndrome (LQTS) is now understood to be a collection of genetically distinct arrhythmogenic cardiovascular disorders resulting from mutations in fundamental cardiac ion channels that orchestrate the action potential of the human heart. Our understanding of this genetic "channelopathy" has increased dramatically from electrocardiographic depictions of marked QT interval prolongation and torsades de pointes and clinical descriptions of people experiencing syncope and sudden death to molecular revelations in the 1990s of perturbed ion channel genes. More than 35 mutations in four cardiac ion channel genes--KVLQT1 (voltage-gated K channel gene causing one of the autosomal dominant forms of LQTS) (LQT1), HERG (human ether-a-go-go related gene.) (LQT2), SCN5A (LQT3), and KCNE1 (minK, LQT5)--have been identified in LQTS. These genes encode ion channels responsible for three of the fundamental ionic currents in the cardiac action potential. These exciting molecular break-throughs have provided new opportunities for translational research with investigations into genotype-phenotype correlations and gene-targeted therapies. Hereditary long QT syndrome (LQTS) is a cardiovascular disorder characterized by prolongation of the QT interval on the surface ECG and a high risk for arrhythmia-related sudden death. Mutations in a cardiac voltage-gated potassium channel, KCNQ1, account for the most common form of LQTS, LQTS1. The objective of this study was the characterization of a novel KCNQ1 mutation linked to LQTS. Electrophysiological properties and clinical features were determined and compared to characteristics of a different mutation at the same position. Single-strand conformation polymorphism analysis followed by direct sequencing was performed to screen LQTS genes for mutations. A novel missense mutation in the KCNQ1 gene, KCNQ1 P320H, was identified in the index patient presenting with recurrent syncope and aborted sudden death triggered by physical stress and swimming. Electrophysiological analyses of KCNQ1 P320H and the previously reported KCNQ1 P320A mutation indicate that both channels are non-functional and suppress wild type I(Ks) in a dominant-negative fashion. Based on homology modeling of the KCNQ1 channel pore region, we speculate that the proline residue at position 320 limits flexibility of the outer pore and is required to maintain the functional architecture of the selectivity filter/pore helix arrangement. Our observations on the KCNQ1 P320H mutation are consistent with previous studies indicating that pore mutations in potassium channel alpha-subunits are associated with more severe electrophysiological and clinical phenotypes than mutations in other regions of these proteins. This study emphasizes the significance of mutation screening for diagnosis, risk-assessment, and mutation-site specific management in LQTS patients. Romano-Ward syndrome is an autosomal dominant long-QT syndrome (LQTS) that predisposes affected individuals to sudden death from tachyarrhythmias. We investigated the molecular basis of LQTS in a Taiwanese kindred. Clinical and genetic analyses revealed that a mutation was linked to the human ether-a-go-go-related gene (HERG). The coding sequences and exon-intron borders of HERG were amplified by means of polymerase chain reaction and subjected to single-strand conformation polymorphism (SSCP) analysis. An exon with an aberrant SSCP pattern was cloned and sequenced to study the molecular lesion. A C-->T transition in codon 614, leading to substitution of a valine for an alanine residue in the pore region of the HERG protein, was identified. Analysis with Bsp12861 endonuclease digestion showed the mutation to be present in all affected family members. Given that an unaffected paternal uncle had inherited the same allele from the grandfather as the proband's father, a de novo mutation had apparently occurred in the father and was transmitted to his offspring. In addition to offering presymptomatic genetic diagnosis, identification of the disease-causing mutation may suggest new therapeutic approaches for treatment and prevention of this cardiovascular disease. OBJECTIVE: Hereditary long QT syndrome (LQTS) is a genetically heterogeneous disease characterized by prolonged QT intervals and an increased risk for ventricular arrhythmias and sudden cardiac death. Mutations in the voltage-gated potassium channel subunit KCNQ1 induce the most common form of LQTS. KCNQ1 is associated with two different entities of LQTS, the autosomal-dominant Romano-Ward syndrome (RWS), and the autosomal-recessive Jervell and Lange-Nielsen syndrome (JLNS) characterized by bilateral deafness in addition to cardiac arrhythmias. In this study, we investigate and discuss dominant-negative I(Ks) current reduction by a KCNQ1 deletion mutation identified in a RWS family. METHODS: Single-strand conformation polymorphism analysis and direct sequencing were used to screen LQTS genes for mutations. Mutant KCNQ1 channels were heterologously expressed in Xenopus oocytes, and potassium currents were recorded using the two-microelectrode voltage clamp technique. RESULTS: A heterozygous deletion of three nucleotides (CTT) identified in the KCNQ1 gene caused the loss of a single phenylalanine residue at position 339 (KCNQ1-deltaF339). Electrophysiological measurements in the presence and absence of the regulatory beta-subunit KCNE1 revealed that mutant and wild type forms of an N-terminal truncated KCNQ1 subunit (isoform 2) caused much stronger dominant-negative current reduction than the mutant form of the full-length KCNQ1 subunit (isoform 1). CONCLUSION: This study highlights the functional relevance of the truncated KCNQ1 splice variant (isoform 2) in establishment and mode of inheritance in long QT syndrome. In the RWS family presented here, the autosomal-dominant trait is caused by multiple dominant-negative effects provoked by heteromultimeric channels formed by wild type and mutant KCNQ1-isoforms in combination with KCNE1. The Department of Pediatric Cardiology, Medical University of Silesia in Katowice-Ligota, studied 24 patients with clinically diagnosed (using ECG) long-QT syndrome (LQTS) in 18 cases. Nine patients were diagnosed with LQT1 and nine with LQT2. The other six individuals were healthy, with no symptoms characteristic for prolonged QT syndrome, but came from families with confirmed disease occurrence. The study was conducted on members of four families. In order to search for mutations (using mSSCP and sequencing), genomic DNA was obtained from patients to determine the expression levels of the genes KCNQ1 and KCNH2 (HERG), involved in the occurrence of clinical signs of disease. Total RNA was extracted from peripheral blood. Consent to the use of blood samples of patients had been given by the Bioethics Commission of the Medical University of Silesia. mSSCP analysis and sequencing did not confirm the occurrence of mutations in KCNQ1 and HERG associated with the occurrence of LQTS. Analysis of gene expression profile of KCNQ1 and HERG confirmed the presence of disease in people with a known clinical diagnosis. Overexpression, as well as reduced expression, was observed for the examined genes. KCNQ1 was inhibited in two families, whereas HERG was reduced in one and overexpressed in the other. Gene expression profile analysis showed abnormal expressions of KCNQ1 and HERG in healthy subjects, which may be a sign of predisposition to develop the disease. The novelty of our study involved the use of total mRNA isolated from human peripheral blood, and the very limited evidence in the literature to date regarding the assessment of gene expression profile of HERG and KCNQ1 in relation to the presence of prolonged QT syndrome. |
355 | Does melanoma occur in people of African origin ? | Yes. Africans with dark skin have a reduced risk of getting all types of skin cancer as compared with Caucasians. The incidence of malignant melanoma in Johannesburg Black was 1,2 per 100 000 and accounted for 2% of all cancers. The largest number of cases occurred in the 50- 70-year age group and there was a female preponderance. As in previous studies, the sites predominantly affected were the foot and the hand, mainly on the plantar and palmar surfaces. | [876685, 8000657, 10461463, 15540891, 97949, 19450404, 5776549, 12883369, 8402099, 20415670, 475965, 19538377, 8260178, 1135705, 1138394, 11205232, 1156726, 18227705, 1920508] | 462 | Hutchinson's melanotic freckle (lentigo maligna) is a well-known pigmented lesion, usually seen on the face of white patients. It may be associated with invasive malignant melanoma. This paper reports the incidence of this lesion in association with invasive malignant melanomas of the feet and hands of Black Africans. In Blacks, as in Whites, malignant melanoma with adjacent Hutchinson's melanotic freckle carries a considerably better prognosis than other histogenetic patterns of malignant melanoma. BACKGROUND: Scant data exists on melanoma in blacks from Africa. This study was undertaken to define factors affecting outcome of blacks from South Africa with melanoma. STUDY DESIGN: A retrospective analysis of the management and outcome of 63 black patients with malignant melanoma treated at a major referral center during a 14 year period is presented. Data evaluated included patient demographic and clinical characteristics, stage at presentation, tumor site, histologic type, treatment, and subsequent cure. Survival curves were calculated for stage and site of disease. RESULT: The mean age at presentation of the 39 women and 24 men was 60.5 years (range of 30 to 85 years), with a peak incidence in the sixth decade. The foot was the most common site of disease (45 patients). Seven patients had subungual melanoma, seven had primary mucosal lesions, and in six, the primary lesion could not be found. Thirty patients presented with stage I disease, two with stage II, 23 with stage III, and nine with disseminated metastatic disease. Acral lentiginous melanoma was the most common histogenetic type (34 patients), nodular melanoma occurred in ten patients, and superficial spreading melanoma occurred in three patients. The mean Breslow depth was 6.15 mm (range of 1 to 25 mm). Patients with localized disease were treated by wide local excision and split skin graft, while patients with melanoma in the nailbed were treated by amputation of the involved digit. Sixteen patients are alive after a mean follow-up period of 82.1 months, 44 have died after a mean of 12.7 months, and five patients have been unavailable for follow-up evaluation. CONCLUSIONS: The poor prognosis in black patients in South Africa is the result of delayed presentation with thick primary lesions and advanced disease. An active education program may reduce mortality by detecting the disease earlier. Malignant melanoma (MM) remains a pediatric rarity world-wide, but perhaps more so in black Africans. To the best of our knowledge, the current report of MM in a two-and-a-half-year-old Nigerian who had a pre-existing congenital giant hairy nevus is probably the first (in an accessible literature) in a black African child. Primary neoplastic transformation and metastatic spread were suggested by the appearance of multiple swellings over the "garment" precursor nevus at the posterior trunk, multiple ipsilateral axillary nodal enlargement, and fresh occipital swellings postadmission. Smaller-sized hyperpigmented lesions with irregular, nonlobulated, and frequently hairy surfaces were also discernible over the upper and lower extremities, but the face, anterior trunk, and mucosal surfaces were relatively spared. A diagnosis of MM was confirmed by the subsequent histopathologic findings from the fine-needle aspirate and biopsy specimens. Chemotherapy was initiated but was truncated shortly after by parent-pressured discharge. Despite the rarity of MM in a tropical African setting where management options are few, the current case underscores the need for a high clinical index of diagnostic suspicion, an early pursuit of investigative confirmation, and prophylactic excision in children with the predisposing skin lesions, like congenital giant hairy nevus. An expounded discourse of the possible precursors and management options of MM is provided. We emphasize the need for institutional cost subsidy for anticancer care in tropical children. Globally, cutaneous cancers are among the most common form of cancer. Among Africans, there are significant differences in the types of skin cancer compared to those documented in patients from other countries. We evaluated all the patients with a histological diagnosis of skin cancer presenting to the University of Calabar Teaching Hospital from January 2005 through December 2006. Twenty-nine patients (18 males and 11 females) with skin cancer were identified and these accounted for 8.0 percent of total malignancies. Their ages ranged from 16 to 70 years (mean 43.5 years). Kaposi sarcoma (KS) was the most common skin cancer. Kaposi sarcoma associated with HIV represented 81.8 percent of KS cases found. Squamous cell carcinoma (SCC) ranked second and malignant melanoma third. Of the skin cancers in our series, the most common site was the lower limb (55.2%), followed by the head and neck (24%). The 4 albinos accounted for 13.8 percent of the skin cancers found. Immunosuppression (KS), chronic ulcer, inflammation, albinism, and solar radiation were identified risk factors. Public education strategies on prevention, with an emphasis on early identification and surgical treatment of skin cancers are urged. In addition, treatment of and close observation of chronic ulcers are recommended. A case of leptomeningeal melanoma in an African child of 7 years is presented together with a survey of pigmentation in the normal African brain. There is a direct relationship between the depth of pigment of the leptomeninges and the skin in Ugandan Africans, suggesting that similar factors operate in the control of melanocytes in these two sites. Little is known about the behaviour of melanoma in patients of mixed ancestry. A retrospective analysis of 844 consecutive patients presenting with melanoma over a 12-year period was performed. Forty patients (4.8%) were of mixed ancestry. The data evaluated included patient age, gender, delay in presentation, presenting stage, anatomical distribution, histology, management and outcome. The mean age at presentation was 52.8 years. Twenty-seven patients were female. The mean delay in presentation was 1.54 years. Seventy per cent of melanomas were confined to the extremities, of which one-third were plantar in origin. The most common histological variant, affecting 13 patients (32.5%), was acral lentiginous melanoma; 12.5% of patients presented with in situ (Stage 0) disease, 17.5% with Stage I disease, 22.5% with Stage II disease, 27.5% with Stage III disease and 7.5% with Stage IV disease. Twenty-seven patients (67.5%) remained alive at the end of the study after a median follow-up of 5.58 years, whilst 11 (27.5%) died after a median of 2.42 years. The median survival was 3.92 years. Although the histological type and anatomical distribution reflect the disease pattern of black populations, the overall 5-year survival of 74% is similar to that seen in white populations. An education programme is needed to improve melanoma awareness in mixed race populations. The outcome of treatment in 40 black patients (27 women, 13 men; mean age 62.9 years) with plantar melanoma over a 13-year period was analysed to evaluate the efficacy of wide local excision with split skin grafting. Substantial delay in seeking medical attention occurred in 35 patients. At presentation, 20 patients had stage I disease, one stage II, 15 stage III and four stage IV. Acral lentiginous melanoma (27 patients) was the most common histological type. The mean Breslow depth was 6.9 mm and 35 patients had lesions of Clark level IV or V. The mean surface area or plantar lesions was 13.3 cm2. Wide local excision with split skin grafting was used in 29 patients; four patients with neglected advanced plantar lesions had below-knee amputation and seven with metastatic disease did not undergo surgery. Graft sepsis occurred in six patients and local recurrence in two. Nine patients were alive at follow-up; the 5-year survival rate was 25 per cent. Delay in presentation and locally advanced disease may explain the poor prognosis of plantar melanoma in black South Africans. The incidences of malignant melanoma recorded by 59 population-based cancer registries were investigated to determine the effects of racial and skin-colour differences. White populations exhibited a wide range of melanoma incidences and females commonly, though not invariably, had a higher incidence than males. Non-white populations experienced in general a much lower incidence of melanoma although there was some overlap of white and non-white rates. No predominant sex difference emerged among non-whites. Populations of African descent were found to have a higher incidence than those of Asiatic origin, but it was concluded that this was due largely to the high frequency of tumours among Africans on the sole of the foot. A clear negative correlation between degree of skin pigmentation and melanoma incidence emerged for the exposed body sites. These data provide strong support for the hypotheses that UV radiation is a major cause of malignant melanoma and that melanin pigmentation protects against it. Further research is required to elucidate the aetiology of melanoma of the sole of the foot. BACKGROUND: Albinism is an established risk factor for skin cancer in black Africans, and high levels of ultraviolet radiation increase the risk of the three major forms of skin cancer. METHODS: We present four albinos with histologic diagnoses of skin cancer who were seen at the University of Calabar Teaching Hospital, Calabar, Nigeria from January 2005 to December 2006. Skin cancer in these cases was compared with the total skin cancer affecting 29 patients during the study period. RESULTS: Twenty-nine patients presented with skin cancer during the study period. Four Nigerian albinos (two men and two women) with skin cancer accounted for 13.8% of the skin cancers observed during the 2-year period. They ranged in age from 22 to 40 years (mean, 27.8 years). The sites of the lesions included the head [squamous cell carcinoma (SCC) in two patients and basal cell carcinoma (BCC) in one patient] and the upper limb (melanoma). All tumors were excised; in addition, patients with SCC and melanoma received adjuvant chemotherapy. Two patients, one woman with SCC and the patient with melanoma, showed residual tumor because of inadequate excision. During the evaluation period between 14 and 18 months, the sites appeared to be healed with no evidence of recurrence in the male with SCC and female with BCC. CONCLUSION: Albinism and solar radiation are risk factors for skin cancer. Early implementation of public education strategies on prevention should improve outcome. A review of 775 normally pigmented Africans and 18 African albinos with malignant skin tumours showed that squamous cell carcinoma was the most common tumour type, in contrast to Caucasians, in whom basal cell carcinoma is most frequent. In African albinos squamous cell carcinoma of the head and neck region was most frequent. However, the proportion of basal cell carcinomas was low also among albinos but higher than among normally pigmented patients. In contrast to the normally pigmented patients, there were no squamous cell carcinomas on the limbs in albino patients. We suggest that this difference was due to environmental factors, such as chronic leg ulcers, which might have been less influential in the albinos, who seldom lived more than 30 years. No cases of cutaneous melanoma or Kaposi sarcoma were found in the albino group. Malignant melanoma of the skin in Blacks in formidable and sinister tumour. This study is concerned with the epidemiology of malignant melanoma, as seen in both urban and rural Black Africans. A smaller series in which follow-up on the patients was available is included. To our knowledge, this is the first study of its kind in which follow-up, and hence survival figures, can be quoted. Although the numbers are relatively small, they provide a valuable indication of the behaviour of melanomas in this group. The difficulties of follow-up cannot be overemphasised, and follow-up on 79 cases out of 100 could be obtained only by the employment of an able and enthusiastic Black social worker for 3 years. The first recorded survival figures in a Black population show a 3-year survival rate of only 28,4%. Prognosis is related to the size and extent of the tumour with larger and more widespread tumours faring worse than others. The incidence of malignant melanoma in Johannesburg Black was 1,2 per 100 000 and accounted for 2% of all cancers. The largest number of cases occurred in the 50- 70-year age group and there was a female preponderance. As in previous studies, the sites predominantly affected were the foot and the hand, mainly on the plantar and palmar surfaces. Follow-up data (over a 3-year period) and the histological appearances of primary lesion were studied and related in 40 Black patients with malignant melanoma. This to our knowledge is the first study in Black African patients. It was found that they present with large deeply invasive lesions, particularly on the foot. The prognosis is poor, with an over-all 3-year survival rate of 35%. The histological features used to assess the prognosis of malignant melanoma in Whites, that is histogenetic pattern, size and shape of the lesion, level of invasion, presence of ulceration and mitotic activity would seem to be equally applicable in Black patients. In addition, marked cellular pleomorphism, haemorrhage, necrosis and fibrosis within the tumour are bad signs. In this series lymphocytic infiltration, either within the tumour or at the edge, possibly indicative of an immune response, seemed to be of favourable prognostic import. Surprisingly, a lesion histologica-ly that of lentigo maligna melanoma was found on the feer of some blacks and could be related to much more favourable survival figures. Malignant melanomas in black Africans are predominantly located on the lower extremities. Since their biological features have not been well focused, we studied 28 such cases with special reference to proliferative activity (Ki-67 expression), p16 and p53 staining, as well as microvessel density, all known to be involved in the progression of melanomas among whites. The findings were related to clinico-pathological characteristics. The tumours had a median thickness of 6.4 mm, ulceration was present in 71%, and vascular invasion in 36%, indicating the presence of advanced and aggressive melanomas. Further, loss of p16 protein expression was found in 50%, and high proliferative activity was present (median 41%). In contrast, strong p53 staining was rare (11%), although most tumours showed low-level positivity. Angiogenesis, as estimated by microvessel density, was significantly associated with vascular invasion (p = 0.022), supporting its role in the progression of these tumours. Thus, our findings indicate that melanomas located on the lower extremities in black Africans show several features of aggressiveness; in particular, the proliferative activity was high, and p16 alterations was frequent as evidenced by loss of protein staining. Our findings also indicated that the diagnosis is delayed among black Africans. Earlier studies have shown frequent mutations in the BRAF and NRAS genes in cutaneous melanoma, but these alterations have not been examined in the rare category of melanoma from black Africans. Moreover, the frequency of epidermal growth factor receptor (EGFR) mutations in melanocytic tumors is not known. We therefore examined 165 benign and malignant melanocytic lesions (including 118 invasive melanomas and 18 metastases collected as consecutive cases from various time periods and from two different pathology departments; the 51 nodular melanomas were randomly selected from a larger, consecutive, population-based series of nodular melanomas) with respect to alterations in the EGFR, BRAF and NRAS genes. Mutations in EGFR (exons 18-21) were not detected. EGFR protein expression was observed in a subgroup of melanomas, but without associations with clinicopathologic phenotype or prognosis. Cytoplasmic EGFR expression was, however, significantly increased from benign nevi to melanomas. Mutations in BRAF and NRAS were detected in superficial melanoma (25 and 29%, respectively), nodular melanoma (29 and 28%, respectively) and lentigo maligna melanoma (15 and 16%, respectively). In a series of melanomas from black Africans (n=26), only two BRAF mutations (8%) were found, both being different from the common T1799A substitution. Moreover, melanomas from black Africans exhibited mutations in NRAS exon 1 only (12%), whereas NRAS exon 2 mutations were predominant in melanomas from Caucasians. Thus, the frequencies of BRAF and NRAS mutations were particularly low in melanomas from black Africans, supporting a different pathogenesis of these tumors. Skin cancers, although uncommon, do occur in black Africans. Available literature on this subject from black African populations is scant, suggesting diminished interest. Eighteen cases of malignant skin tumors seen at the University of Port Harcourt Teaching Hospital over 3 years (1984 to 1987) were analyzed for diagnoses, site of tumors, sex, and age. Seven patients (39%) had malignant melanomas affecting only the soles of the feet, while the same number had squamous cell carcinomas widely distributed in various parts of the body. Basal cell carcinomas were found in four (22%) patients with face lesions. Only three albinos were in the series, and all three had squamous cell carcinomas. Melanin protection against sun-induced skin cancers gives a false sense of well-being. The need for renewed interest of the subject is emphasized. |
356 | What is the effect of resveratrol on mTOR activity? | Resveratrol (RSV) inhibits leucine-stimulated mTORC1 activation by promoting mTOR/DEPTOR. | [19108833, 21179458, 23248098, 19827268, 22269797, 21168265, 23272906, 23211629, 19471118, 22029423, 22530672, 20169165, 22242130, 20851890, 25448084, 24060150, 21966552, 23680031] | 463 | BACKGROUND: Resveratrol, a naturally occurring phytopolyphenol compound, has attracted extensive interest in recent years because of its diverse pharmacological characteristics. Although resveratrol possesses chemopreventive properties against several cancers, the molecular mechanisms by which it inhibits cell growth and induces apoptosis have not been clearly understood. The present study was carried out to examine whether PI3K/AKT/FOXO pathway mediates the biological effects of resveratrol. METHODOLOGY/PRINCIPAL FINDINGS: Resveratrol inhibited the phosphorylation of PI3K, AKT and mTOR. Resveratrol, PI3K inhibitors (LY294002 and Wortmannin) and AKT inhibitor alone slightly induced apoptosis in LNCaP cells. These inhibitors further enhanced the apoptosis-inducing potential of resveratrol. Overexpression of wild-type PTEN slightly induced apoptosis. Wild type PTEN and PTEN-G129E enhanced resveratrol-induced apoptosis, whereas PTEN-G129R had no effect on proapoptotic effects of resveratrol. Furthermore, apoptosis-inducing potential of resveratrol was enhanced by dominant negative AKT, and inhibited by wild-type AKT and constitutively active AKT. Resveratrol has no effect on the expression of FKHR, FKHRL1 and AFX genes. The inhibition of FOXO phosphorylation by resveratrol resulted in its nuclear translocation, DNA binding and transcriptional activity. The inhibition of PI3K/AKT pathway induced FOXO transcriptional activity resulting in induction of Bim, TRAIL, p27/KIP1, DR4 and DR5, and inhibition of cyclin D1. Similarly, resveratrol-induced FOXO transcriptional activity was further enhanced when activation of PI3K/AKT pathway was blocked. Over-expression of phosphorylation deficient mutants of FOXO proteins (FOXO1-TM, FOXO3A-TM and FOXO4-TM) induced FOXO transcriptional activity, which was further enhanced by resveratrol. Inhibition of FOXO transcription factors by shRNA blocked resveratrol-induced upregulation of Bim, TRAIL, DR4, DR5, p27/KIP1 and apoptosis, and inhibition of cyclin D1 by resveratrol. CONCLUSION/SIGNIFICANCE: These data suggest that FOXO transcription factors mediate anti-proliferative and pro-apoptotic effects of resveratrol, in part due to activation of extrinsic apoptosis pathway. SIRT1 (mammalian ortholog of the yeast silent information regulator 2) is a NAD-dependent histone deacetylase belonging to the multigene family of sirtuins. Anecdotal and epidemiologic observations provide evidence for beneficial effects of the calorie restriction mimetic resveratrol (RES), a SIRT1 activator in preventing cardiovascular diseases and cancer. Although SIRT1 possesses both tumorigenic and antitumorigenic potential, the molecular mechanisms underlying SIRT1-mediated tumor progression or inhibition are poorly understood. In this study, we investigated the role of SIRT1 in multiple human prostate cancer cell lines and prostate-specific PTEN knockout mouse model using resveratrol. Androgen-independent prostate cancer cell lines (C42B, PC3, and DU145) express higher levels of SIRT1 than androgen-responsive (LNCaP) and nontumorigenic prostate cells (RWPE-1). Resveratrol enhanced this expression without any significant effect on SIRT1 enzymatic activity. Inhibition of SIRT1 expression using shRNA enhanced cell proliferation and inhibited autophagy by repressing phosphorylation of S6K and 4E-BP1. These biologic correlates were reversed in the presence of resveratrol. Analysis of prostates from dietary intervention with resveratrol showed a significant reduction in prostate weight and reduction in the incidence of high-grade prostatic intraepithelial neoplastic (HGPIN) lesions by approximately 54% with no significant change in body weight. Consistent with the in vitro findings, resveratrol intervention in the PTEN knockout mouse model was associated with reduction in the prostatic levels of mTOR complex 1 (mTORC1) activity and increased expression of SIRT1. These data suggest that SIRT1/S6K-mediated inhibition of autophagy drives prostate tumorigenesis. Therefore, modulation of SIRT1/S6K signaling represents an effective strategy for prostate cancer prevention. Resveratrol (trans-3,4', 5-trihydroxystilbene) is a naturally occurring polyphenolic compound that has antiinflammatory, antioxidant, neuroprotective properties and acts as a chemopreventive agent. Resveratrol causes cell cycle arrest and induces apoptotic cell death in various types of cancer cells. In the current studies, the effect of resveratrol on phosphoinositide kinase-3 (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway was examined in human U251 glioma cells. Resveratrol decreased both the expression and phosphorylation of Akt. Inhibitors of PI3K (LY294002) and Akt (SH-6) enhanced resveratrol-induced LDH release and caspase-3 activation. Resveratrol reduced phosphorylation of ribosomal protein S6 and the mTOR inhibitor rapamycin further enhanced resveratrol-induced cell death. These results suggest that the downregulation of PI3K/Akt/mTOR signaling pathways may be an important mediator in resveratrol-induced apoptosis in glioma cells. The anti-tumor activity of rapamycin is compromised by the feedback-loop-relevant hyperactive PI3K and ERK-MAPK pathway signaling. In breast cancer cells treated with rapamycin, we observed a moderate increase of AKT phosphorylation (P-AKT) in a rapamycin resistant cell line, MDA-MB-231, as well as a slight increase of P-AKT in a rapamycin sensitive cell line, MCF-7. We found that resveratrol, a natural phytoalexin, suppressed the phosphorylation and activation of the PI3K/AKT pathway in all the three breast cancer cell lines that we tested. It also had a weak inhibitory effect on the activation of the mTOR/p70S6K pathway in two cell lines expressing wildtype PTEN, MCF-7 and MDA-MB-231. The combined use of resveratrol and rapamycin resulted in modest additive inhibitory effects on the growth of breast cancer cells, mainly through suppressing rapamycin-induced AKT activation. We, therefore, reveal a novel combination whereby resveratrol potentiates the growth inhibitory effect of rapamycin, with the added benefit of preventing eventual resistance to rapamycin, likely by suppressing AKT signaling. We also present data herein that PTEN is an important contributor to resveratrol's growth suppressive effects and its potentiation of rapamycin in this therapeutic scenario, as resveratrol's suppression of rapamycin-mediated induction of P-AKT is both PTEN-dependent and -independent. Thus, the resveratrol-rapamycin combination may have therapeutic value in treating breast cancer and perhaps other processes where mTOR is activated. Resveratrol (3,4',5-trihydroxystilbene; RSV), a natural polyphenol found in a variety of daily food including grapes and red wine, has long been suspected to have multifaceted health beneficial properties, including anti-inflammation, anti-oxidant, and anticancer activities. Over the past few years, numerous studies have suggested that suppressing the activity of mammalian target of rapamycin (mTOR), a critical regulator of cell metabolism, growth, and proliferation, may provide a key mechanism underlying the anticarcinogenic properties of resveratrol. It has been found that resveratrol targets multiple components of the phosphatidylinositol 3- kinase(PI3K)/Akt and mTOR signaling pathways, including PI3K, Akt, PTEN, and DEPTOR, suggesting that this natural compound and its derivatives may offer a promising new cancer treatment. In the current review, we discuss recent findings on the molecular mechanisms regulating mTOR signaling and the therapeutic potential of resveratrol for cancer treatment by targeting mTOR. Resveratrol is indicated to be involved in neuroprotection and anti-inflammation in epileptic rats. The molecular mechanism is still not fully understood. In this study, we investigated the role of resveratrol in nuclear factor-kappa B associated inflammatory responses induced by status epilepticus. Our data showed that seizures activated mammalian target of rapamycin (mTOR), increased the activity of nuclear factor-kappa B and promoted the expressions of inflammatory molecules including inducible nitric oxide synthase, cyclooxygenase-2 and interleukin-1β. Futhermore, resveratrol significantly inhibited the activation of nuclear factor-kappa B and the production of proinflammatory molecules via mTOR pathway. Additionally, we also proved that the inhibition of mTOR signal by resveratrol was mostly attributed to AMP-activated kinase (AMPK) activation. Altogether, our results suggest that resveratrol suppresses inflammatory responses induced by seizures partially via AMPK/mTOR pathway. Here we demonstrated that, at cytostatic, near-toxic concentrations, resveratrol inhibited S6 phosphorylation and prevented the senescence morphology in human cells. Using a sensitive functional assay, we found that resveratrol partially prevented loss of the proliferative potential associated with cellular senescence. Resveratrol was less effective than rapamycin, because aging-suppression by resveratrol was limited by its toxicity at high concentrations. We discuss whether concentrations of resveratrol that inhibit mTOR (target of rapamycin) and suppress cellular senescence are clinically achievable and whether partial inhibition of mTOR by resveratrol might be sufficient to affect organismal aging. BACKGROUND: Prostate cancer (PrCa) displays resistance to radiotherapy (RT) and requires radiotherapy dose escalation which is associated with greater toxicity. This highlights a need to develop radiation sensitizers to improve the efficacy of RT in PrCa. Ionizing radiation (IR) stimulates pathways of IR-resistance and survival mediated by the protein kinase Akt but it also activates the metabolic energy sensor and tumor suppressor AMP-Activated Protein Kinase (AMPK). Here, we examined the effects of the polyphenol resveratrol (RSV) on the IR-induced inhibition of cell survival, modulation of cell cycle and molecular responses in PrCa cells. METHODS: Androgen-insensitive (PC3), sensitive (22RV1) PrCa and PNT1A normal prostate epithelial cells were treated with RSV alone (2.5-10 μM) or in combination with IR (2-8 Gy). Clonogenic assays, cell cycle analysis, microscopy and immunoblotting were performed to assess survival, cell cycle progression and molecular responses. RESULTS: RSV (2.5-5 μM) inhibited clonogenic survival of PC3 and 22RV1 cells but not of normal prostate PNT1A cells. RSV specifically sensitized PrCa cells to IR, induced cell cycle arrest at G1-S phase and enhanced IR-induced nuclear aberrations and apoptosis. RSV enhanced IR-induced expression of DNA damage (γH2Ax) and apoptosis (cleaved-caspase 3) markers as well as of the cell cycle regulators p53, p21(cip1) and p27(kip1). RSV enhanced IR-activation of ATM and AMPK but inhibited basal and IR-induced phosphorylation of Akt. CONCLUSIONS: Our results suggest that RSV arrests cell cycle, promotes apoptosis and sensitizes PrCa cells to IR likely through a desirable dual action to activate the ATM-AMPK-p53-p21(cip1)/p27(kip1) and inhibit the Akt signalling pathways. Resveratrol is a plant-derived polyphenol that extends lifespan and healthspan in model organism. Despite extensive investigation, the biological processes mediating resveratrol's effects have yet to be elucidated. Because repression of translation shares many of resveratrol's beneficial effects, we hypothesized that resveratrol was a modulator of protein synthesis. We studied the effect of the drug on the H4-II-E rat hepatoma cell line. Initial studies showed that resveratrol inhibited global protein synthesis. Given the role of the mammalian Target of Rapamycin (mTOR) in regulating protein synthesis, we examined the effect of resveratrol on mTOR signaling. Resveratrol inhibited mTOR self-phosphorylation and the phosphorylation of mTOR targets S6K1 and eIF4E-BP1. It attenuated the formation of the translation initiation complex eIF4F and increased the phosphorylation of eIF2α. The latter event, also a mechanism for translation inhibition, was not recapitulated by mTOR inhibitors. The effects on mTOR signaling were independent of effects on AMP-activated kinase or AKT. We conclude that resveratrol is an inhibitor of global protein synthesis, and that this effect is mediated through modulation of mTOR-dependent and independent signaling. Resveratrol (RSV) is a naturally occurring polyphenol that has been found to exert antioxidant, anti-inflammatory, and neuroprotective properties. However, how RSV exerts its beneficial health effects remains largely unknown. Here, we show that RSV inhibits insulin- and leucine-stimulated mTOR signaling in C2C12 fibroblasts via a Sirt1-independent mechanism. Treating C2C12 cells with RSV dramatically inhibited insulin-stimulated Akt, S6 kinase, and 4E-BP1 phosphorylation but had little effect on tyrosine phosphorylation of the insulin receptor and activation of the p44/42 MAPK signaling pathway. RSV treatment also partially blocked mTOR and S6 kinase phosphorylation in TSC1/2-deficient mouse embryonic fibroblasts, suggesting the presence of an inhibitory site downstream of TSC1/2. Knocking out PDK1 or suppressing AMP-activated protein kinase had little effect on leucine-stimulated mTOR signaling. On the other hand, RSV significantly increased the association between mTOR and its inhibitor, DEPTOR. Furthermore, the inhibitory effect of RSV on leucine-stimulated mTOR signaling was greatly reduced in cells in which the expression levels of DEPTOR were suppressed by RNAi. Taken together, our studies reveal that RSV inhibits leucine-stimulated mTORC1 activation by promoting mTOR/DEPTOR interaction and thus uncover a novel mechanism by which RSV negatively regulates mTOR activity. In breast cancer cells, overexpression of human epidermal growth factor receptor 2 (HER2) increases the translation of fatty acid synthase (FASN) by altering the activity of PI3K/Akt signaling pathways. Cancer chemotherapy causes major side effects and is not effective enough in slowing down the progression of the disease. Earlier studies showed a role for resveratrol in the inhibition of FASN, but the molecular mechanisms of resveratrol-induced inhibition are not known. In the present study, we examined the novel mechanism of resveratrol on Her2-overexpressed breast cancer cells. The effect of resveratrol on the growth of breast cancer cells was assessed as percent cell viability by cytotoxicity-based MTT assay and the induction of apoptosis was determined by cell-death detection ELISA and flow cytometric analysis of Annexin-V-PI binding. Western immunobloting was used to detect signaling events in human breast cancer (SKBR-3) cells. Data showed that resveratrol-mediated down-regulation of FASN and HER2 genes synergistically induced apoptotic death in SKBR-3 cells. This concurrently caused a prominent up-regulation of PEA3, leads to down-regulation of HER2 genes. Resveratrol also alleviated the PI3K/Akt/mTOR signaling by down-regulation of Akt phosphorylation and up-regulation of PTEN expression. These findings suggest that resveratrol alters the cell cycle progression and induce cell death via FASN inhibition in HER2 positive breast cancer. Resveratrol (RSV) is a natural polyphenol produced by plants and is proposed to have multiple beneficial effects on health. In recent years, the interest in this molecule has increased nearly exponentially following the major findings that RSV (I) is chemo-preventive in some cancer models, (II) is cardio-protective and (III) has positive effects on metabolism in mammals and increases lifespan in lower organisms. Mechanistic target of rapamycin (mTOR) is a central controller of cell growth, proliferation, metabolism and angiogenesis. As a part of the mTORC1 and mTORC2 complexes, the mTOR kinase plays a key role in several pathways involved in cancer and metabolic diseases. Recent studies suggest that modulation of the mTOR signalling pathway could play an important role in mediating the beneficial effects of RSV. Therefore, this review summarises the current findings regarding RSV and its inhibition/activation of the proteins in the mTOR pathway, and thereby propose the proteins of the mTOR cascade to be primary targets for RSV. RSV affects many different targets related to mTOR, and it is not clear which is most relevant. However, most frequently, RSV is found to inhibit the activity of the mTOR pathway proteins, and to activate AMPK and LKB1, which can suppress mTOR signalling. Thus, it appears that RSV plays a role in modulation of proteins of the mTOR pathway although more research is still needed to fully understand the interaction. Resveratrol (RSV, trans-3,4,5-Trihydroxystilbene), a type of polyphenol originally found in red wines, shows a great promise for the treatment of cancer, aging, type 2 diabetes and cardiovascular diseases. Recent studies suggest that suppressing the signaling pathway mediated by mTOR, a well-known energy sensor that integrates various hormonal, nutrient and environmental signals to regulate cell growth, metabolism and survival, could play an important role in mediating the beneficial effect of RSV. The underlying mechanisms by which RSV inhibits mTOR signaling remain elusive, but our recent studies show that RSV inhibits amino acid-stimulated mTOR signaling in C2C12 fibroblasts via a Sirt1- and AMPK-independent mechanism. RSV treatment has no effect on the expression levels of mTOR, raptor and DEPTOR, but greatly promotes the interaction between mTOR and its inhibitor DEPTOR. Our results reveal a novel mechanism by which RSV inhibits mTOR signaling and its function. Resveratrol has many biological effects, including anti-tumor, antiviral activities, and vascular protection. Recent studies have suggested that resveratrol exert its antitumor effects through induction of autophagy by an unknown mechanism. In this study, we investigated the involvement of autophagy in resveratrol-induced cell death and its potential molecular mechanisms in A549 human lung adnocarcinoma cells. Resveratrol-induced growth inhibition and cell death was assessed by MTT and clonogenic assays. Activation of autophagy was characterized by monodansylcadaverine, transmission electron microscopy, and expression of autophagy marker protein LC3. Western blot analysis was used to study the cell signals involved in the mechanisms of autophagic death. Intracellular free calcium was detected with Fura2-AM staining. Our results indicated that resveratrol induced A549 cell death was mediated by autophagy. 3-methyladenine, an inhibitor of autophagy, suppressed resveratrol-induced autophagic cell death, and knockdown of autophagy-related genes Atg5 and Beclin-1 with siRNAs reversed RSV-induced cell death. Intracellular free calcium accumulated immediately following resveratrol addition, which led to the activation of phospho-AMPK and phospho-Raptor, and a reduction in the amount of phospho-p70S6K. These effects could be reversed by the AMPK inhibitor compound C, and the calcium ion-chelating agent EGTA. In conclusion, we demonstrate that resveratrol-induced A549 cell death was mediated by the process of autophagic cell death via Ca(2+)/AMPK-mTOR signaling pathway. |
357 | Are people with blood group O protected against severe Malaria? | It appears that individuals who are of blood-group O are relatively resistant to the severe disease caused by P. falciparum infection. | [17959777, 22771625, 23071435, 15814030, 22818742] | 464 | Malaria has been a major selective force on the human population, and several erythrocyte polymorphisms have evolved that confer resistance to severe malaria. Plasmodium falciparum rosetting, a parasite virulence phenotype associated with severe malaria, is reduced in blood group O erythrocytes compared with groups A, B, and AB, but the contribution of the ABO blood group system to protection against severe malaria has received little attention. We hypothesized that blood group O may confer resistance to severe falciparum malaria through the mechanism of reduced rosetting. In a matched case-control study of 567 Malian children, we found that group O was present in only 21% of severe malaria cases compared with 44-45% of uncomplicated malaria controls and healthy controls. Group O was associated with a 66% reduction in the odds of developing severe malaria compared with the non-O blood groups (odds ratio 0.34, 95% confidence interval 0.19-0.61, P < 0.0005, severe cases versus uncomplicated malaria controls). In the same sample set, P. falciparum rosetting was reduced in parasite isolates from group O children compared with isolates from the non-O blood groups (P = 0.003, Kruskal-Wallis test). Statistical analysis indicated a significant interaction between host ABO blood group and parasite rosette frequency that supports the hypothesis that the protective effect of group O operates through the mechanism of reduced P. falciparum rosetting. This work provides insights into malaria pathogenesis and suggests that the selective pressure imposed by malaria may contribute to the variable global distribution of ABO blood groups in the human population. Erythrocyte polymorphisms associated with a survival advantage to Plasmodium falciparum infection have undergone positive selection. There is a predominance of blood group O in malaria-endemic regions, and several lines of evidence suggest that ABO blood groups may influence the outcome of P. falciparum infection. Based on the hypothesis that enhanced innate clearance of infected polymorphic erythrocytes is associated with protection from severe malaria, we investigated whether P. falciparum-infected O erythrocytes are more efficiently cleared by macrophages than infected A and B erythrocytes. We show that human macrophages in vitro and mouse monocytes in vivo phagocytose P. falciparum-infected O erythrocytes more avidly than infected A and B erythrocytes and that uptake is associated with increased hemichrome deposition and high molecular weight band 3 aggregates in infected O erythrocytes. Using infected A(1), A(2), and O erythrocytes, we demonstrate an inverse association of phagocytic capacity with the amount of A antigen on the surface of infected erythrocytes. Finally, we report that enzymatic conversion of B erythrocytes to type as O before infection significantly enhances their uptake by macrophages to observed level comparable to that with infected O wild-type erythrocytes. These data provide the first evidence that ABO blood group antigens influence macrophage clearance of P. falciparum-infected erythrocytes and suggest an additional mechanism by which blood group O may confer resistance to severe malaria. Although the ABO blood group of the human host has been reported to influence malarial infection, there have been few clinical observations on this effect. A hospital-based, comparative study was therefore performed to investigate the relationship between blood-group type and severe disease i nPlasmodium falciparum malaria. Overall, 243 cases of malaria (163 uncomplicated and 80 severe) and 65 patients with severe, non-malarial infections were studied. In terms of ABO-blood-group composition, the patients with severe malaria were significantly different from the patients with the uncomplicated disease (P<0.001) and also from a population control described previously (P<0.0001). The patients with uncomplicated malaria or severe but non-malarial disease were, however, similar to the population control. The cases of severe malaria were significantly less likely to be of blood group O (P=0.0003), and significantly more likely to be of group AB (P<0.0001), than the patients with nonsevere malaria. It appears that individuals who are of blood-group O are relatively resistant to the severe disease caused by P. falciparum infection. There is increasing evidence that the ABO blood group phenotypes modulates Plasmodium falciparum rosetting and may influence the clinical manifestation of severe malaria. Whether blood group phenotypes are associated with risk of severe falciparum malaria in Odisha, we analyzed 343 adult malaria patients. The results showed high prevalence of blood group B in both mild (n=110) and severe malaria (cerebral malaria [CM]; n=130 and non-cerebral severe malaria [NCSM]; n=103) categories among the non-O group and while type O is significantly associated with protection against CM, patients with type A and B group had increased risk for developing CM. Further, the strength of association for B group (p=< 0.0001) was high and has double the risk of (OR=5.0) of developing CM compared to blood group A (OR=2.5). Such findings may probably be due to strain specific blood group preferences of P. falciparum and high prevalence of B group. However, the ABO blood group distribution of mild malaria was comparable with that of the NCSM group of patients. The lack of association of ABO phenotypes with NCSM is evidence for the hypothesis that the underlying pathogenesis cascades are different in CM and NCSM clinical presentations. |
358 | Which eye condition is managed by the athens protocol? | The athens protocol (transepithelial topography-guided PRK therapeutic remodeling, combined with same-day, collagen cross-linking) was developed for the management of cornea blindness due to severe corneal scarring. | [21117539, 22347790, 24893359, 24763473, 25176050] | 465 | PURPOSE: To evaluate a series of patients with corneal ectasia after LASIK that underwent the Athens Protocol: combined topography-guided photorefractive keratectomy (PRK) to reduce or eliminate induced myopia and astigmatism followed by sequential, same-day ultraviolet A (UVA) corneal collagen cross-linking (CXL). METHODS: Thirty-two consecutive corneal ectasia cases underwent transepithelial PRK (WaveLight ALLEGRETTO) immediately followed by CXL (3 mW/cm(2)) for 30 minutes using 0.1% topical riboflavin sodium phosphate. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent, keratometry, central ultrasonic pachymetry, corneal tomography (Oculus Pentacam), and endothelial cell counts were analyzed. Mean follow-up was 27 months (range: 6 to 59 months). RESULTS: Twenty-seven of 32 eyes had an improvement in UDVA and CDVA of 20/45 or better (2.25 logMAR) at last follow-up. Four eyes showed some topographic improvement but no improvement in CDVA. One of the treated eyes required a subsequent penetrating keratoplasty. Corneal haze grade 2 was present in 2 eyes. CONCLUSIONS: Combined, same-day, topography-guided PRK and CXL appeared to offer tomographic stability, even after long-term follow-up. Only 2 of 32 eyes had corneal ectasia progression after the intervention. Seventeen of 32 eyes appeared to have improvement in UDVA and CDVA with follow-up >1.5 years. This technique may offer an alternative in the management of iatrogenic corneal ectasia. PURPOSE: To evaluate the safety and efficacy of combined transepithelial topography-guided photorefractive keratectomy (PRK) therapeutic remodeling, combined with same-day, collagen cross-linking (CXL). This protocol was used for the management of cornea blindness due to severe corneal scarring. METHODS: A 57-year-old man had severe corneal blindness in both eyes. Both corneas had significant central scars attributed to a firework explosion 45 years ago, when the patient was 12 years old. Corrected distance visual acuity (CDVA) was 20/100 both eyes (OU) with refraction: +4.00, -4.50 at 135° in the right eye and +3.50, -1.00 at 55° in the left. Respective keratometries were: 42.3, 60.4 at 17° and 35.8, 39.1 at 151.3°. Cornea transplantation was the recommendation by multiple cornea specialists as the treatment of choice. We decided prior to considering a transplant to employ the Athens Protocol (combined topography-guided partial PRK and CXL) in the right eye in February 2010 and in the left eye in September 2010. The treatment plan for both eyes was designed on the topography-guided wavelight excimer laser platform. RESULTS: Fifteen months after the right eye treatment, the right cornea had improved translucency and was topographically stable with uncorrected distance visual acuity (UDVA) 20/50 and CDVA 20/40 with refraction +0.50, -2.00 at 5°. We noted a similar outcome after similar treatment applied in the left eye with UDVA 20/50 and CDVA 20/40 with -0.50, -2.00 at 170° at the 8-month follow-up. CONCLUSION: In this case, the introduction of successful management of severe cornea abnormalities and scarring with the Athens Protocol may provide an effective alternative to other existing surgical or medical options. PURPOSE: To compare epithelial remodeling in keratoconic eyes that had photorefractive keratectomy and corneal collagen crosslinking (Athens protocol) with that in untreated keratoconic eyes and healthy eyes. SETTING: Private clinical practice, Athens, Greece. DESIGN: Comparative case series. METHODS: Fourier-domain anterior segment optical coherence tomography (AS-OCT) was used to obtain in vivo 3-dimensional epithelial thickness maps and center, superior, inferior, maximum, minimum, mean, midperipheral, and variability data. RESULTS: Group A comprised 175 treated keratoconic eyes (Athens protocol); Group B, 193 untreated keratoconic eyes; and Group C, 160 healthy eyes. The 1-year mean center epithelial thickness in Group A was 47.78 μm ± 7.36 (SD) (range 33 to 64 μm). At the first clinical visit, it was 52.09 ± 6.80 μm (range 36 to 72 μm) in Group B and 52.54 ± 3.23 μm (range 45 to 59 μm) in Group C. The mean thickness range in Group A at 1 year was -19.94 ± 7.21 μm (range -6 to -34 μm). It was -21.83 ± 12.07 μm (range -4 to -66 μm) in Group B and -6.86 ± 3.33 μm (range -3 to -29 μm) in Group C. The mean topographic thickness variability in Group A at 1 year was 4.64 ± 1.63 μm (range 1.6 to 8.1 μm) (P<.05). It was 5.77 ± 3.39 μm (range 1.3 to 17.8 μm) in Group B and 1.59 ± 0.79 μm (range 0.6 to 5.6 μm) in Group C. CONCLUSION: Anterior segment OCT indicated a thinner and more homogeneous remodeled epithelium in the keratoconic eyes treated using the Athens protocol. FINANCIAL DISCLOSURE: Dr. Kanellopoulos is a consultant to Alcon Surgical, Inc.; Wavelight Laser Technologie AG; Avedro, Inc.; and i-Optics Optikgeräte GmbH. Dr. Asimellis has no financial or proprietary interest in any material or method mentioned. |
359 | What is the role of AMPK kinase in myocardial remodeling after myocardial infarction | AMP-activated protein kinase (AMPK) is a key sensor of cellular energy. The activation of AMPK by metformin prevents cardiac remodeling after myocardial infarction (MI).
Adiponectin protects the heart from ischemia-reperfusion injury through an AMPK-dependent mechanism.
AMPK activation by metformin and the subsequent suppression of TLRs activity could be considered as a target in protecting the infarcted heart. | [23122726, 22043210, 21572014, 22344560, 16155579] | 466 | AMP-activated protein kinase (AMPK) is a key sensor of cellular energy. The activation of AMPK by metformin prevents cardiac remodeling after myocardial infarction (MI). Besides, the innate immune response through TLRs is activated during MI. In the present study, the effects of short-term treatment with metformin on TLRs activity and its relation with AMPK in isoproterenol-induced MI were assessed in rats. To induce MI, a subcutaneous injection of isoproterenol was given to Wistar rats for two consecutive days. Metformin (25, 50, and 100mg/kg) was orally administered to rats twice daily for two days. Interstitial fibrosis was dose-dependently attenuated in the treated groups in comparison to the MI group (score: 1.25 ± 0.28 with 100 mg/kg metformin versus 3.5 ± 0.28; P<0.001). Further, metformin reduced TLR-dependent inflammatory cytokines as indexed by reduced myocardial levels of TNFα (maximum 68%; P<0.001) and IL6 (maximum 84%; P<0.001) as well as by reduced myocardial MPO activity (25%; P<0.01). It was found that the level of phosphorylated AMPK was significantly upregulated by 165% (P<0.001) when treated with 100 mg/kg of metformin, but not with 25 and 50mg/kg. This was associated with a remarkable suppression of TLR4 expression and reduction of protein level of TLRs adapter protein, MyD88 (P<0.01) in the infarcted myocardium. These results suggest that AMPK activation by metformin and the subsequent suppression of TLRs activity could be considered as a target in protecting the infarcted heart, which may indicate a link between AMPK and TLRs. Adenosine monophosphate - activated kinase (AMPK) plays a key role in the coordination of the heart's anabolic and catabolic pathways. It induces a cellular cascade at the center of maintaining energy homeostasis in the cardiomyocytes.. The activated AMPK is a heterotrimeric protein, separated into a catalytic α - subunit (63kDa), a regulating β - subunit (38kDa) and a γ - subunit (38kDa), which is allosterically adjusted by adenosine triphosphate (ATP) and adenosine monophosphate (AMP). The actual binding of AMP to the γ - subunit is the step which activates AMPK. AMPK serves also as a protein kinase in several metabolic pathways of the heart, including cellular energy sensoring or cardiovascular protection. The AMPK cascade represents a sensitive system, activated by cellular stresses that deplete ATP and acts as an indicator of intracellular ATP/AMP. In the context of cellular stressors (i.e. hypoxia, pressure overload, hypertrophy or ATP deficiency) the increasing levels of AMP promote allosteric activation and phosphorylation of AMPK. As the concentration of AMP begins to increase, ATP competitively inhibits further phosphorylation of AMPK. The increase of AMP may also be induced either from an iatrogenic emboli, percutaneous coronary intervention, or from atherosclerotic plaque rupture leading to an ischemia in the microcirculation. To modulate energy metabolism by phosphorylation and dephosphorylation is vital in terms of ATP usage, maintaining transmembrane transporters and preserving membrane potential. In this article, we review AMPK and its role as an important regulatory enzyme during periods of myocardial stress, regulating energy metabolism, protein synthesis and cardiovascular protection. Metformin is the first choice drug for the treatment of patients with diabetes, but its use is debated in patients with advanced cardiorenal disease. Epidemiological data suggest that metformin may reduce cardiac events, in patients both with and without heart failure. Experimental evidence suggests that metformin reduces cardiac ischemia-reperfusion injury. It is unknown whether metformin improves cardiac function (remodeling) in a long-term post-MI remodeling model. We therefore studied male, nondiabetic, Sprague-Dawley rats that were subjected to either myocardial infarction (MI) or sham operation. Animals were randomly allocated to treatment with normal water or metformin-containing water (250 mg·kg(-1)·day(-1)). At baseline, 6 wk, and 12 wk, metabolic parameters were analyzed and oral glucose tolerance tests (OGTT) were performed. Echocardiography and hemodynamic parameters were assessed 12 wk after MI. In the MI model, infarct size was significantly smaller after 12-wk metformin treatment (29.6 ± 3.2 vs. 38.0 ± 2.2%, P < 0.05). Moreover, metformin resulted in less left ventricular dilatation (6.0 ± 0.4 vs. 7.6 ± 0.6 mm, P < 0.05) and preservation of left ventricular ejection fraction (65.8 ± 3.7% vs. 48.6 ± 5.6%, P < 0.05) compared with MI control. The improved cardiac function was associated with decreased atrial natriuretic peptide mRNA levels in the metformin-treated group (50% reduction compared with MI, P < 0.05). Insulin resistance did not occur during cardiac remodeling (as indicated by normal OGTT) and fasting glucose levels and the pattern of the OGTT were not affected by metformin. Molecular analyses suggested that altered AMP kinase phosphorylation status and low insulin levels mediate the salutary effects of metformin. Altogether our results indicate that metformin may have potential to attenuate heart failure development after myocardial infarction, in the absence of diabetes and independent of systemic glucose levels. Insulin resistance is a recently identified mechanism involved in the pathophysiology of chronic heart failure (CHF). We investigated the effects of two insulin-sensitizing drugs (metformin and rosiglitazone) in a genetic model of spontaneously hypertensive, insulin-resistant rats (SHHF). Thirty SHHF rats were randomized into three treatment groups as follows: 1) metformin (100 mg/kg per day), 2) rosiglitazone (2 mg/kg per day), and 3) no drug. Ten Sprague-Dawley rats served as normal controls. At the end of the treatment period (12 months), the cardiac phenotype was characterized by histology, echocardiography, and isolated perfused heart studies. Metformin attenuated left ventricular (LV) remodeling, as shown by reduced LV volumes, wall stress, perivascular fibrosis, and cardiac lipid accumulation. Metformin improved both systolic and diastolic indices as well as myocardial mechanical efficiency, as shown by improved ability to convert metabolic energy into mechanical work. Metformin induced a marked activation of AMP-activated protein kinase, endothelial nitric oxide synthase, and vascular endothelial growth factor and reduced tumor necrosis factor-α expression and myocyte apoptosis. Rosiglitazone did not affect LV remodeling, increased perivascular fibrosis, and promoted further cardiac lipid accumulation. In conclusion, long-term treatment with metformin, but not with rosiglitazone, prevents the development of severe CHF in the SHHF model by a wide-spectrum interaction that involves molecular, structural, functional, and metabolic-energetic mechanisms. Obesity-related disorders are associated with the development of ischemic heart disease. Adiponectin is a circulating adipose-derived cytokine that is downregulated in obese individuals and after myocardial infarction. Here, we examine the role of adiponectin in myocardial remodeling in response to acute injury. Ischemia-reperfusion in adiponectin-deficient (APN-KO) mice resulted in increased myocardial infarct size, myocardial apoptosis and tumor necrosis factor (TNF)-alpha expression compared with wild-type mice. Administration of adiponectin diminished infarct size, apoptosis and TNF-alpha production in both APN-KO and wild-type mice. In cultured cardiac cells, adiponectin inhibited apoptosis and TNF-alpha production. Dominant negative AMP-activated protein kinase (AMPK) reversed the inhibitory effects of adiponectin on apoptosis but had no effect on the suppressive effect of adiponectin on TNF-alpha production. Adiponectin induced cyclooxygenase (COX)-2-dependent synthesis of prostaglandin E(2) in cardiac cells, and COX-2 inhibition reversed the inhibitory effects of adiponectin on TNF-alpha production and infarct size. These data suggest that adiponectin protects the heart from ischemia-reperfusion injury through both AMPK- and COX-2-dependent mechanisms. |
360 | What is the mechanism of action of solanezumab? | Solanezumab is a monoclonal anti-amyloid beta peptide (Aβ) antibody. It has been tested for treatment of Alzheimer's disease patients. | [22672770, 21504387, 22339463, 22110351, 22506132, 24119446, 21868184, 22482074, 22292124, 23254906, 21784350, 22848160, 23574434, 21614635, 24063020, 24101429, 23663286, 23416764, 22288451, 24259408, 24399967, 23568994, 20375655, 23847530, 23582316, 22134132, 21897718, 23735288, 21694458, 24353405] | 467 | INTRODUCTION: Alzheimer's disease (AD) is a debilitating neurodegenerative illness affecting over 35 million people worldwide. Solanezumab is a monoclonal antibody that binds to β-amyloid (Aβ), a protein that plays a key role in the pathogenesis of AD. The drug is currently being investigated in Phase III trials as a disease-modifying treatment for AD. AREAS COVERED: This paper reviews literature on solanezumab that is available in PubMed from 2008 to 2010, other treatment trials in clinicaltrials.gov and published abstracts from conferences. The article also provides a discussion of the early trials of AN1792 and an overview of the immunotherapies currently in development. The authors provide the reader with a critical appraisal of the to-date clinical trial data on solanezumab and its implications for the broader field of immunotherapies for AD. EXPERT OPINION: Solanezumab can neutralize soluble Aβ peptides, which may represent the more neurotoxic of the Aβ species. Phase II findings support the compound's safety, which has been a concern for some Aβ immunotherapies. Cerebrospinal and plasma biomarker changes with solanezumab treatment are encouraging. Results of the ongoing Phase III trials will be instrumental in determining the drug's clinical significance. The exact mechanisms leading to Alzheimer's disease (AD) are largely unknown, limiting the identification of effective disease-modifying therapies. The two principal neuropathological hallmarks of AD are extracellular β-amyloid (Aβ), peptide deposition (senile plaques) and intracellular neurofibrillary tangles containing hyperphosphorylated tau protein. During the last decade, most of the efforts of the pharmaceutical industry were directed against the production and accumulation of Aβ. The most innovative of the pharmacological approaches was the stimulation of Aβ clearance from the brain of AD patients via the administration of Aβ antigens (active vaccination) or anti-Aβ antibodies (passive vaccination). Several active and passive anti-Aβ vaccines are under clinical investigation. Unfortunately, the first active vaccine (AN1792, consisting of preaggregate Aβ and an immune adjuvant, QS-21) was abandoned because it caused meningoencephalitis in approximately 6% of treated patients. Anti-Aβ monoclonal antibodies (bapineuzumab and solanezumab) are now being developed. The clinical results of the initial studies with bapineuzumab were equivocal in terms of cognitive benefit. The occurrence of vasogenic edema after bapineuzumab, and more rarely brain microhemorrhages (especially in Apo E ε4 carriers), has raised concerns on the safety of these antibodies directed against the N-terminus of the Aβ peptide. Solanezumab, a humanized anti-Aβ monoclonal antibody directed against the midregion of the Aβ peptide, was shown to neutralize soluble Aβ species. Phase II studies showed a good safety profile of solanezumab, while studies on cerebrospinal and plasma biomarkers documented good signals of pharmacodynamic activity. Although some studies suggested that active immunization may be effective against tau in animal models of AD, very few studies regarding passive immunization against tau protein are currently available. The results of the large, ongoing Phase III trials with bapineuzumab and solanezumab will tell us if monoclonal anti-Aβ antibodies may slow down the rate of deterioration of AD. Based on the new diagnostic criteria of AD and on recent major failures of anti-Aβ drugs in mild-to-moderate AD patients, one could argue that clinical trials on potential disease-modifying drugs, including immunological approaches, should be performed in the early stages of AD. Alzheimer's disease, the most common cause of dementia, is characterized by two major pathological hallmarks: amyloid plaques and neurofibrillary tangles. Based on these two indicators, an amyloid cascade hypothesis was proposed, and accordingly, most current therapeutic approaches are now focused on the removal of β-amyloid peptides (Aβ from the brain. Additionally, strategies for blocking tau hyperphosphorylation and aggregation have been suggested, including the development of drugs that can block the formation of tangles. However, there are no true disease-modifying drugs in the current market, though many drugs based on theories other than Aβ and tau pathology are under development. The purpose of this review was to provide information on the current development of AD drugs and to discuss the issues related to drug development. Increasing evidence suggests that inflammatory and immune components in brain are important in Alzheimer's disease (AD) and anti-inflammatory and immunotherapeutic approaches may be amenable to AD treatment. It is known that complement activation occurs in the brain of patients with AD, and contributes to a local inflammatory state development which is correlated with cognitive impairment. In addition to the complement's critical role in the innate immune system recognizing and killing, or targeting for destruction, complement proteins can also interact with cell surface receptors to promote a local inflammatory response and contributes to the protection and healing of the host. On the other hand, complement activation also causes inflammation and cell damage as an essential immune function to eliminate cell debris and potentially toxic protein aggregates. It is the balance of these seemingly competing events that influences the ultimate state of neuronal function. Our mini review will be focusing on the unique molecular interactions happening in the AD development, the functional outcomes of those interactions, as well as the contribution of each element to AD. Alzheimer's disease (AD) is defined by the concurrence of accumulation of abnormal aggregates composed of two proteins: Amyloid beta (Aβ) and tau, and of cellular changes including neurite degeneration and loss of neurons and cognitive functions. Based on their strong association with disease, genetically and pathologically, it is not surprising that there has been a focus towards developing therapies against the aggregated structures. Unfortunately, current therapies have but mild benefit. With this in mind we will focus on the relationship of synaptic plasticity with Aβ and tau protein and their role as potential targets for the development of therapeutic drugs. Finally, we will provide perspectives in developing a multifactorial strategy for AD treatment. As the societal and economic burdens of Alzheimer's disease (AD) continue to mount, so does the need for therapies that slow the progression of the illness. Beta amyloid has long been recognized as the pathologic hallmark of AD, and the past decade has seen significant progress in the development of various immunotherapeutic approaches targeting beta amyloid. This paper reviews active and passive approaches aimed at beta amyloid, with a focus on clinical trial data. The start of the new year signals that it is time for mAbs' annual review of the therapeutic monoclonal antibodies (mAbs) in active Phase 2/3 or Phase 3 clinical studies. The entire clinical pipeline currently includes ~350 mAbs, but most of these are in early development. As of the beginning of 2013, our "Antibodies to watch" list includes 28 single mAbs and one mAb mixture that are undergoing evaluation in Phase 3 studies for inflammatory or immunological disorders, cancers, high cholesterol, osteoporosis, Alzheimer disease and infectious disease. In alphabetical order, the 28 mabs are alirocumab, AMG 145, elotuzumab, epratuzumab, farletuzumab, gantenerumab, gevokizumab, inotuzumab ozogamicin, itolizumab, ixekizumab, lebrikizumab, mepolizumab, naptumomab estafenatox, necitumumab, nivolumab, obinutuzumab, ocrelizumab, onartuzumab, racotumomab, ramucirumab, reslizumab, romosozumab, sarilumab, secukinumab, sirukumab, solanezumab, tabalumab, and vedolizumab. The mixture of actoxumab and bezlotoxumab is being evaluated in two Phase 3 studies as a treatment for Clostridium difficile infection. BACKGROUND: Cerebral vasogenic edema (VE) has been reported to occur during antiamyloid immunotherapy. VE may be associated with central nervous system pathology with blood-brain barrier disruptions; however, less is known about the prevalence of naturally occurring VE in patients with Alzheimer's disease (AD). METHODS: Fluid-attenuated inversion recovery imaging sequences were obtained from four ongoing multicenter, randomized, double-blind, placebo-controlled, phase 3 trials in patients with mild-to-moderate AD. The first set of baseline scans was from patients in volumetric magnetic resonance imaging addenda in the Interrupting Alzheimer's Dementia by EvaluatiNg Treatment of Amyloid PaThologY (IDENTITY) studies examining semagacestat, a γ-secretase inhibitor (cohort 1, n = 621). The second set of baseline scans was from the EXPanding alzhEimer's Disease InvestigaTIONs (EXPEDITION) studies examining solanezumab, an anti-Aβ monoclonal antibody (cohort 2, n = 2141). Readers were blinded to patient-identifying information and future treatment. A third set of baseline scans was from the first 700 patients who underwent protocol-specified magnetic resonance imaging before randomization in the EXPEDITION studies (cohort 3). The analysis used three neuroradiologists: two performed independent primary interpretations and the third was the adjudicator. Readers were blinded to patient information, treatment, protocol, and time point. RESULTS: Four cases of asymptomatic VE were detected at baseline/screening. Two VE cases were due to underlying extra-axial mass lesions. The third VE case was associated with numerous microhemorrhages in keeping with cerebral amyloid angiopathy-related inflammation or Aβ-related angiitis. The final VE case demonstrated localized sulcal fluid-attenuated inversion recovery imaging hyperintensity. No VE was detected in cohort 3 by readers blinded to patient baseline status. CONCLUSIONS: VE seems to be rare at baseline in patients with AD in clinical trials, 2 of 2,762 associated with AD. Additional cohorts should be evaluated to support these findings. We are now in an aging population, so neurological disorders, particularly the neurodegenerative diseases, are becoming more prevalent in society. As per the epidemiological studies, Europe alone suffers 35% of the burden, indicating an alarming rate of disease progression. Further, treatment for these disorders is a challenging area due to the presence of the tightly regulated blood-brain barrier and its unique ability to protect the brain from xenobiotics. Conventional therapeutics, although effective, remain critically below levels of optimum therapeutic efficacy. Hence, methods to overcome the blood-brain barrier are currently a focus of research. Nanotechnological applications are gaining paramount importance in addressing this question, and yielding some promising results. This review addresses the pathophysiology of the more common neurological disorders and novel drug candidates, along with targeted nanoparticle applications for brain delivery. Several lines of evidence indicate that amyloid β (Aβ), particularly Aβ oligomers (AβOs), plays a causative role in Alzheimer's disease. However, the mechanisms underlying the action of an anti-AβO antibody to clarify the toxic action of AβOs remain elusive. Here, we showed that the anti-AβO antibody (monoclonal 72D9) can modify the Aβ aggregation pathway. We also found that 72D9 directly sequesters both extracellular and intraneuronal AβOs in a nontoxic state. Thus, therapeutic intervention targeting AβOs is a promising strategy for neuronal protection in Alzheimer's disease. Alzheimer's disease (AD) is the most common dementia in the industrialized world, with prevalence rates well over 30% in the over 80-years-old population. The dementia causes enormous costs to the social healthcare systems, as well as personal tragedies for the patients, families and caregivers. AD is strongly associated with Amyloid-beta (Aβ) protein aggregation, which results in extracellular plaques in the brain, and according to the amyloid cascade hypothesis appeared to be a promising target for the development of AD therapeutics. Within the past decade convincing data has arisen positioning the soluble prefibrillar Aβ-aggregates as the prime toxic agents in AD. However, different Aβ aggregate species are described but their remarkable metastability hampers the identification of a target species for immunization. Passive immunotherapy with monoclonal antibodies (mAbs) against Aβ is in late clinical development but recently the two most advanced mAbs, Bapineuzumab and Solanezumab, targeting an N-terminal or central epitope, respectively, failed to meet their target of improving or stabilizing cognition and function. Preliminary data from off-label treatment of a small cohort for 3 years with intravenous polyclonal immunoglobulins (IVIG) that appear to target different conformational epitopes indicate a cognitive stabilization. Thus, it might be the more promising strategy reducing the whole spectrum of Aβ-aggregates than to focus on a single aggregate species for immunization. Bapineuzumab is a humanized antibody developed by Pfizer and Johnson & Johnson targeting the amyloid (Aβ) plaques that underlie Alzheimer's disease neuropathology. Here we report the crystal structure of a Fab-Aβ peptide complex that reveals Bapineuzumab surprisingly captures Aβ in a monomeric helical conformation at the N-terminus. Microscale thermophoresis suggests that the Fab binds soluble Aβ(1-40) with a K(D) of 89 (±9) nM. The structure explains the antibody's exquisite selectivity for particular Aβ species and why it cannot recognize N-terminally modified or truncated Aβ peptides. Solanezumab (LY2062430) is a humanized monoclonal antibody that binds to the central region of β-amyloid, a peptide believed to play a key role in the pathogenesis of Alzheimer's disease (AD). Eli Lilly & Co is developing an intravenous formulation of solanezumab for the treatment of mild-to-moderate AD. Acute and subchronic treatment with solanezumab of transgenic mice attenuated or reversed memory deficits with no effects on incidence or severity of cerebral amyloid angiopathy-associated microhemorrhages, a severe side effect associated with bapineuzumab, another monoclonal antibody. Phase II studies in AD patients have shown a good safety profile with encouraging indications on cerebrospinal and plasma biomarkers. The drug is currently being investigated in Phase III trials. While there is a strong hope that solanezumab may represent the first effective passive vaccine for AD treatment, skepticism still exists on the ability of the drug to slow the rate of deterioration in patients with fully established disease. Alzheimer's disease is characterized by the accumulation of amyloid deposits in the brain and the progressive loss of cognitive functions. Although the precise role of amyloid-β in disease progression remains somewhat controversial, many efforts to halt or reverse disease progression have focussed on reducing its synthesis or enhancing its removal. It is believed that brain and peripheral soluble amyloid-β are in equilibrium and it has previously been hypothesized that a reduction in peripheral amyloid-β can lower brain amyloid-β, thereby reducing formation of plaques predominantly composed of insoluble amyloid-β; the so-called peripheral sink hypothesis. Here we describe the use of an amyloid-β degrading enzyme, the endogenous metallopeptidase neprilysin, which is fused to albumin to extend plasma half-life and has been engineered to confer increased amyloid-β degradation activity. We used this molecule to investigate the effect of degradation of peripheral amyloid-β on amyloid-β levels in the brain and cerebrospinal fluid after repeated intravenous dosing for up to 4 months in Tg2576 transgenic mice, and 1 month in rats and monkeys. This molecule proved highly effective at degradation of amyloid-β in the periphery but did not alter brain or cerebrospinal fluid amyloid-β levels, suggesting that the peripheral sink hypothesis is not valid and is the first time that this has been demonstrated in non-human primates. Amyloid β (Aβ) accumulation is considered the main culprit in the pathogenesis of Alzheimer's disease (AD). Recent studies suggest that decreasing Aβ production at very early stages of AD could be a promising strategy to slow down disease progression. Serotonin 5-HT4 receptor activation stimulates α-cleavage of the amyloid precursor protein (APP), leading to the release of the soluble and neurotrophic sAPPα fragment and thus precluding Aβ formation. Using the 5XFAD mouse model of AD that shows accelerated Aβ deposition, we investigated the effect of chronic treatments (treatment onset at different ages and different durations) with the 5-HT4 receptor agonist RS 67333 during the asymptomatic phase of the disease. Chronic administration of RS 67333 decreased concomitantly the number of amyloid plaques and the level of Aβ species. Reduction of Aβ levels was accompanied by a striking decrease in hippocampal astrogliosis and microgliosis. RS 67333 also transiently increased sAPPα concentration in the cerebrospinal fluid and brain. Moreover, a specific 5-HT4 receptor antagonist (RS 39604) prevented the RS 67333-mediated reduction of the amyloid pathology. Finally, the novel object recognition test deficits of 5XFAD mice were reversed by chronic treatment with RS 67333. Collectively, these results strongly highlight this 5-HT4 receptor agonist as a promising disease modifying-agent for AD. OBJECTIVES: Active and passive immunization strategies have been suggested as possible options for the treatment of Alzheimer disease (AD). LY2062430 (solanezumab) is a humanized monoclonal antibody being studied as a putative disease-modifying treatment of AD. METHODS: Patients with mild to moderate AD were screened and selected for inclusion. Initial screening was performed for 54 subjects, and 29 of these underwent additional screening; after this second screening, a total of 19 subjects were included. Single doses of solanezumab using 0.5, 1.5, 4.0, and 10.0 mg/kg were administered. Safety assessments included gadolinium-enhanced magnetic resonance imaging of the brain and cerebrospinal fluid (CSF) analyses at baseline and 21 days after dosing. Plasma and CSF concentrations of solanezumab and amyloid beta (Abeta) and cognitive evaluations were obtained. RESULTS: Administration of solanezumab was generally well tolerated except that mild self-limited symptoms consistent with infusion reactions occurred for 2 of 4 subjects given 10 mg/kg. No evidence of meningoencephalitis, microhemorrhage, or vasogenic edema was present based on magnetic resonance image and CSF analyses. A substantial dose-dependent increase in total (bound plus unbound) Abeta was demonstrated in plasma; CSF total Abeta also increased. No changes in cognitive scores occurred. CONCLUSIONS: A single dose of solanezumab was generally well tolerated, although infusion reactions similar to those seen with administration of other proteins may occur with higher doses. A dose-dependent change in plasma and CSF Abeta was observed, although changes in cognitive scores were not noted. Further studies of solanezumab for the treatment of AD are warranted. Author information: (1)Department of Internal Medicine, Medwin Hospital, Nampally, Hyderabad, Andhra Pradesh, India. Intravenous immunoglobulin (IVIG) products are prepared from purified plasma immunoglobulins from large numbers of healthy donors. Pilot studies with the IVIG preparations Octagam and Gammagard in individuals with mild-to-moderate Alzheimer's disease (AD) suggested stabilization of cognitive functioning in these patients, and a phase II trial with Gammagard reported similar findings. However, subsequent reports from Octagam's phase II trial and Gammagard's phase III trial found no evidence for slowing of AD progression. Although these recent disappointing results have reduced enthusiasm for IVIG as a possible treatment for AD, it is premature to draw final conclusions; a phase III AD trial with the IVIG product Flebogamma is still in progress. IVIG was the first attempt to use multiple antibodies to treat AD. This approach should be preferable to administration of single monoclonal antibodies in view of the multiple processes that are thought to contribute to AD neuropathology. Development of "AD-specific" preparations with higher concentrations of selected human antibodies and perhaps modified in other ways (such as increasing their anti-inflammatory effects and/or ability to cross the blood-brain barrier) should be considered. Such preparations, if generated with recombinant technology, could overcome the problems of high cost and limited supplies, which have been major concerns relating to the possible widespread use of IVIG in AD patients. This review summarizes the recent AD IVIG trials and discusses the major issues relating to possible use of IVIG for treating AD, as well as the critical questions which remain. Tau measurements in cerebrospinal fluid (CSF) are gaining acceptance as aids to diagnosis of Alzheimer's disease (AD) and differentiation from other dementias. Two ELISA assays, the INNOTEST® hTAU Ag and the INNOTEST® PHOSPHO-TAU(181P) for quantification of t-tau and p-tau181 respectively, have been validated to regulatory standards. Validation parameters were determined by repeated testing of human CSF pools. Specimens from Phase 2 studies of the γ-secretase inhibitor semagacestat and the therapeutic antibody solanezumab at baseline and following 12-14 weeks of treatment were also tested. Estimated intra-assay CV for repeated testing of 3 CSF pools were ≤11.5% and RE varied between -14.1% and +6.4%. Inter-assay CV for t-tau was <5% and RE was within ±8%. For p-tau181, inter-assay CV was <9% and RE was within ±2.5%. Total CV (intra-assay plus inter-assay) were below 10% for both analytes. Up to 20-fold dilutional linearity was demonstrated for both analytes. Stability of t-tau and p-tau181 was demonstrated in CSF during five freeze-thaw cycles at ≤-20 °C and ≤-70 °C and at 18-22 °C for up to 24 h. Neither semagacestat nor solanezumab interfered with either assay. Inter-individual t-tau and p-tau181 concentrations were highly variable but intra-individual variations were small. These assays are suitable for analysis of CSF t-tau and p-tau181 in a single laboratory supporting multi-center AD clinical trials. No effect of treatment with semagacestat or solanezumab was observed in response to three months of drug administration. |
361 | What are the major clinical Villefranche criteria for classic Ehlers-Danlos syndrome? | The major clinical Villefranche criteria for classic Ehlers-Danlos syndrome are skin hyperextensibility, dystrophic scarring, and joint hypermobility. | [22696272] | 468 | Type V collagen mutations are associated with classic Ehlers-Danlos Syndrome (EDS), but it is unknown for which proportion they account and to what extent other genes are involved. We analyzed COL5A1 and COL5A2 in 126 patients with a diagnosis or suspicion of classic EDS. In 93 patients, a type V collagen defect was found, of which 73 were COL5A1 mutations, 13 were COL5A2 mutations and seven were COL5A1 null-alleles with mutation unknown. The majority of the 73 COL5A1 mutations generated a COL5A1 null-allele, whereas one-third were structural mutations, scattered throughout COL5A1. All COL5A2 mutations were structural mutations. Reduced availability of type V collagen appeared to be the major disease-causing mechanism, besides other intra- and extracellular contributing factors. All type V collagen defects were identified within a group of 102 patients fulfilling all major clinical Villefranche criteria, that is, skin hyperextensibility, dystrophic scarring and joint hypermobility. No COL5A1/COL5A2 mutation was detected in 24 patients who displayed skin and joint hyperextensibility but lacked dystrophic scarring. Overall, over 90% of patients fulfilling all major Villefranche criteria for classic EDS were shown to harbor a type V collagen defect, which indicates that this is the major--if not only--cause of classic EDS. |
362 | What is the treatment of neuropathic pain in children? | It is unclear if any treatment is registered for pediatric use. The reported treatments are:
Oxcarbazepine
Opioids alone, in rotations or with Analgesics (e.g. Ketamine and Lidocaine infusion)
Opioids and Benzodiazepines
Pregabalin - is one of the first drugs registered for the treatment of neuropathic pain. It is unclear if Pregabalin is registered for the treatment of neuropathic pain in children specifically but it is being used in practice.
Tricyclic Antidepressants
Lidocaine 5% patches for chronic localized neuropathic pain | [22401313, 11902308, 15265351, 18363625, 7561230, 22735246, 12712053, 21332246, 18820538, 22147611] | 469 | The purpose of this retrospective study was to determine the therapeutic value of opioid rotation in a large pediatric oncology center. The details for opioid prescriptions, over the course of a year, were obtained from the medical records of children with cancer who had a rotation of opioid during their admission. Twenty-two children or 14% of children on opioid therapy underwent 30 opioid rotations. Mucositis was the cause of pain in 19 (70%) children, bone pain in 3 (11%) children, and postoperative, visceral, or neuropathic pain in the remainder. The opioid was rotated either for excessive side effects with adequate analgesia (70%), excessive side effects with inadequate analgesia (16.7%), or tolerance (6.7%). Five (23%) children required two rotations, 3 during the same admission. The favored rotations were morphine to fentanyl in 20 (67%) children and fentanyl to hydromorphone in 6 (20%). Adverse opioid effects were resolved in 90% of cases, all failures occurred when morphine was rotated to fentanyl. There was no significant loss of pain control or increase in mean morphine equivalent dose requirements. Opioid rotation had a positive impact on managing dose-limiting side effects of, or tolerance to, opioid therapy during cancer pain treatment in children. This was accomplished without loss of pain control or having to significantly increase the dose of opioid therapy. We describe a case series of five adolescents who were managed with lidocaine 5% patches for chronic localized neuropathic pain from a variety of causes with minimal adverse effects. Treatment was effective in four of five patients with only one patient complaining of minimal pain relief. 5% Lidocaine patches have been used for treatment of chronic neuropathic pain in adults and we have found this to be effective in management of localized neuropathic pain in children and adolescents. Oral amitriptyline has been used as an analgesic in a wide range of pain settings. Despite long-term availability of a parenteral form, the few reports about this formulation have been limited to pharmacokinetic studies in normal volunteers, trials in depressed patients, and analyses of electroencephalogram (EEG) activation. We retrospectively reviewed our experience using intravenous (IV) amitriptyline at Children's Hospital, Boston and at Children's Hospital at Stanford. Eight children (aged 5-16.6 years), who were unable to tolerate medications by the oral route, received IV amitriptyline for a variety of indications, including neuropathic pain, depression, sleep disturbance, and as an adjuvant agent for opioid analgesia. One patient experienced an extrapyramidal reaction temporally related to the administration of IV amitriptyline, which was successfully managed with diphenhydramine. Further prospective, controlled studies are needed to further assess the safety, efficacy and tolerability of this novel use of amitriptyline. Oxcarbazepine, a metabolite of carbamazepine, is used as an antiepileptic, analgesic for neuropathic pain and in the treatment of affective disorders. It has been approved by the Food and Drug Administration for partial seizures in adults as both adjunctive and monotherapy, and as adjunctive therapy in children aged from 2 to 16 years (http://www.fda.gov/ohrms/dockets/ac/06/briefing/2006-4254b_07_05_KP%20OxcarbazepineFDAlabel102005.pdf). We present a case of serotonin syndrome, which was precipitated by this medicine in a patient who had been predisposed by long-term treatment with sertraline, a selective serotonin reuptake inhibitor. This is the first reported fatality due to this drug interaction and only the second case of serotonin syndrome reported with oxcarbazepine. Physicians should consider this risk when prescribing the above combination. OBJECTIVE: Although vulvodynia occurs in approximately 7% of adult American women, we hypothesize that vulvodynia also occurs in young girls and that they respond to treatments that are similar to those used in women with this disorder. MATERIALS AND METHODS: This is a retrospective case study of vulvodynia in preadolescent girls seen in our referral practice. Records of all office visits and any telephone or e-mailed follow-up were reviewed. RESULTS: Between October 1996 and April 2006, 6 girls ages 4 to 11 years were evaluated and diagnosed with vulvodynia. Pain had been present for several months to 7 years, and most patients had been seen by several physicians before having this diagnosis made. Treatment was typically initiated with a tricyclic antidepressant, and 5 of the 6 girls noted improvement in their symptoms, including 2 who had marked improvement, and another 3 with substantial improvement who were able to discontinue therapy without a recurrence. CONCLUSIONS: Vulvodynia does occur among young girls and, when treated as a neuropathic pain disorder, was found to dramatically improve or remit in the majority of those treated in this small case series. This underrecognized disorder should be considered in cases of ongoing vulvar discomfort, regardless of age. |
363 | Which phenomenon is known as the "calcium paradox" in the isolated perfused heart? | When hearts are reperfused with Ca++ after a short period of Ca++-free perfusion, irreversible loss of electrical and mechanical activity is observed. This phenomenon, first described by Zimmerman and Hulsmann, was termed the "calcium paradox". This phenomenon is concomitant with a rapid consumption of myocardial high-energy phosphate stores. The Ca(2+) paradox represents a good model to study Ca(2+) overload injury in ischemic heart diseases. The Ca(2+) paradox can be elicited by perfusing isolated hearts with Ca(2+)-free media for 3 min or 5 min followed by 30 min of Ca(2+) repletion. A possible mechanism for the 'calcium paradox' is that exposure to a calcium-free medium removes extracellular calcium rendering the sarcolemma more permeable to calcium. On calcium repletion, cell injury is triggered by calcium influx. Cardiac dysfunction due to Ca2+ -paradox may be associated with apoptosis. | [6823106, 6626051, 16901476, 23284963, 3117031, 4058248, 1031954, 2720439, 24289081] | 470 | Isolated perfusion of the heart with a Ca2+-free perfusate followed by a Ca2+-containing perfusate causes dramatic alterations in the physiology and biochemistry of the tissue, a phenomenon known as the calcium paradox. A similar paradoxical effect of Ca2+ has also been reported to occur in the kidney. In this study an attempt was made to reproduce the calcium paradox in canine kidneys and to characterize more fully its metabolic consequences. Canine kidneys were perfused with Krebs-Henseliet bicarbonate buffer free of Ca2+ for 30 min followed by perfusion with Ca2+ (1.5 mM). Unlike previously reported results no sudden decrease in flow was there a Ca2+-related sharp rise in rate of release of lactic dehydrogenase. In addition, we found no significant change in the level of tissue adenine nucleotides or functionality of isolated mitochondria. It is concluded that there is no calcium paradox in canine kidney under these conditions and it is suggested that the Ca2+ paradox may be characteristics only of muscle tissue that can undergo Ca2+-dependent contraction. Injury is sustained by isolated hearts on repletion with calcium after a short period of perfusion with calcium-free medium at 37 degrees. A possible mechanism for the 'calcium paradox' is that exposure to a calcium-fre medium removes extracellular calcium rendering the sarcolemma more permeable to calcium. On calcium repletion, cell injury is triggered by calcium influx. Since lanthanum is known to displace calcium from extracellular pools in heart, it was used in an attempt to modulate the injury of the calcium paradox. The presence of 10 microM lanthanum in the calcium-free perfusion fluid was found to inhibit totally protein release normally produced by subsequent calcium exposure. When lanthanum was added after the calcium-free period and before calcium repletion, protein release was only partly prevented. This shows that a change in membrane properties occurred during the calcium-free perfusion period which could be prevented, but not reversed, by the addition of lanthanum. The Ca(2+) paradox represents a good model to study Ca(2+) overload injury in ischemic heart diseases. We and others have demonstrated that contracture and calpain are involved in the Ca(2+) paradox-induced injury. This study aimed to elucidate their roles in this model. The Ca(2+) paradox was elicited by perfusing isolated rat hearts with Ca(2+)-free KH media for 3 min or 5 min followed by 30 min of Ca(2+) repletion. The LVDP was measured to reflect contractile function, and the LVEDP was measured to indicate contracture. TTC staining and the quantification of LDH release were used to define cell death. Calpain activity and troponin I release were measured after Ca(2+) repletion. Ca(2+) repletion of the once 3-min Ca(2+) depleted hearts resulted in almost no viable tissues and the disappearance of contractile function. Compared to the effects of the calpain inhibitor MDL28170, KB-R7943, an inhibitor of the Na(+)/Ca(2+) exchanger, reduced the LVEDP level to a greater extent, which was well correlated with improved contractile function recovery and tissue survival. The depletion of Ca(2+) for 5 min had the same effects on injury as the 3-min Ca(2+) depletion, except that the LVEDP in the 5-min Ca(2+) depletion group was lower than the level in the 3-min Ca(2+) depletion group. KB-R7943 failed to reduce the level of LVEDP, with no improvement in the LVDP recovery in the hearts subjected to the 5-min Ca(2+) depletion treatment; however, KB-R7943 preserved its protective effects in surviving tissue. Both KB-R7943 and MDL28170 attenuated the Ca(2+) repletion-induced increase in calpain activity in 3 min or 5 min Ca(2+) depleted hearts. However, only KB-R7943 reduced the release of troponin I from the Ca(2+) paradoxic heart. These results provide evidence suggesting that contracture is the main cause for contractile dysfunction, while activation of calpain mediates cell death in the Ca(2+) paradox. "Calcium paradox" as a term describes the deleterious effects conferred to a heart perfused with a calcium-free solution followed by repletion, including loss of mechanical activity and sarcomere disruption. Given that the signaling mechanisms triggered by calcium paradox remain elusive, in the present study, we tried to investigate them in the isolated perfused heart from Rana ridibunda. Calcium paradox was found to markedly activate members of the MAPKs (p43-ERK, JNKs, p38-MAPK). In addition to lactate dehydrogenase (LDH) release in the perfusate (indicative of necrosis), we also confirmed the occurrence of apoptosis by using the TUNEL assay and identifying poly(ADP-ribose) polymerase (PARP) fragmentation and upregulated Bax expression. Furthermore, using MDL28170 (a selective calpain inhibitor), a role for this protease was revealed. In addition, various divalent cations were shown to exert a protective effect against the calcium paradox. Interestingly, SB203580, a p38-MAPK inhibitor, alleviated calcium-paradox-conferred apoptosis. This result indicates that p38-MAPK plays a pro-apoptotic role, contributing to the resulting myocardial dysfunction and cell death. To our knowledge, this is the first time that the calcium paradox has been shown to induce apoptosis in amphibians, with p38-MAPK and calpain playing significant roles. |
364 | Is there a crystal structure of the full-length of the flaviviridae NS5(Methyltransferase - RNA depended RNA Polymerase) ? | Yes, there is the crystal Structure of the full-length Japanese encephalitis virus (Flaviviridae) NS5 - PDB:4K6M | [17287213, 19710254, 22365326, 22757685, 23950717, 23355615] | 471 | The West Nile virus (WNV) NS5 protein contains a methyltransferase (MTase) domain involved in RNA capping and an RNA-dependent RNA polymerase (RdRp) domain essential for virus replication. Crystal structures of individual WNV MTase and RdRp domains have been solved; however, the structure of full-length NS5 has not been determined. To gain more insight into the structure of NS5 and interactions between the MTase and RdRp domains, we generated a panel of seven monoclonal antibodies (mAbs) to the NS5 protein of WNV (Kunjin strain) and mapped their binding sites using a series of truncated NS5 proteins and synthetic peptides. Binding sites of four mAbs (5D4, 4B6, 5C11 and 6A10) were mapped to residues 354-389 in the fingers subdomain of the RdRp. This is consistent with the ability of these mAbs to inhibit RdRp activity in vitro and suggests that this region represents a potential target for RdRp inhibitors. Using a series of synthetic peptides, we also identified a linear epitope (bound by mAb 5H1) that mapped to a 13 aa stretch surrounding residues 47 and 49 in the MTase domain, a region predicted to interact with the palm subdomain of the RdRp. The failure of one mAb (7G6) to bind both N- and C-terminally truncated NS5 recombinants indicates that the antibody recognizes a conformational epitope that requires the presence of residues in both the MTase and RdRp domains. These data support a structural model of the full-length NS5 molecule that predicts a physical interaction between the MTase and the RdRp domains. The West Nile virus (WNV) genome contains a single RNA-dependent RNA polymerase (RdRp) gene, which is responsible for replication of the viral genome and, as such, is an important target for antiviral therapy. Viral RdRps are known to lack proofreading capabilities and as a result viruses such as WNV exist as a mixture of viral genotypes within an infection, enabling the virus to readily emerge and adapt to new host environments. To test the consequences of subtle structural alterations remote from the RdRp active-site, the following single point mutations were engineered in the WNV NS5 RdRp coding region: T363N, A365N, and T537I; these mutations were selected in an effort to stabilize the secondary structural elements near the rNTP binding pocket of the RdRp. Mutant viruses were tested in vitro on Vero, C6/36, Culex tarsalis and DF-1 cell types and in vivo in one day old chickens and Culex pipiens mosquitoes. Plaque morphology was affected by each mutation and growth and RNA replication kinetics were altered as well. Our results demonstrate that subtle alteration of the RdRp protein away from the active site can have a significant overall biological effect on WNV fitness, and that this effect can be host-dependent. Dengue virus (DENV) nonstructural protein 5 (NS5) is composed of two globular domains separated by a 10-residue linker. The N-terminal domain participates in the synthesis of a mRNA cap 1 structure ((7Me)GpppA(2'OMe)) at the 5' end of the viral genome and possesses guanylyltransferase, guanine-N7-methyltransferase, and nucleoside-2'O-methyltransferase activities. The C-terminal domain is an RNA-dependent RNA polymerase responsible for viral RNA synthesis. Although crystal structures of the two isolated domains have been obtained, there are no structural data for full-length NS5. It is also unclear whether the two NS5 domains interact with each other to form a stable structure in which the relative orientation of the two domains is fixed. To investigate the structure and dynamics of DENV type 3 NS5 in solution, we conducted small-angle X-ray scattering experiments with the full-length protein. NS5 was found to be monomeric and well-folded under the conditions tested. The results of these experiments also suggest that NS5 adopts multiple conformations in solution, ranging from compact to more extended forms in which the two domains do not seem to interact with each other. We interpret the multiple conformations of NS5 observed in solution as resulting from weak interactions between the two NS5 domains and flexibility of the linker in the absence of other components of the replication complex. Monocyte chemoattractant protein 1-induced protein 1 (MCPIP1), belonging to the MCPIP family with highly conserved CCCH-type zinc finger and Nedd4-BP1, YacP Nuclease domains, has been implicated in negative regulation of the cellular inflammatory responses. In this report, we demonstrate for the first time that this RNA-binding nuclease also targets viral RNA and possesses potent antiviral activities. Overexpression of the human MCPIP1, but not MCPIP2, MCPIP3 or MCPIP4, inhibited Japanese encephalitis virus (JEV) and dengue virus (DEN) replication. The functional analysis of MCPIP1 revealed that the activities of RNase, RNA binding and oligomerization, but not deubiqutinase, are required for its antiviral potential. Furthermore, infection of other positive-sense RNA viruses, such as sindbis virus and encephalomyocarditis virus, and negative-sense RNA virus, such as influenza virus, as well as DNA virus, such as adenovirus, can also be blocked by MCPIP1. Moreover, the endogenous MCPIP1 gene expression was induced by JEV and DEN infection, and knockdown of MCPIP1 expression enhanced the replication of JEV and DEN in human cells. Thus, MCPIP1 can act as a host innate defense via RNase activity for targeting and degrading viral RNA. |
365 | How do Hsp70 and Hsp110 affect mRNA stability? | Hsp70 and Hsp110 act as RNA-binding entities in vivo to guide the appropriate folding of RNA substrates for subsequent regulatory processes such as mRNA degradation and/or translation. | [10358092] | 472 | In this study, in vitro RNA binding by members of the mammalian 70-kDa heat shock protein (Hsp) family was examined. We show that Hsp/Hsc70 and Hsp110 proteins preferentially bound AU-rich RNA in vitro. Inhibition of RNA binding by ATP suggested the involvement of the N-terminal ATP-binding domain. By using deletion mutants of Hsp110 protein, a diverged Hsp70 family member, RNA binding was localized to the N-terminal ATP-binding domain of the molecule. The C-terminal peptide-binding domain did not bind RNA, but its engagement by a peptide substrate abrogated RNA binding by the N terminus of the protein. Interestingly, removal of the C-terminal alpha-helical structure or the alpha-loop domain unique to Hsp110 immediately downstream of the peptide-binding domain, but not both, resulted in considerably increased RNA binding as compared with the wild type protein. Finally, a 70-kDa activity was immunoprecipitated from RNA-protein complexes formed in vitro between cytoplasmic proteins of human lymphocytes and AU-rich RNA. These findings support the idea that certain heat shock proteins may act as RNA-binding entities in vivo to guide the appropriate folding of RNA substrates for subsequent regulatory processes such as mRNA degradation and/or translation. |
366 | What is Prudent Diet? | The Prudent dietary pattern is characterised by high intakes of vegetables, fruits, whole grain products and low intakes of refined grain products, legumes, fish, poultry. Generally recommendations are to use saturated/trans fat intake less than 10% of total calories and cholesterol less than 300 mg/day and/or fiber intake ≥ 25 g/day in women and ≥ 35 grams per day in men. | [23639938, 22717188, 23953031, 11493127, 23530637, 3886611, 1852180, 4072955, 23398686, 20624672, 17076904, 7870637, 22914994, 1511475, 23933622, 15539255, 21676220, 15853117, 422845, 216895, 22835136, 2173390, 18796495, 22034645, 207959, 3819235, 6622440, 16580586, 23885043, 23741179, 23524862] | 473 | Studying empirically derived dietary patterns is useful in understanding dietary practice. We classified women by their dietary patterns using latent class analysis of 66 foods and studied the association of these patterns with neural tube defects (NTDs) and congenital heart defects (CHDs) in the U.S. National Birth Defects Prevention Study (1997-2005). Logistic regression models used data from 1,047 with an NTD, 6,641 with a CHD, and 6,123 controls that were adjusted for maternal characteristics and tested the effect modification of multivitamin supplement use. Four latent dietary patterns were identified: prudent, Western, low-calorie Western, and Mexican. Among participants who did not use supplements, those in the Mexican, Western, and low-calorie Western classes were significantly more likely (odds ratios of 1.6, 1.5, and 1.4, respectively) to have offspring born with NTDs than were those in the prudent class after adjustment of for dietary folic acid intake. In contrast, among supplement users, there was no difference in the incidence of NTDs between classes. Associations between dietary class and CHD subgroups were not modified by supplement use except for tetralogy of Fallot; among supplement users, those in the Western class were twice as likely (95% confidence interval: 1.4, 2.8) as the prudent class to have offspring with tetralogy of Fallot. Women who adhered to a Western diet were 1.2 (95% confidence interval: 1.03, 1.35) times more likely to have an infant with septal heart defect than were women who adhered to a prudent diet. A prudent dietary pattern, even with folate fortification, may decrease the risk of NTDs and some heart defects. OBJECTIVE: To review the epidemiological evidence for vegetarian diets, low-meat dietary patterns and their association with health status in adults. DESIGN: Published literature review focusing primarily on prospective studies and meta-analyses examining the association between vegetarian diets and health outcomes. RESULTS: Both vegetarian diets and prudent diets allowing small amounts of red meat are associated with reduced risk of diseases, particularly CHD and type 2 diabetes. There is limited evidence of an association between vegetarian diets and cancer prevention. Evidence linking red meat intake, particularly processed meat, and increased risk of CHD, cancer and type 2 diabetes is convincing and provides indirect support for consumption of a plant-based diet. CONCLUSIONS: The health benefits of vegetarian diets are not unique. Prudent plant-based dietary patterns which also allow small intakes of red meat, fish and dairy products have demonstrated significant improvements in health status as well. At this time an optimal dietary intake for health status is unknown. Plant-based diets contain a host of food and nutrients known to have independent health benefits. While vegetarian diets have not shown any adverse effects on health, restrictive and monotonous vegetarian diets may result in nutrient deficiencies with deleterious effects on health. For this reason, appropriate advice is important to ensure a vegetarian diet is nutritionally adequate especially for vulnerable groups. BACKGROUND: Although substantial information on individual nutrients or foods and risk of coronary heart disease (CHD) is available, little is known about the role of overall eating pattern. METHODS: Using dietary information from a food frequency questionnaire in 1984 from the Nurses' Health Study, we conducted factor analysis and identified 2 major dietary patterns-"prudent" and "Western"-and calculated factor scores of each pattern for individuals in the cohort. We used logistic regression to examine prospectively the associations between dietary patterns and CHD risk among 69 017 women aged 38 to 63 years in 1984 without history of major chronic diseases. RESULTS: The prudent pattern was characterized by higher intakes of fruits, vegetables, legumes, fish, poultry, and whole grains, while the Western pattern was characterized by higher intakes of red and processed meats, sweets and desserts, french fries, and refined grains. Between 1984 and 1996, we documented 821 CHD cases. After adjusting for coronary risk factors, the prudent diet score was associated with a relative risk (RR) of 0.76 (95% confidence interval (CI), 0.60-0.98; P for trend test,.03) comparing the highest with lowest quintile. Extreme quintile comparison yielded an RR of 1.46 (95% CI, 1.07-1.99; P for trend test,.02) for the Western pattern. Those who were jointly in the highest prudent diet quintile and lowest Western diet quintile had an RR of 0.64 (95% CI, 0.44-0.92) compared with those with the opposite pattern profile. CONCLUSION: A diet high in fruits, vegetables, whole grains, legumes, poultry, and fish and low in refined grains, potatoes, and red and processed meats may lower risk of CHD. In the time period 1996-2004, we conducted a case-control study in Montevideo, Uruguay with the objective of exploring the role of foods and alcoholic beverages in the etiology of cancers of the upper aerodigestive tract (UADT). In brief, 563 male cases and 1099 male controls were frequency matched on age and residence using random sampling. All the participants were drawn from the 4 major public hospitals in Montevideo. We used exploratory factor analysis among controls. Through Scree plot test, the model retained 4 factors, which were labeled as prudent, starchy plants, Western, and drinker. These dietary patterns explained 34.8% of the total variance. Whereas the prudent pattern was inversely associated with UADT cancer [odds ratios (OR) for the upper tertile vs. the lowest one 0.52, 95% confidence intervals 0.32-0.76, P value for trend = 0.0005), the remaining patterns were significantly and positively associated with UADT cancers. We conclude that these patterns were similar among the oral and laryngeal cancers, both in the direction of the ORs and in the magnitude of the associations, suggesting that these cancer sites share the effect of dietary patterns in the etiology of cancer of the upper aerodigestive tract. Risk factor status for cardiovascular disease is affected by life style. Adolescence is a time during which long term life-style habits, including dietary habits, are established. Physicians who treat adolescent patients have a responsibility to be aware of the scientific evidence on the diet-heart question so that they can provide their patients with sound dietary advice. The American Heart Association has recommended that Americans consume a "prudent diet" in which daily consumption of cholesterol is no more than 300 mg with up to 30-35% of calories derived from fat, and less than 10% of calories derived from saturated fat and less than 10% from polyunsaturated fat. This paper reviews this recommendation with particular reference to studies of adolescents. This review centers around four main issues: 1) the estimated effect on serum cholesterol levels of a switch from the usual American diet to the prudent diet; 2) the effect of a predicted decrease in serum cholesterol on the risk of developing cardiovascular disease; 3) evaluation of the evidence of possible adverse effects of the prudent diet; 4) feasibility of the prudent diet. Based on a review of these four issues, the authors feel that the American Heart Association's prudent diet should be strongly recommended for all healthy adolescents. BACKGROUND: The National Cholesterol Education Program (NCEP) recommends a low-saturated-fat, low-cholesterol diet, with weight loss if indicated, to correct elevated plasma cholesterol levels. Weight loss accomplished by simple caloric restriction or increased exercise typically increases the level of high-density lipoprotein (HDL) cholesterol. Little is known about the effects on plasma lipoproteins of a hypocaloric NCEP diet with or without exercise in overweight people. METHODS: We tested the hypothesis that exercise (walking or jogging) will increase HDL cholesterol levels in moderately overweight, sedentary people who adopt a hypocaloric NCEP diet. We randomly assigned 132 men and 132 women 25 to 49 years old to one of three groups: control, hypocaloric NCEP diet, or hypocaloric NCEP diet with exercise. One hundred nineteen of the men and 112 of the women returned for testing after one year. RESULTS: After one year, the subjects in both intervention groups had reached or closely approached NCEP Step 1 dietary goals and reduced their mean body fat significantly (range of reduction in mean fat weight, 4.0 to 7.8 kg). Weight loss on the NCEP diet alone did not significantly change HDL cholesterol levels in either the men or the women as compared with the subjects in the control group. Plasma levels of HDL cholesterol increased significantly more in the men who exercised and dieted (mean [+/- SE] change, +13 +/- 3 percent) than in the men who only dieted (+2 +/- 3 percent, P less than 0.01) or the men who acted as controls (-4 +/- 2 percent, P less than 0.001). HDL cholesterol levels remained about the same in the women who exercised and dieted (+1 +/- 2 percent); they were higher than in the women who only dieted (-10 +/- 3 percent, P less than 0.01), but not higher than in the controls (-3 +/- 3 percent). CONCLUSIONS: Regular exercise in overweight men and women enhances the improvement in plasma lipoprotein levels that results from the adoption of a low-saturated-fat, low-cholesterol diet. The differential effect of two diets, taken in synchrony with the menstrual cycles for 2 wk each, on serum and bile lipids was investigated in young healthy women. The "normal" diet was high in cholesterol and total fat, and low in polyunsaturated fat and fiber; the "prudent" diet contained a high proportion of polyunsaturated fat and fiber, but was low in cholesterol and total fat; there was little difference in energy content. Both in whole serum and in low-density lipoprotein the concentrations of cholesterol and apolipoprotein B were almost 30% lower with the "prudent" than with the "normal" diet; HDL-cholesterol was 16.3% lower. Triglycerides were increased, only in the very-low-density lipoproteins while cholesterol and apolipoprotein B did not change much in this fraction. The risk to acquire cholesterol gallstones was not less with the use of the "prudent" diet as originally expected. While using the "prudent" diet five of the women had slightly higher lithogenic indices, in two there were much higher values (greater than 25%), and only in three the lithogenic index was unchanged or slightly lower than with the "normal" diet. BACKGROUND: Diet regulates gene expression profiles by several mechanisms. The objective of this study was to examine gene expression in relation with dietary patterns. METHODS: Two hundred and fifty four participants from the greater Quebec City metropolitan area were recruited. Two hundred and ten participants completed the study protocol. Dietary patterns were derived from a food frequency questionnaire (FFQ) by factor analysis. For 30 participants (in fasting state), RNA was extracted from peripheral blood mononuclear cells (PBMCs) and expression levels of 47,231 mRNA transcripts were assessed using the Illumina Human-6 v3 Expression BeadChips®. Microarray data was pre-processed with Flexarray software and analysed with Ingenuity Pathway Analysis (IPA). RESULTS: Two dietary patterns were identified. The Prudent dietary pattern was characterised by high intakes of vegetables, fruits, whole grain products and low intakes of refined grain products and the Western dietary pattern, by high intakes of refined grain products, desserts, sweets and processed meats. When individuals with high scores for the Prudent dietary pattern where compared to individuals with low scores, 2,083 transcripts were differentially expressed in men, 1,136 transcripts in women and 59 transcripts were overlapping in men and women. For the Western dietary pattern, 1,021 transcripts were differentially expressed in men with high versus low scores, 1,163 transcripts in women and 23 transcripts were overlapping in men and women. IPA reveals that genes differentially expressed for both patterns were present in networks related to the immune and/or inflammatory response, cancer and cardiovascular diseases. CONCLUSION: Gene expression profiles were different according to dietary patterns, which probably modulate the risk of chronic diseases. TRIAL REGISTRATION: NCT: NCT01343342. OBJECTIVE: Dietary habits have been associated with the prevalence of the metabolic syndrome and limited data are available in this field for individuals with impaired glucose tolerance. This study focused on the association between major dietary patterns and prevalence of the metabolic syndrome in individuals with impaired glucose tolerance. METHODS: This cross-sectional study was done in 425 subjects 35 to 55 y of age. Dietary data were collected using a food-frequency questionnaire. Blood pressure, waist circumference, glucose, triacylglycerols, and high-density lipoprotein cholesterol were measured and metabolic syndrome was defined based on Adult Treatment Panel III guidelines. RESULTS: Five major dietary patterns were found: a western pattern (high in sweets, butter, soda, mayonnaise, sugar, cookies, tail of a lamb, hydrogenated fat, and eggs), a prudent pattern (high in fish, peas, honey, nuts, juice, dry fruits, vegetable oil, liver and organic meat, and coconuts and low in hydrogenated fat and non-leafy vegetables), a vegetarian pattern (high in potatoes, legumes, fruits rich in vitamin C, rice, green leafy vegetables, and fruits rich in vitamin A), a high-fat dairy pattern (high in high-fat yogurt and high-fat milk and low in low-fat yogurt, peas, and bread), and a chicken and plant pattern (high in chicken, fruits rich in vitamin A, green leafy vegetables, and mayonnaise and low in beef, liver, and organic meat). After adjusting for confounding variables, the western pattern was associated with greater odds of having increased triacylglycerol (odds ratio 1.76, 95% confidence interval 1.01-3.07) and blood pressure (odds ratio 2.62, 95% confidence interval 1.32-5.23). The prudent pattern was positively associated with a prevalence of low high-density lipoprotein cholesterol levels (odds ratio 0.55, 95% confidence interval 0.31-0.96). The vegetarian dietary pattern was inversely associated with a risk of an abnormal fasting blood glucose level (odds ratio 2.26, 95% confidence interval 1.25-4.06). CONCLUSION: Major dietary patterns were significantly associated with the risk of metabolic syndrome. BACKGROUND: Familial history of obesity (FHO) and certain dietary habits are risk factors for obesity. The objectives of this cross-sectional study were 1) to derive dietary patterns using factor analysis in a population of men and women with and without FHO; 2) to compare mean factor scores for each dietary pattern between individuals with and without FHO; and 3) to examine the association between these patterns and anthropometric, lifestyle and sociodemographic variables. METHODS: A total of 197 women and 129 men with a body mass index <30 kg/m2 were recruited. A positive FHO (FHO+) was defined as having at least one obese first-degree relative and a negative FHO (FHO-) as no obese first-degree relative. Dietary data were collected from a food frequency questionnaire. Factor analysis was performed to derive dietary patterns. Mean factor scores were compared using general linear model among men and women according to FHO. Regression analyses were performed to study the relationship between anthropometric, lifestyle and sociodemographic variables, and each dietary pattern. RESULTS: Two dietary patterns were identified in both men and women : the Western pattern characterized by a higher consumption of red meats, poultry, processed meats, refined grains as well as desserts, and the Prudent pattern characterized by greater intakes of vegetables, fruits, non-hydrogenated fat, and fish and seafood. Similar Western and Prudent factor scores were observed in individual with and without FHO. In men with FHO+, the Western pattern is negatively associated with age and positively associated with physical activity, smoking, and personal income. In women with FHO-, the Prudent pattern is negatively associated with BMI and smoking and these pattern is positively associated with age and physical activity. CONCLUSION: Two dietary patterns have been identified among men and women with and without FHO. Although that FHO does not seem to influence the adherence to dietary patterns, results of this study suggest that anthropometric, lifestyle and sociodemographic variables associated with dietary patterns differ according to FHO and gender. The effects of fruit and vegetables in conjunction with low-energy diet as adjuncts to a prudent diet were compared for 6 months in a randomized, single blind trial in the management of 202 group A and 204 group B patients with acute myocardial infarction. Dietary intakes were obtained based on weighing of fruit, vegetable and legume intake and weekly diet diaries. After 6 months of follow-up, mean body weight, waist/hip ratio and glucose intolerance fell significantly in patients in group A compared with those in group B. Body weight declined by 5.3 kg in group A versus 2.2 kg in group B (95% confidence interval of difference (CI) 1.28-4.92), waist/hip ratio decreased by 0.05 in group A and 0.02 in group B (95% CI 0.01-0.10), and glucose intolerance decreased by 0.85 mmol/l in group A versus 0.19 mmol/l in group B (95% CI 0.19-1.21). There was a significant net decrease in serum triglycerides (0.18 mmol/l), systolic and diastolic blood pressures (7.9/4.7 mmHg), and a net increase in high-density lipoprotein cholesterol (0.10 mmol/l). Underlying these changes, group A patients had 393 g/day net increase in the consumption of fruit and vegetables and 1,160 kJ/day net decrease in energy intake compared to these changes in groups. Those who made greater changes in diet also had greater improvements in central obesity, glucose intolerance and in other associated disturbances. In a randomized, single-blind and controlled trial, the effects of the administration of fruits and vegetables (mean 582 vs. 188 g/day) for 12 weeks were compared as adjuncts to a prudent diet in the management of 202 group A and 204 group B patients with acute myocardial infarction (AMI). Fruits and vegetables decreased total serum cholesterol level (26.4 vs. 13.8 mg/dl, p less than 0.01) low-density lipoprotein cholesterol (20.0 vs. 9.8 mg/dl, p less than 0.01), triglycerides (20.6 vs. 10.6 mg/dl, p less than 0.01) and fasting blood glucose (22.4 vs. 12.6 mg/dl, p less than 0.01) levels more significant in the intervention group than changes in the control group. Adherence to dietary advice was assessed by questionnaires. Total adherence score in group A was significantly higher than in group B. Group A patients also had a significantly smaller rise in lactate dehydrogenase cardiac enzyme which indicates that the protective effects of such a diet may be observed within 1 week. There was a significantly greater decrease in mean blood pressure in group A than changes in group B. These data suggest that fruits and vegetables, because of their high soluble dietary fibre and possibly high antioxidant contents, may be a useful and safe adjunct to a prudent diet in the treatment of patients with AMI. The use of fruits and vegetables may be preferred over oat bran, psyllium and guar gum because of their high content of vitamins and minerals. BACKGROUND: During the year after the Great East Japan Earthquake on March 11, 2011, the health conditions and lifestyles of survivors were extensively surveyed. We examined the relationship between living conditions and dietary pattern among survivors. METHODS: A total of 10 466 survivors aged 18 years or older (25% of the population of that age in the area) participated in a survey of Iwate Prefecture. The average frequency of daily consumption of 8 food groups was determined by questionnaire. After excluding staple foods, which were consumed 3 times a day by 85% of participants, factor analysis was performed on 7 food groups among 9789 people (3795 men, 5994 women). RESULTS: Factor analysis identified 2 dietary patterns-prudent and meat. The prudent dietary pattern is characterized by high intakes of fish and shellfish, soybean products, vegetables, fruit, and dairy products and was more evident among older participants and women. The meat dietary pattern is characterized by high intakes of meat and eggs and was more evident among younger participants and men. Age-adjusted multiple logistic regression analyses showed that male and female current smokers and men and women living in difficult conditions were likely to have a lower prudent dietary pattern score; male current smokers and male daily alcohol drinkers were likely to have a higher meat dietary pattern score. CONCLUSIONS: During the year after the earthquake, the prudent dietary pattern was associated with better living conditions among survivors, whereas the meat dietary pattern was not. In this two-phase crossover study, 39 hypercholesterolemic subjects followed a prudent diet with either lean red meat or fish and skinless chicken (treatment groups), and 13 subjects (reference group) followed their habitual diet. Fasting blood samples were analyzed for plasma total cholesterol, triacylglycerol (TAG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein one- and two-cholesterol, apolipoprotein-B, very low density lipoprotein cholesterol, and very low density lipoprotein TAG, and fatty acid composition of plasma TAG and cholesteryl ester (CE). Body mass and blood pressure were determined. Seven-day dietary records were kept once at baseline and twice during the treatment periods. Significant differences were observed in dietary intake between the baseline and treatment diets and between the two treatment diets. HDL-C (P < 0.05) and diastolic blood pressure (P < 0.01) were higher in patients on the red meat diet than in those on the chicken-fish diet. No other significant differences in lipoproteins were observed between the effects of the two treatment diets. The linoleic acid (%), eicosapentaenoic acid (%), and the eicosapentaenoic acid/arachidonic acid ratios in TAG and CE were higher (P < 0.01) in subjects on the chicken-fish diet than in those on the red meat diet. In conclusion, this study showed that the effect of two lipid-lowering diets containing either lean red meat or skinless chicken and fish on the atherogenic lipoproteins did not differ significantly. A prudent diet with skinless chicken and fish, however, had a more favorable effect on the fatty acid composition of the plasma TAG and the CE than did the lean red meat diet. BACKGROUND: Studies addressing the effects of aerobic exercise and a prudent diet on lipid and lipoprotein concentrations in adults have reached conflicting conclusions. The purpose of this study was to determine the effects of aerobic exercise combined with a prudent diet on lipid and lipoprotein concentrations in adults. METHODS: Studies were located by searching nine electronic databases, cross-referencing, and expert review. Two independent reviewers selected studies that met the following criteria: (1) randomized controlled trials, (2) aerobic exercise combined with diet recommendations (saturated/trans fat intake less than 10% of total calories and cholesterol less than 300 mg/day and/or fiber intake ≥ 25 g/day in women and ≥ 35 grams per day in men), (3) intervention ≥ 4 weeks, (4) humans ≥ 18 years of age, (5) published studies, including dissertations and Master's theses, (6) studies published in any language, (7) studies published between January 1, 1955 and May 1, 2009, (8) assessment of one or more of the following lipid and lipoprotein concentrations: total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), ratio of TC to HDL-C, non-HDL-C, low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG). Two reviewers independently extracted all data. Random-effects models that account for heterogeneity and 95% confidence intervals were used to pool findings. RESULTS: Of the 1,401 citations reviewed, six studies representing 16 groups (8 intervention, 8 control) and up to 559 men and women (282 intervention, 277 control) met the criteria for analysis. Statistically significant intervention minus control reductions were found for TC (-15.5 mg/dl, 95% CI, -20.3 to -10.7), TC:HDL-C (-0.4 mg/dl, 95% CI, -0.7 to -0.2), LDL-C (-9.2 mg/dl, 95% CI, -12.7 to -5.8) and TG (-10.6 mg/dl, 95% CI, -17.2 to -4.0) but not HDL-C (-0.5 mg/dl, 95% CI, -4.0 to 3.1). Changes were equivalent to reductions of 7.5%, 6.6%, 7.2% and 18.2% respectively, for TC, TC:HDL-C, LDL-C and TG. Because of missing variance statistics, non-HDL-C was excluded. CONCLUSIONS: Aerobic exercise combined with a prudent diet is highly efficacious for improving TC, TC:HDL-C, LDL-C and TG, but not HDL-C concentrations, in adults. However, additional studies are needed, including effectiveness studies using intention-to-treat analysis. Nutritional factors in the aetiology of coronary heart disease, maturity-onset diabetes, diverticular disease and dental caries are discussed. Four principles for a prudent diet are suggested, namely: avoid excess intake of energy, increase dietary fibre intake, reduce total fat intake to approximately 30 per cent of energy intake, take a high proportion of fat as the polyunsaturated form. If patients with hyperlipoproteinemia type IIa are treated with diet and additionally over a period of two weeks with 2 grams of Clofibrate daily, the cholesterol-level in the serum decreases. This decrease is caused mainly by a reduction of the apolipoprotein B and the LDL-cholesterol in serum. If elevated cholesterol-levels in the serum are reduced through a "prudent" diet, the concentration of apolipoprotein B in serum remains the same. It is not fully understood which influence a diet, which is rich in poly-unsaturated fatty acids and has a low content of saturated fatty acids and carbohydrates, has upon the lipoproteins in the serum. The mode of action of this diet and its significance for the concentration of HDL need further investigation. Stroke is the fourth leading cause of mortality in the United States, yet it is 80% preventable by addressing lifestyle factors including nutrition. Evaluating the impact of nutrition at the food group and dietary pattern level will provide greater insight into the role of nutrition in stroke. For this purpose, a review of the literature was conducted using the PubMed, Web of Science, and CINAHL Plus online databases. While fruits, vegetables, and soy demonstrated a protective effect, variable findings were observed for fish, animal products, and whole grains. Adherence to DASH, Mediterranean, and prudent dietary patterns reduced the risk of stroke, whereas the Western dietary pattern was associated with increased stroke risk. Low-fat diet was not found to have a protective effect. Additional epidemiological evidence is needed to elucidate the impact of specific dietary patterns and food groups on stroke. Future research should consider developing dietary recommendations for stroke prevention, which are based on clinical trials and have an emphasis on food groups and dietary patterns that are palatable to the general public. Soluble-fiber breakfast cereals were examined for their cholesterol-lowering ability in 58 male patients with mild to moderate hypercholesterolemia in a randomized, double-blind, placebo-controlled study. Patients followed a step 1 diet for a minimum of 6 wk, then were randomly assigned to groups incorporating either corn flakes or one of two soluble-fiber cereals (pectin enriched or psyllium enriched) in the diet for an additional 6 wk. During the diet-only phase, total cholesterol dropped 3.8%. During the cereal-plus-diet phase, total and LDL cholesterol values of the pectin-enriched cereal group dropped an additional 2.1% (P = 0.243) and 3.9% (P = 0.16), respectively, and they dropped 5.9% (P = 0.005) and 5.7% (P = 0.034), respectively, in the psyllium-enriched cereal group. During the cereal-plus-diet phase, no significant effects on HDL cholesterol, triglyceride, or body weight were found within or between any cereal groups. These results support use of soluble-fiber cereals as an effective and well-tolerated part of a prudent diet in the treatment of mild to moderate hypercholesterolemia. OBJECTIVE: To evaluate the impact of combinations of lifestyle factors on mortality in middle aged women. DESIGN: Prospective cohort study. SETTING: Nurses' health study, United States. PARTICIPANTS: 77 782 women aged 34 to 59 years and free from cardiovascular disease and cancer in 1980. MAIN OUTCOME MEASURE: Relative risk of mortality during 24 years of follow-up in relation to five lifestyle factors (cigarette smoking, being overweight, taking little moderate to vigorous physical activity, no light to moderate alcohol intake, and low diet quality score). RESULTS: 8882 deaths were documented, including 1790 from cardiovascular disease and 4527 from cancer. Each lifestyle factor independently and significantly predicted mortality. Relative risks for five compared with zero lifestyle risk factors were 3.26 (95% confidence interval 2.45 to 4.34) for cancer mortality, 8.17 (4.96 to 13.47) for cardiovascular mortality, and 4.31 (3.51 to 5.31) for all cause mortality. A total of 28% (25% to 31%) of deaths during follow-up could be attributed to smoking and 55% (47% to 62%) to the combination of smoking, being overweight, lack of physical activity, and a low diet quality. Additionally considering alcohol intake did not substantially change this estimate. CONCLUSIONS: These results indicate that adherence to lifestyle guidelines is associated with markedly lower mortality in middle aged women. Both efforts to eradicate cigarette smoking and those to stimulate regular physical activity and a healthy diet should be intensified. We aimed to evaluate the effect of the Mediterranean diet (MD) compared with a prudent diet (PD) combined with physical activity on obese obstructive sleep apnoea syndrome (OSAS) patients who were treated with continuous positive airway pressure. 900 patients were evaluated and 40 obese patients (body mass index ≥ 30.0 kg · m(-2)) who met the inclusion criteria, with moderate-to-severe OSAS (apnoea-hypopnoea index (AHI) >15 events · h(-1) and Epworth Sleepiness Scale score >10) based on overnight attended polysomnography, were included in the study. After randomisation, 20 patients followed the MD and 20 a PD for a 6-month period. All patients were counselled to increase their physical activity. Concerning sleep parameters, only AHI during rapid eye movement (REM) sleep was reduced to a statistically significant degree, by mean ± SD 18.4 ± 17.6 events · h(-1) in the MD group and by 2.6 ± 23.7 events · h(-1) in the PD group (p<0.05). The MD group also showed a greater reduction in waist circumference (WC) (-8.7 ± 3.6 cm), WC/height ratio (-0.04 ± 0.02 cm · m(-1)) and WC/hip ratio (-0.04 ± 0.03 cm · cm(-1)), compared with the other group (-2.6 ± 1.7 events · h(-1), -5.7 ± 3.8 cm, -0.03 ± 0.02 cm · m(-1) and 0.02 ± 0.02 cm · cm(-1), respectively; p<0.05). Our results showed that the MD combined with physical activity for a 6-month period was effective in reducing the AHI during REM sleep without any statistically significant effect in the other sleep parameters, compared with a PD in obese adults with moderate-to-severe OSAS. 14 previously untreated patients with hyperlipoproteinemia type IIa according to Fredrickson underwent a controlled clinical trial. The study was designed to clarify the effects of clofibrate on the bloodlipids. All patients were willing to cooperate. After leaving their usual dietary habits all of them were given for seven to ten days a "prudent" diet. This diet was rich in vitamins; it had a low caloric-content. 20% of the calories consisted of proteins, 35% of carbohydrates (sweets were omitted) and about 45% of fats with a PS-factor of about 2.2. After the initial dietary treatment all patients were given twice daily for 14 days 500 mg clofibrate. During the use of the "prudent" diet the serum-cholesterol-levels decreased in average with 14.8%. Compared to the values at the beginning of the trial the difference was statistically highly significant. The average-values of triglycerides, phosphatides and the relative percentage of HDL, LDL and VLDL remained unchanged. After the patients received clofibrate there was an additional decrease of the serum-cholesterol-values of 14.8%. The total decrease of the cholesterol-levels compared to the initial values amounted to 27.4%. Furthermore, there was a reduction of the phosphatids in the serum of 14.1% compared to the initial value and of 9.9% compared to the value after dietary treatment alone. Under the combined effects of a "prudent" diet with clofibrate the HDL increased significantly. It can be assumed that clofibrate reduces the serum-cholesterol-levels in cases of hyperlipoproteinemia by decreasing the LDL-fraction, which is rich in cholesterol, and by increasing the HDL-fraction. To evaluate the effect on longevity of a diet that is concurrent with common dietary guidelines, a simple diet scoring system was developed and applied in a follow-up study of 2,820 middle-aged Dutch civil servants and their spouses. In the early 1950s those civil servants were seen for a health examination that included a dietary survey. Consumption frequency data of the quantitatively most important food items at that time were used for the diet scoring. Overall survival after 25 years was 46.8% among men and 68.6% among women. In men, a significant positive association between prudent diet score and 25-year, age-adjusted survival could be demonstrated. Of the 10 food items that constituted the diet score, a higher intake of brown bread, porridge and/or yogurt, vegetables, fish, and fruit was associated with a slightly better survival. In a separate analysis we had found a significant inverse relationship between coffee consumption and survival. A similar trend, which, however, was not significant, was observed for alcohol intake. In women, the results for the separate food items were inconsistent, and no effect of a prudent diet score on longevity was observed. The proposed diet scoring system provides a means for evaluating the effects of the individual's food choice behavior on subsequent health and longevity. "Product sampling" is an effective marketing strategy which lowers consumer buying resistance by providing a free sample of the product for the consumer to test. We used this strategy to demonstrate the palatability of the prudent diet (30-35% of calories from total fats, less than 10% from saturated fats, less than 3 g sodium, and increased fiber) to physicians attending a 5-day family practice continuing medical education conference. The effect of the intervention was evaluated with pre- and postintervention questionnaires and a 20% random sample of participants was surveyed 1 year later. The proportion of physicians who reported that they considered the diet to be "very palatable" rose from 26% before the demonstration to 64% after the demonstration. Only 5% of the physicians did not report a favorable response to the demonstration. Sixty-two percent of the physicians reported that the diet was better than expected, and 82% reported that the demonstration encouraged them to recommend the diet to their patients. One year after the intervention 60% considered the diet "very palatable" and 55% reported that the demonstration stimulated them to increase their dietary intervention activities. These data suggest that serving the prudent diet at continuing medical education programs helps to remove prejudices about the diet and encourages physicians to recommend the diet to their patients. INTRODUCTION: Epidemiological studies have shown that dietary behaviour is an important aetiological factor in various chronic diseases. We used principal component factor analysis to identify dietary patterns and to examine the associations of these patterns with health-related variables in a sample of elderly (> or =60 years) Italians participating in the European Prospective Investigation into Cancer and Nutrition (EPIC). METHODS AND RESULTS: Exploratory factor analysis was applied to the intake of food groups as estimated by semi-quantitative food questionnaires. Individual participants were assigned factor scores, indicating the extent to which their diet conformed to each of the four dietary patterns identified: prudent (cooked vegetables, pulses, cabbage, seed oil and fish); pasta & meat (pasta, tomato sauce, red meat, processed meat, bread and wine); olive oil & salad (raw vegetables, olive oil, soup and chicken); and sweet & dairy (sugar, cakes, ice cream, coffee and dairy). Highly educated people had high scores on prudent and low scores on pasta & meat. The pasta & meat and prudent patterns were strongly positively associated with body mass index (BMI) and waist-to-hip ratio (WHR) in men and women. Hyperlipidaemic men and women consumed more of the prudent and olive oil & salad patterns and less of the sweet & dairy pattern than those with normal lipids. The olive oil & salad was significantly higher and the pasta & meat and sweet & dairy patterns significantly lower in men and women who had dieted over the previous year, suggesting awareness of the health consequences of these patterns. CONCLUSIONS: Dietary pattern analysis provides a characterization of recurrent dietary behaviour in elderly people, and can be used to provide tangible dietary advice to elderly people. BACKGROUND: Although individual nutrients have been investigated in relation to depression risk, little is known about the overall role of diet in depression. OBJECTIVE: We examined whether long-term dietary patterns derived from a food-frequency questionnaire (FFQ) predict the development of depression in middle-aged and older women. DESIGN: We conducted a prospective study in 50,605 participants (age range: 50-77 y) without depression in the Nurses' Health Study at baseline (1996) who were followed until 2008. Long-term diet was assessed by using FFQs every 4 y since 1986. Prudent (high in vegetables) and Western (high in meats) patterns were identified by using a principal component analysis. We used 2 definitions for clinical depression as follows: a strict definition that required both a reported clinical diagnosis and use of antidepressants (3002 incident cases) and a broad definition that further included women who reported either a clinical diagnosis or antidepressant use (7413 incident cases). RESULTS: After adjustment for age, body mass index, and other potential confounders, no significant association was shown between the diet patterns and depression risk under the strict definition. Under the broad definition, women with the highest scores for the Western pattern had 15% higher risk of depression (95% CI: 1.04, 1.27; P-trend = 0.01) than did women with the lowest scores, but after additional adjustment for psychological scores at baseline, results were no longer significant (RR: 1.09; 95% CI: 0.99, 1.21; P-trend = 0.08). CONCLUSION: Overall, results of this large prospective study do not support a clear association between dietary patterns from factor analysis and depression risk. Comment on Microbiological profile and nutritional quality of raw foods for neutropenic patients under hospital care. :94–98. BACKGROUND: Declines in gastric cancer (GC) incidence and mortality have been related to improvements in diet. It is therefore important to consider dietary patterns. DESIGN: We conducted a systematic review and meta-analysis of the literature through Medline and Embase databases. RESULTS: We identified 16 papers, of these 9 derived dietary patterns through an a posteriori method, 5 through a priori scores, and 2 used both approaches. Eight studies that used the a posteriori approach were considered for the meta-analysis. A favorable role on GC emerged for the 'Prudent/healthy', with an odds ratio (OR) of 0.75 [95% confidence interval (CI): 0.63-0.90], for the highest versus the lowest category. Similar results emerged for separate anatomical subtypes. An unfavorable role on GC emerged for the 'Western/unhealthy' dietary pattern, with an OR of 1.51 (95% CI: 1.21-1.89). This association was weaker for the distal/NOS (not otherwise specified) category (OR = 1.36) compared with the cardia GC (OR = 2.05). Among the a priori scores, the ORs ranged from 0.2 to 0.7 for the favorable and from 1.8 to 6.9 for the unfavorable ones. CONCLUSION: There is a ~2-fold difference in GC risk between a 'Prudent/healthy' diet-rich in fruits and vegetables, and a 'Western/unhealthy' diet-rich in starchy foods, meat and fats. |
367 | What is the role of necroptosis in cancer therapy? | Necroptosis, a novel form of programmed cell death (PCD), is caspase independent but RIPK and RIPK3 dependent. The apoptotic, autophagic and necroptotic pathways of PCD were shown to be interconnected, with molecules such as FLIP acting as a bridge between them. Therefore, simultaneous activation of the three PCD pathways would make cancer therapy more effective, whereas induction of necroptosis could be an alternative, in cases where apoptosis-inducing cancer chemotherapy is not effective. For example, inhibition of GSK3B was found to bypass drug resistance of p53-null colon carcinomas by enabling necroptosis in response to 5-FU treatment. | [23301705, 23875666, 23625539, 23729362] | 474 | Programmed cell death plays an important role in animal development, tissue homeostasis and eliminating harmful or virally infected cells. Necroptosis, a novel form of programmed cell death, is caspase independent but RIPK and RIPK3 dependent. Moreover, it is suggested that necroptosis can be specifically inhibited by small molecular inhibitors such as necrostatin-1. Its signaling pathways have something in common with apoptosis, although the molecular mechanisms of necroptosis need to be further elucidated. Previous evidences suggest that necroptosis has significant effects in regulating various physiological processes and disease, such as ischemic brain injury, immune system disorders and cancer. In this review, the molecular mechanism of necroptosis is described and how it could be manipulated in the treatment of cancer is summarized. Cancerous growth is one of the most difficult diseases to target as there is no one clear cause, and targeting only one pathway does not generally produce quantifiable improvement. For a truly effective cancer therapy, multiple pathways must be targeted at the same time. One way to do this is to find a gene that is associated with several pathways; this approach expands the possibilities for disease targeting and enables multiple points of attack rather than one fixed point, which does not allow treatment to evolve over time as cancer does. Inducing programmed cell death (PCD) is a promising method to prevent or inhibit the progression of tumor cells. Intricate cross talk among various programmed cell death pathways including cell death by apoptosis, necroptosis or autophagy plays a critical role in the regulation of PCD. In addition, the complex and overlapping patterns of signaling and lack of understanding of such networks between these pathways generate hurdles for developing effective therapeutic approaches. This review article focuses on targeting FLIP (Fas-associated death domain-like interleukin-1-converting enzyme-like inhibitory protein) signaling as a bridge between various PCD processes as an effective approach for cancer management. PURPOSE: Evasion from chemotherapy-induced apoptosis due to p53 loss strongly contributes to drug resistance. Identification of specific targets for the treatment of drug-resistant p53-null tumors would therefore increase the effectiveness of cancer therapy. EXPERIMENTAL DESIGN: By using a kinase-directed short hairpin RNA library and HCT116p53KO drug-resistant colon carcinoma cells, glycogen synthase kinase 3 beta (GSK3B) was identified as a target whose silencing bypasses drug resistance due to loss of p53. p53-null colon cancer cell lines with different sets of mutations were used to validate the role of GSK3B in sustaining resistance and to characterize cell death mechanisms triggered by chemotherapy when GSK3B is silenced. In vivo xenograft studies were conducted to confirm resensitization of drug-resistant cells to chemotherapy upon GSK3 inhibition. Colon cancer samples from a cohort of 50 chemotherapy-treated stage II patients were analyzed for active GSK3B expression. RESULTS: Downregulation of GSK3B in various drug-resistant p53-null colon cancer cell lines abolished cell viability and colony growth after drug addition without affecting cell proliferation or cell cycle in untreated cells. Cell death of 5-fluorouracil (5FU)-treated p53-null GSK3B-silenced colon carcinoma cells occurred via PARP1-dependent and AIF-mediated but RIP1-independent necroptosis. In vivo studies showed that drug-resistant xenograft tumor mass was significantly reduced only when 5FU was given after GSK3B inhibition. Tissue microarray analysis of colon carcinoma samples from 5FU-treated patients revealed that GSK3B is significantly more activated in drug-resistant versus responsive patients. CONCLUSIONS: Targeting GSK3B, in combination with chemotherapy, may represent a novel strategy for the treatment of chemotherapy-resistant tumors. |
368 | Can venlafaxine block NET and SERT? | Yes, venlafaxine inhibits both the NET and SERT. | [23090625, 10490914, 11524036, 11454918, 9400006, 12784104, 9252010, 18923402, 10884561, 18538356, 16140280, 15989562, 18418363] | 475 | INTRODUCTION: Serotonin and norepinephrine reuptake inhibitors (SNRIs) are antidepressants which have high affinity to both serotonin transporter (SERT) and norepinephrine transporter (NET). In studies in vitro, SNRIs have been reported to show a large variability in the affinity ratio between SERT and NET. For instance, the reported affinity ratio is about 30 for venlafaxine and 1.6 for milnacipran. In this study in nonhuman primates, we aimed to investigate the relationship between SERT and NET affinity by measuring the in vivo occupancy at both transporters of venlafaxine and milnacipran. METHODS: PET measurements with [(11)C]MADAM and [(18)F]FMeNER-D(2) were performed in two female cynomolgus monkeys at baseline and after pretreatment with venlafaxine and milnacipran, respectively. Relationships between dose, plasma concentration, and transporter occupancy were evaluated by saturation analysis using a hyperbolic function. Binding affinity (Kd(plasma)) was expressed by the dose or plasma concentration at which 50 % of the transporter was occupied. RESULTS: SERT and NET occupancy by venlafaxine and milnacipran increased in a dose and plasma concentration-dependent manner. The Kd(plasma) ratio of SERT to NET was 1.9 for venlafaxine and 0.6 for milnacipran. CONCLUSIONS: In this nonhuman primate PET study, the affinity in vivo for SERT and NET, respectively, was shown to be at a similar level for venlafaxine and milnacipran. Both drugs were found to produce balanced inhibition of SERT and NET binding. This observation is not consistent with previous in vitro binding data and illustrates the need to characterize antidepressants at in vivo condition. Venlafaxine is a newly introduced antidepressant agent. The drug causes selective inhibition of neuronal reuptake of serotonine and norepinephrine with little effect on other neurotransmitter systems. Cases of seizures, tachycardia, and QRS prolongation have been observed following drug overdose in humans. The clinical manifestations of cardiac toxicity suggest that venlafaxine may exhibit cardiac electrophysiological effects on fast conducting cells. Consequently, studies were undertaken to characterize effects of venlafaxine on the fast inward sodium current (I(Na)) of isolated guinea pig ventricular myocytes. Currents were recorded with the whole-cell configuration of the patch-clamp technique in the presence of Ca(2+) and K(+) channel blockers. Results obtained demonstrated that venlafaxine inhibits peak I(Na) in a concentration-dependent manner with an estimated IC(50) of 8. 10(-6) M. Inhibition was exclusively of a tonic nature and rate-independent. Neither kinetics of inactivation (tau(inac)= 0.652 +/- 0.020 ms, under control conditions; tau(inac)= 0.636 +/- 0.050, in the presence of 10(-5) M venlafaxine; n = 5 cells isolated from five animals) nor kinetics of recovery from inactivation of the sodium channels (tau(re)= 58.7 +/- 1.6 ms, under control conditions; tau(re)= 54.4 +/- 1.8, in the presence of 10(-5) M venlafaxine; n = 10 cells isolated from six animals) were significantly altered by 10(-5) M venlafaxine. These observations led us to conclude that venlafaxine blocks I(Na) following its binding to the resting state of the channel. Thus, the characteristics of block of I(Na) by venlafaxine are different from those usually observed with most tricyclic antidepressants or conventional class I antiarrhythmic drugs. S33005 displayed marked affinity for native, rat, and cloned human serotonin (5-HT) transporters (SERT) and less pronounced affinity for norepinephrine (NE) transporters (NET), while its affinity at dopamine (DA) transporters and >50 other sites was negligible. Reuptake of 5-HT and (less potently) NE into cerebral synaptosomes was inhibited by S33005, whereas DA reuptake was little affected. In vivo, S33005 prevented depletion of cerebral pools of 5-HT by parachloroamphetamine. Furthermore, it decreased electrical activity of raphe-localized serotonergic neurones, an action abolished by the 5-HT1A antagonist WAY100,635. At higher doses, S33005 blocked firing of locus ceruleus-localized adrenergic neurones, an action abolished by the alpha2-adrenergic antagonist idazoxan. In contrast, S33005 did not inhibit ventrotegmental dopaminergic neurones. In frontal cortex of freely moving rats, S33005 dose dependently elevated dialysate levels of 5-HT, NE, and DA. In hippocampus, levels of 5-HT and NE were similarly elevated, while in nucleus accumbens and striatum, levels of 5-HT were increased whereas DA was unaffected. Upon chronic (2 weeks) administration, basal levels of NE were elevated in frontal cortex and, therein, 5-HT2A receptor density was decreased. Comparative studies with clinically used antidepressants showed that venlafaxine possessed a profile similar to S33005 but was less potent. Clomipramine likewise interacted with SERTs and NETs but also with several other receptors types, while citalopram and reboxetine were preferential ligands of SERTs and NETs, respectively. In conclusion, S33005 interacts potently with SERTs and, less markedly, with NETs. It enhances extracellular levels of 5-HT and NE throughout corticolimbic structures and selectively elevates dialysis levels of DA in frontal cortex versus subcortical regions. Weight-restored patients with anorexia nervosa (AN) respond favorably to the selective serotonin reuptake inhibitor fluoxetine, which justifies association studies of the serotonin transporter gene (SLC6A4, alias SERT) and AN. Case-control studies suggest that the least transcriptionally active allele of the SERT gene promoter polymorphism (5-HTTLPR) has an increased frequency in AN patients. However, this finding was not replicated with 55 trios (AN child+parents) and the transmission disequilibrium test (TDT). To clarify the role of the 5-HTTLPR in susceptibility to AN, we used the TDT and 106 Australian trios to provide 93% power to detect a genotypic relative risk (GRR) of 2.0. Our results were negative for this GRR (McNemar's chi(2)=0.01, df=1, p=0.921, odds ratio 1.0, 95% CI 0.7-1.5). Additionally, we found no association with AN females, AN subtype, age at onset, or minimum BMI. We then performed the first reported investigation of epistasis between the SERT gene and norepinephrine transporter gene (SLC6A2, alias NET) in AN, as an earlier study suggested that atypical AN responds to the dual serotonin-norepinephrine reuptake inhibitor venlafaxine. We observed no epistasis between the 5-HTTLPR and a polymorphism within the NET gene promoter polymorphic region (NETpPR) (chi(2)=0.48, df=1, p=0.490). Although 5-HTTLPR modulates serotonin reuptake by the serotonin transporter, our analyses provide no evidence that susceptibility to AN is modified by 5-HTTLPR alone, nor in concert with as yet undetermined functional effects of the NETpPR polymorphism. Venlafaxine hydrochloride (Effexor) is a structurally novel antidepressant that inhibits reuptake of 5-hydroxytryptamine and noradrenaline, but unlike the older antidepressants, has few side-effects. The objective of this study was to determine whether venlafaxine relieves thermal hyperalgesia in rats with neuropathic pain due to chronic constriction injury (CCI) of the sciatic nerve. Paw withdrawal latency (PWL) to heat was tested for each hind paw. A painful neuropathy was induced in 24 male Sprague-Dawley rats (Group 1) as described by Bennett and Xie. Rats randomly received either oral venlafaxine (22 mg/kg) or placebo via gavage feeding beginning the day after surgery. Postoperative PWL testing began 3 days after CCI (Time 0). A second group of 12 rats (Group 2) was used to confirm that venlafaxine reverses hyperalgesia in rats with a fully developed neuropathic lesion. These animals began to receive oral venlafaxine (22 mg/kg) starting on the third postoperative day, after the presence of thermal hyperalgesia was verified through PWL testing. Testing was continued for 5 days, during venlafaxine administration. A third group of 12 rats (Group 3) had activity measured before and after treatment with venlafaxine (22 mg/kg). Rats in the placebo group developed thermal hyperalgesia while those that received venlafaxine did not. Venlafaxine also appeared to have a mild non-specific analgesic effect that increased PWL in the sham limb. In Group 2, thermal hyperalgesia was present on day 3, but following treatment with venlafaxine, thermal hyperalgesia resolved. Activity measurements confirmed that venlafaxine was not sedating in this rat model. Previous work has shown that repeated desipramine treatment causes downregulation of the norepinephrine transporter (NET) and persistent antidepressant-like effects on behavior, ie effects observed 2 days after discontinuation of drug treatment when acute effects are minimized. The present study examined whether this mechanism generalizes to other antidepressants and also is evident for the serotonin transporter (SERT). Treatment of rats for 14 days with 20 mg/kg per day protriptyline or 7.5 mg/kg per day sertraline reduced NET and SERT expression, respectively, in cerebral cortex and hippocampus; these treatments also induced a persistent antidepressant-like effect on forced-swim behavior. Increased serotonergic neurotransmission likely mediated the behavioral effect of sertraline, as it was blocked by inhibition of serotonin synthesis with p-chlorophenylalanine; a parallel effect was observed previously for desipramine and noradrenergic neurotransmission. Treatment with 20 mg/kg per day reboxetine for 42, but not 14, days reduced NET expression; antidepressant-like effects on behavior were observed for both treatment durations. Treatment for 14 days with 70 mg/kg per day venlafaxine, which inhibits both the NET and SERT, or 10 mg/kg per day phenelzine, a monoamine oxidase inhibitor, produced antidepressant-like effects on behavior without altering NET or SERT expression. For all drugs tested, reductions of NET and SERT protein were not accompanied by reduced NET or SERT mRNA in locus coeruleus or dorsal raphe nucleus, respectively. Overall, the present results suggest an important, though not universal, role for NET and SERT regulation in the long-term behavioral effects of antidepressants. Understanding the mechanisms underlying transporter regulation in vivo may suggest novel targets for the development of antidepressant drugs. The effect of a 21-day treatment with the dual 5-HT and NE reuptake blocker venlafaxine (delivered s.c. by osmotic minipumps) was assessed on the time required for a 50% recovery (RT(50)) of the firing activity of dorsal hippocampus CA(3) pyramidal neurons from the suppression induced by microiontophoretic applications of 5-HT and NE. The RT(50) values for 5-HT were increased by both 10 and 40 mg/kg/day regimens of venlafaxine, whereas those for NE were increased only by the 40 mg/kg/day regimen, indicative of a greater potency of venlafaxine in blocking 5-HT reuptake. The sensitivity of the postsynaptic 5-HT(1A) and alpha(2)-adrenergic receptors was altered by neither regimen of venlafaxine. Using a paradigm by which the 5-HT(1A) antagonist WAY 100635 can induce a disinhibition of firing activity of CA(3) pyramidal neurons, it was demonstrated that the high, but not the low, dose of venlafaxine led to an enhanced tonic activation of postsynaptic 5-HT(1A) receptors in the dorsal hippocampus. The duration of the suppressant effect of the firing activity of CA(3) hippocampus pyramidal neurons produced by the electrical stimulation of the ascending 5-HT pathway was significantly reduced when the frequency of the stimulation was enhanced from 1 Hz to 5 Hz in control rats and in rats treated with 10 mg/kg/day, but not with 40 mg/kg/day of venlafaxine. Hence, venlafaxine induced a desensitization of the terminal 5-HT(1B) autoreceptor only at the high dose. A 2-day treatment with 10 mg/kg/day of venlafaxine induced a suppression of the firing activity of 5-HT neurons of the dorsal raphe. The firing activity of these neurons was back to control level in rats that had been treated for 21 days with the same dose of venlafaxine. The suppressant effect of the i.v. administration of the 5-HT autoreceptor agonist LSD on the firing activity of dorsal raphe 5-HT neurons was reduced in rats that had been treated for 21 days with 10 mg/kg/day of venlafaxine. A 2-day treatment with 40 mg/kg/day of venlafaxine, unlike the 10 mg/kg/day regimen, induced a marked suppression of the firing activity of locus coeruleus NE neurons. However, in contrast to 5-HT neurons, NE neurons did not recover their firing activity after a 21-day treatment. Taken together, the results from this study indicate that the low dose of venlafaxine blocked selectively the reuptake of 5-HT, whereas the high dose blocked the reuptake of both 5-HT and NE. Moreover, an enhancement of serotonergic neurotransmission by venlafaxine was only achieved under conditions whereby the desensitization of the terminal 5-HT(1B) autoreceptor is appended to that of the somatodendritic 5-HT(1A) receptor. The goal of this study was to develop and validate ex vivo binding assays for serotonin (SERT), norepinephrine (NET) and dopamine (DAT) transporters, and to use these assays to evaluate the binding site occupancy of triple and double monoamine reuptake inhibitors in rat brains. This study demonstrated that while autoradiographic methods provided anatomic precision and regional resolution, the homogenate binding method for site occupancy assessment yielded comparable sensitivity with markedly improved throughput. For ex vivo binding assays, the reduction of temperature and time during the in vitro process (primarily incubation with a radioligand) markedly decreased the dissociation of test agents from binding sites in brain tissues. This reduction, in turn, minimized the potential for underestimation of site occupancy in vivo especially for test compounds with affinity >10nM. The ratios of measured occupancy ED(50) values (doses at which 50% occupancy occurs) among SERT, NET and DAT sites for duloxetine, venlafaxine, nomifensine, indatraline, DOV 21,947 and DOV 216,303 were consistent with the ratios of the in vitro affinities between these target binding sites. The biological relevance of the monoamine transporter occupancy for these compounds is discussed. BACKGROUND: Venlafaxine blocks both serotonin and norepinephrine transporters (SERT and NET), with higher affinity for SERT. Serotonergic effects occur with lower doses, whereas both serotonergic and noradrenergic effects occur with higher doses of venlafaxine. Chronic treatment of rats with selective serotonin reuptake inhibitors decreases SERT binding sites, whereas similar treatment with selective norepinephrine reuptake inhibitors decreases NET binding sites. We hypothesized that venlafaxine would affect monoamine transporters dose-dependently, with low doses causing selective reduction of SERT binding sites and higher doses reducing both SERT and NET binding sites. METHODS: Rats were treated for 21 days with a low (15 mg/kg/day) or high (70 mg/kg/day) dose of venlafaxine, vehicle, or other antidepressants. The SERT and NET density was determined by quantitative autoradiography. RESULTS: Neither dose of venlafaxine nor amitriptyline reduced binding to either the SERT or NET. In rats with noradrenergic terminals destroyed by 6-hydroxydopamine, venlafaxine still failed to reduce SERT binding. Also, rats treated simultaneously with sertraline plus desipramine exhibited reductions in both SERT and NET binding. CONCLUSIONS: Chronic venlafaxine treatment affected SERT and NET binding differently from paroxetine or desipramine. The inability of venlafaxine to reduce SERT or NET binding sites is not due to its dual uptake inhibiting properties. Paroxetine and venlafaxine are potent serotonin transporter (SERT) antagonists and weaker norepinephrine transporter (NET) antagonists. However, the relative magnitude of effect at each of these sites during treatment is unknown. Using a novel blood assay that estimates CNS transporter occupancy we estimated the relative SERT and NET occupancy of paroxetine and venlafaxine in human subjects to assess the relative magnitude of SERT and NET inhibition. Outpatient subjects (N=86) meeting criteria for major depression were enrolled in a multicenter, 8 week, randomized, double-blind, parallel group, antidepressant treatment study. Subjects were treated by forced-titration of paroxetine CR (12.5-75 mg/day) or venlafaxine XR (75-375 mg/day) over 8 weeks. Blood samples were collected weekly to estimate transporter inhibition. Both medications produced dose-dependent inhibition of the SERT and NET. Maximal SERT inhibition at week 8 for paroxetine and venlafaxine was 90% (SD 7) and 85% (SD 10), respectively. Maximal NET inhibition for paroxetine and venlafaxine at week 8 was 36% (SD 19) and 60% (SD 13), respectively. The adjusted mean change from baseline (mean 28.6) at week 8 LOCF in MADRS total score was -16.7 (SE 8.59) and -17.3 (SE 8.99) for the paroxetine and venlafaxine-treated patients, respectively. The magnitudes of the antidepressant effects were not significantly different from each other (95%CI -3.42, 4.54, p=0.784). The results clearly demonstrate that paroxetine and venlafaxine are potent SERT antagonists and less potent NET antagonists in vivo. NET antagonism has been posited to contribute to the antidepressant effects of these compounds. The clinical significance of the magnitude of NET antagonism by both medications remains unclear at present. |
369 | Is Rheumatoid Arthritis more common in men or women? | Disease patterns in RA vary between the sexes; the condition is more commonly seen in women, who exhibit a more aggressive disease and a poorer long-term outcome. | [23217568, 19158113, 22853635, 16418123, 15083883, 21340496, 17965425, 20810033, 12723987, 18759162, 1563036, 20889597] | 476 | BACKGROUND: Data on the effect of gender in rheumatoid arthritis (RA) in non-Caucasian populations is scarce. Latin America and the Caribbean (LAC) is a large population with unique characteristics, including high admixture. OBJECTIVE: Our aim was to examine the effect of gender in patients with RA in LAC. METHODS: This was a 2-phase study. First we conducted a cross-sectional and analytical study in which 1128 consecutive Colombian patients with RA were assessed. Second, a systematic review of the literature was done to evaluate the effect of gender in LAC patients with RA. RESULTS: Our results show a high prevalence of RA in LAC women with a ratio of 5.2 women per man. Colombian women with RA are more at risk of having an early age at onset and developing polyautoimmunity and abdominal obesity, and they perform more household duties than their male counterparts. However, male gender was associated with the presence of extra-articular manifestations. Of a total of 641 potentially relevant articles, 38 were considered for final analysis, in which several factors and outcomes related to gender were identified. CONCLUSIONS: RA in LAC women is not only more common but presents with some clinical characteristics that differ from RA presentation in men. Some of those characteristics could explain the high rates of disability and worse prognosis observed in women with RA in LAC. OBJECTIVE: To evaluate gender differences in score on 28-joint Disease Activity Score (DAS28), Health Assessment Questionnaire (HAQ) and Signals Of Functional Impairment (SOFI) and to relate these scores to radiographic joint destruction. METHODS: In all, 549 patients with early RA (62% women) from the BARFOT (for "Better Anti-Rheumatic FarmacOTherapy") study were included. At baseline, 1, 2 and 5 years DAS28, HAQ and SOFI scoring, and radiographs of hands and feet were performed. The radiographs were scored using the van der Heijde-Sharp score. RESULTS: In women the DAS28 was significantly higher than in men due to higher scores for general health and tender joints. Likewise, HAQ and VAS pain were rated significantly higher in women. The SOFI score was worse in men during the first 2 years, depending on higher upper limb scores. Total Sharp score (TotSharp), erosion score and joint space narrowing score did not differ between the sexes at any time point. The DAS28 area under the curve (AUC) correlated significantly with TotSharp at 5 years in both genders (r = 0.316, r = 0.313) mainly owing to swollen joints and erythrocyte sedimentation rate (ESR). The SOFI AUC correlated significantly with TotSharp in women (r = 0.135 to 0.220) but not in men. CONCLUSIONS: Despite a similar degree of radiographic joint destruction women had, compared with men, worse scores for DAS28 and HAQ, possibly due to higher pain perception and less muscular strength and perhaps because men overestimate their functional capacity. BACKGROUND: Rheumatoid arthritis (RA), inflammatory bowel disease (IBD), and psoriasis are immune-mediated inflammatory diseases with similarities in pathophysiology, and all can be treated with similar biological agents. Previous studies have shown that there are gender differences with regard to disease characteristics in RA and IBD, with women generally having worse scores on pain and quality of life measurements. The relationship is less clear for psoriasis. Because treatment differences between men and women could explain the dissimilarities, we investigated gender differences in the disease characteristics before treatment initiation and in the biologic treatment prescribed. METHODS: Data on patients with RA or IBD were collected from two registries in which patients treated with biologic medication were enrolled. Basic demographic data and disease activity parameters were collected from a time point just before the initiation of the biologic treatment. For patients with psoriasis, the data were taken from the 2010 annual report of the Swedish Psoriasis Register for systemic treatment, which included also non-biologic treatment. For all three diseases, the prescribed treatment and disease characteristics were compared between men and women. RESULTS: In total, 4493 adult patients were included in the study (1912 with RA, 131 with IBD, and 2450 with psoriasis). Most of the treated patients with RA were women, whereas most of the patients with IBD or psoriasis were men. There were no significant differences between men and women in the choice of biologics. At treatment start, significant gender differences were seen in the subjective disease measurements for both RA and psoriasis, with women having higher (that is, worse) scores than men. No differences in objective measurements were found for RA, but for psoriasis men had higher (that is, worse) scores for objective disease activity measures. A similar trend to RA was seen in IBD. CONCLUSIONS: Women with RA or psoriasis scored significantly higher on subjective, but not on objective, disease activity measures than men, and the same trend was seen in IBD. This indicates that at the same level of treatment, the disease has a greater effect in women. These findings might suggest that in all three diseases, subjective measures are discounted to some extent in the therapeutic decision-making process, which could indicate undertreatment in female patients. Emotion regulation has been associated with perceived health in rheumatoid arthritis, which is diagnosed three times more often in women than men. Our aim was to examine gender differences in styles of emotion regulation (ambiguity, control, orientation, and expression) and gender-specificity of the associations between emotion regulation and perceived health (psychological well-being, social functioning, physical functioning, and disease activity) in 244 female and 91 male patients with rheumatoid arthritis. Women reported more emotional orientation than men, but did not differ from men with regard to ambiguity, control, and expression. Structural equation modelling showed that relationships between emotion regulation and perceived health were more frequent and stronger for women than men. This held especially for the affective dimension of health, while associations were similar for both women and men with regard to social and physical functioning. Only for women, the association between ambiguity and disease activity was significant, which appeared to be mediated by affective functioning. The observations that women are more emotionally oriented than men and that emotion regulation is more interwoven with psychological health in women than men, support the usefulness of a gender-sensitive approach in research and health care of patients with rheumatoid arthritis. OBJECTIVE: To investigate whether gender is an independent factor associated with disease expression in early rheumatoid arthritis (RA) patients. METHODS: 438 patients with early RA (disease duration less than one year) were studied. They all were patients with early RA who presented at the Rheumatology Clinic of the University Hospital of Ioannina during the period 1991-2000. All patients fulfilled the American College of Rheumatology criteria for RA. The demographic, clinical, laboratory, radiological and therapeutic characteristics of the disease at diagnosis, and at the last follow-up were analyzed according to gender. RESULTS: We studied 312 women and 126 men with early RA. The female to male ratio was 2.5:1 and the mean age at diagnosis was 49.4 +/- 14.9 years for women and 55.3 +/-15.6 years for men (P < 0.0003). Women had a longer duration of follow-up (P < 0.0003). There were no differences between genders in the general symptoms or the simmetricity of joint involvement at at disease onset. However at disease onset women had a higher erythrocyte sedimentation rate (ESR) (> 30 mm/1st hour), although there were no significant differences between the two groups concerninig the rest of the clinical, laboratory and radiological findings. At the last follow-up women still had a higher ESR (>30 min/1st hour), but no significant differences were found between the two groups concerning the rest of the parameters investigated independently of the follow-up duration. Finally, women and men showed the same degree of radiological changes and functional ability and were treated similarly except for the more frequent use of hydroxychloroquine in women. CONCLUSION: It seems that gender does not signficantly influence the expression of RA. OBJECTIVES: To investigate the influence of age and gender on the components of the 28-joint Disease Activity Score (DAS28) in patients with rheumatoid arthritis (RA), and to clarify whether a high DAS28 can be equally interpreted in all age groups, independent of gender. METHODS: A prospective cohort of 553 patients with RA was studied for approximately 20 years after diagnosis. The single measures of disease activity and the share of different components of the DAS28 (eg, erythrocyte sedimentation rate; ESR) were analysed and compared between three age groups (<45, 45-65 and >65 years) and per gender, using analysis of variance (ANOVA). The performance of the DAS28 and its components was explored in moderate to high and low DAS28 categories. Linear mixed model analysis was used to design the models best predicting ESR and the share of ESR. RESULTS: ESR significantly increased with age, independent of other variables of disease activity. This increase was more pronounced in male than in female patients. Nevertheless, the share of ESR increased with age only in male patients with a low DAS28 (<3.2). If the DAS28 score was >3.2, age and gender did not have a significant effect on any components of the DAS28. C-reactive protein (CRP) and DAS28(CRP) were not influenced by age. CONCLUSIONS: A high DAS28 was found to perform equally in all age groups, in men and women, despite the elevating effect of age on ESR. In elderly men with low disease activity, remission rate could be underestimated by an elevated ESR. The present case-control study was conducted to investigate the relationship between smoking and rheumatoid arthritis, and to investigate formally the interaction between sex, smoking, and risk for developing rheumatoid arthritis. The study was performed in the Central District of Finland. Cases were patients with rheumatoid arthritis and the control group was a random sample of the general population. Logistic regression models were used to evaluate the effect of smoking on risk for rheumatoid arthritis, after adjusting for the effects of age, education, body mass index, and indices of general health and pain. Overall, 1095 patients with rheumatoid arthritis and 1530 control individuals were included. Patients were older, less well educated, more disabled, and had poorer levels of general health as compared with control individuals (all P < 0.01). Preliminary analyses revealed the presence of substantial statistical interaction between smoking and sex (P < 0.001). In separate multivariable analyses, past history of smoking was associated with increased risk for rheumatoid arthritis overall in men (odds ratio 2.0, 95% confidence interval 1.2-3.2) but not in women. Among men, this effect was seen only for rheumatoid factor-positive rheumatoid arthritis. There were significant interactions between smoking and age among women but not among men. We conclude that sex is a biologic effect modifier in the association between smoking and rheumatoid arthritis. The role of menopause in the etiology of rheumatoid arthritis merits further research. OBJECTIVE: To determine whether the Simplified Disease Activity Index (SDAI) and the Clinical Disease Activity Index (CDAI) are equally applicable for the total population with rheumatoid arthritis (RA). METHODS: Five hundred and fifty-seven outpatients with RA [432 females, 125 males; median age 64 years (range 18-85); median disease duration 48 months (range 2-548)] were enrolled consecutively in this cross-sectional study. SDAI, CDAI, patient's assessment of pain on the visual analogue scale (VAS) 0-100, rheumatoid factor (RF), and disease duration were recorded. Linear regression analysis was performed for each confounding factor. RESULTS: The median SDAI for all 557 patients was 11.6 (range 0.07-46.60) and the median CDAI was 10.7 (0.00-42.10). The median SDAI was 12.2 (0.07-46.60) in females and 8.0 (0.10-35.20) in males. The respective medians for the CDAI were 11.3 (0.00-42.10) and 7.1 (0.00-32.00). These differences were highly statistically significant (p<0.001). Patient's assessment of pain on the VAS 0-100 scale had a median value of 32 mm. Regression analysis revealed a highly significant relationship between SDAI/CDAI levels and patient's pain rating (SDAI: r = 0.660, p<0.001; CDAI: r = 0.671, p<0.001). On multiple regression analysis, pain exerted a highly significant influence on SDAI and CDAI levels (p<0.001), whereas age, disease duration, and RF were not correlated with either level. CONCLUSION: SDAI and CDAI values are highly dependent on the patient's pain perception and gender. The effects of patient's age, disease duration, and RF were inconclusive with respect to the values of the respective disease activity indexes. OBJECTIVE: To assess gender differences in disease characteristics and treatment responses over time in a disease-modifying antirheumatic drug (DMARD)-naive seropositive early rheumatoid arthritis (RA) cohort. METHODS: Patients with polyarticular disease who were DMARD-naive and had seropositive early RA (< 14 months) were recruited by the Western Consortium of Practicing Rheumatologists. Each patient was examined at study entry, after 6 and 12 months, and yearly thereafter. Clinical and demographic data were collected. We investigated gender differences in baseline disease characteristics and treatment using chi-squared, Mann-Whitney U, and t tests. We used generalized estimating equations (GEE) models for repeated measures to examine whether the rate of change of specific disease outcomes during the first 2 years after DMARD initiation was significantly influenced by gender. RESULTS: At baseline, men (n = 67) and women (n = 225) had similar disease activity and radiographic damage; men, however, had significantly worse erosion, while women had worse joint space narrowing. Despite similar treatment, women had worse disease progression over the 2-year followup, as assessed by trends in Disease Activity Score 28/erythrocyte sedimentation rate (DAS28-ESR4), physician global scores, and tender joint counts. In the GEE model, gender was significantly associated with the rate of change of DAS28-ESR4 scores (p = 0.009), although not independently associated with disease activity. Self-reported measures (Health Assessment Questionnaire-Disability Index, patient global scores, fatigue, pain) were worse among women at baseline and throughout the study period. Men were more likely to achieve remission. CONCLUSION: At baseline, men and women had similar disease activity and joint damage. Responses to treatment over time were better among men in this prebiologic era; women had worse progression despite similar treatment. |
370 | What is FINDbase? | Frequency of INherited Disorders database (FINDbase) (http://www.findbase.org) is a relational database, derived from the ETHNOS software, recording frequencies of causative mutations leading to inherited disorders worldwide. Database records include the population and ethnic group, the disorder name and the related gene, accompanied by links to any corresponding locus-specific mutation database, to the respective Online Mendelian Inheritance in Man entries and the mutation together with its frequency in that population. The initial information is derived from the published literature, locus-specific databases and genetic disease consortia. FINDbase offers a user-friendly query interface, providing instant access to the list and frequencies of the different mutations. Query outputs can be either in a table or graphical format, accompanied by reference(s) on the data source. Registered users from three different groups, namely administrator, national coordinator and curator, are responsible for database curation and/or data entry/correction online via a password-protected interface. Database access is free of charge and there are no registration requirements for data querying. FINDbase provides a simple, web-based system for population-based mutation data collection and retrieval and can serve not only as a valuable online tool for molecular genetic testing of inherited disorders but also as a non-profit model for sustainable database funding, in the form of a 'database-journal'. | [24234438, 21113021, 22659238, 17135191] | 477 | Frequency of INherited Disorders database (FIND base; http://www.findbase.org) records frequencies of causative genetic variations worldwide. Database records include the population and ethnic group or geographical region, the disorder name and the related gene, accompanied by links to any related external resources and the genetic variation together with its frequency in that population. In addition to the regular data content updates, we report the following significant advances: (i) the systematic collection and thorough documentation of population/ethnic group-specific pharmacogenomic markers allele frequencies for 144 markers in 14 genes of pharmacogenomic interest from different classes of drug-metabolizing enzymes and transporters, representing 150 populations and ethnic groups worldwide; (ii) the development of new data querying and visualization tools in the expanded FINDbase data collection, built around Microsoft's PivotViewer software (http://www.getpivot.com), based on Microsoft Silverlight technology (http://www.silverlight.net) that facilitates querying of large data sets and visualizing the results; and (iii) the establishment of the first database journal, by affiliating FINDbase with Human Genomics and Proteomics, a new open-access scientific journal, which would serve as a prime example of a non-profit model for sustainable database funding. |
371 | Can vitamin B1 deficiency cause encephalopathy? | Wernicke's encephalopathy (WE) is a severe neurological syndrome caused by thiamine (vitamin B1) deficiency and clinically characterized by the sudden onset of mental status changes, ocular abnormalities, and ataxia. It is commonly associated with heavy alcohol consumption. Other clinical associations are with hyperemesis gravidarum (HG), starvation, and prolonged intravenous feeding. | [22703872, 11304071, 20943242, 24701066, 24620429, 23042832, 24117525, 23935638, 23715222, 25515801, 9279523, 21217196, 25276464, 23278769, 24973622, 7695937, 16254404, 24379094, 14644703, 2361826, 25050351, 23090806] | 478 | INTRODUCTION: Wernicke's encephalopathy caused by thiamine deficiency is typically characterised by a mental-status change, oculomotor dysfunction and an ataxia. Pellagra is the clinical presentation of niacin deficiency comprising cutaneous, gastrointestinal and neuropsychiatric manifestations. OBSERVATION: We report a case of encephalopathy due to dual vitamin deficiency of both thiamine (vitamin B1) and niacin (vitamin PP) in an 80-year-old women, hospitalized for severe sepsis caused by aspiration pneumonia. Severe malnutrition and alcohol consumption pointed to a diagnosis of vitamin deficiency. The clinical presentation and magnetic resonance imaging (MRI) were compatible with Wernicke's encephalopathy that remained irreversible despite vitamin B1 supplementation. Niacin supplementation allowed for complete regression of the observed symptoms compatible with niacin deficiency. CONCLUSION: Malnourished and alcoholic patients showing signs of encephalopathy should receive supplemental multivitamins including niacin. The classic signs of vitamin deficiency only occur in states of extreme depletion and are unreliable indicators for early treatment or prophylaxis of alcoholic patients at risk. Post-mortem findings demonstrate that thiamine (vitamin B1) deficiency sufficient to cause irreversible brain damage is not diagnosed ante mortem in 80-90% of these patients. The causes of vitamin deficiency are reviewed with special attention to the inhibition of oral thiamine hydrochloride absorption in man caused by malnutrition present in alcoholic patients or by the direct effects of ethanol on intestinal transport. As the condition of the patient misusing alcohol progresses, damage to brain, liver, gastrointestinal tract, and pancreas continue (with other factors discussed) to further compromise the patient. Decreased intake, malabsorption, reduced storage, and impaired utilization further reduce the chances of unaided recovery. Failure of large oral doses of thiamine hydrochloride to provide an effective treatment for Wernicke's encephalopathy emphasizes the need for adequate and rapid replacement of depleted brain thiamine levels by repeated parenteral therapy in adequate doses. Wernicke's encephalopathy (WE) is a potentially reversible yet serious neurological manifestation caused by vitamin B1(thiamine) deficiency. It is commonly associated with heavy alcohol consumption. Other clinical associations are with hyperemesis gravidarum (HG), starvation, and prolonged intravenous feeding. Most patients present with the triad of ocular signs, ataxia, and confusion. It can be associated with life-threatening complication like central pontine myelinolysis (CPM). We report two cases of WE following HG, with two different outcomes. BACKGROUND: Wernicke's encephalopathy-Korsakoff syndrome (WE-KS) is common in alcoholics, caused by thiamine deficiency (TD; vitamin B1) and associated with lesions to the thalamus (THAL). Although TD alone can cause WE, the high incidence in alcoholism suggests that TD and ethanol (EtOH) interact. METHODS: Mice in control, TD, or EtOH groups alone or combined were studied after 5 or 10 days of treatment. THAL and entorhinal cortex (ENT) histochemistry and mRNA were assessed. RESULTS: Combined EtOH-TD treatment for 5 days (EtOH-TD5) showed activated microglia, proinflammatory gene induction and THAL neurodegeneration that was greater than that found with TD alone (TD5), whereas 10 days resulted in marked THAL degeneration and microglial-neuroimmune activation in both groups. In contrast, 10 days of TD did not cause ENT degeneration. Interestingly, in ENT, TD10 activated microglia and astrocytes more than EtOH-TD10. In THAL, multiple astrocytic markers were lost consistent with glial cell loss. TD blocks glucose metabolism more than acetate. Acetate derived from hepatic EtOH metabolism is transported by monocarboxylic acid transporters (MCT) into both neurons and astrocytes that use acetyl-CoA synthetase (AcCoAS) to generate cellular energy from acetate. MCT and AcCoAS expression in THAL is lower than ENT prompting the hypothesis that focal THAL degeneration is related to insufficient MCT and AcCoAS in THAL. To test this hypothesis, we administered glycerin triacetate (GTA) to increase blood acetate and found it protected the THAL from TD-induced degeneration. CONCLUSIONS: Our findings suggest that EtOH potentiates TD-induced THAL degeneration through neuroimmune gene induction. The findings support the hypothesis that TD deficiency inhibits global glucose metabolism and that a reduced ability to process acetate for cellular energy results in THAL focal degeneration in alcoholics contributing to the high incidence of Wernicke-Korsakoff syndrome in alcoholism. Introduction. Wernicke's encephalopathy is a well-described syndrome characterized by the classic triad of confusion, ataxia, and ophthalmoplegia. Wernicke's encephalopathy results from thiamine (vitamin B1) deficiency. Common causes include alcoholism and gastric disorders. Wernicke's has been described in patients with acquired immune deficiency syndrome (AIDS); however, given these patients' immunosuppressed state, the diagnosis of Wernicke's encephalopathy is not apparent. Case Presentation. A 31-year-old previously healthy male presented to the ER complaining of progressive dyspnea. Workup revealed HIV/AIDS and PCP pneumonia. He was treated and improved. On day 14 he became confused and developed nystagmus and ataxia. Considering his immunocompromised state, infectious and neoplastic etiologies topped the differential diagnosis. CT head was negative. Lumbar puncture was unremarkable. Brain MRI revealed increased T2 signal in the medial thalamus bilaterally. Intravenous thiamine was administered resulting in resolution of symptoms. Discussion. The classic triad of Wernicke's encephalopathy occurs in 10% of cases. When immunosuppressed patients develop acute neurologic symptoms infectious or neoplastic etiologies must be excluded. However, given the relative safety of thiamine supplementation, there should be a low threshold for initiating therapy in order to reverse the symptoms and prevent progression to Korsakoff dementia, which is permanent. BACKGROUND: Wernicke encephalopathy is caused by thiamine (vitamin B1) deficiency. It is generally considered to be a disease of adult alcoholics. However, it is known to occur in the pediatric population and in non-alcoholic conditions. DATA SOURCES: We searched PubMed with the key words Wernicke, thiamine, pediatric, children and adolescents and selected publications that were deemed appropriate. RESULTS: The global prevalence rates of hunger, poverty and resultant nutrient deprivation have decreased in the 21st century. However, several scenarios which may predispose to Wernicke encephalopathy may be increasingly prevalent in children and adolescents such as malignancies, intensive care unit stays and surgical procedures for the treatment of obesity. Other predisposing conditions include magnesium deficiency and defects in the SLC19A3 gene causing thiamine transporter-2 deficiency. The classic triad consists of encephalopathy, oculomotor dysfunction and gait ataxia but is not seen in a majority of patients. Treatment should be instituted immediately when the diagnosis is suspected clinically without waiting for laboratory confirmation. Common magnetic resonance findings include symmetric T2 hyperintensities in dorsal medial thalamus, mammillary bodies, periaqueductal gray matter, and tectal plate. CONCLUSIONS: Wernicke encephalopathy is a medical emergency. Delay in its recognition and treatment may lead to significant morbidity, irreversible neurological damage or even death. This article aims to raise the awareness of this condition among pediatricians. BACKGROUND: Thiamine deficiency in patients who abuse alcohol can cause Wernicke's encephalopathy (WE). Thiamine supplements are given to prevent this complication. Guidelines exist for giving thiamine supplementation in the inpatient population. However, similar guidelines are not available for clinicians detoxifying patients in the community, and consequently, assessment of risk of WE and prophylaxis can be inconsistent. METHODS: A scoring system to assess risk of WE was developed and evaluated by comparing practice before and after introduction of the system. One hundred and twenty-six cases requiring alcohol detoxification were examined: 94 before introduction of the scoring system and 32 afterward. RESULTS: Before introduction of the scoring system, a risk assessment for developing WE was performed in 30% of patients and parenteral thiamine prescribed in 32%. After introduction of the scoring system, risk assessment and administration of parenteral thiamine increased to 100 and 75%, respectively. There was 1 probable case of WE before introduction of the scoring system and none afterward. CONCLUSIONS: We conclude that assessment of WE is often inadequate, leading to inadequate thiamine administration. The new scoring system allows simple, structured risk assessment for WE and thus guides appropriate thiamine administration. This is of most value to clinicians treating the consequences of alcohol dependence in the community. Thiamine (vitamin B1) deficiency, associated with a variety of conditions, including chronic alcoholism and bariatric surgery for morbid obesity, can result in the neurological disorder Wernicke's encephalopathy (WE). Recent work building upon early observations in animal models of thiamine deficiency has demonstrated an inflammatory component to the neuropathology observed in thiamine deficiency. The present, multilevel study including in vivo magnetic resonance imaging (MRI) and spectroscopy (MRS) and postmortem quantification of chemokine and cytokine proteins sought to determine whether a combination of these in vivo neuroimaging tools could be used to characterize an in vivo MR signature for neuroinflammation. Thiamine deficiency for 12days was used to model neuroinflammation; glucose loading in thiamine deficiency was used to accelerate neurodegeneration. Among 38 animals with regional brain tissue assayed postmortem for cytokine/chemokine protein levels, three groups of rats (controls+glucose, n=6; pyrithiamine+saline, n=5; pyrithiamine+glucose, n=13) underwent MRI/MRS at baseline (time 1), after 12days of treatment (time 2), and 3h after challenge (glucose or saline, time 3). In the thalamus of glucose-challenged, thiamine deficient animals, correlations between in vivo measures of pathology (lower levels of N-acetyle aspartate and higher levels of lactate) and postmortem levels of monocyte chemotactic protein-1 (MCP-1, also known as chemokine ligand 2, CCL2) support a role for this chemokine in thiamine deficiency-related neurodegeneration, but do not provide a unique in vivo signature for neuroinflammation. Acute Wernicke's encephalopathy (WE) is caused by profound vitamin B1 (thiamine) deficiency and commonly presents with the classic clinical triad of mental confusion, ataxia, and ophthalmoplegia. This characteristic presentation results from the propensity of acute thiamine deficiency to preferentially injure specific brain regions: the dorsomedial thalamus, periaqueductal gray, and mamillary bodies. In these regions, abnormal magnetic resonance signaling on conventional sequences has been well described; however, diffusion restriction has only recently been reported. The authors demonstrate diffusion-weighted imaging (DWI) abnormalities of the splenium of the corpus callosum in a patient with acute WE, which has not been reported previously, and suggest a potential pathological mechanism. With the recent addition of DWI, MRI is becoming more sensitive to the changes in acute WE. Furthermore, the use of apparent diffusion coefficient mapping to evaluate the extent of likely underlying cytotoxic injury may help determine long-term response to vitamin therapy and, thus, disability. Wernicke's encephalopathy is a serious neurological manifestation of vitamin B1 deficiency. We report a case occurring secondary to hyperemesis gravidarum. Wernicke's encephalopathy (WE) is a severe neurological syndrome caused by thiamine (vitamin B1) deficiency and clinically characterized by the sudden onset of mental status changes, ocular abnormalities, and ataxia. Apart from chronic alcoholism, the most common cause of WE, a lot of other conditions causing malnutrition and decreasing thiamine absorption such as gastrointestinal surgical procedures and hyperemesis gravidarum must be considered as predisposing factors. Due to its low prevalence and clinical heterogeneity, WE is often misdiagnosed, leading to persistent dysfunctions and, in some cases, to death. Nowadays, MR imaging of the brain, showing T2 and FLAIR hyperintensities in typical (thalami, mammillary bodies, tectal plate, and periaqueductal area) and atypical areas (cerebellum, cranial nerve nuclei, and cerebral cortex), is surely the most important and effective tool in the diagnostic assessment of WE. The aim of this paper is to propose a state of the art of the role of MR imaging in the early diagnosis of this complex disease. Wernicke's encephalopathy is a neurological disorder caused by thiamine (vitamin B1) deficiency characterized by vertigo, ataxia, and mental confusion. Wernicke's encephalopathy has a causative association with alcoholism but recently there has been an increased prevalence also in other clinical conditions. In literature potentially fatal Wernicke's encephalopathy onset in an advanced achalasia has been previously reported only once. We describe for the first time an improvement of achalasic symptoms in a young patient affected by end-stage achalasia and anorexia nervosa (coming from ineffective Heller-Dor myotomy) after vitamin B1 supplementation. This case report suggest a potential positive impact of B1 supplementation on end-stage achalasic patients and requires systematic studies to confirm this observation. |
372 | Which methyl-CpG-binding protein when mutant becomes the hallmark for Rett syndrome? | Rett syndrome (RTT) was shown to be caused by mutations in the methyl-CpG-binding protein 2 (MECP2) gene, with molecular studies identifying MECP2 mutations in up to 80% of classic RTT patients. MECP2 protein was found to assist in the transcriptional silencing process via DNA methylation. We therefore hypothesize that disruption of this gene alters the normal developmental expression of various other genes, some of which must account for the peculiar neurologic phenotype of RTT. | [22138506, 22302819, 18534925, 11180222] | 479 | Rett syndrome (RTT) results from loss-of-function mutations in the gene encoding the methyl-CpG-binding protein 2 (MeCP2) and is characterized by abnormal motor, respiratory and autonomic control, cognitive impairment, autistic-like behaviors and increased risk of seizures. RTT patients and Mecp2-null mice exhibit reduced expression of brain-derived neurotrophic factor (BDNF), which has been linked in mice to increased respiratory frequency, a hallmark of RTT. The present study was undertaken to test the hypotheses that BDNF deficits in Mecp2 mutants are associated with reduced activation of the BDNF receptor, TrkB, and that pharmacologic activation of TrkB would improve respiratory function. We characterized BDNF protein expression, TrkB activation and respiration in heterozygous female Mecp2 mutant mice (Het), a model that recapitulates the somatic mosaicism for mutant MECP2 found in typical RTT patients, and evaluated the ability of a small molecule TrkB agonist, LM22A-4, to ameliorate biochemical and functional abnormalities in these animals. We found that Het mice exhibit (1) reduced BDNF expression and TrkB activation in the medulla and pons and (2) breathing dysfunction, characterized by increased frequency due to periods of tachypnea, and increased apneas, as in RTT patients. Treatment of Het mice with LM22A-4 for 4 weeks rescued wild-type levels of TrkB phosphorylation in the medulla and pons and restored wild-type breathing frequency. These data provide new insight into the role of BDNF signaling deficits in the pathophysiology of RTT and highlight TrkB as a possible therapeutic target in this disease. Severely arrhythmic breathing is a hallmark of Rett syndrome (RTT) and profoundly affects quality of life for patients and their families. The last decade has seen the identification of the disease-causing gene, methyl-CpG-binding protein 2 (Mecp2) and the development of mouse models that phenocopy many aspects of the human syndrome, including breathing dysfunction. Recent studies have begun to characterize the breathing phenotype of Mecp2 mutant mice and to define underlying electrophysiological and neurochemical deficits. The picture that is emerging is one of defects in synaptic transmission throughout the brainstem respiratory network associated with abnormal expression in several neurochemical signaling systems, including brain-derived neurotrophic factor (BDNF), biogenic amines and gamma-amino-butyric acid (GABA). Based on such findings, potential therapeutic strategies aimed at improving breathing by targeting deficits in neurochemical signaling are being explored. This review details our current understanding of respiratory dysfunction and underlying mechanisms in RTT with a particular focus on insights gained from mouse models. Rett syndrome (RTT) is an X-linked dominant neurodevelopmental disorder that manifests in females, typically after the first year of life. It is a leading cause of mental retardation and autistic behavior in girls and women; a hallmark of the disease is incessant hand movements in the form of wringing, twisting, or clapping. It was recently discovered that RTT is caused by mutations in the methyl-CpG-binding protein 2 (MECP2) gene. MECP2 assists in the transcriptional silencing process via DNA methylation; we hypothesize that disruption of this gene alters the normal developmental expression of various other genes, some of which must account for the peculiar neurologic phenotype of RTT. Molecular studies have identified MECP2 mutations in up to 80% of classic RTT patients; mutation type has some effect on the phenotypic manifestation of RTT, but the pattern of X inactivation seems to determine phenotypic severity. Favorable (skewed) X inactivation can so spare a patient from the effects of mutant MECP2 that they display only the mildest learning disability or no phenotype at all. The unmitigated impact of mutant MECP2 can be inferred from the few males who have been born into RTT kindreds with such severe neonatal encephalopathy that they did not survive their second year. MECP2 mutations thus manifest in a far broader array of phenotypes than classic RTT. This discovery should prove helpful in diagnosing cases of mild learning disability or severe neonatal encephalopathies of unknown cause and also should provide insight into the pathogenesis of RTT. |
373 | Are epigenetic modifications implicated in cardiovascular development and disease? | Genetic and epigenetic factors are of great importance in cardiovascular biology and disease. Aberrant epigenetic mechanisms may lead to pathological consequences such as cardiovascular disease (CAD).Recent studies have greatly expanded our understanding of the regulation of cardiovascular development at the chromatin level, including the remodeling of chromatin and the modification of histones. Thus, understanding chromatin-level regulation will allow for a better appreciation of gene regulation as a whole and may set a fundamental basis for cardiovascular disease. | [21372004, 23261320, 23640490, 22773406, 19488075, 22234702, 20881938, 22621747, 22981780, 22035349, 21764886, 22669047, 24183004, 23448446, 20603647] | 480 | Epigenetic control mechanisms play a key role in the regulation of embryonic development and tissue homeostasis and modulate cardiovascular diseases. Increasing evidence suggests that lineage commitment of stem/progenitor cells is tightly regulated by epigenetic mechanisms. These epigenetic control mechanisms include DNA and histone modifications, which modulate the chromatin structure thereby regulating access of transcription factors. Particularly, the modification of histone acetylation and methylation, which is controlled by families of histone acetylases/deacetylases and methyltransferases/demethylases, respectively, controls stem cell maintenance, differentiation, and function. This review article summarizes our current understanding of epigenetic mechanisms regulating the differentiation of cardiovascular cells, specifically endothelial cells and cardiac muscle lineages. In particular, the article will focus on the enzymes which modify histones and are involved in chromatin remodelling. A commonly-assumed paradigm holds that the primary genetic determinant of cardiovascular disease resides within the DNA sequence of our genes. This paradigm can be challenged. For example, how do sequence changes in the non-coding region of the genome influence phenotype? Why are all diseases not shared between identical twins? Part of the answer lies in the fact that the environment or exogenous stimuli clearly influence disease susceptibility, but it was unclear in the past how these effects were signalled to the static DNA code. Epigenetics is providing a newer perspective on these issues. Epigenetics refers to chromatin-based mechanisms important in the regulation of gene expression that do not involve changes to the DNA sequence per se. The field can be broadly categorized into three areas: DNA base modifications (including cytosine methylation and cytosine hydroxymethylation), post-translational modifications of histone proteins, and RNA-based mechanisms that operate in the nucleus. Cardiovascular disease pathways are now being approached from the epigenetic perspective, including those associated with atherosclerosis, angiogenesis, ischemia-reperfusion damage, and the cardiovascular response to hypoxia and shear stress, among many others. With increasing interest and expanding partnerships in the field, we can expect new insights to emerge from epigenetic perspectives of cardiovascular health. This paper reviews the principles governing epigenetic regulation, discusses their presently-understood importance in cardiovascular disease, and considers the growing significance we are likely to attribute to epigenetic contributions in the future, as they provide new mechanistic insights and a host of novel clinical applications. Genetic and epigenetic factors are of great importance in cardiovascular biology and disease. Tobacco-smoking, one of the most important cardiovascular risk factors, is itself partially determined by genetic background and is associated with altered epigenetic patterns. This could render the genetics and epigenetics of smoking-related cardiovascular disease a textbook example of environmental epigenetics and modern approaches to multimodal data analysis. A pronounced association of smoking-related methylation patterns in the F2RL3 gene with prognosis in patients with stable coronary heart disease has recently been described. Nonetheless, surprisingly little concrete knowledge on the role of specific genetic variants and epigenetic modifications in the development of cardiovascular diseases in people who smoke has been accumulated. Beyond the current knowledge, the present review briefly outlines some chief challenges and priorities for moving forward in this field. Cellular commitment to a specific lineage is controlled by differential silencing of genes, which in turn depends on epigenetic processes such as DNA methylation and histone modification. During early embryogenesis, the mammalian genome is 'wiped clean' of most epigenetic modifications, which are progressively re-established during embryonic development. Thus, the epigenome of each mature cellular lineage carries the record of its developmental history. The subsequent trajectory and pattern of development are also responsive to environmental influences, and such plasticity is likely to have an epigenetic basis. Epigenetic marks may be transmitted across generations, either directly by persisting through meiosis or indirectly through replication in the next generation of the conditions in which the epigenetic change occurred. Developmental plasticity evolved to match an organism to its environment, and a mismatch between the phenotypic outcome of adaptive plasticity and the current environment increases the risk of metabolic and cardiovascular disease. These considerations point to epigenetic processes as a key mechanism that underpins the developmental origins of chronic noncommunicable disease. Here, we review the evidence that environmental influences during mammalian development lead to stable changes in the epigenome that alter the individual's susceptibility to chronic metabolic and cardiovascular disease, and discuss the clinical implications. Epigenetics represents a phenomenon of altered heritable phenotypic expression of genetic information occurring without changes in DNA sequence. Epigenetic modifications control embryonic development, differentiation and stem cell (re)programming. These modifications can be affected by exogenous stimuli (e.g., diabetic milieu, smoking) and oftentimes culminate in disease initiation. DNA methylation has been studied extensively and represents a well-understood epigenetic mechanism. During this process cytosine residues preceding a guanosine in the DNA sequence are methylated. CpG-islands are short-interspersed DNA sequences with clusters of CG sequences. The abnormal methylation of CpG islands in the promoter region of genes leads to a silencing of genetic information and finally to alteration of biological function. Emerging data suggest that these epigenetic modifications also impact on the development of cardiovascular disease. Histone modifications lead to the modulation of the expression of genetic information through modification of DNA accessibility. In addition, RNA-based mechanisms (e.g., microRNAs and long non-coding RNAs) influence the development of disease. We here outline the recent work pertaining to epigenetic changes in a cardiovascular disease setting. Epigenetics refers to a heritable change in the pattern of gene expression that is mediated by a mechanism specifically not due to alterations in the primary nucleotide sequence. Well-known epigenetic mechanisms encompass DNA methylation, chromatin remodeling (histone modifications), and RNA interference. Functionally, epigenetics provides an extra layer of transcriptional control and plays a crucial role in normal physiological development, as well as in pathological conditions. Aberrant DNA methylation is implicated in immune dysfunction, inflammation, and insulin resistance. Epigenetic changes may be responsible for 'metabolic memory' and development of micro- and macrovascular complications of diabetes. MicroRNAs are critical in the maintenance of glomerular homeostasis and hence RNA interference may be important in the progression of renal disease. Recent studies have shown that epigenetic modifications orchestrate the epithelial-mesenchymal transition and eventually fibrosis of the renal tissue. Oxidative stress, inflammation, hyperhomocysteinemia, and uremic toxins could induce epimutations in chronic kidney disease. Epigenetic alterations are associated with inflammation and cardiovascular disease in patients with chronic kidney disease. Reversible nature of the epigenetic changes gives a unique opportunity to halt or even reverse the disease process through targeted therapeutic strategies. Consolidated knowledge is accumulating as to the role of epigenetic regulatory mechanisms in the physiology of vascular development and vascular tone as well as in the pathogenesis of cardiovascular disease. The modulation of gene expression through modification of the epigenome by structural changes of the chromatin architecture without alterations of the associated genomic DNA sequence is part of the cellular response to environmental changes. Such environmental conditions, which are finally being translated into adaptations of the cardiovascular system, also comprise pathological conditions such as atherosclerosis or myocardial infarction. This review summarizes recent findings on the epigenetics of vascular regulation and disease and presents nutritional and pharmacological approaches as novel epigenetic strategies in the prevention and treatment of cardiovascular disease. Epigenetic phenomena are defined as heritable mechanisms that establish and maintain mitotically stable patterns of gene expression without modifying the base sequence of DNA. The major epigenetic features of mammalian cells include DNA methylation, post-translational histone modifications and RNA-based mechanisms including those controlled by small non-coding RNAs (miRNAs). The impact of epigenetic mechanisms in cardiovascular pathophysiology is now emerging as a major player in the interface between genotype to phenotype variability. This topic of research has strict implications on disease development and progression, and opens up possible novel preventive strategies in cardiovascular disease. An important aspect of epigenetic mechanisms is that they are potentially reversible and may be influenced by nutritional-environmental factors and through gene-environment interactions, all of which have an important role in complex, multifactorial diseases such as those affecting the cardiovascular system. Gene expression regulation through the interplay of DNA methylation and histone modifications is well-established, although the knowledge about the function of epigenetic signatures in cardiovascular disease is still largely unexplored. The study of epigenetic markers is, therefore, a very promising frontier of science which may aid in a deeper understanding of molecular mechanisms underlying the modulation of gene expression in the biomolecule pathways linked to cardiovascular diseases. This review focuses on up-to-date knowledge pertaining to the role of epigenetics, from DNA methylation to miRNAs, in major cardiovascular diseases such as ischemic heart disease, hypertension, heart failure and stroke. The cardiovascular system is broadly composed of the heart, which pumps blood, and the blood vessels, which carry blood to and from tissues of the body. Heart malformations are the most serious common birth defect, affecting at least 2% of newborns and leading to significant morbidity and mortality. Severe heart malformations cause heart failure in fetuses, infants, and children, whereas milder heart defects may not trigger significant heart dysfunction until early or midadulthood. Severe vasculogenesis or angiogenesis defects in embryos are incompatible with life, and anomalous arterial patterning may cause vascular aberrancies that often require surgical treatment. It is therefore important to understand the underlying mechanisms that control cardiovascular development. Understanding developmental mechanisms will also help us design better strategies to regenerate cardiovascular tissues for therapeutic purposes. An important mechanism regulating genes involves the modification of chromatin, the higher-order structure in which DNA is packaged. Recent studies have greatly expanded our understanding of the regulation of cardiovascular development at the chromatin level, including the remodeling of chromatin and the modification of histones. Chromatin-level regulation integrates multiple inputs and coordinates broad gene expression programs. Thus, understanding chromatin-level regulation will allow for a better appreciation of gene regulation as a whole and may set a fundamental basis for cardiovascular disease. This review focuses on how chromatin-remodeling and histone-modifying factors regulate gene expression to control cardiovascular development. Several studies indicate that impaired foetal growth, and in utero exposure to risk factors, especially maternal hypercholesterolaemia, may be relevant for the early onset of cardiovascular damage. The exact molecular mechanisms of such foetal programming are still unclear. Epigenetics may represent one of the possible scientific explanations of the impact of such intrauterine risk factors for the subsequent development of cardiovascular disease (CVD) during adulthood. Translational studies support this hypothesis; however, a direct causality in humans has not been ascertained. This hypothesis could be investigated in primates and in human post-mortem foetal arteries. Importantly, some studies also suggest the transgenerational transmission of epigenetic risk. The recently launched International Human Epigenome Consortium and the NIH Roadmap Epigenomics Mapping Consortium will provide the rationale for a useful clinical scenario for primary prevention and therapy of CVD. Despite the heritable nature of epigenetic modification, the clinically relevant information shows that it could be reversible through therapeutic approaches, including histone deacetylase inhibitors, histone acetyltransferase inhibitors, and commonly used drugs such as statins. Our understanding of congenital heart defects has been recently advanced by whole exome sequencing projects, which have identified de novo mutations in many genes encoding epigenetic regulators. Notably, multiple subunits of switching defective/sucrose non-fermenting (SWI/SNF) chromatin-remodeling complexes have been identified as strong candidates underlying these defects because they physically and functionally interact with cardiogenic transcription factors critical to cardiac development, such as TBX5, GATA-4, and NKX2-5. While these studies indicate a critical role of SWI/SNF complexes in cardiac development and congenital heart disease, many exciting new discoveries have identified their critical role in the adult heart in both physiological and pathological conditions involving multiple cell types in the heart, including cardiomyocytes, vascular endothelial cells, pericytes, and neural crest cells. This review summarizes the role of SWI/SNF chromatin-remodeling complexes in cardiac development, congenital heart disease, cardiac hypertrophy, and vascular endothelial cell survival. Although the clinical relevance of SWI/SNF mutations has traditionally been focused primarily on their role in tumor suppression, these recent studies illustrate their critical role in the heart whereby they regulate cell proliferation, differentiation, and apoptosis of cardiac derived cell lines. Despite advances in the prevention and management of cardiovascular disease (CVD), this group of multifactorial disorders remains a leading cause of mortality worldwide. CVD is associated with multiple genetic and modifiable risk factors; however, known environmental and genetic influences can only explain a small part of the variability in CVD risk, which is a major obstacle for its prevention and treatment. A more thorough understanding of the factors that contribute to CVD is, therefore, needed to develop more efficacious and cost-effective therapy. Application of the 'omics' technologies will hopefully make these advances a reality. Epigenomics has emerged as one of the most promising areas that will address some of the gaps in our current knowledge of the interaction between nature and nurture in the development of CVD. Epigenetic mechanisms include DNA methylation, histone modification, and microRNA alterations, which collectively enable the cell to respond quickly to environmental changes. A number of CVD risk factors, such as nutrition, smoking, pollution, stress, and the circadian rhythm, have been associated with modification of epigenetic marks. Further examination of these mechanisms may lead to earlier prevention and novel therapy for CVD. |
374 | Which deiodinases are present in skeletal muscle? | Type 2 and Type 3 deiodinases are expressed in skeletal muscle and their expression is modulated by disease state and fasting. | [16127464, 19293265, 23396445, 17986277] | 481 | The relative roles of the types 1 and 2 iodothyronine deiodinases (D1 and D2) in extrathyroidal 3,5,3'-triiodothyronine (T3) production in humans are unknown. We calculated the rate of thyroxine (T4) to T3 conversion by intact cells transiently expressing D1 or D2 at low (2 pM), normal (20 pM), and high (200 pM) free T4 concentrations. Deiodinase activities were then assayed in cell sonicates. The ratio of T3 production in cell sonicates (catalytic efficiency) was multiplied by the tissue activities reported in human liver (D1) and skeletal muscle (D2). From these calculations, we predict that in euthyroid humans, D2-generated T3 is 29 nmol/d, while that of D1-generated T3 is 15 nmol/d, from these major deiodinase-expressing tissues. The total estimated extrathyroidal T3 production, 44 nmol/d, is in close agreement with the 40 nmol T3/d based on previous kinetic studies. D2-generated T3 production accounts for approximately 71% of the peripheral T3 production in hypothyroidism, but D1 for approximately 67% in thyrotoxic patients. We also show that the intracellular D2-generated T3 has a greater effect on T3-dependent gene transcription than that from D1, which indicates that generation of nuclear T3 is an intrinsic property of the D2 protein. We suggest that impairment of D2-generated T3 is the major cause of the reduced T3 production in the euthyroid sick syndrome. CONTEXT: The iodothyronine deiodinases D1, D2, and D3 enable tissue-specific adaptation of thyroid hormone levels in response to various conditions, such as hypothyroidism or fasting. The possible expression of D2 mRNA in skeletal muscle is intriguing because this enzyme could play a role in systemic as well as local T3 production. OBJECTIVE: We determined D2 activity and D2 mRNA expression in human skeletal muscle biopsies under control conditions and during hypothyroidism, fasting, and hyperinsulinemia. DESIGN: This was a prospective study. SETTING: The study was conducted at a university hospital. PATIENTS: We studied 11 thyroidectomized patients with differentiated thyroid carcinoma (DTC) on and after 4 wk off T4( replacement and six healthy lean subjects in the fasting state and during hyperinsulinemia after both 14 and 62 h of fasting. MEAN OUTCOME MEASURES: D2 activity and D2 mRNA levels were measured in skeletal muscle samples. RESULTS: No differences were observed in muscle D2 mRNA levels in DTC patients on and off T4 replacement therapy. In healthy subjects, muscle D2 mRNA levels were lower after 62 h compared to 14 h of fasting. Insulin increased mRNA expression after 62 h, but not after 14 h of fasting. Skeletal muscle D2 activities were very low and not influenced by hypothyroidism and fasting. CONCLUSION: Human skeletal muscle D2 mRNA expression is modulated by fasting and insulin, but not by hypothyroidism. The lack of a clear effect of D2 mRNA modulation on the observed low D2 activities questions the physiological relevance of D2 activity in human skeletal muscle. The proliferation and differentiation of muscle precursor cells require myogenic regulatory factors and chromatin modifiers whose concerted action dynamically regulates access to DNA and allows reprogramming of cells towards terminal differentiation. Type 2 deiodinase (D2), the thyroid hormone (TH)-activating enzyme, is sharply upregulated during myoblast differentiation, whereas type 3 deiodinase (D3), the TH-inactivating enzyme, is downregulated. The molecular determinants controlling synchronized D2 and D3 expression in muscle differentiation are completely unknown. Here, we report that the histone H3 demethylating enzyme (LSD-1) is essential for transcriptional induction of D2 and repression of D3. LSD-1 relieves the repressive marks (H3-K9me2-3) on the Dio2 promoter and the activation marks (H3-K4me2-3) on the Dio3 promoter. LSD-1 silencing impairs the D2 surge in skeletal muscle differentiation while inducing D3 expression thereby leading to a global decrease in intracellular TH production. Furthermore, endogenous LSD-1 interacts with FoxO3a, and abrogation of FoxO3-DNA binding compromises the ability of LSD-1 to induce D2. Our data reveal a novel epigenetic control of reciprocal deiodinases expression and provide a molecular mechanism by which LSD-1, through the opposite regulation of D2 and D3 expression, acts as a molecular switch that dynamically finely tunes the cellular needs of active TH during myogenesis. OBJECTIVE: Septic shock is one of various causes of nonthyroidal illness syndrome (NTIS). In humans, the molecular mechanisms involved in NTIS are mostly unknown. The aim of this study was to investigate, in patients with NTIS secondary to septic shock, changes in the expression of genes involved in the actions of thyroid hormones and in the activity of deiodinase enzymes, in two tissues important for protein and energy metabolism, skeletal muscle (SM) and subcutaneous adipose tissue (SAT). DESIGN: Hospitalized patients were divided into a control and a septic shock NTIS group. MEASUREMENT: Serum collection for biochemical measurements, and SM and SAT biopsies for mRNA expression analysis of thyroid hormone receptors (THRB1, THRA1), retinoid X receptors (RXRA, RXRB, RXRG), nuclear receptor corepressor (NCOR1), silencing mediator of retinoid and thyroid hormone receptor (SMRT), steroid receptor coactivator (SRC1), type 1 and 2 deiodinases (D1, D2), monocarboxylate transporter 8 (MCT8), SECIS binding protein 2 (SBP2) and uncoupling protein 3 (UCP3) as well as D1, D2 and D3 enzyme activity measurements. RESULTS: The NTIS group had lower serum TSH, and free T3 and higher rT3 than controls. D1 and D3 were detected in SAT, with no differences found between the two groups; SM had very low D2 activity and again no differences were found between groups; D3 activity in SM was higher in NTIS than controls. SM expression of THRB1, RXRG and D2 was lower and RXRA higher in NTIS than controls. SAT from NTIS patients had lower MCT8, THRB1, THRA1, RXRG and SMRT, and higher UCP3 expression than controls. CONCLUSIONS: In patients with septic shock NTIS tissue responses are orientated to decrease production and increase degradation (muscle) or decrease uptake (adipose tissue) of T3, as well as to decrease thyroid hormone actions. |
375 | Which genes are involved in patient response to warfarin? | The following genes have been associated with patient response to warfarin: CYP2C9, VKORC1, ORM1, CYP4F2, EPHX1, CYP2C18, CYP2C19, CYP3A5, protein S, clotting factor V, PROC, GGCX. | [23208322, 20854800, 19538716, 11213860, 21590310, 16611750, 22952875, 20210733, 18464049, 18034618, 21713343, 22122181, 19752777, 19348697, 20615525, 17496169, 19794411, 22023024, 23342320, 19069171, 21651319, 18752379, 22321278, 19135231] | 482 | PURPOSE: ORM1 is a plasma drug binding protein. Its polymorphism rs17650 (S>F) has been reported to be an important factor affecting the binding ability and effect of antiretroviral protease inhibitors. The aim of this study was to determine whether the ORM1 rs17650 polymorphism also influences warfarin therapy. METHODS: A total of 191 Chinese patients with steady-dose warfarin therapy were enrolled in this study. The patients were studied for warfarin maintenance dose, the ORM1 rs17650 polymorphism, and two polymorphisms previously demonstrated to affect warfarin response [CYP2C9 rs1057910 (3) and VKORC1 rs7294 (-1639 G>A)]. RESULTS: Warfarin dose was partially correlated with the VKORC1 rs7294, CYP2C9 rs1057910 and ORM1 rs17650 polymorphisms. Patients carrying the wild-type of these three genes (n = 96) took a mean dose of 3.0 ± 1.1 mg warfarin, which was significantly higher than that taken by the 52 S patients (2.7 ± 0.7) and 11 S S patients (2.5 ± 0.6 mg) (p = 0.048). CONCLUSION: We identified ORM1 as another polymorphic gene affecting warfarin dose requirements. ORM1 S carriers require lower maintenance doses to achieve and maintain an optimal level of anticoagulation. BACKGROUND: The response to the anticoagulant drug warfarin is greatly affected by genetic polymorphisms in the VKORC1 and CYP2C9 genes. Genotyping these polymorphisms has been shown to be important in reducing the time of the trial and error process for finding the maintenance dose of warfarin thus reducing the risk of adverse effects of the drug. METHOD: We developed a real-time isothermal DNA amplification system for genotyping three single nucleotide polymorphisms (SNPs) that influence warfarin response. For each SNP, real-time isothermal Helicase Dependent Amplification (HDA) reactions were performed to amplify a DNA fragment containing the SNP. Amplicons were detected by fluorescently labeled allele specific probes during real-time HDA amplification. RESULTS: Fifty clinical samples were analyzed by the HDA-based method, generating a total of 150 results. Of these, 148 were consistent between the HDA-based assays and a reference method. The two samples with unresolved HDA-based test results were repeated and found to be consistent with the reference method. CONCLUSION: The HDA-based assays demonstrated a clinically acceptable performance for genotyping the VKORC1 -1639G>A SNP and two SNPs (430C>T and 1075A>C) for the CYP2C9 enzyme (CYP2C9*2 and CYP2C9*3), all of which are relevant in warfarin pharmacogenentics. BACKGROUND: The Azorean population presents the highest standardized mortality rate for cardiovascular diseases (CVD) when compared to mainland Portugal and other populations. Since thrombosis is a common cause of CVD, we assessed four polymorphisms in three thrombotic risk genes - F5 (G1691A), F2 (G20210A) and MTHFR (C677T, A1298C), in 469 healthy blood donors from São Miguel Island (Azores). We also analysed the CYP2C9 (C430T, A1075C) and VKORC1 (G1639A) variants in fifty-eight individuals with predisposition to thrombosis (possessing at least one variation in F5 or F2 genes and one in MTHFR) to evaluate their warfarin drug response genetic profiles. RESULTS: Among the 469 individuals, the data showed that thrombotic risk allele frequencies - 1691A (4.9%), 20210A (1.8%), 677T (41.7%) and 1298C (24.8%) - were similar to other Caucasians, but significantly different from mainland Portuguese (chi2, p < 0.001). The combined analysis of these variants identified twenty-two different genetic profiles (genotype order: F5, F2, MTHFR C677T and A1298C). Complete homozygosity for all wild-type alleles (GG GG CC AA) was present in 11.7%, being GG GG CT AA (22.4%) the most frequent profile. The results also demonstrated that 12.4% (58 out of 469) of São Miguel islanders have increased genetic predisposition to thrombosis. Subsequently, we evaluated these individuals for their warfarin response genetic profiles. The data showed that seven out of fifty-eight individuals are poor metabolizers (two with CYP2C9*2/*2 and five with CYP2C9*2/*3 genotypes). VKORC1 polymorphism analysis identified twelve individuals (20.7%) with AA genotype, who probably will require lower doses of warfarin. The joint analysis of CYP2C9 and VKORC1 revealed that 79.3% (46 out of 58) of the individuals carry at least one polymorphism in these genes. Within these, twenty-five individuals (43.1%) need intermediate and/or low doses of warfarin, if treatment is started. CONCLUSION: The present study demonstrated, for the first time, that São Miguel, and possibly the Azores population, shows significant differences on allele frequencies of thrombotic risk factors when compared to mainland Portugal. This research constitutes a primary approach for future studies on CVD, as well as for the implementation of warfarin dosing protocols using the patient's genotypic information. Warfarin is an anticoagulant available as a racemic mixture. The R- and S-isomers differ with respect to relative plasma concentrations, clearance, potency, sites of metabolism, and cytochrome P450 (CYP) isoenzymes responsible for metabolism. S-Warfarin, the more potent isomer, is metabolized primarily by CYP2C9. Genetic polymorphisms resulting from single amino acid substitutions reduce the metabolic capability of 2C9. A reduction in warfarin metabolism due to genetic polymorphism may explain the increased warfarin response and bleeding episodes in some patients. Clinical studies showed an increased plasma level of S-warfarin, decreased clearance of S-warfarin, increased frequency of bleeding, and prolongation of hospitalization in patients with variant CYP2C9 alleles. Adverse outcomes associated with warfarin possibly could be avoided by identifying patients with variant alleles before therapy and starting therapy at low dosages. BACKGROUND: Warfarin is a highly effective anticoagulant however its effectiveness relies on maintaining INR in therapeutic range. Finding the correct dose is difficult due to large inter-individual variability. Two genes, CYP2C9 and VKORC1, have been associated with this variability, leading to genotype-guided dosing tables in warfarin labeling. Nonetheless, it remains unclear how genotypic information should be used in practice. Navigating the literature to determine how genotype will influence warfarin response in a particular patient is difficult, due to significant variation in patient ethnicity, outcomes investigated, study design, and methodological rigor. Our systematic review was conducted to enable fair and accurate interpretation of which variants affect which outcomes, in which patients, and to what extent. METHODOLOGY/PRINCIPAL FINDINGS: A comprehensive search strategy was applied and 117 studies included. Primary outcomes were stable dose, time to stable dose and bleeding events. Methodological quality was assessed using criteria of Jorgensen and Williamson and data synthesized in meta-analyses using advanced methods. Pooled effect estimates were significant in most ethnic groups for CYP2C9*3 and stable dose (mutant types requiring between 1.1(0.7-1.5) and 2.3 (1.6-3.0)mg/day). Effect estimates were also significant for VKORC1 and stable dose for most ethnicities, although direction differed between asians and non-asians (mutant types requiring between 0.8(0.4-1.3) and 1.5(1.1-1.8)mg/day more in asians and between 1.5(0.7-2.2) and 3.1(2.7-3.6)mg/day less in non-asians). Several studies were excluded due to inadequate data reporting. Assessing study quality highlighted significant variability in methodological rigor. Notably, there was significant evidence of selective reporting, of outcomes and analysis approaches. CONCLUSIONS/SIGNIFICANCE: Genetic associations with warfarin response vary between ethnicities. In order to achieve unbiased estimates in different populations, a high level of methodological rigor must be maintained and studies should report sufficient data to enable inclusion in meta-analyses. We propose minimum reporting requirements, suggest methodological guidelines and provide recommendations for reducing the risk of selective reporting. PURPOSE: This study was designed to delineate the relative frequency of CYP2C9 and VKORC1 polymorphisms known to affect warfarin response in the highly heterogeneous Israeli population. METHODS: Frequencies of CYP2C9 allelic variants CYP2C9*2, CYP2C9*3 and of VKORC1 single nucleotide polymorphisms (snps) -1639G>A and D36Y were determined in genomic DNA of 438 healthy unrelated Israeli volunteers of Jewish, Druze and Arab Moslem descent, using allele specific PCR-RFLP. Genotyping results obtained were confirmed by probe free High Resolution Melt (HRM) Technology. RESULTS: Arab Moslems had a higher frequency of warfarin "sensitive" CYP2C9*2, CYP2C9*3 and VKROC1 -1639G>A alleles (0.21, 0.07 and 0.58, respectively) than both Jews (0.13, 0.11 and 0.57, respectively) and Druze (0.12, 0.06 and 0.53, respectively). Statistically significant differences were found in CYP2C9*2 between Druze and Moslems (p=0.01) and between Jews and Moslems (p=0.016) and in CYP2C9*3 between Druze and Jews (p=0.0086). VKORC1(-1639G>A) was the major gene polymorphism associated with warfarin sensitivity in all 3 subpopulations. In contrast, the warfarin "resistant" VKORC1 D36Y allele was very rare in the Israeli population (0-0.015). The results presented demonstrate that allelic variants in CYP2C9 and VKORC1 are very common in Israel with approximately 95% of Jews, approximately 84% of Druze and approximately 91% of Arab Moslems manifesting at least one known warfarin "sensitive" or "resistant" allele. CONCLUSIONS: Individualized genotype based warfarin therapy is highly relevant in the Israeli population due to the high incidence of genetic variations associated with warfarin sensitivity in all 3 non-mixing subpopulations tested. INTRODUCTION: African-Americans are under-represented in studies assessing contributors to warfarin response. Our primary objective was to determine whether the genes for cytochrome P450 (CYP) 2C9, nicotinamide adenine dinucleotide phosphate, reduced, quinone oxidoreductase (NQO1) and vitamin K epoxide reductase complex subunit 1 (VKORC1) are associated with warfarin dose requirements in African-Americans. PATIENTS AND METHODS: The following factors were assessed: demographics; clinical data; the CYP2C9 Arg144Cys (*2), Ile358Leu (*3) and Asp360Glu (*5); NQO1 Pro187Ser (*1/*2); and VKORC1 G6853C genotypes were analyzed in 115 African-Americans on stable warfarin doses. RESULTS: Allele frequencies were 0.05 for the CYP2C9 *2, *3 or *5 alleles; 0.20 for NQO1 *2; and 0.25 for VKORC1 6853C. Possession of a CYP2C9*2, *3 or *5 allele was associated with a 38% lower warfarin dose compared with the *1/*1 genotype (30 +/- 13 vs 48 +/- 18 mg/week; p = 0.003). Neither the NQO1 *1/*2 nor VKORC1 G6853C genotype was associated with warfarin dose requirements in the population as a whole or in CYP2C9*1 allele homozygotes. Multiple regression analysis revealed that CYP2C9 genotype (p = 0.015), age (p < 0.001) and body surface area (p < 0.001) were jointly associated with warfarin dose requirements, and together explained 33% of the variability in warfarin dose requirements among African-Americans. DISCUSSION: Our data suggest that CYP2C9 genotype, age and body size are important determinants of warfarin dose requirements in African-Americans. Our data further suggest that the VKORC1 G6853C polymorphism alone may not be useful for predicting warfarin dose requirements in this racial group. INTRODUCTION: Warfarin is an anticoagulant that is difficult to administer because of its narrow therapeutic margin and the numerous factors that influence patient response. OBJECTIVE: Demographic, clinical and genetic variables were characterized to establish the appropriate maintenance dosages of warfarin. MATERIALS AND METHODS: The Colombian patients consisted of 145 adults of both sexes. They were in stable anticoagulation status with international normalized ratio between 2 and 3 for at least two months, and without changes in the warfarin commercial preparation or in the dosage. After signing the informed consent, the following data was recorded for each volunteer: age, gender, weight, height, smoker status, co-morbidity, co-medication, International Normalized Ratio (INR), warfarin dose, and commercial brand. Each patient was typed for genes CYP2C9, VKORC1, CYP4F2 and PROC; for 59 patients, the serum levels of warfarin were quantified. The genotyping and the blood quantification were performed by mini-sequencing and HPLC methods, respectively. RESULTS: Age, co-medication with enzymatic inhibitors (amiodarone, sertraline, fluoxetine) or inducers (phenytoin, carbamazepine), and the alleles rs1799853 (*2) and rs1057910 (*3) of the CYP2C9 gene, as well as rs9923231 of the VKORC1 gene were associated with warfarin dose required to achieve anticoagulation with INR of 2-3. These variables were included in a multiple linear regression model for predicting the optimum dose/week of warfarin. This resulted in an algorithm that explained 47.4% of the variability in the dose responses. CONCLUSION: Clinical and pharmacogenetic variables provided a basis for improving the safety and effective dosage of warfarin; however, the use of a pharmacogenetic algorithm will require patient data obtained during clinical trials. Warfarin and other coumarin anticoagulants are widely used clinically, but currently dosing is determined individually on the basis of patient response. There is increasing evidence that genetic factors, together with several non-genetic patient-specific factors, are important determinants of stable dose requirement for these compounds. Genotype for CYP2C9, which encodes the main cytochrome P450 enzyme that metabolizes warfarin, and VKORC1, the gene encoding the warfarin target vitamin K epoxide reductase, together account for approximately 30% of the variability in dose requirement. The past two years have seen several advances in the area of genetic factors affecting coumarin anticoagulant response. In particular, prospective studies have taken place to analyze whether earlier small retrospective studies can be confirmed, and the question of whether genes other than CYP2C9 and VKORC1 are important in determining dose requirement has been examined. So far, no strong evidence that other genes contribute to dose requirement has been found, apart from a minor but novel role for another cytochrome P450 gene, CYP4F2. A recently published whole genome association study confirms that the main genes important in warfarin response are CYP2C9 and VKORC1. Clinical trials comparing genotype-guided and conventional warfarin initiation have suggested that genotyping may be of value, but larger studies are still needed to show clear clinical benefit. Current knowledge of genetic factors affecting other coumarin anticoagulants is more limited and this area requires further study, as does the impact of ethnic variation in genes relevant to coumarin responses. Here we review recent advances in the area of coumarin anticoagulant genetics and its potential clinical application. Warfarin-based anticoagulant therapy is associated with large variability in dose response. Genetic variability in the VKORC1 and CYP2C9 genes is associated with increased warfarin sensitivity. In addition, rare coding region mutations in VKORC1 have been associated with resistance to warfarin. VKORC1 and CYP2C9 variability associated with altered warfarin response is less well characterized in African and mixed-raced populations such as Brazilians. To determine genetic variability associated with altered warfarin response among Brazilian patients, sixty-two adult patients with extreme resistance or sensitivity to warfarin were genotyped for variants in CYP2C9 and VKORC1. Of the 51 patients on low doses of warfarin, the VKORC1--1639 (3673) G>A polymorphism associated with warfarin sensitivity was present in 48 (94.1%), including 97% of Caucasians, 82% of African-descent patients, and all 7 (100%) patients of Indian descent. Additionally, 52.9% of warfarin sensitive patients had at least one CYP2C9*2 or CYP2C9*3 decreased metabolism allele, 63.6% of Caucasians and 54% of African-descent patients. Of the 11 patients on high doses of warfarin, sequencing of VKORC1 revealed a nonsynonymous V66M mutation in two warfarin resistant patients, both of African-descent. Brazilian patients requiring low doses of warfarin have a high frequency of VKORC1 and CYP2C9 variants associated with warfarin sensitivity. The presence of the rare VKORC1 V66M in two warfarin high dose outlier patients implies that this variant may be more frequent among African Brazilians and has implications for future warfarin studies in other populations of African descent. Warfarin is the most widely used oral anticoagulant in the world for patients with venous thrombosis, pulmonary embolism, chronic atrial fibrillation, and prosthetic heart valves. Approximately 30 genes contribute to therapeutic effects of warfarin, and genetic polymorphisms in these genes may modulate its anticoagulant activity. In contrast to monogenic pharmacogenetic traits, warfarin drug response is a polygenic trait, and development of diagnostic tools predictive of adverse reactions to warfarin requires a novel approach. A combination of two strategies, biochemical isolation of allelic variants and linkage disequilibrium association studies, was used to find an association between genetic polymorphisms in the candidate genes and warfarin response. A strong association was found between genetic polymorphisms in six genes, including VKORC1, CYP2C9, PROC, EPHX1, GGCX, and ORM1, and interindividual variability in the anticoagulant effect of warfarin; the strongest predictors were VKORC1 and CYP2C9. Generation of single nucleotide polymorphism (SNP)-based dense genetic maps made it possible to identify haplotypes associated with drugresponse phenotypes. Discrimination between haplotypes associated with warfarin dose phenotypes can be achieved by a limited set of informative polymorphisms (tag SNPs). The use of tag SNPs in pharmacogenomic analysis provides a promising tool for dissecting polygenic traits of drug response. Determining the optimal dose of warfarin for frail elderly patients is a challenging task because of the low dose requirements in such patients, the wide interindividual variability of response, and the associated risk of bleeding. The objective of this study was to address the influence of 13 common variations in eight genes on the maintenance dose of warfarin in a cohort of frail elderly inpatients. For our study, we enrolled 300 Caucasian subjects who were hospital inpatients, with a mean age of 86.7 +/- 6 years. In addition to age, genetic variants of VKORC1, CYP2C9, CYP4F2, and EPHX1 were found to be significant predictor variables for the maintenance dose of warfarin, explaining 26.6% of dose variability. Among 132 patients in whom warfarin therapy was initiated with the same low-dose regimen, we studied the relative influences of genetic and nongenetic factors. The time to first international normalized ratio (INR) > or =2 was influenced by VKORC1 and CYP2C9 genotypes (P = 0.0003 and P = 0.0016, respectively); individuals with multiple variant alleles were at highest risk for overanticoagulation (INR >4) (odds ratio, 12.8; 95% confidence interval, 2.73-60.0). In this special population of frail elderly patients with multiple comorbidities and polypharmacy, we demonstrated the main impact of genetic factors on warfarin response. Warfarin is a commonly used oral anticoagulant with a narrow therapeutic range and large interindividual variability in daily dose. Compared with Caucasians, Chinese are known to require lower doses of warfarin. Differences between Caucasians and Chinese in the allelic frequencies of two genes, CYP2C9 and VKORC1, largely explain the difference in dose requirement. There are other genetic polymorphisms that may further explain the response to warfarin. The VKORC1 genotype is an important determinant of response to warfarin in Chinese, but some genetic variants found in other ethnic groups that have a large effect on warfarin response and dosing are not commonly found in Chinese. Therefore, it is important to recognize and beware of ethnic differences in the pharmacogenetics of the response to warfarin, especially in the design of algorithms to aid dosing in clinical practice. Warfarin is a frequently prescribed anticoagulant in rehabilitation patients. Adverse drug reactions of warfarin were reported as bleeding and cutaneous microvascular thrombosis. Major bleeding, such as intracranial hemorrhage and psoas hematoma, in patients receiving anticoagulation therapy is a rare condition, but sometimes very serious complication that can even be fatal. Patient-specific factors (eg, age, body size, race, concurrent diseases, and medications) explain some of the individual variability in warfarin dose, but genetic factors, which influence warfarin response, explain a significantly higher proportion of the variability in the dose. There are two identified genes that are responsible for the main proportion of the genetic effect: CYP2C9, which codes for the enzyme cytochrome P450 2C9 that metabolizes S-warfarin, and VKORC1, which codes for warfarin's target, vitamin K epoxide reductase. We report a case of intolerance to warfarin dosing, due to impaired drug metabolism in a patient with CYP2C9(*)1/(*)3 and VKORC 1173TT. Fortunately, there are no severe complications. Warfarin is the mainstay of anticoagulation therapy worldwide. Its clinical use, however, is complicated by the fact that it has a narrow therapeutic index with potential bleeding complications. The dosage requirement of warfarin to produce therapeutic anticoagulation varies widely among patients. Recently genetic factors such as the CYP2C9 and VKORC1 genes have been demonstrated to be determinants of warfarin response. CYP2C9 is the enzyme primarily responsible for the metabolic clearance of the S-enantiomer of warfarin. VKORC1 is the target protein of warfarin which recycles the reduced form of vitamin K, an essential cofactor in the formation of the vitamin K-dependent clotting factors. There is strong evidence to support an association between these genetic variants and a therapeutic dose of warfarin. On the basis of these observations, the Food and Drug Administration (FDA) approved a labeling change for warfarin that includes the genetic information of VKORC1 and CYP2C9 as factors influencing interindividual variability in warfarin dosing. The package insert as of August 2007 states that "lower initiation doses should be considered for patients with certain genetic variations in CYP2C9 and VKORC1 enzymes." The FDA has also approved clinical tests for these genetic variants. However, at this time, validated dosing algorithm and evidence to support the clinical utility of genotyping and reliable economic analysis are lacking to recommend for routine CYP2C9 and VKORC1 testing in every patiens before the initiation of warfarin therapy. In this review, we present the results of several prospective randomised controlled trials conducted to test the impact of genotype-guided warfarin dosing in Caucasian and Asian patients initiating warfarin. BACKGROUND: Polymorphisms in the genes encoding the cytochrome P450 2C9 enzyme (CYP2C9) and the vitamin K epoxide reductase (VKORC1) are known to contribute to variability in sensitivity to coumarins. Patients with certain common genetic variants of CYP2C9 (*2 & *3) or a VKORC1 polymorphism (-1639A Allele) require a lower dose of coumarin and are also at higher risk for over-anticoagulation and serious bleeding. In August 2007, the FDA label for warfarin was updated to highlight the benefit of genetic testing to predict warfarin response. AIM: Since the prevalence of these variants in the Lebanese population has not yet been reported, our aim was to determine the genotypes of CYP2C9 and VKORC1 in our population and to compare allele frequencies with previous findings from other ethnic groups. MATERIALS AND METHODS: CYP2C9 (*1/*2/*3) and VKORC1 (*A/*G) allelic variants were assessed by polymerase chain reaction-restriction fragment length polymorphism assays in a diversified sample of 161 unrelated healthy Lebanese volunteers. RESULTS: The allele frequencies of CYP2C9 *2 and *3 were 0.112 and 0.096 respectively, whereas VKORC1-1639A was 0.528. Carriers of the CYP2C9 *2 or *3 represented 34.2% of the subjects, whereas those of the VKORC1-1639A represented 73.9%. CONCLUSION: Our data show no significant difference in the frequency of CYP2C9 allelic variants when compared to the Caucasian population, whereas the allelic frequency of VKORC1-1639A was very high. Over 50% of the Lebanese population seem to be carrying more than two independent risk alleles, and is therefore potentially at high risk of over-anticoagulation. Significant interest in the pharmacogenetics of warfarin therapy has been triggered with the recent package insert update that highlights the potential role of pharmacogenetics in improving the safety and effectiveness of warfarin. We review the evidence of the influence of the two key genes of interest, the cytochrome P450 2C9 gene, CYP2C9, and the vitamin K epoxide reductase complex 1 gene, VKORC1, on warfarin response and discuss the implications of current knowledge for clinical practice. The influence of CYP2C9 and VKORC1 genotypes on warfarin dose requirements has been consistently demonstrated in diverse racial and ethnic patient groups in observational studies and randomized clinical trials. Dosing algorithms have been developed that incorporate clinical, demographic, and genetic information to help select a warfarin starting dose. Furthermore, CYP2C9 variant genotypes have been associated with a significantly increased risk of serious bleeding events. However, evidence to date from prospective, controlled studies has not demonstrated an added benefit of incorporating genotype-guided therapy in improving anticoagulation control or in preventing or reducing the risk of hemorrhagic or thromboembolic complications. Research efforts designed to evaluate the effectiveness of genotype-guided therapy in improving outcomes are under way. However, the routine use of CYP2C9 and VKORC1 genotyping in the general patient population who begin warfarin therapy is not supported by evidence currently available. OBJECTIVE: To investigate potential contributions of genetic variants of cytochrome P-450 2C9 (CYP2C9) and vitamin K expoxide reductase (VKORC1) to the anticoagulation response during the initiation of warfarin therapy in the Han Chinese population. METHODS: A total of 798 Han Chinese patients received long-term warfarin anticoagulant therapy orally after valve replacement in our hospital between 2000 and 2008 were included in this study. Nine single nucleotide polymorphism (SNP) loci [rs12572351 G > A, rs9332146 G > A, rs4917639 G > T, rs1057910 A > C (CYP2C9(*)3), rs1934967 G > T, rs1934968 G > A, rs9923231 C > T (VKORC1-1639 G > A), rs2359612 G > A and rs10871454 C > T] in 2 genes including CYP2C9 and VKORC1, which were possibly correlated with warfarin pharmacokinetics and pharmacodynamics through literature retrieval, were selected and analyzed. Warfarin steady-state dose requirement, time to the INR (the international normalized ratio) within the therapeutic range and percent of the INR of more than 3.5 were compared among genotype subgroups. SNaPshot technique was used to detect gene SNPs; Hardy-Weinberg genetic equilibrium test was used to test population representativeness. RESULTS: CYP2C9(*)3 genotype did not affect the required warfarin dose while it was associated with increased risk of bleeding when treated with routine dosage regimen during the initiation of treatment. The allelic mutation frequency at VKORC1 gene rs10871454G > A and VKORC1-1639G > A SNP loci was 92.04% and 88.03%, respectively and rs10871454 was in perfect linkage disequilibrium with-1639. Patients with VKORC1 rs10871454 genetic mutation required lower warfarin dose in the first 28 days of therapy. VKORC1-1639 genetic polymorphism was also associated with shorter time to the INR within the therapeutic range and increased risk of over-anticoagulation. CONCLUSION: Detecting genetic polymorphism of CYP2C9 and VKORC1 could guide clinical use of warfarin to reduce the risk of adverse reactions including bleeding in patients receiving chronic anticoagulation therapy. |
376 | Which is the molecular weight of the protein angiogenin? | The molecular weight of angiogenin is 14,120 Da. The bovine angiogenin is 14,595 Da | [7585697, 10441122, 10486275, 8574597, 2775757, 1723310, 10673358, 4074709, 18055286] | 483 | The crystal structure of ribonuclease A (RNase A) in complex with pdUppA-3'-p [5'-phospho-2'-deoxyuridine-3'-pyrophosphate (P'-->5') adenosine 3'-phosphate] has been determined at 1.7 A resolution. This dinucleotide is the most potent low molecular weight inhibitor of RNase A reported to date (K(i) = 27 nM) and is also effective against two major nonpancreatic RNases: eosinophil-derived neurotoxin and RNase-4; in all cases, tight binding in large part derives from the unusual 3',5'-pyrophosphate internucleotide linkage [Russo, N., and Shapiro, R. (1999) J. Biol. Chem. 274, 14902-14908]. The design of pdUppA-3'-p was based on the crystal structure of RNase A complexed with 5'-diphosphoadenosine 3'-phosphate (ppA-3'-p) [Leonidas, D. D., Shapiro, R., Irons, L. I., Russo, N., and Acharya, K. R. (1997) Biochemistry 36, 5578-5588]. The adenosine of pdUppA-3'-p adopts an atypical syn conformation not observed for standard adenosine nucleotides bound to RNase A. This conformation, which allows extensive interactions with Asn 67, Gln 69, Asn 71, and His 119, is associated with the placement of the 5'-beta-phosphate of the adenylate, rather than alpha-phosphate, at the site where substrate phosphodiester bond cleavage occurs. The contacts of the deoxyuridine 5'-phosphate portion of pdUppA-3'-p appear to be responsible for the 9-fold increased affinity of this compound as compared to ppA-3'-p: the uracil base binds to Thr 45 in the same manner as previous pyrimidine inhibitors, and the terminal 5'-phosphate is positioned to form medium-range Coulombic interactions with Lys 66. The full potential benefit of these added interactions is not realized because of compensatory losses of hydrogen bonds of Lys 7 and Gln 11 with the terminal 3'-phosphate and the adenylate 5'-alpha-phosphate, which were not predicted by modeling. The results reported here have important implications for the design of improved inhibitors of RNase A and for the development of therapeutic agents to control the activities of RNase homologues such as eosinophil-derived neurotoxin and angiogenin that have roles in human pathologies. This paper reports the isolation and characterization from bovine milk of two proteins: angiogenin-1, a recently discovered angiogenin, and lactogenin, a novel protein. Both proteins were adsorbed on and eluted closely from CM-Sepharose and Mono S. Lactogenin possessed a molecular weight (17 kDa) slightly higher than that of angiogenin-1 (15 kDa). Lactogenin had a higher ribonucleolytic (RNase) activity than angiogenin-1 towards yeast transfer RNA (tRNA). The Km values estimated for the RNase activities of angiogenin-1 and lactogenin were 51 microM and 40 microM respectively. Both were specific for poly C. The optimal pH for the RNase activities of angiogenin-1 and lactogenin was 7.75 and 7.5 respectively. Comparison of the amino acid sequences of cyanogen bromide fragments and the pyroglutaminase-treated N-terminal fragment of lactogenin with the sequence of bovine liver RNase (RNase BL4) revealed identity in residues 3-22, 24, 26-27, 37, 41-44, 46-50, 54, 56, 63, 72-80, and 83. Considerable similarity to the N-terminal sequence of angiogenin-2 was also noted. Both lactogenin and angiogenin-1 inhibited cell-free translation in a rabbit reticulocyte lysate system with an IC(50) below 100 nM. Infectious complications are frequent and often lethal in patients with uremia. Serious alterations in neutrophil function, e.g., phagocytosis, mononuclear cell activation, cytokine production, complement activation, T-cell function, and adhesion molecule expression, have been documented in uremic patients. Uremia per se is a cause of some of these derangements, but much evidence now exists that blood-membrane interaction during dialysis is responsible for many of these abnormalities. This is particularly true when bio-incompatible cellulose-based membranes are used. In many of these patients, newly described granulocyte inhibitory proteins (GIP) can be demonstrated. These two proteins, GIP I and II (28 kD and 9.5 kD, respectively, in molecular weight), block effective bacterial killing, chemotaxis, and oxygen metabolism. It appears that GIP I is a member of the lightchain family, and GIP II is the advanced glycosilation end product of beta 2-microglobulin. Another inhibitory protein, degranulation inhibitory protein (DIP), has been isolated. This protein is 14 kD in molecular weight, and is identical to the angioplastic factor angiogenin. DIP levels are significantly elevated in patients undergoing dialysis. Much still needs to be learned about the interactions of these inhibitory proteins with other soluble inflammatory mediators and, in particular, cytokines. It is clear, however, that profound derangements in immune function take place during uremia and dialytic therapy. Such derangements are likely to play an important role in determining the rate of recovery of renal function and the patient's ability to respond to septic insults. Further insights into the pathogenesis of uremic-dialytic immune dysfunction are already yielding improved patient management and decreased infection rates. The amino acid sequence and disulfide bridges of bovine plasma derived angiogenin were determined by sequencer analysis of the intact protein and fragments derived by enzymatic and chemical digestion. Bovine angiogenin is a single-chain protein of 125 amino acids; it contains six cysteines and has a calculated molecular weight of 14,595. In contrast to the human protein its amino terminus is unblocked. It has the following sequence: H2N-Ala1-Gln-Asp-Asp-Tyr-Arg-Tyr-Ile-His-Phe10-Leu-Thr-Gln-His-Tyr -Asp-Ala-Lys- Pro-Lys20-Gly-Arg-Asn-Asp-Glu-Tyr-Cys-Phe-Asn-Met30-Met-Lys- Asn-Arg-Arg-Leu-Thr - Arg-Pro-Cys40-Lys-Asp-Arg-Asn-Thr-Phe-Ile-His-Gly-Asn50-Lys- Asn-Asp-Ile-Lys-Ala - Ile-Cys-Glu-Asp60-Arg-Asn-Gly-Gln-Pro-Tyr-Arg-Gly-Asp-Leu70- Arg-Ile-Ser-Lys-Ser - Glu-Phe-Gln-Ile-Thr80-Ile-Cys-Lys-His-Lys-Gly-Ser-Ser-Arg90- Pro-Pro-Cys-Arg-Tyr - Gly-Ala-Thr-Glu-Asp100-Ser-Arg-Val-Ile-Val-Val-Gly-Cys-Glu-Asn1 10-Gly-Leu-Pro- Val-His-Phe-Asp-Glu-Ser-Phe120-Ile-Thr-Pro-Arg-His-OH. Disulfide bonds link Cys(27)-Cys(82), Cys(40)-Cys(93), and Cys(58)-Cys(108). Bovine angiogenin is 64% identical with human angiogenin; like the human protein, it is homologous to the pancreatic ribonucleases, with conservation of active site residues. Two regions, 6-22 and 65-75, are highly conserved between the angiogenins but are significantly different from those of the ribonucleases, suggesting a possible role in the molecules' biological activity. Angiogenin is a potent blood-vessel-inducing polypeptide with a molecular weight of 14,000 that has a unique ribonucleolytic activity. First isolated from the conditioned medium of tumour cells, angiogenin has since been purified from normal plasma, which suggested that its propensity to induce neovascularization should be strictly controlled. Modulation of that activity might involve interaction of angiogenin with cell-surface receptors and extracellular matrix of endothelial cells, tight-binding inhibition of both its ribonucleolytic activity and cell binding property by ribonuclease inhibitor, as well as the overall influence of divalent copper, a modulator of angiogenesis. Human angiogenin is a 14-kDa plasma protein with angiogenic and ribonucleolytic activities. Angiogenin binds specifically to aortic smooth muscle cells, activates second messenger pathways, and inhibits their proliferation. Human and bovine aortic smooth muscle cells were used to study the internalization and intracellular fate of human angiogenin at 37 degrees C. Using a specific antibody against angiogenin, we found that the internalized native protein was localized in the perinuclear region at 30 min and then dispersed throughout the cytoplasm. In conditions favoring receptor-mediated endocytosis, internalization of iodinated angiogenin showed a first peak at 5 min and then further increased for up to 24 h. The half-life of the molecule, calculated as 12 h in chase experiments, could contribute to its intracellular accumulation. In cell extracts, in addition to the 14-kDa protein, a 8.7-kDa fragment was observed at 24 h, and three fragments with molecular mass of 10.5, 8.7, and 6. 1 kDa were detected at 48 h. Our data point to a specific internalization and processing of human angiogenin by aortic smooth muscle cells. The first human tumor derived protein with in vivo angiogenic activity to be obtained in pure form has been isolated from serum-free supernatants of an established human adenocarcinoma cell line (HT-29) and named angiogenin. It was purified by cation-exchange and reversed-phase high-performance liquid chromatography; the yield was approximately 0.5 microgram/L of medium. Biological activity of angiogenin was monitored throughout purification by using the chick embryo chorioallantoic membrane assay. Statistical evaluation demonstrates that it displays activity in this system with as little as 35 fmol per egg. Moreover, only 3.5 pmol is required to induce extensive blood vessel growth in the rabbit cornea. The amino acid composition of this basic (isoelectric point greater than 9.5), single-chain protein of molecular weight approximately 14 400 has been determined. The amino terminus is blocked, and the carboxyl-terminal residue is proline. |
377 | List sodium glucose co-transporter-2 (SGLT2) inhibitors that have been FDA approved for type 2 diabetes mellitus treatment. | Canagliflozin, along with dapagliflozin and empagliflozin, are SGLT2 inhibitors approved by the US FDA for use in the treatment of type 2 diabetes. | [22632452, 24705156, 24998153, 19243283, 25414933, 22583331, 24059302, 22548646, 24040872, 24741548, 25488697, 25712444, 25688893, 24025022, 24950857, 22433611, 25059406, 23194084, 23729000, 24633706, 25598831, 24585202, 25255411, 24455799] | 484 | BACKGROUND/OBJECTIVE: Women with type 2 diabetes mellitus (T2DM) are at increased risk for vaginal Candida colonization, perhaps because of glucosuria. Sodium glucose co-transporter 2 (SGLT2) inhibitors, in development for the treatment of T2DM, improve glycemic control by increasing urinary glucose excretion. Vaginal Candida colonization and symptomatic vulvovaginal adverse events (VVAE) were assessed in females with T2DM treated with canagliflozin, a SGLT2 inhibitor. METHODS: In a double-blind study, subjects with T2DM and inadequate glycemic control on metformin were randomized to placebo; canagliflozin 50, 100, 200, 300 mg daily or 300 mg twice daily; or sitagliptin 100 mg daily for 12 weeks. Vaginal swabs for Candida culture were collected from 198 female subjects at baseline and week 12, and during the trial if symptoms consistent with vulvovaginal candidiasis occurred. RESULTS: At baseline, 23/198 (12%) females had vaginal cultures positive for Candida (C. glabrata: 14; C. albicans: 5; other: 4), with age ≤55 years associated with increased risk (odds ratio [OR], 3.5; 95% confidence interval [CI], 1.1-10.7). Of those with negative cultures at baseline, 31% of canagliflozin and 14% of placebo/sitagliptin subjects converted to positive at week 12 (OR, 2.8; 95% CI, 1.0-7.3 for canagliflozin vs. placebo/sitagliptin). Two placebo/sitagliptin (3%) and 16 canagliflozin subjects (10%) experienced VVAE. Positive vaginal culture for Candida species at baseline was a risk factor for VVAE (OR, 9.1; 95% CI, 2.4-34.0). All 9/9 subjects in the canagliflozin group with a vaginal culture taken at the time of the VVAE were positive for Candida species. Most VVAE were treated with antifungal therapy and resolved without study drug interruption; none led to discontinuation. Study limitations include small population, short duration, and not obtaining cultures in all women with VVAE. CONCLUSION: Canagliflozin treatment was associated with an increase in vaginal colonization with Candida species and in VVAE in women with T2DM. Diabetes mellitus is a greatly challenging disease of the 21 century, and the mortality rate due to this insidious disease is increasing worldwide in spite of availability of effective oral hypoglycemic agents. Satisfactory management of glycemic control in patients afflicted with type 2 diabetes mellitus (T2DM) remains a major clinical challenge. Identification of potential pharmacological target sites is therefore continuing as an integral part of the diabetic research. The sodium-glucose co-transporter type 2 (SGLT2) expressed in the renal proximal tubule plays an essential role in glucose reabsorption. Pharmacological blockade of SGLT2 prevents glucose reabsorption and subsequently induces the elimination of filtered glucose via urine, the process is known as 'glucuresis'. Dapagliflozin is a selective inhibitor of SGLT2. The US FDA approved dapagliflozin in January 2014 to improve glycemic control along with diet and exercise in adult patients afflicted with T2DM. It has a potential to decrease glycated hemoglobin and to promote weight loss. Although the mechanism of action of dapagliflozin is not directly linked with insulin or insulin sensitivity, reduction of plasma glucose by dapagliflozin via induction of glucosuria could improve muscle insulin sensitivity. Moreover, dapagliflozin could cause diuresis and subsequently fall in blood pressure. In addition to general discussion on the pharmacology of dapagliflozin, we propose in this review the possibilities of dual antidiabetic effect of dapagliflozin and its possible additional beneficial actions in hypertensive-obese-T2DM patients through its indirect blood pressure-lowering action and reduction of body calories and weight. Long-term clinical studies are however needed to clarify this contention. INTRODUCTION: Maintenance of glucose homeostasis in healthy individuals involves SGLT2 (sodium glucose co-transporter 2)-mediated recovery of glucose from the glomerular filtrate which otherwise would be excreted in urine. Clinical studies indicate that SGLT2 inhibitors provide an insulin-independent means to reduce the hyperglycemia that is the hallmark of type 2 diabetes mellitus (T2DM) with minimal risk of hypoglycemia. AREAS COVERED: The pharmacophore common to the SGLT2 inhibitors currently in development is a diarylmethane C-glucoside which is discussed in this review. The focus is how this pharmacophore was further modified as inferred from the patents publishing from 2009 to 2011. The emphasis is on the strategy that each group employed to circumvent the constraints imposed by prior art and how the resulting SGLT2 potency and selectivity versus SGLT1 compared with that of the lead clinical compound dapagliflozin. EXPERT OPINION: SGLT2 inhibitors offer a new fundamentally different approach for treatment of diabetes. To date, the clinical results suggest that for non-renally impaired patients this class of inhibitors could be safely used at any stage of T2DM either alone or in combination with other marketed antidiabetic medications. Acetylcholinesterase (AChE) is a primary target for Alzheimer's therapy while recently sodium glucose cotransporter 2 (SGLT2) has gained importance as a potential target for Type 2 Diabetes Mellitus (T2DM) therapy. The present study emphasizes the molecular interactions between a new Food and Drug Administration (FDA) approved antidiabetic drug 'Invokana' (chemically known as Canagliflozin) with AChE and SGLT2 to establish a link between the treatment of T2DM and Alzheimer's Disease (AD). Docking study was performed using 'Autodock4.2'. Both hydrophobic and π-π interactions play an important role in the correct positioning of Canagliflozin within SGLT2 and catalytic site (CAS) of AChE to permit docking. Free energy of binding (ΔG) for 'Canagliflozin-SGLT2' interaction and 'Canagliflozin - CAS domain of AChE' interaction were found to be -10.03 kcal/mol and -9.40 kcal/mol, respectively. During 'Canagliflozin-SGLT2' interaction, Canagliflozin was found to interact with the most important amino acid residue Q457 of SGLT2. This residue is known for its interaction with glucose during reabsorption in kidney. However, 'Canagliflozin-CAS domain of AChE' interaction revealed that out of the three amino acids constituting the catalytic triad (S203, H447 and E334), two amino acid residues (S203 and H447) interact with Canagliflozin. Hence, Invokana (Canagliflozin) might act as a potent dual inhibitor of AChE and SGLT2. However, scope still remains in the determination of the three-dimensional structure of SGLT2-Canagliflozin and AChE-Canagliflozin complexes by X-ray crystallography to validate the described data. Since the development of diabetes is associated with AD, the design of new AChE inhibitors based on antidiabetic drug scaffolds would be particularly beneficial. Moreover, the present computational study reveals that Invokana (Canagliflozin) is expected to form the basis of a future dual therapy against diabetes associated neurological disorders. OBJECTIVE: To examine the effects of canagliflozin, a sodium glucose co-transporter 2 inhibitor that lowers blood glucose by increasing urinary glucose excretion (UGE), on asymptomatic bacteriuria and urinary tract infections (UTIs). RESEARCH DESIGN AND METHODS: In a randomized, double-blind, placebo-controlled, multicenter, dose-ranging phase 2 study, subjects with type 2 diabetes with inadequate glycemic control while receiving metformin were enrolled and randomized to one of seven arms - placebo; canagliflozin doses 50 mg, 100 mg, 200 mg, 300 mg daily, or 300 mg twice daily; and sitagliptin 100 mg daily - for 12 weeks. CLINICAL TRIAL REGISTRATION: This study is registered under Clinicaltrials.gov identification number NCT00642278. RESULTS: Canagliflozin increased renal glucose excretion by 35.4-61.6 mg/mg creatinine in the five dose groups. In the placebo group renal glucose excretion was increased by 1.9 mg/mg creatinine, and in the sitagliptin group it decreased by 1.9 mg/mg creatinine. Asymptomatic bacteriuria (ASB) were present in 6.4% of canagliflozin and 6.5% of placebo/sitagliptin (control) subjects at randomization and, at 12 weeks, in 7.7% and 6.3% of subjects, respectively (odds ratio [OR] 1.23; 95% confidence interval [CI], 0.45-3.89). For subjects with initially negative urine cultures at baseline, 3 out of 82 (3.7%) who received controls and 10 out of 207 (4.8%) who received canagliflozin developed bacteriuria (p = 0.76) at week 12. There were 21 adverse event (AE) reports of UTI; 16 (5.0%) in canagliflozin subjects and 5 (3.8%) in control subjects (OR 1.31; 95% CI, 0.45-4.68). CONCLUSIONS: In this trial, when compared with control subjects, canagliflozin increased UGE but was not associated with increased bacteriuria or AE reports of UTI. However, further studies enrolling larger numbers of subjects with longer term exposure to canagliflozin will be necessary to more fully understand the impact of this agent on the risk of developing UTI. Sodium-glucose co-transporters (SGLT2) are mainly expressed in the kidneys and are responsible for the renal handling of glucose load. SGLT2 inhibitors represent the latest oral agents for diabetes treatment. Their unique mechanism of action, which practically spares the insulin secretion or insulin utilization, differentiates the SGLT2 inhibitors from any existing antidiabetic agent. Thus, it is hypothesized that SGLT2 inhibitors can be effectively (and probably safely) combined with any existing antidiabetic agent (including insulin), either as monotherapy, or in dual or triple combinations. All these hypotheses are currently tested in many clinical trials. Currently dapagliflozin, one of the three most advanced SGLT2 inhibitors in the development (along with canagliflozin and empagliflozin), is already in the market in few European countries and canagliflozin has been approved from the Food and Drug Administration (FDA) in US. The evidence so far shows that SGLT2 inhibitors are equally effective to established antidiabetic agents such as metformin or sulfonylureas in their ability to lower HbA1c. On the other hand, SGLT2 inhibitors increase the possibility of genitourinary infections in type 2 diabetic individuals. Their potency in different populations and with different background therapy, but more importantly their short and long term safety remains to be seen. Inhibitors of sodium-glucose co-transporter type 2 (SGLT2) are proposed as a novel approach for the management of type 2 diabetes mellitus (T2DM). Several compounds are already available in many countries (dapagliflozin, canagliflozin, empagliflozin and ipragliflozin) and some others are in a late phase of development. The available SGLT2 inhibitors share similar pharmacokinetic characteristics, with a rapid oral absorption, a long elimination half-life allowing once-daily administration, an extensive hepatic metabolism mainly via glucuronidation to inactive metabolites, the absence of clinically relevant drug-drug interactions and a low renal elimination as parent drug. SGLT2 co-transporters are responsible for reabsorption of most (90 %) of the glucose filtered by the kidneys. The pharmacological inhibition of SGLT2 co-transporters reduces hyperglycaemia by decreasing renal glucose threshold and thereby increasing urinary glucose excretion. The amount of glucose excreted in the urine depends on both the level of hyperglycaemia and the glomerular filtration rate. Results of numerous placebo-controlled randomised clinical trials of 12-104 weeks duration have shown significant reductions in glycated haemoglobin (HbA1c), resulting in a significant increase in the proportion of patients reaching HbA1c targets, and a significant lowering of fasting plasma glucose when SGLT2 inhibitors were administered as monotherapy or in addition to other glucose-lowering therapies including insulin in patients with T2DM. In head-to-head trials of up to 2 years, SGLT2 inhibitors exerted similar glucose-lowering activity to metformin, sulphonylureas or sitagliptin. The durability of the glucose-lowering effect of SGLT2 inhibitors appears to be better; however, this remains to be more extensively investigated. The risk of hypoglycaemia was much lower with SGLT2 inhibitors than with sulphonylureas and was similarly low as that reported with metformin, pioglitazone or sitagliptin. Increased renal glucose elimination also assists weight loss and could help to reduce blood pressure. Both effects were very consistent across the trials and they represent some advantages for SGLT2 inhibitors when compared with other oral glucose-lowering agents. The pharmacodynamic response to SGLT2 inhibitors declines with increasing severity of renal impairment, and prescribing information for each SGLT2 inhibitor should be consulted regarding dosage adjustments or restrictions in moderate to severe renal dysfunction. Caution is also recommended in the elderly population because of a higher risk of renal impairment, orthostatic hypotension and dehydration, even if the absence of hypoglycaemia represents an obvious advantage in this population. The overall effect of SGLT2 inhibitors on the risk of cardiovascular disease is unknown and will be evaluated in several ongoing prospective placebo-controlled trials with cardiovascular outcomes. The impact of SGLT2 inhibitors on renal function and their potential to influence the course of diabetic nephropathy also deserve more attention. SGLT2 inhibitors are generally well-tolerated. The most frequently reported adverse events are female genital mycotic infections, while urinary tract infections are less commonly observed and generally benign. In conclusion, with their unique mechanism of action that is independent of insulin secretion and action, SGLT2 inhibitors are a useful addition to the therapeutic options available for the management of T2DM at any stage in the natural history of the disease. Although SGLT2 inhibitors have already been extensively investigated, further studies should even better delineate the best place of these new glucose-lowering agents in the already rich armamentarium for the management of T2DM. OBJECTIVE: To review available studies of empagliflozin, a sodium glucose co-transporter-2 (SGLT2) inhibitor approved in 2014 by the European Commission and the United States Food and Drug Administration for the treatment of type 2 diabetes mellitus (T2DM). DATA SOURCES: PubMed was searched using the search terms empagliflozin, BI 10773, and BI10773, for entries between January 1, 2000, and December 1, 2014. Reference lists from retrieved articles were searched manually for additional peer-reviewed publications. STUDY SELECTION AND DATA EXTRACTION: All publications reporting clinical trials of empagliflozin were eligible for inclusion. DATA SYNTHESIS: Empagliflozin is a new once-daily oral SGLT2 inhibitor with a mechanism of action that is independent of β-cell function and the insulin pathway. Data from a comprehensive phase III clinical trial program have demonstrated its efficacy as monotherapy, as add-on to other glucose-lowering agents, and in different patient populations. In these studies, empagliflozin resulted in improvements in blood glucose levels as well as reductions in body weight and blood pressure. Empagliflozin was well tolerated and was not associated with an increased risk of hypoglycemia versus placebo. CONCLUSION: The oral antidiabetes agent, empagliflozin, can be used as monotherapy or alongside other glucose-lowering treatments, including insulin, to treat T2DM. The sodium glucose cotransporter 2 (SGLT2) is expressed primarily in the kidneys and is involved in the reabsorption of filtered glucose in the renal tubule. Clinical trials of SGLT2 inhibitors in patients with type 2 diabetes mellitus demonstrate a significant clinical effect in decreasing serum glucose, hemoglobin A1C, body weight, systolic blood pressure, improving β-cell function, and minimizing the risk of hypoglycemia. This report reviews the potentially beneficial effects of SGLT2 inhibitors in type 2 diabetes mellitus, specifically focusing on canagliflozin, the only SGLT2 inhibitor approved for use in the United States. Treatment of type 2 diabetes mellitus (T2DM) continues to present challenges, with many patients failing to achieve glycemic targets. Despite the availability of many oral and injectable anti-diabetic agents, therapeutic efficacy is often offset by undesirable side effects such as hypoglycemia, weight gain and cardiovascular complications. Therefore, the search for new therapeutic agents with an improved benefit-risk profile continues. Recent research has focused on the kidney as a potential therapeutic target, especially because maximal renal glucose reabsorption is increased in T2DM. Under normal physiological conditions, nearly all filtered glucose is reabsorbed in the proximal tubule of the nephron via the sodium/glucose co-transporter 2 (SGLT2). SGLT2-inhibitors are a new class of oral anti-diabetes, which reduce hyperglycemia by increasing urinary glucose excretion independently of insulin secretion or action. Canagliflozin and dapagliflozin in US market, and ipragliflozin and luseogliflozin in Japan market are now available for glycemic control in type 2 diabetics. There are several phase III clinical ongoing trials involving this new class of medications. This review examines some of the key efficacy and safety data from clinical trials of the SGLT2 inhibitors approved, and their future perspectives in the treatment of T2DM. OBJECTIVE: To review the literature and describe the pharmacologic, pharmacokinetic, and pharmacodynamic properties; clinical safety; and efficacy of dapagliflozin, a new drug currently under review by the Food and Drug Administration (FDA) for the treatment of type 2 diabetes. DATA SOURCES: A MEDLINE (1995-November 2011) and ClinicalTrials.gov search was conducted using the terms dapagliflozin, sodium-glucose cotransporter 2 inhibitor, and SGLT2 inhibitor. Reference citations from publications identified were also reviewed. STUDY SELECTION AND DATA EXTRACTION: All English-language studies, including abstracts, evaluating dapagliflozin use in humans were included in this review. DATA SYNTHESIS: Dapagliflozin is the first-in-class oral sodium-glucose cotransporter 2 (SGLT2) inhibitor that represents a new potential therapeutic option for the treatment of type 2 diabetes mellitus. Its mechanism of action is insulin- and insulin-sensitivity independent. Preliminary data suggest that dapagliflozin decreases hemoglobin A(1c), fasting plasma glucose, and postprandial plasma glucose, while also promoting weight loss. In Phase 1, 2, and 3 clinical trials, dapagliflozin has exhibited a safety and tolerability profile similar to that of placebo. CONCLUSIONS: Dapagliflozin is a novel oral antihyperglycemic agent that has demonstrated promise as monotherapy and as synergistic combination therapy with currently available agents in Phase 3 clinical trials. On January 19, 2012, the FDA issued a complete response letter to AstraZeneca and Bristol-Myers Squibb regarding the new drug application for dapagliflozin. The FDA is requesting additional clinical data-from ongoing studies and potentially new clinical trials-to better describe the risk-benefit profile of the drug. Both manufacturers remain committed to the development of dapagliflozin, and there are currently 8 Phase 3 trials ongoing. Dapagliflozin has the potential to be the next new oral agent in the diabetes drug armamentarium. BACKGROUND/AIMS: Some sodium glucose co-transporter 2 (SGLT2) inhibitors are approved for the treatment of patients with type 2 diabetes mellitus (T2DM) with an estimated glomerular filtration rate (eGFR) of ≥45 ml/min/1.73 m(2). The efficacy and safety of canagliflozin, an approved SGLT2 inhibitor, was evaluated in patients with stage 3 chronic kidney disease (CKD; eGFR ≥30 to <60 ml/min/1.73 m(2)). METHODS: This analysis used integrated data from four randomized, placebo-controlled, phase 3 studies that enrolled patients with T2DM and stage 3 CKD. RESULTS are presented for the overall population as well as subgroups with stage 3a CKD (eGFR ≥45 and <60 ml/min/1.73 m(2)) and stage 3b CKD (eGFR ≥30 and <45 ml/min/1.73 m(2)). RESULTS: Among all subjects studied with stage 3 CKD, placebo-subtracted reductions in HbA1c (-0.38 and -0.47%; p < 0.001), body weight (-1.6 and -1.9%; p < 0.001), and systolic blood pressure (-2.8 and -4.4 mm Hg; p < 0.01) were seen with canagliflozin 100 and 300 mg, respectively. Decreases in HbA1c, body weight, and systolic blood pressure were examined in the stage 3a and 3b CKD subgroups, with greater decreases in HbA1c, -0.47% (-0.61, -0.32) and body weight in subjects in stage 3a CKD, -1.8% (-2.3, -1.2) with canagliflozin 100 mg. Initial declines in eGFR were seen early following treatment initiation with canagliflozin, but trended towards baseline over time. The most common adverse events with canagliflozin included genital mycotic infections and adverse events related to reduced intravascular volume likely secondary to osmotic diuresis. CONCLUSION: In subjects with T2DM and stage 3 CKD, canagliflozin reduced HbA1c, body weight, and blood pressure, and was generally well tolerated. Canagliflozin (Invokana™), an oral selective sodium-glucose co-transporter 2 (SGLT2) inhibitor, is under global development with Mitsubishi Tanabe Pharma and Janssen Pharmaceuticals, a subsidiary of Johnson and Johnson, for the treatment of type 2 diabetes mellitus. SGLT2 are mainly located in the proximal tubule of the kidney and are involved in the reabsorption of filtered glucose from the glomeruli into the body. Inhibition of SGLT2 lowers blood glucose in an insulin independent manner as a consequence of blocking reabsorption of filtered glucose in the glomeruli, thereby increasing urinary excretion of glucose and, in turn, potentially reducing bodyweight. Canagliflozin is the first SGLT2 inhibitor to be approved in the USA and is under regulatory review in the EU. This article summarizes the milestones in the development of canagliflozin, leading to its first approval for use in adults with type 2 diabetes. Although several treatment options are available to reduce hyperglycemia, only about half of individuals with diagnosed diabetes mellitus (DM) achieve recommended glycemic targets. New agents that reduce blood glucose concentrations by novel mechanisms and have acceptable safety profiles are needed to improve glycemic control and reduce the complications associated with type 2 diabetes mellitus (T2DM). The renal sodium-glucose co-transporter 2 (SGLT2) is responsible for reabsorption of most of the glucose filtered by the kidney. Inhibitors of SGLT2 lower blood glucose independent of the secretion and action of insulin by inhibiting renal reabsorption of glucose, thereby promoting the increased urinary excretion of excess glucose. Canagliflozin, dapagliflozin, and empagliflozin are SGLT2 inhibitors approved as treatments for T2DM in the United States, Europe, and other countries. Canagliflozin, dapagliflozin, and empagliflozin increase renal excretion of glucose and improve glycemic parameters in patients with T2DM when used as monotherapy or in combination with other antihyperglycemic agents. Treatment with SGLT2 inhibitors is associated with weight reduction, lowered blood pressure, and a low intrinsic propensity to cause hypoglycemia. Overall, canagliflozin, dapagliflozin, and empagliflozin are well tolerated. Cases of genital infections and, in some studies, urinary tract infections have been more frequent in canagliflozin-, dapagliflozin-, and empagliflozin-treated patients compared with those receiving placebo. Evidence from clinical trials suggests that SGLT2 inhibitors are a promising new treatment option for T2DM. AIMS/HYPOTHESIS: In rodent models of diabetes, treatment with sodium glucose co-transporter 2 (SGLT2) inhibitors improves beta cell function. This analysis assessed the effects of the SGLT2 inhibitor, canagliflozin, on model-based measures of beta cell function in patients with type 2 diabetes. METHODS: Data from three Phase 3 studies were analysed, in which: (Study 1) canagliflozin 100 and 300 mg were compared with placebo as monotherapy for 26 weeks; (Study 2) canagliflozin 100 and 300 mg were compared with placebo as add-on to metformin + sulfonylurea for 26 weeks; or (Study 3) canagliflozin 300 mg was compared with sitagliptin 100 mg as add-on to metformin + sulfonylurea for 52 weeks. In each study, a subset of patients was given mixed-meal tolerance tests at baseline and study endpoint, and model-based beta cell function parameters were calculated from plasma glucose and C-peptide. RESULTS: In Studies 1 and 2, both canagliflozin doses increased beta cell glucose sensitivity compared with placebo. Placebo-subtracted least squares mean (LSM) (SEM) changes were 23 (9) and 18 (9) pmol min(-1) m(-2) (mmol/l)(-1) with canagliflozin 100 and 300 mg, respectively (p < 0.002, Study 1), and 16 (8) and 10 (9) pmol min(-1) m(-2) (mmol/l)(-1) (p < 0.02, Study 2). In Study 3, beta cell glucose sensitivity was minimally affected, but the insulin secretion rate at 9 mmol/l glucose increased to similar degrees from baseline with canagliflozin and sitagliptin [LSM (SEM) changes 38 (8) and 28 (9) pmol min(-1) m(-2), respectively; p < 0.05 for both]. CONCLUSIONS/INTERPRETATION: Treatment with canagliflozin for 6 to 12 months improved model-based measures of beta cell function in three separate Phase 3 studies. TRIAL REGISTRATION: Clinicaltrials.gov NCT01081834 (Study 1); NCT01106625 (Study 2); NCT01137812 (Study 3). The kidney plays a key role in glucose homeostasis and the pathophysiology of type 2 diabetes mellitus (T2DM). Sodium glucose co-transporter 2 (SGLT2) inhibitors are a new class of antihyperglycemic agents for the treatment of T2DM with a novel insulin-independent mechanism of action that targets the kidney. The SGLT2 inhibitors decrease renal glucose reabsorption, thereby increasing urinary glucose excretion and lowering plasma glucose levels in patients with hyperglycemia. SGLT2 inhibitor canagliflozin has demonstrated efficacy in improving glycemic control and reducing body weight and blood pressure as monotherapy or as add-on to other antihyperglycemic agents across a broad range of patients with T2DM. Canagliflozin is generally well tolerated, with increased incidences of specific adverse events that are related to the mechanism of SGLT2 inhibition. Findings suggest that canagliflozin is a useful treatment option for patients with T2DM. Treatment of type 2 diabetes (T2DM) continues to present challenges, with significant proportion of patients failing to achieve and maintain glycemic targets. Despite the availability of many oral antidiabetic agents, therapeutic efficacy is offset by side effects such as weight gain and hypoglycemia. Therefore, the search for novel therapeutic agents with an improved benefit-risk profile continues. Recent research has focused on the kidney as a potential therapeutic target, especially because maximal renal glucose reabsorption is increased in T2DM. Under normal physiological conditions, nearly all filtered glucose is reabsorbed in the proximal tubule of the nephron, principally via the sodium-glucose cotransporter 2 (SGLT2). SGLT2-inhibitors are a new class of oral antidiabetics, which reduce hyperglycemia by increasing urinary glucose excretion independently of insulin secretion or action. Clinical results are promising with significant lowering of HbA1c without increased risk of hypoglycemia, reduction of body weight and reduction of systolic blood pressure. Dapagliflozin is the first highly selective SGLT2-inhibitor approved by the European Medecine Agency. Canagliflozin and empagliflozin are undergoing phase III trials. Actual safety issues are an increased risk for genital- and urinary tract infections and a possible increased risk for bladder and breast cancer. This led to refusal of dapagliflozin by the Food and Drug Administration (FDA). A large randomized control trial is therefore warranted by the FDA. This review provides an overview of the current evidence available so far on the therapeutic potential of the SGLT2-inhibitors for the treatment of T2DM. |
378 | What is the gene mutated in the Gaucher disease? | The glucocerebrosidase gene (GBA) | [2349952, 8986634, 7857677, 8556817, 7923859, 2464926, 21223590, 9733040, 11479729, 9175735, 8213821, 14757438, 23936319, 1899336, 16039881, 10882637, 21704274, 17427031, 9187679, 2117855, 8051940, 9295080, 22230121, 20004604] | 485 | Gaucher disease, resulting from the decreased activity of the lysosomal enzyme glucocerebrosidase, is the most prevalent sphingolipid storage disease. Due to considerable heterogeneity of phenotypic expression, it has been subdivided into the nonneurological type 1 disease, and types 2 and 3, the neurological types. We describe homozygosity for the D409H mutation within the glucocerebrosidase gene associated with a unique form of type 3 Gaucher disease. Twelve patients, originating from three Arab sibships, were found to be homozygous for the D409H mutation. They all presented with oculomotor apraxia and a progressive cardiac valve defect with minimal organomegaly. When expressed in human cells in tissue culture, using the T7/EMC/vaccinia virus hybrid expression system, we were able to demonstrate that the mRNA carrying the D409H mutation was less stable than the normal counterpart. Pulse-chase experiments demonstrated that the mutated protein exhibited lower stability than the normal counterpart. Its activity toward the artificial substrate 4-methyl umbelliferyl glucopyranoside was similar to that of the mutated enzymes carrying the N370S or the L444P mutations. However, in loading experiments using lissamine-rhodamine conjugated glucosyl ceramide as a substrate, the recombinant mutated protein carrying the D409H mutation exhibited 28.63 +/- 6.05% of the activity exhibited by the normal enzyme. L444P and N370S mutations exhibited 51.90 +/- 7.16 and 115.75 +/- 12.64% of normal enzyme activity, respectively. Loading of cells homozygous for the D409H mutation demonstrated 10. 05% of the activity shown by normal cells. L444P and N370S homozygous cells demonstrated 25.3 and 98.5% of foreskin fibroblast glucocerebrosidase activity, respectively. We demonstrate that homozygosity for the D409H mutation is a unique case of a peculiar phenotype associated with a specific intracellular glucocerebrosidase activity. Mutation screening of the glucocerebrosidase gene by SSCP analysis revealed an abnormal pattern of exon 10 in two unrelated Italian Gaucher patients. Direct sequencing of the mutated samples identified a G6490-->A transition. The same mutation has been described before in a Japanese patient with Gaucher disease type III. The clinical phenotype of our patients was type I in one whose second allele carried the N370S mutation and type II in the other one with a L444P mutation. In this latter the G6490-->A substitution cancels a normal Msp I site, while on the opposite chromosome the T6433-->C mutation (L444P) introduces a new Msp I site. Thus, digestion with Msp I of the amplified exon 10 is a useful method for identifying the two mutations simultaneously. In the Portuguese population the most frequent form of Gaucher disease is type 1. The N370S glucocerebrosidase gene mutation accounts for 63% of mutated alleles. The frequency of this mutation was accurately determined in the Portuguese population, which does not present an Ashkenazi Jewish genetic background. A gene frequency of 0.0043, with 95% confidence limits between 0.0023 and 0.0063, was obtained studying the genomic DNA of 2000 blood cards randomly sampled from the national neonatal screening program. On the basis of this frequency a significantly high number of homozygotes for the N370S mutation should be expected in the Portuguese population. This finding supports the idea that the majority of homozygotes for this mutation present a very mild clinical phenotype and remain undiagnosed. Gaucher disease results, in most patients, from mutations in the gene encoding glucocerebrosidase. Mutation D409H is the third most frequent in Spanish patients, accounting for 5.7% of all mutated alleles. This allele is associated mainly with the neurological forms of the disease. Recently, homozygosity for the D409H mutation has been associated with a particular phenotype, including specific cardiovascular symptoms. Here we report a second Spanish patient bearing the D409H/D409H genotype with a very early manifestation of the disease. The patient started enzyme replacement therapy at 3 months of age. A common origin for the Spanish D409H alleles was ruled out by haplotype analysis using an internal polymorphism of the glucocerebrosidase gene and two external microsatellite markers. We have compared the substitution pattern of the glucocerebrosidase gene (GBA) and the glucocerebrosidase pseudogene (psGBA), two highly homologous regions under different selective pressures and within the same genomic background. Mutations in GBA may lead to Gaucher disease, an inborn metabolic disorder. Disease-causing mutations and neutral variation in the gene have been compared to neutral variation in the pseudogene. This comparison offers a unique opportunity to better understand the action of purifying selection, since the differences between mutational patterns can be attributed to different selective pressures. A similar frequency of CpG dinucleotides was observed in GBA and in psGBA, and CpG pairs were mutated with the same high frequency in both regions. However, nucleotides not in CpG pairs were more likely to contribute to disease-causing mutation than to accepted polymorphisms. This pattern, which resulted in a lower transition to transversion ratio in the gene, may be due to CpG avoidance on critical regions within exons. Gaucher disease is a heterogeneous disease characterized by impaired activity of the lysosomal enzyme glucocerebrosidase. This heterogeneity is attributed to a large number of mutations in the corresponding gene. In order to test the biochemical properties of some mutations prevalent among Israeli populations, the normal human glucocerebrosidase cDNA and cDNAs carrying mutations N370S, L444P, D409H, recTL, recNcil, P415R and 84GG were coupled to the T7 RNA polymerase promoter in a vaccinia virus-derived expression vector (pTM-1). Recombinant viruses were produced and used to infect human tissue culture cells. RNA and protein stability, recognition by anti-glucocerebrosidase monoclonal antibodies and intracellular enzymatic activity were measured. The results demonstrated that the D409H allele directed synthesis of cytoplasmic RNA with decreased stability compared with its normal counterpart or other mutated forms. The D409H and L444P mutated proteins had lower stability than that of their normal counterpart, while the recNcil-mutated protein was more stable. Only glucocerebrosidase forms harboring leucine at position 444 were recognized by the anti-glucocerebrosidase monoclonal antibodies used (8E4 and 2C7). Measurements of enzymatic activity of the recombinant proteins in cells loaded with a fluorescent glucosylceramide demonstrated that the N370S mutated enzyme had activity similar to that of the normal enzyme. The other mutated enzymes exhibited varying degrees of activities, generally corresponding to the phenotypes with which they are associated. The results presented demonstrate the use of the vaccinia virus-derived expression system and of loading living cells with fluorescent substrate as efficient tools for studying mutants in Gaucher disease and in other lysosomal diseases. The frequency of nine different mutated alleles known to occur in the glucocerebrosidase gene was determined in 247 Gaucher patients, of whom 176 were of Jewish extraction, 2 were Jewish with one converted parent, and 69 were of non-Jewish origin. DNA was prepared from peripheral blood, active glucocerebrosidase sequences were amplified by using the PCR technique, and the mutations were identified by using the allele-specific oligonucleotide hybridization method. The N37OS mutation appeared in 69.77% of the mutated alleles in Jewish patients and in 22.86% of the mutated alleles in non-Jews. The 84GG mutation, which has not been found so far among non-Jewish patients, existed in 10.17% of the disease alleles among Jewish patients. The IVS + 1 mutation constituted 2.26% of the disease alleles among Jewish patients and 1.43% among the non-Jewish patients. RecTL, a complex allele containing four single-base-pair changes, occurred in 2.26% of the alleles in Jewish patients and was found in two (1.43%) of the patients of non-Jewish extraction. Another complex allele, designated "RecNciI" and containing three single-point mutations, appeared in 7.8% of alleles of non-Jewish patients and in only two (0.56%) of the Jewish families. The prevalence of the L444P mutation among non-Jewish Gaucher patients was 31.43%, while its prevalence among Jewish patients was only 4.24%. The prevalence of two other point mutations--D409H and R463C--was 5.00% and 3.57%, respectively, among non-Jewish patients and was not found among the Jewish Gaucher patient population. The prevalence of the R496H mutation, found so far only among Jewish patients, was 1.13%. The results presented demonstrate that seven mutations identify 90.40% of the mutations among Jewish patients and that these seven mutations allow diagnosis of only 73.52% of the non-Jewish patients. Identification of additional mutant alleles will enhance the accuracy of carrier detection. BACKGROUND: Gaucher disease (GD) is a heterogeneous disease characterized by an impaired activity of the lysosomal glucocerebrosidase. This heterogeneity is attributed in part to the existence of a large number of mutations in the corresponding gene. SUBJECTS AND METHODS: To establish genotype-phenotype relationships, we analyzed the residual enzyme activities of six naturally occurring mutations found in Spanish population in the glucocerebrosidase gene [c.160G > A (V15M), c.485T>C (M123T), c.914C>T (P266L), c.1124T>C (L336P), c.1207A>C (S364R) and c.1510-1512delTCT (S465del)]. The mutated genes were subcloned into the mammalian expression vector pCR 3.1 and expressed by transient transfection in COS cells. The enzymatic activity of the expressed protein were measured and compared with the wild-type human glucocerebrosidase cDNA. Also, two previously alleles, c.1226A>G (N370S) and c.1448T>C (L444P), were used for comparative purposes. RESULTS: The residual activity of the expressed proteins using the synthetic substrate (4-methylumbelliferyl-beta-D-glucopyranoside, 4MU-Glu) ranged from 5.5% (for the 3-bp deletion) to 42.7% (for S364R mutation) of the activity of the wild-type enzyme. CONCLUSION: The present analyses may help to better understand the molecular basis and the pathogenesis of Gaucher disease. However, results of expression of mutated enzymes are necessary but not sufficient to explain the ultimate clinical outcome of Gaucher disease. Gaucher disease (GD) is the most common of the lysosomal storage disorders and is caused by defects in the GBA gene encoding glucocerebrosidase (GlcCerase). The accumulation of its substrate, glucocylceramide (GlcCer) is considered the main cause of GD. We found here that the expression of human mutated GlcCerase gene (hGBA) that is associated with neuronopathy in GD patients causes neurodevelopmental defects in Drosophila eyes. The data indicate that endoplasmic reticulum (ER) stress was elevated in Drosophila eye carrying mutated hGBAs by using of the ER stress markers dXBP1 and dBiP. We also found that Ambroxol, a potential pharmacological chaperone for mutated hGBAs, can alleviate the neuronopathic phenotype through reducing ER stress. We demonstrate a novel mechanism of neurodevelopmental defects mediated by ER stress through expression of mutants of human GBA gene in the eye of Drosophila. Gaucher disease is inherited in an autosomal recessive manner and is the most prevalent lysosomal storage disease. Gaucher disease has marked phenotypic variation and molecular heterogeneity, and several simple and complex alleles of the acid beta-glucosidase gene have been identified as causal to this disease. Certain combinations of alleles have been shown to correlate well with the severity of the disease, but many Gaucher disease patients exist whose disease is not explained by any of the published mutations. This study was undertaken to identify mutant alleles in such incompletely characterized Gaucher disease, in an attempt to find further correlations between clinical phenotype and the presence of acid beta-glucosidase alleles. RNA was isolated from Gaucher cell lines and converted to cDNA, the cDNA was amplified by PCR and cloned, and several clones for each allele were sequenced. Several new singly mutated and multiply mutated alleles were identified, and sequence-specific oligonucleotide hybridization was used to verify the presence of these mutations in the genome of these patients. All newly identified mutations occurred only rarely in the Gaucher disease population, making it difficult to determine whether inheritance of a particular combination of alleles always correlates with the clinical manifestations seen in the test patients. Three of the newly described alleles were single missense mutations in exon 8, one was a single missense mutation in exon 5, and the fifth was a complex allele, comprising a series of different point mutations scattered throughout exons 5 and 6.(ABSTRACT TRUNCATED AT 250 WORDS) Gaucher disease (GD) is a disorder of glycosphinglipid metabolism caused by deficiency of lysosomal acid beta-glucosidase (GC), resulting in progressive deposition of glucosylceramide in macrophages. The glucose analogue, N-butyl-deoxynojirimycin (NB-DNJ, Miglustat), is an inhibitor of the ceramide-specific glucosyltransferase (CSG) which catalyzes the first step of glycosphingolipids biosynthesis and is currently approved for the oral treatment of type 1 GD. Using site-directed mutagenesis, we constructed plasmids containing wild-type and several mutations in glucocerebrosidase (GBA) gene. The plasmids were transfected into COS-7 cells and stable transfected cell lines were obtained by geneticin (G418) selection. Cells were cultured during 6 days with medium with or without 10 microM NB-DNJ. The addition of NB-DNJ to COS-7 cell medium leads to 1.3-, 2.1-, 2.3-, 3.6-, and 9.9-fold increase in the activity of S364R, wild-type, N370S, V15M, and M123T GC, respectively. However, no significant changes were observed in the activity of the L444P, L336P, and S465del mutated proteins, but a small decrease in the rare P266L variant was observed. These results suggest that NB-DNJ, in addition to the inhibitory effect on CSG, also works as a "chemical chaperone", increasing the activity of acid beta-glucosidase of wild-type and several GC mutated proteins, including the most frequent N370S mutation. The specific location of the Miglustat binding site in GC is unknown. Potential binding sites in the enzyme have been searched for using computational molecular docking. The searching strategy identified three potential GC binding sites for Miglustat, one being the substrate-binding site of the enzyme, which was the best-ranked site by AutoDock program. Therefore, it is possible that Miglustat exerts its chaperoning activity on acid beta-glucosidase by acting as an inhibitor bound at the active site. This increase on the activity of the acid beta-glucosidase would imply that Miglustat is not only a substrate reducer but also an inhibitor of the GC degradation, with very promising clinical implications for the treatment of GD patients. SHORT INTRODUCTION: Gaucher's disease (GD) is an autosomal recessive disease produced by mutations of the Glucocerebrosidase gene. Carriers are considered to be healthy subjects because there is no manifestation of the disease, but they show signs of macrophage disfunction. The aim of the study was to determine if GD patients and non affected carriers risk suffering other diseases when compared to healthy non-carrier relatives. DESIGN: Epidemiologic study of historic cohorts. The fact that they have one or two mutated alleles has been considered to be the risk factor leading to other conditions (Dementia, Parkinson disease, Ischemic stroke, Ischemic heart disease, Non rheumatic valvular disease, Cancer hematological and non-hematological, Pulmonary fibrosis, Tuberculosis, Gallstones and Schizophrenia). All people, patients, carriers and healthy controls shared the same genetical background and environmental influence. - Patients and relatives enrolled on the Spanish Gaucher Disease Registry were evaluated. STATISTICS: For the Relative-Risk calculation the Mantel-Haenszel test was applied. Yates' correction was used when size sample was too small. A value of p <0.05 was accepted for statistical significance. RESULTS: 370 people, from 79 different families, were surveyed. We received evaluable information from 45 families (56%), totalling 258 people (69%): 59 healthy subjects (Mean age 32. 20, RANGE: 10-85; M 57.63%/F 42.37%), 132 carriers (Mean age 35.91, RANGE: 1-79; M 56.82%/F 43.18%) and 67 patients (Mean age 32.16, Range: 1-76; M 44.78%/F 55.22%. - Relative Risk of suffering any disease with regard to Gaucher's status: Patient vs Healthy 9.69 (95% Confidence interval [CI] 2.00-63.99; p 0.0006). Patient vs Carrier 3.74 (CI 1.53-9.27; p 0.001); Carrier vs Healthy 2.59 (CI 0. 52-12.50; p 0.21). Relative Risk of suffering any disease with regard to sex was 3.96 for female patients (CI 1.01-16.75; p 0.02) and 1.34 for female carriers (CI 0.27-6.75; p = 0.68). CONCLUSION: As a group, Gaucher's patients seem to have a greater risk of suffering other common unrelated diseases than carriers or healthy relatives. This excess of risk is particularly higher among female patients and can not be explained in terms of differences in age. Carrier status doesn't seem to highten the risk of suffering other diseases. Pseudogenes, resulting from duplications of functional genes, contribute to the functional complexity of their parental genes. The glucocerebrosidase gene (GBA), located in a gene-rich region on chromosome 1q 21, is mutated in Gaucher disease. The presence of contiguous, highly homologous pseudogenes for both GBA and metaxin 1 at this locus increases the likelihood of DNA rearrangement. We describe a facile method to identify and analyze recombinant alleles in patients with Gaucher disease. Genomic DNA from 20 patients with recombinant GBA alleles and five controls was evaluated to identify DNA rearrangements or copy number variation using six probes specific for either the GBA gene or pseudogene. Quantitative real-time PCR was performed on genomic DNA, and Southern blot analyses using HincII together with sequencing confirmed the real-time results. Both GBA fusions and duplications could be detected. Different sites of crossover were identified, and alleles resulting from gene conversion could be distinguished from reciprocal recombinant alleles. Quantitative real-time PCR is a sensitive and rapid method to detect fusions and duplications in patients with recombinant GBA alleles. This technique is more sensitive, faster, and cheaper than Southern blot analysis, and can be used in diagnostic laboratories, and to detect other recombinant alleles within the genome. Gaucher disease is the most common lysosomal storage disease with a high prevalence in the Ashkenazi Jewish population but it is also present in other populations. The presence of eight mutations (1226G, 1448C, IVS2+1. 84GG, 1504T, 1604T, 1342C and 1297T) and the complete deletion of the beta-glucocerebrosidase gene was investigated in 25 unrelated non-Jewish patients with Gaucher's disease in Germany. In the Jewish population, three of these mutations account for more than 90% of all mutated alleles. In addition, relatives of two patients were included in our study. Restriction fragment length polymorphism analysis and sequencing of PCR products obtained from DNA of peripheral blood leukocytes was performed for mutation analysis. Gene deletion was detected by comparison of radioactively labelled PCR fragments of both the functional beta-glucocerebrosidase gene and the pseudogene. Among the unrelated patients, 50 alleles were investigated and the mutations identified in 35 alleles (70%), whereas 15 alleles (30%) remained unidentified. The most prevalent mutation in our group of patients was the 1226G (370Asn-->Ser) mutation, accounting for 18 alleles (36%), followed by the 1448C (444Lcu-->Pro) mutation, that was found in 12 alleles (24%). A complete gene deletion was present in two alleles (4%). The IVS1+2 (splicing mutation), the 1504T (463Arg-->Cys) as well as the 1342C (409Asp-->His) mutations were each present in one allele (2%). None of the alleles carried the 84GG (frame-shift), 1604A (496Arg-->His) or the 1297T (394Val-->Leu) mutation. This distribution is different from the Ashkenazi Jewish population but is similar to other Caucasian groups like the Spanish and Portuguese populations. Our results confirm the variability of mutation patterns in Gaucher patients of different ethnic origin. All patients were divided into nine groups according to their genotype and their clinical status was related to the individual genotype. Genotype/phenotype characteristics of the 1226G, 1448C, and 1342C mutations of previous studies were confirmed by our results. Seven members of an Ashkenazi Jewish family with Gaucher disease in 3 successive generations were tested for the presence of the 2 common mutations known to occur in the glucocerebrosidase gene. Genomic DNA from blood or skin fibroblasts of relatives was amplified by using the PCR technique and individual mutations identified by oligonucleotides specific to the mutated sequences. Four individuals were homozygous for a mutation at amino acid 370 (370 mutation) known to occur only in type 1 disease. The other 3 affected relatives were compound heterozygotes for this mutation and for a mutation at amino acid 444 (NciI mutation) which, in the homozygous state, is associated with neurological disease. Clinical severity was more marked in the compound heterozygotes than in the homozygotes. Since the mutation is present in Ashkenazim, molecular diagnosis in families which carry the NciI mutation should prove useful in assessing their risk of the neurologic forms of Gaucher disease. The mutation N370S accounts for 63% of the mutated glucocerebrosidase alleles of Portuguese type 1 Gaucher patients. It has been shown previously that this mutation is linked to the Pv1.1- form of the PvuII polymorphism and suggested that the N370S mutation in glucocerebrosidase alleles has an Ashkenazi Jewish origin. We have found that in Portuguese type 1 Gaucher patients this mutation is also invariably associated with the Pv1.1- haplotype, despite the fact that there is no evidence of Ashkenazi Jewish background in this population. Gaucher's disease (GD) results from a deficiency of the lysosomal enzyme glucocerebrosidase and, in very rare occasions, a deficiency of its activator, the saposin C. The complexity of identification and characterization of mutations in the gene of glucocerebrosidase (GBA1) is caused by a great amount of mutated alleles, the existence of a highly homologous pseudogene and its location in a very rich zone in genes, which promotes the presence of complex alleles. Although genotype-phenotype correlations in EG are not completely established, there are a series of generalities, as the mutation c.1226A>G (N370S) is often associated with a certain degree of neuroprotection and the homozygosity for the c.1448T>C (L444P) mutation presents with neurological symptoms. In Gaucher disease (GD), the inherited deficiency of glucocerebrosidase results in the accumulation of glucocerebroside within lysosomes. Although almost 300 mutations in the glucocerebrosidase gene (GBA) have been identified, the ability to predict phenotype from genotype is quite limited. In this study, we sought to examine potential GBA transcriptional regulatory elements for variants that contribute to phenotypic diversity. Specifically, we generated the genomic sequence for the orthologous genomic region ( approximately 39.4kb) encompassing GBA in eight non-human mammals. Computational comparisons of the resulting sequences, using human sequence as the reference, allowed the identification of multi-species conserved sequences (MCSs). Further analyses predicted the presence of two putative clusters of transcriptional regulatory elements upstream and downstream of GBA, containing five and three transcription factor-binding sites (TFBSs), respectively. A firefly luciferase (Fluc) reporter construct containing sequence flanking the GBA gene was used to test the functional consequences of altering these conserved sequences. The predicted TFBSs were individually altered by targeted mutagenesis, resulting in enhanced Fluc expression for one site and decreased expression for seven others sites. Gel-shift assays confirmed the loss of nuclear-protein binding for several of the mutated constructs. These identified conserved non-coding sequences flanking GBA could play a role in the transcriptional regulation of the gene contributing to the complexity underlying the phenotypic diversity seen in GD. |
379 | Why does the prodrug amifostine (ethyol) create hypoxia? | After the administration of Prodrug amifostine the cells of the tissue prefer anaerobic glycolysis rather than regular cellular aerobic respiration. By the beggining of anaerobic glycolysis the inducible by hypoxia proteins are induced and by all these molecules the hypoxic conditions consist of. | [11379297, 23154884, 11597323, 17852557, 19182669, 17602063, 21590129, 20334641, 8976819, 8783669, 14574457, 11712796, 11984063] | 486 | Placental extracts have been reported to have anti-oxidative and anti-inflammatory activities. Because there is increasing evidence that ionizing radiation induces the release of reactive oxygen species (ROS) and inflammatory cytokines, we examined the protective effects of a placental extract against radiation injury. C57BL/6 mice were exposed to 1 Gy of γ-ray radiation every day for 5 days, and placental extract (1 mg/day) was administrated orally soon after each exposure. At 2 days after the last irradiation, mice were euthanized to examine the numbers, colony-forming capacity, and DNA damage of stem/progenitor cells in the peripheral blood and bone marrow. To understand the related mechanisms, we also measured the levels of intracellular and mitochondrial ROS, and 8-OHdG in the plasma and urine, and IL-6 and TNF-α in the plasma. Compared with the placebo treatment, oral administration of placental extract significantly increased the number and colony-forming capacity, but decreased the DNA damage of bone marrow stem/progenitor cells. However, neither the levels of intracellular and mitochondrial ROS in bone marrow cells, nor the levels of 8-OHdG in the urine and plasma significantly differed between groups. Interestingly, in comparison with the placebo treatment, placental extract significantly decreased the levels of the inflammatory cytokines IL-6 and TNF-α in the plasma. Placental extract significantly attenuated the acute radiation injury to bone marrow-derived stem/progenitor cells, and this protection is likely to be related to the anti-inflammatory activity of the placental extract. Conclusive research has shown that regions of acute/chronic hypoxia, which exist within the majority of solid tumours, have a profound influence on the therapeutic outcome of cancer chemotherapy and radiotherapy and are a strong prognostic factor of disease progression and survival. A strong argument therefore exists for assessing the hypoxic fraction of tumours, prior to patient treatment, and to tailor this treatment accordingly. Tumour hypoxia also provides a powerful physiological stimulus that can be exploited as a tumour-specific condition, allowing for the rationale design of hypoxia-activated anticancer drugs or novel hypoxia-regulated gene therapy strategies. PURPOSE: Tumor hypoxia and low intrinsic radiosensitivity may counteract the efficacy of standard radiotherapy for locally advanced head and neck cancer (HNC). We investigated the involvement of hypoxia-regulated proteins (Hypoxia inducible factors HIF1alpha, HIF2alpha and carbonic anhydrase CA9) in HNC resistance to accelerated and hypofractionated radiotherapy. MATERIALS AND METHODS: Thirty-nine patients with locally advanced HNC received 15 daily fractions of 3.4 Gy amounting to a total tumor dose of 51 Gy (equivalent to 63 Gy in four weeks--one week split); this was combined with platinum chemotherapy and amifostine cytoprotection administered subcutaneously. Immunohistochemical analysis of hypoxia-regulated proteins, namely HIF1alpha, HIF2alpha and CA9, was performed in formalin-fixed paraffin-embedded tissues obtained prior to radio-chemotherapy. RESULTS: HIF1alpha and HIF2alpha were expressed in the nuclei and cytoplasm of cancer cells, while CA9 had a membrane reactivity. A high expression of HIF1alpha, HIF2alpha and CA9 was noted in 21/39 (53.8%), 20/39 (51.3%) and 23/39 (58.9%) cases, respectively. Complete response was obtained in 85.2% of patients and HIF1alpha was marginally related with persistent disease after RT (p = 0.05). HIF1alpha was significantly associated with poor local relapse free survival (LRFS) (p = 0.006) and overall survival (p = 0.008), whilst HIF2alpha was not. A significant association of CA9 expression with poor LRFS was noted (p = 0.01). CONCLUSION: In accord with previously reported studies, high levels of the hypoxia regulated proteins HIF1alpha and CA9 in HNC predict resistance to platinum based radio-chemotherapy. Whether HIF2alpha expressing tumors are more sensitive to larger radiotherapy fractions, compared to standard radiotherapy fractionation, is an issue that deserves further investigation. BACKGROUND: Radioprotective modalities such as dose fractionation and pharmacologic agents such as amifostine have been used to protect bone and other types of normal tissue from the damaging effects of ionizing radiation without significantly impacting tumor kill. To better understand the cellular mechanism of radioprotection of osseous tissue, the authors sought to determine the effect of dose fractionation and amifostine on isolated osteoblasts. METHODS: Isolated primary rat calvarial osteoblasts were exposed to single or fractionated doses of ionizing radiation both with and without amifostine pretreatment. Endpoints included cell growth (n = 4), vascular endothelial growth factor production as measured by enzyme-linked immunosorbent assay (n = 3), and early osteodifferentiation as measured by a quantitative alkaline phosphatase assay (n = 3). RESULTS: Both dose fractionation and amifostine protect osteoblasts from the growth inhibitory effects of ionizing radiation. Fractionation but not amifostine was protective for hypoxia-induced vascular endothelial growth factor production (used as a surrogate marker of normal osteoblast function). Neither fractionation nor amifostine could prevent the inhibitory effect of ionizing radiation on normal osteoblast osteodifferentiation as measured by alkaline phosphatase production. CONCLUSIONS: Both dose fractionation and amifostine have valid roles as radioprotectants for osteoblasts and can act in an additive fashion. Radioprotection of cell growth and viability does not necessarily correlate with preservation of normal cellular function. Combination protocols involving dose fractionation and amifostine may be effective in radioprotection of osteoblasts and normal osseous tissue. After several decades of preclinical and clinical research, the first approved radioprotective drug, amifostine, is being used in clinical practice. Amifostine has been shown to specifically protect normal tissues from damage caused by radiation and chemotherapy. An inactive prodrug, amifostine is converted to an active thiol by dephosphorylation by alkaline phosphatase in the normal endothelium. The hypovascularity and acidity of the tumor environment and the differential expression of alkaline phosphatase in normal and neoplastic tissues contribute to its cytoprotective selectivity. The cytoprotective mechanism of amifostine is complicated, involving free-radical scavenging, DNA protection and repair acceleration, and induction of cellular hypoxia. The U.S. Food and Drug Administration has approved the i.v. use of amifostine to reduce the cumulative renal toxicity associated with repeated administration of cisplatin in patients with advanced ovarian cancer and to reduce the incidence of moderate to severe xerostomia in patients undergoing postoperative radiation treatment for head and neck cancer, where the radiation port includes a substantial portion of the parotid glands. Nonetheless, amifostine has potential applications in many other oncologic settings. Novel schedules and routes of administration are under investigation and may further simplify the use of amifostine, reduce any undesired effects, and considerably broaden its applications. This review summarizes the clinical experience with amifostine and provides insight into future clinical directions. BACKGROUND: Amifostine (WR-2721, delivered as Ethyol) is a phosphorylated aminothiol compound clinically used in addition to cis-platinum to reduce the toxic side effects of therapeutic treatment on normal cells without reducing their efficacy on tumour cells. Its mechanism of action is attributed to the free radical scavenging properties of its active dephosphorylated metabolite WR-1065. However, amifostine has also been described as a potent hypoxia-mimetic compound and as a strong p53 inducer; both effects are known to potently modulate vascular endothelial growth factor (VEGF-A) expression. The angiogenic properties of this drug have not been clearly defined. METHODS: Cancer cell lines and endothelial cells were used in culture and treated with Amifostine in order to study (i) the expression of angiogenesis related genes and proteins and (ii) the effects of the drug on VEGF-A induced in vitro angiogenesis. RESULTS: We demonstrated that the treatment of several human cancer cell lines with therapeutical doses of WR-1065 led to a strong induction of different VEGF-A mRNA isoforms independently of HIF-1alpha. VEGF-A induction by WR-1065 depends on the activation of the eIF2alpha/ATF4 pathway. This up-regulation of VEGF-A mRNA was accompanied by an increased secretion of VEGF-A proteins fully active in stimulating vascular endothelial cells (EC). Nevertheless, direct treatment of EC with amifostine impaired their ability to respond to exogenous VEGF-A, an effect that correlated to the down-regulation of VEGFR-2 expression, to the reduction in cell surface binding of VEGF-A and to the decreased phosphorylation of the downstream p42/44 kinases. CONCLUSIONS: Taken together, our results indicate that amifostine treatment modulates tumour angiogenesis by two apparently opposite mechanisms - the increased VEGF-A expression by tumour cells and the inhibition of EC capacity to respond to VEGF-A stimulation. Amifostine (Ethyol) administered to cancer patients is rapidly cleared from plasma by a biphasic decay with an alpha half-life (T1/2 alpha) of 0.88 min and a T1/2 beta of 8.8 min. The result is that more than 90% of the drug has disappeared from the plasma compartment 6 min after intravenous (i.v.) administration. Only approximately 1% of the dose appears in the ascites. Animal studies indicate that amifostine is primarily excreted in urine-approximately 6% of the dose is excreted in the urine as amifostine and its metabolites WR-1065 and disulphides-which means that a large percentage of the dose is taken up by the tissues. Maximal tissue concentrations of WR-1065 and the disulphides were obtained between 10 and 30 min after an intraperitoneal injection of amifostine in mice, with the lowest concentrations in tumour tissues. Because WR-1065 gives protection to normal tissues rather than rescue, the pharmacokinetic data indicate that amifostine must be given shortly before administration of the cytostatic drug or radiation from which protection is required. For these reasons, amifostine is given to patients as a 15-min i.v. infusion before cisplatin and carboplatin to protect against their dose-limiting toxicities. In some regimens carboplatin is combined with three doses of amifostine because of the high concentration of the active carboplatin species during the first 4 h after administration. When carboplatin was administered as a 15-min i.v. infusion of 400 mg/m2 and amifostine as a 15-min i.v. infusion of 740 mg/m2 just before and 2 and 4 h after carboplatin, the area under the plasma concentration-time curve for ultrafilterable platinum increased from 253 +/- 45 microM.h (n = 6) for carboplatin alone to 305 +/- 63 microM.h (n = 11) for carboplatin+three doses of amifostine. Experiments in nude mice bearing OVCAR-3 xenografts showed that amifostine, given once before cisplatin or three times in combination with carboplatin, did not affect the antitumour effect of these drugs. When amifostine was only given just before carboplatin, it even stimulated the antitumour effect of carboplatin significantly. Controlled clinical trials indicate that amifostine (WR-2721, Ethyol) confers protection from the cumulative hematologic toxicities associated with alkylating agents and organoplatinums. To determine whether amifostine protects primitive hematopoietic progenitors from the cytotoxicity of functionally diverse antineoplastics, formation of the multipotent hematopoietic progenitors colony-forming units-granulocyte-erythroid, macrophage, megakaryocyte (CFU-GEMM) and erythroid burst-forming units (BFU-E) was evaluated using a clonogenic progenitor inhibition assay. Bone marrow mononuclear cells from normal donors were subjected to a 15-minute exposure of medium, amifostine (500 micromol/L), or WR-1065 (100 micromol/L at concentrations approximating peak plasma levels, washed twice, then treated with the antineoplastic for 1 to 6 hours. Colony growth was scored after 14 days of incubation. Amifostine conferred protection against a broader range of antineoplastics than did WR-1065. Amifostine protected CFU-GEMM against cytotoxicity from daunorubicin, mitoxantrone, and paclitaxel (range, 1.29- to 9.57-fold) (P < .05) but did not afford protection against cisplatin, diaziquone, or thiotepa. Similarly, amifostine protected BFU-E against toxicity from doxorubicin, mitoxantrone, paclitaxel, cisplatin, and diaziquone, yielding 3.4- to 65-fold greater colony recovery compared with controls. The high degree of cytoprotection afforded by amifostine derived largely from stimulation of progenitor growth at sublethal chemotherapy concentrations. In the absence of antineoplastic exposure, preincubation with amifostine or WR-1065 enhanced the colony-forming capacity of bone marrow progenitors from six normal donors, increasing recovery of CFU-GEMM and BFU-E up to sevenfold. We conclude that amifostine protects primitive hematopoietic progenitors from a wide range of antineoplastics. This broad hemoprotective effect derives in part from inherent trophic effects on progenitor growth and survival. PURPOSE: The cytoprotective mechanism of amifostine (WR-2721) implies free radical scavenging and DNA repair activities. We investigated additional cytoprotective pathways involving intracellular hypoxia and the activation of the hypoxia-inducible factor (HIF) pathway, a key transcription factor regulating glycolysis, angiogenesis and apoptosis, which is also linked with radioresistance. MATERIALS AND METHODS: The glucose and oxygen levels in the peripheral blood of patients receiving 1000 mg amifostine were determined at various time-points in order to investigate the metabolic changes induced by amifostine. MDA468 breast tumor cell lines were incubated with a high amifostine concentration (10 m M) to overcome the natural resistance of cancer cells to influx of the non-hydrolyzed WR-2721, and the HIF1 alpha protein levels were determined by Western blot analysis. In vivo experiments with Wistar rats were performed in order to assess immunohistochemically changes in the intracellular accumulation of HIF1 alpha induced by amifostine (200 mg/kg). RESULTS: By 30 min following amifostine administration, the hemoglobin oxygen saturation and pO(2) levels had increased in the peripheral blood while glucose levels had reduced, providing evidence that normal tissue metabolism switches to glycolytic pathways. Incubation of cell lines with amifostine resulted in HIF1 alpha induction. In Wistar rats administration of amifostine resulted in increased HIF1 alpha accumulation in normal tissues. CONCLUSIONS: Since it is doubtful whether dephosphorylation of amifostine to the active metabolite WR-1065 occurs within tumoral tissues (an acidic environment that lacks vascular alkaline phosphatase activity), intracellular hypoxia and upregulation of HIF1 alpha represents an additional, normal tissue-specific, amifostine cytoprotective pathway. Intrinsic radioresistance, tumor hypoxia and ability of cancer cells to undergo rapid repopulation during radiotherapy are associated with failure of radiotherapy. Tumors with low alpha/beta-ratio values or hypoxic tumors unable to undergo re-oxygenation, are unlikely to be eradicated with standard radiotherapy. Although the therapeutic efficacy of accelerated regimens based on low-dose per fraction may be high since they minimize the adverse role of rapid tumor repopulation, the cellular compartment with low alpha/beta-ratio values (i.e. hypoxic cells) remains a limiting factor. Accelerated hypofractionation, which may be more effective in such tumors, cannot be safely applied unless normal tissues are protected. In the present study we assessed the feasibility of hypofractionated and accelerated radiotherapy supported by cytoprotection (HypoARC) with high dose daily amifostine. Fifteen breast cancer patients with locally advanced disease entered radiation-dose escalation protocoL Twelve consecutive fractions of 3.5-4Gy (5 fractions/week) were given to the breast/chest wall, supraclavicular and axillary area, within 17 days. A high dose of amifostine, at 1,000 mg flat dose, was given 20 minutes before each radiotherapy fraction. Amifostine administration was well- tolerated with minor side-effects (vomiting in 6 out of 15 and hypotention in 2 out of 15 patients). Radiation induced acute skin toxicity was negligible (grade 3 in 1 out of 15 patients). Ten out of 15 patients survived more than 12 months and 7 out of 15 more than 18 months following HypoARC. None of these patients showed any signs of late sequellae, such as lung and myoskeletal fibrosis, or brachial plexopathy. Complete and partial responses were obtained in 11 out of 15 (73%) and in 4 out of 15 (27%) patients, respectively. High dose daily amifostine during hypofractionated radiotherapy is feasible. HypoARC regimen is well-tolerated, effective and has minimal acute and late toxicity to normal breast, chest and axillary tissues. Amifostine (Ethyol), an inorganic thiophosphate, is a selective broad-spectrum cytoprotector of normal tissues that provides cytoprotection against ionizing radiation and chemotherapeutic agents, thus preserving the efficacy of radiotherapy and chemotherapy. This review summarizes the preclinical data and clinical experience with amifostine, and provides insight into future clinical directions. Amifostine, an inactive pro-drug, is transformed to an active thiol after dephosphorylation by alkaline phosphatase found in the normal endothelium. The absence of alkaline phosphatase in the tumoral endothelium and stromal components, and the hypovascularity and acidity of the tumor environment, may explain its cytoprotective selectivity. The cytoprotective mechanism of amifostine is complicated, involving free radical scavenging, DNA protection and repair acceleration, and induction of cellular hypoxia. Intravenous administration of amifostine 740-900 mg/m(2) before chemotherapy and 250-350 mg/m(2) before each radiotherapy fraction are widely used regimens. The US Food and Drug Administration has approved the use of amifostine as a cytoprotector for cisplatin chemotherapy and for radiation-induced xerostomia. Ongoing trials are being conducted to determine the efficacy of amifostine in reducing radiation-induced mucositis and other toxicities. Novel schedules and routes of administration are under investigation, and may further simplify the use of amifostine and considerably broaden its applications. |
380 | What is considered a reliable technique for the definitive cytogenetic diagnosis of Fanconi anemia homozygosity? | In vitro enhancement of chromosome breakage by diepoxybutane (DEB) and mitomycin C (MMC) are reliable techniques for the definitive cytogenetic diagnosis of Fanconi anemia homozygosity. | [3133104, 8374893, 19278965, 22052692] | 487 | BACKGROUND: Patients with bone marrow failure and undiagnosed underlying Fanconi anemia may experience major toxicity if given standard-dose conditioning regimens for hematopoietic stem cell transplant. Due to clinical variability and/or potential emergence of genetic reversion with hematopoietic somatic mosaicism, a straightforward Fanconi anemia diagnosis can be difficult to make, and diagnostic strategies combining different assays in addition to classical breakage tests in blood may be needed. DESIGN AND METHODS: We evaluated Fanconi anemia diagnosis on blood lymphocytes and skin fibroblasts from a cohort of 87 bone marrow failure patients (55 children and 32 adults) with no obvious full clinical picture of Fanconi anemia, by performing a combination of chromosomal breakage tests, FANCD2-monoubiquitination assays, a new flow cytometry-based mitomycin C sensitivity test in fibroblasts, and, when Fanconi anemia was diagnosed, complementation group and mutation analyses. The mitomycin C sensitivity test in fibroblasts was validated on control Fanconi anemia and non-Fanconi anemia samples, including other chromosomal instability disorders. RESULTS: When this diagnosis strategy was applied to the cohort of bone marrow failure patients, 7 Fanconi anemia patients were found (3 children and 4 adults). Classical chromosomal breakage tests in blood detected 4, but analyses on fibroblasts were necessary to diagnose 3 more patients with hematopoietic somatic mosaicism. Importantly, Fanconi anemia was excluded in all the other patients who were fully evaluated. CONCLUSIONS: In this large cohort of patients with bone marrow failure our results confirmed that when any clinical/biological suspicion of Fanconi anemia remains after chromosome breakage tests in blood, based on physical examination, history or inconclusive results, then further evaluation including fibroblast analysis should be made. For that purpose, the flow-based mitomycin C sensitivity test here described proved to be a reliable alternative method to evaluate Fanconi anemia phenotype in fibroblasts. This global strategy allowed early and accurate confirmation or rejection of Fanconi anemia diagnosis with immediate clinical impact for those who underwent hematopoietic stem cell transplant. We report on a male newborn with multiple congenital abnormalities consistent with the diagnosis of VACTERL association (vertebral, anal, cardiac, tracheo-esophageal fistula, renal, and limb anomalies), who had Fanconi anemia (complementation group B) recognized by the detection of a deletion in chromosome Xp22.2 using an oligonucleotide array. The diagnosis of Fanconi anemia was confirmed by increased chromosomal breakage abnormalities observed in cultured cells that were treated with cross-linking agents. This is the first report in the literature of Fanconi anemia complementation group B detected by oligonucleotide array testing postnatally. |
381 | Can exosomes be detected in urine? | Yes, urinary exosomes can be detected in urine. | [24060994, 24196483, 24069349, 24250247, 23585095, 24058411, 24044569, 24101370, 24315007, 24205503] | 488 | Exosomes are vesicles that are released from the kidney into urine. They contain protein and RNA from the glomerulus and all sections of the nephron and represent a reservoir for biomarker discovery. Current methods for the identification and quantification of urinary exosomes are time consuming and only semi-quantitative. Nanoparticle tracking analysis (NTA) counts and sizes particles by measuring their Brownian motion in solution. In this study, we applied NTA to human urine and identified particles with a range of sizes. Using antibodies against the exosomal proteins CD24 and aquaporin 2 (AQP2), conjugated to a fluorophore, we could identify a subpopulation of CD24- and AQP2-positive particles of characteristic exosomal size. Extensive pre-NTA processing of urine was not necessary. However, the intra-assay variability in the measurement of exosome concentration was significantly reduced when an ultracentrifugation step preceded NTA. Without any sample processing, NTA tracked exosomal AQP2 upregulation induced by desmopressin stimulation of kidney collecting duct cells. Nanoparticle tracking analysis was also able to track changes in exosomal AQP2 concentration that followed desmopressin treatment of mice and a patient with central diabetes insipidus. When urine was stored at room temperature, 4°C or frozen, nanoparticle concentration was reduced; freezing at -80°C with the addition of protease inhibitors produced the least reduction. In conclusion, with appropriate sample storage, NTA has potential as a tool for the characterization and quantification of extracellular vesicles in human urine. Urinary exosome-like vesicles (ELVs) are a heterogenous mixture (diameter 40-200 nm) containing vesicles shed from all segments of the nephron including glomerular podocytes. Contamination with Tamm-Horsfall protein (THP) oligomers has hampered their isolation and proteomic analysis. Here we improved ELV isolation protocols employing density centrifugation to remove THP and albumin, and isolated a glomerular membranous vesicle (GMV)-enriched subfraction from 7 individuals identifying 1830 proteins and in 3 patients with glomerular disease identifying 5657 unique proteins. The GMV fraction was composed of podocin/podocalyxin-positive irregularly shaped membranous vesicles and podocin/podocalyxin-negative classical exosomes. Ingenuity pathway analysis identified integrin, actin cytoskeleton, and Rho GDI signaling in the top three canonical represented signaling pathways and 19 other proteins associated with inherited glomerular diseases. The GMVs are of podocyte origin and the density gradient technique allowed isolation in a reproducible manner. We show many nephrotic syndrome proteins, proteases, and complement proteins involved in glomerular disease are in GMVs and some were only shed in the disease state (nephrin, TRPC6, INF2 and phospholipase A2 receptor). We calculated sample sizes required to identify new glomerular disease biomarkers, expand the ELV proteome, and provide a reference proteome in a database that may prove useful in the search for biomarkers of glomerular disease. Urinary extracellular vesicles (uEVs) are released by cells throughout the nephron and contain biomolecules from their cells of origin. Although uEV-associated proteins and RNA have been studied in detail, little information exists regarding uEV glycosylation characteristics. Surface glycosylation profiling by flow cytometry and lectin microarray was applied to uEVs enriched from urine of healthy adults by ultracentrifugation and centrifugal filtration. The carbohydrate specificity of lectin microarray profiles was confirmed by competitive sugar inhibition and carbohydrate-specific enzyme hydrolysis. Glycosylation profiles of uEVs and purified Tamm Horsfall protein were compared. In both flow cytometry and lectin microarray assays, uEVs demonstrated surface binding, at low to moderate intensities, of a broad range of lectins whether prepared by ultracentrifugation or centrifugal filtration. In general, ultracentrifugation-prepared uEVs demonstrated higher lectin binding intensities than centrifugal filtration-prepared uEVs consistent with lesser amounts of co-purified non-vesicular proteins. The surface glycosylation profiles of uEVs showed little inter-individual variation and were distinct from those of Tamm Horsfall protein, which bound a limited number of lectins. In a pilot study, lectin microarray was used to compare uEVs from individuals with autosomal dominant polycystic kidney disease to those of age-matched controls. The lectin microarray profiles of polycystic kidney disease and healthy uEVs showed differences in binding intensity of 6/43 lectins. Our results reveal a complex surface glycosylation profile of uEVs that is accessible to lectin-based analysis following multiple uEV enrichment techniques, is distinct from co-purified Tamm Horsfall protein and may demonstrate disease-specific modifications. Recent studies indicate that microRNA (miRNA) is contained within exosome. Here we sought to optimize the methodologies for the isolation and quantification of urinary exosomal microRNA as a prelude to biomarker discovery studies. Exosomes were isolated through ultracentrifugation and characterized by immunoelectron microscopy. To determine the RNA was confined inside exosomes, the pellet was treated with RNase before RNA isolation. The minimum urine volume, storage conditions for exosomes and exosomal miRNA was evaluated. The presence of miRNAs in patients with various kidney diseases was validated with real-time PCR. The result shows that miRNAs extracted from the exosomal fraction were resistant to RNase digestion and with high quality confirmed by agarose electrophoresis. 16 ml of urine was sufficient for miRNA isolation by absolute quantification with 4.15×10(5) copies/ul for miR-200c. Exosomes was stable at 4℃ 24h for shipping before stored at -80℃ and was stable in urine when stored at -80°C for 12 months. Exosomal miRNA was detectable despite 5 repeat freeze-thaw cycles. The detection of miRNA by quantitative PCR showed high reproducibility (>94% for intra-assay and >76% for inter-assay), high sensitivity (positive call 100% for CKD patients), broad dynamic range (8-log wide) and good linearity for quantification (R(2)>0.99). miR-29c and miR-200c showed different expression in different types of kidney disease. In summary, the presence of urinary exosomal miRNA was confirmed for patients with a diversity of chronic kidney disease. The conditions of urine collection, storage and miRNA detection determined in this study may be useful for future biomarker discovery efforts. Urinary exosomes have been proposed as potential diagnostic tools. TNF superfamily cytokines and receptors may be present in exosomes and are expressed by proximal tubular cells. We have now studied the expression of selected TNF superfamily proteins in exosome-like vesicles from cultured human proximal tubular cells and human urine and have identified additional proteins in these vesicles by LC-MS/MS proteomics. Human proximal tubular cells constitutively released exosome-like vesicles that did not contain the TNF superfamily cytokines TRAIL or TWEAK. However, exosome-like vesicles contained osteoprotegerin (OPG), a TNF receptor superfamily protein, as assessed by Western blot, ELISA or selected reaction monitoring by nLC-(QQQ)MS/MS. Twenty-one additional proteins were identified in tubular cell exosome-like vesicles, including one (vitamin D binding protein) that had not been previously reported in exosome-like vesicles. Twelve were extracellular matrix proteins, including the basement membrane proteins type IV collagen, nidogen-1, agrin and fibulin-1. Urine from chronic kidney disease patients contained a higher amount of exosomal protein and exosomal OPG than urine from healthy volunteers. Specifically OPG was increased in autosomal dominant polycystic kidney disease urinary exosome-like vesicles and expressed by cystic epithelium in vivo. In conclusion, OPG is present in exosome-like vesicles secreted by proximal tubular epithelial cells and isolated from Chronic Kidney Disease urine. Exosomes are nanovesicles secreted into the extracellular environment upon internal vesicle fusion with the plasma membrane. The molecular content of exosomes is a fingerprint of the releasing cell type and of its status. For this reason, and because they are released in easily accessible body fluids such as blood and urine, they represent a precious biomedical tool. A growing body of evidence suggests that exosomes may be used as biomarkers for the diagnosis and prognosis of malignant tumors. This article focuses on the exploitation of exosomes as diagnostic tools for human tumors and discusses possible applications of the same strategies to other pathologies, such as neurodegenerative diseases. End-stage renal disease (ESRD) requires for its treatment permanent dialysis or kidney transplantation (KT). KT is the best clinical treatment, however, the early function of the allograft varies depending on multiple factors associated with cold ischemia time (CIT) and the allograft rejection process. It is known that serum creatinine is an insensitive and late marker for predicting graft recovery after KT, mainly in patients with delayed graft function (DGF). Neutrophil gelatinase-associated lipocalin (NGAL) is produced in the distal nephron and it is one of the most promising novel biomarkers for acute kidney injury (AKI) and chronic kidney disease (CKD). NGAL has been proposed to be a predictor of organ recovery from DGF after KT from donors after cardiac death. Because nonrenal diseases can also induce NGAL, more information is necessary to validate the sensitivity and specificity of urine and plasma NGAL in clinical samples. The exosomes are vesicles released into the urine from the kidney epithelium and they have been proposed as better source to explore as biomarker of renal dysfunction. The molecular composition of the urinary exosomes could be representative of the physiological or physiopathologic condition of the urinary system. We propose that determination of NGAL in urinary exosomes is a better predictor of kidney dysfunction after KT than other urinary fractions. We analyzed 15 kidney allograft recipients, with a mean age of 36 years (range, 16-60 years) and 75% were male: 11 living donors (LD) and 4 deceased donors (DD). The average length of CIT was 14 hours in DD and less than 1 hour in LD. Three patient developed DGF. Using Western blot analysis, NGAL was detectable in the cellular and exosomal fraction of the urine. The exosomes expressed higher levels of NGAL than the cellular fraction. The expression of NGAL was observed from the first day after transplantation. In the cellular fraction of the urine, no significant differences of NGAL were observed between the patients. However, the median of NGAL expression in the exosomes fraction was significantly higher in DD patient, from the first day after KT (P < .05). Moreover, we noticed that NGAL expression in exosomes remained elevated in the patients with DGF compared with non-DGF patients (P < .05). Considering the highest abundance of NGAL in the urinary exosomes and its correlation with DGF patients, we suggest the exosomal fraction as a more sensitive substrate to evaluate early biomarkers of DGF after KT. Exosomes are small (30-150 nm) vesicles containing unique RNA and protein cargo, secreted by all cell types in culture. They are also found in abundance in body fluids including blood, saliva, and urine. At the moment, the mechanism of exosome formation, the makeup of the cargo, biological pathways, and resulting functions are incompletely understood. One of their most intriguing roles is intercellular communication--exosomes function as the messengers, delivering various effector or signaling macromolecules between specific cells. There is an exponentially growing need to dissect structure and the function of exosomes and utilize them for development of minimally invasive diagnostics and therapeutics. Critical to further our understanding of exosomes is the development of reagents, tools, and protocols for their isolation, characterization, and analysis of their RNA and protein contents. Here we describe a complete exosome workflow solution, starting from fast and efficient extraction of exosomes from cell culture media and serum to isolation of RNA followed by characterization of exosomal RNA content using qRT-PCR and next-generation sequencing techniques. Effectiveness of this workflow is exemplified by analysis of the RNA content of exosomes derived from HeLa cell culture media and human serum, using Ion Torrent PGM as a sequencing platform. |
382 | What is the role of lysine-specific demethylase 1 (LSD1) in hematopoiesis? | LSD1 represents a central regulator of hematopoietic stem and progenitor cells. LSD1 knockdown (LSD1-kd) expanded progenitor numbers by enhancing their proliferative behavior. LSD1-kd led to an extensive expansion of granulomonocytic, erythroid and megakaryocytic progenitors. In contrast, terminal granulopoiesis, erythropoiesis and platelet production were severely inhibited. The only exception was monopoiesis, which was promoted by LSD1 deficiency. Importantly, we showed that peripheral blood granulocytopenia, monocytosis, anemia and thrombocytopenia were reversible after LSD1-kd termination. Extramedullary splenic hematopoiesis contributed to the phenotypic reversion, and progenitor populations remained expanded. LSD1-kd was associated with the upregulation of key hematopoietic genes, including Gfi1b, Hoxa9 and Meis1, which are known regulators of the HSC/progenitor compartment. We also demonstrated that LSD1-kd abrogated Gfi1b-negative autoregulation by crossing LSD1-kd with Gfi1b:GFP mice. There is also epigenetic regulation of hematopoietic differentiation by Gfi-1 and Gfi-1b that is mediated by the cofactors CoREST and LSD1. A short Gfi-1B isoform controls erythroid differentiation by recruiting the LSD1-CoREST complex through the dimethylation of its SNAG domain. The enzymatic domain of LSD1 plays an important role in repressing the TAL1-directed transcription of GAL4 reporter linked to a thymidine kniase minimal promoter. Furthermore, the TAL1-associated LSD1, HDAC1, and their enzymatic activities are coordinately down-regulated during the early phases of erythroid differentiation. Consistent with the rapid changes of TAL1-corepressor complex during differentiation, TAL1 recruits LSD1 to the silenced p4.2 promoter in undifferentiated, but not in differentiated, murine erythroleukemia (MEL) cells. ShRNA-mediated knockdown of LSD1 in MEL cells resulted in derepression of the TAL1 target gene accompanied by increasing dimeH3K4 at the promoter region. Thus, it appears that histone lysine demethylase LSD1 may negatively regulate TAL1-mediated transcription and that the dynamic regulation of TAL1-associated LSD1/HDAC1 complex may determine the onset of erythroid differentiation programs. Furthermore, RUNX1 has been shown to be part of a large transcription factor complex, together with LDB1, GATA1, TAL1, and ETO2 in erythroid cells. RUNX1 interacts with LSD1 and MYEF2 in erythroid cells. MYEF2 is bound in undifferentiated cells and is lost upon differentiation, whereas LSD1 is bound in differentiated cells. Finally, LSD1 also participates in the trans-repressive effects of SALL4. Based on luciferase assays, the amine oxidase domain of LSD1 is important in suppressing SALL4-mediated reporter transcription. In freshly isolated adult mouse bone marrows, both SALL4 and LSD1 proteins are preferentially expressed in undifferentiated progenitor cells and co-localize in the nuclei. Further sequential chromatin immunoprecipitation assay confirmed that these two factors share the same binding sites at the promoter regions of important hematopoietic regulatory genes including EBF1, GATA1, and TNF. | [19497860, 19736520, 22310283, 24163373, 17707228, 22399799, 22699452, 22801375] | 489 | TAL1/SCL (hereafter referred to as TAL1) is a critical transcription factor required for hematopoiesis in which hematopoietic stem cells commit and differentiate to different lineages. During this process, transcription of many genes is turned on and off in part by epigenetic mechanisms. TAL1 has recently been shown to differentially recruit LSD1 and other histone modifying complexes to regulate its target genes. Here, we focus primarily on epigenetic mechanisms that are regulated by TAL1 during normal and malignant hematopoiesis. We discuss how different histone modifying enzymes are recruited by TAL1 and how these enzymatic activities mediate the activating or repressive function of TAL1. Finally, we further explore the possible mechanisms by which dysregulation of the recruitment and activity of histone modifying enzymes contribute to leukemogenesis. TAL1/SCL is a hematopoietic-specific oncogene and its activity is regulated by associated transcriptional co-activators and corepressors. Dysregulation of TAL1 activity has been associated with T-cell leukemogenesis. However, it remains unclear how the interactions between TAL1 and corepressors versus co-activators are properly regulated. Here, we reported that protein kinase A (PKA)-mediated phosphorylation regulates TAL1 interaction with the lysine-specific demethylase (LSD1) that removes methyl group from methylated Lys 4 on histone H3 tails. Phosphorylation of serine 172 in TAL1 specifically destabilizes the TAL1-LSD1 interaction leading to promoter H3K4 hypermethylation and activation of target genes that have been suppressed in normal and malignant hematopoiesis. Knockdown of TAL1 or LSD1 led to a derepression of the TAL1 target genes in T-cell acute lymphoblast leukemia (T-ALL) Jurkat cells, which is accompanied by elevating promoter H3K4 methylation. Similarly, treatment of PKA activator forskolin resulted in derepression of target genes by reducing its interaction with LSD1 while PKA inhibitor H89 represses them by suppressing H3K4 methylation levels. Consistent with the dual roles of TAL1 in transcription, TAL1-associated LSD1 is decreased while recruitment of hSET1 is increased at the TAL1 targets during erythroid differentiation. This process is accompanied by a dramatic increase in H3K4 methylation. Thus, our data revealed a novel interplay between PKA phosphorylation and TAL1-mediated epigenetic regulation that regulates hematopoietic transcription and differentiation programs during hematopoiesis and leukemogenesis. The stem cell protein SALL4 plays a critical role in hematopoiesis by regulating the cell fate. In primitive hematopoietic precursors, it activates or represses important genes via recruitment of various epigenetic factors such as DNA methyltransferases, and histone deacylases. Here, we demonstrate that LSD1, a histone lysine demethylase, also participates in the trans-repressive effects of SALL4. Based on luciferase assays, the amine oxidase domain of LSD1 is important in suppressing SALL4-mediated reporter transcription. In freshly isolated adult mouse bone marrows, both SALL4 and LSD1 proteins are preferentially expressed in undifferentiated progenitor cells and co-localize in the nuclei. Further sequential chromatin immunoprecipitation assay confirmed that these two factors share the same binding sites at the promoter regions of important hematopoietic regulatory genes including EBF1, GATA1, and TNF. In addition, studies from both gain- and loss-of-function models revealed that SALL4 dynamically controls the binding levels of LSD1, which is accompanied by a reversely changed histone 3 dimethylated lysine 4 at the same promoter regions. Finally, shRNA-mediated knockdown of LSD1 in hematopoietic precursor cells resulted in altered SALL4 downstream gene expression and increased cellular activity. Thus, our data revealed that histone demethylase LSD1 may negatively regulate SALL4-mediated transcription, and the dynamic regulation of SALL4-associated epigenetic factors cooperatively modulates early hematopoietic precursor proliferation. Gfi-1 and Gfi-1b are homologous transcriptional repressors involved in diverse developmental contexts, including hematopoiesis and oncogenesis. Transcriptional repression by Gfi proteins requires the conserved SNAG domain. To elucidate the function of Gfi proteins, we purified Gfi-1b complexes and identified interacting proteins. Prominent among these is the corepressor CoREST, the histone demethylase LSD1, and HDACs 1 and 2. CoREST and LSD1 associate with Gfi-1/1b via the SNAG repression domain. Gfi-1b further recruits these cofactors to the majority of target gene promoters in vivo. Inhibition of CoREST and LSD1 perturbs differentiation of erythroid, megakaryocytic, and granulocytic cells as well as primary erythroid progenitors. LSD1 depletion derepresses Gfi targets in lineage-specific patterns, accompanied by enhanced histone 3 lysine 4 methylation at the respective promoters. Overall, we show that chromatin regulatory proteins CoREST and LSD1 mediate transcriptional repression by Gfi proteins. Lineage-restricted deployment of these cofactors through interaction with Gfi proteins controls hematopoietic differentiation. Lysine (K)-specific demethylase 1A (LSD1/KDM1A) has been identified as a potential therapeutic target in solid cancers and more recently in acute myeloid leukemia. However, the potential side effects of a LSD1-inhibitory therapy remain elusive. Here, we show, with a newly established conditional in vivo knockdown model, that LSD1 represents a central regulator of hematopoietic stem and progenitor cells. LSD1 knockdown (LSD1-kd) expanded progenitor numbers by enhancing their proliferative behavior. LSD1-kd led to an extensive expansion of granulomonocytic, erythroid and megakaryocytic progenitors. In contrast, terminal granulopoiesis, erythropoiesis and platelet production were severely inhibited. The only exception was monopoiesis, which was promoted by LSD1 deficiency. Importantly, we showed that peripheral blood granulocytopenia, monocytosis, anemia and thrombocytopenia were reversible after LSD1-kd termination. Extramedullary splenic hematopoiesis contributed to the phenotypic reversion, and progenitor populations remained expanded. LSD1-kd was associated with the upregulation of key hematopoietic genes, including Gfi1b, Hoxa9 and Meis1, which are known regulators of the HSC/progenitor compartment. We also demonstrated that LSD1-kd abrogated Gfi1b-negative autoregulation by crossing LSD1-kd with Gfi1b:GFP mice. Taken together, our findings distinguish LSD1 as a critical regulator of hematopoiesis and point to severe, but reversible, side effects of a LSD1-targeted therapy. |
383 | For the treatment of which conditions can atypical neuroleptic drugs be used? | Atypical neuroloeptic drugs are antipsychotics used in patients with schizophrenia, schizoaffective disorder, delusional disorder, psychotic disorders, psychotic relapse in neuroleptic malignant syndrome and attention deficit hyperactivity disorder when presenting with negativism and conduct disorder. | [11533860, 17347940, 16625511, 10440458, 8891947, 1618284, 16047503, 10320209, 7952245, 10746298, 9384923, 12596031] | 490 | INTRODUCTION: Attention deficit hyperactivity disorder (ADHD) is a neurobiological condition essentially characterised by inattention, hyperactivity and impulsiveness, and has a prevalence of around 5%. Because it is a biological disorder, both boys and girls with ADHD display these same symptoms, but more boys are diagnosed with ADHD (in a ratio of 3 to 1). AIM: To examine the differences between the two sexes, their prevalence and possible female subtypes in ADHD. PATIENTS AND METHODS: We conducted a retrospective study of 172 patients of both sexes who were attended as hospital neuropaediatric outpatients in the year 2004 according to Diagnostic and statistical manual of mental disorders (DSM-IV-TR) criteria. Their ages ranged between 4 and 14 years and they were divided into three groups: under 6, between 6 and 10, and from 11 to 14 years old. The girls were subdivided into four subtypes, in order of greater to lesser prevalence: shy, hypersociable, hyperactive and changeable. RESULTS: Both sexes showed the same response to methylphenidate. Only the group of boys presented other comorbidities such as negativism and conduct disorders; approximately 25% of them required treatment with atypical neuroleptic drugs. CONCLUSIONS: a) Girls have certain specific clinical manifestations within the three common symptoms; b) methylphenidate is equally effective in both sexes; c) only boys display other disorders such as negativism and conduct disorders; and d) the brains of males and females are quite similar, but symptoms are expressed differently depending on environments and levels. During clinical experience with the "atypical" neuroleptic drugs clozapine, risperidone, and zotepine, some patients have shown a marked weight gain. To prove whether weight gain is a relevant side effect of atypical neuroleptics, the charts of all patients admitted with DSM-III-R diagnoses of schizophrenia, schizoaffective disorder, or delusional disorder in the years 1991 to 1995 were evaluated. A retrospective chart review was performed, which included all patients who were treated longer than 2 weeks with a single neuroleptic. The data analysis showed that weight gain must be considered as a common side effect of atypical neuroleptics (clozapine, risperidone, sulpiride, or zotepine). The mean weight gain (3.1, 1.5, 1.9, or 4.3 kg, respectively) was significantly higher than that of patients treated with "classic" neuroleptics (mean, 0.0-0.5 kg) (Kruskal-Wallis, p = 0.01). Young and not obese patients show the highest weight increase. Because weight gain occurs in the first weeks of treatment, particularly in previously untreated subjects, this side effect has to be considered in view of compliance with long-term neuroleptic medication. Acute and late onset movement disorders frequently complicate the treatment of psychosis with typical neuroleptic drugs like haloperidol, but not with atypical neuroleptic drugs like clozapine. Although the neural mechanisms underlying neuroleptic-induced movement disorders remain unknown, alterations in basal ganglia function are likely involved. A potential role for the endogenous opiate peptides in neuroleptic-induced movement disorders is suggested by the immunocytochemical localization of met5-enkephalin (ME) in the striatopallidal projection pathway, and by the increased levels of ME measured by radioimmunoassay in the rat caudate-putamen nuclei (CPN) following haloperidol treatment. We sought to determine whether met5-enkephalin-like immunoreactivity (MELI) in terminal fields within globus pallidus and in perikarya in CPN was differentially altered in rats chronically treated with haloperidol or clozapine. Acrolein-fixed forebrain sections were collected from cohorts of adult rats receiving 21-day oral administration of haloperidol, clozapine, or water. Sections from the three treatment groups were collectively processed for immunocytochemical labeling using varying dilutions of ME antiserum and the avidin-biotin peroxidase method. In globus pallidus, densitometry measures revealed significantly increased levels of immunoperoxidase labeling for ME in haloperidol-treated, but not in clozapine-treated animals. In CPN, optical densitometry as well as cell counting measurements also showed a significant increase in MELI only in the haloperidol-treated group. These results support the concept that alterations in endogenous opiate peptides in basal ganglia may contribute to movement disorders seen in patients receiving typical neuroleptic drugs.(ABSTRACT TRUNCATED AT 250 WORDS) The study examines the effect of different types of antipsychotic treatment on the health related quality of life (HRQL) of people with schizophrenia under naturalistic outpatient treatment conditions. In a prospective study design, 307 schizophrenic patients were followed over a period of 2.5 years. HRQL, clinical characteristics, and type of antipsychotic medication were assessed five times every 6 months. HRQL was assessed by the SF-36. Random effect regression models were computed for the SF-36 mental (MCS) and physical (PCS) component scores. Propensity scores were included in the regression models to reduce a possible sample selection bias. Monotherapeutic treatment with new atypical neuroleptic drugs had a more positive effect on the mental health related quality of life (MCS) in comparison to treatment with polypharmacological treatment but not with oral conventional antipsychotics. Monopharmaceutical treatment with depot-antipsychotic drugs had a more positive effect on the physical health related quality of life (PCS) in comparison to polypharmacological treatment. Study results indicate that atypical antipsychotic drugs are not superior to conventional antipsychotics with regard to the effect on QOL. However, monopharmaceutical treatment can be assumed to be more effective in improving mental and physical related QOL than polypharmaceutical treatment. Neuroleptic malignant syndrome (NMS) was first recognized as a life-threatening complication of dopamine receptor antagonists characterized by extrapyramidal disturbances, hyperthermia, and elevated serum creatine kinase levels. Concepts of NMS have changed because medications other than classic neuroleptic drugs have been implicated as triggering agents and because syndromes identical to NMS have been observed in patients with Parkinson's disease withdrawn from their medication or suffering akinetic hyperthermic parkinsonian crisis. The neurochemical key features in all these conditions are probably functional dopamine deficiency and ensuing hyperactivity of excitatory amino acid neurotransmission in the basal ganglia and hypothalamus. Recognition of NMS is the most important step in its management; the outcome is good if causative drugs are discontinued or if parkinsonian therapy is readjusted. Supportive care includes management of hyperthermia and fluid replacement. Controversial therapeutic measures include the application of dopamine receptor agonists, excitatory amino acid antagonists, or dantrolene. Psychiatric patients with a history of NMS and psychotic relapse necessitating neuroleptic drugs do not commonly redevelop NMS when reexposed to dopamine receptor antagonists but may be treated most safely with atypical neuroleptic drugs such as clozapine. Recent studies suggest that clozapine is more effective than typical neuroleptics for patients with treatment-resistant schizophrenia. Although other investigations suggest that clozapine may also be at least as effective, and probably more so, than typical neuroleptics for individuals with acute psychosis, the toxicity of this drug has caused its use to be restricted to patients who have demonstrated resistance to previous treatment. The hypothesis behind this article, however, is that clozapine may not only be more effective than typical neuroleptics for individuals with "first-episode" schizophrenia but may also lead to a better long-term course in such patients. This hypothesis is based on the clinical literature concerning clinical and biological response to typical and atypical neuroleptic drugs, as well as on preliminary findings from studies of clinical, neuroendocrine, and biochemical effects that occur during treatment with haloperidol but not with clozapine. When examined in light of Wyatt's recent proposal that each period of symptom exacerbation may lay the groundwork for further symptoms and for increasing syndrome severity, the data suggest that clozapine, despite its disturbing side-effect profile, should be studied in controlled double-blind clinical trials during patients' first episode of schizophrenia. If such investigations show that clozapine is more effective than typical neuroleptics for patients with first-episode schizophrenia and results in a better long-term course, then its benefits and risk as a routine first-line treatment for schizophrenia can be considered. The findings of these studies may also lead us to the regular clinical use of new agents that are less toxic than clozapine but have similar clinical and biological profiles. While the treatment of positive symptoms of patients with schizophrenic psychosis appeared until recently to be solely pharmacotherapeutic, new research findings show the efficacy of cognitive-behavioural psychotherapy (CBT) on positive symptoms in chronic psychotic patients. In addition, the effectiveness even in acute and recent-onset psychosis could be shown in some studies. The effects of CBT and standard care in psychosis compared to standard care alone and to other psychosocial interventions plus standard care are reviewed. The results of several studies and one meta-analysis show that CBT in schizophrenia patients has a direct effect on psychotic symptoms such as hallucinations as well as on relapse prevention. In routine settings,however,CBT has until now only rarely been delivered to these patients. In so-called large pragmatic trials, which might be subsumed as phase IIIb studies, the effects are tested. The therapeutic approach with the components of CBT for psychosis are described: building a therapeutic relationship, cognitive-behavioural coping strategies, developing an understanding of the experience of psychosis,working on hallucinations and delusions, addressing negative self-evaluations, anxiety, and depression,managing risk of relapse and social disability. Further clinical implications are described (capability of learning the therapeutic strategies, deliverability in broader clinical settings, acceptability by patients, combination with atypical neuroleptic drugs,and treatment of choice in risk populations). |
384 | Which are the characteristics of Andersen syndrome? | the characteristics of Andersen syndrome are abnormal QT-U complex, ventricular arrhythmia, periodic paralysis, and facial and skeletal dysmorphisms | [16859779, 12909315, 17272325, 20609799, 10406668, 16769944, 15269659, 12689820, 19445372, 12536108, 17119796, 17395133, 19570891, 8080508, 17399643, 21317470, 20306271, 17582433, 18554214, 12032359, 20382953, 23644778, 10190827, 22589293, 15176430, 16877549, 15831539, 12148092, 16571646] | 491 | In this report we describe the case of a 42-year-old woman who experienced an episode of near drowning during recreational swimming. A diagnosis of Andersen-Tawil syndrome was made based on the patient's dysmorphic features, characteristic T-U-wave patterns and ventricular arrhythmias. To our knowledge, this is the first report of a swimming-triggered cardiac event in a patient with Andersen-Tawil syndrome. OBJECTIVE: The Andersen's syndrome is a hereditary disease, which is characterized by cardiac arrhythmias, periodic paralysis and dysmorphic features. Recently, mutations of the KCNJ2 gene, which encodes the inward rectifying potassium channel subunit Kir2.1, have been identified in affected individuals. However, the functional effects of these mutations have not yet been fully elucidated. METHODS AND RESULTS: To clarify this situation we generated known Andersen disease mutants of KCNJ2 which did not yield any measurable K(+) currents in CHO cells indicating that the Andersen mutants failed to form functional homomultimeric complexes. EGFP-tagged KCNJ2 wild-type and mutant channels distributed in a similar homogeneous pattern in the cell membrane suggesting that protein trafficking was not altered by the Andersen mutations but rather implicating that the mutations rendered the KCNJ2 channel non-functional. In heterologous coexpression experiments the Andersen mutants exerted a dominant-negative effect on wild-type KCNJ2. However, the extent of suppression varied between the different KCNJ2 mutants. Given our results in CHO cells, we expressed the disease mutant KCNJ2-S136F in neonate rat cardiomyocytes using adenoviral gene transfer to test the effect of Andersen mutants on native I(K1). I(K1) density was indeed significantly reduced in KCNJ2-S136F-infected cells (n=9) compared to control cells (n=9) over a voltage range from -70 to -150 mV (P<0.05). CONCLUSION: These results support that Kir2.x channels are a critical component of native I(K1) in neonate rat cardiomyocytes and that a dominant-negative suppression of I(K1) in native cells is the pathophysiological correlate of the Andersen's syndrome. Andersen-Tawil syndrome is an uncommon inherited autosomal disorder characterized by a prolonged QT interval, periodic paralysis, and dysmorphic features. The deleterious effects of cardioplegia on periodic paralysis and cardiac arrhythmia are unknown, and no studies have reported the performance of cardiac surgery in patients with Andersen-Tawil syndrome. We present a case of successful cardiac surgery in a patient with Andersen-Tawil syndrome, without using cardioplegia. Andersen syndrome is a rare entity and comprises potassium sensitive periodic paralysis, ventricular arrhythmia, and an unusual facial appearance; syncope and sudden death have also been reported. The recognition of the characteristic face permits an early diagnosis in order to detect the severe systemic manifestations that are associated with this syndrome. The genetic defect is not linked to any other form of potassium sensitive periodic paralysis nor is it related to that of the long QT syndrome; nevertheless, a prolonged QT interval can be detected in a significant proportion of the cases. Sixteen cases of this syndrome have been described. We report on a three-generation family with 10 affected members. To our knowledge, this is the largest number of cases reported in one family. We noted some additional minor anomalies such as broad forehead and malar hypoplasia. Our patients had variable expression in the classical triad and of the severity of the systemic manifestations. Five of 8 affected studied members did not have a long QTc, which has been suggested as a constant finding in this syndrome. Andersen syndrome includes a clinical triad with periodic paralysis, cardiac arrhythmia and dysmorphic features most often mild but relevant. It is a potassium channelopathy due to mutation of KCJN2 gene coding for Kir 2.1 protein. We report a familial case with mutation R218W of Kir 2.1 and discuss the main phenotypic and genetic aspects of Andersen syndrome. Muscle manifestations are essentially a periodic paralysis most often of hypokaliemic type. Muscle biopsy reveals tubular aggregates but can be normal as it is shown in the same patient in our kindred. Our proband complained of paralytic attacks since childhood and at adult age she demonstrated a mild permanent deficit of pelvic girdle muscles as it has been described in other types of periodic paralysis after a long duration course. Cardiac manifestations may include in a variable manner a long QT syndrome, premature ventricular contractions, complex ventricular ectopy, polymorphic or bidirectional ventricular tachycardia. Imipramine had a positive effect on arrhythmia in our case. Dysmorphic features are often mild and have to be cautiously looked for as a clue to the diagnosis of Andersen syndrome. They can be easily overlooked if not systematically looked for. Clinical expressivity is variable including in the same family. In our observation, the daughter showed a complete triad, early expressed, which allowed the diagnosis. Her father was late diagnosed on ventricular dysrhytmia but without muscle manifestations and dysmorphic features. Since KCJN2 gene mutation identification, locus heterogeneity of Andersen syndrome was shown. Andersen syndrome kindreds without mutations in KCNJ2 were clinically indistinguishable from KCNJ2-associated subjects. KCNJ2 gene encodes the inward rectifier K+ channel Kir2.1 which plays an important role in maintaining membrane potential and during the terminal phase of cardiac action potential repolarization. Several studies showed a dominant negative effect of the mutation on Kir 2.1 channel function. Andersen-Tawil syndrome includes a clinical triad consisting of periodic paralysis, cardiac arrhythmia, and usually mild but diagnostically useful dysmorphic features. This potassium channelopathy is due to mutation of the KCNJ2 gene encoding the protein Kir 2.1. The main muscular manifestation is periodic paralysis, usually of the hypokalemic type. Muscle biopsy may reveal tubular aggregates or be normal, as in our patient. Cardiac manifestations are variable and may include a long QT syndrome, premature ventricular contractions, complex ventricular ectopy, and polymorphic or bidirectional ventricular tachycardia. Imipramine therapy had a positive effect on arrhythmia in our patient. Dysmorphic features provide a diagnostic clue but may be difficult to identify and should thus be methodically sought. Clinical expression is variable, even within the same family. Since the culprit gene KCNJ2 was identified, locus heterogeneity has been shown in Andersen-Tawil syndrome. Kindreds without KCNJ2 mutations are clinically indistinguishable from those with mutations. Kir2.1 is an inward rectifier K+ channel with important roles in maintaining membrane potential and during the terminal phase of cardiac action potential repolarization. Several studies show a dominant negative effect of KCNJ2 mutation on Kir 2.1 channel function. INTRODUCTION: Recent advances in molecular genetic research have provided new insights into severe ventricular arrhythmias related to channelopathies. CASE REPORT: A case of Andersen's syndrome followed during fourteen years is reported. This rare familial periodic paralysis is characterized by its association with dysmorphic features (micrognatia) and ventricular arrhythmias. COMMENTS: Andersen's syndrome has been attributed to a mutation in the KCNJ2 gene which is involved not only in stabilizing cardiac rhythm, but also in modulating the excitability of skeletal muscle and in morphogenesis. This disease must be distinguished from hyperkalemic periodic paralysis due to a mutation in the skeletal muscle sodium channel gene (SCN4A) and from hypokalemic periodic paralysis related to dihydropyridine receptor mutation (CACNL1A3). Furthermore, it may not be confused with others rhythmic channelopathies (long QT syndromes, catecholaminergic polymorphic ventricular tachycardia and Brugada's syndrome). Andersen syndrome (AS) is a rare disease characterized by the presence of periodic paralysis (PP), cardiac arrhythmia and dysmorphic abnormalities. We report herein the first Brazilian patient presenting AS who also had obesity, obstructive sleep apnea (OSA) and daytime sleepiness. Clinical and genetic evaluation of six family members demonstrated that four had dysmorphic abnormalities but none had PP or cardiac arrhythmia. Sequencing of KCNJ2 revealed the R218W mutation in the index patient and her 6-year-old daughter, who presented dysmorphic abnormalities (micrognathia, clinodactyly of fourth and fifth fingers, short stature) and OSA. Three relatives had clinodactyly as the only manifestation but the R218W mutation was absent, suggesting that this characteristic may be influenced by another gene. OSA accompanied by dysmorphic features may be related to AS. Andersen's syndrome is a rare disorder that has been defined with a triad: periodic paralysis, cardiac arrhythmia, and development anomalies. Muscle weakness has been reported in two-thirds of the patients. KCNJ2 remains the only gene linked to Andersen's syndrome; this gene encodes for the alpha-subunit of the strong inward-rectifier K+ channel Kir2.1. Several studies have shown that Andersen's syndrome mutations lead to a loss of function of the K+ channel activity in vitro. However, ex vivo studies on isolated patient muscle tissue have not been reported. We have performed muscle biopsies of controls and patients presenting with clinically and genetically defined Andersen's syndrome disorder. Myoblasts were cultured and characterized morphologically and functionally using the whole cell patch-clamp technique. No morphological difference was observed between Andersen's syndrome and control myoblasts at each passage of the cell culture. Cellular proliferation and viability were quantified in parallel with direct cell counts and showed no difference between control and Andersen's syndrome patients. Moreover, our data show no significant difference in myoblast fusion index among Andersen's syndrome and control patients. Current recordings carried out on myotubes revealed the absence of an inwardly rectifying Ba2+-sensitive current in affected patient cells. One consequence of the Ik1 current loss in Andersen's syndrome myotubes is a shift of the resting membrane potential toward depolarizing potentials. Our data describe for the first time the functional consequences of Andersen's syndrome mutations ex vivo and provide clues to the K+ channel pathophysiology in skeletal muscle. Andersen's syndrome is a clinically distinct form of potassium-sensitive periodic paralysis associated with cardiac dysrhythmias. The subtle nature of the cardiac and dysmorphic features may delay the recognition of this syndrome and its potentially lethal cardiac dysrhythmias. The genetic defect in Andersen's syndrome is not genetically linked to other forms of potassium-sensitive periodic paralysis and is probably distinct from the long QT syndrome locus. Andersen Tawil syndrome is a rare type of channelopathy characterized by the presence of periodic paralysis, cardiac arrhythmia (prolonged QT interval or ventricular arrhythmia) and distinct dysmorphic abnormalities. It is a type of potassium channelopathy that occurs sporadically or by autosomal dominant inheritance. We report a 14 year old boy with Andersen-Tawil syndrome. Andersen-Tawil syndrome (ATS) is a multisystem inherited disease exhibiting periodic paralysis, cardiac arrhythmias, and dysmorphic features. In this study, we characterized the KCNJ2 channels with an ATS mutation (T75M) which is associated with cardiac phenotypes of bi-directional ventricular tachycardia, syncope, and QT(c) prolongation. Confocal imaging of GFP-KCNJ2 fusion proteins showed that the T75M mutation impaired membrane localization of the channel protein, which was restored by co-expression of WT channels with T75M channels. Whole-cell patch-clamp experiments in CHO-K1 cells showed that the T75M mutation produced a loss-of-function of the channel. When both WT and the T75M were co-expressed, the T75M mutation showed dominant-negative effects on inward rectifier K+ current densities, with prominent suppression of outward currents at potentials between 0 mV and +80 mV over the E(K). Inside-out patch experiments in HEK293T cells revealed that co-expression of WT and the T75M channels enhanced voltage-dependent block of the channels by internal Mg2+, resulting in enhanced inward rectification at potentials 50 mV more positive than the E(K). We suggest that the T75M mutation causes dominant-negative suppression of the co-expressed WT KCNJ2 channels. In addition, the T75M mutation caused alteration of gating kinetics of the mutated KCNJ2 channels, i.e., increased sensitivity to intracellular Mg2+ and resultant enhancement of inward rectification. The data presented suggest that the mutation may influence clinical features, but it does not directly show this. Andersen-Tawil syndrome (ATS) is characterized by ventricular arrhythmias, hypokalemic periodic paralysis and developmental anomalies. It is caused by mutations in the KCNJ2 gene that encodes for the alpha-subunit of Kir2.1, a K(+) channel responsible for cardiac repolarization. Providing effective therapy to reduce arrhythmia burden and risk of sudden death is challenging, especially in the context of pregnancy and childbirth. We report a case of a pregnant 27-year-old woman with an R218W mutation in the C-terminal interaction domain of KCNJ2 causing ATS. Regular cardiac and obstetric assessments were performed for the duration of the pregnancy, which carried to term and delivered successfully with potassium replacement and intravenous beta blockade. ATS is a rare and potentially lethal condition in which there is considerable genetic and phenotypic heterogeneity. Effective management strategies are directed at reducing symptoms, arrhythmia burden and sudden cardiac death. This case illustrates the challenges and approach to management of patients with ATS who are pregnant and undergo childbirth. Andersen cardiodysrhythmic periodic paralysis or Andersen-Tawil syndrome includes the distinct clinical features of periodic paralysis, cardiac arrhythmia, and facial and skeletal dysmorphisms and exhibits autosomal dominant inheritance. Mutations in the KCNJ2 gene, which encodes the human inward rectifier potassium channel Kir2.1, have been identified in the majority of cases. Despite well-established clinical and molecular characteristics, treatment is still case oriented, and timely diagnosis could be delayed because of the low incidence and phenotypic heterogeneity of this disease. This article describes the clinical and molecular features of 3 cases of Andersen-Tawil syndrome in 2 families. One of the mutations (G144D) was located in the pore selectivity filter residue (which is mutated recurrently) and was considered novel. Intermittent muscle weakness in childhood warrants careful evaluation of cardiac dysrhythmia and skeletal anomalies. Andersen-Tawil syndrome (ATS) is characterized by dysmorphic features, periodic paralyses and abnormal ventricular repolarization. After genotyping a large set of patients with congenital long-QT syndrome, we identified two novel, heterozygous KCNJ2 mutations (p.N318S, p.W322C) located in the C-terminus of the Kir2.1 subunit. These mutations have a different localization than classical ATS mutations which are mostly located at a potential interaction face with the slide helix or at the interface between the C-termini. Mutation carriers were without the key features of ATS, causing an isolated cardiac phenotype. While the N318S mutants regularly reached the plasma membrane, W322C mutants primarily resided in late endosomes. Co-expression of N318S or W322C with wild-type Kir2.1 reduced current amplitudes only by 20-25 %. This mild loss-of-function for the heteromeric channels resulted from defective channel trafficking (W322C) or gating (N318S). Strikingly, and in contrast to the majority of ATS mutations, neither mutant caused a dominant-negative suppression of wild-type Kir2.1, Kir2.2 and Kir2.3 currents. Thus, a mild reduction of native Kir2.x currents by non dominant-negative mutants may cause ATS with an isolated cardiac phenotype. BACKGROUND: Mutations of KCNJ2, the gene encoding the human inward rectifier potassium channel Kir2.1, cause Andersen-Tawil syndrome (ATS), a disease exhibiting ventricular arrhythmia, periodic paralysis, and dysmorphic features. However, some KCNJ2 mutation carriers lack the ATS triad and sometimes share the phenotype of catecholaminergic polymorphic ventricular tachycardia (CPVT). We investigated clinical and biophysical characteristics of KCNJ2 mutation carriers with "atypical ATS." METHODS AND RESULTS: Mutational analyses of KCNJ2 were performed in 57 unrelated probands showing typical (≥2 ATS features) and atypical (only 1 of the ATS features or CPVT) ATS. We identified 24 mutation carriers. Mutation-positive rates were 75% (15/20) in typical ATS, 71% (5/7) in cardiac phenotype alone, 100% (2/2) in periodic paralysis, and 7% (2/28) in CPVT. We divided all carriers (n=45, including family members) into 2 groups: typical ATS (A) (n=21, 47%) and atypical phenotype (B) (n=24, 53%). Patients in (A) had a longer QUc interval [(A): 695 ± 52 versus (B): 643 ± 35 ms] and higher U-wave amplitude (0.24 ± 0.07 versus 0.18 ± 0.08 mV). C-terminal mutations were more frequent in (A) (85% versus 38%, P<0.05). There were no significant differences in incidences of ventricular tachyarrhythmias. Functional analyses of 4 mutations found in (B) revealed that R82Q, R82W, and G144D exerted strong dominant negative suppression (current reduction by 95%, 97%, and 96%, respectively, versus WT at -50 mV) and T305S moderate suppression (reduction by 89%). CONCLUSIONS: KCNJ2 gene screening in atypical ATS phenotypes is of clinical importance because more than half of mutation carriers express atypical phenotypes, despite their arrhythmia severity. Evaluation of candidate loci culminated in the identification of a heterozygous missense mutation (R67W) in KCNJ2, the gene encoding the inward-rectifying potassium current, Kir2.1, in 41 members of a kindred in which ventricular arrhythmias (13 of 16 female members [81%]) and periodic paralysis (10 of 25 male members [40%]) segregated as autosomal dominant traits with sex-specific variable expressivity. Some mutation carriers exhibited dysmorphic features, including hypertelorism, small mandible, syndactyly, clinodactyly, cleft palate, and scoliosis, which, together with cardiodysrhythmic periodic paralysis, have been termed "Andersen syndrome." However, no individual exhibited all manifestations of Andersen syndrome, and this diagnosis was not considered in the proband until other family members were examined. Other features seen in this kindred included unilateral dysplastic kidney and cardiovascular malformation (i.e., bicuspid aortic valve, bicuspid aortic valve with coarctation of the aorta, or valvular pulmonary stenosis), which have not been previously associated. Nonspecific electrocardiographic abnormalities were identified in some individuals, but none had a prolonged QT interval. Biophysical characterization of R67W demonstrated loss of function and a dominant-negative effect on Kir2.1 current. These findings support the suggestion that, in addition to its recognized role in function of cardiac and skeletal muscle, KCNJ2 plays an important role in developmental signaling. BACKGROUND: Andersen-Tawil syndrome (ATS) is a rare inherited disorder, characterised by periodic paralysis, cardiac dysarrhythmias, and dysmorphic features, and is caused by mutations in the gene KCNJ2, which encodes the inward rectifier potassium channel, Kir2.1. This study sought to analyse KCNJ2 in patients with familial ATS and to determine the functional characteristics of the mutated gene. METHODS AND RESULTS: We screened a family with inherited ATS for the mutation in KCNJ2, using direct DNA sequencing. A missense mutation (T75R) of Kir2.1, located in the highly conserved cytoplasmic N-terminal domain, was identified in three affected members of this family. Using the Xenopus oocyte expression system and whole cell voltage clamp analyses, we found that the T75R mutant was non-functional and possessed a strong dominant negative effect when co-expressed with the same amount of wild type Kir2.1. Transgenic (Tg) mice expressing the mutated form of Kir2.1 in the heart had prolonged QTc intervals compared with mice expressing the wild type protein. Ventricular tachyarrhythmias were observed in 5 of 14 T75R-Tg mice compared with 1 of 7 Wt-Tg and none of 6 non-transgenic littermates. In three of five T75R-Tg mice with ventricular tachycardia, their ECG disclosed bidirectional tachycardia as in our proband. CONCLUSIONS: The in vitro studies revealed that the T75R mutant of Kir2.1 had a strong dominant negative effect in the Xenopus oocyte expression system. It still preserved the ability to co-assemble and traffic to the cell membrane in mammalian cells. For in vivo studies, the T75R-Tg mice had bidirectional ventricular tachycardia after induction and longer QT intervals. |
385 | How are induced pluripotent stem cells used in the study and treatment of cardiovascular diseases? | The major goal within the field of cardiovascular regenerative medicine is to replace lost or damaged cardiac muscle and coronaries following ischaemic disease. At present, de novo cardiomyocytes can be generated either in vitro, using directed differentiation of embryonic stem cells or induced pluripotent stem cells, or in vivo via direct reprogramming of resident adult cardiac fibroblast or ectopic stimulation of resident cardiac stem or progenitor cells. The production of human cardiac progenitor cells and cardiomyocytes from human pluripotent stem cells provides an amenable source of cells for applications in drug discovery, disease modeling, regenerative medicine, and cardiotoxicity screening. In addition, the ability to derive human-induced pluripotent stem cells from somatic tissues, combined with current high-throughput screening and pharmacogenomics, may help realize the use of these cells to fulfill the potential of personalized medicine. Human induced pluripotent stem cells (iPSC) provide a unique opportunity to study "disease in a dish" within a defined genetic and environmental background. Patient-derived iPSCs have been successfully used to model cardiomyopathies, rhythm disorders and vascular disorders. Long-QT syndrome and catecholaminergic polymorphic ventricular tachycardia are two heart rhythm disorders that have been already successfully modeled by several groups using this approach, which will likely serve to model other mono- or polygenetic cardiovascular disorders in the future. The use of iPSC-derived cardiomyocytes to study genetic cardiovascular disorders will enable a deeper and more applicable understanding of the molecular mechanisms of human disease, as well as improving our ability to achieve successful cell-based therapies. | [21527744, 23292032, 21919874, 23390563, 24298311, 22917225, 23955788, 23819949, 22447279, 21451408, 21569778, 23229562, 23896987, 22385148] | 492 | The successful derivation of human induced pluripotent stem cells (hiPSCs) by dedifferentiation of somatic cells offers significant potential to overcome obstacles in the field of cardiovascular disease. hiPSC derivatives offer incredible potential for new disease models and regenerative medicine therapies. However, many questions remain regarding the optimal starting materials and methods to enable safe, efficient derivation of hiPSCs suitable for clinical applications. Initial reprogramming experiments were carried out using lentiviral or retroviral gene delivery methods. More recently, various nonviral methods that avoid permanent and random transgene insertion have emerged as alternatives. These include transient DNA transfection using plasmids or minicircles, protein transduction, or RNA transfection. In addition, several small molecules have been found to significantly augment hiPSC derivation efficiency, allowing the use of a fewer number of genes during pluripotency induction. We review these various methods for the derivation of hiPSCs, focusing on their ultimate clinical applicability, with an emphasis on their potential for use as cardiovascular therapies and disease-modeling platforms. Cardiovascular disease remains the leading cause of morbidity and mortality in the developed countries. This review summarizes current pre-clinical and clinical evidence for the potential role and mechanisms of action of stem and progenitor cells in vascular and cardiac repair and regeneration. Apart from cell transplantation strategies, approaches to maintain stem cell niche function and targeting mobilization/recruitment of specific stem/progenitor cell populations may aid in preserving vascular and cardiac function. Moreover, with the use of patient-derived induced pluripotent stem cells, the field of regenerative medicine is entering a new era. Potential applications of induced pluripotent stem cells and direct reprogrammed cells as well as recent developments in tissue engineering are discussed. Human induced pluripotent stem cell-derived endothelial cells (hiPSC-ECs) are promising for treatment of vascular diseases. However, hiPSC-ECs purified based on CD31 expression are comprised of arterial, venous, and lymphatic subtypes. It is unclear whether hiPSC-ECs are heterogeneous in nature, and whether there may be functional benefits of enriching for specific subtypes. Therefore, we sought to characterize the hiPSC-ECs and enrich for each subtype, and demonstrate whether such enrichment would have functional significance. The hiPSC-ECs were generated from differentiation of hiPSCs using vascular endothelial growth factor (VEGF)-A and bone morphogenetic protein-4. The hiPSC-ECs were purified based on positive expression of CD31. Subsequently, we sought to enrich for each subtype. Arterial hiPSC-ECs were induced using higher concentrations of VEGF-A and 8-bromoadenosine-3':5'-cyclic monophosphate in the media, whereas lower concentrations of VEGF-A favored venous subtype. VEGF-C and angiopoietin-1 promoted the expression of lymphatic phenotype. Upon FACS purification based on CD31+ expression, the hiPSC-EC population was observed to display typical endothelial surface markers and functions. However, the hiPSC-EC population was heterogeneous in that they displayed arterial, venous, and to a lesser degree, lymphatic lineage markers. Upon comparing vascular formation in matrigel plugs in vivo, we observed that arterial enriched hiPSC-ECs formed a more extensive capillary network in this model, by comparison to a heterogeneous population of hiPSC-ECs. This study demonstrates that FACS purification of CD31+ hiPSC-ECs produces a diverse population of ECs. Refining the differentiation methods can enrich for subtype-specific hiPSC-ECs with functional benefits of enhancing neovascularization. Induced pluripotent stem cells (iPSCs) can be generated from adult somatic tissues by the forced expression of a few defined transcription factors, including Oct4, Sox2, Klf4, and c-Myc. iPSC technology holds tremendous promises for therapeutic cardiovascular regeneration because of the cells' unlimited capacity for proliferation and differentiation into all cell lineages. The iPSCs can be generated from somatic cells of patients with a genetic basis for their disease so as to understand the pathobiology of the disorder. This disease modeling can be adapted to high-throughput screens to discover new therapeutic molecules. Finally, the iPSC technology may enable personalized cell therapies, while avoiding the ethical concerns surrounding human embryonic stem cells. Intensive efforts are underway to develop reliable methods to guide stem cell differentiation into cardiovascular lineages in the treatment of peripheral artery disease and heart diseases. Studies of disease pathogenesis and drug discovery using iPSC technology shall advance the discovery of novel treatments for cardiovascular diseases. The discovery that somatic cells can be reprogrammed to induced pluripotent stem cells (iPSC) by overexpression of a combination of transcription factors bears the potential to spawn a wealth of new applications in both preclinical and clinical cardiovascular research. Disease modeling, which is accomplished by deriving iPSC lines from patients affected by heritable diseases and then studying the pathophysiology of the diseases in somatic cells differentiated from these patient-specific iPSC lines, is the so far most advanced of these applications. Long-QT syndrome and catecholaminergic polymorphic ventricular tachycardia are two heart rhythm disorders that have been already successfully modeled by several groups using this approach, which will likely serve to model other mono- or polygenetic cardiovascular disorders in the future. Test systems based on cells derived from iPSC might prove beneficial to screen for novel cardiovascular drugs or unwanted drug side effects and to individualize medical therapy. The application of iPSC for cell therapy of cardiovascular disorders, albeit promising, will only become feasible if the problem of biological safety of these cells will be mastered. PURPOSE OF REVIEW: The development of induced pluripotent stem cell (iPSC) technology has led to many advances in the areas of directed cell differentiation and characterization. New methods for generating iPSC-derived cardiomyocytes provide an invaluable resource for the study of certain cardiovascular disorders. This review highlights the current technology in this field, its application thus far to the study of genetic disorders of the RAS/MAPK pathway and long-QT syndrome (LQTS), and future directions for the field. RECENT FINDINGS: Enhanced methods increase the efficiency of generating and stringently purifying iPSC-derived cardiomyocytes. The use of cardiomyocytes derived from patients with LEOPARD syndrome and LQTS has shed light on the molecular mechanisms of disease and validated their use as reliable human disease models. SUMMARY: The use of iPSC-derived cardiomyocytes to study genetic cardiovascular disorders will enable a deeper and more applicable understanding of the molecular mechanisms of human disease, as well as improving our ability to achieve successful cell-based therapies. Methods to efficiently generate these cells are improving and provide promise for future applications of this technology. Human induced pluripotent stem (iPS) cells potentially provide a unique resource for generating patient-specific cardiomyocytes to study cardiac disease mechanisms and treatments. However, existing approaches to cardiomyocyte production from human iPS cells are inefficient, limiting the application of iPS cells in basic and translational cardiac research. Furthermore, strategies to accurately record changes in iPS cell-derived cardiomyocyte action potential duration (APD) are needed to monitor APD-related cardiac disease and for rapid drug screening. We examined whether modulation of the bone morphogenetic protein 4 (BMP-4) and Wnt/β-catenin signaling pathways could induce efficient cardiac differentiation of human iPS cells. We found that early treatment of human iPS cells with BMP-4 followed by late treatment with small molecule Wnt inhibitors led to a marked increase in production of cardiomyocytes compared to existing differentiation strategies. Using immunocytochemical staining and real-time intracellular calcium imaging, we showed that these induced cardiomyocytes expressed typical sarcomeric markers, exhibited normal rhythmic Ca(2+) transients, and responded to both β-adrenergic and electric stimulation. Furthermore, human iPS cell-derived cardiomyocytes demonstrated characteristic changes in action potential duration in response to cardioactive drugs procainamide and verapamil using voltage-sensitive dye-based optical recording. Thus, modulation of the BMP-4 and Wnt signaling pathways in human iPS cells leads to highly efficient production of cardiomyocytes with typical electrophysiological function and pharmacologic responsiveness. The use of human iPS cell-derived cardiomyocytes and the application of calcium- and voltage-sensitive dyes for the direct, rapid measurement of iPS cell-derived cardiomyocyte activity promise to offer attractive platforms for studying cardiac disease mechanisms and therapeutics. Drug attrition rates have increased in past years, resulting in growing costs for the pharmaceutical industry and consumers. The reasons for this include the lack of in vitro models that correlate with clinical results and poor preclinical toxicity screening assays. The in vitro production of human cardiac progenitor cells and cardiomyocytes from human pluripotent stem cells provides an amenable source of cells for applications in drug discovery, disease modeling, regenerative medicine, and cardiotoxicity screening. In addition, the ability to derive human-induced pluripotent stem cells from somatic tissues, combined with current high-throughput screening and pharmacogenomics, may help realize the use of these cells to fulfill the potential of personalized medicine. In this review, we discuss the use of pluripotent stem cell-derived cardiomyocytes for drug discovery and cardiotoxicity screening, as well as current hurdles that must be overcome for wider clinical applications of this promising approach. Cardiovascular progenitor cells (CVPCs) derived from human pluripotent stem cells (hPSCs), including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), hold great promise for the study of cardiovascular development and cell-based therapy of heart diseases, but their applications are challenged by the difficulties in their efficient generation and stable maintenance. This study aims to develop chemically defined systems for robust generation and stable propagation of hPSC-derived CVPCs by modulating the key early developmental pathways involved in human cardiovascular specification and CVPC self-renewal. Herein we report that a combination of bone morphogenetic protein 4 (BMP4), glycogen synthase kinase 3 (GSK3) inhibitor CHIR99021 and ascorbic acid is sufficient to rapidly convert monolayer-cultured hPSCs, including hESCs and hiPSCs, into homogeneous CVPCs in a chemically defined medium under feeder- and serum-free culture conditions. These CVPCs stably self-renewed under feeder- and serum-free conditions and expanded over 10(7)-fold when the differentiation-inducing signals from BMP, GSK3 and Activin/Nodal pathways were simultaneously eliminated. Furthermore, these CVPCs exhibited expected genome-wide molecular features of CVPCs, retained potentials to generate major cardiovascular lineages including cardiomyocytes, smooth muscle cells and endothelial cells in vitro, and were non-tumorigenic in vivo. Altogether, the established systems reported here permit efficient generation and stable maintenance of hPSC-derived CVPCs, which represent a powerful tool to study early embryonic cardiovascular development and provide a potentially safe source of cells for myocardial regenerative medicine. |
386 | Which disease is included as an additional feature in the Goldberg-Shprintzen syndrome? | Shprintzen-Goldberg syndrome (SGS) is characterized by: craniosynostosis of the coronal, sagittal, or lambdoid sutures; dolichocephaly; distinctive craniofacial features; skeletal changes (dolichostenomelia, arachnodactyly, camptodactyly, pes planus, pectus excavatum or carinatum, scoliosis, joint hypermobility or contractures and C1/C2 spine malformation); neurologic abnormalities; intellectual disability; and brain anomalies (hydrocephalus, dilatation of the lateral ventricles, and Chiari 1 malformation). Cardiovascular anomalies may include mitral valve prolapse, mitral regurgitation/incompetence, aortic regurgitation and aortic root dilatation. Minimal subcutaneous fat, abdominal wall defects, myopia, and cryptorchidism in males, are also characteristic findings.Shprintzen-Goldberg syndrome (SGS) is characterized by craniosynostosis and marfanoid habitus. | [16970241, 7573130, 7573131, 15884042, 20301454, 9508238, 10874640, 9130129, 12846610, 15883926, 20621975, 18192286, 1785632, 16760737, 8563763, 7605558, 23984569, 21307714, 17979970, 23427148, 9571278, 22639450, 17303258, 12878302, 8929375, 23023332] | 493 | Shprintzen-Goldberg syndrome is a rare connective tissue disorder characterized by marfanoid habitus and additional dysmorphic stigmata. Craniocervical anomalies occur in fewer than 30% of cases. Serious vertebral instability can also occur, albeit rarely. The authors report on the first patient treated with surgical fusion at the craniocervical junction because of a C-1 dysplasia and severe instability. The skeletal and cardiovascular anomalies that can pose additional problems for surgical treatment and perioperative care are discussed in detail. The Shprintzen-Goldberg syndrome (SGS) is a disorder of unknown cause comprising craniosynostosis, a marfanoid habitus and skeletal, neurological, cardiovascular, and connective-tissue anomalies. There are no pathognomonic signs of SGS and diagnosis depends on recognition of a characteristic combination of anomalies. Here, we describe 14 persons with SGS and compare their clinical findings with those of 23 previously reported individuals, including two families with more than one affected individual. Our analysis suggests that there is a characteristic facial appearance, with more than two thirds of all individuals having hypertelorism, down-slanting palpebral fissures, a high-arched palate, micrognathia, and apparently low-set and posteriorly rotated ears. Other commonly reported manifestations include hypotonia in at least the neonatal period, developmental delay, and inguinal or umbilical hernia. The degree of reported intellectual impairment ranges from mild to severe. The most common skeletal manifestations in SGS were arachnodactyly, pectus deformity, camptodactyly, scoliosis, and joint hypermobility. None of the skeletal signs alone is specific for SGS. Our study includes 14 mainly German individuals with SGS evaluated over a period of 10 years. Given that only 23 other persons with SGS have been reported to date worldwide, we suggest that SGS may be more common than previously assumed. Shprintzen-Goldberg syndrome is one of a group of disorders characterized by craniosynostosis and marfanoid habitus. Eleven cases were reported previously. We present 4 new patients and review one of the patients of the original report of Shprintzen and Goldberg [1982: J Craniofac Genet Dev Biol 2:65-74], 15 years later. The clinical and radiologic findings on our patients are compared with those of the previously reported patients and also with those of Furlong et al. [1987: Am J Med Genet 26:599-604] and Lacombe and Battin [1993: Clin Dysmorphol 2: 220-224], who share many of the characteristics of Shprintzen-Goldberg syndrome. Some of the clinical data are helpful in determining if the patients of Furlong et al. [1987: Am J Med Genet 26:599-604] and Lacombe and Battin [1993: Clin Dysmorphol 2: 220-224] have a separate syndrome or represent a variant of Shprintzen-Goldberg syndrome. However, radiologic investigations appear to be more specific, since an abnormality of the first and second cervical vertebrae, hydrocephalus, dilatation of the lateral ventricles, and a Chiari-I malformation of the brain were found only in the patients with Shprintzen-Goldberg syndrome. The apparently diagnostic findings of the 15 patients with this syndrome may be helpful in differentiating between Shprintzen-Goldberg syndrome and other syndromes with craniosynostosis and marfanoid habitus. Annuloaortic ectasia due to Shprintzen-Goldberg syndrome (SGS) is reported. A 10-year-old boy was admitted to our hospital for evaluation of chest pain. On admission, he was diagnosed as SGS on the basis of his various anomalies. Two-dimensional echocardiography showed a bicuspid aortic valve and marked annular dilatation, Doppler flow studies revealed severe aortic regurgitation, and retrograde aortography showed severe aortic regurgitation with annular dilatation. Successful aortic root replacement was performed; subsequent histologic examination of the ascending aorta demonstrated cystic medial necrosis. In conclusion, SGS is a generalized connective tissue dysplasia, with clinical manifestations of cardiovascular lesions similar to those in Marfan syndrome. Aortic root replacement was successfully performed; however, recurrence of aortic aneurysms outside of the ascending aorta should be carefully observed. Surgical treatment for cardiovascular disorders may be necessary to save the life of patients with SGS. The Shprintzen-Goldberg syndrome is an extremely rare syndrome with a characteristic face. This is one of a group of disorders characterized by craniosynostosis and marfanoid features. The aim of this study was to present a new sporadic case of the syndrome and describe in detail the findings at the maxillofacial region. We identified, by homozygosity mapping, a novel locus on 10q21.3-q22.1 for Goldberg-Shprintzen syndrome (GOSHS) in a consanguineous Moroccan family. Phenotypic features of GOSHS in this inbred family included microcephaly and mental retardation, which are both central nervous system defects, as well as Hirschsprung disease, an enteric nervous system defect. Furthermore, since bilateral generalized polymicogyria was diagnosed in all patients in this family, this feature might also be considered a key feature of the syndrome. We demonstrate that homozygous nonsense mutations in KIAA1279 at 10q22.1, encoding a protein with two tetratrico peptide repeats, underlie this syndromic form of Hirschsprung disease and generalized polymicrogyria, establishing the importance of KIAA1279 in both enteric and central nervous system development. Goldberg-Shprintzen syndrome (GOSHS) is a rare clinical disorder characterized by central and enteric nervous system defects. This syndrome is caused by inactivating mutations in the Kinesin Binding Protein (KBP) gene, which encodes a protein of which the precise function is largely unclear. We show that KBP expression is up-regulated during neuronal development in mouse cortical neurons. Moreover, KBP-depleted PC12 cells were defective in nerve growth factor-induced differentiation and neurite outgrowth, suggesting that KBP is required for cell differentiation and neurite development. To identify KBP interacting proteins, we performed a yeast two-hybrid screen and found that KBP binds almost exclusively to microtubule associated or related proteins, specifically SCG10 and several kinesins. We confirmed these results by validating KBP interaction with one of these proteins: SCG10, a microtubule destabilizing protein. Zebrafish studies further demonstrated an epistatic interaction between KBP and SCG10 in vivo. To investigate the possibility of direct interaction between KBP and microtubules, we undertook co-localization and in vitro binding assays, but found no evidence of direct binding. Thus, our data indicate that KBP is involved in neuronal differentiation and that the central and enteric nervous system defects seen in GOSHS are likely caused by microtubule-related defects. We describe a brother and sister with Hirschsprung disease, hypotonia, and ptosis. Their condition resembles that in 2 sibs reported by Goldberg and Shprintzen. We conclude that the clinical characteristics in 8 reported cases with similar clinical manifestations represent a distinct autosomal recessive syndrome, Goldberg-Shprintzen syndrome. Recent reports have described a distinct and recurrent pattern of systemic malformation that associates craniosynostosis and neurodevelopmental abnormalities with many clinical features of the Marfan syndrome (MFS), an autosomal dominant disorder of the extracellular microfibril caused by defects in the gene encoding fibrillin-1, FBN1 (ref. 8). Additional common findings include other craniofacial anomalies, hypotonia, obstructive apnea, foot deformity, and congenital weakness of the abdominal wall. So far, only 11 cases have been reported precluding the assignment of definitive diagnostic criteria. While it remains unclear whether these cases represent a discrete clinical entity with a single aetiology, they have been pragmatically grouped under the rubric Marfanoid-craniosynostosis or Shprintzen-Goldberg syndrome (SGS). Because of the significant clinical overlap between MFS and SGS, we proposed that they may be caused by allelic mutations. We now report two SGS patients who harbour mutations in FBN1. While it remains unclear whether these mutations are sufficient for the clinical expression of the entire SGS phenotype, these data suggest a role for fibrillin-1 in early craniofacial and central nervous system development. Our recent observation that FBN1 transcript is expressed as early as the 8-cell stage of human embryogenesis is consistent with this hypothesis. A 5-year-old girl with Hirschsprung disease, unusual facial appearance, psychomotor retardation, epilepsy, and congenital heart disease is reported. Patients with similar clinical features have been reported and they appear to exhibit the recently identified Goldberg-Shprintzen syndrome. It is believed that this girl also exhibits this new syndrome. Cranial computed tomography demonstrated abnormal findings that may suggest defective neuronal migration and/or dysgenesis of the brain. These findings were considered to cause psychomotor retardation and epilepsy in this patient. BACKGROUND: Shprintzen-Goldberg syndrome (SGS) is characterized by craniosynostosis and marfanoid habitus. The clinical findings of SGS include neurological, cardiovascular, connective tissue, and skeletal abnormalities. Among these skeletal findings, developmental scoliosis is recognized in half of all patients with SGS. However, no earlier reports have described the surgical treatment of scoliosis associated with SGS. METHODS: Four patients (2 boys and 2 girls; mean age at the time of surgery, 7.3±4.4 y) with SGS who underwent surgical treatment for progressive scoliosis were reviewed. The radiologic findings, operative findings, and perioperative complications were evaluated. RESULTS: The mean preoperative Cobb angle was 102.8±16.9 degrees. The curve patterns were a double curve in 2 cases and a triple curve in 2 cases. Local kyphosis at the thoracolumbar area was recognized in all the cases with a mean kyphosis angle of 49±16 degrees. Growing rod procedures were performed in 2 patients, and posterior correction and fusion were performed in 2 patients. The mean correction rate was 45% in the patients who underwent the growing rod procedures at the time of growing rod placement and 51% in the patients who underwent posterior correction and fusion. Dislodgement of the proximal anchors occurred in 3 of the 4 patients. One patient developed pseudoarthrosis. Two patients developed deep wound infections, and implant removal was necessary in 1 patient. CONCLUSIONS: Surgical treatment for scoliosis in patients with SGS was associated with a high incidence of perioperative and postoperative complications including implant dislodgements and deep wound infections attributable to poor bone quality and a thin body habitus, which are characteristic clinical features of this syndrome. Careful preoperative surgical planning and postoperative care are critical for the surgical treatment of scoliosis associated with SGS, especially in infants requiring multiple surgeries. LEVEL OF EVIDENCE: Level IV. Shprintzen-Goldberg syndrome (SGS) is a rare disorder characterized by a Marfan-like habitus, mental retardation and craniosynostosis. Cardiac abnormalities, such as aortic root dilation have also been noted as well as several skeletal abnormalities. Its nosological status is unclear as it is hard to delineate SGS from similar disorders, such as Furlong, Marfan type II, Camurati-Engelmann and Loeys-Dietz syndromes. It has been suggested that these conditions represent a phenotypical spectrum associated with aberrant TGF-beta signalling. In support of this notion, we found a novel TGFBR2 missense mutation in a patient with features of SGS. In 1981, Goldberg and Shprintzen described siblings with short-segment Hirschsprung disease, cleft palate, microcephaly, mild mental retardation, short stature and distinctive facial appearance. There have been several subsequent reports which broaden the phenotype. This paper describes a further family, reviews the literature and stresses the intra-familial variability. OBJECTIVE: Recognition of the phenotypic spectrum and prognosis of a genetic disorder is critical to proper patient care. A 7-year-old boy with Sphrintzen-Goldberg syndrome (SGS) was studied to investigate speech, language and voice patterns associated with this syndrome. METHODS: The child's language (expressive and receptive) and speech was characterized with regard to overall intelligibility, articulation (phonetic and phonological errors), voice (flexible videolaryngostroboscopy, quality, pitch and loudness) and resonance (type of disorders). RESULTS: Based on this detailed study the most striking communication characteristics in this child with SGS appear to be a delayed speech and language onset, an expressive and receptive language disorder, a moderately impaired speech intelligbility, relatively good phonetic but poorer phonological abilities, an oral hypotonia, a high-pitched soft voice and a slight hypernasality. CONCLUSIONS: The explanation for this communication disorder is not completely straightforward. It is not clear either to what extent the present case can be considered as typical for SGS. Only more data will allow to determine whether or not SGS is associated with a typical syndrome specific pattern of communication disorders. Not only detailed speech and language analyses of additional cases of SGS are necessary, but also studies that compare the speech and language of individuals with SGS with that of individuals with other genetic syndrome. Neurocristopathies are a group of diverse disorders resulting from defective growth, differentiation, and migration of the neural crest cells. Hirschsprung's disease, namely aganglionic megacolon, is the consequence of defective migration of neural crest cells on to the colonic submucosa and is therefore considered a neurocristopathy. We report on four children in whom was diagnosed a neurocristopathy, associating Hirschsprung's disease with a wide spectrum of neurologic abnormalities. The patients included two children presenting the phenotypic features of the Goldberg-Shprintzen syndrome: distinct dysmorphic facial features, microcephaly, and mental retardation, along with agenesis of the corpus callosum and cortical malformations associated with intractable seizures in one child. The third newborn presented with the Haddad syndrome: short-segment Hirschsprung's disease associated with the congenital central hypoventilation syndrome requiring permanent artificial ventilation. In the fourth child, absence of the corpus callosum was associated with mild dysmorphic features, borderline cognitive abilities, and attention-deficit disorder. Therefore, awareness of a possible neurocristopathy associated with neurologic abnormalities should be taken into account in any patient newly diagnosed with Hirschsprung's disease to detect the abnormalities early and promptly manage them. A thorough neurologic examination and a developmental assessment, including magnetic resonance imaging of the brain and electroencephalography, should be performed for any child presenting with an aganglionic megacolon, especially those presenting with seizures, developmental delay, or even congenital hypoventilation. We report the case of a Japanese boy whose dysmorphic features were consistent with those of Shprintzen-Goldberg syndrome. The radiological features were characterized by late-onset craniosynostosis, arachnodactyly, undermodeling of short tubular bones, mildly undermodeled and slightly bowed long bones, twisted ribs and tall vertebral bodies with elongated neural arches. Apart from the craniosynostosis, these skeletal changes resembled those of frontometaphyseal dysplasia, a well-known craniotubular dysplasia. Shprintzen-Goldberg syndrome also shares many clinical features with frontometaphyseal dysplasia. Elevated transforming growth factor (TGF)-β signaling has been implicated in the pathogenesis of syndromic presentations of aortic aneurysm, including Marfan syndrome (MFS) and Loeys-Dietz syndrome (LDS). However, the location and character of many of the causal mutations in LDS intuitively imply diminished TGF-β signaling. Taken together, these data have engendered controversy regarding the specific role of TGF-β in disease pathogenesis. Shprintzen-Goldberg syndrome (SGS) has considerable phenotypic overlap with MFS and LDS, including aortic aneurysm. We identified causative variation in ten individuals with SGS in the proto-oncogene SKI, a known repressor of TGF-β activity. Cultured dermal fibroblasts from affected individuals showed enhanced activation of TGF-β signaling cascades and higher expression of TGF-β-responsive genes relative to control cells. Morpholino-induced silencing of SKI paralogs in zebrafish recapitulated abnormalities seen in humans with SGS. These data support the conclusions that increased TGF-β signaling is the mechanism underlying SGS and that high signaling contributes to multiple syndromic presentations of aortic aneurysm. |
387 | Which protein is causing Netherton syndrome? | Netherton syndrome (NS) is a serious inherited skin disorder caused by mutations in the gene SPINK5 (serine protease inhibitor Kazal type 5) which encodes for a serine protease inhibitor LEKTI (lymphoepithelial Kazal type-related inhibitor) | [23407075, 24292773, 24138501, 23347305, 23344365, 24015757, 21895535, 24211642, 20657595, 21697885] | 494 | Netherton syndrome (NS, OMIM 256500) is a rare autosomal recessive disorder manifesting with congenital ichthyosis, a specific hair shaft abnormality named trichorrhexis invaginata, and atopic manifestations. Because of severe complications frequently occurring in the neonatal period, NS prognosis can be poor in infancy. NS is due to loss-of-function mutations in the SPINK5 gene and to the consequent lack of expression of its encoded protein LEKTI in the skin and all stratified epithelial tissues. Following the identification of the NS causative gene and protein, specific diagnostic tools have been developed, thus breaking up the challenge of distinguishing NS from other congenital ichthyoses with overlapping features, and from severe, early-onset forms of atopic dermatitis or psoriasis. Intensive efforts to extend the knowledge into the pathomechanisms of NS have also been made. However, NS management is still problematic due to the lack of specific treatment and unmet needs. This overview summarizes the current state of the art in NS research with an emphasis on the progress made toward disease-specific innovative therapy development. Netherton syndrome (NTS) is a rare genetic skin disease caused by mutations in the serine protease inhibitor Kazal-type 5 gene, which encodes the lympho-epithelial Kazal-type-related inhibitor. NTS patients have profoundly impaired skin barrier function. As stratum corneum (SC) lipids have a crucial role in the skin barrier function, we investigated the SC lipid composition and organization in NTS patients. We studied the SC lipid composition by means of mass spectrometry, and the lipid organization was examined by infrared spectroscopy and X-ray diffraction. Decreased free fatty acid (FFA) chain length and increased levels of monounsaturated FFAs were observed in the SC of NTS patients compared with controls. Furthermore, the level of short-chain ceramides (CERs) was enhanced in NTS patients and a strong reduction in long-chain CER levels was seen in several patients. The changes in lipid composition modified the lipid organization leading to an increased disordering of the lipids compared with the controls. In addition, in a subgroup of patients the organization of the lipid layers changed dramatically. The altered FFA and CER profiles in NTS patients corresponded to changes in the expression of enzymes involved in SC lipid processing. The observed changes in lipid composition, lipid organization, and enzyme expression are likely to contribute to the barrier dysfunction in NTS. Netherton syndrome (NS) is a serious inherited skin disorder caused by mutations in the gene SPINK5 (serine protease inhibitor Kazal type 5) which encodes for a serine protease inhibitor LEKTI (lymphoepithelial Kazal type-related inhibitor). Patients with NS have defective keratinization, hair shaft defects, recurrent infections, atopy and a predisposition to skin malignancies. Historically, one in ten infants has died before their first birthday. Currently there are no proven treatments to cure this condition. A SIN-lentiviral vector encoding the codon optimized SPINK5 gene under the control of a 572bp element derived from the human involucrin promoter (INVO) can confer compartment specific LEKTI expression in NS keratinocytes with restoration of normal skin architecture. Here we detail a study protocol for a phase I trial for feasibility and safety evaluations of autologous epidermal sheets generated from ex-vivo gene corrected keratinocyte stem cells, which will be grafted onto patients with mutation proven NS. OBJECTIVES: Netherton's syndrome (NS) is a rare autosomal recessive condition, first described in 1958, which involves a complex immunological dysfunction, ichthyosiform dermatitis, and erythroderma, characteristic defects of the hair shaft and atopy. Recurrent bacterial infection in the skin of patients with NS is frequent. METHODS: This paper represents the first case report of leprosy and concurrent NS. DISCUSSION: This case merits discussion among doctors in endemic and non-endemic areas to evaluate the chronic use of systemic corticosteroids as a risk factor for leprosy. The present patient came from an endemic area of leprosy and was treated chronically with systemic corticosteroids for erythroderma. This treatment, along with the immunodeficiency related to the syndrome and caused by a genetic mutation in SPINK5, may be a facilitating factor for the infection. Netherton syndrome (NS) is a rare autosomal recessive skin disease with severe skin inflammation and scaling, a specific hair shaft defect and constant allergic manifestations. NS is caused by loss-of-function mutations in SPINK5 (serine protease inhibitor of kazal type 5) encoding LEKTI-1 (lympho-epithelial kazal type related inhibitor type 5) expressed in stratified epithelia. In vitro and in vivo studies in murine models and in NS patients have cast light on the pathogenesis of the disease and shown that LEKTI deficiency results in unopposed kallikrein-related peptidase 5 (KLK5) and KLK7 activities and to the overactivity of a new epidermal protease, elastase 2 (ELA2). Two main cascades initiated by KLK5 activity have emerged. One results in desmoglein 1 degradation and desmosome cleavage leading to stratum corneum detachment. KLK5 also activates KLK7 and ELA2, which contribute to a defective skin barrier. This facilitates allergen and microbe penetration and generates danger signals leading to caspase 1 activation and the production of active interleukin-1β. In parallel, KLK5 activates a specific cascade of allergy and inflammation by activating protease-activated receptor-2 (PAR-2) receptors. PAR-2 activation triggers the production of the major pro-Th2 cytokine TSLP (thymic stromal lymphopoietin) and several inflammatory cytokines, including tumour necrosis factor-α. Levels of thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) also contribute to allergy in a PAR-2-independent manner. Patient investigations have confirmed these abnormalities and revealed a wide spectrum of disease expression, sometimes associated with residual LEKTI expression. These results have demonstrated that the tight regulation of epidermal protease activity is essential for skin homeostasis and identified new targets for therapeutic intervention. They also provide a link with atopic dermatitis through deregulated protease activity, as recently supported by functional studies of the E420K LEKTI variant. Netherton syndrome (NS) is a rare autosomal recessive disorder characterized by ichthyosiform scaling, hair abnormalities, and variable atopic features. Mutations in the serine protease inhibitor Kazal type 5 (SPINK5) gene leading to lymphoepithelial Kazal-type-related inhibitor (LEKTI) deficiency cause NS. Growth retardation is a classic feature of NS, but growth hormone (GH) deficiency with subsequent response to GH therapy is not documented in the literature. It is proposed that a lack of inhibition of proteases due to a deficiency of LEKTI in the pituitary gland leads to the overprocessing of human GH in NS. Herein we report three patients with NS who had growth retardation associated with GH deficiency and responded well to GH therapy. Gene-modified skin grafts, produced through gene transfer to human keratinocyte stem cells, offer the possibility of therapeutic benefit for inherited skin diseases. We have previously described efficient lentiviral vector-mediated gene transfer to keratinocyte stem cells and the generation of human skin grafts for the inherited skin disease, Netherton syndrome, which arises due to mutations in serine protease inhibitor Kazal-type 5 (SPINK5). Vectors incorporating an internal murine retroviral-derived promoter [spleen focus-forming virus (SFFV)] in combination with a codon-optimized SPINK5 transgene supported high levels of reconstitution and robust correction of skin architecture. Subsequent longer-term experiments have uncovered unanticipated silencing phenomena, with loss of SPINK5 gene expression over time. The inadvertent introduction of CpG sites during codon optimization appears to have rendered vectors susceptible to silencing due to methylation across the promoter-transgene boundary. Substitution of the methylation-susceptible SFFV promoter with a 572-bp minimal human involucrin promoter (INVOp), which encodes very few CpG sites, prevented repression of the SPINK5 transgene and resulted in durable and highly compartment-specific reconstitution of lympho-epithelial Kazal-type-related inhibitor (LEKTI) in human skin grafted onto immunodeficient mice. We conclude that skin grafts modified with lentiviral vectors encoding INVOp offer a suitable platform for therapeutic gene therapy in Netherton syndrome, and our experience highlights unanticipated effects of transgene codon optimization. Deficiency in the serine protease inhibitor LEKTI is the etiological origin of Netherton syndrome, which causes detachment of the stratum corneum and chronic inflammation. Here we show that the membrane protease matriptase initiates Netherton syndrome in a LEKTI-deficient mouse model by premature activation of a pro-kallikrein cascade. Auto-activation of pro-inflammatory pro-kallikrein-related peptidases that are associated with stratum corneum detachment was either low or undetectable, but they were efficiently activated by matriptase. Ablation of matriptase from LEKTI-deficient mice dampened inflammation, eliminated aberrant protease activity, prevented detachment of the stratum corneum, and improved the barrier function of the epidermis. These results uncover a pathogenic matriptase-pro-kallikrein pathway that could operate in several human skin and inflammatory diseases. Lympho-epithelial Kazal-type-related inhibitor (LEKTI) is the defective protein of the ichthyosiform condition Netherton syndrome (NS). Strongly expressed in the most differentiated epidermal layers, LEKTI is a serine protease inhibitor synthesized as three different high-molecular-weight precursors, which are rapidly processed into shorter fragments and secreted extracellularly. LEKTI polypeptides interact with several proteases to regulate skin barrier homeostasis as well as inflammatory and/or immunoallergic responses. Here, by combining antibody mapping, N-terminal sequencing, and site-specific mutagenesis, we defined the amino-acid sequence of most of the LEKTI polypeptides physiologically generated in human epidermis. We also identified three processing intermediates not described so far. Hence, a proteolytic cascade model for LEKTI activation is proposed. We then pinpointed the most effective fragments against the desquamation-related kallikreins (KLKs) and we proved that LEKTI is involved in stratum corneum shedding as some of its polypeptides inhibit the KLK-mediated proteolysis of desmoglein-1. Finally, we quantified the individual LEKTI fragments in the uppermost epidermis, showing that the ratios between LEKTI polypeptides and active KLK5 are compatible with a fine-tuned inhibition. These findings are relevant both to the understanding of skin homeostasis regulation and to the design of novel therapeutic strategies for NS. |
388 | Mutations in which gene and which protein are associated with Netherton syndrome? | NS is due to loss-of-function mutations in the SPINK5 gene and to the consequent lack of expression of its encoded protein LEKTI in the skin and all stratified epithelial tissues. | [20877344, 23407075, 10835624, 16307658, 19438860, 24015757, 22377713, 21255986, 16225619, 11841556, 15304086, 17608759, 21251800, 16796630, 11511292, 17989726] | 495 | Netherton syndrome (NS) is a debilitating congenital skin disorder caused by mutations in the SPINK5 gene encoding the lymphoepithelial Kazal-type-related inhibitor (LEKTI). It is characterized by defective keratinization, recurrent infections, and hypernatraemic dehydration with a mortality rate of about 10% in the first year of life. Currently, there are no curative treatments for NS. We have developed a HIV-1 based, self-inactivating lentiviral vector to express SPINK5 in keratinocytes as part of an ex-vivo gene therapy strategy for NS. High transduction efficiency was achieved in NS keratinocytes and reconstitution of LEKTI expression was confirmed in previously deficient cells. These genetically corrected keratinocytes were further tested in an in vitro organotypic culture (OTC) system and in vivo mouse/human skin engraftment model. Results showed correction of epidermal architecture in both OTCs and regenerated skin grafts. Importantly, the results from corrected skin grafts indicated that even where detectable LEKTI expression was restored to a limited numbers of cells, a wider bystander benefit occurred around these small populations. As LEKTI is a secreted protein, the genetically modified graft may provide not only an immediate local protective barrier, but also act as a source of secreted LEKTI providing a generalized benefit following ex-vivo gene therapy. Netherton syndrome (NS, OMIM 256500) is a rare autosomal recessive disorder manifesting with congenital ichthyosis, a specific hair shaft abnormality named trichorrhexis invaginata, and atopic manifestations. Because of severe complications frequently occurring in the neonatal period, NS prognosis can be poor in infancy. NS is due to loss-of-function mutations in the SPINK5 gene and to the consequent lack of expression of its encoded protein LEKTI in the skin and all stratified epithelial tissues. Following the identification of the NS causative gene and protein, specific diagnostic tools have been developed, thus breaking up the challenge of distinguishing NS from other congenital ichthyoses with overlapping features, and from severe, early-onset forms of atopic dermatitis or psoriasis. Intensive efforts to extend the knowledge into the pathomechanisms of NS have also been made. However, NS management is still problematic due to the lack of specific treatment and unmet needs. This overview summarizes the current state of the art in NS research with an emphasis on the progress made toward disease-specific innovative therapy development. We describe here eleven different mutations in SPINK5, encoding the serine protease inhibitor LEKTI, in 13 families with Netherton syndrome (NS, MIM256500). Most of these mutations predict premature termination codons. These results disclose a critical role of SPINK5 in epidermal barrier function and immunity, and suggest a new pathway for high serum IgE levels and atopic manifestations. BACKGROUND: Several skin diseases and atopic disorders including Netherton syndrome and atopic dermatitis have been associated with mutations and deviations of expression of SPINK5, the gene encoding the human 15-domain serine proteinase inhibitor LEKTI. The biochemical mechanisms underlying this phenomenon have not yet been fully clarified. OBJECTIVES: To identify target proteinases of LEKTI important for processes of desquamation and inflammation of the skin which will enable the development of specific drugs. METHODS: The inhibitory activities of LEKTI domains 6 and 15 were tested on a number of commercially available serine proteinases and also on the purified kallikreins hK5 and hK7. In addition, recombinant hK5 was used. RESULTS: LEKTI domain 6 is a potent inhibitor of hK5 and hK7, whereas LEKTI domain 15 exhibits inhibitory activity on plasmin. hK5 and hK7 in particular are relevant to skin disorders. CONCLUSIONS: The inhibition of hK5 and hK7 by LEKTI domain 6 indicates an important regulatory role of LEKTI in processes of skin desquamation and inflammation, which may explain the severe pathological symptoms associated with abnormalities of SPINK5 and/or its expression. Thus, LEKTI represents a potential drug for the treatment of these disorders. BACKGROUND: Loss-of-function mutations in the Kazal-type serine protease inhibitor, LEKTI, encoded by the SPINK5 gene cause the rare autosomal recessive skin disease Netherton syndrome (NS). G1258A polymorphism in SPINK5 may be associated with atopic dermatitis, which shares several clinical features with NS. OBJECTIVES: To determine if the phenotype of NS can be caused by a single null mutation in SPINK5 combined with the homozygous G1258A polymorphism. METHODS: We screened mutations in the gene SPINK5 by direct DNA sequencing and position cloning and examined the expressions of the SPINK5-encoded protein LEKTI and other relevant proteins by immunostaining and immunoblot. RESULTS: We describe here a patient who was clinically diagnosed with NS and carried a single null mutation in SPINK5 combined with the homozygous G1258A polymorphism. SPINK5 mRNA was present at normal levels and LEKTI was expressed in the epidermis. Nonetheless, the putative downstream LEKTI substrates stratum corneum trypsin-like enzyme (SCTE), desmoglein 1 and protein markers of keratinocyte differentiation were expressed abnormally, similar to that seen in NS if two null mutant alleles are present. CONCLUSION: This finding indicates that haploinsufficiency of SPINK5 can cause the NS phenotype in the presence of one null mutation with homozygous G1258A polymorphisms in SPINK5, and this could impair the function of LEKTI and therefore acts as a true mutation. Netherton syndrome (NS) is a rare autosomal recessive disorder characterized by ichthyosiform scaling, hair abnormalities, and variable atopic features. Mutations in the serine protease inhibitor Kazal type 5 (SPINK5) gene leading to lymphoepithelial Kazal-type-related inhibitor (LEKTI) deficiency cause NS. Growth retardation is a classic feature of NS, but growth hormone (GH) deficiency with subsequent response to GH therapy is not documented in the literature. It is proposed that a lack of inhibition of proteases due to a deficiency of LEKTI in the pituitary gland leads to the overprocessing of human GH in NS. Herein we report three patients with NS who had growth retardation associated with GH deficiency and responded well to GH therapy. Netherton syndrome is a rare autosomal recessive disorder characterized by the triad of ichthyosiform erythrodermia, typical hair dysplasia, and severe atopic features. The broad range of variable expression of this disease is well described and 20% of complications occur during the neonatal period such as hypernatremic dehydration, electrolyte imbalances, recurrent or severe infections, and failure to thrive. Mutation of the SPINK5 gene has been identified as disease-causing in Netherton syndrome, but the pathophysiology still remains unclear. Almost all SPINK5 mutations result in the absence of the serine-protease inhibitor LEKTI protein in both keratinocytes and lymphocytes. In this study, we report on a severe form of Netherton syndrome observed in three patients within a large inbred Rom family. All of them died in the first months of life despite early treatment. They were found to be homozygous for the c.1431-12G>A SPINK5 gene mutation, which has not been associated with a lethal form of the disease thus far. This family illustrates the extreme phenotype of Netherton disease of neonatal onset. Molecular diagnosis allowed further genetic counseling and prenatal testing during other pregnancies. Netherton syndrome is a severe autosomal recessive skin disorder characterized by congenital erythroderma, a specific hair-shaft abnormality, and atopic manifestations with high IgE levels. Recently, we identified SPINK5, which encodes the serine protease inhibitor Kazal-type 5 protein (LEKTI), as the defective gene in Netherton syndrome. Here we describe the intron-exon organization of the gene and characterize the SPINK5 mutations in patients from 21 families of different geographic origin, using denaturing high performance liquid chromatography and direct sequencing. We identified 18 mutations, of which 13 were novel and seven (39%) were recurrent. The majority of the mutations were clustered between exons 1-8 and exons 21-26. They comprised four nonsense mutations (22%), eight frameshift insertions or deletions (44%), and six splice-site defects (33%). All mutations predict the formation of premature termination codons. Northern blot analysis showed variable reduction of SPINK5 mutant transcript levels, suggesting variable efficiency of nonsense-mediated mRNA decay. Seven patients were homozygotes, eight were compound heterozygotes, and five were heterozygotes with only one identifiable SPINK5 mutation. Five mutations, one of which resulted in perinatal lethal disease in three families, were associated with certain ethnic groups. We also describe 45 intragenic polymorphisms in the patients studied. The clinical features of erythroderma, trichorrhexis invaginata, and atopic manifestations were present in the majority of affected individuals and ichthyosis linearis circumflexa was seen in 12 out of 24 patients. Interfamilial and intrafamilial variation in disease severity was observed, with no clear correlation between mutations and phenotype, suggesting that the degree of severity may be affected by other factors. Netherton's syndrome is a rare autosomal recessive disorder caused by mutations of the SPINK5 gene, which encodes the lymphoepithelial Kazal-type-related inhibitor (LEKTI) protein. We observed microstructural changes and detected LEKTI activity and SPINK5 gene mutation in three Chinese patients with Netherton's syndrome. Decreased LEKTI activity was found in the skin of patients. Lamellar bodies and foci of electron-dense material were detected in the intercellular spaces of the stratum corneum. A novel homozygous splicing mutation of 1430+2 T-->G was found in the SPINK5 gene in one proband. No mutation was found in the other family. BACKGROUND: Netherton syndrome (NS, MIM 256500) is a potential live threatening autosomal-recessive skin disorder clinically characterized by the trias of congenital erythroderma, hair shaft anomalies and atopic diathesis. It is caused by mutations in the gene SPINK5 resulting in a deficiency of its processed protein named lympho-epithelial Kazal-type related inhibitor (LEKTI). LEKTI controls the activity of several serine proteases in the skin that are involved in terminal differentiation. Loss of LEKTI results in protease hyperactivity, increased degradation of intercellular junctions, reduced stratum corneum adhesion and impaired skin barrier function. Today NS can only be treated symptomatically. OBJECTIVE: Does gene transfer offer a therapeutic option for NS in the future? METHODS: A recombinant adeno-associated virus type 2 vector was constructed containing the full length cDNA (rAAV2/C-SPINK5) of functional human LEKTI. Infectious virus particles were used for transfection of LEKTI-deficient-keratinocytes of NS patients in vitro. RESULTS: Gene transfer of SPINK5 in NS-keratinocytes led to a five-fold increase in mRNA expression of SPINK5 reaching almost 75% of normal value. The functionality of the expressed LEKTI was proven in a hydrolytic activity assay demonstrating that the activity of LEKTI after gene transfer increased closely to the level seen in keratinocytes of healthy individuals. CONCLUSION: The results provide first evidence that gene transfer of SPINK5 results in increased LEKTI activity in NS-keratinocytes, thus offering a rational to further pursue such a gene therapy approach for NS. Netherton syndrome is a rare disorder inherited in an autosomal recessive pattern consisting of ichthyosiform dermatosis, hair shaft abnormalities (trichorrhexis invaginata), and an atopic diathesis. Patients with Netherton syndrome have been found to have a mutation on chromosome 5q32 in a gene named SPINK5 (serine protease inhibitor, Kazal type-5), which encodes an inhibitor of serine proteases called LEKTI. We report a female patient with previously undiagnosed Netherton syndrome who presented to participate in a clinical research trial investigating the benefit of topical tacrolimus 0.03% ointment [Protopic (Fujisawa Pharmaceutical Co. Ltd., Japan)] for the treatment of atopic dermatitis. This patient was confirmed to have a gene mutation in SPINK5. Current literature suggests a relative contraindication for use of topical tacrolimus in patients with Netherton syndrome owing to concern for increased systemic absorption of the drug. Our patient was not able to tolerate topical tacrolimus owing to local irritation, and did not derive any benefit from therapy. Though rare, when evaluating patients with a possible diagnosis of atopic dermatitis, an index of suspicion for Netherton Syndrome must be maintained. History and overall clinical findings, especially in regards to examination of the hair, will aid in diagnosis. Netherton syndrome (NS) is a congenital ichthyosiform dermatosis caused by serine protease inhibitor Kazal-type 5 (SPINK5) mutations. Tissue kallikreins (KLKs) and lymphoepithelial Kazal-type-related inhibitor (LEKTI) (SPINK5 product) may contribute to the balance of serine proteases/inhibitors in skin and influence skin barrier function and desquamation. SPINK5 mutations, causing NS, lead to truncated LEKTI; each NS patient possesses LEKTI of a different length, depending on the location of mutations. This study aims to elucidate genotype/phenotype correlations in Japanese NS patients and to characterize the functions of each LEKTI domain. Since we were unable to demonstrate truncated proteins in tissue from patients with NS, we used recombinant protein to test the hypothesis that the length of LEKTI correlated with protease inhibitory activity. Genotype/phenotype correlations were observed with cutaneous severity, growth retardation, skin infection, stratum corneum (SC) protease activities, and KLK levels in the SC. Predominant inhibition by LEKTI domains against overall SC protease activities was trypsin-like (Phe-Ser-Arg-) activity by LEKTI domains 6-12, plasmin- and trypsin-like (Pro-Phe-Arg-) activities by domains 12-15, chymotrypsin-like activity by all domains, and furin-like activity by none. KLK levels were significantly elevated in the SC and serum of NS patients. These data link LEKTI domain deficiency and clinical manifestations in NS patients and pinpoints to possibilities for targeted therapeutic interventions. |
389 | Which disease of the central nervous system is characterized by the presence of Lewy bodies? | Parkinson s disease (PD) is one of the most common degenerative disorders of the central nervous system that produces motor and non-motor symptoms. The majority of cases are idiopathic and characterized by the presence of Lewy bodies containing fibrillar α-synuclein | [23979994, 25514659, 20174468, 23587141, 2085926, 22251432, 19155272, 23531432, 24095115, 1534893, 24291999, 10986355, 24465140, 23225525, 19877240, 23281786, 22355263] | 496 | Parkinson's disease (PD) is the second most common neurodegenerative disorder that is characterized by two major neuropathological hallmarks: the degeneration of dopaminergic neurons in the substantia nigra (SN) and the presence of Lewy bodies in the surviving SN neurons, as well as other regions of the central and peripheral nervous system. Animal models have been invaluable tools for investigating the underlying mechanisms of the pathogenesis of PD and testing new potential symptomatic, neuroprotective and neurorestorative therapies. However, the usefulness of these models is dependent on how precisely they replicate the features of clinical PD with some studies now employing combined gene-environment models to replicate more of the affected pathways. The rotenone model of PD has become of great interest following the seminal paper by the Greenamyre group in 2000 (Betarbet et al., 2000). This paper reported for the first time that systemic rotenone was able to reproduce the two pathological hallmarks of PD as well as certain parkinsonian motor deficits. Since 2000, many research groups have actively used the rotenone model worldwide. This paper will review rotenone models, focusing upon their ability to reproduce the two pathological hallmarks of PD, motor deficits, extranigral pathology and non-motor symptoms. We will also summarize the recent advances in neuroprotective therapies, focusing on those that investigated non-motor symptoms and review rotenone models used in combination with PD genetic models to investigate gene-environment interactions. A number of neurodegenerative diseases including Parkinson's disease, dementia with Lewy bodies (DLB) and multiple system atrophy are characterized by the formation and intraneuronal accumulation of fibrillar aggregates of alpha-synuclein (alpha-syn) protein in affected brain regions. These and other findings suggest that the accumulation of alpha-syn in the brain plays an important role in the pathogenesis of these diseases. However, more recently it has been reported that early amyloid aggregates or 'soluble oligomers' are the pathogenic species that lead to neurodegeneration and neuronal cell death rather than the later 'mature fibrils'. In this study, we investigated the presence of alpha-syn oligomers in brain lysates prepared from frozen post-mortem brains of normal, Alzheimer's disease and DLB patients. The brain extracts were subjected to high speed centrifugation, to remove insoluble alpha-syn aggregates, followed by specific detection of soluble oligomers in the supernatants by employing FILA-1, an antibody that specifically binds to alpha-syn aggregates, but not to alpha-syn monomers, or to tau or beta-amyloid aggregates. Using this novel enzyme-linked immunosorbent assay (ELISA) method to quantify the amounts of alpha-syn oligomers in the brain extracts, our data clearly show an increase in the levels of soluble oligomers of alpha-syn in the DLB brains compared to those with Alzheimer's disease and the controls (P < 0.0001). Our findings provide strong evidence to support the contention that elevated soluble oligomers of alpha-syn are involved in the pathogenesis of DLB. Furthermore, these findings establish FILA-1 as a very sensitive tool for the detection of oligomeric forms of alpha-syn in human brain lysates. Parkinson's disease is characterized by neuronal death in the substantia nigra and the presence of intracellular inclusions of α-synuclein in the Lewy bodies. Several lines of data support a role for iron in Parkinson's disease: iron is present in Lewy bodies, iron accumulates in the dopaminergic neurons in the substantia nigra, and Parkinson's disease is correlated with polymorphisms of several genes implicated in iron metabolism. Furthermore, iron can compromise the solubility of α-synuclein through direct interaction and can induce neurotoxicity in vitro. Here, we investigate the possible neuroprotective effect of the iron chelator deferoxamine in vivo to elucidate whether iron chelation can provide meaningful therapy for Parkinson's disease. Hence, we used a Parkinson's disease animal model based on unilateral injection of a recombinant adeno-associated viral vector encoding α-synuclein in the rat midbrain. Rats were treated with a novel deferoxamine delivery approach: 6 mg of the compound was administered intranasally three times a week for 3 or 7 weeks. The behavior of the animals and histopathological changes in the brain were analyzed. Our data show that although intranasal administration of deferoxamine in rats did not protect them from dopaminergic cell death, it did decrease the number of the pathological α-synuclein formations at the terminal level. In addition, this treatment resulted in changes in the immune response and an overall partial improvement in motor behavior. Taken together, our data show that in vivo iron chelation can modulate α-synuclein-induced pathology in the central nervous system. Our data suggest that chronic administration of intranasal deferoxamine may be a valid approach to limiting the mishandling of α-synuclein in the central nervous system observed in Parkinson's disease and slowing disease progression. It is well known that autonomic failure is severer in patients with dementia with Lewy bodies (DLB) compared with patients with Parkinson's disease (PD). According to the Braak's hypothesis, Lewy bodies first appear in the olfactory bulb or peripheral autonomic nervous system. Lewy bodies in the peripheral autonomic nervous system ascend to dorsal motor nuclei of vagus nerve, while those in the olfactory bulb expand to the limbic system. Lewy bodies later attain the substantia nigra. However, it seems that Braak staging can not explain difference in severity of autonomic failure between DLB and PD. As a possibility, in DLB patients with significant autonomic failure, Lewy bodies may have been localized to the peripheral autonomic nervous system in a long time before onset of dementia or parkinsonism, and propagation of Lewy bodies into the central nervous system may be initiated by apparition of certain promotion factor, such as ageing and amyloid-β. Parkinson's disease (PD) and related Lewy body diseases are characterized by deposition of α-synuclein aggregates in both the central nervous system and peripheral nervous system. Synucleinopathy lesions spread to larger brain areas as the disease progresses, and prion-like cell-to-cell transmission of aggregated α-synuclein is thought to be the underlying mechanism for this pathological spreading. LRRK2 is another protein linked to the pathogenesis of PD, and its presence in Lewy bodies has attracted much attention as to whether LRRK2 and α-synuclein interplay during the pathogenesis of PD. However, the relationship between these two crucial proteins still remains unclear. In this review article, we will discuss the current state of knowledge in terms of how these proteins cause the disease and provide the hypothetical mechanisms by which LRRK2 might modify the generation and progression of synucleinopathy. Protein aggregation within the central nervous system has been recognized as a defining feature of neurodegenerative diseases since the early 20th century. Since that time, there has been a growing list of neurodegenerative disorders, including Parkinson disease, which are characterized by inclusions of specific pathogenic proteins. This has led to the long-held dogma that these characteristic protein inclusions, which are composed of large insoluble fibrillar protein aggregates and visible by light microscopy, are responsible for cell death in these diseases. However, the correlation between protein inclusion formation and cytotoxicity is inconsistent, suggesting that another form of the pathogenic proteins may be contributing to neurodegeneration. There is emerging evidence implicating soluble oligomers, smaller protein aggregates not detectable by conventional microscopy, as potential culprits in the pathogenesis of neurodegenerative diseases. The protein α-synuclein is well recognized to contribute to the pathogenesis of Parkinson disease and is the major component of Lewy bodies and Lewy neurites. However, α-synuclein also forms oligomeric species, with certain conformations being toxic to cells. The mechanisms by which these α-synuclein oligomers cause cell death are being actively investigated, as they may provide new strategies for diagnosis and treatment of Parkinson disease and related disorders. Here we review the possible role of α-synuclein oligomers in cell death in Parkinson disease and discuss the potential clinical implications. Although Parkinson's disease with later dementia (PDD) and dementia with Lewy bodies (DLB) are pathologically characterized by the presence of intraneuronal Lewy inclusion bodies, amyloid deposition is also associated to varying degrees with both these disorders. Fibrillar amyloid load can now be quantitated in vivo with positron emission tomography (PET) using imaging biomarkers. Here the reported findings of 11C-PIB PET studies concerning the amyloid load associated with PD and its influence on dementia are reviewed. It is concluded that the presence of amyloid acts to accelerate the dementia process in Lewy body disorders, though has little influence on its nature. Anti-amyloid strategies could be a relevant approach for slowing dementia in a number of DLB and PDD cases. Parkinson's disease, also known as paralysis agitans, is a progressive degenerative disorder of the central nervous system, with onset usually between the ages of 50 and 65 years, and is associated with loss of dopaminergic neurons in the subsantia nigra and the presence of Lewy bodies. It is characterized by the triad of resting tremor, muscular rigidity and bradykinesia. Often-accompanying abnormalities include disorders of equilibrium, posture and autonomic function, including micturition. Symptoms from the lower urinary tract add a significant comorbidity factor in these patients. The incidence and prevalence of lower urinary tract dysfunction rise with increasing progression of the underlying neurological disease. They present a troublesome and difficult to treat health issue with a profound impact on the patient's quality of life. Storage symptoms seem to predominate. In the long term, renal function might be compromised, mainly as a result of elevated intravesical pressure. Various conservative, minimally-invasive and surgical treatment options are available to prevent harmful sequelae, and to improve the quality of life of these patients. We present an overview of current and prospective treatment strategies. Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are characterized by abnormal deposition of α-synuclein aggregates in many regions of the central and peripheral nervous systems. Accumulating evidence suggests that the α-synuclein pathology initiates in a few discrete regions and spreads to larger areas in the nervous system. Recent pathological studies of PD patients have raised the possibility that the enteric nervous system is one of the initial sites of α-synuclein aggregation and propagation. Here, we evaluated the induction and propagation of α-synuclein aggregates in the enteric nervous system of the A53T α-synuclein transgenic mice after injection of human brain tissue extracts into the gastric walls of the mice. Western analysis of the brain extracts showed that the DLB extract contained detergent-stable α-synuclein aggregates, but the normal brain extract did not. Injection of the DLB extract resulted in an increased deposition of α-synuclein in the myenteric neurons, in which α-synuclein formed punctate aggregates over time up to 4 months. In these mice, inflammatory responses were increased transiently at early time points. None of these changes were observed in the A53T mice injected with saline or the normal brain extract, nor were these found in the wild type mice injected with the DLB extract. These results demonstrate that pathological α-synuclein aggregates present in the brain of DLB patient can induce the aggregation of endogenous α-synuclein in the myenteric neurons in A53T mice, suggesting the transmission of synucleinopathy lesions in the enteric nervous system. |
390 | Which deiodinase is known to be present in liver? | High D1 and D3 activities are present in fetal human liver, and high D1 and mostly absent D3 activities are present in adult human liver. | [8550759, 9709961, 9794474, 7629231, 9389494, 15072569] | 497 | The uptake and metabolism of T3 and rT3 was studied in human liver-derived HepG2 cells. The results showed a saturable, time-dependent, and ouabain-sensitive increase in nuclear bound T3. The effects of ouabain (0.5 mmol/L) and unlabeled T3 (10 nmol/L and 10 mumol/L) were much more pronounced at the nuclear level, suggesting the presence of a nonspecific component in total cellular binding. Nuclear binding of rT3 remained below the detection limit in all experiments. Comparison of rT3 metabolism in HepG2 cells and primary cultures of rat hepatocytes showed an approximately 10-fold lower iodide production in HepG2 cells. Iodide production was decreased in the presence of ouabain and almost absent in the presence of propylthiouracil (100 mumol/L). Our data confirmed the presence of a carrier-mediated uptake system for both T3 and rT3. Metabolism data indicated functional type I deiodinase activity in HepG2 cells, the presence of glucuronidating enzymes, and the absence of thyroid hormone sulfotransferase activity. Based on these data, we propose that HepG2 cells provide an appropriate model for thyroid hormone handling by human liver. In addition, we suggest that in human liver sulfation of thyroid hormone, and therefore deiodination of T3 is of only minor importance. The role of the deiodinases D1, D2, and D3 in the tissue-specific and time-dependent regulation of thyroid hormone bioactivity during fetal development has been investigated in animals but little is known about the ontogeny of these enzymes in humans. We analyzed D1, D2, and D3 activities in liver microsomes from 10 fetuses of 15-20 weeks gestation and from 8 apparently healthy adult tissue transplant donors, and in liver homogenates from 2 fetuses (20 weeks gestation), 5 preterm infants (27-32 weeks gestation), and 13 term infants who survived up to 39 weeks postnatally. D1 activity was determined using 1 microM [3',5'-125I]rT3 as substrate and 10 mM dithiothreitol (DTT) as cofactor, D2 activity using 1 nM [3',5'-125I]T4 and 25 mM DTT in the presence of 1 mM 6-propyl-2-thiouracil (to block D1 activity) and 1 microM T3 (to block D3 activity), and D3 activity using 10 nM [3,5-125I]T3 and 50 mM DTT, by quantitation of the release of 125I. The assays were validated by high performance liquid chromatography of the products, and kinetic analysis [Michaelis-Menten constant (Km) of rT3 for D1: 0.5 microM; Km of T3 for D3: 2 nM]. In liver homogenates, D1 activity was not correlated with age, whereas D3 activity showed a strong negative correlation with age (r -0.84), with high D3 activities in preterm infants and (except in 1 infant of 35 weeks) absent D3 activity in full-term infants. In microsomes, D1 activities amounted to 4.3-60 pmol/min/mg protein in fetal livers and to 170-313 pmol/min/mg protein in adult livers, whereas microsomal D3 activities were 0.15-1.45 pmol/min/mg protein in fetuses and <0.1 pmol/min/mg protein in all but one adult. In the latter sample, D3 activity amounted to 0.36 pmol/min/mg protein. D2 activity was negligible in both fetal and adult livers. These findings indicate high D1 and D3 activities in fetal human liver, and high D1 and mostly absent D3 activities in adult human liver. Therefore, the low serum T3 levels in the human fetus appear to be caused by high hepatic (and placental) D3 activity rather than caused by low hepatic D1 activity. The occasional expression of D3 in adult human liver is intriguing and deserves further investigation. In systemic nonthyroidal illness (NTI), peripheral production of T3 from T4 is decreased, resulting in a decreased serum T3 concentration. We investigated whether factors in serum of NTI patients may play a role in this energy-saving adaptation mechanism. Metabolism of T4 and T3 by rat hepatocytes in primary culture was measured in the presence of 10% serum of normal subjects or of patients with NTI and related to the severity of disease. Patients with NTI were grouped according to serum thyroid hormone abnormalities: group I, serum rT3, T3, and T4 normal; group III, rT3 elevated, T3 decreased, T4 normal; group IV, rT3 elevated, T3 and T4 decreased. Compared with metabolism in the presence of normal serum, metabolism of T4 and to a lesser extent of T3 was progressively decreased in the presence of serum of patients of groups I-IV. A decreased net deiodination of T4 and T3 (corrected for differences in free hormone concentration) without an increase in conjugated T4 and T3 (corrected for differences in free hormone concentration) was observed, similar to results in experiments with compounds inhibiting transport into the cells and not the metabolic processes (5' deiodination) per se. Deiodination of T4 in vitro was correlated with serum T3 concentration of the patient (r = 0.69). Serum of patients with NTI influences thyroid hormone handling by hepatocytes comparable to the effect of transport inhibitors and not to that of the 5'-deiodinase inhibitor propylthiouracil, suggesting that decreased thyroid hormone transport over the cell membrane may play a role in lowered T3 production in NTI. In embryonic chicken liver (ECL) two types of iodothyronine deiodinases are expressed: D1 and D3. D1 catalyzes the activation as well as the inactivation of thyroid hormone by outer and inner ring deiodination, respectively. D3 only catalyzes inner ring deiodination. D1 and D3 have been cloned from mammals and amphibians and shown to contain a selenocysteine (Sec) residue. We characterized chicken D1 and D3 complementary DNAs (cDNAs) and studied the expression of hepatic D1 and D3 messenger RNAs (mRNAs) during embryonic development. Oligonucleotides based on two amino acid sequences strongly conserved in the different deiodinases (NFGSCTSecP and YIEEAH) were used for reverse transcription-PCR of poly(A+) RNA isolated from embryonic day 17 (E17) chicken liver, resulting in the amplification of two 117-bp DNA fragments. Screening of an E17 chicken liver cDNA library with these probes led to the isolation of two cDNA clones, ECL1711 and ECL1715. The ECL1711 clone was 1360 bp long and lacked a translation start site. Sequence alignment showed that it shared highest sequence identity with D1s from other vertebrates and that the coding sequence probably lacked the first five nucleotides. An ATG start codon was engineered by site-directed mutagenesis, generating a mutant (ECL1711M) with four additional codons (coding for MGTR). The open reading frame of ECL1711M coded for a 249-amino acid protein showing 58-62% identity with mammalian D1s. An in-frame TGA codon was located at position 127, which is translated as Sec in the presence ofa Sec insertion sequence (SECIS) identified in the 3'-untranslated region. Enzyme activity expressed in COS-1 cells by transfection with ECL1711M showed the same catalytic, substrate, and inhibitor specificities as native chicken D1. The ECL1715 clone was 1366 bp long and also lacked a translation start site. Sequence alignment showed that it was most homologous with D3 from other species and that the coding sequence lacked approximately the first 46 nucleotides. The deduced amino acid sequence showed 62-72% identity with the D3 sequences from other species, including a putative Sec residue at a corresponding position. The 3'-untranslated region of ECL1715 also contained a SECIS element. These results indicate that ECL1711 and ECL1715 are near-full-length cDNA clones for chicken D1 and D3 selenoproteins, respectively. The ontogeny of D1 and D3 expression in chicken liver was studied between E14 and 1 day after hatching (C1). D1 activity showed a gradual increase from E14 until C1, whereas D1 mRNA level remained relatively constant. D3 activity and mRNA level were highly significantly correlated, showing an increase from E14 to E17 and a strong decrease thereafter. These results suggest that the regulation of chicken hepatic D3 expression during embryonic development occurs predominantly at the pretranslational level. |
391 | Which proteins participate in the formation of the Notch transcriptional activation complex? | The Notch intracellular domain (NICD) forms a transcriptional activation complex with the DNA-binding factor CSL and a transcriptional co-activator of the Mastermind family (MAML). ICN binds to a highly conserved DNA-binding transcription factor called CSL (also known as RBP-Jkappa, CBF1, Suppressor of Hairless, and Lag-1) and recruits Mastermind-like transcriptional co-activators to form a transcriptional activation complex. | [21124806, 20118921, 21245387, 18758478, 11536431, 12205678, 12644465, 22325781, 20972443, 16530044] | 498 | BACKGROUND: Canonical Notch signaling is initiated when ligand binding induces proteolytic release of the intracellular part of Notch (ICN) from the cell membrane. ICN then travels into the nucleus where it drives the assembly of a transcriptional activation complex containing the DNA-binding transcription factor CSL, ICN, and a specialized co-activator of the Mastermind family. A consensus DNA binding site motif for the CSL protein was previously defined using selection-based methods, but whether subsequent association of Notch and Mastermind-like proteins affects the DNA binding preferences of CSL has not previously been examined. PRINCIPAL FINDINGS: Here, we utilized protein-binding microarrays (PBMs) to compare the binding site preferences of isolated CSL with the preferred binding sites of CSL when bound to the CSL-binding domains of all four different human Notch receptors. Measurements were taken both in the absence and in the presence of Mastermind-like-1 (MAML1). Our data show no detectable difference in the DNA binding site preferences of CSL before and after loading of Notch and MAML1 proteins. CONCLUSIONS/SIGNIFICANCE: These findings support the conclusion that accrual of Notch and MAML1 promote transcriptional activation without dramatically altering the preferred sites of DNA binding, and illustrate the potential of PBMs to analyze the binding site preferences of multiprotein-DNA complexes. The Notch signalling pathway has a crucial function in determining cell fates in multiple tissues within metazoan organisms. On binding to ligands, the Notch receptor is cleaved proteolytically and releases its intracellular domain (NotchICD). The NotchICD enters the nucleus and acts cooperatively with other factors to stimulate the transcription of target genes. High levels of Notch-mediated transcriptional activation require the formation of a ternary complex consisting of NotchICD, CSL (CBF-1, suppressor of hairless, LAG-1) and a Mastermind family member. However, it is still not clear how the formation of the ternary complex is regulated. Here we show that Nemo-like kinase (NLK) negatively regulates Notch-dependent transcriptional activation by decreasing the formation of this ternary complex. Using a biochemical screen, we identified Notch as a new substrate of NLK. NLK-phosphorylated Notch1ICD is impaired in its ability to form a transcriptionally active ternary complex. Furthermore, knockdown of NLK leads to hyperactivation of Notch signalling and consequently decreases neurogenesis in zebrafish. Our results both define a new function for NLK and reveal a previously unidentified mode of regulation in the Notch signalling pathway. Notch transmembrane receptors direct essential cellular processes, such as proliferation and differentiation, through direct cell-to-cell interactions. Inappropriate release of the intracellular domain of Notch (N(ICD)) from the plasma membrane results in the accumulation of deregulated nuclear N(ICD) that has been linked to human cancers, notably T-cell acute lymphoblastic leukemia (T-ALL). Nuclear N(ICD) forms a transcriptional activation complex by interacting with the coactivator protein Mastermind-like 1 and the DNA binding protein CSL (for CBF-1/Suppressor of Hairless/Lag-1) to regulate target gene expression. Although it is well understood that N(ICD) forms a transcriptional activation complex, little is known about how the complex is assembled. In this study, we demonstrate that N(ICD) multimerizes and that these multimers function as precursors for the stepwise assembly of the Notch activation complex. Importantly, we demonstrate that the assembly is mediated by N(ICD) multimers interacting with Skip and Mastermind. These interactions form a preactivation complex that is then resolved by CSL to form the Notch transcriptional activation complex on DNA. The Notch pathway is a short-range signaling mechanism between neighboring cells that results in changes in gene expression. Extracellular interactions between Notch receptors and ligands trigger proteolytic cleavage of the receptor Notch. Following cleavage, the freed intracellular domain of Notch (NotchIC) moves from the cytoplasm to the nucleus, engaging the DNA-binding transcription factor CBF-1, Su(H), Lag-1 (CSL)--the nuclear effector of the pathway. NotchIC, together with the transcriptional coactivator Mastermind, form a ternary complex with CSL that activates transcription from genes that are responsive to Notch signaling. Illuminating the molecular details that underlie formation of the transcriptionally active CSL-NotchIC-Mastermind ternary complex is key for understanding how genes are turned on in response to a Notch signal. Recently, several studies using biophysical and computational methods have scrutinized how the CSL-NotchIC-Mastermind ternary complex forms and the role individual domains play in this process. These detailed analyses have provided a wealth of molecular insights into the assembly of a Notch pathway active transcription complex but have also raised several intriguing, yet confounding questions. This review will focus on the findings of these recent biophysical studies and provide speculative models that address these unanswered questions. Mastermind (Mam) is a component of Notch pathway signaling. In combination with the intracellular domain of Notch and Suppressor of Hairless, Mam forms a transcriptional activation complex. We have initiated a genetic approach to identify other loci involved in Mam function. The screen utilizes engineered mutations in Mam that derive from GAL4-UAS-directed expression of dominant negative constructs. When driven at the wing margin, truncated versions of Mam phenocopy Notch pathway mutations. Correlated with these phenotypes is depression of Notch pathway target expression. Strains expressing truncated versions of Mam were tested for genetic interactions with a large collection of chromosomal deficiencies. Genomic segments that enhanced and suppressed the dominant wing phenotype were identified. These regions may contain uncharacterized loci involved in Notch pathway function. In the developing central nervous system (CNS), Notch signaling preserves progenitor pools and inhibits neurogenesis and oligodendroglial differentiation. It has recently been postulated that Notch instructively drives astrocyte differentiation. Whether the role of Notch signaling in promoting astroglial differentiation is permissive or instructive has been debated. We report here that the astrogliogenic role of Notch is in part mediated by direct binding of the Notch intracellular domain to the CSL DNA binding protein, forming a transcriptional activation complex onto the astrocyte marker gene, glial fibrillary acidic protein (GFAP). In addition, we found that, in CSL-/- neural stem cell cultures, astrocyte differentiation was delayed but continued at a normal rate once initiated, suggesting that CSL is involved in regulating the onset of astrogliogenesis. Importantly, although the classical CSL-dependent Notch signaling pathway is intact and able to activate the Notch canonical target promoter during the neurogenic phase, it is unable to activate the GFAP promoter during neurogenesis. Therefore, the effect of Notch signaling on target genes is influenced by cellular context in regulation of neurogenesis and gliogenesis. Ligand binding by Notch receptors triggers a series of proteolytic cleavages that liberate the intracellular portion of Notch (ICN) from the cell membrane, permitting it to translocate to the nucleus. Nuclear ICN binds to a highly conserved DNA-binding transcription factor called CSL (also known as RBP-Jkappa, CBF1, Suppressor of Hairless, and Lag-1) and recruits Mastermind-like transcriptional co-activators to form a transcriptional activation complex. Using bioinformatics tools, we identified a Rel homology region (RHR) within CSL that was used as a guide to determine the minimal protein requirements for ternary complex formation. The RHR of CSL contains both the N- and C-terminal beta-sheet domains (RHR-n and RHR-c) of typical Rel transcription factors, as judged by circular dichroism spectra. Binding of monomeric CSL to DNA requires the entire RHR of CSL and an additional 125-residue N-terminal sequence, whereas binding to ICN requires only the RHR-n domain. Although the RAM (RBP-Jkappa (recombination-signal-sequence-binding protein for Jkappa genes)-associated molecule) domain of ICN is flexible and relatively unstructured as an isolated polypeptide in solution, it associates stably with CSL on DNA. Recruitment of Mastermind-like 1 (MAML1) to CSL.ICN complexes on DNA requires inclusion of the ankyrin repeat domain of ICN, and N- and C-terminal sequences of CSL extending beyond the DNA-binding region. The requirement for cooperative assembly of the MAML1.ICN.CSL.DNA complex suggests that a primary function of ICN is to render CSL competent for MAML loading. On the basis of our results, we present a working structural model for the organization of the MAML1.ICN.CSL.DNA complex. The Notch intracellular domain (NICD) forms a transcriptional activation complex with the DNA-binding factor CSL and a transcriptional co-activator of the Mastermind family (MAML). The "RAM" region of NICD recruits Notch to CSL, facilitating the binding of MAML at the interface between the ankyrin (ANK) repeat domain of NICD and CSL. Here, we report the X-ray structure of a human MAML1/RAM/ANK/CSL/DNA complex, and probe changes in component dynamics upon stepwise assembly of a MAML1/NICD/CSL complex using HX-MS. Association of CSL with NICD exerts remarkably little effect on the exchange kinetics of the ANK domain, whereas MAML1 binding greatly retards the exchange kinetics of ANK repeats 2-3. These exchange patterns identify critical features contributing to the cooperative assembly of Notch transcription complexes (NTCs), highlight the importance of MAML recruitment in rigidifying the ANK domain and stabilizing its interface with CSL, and rationalize the requirement for MAML1 in driving cooperative dimerization of NTCs on paired-site DNA. Ligand-induced proteolysis of Notch produces an intracellular effector domain that transduces essential signals by regulating the transcription of target genes. This function relies on the formation of transcriptional activation complexes that include intracellular Notch, a Mastermind co-activator and the transcription factor CSL bound to cognate DNA. These complexes form higher-order assemblies on paired, head-to-head CSL recognition sites. Here we report the X-ray structure of a dimeric human Notch1 transcription complex loaded on the paired site from the human HES1 promoter. The small interface between the Notch ankyrin domains could accommodate DNA bending and untwisting to allow a range of spacer lengths between the two sites. Cooperative dimerization occurred on the human and mouse Hes5 promoters at a sequence that diverged from the CSL-binding consensus at one of the sites. These studies reveal how promoter organizational features control cooperativity and, thus, the responsiveness of different promoters to Notch signaling. Notch receptors transduce essential developmental signals between neighboring cells by forming a complex that leads to transcription of target genes upon activation. We report here the crystal structure of a Notch transcriptional activation complex containing the ankyrin domain of human Notch1 (ANK), the transcription factor CSL on cognate DNA, and a polypeptide from the coactivator Mastermind-like-1 (MAML-1). Together, CSL and ANK create a groove to bind the MAML-1 polypeptide as a kinked, 70 A helix. The composite binding surface likely restricts the recruitment of MAML proteins to promoters on which Notch:CSL complexes have been preassembled, ensuring tight transcriptional control of Notch target genes. |
392 | How is the sequence variability defined in antibodies? | The variability at each position of the polypeptide chain is defined as:
Variability = number of different amino acids at a given position / frequency of the most common amino acid at given position. | [15613860, 22067045, 8944774, 16609350, 17353288, 22661385, 22863657, 17258731, 12547627, 20421997, 18721481, 11790764, 12072528, 9783696, 11292724, 7511773, 16517887] | 499 | The utility of immunohistochemistry (IHC) as a screening method for the identification of persons with mutations in the DNA mismatch repair (MMR) genes in hereditary nonpolyposis colorectal cancer (HNPCC) remains to be defined. In this study, we analyzed the value of IHC versus that of microsatellite instability (MSI) testing in predicting mutation status of the MLH1, MSH2, and MSH6 genes in colorectal carcinomas and adenomas, and explored the frequency and significance of immunohistochemical staining variability. The study samples included 83 carcinomas and 29 adenomas derived from 110 patients who had strong family histories of colorectal cancer. Our results showed that IHC correctly predicted MSI status in 76% of the cases with a specificity of 100%. The overall sensitivity of IHC in predicting a germline mutation was 79% (30 of 38) with a specificity of 89% (48 of 54), whereas that of MSI testing was 97% (30 of 31) with a specificity of 83% (35 of 42). Six of 31 analyzable cases that had a disease-causing mutation and exhibited MSI showed normal IHC. The lower sensitivity of IHC was caused mainly by its low sensitivity in detecting MLH1 gene mutation (4 of 9). Coexisting adenomas and carcinomas observed in the same slide (n=12) showed a similar or identical staining pattern for all three proteins. No significant difference was detected in the sensitivity of IHC or MSI in detecting a germline mutation between isolated adenomas and carcinomas. In IHC-positive cases, heterogeneous staining was noted in 30% to 40% of the cases with the three different antibodies, and cytoplasmic staining in 5% to 13%. Weak IHC (defined as positive staining in <10% of the tumor with weak intensity) was noted in 14 tumors: 5 for the MLH1 antibody, 1 for MSH2, and 8 for MSH6. One of the 5 MLH1 cases exhibited MSI and had an MLH1 germline mutation. Five of the 8 MSH6 cases exhibited MSI and had MSH2 germline mutations. In conclusion, our study shows that 1) IHC identifies a significant portion of colorectal tumors derived from MMR gene germline mutation carriers and can be used as an adjunct measure in the identification of HNPCC families, but IHC cannot replace MSI testing; 2) adenomas have similar MMR protein expression patterns as carcinomas and may serve as an adequate sample for screening purposes in the identification of patients with MMR mutations; 3) not all IHC-positive cases show uniform positivity throughout the tumor; and 4) weak and focal staining of an MMR protein may be associated with MSI or gene mutation or both, suggesting the need to incorporate staining intensity in further IHC studies. IgA is the most abundantly produced antibody and plays an important role in the mucosal immune system. Human IgA is represented by two isotypes, IgA1 and IgA2. The major structural difference between these two subclasses is the presence of nine potential sites of O-glycosylation in the hinge region between the first and second constant region domains of the heavy chain. Thr(225), Thr(228), Ser(230), Ser(232) and Thr(236) have been identified as the predominant sites of O-glycan attachment. The range and distribution of O-glycan chains at each site within the context of adjacent sites in this clustered region create a complex heterogeneity of surface epitopes that is incompletely defined. We previously described the analysis of IgA1 O-glycan heterogeneity by use of high resolution LC-MS and electron capture dissociation tandem MS to unambiguously localize all amino acid attachment sites in IgA1 (Ale) myeloma protein. Here, we report the identification and elucidation of IgA1 O-glycopeptide structural isomers that occur based on amino acid position of the attached glycans (positional isomers) and the structure of the O-glycan chains at individual sites (glycan isomers). These isomers are present in a model IgA1 (Mce1) myeloma protein and occur naturally in normal human serum IgA1. Variable O-glycan chains attached to Ser(230), Thr(233) or Thr(236) produce the predominant positional isomers, including O-glycans composed of a single GalNAc residue. These findings represent the first definitive identification of structural isomeric IgA1 O-glycoforms, define the single-site heterogeneity for all O-glycan sites in a single sample, and have implications for defining epitopes based on clustered O-glycan variability. A glutathione-dependent formaldehyde dehydrogenase (class III alcohol dehydrogenase) has been characterized from Arabidopsis thaliana. This plant enzyme exhibits kinetic and molecular properties in common with the class III forms from mammals, with a K(m) for S-hydroxymethylglutathione of 1.4 microM, an anodic electrophoretic mobility (pI: 5.3-5.6) and a cross-reaction with anti-(rat class III alcohol dehydrogenase) antibodies. The enzyme structure, deduced from the cDNA sequence, fits into the complex system of alcohol dehydrogenases and shows that all life forms share the class III protein type. The corresponding mRNA is 1.4 kb and present in all plant organs; a single copy of the gene is found in the genome. The class III structural variability is different from that of the ethanol-active enzyme types in both vertebrates (class I) and plants (class P), although class P conserves more of the class III properties than class I does. Also the enzymatic properties differ between the two ethanol-active classes. Active-site variability and exchanges at essential residues (Leu/Gly57, Asp/Arg115) may explain the distinct kinetics. These patterns are consistent with two different metabolic roles for the ethanol-active enzymes, a more constant function, reduction of acetaldehyde during hypoxia, for class P, and a more variable function, the detoxication of alcohols and participation in metabolic conversions, for class I. A sequence motif, Pro-Xaa-Ile/Val-Xaa-Gly-His-Glu-Xaa-Xaa-Gly, common to all medium-chain alcohol dehydrogenases is defined. Respiratory pathogens, such as Neisseria meningitidis, secrete site-specific proteases able to cleave human immunoglobulin A1 (IgA1), the first line of defense at mucosal membranes. Bacterial isolates show wide variability in IgA1 protease activity, and those isolated from patients with clinical infection possess the highest levels of activity. A feature of this enzyme is the self-cleavage required for secretion of the mature extracellular form. Known cleavage targets contain a proline-rich consensus recognition sequence, Pro-Pro-Ser-Pro, residing in the variable linker region that connects the protease and translocator domains. Here, we report the sequence of the NMB IgA1 protease and the unexpected self-cleavage and subsequent extracellular release of mature IgA1 protease from mutants lacking the previously defined consensus cleavage site. We investigated the possible link between enzyme secretion and variability in the linker sequence segment using site-directed mutagenesis and linker domain swapping to construct mutated and chimeric forms of the IgA1 protease from N. meningitidis strain NMB. The observed change in secreted activity levels compared to the wild-type clone indicated that the precise amino acid sequence of the intervening region, between mature IgA1 protease and the beta-core translocator domain, influences the efficacy of autoproteolytic processing. The broader specificity uncovered for the NMB IgA1 protease suggests that it could cleave a far wider range of human proteins than previously appreciated. Designing proteins that reflect the natural variability of a pathogen is essential for developing novel vaccines and drugs. Flaviviruses, including Dengue (DENV) and West Nile (WNV), evolve rapidly and can "escape" neutralizing monoclonal antibodies by mutation. Designing antigens that represent many distinct strains is important for DENV, where infection with a strain from one of the four serotypes may lead to severe hemorrhagic disease on subsequent infection with a strain from another serotype. Here, a DENV physicochemical property (PCP)-consensus sequence was derived from 671 unique sequences from the Flavitrack database. PCP-consensus proteins for domain 3 of the envelope protein (EdomIII) were expressed from synthetic genes in Escherichia coli. The ability of the purified consensus proteins to bind polyclonal antibodies generated in response to infection with strains from each of the four DENV serotypes was determined. The initial consensus protein bound antibodies from DENV-1-3 in ELISA and Western blot assays. This sequence was altered in 3 steps to incorporate regions of maximum variability, identified as significant changes in the PCPs, characteristic of DENV-4 strains. The final protein was recognized by antibodies against all four serotypes. Two amino acids essential for efficient binding to all DENV antibodies are part of a discontinuous epitope previously defined for a neutralizing monoclonal antibody. The PCP-consensus method can significantly reduce the number of experiments required to define a multivalent antigen, which is particularly important when dealing with pathogens that must be tested at higher biosafety levels. BACKGROUND & AIMS: Broadly reactive neutralizing antibodies (nAbs) and multispecific T-cell responses are generated during chronic hepatitis C virus (HCV) infection and yet fail to clear the virus. This study investigated the development of autologous nAb and HCV-glycoprotein-specific T-cell responses and their effects on viral sequence evolution during chronic infection in order to understand the reasons for their lack of effectiveness. METHODS: Numerous E1E2 sequences were amplified and sequenced from serum samples collected over a 26-year period from patient H, a uniquely well-characterized, chronically infected individual. HCV pseudoparticles (HCVpp) expressing the patient-derived glycoproteins were generated and tested for their sensitivity to neutralization by autologous and heterologous serum antibodies. RESULTS: A strain-specific nAb response developed early in infection (8 weeks postinfection), whereas cross-reactive antibodies able to neutralize HCVpp-bearing heterologous glycoproteins developed late in infection (>33 wk postinfection). The humoral response continuously failed to neutralize viruses bearing autologous glycoprotein sequences that were present in the serum at a given time. The amplified glycoprotein sequences displayed high variability, particularly in regions corresponding to defined linear B-cell epitopes. Mutations in defined neutralizing epitopes were associated with a loss of recognition by monoclonal antibodies against these epitopes and with decreased neutralization of corresponding HCVpp. Viral escape from CD4 and CD8 T-cell responses also was shown for several novel epitopes throughout the glycoprotein region. CONCLUSIONS: During chronic infection HCV is subjected to selection pressures from both humoral and cellular immunity, resulting in the continuous generation of escape variants. We have analyzed the unique epitope for the broadly neutralizing human monoclonal antibody (MAb) 2G12 on the gp120 surface glycoprotein of human immunodeficiency virus type 1 (HIV-1). Sequence analysis, focusing on the conservation of relevant residues across multiple HIV-1 isolates, refined the epitope that was defined previously by substitutional mutagenesis (A. Trkola, M. Purtscher, T. Muster, C. Ballaun, A. Buchacher, N. Sullivan, K. Srinivasan, J. Sodroski, J. P. Moore, and H. Katinger, J. Virol. 70:1100-1108, 1996). In a biochemical study, we digested recombinant gp120 with various glycosidase enzymes of known specificities and showed that the 2G12 epitope is lost when gp120 is treated with mannosidases. Computational analyses were used to position the epitope in the context of the virion-associated envelope glycoprotein complex, to determine the variability of the surrounding surface, and to calculate the surface accessibility of possible glycan- and polypeptide-epitope components. Together, these analyses suggest that the 2G12 epitope is centered on the high-mannose and/or hybrid glycans of residues 295, 332, and 392, with peripheral glycans from 386 and 448 on either flank. The epitope is mannose dependent and composed primarily of carbohydrate, with probably no direct involvement of the gp120 polypeptide surface. It resides on a face orthogonal to the CD4 binding face, on a surface proximal to, but distinct from, that implicated in coreceptor binding. Its conservation amidst an otherwise highly variable gp120 surface suggests a functional role for the 2G12 binding site, perhaps related to the mannose-dependent attachment of HIV-1 to DC-SIGN or related lectins that facilitate virus entry into susceptible target cells. More than 20.8 million people are infected with HIV in sub-Saharan Africa, with South Africa having one of the fastest growing HIV-1 epidemics, where an estimated 2.4 million people were infected. Thirty-two sera from 25 patients were tested for their ability to neutralize HTLV-IIIB (IIIB) and four primary isolates representing subtypes B, C, D, and a recombinant gag C/env B type. A CEM-SS cell line-based assay was used and the neutralizing titer was defined as the reciprocal of the highest dilution giving a 50% reduction in p24 antigen production. All isolates were neutralized better by subtype-specific sera, except for the C4714 strain, which was neutralized by both subtype B and C sera. C4714 was neutralized by 18/25 (72%) sera, IIIB by 19/32 (59%) sera, D482 by 7/31(23%) sera, B3245 by 6/29 (21%) sera, and the recombinant B/C1491 isolate by 4/25 (16%) sera. Five sera were unable to neutralize any of the isolates. The V3 region of the isolates used in the neutralization assay was amplified by PCR, directly sequenced, and analyzed to reveal variability between the consensus HIV-1 sequences and the isolates. HIV-1 strain C4714 was neutralized more effectively with the sera tested than the IIIIB laboratory strain. Variability in the amino acid sequence of the V3 region, which can alter the conformation of the V3 loop secondary structure, can influence the neutralization of a particular viral isolate. Vaccine formulations should be broadened to include multiple subtypes, especially C subtypes, which is rapidly spreading worldwide. The rickettsial pathogen Anaplasma marginale expresses a variable immunodominant outer membrane protein, major surface protein 2 (MSP2), involved in antigenic variation and long-term persistence of the organism in carrier animals. MSP2 contains a central hypervariable region of about 100 amino acids that encodes immunogenic B-cell epitopes that induce variant-specific antibodies during infection. Previously, we have shown that MSP2 is encoded on a polycistronic mRNA transcript in erythrocyte stages of A. marginale and defined the structure of the genomic expression site for this transcript. In this study, we show that the same expression site is utilized in stages of A. marginale infecting tick salivary glands. We also analyzed the variability of this genomic expression site in Oklahoma strain A. marginale transmitted from in vitro cultures to cattle and between cattle and ticks. The structure of the expression site and flanking regions was conserved except for sequence that encoded the MSP2 hypervariable region. At least three different MSP2 variants were encoded in each A. marginale population. The major sequence variants did not change on passage of A. marginale between culture, acute erythrocyte stage infections, and tick salivary glands but did change during persistent infections of cattle. The variant types found in tick salivary glands most closely resembled those present in bovine blood at the time of acquisition of infection, whether infection was acquired from an acute or from a persistent rickettsemia. These variations in structure of an expression site for a major, immunoprotective outer membrane protein have important implications for vaccine development and for obtaining an improved understanding of the mechanisms of persistence of ehrlichial infections in humans, domestic animals, and reservoir hosts. Five murine epitopes were defined and mapped within IgA1 protease produced by Neisseria meningitidis. Epitopes 1 and 2 were present in IgA1 protease from all strains, and from Neisseria gonorrhoeae. Epitopes 3 through to 5 varied between subgroups of serogroup A meningococci, but have remained constant over decades within the subgroups, except for epitope 4, which changed between 1983 and 1987 during the spread of subgroup III meningococci from Asia to Africa. Binding of monoclonal antibodies to epitopes 1, 4 and 5 neutralized enzymatic function. Human sera containing antibodies to IgA1 protease as a result of natural infection inhibited binding of monoclonal antibodies to epitope 4 but not to the other epitopes. The envelope glycoprotein of small ruminant lentiviruses (SRLV) is a major target of the humoral immune response and contains several linear B-cell epitopes. We amplified and sequenced the genomic segment encoding the SU5 antigenic site of the envelope glycoprotein of several SRLV field isolates. With synthetic peptides based on the deduced amino acid sequences of SU5 in an enzyme-linked immunosorbent assay (ELISA), we have (i) proved the immunodominance of this region regardless of its high variability, (ii) defined the epitopes encompassed by SU5, (iii) illustrated the rapid and peculiar kinetics of seroconversion to this antigenic site, and (iv) shown the rapid and strong maturation of the avidity of the anti-SU5 antibody. Finally, we demonstrated the modular diagnostic potential of SU5 peptides. Under Swiss field conditions, the SU5 ELISA was shown to detect the majority of infected animals and, when applied in a molecular epidemiological context, to permit rapid phylogenetic classification of the infecting virus. |
393 | Is the transcriptional regulator BACH1 an activator or a repressor? | BACH1, a basic leucine zipper mammalian transcriptional repressor, negatively regulates heme oxygenase 1 (HMOX1), a key cytoprotective enzyme that has antioxidant and anti-inflammatory activities. In the absence of elevated intracellular heme or oxidative stress, BACH1 functions as a repressor of the enhancers of heme oxygenase-1 (HO-1) gene (Hmox-1) by forming heterodimers with the small Maf proteins such as MafK. Bach1 is recruited to a subset of p53 target genes and contributes to impeding p53 action by promoting histone deacetylation. | [19591297, 12356737, 16487043, 16824198, 20345481, 17682061, 19897490, 17942419, 16894358, 21812759, 15464985, 20501657, 22289179, 14660636, 11530014, 24035498, 17701549, 19119918, 21982894, 15809329, 19011633, 22127667, 20127796, 14580148, 22107958, 18426999, 15743416, 16530877, 21555518, 23446334, 23738048, 21473739, 15855052, 22735309, 16724942, 15734732, 11387216, 23562577, 12511571, 18555605, 21373270, 15068251, 20388958, 14504288, 19282658, 18325350, 15175654, 18948842, 15613547, 23181164, 19035757, 16771696, 17257585, 22698995, 23880309, 19439223, 22847612, 17901053, 18550526] | 500 | The tumor suppressor p53 induces cellular senescence, an irreversible form of proliferation arrest, to inhibit carcinogenesis as well as aging of organs and a body. While the major cause of cellular senescence and aging is oxidative stress, little is known about how the p53 activity is regulated under such conditions. Bach1 inhibits expression of oxidative stress responsive genes by competing with Nrf2, the key activator of oxidative stress response. Bach1 inhibits p53-dependent cellular senescence induced by oxidative stress. Bach1 forms a protein complex with p53, is recruited to p53 target genes, and inhibits their expression. These findings provide completely novel insights into how the activity of p53 is regulated under oxidative stress. Since p53 is the critical tumor suppressor with huge clinical implications, the newly identified mechanism should open new research fields. Heme oxygenase-1 (HO-1) protects cells from various insults including oxidative stress. Transcriptional activators, including the Nrf2/Maf heterodimer, have been the focus of studies on the inducible expression of ho-1. Here we show that a heme-binding factor, Bach1, is a critical physiological repressor of ho-1. Bach1 bound to the multiple Maf recognition elements (MAREs) of ho-1 enhancers with MafK in vitro and repressed their activity in vivo, while heme abrogated this repressor function of Bach1 by inhibiting its binding to the ho-1 enhancers. Gene targeting experiments in mice revealed that, in the absence of Bach1, ho-1 became expressed constitutively at high levels in various tissues under normal physiological conditions. By analyzing bach1/nrf2 compound-deficient mice, we documented antagonistic activities of Bach1 and Nrf2 in several tissues. Chromatin immunoprecipitation revealed that small Maf proteins participate in both repression and activation of ho-1. Thus, regulation of ho-1 involves a direct sensing of heme levels by Bach1 (by analogy to lac repressor sensitivity to lactose), generating a simple feedback loop whereby the substrate effects repressor-activator antagonism. Bach1 is a transcriptional repressor of heme oxygenase-1 gene (Hmox-1) and beta-globin gene. Heme oxygenase (HO)-1 is an inducible cytoprotective enzyme that degrades pro-oxidant heme to carbon monoxide (CO) and biliverdin/bilirubin, which are thought to mediate anti-inflammatory and anti-oxidant actions of HO-1. In the present study, we investigated the role of Bach1 in tissue protection against myocardial ischemia/reperfusion (I/R) injury in vivo using mice lacking the Bach1 gene (Bach1(-/-)) and wild-type (Bach1(+/+)) mice. In Bach1(-/-) mice, myocardial expression of HO-1 protein was constitutively up-regulated by 3.4-fold compared to that in Bach1(+/+) mice. While myocardial I/R induced HO-1 protein in ischemic myocytes in both strains of mice, the extent of induction was significantly greater in Bach1(-/-) mice than in Bach1(+/+) mice. Myocardial infarction was markedly reduced in size by 48.4% in Bach1(-/-) mice. Pretreatment of Bach1(-/-) mice with zinc-protoporphyrin, an inhibitor of HO activity, abolished the infarction-reducing effect of Bach1 disruption, indicating that reduction in the infarct size was mediated, at least in part, by HO-1 activity. Thus, Bach1 plays a pivotal role in setting the levels of both constitutive and inducible expression of HO-1 in the myocardium. Bach1 inactivation during I/R appears to be a key mechanism controlling the activation level of cytoprotective program involving HO-1. Heme oxygenase (HO)-1 has anti-oxidative, anti-inflammatory, and anti-apoptotic activities. However, little is known about the regulation of HO-1 in human primary acute myeloid leukemia (AML) cells. Here we investigated the expression of HO-1 in primary and established AML cells as well as other types of leukemic cells and normal monocytes, and its regulatory mechanism by the transcriptional repressor, BTB and CNC homology 1 (Bach1), and the activator, nuclear factor erythroid-derived 2 related factor 2 (Nrf2). Leukemic cell lines such as U937 expressed little HO-1, whereas most freshly isolated AML cells and monocytes expressed substantial amounts of HO-1, along with Bach1 and Nrf2. When U937 cells were treated with phorbol myristate acetate (PHA) or gamma-interferon, they significantly expressed both HO-1 and Bach1, like primary AML cells. Treatment with lipopolysaccharide (LPS) enhanced HO-1 expression in U937 cells but suppressed it in primary monocytes and PMA-treated U937 cells. In HO-1-expressing cells, Bach1 was localized in the cytoplasm, but Nrf2 was localized in the nuclei. Chromatin immunoprecipitation assay of these cells revealed the preferential binding of Nrf2 over Bach1 to Maf-recognition elements, the enhancer regions of the HO-1 gene. The downregulation of the HO-1 gene with siRNA increased a cytotoxic effect of an anticancer drug on primary AML cells, whereas the downregulation of Bach1 increased HO-1 expression, leading to enhanced survival. These and other results show that Bach1 plays a critical role in regulating HO-1 gene expression in AML cells and its expression suppresses their survival by downregulating HO-1 expression. Thus, functional upregulation of Bach1 is a potential strategy for antileukemic therapy. A central mechanism in cellular defence against oxidative or electrophilic stress is mediated by transcriptional induction of genes via the ARE (antioxidant-response element), a cis-acting sequence present in the regulatory regions of genes involved in the detoxification and elimination of reactive oxidants and electrophiles. The ARE binds different bZIP (basic-region leucine zipper) transcription factors, most notably Nrf2 (nuclear factor-erythroid 2-related factor 2) that functions as a transcriptional activator via heterodimerization with small Maf proteins. Although ARE activation by Nrf2 is relatively well understood, the mechanisms by which ARE-mediated signalling is down-regulated are poorly known. Transcription factor BACH1 [BTB (broad-complex, tramtrack and bric-a-brac) and CNC (cap'n'collar protein) homology 1] binds to ARE-like sequences, functioning as a transcriptional repressor in a subset of ARE-regulated genes, thus antagonizing the activator function of Nrf2. In the present study, we have demonstrated that BACH1 itself is regulated by Nrf2 as it is induced by Nrf2 overexpression and by Nrf2-activating agents in an Nrf2-dependent manner. Furthermore, a functional ARE site was identified at +1411 from the transcription start site of transcript variant 2 of BACH1. We conclude that BACH1 is a bona fide Nrf2 target gene and that induction of BACH1 by Nrf2 may serve as a feedback-inhibitory mechanism for ARE-mediated gene regulation. Bach1 is a member of the basic leucine zipper transcription factor family, and the Bach1/small Maf heterodimer specifically represses transcriptional activity directed by the Maf recognition element (MARE). Because Bach1 is a repressor of the oxidative stress response, we examined the function(s) of Bach1 in keratinocytes subjected to oxidative stress. Oxidative stress induced by H(2)O(2) led to an increase in MARE activity and expression of heme oxygenase-1 (HO-1), an inducible antioxidant defense enzyme. Bach1 depletion by small interfering RNAs or by deletion of Bach1 enhanced HO-1 expression in the absence of H(2)O(2), indicating that Bach1 is a critical repressor of HO-1 in keratinocytes. Although Bach1-deficient or -reduced keratinocytes expressed higher levels of HO-1 than control cells in response to H(2)O(2), Bach1 down-regulation did not attenuate the production of reactive oxygen species by H(2)O(2). In contrast, Bach1 overexpression abolished HO-1 induction by H(2)O(2), which led to increased reactive oxygen species accumulation. HO-1 was induced during keratinocyte differentiation, but MARE activity did not change during differentiation. Furthermore, Bach1 overexpression did not inhibit differentiation-associated induction of HO-1 expression, suggesting that HO-1 induction in differentiation is independent of Bach1. Thus, in response to oxidative stress, Bach1 regulates the oxidation state through the negative control of HO-1 expression prior to terminal keratinocyte differentiation. However, Bach1-mediated repression is negated during keratinocyte differentiation. The transcriptional repressor Bach1 mediates various stress responses. Despite its role in transcription, Bach1 is predominantly exported to the cytoplasm in a Crm1-dependent manner, but the functional role of its cytoplasmic retention is still unclear. We found that Bach1 was also excluded from mitotic chromatin by a C-terminal cytoplasmic localization sequence dependent and leptomycin B sensitive process. Bach1 depletion resulted in disordered mitotic chromosome alignment, which was rescued by Bach1 mutants lacking the BTB or DNA binding domains, suggesting its transcription-independent mechanism. We thus revealed a novel role of Bach1 in the regulation of mitotic chromosome dynamics. Modular cullin-RING E3 ubiquitin ligases (CRLs) use substrate binding adaptor proteins to specify target ubiquitylation. Many of the ~200 human CRL adaptor proteins remain poorly studied due to a shortage of efficient methods to identify biologically relevant substrates. Here, we report the development of parallel adaptor capture (PAC) proteomics and its use to systematically identify candidate targets for the leucine-rich repeat family of F-box proteins (FBXLs) that function with SKP1-CUL1-F-box protein (SCF) E3s. In validation experiments, we identify the unstudied F-box protein FBXL17 as a regulator of the NFR2 oxidative stress pathway. We demonstrate that FBXL17 controls the transcription of the NRF2 target HMOX1 via turnover of the transcriptional repressor BACH1 in the absence or presence of extrinsic oxidative stress. This work identifies a role for SCF(FBXL17) in controlling the threshold for NRF2-dependent gene activation and provides a framework for elucidating the functions of CRL adaptor proteins. The mammalian transcription factor Bach1 functions as a repressor of the enhancers of heme oxygenase-1 (HO-1) gene (Hmox-1) by forming heterodimers with the small Maf proteins such as MafK. The transcription of Hmox-1 is regulated by the substrate of HO-1, heme. Heme induces expression of Hmox-1 in part by inhibiting the binding of Bach1 to the enhancers and inducing the nuclear export of Bach1. A dipeptide motif of cysteine and proline (CP motif) in Bach1 is essential for the heme-mediated regulation. In this study, we show that five molecules of heme bind to Bach1 by the heme-titration assay. The Bach1-heme complex exhibits an absorption spectrum with a major Soret peak at 371 nm and Raman band at 343 cm(-1) in high amounts of heme and a spectrum containing the major Soret peak at 423 nm at low heme concentrations. The spectroscopic characterization indicates that Bach1 has two kinds of heme-binding sites with different coordination structures. Mutagenesis studies have established that four molecules of heme bind to the cysteine residues of four CP motifs in the C terminus of Bach1. These results raise the possibility that two separated activities of Bach1, DNA-binding and nuclear export, are regulated by heme binding at the different CP motifs of Bach1 respectively, but not by cooperative heme-binding. Bach1 functions as a transcriptional repressor of heme oxygenase-1 (HO-1) and the beta-globin genes. The enhancer regions of these genes contain multiple Maf recognition elements (MAREs) to which Bach1 can bind. Previous studies have shown that increased levels of heme and cadmium induce the nuclear export of Bach1, resulting in cytoplasmic accumulation. By means of a yeast two hybrid screening using Bach1 as bait, we identified the intracellular hyaluronic acid binding protein (IHABP) as a potential regulator of Bach1. IHABP is a microtubule-associated protein that may regulate the organization of the cytoskeletal network. A series of domain analyses revealed that a region of Bach1 previously implicated in cytoplasmic accumulation was necessary for IHABP-binding. A C-terminal region of IHABP was necessary for Bach1-binding. Overexpressed Bach1 colocalized with IHABP in the cytoplasm, forming fiber-like structures on microtubules. Fluorescence recovery after photobleaching (FRAP) analysis revealed a dynamic nature of the Bach1-IHABP interaction in living cells. The repression of HO-1 reporter activity by Bach1 was attenuated by co-transfecting IHABP in a dose-dependent manner. Moreover, the overexpression of IHABP induced the endogenous HO-1 gene in NIH3T3 cells. The overall results suggest that IHABP regulates the subcelluar localization of Bach1 in order to fine-tune transactivation of Bach1 target genes such as HO-1. Cellular senescence is one of the key strategies to suppress expansion of cells with mutations. Senescence is induced in response to genotoxic and oxidative stress. Here we show that the transcription factor Bach1 (BTB and CNC homology 1, basic leucine zipper transcription factor 1), which inhibits oxidative stress-inducible genes, is a crucial negative regulator of oxidative stress-induced cellular senescence. Bach1-deficient murine embryonic fibroblasts showed a propensity to undergo more rapid and profound p53-dependent premature senescence than control wild-type cells in response to oxidative stress. Bach1 formed a complex that contained p53, histone deacetylase 1 and nuclear co-repressor N-coR. Bach1 was recruited to a subset of p53 target genes and contributed to impeding p53 action by promoting histone deacetylation. Because Bach1 is regulated by oxidative stress and heme, our data show that Bach1 connects oxygen metabolism and cellular senescence as a negative regulator of p53. Hepatitis C virus (HCV) directly induces oxidative stress and liver injury. Bach1, a basic leucine zipper mammalian transcriptional repressor, negatively regulates heme oxygenase 1 (HMOX1), a key cytoprotective enzyme that has antioxidant and anti-inflammatory activities. microRNAs (miRNAs) are small noncoding RNAs ( approximately 22 nt) that are important regulators of gene expression. Whether and how miRNAs regulate Bach1 or HCV are largely unknown. The aims of this study were to determine whether miR-196 regulates Bach1, HMOX1, and/or HCV gene expression. HCV replicon cell lines (Con1 and 9-13) of the Con1 isolate and J6/JFH1-based HCV cell culture system were used in this study. The effects of miR-196 mimic on Bach1, HMOX1, and HCV RNA, and protein levels were measured by way of quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting, respectively. The Dual Glo Luciferase Assay System was used to determine reporter activities. miR-196 mimic significantly down-regulated Bach1 and up-regulated HMOX1 gene expression and inhibited HCV expression. Dual luciferase reporter assays demonstrated that transfection of miR-196 mimic resulted in a significant decrease in Bach1 3'-untranslated region (UTR)-dependent luciferase activity but not in mutant Bach1 3'-UTR-dependent luciferase activity. Moreover, there was no detectable effect of mutant miR-196 on Bach1 3'-UTR-dependent luciferase activity. CONCLUSION: miR-196 directly acts on the 3'-UTR of Bach1 messenger RNA and translationally represses the expression of this protein, and up-regulates HMOX1. miR-196 also inhibits HCV expression in HCV replicon cell lines (genotype 1b) and in J6/JFH1 (genotype 2a) HCV cell culture system. Thus, miR-196 plays a role in both HMOX1/Bach1 expression and the regulation of HCV expression in human hepatocytes. Overexpression of miR-196 holds promise as a potential novel strategy to prevent or ameliorate hepatitis C infection, and to protect against liver injury in chronic HCV infection. Heme must be synthesized and degraded within an individual nucleated cell. Heme degradation is catalyzed by the two isozymes of heme oxygenase, heme oxygenase-1 (HO-1) and HO-2, eventually yielding biliverdin/bilirubin, CO, and iron. These products possess important physiological roles but are potentially toxic to cells. Characteristically, human HO-1 contains no Cys residues, whereas HO-2 contains the potential heme-binding motifs of the Cys-Pro dipeptide. Expression of HO-1 is inducible or repressible, depending on cell types or cellular microenvironments, but expression levels of HO-2 are fairly constant. Thus, the main regulation of heme catabolism is a problem of the balance between induction and repression of HO-1. Notably, HO-1 expression is induced by heme in all mammalian cells examined, but is repressed by hypoxia in certain types of cultured human cells. The recent discovery of Bach1 as a heme-regulated and hypoxia-inducible repressor for transcription of the HO-1 gene has provided a missing link in the feedback control of heme catabolism. On the other hand, the human HO-1 gene promoter contains the (GT)n repeat polymorphism and a single nucleotide polymorphism (-427A --> T), both of which may contribute to fine-tuning of the transcription. Importantly, long (GT)n alleles are associated with susceptibility to smoking-induced emphysema or coronary artery disease, but may provide with resistance to cerebral malaria. The latter finding suggests a novel therapeutic strategy with inhibitors of HO-1 for the treatment of cerebral malaria. We discuss the potential regulatory role of Bach1 and HO-2 in heme catabolism and update the understanding of the regulation of HO-1 expression. Up-regulation of heme oxygenase 1 (HO-1) by ultraviolet A (UVA; 320-380 nm) irradiation of human skin cells protects them against oxidative stress. The role of Nrf2 in up-regulation of HO-1 and other phase II genes is well established. The mechanism underlying Bach1-mediated HO-1 repression is less well understood although cellular localization seems to be crucial. Because prolonged HO-1 overexpression is likely to be detrimental, it is crucial that activation of the gene is transient. We now show that UVA irradiation of cultured human skin fibroblasts enhances accumulation of Bach1 mRNA and protein severalfold. Endogenous Bach1 protein accumulates in the nucleus after 8h and may occupy MARE sites after HO-1 activation thus providing a compensatory mechanism to control HO-1 overexpression. Overexpression of Bach1, together with MafK, represses basal and UVA-mediated HO-1 protein expression, whereas silencing of the Bach1 gene by Bach1-specific siRNAs causes robust enhancement of constitutive HO-1 levels. UVA treatment of cells in which Bach1 has been silenced leads to higher levels of induction of the HO-1 protein. Although Bach1 protein is exported from the nucleus 12h after UVA irradiation, the release of free cellular heme from microsomal heme-containing proteins is immediate rather than delayed. Although heme does promote the export of Bach1 via the Crm1/exportin 1 pathway and is involved in the delayed UVA-mediated export of the protein, it is not clear how this occurs. Bach1 is a stress-responsive transcriptional factor that is thought to control the expression levels of cytoprotective factors, including heme-oxygenase (HO)-1. In the present study, we investigated the roles of Bach1 in the development of left ventricular (LV) hypertrophy and remodeling induced by transverse aortic constriction (TAC) in vivo using Bach1 gene-deficient (Bach1(-/-)) mice. TAC for 3 weeks in wild-type control (Bach1(+/+)) mice produced LV hypertrophy and remodeling manifested by increased heart weight, histological findings showing increased myocyte cross-sectional area (CSA) and interstitial fibrosis (picro Sirius red staining), reexpressions of ANP, BNP, and betaMHC genes, and echocardiographic findings showing wall thickening, LV dilatation, and reduced LV contraction. Deletion of Bach1 caused significant reductions in heart weight (by 16%), CSA (by 36%), tissue collagen content (by 38%), and gene expression levels of ANP (by 75%), BNP (by 45%), and betaMHC (by 74%). Echocardiography revealed reduced LV dimension and ameliorated LV contractile function. Deletion of Bach1 in the LV caused marked upregulation of HO-1 protein accompanied by elevated HO activity in both basal or TAC-stimulated conditions. Treatment of Bach1(-/-) mice with tin-protoporphyrin, an inhibitor of HO, abolished the antihypertrophic and antiremodeling effects of Bach1 gene ablation. These results suggest that deletion of Bach1 caused upregulation of cytoprotective HO-1, thereby inhibiting TAC-induced LV hypertrophy and remodeling, at least in part, through activation of HO. Bach1 repressively controls myocardial HO-1 expression both in basal and stressed conditions, inhibition of Bach1 may be a novel therapeutic strategy to protect the myocardium from pressure overload. Bach1 is a transcriptional repressor of the cytoprotective enzyme heme oxygenase-1 (HO-1). Although HO-1 protects against atherosclerosis, the function of Bach1 in this process is poorly understood. We isolated peritoneal macrophages and aortic smooth muscle cells (SMC) from wild-type and bach1-deficient mice. bach1-Deficient macrophages expressed increased levels of HO-1 and showed elevated phagocytic activity when incubated with 0.75 microm microspheres. In SMC, bach1-ablation resulted in increased expression of HO-1 and decreased proliferation in bromodeoxyuridine incorporation assay as compared with wild-type cells. The up-regulated phagocytic activity and reduced SMC proliferation of bach1-deficient cells were not restored by Zinc (II) protoporphyrin IX, an inhibitor of HO, suggesting that HO-independent mechanisms are also involved in the regulation of phagocytosis of macrophages and proliferation of SMC by Bach1. In wild-type mice, cuff placement around femoral artery caused pronounced intimal proliferation without affecting the media, thus resulting in intimal to medial (I/M) volume ratio of 65.6%. bach1-deficient mice had less degree of intimal growth (I/M ratio of 45.6%). These results indicate that Bach1 plays a critical role in the regulation of HO-1 expression, macrophage function, SMC proliferation and neointimal formation. Bach1 may regulate gene expression in these cells during inflammation and atherogenesis. BACKGROUND/AIMS: Hepatitis C infection induces hepatic oxidative stress. Heme oxygenase (HO), the rate-controlling enzyme of heme catabolism, plays a key role as a protector against oxidative, and other stresses. Other recent work has implicated Bach1, a heme binding protein that represses gene expression, in the regulation of HO-1 gene expression. METHODS: We investigated the effects of HCV polyprotein expression on expression of HO-1 and Bach1 genes in human hepatoma cells (Huh-7 cells). RESULTS: HO-1 was up-regulated in the cell line expressing HCV proteins from core up to the aminoterminal domain of NS3. Addition of increasing concentrations of N-acetylcysteine (NAC) led to down-regulation of HO-1 in cells expressing HCV proteins. In contrast, Bach1 was significantly down-regulated in these cells. Sodium arsenite, a strong inducer of oxidative stress and HO-1, reduced Bach1 expression in wild type Huh-7 cells, and NAC partially abrogated this decrease. CONCLUSIONS: Huh-7 cells expressing HCV proteins show significant up-regulation of the HO-1 gene, and reciprocal down-regulation of the Bach1 gene. Exogenous oxidative stressors and anti-oxidants can modulate expression of these genes. These and other results suggest a key role of down-regulation of Bach1 and up-regulation of HO-1 in diminishing cytotoxic effects of HCV proteins in human hepatocytes. The regulation of gene expression in response to environmental signals and metabolic imbalances is a key step in maintaining cellular homeostasis. BTB and CNC homology 1 (BACH1) is a heme-binding transcription factor repressing the transcription from a subset of MAF recognition elements at low intracellular heme levels. Upon heme binding, BACH1 is released from the MAF recognition elements, resulting in increased expression of antioxidant response genes. To systematically address the gene regulatory networks involving BACH1, we combined chromatin immunoprecipitation sequencing analysis of BACH1 target genes in HEK 293 cells with knockdown of BACH1 using three independent types of small interfering RNAs followed by transcriptome profiling using microarrays. The 59 BACH1 target genes identified by chromatin immunoprecipitation sequencing were found highly enriched in genes showing expression changes after BACH1 knockdown, demonstrating the impact of BACH1 repression on transcription. In addition to known and new BACH1 targets involved in heme degradation (HMOX1, FTL, FTH1, ME1, and SLC48A1) and redox regulation (GCLC, GCLM, and SLC7A11), we also discovered BACH1 target genes affecting cell cycle and apoptosis pathways (ITPR2, CALM1, SQSTM1, TFE3, EWSR1, CDK6, BCL2L11, and MAFG) as well as subcellular transport processes (CLSTN1, PSAP, MAPT, and vault RNA). The newly identified impact of BACH1 on genes involved in neurodegenerative processes and proliferation provides an interesting basis for future dissection of BACH1-mediated gene repression in neurodegeneration and virus-induced cancerogenesis. Previous studies have proved that the environmental toxicant, inorganic arsenic, activates nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in many different cell types. This study tried to explore the hepatic Nrf2 pathway upon arsenic treatment comprehensively, since liver is one of the major target organs of arsenical toxicity. Our results showed that inorganic arsenic significantly induced Nrf2 protein and mRNA expression in Chang human hepatocytes. We also observed a dose-dependent increase of antioxidant response element- (ARE-) luciferase activity. Both the mRNA and protein levels of NAD(P)H:quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1) were all upregulated dramatically. On the other hand, entry and accumulation of Nrf2 protein in the nucleus, while exportting the transcriptional repressor BTB and CNC homology 1 (Bach1) from nucleus to cytoplasm, were also confirmed by western blot and immunofluorescence assay. Our results therefore confirmed the arsenic-induced Nrf2 pathway activation in hepatocytes and also suggested that the translocation of Bach1 was associated with the regulation of Nrf2 pathway by arsenic. Hepatic Nrf2 pathway plays indispensable roles for cellular defenses against arsenic hepatotoxicity, and the interplay of Bach1 and Nrf2 may be helpful to understand the self-defensive responses and the diverse biological effects of arsenicals. Phenylpropanoids have several highly significant biological properties in both plants and animals. Four phenylpropanoid glycosides (PPGs), verbascoside (VB), forsythoside B (FB), echinacoside (EC) and campneoside I (CP), were purified and tested for their capability to activate NRF2 and induce phase II cytoprotective enzymes in a human keratinocyte cell line (HaCaT). All four substances showed similar strong antioxidant and radical-scavenging activities as determined by diphenylpicrylhydrazyl assay. Furthermore, in HaCaT cells, FB and EC are strong activators of NRF2, the nuclear transcription factor regulating many phase II detoxifying and cytoprotective enzymes, such as heme oxygenase 1 (HMOX1). In HaCaT cells, FB and EC (200 μM) induced nuclear translocation of NRF2 protein after 24 h and reduced nuclear protein levels of BACH1, a repressor of the antioxidant response element. FB and EC greatly HMOX1 mRNA levels by more than 40-fold in 72 h. Cytoplasmic HMOX1 protein levels were also increased at 48 h after treatment. VB was less active compared to FB and EC, and CP was slightly active only at later times of treatment. We suggest that hydroxytyrosol (HYD) could be a potential bioactive metabolite of PPGs since HYD, in equimolar amounts to PGGs, is able to both activate HO-1 transcription and modify Nrf2/Bach1 nuclear protein levels. This is in agreement with the poor activity of CP, which contains a HYD moiety modified by an O-methyl group. In conclusion, FB and EC from plant cell cultures may provide long-lasting skin protection by induction of phase II cytoprotective capabilities. Oxidative stress is involved in the mechanism of atherosclerotic lesion formation and in the mechanisms underlying the development of other pathogenic conditions of the cardiovascular system, including endothelial dysfunction, hypertension, and heart failure. Reducing oxidative stress may be a reasonable therapeutic approach to treat cardiovascular diseases. HO-1 is a cytoprotective enzyme that is induced in response to oxidative stress and degrades heme into carbon monoxide (CO) and bilirubin, both of which have cytoprotective effects. A substantial body of evidence suggests that introduction of HO-1, either pharmacologically or by a gene delivery technique, confers cytoprotection in ischemic heart disease and atherosclerosis in animals. Recent studies have revealed that CO has anti-inflammatory properties and that administration of CO provides protection against atherosclerosis and ischemic heart disease. Discovery of Bach1, a transcriptional repressor of HO-1, has greatly contributed to the understanding of the regulation of HO-11 expression, providing a clue to a development of alternative method to enhance HO activity. Bach1 normally represses HO-1 expression. However, upon exposure to oxidative stress, Bach1 loses its repressive activity and is exported out of the nucleus, which in turn results in the upregulation of HO-1. Bach1 knockout mice, expressing an increased amount of HO-1, are resistant to pro-atherosclerotic and ischemic stresses. These findings indicate that inhibition of Bach1 may be a novel approach to enhance protection against stress. In summary, the Bach1-HO-1 system is an important defense mechanism against oxidative stress. Development of a safe and effective method to enhance this pathway, such as Bach1 inhibitor, may be of great clinical relevance. The antioxidant response element (ARE) and Nrf2 are known to regulate the expression and coordinated induction of genes encoding detoxifying enzymes including NAD(P)H:quinone oxidoreductase1 (NQO1) in response to antioxidants. In this report, we demonstrate that overexpression of the transcription factor Bach1 in Hep-G2 cells negatively regulated NQO1 gene expression and induction in response to antioxidant t-BHQ. Bandshift and supershift assays revealed that Bach1 binds to the ARE as a heterodimer with small Maf proteins but not as a homodimer or heterodimer with Nrf2. The transfection and ChIP assays revealed that Bach1 and Nrf2 competed with each other to regulate ARE-mediated gene expression. Heme, a negative regulator of Bach1 relieved the Bach1 repression of NQO1 gene expression in transfected cells. The transcription of Bach1 and Nrf2 did not change in response to t-BHQ. Immunofluorescence assays and Western blot analysis revealed that both Bach1 and Nrf2 localized in the cytoplasm and nucleus of the untreated cells. The treatment of cells with t-BHQ resulted in the nuclear accumulation of both Bach1 and Nrf2. Interestingly, the t-BHQ-induced nuclear accumulation of Bach1 was significantly delayed over that of Nrf2. These results led to the conclusion that a balance of Nrf2 versus Bach1 inside the nucleus influences up- or down-regulation of ARE-mediated gene expression. The results further suggest that antioxidant-induced delayed accumulation of Bach1 contributes to the down-regulation of ARE-regulated genes, presumably to reduce the antioxidant enzymes to normal levels. Heme oxygenase 1 (HO-1) catalyzes heme breakdown, eventually releasing iron, carbon monoxide, and bilirubin IXalpha. HO-1 is induced by its substrate heme and various environmental factors, which represents a protective response against oxidative stresses. Here we show that hypoxia represses HO-1 expression in three human cell types but induces it in rat, bovine, and monkey cells, indicating the inter-species difference in the hypoxic regulation of HO-1 expression. The hypoxia-mediated repression of HO-1 expression is consistently associated with the induction of Bach1, a heme-regulated transcriptional repressor, in human cells. Bach1 is a basic leucine zipper protein, forming a heterodimer with a small Maf protein. Expression of HO-1 was also reduced in human cells when exposed to interferon-gamma or an iron chelator desferrioxamine, each of which induced Bach1 expression. In contrast, induction of HO-1 expression by CoCl(2) is associated with reduced expression of Bach1 mRNA. Thus, expression of HO-1 and Bach1 is inversely regulated. We have identified a Maf recognition element in the human HO-1 gene that is required for repression of a reporter gene by hypoxia and targeted by Bach1. Therefore, Bach1 functions as a hypoxia-inducible repressor for the HO-1 gene, thereby contributing to fine-tuning of oxygen homeostasis in human cells. Oxidative stress has been implicated in tissue damage from traumatic brain injury. Heme oxygenase-1 (HO-1) is an inducible enzyme that degrades prooxidant heme to radical-scavenging biliverdin/bilirubin in order to protect cells from oxidative stress. Although HO-1 is induced after induction of brain damage, the regulatory mechanism of HO-1 in the brain is still unclear. Bach1 is a transcriptional repressor of the HO-1 gene, and plays a critical role in tissue protection from oxidative stress by reperfusion injury of the myocardium. In this study, we examined the role of Bach1 in HO-1 regulation of the various brain sites by investigating the expression of Bach1 and HO-1 in brain tissues of mice bearing Bach1-deficient (Bach1(-/-)) or wild-type (Bach1(+/+)) genes. While the expression levels of Bach1 mRNA in the olfactory bulb were significantly higher than other brain areas, those at the cortex showed the lowest activity. Bach1(-/-) mice showed significantly higher HO-1 mRNA expression levels than Bach1(+/+) mice in all brain sites studied. Moreover, higher induction of HO-1 was observed around damaged tissues after cold injury in Bach1(-/-) than Bach1(+/+) mice. Thus, Bach1 plays an important role in regulating the constitutive and inducible expression levels of HO-1 in the brain. Although a significantly higher level of HO-1 was observed in Bach1(-/-) than Bach1(+/+) mice, genetic ablation of the Bach1 gene failed to show any tissue protective effect after cold injury was inflicted on the cortex. Bach1 is a transcriptional repressor of heme oxygenase-1 (HO-1, a.k.a. HSP-32), which is an inducible enzyme and has anti-oxidation/anti-inflammatory properties shown in various models of organ injuries. Since oxidative stress plays a pivotal role in the pathogenesis of nonalcoholic steatohepatitis (NASH), HO-1 induction would be expected to prevent the development of NASH. In this study, we investigated the influence of Bach1 ablation in mice on the progression of NASH in methionine-choline deficient (MCD) diet model. Bach1 ablation resulted in significant induction of HO-1 mRNA and its activity in the liver. When fed MCD diet, Bach1(-/-) mice exhibited negligible hepatic steatosis compared to pronounced steatohepatitis in wild type mice with 6-fold increase in hepatic triglyceride content. Whereas feeding of MCD diet decreased mRNA expressions of peroxisome proliferator-activated receptor (PPAR) α and microsomal triglyceride transfer protein (MTP) in wild type mice, there were no change in Bach1(-/-) mice. In addition, hepatic concentration of malondialdehyde (MDA), a biomarker for oxidative stress as well as plasma alanine aminotransferase (ALT) was significantly lower in Bach1(-/-) mice. These findings suggest that Bach1 ablation exerts hepatoprotective effect against steatohepatitis presumably via HO-1 induction and may be a potential therapeutic target. BTB and CNC homolog 1 (Bach1) is a transcriptional repressor of heme oxygenase-1 (HO-1). It plays an important role in the feedback regulation of HO-1 expression, which protects cells from various insults including oxidative stress and inflammatory cytokines. However, the role of Bach1 in intestinal inflammation remains unclear. In this study, the role of Bach1 in intestinal mucosal injury was elucidated using 8-week-old female C57BL/6 (wild-type) and homozygous Bach1-deficient C57BL/6 mice. Intestinal mucosal injuries induced by a single subcutaneous administration of indomethacin were evaluated macroscopically, histologically, and biochemically. Mucosal protein content and chemokine mRNA levels were determined by real-time PCR. Our results showed that the indomethacin-induced intestinal injury was remarkably improved in Bach1-deficient mice. Histological examination showed that the area of injured lesion was decreased in Bach1-deficient mice compared to wild-type mice. Administration of indomethacin induced expression of inflammatory chemokines such as KC, MIP1alpha and MCP1, which was suppressed in Bach1-deficient mice. Myeloperoxidase activity in the intestinal mucosa was also significantly decreased in Bach1-deficient mice. Additionally, Bach1 deficiency enhanced immunopositivity of HO-1 in the intestinal mucosa after indomethacin administration. Disruption of the Bach1 gene thus caused inhibition of mucosal injury, indicating that inhibition of Bach1 may be a novel therapeutic strategy for treating indomethacin-induced intestinal injury. The export of certain nuclear proteins is involved in the regulation of various nuclear functions, including transcription. In some cases, the export of target proteins is induced upon environmental or cellular cues, resulting in conditional gene expression. The small Maf proteins appear to be critical regulators of heme oxygenase (HO)-1, an anti-oxidant defense enzyme that degrades heme into iron, carbon monoxide, and biliverdin. Although ho-1 is repressed by Bach1/small Maf heterodimers, it is activated by Nrf2/small Maf heterodimers, indicating that Bach1 and Nrf2 compete with each other. We anticipated that the nuclear concentration of Bach1 might be regulated to ensure that the entire system effectively responds to various stimuli. We carried out detailed domain analysis of Bach1 in an effort to understand how various inducers of HO-1 inactivate Bach1. We show here that cadmium, a strong inducer of HO-1, activates the nuclear export of Bach1. This cadmium-induced export of Bach1 was mediated in trans by its C-terminal region that is conserved between Bach1 and Bach2. The nuclear export of Bach2 was also induced by cadmium, indicating that the cadmium responsibility is shared between Bach1 and Bach2. The nuclear export of Bach1 was dependent on Crm1/Exportin-1 as well as the extracellular signal-regulated kinase-1/2 (ERK1/2) activity. These results indicate that the nuclear export of Bach1 constitutes an important regulatory mechanism to relieve the Bach1-mediated repression of genes such as ho-1. Bach1 is a basic region-leucine zipper (bZip) protein that forms heterodimers with the small Maf proteins and functions as a repressor of gene expression. One of the target genes of Bach1 is Hmox-1 that encodes heme oxygenase-1 (HO-1). HO-1 degrades heme into carbon monoxide (CO), biliverdin, and iron. HO-1 is strongly induced by various stresses as well as its substrate heme, and protects cells and tissues against insults through diverse cytoprotective functions of the reaction products CO and biliverdin. Bach1-deficiency in mice leads to higher expression of Hmox-1 in various tissues. Here we investigated the effects of Bach1-deficiency in mice on tissue injuries: hepatic injury induced by D-galactosamine (GalN) and lipopolysaccharide (LPS), and mouse paw edema induced by carrageenin, polysaccharide derived from various seaweeds. Bach1-deficiency suppressed induction of plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in response to the GalN/LPS-treatment. However, production of tumor necrosis factor alpha (TNF-alpha) and nitric oxide (NO), both being cytotoxic mediators in LPS-induced hepatic injury, in Bach1-deficient mice and their peritoneal macrophages was similar to wild type controls. In contrast, Bach1-deficiency did not affect extent of mouse paw edema induced by carrageenin, which enhances vascular permeability by activating kinin release. These results indicate that Bach1 plays an inhibitory role in the cytoprotection of LPS-induced liver injury but not in the kinin-mediated inflammatory edema. The inhibitory role for Bach1 may stem from its activity to repress gene expression including HO-1. Heme oxygenase-1 (HO-1), the rate-limiting enzyme of heme degradation and antioxidant defense protein, is induced in the lungs of animals exposed to hyperoxia. However, high levels of HO-1 expression may be deleterious, thus necessitating tight regulation. Previous reports show maturational differences in rat HO-1 regulation in hyperoxia, as newborns do not up-regulate HO-1mRNA compared with adults. To better understand the differential response of lung HO-1 to hyperoxia, we exposed newborn and adult mice to >95% oxygen. The newborn lungs had reduced HO-1 mRNA induction compared with adults and newborn transgenic mice over-expressing luciferase driven by the 15 kb HO-1 promoter (HO-1/Luc Tg) had less increased light emission in hyperoxia compared with adults. Compared with adults, levels of the repressor of HO-1 transcription, Bach1, were higher in the neonatal lung as was nuclear protein-DNA binding to the antioxidant response element (ARE) from HO-1. Furthermore, at baseline and in hyperoxia, chromatin immunoprecipitation (ChIP) revealed increased Bach1 binding to the HO-1 distal enhancers (DEs) in the neonates compared with adults. These data suggest that elevated levels of Bach1 may help to limit HO-1 induction in the newborn at baseline and in response to oxidative stress. Both nuclear factor erythroid 2 45 kDa subunit (p45) and BTB and CNC homolog 1 (Bach) transcription factors can form dimers with one of the small Maf proteins, and these heterodimers bind to the musculoaponeurotic fibrosarcoma oncogene (Maf) recognition element (MARE). MARE is known to act as a critical cis-regulatory element of erythroid and megakaryocytic genes. Although detailed analyses of p45-null mutant mice and small maf compound mutant mice revealed that these factors are both critical for platelet production, the functional contributions of Bach1 and the relationship or redundancy between Bach1 and p45 in megakaryocytes remain to be clarified. To address these issues, we generated transgenic lines of mice bearing human BACH1 cDNA under the control of the GATA-1 locus hematopoietic regulatory domain. The transgenic mouse lines showed significant thrombocytopenia associated with impaired maturation of the megakaryocytes, and they developed myelofibrosis. The megakaryocytes in the transgenic mice exhibited reduced proplatelet formation, and the modal ploidy class of megakaryocytes was 2N, indicating the impairment of endomitosis. Transcription of the p45 target genes was down-regulated and we indeed found that BACH1 binds to the thromboxane synthase gene, one of the target genes for p45 in megakaryocytes. These findings thus provide evidence that BACH1 acts as a transcriptional repressor in the regulation of MARE-dependent genes in megakaryocytes. OBJECT: Oxidative stress contributes to secondary injury after spinal cord injury (SCI). The expression of heme oxygenase-1 (HO-1), which protects cells from various insults including oxidative stress, is upregulated in injured spinal cords. Mice deficient in Bach1 (Bach1-/-), a transcriptional repressor of the HO-1 and beta-globin genes, express high levels of HO-1 mRNA and protein in various organs. The authors hypothesized that HO-1 modulates the secondary injury process after SCI in Bach1(-/-) mice. METHODS: Male C57BL/6 (wild-type) and homozygous Bach1(-/-) C57BL/6 mice were subjected to moderate SCI, and differences in hindlimb motor function, and electrophysiological, molecular biological, and histopathological changes were assessed for 2 weeks. RESULTS: Functional recovery was greater, and motor evoked potentials were significantly larger in Bach1(-/-) mice than in wild-type mice throughout the observation period. The expression of HO-1 mRNA in the spinal cord was significantly increased in both mice until 3 days after injury, and it was significantly higher in Bach1(-/-) mice than in wild-type mice at every assessment point. Histological examination using Luxol fast blue staining at 1 day after injury showed that the injured areas were smaller in Bach1(-/-) mice than in wild-type mice. The HO-1 immunoreactivity was not detected in uninjured spinal cord, but 3 days postinjury the number of HO-1-immunoreactive cells was obviously higher in the injured area in both mice, particularly in Bach1(-/-) mice. The HO-1 was primarily induced in microglia/macrophage in both mice. CONCLUSIONS: These results suggest that HO-1 modulates the secondary injury process, and high HO-1 expression may preserve spinal cord function in the early stages after SCI in Bach1(-/-) mice. Treatment that induces HO-1 expression at these early stages may preserve the functional outcome after SCI. Tin mesoporphyrin (SnMP), a competitive heme oxygenase (HO) inhibitor, also induces HO-1 mRNA and protein expression by a mechanism that is not fully understood. We examined whether the induction by SnMP is mediated by a de-repression of Bach1, a transcription factor that suppresses the HO-1 gene. Incubation of NIH3T3-HO-1-luc cells with SnMP attenuated HO activity with a concomitant increase in HO-1 mRNA and protein and a decrease in Bach1 and HO-2 proteins, which was not due to transcriptional down-regulation, but accelerated protein decay. Similarly, HO-1 protein degradation was increased by SnMP, despite of an elevation in HO-1 transcription. Transfection of Bach1 shRNA in Hepa cells raised basal HO-1 expression significantly, and SnMP treatment further increased HO-1 mRNA. In conclusion, SnMP induces HO-1 expression not only by de-repressing the HO-1 promoter by binding Bach1, but also by accelerating Bach1 degradation. The let-7 microRNA (miRNA) plays important roles in human liver development and diseases such as hepatocellular carcinoma, liver fibrosis and hepatitis wherein oxidative stress accelerates the progression of these diseases. To date, the role of the let-7 miRNA family in modulation of heme oxygenase 1 (HMOX1), a key cytoprotective enzyme, remains unknown. Our aims were to determine whether let-7 miRNA directly regulates Bach1, a transcriptional repressor of the HMOX1 gene, and whether indirect up-regulation of HMOX1 by let-7 miRNA attenuates oxidant injury in human hepatocytes. The effects of let-7 miRNA on Bach1 and HMOX1 gene expression in Huh-7 and HepG2 cells were determined by real-time qRT-PCR, Western blot, and luciferase reporter assays. Dual luciferase reporter assays revealed that let-7b, let-7c, or miR-98 significantly decreased Bach1 3'-untranslated region (3'-UTR)-dependent luciferase activity but not mutant Bach1 3'-UTR-dependent luciferase activity, whereas mutant let-7 miRNA containing base complementarity with mutant Bach1 3'-UTR restored its effect on mutant reporter activity. let-7b, let-7c, or miR-98 down-regulated Bach1 protein levels by 50-70%, and subsequently up-regulated HMOX1 gene expression by 3-4 fold, compared with non-specific controls. Furthermore, Huh-7 cells transfected with let-7b, let-7c or miR-98 mimic showed increased resistance against oxidant injury induced by tert-butyl-hydroperoxide (tBuOOH), whereas the protection was abrogated by over-expression of Bach1. In conclusion, let-7 miRNA directly acts on the 3'-UTR of Bach1 and negatively regulates expression of this protein, and thereby up-regulates HMOX1 gene expression. Over-expression of the let-7 miRNA family members may represent a novel approach to protecting human hepatocytes from oxidant injury. BTB and CNC homology 1 (Bach1) is a transcriptional repressor of antioxidative enzymes, such as heme oxygenase-1 (HO-1). Oxidative stress is reportedly involved in insulin secretion impairment and obesity-associated insulin resistance. However, the role of Bach1 in the development of diabetes is unclear. HO-1 expression in the liver, white adipose tissue, and pancreatic islets was markedly upregulated in Bach1-deficient mice. Unexpectedly, glucose and insulin tolerance tests showed no differences in obese wild-type (WT) and obese Bach1-deficient mice after high-fat diet loading for 6 wk, suggesting minimal roles of Bach1 in the development of insulin resistance. In contrast, Bach1 deficiency significantly suppressed alloxan-induced pancreatic insulin content reduction and the resultant glucose elevation. Furthermore, TUNEL-positive cells in pancreatic islets of Bach1-deficient mice were markedly decreased, by 60%, compared with those in WT mice. HO-1 expression in islets was significantly upregulated in alloxan-injected Bach1-deficient mice, whereas expression of other antioxidative enzymes, e.g., catalase, superoxide dismutase, and glutathione peroxidase, was not changed by either alloxan administration or Bach1 deficiency. Our results suggest that Bach1 deficiency protects pancreatic β-cells from oxidative stress-induced apoptosis and that the enhancement of HO-1 expression plays an important role in this protection. Bach1 is a transcriptional repressor of the heme oxygenase (HO)-1 gene. Bach1-null (Bach1(-/-)) mice are reported to be protected from myocardial ischemia/reperfusion injury; however, the effect of Bach1 disruption on another oxidative stress model of hyperoxic lung injury has yet to be determined. To investigate the role of Bach1 in hyperoxic lung injury, Bach1(-/-) mice and wild-type (WT) mice were exposed to 90% O(2). During hyperoxic exposure, the survival of Bach1(-/-) mice was significantly longer than that of WT mice. However, the administration of zinc protoporphyrin, an inhibitor of HO-1 activity, did not change the mortality in either of the mice, thus suggesting that this protective effect was not mediated by an HO-1 overexpression in Bach1(-/-) mice. The indices of lung injury in the lungs of Bach1(-/-) mice were lower than those of WT mice; unexpectedly, however, the levels of IL-6 in bronchoalveolar lavage (BAL) fluid from Bach1(-/-) mice were significantly higher than those of WT mice. Interestingly, the intrapulmonary administration of small interfering RNA against IL-6 was shown to reduce the IL-6 levels in BAL fluids and shorten the survival in Bach1(-/-) mice during hyperoxic exposure. In addition, a chromatin immunoprecipitation analysis revealed the binding of Bach1 to the IL-6 promoter and its detachment after oxidative stress. Considering the previous observation that the transgenic mice overexpressing IL-6 are protected from hyperoxic lung injury, these results therefore indicate that IL-6 mediates an increased survival in Bach1(-/-) mice during hyperoxic exposure. Reactive oxygen species (ROS), by-products of aerobic respiration, promote genetic instability and contribute to the malignant transformation of cells. Among the genes related to ROS metabolism, Bach1 is a repressor of the oxidative stress response, and a negative regulator of ROS-induced cellular senescence directed by p53 in higher eukaryotes. While ROS are intimately involved in carcinogenesis, it is not clear whether Bach1 is involved in this process. We found that senescent Bach1-deficient mouse embryonic fibroblasts (MEFs) underwent spontaneous immortalization the same as did the wild-type cells. When transduced with constitutively active Ras (H-Ras(V12)), the proliferation and colony formation of these cells in vitro were markedly reduced. When transplanted into athymic nude mice, the growth and vascularization of tumors derived from Bach1-deficient cells were also decreased. Gene expression profiling of the MEFs revealed a new H-Ras(V12) signature, which was distinct from the previously reported signatures in epithelial tumors, and was partly dependent on Bach1. The Bach1-deficient cells showed diminished phosphorylation of MEK and ERK1/2 in response to H-Ras(V12), which was consistent with the alterations in the gene expression profile, including phosphatase genes. Finally, Bach1-deficient mice were less susceptible to 4-nitroquinoline-1-oxidide (4-NQO)-induced tongue carcinoma than wild-type mice. Our data provide evidence for a critical role of Bach1 in cell transformation and tumor growth induced by activated H-Ras(V12). Ferritin gene transcription is regulated by heme as is ferritin mRNA translation, which is mediated by the well studied mRNA.IRE/IRP protein complex. The heme-sensitive DNA sequence in ferritin genes is the maf recognition/antioxidant response element present in several other genes that are induced by heme and repressed by Bach1. We now report that chromatin immunoprecipitated with Bach1 antiserum contains ferritin DNA sequences. In addition, overexpression of Bach1 protein in the transfected cells decreased ferritin expression, indicating insufficient endogenous Bach1 for full repression; decreasing Bach1 with antisense RNA increased ferritin expression. Thioredoxin reductase1, a gene that also contains a maf recognition/antioxidant response element but is less studied, responded similarly to ferritin, as did the positive controls heme oxygenase1 and NADP(H) quinone (oxido) reductase1. Bach1-DNA promoter interactions in cells were confirmed in vitro with soluble, recombinant Bach1 protein and revealed a quantitative range of Bach1/DNA stabilities: ferritin L approximately ferritin H approximately beta-globin, beta-globin approximately 2-fold >heme oxygenase1 = quinone reductase beta-globin approximately 4-fold >thioredoxin reductase1. Such results indicate the possibility that modulation of cellular Bach1 concentrations will have variable effects among the genes coordinately regulated by maf recognition/antioxidant response elements in iron/oxygen/antioxidant metabolism. Intracellular heme is a redox active molecule that can be detrimental to cells at high concentrations or under oxidizing conditions. To prevent accumulation, the inducible enzyme heme oxygenase-1 (HMOX1) catalyzes degradation of heme. In the absence of elevated intracellular heme or oxidative stress, the basic region leucine zipper transcriptional regulator BACH1 binds HMOX1 antioxidant response elements and represses transcription. Conversely, increased intracellular heme or sulfhydryl oxidation inactivate BACH1, permitting transcriptional induction of HMOX1. Here, we investigate the effect of BACH1 inactivation on the induction of HMOX1 and as a mechanism for broader gene induction. We show that BACH1 is inactivated at low micromolar arsenite concentrations and that BACH1 inactivation is necessary and sufficient for transcriptional induction of HMOX1. Because BACH1 is thought to interact with antioxidant response element motifs, we further examined the role of BACH1 as a regulator of inducible antioxidant gene expression by assessing the global profile of gene expression following BACH1 knockdown using small interfering RNA. The loss of BACH1 function in human keratinocytes results almost exclusively in HMOX1 induction, suggesting that BACH1 may function as a rheostat regulating levels of intracellular free heme. |
394 | Is Kanzaki disease associated with deficiency in alpha-N-acetylgalactosaminidase? | Yes, Kanzaki disease is attributable to a deficiency in alpha-N-acetylgalactosaminidase, which hydrolyzes GalNAcalpha1-O-Ser/Thr. | [14685826, 15619430, 19683538, 15136691, 11251574, 8577046] | 501 | Alpha-N-acetylgalactosaminidase (alpha-NAGA) deficiency (Schindler/Kanzaki disease) is a clinically and pathologically heterogeneous genetic disease with a wide spectrum including an early onset neuroaxonal dystrophy (Schindler disease) and late onset angiokeratoma corporis diffusum (Kanzaki disease). In alpha-NAGA deficiency, there are discrepancies between the genotype and phenotype, and also between urinary excretion products (sialyl glycoconjugates) and a theoretical accumulated material (Tn-antigen; Gal NAcalpha1-O-Ser/Thr) resulting from a defect in alpha-NAGA. As for the former issue, previously reported genetic, biochemical and pathological data raise the question whether or not E325K mutation found in Schindler disease patients really leads to the severe phenotype of alpha-NAGA deficiency. The latter issue leads to the question of whether alpha-NAGA deficiency is associated with the basic pathogenesis of this disease. To clarify the pathogenesis of this disease, we performed structural and immunocytochemical studies. The structure of human alpha-NAGA deduced on homology modeling is composed of two domains, domain I, including the active site, and domain II. R329W/Q, identified in patients with Kanzaki disease have been deduced to cause drastic changes at the interface between domains I and II. The structural change caused by E325K found in patients with Schindler disease is localized on the N-terminal side of the tenth beta-strand in domain II and is smaller than those caused by R329W/Q. Immunocytochemical analysis revealed that the main lysosomal accumulated material in cultured fibroblasts from patients with Kanzaki disease is Tn-antigen. These data suggest that a prototype of alpha-NAGA deficiency in Kanzaki disease and factors other than the defect of alpha-NAGA may contribute to severe neurological disorders, and Kanzaki disease is thought to be caused by a single enzyme deficiency. BACKGROUND: Kanzaki disease (OMIM#104170) is attributable to a deficiency in alpha-N-acetylgalactosaminidase (alpha-NAGA; E.C.3.2.1.49), which hydrolyzes GalNAcalpha1-O-Ser/Thr. Missense mutations, R329W or R329Q were identified in two Japanese Kanzaki patients. Although they are on the same codon, the clinical manifestation was more severe in R329W because an amino acid substitution led to protein instability resulting in structural change, which is greater in R329W than in R329Q. OBJECTIVE: To examine whether the different clinical phenotypes are attributable to the two mutations. METHODS: Plasma alpha-NAGA activity and urinary excreted glycopeptides were measured and three-dimensional models of human alpha-NAGA and its complexes with GalNAcalpha1-O-Ser and GalNAcalpha1-O-Thr were constructed by homology modeling. RESULTS: Residual enzyme activity was significantly higher in the R329Q- than the R329W mutant (0.022+/-0.005 versus 0.005+/-0.001 nmol/h/ml: p<0.05); the urinary ratios of GalNAcalpha1-O-Ser:GalNAcalpha1-O-Thr were 2:10 and 8:10, respectively. GalNAcalpha1-O-Ser/Thr fit tightly in a narrow space of the active site pocket of alpha-NAGA. GalNAcalpha1-O-Thr requires a larger space to associate with alpha-NAGA because of the side chain (CH3) of the threonine residue. CONCLUSION: Our findings suggest that the association of alpha-NAGA with its substrates is strongly affected by the amino acid substitution at R329 and that the association with GalNAcalpha1-O-Thr is more highly susceptible to structural changes. The residual mutant enzyme in R329W could not associate with GalNAcalpha1-O-Thr and GalNAcalpha1-O-Ser. However, the residual mutant enzyme in R329Q catalyzed GalNAcalpha1-O-Ser to some extent. Therefore, the urinary ratio of GalNAcalpha1-O-Ser:GalNAcalpha1-O-Thr was lower and the clinical phenotype was milder in the R329Q mutation. Structural analysis revealed biochemical and phenotypic differences in these Kanzaki patients with the R329Q and R329W mutation. alpha-N-acetylgalactosaminidase (alpha-NAGAL; E.C. 3.2.1.49) is a lysosomal exoglycosidase that cleaves terminal alpha-N-acetylgalactosamine residues from glycopeptides and glycolipids. In humans, a deficiency of alpha-NAGAL activity results in the lysosomal storage disorders Schindler disease and Kanzaki disease. To better understand the molecular defects in the diseases, we determined the crystal structure of human alpha-NAGAL after expressing wild-type and glycosylation-deficient glycoproteins in recombinant insect cell expression systems. We measured the enzymatic parameters of our purified wild-type and mutant enzymes, establishing their enzymatic equivalence. To investigate the binding specificity and catalytic mechanism of the human alpha-NAGAL enzyme, we determined three crystallographic complexes with different catalytic products bound in the active site of the enzyme. To better understand how individual defects in the alpha-NAGAL glycoprotein lead to Schindler disease, we analyzed the effect of disease-causing mutations on the three-dimensional structure. We describe the neurologic findings in a patient with alpha-N-acetylgalactosaminidase deficiency (Kanzaki disease). Clinical and electrophysiologic studies revealed sensory-motor polyneuropathy, and sural nerve pathology showed decreased density of myelinated fibers with axonal degeneration. The patient had mildly impaired intellectual function with abnormal brain MRI and sensory-neuronal hearing impairment with repeated episodes of vertigo attacks. These findings suggest that Kanzaki disease may develop neurologic complications in the CNS and peripheral nervous system. Schindler disease and Kanzaki disease are caused by a deficient lysosomal enzyme, alpha-N-acetylgalactosaminidase (E.C.3.2.1.49). Two German children were first reported in 1987 and other two Dutch children were recently reported in 1993. These children were very similar clinically and characterized by maked neuroaxonal dystrophy of an infantile onset. This disease (type 1) was named Schindler disease. On the other hand, an adult patient with profuse angiokeratoma corporis diffusum but minimum involvement in nervous system was reported in 1987 from Japan. This disease (type 2) was named Kanzaki disease (Mckusick catalog No. 104170). Molecular analyses of these diseases revealed one each point mutation in the encoding gene. Clinical, ultrastructural and molecular studies of these disease were described. |
395 | Is Mycobacterium avium less susceptible to antibiotics than Mycobacterium tuberculosis? | Mycobacterium avium causes disseminated infection in patients with acquired immune deficiency syndrome. M tuberculosis disease is preventable and curable and yet communicable, physicians should maintain a high degree of suspicion for tuberculosis in HIV-infected adults. In comparison, the goal of treating M avium complex in patients with advanced HIV disease is to reduce constitutional symptoms and improve survival. Patients who were suspected to have disseminated mycobacterial infection, presenting fever and (preferably) a CD4 T cell count<100.0 cell/mL were investigated. Twelve (15%) of the 80 blood cultures were positive for mycobacteria, with Mycobacterium avium being identified in 7 (8.8%) samples and M. tuberculosis in 5 (6.2%). The antimycobacterial activities of RS-112997, RS-124922 and RS-118641, three capuramycin analogues that inhibit phospho-N-acetylmuramyl-pentapeptide translocase, were tested against clinical isolates of Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium intracellulare. The MIC50/90 (mg/L) results for RS-118641 were: M. tuberculosis, 1/2; multidrug-resistant (MDR) M. tuberculosis, 0.5/2; M. avium, 4/8; and M. intracellulare, 0.06/0.5 | [17548640, 10988097, 19956964, 19302308, 17897062, 12355367, 19119013, 21258569, 15328105, 15347635, 1441463, 16410940] | 502 | Few studies have compared the clinical and radiographic findings of tuberculomas to those of solitary pulmonary nodules (SPNs) caused by Mycobacterium avium complex (MAC). We retrospectively analyzed clinical and radiographic findings from 26 patients with tuberculomas and 15 patients with SPNs caused by MAC. Median SPN size was 22 mm. In 26 patients (63%), the SPN was detected during a routine health checkup or evaluation of organs other than lungs. Patients with SPNs due to MAC were slightly older (median = 59 years) compared with those with tuberculomas (median = 50 years; P = 0.044). When we compared computed tomography (CT) features between patients with tuberculomas and patients with MAC, no significant differences were found in SPN location or the presence of calcification, cavitation, central low attenuation, and the satellite lesions. Although the maximum standardized uptake values were slightly higher in patients with SPNs due to MAC (median = 8.5) compared with those with tuberculomas (median = 2.2), this difference was not significant (P = 0.053). Of the 15 patients with SPNs due to MAC, 10 were initially diagnosed with "tuberculoma" and administered antituberculosis medication. MAC pulmonary disease should be considered in the differential diagnosis of SPNs, even when encountered in geographic regions with a high prevalence of pulmonary tuberculosis. AIMS: Polymerase chain reaction (PCR) is the most rapid and sensitive method for diagnosing mycobacterial infections and identifying the aetiological Mycobacterial species in order to administer the appropriate therapy and for better patient management. METHODS AND RESULTS: Two hundred and thirty-five samples from 145 clinically suspected cases of tuberculosis were processed for the detection of Mycobacterial infections by ZN (Ziehl Neelsen) smear examination, L-J & BACTEC MGIT-960 culture and multiplex PCR tests. The multiplex PCR comprised of genus-specific primers targeting hsp65 gene, Mycobacterium tuberculosis complex-specific primer targeting cfp10 (Rv3875, esxB) region and Mycobacterium avium complex-specific primer pairs targeting 16S-23S Internal Transcribed Spacer sequences. The multiplex PCR developed had an analytical sensitivity of 10 fg (3-4 cells) of mycobacterial DNA. The multiplex PCR test showed the highest (77.24%) detection rate, while ZN smear examination had the lowest (20%) detection rate, which was bettered by L-J culture (34.4%) and BACTEC MGIT-960 culture (50.34%) methods. The mean isolation time for M. tuberculosis was 19.03 days in L-J culture and 8.7 days in BACTEC MGIT-960 culture. Using the multiplex PCR, we could establish M. tuberculosis + M. avium co-infection in 1.3% HIV-negative and 2.9% HIV-positive patients. The multiplex PCR was also highly useful in diagnosing mycobacteraemia in 38.09% HIV-positive and 15.38% HIV-negative cases. CONCLUSIONS: The developed in-house multiplex PCR could identify and differentiate the M. tuberculosis and M. avium complexes from other Mycobacterial species directly from clinical specimens. SIGNIFICANCE AND IMPACT OF THE STUDY: The triplex PCR developed by us could be used to detect and differentiate M. tuberculosis, M. avium and other mycobacteria in a single reaction tube. Pulmonary tuberculosis (TB) has again become a global problem: it infects 2.2 billion people world-wide, caused the deaths of over 3 million last year and will produce over 8 million new cases of TB this coming year. Although effective therapy is widely available for antibiotic susceptible strains of Mycobacterium tuberculosis, current drugs are relatively useless against multi-drug resistant infections (MDRTB). Mortality is almost complete within two years regardless of therapy, and in the case of co-infection with HIV/AIDS, mortality is 100% within a few months of diagnosis especially the M. tuberculosis strain in XDRTB. As of the time of this writing no new effective anti-TB drugs have been made available by the pharmaceutical industry and XDRTB. Because TB is an intracellular infection of the non-killing macrophage of the lung, any agent that is to prove effective must have activity against MDRTB and XDRTB strains that have been phagocytosed by the human macrophage. This review intents to provide cogent in vitro, ex vivo and in vivo evidence that supports the use of a variety of commonly available phenothiazines for the therapy of MDRTB and XDRTB, especially when the prognosis of the infection is poor and the use of the recommend agents can take place along lines of "compassionate therapy". In addition, we will describe the macrophage assay as indispensable when an agent is to be further studied for its effectiveness as an anti-TB drug. In vitro studies if not complemented by ex vivo studies will for the most part be dead-ended since few agents that have activity in vitro have any activity against phagocytosed M. tuberculosis. Mycobacterium avium causes disseminated infection in patients with acquired immune deficiency syndrome. Mycobacterium tuberculosis is a pathogen associated with the deaths of millions of people worldwide annually. Effective therapeutic regimens exist that are limited by the emergence of drug resistance and the inability of antibiotics to kill dormant organisms. The present study describes a system using Mycobacterium smegmatis, an avirulent mycobacterium, to deliver the lytic phage TM4 where both M. avium and M. tuberculosis reside within macrophages. These results showed that treatment of M. avium-infected, as well as M. tuberculosis-infected, RAW 264.7 macrophages, with M. smegmatis transiently infected with TM4, resulted in a significant time- and titer-dependent reduction in the number of viable intracellular bacilli. In addition, the M. smegmatis vacuole harboring TM4 fuses with the M. avium vacuole in macrophages. These results suggest a potentially novel concept to kill intracellular pathogenic bacteria and warrant future development. INTRODUCTION: The purpose of this study was to separate MAC lung disease from colonization and to define indications for treatment. MATERIALS AND METHODOLOGY: Over 4 years, we evaluated patients who had positive MAC cultures, MAC infection and coinfection with MTB. In the first study, 42 immunocompetent patients with sputum or BAL culture positive only for MAC during a single year (2004) were reviewed. On clinical and radiographic review, they were classified as disease related to MAC, likely related to MAC or unrelated to MAC. In the second study, we reviewed all immunocompetent patients, during two years (2004-2005), whose respiratory secretions cultured both MTB and nontuberculous mycobacteria (NTM). In the last study, we evaluated pulmonary function (PF) in patients with MAC infection before and after therapy (2006- 2007). PF was evaluated in patients following ATS guidelines. RESULTS: Lung disease was related/likely related to MAC in 21 patients (50%) and not related in 21 (50%). In patients with MAC-related lung disease, the primary physician did not consider the diagnosis except when that physician was a pulmonologist. Half of those with MAC-related lung disease were smokers, white and US-born. There were 12 immunocompetent patients with MTB and NTM cultures. Eleven were non-white and all were foreign-born. Presentation and clinical course were consistent with MTB. All 8 patients with abnormal PF improved. CONCLUSIONS: The prevalence of MAC lung infection in two inner city hospitals was four times higher than that of TB. The indication for treatment of MAC infection should also rely heavily on clinical and radiological evidence when there is only one positive sputum culture. The diagnosis was considered only when the admitting physician was a pulmonologist. Most patients with combined infection were clinically consistent with MTB and responded to anti MTB treatment alone. Treatment with anti-MAC therapy improved PF in those patients whose PF was abnormal to begin with. OBJECTIVES: The antimycobacterial activities of RS-112997, RS-124922 and RS-118641, three capuramycin analogues that inhibit phospho-N-acetylmuramyl-pentapeptide translocase, were tested against clinical isolates of Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium intracellulare. METHODS AND RESULTS: MICs were determined by the broth microdilution method using a modified Middlebrook 7H9 broth. RS-118641 was the most potent compound overall. The MIC50/90 (mg/L) results for RS-118641 were: M. tuberculosis, 1/2; multidrug-resistant (MDR) M. tuberculosis, 0.5/2; M. avium, 4/8; and M. intracellulare, 0.06/0.5. No statistically significant differences in MIC distributions were observed between non-MDR and MDR M. tuberculosis for any of the capuramycin analogues tested. In order to evaluate the therapeutic efficacy of RS-112997 and RS-124922 in a murine lung model of tuberculosis, both compounds were administered intranasally at 0.1 or 1 mg/mouse/day for 12 days. The mycobacterial load in the lungs was significantly lower in all treatment groups than in the untreated controls. Additional experiments were performed to evaluate the therapeutic efficacy of the three compounds against the M. intracellulare infection in mice. All compounds were administered intranasally at 0.1 mg/mouse/day for 21 days. The mycobacterial load in the lungs was significantly lower in all treatment groups than in the untreated controls. CONCLUSIONS: These results suggest that capuramycin analogues exhibit strong antimycobacterial potential and should be considered for further evaluation in the treatment of M. tuberculosis and M. avium-M. intracellulare complex infections in humans. The use of highly active antiretroviral therapy (HAART) for the treatment of HIV infection has been associated with a marked reduction in the incidence of most opportunistic infections. From April 2001 to February 2002, 80 blood samples from patients who were suspected to have disseminated mycobacterial infection, presenting fever and (preferably) a CD4 T cell count < 100.0 cell/mL were investigated. Twelve (15%) of the 80 blood cultures were positive for mycobacteria, with Mycobacterium avium being identified in 7 (8.8%) samples and M. tuberculosis in 5 (6.2%). The TCD4+ count at the time of M. avium bacteremia ranged from 7 cells/microL (average of 48.5 cell/microL), while in M. tuberculosis bacteremia it ranged from 50.0 cells/microL (average of 80.0 cell/microL). The prevalence of M. avium bacteremia in our study follows the expected decline in opportunistic infections observed after the introduction of HAART; however, mycobacteremia by M. tuberculosis still indicates a high prevalence of tuberculosis infection in AIDS patients. |
396 | What molecule is targeted by suvorexant? | Suvorexant is a dual orexin receptor antagonist for the treatment of sleep onset and sleep maintenance insomnia. | [25406050, 25533960, 22920041, 21473737, 25397996, 24757363, 26478806, 23197752, 25489915, 25667197] | 503 | Insomnia is a highly prevalent disorder that can occur in conjunction with other medical or psychiatric conditions or can occur in the absence of a coexisting disorder. Regardless, treatment of insomnia is beneficial to the patient and may benefit comorbidities if they exist. Nonpharmacologic modalities such as sleep hygiene and stimulus controls are important mainstays of insomnia therapy, but may not be sufficient to treat the disorder. Dual orexin receptor antagonists (DORAs) are a new class of insomnia medication that target wakefulness-promoting neuropeptides to regulate the sleep-wake cycle. Suvorexant is the first DORA to be approved and has demonstrated efficacy at decreasing both time to sleep onset and increasing total sleep time compared with placebo. Suvorexant has a novel mechanism of action and may represent an alternative for patients who cannot tolerate or do not receive benefit from traditional sleep agents. Suvorexant is generally effective and well tolerated, but has not been compared head to head with traditional sleep agents and being only newly available, lacks a longer-term 'real-world' experience base. The orexin-1 and orexin-2 receptors are two G protein-coupled receptors that bind the neuropeptides orexin-A and orexin-B. Dual antagonism of the receptors by small molecules is clinically efficacious in the treatment of insomnia, where the most advanced molecule suvorexant has recently been approved. The scope of this article is to review the small molecule orexin receptor antagonist patent literature between January 2012 and January 2014. |
397 | For which type of diabetes can empagliflozin be used? | The oral antidiabetes agent, empagliflozin, can be used as monotherapy or alongside other glucose-lowering treatments, including insulin, to treat T2DM. | [23398530, 24944269, 25775379, 24943000, 24948511, 24007456, 24622369, 26557225, 25692841, 25274537, 23940010, 25712444, 25941565, 25644093, 24746173, 25301180, 22268612, 24843716, 23906374, 25332189, 24463454, 25598831, 24795251, 24964723, 24991224, 24186878] | 504 | AIM: This Phase IIb, randomized, double-blind, placebo-controlled trial evaluated the efficacy, safety, tolerability and pharmacokinetics of empagliflozin in patients with type 2 diabetes. METHODS: Four hundred and eight patients (treatment-naïve or after a 4-week wash-out period) were randomized to receive empagliflozin 5, 10 or 25 mg once daily, placebo or open-label metformin for 12 weeks. The primary endpoint was change in haemoglobin A1c (HbA1c) after 12 weeks. RESULTS: After 12 weeks' treatment, empagliflozin showed dose-dependent reductions in HbA1c from baseline [5 mg: -0.4%, 10 mg: -0.5%, 25 mg: -0.6%; all doses p < 0.0001 vs. placebo (+0.09%)]. Fasting plasma glucose (FPG) decreased with empagliflozin [5 mg: -1.29 mmol/l, 10 mg: -1.61 mmol/l, 25 mg: -1.72 mmol/l; all doses p < 0.0001 vs. placebo (+0.04 mmol/l)]. Body weight decreased in all empagliflozin groups (all doses p < 0.001 vs. placebo). The incidence of adverse events (AEs) was similar in the placebo (32.9%) and empagliflozin (29.1%) groups. The most frequently reported AEs on empagliflozin were pollakiuria (3.3% vs. 0% for placebo), thirst (3.3% vs. 0% for placebo) and nasopharyngitis (2.0% vs. 1.2% for placebo). AEs consistent with urinary tract infections (UTIs) were reported in four (1.6%) patients on empagliflozin vs. one (1.2%) on placebo. Genital infections were reported in five (2%) patients on empagliflozin vs. 0% on placebo. No UTIs or genital infections led to premature discontinuation. CONCLUSIONS: In patients with type 2 diabetes, empagliflozin resulted in dose-dependent, clinically meaningful reductions in HbA1c and FPG, and reductions in body weight compared with placebo. Empagliflozin was well-tolerated with a favourable safety profile. Diabetic nephropathy is the leading cause of end-stage renal disease in humans in the Western world. The recent development of Na+-glucose cotransporter 2 (SGLT2) inhibitors offers a new antidiabetic therapy via enhanced glucose excretion. Whether this strategy exerts beneficial effects on the development of type 2 diabetic nephropathy is still largely unclear. We investigated the effects of the specific SGLT2 inhibitor empagliflozin in BTBR.Cg-Lep<ob>/WiscJ (BTBR ob/ob) mice, which spontaneously develop type 2 diabetic nephropathy. In the first experiment, BTBR ob/ob mice received either a diet containing 300 ppm empagliflozin or equicaloric placebo chow for 12 wk. In the second experiment, BTBR ob/ob mice received 1 μg·kg body wt(-1)·day(-1) ANG II to induce arterial hypertension and were separated into the same two diet groups for 6 wk. In both experiments, empagliflozin treatment enhanced glucosuria, thereby lowering blood glucose. Independently of hypertension, empagliflozin reduced albuminuria in diabetic mice. However, empagliflozin treatment affected diabetes-related glomerular hypertrophy, markers of renal inflammation, and mesangial matrix expansion only in BTBR ob/ob mice without hypertension. In summary, empagliflozin demonstrated significant antihyperglycemic effects, differentially ameliorating early features of diabetic nephropathy in BTBR ob/ob mice with and without hypertension. BACKGROUND: Treatment of type 2 diabetes mellitus invariably requires the use of multiple daily medications which can impact negatively on patient adherence. As a result, there is growing interest in the use of single-pill combinations that can reduce the pill burden. Many such formulations incorporate metformin, although this agent is not suitable for all patients. The single-pill combination of the dipeptidyl peptidase-4 inhibitor linagliptin with the sodium glucose co-transporter 2 inhibitor empagliflozin offers a new and attractive option, given their complementary mechanisms of action. SCOPE: Publications with titles containing the keywords 'linagliptin' or 'empagliflozin' were identified from a non-systematic search of PubMed without date restrictions, together with abstracts presented at the annual meetings of the American Diabetes Association and the European Association for the Study of Diabetes 2012-2014. ClinicalTrials.gov was searched for entries containing these two keywords. Additional references known to the author were included. FINDINGS: The efficacy and safety of linagliptin and empagliflozin as monotherapy or in combination with other oral antidiabetic drugs has been established through extensive clinical trial programs. Studies specifically evaluating the efficacy/safety of a dipeptidyl peptidase-4 inhibitor/sodium glucose co-transporter 2 inhibitor in combination are limited, but do include two studies of linagliptin/empagliflozin of up to 52 weeks in duration. These studies show that the single-pill combination of linagliptin and empagliflozin produced clinical improvements in glycemic control that were generally superior to the improvements seen with linagliptin and empagliflozin alone, but with a safety profile comparable to that of the individual constituents. CONCLUSIONS: The single-pill combination of linagliptin and empagliflozin, with their complementary mechanisms of action, is a promising treatment option for patients with type 2 diabetes mellitus. It would reduce the daily pill burden in this population, potentially improving adherence to, and optimizing the benefits of, treatment of diabetes mellitus. BACKGROUND: Evidence concerning the importance of glucose lowering in the prevention of cardiovascular (CV) outcomes remains controversial. Given the multi-faceted pathogenesis of atherosclerosis in diabetes, it is likely that any intervention to mitigate this risk must address CV risk factors beyond glycemia alone. The SGLT-2 inhibitor empagliflozin improves glucose control, body weight and blood pressure when used as monotherapy or add-on to other antihyperglycemic agents in patients with type 2 diabetes. The aim of the ongoing EMPA-REG OUTCOME™ trial is to determine the long-term CV safety of empagliflozin, as well as investigating potential benefits on macro-/microvascular outcomes. METHODS: Patients who were drug-naïve (HbA1c ≥7.0% and ≤9.0%), or on background glucose-lowering therapy (HbA1c ≥7.0% and ≤10.0%), and were at high risk of CV events, were randomized (1:1:1) and treated with empagliflozin 10 mg, empagliflozin 25 mg, or placebo (double blind, double dummy) superimposed upon the standard of care. The primary outcome is time to first occurrence of CV death, non-fatal myocardial infarction, or non-fatal stroke. CV events will be prospectively adjudicated by an independent Clinical Events Committee. The trial will continue until ≥691 confirmed primary outcome events have occurred, providing a power of 90% to yield an upper limit of the adjusted 95% CI for a hazard ratio of <1.3 with a one-sided α of 0.025, assuming equal risks between placebo and empagliflozin (both doses pooled). Hierarchical testing for superiority will follow for the primary outcome and key secondary outcomes (time to first occurrence of CV death, non-fatal myocardial infarction, non-fatal stroke or hospitalization for unstable angina pectoris) where non-inferiority is achieved. RESULTS: Between Sept 2010 and April 2013, 592 clinical sites randomized and treated 7034 patients (41% from Europe, 20% from North America, and 19% from Asia). At baseline, the mean age was 63 ± 9 years, BMI 30.6 ± 5.3 kg/m2, HbA1c 8.1 ± 0.8%, and eGFR 74 ± 21 ml/min/1.73 m2. The study is expected to report in 2015. DISCUSSION: EMPA-REG OUTCOME™ will determine the CV safety of empagliflozin in a cohort of patients with type 2 diabetes and high CV risk, with the potential to show cardioprotection. TRIAL REGISTRATION: Clinicaltrials.gov NCT01131676. BACKGROUND: Metformin is the recommended first-line pharmacotherapy for patients with type 2 diabetes. There is no consensus on the optimum second-line pharmacotherapy. We compared the efficacy and safety of the sodium glucose cotransporter 2 inhibitor empagliflozin and the sulfonylurea glimepiride as add-on to metformin in patients with type 2 diabetes. METHODS: In this double-blind phase 3 trial, patients (aged ≥18 years) with type 2 diabetes and HbA1c concentrations of 7-10%, despite metformin treatment and diet and exercise counselling, were randomly assigned in a 1:1 ratio with a computer-generated random sequence, stratified by HbA1c, estimated glomerular filtration rate (eGFR), and region, to empagliflozin (25 mg once daily, orally) or glimepiride (1-4 mg once daily, orally) as add-on to metformin for 104 weeks. Patients and investigators were masked to treatment assignment. The primary endpoint was change from baseline in HbA1c levels at weeks 52 and 104. Differences in the primary endpoint were first tested for non-inferiority (based on a margin of 0·3%). If non-inferiority was shown, differences in the primary endpoint at week 104 were then tested for superiority. Analysis was done on the full-analysis set-ie, patients who were treated with at least one dose of study drug and had a baseline HbA1c value. This study is registered with ClinicalTrials.gov, number NCT01167881. A 104-week extension is ongoing. FINDINGS: Between August, 2010, and June, 2011, 1549 patients were randomly assigned to receive empagliflozin (n=769) or glimepiride (n=780); four patients in the empagliflozin group did not receive the assigned treatment. Empagliflozin was non-inferior to glimepiride at both timepoints. At week 104, adjusted mean difference in change from baseline in HbA1c with empagliflozin versus glimepiride was -0·11% (95% CI -0·19 to -0·02; p=0·0153 for superiority). Adverse events were reported in 661 (86%) patients treated with empagliflozin and 673 (86%) patients treated with glimepiride. Severe adverse events were reported in 72 (9%) patients in the empagliflozin group and 68 (9%) in the glimepiride group. Serious adverse events were reported in 119 (16%) patients in the empagliflozin group and 89 (11%) in the glimepiride group. Confirmed hypoglycaemic adverse events (plasma glucose ≤3·9 mmol/L or requiring assistance) at week 104 were reported in 19 (2%) patients treated with empagliflozin and 189 (24%) patients treated with glimepiride. INTERPRETATION: Empagliflozin might be an effective and a well tolerated second-line treatment option for patients with type 2 diabetes who have not achieved good glycaemic control on metformin. FUNDING: Boehringer Ingelheim and Eli Lilly. BACKGROUND: Sulfonylureas (SUs) are commonly used in the treatment of type 2 diabetes (T2DM), usually as second-line treatment after the failure of metformin. However, SUs are associated with poor durability, hypoglycemia and weight gain. Empagliflozin is a sodium glucose cotransporter 2 (SGLT2) inhibitor in development for the treatment of T2DM. In Phase II/III trials, empagliflozin reduced hyperglycemia, body weight and blood pressure, with a low incidence of hypoglycemia. The aim of this Phase III study is to compare the effects of empagliflozin and the SU glimepiride as second-line therapy in patients with T2DM inadequately controlled with metformin immediate release (IR) and diet/exercise. METHOD: After a 2-week placebo run-in, patients were randomized to receive empagliflozin 25 mg once daily (qd) or glimepiride 1-4 mg qd double-blind for 2 years, in addition to metformin IR. Patients who participate in the initial 2-year randomization period will be eligible for a 2-year double-blind extension. The primary endpoint is change from baseline in HbA1c. Secondary endpoints are change from baseline in body weight, the incidence of confirmed hypoglycemia and changes in systolic and diastolic blood pressure. Exploratory endpoints include markers of insulin secretion, body composition and responder analyses. Safety endpoints include the incidence of adverse events (AEs) (including macro- and microvascular adverse events) and changes from baseline in clinical laboratory parameters. RESULTS: Between August 2010 and June 2011, 1549 patients were randomized and 1545 patients were treated. At baseline, mean (SD) age was 55.9 (10.4) years, HbA1c was 7.92 (0.84)%, body mass index was 30.11 (5.59) kg/m², systolic blood pressure was 133.5 (15.9) mmHg and diastolic blood pressure was 79.5 (9.4) mmHg. DISCUSSION: This is the largest study to compare the efficacy and safety of an SGLT2 inhibitor with an SU in patients with T2DM inadequately controlled on metformin to date. In addition to determining the effects of these treatments on glycemic control over the long term, this study will investigate effects on beta-cell function, cardiovascular risk factors and markers of renal function/damage. The results will help to inform the choice of second-line treatment in patients with T2DM who have failed on metformin. TRIAL REGISTRATION: Clinicaltrials.gov NCT01167881. BACKGROUND: The sodium-glucose cotransporter 2 (SGLT2) inhibitors, which include canagliflozin, dapagliflozin, and empagliflozin, represent a new class of antihyperglycemic agents. Few studies have assessed their cost per response, with "cost per response" being the total cost of a select drug, divided by the resulting change in glycated hemoglobin (HbA1c) levels. OBJECTIVE: To examine the drug cost of SGLT2 inhibitors per a reduction in placebo-adjusted 1% HbA1c in patients with type 2 diabetes mellitus who received treatment during 26 weeks with canagliflozin, dapagliflozin, or empagliflozin. METHODS: The drug cost per response for each of the 3 agents individually was assessed based on data from a subset of clinical trials discussed in the prescribing information for each drug that were all placebo-controlled studies evaluating each drug as monotherapy, dual therapy (combined with metformin), and triple therapy (combined with metformin and a sulfonylurea) in patients with uncontrolled, type 2 diabetes mellitus. The US 2015 wholesale acquisition cost for each drug was used to calculate each drug's treatment costs over 26 weeks. The average cost per response for each drug was defined as the prescription drug cost of each SGLT2 inhibitor, divided by the average, placebo-adjusted HbA1c reduction at 26 weeks. RESULTS: The drug cost per unit dose was the same for canagliflozin (100 mg or 300 mg), dapagliflozin (5 mg or 10 mg), and empagliflozin (10 mg or 25 mg), at $11.43. The drug cost per placebo-adjusted 1% HbA1c reduction varied by agent and by dose, as a result of the differences in the treatment responses for each of the 3 drugs. The costs per response for canagliflozin 100 mg as monotherapy, dual therapy, and triple therapy regimens ranged from $2286 to $3355, and for canagliflozin 300 mg, from $1793 to $2702. The costs per response for dapagliflozin 5 mg as monotherapy and dual therapy (triple therapy was not available at the time of the study) ranged from $4161 to $5201; the cost for dapagliflozin 10 mg ranged from $2972 to $4161. The costs per response for empagliflozin 10 mg ranged from $2972 to $3467 across the monotherapy, dual therapy, and triple therapy regimens; the cost for empagliflozin 25 mg ranged from $2311 to $3467. CONCLUSION: Simple analyses, such as the drug cost per placebo-adjusted 1% reduction in HbA1c, may be useful when considering the addition of antihyperglycemic agents to the health plan's formulary. The treatment of patients with type 2 diabetes is typically accompanied by hypoglycemia, if insulin or derivatives of sulfonylurea are used within the treatment. Apart from the fact that hypoglycemias are the major obstacle to achieving the desirable compensation of diabetes, hypoglycemia also has a number of serious clinical consequences. A long term serious hypoglycemia may lead to a sudden death, heart attack or irreversible brain damage. Clinically significant are also the light or asymptomatic hypoglycemias which in a considerably negative way affect the patient's quality of life. The use of modern technologies in continuous monitoring of glycemias has shown that the occurrence of asymptomatic hypoglycemias is much higher than we anticipated and that they largely involve nocturnal hypoglycemia. Hypoglycemia is associated with an increased level of depression, anxiety, dissatisfaction with the treatment and with a greater number of physician office visits. Nocturnal hypoglycemia has a negative impact on the quality of sleep, it may impair cognitive functions and performance efficiency next day. The prevention of hypoglycemia is therefore one of the basic goals of diabetes treatment and the low risk of hypoglycemia is among the main requirements that we place on the newly developed antidiabetic drugs. The negligible risk of hypoglycemia, which is comparable to placebo both in monotherapy and in most combinations with the antidiabetic drugs available today, is evidenced by the data from the studies undertaken with empagliflozin. It shows that the low risk of hypoglycemia is one of the benefits of gliflozins, the new group of medications with a unique mechanism of effect which has quite recently appeared on our market. Data from five randomized, placebo-controlled, multiple oral dose studies of empagliflozin in patients with type 2 diabetes mellitus (T2DM; N = 974; 1-100 mg q.d.; ≤12 weeks) were used to develop a population pharmacokinetic (PK) model for empagliflozin. The model consisted of two-compartmental disposition, lagged first-order absorption and first-order elimination, and incorporated appropriate covariates. Population estimates (interindividual variance, CV%) of oral apparent clearance, central and peripheral volumes of distribution, and inter-compartmental clearance were 9.87 L/h (26.9%), 3.02 L, 60.4 L (30.8%), and 5.16 L/h, respectively. An imposed allometric weight effect was the most influential PK covariate effect, with a maximum effect on exposure of ±30%, using 2.5th and 97.5th percentiles of observed weights, relative to the median observed weight. Sex and race did not lend additional description to PK variability beyond allometric weight effects, other than ∼25% greater oral absorption rate constant for Asian patients. Age, total protein, and smoking/alcohol history did not affect PK parameters. Predictive check plots were consistent with observed data, implying an adequate description of empagliflozin PKs following multiple dosing in patients with T2DM. The lack of marked covariate effects, including weight, suggests that no exposure-based dose adjustments were required within the study population and dose range. OBJECTIVE: To review available studies of empagliflozin, a sodium glucose co-transporter-2 (SGLT2) inhibitor approved in 2014 by the European Commission and the United States Food and Drug Administration for the treatment of type 2 diabetes mellitus (T2DM). DATA SOURCES: PubMed was searched using the search terms empagliflozin, BI 10773, and BI10773, for entries between January 1, 2000, and December 1, 2014. Reference lists from retrieved articles were searched manually for additional peer-reviewed publications. STUDY SELECTION AND DATA EXTRACTION: All publications reporting clinical trials of empagliflozin were eligible for inclusion. DATA SYNTHESIS: Empagliflozin is a new once-daily oral SGLT2 inhibitor with a mechanism of action that is independent of β-cell function and the insulin pathway. Data from a comprehensive phase III clinical trial program have demonstrated its efficacy as monotherapy, as add-on to other glucose-lowering agents, and in different patient populations. In these studies, empagliflozin resulted in improvements in blood glucose levels as well as reductions in body weight and blood pressure. Empagliflozin was well tolerated and was not associated with an increased risk of hypoglycemia versus placebo. CONCLUSION: The oral antidiabetes agent, empagliflozin, can be used as monotherapy or alongside other glucose-lowering treatments, including insulin, to treat T2DM. The combination of metformin and a sulfonylurea is commonly used in type 2 diabetes mellitus. Many patients on this combination therapy do not achieve or maintain glycemic targets and require the addition of a third antihyperglycemic agent. Among the options are the sodium glucose cotransporter 2 (SGLT2) inhibitors, a recently developed class of medications that effectively improve glycemic control and are associated with reduction in body weight and blood pressure. This article evaluates a 24-week, randomized, placebo-controlled study of the SGLT2 inhibitor empagliflozin, added to metformin plus sulfonylurea regimens. Empagliflozin led to significant reductions in glycated hemoglobin and fasting plasma glucose, as well as body weight and systolic blood pressure. Adverse events typically recorded with SGLT2 inhibitors were observed; notably, genital infections occurred in more patients on empagliflozin than placebo. Overall, empagliflozin was well tolerated. These results indicate that SGLT2 inhibitors can be successfully added to metformin plus sulfonylurea regimens. SGLT2 inhibitors are not the only therapeutic option in this clinical situation; however, based on the secondary effects observed in this and other studies, they appear to be of particular value for patients who are obese or overweight. INTRODUCTION: Despite the availability of numerous anti-diabetes drugs and treatment guidelines, many patients with type 2 diabetes mellitus (T2DM) do not reach recommended targets for glycemic control. There remains an unmet need for effective and well-tolerated anti-diabetes agents that can be used as monotherapy or in combination with other therapies to improve glycemic control in patients with T2DM. Sodium glucose cotransporter 2 (SGLT2) inhibitors are a new class of treatment for T2DM that reduce hyperglycemia by reducing renal glucose reabsorption and thereby increasing urinary glucose excretion. AREAS COVERED: This paper reviews the pharmacokinetic and pharmacodynamic properties of the SGLT2 inhibitor empagliflozin , the results of clinical trials investigating the efficacy of empagliflozin given as monotherapy or as add-on therapy on glycemic control, body weight, and blood pressure in patients with T2DM, and the safety and tolerability profile of empagliflozin. EXPERT OPINION: Empagliflozin offers good glycemic efficacy, weight loss, blood pressure reduction, and a low risk of hypoglycemia. These attributes, coupled with the ability to be used in virtually any combination with other anti-diabetes agents and at any stage in the disease process, provide a welcome new agent to our armamentarium of drugs to help manage T2DM. INTRODUCTION: To evaluate the pharmacodynamics, pharmacokinetics, safety and tolerability of empagliflozin in Japanese patients with type 2 diabetes mellitus. MATERIALS AND METHODS: In this 4-week, multiple dose, randomized, parallel-group, double-blind, placebo-controlled trial, patients (n = 100) were randomized to receive 1, 5, 10 or 25 mg of empagliflozin, or placebo once daily. Key end-points were urinary glucose excretion (UGE), fasting plasma glucose (FPG) and eight-point glucose profile. RESULTS: Data are presented for 1, 5, 10, 25 mg of empagliflozin and placebo groups, respectively. Adjusted mean changes from baseline to day 27 in UGE were 40.8, 77.1, 80.9, 93.0 and -2.1 g (P < 0.0001 for all empagliflozin groups vs placebo). Adjusted mean changes from baseline to day 28 in FPG were -1.56, -1.96, -2.31, -2.37 and -0.86 mmol/L (P < 0.01 for all empagliflozin groups vs placebo). Adjusted mean changes from baseline to day 27 in eight-point glucose profile were -1.96, -2.21, -2.42, -2.54 and -0.97 mmol/L (P < 0.01 for all empagliflozin groups vs placebo). Empagliflozin reached peak plasma concentration 1.5-2 h after dosing. Mean steady state terminal elimination half-lives ranged from 13.2 to 18.0 h. Of 100 patients, 25 experienced an adverse event, occurring more frequently for empagliflozin (29.1%) than placebo (9.5%); frequency was not dose related. CONCLUSIONS: In Japanese patients with type 2 diabetes mellitus, empagliflozin at doses up to 25 mg once daily for 4 weeks was well tolerated and resulted in significant improvements in glycemic control compared with placebo. This trial was registered with ClinicalTrials.gov (no. NCT00885118). AIMS: To evaluate the effects of the sodium glucose cotransporter 2 (SGLT2) inhibitor empagliflozin added to metformin for 12 weeks in patients with type 2 diabetes. METHODS: This dose-ranging, double-blind, placebo-controlled trial randomized 495 participants with type 2 diabetes inadequately controlled on metformin [haemoglobin A1c (HbA1c) >7 to ≤10%] to receive 1, 5, 10, 25, or 50 mg empagliflozin once daily (QD), or placebo, or open-label sitagliptin (100 mg QD), added to metformin for 12 weeks. The primary endpoint was change in HbA1c from baseline to week 12 (empagliflozin groups versus placebo). RESULTS: Reductions in HbA1c of -0.09 to -0.56% were observed with empagliflozin after 12 weeks, versus an increase of 0.15% with placebo (baseline: 7.8-8.1%). Compared with placebo, empagliflozin doses from 5 to 50 mg resulted in reductions in fasting plasma glucose (-2 to -28 mg/dl vs. 5 mg/dl with placebo; p < 0.0001) and body weight (-2.3 to -2.9 kg vs. -1.2 kg; p < 0.01). Frequency of adverse events was generally similar with empagliflozin (29.6-48.6%), placebo (36.6%) and sitagliptin (35.2%). Hypoglycaemia rates were very low and balanced among groups. Most frequent adverse events with empagliflozin were urinary tract infections (4.0% vs. 2.8% with placebo) and pollakiuria (2.5% vs. 1.4% with placebo). Genital infections were reported only with empagliflozin (4.0%). CONCLUSIONS: Once daily empagliflozin as add-on therapy to metformin was well tolerated except for increased genital infections and resulted in reductions in HbA1c, fasting plasma glucose and body weight in patients with type 2 diabetes inadequately controlled on metformin monotherapy. Empagliflozin, (2S,3R,4R,5S,6R)-2-[4-chloro-3-[[4-[(3S)-oxolan-3-yl]oxyphenyl]methyl]phenyl]-6-(hydroxymethyl)oxane-3,4,5-triol was recently approved by the FDA for the treatment of chronic type 2 diabetes mellitus. Herein, we report the synthesis of carbon-13 and carbon-14 labeled empagliflozin. Carbon-13 labeled empagliflozin was prepared in five steps and in 34% overall chemical yield starting from the commercially available α-D-glucose-[(13)C6]. For the radiosynthesis, the carbon-14 atom was introduced in three different positions of the molecule. In the first synthesis, Carbon-14 D-(+)-gluconic acid δ-lactone was used to prepare specifically labeled empagliflozin in carbon-1 of the sugar moiety in four steps and in 19% overall radiochemical yield. Carbon-14 labeled empagliflozin with the radioactive atom in the benzylic position was obtained in eight steps and in 7% overall radiochemical yield. In the last synthesis carbon-14 uniformly labeled phenol was used to give [(14)C]empagliflozin in eight steps and in 18% overall radiochemical yield. In all these radiosyntheses, the specific activities of the final compounds were higher than 53 mCi/mmol, and the radiochemical purities were above 98.5%. BACKGROUND: Sodium-glucose cotransporter 2 (SGLT2) inhibitors lower glycemia by enhancing urinary glucose excretion. The physiologic response to pharmacologically induced acute or chronic glycosuria has not been investigated in human diabetes. METHODS: We evaluated 66 patients with type 2 diabetes (62 ± 7 years, BMI = 31.6 ± 4.6 kg/m(2), HbA1c = 55 ± 8 mmol/mol, mean ± SD) at baseline, after a single dose, and following 4-week treatment with empagliflozin (25 mg). At each time point, patients received a mixed meal coupled with dual-tracer glucose administration and indirect calorimetry. RESULTS: Both single-dose and chronic empagliflozin treatment caused glycosuria during fasting (median, 7.8 [interquartile range {IQR}, 4.4] g/3 hours and 9.2 [IQR, 5.2] g/3 hours) and after meal ingestion (median, 29.0 [IQR, 12.5] g/5 hours and 28.2 [IQR, 15.4] g/5 hours). After 3 hours of fasting, endogenous glucose production (EGP) was increased 25%, while glycemia was 0.9 ± 0.7 mmol/l lower (P < 0.0001 vs. baseline). After meal ingestion, glucose and insulin AUC decreased, whereas the glucagon response increased (all P < 0.001). While oral glucose appearance was unchanged, EGP was increased (median, 40 [IQR, 14] g and 37 [IQR, 11] g vs. 34 [IQR, 11] g, both P < 0.01). Tissue glucose disposal was reduced (median, 75 [IQR, 16] g and 70 [IQR, 21] g vs. 93 [IQR, 18] g, P < 0.0001), due to a decrease in both glucose oxidation and nonoxidative glucose disposal, with a concomitant rise in lipid oxidation after chronic administration (all P < 0.01). β Cell glucose sensitivity increased (median, 55 [IQR, 35] pmol • min(-1) • m(-2) • mM(-1) and 55 [IQR, 39] pmol • min(-1) • m(-2) • mM(-1) vs. 44 [IQR, 32] pmol • min(-1) • m(-2) • mM(-1), P < 0.0001), and insulin sensitivity was improved. Resting energy expenditure rates and those after meal ingestion were unchanged. CONCLUSIONS: In patients with type 2 diabetes, empagliflozin-induced glycosuria improved β cell function and insulin sensitivity, despite the fall in insulin secretion and tissue glucose disposal and the rise in EGP after one dose, thereby lowering fasting and postprandial glycemia. Chronic dosing shifted substrate utilization from carbohydrate to lipid. Trial registration. ClinicalTrials.Gov NCT01248364 (EudraCT no. 2010-018708-99). Funding. This study was funded by Boehringer Ingelheim. Although several treatment options are available to reduce hyperglycemia, only about half of individuals with diagnosed diabetes mellitus (DM) achieve recommended glycemic targets. New agents that reduce blood glucose concentrations by novel mechanisms and have acceptable safety profiles are needed to improve glycemic control and reduce the complications associated with type 2 diabetes mellitus (T2DM). The renal sodium-glucose co-transporter 2 (SGLT2) is responsible for reabsorption of most of the glucose filtered by the kidney. Inhibitors of SGLT2 lower blood glucose independent of the secretion and action of insulin by inhibiting renal reabsorption of glucose, thereby promoting the increased urinary excretion of excess glucose. Canagliflozin, dapagliflozin, and empagliflozin are SGLT2 inhibitors approved as treatments for T2DM in the United States, Europe, and other countries. Canagliflozin, dapagliflozin, and empagliflozin increase renal excretion of glucose and improve glycemic parameters in patients with T2DM when used as monotherapy or in combination with other antihyperglycemic agents. Treatment with SGLT2 inhibitors is associated with weight reduction, lowered blood pressure, and a low intrinsic propensity to cause hypoglycemia. Overall, canagliflozin, dapagliflozin, and empagliflozin are well tolerated. Cases of genital infections and, in some studies, urinary tract infections have been more frequent in canagliflozin-, dapagliflozin-, and empagliflozin-treated patients compared with those receiving placebo. Evidence from clinical trials suggests that SGLT2 inhibitors are a promising new treatment option for T2DM. BACKGROUND: Diabetes is a leading cause of chronic kidney disease (CKD) worldwide. Optimum glycaemic control in patients with type 2 diabetes is important to minimise the risk of microvascular and macrovascular complications and to slow the progression of CKD. We assessed the efficacy and safety of empagliflozin as an add-on treatment in patients with type 2 diabetes and CKD. METHODS: We did a phase 3, randomised, double-blind, parallel-group, placebo-controlled trial at 127 centres in 15 countries. Patients with HbA1c of 7% or greater to 10% or less were eligible for inclusion. Patients with stage 2 CKD (estimated glomerular filtration rate [eGFR] ≥60 to <90 mL/min per 1·73 m(2); n=290) were randomly assigned (1:1:1) to receive empagliflozin 10 mg or 25 mg or placebo once daily for 52 weeks. Patients with stage 3 CKD (eGFR ≥30 to <60 mL/min per 1·73 m(2); n=374) were randomly assigned (1:1) to receive empagliflozin 25 mg or placebo for 52 weeks. Randomisation was done with a computer-generated random sequence and stratified by renal impairment, HbA1c, and background antidiabetes medication. Treatment assignment was masked from patients and investigators. The primary endpoint was change from baseline in HbA1c at week 24 by ANCOVA in the full analysis set. This study is registered with ClinicalTrials.gov, number NCT01164501. FINDINGS: In patients with stage 2 CKD, adjusted mean treatment differences versus placebo in changes from baseline in HbA1c at week 24 were -0·52% (95% CI -0·72 to -0·32) for empagliflozin 10 mg and -0·68% (-0·88 to -0·49) for empagliflozin 25 mg (both p<0·0001). In patients with stage 3 CKD, adjusted mean treatment difference versus placebo in change from baseline in HbA1c at week 24 was -0·42% (-0·56 to -0·28) for empagliflozin 25 mg (p<0·0001). In patients with stage 2 CKD, adverse events were reported over 52 weeks by 83 patients (87%) on placebo (15 severe [16%] and 11 serious [12%]), 86 (88%) on empagliflozin 10 mg (six severe [6%] and six serious [6%]) and 78 (80%) on empagliflozin 25 mg (eight severe [8%] and seven serious [7%]). In patients with stage 3 CKD, adverse events were reported over 52 weeks by 156 patients (83%) on placebo (15 severe [8%] and 23 serious [12%]) and 156 (83%) on empagliflozin 25 mg (18 severe [10%] and 22 serious [12%]). INTERPRETATION: In patients with type 2 diabetes and stage 2 or 3 CKD, empagliflozin reduced HbA1c and was well tolerated. However, our findings might not be applicable to the general population of patients with type 2 diabetes and renal impairment. FUNDING: Boehringer Ingelheim, Eli Lilly. AIMS: To provide model-based clinical development decision support including dose selection guidance for empagliflozin, an orally administered sodium glucose cotransporter 2 inhibitor, through developed exposure-response (E-R) models for efficacy and tolerability in patients with type 2 diabetes mellitus (T2DM). METHODS: Five randomized, placebo-controlled, multiple oral dose studies of empagliflozin in patients with T2DM (n = 974; 1-100 mg once daily, duration ≤12 weeks) were used to develop E-R models for efficacy (glycosylated haemoglobin [HbA1c ], fasting plasma glucose [FPG] and urinary glucose excretion). Two studies (n = 748, 12 weeks) were used to evaluate tolerability E-R. RESULTS: The efficacy model predicted maximal decreases in FPG and HbA1c of 16% and 0.6%, respectively, assuming a baseline FPG concentration of 8 mm (144 mg dl(-1) ) and 10-25 mg every day empagliflozin targeted 80-90% of these maximums. Increases in exposure had no effect on incidence rates of hypoglycaemia (n = 4), urinary tract infection (n = 17) or genital/vulvovaginal-related (n = 16) events, although low prevalence rates may have precluded more accurate evaluation. CONCLUSIONS: E-R analyses indicated that 10 and 25 mg once daily empagliflozin doses achieved near maximal glucose lowering efficacy. Type 2 diabetes is increasing in prevalence worldwide, and hyperglycemia is often poorly controlled despite a number of therapeutic options. Unlike previously available agents, sodium-glucose co-transporter 2 (SGLT2) inhibitors offer an insulin-independent mechanism for improving blood glucose levels, since they promote urinary glucose excretion (UGE) by inhibiting glucose reabsorption in the kidney. In addition to glucose control, SGLT2 inhibitors are associated with weight loss and blood pressure reductions, and do not increase the risk of hypoglycemia. Empagliflozin is a selective inhibitor of SGLT2, providing dose-dependent UGE increases in healthy volunteers, with up to 90 g of glucose excreted per day. It can be administered orally, and studies of people with renal or hepatic impairment indicated empagliflozin needed no dose adjustment based on pharmacokinetics. In Phase II trials in patients with type 2 diabetes, empagliflozin provided improvements in glycosylated hemoglobin (HbA1c) and other measures of glycemic control when given as monotherapy or add-on to metformin, as well as reductions in weight and systolic blood pressure. As add-on to basal insulin, empagliflozin not only improved HbA1c levels but also reduced insulin doses. Across studies, empagliflozin was generally well tolerated with a similar rate of hypoglycemia to placebo; however, patients had a slightly increased frequency of genital infections, but not urinary tract infections, versus placebo. Phase III studies have also reported a good safety profile along with significant improvements in HbA1c, weight and blood pressure, with no increased risk of hypoglycemia versus placebo. Based on available data, it appears that empagliflozin may be a useful option in a range of patients; however, clinical decisions will be better informed by the results of ongoing studies, in particular, a large cardiovascular outcome study (EMPA-REG OUTCOME™). OBJECTIVE: To investigate the long-term safety and efficacy of empagliflozin, a sodium glucose cotransporter 2 inhibitor; sitagliptin; and metformin in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: In this randomized, open-label, 78-week extension study of two 12-week, blinded, dose-finding studies of empagliflozin (monotherapy and add-on to metformin) with open-label comparators, 272 patients received 10 mg empagliflozin (166 as add-on to metformin), 275 received 25 mg empagliflozin (166 as add-on to metformin), 56 patients received metformin, and 56 patients received sitagliptin as add-on to metformin. RESULTS: Changes from baseline in HbA1c at week 90 were -0.34 to -0.63% (-3.7 to -6.9 mmol/mol) with empagliflozin, -0.56% (-6.1 mmol/mol) with metformin, and -0.40% (-4.4 mmol/mol) with sitagliptin. Changes from baseline in weight at week 90 were -2.2 to -4.0 kg with empagliflozin, -1.3 kg with metformin, and -0.4 kg with sitagliptin. Adverse events (AEs) were reported in 63.2-74.1% of patients on empagliflozin and 69.6% on metformin or sitagliptin; most AEs were mild or moderate in intensity. Hypoglycemic events were rare in all treatment groups, and none required assistance. AEs consistent with genital infections were reported in 3.0-5.5% of patients on empagliflozin, 1.8% on metformin, and none on sitagliptin. AEs consistent with urinary tract infections were reported in 3.8-12.7% of patients on empagliflozin, 3.6% on metformin, and 12.5% on sitagliptin. CONCLUSIONS: Long-term empagliflozin treatment provided sustained glycemic and weight control and was well tolerated with a low risk of hypoglycemia in patients with type 2 diabetes. |
398 | Which are the main methods for pharmacophore modelling? | A pharmacophore describes the arrangement of molecular features a ligand must contain to efficaciously bind a receptor. Pharmacophore models are developed to improve molecular understanding of ligand–protein interactions, and can be used as a tool to identify novel compounds that fulfil the pharmacophore requirements and have a high probability of being biologically active. Protein structure-based pharmacophores (SBPs) derive these molecular features by conversion of protein properties to reciprocal ligand space. Unlike ligand-based pharmacophore models, which require templates of ligands in their bioactive conformation, SBPs do not depend on ligand information. | [23957390, 22650262, 23651479, 15807512, 23651482, 23651486, 23675939, 21400356, 23334436, 23862697, 16996282, 23621564, 24504131, 18410307, 20362693, 16783689, 23933279, 22380004, 24266725, 21521148] | 505 | Protein:protein interactions are becoming increasingly significant as potential drug targets; however, the rational identification of small molecule inhibitors of such interactions remains a challenge. Pharmacophore modelling is a popular tool for virtual screening of compound libraries, and has previously been successfully applied to the discovery of enzymatic inhibitors. However, the application of pharmacophore modelling in the field of protein:protein interaction inhibitors has historically been considered more of a challenge and remains limited. In this review, we explore the interaction mimicry by known inhibitors that originate from in vitro screening, demonstrating the validity of pharmacophore mapping in the generation of queries for virtual screening. We discuss the pharmacophore mapping methods that have been successfully employed in the discovery of first-in-class inhibitors. These successful cases demonstrate the usefulness of a "tool kit" of diverse strategies for application across a range of situations depending on the available structural information. Generation of reliable pharmacophore models is a key strategy in drug design. The quality of a pharmacophore model is known to depend on several factors, with the quality of the conformer sets used perhaps being one of the most important. The goal of this study was to compare different conformational analysis methods to determine if one was superior to the others for pharmacophore generation using Catalyst/HypoGen. The five methods selected were Catalyst/Fast, Catalyst/Best, Omega, Chem-X and MacroModel. Data sets for which Catalysts models had previously been published were selected using defined quality measures. Hypotheses were generated for each of the data sets and the performance of the different conformational analysis methods was compared using both quantitative (cost and correlation coefficients) and qualitative measures (by comparing the hypotheses in terms of the features present and their spatial relationships). Two main conclusions emerged from the study. First, it was not always possible to replicate the literature results. The reasons for these failures are explored in detail, and a template for use in publications that apply the Catalyst methodology is proposed. Second, the faster rule-based methods for conformational analysis give pharmacophore models that are just as good as, and in some cases better than, the models generated using the slower, more rigorous approaches. A pharmacophore model does not describe a real molecule or a real association of functional groups but illustrates a molecular recognition of a biological target shared by a group of compounds. Pharmacophores also represent the spatial arrangement of essential interactions in a receptor-binding pocket. Structure based pharmacophores (SBPs) can work both with a free (apo) structure or a macromolecule-ligand complex (holo) structure. The SBP methods that derive pharmacophore from protein-ligand complexes use the potential interactions observed between ligand and protein, whereas, the SBP method that aims to derive pharmacophore from ligand free protein, uses only protein active site information. Therefore SBPs do not encounter to challenging problems such as ligand flexibility, molecular alignment as well as proper selection of training set compounds in ligand based pharmacophore modeling. The current review deals with Hot Spot' analysis of binding site to feature generation, several approaches to feature reduction, and considers shape and excluded volumes to SBP model building. This review continues to represent several applications of SBPs in virtual screening especially in parallel screening approach and multi-target drug design. Also it reports the applications of SBPs in QSAR. This review emphasizes that SBPs are valuable tools for hit to lead optimization, virtual screening, scaffold hopping, and multi-target drug design. Pharmacophore approaches have evolved to be one of the most successful tools in drug discovery, especially since the past two decades. 3D pharmacophore methods are now commonly used as part of more complex workflows in drug discovery campaigns, and have been successfully and extensively applied in virtual screening (VS) approaches. This review provides a perspective of how to assess the performance of 3D pharmacophore models to be used in VS. Since 3D VS protocols are in general assessed by their ability to discriminate between active and inactive compounds, we summarize the impact of the composition and preparation of modeling and external sets on the outcome of evaluations. Moreover, we highlight the significance of both classic enrichment parameters and advanced descriptors for the performance of 3D pharmacophore-based virtual screening methods. One of the major reasons for late-stage failure of drug candidates is due to problems uncovered in pharmacokinetics during clinical trials. There is now a general consensus for earlier consideration of these effects in the drug discovery process. Computer-aided design technology provides us with tools to develop predictive models for such pharmacokinetic properties. Among these tools, we focus on pharmacophore modeling techniques in this article. Pharmacophore models that are reported for various cytochrome P450 (CYP) enzymes are reviewed for the isoenzymes CYP1A2, 2B6, 2C9, 2C19, 2D6, 2E1, and 3A4. In addition pharmacophore models for related metabolic processes through CYP19 (aromatase), CYP51 (14.α-lanosterol demethylase), PXR (pregnane X-receptor), and finally for human intrinsic clearance are also reviewed. The models reported by various scientists are schematically represented in the figures in order to visually demonstrate their similarities and differences. The models developed by different researchers or sometimes even by the same research group for different sets of ligands, provide a clear picture of the challenges in coming up with a single model with good predictive values. One of the main reasons for this challenge is related to relatively large size of the active sites and flexibility of the CYP isoenzymes, which results in multiple binding sites. We propose development of multiple- diverse pharmacophore models for each binding mode (as opposed to a single predictive model for each CYP isoenzyme). After scoring and prioritization of the models, we propose the use of a battery of pharmacophore models for each CYP isoenzyme binding mode to computationally obtain a P450 interaction profile for drug candidates early in the drug development cycle, when decisions on their fate can be made before incurring the costs of synthesis and testing. A pharmacophore model has been developed using diverse classes of epidermal growth factor receptor (EGFR) tyrosine kinase (TK) inhibitors useful in the treatment of human tumours. Among the top 10 generated hypotheses, the second hypothesis, with one hydrogen bond acceptor, one ring aromatic and three hydrophobic features, was found to be the best on the basis of Cat Scramble validation as well as test set prediction (r(training) = 0.89, r(test) = 0.82). The model also maps well to the external test set molecules as well as clinically active molecules and corroborates the docking studies. Finally, 10 hits were identified as potential leads after virtual screening of ZINC database for EGFR TK inhibition. The study may facilitate the designing and discovery of novel EGFR TK inhibitors. Acetyl-CoA carboxylase (ACC) is a crucial metabolic enzyme that plays a vital role in obesity-induced type 2 diabetes and fatty acid metabolism. To identify dual inhibitors of Acetyl-CoA carboxylase1 and Acetyl-CoA carboxylase2, a pharmacophore modelling approach has been employed. The best HypoGen pharmacophore model for ACC2 inhibitors (Hypo1_ACC2) consists of one hydrogen bond acceptor, one hydrophobic aliphatic and one hydrophobic aromatic feature, whereas the best pharmacophore (Hypo1_ACC1) for ACC1 consists of one additional hydrogen-bond donor (HBD) features. The best pharmacophore hypotheses were validated by various methods such as test set, decoy set and Cat-Scramble methodology. The validated pharmacophore models were used to screen several small-molecule databases, including Specs, NCI, ChemDiv and Natural product databases to identify the potential dual ACC inhibitors. The virtual hits were then subjected to several filters such as estimated [Formula: see text] value, quantitative estimation of drug-likeness and molecular docking analysis. Finally, three novel compounds with diverse scaffolds were selected as potential starting points for the design of novel dual ACC inhibitors. Accurate prediction of ligand-binding poses is crucial for understanding molecular interactions and is very important for drug discovery, structural design, and optimization. In this study, we developed a novel scoring program, HotLig, which applies the Connolly surface of a protein to calculate hydrophobic interaction and paired pharmacophore interactions with ligands. In addition to molecular surface distance, ligand-contacting areas and hydrogen-bond angles were also introduced to the scoring functions in HotLig. Four individual energy scoring functions for H-bonds, ionic pairs, metal coordination, and hydrophobic effects were derived from 600 protein-ligand complexes, and then, their weighting factors were optimized through an interaction-characterized training set. Success rates of ligand-binding-pose predictions (with a root mean squared deviation of ≤2 Å) for the Wang, GOLD, and Cheng data sets were respectively validated to be 91.0%, 87.0%, and 85.6%. HotLig was found to possess equally good predictive powers for the hydrophilic (88.6%) and hydrophobic subsets (87.5%), and the success rate for the mixed subset was as high as 96.9%. The Spearman correlation coefficients were as good as 0.609 to 0.668, which indicates HotLig also has satisfactory predictive power for binding affinities. These results suggested that the HotLig can analyze diverse ligands, including peptides, and is expected to be a powerful tool for drug design and discovery. Aminoacyl-tRNA synthetases (aaRSs) are essential enzymes involved in protein biosynthesis in all living organisms and are an unexploited antibacterial targets, as many strains of bacteria have become resistant to all established classes of antibiotics. Therefore, the main aim of this study is to discover new lead molecules which would be useful as anti-bacterial compounds. Pharmacophore models were developed by using CATALYST HypoGen with a training set of 29 diverse methionyl-tRNA synthetase (MetRS) inhibitors. The best quantitative pharmacophore hypothesis (Hypo1) obtained a correlation coefficient of 0.975, root mean square deviation (RMSD) of 0.55 and cost difference (null cost-total cost) of 70.32. This Hypo1 was validated by two methods, first by using 104 test set molecules which resulted a correlation of 0.926 between HypoGen estimated activities versus experimental activities and secondly by Cat-Scramble validation method. This validated pharmacophore model was further used for screening databases for discovery of new MetRS inhibitors. The new lead compounds were further analyzed for drug-like properties. Homology modeled structure of Staphylococcus aureus MetRS was built and molecular docking studies were performed with many inhibitors using the newly built protein structure. Finally, it was found that the new leads exhibited good estimated inhibitory activity, calculated binding properties similar to experimentally proven compounds and also favorable drug-like properties. Protein-based pharmacophore models derived from protein binding site atoms without the inclusion of any ligand information have become more popular in virtual screening studies. However, the accuracy of protein-based pharmacophore models for reproducing the critical protein-ligand interactions has never been explicitly assessed. In this study, we used known protein-ligand contacts from a large set of experimentally determined protein-ligand complexes to assess the quality of the protein-based pharmacophores in reproducing these critical contacts. We demonstrate how these contacts can be used to optimize the pharmacophore generation procedure to produce pharmacophore models that optimally cover the known protein-ligand interactions. Finally, we explored the potential of the optimized protein-based pharmacophore models for pose prediction and pose rankings. Our results demonstrate that there are significant variations in the success of protein-based pharmacophore models to reproduce native contacts and consequently native ligand poses dependent on the details of the pharmacophore generation process. We show that the generation of optimized protein-based pharmacophore models is a promising approach for ligand pose prediction and pose rankings. Aurora-A has been identified as one of the most attractive targets for cancer therapy and a considerable number of Aurora-A inhibitors have been reported recently. In order to clarify the essential structure-activity relationship for the known Aurora-A inhibitors as well as identify new lead compounds against Aurora-A, 3D pharmacophore models were developed based on the known inhibitors. The best hypothesis, Hypo1, was used to screen molecular structural databases, including Specs and China Natural Products Database for potential lead compounds. The hit compounds were subsequently subjected to filtering by Lipinski's rules and docking study to refine the retrieved hits and as a result to reduce the rate of false positive. Finally, 39 compounds were purchased for further in vitro assay against several human tumour cell lines including A549, MCF-7, HepG2 and PC-3, in which Aurora-A is overexpressed. Two compounds show very low micromolar inhibition potency against some of these tumour cells. And they have been selected for further investigation. Pharmacophore approaches have become one of the major tools in drug discovery after the past century's development. Various ligand-based and structure-based methods have been developed for improved pharmacophore modeling and have been successfully and extensively applied in virtual screening, de novo design and lead optimization. Despite these successes, pharmacophore approaches have not reached their expected full capacity, particularly in facing the demand for reducing the current expensive overall cost associated with drug discovery and development. Here, the challenges of pharmacophore modeling and applications in drug discovery are discussed and recent advances and latest developments are described, which provide useful clues to the further development and application of pharmacophore approaches. Whereas computational methods for molecular design are well established in medicinal chemistry research, their application in the field of natural products is still not exhaustively explored. This article gives a short introduction into both the potential for the application of computer-assisted approaches, such as pharmacophore modelling, virtual screening, docking, and neural networking to efficiently access the bioactive metabolites, and the requirements and limitations related to this specific field. The challenge is which selection criteria and/or multiple filtering tools to apply for a target-oriented isolation of potentially bioactive secondary metabolites. Application examples are provided where in silico tools and classical methods used by natural product scientists are used in an effort to maximize their efficacy in drug discovery. Thus, integrated computer-assisted strategies may help to process the huge amount of available structural and biological information in a reasonably short time for a straightforward search of bioactive natural products. Herein, a combined molecular docking-based and pharmacophore-based target prediction strategy is presented, in which a probabilistic fusion method is suggested for target ranking. Establishment and validation of the combined strategy are described. A target database, termed TargetDB, was firstly constructed, which contains 1105 drug targets. Based on TargetDB, the molecular docking-based target prediction and pharmacophore-based target prediction protocols were established. A probabilistic fusion method was then developed by constructing probability assignment curves (PACs) against a set of selected targets. Finally the workflow for the combined molecular docking-based and pharmacophore-based target prediction strategy was established. Evaluations of the performance of the combined strategy were carried out against a set of structurally different single-target compounds and a well-known multi-target drug, 4H-tamoxifen, which results showed that the combined strategy consistently outperformed the sole use of docking-based and pharmacophore-based methods. Overall, this investigation provides a possible way for improving the accuracy of in silico target prediction and a method for target ranking. Recent technological breakthroughs in medicinal chemistry arena had ameliorated the perspectives of quantitative structure-activity relationship (QSAR) methods. In this direction, we developed a group-based QSAR method based on pharmacophore-similarity concept which takes into account the 2D topological pharmacophoric descriptors and predicts the group-specific biological activities. This activity prediction may assist the contribution of certain pharmacophore features encoded by respective fragments toward activity improvement and/or detrimental effects. We termed this method as pharmacophore-similarity-based QSAR (PS-QSAR) and studied the activity contribution of fragments from 3-hydroxypyridinones derivatives possessing antimalarial activities. A pharmacophore is a model which represents the key physico-chemical interactions that mediate biological activity. There is a long history of using pharmacophore modeling methods to select subsets of compounds, focused towards a specific target of interest. This paper will review existing computational methods for deriving and comparing pharmacophore models. We outline a new classification of pharmacophore methods based on the abstraction of the underlying chemical interactions which embody a pharmacophore, and the methods available to quantitatively compare them. Within the context of this classification, example studies, using specific pharmacophore modeling methods for focused library selection, will be discussed. |
399 | Are there conserved noncoding elements identified between genomes of human and teleosts? | Vertebrate genomes contain thousands of conserved noncoding elements (CNEs) that often function as tissue-specific enhancers. In this study, we have identified CNEs in human, dog, chicken, Xenopus, and four teleost fishes (zebrafish, stickleback, medaka, and fugu) using elephant shark, a cartilaginous vertebrate, as the base genome and investigated the evolution of these ancient vertebrate CNEs (aCNEs) in bony vertebrate lineages | [19562753, 16556802, 21081479, 17387144, 17617896, 19095434, 19782672, 18047696] | 506 | Fibroblast growth factors (Fgfs) encode small signaling proteins that help regulate embryo patterning. Fgfs fall into seven families, including FgfD. Nonvertebrate chordates have a single FgfD gene; mammals have three (Fgf8, Fgf17, and Fgf18); and teleosts have six (fgf8a, fgf8b, fgf17, fgf18a, fgf18b, and fgf24). What are the evolutionary processes that led to the structural duplication and functional diversification of FgfD genes during vertebrate phylogeny? To study this question, we investigated conserved syntenies, patterns of gene expression, and the distribution of conserved noncoding elements (CNEs) in FgfD genes of stickleback and zebrafish, and compared them with data from cephalochordates, urochordates, and mammals. Genomic analysis suggests that Fgf8, Fgf17, Fgf18, and Fgf24 arose in two rounds of whole genome duplication at the base of the vertebrate radiation; that fgf8 and fgf18 duplications occurred at the base of the teleost radiation; and that Fgf24 is an ohnolog that was lost in the mammalian lineage. Expression analysis suggests that ancestral subfunctions partitioned between gene duplicates and points to the evolution of novel expression domains. Analysis of CNEs, at least some of which are candidate regulatory elements, suggests that ancestral CNEs partitioned between gene duplicates. These results help explain the evolutionary pathways by which the developmentally important family of FgfD molecules arose and the deduced principles that guided FgfD evolution are likely applicable to the evolution of developmental regulation in many vertebrate multigene families. Evolutionary sequence conservation is an accepted criterion to identify noncoding regulatory sequences. We have used a transposon-based transgenic assay in zebrafish to evaluate noncoding sequences at the zebrafish ret locus, conserved among teleosts, and at the human RET locus, conserved among mammals. Most teleost sequences directed ret-specific reporter gene expression, with many displaying overlapping regulatory control. The majority of human RET noncoding sequences also directed ret-specific expression in zebrafish. Thus, vast amounts of functional sequence information may exist that would not be detected by sequence similarity approaches. We report evidence for a mechanism for the maintenance of long-range conserved synteny across vertebrate genomes. We found the largest mammal-teleost conserved chromosomal segments to be spanned by highly conserved noncoding elements (HCNEs), their developmental regulatory target genes, and phylogenetically and functionally unrelated "bystander" genes. Bystander genes are not specifically under the control of the regulatory elements that drive the target genes and are expressed in patterns that are different from those of the target genes. Reporter insertions distal to zebrafish developmental regulatory genes pax6.1/2, rx3, id1, and fgf8 and miRNA genes mirn9-1 and mirn9-5 recapitulate the expression patterns of these genes even if located inside or beyond bystander genes, suggesting that the regulatory domain of a developmental regulatory gene can extend into and beyond adjacent transcriptional units. We termed these chromosomal segments genomic regulatory blocks (GRBs). After whole genome duplication in teleosts, GRBs, including HCNEs and target genes, were often maintained in both copies, while bystander genes were typically lost from one GRB, strongly suggesting that evolutionary pressure acts to keep the single-copy GRBs of higher vertebrates intact. We show that loss of bystander genes and other mutational events suffered by duplicated GRBs in teleost genomes permits target gene identification and HCNE/target gene assignment. These findings explain the absence of evolutionary breakpoints from large vertebrate chromosomal segments and will aid in the recognition of position effect mutations within human GRBs. BACKGROUND: Embryonic development is coordinated by sets of cis-regulatory elements that are collectively responsible for the precise spatio-temporal organization of regulatory gene networks. There is little information on how these elements, which are often associated with highly conserved noncoding sequences, are combined to generate precise gene expression patterns in vertebrates. To address this issue, we have focused on Six3, an important regulator of vertebrate forebrain development. RESULTS: Using computational analysis and exploiting the diversity of teleost genomes, we identified a cluster of highly conserved noncoding sequences surrounding the Six3 gene. Transgenesis in medaka fish demonstrates that these sequences have enhancer, silencer, and silencer blocker activities that are differentially combined to control the entire distribution of Six3. CONCLUSION: This report provides the first example of the precise regulatory code necessary for the expression of a vertebrate gene, and offers a unique framework for defining the interplay of trans-acting factors that control the evolutionary conserved use of Six3. Teleost fishes are the largest and most diverse group of vertebrates. The diversity of teleosts has been attributed to a whole-genome duplication (WGD) event in the ray-finned fish lineage. Recent comparative genomic studies have revealed that teleost genomes have experienced frequent gene-linkage disruptions compared to other vertebrates, and that protein-coding sequences in teleosts are evolving faster than in mammals, irrespective of their duplication status. A significant number of conserved noncoding elements (CNEs) shared between cartilaginous fishes and tetrapods have diverged beyond recognition in teleost fishes. The divergence of CNEs seems to have been initiated in basal ray-finned fishes before the WGD. The fast evolving singleton and duplicated genes as well as the divergent CNEs might have contributed to the diversity of teleost fishes. A large-scale enhancer detection screen was performed in the zebrafish using a retroviral vector carrying a basal promoter and a fluorescent protein reporter cassette. Analysis of insertional hotspots uncovered areas around developmental regulatory genes in which an insertion results in the same global expression pattern, irrespective of exact position. These areas coincide with vertebrate chromosomal segments containing identical gene order; a phenomenon known as conserved synteny and thought to be a vestige of evolution. Genomic comparative studies have found large numbers of highly conserved noncoding elements (HCNEs) spanning these and other loci. HCNEs are thought to act as transcriptional enhancers based on the finding that many of those that have been tested direct tissue specific expression in transient or transgenic assays. Although gene order in hox and other gene clusters has long been known to be conserved because of shared regulatory sequences or overlapping transcriptional units, the chromosomal areas found through insertional hotspots contain only one or a few developmental regulatory genes as well as phylogenetically unrelated genes. We have termed these regions genomic regulatory blocks (GRBs), and show that they underlie the phenomenon of conserved synteny through all sequenced vertebrate genomes. After teleost whole genome duplication, a subset of GRBs were retained in two copies, underwent degenerative changes compared with tetrapod loci that exist as single copy, and that therefore can be viewed as representing the ancestral form. We discuss these findings in light of evolution of vertebrate chromosomal architecture and the identification of human disease mutations. |