In India, most snakebite envenomation (SBE) incidents are caused by the “Big Four” snakes which include Russell’s viper, common krait, Indian cobra, and saw-scaled viper. Their common envenomation effects include neurotoxicity, myotoxicity, and coagulopathy. However, they also induce rare complications such as priapism, pseudoaneurysm, and sialolithiasis. Ocular manifestations such as optic neuritis develop rarely following envenomations by non-spitting snakes and they may cause temporary vision changes and blindness if untreated. While optic neuritis following Indian cobra envenomation has been reported previously, this was not encountered in victims of common kraits. Hence, for the first time, we report optic neuritis developed in a victim following envenomation by a common krait and compare its clinical features and diagnostic and therapeutic methods used with another case of optic neuritis in a victim of an Indian cobra bite. Both patients received antivenom treatment and made an initial recovery; however, optic neuritis developed several days later. The condition was diagnosed using ophthalmic examination together with computed tomography and/or magnetic resonance imaging methods. Due to very similar clinical features, both patients received intravenous corticosteroids which restored their vision and successfully treated optic neuritis. This case report suggests that the optic neuritis developed in a common krait envenomation is comparable to the one developed following a cobra bite, and therefore, the same diagnostic and therapeutic approaches can be used. This study also raises awareness of this rare complication and provides guidance for the diagnosis and treatment of SBE-induced optic neuritis. Daboia russelii), Indian cobra (Naja naja), saw-scaled viper (Echis carinatus), and common krait (Bungarus caeruleus) [Venomous snakebites are common in South and Southeast Asia, Africa, as well as in Central and South America . The sigeruleus) . SBE viceruleus) ,6. The eeruleus) . Howevereruleus) , spleen eruleus) , Wunderleruleus) , pseudoaeruleus) , and siaeruleus) .Optic neuritis is a frequently observed clinical condition that occurs due to the inflammation of optic nerves . This coPatient 1, a healthy 32-year-old female homemaker, was bitten by an Indian cobra on her right foot. She developed bilateral ptosis and respiratory depression within 30 min following the bite. After evaluation in a local hospital, she was treated with an intravenous infusion of 10 vials (100 mL) of polyvalent antivenom raised against the Indian ‘Big Four’ snakes as well as neostigmine and atropine. Although she improved, on the fifth day after the bite, she complained of decreased vision in both eyes and therefore was referred to the emergency department of our hospital. The patient arrived at the emergency department without any neurological deficits. However, an ophthalmic examination of both eyes revealed sluggish pupillary reactions to light, papilledema A, and thPatient 2, a 30-year-old male farmer, was bitten by a common krait while working on his farmland. He was transported to the emergency department within one hour following the bite. He was unconscious and in respiratory distress upon admission. He was immediately intubated and started on mechanical ventilation. He was intravenously administered 20 vials (200 mL) of polyvalent antivenom  raised against the Indian ‘Big Four’ snakes. His sensorium, muscle strength and oxygen saturation improved and were extubated two days after admission/bite. On the fourth day after the bite, he complained of blurred vision and diminished visual acuity similar to patient 1. So, he underwent a thorough neurological examination. His motor and sensory system examinations were normal without any signs of cerebellar dysfunction or meningeal irritation. His ophthalmic examination was notable for a visual acuity that was limited to the perception of light and round pupils but sluggishly reactive to light. His intraocular pressure was within normal limits and ocular motility and anterior segments were unremarkable. Fundoscopic examination revealed bilateral papilledema. The visual evoked potentials were indicative of maculopathy and bilateral axonopathic optic neuropathy consistent with optic neuritis. MRI of the brain revealed high-intensity changes in both optic nerves on T2-weighted images A and enlAnatomically, greater than one million axons of each optic nerve connect the rods and cones of each eye to the optic chiasm in the brain . The optNaja atra, Naja nigricollis, Naja pallida, and Hemachatus haemachatus from various geographical locations are known to induce ocular complications including optic neuritis. In many cases, optic neuritis developed a few or several days after envenomation. In some patients, simple water irrigation of the eyes was used to manage ocular damage, while in others, a range of treatment methods was used [Although SBE has been known to induce a plethora of local and systemic complications, ocular manifestations are rarely encountered following envenomations, specifically by non-spitting snake species. SBE-induced ocular complications include subconjunctival haemorrhage, AACG, CRAO, acute anterior uveitis, external ophthalmoplegia, exudative retinal detachment, photophobia, macular infarction, and optic neuritis . Severalwas used . While swas used . The impIn this study, we report a unique case of optic neuritis that developed in a patient following envenomation from a common krait and compare their clinical features with optic neuritis developed in another patient who was bitten by a cobra, both non-spitting elapid species. In both cases, optic neuritis developed a few days after the bite despite antivenom treatment. The subjective complaints of blurred vision in both scenarios prompted thorough neurological and ophthalmological examinations followed by CT and MRI scans which revealed the development of optic neuritis. Despite envenomations by two different snakes in these patients, the clinical features developed in both were very similar. Moreover, the use of MRI was beneficial in diagnosing optic neuritis and identifying the unique ‘polo-mint’ appearance of enlarged optic nerves in both patients. The envenomations from non-spitting cobras, including the Indian cobra, were previously reported to induce optic neuritis in a few cases. For example, an Indian cobra bite in a 50-year-old male caused diminished visual acuity on the sixth day after SBE and improved over the next few days . This paCrotalus atrox (which is known to spit venom in some cases) [Daboia russelii [Macrovipera lebetinus [Macrovipera lebetinus induced blurred vision and optic neuritis in a patient six days after the bite [In addition to elapid snake species, some vipers such as e cases) ,26, Daborusselii , and Macebetinus  as well ebetinus . In a Ruebetinus . In contthe bite . In two the bite ,30. Whil2 (PLA2) has been shown to induce anti-coagulant effects resulting in haemorrhage. Venom metalloproteases, PLA2 and L-amino acid oxidases can induce inflammatory responses [2 present in both elapid and viper venoms [There are several potential causes reported for the development of optic neuritis following SBE . For exaesponses . Therefoesponses  and may r venoms  are liker venoms . CadaverIt is apparent that envenoming by any venomous snake species including elapids, vipers, and colubrids can induce optic neuritis. Hence, this condition, as well as other ocular manifestations, are not only attributed to typical envenomations of spitting cobras. The clinicians who treat SBE should be aware of this complication arising from non-spitting snake species specifically several days after the bite despite antivenom administration. Fundoscopic examination as well as CT and/or MRI scans together with thorough ophthalmological and neurological examinations can be used to identify optic neuritis. As reported in most cases, intravenous administration of corticosteroids may be effective in treating this inflammatory condition. Although optic neuritis upon envenomation by non-spitting cobras was reported previously, the development of this condition in a patient with krait envenomation emphasises the need for further research in this area. Moreover, the molecular interactions of various venom toxins with the optic nerves and other components of the eyes should be studied in detail to establish the underlying molecular mechanisms. Finally, the impact of antivenom components in the development of this condition should be investigated as this may be another potential cause which could be resolved through further refinements to antivenoms.Both patients provided written informed consent to collect and publish the data presented in this article. The patients and their relatives were informed about the purpose of this study and its wider use in scientific and clinical communities to improve the clinical management of SBE. The identity of the offending snake species was confirmed by an experienced herpetologist by examining the dead specimens brought by the patients. The patients were diagnosed and treated as normal using standard protocols from the World Health Organisation and local health authorities. They received polyvalent antivenom raised against the Indian ‘Big Four’ snakes from Bharat Serum and Vaccines Limited, India. The diagnosis of optic neuritis was performed using standard ophthalmic and neurological examinations as well as using CT and MRI scanning equipment available within the hospital.


NXNL1) produces a truncated thioredoxin-like protein, RdCVF, by intron retention in rod photoreceptors of the retina. This protein prevents the secondary cone degeneration in animal models of rod-cone degeneration. Extracellular RdCVF binds to a complex at the surface of the cones, composed of the basigin-1, a photoreceptor specific alternative splicing product of the basigin gene, and GLUT1, the glucose transporter. RdCVF accelerates glucose uptake allosterically. Glucose is either metabolized by aerobic glycolysis to sustain cone outer segment renewal or by the pentose phosphate pathway to support redox power to the thioredoxin RdCVFL. RdCVF signaling predates the appearance of the eye and evolved through two alternative splicing events. RdCVF signaling is observed first in hydra where it regulates an unknown signaling. A scallop RdCVF protein is produced by ciliated photoreceptors of the retina and binds its receptor, BSG1, the first occurrence of RdCVF/BSG1 signaling. In the lamprey, RdCVF metabolic signaling between rod and cones is fully operational. In the mouse, the production of BSG1 is regulated through alternative splicing. This signaling was extended to other regions of the brain, via its paralogue NXNL2.We studied the origin of rod-derived cone viability factor (RdCVF) during evolution. In mammals, the nucleoredoxin-like 1 gene ( With only 2% of human body mass, the brain of an adult human uses about 15–20% of the body’s total glucose-derived energy . The bra15O (18F-fluorodeoxyglucose (FDG) was developed to quantify brain glucose metabolism by PET  , also called rod-cone degeneration is a genetically heterogeneous retinal degenerative disease characterized by the death of rod photoreceptors followed by the progressive loss of function and degeneration of cones, whatever the expression pattern of the mutated gene . RP is tNxnl1) . RdCVF iNxnl1)   . This inNxnl1) . MitochoNxnl1) . For reaNxnl1) . The conNxnl1) . GlucoseNxnl1) . The inhNxnl1) . This pr by rods . Since R by rods , RdCVFL  by rods . The proms of RP .Nxnl1 gene is composed of two coding exons  during evolution. Among the five introns of the NXNLa and NXNLb genes only intron four is retained, producing RdCVF-like proteins. Introns four have no sequence divergences with the non-retained introns so the genetic mechanism used by Hydra vulgaris to produce RdCVF is another yet unresolved mystery. The take home message is that RdCVF signaling predate the appearance of the eye during evolution  photoreceptors. Those are quite distinct of ciliated photoreceptors, both in terms of morphology and phototransduction. We have reported, as others, that genomes of insects, such as Drosophila melanogaster does not contain any NXNL genes  and rhabdomeric photoreceptors further downstream of its body axis  . We idenwo exons . One of llop eye . This obe uptake . We conse uptake . BSG2 pae uptake  , as what we reported for the mouse (Nxnl2−/− mice (In the retina, we have shown that  RdCVF2L . In addipostrema . In the pocampus . The dup genomes . NXNL1 ah retina . Zebrafihe mouse . Vision he mouse . Later, he mouse . In the he mouse . In agrehe mouse , in the −/− mice . TAU aggOur analysis of the emergence of RdCVF signaling stands on common ancestry and of descent with modifications, the foundation of evolutionary theory and also on punctuated equilibrium, a model of evolution with extended periods of evolutionary stasis are punctuated by rapid transitions between states . But sinHydra vulgaris, a necessary step in the understanding of the original role of this signaling prior to the appearance of the eye during evolution. We will also search for molecular clues that can validate the hypothetic metabolic advantage of rods over cones in the vertebrate retina.We plan to identify the cell surface receptor of RdCVFa in NXNL genes demonstrates that the function of the truncated thioredoxin-like protein RdCVF, whatever strange this protein is for structural biology, was conserved and recruited during evolution to function in other intercellular communications outside the eye (Our phylogenetic analysis of the  the eye . We beli


The low fertility level has become a serious social problem in China. Previous research has argued the significant influence of media use and social trust on fertility intentions, but the interaction between the two variables and how they influence fertility intentions remain further investigation. This study explored the influence mechanism of media use on Chinese women's fertility intentions from the perspective of social trust.This study collected data from the 2017 China General Social Survey, investigated the relationships between variables through bivariate correlation coefficients, and explored the differences in fertility intentions among women of reproductive age (20–49). Also, this paper examined the influence of media use and social trust by regression analysis and tested the mediating role of social trust between media use and fertility intentions with Bootstrap sampling.p < 0.01) in fertility intentions. New media use negatively influences women's fertility intentions, while traditional media use has no significant influence on women's fertility intentions. Social trust significantly influenced women's fertility intentions and partially mediated the impact of new media use on fertility intentions.Women with different media use preferences, education levels, and family incomes have significant differences (Online communication influences fertility intentions among Chinese women of reproductive age. It tends to influence their social trust by amplifying negative social news, affecting their fertility intentions further. This paper suggests the importance of strengthening social trust and online agenda-setting to improve women's fertility intentions that strategic information communication can change their perceptions of social trust. Fertility is the driving force behind human development, and low fertility has become an important global issue, impacting the global society, economy, finance, and national security . The ferStudies have examined that media information is an important factor influencing fertility intentions. In addition to providing fertility-related health knowledge and policy propaganda to the public , 14, theSocial trust refers to an individual's belief about the general trustworthiness of others, and it is a part of an individual's worldview . Social Within the traditional Chinese culture, women were disadvantaged in their fertility choices, and childbirth is always necessary for common myths . Due to On this basis, this study collected data from the 2017 Chinese General Social Survey (CGSS 2017), targeting women aged 20 to 49, to explore the influence of media use on fertility intentions among Chinese women and the role of social trust in the relationship between the two variables. Compared to previous research, the main contributions of this study are: (1) Scholars have explored the factors influencing women's fertility intentions from a socio-economic perspective. This study examined the influence of media on women's fertility intentions from the perspective of the mediated society. (2) Few studies based on the media perspective focused on Internet use, neglecting that the media environment is constructed with traditional and new media. The 'media use' in this study contains traditional media use, enhancing the understanding of the influence of diverse media types on women's fertility intentions. (3) Liu's research  selectedAs a part of fertility decisions, fertility intention is a key indicator of measuring fertility . FertiliThe factors influencing women's fertility intentions are mainly related to the macro socio-economic and micro individual characteristics . In ChinCombined with the relevant variables from the previous studies and the CGSS, this study determined education levels, family income, housing situation, and social status as control variables.In addition to traditional social, family, and individual factors, media as an important part of the social system has driven researchers' attention to exploring its impact on women's fertility. In terms of traditional media use, an Indian study showed that the official monopoly media, DoorDarshan India, significantly reduced women's fertility intentions through strong discussion about family planning and contraceptive use . In IndoIn this regard, we proposed the following hypotheses:H1: Media use negatively correlates with fertility intentions among Chinese women.H1-1: Chinese women of reproductive age have lower fertility intentions when having more frequent traditional use.H1-2: Chinese women of reproductive age have lower fertility intentions when having more frequent new media use.Studies on the impact of media use on women's fertility intentions found that media act in conjunction with other variables to influence fertility intentions. An experimental study from the United States indicated that media increased the willingness of non-student, unmarried, childless women to have children by reinforcing the portrayal of women's social roles . Liu et Empirical research found that trust affects attitudes , 47 and Early research on mass media and social trust suggested that mass media use has a certain impact on social trust. For example, a study with 1996 United States elections data indicated that the use of newspapers and television affects social trust . AnotherExisting research has proved the influence of media use and social trust on fertility intentions and the impact of media use on social trust. However, the exact influence mechanisms are undetermined. Whether social trust plays a role in media use influencing fertility intentions needs further exploration. This study proposed the following hypotheses  any property currently?”; social status refers to the question “In general, which social level are you at?”, ranging from 1 (the lowest level) to 10 (the highest level). This study coded the relevant variables to ensure statistical consistency: education levels (without education = 0 to postgraduate and above = 6), housing situation , family income was measured into different household income levels based on the average annual household income ; social status was divided into three groups .p < 0.01) in fertility intentions. However, there are no significant differences in fertility intentions between reproductive-aged women with different housing situations, social status, and social trust.p < 0.05) and social trust (p < 0.05) are positively correlated with fertility intentions. Combined with the ANOVA results, women with higher social trust have the most significant fertility intentions (M = 1.87 ± 0.72). Education levels (p < 0.01), family income (p < 0.01), new media use (p < 0.01) are negatively correlated with fertility intentions. The results show that groups with high education level (M = 1.75 ± 0.74), high annual family income (M = 1.77 ± 0.74), and new media preference (M = 1.82 ± 0.75) have lower fertility intentions.p < 0.05), and social trust positively affect fertility intentions . Regarding the correlation between traditional media use and fertility intentions is not significant, Hypothesis 1 is partially supported. In detail, H1-1 is not supported, and H1-2 is supported. Besides, H2-2 is also supported.This study conducted a hierarchical multiple regression analysis to investigate further the factors influencing women's fertility intentions. First, we used education levels, housing situation, social status, and annual family income as control variables for regression analysis with fertility intentions, forming Model 1. Then, we added media  use and social trust based on the control variables to regress with fertility intentions, forming Model 2. As shown in p < 0.01), while traditional media use is not significantly correlated with social trust. Thus, H2-1 is partially supported.This study used social trust as the mediating variable to further investigate the influence of media use and social trust on women's fertility intentions, exploring the possible influencing mechanism. This study employed the hierarchical regression analysis to test the mediating effect. First, we took education levels, housing situation, social status, and annual family income as the control variables and added media use  on this basis to regress with fertility intentions, forming Model 3. Then, we added media  use based on the four control variables to regress with social trust, forming Model 4. Model 2 seen as , Model 32 is a descriptive variable in most situations but not a test variable  for a*b includes 0. In that case, the mediating effect is insignificant .The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Hedgehog (HH) signaling is an intercellular communication pathway involved in directing the development and homeostasis of metazoans. HH signaling depends on lipids that covalently modify HH proteins and participate in signal transduction downstream. In many animals, the HH pathway requires the primary cilium, an organelle with a specialized protein and lipid composition. Here, we review the intimate connection between HH signaling and lipids. We highlight how lipids in the primary cilium can create a specialized microenvironment to facilitate signaling, and how HH and components of the HH signal transduction pathway use lipids to communicate between cells. Drosophila genetic screen for developmental regulators  and the G protein-coupled receptor GPR161 localize to the ciliary membrane . BindingOne theoretical evolutionary advantage of scaffolding signal transduction within the primary cilium is that it may increase signaling fidelity by imposing an additional level of regulation through subcellular trafficking. Although the primary cilium shares a membrane that is contiguous with the plasma membrane, the cilium can signal distinctly from the rest of the cell . Key to Over the last decade, we have gained some understanding of how the protein composition of the cilium is controlled. For example, a region near the base of the cilium called the transition zone, recognized electron micrographically by prominent structures called Y-fibers connecting the axoneme to the ciliary membrane, controls protein accumulation within the cilium .The distinct protein composition of the ciliary membrane raises the interesting question of whether the lipid composition of the ciliary membrane similarly differs from that of other cellular membranes. Less is understood about how different lipids are distributed throughout the cell, including at the cilium.Broadly speaking, lipids play three biological functions: as energy storage, as the principal components of cellular membranes, and as participants in signal transduction. Lipid droplets store neutral lipids that can be catabolized to generate ATP. Cellular membranes are primarily composed of bilayers of amphipathic phospholipids. Other lipids, such as sterols and phosphoinositides, are non-uniformly distributed and define distinct cellular membranes. Subcellular differences in lipid composition affect membrane curvature, tension, and the function of signaling proteins .One intercellular communication pathway dependent on lipids is HH signaling. For example, lipidation of HH ligands is key to their activity and extracellular distribution as gradients to pattern developing tissues . DownstrParamecia and Tetrahymena are enriched in phosphonolipids (consisting of the well-named ciliatine attached to a lipid backbone) and sphingolipids P and the plasma membrane relatively enriched in PIP2 . An addiary base  (Dyson eary base .2 into PI(4)P and localize to primary cilium  convert PIPy cilium , 2013. Ty cilium .2 within the ciliary membrane is critical for HH signal transduction P2 to control the delivery of a negative regulator of HH signaling, GPR161, to cilia. In the absence of INPP5E and ciliary PI(4)P, TULP3 and GPR161 mis-accumulate in cilia (Maintenance of elevated PI(4)P and depleted PIPsduction . Loss ofin cilia . GPR161 in cilia . We recein cilia . Thus, mAside from affecting GPCR localization, ciliary phosphoinositides may also directly affect GPCR function. Phosphoinositides can stabilize GPCR active states or enhance specific G-protein coupling . DiffereSterol lipids are a diverse class of lipids synthesized by the mevalonate pathway. Both cholesterol, the predominant sterol in vertebrate cells, and select oxysterols can bind to SMO to activate the HH pathway . As SMO Unlike the case with phosphoinositides, there is not clear evidence of enriched localization of sterol or oxysterol catabolic enzymes at the cilium itself. However, a recent study identified sterol biosynthetic enzymes that localize at the ciliary base, including DHCR7 . DHCR7 iDrosophila, which we discuss in two broad categories: signaling activity and signal distribution.Not only are lipids critical for creating specialized sub-cellular compartments that facilitate signaling, but lipids participate with certain core components of the HH pathway in ways critical for signaling. For example, HH proteins are covalently linked to palmitoyl and cholesterol . InitialDrosophila HH and vertebrate SHH are differentially dependent on palmitoylation. In mouse fibroblast cells, non-palmitoylated SHH can still signal, albeit at reduced strength , of which most vertebrates have two homologs, PTCH1 and PTCH2 . PTCH prThese structural similarities suggest that PTCH1 functions similarly to NPC1, validated by several cryo-EM-elucidated structures of the core of PTCH1 . Indeed,Numerous PTCH1 mutations associated with the human birth defect holoprosencephaly increase its ability to inhibit SMO . Loss-ofCaenorhabditis elegans, have lost the HH pathway but retained PTCH homologs. One of these, PTR-18 clears a secreted protein, GRL-7, distantly related to HH  functions not in HH reception but in transmitting HH from the cells in which it is produced . DISP1 fMany of the residues involved in coordinating sodium are also present in PTCH1, consistent with evidence that a sodium or potassium gradient is critical to the ability of PTCH1 to suppress the signaling activity of SMO . It willIn addition to PTCH, HH is bound by additional proteins not essential for all HH communication, including HHIP, CDON, BOC, GAS1 and LDL receptor-related protein 2 (LRP2) . These aLRP2 in humans cause Donnai-Barrow syndrome, which includes craniofacial defects that may be related to altered HH signaling  receptors. LRP2 is required, like SHH, for forebrain development in mice . Inheritignaling , 2008.Some other LRP family members also function in developmental pathways. For example, LRP5 and LRP6 are part of the WNT receptor complex . WNT ligWhere do ciliary lipids come from? In animals, cholesterol is generated within the cytosol and endoplasmic reticulum (ER) or delivered via LDLs. Upon uptake, LDL is endocytosed and fused with lysosomes to release cholesterol for delivery to the plasma membrane . A key rTrichoplax, sea anemones and sponges, encode members of the LRP family member , suggesting that LRP proteins arose before porifera and placozoa split from each other early in the evolution of multicellular animals. Thus, it is possible that evolution acted on a system for lipid nutrient uptake, converting it into systems for cell-cell communication such as WNT and HH signaling.The endocytosis of a variety of lipid-associated proteins via LRP family members raises the possibility that internalization of extracellular lipids was the original role for these proteins. Although speculative, it is possible to imagine that extracytosolic lipid-binding proteins, functionally akin to the evolutionarily ancient tubular lipid-binding proteins (TULIPs) or the more recently evolved cholesterol carrier NPC2, might have facilitated lipid uptake . PerhapsChlamydomonas possesses two PTCH orthologs (Cre02.g093500 and Cre12.g496350) which, unfortunately, have not been studied.Like LRP proteins, a canonical HH pathway is present in many basal animals, including sponges and sea anemones, but is absent from choanoflagellates and other single-celled eukaryotes . DespiteChlamydomonas membranes is not cholesterol, but ergosterol , an extracellular linker domain, a transmembrane heptahelical bundle (HHB), and a C-terminal cytosolic tail.How might PTCH inhibit SMO activity? Previous hypotheses posited that PTCH directly binds to and sequesters SMO in a way that is relieved upon HH binding to PTCH . HoweverLike PTCH, SMO binds sterols at several sites  Myers e. SMO mutHow sterols activate SMO binding remains unclear. Although unprecedented for a GPCR-like protein, one possibility is that these binding sites form a continuous intramolecular channel through SMO capable of sterol transport  Huang e. Mutatioin vivo.In addition to interacting with sterols, SMO can be covalently modified by cholesterol at the CRD . This chThe cholesterylation of SMO is inhibited by PTCH1 and promoted by HH ligand . Understin vivo. Indeed, the SMO-activating sterol may be cholesterol, oxysterol, or some combination thereof. Given that cholesterol is a highly abundant lipid in the plasma membranes of animal cells and quickly transits between the inner and outer leaflets, it is unclear how PTCH1 could inhibit cholesterol accumulation specifically in the outer leaflet to prevent SMO misactivation. One possibility is that much of the membrane-associated cholesterol is sequestered as a form that cannot regulate SMO ,25-EC] are enriched in the primary cilium, can bind to SMO, and can promote the accumulation of SMO in cilia, and thus are candidate regulators of SMO activation . As SMO In this review, we have summarized the intimate connection between HH signaling and lipids. Lipids participate in the HH-mediated orchestration of developmental and homeostatic processes at multiple levels, including as constituents of cellular membranes, as ligands or substrates for key pathway components, and as covalent modifiers of HH and SMO.Chlamydomonas, Tetrahymena and Paramecia. In vertebrates, primary cilia also have a unique lipid composition, including enrichment in PI(4)P. Vertebrate HH signal transduction depends on primary cilia, and on the lipids of the primary cilium, bringing a subcellular focus to many steps of HH signal transduction.Cilia are evolutionarily ancient organelles which possess a distinct ciliary lipid composition in organisms as diverse as Despite remarkable advances, our understanding of the role and regulation of lipids trails our understanding of proteins. The development of new tools to detect and perturb specific lipids will diminish this gap. For example, specific and sensitive lipid biosensors will permit visualization of the spatial distribution of the ciliary lipid composition. To help unravel how lipids function in HH signaling, it will be particularly helpful to develop sterol biosensors, refine mass spectrometry-based lipidomic approaches, and create optogenetic or chemogenetic approaches to specifically deplete lipids in subcellular domains such as the primary cilium. Especially in the emerging era of superresolution microscopy, identification of lipid domains and how they are dynamically regulated may be in the offing. As we have some understanding of how HH signals remodel ciliary protein composition, it will be particularly interesting to assess whether HH signals also dynamically remodel the ciliary lipid composition to activate signaling.


It was the first human retrovirus ever associated with a human cancer. Although most HTLV-1-infected individuals remain asymptomatic for life, a subpopulation develops ATL or HAM/TSP. Although the factors that cause these different manifestations of HTLV-1 infection are not fully understood, accumulating evidence suggests that the complex virus-host interactions, as well as the host immune response against HTLV-1 infection, appear to regulate the development of HTLV-1-associated diseases. This review outlines and discusses the current understanding, ongoing developments, and future perspectives of HTLV-1 research.Human T-cell leukemia virus type 1 (HTLV-1) is a replication-competent human retrovirus associated with two distinct types of diseases: a malignancy of mature CD4 Human T-cell leukemia virus type 1 (HTLV-1) belongs to the genus Deltaretrovirus of the Orthoretrovirinae subfamily and infects approximately 5–10 million individuals worldwide . HTLV-1 Since the discovery of HTLV-1 and its association with these diseases in the 1980s –7, signiHTLV-1 is a latent virus. The host immune system is unable to clear the virus; therefore, HTLV-1 persists in the host and poses a lifelong threat of ATL, HAM/TSP, and other inflammatory disorders . The mecvia infected lymphocytes from HTLV-1 carriers; breastfeeding and sexual contact are common routes of transmission where infectious lymphocytes are transferred to a new host  that are specific for viral antigens , 24, 25.de novo infection. Each infected cell carrying a single copy of the HTLV-1 provirus in the genome gives rise to a group of sister cells, or a clone, by mitotic division, which shares the same proviral integration site. Gillet et al. estimated the abundance of each clone, or clonality, in ACs and patients with ATL and HAM/TSP by quantifying the frequency of each provirus integration site using high-throughput sequencing , cAMP response element-binding protein (CREB), and activator protein 1 (AP-1) for plus-strand transcription. In contrast, minus-strand transcription is driven from U5 in the 3′ LTR by transcription factor Sp1 . HTLV-1 HTLV-1 tax and HBZ have been extensively studied to understand the pathogenicity of HTLV-1  Figure . Tax binDespite the pleiotropic functions of HTLV-1 plus-strand gene tax, tax mRNA is often not detected in clinically isolated PBMCs , 49. ThiHTLV-1 proviruses are often defective in ATL. Tamiya et al. reported two types of defective proviruses: lacking the retroviral gag and pol segments or lacking the 5′ LTR . In someThe second mechanism of gene silencing involves point mutation in the tax gene. A point mutation that introduces a premature termination codon in the tax mRNA results in the loss of functional Tax protein, a strong activator of its viral sense promoter , 54.The third mechanism involves epigenetic modification. The cytosine residues in the 5′ LTR and the adjacent downstream region are highly methylated; although the 3′ LTR has a sequence identical to the 5′ LTR, the 3′ LTR is not methylated , 56. Curin vivo is reversible. HTLV-1-positive PBMCs from HTLV-1-infected individuals initiate viral gene expression once they are isolated from the peripheral blood and cultured  to detect viral transcripts in HTLV-1-infected cells in vitro . These findings suggest that Tax is essential to initiate transformation, while HBZ has roles in promoting viral replication and cellular proliferation to maintain the transformed ATL cells when Tax expression is extinguished. If this is the case, it may be the most efficient method to escape HTLV-1-specific CTLs.Approximately 60% of ATL patients do not express tax mRNA in freshly isolated PBMCs . Tax is Previous reports have described the downregulation of microRNAs in ATL cells , 77. ThiIn patients with HAM/TSP, the quantity of PVL in PBMCs is significantly higher than that in ACs and is well correlated with the concentration of neopterin in the cerebrospinal fluid (CSF) , a markein vivo but is expressed persistently or at frequent intervals in infected individuals (in vivo.HTLV-1-specific CTLs are abundant in PBMCs of infected individuals, and their frequency is proportional to the PVL, indicating that HTLV-1 is not latent ividuals . Interesividuals , 84, PVLividuals , 86. ThiIn recent decades, it has become evident that chronic inflammation and tumor development are closely related . Infectiin vitro (There is strong evidence suggesting that inflammation, induced by HBZ, promotes the development of ATL. HBZ-transgenic mice develop lymphoma, in which it was shown that HBZ induces Foxp3 expression and the proliferation of the regulatory T-cell phenotype . Howeverin vitro . Higuchiin vivo. Increasing evidence suggests that both HBZ and Tax play distinct but important roles during very long latency periods in disease induction. Characterization of the viral gene expression profile throughout the infection process is essential to provide key functional information to shed light on HTLV-1 pathogenesis. As ATL is still dismal and HAM/TSP remains an intractable disease, the establishment of a precise understanding of disease developmental pathways is an urgent requirement. Further studies using newly developed methods with large amounts of data, such as computational biology and bioinformatics, are warranted to provide in vivo evidence for these points.HTLV-1 induces T-cell leukemia/lymphoma and systemic inflammation MM, TN, and MS analyzed past literature and wrote the manuscript. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Brain-derived neurotrophic factor (BDNF) signaling through its receptor TrkB has for a long time been recognized as a critical mediator of the antidepressant drug action, but BDNF signaling has been considered to be activated indirectly through the action of typical and rapid-acting antidepressants through monoamine transporters and glutamate NMDA receptors, respectively. However, recent findings demonstrate that both typical and the fast-acting antidepressants directly bind to TrkB and thereby allosterically potentiate BDNF signaling, suggesting that TrkB is the direct target for antidepressant drugs. Increased TrkB signaling particularly in the parvalbumin-expressing interneurons orchestrates iPlasticity, a state of juvenile-like enhanced plasticity in the adult brain. iPlasticity sensitizes neuronal networks to environmental influences, enabling rewiring of networks miswired by adverse experiences. These findings have dramatically changed the position of TrkB in the antidepressant effects and they propose a new end-to-end model of the antidepressant drug action. This model emphasizes the enabling role of antidepressant treatment and the active participation of the patient in the process of recovery from mood disorders. Soon after its discovery, it was recognized that the synthesis of brain-derived neurotrophic factor (BDNF) is regulated by neuronal activity . This fiAnother line of research that led to the recognition of the role of BDNF and TrkB in the mechanisms of antidepressant drug action is related to neuronal plasticity. It has been known for decades that the clinical effects of antidepressants appear after a delay of several weeks, although the biochemical effects of these drugs take place within minutes or hours. One potential explanation for this delay was that some kind of physical, time-consuming event might be required for the clinical effect to appear, and neuronal plasticity that involves physical growth and pruning was a natural candidate . As BDNFThe finding that antidepressant treatments promote the proliferation and survival of newly-born neurons in the rodent hippocampal dentate gyrus further supported a role of long-lasting plastic changes in the antidepressant action . HoweverEssentially all antidepressant treatments tested so far have proven to increase the expression of BDNF mRNA and in most cases also BDNF protein levels. These treatments include typical antidepressants, including classical tricyclic, monoamine oxidase inhibitors, and serotonin-selective antidepressants (SSRI) , 2011, tAntidepressants also promote BDNF release and signaling through TrkB . ConsistThe expression of BDNF mRNA and protein have also been investigated in humans with depression and antidepressant treatment. BDNF mRNA and/or protein levels have been reported to be reduced in postmortem brain samples of depressed patients  and suicIt has been widely considered that the effects of antidepressants on BDNF and TrkB signaling are indirect, mediated by the action of typical and fast-acting antidepressants on serotonin and NMDA-type glutamate receptors, respectively. However, recent findings have questioned the indirect action of antidepressants on BDNF and neuronal plasticity and revealed a direct binding of these drugs to TrkB .in vitro and in vivo. It is important to note that such heterozygous mutation does not reduce BDNF binding to TrkB and heterozygous mice with this mutation do not show any behavioral phenotype -containing interneurons are critical in this regard. PV neurons have already been implicated in neuronal plasticity: their maturation coincides with the closure of critical periods of early life plasticity and inhibition mediated by PV neurons is reduced during iPlasticity induced by antidepressants or other treatments in the adult brain . We founAntidepressants influence TrkB activity in PV neurons also through other mechanisms. We recently found that antidepressants disrupt the interaction between TrkB and the protein tyrosine phosphatase sigma (PTPσ) . PTPσ inWe have further found that antidepressant treatment also disrupts the interaction between TrkB and the adaptor protein complex-2 (AP-2) that is a critical mediator of endocytosis . ConsequTaken together, our recent findings show that antidepressants facilitate the ability of BDNF to activate TrkB receptors in PV interneurons through several distinct mechanisms: by directly binding to TrkB and allosterically increasing BDNF signaling ; by inhiPrevious studies have already established the critical role for BDNF-TrkB signaling in the antidepressant action , but TrkIn the updated network model of depression, the initial event is binding of an antidepressant molecule to TrkB . The finOne of the most unexpected aspects of the model of the critical role of TrkB binding in the antidepressant action is that a common binding site would mediate the effects of both fast and slow-acting antidepressants. It should be noted, however, that many different antidepressants reach higher than micromolar brain concentrations at the steady state, which is compatible with binding to TrkB . Intriguper se, but by enhancing plasticity promote the action of the particular network, which may ameliorate but also aggravate depression (The action of antidepressants on network function helps to explain some discrepancies found in the behavioral responses to antidepressants. While administration of BDNF and TrkB agonists produce antidepressant-like effects on the cortex and hippocampus ,b, TrkB pression .The updated network hypothesis of antidepressant action is in many aspects very different from the traditional monoamine hypothesis. Although there is some evidence to suggest that BDNF signaling might be compromised in depression , this moAll authors listed have made a substantial, direct, and intellectual contribution to the work, and approved it for publication.


The incidence of hyperuricemia (HUA) and gout continuously increases and has become a major public health problem. The gut microbiota, which colonizes the human intestine, has a mutually beneficial and symbiotic relationship with the host and plays a vital role in the host’s metabolism and immune regulation. Structural changes or imbalance in the gut microbiota could cause metabolic disorders and participate in the synthesis of purine-metabolizing enzymes and the release of inflammatory cytokines, which is closely related to the occurrence and development of the metabolic immune disease HUA and gout. The gut microbiota as an entry point to explore the pathogenesis of HUA and gout has become a new research hotspot. This review summarizes the characteristics of the gut microbiota in patients with HUA and gout. Meanwhile, the influence of different dietary structures on the gut microbiota, the effect of the gut microbiota on purine and uric acid metabolism, and the internal relationship between the gut microbiota and metabolic endotoxemia/inflammatory factors are explored. Moreover, the intervention effects of probiotics, prebiotics, and fecal microbial transplantation on HUA and gout are also systematically reviewed to provide a gut flora solution for the prevention and treatment of related diseases. Uric acid (UA) is the terminal metabolite of human purine compounds, and excessive UA production and/or reduced UA excretion can lead to hyperuricemia  . Gout isVarious microorganisms colonize the human gut and play an irreplaceable role in regulating human energy and metabolism. Structural changes or imbalances in the gut microbiota may cause organism metabolic disorders . ConsideThere are many types of microorganisms in the human intestinal tract. The gut microbiota is composed of three different types of bacteria, namely, beneficial, harmful, and opportunistic pathogenic bacteria; among these, Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria are the most important components of the human gut microbiota . In receCoprococcus than the normal controls   . The F/Bio (P/B) . An incrPrevotella, Fusobacterium, and Bacteroides were increased in gout patients, while the relative abundances of Enterobacteriaceae and butyrate-producing species were decreased -producing bacteria Blautia and Roseburia were significantly decreased  were enriched in HUA rats induced by a high-fat diet containing 10% yeast extract, but 10 other genera  were less abundant  was significantly increased in an oxonic acid diet-induced HUA rat model, supplementation with probiotics could reduce this expression, and significant differences in the microbiota were observed between the treated and untreated fecal samples . Enterocgoslings . A high-teroides . ImplemeLactobacillus gasseri PA-3 in the intestine can absorb and utilize purine, thereby reducing the intestinal absorption of purine in the diet and reducing the serum UA levels  activity (E. coli (STEC) and enteropathogenic E. coli (EPEC) can promote the release of XOD in intestinal epithelial cells, accelerate the decomposition of hypoxanthine and xanthine, and convert more purines for UA  inflammasome is involved in the development of gout as a sensor of metabolic stress . In addiammasome . Enterocroptosis . Lactobaof NLRP3 . Bifidobammasome . Bacteroammation . CurrentLactobacillus, Bifidobacterium, and Saccharomyces have a long history of safe and effective use as probiotics  is a TCM formulation used clinically for the treatment of gout and HUA. An analysis of CoTOL targeted bacteria in a mouse model of obesity HUA inoculated with the XDH-producing bacterium Streptococcus faecalis. The results showed that the S. faecalis inoculation resulted in elevated UA and altered the gut microbiota structure, while the CoTOL treatment increased the abundance of Akkermansia and decreased the abundance of Bacteroides and Alloprevotella (Cichorium intybus L.)  and reducing pathogenic flora (Helicobacteraceae)  have a long history in the treatment of gout and have the advantages of multichannel, multitarget, and multilevel symptomatic treatment. TCMs exert therapeutic effects by lowering UA, exerting anti-inflammatory, antioxidation effects, and protecting the kidneys. CoTOL (consisting of votella . In goutvotella . In addivotella . By reduybus L.) . In addieraceae) . Furthereraceae) . The guteraceae) . In parteraceae) . StudyinUlva lactuca (ULP) exerts a UA-lowering effect by regulating the gut microbiota, which is characterized by increasing the abundance of beneficial microorganisms while reducing the abundance of harmful bacteria to restore the homeostasis of the gut microbiota (Enteromorpha prolifera (EPP) significantly reduced serum UA, BUN, serum XOD, and hepatic XOD in HUA mice. In addition, EPP maintained the stability of the gut microbiota, confirming that Parasutterella is closely related to the regulation of HUA  derived from the gut microbiota in Uox-knockout mice  can significantly alleviate HUA, regulate UA metabolism, inhibit the activation of NLRP3 inflammasome and NF-kB-related signaling pathways, and restore the m6A methylation levels  attenuates HUA and renal inflammatory phenotypes, reprograms uric acid metabolic pathways, inhibits the activation of NLRP3 inflammasome and TLR4/MyD88/NF-κB signaling pathway, and inhibits p65-NF-κB phosphorylation . Furthern levels . Furthern levels , suggestn levels , therebyn levels .In HUA-induced chronic kidney disease (CKD), the flavonoid component fisetin improves renal function, renal fibrosis, and intestinal dysbiosis . The alkFMT is a treatment method that transplants the intestinal microbiota of healthy hosts into patients through the digestive tract to restore the diversity of intestinal microbes. It is a current clinical research hotspot. The serum UA concentration is closely related to the balance of the intestinal microecology. Using fecal microbial transplantation to maintain intestinal microecology in patients with HUA and gout may be a new treatment method. Washing microbiota transplantation reduces the serum UA levels in gout patients, is associated with a reduction in the frequency and duration of acute gout flares, reduces the diamine oxidase and endotoxin levels, and helps improve their damaged gut barrier function . The antIntestinal dysbiosis in patients with gout mainly manifests as an increase in opportunistic pathogens and a decrease in bacteria that promote the production of anti-inflammatory cytokines. The gut microbiota is involved in the metabolism of purines and UA. An imbalance in the gut microbiota could increase the concentration of UA, and the long-term deposition of UA in the joints can cause gout. Intestinal dysbiosis may lead to the occurrence and development of gout by inducing the body to produce endotoxin, triggering chronic inflammation, or altering the metabolism of SCFAs. Thus far, some progress has been achieved in research investigating the relationship between the gut microbiota and HUA and gout , which nin vitro, in vivo, and in clinical trials need to be gradually verified before widespread application. The complexity of the gut microbiota, the lack of evidence-based medicine for new treatment methods, and the lack of clinical data all require further exploration in future research.In the prevention and treatment of HUA and gout, maintaining intestinal microecological balance plays an important role in the regulation of UA, which may provide new hope for the treatment of gout patients. At present, through microecological therapy, such as probiotics, prebiotics, and fecal microbial transplantation, adjusting the intestinal microecological balance to prevent HUA and gout is a clinical research hotspot. At the same time, however, many questions remain to be resolved. On the one hand, it is easy to breed other microorganisms during the microbial culture. Therefore, it is very important to ensure the safety of microorganisms and prevent contamination by miscellaneous bacteria. In addition, there are differences in UA and purine metabolism between humans and experimental animals. Therefore, more clinical trials are needed to elucidate the mechanism of gut microbiota in HUA and gout patients. Another problem is that a patient’s condition needs to be considered, and an accurate diagnosis and proper examination are necessary. The use of gut microbiota in HUA and gout treatment is still in its infancy, and its efficacy and safety Currently, research investigating the mechanism of gut microecology leading to gout mainly focuses on biochemical aspects, such as UA metabolism and the release of inflammatory factors. High levels of UA and joint pain are caused by problems with the body’s immune response . TherefoConceptualization, ZW, JT; methodology, YL, JH, YL; software, WL, ZL; validation, ZW, JT; investigation, XX, YL; resources, ZB; data curation, WL; writing—original draft preparation, ZW; writing—revised manuscript, ZW, YL, WL; writing—review and editing, JT and JH; visualization, ZB; supervision, XX; project administration, ZW; funding acquisition, ZW and JT All authors have read and agreed to the published version of the manuscript.This work has been supported by Macao Science and Technology Development Fund (SKL-QRCM(UM)), Key R&D project of Sichuan Province (2022YFG0145), “Xinglin Scholar” Scientific Research Promotion Plan of Chengdu University of Traditional Chinese Medicine (BSH2021017).The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Insulin and IGF-1 receptors (IR and IGF1R) are highly homologous and share similar signaling systems, but each has a unique physiological role, with IR primarily regulating metabolic homeostasis and IGF1R regulating mitogenic control and growth. Here, we show that replacement of a single amino acid at position 973, just distal to the NPEY motif in the intracellular juxtamembrane region, from leucine, which is highly conserved in IRs, to phenylalanine, the highly conserved homologous residue in IGF1Rs, resulted in decreased IRS-1/PI3K/Akt/mTORC1 signaling and increased Shc/Gab1/MAPK cell cycle signaling. As a result, cells expressing L973F-IR exhibited decreased insulin-induced glucose uptake, increased cell growth, and impaired receptor internalization. Mice with knockin of the L973F-IR showed similar alterations in signaling in vivo, and this led to decreased insulin sensitivity, a modest increase in growth, and decreased weight gain when mice were challenged with a high-fat diet. Thus, leucine-973 in the juxtamembrane region of the IR acts as a crucial residue differentiating IR signaling from IGF1R signaling.  Insulin and IGF-1 mediate their pleiotropic biological effects by binding to insulin and IGF-1 receptors (IR and IGF1R) on the surface of the cell . Due to Recently, using chimeric receptors, we have demonstrated how domain differences between IR and IGF1R contribute to the distinct functions of these receptors . Thus, rINSR L973F substitution. Here, we show that substitution of phenylalanine for leucine at position 973 in the IR decreases IRS-1/PI3K/Akt/mTORC1 signaling, upregulates Shc/Gab1/MAPK signaling and cell cycle–related pathways, and decreases ligand-stimulated receptor internalization in vitro. Functionally, this leads to decreased insulin-induced glycolysis and an increased proliferation rate at the cellular level. Mice with knockin of the L973F-IR show similar signaling alterations, which lead to impaired insulin sensitivity, increases in growth, and resistance to weight gain upon a high-fat diet (HFD) challenge. Thus, leucine-973 in the +1 position following the NPEY motif in the juxtamembrane region is a key residue differentiating IR signaling from IGF1R signaling.By sequential substitution of all amino acids that differ in the juxtamembrane region of IR versus IGF1R, we have previously shown that another important sequence difference in the region surrounding the NPEY motif of IR and IGF1R may be located at position 973 just C-terminal to motif. This residue is a leucine in IR and a phenylalanine in IGF1R, and we have found that the replacement of leucine-973 in the juxtamembrane region of IR with Phe decreases IRS-1 binding and increases Shc binding. In the present study, we have explored in depth this important region of these receptors both in vitro and in vivo by generating cell lines in which we have deleted both endogenous IR and IGF1R and then reconstituted the cells with either WT human IR B isoform (WT-IR) or a mutant IR in which leucine-973 has been changed to phenylalanine (L973F-IR) as well as by creation of a knockin mouse model with an The NPEY motif in the juxtamembrane region in both IR and IGF1R is critical for recruitment of receptor substrates including IRS-1 and Shc , 17. We https://doi.org/10.1172/JCI161472DS1). To determine potential differences between WT-IR and L973F-IR in insulin signaling, we stimulated WT-IR and L973F-IR preadipocytes with 0, 0.1, 1, 10, and 100 nM insulin for 15 minutes and assessed downstream signaling. While insulin stimulation induced robust tyrosine autophosphorylation of both receptors with dose response to insulin , 49 sites were equally upregulated (category I-A) and 288 sites were equally downregulated (category II-A) in both WT-IR and L973F-IR cells in response to ligand stimulation (up- or downregulation of these sites was not significantly changed between these 2 cell lines). At the single concentration tested (100 nM), most phosphosites were regulated almost equally by both insulin and IGF-1. For example, SRSF4receptor , while Ry ligand . These omulation , D and EP < 0.05). Reactome pathway (https://reactome.org/) enrichment analysis of phosphosites upregulated more in WT-IR cells than in L973F-IR cells identified 6 pathways, including PIP3/Akt signaling and IR signaling pathways (https://www.genome.jp/kegg/pathway.html) also showed significant enrichment of proteins associated with the mTOR signaling pathway (P < 0.05). Reactome pathway analysis of these phosphosites showed enrichment of pathways associated with cell cycle, mitosis, and many SUMOylation processes . Twenty-one of these sites were downregulated by ligand stimulation to a greater extent in WT-IR cells than L973F-IR cells, including TBC1D15S201 and EIF2K4S550, which are associated with intracellular trafficking and translational control  were preferentially stimulated by WT-IR compared with L973F-IR. Similarly, many phosphosites associated with mTORC1 signaling  and several phosphosites related to PIP3-activated Akt signaling  were more highly upregulated by WT-IR than L973F-IR. On the other hand, many phosphosites on proteins associated with cell cycle and mitosis  and several phosphosites associated with MAPK signaling  were more highly upregulated by L973F-IR than WT-IR. Four phosphosites showed opposite regulation by ligand between WT-IR and L973F-IR. RICTORS1234 and RANBP2S2709 were upregulated by ligand in WT-IR cells, but downregulated by ligand in L973F-IR cells, while the converse was true for PAK4S174 and NUP153S335. Several of these changes in the phosphoproteomics were confirmed by immunoblotting using phosphosite-specific antibodies, including phosphorylation of mTORS2481 and S6S235/236, which were more highly upregulated by WT-IR than L973F-IR, while phosphorylation of c-JunS73 was more highly upregulated by L973F-IR than WT-IR , mitosis, kinesin action, and SUMOylation  was not regulated by ligand, but was significantly higher in the basal state in cells expressing WT-IR versus L973F-IR, and phosphorylation of 140 sites on 109 proteins (category III-B) was significantly higher in the basal state in L973F-IR than in WT-IR cells. The former included GRB10CCNE2S21 , A and BCCNE2S21 . This reCCNE2S21 . PathwayCCNE2S21 . On the Oylation . Thus, iP53 and P21 were not different under basal conditions between WT-IR and L973F-IR preadipocytes, they were downregulated more in L973F-IR cells than in WT-IR cells after insulin stimulation for 6 hours  and cholesterol synthesis  by insulin in WT-IR preadipocytes was severely blunted in L973F-IR preadipocytes  between male WT and L973F-IR mice, at least over the first 5 months of life . Both tyY608 and AktS473 in skeletal muscle of L973F-IR mice compared with WT control mice   . We also-IR mice . On the -IR mice , as with-IR mice , F and G-IR mice , H and I-IR mice , J and K-IR mice , L and M-IR mice , despite-IR mice . The higInsulin and IGF-1 are major regulators of metabolism and systemic growth both in vivo and in vitro . Thus, iSeveral studies have shown that the NPEY motifs in the juxtamembrane region of the IR and IGF1R have key roles in the recruitment of the immediate substrates of IR, including IRS-1/2 and Shc , 16, 17.We find that in cells, this results in a reduction in IRS-1/PI3K/Akt/mTORC1-mediated signaling with even more marked upregulation of Shc/Gab1/MAPK signaling and phosphorylation of cell cycle–related proteins. Global phosphoproteomics analysis also reveals the differences in signaling by L973F substitution, including decreased phosphorylation of proteins involved in the SUMOylation process and increased phosphorylation of proteins involved in apoptotic signaling and mRNA splicing. These signaling alterations associated with the L973F-IR result in decreased insulin-induced glycolysis and increased cell growth rate in L973F-IR cells. These data are in agreement with our recent phosphoproteomic analysis of the IR versus the IGF1R themselves . Thus, mIn addition to substrate binding, the NPEY motif in both IR and IGF1R is known to be involved in receptor internalization , 22. PreIn addition to the insulin-stimulated differences in protein phosphorylation, many phosphosites detected in the phosphoproteomics are altered under basal conditions by changing leucine at position 973 to phenylalanine. Indeed, many of the phosphosites upregulated by L973F-IR in the basal state were on proteins associated with cell cycle and mitosis. We have previously shown that, in addition to its classical signaling pathway, the unoccupied IR can exert some ligand- and tyrosine kinase–independent effects , 40. ForTo fully explore the role of the L973F mutation of the IR, we created a knockin mouse in which the normal receptor was replaced by this mutated receptor in all tissues. Previous studies have shown that enhanced IGF-1 signaling can result in increases in tissue weight and somatic growth –45. For While the L973F-IR shifts the signaling pattern from a more metabolic to a more mitogenic pattern, the effects of L973F-IR on growth in vivo were modest. This may be due to the existence of an intact IGF1R in both WT and knockin mice as well as effects from both ligands, insulin and IGF-1, which could at least partially compensate for their downstream signaling effects. Some in vivo studies have shown that blocking both insulin and IGF-1 downstream signaling by deletion of both IR and IGF1R result in obvious phenotypes, which are not obvious in single deletion of IR or IGF1R , 48. ForAltered downstream signaling by the IR with the L973F substitution is certainly in large part mediated by the decrease in IRS-1 binding/phosphorylation and increase in Shc binding/phosphorylation, as shown in this study. We have previously shown that this is based on the differences in structure of the SH domains of these two different receptor substrates . This stIn summary, we have demonstrated that a single amino acid replacement of leucine-973 in the juxtamembrane region of IR to phenylalanine, which is the equivalent residue in the IGF1R, is sufficient to lead to a decrease of IRS-1/PI3K/Akt/mTORC1 signaling and an increase of Shc/Gab1/MAPK cell cycle signaling. At the cellular level, these signaling alterations lead to decreases in insulin-induced glycolysis and increases in cell growth. Mice with knockin of the L973F-IR show similar alterations in signaling in vivo, and this leads to impaired insulin sensitivity, modest increases in growth, and decreases in weight gain on HFD. Thus, leucine-973 in the +1 position following the NPEY motif in the juxtamembrane region is a key residue differentiating IR signaling from IGF1R signaling. This study explains a big part of the differences between IR and IGF1R signaling and may provide important insights into how to modify these signaling pathways for therapy of disease.S473 , AKT pan , p-ERK1/2T202/Y204 , ERK1/2 , p-ShcY239/240 , Shc , p-Gab-1Y627 , Gab-1 , p-mTORS2481 , mTOR , p-c-JunS73 , c-Jun , p- p-S6S235/236 , S6 , p-JNKT183/Y185 , and JNK  were purchased from Cell Signaling Technology. Anti-IRβ antibody  was purchased from Santa Cruz Biotechnology Inc. Anti–p-IRS-1  antibody , anti–IRS-1 antibody , and anti-vinculin antibody (MAB3574) were purchased from MilliporeSigma. Human insulin was purchased from MilliporeSigma. Human IGF-1 was purchased from PeproTech. The human IR (B isoform) retroviral plasmid was generated previously in the lab (Antibodies against phosphorylated IRβ (p-IRβ)/IGF1Rβ , IRβ , IGF1Rβ , β-actin catalog 4970), GAPDH , p-AKT70, GAPDHIR/IGF1R DKO brown preadipocytes were obtained as previously described , 40. DKOOocyte isolation from C57BL/6 and pronucleus injections were performed at the Transgenesis Core Facility (TCF) of the Max Planck Institute (MPI) for Biology of Ageing. To prepare gRNAIR, 5 μg crRNA (GCTCACCATCACTGGCACTG) was mixed with 10 μg tracrRNA heated to 95°C for 5 minutes and then cooled down to room temperature. To exchange codon CTC of the IR encoding leucine-973 to codon TTC encoding phenylalanine-973, we performed pronucleus injections. Injection solution was prepared as follows: 20 ng/μl gRNA-IR was incubated with 20 ng/μl Cas9 protein for 15 minutes at room temperature to generate the ribonucleotide complex RNP. Subsequently, a single stranded repair template that had 100 bp homologous regions 5′ and 3′ to the modifications was added at 20 ng/μl (AAATGTCGAACAATCCATTCCTAATTTATATAGCATTTGCCTATGTCCAGAATGCCATGGGATGTTCAAGATGTTGTGTCTCTCTTCCTCCATTAGGCAGCCGGATGGGCCAATGGGGCCCCTGTATGCATCTTCAAACCCTGAGTAttTCAGTGCCAGTGATGGTGAGCATCACCTCCTTCTTTGTGGGAATCCAGAACCCAGCCCTTGGTTTTCTTTGCTATCACTGTTAAGTCAGATCTGAGGATAGGCTAGCATCACAGGG). All reagents were obtained from IDT. gRNA-mediated Cas9 double-strand break of genomic DNA between codons tyrosine-972 and leucine-973 should initiate homologous-directed repair using the ssDNA repair oligo, thereby mutating the PAM sequence, exchanging codon leucine-973 to phenylalanine-973, as well as inserting silent point mutations at codons glycine-962 and proline-963 to generate an ApaI restriction site for genotyping. Offspring were genotyped with a common PCR reaction using primers 5′-CCCTCACTTCCTCTAATTTGGACA-3′ and 5′-CACTATGTAAAGTCAAACCCAGT-3′ to result in a 658 bp fragment for both WT and L973F-IR mice. Subsequent restriction digest of PCR fragments with ApaI resulted in 141 bp and 516 bp fragments when positive for the F973 modification, whereas nonmodified WT DNA did not contain the ApaI site and thus still showed a 658 bp band upon ApaI digestion. PCR products from offspring were subcloned and Sanger sequenced and confirmed the correct codon L973F exchange in IR exon 15 as well as the ApaI site at glycine-962/proline-963. All mice were kept on a C57BL/6N background and housed at 22°C on a 12-hour-light/12-hour dark cycle with ad libitum access to water and food . HFD  was purchased from Research Diets (D-12492). For the intraperitoneal ITT, mice were fasted for 6 hours and injected with insulin at 1 U/kg/BW for male mice fed a normal diet, 0.8 U/kg/BW for female mice fed a normal diet, or 1.6 U/kg BW for male mice fed HFD. For the IPGTT, mice were fasted for 6 hours before injection of glucose at 2 g/kg/BW. For the intraperitoneal PTT, mice were fasted overnight before injection of pyruvate at 2 g/kg/BW.INSR, 5′-CGATATGGTGATGAGGAGCTGC-3′ and 5′-GTAGAAATAGGTGGGTTCCGTCCA-3′. Mouse primers used for qPCR are listed in Total RNA was isolated from cells using TRIzol reagent (Thermo Fisher Scientific). cDNA was synthesized and then quantitative PCR (qPCR) amplification was conducted with the C1000 Thermal Cycler  using iQ SYBR Green Supermix (Bio-Rad). The sequences of primers were as follows: human g for 15 minutes at 4°C and supernatants were collected. Protein concentrations were measured using the Pierce BCA Protein Assay Kit (Thermo Fisher Scientific).WT-IR and L973F-IR preadipocytes were FBS starved for 6 hours with DMEM containing 0.1% BSA, then stimulated with insulin for 15 minutes. After stimulation, cells were washed once with ice-cold PBS and collected in RIPA buffer (MilliporeSigma) supplemented with protease and phosphatase inhibitors (BioTools). Cell lysates were then centrifuged at 20,000Proteins were transferred to polyvinylidene difluoride (PVDF) membranes. Membranes were then blocked in Starting Block T20 solution (Thermo Fisher Scientific) at room temperature for 1 hour, washed 3 times with PBS with Tween-20 (PBST), and incubated with an appropriate dilution of the primary antibody  in Starting Block T20 solution overnight at 4°C. Membranes were washed with PBST and incubated with an appropriate dilution of secondary antibody in Starting Block T20 solution for 1 hour. Sheep anti-mouse HRP-conjugated antibody  was purchased from MilliporeSigma, and goat anti-rabbit HRP-conjugated antibody  was purchased from Bio-Rad. Membranes were washed with PBST, and signals were detected using chemiluminescent HRP substrates (Thermo Fisher Scientific).2 for 1 hour. Extracellular acidification rate (ECAR) values were measured in the basal state, after injection of glucose, oligomycin and 2-deoxyglucose (2-DG). The quantitative value was normalized by the respective protein content. Brown preadipocytes were differentiated, and lipid accumulation was quantified by oil red O staining as described previously  according to the protocol of the Agilent Seahorse XF Glycolysis Stress Test Kit . Brieflyeviously .2PO4, 1 mM MgSO4, 1 mM CaCl2, 120 mM NaCl, 10 mM NaHCO3, 30 mM HEPES, pH 7.4) for 20 minutes. Cells were then treated with insulin at final concentrations of 0, 1, 10, or 100 nM for 20 minutes. Glucose uptake was assessed using 2-NBDG (Thermo Fisher Scientific) at a final concentration of 100 μM for 1 hour. After incubation, cells were washed twice with PBS and the signal read using a fluorescence plate reader at excitation of approximately 465 nm and emission of approximately 540 nm. Plasma and liver cholesterol levels were measured using Total Cholesterol Assay Kits . Plasma and liver triglyceride levels were measured using the Triglyceride Colorimetric Assay Kit .Cells were FBS starved for 6 hours with DMEM containing 0.1% BSA and incubated with KRH buffer . The MS proteomics raw data and the corresponding processing reports generated in this study have been deposited in the ProteomeXchange Consortium database  via the PRIDE .HN designed research, performed experiments, analyzed the data, and wrote the manuscript. WC, BBB, and AKG helped with experiments and reviewed and edited the manuscript. FTW generated the mouse model. NJWA and MS performed phosphoproteomic analysis. HP and JMD performed bioinformatics analysis. MM supervised phosphoproteome analysis. CRK designed research, wrote the manuscript, and supervised the project.


Although the involvement of Ca2+ mobilization in mTOR signaling has been reported, the detailed molecular mechanisms by which mTOR signaling is regulated are not fully understood. The link between Ca2+ homeostasis and mTOR activation in pathological hypertrophy has heightened the importance in understanding Ca2+-regulated mTOR signaling as a key mechanism of mTOR regulation. In this review, we introduce recent findings on the molecular mechanisms of regulation of mTOR signaling by Ca2+-binding proteins, particularly calmodulin (CaM).Environmental factors are important regulators of cell growth and proliferation. Mechanistic target of rapamycin (mTOR) is a central kinase that maintains cellular homeostasis in response to a variety of extracellular and intracellular inputs. Dysregulation of mTOR signaling is associated with many diseases, including diabetes and cancer. Calcium ion (Ca It is essential for eukaryotes to sense environmental changes, such as changes in nutrients, growth factors, hormones, and stressors. This permits the organism to modulate the balance between anabolism and catabolism to regulate proper cell growth and proliferation. A key mediator in these roles is a large protein kinase called mechanistic target of rapamycin (mTOR). mTOR is a mammalian ortholog of TOR that was first identified in yeast in 1991 ,3.mTOR forms two complexes: mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). These two complexes are functionally and structurally different and have important roles in distinct intracellular signaling pathways . mTORC1 +-ATPase (v-ATPase) and solute carrier family 38 member 9 (SLC38A9) with Ragulator . The binding of Akt with PIP3 allows phosphorylation and activation by mTORC2 and 3-phosphoinositide-dependent protein kinase 1 (PDK1). Because CaM was also reported to compete with PIP3 for binding to the PH domain of Akt [3 at the plasma membrane likely promotes dissociation of CaM from Akt [2+/CaM-dependent upregulation of Akt phosphorylation occurs through changes in mTORC2 activity.Compared with the regulation of the mTORC1 pathway by CaCa2+/CaM A,B. In 1 of PI3K . Subsequ of PI3K ,110  domain . Further) domain . It is p) domain . At the n of Akt ,116, thefrom Akt   belongs to the EF-hand superfamily of Caigration ,134. Recigration . NCS1 mamotility .2+-binding domain and are directly activated by Ca2+. Fifteen isoforms of calpain have been identified in mammals [capns1 knockout mice, or upon treatment with a selective calpain inhibitor MDL28170, or by the mTOR inhibitor Torin1. Calpain-2 also contributes to brain-derived neurotrophic factor (BDNF)-induced dendritic protein synthesis, which is suggested to be an important role in memory formation [Calpains are the family of neutral cysteine proteases that possess the Ca mammals . Convent mammals ,138. Ast mammals . Indeed,2+-binding proteins other than CaM may also regulate cell proliferation and survival through the regulation of mTOR activity. Compared with the knowledge of the CaM-mediated regulation of mTOR signaling, the detailed molecular mechanisms of the non-CaM proteins remain to be clarified. Future studies on mTOR regulatory mechanisms, especially in which Ca2+-binding proteins are involved, will expand our understanding of the regulation of mTOR signaling.These observations indicate that Ca2+ signaling are fundamental pathways to regulate cellular adaptation to a wide array of environmental cues. As discussed above, novel regulatory modes of mTORC1 and mTORC2 in response to global or local changes of intracellular Ca2+ have emerged. In addition, several studies have further unveiled that Ca2+-mediated regulation of mTOR signaling is physiologically and pathologically relevant. Although our knowledge is still limited on how and when Ca2+-mediated mTOR regulation is coordinated to maintain cellular homeostasis, further molecular identification of new regulators in cooperation with Ca2+-binding proteins will greatly improve our understanding of the complex signaling network under various conditions. Although CaM antagonists are already available, it seems difficult to use those for pharmacological inhibitors of mTOR signaling due to the lack of specificity. Instead, it will be valuable to find a medicine to specifically inhibit CaM binding to target proteins, such as TSC2. In addition to drug screening, the development of a peptide with the binding motif sequence that selectively disrupts CaM–target interaction will be one of the potential clues to combat diseases associated with aberrant Ca2+ levels.Both mTOR signaling and Ca


Neurotrophins, such as nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin 3 (NT-3), NT-4, and NT-5, are proteins involved in several important functions of the central nervous system. The activation of the signaling pathways of these neurotrophins, or even by their immature form, pro-neurotrophins, starts with their recognition by cellular receptors, such as tropomyosin receptor kinase (Trk) and 75 kD NT receptors (p75NTR). The Trk receptor is considered to have a high affinity for attachment to specific neurotrophins, while the p75NTR receptor has less affinity for attachment with neurotrophins. The correct functioning of these signaling pathways contributes to proper brain development, neuronal survival, and synaptic plasticity. Unbalanced levels of neurotrophins and pro-neurotrophins have been associated with neurological disorders, illustrating the importance of these molecules in the central nervous system. Furthermore, reports have indicated that viruses can alter the normal levels of neurotrophins by interfering with their signaling pathways. This work discusses the importance of neurotrophins in the central nervous system, their signaling pathways, and how viruses can affect them. Neurotrophins (NTs), also known as neurotrophic factors, are proteins involved in many important functions in the central nervous system (CNS), such as survival, synaptic plasticity, apoptosis, differentiation, and growth ,2,3. The2+ concentration inside of TGN . A. A130]. HSV-1 is known for causing herpetic gingivostomatitis when symptomatic and can remain in a latency state in peripheral neurons and reactivate intermittently to replicate ,137. HowAnother virus belonging to the Herpesviridae is the EBV, which is known for causing Hodgkin’s disease, among other lymphomas . InteresRespiratory viruses have also been studied regarding their effects on the levels of NTs. For example, the influenza virus is a respiratory virus known for causing pathologies related to the respiratory tract . It has Interestingly, in vivo studies have demonstrated that the levels of BDNF decrease in the hippocampus of influenza virus-infected mice, regardless of whether they are neurotropic (H3N2 and H7N7) or non-neurotropic (H1N1) ,143. ThiThe hRSV is the principal respiratory virus responsible for causing infections in the lower respiratory tract in infants . It has Interestingly, it has been seen that the infection with hRSV in bronchial cells promotes the increment of NGF levels and TrkA, which is the receptor that has a high affinity for NGF, while inducing a decrease of p75NTR, which has a low affinity for NGF . Since hSARS-CoV-2 is a novel respiratory virus known for affecting the respiratory tract . It has Neurotropic viruses can interfere with the correct signaling pathway of NTs and cause neurological pathologies. However, these pathologies can persist in the long term, causing disorders such as learning and memory impairment, mood and speech disorders, and degenerative diseases .The infection with HIV can cause cognitive problems, such as HAND or HAD. However, learning and memory impairment cases are detected in HIV-positive patients that can be associated with a decrease in BDNF levels . In thesIn the case of HSV-1, few studies have been performed regarding the long-term sequels after affecting NT signaling. Interestingly, it has been reported that an increase in the number of HSV-1 viral copies can decrease the BDNF levels . TogetheRespiratory viruses can also interfere with the signaling of NTs and cause long-term sequels. Even though no specific studies associate the interference of the NTs signaling due to the infection with respiratory viruses can cause a long-term sequel, it is possible to suggest an association. For example, the influenza virus is one of the respiratory viruses known for causing long-term consequences, such as learning and memory impairment . It has Regarding hRSV and SARS-CoV-2, learning and memory impairment cause cognitive problems that have been previously described . In thisNTs are proteins involved in several essential functions of the CNS and other systems, including the immune and respiratory ,7. The aAs seen in this work, the NTs are necessary not only for the homeostasis of the CNS; therefore, more studies are needed to understand how viruses can modify their function and cause several effects in patients.


Urinary EVs carrying SLC17A3 and SLC5A8 were lower (p < 0.05) in UASFs compared with NSFs. Urinary EVs bearing SLC2A9, SLC22A12, SLC5A8, ABCG2, and ZNF365 were lower (p < 0.05) in CSFs than UASFs, while excretion of SLC17A3-bearing EVs did not differ between groups. Conclusion: EVs bearing specific UA transporters might contribute to the pathogenesis of UASD and represent non-invasive pathogenic biomarkers for calcium and UA stone risk. Background: Low urine pH and volume are established risk factors for uric acid (UA) stone disease (UASD). Renal tubular epithelial cells exposed to an acidic pH and/or UA crystals can shed extracellular vesicles (EVs) into the tubular fluid, and these EVs may be a pathogenic biomarker of UASD. Methods: Urinary EVs bearing UA transporters  were quantified in urine from UA stone formers (UASFs), calcium stone formers (CSFs), and age-/sex-matched non-stone formers (NSFs) using a standardized and published method of digital flow cytometry. Results: Urinary pH was lower ( The numbers of EVs bearing UA transporters were presented on a logp < 0.05), whereas diastolic blood pressure, estimated glomerular filtration rate (eGFR), and urine pH were significantly lower (p < 0.05) in UASFs vs. NSFs  or hypertension; serum calcium; and urine volume were all similar between groups . Body mavs. NSFs . Serum Uvs. NSFs . Only thvs. NSFs .p < 0.05), while urinary excretion of EVs carrying SLC2A9, SLC17A3, SLC22A12, ABCG2, and ZNF365 trended lower in UASFs  and risk of UA stone formation ,29,30,31Tubular fluid pH and/or uric acid concentration, both risks for UA crystallization, could potentially be altered by EVs carrying transporters. In this study, urinary EVs carrying SLC17A3 and SLC5A8 were significantly lower in UASFs compared with NSFs. Urinary EVs carrying SLC2A9, SLC22A12, SLC5A8, ABCG2, and ZNF365 were lower in CSFs than UASFs, while EVs carrying SLC17A3 were not different between these two groups. SLC17A3 is a voltage-driven transporter of intracellular urate and organic anions from blood into renal tubular epithelial cells, and it thus plays an important role in metabolic disorders including serum uric acid concentration. Our current results suggest that renal tubular cells might respond to a specific type(s) of urinary crystals and tubular fluid compositions and release EVs containing specific UA transporters, and those changes may in turn reflect underlying UASD risk. These EVs could also potentially serve as a signaling mechanism that mediates UA stone risk (positively or negatively). For example, increasing tubular fluid uric acid concentration might downregulate proximal tubular cell secretion of EVs carrying SLC17A3 and SLC5A8 as a negative regulatory or unknown mechanism.EVs can serve as potential mediators of intercellular signal communication via their bioactive molecules  ,17,18,25EV surface expression of SLC2A9, SLC5A8, SLC17A3, SLC22A12, ABCG2, and ZNF365 might reflect altered UA transport capacity of tubular epithelial cells in a given individual, and could also signal other distally located tubular epithelial cells. The populations of urinary EVs carrying SLC2A9, SLC17A3, and ZNF365 were greater than SLC22A12, SLC5A8, and ABCG2, and differed between UASFs and CSFs. These results suggest that urinary EVs could potentially represent pathogenic biomarkers of CSF vs. UASF risk. Thus, the use of EVs as noninvasive diagnostic biomarkers would enhance their clinical applicability.This study has certain limitations. Only six pre-selected UA-transporters were measured in urine. This study also analyzed CSFs as a group, which is clinically relevant and commonly done but also represents a phenotypically diverse group. More evidence and mechanistic studies are needed to further define the precise relationship between urinary EVs carrying different transporters and stone pathogenesis. Furthermore, given the limited number of UASFs, we were not powered to do multivariable analysis and take into account the possible independent effect of urinary composition (as opposed to stone former type) on EV numbers. The candidate EV proteins were detected using flow cytometry with fluorophore-conjugated antibodies. In the future, it would be optimal to rigorously validate the expression of protein markers on purified urinary EVs using quantitative Western blot and/or mass spectrometry. Furthermore, the number of UASFs was relatively modest in comparison to the number of CSFs. The EV candidate biomarker pool could also potentially be increased, perhaps using an unbiased approach, such as by systematic bioinformatic analysis, and not only assessing EV-associated proteins but also bioactive nucleic acids . Nevertheless, this is the first study to assess UA transporter-carrying EV populations in human urine from UASFs, CSFs, and NSF controls.This study demonstrated that reduced urinary excretion of EVs carrying UA transporters by UASFs and CSFs might reflect the lower urine pH, volume, and resulting increased number of intratubular UA crystals that are associated with these two disease groups. The varied populations of EVs between disease groups might also reflect ongoing cell–cell communication. For example, renal UA transporter-carrying EVs could merge into a target cell membrane of recipient cells, which could in turn alter UA absorption and secretion, or otherwise alter the expression of this family of UA-transporters through mechanisms yet to be determined . This process could protect against further renal injury when cells in one part of the nephron are exposed to low pH and/or UA crystals. If the physiological processes resulting in a lower urinary pH and/or hyperuricosuria and low urine flows are pronounced, the mechanisms that physiologically alter EV excretion from renal tubular cells might be overcome. Cellular responses to the UA and COM crystals could also play a role in the progression of chronic kidney disease that has been associated with hyperuricemia , and nep


Several important and novel aspects regarding signaling by cGMP were reported in the various publications of this Special Issue. The topics comprise the regulation of cGMP synthesis by soluble guanylyl cyclase  and its structural features, signaling by cGMP-dependent protein kinases (PKG) and its substrates as well as the cGMP degradation and modulation by phosphodiesterases (PDE). The features of the diverse manuscripts and reviews of this Special Issue include possible (patho)physiological functions and pharmacological application of signaling by cGMP in a variety of syndromes comprising skeletal muscle, renal, cardiovascular, gastrointestinal, hematological and cancer diseases.The modulation of sGC is currently emerging as a pharmacological tool in various diseases. The NO-independent and heme-dependent sGC stimulator riociguat was first introduced into therapy of pulmonary arterial hypertension and chronic thromoboembolic pulmonary hypertension . Since tA further class of sGC modulators are the nitric oxide- and heme-independent sGC activators. This class was not introduced into pharmacological applications up to now possibly because the sGC activator cinaciguat showed strong blood pressure reductions during clinical tests. However, there might be possible application of sGC activators in chronic diseases, e.g., diabetic nephropathy . A novelNew structural features of sGC are essential for understanding the precise molecular mechanism and modulation of this enzyme. In the review by Wittenborn et al. the current view of full length sGC revealed by novel structures obtained by cryo-electron microscopy is summarized. The authors discussed the inactivated and activated states of the enzyme to describe the detailed biochemical mechanism and its function, which could be helpful to elucidate new sGC modulators for pharmacological treatments .Signaling by cGMP dependent protein kinases (PKG) and their substrates are important aspects for understanding the specific pathways and functions of these kinases in different physiological systems. New aspects regarding the role of cysteine-rich LIM-only protein 4 (CRP4) in cGMP signaling were investigated by Längst et al., which revealed that CRP4 acts as a feedback loop for relaxation of the vasculature .3R-associated cGMP kinase substrate 1 (IRAG1) in mice exerts gastrointestinal disorders and bleeding, anemia, iron deficiency and splenomegaly. This is accompanied by downregulation of the specific β-isoform of PKGI (PKGIβ) protein. This leads to the hypothesis, that a loss of PKGIβ/IRAG1 signaling causes these physiological defects [The involvement of cGMP signaling deficiency in gastrointestinal and hematological disorders was reported by Majer et al. Loss of the IP defects .Phosphodiesterases (PDE) modulate the level of cyclic nucleotides in cells and are very effective drug targets. There are various PDE known, which are involved in diverse (patho)physiological functions. PDE2 is stimulated by cGMP and induces cAMP hydrolysis. In the manuscript by Wagner et al. PDE2 was overexpressed in mice and thereby protection against ventricular arrhythmia was observed . Hence, cGMP-hydrolyzing phosphodiesterase (cGMP-PDE) are appealing targets for a variety of diseases and might be also valuable in the treatment of cancer. Di Iorio et al. reviewed the possible role of cGMP-PDE in breast cancer and discussed the potential application of cGMP-PDE inhibitors. For this, the notable and controversial studies concerning an off-label use of these inhibitors in cancer therapy are summarized .Signaling by cGMP is an appealing topic in biochemistry, (patho)physiology and pharmacology. It is expected that the structural, biochemical and dynamic aspects of the signaling by cGMP network are further elucidated. Furthermore, there are several new treatment options of cGMP modulation arising in the future in various diseases. These various aspects of signaling by cGMP suppose that this attracting field will further extend in future.