Triterpenic acids are phytocompounds with a widespread range of biological activities that have been the subject of numerous in vitro and in vivo studies. However, their underlying mechanisms of action in various pathologies are not completely elucidated. The current review aims to summarize the most recent literature, published in the last five years, regarding the mechanism of action of three triterpenic acids , corelated with different biological activities such as anticancer, anti-inflammatory, antidiabetic, cardioprotective, neuroprotective, hepatoprotective, and antimicrobial. All three discussed compounds share several mechanisms of action, such as the targeted modulation of the PI3K/AKT, Nrf2, NF-kB, EMT, and JAK/STAT3 signaling pathways, while other mechanisms that proved to only be specific for a part of the triterpenic acids discussed, such as the modulation of Notch, Hippo, and MALAT1/miR-206/PTGS1 signaling pathway, were highlighted as well. This paper stands as the first part in our literature study on the topic, which will be followed by a second part focusing on other triterpenic acids of therapeutic value. Ever since the discovery by Pisha et al. in 1995 of the selective anti-melanoma efficiency of betulinic acid, pentacyclic triterpenes have entered the scrutiny of numerous research groups in order to identify their ability to fight various diseases in particular malignant tumors. Triterpenes represent the largest group of terpenoids, natural compounds isolated from various plants, animals, microorganisms, and oils ,3. PentaOne major therapeutic benefit when using pentacyclic triterpenes as pharmacological agents is their selective biological effects, which largely prevent the occurrence of side effects; pharmacological selectivity is particularly beneficial when the triterpenes are used as cytotoxic agents against tumor cells keeping healthy cells unharmed. This behavior comes in sharp opposition to synthetic drugs, which act undifferentiated on normal and tumor cells, therefore triggering severe side effects with potential lethal consequences. The combination of therapeutic efficiency with the lack of toxic activity makes pentacyclic triterpenes attractive alternatives to conventional treatments; however, in order to be accepted as therapeutic agents, triterpenes must undergo several testing stages in order to reveal their efficacy/toxicity ratio, which reflects their safety for human use.One well-known drawback of these phytocompounds is the reduced bioavailability that limits their use. To overcome this limitation, pentacyclic triterpenoids have been subjected to numerous derivatizations, which led to some derivatives with superior activity compared to parent compounds . For insThe investigation of the mechanism of action (MOA) before entering clinical trials is considered by some researchers as an essential step in the development process of a new drug  since itIt has become very clear that, considering their very large plethora of biologic effects, triterpenic acids presumably act on multiple pathways; indeed, there are many reviews published in the past 10 years regarding their mechanism of action responsible for various activities, such as anticancer ,20,21,22Centella asiatica used in Traditional Chinese and Indian Ayurvedic medicine as treatment for various skin conditions including wound healing, gastrointestinal and genitourinary diseases, anxiety, and cognitive disorders . AA. AA83]. In terms of protection against neurodegenerative diseases, AA showed efficiency as an anti-inflammatory agent in Parkinson’s disease using 1-methyl-4-phenyl-pyridine (MPP+)-induced SH-SY5Y cells as in vitro model . The phyA key mechanism of antiepileptic drugs consists in the inhibition of the glutamate release, which results in the reduction of neuronal excitability; the application of AA in hippocampal synaptosomes in rats induced the inhibition of glutamate release in a concentration-dependent manner . In-deptCentella asiatica extracts on the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs), which are widely distributed throughout the central nervous system; they are ionotropic glutamate receptors that mediate rapid excitatory neurotransmission and that presumably represent the cellular mechanism involved in learning abilities and memory. The extract of C. asiatica clearly enhances the surface expression of AMPARs in the entorhinal cortex of rat brains, thus increasing the amplitude of the spontaneous excitatory postsynaptic currents; one may conclude that the vegetal extract containing mainly AA and asiaticoside is responsible for triggering an increased response of AMPARs at postsynaptic level and, subsequently, producing cognitive enhancements. Moreover, the authors revealed that only small doses of extract manage to modulate AMPAR-mediated current responses, thus suggesting a synergistic interaction between components; the optimal combination between C. asiatica extract is presumably analogous to the nerve growth factor . A. A121]. Even though the main OA pharmacological activities have been extensively studied for a rather long time, a plethora of new potential utilizations are currently under investigation.Thyroid cancer is the most common endocrine malignancy whose certain undifferentiated forms (anaplastic carcinomas) show small survival expectancy, not exceeding 6 months. One molecular signaling pathway responsible of thyroid cancer is the overexpression of FOXA1–a transcription factor of the Forkhead box (FOX) protein family, and a pioneer factor that facilitates oncogenic transcription factors; its hyperreactive signaling due to gene amplification or overexpression was reported in many cases of thyroid lesions and tumors . Duan L.OA also exerted anticancer effects on rectal cancer cell lines through several molecular mechanisms; it stimulated the reactive oxygen species (ROS) and NADPH oxidase 2 (NOX2) and inhibited the overexpression of HIF-1α in a dose-dependent manner, leading to G1/S cell arrest and, subsequently, to the inhibition of rectal cancer cells proliferation . HIF-1α OA proved its efficacy against osteosarcoma by inhibiting the proliferation and viability of human osteosarcoma cell lines Saos-2 and MG63 in a dose-dependent manner. The mechanism behind this effect resides in the inhibition of the Notch signaling pathway , as reveOA may act as a alleviator of epithelial–mesenchymal transition (EMT), which plays a significant role in the progression of interstitial fibrosis; the phytocompound dose-dependently activates the NF-E2-related factor 2 (Nrf2) which protects tissues against oxidative stress and activates klotho protein expression; in turn, klotho acts as a direct inhibitor of TGF- β1, therefore blocking its binding to the surface receptors and reducing EMT responses . The EMTThe anticancer activity of OA in hepatocellular carcinoma cells (HCC) is also mediated through the microRNA-122 expression ; microRNOA was also combined with other active principles resulting in synergistic anticancer effects; the combination of OA with Hypocrellin A (HA) was investigated by Wang et al. in HepG2 HCC cells where the anticancer mechanism resides in the modulation of the Hippo/YAP signaling pathway. The Hippo signaling pathway includes a plethora of tumor suppressor genes that regulate cell proliferation and organ growth, its overexpression being modulated by the transcriptional factors of TEA family (TEAD) and by the key transcriptional cofactor YAP . The autKhan et al. assessed the anticancer activity of OA in hepatocarcinoma by co-loading cisplatin and OA in calcium carbonate nanoparticles (CDDP/OA-LCC NPs) and analyzing their pro-apoptotic effect in HepG2 cell lines. The authors reported that CDDP/OA-LCC NPs exerted a synergistic pro-apoptotic effect compared to the free drug solutions and blank calcium carbonate nanoparticles. The molecular mechanism responsible for the apoptotic effect consisted in the down-regulation by OA of the PI3K/AKT/mTOR pathway through the inhibition of mTOR phosphorylation triggered by the AMPK pathway activation, resulting in the inhibition of cell proliferation and survival. In addition, OA up-regulated the p53 proapoptotic pathway through the up-regulation of the pro-apoptotic proteins  finally leading to an AMPK-dependent apoptotic effect. Furthermore, OA helped overcoming drug resistance by down-regulating the NF-kB pathway which enhances the apoptotic potential of chemotherapeutic agents such as cisplatin, thus leading to drug resistance in cancer cells .Kim et al. conducted a study on the anticancer activity of OA in DU145 prostate cancer cells, MCF-7 breast cancer cells, and U87 human glioblastoma cells. In terms of molecular mechanisms, OA exerted an apoptotic and anti-proliferative effect on all cancer cells by stimulating the expression of proapoptotic proteins p53 , cytochrActinidia chinensis was tested both in vitro in HGC-27 gastric carcinoma cell lines and in vivo on a zebrafish xenograft model, exhibiting a strong apoptotic effect on cancer cells in direct proportion to the increase in phytocompounds’ concentrations. The molecular mechanism that may explain the anticancer activity is the up-regulation of cytochrome C, which in turn modulates the cleaved caspase 3, hence inhibiting HGC-27 proliferation and stimulating their apoptosis . A. A158]. Polychlorinated biphenyls exposure is frequently associated with obesity and diabetes; Su et al. have emphasized the ability of OA to inhibit oxidative stress induced in Aroclor 1254-treated mice. The authors reported that OA decreased ROS, NOX expression, and PPARγ signaling and increased hepatocyte nuclear factor 1B (HNF1b) expression in mouse adipocytes. HNF1b plays a key role in the hepatic fat synthesis regulation, glucose homeostasis, and insulin resistance; it also activates the antioxidant enzyme transcription and suppresses the transcription of oxidant enzymes such as NADPH oxidase 1 (NOX) while down-regulating the expression of PPARγ in the process of adipocyte differentiation . PPARγ bIt is well known that poor diabetes management with frequent episodes of high blood glucose levels leads to impaired endothelial functions resulting in insufficient NO production; Zhang et al. have analyzed the ameliorative action of OA against endothelial dysfunction. OA activated the PPARγ target genes  and modulated the eNOS/Akt/NO pathway, which is involved in NO production through the oxidation of L-arginine; the eNOS activity is modulated by Akt that induces eNOS-Ser phosphorylation leading to NO production in response to diverse stimuli. The NO production is also stimulated by PPARγ and leads to endothelial vasodilation. OA was able to restore the endothelial function impaired by high glucose levels due to the activation of the PPARγ-mediated Akt/eNOS signaling pathway .An important aspect of diabetic homeostasis is the maintenance of glycemic control through the inhibition of α-glucosidase activity; α-glucosidase is a carbohydrate hydrolase that regulates blood sugar by hydrolyzing the 1,4-α-glucopyranosidic bond, leading to α-glucose production, hence increasing the blood sugar levels . MoleculThe combination of OA and UA was able to treat disorders in carbohydrate uptake through inactivating human salivary α-amylase (HSA), an important enzyme in starch and glycogen digestion. The two compounds have shown non-competitive inhibition against HSA, but the inhibitory ability of OA is lower than that of UA. The crucial residues, Arg 195 and Asp 197, might explain the enzyme interaction with all inhibitors by hydrogen bonds; UA was able to form two hydrogen bonds with Arg 195 because of the adjacent methyl groups of the E ring, thus forming additional contacts involving the hydrophobic portion of Asp .OA exhibits strong antiviral activity against the Herpes simplex virus (HVS), both acyclovir (ACV)-sensitive and ACV-resistant HSV-1 strains. In terms of molecular mechanism, OA demonstrated antiviral activity in the early stages of the HSV infection by suppressing UL8, the critical helicase-primase complex for viral replication. UL8 is a subunit of the helicase-primase heterotrimer that interacts with the other two components, UL5 and UL25, and modulates the formation of the UL5/UL25 subcomplex, leading to viral replication .Combining antibiotics with anti-resistance compounds has become a new strategy for fighting antibiotic resistance; Catteau et al. have analyzed the synergistic effect of OA and UA, respectively, with beta-lactams against methicillin-resistant Staphylococcus aureus (MRSA). Both UA and OA exhibited antibacterial effects in a synergistic manner with β-lactams (ampicillin and oxacillin) and inhibited the β-lactamase activity of MRSA by delocalizing PBP2 from the septal division site and inhibiting peptidoglycan synthesis . PenicilLin et al. have studied the lipolytic effect of OA through exploring its ability to inhibit Liver X receptor α (LXRα) in vitro in HepG2 cell lines. Liver X receptor α (LXRα) belongs to the activated nuclear receptor (NR) family and is highly expressed in organs responsible for cholesterol homeostasis; it activates the hepatic lipogenic pathway by stimulating the transcriptional region of LXR response element, leading to the up-regulation of target genes and subsequently up-regulating lipogenesis. OA exhibited an inhibitory effect on the LXR response element by diminishing its transactivation as well as on sterol regulatory binding protein-1c (SREBP-1c); moreover, OA was able to reduce mRNA and protein expression of LXRα target genes, subsequently decreasing lipid accumulation in hepatic cells. Furthermore, OA was able to down-regulate valproate and rifampicin-induced LXRα, showing potential for future drug-induced hepatic steatosis treatment . OA showOA exhibits a strong antihypertensive activity through phospholipid levels modulation; Zhang et al. have investigated OA properties in vivo on hypertensive rats. The lipid metabolism was regulated by OA through the inhibition of secretory phospholipase A2 (sPLA2) and fatty acid synthase (FAS), leading to improved blood pressure and lipidic profile. sPLA2 promotes foam cell formation by increasing the proinflammatory bioactive lipid levels and decreasing HDL levels; as a result, OA was able to inhibit the accumulation of triglycerides and cholesterol . The antBenign prostatic hyperplasia (BHA) is one of the most frequent diseases in men over 50; OA was found to exert efficient ameliorating effects in vitro in BPH-1 cell lines and in vivo against a testosterone-induced BHA animal model. OA showed suppressive effect on testosterone-induced BPH by inhibiting in vitro cell cycle progression through the down-regulation of cyclin-Cdk complexes; in vivo, OA down-regulated 5α-reductase expression, leading to a reduced DHT production and subsequently stopping prostate weight gain. Furthermore, the therapeutic effect exhibited by OA was similar to the one obtained following finasteride treatment, proving OA as a future candidate for BHA treatment . Yang etActing as an antiinflammatory agent, OA was found to prevent aging-related testicular dysfunction by inhibiting several pro-inflammatory cytokines, such as IL-1β, COX-2, and TNF-α, and leading to an improved testicular weight and index. Further in-depth studies revealed that OA inhibited the phosphorylation of NF-kB and attenuated DNA damage and apoptosis through the modulation of the Bcl-2/Bax ratio as a result of Bcl-2 up-regulation combined with Bax down-regulation .OA proved useful in bone tissue regeneration by modulating Notch signaling and growth factor bone morphogenetic protein 2 (BMP2); the phytocompound induced mesenchymal stromal cell (MSC) osteogenic differentiation in a dose-dependent leading to the enhanced osteogenic proteins expressions of ALP, Runx2, and Collagen I, and subsequently stimulating bone formation . AdditioAn efficient OA effect against osteoclastogenesis and bone resorption can be explained by its ability to up-regulate the expression of estrogen receptor-alpha (Erα) by direct binding, causing the up-regulation of miR-503; subsequently, miR-503 inactivates the mRNA of RANK, hence inhibiting osteoclastogenesis. ERα/β modulates gene transcription by binding to estrogen response element (ERE) and is an essential site for estrogen to express its anti-osteoporotic effect .Osteoarthritis is a common joint degenerative disease, manifested in cartilage degradation, inhibited bone remodeling, and synovial inflammation. The molecular mechanism responsible for osteoarthritis degeneration is the stimulation of inflammatory cytokines and active metalloproteinases (MMPs) by fibroblast-like synoviocytes (FLS) production of chemokines and cytokines. Bao et al. have reported that OA may stop osteoarthritis evolution by inhibiting synovial inflammation through the up-regulation of sirtuin 3 (SIRT3) expression, leading to the inactivation of the NF-kB pathway . SIRT3 iIn terms of molecular mechanism, the inflammatory reaction is mediated by pro-inflammatory cytokines, which in turn are modulated through the NF-kB and STAT1 signaling pathways; they play a major role in the immediate response in anaphylactic shock and lead to direct effects on tissues and mucus production. OA exhibited an anti-allergic activity by inhibiting the formation of pro-inflammatory cytokines through blocking the phosphorylation of STAT1 and suppressing p65 NF-kB translocation, thus causing the inhibition of allergic inflammatory response . FurtherAn interesting approach of the anti-inflammatory effect of OA was conducted by Dong et al. in Salmonella typhimurium-induced diarrhea in mice; the authors reported that OA was able to alleviate the intestinal inflammation and barrier damage by reducing the levels of COX-2 and iNOS, and also down-regulated the IL-1β, IL-6, and TNF-α pro-inflammatory cytokines levels; the inhibition of pro-inflammatory cytokines also prevents the acetaminophen- or concanavalin A-induced necrosis of hepatic tissues ,193. FurOA exerts a profound protective effect against early brain injury after subarachnoid hemorrhage where the extracellular HMGB1 can induce cytokine release and leukocyte recruitment to trigger inflammatory response. Oleanoic acid can reduce the level of serum HMGB1 by inhibiting the transfer of HMGB1 from nucleus to cytoplasm, thus reducing early brain injury and neuronal apoptosis after subarachnoid hemorrhage. On the other hand, SIRT1, one of the most studied deacetylases, inhibits the translocation of HMGB1 to the cytoplasm by deacetylating HMGB1 lysine, thereby reducing its serum level; OA acts as SIRT activator, thus enhancing HMGB1 deacetylation and then inhibiting the transfer of HMGB1 from nucleus to cytoplasm, thereby inhibiting inflammation .In addition to anti-inflammatory properties, OA exerts a potent antioxidant activity and protects cells and tissues against oxidative stress; the protective effects of OA against oxidative stress in Alzheimer’s disease were mediated via regulation of STC-1 and UCP2 signaling pathways. UCP2 inhibition significantly reversed the regulatory effect of OA on cell viability, caspase-3 activity, reactive oxygen species content, and β amyloid level in N2a/APP695swe cells . An esseOA may also act as a neuroprotective agent against neurodegenerative pathologies such as Parkinson’s disease by attenuating striatal microglial activation. The ability of OA to attenuate 6-hydroxydopamine-induced intracellular reactive oxygen species and prevent cell death in PC12 cells is not clearly understood. Some key data suggest that OA may interact directly with microglia, thus attenuating microglial activation that would result in an unremitting neuroinflammatory response. Furthermore, this phytocompound removes intracellular ROS, preventing microglial migration toward neurons; nonetheless, the study demonstrated the role of alfa-Synuclein in microglial migration regulation via hydrogen peroxide, showing that it binds to CD11b, a receptor expressed in microglia, and leads to subsequent neuronal damage . The antThe orofacial antinociceptive effect of OA was revealed through the possible modulation of TRPV1 receptors; TRPV1, a nonselective cation channel, may be activated by a wide variety of stimuli. The antinociceptive effect of OA was significantly reduced in adult zebrafish pre-treated with ruthenium red, a TRPV1 receptor antagonist; furthermore, when a TRPV1 channel antagonist is used, the antinociceptive response is blocked. In addition, depletion of TRPV1 + C fibers by capsaicin eliminated the analgesia produced by OA; collectively, the inhibition of TRPV1 channel by OA confirms its potential pharmacological relevance against acute pain .Hepatoprotection is one of the most notable pharmacological effects of OA. Low doses of OA protect against hepatotoxicity induced by a lot of stimuli, such as carbon tetrachloride, acetaminophen, cadmium, and phalloidin. The marked activation of Nrf2 by OA could explain, at least in part, the OA hepatoprotection against the above-mentioned toxic stimuli. In addition to Nrf2 activation, other mechanisms, such as a decrease in CYP2E1, decrease in Oatp1b2, modulation of the immune response, and inflammation may offer hepatoprotection. Furthermore, OA may act as a TGR5 agonist, but TGR5 activation is also associated with risks of histopatological changes, tumorigenesis, and pruritus. Higher doses can produce liver injury, including cholestasis, but this paradoxical effect could also depend on coexistent pathological conditions .Further studies have shown that OA would suppress the cellular production of resistin in adipocytes by specifically blocking the Tyk2-STAT1 pathways in the middle phase of adipocyte differentiation. The completion of adipocyte differentiation was altered by the phytocompound by suppressing SOCS3, whose cellular expression is up-regulated during the later phase of differentiation; OA also suppressed PPARγ induction, revealing that the JAK-STAT signaling pathway was not activated during the completion of adipocyte differentiation .OA proved useful in androgenic alopecia in vitro models by inhibiting the activity of 5α-reductase activity and regulating the alopecia-correlated genes expressions. Testosterone is converted into dihydrotestosterone (DHT) by 5α-reductase, being responsible for androgenic alopecia, by increasing TGF-β1 and TGF-β2, leading to a down-regulated proliferation of epithelial cells, and by up-regulating Dickkopf related protein-1 (DKK01) causing an inhibitory effect on epithelial cells growth in hair follicles. The results showed that OA inhibited the activity of 5α-reductase in vitro in a dose-dependent manner, and also reduced DHT production, leading to dermal papilla cells proliferation and reduced impact of DHT on gene expression .Lamiaceae family, possessing little to no toxicity ..219].The previously mentioned up-regulation of the pro-apoptotic caspase proteins  as well as the down-regulation of the NF-kB/Akt signaling pathway supports the anticancer activity of UA against gallbladder carcinoma where the in vitro UA anti-proliferative and proapoptotic effects manifest in a dose-dependent manner in GBC-SD cells. UA inhibition of Akt further contributed to suppressing NF-kB p-65 and mRNA levels of matrix metalloproteinase 2, hence stopping cell invasion .Mu et al. demonstrated the apoptotic effect of UA in vitro on LNCaP human prostate cancer cells; UA modulated the Rho-associated protein kinase 1 (ROCK1)/phosphate and tension homolog (PTEN)- cofilin-1/cytochrome c signaling pathway , leadingSeveral studies have been conducted on the potential use of UA against breast cancer, resulting in the identification of certain molecular targets. The apoptotic effects of UA were compared to the anticancer effects of betulinic acid on MCF-7, MDA-mB-231, and SK-BR-3 receptors where UA exhibited a significantly stronger activity. The molecular mechanism identified in apoptosis and autophagy resides in inhibiting the activation of the AKT signaling pathway, suppressing the phosphorylation of ERK1/2 signals and overall leading to the depolarization of mitochondrial membrane potential. Furthermore, UA may induce premature senescence in breast cancer cells by activating p21, a protein responsible for cell cycle progression at G1, hence inducing G0/G1 cycle arrest . The samKim et al. reported that UA suppressed the invasion and migration rates of SNU484 and SNU638 gastric cells in a dose-dependent manner by regulating the Hippo pathway through promoting its upstream target genes , and Ras association domain family (Rassf1). The Hippo pathway is responsible for cell growth and survival; after being activated, it displaces phosphorylated Yap in the cytoplasm, leading to cell degradation, hence stopping cell proliferation; the experimental data also showed that UA was able to inhibit tumor growth in xenograft animals .Skin cancer can also be targeted by UA, which activates the peroxisome proliferator activated receptor α (PPARα) and AMPK in mouse squamous cell carcinoma Ca3/7 cells and mouse skin papilloma MT1/2 cells . PPARα hWhen tested against cervical cancer, UA exhibited a strong apoptotic effect both in vitro on CaSki, HeLa, C4-1, and SiHA human cervical cell lines and in vivo on xenograft tumor models. In terms of molecular mechanisms, UA up-regulated p53 and pro-apoptotic Bax protein and down-regulated the expression of anti-apoptotic Bcl-2 protein and protein 1 (cIAP1) apoptotic inhibitor, thus inducing apoptosis and cell death  233]. C. C233]. The L858R/T790M mutation of the epidermal growth factor receptor (EGFR) represents a major cause of EGFR treatment in non-small-cell lung (NSCLC) carcinoma. Yang et al. studied the effect of UA on overcoming the challenging treatment of NSCL by mediating the CT45A2 gene transcription. CT45A2 is a proto-oncogene that belongs to the CT45 family and has an important role in tumorigenesis. The results showed that CT45A2 was up-regulated in H1975 NSCLC cells and expressed EGFR with the T790M mutation. Furthermore, UA inhibited the transcription factor TCF4, that plays an important role in CT45A2 gene transcription, by down-regulating the β-catenin/TCF4 transcriptional activity through blocking the nuclear translocation of β-catenin, hence inhibiting the proliferation and motility of NSCLC cells .UA exhibited a ROS-dependent autophagy in esophageal squamous cell carcinoma (ESCC) TE-8 and TE-12 cell lines previously treated with ROS inhibitors; the authors reported that UA reduced cell migration and invasion and induced apoptosis and autophagy in a dose-dependent manner. In terms of molecular mechanisms, UA induced ESCC apoptosis by enhancing the levels of cleaved PARP and caspase-9 proteins, resulting in sub-G1 cellular cycle phase arrest. Furthermore, UA modulated the Akt/mTOR pathway, which resulted in increased ROS production by up-regulating the LC3-II levels and down-regulating the p62 protein levels, finally resulting in ESCC autophagy .The correlation between abnormal levels of cholesterol and different types of cancer has been widely explored; more specifically, the expression of sterol regulatory element-binding protein 2 (SREBP2) has been correlated with the evolution of hepatocellular carcinoma. Kim et al. highlighted the apoptotic effect of UA against HCC through the modulation of cholesterol supplementation; at low intracellular cholesterol levels, SREBP2 initiates a transcriptional programming through the activation of target genes, inducing de novo cholesterol synthesis, which promotes growth signaling factors such as PI3K/AKT and EGRF/MAPK. When intracellular cholesterol levels are elevated, SREBP2 is not processed to maturation and cholesterol synthesis is not stimulated. UA activates SREBP2, thus inducing cell cycle arrest and apoptosis in HCC cells by inhibiting phosphorylation of the oncogenic AKT and MAPK pathways .Reactive oxygen species play an important role in the development of various congenital disorders such as those caused by gestational diabetes; high levels of ROS in mothers with prenatal diabetes can lead to DNA or RNA harm in the embryos. Dai et al. analyzed the antioxidant effect of UA in pregnant rats with pre-induced streptozotocin gestational diabetes; the underlying molecular mechanism resides in the modulation of AGEs-RAGE signaling pathway , which hDiabetic cardiomyopathy is one of the most common complications in poorly conducted diabetes treatment with patients exhibiting left ventricular dysfunction and cardiomyocyte hypertrophy; UA revealed the ability to alleviate oxidative stress and inflammatory processes in diabetic cardiomyopathic rats. It inhibits the production of pro-inflammatory cytokines TNF-α, MCP-1 and TGF-β1 and up-regulates MMP-2 protein levels, leading to attenuated myocardial injuries such as cardiac fibrosis .Toxoplasma gondii infections occur in many countries and have become a risk since they cause serious consequences in all age groups, particularly in pregnant women. Choi et al. reported that UA inhibited the expression of IL-1β, IL-6, TNF-α, and TGF-β1 pro-inflammatory cytokines, and stimulated the anti-inflammatory cytokines IL-10, Il-12, and granulocyte macrophage colony stimulating factor (GM-CSF) as well as the production of NO and ROS in parasite-infected immune cells. In addition, the phytocompound inhibited T. gondii proliferation by down-regulating the expression of ROP 18, MIC 8, and IMC sub 3 subcellular organelles in T. gondii-infected cells; therefore, one may state that UA acts as an antiproliferative agent against T. gondii while simultaneously modulating the immune response in parasite-infected immune cells [Zoonotic infections have become significantly widespread around the globe; ne cells . UA coulne cells . IL-4 isne cells , able toK. pneumoniae (CRKP) that represents a serious public health threat; the results showed that UA was able to alter bacterial membrane integrity and inhibit biofilm formation, hence providing a potential future treatment against CRKP [Quian et al. examined UA’s antimicrobial activity against carbapenem-resistant nst CRKP . Alternaria alternata, a latent fungus that contaminates several types of fruits and whose metabolites can be detrimental to humans in which UA up-regulates ROS production and accumulation, leading to pathogen lysis [The disturbance of membrane permeability and integrity can be induced by UA in fungi as well; such an example is en lysis .UA was found active against phenylephrine-induced right ventricle hypertrophy in neonatal rats model; the report showed that UA regulated the PPARα-dependent fatty acid metabolism through the up-regulation of PPARα and CPT1b genes expressions which are down-regulated in hypertrophy, resulting in the alleviation of tissue fibrosis, cell apoptosis and metabolic abnormalities .Qui et al. have investigated the anti-atherosclerotic effect of UA both in vitro and in vivo; UA activity was explained by the up-regulation of lecitin-like oxidized low-density lipoprotein receptor 1 (LOX-1) expression and the down-regulation of the TLR4/MyD88 signaling pathway. Moreover, UA inhibited the NF-kB pathway, leading to the suppression of ROS production . LOX-1 iUA showed an efficient activity against in vitro leptin-induced atherosclerosis in rat vascular smooth muscle cells; in terms of molecular mechanism, UA exhibited an inhibitory effect on ERK1/2 activation, NF-kB expression, and leptin-induced MMP2 activity, hence decreasing ROS production. The down-regulation of MMP2 secretion by UA induced the inhibition of MAPK/ERK signaling pathway, hence inhibiting cell proliferation and atherosclerosis .In a similar manner than its isomer OA, UA exerts strong neuroprotective effects against traumatic brain injuries in mice by activating the Nrf2 pathway. Under physiological conditions, Nrf2 is bound to the Kelch-like ECH associated protein (Keap1) where it is subject to degradation; however, under pathological conditions, Nrf2 is released into the nucleus and binds to antioxidant response element (ARE), leading to the activation of downstream protective factors such as heme oxygenase 1 (HO1) and NADPH quinine oxido-reductase 1 (NQO1), which regulate redox balance. Experimental results showed that UA was able to activate the Nrf2 pathway, therefore up-regulating anti-oxidant enzymes, reducing oxidative stress, and producing neuroprotective effects . UA was able to mimic human natural killer-1 (HNK-1) properties in C57BL/6J mice models of spinal cord injury where the phytocompound inhibited the pro-inflammatory markers; HNK-1 is a glycan epitope involved in several neural functions, including the regeneration of the nervous system. The results showed that UA down-regulated MAPK and PI3K/AKT/mTOR pathways, which are activated in the acute phase of inflammation, leading to the suppression of proinflammatory markers such as IL6 and TNF-α; subsequently, it stimulated the structural remodeling for injury regeneration .Wang et al. indicated that the anti-inflammatory effect of UA in alleviating cerebral ischemia and reperfusion injury is accomplished by inhibiting the HMGB1/TRL4/NF-kB pathway and causing the inhibition of TNF-α, IL-1β, and IL-6 pro-inflammatory cytokines; subsequently, UA is able to attenuate ischemia and neuronal apoptosis .Mou et al. reported that UA was able to ameliorate simulated autoimmune thyroiditis in human follicular epithelial cells (Nthy-ori 3-1) by inhibiting the MALAT1/miR-206/PTGS1 and NF-kB signaling pathways. MALAT1 possesses a key role in cellular proliferation and apoptosis; miR-206 is an important member of the MIR gene family, acting as a crucial regulator in muscular differentiation and neuromuscular junction repair while PTGS1 is an enzyme that regulates prostaglandin synthesis in various organs; collectively, the MALAT1/miR-206/PTGS1 pathway is deeply involved in inflammatory processes. UA alleviated IL-1β induced Nthy-ori 3-1 cell damage by down-regulating MALAT1/miR-206/PTGS1 and NF-kB expression, hence inhibiting the pro-inflammatory cytokines .The anti-inflammatory effect of UA was investigated in cigarette smoke-induced emphysema in rats; the authors have reported that UA was able to alleviate the emphysema severity by modulating the PERK pathway and decreasing 8-OHdG and MDA oxidative stress factors. The phytocompound inhibited the activation of PERK, leading to the down-regulation of Bax pro-apoptotic protein and up-regulation of Bcl-2 anti-apoptotic protein; furthermore, UA was able to inhibit the inflammatory caspase 3 and caspase 9, and stimulate the expression of the Nrf2/ARE pathway, thus alleviating experimental emphysema . The autUA exhibited a suppressive effect against muscle wasting in induced chronic kidney disease both in vitro and in vivo; the phytocompound down-regulated the expression of myostatin and TNF-α, IL-1β, and IL-6 pro-inflammatory cytokines, led to the inhibition of ubiquitin E3 ligase, and decreased proteolysis . ComplemKim et al. have explored the alleviating effect of UA in rheumatoid arthritis in RASF ; UA facilitated RASF apoptosis by down-regulating the expression of myeloid cell leukemia-1 (Mcl-1) through the enhancement of Noxa selective binding to Mcl-1. Mcl-1 belongs to the anti-apoptotic Bcl-2 family, playing a key role in intrinsic and extrinsic cell death signals and enhancing apoptosis resistance . The ability of UA to ameliorate induced-nonalcoholic fatty liver was explored through modulating the LXRα receptor on a T090 induced mouse model; the results showed that the phytocompound significantly decreased the LXR response element by competitive binding; furthermore, UA up-regulated AMPK phosphorylation in hepatic cells, but down-regulated the SREBP-1 promoter region, leading to reduced hepatic and cellular contents . The phyTriterpenic acids have been found to exert a plethora of pharmacological activities such as anticancer, anti-inflammatory, antidiabetic, antioxidant, cardioprotective, hepatoprotective, neuroprotective, antimicrobial, etc. Their potential efficacy needed to be fully explored due to their pharmacological selectivity that prevents the occurrence of hardly tolerable side effects compared to the synthetic drugs used currently in therapy. In the last decades, many underlying molecular mechanisms were identified and described; however, in order to fully understand the best formulation options for triterpenic acids and to thus achieve their highest therapeutic potential, further studies must be conducted since–despite the huge progresses in the area–there are still many aspects to be revealed at the molecular level. Such investigations are crucial for future clinical trials and in order to reveal important information regarding the compound’s safety and posology, preventing late-stage failure in drug development.Our work aimed to summarize the molecular mechanisms involved in the pharmacological activities of three intensively researched triterpenic acids: AA, OA, and UA. The literature survey on these phytocompounds revealed a variety of signaling pathways that trigger specific pharmacological effects both in vitro and in vivo. Some studies, however, reported contradictory results, which might lead researchers to the conclusion that the pharmacological profile of a phytocompound is the result of triggering a combination of molecular pathways in a dose-dependent manner. This knowledge might contribute to future research that aim to develop triterpenic acids-based drugs that may improve the current therapeutic arsenal.


Nature Communications 10.1038/s41467-022-30928-x, published online 09 June 2022.Correction to: In this article the affiliation details for Yan-Chu Li, Yong Zhou and Qian-Qian Sha were incorrectly given as “MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, 310058 Hangzhou, China” but should have been “Fertility Preservation Laboratory, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, 510317 Guangzhou, China”. The affiliation details for Lu Chen, Zuo-Qi Deng and Heng-Yu Fan were incorrectly given as “Fertility Preservation Laboratory, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, 510317 Guangzhou, China” but should have been “MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, 310058 Hangzhou, China”. The original article has been corrected.


The MCA-PI decreased from day 1 until day 3 in both groups, but significantly only in the trAEDF group (p = 0.030 vs. p = 0.227. The DV-PI’s decrease (during day 1) and the CPR’s increase (between days 0 and 2) were not significant in both groups. UTAs-PIs did not vary. The prAEDF group had a significantly increased rate of antenatal worsening Doppler and a poorer perinatal outcome compared with the trAEDF group. In conclusion, Dex transiently restored the AEDF in UA in the majority of cases, a “positive” effect being a useful marker for better perinatal prognosis. UA-PI significantly decreased in all cases. The improvement in umbilical circulation probably was responsible for the short but not significant DV-PI reduction. MCA-PI decreased only in sensitive cases, probably due to an already cerebral “full” vasodilation in the prAEDF group. Furthermore, the CPR’s nonsignificant improvement was the result of a stronger effect of Dex on UA-PI than on MCA-PI. Finally, despite the same etiology, it was only a weak correlation between the severity of the umbilical and uterine abnormal spectrum.Corticoids are largely used for fetal interest in expected preterm deliveries. This study went further, evaluating the effect of maternal administration of dexamethasone (Dex) on the umbilical artery (UA), middle cerebral artery (MCA), and ductus venous (DV) spectrum, in growth-restricted fetuses, with the absent end-diastolic flow (AEDF) in UA, from singleton early-onset severe preeclamptic pregnancies. Supplementary, the impact on both uterine arteries (UTAs) flow was also evaluated. In 68.7% of cases, the EDF was transiently restored (trAEDF group), in the rest of 31.2% remained persistent absent (prAEDF group). UA-PI significantly decreased in the first day after Dex (day 1/0;  The incidence of early-onset preeclampsia (ESP)  is generally estimated as being <1%  found a Steroids are typically used to improve fetal outcomes in expected preterm labor ,12. TheiThe current work is focused on the effect of maternal administration of dexamethasone (Dex) on fetal circulation in (severely) restricted fetuses, revealing AEDF in UA, exclusively from ESP pregnancies. Complementary, a correlation between the Doppler spectrum in UA and in the right and/or left uterine arteries (r/lUTAs) was also evaluated.This study was performed between January 2010 and June 2022 at the County Emergency Hospital of Craiova, Romania, the County Emergency Hospital of Constanta, Romania, and at “Timofei Mosneaga” Republican Clinical Hospital of Chisinau, Moldova. The three are tertiary care institutions. All cases belonged to the “normal” management category of the protocol of the facility, and no special or supplementary explorations were done. The patients were informed about the study design and agreed that all results for them and their newborns could be anonymized and used in the present study if the inclusion criteria were met.The inclusion criteria referred to singleton ESP pregnancies with ultrasound-certified fetal growth restriction (FGR) and AEDF in UA. No patient with fetal malformations was included. Fetuses with REDF in UA and/or absent or reversed A-wave in ductus venosus (DV), according to our institutional guidelines, underwent a rapid corticoid cure, if possible, and were delivered in the subsequent next 24–48 h. This is concordant with Karsdrop et al. , who fou3), impaired liver function , progressive renal insufficiency, new cerebral or visual disturbances, or epigastric or right upper quadrant pain [The diagnosis of ESP was established on generally accepted criteria. These included increased blood pressure occurring between 20 and 34 weeks of gestation in a previously non-hypertensive woman, with systolic value > 160 mmHg and diastolic value > 120 mmHg at one measurement, or >110 mmHg measured at least twice with an intervening 6-h rest and associated proteinuria, defined as >300 mg/day. In patients with no proteinuria in addition to hypertension, ESP was diagnosed based on one or several signs of severity. These signs included oliguria (<500 mL/24 h), thrombocytopenia  was considered to conform with the recommendation of the ISUOG Practice Guidelines: the fetal abdominal circumference (AC) below the 5th percentile of the normal range for gestation . SeverelAll patients received similar appropriate antihypertensive therapy. Magnesium sulfate was used to prevent seizures and for neonatal neuroprotection.For fetal therapy, Dex was administered according to our institutional guidelines for estimated preterm births. The Dex regimen consisted of four doses of 6 mg intramuscularly at 12-h intervals. Spectral Doppler of UA, middle cerebral artery (MCA), DV, and supplementary r/lUTAs-PIs, were performed at inclusion, before the first dose of Dex (day 0 or hour 0), and at 24, 48, 72, and 96 h after inclusion (days 1 to 4). Each fetus was transabdominal scanned by the same expert, with the fetus in quiescence and apnea. For each determination, at least 10 uniform wave spectra were recorded, and the pulsatility index (PI) was automatically calculated by the system.The normal ranges for UA-PI, MCA-PI, and cerebroplacental ratio (CPR) conformed to the Fetal Medicine Foundation charts , for DV-Data analyses were performed using SPSS Statistics 23 software (IBM). The procedures used included descriptive statistics, graphs, parametric statistical tests (one-way ANOVA test), and nonparametric statistical tests: chi-square test (OR) and Kruskal Wallis test, respectively. The significance level was 0.05, and the confidence interval (CI) was 95%.Initially, we included 37 singleton pregnancies fulfilling the criteria. All these fetuses were severely growth-restricted. Five patients that delivered (spontaneously or induced) in the first 48 h after the first dose of Dex were excluded since the interval was considered too short for evaluation and analysis.The mean age of the patients included was 22.1 ± 5.6 years (ranging from 15 to 41 years).Doppler examination of the UA revealed Dex transiently restored the EDF in the UA in 22 (68.7%) cases. These cases comprised the transiently restored (absent) end-diastolic flow group (trAEDF). The remaining 10 (31.2%) fetuses showed no variation and comprised the persistent absent end-diastolic flow group (prAEDF). The effect started in the first 24 h after the first dose of Dex and lasted up to day 4. f-ratio = 4.92624; p = 0.034). The GA was calculated according to the first day of the last menstrual period (GA(LMP)) and confirmed (when the results were available) by the data from the first-trimester ultrasound examination.The prAEDF group had a significantly lower gestational age (GA) at admission compared with the trAEDF group  but not in the prAEDF group (p = 0.055)  . p = 0.037).Until delivery, in total, five cases (50%) belonging to the prAEDF group and in three (13.6%) cases from the trAEDF group, respectively, the Doppler worsened, with the occurrence of REDF in UA and/or absent A-wave in DV, imposing fetal extraction. The difference was statistically significant . Dex transiently decreased the MCA-PI in both groups, with a maximal effect on day 1 and a gradual return to values prior to corticoid treatment by 3 and 4. This variation was statistically significant only in the trAEDF group (p = 0.030) but not in the prAEDF group (p = 0.227)  of fetuses in the prAEDF group and in 6/22 cases (27.2%) in the trAEDF group . The dif= 0.227) .CPR was subunitary in all fetuses at recruitment . CPR slightly increased from day 0 to day 2, followed by a gradual return to the initial value in the ensuing few days. The variation was significant in neither group . p = 0.211). The DV Doppler revealed a DV-PI above the 95th percentile in 9/10 (90.0%) cases from the prAEDF group and in 15/22 (68.1%) cases from the trAEDF groups . The difDV-PI decreased slightly on the first day after Dex administration and recovered during day 2. This variation was significant in none of the groups .At admission, the PI was above the 95th percentile in both UTAs in all patients. UTAs-PIs showed no significant variation during the 5 days of observation in both groups .There were no differences between either rUTA-PI or lUTA-PI in the two groups (tr/prAEDF groups) .Our institutional protocols recommend Dex in expected preterm birth. No difference in efficacy between this steroid and betamethasone efficiency has been evident, and the selection depends on the clinical experience of the physician ,29. HoweUA Doppler is the sole approach that offers both diagnostic and prognostic information for the management of FGR . DopplerIn the current study, the UA-PI exceeded the 95th percentile in all AEDF cases, with high UA-PI being an early sign of severely increased resistance in UA ,31.Dex transiently restored the end-diastolic flow in UA in 68.7% of cases, a rate concordant with the reports of Smichen et al.—55% , RobertsThe GA(LMP) was significantly lower in the prAEDF group compared with the trAEDF group because the maternal symptoms, such as: hypertension, headache, edema, abdominal pain, and visual disturbances, occurred earlier in gestation with an earlier diagnosis of EPS. The fact was probably, the result of more severe systemic abnormalities. Furthermore, these systemic abnormalities, possibly were the result of more defective placentation, with maternal impact but also with more severe fetal impact, revealed by UA non-response to Dex administration. This conclusion is concordant with the report of Moldenhauser et al. , who fou+-channels. So, it can be speculated a positive effect of dexamethasone on the expression of these channels, followed by vasodilatation.The mechanism of transiently restoring from absent (or reversed) to positive EDF in UA remains gloomy. It was proposed that steroids act through the placental corticotrophin-releasing hormone (CRH) dependent processes. Normally, steroids decrease the hypothalamic secretion of CRH but increase the placental production of the peptide . The pepThe lack of an effect of Dex in prAEDF fetuses was a good predictor for a significantly increased rate of proximal fetal deterioration (including worsening Doppler and/or occurrence of spontaneous decelerations) and for a poorer neonatal outcome, especially involving hypoxia and hypoxia-induced complications .p-value of 0.055 was close to the cutoff value of 0.05.Dex induced significant variation in UA-PI between days 1 and 0 and days 4 and 2 in both groups, but between days 4 and 1 only in the trAEDF group. It is likely that this last variation would have also been significant in the prAEDF group if this group comprised a larger cohort since the We found an almost two-fold increase in the incidence of MCA-PI below the 5th percentile in the prAEDF group, compared with the trAEDF group. The difference was not significant. However, CPR was subunitary in all AEDF fetuses. The latter finding provides further evidence that CPR is the main instrument to evaluate fetal cerebral redistribution, but the cutoff value of CPR for poor perinatal outcome prognosis has been variously reported ,44,45,46Dex decreased the MCA-PI during the first day after administration in both groups. This decrease was significant only in the trAEDF group. The difference was probably due to an already higher grade of vasodilatation in the fetal cerebral circulation in fetuses belonging to the prAEDF group. The mechanism of the steroid-induced MCA-PI reduction probably included cerebral involvement .The slight and non-significant increase in CPR during the first day after Dex was secondary to a more pronounced decrease in UA-PI, compared with MCA-PI, in the same period.DV-PI exceeded the 95th percentile in 90.0% of cases from the prAEDF group and 68.1% of cases from the trAEDF group, the difference being non-significant. These findings indicate that the severely increased resistivity in UA, with UA-PI > 95th percentile (which characterizes AEDF fetuses), preceded and triggered the increased blood shunt through DV, as revealed by the high DV-PI . The abnThe decrease in DV-PI on the first day after maternal administration of Dex was probably a consequence of the improvement in the UA flow induced by the steroid. However, the decrease was not statistically significant. UTAs-PIs were above the 95th percentile in all cases. This fact is concordant with the report of Sebire et al. , who remThe fact that the amplitude of both rUTA-PI and lUTA-PI were not different in trAEDF compared with the prAEDF group highlights the possibility that the defective placentation differently interests the placental-uterine interface versus the placental-umbilical interface.Furthermore, the UTAs-PIs were not affected by the corticoid, data concordant with the reports of Senat et al.  and EkinIn (severely) growth-restricted fetuses with AEDF in UA, from early-onset severe preeclamptic pregnancies, the fetal monitoring and delivery are based on a complex Doppler investigation, including UA, MCA, and DV.UA-PI > 95th percentile precedes and always accompanies all AEDF cases, being an earlier and a less severe sign of increased resistance in UA. Dex, administered for fetal lung maturation, transiently restores the end-diastolic flux in UA in the majority of cases and decreases the UA-PI, this effect lasting up to the 4th day. In all growth-restricted fetuses with AEDF in UA, from ESP pregnancies, the CPR is subunitary, as proof of already severely installed blood redistribution.Dex significantly decreased the MCA-PI during the first day after maternal administration in all fetuses. The decrease was significant only in the trAEDF group, probably as a consequence of more intense cerebral vasodilation in cases with persistent AEDF in UA.DV-PI > 95th percentile was noticed at similar rate, but not in all cases, in transiently restored and in persistent AEDF in UA fetuses, fact proving that it is a marker of high fetal distress, occurring later than severe abnormalities in UA. The DV Doppler is a very important marker for delivery timing. The no significant DV-PI’s transiently reduction (during the first day) is probably the result of an improvement in umbilical circulation after Dex administration.Increased velocities in UTAs (UTAs-PIs > 95th percentile) were noticed in all patients, but, despite the same etiology, uterine abnormalities only partially corroborate with the grade of umbilical artery distress.Dexamethasone has no impact on UTAs-PI.


Bone morphogenetic proteins (BMPs) are proteins of the transforming growth factor-β (TGF-β) family, which plays an important role in the formation of skeletal and cartilage tissue and their regeneration. BMPs play a key role in the formation of new blood vessels and promote the migration, proliferation, and differentiation of mesenchymal stem cells (MSCs) into chondroblasts and osteoblasts. It is known that malfunction of BMPs signaling can cause a disease state. Epigenetic regulation of expression plays a key role in the control of many cellular processes. Important participants in this regulation are non-coding RNAs (ncRNAs), which are RNA molecules that are not translated into proteins. The best known of these are microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). In addition, the results of many studies make it possible to establish an unambiguous functional relationship between these ncRNAs. Being involved in the regulation of a large number of target genes responsible for the life of the cell, miRNAs, lncRNAs, and circRNAs are essential for the normal development and functioning of the body, and the violation of their functions accompanies the development of many pathophysiological processes including oncogenesis. In the present review, we discuss different insights into the regulation of BMPs signaling pathway by miRNAs, lncRNAs and circRNAs governed. BMPs stimulate the formation of new blood vessels and promote migration, proliferation, and differentiation of mesenchymal stem cells (MSCs) into chondroblasts and osteoblasts. BMP-2, -4, -6, -7 and -9 have the most pronounced osteogenic properties ,2.BMPs activity is mediated by the activation of downstream extracellular signaling pathways, which in turn are initiated by BMPs binding to transmembrane receptor protein serine/threonine kinases (RSTK). This interaction triggers specific intracellular signaling pathways that control the transcription of specific target genes . There aNon-coding RNAs (ncRNAs) are a class of RNA molecules that are not translated into protein. Based on their length, ncRNAs can be divided into three categories: 1) ncRNAs longer than 200 nucleotides (nt), including long non-coding RNAs (lncRNAs); 2) ncRNAs shorter than 200 nt but longer than 40 nt, such as transfer RNA (tRNA) and small nucleolar RNA (snoRNA); and 3) ncRNA short than 40 nt like microRNAs (miRNAs) . Unlike 2MiRNAs are short, averaging 18–22 nucleotides, single-stranded nсRNAs that regulate gene expression at the post-transcriptional level by binding to the 3′-untranslated region (3′-UTR) of specific messenger RNA (mRNA) targets, resulting in a decrease in protein expression by blocking translation and (or) contributing to the degradation of mRNA targets ,11. TherBMPs signaling pathway cascades are post-transcriptionally modulated by different miRNAs that stimulate or inhibit osteogenesis, angiogenesis or neurogenesis. Specifically, several miRNAs can directly increase or reduce the expression of the genes coding for components of the BMPs signaling pathways or the transcription factors involved in cells differentiation, ultimately exerting both stimulatory and inhibitory effects on osteogenesis, angiogenesis or neurogenesis ,14.Osteoblast differentiation is a key step in skeletal development. Activation of the TGF-β and BMPs signaling pathways is involved in the differentiation of MSCs into the osteogenic lineage. For example, BMP-2 and BMP-7 act as potential differentiators through Smad-mediated activation of major osteoblast target genes such as Runx2 ,15. A nuIt is known that inactivation of the BMPs signaling pathway leads to the development of various vascular disorders ,24. For In addition to their well-characterized role in bone development, BMPs are critical to neurodevelopment . Mao et 3LncRNAs are non-coding transcripts over 200 nucleotides long, which are regulators of both physiological intracellular processes and intercellular interactions, and the pathogenesis of various human diseases. LncRNAs have been shown to play a critical role in transcription, imprinting and DNA methylation, translation, chromatin modification, and cell cycle regulation ,11. LncRin vivo and in vitro. The authors also found that inactivation HOTAIR can to inhibit bone generation and downregulate Runx-2 as well as osteocalcin (OCN), which could theoretically down-regulate the expression of osteopontin (OPN) and thus lead to further inactivation of HOTAIR. Thus, it is conceivable that OPN and HOTAIR could form a positive feedback loop in the regulation of MSCs osteogenesis. In other study, Su et al. demonstrated that HOTAIR regulates fracture healing in osteoporotic rats through inhibition on miR-17-5p [LncRNAs are known to function as competing endogenous RNAs, binding to miRNAs responses to effectively sequester miRNAs, thereby regulating biological processes such as osteogenesis . This feiR-17-5p . HOTAIR iR-17-5p . The disIn their study, Fu et al. showed that lncRNA PVT1 was highly expressed in human glioma tissues and cell lines . It has 4СircRNAs are type of single-stranded RNAs that, unlike linear RNA, forms a covalently closed continuous loop. In circRNA, the 3′ and 5′ ends normally present in an RNA molecule are joined together . This feOsteoporosis in its genesis is a multifactorial disease, in the formation of which a significant contribution is made by factors involved in the processes of bone remodeling and being target molecules for the search for new drugs . These iTo date, the mechanism of circRNAs in postmenopausal osteoporosis remains largely unknown. However, there are a number of evidence-based studies on the role of circRNAs in the pathogenesis of postmenopausal osteoporosis. For instance, Qiao et al. elucidated that circRNA_0048211 was downregulated in human BMSCs were collected from progression of postmenopausal osteoporosis patients, which was gradually enhanced during osteogenesis . Overexp5Due to the rapid development of sequencing technologies and bioinformatics approaches in recent decades, various classes of ncRNAs have been discovered, including miRNAs, lncRNAs, and circRNAs. It is known that ncRNAs play an important biological role in the regulation of cellular mechanisms in both physiological and pathophysiological processes. NcRNAs can interact with and regulate various types of molecules through various molecular mechanisms, creating a complex regulatory network. NcRNA-mediated networks not only contain interactions between RNAs, but are also involved in genomics and proteomics in both the nucleus and cytoplasm.Osteogenesis, angiogenesis and neurogenesis are complex processes involving several transcription factors and proteins. Moreover, a number of signaling cascades, particularly BMPs signal pathways regulate this process. Runx2 and osterix signaling cascades are other cascades that are involved in this processes. NcRNAs play an important role in the regulation of these transcription factors and signaling cascades in both health and disease. Experiments on various types of MSCs confirmed the importance of miRNAs, lncRNAs, and circRNAs in the regulation of the osteogenic process in these cells. These observations are of practical importance in medicine, especially in the treatment of bone diseases such as osteoporosis.MiRNAs involved in oncogenesis mainly regulate the activity of Wnt, Notch, PI3Ks/AKT/mTOR, and BMPs signaling pathways. LncRNAs and circRNAs can directly influence the expression of these signaling pathways or oncogenic transcription factors. Moreover, they can serve as a molecular sponge for miRNAs. MALAT1/miR-494/BMP-2, MALAT1/miR142-3p/BMP-7, TUG1/miR-214/BMP-2, mm9_circ_009056/miR-22-3p/BMP-7, and hsa_circ_0005752/miR-496/BMP-2 are examples of such kind of interaction between miRNAs, lncRNAs and circRNAs by regulate BMPs signaling pathways in the context of biological processes and pathological conditions.Briefly, several miRNAs, lncRNAs, and circRNAs have been found to alter the expression of BMPs signaling pathways, thus being involved in both normal physiological processes and oncogenesis or pathogenesis of bone disease.None.Conceptualization, Writing - original draft and Project administration: Ilgiz Gareev; Writing - review and editing, Investigation and Resources: Ural Mukhametov; Formal analysis and Methodology: Sergey Lyulin and Alina Shumadalova; Data curation: Sergey Lyulin, Dmitry Borzunov and Galina Sufianova; Validation and Visualization and Funding acquisition: Ural Mukhametov; Supervision: Sergey Lyulin. All authors have read and agreed to the published version of the manuscript.The authors declare no conflict of interest, financial or otherwise.


Diffuse large B-cell lymphoma (DLBCL) encompasses a wide variety of disease states that have to date been subgrouped and characterized based on immunohistochemical methods, which provide limited prognostic value to clinicians and no alteration in treatment regimen. The addition of rituximab to CHOP therapy was the last leap forward in terms of treatment, but regimens currently follow a standardized course when disease becomes refractory with no individualization based on genotype. Research groups are tentatively proposing new strategies for categorizing DLBCL based on genetic abnormalities that are frequently found together to better predict disease course following dysregulation of specific pathways and to deliver targeted treatment. Novel algorithms in combination with next-generation sequencing techniques have identified between 4 and 7 subgroups of DLBCL, depending on the research team, with potentially significant and actionable genetic alterations. Various drugs aimed at pathways including BCR signaling, NF-κB dysfunction, and epigenetic regulation have shown promise in their respective groups and may show initial utility as second or third line therapies to patients with recurrent DLBCL. Implementation of subgroups will allow collection of necessary data to determine which groups are significant, which treatments may be indicated, and will provide better insight to clinicians and patients on specific disease course. Diffuse large B-cell lymphoma (referred to as DLBCL) is characterized by a consistent range of cellular precursors and nuclear morphology, namely large B lymphoid cells with nuclei exceeding normal lymphocyte size, but spans many immunologic and genetic subtypes without much further classification . ImmunohMYD88L265P and CD79B mutations, which are also defining characteristics of MCD/C5 genetic subgroups, which are to be expanded upon further in this review.The International Consensus Classification of Mature Lymphoid Neoplasms, which aims to provide standardized diagnostic criteria for lymphoid malignancies to pathologists, geneticists, scientists, and clinicians recognizes the utility of cell-of-origin (COO) designation in DLBCL, but also acknowledges that the system has shortcomings . StratifThe fifth edition of the World Health Organization Classification of Haematolymphoid Tumours: Lymphoid Neoplasms (WHO-HAEM5) exists to provide global definitions and classification systems for lymphoid tumors, and is intended for use by pathologists, clinicians, and research scientists . CharactNational Comprehensive Cancer Network (NCCN) guidelines direct practitioners to standardized R-CHOP therapy  as first line treatment regardless of presentation or cellular markers, and refractory cases are treated uniformly with further R-CHOP therapy at higher dosage, second line therapy in combination with hematopoietic cell transplant, chimeric antigen receptor T-cell (CAR T-cell) therapy, clinical trials, or finally palliative care . The secIdentification of genetic markers that alter disease course is essential not only for implementation of effective treatment, but also to indicate which patients may require less potent treatment or less invasive surveillance in looking for relapse. New therapies derived from NGS provided data are aimed at disrupting signaling pathways or modulating immune response, however the impact of these therapies can only be fully realized when we are able to categorize DLBCL into subtypes based on internal disease mechanism, as opposed to outward morphology or presence of basic cell markers. These internal mechanisms, and sorting the influential from the irrelevant, are the basis for future treatment modalities and the cessation of indiscriminate therapy based on patient response. In this paper we will begin by exploring the various diagnostic criteria for subtyping of DLBCL on a molecular level, and the genetic alterations that change basic signaling pathways and cascades that determine disease progression and outcome. Targeted therapies aimed at these pathways will be investigated, and lastly the clinical implications and research still needed will be discussed.DLBCL can currently be divided into 3 subtypes based on cell of origin (COO), ABC, GCB, and Unclassified, which yield moderate prognostic value and decidedly limited clinical value due to the standard progression of treatment regimens across all three types . These sNGS has allowed for the analysis of extremely large DLBCL samples in order to differentiate impactful pathogenetic sequences from those that do not significantly alter disease course, as well as provide a meaningful way of typing cells more accurately than the current standard (ABC/GCB grouping based off variable immunochemistry) . A studyABC, GCB, and Unclassified DLBCL are divided based on stage of development they most resemble after some genetic mutation disrupts typical progression and causes malignant transformation. The cells of these subtypes develop their morphologic and clinical characteristics based on the stage of development in which they accumulate enough genetic variation to become malignant, and differentiation either ceases or continues on a path not seen by healthy and functional B cells . The ABCPRDM1 truncations or homozygous deletions only seen in the ABC subtype, that have given insight into their behavior patterns  translocations leading to BCL2 activation and overexpression, and CREBBP mutation affecting the histone acetyltransferase domain leading to epigenetic dysregulation  inhibitor, supporting the notion that better characterization of genetic phenomena and heterogeneity can lead to more effective and targeted treatment  overlap heavily with the genes observed in the Schmitz et al. subgroup MCD, where extranodal involvement was also noted to be significant  that divides DLBCL cells into C1, C2, C3, C4, or C5 depending on pattern of gene expression with defining genetic drivers, or C0 if a genetic driver could not be identified . Clusternificant . While tnificant . C3 whicpe DLBCL . These spe DLBCL . This isll cycle . Clusterll cycle .MYD88 mutation among others and contained the majority of observed primary CNS lymphomas and primary testicular lymphomas, similarly to MCD and C5 groups , but are dependent on each other for the survival of the cell inextricably linking the altered pathways.Another key classification system using an algorithm referred to as “LymphGen” developed by ll death . A sort Understanding which genetic anomalies tend to occur together and the associated prognosis is an essential primary step in establishing a new categorization system for DLBCL, but is far from the end product. To develop effective treatments we must thoroughly understand the pathways that have undergone alteration, and establish whether or not they are even influential in overall disease progression. Equally important is establishing where in a specific pathway the disruption occurs, because mutations downstream of drug targets may render the drug useless, even if it acts on the appropriate pathway. By taking a closer look at which pathways tend to undergo alteration and where alterations tend to take place, we will establish not only the extreme complexity of DLBCL, but can begin to identify potential drug targets for later discussion of therapeutic indications.Until now we have discussed pathways that have been identified as influential in disease state and developing criteria for new subtypes. We will now take a closer look at some of the most commonly mutated pathways, including BCR signaling, PI3K-AKT-mTOR signaling, BCR dependent NF-κB activation, NF-κB signaling, TLR signaling, and the BCL2 anti-apoptotic family . These pCD79B which is detected in near 20% of ABC DLBCL cases  which is of potential clinical utility because aggressive lymphomas with MYD88L265P and CD79B mutations have a response to ibrutinib (Bruton’s tyrosine kinase is downstream of BCR) and presumably have chronic active BCR signaling  are identified in 6% of ABC DLBCL but not GCB, others (PTEN deletion) are present in both ABC and GCB (9%–11%)  .BCL2L1, BCL2A1, RELB, BIRC3, and BCL3   that inactivates negative regulator CYLD/SPATA2 complex and inactivates RELB . ZC3H12Aand BCL3 . Inactivagenesis . Failureagenesis . Mutatio pathway . CARD11 of NF-κB . Inactivof NF-κB . Inactivof NF-κB . Negativof NF-κB . 66.2% oA (mRNA) . In the A (mRNA) . SignatuA (mRNA) .TLR2 and MYD88, or inactivation of negative regulators TNIP1/TNFAIP3, result in the ability of IκB kinase (IKBKG/IKBKB) to inhibit the NFKBIA/NFKBIE complex  signaling in its standard state is mediated by MYD88, an adapter protein which assists in signaling, in complex with IRAK1/4 . Mutatio pathway . ActivatR ligand . Activatpathways . Inactivpathways .BCL2 mutations occur and are noted in various DLBCL subtypes, such as the t translocation seen in 34%–44% of GCB DLBCL  in 38% of EZB type cases. BCL6 signaling disruption is also found in commonly in EZB subtype. BN2 type . EvasionNOTCH1 and NOTCH2) code for a series of receptors involved in specialization of cells, cell growth, differentiation, and apoptosis  or inactivating mutations of BCL6 inhibitors  lead to suppression of these processes previously mentioned, and promotion of germinal center formation and disruption of plasma cell formation  normally inhibits MDM2, preventing inactivation of p53 by MDM2, but p14ARF can develop an inactivating mutation leading to constitutive inhibition of p53 by MDM2 (MDM2 or MDM4 (another inhibitor of p53) can also lead to continued inactivation of p53, and failure of CDKN1A/BAX mRNA transcription  suggesting the possible targetability of this pathway , which normally is responsible for somatic hypermutation and class switch recombination, but can also target and create breaks in BCL6 and MYC  are also implicated in improper MYC expression  cause loss of this extracellular ligand and subsequent failure of NK-mediated cytolysis  gains, amplifications, and translocations are another mechanism by which DLBCL evades destruction by T cells, because binding of this ligand to PD-1 receptors on CD8+/CD4+ T cells prevents activation . Enzastaurin is a selective PKCβ inhibitor which would inhibit signal transduction and ultimate pathway activation, but efficacy has yet to be shown with this drug, and clinical failures have been attributed to mutations further down the pathway than at PKCβ . This drerations . MYD subrvention . One sturvention .TSC1 and NF2, which were deemed significant to the dramatic efficacy of this drug  and HDAC (class I and II), that showed a response rate of 64% in patients with DLBCL concurrent with MYC alteration . Other dhis drug . Anotherhis drug . Furtherhis drug .MYD88 mutations promote NF-κB signaling, encouraging cell proliferation and survival, while also promoting the production of interferon-beta (IFNβ) which is cytotoxic to DLBCL cells  interfere with BET-mediated MYC transcription through disruption of bromodomain-containing proteins which normally organize transcriptional machinery (MYC among other oncogenes (The ability to block overactive ry DLBCL . The broachinery . Birabrencogenes . The supncogenes .CD274) and PD-L2 (PDCD1LG2) dysregulation is one of the most notable from a therapeutic standpoint. This pathway is targetable by antibodies that bind and block the PD-L1/2 ligand on the tumor cell, preventing it from binding PD-1/2 receptor and disabling immune escape (CD274/PDCD1LG2) low level copy gains and amplifications  and primary testicular DLBCL (60%) and further emphasizes the importance of these PD-1 ligands in predicting PD-1 antibody treatment success (Evasion of DLBCL immune surveillance is accomplished through various mechanisms, but PD-L1 (e escape . One suce escape . Failureications . An alteutations . These rtibodies . A thirdtibodies . The suc success .EZH2, KMT2D, EP300, and CREBBP may also result in aberrant pathway activation or inactivation in many DLBCL cases, so exploring treatments directed at regulation of these pathways may also prove to be impactful on outcomes. Other pathways of interest with potential therapeutic interventions are the NOTCH signaling pathway, malignant cell migration resulting from S1PR2 inactivation, BCL6 signaling, p53 signaling, MYC signaling, and immune evasion through mutations in various receptors and ligands such as PD-L1 overexpression. Therapies currently showing promise include ibrutinib in targeting BCR signaling, everolimus in the PI3K-AKT-mTOR pathway, lenalidomide in targeting NF-κB signaling, venetoclax in BCL2 signaling, tazemetostat in EZH2 epigenetic regulation, birabresib in targeting MYC signaling, and nivolumab in targeting immune evasion.DLBCL encompasses a wide array of disease mechanisms and presentations that have historically been and are currently, lumped into essentially two prognostic groups all with the same therapeutic indication. Various novel ways to delineate cases of DLBCL have been proposed by groups such as In order to progress in the treatment of DLBCL, a new classification system must first be implemented as part of NCCN guidelines that will allow physicians to provide better prognostic information, and which may also indicate which second line therapies may have superior response when first line R-CHOP fails. Availability of NGS for use in patients with DLBCL will also need to be increased, as these groupings rely on this in combination with novel algorithms to appropriately place a malignancy in its respective group. Implementation of these groups will also greatly supplement data concerning tracking of disease course by group and response to therapies, because currently the population of DLBCL that has had their disease subtyped or genomically sequenced is relatively low and limited to experimental groups. With larger quantities of data we will be able to further differentiate which mutations are impactful on disease course, and which mutations may indicate a specific or targeted treatment. This will also allow us to increase the specificity of the subgroups and establish a more concrete stratification system. There is little doubt that a newly implemented subtyping system for DLBCL will need revision over time as data is collected, and the standard of care R-CHOP therapy will not be replaced overnight. Currently implementation of these groups will provide us with much needed and much lacking data and will give providers and patients the ability to supplement second- or third-line therapies with regimens targeted to their specific subtype or mutation which has never previously been done. Providing one more therapeutic option before making the move to palliative care is enough justification alone to support the use of new groups and targeted therapies and is step-one on the road to creating a new standard of care for these patients.


Uric acid was found to have a positive correlation with thyroid nodules in the cross-sectional studies recently. We aimed to conduct a retrospective cohort study to investigate whether uric acid is a risk factor for the development of thyroid nodules.We reviewed the data of individuals who attended the medical check-ups in our hospital from 2010 to 2019. A total of 6587 adults without thyroid nodules at baseline were enrolled in this study. Logistic regression with or without restricted cubic spline function was used to investigate the non-linear or linear association between uric acid and thyroid nodules, respectively.P = 0.028) with the development of thyroid nodules, but the association was not non-linear (P = 0.516). The results indicate that the association between them is linear, which was demonstrated by a logistic regression model, in which the odds ratio of uric acid per 100 mmol/L was 1.137 (P = 0.004). Age, sex, diastolic blood pressure, fasting blood sugar, and blood monocyte were found to be risk factors for thyroid nodules as well.Baseline characteristics showed that subjects mainly consisted of the healthy, young population. After fully adjusting for the potential confounders, such as age, sex, metabolic and inflammatory indicators, hepatic and renal function, a logistic restricted cubic spline regression model suggested that uric acid had a significant association (Uric acid is an independent risk factor for the formation of thyroid nodules. This finding warrants attention to this risk factor in apparently healthy adults. Thyroid diseases nowadays have become common diseases in clinical practice. Graves’ disease and thyroiditis, both of which tend to have explicit symptoms, are easily detected and diagnosed. Thyroid nodules (TNs) of huge size will oppress the ambient tissue and cause a symptom, which will be identified easily as well. However, most TNs are asymptomatic and incidentally found in a routine medical checkup by palpation or ultrasound . It is rUric acid (UA) is the end product of purine catabolism, which is present mostly in the liver, intestines, muscles, and the vascular endothelium. Although UA plays an important biological role as an antioxidant, high levels of UA are associated with many metabolic and non-metabolic diseases. The direct impairment of high UA comes from gout, but it has also been linked with other metabolic disorders, such as insulin resistance, hypertension, and diabetes .There is a close link between metabolic disorders and TNs. A study investigated Chinese people living in a moderate iodine intake area and found that people with metabolic syndrome have higher morbidity of TNs than those without. After correction for the possible confounders, logistic regression showed that waist circumference, high blood pressure, and fasting blood glucose are positively and independently associated with TNs . In a miWe respectively collected the data of the subjects who attended health check-ups in our department in the First Affiliated Hospital of Shantou University Medical College from January 2010 to December 2019. We didn’t collect the data before 2010 or after 2019 because a few of the analyzers were upgraded at these two time points. Subjects resided in a coastal city that has implemented the salt iodization policy since 1993. Seafood products, which contain abundant iodine, accounted for a large part of their diet. Thus, subjects were considered to be iodine-adequate. In our department, clients with severe diseases or clinical symptoms were led to the emergency or outpatient department. Thus, subjects were considered to be healthy or mildly ill. The inclusion criteria were: (1) subjects who have two or more health check-up records; (2) have comprehensive examinations including UA and other metabolism-related indicators, complete blood count, hepatic function, renal function, and thyroid ultrasound. The exclusion criteria were: (1) subjects with thyroid nodules; (2) with a history of thyroid surgery; (3) with suspicious Graves’ disease and thyroiditis identified by thyroid ultrasound; (4) with missing data or outliers. There were 9718 subjects were enrolled in this study according to the inclusion criteria. After exclusion, 6587 TN-free subjects remained for further analysis.In our department, individuals were required to be barefooted and least dressed when measuring their body height and weight and were demanded to rest for at least 5—10 min before the blood pressure measurement. For the venous blood obtainment, individuals had to keep fasting from 10 p.m. the night before, and blood was drawn by the laboratorian the next morning (7:30–9:30 a.m.). A complete blood automatic analyzer  was used to test the complete blood count. A biochemical automatic analyzer  was used to test the hepatic, renal, and metabolic parameters. The thyroid ultrasound was performed with a high-frequency probe by the experienced sonographers. Besides ultrasonic reports, the data we collected included age, sex, metabolic and inflammatory parameters, and hepatic and renal function, all of which were found to be associated with TNs –17. Meta2). TN disease was defined as any solid and nodular lesion, which was detected by ultrasound to be different from the adjoining parenchyma in the thyroid gland [This is a retrospective cohort study. Each enrolled subject had at least two records of health check-up. The first record was collected as the baseline, and the last one was collected for the observation of the development of TNs. A period between the first and last records was defined as follow-up time. The body mass index (BMI) was defined as weight divided by the square of height was used for data analysis. In the analysis of the baseline characteristics, continuous data were presented as median  due to the non-normal distribution, and dichotomous data were presented as number (percentage). Normal distribution of the Continuous data was estimated by Kolmogorov–Smirnov test. Logistic restricted cubic spline (RCS) regression was used to investigate the non-linear association of UA with TNs. To fit a better RCS model, we explore RCS models with knot number from three to seven and chose a model with the lowest Akaike information criteria (AIC). Except for the non-linear association, as sensitivity analysis, we used logistic regression to detect the linear association of UA with TNs as well. In both non-linear and linear models, confounders included were age, sex, body mass index, systolic blood pressure, diastolic blood pressure, uric acid, fasting blood sugar, triglyceride, cholesterol, low-density lipoprotein, high-density lipoprotein, white blood cell, neutrophil, lymphocyte, monocyte, alanine transaminase, aspartate aminotransferase, total bilirubin, and creatinine. Follow-up time, the interval between the baseline and observation time, was different among subjects, a potential confounder, and adjusted as well. The baseline characteristics of the subjects were presented in Table P = 0.028). The P for non-linear association is the insignificance of 0.516, indicating a linear association between UA and TNs. Besides, from Fig. P = 0.692) between sex and UA was detected.The median follow-up time was 37.3 IQR: 14.5, 61.8) months, and 1345 subjects developed TNs at the observation time, with an incidence rate of 114 per 1000 inhabitants per year. We used logistic regression with UA per 100 mmol/L as a restricted cubic spline (RCS) variable to explore the non-linear association of UA with TNs. To fit a better RCS model, we explore RCS models with knot number from three to seven, and the model with 3 knots had the lowest AIC of 5945 was chosen. As Fig. 4.5, 61.8P = 0.004). Other risk factors found in this model were similar to those in the RCS model, such as age , female , diastolic blood pressure , fasting blood sugar , monocyte count   in northwest China. After adjusting for BMI, SBP, TC, TG, and FBS, serum UA appeared to be negatively associated with TNs in males over 30 years old, but positively associated with TNs in both males under 30 years old and females over 30 years old . In our Although the cross-sectional analysis showed the independent and positive relation between UA and TNs, we still cannot determine the cause-effect relationship between UA and the formation of TNs. We carried out a retrospective cohort study and found that a higher UA in baseline will increase the risk to develop a TN disease in the future. No previous evidence has demonstrated UA can promote TNs formation or the growth of thyroid cells. There is a possible explanation that might interpret this result. A study supplied evidence of UA directly inducing insulin resistance (IR) in vivo and in vitro. Increased UA levels may affect insulin receptor substrate 1 and protein kinase B, both of which are import links of insulin signaling, to induce IR. Besides, the reactive oxygen species pathway is also involved in the process of UA-inducing IR . AnotherHigh levels of TSH result in the presence of TNs. Because TSH stimulates TSH receptors/cAMP/PKA pathways in thyroid cells, thereby activating CREB and controlling thyroid cell differentiation and proliferation . NeverthEpidemiological studies have found that thyroid nodules are more prevalent as people age , 26. WitAlthough we have demonstrated the positive association between UA and TNs after adjusting a wide range of potential confounders, there are limitations to this study due to its retrospective format. Some potential confounders, such as comorbidities and genetic information, were not collected. However, the advantage of this study is that it is first demonstrated UA is a risk factor for the formation of TNs. The results need a further demonstration by a prospective design, accounting for more bias and confounders.UA is an independent risk factor for the development of TNs. Active intervention may benefit patients with high UA in terms of the prevention of TNs.


Insects are traditionally thought to respond to noxious stimuli in an inflexible manner, without the ability to modulate their behavior according to context. We investigated whether bumblebees’ attraction to high sucrose solution concentrations reduces their avoidance of noxious heat. Bees were given the choice between either unheated or noxiously heated (55 °C) feeders with different sucrose concentrations and marked by different colors. Bees avoided noxious feeders when the unheated feeders contained high sucrose concentrations, but progressively increased feeding from noxious feeders when the sucrose concentration at unheated feeders decreased. This shows a motivational trade-off of nociceptive responses. Bees used learned color cues for their decisions, and thus the trade-off was based on processing in the brain, rather than just peripheral processing. Therefore, bees can use contextual information to modulate nociceptive behavior. This ability is consistent with a capacity for pain experiences in insects. Bombus terrestris), is capable of context-dependent, centrally controlled reduction of nocifensive behavior.Nociception and nocifensive behavior—the detection of and response to noxious stimuli—occur across many animal taxa, including insects  and two alternative feeders. In the latter, different groups of bees were offered 10%, 20%, 30%, or 40% sucrose solution . Each grz = −13.12, P < 0.001, n = 41)    when alternative feeders contained lower sucrose concentrations . This reduction in landing but not feeding events between the first and final bout indicates that bees learned to use color/spatial cues, rather than landing on every feeder and sensing the sucrose/heat directly.We also recorded the number of “landing but not feeding” episodes on all feeders in the first and final foraging bouts. Unscented sucrose solution concentration cannot be detected unless the bee tasted the solution . The meaBumblebees avoided noxiously heated feeders less when these dispensed higher sucrose concentrations than unheated feeders. Unlike trade-offs described in other invertebrates , 6, 9, t12Forty-one forager bees from eight colonies were tested. Bumblebee nests  were kept in boxes connected to the testing arena, which contained four feeders . Each feSI Appendix). Before testing, a forager bee was chosen and only that bee was let into the arena. The bee was allowed to feed from the four feeders, which each contained 20 μL of sucrose solution. Sucrose solution concentrations were calculated weight per weight (wt/wt).The bees first underwent training to familiarize them with the feeder contents . Feeders were refilled every time the bee emptied them and landed on another feeder. Each bee completed 5 to 10 bouts (nest–arena–nest cycle) until it stopped foraging (no attempt to re-enter the arena for over 20 min). After a 45-min break to allow heat-pads to heat up, the bees entered the second testing stage (the heated temperature condition), where two of the high-quality feeders were heated to 55 °C (temperature was recorded using an infrared camera and infrared thermometer). The same testing protocol was followed.SI Appendix). All study materials, protocols, and methods are included in the main text and SI Appendix.Arena and feeders were cleaned with 70% ethanol every three bouts, as well as during the 45-min break. We recorded the number of feeding events, defined as “proboscis extended and contacting the sucrose-dispensing part of the feeder for more than 3 s,” and landing events, defined as “enters cardboard chamber of the feeder and does not feed,” using an iPhone 6s (Apple). For each bee, we calculated the mean proportion  across all her foraging bouts for each temperature condition. We also calculated the total number of landing events per first and final foraging bouts for each bee. We analyzed the data in R , using gSupplementary File