Takeda G Protein-coupled Receptor 5 Research Articles

Lactobacillus reuteri JCM 1112 ameliorates chronic acrylamide-induced glucose metabolism disorder via the bile acid-TGR5-GLP-1 axis and modulates intestinal oxidative stress in mice.

Acrylamide (AA) is a toxic food contaminant that has been reported to cause glucose metabolism disorders (GMD) at high doses. However, it is unclear whether chronic low-dose AA can induce GMD and whether probiotics can alleviate AA-induced GMD. Here, C57BL/6N mice were orally administered with 5 mg per kg bw AA for 10 weeks, followed by another 3 weeks of glucagon-like peptide-1 (GLP-1) analogue (dulaglutide) treatment. Chronic low-dose AA exposure increased the blood glucose level and decreased serum insulin and GLP-1 levels, whereas dulaglutide treatment decreased the blood glucose level and increased the serum insulin level in AA-exposed mice. Then, mice were administered with AA or AA + INT-777 (Takeda G-protein-coupled receptor 5 (TGR5) agonist) for 10 weeks. INT-777 treatment reversed AA-induced downregulation of ileal TGR5 and proglucagon (PG) gene expression and decreased the serum GLP-1 level. These findings indicated that chronic low-dose AA induced GMD via inhibiting the TGR5-GLP-1 axis. Finally, mice were administered with AA for 10 weeks, followed by another 3 weeks of Lactobacillus reuteri JCM 1112 supplementation. L. reuteri supplementation significantly increased serum glucose, insulin and GLP-1 levels, upregulated ileal TGR5 and PG gene expression, and effectively restored the imbalance of bile acid (BA) metabolism in AA-exposed mice, demonstrating that L. reuteri ameliorates chronic AA-induced GMD via the BA-TGR5-GLP-1 axis. In addition, L. reuteri significantly enhanced ileal superoxide dismutase and catalase activities and total antioxidant capacity, thereby preventing chronic AA-induced oxidative stress. Our research provides new insights into the GMD toxicity of chronic low-dose AA and confirms the role of probiotics in alleviating AA-induced GMD.

Inhibition of fatty acid uptake by TGR5 prevents diabetic cardiomyopathy.

Diabetic cardiomyopathy is characterized by myocardial lipid accumulation and cardiac dysfunction. Bile acid metabolism is known to play a crucial role in cardiovascular and metabolic diseases. Takeda G-protein-coupled receptor 5 (TGR5), a major bile acid receptor, has been implicated in metabolic regulation and myocardial protection. However, the precise involvement of the bile acid-TGR5 pathway in maintaining cardiometabolic homeostasis remains unclear. Here we show decreased plasma bile acid levels in both male and female participants with diabetic myocardial injury. Additionally, we observe increased myocardial lipid accumulation and cardiac dysfunction in cardiomyocyte-specific TGR5-deleted mice (both male and female) subjected to a high-fat diet and streptozotocin treatment or bred on the diabetic db/db genetic background. Further investigation reveals that TGR5 deletion enhances cardiac fatty acid uptake, resulting in lipid accumulation. Mechanistically, TGR5 deletion promotes localization of CD36 on the plasma membrane through the upregulation of CD36 palmitoylation mediated by the palmitoyl acyltransferase DHHC4. Our findings indicate that the TGR5-DHHC4 pathway regulates cardiac fatty acid uptake, which highlights the therapeutic potential of targeting TGR5 in the management of diabetic cardiomyopathy.

The Effect of Coenzyme Q10 Supplementation on Bile Acid Metabolism: Insights from Network Pharmacology, Molecular Docking, and Experimental Validation.

Bile acids play a crucial role in lipid absorption and the regulation of lipid, glucose, and energy homeostasis. Coenzyme Q10 (CoQ10), a lipophilic antioxidant, has been recognized for its positive effects on obesity and related glycolipid metabolic disorders. However, the relationship between CoQ10 and bile acids has not yet been evaluated. This study assesses the impact of CoQ10 treatment on bile acid metabolism in mice on a high-fat diet using Ultra-Performance Liquid Chromatography-tandem Mass Spectrometry. CoQ10 reverses the reduction in serum and colonic total bile acid levels and alters the bile acid profile in mice that are caused by a high-fat diet. Seventeen potential targets of CoQ10 in bile acid metabolism are identified by network pharmacology, with six being central to the mechanism. Molecular docking shows a high binding affinity of CoQ10 to five of these key targets. Further analyses indicate that farnesoid X (FXR) receptor and Takeda G-protein coupled receptor 5 (TGR5) may be crucial targets for CoQ10 to regulate bile acid metabolism and exert beneficial effects. This study sheds light on the impact of CoQ10 in bile acids metabolism and offers a new perspective on the application of CoQ10 in metabolic health.

The bile-gut axis and metabolic consequences of cholecystectomy.

Cholelithiasis and cholecystitis affect individuals of all ages and are often treated by surgical removal of the gallbladder (cholecystectomy), which is considered a safe, low-risk procedure. Nevertheless, recent findings show that bile and its regulated storage and excretion may have important metabolic effects and that cholecystectomy is associated with several metabolic diseases postoperatively. Bile acids have long been known as emulsifiers essential to the assimilation of lipids and absorption of lipid-soluble vitamins, but more recently, they have also been reported to act as metabolic signaling agents. The nuclear receptor, farnesoid X receptor (FXR), and the G protein-coupled membrane receptor, Takeda G protein-coupled receptor 5 (TGR5), are specific to bile acids. Through activation of these receptors, bile acids control numerous metabolic functions. Cholecystectomy affects the storage and excretion of bile acids, which in turn may influence the activation of FXR and TGR5 and their effects on metabolism including processes leading to metabolic conditions such as metabolic dysfunction-associated steatotic liver disease and metabolic syndrome. Here, with the aim of elucidating mechanisms behind cholecystectomy-associated dysmetabolism, we review studies potentially linking cholecystectomy and bile acid-mediated metabolic effects and discuss possible pathophysiological mechanisms behind cholecystectomy-associated dysmetabolism.

Targeted metabolomics revealed the mechanisms underlying the role of Liansu capsule in ameliorating functional dyspepsia

Ethnopharmacological relevanceLiansu capsule could alleviate dyspeptic symptoms; however, the mechanisms underlying its role in treating functional dyspepsia (FD) remain unclear. Aim of the studyTo elucidate the mechanism underlying the efficacy of Liansu capsule in alleviating FD symptoms. Materials and methodsThirty-six male mice were randomly divided into the following six groups: control, model, low-strength Liansu, moderate-strength Liansu, high-strength Liansu, and domperidone groups. Small intestine propulsion rate, gastric residual rate and histopathological analysis were performed to evaluate efficacy of Liansu capsule. Levels of interleukin-1β, interleukin-6, tumor necrosis factor α, phosphorylation of p65, ghrelin and gastrin were verified by real-time quantitative polymerase chain reaction and immunofluorescence assays. Targeted metabolomic analyses, western blotting and immunofluorescence assays were used to explore the mechanism of Liansu capsule in ameliorating FD. ResultsThe Liansu capsule significantly ameliorated the symptoms of FD, and markedly increased the levels of ghrelin and gastrin. Moreover, Liansu capsule significantly downregulated the levels of the proinflammatory cytokine interleukin-1β, interleukin-6, tumor necrosis factor α, and inhibited the phosphorylation of p65. Targeted metabolomic analyses showed that Liansu capsule significantly reduced the levels of deoxycholic acid and hyodeoxycholic acid, which were significantly elevated in the model group. Furthermore, these results showed that deoxycholic acid and hyodeoxycholic acid markedly promoted the levels of Takeda G-protein-coupled receptor 5 (TGR5), phosphorylated signal transducer and activator of transcription 3 (STAT3), and Kruppel-like factor 5 (KLF5) in vitro. whereas, Liansu capsule significantly reduced the levels of TGR5, phosphorylated STAT3, and KLF5. ConclusionOur findings indicated that Liansu capsule improved FD by regulating the deoxycholic acid/hyodeoxycholic acid-TGR5-STAT3-KLF5 axis. The findings reveal a novel mechanism underlying the role of Liansu capsule, which may be a promising therapeutic strategy for FD.

The role of bile acid receptor TGR5 in regulating inflammatory signalling.

Takeda G protein-coupled receptor 5 (TGR5) is a bile acid receptor, and its role in regulating metabolism after binding with bile acids has been established. Since the immune response depends on metabolism to provide biomolecules and energy to cope with challenging conditions, emerging evidence reveals the regulatory effects of TGR5 on the immune response. An in-depth understanding of the effect of TGR5 on immune regulation can help us disentangle the interaction of metabolism and immune response, accelerating the development of TGR5 as a therapeutic target. Herein, we reviewed more than 200 articles published in the last 20 years in PubMed, to discuss the roles of TGR5 in regulating inflammatory response, the molecular mechanism, as well as existing problems. Particularly, its anti-inflammation effect is emphasized.

Bile salt signaling and bile salt-based therapies in cardiometabolic disease.

Bile salts have an established role in the emulsification and intestinal absorption of dietary lipids, and their homeostasis is tightly controlled by various transporters and regulators in the enterohepatic circulation. Notably, emerging evidence points toward bile salts as major modulators of cardiometabolic disease (CMD), an umbrella disease of disorders affecting the heart and blood vessels that is caused by systemic metabolic diseases such as Type 2 diabetes mellitus (T2DM) and metabolic dysfunction-associated steatotic liver disease (MASLD), the latter encompassing also metabolic dysfunction-associated steatohepatitis (MASH). The underlying mechanisms of protective effects of bile salts are their hormonal properties, enabling them to exert versatile metabolic effects by activating various bile salt-responsive signaling receptors with the nuclear farnesoid X receptor (FXR) and the Takeda G-protein-coupled receptor 5 (TGR5) as most extensively investigated. Activation of FXR and TGR5 is involved in the regulation of glucose, lipid and energy metabolism, and inflammation. Bile salt-based therapies directly targeting FXR and TGR5 signaling have been evaluated for their therapeutic potential in CMD. More recently, therapeutics targeting bile salt transporters thereby modulating bile salt localization, dynamics, and signaling, have been developed and evaluated in CMD. Here, we discuss the current knowledge on the contribution of bile salt signaling in the pathogenesis of CMD and the potential of bile salt-based therapies for the treatment of CMD.

Targeting Farnesoid X Receptor in Tumor and the Tumor Microenvironment: Implication for Therapy.

The farnesoid-X receptor (FXR), a member of the nuclear hormone receptor superfamily, can be activated by bile acids (BAs). BAs binding to FXR activates BA signaling which is important for maintaining BA homeostasis. FXR is differentially expressed in human organs and exists in immune cells. The dysregulation of FXR is associated with a wide range of diseases including metabolic disorders, inflammatory diseases, immune disorders, and malignant neoplasm. Recent studies have demonstrated that FXR influences tumor cell progression and development through regulating oncogenic and tumor-suppressive pathways, and, moreover, it affects the tumor microenvironment (TME) by modulating TME components. These characteristics provide a new perspective on the FXR-targeted therapeutic strategy in cancer. In this review, we have summarized the recent research data on the functions of FXR in solid tumors and its influence on the TME, and discussed the mechanisms underlying the distinct function of FXR in various types of tumors. Additionally, the impacts on the TME by other BA receptors such as takeda G protein-coupled receptor 5 (TGR5), sphingosine-1-phosphate receptor 2 (S1PR2), and muscarinic receptors (CHRM2 and CHRM3), have been depicted. Finally, the effects of FXR agonists/antagonists in a combination therapy with PD1/PD-L1 immune checkpoint inhibitors and other anti-cancer drugs have been addressed.

Gut microbiota regulates postprandial GLP-1 response via ileal bile acid-TGR5 signaling

ABSTRACT The gut microbiota interacts with intestinal epithelial cells through microbial metabolites to regulate the release of gut hormones. We investigated whether the gut microbiota affects the postprandial glucagon-like peptide-1 (GLP-1) response using antibiotic-treated mice and germ-free mice. Gut microbiome depletion completely abolished postprandial GLP-1 response in the circulation and ileum in a lipid tolerance test. Microbiome depletion did not influence the GLP-1 secretory function of primary ileal cells in response to stimulators in vitro, but dramatically changed the postprandial dynamics of endogenous bile acids, particularly ω-muricholic acid (ωMCA) and hyocholic acid (HCA). The bile acid receptor Takeda G protein-coupled receptor 5 (TGR5) but not farnesoid X receptor (FXR), participated in the regulation of postprandial GLP-1 response in the circulation and ileum, and ωMCA or HCA stimulated GLP-1 secretion via TGR5. Finally, fecal microbiota transplantation or ωMCA and HCA supplementation restored postprandial GLP-1 response. In conclusion, gut microbiota is indispensable for maintaining the postprandial GLP-1 response specifically in the ileum, and bile acid (ωMCA and HCA)-TGR5 signaling is involved in this process. This study helps to understand the essential interplay between the gut microbiota and host in regulating postprandial GLP-1 response and opens the foundation for new therapeutic targets.

Blockade of CCR5 suppresses paclitaxel-induced peripheral neuropathic pain caused by increased deoxycholic acid

Paclitaxel leads to peripheral neuropathy (paclitaxel-induced peripheral neuropathy [PIPN]) in approximately 50% of cancer patients. At present, there are no effective treatment strategies for PIPN, the mechanisms of which also remain unclear. In this study, we performed microbiomeandmetabolome analysis of feces and serum from breast cancer patients with different PIPN grades due to paclitaxel treatment. Our analysis reveals that levels of deoxycholic acid (DCA) are highly increased because of ingrowth of Clostridium species, which is associated with severe neuropathy. DCA, in turn, elevates serum level of C-C motif ligand 5 (CCL5) and induces CCL5 receptor 5 (CCR5) overexpression in dorsal root ganglion (DRG) through the bile acid receptor Takeda G-protein-coupled receptor 5 (TGR5), contributing to neuronal hyperexcitability. Consistent with this, administration of CCR5 antagonist maraviroc suppresses the development of neuropathic nociception. These results implicate gut microbiota/bile acids/CCR5 signaling in the induction of PIPN, thus suggesting a target for PIPN treatment.

TGR5 deficiency-induced anxiety and depression-like behaviors: The role of gut microbiota dysbiosis

Background and purposeAnxiety and depression have been associated with imbalances in the gut microbiota and bile acid metabolism. Takeda G protein-coupled receptor 5 (TGR5), a bile acid receptor involved in metabolism, is influenced by the gut microbiota. This study aimed to investigate the relationship between anxiety, depression, and microbiota using TGR5 knockout mice. MethodsWe employed the following methods: (1) Assessment of behavioral changes, (2) Measurement of 5-HT levels and protein expression, (3) Analysis of stool samples, (4) Utilization of gene sequencing and statistical analysis to identify microbial signatures, (5) Examination of correlations between microbial signatures and 5-HT levels, and (6) Fecal microbiota transplantation experiments of TGR5−/− mice. ResultsThe deletion of TGR5 was found to result in increased anxiety- and depression-like behaviors in mice. TGR5 knockout mice exhibited significant reductions in 5-hydroxytryptamine (5-HT) levels in both serum and hippocampus, accompanied by a decrease in the expression of 5-HT1A receptor in the hippocampus. Moreover, TGR5 deficiency was associated with a decrease in the species richness of the gut microbiota. Specifically, the gut microbiota compositions of TGR5 knockout mice displayed distinct differences compared to their littermates, characterized by higher abundances of Anaeroplasma, Prevotella, Staphylococcus, Jeotgalicoccus, and Helicobacter, and a lower abundance of Bifidobacterium. Notably, a strong association between Jeotgalicoccus as well as Staphylococcus and serum 5-HT levels was observed in co-occurrence network. Furthermore, mice that received fecal microbiota transplants from TGR5−/− mice displayed anxiety and depression -like behaviors, accompanied by alterations in 5-HT levels in the hippocampus and serum. LimitationsStudy limitations for gut bacteria were analyzed at the genus level only. ConclusionTGR5 deletion in mice induces anxiety and depression-like behaviors, linked to reduced 5-HT levels in serum and the hippocampus. Gut microbiota changes play a direct role in these behaviors and serotonin alterations. This implicates TGR5 and gut bacteria in mood regulation, with potential therapeutic implications.

Clinical Significance of Sphingosine 1-phosphate Receptor 2 and Takeda G Protein-coupled Receptor 5 in Extrahepatic Cholangiocarcinoma Patients.

In biliary epithelial cells, two bile acid receptors, sphingosine 1-phosphate receptor 2 (S1PR2) and Takeda G protein-coupled receptor 5 (TGR5) have been reported to trigger cell proliferation, as well as neoplastic cell invasiveness. In this study, we aimed to investigate the clinical significance of S1PR2/ TGR5 expression in extrahepatic cholangiocarcinoma (CCA) patients. Patients who underwent surgical resection of extrahepatic CCA at Korea University Guro Hospital between 2002 and 2018 were included. Data on immunohistochemical staining and H-score of S1PR2 and TGR5 were evaluated using digital image analysis. A total of 115 cases of invasive CCA were analyzed. The H-score of S1PR2 showed a decrease in invasive CCA (p=0.052) but that of TGR5 showed a significant increase (p=0.02). Overall survival and disease-free survival were significantly lower in the low S1PR2 expression group (p<0.05) than in the control group; however, TGR5 expression was not significant (p=0.096). In multivariate analysis, low S1PR2 was only significant for poor prognosis. Low S1PR2 level was the only independent poor prognostic factor in patients with resected extrahepatic CCA.

The molecular effects of Asperuloside against thermogenesis and anti-inflammatory process through multiple recent obesity pathways: An anti-obesity drug discovery by in-silico analysis

ObjectivesAdenosine receptor signaling and suppressing potential pathways such as the aryl hydrocarbon receptor (AHR) and takeda G-protein-coupled receptor-5(TGR5) have been identified as potential targets for enhancing metabolic health. Certain adenosine receptor (AR) ligands have been suggested to reduce inflammation and improve thermogenesis in adipose tissue. MethodsThis study employed in-silico biomolecular fractions of adenosine receptors and other potential targets to understand the mechanism of action of Asperuloside. Additionally, the anti-obesity potential of Asperuloside, a dual-acting ligand with A2A adenosine receptor (A2AAR) agonist and A3 adenosine receptor (A3AR) agonist activities, were examined using computational analysis in the obesity model. The impact of Asperuloside on inflammation and thermogenesis was studied through diverse protein structures such as the A2AAR complex with agonist/A2AAR complex with antagonist, the rhodopsin mutant with bound galphact peptide (as A3 adenosine receptor), The Human TGR5 complex with synthetic agonist 23H, and AHR receptors antagonism. ResultsThe study found that Asperuloside has therapeutic affinity for the binding site of adenosine receptors and revealed a novel binding interaction that helps reduce inflammation and improve thermogenesis-mediated obesity. ConclusionAsperuloside may have anti-obesity effects through its dual-acting ligand with A2AAR and A3AR agonist activities. This study provides a major step towards understanding the mechanism of action of Asperuloside and its potential use as an anti-obesity drug. In vivo tests will help ascertain its pharmacokinetic characteristics, metabolite production in animals, and the effects of chronic daily absorption.

Bear bile powder alleviates Parkinson's disease-like behavior in mice by inhibiting astrocyte-mediated neuroinflammation.

Parkinson's disease (PD) is a common neurodegenerative disease in middle-aged and elderly people. In particular, increasing evidence has showed that astrocyte-mediated neuroinflammation is involved in the pathogenesis of PD. As a precious traditional Chinese medicine, bear bile powder (BBP) has a long history of use in clinical practice. It has numerous activities, such as clearing heat, calming the liver wind and anti-inflammation, and also exhibits good therapeutic effect on convulsive epilepsy. However, whether BBP can prevent the development of PD has not been elucidated. Hence, this study was designed to explore the effect and mechanism of BBP on suppressing astrocyte-mediated neuroinflammation in a mouse model of PD. PD-like behavior was induced in the mice by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (30 mg·kg-1) for five days, followed by BBP (50, 100, and 200 mg·kg-1) treatment daily for ten days. LPS stimulated rat C6 astrocytic cells were used as a cell model of neuroinflammation. THe results indicated that BBP treatment significantly ameliorated dyskinesia, increased the levels of tyrosine hydroxylase (TH) and inhibited astrocyte hyperactivation in the substantia nigra (SN) of PD mice. Furthermore, BBP decreased the protein levels of glial fibrillary acidic protein (GFAP), cyclooxygenase 2 (COX2) and inducible nitric oxide synthase (iNOS), and up-regulated the protein levels of takeda G protein-coupled receptor 5 (TGR5) in the SN. Moreover, BBP significantly activated TGR5 in a dose-dependent manner, and decreased the protein levels of GFAP, iNOS and COX2, as well as the mRNA levels of GFAP, iNOS, COX2, interleukin (IL) -1β, IL-6 and tumor necrosis factor-α (TNF-α) in LPS-stimulated C6 cells. Notably, BBP suppressed the phosphorylation of protein kinase B (AKT), inhibitor of NF-κB (IκBα) and nuclear factor-κB (NF-κB) proteins in vivo and in vitro. We also observed that TGR5 inhibitor triamterene attenuated the anti-neuroinflammatory effect of BBP on LPS-stimulated C6 cells. Taken together, BBP alleviates the progression of PD mice by suppressing astrocyte-mediated inflammation via TGR5.

Effect and mechanism of Puerariae Lobatae Radix in alleviating insulin resistance in T2DM db/db mice based on intestinal flora

This study aimed to examine the effect and underlying mechanism of Puerariae Lobatae Radix on insulin resistance in db/db mice with type 2 diabetes mellitus(T2DM) based on the analysis of intestinal flora. Fifty db/db mice were randomly divided into a model group(M group), a metformin group(YX group), a high-dose Puerariae Lobatae Radix group(YGG group), a medium-dose Puerariae Lobatae Radix group(YGZ group), and a low-dose Puerariae Lobatae Radix group(YGD group). Another 10 db/m mice were assigned to the normal group(K group). After continuous administration for eight weeks, body weight and blood sugar of mice were measured. Enzyme linked immunosorbent assay(ELISA) was used to detect glycosylated serum protein(GSP) and fasting serum insulin(FINS), and insulin resistance index(HOMA-IR) was calculated. The histopathological changes in the pancreas were observed by HE staining. Tumor necrosis factor(TNF)-α expression in the pancreas was detected using immunohistochemistry. The structural changes in fecal intestinal flora in the K, M, and YGZ groups were detected by 16S rRNA. Western blot was used to detect the expression of farnesoid X receptor(FXR) and takeda G protein-coupled receptor 5(TGR5) in the ileum, cholesterol 7α-hydroxylase(CYP7A1) and sterol 27α-hydroxylase(CYP27A1) in the liver, and G protein-coupled receptors 41(GPR41) and 43(GPR43) in the colon. Compared with the K group, the M group showed increased body weight, blood sugar, serum GSP, fasting blood glucose(FBG), and FINS, increased HOMA-IR, inflammatory infiltration of islet cells, necrosis and degeneration of massive acinar cells, unclear boundary between islet cells and acinar cells, disturbed intestinal flora, and down-regulated FXR, TGR5, CYP7A1, CYP27A1, GPR41, and GPR43. Compared with the M group, the YX, YGG, YGZ, and YGD groups showed decreased body weight, blood sugar, serum GSP, FBG, and FINS, islet cells with intact and clumpy morphology and clear boundary, necrosis of a few acinar cells, and more visible islet cells. The intestinal flora in the YGZ group changed from phylum to genus levels, and the relative abundance of intestinal flora affecting the metabolites of intestinal flora increased. The protein expression of FXR, TGR5, CYP7A1, CYP27A1, GPR41, and GPR43 increased. The results show that Puerariae Lobatae Radix can improve the inflammatory damage of pancreatic islet cells and reduce insulin resistance in db/db mice with T2DM. The mechanism of action may be related to the increase in the abundance of Actinobacteria, Bifidobacterium, and Bacteroides in the intestinal tract and the protein expression related to metabolites of intestinal flora.

Research Progress of Takeda G Protein-Coupled Receptor 5 in Metabolic Syndrome.

Bile acids are acknowledged as signaling molecules involved in metabolic syndrome. The Takeda G protein-coupled receptor 5 (TGR5) functions as a significant bile acid receptor. The accumulated evidence suggests that TGR5 involves lipid homeostasis, glucose metabolism, and inflammation regulation. In line with this, recent preclinical studies also demonstrate that TGR5 plays a significant role in the generation and progression of metabolic syndrome, encompassing type 2 diabetes mellitus, obesity, atherosclerosis, and non-alcoholic fatty liver disease (NAFLD). In this review, we discuss the role of TGR5 in metabolic syndrome, illustrating the underlying mechanisms and therapeutic targets.

Discovery and biological evaluation of cholic acid derivatives as potent TGR5 positive allosteric modulators

In this study, twenty-two novel cholic acid (CA) derivatives were designed and synthesized as potential Takeda G protein-coupled receptor 5 (TGR5) positive allosteric modulators (PAMs) using structure-based drug design (SBDD). GloSensor cAMP accumulation assay was employed to assess the functional activity and allosteric mechanism of final compounds. Biological results showed that all target compounds were able to activate the TGR5 in the cAMP formation assay. Remarkably, compound B1, selective methylation of 7-OH in CA, exhibited 5-fold higher activity for TGR5 compared to that of CA. Moreover, B1 positively modulate the functional activity of chenodeoxycholic acid (CDCA) in TGR5, indicating that B1 is a TGR5 PAM. On the other hand, 12-carbonyl derivative A1 displayed 7-fold higher potency for TGR5 relative to CA. Unexpectedly, compound A1 exhibited the same positive allosteric effect as B1, suggesting that A1 is a TGR5 PAM as well. Molecular modeling study revealed that 12-carbonyl in A1 and 12-OH in B1 formed H-bolds with the key amino acid Thr131, which are significant for TGR5 allosteric property. Taken together, we found two potent TGR5 PAMs A1 and B1 through SBDD, which could be used as lead compounds to further study TGR5 allosteric functionality.

Design, Synthesis, Computational and Biological Evaluation of Novel Structure Fragments Based on Lithocholic Acid (LCA).

The regulation of bile acid pathways has become a particularly promising therapeutic strategy for a variety of metabolic disorders, cancers, and diseases. However, the hydrophobicity of bile acids has been an obstacle to clinical efficacy due to off-target effects from rapid drug absorption. In this report, we explored a novel strategy to design new structure fragments based on lithocholic acid (LCA) with improved hydrophilicity by introducing a polar "oxygen atom" into the side chain of LCA, then (i) either retaining the carboxylic acid group or replacing the carboxylic acid group with (ii) a diol group or (iii) a vinyl group. These novel fragments were evaluated using luciferase-based reporter assays and the MTS assay. Compared to LCA, the result revealed that the two lead compounds 1a-1b were well tolerated in vitro, maintaining similar potency and efficacy to LCA. The MTS assay results indicated that cell viability was not affected by dose dependence (under 25 µM). Additionally, computational model analysis demonstrated that compounds 1a-1b formed more extensive hydrogen bond networks with Takeda G protein-coupled receptor 5 (TGR5) than LCA. This strategy displayed a potential approach to explore the development of novel endogenous bile acids fragments. Further evaluation on the biological activities of the two lead compounds is ongoing.

High body temperature increases gut microbiota-dependent host resistance to influenza A virus and SARS-CoV-2 infection

Fever is a common symptom of influenza and coronavirus disease 2019 (COVID-19), yet its physiological role in host resistance to viral infection remains less clear. Here, we demonstrate that exposure of mice to the high ambient temperature of 36 °C increases host resistance to viral pathogens including influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). High heat-exposed mice increase basal body temperature over 38 °C to enable more bile acids production in a gut microbiota-dependent manner. The gut microbiota-derived deoxycholic acid (DCA) and its plasma membrane-bound receptor Takeda G-protein-coupled receptor 5 (TGR5) signaling increase host resistance to influenza virus infection by suppressing virus replication and neutrophil-dependent tissue damage. Furthermore, the DCA and its nuclear farnesoid X receptor (FXR) agonist protect Syrian hamsters from lethal SARS-CoV-2 infection. Moreover, we demonstrate that certain bile acids are reduced in the plasma of COVID-19 patients who develop moderate I/II disease compared with the minor severity of illness group. These findings implicate a mechanism by which virus-induced high fever increases host resistance to influenza virus and SARS-CoV-2 in a gut microbiota-dependent manner.

Protective effects of dioscin against Parkinson's disease via regulating bile acid metabolism through remodeling gut microbiome/GLP-1 signaling

It is necessary to explore potent therapeutic agents via regulating gut microbiota and metabolism to combat Parkinson's disease (PD). Dioscin, a bioactive steroidal saponin, shows various activities. However, its effects and mechanisms against PD are limited. In this study, dioscin dramatically alleviated neuroinflammation and oxidative stress, and restored the disorders of mice induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). 16 S rDNA sequencing assay demonstrated that dioscin reversed MPTP-induced gut dysbiosis to decrease Firmicutes-to-Bacteroidetes ratio and the abundances of Enterococcus, Streptococcus, Bacteroides and Lactobacillus genera, which further inhibited bile salt hydrolase (BSH) activity and blocked bile acid (BA) deconjugation. Fecal microbiome transplantation test showed that the anti-PD effect of dioscin was gut microbiota-dependent. In addition, non-targeted fecal metabolomics assays revealed many differential metabolites in adjusting steroid biosynthesis and primary bile acid biosynthesis. Moreover, targeted bile acid metabolomics assay indicated that dioscin increased the levels of ursodeoxycholic acid, tauroursodeoxycholic acid, taurodeoxycholic acid and β-muricholic acid in feces and serum. In addition, ursodeoxycholic acid administration markedly improved the protective effects of dioscin against PD in mice. Mechanistic test indicated that dioscin significantly up-regulated the levels of takeda G protein-coupled receptor 5 (TGR5), glucagon-like peptide-1 receptor (GLP-1R), GLP-1, superoxide dismutase (SOD), and down-regulated NADPH oxidases 2 (NOX2) and nuclear factor-kappaB (NF-κB) levels. Our data indicated that dioscin ameliorated PD phenotype by restoring gut dysbiosis and regulating bile acid-mediated oxidative stress and neuroinflammation via targeting GLP-1 signal in MPTP-induced PD mice, suggesting that the compound should be considered as a prebiotic agent to treat PD in the future.