OBJECTIVE Takeda G protein-coupled receptor 5(TGR5)is recognized as a promising target for type 2 diabetes and metabolic syndrome;its expression has been demonstrat⁃ed in the brain and is thought to be neuroprotec⁃tiv...OBJECTIVE Takeda G protein-coupled receptor 5(TGR5)is recognized as a promising target for type 2 diabetes and metabolic syndrome;its expression has been demonstrat⁃ed in the brain and is thought to be neuroprotec⁃tive.Here,we hypothesize that dysfunction of central TGR5 may contribute to the pathogene⁃sis of depression.METHODS In well-established chronic social defeat stress(CSDS)and chronic restraint stress(CRS)models of depression,we investigated the functional roles of TGR5 in CA3 pyramidal neurons(PyNs)and underlying mech⁃anisms of the neuronal circuit in depression(for in vivo studies,n=10;for in vitro studies,n=5-10)using fiber photometry;optogenetic,chemoge⁃netic,pharmacological,and molecular profiling techniques;and behavioral tests.RESULTS Both CSDS and CRS most significantly reduced TGR5 expression of hippocampal CA3 PyNs.Genetic overexpression of TGR5 in CA3 PyNs or intra-CA3 infusion of INT-777,a specific agonist,protected against CSDS and CRS,exerting sig⁃nificant antidepressant-like effects that were mediated via CA3 PyN activation.Conversely,genetic knockout or TGR5 knockdown in CA3 facilitated stress-induced depression-like behav⁃iors.Re-expression of TGR5 in CA3 PyNs rather than infusion of INT-777 significantly improved depression-like behaviors in Tgr5 knockout mice exposed to CSDS or CRS.Silencing and stimula⁃tion of CA3 PyNs→somatostatin-GABAergic(gamma-aminobutyric acidergic)neurons of the dorsolateral septum circuit bidirectionally regulat⁃ed depression-like behaviors,and blockade of this circuit abrogated the antidepressant-like effects from TGR5 activation of CA3 PyNs.CON⁃CLUSION TGR5 can regulate depression via CA3 PyNs→somatostatin-GABAergic neurons of dorsolateral septum transmission,suggesting that TGR5 could be a novel target for developing antidepressants.展开更多
BACKGROUND Colon cancer cell lines are widely used for research and for the screening of drugs that specifically target the stem cell compartment of colon cancers.It was reported that colon cancer carcinoma specimens ...BACKGROUND Colon cancer cell lines are widely used for research and for the screening of drugs that specifically target the stem cell compartment of colon cancers.It was reported that colon cancer carcinoma specimens contain a subset of leucine-rich repeatcontaining G protein-coupled receptor 5(LGR5)-expressing stem cells,these socalled“tumour-initiating”cells,reminiscent in their properties of the normal intestinal stem cells(ISCs),may explain the apparent heterogeneity of colon cancer cell lines.Also,colon cancer is initiated by aberrant Wnt signaling in ISCs known to express high levels of LGR5.Furthermore,in vivo reports demonstrate the clonal expansion of intestinal adenomas from a single LGR5-expressing cell.AIM To investigate whether colon cancer cell lines contain cancer stem cells and to characterize these putative cancer stem cells.METHODS A portable fluorescent reporter construct based on a conserved fragment of the LGR5 promoter was used to isolate the cell compartments expressing different levels of LGR5 in two widely used colon cancer cell lines(Caco-2 and LoVo).These cells were then characterized according to their proliferation capacity,gene expression signatures of ISC markers,and their tumorigenic properties in vivo and in vitro.RESULTS The data revealed that the LGR5 reporter can be used to identify and isolate a classical intestinal crypt stem cell-like population from the Caco-2,but not from the LoVo,cell lines,in which the cancer stem cell population is more akin to B lymphoma Moloney murine leukemia virus insertion region 1 homolog(+4 crypt)stem cells.This sub-population within Caco-2 cells exhibits an intestinal cancer stem cell gene expression signature and can both self-renew and generate differentiated LGR5 negative progeny.Our data also show that cells expressing high levels of LGR5/enhanced yellow fluorescent protein(EYFP)from this cell line exhibit tumorigenic-like properties in vivo and in vitro.In contrast,cell compartments of LoVo that are expressing high levels of LGR5/EYFP did not show these stem cell-like properties.Thus,cells that exhibit high levels of LGR5/EYFP expression represent the cancer stem cell compartment of Caco-2 colon cancer cells,but not LoVo cells.CONCLUSION Our findings highlight the presence of a spectrum of different ISC-like compartments in different colon cancer cell lines.Their existence is an important consideration for their screening applications and should be taken into account when interpreting drug screening data.We have generated a portable LGR5-reporter that serves as a valuable tool for the identification and isolation of different colon cancer stem cell populations in colon cancer lines.展开更多
Milk fat globule membrane(MFGM),which contains abundant glycoproteins and phospholipids,exerts beneficial effects on intestinal health and immunomodulation.The aim of this study was to evaluate the protective effects ...Milk fat globule membrane(MFGM),which contains abundant glycoproteins and phospholipids,exerts beneficial effects on intestinal health and immunomodulation.The aim of this study was to evaluate the protective effects and possible underlying mechanisms of MFGM on cow’s milk allergy(CMA)in aβ-lactoglobulin(BLG)-induced allergic mice model.MFGM was supplemented to allergic mice induced by BLG at a dose of 400 mg/kg body weight.Results demonstrated that MFGM alleviated food allergy symptoms,decreased serum levels of lipopolysaccharide,pro-inflammatory cytokines,immunoglobulin(Ig)E,Ig G1,and Th2 cytokines including interleukin(IL)-4,while increased serum levels of Th1 cytokines including interferon-γand regulatory T cells(Tregs)cytokines including IL-10 and transforming growth factor-β.MFGM modulated gut microbiota and enhanced intestinal barrier of BLG-allergic mice,as evidenced by decreased relative abundance of Desulfobacterota,Rikenellaceae,Lachnospiraceae,and Desulfovibrionaceae,while increased relative abundance of Bacteroidetes,Lactobacillaceae and Muribaculaceae,and enhanced expressions of tight junction proteins including Occludin,Claudin-1 and zonula occludens-1.Furthermore,MFGM increased fecal short-chain fatty acids(SCFAs)levels,which elevated G protein-coupled receptor(GPR)43 and GPR109A expressions.The increased expressions of GPR43 and GPR109A induced CD103+dendritic cells accumulation and promoted Tregs differentiation in mesenteric lymph node to a certain extent.In summary,MFGM alleviated CMA in a BLG-induced allergic mice model through enhancing intestinal barrier and promoting Tregs differentiation,which may be correlated with SCFAs-mediated activation of GPRs.These findings suggest that MFGM may be useful as a promising functional ingredient against CMA.展开更多
Nonalcoholic fatty liver disease(NAFLD)is a broad-spectrum disease,ranging from simple hepatic steatosis to nonalcoholic steatohepatitis,which can progress to cirrhosis and liver cancer.Abnormal hepatic lipid accumula...Nonalcoholic fatty liver disease(NAFLD)is a broad-spectrum disease,ranging from simple hepatic steatosis to nonalcoholic steatohepatitis,which can progress to cirrhosis and liver cancer.Abnormal hepatic lipid accumulation is the major manifestation of this disease,and lipotoxicity promotes NAFLD progression.In addition,intermediate metabolites such as succinate can stimulate the activation of hepatic stellate cells to produce extracellular matrix proteins,resulting in progression of NAFLD to fibrosis and even cirrhosis.G protein-coupled receptors(GPCRs)have been shown to play essential roles in metabolic disorders,such as NAFLD and obesity,through their function as receptors for bile acids and free fatty acids.In addition,GPCRs link gut microbiota-mediated connections in a variety of diseases,such as intestinal diseases,hepatic steatosis,diabetes,and cardiovascular diseases.The latest findings show that gut microbiota-derived acetate contributes to liver lipogenesis by converting dietary fructose into hepatic acetyl-CoA and fatty acids.GPCR agonists,including peptides and natural products like docosahexaenoic acid,have been applied to investigate their role in liver diseases.Therapies such as probiotics and GPCR agonists may be applied to modulate GPCR function to ameliorate liver metabolism syndrome.This review summarizes the current findings regarding the role of GPCRs in the development and progression of NAFLD and describes some preclinical and clinical studies of GPCR-mediated treatment.Overall,understanding GPCR-mediated signaling in liver disease may provide new therapeutic options for NAFLD.展开更多
With the high prevalence of obesity, diabetes, and otherfeatures of the metabolic syndrome in United States, nonalcoholic fatty liver disease(NAFLD) has inevitably become a very prevalent chronic liver disease and is ...With the high prevalence of obesity, diabetes, and otherfeatures of the metabolic syndrome in United States, nonalcoholic fatty liver disease(NAFLD) has inevitably become a very prevalent chronic liver disease and is now emerging as one of the leading indications for liver transplantation. Insulin resistance and derangement of lipid metabolism, accompanied by activation of the pro-inflammatory response and fibrogenesis, are essential pathways in the development of the more clinically significant form of NAFLD, known as nonalcoholic steatohepatitis(NASH). Recent advances in the functional characterization of bile acid receptors, such as farnesoid X receptor(FXR) and transmembrane G protein-coupled receptor(TGR) 5, have provided further insight in the pathophysiology of NASH and have led to the development of potential therapeutic targets for NAFLD and NASH. Beyond maintaining bile acid metabolism, FXR and TGR5 also regulate lipid metabolism, maintain glucose homeostasis, increase energy expenditure, and ameliorate hepatic inflammation. These intriguing features have been exploited to develop bile acid analogues to target pathways in NAFLD and NASH pathogenesis. This review provides a brief overview of the pathogenesis of NAFLD and NASH, and then delves into the biological functions of bile acid receptors, particularly with respect to NASH pathogenesis, with a description of the associated experimental data, and, finally, we discuss the prospects of bile acid analogues in the treatment of NAFLD and NASH.展开更多
The intensive crosstalk between the liver and the intestine performs many essential functions.This crosstalk is important for natural immune surveillance,adaptive immune response regulation and nutrient metabolism and...The intensive crosstalk between the liver and the intestine performs many essential functions.This crosstalk is important for natural immune surveillance,adaptive immune response regulation and nutrient metabolism and elimination of toxic bacterial metabolites.The interaction between the gut microbiome and bile acids is bidirectional.The gut microbiome regulates the synthesis of bile acids and their biological signaling activity and circulation via enzymes.Similarly,bile acids also shape the composition of the gut microbiome by modulating the host’s natural antibacterial defense and the intestinal immune system.The interaction between bile acids and the gut microbiome has been implicated in the pathophysiology of many intestinal and extra intestinal diseases,especially liver diseases.As essential mediators of the gut-liver crosstalk,bile acids regulate specific host metabolic pathways and modulate the inflammatory responses through farnesoid X-activated receptor and G protein-coupled bile acid receptor 1.Several clinical trials have demonstrated the signaling effects of bile acids in the context of liver diseases.We hypothesize the existence of a gut microbiome-bile acids-liver triangle and explore the potential therapeutic strategies for liver diseases targeting the triangle.展开更多
Recent studies have revealed that bile acids(BAs)are not only facilitators of dietary lipid absorption but also important signaling molecules exerting multiple physiological functions.Some major signaling pathways inv...Recent studies have revealed that bile acids(BAs)are not only facilitators of dietary lipid absorption but also important signaling molecules exerting multiple physiological functions.Some major signaling pathways involving the nuclear BAs receptor farnesoid X receptor and the G protein-coupled BAs receptor TGR5/M-BAR have been identified to be the targets of BAs.BAs regulate their own homeostasis via signaling pathways.BAs also affect diverse metabolic pathways including glucose metabolism,lipid metabolism and energy expenditure.This paper suggests the mechanism of controlling metabolism via BA signaling and demonstrates that BA signaling is an attractive therapeutic target of the metabolic syndrome.展开更多
BACKGROUND Gut microbiota and its metabolites may be involved in the pathogenesis of inflammatory bowel disease.Several clinical studies have recently shown that patients with ulcerative colitis(UC)have altered profil...BACKGROUND Gut microbiota and its metabolites may be involved in the pathogenesis of inflammatory bowel disease.Several clinical studies have recently shown that patients with ulcerative colitis(UC)have altered profiles of fecal bile acids(BAs).It was observed that BA receptors Takeda G-protein-coupled receptor 5(TGR5)and vitamin D receptor(VDR)participate in intestinal inflammatory responses by regulating NF-ĸB signaling.We hypothesized that altered profiles of fecal BAs might be correlated with gut microbiota and inflammatory responses in patients with UC.AIM To investigate the changes in fecal BAs and analyze the relationship of BAs with gut microbiota and inflammation in patients with UC.METHODS The present study used 16S rDNA sequencing technology to detect the differences in the intestinal flora between UC patients and healthy controls(HCs).Fecal BAs were measured by targeted metabolomics approaches.Mucosal TGR5 and VDR expression was analyzed using immunohistochemistry,and serum inflammatory cytokine levels were detected by ELISA.RESULTS Thirty-two UC patients and twenty-three HCs were enrolled in this study.It was found that the diversity of gut microbiota in UC patients was reduced compared with that in HCs.Firmicutes,Clostridium IV,Butyricicoccus,Clostridium XlVa,Faecalibacterium,and Roseburia were significantly decreased in patients with UC(P=3.75E-05,P=8.28E-07,P=0.0002,P=0.003,P=0.0003,and P=0.0004,respectively).Proteobacteria,Escherichia,Enterococcus,Klebsiella,and Streptococcus were significantly enriched in the UC group(P=2.99E-09,P=3.63E-05,P=8.59E-05,P=0.003,and P=0.016,respectively).The concentrations of fecal secondary BAs,such as lithocholic acid,deoxycholic acid,glycodeoxycholic acid,glycolithocholic acid,and taurolithocholate,in UC patients were significantly lower than those in HCs(P=8.1E-08,P=1.2E-07,P=3.5E-04,P=1.9E-03,and P=1.8E-02,respectively)and were positively correlated with Butyricicoccus,Roseburia,Clostridium IV,Faecalibacterium,and Clostridium XlVb(P<0.01).The concentrations of primary BAs,such as taurocholic acid,cholic acid,taurochenodeoxycholate,and glycochenodeoxycholate,in UC patients were significantly higher than those in HCs(P=5.3E-03,P=4E-02,P=0.042,and P=0.045,respectively)and were positively related to Enterococcus,Klebsiella,Streptococcus,Lactobacillus,and pro-inflammatory cytokines(P<0.01).The expression of TGR5 was significantly elevated in UC patients(0.019±0.013 vs 0.006±0.003,P=0.0003).VDR expression in colonic mucosal specimens was significantly decreased in UC patients(0.011±0.007 vs 0.016±0.004,P=0.033).CONCLUSION Fecal BA profiles are closely related to the gut microbiota and serum inflammatory cytokines.Dysregulation of the gut microbiota and altered constitution of fecal BAs may participate in regulating inflammatory responses via the BA receptors TGR5 and VDR.展开更多
BACKGROUND In the heart,aldosterone(Aldo)binds the mineralocorticoid receptor(MR)to exert damaging,adverse remodeling-promoting effects.We recently showed that G protein-coupled receptor-kinase(GRK)-5 blocks the cardi...BACKGROUND In the heart,aldosterone(Aldo)binds the mineralocorticoid receptor(MR)to exert damaging,adverse remodeling-promoting effects.We recently showed that G protein-coupled receptor-kinase(GRK)-5 blocks the cardiac MR by directly phosphorylating it,thereby repressing its transcriptional activity.MR antagonist(MRA)drugs block the cardiac MR reducing morbidity and mortality of advanced human heart failure.Non-steroidal MRAs,such as finerenone,may provide better cardio-protection against Aldo than classic,steroidal MRAs,like spironolactone and eplerenone.AIM To investigate potential differences between finerenone and eplerenone at engaging GRK5-dependent cardiac MR phosphorylation and subsequent blockade.METHODS We used H9c2 cardiomyocytes,which endogenously express the MR and GRK5.RESULTS GRK5 phosphorylates the MR in H9c2 cardiomyocytes in response to finerenone but not to eplerenone.Unlike eplerenone,finerenone alone potently and efficiently suppresses cardiac MR transcriptional activity,thus displaying inverse agonism.GRK5 is necessary for finerenone’s inverse agonism,since GRK5 genetic deletion renders finerenone incapable of blocking cardiac MR transcriptional activity.Eplerenone alone does not fully suppress cardiac MR basal activity regardless of GRK5 expression levels.Finally,GRK5 is necessary for the antiapoptotic,anti-oxidative,and anti-fibrotic effects of both finerenone and eplerenone against Aldo,as well as for the higher efficacy and potency of finerenone at blocking Aldo-induced apoptosis,oxidative stress,and fibrosis.CONCLUSION Finerenone,but not eplerenone,induces GRK5-dependent cardiac MR inhibition,which underlies,at least in part,its higher potency and efficacy,compared to eplerenone,as an MRA in the heart.GRK5 acts as a co-repressor of the cardiac MR and is essential for efficient MR antagonism in the myocardium.展开更多
Nonalcoholic fatty liver disease(NAFLD)is the most common chronic liver disease worldwide.Fat accumulation“sensitizes”the liver to insult and leads to nonalcoholic steatohepatitis(NASH).G protein-coupled receptor 35...Nonalcoholic fatty liver disease(NAFLD)is the most common chronic liver disease worldwide.Fat accumulation“sensitizes”the liver to insult and leads to nonalcoholic steatohepatitis(NASH).G protein-coupled receptor 35(GPR35)is involved in metabolic stresses,but its role in NAFLD is unknown.We report that hepatocyte GPR35 mitigates NASH by regulating hepatic cholesterol homeostasis.Specifically,we found that GPR35 overexpression in hepatocytes protected against high-fat/cholesterol/fructose(HFCF)diet-induced steatohepatitis,whereas loss of GPR35 had the opposite effect.Administration of the GPR35 agonist kynurenic acid(Kyna)suppressed HFCF diet-induced steatohepatitis in mice.Kyna/GPR35 induced expression of StAR-related lipid transfer protein 4(STARD4)through the ERK1/2 signaling pathway,ultimately resulting in hepatic cholesterol esterification and bile acid synthesis(BAS).The overexpression of STARD4 increased the expression of the BAS rate-limiting enzymes cytochrome P450 family 7 subfamily A member 1(CYP7A1)and CYP8B1,promoting the conversion of cholesterol to bile acid.The protective effect induced by GPR35 overexpression in hepatocytes disappeared in hepatocyte STARD4-knockdown mice.STARD4 overexpression in hepatocytes reversed the aggravation of HFCF diet-induced steatohepatitis caused by the loss of GPR35 expression in hepatocytes in mice.Our findings indicate that the GPR35–STARD4 axis is a promising therapeutic target for NAFLD.展开更多
Maintaining bile acid homeostasis is essential for metabolic health.Bile acid homeostasis encompasses a complex interplay between biosynthesis,conjugation,secretion,and reabsorption.Beyond their vital role in digestio...Maintaining bile acid homeostasis is essential for metabolic health.Bile acid homeostasis encompasses a complex interplay between biosynthesis,conjugation,secretion,and reabsorption.Beyond their vital role in digestion and absorption of lipid-soluble nutrients,bile acids are pivotal in systemic metabolic regulation.Recent studies have linked bile acid dysregulation to the pathogenesis of metabolic diseases,including obesity,type 2 diabetes melli-tus(T2DM),and metabolic dysfunction-associated steatotic liver disease(MASLD).Bile acids are essential signaling molecules that regulate many critical biological processes,including lipid metabolism,energy expenditure,insulin sensitivity,and glucose metabolism.Disruption in bile acid homeostasis contributes to metabolic disease via altered bile acid feedback mechanisms,hormonal dysregu-lation,interactions with the gut microbiota,and changes in the expression and function of bile acid transporters and receptors.This review summarized the essential molecular pathways and regulatory mechanisms through which bile acid dysregulation contributes to the pathogenesis and progression of obesity,T2DM,and MASLD.We aim to underscore the significance of bile acids as potential diag-nostic markers and therapeutic agents in the context of metabolic diseases,providing insights into their application in translational medicine.展开更多
Objective： To investigate Leucine-rich repeat-containing G protein-coupled receptor 5 （LGR5） expressions in gastric cancer and to evaluate its clinical significance. Methods： LGR5 expression was assessed by immuno...Objective： To investigate Leucine-rich repeat-containing G protein-coupled receptor 5 （LGR5） expressions in gastric cancer and to evaluate its clinical significance. Methods： LGR5 expression was assessed by immunohistochemistry in 257 gastric cancer patients after surgery. The relationships between LGR5 expression and clinicopathological features and patients prognosis were statistically analyzed. Results： The expression of LGR5 was significantly higher in gastric cancers as a cancer stem cell marker than in adjacent normal tissues （P〈0.001）, and more frequently in patients with intestinal type, well-moderate differentiation and stage I and II （P〈0.05）. Although we found gastric cancer patients with LGR5 positive expression had a poorer prognosis, it didn＇t meet statistical significance （P〉0.05）. LGR5 negative expression was significantly related to the favorable overall survival in stage I and II gastric cancer patients （P〈0.05）. Furthermore, patients with high LGR5 expression tended to be more likely to get progression and have poorer progress-free survival （P〈0.05）. Multivariate Cox regression analysis revealed that LGR5 expression was an independent factor of overall survival for the patients with stage I and II gastric cancer （P〈0.05）. Conclusions： Our results show that LGR5 may play an important role in tumorigenesis and progression and would be a powerful marker to predict the prognosis of patients with stage I and II gastric cancer.展开更多
AIM:To investigate the differential expression of leu-cine-rich repeat-containing G protein-coupled receptor5(LGR5)in gastric cancer tissues and its significance related to tumor growth and spread.METHODS:Formalin-fix...AIM:To investigate the differential expression of leu-cine-rich repeat-containing G protein-coupled receptor5(LGR5)in gastric cancer tissues and its significance related to tumor growth and spread.METHODS:Formalin-fixed biopsy specimens of intestinal metaplasia(n=90),dysplasia(n=53),gastric adenocarcinoma(n=180),metastases in lymph nodes and the liver(n=15),and lesion-adjacent normal gastric mucosa(controls;n=145)were obtained for analysis from the Peking University Cancer Hospital’s Department of Pathology and Gastrointestinal Surgery tissue archives(January 2003 to December 2011).The biopsied patients’demographic and clinicopathologic data were retrieved from the hospital’s medical records database.Each specimen was subjected to histopathological typing to classify the tumor node metastasis(TNM)stage and to immunohistochemistry staining to detect the expression of the cancer stem cell marker LGR5.The intergroup differences in LGR5 expression were assessed by Spearman’s rank correlation analysis,and the relationship between LGR5 expression level and the patients’clinicopathological characteristics was evaluated by theχ2test or Fisher’s exact test.RESULTS:Significantly more gastric cancer tissues showed LGR5+staining than normal control tissues(all P<0.01),with immunoreactivity detected in 72.2%(65/90)and 50.9%(27/53)of intestinal metaplasia and dysplasia specimens,respectively,52.8%(95/180)of gastric adenocarcinoma specimens,and 73.3%%(11/15)of metastasis specimens,but 26.9%(39/145)of lesion-adjacent normal gastric mucosa specimens.Comparison of the intensity of LGR5+staining showed an increasing trend that generally followed increasing dedifferentiation and tumor spread(normal tissue<dysplasia,<gastric adenocarcinoma<metastasis;all P<0.001),with the exception of expression level detected in intestinal metaplasia which was higher than that in normal gastric tissues(P<0.001).Moreover,gastric cancer-associated enhanced expression of LGR5 was found to be signifcantly associated with age,tumor differentiation,Lauren type and TNM stage(Ⅰ+ⅡvsⅢ+Ⅳ)(all P<0.05),but not with sex,tumor site,location,size,histology,lymphovascular invasion,depth of invasion,lymph node metastasis or distant metastasis.Patients with LGR5+gastric cancer specimens and without signs of metastasis from the original biopsy experienced more frequent rates of recurrence or metastasis during follow-up than patients with LGR5-specimens(P<0.05).CONCLUSION:Enhanced LGR5 is related to progressive dedifferentiation and metastasis of gastric cancer,indicating the potential of this receptor as an early diagnostic and prognostic biomarker.展开更多
文摘OBJECTIVE Takeda G protein-coupled receptor 5(TGR5)is recognized as a promising target for type 2 diabetes and metabolic syndrome;its expression has been demonstrat⁃ed in the brain and is thought to be neuroprotec⁃tive.Here,we hypothesize that dysfunction of central TGR5 may contribute to the pathogene⁃sis of depression.METHODS In well-established chronic social defeat stress(CSDS)and chronic restraint stress(CRS)models of depression,we investigated the functional roles of TGR5 in CA3 pyramidal neurons(PyNs)and underlying mech⁃anisms of the neuronal circuit in depression(for in vivo studies,n=10;for in vitro studies,n=5-10)using fiber photometry;optogenetic,chemoge⁃netic,pharmacological,and molecular profiling techniques;and behavioral tests.RESULTS Both CSDS and CRS most significantly reduced TGR5 expression of hippocampal CA3 PyNs.Genetic overexpression of TGR5 in CA3 PyNs or intra-CA3 infusion of INT-777,a specific agonist,protected against CSDS and CRS,exerting sig⁃nificant antidepressant-like effects that were mediated via CA3 PyN activation.Conversely,genetic knockout or TGR5 knockdown in CA3 facilitated stress-induced depression-like behav⁃iors.Re-expression of TGR5 in CA3 PyNs rather than infusion of INT-777 significantly improved depression-like behaviors in Tgr5 knockout mice exposed to CSDS or CRS.Silencing and stimula⁃tion of CA3 PyNs→somatostatin-GABAergic(gamma-aminobutyric acidergic)neurons of the dorsolateral septum circuit bidirectionally regulat⁃ed depression-like behaviors,and blockade of this circuit abrogated the antidepressant-like effects from TGR5 activation of CA3 PyNs.CON⁃CLUSION TGR5 can regulate depression via CA3 PyNs→somatostatin-GABAergic neurons of dorsolateral septum transmission,suggesting that TGR5 could be a novel target for developing antidepressants.
基金We thank Professor McGuckin M(MMRI,Brisbane)for providing human colon cancer cell lines(Caco-2,LoVo,and SW480)Dr.Rolfe B(AIBN,Brisbane)for providing mouse NSC-34 cells.
文摘BACKGROUND Colon cancer cell lines are widely used for research and for the screening of drugs that specifically target the stem cell compartment of colon cancers.It was reported that colon cancer carcinoma specimens contain a subset of leucine-rich repeatcontaining G protein-coupled receptor 5(LGR5)-expressing stem cells,these socalled“tumour-initiating”cells,reminiscent in their properties of the normal intestinal stem cells(ISCs),may explain the apparent heterogeneity of colon cancer cell lines.Also,colon cancer is initiated by aberrant Wnt signaling in ISCs known to express high levels of LGR5.Furthermore,in vivo reports demonstrate the clonal expansion of intestinal adenomas from a single LGR5-expressing cell.AIM To investigate whether colon cancer cell lines contain cancer stem cells and to characterize these putative cancer stem cells.METHODS A portable fluorescent reporter construct based on a conserved fragment of the LGR5 promoter was used to isolate the cell compartments expressing different levels of LGR5 in two widely used colon cancer cell lines(Caco-2 and LoVo).These cells were then characterized according to their proliferation capacity,gene expression signatures of ISC markers,and their tumorigenic properties in vivo and in vitro.RESULTS The data revealed that the LGR5 reporter can be used to identify and isolate a classical intestinal crypt stem cell-like population from the Caco-2,but not from the LoVo,cell lines,in which the cancer stem cell population is more akin to B lymphoma Moloney murine leukemia virus insertion region 1 homolog(+4 crypt)stem cells.This sub-population within Caco-2 cells exhibits an intestinal cancer stem cell gene expression signature and can both self-renew and generate differentiated LGR5 negative progeny.Our data also show that cells expressing high levels of LGR5/enhanced yellow fluorescent protein(EYFP)from this cell line exhibit tumorigenic-like properties in vivo and in vitro.In contrast,cell compartments of LoVo that are expressing high levels of LGR5/EYFP did not show these stem cell-like properties.Thus,cells that exhibit high levels of LGR5/EYFP expression represent the cancer stem cell compartment of Caco-2 colon cancer cells,but not LoVo cells.CONCLUSION Our findings highlight the presence of a spectrum of different ISC-like compartments in different colon cancer cell lines.Their existence is an important consideration for their screening applications and should be taken into account when interpreting drug screening data.We have generated a portable LGR5-reporter that serves as a valuable tool for the identification and isolation of different colon cancer stem cell populations in colon cancer lines.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFC1605000)National Natural Science Foundation of China(Grant No.31871806)the Beijing Livestock Industry Innovation Team(BAIC05-2023)。
文摘Milk fat globule membrane(MFGM),which contains abundant glycoproteins and phospholipids,exerts beneficial effects on intestinal health and immunomodulation.The aim of this study was to evaluate the protective effects and possible underlying mechanisms of MFGM on cow’s milk allergy(CMA)in aβ-lactoglobulin(BLG)-induced allergic mice model.MFGM was supplemented to allergic mice induced by BLG at a dose of 400 mg/kg body weight.Results demonstrated that MFGM alleviated food allergy symptoms,decreased serum levels of lipopolysaccharide,pro-inflammatory cytokines,immunoglobulin(Ig)E,Ig G1,and Th2 cytokines including interleukin(IL)-4,while increased serum levels of Th1 cytokines including interferon-γand regulatory T cells(Tregs)cytokines including IL-10 and transforming growth factor-β.MFGM modulated gut microbiota and enhanced intestinal barrier of BLG-allergic mice,as evidenced by decreased relative abundance of Desulfobacterota,Rikenellaceae,Lachnospiraceae,and Desulfovibrionaceae,while increased relative abundance of Bacteroidetes,Lactobacillaceae and Muribaculaceae,and enhanced expressions of tight junction proteins including Occludin,Claudin-1 and zonula occludens-1.Furthermore,MFGM increased fecal short-chain fatty acids(SCFAs)levels,which elevated G protein-coupled receptor(GPR)43 and GPR109A expressions.The increased expressions of GPR43 and GPR109A induced CD103+dendritic cells accumulation and promoted Tregs differentiation in mesenteric lymph node to a certain extent.In summary,MFGM alleviated CMA in a BLG-induced allergic mice model through enhancing intestinal barrier and promoting Tregs differentiation,which may be correlated with SCFAs-mediated activation of GPRs.These findings suggest that MFGM may be useful as a promising functional ingredient against CMA.
基金University of Missouri,Postdoctoral Research Award.
文摘Nonalcoholic fatty liver disease(NAFLD)is a broad-spectrum disease,ranging from simple hepatic steatosis to nonalcoholic steatohepatitis,which can progress to cirrhosis and liver cancer.Abnormal hepatic lipid accumulation is the major manifestation of this disease,and lipotoxicity promotes NAFLD progression.In addition,intermediate metabolites such as succinate can stimulate the activation of hepatic stellate cells to produce extracellular matrix proteins,resulting in progression of NAFLD to fibrosis and even cirrhosis.G protein-coupled receptors(GPCRs)have been shown to play essential roles in metabolic disorders,such as NAFLD and obesity,through their function as receptors for bile acids and free fatty acids.In addition,GPCRs link gut microbiota-mediated connections in a variety of diseases,such as intestinal diseases,hepatic steatosis,diabetes,and cardiovascular diseases.The latest findings show that gut microbiota-derived acetate contributes to liver lipogenesis by converting dietary fructose into hepatic acetyl-CoA and fatty acids.GPCR agonists,including peptides and natural products like docosahexaenoic acid,have been applied to investigate their role in liver diseases.Therapies such as probiotics and GPCR agonists may be applied to modulate GPCR function to ameliorate liver metabolism syndrome.This review summarizes the current findings regarding the role of GPCRs in the development and progression of NAFLD and describes some preclinical and clinical studies of GPCR-mediated treatment.Overall,understanding GPCR-mediated signaling in liver disease may provide new therapeutic options for NAFLD.
文摘With the high prevalence of obesity, diabetes, and otherfeatures of the metabolic syndrome in United States, nonalcoholic fatty liver disease(NAFLD) has inevitably become a very prevalent chronic liver disease and is now emerging as one of the leading indications for liver transplantation. Insulin resistance and derangement of lipid metabolism, accompanied by activation of the pro-inflammatory response and fibrogenesis, are essential pathways in the development of the more clinically significant form of NAFLD, known as nonalcoholic steatohepatitis(NASH). Recent advances in the functional characterization of bile acid receptors, such as farnesoid X receptor(FXR) and transmembrane G protein-coupled receptor(TGR) 5, have provided further insight in the pathophysiology of NASH and have led to the development of potential therapeutic targets for NAFLD and NASH. Beyond maintaining bile acid metabolism, FXR and TGR5 also regulate lipid metabolism, maintain glucose homeostasis, increase energy expenditure, and ameliorate hepatic inflammation. These intriguing features have been exploited to develop bile acid analogues to target pathways in NAFLD and NASH pathogenesis. This review provides a brief overview of the pathogenesis of NAFLD and NASH, and then delves into the biological functions of bile acid receptors, particularly with respect to NASH pathogenesis, with a description of the associated experimental data, and, finally, we discuss the prospects of bile acid analogues in the treatment of NAFLD and NASH.
基金Supported by National Science and Technology Major Project of China,No.2018ZX10302206.
文摘The intensive crosstalk between the liver and the intestine performs many essential functions.This crosstalk is important for natural immune surveillance,adaptive immune response regulation and nutrient metabolism and elimination of toxic bacterial metabolites.The interaction between the gut microbiome and bile acids is bidirectional.The gut microbiome regulates the synthesis of bile acids and their biological signaling activity and circulation via enzymes.Similarly,bile acids also shape the composition of the gut microbiome by modulating the host’s natural antibacterial defense and the intestinal immune system.The interaction between bile acids and the gut microbiome has been implicated in the pathophysiology of many intestinal and extra intestinal diseases,especially liver diseases.As essential mediators of the gut-liver crosstalk,bile acids regulate specific host metabolic pathways and modulate the inflammatory responses through farnesoid X-activated receptor and G protein-coupled bile acid receptor 1.Several clinical trials have demonstrated the signaling effects of bile acids in the context of liver diseases.We hypothesize the existence of a gut microbiome-bile acids-liver triangle and explore the potential therapeutic strategies for liver diseases targeting the triangle.
文摘Recent studies have revealed that bile acids(BAs)are not only facilitators of dietary lipid absorption but also important signaling molecules exerting multiple physiological functions.Some major signaling pathways involving the nuclear BAs receptor farnesoid X receptor and the G protein-coupled BAs receptor TGR5/M-BAR have been identified to be the targets of BAs.BAs regulate their own homeostasis via signaling pathways.BAs also affect diverse metabolic pathways including glucose metabolism,lipid metabolism and energy expenditure.This paper suggests the mechanism of controlling metabolism via BA signaling and demonstrates that BA signaling is an attractive therapeutic target of the metabolic syndrome.
基金Supported by National Key Technology Support Program during“12th Five-Year Plan”Period of China,No.2014BAI08B00National Key Research and Development Plan for Precision Medicine Research,No.2017YFC0910002and Leapforward Development Program for Beijing Biopharmaceutical Industry(G20),No.Z171100001717008.
文摘BACKGROUND Gut microbiota and its metabolites may be involved in the pathogenesis of inflammatory bowel disease.Several clinical studies have recently shown that patients with ulcerative colitis(UC)have altered profiles of fecal bile acids(BAs).It was observed that BA receptors Takeda G-protein-coupled receptor 5(TGR5)and vitamin D receptor(VDR)participate in intestinal inflammatory responses by regulating NF-ĸB signaling.We hypothesized that altered profiles of fecal BAs might be correlated with gut microbiota and inflammatory responses in patients with UC.AIM To investigate the changes in fecal BAs and analyze the relationship of BAs with gut microbiota and inflammation in patients with UC.METHODS The present study used 16S rDNA sequencing technology to detect the differences in the intestinal flora between UC patients and healthy controls(HCs).Fecal BAs were measured by targeted metabolomics approaches.Mucosal TGR5 and VDR expression was analyzed using immunohistochemistry,and serum inflammatory cytokine levels were detected by ELISA.RESULTS Thirty-two UC patients and twenty-three HCs were enrolled in this study.It was found that the diversity of gut microbiota in UC patients was reduced compared with that in HCs.Firmicutes,Clostridium IV,Butyricicoccus,Clostridium XlVa,Faecalibacterium,and Roseburia were significantly decreased in patients with UC(P=3.75E-05,P=8.28E-07,P=0.0002,P=0.003,P=0.0003,and P=0.0004,respectively).Proteobacteria,Escherichia,Enterococcus,Klebsiella,and Streptococcus were significantly enriched in the UC group(P=2.99E-09,P=3.63E-05,P=8.59E-05,P=0.003,and P=0.016,respectively).The concentrations of fecal secondary BAs,such as lithocholic acid,deoxycholic acid,glycodeoxycholic acid,glycolithocholic acid,and taurolithocholate,in UC patients were significantly lower than those in HCs(P=8.1E-08,P=1.2E-07,P=3.5E-04,P=1.9E-03,and P=1.8E-02,respectively)and were positively correlated with Butyricicoccus,Roseburia,Clostridium IV,Faecalibacterium,and Clostridium XlVb(P<0.01).The concentrations of primary BAs,such as taurocholic acid,cholic acid,taurochenodeoxycholate,and glycochenodeoxycholate,in UC patients were significantly higher than those in HCs(P=5.3E-03,P=4E-02,P=0.042,and P=0.045,respectively)and were positively related to Enterococcus,Klebsiella,Streptococcus,Lactobacillus,and pro-inflammatory cytokines(P<0.01).The expression of TGR5 was significantly elevated in UC patients(0.019±0.013 vs 0.006±0.003,P=0.0003).VDR expression in colonic mucosal specimens was significantly decreased in UC patients(0.011±0.007 vs 0.016±0.004,P=0.033).CONCLUSION Fecal BA profiles are closely related to the gut microbiota and serum inflammatory cytokines.Dysregulation of the gut microbiota and altered constitution of fecal BAs may participate in regulating inflammatory responses via the BA receptors TGR5 and VDR.
文摘BACKGROUND In the heart,aldosterone(Aldo)binds the mineralocorticoid receptor(MR)to exert damaging,adverse remodeling-promoting effects.We recently showed that G protein-coupled receptor-kinase(GRK)-5 blocks the cardiac MR by directly phosphorylating it,thereby repressing its transcriptional activity.MR antagonist(MRA)drugs block the cardiac MR reducing morbidity and mortality of advanced human heart failure.Non-steroidal MRAs,such as finerenone,may provide better cardio-protection against Aldo than classic,steroidal MRAs,like spironolactone and eplerenone.AIM To investigate potential differences between finerenone and eplerenone at engaging GRK5-dependent cardiac MR phosphorylation and subsequent blockade.METHODS We used H9c2 cardiomyocytes,which endogenously express the MR and GRK5.RESULTS GRK5 phosphorylates the MR in H9c2 cardiomyocytes in response to finerenone but not to eplerenone.Unlike eplerenone,finerenone alone potently and efficiently suppresses cardiac MR transcriptional activity,thus displaying inverse agonism.GRK5 is necessary for finerenone’s inverse agonism,since GRK5 genetic deletion renders finerenone incapable of blocking cardiac MR transcriptional activity.Eplerenone alone does not fully suppress cardiac MR basal activity regardless of GRK5 expression levels.Finally,GRK5 is necessary for the antiapoptotic,anti-oxidative,and anti-fibrotic effects of both finerenone and eplerenone against Aldo,as well as for the higher efficacy and potency of finerenone at blocking Aldo-induced apoptosis,oxidative stress,and fibrosis.CONCLUSION Finerenone,but not eplerenone,induces GRK5-dependent cardiac MR inhibition,which underlies,at least in part,its higher potency and efficacy,compared to eplerenone,as an MRA in the heart.GRK5 acts as a co-repressor of the cardiac MR and is essential for efficient MR antagonism in the myocardium.
基金supported by the National Science Fund for Distinguished Young Scholars(#82225008,China)the National Natural Science Foundation of China(#82070608)+1 种基金the Anhui Provincial Natural Science Foundation(#2108085Y28,China)the Research Improvement Program of Anhui Medical University(#2019xkjT007,China).
文摘Nonalcoholic fatty liver disease(NAFLD)is the most common chronic liver disease worldwide.Fat accumulation“sensitizes”the liver to insult and leads to nonalcoholic steatohepatitis(NASH).G protein-coupled receptor 35(GPR35)is involved in metabolic stresses,but its role in NAFLD is unknown.We report that hepatocyte GPR35 mitigates NASH by regulating hepatic cholesterol homeostasis.Specifically,we found that GPR35 overexpression in hepatocytes protected against high-fat/cholesterol/fructose(HFCF)diet-induced steatohepatitis,whereas loss of GPR35 had the opposite effect.Administration of the GPR35 agonist kynurenic acid(Kyna)suppressed HFCF diet-induced steatohepatitis in mice.Kyna/GPR35 induced expression of StAR-related lipid transfer protein 4(STARD4)through the ERK1/2 signaling pathway,ultimately resulting in hepatic cholesterol esterification and bile acid synthesis(BAS).The overexpression of STARD4 increased the expression of the BAS rate-limiting enzymes cytochrome P450 family 7 subfamily A member 1(CYP7A1)and CYP8B1,promoting the conversion of cholesterol to bile acid.The protective effect induced by GPR35 overexpression in hepatocytes disappeared in hepatocyte STARD4-knockdown mice.STARD4 overexpression in hepatocytes reversed the aggravation of HFCF diet-induced steatohepatitis caused by the loss of GPR35 expression in hepatocytes in mice.Our findings indicate that the GPR35–STARD4 axis is a promising therapeutic target for NAFLD.
基金supported by VA Merit Award 5I01BX005730NIH 1R01AA030180,2R56DK115377-05A1.
文摘Maintaining bile acid homeostasis is essential for metabolic health.Bile acid homeostasis encompasses a complex interplay between biosynthesis,conjugation,secretion,and reabsorption.Beyond their vital role in digestion and absorption of lipid-soluble nutrients,bile acids are pivotal in systemic metabolic regulation.Recent studies have linked bile acid dysregulation to the pathogenesis of metabolic diseases,including obesity,type 2 diabetes melli-tus(T2DM),and metabolic dysfunction-associated steatotic liver disease(MASLD).Bile acids are essential signaling molecules that regulate many critical biological processes,including lipid metabolism,energy expenditure,insulin sensitivity,and glucose metabolism.Disruption in bile acid homeostasis contributes to metabolic disease via altered bile acid feedback mechanisms,hormonal dysregu-lation,interactions with the gut microbiota,and changes in the expression and function of bile acid transporters and receptors.This review summarized the essential molecular pathways and regulatory mechanisms through which bile acid dysregulation contributes to the pathogenesis and progression of obesity,T2DM,and MASLD.We aim to underscore the significance of bile acids as potential diag-nostic markers and therapeutic agents in the context of metabolic diseases,providing insights into their application in translational medicine.
文摘Objective： To investigate Leucine-rich repeat-containing G protein-coupled receptor 5 （LGR5） expressions in gastric cancer and to evaluate its clinical significance. Methods： LGR5 expression was assessed by immunohistochemistry in 257 gastric cancer patients after surgery. The relationships between LGR5 expression and clinicopathological features and patients prognosis were statistically analyzed. Results： The expression of LGR5 was significantly higher in gastric cancers as a cancer stem cell marker than in adjacent normal tissues （P〈0.001）, and more frequently in patients with intestinal type, well-moderate differentiation and stage I and II （P〈0.05）. Although we found gastric cancer patients with LGR5 positive expression had a poorer prognosis, it didn＇t meet statistical significance （P〉0.05）. LGR5 negative expression was significantly related to the favorable overall survival in stage I and II gastric cancer patients （P〈0.05）. Furthermore, patients with high LGR5 expression tended to be more likely to get progression and have poorer progress-free survival （P〈0.05）. Multivariate Cox regression analysis revealed that LGR5 expression was an independent factor of overall survival for the patients with stage I and II gastric cancer （P〈0.05）. Conclusions： Our results show that LGR5 may play an important role in tumorigenesis and progression and would be a powerful marker to predict the prognosis of patients with stage I and II gastric cancer.
基金Supported by A grant from the Beijing Municipal Science and Technology Commission’s NOVA Program,No.2009BG-02Beijing Municipal Health System Special funds of High-Level Medical Personnel Construction,No.2013-3-082
文摘AIM:To investigate the differential expression of leu-cine-rich repeat-containing G protein-coupled receptor5(LGR5)in gastric cancer tissues and its significance related to tumor growth and spread.METHODS:Formalin-fixed biopsy specimens of intestinal metaplasia(n=90),dysplasia(n=53),gastric adenocarcinoma(n=180),metastases in lymph nodes and the liver(n=15),and lesion-adjacent normal gastric mucosa(controls;n=145)were obtained for analysis from the Peking University Cancer Hospital’s Department of Pathology and Gastrointestinal Surgery tissue archives(January 2003 to December 2011).The biopsied patients’demographic and clinicopathologic data were retrieved from the hospital’s medical records database.Each specimen was subjected to histopathological typing to classify the tumor node metastasis(TNM)stage and to immunohistochemistry staining to detect the expression of the cancer stem cell marker LGR5.The intergroup differences in LGR5 expression were assessed by Spearman’s rank correlation analysis,and the relationship between LGR5 expression level and the patients’clinicopathological characteristics was evaluated by theχ2test or Fisher’s exact test.RESULTS:Significantly more gastric cancer tissues showed LGR5+staining than normal control tissues(all P<0.01),with immunoreactivity detected in 72.2%(65/90)and 50.9%(27/53)of intestinal metaplasia and dysplasia specimens,respectively,52.8%(95/180)of gastric adenocarcinoma specimens,and 73.3%%(11/15)of metastasis specimens,but 26.9%(39/145)of lesion-adjacent normal gastric mucosa specimens.Comparison of the intensity of LGR5+staining showed an increasing trend that generally followed increasing dedifferentiation and tumor spread(normal tissue<dysplasia,<gastric adenocarcinoma<metastasis;all P<0.001),with the exception of expression level detected in intestinal metaplasia which was higher than that in normal gastric tissues(P<0.001).Moreover,gastric cancer-associated enhanced expression of LGR5 was found to be signifcantly associated with age,tumor differentiation,Lauren type and TNM stage(Ⅰ+ⅡvsⅢ+Ⅳ)(all P<0.05),but not with sex,tumor site,location,size,histology,lymphovascular invasion,depth of invasion,lymph node metastasis or distant metastasis.Patients with LGR5+gastric cancer specimens and without signs of metastasis from the original biopsy experienced more frequent rates of recurrence or metastasis during follow-up than patients with LGR5-specimens(P<0.05).CONCLUSION:Enhanced LGR5 is related to progressive dedifferentiation and metastasis of gastric cancer,indicating the potential of this receptor as an early diagnostic and prognostic biomarker.
