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
Obeticholic acid(OCA), the first FXR-targeting drug, has been claimed effective in the therapy of liver fibrosis. However, recent clinical trials indicated that OCA might not be effective against liver fibrosis, possi...Obeticholic acid(OCA), the first FXR-targeting drug, has been claimed effective in the therapy of liver fibrosis. However, recent clinical trials indicated that OCA might not be effective against liver fibrosis, possibly due to the lower dosage to reduce the incidence of the side-effect of pruritus. Here we propose a combinatory therapeutic strategy of OCA and apoptosis inhibitor for combating against liver fibrosis. CCl4-injured mice, D-galactosamine/LPS(GalN/LPS)-treated mice and cycloheximide/TNFα(CHX/TNFα)-treated HepG2 cells were employed to assess the effects of OCA, or together with IDN-6556, an apoptosis inhibitor. OCA treatment significantly inhibited hepatic stellate cell(HSC)activation/proliferation and prevented fibrosis. Elevated bile acid(BA) levels and hepatocyte apoptosis triggered the activation and proliferation of HSCs. OCA treatment reduced BA levels but could not inhibit hepatocellular apoptosis. An enhanced anti-fibrotic effect was observed when OCA was co-administrated with IDN-6556. Our study demonstrated that OCA inhibits HSCs activation/proliferation partially by regulating BA homeostasis and thereby inhibiting activation of HSCs. The findings in this study suggest that combined use of apoptosis inhibitor and OCA at lower dosage represents a novel therapeutic strategy for liver fibrosis.展开更多
Bile acids(BAs) are essential for the absorption of lipids. BA synthesis is inhibited through intestinal farnesoid X receptor(FXR) activity. BA sequestration is known to influence BA metabolism and control serum lipid...Bile acids(BAs) are essential for the absorption of lipids. BA synthesis is inhibited through intestinal farnesoid X receptor(FXR) activity. BA sequestration is known to influence BA metabolism and control serum lipid concentrations. Animal data has demonstrated a regulatory role for the FXR in triglyceride metabolism. FXR inhibits hepatic lipogenesis by inhibiting the expression of sterol regulatory element binding protein 1c via small heterodimer primer activity. Conversely, FXR promotes free fatty acids oxidation by inducing the expression of peroxisome proliferator-activated receptor α. FXR can reduce the expression of microsomal triglyceride transfer protein, which regulates the assembly of very low-density lipoproteins(VLDL). FXR activation in turn promotes the clearance of circulating triglycerides by inducing apolipoprotein C-Ⅱ, very low-density lipoproteins receptor(VLDL-R) and the expression of Syndecan-1 together with the repression of apolipoprotein C-Ⅲ, which increases lipoprotein lipase activity. There is currently minimal clinical data on triglyceride metabolism in patients with bile acid diarrhoea(BAD). Emerging data suggests that a third of patients with BAD have hypertriglyceridemia. Further research is required to establish the risk of hypertriglyceridaemia in patients with BAD and elicit the mechanisms behind this, allowing for targeted treatment.展开更多
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 Natural Science Foundation of China (grants 81430091, 81720108032, 81421005, 91429308 and 81603194)the Project for Major New Drug Innovation and Development (grant 2015ZX09501010 and 2017ZX09101003-002-003, China)+3 种基金Overseas Expertise Introduction Project for Discipline Innovation (G20582017001, China)"Double First Class" Initiative Project (CPU2018GF01 and CPU2018GF09, China)State Key Laboratory of Natural Medicines at China Pharmaceutical University (SKLNMZZCX201610 and SKLNMZZCX201801, China)China Postdoctoral Science Foundation (grants 2016M600455 and 2017T100423)
文摘Obeticholic acid(OCA), the first FXR-targeting drug, has been claimed effective in the therapy of liver fibrosis. However, recent clinical trials indicated that OCA might not be effective against liver fibrosis, possibly due to the lower dosage to reduce the incidence of the side-effect of pruritus. Here we propose a combinatory therapeutic strategy of OCA and apoptosis inhibitor for combating against liver fibrosis. CCl4-injured mice, D-galactosamine/LPS(GalN/LPS)-treated mice and cycloheximide/TNFα(CHX/TNFα)-treated HepG2 cells were employed to assess the effects of OCA, or together with IDN-6556, an apoptosis inhibitor. OCA treatment significantly inhibited hepatic stellate cell(HSC)activation/proliferation and prevented fibrosis. Elevated bile acid(BA) levels and hepatocyte apoptosis triggered the activation and proliferation of HSCs. OCA treatment reduced BA levels but could not inhibit hepatocellular apoptosis. An enhanced anti-fibrotic effect was observed when OCA was co-administrated with IDN-6556. Our study demonstrated that OCA inhibits HSCs activation/proliferation partially by regulating BA homeostasis and thereby inhibiting activation of HSCs. The findings in this study suggest that combined use of apoptosis inhibitor and OCA at lower dosage represents a novel therapeutic strategy for liver fibrosis.
基金the BRET (Bardhan Research Education Trust) charity, which has supported funding for materials and equipment costs
文摘Bile acids(BAs) are essential for the absorption of lipids. BA synthesis is inhibited through intestinal farnesoid X receptor(FXR) activity. BA sequestration is known to influence BA metabolism and control serum lipid concentrations. Animal data has demonstrated a regulatory role for the FXR in triglyceride metabolism. FXR inhibits hepatic lipogenesis by inhibiting the expression of sterol regulatory element binding protein 1c via small heterodimer primer activity. Conversely, FXR promotes free fatty acids oxidation by inducing the expression of peroxisome proliferator-activated receptor α. FXR can reduce the expression of microsomal triglyceride transfer protein, which regulates the assembly of very low-density lipoproteins(VLDL). FXR activation in turn promotes the clearance of circulating triglycerides by inducing apolipoprotein C-Ⅱ, very low-density lipoproteins receptor(VLDL-R) and the expression of Syndecan-1 together with the repression of apolipoprotein C-Ⅲ, which increases lipoprotein lipase activity. There is currently minimal clinical data on triglyceride metabolism in patients with bile acid diarrhoea(BAD). Emerging data suggests that a third of patients with BAD have hypertriglyceridemia. Further research is required to establish the risk of hypertriglyceridaemia in patients with BAD and elicit the mechanisms behind this, allowing for targeted treatment.
文摘目的探讨雌激素受体α(estrogen receptorα,ERα)对参与调节胆汁酸转运相关的基因,如法尼醇X受体(farnesoid X receptor,FXR)、钠离子-牛磺胆酸共转运蛋白(sodium taurocholate co-transprorting polypeptide,NTCP)、胆盐输出泵(bile salt export pump,BSEP)的调控作用及其对孕鼠肝内胆汁淤积发生的影响。方法将40只SPF级SD孕鼠随机均分为4组。自孕第15 d起,对照组颈部皮下注射精制植物油2.0 m L/kg·d;低、中、高剂量组分别皮下注射17α-乙炔雌二醇1.0 mg/kg·d、1.25 mg/kg·d、1.5 mg/kg·d。于妊娠第21 d采血2 m L,后采用颈部脱臼法处死,提取母鼠肝脏行活体组织学检查。检测各组孕鼠血清中的生化指标及肝脏组织中各目的蛋白和mRNA表达量。结果生化指标:低、中、高剂量组孕鼠各蛋白表达水平明显高于对照组,差异有统计学意义(P<0.05),低、中、高剂量组组间比较,差异有统计学意义(P<0.05);蛋白表达及mRNA的表达水平:ER在对照组、低剂量组、中剂量组、高剂量组的表达量依次升高,而FXR、NTCP、BSEP在对照组、低剂量组、中剂量组、高剂量组的表达量依次降低,各组目的基因表达量与对照组比较,差异均有统计学意义(P<0.05)。结论随着雌激素剂量的增加,ERα表达水平升高,而FXR、NTCP、BSEP表达水平均降低,提示胆汁酸代谢转运功能降低,可能为雌激素诱导孕鼠肝内胆汁淤积的发生机制之一。
