Cholesterol 7 alpha-hydroxylase(CYP7A1,EC1.14)is the first and rate-limiting enzyme in the classic bile acid synthesis pathway.Much progress has been made in understanding the transcriptional regulation of CYP7A1 gene...Cholesterol 7 alpha-hydroxylase(CYP7A1,EC1.14)is the first and rate-limiting enzyme in the classic bile acid synthesis pathway.Much progress has been made in understanding the transcriptional regulation of CYP7A1 gene expression and the underlying molecular mechanisms of bile acid feedback regulation of CYP7A1 and bile acid synthesis in the last three decades.Discovery of bile acid-activated receptors and their roles in the regulation of lipid,glucose and energy metabolism have been translated to the development of bile acid-based drug therapies for the treatment of liver-related metabolic diseases such as alcoholic and non-alcoholic fatty liver diseases,liver cirrhosis,diabetes,obesity and hepatocellular carcinoma.This review will provide an update on the advances in our understanding of the molecular biology and mechanistic insights of the regulation of CYP7A1 in bile acid synthesis in the last 40 years.展开更多
AIM To compare transcriptomes of non-alcoholic fatty liver disease(NAFLD) and alcoholic liver disease(ALD) in a meta-analysis of liver biopsies.METHODS Employing transcriptome data from patient liver biopsies retrieve...AIM To compare transcriptomes of non-alcoholic fatty liver disease(NAFLD) and alcoholic liver disease(ALD) in a meta-analysis of liver biopsies.METHODS Employing transcriptome data from patient liver biopsies retrieved from several public repositories we performed a meta-analysis comparing ALD and NAFLD.RESULTS We observed predominating commonalities at the transcriptome level between ALD and NAFLD,most prominently numerous down-regulated metabolic pathways and cytochrome-related pathways and a few up-regulated pathways which include ECM-receptor interaction,phagosome and lysosome.However some pathways were regulated in opposite directions in ALD and NAFLD,for example,glycolysis was down-regulated in ALD and up-regulated in NAFLD.Interestingly,we found rate-limiting genes such as HMGCR,SQLE and CYP7A1 which are associated with cholesterol processes adversely regulated between ALD(down-regulated) and NAFLD(up-regulated).We propose that similar phenotypes in both diseases may be due to a lower level of the enzyme CYP7A1 compared to the cholesterol synthesis enzymes HMGCR and SQLE.Additionally,we provide a compendium of comparative KEGG pathways regulation in ALD and NAFLD.CONCLUSION Our finding of adversely regulated cholesterol processes in ALD and NAFLD draws the focus to regulation of cholesterol secretion into bile.Thus,it will be interesting to further investigate CYP7A1-mediated cholesterol secretion into bile-also as possible drug targets.The list of potential novel biomarkers may assist differential diagnosis of ALD and NAFLD.展开更多
Farnesoid X receptor(FXR) is a member of the nuclear receptor superfamily of ligand-activated transcription factors.As a metabolic regulator,FXR plays key roles in bile acid and cholesterol metabolism and lipid and gl...Farnesoid X receptor(FXR) is a member of the nuclear receptor superfamily of ligand-activated transcription factors.As a metabolic regulator,FXR plays key roles in bile acid and cholesterol metabolism and lipid and glucose homeostasis.Therefore,FXR is a potential drug target for several metabolic syndromes,especially those related to lipidemia disorders.In the present study,we identified small molecule SIPI-7623,a derivative of an extract from Oriental wormwood(Artemisia capillaris),and found that it specifically upregulated the expression of cholesterol-7-alpha-hydroxylase(CYP7 A1),downregulated the expression of sterol-regulatory element-binding protein 1 c(SREBP-1 c) in the liver,and inhibited the expression of ileal bile acid binding-protein(IBABP) in the ileum of rats.We found that inhibition of FXR by SIPI-7623 decreased the level of cholesterol and triglyceride.SIPI-7623 reduced the levels of cholesterol and triglyceride in in vitro Hep G2 cell models,ameliorated diet-induced atherosclerosis,and decreased the serum lipid content on rats and rabbits model of atherosclerosis in vivo.Furthermore,SIPI-7623 decreased the extent of atherosclerotic lesions.Our resutls demonstrated that antagonism of the FXR pathway can be employed as a therapeutic strategy to treat metabolic diseases such as hyperlipidemia and atherosclerosis.In conclusion,SIPI-7623 could be a promising lead compound for development of drugs to treat hyperlipidemia and atherosclerosis.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
Plasma lipids are controlled by genes and play an important role in the development of atherosclerosis. Dysplipidemia is an important risk factor for coronary artery disease (CAD). Coronary artery disease is the leadi...Plasma lipids are controlled by genes and play an important role in the development of atherosclerosis. Dysplipidemia is an important risk factor for coronary artery disease (CAD). Coronary artery disease is the leading cause of mortality and morbidity in the developed world. More than 14 million Americans are afflicted with clinically significant CAD.~1 To illustrate the impact of CAD in developed countries, the medical and societal costs of CAD in the United States alone are in excess of $90 billion annually.~1 More than (600 000) Americans each year develop new cardiac events, more than 10% of which occur in Americans (<50) years of age.~1 Identifying genetic predisposition to early onset of CAD could help in understanding basic disease mechanism, guiding targeted preventive efforts, and planning appropriate therapeutic strategies.展开更多
文摘目的:探讨胆固醇结石(GS)小鼠肝脏的核受体基因——肝核受体类似物1(liver receptor homolog 1,LRH-1)及其调控基因胆固醇7α-羟化酶(cholesterol 7-αhydroxylase,CYP7A1)的表达。方法:雌性C57BL/6小鼠40只,分为2组,每组20只,分别予以正常饮食、高脂饮食喂养10周后处死。病理切片检查小鼠胆囊壁细胞组织学改变,实时定量PCR法测定肝脏LRH-1及CYP7A1表达量。Western Blot方法测定肝脏上述基因蛋白的表达量。结果:胆结石小鼠胆囊壁细胞呈现炎性改变。胆石组小鼠LRH-1 m RNA及蛋白表达均高于对照组(P<0.01),CYP7A1 m RNA及蛋白表达量较对照组升高(P<0.01)。结论:啮齿动物肝脏LRH-1和CYP7A1的表达异常与胆囊胆固醇结石形成有关,可能共同在小鼠胆结石形成中发挥作用。
基金This research is supported by grants DK58379 and DK44442 from the USA National Institute of Diabetes and Digestive and Kidney Diseases,National Institutes of Health.
文摘Cholesterol 7 alpha-hydroxylase(CYP7A1,EC1.14)is the first and rate-limiting enzyme in the classic bile acid synthesis pathway.Much progress has been made in understanding the transcriptional regulation of CYP7A1 gene expression and the underlying molecular mechanisms of bile acid feedback regulation of CYP7A1 and bile acid synthesis in the last three decades.Discovery of bile acid-activated receptors and their roles in the regulation of lipid,glucose and energy metabolism have been translated to the development of bile acid-based drug therapies for the treatment of liver-related metabolic diseases such as alcoholic and non-alcoholic fatty liver diseases,liver cirrhosis,diabetes,obesity and hepatocellular carcinoma.This review will provide an update on the advances in our understanding of the molecular biology and mechanistic insights of the regulation of CYP7A1 in bile acid synthesis in the last 40 years.
基金Supported by The Medical Faculty of the Heinrich Heine University Düsseldorf
文摘AIM To compare transcriptomes of non-alcoholic fatty liver disease(NAFLD) and alcoholic liver disease(ALD) in a meta-analysis of liver biopsies.METHODS Employing transcriptome data from patient liver biopsies retrieved from several public repositories we performed a meta-analysis comparing ALD and NAFLD.RESULTS We observed predominating commonalities at the transcriptome level between ALD and NAFLD,most prominently numerous down-regulated metabolic pathways and cytochrome-related pathways and a few up-regulated pathways which include ECM-receptor interaction,phagosome and lysosome.However some pathways were regulated in opposite directions in ALD and NAFLD,for example,glycolysis was down-regulated in ALD and up-regulated in NAFLD.Interestingly,we found rate-limiting genes such as HMGCR,SQLE and CYP7A1 which are associated with cholesterol processes adversely regulated between ALD(down-regulated) and NAFLD(up-regulated).We propose that similar phenotypes in both diseases may be due to a lower level of the enzyme CYP7A1 compared to the cholesterol synthesis enzymes HMGCR and SQLE.Additionally,we provide a compendium of comparative KEGG pathways regulation in ALD and NAFLD.CONCLUSION Our finding of adversely regulated cholesterol processes in ALD and NAFLD draws the focus to regulation of cholesterol secretion into bile.Thus,it will be interesting to further investigate CYP7A1-mediated cholesterol secretion into bile-also as possible drug targets.The list of potential novel biomarkers may assist differential diagnosis of ALD and NAFLD.
基金supported by Shanghai Committee of Science and Technology(No.16431903500)
文摘Farnesoid X receptor(FXR) is a member of the nuclear receptor superfamily of ligand-activated transcription factors.As a metabolic regulator,FXR plays key roles in bile acid and cholesterol metabolism and lipid and glucose homeostasis.Therefore,FXR is a potential drug target for several metabolic syndromes,especially those related to lipidemia disorders.In the present study,we identified small molecule SIPI-7623,a derivative of an extract from Oriental wormwood(Artemisia capillaris),and found that it specifically upregulated the expression of cholesterol-7-alpha-hydroxylase(CYP7 A1),downregulated the expression of sterol-regulatory element-binding protein 1 c(SREBP-1 c) in the liver,and inhibited the expression of ileal bile acid binding-protein(IBABP) in the ileum of rats.We found that inhibition of FXR by SIPI-7623 decreased the level of cholesterol and triglyceride.SIPI-7623 reduced the levels of cholesterol and triglyceride in in vitro Hep G2 cell models,ameliorated diet-induced atherosclerosis,and decreased the serum lipid content on rats and rabbits model of atherosclerosis in vivo.Furthermore,SIPI-7623 decreased the extent of atherosclerotic lesions.Our resutls demonstrated that antagonism of the FXR pathway can be employed as a therapeutic strategy to treat metabolic diseases such as hyperlipidemia and atherosclerosis.In conclusion,SIPI-7623 could be a promising lead compound for development of drugs to treat hyperlipidemia and atherosclerosis.
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.
文摘Plasma lipids are controlled by genes and play an important role in the development of atherosclerosis. Dysplipidemia is an important risk factor for coronary artery disease (CAD). Coronary artery disease is the leading cause of mortality and morbidity in the developed world. More than 14 million Americans are afflicted with clinically significant CAD.~1 To illustrate the impact of CAD in developed countries, the medical and societal costs of CAD in the United States alone are in excess of $90 billion annually.~1 More than (600 000) Americans each year develop new cardiac events, more than 10% of which occur in Americans (<50) years of age.~1 Identifying genetic predisposition to early onset of CAD could help in understanding basic disease mechanism, guiding targeted preventive efforts, and planning appropriate therapeutic strategies.
