Background Genetic factors account for approximately 50% of the individual variation in plasma low-density lipoprotein cholesterol (LDL-C) concentrations in the general population. Several candidate genes have been pr...Background Genetic factors account for approximately 50% of the individual variation in plasma low-density lipoprotein cholesterol (LDL-C) concentrations in the general population. Several candidate genes have been proposed but their relative contributions to the variance in LDL-C are not known, except for apolipoprotein E (apoE). We report here an investigation of the relationship between LDL-C and cholesterol 7α-hydroxylase (CYP7), as well as apoE and low-density lipoprotein receptor (LDLR), three pivotal genes in LDL metabolism. Methods Our study population included more than 200 nuclear families with increased coronary heart disease (CHD) risk from the National Heart, Lung, and Blood Institute (NHLBI) Family Heart Study. Variance-component linkage methods, a measured genotype approach, and a variance-component linkage analysis conditional on a measured genotype association were used. Results The results showed significant linkage between a genetic determinant of plasma LDL-C concentrations and a polymorphism near CYP7 with its allelic variation accounting for 27% of the total LDL-C variation. There is significant association between plasma LDL-C concentrations and apoE genotypes. Conditional on the apoE association, the total LDL-C variation accounted by allelic variation of a polymorphism near CYP7 was increased significantly.Conclusion Our results suggest the apoE and CYP7 may be two important genes accounting for the genetic variation of plasma LDL-C concentrations in a population with cardiovascular diseases.展开更多
Since metabolic process differs between humans and mice, studies were performed in hamsters, which are generally considered to be a more appropriate animal model for studies of obesityrelated metabolic disorders. The ...Since metabolic process differs between humans and mice, studies were performed in hamsters, which are generally considered to be a more appropriate animal model for studies of obesityrelated metabolic disorders. The modulation of gut microbiota, bile acids and the farnesoid X receptor(FXR) axis is correlated with obesity-induced insulin resistance and hepatic steatosis in mice. However,the interactions among the gut microbiota, bile acids and FXR in metabolic disorders remained largely unexplored in hamsters. In the current study, hamsters fed a 60% high-fat diet(HFD) were administeredvehicle or an antibiotic cocktail by gavage twice a week for four weeks. Antibiotic treatment alleviated HFD-induced glucose intolerance, hepatic steatosis and inflammation accompanied with decreased hepatic lipogenesis and elevated thermogenesis in subcutaneous white adipose tissue(sWAT). In the livers of antibiotic-treated hamsters, cytochrome P450 family 7 subfamily B member 1(CYP7 B1) in the alternative bile acid synthesis pathway was upregulated, contributing to a more hydrophilic bile acid profile with increased tauro-β-muricholic acid(TβMCA). The intestinal FXR signaling was suppressed but remained unchanged in the liver. This study is of potential translational significance in determining the role of gut microbiota-mediated bile acid metabolism in modulating diet-induced glucose intolerance and hepatic steatosis in the hamster.展开更多
AIM: To determine the possible association of the ApoB100 (Xba Ⅰ ), ApoE (Hha Ⅰ ) and CYP7A1 (Bsa Ⅰ ) gene polymorphisms, with the development of cholesterol gallstone disease (GD) in a Mexican population. METHODS:...AIM: To determine the possible association of the ApoB100 (Xba Ⅰ ), ApoE (Hha Ⅰ ) and CYP7A1 (Bsa Ⅰ ) gene polymorphisms, with the development of cholesterol gallstone disease (GD) in a Mexican population. METHODS: The polymorphisms were analyzed by polymerase chain reaction followed by restriction fragment length polymorphism, in two groups matched by ethnicity, age and sex: patients with GD (n = 101) and stone-free control subjects (n = 101). RESULTS: Allelic frequencies in patients and controls were: 34.16% vs 41.58% (P = 0.124) for X+of ApoB-100; 4.46% vs 5.94% (P = 0.501) for E2, 85.64% vs 78.22% (P = 0.052) for E3, 9.90% vs 15.84% (P = 0.075) for E4 of ApoE; and 25.74% vs 27.72% (P = 0.653) for C of CYP7A1. Differences in genotypic frequencies between the studied groups were not significant (P < 0.05). CONCLUSION: These results demonstrated that no association exists between the studied polymorphisms and cholelithiasis in this high prevalent population.展开更多
Bile acids(BAs) are amphipathic molecules important for metabolism of cholesterol,absorption of lipids and lipid soluble vitamins,bile flow,and regulation of gut microbiome.There are over 30 different BA species known...Bile acids(BAs) are amphipathic molecules important for metabolism of cholesterol,absorption of lipids and lipid soluble vitamins,bile flow,and regulation of gut microbiome.There are over 30 different BA species known to exist in humans and mice,which are endogenous modulators of at least 6 different membrane or nuclear receptors.This diversity of ligands and receptors play important roles in health and disease;however,the full functions of each individual BA in vivo remain unclear.We generated a mouse model lacking the initiating enzymes,CYP7 A1 and CYP27 A1,in the two main pathways of BA synthesis.Because females are more susceptible to BA related diseases,such as intrahepatic cholestasis of pregnancy,we expanded this model into female mice.The null mice of Cyp7 a1 and Cyp27 a1 were crossbred to create double knockout(DKO) mice.BA concentrations in female DKO mice had reductions in serum(63%),liver(83%),gallbladder(94%),and small intestine(85%),as compared to WT mice.Despite low BA levels,DKO mice had a similar expression pattern to that of WT mice for genes involved in BA regulation,synthesis,conjugation,and transport.Additionally,through treatment with a synthetic FXR agonist,GW4064,female DKO mice responded to FXR activation similarly to WT mice.展开更多
文摘Background Genetic factors account for approximately 50% of the individual variation in plasma low-density lipoprotein cholesterol (LDL-C) concentrations in the general population. Several candidate genes have been proposed but their relative contributions to the variance in LDL-C are not known, except for apolipoprotein E (apoE). We report here an investigation of the relationship between LDL-C and cholesterol 7α-hydroxylase (CYP7), as well as apoE and low-density lipoprotein receptor (LDLR), three pivotal genes in LDL metabolism. Methods Our study population included more than 200 nuclear families with increased coronary heart disease (CHD) risk from the National Heart, Lung, and Blood Institute (NHLBI) Family Heart Study. Variance-component linkage methods, a measured genotype approach, and a variance-component linkage analysis conditional on a measured genotype association were used. Results The results showed significant linkage between a genetic determinant of plasma LDL-C concentrations and a polymorphism near CYP7 with its allelic variation accounting for 27% of the total LDL-C variation. There is significant association between plasma LDL-C concentrations and apoE genotypes. Conditional on the apoE association, the total LDL-C variation accounted by allelic variation of a polymorphism near CYP7 was increased significantly.Conclusion Our results suggest the apoE and CYP7 may be two important genes accounting for the genetic variation of plasma LDL-C concentrations in a population with cardiovascular diseases.
基金supported by the National Key Research and Development Program of China(grant No.SQ2018YFC100236)the National Natural Science Foundation of China(grant Nos.91857115,81522007,81470554,31401011,and 81700010)+1 种基金the Fundamental Research Funds for the Central Universities:Clinical Medicine Plus X-Young Scholars Project of Peking University(grant No.PKU2018LCXQ013,China)Beijing Nova Program(grant No.Z161100004916056,China)
文摘Since metabolic process differs between humans and mice, studies were performed in hamsters, which are generally considered to be a more appropriate animal model for studies of obesityrelated metabolic disorders. The modulation of gut microbiota, bile acids and the farnesoid X receptor(FXR) axis is correlated with obesity-induced insulin resistance and hepatic steatosis in mice. However,the interactions among the gut microbiota, bile acids and FXR in metabolic disorders remained largely unexplored in hamsters. In the current study, hamsters fed a 60% high-fat diet(HFD) were administeredvehicle or an antibiotic cocktail by gavage twice a week for four weeks. Antibiotic treatment alleviated HFD-induced glucose intolerance, hepatic steatosis and inflammation accompanied with decreased hepatic lipogenesis and elevated thermogenesis in subcutaneous white adipose tissue(sWAT). In the livers of antibiotic-treated hamsters, cytochrome P450 family 7 subfamily B member 1(CYP7 B1) in the alternative bile acid synthesis pathway was upregulated, contributing to a more hydrophilic bile acid profile with increased tauro-β-muricholic acid(TβMCA). The intestinal FXR signaling was suppressed but remained unchanged in the liver. This study is of potential translational significance in determining the role of gut microbiota-mediated bile acid metabolism in modulating diet-induced glucose intolerance and hepatic steatosis in the hamster.
基金Supported by PROFAPI-UAS and CECYT from Sinaloa, México
文摘AIM: To determine the possible association of the ApoB100 (Xba Ⅰ ), ApoE (Hha Ⅰ ) and CYP7A1 (Bsa Ⅰ ) gene polymorphisms, with the development of cholesterol gallstone disease (GD) in a Mexican population. METHODS: The polymorphisms were analyzed by polymerase chain reaction followed by restriction fragment length polymorphism, in two groups matched by ethnicity, age and sex: patients with GD (n = 101) and stone-free control subjects (n = 101). RESULTS: Allelic frequencies in patients and controls were: 34.16% vs 41.58% (P = 0.124) for X+of ApoB-100; 4.46% vs 5.94% (P = 0.501) for E2, 85.64% vs 78.22% (P = 0.052) for E3, 9.90% vs 15.84% (P = 0.075) for E4 of ApoE; and 25.74% vs 27.72% (P = 0.653) for C of CYP7A1. Differences in genotypic frequencies between the studied groups were not significant (P < 0.05). CONCLUSION: These results demonstrated that no association exists between the studied polymorphisms and cholelithiasis in this high prevalent population.
基金supported by the National Institutes of Health(NIHR01GM104037,NIH-R21ES029258,NIH-T32ES007148,VA-BX002741,NIH-F31DK122725,RCLR graduate student award fund,USA)。
文摘Bile acids(BAs) are amphipathic molecules important for metabolism of cholesterol,absorption of lipids and lipid soluble vitamins,bile flow,and regulation of gut microbiome.There are over 30 different BA species known to exist in humans and mice,which are endogenous modulators of at least 6 different membrane or nuclear receptors.This diversity of ligands and receptors play important roles in health and disease;however,the full functions of each individual BA in vivo remain unclear.We generated a mouse model lacking the initiating enzymes,CYP7 A1 and CYP27 A1,in the two main pathways of BA synthesis.Because females are more susceptible to BA related diseases,such as intrahepatic cholestasis of pregnancy,we expanded this model into female mice.The null mice of Cyp7 a1 and Cyp27 a1 were crossbred to create double knockout(DKO) mice.BA concentrations in female DKO mice had reductions in serum(63%),liver(83%),gallbladder(94%),and small intestine(85%),as compared to WT mice.Despite low BA levels,DKO mice had a similar expression pattern to that of WT mice for genes involved in BA regulation,synthesis,conjugation,and transport.Additionally,through treatment with a synthetic FXR agonist,GW4064,female DKO mice responded to FXR activation similarly to WT mice.
