title: Cholesterol-lowing effect of taurine in HepG2 cell.
abstract: BACKGROUND
  A number of studies indicate that taurine promotes cholesterol conversion to bile acids by upregulating CYP7A1 gene expression. Few in vitro studies are concerned the concentration change of cholesterol and its product of bile acids, and the molecular mechanism of CYP7A1 induction by taurine.
  
  
  METHODS
  The levels of intracellular total cholesterol (TC), free cholesterol (FC), cholesterol ester (EC), total bile acids (TBA) and medium TBA were determined after HepG2 cells were cultured for 24/48 h in DMEM supplemented with taurine at the final concentrations of 1/10/20 mM respectively. The protein expressions of CYP7A1, MEK1/2, c-Jun, p-c-Jun and HNF-4α were detected.
  
  
  RESULTS
  Taurine significantly reduced cellular TC and FC in dose -and time-dependent ways, and obviously increased intracellular/medium TBA and CYP7A1 expressions. There was no change in c-Jun expression, but the protein expressions of MEK1/2 and p-c-Jun were increased at 24 h and inhibited at 48 h by 20 mM taurine while HNF4α was induced after both of the 24 h and 48 h treatment.
  
  
  CONCLUSIONS
  Taurine could enhance CYP7A1 expression by inducing HNF4α and inhibiting MEK1/2 and p-c-Jun expressions to promote intracellular cholesterol metabolism.
authors.affiliation: Food Science Department, College of Biochemical Engineering, Beijing Union University, Fatou west 18#, Chaoyang District, Beijing, 100023, People's Republic of China.|Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, 100191, People's Republic of China.
authors.forename: Junxia
authors.initials: J
authors.lastname: Guo
authors.affiliation: Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, 100191, People's Republic of China.
authors.forename: Ya
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, 100191, People's Republic of China.
authors.forename: Xuelian
authors.initials: X
authors.lastname: Cao
authors.affiliation: Food Science Department, College of Biochemical Engineering, Beijing Union University, Fatou west 18#, Chaoyang District, Beijing, 100023, People's Republic of China.|Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, 100191, People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Food Science Department, College of Biochemical Engineering, Beijing Union University, Fatou west 18#, Chaoyang District, Beijing, 100023, People's Republic of China. wlchenwen@buu.edu.cn.|Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, 100191, People's Republic of China. wlchenwen@buu.edu.cn.
authors.forename: Wen
authors.initials: W
authors.lastname: Chen
mesh_terms: D000924:Anticholesteremic Agents / Q000494:pharmacology*; D001647:Bile Acids and Salts / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism*; D002790:Cholesterol 7-alpha-Hydroxylase / Q000235:genetics / Q000378:metabolism; D065693:Cytochrome P-450 Enzyme Inducers / Q000494:pharmacology; D004353:Drug Evaluation, Preclinical; D004790:Enzyme Induction / Q000187:drug effects; D056945:Hep G2 Cells; D006801:Humans; D013654:Taurine / Q000494:pharmacology*
chemical_list: D000924:Anticholesteremic Agents; D001647:Bile Acids and Salts; D065693:Cytochrome P-450 Enzyme Inducers; D013654:Taurine; D002784:Cholesterol; C553219:CYP7A1 protein, human; D002790:Cholesterol 7-alpha-Hydroxylase
keywords: Bile acids; Cholesterol; HepG2 cell; Taurine