title: Up-Regulation of CYP2C19 Expression by BuChang NaoXinTong via PXR Activation in HepG2 Cells.
abstract: BACKGROUND
  Cytochrome P450 2C19 (CYP2C19) is an important drug-metabolizing enzyme (DME), which is responsible for the biotransformation of several kinds of drugs such as proton pump inhibitors, platelet aggregation inhibitors and antidepressants. Previous studies showed that Buchang NaoXinTong capsules (NXT) increased the CYP2C19 metabolic activity in vitro and enhanced the antiplatelet effect of clopidogrel in vivo. However, the underlying molecular mechanism remained unclear. In the present study, we examined whether Pregnane X receptor (PXR) plays a role in NXT-mediated regulation of CYP2C19 expression.
  
  
  METHODS
  We applied luciferase assays, real-time quantitative PCR (qPCR), Western blotting and cell-based analysis of metabolic activity experiments to investigate the NXT regulatory effects on the CYP2C19 promoter activity, the mRNA/ protein expression and the metabolic activity.
  
  
  RESULTS
  Our results demonstrated that NXT significantly increased the CYP2C19 promoter activity when co-transfected with PXR in HepG2 cells. Mutations in PXR responsive element abolished the NXT inductive effects on the CYP2C19 promoter transcription. Additionally, NXT incubation (150 and 250μg/mL) also markedly up-regulated endogenous CYP2C19 mRNA and protein levels in PXR-transfected HepG2 cells. Correspondingly, NXT leaded to a significant enhancement of the CYP2C19 catalytic activity in PXR-transfected HepG2 cells.
  
  
  CONCLUSIONS
  In summary, this is the first study to suggest that NXT could induce CYP2C19 expression via PXR activation.
authors.affiliation: Department of Pharmacy, Provincial Clinical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, Fujan, P. R. China.
authors.forename: Hong
authors.initials: H
authors.lastname: Sun
authors.affiliation: Department of Clinical Pharmacology, Xiangya Hospital and Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha, Hunan, P. R. China.
authors.forename: Xiao-Ya
authors.initials: XY
authors.lastname: Lou
authors.affiliation: Hypertension Laboratory, Provincial Clinical College of Fujian Medical University, Fujian Provincial Cardiovascular Disease Institute, Fujian Provincial Hospital, Fuzhou, Fujian, P. R. China.
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Wu
authors.affiliation: Hypertension Laboratory, Provincial Clinical College of Fujian Medical University, Fujian Provincial Cardiovascular Disease Institute, Fujian Provincial Hospital, Fuzhou, Fujian, P. R. China.
authors.forename: Huan
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, Hunan, P. R. China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Qu
authors.affiliation: Department of Pharmacy, the Second Xiangya Hospital, Central South University; Institute of Clinical Pharmacy, Central South University, Changsha, Hunan, P. R. China.
authors.forename: Shen-Lan
authors.initials: SL
authors.lastname: Tan
authors.affiliation: Department of Pharmacy, Provincial Clinical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, Fujan, P. R. China.
authors.forename: Jun-Shan
authors.initials: JS
authors.lastname: Ruan
authors.affiliation: Department of Pharmacy, the Second Xiangya Hospital, Central South University; Institute of Clinical Pharmacy, Central South University, Changsha, Hunan, P. R. China.
authors.forename: Jian
authors.initials: J
authors.lastname: Qu
authors.affiliation: Hypertension Laboratory, Provincial Clinical College of Fujian Medical University, Fujian Provincial Cardiovascular Disease Institute, Fujian Provincial Hospital, Fuzhou, Fujian, P. R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
mesh_terms: D065731:Cytochrome P-450 CYP2C19 / Q000235:genetics / Q000378:metabolism*; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D056945:Hep G2 Cells; D006801:Humans; D000077297:Pregnane X Receptor; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D011987:Receptors, Steroid / Q000378:metabolism*; D014158:Transcription, Genetic; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D004365:Drugs, Chinese Herbal; D000077297:Pregnane X Receptor; D012333:RNA, Messenger; D011987:Receptors, Steroid; C533635:buchang naoxintong; D065731:Cytochrome P-450 CYP2C19