title: AP-1 Inhibition by SR 11302 Protects Human Hepatoma HepG2 Cells from Bile Acid-Induced Cytotoxicity by Restoring the NOS-3 Expression.
abstract: The harmful effects of bile acid accumulation occurring during cholestatic liver diseases have been associated with oxidative stress increase and endothelial nitric oxide synthase (NOS-3) expression decrease in liver cells. We have previously reported that glycochenodeoxycholic acid (GCDCA) down-regulates gene expression by increasing SP1 binding to the NOS-3 promoter in an oxidative stress dependent manner. In the present study, we aimed to investigate the role of transcription factor (TF) AP-1 on the NOS-3 deregulation during GCDCA-induced cholestasis. The cytotoxic response to GCDCA was characterized by 1) the increased expression and activation of TFs cJun and c-Fos; 2) a higher binding capability of these at position -666 of the NOS-3 promoter; 3) a decrease of the transcriptional activity of the promoter and the expression and activity of NOS-3; and 4) the expression increase of cyclin D1. Specific inhibition of AP-1 by the retinoid SR 11302 counteracted the cytotoxic effects induced by GCDCA while promoting NOS-3 expression recovery and cyclin D1 reduction. NOS activity inhibition by L-NAME inhibited the protective effect of SR 11302. Inducible NOS isoform was no detected in this experimental model of cholestasis. Our data provide direct evidence for the involvement of AP-1 in the NOS-3 expression regulation during cholestasis and define a critical role for NOS-3 in regulating the expression of cyclin D1 during the cell damage induced by bile acids. AP-1 appears as a potential therapeutic target in cholestatic liver diseases given its role as a transcriptional repressor of NOS-3.
authors.affiliation: Maimonides Institute of Biomedical Research in Córdoba (IMIBIC), Reina Sofía University Hospital, University of Córdoba, Córdoba, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: González-Rubio
authors.affiliation: Maimonides Institute of Biomedical Research in Córdoba (IMIBIC), Reina Sofía University Hospital, University of Córdoba, Córdoba, Spain.
authors.forename: Clara I
authors.initials: CI
authors.lastname: Linares
authors.affiliation: Maimonides Institute of Biomedical Research in Córdoba (IMIBIC), Reina Sofía University Hospital, University of Córdoba, Córdoba, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Aguilar-Melero
authors.affiliation: Maimonides Institute of Biomedical Research in Córdoba (IMIBIC), Reina Sofía University Hospital, University of Córdoba, Córdoba, Spain.|Biomedical Research Centre Network, Digestive and Liver Diseases (CIBEREHD), Instituto de Salud Carlos III, Córdoba, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Rodríguez-Perálvarez
authors.affiliation: Maimonides Institute of Biomedical Research in Córdoba (IMIBIC), Reina Sofía University Hospital, University of Córdoba, Córdoba, Spain.|Biomedical Research Centre Network, Digestive and Liver Diseases (CIBEREHD), Instituto de Salud Carlos III, Córdoba, Spain.
authors.forename: José L
authors.initials: JL
authors.lastname: Montero-Álvarez
authors.affiliation: Maimonides Institute of Biomedical Research in Córdoba (IMIBIC), Reina Sofía University Hospital, University of Córdoba, Córdoba, Spain.|Biomedical Research Centre Network, Digestive and Liver Diseases (CIBEREHD), Instituto de Salud Carlos III, Córdoba, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: de la Mata
authors.affiliation: Maimonides Institute of Biomedical Research in Córdoba (IMIBIC), Reina Sofía University Hospital, University of Córdoba, Córdoba, Spain.|Biomedical Research Centre Network, Digestive and Liver Diseases (CIBEREHD), Instituto de Salud Carlos III, Córdoba, Spain.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Ferrín
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology; D019938:Cyclin D1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects*; D017930:Genes, Reporter; D005999:Glycochenodeoxycholic Acid / Q000633:toxicity*; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D052250:Nitric Oxide Synthase Type III / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D011401:Promoter Regions, Genetic; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D012176:Retinoids / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D018808:Transcription Factor AP-1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012176:Retinoids; C106195:SR 11302; D018808:Transcription Factor AP-1; D019938:Cyclin D1; D005999:Glycochenodeoxycholic Acid; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; D019331:NG-Nitroarginine Methyl Ester