title: Nitric oxide mimics transcriptional and post-translational regulation during α-tocopherol cytoprotection against glycochenodeoxycholate-induced cell death in hepatocytes.
abstract: OBJECTIVE
  Reactive oxygen species (ROS) and nitric oxide (NO) exert a relevant role during bile acid-induced hepatotoxicity. Whether α-Tocopherol regulates oxidative and nitrosative stress, bile acid transporter expression and their NO-dependent post-translational modifications, and cell death were assessed in vitro and in vivo.
  
  
  METHODS
  α-Tocopherol and/or NO donors (DETA-NONOate or CSNO, and V-PYRRO/NO) were administered to glycochenodeoxycholic acid (GCDCA)-treated cultured human hepatocytes or to bile duct obstructed rats. Cell injury, superoxide anion (O⁻₂) production, as well as inducible nitric oxide synthase (NOS-2), cytochrome P4507A1 (CYP7A1), heme oxygenase-1, (HO-1) and bile acid transporter expression were determined. Cysteine S-nitrosylation and tyrosine nitration of Na(+)-taurocholate co-transporting polypeptide (NTCP), as well as taurocholic acid (TC) uptake were also evaluated.
  
  
  RESULTS
  GCDCA-induced cell death was associated with increased (O⁻₂) production, NTCP and HO-1 expression, and with a reduction of CYP7A1 and NOS-2 expression. α-Tocopherol reduced cell death, (O⁻₂) production, CYP7A1, NTCP, and HO-1 expression, as well as increased NOS-2 expression and NO production in GCDCA-treated hepatocytes. α-Tocopherol and NO donors increased NTCP cysteine S-nitrosylation and tyrosine nitration, and reduced TC uptake in hepatocytes. α-Tocopherol and V-PYRRO/NO reduced liver injury and NTCP expression in obstructed rats.
  
  
  CONCLUSIONS
  The regulation of CYP7A1, NTCP, and HO-1 expression may be relevant for the cytoprotective properties of α-Tocopherol and NO against mitochondrial dysfunction, oxidative stress and cell death in GCDCA-treated hepatocytes. The regulation of NO-dependent post-translational modifications of NTCP by α-Tocopherol and NO donors reduces the uptake of toxic bile acids by hepatocytes.
authors.affiliation: Instituto Maimónides para la Investigación Biomédica de Córdoba, Reina Sofia University Hospital, Córdoba, Spain.
authors.forename: Raúl
authors.initials: R
authors.lastname: González
authors.forename: Adolfo
authors.initials: A
authors.lastname: Cruz
authors.forename: Gustavo
authors.initials: G
authors.lastname: Ferrín
authors.forename: Pedro
authors.initials: P
authors.lastname: López-Cillero
authors.forename: Rubén
authors.initials: R
authors.lastname: Fernández-Rodríguez
authors.forename: Javier
authors.initials: J
authors.lastname: Briceño
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Gómez
authors.forename: Sebastián
authors.initials: S
authors.lastname: Rufián
authors.forename: Manuel De la
authors.initials: Mde L
authors.lastname: Mata
authors.forename: Antonio
authors.initials: A
authors.lastname: Martínez-Ruiz
authors.forename: Jose J G
authors.initials: JJ
authors.lastname: Marin
authors.forename: Jordi
authors.initials: J
authors.lastname: Muntané
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D002779:Cholestasis / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D002790:Cholesterol 7-alpha-Hydroxylase / Q000378:metabolism; D019610:Cytoprotection / Q000187:drug effects; D004195:Disease Models, Animal; D005260:Female; D005999:Glycochenodeoxycholic Acid / Q000633:toxicity; D051547:Heme Oxygenase-1 / Q000378:metabolism; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D029363:Organic Anion Transporters, Sodium-Dependent / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D051381:Rats; D027981:Symporters / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D024502:alpha-Tocopherol / Q000494:pharmacology*
chemical_list: D020030:Nitric Oxide Donors; D029363:Organic Anion Transporters, Sodium-Dependent; D027981:Symporters; C071908:sodium-bile acid cotransporter; D009569:Nitric Oxide; D005999:Glycochenodeoxycholic Acid; D051547:Heme Oxygenase-1; C553219:CYP7A1 protein, human; C532838:CYP7A1 protein, rat; D002790:Cholesterol 7-alpha-Hydroxylase; D024502:alpha-Tocopherol