title: Selective glutathione depletion of mitochondria by ethanol sensitizes hepatocytes to tumor necrosis factor.
abstract: OBJECTIVE
  Tumor necrosis factor (TNF)-alpha induces cell injury by generating oxidative stress from mitochondria. The purpose of this study was to determine the effect of ethanol on the sensitization of hepatocytes to TNF-alpha.
  
  
  METHODS
  Cultured hepatocytes from ethanol-fed (ethanol hepatocytes) or pair-fed (control hepatocytes) rats were exposed to TNF-alpha, and the extent of oxidative stress, gene expression, and viability were evaluated.
  
  
  RESULTS
  Ethanol hepatocytes, which develop a selective deficiency of mitochondrial glutathione (mGSH), showed marked susceptibility to TNF-alpha. The susceptibility to TNF-alpha, manifested as necrosis rather than apoptosis, was accompanied by a progressive increase in hydrogen peroxide that correlated inversely with cell survival. Nuclear factor kappaB activation by TNF-alpha was significantly greater in ethanol hepatocytes than in control hepatocytes, an effect paralleled by the expression of cytokine-induced neutrophil chemoattractant. Similar sensitization of normal hepatocytes to TNF-alpha was obtained by depleting the mitochondrial pool of GSH with 3-hydroxyl-4-pentenoate. Restoration of mGSH by S-adenosyl-L-methionine or by GSH-ethyl ester prevented the increased susceptibility of ethanol hepatocytes to TNF-alpha.
  
  
  CONCLUSIONS
  These results indicate that mGSH controls the fate of hepatocytes in response to TNF-alpha. Its depletion caused by alcohol consumption amplifies the power of TNF-alpha to generate reactive oxygen species, compromising mitochondrial and cellular functions that culminate in cell death.
authors.affiliation: Liver Unit, Department of Medicine, Hospital Clinic i Provincial and Instituto Investigaciones Biomédicas, Consejo Superior Investigaciones Cientificas, Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Colell
authors.forename: C
authors.initials: C
authors.lastname: García-Ruiz
authors.forename: M
authors.initials: M
authors.lastname: Miranda
authors.forename: E
authors.initials: E
authors.lastname: Ardite
authors.forename: M
authors.initials: M
authors.lastname: Marí
authors.forename: A
authors.initials: A
authors.lastname: Morales
authors.forename: F
authors.initials: F
authors.lastname: Corrales
authors.forename: N
authors.initials: N
authors.lastname: Kaplowitz
authors.forename: J C
authors.initials: JC
authors.lastname: Fernández-Checa
mesh_terms: D000818:Animals; D000431:Ethanol / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism*; D008099:Liver / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008928:Mitochondria / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012436:S-Adenosylmethionine / Q000494:pharmacology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*
chemical_list: D014409:Tumor Necrosis Factor-alpha; D000431:Ethanol; D012436:S-Adenosylmethionine; D005978:Glutathione