title: Reduced glutathione depletion causes necrosis and sensitization to tumor necrosis factor-alpha-induced apoptosis in cultured mouse hepatocytes.
abstract: The effect of reduced glutathione (GSH) depletion by acetaminophen (APAP), diethylmaleate (DEM), or phorone on the mode of cell death and susceptibility to tumor necrosis factor (TNF)-induced cell death was studied in cultured mouse hepatocytes. Dose-dependent necrosis was the exclusive mode of cell death with APAP alone, but the addition of TNF-alpha induced a switch to about half apoptosis without changing total loss of viability. This effect was seen at 1 and 5 mmol/L but was inhibited at 10 and 20 mmol/L APAP. The switch to apoptosis was associated with increased caspase activities, release of cytochrome c, and DNA laddering and was inhibited by caspase inhibitors. DEM and phorone also induced dose-dependent necrosis. Treatment with TNF-alpha under these conditions lead to incremental cell death in the form of apoptosis at 0.25 and 0.5 mmol/L DEM and 0.1 and 0.2 mmol/L phorone. At 1.0 and 2.0 mmol/L DEM and 0.5 mmol/L phorone, 90% to 100% necrosis was observed with resistance to TNF-alpha effects. The apoptosis with TNF-alpha plus DEM was confirmed by DNA laddering and inhibition by caspase inhibitors. However, in the presence of caspase inhibitors, the increment in cell death induced by TNF-alpha persisted as an increase in necrosis. A combination of antioxidants, vitamin E, and butylated hydroxytoluene (BHT) markedly inhibited necrosis induced by APAP or DEM alone, but the sensitization to TNF-alpha-induced apoptosis was unaffected. GSH monoethylester (GSH-EE) protected against necrosis and apoptosis. In conclusion, depletion of GSH by APAP, DEM, or phorone causes oxidative stress-induced necrosis and sensitizes to an oxidative stress independent TNF-alpha-induced apoptosis.
authors.affiliation: USC Research Center for Liver Diseases, USC-UCLA Research Center for Alcoholic and Pancreatic Disease, Keck School of Medicine, University of Southern California, 2011 Zonal Avenue, Los Angeles, CA 90033, USA.
authors.forename: Hidenari
authors.initials: H
authors.lastname: Nagai
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Matsumaru
authors.forename: Guoping
authors.initials: G
authors.lastname: Feng
authors.forename: Neil
authors.initials: N
authors.lastname: Kaplowitz
mesh_terms: D000082:Acetaminophen / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D002084:Butylated Hydroxytoluene / Q000494:pharmacology; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D003574:Cytochrome c Group / Q000378:metabolism; D053938:DNA Fragmentation; D005978:Glutathione / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D022781:Hepatocytes / Q000166:cytology*; D007659:Ketones / Q000494:pharmacology; D008298:Maleates / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000494:pharmacology; D009336:Necrosis; D018384:Oxidative Stress; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014810:Vitamin E / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D061945:Caspase Inhibitors; D003574:Cytochrome c Group; D007659:Ketones; D008298:Maleates; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D014810:Vitamin E; D002084:Butylated Hydroxytoluene; D000082:Acetaminophen; C018637:phorone; D020169:Caspases; C014476:diethyl maleate; D005978:Glutathione