Selective glutathione depletion of mitochondria by ethanol sensitizes hepatocytes to tumor necrosis factor
- 1 December 1998
- journal article
- Published by Elsevier BV in Gastroenterology
- Vol. 115 (6), 1541-1551
- https://doi.org/10.1016/s0016-5085(98)70034-4
Abstract
Background & Aims: Tumor necrosis factor (TNF)-α 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-α. Methods: Cultured hepatocytes from ethanol-fed (ethanol hepatocytes) or pair-fed (control hepatocytes) rats were exposed to TNF-α, 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-α. The susceptibility to TNF-α, manifested as necrosis rather than apoptosis, was accompanied by a progressive increase in hydrogen peroxide that correlated inversely with cell survival. Nuclear factor κB activation by TNF-α 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-α 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-α. Conclusions: These results indicate that mGSH controls the fate of hepatocytes in response to TNF-α. Its depletion caused by alcohol consumption amplifies the power of TNF-α to generate reactive oxygen species, compromising mitochondrial and cellular functions that culminate in cell death. GASTROENTEROLOGY 1998;115:1541-1551Keywords
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