Abstract
Background
The reversible glutathionylation modification (PSSG) of Fas augments apoptosis, which can be reversed by the cytosolic deglutathionylation enzyme glutaredoxin-1 (Grx1), but its roles in alcoholic liver injury remain unknown. Therefore, the objective of this study was to investigate the impact of genetic ablation of Grx1 on Fas-SSG in regulating ethanol-induced injury.
Methods
The role of Grx1 in alcoholic liver injury was investigated in Grx1 knockout mice. Alcoholic liver injury was achieved by feeding mice with a liquid diet containing 5% ethanol for 2 weeks.
Results
We demonstrated that ethanol-fed mice had increased Grx1 activity and oxidative damage in the liver. On the other hand, Grx1-deficient mice had more serious liver damage when exposed to ethanol compared to that of wild-type mice, accompanied by increased alanine aminotransferase and aspartate aminotransferase levels, Fas-SSG, cleaved caspase-3 and hepatocyte apoptosis. Grx1 ablation resulted in the suppression of ethanol-induced nuclear factor-κB (NF-κB) signaling, its downstream signal, and Akt signaling cascades, which are required for protection against Fas-mediated apoptosis. Accordingly, blocking NK-κB prevented Fas-induced apoptosis in WT mice but not Grx1-/- mice. Furthermore, the number of Kupffer cells and related proinflammatory cytokines, including Akt, were lower in Grx1-/- livers than those of the controls.
Conclusions
Grx1 is essential for adaptation to alcohol exposure-induced oxidative injury by modulating Fas-SSG and Fas-induced apoptosis.
Aberrant Hepatic Methionine Metabolism and Gene Methylation in the Pathogenesis and Treatment of Alcoholic Steatohepatitis