Depletion of Hepatic Glutathione Prevents Death Receptor-Dependent Apoptotic and Necrotic Liver Injury in Mice

摘要

The activation of the death receptors, tumor necrosis factor-receptor-1 (TNF-R1) or CD95, is a hallmark of inflammatory or viral liver disease. In different murine in vivo models, we found that livers depleted of -glutamyl-cysteinyl-glycine (GSH) by endogenous enzymatic conjugation after phorone treatment were resistant against death receptor-elicited injury as assessed by transaminase release and histopathology. In apoptotic models initiated by engagement of CD95, or by injection of TNF or lipopolysaccharide into galactosamine-sensitized mice, hepatic caspase-3-like proteases were not activated in the GSH-depleted state. Under GSH depletion, also caspase-independent, TNF-R1-mediated injury (high-dose actinomycin D or -amanitin), as well as necrotic hepatotoxicity (high-dose lipopolysaccharide) were entirely blocked. In the T-cell-dependent model of concanavalin A-induced hepatotoxicity, GSH depletion resulted in a suppression of interferon- release, delay of systemic TNF release, hepatic nuclear factor-B activation, and an abrogation of sinusoidal endothelial cell detachment as assessed by electron microscopy. When GSH depletion was initiated 3 hours after concanavalin A injection, ie, after the peak of early pro-inflammatory cytokines, livers were still protected. We conclude that sufficient hepatic GSH levels are a prerequisite for the execution of death receptor-mediated hepatocyte demise.