Abstract
Acetaminophen (APAP) is one of the most commonly used drugs worldwide, and APAP-induced liver injury is the most frequent cause of acute liver failure in developed countries. However, the mechanisms of APAP-induced hepatotoxicity are not well understood, and treatment options for the disorder are very limited. Here, we show that TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) is a major mediator of APAP-induced liver injury in mice, and its blockade markedly ameliorates the liver failure. In APAP-treated mice, TRAIL was expressed in the liver, spleen, and peripheral blood primarily by CD11b+Gr1+ neutrophils. The concentration of soluble TRAIL in the blood, and the frequencies of TRAIL+ leukocytes in the spleen and liver positively correlated with the severity of liver injury. APAP sensitized hepatocytes to TRAIL-induced apoptosis by upregulating the expression of the TRAIL receptor DR5 (death receptor 5), presumably through its transcription factor CHOP (C/EBP homologous protein). Importantly, blocking TRAIL with a soluble DR5-Fc fusion protein (sDR5-Fc) significantly attenuated APAP-induced liver injury, the hepatic infiltration of leukocytes, the levels of inflammatory cytokines, and the mortality of mice. When administered alongside N-acetylcysteine, sDR5-Fc further protected against APAP-induced acute liver injury. Thus, the TRAIL-DR5 signaling pathway plays a key role in APAP-induced liver inflammation and failure, and its blockade represents an effective new strategy to treat the liver disease.