Critical role for mixed-lineage kinase 3 in acetaminophen-induced hepatotoxicity.
c-Jun NH(2)-terminal kinase (JNK) activation plays a major role in acetaminophen (APAP)-induced hepatotoxicity. However, the exact mechanism of APAP-induced JNK activation is incompletely understood. It has been established that apoptosis signal-regulating kinase 1 (ASK1) regulates the late phase of APAP-induced JNK activation, but the mitogen-activated protein kinase kinase kinase that mediates the initial phase of APAP-induced JNK activation has not been identified. Oxidative stress produced during APAP metabolism causes JNK activation, which promotes mitochondrial dysfunction and results in the amplification of oxidative stress. Therefore, inhibition of the initial phase of JNK activation may be key to protection against APAP-induced liver injury. The goal of this study was to determine whether mixed-lineage kinase 3 (MLK3) mediates the initial, ASK1-independent phase of APAP-induced JNK activation and thus promotes drug-induced hepatotoxicity. We found that MLK3 was activated by oxidative stress and was required for JNK activation in response to oxidative stress. Loss of MLK3 attenuated APAP-induced JNK activation and hepatocyte death in vitro, independent of receptor-interacting protein 1. Moreover, JNK and glycogen synthase kinase 3β activation was significantly attenuated, and Mcl-1 degradation was inhibited in APAP-treated MLK3-knockout mice. Furthermore, we showed that loss of MLK3 increased expression of glutamate cysteine ligase, accelerated hepatic GSH recovery, and decreased production of reactive oxygen species after APAP treatment. MLK3-deficient mice were significantly protected from APAP-induced liver injury, compared with wild-type mice. Together, these studies establish a novel role for MLK3 in APAP-induced JNK activation and hepatotoxicity, and they suggest MLK3 as a possible target in the treatment of APAP-induced liver injury.
Department of Pathology, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio 45237, USA.
Manju
M
Sharma
Vidya
V
Gadang
Anja
A
Jaeschke
D000082:Acetaminophen / Q000633:toxicity*; D000818:Animals; D045744:Cell Line, Tumor; D056486:Chemical and Drug Induced Liver Injury / Q000201:enzymology* / Q000209:etiology; D004789:Enzyme Activation; D020690:GTPase-Activating Proteins / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D048848:MAP Kinase Kinase Kinase 5 / Q000378:metabolism; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D000097767:Mitogen-Activated Protein Kinase Kinase Kinase 11
D000082:Acetaminophen; D020690:GTPase-Activating Proteins; D005978:Glutathione; D048031:JNK Mitogen-Activated Protein Kinases; D048848:MAP Kinase Kinase Kinase 5; D020930:MAP Kinase Kinase Kinases; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D000097767:Mitogen-Activated Protein Kinase Kinase Kinase 11; C579094:Mcl1 protein, mouse; C490620:Ralbp1 protein, mouse