Background: Acute hepatic failure secondary to paracetamol poisoning is associated with high mortality. C-jun (NH2) terminal kinase (JNK) is a member of the mitogen activated protein kinase family and is a key intracellular signaling molecule involved in the control of cell fate.
Methods: Using a previously developed mouse model of paracetamol poisoning, we examined in detail the role of JNK in paracetamol induced acute liver failure.
Results: We demonstrate that paracetamol induced hepatic JNK activation in both human and murine paracetamol hepatotoxicity, and in our murine model preceded the onset of hepatocyte death. JNK inhibition in vivo (using two JNK inhibitors with different mechanisms of action) markedly reduced mortality in murine paracetamol hepatotoxicity, with a significant reduction in hepatic necrosis and apoptosis. In addition, delayed administration of JNK inhibitor was more effective than N-acetylcysteine following paracetamol poisoning in mice. JNK inhibition was not protective in acute carbon tetrachloride or anti-Fas antibody mediated hepatic injury, suggesting specificity for the role of JNK in paracetamol hepatotoxicity. Furthermore, disruption of the JNK1 or JNK2 genes did not protect against paracetamol-induced hepatic damage. Pharmacological JNK inhibition had no effect on paracetamol metabolism, but markedly inhibited hepatic TNF-a production following paracetamol poisoning.
Conclusions: These data demonstrate a central role for JNK in the pathogenesis of paracetamol induced liver failure, thereby identifying JNK as an important therapeutic target in the treatment of paracetamol hepatotoxicity.