The pseudokinase MLKL mediates programmed hepatocellular necrosis independently of RIPK3 during hepatitis

J Clin Invest. 2016 Nov 1;126(11):4346-4360. doi: 10.1172/JCI87545. Epub 2016 Oct 17.

Abstract

Although necrosis and necroinflammation are central features of many liver diseases, the role of programmed necrosis in the context of inflammation-dependent hepatocellular death remains to be fully determined. Here, we have demonstrated that the pseudokinase mixed lineage kinase domain-like protein (MLKL), which plays a key role in the execution of receptor-interacting protein (RIP) kinase-dependent necroptosis, is upregulated and activated in human autoimmune hepatitis and in a murine model of inflammation-dependent hepatitis. Using genetic and pharmacologic approaches, we determined that hepatocellular necrosis in experimental hepatitis is driven by an MLKL-dependent pathway that occurs independently of RIPK3. Moreover, we have provided evidence that the cytotoxic activity of the proinflammatory cytokine IFN-γ in hepatic inflammation is strongly connected to induction of MLKL expression via activation of the transcription factor STAT1. In summary, our results reveal a pathway for MLKL-dependent programmed necrosis that is executed in the absence of RIPK3 and potentially drives the pathogenesis of severe liver diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Hepatitis, Autoimmune / enzymology*
  • Hepatitis, Autoimmune / genetics
  • Hepatitis, Autoimmune / pathology
  • Hepatocytes / enzymology*
  • Hepatocytes / pathology
  • Humans
  • Interferon-gamma / genetics
  • Interferon-gamma / metabolism
  • Mice
  • Mice, Knockout
  • Necrosis
  • Protein Kinases / genetics
  • Protein Kinases / metabolism*
  • Receptor-Interacting Protein Serine-Threonine Kinases / genetics
  • Receptor-Interacting Protein Serine-Threonine Kinases / metabolism*
  • STAT1 Transcription Factor / genetics
  • STAT1 Transcription Factor / metabolism

Substances

  • IFNG protein, human
  • IFNG protein, mouse
  • STAT1 Transcription Factor
  • STAT1 protein, human
  • Stat1 protein, mouse
  • Interferon-gamma
  • MLKL protein, human
  • MLKL protein, mouse
  • Protein Kinases
  • RIPK3 protein, human
  • Receptor-Interacting Protein Serine-Threonine Kinases
  • Ripk3 protein, mouse