Inhibition of IRAK4 kinase activity improves ethanol-induced liver injury in mice

J Hepatol. 2020 Dec;73(6):1470-1481. doi: 10.1016/j.jhep.2020.07.016. Epub 2020 Jul 16.

Abstract

Backgrounds & aims: Alcohol-related liver disease (ALD) is a major cause of chronic liver disease worldwide with limited therapeutic options. Interleukin-1 receptor associated kinase 4 (IRAK4), the master kinase of Toll-like receptor (TLR)/IL-1R-mediated signalling activation, is considered a novel therapeutic target in inflammatory diseases, but has not been investigated in the context of ALD.

Methods: IRAK4 phosphorylation and IRAK1 protein were analysed in liver from alcohol-related hepatitis patients and healthy controls. IRAK4 kinase activity-inactive knock-in (Irak4 KI) mice and bone marrow chimeric mice were exposed to chronic ethanol-induced liver injury. IL-1β-induced IRAK4-mediated signalling and acute phase response were investigated in cultured hepatocytes. IRAK1/4 inhibitor was used to test the therapeutic potential for ethanol-induced liver injury in mice.

Results: Increased IRAK4 phosphorylation and reduced IRAK1 protein were found in livers of patients with alcoholic hepatitis. In the chronic ethanol-induced liver injury mouse model, hepatic inflammation and hepatocellular damage were attenuated in Irak4 KI mice. IRAK4 kinase activity promotes expression of acute phase proteins in response to ethanol exposure, including C-reactive protein and serum amyloid A1 (SAA1). SAA1 and IL-1β synergistically exacerbate ethanol-induced cell death ex vivo. Pharmacological blockage of IRAK4 kinase abrogated ethanol-induced liver injury, inflammation, steatosis, as well as acute phase gene expression and protein production in mice.

Conclusions: Our data elucidate the critical role of IRAK4 kinase activity in the pathogenesis of ethanol-induced liver injury in mice and provide preclinical validation for use of an IRAK1/4 inhibitor as a new potential therapeutic strategy for the treatment of ALD.

Lay summary: Herein, we have identified the role of IRAK4 kinase activity in the development of alcohol-induced liver injury in mice. Hepatocyte-specific IRAK4 is associated with an acute phase response and release of proinflammatory cytokines/chemokines, which synergistically exacerbate alcohol-induced hepatocyte cell death ex vivo. Pharmacological inhibition of IRAK4 kinase activity effectively attenuates alcohol-induced liver injury in mice and could have therapeutic implications.

Keywords: Acute phase protein; Alcoholic liver disease; Hepatocyte; IRAK4; Inflammation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Acute-Phase Proteins / metabolism
  • Animals
  • Cells, Cultured
  • Chemical and Drug Induced Liver Injury* / drug therapy
  • Chemical and Drug Induced Liver Injury* / metabolism
  • Humans
  • Immune Checkpoint Inhibitors / pharmacology*
  • Interleukin-1 Receptor-Associated Kinases / antagonists & inhibitors*
  • Interleukin-1 Receptor-Associated Kinases / metabolism*
  • Interleukin-1beta / metabolism
  • Liver Diseases, Alcoholic / metabolism*
  • Liver Diseases, Alcoholic / pathology
  • Mice
  • Mice, Inbred C57BL
  • Peptide Fragments / metabolism
  • Phosphorylation
  • Receptors, Interleukin-1 / metabolism
  • Signal Transduction / drug effects
  • Toll-Like Receptors / metabolism
  • Treatment Outcome

Substances

  • Acute-Phase Proteins
  • Immune Checkpoint Inhibitors
  • Interleukin-1beta
  • Peptide Fragments
  • Receptors, Interleukin-1
  • Toll-Like Receptors
  • interleukin-1beta (163-171)
  • IRAK4 protein, human
  • Interleukin-1 Receptor-Associated Kinases
  • Irak1 protein, mouse
  • Irak4 protein, mouse