Alcohol-induced IL-17A production in Paneth cells amplifies endoplasmic reticulum stress, apoptosis, and inflammasome-IL-18 activation in the proximal small intestine in mice

Mucosal Immunol. 2019 Jul;12(4):930-944. doi: 10.1038/s41385-019-0170-4. Epub 2019 May 19.

Abstract

Gut microbial translocation contributes to alcoholic hepatitis. Using a mouse model of alcoholic hepatitis, we investigated the effects of chronic alcohol plus binge and found increased abundance of Paneth cells and IL-17A in the proximal small intestine (PSI). Alcohol increased IL-17A production and pro-apoptotic signaling evidenced by Bax, Bim, caspase-3, and caspase-8 increases via endoplasmic reticulum (ER) stress indicated by C/EBP homologous protein (CHOP) upregulation; this was prevented by the ER stress inhibitor, 4-PBA, in isolated crypts in vitro and in vivo. Mechanistically, IL-17 augmented alcohol-induced ER stress in isolated crypts. In vivo IL-17A blocking antibody administration in alcohol-treated mice attenuated ER stress-mediated apoptosis and IL-18 induction and prevented alcohol-induced impairment of tight junctions in the PSI and LPS translocation to the liver. Acute-on-chronic alcohol resulted in inflammasome activation, caspase-1 cleavage, and IL-18 production in the PSI. In vivo treatment with antibiotics or 4-PBA prevented CHOP upregulation and inflammasome activation. Our data suggest that alcohol upregulates innate immune mechanisms by increasing Paneth cell numbers and IL-17A release contributing to apoptosis amplification, inflammasome activation, and gut leakiness in the PSI. Binge alcohol-induced Paneth cell expansion, ER stress, and inflammasome activation in the PSI are modulated by the gut microbiome.

Publication types

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

MeSH terms

  • Alcohol Drinking
  • Animals
  • Apoptosis* / drug effects
  • Biopsy
  • Caspases / metabolism
  • Cell Degranulation
  • Endoplasmic Reticulum Stress* / drug effects
  • Inflammasomes / metabolism*
  • Interleukin-17 / biosynthesis*
  • Interleukin-18 / metabolism*
  • Intestinal Mucosa / metabolism
  • Intestinal Mucosa / pathology
  • Intestine, Small / metabolism*
  • Mice
  • Paneth Cells / drug effects
  • Paneth Cells / metabolism*
  • Signal Transduction
  • Transcription Factor CHOP / metabolism

Substances

  • Ddit3 protein, mouse
  • Inflammasomes
  • Interleukin-17
  • Interleukin-18
  • Transcription Factor CHOP
  • Caspases