Intestinal restriction of Salmonella Typhimurium requires caspase-1 and caspase-11 epithelial intrinsic inflammasomes

PLoS Pathog. 2020 Apr 13;16(4):e1008498. doi: 10.1371/journal.ppat.1008498. eCollection 2020 Apr.

Abstract

We investigated the role of the inflammasome effector caspases-1 and -11 during Salmonella enterica serovar Typhimurium infection of murine intestinal epithelial cells (IECs). Salmonella burdens were significantly greater in the intestines of caspase-1/11 deficient (Casp1/11-/-), Casp1-/- and Casp11-/- mice, as compared to wildtype mice. To determine if this reflected IEC-intrinsic inflammasomes, enteroid monolayers were derived and infected with Salmonella. Casp11-/- and wildtype monolayers responded similarly, whereas Casp1-/- and Casp1/11-/- monolayers carried significantly increased intracellular burdens, concomitant with marked decreases in IEC shedding and death. Pretreatment with IFN-γ to mimic inflammation increased caspase-11 levels and IEC death, and reduced Salmonella burdens in Casp1-/- monolayers, while high intracellular burdens and limited cell shedding persisted in Casp1/11-/- monolayers. Thus caspase-1 regulates inflammasome responses in IECs at baseline, while proinflammatory activation of IECs reveals a compensatory role for caspase-11. These results demonstrate the importance of IEC-intrinsic canonical and non-canonical inflammasomes in host defense against Salmonella.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Caspase 1 / immunology*
  • Caspases, Initiator / immunology*
  • Epithelial Cells / enzymology
  • Epithelial Cells / immunology
  • Epithelial Cells / microbiology
  • Female
  • Immunity, Mucosal
  • Inflammasomes / immunology*
  • Inflammasomes / metabolism
  • Interferon-gamma / immunology
  • Intestinal Mucosa / enzymology
  • Intestinal Mucosa / immunology
  • Intestinal Mucosa / microbiology
  • Intestines / enzymology*
  • Intestines / immunology*
  • Intestines / microbiology
  • Lipopolysaccharides
  • Macrophages / immunology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Salmonella Infections / enzymology*
  • Salmonella Infections / immunology
  • Salmonella typhimurium / immunology*
  • Salmonella typhimurium / pathogenicity

Substances

  • Inflammasomes
  • Lipopolysaccharides
  • Interferon-gamma
  • Casp4 protein, mouse
  • Caspases, Initiator
  • Casp1 protein, mouse
  • Caspase 1