PLoS Pathogens (2020-04-01)

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

  • Shauna M Crowley,
  • Xiao Han,
  • Joannie M Allaire,
  • Martin Stahl,
  • Isabella Rauch,
  • Leigh A Knodler,
  • Bruce A Vallance

DOI
https://doi.org/10.1371/journal.ppat.1008498
Journal volume & issue
Vol. 16, no. 4
p. e1008498

Abstract

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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.