Interleukin-37 regulates innate immune signaling in human and mouse colonic organoids

Sci Rep. 2021 Apr 15;11(1):8206. doi: 10.1038/s41598-021-87592-2.

Abstract

Intestinal epithelial cells (IEC) reside in close proximity to the gut microbiota and are hypo-responsive to bacterial products, likely to prevent maladaptive inflammatory responses. This is in part due to their strong expression of Single Ig IL-1 related receptor (SIGIRR), a negative regulator of interleukin (IL)-1 and toll-like receptor signaling. IL-37 is an anti-inflammatory cytokine that inhibits innate signaling in diverse cells by signaling through SIGIRR. Despite the strong expression of SIGIRR by IEC, few studies have examined whether IL-37 can suppress their innate immune signaling. We characterized innate immune responses of human and murine colonoids to bacteria (FliC, LPS) and host (IL-1β) products and the role of IL-37/SIGIRR in regulating these responses. We demonstrated that human colonoids responded only to FliC, but not to LPS or IL-1β. While colonoids derived from different donors displayed significant inter-individual variability in the magnitude of their innate responses to FliC stimulation, all colonoids released a variety of chemokines. Interestingly, IL-37 attenuated these responses through inhibition of p38 and NFκB signaling pathways. We determined that this suppression by IL-37 was SIGIRR dependent, in murine organoids. Along with species-specific differences in IEC innate responses, we show that IL-37 can promote IEC hypo-responsiveness by suppressing inflammatory signaling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Animals
  • Cells, Cultured
  • Child
  • Colon / immunology*
  • Colon / metabolism
  • Colon / pathology
  • Humans
  • Immunity, Innate / genetics*
  • Interleukin-1 / physiology*
  • Male
  • Mice
  • Mice, Knockout
  • Organoids / immunology*
  • Organoids / metabolism
  • Organoids / pathology
  • Signal Transduction / genetics
  • Signal Transduction / immunology
  • Young Adult

Substances

  • IL37 protein, human
  • Interleukin-1

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