Specific bioactivity of IL-22 in intestinal cells as revealed by the expression of IL-22RA1 in Mandarin fish, Siniperca chuatsi

Dev Comp Immunol. 2021 Aug:121:104107. doi: 10.1016/j.dci.2021.104107. Epub 2021 Apr 18.

Abstract

IL-22, a multifunctional cytokine, acts as an important regulator in host immunity in mammals. IL-22 homologues have been characterized in several species of fish, with its expression found in multiple tissues/cells in fish, but its target cells have not been fully analyzed. In the present research, different organ/tissue isolated cells were examined for the expression of IL-22 and the induced IL-22 responses in mandarin fish. The mandarin fish IL-22 was found to be expressed in all these tested cells with high basal expression in intestinal cells. The HKLs showed low basal expression but significant increase in expression of IL-22 after LPS treatment or bacterial infection. Only intestinal cells showed response to IL-22 by enhanced expression of hepcidin, LEAP2 and IL-22BP, with unresponsiveness observed in other tested cells, which indicated the cell-specificity of IL-22 bioactivity in mandarin fish. One of the heterodimeric receptor components for IL-22, the IL-22RA1, was cloned in mandarin fish, with four tandem fibronectin type III (FNIII) domains identified in its extracellular part. IL-22RA1 exhibited an intestinal cell-specific expression pattern, although another receptor component of IL-22, IL-10R2, displayed constitutive expressions in all these tested cells. The present study reveals that the mandarin fish IL-22 exhibits its bioactivity in a cell-specific manner in intestinal cells, which is reflected in the restrictive expression of its receptor unit, IL-22RA1.

Keywords: Expression; IL-22; IL-22RA1; Mandarin fish.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antimicrobial Cationic Peptides / metabolism
  • Cloning, Molecular
  • Epithelial Cells / immunology
  • Epithelial Cells / metabolism
  • Fish Proteins / genetics
  • Fish Proteins / metabolism*
  • Fishes / genetics
  • Fishes / immunology*
  • Fishes / metabolism
  • Hepcidins / metabolism
  • Interleukin-22
  • Interleukins / metabolism*
  • Intestinal Mucosa / cytology
  • Receptors, Interleukin / genetics
  • Receptors, Interleukin / metabolism*

Substances

  • Antimicrobial Cationic Peptides
  • Fish Proteins
  • Hepcidins
  • Interleukins
  • Receptors, Interleukin
  • interleukin-22 receptor