STAT6 deficiency ameliorates severity of oxazolone colitis by decreasing expression of claudin-2 and Th2-inducing cytokines

J Immunol. 2013 Feb 15;190(4):1849-58. doi: 10.4049/jimmunol.1201373. Epub 2013 Jan 9.

Abstract

Patients suffering from ulcerative colitis (UC) exhibit chronic colonic inflammation caused by a dysregulated mucosal immune response and epithelial barrier disruption. Th2 cytokines, including IL-13, have been implicated in the pathogenesis of UC. IL-13 induces phosphorylation of STAT6, and we previously demonstrated increased epithelial p-STAT6 in children with UC. In this study, we investigated the role of STAT6 in oxazolone colitis, a murine model of UC, by inducing colitis in STAT6-deficient (STAT6(-/-)) and wild type (WT) mice. We observed increased epithelial cell, T cell, macrophage, and NKT cell STAT6 phosphorylation, as well as increased p-STAT6(+) IL-13-producing NKT cells, in colitic WT mice. Colitis was attenuated in STAT6(-/-) mice, with improvements in weight, colon length, and histopathology. There was decreased induction of the pore-forming tight junction protein claudin-2 in STAT6(-/-) mice. Similarly, short hairpin RNA STAT6 knockdown reduced claudin-2 induction and transepithelial resistance decrease in IL-13-treated human T84 cells. Tissue expression of IL-13, IFN-γ, IL-17, and IL-10 mRNA was similarly induced in WT and STAT6(-/-) colitic mice; however, we observed increased mRNA expression for the Th2-inducing cytokines IL-33 and thymic stromal lymphopoietin in WT mice with colitis, which was abrogated in STAT6(-/-) mice. Mesenteric lymph node cells from STAT6(-/-) mice with colitis exhibited reduced secretion of IL-4, IL-5, IL-13, and IFN-γ. IL-33 augmented mesenteric lymph node cell secretion of IL-5, IL-13, IL-6, and IFN-γ. These data implicate STAT6 in the pathogenesis of colitis in vivo with important roles in altering epithelial barrier function and regulating Th2-inducing cytokine production.

Publication types

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

MeSH terms

  • Adjuvants, Immunologic / administration & dosage
  • Adjuvants, Immunologic / adverse effects
  • Adjuvants, Immunologic / antagonists & inhibitors
  • Animals
  • Cell Line
  • Claudin-2 / antagonists & inhibitors*
  • Claudin-2 / biosynthesis
  • Claudin-2 / genetics
  • Colitis, Ulcerative / chemically induced
  • Colitis, Ulcerative / immunology*
  • Colitis, Ulcerative / prevention & control
  • Cytokines / antagonists & inhibitors*
  • Cytokines / biosynthesis
  • Cytokines / genetics
  • Disease Models, Animal
  • Down-Regulation / genetics
  • Down-Regulation / immunology*
  • Gene Expression Regulation / immunology
  • Haptens / administration & dosage
  • Haptens / adverse effects
  • Humans
  • Intestinal Mucosa / immunology
  • Intestinal Mucosa / metabolism
  • Intestinal Mucosa / pathology
  • Male
  • Mice
  • Mice, Knockout
  • Natural Killer T-Cells / immunology
  • Natural Killer T-Cells / metabolism
  • Natural Killer T-Cells / pathology
  • Oxazolone / administration & dosage*
  • Oxazolone / adverse effects
  • Oxazolone / antagonists & inhibitors
  • STAT6 Transcription Factor / deficiency*
  • STAT6 Transcription Factor / genetics
  • Severity of Illness Index*
  • Th2 Cells / immunology*
  • Th2 Cells / metabolism
  • Th2 Cells / pathology

Substances

  • Adjuvants, Immunologic
  • Claudin-2
  • Cytokines
  • Haptens
  • STAT6 Transcription Factor
  • Stat6 protein, mouse
  • Oxazolone