Intestinal CCL11 and eosinophilic inflammation is regulated by myeloid cell-specific RelA/p65 in mice

J Immunol. 2013 May 1;190(9):4773-85. doi: 10.4049/jimmunol.1200057. Epub 2013 Apr 5.

Abstract

In inflammatory bowel diseases (IBDs), particularly ulcerative colitis, intestinal macrophages (MΦs), eosinophils, and the eosinophil-selective chemokine CCL11, have been associated with disease pathogenesis. MΦs, a source of CCL11, have been reported to be of a mixed classical (NF-κB-mediated) and alternatively activated (STAT-6-mediated) phenotype. The importance of NF-κB and STAT-6 pathways to the intestinal MΦ/CCL11 response and eosinophilic inflammation in the histopathology of experimental colitis is not yet understood. Our gene array analyses demonstrated elevated STAT-6- and NF-κB-dependent genes in pediatric ulcerative colitis colonic biopsies. Dextran sodium sulfate (DSS) exposure induced STAT-6 and NF-κB activation in mouse intestinal F4/80(+)CD11b(+)Ly6C(hi) (inflammatory) MΦs. DSS-induced CCL11 expression, eosinophilic inflammation, and histopathology were attenuated in RelA/p65(Δmye) mice, but not in the absence of STAT-6. Deletion of p65 in myeloid cells did not affect inflammatory MΦ recruitment or alter apoptosis, but did attenuate LPS-induced cytokine production (IL-6) and Ccl11 expression in purified F4/80(+)CD11b(+)Ly6C(hi) inflammatory MΦs. Molecular and cellular analyses revealed a link between expression of calprotectin (S100a8/S100a9), Ccl11 expression, and eosinophil numbers in the DSS-treated colon. In vitro studies of bone marrow-derived MΦs showed calprotectin-induced CCL11 production via a p65-dependent mechanism. Our results indicate that myeloid cell-specific NF-κB-dependent pathways play an unexpected role in CCL11 expression and maintenance of eosinophilic inflammation in experimental colitis. These data indicate that targeting myeloid cells and NF-κB-dependent pathways may be of therapeutic benefit for the treatment of eosinophilic inflammation and histopathology in IBD.

Publication types

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

MeSH terms

  • Animals
  • Apoptosis / genetics
  • Chemokine CCL11 / genetics
  • Chemokine CCL11 / metabolism*
  • Colitis, Ulcerative / genetics
  • Colitis, Ulcerative / metabolism
  • Colitis, Ulcerative / pathology
  • Colon / metabolism
  • Colon / pathology
  • Eosinophils / metabolism*
  • Eosinophils / pathology
  • Female
  • Gene Expression
  • Humans
  • Inflammation / genetics
  • Inflammation / metabolism*
  • Inflammation / pathology
  • Interleukin-4 / genetics
  • Interleukin-4 / metabolism
  • Interleukin-6 / genetics
  • Interleukin-6 / metabolism
  • Intestinal Mucosa / metabolism*
  • Intestines / pathology
  • Macrophages / metabolism
  • Macrophages / pathology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Myeloid Cells / metabolism*
  • Myeloid Cells / pathology
  • NF-kappa B / genetics
  • NF-kappa B / metabolism
  • STAT6 Transcription Factor / genetics
  • STAT6 Transcription Factor / metabolism
  • Transcription Factor RelA / genetics
  • Transcription Factor RelA / metabolism*

Substances

  • Ccl11 protein, mouse
  • Chemokine CCL11
  • Interleukin-6
  • NF-kappa B
  • Rela protein, mouse
  • STAT6 Transcription Factor
  • Stat6 protein, mouse
  • Transcription Factor RelA
  • Interleukin-4

Supplementary concepts

  • Pediatric ulcerative colitis