Crucial roles of XCR1-expressing dendritic cells and the XCR1-XCL1 chemokine axis in intestinal immune homeostasis

Sci Rep. 2016 Mar 23:6:23505. doi: 10.1038/srep23505.

Abstract

Intestinal immune homeostasis requires dynamic crosstalk between innate and adaptive immune cells. Dendritic cells (DCs) exist as multiple phenotypically and functionally distinct sub-populations within tissues, where they initiate immune responses and promote homeostasis. In the gut, there exists a minor DC subset defined as CD103(+)CD11b(-) that also expresses the chemokine receptor XCR1. In other tissues, XCR1(+) DCs cross-present antigen and contribute to immunity against viruses and cancer, however the roles of XCR1(+) DCs and XCR1 in the intestine are unknown. We showed that mice lacking XCR1(+) DCs are specifically deficient in intraepithelial and lamina propria (LP) T cell populations, with remaining T cells exhibiting an atypical phenotype and being prone to death, and are also more susceptible to chemically-induced colitis. Mice deficient in either XCR1 or its ligand, XCL1, similarly possess diminished intestinal T cell populations, and an accumulation of XCR1(+) DCs in the gut. Combined with transcriptome and surface marker expression analysis, these observations lead us to hypothesise that T cell-derived XCL1 facilitates intestinal XCR1(+) DC activation and migration, and that XCR1(+) DCs in turn provide support for T cell survival and function. Thus XCR1(+) DCs and the XCR1/XCL1 chemokine axis have previously-unappreciated roles in intestinal immune homeostasis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Movement
  • Cell Proliferation
  • Cell Survival
  • Cells, Cultured
  • Chemokines, C / deficiency
  • Chemokines, C / metabolism*
  • Cross-Priming
  • Dendritic Cells / immunology
  • Dendritic Cells / physiology*
  • Gene Expression Profiling / methods
  • Gene Expression Regulation
  • Homeostasis
  • Intestines / cytology
  • Intestines / immunology*
  • Mice
  • Receptors, Chemokine / deficiency
  • Receptors, Chemokine / metabolism*
  • T-Lymphocytes / cytology*
  • T-Lymphocytes / immunology

Substances

  • Chemokines, C
  • Receptors, Chemokine
  • XC chemokine receptor 1, mouse
  • Xcl1 protein, mouse