SARM regulates CCL5 production in macrophages by promoting the recruitment of transcription factors and RNA polymerase II to the Ccl5 promoter

J Immunol. 2014 May 15;192(10):4821-32. doi: 10.4049/jimmunol.1302980. Epub 2014 Apr 7.

Abstract

The four Toll/IL-1R domain-containing adaptor proteins MyD88, MAL, TRIF, and TRAM are well established as essential mediators of TLR signaling and gene induction following microbial detection. In contrast, the function of the fifth, most evolutionarily conserved Toll/IL-1R adaptor, sterile α and HEAT/Armadillo motif-containing protein (SARM), has remained more elusive. Recent studies of Sarm(-/-) mice have highlighted a role for SARM in stress-induced neuronal cell death and immune responses in the CNS. However, whether SARM has a role in immune responses in peripheral myeloid immune cells is less clear. Thus, we characterized TLR-induced cytokine responses in SARM-deficient murine macrophages and discovered a requirement for SARM in CCL5 production, whereas gene induction of TNF, IL-1β, CCL2, and CXCL10 were SARM-independent. SARM was not required for TLR-induced activation of MAPKs or of transcription factors implicated in CCL5 induction, namely NF-κB and IFN regulatory factors, nor for Ccl5 mRNA stability or splicing. However, SARM was critical for the recruitment of transcription factors and of RNA polymerase II to the Ccl5 promoter. Strikingly, the requirement of SARM for CCL5 induction was not restricted to TLR pathways, as it was also apparent in cytosolic RNA and DNA responses. Thus, this study identifies a new role for SARM in CCL5 expression in macrophages.

Publication types

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

MeSH terms

  • Animals
  • Armadillo Domain Proteins / genetics
  • Armadillo Domain Proteins / immunology*
  • Armadillo Domain Proteins / metabolism
  • Chemokine CCL2 / genetics
  • Chemokine CCL2 / immunology
  • Chemokine CCL2 / metabolism
  • Chemokine CCL5 / biosynthesis
  • Chemokine CCL5 / genetics
  • Chemokine CCL5 / immunology*
  • Chemokine CXCL10 / genetics
  • Chemokine CXCL10 / immunology
  • Chemokine CXCL10 / metabolism
  • Cytoskeletal Proteins / genetics
  • Cytoskeletal Proteins / immunology*
  • Cytoskeletal Proteins / metabolism
  • Gene Expression Regulation / physiology
  • Interferon Regulatory Factors / genetics
  • Interferon Regulatory Factors / immunology*
  • Interferon Regulatory Factors / metabolism
  • Interleukin-1beta / genetics
  • Interleukin-1beta / immunology
  • Interleukin-1beta / metabolism
  • Macrophages, Peritoneal / cytology
  • Macrophages, Peritoneal / immunology*
  • Macrophages, Peritoneal / metabolism
  • Mice
  • Mice, Knockout
  • NF-kappa B / genetics
  • NF-kappa B / immunology*
  • NF-kappa B / metabolism
  • Promoter Regions, Genetic / immunology*
  • RNA Polymerase II / genetics
  • RNA Polymerase II / immunology*
  • RNA Polymerase II / metabolism
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / immunology
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • Armadillo Domain Proteins
  • Ccl2 protein, mouse
  • Ccl5 protein, mouse
  • Chemokine CCL2
  • Chemokine CCL5
  • Chemokine CXCL10
  • Cxcl10 protein, mouse
  • Cytoskeletal Proteins
  • Interferon Regulatory Factors
  • Interleukin-1beta
  • NF-kappa B
  • SARM1 protein, mouse
  • Tumor Necrosis Factor-alpha
  • RNA Polymerase II