Thrombospondin-1 is a CD47-dependent endogenous inhibitor of hydrogen sulfide signaling in T cell activation

Matrix Biol. 2013 Aug 8;32(6):316-24. doi: 10.1016/j.matbio.2013.02.009. Epub 2013 Mar 13.

Abstract

Thrombospondin-1 is a potent suppressor of T cell activation via its receptor CD47. However, the precise mechanism for this inhibition remains unclear. Because H2S is an endogenous potentiator of T cell activation and is necessary for full T cell activation, we hypothesized that thrombospondin-1 signaling through CD47 inhibits T cell activation by antagonizing H2S signaling. Primary T cells from thrombospondin-1 null mice were more sensitive to H2S-dependent activation assessed by proliferation and induction of interleukin-2 and CD69 mRNAs. Exogenous thrombospondin-1 inhibited H2S responses in wild type and thrombospondin-1 null T cells but enhanced the same responses in CD47 null T cells. Fibronectin, which shares integrin and glycosaminoglycan binding properties with thrombospondin-1 but not CD47 binding, did not inhibit H2S signaling. A CD47-binding peptide derived from thrombospondin-1 inhibited H2S-induced activation, whereas two other functional sequences from thrombospondin-1 enhanced H2S signaling. Therefore, engaging CD47 is necessary and sufficient for thrombospondin-1 to inhibit H2S-dependent T cell activation. H2S stimulated T cell activation by potentiating MEK-dependent ERK phosphorylation, and thrombospondin-1 inhibited this signaling in a CD47-dependent manner. Thrombospondin-1 also limited activation-dependent T cell expression of the H2S biosynthetic enzymes cystathionine β-synthase and cystathionine γ-lyase, thereby limiting the autocrine role of H2S in T cell activation. Thus, thrombospondin-1 signaling through CD47 is the first identified endogenous inhibitor of H2S signaling and constitutes a novel mechanism that negatively regulates T cell activation.

Keywords: CBS; CD47; CSE; ERK; Extracellular signal-regulated kinase; Extracellular signal-regulated kinases; Hydrogen sulfide; IL-2; Interleukin-2; MEK; Mitogen-activated protein kinase kinase; Redox signaling; T cell antigen receptor; T lymphocytes; TCR; TSP1; Thrombospondin-1; cystathionine β-synthase; cystathionine γ-lyase.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Animals
  • Antigens, CD / genetics
  • Antigens, CD / metabolism
  • Antigens, Differentiation, T-Lymphocyte / genetics
  • Antigens, Differentiation, T-Lymphocyte / metabolism
  • Binding Sites
  • CD47 Antigen / genetics
  • CD47 Antigen / metabolism*
  • Cystathionine beta-Synthase / genetics
  • Cystathionine beta-Synthase / metabolism
  • Cystathionine gamma-Lyase / genetics
  • Cystathionine gamma-Lyase / metabolism
  • Fibronectins / genetics
  • Fibronectins / metabolism
  • Fibronectins / pharmacology
  • Gene Expression Regulation
  • Humans
  • Hydrogen Sulfide / metabolism*
  • Hydrogen Sulfide / pharmacology
  • Interleukin-2 / genetics
  • Interleukin-2 / metabolism
  • Lectins, C-Type / genetics
  • Lectins, C-Type / metabolism
  • Lymphocyte Activation / drug effects*
  • MAP Kinase Signaling System / drug effects*
  • Mice
  • Mice, Knockout
  • Phosphorylation
  • Primary Cell Culture
  • Protein Binding
  • T-Lymphocytes / cytology
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / metabolism*
  • Thrombospondin 1 / genetics
  • Thrombospondin 1 / metabolism*
  • Thrombospondin 1 / pharmacology

Substances

  • Antigens, CD
  • Antigens, Differentiation, T-Lymphocyte
  • CD47 Antigen
  • CD69 antigen
  • Cd47 protein, mouse
  • Fibronectins
  • Interleukin-2
  • Lectins, C-Type
  • Thrombospondin 1
  • thrombospondin-1, mouse
  • Cystathionine beta-Synthase
  • Cystathionine gamma-Lyase
  • Hydrogen Sulfide