Semaphorin 4A exerts a proangiogenic effect by enhancing vascular endothelial growth factor-A expression in macrophages

J Immunol. 2012 Apr 15;188(8):4081-92. doi: 10.4049/jimmunol.1101435. Epub 2012 Mar 21.

Abstract

The axon guidance cues semaphorins (Semas) and their receptors plexins have been shown to regulate both physiological and pathological angiogenesis. Sema4A plays an important role in the immune system by inducing T cell activation, but to date, the role of Sema4A in regulating the function of macrophages during the angiogenic and inflammatory processes remains unclear. In this study, we show that macrophage activation by TLR ligands LPS and polyinosinic-polycytidylic acid induced a time-dependent increase of Sema4A and its receptors PlexinB2 and PlexinD1. Moreover, in a thioglycollate-induced peritonitis mouse model, Sema4A was detected in circulating Ly6C(high) inflammatory monocytes and peritoneal macrophages. Acting via PlexinD1, exogenous Sema4A strongly increased macrophage migration. Of note, Sema4A-activated PlexinD1 enhanced the expression of vascular endothelial growth factor-A, but not of inflammatory chemokines. Sema4A-stimulated macrophages were able to activate vascular endothelial growth factor receptor-2 and the PI3K/serine/threonine kinase Akt pathway in endothelial cells and to sustain their migration and in vivo angiogenesis. Remarkably, in an in vivo cardiac ischemia/reperfusion mouse model, Sema4A was highly expressed in macrophages recruited at the injured area. We conclude that Sema4A activates a specialized and restricted genetic program in macrophages able to sustain angiogenesis and participates in their recruitment and activation in inflammatory injuries.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Movement
  • Chemokines / biosynthesis
  • Chemokines / immunology
  • Chick Embryo
  • Chorioallantoic Membrane / blood supply
  • Disease Models, Animal
  • Endothelial Cells / drug effects
  • Endothelial Cells / immunology
  • Endothelial Cells / pathology
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Lipopolysaccharides / pharmacology
  • Macrophage Activation
  • Macrophages, Peritoneal / immunology*
  • Macrophages, Peritoneal / pathology
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / immunology
  • Mice
  • Myocardium / pathology
  • Neovascularization, Physiologic*
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / immunology
  • Peritonitis / immunology
  • Peritonitis / metabolism
  • Peritonitis / pathology
  • Reperfusion Injury / immunology
  • Reperfusion Injury / metabolism
  • Reperfusion Injury / pathology
  • Semaphorins / pharmacology
  • Semaphorins / physiology*
  • Signal Transduction
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / immunology*
  • Vascular Endothelial Growth Factor A / metabolism

Substances

  • Chemokines
  • Intracellular Signaling Peptides and Proteins
  • Lipopolysaccharides
  • Membrane Glycoproteins
  • Nerve Tissue Proteins
  • Plxnb2 protein, mouse
  • Plxnd1 protein, mouse
  • Sema4A protein, mouse
  • Semaphorins
  • Vascular Endothelial Growth Factor A