Regulation of microglial phagocytosis and inflammatory gene expression by Gas6 acting on the Axl/Mer family of tyrosine kinases Academic Article uri icon

Overview

MeSH Major

  • Inflammation
  • Intercellular Signaling Peptides and Proteins
  • Microglia
  • Oncogene Proteins
  • Phagocytosis
  • Proto-Oncogene Proteins
  • Receptor Protein-Tyrosine Kinases

abstract

  • Removal of apoptotic cells is an essential process for normal development and tissue maintenance. Importantly, apoptotic cells stimulate their phagocytosis by macrophages while actively suppressing inflammatory responses. Growth arrest specific gene 6 (Gas6) is involved in this process, bridging phosphatidylserine residues on the surface of apoptotic cells to the Axl/Mer family of tyrosine kinases which stimulate phagocytosis. Animals with mutations or loss of these receptors exhibit phenotypes reflective of impaired phagocytosis and a hyperactive immune response. We report that Gas6 induces phagocytosis in microglia through a novel non-classical phagocytic mechanism. Gas6 stimulates a type-II-related phagocytic response, but requires Vav phosphorylation and Rac activation, distinguishing it from the classical type II mechanism. Importantly, Gas6 suppressed lipopolysaccharide-induced expression of the inflammatory molecules IL-1beta and iNOS. Gas6 inhibited iNOS expression through suppression of promoter activity. The present data provide direct evidence for the role of Gas6 receptors in mediating an anti-inflammatory response to ligands found on apoptotic cells with the simultaneous stimulation of phagocytosis. These data provide a mechanistic explanation for the phenotype observed in animals lacking Axl/Mer receptors.

publication date

  • June 2008

Research

keywords

  • Academic Article

Identity

Language

  • eng

PubMed Central ID

  • PMC3653274

Digital Object Identifier (DOI)

  • 10.1007/s11481-007-9090-2

PubMed ID

  • 18247125

Additional Document Info

start page

  • 130

end page

  • 40

volume

  • 3

number

  • 2