Chemokine-coupled β2 integrin-induced macrophage Rac2-myosin IIA interaction regulates VEGF-A mRNA stability and arteriogenesis

Alan R. Morrison, Timur O. Yarovinsky, Bryan D. Young, Filipa Moraes, Tyler D. Ross, Nicolle Ceneri, Jiasheng Zhang, Zhen W. Zhuang, Albert J. Sinusas, Ruggero Pardi, Martin A. Schwartz, Michael Simons, Jeffrey R. Bender

Research output: Contribution to journalArticlepeer-review

Abstract

Myeloid cells are important contributors to arteriogenesis, but their key molecular triggers and cellular effectors are largely unknown. We report, in inflammatory monocytes, that the combination of chemokine receptor (CCR2) and adhesion receptor (β2 integrin) engagement leads to an interaction between activated Rac2 and Myosin 9 (Myh9), the heavy chain of Myosin IIA, resulting in augmented vascular endothelial growth factor A (VEGF-A) expression and induction of arteriogenesis. In human monocytes, CCL2 stimulation coupled to ICAM-1 adhesion led to rapid nuclear-to-cytosolic translocation of the RNA-binding protein HuR. This activation of HuR and its stabilization of VEGF-A mRNA were Rac2-dependent, and proteomic analysis for Rac2 interactors identified the 226 kD protein Myh9. The level of induced Rac2-Myh9 interaction strongly correlated with the degree of HuR translocation. CCL2-coupled ICAM-1 adhesion-driven HuR translocation and consequent VEGF-A mRNA stabilization were absent in Myh9-/- macrophages. Macrophage VEGF-A production, ischemic tissue VEGF-A levels, and flow recovery to hind limb ischemia were impaired in myeloid-specific Myh9-/- mice, despite preserved macrophage recruitment to the ischemic muscle. Micro-CT arteriography determined the impairment to be defective induced arteriogenesis, whereas developmental vasculogenesis was unaffected. These results place the macrophage at the center of ischemia-induced arteriogenesis, and they establish a novel role for Myosin IIA in signal transduction events modulating VEGF-A expression in tissue.

Original languageEnglish
Pages (from-to)1957-1968
Number of pages12
JournalJournal of Experimental Medicine
Volume211
Issue number10
DOIs
Publication statusPublished - 2014

ASJC Scopus subject areas

  • Immunology
  • Immunology and Allergy
  • Medicine(all)

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