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J Exp Med. 2014 Sep 22;211(10):1957-68. doi: 10.1084/jem.20132130. Epub 2014 Sep 1.

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

Author information

1
Section of Cardiovascular Medicine, Department of Internal Medicine and the Yale Cardiovascular Research Center, Department of Immunobiology, Department of Cell Biology, and the Raymond and Beverly Sackler Foundation Cardiovascular Laboratory, Yale University School of Medicine, New Haven, CT 06511 Section of Cardiovascular Medicine, Department of Internal Medicine and the Yale Cardiovascular Research Center, Department of Immunobiology, Department of Cell Biology, and the Raymond and Beverly Sackler Foundation Cardiovascular Laboratory, Yale University School of Medicine, New Haven, CT 06511 Section of Cardiovascular Medicine, Department of Internal Medicine and the Yale Cardiovascular Research Center, Department of Immunobiology, Department of Cell Biology, and the Raymond and Beverly Sackler Foundation Cardiovascular Laboratory, Yale University School of Medicine, New Haven, CT 06511.
2
Section of Cardiovascular Medicine, Department of Internal Medicine and the Yale Cardiovascular Research Center, Department of Immunobiology, Department of Cell Biology, and the Raymond and Beverly Sackler Foundation Cardiovascular Laboratory, Yale University School of Medicine, New Haven, CT 06511 Section of Cardiovascular Medicine, Department of Internal Medicine and the Yale Cardiovascular Research Center, Department of Immunobiology, Department of Cell Biology, and the Raymond and Beverly Sackler Foundation Cardiovascular Laboratory, Yale University School of Medicine, New Haven, CT 06511.
3
Section of Cardiovascular Medicine, Department of Internal Medicine and the Yale Cardiovascular Research Center, Department of Immunobiology, Department of Cell Biology, and the Raymond and Beverly Sackler Foundation Cardiovascular Laboratory, Yale University School of Medicine, New Haven, CT 06511.
4
Department of Molecular Pathology, Universita Vita Salute School of Medicine, San Raffaele Scientific Institute, 20123 Milan, Italy.
5
Section of Cardiovascular Medicine, Department of Internal Medicine and the Yale Cardiovascular Research Center, Department of Immunobiology, Department of Cell Biology, and the Raymond and Beverly Sackler Foundation Cardiovascular Laboratory, Yale University School of Medicine, New Haven, CT 06511 Section of Cardiovascular Medicine, Department of Internal Medicine and the Yale Cardiovascular Research Center, Department of Immunobiology, Department of Cell Biology, and the Raymond and Beverly Sackler Foundation Cardiovascular Laboratory, Yale University School of Medicine, New Haven, CT 06511 Section of Cardiovascular Medicine, Department of Internal Medicine and the Yale Cardiovascular Research Center, Department of Immunobiology, Department of Cell Biology, and the Raymond and Beverly Sackler Foundation Cardiovascular Laboratory, Yale University School of Medicine, New Haven, CT 06511 jeffrey.bender@yale.edu.

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.

PMID:
25180062
PMCID:
PMC4172219
DOI:
10.1084/jem.20132130
[Indexed for MEDLINE]
Free PMC Article

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