title: Early VEGFR2 activation in response to flow is VEGF-dependent and mediated by MMP activity.
abstract: Although several potential mechanosensors/mechanotransducers have been proposed, the precise mechanisms by which ECs sense and respond to mechanical forces and translate them into biochemical signals remains unclear. Here, we report that two major ligand-dependent tyrosine autophosphorylation sites of VEGFR2, Y1175 and Y1214, are rapidly activated by shear stress in human coronary artery endothelial cells (HCAECs). Neutralizing antibody against VEGFR2 not only abrogates flow-induced phosphorylation of these tyrosine residues, but also has a marked inhibitory effect on downstream eNOS activation. In situ proximity ligation assay revealed that VEGF and VEGFR2 are closely associated in HCAECs, and more importantly, this association is increased with flow. Finally, we show that flow-induced VEGFR2 activation is attenuated in the presence of the broad spectrum matrix metalloproteinase (MMP) inhibitor, GM6001. Taken together, our results suggest that a ligand-dependent mechanism involving the activity of MMPs plays a key role in the early, shear stress-induced activation of VEGFR2.
authors.affiliation: La Jolla Bioengineering Institute, 3535 General Atomics Court, Suite 210, San Diego, CA 92121, USA. ndelapaz@ljbi.org
authors.forename: Nathaniel G
authors.initials: NG
authors.lastname: dela Paz
authors.forename: Benoît
authors.initials: B
authors.lastname: Melchior
authors.forename: John A
authors.initials: JA
authors.lastname: Frangos
mesh_terms: D057134:Antibodies, Neutralizing / Q000276:immunology; D015153:Blotting, Western; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D006801:Humans; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010766:Phosphorylation; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000276:immunology / Q000378:metabolism*
chemical_list: D057134:Antibodies, Neutralizing; D042461:Vascular Endothelial Growth Factor A; D052250:Nitric Oxide Synthase Type III; D040301:Vascular Endothelial Growth Factor Receptor-2; D020782:Matrix Metalloproteinases