title: Ligand-independent activation of vascular endothelial growth factor receptor 2 by fluid shear stress regulates activation of endothelial nitric oxide synthase.
abstract: Fluid shear stress generated by blood flowing over the endothelium is a major determinant of arterial tone, vascular remodeling, and atherogenesis. Nitric oxide (NO) produced by endothelial NO synthase (eNOS) plays an essential role in regulation of vascular function and structure by blood flow, but the molecular mechanisms that transduce mechanical force to eNOS activation are not well understood. In this study, we found that laminar flow (shear stress=12 dyne/cm2) rapidly activates vascular endothelial growth factor receptor 2 (VEGFR2) in a ligand-independent manner and leads to eNOS activation in cultured endothelial cells. Flow-stimulated VEGFR2 recruits phosphoinositide 3-kinase and mediates activation of Akt and eNOS. Inhibiting VEGFR2 kinase with selective inhibitors blocks flow-induced activation of Akt and eNOS and production of NO. Decreasing VEGFR2 expression with antisense VEGFR2 oligonucleotides significantly attenuates activation of Akt and eNOS. Furthermore, Src kinases are involved in flow-stimulated VEGFR2 because inhibiting Src kinases by PP2, a selective inhibitor for Src kinases, abolishes flow-induced VEGFR2 tyrosine phosphorylation and downstream signaling. Finally, we show that inhibiting VEGFR2 kinase significantly reduces flow-mediated NO-dependent arteriolar dilation in vivo. These data identify VEGFR2 as a key mechanotransducer that activates eNOS in response to blood flow.
authors.affiliation: Center for Cardiovascular Research and Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA. zheng-gen_jin@urmc.rochester.edu
authors.forename: Zheng-Gen
authors.initials: ZG
authors.lastname: Jin
authors.forename: Hiroto
authors.initials: H
authors.lastname: Ueba
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Tanimoto
authors.forename: Andreea O
authors.initials: AO
authors.lastname: Lungu
authors.forename: Mary D
authors.initials: MD
authors.lastname: Frame
authors.forename: Bradford C
authors.initials: BC
authors.lastname: Berk
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D016227:Benzoquinones; D001808:Blood Vessels / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D002610:Cheek / Q000098:blood supply; D006224:Cricetinae; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D039302:Integrin alphaVbeta3 / Q000276:immunology; D047029:Lactams, Macrocyclic; D008024:Ligands; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D011809:Quinones / Q000494:pharmacology; D017828:Rifabutin / Q000031:analogs & derivatives; D015398:Signal Transduction / Q000187:drug effects; D013314:Stress, Mechanical; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014664:Vasodilation / Q000187:drug effects; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D016227:Benzoquinones; D004791:Enzyme Inhibitors; D019833:Genistein; D039302:Integrin alphaVbeta3; D047029:Lactams, Macrocyclic; D008024:Ligands; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D011809:Quinones; D017828:Rifabutin; D040301:Vascular Endothelial Growth Factor Receptor-2; D019061:src-Family Kinases; C020754:herbimycin