Plasminogen activator inhibitor-1 inhibits angiogenic signaling by uncoupling vascular endothelial growth factor receptor-2-αVβ3 integrin cross talk.
OBJECTIVE
Plasminogen activator inhibitor-1 (PAI-1) regulates angiogenesis via effects on extracellular matrix proteolysis and cell adhesion. However, no previous study has implicated PAI-1 in controlling vascular endothelial growth factor (VEGF) signaling. We tested the hypothesis that PAI-1 downregulates VEGF receptor-2 (VEGFR-2) activation by inhibiting a vitronectin-dependent cooperative binding interaction between VEGFR-2 and αVβ3.


RESULTS
We studied effects of PAI-1 on VEGF signaling in human umbilical vein endothelial cells. PAI-1 inhibited VEGF-induced phosphorylation of VEGFR-2 in human umbilical vein endothelial cells grown on vitronectin, but not on fibronectin or collagen. PAI-1 inhibited the binding of VEGFR-2 to β3 integrin, VEGFR-2 endocytosis, and intracellular signaling pathways downstream of VEGFR-2. The anti-VEGF effect of PAI-1 was mediated by 2 distinct pathways, one requiring binding to vitronectin and another requiring binding to very low-density lipoprotein receptor. PAI-1 inhibited VEGF-induced angiogenesis in vitro and in vivo, and pharmacological inhibition of PAI-1 promoted collateral arteriole development and recovery of hindlimb perfusion after femoral artery interruption.


CONCLUSIONS
PAI-1 inhibits activation of VEGFR-2 by VEGF by disrupting a vitronectin-dependent proangiogenic binding interaction involving αVβ3 and VEGFR-2. These results broaden our understanding of the roles of PAI-1, vitronectin, and endocytic receptors in regulating VEGFR-2 activation and suggest novel therapeutic strategies for regulating VEGF signaling.
From the Departments of Internal Medicine and Medical Pharmacology and Physiology (J.W., T.L.S., M.L., W.P.F.), the Research Service, Harry S. Truman Memorial Veterans Hospital (W.P.F.), University of Missouri School of Medicine, Columbia; the Drug Discovery Research Center, Luzhou Medical College, Luzhou, Sichuan, China (J.W., M.L., L.W., R.L., M.R., J.X., Z.Z., W.M., T.L.); and the Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (D.A.L.). wuji@missouri.edu.
Jianbo
J
Wu
From the Departments of Internal Medicine and Medical Pharmacology and Physiology (J.W., T.L.S., M.L., W.P.F.), the Research Service, Harry S. Truman Memorial Veterans Hospital (W.P.F.), University of Missouri School of Medicine, Columbia; the Drug Discovery Research Center, Luzhou Medical College, Luzhou, Sichuan, China (J.W., M.L., L.W., R.L., M.R., J.X., Z.Z., W.M., T.L.); and the Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (D.A.L.).
Tammy L
TL
Strawn
From the Departments of Internal Medicine and Medical Pharmacology and Physiology (J.W., T.L.S., M.L., W.P.F.), the Research Service, Harry S. Truman Memorial Veterans Hospital (W.P.F.), University of Missouri School of Medicine, Columbia; the Drug Discovery Research Center, Luzhou Medical College, Luzhou, Sichuan, China (J.W., M.L., L.W., R.L., M.R., J.X., Z.Z., W.M., T.L.); and the Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (D.A.L.).
Mao
M
Luo
From the Departments of Internal Medicine and Medical Pharmacology and Physiology (J.W., T.L.S., M.L., W.P.F.), the Research Service, Harry S. Truman Memorial Veterans Hospital (W.P.F.), University of Missouri School of Medicine, Columbia; the Drug Discovery Research Center, Luzhou Medical College, Luzhou, Sichuan, China (J.W., M.L., L.W., R.L., M.R., J.X., Z.Z., W.M., T.L.); and the Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (D.A.L.).
Liqun
L
Wang
From the Departments of Internal Medicine and Medical Pharmacology and Physiology (J.W., T.L.S., M.L., W.P.F.), the Research Service, Harry S. Truman Memorial Veterans Hospital (W.P.F.), University of Missouri School of Medicine, Columbia; the Drug Discovery Research Center, Luzhou Medical College, Luzhou, Sichuan, China (J.W., M.L., L.W., R.L., M.R., J.X., Z.Z., W.M., T.L.); and the Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (D.A.L.).
Rong
R
Li
From the Departments of Internal Medicine and Medical Pharmacology and Physiology (J.W., T.L.S., M.L., W.P.F.), the Research Service, Harry S. Truman Memorial Veterans Hospital (W.P.F.), University of Missouri School of Medicine, Columbia; the Drug Discovery Research Center, Luzhou Medical College, Luzhou, Sichuan, China (J.W., M.L., L.W., R.L., M.R., J.X., Z.Z., W.M., T.L.); and the Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (D.A.L.).
Meiping
M
Ren
From the Departments of Internal Medicine and Medical Pharmacology and Physiology (J.W., T.L.S., M.L., W.P.F.), the Research Service, Harry S. Truman Memorial Veterans Hospital (W.P.F.), University of Missouri School of Medicine, Columbia; the Drug Discovery Research Center, Luzhou Medical College, Luzhou, Sichuan, China (J.W., M.L., L.W., R.L., M.R., J.X., Z.Z., W.M., T.L.); and the Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (D.A.L.).
Jiyi
J
Xia
From the Departments of Internal Medicine and Medical Pharmacology and Physiology (J.W., T.L.S., M.L., W.P.F.), the Research Service, Harry S. Truman Memorial Veterans Hospital (W.P.F.), University of Missouri School of Medicine, Columbia; the Drug Discovery Research Center, Luzhou Medical College, Luzhou, Sichuan, China (J.W., M.L., L.W., R.L., M.R., J.X., Z.Z., W.M., T.L.); and the Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (D.A.L.).
Zhuo
Z
Zhang
From the Departments of Internal Medicine and Medical Pharmacology and Physiology (J.W., T.L.S., M.L., W.P.F.), the Research Service, Harry S. Truman Memorial Veterans Hospital (W.P.F.), University of Missouri School of Medicine, Columbia; the Drug Discovery Research Center, Luzhou Medical College, Luzhou, Sichuan, China (J.W., M.L., L.W., R.L., M.R., J.X., Z.Z., W.M., T.L.); and the Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (D.A.L.).
Weizhong
W
Ma
From the Departments of Internal Medicine and Medical Pharmacology and Physiology (J.W., T.L.S., M.L., W.P.F.), the Research Service, Harry S. Truman Memorial Veterans Hospital (W.P.F.), University of Missouri School of Medicine, Columbia; the Drug Discovery Research Center, Luzhou Medical College, Luzhou, Sichuan, China (J.W., M.L., L.W., R.L., M.R., J.X., Z.Z., W.M., T.L.); and the Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (D.A.L.).
Tingting
T
Luo
From the Departments of Internal Medicine and Medical Pharmacology and Physiology (J.W., T.L.S., M.L., W.P.F.), the Research Service, Harry S. Truman Memorial Veterans Hospital (W.P.F.), University of Missouri School of Medicine, Columbia; the Drug Discovery Research Center, Luzhou Medical College, Luzhou, Sichuan, China (J.W., M.L., L.W., R.L., M.R., J.X., Z.Z., W.M., T.L.); and the Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (D.A.L.).
Daniel A
DA
Lawrence
From the Departments of Internal Medicine and Medical Pharmacology and Physiology (J.W., T.L.S., M.L., W.P.F.), the Research Service, Harry S. Truman Memorial Veterans Hospital (W.P.F.), University of Missouri School of Medicine, Columbia; the Drug Discovery Research Center, Luzhou Medical College, Luzhou, Sichuan, China (J.W., M.L., L.W., R.L., M.R., J.X., Z.Z., W.M., T.L.); and the Department of Internal Medicine, University of Michigan Medical School, Ann Arbor (D.A.L.).
William P
WP
Fay
D000818:Animals; D002448:Cell Adhesion; D002465:Cell Movement; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004705:Endocytosis; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D006614:Hindlimb; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007210:Indoleacetic Acids / Q000008:administration & dosage; D039302:Integrin alphaVbeta3 / Q000378:metabolism*; D007511:Ischemia / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control; D008297:Male; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018482:Muscle, Skeletal / Q000098:blood supply*; D009154:Mutation; D018919:Neovascularization, Physiologic / Q000187:drug effects; D010766:Phosphorylation; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D020239:Receptor Cross-Talk / Q000187:drug effects; D011973:Receptors, LDL / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000008:administration & dosage; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014162:Transfection; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism*; D019096:Vitronectin / Q000172:deficiency / Q000235:genetics
D007210:Indoleacetic Acids; D039302:Integrin alphaVbeta3; D017395:Plasminogen Activator Inhibitor 1; D011973:Receptors, LDL; D011994:Recombinant Proteins; C051321:SERPINE1 protein, human; D015842:Serine Proteinase Inhibitors; C036053:VLDL receptor; D019096:Vitronectin; C488103:tiplaxtinin; C000588866:KDR protein, human; D040301:Vascular Endothelial Growth Factor Receptor-2
plasminogen activator inhibitor-1; vascular endothelial growth factor A; very low-density lipoprotein receptor; vitronectin