VEGF increases permeability of the endothelial cell monolayer by activation of PKB/akt, endothelial nitric-oxide synthase, and MAP kinase pathways.
VEGF is a key regulator of vascular permeability. However, its signaling pathways are incompletely understood. We tested the hypothesis that VEGF regulates endothelial cell (EC) permeability by activating PKB/akt, NOS, and MAP kinase dependent pathways using human umbilical vein EC (HUVEC). Permeability was measured from FITC-dextran 70-kDa flux across the EC monolayer at baseline and after VEGF at 0.034, 0.068, 1, 10, and 100 nM. VEGF increased HUVEC permeability to FITC-dextran in a dose-dependent manner. VEGF (1 nM) increased permeability from 3.9 x 10(-6) +/- 0.7 x 10(-6) to 14.0 x 10(-6) +/- 1.7 x 10(-6) cm/s (mean +/- SEM; P < 0.001). Permeability changes were also assessed after treatment with 1, 10, and 100 nM wortmannin (PI 3-kinase inhibitor); 0.01, 0.1, and 1.0 nM LY294002 (PI 3-kinase inhibitor); 200 microM l-NMMA (NOS inhibitor); 2.7 microM AG126 (p42/44(MAPK) inhibitor); and 0.006, 0.06, and 0.6 microM SB203580 (p38(MAPK) inhibitor). All inhibitors blocked VEGF-induced permeability changes. Our data demonstrate that (1) VEGF increases permeability of EC monolayers in a dose-dependent fashion, and (2) VEGF-induced permeability is mediated through PI-3 kinase-PKB, NOS, and MAP-kinase signaling cascades. These observations suggest that microvascular hyperpermeability associated with inflammation and vascular disease is mediated by activation of these EC signaling pathways.
Lal
B K
BK
Program in Vascular Biology, Department of Pharmacology & Physiology, UMDNJ-New Jersey Medical School, Newark, New Jersey 07103-2714, USA.
Varma
S
S
Pappas
P J
PJ
Hobson
R W
RW
Durán
W N
WN
D002199:Capillary Permeability / Q000187:drug effects*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D016228:Endothelial Growth Factors / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007231:Infant, Newborn; D007700:Kinetics; D008222:Lymphokines / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000187:drug effects / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000187:drug effects / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D014471:Umbilical Veins / Q000166:cytology; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D004791:Enzyme Inhibitors; D008222:Lymphokines; D011518:Proto-Oncogene Proteins; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D011505:Protein-Tyrosine Kinases; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt