Opposing effect of angiopoietin-1 on VEGF-mediated disruption of endothelial cell-cell interactions requires activation of PKC beta.
Angiopoietin-1 (Ang1) and vascular endothelial growth factor (VEGF) cooperate in migration and survival of endothelial cells by activation of phosphatidylinositol-3 (PI-3) kinase and mitogen activating protein (MAP) kinase pathways. However, Ang1 opposes the effect of VEGF on vascular permeability. We found that Ang1 also blocks VEGF-mediated diffusion of fluoresin isothiocyanate (FITC)-labeled albumin across an endothelial cell monolayer. VEGF-mediated vascular permeability has been attributed, in part, to activation of phospholipase A(2) and subsequent formation of platelet activating factor. However, Ang1 had no effect on VEGF-induced activation of phospholipase A(2) or the release of arachidonic acid. VEGF-mediated permeability was associated with disruption of endothelial cell junctional complexes, dissociation of beta-catenin from VE-cadherin, and accumulation of beta-catenin in the cytosol. In contrast, Ang1 enhanced the interaction of beta-catenin with VE-cadherin and impaired VEGF-mediated dissociation of this complex. Ang1 also blocked VEGF-induced translocation of protein kinase C (PKC) and beta2 to the membrane, but had no effect on activation of PKC alpha. In addition, staurosporine and a PKC beta inhibitor, LY379196, blocked VEGF-mediated dissociation of beta-catenin from VE-cadherin, diffusion of albumin across the endothelial cell monolayer, and translocation of PKC beta isoforms. These data indicate that VEGF-mediated disruption of endothelial cell-cell interactions requires activation of PKC beta isoforms and that this pathway is blocked by Ang1.
BIDMC Genomic Center, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02115, USA. ywang3@bidmc.harvard.edu
Yihong
Y
Wang
Sergey
S
Pampou
Koshi
K
Fujikawa
Lyuba
L
Varticovski
D000418:Albumins / Q000378:metabolism; D042683:Angiopoietin-1 / Q000378:metabolism*; D000818:Animals; D015703:Antigens, CD; D015820:Cadherins / Q000378:metabolism; D002199:Capillary Permeability; D002450:Cell Communication / Q000502:physiology*; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D004789:Enzyme Activation; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D010972:Platelet Activating Factor / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D015534:Trans-Activators / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D051176:beta Catenin; D000099152:Cadherin 5
D000418:Albumins; D042683:Angiopoietin-1; D015703:Antigens, CD; D015820:Cadherins; D003598:Cytoskeletal Proteins; D007527:Isoenzymes; D010972:Platelet Activating Factor; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D015534:Trans-Activators; D042461:Vascular Endothelial Growth Factor A; D051176:beta Catenin; D000099152:Cadherin 5; C495270:CTNNB1 protein, human; C496628:PRKCA protein, human