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.
Wang
Yihong
Y
BIDMC Genomic Center, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02115, USA. ywang3@bidmc.harvard.edu
Pampou
Sergey
S
Fujikawa
Koshi
K
Varticovski
Lyuba
L
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