title: PLD1-dependent PKCgamma activation downstream to Src is essential for the development of pathologic retinal neovascularization.
abstract: Vascular endothelial growth factor (VEGF) appears to be an important mediator of pathologic retinal angiogenesis. In understanding the mechanisms of pathologic retinal neovascularization, we found that VEGF activates PLD1 in human retinal microvascular endothelial cells, and this event is dependent on Src. In addition, VEGF activates protein kinase C-gamma (PKCgamma) via Src-dependent PLD1 stimulation. Inhibition of Src, PLD1, or PKCgamma via pharmacologic, dominant negative mutant, or siRNA approaches significantly attenuated VEGF-induced human retinal microvascular endothelial cell migration, proliferation, and tube formation. Hypoxia also induced Src-PLD1-PKCgamma signaling in retina, leading to retinal neovascularization. Furthermore, siRNA-mediated down-regulation of VEGF inhibited hypoxia-induced Src-PLD1-PKCgamma activation and neovascularization. Blockade of Src-PLD1-PKCgamma signaling via the siRNA approach also suppressed hypoxia-induced retinal neovascularization. Thus, these observations demonstrate, for the first time, that Src-dependent PLD1-PKCgamma activation plays an important role in pathologic retinal angiogenesis.
authors.affiliation: Departments of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
authors.forename: Qiuhua
authors.initials: Q
authors.lastname: Zhang
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Venkatesh
authors.initials: V
authors.lastname: Kundumani-Sridharan
authors.forename: Laxmisilpa
authors.initials: L
authors.lastname: Gadiparthi
authors.forename: Dianna A
authors.initials: DA
authors.lastname: Johnson
authors.forename: Gabor J
authors.initials: GJ
authors.lastname: Tigyi
authors.forename: Gadiparthi N
authors.initials: GN
authors.lastname: Rao
mesh_terms: D015153:Blotting, Western; D002448:Cell Adhesion; D002465:Cell Movement; D049109:Cell Proliferation; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006801:Humans; D010739:Phospholipase D / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism*; D012160:Retina / Q000378:metabolism* / Q000473:pathology; D015861:Retinal Neovascularization; D015398:Signal Transduction; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C087857:protein kinase C gamma; D016392:Proto-Oncogene Proteins pp60(c-src); D011493:Protein Kinase C; D010739:Phospholipase D; C106801:phospholipase D1