title: PKG-I inhibition attenuates vascular endothelial growth factor-stimulated angiogenesis.
abstract: Vascular endothelial growth factor (VEGF) stimulates nitric oxide (NO) production, which mediates many of its angiogenic actions. However, the angiogenic pathways that operate downstream of NO following VEGF treatment are not well characterized. Herein, we used DT-2 and DT-3, two highly selective cGMP-dependent protein kinase I peptide inhibitors to determine the contribution of PKG-I in VEGF-stimulated angiogenesis. Incubation of chicken chorioallantoic membranes (CAM) with PKG-I peptide inhibitors decreased vascular length in a dose-dependent manner, with DT-3 being more effective than DT-2. Moreover, inhibition of PKG-I with DT-3 abolished the angiogenic response elicited by VEGF in the rabbit eye cornea. PKG-I inhibition also blocked VEGF-stimulated vascular leakage. In vitro, treatment of cells with VEGF stimulated phosphorylation of the PKG substrate VASP through VEGFR2 activation; the VEGF-stimulated VASP phosphorylation was reduced by DT-2. Pre-treatment of cells with DT-2 or DT-3 inhibited VEGF-stimulated mitogen-activated protein kinase cascades (ERK1/2 and p38), growth, migration and sprouting of endothelial cells. The above observations taken together identify PKG-I as a downstream effector of VEGFR2 in EC and provide a rational basis for the use of PKG-I inhibitors in disease states characterized by excessive neovascularization.
authors.affiliation: Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, Patras, Greece.
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Koika
authors.forename: Zongmin
authors.initials: Z
authors.lastname: Zhou
authors.forename: Ioannis
authors.initials: I
authors.lastname: Vasileiadis
authors.forename: Charis
authors.initials: C
authors.lastname: Roussos
authors.forename: Federica
authors.initials: F
authors.lastname: Finetti
authors.forename: Martina
authors.initials: M
authors.lastname: Monti
authors.forename: Lucia
authors.initials: L
authors.lastname: Morbidelli
authors.forename: Andreas
authors.initials: A
authors.lastname: Papapetropoulos
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D049033:Chorioallantoic Membrane / Q000098:blood supply / Q000187:drug effects*; D003315:Cornea / Q000098:blood supply / Q000187:drug effects*; D017869:Cyclic GMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D005452:Fluoresceins / Q000494:pharmacology; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology; D010766:Phosphorylation; D011817:Rabbits; D015398:Signal Transduction; D042442:Vascular Endothelial Growth Factors / Q000494:pharmacology* / Q000502:physiology
chemical_list: C513505:DT-2 compound; C556898:DT-3 peptide; D005452:Fluoresceins; D010446:Peptide Fragments; D010455:Peptides; D042442:Vascular Endothelial Growth Factors; D009569:Nitric Oxide; D017869:Cyclic GMP-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases