title: Eph B4 receptor signaling mediates endothelial cell migration and proliferation via the phosphatidylinositol 3-kinase pathway.
abstract: The goals of this study were 2-fold: 1) to determine whether stimulation of Eph B4 receptors promotes microvascular endothelial cell migration and/or proliferation, and 2) to elucidate signaling pathways involved in these responses. The human endothelial cells used possessed abundant Eph B4 receptors with no endogenous ephrin B2 expression. Stimulation of these receptors with ephrin B2/Fc chimera resulted in dose- and time-dependent phosphorylation of Akt. These responses were inhibited by LY294002 and ML-9, blockers of phosphatidylinositol 3-kinase (PI3K) and Akt, respectively. Eph B4 receptor activation increased proliferation by 38%, which was prevented by prior blockade with LY294002, ML-9, and inhibitors of protein kinase G (KT5823) and MEK (PD98059). Nitrite levels increased over 170% after Eph B4 stimulation, indicating increased nitric oxide production. Signaling of endothelial cell proliferation appears to be mediated by a PI3K/Akt/endothelial nitric-oxide synthase/protein kinase G/mitogen-activated protein kinase cascade. Stimulation with ephrin B2 also increased migration by 63% versus controls. This effect was inhibited by blockade with PP2 (Src inhibitor), LY294002 or ML-9 but was unaffected by the PKG and MEK blockers. Eph B4 receptor stimulation increased activation of both matrix metalloproteinase-2 and -9. The results from these studies indicate that Eph B4 stimulates migration and proliferation and may play a role in angiogenesis.
authors.affiliation: Cardiovascular Research Institute and Department of Medical Physiology, College of Medicine, the Texas A & M University System Health Science Center, Temple 76504, USA. jsteinle@tamu.edu
authors.forename: Jena J
authors.initials: JJ
authors.lastname: Steinle
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Meininger
authors.forename: Reza
authors.initials: R
authors.lastname: Forough
authors.forename: Guoyao
authors.initials: G
authors.lastname: Wu
authors.forename: Mack H
authors.initials: MH
authors.lastname: Wu
authors.forename: Harris J
authors.initials: HJ
authors.lastname: Granger
mesh_terms: D000470:Alkaloids / Q000494:pharmacology; D001381:Azepines / Q000494:pharmacology; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002227:Carbazoles; D002455:Cell Division; D002465:Cell Movement; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D007211:Indoles; D020935:MAP Kinase Signaling System; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008833:Microcirculation / Q000166:cytology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology; D009389:Neovascularization, Pathologic; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation; D011233:Precipitin Tests; D036224:Receptor, EphB4 / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors
chemical_list: D000470:Alkaloids; D001381:Azepines; D002227:Carbazoles; D002867:Chromones; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007211:Indoles; D009025:Morpholines; D009573:Nitrites; C056218:ML 9; C073601:KT 5823; D009569:Nitric Oxide; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D019869:Phosphatidylinositol 3-Kinases; D036224:Receptor, EphB4; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D002118:Calcium