251. EphrinA1 Inhibits Vascular Endothelial Growth Factor-Induced Intracellular Signaling and Suppresses Retinal Neovascularization and Blood-Retinal Barrier Breakdown
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Hideyasu Oh, Masafumi Kurimoto, Daisuke Watanabe, Hitoshi Takagi, E. Suganami, Yoshihito Honda, Tomoaki Murakami, Nagahisa Yoshimura, Hirokazu Ohashi, Izumi Suzuma, Tomonari Ojima, and Kiyoshi Suzuma
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Vascular Endothelial Growth Factor A ,Blotting, Western ,Blood–retinal barrier ,Retinal Neovascularization ,Biology ,Permeability ,Article ,Pathology and Forensic Medicine ,Neovascularization ,Mice ,chemistry.chemical_compound ,Cell Movement ,Blood-Retinal Barrier ,In Situ Nick-End Labeling ,medicine ,Animals ,Immunoprecipitation ,Ephrin ,Cells, Cultured ,Protein Kinase C ,Mitogen-Activated Protein Kinase 1 ,Mitogen-Activated Protein Kinase 3 ,Erythropoietin-producing hepatocellular (Eph) receptor ,Endothelial Cells ,Ephrin-A2 ,Retinal Vessels ,Ephrin-A1 ,Blotting, Northern ,Immunohistochemistry ,Vascular Endothelial Growth Factor Receptor-2 ,Rats ,Cell biology ,Oncogene Protein v-akt ,Vascular endothelial growth factor B ,Vascular endothelial growth factor ,Vascular endothelial growth factor A ,medicine.anatomical_structure ,chemistry ,Vascular endothelial growth factor C ,Immunology ,Cattle ,medicine.symptom ,Signal Transduction - Abstract
The Eph receptor/ephrin system is a recently discovered regulator of vascular development during embryogenesis. Activation of EphA2, one of the Eph receptors, reportedly suppresses cell proliferation and adhesion in a wide range of cell types, including vascular endothelial cells. Vascular endothelial growth factor (VEGF) plays a primary role in both pathological angiogenesis and abnormal vascular leakage in diabetic retinopathy. In the study described herein, we demonstrated that EphA2 stimulation by ephrinA1 in cultured bovine retinal endothelial cells inhibits VEGF-induced VEGFR2 receptor phosphorylation and its downstream signaling cascades, including PKC (protein kinase C)-ERK (extracellular signal-regulated kinase) 1/2 and Akt. This inhibition resulted in the reduction of VEGF-induced angiogenic cell activity, including migration, tube formation, and cellular proliferation. These inhibitory effects were further confirmed in animal models. Intraocular injection of ephrinA1 suppressed ischemic retinal neovascularization in a dose-dependent manner in a mouse model. At a dose of 125 ng/eye, the inhibition was 36.0 ± 14.9% (P < 0.001). EphrinA1 also inhibited VEGF-induced retinal vascular permeability in a rat model by 46.0 ± 10.0% (P < 0.05). These findings suggest a novel therapeutic potential for EphA2/ephrinA1 in the treatment of neovascularization and vasopermeability abnormalities in diabetic retinopathy.
- Published
- 2006
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