title: Attenuation of retinal vascular development and neovascularization in PECAM-1-deficient mice.
abstract: Platelet-endothelial cell adhesion molecule-1 (PECAM-1/CD31) is expressed on the surface of endothelial cells (EC) at high levels with important roles in angiogenesis and inflammation. However, the physiological role PECAM-1 plays during vascular development and angiogenesis remains largely unknown. Here we determined the role of PECAM-1 in the postnatal development of retinal vasculature and retinal neovascularization during oxygen-induced ischemic retinopathy (OIR) using PECAM-1-deficient (PECAM-1-/-) mice. A significant decrease in retinal vascular density was observed in PECAM-1-/- mice compared with PECAM-1+/+ mice. This was attributed to a decreased number of EC in the retinas of PECAM-1-/- mice. An increase in the rate of apoptosis was observed in retinal vessels of PECAM-1-/- mice, which was compensated, in part, by an increase in the rate of proliferation. However, the development and regression of hyaloid vasculature were not affected in the absence of PECAM-1. We did not observe a significant defect in astrocytes, the number of endothelial tip cell filopodias, and the rate of developing retinal vasculature progression in PECAM-1-/- mice. However, we observed aberrant organization of arterioles and venules, decreased secondary branching, and dilated vessels in retinal vasculature of PECAM-1-/- mice. In addition, retinal neovascularization was attenuated in PECAM-1-/- mice during OIR despite an expression of VEGF similar to that of PECAM-1+/+ mice. Mechanistically, these changes were associated with an increase in EphB4 and ephrin B2, and a decrease in eNOS, expression in retinal vasculature of PECAM-1-/- mice. These results suggest that PECAM-1 expression and its potential interactions with EphB4/ephrin B2 and eNOS are important for survival, migration, and functional organization of EC during retinal vascular development and angiogenesis.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792-4673, USA.
authors.forename: Terri A
authors.initials: TA
authors.lastname: Dimaio
authors.forename: Shoujian
authors.initials: S
authors.lastname: Wang
authors.forename: Qiong
authors.initials: Q
authors.lastname: Huang
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Scheef
authors.forename: Christine M
authors.initials: CM
authors.lastname: Sorenson
authors.forename: Nader
authors.initials: N
authors.lastname: Sheibani
mesh_terms: D000818:Animals; D017209:Apoptosis; D049109:Cell Proliferation; D024141:Collagen Type IV / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007511:Ischemia / Q000503:physiopathology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000473:pathology*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010100:Oxygen / Q000633:toxicity; D020286:Pericytes / Q000378:metabolism; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000235:genetics* / Q000378:metabolism; D036183:Receptor, EphB2 / Q000235:genetics / Q000378:metabolism; D036224:Receptor, EphB4 / Q000235:genetics / Q000378:metabolism; D012164:Retinal Diseases / Q000473:pathology; D012171:Retinal Vessels / Q000254:growth & development* / Q000473:pathology; D014357:Trypsin / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism
chemical_list: D024141:Collagen Type IV; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D042461:Vascular Endothelial Growth Factor A; D052250:Nitric Oxide Synthase Type III; C086681:Ephb4 protein, mouse; D036183:Receptor, EphB2; D036224:Receptor, EphB4; D014357:Trypsin; D010100:Oxygen