Modulation of Hypoxia-Induced Neovascularization by JSM6427, an Integrin α5β 1 Inhibiting Molecule

Abstract

Purpose: Integrin α 5β 1, a fibronectin receptor, is involved in endothelial cell migration and proliferation. Here we investigate the effect of JSM6427, an integrin α 5β 1 inhibiting molecule, on the development of retinal vascular system using the mouse model of oxygen-induced retinopathy (OIR). Methods: Endothelial cell migration and sprouting was analyzed in vitro using a 2D migration assay and a 3D sprouting/angiogenesis assay in fibrin gel. C57BL/C6 mice were exposed to 75% oxygen from postnatal day 7 (P7) to P12 and returned to room air thereafter. Intravitreal injection of 40 μ g JSM6427 was performed in each one eye on P14. On P17, vascular area, avascularized area, and neovascular blood vessel tufts were quantified after perfusion with fluorescein-coupled concanavalin A. The number of retinal neovascular cell nuclei was determined in hematoxylin-stained cross sections of the eyes. Integrin α 5 expression was determined by immunohistochemistry. Results: In vitro, JSM6427 inhibits the migration of HUVEC and the tube formation induced by both bFGF and VEGF. In vivo, integrin α 5 expression was detectable in neovascular retinal blood vessels. Oxygen treatment (positive control) in comparison with no oxygen treatment (negative control) reduced significantly the vascularized area and increased the avascularized area. A single intravitreal injection of 40 μ g JSM6427 resulted in a significant reduction of the vascularized area and the number of preretinal nuclei in comparison with the intravitreal injection of the vehicle while the avascularized area increased significantly. Conclusions: These results imply an essential role of integrin α 5β 1 in the refining of the retinal vasculature in OIR and suggest JSM6427 may have a possible therapeutic function for neovascular disease.

KEYWORDS:

• angiogenesis
• integrin α 5β 1
• integrin antagonists
• mouse model
• oxygen-induced retinopathy (OIR)