Takagi Hitoshi, Suzuma Kiyoshi, Otani Atsushi, Oh Hideyasu, Koyama Shinji, Ohashi Hirokazu, Watanabe Daisuke, Ojima Tomonari, Suganami Eri, Honda Yoshihito
Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Jpn J Ophthalmol. 2002 May-Jun;46(3):270-8. doi: 10.1016/s0021-5155(02)00482-3.
It has been reported that vitronectin receptor-type integrins mediate vascular cell proliferation and migration. In this study, we investigated the expression of vitronectin receptor-type integrins and osteopontin in ischemia-induced retinal neovascularization, and examined the role of osteopontin in angiogenesis as a ligand of vitronectin receptor-type integrins.
Retinal neovascularization was produced by exposing C57BL/6J mice to 75% oxygen from postnatal day (P) 7 to P12. Expression of vitronectin receptor-type integrins and osteopontin was assessed by Northern blot analysis, in situ hybridization, and immunofluorescence. The role of osteopontin in retinal angiogenesis was evaluated by tube formation assay using cultured bovine retinal microcapillary endothelial cells.
In the murine model, integrin alpha(v) mRNA was increased from P14 with a 2.6-fold peak response observed on P19, when retinal neovascularization was remarkable. Indirect immunofluorescence for vitronectin receptor-type integrins revealed prominent expression of integrin alpha(v)beta3/beta5 in the neovascular endothelial cells. Osteopontin mRNA was increased from P14, with a 2.0-fold peak response observed on P19. In situ hybridization demonstrated localization of osteopontin mRNA in neovascular tufts. Vascular endothelial growth factor-induced tube formation (8.3 +/- 0.6 mm/field) was inhibited significantly by treatment with anti-osteopontin antibody (4.8 +/- 0.7 mm/field, P <.001).
These data suggest that increased expression of both vitronectin receptor-type integrins and osteopontin in ischemic retina contribute to vascular endothelial cell proliferation and to retinal vascular formation by promoting interaction between endothelial cells and extracellular matrix, which leads to retinal neovascularization.
据报道，玻连蛋白受体型整合素介导血管细胞增殖和迁移。在本研究中，我们调查了玻连蛋白受体型整合素和骨桥蛋白在缺血诱导的视网膜新生血管形成中的表达，并研究了骨桥蛋白作为玻连蛋白受体型整合素的配体在血管生成中的作用。
通过将C57BL/6J小鼠从出生后第7天（P7）至第12天暴露于75%氧气中来诱导视网膜新生血管形成。采用Northern印迹分析、原位杂交和免疫荧光法评估玻连蛋白受体型整合素和骨桥蛋白的表达。使用培养的牛视网膜微血管内皮细胞通过管形成试验评估骨桥蛋白在视网膜血管生成中的作用。
在小鼠模型中，整合素α(v)mRNA从P14开始增加，在P19时观察到2.6倍的峰值反应，此时视网膜新生血管形成明显。玻连蛋白受体型整合素的间接免疫荧光显示整合素α(v)β3/β5在新生血管内皮细胞中显著表达。骨桥蛋白mRNA从P14开始增加，在P19时观察到2.0倍的峰值反应。原位杂交显示骨桥蛋白mRNA定位于新生血管丛中。血管内皮生长因子诱导的管形成（8.3±0.6mm/视野）在用抗骨桥蛋白抗体处理后显著受到抑制（4.8±0.7mm/视野，P<.001）。
这些数据表明，缺血视网膜中玻连蛋白受体型整合素和骨桥蛋白的表达增加，通过促进内皮细胞与细胞外基质之间的相互作用，有助于血管内皮细胞增殖和视网膜血管形成，从而导致视网膜新生血管形成。
