Stitt A W, McKenna D, Simpson D A, Gardiner T A, Harriott P, Archer D B, Nelson J
Department of Ophthalmology, The Queen's University of Belfast, United Kingdom.
Am J Pathol. 1998 May;152(5):1359-65.
Endothelial cell association with vascular basement membranes is complex and plays a critical role in regulation of cell adhesion and proliferation. The interaction between the membrane-associated 67-kd receptor (67LR) and the basement membrane protein laminin has been studied in several cell systems where it was shown to be crucial for adhesion and attachment during angiogenesis. As angiogenesis in the pathological setting of proliferative retinopathy is a major cause of blindness in the Western world we examined the expression of 67LR in a murine model of hyperoxia-induced retinopathy that exhibits retinal neovascularization. Mice exposed to hyperoxia for 5 days starting at postnatal day 7 (P7) and returned to room air (at P12) showed closure of the central retinal vasculature. In response to the ensuing retinal ischemia, there was consistent preretinal neovascularization starting around P17, which persisted until P21, after which the new vessels regressed. Immunohistochemistry was performed on these retinas using an antibody specific for 67LR. At P12, immunoreactivity for 67LR was absent in the retina, but by P17 it was observed in preretinal proliferating vessels and also within the adjacent intraretinal vasculature. Intraretinal 67LR immunoreactivity diminished beyond P17 until by P21 immunoreactivity was almost completely absent, although it persisted in the preretinal vasculature. Control P17 mice (not exposed to hyperoxia) failed to demonstrate any 67LR immunoreactivity in their retinas. Parallel in situ hybridization studies demonstrated 67LR gene expression in the retinal ganglion cells of control and hyperoxia-exposed mice. In addition, the neovascular intra- and preretinal vessels of hyperoxia-treated P17 and P21 mice labeled strongly for 67LR mRNA. This study has characterized 67LR immunolocalization and gene expression in a murine model of ischemic retinopathy. Results suggest that, although the 67LR gene is expressed at high levels in the retinal ganglion cells, the mature receptor protein is preferentially localized to the proliferating retinal vasculature and is almost completely absent from quiescent vessels. The differential expression of 67LR between proliferating and quiescent retinal vessels suggests that this laminin receptor is an important and novel target for future chemotherapeutic intervention during proliferative vasculopathies.
内皮细胞与血管基底膜的关联十分复杂，在调节细胞黏附和增殖过程中发挥着关键作用。膜相关67千道尔顿受体（67LR）与基底膜蛋白层粘连蛋白之间的相互作用已在多个细胞系统中得到研究，结果表明在血管生成过程中，这种相互作用对于黏附和附着至关重要。由于增生性视网膜病变病理情况下的血管生成是西方世界失明的主要原因，我们在一个表现出视网膜新生血管形成的高氧诱导视网膜病变小鼠模型中检测了67LR的表达。从出生后第7天（P7）开始暴露于高氧环境5天，然后在出生后第12天（P12）回到正常空气中的小鼠，其视网膜中央血管系统出现闭合。为应对随之而来的视网膜缺血，在大约P17时开始出现持续至P21的视网膜前新生血管形成，之后新生血管消退。使用针对67LR的特异性抗体对这些视网膜进行免疫组织化学检测。在P12时，视网膜中未检测到67LR的免疫反应性，但到P17时，在视网膜前增殖血管以及相邻的视网膜内血管系统中观察到了免疫反应性。视网膜内67LR免疫反应性在P17之后逐渐减弱，到P21时免疫反应性几乎完全消失，不过它在视网膜前血管系统中持续存在。对照P17小鼠（未暴露于高氧环境）的视网膜未显示出任何67LR免疫反应性。平行的原位杂交研究表明，对照小鼠和高氧暴露小鼠的视网膜神经节细胞中存在67LR基因表达。此外，高氧处理的P17和P21小鼠的视网膜内和视网膜前新生血管对67LR mRNA有强烈标记。本研究对缺血性视网膜病变小鼠模型中67LR的免疫定位和基因表达进行了表征。结果表明，尽管67LR基因在视网膜神经节细胞中高水平表达，但成熟的受体蛋白优先定位于增殖的视网膜血管系统，而在静止血管中几乎完全不存在。增殖性和静止性视网膜血管之间67LR的差异表达表明，这种层粘连蛋白受体是未来增生性血管病变化疗干预的一个重要且新颖的靶点。
