IN VIVO ROLE OF CAVEOLIN-1 IN MODULATING PHOTORECEPTOR FUNCTION

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 血视网膜屏障丧失(BRB)是老年性黄斑变性(AMD)、糖尿病视网膜病变和早产儿视网膜病变的常见病理。我们实验室的证据表明，小窝蛋白-1(Cav-1)是一种称为小窝的特殊脂质微域的不可或缺的蛋白质成分，对正常的视网膜功能是必不可少的。我们观察到Cav-1基因缺失小鼠的视网膜功能下降，这是由视网膜电信号(ERG)提示的光感受器缺陷所致。然而，这种光感受器功能的降低不能用对光传导的直接影响来解释，因为在从分离的Cav-1零棒中记录的吸入电极反应是正常的。这导致我们提出，局部光感受器环境的改变导致了观察到的功能缺陷。为了支持这一假设，我们有数据表明，在Cav-1基因缺失的小鼠中，BRB的丢失和细胞外基质的显著变化。通透性的增加与紧密连接的改变有关，特别是闭塞的局部化。此外，当受到应激模式(氧诱导的视网膜病变)时，Cav-1基因缺失的小鼠表现出严重的视网膜出血，表明BRB完全崩溃。这些结果清楚地表明，Cav-1的表达对BRB的完整性是必不可少的。在RPE细胞中，小窝在顶端(非典型定位)和基底侧(典型定位)都显示出独特的双极定位，提示了RPE中小窝结构域潜在的新功能(S)。这个COBRE项目的目标是研究CAV-1调节RPE中BRB完整性的机制(S)。这些目标与计划的R01提交保持一致，它们的实现将为加强这一申请提供必要的数据。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Loss of the blood-retinal barrier (BRB) is a common pathology of age-related macular degeneration (AMD), diabetic retinopathy, and retinopathy of prematurity. Evidence from our laboratory indicates that caveolin-1 (Cav-1), an integral protein component of specialized lipid microdomains called caveolae, is essential for normal retinal function. We observed reduced retinal function in Cav-1 null mice as indicated by electroretinography (ERG) suggesting a photoreceptor defect. However, this reduced photoreceptor function cannot be explained by a direct effect on phototransduction as responses were normal in suction electrode recordings from isolated Cav-1 null rods. This has led us to propose that alterations in the local photoreceptor environment results in the observed functional deficit. In support of this hypothesis, we have data demonstrating loss of BRB in Cav-1 null mice and significant changes in the extracellular matrix. The increased permeability correlates with alterations in tight junctions and specifically, occludin localization. Furthermore, when subjected to a stress paradigm (oxygen-induced retinopathy), Cav-1 null mice displayed severe retinal hemorrhaging indicating complete BRB breakdown. These results clearly indicate that Cav-1 expression is essential for BRB integrity. In RPE cells, caveolae display a unique bipolar localization both apically (atypical localization) and basolaterally (typical localization) suggesting potential novel function(s) of caveolar domains in RPE. The goals of this COBRE project are to examine the mechanism(s) by which Cav-1 regulates BRB integrity in the RPE. These goals are aligned with a planned R01 submission and their accomplishment will provide essential data to strengthen this application.