Role of Caveolin-1 in the Maintenance of Blood-retinal Barrier Integrity

项目摘要 血视网膜屏障（BRB）选择性地和紧密地调节神经视网膜的局部环境。 BRB完整性的丧失是三种主要致盲原因的常见病理学：糖尿病视网膜病变;年龄- 相关性黄斑变性和早产儿视网膜病。最近的证据表明，小窝蛋白-1（Cav-1）是一种重要的蛋白质， 1），一个完整的蛋白质组成部分的专门脂质微域称为小窝，是必不可少的正常 视网膜功能Cav-1敲除小鼠显示Cav-1敲除小鼠的视网膜功能降低，如 视网膜电图（ERG）提示感光细胞缺陷。然而，这种减少的光感受器 功能不能解释为对光转导的直接影响，因为记录中的反应是正常的 从孤立的Cav 1零棒中分离出来这表明Cav-1缺失的视网膜中的功能缺陷是由Cav-1缺失引起的。 光感受器周围的异常局部环境。为了支持这一假设，令人信服的证据 表明Cav-1缺失小鼠具有高渗透性BRB。增加的渗透性与 紧密连接的改变、Na/K-ATP酶活性的变化和外视网膜水肿。Cav-1基因敲除小鼠 提供了令人信服的数据，显示视网膜色素上皮和血管屏障功能的明显丧失。这 增加的渗透性改变了正常的光感受器环境，这与降低的视网膜光感受器环境一致。 在这些小鼠中观察到的功能和年龄相关的视网膜变性。此外，当受到压力时， 范例（氧诱导的视网膜病变），Cav-1缺失小鼠显示严重的视网膜下和视网膜内 - -这些发现清楚地表明Cav-1的表达/功能对于维持细胞的增殖是必不可少的。 但这种调节的机制尚不清楚。第一个目标是确定 Cav-1在使用细胞特异性， 可诱导基因缺失第二个目标将测试Cav-1在脂质结构组织中的作用， 上皮细胞-细胞接触和顶突中的蛋白质。最后的目标将集中在失调的作用， 以及Cav-1如何调节ATP酶活性。

Project summary The blood-retinal barrier (BRB) selectively and tightly regulates the local environment of the neural retina. Loss of BRB integrity is a common pathology in three major causes of blindness: diabetic retinopathy; age- related macular degeneration; and retinopathy of prematurity. Recent evidence indicates that caveolin-1 (Cav- 1), an integral protein component of specialized lipid microdomains called caveolae, is essential for normal retinal function. Cav-1 null mice display reduced retinal function in Cav-1 null mice as indicated by electroretinography (ERG) that suggested at a photoreceptor defect. However, this reduced photoreceptor function could not be explained by a direct effect on phototransduction as responses were normal in recordings from isolated Cav-1 null rods. This suggests that the functional deficit in Cav-1 null retinas results from an abnormal local environment surrounding photoreceptors. In support of this hypothesis, compelling evidence indicates that Cav-1 null mice have a hyperpermeable BRB. The increased permeability correlates with alterations in tight junctions, changes in Na/K-ATPase activity, and outer retinal edema. Cav-1 null mice provide compelling data showing a clear loss of retinal pigment epithelial and vascular barrier functions. This increased permeability alters the normal photoreceptor environment which is consistent with reduced retinal function and age-related retinal degeneration observed in these mice. Furthermore, when subjected to a stress paradigm (oxygen-induced retinopathy), Cav-1 null mice display severe subretinal and intraretinal hemorrhaging. These findings clearly indicate that Cav-1 expression/function is essential for the maintenance of a robust BRB but the mechanism(s) of this regulation is unknown. The first aim is designed to determine the role of Cav-1 in regulating barrier activity specifically within the retinal pigment epithelium using cell-specific, inducible genetic deletion. The second aim will test the role of Cav-1 in the structural organization of lipids and proteins in epithelial cell-cell contacts and apical process. The final aim will focus on the role that dysregulation of the Na/K-ATPase plays and how Cav-1 regulates ATPase activity.