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

描述（由申请人提供）：血-视网膜屏障（BRB）选择性且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中的常见病理：糖尿病视网膜病变;年龄相关性黄斑变性;和早产儿视网膜病变。最近的证据表明，小窝蛋白-1（Cav- 1）是称为小窝的专门脂质微结构域的组成蛋白，对正常视网膜功能至关重要。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）所示，这表明存在感光细胞缺陷。然而，这种降低的感光功能不能解释的光转导的直接影响，反应是正常的记录从孤立的Cav-1空杆。这表明Cav-1缺失视网膜的功能缺陷是由光感受器周围的异常局部环境引起的。为了支持这一假设，令人信服的证据表明，Cav-1基因敲除小鼠具有高渗透性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相关。Cav-1缺失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。这种增加的渗透性改变了正常的光感受器环境，这与在这些小鼠中观察到的视网膜功能降低和年龄相关的视网膜变性一致。此外，当经受应激范例（氧诱导的视网膜病变）时，Cav-1缺失小鼠显示出严重的视网膜下和视网膜内病变。这些发现清楚地表明，Cav-1的表达/功能是维持一个强大的BRB所必需的，但这种调节的机制是未知的。第一个目的是确定Cav-1在调节屏障活性中的作用，特别是在视网膜色素上皮细胞内使用细胞特异性的，可诱导的遗传缺失。第二个目标将测试Cav-1在上皮细胞-细胞接触和顶端过程中脂质和蛋白质的结构组织中的作用。最终的目标将集中在Na/K-ATP酶的失调所起的作用以及Cav-1如何调节ATP酶活性。 公共卫生相关性：血-视网膜屏障完整性的丧失是三种主要致盲原因中的常见病理：糖尿病视网膜病变;年龄相关性黄斑变性;和早产儿视网膜病变。该项目旨在研究调节血-视网膜屏障完整性的机制，以确定改善病理性血-视网膜屏障通透性的新的潜在治疗策略。

DESCRIPTION (provided by applicant): 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 micro-domains 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 hyper-permeable 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 sub-retinal and intra-retinal 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. PUBLIC HEALTH RELEVANCE: Loss of blood-retinal barrier integrity is a common pathology in three major causes of blindness: diabetic retinopathy; age-related macular degeneration; and retinopathy of prematurity. This project is designed to study mechanisms that regulate blood-retinal barrier integrity to define novel potential therapeutic strategies to ameliorate pathological blood-retinal barrier permeability.