Retinal degeneration and chloride channels

描述（由申请人提供）：人雌激素样蛋白-1（hBest 1）的突变与Best卵黄状黄斑营养不良（BVMD）、成人发病卵黄状黄斑营养不良（AVMD）和常染色体显性玻璃体视网膜脉络膜病变（ADVIRC）相关，但hBest 1的确切功能仍存在疑问，hBest 1功能障碍与疾病的联系机制尚不清楚。有强有力的证据表明，hBest 1是一个阴离子（Cl）通道。还有证据表明hBest 1调节电压门控Ca通道。该应用程序将测试hBest 1是一种多功能蛋白质的假设，它既是一个Cl通道，可能具有质膜和细胞内功能，也是其他离子通道（包括Ca通道）的调节剂。假设hBest 1的突变通过在视网膜色素上皮（RPE）水平上破坏视网膜中的离子转运而产生视网膜疾病。我们认为，跨视网膜色素上皮的离子运输中断导致光感受器和视网膜色素上皮之间的空间中的异常流体含量和组成。这损害了RPE和光感受器之间的相互作用，并有利于类维生素A衍生的色素的积累和卵黄状病变的发展。在这个应用中，我们将调查的功能和病理生理机制的hBest 1使用的分子，遗传和电生理方法与培养细胞转染hBest 1和hBest 1突变体，转基因小鼠与破坏或突变hBest 1基因，和新鲜分离和培养的视网膜色素上皮细胞。这些研究不仅将为卵黄状黄斑营养不良的机制提供重要的见解，而且还将阐明离子转运穿过视网膜色素上皮对正常视网膜稳态的作用。公共卫生相关性：这项研究涉及黄斑变性的机制，这是失明的主要原因之一。具体来说，我们将研究一种名为bestrophin的蛋白质功能障碍如何导致遗传性青少年发病形式的黄斑变性。我们期望这些研究将提供深入了解黄斑变性的机制和维持正常视网膜功能的机制。

DESCRIPTION (provided by applicant): Mutations in human bestrophin-1 (hBest1) are associated with Best vitelliform macular dystrophy (BVMD), adult-onset vitelliform macular dystrophy (AVMD), and autosomal dominant vitreoretinochoroidopathy (ADVIRC), but the precise function of hBest1 remains in doubt and the mechanisms linking hBest1 dysfunction with disease are unknown. There is strong evidence that hBest1 is an anion (Cl) channel. There is also evidence that hBest1 regulates voltage-gated Ca channels. This application will test the hypothesis that hBest1 is a multifunctional protein that is both a Cl channel, possibly with both plasma membrane and intracellular functions, and a regulator of other ion channels, including Ca channels. Mutations in hBest1 are hypothesized to produce retinal disease by disrupting ion transport in the retina at the level of the retinal pigment epithelium (RPE). We suggest that disruption of ion transport across the RPE results in abnormal fluid content and composition in the space between photoreceptors and RPE. This compromises the interaction between RPE and photoreceptors and favors accumulation of retinoid-derived pigments and development of vitelliform lesions. In this application, we will investigate the functions and pathophysiological mechanisms of hBest1 using a combination of molecular, genetic, and electrophysiological approaches with cultured cells transfected with hBest1 and hBest1 mutants, transgenic mice with disrupted or mutant hBest1 genes, and freshly-isolated and cultured retinal pigment epithelial cells. These studies will not only provide important insights into the mechanisms of vitelliform macular dystrophies, but will also shed light on the role of ion transport across the retinal pigment epithelium on normal retinal homeostasis. PUBLIC HEALTH RELEVANCE: This research addresses the mechanisms of macular degeneration, one of the major causes of blindness. Specifically, we will investigate how dysfunction of a protein called bestrophin causes an inherited juvenile-onset form of macular degeneration. We expect that these studies will provide insights into the mechanisms of macular degeneration and the mechanisms that maintain normal retinal function.