Retinal degeneration and chloride channels.

视网膜变性和氯离子通道。

• 批准号: 6927865
• 负责人: H. CRISS HARTZELL
• 金额: $ 30.4万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6927865
• 关键词: Xenopus; antisense nucleic acid; biophysics; calcium; calmodulin; cell morphology; cellular polarity; chloride channels; eye pharmacology; human tissue; ion transport; ligands; macular degeneration; membrane permeability; phagocytosis; phosphorylation; polymerase chain reaction; protein quantitation /detection; protein structure function; retinal pigment epithelium; rod cell; site directed mutagenesis; tamoxifen; transfection; voltage /patch clamp

DESCRIPTION (provided by applicant): The ability to read this page without magnification depends upon the integrity of the macula, a small region of the retina including the fovea. Macular degeneration is the leading cause of blindness in developed countries. Age-related macular degeneration (AMD) is a progressive degeneration of the macula that affects approximately 20% of individuals over the age of 65, but its causes remain unknown. The hypothesis driving this proposal is that CI currents play a role in phagocytosis of shed photoreceptor discs by the retinal pigment epithelium (RPE). Defects in this process can lead to macular degeneration as the result of accumulation of retinoids and lipofuscin pigment in the subretinal space. We propose that CI channels are important in normal phagocytosis because they are involved in the regulation of cell volume during ingestion of large quantities of outer segments. A variety of well-known CI channels including CFTR, CIC-2, CIC-3, and CIC-5 are expressed in RPE cells and recently it has been suggested that bestrophin, an RPE protein that causes Best macular dystrophy, is the founding member of a new family of CI channels. The goal of this project is to characterize the CI currents, especially bestrophin-mediated currents, that are expressed in RPE cells and to understand their function. There are three specific aims. (1) To determine the properties of bestrophin CI channels. We will test the hypothesis that bestrophins are subunits of a chloride channel by patch clamp analysis of heterologously expressed bestrophins. (2) To characterize chloride channels in RPE cells. This aim tests the hypothesis that several types of CI channels are functionally specialized for specific RPE functions. The strategy is to use whole-cell and patch clamp recording to characterize CI channels in RPE cells and to compare them to the properties of known CI channels, including bestrophin. (3) To determine the role of CI channels in photoreceptor disc phagocytosis. This aim will test the hypothesis that CI channels are important in phagocytosis of rod outer segments by RPE cells. This hypothesis will be tested by determining the effects of pharmacological inhibitors and antisense knockdown of CI currents on the phagocytosis of rod outer segments by RPE.

描述（由申请人提供）：在没有放大的情况下阅读本页的能力取决于黄斑的完整性，黄斑是视网膜的一个小区域，包括中央凹。黄斑变性是发达国家失明的主要原因。视网膜相关性黄斑变性（AMD）是黄斑的进行性变性，其影响约20%的65岁以上的个体，但其原因仍然未知。驱动该提议的假设是CI电流在视网膜色素上皮（RPE）对脱落的感光盘的吞噬中起作用。这个过程中的缺陷可导致黄斑变性，这是由于类维生素A和脂褐素色素在视网膜下腔中积累的结果。我们认为CI通道在正常的吞噬作用中是重要的，因为它们参与了大量外节摄取过程中细胞体积的调节。包括CFTR、CIC-2、CIC-3和CIC-5在内的多种众所周知的CI通道在RPE细胞中表达，并且最近已经提出，斑萎蛋白（bestrophin）（一种导致Best黄斑营养不良的RPE蛋白）是CI通道的新家族的创始成员。本项目的目标是表征在RPE细胞中表达的CI电流，特别是bestrophin介导的电流，并了解其功能。有三个具体目标。(1)确定斑萎蛋白CI通道的性质。我们将通过对异源表达的雌激素的膜片钳分析来检验雌激素是氯离子通道亚基的假设。(2)表征RPE细胞中的氯离子通道。这一目的测试了几种类型的CI通道在功能上专门用于特定RPE功能的假设。该策略是使用全细胞和膜片钳记录来表征RPE细胞中的Cl通道，并将其与已知Cl通道（包括雌激素）的性质进行比较。(3)确定CI通道在感光盘吞噬作用中的作用。该目的将检验Cl通道在RPE细胞吞噬视杆外节中是重要的假设。将通过确定药理学抑制剂和CI电流的反义敲低对RPE对视杆外节的吞噬作用的影响来检验该假设。