Retinal degeneration and chloride channels.

视网膜变性和氯离子通道。

• 批准号: 7097307
• 负责人: H. CRISS HARTZELL
• 金额: $ 29.69万
• 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 2008-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7097307
• 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）：在不放大的情况下读取此页面的能力取决于黄斑的完整性，黄斑的完整性，这是视网膜的一小部分，包括中央凹。黄斑变性是发达国家失明的主要原因。与年龄相关的黄斑变性（AMD）是黄斑的进行性变性，影响了65岁以上约20％的个体，但其原因仍然未知。推动该提议的假设是CI电流在视网膜色素上皮（RPE）中在散落的感光盘吞噬作用中起作用。在此过程中的缺陷会导致视网膜下空间中类视黄素和脂肪霉素色素的积累导致黄斑变性。我们建议CI通道在正常的吞噬作用中很重要，因为它们参与了在大量外部片段摄入细胞体积的调节。在RPE细胞中表达了包括CFTR，CIC-2，CIC-3和CIC-5在内的各种著名的CI通道，最近有人提出，一种引起最佳黄斑营养不良症的RPE蛋白是一种新的CI通道家族的创始成员。该项目的目的是表征在RPE细胞中表达并了解其功能的CI电流，尤其是Bestrophin介导的电流。有三个特定的目标。 （1）确定Bestrophin CI通道的特性。我们将通过斑块夹的异源表达的bestrophins分析来测试BestRophins是氯化物通道的亚基。 （2）表征RPE细胞中的氯化物通道。该目标检验了以下假设：几种类型的CI通道在功能上专门用于特定的RPE函数。该策略是使用全细胞和斑块夹记录来表征RPE细胞中的CI通道，并将其与包括BESTRophin在内的已知CI通道的性质进行比较。 （3）确定CI通道在光感受器椎间盘吞噬作用中的作用。该目标将检验以下假设：CI通道在RPE细胞对杆外段的吞噬作用中很重要。该假设将通过确定药理学抑制剂和反义敲低CI电流对RPE杆外段的吞噬作用的影响。