Retinal degeneration and chloride channels

视网膜变性和氯离子通道

基本信息

批准号：
8425046
负责人：
H. CRISS HARTZELL
金额：
$ 33.13万
依托单位：
EMORY UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-08-01 至 2015-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8425046
关键词：
Adult Affect Anions Blindness CLCA2 gene Categories Cell Line Cells Chloride Channels Chloride Ion Chlorides Clinical Pathology Conflict (Psychology)Coupled Data Defect Degenerative Disorder Disease susceptibility Etiology Eye Family Functional disorder Gene Mutation Genes Genetic Models Goals Homeostasis Human Image Inherited Ion Channel Knock-out Knowledge Light Measures Mental Health Modeling Molecular Monkeys Mus Mutation Pathway interactions Persons Physiological Physiology Play Primates Property Proteins RNA Splicing Regulation Research Retina Retinal Retinal Degeneration Retinal Diseases Role Signal Pathway Signal Transduction Structure of retinal pigment epithelium Testing Time Transgenic Mice Variant Vision Visual impairment Vitelliform macular dystrophy Work base basolateral membrane economic impact fetal inherited retinal degeneration inhibitor/antagonist innovation insight mouse model mutant mouse model patch clamp voltage

项目摘要

DESCRIPTION (provided by applicant): Retinal diseases affect an estimated 1 in 28 people in the US, and have a huge personal and economic impact. This application will investigate a rapidly-growing category of inherited retinal degenerations termed bestrophinopathies. Bestrophinopathies are caused by mutations in the human bestrophin-1 gene (hBest1). hBest1 mutations produce a panoply of both dominantly- and recessively-inherited retinal degenerations presenting a diverse range of clinical pathologies. It is well-established that hBest1 encodes a Ca-activated chloride channel (CaCC) that is expressed in the basolateral membrane of the retinal pigment epithelium (RPE) and that bestrophinopathies are characterized by a reduction in the electro-oculogram light peak that is generated by an RPE CaCC. These observations have led to the "CaCC hypothesis" for bestrophinopathies. Although considerable data supports the idea that bestrophinopathies are caused by defects in chloride transport by Best1, studies on knockout and knockin-mutant mouse models have provided strongly conflicting conclusions. The goal of this project is to examine in depth the CaCC hypothesis of bestrophinopathies. We will explore in detail the molecular mechanisms of the light peak to establish the ionic mechanisms underlying the light peak, from the Ca signals that initiate it to the anion channels that generate it. Our hypothesis is that the CRAC channel Orai-1 is responsible for the Ca influx that activates the Ca-activated anion channel Tmem16a/Ano1 to generate the light peak. We hypothesize that Best1 mutations reduce the light peak by two mechanisms: interacting with and regulating Ano1 activity and by altering Ca signaling. These studies will be accomplished using a combination of patch clamp recording and state-of-the-art Ca imaging of isolated RPE from wild type and transgenic mice and from monkey. These studies are innovative because they investigate fundamental properties of RPE cells that are poorly understood. Although it is clear that chloride channels are indispensible for normal RPE function, they remain inadequately investigated, both with regard to their regulation and their physiological roles in the retina. These studies are significant because understanding the ionic mechanisms of RPE function is essential to understanding retinal physiology and because it is becoming apparent that Best1 dysfunction plays a much larger role in retinopathies than previously recognized. In addition to being a prime player in causing bestrophinopathies, Best1 mutations may also contribute disease susceptibility or Best1 protein may be a downstream target in other retinopathies of unknown etiology.

描述（由申请人提供）：在美国，估计每 28 个人中就有 1 人患有视网膜疾病，并对个人和经济产生巨大影响。该应用将研究一种快速增长的遗传性视网膜变性，称为 bestropinopathies。 Bestropin 病是由人类 bestropin-1 基因 (hBest1) 突变引起的。 hBest1 突变产生一系列显性遗传性和隐性遗传性视网膜变性，呈现多种临床病理。众所周知，hBest1 编码 CaCC 激活的氯离子通道 (CaCC)，该通道在视网膜色素上皮 (RPE) 的基底外侧膜中表达，并且视黄斑病的特征是产生的眼电图光峰减少通过 RPE CaCC。这些观察结果得出了 bestropinopathies 的“CaCC 假说”。尽管大量数据支持 Bestropino 病是由 Best1 的氯离子转运缺陷引起的观点，但对敲除和敲入突变小鼠模型的研究却提供了强烈矛盾的结论。该项目的目标是深入研究 bestropinopathies 的 CaCC 假说。我们将详细探索光峰的分子机制，以建立光峰背后的离子机制，从启动光峰的 Ca 信号到生成光峰的阴离子通道。我们的假设是 CRAC 通道 Orai-1 负责 Ca2+ 流入，激活 Ca2+ 激活阴离子通道 Tmem16a/Ano1 以产生光峰。我们假设 Best1 突变通过两种机制减少光峰：与 Ano1 活性相互作用并调节 Ano1 活性以及改变 Ca 信号传导。这些研究将通过结合膜片钳记录和最先进的 Ca2+ 成像技术，对野生型、转基因小鼠和猴子的分离 RPE 进行成像来完成。这些研究具有创新性，因为它们研究了人们知之甚少的 RPE 细胞的基本特性。尽管很明显氯离子通道对于正常的 RPE 功能是不可或缺的，但在其调节及其在视网膜中的生理作用方面仍然没有得到充分的研究。这些研究意义重大，因为了解 RPE 功能的离子机制对于了解视网膜生理学至关重要，而且越来越明显的是，Best1 功能障碍在视网膜病变中发挥的作用比以前认识到的要大得多。除了是引起黄斑病的主要因素外，Best1 突变还可能导致疾病易感性，或者 Best1 蛋白可能是其他病因不明的视网膜病的下游靶点。