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Molecular Mechanisms of Retinal cGMP-Activated Ion Channels

视网膜cGMP激活离子通道的分子机制

基本信息

批准号：
8204534
负责人：
MICHAEL D. VARNUM
金额：
$ 35.07万
依托单位：
WASHINGTON STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-02-04 至 2013-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8204534
关键词：
Address Apoptosis Area Binding Biochemical Blindness Brain Calcium Calmodulin Cell Death Cell Survival Cells Cessation of life Code Con-fer Cyclic GMP Data Defect Development Disease Event Functional disorder Genes Goals Health Homeostasis Human In Vitro Ion Channel Ion Channel Protein Knowledge Lead Link Macular degeneration Molecular Mutation Outcome Phosphatidylinositols Photoreceptors Phototransduction Predisposition Prevention approach Process Production Progress Reports Proteins Public Health Publishing Regulation Regulatory Pathway Research Research Design Research Methodology Resources Retinal Retinal Cone Retinal Degeneration Retinal Diseases Retinitis Pigmentosa Role Signal Transduction Testing Transgenes Transgenic Organisms Vision Vision Disorders Work Xenopus oocyte Zebrafish achromatopsia base cyclic-nucleotide gated ion channels disease-causing mutation endoplasmic reticulum stress gain of function mutation in vivo innovation insight mutant photoreceptor degeneration prevent retinal rods success trafficking visual information

项目摘要

PROJECT SUMMARY/ABSTRACT There is a fundamental gap in knowledge regarding how mutations in the genes encoding cyclic nucleotide- gated (CNG) ion channels can produce achromatopsia, cone dystrophy and macular degeneration in hu- mans. Our long-term objective is to understand the mechanisms controlling the activity of these channels and the pathophysiology of retinal diseases associated with CNG channel mutations. The core objectives of this application are to determine the cellular mechanisms responsible for the effect of cone CNG channel gating or trafficking mutations on cell viability, and the structural features critical for control of channels by phosphoinositides. Recently, we have functionally characterized several disease-associated mutations in the CNGA3 and CNGB3 subunits of cone CNG channels and discovered dramatic effects on channel gat- ing, regulation and/or trafficking, but the cellular consequences of these defects have not been determined. The central hypothesis is that gain-of-function mutations in cone CNG channels lead to photoreceptor death via enhanced or uncontrolled channel activity, disturbance of intracellular calcium (Ca2+) homeostasis and subsequent Ca2+-dependent apoptosis. Conversely, trafficking defects are expected to impair cell viability via endoplasmic reticulum (ER) stress. The rationale for the proposed research is that developing an under- standing of photoreceptor dysfunction and loss associated with abnormal CNG channel activity will provide insight into possible treatments for several related cone dystrophies. Guided by strong preliminary data, we will address these issues by pursuing two specific aims: (1) identify the connection between disease asso- ciated functional changes in cone CNG channels and the cellular mechanisms leading to photoreceptor dys- function and death; and (2) determine the mechanisms and interactions underlying the ability of CNGB3 subunits to confer sensitivity to channel control by phosphoinositides. These studies will utilize molecular and cellular manipulations, biochemical approaches and/or electrophysiological studies of human CNG channels expressed in cone photoreceptor derived 661W cells or Xenopus oocytes, and as transgenes in zebrafish cone photoreceptors. The proposed research is innovative in that informative in vitro studies will be extended to transgenic expression of mutant CNG channels in vivo. Overall, the proposed work is signif- icant because it is expected to enhance our understanding of the mechanisms that lead to retinal degenera- tion and blindness, and to provide insight into potential approaches for prevention of photoreceptor loss.

项目总结/摘要关于编码环核苷酸的基因中的突变是如何发生的，门控（CNG）离子通道可以在人的视网膜上产生色盲、视锥细胞营养不良和黄斑变性。人.我们的长期目标是了解控制这些通道活动的机制以及与CNG通道突变相关的视网膜疾病的病理生理学。的核心目标本申请旨在确定负责锥体CNG通道效应的细胞机制门控或运输突变对细胞活力的影响，以及对控制通道至关重要的结构特征，磷酸肌醇。最近，我们在功能上描述了几种疾病相关的突变， CNGA 3和CNGB 3亚基的锥体CNG通道，并发现显着影响通道门控，这些缺陷的细胞后果尚未确定。核心假设是锥细胞CNG通道的功能获得性突变导致光感受器死亡通过增强或不受控制的通道活性，干扰细胞内钙（Ca 2+）稳态，随后的Ca 2+依赖性凋亡。相反，运输缺陷预计会损害细胞活力通过内质网（ER）应激。拟议研究的基本原理是，开发一个下- 与异常CNG通道活性相关的光感受器功能障碍和损失的持续将提供深入了解几种相关视锥细胞营养不良的可能治疗方法。根据初步数据，我们将通过追求两个具体目标来解决这些问题：（1）确定疾病阿索 cone CNG通道的相关功能变化和导致光感受器功能障碍的细胞机制，功能和死亡;（2）确定CNGB 3能力的机制和相互作用亚基赋予对磷酸肌醇控制的通道的敏感性。这些研究将利用分子以及人CNG的细胞操作、生物化学方法和/或电生理学研究在视锥光感受器衍生的661 W细胞或爪蟾卵母细胞中表达的通道，以及作为转基因在斑马鱼视锥光感受器拟议的研究是创新的，因为信息丰富的体外研究将可以扩展到体内突变CNG通道的转基因表达。总的来说，这项工作意义重大，这是因为它有望增强我们对导致视网膜变性的机制的理解- 和失明，并提供深入了解潜在的方法，以防止感光细胞损失。