Gap-Junction-Medicated Cell Death in Rod-Cone Dystrophie

视杆细胞营养不良中间隙连接介导的细胞死亡

• 批准号: 6725219
• 负责人: HARRIS RIPPS
• 金额: $ 15.59万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-02-01 至 2007-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6725219
• 关键词: HeLa cells; Xenopus oocyte; apoptosis; biological signal transduction; cone cell; electrophysiology; gap junctions; genetically modified animals; histology; immunocytochemistry; laboratory mouse; polymerase chain reaction; retinitis pigmentosa; rhodopsin; rod cell; transfection; visual photoreceptor

DESCRIPTION (provided by applicant): Retinitis pigmentosa (RP) constitutes a group of genetically-mediated, degenerative retinal diseases that display a broad range of phenotypes. There is appreciable heterogeneity in the pathologies that underlie the various forms of RP, but of the known cases, a substantial percentage arise as a consequence of mutations in rhodopsin or other rod-specific proteins. However, despite the fact that the genetic defect is expressed solely in the rod photoreceptors, otherwise healthy cone photoreceptors invariably die, resulting in severe visual impairment. The principal goal of this proposal is to test the hypothesis that the spread of the disease from dying rods to genetically normal cones is a form of "bystander" effect, mediated by the gap junctions that exist between these photoreceptor subtypes. On this view, agents that trigger the apoptotic process permeate the intercellular gap-junctional channels to carry proapoptotic signals from diseased rods to neighboring cones. If gap junctions are a significant factor in the non-cell-autonomous spread of photoreceptor degeneration, blocking transmission through these channels may provide a novel form of therapeutic intervention that would enable cones to be spared the fate of their neighbors. The experiments we plan to conduct will help to determine whether the cone photoreceptors of transgenic mice that express rod-specific gene defects exhibit a significantly higher survival when the gap-junctional protein (connexin36) that couples their rods and cones is disrupted. Cx36 "knockout" mice are available, and we propose to cross them with mice expressing various rod-specific mutations that result in rod-cone dystrophy. Cone structure and function will be assessed by a panel of histological, immunocytochemical, and electrophysiological methods. In addition, we plan to conduct a series of molecular biological and biochemical studies to examine further connexin expression in mammalian photoreceptors, and to identify proapoptotic agents that are able to permeate the intercellular channels.

描述（由申请人提供）：色素性视网膜炎（RP）是一组遗传介导的退行性视网膜疾病，表现出广泛的表型。各种形式的 RP 背后的病理学存在明显的异质性，但在已知病例中，很大一部分是视紫红质或其他视杆细胞特异性蛋白突变的结果。然而，尽管遗传缺陷仅在视杆细胞中表达，但健康的视锥细胞总是会死亡，从而导致严重的视力障碍。该提案的主要目标是检验以下假设：疾病从垂死的视杆细胞向遗传正常的视锥细胞的传播是一种“旁观者”效应，由这些光感受器亚型之间存在的间隙连接介导。根据这种观点，触发细胞凋亡过程的物质渗透到细胞间间隙连接通道，将促凋亡信号从患病的视杆细胞传递到邻近的视锥细胞。 如果间隙连接是光感受器变性非细胞自主传播的一个重要因素，那么阻断通过这些通道的传播可能会提供一种新的治疗干预形式，使视锥细胞免受其邻居的命运。 我们计划进行的实验将有助于确定，当连接视杆细胞和视锥细胞的间隙连接蛋白（connexin36）被破坏时，表达视杆细胞特异性基因缺陷的转基因小鼠的视锥细胞光感受器是否表现出显着更高的存活率。 Cx36“敲除”小鼠是可用的，我们建议将它们与表达各种视杆特异性突变的小鼠杂交，这些突变会导致视杆细胞营养不良。视锥细胞的结构和功能将通过一组组织学、免疫细胞化学和电生理学方法进行评估。此外，我们计划进行一系列分子生物学和生化研究，以进一步检查哺乳动物光感受器中的连接蛋白表达，并鉴定能够渗透细胞间通道的促凋亡剂。