Photoreceptor Cell Vulnerability and Glutathione Status

感光细胞脆弱性和谷胱甘肽状态

基本信息

批准号：
7642912
负责人：
BARRY S. WINKLER
金额：
$ 35.99万
依托单位：
OAKLAND UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-01 至 2011-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7642912
关键词：
Acetylcysteine Address Antibodies Antioxidants Biochemical Biological Assay Blindness Cattle Cause of Death Cavia Cell Survival Cells Cellular Stress Cessation of life Chemical Models Chemicals DNA Defense Mechanisms Detection Disulfides Drug Metabolic Detoxication Ensure Enzymes Face Free Radical Scavenging Generations Glucose Glutathione Glutathione Disulfide Goals Health Impairment Iodoacetates Ions Label Link Lipids Measurement Measures Membrane Metabolic Metabolic Pathway Metabolism Morphology Mus NADP Nature Outcome Oxidants Oxidation-Reduction Photoreceptors Pigment Epithelium Poison Post-Translational Protein Processing Predisposition Publications Rattus Reaction Reactive Oxygen Species Recycling Reduced Glutathione Reducing Agents Reporting Retina Retinal Retinal Cone Risk Rod Outer Segments S-ethyl glutathione Spermophilus Stress System Testing Therapeutic Time Toxin Vertebrate Photoreceptors Vision Work base chemical reaction design detoxication glucose metabolism improved metabolic poison mimetics oxidation oxidative damage photoreceptor cell outer segment photoreceptor degeneration receptor research study residence retinal neuron retinal rods sample fixation visual process visual processing

项目摘要

This proposal addresses critically important unresolved issues concerning the antioxidant capacities of vertebrate photoreceptor cells and inner retinal neurons. A common factor in the loss of photoreceptor cells appears to be reactive oxygen species generated in excess of that normally seen by these cells. The main goal of this proposal is to understand why photoreceptor cells are more vulnerable to metabolic or oxidative chemical stress than cells in the inner retinal layers. While it is commonly believed that reduced glutathione (GSH) is present in all retinal cells, several reports show that GSH is not immunologically detectable in rod and cone photoreceptor cells. However, GSH is clearly seen in inner retinal neurons and MOiler cells, and in the pigment epithelium. Our working hypothesis is that the exceptional vulnerability of photoreceptor cells to toxic chemicals is linked to a specific deficiency in GSH. The specific aims of this proposal test the following hypothesis: that a deficiency of photoreceptor cell GSH is responsible for the detrimental effects of toxic chemicals that cause the death of these cells, while the presence of GSH in inner retinal cells reduces their vulnerability to the same chemicals. We will evaluate this hypothesis by using whole rat retinas, serial sections of rat retinas, and bovine rod outer segments in electrophysiological and metabolic experiments designed to assess the linkage between photoreceptor cell viability and the GSH-redox cycle. Measurements will be made of glucose-dependent metabolism, NADPH generation, GSH content, antioxidant enzymes, morphology, and receptor potentials. We will also determine the extent to which N-acetylcysteine and glutathione ethyl ester, membrane permeant GSH-mimetics, protect photoreceptor cells exposed to a metabolic poison (iodoacetate) or an oxidizing chemical (ferrous ion). The two models of chemical stress that have been chosen for study each produce selective death of photoreceptor cells. Despite differences in the initiating damaging reactions for each stress, it is the guiding hypothesis of this proposal that the basis for the damage resides in a deficiency in GSH, and thus, a deficiency in the overall antioxidant and detoxication status of photoreceptor cells. The outcomes of the proposed work will improve our understanding of why photoreceptor cells are so vulnerable to oxidative and detrimental chemical reactions. These outcomes should help in the design of therapeutic treatments for photoreceptor degenerations that are linked to an inadequate antioxidative defense mechanism.

该提案解决了有关抗氧化剂的至关重要的未解决的问题脊椎动物感光细胞和视网膜内神经元的能力。光感受器细胞丧失的常见因素似乎是这些细胞通常所见的活性氧。该提案的主要目的是了解为什么光感受器细胞比内部视网膜内层中的细胞更容易受到代谢或氧化化学应激的影响。虽然通常认为所有视网膜细胞中都存在减少的谷胱甘肽（GSH），但几份报告表明，在杆和锥形感光细胞中，GSH在免疫学上无法检测到。然而，在内部视网膜神经元和Moiler细胞以及色素上皮中清楚地看到了GSH。我们的工作假设是，感光细胞对有毒化学物质的特殊脆弱性与特定的缺陷有关 GSH。该提案的具体目的检验了以下假设：感光细胞GSH缺乏导致导致这些细胞死亡的有毒化学物质的有害作用，而内部视网膜细胞中GSH的存在减少了它们对同一化学物质的脆弱性。我们将在电生理学和代谢实验中使用全大鼠视网膜，大鼠视网膜的串行切片以及牛杆外段评估这一假设，旨在评估光感受器细胞活力与GSH-REDOX循环之间的联系。测量将由葡萄糖依赖性代谢，NADPH产生，GSH含量，抗氧化剂，形态和受体电位组成。我们还将确定N-乙酰半胱氨酸和谷胱甘肽乙酯，膜渗透性GSH-MIMETICS，保护暴露于代谢毒物（碘乙酸）或氧化化学物质（纤毛离子）的光感受器细胞的程度。已选择用于研究的两个化学应激模型会导致感光细胞的选择性死亡。尽管每种压力的启动损害反应有所不同，但该提案的指导假设是损害的基础依赖于GSH的缺乏，因此，光感受器细胞的总体抗氧化剂和解毒状态的缺乏。拟议工作的结果将提高我们对为什么光感受器细胞如此容易受到氧化和有害化学反应的影响。这些结果应有助于设计与抗氧化防御机制不足有关的光感受器退化的治疗治疗方法。