Mechanisms of SOD1 toxicity in ALS

SOD1 在 ALS 中的毒性机制

• 批准号: 7371657
• 负责人: JEFFREY L ELLIOTT
• 金额: $ 30.91万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7371657
• 关键词: Address; Amyotrophic Lateral Sclerosis; Applications Grants; Biochemistry; Copper; Disease; Familial Amyotrophic Lateral Sclerosis; Fractionation; Genes; Grant; Human; Immunoelectron Microscopy; In Vitro; Lead; Mitochondria; Molecular; Molecular Chaperones; Mus; Mutation; Neurologic; Pathology; Phenotype; Process; Spinal Cord; Toxic effect; Transgenic Mice; base; copper zinc superoxide dismutase; day; in vivo; insight; mutant; nervous system disorder

DESCRIPTION (provided by applicant): Although the factors that regulate SOD1 entrance, processing and aggregation within mitochondria are not fully understood, copper chaperone for SOD1 (CCS), appears to be an important determinant of SOD1 presence within mitochondria. In vitro evidence suggests that direct CCS interaction with SOD1 facilitates the conversion of immature apo-SOD1, that is capable of transit into mitochondria, to a mature holo-SOD1 form that is retained within mitochondria. Whether over-expressing CCS in vivo will alter the sub-cellular distribution of SOD1 in a way that favors intra-mitochondrial SOD1 retention and consequently impact mutant SOD1 induced disease is unknown. To address these key questions of SOD1 biochemistry in vivo, we have generated transgenic mice expressing human CCS in high levels within the CNS and crossed them to G93A-SOD1 or wild type (WT) SOD1 transgenic mice. Both CCS transgenic mice and CCS/WT-SOD1 dual transgenic mice are neurologically normal. In contrast, CCS/G93A-SOD1 dual transgenic mice develop accelerated neurological deficits, with a mean survival of 36 days compared to 242 days for G93A-SOD1 mice. Immuno-electron microscopy and sub-cellular fractionation studies on spinal cord show that G93A-SOD1 is enriched within mitochondria in the presence of CCS over-expression. Our results indicate that CCS over-expression in G93A-SOD1 mice produces severe mitochondrial pathology and accelerates disease course. The extent of these changes tells us that over-expressing CCS is changing a fundamental principle of G93A SOD1 induced neurological disease and raises two central questions. How is G93A SOD1 altered by CCS over-expression? How does this change in G93A SOD1 lead to the severe mitochondrial phenotype? Answering these two questions forms the basis for this grant proposal. Completion of the proposed aims in this grant will provide insights into the cellular and molecular mechanisms underlying one form of familial amyotrophic lateral sclerosis (ALS) related to mutations in the copper, zinc superoxide dismutase gene.

描述(申请人提供)：尽管调控线粒体内SOD1进入、加工和聚集的因素还不完全清楚，但SOD1的铜伴侣蛋白(CCS)似乎是线粒体内SOD1存在的一个重要决定因素。体外证据表明，CCS与SOD1的直接相互作用促进了未成熟的apo-SOD1转化为成熟的Holo-SOD1形式，并保留在线粒体中。在体内过表达CCS是否会改变SOD1的亚细胞分布，从而有利于线粒体内SOD1的保留，从而影响突变的SOD1诱导的疾病，目前尚不清楚。为了解决体内SOD1生物化学的这些关键问题，我们建立了在中枢神经系统内高水平表达人CCS的转基因小鼠，并将它们与G93A-SOD1或野生型(WT)SOD1转基因小鼠杂交。CCS转基因小鼠和CCS/WT-SOD1双转基因小鼠均为神经学正常小鼠。相比之下，CCS/G93A-SOD1双转基因小鼠出现加速的神经功能障碍，平均存活36天，而G93A-SOD1小鼠的平均存活时间为242天。免疫电子显微镜和亚细胞分级研究表明，在CCS过表达的情况下，G93A-SOD1在线粒体中丰富。我们的结果表明，CCS在G93A-SOD1小鼠中的过度表达会导致严重的线粒体病变，并加速疾病的进程。这些变化的程度告诉我们，过度表达CCS正在改变G93A SOD1诱导的神经疾病的基本原理，并提出了两个核心问题。CCS过表达如何改变G93A SOD1？G93A SOD1的这种改变是如何导致严重的线粒体表型的？回答这两个问题构成了这项赠款提案的基础。完成这笔赠款中的拟议目标将为深入了解一种形式的家族性肌萎缩侧索硬化症(ALS)与铜锌超氧化物歧化酶基因突变相关的细胞和分子机制提供见解。