SOD1/Bcl-2 induced mitochondrial dysfunction in FALS and SALS.

SOD1/Bcl-2 诱导 FALS 和 SALS 线粒体功能障碍。

• 批准号: 8411141
• 负责人: PIERA PASINELLI
• 金额: $ 33.14万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-02 至 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8411141
• 关键词: Affect; Amyotrophic Lateral Sclerosis; Astrocytes; BCL2 gene; BH3 Domain; Binding; Cell Death; Cells; Cessation of life; Coculture Techniques; Complex; Data; Defect; Development; Diagnosis; Disease; Etiology; Exposure to; Family; Functional disorder; Gene Mutation; Genetic; Goals; Impairment; In Vitro; Knock-in Mouse; Link; Mediating; Metabolic; Microglia; Minority; Mitochondria; Morphology; Motor Neurons; Mus; Mutate; Nerve Degeneration; Neurodegenerative Disorders; Neuroglia; Onset of illness; Paralysed; Pathogenesis; Pathology; Pathway interactions; Patients; Peptides; Proteins; Reporting; Role; Scientist; Specificity; Spinal Cord; System; Testing; Therapeutic Effect; Toxic effect; Toxicant exposure; Transgenic Mice; Transgenic Organisms; Treatment Efficacy; Voltage-Dependent Anion Channel; base; design; immortalized cell; in vivo; lymphoblast; mitochondrial dysfunction; motor neuron degeneration; mouse model; mutant; novel; prevent; public health relevance; therapeutic target

DESCRIPTION (provided by applicant): Amyotrophic Lateral Sclerosis (ALS) is a devastating neurodegenerative disease of the motor neurons, which leads to paralysis and death within 3-5 years from diagnosis. ALS is mainly sporadic (SALS) without a known cause. Only a small fraction of ALS is familial (FALS). Thus, one of the biggest challenges in the study of the disease is how to reconcile disease mechanisms among the small percentage of familial cases and the vast majority of sporadic cases with no known etiology. It is crucial that we identify common pathogenic mechanisms between the two forms of the disease. Mitochondrial pathology is one of these common pathways, as mitochondria defects have been found in both SALS patients and transgenic mutant SOD1 (mutSOD1) mice model of ALS. Whether similar triggers in FALS and SALS damage the mitochondria is not known. Using mutSOD1 expressing cells and transgenic mice (to mimic FALS), as well as EVB immortalized lymphoblasts from SALS patients, we identified a potentially common trigger mechanism. In mutSOD1 mice, we showed that mutSOD1 aberrantly binds and forms a toxic complex with Bcl-2 in mitochondria. Upon this aberrant binding, mutSOD1 induces a conformational change in Bcl-2 that transforms it into a harmful protein by exposing the normally hidden toxic BH3 domain. Together, mutSOD1 and conformationally modified Bcl-2 impair mitochondrial viability, eventually inducing cell death. Interestingly, in a subset (~ 30%) of SALS patients with upper motor neuron onset, an oxidized form of wild type SOD1 aberrantly binds to Bcl-2, transforming Bcl- 2 into a toxic molecule through exposure of the BH3 domain, similarly to what we have reported for mutSOD1. With this competing renewal, we intend to focus on this common pathway of mitochondrial dysfunction shared by FALS-SOD1 and a subset of SALS patients. We will test in vivo the hypothesis that the conformational change in Bcl-2 leading to exposure of the toxic BH3 domain is an important mechanism in SOD1-induced mitochondrial dysfunction (AIM 1). We will then characterize the functional implications of the toxic complex between SOD1 and Bcl-2 by identifying key downstream mitochondrial target(s) (AIM 2) and determining the cellular specificity of the SOD1/Bcl-2-mediated mitochondrial dysfunction (AIM 3). Finally, we will test the beneficial effect of SOD1-like peptides that inhibit binding to Bcl-2 against SOD1-mediated cell death (AIM 4). The ultimate goal is to identify target-based therapies whose efficacy goes beyond the limited portion of familial cases.

描述（由申请人提供）：肌萎缩侧索硬化症（ALS）是一种破坏性的运动神经元神经退行性疾病，会导致诊断后 3-5 年内瘫痪和死亡。 ALS 主要为散发性 (SALS)，原因不明。只有一小部分 ALS 是家族性的 (FALS)。因此，该疾病研究的最大挑战之一是如何协调一小部分家族病例和绝大多数病因不明的散发病例之间的疾病机制。确定这两种疾病之间的共同致病机制至关重要。线粒体病理学是这些常见途径之一，因为在 SALS 患者和 ALS 转基因突变 SOD1 (mutSOD1) 小鼠模型中都发现了线粒体缺陷。 FALS 和 SALS 中的类似触发因素是否会损害线粒体尚不清楚。使用表达 mutSOD1 的细胞和转基因小鼠（模拟 FALS），以及来自 SALS 患者的 EVB 永生化淋巴母细胞，我们确定了一个潜在的常见触发机制。在 mutSOD1 小鼠中，我们发现 mutSOD1 与线粒体中的 Bcl-2 异常结合并形成有毒复合物。在这种异常结合后，mutSOD1 会诱导 Bcl-2 发生构象变化，通过暴露通常隐藏的有毒 BH3 结构域，将其转化为有害蛋白质。 mutSOD1 和构象修饰的 Bcl-2 共同损害线粒体活力，最终诱导细胞死亡。有趣的是，在上运动神经元发病的 SALS 患者亚群（约 30%）中，野生型 SOD1 的氧化形式异常地与 Bcl-2 结合，通过暴露 BH3 结构域将 Bcl-2 转化为有毒分子，与我们报道的 mutSOD1 类似。通过这种竞争性更新，我们打算重点关注 FALS-SOD1 和一部分 SALS 患者共有的线粒体功能障碍的常见途径。我们将在体内测试以下假设：Bcl-2 中的构象变化导致有毒的 BH3 结构域暴露，是 SOD1 诱导的线粒体功能障碍 (AIM 1) 的重要机制。然后，我们将通过识别关键下游线粒体靶标 (AIM 2) 并确定 SOD1/Bcl-2 介导的线粒体功能障碍 (AIM 3) 的细胞特异性，来表征 SOD1 和 Bcl-2 之间有毒复合物的功能影响。最后，我们将测试抑制与 Bcl-2 结合的 SOD1 样肽对 SOD1 介导的细胞死亡的有益作用 (AIM 4)。 最终目标是确定基于靶标的疗法，其疗效超出了有限的家族病例范围。