ALS-mutant SOD1-induced motor neuron apoptosis

描述（由申请人提供）：肌萎缩性侧索硬化症（ALS）是 一种神经退化性疾病，特征是上下运动功能丧失 神经元，导致出现症状后1至6年死亡。 超氧化物歧化酶（SOD）的突变与2- 3%的病例有关 也是唯一被证实的致病原因我们发现这些 突变削弱了蛋白质的结构，这降低了对蛋白质的亲和力。 锌。野生型和突变型缺锌SOD均能诱导培养细胞凋亡 运动神经元通过需要一氧化氮的机制。然而，两种野生型 含铜和锌的突变SOD阻止运动神经元凋亡 由营养因子剥夺引起的。这些结果表明，突变SOD 蛋白质可以是功能性和保护性的，当它充满铜， 锌，但失去锌原子后变得有毒。我们假设 使SOD有毒的功能获得是由于锌的损失。我们进一步 假设野生型SOD可能在散发性ALS中变成锌缺乏 介导运动神经元变性。我们的结果是有争议的，因为他们 与在转基因小鼠中观察到的携带 ALS突变SOD。我们建议在纯化的运动神经元中测试我们的假设 来自过表达野生型人SOD的转基因小鼠以及小鼠 携带G93 A和G37 R ALS突变型SOD。我们还将测试硝酸的作用 氧化物在营养因子剥夺诱导运动神经元凋亡中的作用 和锌缺乏的SOD使用纯化的运动神经元从小鼠“敲除”， 神经元或内皮型一氧化氮合酶。的结果予以 调查将有助于解决一些争议的机制， ALS突变体SOD的毒性，并将提供新的见解，在机制的运动 ALS中的神经元变性可能导致新的 治疗策略

DESCRIPTION (provided by the Applicant): Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the loss of upper and lower motor neurons, which lead to death between 1 to 6 years after becoming symptomatic. Mutations in superoxide dismutase (SOD) are linked to 2-3 percent of the cases of ALS and are the only proven cause of the disease. We found that these mutations weaken the structure of the protein, which decreases the affinity for zinc. Both wild type and mutant zinc-deficient SOD induce apoptosis in cultured motor neurons by a mechanism requiring nitric oxide. However, both wild type and mutant copper and zinc-containing SOD prevent motor neuron apoptosis induced by trophic factor deprivation. These results suggest that mutant SOD protein can be functional and protective when it is replete with copper and zinc but becomes toxic after the zinc atom is lost. We hypothesize that the gain-of-function that makes SOD toxic is due to the loss of zinc. We further hypothesize that wild type SOD might become zinc-deficient in sporadic ALS mediating motor neuron degeneration. Our results are controversial since they are in apparent contradiction with observation in transgenic mice carrying ALS-mutant SOD. We propose to test our hypothesis in motor neurons purified from transgenic mice over expressing wild type human SOD as well as mice carrying the G93A and G37R ALS-mutant SOD. We also will test the role of nitric oxide in the induction of motor neuron apoptosis by trophic factor deprivation and Zn-deficient SOD by using motor neurons purified from mice "knockout" for neuronal or endothelial nitric oxide synthase. The results of these investigations will help to solve some controversy on the mechanism of ALS-mutant SOD toxicity and will provide new insight in the mechanism of motor neuron degeneration in ALS that could result in the development of new therapeutic strategies.