PEROXYNITRITE AND SOD IN MOTOR NEURON APOPTOSIS

描述(申请人摘要)：过氧亚硝酸盐是一种强大的氧化剂 在不同类型的细胞中启动细胞凋亡。申请人已证明 过亚硝酸根是由 超氧化物歧化和一氧化氮诱导培养的胚胎大鼠细胞凋亡 运动神经元失去萎缩的支持。两种一氧化氮的抑制剂 野生型铜/锌超氧化物歧化酶的合成及递送 细胞内脂质体对营养因子剥夺运动神经元的保护作用 来自于细胞凋亡。超氧化物歧化酶的突变与 肌萎缩侧索硬化症运动神经元选择性变性及超氧化物歧化酶突变体的表达 与肌萎缩侧索硬化症相关的诱导培养的神经细胞凋亡。申请人 此前曾提出，超氧化物歧化酶突变体的主要功能是 过氧亚硝酸根对酪氨酸硝化的催化作用。草皮罐头 过亚硝酸根催化酪氨酸和蛋白质硝化生成 3-硝基酪氨酸。硝化作用可以扰乱两种酪氨酸激酶信号 结构蛋白的转导和组装。酪氨酸硝化 发生于ALS和包括帕金森氏症在内的其他神经退行性疾病 疾病、多发性硬化症和阿尔茨海默氏症。常见的表型 到目前为止所研究的所有ALS/SOD突变中，有一种与 锌。缺锌的超氧化物歧化酶清除超氧化物歧化酶的效率较低 也是较好的酪氨酸硝化催化剂。在现在 申请者假设应激状态下的运动神经元 提高一氧化氮和超氧化物的生成率， 使这些神经元特别容易受到缺锌超氧化物歧化酶的影响。这个 申请人提议研究神经性一氧化氮的诱导 去营养支持培养的大鼠胚胎运动神经元中的合酶 并确定运动神经元中超氧化物的来源。vbl.使用 高效pH敏感脂质体输送特定金属含量的超氧化物歧化酶 对于运动神经元，申请者将研究缺锌超氧化物歧化酶的作用 在启动运动神经元凋亡以及一氧化氮是否 对ALS突变型超氧化物歧化酶的毒性是必要的。完成特定的 AIMS将有助于解释为什么运动神经元特别容易受到 肌萎缩侧索硬化症相关的超氧化物歧化酶突变。

DESCRIPTION (Applicant's Abstract): Peroxynitrite is a powerful oxidant that initiates apoptosis in diverse cell types. The applicant has shown that peroxynitrite produced by the diffusion-limited reaction between superoxide and nitric oxide induces apoptosis in cultured embryonic rat motor neuron deprived of atrophic support. Both inhibitors of nitric oxide synthesis and wild type Cu/Zn superoxide dismutase (SOD) delivered intracellularly with liposomes protect trophic factor deprived motor neurons from apoptosis. Mutations to superoxide dismutase are implicated in the selective degeneration of motor neurons in ALS and expression of SOD mutants associated with ALS induces neuronal apoptosis in cultures. The applicant has previously suggested that the main function of SOD mutants results from increased catalysis of tyrosine nitration by peroxynitrite. SOD can catalyze nitration of tyrosine and protein by peroxynitrite to form 3-nitrotyrosine. Nitration can disrupt both tyrosine kinase signal transduction and the assembly of structural proteins. Tyrosine nitration occurs in ALS and other neurodegenerative disorders including Parkinson's Disease, multiple sclerosis and Alzheimer's Disease. The common phenotype among all ALS/SOD mutations so far investigated is a decreased affinity for zinc. Zinc deficient SOD is both less efficient at scavenging superoxide and is also a better catalyst of tyrosine nitration. In the present application the applicant hypothesizes that motor neurons under stress increase the rates of both nitric oxide and superoxide production which makes these neurons particularly vulnerable to zinc-deficient SOD. The applicant proposes to investigate the induction of neuronal nitric oxide synthase in cultured rat embryonic motor neurons deprived of trophic support and characterize the sources of superoxide in motor neurons. Using efficient pH sensitive liposomes to deliver SOD with defined metal contents to motor neurons, the applicant will examine the role of zinc-deficient SOD in initiating apoptosis in motor neurons and whether nitric oxide is necessary for the toxicity of ALS mutant SOD. Completion of the specific aims will help explain why motor neurons are particularly vulnerable to mutations in SOD associated with ALS.