ZINC DEFICIENT SOD AND NEUROFILAMENT DYSFUNCTION IN ALS

ALS 中缺锌的 SOD 和神经丝功能障碍

• 批准号: 2609707
• 负责人: JOHN P CROW
• 金额: $ 9.67万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-12-01 至 2001-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2609707
• 关键词: amyotrophic lateral sclerosis; chemical binding; copper; enzyme mechanism; metallothionein; mutant; neurofilament; nitric oxide; nitrites; nutrition related tag; superoxide dismutase; tissue /cell culture; zinc

DESCRIPTION: Familial amyotrophic lateral sclerosis (FALS) patients possessing any one of 35 known mutations to Cu,Zn superoxide dismutase (SOD) stand a >85% chance of developing this fatal neurodegenerative disease. These SOD mutants invariably cause motor neuron disease when expressed in transgenic mice despite the coexistence of the normal complement of wild-type SOD. The dominant effect of these mutants suggests a gained deleterious function rather than simple loss of superoxide dismutase activity. Evidence from this laboratory indicates that SOD mutants have decreased affinity for zinc in a rank order which appears to correlate with virulence. These observations are combined with the demonstration that zinc-deficient SOD catalyzes protein tyrosine nitration by peroxynitrite more efficiently than Zn-containing SOD. Furthermore, neurofilament-L, a protein critical to motor neuron survival, is a major target of SOD catalyzed nitration and binds zinc but not copper. Lastly, peroxynitrite treatment assembly of triplet neurofilament proteins in vitro, presumably by introducing a permanent negative charge on hydrophobic tyrosine. Thus, it is hypothesized that the selective motor neuron death characteristic of FALS results from the aberrant metal binding properties of SOD mutants which directly or indirectly lead to nitration of neurofilaments and subsequent inhibition of function.The following specific aims are proposed to characterize further metal binding-binding by SOD mutants under physiological relevant conditions, explore mechanisms by which metals may be lost from mutants in vivo, and elucidate mechanisms of peroxynitrite-induced neurofilament dysfunction. Specific Aim 1) Assess zinc and copper binding by SOD mutants, wild type, and zinc deficient forms under conditions of turnover and exposure to nitric oxide and peroxynitrite. Specific aim 2) Measure the zinc and copper binding properties of relevant proteins like neurofilaments and metallothioneins which bind metals in vitro and determine whether these proteins can alter the metal content of SODs by direct interaction or by acting as metal sinks. Specific aim 3) Determine the relative contribution of nitration of individual neurofilament proteins to inhibition of triplet neurofilament assembly in vitro and the extent of nitration required for inhibition.

描述：家族性肌萎缩性侧面硬化症（FALS）患者 拥有35个已知突变中的任何一个，锌超氧化物歧化酶（SOD） > 85％的可能发生这种致命的神经退行性疾病的机会。 这些SOD突变体在表达时总是引起运动神经元疾病 尽管正常补体共存，但转基因小鼠 野生型草皮。 这些突变体的主要作用表明获得了 有害功能，而不是简单的超氧化物歧化酶的损失 活动。 该实验室的证据表明SOD突变体具有 在等级顺序中对锌的亲和力下降，这似乎与 毒力。 这些观察结果与以下演示结合了 缺乏锌的SOD通过过氧亚硝酸盐催化蛋白酪氨酸硝酸盐 比含锌的SOD更有效。 此外，神经丝l，a 对运动神经元生存至关重要的蛋白质是SOD的主要靶标 催化硝化并结合锌，但不结合铜。 最后，过氧亚硝酸盐 在体外的三胞胎神经丝蛋白的治疗组件，大概是 引入疏水性酪氨酸的永久性负电荷。 因此，它 假设选择性运动神经元死亡的特征 来自SOD突变体的异常金属结合特性的结果 直接或间接导致神经丝的硝化和随后的硝化 抑制功能。提出以下特定目标 表征SOD突变体在下面的进一步的金属结合结合 生理相关条件，探索金属可能是的机制 因体内突变体而损失，并阐明过氧亚硝酸盐诱导的机制 神经丝功能障碍。 特定目的1）评估锌和铜结合 在SOD突变体，野生型和锌的情况下，在 营业额和暴露于一氧化氮和过氧亚硝酸盐中。 具体目标2） 测量相关蛋白的锌和铜结合特性 神经丝和金属霉素在体外结合金属并确定 这些蛋白是否可以直接改变草皮的金属含量 相互作用或用作金属水槽。 特定目标3）确定 单个神经丝蛋白硝化的相对贡献 在体外抑制三重神经丝组装的程度 抑制所需的硝化。