Peroxynitrite, nitrotyrosine and HSP90 in neuronal death

我们的长期目标是了解超氧化物歧化酶的突变如何增加氧化应激和 导致肌萎缩侧索硬化症(ALS)运动神经元死亡。我们已经证明了 超氧化物与亚硝酸根的扩散限制反应内源生成过亚硝酸根 一氧化氮诱导去营养支持培养的胚胎大鼠运动神经元的凋亡。 一氧化氮合成的抑制剂和铜锌超氧化物歧化酶(SOD)的释放 细胞内使用脂质体保护运动神经元免受细胞凋亡的影响。这些数据表明， 一氧化氮与超氧化物之间的相互作用在运动神经元凋亡中起一定作用。突变到 SOD参与了ALS运动神经元的选择性变性和ALS-1的表达。 转基因小鼠中的超氧化物歧化酶突变会导致运动神经元病。一种常见的表型 到目前为止研究的ALS-SOD突变是降低对锌的亲和力。我们已经证明了 缺锌的超氧化物歧化酶清除超氧化物歧化酶的效率较低，但对酪氨酸的催化作用较好 硝化作用。此外，缺锌超氧化物歧化酶中的铜可以作为非特异性的单电子。 氧化物酶，从抗氧化剂如抗坏血酸和谷胱甘肽中抢走电子，这些抗氧化剂可以转移 到氧气来产生超氧化物。在NO存在的情况下，缺锌的超氧化物歧化酶可以催化 过氧亚硝酸盐的形成。在之前的资金周期中，我们已经证明了缺锌的超氧化物歧化酶 通过一氧化氮依赖机制诱导运动神经元的凋亡。对于续订，我们的 第一个目标是进一步研究缺锌土壤可以杀死培养的细菌的机制。 并确定什么可以保护运动神经元免受这种毒性。我们的第二个目标 是描述营养因子在运动神经元中诱导的超氧化物的来源 戒烟。我们的第三个目标是测试过氧亚硝酸盐对酪氨酸的硝化作用在马达死亡中的作用。 营养因子剥夺或缺锌超氧化物歧化酶诱导的神经元。已完成的 特定的目标将为解释运动神经元是如何特别的 容易受到超氧化物歧化酶突变的影响，并在散发性和家族性肥胖症之间建立联系。

Our long-term goal is to understand how mutations to SOD can increase oxidative stress and cause the death of motor neurons in amyotrophic lateral sclerosis (ALS). We have shown that endogenous formation of peroxynitrite by the diffusion-limited reaction between superoxide and nitric oxide induces apoptosis in cultured embryonic rat motor neurons deprived of trophic support. Both inhibitors of nitric oxide synthesis as well as Cu.Zn superoxide dismutase (SOD) delivered intracellularly with liposomes protect motor neurons from apoptosis. These data indicate that the interaction between nitric oxide and superoxide has a role in motor neuron apoptosis. Mutations to SOD are implicated in the selective degeneration of motor neurons in ALS and expression of ALS- SOD mutants in transgenic mice produces motor neuron disease. A common phenotype among the ALS-SOD mutations so far investigated is to decrease the affinity for zinc. We have shown that zinc-deficient SOD is both less efficient at scavenging superoxide and a better catalyst of tyrosine nitration. Furthermore, the copper in zinc-deficient SOD can act as a non-specific one-electron oxidase, robbing electrons from antioxidants like ascorbate and glutathione that can be transferred to oxygen to produce superoxide. In the presence of NO, zinc-deficient SOD can catalyze the formation of peroxynitrite. In the previous cycle of funding, we have shown that zinc-deficient SOD induces apoptosis in motor neurons by a nitric oxide-dependent mechanism. For the renewal, our first aim is to further investigate the mechanisms by which zinc-deficient SODs can kill cultured motor neurons and to determine what can protect motor neurons from this toxicity. Our second aim is to characterize the source or sources of superoxide induced in motor neurons by trophic factor withdrawal. Our third aim is to test the role of tyrosine nitration by peroxynitrite in the death of motor neurons induced by either trophic factor deprivation or by zinc-deficient SOD. Completion of the specific aims will provide a mechanistic basis for explaining how motor neurons are particularly vulnerable to SOD mutations and establish a link between sporadic and familial SODs.