Protein nitration in a mouse model of familial amyotrophic lateral sclerosis - Possible multifunctional role in the pathogenesis
Protein nitration in a mouse model of familial amyotrophic lateral sclerosis - Possible multifunctional role in the pathogenesis
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DOI：
10.1074/jbc.m413111200
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发表时间：
2005-04-22
影响因子：
4.8
通讯作者：
Bonetto, V
中科院分区：
文献类型：
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作者：
Casoni, F;Basso, M;Bonetto, V
已提出多种机制导致肌萎缩侧索硬化症 (ALS) 发病机制，包括氧化应激。氧化损伤作用的早期证据是基于在患者和小鼠模型中发现的高水平标记物，例如游离硝基酪氨酸 (NT)。然而，目前尚未有关于 ALS 硝化蛋白质靶点的全面研究报道。我们发现，与年龄匹配的对照组相比，家族性 ALS (FALS) 转基因小鼠模型在疾病症状前阶段的脊髓蛋白提取物中 NT 免疫反应性水平升高。 NT 免疫反应性在脊髓匀浆的可溶部分中增加，并在症状前 FALS 小鼠的运动神经元核周中发现点状染色。使用基于蛋白质组的策略，我们鉴定了在生理或病理条件下体内硝化的蛋白质，并比较了它们的特异性硝化水平。在出现症状前的 FALS 小鼠中，α 和 γ 烯醇酶、ATP 合成酶 β 链以及热休克同源 71-kDa 蛋白和肌动蛋白被过度硝化。我们通过基质辅助激光解吸/电离质谱法鉴定了体内氧化蛋白质中的 16 个硝化位点。特别是，α-烯醇酶在 Tyr(43) 处的硝化（也是磷酸化的目标）为硝化可能干扰磷酸化提供了更多证据。总之，我们认为蛋白质硝化可能在 ALS 发病机制中发挥作用，通过抑制特定蛋白质的功能直接发挥作用，并间接干扰蛋白质降解途径和磷酸化级联。
Multiple mechanisms have been proposed to contribute to amyotrophic lateral sclerosis (ALS) pathogenesis, including oxidative stress. Early evidence of a role for oxidative damage was based on the finding, in patients and murine models, of high levels of markers, such as free nitrotyrosine (NT). However, no comprehensive study on the protein targets of nitration in ALS has been reported. We found an increased level of NT immunoreactivity in spinal cord protein extracts of a transgenic mouse model of familial ALS (FALS) at a presymptomatic stage of the disease compared with age-matched controls. NT immunoreactivity is increased in the soluble fraction of spinal cord homogenates and is found as a punctate staining in motor neuron perikarya of presymptomatic FALS mice. Using a proteome-based strategy, we identified proteins nitrated in vivo, under physiological or pathological conditions, and compared their level of specific nitration. alpha- and gamma-enolase, ATP synthase beta chain, and heat shock cognate 71-kDa protein and actin were overnitrated in presymptomatic FALS mice. We identified by matrix-assisted laser desorption/ ionization mass spectrometry 16 sites of nitration in proteins oxidized in vivo. In particular, alpha-enolase nitration at Tyr(43), target also of phosphorylation, brings additional evidence on the possible interference of nitration with phosphorylation. In conclusion, we propose that protein nitration may have a role in ALS pathogenesis, acting directly by inhibiting the function of specific proteins and indirectly interfering with protein degradation pathways and phosphorylation cascades.