Disulphide-reduced superoxide dismutase-1 in CNS of transgenic amyotrophic lateral sclerosis models
Disulphide-reduced superoxide dismutase-1 in CNS of transgenic amyotrophic lateral sclerosis models
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DOI：
10.1093/brain/awh704
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发表时间：
2006-02-01
期刊：
影响因子：
14.5
通讯作者：
Marklund, SL
中科院分区：
文献类型：
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作者：
Jonsson, PA;Graffmo, KS;Marklund, SL
肌萎缩侧索硬化症（ALS）是一种神经退行性疾病折磨的随意运动系统。在普遍表达的酶超氧化物歧化酶-1（SOD 1）中，有100多种不同的突变与该疾病有关。为了寻找突变SOD 1的细胞毒性的性质，在多个转基因小鼠模型中检查了蛋白质的量、酶活性和结构特性以及CNS组织病理学。为了在小鼠的短寿命内产生ALS表型，似乎需要超过20倍的突变SOD 1合成速率增加。表达人野生型SOD 1或G93 A和D90 A突变蛋白的转基因小鼠的器官显示出高的稳态蛋白水平。这些SOD 1在CNS中的主要比例是无活性的，由于铜充电不足，所有含有亚组分与减少C57-C146 intrasubunit二硫键。G85 R和截短的G127 insTGGG突变体均表现出低的稳态蛋白水平，缺乏酶活性，并且没有C57-C146二硫键。相对于其他器官，这些突变体也富集在CNS中，这表明在易感组织中错误折叠的二硫化物还原的SOD 1的识别和降解效率低下。在终末期疾病中，尽管突变SOD 1 s的水平存在35倍的差异，但在脊髓中积累了类似数量的耐洗涤剂聚集体。小颗粒以及更大的更弥漫的人SOD 1（hSOD 1）-夹杂物开发的所有菌株，后者更明显的高hSOD 1水平。在hSOD 1水平高的菌株中观察到广泛的空泡化，但在hSOD 1水平低的菌株中没有观察到，这表明这些改变是与高hSOD 1水平相关的伪影，而不是与ALS引起的细胞毒性相关。研究结果表明，运动神经元变性可能是由于长期暴露于错误折叠的聚集倾向的二硫化物还原的SOD 1，这构成了稳定突变体的微小亚组分和不稳定突变体的较大比例。
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease afflicting the voluntary motor system. More than 100 different mutations in the ubiquitously expressed enzyme superoxide dismutase-1 (SOD1) have been associated with the disease. To search for the nature of the cytotoxicity of mutant SOD1s, amounts, enzymic activities and structural properties of the protein as well as the CNS histopathology were examined in multiple transgenic murine models. In order to generate the ALS phenotype within the short lifespan of the mouse, more than 20-fold increased rates of synthesis of mutant SOD1s appear to be required. The organs of transgenic mice expressing human wild-type SOD1 or either of the G93A and D90A mutant proteins showed high steady-state protein levels. The major proportion of these SOD1s in the CNS were inactive due to insufficient Cu charging and all contained subfractions with a reduced C57-C146 intrasubunit disulphide bond. Both G85R and the truncated G127insTGGG mutant showed low steady-state protein levels, lacked enzyme activity and had no C57-C146 disulphide bond. These mutants were also enriched in the CNS relative to other organs, suggesting inefficient recognition and degradation of misfolded disulphide-reduced SOD1 in susceptible tissues. In end-stage disease, despite 35-fold differences in levels of mutant SOD1s, similar amounts of detergent-resistant aggregates accumulated in the spinal cord. Small granular as well as larger more diffuse human SOD1 (hSOD1)-inclusions developed in all strains, the latter more pronounced in those with high hSOD1 levels. Widespread vacuolizations were seen in the strains with high levels of hSOD1 but not those with low, suggesting these alterations to be artefacts related to high hSOD1 levels and not to the ALS-causing cytotoxicity. The findings suggest that the motoneuron degeneration could be due to long-term exposure to misfolded aggregation-prone disulphide-reduced SOD1, which constitutes minute subfractions of the stable mutants and larger proportions of the unstable mutants.