Tissue- and Cell-Specific Mitochondrial Defect in Parkin-Deficient Mice
Tissue- and Cell-Specific Mitochondrial Defect in Parkin-Deficient Mice
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DOI：
10.1371/journal.pone.0099898
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发表时间：
2014-06-24
期刊：
影响因子：
3.7
通讯作者：
Lombes, Anne
中科院分区：
文献类型：
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作者：
Damiano, Maria;Gautier, Clement A.;Lombes, Anne
PARK 2基因编码的Parkin缺失是常染色体隐性遗传帕金森病的主要病因。在果蝇和哺乳动物细胞模型中，帕金已经被证明在维持线粒体质量所必需的各种过程中发挥作用，包括线粒体动力学，生物发生和降解。然而，线粒体质量控制机制的改变与体内神经元存活的相关性仍在争论中。我们使用综合线粒体评估来解决PARK 2（-/-）小鼠脑中的这个问题，包括通过极谱法或荧光法分析呼吸，通过分光光度测定法分析呼吸复合物活性，通过罗丹明123荧光法分析线粒体膜电位，通过真实的时间PCR分析线粒体DNA含量，以及通过总谷胱甘肽测量氧化应激，蛋白酶体活性，SOD 2表达与蛋白质氧化损伤PARK 2（-/-）脑中的呼吸速率降低，具有高分辨率，但不是标准呼吸测定法。这种缺陷是纹状体特有的，在神经元中很突出，但在星形胶质细胞中不太严重。它存在于原代胚胎细胞中，并且在9至24月龄的体内没有恶化。它与任何呼吸复合体缺陷无关，包括复合体I。PARK 2（-/-）小鼠的线粒体内膜电位与野生型小鼠相似，但随着纹状体衰老，对解偶联的敏感性增加。线粒体谷胱甘肽含量和氧化加合物的增加，但正常的蛋白酶体活性显示出有效的补偿，在纹状体中的氧化应激的存在。SOD 2表达仅在24月龄的PARK 2（-/-）小鼠的纹状体中增加。总之，我们的研究结果表明，PARK 2（-/-）小鼠生命早期存在组织特异性线粒体缺陷，轻度影响呼吸，对线粒体膜电位没有显著影响，其潜在机制仍有待阐明，因为复合物I缺陷和显著的氧化损伤被排除在外。
Loss of Parkin, encoded by PARK2 gene, is a major cause of autosomal recessive Parkinson's disease. In Drosophila and mammalian cell models Parkin has been shown in to play a role in various processes essential to maintenance of mitochondrial quality, including mitochondrial dynamics, biogenesis and degradation. However, the relevance of altered mitochondrial quality control mechanisms to neuronal survival in vivo is still under debate. We addressed this issue in the brain of PARK2(-/-) mice using an integrated mitochondrial evaluation, including analysis of respiration by polarography or by fluorescence, respiratory complexes activity by spectrophotometric assays, mitochondrial membrane potential by rhodamine 123 fluorescence, mitochondrial DNA content by real time PCR, and oxidative stress by total glutathione measurement, proteasome activity, SOD2 expression and proteins oxidative damage. Respiration rates were lowered in PARK2(-/-) brain with high resolution but not standard respirometry. This defect was specific to the striatum, where it was prominent in neurons but less severe in astrocytes. It was present in primary embryonic cells and did not worsen in vivo from 9 to 24 months of age. It was not associated with any respiratory complex defect, including complex I. Mitochondrial inner membrane potential in PARK2(-/-) mice was similar to that of wild-type mice but showed increased sensitivity to uncoupling with ageing in striatum. The presence of oxidative stress was suggested in the striatum by increased mitochondrial glutathione content and oxidative adducts but normal proteasome activity showed efficient compensation. SOD2 expression was increased only in the striatum of PARK2(-/-) mice at 24 months of age. Altogether our results show a tissue-specific mitochondrial defect, present early in life of PARK2(-/-) mice, mildly affecting respiration, without prominent impact on mitochondrial membrane potential, whose underlying mechanisms remain to be elucidated, as complex I defect and prominent oxidative damage were ruled out.