Mic60/mitofilin overexpression alters mitochondrial dynamics and attenuates vulnerability of dopaminergic cells to dopamine and rotenone.
Mic60/mitofilin overexpression alters mitochondrial dynamics and attenuates vulnerability of dopaminergic cells to dopamine and rotenone.
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DOI：
10.1016/j.nbd.2016.03.015
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发表时间：
2016-07
影响因子：
6.1
通讯作者：
Hastings TG
中科院分区：
文献类型：
--
作者：
Van Laar VS;Berman SB;Hastings TG
线粒体功能障碍与帕金森病（PD）神经病理学有关。Mic60，也被称为mitofilin，是线粒体内膜蛋白，是线粒体接触位点和嵴连接组织系统（MICOS）的关键组成部分。Mic60对于维持线粒体膜结构和功能至关重要。我们之前证明了线粒体Mic60蛋白在暴露于多巴胺醌后易受共价修饰和丰度损失的影响。在这项研究中，我们利用神经分化的SH-SY5Y和PC12多巴胺能细胞系来研究Mic60水平改变对线粒体功能和细胞对pd相关应激源的易感性的影响。短发卡RNA （shRNA）介导的神经元SH-SY5Y细胞内源性Mic60蛋白的敲低显著增强了多巴胺诱导的细胞死亡，通过共同表达shRNA不敏感的Mic60来挽救细胞死亡。相反，与对照相比，在PC12和SH-SY5Y细胞中，Mic60过表达显著减轻了多巴胺和鱼tenone诱导的细胞死亡。Mic60在SH-SY5Y细胞中的过表达也与线粒体呼吸增加有关，并且在鱼藤酮暴露后，备用呼吸能力增加。Mic60敲低细胞表现出呼吸抑制，并且在鱼藤酮治疗后，备用呼吸能力下降。Mic60过表达也影响线粒体裂变/融合动力学。过表达Mic60的PC12细胞表现出线粒体互联性增加。此外，PC12细胞和过表达Mic60的原代大鼠皮质神经元在神经突中均表现出线粒体裂变抑制和线粒体长度增加。这些结果表明，多巴胺能神经元细胞中Mic60水平的改变会显著影响线粒体稳态和细胞对PD相关应激源多巴胺和鱼tenone的易感性，从而影响PD的发病机制。
Mitochondrial dysfunction has been implicated in Parkinson’s disease (PD) neuropathology. Mic60, also known as mitofilin, is a protein of the inner mitochondrial membrane and a key component of the mitochondrial contact site and cristae junction organizing system (MICOS). Mic60 is critical for maintaining mitochondrial membrane structure and function. We previously demonstrated that mitochondrial Mic60 protein is susceptible to both covalent modification and loss in abundance following exposure to dopamine quinone. In this study, we utilized neuronally-differentiated SH-SY5Y and PC12 dopaminergic cell lines to examine the effects of altered Mic60 levels on mitochondrial function and cellular vulnerability in response to PD-relevant stressors. Short hairpin RNA (shRNA)-mediated knockdown of endogenous Mic60 protein in neuronal SH-SY5Y cells significantly potentiated dopamine-induced cell death, which was rescued by co-expressing shRNA-insensitive Mic60. Conversely, in PC12 and SH-SY5Y cells, Mic60 overexpression significantly attenuated both dopamine- and rotenone-induced cell death as compared to controls. Mic60 overexpression in SH-SY5Y cells was also associated with increased mitochondrial respiration, and, following rotenone exposure, increased spare respiratory capacity. Mic60 knockdown cells exhibited suppressed respiration and, following rotenone treatment, decreased spare respiratory capacity. Mic60 overexpression also affected mitochondrial fission/fusion dynamics. PC12 cells overexpressing Mic60 exhibited increased mitochondrial interconnectivity. Further, both PC12 cells and primary rat cortical neurons overexpressing Mic60 displayed suppressed mitochondrial fission and increased mitochondrial length in neurites. These results suggest that altering levels of Mic60 in dopaminergic neuronal cells significantly affects both mitochondrial homeostasis and cellular vulnerability to the PD-relevant stressors dopamine and rotenone, carrying implications for PD pathogenesis.