Tajiri Naoki, Borlongan Cesar V, Kaneko Yuji
Center of Excellence for Aging & Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida Morsani College of Medicine, Tampa, FL, USA.
School of Physical Therapy & Rehabilitation Sciences, University of South Florida Morsani College of Medicine, Tampa, FL, USA.
CNS Neurosci Ther. 2016 Jul;22(7):602-10. doi: 10.1111/cns.12546. Epub 2016 Jun 1.
Hypoxic-ischemia alters mitochondrial membrane potential (Δψm), respiratory-related enzymes, and mitochondrial DNA (mtDNA). Drugs acting on mitochondria, such as cyclosporine A (CsA), may reveal novel mitochondria-based cell death signaling targets for stroke. Our previous studies showed that Parkinson's disease-associated protein DJ-1 participates in the acute endogenous neuroprotection after stroke via mitochondrial pathway. DJ-1 was detected immediately after stroke and efficiently translocated into the mitochondria offering a new venue for developing treatment strategies against stroke. Here, we examined a molecular interaction between CsA and mitochondrial integrity in the in vitro acute stroke model of oxygen glucose deprivation/reperfusion (OGD/R) injury with emphasis on DJ-1.
Primary rat neuronal cells (PRNCs) were exposed to OGD/R injury and processed for immunocytochemistry, ELISA, and mitochondria-based molecular assays to reveal the role of DJ-1 in CsA modulation of mitochondrial integrity.
Administration of CsA before stroke onset (24 h pre-OGD/R) afforded significantly much more robust neuroprotective effects than when CsA was initiated after stroke (2 h post-OGD/R), revealing that CsA exerted neuroprotection in the early phase of ischemic stroke. CsA prevented the mitochondria-dependent cell death signaling pathway involved in cytochrome c (Cyt c)-induced intrinsic apoptotic process. CsA preserved cellular ATP content, but not hexokinase activity under hypoxic conditions. CsA prevented both mtDNA decrement and Δψm degradation after reperfusion, and enhanced secretion of DJ-1 in the mitochondria, coupled with reduced oxidative stress.
These observations provided evidence that CsA maintained mitochondrial integrity likely via DJ-1 upregulation, supporting the concept that mitochondria-based treatments targeting the early phase of disease progression may prove beneficial in stroke.
缺氧缺血会改变线粒体膜电位（Δψm）、呼吸相关酶和线粒体DNA（mtDNA）。作用于线粒体的药物，如环孢素A（CsA），可能会揭示基于线粒体的中风细胞死亡信号新靶点。我们之前的研究表明，帕金森病相关蛋白DJ-1通过线粒体途径参与中风后的急性内源性神经保护。中风后立即检测到DJ-1，并有效地转运到线粒体中，为开发中风治疗策略提供了新途径。在此，我们研究了在氧糖剥夺/再灌注（OGD/R）损伤的体外急性中风模型中CsA与线粒体完整性之间的分子相互作用，重点关注DJ-1。
将原代大鼠神经元细胞（PRNCs）暴露于OGD/R损伤，并进行免疫细胞化学、ELISA和基于线粒体的分子检测，以揭示DJ-1在CsA调节线粒体完整性中的作用。
中风发作前（OGD/R前24小时）给予CsA比中风后（OGD/R后2小时）开始给予CsA具有显著更强的神经保护作用，这表明CsA在缺血性中风的早期发挥神经保护作用。CsA阻止了细胞色素c（Cyt c）诱导的内源性凋亡过程中涉及的线粒体依赖性细胞死亡信号通路。CsA在缺氧条件下保留了细胞ATP含量，但没有保留己糖激酶活性。CsA阻止了再灌注后mtDNA减少和Δψm降解，并增强了线粒体中DJ-1的分泌，同时降低了氧化应激。
这些观察结果提供了证据，表明CsA可能通过上调DJ-1来维持线粒体完整性，支持了针对疾病进展早期阶段的基于线粒体的治疗可能对中风有益的观点。
