Shishido Takeo, Nagano Yoshito, Araki Mutsuko, Kurashige Takashi, Obayashi Hitomi, Nakamura Takeshi, Takahashi Tetsuya, Matsumoto Masayasu, Maruyama Hirofumi
Department of Clinical Neuroscience and Therapeutics, Hiroshima University Graduate School of Biomedical and Health Sciences, 1-2-3 Minami-ku Kasumi, Hiroshima, 734-8551, Japan.
Department of Clinical Neuroscience and Therapeutics, Hiroshima University Graduate School of Biomedical and Health Sciences, 1-2-3 Minami-ku Kasumi, Hiroshima, 734-8551, Japan.
Neurosci Lett. 2019 Jan 18;690:145-150. doi: 10.1016/j.neulet.2018.10.020. Epub 2018 Oct 11.
Synphilin-1, a cytoplasmic protein, interacts with α-synuclein which is one of the main constituents of Lewy bodies and plays an important role in the pathology of Parkinson's disease (PD), in neurons. This interaction indicates that synphilin-1 may also play a central role in PD. However, the biological functions of synphilin-1 are not fully understood, and whether synphilin-1 is neurotoxic or neuroprotective remains controversial. This study examined the function of synphilin-1 in a PD model in vitro. We used an inhibitor of mitochondrial complex I, 1-methyl-4-phenylpyridinium (MPP). We established human neuroblastoma SH-SY5Y cell lines that stably expressed human synphilin-1. We found that overexpression of synphilin-1 increased SH-SY5Y cell viability after MPP treatment. We further found that synphilin-1 significantly suppressed apoptotic changes in nuclei, including nuclear condensation and fragmentation, after MPP treatment. We showed that synphilin-1 significantly decreased MPP-induced cleaved caspase-3 and cleaved poly-ADP-ribose polymerase levels by using western blotting. Production of reactive oxygen species (ROS) induced by MPP was significantly reduced in cells expressing synphilin-1 compared to those expressing empty vector. Synphilin-1 inhibited MPP-induced cytochrome c release from mitochondria into the cytosol. These data suggested that synphilin-1 may function to protect against dopaminergic cell death by preserving mitochondrial function and inhibiting early steps in the intrinsic apoptotic pathway. Taken together, our results indicated that synphilin-1 may play neuroprotective roles in PD pathogenesis by inhibiting ROS production and apoptosis.
α-突触核蛋白结合蛋白-1是一种胞质蛋白，在神经元中与α-突触核蛋白相互作用，α-突触核蛋白是路易小体的主要成分之一，在帕金森病（PD）的病理过程中起重要作用。这种相互作用表明α-突触核蛋白结合蛋白-1在PD中可能也起着核心作用。然而，α-突触核蛋白结合蛋白-1的生物学功能尚未完全明确，其是具有神经毒性还是神经保护作用仍存在争议。本研究在体外PD模型中检测了α-突触核蛋白结合蛋白-1的功能。我们使用了线粒体复合体I抑制剂1-甲基-4-苯基吡啶鎓（MPP）。我们建立了稳定表达人α-突触核蛋白结合蛋白-1的人神经母细胞瘤SH-SY5Y细胞系。我们发现，α-突触核蛋白结合蛋白-1的过表达提高了MPP处理后SH-SY5Y细胞的活力。我们进一步发现，α-突触核蛋白结合蛋白-1显著抑制了MPP处理后细胞核中的凋亡变化，包括核固缩和核碎裂。通过蛋白质免疫印迹法，我们发现α-突触核蛋白结合蛋白-1显著降低了MPP诱导的半胱天冬酶-3和聚ADP核糖聚合酶的裂解水平。与表达空载体的细胞相比，表达α-突触核蛋白结合蛋白-1的细胞中MPP诱导的活性氧（ROS）生成显著减少。α-突触核蛋白结合蛋白-1抑制了MPP诱导的细胞色素c从线粒体释放到细胞质中。这些数据表明，α-突触核蛋白结合蛋白-1可能通过维持线粒体功能和抑制内源性凋亡途径的早期步骤来发挥保护多巴胺能细胞死亡的作用。综上所述，我们的结果表明，α-突触核蛋白结合蛋白-1可能通过抑制ROS生成和细胞凋亡在PD发病机制中发挥神经保护作用。
