Li Jing, Ma Lan, Fan Ying, Zhang Yina, Sun Dianjun, Wu Bo
Pharmazie. 2016 Aug 1;71(8):465-471. doi: 10.1691/ph.2016.6586.
Parkinson's disease (PD) is a degenerative brain disorder characterized by motor symptoms and loss of dopaminergic (DA) neurons in the substantia nigra. The mechanisms for DA cell death in PD have been extensively investigated using PC12 cells treated with a dopamine neurotoxin 6-hydroxydopamine (6-OHDA). 6-OHDA may induce both autophagy and apoptosis in PC12 cells. However, it remains unclear whether crosstalk occurs between autophagy and apoptosis in PC12 cells treated with 6-OHDA and whether Raf-1/ERK1/2 and their phosphorylation status play a role in autophagy. In this study, we used MDC staining assay and flow cytometry and found that 6-OHDA induced autophagy in PC12 cells. This induction was inhibited by the autophagy inhibitor 3-MA. Our electron microscopy observations also supported 6-OHDA induced autophagy in PC12 cells. Apoptosis of PC12 cells was increased with inhibition of autophagy by 3-MA. In addition, Inhibition of Raf-1 resulted in a decreased 6-OHDA-induced autophagy rate among PC12 cells. Phosphorylation levels of Raf-1 and ERK1/2 were increased in PC12 cells treated with 6-OHDA and inhibited by co-treatment with 6-OHDA and 3-MA. These data suggest that crosstalk between 6-OHDA-induced apoptosis and autophagy in PC12 cells may be regulated via the Raf-1/ERK1/2 signaling pathway. Our data suggest a mechanism for 6-OHDA toxicity in PC12 cells, contributing to our understanding of the pathogenesis of PD.
帕金森病（PD）是一种退行性脑部疾病，其特征为运动症状以及黑质中多巴胺能（DA）神经元的丧失。使用经多巴胺神经毒素6-羟基多巴胺（6-OHDA）处理的PC12细胞，对PD中DA细胞死亡的机制进行了广泛研究。6-OHDA可能在PC12细胞中诱导自噬和凋亡。然而，在用6-OHDA处理的PC12细胞中，自噬和凋亡之间是否存在相互作用，以及Raf-1/ERK1/2及其磷酸化状态是否在自噬中发挥作用仍不清楚。在本研究中，我们使用MDC染色分析和流式细胞术，发现6-OHDA在PC12细胞中诱导自噬。这种诱导被自噬抑制剂3-MA抑制。我们的电子显微镜观察结果也支持6-OHDA在PC12细胞中诱导自噬。3-MA抑制自噬后，PC12细胞的凋亡增加。此外，抑制Raf-1导致6-OHDA诱导的PC12细胞自噬率降低。在用6-OHDA处理的PC12细胞中，Raf-1和ERK1/2的磷酸化水平升高，并被6-OHDA与3-MA共同处理所抑制。这些数据表明，6-OHDA诱导的PC12细胞凋亡和自噬之间的相互作用可能通过Raf-1/ERK1/2信号通路进行调节。我们的数据提示了6-OHDA对PC12细胞毒性的一种机制，有助于我们对PD发病机制的理解。
