CAS Key Laboratory of Receptor Research, Department of Neuropharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai, 201203, China; School of Pharmacy, University of Chinese Academy of Sciences, No.19A Yuquan road, Beijing, 100049, China.
Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai, 201203, China.
Pharmacol Res. 2019 Dec;150:104538. doi: 10.1016/j.phrs.2019.104538. Epub 2019 Nov 9.
The human A53T mutant of α-synuclein tends to aggregate and leads to neurotoxicity in familial Parkinson's disease (PD). The aggregation of α-synuclein is also found in sporadic PD. Thus, targeting α-synuclein clearance could be used as a drug-discovery strategy for PD treatment. Caffeic acid (CA) has shown neuroprotection in Alzheimer's disease or cerebral ischaemia; however, it is unclear whether CA confers neuroprotection in α-synuclein-induced PD models. Here we focus on whether and how A53T α-synuclein is affected by CA. We assessed the effect of CA on cell viability in SH-SY5Y cells overexpressing A53T α-synuclein. Pathway-related inhibitors were used to identify the autophagy mechanisms. Seven-month-old A53T α-synuclein transgenic mice (A53T Tg mice) received CA daily for eight consecutive weeks. Behaviour tests including the buried food pellet test, the pole test, the Rotarod test, open field analysis, and gait analysis were used to evaluate the neuroprotective effect of CA. Tyrosine hydroxylase and α-synuclein were assessed by immunohistochemistry or western blot in the substantia nigra (SN). We found that CA alleviated the cell damage induced by overexpressing A53T α-synuclein and that CA reduced A53T α-synuclein by activating the JNK/Bcl-2-mediated autophagy pathway. The efficacy of CA on A53T α-synuclein degradation was reversed by the autophagy inhibitor bafilomycin A1 and the JNK inhibitor SP600125. In A53T Tg mice, CA improved behavioural impairments, attenuated loss of dopaminergic neurons, enhanced autophagy and reduced α-synuclein in the SN. Thus, the results provide scientific evidence for the neuroprotective effect of CA in PD. Our work lays the foundation for CA clinical trials to treat PD in the future.
人源 A53T 突变的α-突触核蛋白在家族性帕金森病（PD）中易于聚集并导致神经毒性。α-突触核蛋白的聚集也存在于散发性 PD 中。因此，靶向α-突触核蛋白清除可能被用作 PD 治疗的药物发现策略。咖啡酸（CA）在阿尔茨海默病或脑缺血中显示出神经保护作用；然而，CA 是否在α-突触核蛋白诱导的 PD 模型中赋予神经保护作用尚不清楚。在这里，我们专注于 CA 是否以及如何影响 A53T α-突触核蛋白。我们评估了 CA 对过表达 A53T α-突触核蛋白的 SH-SY5Y 细胞活力的影响。使用途径相关抑制剂来鉴定自噬机制。接受 CA 治疗的 7 个月大 A53T α-突触核蛋白转基因小鼠（A53T Tg 小鼠）连续 8 周，每天 1 次。使用埋藏食物颗粒测试、棒测试、转棒测试、旷场分析和步态分析等行为测试来评估 CA 的神经保护作用。通过免疫组织化学或 Western blot 评估酪氨酸羟化酶和 α-突触核蛋白在黑质（SN）中的表达。我们发现 CA 减轻了过表达 A53T α-突触核蛋白引起的细胞损伤，CA 通过激活 JNK/Bcl-2 介导的自噬途径减少了 A53T α-突触核蛋白。自噬抑制剂巴弗洛霉素 A1 和 JNK 抑制剂 SP600125 逆转了 CA 对 A53T α-突触核蛋白降解的作用。在 A53T Tg 小鼠中，CA 改善了行为障碍，减轻了多巴胺能神经元的丧失，增强了自噬并减少了 SN 中的α-突触核蛋白。因此，这些结果为 CA 在 PD 中的神经保护作用提供了科学依据。我们的工作为未来 CA 临床试验治疗 PD 奠定了基础。
