Progressive accumulation of α-synuclein is a key step in the pathological development of Parkinson’s disease. Impaired protein degradation and increased levels of α-synuclein may trigger a pathological aggregation in vitro and in vivo. The chaperone-mediated autophagy (CMA) pathway is involved in the intracellular degradation processes of α-synuclein. Dysfunction of the CMA pathway impairs α-synuclein degradation and causes cytotoxicity. In the present study, we investigated the effects on the CMA pathway and α-synuclein aggregation using bioactive ingredients (Dihydromyricetin (DHM) and Salvianolic acid B (Sal B)) extracted from natural medicinal plants. In both cell-free and cellular models of α-synuclein aggregation, after administration of DHM and Sal B, we observed significant inhibition of α-synuclein accumulation and aggregation. Cells were co-transfected with a C-terminal modified α-synuclein (SynT) and synphilin-1, and then treated with DHM (10 μM) and Sal B (50 μM) 16 hours after transfection; levels of α-synuclein aggregation decreased significantly (68% for DHM and 75% for Sal B). Concomitantly, we detected increased levels of LAMP-1 (a marker of lysosomal homeostasis) and LAMP-2A (a key marker of CMA). Immunofluorescence analyses showed increased colocalization between LAMP-1 and LAMP-2A with α-synuclein inclusions after treatment with DHM and Sal B. We also found increased levels of LAMP-1 and LAMP-2A both in vitro and in vivo, along with decreased levels of α-synuclein. Moreover, DHM and Sal B treatments exhibited anti-inflammatory activities, preventing astroglia- and microglia-mediated neuroinflammation in BAC-α-syn-GFP transgenic mice. Our data indicate that DHM and Sal B are effective in modulating α-synuclein accumulation and aggregate formation and augmenting activation of CMA, holding potential for the treatment of Parkinson’s disease.

中文翻译：

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二氢杨梅素和丹酚酸 B 抑制 α-突触核蛋白聚集并增强伴侣介导的自噬

α-突触核蛋白的逐渐积累是帕金森病病理发展的关键步骤。蛋白质降解受损和 α-突触核蛋白水平升高可能在体外和体内引发病理性聚集。伴侣介导的自噬 (CMA) 途径参与 α-突触核蛋白的细胞内降解过程。CMA 通路的功能障碍会损害 α-突触核蛋白降解并导致细胞毒性。在本研究中，我们使用从天然药用植物中提取的生物活性成分（二氢杨梅素 (DHM) 和丹酚酸 B (Sal B)）研究了对 CMA 途径和 α-突触核蛋白聚集的影响。在α-突触核蛋白聚集的无细胞和细胞模型中，在施用 DHM 和 Sal B 后，我们观察到对 α-突触核蛋白积累和聚集的显着抑制。细胞用 C 端修饰的 α-synuclein (SynT) 和 synphilin-1 共转染，然后在转染 16 小时后用 DHM (10 μM) 和 Sal B (50 μM) 处理；α-突触核蛋白聚集水平显着降低（DHM 为 68%，Sal B 为 75%）。同时，我们检测到 LAMP-1（溶酶体稳态标志物）和 LAMP-2A（CMA 的关键标志物）水平升高。免疫荧光分析显示，在用 DHM 和 Sal B 处理后，LAMP-1 和 LAMP-2A 与 α-突触核蛋白包涵体之间的共定位增加。我们还发现 LAMP-1 和 LAMP-2A 在体外和体内的水平增加，同时水平降低α-突触核蛋白。此外，DHM 和 Sal B 治疗表现出抗炎活性，可防止 BAC-α-syn-GFP 转基因小鼠中星形胶质细胞和小胶质细胞介导的神经炎症。