VPS35调节α-突触核蛋白外泌体分泌的相关机制研究

The pathogenesis of Parkinson's disease (PD) remains unclear, and more evidences suggested that the exosomal secretion of α-synuclein plays an important role in the disease occurrence and development. Our previous study indicated that VPS35, an important part of retromer complex, its mutation could increase the exosomal secretion of α-synuclein, which induced the transmission of α-synuclein among adjacent neurons, followed by the damage of neurons. To further understand the mechanism of VPS35 modulating exosomal secretion of α-synuclein, we will utilize quantative proteomic approaches to screen endosome associated transportation proteins and further indentify the role of the target protein on exosomal secretion of α-synuclein.The proposal will not only help us to understand how VPS35 modulating the exosomal secretion of α-synuclein and the transmission of exosomal α-synuclein among adjacent different neurons, also provide a new valuable clue to the pathogenesis and intervention therapy of Parkinson's disease.

帕金森病（PD）病因和进展机制尚不明确，许多证据表明细胞外α-突触核蛋白（α-synuclein）、特别是外泌体型α-synuclein在PD发生和发展过程中起重要作用，申请者前期研究发现VPS35作为逆运复合体的重要组成部分，其基因突变后增加细胞内α-synuclein的外泌体分泌，可导致更多胞外α-synuclein在邻近多巴胺能（DA）神经元间播散并产生损伤作用。为探讨其中具体机制，申请者将应用相互作用蛋白质组学方法找出参与VPS35调节细胞内α-synuclein外泌体分泌的目标内体转运相关蛋白，并验证该目标蛋白在VPS35调节细胞内α-synuclein外泌体分泌途径中的作用。明确VPS35、内体转运相关蛋白和α-synuclein外泌体分泌三者间关系及对α-synuclein外泌体在邻近DA能神经元间播散行为的调节，为PD病因和疾病进展研究及干预治疗提供有价值的新线索。

帕金森病（PD）的发病机制目前尚不明确，已有证据表明α-突触核蛋白（α-synuclein）可通过外泌体在邻近多巴胺能（DA）神经元间播散并产生损伤作，促进PD的发生和发展。申请者前期研究发现VPS35作为逆运复合体的重要组成部分，其致病突变D620N可增加细胞内α-synuclein的外泌体分泌。为探索VPS35调节α-synuclein外泌体分泌的具体机制，我们首先构建了可以稳定内源表达VPS35致病突变D620N的转基因鼠，明确了VPS35 D620N小鼠出现帕金森病运动表型及黑质-纹状体多巴胺能通路退行性变。随后通过在体及离体实验证实D620N突变可引起α-synuclein的升高聚集及外泌体α-synuclein的分泌增多。进一步机制研究发现，VPS35 D620N突变可下调溶酶体相关膜蛋白2A (Lamp2a)的表达，VPS35识别并促进Lamp2a的逆转运内体回收，VPS35 D620N突变影响了逆转运复合体功能，导致Lamp2a逆转运回收障碍，引起了Lamp2a介导的外泌体α-syn降解减少，最终导致α-syn外泌体分泌增多。本项目的开展为探索PD的发病机制及PD新的治疗途径提供了有价值的新线索。