溶酶体ATP13A2对帕金森病模型小鼠脑内Caspase-1介导的神经元焦亡的调控及机制研究

ATP13A2 is localized, at least in part, to lysosomes where it may participate in the ATP dependent transport of cations across vesicular membranes. It has been clarified that α-synuclein, the characteristic pathologic marker in Parkinson's disease (PD), degrades through ATP13A2-mediated autophagy-lysosomal pathway, and ATP13A2 even been regarded as the related gene of PD. Our group had found that the deficiency of ATP13A2 not only induced dopaminergic neuronal damage by autophagy-lysosomal pathway, but also accompanied by the activation of inflammasome, the cleavage of caspase-1 and gasdermin D (GSDMD) protein in neuronal pyroptosis, whereas the underlying pathological mechanism remains unclear. In the present study, we intend to investigate the regulatory effects of ATP13A2 on dopaminergic neuronal pyroptosis with ATP13A2+/+ and ATP13A2-/- mice in vivo and in vitro. We propose that ATP13A2 involves the pathogenesis of PD via regulating the neuronal pyroptosis and neurodegeneration. These findings will give us an insight into the immune regulation in the pathological process of PD, and provide new targets and experimental evidences for therapeutics in PD.

ATP13A2作为溶酶体膜上的阳离子转运体，在脑内通过调控自噬-溶酶体通路促进帕金森病（PD）特征性病理标志物α-突触核蛋白的降解，被视为PD相关基因。申请者前期研究发现ATP13A2敲除不仅影响自噬-溶酶体而诱导小鼠多巴胺能（DA）神经元损伤，还伴有炎症小体组装激活、Caspase-1活化、GSDMD蛋白切割成熟等DA能神经元焦亡的现象。然而，ATP13A2是否通过调节神经免疫和细胞焦亡信号通路参与PD的DA能神经元退行性病变及其机制目前尚不清楚。本项目拟在前期研究工作基础上，应用已制备的ATP13A2敲除鼠建立MPTP/p PD模型，在整体、细胞和分子水平研究阐明ATP13A2对中脑DA神经元焦亡的调节作用和分子机制，揭示ATP13A2调控神经元焦亡与PD发生的相关性。研究成果不仅有助于深化认识免疫调控在PD病理进程中的作用，也为靶向溶酶体研发理想的PD治疗药物提供新的靶标和实验依据。

ATP13A2（又称为Park9）是一种溶酶体膜上的阳离子转运体，维持溶酶体膜结构的稳定性和膜内酸性环境的稳态，在脑内通过调控自噬-溶酶体通路促进帕金森病（PD）特征性病理标志物α-突触核蛋白的降解，被视为早期诱导PD发生的相关基因。本项目在前期研究发现ATP13A2敲除诱导小鼠多巴胺能（DA）神经元损伤的基础上，还伴有炎症小体组装激活、Caspase-1活化、GSDMD蛋白切割成熟等DA能神经元焦亡的现象，进一步应用ATP13A2敲除鼠和Caspase-1敲除鼠系统研究ATP13A2在PD发生发展中的重要作用，在整体和细胞水平阐明ATP13A2对中脑DA神经元焦亡的调节作用和分子机制，揭示溶酶体ATP13A2在抗PD治疗中的意义和价值。研究发现：1）PD病理进程中DA能神经元死亡的新的方式——细胞焦亡；2）ATP13A2敲除促进DA能神经元焦亡，参与PD发生发展；3）ATP13A2敲除促进MPTP诱导的NLRP3-Caspase-1炎症小体激活和神经元细胞焦亡；4）Caspase-1敲除减轻MPTP诱导的神经元焦亡；5）中枢SNc脑区敲减NLRP3，减轻中脑DA能神经元焦亡；6）外周肝脏敲减NLRP3，抑制中枢炎症，减少神经元焦亡。上述研究成果不仅有助于深化认识免疫调控在PD病理进程中的作用，也为靶向溶酶体研发理想的PD治疗药物提供新的思路。