Chaperone-mediated Autophagy and Synaptic Dysfunction in Parkinson's Disease

帕金森病(PD)是第二常见的神经退行性疾病，其特征是 黑质致密部多巴胺能神经元变性丢失。细胞和细胞的研究 动物模型和帕金森病患者死后脑研究表明，环境因素引发的突触功能障碍 遗传应激是帕金森病发病的早期事件。然而，精确和关键的机制 帕金森病的潜在突触功能障碍尚不清楚。液泡型(H)-ATPase(V-ATPase)是一种 依赖的质子泵参与了突触小泡的酸化，并在多个步骤中发挥关键作用 突触囊泡的生命周期，如与突触前膜的融合和神经递质的释放/重新加载。 我们的初步研究表明，突触V-ATPase可能受伴侣介导的自噬控制 (CMA)，一种基于溶酶体的过程，专门处理氧化或受损的蛋白质以降解为 在压力下维持细胞功能。值得注意的是，CMA受到与以下相关的多种压力条件的抑制 帕金森病包括衰老、神经毒性应激、氧化应激、内质网应激和遗传应激。然而，无论是和 细胞应激信号和CMA如何参与V-ATPase调节突触功能尚不清楚。在 目前的项目，通过利用多种模型系统，包括尖端的人类诱导多能干细胞 (IPSC)模型、在体啮齿动物模型(内质网和鼠脑的遗传应激)和死后帕金森病患者 我们的目标是确定CMA是否直接将突触V-ATPase的受损成分降解为 应激下维持突触小泡功能，以及CMA活性丧失是否损害突触 在帕金森病中的作用。首先，我们将从生物化学、细胞生物学和电生理学方面确定CMA 直接调节人IPSCs来源的DA神经元的突触V-ATPase和突触功能。第二, 我们将测试与帕金森病相关的多种应激条件是否通过CMA调节突触V-ATPase和功能 人IPSC来源的DA神经元。最后，我们将评估CMA-V-ATPase-突触的调节和作用 多种帕金森病动物模型和帕金森病患者死后脑内的囊泡通路。我们建议的研究 将极大地提高我们对应激如何调节突触小泡的理解，揭示一个关键的致病因素 帕金森病突触功能衰竭的机制及其发展的新机遇 疾病的诊断/生物标志物和更有效的预防和治疗策略。

Parkinson's disease (PD) is the second most common neurodegenerative disease characterized by the degenerative loss of dopaminergic (DA) neurons in the substantia nigra pars compacta. Studies of cellular and animal models and postmortem PD patient brains reveal that synaptic dysfunction triggered by environmental and genetic stress is an early event in PD pathogenesis. However, the precise and key mechanisms that underlie synaptic dysfunction in PD remain to be defined. The vacuolar (H+)-ATPase (V-ATPase) is an ATP- dependent proton pump involved in acidifying synaptic vesicles and plays a critical role in multiple steps of synaptic vesicle life cycle such as fusion with pre-synaptic membrane and neurotransmitter release/reloading. Our preliminary studies show that synaptic V-ATPase may be controlled by chaperone-mediated autophagy (CMA), a lysosome-based process specialized in disposing oxidized or damaged proteins for degradation to maintain cellular function under stress. Notably, CMA is inhibited by multiple stress conditions associated with PD including aging, neurotoxic stress, oxidative stress, ER stress, and genetic stress. However, whether and how cellular stress signals and CMA engage V-ATPase to modulate synaptic function is still unknown. In the current project, by utilizing multiple model systems, including cutting-edge human induced pluripotent stem cell (iPSC) model, in vivo rodent models (ER and genetic stress of rodent brains), and postmortem PD patient brains, we aim to determine whether CMA directly degrades damaged components of synaptic V-ATPase to maintain synaptic vesicle function under stress, and whether loss of adequate CMA activity impairs synaptic function in PD. First, we will determine biochemically, cell biologically, and electro-physiologically if CMA directly regulates synaptic V-ATPase and synaptic function in DA neurons derived from human iPSCs. Second, we will test if multiple stress conditions related to PD regulate synaptic V-ATPase and function via CMA in human iPSC-derived DA neurons. Last, we will assess the regulation and role of CMA–V-ATPase–synaptic vesicle pathway in multiple PD animal models and in postmortem brains from PD patients. Our proposed study will significantly advance our understanding of how stress regulates synaptic vesicle, reveal a key pathogenic mechanism underlying synaptic failure in PD, and offer new opportunities for developing diagnostics/biomarkers and more effective prevention and treatment strategies for the disease.