Autophagy modulates alpha-Synuclein cellular pathology and exosome associated release

包括帕金森病(PD)和路易体痴呆(DLB)在内的联体核病的特点是胞浆和神经元包涵体(路易小体，LBS和路易神经节，LNS)由错误折叠和聚集的α-突触核蛋白aSyn组成。作为泛素-蛋白酶体降解系统(UPS)的补充，aSyn通过自噬-溶酶体途径(ALP)被降解。最近，我们在体外和体内的aSyn聚集模型中分析了ALP对aSyn聚集形式的作用，其中我们发现ALP不仅对aSyn的聚集和毒性起直接作用，而且令人惊讶的是还对aSyn的细胞外释放起直接作用(autophagy 2012,2014)。多囊体室(MVB)可能是将细胞内降解与细胞外释放和病理联系起来的相互联系的细胞机制。由于外切体来源于MVB，并且最近与aSyn释放机制相关，本基金旨在了解1)ALP调节是否影响细胞内aSyn病理并诱导外切体依赖的aSyn释放机制，2)由MVB衍生的外切体分泌途径(ESP)释放的有毒aSyn物种与自噬调节的降解途径(ALP)相交，以及3)ALP和ESP调节是否影响神经元(繁殖)和神经胶质细胞(促炎)对释放的aSyn的细胞外反应，从而参与其病理机制。将在人类aSyn细胞培养模型中研究细胞内病理、细胞外释放和对神经细胞的反应。同时，第二组实验将在人类aSyn启动子驱动的aSyn转基因小鼠的原代神经元培养中测试这些效应(在aSyn k.o.背景)，以及在神经共培养中。综上所述，该项目将结合碱性磷酸酶在细胞内aSyn上的重要作用和最近发现的细胞外aSyn在神经元-神经胶质细胞通讯、转移、毒性和疾病进展中的作用。

Synucleinopathies including Parkinson disease (PD) and Dementia with Lewy bodies (DLB) are characterized by cytoplasmic and neuritic inclusions (Lewy bodies, LBs, and Lewy neurites, LNs) composed of misfolded and aggregated forms of alpha-synuclein aSyn. Complementary to the ubiquitin-proteasome degradation system (UPS) aSyn is degraded by the autophagy-lysosomal pathway (ALP). Recently, we analyzed the role of the ALP on aggregated forms of aSyn in vitro and in vivo models of aSyn aggregation where we identified a direct role of ALP not only on aSyn aggregation and toxicity, but surprisingly also to extracellular release of aSyn (Autophagy 2012, 2014). The multivesicular body compartment (MVB) might be the interconnecting cellular mechanism that links intracellular degradation to extracellular release and pathology. Since exosomes derive form MVB and have recently associated with aSyn release mechanisms, the present grant aims to understand if 1) ALP modulation affects intracellular aSyn pathology and induces exosome-dependent aSyn release mechanisms, 2) toxic aSyn species released by the exosome secretion pathway (ESP) derived from the MVB intersect with the autophagy modulated degradation pathways (ALP), and 3) if ALP and ESP modulation affects the extracellular response of neuronal (propagation) and glial cells (proinflammation) to released aSyn and thereby contributes to its pathomechanism. Intracellular pathology, extracellular release and response to neural cells will be studied in human aSyn cell culture models. In parallel, a second set of experiments will test these effects in primary neuronal cultures from human aSyn promoter driven aSyn transgenic mice (on aSyn k.o. background), and in neural cocultures. In summary, the proposed project will integrate the important role of ALP on intracellular aSyn with the recently identified role of extracellular aSyn in neuronal-glial communication, transfer, toxicity, and disease progression.