Numerous pathological amyloid proteins spread from cell to cell during neurodegenerative disease, facilitating the propagation of cellular pathology and disease progression. Understanding the mechanism by which disease-associated amyloid protein assemblies enter target cells and induce cellular dysfunction is, therefore, key to understanding the progressive nature of such neurodegenerative diseases. In this study, we utilized an imaging-based assay to monitor the ability of disease-associated amyloid assemblies to rupture intracellular vesicles following endocytosis. We observe that the ability to induce vesicle rupture is a common feature of α-synuclein (α-syn) assemblies, as assemblies derived from WT or familial disease-associated mutant α-syn all exhibited the ability to induce vesicle rupture. Similarly, different conformational strains of WT α-syn assemblies, but not monomeric or oligomeric forms, efficiently induced vesicle rupture following endocytosis. The ability to induce vesicle rupture was not specific to α-syn, as amyloid assemblies of tau and huntingtin Exon1 with pathologic polyglutamine repeats also exhibited the ability to induce vesicle rupture. We also observe that vesicles ruptured by α-syn are positive for the autophagic marker LC3 and can accumulate and fuse into large, intracellular structures resembling Lewy bodies in vitro. Finally, we show that the same markers of vesicle rupture surround Lewy bodies in brain sections from PD patients. These data underscore the importance of this conserved endocytic vesicle rupture event as a damaging mechanism of cellular invasion by amyloid assemblies of multiple neurodegenerative disease-associated proteins, and suggest that proteinaceous inclusions such as Lewy bodies form as a consequence of continued fusion of autophagic vesicles in cells unable to degrade ruptured vesicles and their amyloid contents.

在神经退行性疾病期间，许多病理性淀粉样蛋白在细胞之间扩散，从而促进了细胞病理学的传播和疾病的发展。因此，了解与疾病相关的淀粉样蛋白组装体进入靶细胞并诱导细胞功能障碍的机制是理解此类神经退行性疾病的进行性的关键。在这项研究中，我们利用基于成像的检测方法来监测与疾病相关的淀粉样蛋白组装在胞吞作用后破裂细胞内囊泡的能力。我们观察到，诱导囊泡破裂的能力是α-突触核蛋白（α-syn）装配的共同特征，因为衍生自WT或家族性疾病相关突变α-syn的装配均表现出诱导囊泡破裂的能力。相似地，WTα-syn装配体的不同构象菌株，而不是单体或寡聚体形式，在胞吞作用后有效诱导囊泡破裂。诱导囊泡破裂的能力不是α-syn特异的，因为带有病理性聚谷氨酰胺重复序列的tau和huntingtin Exon1的淀粉样蛋白组装物也具有诱导囊泡破裂的能力。我们还观察到，α-syn破裂的囊泡对于自噬标记物LC3呈阳性，并且可以在体外积聚并融合成类似于路易体的大的细胞内结构。最后，我们显示了来自PD患者脑切片中路易小体的囊泡破裂标记物相同。