In vitro α-synuclein neurotoxicity and spreading among neurons and astrocytes using Lewy body extracts from Parkinson disease brains

Synucleinopathies are a group of diseases characterized by the presence of intracellular protein aggregates containing alpha-synuclein (alpha-syn). While alpha-syn aggregates have been shown to induce multimodal cellular dysfunctions, uptake and transport mechanisms remain unclear. Using high-content imaging on cortical neurons and astrocytes, we here define the kinetics of neuronal and astrocytic abnormalities induced by human-derived alpha-syn aggregates grounding the use of such system to identify and test putative therapeutic compounds. We then aimed at characterizing uptake and transport mechanisms using primary cultures of cortical neurons and astrocytes either in single well or in microfluidic chambers allowing connection between cells and cell-types. We report that astrocytes take up alpha-syn-aggregates far more efficiently than neurons through an endocytic event. We also highlight that active alpha-syn transport occurs between cells and any cell-types. Of special interest regarding the disease, we also show that uptake and spreading of alpha-syn from astrocytes to neurons can lead to neuronal death. Altogether, we here show that patients-derived alpha-synuclein aggregates, which are taken up by neurons and astrocytes, induce a differential endogenous response in the two cell types including a peculiar astrocytic toxic gain-of-function that leads to neuronal death. (C) 2017 Elsevier Inc. All rights reserved.