Aggregates of the natively unfolded protein α-synuclein (α-Syn) have been widely implicated in the development of Parkinson’s disease, a neurodegenerative disorder involving the death of dopaminergic neurons. Mutations, protein overaccumulation, and oxidative stress can promote the aggregation of α-Syn into oligomers and fibrils. Recent work has suggested that ellipsoidal α-Syn oligomers can permeabilize the plasma membrane, promoting Ca2+ influx and cell death. However, the mechanism of this permeabilization is still debated and has yet to be characterized in live cells. This work uses scanning ion conductance microscopy (SICM) to image, in real time, the topographies of live SH-SY5Y neuroblastoma cells after exposure to α-Syn oligomers. The α-Syn aggregates were produced in-vitro and were characterized by atomic force microscopy and circular dichroism spectroscopy. Significant damage to the neuroblastoma cell membrane was observed, with significant distortions and curvature changes observed at lower α-Syn concentrations (1.00 μM) and large pores in the membrane observed at higher α-Syn concentrations (6.0 μM). These findings suggest that α-Syn oligomers may permeabilize the neuronal membrane through bilayer destabilization and the opening of transient pores in the membrane. This work also demonstrates that SICM can be used to monitor the disruption of live cell membranes in real time.

Real-time characterization of cell membrane disruption by α-synuclein aggregates in Parkinson’s disease

ACS Fall 2020 Virtual Meeting

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