Parkinson’s disease (PD) affects more than one million people in the United States alone, making it the second most common neurodegenerative disorder in the US. In PD, aggregates of the protein α-Synuclein (α-Syn) are known to induce the death of dopamine-producing cells in the substantia nigra, reducing dopamine production and ultimately hindering cognitive function. Although monomeric α-Syn is natively unfolded and likely regulates vesicle trafficking, mutations and protein damage (such as from oxidative stress) can promote its aggregation into oligomers and fibrils rich in β-sheet content. α-Syn oligomers, in particular, have been observed to be cytotoxic by increasing membrane permeability and promoting membrane damage. However, the distinct nature and propagation of this disruption have yet to be characterized. This work used scanning ion conductance microscopy (SICM) – a method of three-dimensional imaging that uses a glass micropipette probe - to image in real time the topographies of SH-SY5Y neuroblastoma cell membranes after the addition of α-Syn aggregates. α-Syn aggregates were produced in-vitro and characterized by atomic force microscopy (AFM) and circular dichroism (CD) spectroscopy. Significant damage to the cell membrane was observed, with both large defects and small pore-like structures spreading across the membrane over time. This suggested that the α-Syn aggregates may themselves be binding to and disrupting the membrane. Current work aims to determine whether α-Syn aggregates may independently bind to cell membranes and whether they may form transmembrane pores. Overall, this work has used scanning ion conductance microscopy as a novel method for monitoring in real time damage to neuroblastoma cell membranes and has suggested membrane integration as a mechanism of α-Syn-induced cell death.

Real-time monitoring of α-synuclein-induced cell membrane disruption in Parkinson’s disease by scanning ion conductance microscopy

2019 Fall National Meeting

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