Observation of α-Synuclein Preformed Fibrils Interacting with SH-SY5Y Neuroblastoma Cell Membranes Using Scanning Ion Conductance Microscopy

Parkinson's disease (PD) is the second-most prevalent neurodegenerative disorder in the U.S. alpha-Synuclein (alpha-Syn) preformed fibrils (PFFs) have been shown to propagate PD pathology in neuronal populations. However, little work has directly characterized the morphological changes on membranes associated with alpha-Syn PFFs at a cellular level. Scanning ion conductance microscopy (SICM) is a noninvasive in situ cell imaging technique and therefore uniquely advantageous to investigate PFF-induced membrane changes in neuroblastoma cells. The present work used SICM to monitor cytoplasmic membrane changes of SH-SY5Y neuroblastoma cells after incubation with varying concentrations of alpha-Syn PFFs. Cell membrane roughness significantly increased as the concentration of alpha-Syn PFFs increased. Noticeable protrusions that assumed a more crystalline appearance at higher alpha-Syn PFF concentrations were also observed. Cell viability was only slightly reduced, though statistically significantly, to about 80% but independent of the dose. These observations indicate that within the 48 h treatment period, PFFs continue to accumulate on the cell membranes, leading to membrane roughness increase without causing prominent cell death. Since PFFs did not induce major cell death, these data suggest that early interventions targeting fibrils before further aggregation may prevent the progression of neuron loss in Parkinson's disease.

Automated summary

By using scanning ion conductance microscopy (SICM), this study monitored the membrane changes induced by alpha-Syn preformed fibrils (PFFs) in neuroblastoma cells. The results showed that as the concentration of PFFs increased, the roughness of the cell membranes significantly increased, and noticeable protrusions with a more crystalline appearance were observed. Cell viability was slightly reduced, but not dependent on the dose.