Rapid FRET Assay for the Early Detection of Alpha-Synuclein Aggregation in Parkinson's Disease

Alpha-synuclein (alpha-Syn) is a key protein of Parkinson's disease (PD). Oligomers formed by misfolding and aggregation of alpha-Syn can cause many pathological phenomena and aggravate the development of PD. Therefore, sensitive and accurate detection of oligomers is essential to understanding the pathology of PD and beneficial to screening and developing new drugs against PD. Here, we demonstrated a simple and sensitive method to detect the early aggregation of alpha-Syn via Fo''rster resonance energy transfer (FRET) technology. We performed systematic investigations of the FRET sensitizations, efficiencies, and donor-to-acceptor distances during alpha-Syn aggregation, which was proved to be more sensitive to reflect small distance changes in the early stage of alpha-Syn aggregation, especially for alpha-Syn oligomers. The FRET assays were also applied to study the influence of Ser129 phosphorylation (pS129) on the aggregation rate of alpha-Syn. Our results showed that pS129 modification promotes alpha-Syn aggregation and enhances the ability of preformed fibrils to induce monomer aggregation. pS129 also increased the cytotoxicity of alpha-Syn. These results are of great significance for a better understanding of the pathological mechanisms of PD and future PD drug development.