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PMCA AMPLIFIED ALPHA-SYNUCLEIN AGGREGATES FROM PD AND MSA CAN SEED AGGREGATION IN CELLS AND MAINTAIN THEIR STRAIN CHARACTERISTICS
Abstract
Aims
Parkinson’s disease (PD) and Multiple System Atrophy (MSA) are synucleinopathies with overlapping clinical symptoms, nevertheless, with different prognosis and neuropathological abnormalities. It is thought that the different disease characteristics are determined by distinct conformations of alpha-synuclein (αSyn) aggregates, which can self-propagate and spread between cells via a prion-like mechanism. Protein misfolding cyclic amplification (PMCA) is a technique that has been previously shown to detect with high sensitivity and specificity αSyn aggregates in cerebrospinal fluid and to discriminate between samples from patients diagnosed with PD and MSA. Our goal is to analyze whether PMCA amplification maintains the αSyn strain properties. For this purpose, we studied PMCA-amplified aggregates from patients’ CSF and brain samples in comparison with un-amplified patients’ brain homogenates.
Methods
We used biosensor HEK293T cell line stably expressing αSyn (A53T)-CFP/YFP fusion proteins to study αSyn seeding properties in cell culture.
Results
Our data show that PMCA-amplified αSyn aggregates from either CSF or brain homogenates were able to induce seeding in reporter cells. Importantly, differences in morphological features of αSyn accumulations in cells produced by PD or MSA amplified aggregates were indistinguishable from those observed when cells were exposed to un-amplified PD or MSA brain homogenates.
Conclusions
The present findings show that, regardless of the source of aggregates, PD and MSA seeds produce cellular accumulation of αSyn with different morphologies. These findings not only confirm the presence of different strains of αSyn in PD and MSA, but most importantly they also demonstrate that the seeding properties of PMCA amplified aggregates are maintained after amplification.