Differentiation and characterization of conformational alpha-synuclein strains associated with Parkinson's disease and related synucleinopathies

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Synucleinopathies are a diverse group of neurodegenerative diseases characterized by misfolding, aggregation and accumulation of misfolded alpha-synuclein (αSyn) which include Parkinson‘s disease (PD), multiple system atrophy (MSA) and dementia with Lewy bodies (DLB). Despite sharing the same pathological protein, different clinical and pathological phenotypes are typically observed in different synucleinopathies. One of the main obstacles to develop effective treatments for synucleinopathies is the lack of an early diagnosis before the onset of brain damage and clinical symptoms of the disease. Clinically, it is very challenging to discriminate between some of the synucleinopathies (e.g. PD and MSA), especially at early stages of the disease. This is an important problem because these diseases have different prognosis and modes of treatment. Recently, we developed the protein misfolding cyclic amplification (PMCA, also known as RT- QuIC) technology for highly sensitive and specific detection of αSyn oligomers in biological fluids of patients affected by synucleinopathies. αSyn-PMCA utilizes the prion-like seeding mechanism to cyclically amplify the process of protein misfolding, enabling the efficient amplification of small quantities of αSyn oligomers, facilitating their detection. We have evidence that the product of αSyn-PMCA coming from CSF samples of patients affected by PD and MSA can be experimentally distinguished. Thus, we hypothesize that αSyn aggregates associated with different synucleinopathies correspond to different conformational strains/ sub-strains of αSyn that can be faithfully amplified by αSyn-PMCA and the product can be differentiated by their biochemical, structural and biological properties. In this study, our main goal is to detect, differentiate and amplify minute amounts of αSyn strains/ sub-strains from biological fluids and brain tissue of patients with synucleinopathies by an in-vitro seeding/ amplification assay, and characterize these αSyn conformational aggregates using various biochemical, structural, and biological techniques. The findings obtained here will lay the foundation towards the development of a biochemical test for differential diagnosis of synucleinopathies by sensitive and specific detection of different αSyn strains/sub-strains, which will help in patients’ stratification, target enrollment for clinical trial and personalized treatment.