Seeded assembly in vitro does not replicate the structures of α-synuclein filaments from multiple system atrophy

Area of Science:

• Neuroscience
• Biochemistry
• Structural Biology

Background:

• Prion-like propagation of misfolded alpha-synuclein underlies neurodegenerative diseases such as Parkinson's disease, dementia with Lewy bodies (DLB), and multiple system atrophy (MSA).
• Understanding the mechanisms of alpha-synuclein filament assembly and propagation is crucial for developing therapeutic strategies.

Purpose of the Study:

• To investigate the in vitro seeded assembly of alpha-synuclein using pre-formed filaments from multiple system atrophy (MSA) brains.
• To compare the structures of in vitro seeded alpha-synuclein assemblies with the original seed structures.

Main Methods:

• Utilized filament preparations from the putamen of three individuals diagnosed with MSA.
• Performed in vitro seeded assembly experiments using recombinant human alpha-synuclein.

Main Results:

• The atomic structures of the in vitro seeded alpha-synuclein assemblies were found to be different from the structures of the original MSA-derived seeds.
• This structural divergence suggests that the templated seeding process is not solely determined by the seed structure.

Conclusions:

• Additional, currently unidentified factors are likely involved in the propagation of alpha-synuclein seeds in prion-like spreading.
• Identifying these factors is essential for a comprehensive understanding of alpha-synuclein proteinopathies and their prion-like dissemination.