Study finds α-synuclein strain homogeneity across multiple system atrophy subtypes
A new preprint study found that the two clinical subtypes of multiple system atrophy (MSA-C and MSA-P) appear to share the same conformational strain of α-synuclein aggregates, rather than harboring distinct strains. Researchers used biochemical fingerprinting, conformational stability assays, seed amplification assays, and transgenic mouse propagation studies across multiple brain regions to reach this conclusion. The findings challenge a leading hypothesis about what drives clinical diversity in synucleinopathies and suggest that where aggregates first form in the brain—not what type they are—may determine disease presentation.
Researchers publishing on bioRxiv investigated whether the two recognized clinical subtypes of multiple system atrophy—the cerebellar variant (MSA-C) and the parkinsonian variant (MSA-P)—are driven by conformationally distinct strains of α-synuclein aggregates, a hypothesis drawn from the broader concept of prion-like strain diversity in neurodegenerative diseases. Using brain tissue from MSA-C and MSA-P patients, the team applied limited proteolysis and conformational stability assays to biochemically fingerprint α-synuclein aggregates, finding no detectable differences between the two subtypes. Seed amplification assays using both patient brain extracts and extracts from inoculated M83 transgenic mice also showed indistinguishable seeding properties across subtypes. Furthermore, when M83 mice were inoculated with α-synuclein from either MSA-C or MSA-P sources—regardless of the originating brain region—no differences emerged in disease progression kinetics or the extent of cerebral α-synuclein deposition. The authors propose an alternative model in which a single α-synuclein strain forms in different anatomical regions of the brain, and it is this regional origin, rather than strain identity, that gives rise to the distinct clinical manifestations seen in MSA subtypes.
What's missing
As a preprint, this study has not yet undergone formal peer review, and its conclusions should be treated as preliminary.
What different sources said
- bioRxivCenter
α-Synuclein strain homogeneity in multiple system atrophy clinical subtypes
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