Discriminating α-synuclein strains in Parkinson's disease and multiple system atrophy

Area of Science:

• Neuroscience
• Biochemistry
• Pathology

Background:

• Synucleinopathies, including Parkinson's disease (PD) and multiple system atrophy (MSA), involve misfolded alpha-synuclein aggregates.
• Distinguishing between PD and MSA clinically, especially early on, remains a significant challenge.
• Distinct alpha-synuclein aggregate conformations are hypothesized to represent different strains driving disease progression.

Purpose of the Study:

• To develop and validate an assay capable of discriminating between Parkinson's disease and multiple system atrophy.
• To investigate whether distinct alpha-synuclein aggregate conformations in cerebrospinal fluid (CSF) correlate with specific synucleinopathies.
• To explore the potential of alpha-synuclein-PMCA as a diagnostic tool for differentiating PD and MSA.

Main Methods:

• Utilized protein misfolding cyclic amplification (PMCA) to detect and amplify alpha-synuclein aggregates in CSF samples.
• Employed a combination of biochemical, biophysical, and biological techniques to analyze amplified alpha-synuclein aggregates.
• Compared amplified aggregates from CSF with those from brain tissue to assess strain similarity.

Main Results:

• The alpha-synuclein-PMCA assay successfully differentiated between PD and MSA patient CSF samples with 95.4% sensitivity.
• Analysis revealed distinct biochemical and biophysical characteristics of amplified alpha-synuclein aggregates from PD versus MSA.
• Amplified aggregates from CSF mirrored the properties of those found in brain tissue, suggesting conserved strain characteristics.

Conclusions:

• Alpha-synuclein aggregates in Parkinson's disease and multiple system atrophy represent distinct conformational strains.
• The alpha-synuclein-PMCA assay is a sensitive and specific tool for distinguishing between PD and MSA.
• These findings support the development of a biochemical diagnostic assay for synucleinopathies.