Category: Parkinsonism, Atypical: MSA
Objective: The objective of our work was to develop a novel high-throughput cell-free assay that allowed us to perform a comprehensive characterization of α-synuclein seeding capacity in the human brain in relation to pathology in Multiple System Atrophy.
Background: Synucleinopathies are a group of neurodegenerative diseases, including multiple system atrophy (MSA) and Parkinson’s disease (PD), associated with the misfolding and aggregation of α-synuclein. Accumulating evidence has shown that disease-associated α-synuclein is able to self-propagate and spread from cell to cell. Furthermore, recent evidence suggests that the structure of the protein aggregates may differ between different synucleinopathies. Several methods are able to detect and study α-synuclein aggregates in the brain and cerebrospinal fluid of PD patients but, to date, there is no method able to detect the α-synuclein aggregates from MSA patients.
Method: We designed a novel high-throughput fluorescence assay, based on the amplification of α-synuclein oligomers, to detect MSA derived α-synuclein and to evaluate the seeding capacity of MSA aggregates derived from brain homogenates of 15 MSA patients compared to 15 PD patients. We used a combination of biochemical, biophysical, molecular biological, and neuropathological methods to validate this novel assay. We performed a comprehensive analysis of alpha-synuclein burden in 15 most vulnerable brain regions from 2 well-characterized MSA patients.
Results: Our assay detected aggregates in the brain samples from all patients diagnosed with MSA and differentiated them from those in the brains of patients with PD with an overall sensitivity of 98 %. Interestingly, our data also revealed striking differences in the seeding capacity of the MSA-α-synuclein aggregates both between the two cases and different brain regions, which might be correlated with the size and cellular location of these aggregates.
Conclusion: To our knowledge, we are the first to describe a method able to specifically detect α-synuclein aggregates in MSA. This novel method has allowed us to perform the first comprehensive characterization of α-synuclein seeding capacity in the human brain in relation to pathology in MSA. These results enhance our understanding of the mechanisms of α-synuclein misfolding and underlying pathogenesis in MSA.
To cite this abstract in AMA style:I. Martinez-Valbuena, N. P. Visanji, A. Kim, S. Lee, S. Alshimemeri, R. So, A. Gao, J. C. Watts, A. Lang, G. G. Kovacs. Mapping regional alpha-synuclein seeding capacity in Multiple System Atrophy [abstract]. Mov Disord. 2021; 36 (suppl 1). https://www.mdsabstracts.org/abstract/mapping-regional-alpha-synuclein-seeding-capacity-in-multiple-system-atrophy/. Accessed December 7, 2023.
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MDS Abstracts - https://www.mdsabstracts.org/abstract/mapping-regional-alpha-synuclein-seeding-capacity-in-multiple-system-atrophy/