Search academic texts

Information × Registration Number 2118U003939, Article popup.category Стаття Title popup.author popup.publication 01-01-2018 popup.source_user Сумський державний університет popup.source http://essuir.sumdu.edu.ua/handle/123456789/68102 popup.publisher BMC Description Background:Chronic neuroinflammation is a hallmark of Parkinson’s disease (PD) pathophysiology, associated with increased levels of pro-inflammatory factors in PD brain tissues. The pro-inflammatory mediator and highly amyloidogenic protein S100A9 is involved in the amyloid-neuroinflammatory cascade in Alzheimer’s disease. This is the first report on the co-aggregation ofα-synuclein (α-syn) and S100A9 both in vitro and ex vivo in PD brain. Methods:Single and sequential immunohistochemistry, immunofluorescence, scanning electron and atomic force (AFM) microscopies were used to analyze theex vivo PD brain tissues for S100A9 andα-syn location and aggregation. In vitro studies revealing S100A9 andα-syn interaction and co-aggregation were conducted by NMR, circular dichroism, Thioflavin-T fluorescence, AFM, and surface plasmon resonance methods. Results:Co-localized and co-aggregated S100A9 andα-syn were found in 20% Lewy bodies and 77% neuronal cells in the substantia nigra; both proteins were also observed in Lewy bodies in PD frontal lobe (Braak stages 4–6). Lewy bodies were characterized by ca. 10–23μm outer diameter, with S100A9 andα-syn being co-localized in the same lamellar structures. S100A9 was also detected in neurons and blood vessels of the aged patients without PD, but in much lesser extent. In vitro S100A9 andα-syn were shown to interact with each other via the α-syn C-terminus with an apparent dissociation constant of ca. 5 μM. Their co-aggregation occurred significantly faster and led to formation of larger amyloid aggregates than the self-assembly of individual proteins. S100A9 amyloid oligomers were more toxic than those ofα-syn, while co-aggregation of both proteins mitigated the cytotoxicity of S100A9 oligomers. Conclusions:We suggest that sustained neuroinflammation promoting the spread of amyloidogenic S100A9 in the brain tissues may trigger the amyloid cascade involving α-syn and S100A9 and leading to PD, similar to the effect of S100A9 and Aβco-aggregation in Alzheimer’s disease. The finding of S100A9 involvement in PD may open a new avenue for therapeutic interventions targeting S100A9 and preventing its amyloid self-assembly in affected brain tissues popup.nrat_date 2025-05-12 Close