Effect of the micro-environment on α-synuclein conversion and implication in seeded conversion assays

Background: α-Synuclein is a small soluble protein,whose physiological function in the healthy brain is poorly understood.Intracellular inclusions of α-synuclein,referred to as Lewy bodies(LBs),are pathological hallmarks ofαsynucleinopathies,such as Parkinson’s disease(PD)or dementia with Lewy bodies(DLB).Main body:Understanding of the molecular basis as well as the factors or conditions promoting α-synuclein misfolding and aggregation is an important step towards the comprehension of pathological mechanism ofαsynucleinopathies and for the development of efficient therapeutic strategies.Based on the conversion and aggregation mechanism of α-synuclein,novel diagnostic tests,such as protein misfolding seeded conversion assays,e.g.the real-time quaking-induced conversion(RT-QuIC),had been developed.In diagnostics, α-synuclein RT-QuIC exhibits a specificity between 82 and 100%while the sensitivity varies between 70 and 100%among different laboratories.In addition,the α-synuclein RT-QuIC can be used to study the α-synuclein-seeding-characteristics of different α-synucleinopathies and to differentiate between DLB and PD.Conclusion:The variable diagnostic accuracy of current α-synuclein RT-QuIC occurs due to different protocols,cohorts and material etc..An impact of micro-environmental factors on the α-synuclein aggregation and conversion process and the occurrence and detection of differential misfolded α-synuclein types or strains might underpin the clinical heterogeneity of α-synucleinopathies.