Different structures and pathologies of α-synuclein fibrils derived from preclinical and postmortem patients of Parkinson’s disease

alpha-Synuclein (alpha-syn) fibrillar aggregates are the major component of Lewy bodies and Lewy neurites presenting as the pathology hallmark of Parkinson9s disease (PD). Studies have shown that alpha-syn is potential to form different conformational fibrils associated with different synucleinopathies, but whether the conformation of alpha-syn fibrils changes in different phases of related diseases is to be explored. Here, we amplified alpha-syn aggregates from the cerebrospinal fluid (CSF) of preclinical (pre-PD) and late-stage postmortem PD (post-PD) patients. Our results show that compared to the CSF of pre-PD, that of post-PD is markedly stronger in seeding in vitro alpha-syn aggregation, and the amplified fibrils are more potent in inducing endogenous alpha-syn aggregation in neurons. Cryo-electron microscopic structures further reveal that the difference between the pre-PD- and post-PD-derived fibrils lies on a minor polymorph which in the pre-PD fibrils is morphologically straight, while in the post-PD fibrils represents a single protofilament assembled by a distinctive conformation of alpha-syn. Our work demonstrates structural and pathological differences between pre-PD and post-PD alpha-syn aggregation and suggests potential alteration of alpha-syn fibrils during the progression of PD clinical phases.