Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
Sei Imura
Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan; Laboratory of Molecular Neuroscience, Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan
Masato Hosokawa
Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
Ryu Katsumata
Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
Abnormal α-synuclein aggregation has been implicated in several diseases and is known to spread in a prion-like manner. There is a relationship between protein aggregate structure (strain) and clinical phenotype in prion diseases, however, whether differences in the strains of α-synuclein aggregates account for the different pathologies remained unclear. Here, we generated two types of α-synuclein fibrils from identical monomer and investigated their seeding and propagation ability in mice and primary-cultured neurons. One α-synuclein fibril induced marked accumulation of phosphorylated α-synuclein and ubiquitinated protein aggregates, while the other did not, indicating the formation of α-synuclein two strains. Notably, the former α-synuclein strain inhibited proteasome activity and co-precipitated with 26S proteasome complex. Further examination indicated that structural differences in the C-terminal region of α-synuclein strains lead to different effects on proteasome activity. These results provide a possible molecular mechanism to account for the different pathologies induced by different α-synuclein strains.
