title: Dopamine facilitates alpha-synuclein oligomerization in human neuroblastoma SH-SY5Y cells.
abstract: Parkinson's disease is characterized by selective loss of dopaminergic neurons in the substantia nigra and by the appearance of Lewy bodies. Fibrillar alpha-synuclein is the main component of Lewy bodies. Previous studies have suggested that dopamine promotes alpha-synuclein oligomerization and that partially aggregated or oligomeric alpha-synuclein could be cytotoxic. To confirm this hypothesis using cell cultures, we performed size exclusion chromatography as a pretreatment method prior to Western blotting to more clearly detect a small amount of alpha-synuclein oligomers in wild-type alpha-synuclein-overexpressing SH-SY5Y cells. Using this method, we confirmed that stable overexpression of alpha-synuclein in SH-SY5Y cells indeed increased the amounts of alpha-synuclein oligomers in these cells and exposure of the cells to dopamine for 6h facilitated alpha-synuclein oligomerization. These dopamine-induced alpha-synuclein oligomers continued to exist for the following 24h. However, the dopamine-treated cells did not undergo cell death or apoptosis in spite of the presence of increased oligomeric alpha-synuclein. Our data may contribute to the understanding of the mechanisms underlying alpha-synuclein oligomer formation and its suspected cytotoxicity toward dopaminergic neurons.
authors.affiliation: Clinical Research Center, Utano National Hospital, National Hospital Organization, Kyoto 616-8255, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yamakawa
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Izumi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kume
authors.forename: Akinori
authors.initials: A
authors.lastname: Akaike
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Takahashi
authors.forename: Shun
authors.initials: S
authors.lastname: Shimohama
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Sawada
mesh_terms: D017209:Apoptosis; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002850:Chromatography, Gel; D004298:Dopamine / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D016631:Lewy Bodies / Q000737:chemistry / Q000378:metabolism; D009474:Neurons / Q000737:chemistry / Q000378:metabolism*; D010300:Parkinson Disease / Q000378:metabolism*; D013378:Substantia Nigra / Q000378:metabolism; D051844:alpha-Synuclein / Q000737:chemistry / Q000378:metabolism*
chemical_list: D051844:alpha-Synuclein; D004298:Dopamine