title: Dopamine affects the stability, hydration, and packing of protofibrils and fibrils of the wild type and variants of alpha-synuclein.
abstract: Parkinson's disease (PD) is characterized by the presence of cytoplasmic inclusions composed of alpha-synuclein (alpha-syn) in dopaminergic neurons. This suggests a pivotal role of dopamine (DA) on PD development. Here, we show that DA modulates differently the stability of protofibrils (PF) and fibrils (F) composed of wild type or variants of alpha-syn (A30P and A53T) as probed by high hydrostatic pressure (HHP). While in the absence of DA, all alpha-syn PF exhibited identical stability, in its presence, the variant-composed PF acquired a greater stability (DAPFwt < DAPFA30P = DAPFA53T), implying that they would last longer, which could shed light onto why these mutations are so aggressive. When alpha-syn was incubated for long times (18 days) in the presence of DA, we observed the formation of F by electronic microscopy, suggesting that the PF trapped in the presence of DA in short times can evolve into F. The stability of F was also altered by DA. DAFwt was more labile than Fwt, indicating that the former would be more susceptible to breakage. PFA30P and DAPFA30P, when added to mesencephalic and cortical neurons in culture, decreased the number and length of neurites and increased the number of apoptotic cells. Surprisingly, these toxic effects of PFA30P and DAPFA30P were practically abolished with HHP treatment, which was able to break the PF into smaller aggregates, as seen by atomic force microscopy. These results suggest that strategies aimed at breaking and/or clearing these aggregates is promising in alleviating the symptoms of PD.
authors.affiliation: Instituto de Bioquímica Médica, Programa de Biologia Estrutural, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-590, Brazil.
authors.forename: Cristian
authors.initials: C
authors.lastname: Follmer
authors.forename: Luciana
authors.initials: L
authors.lastname: Romão
authors.forename: Carla M
authors.initials: CM
authors.lastname: Einsiedler
authors.forename: Thaís C R
authors.initials: TC
authors.lastname: Porto
authors.forename: Flávio Alves
authors.initials: FA
authors.lastname: Lara
authors.forename: Marlos
authors.initials: M
authors.lastname: Moncores
authors.forename: Gilberto
authors.initials: G
authors.lastname: Weissmüller
authors.forename: Hilal A
authors.initials: HA
authors.lastname: Lashuel
authors.forename: Peter
authors.initials: P
authors.lastname: Lansbury
authors.forename: Vivaldo Moura
authors.initials: VM
authors.lastname: Neto
authors.forename: Jerson L
authors.initials: JL
authors.lastname: Silva
authors.forename: Debora
authors.initials: D
authors.lastname: Foguel
mesh_terms: D019943:Amino Acid Substitution; D004298:Dopamine / Q000378:metabolism / Q000494:pharmacology*; D004355:Drug Stability; D014644:Genetic Variation; D006801:Humans; D006874:Hydrostatic Pressure; D066298:In Vitro Techniques; D018625:Microscopy, Atomic Force; D008854:Microscopy, Electron; D046912:Multiprotein Complexes; D009474:Neurons / Q000378:metabolism; D010300:Parkinson Disease / Q000209:etiology / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D014867:Water / Q000737:chemistry; D051844:alpha-Synuclein / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
chemical_list: D046912:Multiprotein Complexes; D011994:Recombinant Proteins; D051844:alpha-Synuclein; D014867:Water; D004298:Dopamine