title: Linking alpha-synuclein phosphorylation to reactive oxygen species formation and mitochondrial dysfunction in SH-SY5Y cells.
abstract: Alpha-synuclein (α-syn) is a soluble protein highly enriched in presynaptic terminals of neurons. Accumulation of α-syn as intracellular filamentous aggregates is a pathological feature of sporadic and familial forms of Parkinson's disease (PD). Changes in α-syn post-translational modifications, as well as mitochondrial dysfunction and oxidative stress constitute key pathogenic events of this disorder. Here we assessed the correlation between α-syn phosphorylation at serine 129 (Ser129), the formation of reactive oxygen species (ROS) and mitochondrial dysfunction in SH-SY5Y cells expressing A53T mutant or wild-type (WT) α-syn, exposed to ferrous iron (FeSO4) and rotenone (complex I inhibitor). Under basal conditions, prolonged expression of A53T mutant α-syn altered mitochondria morphology, increased superoxide formation and phosphorylation at Ser129, which was linked to decreased activity of protein phosphatase 2A (PP2A). Exposure to FeSO4 or rotenone enhanced intracellular ROS levels, including superoxide anions, in both types of cells, along with α-syn Ser129 phosphorylation and mitochondrial depolarization. Most of these changes were largely evident in A53T mutant α-syn expressing cells. Overall, the data suggest that stimuli that promote ROS formation and mitochondrial alterations highly correlate with mutant α-syn phosphorylation at Ser129, which may precede cell degeneration in PD.
authors.affiliation: CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
authors.forename: Rita
authors.initials: R
authors.lastname: Perfeito
authors.affiliation: Department of Neurodegeneration and Restorative Research, University Medical Center Goettingen, Goettingen, Germany.
authors.forename: Diana F
authors.initials: DF
authors.lastname: Lázaro
authors.affiliation: Department of Neurodegeneration and Restorative Research, University Medical Center Goettingen, Goettingen, Germany; Cell and Molecular Neuroscience Unit, Instituto de Medicina Molecular, Lisboa, Portugal; Instituto de Fisiologia, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.
authors.forename: Tiago F
authors.initials: TF
authors.lastname: Outeiro
authors.affiliation: CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Faculty of Medicine, University of Coimbra, Coimbra, Portugal. Electronic address: acrego@cnc.uc.pt.
authors.forename: A Cristina
authors.initials: AC
authors.lastname: Rego
mesh_terms: D045744:Cell Line, Tumor; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D018384:Oxidative Stress; D010766:Phosphorylation; D017382:Reactive Oxygen Species / Q000378:metabolism*; D051844:alpha-Synuclein / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species; D051844:alpha-Synuclein
keywords: Alpha-synuclein; Alpha-synuclein Ser129 phosphorylation; Mitochondrial dysfunction; Oxidative stress; Parkinson's disease; Protein phosphatase 2A