title: Dopamine induces autophagic cell death and alpha-synuclein increase in human neuroblastoma SH-SY5Y cells.
abstract: Free cytoplasmic dopamine may be involved in the genesis of neuronal degeneration in Parkinson's disease and other such diseases. We used SH-SY5Y human neuroblastoma cells to study the effect of dopamine on cell death, activation of stress-induced pathways, and expression of alpha-synuclein, the characteristic protein accumulated in Lewy bodies. We show that 100 and 500 microM dopamine causes a 40% and 60% decrease of viability, respectively, and triggers autophagy after 24 hr of exposure, characterized by the presence of numerous cytoplasmic vacuoles with inclusions. Dopamine causes mitochondrial aggregation in adherent cells prior to the loss of functionality. Plasma membrane and nucleus also maintain their integrity. Cell viability is protected by the dopamine transporter blocker nomifensine and the antioxidants N-acetylcysteine and ascorbic acid. Dopamine activates the stress-response kinases, SAPK/JNK and p38, but not ERK/MAPK or MEK, and increases alpha-synuclein expression. Both cell viability and the increase in alpha-synuclein expression are prevented by antioxidants; by the specific inhibitors of p38 and SAPK/JNK, SB203580 and SP600125, respectively; and by the inhibitor of autophagy 3-methyladenine. This indicates that oxidative stress, stress-activated kinases, and factors involved in autophagy up-regulate alpha-synuclein content. The results show that nonapoptotic death pathways are triggered by dopamine, leading to autophagy. These findings should be taken into account in the search for strategies to protect dopaminergic neurons from degeneration.
authors.affiliation: Unitat de Bioquímica, Departament de Ciències Fisiològiques II, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Gómez-Santos
authors.forename: Isidre
authors.initials: I
authors.lastname: Ferrer
authors.forename: Antonio F
authors.initials: AF
authors.lastname: Santidrián
authors.forename: Marta
authors.initials: M
authors.lastname: Barrachina
authors.forename: Joan
authors.initials: J
authors.lastname: Gil
authors.forename: Santiago
authors.initials: S
authors.lastname: Ambrosio
mesh_terms: D001343:Autophagy / Q000187:drug effects*; D016923:Cell Death / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D004298:Dopamine / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D016631:Lewy Bodies / Q000473:pathology; D008928:Mitochondria / Q000502:physiology; D048056:Mitogen-Activated Protein Kinase 9; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009447:Neuroblastoma; D018384:Oxidative Stress / Q000502:physiology; D051843:Synucleins; D014407:Tumor Cells, Cultured; D051844:alpha-Synuclein; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D009419:Nerve Tissue Proteins; C497604:SNCA protein, human; D051843:Synucleins; D051844:alpha-Synuclein; D048056:Mitogen-Activated Protein Kinase 9; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D004298:Dopamine