title: Dopamine auto-oxidation aggravates non-apoptotic cell death induced by over-expression of human A53T mutant alpha-synuclein in dopaminergic PC12 cells.
abstract: In this study, we demonstrated that transient transfection and over-expression of human mutant A53T alpha-synuclein (alpha-syn) could induce expression level- and time-dependent, non-apoptotic cell death in PC12 cells, while wild-type and mutant A30P alpha-syn could not. The non-apoptotic cell death induced by over-expression of A53T alpha-syn in PC12 cells was found to be dopamine (DA) related. It could be alleviated by nerve growth factor but not by chemicals that abrogate endoplasmic reticulum stress. Furthermore, PC12 cell death could be alleviated by N-acetyl-cysteine (NAC) as well as by L-cysteine; but not by cell permeable tyrosinase inhibitors. NAC could prevent DA auto-oxidation and tyrosinase-catalyzed DA oxidation, whereas L-cysteine could potently abrogate DA auto-oxidation but could not prevent tyrosinase-catalyzed DA oxidation. Both NAC and L-cysteine could increase the reduced and total GSH levels, and concurrently decrease the oxidized GSH level in PC12 cells. On the other hand, over-expression of human mutant A53T alpha-syn could decrease the reduced and total GSH levels, and increase the oxidized GSH level in the cells. Taken together, we concluded that auto-oxidation of endogenous DA aggravates non-apoptotic cell death induced by over-expression of human mutant A53T alpha-syn in PC12 cells.
authors.affiliation: Department of Biological Science, National University of Singapore, Singapore, Singapore.
authors.forename: Zhi Dong
authors.initials: ZD
authors.lastname: Zhou
authors.forename: Sze Yen
authors.initials: SY
authors.lastname: Kerk
authors.forename: Gao Gao
authors.initials: GG
authors.lastname: Xiong
authors.forename: Tit Meng
authors.initials: TM
authors.lastname: Lim
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D001562:Benzimidazoles; D016923:Cell Death / Q000502:physiology*; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D016166:Free Radical Scavengers / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors; D009154:Mutation; D020932:Nerve Growth Factor / Q000494:pharmacology; D010084:Oxidation-Reduction; D016716:PC12 Cells; D051381:Rats; D013778:Tetrazolium Salts; D013844:Thiazoles; D014162:Transfection; D051844:alpha-Synuclein / Q000096:biosynthesis* / Q000235:genetics*
chemical_list: D001562:Benzimidazoles; D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; D016166:Free Radical Scavengers; D013778:Tetrazolium Salts; D013844:Thiazoles; D051844:alpha-Synuclein; D020932:Nerve Growth Factor; D014442:Monophenol Monooxygenase; C022616:thiazolyl blue; D005978:Glutathione; D003545:Cysteine; C017807:bisbenzimide ethoxide trihydrochloride; D004298:Dopamine; D000111:Acetylcysteine