Differential cytotoxicity of dopamine and H2O2 in a human neuroblastoma divided cell line transfected with alpha-synuclein and its familial Parkinson's disease-linked mutants.
alpha-Synuclein accumulates in Lewy bodies and two missense mutations, A30P and A53T, have been linked to familial Parkinson's disease. Neither the normal function of alpha-synuclein nor the pathomechanism of alpha-synuclein-induced neuropathy are known. SK-N-MC neuroblastoma cells were transiently transfected with either wt alpha-synuclein, or its mutants, and their abilities to protect against oxidative stress were assessed. At low expression levels (1 microg cDNA/10(5) cells), all three synuclein variants were devoid of any effect on dopamine-induced cytotoxicity and nitrite production, whereas at higher expression (5 microg cDNA/10(5) cells), the variants enhanced dopamine-mediated effects. Low levels of wt alpha-synuclein blocked H(2)O(2)-induced cytotoxicity and nitrite production, a protective effect that was partly decreased upon higher expression. Both A30P and A53T increased in a dose-dependent manner H(2)O(2)-induced nitrite production and cell death. These results show an absence of protective effects for the A30P/A53T mutants, and a differential cytoprotective role of alpha-synuclein against oxidants, which varies according to expression levels.
Wersinger
Christophe
C
Department of Pediatrics, Georgetown University, Washington, DC 20007, USA.
Sidhu
Anita
A
D015153:Blotting, Western; D016923:Cell Death; D004298:Dopamine / Q000009:adverse effects*; D006801:Humans; D006861:Hydrogen Peroxide / Q000009:adverse effects*; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism*; D009447:Neuroblastoma; D009573:Nitrites / Q000378:metabolism; D010300:Parkinson Disease / Q000235:genetics; D051843:Synucleins; D014162:Transfection; D014407:Tumor Cells, Cultured; D051844:alpha-Synuclein
D009419:Nerve Tissue Proteins; D009573:Nitrites; C497604:SNCA protein, human; D051843:Synucleins; D051844:alpha-Synuclein; D006861:Hydrogen Peroxide; D004298:Dopamine