Rescue of alpha-synuclein toxicity in a yeast model of Parkinson's disease

Cellular toxicities of alpha-synuclein manifest through multiple pathways, including mitochondrial dysfunction and the inhibition of vesicle trafficking. Several defects can be ameliorated by small molecule suppressors that antagonize toxicity in model systems ranging from yeast to neurons. Connections between these distinct pathologies may be central to Parkinson Disease and to therapeutic strategies. First, yeast cultures with 1 or 2 copies of human alpha-synuclein were profiled during a time series of 0 to 6 hours. Second, to investigate any potential rescue of alpha-synuclein toxicity, one of a series of six compounds: compound 1 ((4-(3-iodophenyl)-3,4-dihydrobenzo[h]quinolin-2(1H)-one); compound 2 (4-(3-bromophenyl)-3,4-dihydrobenzo[h]quinolin-2(1H)-one); compound 3 (4-(5-bromo-2-fluorophenyl)-6,7-dimethyl-3,4-dihydro-2(1H)-quinolinone); compound 4 (4-(3-bromo-4-fluorophenyl)-6,7-dimethyl-3,4-dihydro-2(1H)-quinolinone); compound 5 (4-(4-ethyl)-6,7-dimethyl-3,4-dihydro-2(1H)-quinolinone); compound 6 ((4R)-6-bromo-4-(4-ethylphenyl)-3,4-dihydrobenzo[h]quinolin-2(1H)-one); was introduced and the expression profile assayed at 4 hours. For the time series, at each time point (0, 2, 4, 6 hours) three yeast samples (2-copy alpha-synuclein; 1-copy alpha-synuclein; empty vector control) were each prepared and hybridized in all three combinations (2-copy vs control; 1-copy vs control; 2-copy vs 1-copy) for that time point. For the drug treatment, three yeast samples were grown each with 2-copy alpha-synuclein or an empty vector control, with or without one of six compounds: compound 1 ((4-(3-iodophenyl)-3,4-dihydrobenzo[h]quinolin-2(1H)-one); compound 2 (4-(3-bromophenyl)-3,4-dihydrobenzo[h]quinolin-2(1H)-one); compound 3 (4-(5-bromo-2-fluorophenyl)-6,7-dimethyl-3,4-dihydro-2(1H)-quinolinone); compound 4 (4-(3-bromo-4-fluorophenyl)-6,7-dimethyl-3,4-dihydro-2(1H)-quinolinone); compound 5 (4-(4-ethyl)-6,7-dimethyl-3,4-dihydro-2(1H)-quinolinone); compound 6 ((4R)-6-bromo-4-(4-ethylphenyl)-3,4-dihydrobenzo[h]quinolin-2(1H)-one). 2-color hybridization compared (a) 2-copy vs 2-copy+compound, (b) vector vs vector+compound, or (c) 2-copy+compound vs vector+compound.