Transcriptome analysis of a chronic in vitro model of Parkinsonism

SK-N-MC cells were grown in three different conditions: media + vehicle (EtOH), media + a sublethal dose (5 nM) of rotenone, and media + a slightly toxic dose (50 nM) of rotenone. Gene expression was examined at 1 and 4 weeks of rotenone treatment. Three experiments were performed, each lasting 1 and 4 weeks. For each experiment, 5 separate dishes of vehicle-treated, and rotenone-treated cells were harvested at 1 and 4 weeks (30 independent samples at each time point) and pooled into 3 samples (vehicle treated,and rotenone treated with 5 nM and 50 nM) at each time point for a total of 18 individual samples from all thre experiments. Total RNA isolated from each of the 18 individual samples was used to prepared labeled cRNA and hybridized to one Genechip (Affymetrix) Human Genome array HG-U133A at the UCLA microarray core facility (http://microarray.genetics.ucla.edu/). After QC check, the data was normalized and used to assess expression indexes and fold changes (FC > 2.0, compared to vehicle-treated controls) using the model-based expression indexes (MBEI) method implemented in dCHIP, ( http://biosun1.harvard.edu/complab/dchip/), and the Signifiance Analysis of Microarrays (SAM) software for multiple test corrections. Enrichment analysis was performed by the functional annotation tools implemented in DAVID ( http://david.abcc.ncifcrf.gov), to ascertain sets of rotenone DRGs that are enriched in certain biological annotations.