Systematic meta-analysis and replication of genome-wide expression studies of Parkinson's disease: 3

Systematic meta-analysis and replication of genome-wide expression studies identifies molecular pathways of Parkinson's disease. Analysis of substantia nigrae from postmortem brains of 6 patients with Parkinson's disease (PD). Results provide insight into the molecular processes perturbed in the PD substantia nigra. Substantia nigra samples from 6 PD and 5 control subjects were obtained. At autopsy, brain hemispheres were frozen in liquid nitrogen and stored at -80C in the Kathleen Price Bryan Brain Bank in the Alzheimer's Disease Research Center at Duke University. Using the RNAgents kit (Promega, Madison, Wis), RNA was extracted from SN and adjacent midbrain tissues. Double-stranded complementary DNA was made with a biotinylated T7(dT)-24 primer. Twenty micrograms of biotinylated complementary RNA was fragmented and hybridized to Affymetrix human genome U133A microarrays. The Affymetrix .CEL files were normalized to "all probe sets" in a standardized matter, and scaled to 100 by the MAS5 algorithm implemented in the Bioconductor package.