Approximately48 miRNAs were up-regulatedin the frontal cortex of alcoholics (p < 0.005, FDR < 15%) with a fold change of between 16% and 72% (mean = 27% ± 11%). Interestingly, miRNA down-regulation was not observed at this level of significance. The miRNA microarray contains probes targeting miRNAs for human, mouse, rat, Drosophila, C.elegans, and zebrafish; and, several miRNAs that met our significance cutoff for differential expression were from species other than human. For each of these miRNAs, the sequence of the probe representing the miRNA on the array was compared with all known miRNA sequences in miRBase using BLAST to identify the human equivalent. Where there was a greater than 90% homology in miRNA sequence across species, the human homologs for the miRNAs were used for target prediction. Six of the differentially expressed miRNAs had no homology to any known human miRNA and were not included in subsequent analyses.
