In our study, the average change in the 313 Alc-DEs was 16%, ranging from a 50% decrease to a 72% increase. While modest, these changes are consistent with those reported for microglial transcripts in other studies. In enriched microglia isolated from CTX of alcohol-fed rats [24], the majority of DEs had expression changes between log2 of 0.125 (9%) and 0.375 (30%); changes for the total cortical homogenates were somewhat greater, ranging from log2 of 0.10 (7%) to about 0.5 (50%). In a study of microRNAs, the analysis for DEs used cutoff thresholds of 5% [23], and in a study of synaptosomal transcripts [21], the majority of transcripts showed fold changes on the order of 20% or less. These changes are consistent with reports that modest differences in alcohol-induced gene expression are common for CNS [44]. These observations suggest that modest changes in a set of functionally related mRNAs (and associated proteins) can exert as significant an effect as does a robust change in expression of a single transcript.
