In addition to identification of genes altered by alcohol use, studies have been carried out in rodent [45–48] and human samples to identify gene expression patterns that correlate with alcohol use or preference [49–52]. A comparative network analysis of RNAseq data from rats bred for either high (SHR) or low (BN-LX) alcohol preference, and by including correlation to phenotypic data from a recombinant inbred population, allowed identification of candidate genes associated with alcohol consumption [47], many of which were known to be expressed in microglia (or astrocytes). Analysis of RNA from brain regions of alcoholic compared to non-alcoholic patients have identified patterns of gene expression that discriminate between groups [51, 52]. In the nucleus accumbens of patients with alcohol dependency, over 4500 transcripts were identified as being differentially expressed, which could be clustered into 24 mRNA co-expression networks of which 6 were significantly correlated with dependency [52] and 4 were enriched for glial transcripts. However, in these cases, it is not known if expression changes were direct consequences of alcohol, or secondary to alcohol-induced damage.
