limited studies in rodent and cell-based models, and even fewer studies of genome-wide miRNA expression in AD postmortem brain tissue [19–23]. One such study on the PFC of AD subjects identified 35 upregulated miRNAs, which are known to target mRNAs that function in apoptosis, cell adhesion, cell cycling, signaling, and neuronal development [20]. Another recent study profiled mRNAs and miRNAs in the PFC of rats following chronic exposure to alcohol, where mRNAs with functions in neurotransmission, axonal guidance, neuroadaptation, and neurotransmitter signaling were found to be differentially expressed [24]. While the specific relationship between miRNA and mRNA associated with AD is difficult to ascertain, due to the complexity of the transcriptome in AD, several miRNA:mRNA interactions have been experimentally validated [25–28]. Combined genomic profiling of miRNA and mRNA in human NAc has not been conducted, despite the well-established role of NAc in the mesocorticolimbic pathway central to the rewarding properties of alcohol and other drugs of abuse.
