We observed a modestly significant interaction between alcohol treatment and iPSC donor status for GABRD mRNA with a 24% increase in RNA for AD subjects but no change for CTLs. Prior reports have demonstrated an increase in GABRD expression in the periaqueductal gray matter and dorsal raphe nucleus of alcohol preferring rats following alcohol exposure (McClintick et al. 2015, McClintick et al. 2016), while studies using non-preferring rats found no change in expression (Devaud et al. 1995, Petrie et al. 2001). Expression of GABRD mRNA was lower in the orbitofrontal cortex and caudate nucleus, but not in the hippocampus, amygdala, or putamen of post mortem brain samples from ADs compared to CTLs (Jin et al. 2012, Bhandage et al. 2014, Jin et al. 2014). This prior work, taken together with our finding that 21-day alcohol exposure increased levels of GABRD mRNA in AD neural cell lines, suggests that the regulation of the δ subunit may be relevant to the pathophysiology of alcohol use disorder. Because iPSCs reflect the donor subject’s genetic background, we may have seen an increase in GABRD
