Transcriptome profiling of microglia from mouse PFC shows altered expression of coordinately regulated groups of genes after recurring periods of voluntary ethanol consumption (McCarthy et al., 2017b). This study highlights a possible role for TGF-β, and its interaction with sialic acid-binding Ig-like lectin H (Siglec-H), in ethanol-induced immune signaling in the brain. Despite the gene network alterations, IBA1 immunohistochemistry indicates no change in microglia activation 0 or 24 h after ethanol removal (McCarthy et al., 2017c). Hippocampal microglia activation after binge ethanol drinking is also not associated with increased inflammatory markers, suggesting a beneficial or homeostatic role for microglia after ethanol exposure (Marshall et al., 2013; McClain et al., 2011). Although ethanol alters microglia activation, how the functional states vary across brain regions and stages of alcohol dependence remains to be determined.
