Dose-dependent transcriptome expression of alcohol on oligodendrocytes

Oligodendrocytes (OLs) are glial cells within the central nervous system (CNS) that produce myelin, which coats neuronal axons and enhances fast propagation of neuronal signals. OLs are known to be severely affected by alcohol in fetal alcohol spectrum disorder (FASD) and alcohol use disorder (AUD). In FASD, oligodendrocyte precursor cells have been reported to be highly affected by any dose of alcohol. In AUD, high doses of alcohol can lead to demyelinating complications such as Wernicke-Korsakoff sybdrome. However, relatively little is known about how alcohol at low and high doses affects mature OLs (mOLs). To better understand the impact of concentration-dependent alcohol exposure on mOLs, we isolated and differentiated immature murine OLs into mOLs and exposed them to a moderate or high concentration of alcohol in vitro. RNA was then isolated from the cultures and sequenced using 3'-Tag RNA sequencing. Differential expression across alcohol concentration and control groups was calculated, which was used for gene set enrichment analysis to identify KEGG and GO terms that were significantly changed as a result of alcohol treatment. We found concentration dependent changes in biological pathways related to cell cycle regulation, translation initiation, integrin signaling, FGF2 signaling, inflammation, and myelination. Further, we found that the moderate and high concentrations of alcohol elicited distinct changes in gene expression, indicating that concentration is a critical factor when determining the effects of alcohol on transcriptomic changes. Overall design: Differentiated oligodendrocytes were grown in culture and exposed to alcohol at two different concentrations across two experiments. In the first, 6 wells each of control (no alcohol) and high concentration (30mM) ethanol-exposed oligodendrocytes were lysed and RNA was extracted for 3'-Tag sequencing. In the second experiment, 6 wells each of control and moderate concentration (10mM) ethanol-exposed oligodendrocytes were lysed and RNA was extracted for 3'-Tag sequencing. The cells were isolated from P5-7 mouse pups and differentiated for three days in culture. On the third day, alcohol was added to the culture and allowed to incubate for an additional three days before cells were lysed.