Acute ethanol challenge differentially regulates expression of Growth Factors and miRNA expression profile of whole tissue of the dorsal hippocampus

Acute ethanol exposure produces rapid alterations in neuroimmune gene expression that are both time- and cytokine-dependent. Interestingly, adolescent rats, who often consume binge-like quantities of alcohol, displayed reduced neuroimmune responses to acute ethanol challenge. However, it is not known whether growth factors, a related group of signaling factors, respond to ethanol similarly in adults and adolescents. To test this, adolescent and adult Sprague Dawley rats of both sexes were injected with either ethanol or saline, and brains were harvested 3 hr post-injection for assessment of growth factor, cytokine, or miRNA expression. RNASeq revealed a rapid suppression of 12 miRNA species. Of the miRNA affected by ethanol, the majority were related to inflammation or cell survival and proliferation factors, including FGF2, MAPK, NFκB, and VEGF. Adult male Sprague Dawley rats (n=8 per group, N= 16) were injected with ethanol (4 g/kg) in early adulthood (P70-80) and euthanized 3 hr later. Brain tissue sections were submitted to RNAseq including enrichment for miRNA in the sample similar to that used previously (Ignacio, Mooney, & Middleton, 2014). For each rat, 1 μg of total RNA was purified using the TruSeq Small RNA Sample Prep kit (Illumina, San Diego, CA, USA) and subsequent gel purification for small (20-30 nt) RNA species. Libraries were indexed and multiplexed in sets of 8 (6 sets total) prior to sequencing (single-end, 37 cycles) using Reagent Kit v3 reagents on a MiSeq Benchtop Sequencer (Illumina, San Diego, CA, USA).