Circulating MicroRNAs in Extracellular Vesicles as Potential Biomarkers of Alcohol-Induced Neuroinflammation in Adolescence: Gender Differences

Current studies evidence the role of miRNAs in extracellular vesicles (EVs) as key regulators of pathological processes, including neuroinflammation and neurodegeneration. As EVs can cross the blood-brain barrier, and EV miRNAs are very stable in peripheral circulation, we evaluated the potential gender differences in inflammatory-regulated miRNAs levels in human and murine plasma EVs derived from alcohol-intoxicated female and male adolescents, and whether these miRNAs could be used as biomarkers of neuroinflammation. We demonstrated that while alcohol intoxication lowers anti-inflammatory miRNA (mir-146a-5p, mir-21-5p, mir-182-5p) levels in plasma EVs from human and mice female adolescents, these EV miRNAs increased in males. In mice brain cortices, ethanol treatment lowers mir-146a-5p and mir-21-5p levels, while triggering a higher expression of inflammatory target genes (Traf6, Stat3, and Camk2a) in adolescent female mice. These results indicate, for the first time, that female and male adolescents differ as regards the ethanol effects associated with the inflammatory-related plasma miRNAs EVs profile, and suggest that female adolescents are more vulnerable than males to the inflammatory effects of binge alcohol drinking. These findings also support the view that circulating miRNAs in EVs could be useful biomarkers for screening ethanol-induced neuroinflammation and brain damage in adolescence.