Using miRNA microarray technology, their study found a statistically significant inverse correlation between levels of multiple miRNAs of the miR-449/34 family and ACE scores of Caucasian males. Remarkably, members of the same sperm miRNA family are also reduced in mice exposed to CSI stress. Thus, future studies should be designed to directly test whether reduced levels of these miRNAs could be used as unbiased indicators of current and/or early life exposure to severe stress. Moreover, after mating stressed male mice, these sperm miRNA reductions persist in both early embryos through at least the morula stage and in sperm of males derived from them, suggesting these miRNA changes contribute to transmission of stress phenotypes across generations. Since offspring of men exposed to early life trauma have elevated risks for psychological disorders, these findings raise the possibility that a portion of this risk may be derived from epigenetic regulation of these sperm miRNAs.
a qPCR analysis of miR-449a, miR-449b-5p, miR-34b-3p, miR-34c-5p, miR-152-3p, and miR-375-3p in sperm RNA from low ACE group (score 0–1, n = 5) vs. high ACE group (score >4, n = 5). Wilcoxon rank-sum test *P < 0.05, **P < 0.01. Data represented as mean ± SEM. b–c Correlation plot comparing relative expression of miR-449a to miR-449b (b) and miR-34b to miR-34c (c) for individual samples fitted with single-variable linear regression. n = 10, r = Spearman’s coefficient with exact p value listed. Each point represents an individual sample