Sex-specific effects of social defeat stress on miRNA expression in the anterior BNST

•Social defeat stress induces sex-specific miRNA expression patterns in the BNST.•There is more upregulation of miRNAs in stressed females and more downregulation in males.•Let-7a, let-7f, and miR-181a-5p expression is increased by social defeat stress in female but not male mice. Women are more likely to suffer from stress-related affective disorders than men, but the underlying mechanisms of sex differences remain unclear. Previous works show that microRNA (miRNA) profiles are altered in stressed animals and patients with depression and anxiety disorders. In this study, we investigated how miRNA expression in the anterior bed nucleus of stria terminalis (BNST) was affected by social defeat stress in female and male California mice (Peromyscus californicus). We performed sequencing to identify miRNA transcripts in the whole brain and anterior BNST followed by qPCR analysis to compare miRNA expression between control and stressed animals. The results showed that social defeat stress induced sex-specific miRNA expression changes in the anterior BNST. Let-7a, let-7f and miR-181a-5p were upregulated in stressed female but not male mice. Our study provided evidence that social stress produces distinct molecular responses in the BNST of males and females.