Age and sex differences in microRNAs expression during the process of thymus aging

Abstract

The gender-biased thymus involution and the importance of microRNAs (miRNAs, miRs) expression in modulating the thymus development have been reported in many studies. However, how males and females differ in so many ways in thymus involution remains unclear. To address this question, we investigated the miRNA expression profiles in both untreated 3- A nd 12-month-old female and male mice thymuses. The results showed that 7 and 18 miRNAs were defined as the sex- A nd age-specific miRNAs, respectively. The expression of miR-181c-5p, miR-20b-5p, miR-98b-5p, miR-329-3p, miR-341-5p, and miR-2137 showed significant age-difference in mice thymus by quantitative polymerase chain reaction. High expression levels of miR-2137 were detected in mice thymic epithelial cells and gradually increased during the process of thymus aging. MiR-27b-3p and miR-378a-3p of the female-biased miRNAs were confirmed as the sex- A nd estrogen-responsive miRNAs in mice thymus in vivo. Their potential target genes and the pathway were identified by the online software. Possible regulation roles of sex- A nd age-specific miRNA expression during the process of thymus aging were discussed. Our results suggested that these miRNAs may be potential biomarkers for the study of sex- A nd age-specific thymus aging and involution.