Sex-specific dysregulation of cardiac-enriched microRNAs with age in Drosophila melanogaster

Abstract

Dysregulation of cardiac-enriched microRNA (miRNA) expression is linked to age-associated cardiovascular diseases (CVDs). However, the sex-specificity and age at which dysregulation occurs remain unclear. Given the conserved nature of miRNAs and short lifespan of Drosophila melanogaster (fruit flies), we investigated age-related changes in the expression of cardiac enriched miRNAs (miR-1, -9, -34a, and -133, target miRNAs) and their impact on the cardiac tube in male and female flies. Cardiac tube tissues were collected from male and female flies (n = 5/group) at 7-day intervals from day 7 to day 70. miRNAs and predicted target mRNA gene (KCNQ, MRTF, and CCN) expression were quantified by RT-qPCR (n = 4–6/group). Myofibril diameter was assessed by Masson’s trichrome staining (n = 4–6) to determine the structural effects of hypertrophic miR-9. In females, miR-1 was downregulated with age (P ≤ 0.0001), whereas in males, miR-9 (P ≤ 0.0001) and miR-34a (P = 0.0017) were downregulated. Interestingly, miR-133 was downregulated in both sexes (P ≤ 0.0001). In males, MRTF (miR-9 target) and CCN (miR-133 target) expression increased with age (P = 0.016 and P = 0.013, respectively), whereas in females, KCNQ (miR-1 target) and CCN expression decreased (P = 0.03 and P = 0.002, respectively). Myofibril thickness significantly increased with age in both sexes (P < 0.0001). miR-9 downregulation may contribute to this effect in males, whereas the mechanism in females remains unclear. This study provides novel insights into sex-specific miRNA dysregulation in cardiac aging, emphasizing the need to consider sex differences in miRNA-mediated cardiovascular aging and the potential of miRNAs as diagnostic tools in age-related CVDs.