O papel dos microRNAs exossomais no metabolismo e envelhecimento ovariano usando camundongos como modelo de menopausa

Abstract

The decline in ovarian reserve leads to menopause and a reduction in serum estrogen levels. MicroRNAs are small non-coding RNAs that can regulate geneexpression, being secreted by cells and transported in the serum via exosomes(EXO). Exosomes are demonstrated as having potential therapeutic effects, with significant potential as drug delivery platforms for disease treatment.However, no study evaluating the effects of estradiol (E2), miRNAs, and EXO injection on mouse fertility had been reported until now. Therefore, in this thesis,our objective was to identify miRNA profiles in serum exosomes of mice inducedinto estrous and treated with E2, as well as to characterize the role of EXO in modulating post-menopausal metabolism.In Article 1, female mice were divided into three groups: Control (CTL), injected with 4-vinylcyclohexene diepoxide (VCD) to induce estrous, and VCD+E2, induced into estrous and supplementedwith E2. In Article 2, mice were divided into CTL and VCD groups, but one VCDgroup received EXO supplementation. These EXOs were extracted from cyclicmice of the same age and injected for 21 days. In both articles, estrous resultedin weight gain compared to CTL.From the miRNA sequencing of exosomes extracted from serum, 402 miRNAs were detected in Article 1 and 355 miRNAsin Article 2. Our results suggest that VCD-induced estrous and E2 replacementimpact the profile of serum exosomal miRNAs. Additionally, miR-200a-3p and miR-200b-3p, regulated in the animals' serum, were also regulated in ovarian tissue. We also conducted exosome characterization and liver tissuesequencing in Article 2. In the VCD+EXO group, a total of 1285 genes were regulated in the liver compared to the VCD group, highlighting significant regulation of EXOs in the hepatic transcriptome. Some pathways were exclusively regulated in EXOs compared to VCD, suggesting a direct effect of EXO treatment, including pathways related to inflammation and tissue repair.Our findings serve as a starting point for using exo-miRs as regulators ofmetabolic health in acyclic women. Analyses showed that ovarian activity can modulate miRNA-mediated epigenetic modifications, and estradiol replacementhas an impact on serum exosomal miRNA profiles. In other words, E2 and EXOmay emerge as potential candidates for the development of new therapies.