Extracellular vesicles from cyclic mice modulate liver transcriptome in estroupause mice independent of age.

Extracellular vesicles (EVs) of different sizes are secreted by cells and may contain microRNAs (miRNAs) among its cargo. These miRNAs in EVs can induce changes in gene expression and function of recipient cells. In different cells EVs content can change with age and physiological state affecting tissue function. Based on this, the aim of this study was to characterize the miRNA content and role of small EVs (sEVs) from cyclic female mice in the modulation of liver transcriptome in estropausal mice. Two-month-old female mice were induced to estropause using 4-vinylcyclohexene diepoxide (VCD). At six months of age, VCD-treated mice were divided into placebo group (VCD) and sEVs treated group (VCD + sEVs), which received 10 injections at 3-day intervals of sEVs isolated from serum of donor cyclic female mice. A group of cyclic mice also received placebo injection and served as controls (CTL). sEVs injection in mice undergoing estropause had no effect on body mass, insulin sensitivity or organ weight. We observed ten miRNAs differentially regulated in serum sEVs of VCD compared to CTL mice. In the liver we observed 931 genes differentially expressed in VCD + sEVs compared to VCD mice. Interestingly, eight pathways were up-regulated in liver by VCD treatment and down-regulated by sEVs treatment, indicating that sEVs from cyclic mice can reverse changes promoted by estropause in liver. The expression of Cyp4a12a, which is male-specific, was elevated in VCD females but not normalized by sEVs treatment. Our findings indicate that miRNA content in sEVs is regulated by estropause in mice independent of age. Additionally, treatment of estropausal mice with sEVs from cyclic mice can partially reverse changes in the liver transcriptome.