Screening and analysis of plasma small extracellular vesicle MiRNAs at various estrous cycle phases of goat.

Small extracellular vesicle are extracellular vesicles secreted by cells into the extracellular space. They contain proteins, lipids, and RNA, which are transferred to neighboring or distant cells through intercellular communication, thereby influencing the recipient cells. Plasma components at different stages of the estrous cycle can affect follicular development, oocyte maturation, and fertilization in animals. To investigate the role of plasma small extracellular vesicle miRNAs in physiological processes such as follicular development, oocyte maturation, and ovulation in goats, we conducted small RNA sequencing on plasma small extracellular vesicle derived from nine samples: three from the estrus phase, three from the post-estrus phase, and three from the interestrus phase, representing different stages of the estrous cycle. We identified 20 differentially expressed miRNAs in plasma small extracellular vesicle between the estrus and post-estrus phases, 11 between the post-estrus and interestrus phases, and 11 between the estrus and interestrus phases. The miRNAs specifically expressed at each estrous cycle stage may serve as biomarkers for diagnosis. GO and KEGG enrichment analyses of the predicted target genes of these miRNAs revealed that they are primarily enriched in pathways related to AMPK, MAPK, calcium signaling, cell adhesion, neurotrophic factors, estrogen signaling, and ovarian steroid synthesis. These findings provide insights into the impact of plasma small extracellular vesicles miRNAs at different stages of the estrous cycle on female animal reproduction.