Comparison of MicroRNA Profiles in Extracellular Vesicles from Small and Large Goat Follicular Fluid

Simple Summary: Ovarian follicular development is associated with ovulation and is further related to litter size in goats. Extracellular vesicles (EVs) derived from miRNAs within follicular fluid undergo dynamic changes, and, together with follicle growth, may be considered as potential regulators of follicular development. However, the function and changes in EVs remain ambiguous. Here, we identified miRNA changes in EVs from small to large goat follicular fluid. Using bioinformatics tools, we demonstrated the existence of differentially expressed miRNAs in EVs from follicles of different sizes that are responsible for an altered biological effect. This study contributes to a better understanding of follicular development in goats. Extracellular vesicles (EVs), which exist in the follicular fluid of ruminant ovaries, are considered as cargo carriers for the transfer of biomolecules to recipient cells. However, the functions and changes in EVs in antral follicles remain ambiguous. In the present study, we isolated and characterized EVs from goat follicular fluid by means of differential ultracentrifugation and Western blotting of marker proteins. Bioinformatics tools were used to detect miRNA expression levels in EVs. Different miRNA expression patterns of EVs exist in small to large follicles. Thirteen differentially expressed miRNAs (seven upregulated and six downregulated) were identified and used for analysis. A total of 1948 predicted target genes of 13 miRNAs were mapped to signaling pathways, and three significantly enriched pathways (FoxO, MAPK, and PI3K-AKT signaling pathways) were involved in follicular development, as revealed by KEGG enrichment analysis. Our findings suggest that EVs in follicular fluid play biofunctional roles during follicular development in goats.