Characterization and miRNA Profiling of Extracellular Vesicles from Rabbit Oviduct and Uterine Fluids

This study aims to uncover how extracellular vesicles (EVs) influence key reproductive processes by isolating, characterizing, and analyzing the miRNA cargo of these oviductal and uterine fluid-EVs. Small RNA sequencing identified 388 miRNAs in OF-EVs and UF-EVs. However, 4 miRNAs significantly more abundant in OF-EVs, while 17 were significantly more abundant in UF-EVs, indicating potential differences in their roles in embryo-maternal communication. The most abundant miRNAs in both fluids included ocu-miR-148a-3p, ocu-let-7i-5p, and ocu-miR-10b-5p, which are associated with embryo development and implantation. Gene target prediction analysis of the top abundant revealed that miRNAs in OF-EVs regulate key signaling pathways such as MAPK, Hippo, TGF-ß, Ras, PI3K-Akt, and mTOR, while UF-EVs are associated with Hippo, PI3K-Akt, FoxO, endocytosis, and mTOR signaling. These pathways are essential for cell proliferation, differentiation, and immune regulation, crucial for embryo-maternal interactions. Our findings suggest that EVs in rabbit reproductive fluids play a fundamental role in early embryonic development and successful pregnancy. These results provide new insights into reproductive biotechnology and veterinary medicine, with potential applications in improving fertility and embryo viability. Overall design: Characterization, comparison and analysis of the rabbit miRNA cargo of oviductal and uterine fluid extracellular vesicles