miRNA profiling of granulosa cell‐derived exosomes reveals their role in promoting follicle development

Abstract To explore whether granulosa cell (GC)‐derived exosomes (GC‐Exos) and follicular fluid‐derived exosomes (FF‐Exos) have functional similarities in follicle development and to establish relevant experiments to validate whether GC‐Exos could serve as a potential substitute for follicular fluid‐derived exosomes to improve folliculogenesis. GC‐Exos were characterized. MicroRNA (miRNA) profiles of exosomes from human GCs and follicular fluid were analyzed in depth. The signature was associated with folliculogenesis, such as phosphatidylinositol 3 kinases‐protein kinase B signal pathway, mammalian target of rapamycin signal pathway, mitogen‐activated protein kinase signal pathway, Wnt signal pathway, and cyclic adenosine monophosphate signal pathway. A total of five prominent miRNAs were found to regulate the above five signaling pathways. These miRNAs include miRNA‐486‐5p, miRNA‐10b‐5p, miRNA‐100‐5p, miRNA‐99a‐5p, and miRNA‐21‐5p. The exosomes from GCs and follicular fluid were investigated to explore the effect on folliculogenesis by injecting exosomes into older mice. The proportion of follicles at each stage is counted to help us understand folliculogenesis. Exosomes derived from GCs were isolated successfully. miRNA profiles demonstrated a remarkable overlap between the miRNA profiles of FF‐Exos and GC‐Exos. The shared miRNA signature exhibited a positive influence on follicle development and activation. Furthermore, exosomes derived from GCs and follicular fluid promoted folliculogenesis in older female mice. Exosomes derived from GCs had similar miRNA profiles and follicle‐promoting functions as follicular fluid exosomes. Consequently, GC‐Exos are promising for replacing FF‐Exos and developing new commercial reagents to improve female fertility.