This study tested the hypothesis that oocyte-derived paracrine factors (ODPFs) regulate miRNA expression in mouse granulosa cells.  mmu-miR-322-5p (miR-322) was expressed at higher levels in mural granulosa cells (MGCs) than in cumulus cells of Graafian follicles.  Expression levels of miR-322 were decreased when cumulus cells or MGCs were co-cultured with oocytes denuded of their cumulus cells.  Inhibition of SMAD2/3 signaling by SB431542 increased the miR-322 expression by cumulus-oocyte complexes (COCs).  Moreover, cumulus cells of Bmp15-/-/Gdf9+/- (double-mutant) mice exhibited higher miR-322 expression than those of wild-type mice.  Together, these results show that ODPFs suppress expression of miR-322 in cumulus cells.  Gene ontology analysis of putative miR-322 targets whose expression was detected in MGCs with RNA-sequencing suggested that multiple biological processes are affected by miR-322 in MGCs.  These results demonstrate that ODPFs regulate miRNA expression in granulosa cells and that this regulation may participate in the differential control of cumulus cell versus MGC functions.  Therefore, the ODPF-mediated regulation of cumulus cells takes place at both transcriptional and post-transcriptional levels. SOURCE: Takaho,A.,Endo (takaho.endo@riken.jp) - Laboratory for Integrative Genomics RIKEN

Pluto Bioinformatics

GSE80326: Mouse oocytes suppress mir-322-5p expression in ovarian granulosa cells