PURPOSE

We investigated the interactions between mural granulosa cells (MGCs) and cumulus granulosa cells (CGCs) during ovulation after the LH surge.

METHODS

We performed clustering, pseudotime, and interactome analyses utilizing reported single-cell RNA sequencing data of mouse ovary at 6 h after eCG-hCG injection.

RESULTS

Clustering analysis classified granulosa cells into two distinct populations, MGCs and CGCs. Pseudotime analysis divided granulosa cells into before and after the LH surge, and further divided them into two branches, the ovulatory MGCs and the ovulatory CGCs. Interactome analysis was performed to identify the interactions between MGCs and CGCs. Twenty-six interactions were acting from CGCs toward MGCs, involving ovulation and steroidogenesis. Thirty-six interactions were acting from MGCs toward CGCs, involving hyaluronan synthesis. There were 25 bidirectional interactions, involving the EGFR pathway. In addition, we found three novel interactions: Ephrins-Ephs pathway and Wnt-Lrp6 pathway from CGCs to MGCs, associated with steroidogenesis and lipid transport, respectively, and TGF-β-TGFBR1 pathway from MGCs to CGCs, associated with hyaluronan synthesis.

CONCLUSIONS

MGCs and CGCs interact with each other in the preovulatory follicle after the LH surge, and their interactions have roles in corpus luteum formation, oocyte maturation, and follicle rupture.