Gene expression profiles in mouse cumulus cells derived from in vitro matured oocytes with and without blastocyst formation

Cumulus cells (CCs) are considered as an important source to predict oocyte quality. Despite numerous candidate genes in CCs have been identified for embryonic developmental competence, the results are inconsistent. The next generation RNA-sequencing was used to investigate the transcriptomic differences in CCs from in vitro matured oocytes did or did not develop to blastocyst stage following in vitro fertilization (IVF). In our study, the corresponding mouse oocytes were traced using a single-cell tracking system, and CCs were pooled into groups based on the embryonic developmental outcomes. In vivo matured oocytes with blastocyst development were set as a reference group. The transcriptomic differences in mouse CCs from in vitro maturated oocytes with or without blastocyst formation were tested by RNA-sequencing. Real-time PCR was used to verify the expression levels of those candidate genes. A total of 103 transcripts were significantly up-regulated, and 97 down-regulated, in the CCs with the oocytes developed to blastocyst stage. The bioinformatics study showed that those genes were involved in tube morphogenesis, cell-cell signaling and cell projection formation. Nine genes were selected from the most significantly changed transcripts after comparison with the reference group: Arrb1, Atp2c1, Cdh5, Cntnap1, Mkln1, Lgr4, Rhobtb1, Smc2 and Six2, as the candidate target genes. They were associated with the regulation of G-protein coupled receptors, Wnt and MAPK signaling, actin filaments and cell adhesion. Real-time PCR verified the up-regulation of all 9 genes, and significantly increased of Rhobtb1, Mkln1, Smc2, Arrb1, Atp2c1, Cdh5 and Lgr4. Based on RNA-sequencing, we found the changes in gene transcription of mouse CCs that were critical for the communication between CCs and oocytes. The results could provide novel insights on non-invasively predicting the oocyte quality and improving developmental competence.