Whole-transcriptome profiling of cumulus cells from vitrified porcine immature oocytes reveals candidate ceRNA regulatory networks

Background Cumulus cells (CCs) are well known to play a regulatory role in driving meiotic resumption and orchestrating the maturation of porcine oocytes. However, their role in oocyte development under vitrification stress remains unclear. Results In this study, whole-transcriptome sequencing was used to compare the expression differences of circular RNAs (circRNAs), long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and messenger RNAs (mRNAs) in CCs derived from fresh and vitrified porcine cumulus-oocyte complexes (COCs) following in vitro maturation. The results revealed 2,603 differentially expressed (DE) mRNAs (DEmRNAs), 27 DEmiRNAs, 511 DElncRNAs, and 89 DEcircRNAs. Gene ontology analysis of these RNAs or their target genes revealed enrichment in numerous processes, including cytoskeleton organization, cell cycle, phosphorylation, apoptosis, and stress granule assembly. Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed their involvement in pathways, including mitogen-activated protein kinase (MAPK) signaling, cell senescence, oocyte meiosis, actin cytoskeleton regulation, ErbB signaling, and cell cycle. Additionally, a putative ceRNA network was constructed involving 27 lncRNAs, 8 circRNAs, 5 miRNAs, and 49 mRNAs, and miR-9843-3p, miR-425-5p, miR-140-5p, miR-451, and miR-664-5p were identified as potential candidate regulators within this network. Four mRNAs, four miRNAs, four lncRNAs and four circRNAs were screened from the constructed predicted ceRNA network and subjected to qRT-PCR validation. Their expression trends showed high consistency with RNA-seq results, supporting the expression patterns identified by transcriptome sequencing and bioinformatic analyses. Further enrichment analysis of mRNAs involved in the constructed predicted ceRNA network revealed their predominant enrichment in important cellular pathways, including Wnt signaling, Hippo signaling, ErbB signaling, MAPK signaling, and mTOR signaling. Conclusion These findings indicate the impact of vitrification on transcriptional regulation in CCs, which may provide candidate molecular clues for optimizing vitrification technology for porcine COCs.