Dettleff Phillip, Palomino Jaime, González-Coppia Fabiola, De Los Reyes Monica
School of Veterinary Medicine, Faculty of Agronomy and Natural Systems, Faculty of Biological Sciences and Faculty of Medicine, Pontifical Catholic University of Chile. Santiago, Chile.
School of Veterinary Medicine, Center for Health and Society Research Studies, Bernardo O'Higgins University, Santiago, Chile; Laboratory of Animal Reproduction, Faculty of Veterinary Sciences, University of Chile, Santiago, Chile.
Theriogenology. 2025 Aug;242:117454. doi: 10.1016/j.theriogenology.2025.117454. Epub 2025 Apr 21.
Oocyte maturation is a critical process for successful fertilization and early embryonic development. In this study, we investigated the molecular mechanisms underlying oocyte maturation in dogs by analyzing the transcriptomic profiles of miRNAs and mRNAs in canine cumulus cells (CCs) and oocytes during in vitro maturation (IVM). RNA sequencing identified 285 miRNAs expressed in oocytes and 310 in CCs, with 282 miRNAs shared between the two cell types, highlighting the role of intercellular communication in maintaining miRNA expression equilibrium. Differential expression analysis revealed 222 mRNAs with significant differences between CCs and oocytes, including genes involved in transcriptional regulation and nuclear structure. Enrichment analyses identified pathways such as actin cytoskeleton regulation, mTOR signaling, cAMP signaling, and calcium signaling, all critical to oocyte maturation. Network analysis revealed 643 significant miRNA-mRNA coexpression relationships, suggesting miRNAs play pivotal roles in regulating mRNA expression during oocyte maturation. Notably, key miRNAs such as miR-30b, miR-375, and miR-503 were implicated in regulating genes involved in oocyte maturation pathways, while others like miR-378 and miR-21 aligned with known roles in suppressing cumulus expansion and influencing maturation. The absence of differential miRNA expression between CCs and oocytes suggests the miRNA transfer through gap junctions. These findings provide new insights into the transcriptional and post-transcriptional regulation of oocyte maturation in dogs, offering valuable knowledge to improve reproductive biotechnologies such as in vitro fertilization and embryo development in this species.
卵母细胞成熟是成功受精和早期胚胎发育的关键过程。在本研究中，我们通过分析犬卵丘细胞（CCs）和卵母细胞在体外成熟（IVM）过程中miRNA和mRNA的转录组图谱，研究了犬卵母细胞成熟的分子机制。RNA测序鉴定出卵母细胞中表达285种miRNA，CCs中表达310种miRNA，两种细胞类型共有282种miRNA，突出了细胞间通讯在维持miRNA表达平衡中的作用。差异表达分析揭示了CCs和卵母细胞之间有222种mRNA存在显著差异，包括参与转录调控和核结构的基因。富集分析确定了肌动蛋白细胞骨架调节、mTOR信号传导、cAMP信号传导和钙信号传导等途径，这些对卵母细胞成熟都至关重要。网络分析揭示了643种显著的miRNA-mRNA共表达关系，表明miRNA在卵母细胞成熟过程中调节mRNA表达方面发挥着关键作用。值得注意的是，miR-30b、miR-375和miR-503等关键miRNA参与调节卵母细胞成熟途径中的相关基因，而miR-378和miR-21等其他miRNA与抑制卵丘扩展和影响成熟的已知作用一致。CCs和卵母细胞之间不存在miRNA差异表达表明miRNA通过缝隙连接转移。这些发现为犬卵母细胞成熟的转录和转录后调控提供了新的见解，为改进该物种的体外受精和胚胎发育等生殖生物技术提供了有价值的知识。
