Six R, Benedetti C, Fan Y, Guan X, Gansemans Y, Hedia Mohamed, Bogado Pascottini O, Pavani K C, Van Nieuwerburgh F, Deforce D, Smits K, Van Soom A, Peelman L
Department of Veterinary and Biosciences, Ghent University, Merelbeke, Belgium.
Department of Internal Medicine, Reproduction and Population Medicine, Ghent University, Merelbeke, Belgium.
Front Cell Dev Biol. 2024 Jul 11;12:1404675. doi: 10.3389/fcell.2024.1404675. eCollection 2024.
MicroRNAs (miRNA) are important regulators of oocyte maturation, playing a key role in modulating gene expression both in a temporal- and spatial-specific manner. These small non-coding RNAs are involved in important processes during oocyte maturation, acting as messengers between the oocyte and its surrounding cumulus cells. Despite its significance, the bidirectional communication mechanism is still unknown. To test miRNA communication between oocyte and surrounding cumulus cells through the gap junctions the gap junctions were either blocked with carbenoxolone or not. MiRNA sequencing of oocytes at 1, 6, and 22 h of maturation was then performed. Among the differentially expressed miRNAs, bta-miR-21-5p, a regulator of cumulus cell viability and oocyte maturation, was the only previously known miRNA. Furthermore, by labeling a bta-miR-21-5p mimic with FAM, crossing of this miRNA through the gap junctions within the cumulus-oocyte complex could be visualized and internalization in the oocyte was confirmed by RT-qPCR. In conclusion, this study provides, for the first time, evidence that miRNA communication within the bovine cumulus-oocyte complex is enabled through the gap junctional network.
微小RNA（miRNA）是卵母细胞成熟的重要调节因子，在以时间和空间特异性方式调节基因表达方面发挥关键作用。这些小的非编码RNA参与卵母细胞成熟过程中的重要进程，充当卵母细胞与其周围卵丘细胞之间的信使。尽管其具有重要意义，但其双向通讯机制仍不清楚。为了测试卵母细胞与周围卵丘细胞之间通过缝隙连接的miRNA通讯，用羧苄青霉素阻断或不阻断缝隙连接。然后对成熟1小时、6小时和22小时的卵母细胞进行miRNA测序。在差异表达的miRNA中，bta-miR-21-5p是唯一已知的miRNA，它是卵丘细胞活力和卵母细胞成熟的调节因子。此外，通过用FAM标记bta-miR-21-5p模拟物，可以观察到这种miRNA穿过卵丘-卵母细胞复合体中的缝隙连接，并且通过RT-qPCR证实其在卵母细胞中的内化。总之，本研究首次提供了证据，表明牛卵丘-卵母细胞复合体中的miRNA通讯是通过缝隙连接网络实现的。
