Coticchio Giovanni, Ophir Libby, Yung Yuval, Baum Micha, Dal Canto Mariabeatrice, Mignini-Renzini Mario, Brambillasca Fausta, Fadini Rubens, Hourvitz Ariel
Biogenesi Reproductive Medicine Centre, Istituti Clinici Zucchi, Monza, Italy.
Int J Dev Biol. 2017;61(6-7):433-437. doi: 10.1387/ijdb.160364gc.
Differences in cumulus cell gene expression after oocyte maturation in vitro (IVM) or in vivo have been described in previous studies. However, the possible impact of follicle stage on gene expression deregulation during human oocyte IVM remains unknown. Expression of selected genes of interest was compared in cumulus cell of three classes of human cumulus cell-oocyte complexes (COCs): a) COCs derived from human chorionic gonadotropin (hCG)-triggered IVM cycles, collected at the germinal vesicle (GV) stage from mid-sized follicles (4-12 mm) and matured in vitro (IVM-GV); b) COCs derived from hCG-triggered IVM cycles, collected from mid-sized follicles (4-12 mm) and matured in vivo (IVM-MII); c) COCs derived from controlled ovarian stimulation in vitro fertilization (IVF) cycles, collected from large/preovulatory follicles and matured in vivo (IVF-MII). Overall, mRNA levels of the large majority of the 20 genes of different regulative and metabolic pathways subject to analysis were altered in IVM samples compared with in vivo matured COCs. In some cases, follicle size appeared to have a role in determining transcription deregulation. For example, in comparison to the IVF-MII control, the luteinizing hormone receptor was largely overexpressed in both IVM-GV and IVM-MII COCs, therefore irrespective of IVM. However, in other circumstances follicle size and IVM had distinct and opposite impacts on gene expression, as shown by transcription of amphiregulin, which was increased in IVM-MII COCs, but decreased in COCs matured in vitro (IVM-GV) compared with the IVF-MII control. This study confirms and extends previous data on gene expression dysregulation during IVM and indicates that the size of follicles from which immature oocytes are retrieved can be an independent factor of differential transcriptional regulation.
先前的研究已经描述了体外成熟（IVM）或体内成熟的卵母细胞成熟后卵丘细胞基因表达的差异。然而，卵泡阶段对人类卵母细胞IVM过程中基因表达失调的潜在影响仍然未知。比较了三类人类卵丘细胞-卵母细胞复合体（COC）的卵丘细胞中选定的感兴趣基因的表达：a）来自人绒毛膜促性腺激素（hCG）触发的IVM周期的COC，在卵泡期（GV）阶段从中等大小的卵泡（4-12毫米）收集，并在体外成熟（IVM-GV）；b）来自hCG触发的IVM周期的COC，从中等大小的卵泡（4-12毫米）收集，并在体内成熟（IVM-MII）；c）来自体外受精（IVF）周期中控制性卵巢刺激的COC，从大/排卵前卵泡收集，并在体内成熟（IVF-MII）。总体而言，与体内成熟的COC相比，IVM样本中大多数参与分析的20个不同调节和代谢途径的基因的mRNA水平发生了改变。在某些情况下，卵泡大小似乎在决定转录失调方面起作用。例如，与IVF-MII对照相比，促黄体生成素受体在IVM-GV和IVM-MII COC中均大量过表达，因此与IVM无关。然而，在其他情况下，卵泡大小和IVM对基因表达有明显相反的影响，如双调蛋白的转录所示，与IVF-MII对照相比，IVM-MII COC中的双调蛋白转录增加，但在体外成熟的COC（IVM-GV）中减少。这项研究证实并扩展了先前关于IVM过程中基因表达失调的数据，并表明从中获取未成熟卵母细胞的卵泡大小可能是差异转录调节的一个独立因素。
