Silva Beatriz Celeiro E, Drzewiecka Ewa Monika, Piotrowska-Tomala Katarzyna, Alpoim-Moreira Joana, Sadowska Agnieszka, Kowalik Magdalena Karolina, Pimenta Jorge, Rebordão Maria Rosa, Ferreira-Dias Graça, Skarzynski Dariusz, Szóstek-Mioduchowska Anna
C.I.I.S.A., Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal.
Institute of Animal Reproduction and Food Research Polish Academy of Sciences, 10-748 Olsztyn, Poland.
Reprod Biol. 2024 Dec;24(4):100962. doi: 10.1016/j.repbio.2024.100962. Epub 2024 Oct 22.
A reduction in myometrial contractile activity can lead to inadequate cleaning of the uterine lumen, resulting in persistent endometritis and potentially endometrosis in mares. Oxytocin (OXT) is a key hormonal regulator of myometrial contraction. While epigenetic regulation of myometrial gene expression has been studied in humans, there is limited information on the expression of DNA methyltransferases (DNMTs) and ten-eleven translocation enzymes (TETs) in the myometrium of mares. This study aimed to evaluate the mRNA transcription of these enzymes and the potential role of DNA methylation in the expression of the OXT receptor (OXTR) gene in the myometrium of mares with endometrosis. Myometrial samples were collected post-mortem during the mid-luteal (n = 23) and follicular (n = 20) phases of the estrous cycle and assessed according to Kenney and Doig endometrial category (I, IIA, IIB, III). mRNA transcription of OXTR, DNMT1, -3A, -3B and TET1, -2, -3 were determined using qPCR. DNA methylation analysis at CpG islands of OXTR exons 1 and 2 was performed using bisulfite pyrosequencing. Myometrial OXTR mRNA transcription and DNA methylation in its promoter region showed no significant differences between categories, although increased methylation was observed at CpG island position 6 in exon 2. DNMT1, TET2, and TET3 mRNA transcription was altered in the equine myometrium depending on the phase of the estrous cycle and the severity of endometrosis (P < 0.05). These findings indicate that DNMTs and TETs were expressed in myometrium in a manner specific to the severity of endometrosis and phases of the estrous cycle, suggesting a potential regulatory role in DNA methylation of myometrial gene expression.
子宫肌层收缩活动的降低会导致子宫腔清理不充分，从而引发母马持续性子宫内膜炎并可能导致子宫内膜异位症。催产素（OXT）是子宫肌层收缩的关键激素调节因子。虽然在人类中已对子宫肌层基因表达的表观遗传调控进行了研究，但关于母马子宫肌层中DNA甲基转移酶（DNMTs）和十一-易位酶（TETs）的表达信息有限。本研究旨在评估这些酶的mRNA转录情况以及DNA甲基化在患有子宫内膜异位症的母马子宫肌层中催产素受体（OXTR）基因表达中的潜在作用。在发情周期的黄体中期（n = 23）和卵泡期（n = 20）进行死后采集子宫肌层样本，并根据Kenney和Doig子宫内膜分类（I、IIA、IIB、III）进行评估。使用qPCR测定OXTR、DNMT1、-3A、-3B和TET1、-2、-3的mRNA转录情况。使用亚硫酸氢盐焦磷酸测序法对OXTR外显子1和2的CpG岛进行DNA甲基化分析。子宫肌层OXTR mRNA转录及其启动子区域的DNA甲基化在各分类之间无显著差异，尽管在外显子2的CpG岛位置6观察到甲基化增加。DNMT1、TET2和TET3的mRNA转录在马的子宫肌层中因发情周期阶段和子宫内膜异位症的严重程度而发生改变（P < 0.05）。这些发现表明，DNMTs和TETs在子宫肌层中的表达方式与子宫内膜异位症的严重程度和发情周期阶段有关，提示其在子宫肌层基因表达的DNA甲基化中可能具有调节作用。
