Mahajan Vishakha, Osavlyuk Diana, Logan Philip C, Amirapu Satya, Ponnampalam Anna P
The Liggins Institute, The University of Auckland, Auckland, New Zealand.
Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
Reproduction. 2020 Aug;160(2):247-257. doi: 10.1530/REP-19-0562.
DNA methyltransferases (DNMTs) and ten-eleven translocation proteins (TETs) facilitate methylation and hydroxymethylation of DNA, respectively. DNMTs are widely studied with conflicting results on their regulation in the endometrium. While the role of TETs in the endometrium remains relatively unexplored. Deregulated expression of TETs and DNMTs are associated with endometrial pathologies. The aim of this study is to characterize the temporal TET expression in endometrium and to determine the hormonal regulation of TETs in comparison to DNMTs. mRNA expressions were quantified by real-time PCR in endometrial tissues from cycling women and localization was determined by immunohistochemistry. Hormonal regulation was investigated in endometrial epithelial and stromal cell lines following a 24 and 48 h treatment cycle. TET1 and 3 mRNA expressions were significantly upregulated in the mid-secretory phase. TET protein expression was ubiquitous in endometrial epithelium throughout the menstrual cycle except during the late-secretory phase, while stromal staining was scattered. TET1 mRNA was significantly upregulated in response to estrogen in stromal cells. Transcriptions of all three TETs were induced in response to progesterone treatment in epithelial cells. Only DNMT3b in epithelial cells and DNMT1 in stromal cells were significantly upregulated upon 24-h estrogen exposure following a significant decrease of DNMT1 when treated with 24 h of estrogen and progesterone. This study suggests that TETs are expressed in a cell-specific, dynamic manner in the endometrium and are responsive to steroid hormones. Investigating the role of TETs individually and with respect to DNMTs, will help to elucidate gene regulatory mechanisms in endometrial biology and pathologies.
DNA甲基转移酶（DNMTs）和10-11易位蛋白（TETs）分别促进DNA的甲基化和羟甲基化。人们对DNMTs进行了广泛研究，但其在子宫内膜中的调节作用结果相互矛盾。而TETs在子宫内膜中的作用仍相对未被探索。TETs和DNMTs的表达失调与子宫内膜病变有关。本研究的目的是描述TETs在子宫内膜中的时间表达特征，并确定与DNMTs相比TETs的激素调节情况。通过实时PCR对周期中女性子宫内膜组织中的mRNA表达进行定量，并通过免疫组织化学确定定位。在24小时和48小时的处理周期后，对子宫内膜上皮和基质细胞系进行激素调节研究。TET1和3的mRNA表达在分泌中期显著上调。除分泌晚期外，TET蛋白在整个月经周期的子宫内膜上皮中普遍存在，而基质染色则呈散在分布。TET1的mRNA在基质细胞中对雌激素有显著上调反应。上皮细胞中所有三种TETs的转录在孕酮处理后被诱导。在用24小时雌激素和孕酮处理后，DNMT1显著下降，随后在24小时雌激素暴露后，上皮细胞中的DNMT3b和基质细胞中的DNMT1显著上调。本研究表明，TETs在子宫内膜中以细胞特异性、动态方式表达，并对类固醇激素有反应。单独研究TETs以及与DNMTs相关的作用，将有助于阐明子宫内膜生物学和病理学中的基因调控机制。
