Department of Obstetrics and Gynecology, East Hospital, School of Medicine, Tongji University, Shanghai 200120, China.
Int J Clin Pract. 2023 Mar 18;2023:2291156. doi: 10.1155/2023/2291156. eCollection 2023.
Endometriosis, which is a common disease affecting approximately 10% of women of reproductive age, usually causes dysmenorrhea and infertility, thus seriously harming the patients' physical and mental health. However, there is a mean delay of 6.7 years between the onset of the symptoms and the surgical diagnosis of endometriosis. There is an increasing amount of evidence that suggests that epigenetic aberrations, including deoxyribonucleic acid (DNA) methylation, play a definite role in the pathogenesis of endometriosis. This study aimed to explore the noninvasive or minimally invasive biomarkers of this disease.
Six patients with surgically confirmed ovarian endometriosis and six patients who received IUD implantation for contraception without endometriosis were recruited in the East Hospital of Tongji University in 2018. The genome methylation profiling of the eutopic and ectopic endometrium of ovarian endometriosis patients and normal endometrial specimens from healthy women was determined using a methylation microarray test. The test screened methylation-differentiated 5'-C-phosphate-G-3' (CpG) sites and then located the target genes affected by these sites following sequence alignment. Then, an additional 22 patients and 26 healthy controls were enrolled to further verify the difference in the selected genes between endometriosis patients and healthy women. The differential DNA methylation of the selected genes was validated via direct bisulfite sequencing and analysis of their messenger ribonucleic acid (mRNA) levels using quantitative reverse transcription polymerase chain reaction (qRT-PCR).
Fifteen differentially methylated CpG sites were found among the patients and healthy women, and five CpG sites were mapped to the introns of the human leukocyte antigen-C (HLA-C) gene; these were highly polymorphic between different HLA-C alleles and were HLA-C07 specific. The results indicated that the HLA-C07 carrier patients exhibited significantly higher DNA methylation levels at the intron VII of HLA-C compared to the HLA-C07 carrier healthy controls. High HLA-C07 mRNA levels were also observed using qRT-PCR with HLA-C07-specific primers, which indicated that the hypermethylation of CpG in intron VII might suppress a silencer that regulates HLA-C07 expressions.
Deoxyribonucleic acid hypermethylation in the intron VII of the HLA-C07 gene appears to regulate the expression of HLA-C07. The aberrant DNA methylation in this region was positively correlated with the occurrence of endometriosis.
子宫内膜异位症是一种常见疾病，影响约 10%的育龄妇女，通常导致痛经和不孕，严重危害患者身心健康。然而，从症状出现到子宫内膜异位症的手术诊断之间存在平均 6.7 年的延迟。越来越多的证据表明，表观遗传异常，包括脱氧核糖核酸（DNA）甲基化，在子宫内膜异位症的发病机制中起重要作用。本研究旨在探讨这种疾病的非侵入性或微创性生物标志物。
2018 年，同济大学东方医院招募了 6 名经手术证实患有卵巢子宫内膜异位症的患者和 6 名因避孕而接受宫内节育器植入术且无子宫内膜异位症的患者。使用甲基化微阵列试验确定卵巢子宫内膜异位症患者的在位和异位子宫内膜以及健康女性正常子宫内膜标本的全基因组甲基化谱。该试验筛选出甲基化差异的 5'-C-磷酸-G-3'（CpG）位点，然后在序列比对后定位受这些位点影响的靶基因。然后，招募了另外 22 名患者和 26 名健康对照者，以进一步验证子宫内膜异位症患者和健康女性之间所选基因的差异。通过直接亚硫酸氢盐测序和定量逆转录聚合酶链反应（qRT-PCR）分析信使核糖核酸（mRNA）水平验证所选基因的差异 DNA 甲基化。
在患者和健康女性之间发现了 15 个差异甲基化的 CpG 位点，其中 5 个 CpG 位点映射到人白细胞抗原-C（HLA-C）基因的内含子；这些在不同 HLA-C 等位基因之间高度多态性，且 HLA-C07 特异性。结果表明，与 HLA-C07 携带者健康对照组相比，HLA-C07 携带者患者 HLA-C 内含子 VII 的 DNA 甲基化水平显著升高。使用 HLA-C07 特异性引物的 qRT-PCR 也观察到 HLA-C07 mRNA 水平升高，这表明内含子 VII 中 CpG 的高甲基化可能抑制了调节 HLA-C07 表达的沉默子。
HLA-C07 基因内含子 VII 的脱氧核糖核酸过度甲基化似乎调节 HLA-C07 的表达。该区域异常的 DNA 甲基化与子宫内膜异位症的发生呈正相关。
