Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao, 266003, China.
Gynecology and Obstetrics Department, The Affiliated Hospital of Qingdao University, Qingdao, China.
Reprod Sci. 2020 Feb;27(2):468-476. doi: 10.1007/s43032-019-00038-z. Epub 2020 Feb 3.
Pre-eclampsia (PE) is a serious pregnancy complication defined as hypertension combined with proteinuria. Previous report has indicated that the expression of connective tissue growth factor (CTGF) is upregulated in PE placentas. In this study, we aim to investigate the potential association between the methylation of the CTGF promoter and PE. The methylation status of CTGF promoter was assessed by methylation-specific PCR and the expression of CTGF was analyzed by real-time quantitative PCR and immunohistochemistry staining, in placental samples from PE patients and normal pregnant women. The methylation level of the CTGF promoter was also analyzed in peripheral blood DNA samples from 90 PE patients and 94 normal pregnant women and further confirmed by methylation-sensitive restriction enzyme digestion combined with real-time PCR. We found a decreased methylation rate of CTGF promoter in PE placentas compared with normal control. In addition, the frequency of hemimethylated (UM) promoter of CTGF in peripheral blood was significantly lower in the PE group (P = 0.019), while the frequency of overall methylated (MU + MM) promoter of CTGF in peripheral blood was lower (borderline significance P = 0.043) in the PE group. The percentage of methylated CpG in CTGF promoter was 30% lower in maternal blood of PE subjects than in controls. Moreover, the lower methylation frequency of CTGF promoter was in accordance with the higher expression of CTGF in trophoblast cells. Together, our data suggested an association between PE and the hypomethylation of CTGF promoter both in placentas and peripheral blood from a Chinese Han population.
子痫前期 (PE) 是一种严重的妊娠并发症，定义为高血压合并蛋白尿。先前的报告表明，结缔组织生长因子 (CTGF) 的表达在 PE 胎盘组织中上调。在这项研究中，我们旨在研究 CTGF 启动子甲基化与 PE 之间的潜在关联。通过甲基化特异性 PCR 评估 CTGF 启动子的甲基化状态，通过实时定量 PCR 和免疫组织化学染色分析 CTGF 的表达，在 PE 患者和正常孕妇的胎盘样本中进行。还分析了 90 名 PE 患者和 94 名正常孕妇外周血 DNA 样本中 CTGF 启动子的甲基化水平，并通过甲基敏感限制性内切酶消化结合实时 PCR 进一步证实。我们发现 PE 胎盘组织中 CTGF 启动子的甲基化率降低。此外，PE 组外周血中 CTGF 启动子的半甲基化（UM）频率显著降低（P=0.019），而外周血中 CTGF 启动子的总甲基化（MU+MM）频率较低（边缘显著性 P=0.043）。PE 组母体血液中 CTGF 启动子的甲基化 CpG 百分比比对照组低 30%。此外，CTGF 启动子较低的甲基化频率与滋养细胞中 CTGF 的高表达一致。总之，我们的数据表明，在中国汉族人群中，PE 与 CTGF 启动子的低甲基化之间存在关联，无论是在胎盘还是外周血中。
