Epigenetic signatures of maternal-fetal health: insights from cord blood and placenta

The placenta is vital for fetal growth, and its methylation patterns reflect placental function, affecting the fetus and providing insights into disease origins. While cord blood methylation is convenient for assessing the fetal environment, methylation profiles vary by tissue due to variance in cell populations, function, and life stage. As tissue differences extensively contribute to the DNA methylation patterns, using surrogate samples such as cord blood may result in inconsistent findings. In this study, we aim to quantify the correlation of cytosine-phosphate-guanine dinucleotides (CpGs) between paired cord blood and placenta samples. Using the Infinium Human Methylation 450 K BeadChip, we compared methylation patterns in cord blood mononuclear cells (CBMC; n = 54), the maternally-facing side of placental tissue (MP; n = 68), and the fetal-facing side of placental tissue (FP; n = 67). Methylation patterns from the FP (6,021 CpGs) were significantly correlated with CBMC compared to the MP (2,862 CpGs). These CpGs were related to the biological (mitotic cell) process and molecular function (ribonucleoprotein complex binding). Our findings quantified CpG site correlation between cord blood and placenta, providing a valuable reference for future studies on placental health that rely on cord blood methylation in the absence of placental biospecimens.

胎盘（placenta）对胎儿生长至关重要，其甲基化模式（methylation patterns）可反映胎盘功能，既影响胎儿发育，也能为疾病起源研究提供关键见解。尽管脐血（cord blood）甲基化检测在评估胎儿宫内环境时较为便捷，但由于细胞群体、功能及生命阶段的差异，不同组织的甲基化谱（methylation profiles）存在显著差异。鉴于组织差异对DNA甲基化模式（DNA methylation patterns）的影响广泛，使用脐血这类替代样本（surrogate samples）可能会导致研究结果不一致。本研究旨在量化配对脐血与胎盘样本间胞嘧啶-磷酸-鸟嘌呤二核苷酸（cytosine-phosphate-guanine dinucleotides，CpGs）的相关性。本研究采用Infinium 人类甲基化450K芯片（Infinium Human Methylation 450 K BeadChip），对脐血单个核细胞（cord blood mononuclear cells, CBMC；n=54）、胎盘母体侧组织（maternally-facing side of placental tissue, MP；n=68）及胎盘胎儿侧组织（fetal-facing side of placental tissue, FP；n=67）的甲基化模式进行了比较。结果显示，相较于胎盘母体侧（仅关联2862个CpGs），胎盘胎儿侧的甲基化模式与脐血单个核细胞呈现显著相关性，共涉及6021个CpGs。这些CpGs与有丝分裂细胞相关的生物学过程及核糖核蛋白复合物结合的分子功能密切相关。本研究量化了脐血与胎盘间的CpG位点相关性，可为未来在缺乏胎盘生物样本（placental biospecimens）时，依赖脐血甲基化检测开展胎盘健康相关研究提供重要参考价值。