An epigenome-wide association meta-analysis of prenatal maternal stress in neonates: A model approach for replication

Prenatal maternal stress exposure has been associated with neonatal differential DNA methylation. However, the available evidence in humans is largely based on candidate gene methylation studies, where only a few CpG sites were evaluated. The aim of this study was to examine the association between prenatal exposure to maternal stress and offspring genome-wide cord blood methylation using different methods. First, we conducted a meta-analysis and follow-up pathway analyses. Second, we used novel region discovery methods [i.e., differentially methylated regions (DMRs) analyses]. To this end, we used data from two independent population-based studies, the Generation R Study (n = 912) and the Avon Longitudinal Study of Parents and Children (ALSPAC, n = 828), to (i) measure genome-wide DNA methylation in cord blood and (ii) extract a prenatal maternal stress composite. The meta-analysis (n_total = 1,740) revealed no epigenome-wide (meta <i>P</i> &lt;1.00e-07) associations of prenatal maternal stress exposure with neonatal differential DNA methylation. Follow-up analyses of the top hits derived from our epigenome-wide meta-analysis (meta <i>P</i> &lt;1.00e-04) indicated an over-representation of the methyltransferase activity pathway. We identified no Bonferroni-corrected (<i>P</i> &lt;1.00e-06) DMRs associated with prenatal maternal stress exposure. Combining data from two independent population-based samples in an epigenome-wide meta-analysis, the current study indicates that there are no large effects of prenatal maternal stress exposure on neonatal DNA methylation. Such replication efforts are essential in the search for robust associations, whether derived from candidate gene methylation or epigenome-wide studies.

产前母体应激暴露已被证实与新生儿差异性DNA甲基化存在关联。然而，当前人类相关研究证据大多基于候选基因甲基化研究，此类研究仅评估了少量CpG位点。本研究旨在通过多种方法，探究产前母体应激暴露与子代全基因组脐带血甲基化水平之间的关联。首先，我们开展了元分析及后续通路分析；其次，采用了新颖的区域挖掘方法[即差异甲基化区域（DMRs）分析]。为此，我们使用了两项独立的基于人群的研究数据：Generation R研究（n=912）与雅芳父母与儿童纵向研究（ALSPAC，n=828），以(i)检测脐带血中的全基因组DNA甲基化水平，(ii)提取产前母体应激复合指标。总样本量为1740的元分析结果显示，产前母体应激暴露与新生儿差异性DNA甲基化之间不存在表观基因组范围内的显著关联（元分析P值<1.00×10^-7）。对本研究表观基因组范围元分析中排名靠前的候选位点（元分析P值<1.00×10^-4）开展后续分析后发现，甲基转移酶活性通路存在过度富集现象。本研究未发现经邦费罗尼校正（P值<1.00×10^-6）后仍具有统计学意义的、与产前母体应激暴露相关的DMRs。本研究通过整合两项独立人群样本的数据开展表观基因组范围元分析，结果表明产前母体应激暴露对新生儿DNA甲基化并无显著大效应。无论是基于候选基因甲基化研究还是表观基因组范围研究，此类重复性验证工作在探寻可靠关联的过程中均至关重要。