Novo Nordisk Foundation Center for Basic Metabolic Research, Metabolic Epigenetics Group, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Center for Pregnant Women With Diabetes, Department of Obstetrics, Rigshospitalet, Copenhagen, Denmark.
Clin Epigenetics. 2024 May 7;16(1):61. doi: 10.1186/s13148-024-01673-3.
Diabetes in pregnancy is associated with increased risk of long-term metabolic disease in the offspring, potentially mediated by in utero epigenetic variation. Previously, we identified multiple differentially methylated single CpG sites in offspring of women with gestational diabetes mellitus (GDM), but whether stretches of differentially methylated regions (DMRs) can also be identified in adolescent GDM offspring is unknown. Here, we investigate which DNA regions in adolescent offspring are differentially methylated in blood by exposure to diabetes in pregnancy. The secondary aim was to characterize the RNA expression of the identified DMR, which contained the nc886 non-coding RNA.
To identify DMRs, we employed the bump hunter method in samples from young (9-16 yr, n = 92) offspring of women with GDM (O-GDM) and control offspring (n = 94). Validation by pyrosequencing was performed in an adult offspring cohort (age 28-33 years) consisting of O-GDM (n = 82), offspring exposed to maternal type 1 diabetes (O-T1D, n = 67) and control offspring (O-BP, n = 57). RNA-expression was measured using RT-qPCR in subcutaneous adipose tissue and skeletal muscle.
One significant DMR represented by 10 CpGs with a bimodal methylation pattern was identified, located in the nc886/VTRNA2-1 non-coding RNA gene. Low methylation status across all CpGs of the nc886 in the young offspring was associated with maternal GDM. While low methylation degree in adult offspring in blood, adipose tissue, and skeletal muscle was not associated with maternal GDM, adipose tissue nc886 expression was increased in O-GDM compared to O-BP, but not in O-T1D. In addition, adipose tissue nc886 expression levels were positively associated with maternal pre-pregnancy BMI (p = 0.006), but not with the offspring's own adiposity.
Our results highlight that nc886 is a metastable epiallele, whose methylation in young offspring is negatively correlated with maternal obesity and GDM status. The physiological effect of nc886 may be more important in adipose tissue than in skeletal muscle. Further research should aim to investigate how nc886 regulation in adipose tissue by exposure to GDM may contribute to development of metabolic disease.
妊娠糖尿病与后代长期代谢疾病的风险增加有关，这种风险可能是由宫内表观遗传变异介导的。先前，我们在患有妊娠期糖尿病（GDM）的女性的后代中发现了多个差异甲基化的单 CpG 位点，但在青少年 GDM 后代中是否也能识别到差异甲基化区域（DMR）尚不清楚。在这里，我们研究了在妊娠糖尿病暴露下，青少年后代血液中哪些 DNA 区域存在差异甲基化。次要目的是描述所识别的 DMR 的 RNA 表达情况，其中包含 nc886 非编码 RNA。
为了识别 DMR，我们在 GDM 女性的年轻（9-16 岁，n=92）后代和对照后代（n=94）的样本中使用了凸起探测器方法。在由 GDM 后代（O-GDM，n=82）、暴露于母体 1 型糖尿病的后代（O-T1D，n=67）和对照后代（O-BP，n=57）组成的成年后代队列中，通过焦磷酸测序进行了验证。使用 RT-qPCR 在皮下脂肪组织和骨骼肌中测量 RNA 表达。
确定了一个由 10 个 CpG 组成的具有双峰甲基化模式的显著 DMR，位于 nc886/VTRNA2-1 非编码 RNA 基因中。年轻后代中所有 CpG 的 nc886 低甲基化状态与母亲的 GDM 有关。尽管血液、脂肪组织和骨骼肌中成年后代的低甲基化程度与母亲的 GDM 无关，但与 O-BP 相比，O-GDM 中的脂肪组织 nc886 表达增加，但 O-T1D 中没有。此外，脂肪组织 nc886 的表达水平与母亲的孕前 BMI 呈正相关（p=0.006），但与后代自身肥胖无关。
我们的研究结果表明，nc886 是一个不稳定的表观等位基因，其在年轻后代中的甲基化状态与母亲肥胖和 GDM 状态呈负相关。nc886 在脂肪组织中的生理作用可能比在骨骼肌中更为重要。进一步的研究应旨在研究 GDM 暴露后 nc886 在脂肪组织中的调节如何导致代谢疾病的发展。
