DNA methylation as a mediator of the association between prenatal adversity and risk factors for metabolic disease in adulthood
Tobi EW., Slieker RC., Luijk R., Dekkers KF., Stein AD., Xu KM., Slagboom PE., Van Zwet EW., Lumey LH., Heijmans BT., T'Hoen PA., Pool R., Van Greevenbroek MM., Stehouwer CD., Van Der Kallen CJ., Schalkwijk CG., Wijmenga C., Zhernakova S., Tigchelaar EF., Beekman M., Deelen J., Van Heemst D., Veldink JH., Van Den Berg LH., Van Duijn CM., Hofman A., Uitterlinden AG., Jhamai PM., Verbiest M., Verkerk M., Van Der Breggen R., Van Rooij J., Lakenberg N., Mei H., Bot J., Zhernakova DV., Van 't Hof P., Deelen P., Nooren I., Moed M., Vermaat M., Jan Bonder M., Van Dijk F., Van Galen M., Arindrarto W., Kielbasa SM., Swertz MA., Isaacs A., Franke L.
Copyright © 2018 The Authors, some rights reserved. Although it is assumed that epigenetic mechanisms, such as changes in DNA methylation (DNAm), underlie the relationship between adverse intrauterine conditions and adult metabolic health, evidence from human studies remains scarce. Therefore, we evaluated whether DNAm in whole blood mediated the association between prenatal famine exposure and metabolic health in 422 individuals exposed to famine in utero and 463 (sibling) controls. We implemented a two-step analysis, namely, a genome-wide exploration across 342, 596 cytosine-phosphate-guanine dinucleotides (CpGs) for potential mediators of the association between prenatal famine exposure and adult body mass index (BMI), serum triglycerides (TG), or glucose concentrations, which was followed by formalmediation analysis.DNAm mediated the association of prenatal famine exposure with adult BMI and TG but not with glucose. DNAm at PIM3 (cg09349128), a gene involved in energy metabolism, mediated 13.4% [95% confidence interval (CI), 5 to 28%] of the association between famine exposure and BMI. DNAm at six CpGs, including TXNIP (cg19693031), influencing b cell function, and ABCG1 (cg07397296), affecting lipid metabolism, together mediated 80% (95% CI, 38.5 to 100%) of the association between famine exposure and TG. Analyses restricted to those exposed to famine during early gestation identified additional CpGs mediating the relationship with TG near PFKFB3 (glycolysis) and METTL8 (adipogenesis). DNAm at the CpGs involved was associated with gene expression in an external data set and correlated with DNAm levels in fat depots in additional postmortem data. Our data are consistent with the hypothesis that epigenetic mechanisms mediate the influence of transient adverse environmental factors in early life on long-termmetabolic health. The specific mechanism awaits elucidation.