Early Onset Pre-Eclampsia Is Associated with Altered DNA Methylation of Cortisol-Signalling and Steroidogenic Genes in the Placenta

<div><p>Placental cortisol is inactivated in normotensive pregnancies, but is frequently present in pre-eclampsia associated placentae. Since glucocorticoids are strongly associated with the programming of long-term health, we assessed DNA methylation of genes involved in cortisol signalling and bioavailability, and hormonal signalling in the placenta of normotensive and hypertensive pregnancies. Candidate genes/CpG sites were selected through analysis of Illumina Infinium HumanMethylation450 BeadChip array data on control (n = 19) and early onset pre-eclampsia (EOPET; n = 19) placental samples. DNA methylation was further quantified by bisulfite pyrosequencing in a larger cohort of control (n = 111) cases, in addition to EOPET (n = 19), late onset pre-eclampsia (LOPET; n = 18) and normotensive intrauterine growth restriction (nIUGR; n = 13) cases. DNA methylation (percentage points) was increased at CpG sites within genes encoding the glucocorticoid receptor (<i>NR3C1</i> exon 1D promoter; +8.46%; <i>P</i><0.01) and corticotropin releasing hormone (CRH) binding protein (<i>CRHBP</i> intron 3; +9.14%; <i>P</i><0.05), and decreased within <i>CRH</i> (5′ UTR; −4.30%; <i>P</i> = 0.11) in EOPET-associated placentae, but not in LOPET nor nIUGR cases, compared to controls. Differential DNA methylation was not observed among groups at the 11β-hydroxysteroid dehydrogenase type 2 (<i>HSD11B2</i>) gene promoter. Significant hypomethylation was observed in pre-eclampsia but not nIUGR placentae for steroidogenic genes, including <i>CYP11A1</i> (exon1; EOPET; −9.66%; <i>P</i><0.00001, and LOPET; −5.77%; <i>P</i><0.001), 3β-hydroxy-delta-5-steroid dehydrogenase type 1 (<i>HSD3B1</i> exon 2; EOPET; −12.49%; <i>P</i><0.00001, and LOPET; −6.88%; <i>P</i><0.001), TEA domain family member 3 (<i>TEAD3</i> intron 1; EOPET; −12.56%; <i>P</i><0.00001) and <i>CYP19</i> (placental-specific exon 1.1 promoter; EOPET; −10.62%, <i>P</i><0.0001). These data represent dysregulation of the placental epigenome in pre-eclampsia related to genes involved in maintaining the hormonal environment during pregnancy and highlights particular susceptibility in the early onset syndrome.</p>