ESPE Yearbook of Paediatric Endocrinology

Transl Psychiatry. 2022; 12(1): 132. PMID: 35354798https://pubmed.ncbi.nlm.nih.gov/35354798/

Brief Summary: This case control study identified widespread effects of fetal exposure to antenatal maternal glucocorticoid treatment on newborn bloodspot DNA methylation profiles.

Antenatal treatment with glucocorticoids (AGC), such as betamethasone or dexamethasone, is widely used in pregnancies at risk of preterm birth to promote fetal organ maturation and reduce perinatal morbidity. Epidemiological studies have identified associations between AGC exposure and increased risk for cardiometabolic, immune and neurodevelopmental disorders in the offspring (1-3). Altered DNA methylation (DNAm) that is sustained across cell divisions may represent a mechanism for mediating long-lasting phenotypic changes to environmental exposures. In a guinea pig model, the authors previously showed that betamethasone given antenatally altered the DNAm in the prefrontal cortex and hippocampus, and the differences in DNAm were associated with a more hyperactive phenotype. Four genes (C9orf116, Calb1, Glra3, and Gpr52) explained 20–29% of the observed variability in locomotor activity (4). In the current study, the authors analyzed DNAm 24-h post-birth in whole blood (obtained from dried blood spots) from 14 term-born infants exposed to betamethasone during late gestation (GW 24-33; 12 mgx2, 24 h apart) and compared them with controls.

Reduced Representation Bisulfite Sequencing (RRBS) libraries were prepared from 100 ng of high-quality dsDNA. RRBS libraries were sequenced using the Illumina NextSeq500 platform.

In total, 505 differentially methylated sites (DMCs) were identified in human neonatal blood following AGC treatment (≥5% methylation difference, FDR<0.05 for n=14/treatment), of which 231 sites were hypermethylated, representing 46%, and 274 were hypomethylated (54%). 15 sites, all hypomethylated (−25.91 to −43.25%), were localized within one DNase-H3K4me3 region (EH38E1382446). Examined in context of all 505 DMCs, region EH38E1382446 was observed in proximity to two additional DNase-H3K4me3 regions (EH38E1382445, EH38E1382449) and one promoter (E1382450), which were all hypomethylated (−7.89 to −43.25%, avg −22.55%). 35 DMCs were identified in this region, spanning 1432 base- pairs (chr1: 147078133-147079565).

The authors annotated 74 genes to hypermethylated DMCs, 100 genes to hypomethylated sites, and 45 genes to regions where methylation changes occurred in both directions. Of the top ten differentially methylated genes (HSPG2, USP48, CELA3B, SH3PXD2A, NTM, YEATS2, MCF2L2, CAMK2N2, MAP6D1, PKP3), four genes (HSPG2, USP48, CELA3B, NTM) contained glucocorticoid response elements (GRE) within their promoter regions, and five genes (USP48, SH3PXD2A, NTM, CAMK2N2, MAP6D1) are known to be highly expressed in the brain and have neurological roles.

In summary, antenatal GC treatment results in changes in DNA methylation in newborn blood. The differentially methylated genes were enriched for transcription regulation. Hypomethylated genes were enriched for pathways of proteasome activity. A number of the genes identified to be differentially methylated in human blood were also previously identified as differentially methylated in blood and hippocampus in guinea pigs following AGC treatment and were enriched for pathways of neurodevelopment. These findings enhance our understanding of the biological events that occur in response to exposure to prenatal glucocorticoids, such as ACS or maternal stress during pregnancy. The peripheral biomarkers presented in this study may help to identify individuals who are most at risk of developing altered phenotypes and enable future studies to design targeted intervention strategies and therapies to prevent or ameliorate the effects following prenatal adversity.

References: 1. Dean F, Yu C, Lingas RI, Matthews SG. Prenatal glucocorticoid modifies hypothalamo-pituitary-adrenal regulation in prepubertal guinea pigs. Neuroendocrinology. 2001; 73:194–202. 2. Sparrow S, Manning JR, Cartier J, Anblagan D, Bastin ME, Piyasena C, et al. Epi- genomic profiling of preterm infants reveals DNA methylation differences at sites associated with neural function. Transl Psychiatry. 2016; 6, page e716. 3. Moisiadis VG, Constantinof A, Kostaki A, Szyf M, Matthews SG. Prenatal Glucocorticoid exposure modifies endocrine function and behaviour for 3 generations following maternal and paternal transmission. Sci Rep. 2017;7: 118–14. 4. Sasaki A, Eng ME, Lee AH, Kostaki A, Matthews SG, DNA methylome signatures of prenatal exposure to synthetic glucocorticoids in hippocampus and peripheral whole blood of female guinea pigs in early life. Transl Psychiatry. 2021; 11: 63.