scholarly journals Maternal blood metal concentrations and whole blood DNA methylation during pregnancy in the Early Autism Risk Longitudinal Investigation (EARLI)

Author(s):  
Max T. Aung ◽  
Kelly M. Bakulski ◽  
Jason I. Feinberg ◽  
John F. Dou ◽  
John D. Meeker ◽  
...  

AbstractBackgroundMetals exposures have important health effects in pregnancy. The maternal epigenome may be responsive to these exposures. We tested whether metals are associated with concurrent differential maternal whole blood DNA methylation.MethodsIn the Early Autism Risk Longitudinal Investigation (EARLI) cohort, we measured first or second trimester maternal blood metals concentrations (cadmium, lead, mercury, manganese, and selenium) in 215 participants using inductively coupled plasma mass spectrometry. DNA methylation in maternal whole blood was measured in the same specimens on the Illumina 450K array (201 participants). A subset sample of 97 women had both measures available for analysis, all of whom did not report smoking during pregnancy. Linear regression was used to test for site-specific associations between individual metals and DNA methylation, adjusting for cell type composition and confounding variables. Discovery gene ontology analysis was conducted on the top 1,000 sites associated with each metal to elucidate downstream pathways.ResultsIn multiple linear regression, we observed hypermethylation at 11 DNA methylation sites associated with lead (FDR q-value <0.1), near the genes CYP24A1, ASCL2, FAT1, SNX31, NKX6-2, LRC4C, BMP7, HOXC11, PCDH7, ZSCAN18, and VIPR2. Lead associated sites were enriched (FDR q-value <0.1) for the pathways cell adhesion, nervous system development, and calcium ion binding. Manganese was associated with hypermethylation at four DNA methylation sites (FDR q-value <0.1), one of which was near the gene ARID2. Manganese associated sites were enriched for cellular metabolism pathways (FDR q-value<0.1). Effect estimates for DNA methylation sites associated (p<0.05) with cadmium, lead, and manganese were highly correlated (Pearson ρ >0.86).DiscussionSingle DNA methylation sites associated with lead and manganese may be potential biomarkers of exposure or implicate downstream gene pathways. Future studies should replicate our findings to characterize potential toxicological mechanisms of trace metals through the maternal epigenome.

Epigenetics ◽  
2021 ◽  
pp. 1-16
Author(s):  
Max T. Aung ◽  
Kelly M. Bakulski ◽  
Jason I. Feinberg ◽  
John F. Dou ◽  
John D. Meeker ◽  
...  

2021 ◽  
Vol 14 ◽  
Author(s):  
Kelly M. Bakulski ◽  
John F. Dou ◽  
Jason I. Feinberg ◽  
Max T. Aung ◽  
Christine Ladd-Acosta ◽  
...  

Background: Pregnancy measures of DNA methylation, an epigenetic mark, may be associated with autism spectrum disorder (ASD) development in children. Few ASD studies have considered prospective designs with DNA methylation measured in multiple tissues and tested overlap with ASD genetic risk loci.Objectives: To estimate associations between DNA methylation in maternal blood, cord blood, and placenta and later diagnosis of ASD, and to evaluate enrichment of ASD-associated DNA methylation for known ASD-associated genes.Methods: In the Early Autism Risk Longitudinal Investigation (EARLI), an ASD-enriched risk birth cohort, genome-scale maternal blood (early n = 140 and late n = 75 pregnancy), infant cord blood (n = 133), and placenta (maternal n = 106 and fetal n = 107 compartments) DNA methylation was assessed on the Illumina 450k HumanMethylation array and compared to ASD diagnosis at 36 months of age. Differences in site-specific and global methylation were tested with ASD, as well as enrichment of single site associations for ASD risk genes (n = 881) from the Simons Foundation Autism Research Initiative (SFARI) database.Results: No individual DNA methylation site was associated with ASD at genome-wide significance, however, individual DNA methylation sites nominally associated with ASD (P &lt; 0.05) in each tissue were highly enriched for SFARI genes (cord blood P = 7.9 × 10–29, maternal blood early pregnancy P = 6.1 × 10–27, maternal blood late pregnancy P = 2.8 × 10–16, maternal placenta P = 5.6 × 10–15, fetal placenta P = 1.3 × 10–20). DNA methylation sites nominally associated with ASD across all five tissues overlapped at 144 (29.5%) SFARI genes.Conclusion: DNA methylation sites nominally associated with later ASD diagnosis in multiple tissues were enriched for ASD risk genes. Our multi-tissue study demonstrates the utility of examining DNA methylation prior to ASD diagnosis.


2019 ◽  
Author(s):  
Kathleen Cheung ◽  
Marjolein J. Burgers ◽  
David A. Young ◽  
Simon Cockell ◽  
Louise N. Reynard

AbstractBackgroundDNA methylation of CpG sites is commonly measured using Illumina Infinium BeadChip platforms. The Infinium MethylationEPIC array has replaced the Infinium Methylation450K array. The two arrays use the same technology, with the EPIC array assaying 865859 CpG sites, almost double the number of sites present on the 450K array. In this study, we compare DNA methylation values of shared CpGs of the same human cartilage samples assayed using both platforms.MethodsDNA methylation was measured in 21 human cartilage samples using the Illumina Infinium Methylation450K BeadChip and the Infinium methylationEPIC array. Additional matched 450K and EPIC data in whole tumour and whole blood were downloaded from GEO GSE92580 and GSE86833 respectively. Data were processed using the Bioconductor package Minfi. Additionally, DNA methylation of six CpG sites was validated for the same 21 cartilage samples by use of pyrosequencing.ResultsIn cartilage samples, overall sample correlations between methylation values generated by the two arrays were high (Pearson correlation coefficient r > 0.96). However, 50.5% of CpG sites showed poor correlation (r < 0.2) between arrays. Sites with limited variance and with either very high or very low methylation levels in cartilage exhibited lower correlation values, corroborating prior studies in whole blood. Bisulfite pyrosequencing did not highlight one array as generating more accurate methylation values that the other. For a specific CpG site, the array methylation correlation coefficient differed between cartilage, tumour and whole blood, reflecting the difference in methylation variance between cell types. These patterns can be observed across different tissues with different CpG site variances. When performing differential methylation analysis, the mean probe correlation co-efficient increased with increasing Δβ threshold used.ConclusionCpG sites with low variability within a tissue showed poor reproducibility between arrays. However, variance and thus reproducibility differs across different tissue types. Therefore, researchers should be cautious when analysing methylation of CpG sites that show low methylation variance within the cell type of interest, regardless of platform or method used to assay methylation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aya Sasaki ◽  
Margaret E. Eng ◽  
Abigail H. Lee ◽  
Alisa Kostaki ◽  
Stephen G. Matthews

AbstractSynthetic glucocorticoids (sGC) are administered to women at risk of preterm delivery, approximately 10% of all pregnancies. In animal models, offspring exposed to elevated glucocorticoids, either by administration of sGC or endogenous glucocorticoids as a result of maternal stress, show increased risk of developing behavioral, endocrine, and metabolic dysregulation. DNA methylation may play a critical role in long-lasting programming of gene regulation underlying these phenotypes. However, peripheral tissues such as blood are often the only accessible source of DNA for epigenetic analyses in humans. Here, we examined the hypothesis that prenatal sGC administration alters DNA methylation signatures in guinea pig offspring hippocampus and whole blood. We compared these signatures across the two tissue types to assess epigenetic biomarkers of common molecular pathways affected by sGC exposure. Guinea pigs were treated with sGC or saline in late gestation. Genome-wide modifications of DNA methylation were analyzed at single nucleotide resolution using reduced representation bisulfite sequencing in juvenile female offspring. Results indicate that there are tissue-specific as well as common methylation signatures of prenatal sGC exposure. Over 90% of the common methylation signatures associated with sGC exposure showed the same directionality of change in methylation. Among differentially methylated genes, 134 were modified in both hippocampus and blood, of which 61 showed methylation changes at identical CpG sites. Gene pathway analyses indicated that prenatal sGC exposure alters the methylation status of gene clusters involved in brain development. These data indicate concordance across tissues of epigenetic programming in response to alterations in glucocorticoid signaling.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Chen Yao ◽  
Roby Joehanes ◽  
Rory Wilson ◽  
Toshiko Tanaka ◽  
Luigi Ferrucci ◽  
...  

Abstract Background DNA methylation is a key epigenetic modification that can directly affect gene regulation. DNA methylation is highly influenced by environmental factors such as cigarette smoking, which is causally related to chronic obstructive pulmonary disease (COPD) and lung cancer. To date, there have been few large-scale, combined analyses of DNA methylation and gene expression and their interrelations with lung diseases. Results We performed an epigenome-wide association study of whole blood gene expression in ~ 6000 individuals from four cohorts. We discovered and replicated numerous CpGs associated with the expression of cis genes within 500 kb of each CpG, with 148 to 1,741 cis CpG-transcript pairs identified across cohorts. We found that the closer a CpG resided to a transcription start site, the larger its effect size, and that 36% of cis CpG-transcript pairs share the same causal genetic variant. Mendelian randomization analyses revealed that hypomethylation and lower expression of CHRNA5, which encodes a smoking-related nicotinic receptor, are causally linked to increased risk of COPD and lung cancer. This putatively causal relationship was further validated in lung tissue data. Conclusions Our results provide a large and comprehensive association study of whole blood DNA methylation with gene expression. Expression platform differences rather than population differences are critical to the replication of cis CpG-transcript pairs. The low reproducibility of trans CpG-transcript pairs suggests that DNA methylation regulates nearby rather than remote gene expression. The putatively causal roles of methylation and expression of CHRNA5 in relation to COPD and lung cancer provide evidence for a mechanistic link between patterns of smoking-related epigenetic variation and lung diseases, and highlight potential therapeutic targets for lung diseases and smoking cessation.


2021 ◽  
Vol 23 (1) ◽  
Author(s):  
M. Badii ◽  
O. I. Gaal ◽  
M. C. Cleophas ◽  
V. Klück ◽  
R. Davar ◽  
...  

Abstract Objectives Hyperuricemia is a metabolic condition central to gout pathogenesis. Urate exposure primes human monocytes towards a higher capacity to produce and release IL-1β. In this study, we assessed the epigenetic processes associated to urate-mediated hyper-responsiveness. Methods Freshly isolated human peripheral blood mononuclear cells or enriched monocytes were pre-treated with solubilized urate and stimulated with LPS with or without monosodium urate (MSU) crystals. Cytokine production was determined by ELISA. Histone epigenetic marks were assessed by sequencing immunoprecipitated chromatin. Mice were injected intraarticularly with MSU crystals and palmitate after inhibition of uricase and urate administration in the presence or absence of methylthioadenosine. DNA methylation was assessed by methylation array in whole blood of 76 participants with normouricemia or hyperuricemia. Results High concentrations of urate enhanced the inflammatory response in vitro in human cells and in vivo in mice, and broad-spectrum methylation inhibitors reversed this effect. Assessment of histone 3 lysine 4 trimethylation (H3K4me3) and histone 3 lysine 27 acetylation (H3K27ac) revealed differences in urate-primed monocytes compared to controls. Differentially methylated regions (e.g. HLA-G, IFITM3, PRKAB2) were found in people with hyperuricemia compared to normouricemia in genes relevant for inflammatory cytokine signaling. Conclusion Urate alters the epigenetic landscape in selected human monocytes or whole blood of people with hyperuricemia compared to normouricemia. Both histone modifications and DNA methylation show differences depending on urate exposure. Subject to replication and validation, epigenetic changes in myeloid cells may be a therapeutic target in gout.


Circulation ◽  
2021 ◽  
Vol 143 (Suppl_1) ◽  
Author(s):  
Cuilin Zhang ◽  
Jing Wu ◽  
Marion Ouidir ◽  
Stefanie Hinkle ◽  
Fasil Ayele

Background: Accumulating evidence support the intergenerational impacts of diet in pregnancy. The underlying mechanisms, however, remain unclear. Placental epigenetic mechanisms may be involved although data from human epidemiological studies are sparse. We aimed to investigate associations of dietary quality in pregnancy with epigenome-wide placental DNA methylation in a multiracial pregnancy cohort. Methods: DNA methylation was measured using the Illumina Infinium Human Methylation450 Beadchip on placentas obtained at delivery from 301 pregnant women who participated in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Fetal Growth Studies-Singleton cohort. Dietary information during periconception and early first trimester was collected using food frequency questionnaires, and diet in the second and third trimester was collected using a 24-hour dietary recall during four study visits. Scores for adherence to three healthy dietary patterns, alternate Healthy Eating Index (aHEI), alternate Mediterranean Diet (aMED), and Dietary Approaches to Stop Hypertension (DASH), were calculated. For associations of each dietary pattern score with methylation, we conducted analyses using robust linear regression models after the adjustment for age, pre-pregnancy body mass index, race/ethnicity, physical activity, total energy intakes, and population stratification. Genes annotating the top significant CpG sites (false discovery rate (FDR) adjusted P<0.05) were queried for enrichment of functional pathways using the Ingenuity Pathway Analysis tool. Results: Adherence to aHEI was significantly associated with methylation of 8 CpG sites, with the most significant association manifested in cg16724319- MDH1B (P=1.9x10 -10 ). Adherence to aMED was related to methylation of 14 CpG sites, with the most significant association manifested in cg07835181- CLCN7 (P=1.7x10 -11 ). DASH was significantly related to 33 CpG sites, with the most significant association manifested in cg26292547- REV3L (P=4.4x10 -10 ). Further, genes annotating the significant CpG sites were enriched in pathways related to cardiovascular and nervous system development and function, cancer, organismal injury and abnormalities, and reproductive system diseases. Conclusion: Findings from the epigenome wide study suggest that overall dietary quality in pregnancy is associated with placental DNA methylation changes at different loci potentially related to cardiovascular, neurological, reproductive, and cancer phenotypes.


2015 ◽  
Vol 2 (2) ◽  
pp. 145-154 ◽  
Author(s):  
E. Andres Houseman ◽  
Stephanie Kim ◽  
Karl T. Kelsey ◽  
John K. Wiencke
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