Placental Methylation Research Articles

Placental methylation and pro-inflammatory protein levels in cord blood

IntroductionThe neonates’ inflammatory response may in part be shaped during development by the placental epigenome, but evidence is scarce. We investigated the association between placental DNA methylation and pro-inflammatory proteins in cord blood. MethodsA total of 249 mother-child dyads from the Harvard Epigenetic Birth Cohort were included in this study. Genome-wide methylation in placental DNA was assessed using the Illumina Human Methylation 450 Bead Chip array and verified by pyrosequencing. Cord blood inflammation markers assessed were interleukin-6, interleukin-8 and tumor necrosis factor α, intercellular adhesion molecule 1, serum amyloid A, and C-reactive protein. ResultsWe identified differential placental DNA methylation of three loci in the HIVEP3 gene shore region that were associated with TNFα protein levels in cord blood. TNFα levels were associated with mode of delivery, gestational age and birth order. Three other loci located in the open sea region of the BCL11B gene were associated with SAA protein levels in cord blood. SAA levels were associated with birthweight, gestational age, and infant sex. ConclusionsOur results suggest a potential role for HIVEP3 and BCL11B placental DNA methylation in the acute immune response of the neonate. These immune markers were correlated with several mother and child characteristics.

Analyzing the Relationship Between Preeclamptic Severity and Placental Methylation

Analyzing the Relationship Between Preeclamptic Severity and Placental Methylation

Increased risk of severe neonatal opioid withdrawal syndrome in pregnancies with low placental ABCB1 DNA methylation.

Neonatal opioid withdrawal syndrome (NOWS) is unpredictable. We assessed relationships between placental DNA methylation with in-utero opioid exposure and NOWS severity. Secondary analysis of a prospective multicenter cohort study of pregnancies on methadone or buprenorphine, ≥34 weeks, singleton, 18 or greater. Placental biopsies were collected. Placental DNA methylation levels of ABCG1, ABCG2, CYP19A1, and HSD11B2 were quantified via pyrosequencing following bisulfite conversion. CYP19A1 mRNA levels and umbilical cord drug levels were determined by RT-qPCR and LC-MS respectively. Severe NOWS was diagnosed through Finnegan scoring. P value < 0.05 was significant. Thirty-eight dyads were included. Promoter region methylation for placental ABCB1 was lower in severe NOWS compared to non-severe NOWS (p = 0.04). Placental CYP19A1 methylation was inversely related to CYP19A1 mRNA levels and associated with umbilical cord norbuprenorphine levels (p < 0.01), but not umbilical cord methadone levels. Lower placental ABCB1 methylation was associated with severe NOWS. Higher placental CYP19A1 methylation correlated with higher umbilical cord norbuprenorphine levels.

The Role of Placental DNA Methylation at Reproduction-Related Genes in Associations between Prenatal Bisphenol Analogues Exposure and the Digit Ratio in Children at Age 4: A Birth Cohort Study.

Placental DNA methylation (DNAm) may be a potential mechanism underlying the effects of prenatal bisphenol analogues (BPs) exposure on reproductive health. Based on the Shanghai-Minhang Birth Cohort Study (S-MBCS), this study investigated associations of placental DNAm at reproduction-related genes with prenatal BPs exposure and children's digit ratios at age 4 using multiple linear regression models, and mediation analysis was further used to examine the mediating role of placental DNAm in the associations between prenatal BPs exposure and digit ratios among 345 mother-child pairs. Prenatal exposure to bisphenol A (BPA) was associated with hypermethylation at Protocadherin 8 (PCDH8), RBMX Like 2 (RBMXL2), and Sperm Acrosome Associated 1 (SPACA1), while bisphenol F (BPF) exposure was associated with higher methylation levels of Fibroblast Growth Factor 13 (FGF13). Consistent patterns were found in associations between higher DNAm at the 4 genes and increased digit ratios. Further mediation analysis showed that about 15% of the effect of BPF exposure on increased digit ratios was mediated by placental FGF13 methylation. In conclusion, the altered placental DNAm status might be a mediator underlying the feminizing effect of prenatal BPs exposure.

Differential impact of prenatal PTSD symptoms and preconception trauma exposure on placental NR3C1 and FKBP5 methylation

Perinatal stress is associated with altered placental methylation, which plays a critical role in fetal development and infant outcomes. This proof-of-concept pilot study investigated the impact of lifetime trauma exposure and perinatal PTSD symptoms on epigenetic regulation of placenta glucocorticoid signaling genes (NR3C1 and FKBP5). Lifetime trauma exposure and PTSD symptoms during pregnancy were assessed in a racially/ethnically diverse sample of pregnant women (N = 198). Participants were categorized into three groups: (1) No Trauma (−T); (2) Trauma, No Symptoms (T − S); and (3) Trauma and Symptoms (T + S). Placental tissue was analyzed via bisulfite pyrosequencing for degree of methylation at the NR3C1 promoter and FKBP5 regulatory regions. Analyses of covariance were used to test group differences in percentages of NR3C1 and FKBP5 methylation overall and at each CpG site. We found a significant impact of PTSD symptoms on placental NR3C1 methylation. Compared to the −T group, the T + S group had greater NR3C1 methylation overall and at CpG6, CpG8, CpG9, and CpG13, but lower methylation at CpG5. The T + S group had significantly higher NR3C1 methylation overall and at CpG8 compared to the T − S group. There were no differences between the T − S group and − T group. Additionally, no group differences emerged for FKBP5 methylation. Pregnant trauma survivors with PTSD symptoms exhibited differential patterns of placental NR3C1 methylation compared to trauma survivors without PTSD symptoms and pregnant women unexposed to trauma. Results highlight the critical importance of interventions to address the mental health of pregnant trauma survivors.

Sex-dependent placental methylation quantitative trait loci provide insight into the prenatal origins of childhood onset traits and conditions

Molecular quantitative trait loci (QTLs) allow us to understand the biology captured in genome-wide association studies (GWASs). The placenta regulates fetal development and shows sex differences in DNA methylation. We therefore hypothesized that placental methylation QTL (mQTL) explain variation in genetic risk for childhood onset traits, and that effects differ by sex. We analyzed 411 term placentas from two studies and found 49,252 methylation (CpG) sites with mQTL and 2,489 CpG sites with sex-dependent mQTL. All mQTL were enriched in regions that typically affect gene expression in prenatal tissues. All mQTL were also enriched in GWAS results for growth- and immune-related traits, but male- and female-specific mQTL were more enriched than cross-sex mQTL. mQTL colocalized with trait loci at 777 CpG sites, with 216 (28%) specific to males or females. Overall, mQTL specific to male and female placenta capture otherwise overlooked variation in childhood traits.

Placental DNA methylation analysis of selective fetal growth restriction in monochorionic twins reveals aberrant methylated CYP11A1 gene for fetal growth restriction.

Fetal growth restriction (FGR) is associated with increased susceptibility to perinatal morbidity and mortality. Evidence suggests that epigenetic changes play critical roles in the regulation of fetal growth. We sought to present a comprehensive analysis of the associations between placental DNA methylation and selective fetal growth restriction (sFGR), which is a severe complication of monochorionic twin pregnancies, characterized by one fetus experiencing restricted growth. Genome-wide methylation analysis was performed on 24 placental samples obtained from 12 monochorionic twins with sFGR (Cohort 1) using Illumina Infinium MethylationEPIC BeadChip. Integrative analysis of our EPIC data and two previous placental methylation studies of sFGR (a total of 30 placental samples from 15 sFGR twins) was used to identify convincing differential promoter methylation. Validation analysis was performed on the placentas from 15 sFGR twins (30 placental samples), 15 FGR singletons, and 14 control singletons (Cohort 2) using pyrosequencing, quantitative real-time polymerase chain reaction, western blot, and immunohistochemistry (IHC). A globe shift toward hypomethylation was identified in the placentas of growth-restricted fetuses compared with the placentas of normal fetuses in monochorionic twins, including 5625 hypomethylated CpGs and 452 hypermethylated CpGs, especially in the regions of CpG islands, gene-body and promoters. The analysis of pathways revealed dysregulation primarily in steroid hormone biosynthesis, metabolism, cell adhesion, signaling transduction, and immune response. Integrative analysis revealed a differentially methylated promoter region in the CYP11A1 gene, encoding a rate-limiting enzyme of steroidogenesis converting cholesterol to pregnenolone. The CYP11A1 gene was validated to have hypomethylation and higher mRNA expression in sFGR twins and FGR singletons. In conclusion, our findings suggested that the changes in placental DNA methylation pattern in sFGR may have functional implications for differentially methylated genes and regulatory regions. The study provides reliable evidence for identifying abnormally methylated CYP11A1 gene in the placenta of sFGR.

The role of m6A methylation in prenatal maternal psychological distress and birth outcome

BackgroundPrenatal maternal psychological distress (PMPD) is a known risk factor for adverse birth outcomes. N6-methyladenosine RNA (m6A) methylation is crucial in moderating RNA biology. This study aimed to evaluate the relationships between PMPD, birth outcomes, and placental m6A methylation. MethodsThis was a prospective cohort study. PMPD exposure was assessed by questionnaires about prenatal stress, depression, and anxiety. Placental m6A methylation was measured using a colorimetric assay. The relationships between PMPD, m6A methylation, gestational age (GA), and birth weight (BW) were analyzed using structural equation models (SEMs). Maternal weight gain during pregnancy and infant sex were included as covariables. ResultsThe study included 209 mother-infant dyads. In an adjusted SEM, PMPD was associated with BW (B = −26.034; 95 % CI: −47.123, −4.868) and GA (B = −0.603; 95 % CI: −1.102, −0.154). M6A methylation was associated with PMPD (B = 0.055; 95 % CI: 0.040,0.073) and BW (B = −305.799; 95 % CI: −520.164, −86.460) but not GA. The effect of PMPD on BW was partially mediated by m6A methylation (B = −16.817; 95 % CI: −31.348, −4.638) and GA (B = −12.280; 95 % CI: −23.612, −3.079). Maternal weight gain was associated with BW (B = 5.113; 95 % CI: 0.229,10.438). LimitationsThe study sample size was small, and the specific mechanism of m6A methylation on birth outcomes needs to be further explored. ConclusionsIn this study, PMPD exposure negatively affected BW and GA. Placental m6A methylation was associated with PMPD and BW and partially mediated the effect of PMPD on BW. Our findings highlight the importance of perinatal psychological evaluation and intervention.

Placenta DNA methylation levels of the promoter region of the leptin receptor gene are associated with infant cortisol

The intrauterine environment and early life stress regulation are widely recognized as an early foundation for lifelong physical and mental health. Methylation of CpG sites in the placenta represents an epigenetic modification that can potentially affect placental function, influence fetal development, and ultimately impact the health of offspring by programming the hypothalamic-pituitary-adrenal (HPA) axis stress response during prenatal development. Leptin, an adipokine produced by the placenta, is essential for energy homeostasis. It is also epigenetically regulated by promoter DNA methylation. Mounting evidence suggests that leptin also affects the stress response system. Though heterogeneity in the early stress response system may influence life-long mental and physical health, few studies explicitly examine the heterogeneity in the newborn stress response system. Less is known about leptin's association with the human hypothalamic-pituitary-adrenocortical (HPA) axis early in life. This study sought to serve as a proof of concept study investigating the relationship between newborn cortisol output trajectories and placental leptin DNA methylation in 117 healthy newborns from socioeconomically and racially- and ethnically-diverse families. We characterized heterogeneity in newborn cortisol output during the NICU Network Neurobehavioral Scales exam in the first week of life with latent growth mixture models. We then evaluated whether leptin promoter (LEP) methylation in placental samples was associated with newborn cortisol trajectories. Our findings suggest that increased placental LEP methylation, which corresponds to decreased leptin production, is associated with infant cortisol trajectories marked by increased cortisol output in the NNNS exam. These results provide important insights into the role of placental leptin DNA methylation in human newborn HPA axis development and subsequent developmental origins of health and disease processes.

Prenatal Environmental Stressors and DNA Methylation Levels in Placenta and Peripheral Tissues of Mothers and Neonates Evaluated by Applying Artificial Neural Networks.

Exposure to environmental stressors during pregnancy plays an important role in influencing subsequent susceptibility to certain chronic diseases through the modulation of epigenetic mechanisms, including DNA methylation. Our aim was to explore the connections between environmental exposures during gestation with DNA methylation of placental cells, maternal and neonatal buccal cells by applying artificial neural networks (ANNs). A total of 28 mother-infant pairs were enrolled. Data on gestational exposure to adverse environmental factors and on mother health status were collected through the administration of a questionnaire. DNA methylation analyses at both gene-specific and global level were analyzed in placentas, maternal and neonatal buccal cells. In the placenta, the concentrations of various metals and dioxins were also analyzed. Analysis of ANNs revealed that suboptimal birth weight is associated with placental H19 methylation, maternal stress during pregnancy with methylation levels of NR3C1 and BDNF in placentas and mother's buccal DNA, respectively, and exposure to air pollutants with maternal MGMT methylation. Associations were also observed between placental concentrations of lead, chromium, cadmium and mercury with methylation levels of OXTR in placentas, HSD11B2 in maternal buccal cells and placentas, MECP2 in neonatal buccal cells, and MTHFR in maternal buccal cells. Furthermore, dioxin concentrations were associated with placental RELN, neonatal HSD11B2 and maternal H19 gene methylation levels. Current results suggest that exposure of pregnant women to environmental stressors during pregnancy could induce aberrant methylation levels in genes linked to several pathways important for embryogenesis in both the placenta, potentially affecting foetal development, and in the peripheral tissues of mothers and infants, potentially providing peripheral biomarkers of environmental exposure.

A multi-omic approach identifies an autism spectrum disorder (ASD) regulatory complex of functional epimutations in placentas from children born preterm.

Children born preterm are at heightened risk of neurodevelopmental impairments, including Autism Spectrum Disorder (ASD). The placenta is a key regulator of neurodevelopmental processes, though the precise underlying molecular mechanisms remain unclear. Here, we employed a multi-omic approach to identify placental transcriptomic and epigenetic modifications related to ASD diagnosis at age 10, among children born preterm. Working with the extremely low gestational age (ELGAN) cohort, we hypothesized that a pro-inflammatory placental environment would be predictive of ASD diagnosis at age 10. Placental messenger RNA (mRNA) expression, CpG methylation, and microRNA (miRNA) expression were compared among 368 ELGANs (28 children diagnosed with ASD and 340 children without ASD). A total of 111 genes displayed expression levels in the placenta that were associated with ASD. Within these ASD-associated genes is an ASD regulatory complex comprising key genes that predicted ASD case status. Genes with expression that predicted ASD case status included Ewing Sarcoma Breakpoint Region 1 (EWSR1) (OR: 6.57 (95% CI: 2.34, 23.58)) and Bromodomain Adjacent To Zinc Finger Domain 2A (BAZ2A) (OR: 0.12 (95% CI: 0.03, 0.35)). Moreover, of the 111 ASD-associated genes, nine (8.1%) displayed associations with CpG methylation levels, while 14 (12.6%) displayed associations with miRNA expression levels. Among these, LRR Binding FLII Interacting Protein 1 (LRRFIP1) was identified as being under the control of both CpG methylation and miRNAs, displaying an OR of 0.42 (95% CI: 0.17, 0.95). This gene, as well as others identified as having functional epimutations, plays a critical role in immune system regulation and inflammatory response. In summary, a multi-omic approach was used to identify functional epimutations in the placenta that are associated with the development of ASD in children born preterm, highlighting future avenues for intervention.

Sex-based differences in placental DNA methylation profiles related to gestational age: an NIH ECHO meta-analysis

ABSTRACT The placenta undergoes many changes throughout gestation to support the evolving needs of the foetus. There is also a growing appreciation that male and female foetuses develop differently in utero, with unique epigenetic changes in placental tissue. Here, we report meta-analysed sex-specific associations between gestational age and placental DNA methylation from four cohorts in the National Institutes of Health (NIH) Environmental influences on Child Health Outcomes (ECHO) Programme (355 females/419 males, gestational ages 23–42 weeks). We identified 407 cytosine-guanine dinucleotides (CpGs) in females and 794 in males where placental methylation levels were associated with gestational age. After cell-type adjustment, 55 CpGs in females and 826 in males were significant. These were enriched for biological processes critical to the immune system in females and transmembrane transport in males. Our findings are distinct between the sexes: in females, associations with gestational age are largely explained by differences in placental cellular composition, whereas in males, gestational age is directly associated with numerous alterations in methylation levels.

Prenatal maternal anxiety promotes atopic dermatitis in offspring via placental DNA methylation changes.

Maternal anxiety during pregnancy has been previously reported to be associated with atopic dermatitis (AD) in offspring. The potential mechanism is not yet proven but epigenetic change may be suggested. We examined whether maternal anxiety during pregnancy may alter placental DNA methylation, then develop AD in the offspring. We evaluated maternal anxiety at 36 weeks of gestation by self-reported questionnaires, the State-Trait Anxiety Inventory-Trait subscale (STAI-T), in the Cohort for Childhood Origin of Asthma and Allergic Diseases (COCOA) study. AD was diagnosed at 6 months of age by pediatric allergists. We stratified the subjects into four groups according to the STAI score of mothers and diagnosis of AD in children. Placental genome-wide methylation microarray was analyzed using Infinium 450K BeadChip and selected genes were validated by pyrosequencing. From microarray, several differential methylation sites were identified in AD and healthy subjects and in total subjects, regarding to the STAI scores. Among differential methylation sites in microarray, six sites were selected for pyrosequencing. And site of matrix metalloproteinases 27 (MMP27) among 6 sites showed decreased methylation in AD infants with high STAI mothers compared to healthy infants with low STAI mothers. Epigenetic change in placenta can be a suggesting mechanism for the development of AD in offspring at 6 months of age associated with maternal anxiety during pregnancy and MMP27 may be a candidate gene.

Select Early-Life Environmental Exposures and DNA Methylation in the Placenta.

To summarize recent literature relating early-life environmental exposures on DNA methylation in the placenta, to identify how variation in placental methylation is regulated in an exposure-specific manner, and to encourage additional work in this area. Multiple studies have evaluated associations between prenatal environmental exposures and placental methylation in both gene-specific and epigenome-wide frameworks. Specific exposures lead to unique variability in methylation, and cross-exposure assessments have uncovered certain genes that demonstrate consistency in differential placental methylation. Exposure studies that assess methylation effects in a trimester-specific approach tend to find larger effects during the 1st trimester exposure. Earlier studies have more targeted gene-specific approaches to methylation, while later studies have shifted towards epigenome-wide, array-based approaches. Studies focusing on exposures such as air pollution, maternal smoking, environmental contaminants, and trace metals appear to be more abundant, while studies of socioeconomic adversity and circadian disruption are scarce but demonstrate remarkable effects. Understanding the impacts of early-life environmental exposures on placental methylation is critical to establishing the link between the maternal environment, epigenetic variation, and long-term health. Future studies into this field should incorporate repeated measures of exposure throughout pregnancy, in order to determine the critical windows in which placental methylation is most heavily affected. Additionally, the use of methylation-based scores and sequencing technology could provide important insights into epigenetic gestational age and uncovering more genomic regions where methylation is affected. Studies examining the impact of other exposures on methylation, including pesticides, alcohol, and other chemicals are also warranted.

Association between placental DNA methylation and fetal congenital heart disease.

Congenital heart disease (CHD) is a worldwide problem with high morbidity and mortality. Early diagnosis of congenital heart disease is still a challenge in clinical work. In recent years, few studies indicated that placental methylation may be predictors of CHD. More studies are needed to confirm the association between placental methylation and CHD. The aim of this study was to investigate the association between prenatal placental DNA methylation and CHD. Placental tissues were obtained from four fetuses during the second trimester with isolated, non-syndromic congenital heart disease, including three cases with double outlet right ventricle (DORV) and one case with tetralogy of Fallot (TOF), and four unaffected fetuses as controls. The Illumina Infinium Human Methylation 850K BeadChip assay was employed to identify differential methylation sites (DMSs) and differential methylation regions (DMRs). Differential methylation was evaluated by comparing the β-values for individual CpG loci in cases vs. controls. In addition, the function of genes was assessed through KEGG enrichment analysis, Gene Ontology (GO) analysis and KEGG pathway analysis. Compared with the control group, we identified 9625 differential methylation genes on 26,202 DMSs (p < 0.05), of which 6997 were hyper-methylation and 2628 were hypo-methylation. The top 30 terms of GO biological process and KEGG enrichment analysis of DMSs were connected with multiple important pathways of heart development and disease. Ten differentially methylated regions and the genes related to DMRs, such as TLL1, CRABP1, FDFT1, and PCK2, were identified. The deformity caused by the loss of function of these genes is remarkably consistent with the clinical phenotype of our cases. The DNA methylation level of placental tissue is closely associated with fetal congenital heart disease.

Infertility and treatments used have minimal effects on first-trimester placental DNA methylation and gene expression

To determine if DNA methylation alterations exist in first trimester human placenta between conceptions utilizing fertility treatments and those that do not, and if so, if they are the result of underlying infertility or fertility treatments. We also assessed if significant alterations led to changes in gene expression. We compared DNA methylation of first trimester placenta from singleton pregnancies that resulted in live births from unassisted, non-IVF fertility treatment (NIFT), and IVF conceptions using the Infinium MethylationEPIC BeadChip array. Significant CpG sites were compared to corresponding RNA-seq analysis in similar cohorts to determine if methylation alterations lead to differences in gene expression. 138 singleton pregnancies undergoing chorionic villus sampling resulting in a live birth were recruited for methylation analysis (56 unassisted, 38 NIFT, 44 IVF conceptions). RNA-seq data consisted of 141 subjects (74 unassisted, 33 NIFT, and 34 IVF) of which 116 overlap with the methylation cohort. IVF conceived pregnancy, or pregnancy conceived via non-IVF fertility treatment such as ovulation induction and/or intrauterine insemination. Significant methylation changes at CpG sites after adjustment for multiple comparisons. Secondary outcome is gene expression changes of significant CpG sites. Of the 741,145 probes analyzed in placenta, few were significant at Bonferroni<0.05: 185 CpG sites (0.025%) significant in pregnancies conceived with fertility treatment (NIFT+IVF) vs unassisted conceptions; 28 in NIFT vs unassisted; 195 in IVF vs unassisted; and only 13 (0.0018%) significant in IVF vs NIFT conceptions. Of all significant CpG sites combined, 10% (35 total) were located in genes with suggestive gene expression changes (RNA-seq P<0.05), but none were significant after adjustment for multiple comparisons (RNA-seq FDR<0.05). None of the 13 differentially methylated probes in IVF vs NIFT placenta were located in genes with suggestive IVF vs NIFT gene expression differences. Underlying infertility is the most significant contributor to the minimal differences in first trimester placental methylation, and not the specific fertility treatment utilized, such as IVF.

Maternal blood pressure associates with placental DNA methylation both directly and through alterations in cell-type composition

BackgroundMaternal blood pressure levels reflect cardiovascular adaptation to pregnancy and proper maternal-fetal exchanges through the placenta and are very sensitive to numerous environmental stressors. Maternal hypertension during pregnancy has been associated with impaired placental functions and with an increased risk for children to suffer from cardiovascular and respiratory diseases later on. Investigating changes in placental DNA methylation levels and cell-type composition in association with maternal blood pressure could help elucidate its relationships with placental and fetal development.MethodsTaking advantage of a large cohort of 666 participants, we investigated the association between epigenome-wide DNA methylation patterns in the placenta, measured using the Infinium HumanMethylation450 BeadChip, placental cell-type composition, estimated in silico, and repeated measurements of maternal steady and pulsatile blood pressure indicators during pregnancy.ResultsAt the site-specific level, no significant association was found between maternal blood pressure and DNA methylation levels after correction for multiple testing (false discovery rate < 0.05), but 5 out of 24 previously found CpG associations were replicated (p-value < 0.05). At the regional level, our analyses highlighted 64 differentially methylated regions significantly associated with at least one blood pressure component, including 35 regions associated with mean arterial pressure levels during late pregnancy. These regions were found enriched for genes implicated in lung development and diseases. Further mediation analyses show that a significant part of the association between steady blood pressure—but not pulsatile pressure—and placental methylation can be explained by alterations in placental cell-type composition. In particular, elevated blood pressure levels are associated with a decrease in the ratio between mesenchymal stromal cells and syncytiotrophoblasts, even in the absence of preeclampsia.ConclusionsThis study provides the first evidence that the association between maternal steady blood pressure during pregnancy and placental DNA methylation is both direct and partly explained by changes in cell-type composition. These results could hint at molecular mechanisms linking maternal hypertension to lung development and early origins of childhood respiratory problems and at the importance of controlling maternal blood pressure during pregnancy.

CpG methylation patterns in placenta and neonatal blood are differentially associated with neonatal inflammation.

Infants born extremely premature are at increased risk for health complications later in life for which neonatal inflammation may be a contributing biological driver. Placental CpG methylation provides mechanistic information regarding the relationship between prenatal epigenetic programming, prematurity, neonatal inflammation, and later-in-life health. We contrasted CpG methylation in the placenta and neonatal blood spots in relation to neonatal inflammation in the Extremely Low Gestational Age Newborn (ELGAN) cohort. Neonatal inflammation status was based on the expression of six inflammation-related proteins, assessed as (1) day-one inflammation (DOI) or (2) intermittent or sustained systemic inflammation (ISSI, inflammation on ≥2 days in the first 2 postnatal weeks). Epigenome-wide CpG methylation was assessed in 354 placental samples and 318 neonatal blood samples. Placental CpG methylation displayed the strongest association with ISSI (48 CpG sites) but was not associated with DOI. This was in contrast to CpG methylation in blood spots, which was associated with DOI (111 CpG sites) and not with ISSI (one CpG site). Placental CpG methylation was strongly associated with ISSI, a measure of inflammation previously linked to later-in-life cognitive impairment, while day-one neonatal blood methylation was associated with DOI. Neonatal inflammation increases the risk of adverse later-life outcomes, especially in infants born extremely preterm. CpG methylation in the placenta and neonatal blood spots were evaluated in relation to neonatal inflammation assessed via circulating proteins as either (i) day-one inflammation (DOI) or (ii) intermittent or sustained systemic inflammation (ISSI, inflammation on ≥2 days in the first 2 weeks). Tissue specificity was observed in epigenetic-inflammatory relationships: placental CpG methylation was associated with ISSI, neonatal blood CpG methylation was associated with DOI. Supporting the placental origins of disease framework, placental epigenetic patterns are associated with a propensity for ISSI in neonates.

Placental DNA Methylation Abnormalities in Prenatal Conotruncal Heart Defects.

Objective: This study aims to characterize the abnormal changes in placental DNA methylation associated with conotruncal heart defects (CTDs) and the level of methylation as epigenetic biomarkers for CTDs detection. Methods: This was a prospective study involving 28 fetuses diagnosed with CTDs in the second trimester at Beijing Anzhen Hospital between September 2020 and June 2021. These cases were classified into four groups based on their subtypes. 12 normal fetuses were used as controls. Placental tissue was obtained after inducing labor in fetuses. To identify differential methylation sites (DMSs) and regions (DMRs) in cases vs. controls, an Infinium Human Methylation 850 k bead chip was used. Differential methylation was assessed by comparing the β-values for individual CpG loci. Based on the p-value (<0.05), the most discriminating CpG sites were identified. The area under the receiver-operating-characteristics curve (AUC) was used to determine the predictive accuracy of CpG loci with significant methylation changes for CTDs. The function of genes was assessed through KEGG enrichment analysis, Gene Ontology (GO) analysis, and KEGG pathway analysis. Results: In comparison to the control group, the DNA methylation of the placental tissue is significantly different in fetuses with CTDs. We identified the most significantly different methylated loci and they demonstrated excellent individual predictive accuracy for CTDs detection with AUC >0.9 in cases compared with controls. HOXD9, CNN1, NOTCH1, and ECE1 were identified as CTDs-detection candidate genes. Conclusion Our study established the abnormal changes in placental methylation associated with CTDs and potential epigenetic biomarkers for CTDs detection.

Maternal Oxidized Soybean Oil Administration in Rats during Pregnancy and Lactation Alters the Intestinal DNA Methylation in Offspring.

As a food contaminant, oxidized oil or lipid oxidative products have been proven to exert toxicological effects on the growth and development of animals and humans. Research shows that maternal oxidative stress damage might transmit to another generation by epigenetic modulation. However, current evidence is still not clear on the mechanism of the effects of dietary oxidized oil during pregnancy on the two generations. This study employed a rat model fed with oxidized soybean oil (OSO) during pregnancy and lactation to explore the effects of the oxidative degree (0, 200, 400, and 800 mequiv of O2/kg) on the placental RNA methylation and DNA methylation in offspring jejunum. The results showed that following the ingestion of OSO, the placental genes of different m6A methylation were significantly enriched to nutrient metabolic processes and hormone activity. In addition, the intestine in offspring hypofunctioned observably, such as reducing the height of villi and the level of anti-inflammatory cytokine. Furthermore, maternal intake of OSO during pregnancy can damage the intestinal barrier function of offspring by inhibiting the proliferation and differentiation of intestinal epithelial cells and reducing the activity of intestinal DNA methyltransferase. In conclusion, this study reinforces the assertion that maternal OSO consumption during gestation and lactation negatively affects the placental health and intestinal development of suckling pups.