Epigenetics

Intrauterine stress exposure is associated with offspring health. DNA methylation (DNAm) is as a putative underlying mechanism, but large population-based studies reported limited associations between prenatal stress and DNAm. Recent research has shown that environmental factors in interaction with genetic variants are better predictors of DNAm than environment or genotype alone. We investigated whether interactions of maternal prenatal stress with genetic variants are associated with DNAm at birth. We examined 2,963 mother-child pairs from the population-based Generation R Study and Avon Longitudinal Study of Parents and Children, using a harmonized, comprehensive cumulative prenatal stress measure. We tested genome-wide genotype-by-prenatal stress interactions on epigenome-wide DNAm (GxEmodel), and models including only genetic variants (Gmodel) or prenatal stress (Emodel) as predictors. Follow-up analyses included Gene Ontology analyses and mediation analyses of prenatal alcohol intake, smoking, gestational age, and birth weight. We report two independent gene-by-prenatal-stress interactions on DNAm after multiple testing correction, including five genetic variants in CHD2 and ORC5, and two DNAm sites in EPPK1. By comparison, the Gmodel showed 691,202 associations and the Emodel showed three associations in genes AHRR, GFI1, and MYO1G, which could largely explained by prenatal smoking. Genes linked to suggestive GxEmodel results were often involved in neuronal development. Our results provide some support of interaction of prenatal stress with the childs genome on DNAm of genes related to neuronal development. These results do not confirm the notion that gene-by-environment interaction models show more associations with DNAm compared to genes or the environment studied in isolation.

Correspondence in DNA methylation between blood and brain is known in humans. If this pattern is present in pig has not been examined. In this study, we profiled DNA methylation of blood from pigs at adult ages, and compared those with the methylation profiles of fetal brain. Neural network regression modeling showed specific methylations in the adult blood that can reliably predict methylation of the fetal brain. Genes associated with these predictive methylations included markers of specific cell types of blood and brain, in particular, markers of bone marrow hematopoietic progenitors, and glial cells primarily the ependymal and Schwann cells of brain. The results of this study show that developmental methylation changes of the brain during fetal stages are maintained as an epigenetic memory in the blood in adult life. Thus, pig models may be harnessed to uncover potential roles of epigenetic memory in brain health and diseases.

DNA methylation is a type of epigenetic modification known to exhibit fluctuations in response to environmental factors. The association of macrosocial factors, such as interpersonal mobility, on methylation has seldom been investigated. This study aimed to examine the association of relational mobility, defined as the extent to which individuals can form and replace social relationships, on the DNA methylation of oxytocin receptor genes. DNA was extracted from the buccal cells of 95 adult participants (50 men and 45 women) and subjected to microarray analysis of DNA methylation using Illumina EPIC v2.0. The findings indicate that the oxytocin receptor genes methylation level was higher in individuals residing in low relational mobility social environments. The CpG site associated with relational mobility is an enhancer region, indicating that social environments with low relational mobility exert a suppressive effect on the transcriptional efficiency of the oxytocin receptor gene. Significance StatementThe association between DNA methylation of the oxytocin receptor gene and relational mobility was examined in 95 adults in their 20s to 60s, and found that those living in social environments with lower levels of relationship mobility had higher rates of DNA methylation of the oxytocin receptor gene. This study is a novel approach to a problem discussed in the social sciences using new analytical techniques in epigenomics.

CpG methylation in genomic DNA is well known as a repressive epigenetic marker in eukaryotic transcription, and DNA methylation of the promoter regions is correlated with silencing of gene expression. In contrast to the promoter regions, the function of DNA methylation during transcription termination remains to be elucidated. A recent study has revealed that mouse DNA methyltransferase 3a (Dnmt3a) mainly functions in de novo methylation in the promoter and gene body regions (including transcription termination sites (TTSs)) during development. To investigate the relationship between DNA methylation overlapping the TTSs and transcription termination, we employed two strategies: informatic analysis using already deposited datasets of Dnmt3a-/- mouse cells and the zebrafish model system. Bioinformatic analysis using methylome and transcriptome data showed that hypomethylated differentially methylated regions overlapping the TTSs were associated with increased read counts and chimeric transcripts downstream of TTSs in Dnmt3a-/- Agouti-related protein neurons, but not in Dnmt3a-/- embryonic stem cells and mouse embryonic fibroblasts. We experimentally detected increased read-through and chimeric transcripts downstream of hypomethylated TTSs in zebrafish maternal-zygotic dnmt3aa-/- mutant. This study is the first to identify transcription termination defects in DNA hypomethylated TTSs in Dnmt3a-/- vertebrates.

DNA methylation is extensively reprogrammed during early stage of mammalian development and is essential for normal embryogenesis. It is well established that mouse embryos acquire genome-wide DNA methylation during implantation, referred to as de novo DNA methylation, from globally hypomethylated blastocysts. However, the fact that the main de novo DNA methyltransferase 3B (DNMT3B) is initially expressed as early as the 8-cell stage, contradicts the current knowledge about timing of initiation of de novo DNA methylation. Here, we reported that a previously overlooked minor wave of de novo DNA methylation initially occurs during the transition from the 8-cell to blastocyst stage, before the well-known large-scale de novo DNA methylation during implantation. Functional analyses indicated that minor de novo DNA methylation regulates proliferation, lineage differentiation and metabolic homeostasis of preimplantation embryos, and is critical for embryonic developmental potential and pregnancy outcomes. Furthermore, bioinformatic and functional analyses indicated that minor de novo DNA methylation preferentially occurs on the X chromosome and co-regulates imprinted X-chromosome inactivation via the interaction between DNMT3B and polycomb repressive complexes 2 core components during blastocyst formation. Thus, our study updates the current knowledge of embryonic de novo DNA methylation, thereby providing a novel insight of early embryonic epigenetic reprogramming. Summary statementA minor wave of de novo DNA methylation has been initiated prior to blastocyst formation, but not during the implantation period, and co-regulates imprinted X-chromosome inactivation.

Epigenetic regulations play important roles in cell fate determination during neurogenesis, a process by which different types of neurons are generated from neural stem and progenitor cells (NSPCs). Although some epigenetic changes are part of developmental and aging processes, the role of tri-methylation on histone 3 lysine 27 (H3K27me3) and histone 4 lysine 20 (H4K20me3) in primate hippocampal NSPCs remains elusive. This task is best assessed within a context resembling the human brain. As more studies emerge, the baboon represents an excellent model of human central nervous system in addition to their genomic similarity. With a focus on H3K27me3 and H4K20me3, the overarching goal of this work is to reveal their respective epigenetic landscapes in NSPCs of non-human primate baboon hippocampus. We identified putative targets of H3K27me3 and H4K20me3 that suggests a protective mechanism by dual H3K27me3/H4K20me3-mediated repression of specific-lineage gene activation important for differentiation processes while controlling the progression of the cell cycle.

The majority of existing DNA methylation (DNAm) studies have used peripheral surrogate tissues to research molecular mechanisms underlying brain-related traits. Epigenetic processes in the brain have yet to be fully elucidated by DNAm findings from peripheral tissues, as these processes are complex to disentangle from DNAm tissue- and cell type-specificity. Furthermore, distinct brain cell types play important roles in brain health and disease. Building on previous findings of high blood-brain correlations at some DNAm sites, we specifically aimed to 1) identify single DNAm sites associated with DNAm-estimated brain cell type proportions in both the frontal brain and peripheral blood, 2) to combine blood DNAm sites to predict brain cell type proportions through multivariate models, and 3) to examine the role of biological factors associated with blood DNAm, age and epigenetic age acceleration (EAA) on brain cell type proportions. Epigenome-wide association studies for seven distinct estimated brain cell type proportions in matched frontal brain and peripheral blood samples (n=104) revealed that [~]7% of brain cell type-associated DNAm sites had correlating DNAm levels in peripheral blood (p<0.05). Six DNAm sites in peripheral blood were associated with endothelial and stromal brain cell type proportions (False Discovery Rate<0.05). Brain cell type proportion predictions trained with machine learning approaches using peripheral blood DNAm showed a correlation (p<0.05) with microglia and astrocyte proportions estimated through cell deconvolution using brain DNAm. Estimated blood immune cell type proportions were significantly associated with estimated brain cell type proportions. Lastly, brain EAA was associated with different brain and blood cell types proportions (p<0.05). These results show that DNAm levels in peripheral blood can inform brain cell type proportions, even though DNAm patterns are tissue-specific. The correlations between DNAm profiles specific to immune cell types in blood and brain highlights the link between the peripheral immune system and immune functions in the central nervous system.

During dysregulated inflammation and sepsis, there is a sudden surge of cytokines, such as TNF alpha, IL6, and IL10, which disrupts the body homeostasis. This sudden and rapid increase in cytokine gene expression cannot be explained by the conventional central dogma mechanism. DNA methylation is one of the most significant epigenetic modifications. DNA methylation is mostly associated with the suppression of gene activity, and DNA demethylation is associated with the activation of gene activity. There are numerous transcription factors, such as CREB1, c-FOS, AP-1, IRF1, and EGR1, that play pivotal roles in regulating inflammation. Thus, it was hypothesized that changes in the DNA methylation patterns of cytokine promoter regions or in the promoter regions of these specific transcription factors might be the potential reasons for the increase in cytokine levels during sepsis. During endotoxin stimulation, DNA methyltransferases were suppressed, and DNA methylation levels were altered at the global level. Bisulfite sequencing revealed no change in the DNA methylation patterns of the TNF-alpha, IL6 and IL10 cytokine promoters. The CREB1 and c-FOS transcription factor promoters were demethylated after LPS stimulation and in clinical sepsis samples. Overall, this study highlights the importance of the role of DNA methylation in sepsis.

Gene body methylation is one of the most taxonomically widespread epigenetic marks, yet its function and evolutionary history are poorly understood. While there is a positive association between gene body methylation and gene expression in many organisms, the mechanisms behind this relationship are unclear. Here, we investigate the function of gene body methylation in the stick insect Timema cristinae. We compare patterns of genome-wide gene body methylation to gene expression, open chromatin peaks, and chromatin compartments. We find that 95% of genes with gene body methylation occur in open chromatin compartments (euchromatin). Furthermore, highly expressed genes are impoverished in methylation at their transcription start site (TSS), which is associated with a peak of open chromatin. These findings suggest that the positive correlation between gene body methylation and gene expression is due to chromatin compartment structure. Yet, methylation around the TSS is associated with gene expression, possibly playing an inhibitory role as in vertebrates. Lastly, comparative analysis of Apis mellifera reveals a similar relationship between methylation and chromatin compartments, but not gene expression. These results suggest a possible explanation for the heterogeneous association between gene body methylation and gene expression and give insight into DNA methylations role in regulating gene expression.

The Illumina Infinium MethylationEPIC v2.0 BeadChip (EPICv2 array) is a microarray for assessment of the human epigenome. Sites on the EPICv2 array are annotated with an open-source file provided by Illumina, the EPICv2 manifest. Of the 923,452 unique genomic sites targeted by the EPICv2 array, the Illumina manifest identifies just 214,808 as mapping to a gene, excluding many sites located within a gene body. Based on the genomic coordinates of probes, we have mapped each site assayed on the Illumina EPICv2 array using publicly available data, comprehensively annotating affiliated genes and regulatory elements. We have found that a total of 700,392 EPICv2 array sites are located within a gene body (exon, intron, or UTR) according to the GENCODE Human release 47 (GENCODEv47) database. 509,940 of these sites were not annotated as being within a gene in the Illumina EPICv2 manifest, primarily because the Illumina manifest does not annotate introns - 498,407 of the excluded sites, or 97.74%, are located within the intron of at least one transcript. The Illumina EPICv2 manifest annotates 358,539 sites as being within 1500bp of a transcription start site (TSS). Using a distance-based approach, we have labelled 267,183 sites as being within promoter distance of a gene (<1500bp upstream or <500bp downstream of the TSS), and 140,123 sites as being within enhancer distance (1501-5000bp upstream of the TSS, excluding sites located within a gene body). We re-annotated the EPICv2 manifest using GENCODEv47 data to label intragenic features, and a distance-based approach to label the regulatory genome. We also include a column indicating whether a site is located in any promoter or enhancer, according to the GeneHancer database. The re-annotated manifest additionally labels which sites are required for the Horvath DNA Methylation Age Calculator and MethylDetectR epigenetic clocks, to facilitate data preparation for these tools. In conclusion, we have re-annotated the EPICv2 manifest, allowing more complete assessment of EPICv2 sites associated with gene bodies and regulatory regions during the interpretation of epigenetic studies. The re-annotated manifest is publicly available - see the Data Availability section of this article.

DNA methylation within CpG islands is a key epigenetic mechanism regulating gene expression. SHANK3 encodes a synaptic scaffolding protein essential for neurodevelopment and synaptic function, and aberrant SHANK3 methylation has been implicated in neuropsychiatric disorders. To enable reliable locus-specific investigation of SHANK3 epigenetic regulation, we developed a high-resolution melting (HRM) assay. In silico screening identified a CpG-rich region upstream of exon 3 as the most suitable locus for assay design. Bisulfite-converted sequences representing fully methylated and unmethylated states were used to generate three primer sets, of which two successfully amplified the target region and produced distinct melting profiles discriminating methylated from unmethylated templates. The assay was optimized on two HRM platforms (LightCycler(R) 480 and CFX96), and conversion efficiency was confirmed with commercial control DNAs. This locus-specific HRM assay provides a methodological framework for qualitative SHANK3 methylation analysis and represents a promising tool for future validation studies and potential clinical investigations in neurodevelopmental and neuropsychiatric disorders.

Apart from DNA-sequence-based inheritance, inheritance of epigenetic marks such as DNA methylation is controversial across the tree of life. In mammals, post-fertilization and primordial germ cell reprogramming processes erased most parental DNA methylation information. In nonmammalian vertebrates and insects, it has been proposed that DNA methylation is an essential hereditary carrier. However, how and to what extent general DNA methylation reprogramming affects intergenerational inheritance in molluscs remains unclear. Here, we investigated genome-wide DNA methylation in a mollusc model, the Pacific oyster (Crassostrea gigas), to test how epigenetic information transfers from parents to offspring. Analysis of global methylome revealed that the DNA methylation patterns are highly conserved within families. Almost half of the differentially methylated CpG dinucleotides (DMCs) between families in parents could transfer to offspring. These results provided the direct evidence for the hypothesis that the Pacific oyster DNA methylation patterns are inherited in generations. Moreover, distinct DNA methylation differences between male and female somatic tissues in C. gigas are revealed in this study. These sex-differential methylated genes significantly enriched in the regulation of Rho protein signal transduction process, which indicated that DNA methylation might have an essential role in the sexual differentiation of somatic tissues in C. gigas. Author SummaryTransgenerational inheritance of DNA methylation marks varies across the tree of life. In mammals, post-fertilization and primordial germ cell reprogramming processes obstructed the DNA methylation transmission from parents to child, and only some CpG dinucleotides retain gamete-inherited methylation. However, the DNA methylation inheritance seems apparent in nonmammalian vertebrates and insects. As one of the essential mollusc models, the Pacific oyster Crassostrea gigas have received the most substantial epigenetic studies, mainly focusing on the DNA methylation profiles. While a previous study suggested the existence of paternal inheritance of DNA methylation patterns in C. gigas, more data are needed to confirm this hypothesis. In this study, genome-wide DNA methylation analysis was performed to investigate the epigenetic inheritance in C. gigas. Almost half of the DNA methylation differences between families in parents were found to be transferred to children, indicating the absence of global DNA methylation reprogramming in C. gigas. Besides, extensive hypomethylation in C. gigas females compared with males were also unveiled. These hypomethylated genes were significantly enriched in the regulation of Rho protein signal transduction process. For example, guanine nucleotide exchange factors, including KALRN, FGD1, and FGD6, were hypomethylated in C. gigas females, and the corresponding transcriptions were significantly upregulated. Our findings provided insights into the evolution of DNA methylation patterns, transgenerational epigenetic inheritance, and sexual differentiation in molluscs.

Wellbeing is associated with both behavioral phenotypes as well as several key life outcomes, such as health, employment, and coping with stressful events. These phenotypes associated with wellbeing could be potential indicators of differential epigenetic patterns between individuals that differ in their levels of wellbeing. We performed the largest epigenome-wide (EWAS) meta-analysis of wellbeing to date by combining whole blood DNA methylation data (Illumina 450k array) from 13 cohorts from Europe, Australia, and the USA (N = 10,757 participants). After correcting for smoking and BMI, no epigenome-wide significant methylation sites were identified. We tested whether a weighted methylation score (MS) based on leave-one-cohort-out EWAS meta-analysis summary statistics predicted wellbeing in an independent cohort, and whether prediction was significant over and above the polygenic score (PGS) for wellbeing. The MS was associated with wellbeing (variance explained=0.22%, p=0.03) and was no longer significant after adding the polygenic score (PGS; variance explained=0.43%, p=0.0046, MS; variance explained=0.07%, p=0.2842). We further compared DNA methylation levels in 16 pairs of monozygotic twins discordant for wellbeing. These analyses revealed no significant within-pair DNA methylation differences at the top-sites from the meta-analysis or in MS. Our results suggest that larger EWAS meta-analyses with uniform phenotype assessment are required to identify methylation sites associated with wellbeing.

Interindividual genetic variability is well characterised, but we still lack a complete catalogue of loci displaying variable and stable epigenetic patterns. Here, we report a catalogue of stable and variable interindividual DNA methylation in human whole blood by analysing the DNA methylation patterns in 3642 individuals using the IlluminaEPIC array. Our results showed that 41,216 CpGs display stable methylation (SMPs) and 34,972 CpGs display variable methylation levels (VMPs). This catalogue will be a useful resource for interpretation of results when associating epigenetic signals to phenotypes. We observed that SMPs are highly enriched in CpG islands, depleted at CpG shelves and open sea regions of the genome. In addition, we found that the VMPs were under higher genetic control than the SMPs and that trans mQTL pairs are often located in the same TAD or connected by chromatin loops. A subset of these VMPs (784) were classified as putative epialleles and our results demonstrate that these loci located in regulatory regions exhibit a link with gene expression.

ObjectiveExposure to cigarette smoking during pregnancy has been robustly associated with cord blood DNA methylation. However, little is known about such effects on the placenta; in particular, whether cigarette smoking before pregnancy could also induce epigenetic alterations in the placenta of former smokers is unknown. Design and resultsPlacental DNA methylation levels were measured in 568 women and compared among non-smokers and women either smoking during their pregnancy or who had ceased smoking before pregnancy. An Epigenome Wide Association Study identified 344 Differentially Methylated Regions (DMRs) significantly associated with maternal smoking status. Among these 344 DMRs, 262 showed "reversible" alterations of DNA methylation, only present in the placenta of current smokers, whereas 44 were also found altered in former smokers, whose placenta had not been exposed directly to cigarette smoking. This observation was further supported by a significant demethylation of LINE-1 sequences in the placentas of both current (-0.43 (-0.83 to -0.02)) and former smokers (-0.55 (-1.02 to -0.08)) compared to nonsmokers. A comparative analysis of the epigenome landscape based on the ENCODE placenta data demonstrated an enrichment of all 344 DMRs in enhancers histone marks. Additionally, smoking-associated DMRs were found near and/or overlapping with 13 imprinting gene clusters encompassing 18 imprinted genes. ConclusionsDNA methylation patterns alterations were found in 344 genomic regions in the placenta of women smoking during their pregnancy, including 44 DMRs and LINE-1 elements, where methylation changes persisted in former smokers, supporting the hypothesis of an "epigenetic memory" of exposure to cigarette smoking before pregnancy. Enhancers regions, including imprinting control regions were also particularly affected by placenta methylation changes associated to smoking, suggesting a biological basis for the sensitivity of these regions to tobacco exposure and mechanisms by which fetal development could be impacted.

Despite the improvements in tool development for DNA methylation analysis, there is a lack of a consensus on computational and statistical models used for differentially methylated cytosine (DMC) identification. This variability complicates the interpretation of findings and raises concerns about the reproducibility and biological significance of the detected results. In this regard, the primary objective of this study was to compare the performance, concordance, and biological relevance of edgeR and methylKit tools in detecting DMCs (the first one based on fold change and the second one based on percentage), following morphine exposure model in mouse embryonic stem cells (mESCs). While a different number of total DMCs was identified by each tool, both pipelines detected a global hypomethylation as a result. Genomic analysis revealed a predominant distribution of DMCs in intergenic and intronic regions on one hand, and in open sea regions on the other hand. Despite the differences in sensitivity, both tools demonstrated moderate concordance in DMCs detection ([~]56%) and high concordance in gene level analysis ([~]90%), identifying similar differentially methylated genes (DMGs). Overall, the results underscore the complementary strengths of methylKit and edgeR and highlight the importance of tool selection for epigenetic studies. As a conclusion, integrating both pipelines is recommended for comprehensive analysis, particularly in studies with complex experimental designs.

Bisulfite sequencing has long been considered the gold standard for measurement of DNA methylation at single CpG resolution. In the meantime, several new approaches have been developed, which are regarded as less error-prone. Since these errors were shown to be sequence-specific, we aimed to verify the methylation data of a particular region of the TRPA1 promoter obtained from our previous studies. For this purpose, we compared methylation rates obtained via direct bisulfite sequencing and nanopore sequencing. Thus, we were able to confirm our previous findings to a large extent.

BackgroundEpigenome studies of human HIV-1 (HIV) in whole blood have uncovered a growing list of differentially methylated genes associated with either HIV acquisition, disease progression, or both. Cocaine use is associated with increased disease severity, and methylation changes in some of the HIV-associated genes mediate this effect. Many of these genes are critical players in innate immune response, including both regulators and targets of interferon-alpha and NF-kB activation. However, no study to date has evaluated the gene expression dynamics for these genes in the context of HIV. MethodsTargeted gene expression analyses were performed on 588 people who used illicit drugs within a harmonized cohort comprised of the Vancouver People Who Inject Drugs Study (VPWIDS) using RNAseq in whole blood, including 227 people living with HIV (PLWH). Eighteen genes were selected from six recent epigenome-wide association studies to test for differential expression by HIV status. Both gene-level and transcript-level expression changes were estimated using negative binomial regression models. ResultsNine of the 18 target genes exhibited significant upregulation in PLWH after multiple hypothesis testing correction: EPSTI1, IFI44L, IFIT3, MX1, NLRC5, PARP9, PLSCR1, RIN2, and RSAD2. Transcript-level analysis detected additional upregulation of isoforms for genes CD44, RASSF3, and TAP1. Stratified analysis by cocaine use revealed MX1 and RSAD2 to be exclusively upregulated among PLWH who recently used cocaine. Pathway analysis identified significant dysregulation in the interferon alpha/beta signaling pathway. ConclusionsWe confirm the dysregulation of genes previously reported to have differential methylation among PLWH. Results from this study support the model of epigenetic changes altering gene expression for key immune genes such as NLRC5 and MX1, and demonstrate systemic dysregulation of genes involved in innate immune function.

BackgroundRibosomal DNA (rDNA) transcription by the RNA polymerase I (Pol I) is a rate-limited step for ribosome synthesis, which is critical for cell growth, cell differentiation, and tumorigenesis. Meanwhile rDNA transcription is modulated by DNA methylation and histone epigenetic modification. Though with great progress in epigenetic research recently, it still remains much uncertain about the relationship of histone variant epigenetic modification and rDNA transcription.\n\nResultsIn this study, epigenetic profiles of silent rDNA in next-generation sequencing datasets were examined. We found that the chaperone of histone variant H3.3, the alpha-thalassemia/mental retardation X-linked syndrome protein (ATRX)/death domain-associated protein (DAXX) complex, and methyltransferase SET domain bifurcated 1 (Setdb1, also known as ESET) help maintain H3.3K9me3 modifications among the promoter and coding regions of silent rDNA. Our experiments further confirmed that DAXX depletion leads to the conversion of silent rDNA into upstream binding factor-bound active rDNA and the release of rDNA transcriptional potency. Support for this model is provided by data from a low-grade glioma in which ATRX is lost and a higher level of ribosomal biosynthesis, nucleolus activity, and proliferation are observed.\n\nConclusionsWe demonstrate a model of epigenetic regulation for rDNA with roles for the ATRX/DAXX complex and H3.3/H3K9me3 modifications identified. Thus, loss of ATRX/DAXX may represent a driving force for tumorigenesis due to its contribution to the release of rDNA transcriptional potency.

Antenatal corticosteroids (ACS) are provided to improve perinatal survival when there is risk of preterm birth. Though evidence suggests increased risk of developing neurobehavioural disorders in exposed offspring, the mechanisms that mediate this relationship remain largely unknown. Here, we investigated the DNA methylation patterns in the prefrontal cortex (PFC) of exposed offspring. We hypothesized that differential methylation will be evident at both newborn and juvenile ages. Pregnant guinea pigs were administered saline or betamethasone (1mg/kg) on gestational days 50/51 to mimic a single course of ACS. gDNA was isolated from the PFC of term-born offspring on postnatal day 1 (PND1) and PND14 to identify differentially methylated CpG sites (DMCs) using reduced representative bisulfite sequencing. In the PND1 PFC, 1521 DMCs, annotating to 145 genes were identified following ACS. Identified genes were involved in pathways regulating developmental cellular process. In the PND14 PFC, 776 DMCs representing 46 genes were identified, and were enriched in synaptic signalling pathways. Though no individual DMCs were identified at both PND1 and PND14, differential methylation was consistently observed at the binding sites of transcription factors PLAGL1, TFAP2C, ZNF263, and SP1 at both ages. In this study, we identified an altered DNA methylome in the PFC of ACS-exposed guinea pig offspring at both newborn and juvenile ages. Notably, a unique methylation signature was consistently observed at four key transcription factor binding sites at multiple post-natal time points, indicating a persistent change which may predispose the development of altered neurobehavioural phenotypes that have been described in exposed offspring.