Differences In DNA Methylation Profiles Research Articles

Randomized dose-response trial of n-3 fatty acids in hormone receptor negative breast cancer survivors- impact on breast adipose oxylipin and DNA methylation patterns.

Increasing evidence suggests the unique susceptibility of estrogen receptor and progesterone receptor negative (ERPR-) breast cancer to dietary fat amount and type. Dietary n-3 polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), may modulate breast adipose fatty acid profiles and downstream bioactive metabolites to counteract pro-inflammatory, pro-carcinogenic signaling in the mammary microenvironment. To determine effects of ~1 to 5 g/d EPA+DHA over 12 months on breast adipose fatty acid and oxylipin profiles in women with ERPR(-) breast cancer, a high-risk molecular subtype. We conducted a 12-month randomized controlled, double-blind clinical trial of ~5g/d vs ~1g/d DHA+EPA supplementation in women within 5 years of completing standard therapy for ERPR(-) breast cancer Stages 0-III. Blood and breast adipose tissue specimens were collected every 3 months for biomarker analyses including fatty acids by gas chromatography, oxylipins by LC-MS/MS, and DNA methylation by reduced-representation bisulfite sequencing (RRBS). A total of 51 participants completed the 12-month intervention. Study treatments were generally well-tolerated. While both doses increased n-3 PUFAs from baseline in breast adipose, erythrocytes, and plasma, the 5g/d supplement was more potent (n =51, p <0.001). The 5g/d dose also reduced plasma triglycerides from baseline (p =0.008). Breast adipose oxylipins at 0, 6, and 12 months showed dose-dependent increases in unesterified and esterified DHA and EPA metabolites (n =28). Distinct DNA methylation patterns in adipose tissue after 12 months were identified, with effects unique to the 5g/d dose group (n =17). Over the course of 1 year, EPA+DHA dose-dependently increased concentrations of these fatty acids and their derivative oxylipin metabolites, producing differential DNA methylation profiles of gene promoters involved in metabolism-related pathways critical to ERPR(-) breast cancer development and progression. These data provide evidence of both metabolic and epigenetic effects of n-3 PUFAs in breast adipose tissue, elucidating novel mechanisms of action for high-dose EPA+DHA-mediated prevention of ERPR(-) breast cancer.

Global endometrial DNA methylation analysis reveals insights into mQTL regulation and associated endometriosis disease risk and endometrial function

Endometriosis is a leading cause of pain and infertility affecting millions of women globally. Herein, we characterize variation in DNA methylation (DNAm) and its association with menstrual cycle phase, endometriosis, and genetic variants through analysis of genotype data and methylation in endometrial samples from 984 deeply-phenotyped participants. We estimate that 15.4% of the variation in endometriosis is captured by DNAm and identify significant differences in DNAm profiles associated with stage III/IV endometriosis, endometriosis sub-phenotypes and menstrual cycle phase, including opening of the window for embryo implantation. Menstrual cycle phase was a major source of DNAm variation suggesting cellular and hormonally-driven changes across the cycle can regulate genes and pathways responsible for endometrial physiology and function. DNAm quantitative trait locus (mQTL) analysis identified 118,185 independent cis-mQTLs including 51 associated with risk of endometriosis, highlighting candidate genes contributing to disease risk. Our work provides functional evidence for epigenetic targets contributing to endometriosis risk and pathogenesis. Data generated serve as a valuable resource for understanding tissue-specific effects of methylation on endometrial biology in health and disease.

No association between war-related trauma or PTSD symptom severity and epigenome-wide DNA methylation in Burundian refugees

ABSTRACT Background: War-related trauma is associated with varying posttraumatic stress disorder (PTSD) prevalence rates in refugees. In PTSD development, differential DNA methylation (DNAm) levels associated with trauma exposure might be involved in risk versus resilience processes. Studies investigating DNAm profiles related to trauma exposure and PTSD among refugees remain sparse. Objective: The present epigenome-wide association study investigated associations between war-related trauma, PTSD, and altered DNAm patterns in Burundian refugee families with 110 children and their 207 female and male caregivers. Method: War-related trauma load and PTSD symptom severity were assessed in structured clinical interviews with standardised instruments. Epigenome-wide DNAm levels were quantified from buccal epithelia using the Illumina EPIC beadchip. Results: Controlling for biological confounders, no significant epigenome-wide DNAm alterations associated with trauma exposure or PTSD were identified in children or caregivers (FDRs > .05). Co-methylated positions derived as modules from weighted gene correlation network analyses were not significantly associated with either war-related trauma experience in children or caregivers or with PTSD. Conclusions: These results do not provide evidence for altered DNAm patterns associated with exposure to war-related trauma or PTSD.

Detailed molecular and pathological analyses of primary intracranial embryonal rhabdomyosarcoma with a BRAF mutation: illustrative case.

The etiological significance of the RAS and PI3K pathways has been reported in systemic embryonal rhabdomyosarcoma (ERMS) but not in primary intracranial ERMS (PIERMS). Herein, the authors present a unique case of PIERMS with a BRAF mutation. A 12-year-old girl with progressive headache and nausea was diagnosed with a tumor in the right parietal lobe. Semi-emergency surgery revealed an intra-axial lesion that was histopathologically identical to an ERMS. Next-generation sequencing indicated a BRAF mutation as a pathogenic variation, but the RAS and PI3K pathways showed no alteration. Although there is no established reference class for PIERMS, the DNA methylation prediction was closest to that of ERMS, indicating the possibility of PIERMS. The final diagnosis was PIERMS. The patient underwent local radiotherapy (50.4 Gy) and multiagent chemotherapy, with no recurrence for 12 months after surgery. This may be the first case demonstrating the molecular features of PIERMS, especially the intra-axial type. The results showed a mutation in BRAF but not in the RAS and PI3K pathways, which is different from the existing ERMS features. This molecular difference may cause differences in DNA methylation profiles. Accumulation of the molecular features of PIERMS is necessary before any conclusions can be drawn.

Analysis of core mutation and TET2/ASXL1 mutations DNA methylation profile in myelodysplastic syndrome

ABSTRACTObjectivesThe study aims to analyze genetic mutation and clinical characteristics and study their correlation with survival prognosis of patients with myelodysplastic syndromes (MDS). Moreover, the differential DNA methylation profiles between TET2 mutated (Mut)/ASXL1 wild-type (WT) and TET2-Mut/ASXL1-Mut MDS samples were investigated to explore the mechanism of MDS patients with TET2/ASXL1 mutations.MethodsThe clinical data of 195 patients diagnosed with MDS were selected and statistically analyzed. The DNA methylation sequencing data set was obtained from the GEO and bioinformatics analyzed.ResultsOf the 195 MDS patients, 42 (21.5%) carried TET2 mutations. 81% of TET2-Mut patients could detect comutated genes. The most commonly comutated gene in MDS patients with TET2-Mut was ASXL1, which had a tendency towards poorer prognosis (P = 0.08). GO analysis showed that highly methylated differentially methylated genes (DMGs) was mainly enriched in biological processes such as cell surface receptor signal pathway and cell secretion. Hypomethylated DMGs was mainly enriched in cell differentiation and cell development. KEGG analysis showed that hypermethylated DMGs was mainly enriched in Ras signal pathway and MAPK signal pathway. Hypomethylated DMGs was mainly enriched in extracellular matrix receptor interaction and focal adhesion. PPI network analysis identified 10 hub genes of hypermethylated and hypomethylated DMGs that may be associated with patients with TET2-Mut/ASXL1-Mut respectively.ConclusionsOur results illustrate the interrelationships between genetic mutations and clinical phenotypes and disease outcomes, with substantial potential for clinical application. Differentially methylated hub genes might represent potential biomarkers and provide novel insights and possible targets for MDS with double TET2/ASXL1 mutations.

Validation of Myc-Associated Protein X (MAX) regulation in growth hormone secreting and nonfunctional pituitary adenoma.

Many patients with growth hormone-secreting pituitary adenoma (GHPA) fail to achieve biochemical remission, warranting investigation into epigenetic and molecular signatures associated with tumorigenesis and hormonal secretion. Prior work exploring the DNA methylome showed Myc-Associated Protein X (MAX), a transcription factor involved in cell cycle regulation, was differentially methylated between GHPA and nonfunctional pituitary adenoma (NFPA). We aimed to validate the differential DNA methylation and related MAX protein expression profiles between NFPA and GHPA. DNA methylation levels were measured in 52 surgically resected tumors (37 NFPA, 15 GHPA) at ~100,000 known MAX binding sites derived using ChIP-seq analysis from ENCODE. Findings were correlated with MAX protein expression using a constructed tissue microarray (TMA). Gene ontology analysis was performed to explore downstream genetic and signaling pathways regulated by MAX. GHPA had more hypomethylation events across all known MAX binding sites. Of binding sites defined using ChIP-seq analysis, 1,551 sites had significantly different methylation patterns between the two cohorts; 432 occurred near promoter regions potentially regulated by MAX, including promoters of TNF and MMP9. Gene ontology analysis suggested enrichment in genes involved in oxygen response, immune system regulation, and cell proliferation. Thirteen MAX binding sites were within coding regions of genes. GHPA demonstrated significantly increased expression of MAX protein compared to NFPA. GHPA have significantly different DNA methylation and downstream protein expression levels of MAX compared to NFPA. These differences may influence mechanisms involved with cellular proliferation, tumor invasion and hormonal secretion.

Identification of novel genetic and epigenetic regulators of different tissue types of cervical cancer.

The study aimed to find differential gene mutations, DNA methylation, and expression profiles among different categories of cervical cancer samples. The study was based on freely available gene mutations, promoter methylation, and gene expression status of The Cancer Genome Atlas (TCGA) cervical cancer samples and adjacent normal tissues in the Genomic Data Commons (GDC) portal. The association of CpG island methylation with gene expression was determined through negative correlation analysis. We identified that the ErbB signaling pathway and proteoglycans pathway was significantly associated with adenocarcinoma cervical cancers patients. In these pathways, missense mutation especially S310F in the ERBB2 gene as well as G12D and A146T in the KRAS gene were significantly associated with adenocarcinoma cases. Furthermore, a comparison of SCC cases with adjacent control tissues revealed differential hypermethylation of two CpG positions of the KAAG1 gene and differential downregulation of NPY1R and NPY5R genes in cervical squamous cell carcinoma compared to cervical adenocarcinoma cases and adjacent normal tissues. Specifically, the hypermethylation of the promoter region of the KAAG1 gene might be responsible for the carcinogenesis of cervical squamous cells exclusively and methylation marks can be reversible by the widely used drug, azacytidine. In contrast, adenocarcinoma cervical cancer cases may be treated with floxuridine which is successfully utilized for other tissue-specific adenocarcinoma cases. These results provide valuable insight into the differential molecular markers among the categories of cervical cancer, which helps our ability to classify these cancers and for targeted therapy.

P11.27.B Whole genome DNA methylation as predictive biomarker in CNS WHO grade 2 and 3 oligodendroglioma patients receiving early postoperative treatment

Abstract Background Oligodendrogliomas are glial tumors with a relatively favorable survival prognosis of &amp;gt;10 years. While immediate postoperative treatment prolongs survival, long-term toxicities of adjuvant radio-chemotherapy remain a concern. Predictive biomarkers guiding postoperative treatment decisions are limited. Material and Methods In this retrospective study, we included patients treated for a newly diagnosed oligodendroglioma (isocitrate dehydrogenase (IDH)-mutated, 1p/19q-codeleted, CNS WHO grades 2 and 3) in 1992 - 2019 at the Medical University of Vienna or the Kepler University Hospital Linz (Austria). Early treatment was defined as radiotherapy, chemotherapy, or both within 6 months after resection, whereas benefit from early treatment was defined as progression-free survival (PFS) above the median in the overall cohort. DNA methylation analysis was performed using Illumina MethylationEPIC 850k microarrays. Results Of all 201 eligible patients, sufficient tumor tissue for DNA methylation analysis was available in 46 patients. Of these, 25/46 (54.3%) were diagnosed with CNS WHO grade 2 and 21/46 (45.6%) with grade 3 oligodendroglioma. Median age at diagnosis was 41 years (range: 23-70). In total, 21/46 (45.6%) patients received early treatment, of whom 13/21 (61.9%) received radio-chemotherapy, 6/21 (28.6%) radiotherapy only and 2/21 (9.5%) chemotherapy only. Median PFS was 134.0 months (95%CI: 78.3 - not reached) in patients receiving early treatment versus 87.2 months (95%CI: 66.8 - 150) in patients who did not. In patients receiving early treatment, differences in DNA methylation profiles could be detected between patients who drew benefit from postoperative treatment (group 1) versus those who did not (group 2). Based on the top 1000 differentially methylated CpG sites between both groups, two clusters were detected which comprised either patients of group 1 or 2. Clustering was independent from gender, WHO grade, extent of resection, type of postoperative treatment, treating center, and O6-methylguanine-methyltransferease (MGMT) promoter methylation status. Gene set enrichment analysis of the top 1000 differentially methylated gene sites mapped to 694 genes showed differential methylation in genes involved in fibroblast growth receptor 1 (FGFR1) signaling, Wnt signaling, integrin signaling, and actin cytoskeleton regulation. Conversely, in patients not receiving early treatment, PFS did neither correlate with DNA methylation clustering nor with MGMT promoter methylation. Conclusion In our cohort, whole genome DNA methylation was associated with PFS in patients who received early postoperative treatment, suggesting a predictive but not prognostic role. As the predictive value of MGMT promoter methylation is limited in oligodendroglioma, whole genome DNA methylation should be considered in future clinical trials.

Enrichment of genomic pathways based on differential DNA methylation profiles associated with knee osteoarthritis pain

Our study aimed to identify differentially methylated regions (i.e., genomic region where multiple adjacent CpG sites show differential methylation) and their enriched genomic pathways associated with knee osteoarthritis pain (KOA). We recruited cognitively healthy middle to older aged (age 45–85) adults with (n = 182) and without (n = 31) self-reported KOA pain. We also extracted DNA from peripheral blood that was analyzed using MethylationEPIC arrays. The R package minfi (Aryee et al., 2014) was used to perform methylation data preprocessing and quality control. To investigate biological pathways impacted by differential methylation, we performed pathway enrichment analysis using Ingenuity Pathway Analysis (IPA) to identify canonical pathways and upstream regulators. Annotated genes within ± 5 kb of the putative differentially methylated regions (DMRs, p < 0.05) were subjected to the IPA analysis. There was no significant difference in age, sex, study site between no pain and pain group (p > 0.05). Non-Hispanic black individuals were overrepresented in the pain group (p = 0.003). At raw p < 0.05 cutoff, we identified a total of 19,710 CpG probes, including 13,951 hypermethylated CpG probes, for which DNA methylation level was higher in the groups with highest pain grades. We also identified 5,759 hypomethylated CpG probes for which DNA methylation level was lower in the pain groups with higher pain grades. IPA revealed that pain-related DMRs were enriched across multiple pathways and upstream regulators. The top 10 canonical pathways were linked to cellular signaling processes related to immune responses (i.e., antigen presentation, PD-1, PD-L1 cancer immunotherapy, B cell development, IL-4 signaling, Th1 and Th2 activation pathway, and phagosome maturation). Moreover, in terms of upstream regulators, NDUFAF3 was the most significant (p = 8.6E-04) upstream regulator. Our findings support previous preliminary work suggesting the importance of epigenetic regulation of the immune system in knee pain and the need for future work to understand the epigenetic contributions to chronic pain.

Establishment of DNA Methylation Profile Associated with TCM Syndrome in Endometriosis.

Objectives To screen the potential epigenetic biomarkers associated with endometriosis (EMS) and traditional Chinese medicine (TCM) syndrome EMS types. Methods A cohort of 99 participants comprising 42 EMS patients with cold coagulation blood stasis (CCBS) syndrome, 35 EMS patients with Qi stagnation blood stasis (QSBS) syndrome, and 22 women of childbearing age without EMS were recruited. Reduced representation bisulfite sequencing (RRBS) was used to establish the differential DNA methylation profiles in human peripheral blood samples obtained from four non-EMS and four EMS patients with CCBS or QSBS syndrome, respectively. Differentially expressed genes (DEGs) were verified in 18 non-EMS, 38 CCBS-EMS, and 31 QSBS-EMS using pyrosequencing. Results Methylation sites of 123942, 127229, and 115961 were found in peripheral blood DNA of non-EMS, CCBS-EMS, and QSBS-EMS patients, respectively. GO and KEGG analyses showed that the pathological process of EMS may be closely related to the nervous system development, cell junctions, GABA-gated chloride ion channel activity, nicotine addiction, Hippo signaling pathway, mRNA surveillance pathway, and Wnt signaling pathway. The methylation level at CpG site within HDAC6 gene in QSBS-EMS patients was significantly different from that in control women. Conclusions The changes in DNA methylation in peripheral blood samples may be associated with EMS and TCM syndrome EMS types. The methylation level of HDAC6 gene may be used to distinguish QSBS-EMS patients from women without EMS.

Epigenomic profiling indicates a role for DNA methylation in the postnatal liver and pancreas development of giant pandas

Giant pandas are unique within Carnivora with a strict bamboo diet. Here, the epigenomic profiles of giant panda liver and pancreas tissues collected from three important feeding stages were investigated using BS-seq. Few differences in DNA methylation profiles were exhibited between no feeding and suckling groups in both tissues. However, we observed a tendency toward a global loss of DNA methylation in the gene-body and promoter region of metabolism-related genes from newborn to adult. Correlation analysis revealed a significant negative correlation between the changes in methylation levels within gene promoters and gene expression. The majority of genes related to nutrition metabolism had lost DNA methylation with increased mRNA expression in adult giant pandas. The few galactose metabolism and unsaturated fatty acid metabolism related genes that were hypomethylated and highly-expressed at early stages of giant panda development may meet the nutritional requirement of this species' highly altricial neonates.

Saliva cell type DNA methylation reference panel for epidemiological studies in children

ABSTRACT Saliva is a widely used biological sample, especially in pediatric research, containing a heterogenous mixture of immune and epithelial cells. Associations of exposure or disease with saliva DNA methylation can be influenced by cell-type proportions. Here, we developed a saliva cell-type DNA methylation reference panel to estimate interindividual cell-type heterogeneity in whole saliva studies. Saliva was collected from 22 children (7–16 years) and sorted into immune and epithelial cells, using size exclusion filtration and magnetic bead sorting. DNA methylation was measured using the Illumina MethylationEPIC BeadChip. We assessed cell-type differences in DNA methylation profiles and tested for enriched biological pathways. Immune and epithelial cells differed at 181,577 (22.8%) DNA methylation sites (t-test p < 6.28 × 10−8). Immune cell hypomethylated sites are mapped to genes enriched for immune pathways (p < 3.2 × 10−5). Epithelial cell hypomethylated sites were enriched for cornification (p = 5.2 × 10−4), a key process for hard palette formation. Saliva immune and epithelial cells have distinct DNA methylation profiles which can drive whole-saliva DNA methylation measures. A primary saliva DNA methylation reference panel, easily implemented with an R package, will allow estimates of cell proportions from whole saliva samples and improve epigenetic epidemiology studies by accounting for measurement heterogeneity by cell-type proportions.

1,25-dihydroxyvitamin D3 induces stable and reproducible therapeutic tolerogenic dendritic cells with specific epigenetic modifications

Autologous, antigen-specific, tolerogenic dendritic cells (tolDCs) are presently assessed to reverse and possibly cure autoimmune diseases such as type 1 diabetes (T1D). Good Manufacturing Practice production and clinical implementation of such cell therapies critically depend on their stability and reproducible production from healthy donors and, more importantly, patient-derived monocytes. Here the authors demonstrate that tolDCs (modulated using 1,25-dihydroxyvitamin D3 and dexamethasone) displayed similar features, including protein, transcriptome and epigenome profiles, between two international clinical centers and between T1D and healthy donors, validating reproducible production. In addition, neither phenotype nor function of tolDCs was affected by repeated stimulation with inflammatory stimuli, underscoring their stability as semi-mature DCs. Furthermore, tolDCs exhibited differential DNA methylation profiles compared with inflammatory mature DCs (mDCs), and this was already largely established prior to maturation, indicating that tolDCs are locked into an immature state. Finally, approximately 80% of differentially expressed known T1D risk genes displayed a corresponding differential DNA methylome in tolDCs versus mDCs and metabolic and immune pathway genes were also differentially methylated and expressed. In summary, tolDCs are reproducible and stable clinical cell products unaffected by the T1D status of donors. The observed stable, semi-mature phenotype and function of tolDCs are exemplified by epigenetic modifications representative of immature-stage cells. Together, the authors’ data provide a strong basis for the production and clinical implementation of tolDCs in the treatment of autoimmune diseases such as T1D.

Differential DNA Methylation Profiles in Patients with Temporal Lobe Epilepsy and Hippocampal Sclerosis ILAE Type I.

Hippocampal sclerosis (HS) is one of the most prevalent pathological types of temporal lobe epilepsy (TLE), and it significantly affects patient prognoses. The methylation of DNA plays an important role in the development of epilepsy. However, few studies have focused on HS subtypes to determine DNA methylation profiles in TLE. This study aimed to determine the pathogenesis of TLE from an epigenetic perspective in patients with TLE-HS type I (TLE-HSTI) and TLE without HS (TLE-nHS) using whole-genome bisulfite sequencing (WGBS). We defined 1171 hypermethylated and 2537 hypomethylated regions and found 632 differentially methylated genes (DMG) in the promoter region that were primarily involved in the regulation of various aspects of epilepsy development. Twelve DMG overlapped with differentially expressed genes (DEG) in the promoter region, and RT-qPCR findings revealed significant overexpression of the SBNO2, CBX3, RASAL3, and TMBIM4 genes in TLE-HSTI. We present the first systematic analysis of methylation profiles of TLE-HSTI and TLE-nHS from an epigenetic perspective using WGBS. Overall, our preliminary data highlight the underlying mechanism of TLE-HSTI, providing a new perspective for guiding treatment of TLE.

DNA methylation profiles in adults born at extremely low birth weight.

Effects of stresses associated with extremely preterm birth may be biologically "recorded" in the genomes of individuals born preterm via changes in DNA methylation (DNAm) patterns. Genome-wide DNAm profiles were examined in buccal epithelial cells from 45 adults born at extremely low birth weight (ELBW; ≤1000 g) in the oldest known cohort of prospectively followed ELBW survivors (Mage = 32.35 years, 17 male), and 47 normal birth weight (NBW; ≥2500 g) control adults (Mage = 32.43 years, 20 male). Sex differences in DNAm profiles were found in both birth weight groups, but they were greatly enhanced in the ELBW group (77,895 loci) versus the NBW group (3,424 loci), suggesting synergistic effects of extreme prenatal adversity and sex on adult DNAm profiles. In men, DNAm profiles differed by birth weight group at 1,354 loci on 694 unique genes. Only two loci on two genes distinguished between ELBW and NBW women. Gene ontology (GO) and network analyses indicated that loci differentiating between ELBW and NBW men were abundant in genes within biological pathways related to neuronal development, synaptic transportation, metabolic regulation, and cellular regulation. Findings suggest increased sensitivity of males to long-term epigenetic effects of extremely preterm birth. Group differences are discussed in relation to particular gene functions.

Integrative Analysis of Glucometabolic Traits, Adipose Tissue DNA Methylation, and Gene Expression Identifies Epigenetic Regulatory Mechanisms of Insulin Resistance and Obesity in African Americans.

Decline in insulin sensitivity due to dysfunction of adipose tissue (AT) is one of the earliest pathogenic events in type 2 diabetes. We hypothesize that differential DNA methylation (DNAm) controls insulin sensitivity and obesity by modulating transcript expression in AT. Integrating AT DNAm profiles with transcript profile data measured in a cohort of 230 African Americans (AAs) from the African American Genetics of Metabolism and Expression cohort, we performed cis-expression quantitative trait methylation (cis-eQTM) analysis to identify epigenetic regulatory loci for glucometabolic trait-associated transcripts. We identified significantly associated cytosine-guanine dinucleotide regions for 82 transcripts (false discovery rate [FDR]-P < 0.05). The strongest eQTM locus was observed for the proopiomelanocortin (POMC; ρ = -0.632, P = 4.70 × 10-27) gene. Epigenome-wide association studies (EWAS) further identified 155, 46, and 168 cytosine-guanine dinucleotide regions associated (FDR-P < 0.05) with the Matsuda index, SI, and BMI, respectively. Intersection of EWAS, transcript level to trait association, and eQTM results, followed by causal inference test identified significant eQTM loci for 23 genes that were also associated with Matsuda index, SI, and/or BMI in EWAS. These associated genes include FERMT3, ITGAM, ITGAX, and POMC In summary, applying an integrative multiomics approach, our study provides evidence for DNAm-mediated regulation of gene expression at both previously identified and novel loci for many key AT transcripts influencing insulin resistance and obesity.

Differential DNA methylation profiles of peripheral blood mononuclear cells in allergic asthmatic children following dust mite immunotherapy

Allergen-specific immunotherapy (SIT) is now considered curative to allergic diseases such as asthma. Mechanistically, our previous work showed DNA hypermethylation of cytokine genes, in T-helper cells, in allergic asthmatic children treated with allergen-SIT. In this study, we extended to work to assess possible changes in the DNA methylomes of peripheral blood mononuclear cells (PBMCs), isolated from mite allergen-SIT asthmatic children, to explore further the underlying methylation changes. Thirteen allergic asthmatic children who received Der p-SIT, 12 non-SIT allergic asthmatic controls, and 12 healthy controls were enrolled. Bisulfite-converted DNA from Der p-stimulated PBMCs was analyzed using Human Methylation 450k BeadChip. Pyrosequencing and quantitative real-time PCR were used to validate the DNA methylation levels and the gene expression of individual samples. We identified 108 significantly differentially methylated regions (DMRs) unique to Der p-treated PBMCs, with 53 probes linked to demethylated DMRs, and 55 probes linked to methylated DMRs. Three associated genes (BCL6, HSPG2, and HSP90AA1), of selected DMRs, were subjected to bisulfite pyrosequencing. Of these, BCL6 showed significant hypomethylation, while HSPG2 and HSP90AA1 were hypermethylated in SIT group, compared to the AA group. Furthermore, SIT group had significantly higher gene expression of BCL6 and lower gene expression of HSPG2. KEGG pathway analysis further revealed DMR genes involved in ECM-receptor interactions, asthma, and antigen processing and presentation pathways. Several DNA regions showed DNA methylation altered by Der p specific immunotherapy, indicating desensitization-associated methylomes. Genes belonging to these SIT-altered pathways may represent therapeutic targets for better clinical management of asthma.

243-OR: Integrative Multiomics Analysis of Glucometabolic Traits, Adipose Tissue DNA Methylation, and Gene Expression Identifies Epigenetic Regulatory Mechanisms of Insulin Resistance and Obesity in African Americans

Decline in insulin sensitivity due to dysfunction of adipose tissue (AT) is one of the earliest pathogenic events in type 2 diabetes. We hypothesize that differential DNA methylation (DNAm) in regulatory regions of a subset of genes controls insulin sensitivity and obesity by modulating transcript expression in AT. Integrating reduced representation bisulfite sequencing-derived AT DNAm profiles for 1,054,719 CpG sites and 200,800 CpG regions with AT transcript profile data in 230 African Americans, we performed cis-expression quantitative trait methylation (cis-eQTM) analysis focused on 6,774 glucometabolic trait-associated transcripts to identify local epigenetic regulatory loci for these transcripts. We identified significantly associated CpG regions for 140 transcripts (FDR-P&amp;lt;0.1). The strongest eQTM locus was observed for the proopiomelanocortin (POMC; ρ= -0.632, P = 4.70X10-27) gene at the chr2:25,384,001-25,385,000 region covering a CpG island in the gene. Epigenome-wide association studies (EWAS) further examined the association of DNAm levels of CpG sites/regions with insulin sensitivity (Matsuda index and SI) and BMI. EWAS identified 520, 154, and 482 CpG regions associated (FDR-P &amp;lt;0.1) with Matsuda index, SI and BMI, respectively. We jointly analyzed the EWAS, transcript level to trait association, and eQTM data and identified significant eQTM loci for 26, 15 and 25 genes that were also associated with Matsuda index, SI and BMI, respectively in EWAS. These associated genes include fructose-2,6-biphosphatase 3 (PFKFB3), integrin alpha M (ITGAM), integrin alpha X (ITGAX), and POMC. In summary, applying an integrative multi-omics approach, our study provides evidence for DNAm-mediated regulation of gene expression at both previously identified and novel loci for many key AT transcripts influencing insulin resistance and obesity. Disclosure N.K. Sharma: None. M. Comeau: None. D.J. Montoya: None. M. Pellegrini: None. T. Howard: None. C.D. Langefeld: None. S.K. Das: None. Funding American Diabetes Association (1-18-ICTS-113 to S.K.D.); National Institutes of Health (R01DK090111)

Enrichment of genomic pathways based on differential DNA methylation profiles associated with chronic musculoskeletal pain in older adults: An exploratory study.

Our study aimed to identify differentially methylated CpGs/regions and their enriched genomic pathways associated with underlying chronic musculoskeletal pain in older individuals. We recruited cognitively healthy older adults with (n = 20) and without (n = 9) self-reported musculoskeletal pain and collected DNA from peripheral blood that was analyzed using MethylationEPIC arrays. We identified 31,739 hypermethylated CpG and 10,811 hypomethylated CpG probes (ps ≤ 0.05). All CpG probes were clustered into 5966 regions, among which 600 regions were differentially methylated at p ≤ 0.05 level, including 294 hypermethylated regions and 306 hypomethylated regions (differentially methylated regions). Ingenuity pathway enrichment analysis revealed that the pain-related differentially methylated regions were enriched across multiple pathways. The top 10 canonical pathways were linked to cellular signaling processes related to immune responses (i.e. antigen presentation, programed cell death 1 receptor/PD-1 ligand 1, interleukin-4, OX40 signaling, T cell exhaustion, and apoptosis) and gamma-aminobutyric acid receptor signaling. Further, Weighted Gene Correlation Network Analysis revealed a comethylation network module in the pain group that was not preserved in the control group, where the hub gene was the cyclic adenosine monophosphate-dependent transcription factor ATF-2. Our preliminary findings provide new epigenetic insights into the role of aberrant immune signaling in musculoskeletal pain in older adults while further supporting involvement of dysfunctional GABAergic signaling mechanisms in chronic pain. Our findings need to be urgently replicated in larger cohorts as they may serve as a basis for developing and targeting future interventions.

Genome-wide analysis of DNA methylation profile identifies differentially methylated loci associated with human intervertebral disc degeneration.

BackgroundEnvironmental and endogenous factors under genetic predisposition are considered to initiate the human intervertebral disc (IVD) degeneration. DNA methylation is an essential mechanism to ensure cell-specific gene expression for normal development and tissue stability. Aberrant epigenetic alterations play a pivotal role in several diseases, including osteoarthritis. However, epigenetic alternations, including DNA methylation, in IVD degeneration have not been evaluated. The purpose of this study was to comprehensively compare the genome-wide DNA methylation profiles of human IVD tissues, specifically nucleus pulpous (NP) tissues, with early and advanced stages of disc degeneration.MethodsHuman NP tissues were used in this study. The samples were divided into two groups: early stage degeneration (n = 8, Pfirrmann’s MRI grade: I-III) and advanced stage degeneration (n = 8, grade: IV). Genomic DNA was processed for genome-wide DNA methylation profiling using the Infinium MethylationEPIC BeadChip array. Extraction of raw methylation data, clustering and scatter plot of each group values of each sample were performed using a methylation module in GenomeStudio software. The identification of differentially methylated loci (DMLs) and the Gene Ontology (GO) analysis were performed using R software with the ChAMP package.ResultsUnsupervised hierarchical clustering revealed that early and advanced stage degenerated IVD samples segregated into two main clusters by their DNA methylome. A total of 220 DMLs were identified between early and advanced disc degeneration stages. Among these, four loci were hypomethylated and 216 loci were hypermethylated in the advanced disc degeneration stage. The GO enrichment analysis of genes containing DMLs identified two significant GO terms for biological processes, hemophilic cell adhesion and cell-cell adhesion.ConclusionsWe conducted a genome-wide DNA methylation profile comparative study and observed significant differences in DNA methylation profiles between early and advanced stages of human IVD degeneration. These results implicate DNA methylation in the process of human IVD degeneration.