Significant Differential Methylation Research Articles

The relationship of the methylation status and polymorphism of glucocorticoid receptor gene (NR3C1) with attempted suicide or non-suicidal self-injury patients in schizophrenia.

We aim to investigate the methylation of NR3C1 gene promotor and NR3C1 BclI polymorphism in schizophrenia (SCZ) patients with attempted suicide or non-suicidal self-injury (NSSI). A sample of 112 patients with SCZ was included in the study. Structured Clinical Interview for Diagnostic and Statistical Manual-Fourth Edition Axis I Disorders was used to confirm the diagnosis according to The Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision criteria. The patients were evaluated by data forms that had sociodemographic, suicidal behavior, and NSSI information. Methylation-specific polymerase chain reaction (PCR) was used to identify the methylation of the NR3C1 gene. The analysis of the BclI polymorphism of the NR3C1 gene was evaluated by using the PCR restriction fragment length polymorphism. Our results revealed that although the NR3C1 gene methylation was not statistically significantly different, there was a significant difference in NR3C1 genotype distribution among the SCZ groups with and without attempted suicide. SCZ patients carrying the CC genotype had a lower risk of attempted suicide (Odds Ratio [OR]: 0.421; 95% Confidence Interval [CI]: 0.183-0.970; p = 0.040), while having the GG genotype in SCZ patients was associated with a higher risk of attempted suicide (OR: 3.785; 95% Cl: 1.107-12.945; p = 0.042). Additionally, due to NSSI in SCZ patients, there were no significant differences in NR3C1 gene methylation and NR3C1 genotype distribution among the groups. We propose that the NR3C1 BclI polymorphism may be associated with attempted suicide in Turkish patients diagnosed with SCZ.

Integrative methylome and transcriptome analysis reveals epigenetic regulation of Fusobacterium nucleatum in laryngeal cancer.

The aetiological mechanisms of Fusobacterium nucleatum in laryngeal cancer remain unclear. This study aimed to reveal the epigenetic signature induced by F. nucleatum in laryngeal squamous cell carcinoma (LSCC). Combined analysis of methylome and transcriptome data was performed to address the functional role of F. nucleatum in laryngeal cancer. Twenty-nine differentially expressed methylation-driven genes were identified by mapping the methylation levels of significant differential methylation sites to the expression levels of related genes. The combined analysis revealed that F. nucleatum promoted Janus kinase 3 (JAK3) gene expression in LSCC. Further validation found decreased methylation and elevated expression of JAK3 in the F. nucleatum-treated LSCC cell group; F. nucleatum abundance and JAK3 gene expression had a positive correlation in tumour tissues. This analysis provides a novel understanding of the impact of F. nucleatum in the methylome and transcriptome of laryngeal cancer. Identification of these epigenetic regulatory mechanisms opens up new avenues for mechanistic studies to explore novel therapeutic strategies.

Abstract 6225: Tumor evolution through selection by ECM stiffness

Abstract In this study, we used experimental evolution to investigate the extent to which the mechanical stiffness of the tumor extracellular matrix (ECM) exerts selection pressure on a genetically diverse population of breast cancer cells. Polyacrylamide hydrogels were fabricated and conjugated with collagen type I to create the ECM with different stiffness. MDA-MB-231 cells were continuously cultured on the hydrogels of the same corresponding stiffness. Growth rate was determined at certain time points by harvesting and counting the cells. Abundance of clonal MDA-MB-231 cells labeled with heritable DNA barcodes underwent the same selection was identified with sequencing of DNA barcode tags. Cellular phenotypes were characterized through immunofluorescence staining and confocal microscopy. 3D migration of the cancer cells was examined using Boyden chamber assay. Cellular contractility was measured through traction force microscopy. Whole genome transcriptome sequencing (RNA-seq), assay for transposase-accessible chromatin with sequencing, and reduced representation bisulfite sequencing were performed for transcriptomic and epigenetic analysis. Sustained culture of MDA-MB-231 breast cancer cells overall three months on soft ECM resulted in an increased proliferation rate and beta1 integrin-dependent spreading area of the cells. Such changes did not occur in clonal cells with low genetic variation and did not occur in ancestral cells on stiff substrates. Barcode analysis revealed two distinct surviving populations post-genetic selection, with one demonstrating robust proliferation on both soft and stiff ECM, and the other exhibiting preferential adaptation to the soft matrix. The soft-selected populations exhibited nuclear localization of the transcriptional regulator yes-associated protein and less wrinkled nuclei compared with ancestral populations when both populations were grown on soft ECM. Aggressive migration was observed in the soft-selected populations, indicating a more malignant selected phenotype. The soft-selected cells showed increased RhoA activity and contractile tension on a soft substrate compared to the ancestral cells. RNA-seq analysis revealed systematic differences between ancestral, stiff-selected, and soft-selected populations corresponding to enriched biological processes related to cell adhesion and ECM organization. Significant differences in DNA methylation and chromatin accessibility were observed in soft selected populations which were correlated with changes in RNA expression. ECM stiffness exerts selection pressure on genetically variable cancer cell populations, selecting specific genetic variants in a cell population optimally adapted for that stiffness. Selected variants on soft ECM tend to be highly migratory, proliferative and generate high traction even on soft ECM. Our results highlight the importance of ECM stiffness-driven evolution in cancer development. Citation Format: Ting-Ching Wang, Suchitaa Sawhney, Daylin Morgan, Richa Rashmi, Marcos R. Estecio, Amy Brock, Irtisha Singh, Richard L. Bennett, Charles F. Baer, Jonathan D. Licht, Tanmay P. Lele. Tumor evolution through selection by ECM stiffness [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6225.

DNA methylation of ELOVL2 gene as an epigenetic marker of age among Egyptian population

BackgroundCellular and molecular changes occur during aging, decreasing organ function. The aging process was measured by several biomarkers, including DNA methylation (DNAm), an epigenetic change regulating gene expression, which is highly accurate at predicting biological age. DNAm is heritable and therefore varies between different populations.AimTo assess blood DNA methylation changes as epigenetic clocks in the male and female Egyptian population. Pyrosequencing was used to measure the methylation of nine CpG sites in blood samples from 100 healthy Egyptians (18–69 years) using a cross-sectional study. Two age predicted models based on the ELOVL2 gene were compared in three age categories and correlated in all age groups despite decreasing accuracy with increasing age.ResultsThe mean absolute deviation (MAD) using the 1st and 2nd age predicted models for 18–40 years was 1.06 and 2.7, respectively; for 41–60 years, it was 4.4 and 3.8, respectively; and for > 60 years, it was 7.7 and 7.0, respectively. No significant differences in DNA methylation were found between the sexes.ConclusionDNA methylation of the ELOVL2 gene can be used as an accurate biomarker for age estimation. Additionally, this method has the potential to be more accurate than traditional methods of age estimation.

Association of GAL-8 promoter methylation levels with coronary plaque inflammation

Background and aimsCoronary heart disease (CHD) is a condition that carries a high risk of mortality and is associated with aging. CHD is characterized by the chronic inflammatory response of the coronary intima. Recent studies have shown that the methylation level of blood mononuclear cell DNA is closely associated with adverse events in CHD, but the roles and mechanisms of DNA methylation in CHD remain elusive. Methods and resultsIn this study, the DNA methylation status within the epigenome of human coronary tissue in the sudden coronary death (SCD) group and control (CON) group of coronary heart disease was analyzed using the Illumina® Infinium Methylation EPIC BeadChip (850 K chip), resulting in the identification of a total of 2553 differentially methylated genes (DMGs). The differentially methylated genes were then subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and significant differential DNA methylation was found. Among the differentially hypomethylated genes were GAL-8, LTF, and RFPL3, while the highly methylated genes were TMEM9B, ANK3, and C6orF48. These genes were mainly enriched in 10 significantly enriched pathways, such as cell adhesion junctions, among which the differentially methylated gene GAL-8 was involved in inflammatory pathway signaling. For functional analysis of GAL-8, we first examined the differences in GAL-8 promoter methylation levels among different subgroups of human coronary tissue in the CON, CHD, and SCD groups using pyrophosphate sequencing. The results revealed reduced GAL-8 promoter methylation levels in the SCD group, while the difference between the CHD and CON groups was not statistically significant (P > 0.05). The reduced GAL-8 promoter methylation level was associated with upregulated GAL-8 expression, which led to increased expression of the inflammatory markers TNF-α, IL-1β, MCP-1, MIP-2, MMP-2, and MMP-9. This enhanced inflammatory response contributed to the accumulation of foam cells, thickening of the intima of human coronary arteries, and increased luminal stenosis, which promoted the occurrence of sudden coronary death. Next, we found that GAL-8 promoter methylation levels in PBMC were consistent with human coronary tissue. The unstable angina group (UAP) had significantly lower GAL-8 promoter methylation levels than stable angina (SAP) and healthy controls (CON) (P < 0.05), and there was a significant correlation between reduced GAL-8 promoter methylation levels and risk factors for coronary heart disease. These findings highlight the association between decreased GAL-8 promoter methylation and the presence of coronary heart disease risk factors. ROC curve analysis suggests that methylation of the GAL 8 promoter region is an independent risk factor for CHD. In conclusion, our study confirmed differential expression of GAL-8, LTF, MUC4D, TMEM9B, MYOM2, and ANK3 genes due to DNA methylation in the SCD group. We also established the consistency of GAL-8 promoter methylation alterations between human coronary tissue and patient peripheral blood monocytes. The decreased methylation level of the GAL-8 promoter may be related to the increased expression of GAL-8 and the coronary risk factors. ConclusionsAccordingly, we hypothesized that reduced levels of GAL-8 promoter methylation may be an independent risk factor for adverse events in coronary heart disease.

The Effect of Maternal Diet and Physical Activity on the Epigenome of the Offspring.

The aim of this review was to examine the current literature regarding the effect of maternal lifestyle interventions (i.e., diet and physical activity) on the epigenome of the offspring. PubMed, Scopus and Cochrane-CENTRAL were screened until 8 July 2023. Only randomized controlled trials (RCTs) where a lifestyle intervention was compared to no intervention (standard care) were included. Outcome variables included DNA methylation, miRNA expression, and histone modifications. A qualitative approach was used for the consideration of the studies' results. Seven studies and 1765 mother-child pairs were assessed. The most common types of intervention were dietary advice, physical activity, and following a specific diet (olive oil). The included studies correlated the lifestyle and physical activity intervention in pregnancy to genome-wide or gene-specific differential methylation and miRNA expression in the cord blood or the placenta. An intervention of diet and physical activity in pregnancy was found to be associated with slight changes in the epigenome (DNA methylation and miRNA expression) in fetal tissues. The regions involved were related to adiposity, metabolic processes, type 2 diabetes, birth weight, or growth. However, not all studies showed significant differences in DNA methylation. Further studies with similar parameters are needed to have robust and comparable results and determine the biological role of such modifications.

Alterations in leukocyte DNA methylome are associated to immunosuppression in severe clinical phenotypes of septic patients.

Sepsis patients experience a complex interplay of host pro- and anti-inflammatory processes which compromise the clinical outcome. Despite considering the latest clinical and scientific research, our comprehension of the immunosuppressive events in septic episodes remains incomplete. Additionally, a lack of data exists regarding the role of epigenetics in modulating immunosuppression, subsequently impacting patient survival. To advance the current understanding of the mechanisms underlying immunosuppression, in this study we explored the dynamics of DNA methylation using the Infinium Methylation EPIC v1.0 BeadChip Kit in leukocytes from patients suffering from sepsis, septic shock, and critically ill patients as controls, within the first 24 h after admission in the Intensive Care Unit of a tertiary hospital. Employing two distinct analysis approaches (DMRcate and mCSEA) in comparing septic shock and critically ill patients, we identified 1,256 differentially methylated regions (DMRs) intricately linked to critical immune system pathways. The examination of the top 100 differentially methylated positions (DMPs) between septic shock and critically ill patients facilitated a clear demarcation among the three patient groups. Notably, the top 6,657 DMPs exhibited associations with organ dysfunction and lactate levels. Among the individual genes displaying significant differential methylation, IL10, TREM1, IL1B, and TNFAIP8 emerged with the most pronounced methylation alterations across the diverse patient groups when subjected to DNA bisulfite pyrosequencing analysis. These findings underscore the dynamic nature of DNA methylation profiles, highlighting the most pronounced alterations in patients with septic shock, and revealing their close association with the disease.

Expression and promoter methylation of mitogen-activated protein kinase 1 in tumor and marginal cells of breast cancer.

In the present study, we sought to explore potential differences in the expression and promoter methylation of mitogen-activated protein kinase 1 (MAPK1) between tumor and marginal cells of breast cancer lesions. A total of 50 randomly selected patients with breast cancer (BCa) undergoing needle biopsy were enrolled. Clinical specimens containing both tumor and marginal cells were collected and preserved. After DNA extraction using specific primers, MAPK1 mRNA and promoter methylation were measured with spectrophotometry at 260/280 nm absorption wavelengths. To deliver a comparative analysis, data from The Cancer Genome Atlas (TCGA) program regarding breast cancer (BRCA), were downloaded from Xena Functional Genomics Explorer and separately analyzed. The suitability of MAPK1 expression and promoter methylation as biomarkers for BCa was analyzed with receiver operating characteristic (ROC) curves. We found a positive correlation between tumor stage and MAPK1 expression (P-value: 0.029) in BCa. Likewise, MAPK1 expression was significantly associated with lymph node metastasis (P-value: 0.018). There was a significant difference in the expression of MAPK1 mRNA between tumor and marginal cells of BCa and BRCA (P-value < 0.001). However, we did not find any statistically significant difference in MAPK1 promoter methylation between tumor and marginal cells of both BCa and BRCA. With an area under the curve (AUC) of 0.71, the diagnostic accuracy of MAPK1 expression in BCa and BRCA was validated. However, MAPK1 promoter methylation was not found to be a suitable biomarker. Our findings suggest that while MAPK1 expression, might be a promising biomarker for evaluating oncogenic activity in patients suspected of BCa. We were not able to detect a prognostic/diagnostic role for MAPK1 promoter methylation.

Value of altered methylation patterns of genes RANBP3, LCP2 and GRAP2 in cfDNA in breast cancer diagnosis

Background: The purpose of this study was to investigate the potential of plasma cfDNA methylation patterns in reflecting tumor methylation changes, focusing on three candidate sites, cg02469161, cg11528914, and cg20131654. These sites were selected for verification, with a particular emphasis on their association with breast cancer.&#x0D; Methods: We conducted a comprehensive analysis of 850k whole-methylation sequencing data to identify potential markers for breast cancer detection. Subsequently, we examined the methylation status of genes RANBP3, LCP2, and GRAP2, where the aforementioned sites are located, using cancer and cancer-adjacent tissues from 17 breast cancer patients. We also assessed the methylation patterns in different molecular subtypes and pathological grades of breast cancer. Additionally, we compared the methylation levels of these genes in plasma cfDNA to their performance in tissues.&#x0D; Results: Our analysis revealed that RANBP3, LCP2, and GRAP2 genes exhibited significant methylation differences between cancer and cancer-adjacent tissues. In breast cancer, these genes displayed diagnostic efficiencies of 91.0%, 90.6%, and 92.2%, respectively. Notably, RANBP3 showed a tendency towards lower methylation in HR+ breast cancer, and LCP2 methylation was correlated with tumor malignancy. Importantly, the methylation levels of these three genes in plasma cfDNA closely mirrored their tissue counterparts, with diagnostic efficiencies of 83.3%, 83.9%, and 77.6% for RANBP3, LCP2, and GRAP2, respectively.&#x0D; Conclusions: Our findings suggest that RANBP3, LCP2, and GRAP2 genes, located at the identified methylation sites, can serve as valuable blood molecular markers for the auxiliary diagnosis of breast cancer. This research provides a foundation for further exploration of gene methylation pattern changes in cfDNA for the detection of breast cancer and other cancer types.

10184-BT-14 CLINICAL FEATURE OF HEMISPHERIC GLIOMA WITH H3F3A, PEDIATRIC-TYPE HIGH GRADE GLIOMA, H3 K27-ALTERED, NEC AND DIFFUSE HEMISPHERIC GLIOMA, H3 G34-MUTANT, CNS WHO GRADE 4

Abstract INTRODUCTION Diffuse midline glioma (DMG), H3K27-altered, is a CNS WHO grade 4 glioma that usually located mainly in the brainstem, thalamus and spinal cord. However, DMG located in non-midline lesions are now described as pediatric-type high grade glioma, H3K27-altered, NEC (NDMG). On the other hand, diffuse hemispheric glioma, H3G34-mutant (DHG) located in the cerebral hemispheres, and is classified under the WHO 2021 classification. It is unknown that the differences in clinical characteristics of these hemispheric tumors with H3F3A mutations. In the present study, we report a comparative study of the clinical characteristics of two groups of NDMG and DHG. METHODS Among 4128 brain tumor samples collected in the Kansai Network for Molecular Diagnosis of Central Nervous System Tumors, 16 NDMG and 9 DHG cases were examined for comparison of clinical characteristics. RESULTS There were no differences in gender, tumor location, or pathology between NDMG and DHG. The median age was 47.3 years in NDMG and 26.2 years in DHG, and NDMG was significantly older than DHG (p=0.003). There was no significant difference in MGMT promoter methylation between NDMG and DHG (p=0.087). The Kaplan-Meier survival curve showed no significant difference, with a median survival of 495 days for NDMG and 587 days for DHG (p=0.765). There was no significant different survival rate between WHO grade 3 (n=15) and grade 4 (n=9) for pathological diagnosis. DISCUSSION AND CONCLUSION We compared the clinical characteristics of NDMG and DHG. There are some reports that NDMG and DHG gliomas located in non-midline lesion. Removing much tumor volume may improve the prognosis of non-midline glioma. We discuss the gliomas with H3F3A mutations located in a hemispheric lesions by literature review.

A multi‐omic approach to elucidate novel disease mechanisms and biomarkers for psychosis in Alzheimer’s disease

AbstractBackgroundPsychosis is a debilitating syndrome occurring in 40‐60% of people with Alzheimer’s disease (AD) and corresponds with a more severe disease course. Evidence suggests that psychosis in AD is associated with a distinct profile of microbiological changes, but little is known about the molecular processes driving etiology.MethodGenome‐wide DNA methylation, small non‐coding (nc) RNAs (microRNA, transfer RNA, piwiRNA) and long coding and ncRNAs (mRNA, lincRNA, cicular RNAs) were quantified from 248 whole blood samples obtained from the Norwegian registry of persons assessed for cognitive symptoms (NorCog) cohort. Multi‐omics profiles of AD patients with psychosis (AD+P) were compared to the patients without psychosis (AD‐P).ResultThere were significant differences in DNA methylation, small ncRNAs, and long coding and ncRNAs between AD+P and AD‐P patients. Further analysis revealed specific genomic regions and molecular pathways that were differentially methylated or expressed in AD+P patients compared to AD‐P patients.ConclusionOur findings suggest that there may be distinct molecular signatures associated with AD psychosis, and that these differences may potentially be used as biomarkers for the early detection and diagnosis of AD psychosis.

Integrated Analysis Focusing on Genome-Wide DNA Methylation in Pediatric Acute Promyelocytic Leukemia: The Jccg Study, JPLSG AML-P05

Introduction: Pediatric acute promyelocytic leukemia (APL) represents approximately 5%-10% of all acute myeloid leukemia (AML). While the prognosis of APL patients has dramatically improved with the use of all-trans retinoic acid and arsenic trioxide, cases of relapse still exist. Moreover, the molecular biological basis of pediatric APL remains unknown. In adult and pediatric AML, to predict prognosis, DNA methylation patterns have been proposed as biomarkers. In this study, we aimed to investigate the molecular biological basis of pediatric APL and validate biomarkers associated with prognosis using an integrated analysis, including DNA methylation analysis, targeted deep sequencing, and RNA sequencing, in patients enrolled in the Japanese AML-P05 study conducted by the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG). Methods: Pediatric de novo APL patients (n = 38) who participated in the JPLSG AML-P05 trial from 2006 to 2009 were analyzed. Genome-wide DNA methylation analysis (n = 34), targeted deep sequencing (n = 35), RNA sequencing (n = 34), and motif analysis (n = 34) were performed. In the DNA methylation analysis, the Infinium MethylationEPIC v2.0 Kit (Illumina) was used. Results: Based on the most variable 1,000 DNA methylation values between patients, unsupervised hierarchical clustering classified APL patients into four clusters (cluster 1, 2a, 2b, and 3). Clusters 1 and 2a (n = 15) demonstrated a significantly higher DNA methylation levels at 87 CpG sites out of 1,000 compared to clusters 2b and 3 (n = 19). A part of the 87 CpG sites locate on the genes, such as CPM, GRB10 and BAALC, which have been reported to be associated with APL prognosis. A significant DNA methylation difference was found between the “high” (cluster 1 and 2a) and “low” (cluster 2b and 3) methylation groups at 2,372 CpG sites (Figure). Patients in the high methylation group presented with significantly worse outcomes compared to those in the low methylation group (3-year overall survival: 80% vs. 100%, p = 0.043; 3-year event-free survival: 73.3% vs. 94.7%, p = 0.049). Additionally, among the 2,372 CpG sites, motif analysis was performed for 783 CpG sites with an average methylation difference of 0.3 or higher. The binding domain of EBF1 was enriched among them. EBF1 is a critical transcriptional factor for B-cell differentiation. In the high methylation group, an aberrant B-cell differentiation was considered as a characteristic of APL. Gene expression analysis between the high and low methylation groups revealed significant differences in expression of 600 genes with more than twofold changes. Gene ontology analysis of the 600 genes revealed that their genes were enriched in T-cell and B-cell linage differentiation. In the targeted deep sequencing analysis, a total of 41 mutations in 21 genes in 25 patients were identified. The most frequent mutation was NRAS. Interestingly, previously unreported mutations in EP300 and BRCA2 were identified in APL, with EP300 mutations detected only in the high methylation group. Conclusions: DNA methylation analysis suggests that DNA methylation levels at specific CpG sites are effective biomarkers for the prognosis of pediatric APL. The presence of the EBF1 binding motif in the vicinity of these CpG sites suggests the involvement of EBF1 in prognosis.

Comprehensive Analyses and Experiments Confirmed IGFBP5 as a Prognostic Predictor Based on an Aging-genomic Landscape Analysis of Ovarian Cancer.

Ovarian cancer (OC) is one of the malignant diseases of the reproductive system in elderly women. Aging-related genes (ARGs) were involved in tumor malignancy and cellular senescence, but the specifics of these mechanisms in OC remain unknown. ARGs expression and survival data of OC patients were collected from TCGA and CPTAC databases. Subtype classification was used to identify the roles of hub ARGs in OC progression, including function enrichment, immune infiltration, and drug sensitivity. LASSO regression was utilized to confirm the prognosis significance for these hub ARGs. MTT, EdU, Transwell, and wounding healing analysis confirmed the effect of IGFBP5 on the proliferation and migration ability of OC cells. ARGs were ectopically expressed in OC tissues compared to normal ovary tissues. Three molecular subtypes were divided by ARGs for OC patients. There were significant differences in ferroptosis, m6A methylation, prognosis, immune infiltration, angiogenesis, differentiation level, and drug sensitivity among the three groups. LASSO regression indicated that 4 signatures, FOXO4, IGFBP5, OGG1 and TYMS, had important prognosis significance. Moreover, IGFBP5 was significantly correlated with immune infiltration. The hub ARG, IGFBP5, expression was significantly decreased in OC patients compared to normal women. IGFBP5 could also reduce the migration and proliferation ability of OC cells compared to vector and NC groups. IGFBP5 was correlated with OC prognosis and associated with OC migration and proliferation. This gene may serve as potential prognostic biomarkers and therapeutic targets for OC patients.

DNA Methylation Profiling of Ovarian Tissue of Climbing Perch (Anabas testudienus) in Response to Monocrotophos Exposure.

Epigenetic modifications like DNA methylation can alter an organism's phenotype without changing its DNA sequence. Exposure to environmental toxicants has the potential to change the resilience of aquatic species. However, little information is available on the dynamics of DNA methylation in fish gonadal tissues in response to organophosphates. In the present work, reduced-representation bisulfite sequencing was performed to identify DNA methylation patterns in the ovarian tissues of Anabas testudienus exposed to organophosphates, specifically monocrotophos (MCP). Through sequencing, an average of 41,087 methylated cytosine sites were identified and distributed in different parts of genes, i.e., in transcription start sites (TSS), promoters, exons, etc. A total of 1058 and 1329 differentially methylated regions (DMRs) were detected as hyper-methylated and hypo-methylated in ovarian tissues, respectively. Utilizing whole-genome data of the climbing perch, the DMRs, and their associated overlapping genes revealed a total of 22 genes within exons, 45 genes at transcription start sites (TSS), and 218 genes in intergenic regions. Through gene ontology analysis, a total of 16 GO terms particularly involved in ovarian follicular development, response to oxidative stress, oocyte maturation, and multicellular organismal response to stress associated with reproductive biology were identified. After functional enrichment analysis, relevant DMGs such as steroid hormone biosynthesis (Cyp19a, 11-beta-HSD, 17-beta-HSD), hormone receptors (ar, esrrga), steroid metabolism (StAR), progesterone-mediated oocyte maturation (igf1ar, pgr), associated with ovarian development in climbing perch showed significant differential methylation patterns. The differentially methylated genes (DMGs) were subjected to analysis using real-time PCR, which demonstrated altered gene expression levels. This study revealed a molecular-level alteration in genes associated with ovarian development in response to chemical exposure. This work provides evidence for understanding the relationship between DNA methylation and gene regulation in response to chemicals that affect the reproductive fitness of aquatic animals.

Correlation of the methylomic signature of smoking during pregnancy with clinical traits in ADHD.

Attention deficit/hyperactivity disorder (ADHD) is a highly prevalent childhood disorder. Maternal smoking during pregnancy is a replicated environmental risk factor for this disorder. It is also a robust modifier of gene methylation during the prenatal developmental period. In this study, we sought to identify loci differentially methylated by maternal smoking during pregnancy and relate their methylation levels to various behavioural and physical outcomes relevant to ADHD. We extracted DNA from blood samples from children diagnosed with ADHD and deeply phenotyped. Genome-wide DNA methylation was assessed using Infinium MethylationEPIC BeadChip. Maternal smoking during pregnancy was self-declared and assessed retrospectively. Our sample included 231 children with ADHD. Statistically significant differences in DNA methylation between children exposed or not to maternal smoking during pregnancy were detected in 3457 CpGs. We kept 30 CpGs with at least 5% of methylation difference between the 2 groups for further analysis. Six genes were associated with varied phenotypes of clinical relevance to ADHD. The levels of DNA methylation in RUNX1 were positively correlated with the CBCL scores, and DNA methylation in MYO1G correlated positively with the score at the Conners rating scale. Methylation level in a CpG located in GFI1 correlated with birthweight, a risk factor for ADHD. Differentially methylated regions were also identified and confirmed the association of RUNX1 methylation levels with the CBCL score. The study has several limitations, including the retrospective recall with self-report of maternal smoking during pregnancy as well as the grouping of individuals of varying age and developmental stage and of both males and females. In addition, the correlation design prevents the building of causation models. This study provides evidence for the association between the level of methylation at specific loci and quantitative dimensions highly relevant for ADHD as well as birth weight, a measure that has already been associated with increased risk for ADHD. Our results provide further support to public health educational initiatives to stop maternal smoking during pregnancy.

Comprehensive Transcriptomic Profiling of m6A Modification in Age-Related Hearing Loss.

Age-related hearing loss (ARHL), also known as presbycusis, is one of the most common neurodegenerative disorders in elderly individuals and has a prevalence of approximately 70-80% among individuals aged 65 and older. As ARHL is an intricate and multifactorial disease, the exact pathogenesis of ARHL is not fully understood. There is evidence that transcriptional dysregulation mediated by epigenetic modifications is widespread in ARHL. However, the potential role of N6-methyladenosine (m6A) modification, as a crucial component of epigenetics, in ARHL progression remains unclear. In this study, we confirmed that the downregulation of m6A modification in cochlear tissues is related to ARHL and found that the expression of the m6A methylation regulators Wilms tumour suppressor-1-associated protein (WTAP), methyltransferase-like 3 (METTL3), ALKB homologous protein 5 (ALKBH5) and fat mass and obesity-associated protein (FTO) is decreased significantly at the mRNA and protein levels in ARHL mice. Then, we used methylated RNA immunoprecipitation sequencing (MeRIP-Seq) and RNA sequencing (RNA-Seq) to identify the differentially m6A-methylated genes in the cochlear tissues of ARHL mice. A total of 3438 genes with differential m6A methylation were identified, of which 1332 genes were m6A-hypermethylated and 2106 genes were m6A-hypomethylated in the ARHL group compared to the control group according to MeRIP-seq. Further joint analysis of RNA-Seq and MeRIP-Seq data showed that 262 genes had significant differences in both mRNA expression and m6A methylation. GO and KEGG analyses indicated that 262 unique genes were enriched mainly in the PI3K-AKT signalling pathway. In conclusion, the results of this study reveal differential m6A methylation patterns in the cochlear tissues of ARHL mice, providing a theoretical basis for further study of the pathogenesis of ARHL and potential therapeutic strategies.

Indoor particulate matter induces epigenetic changes in companion atopic dogs

The prevalence of atopic dermatitis (AD) is increasing and environmental factors are receiving attention as contributing causes. Indoor air pollutants (IAPs), especially particulate matter (PM) can alter epigenetic markers, DNA methylation (DNAm). Although DNAm-mediated epigenetic changes have been reported to modulate the pathogenesis of AD, their role at high risk of exposure to PM is still unclear. The study investigated the effects of exposure to IAPs in the development of AD and epigenetic changes through DNAm in companion atopic dogs that share indoor environment with their owners. Dogs were divided into two groups: AD (n = 47) and controls (n = 21). The IAPs concentration in each household was measured for 48 h, and a questionnaire on the residential environment was completed in all dogs. Eighteen dogs with AD and 12 healthy dogs were selected for DNAm analysis. In addition, clinical and immunological evaluations were conducted. The concentrations of PM2.5, PM10, and volatile organic compounds (VOCs) were significantly higher in the AD group. Moreover, there were more significant methylation differences in the LDLRAD4, KHSRP, and CTDSP2 genes in connection with PM10 in AD group compared to the controls. The degree of methylation of the LDLRAD4 and CTDSP2 genes was also correlated with related protein productions. The present study revealed that exposure to high indoor PM can cause epigenetic development of AD by methylation of the LDLRAD4, KHSRP, and CTDSP2 genes in dogs. Under the concept of "One Health," improving indoor environments should be considered to prevent the development of AD.

DNA methylation differences within INS, PTPN22 and IL2RA promoters in lymphocyte subsets in children with type 1 diabetes and controls

We elucidated the effect of four known T1D-susceptibility associated single nucleotide polymorphism (SNP) markers in three genes (rs12722495 and rs2104286 in IL2RA, rs689 in INS and rs2476601 in PTPN22) on CpG site methylation of their proximal promoters in different lymphocyte subsets using pyrosequencing. The study cohort comprised 25 children with newly diagnosed T1D and 25 matched healthy controls. The rs689 SNP was associated with methylation at four CpG sites in INS promoter: −234, −206, −102 and −69. At all four CpG sites, the susceptibility genotype AA was associated with a higher methylation level compared to the other genotypes. We also found an association between rs12722495 and methylation at CpG sites −373 and −356 in IL2RA promoter in B cells, where the risk genotype AA was associated with lower methylation level compared to the AG genotype. The other SNPs analyzed did not demonstrate significant associations with CpG site methylation in the examined genes. Additionally, we compared the methylation between children with T1D and controls, and found statistically significant methylation differences at CpG −135 in INS in CD8+ T cells (p = 0.034), where T1D patients had a slightly higher methylation compared to controls (87.3 ± 7.2 vs. 78.8 ± 8.9). At the other CpG sites analyzed, the methylation was similar. Our results not only confirm the association between INS methylation and rs689 discovered in earlier studies but also report this association in sorted immune cells. We also report an association between rs12722495 and IL2RA promoter methylation in B cells. These results suggest that at least part of the genetic effect of rs689 and rs12722495 on T1D pathogenesis may be conveyed by DNA methylation.

Genome-Wide DNA Methylation and Gene Expression in Patients with Indolent Systemic Mastocytosis.

Mastocytosis is a clinically heterogenous, usually acquired disease of the mast cells with a survival time that depends on the time of onset. It ranges from skin-limited to systemic disease, including indolent and more aggressive variants. The presence of the oncogenic KIT p. D816V gene somatic mutation is a crucial element in the pathogenesis. However, further epigenetic regulation may also affect the expression of genes that are relevant to the pathology. Epigenetic alterations are responsible for regulating the expression of genes that do not modify the DNA sequence. In general, it is accepted that DNA methylation inhibits the binding of transcription factors, thereby down-regulating gene expression. However, so far, little is known about the epigenetic factors leading to the clinical onset of mastocytosis. Therefore, it is essential to identify possible epigenetic predictors, indicators of disease progression, and their link to the clinical picture to establish appropriate management and a therapeutic strategy. The aim of this study was to analyze genome-wide methylation profiles to identify differentially methylated regions (DMRs) in patients with mastocytosis compared to healthy individuals, as well as the genes located in those regulatory regions. Genome-wide DNA methylation profiling was performed in peripheral blood collected from 80 adult patients with indolent systemic mastocytosis (ISM), the most prevalent subvariant of mastocytosis, and 40 healthy adult volunteers. A total of 117 DNA samples met the criteria for the bisulfide conversion step and microarray analysis. Genome-wide DNA methylation analysis was performed using a MethylationEPIC BeadChip kit. Further analysis was focused on the genomic regions rather than individual CpG sites. Co-methylated regions (CMRs) were assigned via the CoMeBack method. To identify DMRs between the groups, a linear regression model with age as the covariate on CMRs was performed using Limma. Using the available data for cases only, an association analysis was performed between methylation status and tryptase levels, as well as the context of allergy, and anaphylaxis. KEGG pathway mapping was used to identify genes differentially expressed in anaphylaxis. Based on the DNA methylation results, the expression of 18 genes was then analyzed via real-time PCR in 20 patients with mastocytosis and 20 healthy adults. A comparison of the genome-wide DNA methylation profile between the mastocytosis patients and healthy controls revealed significant differences in the methylation levels of 85 selected CMRs. Among those, the most intriguing CMRs are 31 genes located within the regulatory regions. In addition, among the 10 CMRs located in the promoter regions, 4 and 6 regions were found to be either hypo- or hypermethylated, respectively. Importantly, three oncogenes-FOXQ1, TWIST1, and ERG-were identified as differentially methylated in mastocytosis patients, for the first time. Functional annotation revealed the most important biological processes in which the differentially methylated genes were involved as transcription, multicellular development, and signal transduction. The biological process related to histone H2A monoubiquitination (GO:0035518) was found to be enriched in association with higher tryptase levels, which may be associated with more aberrant mast cells and, therefore, more atypical mast cell disease. The signal in the BAIAP2 gene was detected in the context of anaphylaxis, but no significant differential methylation was found in the context of allergy. Furthermore, increased expression of genes encoding integral membrane components (GRM2 and KRTCAP3) was found in mastocytosis patients. This study confirms that patients with mastocytosis differ significantly in terms of methylation levels in selected CMRs of genes involved in specific molecular processes. The results of gene expression profiling indicate the increased expression of genes belonging to the integral component of the membrane in mastocytosis patients (GRM2 and KRTCAP3). Further work is warranted, especially in relation to the disease subvariants, to identify links between the methylation status and the symptoms and novel therapeutic targets.

Hypomethylation of DRD2 promotes breast cancer through the FLNA-ERK pathway

We investigated the effect of stem cell marker dopamine receptor D2 (DRD2) on the proliferation of hormone-receptor-negative breast cancer cells. High-throughput DNA methylation sequencing on an 850 K chip was used to pre-screen breast cancer tissues with significant methylation differences. The expression of DRD2 in breast cancer and normal breast tissues, and clinical risk factors, were detected by pyrophosphoric acid validation and immunohistochemistry. In vitro and in vivo experiments verified the possible molecular signaling pathways. DRD2 promoter region was hypomethylated in hormone-receptor-negative breast cancer or with high-risk factors compared to the normal tissues. The proliferation of breast cancer cells was enhanced after DRD2 was upregulated and decreased after DRD2 was downregulated. In vivo experiments found that tumor growth and the expression of antigen KI-67 (Ki67) and the cluster of differentiation 31 (CD31) were improved by the overexpression of DRD2 and inhibited by the down expression of DRD2. In vivo and in vitro experiments demonstrated the phosphorylation of filamin A and extracellular signal-regulated kinase (FLNA-ERK) was influenced by the expression of DRD2, suggesting DRD2 plays a role in the FLNA-ERK signaling pathway. Methylation inhibitors (5-aza-2-deoxycytidine, 5-azadc) partially reversed the inhibitory effect of DRD2 down expression on cell proliferation, migration, and tumor growth in animal models, indicating that inhibition of DRD2 methylation promotes cancer development. This study demonstrated the DRD2 promoter region is hypomethylated in hormone-receptor-negative breast cancer or with high-risk factors. The methylation status of the DRD2 promoter and FLNA-ERK signaling pathway and the DRD2 expression in breast cancer treatment need to be considered.