Global DNA Methylation Status Research Articles

Traditional Korean diet high in one-carbon nutrients increases global DNA methylation: implication for epigenetic diet.

DNA methylation is a major epigenetic phenomenon through which diet affects health and disease. This study aimed to determine the epigenetic influence of the traditional Korean diet (K-diet) on global DNA methylation via one-carbon metabolism. A crossover study was conducted on 52 women. Two diets, a K-diet, high in plant foods and low in calories and animal fat, and a control diet, similar to the diet currently consumed in Korea, were provided to all subjects alternately for 4weeks with a 4-week washout period. Clinical parameters were measured before and after each dietary intervention. Nutrient intake was calculated by using a computer-aided nutritional analysis program. One-carbon metabolites in the serum and global DNA methylation in peripheral mononuclear cells were determined using ultra-performance liquid chromatography-tandem mass spectrometry. The K-diet group consumed more folate (669.9 ± 6.7µg vs. 502.7 ± 3.0, p < 0.001), B6, B12, serine, and choline, and less methionine (992.6 ± 63 vs. 1048.3mg ± 34.1, p < 0.0001) than the control group did. In the K-diet group, the increment of plasma 5-methyltetrahydrofolate (0.08µg/mL ± 0.11 vs 0.02 ± 0.10, p < 0.009) and decrement of L-homocysteine (-70.7 ± 85.0 vs -39.3 ± 69.4, p < 0.0168) were greater than those of the control group. Global DNA methylation was significantly increased in the K-diet group (6.70 ± 3.02% to 9.45 ± 3.69, p < 0.0001) but not in the control group. A K-diet high in one-carbon nutrients can enhance the global DNA methylation status, suggesting an epigenetic mechanism by which the K-diet conveys health effects. Trial registration Korean Clinical Trial Registry (trial number: KCT0005340, 24/08/2020, retrospectively registered).

Epigenetics in etiopathology of hyperprolactinemia

Aim: Epigenetic alterations have been reported in patients with pituitary tumors and those on antipsychotic drugs, which are also responsible for hyperprolactinemia. This suggests a possible role of epigenetics in the etiopathology of hyperprolactinemia. Methods: The study recruited 83 hyperprolactinemia cases with prolactin &gt; 100 ng/mL and 65 controls. Global DNA methylation status was studied by MethylFlash Methylated DNA Quantification Kit and genome-wide methylation analysis (GWMA) by Infinium Methylation EPIC BeadChip 850K array. Results: Hyperprolactinemia cases showed significant global DNA hypermethylation compared to controls. Around 66.67% of hypomethylated and 12.9% of hypermethylated cases were on antipsychotics. Gene enrichment analysis of 5-cytosine-phosphate-guanine-3 (CpG) site-associated genes demonstrated significantly enriched major histocompatibility complex (MHC)-related protein classes and cellular components. Conclusions: The study suggested the role of epigenetics in the etiopathology of hyperprolactinemia.

Improved prognostic stratification of patients with isocitrate dehydrogenase-mutant astrocytoma

Prognostic factors and standards of care for astrocytoma, isocitrate dehydrogenase (IDH)-mutant, CNS WHO grade 4, remain poorly defined. Here we sought to explore disease characteristics, prognostic markers, and outcome in patients with this newly defined tumor type. We determined molecular biomarkers and assembled clinical and outcome data in patients with IDH-mutant astrocytomas confirmed by central pathology review. Patients were identified in the German Glioma Network cohort study; additional cohorts of patients with CNS WHO grade 4 tumors were identified retrospectively at two sites. In total, 258 patients with IDH-mutant astrocytomas (114 CNS WHO grade 2, 73 CNS WHO grade 3, 71 CNS WHO grade 4) were studied. The median age at diagnosis was similar for all grades. Karnofsky performance status at diagnosis inversely correlated with CNS WHO grade (p < 0.001). Despite more intensive treatment upfront with higher grade, CNS WHO grade was strongly prognostic: median overall survival was not reached for grade 2 (median follow-up 10.4 years), 8.1 years (95% CI 5.4–10.8) for grade 3, and 4.7 years (95% CI 3.4–6.0) for grade 4. Among patients with CNS WHO grade 4 astrocytoma, median overall survival was 5.5 years (95% CI 4.3–6.7) without (n = 58) versus 1.8 years (95% CI 0–4.1) with (n = 12) homozygous CDKN2A deletion. Lower levels of global DNA methylation as detected by LINE-1 methylation analysis were strongly associated with CNS WHO grade 4 (p < 0.001) and poor outcome. MGMT promoter methylation status was not prognostic for overall survival. Histomolecular stratification based on CNS WHO grade, LINE-1 methylation level, and CDKN2A status revealed four subgroups of patients with significantly different outcomes. In conclusion, CNS WHO grade, global DNA methylation status, and CDKN2A homozygous deletion are prognostic in patients with IDH-mutant astrocytoma. Combination of these parameters allows for improved prediction of outcome. These data aid in designing upcoming trials using IDH inhibitors.

Relationship between hysterectomy and global DNA methylation levels in peripheral blood: an exploratory follow-up study

ObjectiveThe present study aims to understand the relationship between hysterectomy and peripheral blood leukocyte (PBL) global DNA methylation independently and in light of selected biochemicals (vitamin B12, folate, homocysteine). Material and methodsFor the present population-based follow-up study, a total of 616 women aged 30–70 years were recruited from Haryana, India. Recruited participants underwent a baseline assessment, which included the determination of menopausal and hysterectomy status and estimation of vitamin B12, folate, homocysteine, and PBL global DNA methylation (5mC) levels. The 5mC levels were analyzed using ELISA-based colorimetric technique. Participants with no history of hysterectomy were followed up after 8 years, and their current menopausal and hysterectomy statuses were determined. ResultThe median PBL 5mC level of the group with hysterectomy was found to be significantly lower than that of those without hysterectomy in the baseline assessment (PBL 5mC = 0.47 vs. 0.74, respectively; p-value = 0.016). However, there was no significant difference in baseline median PBL 5mC levels between women who eventually underwent hysterectomy and those who did not. When stratified for biochemical levels, the trend of PBL global DNA hypomethylation in the hysterectomy group, compared to the no-hysterectomy group, was statistically significant only within the normal folate group. ConclusionThis study suggests a potential association between hysterectomy (or related factors) and global DNA hypomethylation. Further research is warranted to validate the findings of the present study and to advance the existing knowledge regarding the epigenetic implications of hysterectomy.

Aging and the impact of global DNA methylation, telomere shortening, and total oxidative status on sarcopenia and frailty syndrome

Aging is a biological event that influences many organs and systems. Both sarcopenia and frailty syndrome refer to geriatric conditions with overlapping phenotypes. Many mechanisms are involved in the aging process such as DNA methylation telomeres which are susceptible to oxidative stress, and inflammations which result in telomere shortening, leading to chromosomal instability. The study aimed to determine the associations between these processes, frailty and sarcopenia syndrome. Global DNA methylation was analyzed using the ELISA method. Telomere length was analyzed using qPCR. Total oxidative status (TOS) was analyzed using a colorimetric method. The present study revealed that the main factor affecting methylation, telomeres length and level of total oxidant stress was age.

Aberrant Expression of TET2 Accounts for DNA Hypomethylation in Varicocele.

Epigenetic modifications such as DNA methylation play a key role in male infertility etiology. This study aimed to explore the global DNA methylation status in testicular spermatogenic cells of varicocele-induced rats and consider their semen quality, with a focus on key epigenetic marks, namely 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC), as well as the mRNA and proteins of ten-eleven translocation (TET) methylcytosine dioxygenases 1-3. In this experimental study, 24 mature male Wistar rats (8 in each group) were assigned amongst the control, sham, and varicocele groups. Sperm quality was assessed, and DNA methylation patterns of testicular spermatogenic cells were investigated using reverse transcription-polymerase chain reaction (RT-PCR), western blot, and immunofluorescence techniques. Sperm parameters, chromatin and DNA integrity were significantly lower, and sperm lipid peroxidation significantly increased in varicocele-induced rats in comparison with control rats. During spermatogenesis in rat testis, 5-mC and 5-hmC epigenetic marks, and TET1-3 mRNA and proteins were expressed. In contrast to the 5-mC fluorescent signal which was presented in all testicular cells, the 5-hmC fluorescent signal was presented exclusively in spermatogonia and a few spermatids. In varicocele-induced rats, the 5-mC signal decreased in all cells within the tubules, whereas a strong signal of 5-hmC was detected in seminiferous tubules compared to the control group. As well, the levels of TET2 mRNA and protein expression were significantly upregulated in varicocele-induced rats in comparison with the control group. Also, our results showed that the varicocele-induced animals exhibited strong fluorescent signals of TET1-3 in testicular cells, whereas weak fluorescent signals were identified in the seminiferous tubules of the control animals. Consequently, we showed TET2 upregulation and the 5-hmC gain at testicular levels are associated with varicocele and sperm quality decline, and therefore they can be exploited as potential biomarkers of spermatogenesis.

Neuroprotective effects of oxytocin against ischemic stroke in rats by blocking glutamate release and CREB-mediated DNA hypermethylation

Glutamate plays a crucial role in cognitive impairments after ischemic stroke. There is a scarcity of information about how glutamate-induced activation of cAMP-response element binding (CREB) signaling pathway regulates both the negative and positive regulators of synaptic plasticity. Recent studies have demonstrated the involvement of prominent epigenetic repressors, such as MeCP2 and DNMTs, in stroke. Neuroprotective effects of oxytocin against ischemia have been previously reported, while the underlying mechanism is still elusive. In this research, the possible role of CREB-mediated DNA hypermethylation and the potential mechanism of oxytocin in a rat model of permanent middle cerebral artery occlusion (pMCAO) were assessed. Adult male Sprague-Dawley rats were pretreated with intraperitoneal injection of oxytocin at the onset of pMCAO. The effects of oxytocin on spines and the expression levels of synaptic genes were determined. The regulatory effects of oxytocin on glutamate level, N-methyl-D-aspartate receptors (NMDARs), its downstream CREB pathway, and global or gene-specific DNA methylation status were evaluated by immunofluorescence, co-immunoprecipitation, and chromatin immunoprecipitation, respectively. We found that CREB could act as a common transcription factor for MeCP2 and DNMT3B after ischemic stroke. Oxytocin dose-dependently deactivated NR2B-related CaM-CREB pathway and inhibited DNA hypermethylation at the CpG islands of Ngf gene in pMCAO-operated rats. Moreover, oxytocin prevented pMCAO-induced reduction in the number of spines and neural cells. DNA hypermethylation in Ngf gene contributed to the cognitive deficits post-stroke. The neuroprotective effects of oxytocin against ischemia could be attributed to inhibiting glutamate release, providing additional evidence on the mechanism of oxytocin against ischemic stroke.

Abstract 033: Innate Lymphoid Cells Mediate Hypertension In T Cell Deficient Hosts

T cells have been shown to contribute to hypertension, however, hypertension occurs in settings of T cell deficiency, such as human immunodeficiency virus infection and following chemotherapy. We studied two colonies of RAG-1 -/- mice with disparate responses to angiotensin II (Ang II) infusion. Ang II increased both systolic and diastolic pressure in RAG-1 -/- mice from Jackson labs (RAG-1 -/-US ) but had no effect in a colony of RAG-1 -/- mice housed at our Pozzilli facility (RAG-1 -/-POZ ) for the past 14 years (SBPs 169 ± 2 vs 114 ± 3 mmHg, p &lt; 0.003). While both lacked T and B cells, the RAG-1 -/-US mice exhibited a striking expansion of natural killer and both type 1 and type 3 innate lymphoid cells, while the RAG-1 -/-POZ mice did not. In RAG-1 -/-US mice, NK cells and ILC1s produced IFNγ, while ILC3s produced IL-17A. Immunoclearing of IL-17A, but not IFNγ prevented the hypertension in RAG-1 -/-US mice. There were differences in global gene expression and DNA methylation status in NK1.1 + /NKp46 + cells between these two colonies and notably β2-AdR and IL-10 expression was significantly lower in RAG-1 -/-US mice. Knockdown of the β2-AdR using intra-splenic infusion of siRNA in RAG-1 -/-POZ mice led to a hypertensive response resembling that observed in wild type and RAG-1 -/-US mice. We also found striking differences in DNA methylation patterns in innate lymphoid cells of RAG-1 -/-US vs RAG-1 -/-POZ mice and treatment with the DNA methyltransferase inhibitor 5-azacytidine prevented hypertension in RAG-1 -/-US mice. Single cell sequencing showed that 5-azacytidine also reduced splenic populations of NK and ILC3 cells and reduced the presence of the transcription factor RORγt, which defines ILC3s. Ang II infusion caused only a transient elevation of blood pressure in NSG/MHCI/II -/- mice that lack T cells and innate lymphoid cells but led to sustained hypertension following adoptive transfer of either T cells or NK1.1 + /NKp46 + cells to these animals. We conclude that DNA methylation likely modulates expansion of NK and innate lymphoid cells. Either T cells or innate lymphoid cells can contribute to hypertension, and the latter can compensate by serving as a source of cytokines like IL-17A when T cells are deficient.

Epigenome-wide association study identifies Vogt-Koyanagi-Harada disease-associated DNA methylation loci in Chinese

DNA methylation is one of the important epigenetic mechanisms for modulating gene expression. By performing a genome-wide methylation association analysis of whole peripheral blood from 60 Vogt-Koyanagi-Harada disease (VKH) patients and 60 healthy controls, we depicted the global DNA methylation status of VKH disease. Further pyrosequencing validation in 160 patients and 159 controls identified 3 aberrant CpG sites in HLA gene regions including cg04026937 and cg18052547 (located in HLA-DRB1 region), and cg13778567 (HLA-DQA1). We also identified 9 aberrant CpG sites in non-HLA gene regions including cg13979407, cg21075643, cg24290586, cg10135747 and cg22707857 (BTNL2), cg22155039 (NOTCH4), cg02605387 (TNXB), cg06255004 (AGPAT2) and cg18855195 (RIBC2). Increased mRNA levels of BTNL2, NOTCH4 and TNXB were identified in VKH patients when compared with healthy controls, consistent with the hypomethylated CpG status in these gene regions. Moreover, seven aberrantly methylated CpG sites may serve as a diagnostic marker for VKH disease (AUC = 84.95%, 95%CI: 79.49%–90.41%).

Can Advanced paternal age affect global DNA methylation of human spermatozoa and ICSI outcome?

This study was performed to (I) evaluate the potential effect of advanced paternal age on global DNA methylation on spermatozoa, and (II) to investigate the association between the intracytoplasmic sperm injection (ICSI) outcomes, semen parameters, and advanced paternal age. This study comprised 230 semen samples collected from males with a mean age of 38.2 ± 8.5 years. The medical records were used to gather the medical information related to the female partner. The participants were divided into three groups depending on males' age: (age < 30; n = 50 "21.8%", age = 30-40; n = 90 "39.1%", and age > 40; n = 90 "39.1%"). The DNA was extracted from purified spermatozoa; then the sperm global DNA methylation, sperm DNA fragmentation, and chromatin decondensation were evaluated by an ELISA, TUNEL, and Chromomycin A3 staining, respectively. A significant variation has been found in the age of males included in this study (P < 0.001). A significant reduction has been observed in sperm count, total motility, and non-progressive motility in the older group compared to the younger group (P < 0.001). Additionally, a significant elevation in chromatin decondensation level, DNA fragmentation level, and global DNA methylation of spermatozoa in the older age group (P < 0.001) has been found. A significant positive correlation has been detected between the percentage of non-motile sperm, sperm chromatin decondensation, DNA fragmentation, global DNA methylation status, and paternal age (P < 0.001). This study pointed out that advanced paternal age increases the DNA fragmentation, chromatin decondensation, and global DNA methylation level in human spermatozoa which negatively affects the ICSI outcomes in couples undergoing ICSI cycles.

Identification of DNA Methylation Changes in European Beech Seeds during Desiccation and Storage.

Ageing and deterioration of seeds is a major problem for the maintenance of seed quality and viability during long-term storage. Prediction of early stages of seed deterioration in order to point out the plantlets' regeneration time is a major challenge of successful storage. In preserved seeds, damages accumulate within cells at the rate mainly related to their moisture content and temperature of storage. Current research reveals global alterations in DNA methylation in lipid-rich intermediate seeds during desiccation and storage at various regimes covering nonoptimal and optimal conditions. We show for the first time that monitoring of 5-methylcytosine (m5C) level in seeds can be used as a truly universal viability marker regardless of postharvest category of seeds and their composition. For seeds stored up to three years, in varied conditions, moisture content, temperature, and time of storage had significant influence on seedling emergence and DNA methylation (p < 0.05). Similarities among lipid-rich intermediate and orthodox seeds regarding different reactions of embryonic axes and cotyledons to desiccation are newly revealed. Along with previous studies on seeds dramatically different in desiccation tolerance (recalcitrant vs. orthodox), results regarding lipid-rich seeds positioned in-between (intermediate) prove that maintaining global DNA methylation status is crucial for maintaining seed viability.

Optical nanoscopy approach to unveil chromatin alterations implicated in neuroblastoma transformation.

Chromatin organization is a well-orchestrated mechanism regulating cellular physiology and its changes are associated with the onset of many diseases, including cancer. Neuroblastoma (NB) is the most common extracranial tumor in childhood, and it shows remarkable heterogeneity in the phenotypes and evolutionary patterns. Although the molecular mechanisms of this heterogeneity are still unclear, the impairment of the “epigenetic machinery” and the consequent chromatin reorganization might play an important role. We aim to assess the possible alterations in chromatin nanoscale architecture correlated with NB transformation using NB cells genetically engineered to overexpress the non-coding RNA NDM29, which promotes differentiation of tumor cells into a neuronal lineage. In both malignant NB cells (Mock) and neuron-like cells (S1.1), we explored chromatin organization and nuclear architecture by optical nanoscale microscopy using both confocal and stimulation emission depletion (STED) imaging methods, in parallel with molecular biology analyses. We characterized the nuclear 3D morphology of Mock vs. S1.1 cells by measuring volume, shape, and circularity of the nuclei as well as chromatin compaction and distribution. We imaged the immunolabeled histone H3 modifications (H3K9 trimethylation and H3K9 acetylation) to characterize chromatin regions typically associated with highly and poorly condensed chromatin, respectively. In parallel, we quantified the global DNA methylation status by measuring the levels of 5-methylcytosine (5-mC) using the enzyme-linked immunosorbent assay (ELISA) MethylFlash Global DNA. Comparing Mock vs. S1.1 cells, we observed (i) significant remodeling of nuclear morphometry; (ii) marked rearrangement of chromatin domains rich in highly-acetylated and -methylated H3K9; (iii) changes in average chromatin compaction and DNA methylation. Altogether, the results point to an involvement of epigenetic mechanisms which may sustain the chromatin remodeling during NB malignant transformation, paving the way towards new prognostic and therapeutic approaches and understanding chromatin remodeling in physiological/pathological processes.

NLRP13 inflammasome complex is hypermethylated in familial Mediterranean fever and global methylation correlates with the disease severity.

Familial Mediterranean fever (FMF) is an autoinflammatory disease caused by variations in the MEFV gene, which encodes the pyrin protein, a member of the inflammasomes. Despite the complex pathogenesis of FMF, epigenetic changes also play roles in the disease progression. In our previous study, we observed a relationship between NLRP13, which is one of the members of the inflammasome complex and has a pyrin domain in its structure, and the MEFV gene using the STRING database. In this study, we examined NLRP13 expression and methylation status in 40 patients with FMF attack and 20 healthy individuals. We then investigated the global DNA methylation status of patients with FMF in the attack period and control groups. We further examined the relationship between the clinical manifestation and global methylation as well as NLRP13 gene expression of patients with FMF and healthy individuals. As a result, we showed that hypomethylation in patients with FMF leads to different clinical outcomes in terms of disease severity. In addition, the data indicated that NLRP13 inflammasome is epigenetically controlled in patients with FMF and the presence of amyloidosis may affect the hypermethylation of this gene. Moreover, NLRP13 was silenced because of the hypermethylation of the promoter. The increase of methylation level at the promoter region participated in the inactivation of NLRP13. In the current study, we not only found a new gene that plays a role in the pathogenesis of FMF disease, but also new evidence for the epigenetic regulation of the disease.

The suppressor of cytokine signaling-1 (SOCS1) gene polymorphism and promoter methylation correlate with the course of COVID-19

ABSTRACT The suppressor of the cytokine signaling-1 (SOCS1) gene is a short sequence located on chromosome 16 that functions to induce an appropriate immune response and is an essential physiological regulator of interferon (IFN) signaling. In addition to comparing the global DNA and SOCS1 gene promoter methylation status between our patients with coronavirus disease 2019 (COVID-19) and healthy controls, this study demonstrates the effect of the SOCS1 rs33989964 polymorphism on patients with COVID-19. The study group included 139 patients diagnosed with COVID-19 in our hospital’s clinics between June and December 2020, and the control group included 78 healthy individuals. After comparing the initial gene polymorphisms of the patients with the healthy control group, three separate clinical subgroups were formed. The gene polymorphism distribution and the methylation status of SOCS1 were examined in these clinical subgroups. Hypomethylation of the SOCS1 gene was observed in the COVID-19 patient group compared to the healthy control group (p = 0.001). Between the patients divided into two separate clinical subgroups, those with severe and mild infections, the Del/Del genotype of the SOCS1 gene was more common in patients with severe infection than in patients with mild infection (p = 0.018). Patients with the CA/CA and CA/Del genotypes were 0.201 times more likely to have a severe infection (95% CI: 0.057–0.716, p = 0.007). Having a non-Del/Del genotype was a protective factor against severe infection. The effect of the SOCS1 rs33989964 polymorphism and methylation status of the SOCS1 gene throughout the COVID-19 pandemic could be significant contributions to the literature.

Global and Regional DNA methylation silencing of PPARγ Associated with Glioblastoma Multiforme Pathogenesis.

The relationship between peroxisome proliferator-activated receptor gamma (PPARγ) expression level and epigenetic modifications occurring in glioblastoma multiforme (GBM) pathogenesis is largely unknown. Herein, we examine the association of PPARγ expression with its promoter and genomic global DNA methylation status, as well as DNA methyltransferases (DNMTs) gene expression in GBM patients. We examined the patterns of promoter methylation and PPARγ expression in 26 GBM tissues and 13 adjacent non-tumor tissues by methylation-specific PCR (MSP), real-time PCR, and ELISA, respectively. Also, we examined the genomic global 5-methyl cytosine levels and DNMTs gene expression using ELISA and real-time PCR methods, respectively. We found that hypermethylation on a specific region of the PPARγ promoter is significantly associated with the downregulation of the PPARγ gene and protein level in GBM patients. Interestingly, the amount of 5-methyl cytosine level was significantly reduced in GBM patients and positively correlated with PPARγ protein expression. Furthermore, the expression level of DNMT1, DNMT3A, and 3B were upregulated in GBM patients and the average expression level of all three DNMTs was positively correlated with tumor area. Also, we found that tumors from cortical regions exhibited a higher global DNA hypomethylation and PPARγ hypermethylation was related to the increase in GBM risk. Our study demonstrated that global DNA methylation and PPARγ epigenetic silencing is associated with the GBM risk. Our data provide a novel molecular mechanistic insight into epigenetic silencing of PPARγ in GBM patients that may be relevant as a key tumor marker for GBM pathogenesis.

Contribution of DNA methylation profiling to the reclassification of a variant of uncertain significance in the KDM5C gene

KDM5C encodes a demethylase of the histone H3 lysine 4 residue, involved in chromatin regulation and gene expression. Hemizygous KDM5C pathogenic variants cause X-linked intellectual disability of Claes-Jensen type. Because of its mode of inheritance and the low specificity of the clinical phenotype, interpretation of variants can be difficult, hence the need for functional studies and biomarkers specific to this disorder. We present the case of a male patient with intellectual disability, behavioral abnormalities and subtle dysmorphic features, in which genetic investigation identified a hemizygous novel missense KDM5C variant of uncertain significance (VUS), inherited from his asymptomatic mother and present in his paucisymptomatic sister. We assessed the global genomic DNA methylation status from a whole blood sample of the proband. Global DNA methylation profiling specifically identified the recently discovered epi-signature of Claes-Jensen syndrome. This result served as a biomarker which independently highlighted KDM5C as the cause of the disorder in this patient. Because of the X-linked mode of inheritance, variant reclassification had a high impact on genetic counseling in this family. This example highlights the value of global methylome profiling in situations of variants of uncertain significance in genes with a known specific epi-signature.

Association between toxic and essential metals in blood and global DNA methylation among electronic waste workers in Agbogbloshie, Ghana.

Aberrant global DNA methylation status is a known biomarker for increased disease risk, especially cancer. There is little published data on the association between toxic and essential metal mixtures and global DNA methylation in electronic waste (e-waste) workers. We aimed to establish the association between toxic and essential metals in blood and the effect of their interactions on global DNA methylation among e-waste recyclers and a reference group in Ghana. We used ICP-MS to measure the level of five metals (Se, Zn, Mn, Cd, and Pb) in the blood of 100 e-waste workers and 51 controls. We quantified blood DNA methylation levels of LINE-1 as an indicator of global DNA methylation. Cd, Mn, and Se levels were significantly higher in the reference group than in e-waste workers. Only Pb was significantly higher in the e-waste workers compared to the controls. Our linear regression analysis results showed a significant inverse association between Zn and LINE-1 DNA methylation (βZn = - 0.912; 95% CI, - 1.512, - 0.306; p = 0.003) which corresponds to a 0.009 decrease in %LINE-1 methylation (95% CI, - 0.015, - 0.003; p = 0.003) for a 1% increase in Zn concentration. Potential interactions between Cd and Zn on global DNA methylation were observed. In summary, co-exposure to toxic and essential metals is associated with global (LINE-1) DNA methylation.

Global DNA Methylation Status in Relation to Resistance Training with High vs Low Loads to Failure

ObjectiveOur objective was to determine how global DNA methylation status of skeletal muscle differs with resistance training (RT) to failure in trained participants using either 80% of their estimated one‐repetition maximum (Est. 1‐RM) (80FAIL) or 30% of their Est. 1‐RM (30FAIL).HypothesesWe hypothesize there will be a significant decrease in global DNA methylation with both RT conditions, but that 30FAIL RT will elicit a greater magnitude of hypomethylation than 80FAIL RT.MethodsPreviously trained college‐aged males (n= 11, age 23 ± 4 years, percent fat 11.4 ± 6.4%, training experience 4 ± 3 years, squat strength relative to body weight 1.7 ± 0.3) voluntarily underwent two bouts of RT. Participants completed both the 80FAIL and 30FAIL conditions (separated by one week). For each bout of RT, participants completed 4 sets of back squats and 4 sets leg extensions with either the 80FAIL or 30FAIL training conditions. Muscle biopsies were collected from the vastus lateralis before (PRE), 3 hours (3hPOST), and 6 hours (6hrPOST) after each RT bout. DNA was then batch‐isolated from muscle tissue and submitted for analysis using the Illumina MethylationEPIC array.ResultsTotal number of repetitions performed were significantly higher for 30FAIL training vs 80FAIL training (p&lt; .001), however total training volume (sets x reps x load) was not significantly different between conditions (p= 0.571). Global methylation changes between PRE, 3hPOST, and 6hPOST are presented herein. In addition, significant differences between conditions are emphasized for each post‐exercise time point.ConclusionsWith this study we expand our understanding of how the manipulation of RT variables affect epigenetic modifications in skeletal muscle.

Global DNA methylation and increased DNMT3A expression in multiple myeloma patients.

The aim of this study was to compare the expression profile of selected DNA methyltransferases and global DNA methylation status in patients with different phases of multiple myeloma (MM) . For the analysis, different cellular populations including unsorted myeloma cells and a set of plasma cells purified by relevant antibodies were used. Consequently, laboratory data were compared to patients' clinical data. For the analysis, unsorted bone marrow cell population of 44 MM patients (30 newly diagnosed, 9 relapsed and 5 patients in remission) and a set of 8 patients' samples of sorted plasma cells were used. We used commercially available RNA isolated from BM of 3 healthy individuals as control samples. Expression analysis of three DNA methyltransferases - DNMT1, DNMT3A, and DNMT3B was performed by quantitative RT-PCR and the patient global DNA methylation profiles were detected by colorimetric assay. Unchanged DNMT1 expression was detected in the selected cohort of patients. Normalized DNMT3A gene expression was globally higher in comparison with controls in unsorted and sorted cell populations. Low (0.08-1.81%) global DNA methylation status in unsorted samples of multiple myeloma patients did not correlate either with expression profiles of monitored DNA methyltransferases or with the stages of MM based on Durie-Salmon and International Staging System. This is the first comparative study between DNA methyltransferases expression profiles and global DNA methylation status in different phases of multiple myeloma patients. No significant correlation between the level of global methylation and the clinical stage of the unsorted cell population of patients with multiple myeloma was registered. Overexpression of the DNMT3A gene occurred in both sorted and unsorted cell populations of patients with multiple myeloma. This fact highlights the DNMT3A as a potential marker of multiple myeloma tumor progression. Moreover, we demonstrated comparable results in the expression of DNA methyltransferases in both sorted and unsorted cell populations. This is a promising result from the methodical point of view because when compared to samples of unsorted multiple myeloma cells, samples of sorted cells bring reduction of the number of possible analyses performed.

Association of air pollution and homocysteine with global DNA methylation: A population-based study from North India.

BackgroundAnthropogenic air pollution has been implicated in aberrant changes of DNA methylation and homocysteine increase (>15μM/L). Folate (<3 ng/mL) and vitamin B12 (<220 pg/mL) deficiencies also reduce global DNA methylation via homocysteine increase. Although B-vitamin supplements can attenuate epigenetic effects of air pollution but such understanding in population-specific studies are lacking. Hence, the present study aims to understand the role of air pollution, homocysteine, and nutritional deficiencies on methylation.MethodsWe examined cross-sectionally, homocysteine, folate, vitamin B12 (chemiluminescence) and global DNA methylation (colorimetric ELISA Assay) among 274 and 270 individuals from low- and high- polluted areas, respectively, from a single Mendelian population. Global DNA methylation results were obtained on 254 and 258 samples from low- and high- polluted areas, respectively.ResultsSignificant decline in median global DNA methylation was seen as a result of air pollution [high-0.84 (0.37–1.97) vs. low-0.96 (0.45–2.75), p = 0.01]. High homocysteine in combination with air pollution significantly reduced global DNA methylation [high-0.71 (0.34–1.90) vs. low-0.93 (0.45–3.00), p = 0.003]. Folate deficient individuals in high polluted areas [high-0.70 (0.37–1.29) vs. low-1.21 (0.45–3.65)] showed significantly reduced global methylation levels (p = 0.007). In low polluted areas, despite folate deficiency, if normal vitamin B12 levels were maintained, global DNA methylation levels improved significantly [2.03 (0.60–5.24), p = 0.007]. Conversely, in high polluted areas despite vitamin B12 deficiency, if normal folate status was maintained, global DNA methylation status improved significantly [0.91 (0.36–1.63)] compared to vitamin B12 normal individuals [0.54 (0.26–1.13), p = 0.04].ConclusionsHigh homocysteine may aggravate the effects of air pollution on DNA methylation. Vitamin B12 in low-polluted and folate in high-polluted areas may be strong determinants for changes in DNA methylation levels. The effect of air pollution on methylation levels may be reduced through inclusion of dietary or supplemented B-vitamins. This may serve as public level approach in natural settings to prevent metabolic adversities at community level.