Advances in microfluidic-based DNA methylation analysis

DNA methylation has been extensively investigated in recent years,not least because of its known relationship with various diseases.Progress in analytical methods can greatly increase the relevance of DNA methylation studies to both clinical medicine and scientific research.Microflu-idic chips are excellent carriers for molecular analysis,and their use can provide improvements from multiple aspects.On-chip molecular analysis has received extensive attention owing to its advantages of portability,high throughput,low cost,and high efficiency.In recent years,the use of novel microfluidic chips for DNA methylation analysis has been widely reported and has shown obvious superiority to conventional methods.In this review,wefirst focus on DNA methylation and its applications.Then,we discuss advanced microfluidic-based methods for DNA methylation analysis and describe the great progress that has been made in recent years.Finally,we summarize the advantages that microfluidic technology brings to DNA methylation analysis and describe several challenges and perspectives for on-chip DNA methylation analysis.This review should help researchers improve their understanding and make progress in developing microfluidic-based methods for DNA methylation analysis.

Association of DNA methylation/demethylation with the functional outcome of stroke in a hyperinflammatory state

Inflammation is closely related to stroke prognosis, and high inflammation status leads to poor functional outcome in stroke. DNA methylation is involved in the pathogenesis and prognosis of stroke. However, the effect of DNA methylation on stroke at high levels of inflammation is unclear. In this study, we constructed a hyperinflammatory cerebral ischemia mouse model and investigated the effect of hypomethylation and hypermethylation on the functional outcome. We constructed a mouse model of transient middle cerebral artery occlusion and treated the mice with lipopolysaccharide to induce a hyperinflammatory state. To investigate the effect of DNA methylation on stroke, we used small molecule inhibitors to restrain the function of key DNA methylation and demethylation enzymes. 2,3,5-Triphenyltetrazolium chloride staining, neurological function scores, neurobehavioral tests, enzyme-linked immunosorbent assay, quantitative reverse transcription PCR and western blot assay were used to evaluate the effects after stroke in mice. We assessed changes in the global methylation status by measuring DNA 5-mc and DNA 5-hmc levels in peripheral blood after the use of the inhibitor. In the group treated with the DNA methylation inhibitor, brain tissue 2,3,5-triphenyltetrazolium chloride staining showed an increase in infarct volume, which was accompanied by a decrease in neurological scores and worsening of neurobehavioral performance. The levels of inflammatory factors interleukin 6 and interleukin-1 beta in ischemic brain tissue and plasma were elevated, indicating increased inflammation. Related inflammatory pathway exploration showed significant overactivation of nuclear factor kappa B. These results suggested that inhibiting DNA methylation led to poor functional outcome in mice with high inflammation following stroke. Further, the effects were reversed by inhibition of DNA demethylation. Our findings suggest that DNA methylation regulates the inflammatory response in stroke and has an important role in the functional outcome of hyperinflammatory stroke.

Unveiling DNA methylation in Alzheimer’s disease:a review of array-based human brain studies

The intricacies of Alzheimer’s disease pathogenesis are being increasingly illuminated by the exploration of epigenetic mechanisms,particularly DNA methylation.This review comprehensively surveys recent human-centered studies that investigate whole genome DNA methylation in Alzheimer’s disease neuropathology.The examination of various brain regions reveals distinctive DNA methylation patterns that associate with the Braak stage and Alzheimer’s disease progression.The entorhinal cortex emerges as a focal point due to its early histological alterations and subsequent impact on downstream regions like the hippocampus.Notably,ANK1 hypermethylation,a protein implicated in neurofibrillary tangle formation,was recurrently identified in the entorhinal cortex.Further,the middle temporal gyrus and prefrontal cortex were shown to exhibit significant hypermethylation of genes like HOXA3,RHBDF2,and MCF2L,potentially influencing neuroinflammatory processes.The complex role of BIN1 in late-onset Alzheimer’s disease is underscored by its association with altered methylation patterns.Despite the disparities across studies,these findings highlight the intricate interplay between epigenetic modifications and Alzheimer’s disease pathology.Future research efforts should address methodological variations,incorporate diverse cohorts,and consider environmental factors to unravel the nuanced epigenetic landscape underlying Alzheimer’s disease progression.

DNA methylation in poultry:a review

As an important epigenetic modification,DNA methylation is involved in many biological processes such as animal cell differentiation,embryonic development,genomic imprinting and sex chromosome inactivation.As DNA methylation sequencing becomes more sophisticated,it becomes possible to use it to solve more zoological problems.This paper reviews the characteristics of DNA methylation,with emphasis on the research and application of DNA methylation in poultry.

Rice melatonin deficiency causes premature leaf senescence via DNA methylation regulation

In a study of DNA methylation changes in melatonin-deficient rice mutants,mutant plants showed premature leaf senescence during grain-filling and reduced grain yield.Melatonin deficiency led to transcriptional reprogramming,especially of genes involved in chlorophyll and carbon metabolism,redox regulation,and transcriptional regulation,during dark-induced leaf senescence.Hypomethylation of mCG and mCHG in the melatonin-deficient rice mutants was associated with the expression change of both protein-coding genes and transposable element-related genes.Changes in gene expression and DNA methylation in the melatonin-deficient mutants were compensated by exogenous application of melatonin.A decreased S-adenosyl-L-methionine level may have contributed to the DNA methylation variations in rice mutants of melatonin deficiency under dark conditions.

Comparative DNA methylation reveals epigenetic adaptation to high altitude in snub-nosed monkeys

DNA methylation plays a crucial role in environmental adaptations.Here,using whole-genome bisulfite sequencing,we generated comprehensive genome-wide DNA methylation profiles for the high-altitude Yunnan snub-nosed monkey(Rhinopithecus bieti)and the closely related golden snub-nosed monkey(R.roxellana).Our findings indicated a slight increase in overall DNA methylation levels in golden snub-nosed monkeys compared to Yunnan snub-nosed monkeys,suggesting a higher prevalence of hypermethylated genomic regions in the former.Comparative genomic methylation analysis demonstrated that genes associated with differentially methylated regions were involved in membrane fusion,vesicular formation and trafficking,hemoglobin function,cell cycle regulation,and neuronal differentiation.These results suggest that the high-altitude-related epigenetic modifications are extensive,involving a complete adaptation process from the inhibition of single Ca^(2+)channel proteins to multiple proteins collaboratively enhancing vesicular function or inhibiting cell differentiation and proliferation.Functional assays demonstrated that overexpression or down-regulation of candidate genes,such as SNX10,TIMELESS,and CACYBP,influenced cell viability under stress conditions.Overall,this research suggests that comparing DNA methylation across closely related species can identify novel candidate genomic regions and genes associated with local adaptations,thereby deepening our understanding of the mechanisms underlying environmental adaptations.

Effectiveness of fecal DNA syndecan-2 methylation testing for detection of colorectal cancer in a high-risk Chinese population

BACKGROUND Colorectal cancer(CRC)is among the most prevalent and life-threatening malignancies worldwide.Syndecan-2 methylation(mSDC2)testing has emerged as a widely used biomarker for early detection of CRC in stool and serum samples.Cancer(CRC)is among the most prevalent and life-threatening malignancies worldwide.mSDC2 testing has emerged as a widely used biomarker for early detection of CRC in stool and serum samples.AIM To validate the effectiveness of fecal DNA mSDC2 testing in the detection of CRC among a high-risk Chinese population to provide evidence-based data for the development of diagnostic and/or screening guidelines for CRC in China.METHODS A high-risk Chinese cohort consisting of 1130 individuals aged 40-79 years was selected for evaluation via fecal mSDC2 testing.Sensitivity and specificity for CRC,advanced adenoma(AA)and advanced colorectal neoplasia(ACN)were determined.High-risk factors for the incidence of colorectal lesions were determined and a logistic regression model was constructed to reflect the efficacy of the test.RESULTS A total of 1035 high-risk individuals were included in this study according to established criteria.Among them,16 suffered from CRC(1.55%),65 from AA(6.28%)and 189 from non-AAs(18.26%);150 patients were diagnosed with polyps(14.49%).Diagnoses were established based upon colonoscopic and pathological examinations.Sensitivities of the mSDC2 test for CRC and AA were 87.50%and 40.00%,respectively;specificities were 95.61%for other groups.Positive predictive values of the mSDC2 test for CRC,AA and ACN were 16.09%,29.89%and 45.98%,respectively;the negative predictive value for CRC was 99.79%.After adjusting for other high-risk covariates,mSDC2 test positivity was found to be a significant risk factor for the occurrence of ACN(P<0.001).CONCLUSION Our findings confirmed that offering fecal mSDC2 testing and colonoscopy in combination for CRC screening is effective for earlier detection of malignant colorectal lesions in a high-risk Chinese population.

Advances in DNA methylation and its role in cytoplasmic male sterility in higher plants

The impact of epigenetic modifications like DNA methylation on plant phenotypes has expanded the possibilities for crop development.DNA methylation plays a part in the regulation of both the chromatin structure and gene expression,and the enzyme involved,DNA methyltransferase,executes the methylation process within the plant genome.By regulating crucial biological pathways,epigenetic changes actively contribute to the creation of the phenotype.Therefore,epigenome editing may assist in overcoming some of the drawbacks of genome editing,which can have minor off-target consequences and merely facilitate the loss of a gene’s function.These drawbacks include gene knockout,which can have such off-target effects.This review provides examples of several molecular characteristics of DNA methylation,as well as some plant physiological processes that are impacted by these epigenetic changes in the plants.We also discuss how DNA alterations might be used to improve crops and meet the demands of sustainable and environmentally-friendly farming.

DNA Methylation of KLRC1 and KLRC3 in Autoimmune Thyroiditis:Perspective of Different Water Iodine Exposure

Objective This study aimed to identify differentially methylated genes(DMGs) associated with natural killer cells in patients with autoimmune thyroiditis(AIT), focusing on the influence of varying water iodine exposure levels.Methods Participants were divided into categories based on median water iodine(MWI)concentrations: iodine-fortified areas(IFA, MWI < 10 μg/L), iodine-adequate areas(IAA, 40 ≤ MWI ≤ 100μg/L), and iodine-excessive areas(IEA, MWI > 300 μg/L). A total of 176 matched AIT cases and controls were recruited and divided into 89, 40, and 47 pairs for IFA, IAA, and IEA, respectively. DMGs were identified using 850K Bead Chip analysis for 10/10 paired samples. Validation of DNA methylation and m RNA expression levels of the DMGs was conducted using Methyl Target^(TM) and QRT-PCR for 176/176paired samples.Results KLRC1, KLRC3, and SH2D1B were identified as significant DMGs. Validation revealed that KLRC1 was hypomethylated and highly expressed, whereas KLRC3 was hypermethylated and highly expressed in individuals with AIT. Furthermore, KLRC1 was hypomethylated and highly expressed in both IFA and IEA.Conclusion The DNA methylation status of KLRC1 and KLRC3 may play crucial roles in AIT pathogenesis. Additionally, DNA methylation of KLRC1 seems to be influenced by different iodine concentrations in water.

Salsolinol as an RNA m~6A methylation inducer mediates dopaminergic neuronal death by regulating YAP1 and autophagy

Salsolinol(1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline,Sal)is a catechol isoquinoline that causes neurotoxicity and shares structural similarity with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine,an environmental toxin that causes Parkinson's disease.However,the mechanism by which Sal mediates dopaminergic neuronal death remains unclear.In this study,we found that Sal significantly enhanced the global level of N~6-methyladenosine(m~6A)RNA methylation in PC12 cells,mainly by inducing the downregulation of the expression of m~6A demethylases fat mass and obesity-associated protein(FTO)and alk B homolog 5(ALKBH5).RNA sequencing analysis showed that Sal downregulated the Hippo signaling pathway.The m~6A reader YTH domain-containing family protein 2(YTHDF2)promoted the degradation of m~6A-containing Yes-associated protein 1(YAP1)mRNA,which is a downstream key effector in the Hippo signaling pathway.Additionally,downregulation of YAP1 promoted autophagy,indicating that the mutual regulation between YAP1 and autophagy can lead to neurotoxicity.These findings reveal the role of Sal on m~6A RNA methylation and suggest that Sal may act as an RNA methylation inducer mediating dopaminergic neuronal death through YAP1 and autophagy.Our results provide greater insights into the neurotoxic effects of catechol isoquinolines compared with other studies and may be a reference for assessing the involvement of RNA methylation in the pathogenesis of Parkinson's disease.

Unraveling the relationship between histone methylation and nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease(NAFLD)poses a significant health challenge in modern societies due to shifts in lifestyle and dietary habits.Its complexity stems from genetic predisposition,environmental influences,and metabolic factors.Epigenetic processes govern various cellular functions such as transcription,chromatin structure,and cell division.In NAFLD,these epigenetic tendencies,especially the process of histone methylation,are intricately intertwined with fat accumulation in the liver.Histone methylation is regulated by different enzymes like methyltransferases and demethylases and influences the expression of genes related to adipogenesis.While early-stage NAFLD is reversible,its progression to severe stages becomes almost irreversible.Therefore,early detection and intervention in NAFLD are crucial,and understanding the precise role of histone methylation in the early stages of NAFLD could be vital in halting or potentially reversing the progression of this disease.

N6-methyladenosine methylation regulates the tumor microenvironment of Epstein-Barr virus-associated gastric cancer

BACKGROUND N6-methyladenosine(m6A)methylation modification exists in Epstein-Barr virus(EBV)primary infection,latency,and lytic reactivation.It also modifies EBV latent genes and lytic genes.EBV-associated gastric cancer(EBVaGC)is a distinctive molecular subtype of GC.We hypothesized EBV and m6A methylation regulators interact with each other in EBVaGC to differentiate it from other types of GC.AIM To investigate the mechanisms of m6A methylation regulators in EBVaGC to determine the differentiating factors from other types of GC.METHODS First,The Cancer Gene Atlas and Gene Expression Omnibus databases were used to analyze the expression pattern of m6A methylation regulators between EBVaGC and EBV-negative GC(EBVnGC).Second,we identified Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)functional enrichment of m6A-related differentially expressed genes.We quantified the relative abundance of immune cells and inflammatory factors in the tumor microenvironment(TME).Finally,cell counting kit-8 cell proliferation test,transwell test,and flow cytometry were used to verify the effect of insulin-like growth factor binding protein 1(IGFBP1)in EBVaGC cell lines.RESULTS m6A methylation regulators were involved in the occurrence and development of EBVaGC.Compared with EBVnGC,the expression levels of m6A methylation regulators Wilms tumor 1-associated protein,RNA binding motif protein 15B,CBL proto-oncogene like 1,leucine rich pentatricopeptide repeat containing,heterogeneous nuclear ribonucleoprotein A2B1,IGFBP1,and insulin-like growth factor 2 binding protein 1 were significantly downregulated in EBVaGC(P<0.05).The overall survival rate of EBVaGC patients with a lower expression level of IGFBP1 was significantly higher(P=0.046).GO and KEGG functional enrichment analyses showed that the immunity pathways were significantly activated and rich in immune cell infiltration in EBVaGC.Compared with EBVnGC,the infiltration of activated CD4+T cells,activated CD8+T cells,monocytes,activated dendritic cells,and plasmacytoid dendritic cells were significantly upregulated in EBVaGC(P<0.001).In EBVaGC,the expression level of proinflammatory factors interleukin(IL)-17,IL-21,and interferon-γ and immunosuppressive factor IL-10 were significantly increased(P<0.05).In vitro experiments demonstrated that the expression level of IGFBP1 was significantly lower in an EBVaGC cell line(SNU719)than in an EBVnGC cell line(AGS)(P<0.05).IGFBP1 overexpression significantly attenuated proliferation and migration and promoted the apoptosis levels in SNU719.Interfering IGFBP1 significantly promoted proliferation and migration and attenuated the apoptosis levels in AGS.CONCLUSION m6A regulators could remodel the TME of EBVaGC,which is classified as an immune-inflamed phenotype and referred to as a“hot”tumor.Among these regulators,we demonstrated that IGFBP1 affected proliferation,migration,and apoptosis.

Effects of maternal methyl donor intake during pregnancy on ileum methylation and function in an intrauterine growth restriction pig model

Background Intrauterine growth retardation(IUGR)affects intestinal growth,morphology,and function,which leads to poor growth performance and high mortality.The present study explored whether maternal dietary methyl donor(MET)supplementation alleviates IUGR and enhances offspring’s growth performance by improving intestinal growth,function,and DNA methylation of the ileum in a porcine IUGR model.Methods Forty multiparous sows were allocated to the control or MET diet groups from mating until delivery.After farrowing,8 pairs of IUGR and normal birth weight piglets from 8 litters were selected for sampling before suckling colostrum.Results The results showed that maternal MET supplementation tended to decrease the IUGR incidence and increased the average weaning weight of piglets.Moreover,maternal MET supplementation significantly reduced the plasma concentrations of isoleucine,cysteine,urea,and total amino acids in sows and newborn pig-lets.It also increased lactase and sucrase activity in the jejunum of newborn piglets.MET addition resulted in lower ileal methionine synthase activity and increased betaine homocysteine S-methyltransferase activity in the ileum of newborn piglets.DNA methylation analysis of the ileum showed that MET supplementation increased the methyla-tion level of DNA CpG sites in the ileum of newborn piglets.Down-regulated differentially methylated genes were enriched in folic acid binding,insulin receptor signaling pathway,and endothelial cell proliferation.In contrast,up-regulated methylated genes were enriched in growth hormone receptor signaling pathway and nitric oxide biosyn-thetic process.Conclusions Maternal MET supplementation can reduce the incidence of IUGR and increase the weaning litter weight of piglets,which may be associated with better intestinal function and methylation status.

Reduced non-CpG methylation is a potential epigenetic target after spinal cord injury

DNA methylation is a critical epigenetic regulator in the occurrence and development of diseases and is closely related to various functional responses in relation to spinal cord injury.To investigate the role of DNA methylation in spinal cord injury,we constructed a library with reduced-representation bisulfite sequencing data obtained at various time points(day 0-42)after spinal cord injury in mice.Global DNA methylation levels,specifically non-CpG(CHG and CHH)methylation levels,decreased modestly following spinal cord injury.Stages post-spinal cord injury were classified as early(day 0-3),intermediate(day7-14),and late(day 28-42)based on similarity and hie rarchical cluste ring of global DNA methylation patterns.The non-CpG methylation level,which included CHG and CHH methylation levels,was markedly reduced despite accounting for a minor proportion of total methylation abundance.At multiple genomic sites,including the 5’untranslated regions,promoter,exon,intron,and 3’untranslated regions,the non-CpG methylation level was markedly decreased following spinal cord injury,whereas the CpG methylation level remained unchanged at these locations.Approximately one-half of the differentially methylated regions were located in intergenic areas;the other differentially methylated regions in both CpG and non-CpG regions were cluste red in intron regions,where the DNA methylation level was highest.The function of genes associated with differentially methylated regions in promoter regions was also investigated.From Gene Ontology analysis results,DNA methylation was implicated in a number of essential functional responses to spinal cord injury,including neuronal synaptic connection creation and axon regeneration.Notably,neither CpG methylation nor non-CpG methylation was implicated in the functional response of glial or inflammatory cells.In summary,our work elucidated the dynamic pattern of DNA methylation in the spinal co rd following injury and identified reduced nonCpG methylation as an epigenetic target after spinal cord injury in mice.

Imprinting at the KBTBD6 locus involves species-specific m ternal methylation and monoallelic expression in livestock animals

Background The primary differentially methylated regions(DMRs) which are maternally hypermethylated serve as imprinting control regions(ICRs) that drive monoallelic gene expression, and these ICRs have been investigated due to their implications in mammalian development. Although a subset of genes has been identified as imprinted, in-depth comparative approach needs to be developed for identification of species-specific imprinted genes. Here, we examined DNA methylation status and allelic expression at the KBTBD6 locus across species and tissues and explored potential mechanisms of imprinting.Results Using whole-genome bisulfite sequencing and RNA-sequencing on parthenogenetic and normal porcine embryos, we identified a maternally hypermethylated DMR between the embryos at the KBTBD6 promoter Cp G island and paternal monoallelic expression of KBTBD6. Also, in analyzed domesticated mammals but not in humans, non-human primates and mice, the KBTBD6 promoter Cp G islands were methylated in oocytes and/or allelically methyl-ated in tissues, and monoallelic KBTBD6 expression was observed, indicating livestock-specific imprinting. Further analysis revealed that these Cp G islands were embedded within transcripts in porcine and bovine oocytes which coexisted with an active transcription mark and DNA methylation, implying the presence of transcription-dependent imprinting.Conclusions In this study, our comparative approach revealed an imprinted expression of the KBTBD6 gene in domesticated mammals, but not in humans, non-human primates, and mice which implicates species-specific evolution of genomic imprinting.

Mechanism of Wendan decoction in preventing obesity by regulating multiple signal pathway networks based on gene promoter methylation

Objective:To investigate the potential mechanism of Wendan decoction in obesity by screening target genes with promoter region methylation changes and constructing a multiple signaling pathways network based on promoter methylation.Methods:The methylation degree of Itgad,Col8a1,Adra2b,Jund,Rab2a,Wnt8b,Fzd9,B4galt7,Pik3cd,Creb1,Stard8,and Mmp1 in the abdominal adipose tissue of obese rats was determined using the Agena MassARRAY system.Western blot was performed to assess protein expression levels.Target genes were identified based on the methylation degree in the promoter region and protein expression.Enrichment analysis of signaling pathways was conducted to identify relevant target genes and obtain a multiple signaling pathway network associated with obesity.Core and terminal effector molecules in the pathway networks were selected as research targets for reverse transcription-polymerase chain reaction(RT-PCR)analysis.Results:Four genes(Adra2b,Creb1,Itgad,and Pik3cd)showed a degree of promoter methylation consistent with their respective protein expression levels.Among them,Adra2b,Creb1,and Pik3cd expression increased,while that of Itgad decreased.Enrichment analysis revealed that Creb1 and Pik3cd were involved in 6 signaling pathways related to obesity:tumor necrosis factor(TNF)signaling pathway,growth hormone synthesis/secretion and action,adenosine 5'-monophosphate-activated protein kinase(AMPK)signaling pathway,relaxin signaling pathway,cyclic nucleotide(cAMP)signaling pathway,and phosphatidylinositol 3-kinase/protein kinase B(PI3K/Akt)signaling pathway.Subsequently,a multiple signaling pathways network was constructed based on promoter methylation.Key molecules including protein kinase B(AKT),mechanistic target of rapamycin complex 1(mTORC1),and unc-51 like autophagy activating kinase 1(ULK1),as well as terminal effector molecules interleukin-1β(IL-1β),interleukin-6(IL-6),and chemokine(C-X-C motif)ligand 2(CXCL2)were selected as research targets.Wendan decoction decreased the expressions of AKT,mTORC1,IL-1β,IL-6,and CXCL2 while up-regulating ULK1 expression.Conclusion:The mechanism of Wendan decoction in preventing obesity involves the regulation of multiple signaling pathways through the control of Creb1 and Pik3cd gene promoter methylation.However,the associated multi-path gene regulation mechanism in preventing obesity is complex.Thus,further exploration is needed to elucidate the role of methylation changes in this mechanism.

Plasma DNA methylation detection for early screening,diagnosis,and monitoring of esophageal adenocarcinoma and squamous cell carcinoma

BACKGROUND The early diagnosis rate of esophageal cancer(EC),one of the most prevalent digestive tract cancers worldwide,remains low.AIM To investigate the utility of plasma SHOX2,SEPTIN9,EPO,and RNF180 methylation in the clinical diagnosis and monitoring of EC.Plasma samples were collected from 210 patients at Hubei Cancer Hospital,and TaqMan polymerase chain reaction was employed to detect plasma SHOX2,SEPTIN9,RNF180,and EPO methylation.The area under the curve was used to estimate their diagnostic value for EC.Cox and logistic regression analyses were used to estimate the independent screening risk factors for patients with EC.RESULTS The sensitivity and specificity of combined assessment of plasma SHOX2,SEPTIN9,RNF180,and EPO methylation for adenocarcinoma,squamous cell carcinoma(SCC),and EC detection were 66.67%and 86.27%,77.40%and 85.29%,and 76.19%and 86.27%,respectively;the area under the curve values for diagnosing adenocarcinoma,SCC,and EC were 0.737[95%confidence interval(CI):0.584–0.89],0.824(95%CI:0.775–0.891),and 0.864(95%CI:0.809–0.92),respectively.CONCLUSION According to our findings,plasma SHOX2,SEPTIN9,RNF180,and EPO methylation exhibits appreciated sensitivity for diagnosing EC.The precise measurement of plasma SHOX2,SEPTIN9,RNF180,and EPO methylation can improve EC diagnosis and therapy efficacy monitoring.

DNA Methylation Variation Is Identified in Monozygotic Twins Discordant for Congenital Heart Diseases

Aims:Multiple genes and environmental factors are known to be involved in congenital heart disease(CHD),but epigenetic variation has received little attention.Monozygotic(MZ)twins with CHD provide a unique model for exploring this phenomenon.In order to investigate the potential role of Deoxyribonucleic Acid(DNA)methyla-tion in CHD pathogenesis,the present study examined DNA methylation variation in MZ twins discordant for CHD,especially ventricular septal defect(VSD).Methods and Results:Using genome-wide DNA methylation profiles,we identified 4004 differentially methylated regions(DMRs)in 18 MZ twin pairs discordant for CHD,and 2826 genes were identified.Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis revealed a list of CHD-associated pathways.To further investigate the role of DNA methylation in VSD,data from 7 pairs of MZ twins with VSD were analyzed.We identified 1614 DMRs corresponding to 1443 genes associated with arrhythmogenic right ventricular cardiomyopathy,cyclic guanosine monopho-sphate-protein kinase G(cGMP-PKG)signaling pathway by KEGG analysis,and cell-cell adhesion,calcium ion transmembrane transport by GO analysis.A proportion of DMR-associated genes were involved in calcium signaling pathways.The methylation changes of calcium signaling genes might be related to VSD pathogenesis.Conclusion:CHD is associated with differential DNA methylation in MZ twins.CHD may be etiologically linked to DNA methylation,and methylation of calcium signaling genes may be involved in the development of VSD.

Methylome and transcriptome data integration reveals potential roles of DNA methylation and candidate biomarkers of cow Streptococcus uberis subclinical mastitis

Background:Mastitis caused by different pathogens including Streptococcus uberis(S.uberis)is responsible for huge economic losses to the dairy industry.In order to investigate the potential genetic and epigenetic regulatory mecha‑nisms of subclinical mastitis due to S.uberis,the DNA methylome(whole genome DNA methylation sequencing)and transcriptome(RNA sequencing)of milk somatic cells from cows with naturally occurring S.uberis subclinical mastitis and healthy control cows(n=3/group)were studied.Results:Globally,the DNA methylation levels of CpG sites were low in the promoters and first exons but high in inner exons and introns.The DNA methylation levels at the promoter,first exon and first intron regions were nega‑tively correlated with the expression level of genes at a whole‑genome‑wide scale.In general,DNA methylation level was lower in S.uberis‑positive group(SUG)than in the control group(CTG).A total of 174,342 differentially methylated cytosines(DMCs)(FDR<0.05)were identified between SUG and CTG,including 132,237,7412 and 34,693 DMCs in the context of CpG,CHG and CHH(H=A or T or C),respectively.Besides,101,612 methylation haplotype blocks(MHBs)were identified,including 451 MHBs that were significantly different(dMHB)between the two groups.A total of 2130 differentially expressed(DE)genes(1378 with up‑regulated and 752 with down‑regulated expression)were found in SUG.Integration of methylome and transcriptome data with MethGET program revealed 1623 genes with signifi‑cant changes in their methylation levels and/or gene expression changes(MetGDE genes,MethGET P‑value<0.001).Functional enrichment of genes harboring≥15 DMCs,DE genes and MetGDE genes suggest significant involvement of DNA methylation changes in the regulation of the host immune response to S.uberis infection,especially cytokine activities.Furthermore,discriminant correlation analysis with DIABLO method identified 26 candidate biomarkers,including 6 DE genes,15 CpG‑DMCs and 5 dMHBs that discriminated between SUG and CTG.Conclusion:The integration of methylome and transcriptome of milk somatic cells suggests the possible involve‑ment of DNA methylation changes in the regulation of the host immune response to subclinical mastitis due to S.uberis.The presented genetic and epigenetic biomarkers could contribute to the design of management strategies of subclinical mastitis and breeding for mastitis resistance.

Epigenetic drug library screening reveals targeting DOT1L abrogates NAD^(+)synthesis by reprogramming H3K79 methylation in uveal melanoma

Uveal melanoma(UM)is the most frequent and life-threatening ocular malignancy in adults.Aberrant histone methylation contributes to the abnormal transcriptome during oncogenesis.However,a comprehensive understanding of histone methylation patterns and their therapeutic potential in UM remains enigmatic.Herein,using a systematic epi-drug screening and a high-throughput transcriptome profiling of histone methylation modifiers,we observed that disruptor of telomeric silencing-1-like(DOT1L),a methyltransferase of histone H3 lysine 79(H3K79),was activated in UM,especially in the high-risk group.Concordantly,a systematic epi-drug library screening revealed that DOT1L inhibitors exhibited salient tumor-selective inhibitory effects on UM cells,both in vitro and in vivo.Combining Cleavage Under Targets and Tagmentation(CUT&Tag),RNA sequencing(RNA-seq),and bioinformatics analysis,we identified that DOT1L facilitated H3K79 methylation of nicotinate phosphoribosyltransferase(NAPRT)and epigenetically activated its expression.Importantly,NAPRT served as an oncogenic accelerator by enhancing nicotinamide adenine dinucleotide(NAD^(+))synthesis.Therapeutically,DOT1L inhibition epigenetically silenced NAPRT expression through the diminishment of dimethylation of H3K79(H3K79me2)in the NAPRT promoter,thereby inhibiting the malignant behaviors of UM.Conclusively,our findings delineated an integrated picture of the histone methylation landscape in UM and unveiled a novel DOT1L/NAPRT oncogenic mechanism that bridges transcriptional addiction and metabolic reprogramming.