Reduced Representation Bisulfite Sequencing Research Articles

Intraspecific epigenomics divergence in brown bears (Ursus arctos): insights from genome-wide DNA methylation patterns

Epigenetic mechanisms such as methylation can influence gene expression and play a crucial role in the adaptation to local environmental conditions, thereby introducing non-genetic variability within species. Here, using a Reduced Representation Bisulfite Sequencing approach (RRBS), we compared the methylation patterns in blood and muscle across three European brown bear populations. Our results clearly demonstrated that, beyond tissue-driven divergences, the methylation patterns of the three populations are significantly distinct. Differentially methylated sites, possibly associated with genomic features involved in development and anatomical differentiation, are widespread across the bear genome. This finding supports previous studies suggesting a role for the alteration of developmental pathways in shaping phenotypic novelties with potential adaptative significance. Our results underscore the importance and the effectiveness of including epigenetic approaches in studying wild non-model organisms. Investigating the epigenome can be especially relevant for endangered populations that have experienced a significant erosion of genomic diversity.

Epigenome-wide association study of Chinese monozygotic twins identifies DNA methylation loci associated with estimated glomerular filtration rate

BackgroundDNA methylation (DNAm) has been shown in multiple studies to be associated with the estimated glomerular filtration rate (eGFR). However, studies focusing on Chinese populations are lacking. We conducted an epigenome-wide association study to investigate the association between DNAm and eGFR in Chinese monozygotic twins.MethodsGenome-wide DNAm level was detected using Reduced Representation Bisulfite Sequencing test. Generalized estimation equation (GEE) was used to examine the association between Cytosine-phosphate-Guanines (CpGs) DNAm and eGFR. Inference about Causation from Examination of FAmiliaL CONfounding was employed to infer the causal relationship. The comb-p was used to identify differentially methylated regions (DMRs). GeneMANIA was used to analyze the gene interaction network. The Genomic Regions Enrichment of Annotations Tool enriched biological functions and pathways. Gene expression profiling sequencing was employed to measure mRNA expression levels, and the GEE model was used to investigate the association between gene expression and eGFR. The candidate gene was validated in a community population by calculating the methylation risk score (MRS).ResultsA total of 80 CpGs and 28 DMRs, located at genes such as OLIG2, SYNGR3, LONP1, CDCP1, and SHANK1, achieved genome-wide significance level (FDR < 0.05). The causal effect of DNAm on eGFR was supported by 12 CpGs located at genes such as SYNGR3 and C9orf3. In contrast, the causal effect of eGFR on DNAm is proved by 13 CpGs located at genes such as EPHB3 and MLLT1. Enrichment analysis revealed several important biological functions and pathways related to eGFR, including alpha-2A adrenergic receptor binding pathway and corticotropin-releasing hormone receptor activity pathway. GeneMANIA results showed that SYNGR3 was co-expressed with MLLT1 and had genetic interactions with AFF4 and EDIL3. Gene expression analysis found that SYNGR3 expression was negatively associated with eGFR. Validation analysis showed that the MRS of SYNGR3 was positively associated with low eGFR levels.ConclusionsWe identified a set of CpGs, DMRs, and pathways potentially associated with eGFR, particularly in the SYNGR3 gene. These findings provided new insights into the epigenetic modifications related to the decline in eGFR and chronic kidney disease.

Acquired sperm hypomethylation by gestational arsenic exposure is re-established in both the paternal and maternal genomes of post-epigenetic reprogramming embryos

BackgroundDNA methylation plays a crucial role in mammalian development. While methylome changes acquired in the parental genomes are believed to be erased by epigenetic reprogramming, accumulating evidence suggests that methylome changes in sperm caused by environmental factors are involved in the disease phenotypes of the offspring. These findings imply that acquired sperm methylome changes are transferred to the embryo after epigenetic reprogramming. However, our understanding of this process remains incomplete. Our previous study showed that arsenic exposure of F0 pregnant mice paternally increased tumor incidence in F2 offspring. The sperm methylome of arsenic-exposed F1 males exhibited characteristic features, including enrichment of hypomethylated cytosines at the promoters of retrotransposons LINEs and LTRs. Hypomethylation of retrotransposons is potentially detrimental. Determining whether these hypomethylation changes in sperm are transferred to the embryo is important in confirming the molecular pathway of intergenerational transmission of paternal effects of arsenic exposure.ResultsWe investigated the methylome of F2 male embryos after epigenetic reprogramming by reduced representation bisulfite sequencing (RRBS) and allele-specific analysis. To do so, embryos were obtained by crossing control or gestationally arsenic-exposed F1 males (C3H/HeN strain) with control females (C57BL/6 strain). The results revealed that the methylome of F2 embryos in the arsenic group was globally hypomethylated and enriched for hypomethylated cytosines in certain genomic regions, including LTR and LINE, as observed in F1 sperm of the arsenic group. Unexpectedly, the characteristic methylome features were detected not only in the paternal genome but also in the maternal genome of embryos. Furthermore, these methylation changes were found to rarely occur at the same positions between F1 sperm and F2 embryos.ConclusionsThe results of this study revealed that the characteristics of arsenic-induced methylome changes in F1 sperm are reproduced in both the paternal and maternal genomes of post-epigenetic reprogramming embryos. Furthermore, the results suggest that this re-establishment is achieved in collaboration with other factors that mediate region-specific methylation changes. These results also highlight the possibility that arsenic-induced sperm methylome changes could contribute to the development of disease predisposition in offspring.

Peripheral Blood DNA Methylation Changes in Response to Centella asiatica Treatment in Aged Mice.

Alterations in epigenetic modifications, like DNA methylation, in peripheral blood could serve as a useful, minimally invasive biomarker of the effects of anti-aging interventions. This study explores this potential with a water extract of the botanical Centella asiatica (CAW). Eighteen-month-old mice were treated with CAW in their drinking water for 5 weeks alongside vehicle-treated eighteen-month-old C57BL6 mice. Reduced representation bisulfite sequencing (RRBS) was used to identify genome-wide differential methylation in the blood of CAW-treated aged mice compared to vehicle-treated aged mice. Our results showed a distinct enrichment of differentially methylated regions (DMRs) nearby genes involved in biological processes relevant to aging (i.e., antioxidant response, metabolic regulation, cellular metabolism). A distinct difference was observed between males and females in both the number of methylation sites and the state of methylation. Moreover, genes nearby or overlapping DMRs were found to be enriched for biological processes related to previously described cellular effects of CAW in the mouse brain (i.e., antioxidant response, metabolic regulation, calcium regulation, and circadian rhythm). Together, our data suggest that the peripheral blood methylation signature of CAW in the blood could be a useful, and readily accessible, biomarker of CAW's effects in aging.

Insights into Solea senegalensis Reproduction Through Gonadal Tissue Methylation Analysis and Transcriptomic Integration.

Fish exhibit diverse mechanisms of sex differentiation and determination, shaped by both external and internal influences, often regulated by distinct DNA methylation patterns responding to environmental changes. In S. senegalensis aquaculture, reproductive issues in captivity pose significant challenges, particularly the lack of fertilization capabilities in captive-bred males, hindering genetic improvement measures. This study analyzed the methylation patterns and transcriptomic profiles in gonadal tissue DNA from groups differing in rearing conditions and sexual maturity stages. RRBS (Reduced Representation Bisulfite Sequencing) was employed to detect notable methylation variations across groups, while RNA was extracted and sequenced for differential expression analysis. Our findings suggest that DNA methylation significantly regulates gene expression, acting as a mechanism that can both repress and enhance gene expression depending on the genomic context. The complexity of this epigenetic mechanism is evident from the varying levels of methylation and correlation rates observed in different CpGs neighboring specific genes linked to reproduction. Differential methylation comparisons revealed the highest number of differently methylated CpGs between maturation stages, followed by rearing conditions, and lastly between sexes. These findings underscore the crucial role of methylation in regulating gene expression and its potential role in sex differentiation, highlighting the complex interplay between epigenetic modifications and gene expression.

Therapy response monitoring in blood plasma from esophageal adenocarcinoma patients using cell-free DNA methylation profiling

Esophageal adenocarcinoma (EAC) is an aggressive cancer characterized by a high risk of relapse post-surgery. Current follow-up methods (serum carcinoembryonic antigen detection and PET-CT) lack sensitivity and reliability, necessitating a novel approach. Analyzing cell-free DNA (cfDNA) from blood plasma emerges as a promising avenue. This study aims to evaluate the cost-effective and genome-wide cell-free reduced representation bisulfite sequencing (cfRRBS) method combined with computational deconvolution for effective disease monitoring in EAC patients. cfDNA methylation profiling with cfRRBS was performed on 162 blood plasma samples from 33 EAC cancer patients and 28 blood plasma samples from 20 healthy donors. The estimated tumor fraction for EAC patients at the time of diagnosis was significantly different from the healthy donor plasma samples (one-sided Wilcoxon rank-sum test: p-value = 0.032). Tumor fractions above 15% and focal gains/amplifications in MYC (chr8), KRAS (chr12), EGFR (chr7) and NOTCH2 (chr1) were observed in four samples of distinct patients at the time metastatic disease was detected. This study showed feasibility to estimate tumor fractions in blood plasma of EAC patients based on cfDNA methylation using cfRRBS and computational deconvolution. Nevertheless, in this study only cancer patients with evidence of metastatic disease show high tumor fractions and copy number alterations.

High-resolution DNA methylation changes reveal biomarkers of heart failure with preserved ejection fraction versus reduced ejection fraction.

Novel biomarkers are needed to better identify-and distinguish-heart failure with preserved ejection fraction (HFpEF) from other clinical phenotypes. The goal of our study wasto identify epigenetic-sensitive biomarkers useful to a more accurate diagnosis of HFpEF. We performed a network-oriented genome-wide DNA methylation study of circulating CD4+ T lymphocytes isolated from peripheral blood using reduced representation bisulfite sequencing (RRBS) in two cohorts (i.e., discovery/validation) each of both male and female patients with HFpEF (n = 12/10), HF with reduced EF (HFrEF; n = 7/5), and volunteers lacking clinical evidence of HF (CON; n = 7/5). RRBS is the gold-standard platformfor measuring genome-wide DNA methylation changesat single-cytosine resolutionin hypothesis-generating studies. We identified three hypomethylated HFpEF-specific differentially methylated positions (DMPs) associated with FOXB1, ELMOD1, and DGKH genes wherein ROC curve analysis revealed that increased expression levels had a reasonable diagnostic performance in predicting HFpEF (AUC ≥ 0.8, p < 0.05). Network analysis identified additional three genes including JUNB (p = 0.037), SETD7 (p = 0.003), and MEF2D (p = 0.0001) which were significantly higher in HFpEF vs. HFrEFpatients. ROC curve analysis showed that integrating the functional H2FPEF classification with the expression levels of the FOXB1, ELMOD1, and DGKH as well as theJUNB, SETD7, and MEF2D genes improved diagnostic accuracy, with AUC=0.8 (p < 0.0001) as compared to H2FPEF score alone (p > 0.05). Besides, increased expression levels of SETD7-RELA-IL6 axis significantly discriminated overweight/obese HFpEF vs. HFrEF patients (AUC= 1;p = 0.001, p = 0.006, p = 0.006, respectively). We support an emerging dogma that indirect epigenetic testing via high-resolution RRBS methylomics represents a non-invasive tool that may enable easier access to both diagnostic and mechanistic insights of HFpEF. An epigenetic-oriented dysregulation of network-derived SETD7-RELA-IL6 axis in circulating CD4+ T lymphocytes may drive pro-inflammatory responses which, in turn, may lead to cardiac remodeling in overweight/obese HFpEF.

Distinct microbiome dysbiosis and epigenetic anomaly in esophageal adenocarcinoma and its underlying Barrett’s esophagus

Interaction between host genotoxic changes and mucosa-associated microbiome (MAM) dysbiosis may have a role in various digestive cancers. We investigated MAM in Barrett’s esophagus (BE) and esophageal adenocarcinoma (EAC) progression sequence and its association with host genotoxic changes. 16S rRNA gene sequencing was performed in three different groups of biopsies from nonneoplastic BE from patients without cancer (N, normal group; n = 47) and with EAC (ADJ, adjacent group; n = 27). Endoscopic biopsies were also obtained from EAC tissues (T, tumor group; n = 22). Results were correlated with TP53 mutation, telomere length and DNA methylation of candidate genes (N33, DPYS, SLC16A12, miR124A3 and miR34bc). Genome-wide DNA methylation examined by reduced representation bisulfite sequencing (RRBS) was available for 32 samples (n = 12 for N, n = 12 for ADJ and n = 22 for T groups). Lower microbial alpha diversity measures were observed in ADJ/T groups relative to N group and associated with higher mean Z score DNA methylation of candidate genes. Specific genera (n = 16) with significant change between ADJ/T groups relative to N group occurred mostly in ADJ group (13/16) and half of them (8/16) were associated with DNA methylation status. Integrated MAM and genome-wide methylation analysis demonstrated that hyper-methylated sites, associated with lower alpha diversity measures dominantly occurred within near the transcription start site, codifying genes were involved in metabolic processes. Our result shows that microbial dysbiosis in EAC mostly occurs in adjacent BE and such dysbiosis was associated with DNA methylation status, offering support for a pathogenic role of interaction between host genotoxic changes and MAM in this tumor type.

Epigenetic and Cellular Reprogramming of Doxorubicin-Resistant MCF-7 Cells Treated with Curcumin.

The MCF-7R breast cancer cell line, developed by treating the parental MCF-7 cells with increasing doses of doxorubicin, serves as a model for studying acquired multidrug resistance (MDR). MDR is a major challenge in cancer therapy, often driven by overexpression of the efflux pump P-glycoprotein (P-gp) and epigenetic modifications. While many P-gp inhibitors show promise in vitro, their nonspecific effects on the efflux pump limit in vivo application. Curcumin, a natural compound with pleiotropic action, is a nontoxic P-gp inhibitor capable of modulating multiple pathways. To explore curcumin's molecular effects on MCF-7R cells, we analyzed the expression of genes involved in DNA methylation and transcription regulation, including ABCB1/MDR1. Reduced representation bisulfite sequencing further unveiled key epigenetic changes induced by curcumin. Our findings indicate that curcumin treatment not only modulates critical cellular processes, such as ribosome biogenesis and cytoskeletal dynamics, but also reverses the resistant phenotype, toward that of sensitive cells. This study highlights curcumin's potential as an adjuvant therapy to overcome chemoresistance, offering new avenues for pharmacological strategies targeting epigenetic regulation to re-sensitize resistant cancer cells.

DNA Imprinting and Differentially Expressed Genes in Longissimus thoracis Muscle of Bos indicus Submitted to Early Weaning Management.

Background/Objectives: Early weaning management followed by energy supplementation can lead to metabolic alterations in the calf that exert long-term effects on the animal's health and performance. It is believed that the main molecular basis underlying these metabolic adaptations are epigenetic mechanisms that regulate, activate, or silence genes at different stages of development and/or in response to different environmental stimuli. However, little is known about postnatal metabolic programming in Bos indicus. Therefore, this study aimed to compare the DNA methylation profile of Nellore animals submitted to conventional and early weaning and to correlate the findings with genes differentially expressed in the Longissimus thoracis skeletal muscle of Bos indicus cattle. Methods: For this, we used Reduced Representation Bisulfite Sequencing (RRBS) and RNA-Sequencing techniques to prospect differentially methylated genes (DMGs). Results: A total of 481 differentially methylated regions were identified, with 52% (250) being hypermethylated and 48% (231) hypomethylated. Functional enrichment analysis of 53 differentially methylated and differentially expressed genes was performed. The main enriched terms and pathways were associated with 3'-5'-cyclic adenosine monophosphate (cAMP) signaling, which presents the upregulated adenylate cyclase 3 (ADCY3) gene and significatively hypomethylated in the promoter region. Alterations in cAMP signaling are involved in numerous processes, many of them related to lipid metabolism. The relative differential expression of key genes of this pathway demonstrates the relationship between cAMP signaling and de novo lipogenesis. Conclusions: These findings suggest an important role of postnatal metabolic programming through DNA methylation mechanisms in determining fat deposition in beef.

DNA methylation profiling of CpG islands in trigeminal ganglion of rats with orofacial pain induced by experimental tooth movement

BackgroundTooth movement induced orofacial pain is the most cited negative effect during orthodontic treatment, while treatment options without side effects are limited. The differential expression of pain-related genes due to DNA methylation and demethylation is instrumental in pain. The purpose of the study was to evaluate the DNA methylation profiling of CpG islands (CGI) and CGI shores in promoter regions in trigeminal ganglions (TG) of tooth movement induced orofacial pain rats, thus to further insight the DNA methylation regulation in orofacial pain.Materials and methodsAn orofacial pain rat model was constructed by ligating coil springs between the incisor and first maxillary molar with 40 g of force. The Rat Grimace Score (RGS) was used for pain evaluation. The genome methylation status was analyzed by the reduced representation bisulfite sequencing (RRBS) technique. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analyses were conducted in the differentially methylated regions (DMRs). Moreover, a protein-protein interaction (PPI) network was established to detect annotated genes associated with pain.ResultsRGS was significantly higher in orofacial pain rats than in sham rats. RRBS showed widespread methylation changes in CGI and CGI shores in TG promoter regions. Both 902 hypermethylated DMRs and 862 hypomethylated DMRs were found in the CGIs of promoter regions. KEGG analysis revealed that annotated genes are participated in endocrine, nervous, immune, and sensory systems. Moreover, the “Calcium signaling pathway”, “Wnt signaling pathway” and “Neuroactive ligand-receptor interaction” were significantly enriched pathways. Furthermore, PPI network showed several genes (Ctnnb1, Dlg4, Creb1, Camk2g, Bmp2, etc.) with different methylation statuses were reported to be associated with pain.ConclusionsThis study demonstrated methylation changes were existed in CGI and CGI shores in TG promoter regions when pain occurs, thus providing a basis for further study on the mechanism of DNA methylation in orofacial pain.

Genetic Architecture of Immune Cell DNA Methylation in the Rhesus Macaque.

Genetic variation that impacts gene regulation, rather than protein function, can have strong effects on trait variation both within and between species. Epigenetic mechanisms, such as DNA methylation, are often an important intermediate link between genotype and phenotype, yet genetic effects on DNA methylation remain understudied in natural populations. To address this gap, we used reduced representation bisulfite sequencing to measure DNA methylation levels at 555,856 CpGs in peripheral whole blood of 573 samples collected from free-ranging rhesus macaques (Macaca mulatta) living on the island of Cayo Santiago, Puerto Rico. We used allele-specific methods to map cis-methylation quantitative trait loci (meQTL) and tested for effects of 243,389 single nucleotide polymorphisms (SNPs) on local DNA methylation levels. Of 776,092 tested SNP-CpG pairs, we identified 516,213 meQTL, with 69.12% of CpGs having at least one meQTL (FDR < 5%). On average, meQTL explained 21.2% of nearby methylation variance, significantly more than age or sex. meQTL were enriched in genomic compartments where methylation is likely to impact gene expression, for example, promoters, enhancers and binding sites for methylation-sensitive transcription factors. In support, using mRNA-seq data from 172 samples, we confirmed 332 meQTL as whole blood cis-expression QTL (eQTL) in the population, and found meQTL-eQTL genes were enriched for immune response functions, like antigen presentation and inflammation. Overall, our study takes an important step towards understanding the genetic architecture of DNA methylation in natural populations, and more generally points to the biological mechanisms driving phenotypic variation in our close relatives.

Blood Plasma Methylated DNA Markers in the Detection of Lymphoma: Discovery, Validation, and Clinical Pilot.

Lymphoma is one of the leading causes of cancer and cancer deaths and yet has not been amenable to population screening. The role of methylated DNA markers (MDMs) in the detection of lymphoma has not been extensively studied. We aimed to discover, validate, and test tissue-derived MDMs of lymphoma in archival plasma specimens. Reduced representation bisulfite sequencing (RRBS) was performed on a discovery set of frozen tissues. MDMs identified were converted to methylation-specific PCR assays and validated on independent formalin-fixed, paraffin-embedded (FFPE) tissues. Target enrichment long-probe quantitative-amplified signal (TELQAS) assays were developed and assayed in plasma-extracted, bisulfite-converted DNA from independent treatment-naïve lymphoma patients and healthy controls. Prediction of cancer status was modeled using random forest model with in silico cross-validation. After discovery and validation in tissue, 16 TELQAS assays (ZNF503, VWA5B1, HOXA9, GABRG3, ITGA5, MAX.chr17.7190, BNC1, CDK20, MAX.chr4.4069, TPBG, DNAH14, SYT6, CACNG8, FAM110B, ADRA1D, and NRN1) were selected for testing in plasma. These detected 78% (95% CI, 74%-82%) of lymphoma cases at 90% specificity. Excluding marginal zone and T-cell lymphomas, sensitivity increased to 84% (80%-88%). MDMs in plasma show promise to detect lymphoma and are candidates for inclusion in multi-cancer detection studies.

Epigenetic modulation of NLRP6 inflammasome sensor as a therapeutic modality to reduce necroptosis-driven gastrointestinal mucosal dysfunction in HIV/SIV infection.

The epigenetic mechanisms driving persistent gastrointestinal mucosal dysfunction in HIV/SIV infection is an understudied topic. Using reduced-representation bisulfite sequencing, we identified HIV/SIV infection in combination anti-retroviral therapy (cART)-naive rhesus macaques (RMs) to induce marked hypomethylation throughout promoter-associated CpG islands (paCGIs) in genes related to inflammatory response ( NLRP6, cGAS ), cellular adhesion and proliferation in colonic epithelial cells (CEs). Moreover, low-dose delta-9-tetrahydrocannabinol (THC) administration reduced NLRP6 protein expression in CE by hypermethylating the NLRP6 paCGI and blocked polyI:C induced NLRP6 upregulation in vitro. In cART suppressed SIV-infected RMs, NLRP6 protein upregulation associated with significantly increased expression of necroptosis-driving proteins; phosphorylated-RIPK3(Ser199), phosphorylated-MLKL(Thr357/Ser358), and HMGB1. Most strikingly, supplementing cART with THC effectively reduced NLRP6 and necroptosis-driving protein expression to pre-infection levels. These findings for the first time demonstrate that NLRP6 upregulation and ensuing activation of necroptosis promote HIV/SIV-induced gastrointestinal mucosal dysfunction and that epigenetic modulation using phytocannabinoids represents a feasible therapeutic modality for alleviating HIV/SIV-induced gastrointestinal inflammation and associated comorbidities.

Dna methylation profile in comorbidity of aneurysm and atherosclerosis of the ascending aorta

This study presents the results of DNA methylation analysis in different regions of the ascending aorta (dilated, non-dilated area, atherosclerotic plaque) in patients with aortic aneurysm. DNA methylation was analyzed by reduced representation bisulfite sequencing (RRBS). Differences in methylation levels between dilated and normal aortic tissues were detected for two CpG sites of the NR2F1-AS1 gene (|Δβ| ≥ 0.2 and FDR 0.05). Between atherosclerotic plaque samples and dilated/normal aortic tissues, 586/480 differentially methylated CpG sites (DMSs) were identified, among which 323/234 were hypermethylated and 263/246 were hypomethylated in atherosclerotic plaques. DMSs were located mainly in introns and intergenic regions, 88.2% in the binding sites of TFs, among which ZNf263, ZFP148, PATZ1, NRF1, TCF12, EGR1 play a role in the pathogenesis of atherosclerosis of various arteries, and ELK1, ETS1, KLF15 play a role in aortic aneurysms. Sixteen DMSs are located in the region of genes (CMIP, RPH3AL, XRCC1, GATA5, EXD3, KCNC2, HIVEP3, ADCY9, CDCP2, FOLR1, WT1, MGMT, GAS2, CA1, PRSS16, ANK3) whose protein products are involved in the development of both aortic dissection and atherosclerosis in different arterial circulation regions. The protein products of these genes are involved in a wide range of biological processes, including mesenchyme development (GO:0060485, FOLR1, WT1, GATA5, HIVEP3, KCNC2) and positive regulation of DNA metabolic process (GO:0051054, MGMT, WT1, XRCC1).

Abstract 4124828: The Methylation Landscape Of Human Aortic And Mitral Valvular Interstitial Cells

Valvular interstitial cells (VICs), the valves’ predominant cell type, are crucial in ensuring proper valve function, structural integrity, tissue repair and valve homeostasis. DNA methylation regulates gene expression profiles and a matched aortic to mitral human VIC methylation analysis will further our understanding of aortic- and mitral-specific VIC biology and pathobiology. This is the first study analyzing methylation profiles of non-diseased, matched human aortic and mitral VICs. We analyzed the differential methylation fingerprint of 12 non-diseased aortic and mitral VICs (10 males:2 females; 42–64 years) extracted from de-endothelialized leaflets using reduced representation bisulfite sequencing (RRBS) on HiSeq2500. Analysis of methylation levels of 12,676 genome-wide promoters revealed 651 differentially methylated (DM) promoters. The top 3 DM promoters were linked to TBX4 (meth diff = -28.9%, P = 5.2E-135) essential for valve morphogenesis, to EXOC3L2 (meth diff = 25.7%, P = 1.3E-92) and NT5DC2 (meth diff = -20.3%, P = 7.1E-69) potentially implicated in ECM remodeling, the former via vesicle trafficking and the latter through nucleotide metabolism. Functional classification and network analysis showed that the genes associated with the DM promoters were enriched for WNT-, TGFβ-, FGF-, EGF- and PDGF- pathways involved in physiological processes such as valve development, repair and VIC regulation, as well as pathological processes such as calcification. Additional enrichment was detected for integrin- and cadherin- pathways involved in cell-cell-ECM interactions and endothelin- and VEGF pathways involved in hemodynamic regulation. This work provides the first insight into the differential methylation regulation patterns of human aortic and mitral VICs. Understanding how aortic and mitral VICs are differentially epigenetically regulated will extend our understanding of their role in aortic- and mitral-specific leaflet homeostasis, susceptibility to disease processes and will contribute to dynamic innovative experimental setup designs, animal-free human-based modeling frameworks, tissue engineering and drug identification approaches.

Abstract 4141496: Methylation changes in monocytes of type 2 diabetes patients with cardiovascular disease are associated with apoptosis and inflammation pathways.

Background: Monocytes have been implicated in the initiation and progression of cardiovascular (CV) complications of type 2 diabetes (T2D). Aim: We investigated diabetes-induced methylation changes and enriched pathways in circulating monocytes of T2D patients. We compared T2D vs. non-T2D participants and analyzed T2D patients according to diabetes control. Further, we assessed methylation changes in a subset of patients with poor diabetes control and high CV risk following a 6-month treatment intensification. Methods: We recruited consecutively 200 participants, 160 with T2D and 40 non-diabetes controls. Circulating monocytes were sorted using the FACSAria2 ™ cell sorter. Samples were sequenced using enhanced reduced representation bisulfite sequencing. Methylation data was processed with Lumi and limma R packages to obtain batch and covariate corrected differential expression values for the indicated comparisons. Ingenuity Pathway Analysis (Qiagen) was used to identify enriched pathways for each tested condition. Differentially methylated genes used for pathway analysis were those with a p-value &lt; 0.05 and an absolute logFC value ≥ 0.5. Results: There were 1122 differentially methylated genes when comparing T2D to non-T2D patients. Among the top five enriched canonical pathways, apoptosis signaling was predicted to be activated, while the RHO GTPase cycle and LPS-stimulated MAPK signaling pathways were predicted to be inhibited. Within patients with diabetes, there were 1670 differentially methylated genes comparing those with poor control (HbA1c ≥ 7%) vs. good control (HbA1c&lt;7%). Among the top five enriched pathways, synthesis of DNA, DNA replication signaling, and cell cycle checkpoints were activated while inhibition of ARE-mediated mRNA degradation pathway was inhibited. In patients who responded to treatment intensification (Δ HbA1c = -1.5%, p= 0.02), 1377 differentially methylated genes and differentially inhibited pathways such as non-homologous end-joining and cellular response to heat stress were identified. In non-responders, we identified 1582 differentially methylated genes and activated pathways, including inhibition of mRNA degradation pathways and p14/p19 ARF signaling. Conclusion: Treatment intensification in T2D patients with CVD and poor control showed the presence of differentially methylated genes affecting pathways regulating cell proliferation and inflammation and are known to be associated with diabetic CVD complications.

Blood and Bone-Derived DNA Methylation Ages Predict Mortality After Geriatric Hip Fracture: A Pilot Study.

The purpose of this study was to (1) perform the first analysis of bone-derived DNA methylation, (2) compare DNA methylation clocks derived from bone with those derived from whole blood, and (3) establish a relationship between DNA methylation age and 1-year mortality within the geriatric hip fracture population. Patients ≥65 years old who presented to a Level-I trauma center with a hip fracture were prospectively enrolled from 2020 to 2021. Preoperative whole blood and intraoperative bone samples were collected. Following DNA extraction, RRBS (reduced representation bisulfite sequencing) libraries for methylation clock analysis were prepared. Sequencing data were analyzed using computational algorithms previously described by Horvath et al. to build a regression model of methylation (biological) age for each tissue type. Student t tests were used to analyze differences (Δ) in methylation age versus chronological age. Correlation between blood and bone methylation ages was expressed using the Pearson R coefficient. Blood and bone samples were collected from 47 patients. DNA extraction, sequencing, and methylation analysis were performed on 24 specimens from 12 subjects. Mean age at presentation was 85.4 ± 8.65 years. There was no difference in DNA extraction yield between the blood and bone samples (p = 0.935). The mean follow-up duration was 12.4 ± 4.3 months. The mortality cohort (4 patients, 33%) showed a mean ΔAgeBone of 18.33 ± 6.47 years and mean ΔAgeBlood of 16.93 ± 4.02 years. In comparison, the survival cohort showed a significantly lower mean ΔAgeBone and ΔAgeBlood (7.86 ± 6.7 and 7.31 ± 7.71 years; p = 0.026 and 0.039, respectively). Bone-derived methylation age was strongly correlated with blood-derived methylation age (R = 0.81; p = 0.0016). Bone-derived DNA methylation clocks were found to be both feasible and strongly correlated with those derived from whole blood within a geriatric hip fracture population. Mortality was independently associated with the DNA methylation age, and that age was approximately 17 years greater than chronological age in the mortality cohort. The results of the present study suggest that prevention of advanced DNA methylation may play a key role in decreasing mortality following hip fracture. Prognostic Level I. See Instructions for Authors for a complete description of levels of evidence.

Identification of a DNA methylation signature in whole blood of newborn guinea pigs and human neonates following antenatal betamethasone exposure

Antenatal corticosteroids (ACS) are administered where there is risk of preterm birth to promote fetal lung development and improve perinatal survival. However, treatment may be associated with increased risk of developing neurobehavioural disorders. We have recently identified that ACS results in significant changes to DNA methylation patterns in the newborn and juvenile prefrontal cortex (PFC) of exposed guinea pig offspring. Methylation changes at transcription factor binding sites (TFBS) for PLAGL1, TFAP2C, ZNF263, and SP1 were consistently noted at both post-natal stages, suggesting a long-lasting signature of ACS exposure. In this study, we determined if comparable methylation changes are also present in the newborn blood of ACS-exposed guinea pig offspring, as this would determine whether blood methylation patterns may be used as a peripheral biomarker of changes in the brain. Pregnant guinea pigs were treated with saline or betamethasone (1 mg/kg) on gestational days 50/51. gDNA from whole blood of term-born offspring on post-natal day (PND) 1 was used for reduced representation bisulfite sequencing. Overall, 1677 differentially methylated CpG sites (DMCs) were identified in response to ACS. While no specific DMCs identified in the blood overlapped with those previously reported in the PFC of PND1 offspring, significant differential methylation at TFBSs for PLAGL1, TFAP2C, EGR1, ZNF263, and SP1 was persistently observed. Furthermore, re-examination of our previously reported data of DMCs in human neonatal blood following ACS identified the presence of this same TFBS signature in human infants, suggesting the potential for clinical translation of our epigenomic data.

Epigenetic insights into creep-feeding: methylation profiling of Longissimus thoracis muscle at weaning in crossbred cattle

IntroductionThis study investigated the impact of creep-feeding supplementation on the genome methylation of the Longissimus thoracis (LT) muscle in crossbred beef cattle (Bos taurus × Bos indicus).MethodsThe experiment involved 48 uncastrated F1 Angus-Nellore males (half-siblings), which were divided into two groups: NCF – no creep-feeding (n = 24) and CF – creep-feeding (n = 24). After weaning at 210 days, all animals were feedlot finished for 180 days under identical conditions. LT muscle biopsies were collected at weaning for genomic DNA methylation analysis by reduced representation bisulfite sequencing (RRBS).Results and discussionThe groups differed significantly (CF &amp;gt; NCF: p &amp;lt; 0.05) to weaning weight (243.57±5.70 vs. 228.92±5.07kg), backfat thickness (12.96±0.86 vs. 10.61±0.42mm), LT muscle marbling score (366.11±12.39 vs. 321.50±13.65), and LT intramuscular fat content (5.80±0.23 vs. 4.95±0.20%). The weights at the beginning of the experiment and at slaughter (390 days) did not differ significantly. Mean methylation levels were higher in CF with 0.18% more CpG, 0.04% CHG, and 0.03% CHH. We identified 974 regions with differential methylation (DMRs: &amp;gt; 25% and q &amp;lt; 0.05), which overlapped with 241 differentially methylated genes (DMGs). Among these genes, 108 were hypermethylated and 133 were hypomethylated in CF group. Notably, 39 of these DMGs were previously identified as differentially expressed genes (DEGs: log2 fold change [0.5]) in the same animal groups. Over-representation analysis highlighted epigenetic regulations related to muscle growth, PPAR signaling, adipogenesis, insulin response, and lipid metabolism. Key DMGs/DEGs included: ACAA1, SORBS1, SMAD3, TRIM63, PRKCA, DNMT3A, RUNX1, NRG3, and SLC2A8. These epigenetic changes improved the performance of supplemented animals up to weaning and enhanced meat quality traits, particularly higher intramuscular fat. The results provided insights into the intricate interplay between nutrition, epigenetics, gene expression and phenotypes in beef cattle production.