Project description:Chronic pain is a global public health problem, but the underlying molecular mechanisms are not fully understood. Here we examine genome-wide DNA methylation, first in 50 identical twins discordant for heat pain sensitivity and then in 50 further unrelated individuals. Whole blood DNA methylation was characterized at 5.2 million loci by MeDIP-sequencing and assessed longitudinally to identify differentially methylated regions associated with high or low pain-sensitivity (pain-DMRs). Nine meta-analysis pain-DMRs show robust evidence for association (false discovery rate 5%) with the strongest signal in the pain gene TRPA1 (P=1.2M-CM-^W10-13). Several pain-DMRs show longitudinal stability consistent with susceptibility effects, have similar methylation levels in brain, and altered expression in skin. Our approach identifies epigenetic changes in both novel and established candidate genes that provide molecular insights into pain and may generalize to other complex traits. MeDIP-sequencing in 100 individulas using a 2 stage design: paired-end MeDIP-seq in 50 monozygotic twins and single-end MeDIP-seq in 50 unrelated individuals.
Project description:Atherosclerosis preferentially develops in arterial regions where hemodynamic disturbed flow and oxidative stress are present. Epigenomic regulation, especially DNA methylation, plays an essential role in regulating gene expression in response to environmental factors. We investigated the DNA methylation of endothelial cells isolated from distinctly different hemodynamic and oxidative stress environments in normal adult domestic swine: an athero-susceptible site located at the inner curvature of the aortic arch (AA) and an athero-protected region in the descending thoracic aorta (DT). Genome-wide DNA methylation landscapes as well as differential methylation regions (DMRs) were generated by methylated DNA immunoprecipitation sequencing (MeDIP-seq).
Project description:Interactions between the nuclear lamina (NL) and chromatin are thought to occur through large lamin association domains (LADs) and correlate with gene repression in these domains. We show that binding of lamin A/C (LMNA) to promoters occurs on discrete domains that are associated with distinct transcriptional outputs. Chromatin immunoprecipitation identifies thousands of LMNA-bound promoters, primarily linked to signaling functions. LMNA often occupies narrow domains on promoters, yet LMNA-bound promoters are often contiguous. LMNA-bound genes are overall repressed, but repression correlates with co-enrichment in repressive histone marks rather than LMNA occupancy per se. Genes marked by LMNA and H3K4me3 escape LMNA-associated repression in the absence of repressive histone marks. Positioning of LMNA on promoters relative to the TSS correlates with distinct transcriptional outputs: whereas upstream-distal binding can be transcriptionally permissive, TSS occupancy is associated with promoter inactivity. Perturbation in NL organization causes reorganization of lamin promoter occupancy and uncouples LMNA binding from promoter inactivity. Our results show the existence of many spatially restricted LMNA binding events on promoter regions, with distinct position-dependent transcriptional outputs. ChIPs were done from cultured untreated and LMNA-downregulated adipose stem cell (ASC) chromatin. MeDIPs were done from LMNA-downregulated ASCs. ChIP and MeDIP DNA was hybridized onto the aforementioned HG-18 Nimbegen promoter arrays.
Project description:Evidence suggests that epigenetic perturbations are involved in the adverse effects associated with some drugs and toxicants, including certain classes of non-genotoxic carcinogens. Such epigenetic changes (altered DNA methylation and covalent histone modifications) may take place at the earliest stages of carcinogenesis and their identification holds great promise for biomedical research. Here, we evaluate the sensitivity and specificity of genome-wide epigenomic and transcriptomic profiling in phenobarbital (PB)-treated B6C3F1 mice, a well-characterized rodent model of non-genotoxic liver carcinogenesis. Methylated DNA Immunoprecipitation (MeDIP)-coupled microarray profiling of 17,967 promoter regions and 4,566 intergenic CpG islands was combined with genome-wide mRNA expression profiling to identify liver tissue-specific PB-mediated DNA methylation and transcriptional alterations. Only a limited number of significant anti-correlations were observed between PB-induced transcriptional and promoter-based DNA methylation perturbations. However, the constitutive androstane receptor (CAR) target gene Cyp2b10 was found to be concomitantly hypomethylated and transcriptionally activated in a liver tissue-specific manner following PB treatment. Furthermore, analysis of active and repressive histone modifications using chromatin immunoprecipitation revealed a strong PB-mediated epigenetic switch at the Cyp2b10 promoter. Our data reveal that PB-induced transcriptional perturbations are not generally associated with broad changes in the DNA methylation status at proximal promoters and suggest that the drug-inducible CAR pathway regulates an epigenetic switch from repressive to active chromatin at the target gene Cyp2b10. This study demonstrates the utility of integrated epigenomic and transcriptomic profiling for elucidating early mechanisms and biomarkers of non-genotoxic carcinogenesis. 29M-bM-^@M-^S32 days old male B6C3F1/Crl (C57BL/6 M-bM-^YM-^B x C3H/He M-bM-^YM-^@) mice were obtained from Charles River Laboratories (Germany). Animals were allowed to acclimatise for 5 days prior to being randomly divided into two treatment groups (n = 10) and phenobarbital (Sigma 04710, 0.05% (w/v) in drinking water) was administered to one group through ad libitum access to drinking water for 28 days. Mice were checked daily for activity and behavior and sacrificed on the last day of dosing (day 28). Blood was withdrawn for PK analysis and target (liver) and non-target (kidney) tissues removed, split into several sections, frozen in liquid nitrogen and stored at M-bM-^HM-^R80M-BM-0C for subsequent analyses. Total RNA from liver and kidney was purified and processed for Affymetrix gene expression profiling while genomic DNA was prepared for promoter array based methylome analysis using the Methylated DNA immunoprecipitation (MeDIP) procedure. Remaining tissue material was used for chromatin immunoprecipitation (ChIP) to analyze histone modifications at individual promoters. Plasma samples were also collected to evaluate phenobarbital exposure in individual animals by LC-MS.
Project description:Aberrant CpG methylation is a universal trait of cancer cell genomes and can result in epigenetic modulation of gene activity; however, at which stages tumour-specific epigenetic patterns arise is unknown. Here, we analyse the methylome of APCM in mouse intestinal adenoma as a model of intestinal cancer initiation, and inventory a map of over 13,000 adenoma-specific recurrent differentially methylated regions (DMRs). We find that multiple genes coding for Polycomb proteins are upregulated in adenoma, and concomitantly, hypermethylated DMRs form preferentially at Polycomb target sites. We establish that DMRs are absent from proliferating intestinal epithelial cells or intestinal stem cells, and thus arise de novo after loss of APC. Importantly, a core set of DMRs is conserved in human colon cancer, defining a class of early epigenetic alterations that are distinct from known sets of epigenetically silenced tumour suppressors. The data presented suggests a sequence of events that leads to an altered methylome of colon cancer cells, and may allow more specific selection of clinical epigenetic biomarkers. Analysis of the methylome and RNA expression in adenoma of Apc-Min/+ mutant mice and of normal intestine in Apc-Min/+ and Apc-+/+ wild type mice.
Project description:Abstract Scope: The âPredictive Adaptive Responseâ hypothesis suggests the in utero environment when mismatched with the post-natal environment can influence later life health. Underlying mechanisms are poorly understood, but may involve gene transcription changes, regulated via epigenetic mechanisms. Methods and Results: In a 2x2 factorial design, female C57Bl/6 mice were randomised to low or normal folate diets (0.4mg/2mg folic acid/kg diet) prior to and during pregnancy and lactation with, offspring randomised to high or low fat diets at weaning. Genome-wide gene expression and promoter DNA methylation were measured using microarrays in adult male livers. Maternal folate depletion and high fat intake post-weaning influenced gene expression (1959 and 1612 genes respectively) and promoter DNA methylation (208 and 344 loci respectively) but changes in expression and methylation were poorly matched for both dietary interventions. Expression of 667 genes was altered in response to both maternal folate depletion and post-weaning high fat feeding. In addition, there was evidence that the combined dietary insult (i.e. maternal folate depletion followed by high fat post-weaning) exerted the largest expression change for most of these genes. Conclusion: Our observations align with, and provide evidence in support of a potential underlying mechanism for, the âPredictive Adaptive Responseâ hypothesis. Elucidation of these mechanisms may identify targets for interventions to mitigate effects of adverse nutrition exposures during early development on disease risk in later life.
Project description:The actions of environmental toxicants and relevant mixtures in promoting the epigenetic transgenerational inheritance of ovarian disease was investigated with the use of a fungicide, a pesticide mixture, a plastic mixture, dioxin and a hydrocarbon mixture. After transient exposure of an F0 gestating female rat during embryonic gonadal sex determination, the F1 and F3 generation progeny adult onset ovarian disease was assessed. Transgenerational disease phenotypes observed included an increase in cysts resembling human polycystic ovarian disease (PCO) and a decrease in the ovarian primordial follicle pool size resembling primary ovarian insufficiency (POI). The F3 generation granulosa cells were isolated and found to have a transgenerational effect on the transcriptome and epigenome (differential DNA methylation). Epigenetic biomarkers for environmental exposure and associated gene networks were identified. Epigenetic transgenerational inheritance of ovarian disease states was induced by all the different classes of environmental compounds, suggesting a role of environmental epigenetics in ovarian disease etiology. Granulosa cells from large antral follicles were collected and evaluated from F3 generation rats that were ancestrally exposed to one of the five different treatments: Vinclozolin, Pesticide (includes permethrin and DEET), Plastics (includes BPA, DBP and DEHP), Low-dose Plastics (50% of Plastics dose), Dioxin, Hydrocarbon (Jet fuel JP8), or DMSO vehicle as Control. Vinclozolin lineage alterations in differentially DNA methylated regions (DMR) in the granulosa cells was investigated by using a methylated DNA immunoprecipitation (MeDIP) procedure followed by comparative hybridization on a genome wide promoter tiling array (Chip), termed an MeDIP-Chip assay. The DNA fractions from four animals of the same treatment group were pooled to create three different pooled DNA samples from each of the two treatment groups (experimental vs. control). These DNA samples were then used for methylated DNA immunoprecipitation (MeDIP) using Nimblegen microarrays. Each MeDIP sample was then used to preform three different comparative (amplified MeDIP vs. amplified MeDIP) hybridization experiments (3 sub-arrays), each encompassing DNA samples from 24 animls (3 treatment and 3 control groups).
Project description:Background: Age-related physiological, biochemical and functional changes in mammalian skeletal muscle have been shown to begin at the mid-point of the lifespan. However, the underlying changes in DNA methylation that occur during this turning point of the muscle aging process have not been clarified. To explore age-related genomic methylation changes in skeletal muscle, we employed young (0.5 years old) and middle-aged (7 years old) pigs as models to survey genome-wide DNA methylation in the longissimus dorsi muscle using a methylated DNA immunoprecipitation sequencing approach. Results: We observed a tendency toward a global loss of DNA methylation in the gene-body region of the skeletal muscle of the middle-aged pigs compared with the young group. We determined the genome-wide gene expression pattern in the longissimus dorsi muscle using microarray analysis and performed a correlation analysis using DMR (differentially methylated region)-mRNA pairs, and we found a significant negative correlation between the changes in methylation levels within gene bodies and gene expression. Furthermore, we identified numerous genes that show age-related methylation changes that are potentially involved in the aging process. The methylation status of these genes was confirmed using bisulfite sequencing PCR. The genes that exhibited a hypomethylated gene body in middle-aged pigs were over-represented in various proteolysis and protein catabolic processes, suggesting an important role for these genes in age-related muscle atrophy. In addition, genes associated with tumorigenesis exhibited aged-related differences in methylation and expression levels, suggesting an increased risk of disease associated with increased age. Conclusions: This study provides a comprehensive analysis of genome-wide DNA methylation patterns in aging pig skeletal muscle. Our findings will serve as a valuable resource in aging studies, promoting the pig as a model organism for human aging research and accelerating the development of comparative animal models in aging research. We collected the longissimus dorsi muscles tissue from Jinhua pigs which aged 0.5 year and seven years and study the genome-wide DNA methylation difference between the two age periods.
Project description:The canine transmissible veneral tumour (CTVT) is one of the few known clonally transmissible cancers in nature. CTVT regresses spontaneously or after a single treatment with vincristine, however we know little of the mechanisms. To understand CTVT regression, we performed methylome analyses on serial biopsies of regressing and non-regressing CTVT, aiming to identify the likely drivers of CTVT regression.