Project description:Genome-wide patterns of DNA methylation were quantified using the Illumina Infinium EPIC array (“EPIC array”) in DNA samples isolated from buccal swabs collected at ages 5, 10 and 18 and whole blood samples collected at age 18 from 118 Monozygotic twin pairs from the Environmental Risk (E-Risk) Longitudinal Twin Study. Comparison of DNA methylation profiles of 233 age 18 blood samples with data on EPIC and Illumina 450K methylation arrays.
Project description:This study encompasses buccal sample DNA methylation (IlluminaMethylationEPIC array) from breast cancer cases and healthy age-matched controls.
Project description:Using the Infinium HM450 platform, we have performed a longitudinal study of DNA methylation at birth and age 18 months in DNA from buccal swabs from 10 monozygotic (MZ) and 5 dizygotic (DZ) twin pairs from the Peri/postnatal Epigenetic Twins Study (PETS) cohort. Beta methylation measurements from bisulphite-converted DNA and raw intensity values from 53 samples. Samples were collected at birth ('_B') or 18 months ('_18m'). Data were preprocessed using the Minfi package in R by the 'illumina' method and normalized to control probes. Subset quantile normalization was performed on type 1 and type 2 probes. Probes failing P detection cutoff of <0.01 were removed. Probes on the X and Y chromosomes have been removed from the processed data. Outlier samples were removed. Between-array quantile normalization was performed to arrive at the final data set of 330168 probes and 53 samples.
Project description:Neuroepigenetics considers genetic sequences and the interplay with environmental influences to elucidate vulnerability risk for various neurological and psychiatric disorders. However, evaluating DNA methylation of brain tissue is challenging owing to the issue of tissue specificity. Consequently, peripheral surrogate tissues were used, resulting in limited progress compared with other epigenetic studies, such as cancer research. Therefore, we developed databases to establish correlations between the brain and peripheral tissues in the same individuals. Four tissues, resected brain tissue, blood, saliva, and buccal mucosa (buccal), were collected from 19 patients (aged 13–73 years) who underwent neurosurgery. Moreover, their genome-wide DNA methylation was assessed using the Infinium HumanMethylationEPIC BeadChip arrays to determine the cross-tissue correlation of each combination. These correlation analyses were conducted with all methylation sites and with variable CpGs, and with when these were adjusted for cellular proportions. For the averaged data for each CpG across individuals, the saliva–brain correlation (r = 0.90) was higher than that for blood–brain (r = 0.87) and buccal–brain (r = 0.88) comparisons. Among individual CpGs, blood had the highest proportion of CpGs correlated to the brain at nominally significant levels (19.0%), followed by saliva (14.4%) and buccal (9.8%). These results were similar to the previous IMAGE-CpG results; however, the correlation analysis between the correlation coefficients of the datasets revealed a relatively low degree of correlation (brain vs. blood: r = 0.27, saliva; r = 0.18, and buccal; r = 0.24). To the best of our knowledge, this is the fourth study in the literature initiating the development of databases for correlations between the brain and peripheral tissues in the same individuals. We present the first database developed from an Asian population, specifically Japanese samples (AMAZE-CpG), which would contribute to interpreting individual epigenetic study results from various Asian populations.
Project description:The development of current biological markers of aging has primarily focused on adult samples. The epigenetic clock is one promising tool for measuring biological age that shows impressive accuracy across most tissues and age ranges. In adults, deviations from the DNA methylation (DNAm) age prediction are correlated with several agerelated phenotypes, such as mortality and frailty. In children, however, fewer such associations have been made, possibly because DNAm changes are more dynamic in pediatric populations as compared to adults. To address this crucial gap, we aimed to develop a highly accurate, noninvasive biological measure age specific to pediatric samples by using buccal epithelial cell DNAm. We gathered 1,721 genome-wide DNAm profiles from 11 different cohorts of typically developing individuals aged 0 to 20 y old. Elastic net penalized regression was used to select 94 CpG sites from a training dataset (n = 1,032) and the performance was assessed in a separate dataset (n = 689). The DNAm at 94 CpG sites was highly predictive of age in the test cohorts (median absolute error = 0.35 y). The Pediatric-Buccal-Epigenetic (PedBE) clock was characterized in additional cohorts, showcasing the accuracy in longitudinal data, the performance in nonbuccal tissues and adult age ranges, and the association with obstetric outcomes. The PedBE tool for measuring biological age in children might help in understanding the environmental and contextual factors that shape the DNA methylome during child development, and how it, in turn, might relate to child health and disease.
Project description:Alternations in gene methylation and other epigenetic changes regulate normal development as well as drive disease progression. Chronic cigarette smoking causes hyper- and hypo-methylation of genes that could contribute to smoking-related diseases. It is unclear whether consumers of non-combustible tobacco, such as moist snuff, also exhibit such perturbations in their methylome. Here, we present global methylation changes relative to non-tobacco consumers in buccal cells collected from smokers (SMK) and moist snuff consumers (MSC). Generally healthy adult male study subjects were recruited into SMK, MSC and Non-Tobacco Consumer (NTC) cohorts (40 subjects/cohort). Global methylation profiling was performed on the Illumina 450K methylation array using buccal cell DNA. A total of 1,252 loci were found to be significantly differentially methylated in tobacco consumers relative to non-tobacco consumers. Overall, the SMK cohort exhibited larger qualitative and quantitative changes relative to MSC. Approximately half of the total number of gene loci, classified as Combustible Tobacco-Related signatures, and a third of the changes, termed Tobacco-Related signatures, were commonly detected in the tobacco consumers. Very few differences were detected between MSC and NTC, and hierarchical clustering of the top 50 significant gene loci suggested that MSC and NTC co-cluster. Consistent with physiological functions of AhR, combustible tobacco drives profound changes in buccal cell methylation status, principally impacting cell development and immune response pathways. These results aid in placing combustible and non-combustible tobacco products along a risk continuum and provide additional insights into the effects of tobacco consumption.