Project description:DNA methylation has become increasingly recognized in the etiology of psychiatric disorders. Because brain tissue is not accessible in living humans, epigenetic studies are most often conducted in blood. Saliva is often collected for genotyping studies but is rarely used to examine DNA methylation because the proportion of epithelial cells and leukocytes varies extensively between individuals. The goal of this study was to evaluate whether saliva DNA is informative for studies of psychiatric disorders. Saliva and blood methylation was clearly distinguishable though there was positive correlation overall. There was little correlation in CpG sites within relevant candidate genes. Correlated CpG sites were more likely to occur in areas of low CpG density (i.e. CpG shores and open seas). There was more variability in CpG sites from saliva than blood, which may reflect its heterogeneity. Thus, this study provides a framework for using DNA methylation from saliva and suggests that DNA methylation of saliva may offer distinct opportunities for epidemiological and longitudinal studies of psychiatric traits. DNA methylation was assessed in saliva and blood samples from 64 adult African Americans. Both saliva and blood samples were collected from each participant. Saliva was stored in Oragene DNA sample collection kits (DNA Genotek), and blood was collected in EDTA vacuum tubes. DNA was extracted using the Puregene Genomic DNA kit (Invitrogen). DNA methylation was interrogated for each sample using the HumanMethylation450 BeadChip (Illumina). Analyses for tissue-specific DNA patterns were conducted using linear regression adjusted for appropriate covariates, including estimated cellular proportions. The estimated proportion of epithelial cells in saliva DNA ranged from 3-99% (median 26%). In blood, the estimated proportion of lymphocytes ranged from 25-70% (median 48%) and neutrophils ranged from 42-84% (median 58%). Methylation of 68.8% of all CpG sites differed relative to epithelial cell proportion (FDR<.05). Our results provide a framework for methylation studies in DNA extracted from saliva and highlight the importance of controlling for the proportion of epithelial and leukocyte cells. This presents an attractive opportunity for investigators that have already collected salivary DNA for genetic studies of psychiatric traits.
Project description:DNA methylation has become increasingly recognized in the etiology of psychiatric disorders. Because brain tissue is not accessible in living humans, epigenetic studies are most often conducted in blood. Saliva is often collected for genotyping studies but is rarely used to examine DNA methylation because the proportion of epithelial cells and leukocytes varies extensively between individuals. The goal of this study was to evaluate whether saliva DNA is informative for studies of psychiatric disorders. Saliva and blood methylation was clearly distinguishable though there was positive correlation overall. There was little correlation in CpG sites within relevant candidate genes. Correlated CpG sites were more likely to occur in areas of low CpG density (i.e. CpG shores and open seas). There was more variability in CpG sites from saliva than blood, which may reflect its heterogeneity. Thus, this study provides a framework for using DNA methylation from saliva and suggests that DNA methylation of saliva may offer distinct opportunities for epidemiological and longitudinal studies of psychiatric traits.
Project description:Folate, a water-soluble vitamin, is a key source of one-carbon groups for DNA methylation, but studies of the DNA methylation response to supplemental folic acid yield inconsistent results. The aim of this study was to determine if DNA methylation patterns in the dominant white blood cell type, neutrophils, would respond differently than whole blood in response to chronic folic acid supplementation. Saliva and blood methylation was clearly distinguishable though there was positive correlation overall. There was little correlation in CpG sites within relevant candidate genes. Correlated CpG sites were more likely to occur in areas of low CpG density (i.e. CpG shores and open seas). There was more variability in CpG sites from saliva than blood, which may reflect its heterogeneity. Thus, this study provides a framework for using DNA methylation from saliva and suggests that DNA methylation of saliva may offer distinct opportunities for epidemiological and longitudinal studies of psychiatric traits. DNA methylation was assessed in whole blood and CD16+ neutrophils from obese and normal weight adult women undergoing 8 weeks of folate supplementation. Blood was collected in EDTA vacuum tubes, and CD16+ nutrophils were isolated by positive selection with Dynabeads. DNA was extracted using the DNeasy Kit (Qiagen). DNA methylation was interrogated for each sample using the HumanMethylation450 BeadChip (Illumina).
Project description:Folate, a water-soluble vitamin, is a key source of one-carbon groups for DNA methylation, but studies of the DNA methylation response to supplemental folic acid yield inconsistent results. The aim of this study was to determine if DNA methylation patterns in the dominant white blood cell type, neutrophils, would respond differently than whole blood in response to chronic folic acid supplementation. Saliva and blood methylation was clearly distinguishable though there was positive correlation overall. There was little correlation in CpG sites within relevant candidate genes. Correlated CpG sites were more likely to occur in areas of low CpG density (i.e. CpG shores and open seas). There was more variability in CpG sites from saliva than blood, which may reflect its heterogeneity. Thus, this study provides a framework for using DNA methylation from saliva and suggests that DNA methylation of saliva may offer distinct opportunities for epidemiological and longitudinal studies of psychiatric traits.
Project description:DNA methylation from Grady Trauma Project Parental and childhood exposure to trauma increases an individual's lifetime risk for psychiatric and stress-related disorders. This study evaluates DNA methylation in saliva from children, with the goal of identifying associations between peripheral DNA methylation and psychiatric symptoms.
Project description:Gene methylation profiling of immortalized human mesenchymal stem cells comparing HPV E6/E7-transfected MSCs cells with human telomerase reverse transcriptase (hTERT)- and HPV E6/E7-transfected MSCs. hTERT may increase gene methylation in MSCs. Goal was to determine the effects of different transfected genes on global gene methylation in MSCs.
Project description:Genome wide DNA methylation profiling in paired saliva and intestinal mucosa samples from individuals undergoing gastroscopies. The Illumina Infinium 450k Human DNA methylation BeadChip was used to obtain DNA methylation profiles across approximately 485,500 CpGs. The aim of the study was to determine the utility of saliva as a surrogate for intestinal mucosa in DNA methylation studies.
Project description:We profiled the DNA methylation of saliva cell types, to develop a tool for epidemiologic studies. Saliva was collected from 22 children, 21 participants with samples usable for DNA methylation, and sorted into immune and epithelial cells, using size exclusion filtration and magnetic bead sorting. DNA methylation was measured using the Illumina MethylationEPIC BeadChip. Saliva immune and epithelial cells have distinct DNA methylation profiles, which can influence whole saliva epidemiologic measures.