ausblenden:
Schlagwörter:
epigenetic, biomarker, oragene, EWAS, Human Methylation450
Zusammenfassung:
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. DNA methylation (HumanMethylation450 BeadChip) was assessed
in saliva and blood samples from 64 adult African Americans. Analyses
were conducted using linear regression adjusted for appropriate
covariates, including estimated cellular proportions. DNA methylation
from brain tissues (cerebellum, frontal cortex, entorhinal cortex, and
superior temporal gyrus) was obtained from a publically available
dataset. 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. Finally, DNA methylation in
saliva appeared more similar to patterns from each of the brain regions
examined overall than methylation in blood. 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. (C) 2014
Wiley Periodicals, Inc.
