Yang Jingyun, Yu Lei, Gaiteri Christopher, Srivastava Gyan P, Chibnik Lori B, Leurgans Sue E, Schneider Julie A, Meissner Alexander, De Jager Philip L, Bennett David A
Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA.
Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA.
Int J Biochem Cell Biol. 2015 Oct;67:58-64. doi: 10.1016/j.biocel.2015.05.009. Epub 2015 May 21.
DNA methylation plays a crucial role in the regulation of gene expression, cell differentiation and development. Previous studies have reported age-related alterations of methylation levels in the human brain across the lifespan, but little is known about whether the observed association with age is confounded by common neuropathologies among older persons. Using genome-wide DNA methylation data from 740 postmortem brains, we interrogated 420,132 CpG sites across the genome in a cohort of individuals with ages from 66 to 108 years old, a range of ages at which many neuropathologic indices become quite common. We compared the association of DNA methylation prior to and following adjustment for common neuropathologies using a series of linear regression models. In the simplest model adjusting for technical factors including batch effect and bisulfite conversion rate, we found 8156 CpGs associated with age. The number of CpGs associated with age dropped by more than 10% following adjustment for sex. Notably, after adjusting for common neuropathologies, the total number of CpGs associated with age was reduced by approximately 40%, compared to the sex-adjusted model. These data illustrate that the association of methylation changes in the brain with age is inflated if one does not account for age-related brain pathologies. This article is part of a Directed Issue entitled: Epigenetics dynamics in development and disease.
DNA甲基化在基因表达调控、细胞分化和发育过程中发挥着关键作用。以往研究报道了人类大脑中甲基化水平随年龄增长的变化,但对于老年人中观察到的与年龄的关联是否受到常见神经病理学的混淆影响,人们知之甚少。我们使用来自740个死后大脑的全基因组DNA甲基化数据,在一组年龄从66岁到108岁的个体中对全基因组的420,132个CpG位点进行了检测,在这个年龄段许多神经病理学指标变得相当常见。我们使用一系列线性回归模型比较了在调整常见神经病理学前后DNA甲基化与年龄的关联。在调整包括批次效应和亚硫酸氢盐转化率等技术因素的最简单模型中,我们发现8156个CpG与年龄相关。调整性别后,与年龄相关的CpG数量下降了10%以上。值得注意的是,在调整常见神经病理学后,与年龄相关的CpG总数比性别调整模型减少了约40%。这些数据表明,如果不考虑与年龄相关的脑部病变,大脑中甲基化变化与年龄的关联就会被夸大。本文是名为“发育与疾病中的表观遗传学动态”的定向专题的一部分。