The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, and Chongqing Eye Institute, Chongqing.
Shanghai Biotechnology Corporation, Shanghai, China and.
Rheumatology (Oxford). 2019 Sep 1;58(9):1574-1584. doi: 10.1093/rheumatology/kez043.
The aetiology of Behçet's disease (BD), known as a systemic vasculitis, is not completely understood. Increasing evidence suggests that aberrant DNA methylation may contribute to the pathogenesis of BD. The aim of this epigenome-wide association study was to identify BD-associated methylation loci in Han Chinese.
Genome-wide DNA methylation profiles were compared between 60 BD patients and 60 healthy controls using the Infinium Human Methylation 450 K Beadchip. BD-associated methylation loci were validated in 100 BD patients and 100 healthy controls by pyrosequencing. Gene expression and cytokine production was quantified by real-time PCR and ELISA.
A total of 4332 differentially methylated CpG sites were associated with BD. Five differentially methylated CpG sites (cg03546163, cg25114611, cg20228731, cg23261343 and cg14290576) revealed a significant hypomethylation status across four different genes (FKBP5, FLJ43663, RUNX2 and NFIL3) and were validated by pyrosequencing. Validation results showed that the most significant locus was located in the 5'UTR of FKBP5 (cg03546163, P = 3.81E-13). Four CpG sites with an aberrant methylation status, including cg03546163, cg25114611, cg23261343 and cg14290576, may serve as a diagnostic marker for BD (area under the receiver operating curve curve = 83.95%, 95% CI 78.20, 89.70%). A significantly inverse correlation was found between the degree of methylation at cg03546163 as well as cg25114611 and FKBP5 mRNA expression. Treatment with a demethylation agent, 5-Aza-2'-deoxycytidine resulted in an increase of FKBP5 mRNA expression and a stimulated IL-1β production.
Our findings suggest that aberrant DNA methylation, independently of previously known genetic variants, plays a vital role in the pathogenesis of BD.
Chinese Clinical Trial Registry, chictr.org.cn, ChiCTR-CCC-12002184.
贝切特病（BD），一种系统性血管炎，其病因尚未完全阐明。越来越多的证据表明，异常的 DNA 甲基化可能导致 BD 的发病机制。本表观基因组全关联研究旨在鉴定汉族人群中与 BD 相关的甲基化位点。
采用 Infinium Human Methylation 450 K Beadchip 比较 60 例 BD 患者和 60 例健康对照者的全基因组 DNA 甲基化谱。通过焦磷酸测序验证 100 例 BD 患者和 100 例健康对照者的 BD 相关甲基化位点。采用实时 PCR 和 ELISA 定量检测基因表达和细胞因子产生。
共发现 4332 个与 BD 相关的差异甲基化 CpG 位点。五个差异甲基化 CpG 位点（cg03546163、cg25114611、cg20228731、cg23261343 和 cg14290576）在四个不同基因（FKBP5、FLJ43663、RUNX2 和 NFIL3）中表现出明显的低甲基化状态，并通过焦磷酸测序进行验证。验证结果表明，最显著的位点位于 FKBP5 的 5'UTR 区（cg03546163，P = 3.81E-13）。四个表现出异常甲基化状态的 CpG 位点，包括 cg03546163、cg25114611、cg23261343 和 cg14290576，可能作为 BD 的诊断标记（受试者工作特征曲线下面积 = 83.95%，95%置信区间为 78.20%，89.70%）。cg03546163 和 cg25114611 处的甲基化程度与 FKBP5 mRNA 表达呈显著负相关。用去甲基化剂 5-Aza-2'-脱氧胞苷处理后，FKBP5 mRNA 表达增加，IL-1β 产生增加。
本研究结果表明，异常的 DNA 甲基化，独立于先前已知的遗传变异，在 BD 的发病机制中起重要作用。
中国临床试验注册中心， chictr.org.cn， ChiCTR-CCC-12002184。
