Elgizouli Magdeldin, Logan Chad, Nieters Alexandra, Brenner Hermann, Rothenbacher Dietrich
From the Center for Chronic Immunodeficiency (CCI) (ME, AN), University Medical Center Freiburg, Freiburg; Institute of Epidemiology and Medical Biometry (CL, DR), Ulm University, Ulm; and Division of Clinical Epidemiology and Aging Research (HB, DR), German Cancer Research Center, Heidelberg, Germany.
Medicine (Baltimore). 2015 Jan;94(1):e332. doi: 10.1097/MD.0000000000000332.
Lower respiratory tract infections (LRTIs) are a major cause of morbidity in children. DNA methylation provides a mechanism for transmitting environmental effects on the genome, but its potential role in LRTIs is not well studied. We investigated the methylation pattern of an enhancer region of the immune effector gene perforin-1 (PRF1), which encodes a cytolytic molecule of cytotoxic T lymphocytes (CTLs) and natural killer cells (NK), in cord blood DNA of children recruited in a German birth cohort in association with LRTIs in the first year of life.Pyrosequencing was used to determine the methylation levels of target cytosine-phosphate-guanines (CpGs) in a 2-stage case-control design. Cases were identified as children who developed ≥2 episodes of physician-recorded LRTIs during the first year of life and controls as children who had none. Discovery (n = 87) and replication (n = 90) sets were arranged in trios of 1 case and 2 controls matched for sex and season of birth.Logistic regression analysis revealed higher levels of methylation at a CpG that corresponds to a signal transducer and activator of transcription 5 (STAT5) responsive enhancer in the discovery (odds ratio [OR] per 1% methylation difference 1.24, 95% confidence interval [CI] 1.03-1.50) and replication (OR per 1% methylation difference 1.25, 95% CI 1.04-1.50) sets. Adjustment for having siblings <5 years old in the discovery and replication sets produced ORs of 1.19 (95% CI 0.98-1.45) and 1.25 (95% CI 1.04-1.50), respectively. Adjustment for gestational age in the replication set had no influence on the results. Methylation levels at adjacent CpGs varied with maternal age, smoking, education, and having siblings <5 years old.Our data support an association between cord blood PRF1 enhancer methylation patterns and subsequent risk of LRTIs in infants. Methylation levels at specific CpGs of the PRF1 enhancer varied according to maternal and family environmental factors suggesting a role for DNA methylation in mediating environmental influences on gene function.
下呼吸道感染（LRTIs）是儿童发病的主要原因。DNA甲基化提供了一种将环境对基因组的影响传递下去的机制，但其在LRTIs中的潜在作用尚未得到充分研究。我们调查了免疫效应基因穿孔素-1（PRF1）增强子区域的甲基化模式，该基因编码细胞毒性T淋巴细胞（CTLs）和自然杀伤细胞（NK）的一种溶细胞分子，在德国出生队列中招募的儿童脐带血DNA中，研究其与生命第一年的LRTIs的关系。采用焦磷酸测序法在两阶段病例对照设计中确定目标胞嘧啶-磷酸-鸟嘌呤（CpG）的甲基化水平。病例被确定为在生命第一年发生≥2次医生记录的LRTIs的儿童，对照为未发生LRTIs的儿童。发现组（n = 87）和复制组（n = 90）按1例和2例性别及出生季节匹配的对照组成三人小组。逻辑回归分析显示，在发现组中，与信号转导和转录激活因子5（STAT5）反应性增强子对应的一个CpG处的甲基化水平较高（每1%甲基化差异的优势比[OR]为1.24，95%置信区间[CI]为1.03 - 1.50），在复制组中也较高（每1%甲基化差异的OR为1.25，95%CI为1.04 - 1.50）。在发现组和复制组中对有<5岁兄弟姐妹进行调整后，OR分别为1.19（95%CI为0.98 - 1.45）和1.25（95%CI为1.04 - 1.50）。在复制组中对胎龄进行调整对结果没有影响。相邻CpG的甲基化水平随母亲年龄、吸烟、教育程度以及有<5岁兄弟姐妹的情况而变化。我们的数据支持脐带血PRF1增强子甲基化模式与婴儿随后发生LRTIs的风险之间存在关联。PRF1增强子特定CpG处的甲基化水平根据母亲和家庭环境因素而变化，这表明DNA甲基化在介导环境对基因功能的影响中起作用。
