Miyaso Hidenobu, Sakurai Kenichi, Takase Shunya, Eguchi Akifumi, Watanabe Masahiro, Fukuoka Hideoki, Mori Chisato
Center for Preventive Medical Sciences, Chiba University, Chiba, Japan; Department of Bioenvironmental Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan; Department of Anatomy, Tokyo Medical University, Tokyo, Japan.
Center for Preventive Medical Sciences, Chiba University, Chiba, Japan.
Environ Res. 2017 Aug;157:1-8. doi: 10.1016/j.envres.2017.05.006. Epub 2017 May 10.
H19 is a tumor-suppressor gene, and changes in the methylation of the H19-differential methylation region (H19-DMR) are related to human health. However, little is known about the factors that regulate the methylation levels of H19-DMR. Several recent studies have shown that maternal environmental factors during pregnancy, such as smoking, drinking, chemical exposure, and nutrient intake, can alter the methylation levels of several genes in fetal tissues. In this study, we examined the effects of maternal factors on changes in the methylation levels of H19-DMR in the human umbilical cord (UC), an extra-embryonic tissue. Participants from the Chiba study of Mother and Children's Health (C-MACH) were enrolled in this study. Genomic DNA was extracted from UC samples, and the methylation level of H19-DMR was evaluated by methylation-sensitive high resolution melting analysis. Individual maternal and paternal factors and clinical information for newborns at birth were examined using questionnaires prepared in the C-MACH study, a brief-type self-administered diet history questionnaire (BDHQ) during early pregnancy (gestational age of 12 weeks), and medical records. Univariate and multivariate logistic regression analyses indicated that reduced H19-DMR methylation (<50% methylation) in UC tissues was positively related to decreased head circumference in newborns [odds ratio (OR) =2.82; 95% confidence intervals (CI): 1.21-6.87; p=0.0183 and OR =2.51; 95% CI: 1.02-6.46; p=0.0499, respectively]. Moreover, multiple comparison test showed that H19-DMR methylation in UC tissues was significantly reduced in the low calorie group (intake of less than 1,000kcal/day; methylation level: 40.98%; 95% CI: 33.86-48.11) compared with that in the middle (1,000-1,999kcal/day; methylation level: 51.28%; 95% CI: 48.28-54.27) and high (≥2,000kcal/day; methylation level: 52.16%; 95% CI: 44.81-59.51) calorie groups (p=0.0054 and 0.047, respectively). In the subpopulations with low to moderate calorie intake (<2,000kcal/day), reduced H19-DMR methylation in UC tissues was significantly related to serum homocysteine concentration (OR =0.520; 95% CI: 0.285-0.875; p=0.019), maternal age (OR =1.22; 95% CI: 1.01-1.52; p=0.049), and serum folate levels (OR =0.917; 95% CI: 0.838-0.990; p=0.040). These data indicated that H19-DMR methylation levels in human UC tissues could be modulated by maternal factors during early pregnancy and may affect fetal and newborn growth.
H19是一种肿瘤抑制基因，H19差异甲基化区域（H19-DMR）的甲基化变化与人类健康相关。然而，关于调节H19-DMR甲基化水平的因素却知之甚少。最近的几项研究表明，孕期的母体环境因素，如吸烟、饮酒、化学物质暴露和营养摄入，可改变胎儿组织中多个基因的甲基化水平。在本研究中，我们调查了母体因素对人脐带（UC）（一种胚外组织）中H19-DMR甲基化水平变化的影响。来自千叶母婴健康研究（C-MACH）的参与者被纳入本研究。从UC样本中提取基因组DNA，并通过甲基化敏感高分辨率熔解分析评估H19-DMR的甲基化水平。使用C-MACH研究中编制的问卷、孕早期（孕12周）的简短型自填饮食史问卷（BDHQ）以及医疗记录，调查了个体的母体和父体因素以及新生儿出生时的临床信息。单因素和多因素逻辑回归分析表明，UC组织中H19-DMR甲基化降低（甲基化<50%）与新生儿头围减小呈正相关[比值比（OR）=2.82；95%置信区间（CI）：1.21 - 6.87；p = 0.0183以及OR = 2.51；95% CI：1.02 - 6.46；p = 0.0499]。此外，多重比较检验显示，与中等热量组（1000 - 1999千卡/天；甲基化水平：51.28%；95% CI：48.28 - 54.27）和高热量组（≥2000千卡/天；甲基化水平：52.16%；95% CI：44.81 - 59.51）相比，低热量组（摄入量<1000千卡/天；甲基化水平：40.98%；95% CI：33.86 - 48.11）中UC组织的H19-DMR甲基化显著降低（p分别为0.0054和0.047）。在低至中等热量摄入（<2000千卡/天）的亚组中，UC组织中H19-DMR甲基化降低与血清同型半胱氨酸浓度（OR = 0.520；95% CI：0.285 - 0.875；p = 0.019）、产妇年龄（OR = 1.22；95% CI：1.01 - 1.52；p = 0.049）以及血清叶酸水平（OR = 0.917；95% CI：0.838 - 0.990；p = 0.040）显著相关。这些数据表明，孕早期母体因素可调节人UC组织中的H19-DMR甲基化水平，并可能影响胎儿和新生儿的生长。
