Project 3: Epigenomic Consequences of Early Life Environmental Tobacco Smoke

早期生活环境烟草烟雾（ETS）暴露与神经发育的有害结果有关，包括注意力缺陷/多动障碍（ADHD），但机制尚不清楚。ETS暴露引起的表观遗传变化可能是这些关联的基础。我们的长期目标是利用DNA甲基化谱来识别有发展不良神经发育结果风险的儿童。其目的是揭示早期暴露于ETS与ADHD相关表型之间的表观遗传机制。我们假设早期ETS暴露诱导与神经发育表型相关的DNA甲基化的持续和靶向功能变化。其基本原理是，定义ETS诱导的功能性DNA甲基化变化的库将为风险分层和早期干预提供令人兴奋的新机会，以减少和预防ETS暴露的不良行为和认知结果。我们的目标如下：1）确定ETS相关的甲基化靶点。我们将检验这一假设，即大鼠早期暴露于ETS会引起可测量的 在脑和血液中均可检测到的与神经系统疾病结果相关的基因座甲基化的变化。全基因组亚硫酸氢盐测序将通过焦磷酸测序验证鉴定ETS易感基因座。2)确定ETS改变的额叶皮质甲基化表达关系。我们假设，早期生活ETS暴露在大鼠诱导额叶皮层基因表达的ADHD相关基因的变化。全转录组分析将识别这些变化。我们还将从体内结果和体外神经元分化模型中评估甲基化表达关系。3)确定DNA甲基化是否随人类ETS剂量而变化。产前和围产期的可替宁水平和儿童的DNA甲基化，从亚硫酸氢盐焦磷酸测序ADHD相关基因和候选基因座从上述目标，将确定甲基化是否随暴露而变化。这项拟议中的研究有望揭示与ETS相关的表观遗传脆弱基因，这些基因从机械上解释了ADHD与暴露于ETS之间的联系，并可能作为过去暴露的生物标志物。

Early life environmental tobacco smoke (ETS) exposure is associated with detrimental outcomes on neurodevelopment, including Attention-Deficit / Hyperactivity Disorder (ADHD), but the mechanisms are unclear. Epi-genetic changes induced by ETS exposure may underlie these associations. Our long-term goal is to utilize DNA methylation profiles to identify children at risk for developing adverse neurodevelopmental outcomes. The objective is to uncover the epigenetic mechanism linking ETS exposure in early life to phenotypes associated with ADHD. We hypothesize that early life ETS exposure induces persistent and targeted functional changes in DNA methylation that associate with neurodevelopmental phenotypes. The rationale for is that defining the repertoire of ETS-induced functional DNA methylation changes will offer exciting new opportunities for risk stratification and early interventions to reduce and prevent adverse behavioral and cognitive outcomes of ETS exposure. Our aims are as follows: 1) Identify ETS-related methylation targets. We will test the hypothesis that early life ETS exposure in rats will induce measurable shifts in methylation at loci relevant to neurobehav-loral outcomes that are detectable in both brain and blood. Whole genome bisulfite sequencing will identify ETS-vulnerable loci with validation by pyrosequencing. 2) Identify ETS-altered methylation-expression relationships in frontal cortex. We hypothesize that early life ETS exposure in rats induces changes in frontal cortex gene expression at ADHD-relevant genes. Whole transcriptome profiling will identify these changes. We will also evaluate methylation expression relationships from the in vivo results and in an in vitro model of neuronal differentiation. 3) Determine if DNA methylation varies with ETS dose in humans. Prenatal and peri-natal cotinine levels and DNA methylation in children, from bisulfite pyrosequencing at ADHD-related genes and candidate loci from the above aims, will determine if methylation varies with exposure. The proposed research is expected to reveal ETS-related epigenetically vulnerable genes that mechanistically explain the link between ADHD and exposure to ETS and that may serve as biomarkers of past exposure.