Secondhand smoke and asthma: Mechanistic outcomes of DNA methylation in T cells

项目主任/首席调查员(最后、第一、中间)：纳多，卡里·C；米勒，雷切尔·L。 项目摘要(摘要) 暴露在二手烟(SHS)中与患哮喘的终身风险更大相关， 严重哮喘，儿童和成人哮喘住院人数增加。虽然许多人 哮喘的免疫发病机制仍不完全清楚，关键的分子事件包括 几种空气污染物对调节性T细胞(Treg)和效应性T细胞(Tef)活性的影响 包括SHS。纳多和米勒研究小组之前的结果表明，特雷格和特夫 受表观遗传调控，它们的变化影响几个哮喘基因的表达和哮喘- 相关的临床结果。虽然暴露在SHS中已被证明会导致表观遗传改变，而且 哮喘基因的表观遗传变化可能与哮喘有关，因果关系尚未得到证实 演示了。这项提案将试图建立一种新的SHS研究方法，通过确定 利用独特关联的机制研究和一项创新的研究发现SHS暴露与哮喘之间的关系 研究设计。这一建议的关键是打算在表型良好的单卵双胞胎中进行研究 (MZT)队列，包括暴露于SHS和哮喘的不一致病例，可以确定这种关联 在没有差异的情况下，SHS诱导的表观遗传标记和这种关联的时间对哮喘的影响 在遗传背景以及宫内和儿童早期环境暴露中，方法学限制 来自先前的研究。我们假设暴露在SHS中与成人当前的哮喘有关，而这 相关性是通过Treg和TJeff细胞中哮喘基因的DNA甲基化和 相应的下游细胞事件。具体地说，了解SHS诱导的机制 在哮喘和炎症的病理学方面，我们建议： 目的1：检测MZT中特定基因座CpG甲基化水平是否发生改变 还有哮喘。 目的2.确定SHS暴露的最小化是否与Foxp3甲基化的减少有关， IL-10在Treg中，干扰素在Tef中，IL-4甲基化在Tef中随时间增加。 目的3.确定Foxp3、IL-10、干扰素、IL-4的甲基化水平如何受到从未、先前(仅在 子宫或仅在儿童时期)，或哮喘和非哮喘双胞胎目前的SHS暴露 哮喘发作期的影响、相互作用及控制。 如果实现了这些目标，这项建议应该会提高我们对通过哪些机制 暴露于SHS会导致哮喘，并确定吸烟相关呼吸道疾病的新生物标志物，以便 可以更有效地制定环境政策和风险管理，并进行筛选和/或 治疗性干预可以更早地开始。 PHS 398/2590(06/09版)页面续格式页面

Program Director/Principal Investigator (Last, First, Middle): Nadeau, Kari C.; Miller, Rachel L. Project Summary (Abstract) Exposure to secondhand smoke (SHS) is associated with a greater lifetime risk of developing asthma, more severe asthma, and increased asthma hospitalizations for both children and adults. While much of the immunopathogenesis of asthma remains incompletely understood, key molecular events include changes in regulatory T cell (Treg) and effector T cell (Teff) activity in response to exposure to several air pollutants including SHS. Previous results from the Nadeau and Miller research groups suggest that Treg and Teff are epigenetically regulated, and their alterations affect the expression of several asthma genes and asthma- related clinical outcomes. While exposure to SHS has been shown to induce epigenetic alterations, and epigenetic changes in asthma genes may be associated with asthma, causal relationships have not been demonstrated. This proposal will try to establish a novel approach of SHS research by determining relationships between SHS exposure and asthma using uniquely linked mechanistic studies and an innovative study design. Key to this proposal is the intent to conduct studies in a well-phenotyped monozygotic twin (MZT) cohort including cases discordant on exposure to SHS and asthma that can determine the association of SHS-induced epigenetic marks, and the timing of this association, on asthma in the absence of differences in genetic backgrounds and in utero and early childhood environmental exposures, methodological limitations from prior studies. We hypothesize that exposure to SHS is associated with current asthma in adults, and this association is mediated through DNA methylation of asthma genes in Treg and Teff cells and the consequential downstream cellular events. Specifically, to understand the mechanisms of SHS-induced pathology in asthma and inflammation, we propose to: Aim 1: Test whether CpG methylation levels of specific genetic loci are altered in MZT discordant for smoking and asthma. Aim 2. Determine if minimization of exposure to SHS is associated with a decrease in methylation of Foxp3, IL-10, in Treg, and IFN¿ in Teff and an increase in methylation of IL-4 in Teff over time. Aim 3. Determine how methylation levels of Foxp3, IL-10, IFN¿, IL-4 are influenced by never, prior (only in utero or only childhood), or current SHS exposure in asthmatic and nonasthmatic twins by estimating main effects and interactions and controlling for period of asthma onset. If the aims are achieved, this proposal should improve our understanding of the mechanisms by which exposure to SHS contributes to asthma and identify novel biomarker of smoke-related airway disease so that environmental policy and risk management can be developed more effectively, and screening and/or therapeutic interventions may be instituted earlier. PHS 398/2590 (Rev. 06/09) Page Continuation Format Page