Microbiome in Asthma Induced by Environmental Particle Exposure

哮喘由环境暴露引发或恶化，并与表观遗传变化有关 在人类和动物模型中。肠道和肺部的微生物失调越来越多地与 哮喘的发病率和严重程度，但缺乏因果关系研究。我们已经改装了一个小鼠模型 重点是在子宫内暴露于环境颗粒物后，在生命早期发生过敏性哮喘。 研究微生物群在哮喘发病中的作用。在这个模型中，我们已经证明了母体接触 (对过敏原或颗粒物，如城市集中空气颗粒(CAP)、柴油废气颗粒物(DEP)和 二氧化钛颗粒(二氧化钛)会在几代人的后代中引发哮喘风险增加。人类 广泛暴露在这些颗粒物中，特别是在城市和工业环境中，那里的发病率 哮喘的发病率也更高。我们发现，这些新生儿对哮喘的准备增加与 随着关键免疫细胞-树突状细胞(DC)DNA甲基化的变化，树突状细胞(DC)在哮喘发病中是必不可少的。 重要的悬而未决的问题是为什么会发生这些表观遗传变化，以及是否存在因果联系 哮喘中出现的异常微生物群。我们假设，在子宫内暴露在颗粒物中会改变 怀孕小鼠及其后代的微生物群，然后向免疫细胞发出信号， 使后代容易过敏。 在具体目标1中，我们将测试母体微生物群(肠道、肺和阴道)在分娩后发生的变化 孕期颗粒暴露，因为母体菌群在很大程度上为新生儿的微生物群提供了种子。纵向 图谱分析将采用多方面的方法，包括16S/ITS分类图谱、元基因组测序 以及靶向代谢组学，用于全面分析微生物的组成和代谢。 在具体目标2中，我们将通过类似的纵向剖面图检查新生儿肠道微生物组，包括 他们对过敏原的反应和哮喘表型的建立。重要的是，我们将执行因果关系 通过从“高危哮喘”捐赠者幼崽(出生于 粪便微生物区系移植(FMT)。最后，我们 将测试FMT对受体DC表观基因组的影响。 在具体目标3中，我们将类似地描绘新生儿肺微生物组，并将测试抗生素的效果- 基于哮喘准备过程中异常肺微生物区系的变化。 意义：在这里，我们假设哮喘发病的两种潜在的相互关联的机制： 表观遗传学和微生物组。免疫细胞的表观遗传变化和肠道和肠道的生物失调 在人类和小鼠模型中，肺与哮喘有关，但缺乏因果关系研究。建议数 一项研究解决了这一知识缺口，旨在测试相对常见的 暴露在环境中。

Asthma is triggered or worsened by environmental exposures and is associated with epigenetic changes in humans and animal models. Microbial dysbiosis in the gut and the lung is increasingly being associated with the incidence and severity of asthma, however causality studies are lacking. We have adapted a mouse model that focuses on the ONSET of allergic asthma early in life after an in utero exposure to environmental particles to study how microbiome may lead to the asthma onset. In this model, we have shown that maternal exposures (to allergen or particulate matter, e.g. concentrated urban air particles (CAP), diesel exhaust particles (DEP) and titanium dioxide particles (TiO2), trigger increased asthma risk in several generations of the offspring. Humans are widely exposed to these particulates, especially in urban and industrial settings, where the incidence of asthma is also higher. We found that the increased ‘preparedness’ for asthma in these neonates is associated with DNA methylation changes in key immune cells – dendritic cells (DC) that are essential in asthma origin. Important unanswered questions are why these epigenetic changes occur, and whether there is a causative link to the aberrant microbiome seen in asthma. We hypothesize that in utero exposures to particles alter the microbiome of the pregnant mice and their offspring, which then signals to the immune cells in a way that predisposes the offspring to allergy. In Specific Aim 1, we will test what happens to the maternal microbiome (gut, lung and vaginal) after the gestational particle exposure, as it is the maternal flora that largely seeds the neonate’s microbiome. Longitudinal profiling will employ a multifaceted approach, including 16S/ITS taxonomic profiling, metagenomic sequencing and targeted metabolomics, for the comprehensive analysis of the composition and metabolism of the microbes. In Specific Aim 2, we will examine the neonatal gut microbiome via similar longitudinal profiling, including their response to allergen and establishment of the asthma phenotype. Importantly, we will perform causality experiments by transferring the hypothetically aberrant flora from the “asthma-at-risk” donor pups (born to the dams treated with particles) to normal recipients, and vice versa: fecal microbiota transplant (FMT). Finally, we will test the effect of the FMT on the recipient’s DC epigenome. In Specific Aim 3, we will similarly profile neonatal lung microbiome and will test the effect of antibiotic- based alteration of the aberrant lung microflora on asthma preparedness. Significance: Here we postulate two, potentially interconnected, mechanisms in asthma onset: epigenetics and the microbiome. Both the epigenetic alterations in immune cells and the dysbiosis in the gut and lung have been linked to asthma in humans and mouse models but causality studies are lacking. The proposed research addresses this gap in knowledge in a study designed to test basic mechanisms of relatively common environmental exposures.