Understanding Mechanisms Underlying Chronic Stress-Induced Asthma in Children by Population and Single-Cell Epigenomics Approaches

摘要 哮喘是一种严重的长期肺部疾病，在美国影响着数百万儿童。一种由 鼻病毒(RV)是哮喘发作的最常见触发因素，对患有鼻咽癌的儿童来说可能危及生命 预先存在的状况。在与哮喘相关的疾病中存在显著的种族和民族差异 非裔美国人和西班牙裔儿童更有可能被诊断为哮喘，而且显著更高 与非西班牙裔白人儿童的哮喘相关发病率比较。遗传因素单独或在 与环境暴露或生活方式的差异相结合很重要，但还没有完全 解释观察到的差异。社会环境，如种族和民族经历的慢性压力源 少数群体与感染和包括哮喘在内的慢性病的易感性增加有关。 我们假设，儿童时期的社会劣势会导致KEY的长期表观遗传变化 影响免疫细胞基因功能的调节区，对抗病毒防御和 继而增加患哮喘的风险。我们的目标是在鼻腔中结合基于群体的表观基因组图谱 单个免疫细胞分析在非洲裔美国儿童哮喘大队列中的粘膜 关于哮喘和病毒状态的详细信息，以及几个领域的慢性应激暴露。在……里面 目标1，我们将使用我们的甲基化捕获测序方法来实施表观基因组浓缩分析 对鼻黏膜完整功能甲基组(估计覆盖~3M动态CPGS)进行查询 来自数以千计的孩子。我们将在具有良好特征的儿科队列中部署该方法以探索 鼻部表观基因组特征对慢性应激、病毒感染和哮喘的预测能力 表型。在目标2中，我们将通过高通量转录和 数百名哮喘儿童的表观基因组分析采用单细胞分辨率。我们将集中我们的单细胞 暴露于高水平与低水平慢性病的RV感染儿童的血液中的分析努力 应激以表征表观遗传改变的免疫细胞信号和病毒反应机制 社会经验的结果。在目标3中，我们将进行RV反应的体外验证 儿童外周血单核细胞分化出的巨噬细胞对慢性应激不协调 曝光。我们将在体外进行详细的单细胞转录组和表观基因组图谱绘制。 感染轮状病毒，这将使我们能够量化社会劣势对免疫基因表达的影响 在基线和对轮状病毒感染的反应中。 总体而言，我们的计划将提供关于基因和社会环境如何结合起来影响的新见解 对环境应激源反应的异质性，并导致儿童健康差异 患有哮喘。

SUMMARY Asthma is a severe long-term disease of the lungs affecting millions of children in the US. An infection by Rhinovirus (RV) is the most common trigger of an asthma attack which can be life threating for children with a pre-existing condition. There are significant racial and ethnic disparities in asthma-related conditions where African American and Hispanic children are more likely to have a diagnosis of asthma and significantly higher asthma-related morbidity in comparisons with non-Hispanic white children. Genetic factors alone or in combination with differences in environment exposures or lifestyle are important but have not been able to fully explain observed disparities. Social environment such as chronic stressors experienced by racial and ethnic minority groups have been linked to increased susceptibility to infection and chronic illness including asthma. We hypothesize that social disadvantages during childhood result in long-lasting epigenetic alterations in key regulatory regions impacting immune cell gene function that negatively impacts antiviral defense and subsequently increase the risk of asthma. Our goal is to combine population-based epigenome mapping in nasal mucosa with single immune cell analysis in large pediatric asthma cohorts of African American children with detailed information about asthma and viral status as well as chronic stress exposures of several domains. In Aim 1, we will implement an epigenome enrichment assay using our Methylation Capture Sequencing approach to query the complete functional methylome in nasal mucosa (estimated to cover ~3M dynamic CpGs) derived from thousands of children. We will deploy the approach in well-characterized pediatric cohorts to explore predictive power of nasal epigenome signatures to capture chronic stress, viral infection along with asthma phenotypes. In Aim 2, we will profile the immune cell landscape by high-throughput transcriptomic and epigenome assays at single-cell resolution in hundreds of children with asthma. We will focus our single-cell profiling efforts in blood derived from RV infected children that are exposed to high vs. low levels of chronic stress to characterize immune cell signaling and viral response mechanisms epigenetically altered as a consequence of social experiences. In Aim 3, we will perform in vitro validations of RV response in primary macrophages differentiated from circulating monocytes from children that are discordant for chronic stress exposure. We will perform detailed single-cell transcriptome and epigenome mapping before and after in vitro infection with RV which will allow us to quantify the effects of social disadvantages on immune gene expression at baseline and in response to RV infection. Overall, our program will provide new insight into how genes and the social environment combine to influence heterogeneity in the response to environmental stressors and contribute to the health disparity seen in children with asthma.