Exposure in Epigenetic Regulation of Immune Response in CBD

描述（由申请人提供）：本研究的目的是确定环境诱导的表观遗传标记及其对导致肉芽肿性肺病、慢性铍病（CBD）的基因表达的影响。这项研究依赖于我们独特的合格调查团队的专业知识和优势。这项研究将确定CBD的致病途径和风险因素，CBD是这种疾病（铍致敏; BeS）和类似环境引起的疾病的前兆。在遗传易感宿主的环境中暴露于吸入的Be抗原，引发Th 1免疫应答，在CD 4 + T细胞的背景下，抗原呈递通过抗原呈递细胞（APC）上的HLA II类发生。随后，CD 4 + T细胞和APC被募集到肺中，增殖，产生细胞因子和趋化因子，并最终形成肉芽肿。在CBD和BeS中发现在氨基酸位置69（E69）处具有谷氨酸的HLA-DPB 1等位基因的患病率增加。在没有BeS或CBD的Be暴露工人中可以发现高达40%的相同多态性，这表明除了暴露之外，其他易感因素或遗传调节形式在疾病发病机制中必须是重要的。在其他免疫介导的疾病中，越来越多的数据表明，表观遗传机制与遗传易感性和环境相结合，可能有助于解释疾病风险。表观遗传修饰通过DNA甲基化和FOXP 3等关键基因的组蛋白修饰决定Th 1与Th 2免疫应答，从而影响健康和疾病。迄今为止，尚未在环境诱导的肉芽肿性疾病中探索表观遗传学改变。我们的初步数据表明，与BeS相比，CBD中暴露和疾病部位（肺）的关键免疫反应基因和网络的全基因组DNA甲基化差异显着。基于这些信息，该提议的总体假设是表观遗传机制影响基因表达和免疫细胞分化，最终影响肉芽肿性肺病的风险。使用整合的基因组方法，我们将首先定义表观遗传学改变（全基因组甲基化）在CD 4+肺细胞，有和没有铍暴露在CBD，BeS和正常对照的病例对照研究。随后，我们将确定影响基因转录的功能性甲基化改变，这些信息将扩大我们对CBD发病机制的理解。由于去甲基化剂，如5-氮杂胞苷（AZA）和地西他滨目前被用于治疗免疫介导的疾病，我们将评估经验证的甲基化和基因表达靶标的变化，用去甲基化（AZA）或甲基化（叶酸）剂治疗CBD、BeS和对照CD 4+肺细胞。本研究将提供与这类药物作为治疗靶点相关的数据。此外，随着我们对表观基因组的了解不断加深，从这一提议中获得的信息将揭示其他暴露相关的非感染性肉芽肿性疾病的发病机制，以及基因组与暴露的关系。

DESCRIPTION (provided by applicant): The goal of this study is to define the environmentally induced epigenetic marks and their impact on gene expression that result in the granulomatous lung disease, chronic beryllium disease (CBD). The study relies on the expertise and strengths of our uniquely qualified investigative team. This study will define pathogenic pathways and risk factors for CBD, the precursor to this disease (beryllium sensitization; BeS) and similar environmentally induced diseases. Exposure to an inhaled Be antigen(s) in the setting of a genetically susceptible host, initiates a Th1 immune response, with antigen presentation occurring via HLA Class II on antigen presenting cell (APC) in the context of CD4+ T cells. Subsequently, CD4+ T cells and APCs are recruited to the lung, proliferate, produce cytokines and chemokine's, and eventually form granulomas. An increased prevalence of HLA-DPB1 alleles with a glutamic acid at amino acid position 69 (E69) is found in CBD and BeS This same polymorphism may be found in up to 40% of Be exposed workers without BeS or CBD, suggesting that other susceptibility factors or forms of genetic regulation must be important in disease pathogenesis, in addition to exposure. Growing data in other immune-mediated diseases suggests that epigenetic mechanisms in combination with genetic susceptibility and environment may help explain disease risk. Epigenetic modifications determine the Th1 versus Th2 immune response through DNA methylation and histone modifications of key genes such as FOXP3, and thus impact health and disease. To date epigenetic alterations have not been explored in environmentally induced granulomatous diseases. Our preliminary data demonstrate significant genome-wide DNA methylation differences in pivotal immune response genes and networks at the site of exposure and disease, the lung, in CBD compared to BeS. Based on this information, the overarching hypothesis for this proposal is that epigenetic mechanisms impact gene expression and immune cell differentiation, ultimately impacting the risk of granulomatous lung disease. Using an integrated genomic approach we will first define epigenetic alterations (genome wide methylation) in CD4+ lung cells, with and without beryllium exposure in a case control study of CBD, BeS and normal controls. Subsequently, we will determine functional methylation alterations that impact gene transcription, information which will expand our understanding of the pathogenesis of CBD. As demethylating agents, such as 5- azacytidine (AZA) and decitabine are currently being used to treat immune mediated diseases, we will evaluate changes in validated methylation and gene expression targets treating CBD, BeS and control CD4+ lung cells with demethylating (AZA) or methylating (folic acid) agents. This study will provide data relevant to this class of agents as targets for therapy. Furthermore, the information gained from this proposal will shed light on the pathogenesis of other exposure related non-infectious granulomatous diseases, and on genome-exposure relationships, as our understanding of the epigenome grows.