Epigenetic Regulation of Immune Pathways in Sarcoidosis

项目摘要/摘要 这项研究的目标是定义表观遗传标记及其对基因表达的影响，从而导致 肉芽肿性肺部疾病、结节病和两种最常见的进行性结节病表型 肺部疾病和缓解性疾病。这项研究依赖于我们独特的 合格的调查团队。它将定义结节病的致病途径和危险因素，以及两种常见的 疾病的表型，并对类似的免疫介导性疾病有影响。在结节病中，它似乎 在遗传易感宿主的环境中暴露于未知的吸入性抗原(S)，启动Th1 免疫应答，通过抗原提呈细胞(APC)上的HLAII类递呈发生 CD4T细胞的背景。随后，CD4T细胞和APC被招募到肺中，增殖，产生 细胞因子和趋化因子，最终形成肉芽肿。人类白细胞抗原-DRB1等位基因的增加是 在结节病中发现，尽管确切的等位基因因个人的种族、民族背景和 疾病表型。与结节病相关的其他遗传变异数量有限，这表明 其他易感因素或遗传调节形式在疾病发病机制中肯定是重要的。 其他肺部疾病的不断增长的数据表明，表观遗传机制与遗传 易感性和环境可能有助于解释疾病风险。表观遗传修饰决定Th1与 通过DNA甲基化和组蛋白修饰关键基因如FOXP3和 从而影响健康和疾病。到目前为止，在结节病中还没有发现表观遗传学改变。我们的 初步数据显示全基因组DNA甲基化在关键免疫反应中存在显著差异 结节病患者暴露部位和疾病部位的基因和网络，即肺，与无 肉芽肿性肺部疾病。根据这一信息，这一提议的首要假设是DNA 关键免疫通路基因甲基化变化影响基因表达和免疫细胞 分化，因此有患结节病的风险。使用整合的基因组方法，我们将首先定义 在进展性和非进展性结节病病例对照研究中，CD4肺细胞的表观遗传学改变 疾病缓解期和正常对照组。随后，我们将确定功能性甲基化改变 影响基因转录的信息，将扩大我们对结节病发病机制的认识。 作为去甲基剂，如5-氮胞苷(AZA)和地西他滨目前正被用于治疗免疫 介导性疾病，我们将评估有效甲基化和基因表达靶点治疗的变化 使用去甲基化(AZA)或甲基化(叶酸)试剂的结节病CD4肺细胞。这项研究将提供 与作为治疗目标的这类药物相关的数据。此外，从这项提案中获得的信息 将阐明结节病的发病机制及其表型，以及基因组与暴露的关系。

PROJECT SUMMARY/ABSTRACT The goal of this study is to define the epigenetic marks and their impact on gene expression that result in the granulomatous lung disease, sarcoidosis, and two of the most common sarcoidosis phenotypes, progressive pulmonary disease and remitting disease. The study relies on the expertise and strengths of our uniquely qualified investigative team. It will define pathogenic pathways and risk factors for sarcoidosis and two common phenotypes of disease, and have implications for similar immune mediated diseases. In sarcoidosis, it appears that exposure to an unknown inhaled 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 chemokines, and eventually form granulomas. An increased prevalence of HLA-DRB1 alleles is found in sarcoidosis, although the exact alleles vary based on an individual's race, ethnic background and disease phenotype. There are a limited number of other genetic variants associated with sarcoidosis, suggesting that other susceptibility factors or forms of genetic regulation must be important in disease pathogenesis. Growing data in other lung 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 sarcoidosis. 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 sarcoidosis compared to subjects without granulomatous lung disease. Based on this information, the overarching hypothesis for this proposal is that DNA methylation changes in genes in key immune pathways impact gene expression and immune cell differentiation, and thus risk of sarcoidosis. Using an integrated genomic approach we will first define epigenetic alterations in CD4+ lung cells, in a case control study of sarcoidosis cases with progressive and remitting disease and normal controls. Subsequently, we will determine functional methylation alterations that impact gene transcription, information which will expand our understanding of the pathogenesis of sarcoidosis. 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 sarcoidosis 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 sarcoidosis and its phenotypes and on genome-exposure relationships.