Epigenetic Regulation of Immune Pathways in Sarcoidosis

项目概要/摘要 本研究的目的是确定表观遗传标记及其对基因表达的影响，从而导致 肉芽肿性肺疾病，结节病，和两种最常见的结节病表型，进行性 肺病和缓解性疾病。这项研究依赖于我们独特的专业知识和优势， 合格的调查团队它将确定结节病的致病途径和危险因素， 表型的疾病，并具有类似的免疫介导的疾病的影响。在结节病中， 在遗传易感宿主的环境中暴露于未知的吸入抗原，启动Th 1 免疫应答，其中抗原呈递通过HLA II类在抗原呈递细胞（APC）上发生， CD 4 + T细胞。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。HLA-DRB 1等位基因的患病率增加， 在结节病中发现，尽管确切的等位基因根据个体的种族，种族背景和 疾病表型与结节病相关的其他遗传变异数量有限，表明 其他易感因素或遗传调节形式在疾病发病机制中一定很重要。 在其他肺部疾病中越来越多的数据表明，表观遗传机制与遗传机制相结合， 易感性和环境可能有助于解释疾病风险。表观遗传修饰决定了Th 1与 通过关键基因如FOXP 3的DNA甲基化和组蛋白修饰的Th 2免疫应答，以及 从而影响健康和疾病。迄今为止，尚未探讨结节病的表观遗传学改变。我们 初步数据表明，关键免疫应答中存在显著的全基因组DNA甲基化差异 结节病中暴露和疾病部位（肺）的基因和网络与未暴露的受试者相比， 肉芽肿性肺病基于这些信息，这个提议的首要假设是，DNA 关键免疫途径中基因的甲基化变化影响基因表达和免疫细胞 分化，因此结节病的风险。使用整合的基因组方法，我们将首先定义 在进行性结节病病例的病例对照研究中， 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，这将扩大我们对结节病发病机制的理解。 作为去甲基化剂，例如5-氮杂胞苷（AZA）和地西他滨目前被用于治疗免疫性疾病。 介导的疾病，我们将评估有效的甲基化和基因表达靶点治疗的变化， 结节病CD 4+肺细胞与去甲基化（AZA）或甲基化（叶酸）试剂。本研究将提供 与作为治疗靶标的这类药剂相关的数据。此外，从该提案中获得的信息 将阐明结节病的发病机制及其表型和基因组暴露关系。

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.