Mechanisms and Consequences of Gene Induction by Glucocorticoids in Airway Smooth Muscle

糖皮质激素(GC，通称为“类固醇”)是控制多种疾病的非常有效的药物。 各种免疫介导性疾病，包括哮喘。它们也被用来治疗病毒引起的炎症。 在哮喘加重的情况下。通过减少呼吸道平滑肌等组织的炎症 (ASM)，吸入GC对大多数哮喘患者非常有效，而全身治疗，即 引起副作用，用于治疗哮喘加重。尽管使用了最好的疗法，但仍有100多万人 美国人继续受到难以控制的哮喘和频繁加重的困扰。因此，新的 针对肺部类固醇信号机制的药理学方法，包括ASM，是迫切需要的。 需要改进哮喘的治疗。 GCS的主要生化功能是与GC受体(GR)结合，导致转录调节 直接通过GR，这是一种转录因子。ASM是GCs在哮喘中的关键靶向组织，ASM表现为 哮喘的超缩性、重塑和细胞因子的活跃表达。之前开发类固醇的努力- 控制通路作为一种改进针对ASM的哮喘治疗的方法已经建立在SO的基础上 被称为GR活性的“反式抑制”模型，其中GR被认为通过拮抗作用来减轻炎症 与促炎转录因子如NFkB结合。与教条完全相反，这笔赠款 相反，应用的重点是GR的转录诱导以及GR和NFkB之间的合作。我们的 初步数据表明，GR-NFkB的合作是控制ASM炎症的核心，因此很可能 对类固醇的疗效有显著贡献。从机制上讲，我们的数据表明这条途径包括 增强子RNA的转录和染色质环的形成，我们的数据也表明这一机制是 可下药的。基于我们关于GR诱导通路的有希望的发现，我们还创造了一种新的方法来 询问GR诱导的增强子RNA签名，以寻找与哮喘的遗传联系。我们最重要的假设是 GR介导的转录诱导和GR-NFkB在ASM中的协同作用对类固醇的疗效至关重要 哮喘和这些途径与发展成哮喘的风险有关。我们将用三个例子来检验这一假设 具体目标，这也将解决关键的分子知识差距。在目标1中，我们将确定 由GR/NFkB协同诱导的一套全面的增强子RNA，并确定这些 增强子RNA环连接到抗炎基因的启动子。在目标2中，我们将确定DNA序列 GR和NFkB在合作监管中的要求和其他因素，我们将测试 这一途径在翻译模型中的治疗相关性。在目标3中，我们将确定新的遗传关联 SNPs、GR诱导增强剂和哮喘之间的关系，我们将确定这些SNPs与GR的相关性。 信令和ASM功能。

Glucocorticoids (GCs, generically known as “steroids”) are exceptionally effective drugs in the control of a wide variety of immune-mediated diseases, including asthma. They are also used to treat viral-induced inflammation in the context of asthma exacerbations. Through reducing inflammation in tissues such as airway smooth muscle (ASM), inhaled GCs are very effective in the majority of asthma patients, whereas systemic therapy, which causes side effects, is used to treat asthma exacerbations. Despite using best therapies, over one million Americans continue to be afflicted with difficult-to-control asthma and frequent exacerbations. Thus, new pharmacologic approaches aimed at steroid signaling mechanisms in the lung, including ASM, are urgently needed to improve treatment for asthma. GCs primary biochemical function is to bind to the GC receptor (GR), leading to regulation of transcription directly by GR, which is a transcription factor. ASM is a key target tissue of GCs in asthma, and ASM exhibits hyper-contractility, remodeling and exuberant cytokine expression in asthma. Previous efforts to exploit steroid- controlled pathways as a method to improve asthma therapies directed at ASM have been predicated on the so called “transrepression” model of GR activity, in which GR is thought to reduce inflammation by antagonistic tethering to pro-inflammatory transcription factors such as NFkB. Entirely contrary to dogma, this grant application is focused instead on transcriptional induction by GR and cooperation between GR and NFkB. Our preliminary data implicate GR-NFkB cooperation as central to controlling inflammation in ASM, thus likely contributing significantly to efficacy of steroids. Mechanistically, our data suggest this pathway involves transcription of enhancer RNAs and formation of chromatin loops, and our data also suggest this mechanism is druggable. Based on our promising findings on GR-induced pathways, we have also created a novel method to interrogate GR-induced enhancer RNA signatures for genetic links to asthma. Our overarching hypothesis is that GR-mediated transcriptional induction and GR-NFkB cooperation in ASM is crucial for steroid efficacy in asthma and these pathways are linked to risk of developing asthma. We will test this hypothesis with three specific aims, which will also address crucial molecular knowledge gaps. In Aim 1, we will determine the comprehensive set of enhancer RNAs that are induced cooperatively by GR/NFkB and determine if these enhancer RNAs loop to the promoters of anti-inflammatory genes. In Aim 2, we will determine the DNA sequence requirements and additional factors involved in cooperative regulation by GR and NFkB, and we will test the therapeutic relevance of this pathway in translational models. In Aim 3, we will identify novel genetic associations between SNPs, GR-induced enhancers and asthma, and we will determine the relevance of these SNPs to GR signaling and ASM function.