Molecular mechanisms of posttranscriptional gene regulation in asthmatic airway inflammation

哮喘仍然是一种难以治疗的疾病，极大地影响了部署的军事人员和退伍军人。 目前使用的药物：1）非常昂贵（生物制剂），给VA带来巨大负担 2）具有显著的副作用（口服类固醇）;或3）在某些内型中不起作用，例如， 类固醇抵抗性哮喘由于稳态mRNA水平和蛋白质之间的不一致性，转录组学 这些方法可能忽略了由RNA结合蛋白（RBP）调控的基因。转录后基因调控 RBP和microRNA（miRNAs）的作用越来越被认为是一种重要的控制机制， 炎症基因，但研究不足。RBP，如HuR（Elavl 1），与mRNA富含AU的元件结合 ARE通过调节mRNA的稳定性和关键促炎基因表达的翻译发挥关键作用 哮喘病我们最近发表的数据表明，小鼠中的HuR消融改善了过敏原驱动的肺 炎症此外，HuR在哮喘CD 4 + T细胞中过表达，其抑制可减少细胞因子 表情利用RNA免疫沉淀技术（RIP-seq）结合基因工程鼠 模型，我们已经证明HuR控制Th 2和Th 17 CD 4 + T谱系。没有更好的 理解炎症的转录后控制，该领域将继续有一个有限的洞察力， 分子机制，这可能有助于哮喘内源性和不平等的治疗反应， 患者的结果。我们的长期目标是了解不同基因表达水平下的转录后基因调控。 哮喘气道炎症的内型。本申请的目的是确定HuR和TTP 家族成员调节不同哮喘中CD 4 + T细胞产生的关键促炎分子 内型我们的基本原理是，HuR驱动的基因表达的调查将确定分子机制 不同哮喘内源型之间的差异，特别是2型高与非2型高。核心假设是 CD 4 + T细胞中的HuR-Gata 3相互作用控制2型高哮喘中的气道炎症（由哮喘引起）。 Gata 3）和非2型高哮喘（由IL 17驱动）。我们计划测试中心假设， 这些目标通过以下三个具体目标：1）定义HuR调节的分子机制， 2）阐明人CD 4 + T细胞基因簇，其允许2型高气道炎症; 哮喘肺部炎症和3）确定HuR抑制对T细胞介导的炎症的影响， 2高和非2型高哮喘。在拟议的研究完成后，我们的预期成果是 确定HuR如何控制CD 4 + T细胞的分化和功能，这对发展至关重要。 过敏性气道炎症预计这些成果将对外地产生持续的积极影响 因为它们将进一步确定区分2型高与非2型高哮喘的分子机制 内型所获得的基本重要知识将为开发新疗法提供机会 通过干扰HuR功能来治疗哮喘性肺部炎症，包括类固醇抵抗性哮喘。

Asthma remains a difficult to treat disease that greatly impacts deployed military personnel and Veterans. Currently used medications either: 1) are very expensive (biologics), placing enormous burdens on the VA Healthcare System; 2) have significant side effects (oral steroids); or 3) do not work in some endotypes, e.g., steroid-resistant asthma. Due to discordance between steady-state mRNA levels and protein, transcriptomic approaches may overlook genes regulated by RNA binding proteins (RBPs). Posttranscriptional gene regulation by RBPs and microRNAs (miRNAs) is increasingly recognized as an important control mechanism for pro- inflammatory genes but understudied. RBPs, such as HuR (Elavl1), which binds to mRNA AU-rich elements (AREs), play critical roles by regulating mRNA stability and translation of key pro-inflammatory gene expression in asthma. Our recently published data indicates that HuR ablation in mice ameliorates allergen-driven lung inflammation. Furthermore, HuR is over-expressed in asthmatic CD4+ T cells and its inhibition reduces cytokine expression. Using RNA Immunoprecipitation techniques (RIP-seq) combined with genetically engineered murine models, we have demonstrated that HuR controls both Th2 and Th17 CD4+ T lineages. Without a better understanding of posttranscriptional control of inflammation, the field will continue to have a limited insight into molecular mechanisms, which likely contribute to asthma endotypes and unequal treatment responses and outcomes in patients. Our long-term goal is to understand posttranscriptional gene regulation in different endotypes of asthmatic airway inflammation. The objective of this application is to determine how HuR and TTP family members regulate key pro-inflammatory molecules produced by CD4+ T cells in different asthma endotypes. Our rationale is that investigation of HuR-driven gene expression will identify molecular mechanisms that differ between asthma endotypes, especially type 2-high vs. non-type 2-high. The central hypothesis is that the HuR-Gata3 interaction in CD4+ T cells controls airway inflammation in type 2-high asthma (driven by Gata3) and in non-type 2-high asthma (driven by Il17). We plan to test the central hypothesis and accomplish these objectives by the following three specific aims: 1) Define molecular mechanisms of HuR regulation in murine models of type 2-high airway inflammation; 2) Elucidate human CD4+ T cell gene clusters permissive for asthmatic lung inflammation and 3) Determine effects of HuR inhibition on T cell-mediated inflammation in type 2 high and non-type 2 high asthma. At the completion of the proposed research, our expected outcomes are to identify how HuR controls CD4+ T cell differentiation and function, which are critical for the development of allergic airway inflammation. These results are anticipated to have a sustained positive impact upon the field because they will further define molecular mechanisms distinguishing type 2 high from non-type 2 high asthma endotypes. The fundamentally important knowledge gained will provide opportunities to develop novel therapies to treat asthmatic lung inflammation by interfering with HuR function, including in steroid-resistant asthma.