HuR in Allergic Asthma and T Cell Differentiation

描述(申请人提供)：由于未知的原因，过敏和哮喘的发病率在美国持续增加。越来越清楚的是，哮喘是一种具有不同内型的异质性疾病，这意味着不同的病理生理学。在人类中，哮喘以过敏性和非过敏性形式存在。更好地了解哮喘内型的不同机制是该领域尚未得到满足的需求。全基因组芯片分析已经鉴定出许多哮喘相关基因。然而，由于稳态信使核糖核酸水平和蛋白质之间的相关性很差，转录转录方法可能会忽略关键基因。RNA结合蛋白(RBPs)和microRNAs(MiRNAs)对转录后基因的调控日益被认为是促炎基因的重要调控机制。限制性商业惯例，如Hur(Elav1)，与富含AU的元素(Ares)结合，通过稳定靶基因mRNAs和增加可译性，在协调调节哮喘的促炎基因方面发挥关键作用。我们的实验室和其他实验室使用的方法，称为应用于微阵列的RNA免疫沉淀(RIP-Chip)，已经确定了限制性商业惯例是如何协调调节炎症的。转录后基因调控在CD4T细胞分化中起着重要作用，但人们对这些过程知之甚少。我们的长期目标是了解转录后基因在呼吸道炎症中的调控。这项应用的目标是了解HUR在过敏原攻击过程中如何调节关键分子，如Th2/Th17细胞因子和IL-2，这是我们追求这一目标的下一步。其核心是RBP，HUR，是CD4Th2介导的过敏性气道炎症的发生和正常IL-2稳态表达所必需的。这一建议的基本原理是，我们的研究表明，HUR同时控制Th2和Th17的分化。Hur KO小鼠不会因为Th2细胞因子的产生受到抑制而出现呼吸道炎症，也不会在T细胞激活后关闭IL-2的表达。了解IL-2和Th2/Th17细胞因子基因调控的转录后机制将使该领域能够调节和影响过敏原驱动的哮喘炎症反应的结果，并可能有助于更好地确定哮喘内型之间的异质性。我们计划测试中枢ESI并通过以下四个特定目标来实现这些目标：1)HUR消融是否改变了CD4Th亚群的分化？2)确定HUR是否是体内过敏性呼吸道炎症所必需的；3)IL-2和Th2细胞因子表达的机制决定因素；4)确定人类淋巴细胞是否存在HUR表达异常。我们相信我们的研究是创新的，因为这些方法将为T细胞转录后细胞因子调控提供新的机械性见解。这项拟议的研究意义重大，因为它将阐明呼吸道反应如何在分子水平上与适应性免疫和先天免疫联系起来，以控制肺部炎症。

DESCRIPTION (provided by applicant): For unknown reasons, the incidence of allergies and asthma continues to increase in the US. It is increasingly clear that asthma is a heterogeneous disease with differing endotypes which suggest discrete pathophysiology. In humans, asthma exists in allergic and non-allergic forms. It is an unmet need in the field to better understand ho different mechanisms contribute to asthma endotypes. Genome wide array analysis has identified many asthma relevant genes. However, due to poor correlation between steady state mRNA levels and protein, transcriptomic approaches may overlook critical genes. Posttranscriptional gene regulation by RNA binding proteins (RBPs) and microRNAs (miRNAs) are increasingly recognized as important control mechanisms for proinflammatory genes. RBPs, such as HuR (elav1) which bind to AU-rich elements (AREs) play critical roles in coordinately regulating proinflammatory genes in asthma by stabilizing target gene mRNAs and increasing translatability. Methods used by our lab and others, called RNA immunoprecipitation applied to microarrays (RIP-Chip) have identified how RBPs are coordinately regulating inflammation. Posttranscriptional gene regulation plays an important role in CD4+ T differentiation, yet these processes are poorly understood. Our long term goal is to understand posttranscriptional gene regulation in airway inflammation. The objective of this application, which is our next step in pursuit of that goal, is to understand how HuR is regulating key molecules, such as Th2/Th17 cytokines and IL-2 during allergen challenge. The central esis is that the RBP, HuR, is permissive for development of CD4+ Th2 mediated allergic airway inflammation and required for normal IL-2 homeostatic expression. The rationale for this proposal is that our work has demonstrated that HuR controls both Th2 and Th17 differentiation. HuR KO mice do not develop airway inflammation due to suppression of Th2 cytokine production and do not have the ability to turn off IL-2 expression following T cell activation. Understanding posttranscriptional mechanisms of IL-2 and Th2/Th17 cytokine gene regulation will allow the field to modulate and affect outcomes of inflammatory responses in allergen driven asthma and also perhaps aid in better defining the heterogeneity amongst asthma endotypes. We plan to test the central esis and accomplish these objectives by the following four specific aims: 1) Does HuR ablation alter CD4+ Th subset differentiation?; 2) Determine whether HuR is required for allergic airway inflammation in vivo; 3) Mechanistic determinants of IL-2 and Th2 cytokine expression; 4) Determine whether human lymphocytes have dysregulated HuR expression. We believe our study is innovative, because such approaches will provide novel mechanistic insights into T cell posttranscriptional cytokine regulation. The proposed research is significant, because it will elucidate how airway responses connect at the molecular level with both adaptive and innate immunity to control lung inflammation.