Translational Regulation in Bronchial Epithelial Cells

支气管上皮细胞的翻译调控

• 批准号: 7929075
• 负责人: Ann-Bin Shyu
• 金额: $ 37.5万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-23 至 2011-07-24
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7929075
• 关键词: Air; Airborne Particulate Matter; Allergens; Allergic; Antigens; Asthma; Attenuated; Binding Proteins; Biochemical; CCL2 gene; Cell Culture Techniques; Cell Nucleus; Cell model; Cells; Chemicals; Chronic; Chronic Obstructive Airway Disease; Code; Collagen Gene; Complex; Cytoplasm; Cytoplasmic Tail; Data; Dendritic Cells; Development; Disease; Elements; Environment; Epithelial; Epithelial Cells; Exposure to; Feedback; Gene Expression; Genes; Health; Homeostasis; Human; IL8 gene; Immune response; Immunity; In Vitro; Indium; Infectious Agent; Inflammation; Inflammation Mediators; Inflammatory; Inflammatory Response; Interleukin-4; Interleukin-6; Lead; Link; Liquid substance; Lung Inflammation; Maintenance; Mediating; Mediator of activation protein; Messenger RNA; MicroRNAs; Modeling; Molecular; Participant; Pathogenesis; Patients; Play; Post-Transcriptional Regulation; Process; Production; Proteins; RNA; RNA Processing; Regulation; Repression; Role; Source; Testing; Th2 Cells; Transcriptional Activation; Translating; Translation Initiation; Translational Regulation; Translational Repression; Translations; Untranslated Regions; airway epithelium; airway inflammation; allergic airway inflammation; base; bronchial epithelium; chemokine; cytokine; design; in vivo; insight; knock-down; mRNA Decay; mRNA Stability; mouse model; novel; novel therapeutic intervention; translation factor

Epithelial cells of the bronchial airways are directly exposed to the environment and are the first line of defense against airborne particulate matter, allergens and infectious agents. During allergic airway inflammation the epithelium is both a source of mediator production as well as a target of remodeling processes. Thus, bronchial epithelial cells play a critical role not only in the maintenance of physico-chemical homoeostasis of the airways but also in the pathogenesis of airway diseases. Yet, little is known about the post-transcriptional regulation of mediator, effector and remodeling gene expression in these cells during the inflammatory response. Using two in vitro cell models and an in vivo mouse model for allergic airway inflammation, our preliminary studies support the following model: Upon IL-4/TNF-α stimulation, transcriptional activation results in an influx of inflammatory mediator mRNAs into the cytoplasm, where microRNA (miRNA)-mediated translation repression is released, global translation increases, and P-bodies (cytoplasmic domains for storage and/or degradation of translationally repressed mRNAs) disassembled. These concerted post-transcriptional activities help the cell deal with a rapid demand for translating inflammatory mediator mRNAs into proteins. After a persistent exposure to IL-4/TNF-α, translocation of HuR, an AU-rich element (ARE) binding protein, from the nucleus to the cytoplasm is elicited in activated bronchial epithelial cells. HuR then associates with cytoplasmic ARE-containing mRNAs coding for inflammatory mediators to down-regulate their translation, thereby dampening the inflammatory response. The following specific aims are designed to test this model: 1) To elucidate the molecular and biochemical mechanisms that alter the function of miR-155, an miRNA closely linked to immunity, in activated bronchial epithelial cells and to define the role of miR-155 in regulating inflammatory mediator gene expression in bronchial epithelial cells; 2) To determine whether a reduction in P-bodies is a hallmark of activated bronchial epithelial cells and how alteration of P-body assembly and disassembly influences the inflammatory responses in bronchial epithelial cells; and 3) To determine how HuR down-regulates the expression of inflammatory mediator molecules such as MCP-1 in activated bronchial epithelial cells and how altering HuR expression in bronchial epithelium modulates allergic airway inflammation. The proposed studies will provide important mechanistic insights into the post-transcriptional mechanisms operating in bronchial epithelial cells to regulate their inflammatory responses, thereby leading to the development of new therapeutic approaches to alleviate airway inflammation associated with chronic airway diseases such as asthma and chronic obstructive pulmonary diseases (COPD).

支气管气道的上皮细胞直接暴露于环境，是最先接触环境的细胞。 针对空气中颗粒物、过敏原和传染源的防线。过敏期间 气道炎症时，上皮既是介质产生的来源，也是介质产生的目标 重塑过程。因此，支气管上皮细胞不仅在维持 气道的物理化学稳态，而且也参与气道疾病的发病机制。然而， 对于介体、效应子和重塑基因的转录后调控知之甚少 炎症反应期间这些细胞中的表达。使用两个体外细胞模型和一个体内 过敏性气道炎症的体内小鼠模型，我们的初步研究支持以下模型： IL-4/TNF-α 刺激后，转录激活导致炎症介质大量涌入 mRNA 进入细胞质，其中 microRNA (miRNA) 介导的翻译抑制被释放， 全局翻译增加，P-体（用于存储和/或降解的细胞质结构域） 翻译抑制的 mRNA）被分解。这些协调一致的转录后活动有助于 细胞需要处理将炎症介质 mRNA 转化为蛋白质的快速需求。经过一个 持续暴露于 IL-4/TNF-α、HuR（一种富含 AU 元素 (ARE) 的结合蛋白）易位， 从细胞核到细胞质的过程是在活化的支气管上皮细胞中引起的。 HuR 然后是同事 细胞质中含有 ARE 的 mRNA 编码炎症介质，从而下调其炎症介质 翻译，从而抑制炎症反应。以下具体目标旨在 测试这个模型：1）阐明改变功能的分子和生化机制 miR-155 是一种与免疫密切相关的 miRNA，存在于活化的支气管上皮细胞中，并定义了 miR-155在调节支气管上皮细胞炎症介质基因表达中的作用； 2) 至 确定 P 体减少是否是支气管上皮细胞活化的标志以及如何减少 P-体组装和分解的改变影响支气管炎症反应 上皮细胞； 3) 确定HuR如何下调炎症介质的表达 激活的支气管上皮细胞中的 MCP-1 等分子以及如何改变 HuR 表达 支气管上皮调节过敏性气道炎症。拟议的研究将提供 对支气管上皮细胞转录后机制的重要认识 细胞调节其炎症反应，从而导致新治疗方法的开发 缓解与哮喘等慢性气道疾病相关的气道炎症的方法 和慢性阻塞性肺疾病（COPD）。