MECHANISM AND FUNCTION OF LET-7, A NOVEL MODULATOR OF TH17-DEPENDENT EMPHYSEMA

TH17 依赖性肺气肿的新型调节剂 Let-7 的机制和功能

基本信息

批准号：
10470262
负责人：
DAVID B CORRY
金额：
$ 40.15万
依托单位：
BAYLOR COLLEGE OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-01 至 2023-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10470262
关键词：
Accounting Air Pollution Anti-Inflammatory Agents Apoptosis Autoimmune CD4 Positive T Lymphocytes CD86 gene Carbon Black Cell Differentiation process Cells Chronic Obstructive Pulmonary Disease Dendritic Cells Development Down-Regulation Equilibrium Exercise FOXO1A gene Family Gene Expression Genes Goals Histone Deacetylase Homeostasis Human Hypercapnia IL6 gene Immune Immune response Inflammation Inflammatory Inhalation Innate Immune Response Interleukin-10 Knock-out Knockout Mice Lead LoxP-flanked allele Lung Mediating Mediator of activation protein Messenger RNA Methods MicroRNAs Modeling Molecular Molecular Analysis Morbidity - disease rate Mus Myelogenous Pathologic Phenotype Pulmonary Emphysema Pulmonary Inflammation Role Severities Smoke Smoker Stress T-Lymphocyte Testing Therapeutic Tobacco Transgenic Mice Up-Regulation Wild Type Mouse Work autoreactivity base cigarette smoke cytokine genome-wide global health macrophage member mortality mouse model nanosized novel therapeutic intervention overexpression particle response tool transcriptome

项目摘要

Chronic obstructive pulmonary disease (COPD) is a major rising global health threat in the 21st century. Emphysema, a progressive and destructive autoimmune endotype of COPD that often presents with hypercapnia and exercise limitation, is associated with significant morbidity and mortality. Like the well- established noxious effects of cigarette smoke (CS), we have demonstrated that nano-sized carbon black (nCB) particles, generated by incomplete combustion of tobacco, can cause emphysema. The mechanism for nCB or CS-mediated emphysema development includes activation of lung myeloid dendritic cells (mDCs) that promote differentiation of autoreactive T helper 1 (TH1), TH17 cells and reduced inducible regulatory T (iTreg) cells in the lungs. We have found that let-7 miRNAs are the dominant miRNAs expressed in mouse and human lung and immune cells. This and other preliminary findings suggest that let-7 members critically determine (i.e., “threshold”) distinct subsets of target genes depending on their aggregate expression levels. Our central hypothesis states that in response to CS, let-7 loci cooperate to modulate emphysema and orchestrate activation of mDCs and TH17 cells by thresholding target gene expression. We will test our hypothesis through the following Specific Aims: 1. Elucidate the intrinsic requirement of the let-7bc and let-7afd clusters in activation of acquired immune responses in experimental emphysema. Hypothesis: The let-7bc and let-7afd clusters work in tandem to generate thresholds in target gene expression in CD4+ T cells and orchestrate homeostatic TH17/iTreg balance, lung inflammation, and emphysema. We will perform comprehensive histopathological and cellular studies of let-7bc- and let-7afd-deficient mice to determine the let-7 mechanism of action after nCB or CS treatment. We will further identify target genes that potentially suppress (IL10, Foxo1) or enhance (Stat3, and RORγt) inflammation and emphysema expression. 2. Determine the role of let-7afd cluster on innate immune responses in emphysema. Hypothesis: Let-7 serves to temper molecular programming of TH17 driven emphysema acting in part in mDCs. Histopathological and molecular analysis of conditional (let-7 floxed mice) and global cluster knockouts, and let-7 transgenic mice will allow us to interrogate the mechanism(s) by which let-7 modulates TH17/iTreg homeostasis, apoptosis, and proliferation. 3. Determine the role of Let-7afd cluster in human emphysema. Hypothesis: Coordinate downregulation of Let- 7afd cluster in emphysematous lung mDCs promotes TH17 inflammation and upregulation of pro-inflammatory and co-stimulatory target genes. We will discern the pathophysiological consequence of reduced Let-7afd expression and overall Let-7 activity in the control of human lung mDC-mediated activation (e.g., induction of CD86, IL6) that is necessary for TH17 cell differentiation. We will also examine the role of Let-7afd overexpression using emphysematous human mDCs as a pilot strategy to inhibit TH17 inflammation.

慢性阻塞性肺疾病 (COPD) 是 21 世纪日益严重的全球健康威胁。肺气肿是 COPD 的一种进行性和破坏性自身免疫内型，通常表现为高碳酸血症和运动限制与显着的发病率和死亡率相关。确定了香烟烟雾（CS）的有害影响，我们已经证明纳米炭黑烟草不完全燃烧产生的（nCB）颗粒可引起肺气肿。 nCB 或 CS 介导的肺气肿发展包括肺髓样树突状细胞 (mDC) 的激活，促进自身反应性 T 辅助细胞 1 (TH1)、TH17 细胞的分化并减少诱导性调节性 T (iTreg) 我们发现let-7 miRNA 是小鼠和人类中表达的主要miRNA。这一结果和其他初步结果表明，let-7 成员批判性地确定（即， “阈值”）目标基因的不同子集取决于它们的聚合表达水平。假设指出，为了响应 CS，let-7 位点合作调节肺气肿并协调通过设定靶基因表达阈值来激活 mDC 和 TH17 细胞我们将通过以下方式验证我们的假设。具体目标如下： 1. 阐明 let-7bc 和 let-7afd 集群的内在要求实验性肺气肿中获得性免疫反应的激活假设：let-7bc 和 let-7afd。集群协同工作以生成 CD4+ T 细胞中目标基因表达的阈值并协调稳态 TH17/iTreg 平衡、肺部炎症和肺气肿我们将进行全面的检查。对 let-7bc 和 let-7afd 缺陷小鼠进行组织病理学和细胞研究，以确定 let-7 机制我们将进一步确定可能抑制的靶基因（IL10、Foxo1）。或增强（Stat3 和 RORγt）炎症和肺气肿表达 2. 确定 let-7afd 的作用。集中于肺气肿的先天免疫反应假设：Let-7 起到调节分子作用。 TH17 驱动的肺气肿的编程部分作用于 mDC 的组织病理学和分子分析。条件（let-7 floxed 小鼠）和全局簇敲除，let-7 转基因小鼠将使我们能够探究 let-7 调节 TH17/iTreg 稳态、细胞凋亡和增殖的机制。 3.确定Let-7afd簇在人类肺气肿中的作用假设：协调Let-的下调。肺气肿肺 mDC 中的 7afd 簇促进 TH17 炎症和促炎细胞的上调我们将辨别 Let-7afd 减少的病理生理学后果。控制人肺 mDC 介导的激活（例如，诱导 TH17 细胞分化所必需的 CD86、IL6）我们还将检查 Let-7afd 的作用。使用肺气肿人 mDC 过度表达作为抑制 TH17 炎症的试点策略。