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

• 批准号: 10001079
• 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
• 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/10001079
• 关键词: Accounting; Air Pollution; Anti-Inflammatory Agents; Apoptosis; Autoimmune Process; CD4 Positive T Lymphocytes; CD86 gene; Carbon Black; Cell Differentiation process; Cells; Chronic Obstructive Airway 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; Lung Inflammation; Mediating; Mediator of activation protein; Messenger RNA; Methods; MicroRNAs; Modeling; Molecular; Molecular Analysis; Morbidity - disease rate; Mus; Myelogenous; Pathologic; Phenotype; Pulmonary Emphysema; 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

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世纪全球健康威胁的主要增长。 肺气肿是COPD的进步和破坏性的自身免疫性内型，通常呈现 高碳酸盐和运动限制与明显的发病率和死亡率有关。像 我们已经证明了香烟烟雾（CS）的有害影响，我们已经证明了纳米大小的碳黑色 （NCB）通过不完全组合烟草产生的颗粒会导致肺气肿。机制 NCB或CS介导的肺气肿发育包括激活肺髓样树突状细胞（MDC） 促进自动反应性T辅助辅助器1（Th1），Th17细胞的分化，并降低了诱导型调节t（ITREG） 肺中的细胞。我们发现let-7 miRNA是在小鼠和人类中表达的主要miRNA 肺和免疫核管。这一和其他初步发现表明，Let-7成员批判性确定（即 “阈值”）靶基因的不同子集取决于其总表达水平。我们的中心 假设指出，在响应CS，Let-7基因座合作以调节肺气肿和编排 通过阈值靶基因表达激活MDC和Th17细胞。我们将通过 以下特定目的：1。阐明在 在实验性肺气肿中获得的免疫回报的激活。假设：Let-7BC和Let-7AFD 群集在CD4+ T细胞中的靶基因表达中产生阈值并进行编排 稳态TH17/ITREG平衡，肺注射和肺气肿。我们将执行全面 LET-7BC-和LET-7AFD缺乏小鼠的组织病理学和细胞研究以确定Let-7机制 NCB或CS处理后的作用。我们将进一步确定可能抑制的靶基因（IL10，FOXO1） 或增强（STAT3和RORγT）注射和肺气肿表达。 2。确定let-7afd的作用 肺气肿的先天免疫反应集群。假设：let-7用于温度分子 Th17驱动的肺气肿的编程部分作用于MDC。组织病理学和分子分析 有条件的（Let-7 Floxed小鼠）和全球簇敲除，Let-7转基因小鼠将使我们能够 询问Let-7调节Th17/ITREG稳态，凋亡和增殖的机制。 3。确定let-7afd簇在人肺气肿中的作用。假设：协调let的下调 7AFD簇中的肺部肺MDC促进了Th17注射和促炎的上调 和共刺激靶基因。我们将辨别降低7AFD的病理生理后果 在控制人肺MDC介导的激活中的表达和总let-7活性（例如，诱导 CD86，IL6）是Th17细胞分化所必需的。我们还将检查let-7afd的作用 使用过滤的人MDC作为抑制Th17注射的试验策略的过表达。