Mechanisms of lung macrophage programming by MUC5B during health and disease

MUC5B 在健康和疾病期间对肺巨噬细胞编程的机制

• 批准号: 9177013
• 负责人: Christopher M Evans
• 金额: $ 70.88万
• 依托单位: NATIONAL JEWISH HEALTH
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9177013
• 关键词: Acute; Alveolar Macrophages; Alveolus; Apoptosis; Attenuated; Back; Bacteria; Binding; Biological Assay; Breathing; Coughing; Dependence; Deposition; Development; Disease; Down-Regulation; Figs - dietary; Genetically Engineered Mouse; Glycoconjugates; Health; Homeostasis; Host Defense; Immunoglobulins; Infection; Inflammation; Inflammation Mediators; Inflammatory; Inflammatory Response; Injury; Knock-out; Knockout Mice; Laboratories; Lectin Receptors; Life; Ligands; Link; Lung; MUC5B gene; Measurement; Mediating; Modeling; Molecular; Mucins; Mucociliary Clearance; Mucous body substance; Mus; Physiological; Pneumonia; Polysaccharides; Prevention; Production; RNA Interference; Recruitment Activity; Regulation; Resolution; Rest; Role; Sialic Acids; Signal Transduction; Staphylococcus aureus; Stimulus; Testing; Time; glycosylation; in vivo; inflammatory lung disease; macrophage; monocyte; mouse model; novel; particle; pathogen; programs; restoration; selective expression; sialic acid binding Ig-like lectin

PROJECT SUMMARY Each day, the lungs are exposed to billions of particles whose accumulation can potentially cause infection and damage. While it is crucial to defend against these exposures, it is equally important that protection occurs with minimal physiological disruption or injury caused by inflammation. Mucus and macrophage clearance are hallmark non-inflammatory defenses. Particles and pathogens that deposit in the airways are trapped in mucus and eliminated by ciliary and cough forces, while those in alveoli are ingested by alveolar macrophages (AMs). Using Muc5b knockout mice, we previously showed that Muc5b is required for effective mucociliary clearance and for maintaining healthy pools of resident AMs. The primary objective of this proposal is to determine specific mechanisms by which Muc5b regulates AM function during homeostasis and during acute and resolving inflammation. We have identified a novel mechanism that directly links Muc5b to AM function via sialic acid-binding immunoglobulin-type lectin receptor-F (Siglec-F), an inhibitory immunoreceptor that is expressed selectively by resident AMs and is known to bind α2,3-linked sialic acid-containing glycoconjugates. Muc5b is α2,3-sialylated and is an endogenous Siglec-F ligand. We propose that stimulation of Siglec-F by Muc5b calibrates AM inflammatory responses in the resting lung. Thus, in healthy states, the ability of resident AMs to serve protective roles while simultaneously limiting potentially injurious inflammatory responses may occur by a homeostatic programming mechanism mediated by stimulation of Siglec-F by Muc5b. When homeostasis is disrupted by stimuli such as bacteria, a temporary induction of AM inflammatory responsiveness is required. Furthermore, resident AMs are joined by recruited macrophages that arise from circulating monocytes. These recruited monocyte-derived AMs (MDAMs) lack Siglec-F and are highly pro- inflammatory. At the same time that MDAMs are recruited, resident AMs down-regulate their Siglec-F expression and become pro-inflammatory. As inflammation resolves, recruited MDAMs undergo apoptosis and are eliminated, whereas resident AMs restore Siglec-F expression and return to their non-inflammatory states. We postulate that transient reduction of MUC5B:Siglec-F signaling permits an inflammatory response and that restoration of MUC5B:Siglec F signaling is required for its resolution. We hypothesize that stimulation of Siglec-F by Muc5b is a major mechanism for controlling macrophage inflammatory responses during homeostasis and inflammation. We will use wild type and genetically engineered mice, models of acute inflammation, and immunological readouts to test this hypothesis in the following three Specific Aims: 1. Test the hypothesis that during homeostasis, protective AM activities are maintained by MUC5B sialyl glycan- dependent Siglec-F stimulation. 2. Test the hypothesis that MUC5B:Siglec-F dependent inhibitory mechanisms are lost during acute inflammation. 3. Test the hypothesis that re-engagement of MUC5B with Siglec-F on AMs drives the resolution of inflammation.

项目摘要 每天，肺暴露于数十亿个颗粒，其积累可能会引起感染和 损害。尽管防御这些暴露至关重要，但保护同样重要的是 最小的身体干扰或受伤引起的伤害。粘液和巨噬细胞清除是 标志性非炎症防御。沉积在气道中的颗粒和病原体被困在粘液中 并被睫状体和咳嗽力消除，而肺泡的肺泡巨噬细胞（AMS）摄入了肺泡的力。 使用MUC5B敲除小鼠，我们先前表明MUC5B有效地清除需要MUC5B 并保持健康的居民AM池。该提议的主要目的是确定 MUC5B在稳态期间和急性期间调节AM功能的特定机制 解决炎症。我们已经确定了一种新型机制，该机制将MUC5B直接连接到AM功能 唾液酸结合免疫球蛋白型杠杆受体F（SIGLEC-F），一种抑制性免疫受体，是 由居民AM选择性地表达，并已知可以结合含有α2,3连接的含有唾液酸的糖结合物。 MUC5B为α2,3-磷酸化，是内源性Siglec-F配体。我们建议通过 MUC5B校准静息肺中的AM炎症反应。在健康状态下，居民的能力 AM可以担任受保护的角色，同时限制潜在的伤害性炎症反应 通过MUC5B刺激SIGLEC-F介导的稳态编程机制。什么时候 稳态受到细菌等刺激的破坏，暂时诱导AM炎症 需要响应能力。此外，居民AM由招募的巨噬细胞加入 循环单核细胞。这些招募的单核细胞衍生的AMS（MDAMS）缺乏Siglec-F，并且高度支持 炎症。同时招募了MDAM，居民AMS下调了他们的Siglec-f 表达并成为促炎症。随着炎症的消退，招募的MDAMS经历了凋亡和 被消除，而居民AMS恢复了Siglec-F的表达并返回其非炎症状态。 我们假设MUC5B的短暂降低：SigleC-F信号传导允许炎症反应，并且 MUC5B的恢复：Siglec F信号的分辨率是必需的。我们假设刺激 MUC5B的SIGLEC-F是控制巨噬细胞炎症反应的主要机制 稳态和炎症。我们将使用野生型和基因工程的小鼠，急性模型 在以下三个特定目的中，炎症和免疫学读数以检验该假设：1。 在体内稳态期间，受保护的AM活性在MUC5B siAllyl Glycan-维持的假设 依赖的siglec-f刺激。 2。测试MUC5B：SIGLEC-F依赖性抑制的假设 急性炎症期间的机制丢失。 3。检验以下假设：MUC5B与 AMS上的Siglec-F驱动炎症的分辨率。