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: 9750783
• 负责人: Christopher M Evans
• 金额: $ 63.88万
• 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 2022-05-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9750783
• 关键词: Acute; Alveolar Macrophages; Apoptosis; Attenuated; Back; Bacteria; Binding; Biological Assay; Coughing; Dependence; Deposition; Development; Disease; Down-Regulation; Exposure to; Genetically Engineered Mouse; Glycoconjugates; Health; Homeostasis; Host Defense; Immunoglobulins; Immunologics; Infection; Inflammation; Inflammation Mediators; Inflammatory; Inflammatory Response; Ingestion; Inhalation; Injury; Knock-out; Knockout Mice; Laboratories; Lectin Receptors; Ligands; Link; Lung; MUC5B gene; Measurement; Mediating; Modeling; Molecular; Mucins; Mucociliary Clearance; Mucous body substance; Mus; Physiological; Pneumonia; Polysaccharides; Prevention; Production; RNA Interference; Regulation; Resolution; Rest; Role; Sialic Acids; Signal Transduction; Staphylococcus aureus; Stimulus; Testing; Time; glycosylation; in vivo; inflammatory lung disease; macrophage; monocyte; novel; particle; pathogen; programs; recruit; 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.

项目总结 每天，肺部暴露在数十亿个颗粒中，这些颗粒的积累可能会导致感染和 损坏。虽然防御这些暴露是至关重要的，但同样重要的是，保护发生在 由炎症引起的最小的生理干扰或损伤。粘液和巨噬细胞的清除 标志着非炎症性防御。沉积在呼吸道中的颗粒和病原体被困在粘液中 并被纤毛和咳嗽力量消除，而肺泡内的那些被肺泡巨噬细胞(AM)摄取。 使用MUC5B基因敲除小鼠，我们之前证明了MUC5B是有效的粘液纤毛清除所必需的 以及维持健康的常驻AM池。这项提案的主要目标是确定 MUC5B在动态平衡和急性期调节AM功能的具体机制 消炎解毒。我们已经确定了一种新的机制，它通过以下方式直接将MUC5B与AM功能联系起来 唾液酸结合免疫球蛋白型凝集素受体F(Siglec-F)，是一种抑制性免疫受体，是 由驻留的AM选择性表达，并已知与α2，3-连接的含唾液酸的糖共轭结合。 MUC5B是α2，3-唾液酸化，是一种内源性Siglec-F配体。我们认为，通过刺激Siglec-F MUC5B可校准静息肺中AM的炎症反应。因此，在健康状态下，居民的能力 AM在发挥保护作用的同时限制潜在的破坏性炎症反应可能 通过由MUC5B刺激Siglec-F介导的动态平衡编程机制发生。什么时候 动态平衡被细菌等刺激物破坏，这是AM炎症的暂时诱导 响应性是必需的。此外，常驻AM由新生的巨噬细胞加入，这些巨噬细胞 循环中的单核细胞。这些招募的单核细胞来源的AM(MDAM)缺乏Siglec-F，并且高度促进 煽动性的。在招募MDAM的同时，常驻AM下调了他们的Siglec-F 表达，并变得促炎。随着炎症的消退，招募的MDAM经历细胞凋亡和 被消除，而常驻AM恢复Siglec-F的表达，并返回到其非炎症状态。 我们假设，MUC5B：Siglec-F信号的一过性降低允许炎症反应，并且 MUC5B的恢复：需要Siglec F信令来解决它。我们假设这种刺激 MUC5B Siglec-F是控制巨噬细胞炎症反应的主要机制 动态平衡和炎症。我们将使用野生型和转基因小鼠，急性胰腺炎模型 炎症和免疫学读数在以下三个具体目标中验证这一假说：1.测试 假设在动态平衡期间，保护性AM活性是由MUC5B唾液酸葡聚糖- 依赖Siglec-F刺激。2.检验MUC5B：Siglec-F依赖抑制作用的假设 在急性炎症期间，机制会消失。3.检验以下假设：MUC5B与 AM上的Siglec-F可促进炎症的消退。