Alveolar Macrophage Iron Overload in COPD Pathogenesis

项目总结 慢性阻塞性肺疾病(COPD)是一种与吸烟相关的呼吸系统疾病，是世界上第三大吸烟者。 全球范围内的死因。功能障碍的呼吸道和肺泡巨噬细胞数量增加。 (AM)在吸烟者和COPD患者的肺中，定位于损伤区域。尽管有这种联系，但 香烟烟雾(CS)如何引起AM功能障碍的机制，以及AM功能障碍如何促进AM功能障碍 小气道疾病和肺气肿是慢性阻塞性肺疾病的两个特征，人们对这两种疾病的发展知之甚少。 这项建议解决了知识中的这一关键差距，并测试了以下假设：慢性阻塞性肺疾病患者AM功能障碍 在机制上与这些细胞中异常的铁积累有关。使用多中心前瞻性COPD (SPIROMICS)队列中，我们先前发现在胚胎中铁和铁相关蛋白的水平增加。 吸烟者和临床预后不良的COPD患者的支气管肺泡灌洗液。AM是 这种肺细胞外铁的可能来源，因为吸烟者和COPD患者的AM是铁超载的 并在培养中释放铁。我们复制了AM铁蓄积和释放的临床现象 小鼠CS暴露模型。然后，我们使用单细胞RNA测序，发现了新的AM亚群 它们具有独特的铁相关基因表达特征，这与铁摄取增加是一致的。这些 “铁巨噬细胞”，我们称之为铁巨噬细胞，减少了相关基因的表达。 吞噬和免疫激活，提示这种CS诱导的AM铁蓄积可能具有 对AM的后果，以及可能对CS暴露的肺部的影响。我们将检验我们的假设，即联邦住房抵押贷款委员会或- 用我们的小鼠CS模型机械地和翻译地协调COPD患者的肺损伤发展 使用SPIROMICS队列。目标1将比较CS引起的小气道损伤和肺气肿的发展- 核受体辅活化子4(Ncoa4ΔCD11c)缺铁小鼠与对照组小鼠之间的关系 代谢缺陷，减轻CS引起的铁蓄积。AIM 2检测Ncoa4ΔCD11c和Ncoa4fl/fl 对照组小鼠在CS肺炎链球菌感染2次模型中，从而确定是否减少 AM铁负荷可减轻CS诱导的AM功能障碍，提高对病原体的反应性。目标3定义 慢性阻塞性肺疾病患者AM铁蓄积的临床意义及铁基因和AM表达的检测 铁含量可作为COPD严重程度的标志。该提案提出了一项五年职业发展计划， 建立在我以前研究的基础上，并整合了我的指导和咨询的不同专业领域 团队。它需要有针对性的培训计划，该计划针对与以下方面相关的特定领域的发展而量身定做 免疫学、巨噬细胞生物学、铁生物学和翻译研究，由物理和智能推动- 由威尔·康奈尔医学院的学术环境提供的教学资源。拟议中的实验， 教学培训以及指导团队将使我拥有一套独特的跨学科技能，这将 使我能够过渡到独立，成为一名内科科学家，研究肺和巨噬细胞生物学以及铁生物学。

PROJECT SUMMARY Chronic obstructive pulmonary disease (COPD) is a smoking-associated respiratory disease and is the 3rd lead- ing cause of death worldwide. There are increased numbers of dysfunctional airway and alveolar macrophages (AMs) in the lungs of smokers and COPD patients, localizing to areas of injury. Despite this connection, the mechanisms behind how cigarette smoke (CS) elicits AM dysfunction, and how AM dysfunction facilitates the development of small airways disease and emphysema, two defining features of COPD, are poorly understood. This proposal addresses this critical gap in knowledge and tests the hypothesis that AM dysfunction in COPD is mechanistically linked to abnormal iron accumulation in these cells. Using a multicenter prospective COPD (SPIROMICS) cohort, we previously associated increased levels of iron and iron-related proteins in the bron- choalveolar lavage fluid of smokers and COPD patients with adverse clinical COPD outcomes. AMs are the putative source for this lung extracellular iron, as AMs from smokers and COPD patients are iron-overloaded and release iron in culture. We replicated this clinical phenomenon of AM iron accumulation and release using a murine CS-exposure model. We then used single-cell RNA sequencing and discovered novel AM subsets which have a unique iron-related gene expression signature that is consistent with increased iron uptake. These “iron macrophages”, which we designate as FeMacs, have decreased expression of genes associated with phagocytosis and immune activation, suggesting that this CS-induced AM iron accumulation may have functional consequences for AMs, and potentially for the CS-exposed lung. We will test our hypothesis that FeMacs or- chestrate lung injury development in COPD both mechanistically using our murine CS model and translationally using the SPIROMICS cohort. Aim 1 will compare CS-induced small airways damage and emphysema develop- ment between control mice and mice with AMs deficient in nuclear receptor coactivator 4 (Ncoa4ΔCd11c), an iron metabolism defect which mitigates CS-induced iron accumulation. Aim 2 examines Ncoa4ΔCd11c and Ncoa4fl/fl control mice in a CS-Streptococcus pneumoniae infection 2-hit model, thereby determining whether reducing AM iron overload can alleviate CS-induced AM dysfunction and improve response to pathogen. Aim 3 defines the clinical relevance of AM iron accumulation in human COPD and tests AM expression of iron genes and AM iron content as markers of COPD severity. This proposal presents a five-year career development plan that builds on my previous research and integrates the different domains of expertise of my mentorship and advisory teams. It entails a targeted training plan that is tailored towards the development of specific areas related to immunology, macrophage biology, iron biology, and translational research, facilitated by the physical and intel- lectual resources provided by the academic environment at Weill Cornell Medicine. The proposed experiments, didactic training, as well as mentorship team will position me with a unique set of interdisciplinary skills that will enable my transition to independence as a physician-scientist in lung and macrophage biology and iron biology.