Type II alveolar epithelial cell-intrinsic IL-1 response in protective immunity against tuberculosis

项目概要/摘要 白细胞介素-1 (IL-1) 在宿主防御结核分枝杆菌 (Mtb) 过程中发挥着重要作用。 导致人类疾病结核病 (TB) 的细菌。 IL-1 对于 Mtb 期间的抗菌免疫至关重要 小鼠感染和 IL-1 受体 (IL-1R1) 信号基因多态性与更大的风险相关 from active pulmonary TB. IL-1R1 由肺中的造血源细胞和基质细胞表达， 但 IL-1R1 信号在针对结核病的保护性免疫中的细胞类型特异性作用仍不清楚。 在 NIAID R56 Bridge 资助的支持下，我们研究了不同肺细胞对 IL- 1R1 mediated protective immunity.我们使用骨髓嵌合体并发现IL-1R1表达 对基质细胞的影响对于保护小鼠免受严重疾病至关重要。 We generated a panel of knock-in and 敲除 IL-1R1 表达被条件性删除或在特定细胞中恢复的小鼠品系 在野生型或 IL-1R1 缺陷宿主背景下。我们的初步结果表明IL-1R1的表达 II型肺泡上皮细胞（AECII）对于控制细菌复制来说是必要且充分的， 肺部炎症并预防消耗性疾病。 AECII 固有的 IL-1R1 信号传导对于抗- 分枝杆菌免疫和预防 I 型干扰素 (IFN-I) 依赖性中性粒细胞流入。耗尽中性粒细胞或 IFN-I显着降低细菌负荷、免疫病理学。 Moreover, AECII-restricted overproduction of GM- 肺部的 CSF 通过减少细菌负荷和体重来保护高度易感 GM-CSF 缺陷的动物 损失和肺部病理学。重要的是，IFN-I 阻断可挽救 I 型 (AEC-I) 和 II 型 (AECII) 肺泡 在进行性疾病期间受损的上皮细胞。 Based on our preliminary results, we 假设 AECII 中的 IL-1R1 信号传导通过 GM-CSF 增强骨髓细胞的抗微生物功能 产生并抑制 IFN-I 产生的病理水平，以维持上皮屏障完整性。我们 have three specific aims.在目标1中，我们将研究GM-CSF在调节抗菌免疫中的作用 通过检查从缺乏或表达的小鼠获得的骨髓细胞中的细菌适应性和复制动态 IL-1R1 expression in AECII.在 Target2 中，我们将研究 AECII 衍生的前列腺素 E2 (PGE2) 在 调节 IFN-I 反应和随后的致病性中性粒细胞流入，以防止组织损伤。最后，在 目标3，我们将通过执行以下实验来研究IFN-I对肺泡上皮细胞修复和再生的影响 受感染肺样本中肺上皮细胞的谱系追踪和空间分析。总体来说，完成度 这些目标将为 IL-1R1 介导的保护性免疫提供机制基础，并揭示原理 靶向气道上皮细胞，增强抗菌免疫力并限制不可避免的肺部损伤 结核病期间引起的，即使在抗生素治疗后也会导致患者肺功能受损。

PROJECT SUMMARY/ABSTRACT Interleukin-1 (IL-1) plays an important role in the host defense against Mycobacterium tuberculosis (Mtb), the bacterium that causes human disease tuberculosis (TB). IL-1 is essential for anti-bacterial immunity during Mtb infection in mice and genetic polymorphisms in IL-1 receptor (IL-1R1) signaling are associated with greater risk from active pulmonary TB. IL-1R1 is expressed by both the hematopoietic-derived and stromal cells in the lung, but the cell-type specific roles of IL-1R1-signaling in protective immunity against TB remains unclear. Supported by a R56 Bridge grant from NIAID, we investigated the contribution of different lung cells to the IL- 1R1 mediated protective immunity. We used bone marrow chimaeras and discovered that IL-1R1 expression on stromal cells is crucial for protecting mice against severe disease. We generated a panel of knock-in and knock out mouse strains where IL-1R1 expression is conditionally deleted- or restored in specific cells either in a wild type or IL-1R1-deficient host background. Our preliminary results indicated that expression of IL-1R1 on type II alveolar epithelial cells (AECII) is both necessary and sufficient for controlling bacterial replication, inflammation in the lung and preventing wasting disease. AECII-intrinsic IL-1R1 signaling is critical for anti- mycobacterial immunity and preventing type I IFN (IFN-I) dependent neutrophil influx. Depleting neutrophils or IFN-I significantly reduced bacterial load, immunopathology. Moreover, AECII-restricted overproduction of GM- CSF in the lung protected the highly susceptible GM-CSF deficient animals by reducing bacterial load, weight loss and lung pathology. Importantly, IFN-I blockade rescued alveolar type I (AEC-I) and type II (AECII) epithelial cells that were otherwise damaged during progressive disease. Based on our preliminary results, we hypothesize that IL-1R1 signaling in AECII potentiates the anti-microbial function of myeloid cells by GM-CSF production and restrains the pathological level of IFN-I production to maintain epithelial barrier integrity. We have three specific aims. In aim1, we will investigate the role of GM-CSF in regulating antimicrobial immunity by examining bacterial fitness and replication dynamics in myeloid cells obtained from mice that lack or express IL-1R1 expression in AECII. In aim2, we will investigate the role of AECII-derived prostaglandin E2 (PGE2) in regulating IFN-I response and consequent pathogenic neutrophil influx to prevent tissue damage. Finally, in aim3, we will investigate the impact of IFN-I on alveolar epithelial cell repair and regeneration by performing lineage tracing and spatial analysis of lung epithelial cells in the infected lung samples. Overall, the completion of these aims will provide mechanistic basis for IL-1R1 mediated protective immunity and reveal principles to target airway epithelial cells for boosting antimicrobial immunity and limiting the inexorable lung damage caused during TB that contributes to lung function impairment in patients even after antibiotic therapy.