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

项目总结/摘要 白细胞介素-1（IL-1）在宿主防御结核分枝杆菌（Mtb）中起重要作用， 导致人类结核病的细菌。IL-1对结核分枝杆菌感染时的抗细菌免疫至关重要 小鼠感染和IL-1受体（IL-1 R1）信号传导的遗传多态性与更大的风险相关 活动性肺结核IL-1 R1由肺中的造血源性细胞和基质细胞表达， 但IL-1 R1信号在抗TB保护性免疫中的细胞类型特异性作用仍不清楚。 在NIAID的R56 Bridge资助的支持下，我们研究了不同肺细胞对IL-10的贡献。 1 R1介导的保护性免疫。我们使用骨髓嵌合体，发现IL-1 R1表达 对保护小鼠免受严重疾病至关重要。我们生成了一个敲入面板， 敲除小鼠品系，其中IL-1 R1表达在特定细胞中条件性缺失或恢复， 在野生型或IL-1 R1缺陷型宿主背景中。我们的初步结果表明，IL-1 R1的表达， 对II型肺泡上皮细胞（AECII）的作用对于控制细菌复制是必要的和充分的， 肺部炎症和预防消耗性疾病。AECII-内在IL-1 R1信号传导对于抗- 分枝杆菌免疫和预防I型IFN（IFN-I）依赖性中性粒细胞流入。中性粒细胞耗竭或 IFN-I显著降低细菌负荷，免疫病理学。此外，AECII限制了GM的过度生产， 肺中的CSF通过减少细菌负荷、体重、呼吸道感染和呼吸道感染来保护高度易感的GM-CSF缺陷动物。 损失和肺部病理学。重要的是，IFN-I阻断剂挽救了肺泡I型（AEC-I）和II型（AECII） 在进行性疾病期间受损的上皮细胞。根据初步结果，我们 假设AECII中的IL-1 R1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的完整性。我们 有三个具体目标。在aim 1中，我们将研究GM-CSF在调节抗微生物免疫中的作用。 通过检测从缺乏或表达 AECII中的IL-1 R1表达。在aim 2中，我们将研究AECII衍生的前列腺素E2（PGE 2）在 调节IFN-I应答和随后的致病性嗜中性粒细胞流入以防止组织损伤。最后在 aim 3，我们将研究IFN-Ⅰ对肺泡上皮细胞修复和再生的影响， 感染肺样品中肺上皮细胞的谱系追踪和空间分析。总体而言，完成 为IL-1 R1介导的保护性免疫提供了机制依据，并揭示了IL-1 R1介导的免疫保护机制。 靶向气道上皮细胞，用于增强抗微生物免疫和限制不可阻挡的肺损伤 在结核病期间引起的，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.