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

项目摘要/摘要 白介素1(IL-1)在机体对结核分枝杆菌(Mtb)的免疫防御中起着重要作用。 引起人类疾病结核病(TB)的细菌。IL-1在结核分枝杆菌感染过程中抗菌免疫中的作用 小鼠感染和IL-1受体(IL-1R1)信号的遗传多态与更大的风险相关 死于活动性肺结核。IL-1R1在肺的造血细胞和基质细胞中都有表达， 但IL-1R1信号在抗结核保护性免疫中的细胞类型特异性作用尚不清楚。 在NIAID R56桥拨款的支持下，我们研究了不同肺细胞对IL-2的贡献。 1R1介导的保护性免疫。我们使用了骨髓嵌合体，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的侵袭至关重要。我们生成了一组敲门砖和 敲除有条件地删除IL-1R1表达的小鼠品系，或者在特定细胞中恢复表达 在野生型或IL-1R1缺乏的宿主背景中。我们的初步结果表明，IL-1R1的表达 在II型肺泡上皮细胞(AECII)上培养对控制细菌复制既是必要的也是充分的， 肺部发炎，预防消瘦疾病。AECII内源性IL-1R1信号转导通路在抗AECII中的作用 分枝杆菌免疫与防止I型干扰素依赖中性粒细胞内流。耗尽中性粒细胞或 免疫病理显示，干扰素-I能显著降低细菌载量。此外，AECII限制了通用汽车的过剩生产- 肺内脑脊液通过减少细菌负荷、减轻体重来保护高度易感的GM-CSF缺陷动物 丢失和肺部病理改变。重要的是，干扰素-I阻断挽救了I型肺泡(AEC-I)和II型肺泡(AECII) 在进展性疾病过程中以其他方式受损的上皮细胞。根据我们的初步结果，我们 AECII中IL-1R1信号通过GM-CSF增强髓系细胞抗微生物功能的假设 产生并抑制病理水平的干扰素-I的产生，以维持上皮屏障的完整性。我们 有三个具体目标。在目标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的小鼠骨髓细胞中获得的细菌适合性和复制动力学 IL-1R1在AECII中的表达在AIM2中，我们将研究AECII衍生的前列腺素E2(PGE2)在 调节干扰素-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 AIM 3，我们将研究干扰素-I对肺泡上皮细胞修复和再生的影响 感染肺标本中肺上皮细胞的谱系追踪和空间分析。总体而言，完成 这些目的将为IL-1R1介导的保护性免疫提供机制基础，并揭示其作用机制 靶向呼吸道上皮细胞增强抗菌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的肺功能损害。

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.