NLRX1 and MAVS in cigarette smoke-induced inflammation and alveolar remodeling

描述（由申请人提供）：慢性阻塞性肺疾病（COPD）包括几种临床综合征，最明显的是肺气肿和慢性支气管炎。在美国和世界范围内，这是一个主要的未满足的医疗需求，在西方社会，它与香烟烟雾（CS）暴露密切相关。我们假设CS异常调节RLH信号，RLH信号异常在CS诱导的炎症和重塑反应中起重要作用。为了解决这个问题，我们重点研究了调控MAVS的分子，特别是线粒体分子，因为MAVS与线粒体外膜结合，其在线粒体上的定位对MAVS的正常功能至关重要。有趣的是，我们对cs诱导的小鼠肺气肿模型的初步研究表明，一种新的线粒体分子、核苷酸结合域和富含亮氨酸的重复序列蛋白X1 （NLRX1）与MAVS相互作用，抑制MAVS介导的I型干扰素（ifn）和NF？B信号在cs暴露的肺中被显著抑制。此外，cs诱导炎性小体(s)的显著激活以及随之而来的白细胞介素1β (IL1β)和IL18的激活，诱导I型ifn和肺部炎症和肺气肿破坏；这些反应在NLRX1缺失时被夸大，而在MAVS缺失时得到改善。重要的是，NLRX1的表达在三个不同的人类COPD队列的肺中受到抑制。此外，这种抑制表现出与气流受限程度（COPD的标志）以及与疾病严重程度相关的其他临床变量的显著相关性。这一系列的发现使我们得出以下多部分假设和具体目标；目标# 1。明确MAVS和NLRX1在cs诱导的炎性小体激活、I型ifn的诱导以及肺部炎症和重塑反应中的作用；目标# 2。表征CS对小鼠NLRX1表达的影响，COPD患者NLRX1表达的改变，以及NLRX1在巨噬细胞炎性小体活化中的作用；目标# 3。体外测定NLRX1对巨噬细胞MAVS炎性体复合物组装的活性氧依赖性抑制作用目标# 4。确定在体内恢复NLRX1是否能改善cs诱导的炎性小体激活、I型ifn的诱导以及肺部炎症和重塑反应。随着这个项目的成功完成，我们将确定新的线粒体分子NLRX1和MAVS在COPD发展中的作用。此外，我们将测试恢复被抑制NLRX1或调节该通路的干预措施的可能性，这些干预措施可能具有改善吸烟者和COPD患者肺功能快速下降以及肺部炎症增强的治疗潜力。

DESCRIPTION (provided by applicant): Chronic obstructive pulmonary disease (COPD) encompasses several clinical syndromes, most notably emphysema and chronic bronchitis. It is a major unmet medical need in the United States and worldwide and, in western society, is impressively associated with cigarette smoke (CS) exposure. We hypothesized that CS dysregulates RLH signaling, and the dysregulation of RLH signaling plays an important role in CS-induced inflammation and remodeling responses. To address this, we focused additional investigations on the molecules that regulate MAVS, especially mitochondrial molecules, because MAVS is bound to the mitochondrial outer membrane and its localization on mitochondria is critical for the proper functioning of MAVS. Intriguingly, our preliminary studies from our CS-induced murine emphysema model revealed that a novel mitochondrial molecule, nucleotide binding domain and leucine rich repeat containing protein X1 (NLRX1) that interacts with MAVS and inhibits MAVS-mediated production of type I interferons (IFNs) and NF?B signaling, was significantly suppressed in CS-exposed lungs. In addition, CS-induced significant activation of inflammasome(s) and the consequent interleukin1β (IL1β) and IL18 activation, induction of type I IFNs and pulmonary inflammation and emphysematous destruction; these responses were exaggerated in the absence of NLRX1, while ameliorated in the absence of MAVS. Importantly, the expression of NLRX1 is suppressed in lungs from three different human COPD cohorts. Furthermore, this suppression shows impressive correlation with the degree of airflow limitation, a hallmark of COPD, and other clinical variables related to disease severity. This constellation of findings has led us to the following multipart hypothesis and specific aims; Aim #1. Define the roles of MAVS and NLRX1 in CS-induced activation of inflammasome(s), induction of type I IFNs and pulmonary inflammatory and remodeling responses; Aim #2. Characterize the effects of CS on the expression of NLRX1 in mice, the alteration of the expression of NLRX1 in patients with COPD, and the role of NLRX1 in the inflammasome activation in macrophages; Aim #3. Determine the reactive oxygen species (ROS)dependent inhibition of NLRX1 against the assembly of inflammasome complex on MAVS in macrophages in vitro; Aim #4. Determine if restoring NLRX1 in vivo ameliorates CS-induced activation of inflammasome(s), induction of type I IFNs and pulmonary inflammatory and remodeling responses. With successful accomplishment of this project, we will define the roles of novel mitochondrial molecules called NLRX1 and MAVS in the development of COPD. In addition, we will test the possibility that interventions that restore suppressed NLRX1 or modulate this pathway may have therapeutic potential to ameliorate rapid decline of lung function as well as enhanced pulmonary inflammation in smokers and patients with COPD.