Alternative macrophage activation in acute Pseudomonas pneumonia

描述（由申请人提供）：替代性巨噬细胞活化调节对病原生物体的炎症反应。迄今为止，大多数工作都描述了它们在Th 2型免疫应答中的作用。已显示替代活化的巨噬细胞（AAM）抑制经典活化的巨噬细胞增殖和功能，以及通过产生II型细胞因子转化生长因子（TGF）-β和β-D-1抑制T细胞介导的免疫应答。虽然主要功能是协调重塑和修复机制，但TGF-β 1和TGF-β 1在控制肺内稳态和抑制炎症方面也很重要。AAM在调节肺部细胞外革兰氏阴性细菌感染的炎症反应中的功能尚未被表征。了解AAM在这种情况下的作用对于促进我们对影响囊性纤维化（CF）和其他慢性肺部炎症患者的免疫机制的理解至关重要。CF导致进行性的、危及生命的肺损伤，这在很大程度上是由于对铜绿假单胞菌感染的反复的、失调的炎症反应。因此，这项工作将解决的假设， 巨噬细胞减少铜绿假单胞菌感染中的肺部炎症，并且这依赖于TGF β和β-内酰胺酶-1的产生。我们将利用正常和基因工程小鼠的铜绿假单胞菌肺炎模型来解决3个不同的目标。目的1将确定铜绿假单胞菌肺部感染引起的炎症调节是否依赖于替代性巨噬细胞活化。目的2将解决是否AAM调节T细胞的处置可以控制炎症和肺损伤，通过生产TGF？。目的3将确定巨噬细胞是否需要表达β-内酰胺酶-1来预防铜绿假单胞菌肺炎诱导的炎症。将使用具有遗传改变的AAM、TGF β信号传导和巨噬细胞特异性β-内酰胺酶-1产生的小鼠模型，沿着过继转移方法和补充的体外实验。这些改变的影响将在炎症、经典巨噬细胞功能和T细胞亚群活化和功能方面进行评价，以确定巨噬细胞在调节这些反应中采用的重要机制。突出的临床相关性，这项工作是使用抗菌剂阿奇霉素作为免疫调节剂的CF患者。该药物已被证明可以减缓肺功能下降，降低假单胞菌感染的CF患者的发病率，但其有益的机制尚不清楚。最近，在体外和动物研究中均显示，阿奇霉素使巨噬细胞极化为替代样表型，显著增加了巨噬细胞酶-1的表达。这些数据，沿着阿奇霉素在CF患者中的成功长期使用，使得研究替代性巨噬细胞活化在响应假单胞菌肺炎中的作用具有吸引力，并且可能产生用于干预以改变这种破坏性的炎症和气道损伤循环的新的治疗靶点。 公共卫生相关性：囊性纤维化和其他慢性肺部疾病导致进行性的、危及生命的肺破坏，部分原因是过度炎症，反复细菌感染导致频繁加重。该项目将研究巨噬细胞在对铜绿假单胞菌的免疫应答中发挥的调节作用，铜绿假单胞菌是这些患者中最常见的细菌病原体之一。这项工作将导致确定干预的治疗靶点，以延缓这些患者的肺功能下降速度。

DESCRIPTION (provided by applicant): Alternative macrophage activation regulates inflammatory responses to pathogenic organisms. Most work to date has characterized their role in Th2-type immune responses. Alternatively activated macrophages (AAM) have been shown to inhibit classically activated macrophage proliferation and function, as well as to suppress T cell mediated immune responses through the production of the type II cytokine transforming growth factor (TGF)-¿ and arginase-1. While primarily functioning to orchestrate remodeling and repair mechanisms, arginase-1 and TGF¿ are also important in controlling lung homeostasis and suppressing inflammation. The function of AAM in regulating the inflammatory response to extracellular Gram-negative bacterial infection in the lungs has not been characterized. Understanding the role of AAM in this setting is critical for advancing our understanding of immune mechanisms affecting patients with cystic fibrosis (CF) and other chronic pulmonary inflammatory conditions. CF causes progressive, life-threatening lung damage due in large part to repeated, dysregulated inflammatory responses to Pseudomonas aeruginosa infection. Therefore, this work will address the hypothesis that alternatively activated macrophages decrease pulmonary inflammation in P. aeruginosa infection, and that this is dependent upon production of TGF¿ and arginase-1. We will utilize a model of P. aeruginosa pneumonia in normal and genetically engineered mice to address 3 distinct aims. Aim 1 will determine whether regulation of inflammation caused by P. aeruginosa lung infection is dependent upon alternative macrophage activation. Aim 2 will address whether AAM regulation of T cell disposition can control inflammation and lung damage through the production of TGF¿. Aim 3 will determine whether arginase-1 expression by macrophages is required to prevent inflammation induced by P. aeruginosa pneumonia. Mouse models with genetically altered AAM, TGF¿ signaling, and macrophage-specific arginase-1 production will be used, along with adoptive transfer methodologies and complementary in vitro experiments. The impact of these alterations will be evaluated in terms of inflammation, classical macrophage function, and T cell subset activation and function to determine the important mechanisms employed by macrophages in regulating these responses. Highlighting the clinical relevance of this work is the use of the antimicrobial agent azithromycin as an immunomodulator in patients with CF. This drug has been shown to slow pulmonary function decline and decrease morbidity in CF patients infected with Pseudomonas, but the beneficial mechanistic effect is unknown. Recently it has been shown, in both in vitro and animal studies, that azithromycin polarizes macrophages to an alternative-like phenotype, dramatically increasing the expression of arginase-1. This data, along with the successful long-term use of azithromycin in patients with CF, make studying the role of alternative macrophage activation in response to Pseudomonas pneumonia attractive and likely to yield novel therapeutic targets for intervention to alter this destructive cycle of inflammation and airway damage. PUBLIC HEALTH RELEVANCE: Cystic fibrosis and other chronic lung diseases cause progressive, life-threatening lung destruction due in part to excessive inflammation with frequent exacerbations caused by repeated bacterial infections. This project will investigate the regulatory role that macrophages play in the immune response to Pseudomonas aeruginosa, one of the most common bacterial pathogens in these patients. This work will lead to the identification of therapeutic targets for intervention to delay the rate of pulmonary decline in these patients.