Role of Macrophage Arginase in Anti-Bacterial Immunity

描述（申请人提供）：巨噬细胞功能的严格控制是炎症和免疫反应的核心。精氨酸酶I（Arginase I，Arg I）是新近发现的巨噬细胞活化标志物。在哮喘和其他涉及慢性炎症的疾病中，通常沉默的Arg I表达对感染因子的反应的深刻诱导表明，通过了解Arg I的生物学以及会聚以调节其表达的途径，可以揭示对免疫中巨噬细胞功能的新见解。然而，在理解Arg I在免疫应答背景下的功能方面的一个主要差距是将相关表达数据和体外发现翻译为体内系统，因为Arg I在肝功能中也起着不可替代的作用。为了解决这个问题，开发了小鼠模型，其中Arg I在巨噬细胞中特异性缺失或过表达。初步的数据建立了这些模型的保真度，并设置了一个阶段，详细检查的精氨酸我的功能，对细菌的免疫反应。将研究感染模型，因为Arg I功能最直接地涉及调节对细菌的免疫的两个途径：一氧化氮（NO）生物合成和促进纤维化。提出了四个目标，研究精氨酸生物学在巨噬细胞。在目的1中，将使用缺乏Arg I的系统来研究Arg I在调节NO的生物合成中的作用。在目的2中，将剖析Arg I在脓毒性休克模型中调节炎症、组织修复和NO生物合成中的作用。在目的3中，将研究Arg I在调节结核病的免疫和病理结果中的功能，结核病是一种依赖于精确控制NO水平以获得有效免疫的慢性疾病。在目标4中，我们将扩展我们目前的研究，精氨酸调节巨噬细胞，以确定病原体本身如何诱导表达。这些研究结果将揭示Arg I功能的新元素，并为将Arg I作为炎症性疾病的靶点提供理论依据。

DESCRIPTION (PROVIDED BY APPLICANT): The tight control of macrophage function is central to inflammatory and immune responses. Arginase I (Arg I) is a newly recognized marker of activated macrophages. The profound induction of normally silent Arg I expression in response to infectious agents, in asthma and in other diseases involving chronic inflammation suggests that new insights into macrophage function in immunity can be uncovered by understanding the biology of Arg I, and the pathways that converge to regulate its expression. However, a major gap in understanding Arg I function in the context of immune responses is the translation of correlative expression data and in vitro findings to in vivo systems because Arg I also plays an irreplaceable role in liver function. To address this problem, mouse models were developed where Arg I is specifically deleted or over-expressed in macrophages. The preliminary data establish the fidelity of these models and set the stage for a detailed examination of Arg I function in immune responses to bacteria. Infection models will be studied because Arg I function is most directly implicated in two pathways that regulate immunity to bacteria: nitric oxide (NO) biosynthesis and the promotion of fibrosis. Four aims are proposed to study Arg I biology in macrophages. In Aim 1, the role of Arg I in regulating the biogenesis of NO will be studied using systems deficient in Arg I. In Aim 2, the role of Arg I in regulating inflammation, tissue repair and NO biosynthesis in septic shock models will be dissected. In Aim 3, the function of Arg I in regulating the immunological and pathological outcomes in tuberculosis, a chronic disease that is dependent on exquisite control of NO levels for effective immunity, will be investigated. In Aim 4, we will extend our current studies of Arg I regulation in macrophages to determine how pathogens themselves induce expression. The outcomes of the proposed studies will reveal new elements of Arg I function and provide rationale for approaching Arg I as a target in inflammatory diseases.