M. Tuberculosis Influences Host Matrix Metalloproteinases and Granuloma Formation

结核分枝杆菌影响宿主基质金属蛋白酶和肉芽肿形成

• 批准号: 8061054
• 负责人: Nicole Christine Ammerman
• 金额: $ 4.84万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8061054
• 关键词: Acquired Immunodeficiency Syndrome; Address; Adenylate Cyclase; Affect; Animal Model; Antibodies; Bacteria; Belief; Biological; Cell Wall; Cells; Cessation of life; Collection; Colony-forming units; Complement; Cyclic AMP; Cytoplasm; Data; Development; Diffuse; Diffusion; Dinoprostone; Disease; Drug Delivery Systems; Environment; Enzymes; Evaluation; Event; Extracellular Matrix; Gene Expression; Generations; Genes; Genus Mycobacterium; Granuloma; Growth; Host Defense; Human; Immune response; Immunohistochemistry; In Vitro; Individual; Infection; Laboratories; Lung; Maintenance; Matrix Metalloproteinases; Measures; Membrane; Modeling; Molecular; Mycobacterium tuberculosis; Nature; Organism; Oryctolagus cuniculus; Pathogenesis; Pathology; Pathway interactions; Phenotype; Population; Process; Production; Proteins; Research; Reverse Transcriptase Polymerase Chain Reaction; Role; Signal Transduction; Structure; Structure of parenchyma of lung; Technology; Testing; Time; Transcript; Tuberculosis; Virulence; cyclooxygenase 2; design; in vivo; interest; macrophage; mutant; mycobacterial; new therapeutic target; novel; pathogen; prevent; protein expression; pulmonary granuloma; research and development; research study; response; synthetic polymer Bioplex; tuberculosis granuloma

DESCRIPTION (provided by applicant): Mycobacterium tuberculosis is an ancient pathogen that continues to flourish within the modern human population, causing 1.9 million deaths annually across the globe. Additionally, M. tuberculosis is a major AIDS- related opportunistic pathogen. The hallmark feature of tuberculosis, the granuloma, is a defined cellular aggregate within the lung tissue, surrounding and containing the initial focus of infection. Granuloma formation has long been understood as the primary host defense against M. tuberculosis; however, this structure also serves as a reservoir for the long-term maintenance of viable mycobacteria within an infected individual, and recent studies indicate that the ability of M. tuberculosis to initiate granuloma development is an important virulence determinant for this organism. Therefore, molecular factors that contribute to formation of the granuloma represent potential targets that could disrupt the ability of M. tuberculosis to efficiently infect and persist within the human population. Recently, our laboratory has characterized an M. tuberculosis-encoded adenylate cyclase (Rv0386) responsible for the production of 3', 5'-cyclic adenosine monophosphate (cAMP) that is directly injected into the host cell, and preliminary data indicate that this mycobacterial-derived cAMP may affect signaling events involved in development of the granuloma. We hypothesize that the active efflux of cAMP from M. tuberculosis influences the host response to promote a local environment favorable for mycobacterial survival within the granuloma structure, and we have designed three specific research aims to address this hypothesis. First, we will examine how M. tuberculosis secretes cAMP across the bacterial membrane into the host cell. The hydrophilic nature of the cAMP molecule precludes its diffusion across biological membranes, and we will utilize an extensive mutant collection to identify M. tuberculosis genes important for cAMP efflux during growth in broth culture. Second, we will evaluate how the mycobacterial-derived cAMP affects host cell signaling events involved in the production and secretion of matrix metalloproteinases (MMPs). These enzymes are responsible for breakdown of the lung extracellular matrix, a process that is critical for granuloma formation. We propose to use the M. tuberculosis adenylate cyclase mutant (JHU-0386), as well as a complemented strain, to analyze the role of cAMP on the gene and protein expression of human MMPs, as well as on the signaling events leading to this expression, following M. tuberculosis infection in cultured human monocytic cells. Third, we will utilize the JHU-0386 mutant to characterize the role of the mycobacterial-derived cAMP during in vivo granuloma formation and development within a novel rabbit model of tuberculosis. Overall, in the endeavor to further understand M. tuberculosis pathogenesis and identify new therapeutic targets against this organism, this project combines in vitro and in vivo experiments to study both bacterial and host cell factors involved in development of the lung granuloma following an M. tuberculosis infection. PUBLIC HEALTH RELEVANCE: It is currently estimated that one-third of the world's population is infected with the bacteria that cause tuberculosis. This infection is characterized by a lung structure called the granuloma, which allows these bacteria (Mycobacterium tuberculosis) to survive quietly for decades within infected individuals. This project is designed to study an aspect of granuloma development, and this research may identify new drug targets to treat tuberculosis in humans.

描述（由申请人提供）：结核分枝杆菌是一种古老的病原体，在现代人群中持续流行，每年在地球仪造成190万人死亡。此外，M.结核病是一种主要的艾滋病相关的机会致病菌。结核病的标志性特征是肉芽肿，它是肺组织内的一种明确的细胞聚集体，包围并包含最初的感染病灶。肉芽肿的形成一直被认为是宿主抵抗M.肺结核;然而，这种结构也作为一个水库长期维持活分枝杆菌在感染的个人，和最近的研究表明，能力的M。结核病引发肉芽肿发展是这种生物体的重要毒力决定因素。因此，有助于肉芽肿形成的分子因子代表了可能破坏M.结核病有效地感染并在人群中持续存在。最近，我们的实验室已经表征了M。结核病编码的腺苷酸环化酶（Rv 0386）负责产生直接注入宿主细胞的3 '，5'-环腺苷酸（cAMP），并且初步数据表明这种分枝杆菌衍生的cAMP可能影响肉芽肿发展中涉及的信号传导事件。我们推测M.结核病影响宿主反应，以促进肉芽肿结构内有利于分枝杆菌生存的局部环境，我们设计了三个具体的研究目标来解决这一假设。首先，我们来看看M。结核杆菌分泌cAMP穿过细菌膜进入宿主细胞。cAMP分子的亲水性阻止了其穿过生物膜的扩散，我们将利用大量的突变体来鉴定M。在肉汤培养物生长期间对cAMP流出重要的结核病基因。其次，我们将评估分枝杆菌衍生的cAMP如何影响参与基质金属蛋白酶（MMPs）的产生和分泌的宿主细胞信号传导事件。这些酶负责肺细胞外基质的分解，这是肉芽肿形成的关键过程。我们建议使用M。结核腺苷酸环化酶突变体（JHU-0386）以及互补菌株，以分析cAMP对人MMPs的基因和蛋白表达的作用，以及对导致这种表达的信号传导事件的作用。结核感染培养的人单核细胞。第三，我们将利用JHU-0386突变体来表征分枝杆菌衍生的cAMP在新型兔结核病模型中体内肉芽肿形成和发展过程中的作用。总的来说，奋进进一步了解M。结核病的发病机制，并确定新的治疗目标，对这种生物体，该项目结合在体外和体内实验，研究细菌和宿主细胞因子参与肺肉芽肿的发展后，M。肺结核感染。 公共卫生相关性：据估计，目前世界上三分之一的人口感染了导致结核病的细菌。这种感染的特征是肺部结构称为肉芽肿，这使得这些细菌（结核分枝杆菌）在感染者体内安静地存活数十年。该项目旨在研究肉芽肿发展的一个方面，这项研究可能会发现治疗人类结核病的新药物靶点。