Iron Acquisition by Mycobacterium tuberculosis Within Phagocytes

吞噬细胞内结核分枝杆菌对铁的获取

• 批准号: 7685175
• 负责人: BRADLEY E BRITIGAN
• 金额: --
• 依托单位: CINCINNATI VA MEDICAL CENTER RESEARCH
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7685175
• 关键词: Acute; Anemia due to Chronic Disorder; Antibiotics; Antitubercular Agents; Bacteria; Bone Marrow; Cell membrane; Cells; Cellular biology; Chronic; Citrates; Clinical; Confocal Microscopy; Culture Media; Cytoplasm; Data; Defensins; Dendritic Cells; Development; Disease; Drug resistance in tuberculosis; Enzyme-Linked Immunosorbent Assay; FDA approved; Family; Francisella tularensis; Functional disorder; Gallium; Gene Mutation; Genetic; Growth; Health; Heme; Hepatocyte; Hereditary hemochromatosis; Homeostasis; Host Defense; Human; Hypercalcemia of Malignancy; Immunoblot Analysis; In Vitro; Individual; Infection; Interferons; Interleukin-6; Iron; Kinetics; Lactoferrin; Lead; Life; Link; Liver; Locales; Lung; Measures; Mediating; Metabolic Pathway; Metabolism; Methods; Microbe; Microbial Biofilms; Minority; Mission; Modeling; Movement; Multi-Drug Resistance; Mus; Mycobacterium tuberculosis; Myelogenous; Nature; Organism; Pathogenesis; Patients; Peptides; Phagocytes; Phagosomes; Pharmaceutical Preparations; Physiological; Platelet Factor 4; Play; Predisposition; Prevalence; Prevention strategy; Process; Production; Protein Export Pathway; Proteins; Pseudomonas aeruginosa; Pulmonary Tuberculosis; Research Support; Resistance; Reverse Transcriptase Polymerase Chain Reaction; Role; Route; Serum; Severity of illness; Siderophores; Site; Small Interfering RNA; Source; Spleen; Testing; Therapeutic Agents; Transferrin; Transition Elements; Tuberculosis; Veterans; Virulent; Work; base; cell type; cytokine; extracellular; heme oxygenase-1; hepcidin; high risk; in vivo; insight; macrophage; metal transporting protein 1; microbial; microbicide; novel; novel strategies; pathogen; public health relevance; response; trafficking; treatment strategy; tuberculosis drugs; tuberculosis treatment; uptake

DESCRIPTION (provided by applicant): The pathophysiology of tuberculosis (TB) is linked to the ability of the causative organism, Mycobacterium tuberculosis (M.tb), to grow within human macrophages. Lung myeloid dendritic cells are a newly recognized reservoir of M.tb during lung infection. M.tb metabolism in macrophages and dendritic cells may differ. Iron (Fe) acquisition is critical for M.tb growth. In vivo, most extracellular Fe is chelated to transferrin (TF) and lactoferrin (LF), decreasing microbial access to Fe. We find that M.tb in human macrophages can acquire Fe from TF and LF, as well as the macrophage cytoplasm. Fe uptake from extracellular TF and LF may involve Fe moving into the cytoplasm. Some (e.g. hereditary hemochromatosis) conditions that lower intracellular Fe in macrophages, decrease M.tb Fe uptake. Whether other factors that regulate macrophage Fe metabolism (e.g. ferroportin, heme oxygenase 1 (HO-1), hepcidin) impact M.tb Fe acquisition is unknown. Similarly unknown is whether Fe acquisition by M.tb growing in dendritic cells is different from that occurring in macrophages. We hypothesize that: 1) M.tb acquires Fe from an intracellular Fe pool(s) in macrophages and dendritic cells; 2) acquisition of extracellular Fe by M.tb involves initial Fe movement into this pool; 3) the kinetics/route of M.tb Fe uptake varies with the extracellular Fe chelate and host cell type (macrophage vs. dendritic cell) involved; 4) genetic or physiological factors that modulate macrophage and/or dendritic cell cytoplasmic Fe alter Fe available for use by M.tb; and 4) administration of Ga, which disrupts M.tb Fe-dependent metabolism could prove to be a novel therapy for TB. In order to test these hypotheses we will pursue the following specific aims: 1. Delineate and compare the ability of M.tb residing within human macrophages and myeloid dendritic cells to: A) acquire Fe from physiologic extracellular chelates (e.g. TF and LF) and from cytoplasmic sites in the macrophage and dendritic cell; and B) to what extent Fe acquisition from extracellular chelates involves initial Fe movement into these same cytoplasmic sites. 2. Determine: A) if M.tb modulates macrophage Fe metabolism, which in turn alters Fe acquisition and growth by the bacteria; and B) the role of key components of macrophage Fe metabolism (e.g. ferroportin, HFE, HO-1, hepcidin) on M.tb Fe acquisition and growth. 3. Determine the efficacy of Ga as a therapeutic agent against M.tb using a murine model of M.tb infection. If positive results are seen, further ascertain the mechanism(s) of Ga's anti-tuberculous activity. The proposed studies use human macrophages and dendritic cells along with fully virulent M.tb strains to accomplish these aims. Experimental methods employed include: measuring uptake of 59Fe, siRNA, confocal microscopy, immunoblot analysis, RT-PCR, and ELISA and use of a murine model of pulmonary TB. Insight into M.tb Fe metabolism could lead to novel treatments that would benefit veterans. PUBLIC HEALTH RELEVANCE: Project Narrative - Relevance to VA Mission: Veterans are at high risk for pulmonary TB. There is a growing problem in treating tuberculosis in that the causative organism, Myocobacterium tuberculosis, is becoming increasingly resistant to available antibiotics. The ability to acquire iron (Fe) from the infected host is required for M. tuberculosis to be able to grow and therefore cause infection. Insight into M. tuberculosis Fe metabolism could lead to development of novel approaches to interfere with the organism's ability to acquire Fe treatments that could lead to the development of new kinds of antibiotics. This application will explore one potential mechanism of doing this using gallium. Thus, increased understanding of how M. tuberculosis acquires and uses Fe during infection could lead to the development of new antibiotics to be used in treating TB, something that would be of great benefit to veterans.

描述（由申请人提供）： 结核病（TB）的病理生理与因果生物，结核分枝杆菌（M.TB）在人类巨噬细胞内生长的能力有关。肺髓样树突状细胞是肺部感染过程中新近认识的M.TB的储层。巨噬细胞和树突状细胞中的M.TB代谢可能有所不同。 铁（FE）的采集对于M.TB生长至关重要。在体内，大多数细胞外Fe螯合为转铁蛋白（TF）和乳铁蛋白（LF），从而减少了微生物进入FE的机会。我们发现，人类巨噬细胞中的M.TB可以从TF和LF以及巨噬细胞细胞质中获取Fe。细胞外TF和LF的FE摄取可能涉及Fe进入细胞质。一些（例如遗传性血色素沉着症）降低巨噬细胞中细胞内Fe的情况，可降低M.TB Fe摄取。其他调节巨噬细胞FE代谢的因素（例如铁磷酸素，血红素氧酶1（HO-1），肝素）是否影响M.TB Fe的获取尚不清楚。同样未知的是，在树突状细胞中生长的M.TB的Fe获取与巨噬细胞中发生的Fe是否不同。 我们假设：1）M.TB从巨噬细胞和树突状细胞中的细胞内Fe池中获取Fe； 2）M.TB获得细胞外Fe的涉及初始FE运动进入该池； 3）M.TB Fe摄取的动力学/途径随涉及的细胞外Fe螯合物和宿主细胞类型（巨噬细胞与树突状细胞）而变化； 4）调节巨噬细胞和/或树突状细胞胞质Fe Alter fe Fe fe的遗传或生理因素可用于M.TB； 4）GA的给药，破坏M.TB Fe依赖性代谢可能被证明是TB的一种新型疗法。 为了检验这些假设，我们将追求以下具体目的：1。划定并比较居住在人类巨噬细胞和髓样树突状细胞内的M.TB的能力： b）在多大程度上，从细胞外螯合物中获取Fe涉及初始FE运动到这些相同的细胞质部位。 2。确定：a）如果M.TB调节巨噬细胞FE代谢，从而改变了细菌的Fe获取和生长； b）巨噬细胞Fe代谢的关键组成部分（例如铁杆菌，HFE，HO-1，肝素）在M.TB获取和生长中的作用。 3。使用M.TB感染的鼠模型确定GA作为对M.TB的治疗剂的疗效。如果看到积极的结果，请进一步确定GA的抗抗可结核活性的机制。 拟议的研究使用人类巨噬细胞和树突状细胞以及完全有毒的M.TB菌株来实现这些目标。采用的实验方法包括：测量59FE，siRNA，共聚焦显微镜，免疫印迹分析，RT-PCR和ELISA的吸收，以及使用肺结核的鼠模型。 对M.TB FE代谢的洞察力可能导致新的治疗方法，从而使退伍军人受益。 公共卫生相关性： 项目叙述 - 与VA任务的相关性：退伍军人对肺结核的风险很高。治疗结核病的问题越来越大，因为致病生物，结核菌的肌肉杆菌正在变得越来越抗性可用的抗生素。从感染宿主那里获取铁（Fe）的能力是结核分枝杆菌能够生长并因此引起感染所必需的。对结核分枝杆菌FE代谢的见解可能会导致开发新的方法，以干扰该生物的获得Fe治疗的能力，从而导致新型抗生素的发展。该应用程序将探索使用镀与进行此操作的一种潜在机制。因此，对结核分枝杆菌在感染过程中如何获得和使用FE的了解增加可能导致用于治疗结核病的新抗生素的发展，这对退伍军人带来了很大的好处。