A Novel Metabolic Pathway Regulates Urinary Tract Infections in the Bladder

一种调节膀胱尿路感染的新代谢途径

基本信息

批准号：
10297547
负责人：
JONATHAN M. BARASCH
金额：
$ 26.07万
依托单位：
COLUMBIA UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-09-24 至 2026-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10297547
关键词：
Affect Affinity Americas Animals Autoradiography Back Bacteria Biliverdine Biological Assay Biology Biomedical Engineering Bladder Bladder mucosa Blood Circulation CRISPR/Cas technology Carbon Monoxide Carrier Proteins Cell division Cells Chelating Agents Chemicals Chemistry Citrates Clinic Communication Complex Crystallography Cytolysis DNA biosynthesis DNA metabolism Data Drug Metabolic Detoxication Duct (organ) structure Endocytic Vesicle Enterobactin Enzymes Epithelial Epithelial Cells Event Evolution Gene Deletion Generations Genes Genetic Growth Hematuria Heme Heme Iron Homeostasis Human Imaging Device Immune Infection Invaded Iron Iron Chelating Agents Kidney Klebsiella pneumoniae Knockout Mice LCN2 gene Mammals Measures Mediating Medicine Metabolic Metabolic Pathway Metabolism Metals Methods Microbe Mucous Membrane Mus Mutation Nature Nutrient Nutritional Nutritional Immunity Organ Organism Pathway interactions Patients Pharmacology Phase Physiological Play Process Production Prostate Protein Engineering Proteins Proteus mirabilis Publications RNA Reporter Role Science Scientist Series Siderophores Source Specialist System Testing Theft Time Toxic effect Transferrin Ureter Urethra Urinary tract Urinary tract infection Urine Urogenital Abnormalities Urogenital Diseases Urology Urothelial Cell Urothelium Visit Water Woman Work apical membrane chelation circadian pacemaker experimental study host-microbe interactions in vivo inorganic phosphate novel novel therapeutic intervention pressure prevent response response to injury small molecule tool trafficking urinary urogenital tract

项目摘要

PROJECT 3: PROJECT SUMMARY/ABSTRACT Urinary tract infections are the most common urogenital abnormality worldwide affecting multiple organs of the urinary tract including the urethra, bladder, prostate, ureter, and kidney. To establish a urinary tract infection, bacteria must obtain nutrients in order to undergo continuous replication. These nutrients derive from the urine and the epithelia of the urinary tract. Iron is a “precious metal” for bacteria because metabolic processes including energy production and cell division require ~100,000 atoms of iron per bacterium. Yet it is the most difficult nutrient to obtain because the common form, called ferric iron, is insoluble in water (Ksp=10-12M). Gram-negative organisms have devised methods to obtain iron even with these vanishing low concentrations. They do this by the production of a series of small molecules known as siderophores, each with astronomical affinity for iron. One type of siderophore, called Enterochelin is the most prevalent. Yet, the epithelial cells of the urogenital tract recognize this threat and rapidly produce a protein called NGAL (Lcn2) in great abundance. NGAL captures Ent:Fe and prevents its iron from reaching bacteria. We discovered that the urothelium and the tracts up into the kidney expresses NGAL. While most of our studies have focused on NGAL:Ent:Fe, there must be alternative nutrient pathways and alternative mammalian defenses. We propose that bacterial heme transporters also steal our iron and that epithelia in turn capture and metabolize heme. By adapting a novel method to analyze “snapshots” of nascent RNA, we found that bladder urothelia and collecting ducts express heme capture, heme metabolism, and iron sequestration and transport proteins, which compete with bacteria for heme. Most intriguing is our finding that upon infection, the urothelial “heme machine” is activated and releases a byproduct of heme metabolism, called Carbon Monoxide, a bacteriostatic agent. Moreover, the heme machine is the core complex of the Circadian Clock, which is regulated by CO. Here we test the basic tenets of our hypothesis. We carefully document heme and iron transport and metabolism in the urothelium to test the notion of that the urothelium and bacteria compete for heme. We suggest that these mechanisms are re-purposed for “nutritional immune defense” from the daily defense against the lysis of RBC that traverse the bladder each day. To investigate these mechanisms, we have invented novel methods of RNA isolation, imaging tools to detect bacterial responses, a method to detect and capture CO in vivo, novel mouse ko’s, and bacteria isolated from our patients with UTI’s carrying mutations in siderophore and heme pathways. We are working with a leading microbiologist (Uhlemann), animal geneticist (Mendelsohn), UTI specialist (Mysorekar) and the leading scientist in heme biology (Hamza). Taken together, our studies demonstrate that rather than a passive barrier, the urothelium is a metabolically active cell layer, that uses iron biology to detoxify hematuria and defend itself from UTI.

项目 3：项目摘要/摘要尿路感染是世界范围内最常见的泌尿生殖系统异常，影响多个器官泌尿道，包括尿道、膀胱、前列腺、输尿管和肾脏。细菌必须获得营养才能持续复制，这些营养来自尿液。泌尿道上皮细胞对细菌来说是一种“贵金属”，因为代谢过程包括每个细菌的能量产生和细胞分裂需要约 100,000 个铁原子，但这却是最困难的。由于其常见形式称为三价铁，不溶于水（Ksp=10-12M），因此无法获得营养。生物体已经设计出即使在低浓度的情况下也能获取铁的方法。产生一系列被称为铁载体的小分子，每种小分子对铁都具有天文数字的亲和力。一种称为肠螯素的铁载体在泌尿生殖道的上皮细胞中最为普遍。认识到这种威胁并迅速捕获大量称为 NGAL (Lcn2) 的蛋白质。 Ent：Fe 并防止其铁到达细菌。我们发现尿路上皮和尿道向上进入细菌。虽然我们的大多数研究都集中在 NGAL:Ent:Fe，但必须有替代方案。我们认为细菌血红素转运蛋白也会窃取。通过采用一种新的分析方法，我们的铁和上皮细胞反过来捕获和代谢血红素。新生RNA的“快照”，我们发现膀胱尿路上皮和集合管表达血红素捕获，血红素新陈代谢、铁螯合和运输蛋白质，它们与细菌竞争血红素。我们的发现是，感染后，尿路上皮“血红素机器”被激活并释放血红素副产品新陈代谢，称为一氧化碳，一种抑菌剂，此外，血红素机器是核心复合物。昼夜节律时钟由二氧化碳调节。在这里，我们仔细检验我们假设的基本原则。记录尿路上皮中血红素和铁的转运和代谢，以测试尿路上皮和我们建议将这些机制重新用于“营养免疫”。 “防御”来自对每天穿过膀胱的红细胞溶解的日常防御来研究这些。机制，我们发明了 RNA 分离的新方法、检测细菌反应的成像工具、检测和捕获体内 CO、新型小鼠 ko 以及从尿路感染患者中分离出的细菌的方法我们正在与一位领先的微生物学家合作。 (Uhlemann)、动物遗传学家 (Mendelsohn)、UTI 专家 (Mysorekar) 和血红素领域的领先科学家生物学（Hamza）综合起来，我们的研究表明，尿路上皮不是被动屏障，而是一种屏障。代谢活跃的细胞层，利用铁生物学来解毒血尿并防御尿路感染。