A Novel Metabolic Pathway Regulates Urinary Tract Infections in the Bladder

项目3：项目摘要/摘要 尿路感染是泌尿外科最常见的医学问题，也是最普遍的医学问题之一。 疾病。患者表现为一系列强烈的下尿路症状，到一过性较少。 定义为不适和非诊断性尿路发现。我们相信出现症状的结果 来自不同地点的细菌和这些地点不同程度的毒力。我们的初步数据 表明细菌的嗜性和毒力与细菌获得营养的能力直接相关，以及 最令人垂涎的物质是铁。铁对细菌来说是一种“贵金属”，因为所有的代谢过程， 包括能量生产和细胞分裂在内，每个细菌需要10万个原子。泌尿系统是一种 特别耐人寻味的铁获取地点，因为虽然尿液中只含有纳米摩尔的铁含量， 尿液每天还含有106个红细胞，每个红细胞含有109个血红素铁原子。在这种铁制的背景下 饥饿，但潜在的血红素-铁丰富，细菌可以迅速部署工具，从 哺乳动物的蛋白质，以及直接穿过它们的膜的血红素环。我们建议这个设置是 由血红素铁主导，而血红素运输系统最初优先窃取我们的铁。这 假说不仅源于对细菌基因表达的分析，也源于我们对上皮细胞的研究 对侵犯膀胱的反应。通过创造新的工具来分离新生RNA的快照，我们 发现尿路上皮和泌尿系统其他地方的特化细胞激活自己的系统 血红素捕获、血红素新陈代谢和铁的封存。这些被激活的哺乳动物通路是非常重要的 兴趣，因为他们的反应是直接的，招募新的血红素转运体在网站上 细菌侵袭，以及生产的产品，一氧化碳，一种抑菌剂。此外, 这些途径不仅净化血红素，而且是生物钟的核心复合体。我们是 认识到这些发现的影响将需要大量的研究，但它们包括我们的发现 膀胱的顶膜，即尿路上皮，可以通过一种新的机制运输血红素，而尿路上皮 认识到细菌刺激这一过程是作为一种被称为营养的先天免疫防御机制 豁免权。由于这些机制的作用，我们发现夜间和白天UTI产生的时间不同 生物学结果。在哥伦比亚大学乔治·M·奥布莱恩泌尿学项目3的更新提案中 研究中心，我们回到基本的铁生物学，我们仔细地记录了血红素和铁在 用新的成像工具和新的铁和一氧化碳捕获工具研究小鼠的膀胱、细胞和细菌反应 KO‘s和细菌携带铁途径的突变，这对小鼠和人类感染至关重要。我们与 领先的微生物学家(Uhlemann)、遗传学家(Mendelsohn、Gharavi)和铁生物学的首席科学家 (哈姆扎)。总之，我们的研究将证明尿路上皮是一种代谢活跃的细胞层，它使用 铁生物，以解毒每日镜检血尿和免疫防御入侵。

PROJECT 3: PROJECT ABSTRACT/SUMMARY Urinary tract infections are the most common medical problem in Urology, and one of the most pervasive medical illnesses. Patient presentation falls along a spectrum of intensive, lower urinary tract symptoms, to transient less defined discomfort and non-diagnostic urinary findings. We believe the spectrum of presenting symptoms results from different sites of colonization of bacteria and different levels of virulence at those sites. Our preliminary data indicates the bacterial tropism and virulence is directly related to the capacity of bacteria to obtain nutrients, and the most coveted substance is iron. Iron is a “precious metal” for bacteria because all metabolic processes, including energy production and cell division requires 100,000 atoms per bacteria. The urinary system is a particularly intriguing site of iron acquisition, because while the urine fluid contains only Nano-Molar iron content, the urine also contains 106 red blood cells/day, containing 109 heme iron atoms each. In this setting of iron starvation, yet potentially heme-iron abundance, bacteria can rapidly deploy tools to transfer iron from mammalian proteins, and from heme rings directly across their membrane. We propose that this setting is dominated by heme iron, and that heme transport systems take priority initially in stealing our iron. This hypothesis not only derives from analysis of bacterial gene expression, but also our study of the epithelial response to the invasion of the bladder. By creating novel tools to isolate snapshots of nascent RNA, we discovered that the urothelium and specialized cells elsewhere in the urinary system activate their own system of heme capture, heme metabolism, and iron sequestration. These activated mammalian pathways are of great interest because of the immediacy of their responses, the recruitment of novel heme transporters at the site of bacterial attack, and the production of the heme product, Carbon Monoxide, a bacteriostatic agent. In addition, these pathways not only decontaminate heme, but they are the core complex of the Circadian Clock. We are cognizant that the implications of these findings will require considerable research, but they include our finding that the apical membrane of the bladder, the urothelium, can transport heme with a novel mechanism and the realization that bacteria stimulate this process as a mechanism of innate immune defense known as nutritional immunity. As a result of these mechanisms, we found that night time and day time UTI generate different biological outcomes. In this renewal proposal for Project 3 of the Columbia University George M. O’Brien Urology Research Center we go back to basic iron biology and we carefully document heme and iron transport across the bladder, cell and bacterial responses using novel imaging tools and novel iron and CO capture tools, mouse ko’s and bacteria carrying mutations in iron pathways that are critical in mice and human infection. We work with leading microbiologists (Uhlemann), geneticists (Mendelsohn, Gharavi) and lead scientist in iron biology (Hamza). Together, our studies will demonstrate that the urothelium is a metabolically active cell layer that uses iron biology to detoxify the daily microscopic hematuria and for immune defense upon their invasion.