Harnessing iron acquisition to hinder enterobacterial pathogenesis

利用铁的获取来阻碍肠细菌的发病机制

• 批准号: 10651432
• 负责人: ELIZABETH M NOLAN
• 金额: $ 66.95万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-23 至 2028-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10651432
• 关键词: Adherent Invasive Escherichia coli; Affect; Affinity; Anabolism; Anaerobic Bacteria; Anti-Bacterial Agents; Antibiotics; Antibodies; Applications Grants; B-Lymphocytes; Bacteremia; Binding; Biology; Carrier Proteins; Cell physiology; Colitis; Complex; Crohn' s disease; Cytoplasm; Data; Dedications; Development; Diarrhea; Electron Transport; Enterobactin; Environment; Escherichia coli; Escherichia coli Infections; Foundations; Future; Gastrointestinal tract structure; Genes; Goals; Growth; Gut Mucosa; Immunization; In Vitro; Infection; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Iron; Laboratories; Mediating; Membrane; Meningitis; Metabolism; Metals; Microbe; Morbidity - disease rate; Mucous Membrane; Mus; Nutrient; Organism; Outcome; Oxidation-Reduction; Pathogenesis; Pathogenicity; Patients; Peyer' s Patches; Process; Public Health; Reporting; Research; Respiration; Salmonella; Salmonella typhimurium; Sepsis; Severity of illness; Siderophores; Site; System; Testing; Therapeutic; Transition Elements; United States; Urinary tract; Urinary tract infection; Work; antimicrobial; beta-Lactams; design; enteric pathogen; expectation; gut colonization; gut inflammation; gut microbiome; in vivo; insight; microbiome composition; microbiota; mutant; non-typhoidal Salmonella; pathobiont; pathogen; pathogenic bacteria; patient population; periplasm; receptor; receptor expression; scaffold; secondary metabolite; siderophore receptors; uptake

PROJECT SUMMARY The primary objective of this application is to investigate siderophore-based immunization and antibiotic delivery strategies designed to inhibit the growth of Escherichia coli and non-typhoidal Salmonella (NTS). These Gram-negative facultative anaerobic bacteria are major causes of infections in diverse patient populations. E. coli includes commensal organisms, pathogens, and pathobionts (organisms that are usually harmless but are pathogenic in some settings) and cause infections that include urinary tract infections (UTI), bacteremia, meningitis, and sepsis. Moreover, a pathovar known as adherent-invasive E. coli (AIEC) is commonly isolated from patients with Crohn’s disease, a form of inflammatory bowel disease. NTS, including Salmonella enterica serovar Typhimurium (STm), are major causes of inflammatory diarrhea. The primary site of E. coli and NTS colonization is the gastrointestinal tract, where these organisms thrive during colitis and disseminate to other body sites. Recent studies, including work from our laboratories, demonstrate that iron (Fe) availability is a key factor for the progression of E. coli and NTS colonization in the gut, motivating the research proposed in this grant application. Our central hypothesis is that targeting siderophores and their uptake machineries can limit enteric pathogen growth in vitro and in vivo. Both E. coli and NTS deploy the catecholate siderophores enterobactin (Ent) and salmochelin (DGE, diglucosylated enterobactin) in the gut to scavenge Fe3+ from the host. We propose that blocking Ent&DGE-mediated Fe3+ acquisition by bacterial pathogens or targeting Ent&DGE transport systems to deliver antibiotics will provide a means to inhibit the growth of STm and AIEC in the inflamed gut. In support of this notion, we developed a siderophore-based immunization based on Ent that inhibits STm and AIEC growth in the murine gut, and we synthesized and evaluated siderophore-antibiotic conjugates (SACs) based on the Ent&DGE scaffold that target E. coli and STm. In Aim 1, we will use mutants in Fe acquisition genes in STm and AIEC to test whether CTB-Ent immunization results in specific inhibition of pathogen growth and association with the gut mucosa when the pathogen produces Ent&DGE; determine the effect of CTB-Ent immunization on the mucosal-associated versus luminal microbiota; and ascertain whether neutralizing anti- Ent&DGE Ig mediate protection by limiting pathogen association with the mucosa. In Aim 2, we will evaluate the antimicrobial activity of three Ent&DGE-based SACs. Studies in vitro will largely focus on how key environmental variables that characterize diverse host environments affect the antimicrobial activity of SACs, whereas studies in vivo will evaluate the consequences of SAC administration on the gut microbiome composition as well as on inhibiting mucosal expansion of STm and AIEC during colitis. This work may lead to future development of siderophore-binding antibodies and SACs as therapeutics to limit colonization of enteric pathogens and pathobionts in the inflamed gut.

项目概要 该应用程序的主要目的是研究基于铁载体的免疫和抗生素 旨在抑制大肠杆菌和非伤寒沙门氏菌（NTS）生长的递送策略。 革兰氏阴性兼性厌氧菌是不同患者群体感染的主要原因。 大肠杆菌包括共生生物、病原体和致病生物（通常无害但易感染的生物） 在某些情况下是致病性的）并引起感染，包括尿路感染（UTI）、菌血症、 此外，通常分离出一种称为粘附性侵袭性大肠杆菌（AIEC）的病原体。 来自克罗恩病患者，这是一种炎症性肠病，包括肠道沙门氏菌。 鼠伤寒血清型 (STm) 是引起炎症性腹泻的主要原因。大肠杆菌和 NTS 的主要致病菌。 定植在胃肠道，这些微生物在结肠炎期间在这里繁衍生息并传播到其他地方 最近的研究（包括我们实验室的工作）表明，铁 (Fe) 的可用性是关键。 大肠杆菌和 NTS 定植在肠道中进展的因素，激发了本研究中提出的研究 我们的中心假设是靶向铁载体及其摄取机制可以限制。 大肠杆菌和 NTS 均部署儿茶酚铁铁载体。 肠菌素 (Ent) 和沙莫螯素 (DGE，二葡萄糖基化肠菌素) 在肠道中清除宿主体内的 Fe3+。 我们建议阻断细菌病原体对 Ent&DGE 介导的 Fe3+ 获取或靶向 Ent&DGE 输送抗生素的运输系统将提供一种抑制发炎部位 STm 和 AIEC 生长的方法 为了支持这一观点，我们开发了一种基于 Ent 的铁载体免疫，可抑制 STm。 和 AIEC 在小鼠肠道中的生长，我们合成并评估了铁载体-抗生素缀合物 (SAC) 基于针对大肠杆菌和 STm 的 Ent&DGE 支架。在目标 1 中，我们将使用突变体来获取 Fe。 STm 和 AIEC 中的基因，用于测试 CTB-Ent 免疫是否会导致病原体生长的特异性抑制 当病原体产生Ent&DGE时与肠粘膜的关联确定了CTB-Ent的作用； 对粘膜相关微生物群和管腔微生物群进行免疫接种，并确定是否中和抗- Ent&DGE Ig 通过限制病原体与粘膜的关联来介导保护。在目标 2 中，我们将评估 三种基于 Ent&DGE 的 SAC 的抗菌活性体外研究将主要关注环境的关键程度。 不同宿主环境的变量会影响 SAC 的抗菌活性，而研究 体内将评估 SAC 给药对肠道微生物组组成以及对肠道菌群组成的影响。 抑制结肠炎期间 STm 和 AIEC 的粘膜扩张这项工作可能会导致未来的发展。 铁载体结合抗体和 SAC 作为限制肠道病原体定植的治疗剂 发炎肠道中的病原体。