MT VET COBRE PROJECT 2: HEME UPTAKE PATHWAYS IN GRAM-POSITIVE PATHOGENS

MT VET COBRE 项目 2：革兰氏阳性病原体中的血红素摄取途径

• 批准号: 7960526
• 负责人: BENFANG LEI
• 金额: $ 15.09万
• 依托单位: MONTANA STATE UNIVERSITY - BOZEMAN
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-25 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7960526
• 关键词: Antibiotics; Bacteria; Centers of Research Excellence; Computer Retrieval of Information on Scientific Projects Database; Emerging Communicable Diseases; Funding; Grant; Heme; Hemeproteins; Hemoglobin; Human; In Vitro; Infection; Institution; Iron; Kinetics; Mediating; Modeling; Molecular; Pathway interactions; Process; Proteins; Research; Research Personnel; Resources; Source; Staphylococcus aureus; Streptococcus pyogenes; System; United States National Institutes of Health; base; clinically relevant; combat; design; novel therapeutics; pathogen; therapeutic target; translational study; uptake

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The major human bacterial pathogens Streptococcus pyogenes and Staphylococcus aureus have evolved the systems to efficiently acquire heme from host hemoproteins as a preferred source of essential iron. Thus, these systems provide several potential therapeutic targets, and the mechanistic study on these systems will provide clinically relevant antibiotic strategies to inhibit the heme acquisition process mediated by these systems for treating S. pyogenes and S. aureus infections. Translational studies to develop the antibiotic strategies need to first understand and establish the molecular mechanism of the heme acquisition process and its structural basis. Thus, Dr. Lei's lab has designed an in vitro strategy to elucidate the pathway of heme acquisition in these pathogens. These studies physically demonstrated heme transfer from one protein to another and used kinetic analysis to determine whether the heme transfer is directional. Dr. Lei's previous results indicated the S. pyogenes pathway of heme transfer from hemoglobin to Shr, then to Shp, and finally to HtsA. Dr. Lei has now discovered that for the S. aureus system: (1) hemoglobin directly transfers heme to apo-IsdB; (2) holo-IsdB directly transfers heme to apo-IsdA and apo-IsdC, but not to apo-IsdE; (3) apo-IsdE directly acquires heme from holo-IsdC, but not from holo-IsdB and holo-IsdA; and (4) IsdB and IsdC enhance heme transfer from hemoglobin to apo-IsdC and from holo-IsdB to apo-IsdE, respectively. These results establish a S. aureus heme transfer pathway of hemoglobin IsdB IsdA IsdC IsdE. These results greatly enhance our understanding of the mechanisms of heme acquisition in S. pyogenes and S. aureus and may serve as a general model for heme acquisition in many other Gram-positive pathogens. Understanding of how these bacteria utilize heme to survive in humans may provide clues on how to block the heme transport for developing new therapeutics to combat these harmful pathogens.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目及 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 主要的人类细菌病原体化脓性链球菌和金黄色葡萄球菌已经进化出能够从宿主血红素蛋白中有效获取血红素的系统，作为必需铁的首选来源。因此，这些系统提供了几个潜在的治疗靶点，并且对这些系统的机制研究将提供临床相关的抗生素策略来抑制由这些系统介导的血红素获取过程，从而治疗化脓性链球菌和金黄色葡萄球菌感染。 开发抗生素策略的转化研究需要首先了解和建立血红素获取过程的分子机制及其结构基础。 因此，雷博士的实验室设计了一种体外策略来阐明这些病原体获取血红素的途径。 这些研究以物理方式证明了血红素从一种蛋白质转移到另一种蛋白质，并使用动力学分析来确定血红素转移是否是定向的。 雷博士之前的研究结果表明，化脓性链球菌将血红素从血红蛋白转移到Shr，然后转移到Shp，最后转移到HtsA。雷博士现已发现，对于金黄色葡萄球菌系统：（1）血红蛋白直接将血红素转移至apo-IsdB； (2)holo-IsdB直接将血红素转移至apo-IsdA和apo-IsdC，但不转移至apo-IsdE； (3) apo-IsdE直接从holo-IsdC获取血红素，而不是从holo-IsdB和holo-IsdA获取血红素； (4)IsdB和IsdC分别增强血红素从血红蛋白到apo-IsdC的转移以及从holo-IsdB到apo-IsdE的转移。 这些结果建立了血红蛋白 IsdB IsdA IsdC IsdE 的金黄色葡萄球菌血红素转移途径。 这些结果极大地增强了我们对化脓性链球菌和金黄色葡萄球菌中血红素获取机制的理解，并且可以作为许多其他革兰氏阳性病原体中血红素获取的通用模型。 了解这些细菌如何利用血红素在人体中生存，可能会为如何阻止血红素运输提供线索，从而开发新的疗法来对抗这些有害病原体。