The Staphylococcus aureus response to nutrient zinc restriction during infection

金黄色葡萄球菌感染期间对营养锌限制的反应

• 批准号: 10335212
• 负责人: Eric P Skaar
• 金额: $ 42.46万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-19 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10335212
• 关键词: Abscess; Antibiotic Resistance; Antibiotics; Area; Bacteria; Bacterial Infections; Binding; Cells; Client; Coupled; DNA Repair; Development; Ensure; Environment; Enzymes; Exposure to; Family; Gene Expression; Genome; Genus staphylococcus; Heterogeneity; Host Defense; Image; Imaging technology; Immune; Immune system; Immunologic Factors; Individual; Infection; Inflammatory; Invaded; Iron; Knowledge; Lead; Leukocyte L1 Antigen Complex; Maintenance; Manganese; Mediating; Metabolic; Metalloproteins; Metals; Modeling; Molecular; Morbidity - disease rate; Nutrient; Nutritional Immunity; Oxygen; Pathogenesis; Phagocytes; Physiology; Positioning Attribute; Process; Property; Proteins; Public Health; Research; Resistance; Role; Site; Staphylococcus aureus; Staphylococcus aureus infection; Starvation; Stress; System; Testing; Therapeutic; United States; Up-Regulation; Vertebrates; Work; Zinc; antimicrobial; base; cofactor; combat; defined contribution; deprivation; experience; experimental study; human pathogen; immunoregulation; infectious disease treatment; innovation; insight; member; metal chelator; microbial; mortality; novel therapeutics; pathogen; pathogenic bacteria; pathogenic microbe; recruit; resistant strain; response; therapeutic development

PROJECT SUMMARY Staphylococcus aureus is a significant cause of morbidity and mortality that is increasingly acquiring resistance to all available antibiotics. One promising area for antimicrobial development involves targeting bacterial acquisition and utilization of nutrient metal. This strategy exploits the fact that all bacterial pathogens require nutrient metal to colonize their hosts. In response to this requirement, vertebrates have evolved powerful defense strategies that sequester nutrient metals from invading pathogens in a process known as nutritional immunity. One of the most effective metal chelating factors of the immune system is calprotectin, an abundant protein that sequesters nutrient manganese, iron, and zinc and defends against microbial infection. In addition to its metal chelating properties, calprotectin is a potent pro-inflammatory molecule. The individual importance of each of these activities to protection against infection has not been parsed, and the contribution of calprotectin metal binding to its immunomodulatory properties is not known. Prevailing models suggest that nutritional immunity ensures that pathogens are uniformly metal starved during vertebrate colonization. We have challenged this concept through the application of innovative imaging technologies, revealing S. aureus is differentially metal starved within abscesses. This discovery necessitates a reevaluation of the environment encountered by S. aureus during infection, particularly as it pertains to nutrient metal levels. We have also discovered that the S. aureus response to metal restriction includes the up-regulation of members of the newly described COG0523 family of zinc metallochaperones. Our preliminary results reveal that these enzymes enable S. aureus to combat calprotectin-mediated zinc depletion by delivering zinc to critical metalloproteins involved in genome maintenance. Based on these fundamental discoveries, we hypothesize that following colonization of the vertebrate host, S. aureus encounters immune-mediated metal restriction through the delivery of calprotectin to the site of infection. In response, S. aureus up-regulates the expression of systems to combat this nutrient limitation. We envision that this microbial response is heterogeneous, and occurs in a manner dependent on the level of metal restriction experienced at distinct sites of infection. Finally, we predict that an important aspect of this response to nutrient limitation is the up-regulation of dedicated metallochaperones that deliver metal to proteins involved in DNA repair and are required for survival upon exposure to the reactive oxygen burst of the phagocyte. Experiments in this proposal will test this model by (i) defining the heterogeneous S. aureus response to metal starvation, (ii) elucidating the mechanism by which calprotectin protects against infection, and (iii) determining the subcellular fate of metal acquired by S. aureus during metal deprivation. This work will provide a mechanistic framework for understanding the importance of nutritional immunity during bacterial infection and reveal the corresponding S. aureus response to this host defense.

项目概要 金黄色葡萄球菌是发病率和死亡率的一个重要原因，并且越来越多地出现 对所有可用抗生素产生耐药性。抗菌药物开发的一个有前景的领域涉及靶向 细菌获取和利用营养金属。该策略利用了以下事实：所有细菌 病原体需要营养金属来定殖其宿主。为了满足这一要求，脊椎动物 进化出强大的防御策略，在一个过程中隔离营养金属免遭入侵病原体的侵害 称为营养免疫。免疫系统最有效的金属螯合因子之一是 钙卫蛋白，一种丰富的蛋白质，可隔离营养物质锰、铁和锌，并防御 微生物感染。除了其金属螯合特性外，钙卫蛋白还是一种有效的促炎剂 分子。这些活动对于预防感染的各自重要性尚未得到证实。 已解析，钙卫蛋白金属结合对其免疫调节特性的贡献尚不清楚。 流行的模型表明，营养免疫确保病原体一致缺乏金属 在脊椎动物定植期间。我们通过应用创新技术挑战了这一概念 成像技术显示，脓肿内的金黄色葡萄球菌存在不同程度的金属缺乏。这一发现 需要重新评估金黄色葡萄球菌在感染期间遇到的环境，特别是因为它 与营养金属水平有关。我们还发现金黄色葡萄球菌对金属限制的反应 包括新描述的 COG0523 锌金属伴侣家族成员的上调。 我们的初步结果表明，这些酶使金黄色葡萄球菌能够对抗钙卫蛋白介导的锌 通过将锌传递给参与基因组维护的关键金属蛋白来消耗锌。 基于这些基本发现，我们假设脊椎动物的殖民化之后 宿主，金黄色葡萄球菌通过将钙卫蛋白递送至该位点而遭遇免疫介导的金属限制 的感染。作为回应，金黄色葡萄球菌上调系统的表达来对抗这种营养限制。 我们设想这种微生物反应是异质的，并且以取决于水平的方式发生 在不同感染部位经历的金属限制。最后，我们预测一个重要方面 这种对营养限制的反应是专用金属伴侣的上调，这些金属伴侣将金属输送到 参与 DNA 修复的蛋白质，是暴露于活性氧爆发后生存所必需的 吞噬细胞。本提案中的实验将通过 (i) 定义异质金黄色葡萄球菌来测试该模型 对金属饥饿的反应，(ii) 阐明钙卫蛋白预防感染的机制， (iii) 确定金黄色葡萄球菌在金属缺乏期间获得的金属的亚细胞命运。这部作品 将为理解营养免疫的重要性提供一个机制框架 细菌感染并揭示金黄色葡萄球菌对此宿主防御的相应反应。