The impact of hypoxia on Staphylococcus aureus metabolism and virulence during osteomyelitis

骨髓炎期间缺氧对金黄色葡萄球菌代谢和毒力的影响

• 批准号: 9901431
• 负责人: JAMES E CASSAT
• 金额: $ 37.67万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-05-10 至 2022-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9901431
• 关键词: Admission activity; Amino Acids; Anti-Bacterial Agents; Antibiotics; Antimicrobial Resistance; Bacteria; Bone Regeneration; Bone remodeling; Carbon; Cell Death; Cells; Clinical; Cues; Data; Disease; Environment; Functional disorder; Genes; Genus staphylococcus; Glucose; Glycolysis; Growth; Health; Homeostasis; Host Defense; Hypoxia; Hypoxia Inducible Factor; Hypoxia-Inducible Factor Pathway; Immunity; In Vitro; Infection; Invaded; Lactic acid; Life; Maintenance; Measurement; Metabolic; Metabolic Pathway; Metabolism; Modeling; Mus; Musculoskeletal; Nutrient; Open Fractures; Osteitis; Osteoblasts; Osteoclasts; Osteogenesis; Osteomyelitis; Outcome; Oxygen; Pathogenesis; Pathologic; Pathway interactions; Pediatric Hospitals; Penetration; Physiological; Physiology; Production; Proliferating; Property; Pyruvate; Refractory; Resolution; Role; Signal Pathway; Signal Transduction; Skeleton; Source; Staphylococcus aureus; Staphylococcus aureus infection; System; Testing; Therapeutic; Tissues; Toxin; United States; Virulence; Virulence Factors; antimicrobial; bacterial fitness; bacterial metabolism; base; body system; bone; bone turnover; cytotoxicity; flexibility; glucose uptake; human pathogen; microbial; mouse model; mutant; pathogen; programs; quantitative imaging; quorum sensing; response; skeletal; skeletal tissue; success; transposon sequencing

PROJECT SUMMARY / ABSTRACT Staphylococcus aureus is an important human pathogen, capable of causing life-threatening infections in a variety of host tissues. Osteomyelitis, an invasive and debilitating infection of bone, is one of the most common manifestations of staphylococcal disease. Indeed, osteomyelitis accounts for approximately 2-3 of every 1,000 admissions to pediatric hospitals in the United States, and complicates up to 25% of open fractures. Bone infections are notoriously refractory to treatment due to widespread antimicrobial resistance and pathogen-induced bone remodeling, which limits penetration of antibiotics into the infectious focus. S. aureus is by far the most common cause of musculoskeletal infection, yet the mechanisms by which staphylococci survive within and ultimately destroy bone are poorly understood. The overarching objective of this proposal is to understand how S. aureus regulates its virulence and metabolic programs to survive within bone during osteomyelitis. Bone, like most mammalian tissues, is inherently hypoxic. Moreover, maintenance of skeletal health requires constant bone turnover by resident bone-forming osteoblasts and bone-resorbing osteoclasts. These skeletal cells, in turn, require a specialized metabolism characterized by high rates of glucose uptake, which is expected to limit the carbon sources available to invading pathogens. In order to better understand how S. aureus thrives within this hypoxic and metabolically unique environment, we created a powerful murine model of osteomyelitis capable of precise quantification of both bacterial burdens and bone turnover. By applying transposon sequencing (TnSeq) to this osteomyelitis model, we identified >200 staphylococcal genes important for survival in bone. Importantly, bacterial responses to hypoxia were found to be critical determinants of survival during osteomyelitis, as hypoxic growth not only dictates the energy production strategies used by staphylococci, but also augments the production of quorum-dependent virulence factors that participate in bone destruction. Based on these preliminary data, we hypothesize that S. aureus survival in bone is facilitated by (a) quorum-regulated virulence factor expression in response to hypoxia, and (b) specific nutrient utilization programs that enable growth in the unique metabolic environment of bone. The proposed Aims will test this hypothesis to determine (i) the mechanism by which hypoxic growth triggers increased staphylococcal virulence, (ii) the metabolic pathways that support bacterial growth in bone, and (iii) the role of host hypoxic signaling pathways in antibacterial immunity and bone remodeling during osteomyelitis. Completion of these studies will elucidate microbial survival strategies during invasive infection, determine the impact of hypoxia on bacterial pathogenesis, and help to meet a critical need for new osteomyelitis therapeutics by defining putative antimicrobial and anti-virulence targets.

项目摘要 /摘要 金黄色葡萄球菌是一种重要的人类病原体，能够引起威胁生命的感染 在各种宿主组织中。骨髓炎是骨骼的侵入性和使人衰弱的感染，是最大的一种 葡萄球菌疾病的共同表现。实际上，骨髓炎约为2-3 在美国，每1,000次入院医院，并使多达25％的开放式医院复杂 断裂。由于广泛的抗菌素耐药性，臭名昭著的骨骼感染是对治疗的难治性 病原体引起的骨重塑，这限制了抗生素渗透到感染性焦点中。 s 金黄色葡萄球菌是迄今为止肌肉骨骼感染的最常见原因，但是 葡萄球菌在内部生存，最终销毁骨骼的理解很少。的总体目标 该提议是了解金黄色葡萄球菌如何调节其毒力和代谢计划以生存 骨髓炎期间的骨头。 像大多数哺乳动物组织一样，骨骼本质上是低氧。此外，维持骨骼健康 需要固定的骨成骨细胞和骨质骨细胞的固定骨转换。这些 反过来，骨骼细胞需要一种专门的代谢，其特征在于葡萄糖摄取率高，这是 预计将限制可用于入侵病原体的碳源。为了更好地了解S。 金黄色葡萄球菌在这种缺氧和代谢独特的环境中蓬勃发展，我们创建了一个强大的鼠模型 能够精确定量细菌负担和骨转换的骨髓炎。通过申请 转座子测序（TNSEQ）到该骨髓炎模型，我们确定了> 200葡萄球菌基因 对于骨骼中的生存很重要。重要的是，发现细菌对缺氧是至关重要的 骨髓炎期间生存的决定因素，因为低氧生长不仅决定了能量产生 葡萄球菌使用的策略，但也增加了依赖群体依赖的毒力因子的产生 参与骨骼破坏。基于这些初步数据，我们假设金黄色葡萄球菌在 （a）对缺氧反应的（a）法定调节的毒力因子表达促进骨骼，（b）特定 营养利用计划可以在骨骼独特的代谢环境中增长。提议 目标将检验该假设，以确定（i）低氧增长触发者增加的机制 葡萄球菌毒力，（ii）支持骨骼细菌生长的代谢途径，以及（iii） 宿主缺氧信号通路抗菌免疫和骨髓炎期间骨骼重塑。 这些研究的完成将阐明在侵入性感染期间的微生物生存策略，确定 缺氧对细菌发病机理的影响，并有助于满足新骨髓炎的关键需求 通过定义假定的抗菌和抗病毒靶标的治疗剂。