The impact of host hypoxic signaling on antibacterial immunity and bone repair during Staphylococcus aureus osteomyelitis

金黄色葡萄球菌骨髓炎期间宿主缺氧信号对抗菌免疫和骨修复的影响

• 批准号: 9883705
• 负责人: Caleb Anthony Ford
• 金额: $ 5.05万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-03-01 至 2022-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9883705
• 关键词: Adjuvant; Affect; Anti-Bacterial Agents; Anti-Infective Agents; Antibiotic Therapy; Antibiotics; Architecture; Bacteria; Bacterial Infections; Biocompatible Materials; Biomedical Engineering; Blood Vessels; Bone Diseases; Bone Regeneration; Bone Resorption; Bone remodeling; Cell Lineage; Cells; Cellular biology; Clinical; Coculture Techniques; Cytokine Receptors; Data; Exposure to; Fracture Healing; Future; Genes; Genetic Transcription; Goals; Gram-Positive Bacteria; Homeostasis; Human; Hypoxia; Hypoxia Inducible Factor; Hypoxia-Inducible Factor Pathway; Immune; Immune response; Immunity; In Vitro; Infection; Infiltration; Inflammatory; Innate Immune Response; Ligands; Measurement; Measures; Mediating; Mentorship; Metabolic; Metabolism; Modeling; Mus; NF-kappa B; Necrosis; Osteoblasts; Osteoclasts; Osteolytic; Osteomyelitis; Oxygen; Pathogenesis; Pathologic; Pattern recognition receptor; Physicians; Production; Regulation; Research; Research Personnel; Research Proposals; Risk; Role; Science; Scientist; Shapes; Signal Transduction; Site; Staphylococcal Infections; Staphylococcus aureus; Structure; Testing; Therapeutic Agents; Tissues; Toxin; Training; Tumor necrosis factor receptor 11b; Vascular Endothelial Growth Factors; Vascular blood supply; angiogenesis; bone; bone healing; bone loss; career; cell behavior; chronic infection; combat; comorbidity; conditional knockout; cytokine; experimental study; fracture risk; human disease; immunoregulation; in vivo; mineralization; mouse genetics; mouse model; osteoblast differentiation; osteoclastogenesis; pathogen; pathogen exposure; pathogenic bacteria; receptor; repaired; response; skeletal; targeted treatment; therapeutic evaluation; tissue oxygenation

PROJECT SUMMARY/ABSTRACT Osteomyelitis is an inflammatory state of bone most commonly triggered by the Gram-positive bacterium Staphylococcus aureus. Staphylococcal infection of bone is both common and highly morbid. During osteomyelitis, the structural matrix and vascular architecture of bone is destroyed, resulting in regions of necrotic, avascular tissue that increase risk of chronic infection. Extreme hypoxia occurs during osteomyelitis due to an altered vascular supply, inflammatory infiltration, and the metabolism of invasive S. aureus. The host responds to hypoxia by initiating hypoxia-inducible factor (HIF) signaling. HIF signaling, in turn, modulates bone remodeling. Beyond bone homeostasis and repair, HIF signaling is implicated in the regulation of antibacterial immunity. However, the role of hypoxia and HIF signaling during osteomyelitis is unknown and may serve as an important clinical target for optimizing immune responses to combat invasive infection. We have developed a powerful murine model of osteomyelitis that recapitulates the pathogenesis of human disease. Using this model, we demonstrated that extreme hypoxia is present at the infectious focus in a manner independent of non-infectious fracture healing. Our preliminary data demonstrate that VEGF, a well- characterized target of HIF signaling, is increased during osteomyelitis relative to mock-infected bone, consistent with the notion that HIF signaling is activated during invasive infection of bone. Under normoxia, we also observed that osteoblasts (bone-building cells) sense and respond to S. aureus stimulation in vitro by increasing the transcription of genes that regulate HIF signaling, control host-mediated bone remodeling, and mediate innate immune responses. The overarching hypothesis of this proposal is that tissue oxygenation and host hypoxic signaling responses influence antibacterial immunity and bone repair during S. aureus osteomyelitis. I will test this hypothesis with two integrated Specific Aims. In Specific Aim 1, I will define the role of oxygenation in mediating osteoblast innate immune responses and bone homeostasis in response to S. aureus stimulation in vitro. In Specific Aim 2, I will determine the impact of HIF signaling on antibacterial immunity and bone remodeling during S. aureus osteomyelitis. Within the experiments of Aim 2, I will use in vivo analyses that will harness both mouse genetics and biomaterial science to alter HIF signaling during osteomyelitis and investigate the impact of HIF on immune responses and bone repair. Together these studies will 1) define the role of oxygenation in dictating the innate immune and bone remodeling responses of osteoblasts, 2) define the impact of osteoblast HIF signaling on antibacterial immunity and bone repair during S. aureus osteomyelitis, and 3) test the potential of HIF-targeted therapies as an anti-infective adjuvant for invasive infection of bone. Collectively, this proposal will elucidate how oxygenation impacts skeletal cell biology and the innate immune responses to bacterial pathogens while providing ideal training and mentorship to develop my future career as an independent investigator and physician-scientist.

项目总结/摘要 骨髓炎是一种炎症状态的骨最常见的触发革兰氏阳性菌 金黄色葡萄球菌。葡萄球菌性骨感染是一种常见且高度病态的疾病。期间 在骨髓炎中，骨的结构基质和血管结构被破坏，导致 增加慢性感染风险坏死无血管组织。骨髓炎时出现极度缺氧 这是由于血管供应改变、炎症浸润和侵袭性链球菌代谢所致。金黄色。主机 通过启动缺氧诱导因子（HIF）信号传导来响应缺氧。HIF信号反过来又调节 骨重建除了骨内稳态和修复，HIF信号转导还参与调节骨内稳态和修复。 抗菌免疫然而，缺氧和HIF信号在骨髓炎中的作用尚不清楚 并且可以作为优化免疫应答以对抗侵袭性疾病的重要临床靶点。 感染我们已经建立了一个强大的小鼠骨髓炎模型，该模型概括了 人类疾病使用这个模型，我们证明了极端缺氧是目前在感染病灶， 独立于非感染性骨折愈合的方式。我们的初步数据表明，VEGF，一个很好的- HIF信号传导的特征性靶点，在骨髓炎期间相对于模拟感染的骨增加， 这与HIF信号传导在骨的侵入性感染期间被激活的概念一致。在常氧条件下，我们 还观察到成骨细胞（骨生成细胞）对S.金黄色葡萄球菌体外刺激 增加调节HIF信号传导、控制宿主介导的骨重建的基因的转录，以及 介导先天免疫反应。这项提议的首要假设是，组织氧合和 宿主缺氧信号反应影响S.金黄色 骨髓炎我将用两个综合的具体目标来检验这个假设。在具体目标1中，我将定义 氧合在介导成骨细胞天然免疫应答和骨稳态中的作用。 金黄色葡萄球菌体外刺激。在具体目标2中，我将确定HIF信号传导对抗菌作用的影响。 免疫和骨重建。金黄色骨髓炎在目标2的实验中，我将使用 体内分析将利用小鼠遗传学和生物材料科学来改变HIF信号传导， 骨髓炎，并研究HIF对免疫反应和骨修复的影响。这些研究 将1）定义氧合在决定先天免疫和骨重建反应中的作用， 成骨细胞，2）定义成骨细胞HIF信号传导对抗菌免疫和骨修复的影响， S.金黄色骨髓炎，和3）测试HIF靶向治疗作为抗感染佐剂的潜力， 骨的侵入性感染。总的来说，这项建议将阐明如何氧合影响骨骼细胞 生物学和对细菌病原体的先天免疫反应，同时提供理想的培训和指导 发展我未来的职业生涯作为一个独立的调查员和医生科学家。