Imaging the struggle for nutrient metal between host and pathogen

描述(申请人提供)：所有细菌病原体必须在其宿主内获得营养金属才能定居和致病。脊椎动物通过进化高亲和力的金属结合蛋白来利用这一要求，这种结合蛋白可以隔离金属，并在一种被称为“营养免疫”的过程中阻止细菌生长。为了与营养免疫竞争，细菌感知金属水平的变化，并协调基因表达的变化，使其能够适应这种环境通量。虽然在体外已经描述了对金属水平变化做出反应而激活的细菌调节电路，但细菌在脊椎动物感染期间何时何地经历金属应激尚不清楚。此外，促进营养免疫的宿主蛋白的完整目录尚未确定。在本应用程序中，我们建议通过应用 金黄色葡萄球菌感染小鼠模型的多模式成像方法。之所以选择金黄色葡萄球菌进行这些实验，是因为它是美国感染的主要原因，我们的实验室在葡萄球菌全身感染、骨髓炎和肺炎的小鼠模型中经验丰富。这些感染模型的多样性将提供有关营养免疫对不同部位感染的贡献的有价值的信息。 为了获得宿主和病原体之间争夺金属的全动物三维图像，小鼠将感染金黄色葡萄球菌，并随后接受一系列不同的成像方式。为了观察感染后整个动物的解剖变化，我们将使用磁共振成像(MRI)和计算机断层扫描(CT)。为了确定细菌金属依赖基因在感染动物体内的表达，我们将使用体内生物发光成像(BLI)。为了研究感染对整个动物体内蛋白质和元素丰度和分布的影响，我们将使用我们最近开创的用于研究传染病的成像质谱学(IMS)。从这些成像模式中获得的数据将使用我们最近开发的计算分析工具共同配准成单一的三维图像。这些数据结合在一起，将定义感染对金属蛋白分布和金属丰度的影响，并确定细菌如何对这些变化做出反应。这些数据将为合理设计针对营养性金属获取的治疗方法奠定基础。此外，作为这些实验的结果而开发的技术将适用于所有可以用动物模型研究的生理相关过程。

DESCRIPTION (provided by applicant): All bacterial pathogens must acquire nutrient metals within their hosts in order to colonize and cause disease. Vertebrates have taken advantage of this requirement by evolving high-affinity metal binding proteins that sequester metals and prevent bacterial growth in a process known as "nutritional immunity". To compete with nutritional immunity, bacteria sense alterations in metal levels and coordinate gene expression changes that enable adaptation to this environmental flux. Although the bacterial regulatory circuits that are activated in response to altered metal levels have been described in vitro, when and where bacteria experience metal stress during vertebrate infection is not known. In addition, the complete catalogue of host proteins that contribute to nutritional immunity has not been defined. In this application, we propose to fill these gaps in knowledge through the application of multi-modal imaging modalities to murine models of Staphylococcus aureus infection. S. aureus is chosen for these experiments because it is the leading cause of infection in the United States and our laboratory is experienced in murine models of staphylococcal systemic infection, osteomyelitis, and pneumonia. The diversity of these infection models will provide valuable information regarding the contribution of nutritional immunity to infection at a variety of distinc sites. To achieve a whole-animal three-dimensional image of the struggle for metal between host and pathogen, mice will be infected with S. aureus and sequentially subjected to a series of distinct imaging modalities. To observe anatomical changes that occur in whole animals following infection, we will employ magnetic resonance imaging (MRI) and computed tomography (CT). To define bacterial metal-dependent gene expression within infected animals we will use in vivo bioluminescence imaging (BLI). To study the impact of infection on protein and elemental abundance and distribution within whole animals, we will use imaging mass spectrometry (IMS) which we have recently pioneered for the study of infectious diseases. Data obtained from each of these imaging modalities will be co-registered into a single three-dimensional image using computational analysis tools that we have recently developed. Combined, these data will define the impact of infection on metalloprotein distribution and metal abundance and determine how bacteria respond to these changes. These data will lay the foundation for the rational design of therapeutics that target nutrient metal acquisition. In addition, the technologies developed as a result of these experiments will be applicable to all physiologically relevant processes that can be studied using animal models.