Contribution of Spx to Staphylococcus aureus physiology and virulence

项目摘要/摘要 金黄色葡萄球菌是一种强大的人类病原体，因为它有大量的毒力因子，因此 感染人体任何部位的细菌。我们的长期目标是了解 金黄色葡萄球菌调节毒力因子的表达和活性，从而导致疾病。这包括揭开小说 毒力因子产生的途径和对环境变化的反应。Spx蛋白 被革兰氏阳性细菌用来调节基因表达，以应对二硫化物和氧化应激。多数 对Spx的了解源于对芽孢杆菌和链球菌的研究，只有少数研究 研究了Spx在金黄色葡萄球菌中的重要性。其中两项研究的解释受到阻碍，原因是 后来发现的次要位点突变。最近，我们发表了一项研究，其中包括一个SPX突变体 在临床相关的MRSA菌株的USA300谱系中。在这种背景下，SPX有助于在 联胺应激与色素的产生。SPX在金黄色葡萄球菌中是必不可少的，但可以通过控制 表达硫氧还蛋白，这是我们使用的技术。尽管产生硫氧还蛋白，但SPX突变体具有 生长缺陷。我们也有新的初步数据表明spx突变体改变了关键溶血素的活性。 分泌的蛋白质。生长缺陷和毒力因子产生变化的原因尚未得到证实 这是本应用程序的重点所在。 根据我们的初步数据，我们假设Spx调节新陈代谢和关键调控 控制毒力因子表达的网络。为了验证这一点，我们提出了三个目标。AIM 1使用RNAseq ChIPseq和靶向代谢组学，以确定Spx的调节子和Spx对新陈代谢的影响。AIM 2构建 根据我们的初步数据显示溶血素活性降低，以确定这种表型背后的机制。 这项研究使用突变体、记者和 定量分析。Aim 3首次用小鼠检测Spx对金黄色葡萄球菌毒力的影响 皮肤感染模型。此外，它还使用活体动物成像来检测体内毒力因子的表达。 这些研究的完成将为深入了解这种重要病原体的毒力因子调控提供依据。在……里面 此外，还首次确定了金黄色葡萄球菌中Spx的调节基因，并确定了Spx在金黄色葡萄球菌中的作用。 金黄色葡萄球菌的致死性。

PROJECT SUMMARY/ABSTRACT Staphylococcus aureus is a potent human pathogen due to its large repertoire of virulence factors, allowing this bacterium to infect any part of the human body. Our long-term goal is to understand the mechanisms by which S. aureus modulates virulence factor expression and activity to cause disease. This includes uncovering novel pathways contributing to virulence factor production and responses to environmental changes. The Spx protein in used by Gram-positive bacteria to regulate gene expression in response to disulfide and oxidative stress. Most of what is known about Spx stems from studies in Bacillus and Streptococcus and only a few studies have examined the importance of Spx in S. aureus. The interpretation of two of those studies are hampered due to secondary site mutations that were later discovered. Recently, we published a study that included an spx mutant in a clinically relevant MRSA strain of the USA300 lineage. In this background, Spx contributes to survival under diamide stress and pigment production. Spx is essential in S. aureus but can be circumvented by controlled expression of thioredoxin, a technique we employ. Despite thioredoxin production, the spx mutants have a growth defect. We also have new preliminary data that the spx mutant has altered activity of key hemolytic secreted proteins. The reason for the growth deficiency and altered virulence factor production has not been elucidated and is the focus of this application. Based on our preliminary data, we hypothesize that Spx modulates metabolism and key regulatory networks that control virulence factor expression. To test this, three aims are proposed. Aim 1 uses RNAseq ChIPseq, and targeted metabolomics to define the Spx regulon and impact of Spx on metabolism. Aim 2 builds on our preliminary data showing reduced hemolysin activity to identify the mechanism behind this phenotype. This examines key regulatory networks believed to be involved using a combination of mutants, reporters, and quantitative assays. Aim 3 tests for the first time the contribution of Spx to S. aureus virulence using a murine skin infection model. Furthermore, it uses live animal imaging to examine virulence factor expression in vivo. Completion of these studies will provide insight into virulence factor regulation in this important pathogen. In addition, it will be the first to define the Spx regulon in S. aureus and determine the contribution of Spx to S. aureus virulence.