The molecular mechanism linking respiratory NADH oxidation and virulence in Staphylococcus aureus

摘要 金黄色葡萄球菌感染是美国和全世界发病率和死亡率的主要原因 环球网。这在很大程度上是由于多重耐药的进化和细菌的适应能力。 它的新陈代谢和生物能量学几乎感染了人体的每一个部位。因此，有一个显著的 需要开发有效的治疗方法来对抗这种微生物。我们有几个关键的差距 金黄色葡萄球菌在不同环境中使用的代谢途径如何影响这种病原体的知识 在体外和宿主体内的毒力。因此，我们的长期目标是阐明金黄色葡萄球菌是如何接受 来自寄主环境的信号(如氧气浓度、营养物质)，感觉自己的氧化还原平衡和 能量状态，并触发新陈代谢变化，包括产生毒力因子。 我们以前的研究在金黄色葡萄球菌中发现了两种呼吸酶，称为2型nadh脱氢酶。 (NDH-2S：NdhC和NdhF)，并揭示了它们对动物感染和器官定植的重要性，以及 毒力因子的产生和体外生物被膜的形成。这些结果导致了我们的中心假设 依赖NADH的呼吸链主要负责控制NADH/NAD和MQH2/MQ (Menaquinol/Menaquinone)池，由细胞用来监控其氧化还原状态，我们建议 是通过特定的全球监管机构调节毒力的主要因素。在强劲的初步数据指引下，我们 建议追求三个具体目标：(1)确定在存在的情况下利用的代谢途径 以及两种NADH脱氢酶各自的缺失及其分子机制。 这些酶调节α毒素的产生；(2)确定为什么两种NADH的存在 脱氢酶对于生物膜的形成是重要的；(3)确定脑啡醇是否是信号转导。 直接诱导SaeRS和SrrAB双组分中的SrrB和SAES自激酶活性的分子 系统，这两个都是关键的毒力调节和生物膜的形成。为了实现这些目标， 我们已经组建了一个强大的团队，采用了结合新陈代谢学的多学科方法， 蛋白质组学、遗传学、微流体技术和生物化学。 总而言之，我们拟议的研究将通过揭示 连接环境信号与调节金黄色葡萄球菌的细胞内氧化还原平衡的呼吸链 致命性。从长远来看，这些研究可能揭示治疗金黄色葡萄球菌相关的新的治疗靶点。 疾病。

ABSTRACT Staphylococcus aureus infections are a major cause of morbidity and mortality in the United States and across the globe. This is largely due to the evolution of multidrug-resistance and the ability of the bacterium to adapt its metabolism and bioenergetics to infect nearly every site of the human body. Thus, there is a significant need for the development of effective therapeutics against this organism. There are several critical gaps in our knowledge of how metabolic pathways used by S. aureus in different environments influence this pathogen virulence in vitro and inside the host. Therefore, our long-term goal is to elucidate how S. aureus receives signals from the environment in the host (e.g. oxygen concentration, nutrients), senses its own redox poise and energy status, and triggers metabolic changes, including the production of virulence factors. Our previous studies identified two respiratory enzymes in S. aureus called type 2 NADH dehydrogenases (NDH-2s: NdhC and NdhF) and revealed their importance for animal infection and organ colonization, and the production of virulence factors and biofilm formation in vitro. These results lead to our central hypothesis that the NADH-dependent respiratory chain is primarily responsible for controlling the NADH/NAD+ and MQH2/MQ (menaquinol/menaquinone) pools that are used by the cell to monitor its redox status and which we propose are major elements regulating virulence via specific global regulators. Guided by strong preliminary data, we propose to pursue three Specific Aims: (1) Determine the metabolic pathways utilized both in the presence and absence of each of the two NADH dehydrogenase enzymes, and the molecular mechanisms by which these enzymes modulate the production of α-toxin; (2) Determine why the presence of both NADH dehydrogenase enzymes is important for biofilm formation; (3) Determine if menaquinol is the signaling molecule that directly induces SrrB and SaeS autokinase activity in the SaeRS and SrrAB two-component systems, which are both critical for the regulation of virulence and biofilm formation. To accomplish these Aims, we have assembled a powerful team to employ a multidisciplinary approach that combines metabolomics, proteomics, genetics, microfluidics technology and biochemistry. Collectively, our proposed studies will have a broad impact on the field by uncovering the role of the respiratory chain in connecting environment signals with the intracellular redox poise that regulates S. aureus virulence. In the long term, these studies may reveal novel therapeutic targets to treat S. aureus-related diseases.