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。 地球仪。这在很大程度上是由于多重耐药性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，有一个重要的 需要开发针对该生物体的有效治疗剂。在我们的研究中， 了解S.金黄色葡萄球菌在不同环境中对该病原体的影响 在体外和宿主体内的毒力。因此，我们的长期目标是阐明S。aureus接收 来自宿主环境的信号（例如氧浓度、营养物），感测其自身的氧化还原平衡， 能量状态，并触发代谢变化，包括毒力因子的产生。 我们以前的研究确定了两种呼吸酶在S。称为2型NADH脱氢酶的金黄色葡萄球菌 （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， 毒力因子的产生和体外生物膜的形成。这些结果导致我们的中心假设， 依赖于NADH的呼吸链主要负责控制NADH/NAD+和MQH 2/MQ （甲萘醌/甲萘醌）池，由细胞用来监测其氧化还原状态，我们建议 是通过特定的全球调节器调节毒力的主要因素。根据初步数据，我们 我建议追求三个具体的目标：（1）确定代谢途径利用的存在 以及两种NADH脱氢酶中的每一种的缺乏，以及 这些酶调节α-毒素的产生;（2）确定为什么两种NADH的存在 脱氢酶对于生物膜形成是重要的;（3）确定甲萘醌是否是生物膜形成的信号传导。 在SaeRS和SrrAB双组分中直接诱导SrrB和SaeS自激酶活性的分子 系统，这两者都是至关重要的毒力和生物膜形成的调节。为了实现这些目标， 我们已经组建了一个强大的团队，采用多学科的方法，结合代谢组学， 蛋白质组学、遗传学、微流体技术和生物化学。 总的来说，我们提出的研究将通过揭示 呼吸链在连接环境信号与细胞内的氧化还原平衡，调节S。金黄色 毒性从长远来看，这些研究可能揭示新的治疗靶点，以治疗S。金色相关 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.