The Role and Regulation of Extracellular Proteases in Staphylococcus aureus

摘要 我们和其他人进行的一些研究调查了S。 金黄色葡萄球菌胞外蛋白酶的致病作用。直到最近，这些数据都被证明是不确定的， 然而，我们小组工作已经明确表明分泌的蛋白酶是 S.金黄色葡萄球菌病它们的作用似乎是双相的：i）分泌型蛋白酶缺失导致 感染动物中的高毒力;而ii）完全蛋白酶无效菌株的存活受损 在人血液中，对吞噬作用的抵抗力降低，对AMP的敏感性增加， 在感染期间传播和/或存活的能力。对这些发现的解释源于 它们在感染过程中的不同作用和底物。具体来说，死亡率的增加是 由大量增加的毒力因子驱动，这些毒力因子在分泌后不受抑制地存在， 蛋白酶缺失相反，毒力衰减是由这些酶介导的 攻击宿主，切割蛋白质，促进营养，免疫逃避和传播。 然而，尽管如此，关于这些酶是如何调节的， 它们自身调节感染，以及它们如何增强S.金黄色葡萄球菌。填写 我们将探讨这些差距：1。分泌型蛋白酶对S.金黄色葡萄球菌感染 我们目前还不知道哪些蛋白酶切割哪些毒力因子，或者这如何影响 感染的进展。因此，在这个目标中，我们将连接体外毒力因子蛋白水解 S.的致病潜力。金黄色葡萄球菌。2.分泌性蛋白酶在细胞分裂中的调节 S.金黄色葡萄球菌感染虽然分泌的蛋白酶与毒力因子一起产生，但它们的 合成必须（实际上也是）严格控制，以调整毒力因子的丰度 在疾病的起因。因此，在这一目标中，我们将填补以下方面的主要知识空白： 分泌的蛋白酶调节，并将其与体内发生的事情联系起来。3.的作用 S.金黄色葡萄球菌感染蛋白酶生物学的下一个前沿领域是 病原菌的背景是对宿主降解组（完整的 由细菌蛋白酶切割的宿主蛋白质）。因此，在这一目标，我们将使用尖端 蛋白质组学技术，以深入了解感染过程，以及宿主与 病原体通过这些研究，我们将确定直接控制S的具体途径。金黄色 疾病，提供了一个独特的和详细的洞察分子事件发生期间， 感染这将产生关于S的关键发现。金黄色葡萄球菌的发病机制，有可能是 用于新一代的基于抗病力的治疗剂。

Abstract A number of studies performed by ourselves and others have investigated the contribution of S. aureus extracellular proteases to disease causation. Until recently, these data proved inconclusive, however work by our group has definitively shown that secreted protease are key mediators of S. aureus disease. Their role appears to be biphasic as: i) Secreted protease deletion leads hypervirulence in infected animals; whilst ii) A complete protease-null strain has impaired survival in human blood, decreased resistance to phagocytosis, increased sensitivity to AMPs and impaired ability for dissemination and/or survival during infection. An explanation for these findings stems from their differing roles, and substrates, during infection. Specifically, the enhanced mortality is driven by an increased abundance of virulence factors, which exist unchecked upon secreted protease deletion. Conversely, the virulence attenuation is mediated by these enzymes attacking the host, cleaving proteins that facilitate nutrition, immune evasion, and dissemination. However, despite this, much remains unknown about how these enzymes are regulated, how they themselves regulate infection, and how they enhance the fitness of S. aureus in vivo. To fill in these gaps we will explore: 1. Regulation by Secreted Proteases During S. aureus Infection. We currently do not know which proteases cleave which virulence factors, or how this influences the progression of infection. As such, in this aim we will connect in vitro virulence factor proteolysis to the pathogenic potential of S. aureus in vivo. 2. The Regulation of Secreted Proteases During S. aureus Infection. Although secreted proteases are produced alongside virulence factors, their synthesis must be (and indeed is) tightly controlled, so as to tailor virulence factor abundance during disease causation. Accordingly, in this aim we will fill in major knowledge gaps regarding secreted protease regulation in vitro, and connect this to what happens in vivo. 3. The Role of Secreted Proteases During S. aureus Infection. The next frontier of protease biology in the context of pathogenic bacteria is an understanding of the host degradome (the complete set of host proteins cleaved by bacterial proteases). Therefore, in this aim we will use cutting edge proteomic techniques to gain insight into the infectious process, and interaction of host with pathogen. Through these studies we will define specific pathways that directly govern S. aureus disease, providing a unique and detailed insight into the molecular events that occur during infection. This will produce key findings regarding S. aureus pathogenesis that has potential to be used for the future generation of novel anti-virulence based therapeutics.