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已经调查了S。 金黄色葡萄球菌胞外蛋白水解酶的致病作用。直到最近，这些数据被证明是不确定的， 然而，我们小组的工作已经明确地表明，分泌的蛋白酶是 金黄色葡萄球菌病。它们的作用似乎是双相的：i)分泌的蛋白酶缺失导联 受感染动物的超强毒力；而ii)完全没有蛋白酶的菌株已经损害了生存 在人类血液中，对吞噬的抵抗力降低，对AMPS的敏感性增加，并受损 在感染期间传播和/或存活的能力。对这些发现的解释源于 在感染过程中，由于它们不同的作用和底物。具体地说，增加的死亡率是 由越来越多的毒力因子驱动，这些毒力因子不受控制地存在于分泌物中 蛋白酶缺失。相反，毒力的减弱是由这些酶介导的。 攻击宿主，分解促进营养、免疫逃避和传播的蛋白质。 然而，尽管如此，关于这些酶是如何调节的，如何调控，仍然有很多未知之处 它们自己调节感染，以及它们如何增强金黄色葡萄球菌在体内的适合性。填写以下内容 我们将探索这些差距：1。金黄色葡萄球菌感染过程中分泌型蛋白水解酶的调节。 我们目前还不知道哪种酶能分解哪种毒力因子，也不知道这是如何影响的。 感染的进展。因此，在这个目标中，我们将在体外连接毒力因子蛋白分解 对体内金黄色葡萄球菌的致病潜能的影响。2.分泌型蛋白水解酶的调控 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(确实是)严格控制，以便调整毒力因子的丰度。 在疾病起因期间。因此，在这一目标中，我们将填补有关以下方面的主要知识空白 在体外分泌蛋白酶调节，并将其与体内发生的事情联系起来。3.政府部门的角色 金黄色葡萄球菌感染过程中分泌的蛋白水解酶。蛋白水解酶生物学的下一个前沿 病原菌的背景是对宿主降解穹顶(完整的一套 被细菌蛋白酶切割的宿主蛋白)。因此，在这个目标中，我们将使用尖端技术 蛋白质组学技术深入了解感染过程以及宿主与宿主的相互作用 病原体。通过这些研究，我们将确定直接控制金黄色葡萄球菌的具体途径 疾病，提供了一个独特的和详细的洞察分子事件发生在 感染。这将产生关于金黄色葡萄球菌致病机制的关键发现，有可能 用于下一代新型抗毒力疗法。

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.