Defining the role of post-translational regulation by extracellular proteases in the pathogenesis of Staphylococcus aureus osteomyelitis

摘要 摘要 我们已经证明葡萄球菌中的葡萄球菌辅助调节（sarA）突变 金黄色葡萄球菌导致细胞外蛋白酶的产生增加到限制生物膜的程度 形成，限制哺乳动物细胞（包括成骨细胞和破骨细胞）的细胞毒性，并限制 表面相关毒力因子和细胞外毒力因子的积累。我们还证明了 这可能与败血症和骨髓炎动物模型中毒力的降低有关。此外，我们 已证实所有这些表型在金黄色葡萄球菌的不同临床分离株中都很明显，并且它们 可以通过消除 sarA 突变体产生细胞外蛋白酶的能力来逆转。在这个提案中， 我们将扩展这些观察结果，以确定与以下情况最相关的特定细胞外蛋白酶： 我们在金黄色葡萄球菌的不同临床分离株中的基本科学假设的背景（目标 1）并使用 获得的信息用于询问这些蛋白酶对毒力因子库的影响 临床分离，定义 sarA 和这些蛋白酶对骨重建和宿主反应的影响 骨感染，最终识别和评估特定金黄色葡萄球菌毒力因子的贡献 并在这些表型上相互结合（目标 2）。

SUMMARY ABSTRACT We have demonstrated that mutation of the staphylococcal accessory regulatory (sarA) in Staphylococcus aureus results in an increase in the production of extracellular proteases to a degree that limits biofilm formation, limits cytotoxicity for mammalian cells including osteoblasts and osteoclasts, and limits the accumulation of both surface-associated and extracellular virulence factors. We have also demonstrated that this can be correlated with decreased virulence in animal models of sepsis and osteomyelitis. Moreover, we have confirmed that all of these phenotypes are evident in diverse clinical isolates of S. aureus and that they can be reversed by eliminating the ability of sarA mutants to produce extracellular proteases. In this proposal, we will expand on these observations to identify the specific extracellular proteases that are most relevant in the context of our underlying scientific hypothesis in diverse clinical isolates of S. aureus (Aim 1) and use the information gained to interrogate the impact of these proteases on the virulence factor repertoire on these clinical isolates, define the impact sarA and these proteases on bone remodeling and the host response in bone infection, and ultimately identify and evaluate the contribution of specific S. aureus virulence factors alone and in combination with each other on these phenotypes (Aim 2).