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

摘要 我们已经证明，葡萄球菌中葡萄球菌辅助调节基因（sarA）突变 金黄色葡萄球菌导致胞外蛋白酶的产生增加到限制生物膜的程度 形成，限制了对哺乳动物细胞包括成骨细胞和破骨细胞的细胞毒性，并限制了细胞毒性。 表面相关和细胞外毒力因子的积累。我们还证明， 这可能与脓毒症和骨髓炎动物模型中的毒力降低有关。而且我们 已经证实，所有这些表型在不同的临床分离的沙门氏菌中是明显的。金黄色葡萄球菌， 可以通过消除sarA突变体产生胞外蛋白酶的能力来逆转。在这一提议中， 我们将在这些观察的基础上进行扩展，以确定与细胞外蛋白酶最相关的特异性细胞外蛋白酶。 我们在不同临床分离的S.金黄色葡萄球菌（目标1），并使用 获得的信息来询问这些蛋白酶对这些病毒的毒力因子库的影响， 临床分离物，定义sarA和这些蛋白酶对骨重建的影响以及在 骨感染，并最终确定和评估的贡献，具体的S。单独的金黄色葡萄球菌毒力因子 并相互结合对这些表型的影响（目的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).