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

摘要摘要 我们已经证明了葡萄球菌中葡萄球菌辅助调节基因(SARA)的突变 金黄色葡萄球菌导致胞外蛋白酶的产生增加到限制生物被膜的程度 形成，限制对哺乳动物细胞的细胞毒性，包括成骨细胞和破骨细胞，并限制 表面相关毒力因子和胞外毒力因子的积累。我们也证明了 这可能与脓毒症和骨髓炎动物模型中毒力降低有关。此外，我们 已经证实所有这些表型在不同的金黄色葡萄球菌临床分离株中都很明显，而且他们 可以通过消除SARA突变体产生胞外蛋白酶的能力来逆转。在这份提案中， 我们将在这些观察的基础上扩展以确定特定的胞外蛋白水解酶 我们的基本科学假设在不同的金黄色葡萄球菌临床分离株(目标1)中的背景下，并使用 获得的信息，以询问这些蛋白酶对毒力因子谱系的影响 临床分离，确定SARA和这些蛋白酶对骨重建和宿主反应的影响 骨感染，并最终识别和评估单独的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).