Manipulating a Virulence Switch to Combat Acinetobacter baumannii Infections

鲍曼不动杆菌是一种医院内致病菌 退伍军人医院、民用医院和军队医院的感染人数。这项提议将 扩展我们实验室的新发现，在那里工作已经发现鲍曼不动杆菌细胞 可以存在于两个亚群中，一个是毒力的，一个是无毒的。这些 亚群可以迅速相互转换，我们已经确定了一个中央调节因子 这个开关的。该TetR型调节子由ABUW_1645基因编码， 该调节子的过表达将细胞从毒力状态驱动到无毒状态 说明它们现在被锁定的位置。之前的工作发现了一个复杂的监管 LysR型调节器(ABUW_1132)激活ABUW_1645的网络 表达和两个额外的TetR调节子，由ABUW_1959和 ABUW_2818，使细胞进入无毒状态。个体 ABUW_1959或ABUW_2818的过表达也会驱动毒力细胞 进入无毒状态，现在它们被锁定在那里。这一点的认定 控制毒力的开关和我们对其调节的理解现在为 翻译干预利用这种开关并使细胞无毒的方法。 首先，我们将确定由所有三个监管机构控制的基因，这些基因有助于 毒力丧失。这些基因的作用将通过构建 适当的突变和在动物模型中的测试。接下来，我们将利用 开发鲍曼不动杆菌减毒活疫苗 紧张。最后，将细胞从有毒细胞驱动到无毒细胞的小分子 将通过高通量筛选来识别状态。最终，这些抑制物 可能导致开发新的治疗方法来消除这种病毒的毒性 日益重要的细菌病原体。

Acinetobacter baumannii is a nosocomial pathogen responsible for an increasing number of infections in VA, civilian and military hospitals. This proposal will extend novel findings in our lab, where work has identified that A. baumannii cells can exist in two subpopulations, one virulent and one avirulent. These subpopulations can rapidly interconvert and we have identified a central regulator of this switch. This TetR-type regulator is encoded by the ABUW_1645 gene and overexpression of this regulator drives cells from the virulent state to the avirulent state where they are now locked. Previous work identified a complex regulatory network where a LysR-type regulator (ABUW_1132) activates ABUW_1645 expression and two additional TetR regulators, encoded by ABUW_1959 and ABUW_2818, which drives cells into the avirulent state. Individual overexpression of either ABUW_1959 or ABUW_2818 also drives virulent cells into an avirulent state, where they are now locked. The identification of this switch controlling virulence and our understanding of its regulation now paves the way for translational interventions to exploit this switch and render cells avirulent. First, we will identify genes controlled by all three regulators that contribute to the loss of virulence. The role of these genes will be tested by constructing the appropriate mutants and testing in animal models. Next, we will take advantage of the locked avirulent state to develop a live attenuated A. baumannii vaccine strain. Lastly, small molecules that drive cells from the virulent to the avirulent state will be identified by high-throughput screening. Ultimately, these inhibitors may result in the development of novel therapies to disable virulence in this increasingly important bacterial pathogen.