Investigating the role of conserved signaling modules in medically important Acinetobacter species

项目摘要 医学上重要的不动杆菌属是机会性细菌病原体，其可引起 在住院患者中是毁灭性的疾病，在美国约占医院感染的2%。 这些物种正在成为世界范围内的公共卫生威胁，因为它们倾向于表现出多药，或 甚至是泛耐药性。因此，我们迫切需要开发新的治疗和预防MDR的方法 不动杆菌感染。这一进展的关键是详细了解这些物种如何导致人类 然而，关于不动杆菌属感染的发病机制仍有许多有待了解。重要的是， 恩格尔实验室和其他人已经确定了铜绿假单胞菌中的三个系统，另一个重要的系统是 条件致病菌，其响应于表面接触而协同激活毒力程序。这些 这些系统包括IV型菌毛（TFP）、Chp化学感受系统和cAMP/Vfr轴。所有这些 这些模块调节抽搐运动和>200个毒力基因的表达，例如II型分泌系统。 令人感兴趣的是，铜绿假单胞菌重新利用并将三个不同的模块组合在一起来调节急性 在其他细菌中，TFP和cAMP/Vfr轴控制其他过程。来测试是否 其他细菌利用类似的组件和类似的电路，恩格尔实验室进行了生物信息学分析， 以确定这些模块是否在其他细菌中保守并一起存在。高息 是发现医学上重要的不动杆菌属物种编码所有这三个模块的同源物。 鉴于不动杆菌属和铜绿假单胞菌的生活方式非常相似，包括它们的能力， 为了在不同的环境中生存，以及在人类中引起类似的疾病，我假设这三个 系统协调地起作用以调节致病性不动杆菌属物种在不同环境中存活的能力。 环境和人类疾病。在目标1中，我将使用细菌遗传学，生物化学， 和创新的显微镜分析，以建立不动杆菌Chp系统的功能输出， 确定它是否与TFP和cAMP/Vfr模块互连。在目标2中，我将使用转录组学 鉴定由不动杆菌Vfr转录调节因子调节的毒力基因的技术， 阐明Vfr激活是否取决于TFP和Chp系统模块。综合考虑，这些目标将使 我来确定TFP，Chp化学感受系统和cAMP/Vfr模块是否一起工作， 调节不动杆菌属物种的毒力。这些研究可能会发现新的靶点，以开发新的抗生素， 它们也可能提供对生理学和细胞生物学的更好的理解， 不动杆菌属。

Project summary Medically important Acinetobacter species are opportunistic bacterial pathogens that can cause devastating disease in hospitalized patients and are responsible for ~2% of nosocomial infections in the US. These species are emerging as a public health threat worldwide due to their tendency to exhibit multidrug-, or even, pandrug-resistance. Therefore, we urgently need to develop new methods to treat and prevent MDR Acinetobacter infections. Critical for this advance is a detailed understanding of how these species cause human disease; however, much remains to be learned about the pathogenesis of Acinetobacter infections. Importantly, The Engel lab and others have identified three systems in Pseudomonas aeruginosa, another important opportunistic pathogen, that coordinately activate a virulence program in response to surface contact. These systems include the type IV pilus (TFP), the Chp chemosensory system, and the cAMP/Vfr axis. Together, these modules regulate twitching motility and expression of >200 virulence genes, such as the type II secretion system. It is intriguing that P. aeruginosa repurposed and combined together three distinct modules to regulate an acute virulence program when in other bacteria the TFP and the cAMP/Vfr axis control other processes. To test whether other bacteria utilize similar components and similar circuitry, the Engel lab performed a bioinformatics analysis to determine whether these modules were conserved and present together in other bacteria. Of high interest was the finding that medically important Acinetobacter species encode homologs of all three of these modules. Given the remarkable similarity in the lifestyles of Acinetobacter species and P. aeruginosa, including their ability to survive in diverse environments as well as to cause similar diseases in humans, I hypothesize that these three systems function coordinately to regulate the ability of a pathogenic Acinetobacter species to survive in diverse environments and to cause human disease. In Aim 1, I will use a combination of bacterial genetics, biochemical, and innovative microscopy assays to establish the functional outputs of the Acinetobacter Chp system and to determine if it is interconnected to the TFP and cAMP/Vfr modules. In Aim 2, I will make use of transcriptomic technologies to identify the virulence genes regulated by the Acinetobacter Vfr transcriptional regulator and to elucidate if Vfr activation depends on the TFP and Chp system modules. Taken together, these aims will allow me to determine whether the TFP, the Chp chemosensory system, and the cAMP/Vfr modules work together to regulate virulence in Acinetobacter species. These studies may identify new targets to develop novel antibiotics, and they might also provide a better understanding of the physiology and cell biology of medically important Acinetobacter species.