Elucidating Pseudomonas aeruginosa non-canonical two component system signaling

阐明铜绿假单胞菌非典型二组分系统信号传导

• 批准号: 8224251
• 负责人: DEBORAH T HUNG
• 金额: $ 26.19万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-03-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8224251
• 关键词: Acute; Antibiotic Resistance; Antibiotics; Attention; Bacteria; Bacterial Proteins; Biochemical; Biochemical Genetics; Candidate Disease Gene; Chronic; Clinical; Complex; Development; Disease; Embryo; Environment; Evaluation; Event; Genes; Genetic; Genetic Suppression; Growth; Health; Human; In Vitro; Infection; Life Style; Mediating; Modeling; Molecular; Molecular Profiling; Phenocopy; Phenotype; Phosphorylation; Phosphotransferases; Play; Prevalence; Process; Proteins; Pseudomonas aeruginosa; Reporter; Role; Screening procedure; Signal Transduction; System; Testing; Therapeutic; Validation; Virulence; Zebrafish; candidate identification; combat; genetic selection; in vivo; inhibitor/antagonist; insight; mutant; novel; novel strategies; novel therapeutics; pathogen; protein-histidine kinase; response; sensor; sensor histidine kinase

DESCRIPTION (provided by applicant): The increasing prevalence of antibiotic resistance among clinically important pathogens is a growing threat, outpacing the development of antibiotics with new mechanisms of action. One novel approach that has drawn increasing attention is targeting bacterial virulence. One attractive class of targets is two component systems (TCSs), which sense changes in the environment and coordinate a cellular response. These bacterial targets are important during infection while absent in mammalian hosts. Moreover, TCSs are often conserved across species so that inhibitors would have the potential to be broad spectrum in activity. Pseudomonas aeruginosa, an important clinical pathogen with increasing antibiotic resistance, encodes one of the largest sets of TCSs known in bacteria and is thought to use these TCSs to coordinate the transition between growth in the external environment and in a human host, including the transition from acute to chronic infection lifestyles. It is becoming increasingly clear that TCS signaling is highly complex in P. aeruginosa. While canonical TCS signaling, defined as phosphorylation of a response regulator by its cognate histidine sensor kinase, is important, increasing evidence suggests that non-canonical TCS signaling may be equally important. Non-canonical signaling includes a number of different signaling mechanisms such as 1. physical interactions between sensors rather than phosphorylation events to modulate the activity of a response regulator, 2. signaling of a sensor through an alternative response regulator, or 3. signaling through multiple response regulators by one sensor kinase (cross-talk). We have identified several novel TCS not previously known to play a role in acute infection by screening a comprehensive set of P. aeruginosa mutants in 58 TCS sensor kinases in a new vertebrate model of acute infection. We identified kinB, phoR, bqsS, and copS as being required for full virulence in Danio rerio (zebrafish) embryos as well as gacS and retS, which have previously been shown to be required for infection in other models. We found that while KinB is required for acute infection, it signals non-canonically, independent both of its cognate response regulator, AlgB, and of its kinase activity. We propose to elucidate the mechanism of KinB's non-canonical TCS signaling and define the degree of non-canonical TCS signaling for the three other novel TCS (PhoR, BqsS, and CopS). Understanding the extent of non-canonical TCS signaling and the degree of cross-talk among TCS sensors and response regulators during acute vertebrate infection is critical for evaluating the potential of targeting TCS as a therapeutic strategy and will provide insight into the mechanisms that pathogens use to adapt to varying environments, including the human host to elicit disease. PUBLIC HEALTH RELEVANCE: Understanding how bacterial pathogens such as Pseudomonas aeruginosa sense and respond to their environments, including the human host, is critical to understanding how they adapt to the host microenvironment and cause disease. We have identified several Pseudomonas aeruginosa signaling systems called two component systems that are required to cause lethality in a vertebrate host model. We propose to elucidate the mechanisms by which they transduce these signals through intracellular response regulators; therefore, by understanding such molecular processes, we will evaluate the potential new paradigm of targeting such bacterial factors as a new therapeutic strategy in this current era of increasing antibiotic resistance.

描述(由申请人提供)：临床重要病原体中抗生素耐药性的日益流行是一个日益增长的威胁，超过了具有新作用机制的抗生素的发展。一种引起越来越多关注的新方法是瞄准细菌的毒力。两组分系统(TCS)是一类很有吸引力的靶标，它可以感知环境的变化并协调细胞反应。这些细菌靶标在感染期间是重要的，而在哺乳动物宿主中则不存在。此外，TCS通常在物种之间是保守的，因此抑制剂可能具有广谱的活性。 铜绿假单胞菌是一种重要的临床病原菌，对抗生素的耐药性日益增加，它编码了已知的细菌中最大的TCS之一，并被认为使用这些TCS来协调外部环境和人类宿主之间的生长过渡，包括从急性感染到慢性感染的生活方式的转变。越来越清楚的是，TCS信号在铜绿假单胞菌中是高度复杂的。虽然典型的TCS信号是重要的，但越来越多的证据表明，非规范的TCS信号可能也同样重要。非规范信号包括许多不同的信号机制，如1.传感器之间的物理相互作用而不是调节反应调节器活性的磷酸化事件，2.通过另一种反应调节器发出传感器信号，或3.通过一个传感器激酶通过多个响应调节器发出信号(串扰)。 在一种新的脊椎动物急性感染模型中，我们通过筛选58个TCS感应器激酶中的一组完整的铜绿假单胞菌突变体，鉴定了几个以前未知的在急性感染中发挥作用的新的TCS。我们发现，在斑马鱼(Danio Rerio)胚胎以及GAC和RET中，kinB、phor、bqsS和COPS是完全毒力所必需的，此前在其他模型中，它们被证明是感染所必需的。我们发现，虽然急性感染需要KinB，但它的信号不是典型的，不依赖于它的同源反应调节因子ALB，也不依赖于它的激酶活性。我们建议阐明KinB的非典范TCS信号的机制，并定义其他三个新的TCS(PHOR、BQS和COPS)的非典范TCS信号的程度。了解急性脊椎动物感染期间TCS信号的非规范程度以及TCS传感器和反应调节器之间的串扰程度，对于评估将TCS作为治疗策略的潜力至关重要，并有助于深入了解病原体用来适应不同环境的机制，包括引发疾病的人类宿主。 公共卫生相关性：了解铜绿假单胞菌等细菌病原体如何感知和响应其环境，包括人类宿主，对于了解它们如何适应宿主微环境并导致疾病至关重要。我们已经确定了几个铜绿假单胞菌信号系统，称为两个组件系统，这是导致脊椎动物宿主模型致死所必需的。我们建议阐明它们通过细胞内反应调节因子传递这些信号的机制；因此，通过了解这些分子过程，我们将评估在当前抗生素耐药性增加的时代，针对这些细菌因子作为新治疗策略的潜在新范例。