A New Quorum-Sensing Autoinducer Acts with the RhIR Receptor to Control Virulence and Biofilms in Pseudomonas Aeruginosa

一种新型群体感应自诱导剂与 RhIR 受体共同作用来控制铜绿假单胞菌的毒力和生物膜

基本信息

批准号：
10491535
负责人：
Sampriti Mukherjee
金额：
$ 2.05万
依托单位：
UNIVERSITY OF CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-01 至 2023-08-31
项目状态：
已结题

项目摘要

PROJECT SUMMARY Hospital-acquired secondary infections are an escalating problem of global significance. Indeed, multi-drug resistant Pseudomonas aeruginosa is the leading cause of hospital-acquired infections in the USA and P. aeruginosa is now a priority pathogen on the CDC ESKAPE pathogen list. P. aeruginosa infection is a particular problem in cystic fibrosis, microbial keratitis, in third-degree burn units, and in cancer sufferers and HIV patients. P. aeruginosa virulence and biofilm development depend on the bacterial cell-to-cell communication process called quorum sensing. The known P. aeruginosa quorum-sensing circuit possesses two canonical LuxI/R type signaling pathways: LasI/R and RhlI/R, that, together, control an estimated 10% of the genes in the genome. The known circuit functions as follows: LasI produces and LasR responds to the autoinducer 3OC12-homoserine lactone. The LasR:3OC12-homoserine lactone complex activates transcription of many genes including rhlR, encoding a second quorum-sensing receptor. RhlR binds to the autoinducer C4-homoserine lactone, the product of RhlI. RhlR:C4-homoserine lactone also directs a large regulon of genes including those encoding virulence factors such as pyocyanin, elastases, and rhamnolipids. Typically, mutations in quorum-sensing luxI-type and luxR-type genes (i.e., lasI-lasR and rhlI-rhlR) confer identical phenotypes because each component of the pair needs the other to function. However, using biofilm analyses, transcriptional reporter assays, RNA-seq studies, and animal infection assays, I discovered that RhlR directs both RhlI-dependent and RhlI-independent regulons. I discovered that an alternative autoinducer, synthesized by the PqsE thioesterase enzyme, drives the RhlI- independent RhlR regulon. I demonstrated that while the canonical RhlR-RhlI system is dispensable, the RhlR- PqsE system is the crucial quorum-sensing system required for biofilm formation and for virulence in two animal models of infection. Most importantly, these studies revealed that unlike LasR that activates biofilm formation, RhlR functions as a repressor of biofilm development. Here, I propose to determine (1) how Rhl quorum sensing converges with Cbr nutrient sensing system to repress biofilm formation and (2) what factors allow biofilm formation when the sensory cues for Las, Rhl and Cbr systems are absent. The proposed research will contribute a mechanistic understanding of quorum-sensing control of biofilm formation and uncover how quorum sensing intersects with other sensory signaling systems, which is crucial for understanding basic P. aeruginosa biology and for successful development of anti-quorum-sensing strategies.

项目摘要医院获得的继发感染是全球意义的不断升级问题。确实，多药抗性假单胞菌铜绿菌是美国和P.医院获得感染的主要原因。铜绿疾病现在是CDC Eskape病原体清单上的优先病原体。铜绿假单胞菌感染是一种特殊的囊性纤维化，微生物角膜炎，三级烧伤单位以及癌症患者和HIV患者的问题。铜绿假单胞菌毒力和生物膜发育取决于细菌细胞对细胞通信过程称为Quorum Sensing。已知的铜绿假单胞菌群体感应电路具有两种规范的卢克斯/R类型信号通路：LASI/R和RHLI/R，共同控制基因组中约有10％的基因。已知电路的作用如下：LASI产生和LASR对自动诱导剂3oc12-homoserine响应内酯。 LASR：3OC12-耶洛瑟内酯复合物激活许多基因的转录，包括RHLR，编码第二个群体感应受体。 RHLR与自动诱导剂C4-HOMOSERINE内酯结合，产品 Rhli。 RHLR：C4-耶洛塞林内酯也指导大量的基因调节，包括编码毒力的基因诸如化合物苷，弹性酶和鼠李糖脂等因素。通常，征服卢克斯型的突变和 luxR型基因（即lasi-lasr和rhli-rhr）赋予了相同的表型需要另一个才能起作用。但是，使用生物膜分析，转录报告基因测定，RNA-seq研究，和动物感染测定法，我发现RHLR指导RHLI依赖性和RHLI独立的调节剂。我发现，由PQSE硫酯酶合成的替代自动诱导剂驱动Rhli- 独立的RHLR Regulon。我证明，虽然规范的RHLR-RHLI系统是可置的，但Rhlr- PQSE系统是生物膜形成所需的至关重要的群体感应系统和两种动物的毒力感染模型。最重要的是，这些研究表明，与激活生物膜形成的LASR不同， RHLR充当生物膜发育的阻遏物。在这里，我建议确定（1）rhl Quorum如何传感与CBR营养感应系统收敛以抑制生物膜形成，（2）哪些因素允许生物膜当不存在LA，RHL和CBR系统的感觉提示时形成。拟议的研究将做出贡献对生物膜形成的群体感应控制的机械理解，并发现法定人数如何感应与其他感觉信号系统相交，这对于理解基本铜绿假单胞菌生物学至关重要并成功地制定了抗Quorum-Sensing策略。