Characterization of the mechanisms underpinning quorum sensing progression in Pseudomonas aeruginosa

铜绿假单胞菌群体感应进展机制的表征

基本信息

批准号：
10337557
负责人：
Jon E Paczkowski
金额：
$ 28.34万
依托单位：
WADSWORTH CENTER
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-03-01 至 2027-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10337557
关键词：
Affect Affinity Anti-Bacterial Agents Architecture Bacteria Behavior Binding Biochemical Biological Assay Carrier Proteins Cell Communication Cell Cycle Cell Density Cell Signaling Process Cells ChIP-seq Clinical Communication Communities Complex DNA DNA Binding DNA Binding Domain Data Deoxyribonucleases Detection Development Down-Regulation Environment Enzymes Gene Expression Gene Expression Profile Genes Genetic Transcription Goals Growth High-Throughput Nucleotide Sequencing Hydrolase In Vitro Infection Ligands Light Maps Mediating Medicine Microbial Biofilms Molecular Molecular Conformation Molecular Genetics Mutagenesis Mutation Organism Output Pathogenesis Phase Play Process Production Proteins Pseudomonas aeruginosa Pseudomonas aeruginosa infection Regulation Regulatory Element Regulon Reporter Role Shapes Signal Transduction Signal Transduction Pathway Signaling Molecule Specificity Structure System Techniques Therapeutic Time Transcriptional Regulation Up-Regulation Virulence Virulence Factors X-Ray Crystallography combat cost experimental study extracellular genetic approach human pathogen in vivo insight metalloenzyme microbial community novel pathogenic bacteria prevent promoter protein folding protein protein interaction quorum sensing receptor receptor binding response rhamnolipid surfactant trait transcription factor transcriptome sequencing

项目摘要

PROJECT SUMMARY Quorum sensing (QS) is a mechanism of cell-cell communication that bacteria use to orchestrate collective behaviors, including virulence and biofilm formation. QS relies on the production, release, and group- wide detection of extracellular signal molecules called autoinducers (AI). QS allows bacteria to synchronously alter gene expression patterns that underpin collective behaviors, for example, biofilm formation. Some receptors bind and respond exclusively to one AI, while others bind and respond to multiple AIs. QS is responsible for releasing public goods that are beneficial to kin and, potentially, non-kin, and as a result, it plays an important role in shaping microbial community architecture. QS is now understood to be the norm in the bacterial world. Nonetheless, how different bacterial QS receptors initiate signal transduction is not understood. Defining the mechanisms that regulate QS-mediated production of public goods will be key for generally understanding how organisms coordinate community level changes in gene expression. This is particularly important in light of our findings that P. aeruginosa QS can be activated by signals produced by non-kin. Thus, determining the mechanisms that regulate QS progression after signal recognition will allow us to understand the respective benefits and drawbacks of strict versus relaxed ligand detection in QS-mediated communication. Bacteria live in heterogeneous communities and encounter mixtures of AIs produced by themselves, their kin, and their non-kin neighbors. Upon signal recognition, LasR and RhlR activate hundreds of genes, many of which are involved in pathogenesis and biofilm formation. While some signal transduction pathways follow a linear circuit, the QS system in P. aeruginosa is best described as a dense network of receptors and regulators with interconnecting regulatory systems and outputs. Canonically, the LasR-AI complex activates expression of rhlR and rhlI, thus launching the second QS system, enabling the two QS systems to function in tandem. Surprisingly, rhlR can be upregulated in clinical isolates containing lasR inactivating mutations. RhlR can also function without its partner synthase to regulate certain genes. This is achieved via a metallo-hydrolase known as PqsE. We discovered that PqsE and RhlR interact to form a complex. We will explore the role of PqsE in regulating RhlR function and describe their tandem role in transcriptional regulation and pathogenesis in AIM 1. The progression into QS corresponds to a downregulation of certain regulatory elements that function at low cell density to potentially mitigate early entry into QS. We have discovered that Fis, which is expressed during log phase, regulates the production of rhlA, a gene responsible for the synthesis of rhamnolipids, which are a bacterial surfactant important for infections. We will explore the mechanism Fis uses to achieve this regulation, in addition to what role it might play in regulating other QS genes and behaviors in AIM 2.

项目概要群体感应 (QS) 是细菌用来协调细胞间通讯的一种机制集体行为，包括毒力和生物膜形成。 QS依赖于生产、发布、分组—— 广泛检测称为自诱导剂 (AI) 的细胞外信号分子。 QS让细菌同步改变支撑集体行为的基因表达模式，例如生物膜的形成。一些受体只对一个 AI 进行绑定和响应，而其他 AI 则对多个 AI 进行绑定和响应。 QS负责释放对亲属和潜在的非亲属有益的公共物品，因此发挥着重要作用在塑造微生物群落结构中的作用。 QS 现在被认为是细菌世界的常态。尽管如此，不同的细菌 QS 受体如何启动信号转导尚不清楚。定义调节 QS 介导的公共产品生产的机制将是普遍理解如何进行的关键生物体协调群落水平的基因表达变化。鉴于我们的情况，这一点尤其重要研究结果表明，铜绿假单胞菌 QS 可以被非亲属产生的信号激活。因此，确定信号识别后调节 QS 进展的机制将使我们能够了解各自的 QS 介导的通讯中严格与宽松的配体检测的优点和缺点。细菌生活在异质社区并遇到由他们自己、他们的亲属和非亲属产生的人工智能的混合物邻居。信号识别后，LasR 和 RhlR 激活数百个基因，其中许多基因参与发病机制和生物膜形成。虽然一些信号转导途径遵循线性电路，但 QS 铜绿假单胞菌系统最好的描述是一个由受体和调节因子组成的密集网络，这些网络相互连接监管体系和产出。通常，LasR-AI 复合物激活 rhlR 和 rhlI 的表达，因此启动第二个QS系统，使两个QS系统协同运作。令人惊讶的是，rhlR 可以在含有 lasR 失活突变的临床分离株中上调。 RhlR 也可以在没有其合作伙伴的情况下发挥作用合成酶来调节某些基因。这是通过称为 PqsE 的金属水解酶实现的。我们发现 PqsE 和 RhlR 相互作用形成复合物。我们将探讨 PqsE 在调节 RhlR 功能和描述它们在 AIM 1 转录调控和发病机制中的串联作用。 QS 的进展对应于某些在低细胞密度下发挥作用的调节元件的下调，以潜在地减少提前进入 QS 的情况。我们发现 Fis 在对数期表达，调节 rhlA 的产生，这是一种负责合成鼠李糖脂的基因，鼠李糖脂是一种细菌表面活性剂对于感染很重要。我们将探讨 Fis 实现这一监管的机制，除了什么它在调节 AIM 2 中其他 QS 基因和行为中可能发挥的作用。