Determining the role of dialog between pathogenic streptococci in biofilm develop

确定致病性链球菌之间的对话在生物膜形成中的作用

• 批准号: 8837398
• 负责人: Laura Carol Case Cook
• 金额: $ 5.24万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-03-16 至 2017-03-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8837398
• 关键词: Affect; Animals; Candidate Disease Gene; Cell Communication; Cells; Communication; Complement; Data; Development; Disease; Future; Gene Deletion; Gene Expression; Gene Expression Profile; Genes; Goals; Growth; Homologous Gene; Human; In Vitro; Infection; Knock-out; Luciferases; Measures; Mediating; Microbial Biofilms; Modeling; Molecular Target; Monitor; Morbidity - disease rate; Mus; Mutation; Organism; Pathway interactions; Peptide Signal Sequences; Peptides; Phenotype; Pheromone; Production; Proteins; Regulation; Reporter; Research; Role; Signal Transduction; Streptococcal Infections; Streptococcus; Streptococcus Group B; Streptococcus pyogenes; System; Testing; Vagina; Virulence; Virulence Factors; base; clinically relevant; co-infection; gene replacement; human morbidity; human mortality; in vivo; inhibitor/antagonist; insight; mortality; mouse model; mutant; novel; novel therapeutics; pathogen; prevent; public health relevance; quorum sensing; research study

DESCRIPTION (provided by applicant): This project aims to characterize an overlapping bacterial quorum sensing (QS) system between Streptococcus pyogenes (Group A Streptococcus, GAS) and Streptococcus agalactiae (Group B Streptococcus, GBS) and the role of this system in biofilm formation and virulence. Both GAS and GBS are important human pathogens causing a variety of diseases, often biofilm related, and leading to significant human morbidity and mortality. Understanding communication between them will allow development of novel QS inhibitors to modulate virulence of both organisms. In GAS, the QS signaling peptides Shp2 and Shp3 enhance biofilm formation. These Shp peptides are regulated by two Rgg regulators, Rgg2/Rgg3 which, in turn, are regulated by the Shp peptides. In GBS, a small hydrophobic peptide (shp) almost identical to Shp2 has been found directly adjacent to a homolog almost identical to Rgg2 termed RovS. RovS has been shown to be a regulator of a multitude of virulence genes in GBS. Our preliminary data demonstrate that the production of the Shp by GBS can activate Shp2/3 regulated genes in GAS signifying interspecies communication between GAS and GBS via this QS system. The observed role of these QS systems in biofilm formation and virulence as well as their ability to mediate cross-species signaling clearly demonstrates the importance of understanding their mechanism of action. The results of these experiments may provide novel targets for QS inhibitors to prevent biofilm formation and decrease morbidity and mortality associated with streptococci infections. To examine the role of QS and interspecies communication between GAS and GBS on virulence and biofilm formation, we will create strains of GBS without RovS and/or the Shp peptide and use both luciferase reporters and qRT-PCR to measure gene expression in knockout strains. We will also make gene replacement strains swapping Rgg2 and RovS between GAS and GBS to determine whether these proteins can complement each other. Because Shp2/3 have been shown to enhance biofilm formation in GAS, the effects that each mutant has in biofilm development will be tested. To determine how peptide expression overlaps with biofilm formation, we will use RNASeq to determine the transcriptome profiles of GAS and GBS growing planktonically or in biofilms, and with or without the presence of the Shp peptide. Finally, we will test whether deletion of these genes alters the virulence of both GAS and GBS in mouse models of infection and carriage. Taken together, these studies will provide great insight into the ability of two important human pathogens to communicate with each other in clinically relevant settings. The data from mutational studies will allow us to characterize the first signaling system that allows communication between different species of streptococci.

描述（由申请人提供）：该项目旨在描述化脓性链球菌（A 组链球菌，GAS）和无乳链球菌（B 组链球菌，GBS）之间重叠的细菌群体感应（QS）系统的特征，以及该系统在生物膜形成和毒力中的作用。 GAS 和 GBS 都是重要的人类病原体，可引起多种疾病，通常与生物膜相关，并导致显着的人类发病率和死亡率。了解它们之间的通讯将有助于开发新型 QS 抑制剂来调节两种生物体的毒力。 在 GAS 中，QS 信号肽 Shp2 和 Shp3 增强生物膜形成。这些Shp 肽受两个Rgg 调节因子Rgg2/Rgg3 调节，而Rgg2/Rgg3 又受Shp 肽调节。在 GBS 中，已发现与 Shp2 几乎相同的小疏水肽 (shp) 直接邻近与 Rgg2 几乎相同的同源物（称为 RovS）。 RovS 已被证明是 GBS 中多种毒力基因的调节因子。我们的初步数据表明，GBS 产生的 Shp 可以激活 GAS 中的 Shp2/3 调节基因，这意味着 GAS 和 GBS 之间通过该 QS 系统进行种间通讯。观察到的这些 QS 系统在生物膜形成和毒力中的作用以及它们介导跨物种信号传导的能力清楚地表明了了解其作用机制的重要性。这些实验的结果可能为 QS 抑制剂提供新的靶标，以防止生物膜形成并降低与链球菌感染相关的发病率和死亡率。 为了研究 QS 以及 GAS 和 GBS 之间的种间通讯对毒力和生物膜形成的作用，我们将创建不含 RovS 和/或 Shp 肽的 GBS 菌株，并使用荧光素酶报告基因和 qRT-PCR 来测量敲除菌株中的基因表达。我们还将制作基因替换菌株，在 GAS 和 GBS 之间交换 Rgg2 和 RovS，以确定这些蛋白质是否可以相互补充。由于 Shp2/3 已被证明可以增强 GAS 中生物膜的形成，因此将测试每个突变体在生物膜发育中的影响。为了确定肽表达如何与生物膜形成重叠，我们将使用 RNASeq 来确定浮游或生物膜中生长的 GAS 和 GBS 的转录组谱，无论是否存在 Shp 肽。最后，我们将测试这些基因的缺失是否会改变小鼠感染和携带模型中 GAS 和 GBS 的毒力。 总而言之，这些研究将深入了解两种重要的人类病原体在临床相关环境中相互交流的能力。突变研究的数据将使我们能够表征第一个允许不同种类链球菌之间进行交流的信号系统。