Eukaryotic-type signaling mediates two-component regulation of GBS virulence

真核型信号传导介导 GBS 毒力的双组分调节

• 批准号: 7805615
• 负责人: Lakshmi Rajagopal
• 金额: $ 38.36万
• 依托单位: SEATTLE CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7805615
• 关键词: Adult; Affinity; Age; Antibiotic Resistance; Appearance; Biochemical; Birth; Complex; Cues; Cytotoxin; Development; Disease; Environment; Enzymes; Evaluation; Exhibits; Family; Foundations; Future; Gene Expression; Gene Expression Regulation; Gene Family; Genes; Genetic Transcription; Goals; Gram-Positive Cocci; Group Identifications; Hemolysin; Human; Incidence; Infection; Knowledge; Link; Measures; Mediating; Microbe; Molecular; Molecular Genetics; Neonatal; Organism; Pathogenesis; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Prevention; Prevention strategy; Prophylactic treatment; Protein-Serine-Threonine Kinases; Proteomics; Regulation; Repression; Research Personnel; Role; Serine; Signal Pathway; Signal Transduction; Site; Streptococcal Infections; Streptococcus; Streptococcus Group B; System; Therapeutic; Threonine; Toxin; Virulence; Virulence Factors; Work; antimicrobial; base; early onset; late disease onset; mutant; neonatal sepsis; neonate; novel; pathogen; premature; prevent; programs; promoter; resistant strain; response; sensor; stillbirth; transcription factor

DESCRIPTION (provided by applicant): Streptococcus agalactiae (Group B streptococci, GBS) are p-hemolytic, gram-positive cocci that cause invasive infections in human neonates and adults. Despite significant advances in prevention and treatment of early onset neonatal disease, rates of GBS-related still births, prematurity, late onset neonatal disease and adult infections are not decreased or prevented. These observations emphasize the importance of alternate strategies for prevention of GBS infections. GBS encounters a wide array of host environments during its disease cycle. Hence, it is essential for the pathogen to rapidly adapt to changing external environments to survive and establish successful infections. Bacterial two component signaling (TCS) systems are critical for pathogens to mediate their adaptive responses to the external/host environment. A TCS composed of a sensor kinase CsrS and a response regulator CsrR regulate expression of GBS cytotoxins i.e. p-hemolysin (P-H/C) and CAMP factor. Our studies have shown that GBS also encodes two eukaryotic-type signaling enzymes comprising a sensor kinase Stk1 and its cognate phosphatase Stp1 that regulate virulence. This proposal seeks to extend our understanding of eukaryotic-type signaling in GBS. Our studies show that the eukaryotic-type kinase Stk1 regulates the expression of GBS cytotoxins (P-H/C and CAMP factor) in a manner that is opposite to the TCS, CsrR/CsrS. Our observation that Stk1 requires CsrR for regulation of cytotoxin expression demonstrates a link between eukaryotic-type and two-component signaling in GBS. The objective of this proposal is to elucidate the interaction between Stk1 and CsrR for adaptive gene expression in GBS. In this proposal, we will also define the role of the cognate signaling components Stp1 and CsrS that regulate Stk1 and CsrR activity, respectively. The three specific aims proposed will 1) define the role of Stp1 on Stk1 regulation of CsrR activity 2) establish the effect of the interaction between Stk1 and CsrR on the ability of CsrS to activate CsrR and 3) determine the functional consequence of Stk1 regulation of CsrR activity. A combination of genetic, molecular, biochemical and proteomic approaches are proposed to elucidate the link between eukaryotic-type and two component signaling mechanisms in GBS. These studies will broaden our understanding on signaling mechanisms employed by GBS to mediate its adaptive responses. This work will provide the foundation for future studies on adaptive gene expression by GBS for survival in various host niches and for evaluation of these signaling components as targets in antimicrobial strategies. Our findings will also have widespread implications on novel mechanisms of signaling that regulate adaptive responses in other pathogenic and non-pathogenic microbes.

描述（由申请人提供）：无乳链球菌（B 族链球菌，GBS）是 p 溶血性革兰氏阳性球菌，可引起人类新生儿和成人的侵袭性感染。尽管在预防和治疗早发性新生儿疾病方面取得了重大进展，但与 GBS 相关的死产率、早产率、晚发性新生儿疾病和成人感染率并未降低或预防。这些观察结果强调了预防 GBS 感染的替代策略的重要性。 GBS 在其疾病周期中会遇到各种各样的宿主环境。因此，病原体必须快速适应不断变化的外部环境才能生存并成功感染。细菌二元信号（TCS）系统对于病原体介导其对外部/宿主环境的适应性反应至关重要。由传感器激酶 CsrS 和反应调节器 CsrR 组成的 TCS 调节 GBS 细胞毒素，即 p-溶血素 (P-H/C) 和 CAMP 因子的表达。我们的研究表明，GBS 还编码两种真核型信号酶，包括传感器激酶 Stk1 及其调节毒力的同源磷酸酶 Stp1。该提案旨在扩展我们对 GBS 真核型信号传导的理解。我们的研究表明，真核型激酶Stk1以与TCS、CsrR/CsrS相反的方式调节GBS细胞毒素（P-H/C和CAMP因子）的表达。我们观察到 Stk1 需要 CsrR 来调节细胞毒素表达，这证明了 GBS 中真核型信号传导和双组分信号传导之间的联系。该提案的目的是阐明 Stk1 和 CsrR 之间的相互作用，以实现 GBS 中适应性基因表达。在本提案中，我们还将定义分别调节 Stk1 和 CsrR 活性的同源信号成分 Stp1 和 CsrS 的作用。提出的三个具体目标将 1) 定义 Stp1 对 Stk1 对 CsrR 活性的调节的作用 2) 确定 Stk1 和 CsrR 之间的相互作用对 CsrS 激活 CsrR 的能力的影响 3) 确定 Stk1 调节 CsrR 的功能结果CsrR 活动。提出结合遗传、分子、生化和蛋白质组学方法来阐明 GBS 真核型和两种成分信号传导机制之间的联系。这些研究将拓宽我们对 GBS 介导其适应性反应的信号机制的理解。这项工作将为未来研究 GBS 在各种宿主环境中生存的适应性基因表达以及评估这些信号成分作为抗菌策略的目标奠定基础。我们的研究结果还将对调节其他致病和非致病微生物适应性反应的新信号机制产生广泛影响。