Role of the Spx Regulator in Streptococcus mutans

Spx 调节剂在变形链球菌中的作用

基本信息

批准号：
8402631
负责人：
Jose A Lemos
金额：
$ 36.71万
依托单位：
UNIVERSITY OF ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-02-05 至 2015-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8402631
关键词：
Acids Affect Bacillus subtilis Bacteria Basic Science Biological Bypass Carbohydrates Cell Survival Cellular Stress Chronic Clinical Research Communicable Diseases Data Dental caries Development Disease Disease Progression Dissection Endocarditis Functional disorder Gene Expression Profile Genes Genetic Genome Genomics Goals Gram-Positive Bacteria Heart Valves Human In Vitro Infection Inflammation Ingestion Lactococcus lactis Life Microbial Biofilms Molecular Mutation Oral cavity Pathogenesis Pathway interactions Peptide Hydrolases Phenotype Physiological Play Process Proteins Proteolysis Qualifying Regulation Regulon Research Role Signal Pathway Streptococcus mutans Stress System Therapeutic Agents Tooth structure Virulence Work base biological adaptation to stress cariogenic bacteria design endopeptidase Clp experience genetic regulatory protein in vivo in vivo Model insight microbial mutant new therapeutic target novel novel therapeutics oral biofilm organic acid pathogen pathogenic bacteria prevent protein complex public health relevance research study stress tolerance sugar tooth surface trait

项目摘要

DESCRIPTION (provided by applicant): Data from clinical and basic research have implicated Streptococcus mutans as the primary microbial etiologic agent of dental caries, one of the most common infectious diseases afflicting humans. The virulence of S. mutans resides in three core attributes; its abilities to adhere and form biofilms on tooth surfaces, to produce large quantities of organic acids from a wide range of carbohydrates, and to tolerate environmental stresses, particularly low pH. Because stress tolerance is intertwined with S. mutans virulence, the dissection of the mechanisms that allow these bacteria to thrive in oral biofilms during stressful conditions is central for a complete understanding of the pathogenesis of dental caries. In Gram-positive bacteria, energy-dependent proteases, in particular the ClpXP system, are central for stress tolerance and have been implicated in bacterial pathogenesis. However, a clear picture of the biological role of Clp proteases in pathogenesis has yet to emerge. Our recent work revealed that ClpXP plays an important role in the expression of key virulence attributes of S. mutans, including biofilm formation, cell viability and acid tolerance. In Bacillus subtilis, the global regulator Spx is a substrate of ClpXP, and accumulation of Spx has been correlated to phenotypes of ?clpXP strains. We have demonstrated that inactivation of spx genes (herein designated spxA and spxB) restored many phenotypes observed in the S. mutans ?clpXP strains. Thus, the underlying mechanisms by which ClpXP affects virulence traits in S. mutans are intimately associated with accumulation of Spx. Despite the linkage of Clp proteolysis with bacterial virulence, and the close association of Spx accumulation with phenotypes resulting from clpP and clpX mutations, the effects of global regulation by Spx in pathogenic bacteria remains to be explored. Our working hypothesis is that Clp proteolytic control of the Spx regulator plays a critical role in processes underlying S. mutans pathogenesis. Therefore, this application focuses on the characterization of the SpxAB global regulators, and their role in controlling virulence expression in S. mutans. To prove our hypothesis, three Specific Aims are proposed. In Aim 1, we will dissect the transcriptional and post-translational mechanisms regulating Spx levels, which will provide additional insights into the molecular and physiologic significance of the interactions between Clp proteases and Spx. In Aim 2, a thorough in vitro and in vivo characterization of the ?clpXP and ?spx mutant strains will be conducted in order to disclose the significance of Spx regulation in processes underlying pathogenesis. Finally, in Aim 3 whole genomic microarrays will be used to identify the genetic network under Spx control and, when analyzed in conjunction with Aims 1 and 2, to identify new genes that participate in the expression of virulence. Ultimately, the advances from this proposal will help the identification of proteins and signaling pathways that could be used for the development of novel therapeutic agents to prevent dental caries.

描述（由申请人提供）：来自临床和基础研究的数据表明变形链球菌是龋齿的主要微生物病原体，龋齿是困扰人类的最常见传染病之一。变形链球菌的毒力体现在三个核心属性上：它能够在牙齿表面粘附并形成生物膜，从多种碳水化合物中产生大量有机酸，并能够耐受环境压力，特别是低 pH 值。由于应激耐受性与变形链球菌毒力交织在一起，因此剖析这些细菌在应激条件下在口腔生物膜中繁殖的机制对于全面了解龋齿的发病机制至关重要。在革兰氏阳性细菌中，能量依赖性蛋白酶，特别是 ClpXP 系统，是应激耐受的核心，并且与细菌发病机制有关。然而，Clp 蛋白酶在发病机制中的生物学作用尚不清楚。我们最近的工作表明，ClpXP 在变形链球菌关键毒力属性的表达中发挥着重要作用，包括生物膜形成、细胞活力和耐酸性。在枯草芽孢杆菌中，全局调节因子 Spx 是 ClpXP 的底物，Spx 的积累与 ?clpXP 菌株的表型相关。我们已经证明，spx 基因（本文指定为 spxA 和 spxB）的失活恢复了在变形链球菌 ?clpXP 菌株中观察到的许多表型。因此，ClpXP 影响变形链球菌毒力性状的潜在机制与 Spx 的积累密切相关。尽管 Clp 蛋白水解与细菌毒力存在联系，并且 Spx 积累与 clpP 和 clpX 突变引起的表型密切相关，但 Spx 在病原菌中的整体调节作用仍有待探索。我们的工作假设是 Clp 对 Spx 调节器的蛋白水解控制在变形链球菌发病机制的过程中发挥着关键作用。因此，本申请重点关注 SpxAB 全局调节因子的表征及其在控制变形链球菌毒力表达中的作用。为了证明我们的假设，提出了三个具体目标。在目标 1 中，我们将剖析调节 Spx 水平的转录和翻译后机制，这将为 Clp 蛋白酶和 Spx 之间相互作用的分子和生理意义提供更多见解。在目标 2 中，将对 ?clpXP 和 ?spx 突变株进行彻底的体外和体内表征，以揭示 Spx 调节在潜在发病机制中的重要性。最后，在目标 3 中，全基因组微阵列将用于识别 Spx 控制下的遗传网络，并在与目标 1 和 2 结合分析时，识别参与毒力表达的新基因。最终，该提案的进展将有助于鉴定蛋白质和信号通路，可用于开发预防龋齿的新型治疗剂。