Role of the Spx Regulator in Streptococcus mutans

Spx 调节剂在变形链球菌中的作用

• 批准号: 8603236
• 负责人: Jose A Lemos
• 金额: $ 38.24万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-02-05 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8603236
• 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

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，龋齿是困扰人类的最常见传染病之一。变形链球菌的毒性存在于三个核心属性中；它在牙齿表面粘附和形成生物膜的能力，从广泛的碳水化合物中产生大量有机酸的能力，以及耐受环境压力，特别是低ph值的能力。因为耐受性与变形链球菌的毒力交织在一起，解剖使这些细菌在压力条件下在口腔生物膜中茁壮成长的机制是完整理解龋齿发病机制的核心。在革兰氏阳性细菌中，能量依赖性蛋白酶，特别是ClpXP系统，是应激耐受性的核心，并与细菌的发病机制有关。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S. mutans的关键毒力属性表达中起重要作用，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。我们已经证明，spx基因（这里称为spxA和spxB）的失活恢复了在变形链球菌中观察到的许多表型。clpXP菌株。因此，ClpXP影响突变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有关，并且Spx积累与clpP和clpX突变引起的表型密切相关，但Spx在致病菌中的全局调控作用仍有待探索。我们的工作假设是Clp蛋白水解控制Spx调节因子在变形链球菌发病过程中起关键作用。因此，本研究的重点是SpxAB全局调控因子的表征及其在突变链球菌中控制毒力表达的作用。为了证明我们的假设，提出了三个具体目标。在Aim 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额外的见解。在Aim 2中，对？clpXP和？为了揭示spx在潜在发病过程中的调控意义，我们将对spx突变株进行研究。最后，在Aims 3中，全基因组微阵列将用于鉴定Spx控制下的遗传网络，并在与Aims 1和Aims 2结合分析时，鉴定参与毒力表达的新基因。最终，这项提议的进展将有助于鉴定蛋白质和信号通路，这些蛋白质和信号通路可用于开发新的治疗药物来预防龋齿。