DETERMINATION OF THE ROLE OF Smu.833 IN THE FITNESS AND VIRULENCE OF CARIOGENIC STREPTOCOCCUS MUTANS

测定 Smu.833 在致龋性变形链球菌的适应性和毒力中的作用

• 批准号: 9171316
• 负责人: Katherine L. Rainey
• 金额: $ 4.44万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9171316
• 关键词: Adherence; Alabama; Bacteria; Bacterial Adhesins; Binding; Binding Proteins; Biological Assay; Caries prevention; Cell Fraction; Child; Collaborations; Collagen; Communicable Diseases; Complement; Complex; Data; Dental Enamel; Dental caries; Diet; Dietary Sucrose; Dietary Sugars; Disease; Eating; Elderly; Environment; Enzymes; Gel; Genes; Genetic; Glucans; Glucose; Glucosyltransferases; Goals; Health; Homologous Gene; Hydrogen Peroxide; Impairment; In Vitro; Infective endocarditis; Intake; Lactic acid; Length; Mass Spectrum Analysis; Metabolism; Microbial Biofilms; Modeling; Modification; Nutritional; Oral cavity; Oxidative Stress; Pain; Parents; Pathway interactions; Phenotype; Play; Population; Prevalence; Production; Proteins; Proteomics; Rattus; Regulation; Research; Role; Science; Serotyping; Streptococcus mutans; Surface; Testing; Therapeutic Uses; Universities; Virulence; Virulence Factors; bacterial fitness; commensal microbes; demineralization; effective therapy; extracellular; fitness; genetic regulatory protein; genome-wide; glucosyltransferase B; glycosylation; glycosyltransferase; in vivo Model; interest; killings; mutant; new therapeutic target; oral commensal; oral pathogen; pathogenic bacteria; polymerization; protein profiling; protein protein interaction; targeted treatment; therapeutic target; tooth surface

 DESCRIPTION (provided by applicant): Dental caries, more commonly known as tooth decay, is the most common infectious disease worldwide and is increasing in prevalence among young children despite advancements in caries research. Untreated cavities can cause severe pain and impairment of eating, leading to reduced nutritional intake and diet-related ill health especially for children and the elderly. The main etiological agent of dental caries is Streptococcus mutans which can readily form a biofilm on the surface of teeth and produce lactic acid through the metabolism of dietary sugars which is largely responsible for the demineralization and subsequent destruction of tooth enamel. In addition, S. mutans synthesizes extracellular glucosyltransferases (Gtfs) capable of breaking apart dietary sucrose and polymerizing the glucose subunits into the sticky glucan matrix of the biofilm, imperative for the formation of robust, three-dimensional biofilms. Currently used caries therapies are not species-specific and kill pathogenic species as well as commensal species which are protective against the formation of pathogenic biofilms. There are a number of proteins in S. mutans whose function remains unknown but which could present new targets for S. mutans specific anti-caries treatment. One such protein is a conserved, putative glycosyltransferase encoded by the gene smu.833 in S. mutans strain UA159. A homologue of Smu.833 in a different serotype of S. mutans, has been shown to glycosylate an important surface collagen binding protein important for bacterial colonization in infective endocarditis. Thus, this protein makes a good candidate to be studied and analyzed for its potential as a target for caries therapies. In order o characterize this protein in S. mutans, we created a deletion mutant and assayed for phenotypic changes in bacterial fitness and virulence. Initial studies revealed decreased levels of Gtfs and subsequent glucan matrix formation within the mutant, as well as additional intriguing phenotypes including increased bacterial chain length and aggregation, increased sensitivity to oxidative stress, and increased levels of biofilm regulatory protein. The results obtained thus far have led to the hypothesis that Smu.833 is required both for Gtf glycosylation and stability and for an additional role in S. mutans which more globally effects bacterial fitness and virulence. To test this hypothesis, we propose three specific aims: Aim 1: Determine the role of Smu.833 in Gtf expression; Aim 2: Determine the global role Smu.833 plays in bacterial fitness and virulence ; Aim 3: Determine the effect of Smu.833 on bacterial competitiveness. Elucidating the role of Smu.833 in S. mutans will help unravel the complex interactions that govern the fitness and virulence of this bacterium. Furthermore, results from this application may present a new species-specific target for therapeutics used in the prevention of dental caries, a costly and painful disease which effects the vast majority of the world's population.

 描述（由申请人提供）：龋齿，通常称为蛀牙，是世界范围内最常见的传染病，尽管龋齿研究取得了进展，但未经治疗的蛀牙会导致严重疼痛和进食障碍，导致幼儿中的患病率不断增加。减少营养摄入和饮食相关的不良健康，尤其是儿童和老年人。 龋齿的主要病原体是变形链球菌，它很容易在牙齿表面形成生物膜，并通过代谢产生乳酸。膳食糖主要导致牙釉质脱矿和随后的破坏。此外，变形链球菌合成细胞外葡萄糖基转移酶 (Gtfs)，能够分解膳食蔗糖并将葡萄糖亚基聚合到生物膜的粘性葡聚糖基质中。目前使用的龋齿治疗方法不是物种特异性的，可以杀死致病物种以及防止形成的共生物种。变形链球菌中有许多蛋白质的功能尚不清楚，但它们可能为变形链球菌特异性抗龋齿治疗提供新的靶标，其中一种蛋白质是由基因 smu.833 编码的保守的假定糖基转移酶。在变形链球菌菌株 UA159 中，不同血清型变形链球菌中的 Smu.833 的同源物已被证明能够使重要的表面胶原结合蛋白糖基化。因此，该蛋白是研究和分析其作为龋齿治疗靶标的潜力的良好候选者，为了表征变形链球菌中的该蛋白，我们创建了一个缺失突变体并进行了分析。初步研究揭示了细菌适应性和毒力的表型变化，以及突变体中 Gtfs 水平的降低和随后的葡聚糖基质形成，以及其他有趣的表型，包括细菌链长度和聚集的增加、对细菌的敏感性增加。氧化应激和生物膜调节蛋白水平增加迄今为止获得的结果。 导致这样的假设：Smu.833 对于 Gtf 糖基化和稳定性以及在变形链球菌中的额外作用都是必需的，从而更全面地影响细菌的适应性和毒力。 检验这一假设，我们提出三个具体目标： 目标 1：确定 Smu.833 在 Gtf 表达中的作用；目标 2：确定 Smu.833 在细菌适应性和毒力中的总体作用；目标 3：确定 Smu 的作用。第833章 阐明Smu.833在变形链球菌中的作用将有助于揭示控制适应性和毒力的复杂相互作用。此外，该应用的结果可能为预防龋齿提供新的物种特异性治疗靶标，龋齿是一种影响世界绝大多数人口的昂贵而痛苦的疾病。