The Structural and Functional Determination of Streptococcus mutans Adherence

变形链球菌粘附的结构和功能测定

• 批准号: 10112889
• 负责人: Champion Christdoss Selvakumar Deivanayagam
• 金额: $ 42.24万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10112889
• 关键词: Acids; Address; Adherence; Adhesions; Adopted; Affect; Affinity; Animal Model; Bacterial Adhesins; Binding; Candida albicans; Child; Collagen; Complex; Comprehension; Coupled; Crystallization; Dental Models; Dental caries; Development; Dextrans; Ecology; Ensure; Etiology; Future; Gene Mutation; Genes; Glucans; Glucosyltransferases; Goals; Human; I-antigen; Individual; Investigation; Knowledge; Ligands; Maps; Mediating; Membrane Proteins; Methods; Microbe; Microbial Biofilms; Modeling; Molecular; Mutagenesis; Oral; Oral cavity; Outcome; Outcome Study; Pathogenesis; Pathogenicity; Peptides; Play; Population; Predisposition; Production; Protein C; Proteins; Rattus; Resolution; Rodent Model; Role; Salivary; Scavenger Receptor Cysteine-Rich Domain; Site; Streptococcus Viridans Group; Streptococcus adhesin; Streptococcus gordonii; Streptococcus mutans; Structure; Study models; Surface; Therapeutic; Virulence; combinatorial; comparative; dental biofilm; design; dysbiosis; early childhood; genetic manipulation; glucan-binding protein; glycoprotein 340; microbial; microbial colonization; microorganism; microorganism interaction; mutant; nanomolar; oral streptococci; pathogen; polymicrobial disease; prevent; sortase; tooth surface

Dental caries is a polymicrobial disease that affects much of the human population worldwide, where the harmony of a cooperative eco-organization shifts towards a dysbiotic framework with overrepresentation of pathogenic microorganisms, particularly by Streptococcus mutans (SM). For planktonic SM, adhesion to tooth surface and/or dental biofilms is a crucial step in the pathogenesis of dental caries, and SM has evolved (i) SM- host and (ii) SM-microbial interactions, which are mediated through its surface proteins (adhesins). SM’s adhesion mediated interactions include: (A) The recent discovery of redundant high affinity binding of SM’s adhesins to the scavenger receptor cysteine rich domains (SRCR) of the salivary glycoprotein 340 (Gp340), which promotes caries susceptibility in the SM-host interface; and (B) The revelation of SM’s adhesin required for the SM-Candida albicans (CA) biofilm formation and acid production, which enhances cariogenicity in early childhood caries in the SM-microbial interface. Together these have revealed previously unknown interactions by once thought to be well-known and well-characterized adhesins on SM. Yet the key unanswered question remains, “how does SM mediate such redundant, but specific binding to host proteins and to other microbes?” The goal of this application is to determine the specific motif(s) and/or molecular mechanism(s) that drive SM’s adherence, particularly how they enable binding to multiple ligands. Our structural and functional studies show that SM’s surface adhesins mediate these attachments primarily via two major structural domains, the V- and C-fold. We hypothesize that “the V- and C-fold present on the surface adhesins of SM mediate specific interactions through common binding motif(s) that are crucial for biofilm formation and microbial colonization”. We will address our hypothesis through three specific aims (SAs) by (a) mapping the adherence motif(s) on the V-fold (SA1) and (b) C-fold (SA2) of oral streptococcal adhesins, and (c) investigating the role of SM’s adhesins in the SM-Candida albicans (CA) interface (SA3). The results from this multi-PD/PI study will (i) Determine the binding-motif(s)/mechanisms globally adopted by the V- and C-fold among SM’s adhesins; (ii) Determine the presence of distinct and/or overlapping adherence sites for various ligands; (iii) Provide a comparative analysis of the V- and C-fold of various adhesins from mutans and viridans streptococci, revealing species-specific differences in their binding-motifs/mechanisms; (iv) Characterize the role of SM adhesins at the SM-CA interface; and (v) Elucidate alternations in the microbial ecology modulated by SM’s V- and C-folds, particularly as they relate to dental caries. Our proposed structural analyses, genetic manipulation of key adhesion motif(s) and animal model studies will determine the adherence mechanisms and address the knowledge gap on SM’s V- and C-fold, particularly their crucial role in promoting colonization and virulence. The results will enable future development of selective combinatorial therapeutics to prevent SM’s adherence to host and microbes.

龋齿是一种多种微生物疾病，影响着全世界大部分人口，其中 合作生态组织的和谐转向失调的框架，过度代表 病原微生物，特别是变形链球菌 (SM)。对于浮游SM，对牙齿的粘附 表面和/或牙齿生物膜是龋齿发病机制中的关键步骤，SM 已经进化出 (i) SM- 宿主和 (ii) SM-微生物相互作用，这是通过其表面蛋白（粘附素）介导的。 SM 的粘附介导的相互作用包括： (A) 最近发现冗余的高亲和力结合 SM 对唾液糖蛋白 340 (Gp340) 的清道夫受体富含半胱氨酸结构域 (SRCR) 的粘附素， 促进 SM-宿主界面的龋齿易感性； (B) 需要揭示 SM 的粘附素 用于 SM-白色念珠菌 (CA) 生物膜的形成和酸的产生，从而增强早期的致龋性 SM-微生物界面中的儿童龋齿。这些共同揭示了以前未知的相互作用 曾经被认为是 SM 上众所周知且特征明确的粘附素。然而关键的未解答问题 剩下的问题是，“SM 如何介导这种冗余但与宿主蛋白和其他微生物的特异性结合？” 此应用程序的目标是确定驱动的特定基序和/或分子机制 SM 的粘附性，特别是它们如何能够与多个配体结合。我们的结构和功能研究 表明 SM 的表面粘附素主要通过两个主要结构域介导这些附着，即 V- 和C形折叠。我们假设“SM 表面粘附素上存在的 V 折叠和 C 折叠介导特定的 通过共同的结合基序相互作用，这对于生物膜形成和微生物定植至关重要”。 我们将通过三个具体目标（SA）来解决我们的假设：（a）将坚持主题映射到 口腔链球菌粘附素的 V 折叠 (SA1) 和 (b) C 折叠 (SA2)，以及 (c) 研究 SM 粘附素的作用 在 SM-白色念珠菌 (CA) 界面 (SA3) 中。 这项多 PD/PI 研究的结果将 (i) 确定全球采用的结合基序/机制 通过 SM 粘附素中的 V 型和 C 型折叠； (ii) 确定是否存在不同和/或重叠的依从性 各种配体的位点； (iii) 提供来自 mutans 的各种粘附素的 V 折叠和 C 折叠的比较分析 和草绿色链球菌，揭示其结合基序/机制的物种特异性差异； （四） 表征 SM 粘附素在 SM-CA 界面上的作用； (v) 阐明微生物的变化 SM 的 V 形和 C 形折叠调节的生态，特别是与龋齿相关的生态。 我们提出的结构分析、关键粘附基序的遗传操作和动物模型研究 将确定遵守机制并解决 SM V 型和 C 型方面的知识差距，特别是 它们在促进定殖和毒力方面发挥着至关重要的作用。研究结果将使选择性的未来发展成为可能 防止 SM 粘附宿主和微生物的组合疗法。