Host range determinants of bacterial exfoliative toxins

细菌剥脱性毒素的宿主范围决定因素

• 批准号: 10742306
• 负责人: Matthew Frederick Barber
• 金额: $ 22.13万
• 依托单位: UNIVERSITY OF OREGON
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-16 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10742306
• 关键词: Address; Amino Acids; Animals; Bacteria; Bacterial Infections; Binding; Biochemical; Biological Assay; Bulla; Cadherins; Cell Adhesion; Cells; Chromosome Mapping; Collection; Complex; Crystallography; Desmosomes; Development; Disease; Disease Outbreaks; Endocarditis; Epidermis; Evolution; Exfoliatins; Exfoliative Toxins; Future; Genes; Genetic; Genetic Drift; Genetic Variation; Genus staphylococcus; Goals; Human; Impetigo; Infection; Infectious Skin Diseases; Integration Host Factors; Intercellular Junctions; Investigation; Knowledge; Life; Maps; Measures; Mediating; Membrane Proteins; Modeling; Molecular; Mutagenesis; Mutation; Natural Selections; Osteomyelitis; Pathogenesis; Pathogenicity; Peptide Hydrolases; Pneumonia; Positioning Attribute; Predisposition; Primates; Production; Proteins; Recombinants; Resolution; Risk Assessment; Sepsis; Site; Skin; Skin Tissue; Soft Tissue Infections; Specificity; Staphylococcal Scalded Skin Syndrome; Staphylococcus aureus; Surface; System; Testing; Toxin; Tropism; Variant; Virulence; Virulence Factors; Work; Zoonoses; combinatorial; design; desmoglein; desmoglein 1; human disease; human pathogen; improved; in vitro Assay; mutant; nonhuman primate; novel therapeutics; pathogen; pathogenic bacteria; pathogenic microbe; prevent; skin barrier; skin disorder; spillover event

PROJECT SUMMARY The host range, or tropism, of pathogen virulence factors is a key determinant of infection. A detailed understanding of host and pathogen mutations that control species tropism is required in order to assess the risk of future zoonotic disease outbreaks, improve animal infection models, and design new therapeutics that take advantage of host specificity. The objective of this proposal is to define barriers to cross-species activity in bacterial virulence factors at high resolution, leveraging staphylococcal exfoliative toxins as a study system. Exfoliative toxins encoded by pathogenic bacteria in the genus Staphylococcus cause life- threatening skin diseases including staphylococcal scalded skin syndrome and bullous impetigo characterized by widespread blistering and damage to the epidermis. Exfoliative toxins are proteases that act by selectively cleaving the skin desmosomal cadherin desmoglein-1, leading to loss of epidermal barrier function and blister formation. Our central hypothesis is that virulence factor activity is dependent on genetic compatibilities between hosts and pathogens, and that interrogating these compatibilities will uncover specific barriers to host tropism. In preliminary work, we found that genes encoding desmoglein-1 have undergone rapid evolution and repeated natural selection across non-human primates within a small protein surface sufficient to restrict toxin activity. We have also developed tractable in vitro assays to measure toxin cleavage of recombinant desmglein-1 from various host species. The Specific Aims of this proposal are to 1) generate a high-resolution map of mutations in desmoglein-1 that restrict toxin tropism, and 2) test how toxin mutations at the desmoglein-1 binding interface contribute to host tropism. In Aim 1 we will perform combinatorial mutagenesis of the toxin recognition surface in desmoglein-1 to produce a genetic map defining the barriers of host recognition. In Aim 2 we will apply structural and biochemical approaches to resolve the desmoglein- exfoliative toxin binding interface combined with genetics to assess how toxin mutations at this surface control host tropism. Collectively this proposal will establish a framework to define genetic barriers to bacterial infections at high-resolution, applied towards the goal of anticipating and preventing future disease outbreaks.

项目摘要 病原体毒力因子的宿主范围或端主是感染的关键决定因素。一个 对控制物种朝向主义的宿主和病原体突变的详细理解是需要 为了评估未来人畜共患疾病爆发的风险，改善动物感染模型和 设计利用宿主特异性的新治疗剂。 该提议的目的是定义细菌中跨物种活动的障碍 高分辨率的毒力因子，利用葡萄球菌去角质毒素作为研究系统。 在葡萄球菌中由致病细菌编码的剥落性毒素会导致生命 威胁皮肤疾病，包括葡萄球菌烧结的皮肤综合征和大胆的脓疱病 具有广泛的表皮和损害的特征。去角质毒素是 通过选择性切割皮肤脱染色体钙粘蛋白脱木蛋白1来起作用的蛋白酶，导致 表皮屏障功能的丧失和水泡形成。我们的中心假设是毒力 因子活性取决于宿主和病原体之间的遗传兼容性，并且 询问这些兼容性将发现宿主往往的特定障碍。在初步工作中， 我们发现编码Desmoglein-1的基因已经经历了快速进化并重复自然 在足以限制毒素活性的小蛋白质表面内的非人类灵长类动物的选择。 我们还开发了可拖动的体外测定方法，以测量重组的毒素裂解 来自各种宿主物种的Desmglein-1。 该提议的具体目的是1）在 desmoglein-1限制毒素的向毒素，以及2）测试desmoglein-1结合的毒素突变 界面有助于宿主向潮流。在AIM 1中，我们将执行毒素的组合诱变 Desmoglein-1中的识别表面以产生定义宿主障碍的遗传图 认出。在AIM 2中，我们将采用结构和生化方法来解决Demoglein- 去角质性毒素结合界面与遗传学结合，以评估毒素突变如何在这种情况下 表面控制宿主的向流。该提议总共建立一个框架来定义遗传 高分辨率的细菌感染的障碍，用于预期和 防止未来的疾病暴发。