Targeting Clostridioides difficile with microbiome-sparing, resistant-proof anti-toxins

使用保留微生物组、抗耐药性的抗毒素来靶向艰难梭菌

• 批准号: 10115406
• 负责人: Vern L. Schramm
• 金额: $ 66.87万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10115406
• 关键词: Affect; Affinity; Animals; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Apoptosis; Bacterial Toxins; Binding; Biological Assay; Catalytic Domain; Ceftriaxone; Cells; Centers for Disease Control and Prevention (U.S.); Cessation of life; Chemicals; Clinical; Clinical Trials; Clostridium difficile; Colitis; Complex; Crystallization; Crystallography; Cytoskeleton; Development; Disease; Drug Design; Drug resistance; Electrostatics; Environment; Epithelial Cells; Equilibrium; Evolution; FDA approved; Fatal Outcome; GTP-Binding Proteins; Glucose; Glucosyltransferase; Glucosyltransferases; Guidelines; Health Care Costs; Hospitals; Human; Hydrolysis; Hypotension; Ileus; Immunity; Infection; Infection prevention; Isotopes; Kinetics; Knowledge; Lactamase; Lead; Life; Maps; Medical; Megacolon; Methods; Microfilaments; Modeling; Molecular; Monoclonal Antibody Therapy; Morbidity - disease rate; North America; Oral; Organism; Pathology; Pathway interactions; Patients; Pattern; Pharmaceutical Preparations; Population; Process; Production; Proliferating; Proteins; Pseudomembranous Colitis; Reaction; Recovery; Reporting; Reproduction spores; Resistance; Roentgen Rays; Shock; Structure; Technology; Testing; Thermodynamics; Threonine; Tissues; Toxic effect; Toxin; Transferase; United States National Institutes of Health; Uridine Diphosphate Sugars; Vaccines; Vancomycin; Virulence Factors; World Health Organization; analog; antitoxin; base; cdc42 GTP-Binding Protein; computational chemistry; cytotoxicity; design; fecal transplantation; gastrointestinal epithelium; glycosylation; glycosyltransferase; gut microbiome; gut microbiota; healthcare-associated infections; holotoxins; inhibitor/antagonist; innovation; insight; microbial; microbiome; mortality; mouse model; neutralizing antibody; novel; oral infection; pathogen; pathogenic bacteria; phase II trial; preservation; pressure; prevent; programs; quantum chemistry; recurrent infection; rho; screening; small molecule; symptom treatment

Abstract: Human gut infections by Clostridioides (Clostridium) difficile (here, C.diff.) are the most lethal urgent threat in the 2019 CDC Antibiotic Resistance Threats Report. Excess healthcare costs from these infections have been estimated to be over $5 billion annually. Antibiotic resistance has elicited an insightful RFA RA18-725, `Generating new insights and mechanistic understanding of antibiotic resistance'. C.diff. infections (CDI) typically arise following treatment of other clinical disorders with antibiotics. Antibiotic therapy disrupts normal gut microbiota, allowing C.diff. to proliferate and to repopulate the gut following treatment. Additional antibiotic therapy to treat CDI prevents return of normal gut microbiota, leading to recurrent infections in over 20% of patients. C.diff. has acquired resistance to several common antibiotics, compounding its therapy. Recent clinical guidelines (2018) for C.diff. infections are oral vancomycin for patients in shock, hypotension, ileus or megacolon. Fecal transplant is recommended for nonresponsive infections following vancomycin treatment. mAb therapies have been FDA- approved, but are not recommended. Despite these therapies, C. difficile causes an estimated 224,000 infections and 13,000 deaths per year (CDC in 2017). Gut epithelial cell cytotoxicity results from C.diff. production of secreted toxins, primarily TcdA and TcdB (Tcds). Tcds are processed in gut cells to form active UDP-glucosyl transferases that glucosylate cytoskeletal-regulating Rho, Rac and Cdc42 GTP-binding proteins on specific threonines. Loss of cytoskeletal integrity causes severe colitis and can have a fatal outcome. Anti-toxin immunity is a historic approach to prevent host damage from circulating bacterial toxins. We propose that small molecule, tight-binding inhibitors targeting C.diff. Tcds can prevent the morbidity and mortality from gut toxins in C.diff. infections. Our transition state analog approach uses kinetic isotope effects and quantum chemistry to solve transition state structures of Tcds. Solving the first transition state structures of G-protein glucosyltransferases, and developing the first transition state analog of any UDP-sugar transferase is innovative. Electrostatic potential models of Tcd transition states will guide the design and synthesis of transition state analogs. Lead transition state analog candidates will be elaborated by cycles of crystallography and chemical design. Candidate compounds and crystal structures of Tcd complexes have been obtained in preliminary studies. Inhibitors will be characterized against Tcds in human cells and in mouse models. Agents to prevent tissue damage from C.diff. infections, without disruption of the gut microbiome or pressure for microbial resistance have important medical relevance. Inhibition of Tcds in gut epithelial cells places no selective pressure for antibiotic or anti-toxin resistance on C.diff. or on the gut microbiome, while protecting the gut by neutralizing Tcds. Mechanistically, this approach is innovative in recapitulating vaccine-based antibody neutralization of toxins using the powerful approach of transition state analogs.

摘要：梭状芽孢杆菌（梭状芽胞杆菌）艰难梭菌（这里，C.Diff。）是人类的肠道感染是最紧急的致命的 2019年CDC抗生素耐药性威胁报告中的威胁。这些感染中的过多医疗保健费用有 估计每年超过50亿美元。抗生素耐药性引起了有见识的RFA RA18-725， “产生新的见解和对抗生素耐药性的机械理解”。 C.Diff。通常感染（CDI） 在治疗其他抗生素疾病后会出现。抗生素疗法破坏正常肠道 微生物群，允许C.Diff。在处理后增殖并重新填充肠道。其他抗生素疗法 为了治疗CDI可防止正常肠道菌群的返回，导致超过20％的患者反复感染。 C.Diff。 已经获得了对几种常见抗生素的耐药性，使其疗法更加复杂。最近的临床准则（2018） 用于C.Diff。感染是震动，低血压，肠或巨麦龙的患者的口服万古霉素。粪便移植 建议在万古霉素治疗后用于无反应性感染。 mAb疗法已是FDA- 已批准，但不建议进行。尽管有这些疗法，艰难梭菌仍会引起大约224,000次感染 每年13,000人死亡（2017年的CDC）。肠道上皮细胞细胞毒性来自C.Diff。生产 分泌的毒素，主要是TCDA和TCDB（TCD）。 TCD在肠道细胞中进行处理以形成活跃的UDP-葡萄糖基 在特定上的转移葡萄糖酸酯细胞骨架调节的RHO，RAC和CDC42 GTP结合蛋白 胸骨。细胞骨架完整性的丧失会导致严重的结肠炎，并可能产生致命的结果。 抗毒素免疫是一种历史方法，可防止循环细菌毒素损害宿主。我们 提出针对C.Diff的小分子，紧密结合的抑制剂。 TCD可以防止发病率和死亡率 来自C.Diff的肠毒素。感染。我们的过渡状态模拟方法使用动力学同位素效应和量子 化学以解决TCD的过渡状态结构。解决G蛋白的第一个过渡状态结构 葡萄糖基转移酶，以及任何UDP糖转移酶的第一个过渡态类似物都是创新的。 TCD过渡状态的静电电势模型将指导过渡状态的设计和合成 类似物。铅过渡状态模拟候选者将通过晶体学和化学的循环详细说明 设计。在初步研究中已经获得了TCD复合物的候选化合物和晶体结构。 抑制剂将在人类细胞和小鼠模型中针对TCD的特征。 防止C.Diff组织损害组织损害的代理。感染，而不会破坏肠道微生物组或 微生物抗性的压力具有重要的医学相关性。在肠道上皮细胞中抑制TCD C.Diff没有选择性的抗生素或抗毒素耐药性的压力。或在肠道微生物组上，同时保护 肠道中和TCD。从机械上讲，这种方法在概括性疫苗抗体方面具有创新性 使用强大的过渡状态类似物对毒素进行中和。