Development of adjunctive therapies directed at S. aureus amidases

针对金黄色葡萄球菌酰胺酶的辅助疗法的开发

• 批准号: 8702797
• 负责人: BLAISE R BOLES
• 金额: $ 0.38万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-03-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8702797
• 关键词: Address; Amidohydrolases; Animal Model; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Antimicrobial Resistance; Bacteria; Bacterial Infections; Biochemical; Biological Assay; Biology; Blood; Cell Wall; Cells; Chemicals; Cleaved cell; Communicable Diseases; Communities; Data; Development; Drug Formulations; Drug resistance; Endocarditis; Enzymes; Fluorescence Resonance Energy Transfer; Foundations; Frequencies; Funding; Fusidic Acid; Future; Generations; Genetic; Genomics; Genus staphylococcus; Goals; Gram-Positive Bacteria; Growth; Health; Health Care Costs; Human; Implant; In Vitro; Infection; Lead; Libraries; Life; Mediating; Medical Device; Michigan; Microbial Biofilms; Mission; Modeling; Morbidity - disease rate; Names; Organism; Osteomyelitis; Peptides; Peptidoglycan; Phase; Positioning Attribute; Prevalence; Research; Resistance; Resources; Staphylococcus aureus; Structure-Activity Relationship; Surface; Swimming; System; Testing; Therapeutic; Therapeutic Studies; Time; Tissues; Toxic effect; Translating; United States National Institutes of Health; Universities; Validation; Work; amidase; antimicrobial; chemotherapy; clinical application; crosslink; design; drug resistant bacteria; enzyme activity; experience; high throughput screening; improved; in vivo; in vivo Model; inhibitor/antagonist; member; methicillin resistant Staphylococcus aureus; mortality; mutant; novel; novel strategies; novel therapeutics; pathogen; prevent; public health relevance; screening; small molecule; therapeutic target

Project Summary/Abstract Resistance to antimicrobial chemotherapies is a major contributor to morbidity, mortality, and rising healthcare costs. The prevalence of drug-resistant pathogens against conventional antibiotics has been rising over the last several decades. Of great concern is methicillin-resistant Staphylococcus aureus (MRSA), which is rapidly diminishing the available treatment options for S. aureus infections. As drug resistances continue to emerge there is an urgent need to develop alternative therapeutic approaches such as the development of adjunctive therapies to potentiate the activity of existing antimicrobials. Recently we have discovered that amidase activity of cell wall modifying enzymes (named SsaA1 and SsaA2) mediates S. aureus biofilm resistance to the conventional antibiotic fusidic acid. That is, genetic inactivation of ssaA1 or ssaA2 results in sensitivity of biofilms to fusidic acid. This result suggests that small molecules capable of inhibiting SsaA amidase activity could be used as an adjunctive in conjunction with fusidic acid to effectively eliminate S. aureus biofilms. Mutants in ssaA1 also displayed reduced frequency of fusidic acid resistance emergence, suggesting that in addition to rendering biofilm bacteria sensitive to an antimicrobial, small molecule SsaA amidase inhibitors would also reduce the emergence of drug resistant bacteria. SsaA amidases are an ideal target for small molecule therapies because they are located on the outside of cells making them readily accessible and because humans lack peptidoglycan and the associated biosynthetic machinery (including SsaA amidase homologous). The primary goal of this R21 research is to identify chemical inhibitors of SsaA amidase activity and characterize these molecules for use as potential adjunctive theraputics. To achieve the goal, we propose the following aims: (1) Identify chemical compounds that eliminate SsaA amidase activity via high throughput screening and (2) Elucidate the ability of SsaA chemical inhibitors to sensitize Staphylococcus biofilms to antimicrobial treatment in in vitro and in vivo models of biofilm development. During the next phase of research (R33), we plan on translating our basic findings for clinical applications by investigating chemical optimization of lead compounds, characterizing antimicrobial activity against other gram-positive pathogens, and developing formulation/delivery systems to be tested with in vivo animal models. The PI's experience in S. aureus biology and the strength of the University of Michigan's Center for Chemical Genomics uniquely position us to conduct this research and make profound discoveries.

项目总结/摘要 抗菌药物化疗耐药性是导致发病率、死亡率和医疗保健费用上升的主要因素 成本近年来，对传统抗生素具有耐药性的病原体的流行率一直在上升。 过去几十年。耐甲氧西林金黄色葡萄球菌（MRSA）引起了极大的关注， 减少了S的可用治疗选择。金黄色葡萄球菌感染随着抗药性的不断出现 迫切需要开发替代的治疗方法， 增强现有抗菌剂活性的治疗方法。最近我们发现酰胺酶活性 细胞壁修饰酶SsaA 1和SsaA 2介导S.金黄色葡萄球菌生物膜对 常规抗生素夫西地酸。也就是说，ssaA 1或ssaA 2的遗传失活导致对 生物膜转化为夫西地酸。该结果表明，能够抑制SsaA酰胺酶活性的小分子 可与夫西地酸配合使用，有效地清除S。金黄色葡萄球菌生物膜 ssaA 1的突变体也显示出夫西地酸抗性出现频率降低，这表明在 除了使生物膜细菌对抗菌剂敏感之外，小分子SsaA酰胺酶抑制剂 也会减少抗药性细菌的出现。SsaA酰胺酶是一种理想的靶点， 分子疗法，因为它们位于细胞的外部，使它们容易接近， 因为人类缺乏肽聚糖和相关的生物合成机制（包括SsaA酰胺酶 同源）。这项R21研究的主要目标是鉴定SsaA酰胺酶活性的化学抑制剂 并表征这些分子作为潜在的连续治疗剂的用途。为了实现这一目标，我们建议 本研究的主要目的是：（1）通过高通量的方法鉴定能够消除SsaA酰胺酶活性的化合物 筛选和（2）阐明SsaA化学抑制剂对葡萄球菌生物膜致敏的能力， 在生物膜发展的体外和体内模型中的抗微生物处理。在下一阶段的研究中 (R33)我们计划通过研究化学优化将我们的基本发现转化为临床应用 铅化合物，表征对其他革兰氏阳性病原体的抗菌活性， 在某些实施方案中，将使用体内动物模型测试制剂/递送系统。PI在S.金黄色葡萄球菌 和密歇根大学化学基因组学中心的力量使我们能够进行 这一研究，并作出深刻的发现。