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

基本信息

批准号：
8912086
负责人：
BLAISE R BOLES
金额：
$ 22.28万
依托单位：
UNIVERSITY OF IOWA
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-03-01 至 2016-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8912086
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 screening small molecule therapeutic target

项目摘要

DESCRIPTION (provided by applicant): 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 therapeutics. 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.

描述（由申请人提供）：对抗菌药物化疗的耐药性是导致发病率、死亡率和医疗费用上升的主要原因。在过去的几十年里，对传统抗生素产生耐药性的病原体的流行率一直在上升。令人高度关注的是耐甲氧西林金黄色葡萄球菌 (MRSA)，它正在迅速减少金黄色葡萄球菌感染的可用治疗选择。随着耐药性不断出现，迫切需要开发替代治疗方法，例如开发辅助疗法以增强现有抗菌药物的活性。最近我们发现细胞壁修饰酶（称为SsaA1和SsaA2）的酰胺酶活性介导金黄色葡萄球菌生物膜对传统抗生素夫西地酸的抗性。也就是说，ssaA1 或 ssaA2 的基因失活导致生物膜对夫西德敏感酸。这一结果表明，能够抑制SsaA酰胺酶活性的小分子可以作为佐剂与夫西地酸联合使用，以有效消除金黄色葡萄球菌生物膜。 ssaA1 突变体还表现出夫西地酸耐药性出现频率降低，这表明除了使生物膜细菌对抗菌药物敏感之外，小分子 SsaA 酰胺酶抑制剂还会减少耐药细菌的出现。 SsaA 酰胺酶是小分子疗法的理想靶标，因为它们位于细胞外部，易于接近，而且人类缺乏肽聚糖和相关的生物合成机制（包括 SsaA 酰胺酶同源物）。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，并对这些分子进行表征，以用作潜在的辅助治疗药物。为了实现这一目标，我们提出以下目标：(1) 通过高通量筛选鉴定消除 SsaA 酰胺酶活性的化合物；(2) 阐明 SsaA 化学抑制剂在体外和体内使葡萄球菌生物膜对抗菌治疗敏感的能力生物膜发育模型。在下一阶段的研究（R33）中，我们计划通过研究先导化合物的化学优化、表征针对其他革兰氏阳性病原体的抗菌活性以及开发用于体内测试的制剂/递送系统，将我们的基本发现转化为临床应用动物模型。 PI 在金黄色葡萄球菌生物学方面的经验以及密歇根大学化学基因组学中心的实力使我们能够进行这项研究并取得深刻的发现。