Mechanistic Studies on Staphylococcal Quorum Quenching Natural Products

葡萄球菌群体淬灭天然产物的机理研究

• 批准号: 8854031
• 负责人: Cassandra Leah Quave
• 金额: $ 35.48万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8854031
• 关键词: Abscess; Acquired Immunodeficiency Syndrome; Address; Affect; Animals; Anti-Infective Agents; Antibiotic Resistance; Antibiotics; Bacteria; Biological Assay; Biological Availability; Biological Factors; Bypass; Cannabis sativa plant; Cell Line; Cessation of life; Clinical; Column Chromatography; Communicable Diseases; Community Healthcare; Coupled; Crude Extracts; Cyclic Peptides; Data; Development; Disease; Dose; Drug Design; Drug Kinetics; Enzymes; Epithelium; Europe; European; Evaluation; Exhibits; Exposure to; Fagaceae; Food; Fractionation; Fruit; Generations; Genetic; Government; Growth; Half-Life; Hemolysin; High Pressure Liquid Chromatography; Human; Immune system; Infection; Infectious Skin Diseases; Inflammation; Intravenous; Knock-out; Lead; Link; Liquid substance; Lung; Mediating; Medical; Methods; Modeling; Monitor; Mus; Nasal Epithelium; Nature; Output; Pathogenicity; Pathway interactions; Persons; Pharmaceutical Preparations; Phenotype; Plant Leaves; Plants; Process; Production; Property; Proteins; Proteomics; Public Health; RNAIII; Regulator Genes; Reporter; Resistance; Sampling; Scheme; Scientist; Signal Transduction; Skin; Skin Tissue; Soft Tissue Infections; Source; Specimen; Staging; Standardization; Staphylococcus aureus; System; Testing; Therapeutic; Time; Tissues; Topical application; Toxin; Trees; Virulence; Work; base; combat; cytotoxicity; drug discovery; drug metabolism; efficacy evaluation; efficacy testing; forest; improved; in vitro Assay; in vivo; in vivo Model; insight; keratinocyte; methicillin resistant Staphylococcus aureus; microbial; mutant; novel strategies; pathogen; pressure; prevent; quorum sensing; research study; skin abscess; success; voucher

DESCRIPTION (provided by applicant): Staphylococcus aureus is a highly problematic pathogen. Rates of infection in both the community and healthcare setting are on the rise, and coupled with its highly antibiotic-resistant nature, this makes S. aureus a top public health concern. In fact, invasive methicillin-resistant S. aureus (MRSA) is responsible for more deaths in the USA than AIDS. Nevertheless, the number of new antibiotic leads in the pipeline is diminishing, and many scientists have put out a call for the discovery and development of a new class of drugs which could mediate microbial pathogenicity rather than growth and survival. The staphylococcal quorum-sensing pathway, controlled by the accessory gene regulator (agr) system, is a potential target for such anti-pathogenic drug discovery efforts, as it serves as a global regulator of staphylococcal virulence. Following extensive studies on the complementary and alternative medical (CAM) practices of southern Italians in the treatment of skin and soft tissue infection, over 100 plant samples were identified, collected, extracted, and examined for their anti-staphylococcal potential. Among the tests included was a screen for the inhibition of δ-hemolysin, a translational protein product of RNAIII, whose production is regulated through the agr quorum-sensing pathway. Extract 134, which is derived from a popular tree with edible fruits and medicinal leaves and bark, was found to exhibit a strong dose-dependent inhibition of δ-hemolysin at sub-inhibitory concentrations for growth. The dose-dependent quorum-quenching effects of Extract 134 were confirmed through the use of fluorescent genetic reporters for agr (types I-IV). This activity is important based upon previous animal studies with agr knockout mutants that show a diminished capacity to initiate and persist in a skin infection model. In the proposed study, we seek to improve our understanding of the mechanistic basis for Extract 134's quorum-quenching effects and evaluate the therapeutic relevance of such an anti-virulence therapy using in vivo models. The study will address four specific aims: 1) identification and structural elucidation of the active constituent(s) (or marker compounds for standardization) in Extract 134; 2) elucidation of the mechanism of action for the quorum-quenching effects observed; 3) determination of drug metabolism and pharmacokinetic parameters (DM/PK) of the bioactive constituent(s); and 4) evaluation of efficacy in treating S. aureus skin infection in a murine model.

描述（由申请方提供）：金黄色葡萄球菌是一种高度成问题的病原体。社区和医疗机构的感染率都在上升，再加上其高度耐药性，这使得S。金黄色葡萄球菌是最受关注的公共卫生问题。事实上，侵袭性耐甲氧西林S.在美国，金黄色葡萄球菌（MRSA）比艾滋病造成更多的死亡。然而，新抗生素的数量正在减少，许多科学家已经呼吁发现和开发一类新的药物，这些药物可以介导微生物的致病性，而不是生长和存活。葡萄球菌群体感应途径，由辅助基因调节器（agr）系统控制，是一个潜在的目标，这种抗病原体药物的发现工作，因为它作为一个全球性的葡萄球菌毒力调节器。在对意大利南部治疗皮肤和软组织感染的补充和替代医学（CAM）实践进行广泛研究后，对100多个植物样本进行了鉴定、收集、提取和检查，以确定其抗葡萄球菌的潜力。在这些测试中，包括对δ-溶血素的抑制的筛选，δ-溶血素是RNAIII的翻译蛋白产物，其产生通过agr群体感应途径进行调节。发现提取物134（其来自具有可食用果实和药用叶和树皮的流行树）在生长的亚抑制浓度下表现出对δ-溶血素的强烈剂量依赖性抑制。通过使用agr（I-IV型）的荧光遗传报告基因证实了提取物134的剂量依赖性群体淬灭效应。根据之前对agr敲除突变体的动物研究，这种活性很重要，这些突变体在皮肤感染模型中启动和持续的能力减弱。在拟议的研究中，我们试图提高我们对提取物134的群体淬灭作用的机制基础的理解，并使用体内模型评估这种抗毒力疗法的治疗相关性。本研究将解决四个具体目标：1）提取物134中活性成分（或用于标准化的标记化合物）的鉴定和结构阐明; 2）阐明观察到的群体淬灭效应的作用机制; 3）测定生物活性成分的药物代谢和药代动力学参数（DM/PK）;以及4）评价治疗S.金黄色葡萄球菌皮肤感染的小鼠模型。