The role of GraRS in resistance to cationic antimicrobial peptides in S. aureus

GraRS 在金黄色葡萄球菌对阳离子抗菌肽耐药中的作用

• 批准号: 8023804
• 负责人: Ambrose Lin Yau Cheung
• 金额: $ 49.95万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-12-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8023804
• 关键词: ATP phosphohydrolase; ATP-Binding Cassette Transporters; Alanine; Anatomy; Animals; Antibiotic Resistance; Antibiotics; Antimicrobial Cationic Peptides; Area; Bacteremia; Bacteria; Binding; Blood Circulation; Blood Platelets; Body Fluids; Charge; Communities; Community Hospitals; Complement; Cyclic Peptides; Daptomycin; Development; Endocarditis; Event; Exposure to; Focal Infection; Future; Genes; Genetic; Genome; Goals; HMGN Proteins; Host Defense; Human; Indium; Individual; Infection; Infectious Skin Diseases; Infective endocarditis; Integration Host Factors; Length; Life; Link; Lysine; Mediating; Membrane; Membrane Biology; Microarray Analysis; Modeling; Molecular; Molecular Genetics; Mutation; Natural Immunity; Operon; Organism; Oryctolagus cuniculus; Outcome; Oxacillin; Pathogenesis; Patients; Peptides; Phospholipids; Phosphotransferases; Play; Polymyxin Resistance; Predisposition; Proteins; Research; Resistance; Resistance development; Risk; Role; Source; Staphylococcus aureus; Stimulus; Structure; Structure-Activity Relationship; Surface; System; Teichoic Acids; Tissues; Vancomycin; Vancomycin-resistant S. aureus; Virulence; Virulent; antimicrobial; antimicrobial peptide; base; design; epimerase; extracellular; in vivo; indolicidin; interest; killings; methicillin resistant Staphylococcus aureus; neutrophil; pathogen; peptide structure; permease; resistance mechanism; response; sensor; skills; sugar

DESCRIPTION (provided by applicant): S. aureus is a highly adaptive human pathogen. One result of this adaptation is its ability to develop resistance cationic antimicrobial peptides (CAPs), which are an important part of innate immunity in the hosts. In perusing the S. aureus genomes, we found four two component regulatory systems each of lie adjacent to an ABC transporter system. One of the system, GraRS, regulates the adjacent VraFG efflux system comprising an ATPase and a membrane permease. Mutations in graR or vraG have led to a reduction in resistance to CAPs such as RP-1 (a congener to PMP-1 from platelets) and hNP-1 (from neutrophils), indolicidin and LL37. As an intravascular pathogen, S. aureus likely encounters CAPs from platelets and neutrophils (RP-1 and hNP-1), which we will focus on in this proposal. The exposure of S. aureus to selective CAP has also led to induction of graRS and vraFG and other genes relevant CAP resistance including mprF, dltABCD and also another set of ABC transporter genes vraDE, based on induction studies and microarray analysis. However, the exact contribution of these genes to CAP resistance mediated by GraRS in S. aureus is not defined (Aim I). In addition, in contrast to S. epidermidis where the expression of graRS and vraFG can be induced by any CAPs, the induction in S. aureus is more selective, responding to only a few CAPs. Based on the difference in the sequence of the kinase sensor GraS between S. aureus and S. epidermidis, we propose to define the exact residues within GraS that mediate this recognition of specific CAPs for induction of downstream genes (Aim II). Besides the bacterial factors, we are also interested in the structure of synthetic CAPs and their ability to bind and induce expression of graRS (Aim III). Finally, the in vivo correlate of these finding in GraRS will be explored in a relevant rabbit model of infective endocarditis. Together, these studies will elicit the scientific basis of innate resistance to relevant host CAPs in S. aureus, thus providing a platform to devise strategies to alleviate resistance to cationic antimicrobial peptides. PUBLIC HEALTH RELEVANCE: Innate resistance to cationic antimicrobial peptides in Staphylococcus aureus is part of the armamentarium of this virulent pathogen. This resistance has developed from genes integral to the S. aureus genome and not from externally acquired genes. We have found that genes encoding a two-component regulatory system and the adjacent transporter genes are important for this resistance. We propose to define the mechanism of this resistance. Our long-term goal is to characterize these genes that confer sensitivity to cationic antimicrobial peptides so that we can design better peptide-based antibiotics in the future.

描述（由申请人提供）：金黄色葡萄球菌是一种高度适应性的人类病原体。这种适应的结果是它具有开发抗性阳离子抗菌肽（CAP）的能力，这是宿主先天免疫的重要组成部分。在仔细阅读金黄色葡萄球菌基因组时，我们发现了四个两个组件调节系统，每个系统都位于ABC转运蛋白系统附近。 Grars的一个系统之一，调节了包括ATPase和膜渗透酶的相邻VRAFG外排系统。 GRAR或VRAG中的突变导致对CAP的抗性降低，例如RP-1（来自血小板的PMP-1）和HNP-1（来自中性粒细胞），伊替迪辛和LL37。作为一种血管内病原体，金黄色葡萄球菌可能会遇到血小板和中性粒细胞（RP-1和HNP-1）的帽子，我们将重点关注该提案。金黄色葡萄球菌暴露于选择性上限也导致了基于诱导研究和微阵列分析的ABC转运蛋白基因（包括MPRF，DLTABCD以及另一组ABC Transporter基因VRADE）的诱导型Grars和VRAFG以及其他相关的帽耐药性。但是，这些基因对金黄色葡萄球菌中的支电阻介导的盖抗性的确切贡献尚未定义（AIM I）。此外，与表皮链球菌的表达相反，在任何瓶盖中都可以诱导Grars和vrafg的表达，因此金黄色葡萄球菌的诱导更具选择性，仅响应几个帽子。基于金黄色葡萄球菌和表皮链球菌之间的激酶传感器GRAS序列的差异，我们建议定义GRA中的确切残基，以介导这种识别特定帽的诱导下游基因的识别（AIM II）。除了细菌因素外，我们还对合成帽的结构及其结合和诱导Grars表达的能力感兴趣（AIM III）。最后，将在相关的感染性心内膜炎模型中探索这些发现中这些发现的体内相关性。这些研究将共同​​引起对金黄色葡萄球菌中相关宿主帽的先天抵抗的科学基础，从而提供了一种平台来设计策略，以减轻对阳离子抗菌肽的抵抗。 公共卫生相关性：金黄色葡萄球菌中对阳离子抗菌肽的先天抗性是这种有毒病原体的Armamentarium的一部分。这种耐药性从基因到金黄色葡萄球菌基因组而不是从外部获得的基因发展。我们发现编码两个组分调节系统和相邻转运蛋白基因的基因对于这种抗性很重要。我们建议定义这种抗性的机制。我们的长期目标是表征这些基因对阳离子抗菌肽的敏感性，以便我们将来可以设计更好的基于肽的抗生素。