Inhibition of the Classical & Lectin Complement Pathways by Staphylococcus aureus Eap

古典的抑制

基本信息

批准号：
8891551
负责人：
Brian V Geisbrecht
金额：
$ 18.75万
依托单位：
KANSAS STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-01-01 至 2016-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8891551
关键词：
Active Sites Acute Adherence Affinity Anti-Inflammatory Agents Anti-inflammatory Autoimmune Diseases Bacteria Basic Science Binding Binding Sites Biochemical Biological Assay Cell surface Chronic Complement Complement 3 Convertase Complement 3b Complement 4b Complement Activation Complement Inactivators Complex Cyclic Peptides Development Disease Dose Enzymes Event Extracellular Domain Extracellular Protein FDA approved Foundations Future Generations Goals Graft Rejection Human Human body Hyperactive behavior Immunity Inflammation Inflammation Mediators Inflammatory Intervention Investigation Lead Lectin Libraries Malignant Neoplasms Mediating Modeling Molecular Mutagenesis Nature Neurodegenerative Disorders Pathway interactions Peptide Hydrolases Peptides Phage Display Pharmaceutical Preparations Play Price Process Protein Binding Protein Family Protein Inhibition Proteins Rare Diseases Regulation Reperfusion Injury Role Route Sepsis Syndrome Series Serine Protease Serpins Site Specificity Staphylococcus aureus Structure Structure-Activity Relationship System Therapeutic Virulent Whole Blood Work alternative pathway complement C3 convertase base biomaterial incompatibility complement 4b-binding protein complement C2a complement C3 precursor complement C4c complement pathway complement system design driving force extracellular human disease inhibitor/antagonist insight member neutrophil novel novel strategies pathogen protein structure function public health relevance response screening therapeutic target

项目摘要

DESCRIPTION (provided by applicant): Over the last several years, our understanding of the complement evasion mechanisms utilized by pathogens has increased precipitously through the study of the virulent bacterium Staphylococcus aureus. By screening a library of secreted S. aureus proteins in a human whole-blood model of inflammation, we have identified the Extracellular Adherence Protein (Eap) as the first known S. aureus inhibitor of the Classical (CP) and Lectin (LP) pathways of complement. Eap inhibits both of these pathways in a dose-dependent manner that requires formation of high-nanomolar affinity interaction with complement component C4b. This interaction blocks formation of the CP/LP pro-C3 convertase complex (C4b/C2), which dramatically lowers levels of the active CP/LP C3 convertase (C4b/C2a). Using the same whole-blood model, we have also identified Eap as a potent inhibitor of Neutrophil Serine Proteases (NSPs). Unlike conventional serpins, Eap inhibition of NSPs is non-covalent in nature. Furthermore, it occurs through a molecular mechanism distinct from its effects on the complement system since two related proteins, EapH1 and EapH2, also block NSP activity but have no effect on complement. In this proposal, we will investigate the molecular basis for the specificity of Eap's effects on the CP/LP through two Specific Aims: (1) We will characterize the biochemical and structural basis for Eap binding to complement protein C4b, and (2) We will characterize peptides that compete with Eap for C4b binding and determine whether they retain Eap-like inhibitory activities against the CP/LP. We expect that this integrated structure/function and discovery approach will provide new insight into regulation of the CP/LP. In turn, this may hold important clues into the design and optimization of novel complement-targeted, anti-inflammatory therapeutics in the future.

描述（由适用提供）：在过去的几年中，我们对病原体使用的完成机制的理解可以通过研究毒细菌的葡萄球菌精确提高。通过筛选人类炎症全血的分泌金黄色葡萄球菌蛋白的库，我们已经确定了细胞外粘着蛋白（EAP）是首个已知的经典金黄色葡萄球菌抑制剂（CP）（CP）和凝集素（LP）（LP）途径。 EAP以剂量依赖性的方式抑制这两种途径，该途径需要形成高纳摩尔亲和力与完成成分C4B的相互作用。这种相互作用阻止了CP/LP Pro-C3转化酶复合体（C4B/C2）的形成，该复合体（C4B/C2）大大降低了活性CP/LP C3转化酶（C4B/C2A）的水平。使用相同的全血模型，我们还将EAP确定为嗜中性粒细胞蛋白酶（NSP）的潜在抑制剂。与常规的Serpins不同，NSP的EAP抑制本质上是非共价的。此外，它通过与其对完成系统的影响不同的分子机制发生，因为两个相关的蛋白质EAPH1和EAPH2也阻止了NSP活性，但对完成没有影响。在此提案中，我们将通过两个具体目的研究EAP对CP/LP影响的特异性的分子基础：（1）我们将表征EAP与补体蛋白C4B结合的生化和结构基础，并且（2）我们将与C4B结合的EAP竞争并确定其与c4b bignition Aep/aep eap eap aep sike aep sike np sike np inp sike inp sike np sike np inp sike np inp sike inp sike np inp sike inp sike inp sike inp sike。我们预计，这种集成的结构/功能和发现方法将为CP/LP的调节提供新的见解。反过来，这可能会为未来的新型完全靶向抗炎疗法的设计和优化提供重要的线索。