Molecular basis and intervention of Staphylococcus aureus agglutination

金黄色葡萄球菌凝集的分子基础及干预

• 批准号: 9180674
• 负责人: Dominique M. Missiakas
• 金额: $ 38.94万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-01 至 2019-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9180674
• 关键词: Abscess; Adhesions; Agglutination; Antibiotics; Aspartate; Bacteremia; Bacteria; Binding; Blocking Antibodies; Blood; Bypass; Calcium; Cell Wall; Cells; Chelating Agents; Clinical; Coagulation Process; Coenzyme A; Communities; Disease; Drug resistance; Electrons; Encapsulated; Endothelial Cells; Endothelium; Event; Factor XIII; Fibrin; Fibrinogen; Fibronectins; Fluorescein; Genes; Genetic; Genus staphylococcus; Human; Immune; In Vitro; Incubated; Intervention; Label; Lesion; Mediating; Methicillin Resistance; Microscope; Modeling; Modification; Molecular; Monoclonal Antibodies; Multiprotein Complexes; Mus; Organ; Pathogenesis; Pathway interactions; Patients; Phagocytes; Phagocytosis; Phenotype; Plasma; Post-Translational Protein Processing; Prothrombin; Recruitment Activity; Resistance; Sepsis; Serine; Skin; Skin Tissue; Soft Tissue Infections; Splanchnic Circulation; Staphylococcus aureus; Staphylococcus epidermidis; Surface; Survival Rate; Symbiosis; Therapeutic antibodies; Time; Tissues; Transferase; Vascular Endothelium; Virulence; Work; base; crosslink; factor A; gene product; in vivo; killings; loss of function; micrography; mortality; mouse model; pathogen; prevent; public health relevance; reconstitution; release factor; small molecule inhibitor; sortase; von Willebrand Factor

DESCRIPTION (provided by applicant): Staphylococcus aureus, a commensal of the human skin and nares, is also an invasive pathogen and frequent cause of skin and soft tissue infections, bacteremia and sepsis. Many clinical isolates are resistant against commonly used antibiotics and these strains are collectively referred to as methicillin-resistant S. aureus (MRSA). The annual survival rate of patients with MRSA sepsis is less than 50%. S. aureus is the only bacterial pathogen known to coagulate plasma and to agglutinate with fibrin cables in blood. We show here that this agglutination phenotype is based on the secreted products from three genes (coa, vwb, clfA) as well as several non-secreted gene products. We propose a new model whereby S. aureus agglutination involves the formation of staphylothrombin (Coa, vWbp)-assembled fibrin cables, which are capped by clumping factor A (ClfA) on the staphylococcal surface and crosslinked by factor XIII. We hypothesize that S. aureus agglutination provides for escape from phagocytic killing. Further, vWbp-mediated recruitment of von Willebrand Factor (vWF) provides a tether for endothelial cells and supports bacterial traffic out of the vasculature thereby promoting S. aureus dissemination to organ tissues where staphylococci replicate as a bacterial community, protected from immune cells. This key virulence strategy may be perturbed with monoclonal antibodies and small molecule inhibitors to either prevent or treat S. aureus sepsis. Preliminary work demonstrated that S. aureus Coa and vWbp each associate with host prothrombin to form multi-protein complexes in human plasma (with prothrombin, fibrinogen, fibronectin and factor XIII) dedicated to the formation of cross-linked fibrin cables. Staphylococcal agglutination involves the surface display of functional ClfA, which requires several gene products [aggABCD, (staphylococcal agglutination genes)] that appear to modify ClfA prior to sortase A-mediated anchoring in the bacterial cell wall envelope (srtA). In addition to genetic loss-of-function analysis, we will also reconstitute agglutination in vitro from purifie components and in vivo by expressing genes in Staphylococcus epidermidis, an opportunistic pathogen that cannot agglutinate or form discrete abscess lesions. Monoclonal antibodies (mAbs) -isolated against purified Coa, vWbp or ClfA- and small molecule inhibitors are being used to perturb staphylococcal agglutination in vitro and in vivo and examined for the provision of protection or therapy in a mouse model of S. aureus sepsis.

描述（由申请人提供）：金黄色葡萄球菌是人类皮肤和纳雷斯的共生，也是侵入性的病原体，是皮肤和软组织感染，菌血症和败血症的频繁原因。许多临床分离株对常用抗生素具有抗性，这些菌株统称为耐甲氧西林的金黄色葡萄球菌（MRSA）。 MRSA败血症患者的年生存率小于50％。金黄色葡萄球菌是唯一已知的细菌病原体，可以凝结血浆并用血液中的纤维蛋白电缆凝集。我们在这里表明，这种凝集表型基于来自三个基因（COA，VWB，CLFA）的分泌产物以及几种非分泌基因产物。我们提出了一个新模型，金黄色葡萄球菌凝集涉及形成葡萄球菌蛋白（COA，VWBP）组装的纤维蛋白电缆，这些电缆由葡萄球菌表面上的块状因子A（CLFA）覆盖，并由因子XIIII交叉链接。我们假设金黄色葡萄球菌的凝集可以逃避吞噬杀戮。此外，VWBP介导的von Willebrand因子（VWF）的募集为内皮细胞提供了一个束缚，并支持脉管系统中的细菌流量，从而促进金黄色葡萄球菌传播到器官组织中，其中葡萄球菌复制为细菌群落，并受到免疫细胞的保护。这种关键的毒力策略可能会被单克隆抗体和小分子抑制剂扰动，以预防或治疗金黄色葡萄球菌败血症。初步工作表明，金黄色葡萄球菌和VWBP各自与宿主凝血酶原相关联，以形成人血浆中的多蛋白质复合物（与凝血酶原，纤维蛋白原，纤维蛋白原和因子XIII）相结合，可用于交叉链接的Fibrin Cocables的形成。葡萄球菌凝集涉及功能性CLFA的表面表现，它需要几种基因产物[AggaBCD，（葡萄球菌凝集基因）]，它们似乎在细菌细胞壁包膜（SRTA）中锚定在细菌细胞壁包膜（SRTA）之前对CLFA进行了修饰。除了遗传功能丧失分析外，我们还将通过表达表皮葡萄球菌中的基因来重新构成体外的凝集，并在体内重新凝集，这是一种机会性的病原体，该病原体无法凝结或形成离散的脓肿病变。抗纯化的COA，VWBP或CLFA和小分子抑制剂的单克隆抗体（mAb）用于在体外和体内诱导葡萄球菌凝集凝集，并在体外检查并检查了在aureus s. aureus sepsis的小鼠模型中提供保护或治疗的。