Complement-independent role of C4 binding protein in gonococcal survival from human neutrophils

C4 结合蛋白在人中性粒细胞淋球菌存活中的补体独立作用

• 批准号: 10307570
• 负责人: Alison K Criss
• 金额: $ 23.75万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-12-01 至 2023-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10307570
• 关键词: Affect; Antibiotics; Bacteria; Bacterial Infections; Binding; Binding Proteins; Cells; Characteristics; Complement; Cytoplasmic Granules; Deposition; Effectiveness; Exposure to; Exudate; Family; Family member; Gonorrhea; Gram-Negative Bacteria; Guanosine Triphosphate Phosphohydrolases; Health; Human; Immune; Immune Evasion; In Vitro; Individual; Infection; Inflammatory; Inflammatory Response; Ion-Exchange Chromatography Procedure; Knowledge; Lead; Lytic; Mass Spectrum Analysis; Measures; Mediating; Mucous Membrane; Muramidase; Natural Immunity; Neisseria gonorrhoeae; Neutrophil Activation; Neutrophil Infiltration; Peptide Hydrolases; Peptides; Phagocytes; Phagocytosis; Phagolysosome; Phase; Phosphatidylinositols; Phosphotransferases; Production; Proteins; Reactive Oxygen Species; Resistance; Respiratory Burst; Role; Serum; Sexually Transmitted Diseases; Signal Pathway; Signal Transduction; Surface; United States; Vaccines; Work; antimicrobial; antimicrobial peptide; antimicrobial resistant pathogen; carcinoembryonic antigen-related cell adhesion molecules; combat; complement 4b-binding protein; drug-resistant gonorrhea; experimental study; extracellular; genetic regulatory protein; gonorrhea vaccine; improved outcome; in vivo; neutrophil; novel; novel strategies; receptor; recruit; resistance frequency; response; therapy development; transmission process

PROJECT SUMMARY Neisseria gonorrhoeae (Gc) is a Gram-negative bacterium that causes the sexually transmitted disease gonorrhea. With an estimated 78 million cases of gonorrhea annually worldwide, increasing frequency of resistance to all recommended antibiotics, and the lack of a protective vaccine, N. gonorrhoeae is a prominent and growing threat to human health. A hallmark of Gc infection is the influx of neutrophils, but this inflammatory response is unsuccessful in clearing infection. Phase-variable opacity-associated (Opa) proteins on the Gc surface mediate non-opsonic phagocytosis by neutrophils. Expression of Opa proteins like OpaD of strain FA1090, which activates neutrophils by binding to the phagocytic receptors carcinoembryonic antigen-related cell adhesion molecule (CEACAM)-1 and CEACAM-3, significantly decreases Gc survival in the presence of human neutrophils in vitro. Neutrophils respond to OpaD+ Gc by generating reactive oxygen species, releasing toxic granule contents extracellularly, and internalizing the bacteria into a phagolysosome where they are killed by proteases and antimicrobial peptides. Despite being killed by neutrophils in vitro, Opa-expressing Gc survive and even predominate among Gc in neutrophil-rich gonorrheal exudates. As one explanation for these discordant findings, we have found that opsonization with human serum, which is found in inflammatory secretions, enhances Opa+ Gc survival from primary human neutrophils and suppresses the neutrophil oxidative burst. Through ion-exchange chromatography and mass spectrometry, we identified C4-binding protein (C4BP) as the serum component that binds to Opa+ Gc to limit neutrophil activation and increase Gc survival from neutrophils. Remarkably, these effects are independent of complement deposition or complement lytic activity, suggesting a novel mechanism by which binding of C4BP modulates neutrophil functions. In this proposal, we will define how C4BP mediates these effects on Opa+ Gc, by defining the molecular interactions between C4BP and the Gc surface and the cellular mechanisms that limit the response of human neutrophils to Opa+ Gc. Completion of this work will reveal a previously unappreciated way in which Opa+ Gc survives in neutrophil-rich secretions to enable its continued colonization as well as transmission to new hosts. With this knowledge, we predict that the development of therapies that interfere with C4BP binding to Gc will increase the efficacy of neutrophil antigonococcal activity, in addition to enhancing complement lytic activity, thereby improving outcomes of gonorrhea.

项目摘要 Neiserseria Gonorrhoeae（GC）是一种革兰氏阴性细菌，可引起性传播疾病 淋病。估计每年在世界范围内每年有7800万例淋病病例 对所有推荐抗生素的耐药性，以及缺乏保护性疫苗，N。Gono​​rrhoeae是突出的 以及对人类健康的威胁。 GC感染的标志是中性粒细胞的涌入，但这种炎症 反应在清除感染方面没有成功。 GC上的相变不透明度相关（OPA）蛋白 表面通过中性粒细胞介导非上吞噬作用。 OPA蛋白的表达如菌株的OPAD FA1090，通过与吞噬受体结合癌胚抗原相关的嗜中性粒细胞激活中性粒细胞 细胞粘附分子（CEACAM）-1和CEACAM-3，在存在的情况下显着降低了GC的存活率 人类嗜中性粒细胞体外。中性粒细胞通过产生活性氧对OPAD+ GC做出反应，释放 细胞外有毒颗粒含量，并将细菌内部化成吞噬体。 通过蛋白酶和抗菌肽。尽管在体外被嗜中性粒细胞杀死，但表达不透明的GC 在富含中性粒细胞的淋病渗出液中，GC生存，甚至占主导地位。作为这些解释 不和谐的发现，我们发现与人血清的调子化，这在炎症中发现 分泌，增强来自原发性人类嗜中性粒细胞的OPA+ GC的存活并抑制中性粒细胞 氧化爆发。通过离子交换色谱和质谱法，我们确定了C4结合 蛋白质（C4BP）作为与OPA+ GC结合以限制嗜中性粒细胞激活并增加GC的血清成分 中性粒细胞的生存。值得注意的是，这些影响与补体沉积或补体无关 裂解活性，提出了一种新的机制，通过该机制，C4BP的结合调节中性粒细胞功能。在这个 提案，我们将通过定义分子相互作用来定义C4BP如何介导这些对OPA+ GC的影响 在C4BP和GC表面以及限制人类嗜中性粒细胞反应的细胞机制之间 到OPA+ GC。这项工作的完成将揭示以前没有批准的方式，在这种方式中，OPA+ GC在其中生存 富含中性粒细胞的分泌物可以使其持续的殖民化以及向新宿主传播。与此 知识，我们预测，干扰C4BP结合GC的疗法的发展将增加 除了增强补体裂解活性之外 改善淋病的结果。