Characterization of Anaplasma phagocytophilum adhesins

嗜吞噬细胞粘附素无形体的表征

• 批准号: 7921274
• 负责人: Jason A Carlyon
• 金额: $ 6.95万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-22 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7921274
• 关键词: Adherence; Adhesions; Affinity; Amino Acid Sequence; Anaplasma phagocytophilum; Anaplasmataceae; Bacteria; Bacterial Adhesins; Bacterial Adhesion; Binding; Biological Assay; Bovine Anaplasmosis; Cell Adhesion; Cell Communication; Cell surface; Cells; Complex; Cytolysis; Dependency; Development; Disease; Electrospray Ionization; Epitopes; Event; Family member; Fostering; Fucose; Genome; Glycoconjugates; Goals; HL-60 Cells; Human; Immune Sera; Individual; Inflammatory; Knowledge; Lead; Ligands; Light; Link; Mammals; Membrane Proteins; Microspheres; Modeling; N-terminal; Organism; P-selectin ligand protein; Paper; Pathogenesis; Peptides; Polysaccharides; Proteome; Recombinant Proteins; Recombinants; Reliance; Research; Selectins; Sialic Acids; Surface; Testing; Tick-Borne Infections; Ticks; Transcript; Tropism; United States; Variant; Work; base; glycosylation; human granulocytic ehrlichiosis; inhibitor/antagonist; liquid chromatography mass spectroscopy; member; neutrophil; novel; pathogen; prevent; sialyl Lewis x

DESCRIPTION (provided by applicant): Human granulocytic anaplasmosis (HGA; formerly human granulocytic ehrlichiosis) is an emerging and potentially fatal disease and the second most common tick-borne infection in the United States. The etiologic agent is Anaplasma phagocytophilum, an obligate intracellular bacterium that displays a unique tropism for neutrophils and neutrophil precursors. A. phagocytophilum adhesion to neutrophil surfaces involves recognition of P-selectin glycoprotein ligand-1 (PSGL-1) and sialyl Lewis x (sLex), a tetrasaccharide that modifies the N-terminus of PSGL-1 and other selectin ligands. Specifically, this recognition requires interactions with a PSGL-1 N-terminal peptide and alpha 2,3-linked sialic acid and alpha 1,3-linked fucose of sLex. We hypothesize that A. phagocytophilum uses multiple adhesins that cooperatively bind these determinants. Studies of A. phagocytophilum and other Anaplasmataceae family members suggest the A. phagocytophilum PSGL-1/ sLex-targeting adhesins are induced late in development and may require glycosylation and multimerization into adhesin complexes-for proper function. The objective of this proposal is to identify and characterize the individual adhesins that recognize PSGL-1, sialic acid, and fucose. The specific aims are: (1) identify candidate adhesins using affinity-based approaches; (2) identify adhesin candidates as upregulated or glycosylated outer membrane proteins; (3) test binding of putative adhesins to PSGL-1/ sLex glycoconjugates and cell surfaces. We have selected for an A. phagocytophilum adhesin variant, the adhesion of which is PSGL-1- and sialic acid-independent, but remains fucose-dependent. This variant will simplify identification of the fucose-specific adhesin and will aid adhesin hunting assays by circumventing the reliance of wild-type A. phagocytophilum on cooperative binding. Accomplishing these goals will shed light onto novel themes of bacteria-host cell interactions and will identify targets for treating or preventing HGA. Furthermore, these studies may lead to the development of new treatments for inhibiting cellular adhesion events associated with inflammatory disorders.

描述（由申请人提供）：人类粒细胞肿瘤病（HGA；以前的人类粒细胞ehrllichiois）是一种新兴的且潜在的致命疾病，是美国第二常见的tick虫感染。病因学是Anaplasma吞噬细胞的，这是一种强性的细胞内细菌，它显示出对中性粒细胞和中性粒细胞前体的独特的热带主义。 A.吞噬嗜中性粒细胞表面的吞噬性粘附涉及识别P-选择蛋白糖蛋白配体-1（PSGL-1）和siAllyl Lewis X（SLEX），这是一种修饰PSGL-1和其他SelectIn Ligands的N-末端。具体而言，这种识别需要与pSGL-1 N末端肽和α2,3连接的唾液酸和α相互作用的相互作用。我们假设吞噬曲霉使用多种粘附素可以合作结合这些决定因素。对吞噬细胞曲霉和其他无质抗科家族成员的研究表明，在发育后期诱导了吞噬细胞的pSGL-1/ SLEX靶向粘附素，可能需要糖基化和多糖基化，以多种形式化成粘附素络合物络合物络合物 - 合适的功能。该提案的目的是识别和表征识别psgl-1，唾液酸和岩藻糖的单个粘附素。具体目的是：（1）使用基于亲和力的方法鉴定候选粘合剂； （2）鉴定候选粘附素是上调或糖基化的外膜蛋白； （3）假定粘合剂与PSGL-1/ SLEX糖缀合物和细胞表面的测试结合。我们已经选择了一种吞噬细胞粒粘附素的变体，其粘附是pSGL-1-非依赖性的，但仍然依赖于岩藻糖。该变体将简化岩藻糖特异性粘附素的识别，并通过规避野生型A. phagocytophilum对合作结合的依赖，有助于狩猎粘合剂狩猎测定。实现这些目标将使细菌宿主相互作用的新主题阐明，并将确定治疗或预防HGA的目标。此外，这些研究可能导致开发新的治疗方法，以抑制与炎症性疾病相关的细胞粘附事件。