The roles of Anaplasma phagocytophilum surface proteins in cellular invasion

嗜吞噬细胞无形体表面蛋白在细胞侵袭中的作用

• 批准号: 8510769
• 负责人: Jason A Carlyon
• 金额: $ 36.78万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-24 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8510769
• 关键词: Anaplasma phagocytophilum; Anaplasmataceae; Antisense RNA; Bacteria; Binding; Blood Vessels; Bovine Anaplasmosis; Cell Adhesion; Cells; Disease; Endothelial Cells; Equus caballus; Event; Genes; Germ Cells; Glycoproteins; Goals; Heart; Human; Infection; Infection prevention; Intervention; Invaded; Knock-out; Leukocytes; Liver; Mammalian Cell; Mediating; Membrane Proteins; Myeloid Cells; Opportunistic Infections; Organ; Organism; Predisposition; Proteins; Receptor Cell; Research; Risk; Role; Signal Transduction; Site-Directed Mutagenesis; Staging; Ticks; Transcript; Transgenic Organisms; Work; antimicrobial; cell type; design; feeding; gene function; interest; killings; knock-down; microbial; mutant; neutrophil; novel; novel strategies; pathogen; prevent; receptor; receptor binding; response; tool; uptake

DESCRIPTION (provided by applicant): Anaplasma phagocytophilum is an obligate intracellular bacterial pathogen that invades neutrophils and endothelial cells to cause the emerging and potentially fatal infection, human granulocytic anaplasmosis (HGA). A. phagocytophilum converts its host neutrophil into a Trojan Horse that facilitates pathogen replication and dissemination. It downregulates the neutrophil antimicrobial response, thereby raising susceptibility to opportunistic infections. Thus, blocking A. phagocytophilum infection of neutrophils would potentially prevent the stage of HGA associated with pathogen dissemination and increased risk of opportunistic infections. A. phagocytophilum infects microvascular endothelial cells of heart and liver. Endothelial cells are also implicated as the initial cell typ that A. phagocytophilum infects following inoculation via tick feeding. Infected endothelial cells are capable of transferring the bacterium to neutrophils. Therefore, abrogating A. phagocytophilum invasion of endothelial cells would potentially prevent infection of major organs and initial establishment of infection. The overall goal of this project is to identify and functioally characterize A. phagocytophilum outer membrane proteins that facilitate infection. We have identified outer membrane protein A (OmpA) and Asp14 (14-kDa Ap surface protein) as the first two A. phagocytophilum proteins that are critical for invasion of both myeloid cells and endothelial cells. In Aim 1, we will identify the OmpA and Asp14 domains that mediate A. phagocytophilum uptake and determine if either protein is sufficient for invasion. In Aim 2, we will identify the host cell receptors of OmpA and Asp14. In Aim 3, we will directly assess the relevance of OmpA and Asp14 to infectivity using novel transgenic A. phagocytophilum organisms that can be induced to express antisense RNA against ompA or asp14 to knock down OmpA or Asp14 expression. Achieving our goals will provide a robust understanding of A. phagocytophilum cellular invasion and identify the first two invasin-receptor pairs for any Anaplasmataceae pathogen. It will also yield a valuable tool for assessing gene function in obligate intracellular bacteria. Lastly, our work will potentially aid the design of novel intervenion strategies that target OmpA and Asp14 to prevent HGA by blocking multiple stages of infection.

描述（由申请人提供）：Anaplasma吞噬吞噬性是一种强制性细胞内细菌病原体，它侵入中性粒细胞和内皮细胞会导致出现的和潜在的致命感染，人类肉芽肿性肿瘤性异常肿瘤（HGA）。 A.吞噬细胞将其宿主中性粒细胞转化为促进病原体复制和传播的特洛伊木马。它下调中性粒细胞抗菌反应，从而提高了机会性感染的敏感性。因此，阻断嗜中性粒细胞的吞噬细胞的感染将有可能阻止与病原体传播相关的HGA阶段，并增加了机会性感染的风险。 A.吞噬细胞感染心脏和肝脏的微血管内皮细胞。内皮细胞也被视为初始细胞典型，即通过tick喂养接种后吞噬细胞嗜酸杆菌感染。感染的内皮细胞能够将细菌转移到中性粒细胞。因此，废除了内皮细胞的吞噬吞噬细胞侵袭将有可能阻止主要器官的感染和初始建立感染。该项目的总体目标是鉴定并在功能上表征促进感染的吞噬细胞藻外膜蛋白。我们已经将外膜蛋白A（OMPA）和ASP14（14-kDa AP表面蛋白）鉴定为前两个A.吞噬细胞蛋白，这对于侵入髓样细胞和内皮细胞至关重要。在AIM 1中，我们将确定介导吞噬细胞的摄取曲霉的OMPA和ASP14结构域，并确定任何一种蛋白质是否足以浸润。在AIM 2中，我们将确定OPMA和ASP14的宿主细胞受体。在AIM 3中，我们将使用新型的转基因吞噬细胞嗜生物体直接评估OMPA和ASP14与感染性的相关性，可引起对OMPA或ASP14表达反义RNA，以击倒OMPA或ASP14表达。实现我们的目标将提供对吞噬细胞杆菌细胞侵袭的强烈理解，并确定前两个入侵蛋白受体对，以确定任何厌食症病原体。它还将产生一种评估义务细胞内细菌基因功能的有价值的工具。最后，我们的工作将有助于设计针对OMPA和ASP14的新型中间策略，以通过阻止多个感染阶段来预防HGA。