Leptospira interrogans Interactions with Endothelial Cells

问号钩端螺旋体与内皮细胞的相互作用

• 批准号: 8917853
• 负责人: Jenifer L Coburn
• 金额: $ 38.25万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-27 至 2018-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8917853
• 关键词: Actins; Acute; Adhesions; Affect; Affinity; Animals; Bacteria; Bacterial Adhesins; Bacterial Infections; Binding; Biochemical; Biological; Cadherins; Cell Adhesion; Cell Surface Receptors; Cell surface; Cells; Chronic; Communicable Diseases; Cytoskeleton; Development; Disease; E-Cadherin; Endothelial Cells; Endothelium; Environment; Evaluation; Exposure to; Extracellular Matrix; Functional disorder; Future; Goals; Health; Human; Immunocompetent; Incidence; Infection; Intercellular Junctions; Invaded; Knowledge; Lead; Leptospira; Leptospira interrogans; Leptospirosis; Life; Liquid substance; Livestock; Lyme Disease; Maintenance; Mammalian Cell; Mediating; Mediator of activation protein; Minor; Molecular; Molecular Genetics; Mucous Membrane; Multiple Organ Failure; Permeability; Play; Proteins; Proximal Kidney Tubules; Receptor Cell; Role; Severities; Skin; Slum; Soil; Source; Surface; Testing; Therapeutic; Therapeutic Intervention; Tissues; Urine; Vaccine Therapy; Vascular Permeabilities; Water; Work; base; burden of illness; cadherin 5; companion animal; genetic approach; genetic manipulation; improved; insight; monolayer; novel; pathogen; receptor; receptor binding; vaccine development

DESCRIPTION (provided by applicant): Leptospirosis is the most widespread zoonotic disease worldwide, and is emerging as a significant infectious disease in urban slums, particularly in tropical regions. Several species of the genus Leptospira can cause infection, which can vary in severity from mild illness to fatal hemorrhagic disease with multiple organ failure. There is a significant gap in our understanding of the pathogenic mechanisms of Leptospira species, but adhesion to host cell surfaces, extracellular matrix (ECM) components, and soluble host molecules is likely to be critical for Leptospira species to disseminate to virtually any tissue, persistently colonize certain tissues, and cause endothelial damage. In particular, binding of pathogenic Leptospira species to specific host cell- surface receptors is likely to be critical to the ability of the bacteria to cause disseminated infection and disease in immunocompetent hosts. Adhesion to cell surface molecules may also affect how the host cell(s) in the immediate environment respond to the presence of the pathogen, and how the pathogen invades tissues. At this point, however, little is known about how pathogenic Leptospira cells interact with host cell surfaces. We found that L. interrogans binds to endothelial cell surface receptors more efficiently than to ECM, and that VE-cadherin participates in this activity. VE-cadherin is the major mediator of endothelial integrity. We also identified several cell-specific adhesins based on selection for binding to endothelial cells, two f which bind to cadherins. In addition, we found that direct L. interrogans binding to endothelial cells causes disruption of the cell monolayers, concomitant with changes in the actin cytoskeleton. This leads to increased endothelial permeability to the bacteria, and likely reflects the widespread endothelial damage that is part of the pathophysiology of leptospirosis. We now propose to test the hypothesis that specific L. interrogans adhesin- VE-cadherin interactions mediate bacterial attachment to endothelial cells, resulting in disruption of the endothelium. In Aim 1, we will test the hypothesis that L. interrogans uses specific protein adhesins that recognize VE-cadherin to mediate attachment to, and disruption of, endothelial layers. We will further evaluate our candidate adhesins in several ways, including determining whether they confer increased mammalian cell adhesion activity to non-pathogenic L. biflexa. In Aim 2, we will determine the mechanism of endothelial disruption by L. interrogans using biochemical, cell biological and genetic approaches. The roles of the cell- binding bacterial adhesins we have identified in endothelial layer disruption will be evaluated. The work proposed here will significantly advance our understanding of how pathogenic Leptospira species interact with host cell surface receptors to cause infection and how these interactions contribute to the pathophysiology of disease, may illuminate new candidates for vaccine development or therapeutics.

描述（由申请人提供）：钩端螺旋体病是世界范围内最普遍的人畜共患疾病，并且正在成为城市贫民窟中的一种重要传染病，特别是在热带地区。钩端螺旋体属的几种物种可引起感染，感染的严重程度从轻微疾病到伴有多器官衰竭的致命出血性疾病不等。我们对钩端螺旋体的致病机制的理解存在很大差距，但对宿主细胞表面、细胞外基质（ECM）成分和可溶性宿主分子的粘附可能对于钩端螺旋体传播到几乎任何组织、持续定植某些组织并引起内皮损伤至关重要。特别是，致病性钩端螺旋体物种与特定宿主细胞表面受体的结合可能对于细菌引起播散性感染和疾病的能力至关重要。 免疫能力强的宿主。对细胞表面分子的粘附还可能影响直接环境中的宿主细胞如何响应病原体的存在，以及病原体如何侵入组织。然而，目前人们对致病性钩端螺旋体细胞如何与宿主细胞表面相互作用知之甚少。 我们发现问号钩端螺旋体与内皮细胞表面受体的结合比与 ECM 的结合更有效，并且 VE-钙粘蛋白参与了这种活性。 VE-钙粘蛋白是内皮完整性的主要介质。我们还根据与内皮细胞结合的选择鉴定了几种细胞特异性粘附素，其中两种与钙粘蛋白结合。此外，我们发现问询钩端螺旋体直接与内皮细胞结合会导致细胞单层破坏，同时肌动蛋白细胞骨架发生变化。这导致内皮细胞对细菌的通透性增加，并可能反映 广泛的内皮损伤是钩端螺旋体病病理生理学的一部分。我们现在提议检验以下假设：特定问号钩端螺旋体粘附素-VE-钙粘蛋白相互作用介导细菌附着于内皮细胞，导致内皮细胞破坏。在目标 1 中，我们将检验这样的假设：问号钩体使用识别 VE-钙粘蛋白的特定蛋白质粘附素来介导内皮层的附着和破坏。我们将以多种方式进一步评估我们的候选粘附素，包括确定它们是否赋予非致病性双弯乳杆菌增加哺乳动物细胞粘附活性。在目标 2 中，我们将使用生化、细胞生物学和遗传学方法确定问号钩体破坏内皮细胞的机制。我们将评估我们已鉴定的细胞结合细菌粘附素在内皮层破坏中的作用。 这里提出的工作将显着增进我们对致病性钩端螺旋体物种如何与宿主细胞表面受体相互作用以引起感染以及这些相互作用如何促进疾病的病理生理学的理解，可能会阐明疫苗开发或治疗的新候选者。