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广泛的人畜共患疾病，在城市贫民窟，特别是在热带地区，正在成为一种重要的传染病。钩端螺旋体属的几个物种可以引起感染，其严重程度从轻度疾病到致命的出血性疾病伴多器官衰竭不等。我们对钩端螺旋体致病机制的理解还有很大的差距，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是钩端螺旋体传播到几乎任何组织、持续定植在某些组织和引起内皮损伤的关键。特别地，致病性钩端螺旋体物种与特异性宿主细胞表面受体的结合可能对于细菌在宿主细胞中引起播散性感染和疾病的能力至关重要。 免疫活性宿主。与细胞表面分子的粘附也可能影响宿主细胞在直接环境中如何对病原体的存在做出反应，以及病原体如何侵入组织。然而，在这一点上，很少有人知道致病性钩端螺旋体细胞如何与宿主细胞表面相互作用。 我们发现L.问号结合内皮细胞表面受体比ECM更有效，VE-钙粘蛋白参与了这一活动。VE-钙粘蛋白是内皮完整性的主要介质。我们还确定了几种细胞特异性粘附素的基础上选择结合内皮细胞，两个f结合钙粘蛋白。此外，我们发现直接L.与内皮细胞结合的问号引起细胞单层的破坏，伴随着肌动蛋白细胞骨架的变化。这导致内皮细胞对细菌的渗透性增加，并可能反映了 广泛的内皮损伤是钩端螺旋体病病理生理学的一部分。我们现在提出测试的假设，具体L。问号线虫粘附素-VE-钙粘蛋白相互作用介导细菌附着于内皮细胞，导致内皮破坏。在目标1中，我们将检验L.问号线虫使用识别VE-钙粘蛋白的特异性蛋白质粘附素来介导与内皮层的附着和破坏。我们将进一步评估我们的候选粘附素在几个方面，包括确定他们是否赋予增加的哺乳动物细胞粘附活性，以非致病性L。biflexa。在目标2中，我们将确定L.使用生物化学、细胞生物学和遗传学方法对问号进行分析。我们将评估我们已经鉴定的细胞结合细菌粘附素在内皮层破坏中的作用。 本文提出的工作将显著推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有助于疾病的病理生理学的理解，可能会照亮疫苗开发或治疗的新候选者。