Mechanisms of Leptospira interrogans interactions with the vascular endothelium in vivo

摘要 钩端螺旋体病是世界范围内传播最广泛的人畜共患病，并继续以一种 城市贫民窟中的重大传染病，特别是在热带地区。几个物种的 钩端螺旋体属可引起感染，其严重程度从轻微疾病到致命出血不等。 伴有多器官衰竭的疾病。通常情况下，维持性(水库)宿主的感染是慢性的 没有任何症状。然而，同样的细菌可以引起急性的，潜在威胁生命的感染 意外的寄主物种。钩端螺旋体在野生动物、伴生动物和家畜中的持久性 为人类感染提供了一个持续的蓄水池，因为受感染的动物在近端有钩端螺旋体 肾脏的小管，并在尿液中排泄钩端螺旋体。将活细菌释放到 环境为新宿主的感染提供了机会。感染是通过接触以下物质获得的 动物体液，尤指尿液，或来自被尿液污染的环境来源。条目为 通常通过粘膜或皮肤上的小裂口，然后扩散到 多个站点。广泛的内皮损伤是钩端螺旋体病的一个显著特征。 尽管存在全球性的疾病负担，但钩端螺旋体的致病机制是 未得到充分研究。对宿主分子的黏附对于许多病原体建立 感染和致病，对钩端螺旋体也可能是如此。与宿主细胞表面的黏附 分子可能促进组织的入侵，但到目前为止，这个问题还不是机械性的。 地址。虽然已经确定了几种候选黏附蛋白，但这些活性是如何 对体内致病性的贡献尚不清楚。 我们证明了内皮细胞-细胞连接的主要贡献者VE-钙粘附素是一种受体 对于被审讯者来说。我们还鉴定了两种与VE-钙粘附素结合的粘附素，证明了L. 提纯的重组粘附素和提纯的重组粘附素会导致粘连连接的破坏，这是 对于维持内皮细胞的完整性至关重要。在我们对另一种螺旋体伯氏疏螺旋体的研究中， 我们开发了一种短期静脉接种模型来确定伯氏杆菌的作用。 活体小鼠不同组织部位与血管系统相互作用的蛋白质。在这 探索/发展项目，我们将检验特定的问号李斯特菌蛋白的假设 有助于体内细菌与内皮细胞的相互作用。在目标1中，我们将检验假设 问号钩端螺旋体与活体动物的血管内皮细胞相互作用，在目标2中，我们将测试 假设体外粘附VE-钙粘附素的特定问号钩端螺旋体蛋白在 细菌在体内对内皮细胞的黏附。这项探索性/开发性工作将使 三种问号钩端螺旋体粘附素在钩端螺旋体病发病中的作用机制。

Abstract Leptospirosis is the most widespread zoonotic disease worldwide, and continues to emerge as a significant infectious disease in urban slums, particularly in tropical regions. Several species of the genus Leptospira can cause infection, which varies in severity from mild illness to fatal hemorrhagic disease with multiple organ failure. Typically, infection of a maintenance (reservoir) host is chronic and asymptomatic. Yet, the same bacterium can cause acute, potentially life-threatening infection in an accidental host species. Persistence of leptospires in wildlife, companion animals, and livestock provides a constant reservoir for human infection, as infected animals harbor Leptospira in the proximal tubules of the kidney and excrete Leptospira in the urine. Release of viable bacteria into the environment provides opportunities for infection of new hosts. Infection is acquired through exposure to animal bodily fluids, especially urine, or from environmental sources contaminated with urine. Entry is typically through mucous membranes or minor breaches in the skin, followed by dissemination to multiple sites. Widespread endothelial damage is a prominent feature of leptospirosis. Despite the global burden of disease, the pathogenic mechanisms of Leptospira species are understudied. Adhesion to host molecules is critical to the abilities of many pathogens to establish infection and cause disease, and is likely true for Leptospira, as well. Adhesion to host cell surface molecules may facilitate invasion of tissues, but to date this question has not been mechanistically addressed. While several candidate adhesive proteins have been identified, how these activities contribute to pathogenicity in vivo remains unknown. We demonstrated that the major contributor to endothelial cell-cell junctions, VE-cadherin, is a receptor for L. interrogans. We also identified two adhesins that bind to VE-cadherin, demonstrated that L. interrogans and purified recombinant adhesins cause disruption of adherens junctions, which are critical to maintenance of endothelial integrity. In our work on another spirochete, Borrelia burgdorferi, we developed a short-term intravenous inoculation model to determine the roles of B. burgdorferi proteins in interactions with the vasculature in different tissue sites in living mice. In this exploratory/developmental project, we will test the hypothesis that specific L. interrogans proteins contribute to bacterial interaction with the endothelium in vivo. In Aim 1 we will test the hypothesis that L. interrogans interacts with the vascular endothelium in living animals, and in Aim 2 we will test the hypothesis that specific L. interrogans proteins that adhere to VE-cadherin in vitro have roles in adherence of the bacteria to the endothelium in vivo. This exploratory/developmental work will refine the mechanism by which three L. interrogans adhesins contribute to the pathogenesis of leptospirosis.