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最广泛的人畜共患病， 城市贫民窟，特别是热带地区的贫民窟中存在严重的传染病。的若干物种 钩端螺旋体属可引起感染，其严重程度从轻度疾病到致命的出血性疾病不等。 多器官功能衰竭典型地，维持（储库）宿主的感染是慢性的， 无症状。然而，同样的细菌可以引起急性，可能危及生命的感染， 偶然的宿主物种钩端螺旋体在野生动物、伴侣动物和牲畜中的持续存在 为人类感染提供了一个恒定的水库，因为受感染的动物在近端携带钩端螺旋体， 肾的小管和排泄钩端螺旋体在尿液中。将活细菌释放到 环境为新宿主的感染提供了机会。感染是通过暴露于 动物体液，特别是尿液，或来自被尿液污染的环境来源。条目 典型地通过粘膜或皮肤中的小裂口，随后传播至 多个站点。广泛的内皮损伤是钩端螺旋体病的显著特征。 尽管全球疾病负担沉重，但钩端螺旋体属物种的致病机制是 替补演员粘附到宿主分子上对于许多病原体建立 感染并导致疾病，对于钩端螺旋体来说也是如此。粘附于宿主细胞表面 分子可以促进组织的侵入，但迄今为止，这个问题还没有被机械地 已解决。虽然已经鉴定了几种候选的粘附蛋白，但是这些活性是如何产生的呢？ 导致体内致病性仍然未知。 我们证明了内皮细胞-细胞连接的主要贡献者，VE-钙粘蛋白，是一种受体， 李斯特质问者我们还鉴定了两种与VE-钙粘蛋白结合的粘附素，证明L。 问号和纯化的重组粘附素引起粘附连接的破坏， 对维持内皮完整性至关重要。在我们对另一种螺旋体，伯氏疏螺旋体的研究中， 我们开发了短期静脉接种模型来确定B的作用。burgdorferi 蛋白质与活体小鼠不同组织部位的血管系统相互作用。在这 探索/发展项目，我们将测试的假设，具体L。问号蛋白 有助于体内细菌与内皮的相互作用。在目标1中，我们将检验以下假设： L.在活体动物中，问号线虫与血管内皮相互作用，在目标2中，我们将测试 假设特异性L.在体外粘附VE-钙粘蛋白的问号蛋白在以下方面具有作用： 细菌在体内对内皮的粘附。这一探索性/发展性工作将完善 三个L.问号线虫粘附素参与钩端螺旋体病的发病机制。

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.