Mechanisms of Vascular Leakage in Viral Hemorrhagic Fevers

病毒性出血热的发病率和死亡率主要是由血管渗漏及其 并发症。导致血管渗漏的机制尚未得到很好的表征。 该项目将继续研究登革热和汉坦病毒引起的血管渗漏是由一种 病毒刺激内皮细胞对T细胞源性炎性反应和 血管生成介质。第一个目标是描述在免疫系统中激活的早期先天免疫信号通路。 病毒刺激的人微血管内皮细胞，导致I型IFN的产生。I型IFN 介导内皮屏障功能的增强和抗血管生成作用。屏障功能将是 通过测量人微血管内皮细胞单层对大分子的渗透性来评估 (70 kDa葡聚糖）和小分子溶质（3 kDa葡聚糖）。早期血管生成 对人微血管内皮的作用将通过细胞/基质侵入测定来测量。第二 目的是描述关键的抗病毒T细胞反应和与内皮细胞相互作用的表型， 渗透性增强登革病毒和汉坦病毒特异性CD 4+和CD 8 + T细胞将被激活 并检测其调节血管内皮生长因子的能力 信号传导、渗透性和细胞侵袭。第三个目标将衡量 汉坦病毒感染患者血液样本中的炎症和血管生成标记物。复用 将对每日连续的血浆和尿液样本进行选定生物标志物的蛋白质免疫测定 从普马拉病毒（旧世界汉坦病毒）感染的患者收集。目标是发展一个 生物标志物“血管生成谱”可以预测疾病的严重程度和血管渗漏的发展。的 这种“血管生成特征”对病毒感染的微血管内皮通透性的影响将在 体外登革和汉坦病毒出血热发病机制中血管渗漏的更好理解 将导致新的诊断，治疗和预防这些病原体的方法。

The morbidity and mortality of viral hemorrhagic fevers are largely caused by vascular leakage and its ensuing complications. The mechanisms that lead to the vascular leakage have not been well characterized. This project will pursue the hypothesis that dengue and hantavirus-induced vascular leakage is caused by a temporal and differential responsiveness of virus-stimulated endothelium to T-cell derived inflammatory and angiogenic mediators. The first aim will delineate the early innate immune signaling pathways activated in virus-stimulated human microvascular endothelial cells that lead to Type I IFN production. Type I IFN mediates the enhancement of endothelial barrier function and anti-angiogenic effects. Barrier function will be assessed by measuring the permeability of human microvascular endothelial monolayers to macromolecules (70 kDa dextran) and small molecule solutes (3 kDa dextran) in a transwell assay system. Early angiogenic effects on human microvascular endothelium will be measured by a cell/matrix invasion assay. The second aim will delineate key anti-viral T-cell responses and phenotypes that interact with endothelium and lead to augmented permeability. Dengue virus and hantavirus-specific CD4+ and CD8+ T-cells will be activated under a variety of conditions and examined for their abilities to modulate vascular endothelial growth factor signaling, permeability, and cell invasion in the in vitro assays noted above. The third aim will measure inflammatory and angiogenic markers in blood samples from patients with hantavirus infections. Multiplex protein immunoassays for selected biomarkers will be performed on serial daily plasma and urine samples collected from patients with Puumala virus (Old World hantavirus) infections. The objective is to develop a biomarker "angiogenic profile" that can predict disease severity and development of vascular leakage. The effects of this "angiogenic profile" on virus-infected microvascular endothelium permeability will be tested in vitro. A better understanding of vascular leakage in dengue and hantavirus hemorrhagic fever pathogenesis will lead to new diagnostic, therapeutic, and preventive approaches to these pathogens.