Host factors and viral determinants mediating flavivirus NS1 tissue-specific endothelial dysfunction and vascular leak

宿主因子和病毒决定簇介导黄病毒NS1组织特异性内皮功能障碍和 血管渗漏 摘要 黄病毒(FV)属含有重要的医学上由蚊子传播的人类病原体，这些病原体会导致主要的 全球疾病负担。而登革热(DENV)、黄热病(YFV)和寨卡病毒(ZIKV)是系统性的，以及 西尼罗河病毒(WNV)、日本脑炎(JEV)和寨卡病毒会引起嗜神经性感染，每种FV都可以 导致严重的疾病，部分特征是内皮屏障功能障碍--最典型的例子是 严重登革热的血管渗漏。这可能是血管活性细胞因子和病毒过度产生的结果。 各种因素。高度保守的FV非结构蛋白1(NS1)由感染细胞分泌并在 受感染的人类的血液。我们和其他人已经证明FV NS1可以触发内皮屏障的破坏 在体外和小鼠血管内渗漏，独立于病毒感染。在我们目前的R01中，我们展示了远藤- FVNS1细胞分化为内皮细胞后组织蛋白酶、L和 乙酰肝素酶导致内皮细胞糖帽层(EGL)破坏和细胞间错误定位 连接蛋白，两者都对维持内皮屏障的完整性至关重要。有趣的是，我们发现FV NS1 蛋白质表现出精致的组织趋向性，在体外和体内引发EC功能障碍，反映了 每种病毒的组织嗜性和疾病表现。而Fv NS1的组织趋向性是由 不同的EC结合和内化，关键酶和信号通路的下游激活 致病所需似乎在FVS中是保守的。然而，宿主因素、病毒决定因素和 调节这些过程的机制尚不清楚。我们假设组织上的不同宿主因素- 特异性内皮细胞介导FV NS1细胞结合和内化，导致内皮屏障功能障碍，病毒 传播，以及不同的FV病表现。相反，一旦FV NS1蛋白被内化，我们 假设EC功能障碍的下游步骤是可比的--从而为泛FV指明了方向 干预。在这里，我们通过识别和表征宿主多糖、蛋白质、 人、小鼠内皮细胞中NS1的组织特异性结合和内化所需的NS1决定因素 模型和临床样本。我们还定义了FV NS1蛋白触发的常见机制 病理学。在目标1中，我们将识别和表征宿主多糖和FV NS1决定簇，以实现不同的- 与组织特异性内皮细胞的亲和性结合。在目标2中，我们将识别启动所需的蛋白质类ns1受体 EC功能障碍与Fv NS1蛋白介导EGL和细胞间损伤的机制 组织特异性内皮细胞在体外和体内的连接。目的3研究FV NS1介导的内皮细胞的影响 严重急性呼吸综合征小鼠模型和人类临床标本中FV传播和发病机制的功能障碍 越南、尼加拉瓜和巴西的登革热和YF患者。这项工作得到了糖生物学专家的支持 结构生物学和生物化学、血管生物学、FV发病机制和动物模型以及临床 调查并应确定严重FV疾病的生物标记物以及新的病毒和宿主治疗靶点。

Host factors and viral determinants mediating flavivirus NS1 tissue-specific endothelial dysfunction and vascular leak ABSTRACT The flavivirus (FV) genus contains medically important mosquito-borne human pathogens that cause a major global disease burden. While dengue (DENV), yellow fever (YFV), and Zika (ZIKV) viruses are systemic, and West Nile (WNV), Japanese encephalitis (JEV), and Zika viruses cause neurotropic infections, each FV can cause severe disease characterized in part by endothelial barrier dysfunction – the most classic example being vascular leak in severe dengue. This may result from overproduction of vasoactive cytokines as well as viral factors. The highly conserved FV non-structural protein 1 (NS1) is secreted from infected cells and circulates in the blood of infected humans. We and others have shown that FV NS1 can trigger endothelial barrier disruption in vitro and vascular leak in mice, independently from virus infection. In our current R01, we showed that endo- cytosis of FV NS1 into endothelial cells (ECs) followed by activation of key enzymes such as cathepsin L and heparanase leads to disruption of the endothelial glycocalyx layer (EGL) as well as mislocalization of intercellular junction proteins, both critical for maintaining endothelial barrier integrity. Interestingly, we found that FV NS1 proteins display exquisite tissue tropism, triggering EC dysfunction in vitro and in vivo in a manner reflecting tissue tropism and disease manifestations of each virus. While FV NS1 tissue tropism was determined by differential EC binding and internalization, downstream activation of key enzymes and signaling pathways required for pathogenesis appear to be conserved across FVs. However, host factors, viral determinants, and mechanisms mediating these processes are unknown. We hypothesize that distinct host factors on tissue- specific ECs mediate FV NS1 cell binding and internalization, leading to endothelial barrier dysfunction, virus dissemination, and different FV disease manifestations. In contrast, once a FV NS1 protein is internalized, we hypothesize that downstream steps of EC dysfunction are comparable – thus pointing the way to a pan-FV intervention. Here, we expand our previous work by identifying and characterizing host glycans, proteins, and NS1 determinants required for tissue-specific cell binding and internalization of NS1 in human ECs, mouse models, and clinical samples. We also define common mechanisms by which FV NS1 proteins trigger pathology. In Aim 1, we will identify and characterize host glycans and FV NS1 determinants required for differ- ential binding to tissue-specific ECs. In Aim 2, we will identify proteinaceous NS1 receptors required to initiate EC dysfunction and define mechanisms by which FV NS1 proteins mediate disruption of the EGL and intercellular junctions in tissue-specific ECs in vitro and in vivo. Aim 3 investigates the impact of FV NS1-mediated endothelial dysfunction on FV dissemination and pathogenesis in mouse models and human clinical samples from severe dengue and YF patients in Vietnam, Nicaragua and Brazil. This work is supported by experts in glycobiology, FV structural biology and biochemistry, vascular biology, FV pathogenesis and animal models, and clinical investigation and should identify biomarkers of severe FV disease and novel viral and host therapeutic targets.