Heparan sulfate proteoglycans initiate dengue virus infection of hepatocytes
Heparan sulfate proteoglycans initiate dengue virus infection of hepatocytes
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DOI：
10.1053/jhep.2000.18713
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发表时间：
2000-11-01
期刊：
影响因子：
13.5
通讯作者：
Stockert, R
中科院分区：
文献类型：
--
作者：
Hilgard, P;Stockert, R
登革病毒（DEN）引起广泛的临床表现，包括潜在的危及生命的疾病，如出血性休克综合征和较不常见的急性肝炎伴肝衰竭和脑病。此外，登革热病毒提供了一个潜在的模型，以了解肝细胞感染的启动结构密切相关的丙型肝炎病毒（HCV），因为这种病毒目前不能在细胞培养物中生长。虽然病毒感染的初始步骤是组织嗜性的关键决定因素，因此发病机制，很少有人知道的结合和内吞运输的DEN或任何其他黄病毒的分子基础。我们的研究表明，放射性标记的DEN与人肝癌细胞系HuH-7的结合是严格的pH依赖性的，并且基本上可被糖胺聚糖肝素所抑制。作为病毒覆盖测定进行的配体印迹分析显示，两种含有硫酸乙酰肝素（HS）的细胞表面结合蛋白在33和37 kd处分辨。基于未保护的病毒和细胞表面上的病毒结合位点对胰蛋白酶的敏感性，病毒内化被定量为胰蛋白酶保护的病毒随时间的增加。通过网格蛋白外壳的pH解离和依赖于IP 3介导的同型内体融合抑制病毒运输到降解位点。这些发现证实了肝细胞对DEN的结合和内化主要由含有蛋白多糖的IIS介导的假设，并表明黄病毒在感染期间运输主要的网格蛋白依赖性内吞途径。
Dengue viruses (DEN) cause a broad spectrum of clinical manifestations including potentially life-threatening conditions such as hemorrhagic shock syndrome and less frequently acute hepatitis with liver failure and encephalopathy. In addition, dengue viruses provide a potential model to understand the initiation of hepatocyte infection by the structurally closely related hepatitis C virus (HCV), because this virus at present cannot be grown in cell culture. Although the initial steps of viral infection are a critical determinant of tissue tropism and therefore pathogenesis, little is known about the molecular basis of binding and endocytic trafficking of DEN or of any other flavivirus. Our studies revealed that binding of radiolabeled DEN to the human hepatoma cell line HuH-7 was strictly pH dependent and substantially inhibitable by the glycosaminoglycan heparin. ligand-blot analysis, performed as a viral overlay assay, showed two heparan sulfate (HS) containing cell-surface binding proteins resolving at 33 and 37 kd, Based on the sensitivity of unprotected virus and the viral binding site on the cell surface to trypsin, viral internalization was quantified as an increase in trypsin protected virus over time. Virus trafficking to the site of degradation was inhibited by pH dissociation of the clathrin coat and dependent on IP3-mediated homotypic endosomal fusion, These findings confirm the hypothesis that binding and internalization of DEN by hepatocytes are mediated primarily by IIS containing proteoglycans and suggest that flaviviruses traffic the major clathrin-dependent endocytic pathway during infection.