Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, Maryland, USA.
United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, USA.
J Virol. 2015 Jan;89(1):844-56. doi: 10.1128/JVI.02697-14. Epub 2014 Oct 29.
Simian hemorrhagic fever virus (SHFV) causes a severe and almost uniformly fatal viral hemorrhagic fever in Asian macaques but is thought to be nonpathogenic for humans. To date, the SHFV life cycle is almost completely uncharacterized on the molecular level. Here, we describe the first steps of the SHFV life cycle. Our experiments indicate that SHFV enters target cells by low-pH-dependent endocytosis. Dynamin inhibitors, chlorpromazine, methyl-β-cyclodextrin, chloroquine, and concanamycin A dramatically reduced SHFV entry efficiency, whereas the macropinocytosis inhibitors EIPA, blebbistatin, and wortmannin and the caveolin-mediated endocytosis inhibitors nystatin and filipin III had no effect. Furthermore, overexpression and knockout study and electron microscopy results indicate that SHFV entry occurs by a dynamin-dependent clathrin-mediated endocytosis-like pathway. Experiments utilizing latrunculin B, cytochalasin B, and cytochalasin D indicate that SHFV does not hijack the actin polymerization pathway. Treatment of target cells with proteases (proteinase K, papain, α-chymotrypsin, and trypsin) abrogated entry, indicating that the SHFV cell surface receptor is a protein. Phospholipases A2 and D had no effect on SHFV entry. Finally, treatment of cells with antibodies targeting CD163, a cell surface molecule identified as an entry factor for the SHFV-related porcine reproductive and respiratory syndrome virus, diminished SHFV replication, identifying CD163 as an important SHFV entry component.
Simian hemorrhagic fever virus (SHFV) causes highly lethal disease in Asian macaques resembling human illness caused by Ebola or Lassa virus. However, little is known about SHFV's ecology and molecular biology and the mechanism by which it causes disease. The results of this study shed light on how SHFV enters its target cells. Using electron microscopy and inhibitors for various cellular pathways, we demonstrate that SHFV invades cells by low-pH-dependent, actin-independent endocytosis, likely with the help of a cellular surface protein.
猿猴出血热病毒 (SHFV) 在亚洲猕猴中引起严重且几乎普遍致命的病毒性出血热，但据认为对人类无致病性。迄今为止，SHFV 的生命周期在分子水平上几乎完全没有特征。在这里，我们描述了 SHFV 生命周期的最初步骤。我们的实验表明，SHFV 通过依赖低 pH 值的内吞作用进入靶细胞。使用德拉马尼抑制剂、氯丙嗪、甲基-β-环糊精、氯喹和康那霉素 A 可显著降低 SHFV 进入效率，而巨胞饮抑制剂 EIPA、blebbistatin 和 wortmannin 以及质膜窖介导的内吞作用抑制剂 nystatin 和 filipin III 则没有效果。此外，过表达和敲除研究以及电子显微镜结果表明，SHFV 通过依赖于网格蛋白的内吞作用样途径进入细胞。利用 latrunculin B、细胞松弛素 B 和细胞松弛素 D 的实验表明，SHFV 不会劫持肌动蛋白聚合途径。用蛋白酶（蛋白水解酶 K、木瓜蛋白酶、α-糜蛋白酶和胰蛋白酶）处理靶细胞可破坏进入，表明 SHFV 细胞表面受体是一种蛋白质。磷脂酶 A2 和 D 对 SHFV 进入没有影响。最后，用针对 CD163 的抗体处理细胞，CD163 是一种已鉴定为与 SHFV 相关的猪繁殖与呼吸综合征病毒进入因子的细胞表面分子，可降低 SHFV 的复制，表明 CD163 是 SHFV 进入的重要组成部分。
猿猴出血热病毒 (SHFV) 在亚洲猕猴中引起类似于埃博拉或拉萨病毒引起的人类疾病的高度致命疾病。然而，人们对 SHFV 的生态学和分子生物学以及它引起疾病的机制知之甚少。本研究结果阐明了 SHFV 进入靶细胞的方式。通过电子显微镜和各种细胞途径的抑制剂，我们证明 SHFV 通过依赖低 pH 值的、肌动蛋白非依赖性内吞作用进入细胞，可能需要细胞表面蛋白的帮助。
