Institute of Anatomy and Vascular Biology, Westfälische Wilhelms University Muenster, Vesaliusweg, Germany.
J Infect Dis. 2011 Nov;204 Suppl 3(Suppl 3):S957-67. doi: 10.1093/infdis/jir326.
Virus entry into host cells is the first step of infection and a crucial determinant of pathogenicity. Here we show that Ebola virus-like particles (EBOV-VLPs) composed of the glycoprotein GP(1,2) and the matrix protein VP40 use macropinocytosis and clathrin-mediated endocytosis to enter cells. EBOV-VLPs applied to host cells induced actin-driven ruffling and enhanced FITC-dextran uptake, which indicated macropinocytosis as the main entry mechanism. This was further supported by inhibition of entry through inhibitors of actin polymerization (latrunculin A), Na(+)/H(+)-exchanger (EIPA), and PI3-kinase (wortmannin). A fraction of EBOV-VLPs, however, colocalized with clathrin heavy chain (CHC), and VLP uptake was reduced by CHC small interfering RNA transfection and expression of the dominant negative dynamin II-K44A mutant. In contrast, we found no evidence that EBOV-VLPs enter cells via caveolae. This work identifies macropinocytosis as the major, and clathrin-dependent endocytosis as an alternative, entry route for EBOV particles. Therefore, EBOV seems to utilize different entry pathways depending on both cell type and virus particle size.
病毒进入宿主细胞是感染的第一步，也是致病性的关键决定因素。在这里，我们表明由糖蛋白 GP(1,2) 和基质蛋白 VP40 组成的埃博拉病毒样颗粒 (EBOV-VLPs) 通过巨胞饮作用和网格蛋白介导的内吞作用进入细胞。应用于宿主细胞的 EBOV-VLPs 诱导肌动蛋白驱动的皱襞形成并增强 FITC-葡聚糖摄取，这表明巨胞饮作用是主要的进入机制。这进一步得到了肌动蛋白聚合抑制剂（拉曲库铵 A）、Na(+)/H(+) 交换抑制剂 (EIPA) 和 PI3-激酶抑制剂 (wortmannin) 抑制进入的支持。然而，一部分 EBOV-VLPs 与网格蛋白重链 (CHC) 共定位，并且 CHC 小干扰 RNA 转染和显性负性 dynamin II-K44A 突变体的表达降低了 VLP 的摄取。相比之下，我们没有发现 EBOV-VLPs 通过 caveolae 进入细胞的证据。这项工作确定巨胞饮作用是 EBOV 颗粒的主要进入途径，网格蛋白依赖性内吞作用是替代进入途径。因此，EBOV 似乎根据细胞类型和病毒颗粒大小利用不同的进入途径。
