Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
J Virol. 2013 Aug;87(16):8884-95. doi: 10.1128/JVI.03415-12. Epub 2013 Jun 5.
Enteroviruses invade their hosts by crossing the intestinal epithelium. We have examined the mechanism by which echovirus 1 (EV1) enters polarized intestinal epithelial cells (Caco-2). Virus binds to VLA-2 on the apical cell surface and moves rapidly to early endosomes. Using inhibitory drugs, dominant negative mutants, and small interfering RNAs (siRNAs) to block specific endocytic pathways, we found that virus entry requires dynamin GTPase and membrane cholesterol but is independent of both clathrin- and caveolin-mediated endocytosis. Instead, infection requires factors commonly associated with macropinocytosis, including amiloride-sensitive Na(+)/H(+) exchange, protein kinase C, and C-terminal-binding protein-1 (CtBP1); furthermore, EV1 accumulates rapidly in intracellular vesicles with dextran, a fluid-phase marker. These results suggest a role for macropinocytosis in the process by which EV1 enters polarized cells to initiate infection.
肠道病毒通过穿过肠上皮细胞来感染宿主。我们研究了肠道病毒 1（EV1）进入极化肠上皮细胞（Caco-2）的机制。病毒与顶端细胞表面的 VLA-2 结合，并迅速移动到早期内体。使用抑制性药物、显性负突变体和小干扰 RNA（siRNA）阻断特定的内吞途径，我们发现病毒进入需要动力蛋白 GTP 酶和膜胆固醇，但不依赖于网格蛋白和胞饮作用。相反，感染需要与胞吞作用相关的常见因子，包括阿米洛利敏感的 Na(+)/H(+)交换、蛋白激酶 C 和 C 端结合蛋白 1（CtBP1）；此外，EV1 迅速积累在含有葡聚糖的细胞内囊泡中，葡聚糖是一种液相标记物。这些结果表明，巨胞饮作用在 EV1 进入极化细胞以启动感染的过程中起作用。
