Productive Entry of Foot-and-Mouth Disease Virus via Macropinocytosis Independent of Phosphatidylinositol 3-Kinase.
Productive Entry of Foot-and-Mouth Disease Virus via Macropinocytosis Independent of Phosphatidylinositol 3-Kinase.
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DOI：
10.1038/srep19294
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发表时间：
2016-01-13
影响因子：
4.6
通讯作者：
Liu XT
中科院分区：
文献类型：
--
作者：
Han SC;Guo HC;Sun SQ;Jin Y;Wei YQ;Feng X;Yao XP;Cao SZ;Xiang Liu D;Liu XT
病毒进入是治疗干预的一个有吸引力的目标。在这里，我们结合使用电子显微镜、免疫荧光测定、siRNA 干扰、特异性药理抑制剂和显性失活突变，证明口蹄疫病毒 (FMDV) 的进入引发了大量的质膜波纹。我们还发现，FMDV 的内化诱导了液相摄取的强劲增加，并且病毒粒子内化在与相摄取标记物葡聚糖共定位的巨胞饮体中。在此阶段，Rac1-Pak1信号通路被激活。特异性抑制肌动蛋白、Na+/H+交换体、受体酪氨酸激酶、Rac1、Pak1、肌球蛋白II和蛋白激酶C后，FMDV的进入和感染明显减少。然而，抑制磷脂酰肌醇3激酶（PI3K）并没有减少FMDV的内化，反而在一定程度上增加了病毒的进入和感染，这意味着FMDV的进入不需要PI3K活性。结果表明，FMDV 的内化表现出巨胞饮作用的主要特征。此外，FMDV 的细胞内运输涉及 EEA1/Rab5 阳性囊泡。本研究证明巨胞饮作用是除网格蛋白介导途径之外的另一种内吞途径。这些发现极大地扩展了我们对口蹄疫病毒进入细胞的分子机制的理解，并为其他小核糖核酸病毒的进入机制提供了潜在的见解。
Virus entry is an attractive target for therapeutic intervention. Here, using a combination of electron microscopy, immunofluorescence assay, siRNA interference, specific pharmacological inhibitors, and dominant negative mutation, we demonstrated that the entry of foot-and-mouth disease virus (FMDV) triggered a substantial amount of plasma membrane ruffling. We also found that the internalization of FMDV induced a robust increase in fluid-phase uptake, and virions internalized within macropinosomes colocalized with phase uptake marker dextran. During this stage, the Rac1-Pak1 signaling pathway was activated. After specific inhibition on actin, Na+/H+ exchanger, receptor tyrosine kinase, Rac1, Pak1, myosin II, and protein kinase C, the entry and infection of FMDV significantly decreased. However, inhibition of phosphatidylinositol 3-kinase (PI3K) did not reduce FMDV internalization but increased the viral entry and infection to a certain extent, implying that FMDV entry did not require PI3K activity. Results showed that internalization of FMDV exhibited the main hallmarks of macropinocytosis. Moreover, intracellular trafficking of FMDV involves EEA1/Rab5-positive vesicles. The present study demonstrated macropinocytosis as another endocytic pathway apart from the clathrin-mediated pathway. The findings greatly expand our understanding of the molecular mechanisms of FMDV entry into cells, as well as provide potential insights into the entry mechanisms of other picornaviruses.