Influenza A virus entry into cells lacking sialylated N-glycans
Influenza A virus entry into cells lacking sialylated N-glycans
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DOI：
10.1073/pnas.1200987109
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发表时间：
2012-05-08
影响因子：
11.1
通讯作者：
de Haan, Cornelis A. M.
中科院分区：
文献类型：
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作者：
de Vries, Erik;de Vries, Robert P.;de Haan, Cornelis A. M.
甲型流感病毒（IAV）在其血凝素（HA）附着于表面暴露的唾液酸后进入宿主细胞。据报道，唾液化的n -链聚糖对IAV进入至关重要[Chu VC， Whittaker GR (2004) Proc Natl Acad Sci USA 102: 18153-18158]，从而暗示了IAV进入需要蛋白质受体。在这里，我们使用不同的n -乙酰氨基葡萄糖转移酶1 （GnT1）缺陷细胞，表明n -连接的唾液苷可以介导，但不是IAV进入所必需的。进入gnt1缺陷细胞完全依赖于唾液酸。尽管巨红细胞的进入似乎受到唾液化n-聚糖缺失的影响，但动力蛋白依赖的进入根本不受影响。然而，血清的存在减少了HA与gnt1缺陷细胞的结合和随后的IAV进入，这可以通过反向转染gnt1编码质粒来逆转。血清对病毒受体破坏酶神经氨酸酶（NA）的抑制作用显著增强。我们的研究结果表明，可溶性血清因子上的诱饵受体与细胞表面受体竞争，在细胞表面没有唾液化n -聚糖的情况下与HA结合。这种竞争尤其受到NA抑制剂的额外存在的干扰，导致IAV进入的强烈减少。我们的研究结果表明，HA和NA之间的平衡不仅对病毒粒子的释放很重要，而且对进入细胞也很重要。
Influenza A virus (IAV) enters host cells after attachment of its hemagglutinin (HA) to surface-exposed sialic acid. Sialylated N-linked glycans have been reported to be essential for IAV entry [Chu VC, Whittaker GR (2004) Proc Natl Acad Sci USA 102: 18153-18158], thereby implicating the requirement for proteinaceous receptors in IAV entry. Here we show, using different N-acetylglucosaminyl transferase 1 (GnT1)-deficient cells, that N-linked sialosides can mediate, but are not required for, entry of IAV. Entry into GnT1-deficient cells was fully dependent on sialic acid. Although macropinocytic entry appeared to be affected by the absence of sialylated N-glycans, dynamin-dependent entry was not affected at all. However, binding of HA to GnT1-deficient cells and subsequent entry of IAV were reduced by the presence of serum, which could be reversed by back-transfection of a GnT1-encoding plasmid. The inhibitory effect of serum was significantly increased by inhibition of the viral receptor-destroying enzyme neuraminidase (NA). Our results indicate that decoy receptors on soluble serum factors compete with cell surface receptors for binding to HA in the absence of sialylated N-glycans at the cell surface. This competition is particularly disturbed by the additional presence of NA inhibitors, resulting in strongly reduced IAV entry. Our results indicate that the balance between HA and NA is important not only for virion release, but also for entry into cells.