DC-SIGN and L-SIGN Are Attachment Factors That Promote Infection of Target Cells by Human Metapneumovirus in the Presence or Absence of Cellular Glycosaminoglycans
DC-SIGN and L-SIGN Are Attachment Factors That Promote Infection of Target Cells by Human Metapneumovirus in the Presence or Absence of Cellular Glycosaminoglycans
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DOI：
10.1128/jvi.00537-16
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发表时间：
2016-09-01
影响因子：
5.4
通讯作者：
Reading, Patrick C.
中科院分区：
文献类型：
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作者：
Gillespie, Leah;Gerstenberg, Kathleen;Reading, Patrick C.
糖胺多聚糖(GAG)是人类偏肺病毒(HMPV)的黏附因子，在细胞表面聚集病毒粒子，促进与其他受体的相互作用，从而促进病毒的进入和感染。越来越多的证据表明，多个受体可能表现出促进HMPV侵染性进入宿主细胞的能力；然而，由于细胞表面GaG的广泛表达，确定HMPV附着和进入的特异性跨膜受体是复杂的。PgsA745中国仓鼠卵巢(CHO)细胞缺乏细胞表面GAG的表达，对HMPV感染具有抵抗力。在这里，我们证明了依赖于钙离子的C型凝集素受体(CLR)、DC-SIGN(CD209L)或L-SIGN(CD209L)的表达使pgsA745细胞对HMPV感染具有容许性。与亲本CHO细胞感染不同，表达DC-SIGN或L-SIGN的pgsA745细胞感染HMPV是动力依赖性的，甘露聚糖对其有抑制作用，但不受细菌肝素酶的抑制。表达DC-SIGN/L-SIGN的亲本CHO细胞对动力蛋白依赖的HMPV感染的敏感性也增强，证实了CLRs在有或无GAGS的情况下都能促进HMPV的感染。对表达野生型和内吞缺陷DC-SIGN/L-SIGN突变体的pgsA745细胞的比较表明，CLRs的内吞功能不是必需的，但可能与HMPV感染Gag缺陷细胞有关。总之，这些研究证实了CLR作为HMPV感染的附着因子和进入受体的作用。此外，他们还定义了一个实验系统，可以用来识别跨膜受体和进入途径，在这些途径中，单个细胞表面受体的表达可以挽救对HMPV感染的通透性。在CHO细胞表面，糖胺多聚糖(GAG)是人类偏肺病毒(HMPV)的主要附着因子，促进动力非依赖性感染。与此一致，GAG缺陷的pgaA745 CHO细胞对HMPV具有抵抗力。然而，DC-SIGN或L-SIGN的表达使pgsA745细胞对HMPV动力依赖性感染具有容许性，尽管DC-SIGN/L-SIGN的内吞功能不是增强感染所必需的，但可能有助于增强感染。这些研究为DC-SIGN/L-SIGN作为HMPV附着的替代附着因子提供了直接证据，在没有GAG的情况下，通过其他未知的受体促进动力蛋白依赖的感染。此外，我们描述了一个独特的实验系统，用于评估假定的HMPV附着和进入受体。
It is well established that glycosaminoglycans (GAGs) function as attachment factors for human metapneumovirus (HMPV), concentrating virions at the cell surface to promote interaction with other receptors for virus entry and infection. There is increasing evidence to suggest that multiple receptors may exhibit the capacity to promote infectious entry of HMPV into host cells; however, definitive identification of specific transmembrane receptors for HMPV attachment and entry is complicated by the widespread expression of cell surface GAGs. pgsA745 Chinese hamster ovary (CHO) cells are deficient in the expression of cell surface GAGs and resistant to HMPV infection. Here, we demonstrate that the expression of the Ca2+-dependent C-type lectin receptor (CLR) DC-SIGN (CD209L) or L-SIGN (CD209L) rendered pgsA745 cells permissive to HMPV infection. Unlike infection of parental CHO cells, HMPV infection of pgsA745 cells expressing DC-SIGN or L-SIGN was dynamin dependent and inhibited by mannan but not by pretreatment with bacterial heparinase. Parental CHO cells expressing DC-SIGN/L-SIGN also showed enhanced susceptibility to dynamin-dependent HMPV infection, confirming that CLRs can promote HMPV infection in the presence or absence of GAGs. Comparison of pgsA745 cells expressing wild-type and endocytosis-defective mutants of DC-SIGN/L-SIGN indicated that the endocytic function of CLRs was not essential but could contribute to HMPV infection of GAG-deficient cells. Together, these studies confirm a role for CLRs as attachment factors and entry receptors for HMPV infection. Moreover, they define an experimental system that can be exploited to identify transmembrane receptors and entry pathways where permissivity to HMPV infection can be rescued following the expression of a single cell surface receptor.IMPORTANCEOn the surface of CHO cells, glycosaminoglycans (GAGs) function as the major attachment factor for human metapneumoviruses (HMPV), promoting dynamin-independent infection. Consistent with this, GAG-deficient pgaA745 CHO cells are resistant to HMPV. However, expression of DC-SIGN or L-SIGN rendered pgsA745 cells permissive to dynamin-dependent infection by HMPV, although the endocytic function of DC-SIGN/L-SIGN was not essential for, but could contribute to, enhanced infection. These studies provide direct evidence implicating DC-SIGN/L-SIGN as an alternate attachment factor for HMPV attachment, promoting dynamin-dependent infection via other unknown receptors in the absence of GAGs. Moreover, we describe a unique experimental system for the assessment of putative attachment and entry receptors for HMPV.