Mok Lawrence, Wynne James W, Tachedjian Mary, Shiell Brian, Ford Kris, Matthews David A, Bacic Antony, Michalski Wojtek P
CSIRO, Australian Animal Health Laboratory, East Geelong, VIC, Australia.
ARC Centre of Excellence in Plant Cell Walls School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia.
BMC Genomics. 2017 Aug 14;18(1):615. doi: 10.1186/s12864-017-3994-x.
Nelson Bay orthoreovirus (NBV) is a fusogenic bat borne virus with an unknown zoonotic potential. Previous studies have shown that NBV can infect and replicate in a wide variety of cell types derived from their natural host (bat), as well as from human, mouse and monkey. Within permissive cells, NBV induced significant cytopathic effects characterised by cell-cell fusion and syncytia formation. To understand the molecular events that underpin NBV infection we examined the host transcriptome and proteome response of two cell types, derived from bat (PaKiT03) and mouse (L929), to characterise differential cellular susceptibility to NBV.
Despite significant differences in NBV replication and cytopathic effects in the L929 and PaKiT03 cells, the host response was remarkably similar in these cells. At both the transcriptome and proteome level, the host response was dominated by IFN production and signalling pathways. The majority of proteins up-regulated in L929 and PaKiT03 cells were also up-regulated at the mRNA (gene) level, and included many important IFN stimulated genes. Further functional experimentation demonstrated that stimulating IFN signalling prior to infection, significantly reduced NBV replication in PaKiT03 cells. Moreover, inhibiting IFN signalling (through specific siRNAs) increased NBV replication in L929 cells. In line with the significant cytopathic effects seen in PaKiT03 cells, we also observed a down-regulation of genes involved in cell-cell junctions, which may be related to the fusogenic effects of NBV.
This study provides new multi-dimensional insights into the host response of mammalian cells to NBV infection. We show that IFN activity is capable of reducing NBV replication, although it is unlikely that this is solely responsible for the reduced replication of NBV in L929 cells. The molecular events that underpin the fusogenic cytopathic effects described here will prove valuable for identifying potential therapeutic targets against fusogenic orthoreovirus.
纳尔逊湾正呼肠孤病毒（NBV）是一种具有融合性的蝙蝠传播病毒，其人畜共患病潜力未知。先前的研究表明，NBV能够在源自其自然宿主（蝙蝠）以及人类、小鼠和猴子的多种细胞类型中感染和复制。在允许性细胞内，NBV诱导了以细胞 - 细胞融合和多核巨细胞形成为特征的显著细胞病变效应。为了了解支持NBV感染的分子事件，我们检测了源自蝙蝠（PaKiT03）和小鼠（L929）的两种细胞类型的宿主转录组和蛋白质组反应，以表征对NBV的不同细胞易感性。
尽管NBV在L929和PaKiT03细胞中的复制和细胞病变效应存在显著差异，但这些细胞中的宿主反应非常相似。在转录组和蛋白质组水平上，宿主反应均以干扰素产生和信号通路为主导。在L929和PaKiT03细胞中上调的大多数蛋白质在mRNA（基因）水平上也上调，并且包括许多重要的干扰素刺激基因。进一步的功能实验表明，在感染前刺激干扰素信号通路可显著降低PaKiT03细胞中的NBV复制。此外，抑制干扰素信号通路（通过特异性小干扰RNA）可增加L929细胞中的NBV复制量。与PaKiT03细胞中观察到的显著细胞病变效应一致，我们还观察到参与细胞 - 细胞连接相关基因的下调，这可能与NBV的融合效应有关。
本研究为哺乳动物细胞对NBV感染的宿主反应提供了新的多维度见解。我们表明干扰素活性能够降低NBV复制，尽管这不太可能是L929细胞中NBV复制减少的唯一原因。此处所述的支持融合性细胞病变效应的分子事件对于确定针对融合性正呼肠孤病毒的潜在治疗靶点将具有重要价值。
