The pulmonary stem/progenitor cells, which could be differentiated into downstream cells to repair tissue damage caused by influenza A virus, have also been shown to be the target cells of influenza virus infection. In this study, mouse pulmonary stem/progenitor cells (mPSCs) with capability to differentiate into type I or type II alveolar cells were used as an in vitro cell model to characterize replication and pathogenic effects of influenza viruses in PSCs. First, mPSCs and its immortalized cell line mPSCsOct4+ were shown to be susceptible to PR8, seasonal H1N1, 2009 pandemic H1N1, and H7N9 influenza viruses and can generate infectious virus particles, although with a lower virus titer, which could be attributed by the reduced vRNA replication and nucleoprotein (NP) aggregation in the cytoplasm. Nevertheless, a significant increase of interleukin (IL)-6 and interferon (IFN)-γ at 12 h and IFN-β at 24 h post infection in mPSCs implicates that mPSCs might function as a sensor to modulate immune responses to influenza virus infection. In summary, our results demonstrated mPSCs, as one of the target cells for influenza A viruses, could modulate early proinflammatory responses to influenza virus infection.

中文翻译：

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小鼠肺干/祖细胞中甲型流感病毒感染的特征。

肺干/祖细胞可被分化为下游细胞，以修复由甲型流感病毒引起的组织损伤，也已被证明是流感病毒感染的靶细胞。在这项研究中，具有分化为I型或II型肺泡细胞能力的小鼠肺干/祖细胞（mPSC）被用作体外细胞模型，以表征流感病毒在PSC中的复制和致病作用。首先，mPSC及其永生化细胞系mPSCsOct4 +已显示对PR8，季节性H1N1、2009大流行H1N1和H7N9流感病毒敏感，并且可以产生传染性病毒颗粒，尽管病毒滴度较低，这可能是由于vRNA降低所致细胞质中的复制和核蛋白（NP）聚集。不过，mPSC感染后12小时时白介素（IL）-6和干扰素（IFN）-γ显着增加，而24小时后IFN-β显着增加，这暗示mPSC可能充当调节流感病毒感染免疫反应的传感器。总之，我们的结果表明，mPSCs作为甲型流感病毒的靶细胞之一，可以调节对流感病毒感染的早期促炎反应。