Schilling Erik, Wald Maria Elisabeth, Schulz Juliane, Werner Lina Emilia, Claus Claudia
Institute of Clinical Immunology, Medical Faculty, Leipzig University, Johannisallee 30, 04103 Leipzig, Germany.
Institute of Virology, Faculty of Veterinary Medicine, Leipzig University, An den Tierkliniken 29, 04103 Leipzig, Germany.
Pathogens. 2022 May 3;11(5):537. doi: 10.3390/pathogens11050537.
Interferons (IFNs) are an essential part of innate immunity and contribute to adaptive immune responses. Here, we employed a loss-of-function analysis with human A549 respiratory epithelial cells with a knockout (KO) of the type I IFN receptor (IFNAR KO), either solely or together with the receptor of type III IFN (IFNAR/IFNLR1 KO). The course of rubella virus (RuV) infection on the IFNAR KO A549 cells was comparable to the control A549. However, on the IFNAR/IFNLR1 KO A549 cells, both genome replication and the synthesis of viral proteins were significantly enhanced. The generation of IFN β during RuV infection was influenced by type III IFN signaling. In contrast to IFNAR KO A549, extracellular IFN β was not detected on IFNAR/IFNLR1 KO A549. The bioenergetic profile of RuV-infected IFNAR/IFNLR1 KO A549 cells generated by extracellular flux analysis revealed a significant increase in glycolysis, whereas mitochondrial respiration was comparable between all three cell types. Moreover, the application of the glucose analogue 2-deoxy-D-glucose (2-DG) significantly increased viral protein synthesis in control A549 cells, while no effect was noted on IFNAR/IFNLR KO A549. In conclusion, we identified a positive signaling circuit of type III IFN signaling on the generation of IFN β during RuV infection and an IFN signaling-dependent contribution of glycolysis to RuV infection. This study on epithelial A549 cells emphasizes the interaction between glycolysis and antiviral IFN signaling and notably, the antiviral activity of type III IFNs against RuV infection, especially in the absence of both type I and III IFN signaling, the RuV replication cycle was enhanced.
干扰素（IFNs）是固有免疫的重要组成部分，并有助于适应性免疫反应。在此，我们对人A549呼吸道上皮细胞进行功能丧失分析，该细胞敲除了I型干扰素受体（IFNAR敲除），单独敲除或与III型干扰素受体一起敲除（IFNAR/IFNLR1敲除）。风疹病毒（RuV）在IFNAR敲除的A549细胞上的感染过程与对照A549细胞相当。然而，在IFNAR/IFNLR1敲除的A549细胞上，基因组复制和病毒蛋白合成均显著增强。RuV感染期间IFNβ的产生受III型干扰素信号传导的影响。与IFNAR敲除的A549细胞不同，在IFNAR/IFNLR1敲除的A549细胞上未检测到细胞外IFNβ。通过细胞外流量分析产生的RuV感染的IFNAR/IFNLR1敲除的A549细胞的生物能量谱显示糖酵解显著增加，而所有三种细胞类型之间的线粒体呼吸相当。此外，葡萄糖类似物2-脱氧-D-葡萄糖（2-DG）的应用显著增加了对照A549细胞中的病毒蛋白合成，而对IFNAR/IFNLR敲除的A549细胞没有影响。总之，我们确定了III型干扰素信号传导在RuV感染期间对IFNβ产生的正向信号回路以及糖酵解对RuV感染的IFN信号传导依赖性贡献。这项对上皮A549细胞的研究强调了糖酵解与抗病毒IFN信号传导之间的相互作用，值得注意的是，III型干扰素对RuV感染的抗病毒活性，特别是在缺乏I型和III型干扰素信号的情况下，RuV复制周期增强。
