Wu Beibei, Ramaiah Arunachalam, Garcia Gustavo, Gwack Yousang, Arumugaswami Vaithilingaraja, Srikanth Sonal
Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
bioRxiv. 2021 May 4:2021.05.04.442548. doi: 10.1101/2021.05.04.442548.
ORAI1 and STIM1 are the critical mediators of store-operated Ca entry by acting as the pore subunit and an endoplasmic reticulum-resident signaling molecule, respectively. In addition to Ca signaling, STIM1 is also involved in regulation of a cytosolic nucleic acid sensing pathway. Using and knockout cells, we examined their contribution to the host response to SARS-CoV-2 infection. knockout cells showed strong resistance to SARS-CoV-2 infection due to enhanced type I interferon response. On the contrary, knockout cells showed high susceptibility to SARS-CoV-2 infection as judged by increased expression of viral proteins and a high viral load. Mechanistically, knockout cells showed reduced homeostatic cytoplasmic Ca concentration and severe impairment in tonic interferon signaling. Transcriptome analysis showed downregulation of multiple cellular defense mechanisms, including antiviral signaling pathways in ORAI1 knockout cells, which are likely due to reduced expression of the Ca -dependent transcription factors of the activator protein 1 (AP-1) family and . Our results identify a novel role of ORAI1-mediated Ca signaling in regulating the baseline type I interferon level, which is a determinant of host resistance to SARS-CoV-2 infection.
ORAI1和STIM1分别作为孔道亚基和内质网驻留信号分子，是储存式钙内流的关键介质。除了钙信号传导外，STIM1还参与细胞溶质核酸传感途径的调节。利用基因敲除细胞，我们研究了它们对宿主对SARS-CoV-2感染反应的贡献。基因敲除细胞由于I型干扰素反应增强而对SARS-CoV-2感染表现出强烈抗性。相反，基因敲除细胞根据病毒蛋白表达增加和高病毒载量判断，对SARS-CoV-2感染表现出高易感性。从机制上讲，基因敲除细胞显示出稳态细胞质钙浓度降低以及强直性干扰素信号传导严重受损。转录组分析显示多种细胞防御机制下调，包括ORAI1基因敲除细胞中的抗病毒信号通路，这可能是由于激活蛋白1（AP-1）家族和 的钙依赖性转录因子表达降低所致。我们的结果确定了ORAI1介导的钙信号传导在调节基线I型干扰素水平中的新作用，而基线I型干扰素水平是宿主对SARS-CoV-2感染抗性的决定因素。
