TNF and COVID-19: In order to confirm the cellular functions of SARS-CoV-2 N protein in NF-κB pathway, we generated SARS-CoV-2 N-stably-expressed Calu3 and Huh7 cells, and found that N protein markedly enhanced the phosphorylation level of IKK, p65, and IκBα, but not the phosphorylation of p38, ERK, and JNK after SARS-CoV-2 infection or poly(I:C) and TNFα treatment (Fig. 1g and Supplementary Fig. S3a).