Fig. 1: SARS-CoV-2 N protein induces inflammatory responses.

Transcriptional level of indicated gene in macrophage (a) and dendritic cells (b) infected with SARS-CoV-2 (GSE155106, RNA-Seq data from GEO database) were analyzed and the values were showed in logarithmic form. c HEK293T cells were transfected with plasmids encoding N, M, E, 3a, 6, 7a, 8, and 10 proteins for 24 h. The indicated proteins in cell extract were analyzed by WB. d HEK293T cells were co-transfected with plasmids encoding NLRP3, ASC, pro-Caspase-1, or pro-IL-1β, and transfected with plasmids encoding N, M, E, 3a, 6, 7a, 8, and 10 for 48 h. Supernatants were analyzed by ELISA for IL-1β. e PMA-differentiated THP-1 macrophages were transfected with plasmids encoding N, M, E, 3a, 6, 7a, 8, and 10 proteins for 48 h, and then stimulated with 2 μM Nigericin or DMSO for 2 h. IL-1β in cell supernatants was measured by ELISA. f, g THP-1 cells were stably infected with Lentivirus-CT or Lentivirus-N, differentiated into macrophages. Lentivirus-N macrophages were then treated with MCC950 (0.01 μM) for 1 h. Cell lysates were analyzed by immunoblotting (f). The indicated gene mRNA was quantified by qRT-PCR (g). h, i C57BL/6 genetic background mice were tail vein-injected with 300 μl containing 5 × 10¹¹ vg of AAV-Lung-EGFP (n = 8) or AAV-Lung-N (n = 16); after 2 weeks, they were treated with MCC950 (50 mg/kg) or Ac-YVAD-cmk (8 mg/kg) by intraperitoneal injection for AAV-Lung-N (n = 8) mice; after 3 weeks, two mice for each group were killed and the lungs were collected. The indicated proteins were analyzed by WB (h). The indicated gene mRNAs were quantified by qRT-PCR (i). Mock means healthy donors (a, b), untreated cells (e), and injection of the same dose of PBS (i). Control means transfected with empty plasmids (c, d). Lipo means transfection with reagents Lipo2000 (e). Data are representative of three independent experiments and one representative is shown. Error bars indicate SD of technical triplicates. Values are mean ± SEM. *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001, two-tailed Student’s t-test. Source data are provided as a Source Data file.