Fig. 4.

SARS-CoV-2 N protein-triggered inflammation via the activation of SGK1 in RECs. a The phosphorylation level of SGK1 after N protein (50 μg/ml) stimulation in BEAS-2B cells, with the gray value analysis (n = 3). b The effect of EMD638683 (50 μM) on the mRNA expressions of pro-inflammatory cytokines in N protein (50 μg/ml)-stimulated BEAS-2B cells (n = 3). c The mRNA expressions of cytokines after N protein (50 μg/ml) stimulation in the empty vector control or SGK1 KO BEAS-2B cells (n = 3). d The phosphorylation level of SGK1 in lungs of N protein (0.25 mg/kg)-stimulated mice, with the gray value analysis (n = 3). e Fluorescence labeling of phosphorylated SGK1 (green) and N protein (red) in lung slices of hACE2-transduced mice infected with SARS-CoV-2 (1 × 10⁵ PFU). Scale bars, 10 μm. f The effect of EMD638683 (10 mg/kg) on the mRNA expressions of cytokines in N protein (0.25 mg/kg)-stimulated mice (n = 3). g The effect of EMD638683 (10 mg/kg) on the phosphorylation level of IκB and NF-κB p65 subunit in N protein (0.25 mg/kg)-stimulated mice, with the gray value analysis (n = 3). h H&E staining of lung slices from N protein (0.25 mg/kg)-stimulated mice with or without treatment with EMD638683 (10 mg/kg). Scale bars, 50 μm and 25 μm. Data were shown as mean ± SD, ^*P < 0.05, ^**P < 0.01, ^***P < 0.001 compared with the control group or indicated by lines, n.s. P > 0.05