Fig. 2.

p38 MAPK inhibition reduces the expression of pro-inflammatory cytokines.

Calu-3 cells were pre-treated for 1 h with DMSO (control) or the inhibitors PH-797804 and VX-702 before infection with SARS-CoV-2 at MOI 0.01 for 48 h. A) Western blot analysis to determine inhibition of p38 MAPK by the inhibitors PH-797804 and VX-702. Phosphorylation of p38 (p-p38) and the downstream kinase MSK1 (p-MSK1) was determined using phospho-specific antibodies. Quantification of p38 (p-p38/p38) and MSK1 (p-MSK1/MSK1) phosphorylation levels are depicted below the blots. B) Effect of PH-797804 and VX-702 treatment on virus replication. Calu-3 cells were treated as described above. Viral titers are displayed as PFU/ml ± SEM from 3 independent experiments and effect of C) PH-797804 and D) VX-702 treatment on cytokine expression. Calu-3 cells were treated as described above and 48 h p.i. total RNA was isolated and mRNA levels of the indicated cytokines and ISGs were determined using qRT-PCR with gene specific primers. Data are displayed as n-fold induction over non-treated and non-infected cells. Bars represent mean values ± SEM from at least 3 independent replicates. Statistical significance was determined using two-way ANOVA followed by Dunnett's multiple comparison test. E) Chip-based kinase activity profiling of SARS-CoV-2-infected and PH-797804 or VX-702 inhibitor-treated cells. Calu-3 cells were infected with SARS-CoV-2 at 0.1 MOI for 24 h in the presence of DMSO, PH-797804 or VX-702 (5 μM). Serine-threonine kinase activity was evaluated using PamGene technology and differences in kinase activity in infected inhibitor-treated compared to infected and DMSO-treated cells are depicted as median kinase statistic (negative values = lower activity, positive values = higher activity), n = 3.