Figure 6GSDMD-/- THP-1 cells rescued with wild-type or linker substituted GSDMD were transfected with plasmids encoding nucleocapsid or control vector and then stimulated with 10 μM nigericin for 30 min following pretreatment with 1 μg/ml LPS for 3 h. Cells were immunoblotted with antibodies against the indicated proteins (A) GSDMD-/- THP-1 cells rescued with wild-type or linker substituted GSDMD were transfected with plasmids encoding nucleocapsid or control vector and then stimulated with 10 μM nigericin for 30 min following pretreatment with 1 μg/ml LPS for 3 h. supernatants were subjected to an ELISA assay to determine IL-1β levels (B). Otherwise, cell viability in cell pellets was examined using a cell viability assay through checking ATP levels inside cells (C). Student's t-test was used and data were shown as means±SD of three technical replicates. *, P<0.05; **, P<0.01; ***, P<0.001; NS, non-significant. Results were repeated for three times with similar results. GSDMD-/- THP-1 cells rescued with wild-type or linker substituted GSDMD were transfected with plasmids encoding nucleocapsid or control vector and then stimulated with 10 μM nigericin for 30 min following pretreatment with 1 μg/ml LPS for 3 h. Cells were stained with propidium iodide (PI) and the percentage of PI positive cells was calculated (D). Student's t-test was used and data were shown as means±SD of three technical replicates. *, P<0.05; **, P<0.01; ***, P<0.001; NS, non-significant. Results were repeated for three times with similar results. (E, F) GSDMD-/- THP-1 cells rescued with wild-type or linker substituted GSDMD were infected with SARS-CoV-2 at an MOI of 1 for 1h, followed by washing away extracellular viruses and further culture for 3 h. Otherwise, cells were stimulated with 10 μM nigericin for 30 min following pretreatment with 1 μg/ml LPS for 3 h. Supernatants were subjected to an ELISA assay to determine IL-1β levels (E). Otherwise, cell viability in cell pellets was examined using a cell viability assay through checking ATP levels inside cells (F). For E, F, Student's t-test was used and data were shown as means±SD of three technical replicates. **, P<0.01; ***, P<0.001; NS, non-significant. Results were repeated for three times with similar results. (G) Sorted CD14+ monocytes from donors were infected with SARS-CoV-2 at an MOI of 1 for 1h, followed by washing away extracellular viruses and further culture for 3 h. Cells were immunoblotted with antibodies against the indicated proteins. CD14+ monocytes from healthy donors were treated with 10 μM nigericin for 30 min following pretreatment with 1 μg/ml LPS for 3 h and served as a positive control. Data information: experiments were repeated for three time with similar results. (H) Donor monocytes were infected with SARS-CoV-2 at an MOI of 1 for 1h, followed by washing away extracellular viruses and further culture for 3 h. Supernatants were collected and subjected to a proteome profiling using an antibody array. Intensities for each cytokine were normalized individually and shown together as scores for both dot size and color. LPS and nigericin treated healthy donor monocytes served as a positive control. n=6 for each group.