Figure 4

NDV induction of IL-1β expression through NLRP3/caspase-1.A NLRP3 expression in the lungs, glandular stomach, and bursa of Fabricius of chickens. B NLRP3 expression in DF1 cells. C Activation of caspase-1 in the lungs, glandular stomach, and bursa of Fabricius of chickens. D Activation of caspase-1 in DF1 cells. DF1 cells and the organs of chickens at 3 dpi were collected for detection of caspase-1 activity using a caspase-1 activity assay kit. E NLRP3 and IL-1β expression after overexpression of NLRP3 and infection with GM NDV. F NLRP3 and IL-1β expression after transfection with i-NLRP3 and infection with GM NDV. G The viability of DF1 cells that were transfected with Si-NC or Si-NLRP3 was measured by CCK-8 cell proliferation and cytotoxicity assay kits. DF1 cells were transfected with an NLRP3 overexpression plasmid or Si-NLRP3 for 24 h and then infected with GM NDV at a MOI of 1 for 24 h. Cells and cell culture supernatant were collected, and the expression of NLRP3 and IL-1β was assessed by Western blot and ELISA. H Caspase-1 activation after incubation with the caspase-1-specific inhibitor Ac-YVAD-CHO. I IL-1β expression after incubation with the caspase-1-specific inhibitor Ac-YVAD-CHO. J The viability of DF1 cells that were treated with Ac-YVAD-CHO was measured by CCK-8 cell proliferation and cytotoxicity assay kits. DF1 cells were incubated with Ac-YVAD-CHO (20 μM) for 1 h and then infected with GM NDV at a MOI of 1 for 24 h. Cells and cell culture supernatant were collected at 24 hpi, and caspase-1 activity and IL-1β expression were assessed. *P < 0.05, **P < 0.01, and ***P < 0.001 between the experimental and control groups.