Fig. 5

Inhibition of cathepsin B, ROS, K+ and caspase-1 impairs NLRP3 inflammasome activation and IL-1β expression in T. pallidum-infected macrophages. a, mRNA level of NLRP3. b, mRNA level of caspase-1. c, mRNA level of IL-1β. d, Protein level of IL-1β determined by ELISA. e and f, Protein levels of NLRP3, active caspase-1, and IL-1β determined by western blotting analysis. The values represent the means±SDs of triplicate trials and are representative of three independent experiments. The western blotting results are representative of three independent experiments. Student’s t-test was applied to compare the treatment groups with the control group. NS, non-significant difference, **P < 0.01; *** P < 0.001. NAC, N-acetylcysteine (an ROS inhibitor); CA074-ME, a cathepsin B inhibitor; KCl, a potassium channel inhibitor; Z-VAD-FMK, N-benzyloxycarbonyl-Val-Ala-Asp (O-methyl)-fluoromethyl ketone (a caspase-1 inhibitor)