FIG 8.

NLRP3 inflammasome activation requires three distinct upstream signals: K⁺ efflux, lysosomal degradation, and ROS production. Cells stimulated with or without Chlamydia pneumoniae in the presence of absence of CNTs were incubated with either 70 mM KCl, 10 μM CA-074 Me (a cathepsin B inhibitor), or ROS inhibitors (5 mM NAC or 10 μM DPI) for 24 h, and then IL-1β secretion from macrophages was detected. Treatment with KCl (A), CA-074 Me (B), or DPI (C), but not NAC, blocked IL-1β secretion. Results are representative of three independent experiments. Cpn, C. pneumoniae; CNT, carbon nanotube; IL-1β, interleukin-1β; LPS, lipopolysaccharide; DMSO, dimethyl sulfoxide; ROS, reactive oxygen species.