Figure 4

Hydroxyapatite particle-induced IL-1β production is NLRP3 dependent. (A) BMDCs (0.625 × 10⁶ cells · ml⁻¹) from C57BL/6 or NLRP3^−/− mice were stimulated with HA particles at concentrations ranging from 0.2 mg · ml⁻¹ to 1 mg · ml⁻¹ after priming with LPS (1 ng · ml⁻¹) for 3 h. Supernatants were collected after 24 hours and IL-1β levels were measured by ELISA. Data are shown as mean ± SD for triplicate samples (vs WT ***p < 0.001; NS: non-significant). Results are representative of three independent experiments. (B) BMDCs (0.625 × 10⁶ cells · ml⁻¹) from female C57BL/6 mice were primed with LPS (1 ng · ml⁻¹) for 3 h before stimulating with 0.8 mg · ml⁻¹ of HA particles; cells were incubated with the lysosome acidification inhibitor bafilomycin A (62.5–250 nM), the cathepsin B inhibitor CA-074-Me (2.5–10 µM) and with the ROS inhibitor DPI (5–20 µM) 1 h before particulate addition. Supernatants were collected after 24 hours and IL-1β levels were measured by ELISA. Data are shown as mean ± SD for triplicate samples. Results are representative of three independent experiments (vs no inhibitor ***p < 0.001).