Antimicrobial Cathelicidin Peptide LL-37 Inhibits the LPS/ATP-Induced Pyroptosis of Macrophages by Dual Mechanism
Figure 1
Effect of LPS and ATP treatment on the pyroptosis of J774 cells.
Macrophage-like J774 cells were primed with 10 ng/ml LPS for 4 h, and then treated with 3 mM ATP for the indicated time periods in the absence or presence of 20 µM Ac-YVAD-CHO, a caspase-1 specific inhibitor. Cells were also incubated with LPS or ATP alone, or without LPS and ATP (Resting). Thereafter, the supernatants were recovered for the assays of IL-1β (A) and LDH (B). IL-1β 1evels were determined using a commercially available mouse IL-1β ELISA kit. LDH activities in the supernatants and 1% Triton X-100-lysed cells (as a total activity of 100%) were determined using a commercially available LDH assay kit. Data shows the mean ± SD of 3 separate experiments. Values are compared between the absence and presence of Ac-YVAD-CHO. **P<0.01, ***P< 0.001. (C) J774 cells were primed with 10 ng/ml LPS for 4 h and then treated with 3 mM ATP for 90 min. Thereafter, the cells were stained with FAM-YVAD-fmk (a fluorescent labeled caspase-1 inhibitor for inflammasome staining, green) and Hoechst 33342 (for nuclear staining, blue) and photographed with a fluorescence microscope system. Arrowheads indicate the inflammasomes containing the activated caspase-1. Images of cells are representative of 3 separate experiments.