1. The GBS hemolytic pigment/lipid toxin induces caspase 1 activation and pyroptosis THP‐1 macrophages were treated with GBS pigment, and caspase 1 activation was measured by flow cytometry using a FLICA reagent.
The GBS hemolytic pigment/lipid toxin induces caspase 1 activation and pyroptosis THP‐1 macrophages were treated with GBS pigment, and caspase 1 activation was measured by flow cytometry using a FLICA reagent. Pigment treatment of the scrambled shRNA control cell line induces more caspase 1 activation compared to the shNLRP3 cell line, demonstrating that the pigment activates caspase 1 exclusively through the NLRP3 inflammasome. Results are representative of three independent experiments. WT THP‐1 macrophages were treated with the caspase 1 inhibitor Z‐YVAD‐FMK, the caspase 3/7 inhibitor Z‐DEVD‐FMK, or DMSO only prior to treatment with the GBS pigment. YVAD is able to significantly decrease cytotoxicity in cells treated with GBS pigment, demonstrating that caspase 1 is required for GBS pigment‐mediated cell death, characteristic of pyroptosis, while DEVD had no effect. Data are average of three independent experiments, error bars ± SEM. Significance was determined using Bonferroni's multiple comparison test following ANOVA (n = 3, ****P < 0.0001, ***P = 0.0002, *P = 0.014).
Christopher Whidbey et al. EMBO Mol Med. 2015;7:
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