Figure 3. N. gonorrhoeae-induces NLRP3-dependent cell death in THP-1 cells.

A) THP-1 cells were infected with GC at the indicated MOI as described in Figure 2 or treated with staurosporine as a positive control for cell death. After 4 hours the cells were stained with trypan blue and the percentage of viable cells counted using the Nexcelom Cellometer Auto T4. B) Culture supernatants from infected cells were assayed for LDH released from injured or dead cells using a fluorometric assay. Levels of LDH above the background of LDH present in untreated cell culture supernatants are reported as a percent of the maximal LDH activity detected after detergent lysis. C) THP-1 cells were uninfected or infected with GC at an MOI of 0.2 for 20 hours. The cells with compromised membrane integrity were stained with the membrane impermeant dye, propidium iodide (left panels). All cells were subsequently stained with Hoechst 33342 to indicate total cell population (right panels). D) LDH released from cell lines expressing shRNA targeting the inflammasome components ASC or NLRP3 after a 4 hour exposure to GC at MOI of 2.0 was assayed. Results shown are representative of at least 3 independent experiments. Error bars are standard error of the mean for duplicate or triplicate measurements of cell death.