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. 2020 Oct 19;9:e59022. doi: 10.7554/eLife.59022

Figure 1. Shigella infection appears to suppress the NAIP–NLRC4 inflammasome.

Figure 1.

(A) Shigella infection (MOI 10) of C57BL/6 WT or Nlrc4–/– bone-marrow-derived macrophages (BMMs). Cell death was measured 30 min post-infection (after spinfection, invasion, and washes) by propidium iodide uptake and reported as percent death relative to 100% killing by treatment with Triton X-100. (B) Cell death of Shigella infected THP1 WT, CASP1–/– or NLRC4–/– cells as in (A). Cell death was measured 30 min post-infection. (C) Cell death of THP1 WT, CASP1–/– or NLRC4–/– cells treated with 10 μg/mL PA alone or in combination with 10 μg/mL LFn-MxiH ('NeedleTox'). Cell death was measured 4 hr post-challenge. (D) Human NAIP–NLRC4 inflammasome reconstitution in 293T cells. Inflammasome activation was measured by CASP1-dependent processing of pro-IL-1β to p17 by co-transfection of an empty vector, pGFP-MxiH or pGFP-MxiI, or by treatment with 10 μg/mL PA alone or in combination with 10 μg/mL LFn-MxiH. (E) Colchicine (1 μM)-treated AIM2–/– THP1 cells were either left uninfected or infected for 1 hour (after spinfection, invasion, and washes) with WT or BS103 Shigella (MOI 10), and then treated with 10 μg/mL PA alone, PA + 1.0 μg/mL LFn-MxiH ('NeedleTox'), or 10 μM nigericin. Cell death was measured by PI staining and is reported as cell death relative to TX-100-treated controls per infection type. Data are representative of at least three independent experiments. Mean ± SD is shown, unpaired t-test with Welch’s correction: *p < 0.01, **p < 0.001, ***p < 0.0001, ns = not significant (p > 0.05).