FIG 7.

Inhibition of cytoskeletal rearrangement or MAPK signaling inhibits LTB₄ release. Human neutrophils (4 × 10⁶ for LatA treatment or 8 × 10⁶ for Western blots) were infected with Y. pestis KIM1001 with or without the pCD1 plasmid encoding the T3SS (T3⁺ or T3⁻, respectively); MOI = 100. (A) Concentration of LTB₄ in supernatant from infected neutrophils with indicated Y. pestis strains after pretreatment with vehicle control (LatA⁻) or latrunculin A (LatA⁺) prior to infection. (B) Concentration of LTB₄ in culture supernatants after infection with indicated Y. pestis strains after pretreatment with vehicle control (untreated), the TAK1 inhibitor (5Z)-7-oxozeaenol [(5Z)-7-Oxo], or the ERK inhibitor U0126. (C) Phosphorylation of p38 and (D) ERK during infection with indicated strains after pretreatment with vehicle control (untreated), the TAK1 inhibitor (5Z)-7-oxozeaenol [(5Z)-7-Oxo], or the ERK inhibitor U0126. (E) Phosphorylation of ERK during infection with indicated Y. pestis strains. T3⁺, Y. pestis KIM1001; T3⁻, Y. pestis KIM1001 T3⁽⁻⁾; +J, KIM1001 expressing only yopJ; UT, uninfected. (A and B) Mean ± SEM from 5 biologically independent experiments. (C, D, and E) Mean relative expression calculated from 3 biologically independent Western blots. One-way ANOVA with Sidak’s post hoc test. *, P < 0.05; **, P < 0.01; ***, P < 0.001.