Fig. 5.

Metalloprotease inhibitors prevent pathological inflammation during P. aeruginosa infection. (a) Cleavage of internally quenched IL-1β fragment HDAPVRSLN by recombinant LasB incubated with titrations of Marimastat and Ilomastat. (b) IL-1 signalling by THP-1 macrophages 2 h post-infection with PAO1, MOI=10, incubated with titrations of Marimastat and Ilomastat. (c) MIC assay of PAO1 grown overnight in a microtiter plate with titrations of Marimastat and Ilomastat. C57BL/6 mice were intratracheally infected with 10⁷ CFU PAO1 and treated with 25 µg/kg Ilomastat, 25 µg/kg Marimastat, or PBS control. After 24 h, mouse BAL was harvested and (d) CFU plated, (e) neutrophils enumerated, (f) cytokines measured by enzyme-linked immunosorbent assay. (g) Representative histology sections cytological smears of bronchoalveolar lavage fluid prepared with differential MGG stain, scale = 40 μm. (h) CFU plated from kidneys to quantify dissemination. Error bars show mean ± s.d, n = 4 (a-c), n = 5 (d-g), and represent at least 3 independent experiments. Statistical analysis by ANOVA with Tukey post-test, *P < 0.05, **P < 0.005, ***P < 0.0005.