Figure 3

Analysis of host kinase function in Yersinia -mediated immune suppression using small molecule inhibitors. (A) RE-luc2P-HEK293 cells were pretreated with 1μM OSI-930 (green), 20μM TBB (blue), 10μM CKI-7 (purple), or 10μM H-89 (orange) for 16 h and infected with Y. enterocolitica WA or Y. pestis Ind195 at MOI 1 and 20, respectively, for 1 h. Following stimulation with 10 ng/ml TNF-α at 5 h post-infection, luciferase activity was measured 24 h post-infection. Results were determined from two independent experiments performed in triplicate. A ‘*” denotes that the % NF-κβ inhibition using the inhibitors was significantly different (p<0.05) compared to the no drug control (black). The relative NF-κB inhibition by Yersinia infection was determined as a percentage of luciferase activity in bacteria-infected cells relative to luciferase activity in bacteria-free control cells. (B) THP-1 cells were pretreated with the small molecules and infected with Y. enterocolitica WA or Y. pestis Ind195 at MOI 5 and 20, respectively, for 1 h. TNF-α levels were determined by ELISA on conditioned media collected 24 h post-infection. Results were determined from two representative independent experiments performed in quadruplicate. A ‘*” denotes that TNF-α release using inhibitors was significantly different (p<0.05) compared to the no drug control. Cytokine release in response to purified LPS from E. coli 055:B5 (5μg/ml, light blue) was used as a control for pro-inflammatory mediator signaling. (C) Normal HDC were pre-treated with the small molecules for 18 h prior to infection with Y. enterocolitica WA or Y. pestis KIM5-. Bacterial infection was stopped 1 h post-infection with 170 μg/ml chloramphenicol. TNF-α levels were determined by ELISA on conditioned media collected 24 h post-infection. Statistical analysis was performed on data from 3 experiments performed in quadruplicate. TNF-α release in response to all inhibitor treatments were statistically significant (p<0.05) compared to no drug controls.