Since accumulation of YopJ/P in host cells upon Yersinia infection has been previously linked to cell death via activation LB-100 of apoptotic pathways, we assessed cell viability at various MOIs. We registered no decrease in cell viability in drug-free cells or cells treated with the JNK1 inhibitor, even after 20 h post-infection of THP-1 cells with virulent Y.entorocolitica at MOI 2 of the assay. (data not shown) Taken together, these findings indicate that c-KIT function is exploited

by Yersinia T3SS to suppress production of key transcription factors and cytokines involved in the regulation of the host immune response. Figure 5 c-KIT signaling is targeted by Yersinia T3SS to suppress pro-inflammatory immune response. (A) THP1 cells were pre-treated with 1 μM OSI-930 or 1 μM BI-78D3 for 18 h or NU7026 research buy untreated prior to infection with Y. enterocolitica (pYV+)

and Y. enterocolitica (pYV-) at MOI 2. The RNA levels are presented as fold change versus untreated THP1. Data is shown from three independent infection experiments performed in duplicate. A ‘*” denotes that relative RNA levels were significantly different (p<0.05) in OSI930-treated cells compared to untreated or BI-78D3-treated cells. (B) THP-1 cells were transfected with 50 nM siRNA targeting c-KIT or control (si-CTL) and incubated for 48 h. RNA levels are presented relative to transcript levels in siRNA-treated versus untreated THP-1. Data is shown from two representative experiments. A ‘*” denotes that relative PF-4708671 RNA levels were significantly different (p<0.05) in si-cKIT-treated cells compared to si-CTL-treated cells. (C) THP-1 cells were transfected with 50 nM siRNA against c-KIT (si-cKIT) or control (si-CTL) siRNA and incubated for 72 h prior to infection with Y. enterocolitica

FXR agonist WA at MOI 2 for 1 h. Gene transcript levels are depicted as a relative ratio to uninfected siRNA-treated THP-1 cells. Data is shown from three independent experiments performed in duplicate. A ‘*” denotes that relative RNA levels of immune genes were significantly different (p<0.05) in si-cKIT-treated cells compared to si-CTL-treated cells. (D) THP-1 cells, untreated or pretreated with 1μM OSI-930 for 5 h, were infected with Y. enterocolitica WA at MOI 40 for 45 min. Cell nuclei were purified, labeled with mouse anti-NF-κB RelA, and analyzed by flow cytometry. (left panel) The mean channel fluorescence was used to determine the fold change of RelA in the nuclei of Yersinia-infected compared to untreated THP-1 cells (middle panel). The statistical data was derived from two independent experiments (right panel). Figure 6 Yersinia infection activates c-KIT tyrosine phosphorylation.