FIGURE 6. PKC inhibitor promoted E. coli-induced TLR4 endocytosis in Siglec-E-deficient mice and inhibited E. coli-induced pro-inflammatory production.

(A) Dendritic cells cultured from three different WT littermates or Siglece ^−/− mice were treated with E. coli 25922 at 37°C for one hour in the presence of indicated protein kinase inhibitors. Flow cytometric analysis was used to determine the cell surface TLR4. Experiments depicted in this figure have been reproduced three times. (B) Cytokines in the cell culture supernatant were analyzed with cytokine bead array. Bone marrow-derived dendritic cells from three different mice were treated with E. coli 25922 in the presence or absence of Syk inhibitor Piceatannol (75 µM) or PKC inhibitor Gö6976 (2.5 µM) at 37°C for 5 hours, and the amount of secreted cytokines were determined. Experiments depicted in this figure have been reproduced two times. (C) Five different WT littermates or Siglece ^−/− mice were pretreated with PKC inhibitor Gö6976 (i.p. injection) for 10 min and then treated with E. coli 25922 (1×10⁶ CFU/mouse, i.v. injection) for one hour. Representative FACS profiles were shown. The bar graphs under the representative FACS profiles present the average MFI value ± SEM from one representative experiment, the color on individual bar in the bar graph corresponds to the color of the line in FACS profiles. Experiments depicted in this figure have been reproduced two times.