Figure 6.

Down-regulated PKC activity is involved in SpvB-mediated barrier dysfunction. (A) Caco-2 cells were treated with the indicated S. typhimurium strains at an MOI of ~100. Western blot analysis and densitometry plots showing the activation of PKC. (B) 293T cells were transfected with pEGFP-N1-SpvB or pEGFP-N1 for 24 h. Western blot analysis showing the expression of HA-SpvB and the activation of PKC. (C–F) Caco-2 cells were pre-treated with the inhibitor of PKC activation, Bisindolylmaleimide I (1 µM), 1 h prior to infection with the indicated S. typhimurium strains. 4 kDa FITC-dextran flux (C) and bacterial translocation (D) across Caco-2 monolayers were measured 3 h.p.i. (E, F) Western blot analysis and densitometry plots of AJC proteins from the detergent-insoluble fraction (E, membrane) and detergent-soluble fraction (F, cytosolic) of Caco-2 cells 3 h.p.i. Data are presented as the mean ± SEM. *P < 0.05; ns, not significant.