FIGURE 4.

SM934 protected the epithelial barrier function of IECs by regulating the aberrant expression of TJ proteins and apoptosis. Caco-2 cells were treated with or without TNF-α (100 ng/ml) in the absence or presence of SM934 (10 μM) for 24 h (A) Transepithelial electrical resistance (TEER) and (B) permeability of FITC-dextran of Caco-2 cell monolayers were detected. HT-29 cells were pre-incubated with SM934 (10 μM) for 1 h and then exposed to hTNF-α (100 ng/ml) in the presence or absence of SM934 for 24 and 72 h and then using for immunofluorescence and Western blotting assays, respectively. (A) Representative fluorescence images of E-cadherin and ZO-1 stimulated by TNF-α for 24 h in HT-29 cells and measured with a confocal laser-scanning microscope (scale bars, 25 µm). (B) Western blotting assayed the TJ protein expressions of E-cadherin, ZO-1, occludin, claudin-2, and claudin-1 and were treated with TNF-α for 72 h in HT-29 cells. (C) Relative intensity of proteins to GAPDH. (D,E) HT-29 cells were treated with TNF-α in the presence or absence of SM934 in HT-29 cells for 24 h to measure the expression of cleaved caspase-3 by immunofluorescence staining (Scale bars, 25 µm) and Western blot assay. (E) Relative intensity of protein to GAPDH. Data are shown as means ± SEM from three representative experiments. (F) The expression of cleaved -caspase 3 in HT-29 cells was detected by Immunofluorescence staining (Scare bars, 25 μm). (G) The protein level of cleaved caspase-3 in HT-29 cells was detected by western blot. (H) The relative intensity of cleaved-caspase-3 to GAPDH. ^# p < 0.05 and ^## p < 0.01 vs. control group; *p < 0.05 vs. TNF-α group.