Figure 6.

TWEAK inhibits the LPS-induced activating of Fn14 pathway. Treatment of porcine small intestinal epithelial cells (SIEC02) with recombinant TWEAK reduces LPS-induced super Fn14 expression (A) as well as TLR4/Fn14 expression by suppressing the activation of MyD88 and canonical NF-κB pathways in cells. Representative blots are shown in (B) and the histograms in (C) show the results of densitometric analysis of TNF-α expression in different treated SIEC02 (normalized to β-actin to correct for protein loading). SIEC02 seeded in a 24-well plate stimulated with LPS for 24 h were treated with recombinant TWEAK and after 24 h the number of viable cells was measured using the trypan blue exclusion method (D). Representative fluorescence photomicrographs show localization of Occludin (green) in SIEC02 stimulated with LPS in the presence of increasing concentrations of recombinant TWEAK for 24 h (E). Nuclei were counterstained blue with DAPI. Scale bars = 50 μm. The expression levels of Occludin were analyzed by Western blot analysis (F). Representative blots are shown in the upper panel and the histograms in the under panel show the results of densitometric analysis of Occludin protein expression (normalized to β-actin to correct for protein loading). Data are expressed as mean ± SEM (n = 3). ^*P < 0.05, ^**P < 0.01, compared with data on untreated control cells.