Figure 6

Western blot analysis of the hydrolysis of TJ and adherens proteins in Caco-2 cells by various proteases in IIL ESPs. A Caco-2 cell monolayers were incubated with IIL ESPs pre-treated with various inhibitors (1.25 mM PMSF, 24 μM E-64, 2.4 mM 1,10-Phe or 10 μM pepstatin) alone or in mixtures at 37 ℃ for 2 h. Normal Caco-2 cells treated with 0.1% DMSO were used as a negative control, and 20 μg/mL ESP without inhibitors was used to assess the hydrolysis of TJ proteins. The expression of TJ and adherens junction proteins was analysed by Western blotting. GAPDH was used as an internal reference control. B–E Densitometric analysis of the bands obtained in A for E-cad (B), occludin (C), claudin-1 (D) and claudin-2 (E) relative to the GAPDH band. *P < 0.05 compared to normal Caco-2 cells.