Figure 5.

Increase in paracellular permeability of small molecules by PMTPV and CLDN1 siRNA. (A,B) A549 cells cultured on transwell plates were incubated in the presence and absence (vehicle) of 100 μM PMTPV for 24 h. TER was measured using a volt ohmmeter. LY (10 μM) or DXR (10 µM) was added to the apical compartment. After incubation at 4 °C for 1 h, the solution in the basal compartment was collected. The concentration of DXR and LY was measured using an Infinite F200 microplate reader. (C–E) A549 cells were transfected with negative (si-Neg) or CLDN1 siRNA (si-CLDN1). The protein level of CLDN1 was examined by Western blotting and represented relative to the values in the cells transfected with negative siRNA. Paracellular permeability was estimated by TER, LY flux, and DXR flux. n = 4–6. ** p < 0.01 compared with vehicle or si-Neg. NS, p > 0.05.