Fig. 8.

Occludin knockdown attenuates serine protease-induced increase in TER. A: SCBN cells were treated with 50, 100, or 300 nM occludin siRNA for 48 h and knockdown assessed by Western blotting. B and C: representative tracings of SCBN cells transfected with 300 nM occludin siRNA for 48 h, and treated with trypsin (B, n = 6–9) or matriptase (C, n = 4). Controls include untransfected cells, and RNAiMAX Lipofectamine with or without scrambled siRNA. Baseline TER (n = 10–14) (D) and change in TER 15 min post serine protease treatment (E and F) were assessed. Occludin siRNA induced a significant reduction in baseline TER and attenuated the trypsin- and matriptase-induced increase in TER. *P < 0.05, **P < 0.01 compared with scrambled control.