Fig. 8.

Characteristics of OK cell lines stably overexpressing claudin-4. Stable claudin-4 overexpression in OK cell lines was verified by RT-PCR, presented as percentage of vector-transfected control (A), immunoblot probed for HA (B), and by immunostaining (C) a confluent monolayer of OK cells overexpressing claudin-4HA with anti-ZO-1 (green) and anti-HA (red); the scale bars represents 25 μm. Ussing Chamber studies were employed to determine TER (D), absolute permeability to sodium (Na⁺; E), absolute permeability to chloride (Cl⁻; F), ratio of sodium to chloride permeability (P_Na/P_Cl; G), relative contribution of paracellular conductance (G_par), and transcellular conductance (G_trans) to the total epithelial conductance (G_ep; H), and absolute contribution of the changes in paracellular conductance (ΔG_par) and transcellular conductance (ΔG_trans) to the change in total epithelial conductance (ΔG_ep; I) in OK stable cell lines expressing the empty vector or claudin-4HA. OK stable cell lines overexpressing pcDNA 3.1⁺ are abbreviated V and represented with black bars, and those overexpressing claudin-4HA are abbreviated Cl4 and represented with white bars. Data are presented as means ± SE; n ≥ 3 cell lines for each group. *P value < 0.05.