Figure 10.
The positive charge bias of paracellular permeability enhanced by PIP 640 is dependent upon claudin-2 expression. A) Representative immunoblots demonstrating changes in MLC-pS19 and claudin-2 levels 60 min after apical application of 1 mM of PIP 640 to claudin-2 knock-down Caco-2 (KD) or control Caco-2 knock-down (CKD) cell monolayers in vitro. B) Quantitative analysis of changes in MLC-pS19 and claudin-2 induced by PIP 640 shown in A). C) Changes in TEER relative to initial values 60 min after apical application of 1 mM PIP 640 to CKD or KD Caco-2 cell monolayers. D) Cumulative apical to basal transport across Caco-2 monolayers of fluorescent DEAE-dextran (+ve) or CM-dextran (-ve) compared to neutral dextran (all 4-kDa in size) 60 min after apical application of 1 mM PIP 640. Data are means ± SEM of 3 independent experiments, with n=6 (*P < 0.05 and **P < 0.01, ***P < 0.001, ****P < 0.0001).