Fig. 1.

PIP peptides can reversibly affect the trans-epithelial electrical resistance (TEER) properties across confluent, polarized monolayers of Caco-2 cells in vitro. Changes in percentage (%) of initial TEER values measured over time following apical application of PIP peptide 250 or peptide 640 at designated concentrations demonstrated concentration- and time-dependent action. Arrow represents time point when the PIP peptide in the apical compartment was replaced with PBS (washout). Control is where PBS was added to the apical surface with no peptide. Data are means ± SD, n = 6 for control and n = 5 for all peptide groups. One-way ANOVA showed that the data sets were significantly different from each other (p < 0.0001). Bonferroni post-tests showed that 10 mM peptide 250 (p < 0.01), 20 mM peptide 250 (p < 0.001) and 10 mM peptide 640 (p < 0.001) were significantly different from control.