Fig. 3

P131R-SLC26A3 is involved in the intestinal barrier dysfunction induced by osmotic stress and the [Cl⁻]_i decrease induced by Tenidap. a Caco-2 cells were seeded and cultured in growth medium until a monolayer was formed, the monolayers were starved for 1 h with Hank’s balanced salt solution (HBSS), then treated with HBSS or 150 mM of NaCl in HBSS. P131R-SLC26A3 significantly increased the 150 mM NaCl-induced increase fluorescence value (485/535 nm excitation/emission) compared with WT Caco-2 cells (P = 7.4 × 10⁻⁴), but SLC26A3 over expression prevented the NaCl-induced increase in fluorescence value compared with the empty vector pCS6 (Control) cells. NaCl treatment resulted in similar increase of fluorescence values between WT and control cells (N = 4). b Intracellular Cl⁻ measurements with MQAE (10 mM) were performed in CRISPR/Cas9 edited Caco-2 cells. SLC26A3 inhibitor Tenidap (50 µM) significantly decreased [Cl⁻]_i in P131R-SLC26A3 compared with WT cells. While SLC26A3 over-expressing cells partly prevented decrease of [Cl⁻]_i induced by Tenidap compared with empty vector (pCS6) control cells (N = 4). *P < 0.05, **P < 0.01, ***P < 0.001