SOX9 impairs the intestinal mucosal barrier integrity by targeting CLDN8. a-b, TEER and FD4 permeability alterations in the Caco-2 cell monolayer. c-d, Overexpression and knockdown of SOX9 in Caco-2 cells. SOX9 mRNA (left panel) and CLDN8 mRNA (middle panel), and relevant proteins (right panel). e-f, Overexpression and knockdown of SOX9 in NCM460 cells. All Data are shown as means ± SEM in (a), (b), (c), (d), (e) and (f). Student's t-test were used for comparison between two groups. ns: no significant difference, *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 as compared with the control.