Figure 5.

Transforming growth factor-β (TGFβ)/bone morphogenetic protein (BMP) signaling via SMAD4 modulates the expression of Cldn2, Cldn4, Cldn7, and Cldn8 in a cell-autonomous manner. A: wild-type colonoids treated with TGFβ1, BMP2, both, or vehicle for 24 h. B: SMAD4 knockout and control colonoids treated with TGFβ1/BMP2 (T/B) or vehicle for 24 h. Fold change indicates the relative level of mRNA compared with vehicle-treated wild-type controls for indicated genes. Each data point represents a single biological replicate, with biological replicates treated and harvested on different days. Experimental arms were compared using nonparametric Kruskal–Wallis test with post hoc Welch’s t test. Smad7 is used as a positive control to confirm ligand activity. Statistical significance is designated as *P < 0.05, **P < 0.01, ***P < 0.001.