Fig. 2.

Selective activation of the PXR on Caco-2 IECs maintains tight-junction integrity in epithelial monolayers. (A) Caco-2 monolayers grown for 14 days postconfluence were pretreated with rifaximin (Rifx; 10 μM), a selective PXR agonist, for 1 hour prior to exposure to TNFα (10 ng/ml) and IFNγ (20 ng/ml) for 16 hours. (B) The degree of ZO-1 mislocalization, an indicator of tight-junction disruption, was quantified by using ImageJ to measure the length of ZO-1 staining and expressing it as a ratio of the length of total cell-cell contact. A value of 100 indicates ZO-1 staining is maintained over the entire cell-cell interface. A value >100 indicates ZO-1 staining is disrupted over the cell-cell interface. **P < 0.005 compared with control; ##P < 0.005 compared with TNFα/IFNγ group (n = 5–9 replicates from four separate experiments).