Fig. 6.

TPDYFL attenuates acetaldehyde-induced tight junction disruption and occludin dephosphorylation. A: Caco-2 cell monolayers were pretreated with PP2A translocation inhibitor peptide (500 ng/ml) or control peptide prior to acetaldehyde (400 μM) (Acetal) exposure for 5 h. Inulin permeability was measured. Values are means ± SE (n = 4). *Significantly different from control value; #different from value for acetaldehyde group. B: cell monolayers incubated with acetaldehyde for 4 or 5 h in the absence or presence of TPDYFL were fixed and stained for occludin (green) and ZO-1 (red) by immunofluorescence staining method. Fluorescence images were collected via a confocal microscope. C: phospho-threonine was immunoprecipitated from denatured protein extracts of Caco-2 cells exposed to 400 μM acetaldehyde with or without TPDYFL and immunoblotted for occludin. Occludin band densities from different experiments were quantitated by densitometric analysis. Values are means ± SE (n = 3). *Significantly different from control value; #different from value for acetaldehyde group.