Fig 1: Expression of ADH1B and ALDH2 alters ethanol and acetaldehyde-induced tight junction disruption and barrier dysfunction.Caco-2 cells were transfected with ADH1B (closed symbols) or vector (open symbols). Expression of ADH1B in transiently transfected cells was determined by immunoblot analysis (A). Vector and ADH1B-transfected cells in transwell inserts were incubated with varying concentrations of ethanol. At 3-hour incubation, TER (B) and unidirectional flux of FITC-inulin (C) were measured. Fixed cell monolayers were stained for occludin (green) and ZO-1 (red) by immunofluorescence method (D). Values in panels B and C are mean ± SEM (n = 6). Asterisks indicate values that are significantly (p < 0.05) different from corresponding values for control cell monolayers. Caco-2 cells were transfected with ALDH2 or vector. Expression of ALDH2 in transiently transfected cells was determined by immunoblot analysis (E). Vector (open symbols) and ALDH2 (closed symbols)-transfected cells in transwell inserts were incubated with varying concentrations of acetaldehyde. At 4-hour incubation, TER (F) and unidirectional flux of FITC-inulin (G) were measured. Fixed cell monolayers were stained for occludin (green) and ZO-1 (red) by immunofluorescence method (H). Values in panels B and C are mean ± SEM (n = 6). Asterisks indicate values that are significantly (p < 0.05) different from corresponding values for control cell monolayers.