Figure 4. Barrier damage under high glucose conditions was associated with destruction of the apical junctional complex.

(A–C) Left: Representative immunofluorescence images (63x magnification) of apical junction complex proteins of epithelial cells. Epithelial cells were grown on transwell membrane in co-culture with endothelial cells and infected with either medium (‘mock’) or IAV. At 24 hr post-infection, cells were fixed and the nucleus and the relevant tight junction proteins were stained (blue and green, respectively). Right: The percentage of fluorescence intensity in IAV-infected epithelial cells in co-culture relative to mock-infected cells (defined as 100%) at 24 hr post-infection. Statistical comparisons were made using a Student’s unpaired t-test *: p<0.05. Data are pooled from three independent experiments (with three biological replicates per group) and shown as mean ± SEM. JAM-1: junctional adhesion molecule-1. (D) Representative immunofluorescence images (x63 magnification) of epithelial cells infected with either medium (‘mock’) or IAV. At 24 hr post-infection, cells were fixed and the nucleus, claudin 4 and influenza A nucleoprotein were stained (blue, green and red, respectively).