Figure 5: Upregulation of TLR9 in CD73−/− decreased expression of tight-junction associated proteins observed in the colons of CD73−/− mice compared to WT mice. (a) Colonic permeability was determined in WT and CD73−/− mice. Serum concentrations of FITC-Dextran (MW 10,000) in WT (gray bar) and CD73−/− (black bar) mice were obtained following rectal administration of 10 KDa FITC-Dextran (0.5 mg/Kg) and measuring FITC-Dextran in the blood 1 hour later. Results are expressed as mean ±SEM, 𝑛 = 5 , * 𝑃 < 0 . 0 5 ). Results are expressed as (mean ±SEM, 𝑛 > 3 , * 𝑃 < 0 . 0 5 ) relative fluorescence compared to WT. (b) Colons of WT (gray bars) and CD73−/− (black bars) were analyzed for mRNA expression of the adhesion molecules JAM-A, αCatenin, and Claudin-2. Results are expressed as (mean ±SEM, 𝑛 = 3 , * 𝑃 < 0 . 0 5 , ** 𝑃 < 0 . 0 1 ) fold increase in CD73−/− compared to WT. (c) Fluorescent microscopy of colons from naïve WT (left panel) and CD73−/− (right panel) mice stained for JAM-A (green). (d) Colons were isolated from CD73−/− or WT mice over the course of IBD and analyzed for TLR9 mRNA expression by real-time PCR. Results are presented as TLR9 expression level relative to the housekeeping gene PGK1. (Representative of 3 experiments.)