Lymphocytes and Antibiotics Alter the Tight Junction Complex in Inflammatory Bowel Disease

The tight junction complex (TJ) is altered in patients with inflammatory bowel disease (IBD). It is unclear if alterations in the TJ predispose patients to IBD or are the result of the inflammatory process. Lymphocytes are known to play an important role in the inflammation and pathophysiology of IBD. A mutation in the NOD2 gene predisposes a patient to IBD. Ciprofloxicin (Cipro) is an antibiotic that is also used to treat IBD. We hypothesize that agents that exacerbate IBD, such as lymphocytes, and improve IBD, such as Cipro, will also alter the tight junction complex. Methods T84 cells were co‐cultured with B‐cell lines from patients with and without IBD for 48 hours. Additional T84 cells were treated with 0, 5, or 50ng/ml of interferon gamma (IFNγ) with and without 100mg of Ciprofloxicin (Cipro) for 48 hours. IFNγ was used to simulate the inflammatory state of IBD. Western blot performed for ZO‐1, occludin, and claudin‐1. The B‐cell lines used were assayed for the 3 clinically relevant NOD2 mutations. Statistics were ANOVA. Results 50% of the B‐cell lines used contained the 3020InsC mutation of the NOD2 gene. When T84 cells were treated with B‐cells with a NOD2 mutation there was a statistically significant decrease in occludin compared to untreated T84 cells. There was no change in occludin in T84 cells treated with B‐cell lines with wild‐type NOD2. ZO‐1 was not significantly changed. See figure 1. When cells were treated with Cipro there was a significant increase in ZO‐1 seen with 100mg/ml. See figure 2. The other TJ proteins trended toward an increase but were not significantly changed. Conclusions 1. B‐cells from patients with a NOD2 mutation decreased the TJ transmembrane protein occludin, while B‐cells from patients without a NOD2 mutation had no effect. 2. Cipro, which is used to treat IBD, improved the TJ by increasing ZO‐1. Together these data suggest that agents that alter the course of IBD may have their alterations mirrored in the tight junction complex.