Insights Into Gut Barrier Dysfunction and Metabolic Alterations in Mycophenolate-Induced Enteropathy.

Mycophenolic acid (MPA) is a widely used immunosuppressant whose use is often limited by gastrointestinal toxicity. Gut bacterial hydrolysis of liver-derived MPA glucuronides increases local exposure to MPA, potentially impairing epithelial barrier function and cellular metabolism. To explore the effects of MPA on gut barrier integrity and metabolic pathways in gut epithelial cells, Caco-2 cells were exposed to MPA (10 or 100 μM), and barrier function was assessed by transepithelial electrical resistance (TEER) and lucifer yellow (LY) permeability in both differentiated and early-stage monolayers, while intracellular metabolic changes were investigated using targeted LC-MS/MS metabolomics. In differentiated monolayers, MPA did not significantly alter LY transport or TEER measurements. In contrast, MPA exposure during the early stages of monolayer formation reduced TEER values, 3 days after MPA withdrawal (Day 6; p < 0.01). The effects of 100-μM MPA were still noticeable at Day 10, as confirmed by LY permeability (p < 0.05). Metabolomic profiling clearly separated exposed from control cells (PCA, PC1 + PC2 = 92% variance). At 10 and 100 μM, 9 and 8 metabolites were significantly altered, with 6 common to both doses. Pathway enrichment revealed perturbations mainly in nucleotide synthesis, consistent with altered metabolic activity.