# Insights Into Gut Barrier Dysfunction and Metabolic Alterations in Mycophenolate‐Induced Enteropathy

## TL;DR

This study shows that mycophenolic acid can weaken gut cell barriers and disrupt metabolism, especially in early-stage cells, which may explain its gastrointestinal side effects.

## Contribution

The study reveals that MPA exposure during early cell development impairs gut barrier function and alters nucleotide metabolism.

## Key findings

- MPA exposure during early cell development reduces barrier function, as shown by lower TEER values.
- Metabolomic analysis shows MPA alters nucleotide synthesis pathways, with 6 metabolites commonly affected at both doses.
- MPA effects on barrier function persist even after drug withdrawal.

## Abstract

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.

Mycophenolic acid (MPA) is an important drug used to prevent organ rejection, but it is linked to gastrointestinal side effects. In this study, we used a digestive cell line to examine how MPA affects barrier function and cellular metabolism. Mature, differentiated cell layers were mostly unchanged, but early‐stage cell layers became weaker after MPA exposure, even days after the drug was removed. We also detected distinct metabolic changes, especially in pathways involved in nucleotide production. Overall, these findings suggest that MPA may disrupt vulnerable gut cells by weakening their barrier and altering key metabolic processes.