Targeting barrier integrity: Pseudoginsenoside RT2 ameliorates ulcerative colitis by driving epithelial renewal via the Wnt/β-catenin pathway.

BACKGROUND

Ulcerative colitis (UC) is a chronic, relapsing inflammatory bowel disease characterized by intestinal barrier dysfunction. Pseudoginsenoside RT2, an ocotillol-type ginsenoside widely present in Panax species, possesses unexplored therapeutic potential for UC.

PURPOSE: This study investigated the efficacy of RT2 against UC and its mechanisms of intestinal barrier protection by driving epithelial renewal.

METHODS

Anti‑UC effects of RT2 were assessed in lipopolysaccharide (LPS)‑stimulated Caco‑2 cells and dextran sulfate sodium (DSS)‑induced mice. Integrated transcriptomic and proteomic analyses were performed to identify key pathways in barrier restoration. Mechanistic validation was conducted using DSS‑induced intestinal organoids (encompassing all epithelial lineages) and LPS‑stimulated IEC-6 cells (non-transformed intestinal epithelial model). Effects on Wnt/β-catenin pathway were assessed with inhibitor ICG-001.

RESULTS

In Caco‑2 cells, RT2 restored transepithelial electrical resistance (TEER), regulated cytokines and upregulated tight junction proteins (TJs). In UC mice, RT2 dose‑dependently ameliorated disease activity index (DAI), improved colon length and histopathology, increased anti‑inflammatory cytokines and reduced pro‑inflammatory cytokines. RT2 enhanced TJs and epithelial markers. Multi-omics analysis linked RT2's benefits to Wnt/β-catenin pathway activation. In organoids, RT2 increased budding and Lgr5 expression. In IEC‑6 cells, RT2 restored TEER, promoted proliferation/migration, suppressed apoptosis and upregulated TJs and epithelial markers. Mechanistically, RT2 facilitated Wnt ligand-receptor binding, leading GSK-3β phosphorylation, disassembly of the destruction complex and β-catenin nuclear translocation. All effects were abolished by ICG‑001.

CONCLUSIONS

RT2 attenuates UC by activating Wnt/β‑catenin pathway, thereby restoring intestinal barrier integrity via driving epithelial renewal, with efficacy comparable to the positive control drug SASP. RT2 represents a promising natural product candidate for UC treatment.