Wogonoside alleviates colitis by improving intestinal epithelial barrier function via the MLCK/pMLC2 pathway

Area of Science:

• Gastroenterology
• Pharmacology
• Molecular Biology

Background:

• Intestinal epithelial barrier dysfunction is a key factor in inflammatory bowel disease (IBD) pathogenesis, often involving myosin light chain kinase (MLCK) activation.
• Wogonoside is known to maintain intestinal homeostasis, but its specific role in modulating intestinal barrier function during colitis was unclear.

Purpose of the Study:

• To investigate the protective effects of wogonoside against intestinal barrier dysfunction in colitis.
• To elucidate the underlying mechanism involving the MLCK/pMLC2 pathway in both in vivo and in vitro models.

Main Methods:

• Assessed Caco-2 cell monolayers for barrier function (TER, hyperpermeability, tight junction proteins) after TNF-α treatment with and without wogonoside.
• Induced colitis in mice using dextran sulfate sodium (DSS) to study wogonoside's pharmacodynamics, including cytokine levels (IL-13, IFN-γ), bacterial translocation, and tight junction integrity.
• Analyzed MLCK/pMLC2 pathway proteins via Western blot and performed molecular docking of wogonoside with MLCK.

Main Results:

• Wogonoside improved transepithelial electrical resistance (TER), reduced hyperpermeability, and restored tight junction proteins (occludin, ZO-1, claudin-1) in Caco-2 cells.
• In colitic mice, wogonoside decreased bacterial translocation, reduced pro-inflammatory cytokines (IL-13, IFN-γ), and ameliorated tight junction destruction.
• Wogonoside inhibited cytoskeletal rearrangement, suppressed MLCK expression, and reduced MLC2 phosphorylation, with molecular docking showing high affinity to MLCK.

Conclusions:

• Wogonoside alleviates colitis by protecting the intestinal barrier through the MLCK/pMLC2 signaling pathway, impacting tight junctions.
• This mechanism explains the therapeutic success of S. baicalensis in treating ulcerative colitis (UC).