β-Sitosterol Ameliorates Ulcerative Colitis Through Modulation of the AMPK/MLCK Anti-Inflammatory Pathway

Area of Science:

• Gastroenterology
• Pharmacology
• Molecular Biology

Background:

• Ulcerative colitis (UC) is a prevalent inflammatory bowel disease (IBD) with increasing global incidence.
• Understanding the molecular mechanisms of novel therapeutic agents is crucial for effective IBD management.

Purpose of the Study:

• To investigate the anti-inflammatory effects of beta-sitosterol (β-sitosterol) on dextran sulfate sodium (DSS)-induced colitis in mice.
• To elucidate the underlying molecular mechanisms, particularly the role of AMP-activated protein kinase (AMPK) and myosin light chain kinase (MLCK) signaling.

Main Methods:

• A DSS-induced colitis mouse model was used to evaluate β-sitosterol at low (2 mg/kg) and high (6 mg/kg) doses, with sulfasalazine as a positive control.
• Disease Activity Index (DAI) scores, histological analysis, and inflammatory marker (NO, MPO, IL-6, iNOS, IL-10) expression were assessed.
• In vitro studies using lipopolysaccharide (LPS)-stimulated Caco-2 cells and an AMPK inhibitor (Compound C) validated the molecular mechanisms.

Main Results:

• β-sitosterol significantly ameliorated colonic inflammation, reducing DAI scores and improving histology.
• It decreased pro-inflammatory mediators (NO, MPO, IL-6, iNOS) and increased anti-inflammatory IL-10.
• β-sitosterol modulated the AMPK/MLCK pathway, promoting AMPK and suppressing MLCK, an effect confirmed in vitro and dependent on AMPK activity.

Conclusions:

• β-sitosterol demonstrates significant therapeutic potential for ulcerative colitis by modulating the AMPK/MLCK signaling pathway.
• These findings support β-sitosterol as a potential candidate for novel AMPK-targeted therapies in managing inflammatory bowel disease.