Changes in Epithelial Barrier Function in Response to Parasitic Infection: Implications for IBD Pathogenesis

Area of Science:

• Gastroenterology
• Immunology
• Cell Biology

Background:

• Mast cells (MCs) are involved in epithelial barrier dysfunction in inflammatory bowel diseases.
• Mast cell proteinases and tight junction (TJ) proteins play roles in gut barrier integrity.

Purpose of the Study:

• To investigate the kinetics of mast cell proteinases and TJ proteins in a rat model of postinfectious gut dysfunction.
• To elucidate the molecular mechanisms underlying epithelial barrier alterations after gut infection.

Main Methods:

• Jejunal tissues from control and infected rats were analyzed.
• Immunostaining and RT-qPCR were used to assess MCs and TJ protein expression.
• Epithelial barrier function was evaluated using in vitro (Ussing chambers) and in vivo models.

Main Results:

• Intestinal inflammation led to overexpression of MC chymases and hyperplasia.
• Down-regulation of occludin and claudin-3, with overexpression of claudin-2, was observed post-infection.
• Reduced proglucagon expression and increased epithelial permeability were associated with these molecular changes.

Conclusions:

• Mast cell proteinase expression and localization follow a time-dependent pattern post-infection.
• Altered TJ protein expression contributes to reduced epithelial tightness and increased permeability.
• These findings provide a molecular basis for post-infectious gut barrier dysfunction.