The Arp2/3 complex maintains gut epithelial integrity under mechanical challenge.

Area of Science:

• Cell Biology
• Gastroenterology
• Biophysics

Background:

• The gut epithelium forms a critical barrier against external insults and mechanical stress.
• Maintaining intestinal barrier integrity is crucial for homeostasis, despite continuous challenges like microbial exposure and tissue renewal.
• Actin regulators, such as the Arp2/3 complex, are implicated in cell adhesion and cytoskeletal dynamics at cell junctions.

Purpose of the Study:

• To investigate the role of the Arp2/3 complex in regulating intestinal epithelial integrity under mechanical stress.
• To elucidate the mechanisms by which Arp2/3 influences barrier function and epithelial stability.

Main Methods:

• Utilized a gut epithelium-specific, inducible Arpc4 knockout mouse model.
• Employed ex vivo cultured intestinal slices and intestinal epithelial organoids.
• Assessed intestinal permeability, epithelial morphology, and tight junction protein localization.

Main Results:

• Loss of Arp2/3 function in the gut epithelium led to increased intestinal permeability, epithelial fracturing, and lethality.
• Arp2/3 depletion disrupted tight junction protein localization, compromising epithelial stability.
• Functional defects were dependent on mechanical challenge and elevated actomyosin contractility.

Conclusions:

• The Arp2/3 complex is a critical regulator of intestinal epithelial homeostasis and barrier function under mechanical stress.
• Arp2/3 ensures tight junction stability, preventing epithelial dysfunction and failure.
• Findings suggest Arp2/3 as a potential therapeutic target for inflammatory disorders associated with barrier dysfunction.