Boosting Apoptotic Cell Clearance by Colonic Epithelial Cells Attenuates Inflammation In Vivo

Area of Science:

• Immunology
• Cell Biology
• Gastroenterology

Background:

• Efficient clearance of apoptotic cells is crucial for maintaining tissue homeostasis.
• The role of phagocytic receptors, like Brain-specific angiogenesis inhibitor 1 (BAI1), in regulating in vivo efferocytosis during inflammation is not fully understood.
• Intestinal epithelial cells' role in efferocytosis is under-investigated.

Purpose of the Study:

• To investigate whether enhancing in vivo corpse clearance can be beneficial for inflammatory conditions.
• To determine the role of the phagocytic receptor BAI1 in colonic inflammation and apoptotic cell clearance.
• To explore the therapeutic potential of boosting BAI1-mediated efferocytosis in intestinal epithelial cells.

Main Methods:

• Utilized a colonic inflammation mouse model.
• Generated and analyzed BAI1-deficient mice and transgenic mice overexpressing BAI1.
• Assessed levels of apoptotic cells, inflammatory cytokines, and disease severity.
• Differentiated the roles of BAI1 expression in intestinal epithelial cells versus myeloid cells.

Main Results:

• BAI1 expression was downregulated during colonic inflammation.
• BAI1-deficient mice exhibited exacerbated colitis, reduced survival, and increased uncleared apoptotic cells and inflammatory cytokines.
• Transgenic mice overexpressing BAI1 showed reduced apoptotic cells, inflammation, and disease severity.
• Boosting BAI1-mediated uptake specifically in intestinal epithelial cells was key to attenuating inflammation.
• A signaling-deficient BAI1 transgene failed to confer similar benefits.

Conclusions:

• In vivo apoptotic cell clearance can be enhanced to regulate tissue inflammation.
• Targeting BAI1-mediated efferocytosis in intestinal epithelial cells represents a potential therapeutic strategy for inflammatory bowel diseases.
• BAI1 signaling is critical for its beneficial effects in mitigating colitis.