Mucosal Macrophages Govern Intestinal Regeneration in Response to Injury

Area of Science:

• Gastroenterology
• Immunology
• Regenerative Medicine

Background:

• Radiation-induced enteritis significantly impairs quality of life in cancer patients.
• Radiation injury depletes intestinal stem cells, necessitating a regenerative response for healing.
• Mechanisms activating the intestinal regenerative program post-radiation are not well understood.

Purpose of the Study:

• To investigate the role of macrophages in radiation-induced enteritis.
• To elucidate the cellular and molecular mechanisms of macrophage-mediated intestinal regeneration.
• To explore therapeutic potential of targeting macrophages for enhanced healing.

Main Methods:

• Induced radiation-induced enteritis in mice and analyzed macrophage recruitment.
• Utilized coculture systems of intestinal organoids and macrophages (mouse and human).
• Employed in vivo macrophage ablation, lineage tracing, RNA sequencing, and cell trajectory analysis.

Main Results:

• Macrophages are recruited to intestinal stem cell niches, promoting fetal-like reprogramming and epithelial proliferation.
• Macrophage ablation resulted in impaired intestinal regeneration.
• Neuregulin 1 and osteopontin were identified as key secreted molecules mediating regeneration.
• Macrophage-driven regeneration was conserved in human intestinal organoid models.

Conclusions:

• Macrophages are essential for intestinal regeneration, extending beyond their immune functions.
• Therapeutic strategies targeting macrophages could enhance intestinal repair and improve patient quality of life.