Efferocytosis by Paneth cells within the intestine

Area of Science:

• Gastroenterology
• Immunology
• Cell Biology

Background:

• Efferocytosis, the engulfment of apoptotic cells, is crucial for debris removal and reducing inflammation.
• Intestinal epithelial cells (iECs) undergo apoptosis due to DNA damage from irradiation, chemotherapy, or inflammation.
• The role of phagocytosis in clearing dying iECs, particularly by non-professional phagocytes, is poorly understood.

Purpose of the Study:

• To investigate the efferocytic capacity of Paneth cells in the intestinal crypt.
• To determine if Paneth cells engulf dying intestinal epithelial cells (iECs).
• To assess the role of Paneth cell-mediated efferocytosis in response to irradiation-induced iEC apoptosis.

Main Methods:

• In vitro efferocytosis assays.
• Ex vivo studies using intestinal organoids (enteroids).
• In vivo experiments involving Cre-mediated deletion of Paneth cells in mice.
• Exposure to low-dose cesium-137 (137Cs) irradiation to induce iEC apoptosis.

Main Results:

• Paneth cells were identified as phagocytes capable of engulfing dying neighboring intestinal epithelial cells (iECs).
• Paneth cell-mediated efferocytosis was observed ex vivo and in vivo, particularly after irradiation.
• This efferocytic function of Paneth cells was demonstrated in models mimicking radiation therapy.

Conclusions:

• Paneth cells possess an unexpected phagocytic role in clearing apoptotic intestinal epithelial cells (iECs).
• Paneth cell-mediated efferocytosis contributes to intestinal health, especially following radiation-induced damage.
• These findings reveal a novel mechanism by which Paneth cells support intestinal homeostasis and have implications for inflammatory bowel disease and cancer therapy.