Life after corpse engulfment: phagocytosis of apoptotic cells leads to VEGF secretion and cell growth

Removal of apoptotic cells by neighboring viable cells or professional phagocytes is essential for the maintenance of tissue homeostastis. Here we show that the phagocytosis of apoptotic Jurkat T cells by mouse epithelial cells (HC-11) and peritoneal macrophages leads to the secretion of growth and survival factors. We characterized VEGF as one of these factors which subsequently promote the proliferation of endothelial cells. Further we demonstrate that the phagocytosis of apoptotic bodies inhibits both spontanous and UV-irradiation-induced apoptosis in endothelial and epithelial cells. These effects were not observed when phagocytes had been exposed to viable or necrotic Jurkat T cells. We conclude that phagocytosis of apoptotic cells leads to secretion of growth and survival factors by phagocytes that represents a new form of life-promoting cell-cell interaction.