Mechanism and significance of gene expression alteration in phagocytes upon engulfment of apoptotic cells

In our bodies, tens of billions of unnecessary cells appear every day, and these cells are induced to undergo apoptosis, engulfed, and digested by phagocytes such as macrophages. This process is required for tissue homeostasis, and evolutionally conserved among multicellular organisms. Although the role of phagocytosis of apoptotic cells has been thought to be the physical removal of unnecessary cells, recent studies showed that phagocytes change their function upon engulfment of apoptotic cells, accompanied by alteration of gene expression. This review describes the molecular mechanisms and significance of such a novel biological event, focusing on the authors’ studies using fruit fly Drosophila.