Efferocytosis in lung mucosae: implications for health and disease

Chitinase 3-like-1 (CHI3L1) Inhibits Innate Anti-Tumor and Tissue Remodeling Immune Responses by Regulating CD47-SIRPα and CD24-Siglec10-Mediated Phagocytosis

“…This is due to the ability of phagocytosis to prevent secondary necrosis of apoptotic cells and the release of autoantigens and proinflammatory alarmins (7). These antiinflammatory effects are particularly important at mucosal locations such as the lung where the epithelium can turn over every 7-21 days (7)(8)(9)(10)(11)(12)(13). Efferocytosis is an evolutionarily conserved, highly regulated, multistep process that includes mononuclear cell recognition of apoptotic cells and the proper interpretation of the signals they send (7).…”

“…Efferocytosis is an evolutionarily conserved, highly regulated, multistep process that includes mononuclear cell recognition of apoptotic cells and the proper interpretation of the signals they send (7). Specifically, apoptotic cells display diverse “don’t eat me” signals such as CD47, CD24, CD31 and PD-L1 and “eat me” signals such as calreticulin, HMGB1 and annexin-1 (7, 14, 15). The ultimate effect of these signals is additive and depends on the balance of phagocytosis inhibiting and stimulating signals and their respective ligands (7).…”

“…Phagocytosis of apoptotic cells, termed efferocytosis, is paramount for the maintenance of tissue homeostasis (7). This is due to the ability of phagocytosis to prevent secondary necrosis of apoptotic cells and the release of autoantigens and proinflammatory alarmins (7). These antiinflammatory effects are particularly important at mucosal locations such as the lung where the epithelium can turn over every 7-21 days (7)(8)(9)(10)(11)(12)(13).…”

“…These antiinflammatory effects are particularly important at mucosal locations such as the lung where the epithelium can turn over every 7-21 days (7)(8)(9)(10)(11)(12)(13). Efferocytosis is an evolutionarily conserved, highly regulated, multistep process that includes mononuclear cell recognition of apoptotic cells and the proper interpretation of the signals they send (7). Specifically, apoptotic cells display diverse "don't eat me" signals such as CD47, CD24, CD31 and PD-L1 and "eat me" signals such as calreticulin, HMGB1 and annexin-1 (7,14,15).…”

“…Specifically, apoptotic cells display diverse “don’t eat me” signals such as CD47, CD24, CD31 and PD-L1 and “eat me” signals such as calreticulin, HMGB1 and annexin-1 (7, 14, 15). The ultimate effect of these signals is additive and depends on the balance of phagocytosis inhibiting and stimulating signals and their respective ligands (7). This balance plays an important role in malignancies which try to evade phagocytosis by stimulating anti-phagocytotic “don’t eat me” and inhibiting “eat me” receptors and their ligands (7).…”