Biology of resident tissue macrophages

Although best known for their phagocytic and immunological functions, macrophages have increasingly been recognised as key players in the development, homeostasis and regeneration of their host tissues. Early during development, macrophages infiltrate and colonise all tissues within the body, developing symbiotically with their host tissues and acquiring unique functional adaptations based on the tissue microenvironment. These embryonic resident tissue macrophages (RTMs) are ontogenically distinct from the later adult bone marrow-derived monocytes, and in some tissues are self-maintained independently of general circulation at a steady state. In this article, we briefly discuss the ontogeny, maintenance and unique tissue adaptions of RTMs focusing on microglia, Kupffer cells, Langerhans cells, intestinal macrophages, cardiac macrophages and tumour-associated macrophages, and highlight their role in development, homeostasis and dysfunction.

Automated summary

Macrophages play a crucial role not only in phagocytosis and immune response, but also in the development, homeostasis, and regeneration of host tissues. Early in development, macrophages infiltrate and colonize all tissues, developing a symbiotic relationship and adapting to the tissue microenvironment. This article briefly discusses the ontogeny, maintenance, and unique adaptations of tissue resident macrophages, focusing on their role in development, homeostasis, and dysfunction in various tissues.