Macrophage’s little helper: vitamin A directs alternatively activated monocyte-derived macrophages to tissue-resident macrophages

Tissue-resident macrophages originate from the yolk sac in a Myb-independent manner and populate all organs during embryogenesis.These macrophages are a heterogeneous self-renewing population that adapt to the organ-specific local environment to contribute to tissue homeostasis.Depending on the age,organ and inflammatory conditions,macrophages that are derived from hematopoietic stem cells(HSCs)in a Myb-dependent manner may also infiltrate organs and develop into tissueresident macrophages.