Molecular control of tissue-resident macrophage identity by nuclear receptors

Macrophages are key immune cells that reside in almost all tissues of the body, where they exert pleiotropic functions in homeostasis and disease. Development and identity of macrophages in each organ are governed by tissue-dependent signaling pathways and transcription factors that ultimately define specific tissue-resident macrophage phenotypes and functions. In recent years, nuclear receptors, a class of ligand-activated transcription factors, have been found to play important roles in macrophage specification in several tissues. Nuclear receptors are thus important targets for therapies aimed at controlling the numbers and functions of tissue-resident macrophages. This review outlines current knowledge about the critical roles of nuclear receptors in tissue-resident macrophage development, specification, and maintenance.