Tissue-resident macrophages: from zebrafish to mouse

Tissue-resident macrophages (TRMs), generally found in tissues under normal physiological conditions, play crucial roles not only in immunity but also in tissue development and homeostasis. Because of their diverse functions, dysregulation of their development and function has been implicated in many human disorders. In the past decade, a great deal of extensive studies have been conducted in various model organisms with cutting-edge technologies to explore the origin and function of TRMs. In this review, we summarize the recent findings on TRMs in mouse and zebrafish and compare the similarity/differences between these two species.