Two distinct interstitial macrophage populations coexist across tissues in specific subtissular niches

TLDR

Resident tissue macrophages occupy distinct tissue niches and adopt microenvironment‑driven phenotypes that support host defense and tissue homeostasis. The authors used single‑cell RNA sequencing and fate‑mapping of murine lung resident macrophages to examine subset heterogeneity, relationships, and developmental origins. They identified two distinct interstitial macrophage populations: one adjacent to nerve fibers and another near blood vessels that supports vascular integrity and limits inflammatory cell infiltration. Chakarov et al., Science, this issue p.

Abstract

Tissue macrophages have a split personality Resident tissue macrophages (RTMs) reside in various tissue-specific niches during development. They evince microenvironment-directed phenotypes that support host defense and tissue homeostasis. Chakarov et al. used single-cell RNA sequencing and fate-mapping of murine lung RTMs to interrogate RTM-subset heterogeneity, interrelationships, and ontogeny (see the Perspective by Mildner and Yona). In addition to alveolar macrophages, they identified two different interstitial macrophage populations. One population mostly abutted nerve fibers; the other population preferentially localized near blood vessels and appeared to support vessel integrity and inhibit inflammatory cell infiltration into tissues. Science , this issue p. eaau0964 ; see also p. 1154