Pivotal role for skin transendothelial radio-resistant anti-inflammatory macrophages in tissue repair

• Main Authors: Olga Barreiro, Danay Cibrian, Cristina Clemente, David Alvarez, Vanessa Moreno, Íñigo Valiente, Antonio Bernad, Dietmar Vestweber, Alicia G Arroyo, Pilar Martín, Ulrich H von Andrian, Francisco Sánchez Madrid
• Format: Article
• Language: English
• Published: eLife Sciences Publications Ltd 2016-06-01
• Series: eLife
• Subjects: intravital imaging; macrophages; wound healing
• Online Access: https://elifesciences.org/articles/15251

Heterogeneity and functional specialization among skin-resident macrophages are incompletely understood. In this study, we describe a novel subset of murine dermal perivascular macrophages that extend protrusions across the endothelial junctions in steady-state and capture blood-borne macromolecules. Unlike other skin-resident macrophages that are reconstituted by bone marrow-derived progenitors after a genotoxic insult, these cells are replenished by an extramedullary radio-resistant and UV-sensitive Bmi1+ progenitor. Furthermore, they possess a distinctive anti-inflammatory transcriptional profile, which cannot be polarized under inflammatory conditions, and are involved in repair and remodeling functions for which other skin-resident macrophages appear dispensable. Based on all their properties, we define these macrophages as Skin Transendothelial Radio-resistant Anti-inflammatory Macrophages (STREAM) and postulate that their preservation is important for skin homeostasis.