Lactation-associated macrophages exist in murine mammary tissue and human milk
Abstract
Macrophages are involved in immune defense, organogenesis and tissue homeostasis. Macrophages contribute to the different phases of mammary gland remodeling during development, pregnancy and involution postlactation. Less is known about the dynamics of mammary gland macrophages in the lactation stage. Here, we describe a macrophage population present during lactation in mice. By multiparameter flow cytometry and single-cell RNA sequencing, we identified a lactation-induced CD11c(+)CX3CR1(+)Dectin-1(+) macrophage population (liMac) that was distinct from the two resident F4/80(hi) and F4/80(lo) macrophage subsets present pregestationally. LiMacs were predominantly monocyte-derived and expanded by proliferation in situ concomitant with nursing. LiMacs developed independently of IL-34, but required CSF-1 signaling and were partly microbiota-dependent. Locally, they resided adjacent to the basal cells of the alveoli and extravasated into the milk. We found several macrophage subsets in human milk that resembled liMacs. Collectively, these findings reveal the emergence of unique macrophages in the mammary gland and milk during lactation. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000621076Publication status
publishedExternal links
Journal / series
Nature ImmunologyVolume
Pages / Article No.
Publisher
SpringerOrganisational unit
02207 - Functional Genomics Center Zurich / Functional Genomics Center Zurich
Funding
177164 - Intermicrobial and host-microbial interactions that determine the trajectory of mammalian microbial colorization in early life (SNF)
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