Perivascular localization of macrophages in the intestinal mucosa is regulated by Nr4a1 and the microbiome

Nat Commun. 2020 Mar 12;11(1):1329. doi: 10.1038/s41467-020-15068-4.

Abstract

While the ontogeny and recruitment of the intestinal monocyte/macrophage lineage has been studied extensively, their precise localization and function has been overlooked. Here we show by imaging the murine small and large intestines in steady-state that intestinal CX3CR1+ macrophages form an interdigitated network intimately adherent to the entire mucosal lamina propria vasculature. The macrophages form contacts with each other, which are disrupted in the absence of microbiome, monocyte recruitment (Ccr2-/-), or monocyte conversion (Nr4a1-/-). In dysbiosis, gaps exist between the perivascular macrophages correlating with increased bacterial translocation from the lamina propria into the bloodstream. The recruitment of monocytes and conversion to macrophages during intestinal injury is also dependent upon CCR2, Nr4a1 and the microbiome. These findings demonstrate a relationship between microbiome and the maturation of lamina propria perivascular macrophages into a tight anatomical barrier that might function to prevent bacterial translocation. These cells are also critical for emergency vascular repair.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CX3C Chemokine Receptor 1 / metabolism
  • Colitis / pathology
  • Dextran Sulfate
  • Dysbiosis / pathology
  • Gastrointestinal Microbiome*
  • Intestinal Mucosa / blood supply*
  • Intestinal Mucosa / cytology*
  • Macrophages / metabolism*
  • Mice, Inbred C57BL
  • Monocytes / metabolism
  • Nuclear Receptor Subfamily 4, Group A, Member 1 / metabolism*
  • Receptors, CCR2 / metabolism
  • Wound Healing

Substances

  • CX3C Chemokine Receptor 1
  • Nr4a1 protein, mouse
  • Nuclear Receptor Subfamily 4, Group A, Member 1
  • Receptors, CCR2
  • Dextran Sulfate