In vivo imaging reveals unique neutrophil transendothelial migration patterns in inflamed intestines

Mucosal Immunol. 2018 Nov;11(6):1571-1581. doi: 10.1038/s41385-018-0069-5. Epub 2018 Aug 13.

Abstract

Neutrophil (PMN) infiltration of the intestinal mucosa is a hallmark of gastrointestinal inflammation, with significant implications for host defense, injury and repair. However, phenotypic and mechanistic aspects of PMN recruitment in inflamed intestines have not been explored in vivo. Using novel epithelial/PMN fluorescence reporter mice, advanced intravital imaging and 3D reconstruction analysis, we mapped the microvasculature architecture across the intestinal layers and determined that in response to Salmonella/endotoxin-induced inflammation, PMN transendothelial migration (TEM) was restricted to submucosal vessels. PMN TEM was not observed in villus or crypt vessels, proximal to the epithelium that underlies the intestinal lumen, and was partially dependent on (C-X-C motif) ligands 1 (CXCL1) and 2 (CXCL2) expression, which was found to be elevated in the submucosa layer. Restricted PMN extravasation at the submucosa and subsequent PMN interstitial migration may serve as a novel regulatory step of PMN effector function and recruitment to the luminal space in inflamed intestines.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cells, Cultured
  • Chemokine CXCL1 / metabolism
  • Chemokine CXCL2 / metabolism
  • Green Fluorescent Proteins / genetics
  • Humans
  • Imaging, Three-Dimensional
  • Inflammation / immunology*
  • Intestinal Mucosa / pathology*
  • Intestines / blood supply
  • Intestines / immunology*
  • Intravital Microscopy
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Microvessels / pathology*
  • Neutrophil Infiltration
  • Neutrophils / immunology
  • Neutrophils / pathology*
  • Salmonella Infections / immunology*
  • Salmonella typhimurium / immunology*
  • Transendothelial and Transepithelial Migration

Substances

  • Chemokine CXCL1
  • Chemokine CXCL2
  • Cxcl1 protein, mouse
  • Cxcl2 protein, mouse
  • Green Fluorescent Proteins