Time-lapse microscopy of macrophages during embryonic vascular development

Sarah Al-Roubaie, Jasmine H Hughes, Michael B Filla, Rusty Lansford, Stephanie Lehoux, Elizabeth A V Jones*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


BACKGROUND: Macrophages are present before the onset of blood flow, but very little is known about their function in vascular development. We have developed a technique to concurrently label both endothelial cells and macrophages for time-lapse microscopy using co-injection of fluorescently conjugated acetylated low-density lipoprotein (AcLDL) and phagocytic dye PKH26-PCL.

RESULTS: We characterize double-labeled cells to confirm specific labeling of macrophages. Double-labeled cells circulate, roll along the endothelium, and extravasate from vessels. Most observed macrophages are integrated into the vessel wall, showing an endothelial-like morphology. We used transgenic quail that express a fluorescent protein driven by the endothelial-specific promoter Tie1 in conjugation with the phagocytic dye to analyze these cells. Circulating PKH26-PCL-labeled cells are mostly Tie1-, but those which have integrated into the vessel wall are largely Tie1+. The endothelial-like phagocytic cells were generally stationary during normal vascular development. We, therefore, induced vascular remodeling and found that these cells could be recruited to sites of remodeling.

CONCLUSIONS: The active interaction of endothelial cells and macrophages support the hypothesis that these cells are involved in vascular remodeling. The presence of phagocytic endothelial-like cells suggests either a myeloid-origin to certain endothelial cells or that circulating endothelial cells/hematopoietic stem cells have phagocytic capacity.

Original languageEnglish
Pages (from-to)1423-31
Number of pages9
JournalDevelopmental Dynamics
Issue number9
Publication statusPublished - Sept 2012
Externally publishedYes


  • Animals
  • Blood Vessels/cytology
  • Coturnix/embryology
  • Embryo, Nonmammalian
  • Embryonic Development/physiology
  • Endothelium, Vascular/cytology
  • Fluorescent Dyes/pharmacology
  • Macrophages/cytology
  • Microscopy/methods
  • Organic Chemicals/pharmacology
  • Time-Lapse Imaging/methods

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