The Prox1-Vegfr3 feedback loop maintains the identity and the number of lymphatic endothelial cell progenitors

Genes Dev. 2014 Oct 1;28(19):2175-87. doi: 10.1101/gad.216226.113.


The mammalian lymphatic vasculature is important for returning fluids from the extracellular tissue milieu back to the blood circulation. We showed previously that Prox1 dosage is important for the development of the mammalian lymphatic vasculature. The lack of Prox1 activity results in the complete absence of lymphatic endothelial cells (LECs). In Prox1 heterozygous embryos, the number of LECs is reduced because of a decrease in the progenitor pool in the cardinal vein. This reduction is caused by some progenitor cells being unable to maintain Prox1 expression. In this study, we identified Vegfr3, the cognate receptor of the lymphangiogenic growth factor Vegfc, as a dosage-dependent, direct in vivo target of Prox1. Using various mouse models, we also determined that Vegfr3 regulates Prox1 by establishing a feedback loop necessary to maintain the identity of LEC progenitors and that Vegfc-mediated activation of Vegfr3 signaling is necessary to maintain Prox1 expression in LEC progenitors. We propose that this feedback loop is the main sensing mechanism controlling the number of LEC progenitors and, as a consequence, the number of budding LECs that will form the embryonic lymphatic vasculature.

Keywords: Prox1; Vegfr3; endothelial cell; lymphatics; mouse; progenitor.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Count
  • Embryo, Nonmammalian
  • Endothelial Cells / cytology*
  • Endothelial Cells / physiology*
  • Endothelial Progenitor Cells / cytology*
  • Endothelial Progenitor Cells / physiology*
  • Gene Expression Regulation
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism*
  • Lymphatic Vessels / cytology
  • Lymphatic Vessels / metabolism
  • Mice
  • Signal Transduction
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism*
  • Vascular Endothelial Growth Factor Receptor-3 / genetics
  • Vascular Endothelial Growth Factor Receptor-3 / metabolism*


  • Homeodomain Proteins
  • Tumor Suppressor Proteins
  • prospero-related homeobox 1 protein
  • Vascular Endothelial Growth Factor Receptor-3