Distinct vascular endothelial growth factor signals for lymphatic vessel enlargement and sprouting

J Exp Med. 2007 Jun 11;204(6):1431-40. doi: 10.1084/jem.20062642. Epub 2007 May 29.

Abstract

Lymphatic vessel growth, or lymphangiogenesis, is regulated by vascular endothelial growth factor-C (VEGF-C) and -D via VEGF receptor 3 (VEGFR-3). Recent studies suggest that VEGF, which does not bind to VEGFR-3, can also induce lymphangiogenesis through unknown mechanisms. To dissect the receptor pathway that triggers VEGFR-3-independent lymphangiogenesis, we used both transgenic and adenoviral overexpression of placenta growth factor (PlGF) and VEGF-E, which are specific activators of VEGFR-1 and -2, respectively. Unlike PlGF, VEGF-E induced circumferential lymphatic vessel hyperplasia, but essentially no new vessel sprouting, when transduced into mouse skin via adenoviral vectors. This effect was not inhibited by blocking VEGF-C and -D. Postnatal lymphatic hyperplasia, without increased density of lymphatic vessels, was also detected in transgenic mice expressing VEGF-E in the skin, but not in mice expressing PlGF. Surprisingly, VEGF-E induced lymphatic hyperplasia postnatally, and it did not rescue the loss of lymphatic vessels in transgenic embryos where VEGF-C and VEGF-D were blocked. Our data suggests that VEGFR-2 signals promote lymphatic vessel enlargement, but unlike in the blood vessels, are not involved in vessel sprouting to generate new lymphatic vessels in vivo.

Publication types

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

MeSH terms

  • Adenoviridae
  • Animals
  • Blotting, Western
  • Bromodeoxyuridine
  • DNA Primers
  • Genetic Vectors / genetics
  • Lymphangiogenesis / physiology*
  • Mice
  • Mice, Transgenic
  • Placenta Growth Factor
  • Pregnancy Proteins / metabolism
  • Receptors, Vascular Endothelial Growth Factor / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / physiology*
  • Vascular Endothelial Growth Factor A / metabolism*

Substances

  • DNA Primers
  • Pgf protein, mouse
  • Pregnancy Proteins
  • Vascular Endothelial Growth Factor A
  • Placenta Growth Factor
  • Receptors, Vascular Endothelial Growth Factor
  • Bromodeoxyuridine