EGF-like-domain-7 is required for VEGF-induced Akt/ERK activation and vascular tube formation in an ex vivo angiogenesis assay

PLoS One. 2014 Mar 19;9(3):e91849. doi: 10.1371/journal.pone.0091849. eCollection 2014.

Abstract

EGFL7 is a secreted angiogenic factor, which in contrast to the well-known secreted angiogenic molecules VEGF and FGF-2, is almost exclusively expressed by endothelial cells and may act in an autocrine fashion. Prior studies have shown EGFL7 to mediate its angiogenic effects by interfering with the Notch pathway and/or via the intronic miR126. Less is known about its effects on VEGF signaling. We wanted to investigate the role of epidermal growth factor-like domain 7 (EGFL7) in VEGF-driven angiogenesis using an ex vivo Matrigel-embedded mouse eye cup assay and siRNA mediated knockdown of EGFL7 by siRNA. Our results suggested that VEGF-induced vascular tube formation was significantly impaired after siRNA downregulation of EGFL7. In addition, knockdown of EGFL7 suppressed VEGF upregulation of phospho-Akt and phospho-Erk(1/2) in endothelial cells, but did not alter VEGFR phosphorylation and neuropilin-1 protein expression or miR126 expression. Thus, in conclusion, EGFL7 is required for VEGF upregulation of the Akt/Erk (1/2) pathway during angiogenesis, and may represent a new therapeutic target in diseases of pathological neovascularization.

Publication types

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

MeSH terms

  • Animals
  • Biological Assay*
  • Calcium-Binding Proteins
  • EGF Family of Proteins
  • Endothelial Cells / drug effects
  • Endothelial Cells / enzymology
  • Enzyme Activation / drug effects
  • Extracellular Signal-Regulated MAP Kinases / metabolism*
  • Gene Knockdown Techniques
  • In Vitro Techniques*
  • Mice, Inbred C57BL
  • Neovascularization, Physiologic / drug effects*
  • Neuropilin-1 / metabolism
  • Phosphorylation / drug effects
  • Proteins / metabolism*
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Vascular Endothelial Growth Factor A / pharmacology*
  • Vascular Endothelial Growth Factor Receptor-2 / metabolism

Substances

  • Calcium-Binding Proteins
  • EGF Family of Proteins
  • Egfl7 protein, mouse
  • Proteins
  • Vascular Endothelial Growth Factor A
  • Neuropilin-1
  • Vascular Endothelial Growth Factor Receptor-2
  • Proto-Oncogene Proteins c-akt
  • Extracellular Signal-Regulated MAP Kinases