Extracellular Protein Fibulin-7 and Its C-Terminal Fragment Have In Vivo Antiangiogenic Activity

Sci Rep. 2018 Dec 5;8(1):17654. doi: 10.1038/s41598-018-36182-w.

Abstract

Angiogenesis is crucial for tissue development and homeostasis; however, excessive angiogenesis can lead to diseases, including arthritis and cancer metastasis. Some antiangiogenic drugs are available, but side effects remain problematic. Thus, alternative angiogenesis inhibition strategies are needed. Fibulin-7 (Fbln7) is a newly discovered member of the fibulin protein family, a group of cell-secreted glycoproteins, that functions as a cell adhesion molecule and interacts with other extracellular matrix (ECM) proteins as well as cell receptors. We previously showed that a recombinant C-terminal Fbln7 fragment (Fbln7-C) inhibits tube formation by human umbilical vein endothelial cells (HUVECs) in vitro. In the present study, we examined the in vivo antiangiogenic activity of recombinant full-length Fbln7 (Fbln7-FL) and Fbln7-C proteins using a rat corneal angiogenesis model. We found that both Fbln7-FL and Fbln7-C inhibited neovascularization. Fbln7-C bound to vascular endothelial growth factor receptor 2 (VEGFR2), inhibiting VEGFR2 and ERK phosphorylation and resulting in reduced HUVEC motility. HUVEC attachment to Fbln7-C occurred through an interaction with integrin α5β1 and regulated changes in cellular morphology. These results suggest that Fbln7-C action may target neovascularization by altering cell/ECM associations. Therefore, Fbln7-C could have potential as a therapeutic agent for diseases associated with angiogenesis.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Angiogenesis Inhibitors / chemistry
  • Angiogenesis Inhibitors / metabolism*
  • Angiogenesis Inhibitors / pharmacology
  • Animals
  • Calcium-Binding Proteins / chemistry
  • Calcium-Binding Proteins / metabolism*
  • Calcium-Binding Proteins / pharmacology
  • Endothelial Cells / cytology
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism
  • Extracellular Matrix Proteins / chemistry
  • Extracellular Matrix Proteins / metabolism
  • Extracellular Matrix Proteins / pharmacology
  • Female
  • Human Umbilical Vein Endothelial Cells
  • Humans
  • Integrin alpha5beta1 / metabolism
  • Mice
  • Neovascularization, Physiologic* / drug effects
  • Phosphorylation / drug effects
  • Rats
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Recombinant Proteins / pharmacology
  • Signal Transduction / drug effects
  • Vascular Endothelial Growth Factor A / metabolism
  • Vascular Endothelial Growth Factor Receptor-2 / metabolism

Substances

  • Angiogenesis Inhibitors
  • Calcium-Binding Proteins
  • Extracellular Matrix Proteins
  • Fbln7 protein, mouse
  • Integrin alpha5beta1
  • Recombinant Proteins
  • Vascular Endothelial Growth Factor A
  • Vascular Endothelial Growth Factor Receptor-2