Arhgef15 promotes retinal angiogenesis by mediating VEGF-induced Cdc42 activation and potentiating RhoJ inactivation in endothelial cells

PLoS One. 2012;7(9):e45858. doi: 10.1371/journal.pone.0045858. Epub 2012 Sep 21.

Abstract

Background: Drugs inhibiting vascular endothelial growth factor (VEGF) signaling are globally administered to suppress deregulated angiogenesis in a variety of eye diseases. However, anti-VEGF therapy potentially affects the normal functions of retinal neurons and glias which constitutively express VEGF receptor 2. Thus, it is desirable to identify novel drug targets which are exclusively expressed in endothelial cells (ECs). Here we attempted to identify an EC-specific Rho guanine nucleotide exchange factor (GEF) and evaluate its role in retinal angiogenesis.

Methodology/principal findings: By exploiting fluorescence-activated cell sorting and microarray analyses in conjunction with in silico bioinformatics analyses, we comprehensively identified endothelial genes in angiogenic retinal vessels of postnatal mice. Of 9 RhoGEFs which were highly expressed in retinal ECs, we show that Arhgef15 acted as an EC-specific GEF to mediate VEGF-induced Cdc42 activation and potentiated RhoJ inactivation, thereby promoting actin polymerization and cell motility. Disruption of the Arhgef15 gene led to delayed extension of vascular networks and subsequent reduction of total vessel areas in postnatal mouse retinas.

Conclusions/significance: Our study provides information useful to the development of new means of selectively manipulating angiogenesis without affecting homeostasis in un-targeted tissues; not only in eyes but also in various disease settings such as cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Animals
  • Cell Movement*
  • Cells, Cultured
  • Female
  • Gene Expression Profiling
  • Gene Knockdown Techniques
  • Guanine Nucleotide Exchange Factors / genetics
  • Guanine Nucleotide Exchange Factors / metabolism
  • Guanine Nucleotide Exchange Factors / physiology*
  • Human Umbilical Vein Endothelial Cells / metabolism*
  • Human Umbilical Vein Endothelial Cells / physiology
  • Humans
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Neovascularization, Physiologic
  • Oligonucleotide Array Sequence Analysis
  • Protein Multimerization
  • RNA Interference
  • Retina / cytology
  • Retina / metabolism
  • Retinal Vessels / physiology
  • Vascular Endothelial Growth Factor A / physiology*
  • cdc42 GTP-Binding Protein / metabolism*
  • rho GTP-Binding Proteins / metabolism*

Substances

  • Actins
  • Arhgef15 protein, human
  • Guanine Nucleotide Exchange Factors
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • RHOJ protein, human
  • cdc42 GTP-Binding Protein
  • rho GTP-Binding Proteins

Grant support

This work was supported by the ‘Global Center of Excellence for Education and Research on Signal Transduction Medicine in the Coming Generation’ and ‘Grants-in-Aid for Young Scientists’ (22689046) from the Ministry of Education, Culture, Sports, Science and Technology, Japan, and ‘Exploratory Research, Feasibility Study Stage, A-STEP’ (AS231Z03014G) from the Japan Science and Technology Agency. AU is supported by the Takeda Science Foundation, Mitsubishi Pharma Research Foundation, Inamori Foundation, Charitable Trust Fund for Ophthalmic Research in Commemoration of Santen Pharmaceutical’s Founder, and Mishima Saiichi Commemoration Ophthalmology Study Research Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.