Junctional adhesion molecule-A regulates vascular endothelial growth factor receptor-2 signaling-dependent mouse corneal wound healing

PLoS One. 2013 May 8;8(5):e63674. doi: 10.1371/journal.pone.0063674. Print 2013.

Abstract

Inflammation and angiogenesis are integral parts of wound healing. However, excessive and persistent wound-induced inflammation and angiogenesis in an avascular tissue such as the cornea may be associated with scarring and visual impairment. Junctional adhesion molecule A (Jam-A) is a tight junction protein that regulates leukocyte transmigration as well as fibroblast growth factor-2 (FGF-2)-induced angiogenesis. However its function in wound-induced inflammation and angiogenesis is still unknown. In this study, we report spontaneous corneal opacity in Jam-A deficient mice associated with inflammation, angiogenesis and the presence of myofibroblasts. Since wounds and/or corneal infections cause corneal opacities, we tested the role of Jam-A in wound-induced inflammation, angiogenesis and scarring by subjecting Jam-A deficient mice to full thickness corneal wounding. Analysis of these wounds demonstrated increased inflammation, angiogenesis, and increased number of myofibroblasts thereby indicating that Jam-A regulates the wound-healing response by controlling wound-induced inflammation, angiogenesis and scarring in the cornea. These effects were not due to inflammation alone since the inflammation-induced wound-healing response in Jam-A deficient mice was similar to wild type mice. In order to determine the molecular mechanism associated with the observed aberrant corneal wound healing in Jam-A deficient mice, we assessed the expression of the components of vascular endothelial growth factor A (VEGF-A)/vascular endothelial growth factor receptor- 2(VEGFR-2) signaling pathway. Interestingly, we observed increased levels of VEGF-A mRNA in Jam-A deficient eyes. We also observed nuclear localization of phosphorylated SMAD3 (pSMAD3) indicative of TGFβ pathway activation in the Jam-A deficient eyes. Furthermore the increased wound-induced corneal inflammation, angiogenesis, and scarring in Jam-A deficient mice was attenuated by treatment with DC101, an anti-vascular endothelial growth factor receptor-2 (VEGFR-2) antibody. Our results suggest that in the absence of Jam-A, the VEGF-A/VEGFR-2 pathway is upregulated, thereby augmenting wound induced corneal inflammation, angiogenesis, and myofibroblast accumulation leading to scarring.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antibodies, Monoclonal
  • Cell Adhesion Molecules / genetics
  • Cell Adhesion Molecules / metabolism*
  • Corneal Injuries*
  • Corneal Opacity / etiology
  • Corneal Opacity / genetics*
  • DNA Primers / genetics
  • Fluorescent Antibody Technique
  • Immunohistochemistry
  • Inflammation / etiology
  • Inflammation / genetics*
  • Mice
  • Mice, Knockout
  • Neovascularization, Pathologic / etiology
  • Neovascularization, Pathologic / physiopathology*
  • Real-Time Polymerase Chain Reaction
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / metabolism*
  • Signal Transduction / physiology
  • Vascular Endothelial Growth Factor Receptor-2 / metabolism
  • Wound Healing / physiology*

Substances

  • Antibodies, Monoclonal
  • Cell Adhesion Molecules
  • DNA Primers
  • F11r protein, mouse
  • Receptors, Cell Surface
  • Vascular Endothelial Growth Factor Receptor-2