IL-17A differentially regulates corneal vascular endothelial growth factor (VEGF)-A and soluble VEGF receptor 1 expression and promotes corneal angiogenesis after herpes simplex virus infection

J Immunol. 2012 Apr 1;188(7):3434-46. doi: 10.4049/jimmunol.1102602. Epub 2012 Feb 29.

Abstract

Ocular infection with HSV causes corneal neovascularization (CV), an essential step in the pathogenesis of the blinding immunoinflammatory lesion stromal keratitis. The infection results in IL-17A production, which contributes to CV in ways that together serve to shift the balance between corneal concentrations of vascular endothelial growth factor A (VEGF-A) and the soluble vascular endothelial growth factor receptor 1 molecule, which binds to VEGF-A and blocks its function (a so-called VEGF trap). Accordingly, animals lacking responses to IL-17A signaling, either because of IL-17 receptor A knockout or wild-type animals that received neutralizing mAb to IL-17A, had diminished CV, compared with controls. The procedures reduced VEGF-A protein levels but had no effect on the levels of soluble vascular endothelial growth factor receptor 1. Hence the VEGF trap was strengthened. IL-17A also caused increased CXCL1/KC synthesis, which attracts neutrophils to the inflammatory site. Neutrophils further influenced the extent of CV by acting as an additional source of VEGF-A, as did metalloproteinase enzymes that degrade the soluble receptor, inhibiting its VEGF-blocking activity. Our results indicate that suppressing the expression of IL-17A, or increasing the activity of the VEGF trap, represents a useful approach to inhibiting CV and the control of an ocular lesion that is an important cause of human blindness.

Publication types

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

MeSH terms

  • Animals
  • Chemokine CXCL1 / biosynthesis
  • Chemokine CXCL1 / genetics
  • Chemotaxis, Leukocyte / physiology
  • Cornea / metabolism
  • Corneal Neovascularization / etiology
  • Corneal Neovascularization / genetics
  • Corneal Neovascularization / physiopathology*
  • Cytokines / biosynthesis
  • Cytokines / genetics
  • Enzyme Induction
  • Fibroblasts / metabolism
  • Gene Expression Regulation
  • Interleukin-17 / deficiency
  • Interleukin-17 / genetics
  • Interleukin-17 / physiology*
  • Interleukin-6 / biosynthesis
  • Interleukin-6 / genetics
  • Keratitis, Herpetic / complications*
  • Matrix Metalloproteinases / biosynthesis
  • Matrix Metalloproteinases / genetics
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Neutrophils / physiology
  • Signal Transduction
  • Stromal Cells / metabolism
  • Vascular Endothelial Growth Factor A / biosynthesis*
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor Receptor-1 / biosynthesis*
  • Vascular Endothelial Growth Factor Receptor-1 / genetics

Substances

  • Chemokine CXCL1
  • Cxcl1 protein, mouse
  • Cytokines
  • Il17a protein, mouse
  • Interleukin-17
  • Interleukin-6
  • Vascular Endothelial Growth Factor A
  • vascular endothelial growth factor A, mouse
  • Vascular Endothelial Growth Factor Receptor-1
  • Matrix Metalloproteinases