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Activation of corneal fibroblast-derived matrix metalloproteinase-2 by tryptase

Kazutaka Yamamoto1, Naoki Kumagai, Ken Fukuda

  • 1Department of Biomolecular Recognition and Ophthalmology, Yamaguchi University School of Medicine, Ube City, Yamaguchi, Japan.

Current Eye Research
|April 11, 2006
PubMed
Abstract

Insights

Tryptase activates matrix metalloproteinase (MMP)-2 released by corneal fibroblasts. This cell-dependent activation may explain the presence of active MMP-2 in vernal keratoconjunctivitis tear fluid.

Area of Science:

  • Ophthalmology
  • Cell Biology
  • Biochemistry

Background:

  • Vernal keratoconjunctivitis (VKC) is characterized by active matrix metalloproteinase (MMP)-2 and elevated tryptase in tear fluid.
  • Tryptase is not known to activate purified MMP-2.

Purpose of the Study:

  • To investigate if tryptase activates MMP-2 in the presence of cultured human corneal fibroblasts.
  • To elucidate the mechanism of MMP-2 activation in VKC.

Main Methods:

  • Human corneal fibroblasts were cultured with or without tryptase.
  • MMP-2 activation was assessed using gelatin zymography.

Main Results:

  • Exogenous tryptase activated MMP-2 released by corneal fibroblasts.
  • Activation was cell-dependent and not mediated by protease-activated receptor 2 or the plasmin-plasminogen system.
  • Tissue inhibitor of metalloproteinase (TIMP)-2, but not TIMP-1, inhibited the tryptase-induced MMP-2 activation.

Conclusions:

  • Tryptase activates MMP-2 released from corneal fibroblasts in a cell-dependent manner.
  • This mechanism may contribute to the elevated levels of active MMP-2 observed in VKC tear fluid.

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