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Matrix metalloproteinases induction by pseudomonal virulence factors and inflammatory cytokines in vitro

S Miyajima1, T Akaike, K Matsumoto

  • 1Department of Microbiology, Kumamoto University School of Medicine, Kumamoto 860-0811, Japan.

Microbial Pathogenesis
|December 19, 2001
PubMed

Insights

Pseudomonas aeruginosa infection causes corneal damage by increasing matrix metalloproteinases (MMPs) through bacterial factors and inflammation. These MMPs are activated by pseudomonal elastase, leading to corneal destruction.

Area of Science:

  • Ophthalmology
  • Microbiology
  • Cell Biology

Background:

  • Pseudomonas aeruginosa is a major cause of bacterial keratitis.
  • Matrix metalloproteinases (MMPs) play a role in tissue degradation during corneal infections.

Purpose of the Study:

  • To investigate the role of Pseudomonas aeruginosa virulence factors and inflammatory cytokines in inducing and activating MMPs in the cornea.
  • To elucidate the mechanisms of corneal destruction in pseudomonal keratitis.

Main Methods:

  • In vivo studies using rabbit corneas infected with P. aeruginosa.
  • In vitro studies using rabbit corneal fibroblasts and human fibrosarcoma cells.
  • Techniques included reverse transcriptase-polymerase chain reaction (RT-PCR), zymography, and immunoblotting.

Main Results:

  • P. aeruginosa infection induced corneal ulcers and upregulated MMPs, especially MMP-9.
  • Pseudomonal elastase caused significant damage and activated MMP-2 and MMP-9.
  • Proinflammatory cytokines (TNF-alpha, IL-1beta) augmented MMP-9 expression.

Conclusions:

  • Corneal destruction in P. aeruginosa keratitis is mediated by enhanced MMP expression and activation.
  • Pseudomonal exoproteases and inflammatory cytokines stimulate corneal cells to produce MMPs.
  • Pseudomonal elastase is a key factor in the proteolytic activation of MMPs, contributing to tissue damage.

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