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Matrix metalloproteinase-9 amplifies the immune response to Pseudomonas aeruginosa corneal infection

Sharon A McClellan1, Xi Huang, Ronald P Barrett

  • 1Department of Anatomy/Cell Biology, Wayne State University School of Medicine, 540 East Canfield Avenue, Detroit, Michigan 48201, USA.

Investigative Ophthalmology & Visual Science
|December 31, 2005
PubMed
Abstract

Insights

Matrix metalloproteinase-9 (MMP-9) exacerbates Pseudomonas aeruginosa keratitis by degrading collagen IV and increasing inflammatory signals. Inhibiting MMP-9 reduces corneal disease severity and immune cell infiltration.

Area of Science:

  • Ophthalmology
  • Microbiology
  • Immunology

Background:

  • Pseudomonas aeruginosa keratitis is a severe eye infection.
  • Matrix metalloproteinases (MMPs) are implicated in tissue damage during infection.

Purpose of the Study:

  • To investigate the role of MMPs, specifically MMP-9, in the pathogenesis of P. aeruginosa keratitis.

Main Methods:

  • Gene array and PCR to assess MMP expression in susceptible (B6) vs. resistant (BALB/c) mice.
  • Zymography, recombinant MMP-9, and MMP-9 knockout mice were used to evaluate MMP-9's enzymatic activity and effects.
  • Analysis of immune cell infiltration (Langerhans cells, neutrophils) and cytokine levels (IL-1beta, MIP-2).

Main Results:

  • MMP-9 expression and activity were significantly higher in infected corneas of susceptible mice.
  • MMP-9 enhanced corneal disease, while MMP-9 neutralization or absence reduced disease severity.
  • MMP-9 influenced immune cell infiltration and upregulated key inflammatory cytokines.

Conclusions:

  • MMP-9 plays a critical role in P. aeruginosa keratitis pathogenesis.
  • MMP-9 potentiates infection by degrading collagen IV and modulating immune responses.

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