Increased matrix metalloproteinase-9 concentration and activity after stimulation with interleukin-17 in mouse airways
- 1Lung Pharmacology Group, Department of Respiratory Medicine and Allergology, Institute of Internal Medicine, Göteborg University, Gothenburg, Sweden
- 2Lung Disease Research Laboratories, CRC for Chronic Inflammatory Diseases, Department of Pharmacology, the University of Melbourne, Parkville, VIC 3010, Australia
- Correspondence to:
Dr O Prause
Lung Pharmacology Group, Department of Respiratory Medicine and Allergology, Institute of Internal Medicine, Göteborg University, 41346 Gothenburg, Sweden;
- Received 16 April 2003
- Accepted 12 November 2003
Background: The proteolytic enzyme matrix metalloproteinase (MMP)-9 can degrade structural compounds such as the extracellular matrix and the basement membrane in the airways and lungs. MMP-9 has therefore been implicated in remodelling of the airways and lungs during severe asthma and chronic obstructive pulmonary disease (COPD).
Methods: The effect of the T lymphocyte derived proinflammatory cytokine interleukin (IL)-17 on MMP-9 protein release and activity in the airways was studied in vivo and in vitro.
Results: In vivo, intranasal stimulation of mice with IL-17 induced the release of the precursor molecule proMMP-9 in bronchoalveolar lavage (BAL) fluid, associated with a pronounced local accumulation of neutrophils that stained positive for MMP-9. Stimulation with IL-17 also increased the concentration of free soluble MMP-9 that was proteolytically active as determined by a gelatinase substrate assay. The concentration of MMP-9 in BAL fluid had a strong positive correlation with the number of neutrophils; the amount of MMP-9 per neutrophil was not increased by IL-17 stimulation. In vitro, stimulation of mouse neutrophils with IL-17 did not increase the concentration of proMMP-9 in the conditioned medium.
Conclusion: Local stimulation with IL-17 increases the concentration of biologically active MMP-9 as well as its precursor molecule in mouse airways in vivo. This increase in proteolytic load is probably mainly due to an increased number of neutrophils and not to an increase in the release of MMP-9 from each neutrophil. These findings indicate a link between the T lymphocyte cytokine IL-17 and increased proteolytic load in the airways which may be relevant for chronic inflammatory airway diseases such as severe asthma and COPD.