Lung alveolar epithelial cells synthesize interstitial collagenase and gelatinases A and B in vitro

Annie Pardo*, Karen Ridge, Bruce Uhal, J. Iasha Sznajder, Moisés Selman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Type II pneumocytes are multifunctional alveolar epithelial cells that play a major role in the maintenance of lung structure and function. Recent evidence supports that these cells can synthesize a variety of extracellular matrix components in vitro, suggesting an active participation in connective tissue remodeling. However, their possible role in extracellular matrix degradation is unknown. In this study the production of matrix metalloproteinases (MMPs) was examined in primary cultures of rat alveolar type II pneumocytes after 2 and 7 days in culture. Under basal conditions, at bed periods type II cells expressed interstitial collagenase mRNA. The immunoreactive protein was detected both in the cells and in conditioned media, and collagenolytic activity was revealed after trypsin activation. Gelatinolytic activity was detected by zymography showing a relative molecular mass of ~72 and 92 kDa (gelatinases A and B). Phorbol treatment increased collagenase and gelatinase activities. In addition, three alveolar epithelial cell lines were analysed for MMP production: MLE-12 (mice), L2 (rat), and A549 (human). The cell lines A549 and MLE-12 revealed collagenase and gelatinase A and B activities whereas the L2 cell line only exhibited gelatinase A activity, even after PMA induction. These findings demonstrate that alveolar epithelial cells synthesize in vitro several MMPs that confer on them the ability to degrade extracellular matrix and basement membrane components, a capacity of considerable importance, for the remodeling of the stromal/epithelial interface.

Original languageEnglish (US)
Pages (from-to)901-910
Number of pages10
JournalInternational Journal of Biochemistry and Cell Biology
Issue number6
StatePublished - Jun 1997


  • Collagenase
  • Extracellular matrix
  • Gelatinase
  • Type II pneumocytes

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology


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