Matrix metalloproteinase-9 activates TGF-β and stimulates fibroblast contraction of collagen gels

Tetsu Kobayashi, Hui Jung Kim, Xiangde Liu, Hisatoshi Sugiura, Tadashi Kohyama, Qiuhong Fang, Fu Qiang Wen, Shinji Abe, Xingqi Wang, Jeffrey J. Atkinson, James M. Shipley, Robert M. Senior, Stephen I. Rennard

Research output: Contribution to journalArticlepeer-review

161 Scopus citations


Matrix metalloproteinase-9 (MMP-9) is a matrix-degrading enzyme implicated in many biological processes, including inflammation. It is produced by many cells, including fibroblasts. When cultured in three-dimensional (3D) collagen gels, fibroblasts contract the surrounding matrix, a function that is thought to model the contraction that characterizes both normal wound repair and fibrosis. The current study was designed to evaluate the role of endogenously produced MMP-9 in fibroblast contraction of 3D collagen gels. Fibroblasts from mice lacking expression of MMP-9 and human lung fibroblasts (HFL-1) transfected with MMP-9 small-interfering RNA (siRNA) were used. Fibroblasts were cast into type I collagen gels and floated in culture medium with or without transforming growth factor (TGF)-β1 for 5 days. Gel size was determined daily using an image analysis system. Gels made from MMP-9 siRNA-treated human fibroblasts contracted less than control fibroblasts, as did fibroblasts incubated with a nonspecific MMP inhibitor. Similarly, fibroblasts cultured from MMP-9-deficient mice contracted gels less than did fibroblasts from control mice. Transfection of the MMP-9-deficient murine fibroblasts with a vector expressing murine MMP-9 restored contractile activity to MMP-9-deficient fibroblasts. Inhibition of MMP-9 reduced active TGF-β1 and reduced several TGF-β1-driven responses, including activity of a Smad3 reporter gene and production of fibronectin. Because TGF-β1 also drives fibroblast gel contraction, this suggests the mechanism for MMP-9 regulation of contraction is through the generation of active TGF-β1. This study provides direct evidence that endogenously produced MMP-9 has a role in regulation of tissue contraction of 3D collagen gels mediated by fibroblasts.

Original languageEnglish (US)
Pages (from-to)L1006-L1015
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Issue number11
StatePublished - Jun 1 2014


  • Lung
  • Repair
  • Transforming growth factor-β

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology


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