Matrix metalloproteinase-9 activates TGF-β and stimulates fibroblast contraction of collagen gels.
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.
Mie University of Graduate School of Medicine, Tsu, Japan;
Tetsu
T
Kobayashi
WonKwang University Sanbon Medical Center, Seoul, Korea;
HuiJung
H
Kim
University of Nebraska Medical Center, Omaha, Nebraska;
Xiangde
X
Liu
Tohoku University Graduate School of Medicine, Sendai, Japan;
Hisatoshi
H
Sugiura
Teikyo University School of Medicine, Kawasaki, Japan;
Tadashi
T
Kohyama
Department of Pulmonary and Critical Care, Beijing Shijitan Hospital, Capital Medical University, Beijing, China;
Qiuhong
Q
Fang
West China School of Medicine, Sichuan, China;
Fu-Qiang
FQ
Wen
Nippon Medical School, Tokyo, Japan;
Shinji
S
Abe
Affiliated Hospital of Hebei United University, Hebei Province, China;
Xingqi
X
Wang
Washington University School of Medicine, St. Louis, Missouri.
Jeffrey J
JJ
Atkinson
Washington University School of Medicine, St. Louis, Missouri.
James M
JM
Shipley
Washington University School of Medicine, St. Louis, Missouri.
Robert M
RM
Senior
University of Nebraska Medical Center, Omaha, Nebraska; srennard@unmc.edu.
Stephen I
SI
Rennard
D000818:Animals; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism*; D004151:Dipeptides / Q000494:pharmacology; D005347:Fibroblasts / Q000201:enzymology*; D005782:Gels; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000502:physiology*; D061965:Matrix Metalloproteinase Inhibitors / Q000494:pharmacology; D051379:Mice; D057507:Mice, 129 Strain; D018345:Mice, Knockout; D051381:Rats; D015398:Signal Transduction; D051900:Smad3 Protein / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*
D004151:Dipeptides; D005782:Gels; D061965:Matrix Metalloproteinase Inhibitors; C078131:N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide; C497790:SMAD3 protein, human; D051900:Smad3 Protein; C508960:TGFB1 protein, human; D053773:Transforming Growth Factor beta1; D003094:Collagen; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9
lung; repair; transforming growth factor-β