Abstract
Proteinases play a pivotal role in wound healing by regulating cell-matrix interactions and availability of bioactive molecules. The role of matrix metalloproteinase-13 (MMP-13) in granulation tissue growth was studied in subcutaneously implanted viscose cellulose sponge in MMP-13 knockout (Mmp13(-/-)) and wild type (WT) mice. The tissue samples were harvested at time points day 7, 14 and 21 and subjected to histological analysis and gene expression profiling. Granulation tissue growth was significantly reduced (42%) at day 21 in Mmp13(-/-) mice. Granulation tissue in Mmp13(-/-) mice showed delayed organization of myofibroblasts, increased microvascular density at day 14, and virtual absence of large vessels at day 21. Gene expression profiling identified differentially expressed genes in Mmp13(-/-) mouse granulation tissue involved in biological functions including inflammatory response, angiogenesis, cellular movement, cellular growth and proliferation and proteolysis. Among genes linked to angiogenesis, Adamts4 and Npy were significantly upregulated in early granulation tissue in Mmp13(-/-) mice, and a set of genes involved in leukocyte motility including Il6 were systematically downregulated at day 14. The expression of Pdgfd was downregulated in Mmp13(-/-) granulation tissue in all time points. The expression of matrix metalloproteinases Mmp2, Mmp3, Mmp9 was also significantly downregulated in granulation tissue of Mmp13(-/-) mice compared to WT mice. Mmp13(-/-) mouse skin fibroblasts displayed altered cell morphology and impaired ability to contract collagen gel and decreased production of MMP-2. These results provide evidence for an important role for MMP-13 in wound healing by coordinating cellular activities important in the growth and maturation of granulation tissue, including myofibroblast function, inflammation, angiogenesis, and proteolysis.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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ADAM Proteins / genetics
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ADAM Proteins / metabolism
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ADAMTS4 Protein
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Animals
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Cell Differentiation / genetics
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Cell Survival / genetics
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Collagen / metabolism
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Down-Regulation / genetics
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Gels
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Gene Expression Profiling*
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Gene Regulatory Networks / genetics
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Granulation Tissue / blood supply
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Granulation Tissue / pathology*
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Inflammation / genetics*
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Inflammation / pathology
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Male
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Matrix Metalloproteinase 13 / genetics
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Matrix Metalloproteinase 13 / metabolism*
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Matrix Metalloproteinase 2 / metabolism
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Mice
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Myofibroblasts / pathology
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Neovascularization, Pathologic / enzymology
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Neovascularization, Pathologic / genetics
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Neovascularization, Pathologic / pathology
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Neuropeptide Y / genetics
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Neuropeptide Y / metabolism
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Procollagen N-Endopeptidase / genetics
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Procollagen N-Endopeptidase / metabolism
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Proteolysis*
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Skin / pathology
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Time Factors
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Wound Healing / genetics*
Substances
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Gels
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Neuropeptide Y
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Collagen
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ADAM Proteins
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Matrix Metalloproteinase 13
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Mmp13 protein, mouse
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Procollagen N-Endopeptidase
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Matrix Metalloproteinase 2
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ADAMTS4 Protein
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Adamts4 protein, mouse
Grants and funding
The study has been supported by grants from the Academy of Finland (project 137687), Turku University Hospital (project 13336), the Sigrid Jusélius Foundation, the Cancer Research Foundation of Finland, and by personal grants (to M. Toriseva) from Orion-Farmos Research Foundation, K. Albin Johansson's Foundation, Southwestern Finnish Cancer Foundation, Maud Kuistila's Memory Foundation, Paulo Foundation and Finnish Cultural Foundation. Generation of the Mmp13−/− mice and backcrossing into WT mice was supported by grants from the U.S. National Institutes of Health to S.M. Krane. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.