Regulation of matrix metalloproteinase secretion by green tea catechins in a three-dimensional co-culture model of macrophages and gingival fibroblasts.
OBJECTIVE
Elevated levels of matrix metalloproteinases (MMPs) have been associated with the active phases of tissue and bone destruction in periodontitis, an inflammatory disease characterized by a significant breakdown of tooth support. In the present study, we used a three-dimensional (3D) co-culture model of macrophages and gingival fibroblasts to investigate the ability of a green tea extract and its major constituent epigallocatechin-3-gallate (EGCG) to regulate the secretion of MMP-3, -8, and -9.


METHODS
The 3D co-culture model was composed of gingival fibroblasts embedded in a type I collagen matrix overlaid with macrophages. Two arbitrary ratios were tested. The ratio composed of 1 macrophage to 10 fibroblasts was used to mimic a slightly inflamed periodontal site while the ratio composed of 10 macrophages to 1 fibroblast was used to mimic a severely inflamed periodontal site. The 3D co-culture model was pre-treated for 2h with either the green tea extract or EGCG. It was then stimulated with Aggregatibacter actinomycetemcomitans lipopolysaccharide (LPS). The model was also first stimulated with LPS for 2h and then incubated with the green tea extract or EGCG. The concentrations of secreted MMP-3, -8, and -9 were quantified by enzyme-linked immunoassays.


RESULTS
When the 3D co-culture model was stimulated with A. actinomycetemcomitans LPS, the 10:1 ratio of macrophages to gingival fibroblasts was associated with a highest secretion of MMP-3 and -9 and, to a lesser extent, MMP-8, than the 1:10 ratio. Non-cytotoxic concentrations of the green tea extract or EGCG reduced the basal secretion levels of all three MMPs. A 2-h treatment with the green tea extract or EGCG prior to the stimulation with LPS resulted in a dose-dependent decrease in MMP secretion, with MMP-9 showing the most significant decrease. A decrease in MMP secretion was also observed when the green tea extract or EGCG was added following a 2-h stimulation with LPS.


CONCLUSIONS
Our results suggested that green tea catechins, and more specifically EGCG, offer promising prospects for the development of a novel adjunctive treatment for periodontitis because of their ability to decrease the secretion of MMPs, which are important tissue-destructive enzymes produced by mucosal and immune cells.
Oral Ecology Research Group, Faculty of Dentistry, Université Laval, Quebec City, QC, Canada.
Marie-Pierre
MP
Morin
Oral Ecology Research Group, Faculty of Dentistry, Université Laval, Quebec City, QC, Canada. Electronic address: daniel.grenier@greb.ulaval.ca.
Daniel
D
Grenier
D016976:Aggregatibacter actinomycetemcomitans / Q000737:chemistry; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D018920:Coculture Techniques / Q000379:methods*; D024042:Collagen Type I / Q000737:chemistry; D005347:Fibroblasts / Q000378:metabolism*; D006801:Humans; D008070:Lipopolysaccharides / Q000302:isolation & purification / Q000494:pharmacology; D008264:Macrophages / Q000378:metabolism*; D019278:Matrix Metalloproteinase 3 / Q000187:drug effects / Q000378:metabolism; D020784:Matrix Metalloproteinase 8 / Q000187:drug effects / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000187:drug effects / Q000378:metabolism; D020782:Matrix Metalloproteinases / Q000187:drug effects* / Q000378:metabolism*; D010518:Periodontitis / Q000188:drug therapy; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D013662:Tea / Q000737:chemistry*; D020298:U937 Cells
D024042:Collagen Type I; D008070:Lipopolysaccharides; D010936:Plant Extracts; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate; D020782:Matrix Metalloproteinases; C511768:MMP3 protein, human; D019278:Matrix Metalloproteinase 3; C488762:MMP8 protein, human; D020784:Matrix Metalloproteinase 8; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9
Aggregatibacter actinomycetemcomitans; Catechin; Fibroblast; Green tea; Lipopolysaccharide; Macrophage; Matrix metalloproteinase; Periodontal disease; Polyphenol