Collagen degradation by interleukin-1beta-stimulated gingival fibroblasts is accompanied by release and activation of multiple matrix metalloproteinases and cysteine proteinases.
OBJECTIVE
Several collagenolytic matrix metalloproteinases (MMPs) have recently been identified in gingival fibroblasts, while secreted cysteine proteinases could also participate in connective tissue destruction in periodontitis. To clarify their involvement, we examined enzyme release during collagen breakdown by cultured cytokine-stimulated fibroblasts.


METHODS
Gingival fibroblasts were derived from four chronic periodontitis patients and cultured on collagen gels in serum-free medium for 1-4 days. Collagenolysis was measured by hydroxyproline release into the medium. Proteinases were assessed by electrophoresis and immunoblotting.


RESULTS
Adding interleukin-1beta resulted in progressive gel breakdown. This was associated particularly with a shift in MMP-1 band position from proenzyme to active enzyme and the appearance of active as well as proenzyme forms of cathepsin B. There was also partial processing of pro-MMP-13 and increased immunoreactivity for active cathepsin L. In addition, both pro-forms and active forms of MMP-8, membrane-type-1-MMP and MMP-2 were present in control and treated cultures.


CONCLUSIONS
Fibroblast MMP-1 was most likely responsible for collagen dissolution in the culture model, while cathepsin B may have been part of an activation pathway. All studied proteinases contribute to extracellular matrix destruction in inflamed gingival tissue, where they probably activate each other in proteolytic cascades.
Cox
S W
SW
Department of Periodontology, Guy's, King's and St Thomas' Dental Institute, King's College London, UK. stephen.cox@kcl.ac.uk
Eley
B M
BM
Kiili
M
M
Asikainen
A
A
Tervahartiala
T
T
Sorsa
T
T
D000328:Adult; D015153:Blotting, Western; D002401:Cathepsin B / Q000378:metabolism; D024042:Collagen Type I / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology; D005881:Gingiva / Q000166:cytology / Q000201:enzymology*; D006801:Humans; D006909:Hydroxyproline / Q000378:metabolism; D007375:Interleukin-1 / Q000494:pharmacology; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D008875:Middle Aged; D010518:Periodontitis / Q000201:enzymology*
D024042:Collagen Type I; D007375:Interleukin-1; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; D020782:Matrix Metalloproteinases; D006909:Hydroxyproline