Differential patterns of response to doxycycline and transforming growth factor beta1 in the down-regulation of collagenases in osteoarthritic and normal human chondrocytes.
OBJECTIVE
To investigate the ability of doxycycline, transforming growth factor beta1 (TGFbeta1), and phorbol myristate acetate (PMA) to modulate collagenase synthesis in osteoarthritic (OA) chondrocytes.


METHODS
Levels of fibroblast collagenase (matrix metalloproteinase 1 [MMP-1]), neutrophil collagenase (MMP-8), and collagenase 3 (MMP-13) proteins and messenger RNA (mRNA) were measured in chondrocytes isolated from involved and uninvolved areas of OA cartilage and from normal human chondrocytes, after treatment with doxycycline, TGFbeta1, and PMA.


RESULTS
Chondrocytes isolated from cartilage immediately adjacent to the OA lesion had, on average, 1.8-3.9-fold higher basal levels of MMP mRNA. These cells down-regulated collagenase proteins and mRNA upon incubation with TGFbeta1. In contrast, chondrocytes from areas located more distant from the macroscopic lesion increased MMP-13 mRNA, while MMP-1 and MMP-8 decreased after stimulation with TGFbeta1. Discoordinate regulation was observed after stimulation with PMA, with an increase in MMP-1 and MMP-8 but a decrease in MMP-13. Incubation of OA chondrocytes with doxycycline (1-10 microg/ml), at pharmacologically achievable levels, decreased levels of mRNA of all 3 collagenases, but not G3PDH. In addition, doxycycline inhibited the increase in mRNA for these enzymes in normal chondrocytes stimulated with tumor necrosis factor alpha.


CONCLUSIONS
These findings suggest that regulation of MMP-1, MMP-8, and MMP-13 in OA chondrocytes, although mediated by differing pathways, can be decreased by treatment with doxycycline at low concentrations. Our data provide a rationale for the use of doxycycline in the treatment of OA.
Shlopov
B V
BV
Department of Veterans Affairs Medical Center, and University of Tennessee, Memphis 38104, USA.
Smith
G N
GN
Cole
A A
AA
Hasty
K A
KA
D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015152:Blotting, Northern; D015153:Blotting, Western; D002273:Carcinogens / Q000494:pharmacology; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D017364:Collagenases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D004318:Doxycycline / Q000494:pharmacology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D020781:Matrix Metalloproteinase 1; D053509:Matrix Metalloproteinase 13; D020784:Matrix Metalloproteinase 8; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D013583:Synovial Membrane / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000032:analysis / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D002273:Carcinogens; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D017364:Collagenases; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13; D020784:Matrix Metalloproteinase 8; D020781:Matrix Metalloproteinase 1; D004318:Doxycycline; D013755:Tetradecanoylphorbol Acetate