Chondrocyte matrix metalloproteinase-8. Human articular chondrocytes express neutrophil collagenase.
This study confirms that normal human articular chondrocytes express neutrophil collagenase or matrix metalloproteinase-8 (MMP-8), a gene product previously thought to be expressed exclusively by neutrophil leukocytes. Both MMP-8 protein and mRNA were present in articular cartilages collected from normal human donors. Cartilage extracts were assayed by immunoblotting and by analysis of enzymatic activity on gelatin-substrate gels. Latent MMP-8 extracted from cartilage has a molecular mass of 55 kDa; active MMP-8 was identified at 46 and 42 kDa. In the absence of a reducing agent, MMP-8 migrated in a high molecular mass complex above 200 kDa. Northern blotting results demonstrated the expression of MMP-8 in chondrocytes, which could be up-regulated by stimulation with interleukin-1 beta. In addition, reverse transcription-polymerase chain reaction using nested primers and in situ hybridization revealed the presence of MMP-8 mRNA in chondrocytes. The presence of both MMP-8 protein and message in cartilage supports the concept that neutrophil collagenase could be the enzyme described as "aggrecanase".
Cole
A A
AA
Department of Biochemistry, Rush Medical College, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA.
Chubinskaya
S
S
Schumacher
B
B
Huch
K
K
Szabo
G
G
Yao
J
J
Mikecz
K
K
Hasty
K A
KA
Kuettner
K E
KE
D015152:Blotting, Northern; D002358:Cartilage, Articular / Q000166:cytology / Q000201:enzymology*; D002478:Cells, Cultured; D017364:Collagenases / Q000235:genetics / Q000378:metabolism*; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D017403:In Situ Hybridization; D020784:Matrix Metalloproteinase 8; D009504:Neutrophils / Q000201:enzymology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
D012333:RNA, Messenger; D010450:Endopeptidases; D017364:Collagenases; D020784:Matrix Metalloproteinase 8; C083641:aggrecanase