Induction of collagenase mRNA in lapine articular chondrocytes by synovial factors and interleukin-1

The cDNA probe H-9, originally constructed to recognize a portion of the mRNA for lapine synovial collagenase, also hybridized with a RNA of the same size (~2.0 kb) isolated from activated lapine articular chondrocytes. Primary, monolayer cultures of lapine articular chondrocytes did not contain detectable amounts of this RNA, nor did they secrete measurable amounts of collagenase into their culture media. Following exposure to synovial factors, the chondrocytes contained high levels of collagenase mRNA, while their conditioned media had considerable collagenolytic activity. Collagenase mRNA started to appear in chondrocytes 3-5 h after treatment with the synovial material. Maximum levels occurred after 12-24 h. Recombinant human interleukin-1 also induced the appearance of this mRNA. We conclude that chondrocyte collagenase is likely to be the same gene product as synovial collagenase, and that its regulation by lapine articular chondrocytes probably occurs at a pretranslational level.