REGULATION OF RAT INTERSTITIAL COLLAGENASE GENE-EXPRESSION IN GROWTH CARTILAGE AND CHONDROCYTES BY VITAMIN-D-3, INTERLEUKIN-1-BETA, AND OKADAIC ACID

Citation
Rm. Grumbles et al., REGULATION OF RAT INTERSTITIAL COLLAGENASE GENE-EXPRESSION IN GROWTH CARTILAGE AND CHONDROCYTES BY VITAMIN-D-3, INTERLEUKIN-1-BETA, AND OKADAIC ACID, Journal of cellular biochemistry, 63(4), 1996, pp. 395-409
Citations number
56
Categorie Soggetti
Biology,"Cell Biology
ISSN journal
07302312
Volume
63
Issue
4
Year of publication
1996
Pages
395 - 409
Database
ISI
SICI code
0730-2312(1996)63:4<395:RORICG>2.0.ZU;2-5
Abstract
The interstitial collagenase produced by the rat growth plate chondroc ytes is the homologue of the human collagenase-3, or matrix metallopro teinase-13. This enzyme is responsible for the loss of collagen during hypertrophy of chondrocytes and for the degradation of transverse sep ta in long bone growth. Rachitic rats (42 days, male Sprague-Dawley) h ad an 8-fold higher level of collagenase mRNA in the hypertrophic vers us proliferative zone of growth plate cartilage. Intramuscular injecti on of 1,25-dihydroxyvitamin D-3 (1,25-(OH)(2)D-3; 1.0 mu g/kg body wei ght) in rachitic rats increased collagenase mRNA another 1.5-fold in t he hypertrophic zone. The regulation of collagenase gene by 1,25-(OH)( 2)D-3 and interleukin (IL)-1 beta in cultured proliferative chondrocyt es was studied by means of steady-state mRNA and half-life determinati on of mRNA using the transcriptional inhibitor actinomycin D, and nucl ear run-on transcription analyses. Treatment of cells with 1,25-(OH)(2 )D-3 (10(-6) M) and IL-1 beta (2 ng/ml) increased collagenase mRNA 8- and 13-fold, respectively. Additionally, the collagenase mRNA half-lif e was increased by 1,25-(OH)(2)D-3 and IL-1 beta. In the presence of a protein kinase C inhibitor, staurosporine, 1,25-(OH)(2)D-3 induction of collagenase mRNA was blocked. Here the addition of phorbol 12-myris ate 13-acetate (PMA) to activate protein kinase C increased collagenas e mRNA 10-fold. However, in the presence of staurosporine (50 nM), PMA induction was blocked, whereas IL-1 beta was not. IL-1 beta is known to activate several phosphorylation pathways. Okadaic acid (500 nM), a protein phosphatase inhibitor, increased the relative collagenase mRN A abundance 10-fold. The rate of the rat collagenase gene transcriptio n in nuclei was increased with 1,25-(OH)(2)D-3, IL-1 beta and okadaic acid. In separate experiments, the collagenase promoter was ligated to a reporter plasmid and the plasmid was transfected into chondrocytes. The results showed that 1,25-(OH)(2)D-3, IL-1 beta, and PMA increased reporter activity 2.5-, 2.8-, and 3.27-fold, respectively. Thus, ther e are multiple nuclear and cytoplasmic mechanisms by which cartilage m odulators regulate rat interstitial collagenase gene expression. (C) 1 996 Wiley-Liss, Inc.