POSTTRANSCRIPTIONAL REGULATION OF COLLAGENASE-1 GENE-EXPRESSION IN SYNOVIOCYTES BY ADENOSINE RECEPTOR STIMULATION

Objective. To characterize the transcriptional and posttranscriptional regulation of collagenase-1 by adenosine receptor stimulation in inte rleukin-l (IL-1)-stimulated fibroblast-like synoviocytes (FLS). Method s. FLS were stimulated with IL-I and either the nonselective adenosine agonist 5'-N-ethylcarboxamidoadenosine (NECA) or the adenylate cyclas e activator forskolin, Electrophoretic mobility shift assays were perf ormed to determine AP-1 and cAMP-responsive element binding protein (C REB) activation, Transcriptional activation was-determined by transfec ting HS68 dermal fibroblasts with a collagenase-chloramphenicol acetyl transferase construct, Finally, collagenase messenger RNA (mRNA) half- life was determined by activating cells in the presence of IL-1, IL-1 + NECA, or IL-1 + forskolin and culturing cells in the presence of act inomycin D. Results. NECA and forskolin had no effect on AP-1 activati on, c-jun or c-fos gene expression, or CREB phosphorylation, IL-1 mark edly increased collagenase promoter activity, and neither NECA nor for skolin blocked this action, Studies of mRNA half-life showed that both NECA and forskolin decreased the half-life of collagenase mRNA in IL- l-stimulated FLS and HS68 cells. Conclusion. The findings of this stud y demonstrate that NECA and forskolin decrease collagenase gene expres sion in FLS and dermal fibroblasts due to enhanced mRNA degradation.