Hanemaaijer R, Sorsa T, Konttinen Y T, Ding Y, Sutinen M, Visser H, van Hinsbergh V W, Helaakoski T, Kainulainen T, Rönkä H, Tschesche H, Salo T
Gaubius Laboratory TNO-PG, 2301 CE Leiden, The Netherlands.
J Biol Chem. 1997 Dec 12;272(50):31504-9. doi: 10.1074/jbc.272.50.31504.
Neutrophil collagenase (matrix metalloproteinase-8 or MMP-8) is regarded as being synthesized exclusively by polymorphonuclear neutrophils (PMN). However, in vivo MMP-8 expression was observed in mononuclear fibroblast-like cells in the rheumatoid synovial membrane. In addition, we detected MMP-8 mRNA expression in cultured rheumatoid synovial fibroblasts and human endothelial cells. Up-regulation of MMP-8 was observed after treatment of the cells with either tumor necrosis factor-alpha (10 ng/ml) or phorbol 12-myristate 13-acetate (10 nM). Western analysis showed a similar regulation at the protein level. The size of secreted MMP-8 was 50 kDa, which is about 30 kDa smaller than MMP-8 from PMN. Conditioned media from rheumatoid synovial fibroblasts contained both type I and II collagen degrading activity. However, degradation of type II collagen, but not that of type I collagen, was completely inhibited by 50 microM doxycycline, suggesting specific MMP-8 activity. In addition, doxycycline down-regulated MMP-8 induction, at both the mRNA and protein levels. Thus MMP-8 exerts markedly wider expression in human cells than had been thought previously, implying that PMN are not the only source of cartilage degrading activity at arthritic sites. The inhibition of both MMP-8 activity and synthesis by doxycycline provides an incentive for further studies on the clinical effects of doxycycline in the treatment of rheumatoid arthritis.
中性粒细胞胶原酶（基质金属蛋白酶-8或MMP-8）被认为仅由多形核中性粒细胞（PMN）合成。然而，在类风湿性滑膜的单核成纤维细胞样细胞中观察到了体内MMP-8的表达。此外，我们在培养的类风湿性滑膜成纤维细胞和人内皮细胞中检测到了MMP-8 mRNA的表达。在用肿瘤坏死因子-α（10 ng/ml）或佛波酯12-肉豆蔻酸酯13-乙酸酯（10 nM）处理细胞后，观察到MMP-8的上调。蛋白质印迹分析显示在蛋白质水平上有类似的调节。分泌的MMP-8大小为50 kDa，比PMN来源的MMP-8小约30 kDa。类风湿性滑膜成纤维细胞的条件培养基含有I型和II型胶原降解活性。然而，50 μM强力霉素完全抑制了II型胶原的降解，但未抑制I型胶原的降解，提示有特异性的MMP-8活性。此外强力霉素在mRNA和蛋白质水平下调MMP-8的诱导。因此，MMP-8在人类细胞中的表达比以前认为的要广泛得多，这意味着PMN不是关节炎部位软骨降解活性的唯一来源。强力霉素对MMP-8活性和合成的抑制为进一步研究强力霉素治疗类风湿性关节炎的临床效果提供了动力。
