Nieminen Riina, Vuolteenaho Katriina, Riutta Asko, Kankaanranta Hannu, van der Kraan Peter M, Moilanen Teemu, Moilanen Eeva
The Immunopharmacology Research Group, Medical School, University of Tampere and Research Unit, Tampere University Hospital, Tampere, Finland.
Eur J Pharmacol. 2008 Jun 10;587(1-3):309-16. doi: 10.1016/j.ejphar.2008.03.016. Epub 2008 Mar 29.
Cyclooxygenase-2 (COX-2) is expressed in rheumatoid and osteoarthritic cartilage and produces pro-inflammatory prostanoids in the joint. In the present study, we investigated the effects of disease modifying anti-rheumatic drugs on COX-2 expression in chondrocytes. Unlike the other tested drugs, aurothiomalate was found to inhibit COX-2 expression in chondrocytes. In the further studies, effects and mechanisms of action of aurothiomalate were investigated in more detail. Aurothiomalate inhibited IL-1beta-induced COX-2 protein expression and PGE(2) production in chondrocytes in a dose-dependent manner. Because aurothiomalate did not alter IL-1beta-induced mRNA levels when measured 0-3 h after addition of IL-1beta, its effects on COX-2 mRNA degradation were tested by Actinomycin D assay. The half-life of COX-2 mRNA was reduced from 3 h to less than 1.5 h in aurothiomalate-treated cells. The 3'-untranslated region (3'-UTR) of COX-2 mRNA contains an ARE element which has been shown to bind mRNA stabilizing factor HuR. Interestingly, aurothiomalate inhibited HuR expression which may explain its destabilizing effect on COX-2 mRNA. Aurothiomalate reduced COX-2 expression and PGE(2) production also in human cartilage at drug concentrations which have been measured in serum and synovial fluid during treatment with aurothiomalate. The results show that aurothiomalate reduces COX-2 expression and PGE(2) production in chondrocyte cultures and in human cartilage. The action is likely mediated by enhanced COX-2 mRNA degradation possibly through a mechanism related to reduced expression of HuR. The results provide a novel mechanism of action for aurothiomalate which may be important in the treatment of arthritis.
环氧化酶-2（COX-2）在类风湿性和骨关节炎性软骨中表达，并在关节中产生促炎前列腺素。在本研究中，我们调查了改善病情抗风湿药对软骨细胞中COX-2表达的影响。与其他受试药物不同，发现金硫代苹果酸可抑制软骨细胞中COX-2的表达。在进一步的研究中，对金硫代苹果酸的作用效果及作用机制进行了更详细的研究。金硫代苹果酸以剂量依赖的方式抑制白细胞介素-1β（IL-1β）诱导的软骨细胞中COX-2蛋白表达和前列腺素E2（PGE2）的产生。由于在添加IL-1β后0至3小时测量时，金硫代苹果酸并未改变IL-1β诱导的mRNA水平，因此通过放线菌素D试验检测了其对COX-2 mRNA降解的影响。在金硫代苹果酸处理的细胞中，COX-2 mRNA的半衰期从3小时缩短至不到1.5小时。COX-2 mRNA的3'非翻译区（3'-UTR）包含一个富含AU元件（ARE），该元件已被证明可结合mRNA稳定因子HuR。有趣的是，金硫代苹果酸抑制HuR的表达，这可能解释了其对COX-2 mRNA的去稳定作用。在金硫代苹果酸治疗期间血清和滑液中测得的药物浓度下，金硫代苹果酸也降低了人软骨中COX-2的表达和PGE2的产生。结果表明，金硫代苹果酸可降低软骨细胞培养物和人软骨中COX-2的表达和PGE2的产生。其作用可能是通过增强COX-2 mRNA降解介导的，可能是通过与HuR表达降低相关的机制。这些结果为金硫代苹果酸提供了一种新的作用机制，这可能在关节炎治疗中具有重要意义。
