Phenyl N-tert-butylnitrone down-regulates interleukin-1β-stimulated matrix metalloproteinase-13 gene expression in human chondrocytes:: Suppression of c-jun NH2-terminal kinase, p38-mitogen-activated protein kinase and activating protein-1
Phenyl N-tert-butylnitrone down-regulates interleukin-1β-stimulated matrix metalloproteinase-13 gene expression in human chondrocytes:: Suppression of c-jun NH2-terminal kinase, p38-mitogen-activated protein kinase and activating protein-1
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DOI：
10.1124/jpet.102.048611
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发表时间：
2003-06-01
影响因子：
3.5
通讯作者：
Haqqi, TM
中科院分区：
文献类型：
--
作者：
Ahmed, S;Rahman, A;Haqqi, TM
细胞因子介导的基质金属蛋白酶（MMPs）的诱导和过度表达被认为是关节炎发病机制中的重要因素。白细胞介素（IL）-1 β是一种促炎细胞因子，已知其在许多细胞类型中超诱导MMP-13的表达和产生。自旋捕获剂苯基N-叔丁基硝酮（PBN）可抑制IL-1 β诱导的人骨关节炎（OA）软骨细胞MMP-13的表达。MMP-13表达的下调与丝裂原活化蛋白激酶（MAPK）亚群c-Jun氨基末端激酶（JNK）和p38-MAPK活化的抑制、磷酸化c-jun的积累以及活化蛋白-1（AP-1）的DNA结合活性相关。体外激酶活性测定结果表明，外源性PBN完全阻断了JNK的c-Jun磷酸化活性。有趣的是，使用体外激酶测定，我们还发现软骨细胞p38-MAPK磷酸化c-Jun，PBN对抑制p38-MAPK的c-Jun磷酸化活性不是很有效。此外，PBN对p38-MAPK的ATF-2磷酸化活性和细胞外调节激酶p44/p42的Elk-1磷酸化活性无明显抑制作用，提示PBN可能选择性抑制OA软骨细胞c-Jun的磷酸化。总之，我们的研究结果首次表明，PBN抑制IL-1 β刺激的MMP-13在OA软骨细胞中的表达，这是通过抑制JNK和AP-1的激活来实现的。这些结果表明，使用PBN或衍生自PBN的化合物可能在抑制与关节炎中软骨降解相关的信号传导事件中具有潜在益处。
Cytokine-mediated induction and overexpression of matrix metalloproteinases (MMPs) is recognized as an important factor in the pathogenesis of arthritis. Interleukin (IL)-1beta is a proinflammatory cytokine that is known to superinduce the expression and production of MMP-13 in many cell types. Phenyl N-tert-butylnitrone (PBN), a spin trap agent, inhibited the IL-1beta-induced expression of MMP-13 in human osteoarthritis (OA) chondrocytes. Downregulation of MMP-13 expression correlated with the inhibition of mitogen-activated protein kinase (MAPK) subgroups c-Jun NH2-terminal kinase (JNK) and p38-MAPK activation, accumulation of phospho-c-jun, and the DNA binding activity of activating protein-1 (AP-1). Results of in vitro kinase assays showed that exogenously added PBN completely blocked the c-Jun phosphorylating activity of JNK. Interestingly, using in vitro kinase assay, we also found that chondrocyte p38-MAPK phosphorylate c-Jun and that PBN was not very effective in inhibiting c-Jun phosphorylating activity of p38-MAPK. In addition, PBN did not block the ATF-2 phosphorylating activity of p38-MAPK and Elk-1 phosphorylating activity of extracellular regulated kinase p44/p42 in vitro, indicating that PBN may act selectively to inhibit the phosphorylation of c-Jun in OA chondrocytes. Together, our results for the first time demonstrate that PBN suppresses the IL-1beta-stimulated expression of MMP-13 in OA chondrocytes and that this was achieved by inhibiting the activation of JNK and AP-1. These results suggest that use of PBN or compounds derived from it may be of potential benefit in inhibiting signaling events associated with cartilage degradation in arthritis.