Contribution of H3K4 Methylation by SET-1A to Interleukin-1-Induced Cyclooxygenase 2 and Inducible Nitric Oxide Synthase Expression in Human Osteoarthritis Chondrocytes
Contribution of H3K4 Methylation by SET-1A to Interleukin-1-Induced Cyclooxygenase 2 and Inducible Nitric Oxide Synthase Expression in Human Osteoarthritis Chondrocytes
复制标题
DOI：
10.1002/art.27762
复制
发表时间：
2011-01-01
影响因子：
--
通讯作者：
Fahmi, Hassan
中科院分区：
文献类型：
--
作者：
El Mansouri, Fatima Ezzahra;Chabane, Nadir;Fahmi, Hassan
Objective.研究组蛋白H3赖氨酸4（H3 K4）甲基化在白细胞介素1 β（IL-1 β）诱导的人骨关节炎（OA）软骨细胞环氧合酶2（考克斯-2）和诱导型一氧化氮合酶（iNOS）表达中的作用。用IL-1刺激软骨细胞，实时荧光定量RT-PCR和Western blotting分别检测诱导型一氧化氮合酶（iNOS）和考克斯-2（COX-2）mRNA和蛋白的表达。H3 K4甲基化以及组蛋白甲基转移酶SET-1A和MLL-1向iNOS和考克斯-2启动子的募集使用染色质免疫沉淀测定进行评估。使用甲基转移酶抑制剂5 '-脱氧-5'-（甲硫基）腺苷（MTA）和基因沉默实验进一步评估SET-1A的作用。采用免疫组化法测定软骨中SET-1A的含量。IL-1对iNOS和考克斯-2表达的诱导与iNOS和考克斯-2启动子上的H3 K4二甲基化和三甲基化有关。这些变化在时间上与组蛋白甲基转移酶SET-1A的募集相关，表明SET-1A在这些修饰中的作用。用MTA处理抑制IL-1诱导的H3 K4甲基化以及IL-1诱导的iNOS和考克斯-2表达。类似地，用小干扰RNA沉默SET-1A基因阻止了IL-1诱导的H3 K4在iNOS和考克斯-2启动子处的甲基化以及iNOS和考克斯-2表达。最后，我们发现SET-1A在OA软骨中的表达水平高于正常软骨。这些结果表明SET-1A引起的H3 K4甲基化有助于IL-1诱导的iNOS和考克斯-2表达，并提示该途径可能是治疗OA和其他关节炎疾病的药物干预的潜在靶点。
Objective. To investigate the role of histone H3 lysine 4 (H3K4) methylation in interleukin-1 beta (IL-1 beta)-induced cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) expression in human osteoarthritic (OA) chondrocytes.Methods. Chondrocytes were stimulated with IL-1, and the expression of iNOS and COX-2 messenger RNA and proteins was evaluated by real-time reverse transcriptase-polymerase chain reaction analysis and Western blotting, respectively. H3K4 methylation and the recruitment of the histone methyltransferases SET-1A and MLL-1 to the iNOS and COX-2 promoters were evaluated using chromatin immunoprecipitation assays. The role of SET-1A was further evaluated using the methyltransferase inhibitor 5'-deoxy-5'-(methylthio) adenosine (MTA) and gene silencing experiments. SET-1A level in cartilage was determined using immunohistochemistry.Results. The induction of iNOS and COX-2 expression by IL-1 was associated with H3K4 di- and trimethylation at the iNOS and COX-2 promoters. These changes were temporally correlated with the recruitment of the histone methyltransferase SET-1A, suggesting an implication of SET-1A in these modifications. Treatment with MTA inhibited IL-1-induced H3K4 methylation as well as IL-1-induced iNOS and COX-2 expression. Similarly, SET-1A gene silencing with small interfering RNA prevented IL-1-induced H3K4 methylation at the iNOS and COX-2 promoters as well as iNOS and COX-2 expression. Finally, we showed that the level of SET-1A expression was elevated in OA cartilage as compared with normal cartilage.Conclusion. These results indicate that H3K4 methylation by SET-1A contributes to IL-1-induced iNOS and COX-2 expression and suggest that this pathway could be a potential target for pharmacologic intervention in the treatment of OA and possibly other arthritic diseases.