Kinase-dependent, retinoic acid receptor-independent up-regulation of cyclooxygenase-2 by all-trans retinoic acid in human mesangial cells
Kinase-dependent, retinoic acid receptor-independent up-regulation of cyclooxygenase-2 by all-trans retinoic acid in human mesangial cells
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DOI：
10.1038/sj.bjp.0706842
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发表时间：
2006-09-01
影响因子：
7.3
通讯作者：
Lucio-Cazana, F. J.
中科院分区：
文献类型：
--
作者：
Alique, M.;Moreno, V.;Lucio-Cazana, F. J.
背景和目的：在人肾小球系膜细胞（MC）中的初步结果表明，全反式维甲酸（ATRA）增加MC中考克斯-2的表达和具有抗炎作用的PG-前列腺素E-2（PGE（2））的产生。本研究的目的是证实ATRA可增加MC中考克斯-2的表达，并探讨其作用机制。Western blot检测考克斯表达和激酶活性。通过北方杂交、RT-PCR和启动子分析等方法分析了ATRA诱导的考克斯-2、考克斯-1表达和PGE（2）生成的转录机制。考克斯-2在PGE（2）的产生中起作用，因为考克斯-1抑制剂SC-560仅部分抑制PGE（2）的产生。ATRA上调考克斯-2是由于转录机制，因为与放线菌素D预孵育消除了它，ATRA增加了考克斯-2 mRNA的表达和人考克斯-2启动子构建体的活性，ATRA上调考克斯-2的过程中不涉及视黄酸受体（RAR），因为RAR-泛受体拮抗剂和RAR-泛受体拮抗剂均不抑制RAR-泛受体的上调，激动剂TTNPB不上调考克斯-2。相反，ATRA可能通过持续激活细胞外信号调节激酶1/2（ERK 1/2）发挥作用，因为PD 098059抑制ERK 1/2的激活可阻止考克斯-2的上调。此外，ERK 1/2，以及下游信号转导蛋白ERK 1/2，仍然磷酸化时，考克斯-2增加24 h后。结论和影响：这些结果突出了RAR的独立机制的生物效应的ATRA的相关性。
Background and purpose: Preliminary results in human mesangial cells (MC) suggested that all-trans retinoic acid (ATRA) increased the expression of COX-2 and the production of prostaglandin E-2 (PGE(2)), a PG with anti-inflammatory effects in MC. The aim of this work is to confirm that ATRA increases the expression of COX-2 in MC and to examine the mechanisms involved.Experimental approach: Cultured MC were treated with ATRA. COX expression and kinase activity were analyzed by Western blot. Transcriptional mechanisms were analyzed by Northern blot, RT-PCR and promoter assays.Key results: COX-2 and COX-1 expression and PGE(2) production were increased by ATRA. COX-2 played a role in PGE(2) production as production was only partially inhibited by COX-1 inhibitor SC-560. COX-2 up-regulation by ATRA was due to transcriptional mechanisms as pre-incubation with actinomycin D abolished it and ATRA increased the expression of COX-2 mRNA and the activity of a human COX-2 promoter construct, whereas post-transcriptional mechanisms were not found. Retinoic acid receptors (RAR) were not involved in the up-regulation of COX-2 by ATRA since it was not inhibited by RAR-pan-antagonists and the RAR-pan-agonist TTNPB did not up-regulate COX-2. Instead ATRA might act through a sustained activation of extracellular signal-regulated kinase 1/2 (ERK1/2) since up-regulation of COX-2 was prevented by inhibition of the activation of ERK1/2 with PD098059. Also ERK1/2, as well as downstream signalling proteins from ERK1/2, remained phosphorylated when COX-2 increased 24 h later.Conclusions and implications: These results highlight the relevance of RAR-independent mechanisms to the biological effects of ATRA.