Dexamethasone inhibits IL-1β gene expression in LPS-stimulated RAW 264.7 cells by blocking NF-κB/Rel and AP-1 activation
Dexamethasone inhibits IL-1β gene expression in LPS-stimulated RAW 264.7 cells by blocking NF-κB/Rel and AP-1 activation
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DOI：
10.1016/s0162-3109(00)00199-5
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发表时间：
2000-07-20
期刊：
影响因子：
--
通讯作者：
Kim, HM
中科院分区：
文献类型：
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作者：
Jeon, YJ;Han, SH;Kim, HM
在本研究中，地塞米松（DEX）抑制细菌脂多糖（LPS）激活的RAW 264.7细胞中IL-1 β基因表达的机制进行了研究。定量逆转录聚合酶链反应（RT-PCR）证实LPS诱导的IL-1 β mRNA表达减少。由于IL-1 β基因的启动子含有NF-κ B/Rel、AP-1、NF-IL 6和CREB/ATF的结合基序，这些基序在LPS介导的IL-1 β诱导中似乎是重要的，因此检测了DEX对这些转录因子活化的影响。DEX处理RAW 264.7细胞诱导NF-κ B B/Rel和AP-1在氯霉素乙酰转移酶活性中的剂量相关性抑制，而NF-IL 6和CREB B/ATF活化均不受DEX影响。用DEX处理RAW 264.7细胞抑制NF-κ B/Rel和AP-1蛋白与其同源DNA位点的DNA结合，如通过电泳迁移率变动测定（EMSA）所测量的。DEX处理引起细胞核c-rel，p65和p50蛋白含量的显着减少，这些减少是由细胞质c-rel，p65和p50的积累。DEX处理RAW 264.7细胞不抑制c-jun和c-fos的核转位。我们发现DEX对IL-1 β产生的抑制与p38无关，p38在IL-1 β诱导中很重要。这些结果表明，DEX可能通过阻断LPS诱导的NF-κ B/Rel和AP-1活化来抑制IL-1 β基因表达。(C)2000 Elsevier Science B. V.保留所有权利。
In the present study, the mechanism by which dexamethasone (DEX) inhibited IL-1 beta gene expression in bacterial lipopolysaccharide (LPS)-activated RAW 264.7 cells was investigated. The decrease in LPS-induced IL-1 beta mRNA expression was demonstrated by quantitative reverse transcription polymerase chain reaction (RT-PCR). Since the promoter in IL-1 beta gene contains binding motifs for NF-kappa B/Rel, AP-1, NF-IL6, and CREB/ATF, which appear to be important in LPS-mediated IL-1 beta induction, the effects of DEX on the activation of these transcription factors were examined. Treatment of DEX to RAW 264.7 cells induced a dose-related inhibition of NF-kappa B/Rel and AP-1 in chloramphenicol acetyltransferase activity, while neither NF-IL6 nor CREB/ATF activation was affected by DEX. Treatment of RAW 264.7 cells with DEX inhibited DNA binding of NF-kappa B/Rel and AP-1 proteins to their cognate DNA sites as measured by electrophoretic mobility shift assay (EMSA). DEX treatment caused a significant reduction in nuclear c-rel, p65, and p50 protein contents, and these decreases were paralleled by the accumulation of cytoplasmic c-rel, p65, and p50. DEX treatment of RAW 264.7 cells did not inhibit the nuclear translocation of c-jun and c-fos. We found that the inhibition of IL-1 beta production by DEX is not related to p38, which is important in the IL-1 beta induction. These results suggest that DEX may inhibit IL-1 beta gene expression by a mechanism involving the blocking of LPS-induced NF-kappa B/Rel and AP-1 activation. (C) 2000 Elsevier Science B.V. All rights reserved.