Inhibition of mitogen-activated protein kinase signaling by chloroquine
Inhibition of mitogen-activated protein kinase signaling by chloroquine
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DOI：
10.4049/jimmunol.168.10.5303
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发表时间：
2002-05-15
影响因子：
4.4
通讯作者：
Levitz, SM
中科院分区：
文献类型：
--
作者：
Weber, SM;Chen, JM;Levitz, SM
在此之前，我们证明了抗炎药氯喹(CQ)能抑制内毒素诱导的肿瘤坏死因子-α转录。为了进一步明确CQ的作用机制，我们研究了该药对参与调节肿瘤坏死因子产生的丝裂原活化蛋白激酶信号通路的影响。CQ干扰细胞外信号调节蛋白(ERK)1/2和ERK激活蛋白/ERK激酶(MEK)1/2的磷酸化。CQ和MEK1抑制剂PD98059均降低由人肿瘤坏死因子启动子序列驱动的荧光素酶报告活性。然而，CQ似乎通过去激活MEK的上游激活物Raf来调节这些效应。这些发现得到了功能数据的支持，这些数据表明，CQ和PD98059干扰了几种人和小鼠细胞类型的肿瘤坏死因子的表达，而这两种抑制剂都没有阻止小鼠RAW264.7巨噬细胞产生肿瘤坏死因子，而RAW264.7巨噬细胞系不需要MEK-ERK信号来产生肿瘤坏死因子。最后，我们评估了CQ是否可以敏化HeLa细胞经历抗Fas介导的凋亡，当ERK激活在该细胞系中被中断时观察到的效果。CQ以类似于PD98059的方式使HeLa细胞对抗Fas处理敏感。综上所述，这些数据表明，治疗浓度的CQ通过一种新的机制干扰ERK的激活，这种效应可能至少部分地导致了这种药物的强大抗炎作用。
Previously, we demonstrated that the anti-inflammatory drug chloroquine (CQ) inhibited LPS-induced TNF-alpha transcription. To define further the mechanism of CQ, we studied the effect of this drug on mitogen-activated protein kinase signaling pathways involved in regulation of TNF production. CQ interfered with phosphorylation of extracellular signal-regulated kinases (ERK)1/2 and the ERK-activating kinases mitogen-activating protein/ERK kinase (MEK)1/2. Both CQ and PD98059, a MEK1 inhibitor, reduced luciferase reporter activity driven by human TNF promoter sequences. However, CQ appeared to mediate these effects by deactivating Raf, the upstream activator of MEK. These findings were supported by functional data demonstrating that CQ and PD98059 interfered with TNF expression in several human and murine cell types while neither inhibitor blocked TNF production in murine RAW264.7 macrophages, a cell line that does not require MEK-ERK signaling for TNF production. Finally, we evaluated whether CQ could sensitize HeLa cells to undergo anti-Fas-mediated apoptosis, an effect observed when ERK activation is interrupted in this cell line. CQ rendered HeLa cells sensitive to anti-Fas treatment in a manner similar to PD98059. Taken together, these data argue that therapeutic concentrations of CQ interfere with ERK activation by a novel mechanism, an effect that could be responsible, at least in part, for the potent anti-inflammatory effects of this drug.