Role of HuR and p38MAPK in Ultraviolet B-induced Post-transcriptional Regulation of COX-2 Expression in the Human Keratinocyte Cell Line HaCaT
Role of HuR and p38MAPK in Ultraviolet B-induced Post-transcriptional Regulation of COX-2 Expression in the Human Keratinocyte Cell Line HaCaT
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DOI：
10.1074/jbc.m109.081430
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发表时间：
2010-02-05
影响因子：
4.8
通讯作者：
Klotz, Lars-Oliver
中科院分区：
文献类型：
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作者：
Fernau, Niklas S.;Fugmann, Dominik;Klotz, Lars-Oliver
COX-2（环氧化酶-2）在炎症过程中起关键作用，紫外线辐射是皮肤细胞中COX-2表达的已知刺激。在这里，逆转录pcr和Western blotting证实，HaCaT人角质形成细胞中COX-2表达的诱导仅在UVB （280-320 nm）照射下观察到，而在UVA辐射（320-400 nm）下没有观察到。UVB照射下HaCaT细胞培养上清液中前列腺素E-2水平升高。紫外线辐射显著提高了COX-2 mRNA的稳定性。抑制和小干扰rna诱导的p38（MAPK）缺失均可阻止UVB诱导COX-2 mRNA的稳定和COX-2稳态mRNA和蛋白水平的增强，p38（MAPK）是一种暴露于UVB后强烈激活的激酶，这表明p38mapk依赖性mRNA的稳定是UVB诱导COX-2表达的一种机制。UVB诱导的COX-2表达的急剧下降是由p38MAPK调节的应激响应mRNA稳定蛋白（即HuR）的小干扰rna缺失引起的；uvb诱导的COX-2 mRNA和蛋白水平升高与细胞质中HuR的积累相一致，并且在HuR耗尽的细胞中减弱。此外，UVB诱导的HaCaT细胞生成前列腺素E-2被HuR耗尽削弱，这表明应激激酶（如p38MAPK）和HuR是旨在干扰UVB诱导COX-2表达的方法的极好靶点。
COX-2 (cyclooxygenase-2) is a pivotal player in inflammatory processes, and ultraviolet radiation is a known stimulus for COX-2 expression in skin cells. Here, an induction of COX-2 expression in HaCaT human keratinocytes was observed only upon exposure of cells to UVB (280-320 nm) but not to UVA radiation (320-400 nm), as demonstrated by reverse transcription-PCR and Western blotting. Prostaglandin E-2 levels were elevated in cell culture supernatants of HaCaT cells exposed to UVB. COX-2 mRNA stability was dramatically increased by UV Birradiation. Both the stabilization of COX-2 mRNA and the enhancement of COX-2 steady-state mRNA and protein levels caused by UVB were prevented both by inhibition and small interfering RNA-induced depletion of p38(MAPK), a kinase strongly activated upon exposure to UVB, suggesting p38MAPK-dependent mRNA stabilization as a mechanism of UVB-induced COX-2 expression. A dramatic decrease in COX-2 expression induced by UVB was elicited by small interfering RNA-based depletion of a stress-responsive mRNA stabilizing protein regulated by p38MAPK, i.e. HuR; UVB-induced elevation of COX-2 mRNA and protein levels coincided with an accumulation of HuR in the cytoplasm and was attenuated in cells depleted of HuR. Moreover, UVB-induced generation of prostaglandin E-2 by HaCaT cells was blunted by HuR depletion, suggesting that stress kinases (such as p38MAPK) as well as HuR are excellent targets for approaches aiming at interfering with induction of COX-2 expression by UVB.