Prostaglandin E2-induced intercellular adhesion molecule-1 expression is mediated by cAMP/Epac signalling modules in bEnd.3 brain endothelial cells
Prostaglandin E2-induced intercellular adhesion molecule-1 expression is mediated by cAMP/Epac signalling modules in bEnd.3 brain endothelial cells
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DOI：
10.1111/bph.12103
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发表时间：
2013-06-01
影响因子：
7.3
通讯作者：
Lee, Soo Hwan
中科院分区：
文献类型：
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作者：
Park, Tae Yeop;Baik, Eun Joo;Lee, Soo Hwan
背景和目的 前列腺素 E2 (PGE2) 与粘附分子、白细胞粘附和炎症部位浸润的调节有关。然而，其中涉及的根本机制仍然不明确。在本研究中，我们探讨了其调节脑内皮细胞细胞间粘附分子-1（ICAM-1）表达的细胞作用机制。实验方法用PGE 2 处理bEnd.3细胞、鼠脑血管内皮细胞系和原代小鼠脑内皮细胞，有或没有PGE 2 受体激动剂/拮抗剂和相关信号分子。通过逆转录聚合酶链反应（RT-PCR）、免疫印迹分析、荧光素酶测定和免疫细胞化学测定ICAM-1表达、Akt磷酸化和NF-B活性。主要结果 PGE2 显着上调 ICAM-1 的表达，而 ICAM-1 的表达可被 EP4 拮抗剂 (ONO-AE2-227) 和 EP4 敲低所阻断。 PGE2 效应由毛喉素、二丁酰 cAMP (dbcAMP) 和由 cAMP (Epac) 激活剂 (8-Cpt-cAMP) 直接激活的交换蛋白模拟，但不是蛋白激酶 A 激活剂 (N6-Bnz-cAMP)。通过敲除 Epac1，PGE2 诱导的 ICAM-1 表达减少。 PI3K 特异性抑制剂 (LY294002)、Akt 抑制剂 VIII (Akti) 和 NF-B 抑制剂（Bay-117082 和 MG-132）可减弱 PGE2 对 ICAM-1 的诱导。 PGE2、dbcAMP 和 8-Cpt-cAMP 诱导 Akt、IB 激酶和 IB 磷酸化以及 p65 易位至细胞核，并增加 NF-B 依赖性报告基因活性，而 Akti 可减弱这种活性。结论和意义我们的研究结果表明，PGE2 通过 bEnd.3 脑内皮细胞中的 EP4 受体和 Epac/Akt/NF-B 信号通路诱导 ICAM-1 表达，支持其在脑炎症中的病理生理学作用。
Background and Purpose Prostaglandin E2 (PGE2) has been implicated in the regulation of adhesion molecules, leukocyte adhesion and infiltration into inflamed site. However, the underlying mechanism therein involved remains ill-defined. In this study, we explored its cellular mechanism of action in the regulation of the intercellular adhesion molecule-1 (ICAM-1) expression in the brain endothelial cells. Experimental Approach bEnd.3 cells, the murine cerebrovascular endothelial cell line and primary mouse brain endothelial cells were treated with PGE2 with or without agonists/antagonists of PGE2 receptors and associated signalling molecules. ICAM-1 expression, Akt phosphorylation and activity of NF-B were determined by reverse transcription polymerase chain reaction (RT-PCR), immunoblot analysis, luciferase assay and immunocytochemistry. Key Results PGE2 significantly up-regulated the expression of ICAM-1, which was blocked by EP4 antagonist (ONO-AE2-227) and knock-down of EP4. PGE2 effects were mimicked by forskolin, dibutyryl cAMP (dbcAMP) and an exchange protein directly activated by cAMP (Epac) activator (8-Cpt-cAMP) but not a protein kinase A activator (N6-Bnz-cAMP). PGE2-induced ICAM-1 expression was reduced by knock-down of Epac1. A PI3K specific inhibitor (LY294002), Akt inhibitor VIII (Akti) and NF-B inhibitors (Bay-117082 and MG-132) attenuated the induction of ICAM-1 by PGE2. PGE2, dbcAMP and 8-Cpt-cAMP induced the phosphorylation of Akt, IB kinase and IB and the translocation of p65 to the nucleus and increased NF-B dependent reporter gene activity, which was diminished by Akti. Conclusion and Implications Our findings suggest that PGE2 induces ICAM-1 expression via EP4 receptor and Epac/Akt/NF-B signalling pathway in bEnd.3 brain endothelial cells, supporting its pathophysiological role in brain inflammation.