Lin Kana, Fang Sanhua, Cai Beilei, Huang Xueqin, Zhang Xiayan, Lu Yunbi, Zhang Weiping, Wei Erqing
Department of Pharmacology and Institute of Neuroscience, School of Medicine, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, PR China; Department of Pharmacy, Second Affiliated Hospital (Binjiang Branch), School of Medicine, Zhejiang University, 1511 Jianghong Road, Hangzhou 310052, PR China.
Department of Pharmacology and Institute of Neuroscience, School of Medicine, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, PR China.
Eur J Cell Biol. 2014 Jul;93(7):278-88. doi: 10.1016/j.ejcb.2014.05.001. Epub 2014 May 20.
The CysLT2 receptor is involved in myocardial ischemia/reperfusion injury, differentiation of colorectal cancers, bleomycin-induced pulmonary inflammation and fibrosis. However, the signal transduction of cysteinyl leukotriene receptor 2 (CysLT2) in inflammatory responses remains to be clarified. In HEK293 cells stably expressing hCysLT1, hCysLT2 and rGPR17, we determined the signaling pathways for interleukin-8 (IL-8) production after CysLT2 receptor activation. HEK293 cells were stably transfected with the recombinant plasmids of pcDNA3.1(+)-hCysLT1, pcDNA3.1(+)-hCysLT2 and pcDNA3.1-rGPR17. Leukotriene C4 (LTC4) and LTD4 were used as the agonists to induce IL-8 production and the related changes in signal molecules. We found that LTC4 and LTD4 significantly induced IL-8 promoter activation in the HEK293 cells stably expressing hCysLT2, but not in those expressing hCysLT1 and rGPR17. In hCysLT2-HEK293 cells, LTC4 induced elevation of intracellular calcium, ERK1/2 phosphorylation and Egr-1 expression, and stimulated IL-8 expression and release. These responses were blocked by the selective CysLT2 receptor antagonist HAMI3379. The ERK1/2 inhibitor U0126 inhibited Egr-1 and IL-8 expression as well as IL-8 release, but the JNK and p38 inhibitors did not have the inhibitory effects. Down-regulation of Egr-1 by RNA interference with its siRNA inhibited the LTC4-induced IL-8 expression and release. In conclusion, these findings indicate the ERK-Egr-1 pathway of CysLT2 receptors mediates IL-8 production induced by the pro-inflammatory mediators LTC4 and LTD4.
半胱氨酰白三烯2（CysLT2）受体参与心肌缺血/再灌注损伤、结直肠癌的分化、博来霉素诱导的肺部炎症和纤维化。然而，半胱氨酰白三烯受体2（CysLT2）在炎症反应中的信号转导仍有待阐明。在稳定表达人CysLT1、人CysLT2和大鼠GPR17的HEK293细胞中，我们确定了CysLT2受体激活后白细胞介素-8（IL-8）产生的信号通路。用pcDNA3.1(+)-人CysLT1、pcDNA3.1(+)-人CysLT2和pcDNA3.1-大鼠GPR17的重组质粒稳定转染HEK293细胞。白三烯C4（LTC4）和白三烯D4（LTD4）用作激动剂来诱导IL-8产生以及信号分子的相关变化。我们发现，LTC4和LTD4在稳定表达人CysLT2的HEK293细胞中显著诱导IL-8启动子激活，但在表达人CysLT1和大鼠GPR17的细胞中则不然。在人CysLT2-HEK293细胞中，LTC4诱导细胞内钙升高、ERK1/2磷酸化和早期生长反应蛋白-1（Egr-1）表达，并刺激IL-8表达和释放。这些反应被选择性CysLT2受体拮抗剂HAMI3379阻断。ERK1/2抑制剂U0126抑制Egr-1和IL-8表达以及IL-8释放，但JNK和p38抑制剂没有抑制作用。用其小干扰RNA（siRNA）通过RNA干扰下调Egr-1可抑制LTC4诱导的IL-8表达和释放。总之，这些发现表明CysLT2受体的ERK-Egr-1途径介导促炎介质LTC4和LTD4诱导的IL-8产生。
