RANTES stimulates Ca2+ mobilization and inositol trisphosphate (IP3) formation in cells transfected with G protein-coupled receptor 75
RANTES stimulates Ca2+ mobilization and inositol trisphosphate (IP3) formation in cells transfected with G protein-coupled receptor 75
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DOI：
10.1038/sj.bjp.0706909
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发表时间：
2006-11-01
影响因子：
7.3
通讯作者：
Schaller, H. C.
中科院分区：
文献类型：
--
作者：
Ignatov, A.;Robert, J.;Schaller, H. C.
背景和目的：RANTES是一种炎症趋化因子，在T淋巴细胞活化和增殖中发挥关键作用。其作用是通过 G 蛋白偶联七螺旋受体 (GPCR) 介导的。我们首次证明 RANTES 激活孤儿 G 蛋白偶联受体 75 (GPR75)。 实验方法：为了鉴定 GPR75 的配体，我们使用了三种不同且独立的方法，即荧光素酶测定、生物发光测定和 IP3 积累测定。 主要结果：用亚纳摩尔浓度的 RANTES 处理表达 GPR75 的细胞，导致刺激 报告基因检测中的荧光素酶活性、三磷酸肌醇和细胞内 Ca2(+) 的增加。后者的作用被磷脂酶 C 抑制剂 (PLC) U73122 阻断，表明 Gq 蛋白介导 GPR75 信号传导。 RANTES 增强 GPR75 转染细胞中 AKT 和丝裂原激活蛋白激酶 (MAPK) 的磷酸化，这种作用可被 PLC 抑制剂 U73122 和磷脂酰肌醇 3-激酶 (PI3K) 抑制剂渥曼青霉素阻断。海马细胞系 HT22 内源性表达 GPR75，但不表达其他已知的 RANTES 受体，用于研究 RANTES 和 GPR75 对神经元存活的影响。用 RANTES 处理 HT22 细胞，通过激活 PLC 和 PI3K，显着降低淀粉样蛋白-β 肽的神经毒性。 结论和意义：这清楚且毫无疑问地证明了 RANTES 作用于 GPR75 的能力。 RANTES/GPR75 信号通路的缺陷可能导致阿尔茨海默病中观察到的神经炎症和神经退行性过程。
Background and purpose: RANTES is an inflammatory chemokine with a critical role in T-lymphocyte activation and proliferation. Its effects are mediated through G protein-coupled heptahelical receptors (GPCRs). We show for the first time that RANTES activates the orphan G protein-coupled receptor 75 (GPR75).Experimental approach: To identify a ligand for GPR75 we have used three different and independent methods, namely luciferase assay, bioluminescence assay and IP3 accumulation assay.Key results: Treatment of cells expressing GPR75 with subnanomolar concentrations of RANTES led to stimulation of the luciferase activity in a reporter-gene assay, an increase in inositol trisphosphate, and intracellular Ca2(+). The latter effect was blocked by the phospholipase-C inhibitor ( PLC) U73122 indicating that Gq proteins mediate GPR75 signaling. RANTES enhanced the phosphorylation of AKT and mitogen-activated protein kinase ( MAPK) in GPR75-transfected cells and this effect was blocked by the PLC inhibitor U73122 and the phosphatidylinositol 3-kinase (PI3K) inhibitor, wortmannin. The hippocampal cell line HT22, which expresses GPR75 endogenously, but not the other known RANTES receptors, was used to study the effects of RANTES and GPR75 on neuronal survival. Treatment of HT22 cells with RANTES significantly reduced the neurotoxicity of amyloid-beta peptides, by activating PLC and PI3K.Conclusions and implications: This demonstrate clearly and undoubtedly the ability of RANTES to act on GPR75. Defects in the RANTES/GPR75-signaling pathway may contribute to neuroinflammatory and neurodegenerative processes as observed in Alzheimer's disease.