G-Protein-Coupled Receptor Screen Reveals a Role for Chemokine Receptor CCR5 in Suppressing Microglial Neurotoxicity
G-Protein-Coupled Receptor Screen Reveals a Role for Chemokine Receptor CCR5 in Suppressing Microglial Neurotoxicity
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DOI：
10.1523/jneurosci.2920-08.2008
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发表时间：
2008-11-12
影响因子：
5.3
通讯作者：
Kiyama, Hiroshi
中科院分区：
文献类型：
--
作者：
Gamo, Kazushige;Kiryu-Seo, Sumiko;Kiyama, Hiroshi
G蛋白偶联受体（GPCR）形成膜蛋白的最大超家族，并且几个GPCR已经涉及神经元和胶质细胞之间的信号传导以保护神经元免受病理应激。在这里，我们使用了一种筛选策略来研究参与神经元保护的GPCR。使用数据库中列出的274种靶向非感官GPCR mRNA的引物进行实时PCR。用正常和神经损伤的小鼠脑舌下神经核的cDNA，比较PCR产物的变化。该筛选和随后的原位杂交筛选显示了6个GPCR mRNA，这些mRNA在神经损伤的舌下神经核中被显著且令人信服地诱导。在这些候选者中，基于神经损伤后小胶质细胞中CCR 5 mRNA的显著诱导，选择趋化因子受体CCR 5。在损伤的运动神经元中诱导了CCR 5配体的mRNA表达，例如活化正常T细胞表达和分泌的受调节的（RANTES/CCL 5）、MIP-1 α和MIP-1 β，表明CCR 5及其配体分别在小胶质细胞和神经元中表达，以响应神经损伤。在体外，脂多糖（LPS）诱导的炎症细胞因子（IL-1 β，IL-6和肿瘤坏死因子-α）和诱导型一氧化氮合酶（iNOS）的mRNA表达在小胶质细胞中均被RANTES抑制。在CCR 5基因敲除小鼠的小胶质细胞中未观察到这些细胞悬液。此外，在野生型C56 BL/6 J小鼠中观察到的神经损伤诱导的运动神经元死亡在CCR 5敲除的C57 BL/6 J中加速。这些结果可能表明，CCR 5介导的神经胶质细胞信号功能，以保护神经元抑制小胶质细胞毒性。
G-protein-coupled receptors (GPCRs) form the largest superfamily of membrane proteins, and several GPCRs have been implicated in signaling between neurons and glia to protect neurons from pathological stresses. Here, we have used a screening strategy to investigate GPCRs that are involved in neuronal protection. The real-time PCR was performed using 274 primers targeting nonsensory GPCR mRNAs, which were listed on the database. The cDNAs from control and nerve-injured hypoglossal nuclei of mouse brain were used, and the alterations of PCR products were compared. This screen and the subsequent in situ hybridization screen exhibited six GPCR mRNAs which were prominently and convincingly induced in nerve-injured hypoglossal nuclei. Among these candidates, the chemokine receptor CCR5 was selected, based on the marked induction in CCR5 mRNA in microglia after nerve injury. The mRNA expression of ligands for CCR5, such as regulated on activation normal T-cell expressed and secreted (RANTES/CCL5), MIP-1 alpha, and MIP-1 beta, were induced in injured motor neurons, indicating that CCR5 and its ligands were expressed in microglia and neurons, respectively, in response to nerve injury. In vitro, lipopolysaccharide (LPS)-induced expression of mRNAs for inflammatory cytokines (IL-1 beta, IL-6, and tumor necrosis factor-alpha) and inducible nitric oxide synthase (iNOS) in microglia were all suppressed by RANTES. Those suppressions were not observed in microglia from CCR5 null mice. In addition, nerve injury-induced motor neuron death seen in wild type C56BL/6J mice was accelerated in CCR5 knock-out C57BL/6J. These results may suggest that CCR5-mediated neuron-glia signaling functions to protect neurons by suppressing microglia toxicity.