Cheng Xiu-Li, Ding Fan, Li Hui, Tan Xiao-Qiu, Liu Xiao, Cao Ji-Min, Gao Xue
Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing, China.
Office of Scientific R&D, Tsinghua University, Beijing, China.
Biochem Biophys Res Commun. 2015 May 29;461(2):275-80. doi: 10.1016/j.bbrc.2015.04.015. Epub 2015 Apr 11.
The relationship between glutamate signaling and inflammation has not been well defined. This study aimed to investigate the role of AMPA receptor (AMPAR) in the expression and release of tumor necrosis factor-alpha (TNF-α) from macrophages and the underlying mechanisms. A series of approaches, including confocal microscopy, immunofluorescency, flow cytometry, ELISA and Western blotting, were used to estimate the expression of AMPAR and downstream signaling molecules, TNF-α release and reactive oxygen species (ROS) generation in the macrophage-like RAW264.7 cells. The results demonstrated that AMPAR was expressed in RAW264.7 cells. AMPA significantly enhanced TNF-α release from RAW264.7 cells, and this effect was abolished by CNQX (AMPAR antagonist). AMPA also induced elevation of ROS production, phosphorylation of c-Src and activation of nuclear factor (NF)-κB in RAW264.7 cells. Blocking c-Src by PP2, scavenging ROS by glutathione (GSH) or inhibiting NF-κB activation by pyrrolidine dithiocarbamate (PDTC) decreased TNF-α production from RAW264.7 cells. We concluded that AMPA promotes TNF-α release in RAW264.7 macrophages likely through the following signaling cascade: AMPAR activation → ROS generation → c-Src phosphorylation → NF-κB activation → TNF-α elevation. The study suggests that AMPAR may participate in macrophage activation and inflammation.
谷氨酸信号传导与炎症之间的关系尚未明确界定。本研究旨在探讨α-氨基-3-羟基-5-甲基-4-异恶唑丙酸受体(AMPAR)在巨噬细胞肿瘤坏死因子-α(TNF-α)表达和释放中的作用及其潜在机制。采用了一系列方法,包括共聚焦显微镜、免疫荧光、流式细胞术、酶联免疫吸附测定(ELISA)和蛋白质印迹法,来评估巨噬细胞样RAW264.7细胞中AMPAR及下游信号分子的表达、TNF-α释放和活性氧(ROS)生成。结果表明,RAW264.7细胞中表达了AMPAR。AMPA显著增强了RAW264.7细胞中TNF-α的释放,而CNQX(AMPAR拮抗剂)可消除这种作用。AMPA还诱导RAW264.7细胞中ROS生成增加、c-Src磷酸化以及核因子(NF)-κB激活。用PP2阻断c-Src、用谷胱甘肽(GSH)清除ROS或用吡咯烷二硫代氨基甲酸盐(PDTC)抑制NF-κB激活,均可降低RAW264.7细胞中TNF-α的产生。我们得出结论,AMPA可能通过以下信号级联反应促进RAW264.7巨噬细胞中TNF-α的释放:AMPAR激活→ROS生成→c-Src磷酸化→NF-κB激活→TNF-α升高。该研究表明,AMPAR可能参与巨噬细胞激活和炎症反应。