Discovery of novel functions of brain microglia and their in vivo analysis.

脑小胶质细胞新功能的发现及其体内分析。

• 批准号: 11670089
• 负责人: NAKATA Yoshihiro
• 金额: $ 1.92万
• 依托单位: Hiroshima University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11670089/
• 关键词: Microglia; ATP; TNF-α; P2X_7 receptor; Ca^<2+>; ERK; p38; P2X_7; ホスホリパーゼD

Upon pathological changes such as brain ischemia or inflammation, microglia are rapidly activated and secrete various cytokines, including TNF-α, which plays not only harmful, but also protective roles for neurons. Despite importance of microglia-derived TNF-α, it remains unknown how the release of TNF-α is regulated. Recently it was revealed that ATP, which is released from nerve terminals, activated immune cells or damaged cells, activates microglia via cell surface P2 receptors, at least G-protein-coupled P2Y_2 and ionotropic P2X_7. In this study, we found that ATP stimulates the release of TNF-α, resulting from mRNA expression in rat cultured brain microglia. The release of TNF-α was maximally elicited by 1 mM ATP and also induced by a P2X_7 selective agonist, 2'-and 3'-O-(4-benzoylbenzoyl)-adenosine 5'-triphosphate (BzATP), and BzATP-induced TNF-α was inhibited by Brilliant Blue G, a selective antagonist of rat P2X_7 receptor. ATP-or BzATP-induced TNF-α release was inhibited by PD98059 and U-0126, inhibitors of MEK1, which activates ERK, and also by SB203580, an inhibitor of p38 MAP kinase, while BzATP-stimulated mRNA expression of TNF-α was inhibited by U-0126, but not by SB203580. These results indicate that extracellular ATP triggers TNF-α release in rat microglia at least via P2X_7 receptor and suggest that signaling to the release of TNF-α involves ERK and p38 MAP kinase, which play distinct roles at the transcriptional and the post-transcriptional levels, respectively.

在脑缺血或炎症等病理变化时，小胶质细胞迅速活化并分泌包括TNF-α在内的多种细胞因子，对神经元既有损伤作用，又有保护作用。尽管小胶质细胞源性TNF-α的重要性，但TNF-α的释放是如何调节的仍不清楚。近年来研究发现，ATP通过细胞表面P2受体，至少是G蛋白偶联的P2Y_2和亲离子的P2X_7，激活小胶质细胞，ATP可从神经末梢、激活的免疫细胞或损伤的细胞中释放。在本研究中，我们发现ATP刺激培养的大鼠脑小胶质细胞释放TNF-α，导致mRNA的表达。1 mM ATP能最大程度地诱导TNF-α的释放，P2X_7受体选择性激动剂2 ′-和3 ′-O-（4-苯甲酰基苯甲酰基）-腺苷5 ′-三磷酸（BzATP）也能诱导TNF-α的释放，大鼠P2X_7受体选择性拮抗剂Brilliant Blue G可抑制BzATP诱导的TNF-α释放。ATP或BzATP诱导的TNF-α释放被激活ERK的MEK 1抑制剂PD 98059和U-0126以及p38 MAP激酶抑制剂SB 203580抑制，而BzATP刺激的TNF-α mRNA表达被U-0126抑制，但不被SB 203580抑制。这些结果表明，细胞外ATP至少通过P2 X7受体触发大鼠小胶质细胞TNF-α的释放，并提示ERK和p38 MAP激酶参与了TNF-α释放的信号转导，它们分别在转录和转录后水平发挥不同的作用。

项目成果

Izumi Hide, Tomohisa Suzuki, Atsuko Inoue, and Yoshihiro Nakata: "Regulation of TNF-α release from microglia by ATP."Neurochemical Research. (in press).

Izumi Hide、Tomohisa Suzuki、Atsuko Inoue 和 Yoshihiro Nakata：“ATP 对小胶质细胞释放 TNF-α 的调节”。神经化学研究（正在出版）。

Izumi Hide, Masaya Tanaka, Atsuko Inoue, Kazuyuki Nakajima, Shinichi Kohsaka, Kazuhide Inoue, and Yoshihiro Nakata: "Extracellular ATP triggers tumor necrosis factor-α release from rat microglia."Journal of Neurochemistry. 75. 965-972 (2000)

Izumi Hide、Masaya Tanaka、Atsuko Inoue、Kazuyuki Nakajima、Shinichi Kohsaka、Kazuhide Inoue 和 Yoshihiro Nakata：“细胞外 ATP 触发大鼠小胶质细胞释放肿瘤坏死因子-α。”神经化学杂志 75. 965-972 (2000)。

I.Hide,M.Tanaka,A.Inoue,K.Nakajima,S.Kohsaka,K.Inoue & Y.Nakata: "Extracellular ATP triggers tumor necrosis factor-α release from rat microglia."Journal of Neurochemistry. 75. 965-972 (2000)

I.Hide、M.Tanaka、A.Inoue、K.Nakajima、S.Kohsaka、K.Inoue 和 Y.Nakata：“细胞外 ATP 触发大鼠小胶质细胞释放肿瘤坏死因子-α”。《神经化学杂志》75. 965。 -972 (2000)

I.Hide,T.Suzuki,A.Inoue,and Y.Nakata: "Regulation of TNF-α release from microglia by ATP"Neurochemical Research. (in press). (2001)

I.Hide、T.Suzuki、A.Inoue 和 Y.Nakata：“ATP 对小胶质细胞释放 TNF-α 的调节”神经化学研究（2001 年出版）。