Release of Prostaglandin E2 and Nitric Oxide from Spinal Microglia Is Dependent on Activation of p38 Mitogen-Activated Protein Kinase
Release of Prostaglandin E2 and Nitric Oxide from Spinal Microglia Is Dependent on Activation of p38 Mitogen-Activated Protein Kinase
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DOI：
10.1213/ane.0b013e3181e3a2a2
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发表时间：
2010-08-01
影响因子：
5.7
通讯作者：
Yaksh, Tony L.
中科院分区：
文献类型：
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作者：
Matsui, Tomohiro;Svensson, Camilla I.;Yaksh, Tony L.
背景：脊髓中前列腺素（PGs）、一氧化氮（NO）和细胞因子的释放与脊髓伤害性感受过程有关。小胶质细胞代表了这些前兴奋介质的可能起源细胞。脊髓小胶质细胞具有Toll样受体4（TLR 4）和神经激肽1（NK 1）受体，这两种受体在外周神经损伤和炎症诱导的脊髓敏化中起重要作用。因此，我们检查了由各自靶点激活的级联的性质，这导致PGE（2）的释放和亚硝酸盐（NO2-）的增加。（一种NO的标记物）。分离自Sprague-Dawley新生大鼠的脊髓小胶质细胞，单独用脂多糖（LPS）或P物质（SP）培养，LPS与SP联合培养，并在环加氧酶（考克斯）、NO合酶2（NOS 2）或p38促分裂原活化蛋白激酶（p38）的每种抑制剂或米诺环素存在下与LPS一起作用24小时和48小时。分别用酶免疫分析法和比色法测定培养上清液中PGE（2）和NO2-的浓度。LPS的应用（TLR 4配体，0.1 - 10 ng/mL）对培养的小胶质细胞产生剂量和时间依赖性的PGE（2）和NO2-产生增加，而与SP孵育后没有观察到影响（NK 1激动剂，高达10（-5）M）单独或与LPS组合。SC-560（考克斯-1抑制剂）和SC-236（考克斯-2抑制剂）的拮抗剂研究表明，LPS诱导的PGE（2）释放由考克斯-1和考克斯-2产生。NOS 2抑制剂1400 W可抑制LPS诱导的NO释放。米诺环素（一种阻断小胶质细胞活化的药物）和SB 203580（一种p38抑制剂）都能减弱LPS诱导的PGE（2）和NO的释放。1400 W在抑制NO释放的剂量下，也阻断了PGE（2）释放的增加。结论：我们的研究结果表明：（a）通过TLR 4而不是NK 1受体激活脊髓小胶质细胞产生PGE（2）和NO释放;（B）诱发的PGE（2）释放由考克斯-1和考克斯-2产生，和（c）COX-PGE（2）途径由p38和NOS 2调节。结合我们之前的体内研究，目前的发现强调脊髓小胶质细胞中的p38是调节PGE（2）和NO等原伤害感受分子产生的关键参与者。
BACKGROUND: The spinal release of prostaglandins (PGs), nitric oxide (NO), and cytokines has been implicated in spinal nociceptive processing. Microglia represent a possible cell of origin for these proexcitatory mediators. Spinal microglia possess Toll-like receptor 4 (TLR4) and neurokinin 1 (NK1) receptors, and both receptors play a significant role in peripheral nerve injury- and inflammation-induced spinal sensitization. Accordingly, we examined the properties of the cascades activated by the respective targets, which led to the release of PGE(2) and an increase in nitrite (NO2-) (a marker of NO) from cultured rat spinal microglia.METHODS: Spinal microglia isolated from Sprague-Dawley neonatal rats were cultured with lipopolysaccharide (LPS) or substance P (SP) alone, with LPS in combination with SP, and with LPS in the presence of each inhibitor of cyclooxygenase (COX), NO synthase 2 (NOS2) or p38 mitogen-activated protein kinase (p38), or minocycline for 24 hours and 48 hours. Concentrations of PGE(2) and NO2- in culture supernatants were measured using an enzyme immunoassay and a colorimetric assay, respectively.RESULTS: Application of LPS (a TLR4 ligand, 0.1 to 10 ng/mL) to cultured microglia produced a dose- and time-dependent increase in PGE(2) and NO2- production, whereas no effects were observed after incubation with SP (an NK1 agonist, up to 10(-5) M) alone or in combination with LPS. Antagonist studies with SC-560 (COX-1 inhibitor) and SC-236 (COX-2 inhibitor) showed that LPS-induced PGE(2) release was generated from both COX-1 and COX-2. LPS-induced NO release was suppressed by 1400W, an inhibitor of NOS2. Minocycline, an agent blocking microglial activation, and SB203580, an inhibitor of p38, both attenuated the LPS-induced PGE(2) and NO release. The 1400W, at the doses that suppressed NO release, also blocked increased PGE(2) release.CONCLUSIONS: Our findings suggest that (a) activation of spinal microglia via TLR4 but not NK1 receptors produces PGE(2) and NO release from these cells; (b) the evoked PGE(2) release is generated by both COX-1 and COX-2, and (c) the COX-PGE(2) pathway is regulated by p38 and NOS2. Taken together with our previous in vivo work, the current findings emphasize that p38 in spinal microglia is a key player in regulating production of pronociceptive molecules, such as PGE(2) and NO. (Anesth Analg 2010;111:554-60)