LPS-induced iNOS expression in Bv-2 cells is suppressed by an oxidative mechanism acting on the JNK pathway-A potential role for neuroprotection
LPS-induced iNOS expression in Bv-2 cells is suppressed by an oxidative mechanism acting on the JNK pathway-A potential role for neuroprotection
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DOI：
10.1016/j.brainres.2010.01.082
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发表时间：
2010-03-31
期刊：
影响因子：
2.9
通讯作者：
Land, Tiit
中科院分区：
文献类型：
--
作者：
Svensson, Christina;Fernaeus, Sandra Zetterstrom;Land, Tiit
在慢性炎症期间观察到的活化的小胶质细胞产生并分泌高浓度或持续产生期间可能导致神经元细胞死亡的化合物。诱导型一氧化氮合酶（iNOS）响应于各种免疫刺激而表达，并催化自由基一氧化氮（NO）的形成，其在低水平和受调节的水平下参与细胞信号传导和细胞保护事件，而其较高水平和不受调节的产生可促进细胞或组织中的神经毒性。因此，NO产生的调节对于将NO水平维持在安全窗口内至关重要。我们分析了诱导型一氧化氮合酶蛋白的表达和NO的产生，在小鼠小胶质细胞Bv-2细胞16小时后处理的细菌内毒素脂多糖（LPS）。我们进一步分析了三种MAPK途径，通过用LPS和ERK 1/2、p38或JNK MAPK活性的抑制剂共处理细胞。为了研究氧化调节机制的参与，还用抗氧化剂N-乙酰基-L-半胱氨酸（NAC）处理细胞。我们的研究结果表明，LPS诱导的Bv-2细胞的iNOS表达主要是通过JNK MAPK介导的。此外，用LPS和NAC共处理Bv-2细胞令人惊讶地进一步增加了iNOS表达，也发现该作用通过JNK MAPK途径介导。磷酸化JNK MAPK（p46）的水平被单独的LPS强烈增加，并且当与NAC组合时进一步增加。我们的数据表明，iNOS和NO的生产受到抑制的氧化机制作用于JNK MAPK途径，我们推测，它可能构成一个潜在的调节机制控制NO水平。(C)2010爱思唯尔有限公司版权所有。
Activated microglia cells, observed during chronic inflammation, produce and secrete compounds that at high concentrations or during sustained production might cause neuronal cell death. Inducible nitric oxide synthase (iNOS) is expressed in response to various immunological stimuli and catalyses the formation of the free radical nitric oxide (NO), that at low and regulated levels participate in cell signaling and cytoprotective events, whereas its higher and unregulated production can promote neurotoxicity in cells or in tissues. Regulation of NO production is therefore central for maintaining NO-levels within a safe window. We have analyzed iNOS protein expression and NO production, in murine microglial Bv-2 cells after 16 h treatment with the bacterial endotoxin lipopolysaccharide (LPS). We have further analyzed three MAPK pathways, by co-treating the cells with LPS and the inhibitors of ERK1/2, p38 or JNK MAPK activities. To investigate participation of an oxidative regulatory mechanism, cells were also treated with the antioxidant N-acetyl-L-cysteine (NAC). Our results show that LPS-induced iNOS expression in Bv-2 cells is mainly mediated through JNK MAPK. In addition, co-treatment of the Bv-2 cells with LPS and NAC surprisingly further increased the iNOS expression, an effect also found to be mediated through the JNK MAPK pathway. The level of phosphorylated JNK MAPK (p46) was strongly increased by LPS alone and was further increased when combined with NAC. Our data indicate that iNOS and NO production are suppressed by an oxidative mechanism acting on the JNK MAPK pathway and we speculate that it might constitute a potential regulatory mechanism controlling the NO level. (C) 2010 Elsevier B.V. All rights reserved.