NCX1 Expression and Functional Activity Increase in Microglia Invading the Infarct Core
NCX1 Expression and Functional Activity Increase in Microglia Invading the Infarct Core
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DOI：
10.1161/strokeaha.109.557439
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发表时间：
2009-11-01
期刊：
影响因子：
8.3
通讯作者：
Annunziato, Lucio
中科院分区：
文献类型：
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作者：
Boscia, Francesca;Gala, Rosaria;Annunziato, Lucio
背景和目的-钠-钙交换剂NCX 1代表在缺氧条件下维持[Na +]（i）和[Ca 2 +]（i）的关键介体。迄今为止，没有关于缺血条件下小胶质细胞中NCX1蛋白表达和活性的信息。方法-通过Western印迹法、膜片钳电生理学、单细胞Fura-2乙酰氧基甲基酯显微荧光测定法、免疫组织化学和共聚焦显微镜，我们研究了脑内小胶质细胞中NCX1蛋白的区域和时间变化，永久性大脑中动脉闭塞后梗死区和核心区。交换器的表达和活性进行了测定，在原代小胶质细胞分离离体从成年大鼠大脑的核心区域7天后永久性大脑中动脉闭塞和在培养的小胶质细胞在体外hypoxia.Results-一天后永久性大脑中动脉闭塞，NCX1蛋白表达检测到一些小胶质细胞相邻的索马的神经元在梗死的核心。更有趣的是，大脑中动脉永久性闭塞后3天和7天，侵袭梗死核心的圆形小胶质细胞中的NCX1信号强烈增加。从核心获得的培养的小胶质细胞也显示出增加的NCX1表达与对侧细胞相比，并显示出增强的NCX活性的反向操作模式。类似地，NCX活性和NCX1蛋白表达在暴露于氧和葡萄糖剥夺的BV2小胶质细胞中显著增强，而NCX2和NCX3下调。有趣的是，在NCX1沉默的细胞，[Ca2 +]（i）缺氧诱导的增加是完全prevented.Conclusion-永久性大脑中动脉闭塞后，在小胶质细胞中观察到的NCX1的表达和活性的上调表明，NCX1在调制小胶质细胞的功能在postischemic脑的相关作用。（中风。2009; 40：3608 - 3617）。
Background and Purpose - The sodium - calcium exchanger NCX1 represents a key mediator for maintaining [Na+](i) and [Ca2+](i) in anoxic conditions. To date, no information is available on NCX1 protein expression and activity in microglial cells under ischemic conditions.Methods - By means of Western blotting, patch-clamp electrophysiology, single-cell Fura-2 acetoxymethyl-ester microfluorometry, immunohistochemistry, and confocal microscopy, we investigated the regional and temporal changes of NCX1 protein in microglial cells of the peri-infarct and core regions after permanent middle cerebral artery occlusion. The exchanger expression and activity were measured in primary microglia isolated ex vivo from the core region of adult rat brains 7 days after permanent middle cerebral artery occlusion and in cultured microglia under in vitro hypoxia.Results - One day after permanent middle cerebral artery occlusion, NCX1 protein expression was detected in some microglial cells adjacent to the soma of neurons in the infarct core. More interestingly, 3 and 7 days after permanent middle cerebral artery occlusion, NCX1 signal strongly increased in the round-shaped microglia invading the infarct core. Cultured microglial cells obtained from the core also displayed increased NCX1 expression as compared with contralateral cells and showed enhanced NCX activity in the reverse mode of operation. Similarly, NCX activity and NCX1 protein expression were significantly enhanced in BV2 microglia exposed to oxygen and glucose deprivation, whereas NCX2 and NCX3 were downregulated. Interestingly, in NCX1-silenced cells, [Ca2+](i) increase induced by hypoxia was completely prevented.Conclusion - The upregulation of NCX1 expression and activity observed in microglia after permanent middle cerebral artery occlusion suggests a relevant role of NCX1 in modulating microglia functions in the postischemic brain. (Stroke. 2009; 40: 3608-3617.)