ASIC CHANNEL INHIBITION ENHANCES EXCITOTOXIC NEURONAL DEATH IN AN IN VITRO MODEL OF SPINAL CORD INJURY
ASIC CHANNEL INHIBITION ENHANCES EXCITOTOXIC NEURONAL DEATH IN AN IN VITRO MODEL OF SPINAL CORD INJURY
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DOI：
10.1016/j.neuroscience.2016.12.008
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发表时间：
2017-02-20
期刊：
影响因子：
3.3
通讯作者：
Uchitel, Osvaldo D.
中科院分区：
文献类型：
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作者：
Mazzone, Graciela L.;Veeraraghavan, Priyadharishini;Uchitel, Osvaldo D.
在脊髓中，高细胞外谷氨酸引起兴奋性毒性损伤，伴有神经元丢失和严重的运动障碍。在细胞功能障碍过程中，细胞外pH变为酸性，并可能激活酸敏感离子通道（ASIC），这可能是神经退行性病变的重要贡献者。我们以前的研究表明，短暂应用谷氨酸类似物红藻氨酸（KA）引起脊髓神经元的延迟兴奋性毒性死亡，而白色物质主要是幸免。目前的目标是询问ASIC通道是否调制KA损伤与运动网络功能和细胞死亡有关。用KA（0.01或0.1 mM）处理小鼠脊髓切片1小时，然后在分析前冲洗24小时。RT-PCR结果显示，KA（在接近损伤阈值的0.01 mM浓度下）增加了ASIC 1a、ASIC 1b、ASIC 2和ASIC 3的mRNA表达，ASIC抑制剂4 '，6-diamidino-2-phe nylindole（DAPI）逆转了这种作用。KA神经毒性剂量（0.1 mM）降低ASIC 1a和ASIC 2表达。细胞活力测定表明KA诱导ASIC 1a基因消融小鼠脊髓切片的大损伤。同样，免疫组织化学表明，当KA后的ASIC抑制剂DAPI或阿米洛利显着的神经元损失。离体脊髓前根的电生理记录显示，0.01 mM KA会减慢交替振荡周期，并被随后应用的DAPI或阿米洛利强烈抑制。我们的数据表明，ASIC表达和功能的早期上升抵消了脊髓网络的有害影响，提高兴奋性毒性阈值，结果与改善神经保护的潜在影响。(C)2016年IBRO。由爱思唯尔有限公司出版。保留所有权利。
In the spinal cord high extracellular glutamate evokes excitotoxic damage with neuronal loss and severe locomotor impairment. During the cell dysfunction process, extracellular pH becomes acid and may activate acid sensing ion channels (ASICs) which could be important contributors to neurodegenerative pathologies. Our previous studies have shown that transient application of the glutamate analog kainate (KA) evokes delayed excitotoxic death of spinal neurons, while white matter is mainly spared. The present goal was to enquire if ASIC channels modulated KA damage in relation to locomotor network function and cell death. Mouse spinal cord slices were treated with KA (0.01 or 0.1 mM) for 1 h, and then washed out for 24 h prior to analysis. RT-PCR results showed that KA (at 0.01 mM concentration that is near-threshold for damage) increased mRNA expression of ASIC1a, ASIC1b, ASIC2 and ASIC3, an effect reversed by the ASIC inhibitor 4',6-diamidino-2-phe nylindole (DAPI). A KA neurotoxic dose (0.1 mM) reduced ASIC1a and ASIC2 expression. Cell viability assays demonstrated KA-induced large damage in spinal slices from mice with ASIC1a gene ablation. Likewise, immunohistochemistry indicated significant neuronal loss when KA was followed by the ASIC inhibitors DAPI or amiloride. Electrophysiological recording from ventral roots of isolated spinal cords showed that alternating oscillatory cycles were slowed down by 0.01 mM KA, and intensely inhibited by subsequently applied DAPI or amiloride. Our data suggest that early rise in ASIC expression and function counteracted deleterious effects on spinal networks by raising the excitotoxicity threshold, a result with potential implications for improving neuroprotection. (C) 2016 IBRO. Published by Elsevier Ltd. All rights reserved.