Transient mitochondrial permeability transition mediates excitotoxicity in glutamate-sensitive NSC34D motor neuron-like cells.
Transient mitochondrial permeability transition mediates excitotoxicity in glutamate-sensitive NSC34D motor neuron-like cells.
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DOI：
10.1016/j.expneurol.2015.05.010
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发表时间：
2015-09
影响因子：
5.3
通讯作者：
Wang W
中科院分区：
文献类型：
--
作者：
Liu X;Xu S;Wang P;Wang W
兴奋性毒性在神经退行性疾病中起着至关重要的作用。胞质钙超载和线粒体功能障碍是高水平谷氨酸诱导的神经元死亡的主要介质之一。在这里，我们发现线粒体通透性转换孔（tMPT）的短暂开放桥接了细胞质钙信号传导和线粒体功能障碍，并介导谷氨酸诱导的神经元死亡。将分化的运动神经元样 NSC34D 细胞与谷氨酸 (1 mM) 一起孵育会急剧诱导胞质钙瞬变（增加 30%）。谷氨酸还刺激 tMPT 打开，表现为超氧化物闪现频率增加 2 倍，超氧化物闪现是单个线粒体中与 tMPT 打开相关的超氧化物爆发事件。谷氨酸诱导的 tMPT 打开可通过抑制胞质钙内流来减弱，并通过用 Ru360 (100 µM) 或 MCU shRNA 抑制线粒体钙单向转运蛋白 (MCU) 来消除。此外，增加的胞质钙足以以线粒体钙依赖性方式诱导 tMPT。最后，长期谷氨酸孵育（24 小时）持续提高 tMPT 打开的可能性，促进氧化应激并诱导神经元死亡。减弱 tMPT 活性或抑制 MCU 可保护 NSC34D 细胞免受谷氨酸诱导的细胞死亡。这些结果表明，高水平谷氨酸诱导的神经元毒性是由 tMPT 介导的，tMPT 将增加的胞质钙信号与线粒体功能障碍联系起来。
Excitotoxicity plays a critical role in neurodegenerative disease. Cytosolic calcium overload and mitochondrial dysfunction are among the major mediators of high level glutamate-induced neuron death. Here, we show that the transient opening of mitochondrial permeability transition pore (tMPT) bridges cytosolic calcium signaling and mitochondrial dysfunction and mediates glutamate-induced neuron death. Incubation of the differentiated motor neuron-like NSC34D cells with glutamate (1 mM) acutely induces cytosolic calcium transient (30% increase). Glutamate also stimulates tMPT opening, as reflected by a 2-fold increase in the frequency of superoxide flash, a bursting superoxide production event in individual mitochondria coupled to tMPT opening. The glutamate-induced tMPT opening is attenuated by suppressing cytosolic calcium influx and abolished by inhibiting mitochondrial calcium uniporter (MCU) with Ru360 (100 µM) or MCU shRNA. Further, increased cytosolic calcium is sufficient to induce tMPT in a mitochondrial calcium dependent manner. Finally, chronic glutamate incubation (24 hr) persistently elevates the probability of tMPT opening, promotes oxidative stress and induces neuron death. Attenuating tMPT activity or inhibiting MCU protects NSC34D cells from glutamate-induced cell death. These results indicate that high level glutamate-induced neuron toxicity is mediated by tMPT, which connects increased cytosolic calcium signal to mitochondrial dysfunction.