Mitochondrial Ca2+ Processing by a Unit of Mitochondrial Ca2+ Uniporter and Na+/Ca2+ Exchanger Supports the Neuronal Ca2+ Influx via Activated Glutamate Receptors
Mitochondrial Ca2+ Processing by a Unit of Mitochondrial Ca2+ Uniporter and Na+/Ca2+ Exchanger Supports the Neuronal Ca2+ Influx via Activated Glutamate Receptors
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DOI：
10.1007/s11064-015-1819-3
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发表时间：
2016-06-01
影响因子：
4.4
通讯作者：
Reiser, Georg
中科院分区：
文献类型：
--
作者：
Strokin, Mikhail;Reiser, Georg
目前的研究表明，在海马神经元线粒体Ca 2+加工支持Ca 2+内流通过离子型谷氨酸（Glu）受体。我们将线粒体Ca ~（2+）加工定义为通过线粒体Ca ~（2+）单向转运体（MCU）摄取Ca ~（2+）并随后通过线粒体Na ~+/Ca ~（2+）交换体（NCX）释放Ca ~（2+）。我们的工具是通过荧光数字显微镜测量原代海马共培养物（即神经元和星形胶质细胞）中的Ca 2+内流率，使用Fura-2-猝灭方法，其中我们在灌流培养基中添加少量Mn 2+。因此，Ca 2+流入量与浴中的Mn 2+一起测量。Ru 360通过MCU作为线粒体Ca 2+摄取的抑制剂强烈地降低Glu刺激的原代海马神经元中的Ca 2+内流速率。同样，当我们用鱼藤酮去线粒体时，Glu刺激的神经元中的Ca 2+内流率在电位依赖性MCU抑制后下降。随着使用CGP-37157通过NCX抑制Ca 2+从线粒体释放，通过N-甲基-d-天冬氨酸（NMDA）和红藻氨酸敏感受体的Ca 2+内流减慢。MCU和NCX共同作为线粒体Ca ~（2+）处理单位，明显维持激活的Glu敏感受体的Ca ~（2+）通量。我们的研究结果修订的作用，经常归因于线粒体在神经元内Ca 2+的稳态，线粒体的功能主要是作为Ca 2+缓冲，并防止过高的胞质Ca 2+浓度增加在神经元的活动。在这项研究中发现，控制神经元中Ca 2+内流的机制突出了线粒体Ca 2+加工作为一个有前途的药理学靶点。我们讨论了这一途径有关的内质网相关的Ca 2+加工机制。
The current study demonstrates that in hippocampal neurons mitochondrial Ca2+ processing supports Ca2+ influx via ionotropic glutamate (Glu) receptors. We define mitochondrial Ca2+ processing as Ca2+ uptake via mitochondrial Ca2+ uniporter (MCU) combined with subsequent Ca2+ release via mitochondrial Na+/Ca2+ exchanger (NCX). Our tool is to measure the Ca2+ influx rate in primary hippocampal co-cultures, i.e. neurons and astrocytes, by fluorescent digital microscopy, using a Fura-2-quenching method where we add small amounts of Mn2+ in the superfusion medium. Thus, Ca2+ influx is measured with Mn2+ in the bath. Ru360 as inhibitor of mitochondrial Ca2+ uptake through MCU strongly reduces the rate of Ca2+ influx in Glu-stimulated primary hippocampal neurons. Similarly, the Ca2+ influx rate in Glu-stimulated neurons declines after suppression of potential-dependent MCU, when we depolarize mitochondria with rotenone. With inhibition of Ca2+ release from mitochondria via NCX using CGP-37157 the Ca2+ influx via N-methyl-d-aspartate (NMDA)- and kainate-sensitive receptors is slowed down. Working jointly as mitochondrial Ca2+ processing unit, MCU and NCX, apparently sustain the Ca2+ throughput of activated Glu-sensitive receptors. Our results revise the role frequently attributed to mitochondria in neuronal Ca2+ homeostasis, where mitochondria function mainly as Ca2+ buffer, and prevent excessively high cytosolic Ca2+ concentration increase during neuronal activity. The mechanism to control Ca2+ influx in neurons, as discovered in this study, highlights mitochondrial Ca2+ processing as a promising pharmacological target. We discuss this pathway in relation to the endoplasmic reticulum-related mechanisms of Ca2+ processing.