Concentration dependent effect of calcium on brain mitochondrial bioenergetics and oxidative stress parameters.
Concentration dependent effect of calcium on brain mitochondrial bioenergetics and oxidative stress parameters.
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DOI：
10.3389/fnene.2013.00010
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发表时间：
2013-01-01
期刊：
影响因子：
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通讯作者：
Sullivan, Patrick G
中科院分区：
文献类型：
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作者：
Pandya, Jignesh D;Nukala, Vidya N;Sullivan, Patrick G
创伤性脑和脊髓损伤（TBI 和 SCI）后的线粒体功能障碍在继发性病理生理学和随后的神经细胞死亡的发展中起着关键作用。此前，我们证明了 TBI 和 SCI 后最初 24 小时内线粒体生物能的丧失，在原发损伤部位引发了快速而广泛的坏死事件。在线粒体衍生机制中，兴奋性毒性、Ca(2+)循环/过载、ATP合成、自由基产生和氧化损伤过程之间的串扰和不平衡最终导致线粒体损伤，随后导致神经元细胞死亡。线粒体是调节细胞内钙(Ca(2+))稳态的重要细胞器之一，并配备有严格调节的Ca(2+)转运系统。然而，由于在已发表的文献中缺乏共识以及钙的下游影响之间的联系，我们进行了一项系统的体外研究，测量钙（100-1000 nmols/mg线粒体蛋白）对线粒体呼吸、酶活性、活性氧/氮（ROS/RNS）生成、膜电位（DeltaPsi）和分离脑线粒体中氧化损伤标记物的浓度依赖性影响。我们观察到钙对线粒体呼吸的剂量和时间依赖性抑制，而不影响线粒体丙酮酸脱氢酶复合物（PDHC）和NADH脱氢酶（复合物I）的酶活性。我们观察到钙产生的过氧化氢和总 ROS/RNS 物种的产生呈剂量依赖性下降，并且蛋白质和脂质氧化损伤标记物没有显着变化。这些结果可能为钙对线粒体生物能学、自由基产生和氧化应激参数的直接影响的普遍教条提供新的启示，这些参数是神经元损伤后主要的线粒体调节机制。
Mitochondrial dysfunction following traumatic brain and spinal cord injury (TBI and SCI) plays a pivotal role in the development of secondary pathophysiology and subsequent neuronal cell death. Previously, we demonstrated a loss of mitochondrial bioenergetics in the first 24 h following TBI and SCI initiates a rapid and extensive necrotic event at the primary site of injury. Within the mitochondrial derived mechanisms, the cross talk and imbalance amongst the processes of excitotoxicity, Ca(2+) cycling/overload, ATP synthesis, free radical production and oxidative damage ultimately lead to mitochondrial damage followed by neuronal cell death. Mitochondria are one of the important organelles that regulate intracellular calcium (Ca(2+)) homeostasis and are equipped with a tightly regulated Ca(2+) transport system. However, owing to the lack of consensus and the link between downstream effects of calcium in published literature, we undertook a systematic in vitro study for measuring concentration dependent effects of calcium (100-1000 nmols/mg mitochondrial protein) on mitochondrial respiration, enzyme activities, reactive oxygen/nitrogen species (ROS/RNS) generation, membrane potential (DeltaPsi) and oxidative damage markers in isolated brain mitochondria. We observed a dose- and time-dependent inhibition of mitochondrial respiration by calcium without influencing mitochondrial pyruvate dehydrogenase complex (PDHC) and NADH dehydrogenase (Complex I) enzyme activities. We observed dose-dependent decreased production of hydrogen peroxide and total ROS/RNS species generation by calcium and no significant changes in protein and lipid oxidative damage markers. These results may shed new light on the prevailing dogma of the direct effects of calcium on mitochondrial bioenergetics, free radical production and oxidative stress parameters that are primary regulatory mitochondrial mechanisms following neuronal injury.