G37R SOD1 mutant alters mitochondrial complex I activity, Ca2+ uptake and ATP production
G37R SOD1 mutant alters mitochondrial complex I activity, Ca2+ uptake and ATP production
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DOI：
10.1016/j.ceca.2011.02.004
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发表时间：
2011-04-01
期刊：
影响因子：
4
通讯作者：
Callewaert, Geert
中科院分区：
文献类型：
--
作者：
Coussee, Evelyne;De Smet, Patrick;Callewaert, Geert
肌萎缩侧索硬化症（amyotrophiclateralsclerosis，ALS）是一种以运动神经元选择性死亡为特征的神经退行性疾病。铜/锌超氧化物歧化酶-1（SOD 1）突变导致家族性ALS，但这些突变诱导运动神经元死亡的分子机制仍有争议。在这里，我们表明，稳定过表达突变型人SOD 1（G37 R）-而不是野生型SOD 1（wt-SOD 1）-在小鼠神经母细胞瘤细胞（N2 a）的结果在形态异常的线粒体伴随着几个功能障碍。氧化磷酸化复合物I的活性在G37 R细胞中显著降低，并且与较低的线粒体膜电位和降低的胞浆ATP水平相关。使用靶向嵌合水母发光蛋白，我们进一步分析了线粒体功能障碍对细胞Ca 2+处理的后果。线粒体Ca 2+摄取，引起IP 3诱导的Ca 2+释放内质网（ER）中的G37 R细胞显着减少，而吸收诱导的短暂的Ca 2+脉冲在透性细胞不受影响。线粒体Ca 2+摄取减少导致胞浆Ca 2+瞬变增加，而ER Ca 2+负荷和静息胞浆Ca 2+水平不受影响。总之，这些发现表明，突变体G37 R SOD 1和ALS的机制涉及线粒体呼吸链缺陷，导致ATP损失和线粒体和胞质Ca 2+稳态受损。(C)2011爱思唯尔有限公司保留所有权利。
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by selective death of motor neurons. Mutations in Cu/Zn superoxide dismutase-1 (SOD1) cause familial ALS but the molecular mechanisms whereby these mutations induce motor neuron death remain controversial. Here, we show that stable overexpression of mutant human SOD1 (G37R) - but not wild-type SOD1 (wt-SOD1)- in mouse neuroblastoma cells (N2a) results in morphological abnormalities of mitochondria accompanied by several dysfunctions. Activity of the oxidative phosphorylation complex I was significantly reduced in G37R cells and correlated with lower mitochondrial membrane potential and reduced levels of cytosolic ATP. Using targeted chimeric aequorin we further analyzed the consequences of mitochondrial dysfunction on cellular Ca2+ handling. Mitochondrial Ca2+ uptake, elicited by IP3-induced Ca2+ release from endoplasmic reticulum (ER) was significantly reduced in G37R cells, while uptake induced by a brief Ca2+ pulse was not affected in permeabilized cells. The decreased mitochondrial Ca2+ uptake resulted in increased cytosolic Ca2+ transients, whereas ER Ca2+ load and resting cytosolic Ca2+ levels were not affected. Together, these findings suggest that the mechanism linking mutant G37R SOD1 and ALS involves mitochondrial respiratory chain deficiency resulting in ATP loss and impairment of mitochondrial and cytosolic Ca2+ homeostasis. (C) 2011 Elsevier Ltd. All rights reserved.