Bioenergetic dysfunction in Huntington's disease human cybrids
Bioenergetic dysfunction in Huntington's disease human cybrids
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DOI：
10.1016/j.expneurol.2011.05.024
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发表时间：
2011-09-01
影响因子：
5.3
通讯作者：
Cristina Rego, A.
中科院分区：
文献类型：
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作者：
Luisa Ferreira, I.;Cunha-Oliveira, Teresa;Cristina Rego, A.
在这项工作中，我们研究了亨廷顿病（HD）与对照（CTR）细胞系中线粒体相关的代谢途径，这是一种分离患者线粒体缺陷的细胞模型。与CTR杂交体相比，HD杂交体表现出ATP水平的有趣增加。同时，我们观察到HD杂交体的糖酵解率增加，这表明乳酸/丙酮酸比增加，糖酵解抑制后又恢复。HD杂交体中葡萄糖-6-磷酸脱氢酶活性的降低进一步表明戊糖-磷酸途径的速率降低。糖酵解抑制显著降低了HD杂交体的ATP水平，并伴有磷酸肌酸的降低。然而，补充丙酮酸不能恢复HD杂交体的ATP或磷酸肌酸水平，这表明线粒体对该底物的使用功能障碍。寡霉素还导致ATP水平下降，提示线粒体部分支持ATP生成。然而，HD杂交体线粒体NADH/NAD(t)水平降低，这与丙酮酸脱氢酶活性和蛋白表达降低有关，表明糖酵解过程中三羧酸循环（TCA）输入减少。有趣的是，α -酮戊二酸脱氢酶（一种连接TCA与氨基酸合成和降解的关键酶复合体）的活性在HD杂交体中增加。线粒体谷氨酸水平升高，丙氨酸水平降低，而天冬氨酸和谷氨酰胺水平不变。相反，在HD杂交体中，总细胞提取物的苹果酸脱氢酶活性没有变化。我们的研究结果表明，HD患者线粒体的固有功能障碍会影响细胞核功能背景下的细胞生物能量学。(C) 2011爱思唯尔公司版权所有。
In this work we studied the mitochondrial-associated metabolic pathways in Huntington's disease (HD) versus control (CTR) cybrids, a cell model in which the contribution of mitochondrial defects from patients is isolated. HD cybrids exhibited an interesting increase in ATP levels, when compared to CTR cybrids. Concomitantly, we observed increased glycolytic rate in HD cybrids, as revealed by increased lactate/pyruvate ratio, which was reverted after inhibition of glycolysis. A decrease in glucose-6-phosphate dehydrogenase activity in HD cybrids further indicated decreased rate of the pentose-phosphate pathway. ATP levels of HD cybrids were significantly decreased under glycolysis inhibition, which was accompanied by a decrease in phosphocreatine. Nevertheless, pyruvate supplementation could not recover HD cybrids' ATP or phosphocreatine levels, suggesting a dysfunction in mitochondrial use of that substrate. Oligomycin also caused a decrease in ATP levels, suggesting a partial support of ATP generation by the mitochondria. Nevertheless, mitochondrial NADH/NAD(t) levels were decreased in HD cybrids, which was correlated with a decrease in pyruvate dehydrogenase activity and protein expression, suggesting decreased tricarboxylic acid cycle (TCA) input from glycolysis. Interestingly, the activity of alpha-ketoglutarate dehydrogenase, a critical enzyme complex that links the TCA to amino acid synthesis and degradation, was increased in HD cybrids. In accordance, mitochondrial levels of glutamate were increased and alanine was decreased, whereas aspartate and glutamine levels were unchanged in HD cybrids. Conversely, malate dehydrogenase activity from total cell extracts was unchanged in HD cybrids. Our results suggest that inherent dysfunction of mitochondria from HD patients affects cellular bioenergetics in an otherwise functional nuclear background. (C) 2011 Elsevier Inc. All rights reserved.