Koopman Werner J H, Visch Henk-Jan, Verkaart Sjoerd, van den Heuvel Lambertus W P J, Smeitink Jan A M, Willems Peter H G M
Microscopical Imaging Cente, Nijmegen Center for Mitochondrial Disorders, The Netherlands.
Am J Physiol Cell Physiol. 2005 Oct;289(4):C881-90. doi: 10.1152/ajpcell.00104.2005. Epub 2005 May 18.
Complex I (NADH:ubiquinone oxidoreductase) is the largest multisubunit assembly of the oxidative phosphorylation system, and its malfunction is associated with a wide variety of clinical syndromes ranging from highly progressive, often early lethal, encephalopathies to neurodegenerative disorders in adult life. The changes in mitochondrial structure and function that are at the basis of the clinical symptoms are poorly understood. Video-rate confocal microscopy of cells pulse-loaded with mitochondria-specific rhodamine 123 followed by automated analysis of form factor (combined measure of length and degree of branching), aspect ratio (measure of length), and number of revealed marked differences between primary cultures of skin fibroblasts from 13 patients with an isolated complex I deficiency. These differences were independent of the affected subunit, but plotting of the activity of complex I, normalized to that of complex IV, against the ratio of either form factor or aspect ratio to number revealed a linear relationship. Relatively small reductions in activity appeared to be associated with an increase in form factor and never with a decrease in number, whereas relatively large reductions occurred in association with a decrease in form factor and/or an increase in number. These results demonstrate that complex I activity and mitochondrial structure are tightly coupled in human isolated complex I deficiency. To further prove the relationship between aberrations in mitochondrial morphology and pathological condition, fibroblasts from two patients with a different mutation but a highly fragmented mitochondrial phenotype were fused. Full restoration of the mitochondrial network demonstrated that this change in mitochondrial morphology was indeed associated with human complex I deficiency.
复合体I（NADH：泛醌氧化还原酶）是氧化磷酸化系统中最大的多亚基组件，其功能异常与多种临床综合征相关，从高度进展性、通常早期致死性的脑病到成人期的神经退行性疾病。作为临床症状基础的线粒体结构和功能变化尚不清楚。对用线粒体特异性罗丹明123脉冲加载的细胞进行视频速率共聚焦显微镜观察，随后自动分析形状因子（长度和分支程度的综合测量）、纵横比（长度测量）和数量，结果显示13例孤立性复合体I缺陷患者的皮肤成纤维细胞原代培养物之间存在明显差异。这些差异与受影响的亚基无关，但将复合体I的活性（以复合体IV的活性标准化）与形状因子或纵横比与数量的比值作图，显示出线性关系。相对较小的活性降低似乎与形状因子增加相关，且从未与数量减少相关，而相对较大的活性降低则与形状因子降低和/或数量增加相关。这些结果表明，在人类孤立性复合体I缺陷中，复合体I活性与线粒体结构紧密相关。为了进一步证明线粒体形态异常与病理状况之间的关系，将两名具有不同突变但线粒体高度碎片化表型的患者的成纤维细胞进行融合。线粒体网络的完全恢复表明，这种线粒体形态变化确实与人类复合体I缺陷相关。
