Mitochondrial DNA damage is more extensive and persists longer than nuclear DNA damage in human cells following oxidative stress
Mitochondrial DNA damage is more extensive and persists longer than nuclear DNA damage in human cells following oxidative stress
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DOI：
10.1073/pnas.94.2.514
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发表时间：
1997-01-21
影响因子：
11.1
通讯作者：
VanHouten, B
中科院分区：
文献类型：
--
作者：
Yakes, FM;VanHouten, B
线粒体氧化磷酸化过程中产生大量活性氧（ROS）。本研究采用定量PCR技术检测了线粒体16.2kb片段和β-珠蛋白基因侧翼17.7kb片段的过氧化氢诱导的DNA损伤的形成和修复，用200 μ M过氧化氢处理15或60分钟的猿猴病毒40转化的成纤维细胞表现出3倍以上的损害线粒体基因组相比，核片段。处理60分钟后，核碎片的损伤在1.5小时内完全修复，而在线粒体中没有观察到DNA修复。（4，5-二甲基噻唑-2-基）-2，5-二苯基溴化四唑还原，也显示急剧下降，这些细胞显示细胞生长受阻，p21蛋白水平大幅增加，与此相反，当过氧化氢处理限于15分钟时，线粒体DNA损伤以与核碎片相似的动力学修复，线粒体功能恢复，并且细胞在12小时内恢复分裂。这些结果表明线粒体DNA是ROS的关键细胞靶点，提出了一种模型，其中慢性ROS暴露，发现在几种退行性疾病与衰老相关，导致线粒体功能下降，增加神经元产生的ROS，和持续的线粒体DNA损伤。因此，持续的线粒体DNA损伤可以作为ROS相关疾病的有用生物标志物。
A significant amount of reactive oxygen species (ROS) is generated during mitochondrial oxidative phosphorylation. Several studies have suggested that mtDNA may accumulate more oxidative DNA damage relative to nuclear DNA, This study used quantitative PCR to examine the formation and repair of hydrogen peroxide-iuduced DNA damage in a 16.2-kb mitochondrial fragment and a 17.7-kb fragment flanking the beta-globin gene, Simian virus 40-transformed fibroblasts treated with 200 mu M hydrogen peroxide for 15 or 60 min exhibited 3-fold more damage to the mitochondrial genome compared with the nuclear fragment. Following a 60-min treatment, damage to the nuclear fragment was completely repaired within 1.5 hr, whereas no DNA repair in the mitochondrion was observed, Mitochondrial function, as assayed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide reduction, also showed a sharp decline, These cells displayed arrested-cell growth, large increases in p21 protein levels, and morphological changes consistent with apoptosis, In contrast, when hydrogen peroxide treatments were limited to 15 min, mtDNA damage was repaired with similar kinetics as the nuclear fragment, mitochondrial function was restored, and cells resumed division within 12 hr, These results indicate that mtDNA is a critical cellular target for ROS, A model is presented in which chronic ROS exposure, found in several degenerative diseases associated with aging, leads to decreased mitochondrial function, increased mitochondrial-generated ROS, and persistent mitochondrial DNA damage. Thus persistent mitochondrial DNA damage may serve as a useful biomarker for ROS-associated diseases.