Mitochondrial DNA damage as a mechanism of cell loss in Alzheimer's disease
Mitochondrial DNA damage as a mechanism of cell loss in Alzheimer's disease
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DOI：
10.1038/labinvest.3780140
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发表时间：
2000-08-01
影响因子：
5
通讯作者：
Wands, JR
中科院分区：
文献类型：
--
作者：
de la Monte, SM;Luong, T;Wands, JR
衰老与由氧自由基诱导的线粒体（Mt）DNA突变积累引起的线粒体功能受损有关。一种流行的理论是，与年龄相关的疾病，包括阿尔茨海默病（AD），可能是由线粒体功能受损引起、传播或引起的。为了研究MtDNA相对于基因组（Gn）DNA损伤在AD中的作用，分析了来自死后AD（n = 37）和对照（n = 25）脑的颞叶样品的MtDNA和GnDNA片段化、线粒体蛋白和细胞色素氧化酶表达、MitoTracker绿色荧光（以评估线粒体质量/丰度）和8-氧代-7，8-二氢-2 '-脱氧鸟苷（8-OHdG）免疫反应性。与AD的大脑有更广泛的切口和MtDNA和GnDNA片段的琼脂糖凝胶电泳，末端标记，和原位末端脱氧核苷酸转移酶末端标记（TUNEL）分析表明，只有与AD的大脑有可检测的8-OHdG免疫反应在皮层神经元。AD中MtDNA损伤增加与MtDNA含量降低相关，如半定量PCR分析和Mt蛋白和细胞色素氧化酶表达水平降低（Western印迹分析或免疫组织化学染色结合图像分析）所示。AD脑中MitoTracker绿色荧光减少的发现提供了额外的证据，即AD神经变性发生Mt质量/丰度减少。AD中MtDNA和GnDNA损伤增加的存在表明AD中存在双重细胞死亡级联。由MtDNA损伤引起的线粒体功能受损可能使AD中的脑细胞更容易受到氧化损伤，从而提供全身或环境因素可能影响疾病进程的机制。
Aging is associated with impaired mitochondrial function caused by accumulation of oxygen free radical-induced mitochondrial (Mt) DNA mutations. One prevailing theory is that age-associated diseases, including Alzheimer's disease (AD), may be precipitated, propagated, or caused by impaired mitochondrial function. To investigate the role of MtDNA relative to genomic (Gn) DNA damage in AD, temporal lobe samples from postmortem AD (n = 37) and control (n = 25) brains were analyzed for MtDNA and GnDNA fragmentation, mitochondrial protein and cytochrome oxidase expression, MitoTracker Green fluorescence (to assess mitochondrial mass/abundance), and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-OHdG) immunoreactivity. Brains with AD had more extensive nicking and fragmentation of both MtDNA and GnDNA as demonstrated by agarose gel electrophoresis, end-labeling, and the in situ terminal deoxynucleotide transferase end-labeling (TUNEL) assay, and only the brains with AD had detectable 8-OHdG immunoreactivity in cortical neurons. Increased MtDNA damage in AD was associated with reduced MtDNA content, as demonstrated by semiquantitative PCR analysis and reduced levels of Mt protein and cytochrome oxidase expression by Western blot analysis or immunohistochemical staining with image analysis. The finding of reduced MitoTracker Green fluorescence in AD brains provided additional evidence that reduced Mt mass/abundance occurs with AD neurodegeneration. The presence of increased MtDNA and GnDNA damage in AD suggest dual cell death cascades in AD. Impaired mitochondrial function caused by MtDNA damage may render brain cells in AD more susceptible to oxidative injury and thereby provide a mechanism by which systemic or environmental factors could influence the course of disease.