Somatic Mitochondrial DNA Deletions Accumulate to High Levels in Aging Human Extraocular Muscles
Somatic Mitochondrial DNA Deletions Accumulate to High Levels in Aging Human Extraocular Muscles
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DOI：
10.1167/iovs.09-4660
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发表时间：
2010-07-01
影响因子：
4.4
通讯作者：
Turnbull, Douglass M.
中科院分区：
文献类型：
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作者：
Yu-Wai-Man, Patrick;Lai-Cheong, Joey;Turnbull, Douglass M.
目的。研究人员对从不同年龄范围的个体中收集的眼外肌 (EOM) 进行了线粒体功能和体细胞线粒体 DNA (mtDNA) 缺陷的研究，以记录正常衰老过程中观察到的变化。方法。对 46 个 EOM 样本进行细胞色素 C 氧化酶 (COX) 和琥珀酸脱氢酶 (SDH) 组织化学分析，以确定连续低温恒温器肌肉切片中 COX 缺乏的水平（平均年龄，42.6 岁；范围，3.0-96.0 岁）。对单纤维裂解物进行竞争性三引物和实时 PCR，以检测和量化 mtDNA 缺失。还进行了全基因组线粒体测序，以评估 mtDNA 点突变对总体突变负荷的贡献。 结果。 COX 阴性纤维在 30 岁开始出现在 EOM 中，并且与年龄相关的显着增加：60 岁，3.34%（n = 16，P = 0.0001）。在所有三个年龄组中，EOM 中的 COX 缺乏水平也高于骨骼肌中的水平 (P < 0.0001)。大多数COX阴性纤维具有高水平（>70%）mtDNA缺失（206/284，72.54%），平均缺失水平为66.64%（SD 36.45%）。全线粒体基因组测序的突变率相对较低（1/19，5.3%），在低缺失水平的 COX 阴性纤维中仅发现单个 mtDNA 点突变
PURPOSE. Mitochondrial function and the presence of somatic mitochondrial DNA (mtDNA) defects were investigated in extraocular muscles (EOMs) collected from individuals covering a wide age range, to document the changes seen with normal aging.METHODS. Cytochrome c oxidase (COX) and succinate dehydrogenase (SDH) histochemistry was performed on 46 EOM samples to determine the level of COX deficiency in serial cryostat muscle sections (mean age, 42.6 years; range, 3.0-96.0 years). Competitive three-primer and real-time PCR were performed on single-fiber lysates to detect and quantify mtDNA deletions. Whole-genome mitochondrial sequencing was also performed to evaluate the contribution of mtDNA point mutations to the overall mutational load.RESULTS. COX-negative fibers were seen in EOMs beginning in the third decade of life, and there was a significant age-related increase: 60 years, 3.34% (n = 16, P = 0.0001). Higher levels of COX deficiency were also present in EOM than in skeletal muscle in all three age groups (P < 0.0001). Most of the COX-negative fibers harbored high levels (>70%) of mtDNA deletions (206/284, 72.54%) and the mean deletion level was 66.64% (SD 36.45%). The mutational yield from whole mitochondrial genome sequencing was relatively low (1/19, 5.3%), with only a single mtDNA point mutation identified among COX-negative fibers with low deletion levels