Chronic oxidative stress compromises telomere integrity and accelerates the onset of senescence in human endothelial cells
Chronic oxidative stress compromises telomere integrity and accelerates the onset of senescence in human endothelial cells
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DOI：
10.1242/jcs.01097
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发表时间：
2004-05-01
影响因子：
4
通讯作者：
Erusalimsky, JD
中科院分区：
文献类型：
--
作者：
Kurz, DJ;Decary, S;Erusalimsky, JD
复制性衰老和氧化应激与衰老、内皮功能障碍和动脉粥样硬化有关。复制性衰老主要由端粒完整性决定。在内皮细胞中，谷胱甘肽氧化还原循环在过氧化物的解毒中起主要作用。本研究的目的是阐明依赖谷胱甘肽的抗氧化系统对培养内皮细胞的复制能力和端粒动力学的作用。人脐静脉内皮细胞连续传代，同时暴露于0.1 muM叔丁基过氧化氢（谷胱甘肽过氧化物酶的底物）或10 muM l -丁硫氨酸-[S，R]-亚砜胺（谷胱甘肽合成抑制剂）的常规处理下。两种处理均诱导细胞内氧化应激，但没有细胞毒性或细胞抑制作用。尽管如此，通过衰老相关的β -半乳糖苷酶染色和融合时细胞密度的急剧下降可以确定，处理过的培养物过早进入衰老（30对46倍）。在氧化应激的培养中，末端限制性片段（TRF）分析表明，端粒缩短速度更快（110 bp/倍于55 bp/倍），并且在15-20倍以上的群体翻倍后出现明显的长TRF。中期扩散的荧光原位杂交分析证实了端粒长度异质性的增加，并排除了端粒端到端融合作为长TRFs来源的可能性。后者也被基因组DNA的Bal31消化所证实。同样，端粒酶的上调不能解释长TRFs的出现，因为氧化应激诱导了端粒酶活性的快速和持续下降。这些发现证明了谷胱甘肽依赖的氧化还原稳态在内皮细胞端粒功能保存中的关键作用，并表明端粒完整性的丧失是轻度慢性氧化应激下过早衰老的主要触发因素。
Replicative senescence and oxidative stress have been implicated in ageing, endothelial dysfunction and atherosclerosis. Replicative senescence is determined primarily by telomere integrity. In endothelial cells the glutathione redox-cycle plays a predominant role in the detoxification of peroxides. The aim of this study was to elucidate the role of the glutathione-dependent antioxidant system on the replicative capacity and telomere dynamics of cultured endothelial cells. Human umbilical vein endothelial cells were serially passaged while exposed to regular treatment with 0.1 muM tert-butyl hydroperoxide, a substrate of glutathione peroxidase, or 10 muM L-buthionine-[S,R]-sulphoximine, an inhibitor of glutathione synthesis. Both treatments induced intracellular oxidative stress but had no cytotoxic or cytostatic effects. Nonetheless, treated cultures entered senescence prematurely (30 versus 46 population doublings), as determined by senescence-associated beta-galactosidase staining and a sharp decrease in cell density at confluence. In cultures subjected to oxidative stress terminal restriction fragment (TRF) analysis demonstrated faster telomere shortening (110 versus 55 bp/population doubling) and the appearance of distinct, long TRFs after more than 15-20 population doublings. Fluorescence in situ hybridisation analysis of metaphase spreads confirmed the presence of increased telomere length heterogeneity, and ruled out telomeric end-to-end fusions as the source of the long TRFs. The latter was also confirmed by Bal31 digestion of genomic DNA. Similarly, upregulation of telomerase could not account for the appearance of long TRFs, as oxidative stress induced a rapid and sustained decrease in this activity. These findings demonstrate a key role for glutathione-dependent redox homeostasis in the preservation of telomere function in endothelial cells and suggest that loss of telomere integrity is a major trigger for the onset of premature senescence under mild chronic oxidative stress.