Telomere dysfunction in human keratinocytes elicits senescence and a novel transcription profile
Telomere dysfunction in human keratinocytes elicits senescence and a novel transcription profile
复制标题
DOI：
10.1016/j.yexcr.2008.05.007
复制
发表时间：
2008-08-01
影响因子：
3.7
通讯作者：
Parkinson, E. Kenneth
中科院分区：
文献类型：
--
作者：
Minty, Fay;Thurlow, Johanna K.;Parkinson, E. Kenneth
研究表明，端粒脱落会导致正常人类成纤维细胞衰老，并导致淋巴细胞和p53敏感癌细胞凋亡。然而，端粒脱帽对正常上皮细胞的影响以前没有被研究过。我们已经使用表征良好的端粒重复结合因子2（TRF2）显性阴性突变体TRF2（Delta B Delta M）来消耗正常人表皮角质形成细胞（NHEK）的TRF2端粒。我们观察到仅在丝氨酸15和53BP1 DNA损伤灶处p53磷酸化增加了两倍，而p21（WAF）未检测到增加。尽管DNA损伤反应较弱，但角化细胞生长停滞，显示集落形成减少和衰老。小的、流产的衰老菌落在48小时内没有融入Brd-U，表达衰老相关的β -半乳糖苷酶（sa - β -gal）。trf2缺失的角质形成细胞的转录谱显示了几个基因的可重复上调。这些包括组蛋白，与DNA损伤和角化细胞终末分化相关的基因。一些相同的基因也被证明在角化细胞经历自然端粒介导的衰老时上调，而在异位端粒酶表达时下调。因此，这项研究揭示了端粒功能障碍的高度敏感和特异性候选指标，可能用于识别衰老、癌症和其他疾病中端粒介导的角质细胞衰老。(c) 2008爱思唯尔公司版权所有。
The uncapping of telomeres has been shown to precipitate senescence in normal human fibroblasts and apoptosis in lymphocytes and p53-competent cancer cell lines. However, the effects of telomere uncapping on normal epithelial cells have not previously been examined. We have used the well characterised telomere repeat binding factor 2 (TRF2) dominant-negative mutant, TRF2(Delta B Delta M), to deplete Normal Human Epidermal Keratinocytes (NHEK) telomeres of TRF2. We observed only a two fold increase in both phosphorylation of p53 at serine 15 and 53BP1 DNA damage foci and no detectable increase in p21(WAF). Despite the weak DNA damage response, the keratinocytes growth arrest, demonstrate reduced colony formation and senescence. The small, abortive senescent colonies did not incorporate Brd-U within 48 h and expressed senescence-associated beta galactosidase (SA-beta-gal). Transcriptional profiling of TRF2-depleted keratinocytes showed a reproducible up-regulation of several genes. These included histones, genes associated with DNA damage and keratinocyte terminal differentiation. Several of the same genes were also shown to be up-regulated when keratinocytes undergo natural telomere-mediated senescence and down-regulated by ectopic telomerase expression. This study has thus revealed highly sensitive and specific candidate indicators of telomere dysfunction that may find use in identifying telomere-mediated keratinocyte senescence in ageing, cancer and other diseases. (c) 2008 Elsevier Inc. All rights reserved.