体细胞通过转入特定的转录因子重编程为诱导多功能干细胞（induced pluripotent stem cells, iPSCs）过程中伴随着端粒的延长和端粒酶的激活，iPSCs端粒的不稳定性会对其生物学特性的产生影响，目前有关iPSCs诱导和增殖过程中端粒复制的调控机制还不清楚。 Werner’s病人体细胞存在端粒复制功能缺陷。本研究拟选择Werner’s综合征病人皮肤成纤维细胞诱导iPSCs, 对比分析正常组、Werner’s组和转入hTERT组体细胞重编程过程中和诱导所得iPSCs的端粒长短的变化、端粒酶活性变化,及相关基因表达和诱导分化过程中基因稳定性的改变。探讨Werner’s iPS端粒代谢有无异常及其发生机制；同时观察hTERT能否全部或部分修复WRN基因缺陷导致的重编程障碍和iPSCs生物学特性异常。

Reprogramming of somatic cells to induced pluripotent stem cell by defined factors elongates telomere, activates TERT, and is associated with the acquisition of self-renewal capacity. Variations of telomere length in different iPSC lines have been reported, especially in premature disease specific iPSCs. However, mechanisms of telomere length regulation during induction and proliferation of iPSCs remain elusive. Werner’s syndrome (WS) is due to WRN single gene defect, and is a premature aging syndrome characterized by early onset of age-related pathologies and cancer. Telomere metabolism dysfunction plays one of most important role in WS’s Pathophysiology. In this study, we will generate WS patient-specific iPSCs using non-integrate viral vectors. An inducible vector of human telomerase reverse transcriptase (hTERT) will be introduced to WS’s fibroblast to increase reprogramming rate. Telomere length and telomerase activity of iPSCs derived from Werner’s, Werner’s with inducible hTERT, control, and control with inducible hTERT will be analyzed. Related gene expression and genome DNA stability will also be analyzed to explore the mechanism of telomere metabolism in WS’S iPSCs. The objectives of this proposal is to detect whether there is any difference between WS’s iPSCs and normal iPSCs, what is the mechanism of WS’s telomere dynamics, and whether hTERT could compensate for telomere deficiency in WS’s somatic cell reprogramming process and iPSC’s characteristics.