Xrcc1在体细胞诱导重编程过程中的作用及分子调控机制研究

系统深入的解析体细胞诱导重编程的调控机理，对诱导多能干细胞（iPS）安全的临床应用意义重大。我们通过已建立的体细胞连续六次诱导重编程体系，揭示了点突变的积累与DNA损伤修复中BER通路以及iPS发育潜能之间的相互调控关系，初步发现BER通路的调节基因Xrcc1促进体细胞诱导重编程，但其在该过程中的作用及机制尚不清楚。因此，本项目中，将首先明确Xrcc1对iPS的产生效率和质量的作用。其次，从诱导重编程中几个重要事件着手，如早期细胞增殖与凋亡，中晚期pre-iPS到成熟iPS的转变，多能性基因的去甲基化等，揭示过表达Xrcc1对诱导重编程的调控机制。最后，研究Xrcc1可否替代传统OSKM因子。同时，从基因表达和甲基化的动态变化、转录因子、蛋白修饰水平上的多能性调控网络等来阐明其替代调控机制。本项目将为体细胞诱导重编程分子调控机制的认识提供新视角，对高效高质iPS的获得有重要指导意义。

It is significant to understand the molecular mechanism of transcription factor-mediated reprogramming for the application of regenerative medicine. Our previous study revealed the regulatory relations among accumulated single-nucleotide variations (SNVs), base excision repair (BER) and iPSC developmental potential using the system of sequentially reprogrammed iPSCs. We further observed that Xrcc1, the critical regulation factor in BER pathway, might play an important role in the process of reprogramming. However, the exact mechanism of Xrcc1 in transcription factor mediated reprogramming have not been explored. Therefore, following our previous results, we first aim to identify the effect on the iPSC induction efficiency and quality. Then, we intend to analyze the cell proliferation and apoptosis, the transition of pre-iPS to mature iPS, the demethylation of pluripotent genes, to reveal the mechanism of Xrcc1 overexpressed in the iPSCs induction. Most importantly, the preliminary data showed that Xrcc1 can replace Oct4 and initiate reprogramming in conjunction with Sox2, Klf4 and c-Myc. Furthermore, the molecule events involved the mechanism of Xrcc1 replacement will be investigated comprehensively and thoroughly in the present project. Overall, we anticipate that our study can provide a deeper understanding of somatic cell reprogramming from a new angle of view and ultimately enhance the generation of high quality and safety iPSCs.