2i调控Dux促进小鼠胚胎干细胞分化潜能的分子机制研究

2i（Meki和Gsk3βi）有利于维持小鼠胚胎干细胞的原始态多能性。然而，近期却有研究发现，长期2i处理可导致不可逆的染色体及表观遗传改变，并削弱细胞体内发育潜能。但是这些研究却存在诸多问题，例如将体系中多个变量的置换，仅归结于2i的作用；缺乏客观、可定量的体内发育潜能研究；未进行多组细胞系比较研究等。申请人长期从事细胞多能性的表观遗传调控机制研究，相关研究成果发表在Nature和Cell Stem Cell（封面）等杂志。申请人前期研究已初步证明2i对转录组及表观遗传的改变是可逆的，且进一步发现了2i调控细胞多能性的一条潜在的新型调控途径。本研究将通过建立可定量分化潜能分析系统并结合多组学技术，在控制变量的基础上，系统阐明短期和长期2i处理对胚胎干细胞多能性的真正影响, 揭示2i通过抑制Dux引起的2C基因激活，从而促进小鼠胚胎干细胞体内分化的分子机制。

Inhibitors of Mek1/2 and Gsk3β, known as 2i, promote ground-state pluripotency of mouse embryonic stem cells (mESCs), whereas recent studies have found prolonged 2i treatment results in irreversible epigenetic and genomic changes that impair developmental potential of mESCs. However, there are certain problems in these studies. For example, the substitution of multiple variables in the culture system was only attributed to the role of 2i; there lacked objective and quantifiable studies of in vivo developmental potential of mESCs; there was no comparative study of multiple groups of cell lines. Over the past few years, the applicant’s research field was mainly focused on the epigenetic regulation of pluripotency and these scientific works have been published in journals such as Nature and Cell Stem Cell (cover article). The applicant’s preliminary studies have shown that the transcriptome and epigenetic changes caused by 2i are reversible, and a new regulatory pathway for 2i in regulating pluripotency is being revealed. In the present study, we will make full use of our newly established quantifiable in vivo differentiation analysis system and advanced multi-omics technologies, so as to systematically clarify the true impact of 2i on pluripotency of mESCs. In addition, we will reveal the molecular mechanism of how 2i promoting in vivo differentiation potential of mESCs by inhibiting Dux-induced 2C gene activation.