KLF5诱导小鼠始发态多能性干细胞向滋养层干细胞转变的作用与机制研究

滋养外胚层（TE）对胚胎发育至关重要。滋养层干细胞（TSCs）是体外研究TE功能和机制的重要模型，可来源于胚胎分离以及对体细胞或原始态多能干细胞（naïve PSCs）的重编程。KLF家族转录因子在小鼠胚胎发育不同阶段特异性表达，其中KLF5在内细胞团和TE中都有表达，且对两者正常发育都是必需的，而KLF5对TE命运的调控机制尚不清楚。我们前期发现，KLF5高表达能将小鼠始发态（primed）PSCs重编程为TSCs。为了阐明KLF5诱导TSCs的机制，本项目拟利用单细胞转录组描绘重编程路径；通过分析染色质开放和基因组结合，阐明KLF5结合的靶基因特征；从结构域和相互作用蛋白角度，比较KLF5与naïve特异因子KLF2的差异，鉴定KLF5调控TSCs命运的分子基础。本研究将有助于深入理解KLF5在小鼠早期胚胎发育中的作用，开发获得TSCs的新的重编程技术，并有望后续应用于人的体系研究。

Trophectoderm (TE) is critical for embryonic development. Trophoblast stem cells (TSCs) are important models for studying the functions and molecular mechanisms of TE in vitro, and they could not only be isolated from embryos, but also be obtained from reprogramming of somatic cells or naïve pluripotent stem cells (PSCs). Krüppel-like factor (KLF) family transcription factors are specifically expressed in different stages of mouse embryogenesis. Among them, KLF5 is expressed in both inner cell mass and TE, and is necessary for their development, but the mechanisms of KLF5 in TE fate regulation remains unclear. Intriguingly, we have recently discovered that KLF5 overexpression can induce reprogramming of mouse primed PSCs into TSCs. In order to clarify how KLF5 drives the TSCs induction, we aim to: 1, depict the roadmap of the reprogramming by single-cell transcriptomics; 2, find out KLF5 target genes through analyzing genome-wide chromatin accessibility and its binding sites; 3, uncover the molecular basis of how KLF5 regulates TSC cell fate by comparing to naïve specific factor KLF2, from the perspective of the domains and the interacting proteins. This study will enable a deeper understanding of KLF5 functions in early embryogenesis, and also help to establish a new reprogramming method to induce TSCs, which holds great promise for future human studies.