染色质重塑子INO80在心肌谱系决定中的作用及其机制研究

Understanding the molecular basis of human pluripotent stem cell (hPSC) differentiation is key to their clinical application. Previous studies revealed a critical role of signaling pathways in cardiac lineage commitment, however, how chromatin structure are regulated to dictate specific gene expression programs in this process remains largely unknown. Our preliminary results displayed that Ino80, a core component of INO80 chromatin remodeling complex, was specifically expressed in developing hearts of mice, and that Ino80 silencing dramatically compromised cardiac differentiation from human embryonic stem cells (hESCs). Based on these observations, we hypothesize that INO80 plays an essential role in cardiac lineage commitment, and therefore is an intriguing target that can be exploited to regulate cardiac differentiation. To test our hypothesis, we will first confirm the role of INO80 in hESC differentiation, and uncover the underlying mechanisms by genomic approaches. Then, we will build and test the molecular network of INO80-regulated cardiac lineage commitment by integrating the genomic data of INO80 and other key factors implicated in this process. Finally, we will identify the key subunits of INO80 responsible for cardiac lineage commitment by immunoprecipitation followed by mass-spectrometry (IP-MS), and explore the possibility to improve cardiac differentiation by manipulating the subunit(s). Findings from this study will provide insights into how chromatin factors coordinate with other factors to determine cell fates, and will offer novel strategies to enhance the efficiency of cardiac differentiation from PSCs.

人多能干细胞的应用取决于我们对其定向分化分子机制的理解。以往研究揭示信号通路在心肌谱系决定中发挥着重要作用，但染色质结构如何被调节以控制该过程中特定基因表达程序却尚未阐明。我们发现INO80染色质复合物的关键亚基Ino80在胚胎小鼠心脏特异性表达，敲低该亚基抑制人胚胎干细胞向心肌细胞分化。据此推测，INO80在心肌谱系决定中发挥着重要作用，并可能成为调控心肌细胞分化的靶点。为验证此假设，拟首先在人胚胎干细胞分化中确定INO80的作用，并进一步通过基因组学方法明确其作用机制；接着整合INO80和其它心肌谱系决定中关键因子的基因组学数据，构建并验证INO80调控这一过程的分子网络；最后通过质谱分析等方法寻找该复合物中调控心肌谱系决定的关键亚基，并探讨通过操控此亚基促进心肌细胞分化的可能性。本研究将帮助我们理解染色质因子如何协同其它因子决定细胞命运，并为促进多能干细胞向心肌细胞分化提供新的策略。

人多能干细胞的应用取决于我们对其定向分化分子机制的理解。以往研究揭示信号通路在心肌谱系决定中发挥着重要作用，但染色质结构如何被调节以控制该过程中特定基因表达程序却尚未阐明。我们发现INO80染色质复合物的关键亚基Ino80在胚胎小鼠心脏特异性表达，敲低该亚基抑制人胚胎干细胞向心肌细胞分化。接着揭示了INO80的动态占位与分化过程中的心肌发育高度相关、并且激活靶基因的转录表达。进一步研究发现INO80复合物在分化中有着不同的亚基组成并且与BRG1相互作用调控其下游靶基因的表达。本研究将帮助我们理解染色质因子如何协同其它因子决定细胞命运，并为促进多能干细胞向心肌细胞分化提供新的策略。