Wtap通过调控c-Myc的m6A修饰维持造血干细胞静息态平衡的机制研究

维持造血干细胞（HSC）静息态平衡对机体正常造血功能至关重要，HSC静息态失衡可能导致白血病的发生。申请人前期利用造血系统特异性敲除m6A甲基转移酶复合体亚基Wtap的小鼠模型开展研究时发现，Wtap缺失导致小鼠HSC数目显著增多，但处于静息态的HSC比例降低，自我更新能力严重受损，提示Wtap具有维持HSC静息态平衡的重要作用。转录组数据显示Wtap缺失小鼠中多个与细胞增殖和周期相关的通路上调表达。多组学关联分析及实验发现，c-Myc的m6A修饰水平和转录水平均显著下调。同时c-Myc下游参与细胞周期调控的细胞周期蛋白依赖性激酶抑制因子表达显著下调。因此，提出Wtap可能通过调控c-Myc的m6A修饰维持HSC静息态平衡的科学假说。本课题拟从动物、细胞及分子水平阐明Wtap调控HSC静息态的分子机制，以期完善HSC静息态调控网络，并为白血病的防治提供新的思路。

Maintenance of hematopoietic stem cells (HSCs) quiescence is vital essential to the normal hematopoiesis, and breaking the balance of HSC quiescence may lead to leukemia occurrence. When we analyzed hematopoietic-specific knockout model to study the function of Wtap in regulating HSC, we found that Wtap deficiency led to a significant increase in HSC number, but a decrease in quiescent HSC proportion, and impaired HSC self-renew capacity. All the data indicates that Wtap plays an important role in the regulation of HSC quiescence. Transcriptome data showed multiple cell proliferation and cell cycle-related pathways were up-regulated in Wtap knockout mice. Multi-omics association analysis and experiment data showed that the m6A modification level and transcription level of c-Myc were significantly downregulated. Meanwhile, the expression of cell cycle-dependent kinase inhibitors involved in cell cycle regulation was significantly down-regulated. Therefore, we proposed that Wtap may maintain HSC quiescence by regulating the m6A modification of c-Myc. We intends to elucidate the molecular mechanism of Wtap regulating HSC quiescence using in vitro and in vivo models. The research generated by our project is important to interpret the function of RNA m6A modification in HSCs quiescence, and shed light on the prevention and treatment of leukemia.