C/EBPε缺失在骨髓增生异常/骨髓增殖性肿瘤发病中的作用及机制研究

CAAT/enhancer-binding protein epsilon (C/EBPε) is to be known an important transcription factor for regulating terminate differentiation of granulocyte, which controls the formation and function of granules in granulocytes. Recently, our study found that C/EBPε deletion in mice blocks immature myeloid differentiation and impairs erythoid development in bone marrow as well as leads to extramedullary hemopoiesis in spleen, suggesting C/EBPε deletion in mice developed Myelodysplastic/myeloproliferative neoplasms (MDS/MPN). We plan to study the function of C/EBPε deletion stem/progenitors on MDS/MPN development by transplantation assay. Next, we plan to find the direct downstream targets of C/EBPε by performing ChIP-seq, RNA-seq and further verification experiments on myeloid progenitor cells from C/EBPε deletion and control mice. Furthermore, we plan to verify whether C/EBPε and its direct downstream targets of MDS/MPN patients have mutation, deletion, gene silence and abnormal methylation modifications. Our study will find the new pathogenesis of MDS/MPN, and be the basis for precision design new target treatments.

C/EBPε被认为是重要的调控粒细胞终末分化的转录因子，可控制粒细胞颗粒的形成和功能，而我们最近的研究发现C/EBPε基因敲除小鼠的骨髓髓系祖细胞分化障碍，红系发育阻滞，脾脏出现髓外造血，显示C/EBPε缺失的小鼠发生了骨髓增生异常/骨髓增殖性肿瘤（MDS/MPN）。本项目将进一步通过骨髓移植实验，探索C/EBPε缺失的干/祖细胞在MDS/MPN发病中的作用；分选对照和C/EBPε 敲除小鼠的髓系祖细胞亚群，通过ChIP-seq、RNA-seq以及相关的分析和验证实验，揭示小鼠C/EBPε下游的靶基因；在MDS/MPN病人标本中，验证C/EBPε基因及其下游关键靶基因是否有突变、缺失、基因沉默和甲基化修饰异常。本研究将发现MDS/MPN发病的新机制，为精准设计针对MDS/MPN的靶向治疗新方案奠定基础。

C/EBPε是重要的调控粒细胞终末分化的真核转录因子，可控制粒细胞中颗粒的形成和功能，已发现它在先天免疫的炎症反应中发挥重要的作用。在对C／EBPε敲除鼠的研究中，我们首次发现敲除C/EBPε的小鼠髓系祖细胞分化障碍，红系发育阻滞，脾脏出现髓外造血，最终发生骨髓增生异常/骨髓增殖性肿瘤（MDS/MPN）。为了探索C/EBPε缺失造成小鼠新表型的分子机制，我们进行了染色质免疫共沉淀测序（ChIP-seq）检测。除了已知的C/EBPε和DNA结合位点(ATTGnnCAAT)外，我们通过Motif分析发现了新的DNA结合位点(GTTGnnCAAC)，并通过电泳迁移率变动分析(EMSA)、定量RT-PCR等实验证明了C/EBPε可直接调控与MDS/MPN发生密切相关的 Pten、IL-1β等下游靶基因的启动子区域。此外，在初发MDS/MPN 病人骨髓细胞样本中也发现了C/EBPε存在新的突变位点（CEBPεp.Thr151Ser），本研究为探索MDS/MPN的发病新机制和靶向治疗新途径奠定了基础。