非编码RNA H19通过cohesin复合体调控白血病发病的功能和机制研究

Understand the mechanism of leukemogenesis and treatment is critical for curing leukemia in clinic. Previously the applicant has systematically investigated the function and mechanism of Rig-I in leukemogenesis (PNAS 2011, Mol Cell 2014). The applicant recently found that loss of non-coding RNA H19 can promote leukemogenesis in MLL-AF9 model but did not impair normal HSC function. To understand the molecular mechanisms the applicant performed RNA pulldown combined with mass spectrometry and found that H19 is associated with multiple component proteins of cohesion complex. Furthermore, Chromatin isolation by RNA purification (ChIRP) assay showed that H19 is associated with cohesin protein Smc3 and CTCF, which regulates chromatin 3D architecture. This indicated that H19 might be involved in chromatin 3D architecture for transcriptional regulation during leukemogenesis. In this proposal, the applicant will investigate the role of H19 in other types of leukemia and use established chromosome conformation capture (Hi-C) to understand how H19 regulates chromatin 3D architecture in leukemogenesis. This accomplishment will clarify the in vivo function of non-coding RNA, which has crucial influence in both basic research and clinic trial.

解析白血病发病和治疗的分子机制是临床白血病治疗的关键科学问题。申请人前期通过研究RIG-I的功能阐述其在维甲酸治疗白血病中的作用机制(PNAS 2011, Mol Cell 2014)。近期预实验结果发现非编码RNA H19敲除小鼠造血干细胞功能正常，但在MLL-AF9白血病模型中白血病干细胞数量明显增加且发病进程加快，并且H19敲除导致多个白血病发病相关基因表达改变。已知cohesin复合体通过调节染色体结构和状态影响基因的转录表达，并与白血病发病密切相关。申请人进一步发现H19 RNA可以与cohesin复合体相互作用，且H19在染色体上的结合与cohesin蛋白具有相关性。申请人将深入研究H19通过cohesin复合体调控多种白血病发病的作用并通过功能筛选和组学技术探讨相关机制。这些研究有望揭示非编码RNA调控白血病发病的体内功能和新的调控机制，具有重要的基础和临床意义。

急性髓系白血病（AML）是髓系细胞恶性增生和分化受阻导致的恶性血液肿瘤，目前的主要治疗方法是化疗，但是病人的预后很差，五年生存率在20%以下。因此急切需要寻找白血病治疗的有效靶点来提高AML病人的生存率。我们发现长链非编码RNA H19通过影响白血病干细胞的干性促进AML发病，敲除H19能够增强AML对放疗和化疗的敏感性，H19下游主要通过JAK-STAT3通路影响白血病的发病和治疗。本项目的研究成果证实了H19可能作为新的治疗靶点用于临床白血病患者的治疗，为提高放、化疗的临床疗效和提高白血病治愈率提供新的理论支持。