高原红细胞增多症中GATA-1调控红系分化相关microRNAs的筛选及机制研究

High altitude polycythemia (HAPC) is characterized by excessive accumulation of erythrocytes and severe hypoxemia, which often leads to a variety of complications with high mortality, and the pathogenesis of it is unkown. Previous studies suggest that GATA-1 promotes normal erythroid differentiation by regulating many downstream erythroid related target genes. Moreover, GATA-1 provides accurate regulation of erythroid differentiation through the targeting of miRNA. Research results afterwards show that GATA-1 is involved in normal erythroid differentiation by regulating the expression of miRNA-451 etc. In our early work, we find that the expression of GATA-1 in CD71+ cells was abnormally increased in HAPC model rats. To further clarify the importance of transcriptional activation of miRNA by GATA-1 in the pathogenesis of HAPC, we aim to establish the erythroid differentiation model of hypoxic K562 cells and HAPC CD34+ cells, analysing expression profile of miRNA in the process of erythroid differentiation of K562 cells in hypoxia by miRNA expression chip. With the expression of significantly upregulated miRNA by potential regulation of GATA-1 as the starting point, the project is aiming to explore the expression trends and regulation relationship of GATA-1 and miRNA in the HAPC patients, and furthermore to explain the role of GATA-1 in the regulation of miRNA in the development of HAPC.

高原红细胞增多症(HAPC)以红细胞过度积累、严重低氧血症为特征，常引发致死率较高的并发症，发病机制不明。既往研究表明，GATA-1调控众多下游红系相关靶基因，促进正常红系分化过程。其中，GATA-1通过靶向miRNA，实现对红系分化的精细调控。近期研究结果显示，GATA-1调节miRNA-451等的表达，参与正常红系分化。本课题组前期发现HAPC模型大鼠CD71+细胞中GATA-1表达异常增高，为明确GATA-1对miRNA的转录激活在HAPC发病机制中的作用，本项目拟建立低氧下K562细胞和HAPC患者CD34+细胞红系分化模型，应用miRNA表达芯片分析低氧K562细胞向红系分化过程中miRNA的差异表达，以受GATA-1潜在调控并表达明显上调的miRNA为切入点，探讨HAPC患者GATA-1和miRNA的表达趋势及调控关系，阐释GATA-1调控miRNA在HAPC发生发展中的作用。

红系特异性转录调节因子GATA-1可通过靶向miRNAs，实现对红系分化的精细调控。本课题应用miRNA表达芯片分析了低氧K562细胞向红系分化过程中miRNAs的差异表达，获得124个备选miRNAs。以受GATA-1潜在调控并表达明显上调的miRNA-451a、miRNA-210-3p为切入点，检测了低氧下K562细胞和高原红细胞增多症（HAPC）患者CD34+细胞红系分化模型中，GATA-1和miRNA-451a、miRNA-210-3p的表达趋势及调控关系，结果显示GATA-1和miRNA-451a、miRNA-210-3p受低氧影响，表达量明显增高；GATA-1/miR-451a/14-3-3ζ正向调控红系分化过程；GATA-1可与miR-210-3p的启动子区域直接结合，低氧下GATA-1上调miR-210-3p的表达水平，间接下调Smad2的表达可能促进红系分化。综合上述结果，本研究为探讨GATA-1调控miRNA-451a、miRNA-210-3p在HAPC发生发展中的作用机制奠定了坚实的工作基础，同时对于认知miRNA-451a、miRNA-210-3p对HAPC红系细胞异常分化的影响提供了启示性线索。