低氧诱导红系造血相关microRNAs的筛选和调控机制研究

Hypoxia is the principal regulator of erythropoiesis. The response to hypoxia is controlled by hypoxia-inducible factor-1a (HIF-1a) transcriptional factor. The role of microRNA in regulation of erythropoiesis is currently being defined. However, little is known about the definitive regulatory mechanism of hypoxia-induced erythropoiesis through HIF-1a and microRNA. High-altitude polycythemia (HAPC) is a typical disease as the model in the researches on hypoxia-induced erythropoiesis. Therefore, we analyzed microRNA gene expression profile of sorted erythroid cells of bone marrow and found there were three microRNAs contributing to hypoxia-induced erytropoiesis in HAPC. Furthermore, we perform the research to discover the total microRNAs profile of erythroid cells both from HAPC patients and cord blood-derived CD34 cells in hypoxia, and to demonstrate the hypoxia-HIF-1a-erthropoiesis axis.

低氧通过HIF-1α诱导红系分化是红系造血的关键调控机制之一。但是，关于低氧通过microRNA调控红系造血的研究鲜有报道，且机制不明。高原红细胞增多症（HAPC）是低氧对红系造血调控的经典体现，选择其作为研究对象可以更好地阐明低氧条件下的红系造血机制。我们的前期研究提示，HAPC患者骨髓红系细胞存在差异表达的microRNA，值得进一步探讨。本课题旨在前期研究的基础上，免疫磁珠分选HAPC患者的骨髓红系细胞和脐血CD34+细胞定向诱导分化的红系细胞（低氧），通过高通量技术检测红系细胞的microRNA表达谱。试图展示低氧诱导红系造血相关microRNA谱；筛选低氧影响红系造血的关键microRNA、靶基因和关键信号通路，通过抑制或过表达HIF-1α观察microRNA和下游靶基因变化，进行低氧-HIF-1α-microRNA-红系特异基因表达轴研究，阐述低氧环境下红系造血的调控机制。

低氧通过HIF-1α诱导红系分化是红系造血的关键调控机制之一。但是，关于低氧通过microRNA调控红系造血的研究鲜有报道，且机制不明。高原红细胞增多症（HAPC）是低氧对红系造血调控的经典体现，选择其作为研究对象可以更好地阐明低氧条件下的红系造血机制。本课题组通过免疫磁珠分选HAPC患者的骨髓红系CD235a+细胞，应用高通量分析技术分析并红系细胞的microRNA表达谱，扩大样本验证发现hsa-miR-363是低氧通过HIF-1α调控红系造血的重要microRNA。然后与K562细胞株实验相结合，证实低氧-HIF-1α-hsa-miR-363-红系特异基因（GATA-1、FOG-1和β-globin）表达轴在低氧诱导红系造血过程中发挥着重要的调控作用。为进一步探讨microRNAs在低氧诱导红系造血和高原红细胞增多症发病机制中的作用提供了重要的线索，为后续的纵向深入研究奠定基础。