构建原发性和继发性红细胞增多症动物模型及巨噬细胞参与红系造血作用机制研究

Activated EPO receptor (EPOR) signaling causes erythrocytosis. Primary erythrocytosis is developed by an EPO-independent, erythroid cellintrinsic mechanism due to constitutively activated EPOR signaling by gain-of function EPOR orJAK2 mutations. To mimic the chimeric condition and expansion of the disease clone in the polycythemia vera patients, we combine Cre-inducible Jak2 V617F/+ allele with LysM-Cre allele which expresses in mature myeloid cells and some of the HSC/Ps (LysM-Cre/Jak2V617F/+ mice). We also generate inducible EPO-mediated secondary erythrocytosis model using Alb-Cre, Rosa26-loxP-stoploxP-rtTA, and doxycycline inducible EPAS1-double point mutant (DPM) alleles (Alb-Cre/DPMmice). The important role of macrophages for the erythroid expansion and differentiation process has been reported, both in baseline and stress erythropoiesis. However, the significance of EPOR signaling for regulation of macrophages contributing to erythropoiesis has not been fully understood. Based on our new erythocytosis mouse models, we will investigate the central role of macrophages in erythropoiesis under EPOR signaling activation.

促红细胞生成素受体（EPOR）信号通路是调节红细胞生成的重要因素。由于红细胞内在缺陷（EPOR突变或JAK2 V617F）导致非EPO依赖性红细胞增多。为了真实模拟PV患者体内JAK2 V617F与正常克隆嵌合存在的状态以及监测突变克隆的演变，我们拟通过LysM-Cre在成熟粒、单核细胞及部分造血干、祖细胞（HSC/HPC）表达Jak2 V617F，构建LysM-Cre/Jak2 V617F/+原发性红细胞增多模型；EPAS1是调控EPO基因表达的重要蛋白，我们通过构建包含P531和N847双突变位点EPAS1-DPM小鼠，与Alb-Cre小鼠和Rosa26LSL-rtTA小鼠杂交，获得Alb-Cre/DPM小鼠。通过DOX在肝脏诱导EPAS1持续、稳定表达，构建新的继发性红细胞增多症模型。 在上述模型基础上，进一步研究EPOR信号通路活化对红系和巨噬细胞作用机制。

促红细胞生成素受体（EPOR）信号通路是调节红细胞生成的重要因素。由于红细胞内在缺陷（EPOR突变或JAK2 V617F）导致非EPO依赖性红细胞增多。本课题预期内完成 .LysM-Cre/Jak2 V617F/+原发性红细胞增多小鼠及对照小鼠模型的建立，以真实模拟PV患者体内JAK2 V617F与正常克隆嵌合存在的状态；完成DOX诱导肝脏特异性表达EPAS1双突变的Alb-Cre/DPM继发性红细胞增多小鼠及对照小鼠模型的建立；构建 EPOR/ROSAmT/mG 小鼠模型并完成其表型鉴定。本课题的创新点在于：发现高表达VCAM1的组织特异性巨噬细胞通过trogocytosis，协同EPOR信号的激活，促进红系生成。