Animal Models of P. Vera

真性红细胞增多症（PV）是一种病因不明的克隆性疾病，发生于多能造血干细胞系统。 祖细胞，其特征在于过量产生表型正常的红细胞、白色细胞和 血小板在没有明确的原因。血小板生成素受体Mpl. 发生于PV，在较小程度上发生于特发性骨髓纤维化（IM）和原发性血小板增多症（ET），而在 在非裔美国人中，Mpl点突变（K39 N）与血小板增多症相关。近日，一架JAK 2 点突变（V617 F）在大多数PV患者中发现，也在一些IM和ET患者中发现。 这些分子异常中的每一种对PV表型的贡献程度及其对PV表型的影响。 彼此之间的关系是未知的，但我们假设两者都有贡献，并且是整体相关的。 使用PV外周血CD 34+细胞的基因表达谱和无监督分层聚类， 我们还能够将PV患者分为两组：侵袭性疾病患者和 那些更懒惰的人。这些基因表达谱是否反映了细胞的功能行为， CD 34+细胞及其与JAK 2 V617 F突变的关系尚不清楚。为了解决这些问题，我们 计划开发互补的小鼠模型，以研究小鼠的体外和体内行为， 单独或一起使用Mpl表达PV变体Mpl或JAK 2 V617 F的造血祖细胞 敲除小鼠以剖析Mpl和JAK 2 V617 F相互作用。为了控制Mpl或 JAK 2 V617 F，我们还计划在小鼠ES细胞中使用条件表达来检查它们的行为， Mpl敲除小鼠。为了研究基因表达谱的功能意义，我们计划 研究PV CD 34+细胞的植入动力学、其谱系特异性定型以及 移植到NOD-SCID小鼠后的髓外造血。使用流式细胞术和 在异种移植中，我们还计划通过免疫表型确定PV中涉及的CD 34+细胞的类别。 PV不是一种新疾病，但经过11年的研究，其病因仍然未知， 目前尚无特效治疗方法。我们建议开发PV的补充动物模型， 了解PV的发病机制，这将确定PV患者的疾病风险最大 并发症，并提供了一种用于测试该疾病的潜在治疗方法的手段。

Polycythemia vera (PV) is a clonal disorder of unknown etiology arising in a multipotent hematopoietic progenitor cell that is characterized by overproduction of phenotypically normal red cells, white cells and platelets in the absence of a definable cause. Impaired expression of the thrombopoietin receptor, Mpl. occurs in PV and to a lesser extent, idiopathic myelofibrosis (IM) and essential thrombocytosis (ET), while in African Americans, an Mpl point mutation (K39N) was associated with thrombocytosis. Recently, a JAK2 point mutation (V617F) was identified in the majority of PV patients and also in some IM and ET patients. The extent to which each of these molecular abnormalities contributes to the PV phenotype and their relationship to each other is unknown but we hypothesize that both contribute and are integrally related. Using gene expression profiling and unsupervised hierarchical clustering in PV peripheral blood CD34+ cells, we have also been able to segregate PV patients into two groups: those with an aggressive disease and those with a more indolent one. Whether these gene expression profiles reflect the functional behavior of the CD34+ cells and how they relate to the JAK2 V617F mutation is unknown. To address these questions, we plan to develop complementary murine models to study the in vitro and in vivo behavior of murine hematopoietic progenitor cells expressing PV variant Mpl or JAK2 V617F alone or together using the Mpl knockout mouse to dissect Mpl and JAK2 V617F interactions. To control for overexpression of either Mpl or JAK2 V617F, we also plan to examine their behavior using conditional expression in murine ES cells from the Mpl knockout mouse. To examine the functional significance of the gene expression profiles, we plan to study the engraftment kinetics of PV CD34+ cells, their lineage-specific commitment and the extent of extramedullary hematopoiesis after transplantation into NOD-SCID mice. Using flow cytometry and xenotransplantation, we also plan to define by immunophenotyping, the class of CD34+ cell involved in PV. PV is not a new disease but after 11 decades of investigation, its etiology remains unknown and there is no specific therapy for it. We propose to develop complementary animal models for PV that will lead to an understanding of the pathogenesis of PV, that will identify PV patients most at risk from disease complications, and provide a means for testing potential treatments for the disorder.