Animal Models of P. Vera

真性红细胞增多症(PV)是一种原因不明的克隆性疾病，起源于多能造血者。 一种祖细胞，其特征是表型正常的红细胞、白细胞和 在没有明确原因的情况下出现血小板。血小板生成素受体MPL表达受损。 在PV中发生，在较小程度上，特发性骨髓纤维化(IM)和原发性血小板增多症(ET)，而在 非裔美国人，MPL点突变(K39N)与血小板增多症有关。最近，一台JAK2 点突变(V617F)在大多数PV患者中被发现，在部分IM和ET患者中也被发现。 这些分子异常中的每一个对PV表型的贡献程度及其 彼此之间的关系是未知的，但我们假设两者都有贡献，而且是整体相关的。 使用PV外周血CD34细胞中的基因表达谱和非监督分级聚类， 我们还能够将PV患者分为两组：患有侵袭性疾病的患者和 那些更懒惰的人。这些基因表达谱是否反映了 CD34细胞及其与JAK2 V617F突变的关系尚不清楚。为了解决这些问题，我们 计划建立互补的小鼠模型来研究小鼠的体外和体内行为 单独或联合使用MPL表达PV变异体MPL或JAK2 V617F的造血祖细胞 分析MPL和JAK2 V617F相互作用的基因敲除小鼠。控制MPL或MPL的过度表达 JAK2 V617F，我们还计划通过在小鼠ES细胞中的条件表达来检测它们的行为 MPL基因敲除鼠标。为了研究基因表达谱的功能意义，我们计划 研究PV CD34细胞的植入动力学、其谱系特异性定位及其程度 NOD-SCID小鼠移植后的髓外造血。使用流式细胞术和 对于异种移植，我们还计划通过免疫表型来确定参与PV的CD34细胞的类别。 PV并不是一种新疾病，但经过11年的研究，其病因仍不清楚， 目前还没有特效的治疗方法。我们建议为PV开发互补的动物模型，这将导致 为了了解PV的发病机制，这将确定PV患者最有可能患病 并发症，并为测试这种疾病的潜在治疗方法提供了一种手段。

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.