A New Murine Model for MPN: Pathololgy and Therapy of NF-E2 Overexpression

尽管最近我们对骨髓增生性肿瘤（mpn）的发展的理解有所进展，但这些疾病的病理生理学仍然知之甚少。特别是MPN患者转化为急性白血病的易感性尚不清楚。根据我们观察到转录因子核因子红系2 （NF-E2）在大多数MPN患者中过表达，我们通过在体内过表达NF-E2建立了MPN小鼠模型。除了JAK2 V617F和c-MpI W515X小鼠模型外，这是唯一一个在MPN患者中观察到分子畸变的MPN小鼠模型。NF-E2在包括造血祖细胞在内的所有造血谱系中均过表达。两条独立产生的方正线显示了MPNsj的许多特征，包括血小板增多、脾肿大和骨髓（BM）组织学上mpn样改变。NF-E2转基因（tg）小鼠的BM红系、髓系和巨核细胞前体数量显著增加，特别是自主的、不依赖于epo的红系集落数量显著增加。epo非依赖性菌落是MPN患者的病理特征。NF-E2转基因小鼠的死亡率显著增加，其尸检结果与MPN患者相似，包括内脏血栓形成和出血性糖尿病。在20个月大时，一只小鼠（7.6%）患上急性白血病。因此，我们的小鼠模型显示出与MPN的许多特征非常相似的表型。此外，我们的初步数据表明，NF-E2过表达可能易导致急性白血病的发展。基于这些数据，我们提出以下假设：假设1:NF-E2过表达改变造血干细胞（hsc），导致MPN表型的发展。NF-E2过表达引起造血干细胞的细胞自主变化，因此该表型可移植，并构成造血干细胞疾病。特异性目的1：进行一次和二次移植，并表征NF-E2转基因供体和受体小鼠的干细胞室。假设2:NF-E2过表达构成白血病前期状态，易进化为急性白血病。特异性目的2：用n -乙基-n -亚硝基脲ENU诱变剂治疗NF-E2转基因小鼠和对照小鼠，观察白血病转化频率。假设3:NF-E2过表达引起的病理生理变化可通过药物干预治疗。具体的

Despite recent advances in our understanding of the development of Myeloproliferative Neoplasms (MPNs), the pathophysiology of these disorders remains poorly understood. Especially the predisposition of MPN patients to transform to acute leukemia is not elucidated. Based on our observation that the transcription factor nuclear factor erythroid 2 (NF-E2) is overexpressed in the majority of MPN patients, we have established a murine model for MPNs, by overexpressing NF-E2 in vivo. Besides the JAK2 V617F and c-MpI W515X mouse models, this is the only murine model of MPN that employs a molecular aberration observed in MPN patients. NF-E2 was overexpressed in all hematopoietic lineages including hematopoietic progenitor cells. Two independently generated founder lines show a phenotype with many features of MPNsj including thrombocytosis, splenomegaly and MPN-like changes in bone marrow (BM) histology. The number of BM erythroid, myeloid and megakaryocytic precursors are significantly increased in NF-E2 transgenic (tg) mice, notably the number of autonomous, EPO-independent erythroid colonies. EPO-independent colonies are a pathognomonic hallmark of MPN patients. NF-E2 transgenic mice display significantly increased mortality with autopsy findings resembling those of MPN patients including splanchnic thrombosis and bleeding diatheses. At 20 months of age, one mouse (7.6%) developed acute leukemia. Our murine model therefore displays a phenotype closely resembling many features of MPN. In addition, our preliminary data indicate that NF-E2 overexpression may predispose to the development of acute leukemia. Based on this data, we formulate the following hypotheses: Hypothesis 1: NF-E2 overexpression alters hematopoietic stem cells (HSCs) resulting in the development of an MPN phenotype. NF-E2 overexpression causes cellautonomous changes in HSCs, the phenotype is therefore transplantable and constitutes a hematopoietic stem cell disorder. Specific Aim 1: To perform primary and secondary transplants and to characterize the stem cell compartment of NF-E2 transgenic donor and recipient mice. Hypothesis 2: NF-E2 overexpression constitutes a pre-leukemic state and predisposes to the evolution to acute leukemia. Specific Aim 2: To treat NF-E2 transgenic and control mice with the mutagen N-ethyl-N-nitrosourea ENU and observe the frequency of leukemic transformation. Hypothesis 3: The pathophysiological changes evoked by NF-E2 overexpression are treatable by pharmacologic intervention. Specific Aim 3: To treat NF-E2 transgenic mice with pharmacological agents currently in pre-clinical or phase I clinical trials for MPN patients.