Regulation of hematopoiesis by CUX1

项目总结 骨髓增生异常综合征(MDS)是一种造血干细胞和祖细胞(HSPC)的疾病 然而，在红细胞减少症中，这种功能失调的造血功能的遗传原因仍不清楚。差不多了 所有患者都患有贫血，这是发病率、死亡率和医疗费用的主要原因。删除部分或全部 7号染色体[-7/del(7q)]是MDS常见的细胞遗传学异常，预后不良。我们 发现CUX1，一个编码在7q上的含有同源结构域的转录因子，在 骨髓性疾病。我们报道了CUX1在人类和人类中都具有高度保守的调节功能 果蝇血细胞。CUX1失活突变自那以后在MDS中被报道，并独立于 与预后不良有关。我们现在已经生成了一个创新的CUX1击倒鼠标模型。 CUX1基因敲除的小鼠发展为一种自发性骨髓增殖性疾病，具有许多人类MDS的特征， 包括巨核细胞、粒细胞和红系发育不良，以及致命性贫血。初步研究 提示CUX1基因敲除影响多个阶段的造血，破坏早期HSPC功能，如 以及阻止红系发育的晚期。一个重大的知识鸿沟，这个提议就是这样设计的 要解决的是CUX1调节正常造血的机制。总体目标是 确定CUX1在正常HSPC和红系祖细胞中的转录作用及其途径 CUX1下游单倍体不足导致红系分化受阻。目标1：假设-CUX1是一种 HSPC的转录调节因子在小鼠和人类体内保守。我们将利用我们的 一种用于体内分析CUX1调节HSPC静止、增殖和... 差异化。我们将与原代人类HSPC进行互补研究，以建立 这部作品的翻译相关性。我们将利用前沿的功能基因组学方法来 鉴定人HSPC中的CUX1基因组靶点。目的2：假设--CUX1促进红细胞周期 通过抑制PI3K信号通路退出末端分化所必需的基因。我们将确定具体的 CUX1基因敲除对小鼠红细胞生成发育阶段的影响我们将确定 CUX1在人类红细胞发育中的保守作用，以及CUX1缺乏诱导的途径 扰乱了红细胞的生成。我们对原代人类造血干细胞的功能和基因组分析将与体内相吻合 旨在阐明正常红细胞生成中CUX1转录调控的关键作用。这项工作将 通过确定分子机制，对HSC和红系生物学领域产生积极影响 其中CUX1调节正常的HSC功能和疾病状态下CUX1缺乏的发病机制。我们的 研究将揭示治疗MDS患者贫血的新治疗靶点和MDS的小鼠模型 用于临床前研究。

PROJECT SUMMARY Myelodysplastic syndromes (MDS) are disorders of hematopoietic stem and progenitor cells (HSPCs) that results in cytopenias, however, the genetic causes of this dysfunctional hematopoiesis remain unclear. Almost all patients suffer anemia, a major cause of morbidity, mortality, and health care costs. Deletion of part or all of chromosome 7 [-7/del(7q)] is a common cytogenetic abnormality in MDS and carries a poor prognosis. We identified CUX1, a homeodomain-containing transcription factor encoded on 7q, to be frequently inactivated in myeloid diseases. We reported that CUX1 has highly conserved regulatory functions in both human and Drosophila blood cells. CUX1 inactivating mutations have since been reported in MDS and are independently associated with a poor prognosis. We have now generated an innovative Cux1 knockdown mouse model. Cux1-knockdown mice develop a spontaneous myeloproliferative disorder with many features of human MDS, including megakaryocyte, granulocyte, and erythroid dysplasia, and a fatal anemia. Preliminary studies indicate that Cux1 knockdown impacts multiple stages of hematopoiesis, disrupting early HSPC functions as well as blocking late stages of erythroid development. A major knowledge gap, which this proposal is designed to address, is the mechanism by which CUX1 regulates normal hematopoiesis. The overall objective is to determine the transcriptional role for CUX1 in normal HSPCs and erythroid progenitors and the pathways downstream of CUX1 haploinsufficiency that block erythroid differentiation. Aim 1: Hypothesis – CUX1 is a transcriptional regulator of HSPC homeostasis conserved in mice and humans. We will take advantage of our novel mouse model for in vivo analyses of Cux1 regulation of HSPC quiescence, proliferation, and differentiation. We will perform complementary studies with primary human HSPCs to establish the translational relevance of this work. We will capitalize on leading-edge functional genomics approaches to identify CUX1 genomic targets in human HSPCs. Aim 2: Hypothesis – CUX1 promotes erythroblast cell cycle exit necessary for terminal differentiation by repressing PI3K signaling. We will identify the specific developmental stage of erythropoiesis disrupted by Cux1 knockdown in mice. We will determine the conserved role for CUX1 in human red cell development, and the pathways induced by CUX1 deficiency that disrupt erythropoiesis. Our functional and genomic analyses of primary human HSCs will dovetail with in vivo assays to elucidate the critical role for CUX1 transcriptional regulation of normal erythropoiesis. This work will have a positive impact on the fields of HSC and erythroid biology by identifying the molecular mechanism by which CUX1 regulates normal HSC functions and the pathogenesis of CUX1-deficiency in disease states. Our studies will reveal novel therapeutic targets for treating anemia in MDS patients and a murine model of MDS for preclinical studies.