Defining the Pathogenesis of Del(7q) in Hematopoietic Stem Cells

定义造血干细胞中 Del(7q) 的发病机制

• 批准号: 10387288
• 负责人: Matthew Jotte
• 金额: $ 5.18万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10387288
• 关键词: Acute leukemia; Adult; Anemia; Apoptosis; Automobile Driving; Bioinformatics; Blood; CD34 gene; CRISPR/Cas technology; Cell Proliferation; Cells; Childhood; Chromatin; Chromosome 7; Chromosome abnormality; Clonal Expansion; Cytogenetics; Data; Development; Diploidy; Disease; Dose; Doxycycline; Dysmyelopoietic Syndromes; Dysplasia; EZH2 gene; Electroporation; Engineering; Environment; Epigenetic Process; Erythropoiesis; Etiology; Gene Deletion; Gene Dosage; Genes; Genetic; Genetic Transcription; Genomics; Hematopoiesis; Hematopoietic stem cells; Histones; Homeobox; Human; In Vitro; Ineffective Hematopoiesis; K-562; K562 Cells; Karyotype; Knock-out; Knowledge; Lead; Leukemic Cell; Maintenance; Malignant Neoplasms; Methodology; Methyltransferase; Modeling; Molecular; Molecular Abnormality; Monosomy 7; Mus; Mutation; Myelogenous; Myeloid Cells; Myelopoiesis; Myeloproliferative disease; Neoplasms; Onset of illness; Outcome; Pathogenesis; Pathogenicity; Peripheral; Physicians; Population; Prognosis; Recurrence; Research Personnel; Risk; Role; Scientist; Series; Syndrome; Synteny; Technical Expertise; Techniques; Training; Transcription Alteration; Transplantation; Treatment Efficacy; Tumor Suppressor Genes; Work; animal model development; base; career; cell growth; chromosome 7 loss; chromosome 7q loss; combinatorial; cytopenia; dosage; druggable target; experimental study; high risk; in vivo; knock-down; knockout gene; mouse model; new therapeutic target; novel therapeutics; nuclease; skills; small hairpin RNA; stemness; transcription factor; transcriptome sequencing

PROJECT SUMMARY/ABSTRACT Deletions of all or part of chromosome 7 [-7/del(7q)] are among the most common karyotypic abnormalities in myeloid diseases, particularly high-risk myeloid diseases. Myelodysplastic syndrome (MDS) is a series of clonal disorders characterized by ineffective hematopoiesis, leading to peripheral cytopenias and dysplasia in one or more blood lineages with risk of transformation to acute leukemia. -7/del(7q) is found in 10% of adult MDS cases and, strikingly, in up to 50% of pediatric MDS cases. The presence of -7/del(7q) is associated with a poor karyotype and higher risk MDS, and carries a worse prognosis than cases with diploid chromosome 7. -7/del(7q) is often the only cytogenetic finding, and in a subset of pediatric MDS cases is the sole detectable molecular abnormality, strongly suggesting a driving role for chromosome 7 deletions in disease pathogenesis. There have been no new therapies for MDS in over a decade, highlighting an urgent need to better understand the recurrent genetic features of MDS that may lead to new treatment options. The lack of synteny between human and mouse chromosome 7 is a major barrier in the development of animal models of -7/del(7q). In a breakthrough in the field, our lab identified CUX1, a homeobox transcription factor shown to regulate cell proliferation and apoptosis, as a haploinsufficient myeloid tumor suppressor gene located in a commonly deleted region of 7q. Our lab engineered a doxycycline-inducible shRNA CUX1- knockdown mouse, and mice deficient in Cux1 develop a myeloid disease with trilineage dysplasia and lethal anemia, hallmarks of MDS. These data strongly support a role for this 7q-encoded gene in MDS etiology. However, chromosome 7 deletions are often large and span additional genes that alter hematopoiesis or lead to myeloid disease when deleted in mouse models. These data suggest 7q may be a contiguous gene syndrome region, in which loss of multiple neighboring genes en bloc contributes to disease development. Our preliminary data show CUX1 loss in human K562 leukemia cells decreases the repressive epigenetic histone mark H3K27me3. We further show that combined loss of Cux1 and the 7q gene Ezh2, an H3K27 methyltransferase, in murine hematopoietic progenitors synergistically increases myeloid cell expansion in vitro, compared to either gene alone. These data provide support for the hypothesis that 7q is a contiguous gene syndrome region. This proposal aims to: 1) leverage CRISPR-Cas9 gene editing to identify combinatorial 7q gene deletions that cooperate with Cux1 loss to drive del(7q) pathogenesis; and 2) define mechanisms by which loss of 7q genes drives del(7q) pathogenesis by characterizing the epigenetic and transcriptional landscape of cells deficient in Cux1 alone or with combined Ezh2 loss. This proposal will advance our understanding of chromosome 7 deletions and provide me with a specialized skill set in myeloid neoplasia and genomics that will propel me toward a career as an independent investigator.

项目摘要/摘要 7号染色体全部或部分缺失[-7/del(7q)]是最常见的核型之一 髓系疾病的异常，特别是高风险的髓系疾病。骨髓增生异常综合征(MDS)是 一系列以无效造血为特征的克隆性疾病，导致外周血细胞减少和 一个或多个血统中的发育不良，有转化为急性白血病的风险。-7/del(7q)占10% 在成人MDS病例中，尤其是在高达50%的儿童MDS病例中。-7/del(7q)的存在与 核型较差，MDS风险较高，与二倍体染色体患者相比预后更差 7.-7/del(7q)通常是唯一的细胞遗传学发现，在儿童MDS病例的子集中是唯一可检测到的。 分子异常，强烈提示7号染色体缺失在疾病发病机制中的驱动作用。 十多年来，MDS一直没有新的治疗方法，突显出迫切需要更好地了解 MDS的复发遗传特征可能导致新的治疗选择。 人类和小鼠7号染色体之间缺乏同步性是发展的一个主要障碍。 动物模型-7/del(7q)。在该领域的一项突破中，我们的实验室发现了CUX1，一种同源框转录 调节细胞增殖和凋亡的因子，作为单倍体不足的髓系肿瘤抑制基因 位于7q的常见缺失区域。我们的实验室设计了一种多西环素诱导的shRNA CUX1- 基因敲除的小鼠和CUX1基因缺陷的小鼠发展为一种伴有三联体发育不良和致死性的髓系疾病 贫血，MDS的特征。这些数据有力地支持了这个7q编码基因在MDS病因学中的作用。 然而，7号染色体的缺失通常很大，并且跨越了改变造血或导致 在小鼠模型中，当被删除时，髓系疾病。这些数据表明，7q可能是一种邻接基因综合征。 区域，在该区域中，多个相邻基因的整体丢失有助于疾病的发展。我们的预赛 数据显示，人K562白血病细胞中CUX1的缺失降低了抑制性表观遗传组蛋白标记 H3K27me3。我们进一步证明，CUX1和7q基因Ezh2，一种H3K27甲基转移酶， 在小鼠中，造血祖细胞在体外协同促进髓系细胞的增殖 只有吉恩一个人。这些数据支持7q是一个相邻的基因综合征区域的假设。这 建议旨在：1)利用CRISPR-Cas9基因编辑来识别组合7q基因缺失， 与CUX1缺失协同驱动del(7q)发病；2)确定7q基因缺失的机制 通过表征缺乏基因的细胞的表观遗传和转录图景来驱动del(7q)的发病 CUX1单独或合并Ezh2丢失。这一建议将增进我们对7号染色体的理解。 并为我提供了一套髓系肿瘤和基因组学方面的专业技能，这将推动我 成为一名独立调查员。