Functional Genomic Dissection of Refractory Anemia

难治性贫血的功能基因组解析

基本信息

批准号：
8486470
负责人：
Benjamin Levine Ebert
金额：
$ 39.1万
依托单位：
BRIGHAM AND WOMEN'S HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-09-15 至 2015-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8486470
关键词：
5q31 5q32 Acute leukemia Address Alleles Anemia Animal Model Apoptosis Applications Grants Binding Biogenesis Biological Biological Assay Biology Blood Bone Marrow CD34 gene Candidate Disease Gene Cell Cycle Arrest Cell physiology Cells Characteristics Childhood Chromosome Arm Chromosome Deletion Chromosomes Chromosomes, Human, Pair 5 Code Congenital Disorders Defect Development Diamond-Blackfan anemia Disadvantaged Disease Dissection Dysmyelopoietic Syndromes Epigenetic Process Erythroid Erythroid Progenitor Cells Erythropoiesis Failure Funding Gene Expression Profiling Gene Targeting Genes Genetic Genetic Engineering Genetic Translation Hematopoiesis Hematopoietic Hematopoietic stem cells Human In Vitro Individual Ineffective Hematopoiesis Lead Lesion Link MDM2 gene Macrocytic Anemia Malignant Neoplasms Megakaryocytes Messenger RNA Methodology MicroRNAs Micromegakaryocyte Modeling Molecular Molecular Abnormality Mus Oncogenes Pancytopenia Pathogenesis Pathway interactions Patients Peripheral Phenotype Polyribosomes Process Production Proteins Protocols documentation RNA RNA Interference RPS19 gene Reading Refractory anemias Regulation Relative (related person)Ribosomal Proteins Ribosomes Role Stem cells Study models Sucrose Syndrome System Technology Testing Time Translating Translations Tumor Suppressor Proteins Undifferentiated United States Validation Zebrafish base chromosome 5q loss chromosome 7q loss clinical phenotype functional genomics genetic manipulation in vivo insight interstitial leukemia novel novel therapeutics prevent protein activation public health relevance rRNA Precursor research study screening stem thrombocytosis

项目摘要

DESCRIPTION (provided by applicant): Myelodysplastic syndrome (MDS) is characterized by ineffective hematopoiesis, most commonly of the erythroid lineage, resulting in a phenotype termed refractory anemia. In the 5q- syndrome, a subtype of MDS, a single genetic lesion, a heterozygous, interstitial deletion of Chromosome 5q, causes a highly reproducible clinical phenotype, though the molecular basis of this phenotype was previously unknown. In the previous funding period, we identified one protein-coding gene, RPS14, and one miRNA, miR-145, that contribute to abnormal hematopoiesis in the 5q- syndrome. The finding that RPS14 haploinsufficiency causes a block in erythropoiesis, the dominant phenotype of the 5q- syndrome, established a previously unrecognized link between the 5q- syndrome and Diamond Blackfan Anemia, a congenital disorder with a similar phenotype that is also caused by genetic inactivation of one allele of genes encoding ribosomal proteins. We found that haploinsufficiency for miR-145 causes increased expression of a key target gene, FLI-1, leading to increased megakaryocyte production and the characteristic hypolobated micromegakaryocytes found in this syndrome. In this renewal application, we aim to understand the molecular basis for the effects of RPS14 haploinsufficiency and combined haploinsufficiency for RPS14 and miR-145, and to examine the effects of these lesions on hematopoietic stem cells. In addition, having established an approach to the identification of key MDS genes within chromosomal deletions, we will apply our methodology to identify a key gene within the 7q deletion, another common genetic lesion in MDS. In Aim 1, we will investigate the mechanism whereby ribosomal haploinsufficiency leads to impaired erythropoiesis. Current evidence supports two non-exclusive hypotheses. The first possibility is that selective activation of p53 in the erythroid lineage causes cell cycle arrest and apoptosis, resulting in macrocytic anemia. Alternatively, or additionally, abnormal ribosome biogenesis could lead to dysregulated mRNA translation and altered production of specific proteins. We will examine both hypotheses in primary human bone marrow progenitor cells. In Aim 2, we will examine hematopoiesis in genetically engineered murine models with conditional haploinsufficiency of RPS14, miR-145, or the combination of RPS14 and miR-145. In particular, we will use these models to examine the effect of each lesion on hematopoietic stem cell function. In Aim 3, we will extend our RNA interference screening approach to identify additional genes that are critical for the pathogenesis of MDS. Having demonstrated the ability to use this approach to identify haploinsufficiency disease genes on Chromosome 5q, we will next focus this technology towards the identification of novel MDS genes on Chromosome 7q. In aggregate, these experiments will provide critical insight into the molecular basis of myelodysplastic syndrome.

描述（由申请人提供）：骨髓增生异常综合征（MDS）的特征是无效造血，最常见的是红系血统，导致称为难治性贫血的表型。在 5q 综合征（MDS 的一种亚型）中，单一遗传病变、5q 染色体杂合、间质缺失会导致高度可重复的临床表型，尽管这种表型的分子基础以前未知。在之前的资助期间，我们发现了一种蛋白质编码基因 RPS14 和一种 miRNA miR-145，它们会导致 5q 综合征中的异常造血。 RPS14 单倍体不足会导致红细胞生成受阻，而红细胞生成是 5q 综合征的主要表型，这一发现建立了 5q 综合征与 Diamond Blackfan 贫血之间以前未被认识到的联系，Diamond Blackfan 贫血是一种具有相似表型的先天性疾病，也是由 5q 综合征的基因失活引起的。编码核糖体蛋白的基因的一种等位基因。我们发现 miR-145 的单倍体不足会导致关键靶基因 FLI-1 的表达增加，从而导致巨核细胞产量增加以及该综合征中发现的特征性低分叶微巨核细胞。在此更新应用中，我们的目标是了解 RPS14 单倍体不足以及 RPS14 和 miR-145 的组合单倍体不足影响的分子基础，并检查这些病变对造血干细胞的影响。此外，在建立了一种鉴定染色体缺失中关键 MDS 基因的方法后，我们将应用我们的方法来鉴定 7q 缺失（MDS 中另一种常见遗传病变）中的关键基因。在目标 1 中，我们将研究核糖体单倍体不足导致红细胞生成受损的机制。目前的证据支持两个非排他性假设。第一种可能性是红系谱系中 p53 的选择性激活导致细胞周期停滞和细胞凋亡，导致大细胞性贫血。或者或另外，异常的核糖体生物发生可能导致 mRNA 翻译失调和特定蛋白质的产生改变。我们将在原代人骨髓祖细胞中检验这两种假设。在目标 2 中，我们将检查 RPS14、miR-145 或 RPS14 和 miR-145 组合的条件单倍体不足的基因工程小鼠模型中的造血作用。特别是，我们将使用这些模型来检查每种病变对造血干细胞功能的影响。在目标 3 中，我们将扩展 RNA 干扰筛选方法，以确定对 MDS 发病机制至关重要的其他基因。在证明了使用这种方法识别 5q 染色体上的单倍体不足疾病基因的能力后，我们下一步将将该技术重点用于识别 7q 染色体上的新型 MDS 基因。总的来说，这些实验将为骨髓增生异常综合征的分子基础提供重要的见解。