Mechanisms of Hematopoietic Stem Cell Maintenance

造血干细胞维持机制

基本信息

批准号：
8513404
负责人：
Emmanuelle Passegue
金额：
$ 36.77万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-08-01 至 2016-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8513404
关键词：
Address Apoptosis Apoptotic Biological Biological Preservation Biology Blood Blood Cells Bone Marrow Caspase Cell Cycle Cell Maintenance Cell Respiration Cell division Cell physiology Cells Cellular Stress Cessation of life Chronic stress Development Ensure Equilibrium Family member G0 Phase Genes Genetic Genomics Genotoxic Stress Goals Hematologic Neoplasms Hematological Disease Hematopoietic Hematopoietic System Hematopoietic stem cells Homeostasis Human Hypoxia Imagery In Situ Investigation Ionizing radiation Life Ligands Maintenance Mediating Metabolic Mitochondria Molecular Molecular Profiling Molecular Target Mus Myelogenous Myeloid Cells Myeloid Leukemia Myeloproliferative disease Oncogenic Outcome Pathway interactions Population Production Property Proteins Receptor Activation Recruitment Activity Regulation Resistance Role Signal Transduction Stem cells Stimulus Stress System TNFRSF5 gene Testing acute stress alpha helix bcr-abl Fusion Proteins biological adaptation to stress cell injury functional outcomes granulocyte in vivo insight killings leukemia leukemogenesis macrophage mouse model prevent progenitor receptor research study response small hairpin RNA stem stem cell population therapy resistant

项目摘要

DESCRIPTION (provided by applicant): The overall goal of this application is to uncover how apoptosis is used by hematopoietic stem cells (HSC) to preserve themselves and produce myeloid cells, and to address how corruption of apoptosis regulation contributes to the development of myeloid malignancies. While a wealth of information is currently available on the mechanistic role of particular components of the apoptotic machinery, we still lack a comprehensive understanding of how apoptosis regulates the biological activity of early stem and progenitor cells. Furthermore, we still do not fully understand how corruption of apoptosis regulation endows transformed HSCs with aberrant survival properties and resistance to therapy. Here, we will use an array of complementary approaches to dissect the regulation and implication of the intrinsic mitochondrial and extrinsic death receptor (DR) pathways of apoptosis in HSC function under normal and diseased conditions. Studies in Specific Aim 1 will focus on understanding the role of the intrinsic mitochondrial pathway of apoptosis. We will extend our investigations of hematopoietic-specific BakBaxcKO mice to delineate the precise contribution of this death mechanism to blood homeostasis in vivo. We will also directly test how the ratio of Bcl2 proteins controls the balance between survival and elimination in HSCs and granulocyte/macrophage progenitors (GMP). We will perform an in vivo shRNA screen to understand the role of the pro-apoptotic Bcl2 genes and will use stabilized alpha helices of Bcl2 domains (SAHB) to probe the functional implication of the pro-survival family members. These experiments will yield a detailed molecular and cellular understanding of how apoptotic signals mediated through the intrinsic mitochondrial pathway contribute to the maintenance of a functional HSC compartment and regulate myeloid cell production. In Specific Aim 2, we will address the role of the extrinsic DR pathway of apoptosis. We will use our new in situ visualization approach to investigate how local expression of DR ligands in the BM cavity can activate the DR pathway in HSCs and GMPs. We will also use a combination of molecular profiling, ex vivo analyses and in vivo experiments in complementary genetic mouse models (i.e., Faslpr/lpr, hematopoietic-specific Caspase-8cKO, p50-/- mice) to dissect the regulation and functional outcome of DR activation in HSCs and GMPs. These experiments will provide a unique understanding of how the extrinsic DR pathway contributes to HSC maintenance and regulates myeloid cell production, either by itself or in cooperation with the intrinsic mitochondrial pathway. Studies in Specific Aim 3 will address how corruption of apoptosis regulation endows transformed HSCs with aberrant survival properties and contributes to the development of myeloproliferative neoplasms (MPN). We will use our established mouse models of human MPNs (i.e., junB-deficient and inducible tTA-BCR/ABL mice) to identify changes that occur in the regulation of the apoptotic machinery in transformed HSCs and GMPs, and to understand the functional implications of these deregulations in providing aberrant survival properties to these populations. We will also assess whether targeting these aberrant features of apoptosis regulation can be used to specifically kill transformed HSCs with leukemia-initiating stem cell (LSC) properties. These experiments will uncover how corruption of a mechanism of cell preservation normally used by HSCs to maintain blood homeostasis contributes to the aberrant function of transformed HSCs and the development of myeloid malignancies.

描述（由申请人提供）：本申请的总体目标是揭示造血干细胞（HSC）如何使用细胞凋亡来保存自己并产生髓样细胞，并解决细胞凋亡调节的腐败如何影响髓样恶性肿瘤的发展。尽管目前有大量有关凋亡机制特定成分的机械作用的信息，但我们仍然对凋亡如何调节早期茎和祖细胞的生物学活性缺乏全面的了解。此外，我们仍然不完全了解凋亡调节的腐败如何转化HSC具有异常的生存特性和对治疗的抵抗力。在这里，我们将使用一系列互补方法来剖析HSC功能在正常和患病条件下凋亡在HSC功能中的内在线粒体和外在死亡受体（DR）途径的调节和含义。特定目标1中的研究将集中于了解凋亡的内在线粒体途径的作用。我们将扩展对造血特异性bakbaxcko小鼠的研究，以描绘这种死亡机制对体内血液稳态的确切贡献。我们还将直接测试Bcl2蛋白的比率如何控制HSC和粒细胞/巨噬细胞祖细胞（GMP）中生存与消除之间的平衡。我们将执行一个体内shRNA筛选，以了解促凋亡BCL2基因的作用，并将使用Bcl2域（SAHB）的稳定α螺旋来探测亲寿命家庭成员的功能含义。这些实验将产生详细的分子和细胞理解，了解通过固有线粒体途径介导的凋亡信号如何有助于维持功能性HSC室并调节髓样细胞的产生。在特定的目标2中，我们将解决凋亡的外在DR途径的作用。我们将使用新的原位可视化方法来研究BM腔中配体的局部表达如何激活HSC和GMP中的DR途径。我们还将在互补的遗传小鼠模型（即FASLPR/LPR，造血特异性caspase-8cko，p50-/ - 小鼠）中使用分子分析，离体分析和体内实验的组合来解剖调节和功能。 HSC和GMP中的DR激活。这些实验将对外在DR途径如何促进HSC维持并调节髓样细胞的产生，或与内在的线粒体途径合作，并提供独特的理解。特定目标3中的研究将解决细胞凋亡调节的腐败如何转化HSC具有异常的生存特性，并有助于骨髓增生性肿瘤（MPN）的发展。我们将使用既定的人类MPN的鼠标模型（即JUNB缺乏和诱导的TTA-BCR/ABL小鼠）来识别在转化的HSC和GMPS中凋亡机械调节中发生的变化，并了解理解这些放松调节为这些人群提供异常的生存特性。我们还将评估针对这些异常调节的异常特征是否可用于特异性杀死具有白血病发射干细胞（LSC）特性的转化的HSC。这些实验将发现HSC通常用于维持血液稳态的细胞保存机制的腐败如何有助于转化的HSC的异常功能和髓样恶性肿瘤的发展。