Role of autophagy in normal and transformed hematopoietic stem cells

自噬在正常和转化造血干细胞中的作用

• 批准号: 8671387
• 负责人: Emmanuelle Passegue
• 金额: $ 32.73万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-01 至 2019-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8671387
• 关键词: Address; Affect; Autophagocytosis; Biochemical; Biological Preservation; Biology; Blood; Blood Cells; Bone Marrow; Cell Maintenance; Cell Respiration; Cell physiology; Cells; Chemicals; Chronic Myeloid Leukemia; Chronic-Phase Myeloid Leukemia; Dependency; Development; Disease; Eating; Ensure; Food deprivation (experimental); Garbage; Gene Expression; Genes; Genetic; Genome Stability; Goals; Hematologic Neoplasms; Hematological Disease; Hematopoiesis; Hematopoietic stem cells; Homeostasis; Human; Hypoxia; Investigation; Leukemic Hematopoietic Stem Cell; Life; Lysosomes; Maintenance; Malignant - descriptor; Mediating; Metabolic; Metabolic stress; Molecular Chaperones; Molecular Target; Mus; Myelogenous; Myeloproliferative disease; Organelles; PI3K/AKT; Pathogenesis; Pathway interactions; Prevention; Process; Production; Proteins; Protocols documentation; Reactive Oxygen Species; Regulation; Resistance; Role; Signal Transduction; Staging; Stem Cell Development; Stem cells; Stress; System; Therapeutic; Tyrosine Kinase Inhibitor; Vesicle; Withdrawal; bcr-abl Fusion Proteins; biological adaptation to stress; cell transformation; coping; cytokine; granulocyte; in vivo; inhibitor/antagonist; insight; leukemia; macrophage; microbial; mouse model; novel; progenitor; programs; public health relevance; response; self-renewal; stem cell biology; stem cell therapy; therapy resistant; trafficking; transcription factor; ward

DESCRIPTION (provided by applicant): The overall goal of this application is to understand how autophagy supports the maintenance and function of blood-forming hematopoietic stem cells (HSC), and how corruption of this stress-response mechanism in transformed HSCs contributes to the development of myeloid malignancies such as chronic myelogenous leukemia (CML). We recently demonstrated that HSCs survive metabolic stress by inducing a robust protective autophagy response (Warr et al., 2013). In particular, we showed that the transcription factor FoxO3A is essential to maintain a pro-autophagy gene program that poises HSCs for rapid autophagy induction. However, how HSCs sense metabolic stress and activate autophagy is still unknown, and much remains to be understood about the role of autophagy in normal and transformed HSCs. We will use both pharmacological and genetic approaches to dissect the contribution of autophagy to HSC biology, and our established Scl- tTA:TRE-BCR/ABL (tTA-BA) mouse model of human chronic phase CML (Reynaud et al., 2011) to probe the function of autophagy in leukemia-initiating stem cell (LSC) activity and CML development. In Specific Aim 1, we will determine the mechanisms by which HSCs activate autophagy. We will use our established protocols to induce metabolic stress in HSCs ex vivo upon cytokine withdrawal and in vivo upon food deprivation, and will take advantage of existing genetic mouse models and chemical inhibitors to identify how HSCs sense metabolic stress and trigger autophagy induction. These approaches will establish how HSCs elicit a protective autophagy response upon metabolic challenges. In Specific Aim 2, we will address how loss of autophagy affects HSC function and genomic stability in vivo, and investigate whether alternative forms of protein and organelle turnover can support the long-term maintenance of autophagy-deficient HSCs. These approaches will delineate how autophagy is normally utilized by HSCs in vivo, and how its abrogation alters normal hematopoiesis. In Specific Aim 3, we will probe the function of autophagy in transformed BCR/ABL- expressing HSCs, and will take advantage of our inducible tTA-BA mouse model to investigate the contribution of autophagy to CML pathogenesis and response of CML LSCs to tyrosine kinase inhibitor (TKI) treatments. These approaches will provide important new insights into the mechanisms of malignant transformation in the blood system. They will elucidate the contribution of autophagy in HSC transformation and CML development, and determine how the autophagy machinery can be manipulated to achieve a therapeutic benefit. Taken together, these studies will uncover how corruption of an essential mechanism of cell preservation normally used by HSCs to maintain blood homeostasis contributes to the aberrant function of transformed HSCs and the development of blood diseases.

描述（由申请人提供）：本申请的总体目标是了解自噬如何支持造血造血干细胞（HSC）的维持和功能，以及转化的HSC中这种应激反应机制的破坏如何导致慢性粒细胞白血病（CML）等骨髓恶性肿瘤的发展。我们最近证明，HSC 通过诱导强大的保护性自噬反应来抵抗代谢应激（Warr 等，2013）。特别是，我们发现转录因子 FoxO3A 对于维持促自噬基因程序至关重要，该程序使 HSC 能够快速诱导自噬。然而，HSC 如何感知代谢应激并激活自噬仍不清楚，并且自噬在正常和转化的 HSC 中的作用仍有待了解。我们将使用药理学和遗传学方法来剖析自噬对 HSC 生物学的贡献，并建立人类慢性期 CML 的 Scl-tTA:TRE-BCR/ABL (tTA-BA) 小鼠模型 (Reynaud et al., 2011)，以探讨自噬在白血病起始干细胞 (LSC) 活性和 CML 发展中的功能。在具体目标 1 中，我们将确定 HSC 激活自噬的机制。我们将使用我们既定的方案，在细胞因子撤除后和体内食物剥夺时在体外诱导 HSC 代谢应激，并将利用现有的遗传小鼠模型和化学抑制剂来确定 HSC 如何感知代谢应激并触发自噬诱导。这些方法将确定 HSC 如何在代谢挑战时引发保护性自噬反应。在具体目标 2 中，我们将讨论自噬的丧失如何影响 HSC 功能和体内基因组稳定性，并研究蛋白质和细胞器更新的替代形式是否可以支持自噬缺陷的 HSC 的长期维持。这些方法将描述 HSC 在体内通常如何利用自噬，以及其废除如何改变正常造血功能。在具体目标 3 中，我们将探讨表达 BCR/ABL 的转化 HSC 中自噬的功能，并将利用我们的诱导型 tTA-BA 小鼠模型来研究自噬对 CML 发病机制的贡献以及 CML LSC 对酪氨酸激酶抑制剂 (TKI) 治疗的反应。这些方法将为血液系统恶性转化机制提供重要的新见解。他们将阐明自噬在 HSC 转化和 CML 发展中的贡献，并确定如何操纵自噬机制以实现治疗效果。总而言之，这些研究将揭示造血干细胞通常用于维持血液稳态的细胞保存基本机制的损坏如何导致转化造血干细胞的功能异常和血液疾病的发展。