Identification and targeting of pathways separating healthy stem cell aging from malignant transformation

鉴定和靶向区分健康干细胞衰老与恶性转化的途径

• 批准号: 10461093
• 负责人: Britta Will
• 金额: $ 38.2万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10461093
• 关键词: Acute Myelocytic Leukemia; Adult; Age; Aging; Autophagocytosis; Biosensor; Blood; Blood Cells; Cell Compartmentation; Cell physiology; Cells; Chemicals; Chronic stress; Clinical; Cytoplasmic Organelle; Cytoplasmic Protein; DNA Damage; Data; Defect; Development; Disease; Dysmyelopoietic Syndromes; Eating; Elderly; Evolution; Functional disorder; Genetic; Hematologic Neoplasms; Hematological Disease; Hematopoiesis; Hematopoietic Neoplasms; Hematopoietic System; Hematopoietic stem cells; Human; Human Cell Line; Impairment; Intracellular Accumulation of Lipids; Knowledge; Link; Lysosomes; Malignant - descriptor; Malignant Neoplasms; Mediating; Membrane Proteins; Modeling; Molecular; Molecular Chaperones; Mus; Myeloproliferative disease; Non-Malignant; Pathology; Pathway interactions; Patients; Pattern; Phase; Phenotype; Physiological; Premature aging syndrome; Process; Protein Isoforms; Proteins; RNA Splicing; Reactive Oxygen Species; Recycling; Reporter; Resolution; Role; System; Testing; Therapeutic; Tissues; Variant; adult stem cell; aged; base; cancer stem cell; cell type; curative treatments; healthy aging; inhibition of autophagy; inhibitor; insight; leukemogenesis; lipid metabolism; mouse model; novel therapeutic intervention; novel therapeutics; premalignant; prospective; self-renewal; small molecule; stem cell aging; stem cell function; stem cells; tool; wasting

ABSTRACT Myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) are generally incurable hematologic malignancies, originating from aberrant hematopoietic stem cells (HSCs). These diseases occur mainly in the elderly and are preceded by an often-unrecognized precancerous phase, which can last for years and is hallmarked by a progressively changing HSC compartment. Such molecularly and functionally diverging stem cells, termed pre-leukemic stem cells (pre-LSCs), harbor a higher propensity to undergo malignant transformation. Mechanisms that separate the healthy aging process from cancer evolution are incompletely resolved. This gap in our knowledge poses a significant challenge for the development of curative therapies for myeloid malignancies for which cure rates have mostly remained below 30% over the last decades. Our study will investigate the role of chaperone-mediated autophagy (CMA), a highly selective subtype of autophagy, which has not been systematically characterized in the hematopoietic system thus far. Contrary to macroautophagy, CMA specifically degrades proteins containing defined recognition motifs (“KFERQ”, and variants), and maintains integrity and proper function of many cell types during chronic stress and aging. CMA declines in and critically contributes to several age-associated pathologies, yet its role in leukemogenesis and cancer stem cell evolution is unknown. Using new genetic mouse models, we have obtained exciting preliminary data demonstrating that CMA sustains the function of healthy HSCs. Furthermore, we found that impairment of CMA increased pre-LSC function that appears to be linked with increased levels of reactive oxygen species, accumulating in CMA-deficient stem cells. For this study, we hypothesize that CMA protects against stem cell dysfunction and malignant transformation. We will utilize a complementary model set consisting of genetic mouse models, human cell lines and primary patient-derived cells for the study of (1) CMA activation patterns in healthy HSCs and pre-LSCs (leveraging a CMA reporter mouse and lentiviral CMA biosensors for primary human cells), (2) molecular and (3) functional consequences of CMA inactivation and stimulation. We will also test a new chemical CMA activator tool compound for its efficacy to promote healthy HSCs and impair pre-LSCs, which could be further developed for clinical use. Our study will provide new insights into a molecular mechanism declining during aging and predisposing adult tissue-specific stem cells to malignant transformation, which will have important implications for the development of new therapeutic strategies for targeting autophagy in myeloid malignancies, and possibly other stem cell-derived cancers.

摘要 骨髓增生异常综合征（MDS）和急性髓性白血病（AML）通常是不可治愈的血液系统疾病。 来源于异常造血干细胞（HSC）的恶性肿瘤。这些疾病主要发生在 老年人和之前的一个经常被忽视的癌前阶段，这可能会持续多年，是标志性的 逐渐变化的HSC隔室。这种分子和功能上不同的干细胞，被称为 前白血病干细胞（pre-LSC）具有更高的经历恶性转化的倾向。 将健康衰老过程与癌症演变分开的机制尚未完全解决。这一差距 在我们的知识构成了一个重大的挑战，为发展的治愈性治疗骨髓恶性肿瘤 在过去的几十年里，治愈率大多保持在30%以下。 我们的研究将探讨分子伴侣介导的自噬（CMA）的作用，CMA是一种高度选择性的自噬亚型， 自噬，迄今尚未在造血系统中系统地表征。违反 在巨自噬中，CMA特异性降解含有确定的识别基序的蛋白质（“KFERQ”，和 变异），并在慢性应激和衰老过程中保持许多细胞类型的完整性和正常功能。CMA 在几种与年龄相关的病理学中的下降和关键性贡献，但其在白血病发生和 癌症干细胞的进化是未知的。使用新的遗传小鼠模型，我们已经获得了令人兴奋的初步结果。 数据表明CMA维持健康HSC的功能。此外，我们发现， CMA增加了前LSC功能，这似乎与活性氧水平的增加有关， 在缺乏CMA的干细胞中积累。在这项研究中，我们假设CMA可以防止干细胞 功能障碍和恶性转化。 我们将利用由遗传小鼠模型、人类细胞系和原代细胞组成的互补模型集。 患者来源的细胞用于研究（1）健康HSC和前LSC中的CMA激活模式（利用 用于原代人细胞的CMA报告小鼠和慢病毒CMA生物传感器），（2）分子和（3）功能 CMA失活和刺激的后果。我们还将测试一种新的化学CMA激活剂工具 化合物促进健康HSC和损害前LSC的功效，其可以进一步开发用于 临床应用。 我们的研究将提供新的见解，在衰老过程中下降的分子机制和易感成人 组织特异性干细胞的恶性转化，这将有重要意义的 开发针对骨髓恶性肿瘤中自噬的新治疗策略， 干细胞衍生的癌症。