Effects of ageing and DNA damage on activity and clonality of the hematopoietic stem cell pool

衰老和 DNA 损伤对造血干细胞库活性和克隆性的影响

• 批准号: 401355815
• 负责人: Dr. Alexander Gerbaulet
• 金额: --
• 依托单位: Institut für Immunologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/401355815?language=en
• 关键词: Effects; ageing; DNA; damage; activity

The hematopoietic system replenishes vast numbers of mature blood cells each day and can adapt rapidly to situations of even higher demand for mature blood cells e.g. infection or blood loss. While this enormous regenerative capacity is maintained over the entire life span, specific alterations of the system occur at old age that likely are associated with accumulating genome damage. How quiescent subpopulations of hematopoietic stem cells (HSCs) participate in steady state and stress hematopoiesis at young and old age is only partially understood until today. We will address why the hematopoietic systems maintains a substantial number of these quiescent HSCs which hardly contribute to steady state blood cell production. We hypothesize that quiescent HSCs are needed as a functional reserve to prevent exhaustion of the hematopoietic system, to maintain a polyclonal stem cell pool and to counteract accumulation of DNA damage at older age. Our project first aims to track the fate of a quiescent HSC subset within the intact bone marrow under steady state and stress conditions. Mathematical modeling of the experimental data will address how quiescent and proliferative subpopulations of hematopoietic stem and progenitor cells are hierarchically related to each other. In parallel, we will generate new mouse models for in situ (i.e. within the physiological environment without transplantation or ex vivo manipulation) clonal tagging and tracking of the hematopoietic system by the means of CRISPR/Cas9 genome editing. We will then investigate the clonality of stem and progenitor populations and the contribution of single hematopoietic cells in steady-state, upon ageing and after chronic exposure to DNA damaging hazards. As the ageing hematopoietic system frequently shows expansion of discrete hematopoietic clones and progression to pre-leukemic conditions, including myelodysplastic syndrome, we will investigate the effects of oncogenic driver mutations on the clonality of hematopoiesis and the activity and differentiation of stem cell and precursor clones.

造血系统每天补充大量的成熟血细胞，并能迅速适应对成熟血细胞的更高要求的情况，例如感染或失血。虽然这种巨大的再生能力在整个生命周期中都保持着，但该系统在老年时会发生特定的变化，这可能与累积的基因组损伤有关。静止的造血干细胞(HSCs)亚群如何在年轻和老年参与稳定状态和应激造血直到今天才被部分了解。我们将解决为什么造血系统维持大量的这些静止的HSCs，这些细胞几乎不会对稳定状态的血细胞产生做出贡献。我们假设静止的HSCs是需要的功能储备，以防止造血系统耗尽，维持多克隆干细胞库，并在老年时抵消DNA损伤的积累。我们的项目首先旨在追踪在稳定状态和压力条件下完整骨髓中静止的HSC亚群的命运。对实验数据的数学建模将解决造血干细胞和祖细胞的静止和增殖亚群是如何相互层级联系的。同时，我们将通过CRISPR/Cas9基因组编辑的方法，建立新的小鼠模型，用于原位(即在没有移植或体外操作的生理环境中)克隆标记和追踪造血系统。然后，我们将调查干细胞和祖细胞群体的克隆性，以及单个造血细胞在稳定状态、老化和长期暴露于DNA损伤危险后的贡献。由于老化的造血系统经常表现为离散的造血克隆的扩张和进展到白血病前状态，包括骨髓增生异常综合征，我们将研究致癌驱动基因突变对造血克隆以及干细胞和前体克隆的活性和分化的影响。