Tracking dynamic interactions between haematopoietic stem cells and osteoblasts: molecular regulation of stem cell position and fate

追踪造血干细胞和成骨细胞之间的动态相互作用：干细胞位置和命运的分子调控

• 批准号: BB/I004033/1
• 负责人: Cristina Lo Celso
• 金额: $ 53.87万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FI004033%2F1
• 关键词: Tracking; dynamic; interactions; between; haematopoietic

Most blood cells are short lived and are constantly replaced by the balanced production of new progeny arising from blood stem cells through several commitment and differentiation steps. Blood cells are known to be quiescent and proliferate infrequently relative to their progeny. When they do so, they give rise to more stem cells (self-renewal) or to differentiating progeny. Blood stem cells finely tune the balance between quiescence, self-renewal and differentiation by sensing tissue damage and adjusting progeny generation to physiological and stress-induced demand. In the same way that a comfortable home contributes to family's happiness and the work environment influences employees' performance, correct positioning of blood stem cells in specific niches within the bone marrow space is crucial to ensure their proper functioning. Several studies indicate that bone-making cells, called osteoblasts, have an important role in regulating blood stem cell numbers and function; however, the few studies aimed at pinpointing blood stem cell location within the bone marrow have reported a wide range of positions and even when most observed cells are in the vicinity of osteoblasts only few are clearly in direct contact. As a number of stem cell niches observed in invertebrate model organisms or in different mammalian tissues function through direct interaction between the stem and niche cells, a controversy has arisen whether osteoblasts truly are the main component of the blood stem cell niche, provided such a niche exists at all. I have recently developed an in vivo imaging methodology that allows me to visualise transplanted blood stem cells within the bone marrow space immediately after their injection into the blood, and I can 'watch' the behaviour of the same cells until few days later. I have collected evidence that switching on or off certain molecular signals within transplanted blood stem cells can modulate their function by means of affecting their positioning. The current proposal seeks to apply and further develop in vivo imaging of blood stem cells in order to gain a definite answer on the existence, location and function of the blood stem cell niche. We will use as our working model transgenic mice expressing over-physiological levels of the Wnt inhibitor Dkk1 in all their osteoblasts, which have been shown to have decreased blood stem cell function and specifically self-renewal ability. We know that transplanted blood stem cells localize abnormally in Dkk bone marrow, and we plan to test whether this altered positioning is the cause of their malfunction. We will perform detailed time-lapse tracking of transplanted stem cells to ask whether cells closer to osteoblasts are more quiescent (less likely to divide) compared to those further away, and we will take advantage of novel photoconversion techniques to tag stem cells and their progeny residing in different locations and subsequently compare their function. Moreover, as current in vivo imaging technologies do not allow sub-cellular resolution, we will investigate whether co-culture of blood stem cells and osteoblasts from normal or Dkk mice can be used as a surrogate system to study in greater detail at least some of the events observed in the mice, and we will use them to closely track blood stem cells behaviour and morphology under normal and disadvantageous conditions. We will perform genome wide expression analysis of stroma and stem cells from self-renewal permissive or repressive cultures or mice, and we will focus on genes known to regulate cell-cell and cell-environment interactions. As a result, we will gain a comprehensive picture of the relationship between osteoblasts and blood stem cells, we will investigate whether stem cell position directly affects function, and we will learn what molecules are involved in the process.

大多数血细胞是短命的，并且通过几个定型和分化步骤不断地被由血液干细胞产生的新后代的平衡生产所取代。已知血细胞相对于其后代是静止的并且很少增殖。当它们这样做时，它们会产生更多的干细胞（自我更新）或分化后代。血液干细胞通过感知组织损伤并根据生理和应激诱导的需求调整后代，微调静止、自我更新和分化之间的平衡。就像一个舒适的家有助于家庭的幸福，工作环境影响员工的表现一样，造血干细胞在骨髓空间内特定位置的正确定位对于确保其正常功能至关重要。一些研究表明，造骨细胞，称为成骨细胞，在调节造血干细胞数量和功能方面具有重要作用;然而，少数旨在确定骨髓内造血干细胞位置的研究报告了广泛的位置，即使大多数观察到的细胞在成骨细胞附近，也只有少数细胞明显直接接触。由于在无脊椎动物模型生物体或不同哺乳动物组织中观察到的干细胞小生境通过干细胞和小生境细胞之间的直接相互作用发挥作用，因此出现了成骨细胞是否真正是血液干细胞小生境的主要组成部分的争议，只要存在这样的小生境。我最近开发了一种体内成像方法，使我能够在骨髓空间内观察移植的造血干细胞，然后立即将其注入血液，并且我可以“观察”相同细胞的行为，直到几天后。我收集的证据表明，在移植的造血干细胞中打开或关闭某些分子信号可以通过影响它们的定位来调节它们的功能。目前的建议旨在应用和进一步发展血液干细胞的体内成像，以获得关于血液干细胞生态位的存在，位置和功能的明确答案。我们将使用在所有成骨细胞中表达过度生理水平的Wnt抑制剂Dkk 1的转基因小鼠作为我们的工作模型，这些小鼠已被证明具有降低的造血干细胞功能，特别是自我更新能力。我们知道移植的造血干细胞在DKK骨髓中的定位异常，我们计划测试这种改变的定位是否是它们功能障碍的原因。我们将对移植的干细胞进行详细的延时跟踪，以询问与成骨细胞更接近的细胞是否比远离的细胞更静止（不太可能分裂），我们将利用新型光转换技术标记干细胞及其位于不同位置的后代，并随后比较它们的功能。此外，由于目前的体内成像技术不允许亚细胞分辨率，我们将研究是否可以使用来自正常或Dkk小鼠的造血干细胞和成骨细胞的共培养物作为替代系统，以更详细地研究在小鼠中观察到的至少一些事件，并且我们将使用它们来密切跟踪正常和不利条件下的造血干细胞行为和形态。我们将对来自自我更新允许或抑制培养物或小鼠的基质和干细胞进行全基因组表达分析，我们将专注于已知调节细胞-细胞和细胞-环境相互作用的基因。因此，我们将全面了解成骨细胞和血液干细胞之间的关系，我们将研究干细胞的位置是否直接影响功能，我们将了解什么分子参与了这一过程。

项目成果

Defining the in vivo characteristics of acute myeloid leukemia cells behavior by intravital imaging

• DOI: 10.1111/imcb.12216
• 发表时间: 2019-02-01
• 期刊: IMMUNOLOGY AND CELL BIOLOGY
• 影响因子: 4
• 作者: Duarte, Delfim;Amarteifio, Saoirse;Lo Celso, Cristina
• 通讯作者: Lo Celso, Cristina

Proliferation dynamics of acute myeloid leukaemia and haematopoietic progenitors competing for bone marrow space.

• DOI: 10.1038/s41467-017-02376-5
• 发表时间: 2018-02-06
• 期刊: Nature communications
• 影响因子: 16.6
• 作者: Akinduro O;Weber TS;Ang H;Haltalli MLR;Ruivo N;Duarte D;Rashidi NM;Hawkins ED;Duffy KR;Lo Celso C
• 通讯作者: Lo Celso C

Tracking single cells in live animals using a photoconvertible near-infrared cell membrane label.

• DOI: 10.1371/journal.pone.0069257
• 发表时间: 2013
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Carlson AL;Fujisaki J;Wu J;Runnels JM;Turcotte R;Spencer JA;Celso CL;Scadden DT;Strom TB;Lin CP
• 通讯作者: Lin CP

Inhibition of Endosteal Vascular Niche Remodeling Rescues Hematopoietic Stem Cell Loss in AML.

• DOI: 10.1016/j.stem.2017.11.006
• 发表时间: 2018-01-04
• 期刊: Cell stem cell
• 影响因子: 23.9
• 作者: Duarte D;Hawkins ED;Akinduro O;Ang H;De Filippo K;Kong IY;Haltalli M;Ruivo N;Straszkowski L;Vervoort SJ;McLean C;Weber TS;Khorshed R;Pirillo C;Wei A;Ramasamy SK;Kusumbe AP;Duffy K;Adams RH;Purton LE;Carlin LM;Lo Celso C
• 通讯作者: Lo Celso C

Subdivision of bone marrow microenvironments: purpose built homes for haematopoietic stem cells.

骨髓微环境的细分：专门为造血干细胞建造的家园。

• DOI: 10.1038/emboj.2012.337
• 发表时间: 2013
• 期刊: The EMBO journal
• 作者: Hawkins ED