Well-defined, modifiable hydrogel networks to unravel key parameters that control stem cell fate in the bone marrow.

明确的、可修改的水凝胶网络可以揭示控制骨髓中干细胞命运的关键参数。

• 批准号: 1763795
• 金额: --
• 依托单位: King's College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1763795
• 关键词: Well; defined; modifiable; hydrogel; networks

Two adult stem cell populations reside in the bone marrow: marrow stromal/mesenchymal stem cells (MSCs) and haematopoietic stem cells. The marrow has a unique mechanical environment, which is known to be modulated by physiological activity and disuse, as well as in response to disease and aging. Many cells in the body, including stem cells, are highly mechanoresponsive. Physical characteristic that are known to direct stem cell fate include topography, stiffness and the spacing and clustering of adhesive ligands. For example, culture of MSCs on surfaces of different stiffnesses will direct their fate down neurogenic, myogenic and osteogenic lineages in the absence of soluble factors. However, these phenomena have only been systemically explored in cells cultured on 2D surfaces, which do not replicate the 3D environment of native tissues. There are a number of reports on the bulk mechanical properties of bone marrow that have been determined from measurements of hydrostatic pressure and viscosity. However, very little is known about the local mechanical properties of the marrow at the scale at which a cell mechanically detects the stiffness of its local environment. Moreover, in vitro models that account for these 3D physical properties of the marrow allow researchers to ask fundamental questions on the effect of factors such as stiffness in directing stem cell fate and in the maintenance of haematopoiesis in health and disease. To address these questions, we will use a combination of fluorescent microscopy and atomic force microscopy (AFM)-based microindentation to characterise the mechanical environment of the stem cell niche in mouse bone marrow. The Gentleman lab has developed a novel PEG-peptide hydrogel, in which systematic modifications of hydrogel chemistry allow for precise control of hydrogel physical properties such as stiffness, adhesive ligand positioning and gel degradability. PEG-peptide hydrogels are also biocompatible, allowing for encapsulation of live cells, making these gels an ideal system to mimic the bone marrow in vitro. Therefore, we will also create PEG-peptide hydrogels with stiffnesses that match those of native bone marrow, encapsulate live cells, and examine how changes in the physical and mechanical properties on the marrow affects stem cell response in native tissue-like niches. This interdisciplinary project melds expertise in polymer synthesis, mechanobiology, peptide chemistry, stem cell biology and mechanics at KCL, UCL and Imperial to determine the mechanical properties of the bone marrow stem cell niche, and then create an in vitro model based on well-defined, peptide-modified hydrogels with modifiable physical and biological properties that mimics it. With this model, we will ask fundamental questions regarding how stem cells respond to physical properties of their environment. Overall, this project should provide fundamental insights into stem cell mechanobiology and the role of physical properties in the bone marrow stem cell niche in health and disease.

骨髓中存在两种成体干细胞群体：骨髓基质/间充质干细胞(MSCs)和造血干细胞。骨髓有一个独特的机械环境，众所周知，这种环境受到生理活动和停用的调节，以及对疾病和衰老的反应。身体中的许多细胞，包括干细胞，都是高度机械反应的。已知的决定干细胞命运的物理特征包括地形、硬度以及黏附配体的间距和聚集。例如，在不同硬度的表面培养间充质干细胞，在缺乏可溶性因素的情况下，它们的命运将沿着神经源性、肌源性和成骨性谱系进行。然而，这些现象只在2D表面培养的细胞中被系统地探索过，这并不能复制自然组织的3D环境。有许多关于骨髓的整体力学性质的报道，这些报道是通过测量静水压力和粘度来确定的。然而，在细胞机械地检测其局部环境的僵硬程度上，人们对骨髓的局部机械特性知之甚少。此外，解释骨髓这些3D物理特性的体外模型允许研究人员提出一些基本问题，比如在指导干细胞命运以及在健康和疾病中维持造血方面，僵硬等因素的影响。为了解决这些问题，我们将使用荧光显微镜和基于原子力显微镜(AFM)的微压痕相结合的方法来表征小鼠骨髓干细胞壁龛的机械环境。绅士实验室开发了一种新型的聚乙二醇多肽水凝胶，其中对水凝胶化学进行了系统的修改，允许精确控制水凝胶的物理性质，如硬度、粘合剂配体定位和凝胶降解性。聚乙二醇多肽水凝胶还具有生物相容性，可以包裹活细胞，使其成为在体外模拟骨髓的理想系统。因此，我们还将创造具有与天然骨髓相匹配的硬度的聚乙二醇肽水凝胶，包裹活细胞，并研究骨髓物理和机械特性的变化如何影响天然组织样壁龛中的干细胞反应。这个跨学科的项目融合了KCL、UCL和Imperial在聚合物合成、机械生物学、肽化学、干细胞生物学和力学方面的专业知识，以确定骨髓干细胞利基的机械性能，然后创建一个基于定义明确的多肽修饰水凝胶的体外模型，该水凝胶具有可修改的物理和生物特性来模拟它。在这个模型中，我们将提出有关干细胞如何对其环境的物理属性做出反应的基本问题。总体而言，该项目应该提供对干细胞机械生物学的基本见解，以及骨髓干细胞生态位中物理特性在健康和疾病中的作用。

项目成果

Selectively Cross-Linked Tetra-PEG Hydrogels Provide Control over Mechanical Strength with Minimal Impact on Diffusivity.

• DOI: 10.1021/acsbiomaterials.0c01723
• 发表时间: 2021-09-13
• 期刊: ACS biomaterials science & engineering
• 影响因子: 5.8
• 作者: Lust ST;Hoogland D;Norman MDA;Kerins C;Omar J;Jowett GM;Yu TTL;Yan Z;Xu JZ;Marciano D;da Silva RMP;Dreiss CA;Lamata P;Shipley RJ;Gentleman E
• 通讯作者: Gentleman E

Exploiting Advanced Hydrogel Technologies to Address Key Challenges in Regenerative Medicine.

• DOI: 10.1002/adhm.201700939
• 发表时间: 2018-04
• 期刊: Advanced healthcare materials
• 影响因子: 10
• 作者: Foyt DA;Norman MDA;Yu TTL;Gentleman E
• 通讯作者: Gentleman E