Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
Adv Healthc Mater. 2019 Oct;8(20):e1900751. doi: 10.1002/adhm.201900751. Epub 2019 Sep 18.
Hematopoietic stem cells (HSCs) reside in the bone marrow within niches that provide microenvironmental signals in the form of biophysical cues, bound and diffusible biomolecules, and heterotypic cell-cell interactions that influence HSC fate decisions. This study seeks to inform the development of a synthetic culture platform that promotes ex vivo HSC expansion without exhaustion. A library of methacrylamide-functionalized gelatin (GelMA) hydrogels is used to explore remodeling and crosstalk from mesenchymal stromal cells (MSCs) on the expansion and quiescence of murine HSCs. The use of a degradable GelMA hydrogel enables MSC-mediated remodeling, yielding dynamic shifts in the matrix environment over time. An initially low-diffusivity hydrogel for co-culture of hematopoietic stem and progenitor cells to MSCs facilitates maintenance of an early progenitor cell population over 7 days. Excitingly, this platform promotes retention of a quiescent HSC population compared to HSC monocultures. These studies reveal MSC-density-dependent upregulation of MMP-9 and changes in hydrogel mechanical properties (ΔE = 2.61 ± 0.72) suggesting MSC-mediated matrix remodeling may contribute to a dynamic culture environment. Herein, a 3D hydrogel is reported for ex vivo HSC culture, in which HSC expansion and quiescence is sensitive to hydrogel properties, MSC co-culture, and MSC-mediated hydrogel remodeling.
造血干细胞 (HSCs) 存在于骨髓的龛位中，龛位以生物物理线索、结合和扩散生物分子以及异质细胞-细胞相互作用的形式提供微环境信号，这些信号影响 HSC 命运决定。本研究旨在为体外 HSC 扩增而不耗尽的合成培养平台的开发提供信息。使用一系列甲基丙烯酰胺功能化明胶 (GelMA) 水凝胶来探索间充质基质细胞 (MSCs) 在扩增和静止过程中对 HSCs 的重塑和串扰。可降解 GelMA 水凝胶的使用使 MSC 介导的重塑得以实现，随着时间的推移，基质环境发生动态变化。最初用于共培养造血干细胞和祖细胞与 MSCs 的低扩散性水凝胶有助于在 7 天内维持早期祖细胞群体。令人兴奋的是，与 HSC 单核培养相比，该平台促进了静止 HSC 群体的保留。这些研究揭示了 MSC 密度依赖性 MMP-9 的上调和水凝胶力学性能的变化（ΔE = 2.61 ± 0.72），表明 MSC 介导的基质重塑可能有助于动态培养环境。在此，报告了一种用于体外 HSC 培养的 3D 水凝胶，其中 HSC 的扩增和静止对水凝胶特性、MSC 共培养和 MSC 介导的水凝胶重塑敏感。
