Biomimetic Artificial Niche for Hematopoietic Stem Cell Expansion

描述（由申请人提供）：每年，超过30，000名患有血液疾病（如白血病、淋巴瘤、多发性骨髓瘤和重度再生障碍性贫血）的患者接受高剂量化疗，然后进行造血干细胞（HSC）移植。造血干细胞在移植后重建所有血液谱系的能力可以挽救这些患者的生命。然而，他们的需求远远超过他们的可用性 这是因为难以找到合适的供体匹配，加上它们的体外扩增潜力低。已经评估了多种培养条件用于HSC的体外扩增，但是由于培养物中分化的增加、干性的丧失和细胞周期异常的促进而取得了有限的成功。因此，本项目旨在开发新型仿生生物材料基底，并具有共存的小生境细胞促进HSC体外扩增的先天能力。目的1：开发一种模拟骨髓细胞外基质环境的生物材料基质，促进HSC体外扩增。目的2将研究是否存在Nestin阳性MSC的替代来源，其可用于体外扩增HSC。最后，目标3将确定额外的候选小生境细胞在体外促进HSC扩增中的作用。该提案将通过分析细胞表面受体、细胞骨架变化、可溶性因子、遗传变化和相关的细胞内途径来表征HSC扩增背后的分子机制，这是由于生物材料或与HSC一起培养的其他候选小生境细胞的影响。促进HSC扩增的创新方法可用于挽救生命的移植，以显著影响血液恶性肿瘤患者的预后。此外，该系统可作为研究小生境细胞-细胞相互作用、细胞-基质相互作用、药物筛选和遗传疾病的模型。这些研究将为骨髓微环境的知识基础做出重大贡献，并可能导致开发新的患者疗法，使他们能够活得更长，更充实。

DESCRIPTION (provided by applicant): Each year, over 30,000 patients suffering from hematological diseases such as leukemia, lymphoma, multiple myeloma, and severe aplastic anemia are treated with high-dose chemotherapy followed by hematopoietic stem cell (HSC) transplantations. The ability of HSCs to reconstitute all blood lineages post transplantation can be life-saving for these patients. However, their need is severely outweighed by their availability due to the difficulty in finding a suitable donor match coupled with their low expansion potential ex-vivo. A variety of culture conditions have been evaluated for in vitro expansion of HSCs but have yielded limited success due to an increase in differentiation, loss of stemness and promotion of cell cycle abnormalities in culture. Thus, this project aims to develop novel biomimetic biomaterial substrates and harbor the innate ability of co-existing niche cells to promote HSC expansion in vitro. Aim 1 will develop a biomaterial substrate to emulate the native bone marrow extracellular matrix environment and promote HSC expansion in vitro. Aim 2 will investigate if alternative sources of Nestin positive MSCs exist, which can be harnessed towards the expansion of HSCs in vitro. Finally, Aim 3 will determine the role of additional candidate niche cells in promoting HSC expansion in vitro. This proposal will characterize the molecular mechanisms behind HSC expansion due to the effects of the biomaterial or other candidate niche cells in culture with HSCs by analyzing cell surface receptors, cytoskeleton changes, soluble factors, genetic changes and associated intracellular pathways. Innovative methods for promoting HSC expansion could be used for life-saving transplantations to significantly impact the prognosis of patients with hematological malignancies. Additionally, this system can serve as a model for studying niche cell-cell interactions, cell-matrix interactions, drug screening and genetic diseases. These studies will significantly contribute to the knowledge base of the bone marrow niche microenvironment and potentially lead to the development of new patient therapies so they can live longer and more fulfilling lives.