Identifying the human skeletal stem cell.

项目摘要 本项目的主要目标是鉴定和表征人骨骼干细胞（hSSC） 以及其产生的骨、软骨和骨髓基质组织的谱系限制性祖细胞。 基于我们最近在Cell上发表的详细介绍小鼠SSC的文章，我们的最终目标是创建一个详细的 人类骨骼发生的谱系图，如在造血中所见，多能干细胞产生各种 在一个调节分化的生态位中的谱系。正如我们在小鼠研究中所证明的那样，我们将通过以下方式实现这一目标： 首先将人骨骼干细胞和祖细胞纯化至非常高水平的同质性（Aim 1），然后 其次通过检查细胞亚群的转录和翻译表达，最后 定义和探测干细胞和祖细胞之间的相互关系。因此，这些步骤将使 我们制定策略，如何操纵SSC利基，以推动骨，软骨或骨髓的命运决定 影响临床需求（目的2）。我们对mSSC利基监管的调查也使我们发现 骨形态发生蛋白-2、Wnt和VEGF的特定组合可以诱导从头形成 SSC甚至在非骨骼（脂肪）组织中。我们将探索类似的形态素组合是否也能诱导 hSSC形成和从丰富人脂肪基质从头产生骨、软骨或基质 人口（目标3）。 尽管小鼠模型的实用性，最近的报告描述了小鼠和人类之间的巨大差异 免疫学，这对新疗法的发展有直接影响。因此，为了真正 影响临床翻译，谨慎的做法是首先鉴定hSSC以鉴定保守的关键遗传途径 在小鼠和人类的骨骼发生，并揭示遗传机制之间的差异 老鼠和人类我们相信，我们在实施mSSC战略时获得的专业知识 使我们处于一个独特的位置，以表征人类对应的小鼠骨骼干细胞和祖细胞。 我们从胎儿和成人组织中获得的新的大量初步人类骨骼干/祖细胞数据强烈地表明， 确认我们方法的技术可行性和hSSC的存在。在此提出的实验 应用，如果得到支持，将为干细胞再生医学的实际翻译扫清道路， 骨骼疾病

Project Summary The primary goal of this proposed project is to identify and characterize the human skeletal stem cell (hSSC) and the lineage restricted progenitors of bone, cartilage, and bone marrow stromal tissues that it generates. Building on our recent publication in Cell detailing the mouse SSC, our ultimate objective is to create a detailed lineage map of human skeletogenesis, as seen in hematopoiesis, with a mulitpotent stem cell generating various lineages in a niche that regulates differentiation. As demonstrated in our mouse study, we will achieve this by first purifying human skeletal stem and progenitor cells to a very high level of homogeneity (Aim 1) and then secondly by examining the transcriptional and translational expression of the cellular subsets, before finally defining and probing the inter-relationship between the stem and progenitor cells. These steps will, thus, enable us to strategize how to manipulate the SSC niche to drive fate determination of bone, cartilage or bone marrow stroma to affect clinical need (Aim 2). Our investigation of the mSSC niche regulation also led us to discover specific combinations of bone morphogenetic protein-2, Wnt and VEGF that could induce de novo formation of SSC even in non-skeletal (adipose) tissue. We will explore if similar morphogen combinations could also induce hSSC formation and de novo generation of bone, cartilage, or stroma from plentiful human adipose stromal populations (Aim 3). Despite the utility of mouse models, recent reports describe dramatic differences between mouse and human immunology, which has a direct impact on the development of novel therapeutics. Therefore, in order to truly affect clinical translation, it is prudent to first identify the hSSC to identify key genetic pathways that are conserved in mouse and human skeletogenesis and to reveal the genetic mechanisms underlying differences between mouse and humans. We are confident that the expertise we acquired upon implementation of our mSSC strategy puts us in a unique position to characterize human counterparts of the mouse skeletal stem and progenitor cell. Our new substantial preliminary human skeletal stem/progenitor data from both fetal and adult tissue strongly affirm the technical feasibility of our approach and the existence of the hSSC. The proposed experiments in this application, if supported, would clear the path to practical translation of stem cell regenerative medicine for skeletal diseases.