Skeletal system contains various stem cell niches in which the self-renewal and differentiation of different kinds of stem cells are supported. Stem cell-based therapy has been applicated variedly. The skeletal stem cells (SSC), which are mesenchyme-derived and skeletal-lineage committed progenitors, can be found in the skeletal system. They are able to self-renew and colone both in vivo and in vitro. SSC have the potential of multi-directional differentiation to cartilage, bone, adipocytes and marrow stroma. Several types of SSC have been identified based on lineage tracing and single-cell RNA sequencing technique. Compared to mesenchymal stem cells, SSC are groups of less heterogeneous cells with accurate surface marker and identifiable biological behavior. Thus, clarifying the properties of SSC might provide new insight for stem cell therapy. In this article, the authors retrieved and reviewed SSC researches mainly focusing on the identification, spatio-temporal distribution and functional characteristics of SSC. The application of scRNA-seq in skeletal stem cell identification and functional study was also discussed.
骨骼系统中存在多种干细胞微环境，维持不同类型干细胞的自我更新与分化，其中包括了间充质来源的骨骼干细胞（skeletal stem cell，SSC）。它们在体内外均能自我更新和克隆形成，可多向分化形成软骨、骨、脂肪和骨髓基质。近年，随着谱系追踪和单细胞测序等技术的发展，不同类型的SSC被成功鉴定。相比于间充质干细胞的高异质性，SSC异质性更低、表面标志物可靠且生物学特性明确。因而，阐明SSC的特性，可为干细胞治疗提供新的思路。本文回顾SSC的研究进展，重点讨论SSC的特性、时间和空间分布差异以及功能异同。此外，还将讨论单细胞测序技术在SSC研究中的应用。.
Keywords: Cell lineage; RNA-sequencing; Single-cell analysis; Stem cell niche; Stem cells.