Stem Cell Program, Boston Children's Hospital, Boston.
Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge.
Curr Opin Hematol. 2021 Jan;28(1):18-27. doi: 10.1097/MOH.0000000000000624.
In the last few decades, revolutionary advances in next-generation sequencing have led to single-cell lineage tracing technologies that now enable researchers to identify and quantify hematopoietic cell behavior with unprecedented detail. Combined readouts of cell lineage and cell state from the same cell mitigate the need to prospectively isolate populations of interest, and allow a system-level understanding of dynamic developmental processes. We will discuss the advantages and shortcomings of these technologies, the intriguing discoveries that stemmed from lineage tracing hematopoiesis at the single-cell level and the directions toward which the field is moving.
Single-cell lineage tracing studies unveiled extensive functional heterogeneity within discrete immunophenotypic populations. Recently, several groups merged lineage tracing with single-cell RNA sequencing to visualize clonal relationships directly on transcriptional landscapes without the requirement for prospective isolation of cell types by FACS. To study the cell dynamics of hematopoiesis, without perturbation in their native niche, researchers have developed mouse models with endogenous single-cell lineage tracing systems, which can simultaneously trace thousands of hematopoietic progenitor cells in a single mouse, without transplantation. The emerging picture is that multiple hematopoietic hierarchies coexist within a single individual, each with distinct regulatory features. These hierarchies are imprinted during development much earlier than previously predicted, persisting well into adulthood and even after injury and transplantation.
Clone-tracking experiments allow stem-cell researchers to characterize lineage hierarchies during blood development and regeneration. Combined with single-cell genomics analyses, these studies are allowing system-level description of hematopoiesis in mice and humans. Early exploratory studies have unveiled features with important implications for human biology and disease. VIDEO ABSTRACT.
在过去几十年中，下一代测序技术的革命性进步带来了单细胞谱系追踪技术，使研究人员能够以前所未有的细节识别和量化造血细胞的行为。从同一细胞中同时读取细胞谱系和细胞状态的信息，减轻了对有前途的感兴趣细胞群体进行前瞻性分离的需求，并允许对动态发育过程进行系统级理解。我们将讨论这些技术的优缺点、从单细胞水平追踪造血谱系所带来的有趣发现，以及该领域的发展方向。
单细胞谱系追踪研究揭示了离散免疫表型群体内广泛的功能异质性。最近，几个研究小组将谱系追踪与单细胞 RNA 测序相结合，直接在转录景观上可视化克隆关系，而无需通过 FACS 对细胞类型进行前瞻性分离。为了在不干扰其天然生态位的情况下研究造血细胞的动力学，研究人员开发了具有内源性单细胞谱系追踪系统的小鼠模型，这些模型可以在单个小鼠中同时追踪数千个造血祖细胞，而无需移植。新兴的图景是，多个造血层次结构在单个个体中共存，每个层次结构都具有不同的调节特征。这些层次结构在发育过程中比以前预测的更早地被印记，在成年期甚至在受伤和移植后仍能持续存在。
克隆追踪实验使干细胞研究人员能够在血液发育和再生过程中描述谱系层次结构。与单细胞基因组学分析相结合，这些研究正在允许对小鼠和人类的造血进行系统级描述。早期的探索性研究揭示了对人类生物学和疾病具有重要意义的特征。视频摘要。
