Molecular regulation of native hematopoiesis

摘要 几十年的工作已经建立了一种基于 多能造血干细胞(HSCs)顶端的活性。我们对根本问题的理解 从历史上看，造血干细胞和祖细胞群体的特性都是基于 移植试验。然而，过去几年的数据对最根本的方面提出了挑战 并提出了与临床有直接关系的生物学问题。 血液学领域。此外，现在很明显，在看似纯净的人群中存在内在的异质性 造血干细胞和下游祖细胞的数量。这些在功能上截然不同的行为如何 干细胞/祖细胞是分子调控的，个体克隆大小是如何随着时间的推移而受到控制的 重要的生物学问题与我们对正常和疾病的造血的理解有关。超过了 在过去的五年里，我的实验室开发了新的基于单细胞的谱系追踪系统来研究造血 非移植个体的生物学，我们称之为天然造血。有了这些工具，我们 表明在造血细胞的来源和它们之间存在着重要的生物学差异 比较移植和天然血液生理学的结果。最近，我们已经将 谱系输出读数与单细胞水平的分子测量，使我们能够识别 具有不同功能结果的干细胞/祖细胞的转录特征。在这次更新中 应用程序，我们的目标是利用这些高分辨率的谱系追踪工具来进一步表征 天然造血中功能的HSC异质性与衰老。首先，我们将在功能上和 我们已经鉴定了一种新的天然HSC状态的转录调控因子 使用我们的单个细胞筛选器。第二，我们将利用单细胞谱系追踪的组合， 转录学和表观基因组学，以了解发生的分子变化和克隆波动 在小鼠的衰老过程中。第三，我们将调整我们的单细胞分子追踪策略，以 表征人类在替代天然状态下的造血，并确定潜在的新的调节因子 人类的HSC行为。我们的全面和跨学科的研究将在细胞和 原位造血的分子机制。此外，这些研究将为加强 促进造血再生，防止癌前克隆性造血。

SUMMARY Decades of work have established a paradigm for hematopoietic regeneration and maintenance based on the activity of multipotent hematopoietic stem cells (HSCs) at its apex. Our understanding of the fundamental properties of HSCs and progenitor populations has been historically based on notions derived from transplantation assays. Data over the last few years, however, have challenged the most fundamental aspects of models based on these studies, and have raised biological questions that are of direct clinical relevance in the hematology field. Additionally, it is now clear that intrinsic heterogeneity exists among seemingly pure populations of HSCs and downstream progenitors. How the functionally distinct behavior of these stem/progenitor cells is molecularly regulated and how individual clone size is controlled over time represent important biological questions relevant to our understanding of normal and diseased hematopoiesis. Over the past five years, my lab has developed novel single cell-based lineage tracing systems to study hematopoietic biology in the non-transplanted individual, which we refer to as native hematopoiesis. With these tools, we have shown that important biological differences exist between the source of hematopoietic cells and their outcomes when comparing transplantation versus native blood physiology. More recently, we have coupled lineage output readouts with molecular measurements at the single cell level, allowing us to identify transcriptional features of stem/progenitor cells that carry distinct functional outcomes. In this renewal application, we aim to utilize these high-resolution lineage-tracing tools to further characterize drivers of functional HSC heterogeneity and aging in native hematopoiesis. First, we will functionally and molecularly characterize a novel transcriptional regulator of the native HSC state, which we have identified using our singe cell screens. Second, we will utilize a combination of single cell lineage tracing, transcriptomics, and epigenomics to understand the molecular changes and clonal fluctuations that occur during the aging process in the mouse. Third, we will adapt our single cell molecular tracing strategies to characterize human hematopoiesis in a surrogate native state, and to identify potential novel regulators of human HSC behavior. Our comprehensive and interdisciplinary studies will shed led on the cellular and molecular mechanisms driving hematopoiesis in situ. Moreover, these studies will inform efforts to enhance hematopoietic regeneration and prevent pre-malignant clonal hematopoiesis.