Functional consequences of stem and progenitor cell heterogeneity

总体项目摘要 造血干细胞和祖细胞（HSPC）库中的细胞异质性越来越受到关注。 正常造血的公认方面。单个细胞克隆之间的变异性有助于这些 异质细胞状态驱动功能结果的多样性。每个克隆人都有不同之处， 功能属性，这是由每个细胞的表观基因组脚本。在这里，我们提出了一个独特的克隆- 特定特征与遗传克隆突变特别相关。具体来说，细胞和表观遗传 发生突变的克隆的状态（原始克隆）将改变细胞结果。我们还 假设克隆多样性可能导致了疾病表型的高度可变性， 克隆造血（clonal hematopoiesis，CH）我们集结了四支造血专家团队， 研究人员利用单细胞基因组学来定义基因调控网络，以解决这一假设。使用 在多种模型中，我们评估了CH中影响Tet 2、Dnmt 3a 2和Asxl 1的最常见突变。 我们的动机假设和这些初步研究支持三个重点领域的调查：1。 表观遗传状态平衡起源克隆以通过CH突变转化，使细胞对克隆敏感。 优势; 2.携带基因突变的克隆将进一步表现出对外源刺激的不同反应 使克隆优势; 3.代谢适应经常发生在优势无性系中， 易受代谢药物的影响，以减少克隆负担。总的来说，这些研究将提供详细的 评估造血克隆如何成为主导，分子标记是否可用于 预测CH背景下的克隆行为，以及低强度、代谢集中的策略是否可以 发展到削弱竞争力的克隆。

OVERALL PROJECT SUMMARY Cellular heterogeneity within the hematopoietic stem and progenitor cell (HSPC) pool is an increasingly recognized aspect of normal hematopoiesis. Variability among individual cell clones contributes to these heterogenous cellular states driving diversity of functional outcomes. Each clone bears differences across these functional attributes, which is scripted by the epigenome of each cell. Here, we propose that distinctive clone- specific features are particularly relevant to genetic clonal mutations. Specifically, the cellular and epigenetic state of the clone in which a mutation occurs (the clone-of-origin) will alter cellular outcomes. Further, we hypothesize that clonal diversity may contribute to the highly variable penetrance of a disease phenotype in the context of clonal hematopoiesis (CH). We have assembled four teams of hematopoiesis experts and a pioneering investigator in defining gene regulatory networks utilizing single-cell genomics to address this hypothesis. Using a variety of models, we have evaluated the most common mutations in CH affecting Tet2, Dnmt3a2 and Asxl1. Our motivating hypothesis and these preliminary studies support three focused areas of investigation: 1. Epigenetic states poise the clone-of-origin for transformation by CH mutations, sensitizing cells for clonal dominance; 2. Clones bearing a genetic mutation will exhibit divergent responses to exogenous stimuli further enabling clonal dominance; 3. Metabolic adaptation frequently occur in dominant clones rendering them vulnerable to metabolic drugs to reduce clonal burden. Collectively, these studies will provide a detailed assessment of how hematopoietic clones become dominant, whether molecular signatures can be used to predict clonal behavior in the setting of CH and whether low intensity, metabolism focused strategies can be developed to impair competitively advantaged clones.