Using spatial, single-cell genomic recording to investigate age-associated clonal hematopoiesis

项目总结： 造血主要发生在密集的骨髓环境中。它受复合体的调节 多种细胞类型之间的信号相互作用以维持平衡的血池和对损伤的反应 比如出血和感染。在衰老过程中，造血率下降，并形成克隆优势 称为克隆性造血，即少量的造血干/祖细胞(HSPC) 产生不成比例的大量血细胞。克隆性造血与 包括白血病在内的各种血液病。了解克隆性造血的方式和原因 随着年龄的增长，检查调节造血的关键细胞间通讯是至关重要的 在骨髓中。这一点尤其重要，因为骨骼的变化与年龄有关。 骨髓，细胞数量大幅减少，细胞类型组成大量移动，导致 对造血至关重要的细胞间信号网络的变化。在这里，我们将应用一种新的基因组 记录和成像技术，回忆录(通过光学原位增强诱变的记忆 ，以分析老化的骨髓环境如何改变HSPC细胞间信号和 会影响克隆性造血。我们将检验两个相反的假设：(1)克隆性造血是由 骨髓中HSPC细胞间信号的年龄相关变化；或者(2)克隆性 造血是HSPC内在变化的结果，这些变化允许它们逃离 细胞间信令网络。我们将确定衰老如何改变空间背景和细胞间信号 并影响其克隆扩增。我们将研究与年龄相关的自发性 突变扰乱了HSPC克隆性扩张的空间背景和细胞间信号。我们建议的研究 将确定单个HSPC及其细胞间的谱系关系和空间组织 在老化的骨髓中发出信号。我们的结果可以揭示新的细胞和分子参与者 克隆性造血可作为控制造血衰老和年龄相关的治疗靶点 疾病。更广泛地说，这项研究将提供一个实验和概念框架来分析 在造血学中空间定义的细胞间通讯。

Project Summary: Hematopoiesis primarily takes place within the dense milieu of the bone marrow. It is regulated by complex signaling interactions among multiple cell types to maintain a balanced blood pool and to respond to injuries such as bleeding and infection. During aging, hematopoiesis declines and develops clonal dominance, also known as clonal hematopoiesis, where a small number of hematopoietic stem and progenitor cells (HSPCs) produce a disproportionately large amount of blood cells. Clonal hematopoiesis has been associated with various types of hematologic disorders including leukemia. To understand how and why clonal hematopoiesis develops with age, it is crucial to examine the key intercellular communications that regulate hematopoiesis within the bone marrow. This is particularly important because of dramatic age-associated changes to the bone marrow where the cell number substantially decreases and the cell type composition massively shifts, leading to changes in the intercellular signaling network critical for hematopoiesis. Here, we will apply a new genomic recording and imaging technique, MEMOIR (Memory through Enhanced Mutagenesis with Optical In-situ Readout), to analyze how the aging bone marrow environment alters HSPC intercellular signaling and influences clonal hematopoiesis. We will test two opposite hypotheses: (1) clonal hematopoiesis is induced by age-associated changes to the intercellular signaling of HSPCs in the bone marrow; and alternatively (2) clonal hematopoiesis is the result of intrinsic changes in HSPCs that allow them to escape from the control of the intercellular signaling network. We will determine how aging alters the spatial context and intercellular signaling of HSPCs, and influences their clonal expansion. And we will investigate how age-associated spontaneous mutations perturb the spatial context and intercellular signaling of HSPC clonal expansion. Our proposed study will identify the lineage relationships and spatial organization of individual HSPCs as well as their intercellular signaling in the aging bone marrow. Our results can reveal new cellular and molecular players underlying clonal hematopoiesis that could be used as therapeutic targets to control hematopoietic aging and age-related diseases. More generally, this study will provide an experimental and conceptual framework for analyzing spatially defined intercellular communication in hematopoiesis.