Lineage Determination and Tissue HomeOstasis in the aged Hematopoietic System

描述（由申请人提供）：造血涉及血细胞生产的紧密协调过程，并由少量造血干细胞（hsc）维持。与年轻人相比，老年人在包括造血系统在内的各种组织和器官中显示出基线功能和适应能力的大幅下降。据推测，随着年龄的增长，这些造血功能的变化是老年人贫血和免疫功能下降的潜在原因之一，特别是在压力下。确定造血干细胞及其后代积极参与造血的数量，并追踪单个造血干细胞对每种不同血细胞谱系的贡献，是确定组织稳态效率下降的细胞基础的重要一步。本研究的主要目标是在克隆水平上确定衰老后造血效率下降的细胞和分子基础，长期目标是将这些知识转化为改善甚至恢复造血系统中不必要的年龄相关表型的治疗方法。我们将使用新的克隆条形码技术对单个小鼠造血干细胞进行短期（4小时）转导（离体），用自我失活的慢病毒载体对大量造血干细胞进行单独标记，以确定造血系统中的克隆性、谱系测定和细胞周转，以及这些参数与衰老相关的变化。

DESCRIPTION (provided by applicant): Hematopoiesis involves the tightly coordinated process of blood cell production and is maintained by a small number of hematopoietic stem cells (HSCs). Compared to the young, the elderly show a substantial decline of baseline functions and adaptive capacity in various tissues and organs, including the hematopoietic system. It is assumed that these changes in hematopoiesis with age comprise one of the underlying causes for anemia and reduced immune function in the elderly, especially under stress. Resolving the number of HSCs and their progeny that actively contribute to hematopoiesis and tracking the contribution of individual HSCs to each of the different blood cell lineages is an important step to determine the cellular basis for decreased efficiency in tissue homeostasis. The primary goal of this study is to determine, on a clonal level, the cellular and molecular basis for decreased efficiency in hematopoiesis upon aging, with the long-term goal to translate this knowledge into therapies to ameliorate or even revert unwanted age-associated phenotypes in the hematopoietic system. We will use the novel technology of clonal barcoding of individual murine HSCs by short-term (4 hours) transduction (ex vivo) with self-inactivating lentiviral vectors to individually mark a multitude of HSCs to determine clonality, lineage determination and cell turnover in the hematopoietic system and the changes in these parameters associated with aging.