Declining DNA repair in Aging Hematopoietic Stem Cell

衰老造血干细胞 DNA 修复能力下降

• 批准号: 6847369
• 负责人: STANTON L. GERSON
• 金额: $ 32.35万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-30 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6847369
• 关键词: DNA damage; DNA repair; DNA replication; RNA interference; aging; blood tests; cell age; cell cycle; cellular pathology; clinical research; cytogenetics; flow cytometry; fluorescent in situ hybridization; hematopoietic stem cells; human genetic material tag; human middle age (35-64); human old age (65+); human subject; immunocytochemistry; immunomagnetic separation; oxidative stress; phenotype; telomerase; tissue resource /registry; western blottings

DESCRIPTION (provided by applicant): The aging process is associated with deterioration of the stem cell pool leading to organ failure and dysfunction. Animal models indicate a critical role for DNA repair in the maintenance of the hematopoietic stem cell phenotype. For instance, loss of mismatch repair or double strand break end-joining leads to a competitive repopulation defect and gradual stem cell failure. In mice defective in the ATM gene, and nucleotide excision repair, hematopoietic stem cell dysfunction has also been observed. Likewise, purified hematopoietic stem cells overexpress the mismatch repair protein, MSH-2 and the DNA repair scaffold, XRCC-1. As humans age, the stem cell phenotype changes, with gradual loss of stem cell numbers, regenerative potential and stress response. This proposal will evaluate the hypothesis that loss of genomic stability is an inexorable part of the aging process and is measurable by examining DNA repair pathways and function leads to loss of the stem cell phenotype, loss of regeneration potential and loss of appropriate stress responses. Clinical syndromes that accelerate during aging including anemia, marrow failure yielding mono and pancytopenia, immune dysregulation, myelodysplastic syndromes and leukemias may all have as a common etiology progressive loss of DNA repair capacity in hematopoietic stem cells, as has been observed in animal models. This proposal will develop multiplex assays of a broad range of DNA repair proteins, perform careful assessment of Hematopoietic Stem Cell phenotype and function, and optimize microassays of DNA repair processes in freshly isolated, purified Hematopoietic Stem Cells before and after DNA damage perturbation from the aging population in the decades of 50 to 90. These studies will serve as the prototype with which to analyze normal aging and the diseases associated with aging of hematopoietic stem ceils. Furthermore, these processes undoubtedly affect other tissue stem cells and these approaches may have broad application across stem cell types. These studies will provide the basis to further analysis of DNA repair processes during the aging of stem cells to identify stem cell deficit disorders, response to chemotherapy and other stresses of hematopoietic stem cells land the relation ship between DNA repair processes and stem cell function as measured by conventional and novel assays developed under this RFA.

描述(申请人提供)：衰老过程与干细胞库的恶化有关，导致器官衰竭和功能障碍。动物模型表明DNA修复在维持造血干细胞表型方面起着关键作用。例如，错配修复或双链断裂末端连接的丢失会导致竞争性再繁殖缺陷和逐渐的干细胞衰竭。在ATM基因缺陷和核苷酸切除修复缺陷的小鼠中，也观察到了造血干细胞功能障碍。同样，纯化的造血干细胞过表达错配修复蛋白MSH-2和DNA修复支架XRCC-1。随着人类年龄的增长，干细胞表型发生变化，干细胞数量、再生能力和应激反应逐渐丧失。这项建议将评估这样一种假设，即基因组稳定性的丧失是衰老过程中不可避免的一部分，并且可以通过检查DNA修复途径和功能来衡量，这会导致干细胞表型丧失、再生潜力丧失和适当的应激反应丧失。在衰老过程中加速的临床症状，包括贫血、骨髓衰竭导致单核细胞和全血细胞减少、免疫调节失调、骨髓增生异常综合征和白血病，都可能是一种常见的病因，如在动物模型中观察到的那样，造血干细胞DNA修复能力的进行性丧失。 这项建议将开发广泛的DNA修复蛋白的多重分析，对造血干细胞的表型和功能进行仔细的评估，并优化新鲜分离、纯化的造血干细胞在50到90岁的老龄化人口DNA损伤扰动前后的DNA修复过程的微量分析。这些研究将作为分析正常衰老和与造血干细胞衰老相关的疾病的原型。此外，这些过程无疑会影响其他组织干细胞，这些方法可能会在不同类型的干细胞中广泛应用。 这些研究将为进一步分析干细胞老化过程中的DNA修复过程提供基础，以确定干细胞缺陷性疾病、对化疗和其他应激的反应，以及通过在该RFA下开发的传统和新的分析方法来测量DNA修复过程和干细胞功能之间的关系。