Hematopoietic Stem Cells (HSCs) as Juvenile Protective Factors that Alter Aging

造血干细胞 (HSC) 作为改变衰老的青少年保护因子

• 批准号: 7939836
• 负责人: DAVID E HARRISON
• 金额: $ 35.31万
• 依托单位: JACKSON LABORATORY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7939836
• 关键词: Adolescent; Adult; Age; Age-Months; Aging; Apoptosis; Apoptotic; BALB/cByJ Mouse; Biological Assay; Blood; Bromodeoxyuridine; Cell Aging; Cell Count; Cell physiology; Cells; Cellular Stress; Chromosomes; Clinical; Colony-forming units; DNA Double Strand Break; DNA Polymerase Inhibitor; DNA-Directed DNA Polymerase; Defect; Defense Mechanisms; Disease; Elderly; Embryo; Engraftment; Exposure to; Fetal Liver; Fetal Spleen; Flow Cytometry; Fluorescent Probes; Gamma Rays; Genome Stability; Genomic Instability; Growth Factor; Health; Hematopoiesis; Hematopoietic stem cells; Histones; Individual; Kidney; Label; Lesion; Longevity; Lymphoid; Marrow; Measures; Mediating; Mouse Strains; Mus; Myelogenous; Myeloid Cells; Nutrient; Oxygen; Paraquat; Pattern; Phenotype; Phosphorylation; Predisposition; Production; Proliferating; Propidium Diiodide; Public Health; Reactive Oxygen Species; Relative (related person); Site; Spectral Karyotyping; Spleen; Stem cell transplant; Stem cells; Techniques; Testing; Transplantation; age effect; aged; annexin A5; capsule; cell age; cell transformation; chemotherapy; comparative genomic hybridization; drinking water; exhaustion; fetal; human H2AX protein; improved; in vivo; irradiation; killings; precursor cell; prevent; programs; stem cell division; success; uptake

DESCRIPTION (provided by applicant): Detrimental effects of aging might be due in part to loss of juvenile protective factors, including stem cells. Murine hematopoiesis is ideal for investigating stem cells, because lineages of marrow and blood precursors can be measured with great precision. In BALB/cByJ (BALB) mice, the repopulating ability per hematopoietic stem cell (HSC) declines 20- to 50-fold with age, while in C57BL/6J (B6) mice, there is no such decline. Aims 1-3 test strain differences in HSC susceptibility to cellular stress in fetal liver and in marrow at 6 weeks plus 6, 12, 18 and 24 months of age, to determine if the B6-BALB differences are present in juveniles or if they slowly emerge with age. Long term (LT)-HSCs, short term (ST)-HSCs and common myeloid precursors (CMPs) will be identified by flow cytometry markers optimized for aging studies in these strains. Aim 4 tests whether transplants of intrinsic or extrinsic juvenile protective factors into aged mice will improve HSC function and increase lifespan. Understanding the factors and mechanisms of stem cell aging will help identify phenotypes in juveniles that predict functional defects in old age. Using these approaches, we will test the following hypotheses: Aim 1: That B6 cells maintain genomic stability better than BALB cells. LT-HSCs, ST-HSCs and CMPs from B6 and BALB mice will be exposed to treatments that cause genomic instability: gamma radiation, DNA polymerase inhibition, and paraquat. Genomic instability will be quantified as a) chromosome structural lesions (spectral karyotyping), b) segmental copy number aberrations (array comparative genomic hybridization), and c) DNA double strand breaks (histone H-2AX phosphorylation). Correlations of HSC functions with reactive oxygen species (ROS) and genomic instabilities will be tested. Aim 2: That B6 HSCs age less because they proliferate more slowly than BALB HSCs. HSC subpopulations will be assessed by a) rates of cell loss after exposure to 5-fluorouricil (5-FU) and b) uptake and dilution of bromodeoxyuridine (BrdU) after 1, 3, and 10 days in drinking water. Aim 3: That the rate of apoptosis is slower in B6 than in BALB. HSC subpopulations will be assessed by comparing proportions of apoptotic cells identified using dual labeling of Annexin V and propidium iodide. Aim 4: That young or fetal HSC grafts will benefit old BALB recipients. Young HSCs may out compete the repopulating functions of the defective HSCs in untreated old BALB recipients. If necessary, HSCs in old recipients will be mobilized by growth factors to open niches for young HSCs, or killed by irradiation or chemotherapy to both open niches and remove transformed cells. Potential extrinsic defects will be tested by transplanting fetal spleens (with genetically marked cells) into recipient kidney capsules. If microenvironments are damaged with age, more endogenous HSC renewal and production of differentiated cells will occur in the youthful microenvironment of the grafted spleens in old, compared to young, recipients. TO PUBLIC HEALTH The objectives of this program are to 1) identify mechanisms and factors that prevent the loss of hematopoietic stem cell (HSC) function with age in C57BL/6J mice but not in BALB/cByJ mice, and 2) test the benefits of transplanting youthful HSCs and microenvironments into old recipients. Potential long-term clinical benefits include the following: delayed exhaustion of HSCs; improving long-term health; increased long-term success of HSC transplants involving elderly donors or recipients; and improved treatments for diseases of aging that are mediated by the loss of stem cell or precursor cell function.

描述（由申请人提供）：衰老的有害影响可能部分是由于少年保护因子（包括干细胞）的丧失。鼠造血是研究干细胞的理想选择，因为可以很好地测量骨髓和血液前体的谱系。在BALB/CBYJ（BALB）小鼠中，每个造血干细胞（HSC）的再植物能力随着年龄的增长而下降20至50倍，而在C57BL/6J（B6）小鼠中，没有这样的下降。 AIMS在HSC易感性中的1-3个测试应变差异在胎儿肝脏中的细胞应激和6周的骨髓中，加6、12、18和24个月大，以确定少年中B6-BALB差异是否存在，还是随着年龄的增长而慢慢出现。长期（LT）-HSC，短期（ST）-HSC和常见的髓样前体（CMP）将通过优化这些菌株衰老研究的流式细胞仪标记来鉴定。 AIM 4测试内在的或外在的少年保护因子对老年小鼠的移植是否会改善HSC功能并增加寿命。了解干细胞衰老的因素和机制将有助于确定预测老年功能缺陷的少年中的表型。使用这些方法，我们将测试以下假设：目标1：B6细胞比BALB细胞更好地保持基因组稳定性。来自B6和BALB小鼠的LT-HSC，ST-HSC和CMP将暴露于引起基因组不稳定性的治疗：γ辐射，DNA聚合酶抑制和Paraquat。基因组不稳定性将被量化为a）染色体结构性病变（光谱核分型），b）分段拷贝数畸变（阵列比较基因组杂交）和c）DNA双链断裂（组蛋白H-2AX磷酸化）。将测试HSC功能与活性氧（ROS）和基因组不稳定性的相关性。目标2：B6 HSC年龄较小，因为它们比BALB HSC慢得多。 HSC亚群将通过a）暴露于5-氟尿嘧啶（5-FU）和b）在饮用水1、3和10天后的摄入和稀释率进行评估。 AIM 3：B6中凋亡率的速度慢于BALB。 HSC亚群将通过比较使用膜联蛋白V和碘化丙啶的双重标记鉴定的凋亡细胞的比例来评估。 AIM 4：年轻或胎儿HSC移植物将使旧的BALB接受者受益。年轻的HSC可能会竞争未经处理的旧BALB接受者中有缺陷的HSC的重现功能。如有必要，旧接受者中的HSC将被生长因子动员，以打开年轻HSC的壁ni，或通过对开放式壁ni的辐射或化学疗法杀死并去除转化的细胞。潜在的外部缺陷将通过将胎儿脾脏（带有遗传标记的细胞）移植到受体肾胶囊中来测试。如果微环境随着年龄的增长而损害，与年轻的接受者相比，在老年脾脏的年轻微环境中，将发生更多内源性HSC的更新，分化细胞的产生将发生。为了公共卫生，该计划的目标是1）确定C57BL/6J小鼠的机制和因素，以防止造血干细胞（HSC）的功能随着年龄的增长而丧失，但在BALB/CBYJ小鼠中不能丧失，而不是在BALB/CBYJ小鼠中进行测试，以及2）测试将年轻的HSC和微环境移植到老年人中的好处。潜在的长期临床益处包括以下内容：HSC延迟精疲力尽；改善长期健康；涉及老年捐助者或接受者的HSC移植物的长期成功；并改善了由干细胞或前体细胞功能丧失介导的衰老疾病的治疗方法。