ACTIVATION OF PURIFIED HEMATOPOIETIC STEM CELLS

纯化造血干细胞的激活

• 批准号: 2650018
• 负责人: PETER M LANSDORP
• 金额: $ 10.35万
• 依托单位: UNIVERSITY OF BRITISH COLUMBIA
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-30 至 1998-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2650018
• 关键词: CD34 molecule; bone marrow; cell growth regulation; cell proliferation; cell type; chromosomes; clone cells; dyserythropoietic anemia; embryo /fetus tissue /cell culture; enzyme inhibitors; fluorescent in situ hybridization; hematopoietic stem cells; human tissue; karyotype; leukemia; liver cells; neoplastic cell; neoplastic transformation; preneoplastic state; telomerase; telomere

Blood cells originate from a population of hematopoietic stem cells which are typically defined as pluripotent cells with self-renewal capacity. Although the regenerative capacity of the hematopoietic system is impressive, the replicative potential of stem cells nevertheless appears finite. Because the number of times stem cells can divide is an important consideration in the development of novel therapeutic strategies, including stem cell transplantation, ex vivo expansion and gene therapy, studies that may help define the replicative potential of stem cells are of general interest. Previous studies with purified human "candidate" stem cells have shown that their functional properties change dramatically during ontogeny, that loss in their proliferative potential correlates with measurable changes in the number of telomere repeats and that they express low levels of telomerase. Here we propose to study biological properties of normal and malignant hematopoietic stem cells in relation to telomerase expression and telomere length on individual chromosomes. For these studies, clonally propagated normal and leukemic precursor cells will be analyzed by novel quantitative fluorescence in situ hybridization techniques. The specific aims of the proposed studies are: 1) To analyze chromosome specific, replication-dependent telomere shortening in (sub-) clones of purified CD34+CD38- cells from fetal liver, cord blood and adult bone marrow; 2) to compare telomere karyograms of normal, myelodysplastic and leukemic cells from the same patient in order to study the role of telomeres in myelodysplastic disease and leukemic transformation; and 3) To study the expression of telomerase, telomerase mRNA and related factors in normal and malignant stem cell "candidates" in relation to their proliferative potential and examine the effect of telomerase inhibitors on chromosome specific telomere length and the proliferative properties of such cells. Taken together, these studies should clarify the role of telomeraes in the proliferation of normal and malignant hematopoietic stem cells and leukemia specific chromosomal abnormalities.

血细胞来源于一群造血干细胞 它通常被定义为具有自我更新能力的多能细胞 容量 虽然造血细胞的再生能力 干细胞的复制潜能 但似乎是有限的。 因为干的次数 细胞能否分裂是一个重要的考虑因素， 新的治疗策略，包括干细胞移植， 体外扩增和基因治疗，研究可能有助于定义 干细胞的复制潜能受到普遍关注。 先前对纯化的人类“候选”干细胞的研究 表明它们的功能特性在过程中发生显着变化 个体发育，其增殖潜力的丧失与 端粒重复序列数量的可测量变化， 它们表达低水平的端粒酶。 在这里，我们建议研究 正常和恶性造血干细胞的生物学特性 细胞端粒酶表达和端粒长度的关系， 单个染色体。 对于这些研究，克隆繁殖 正常和白血病前体细胞将通过新的 定量荧光原位杂交技术。 的 具体的研究目的是：1）分析 染色体特异性，复制依赖性端粒缩短， 来自胎肝、脐带血和胎牛血清的纯化CD 34 + CD 38-细胞的（亚）克隆 血液和成人骨髓; 2）比较端粒核型 正常的，骨髓增生异常和白血病细胞， 为了研究端粒在骨髓增生异常中的作用， 疾病和白血病转化;和3）研究 端粒酶、端粒酶mRNA及相关因素在胃癌中的表达 正常和恶性干细胞“候选者”， 检测端粒酶的作用 抑制剂对染色体特异性端粒长度和 这些细胞的增殖特性。 综合来看，这些研究 应该澄清端粒在正常增殖中的作用， 恶性造血干细胞和白血病特异性 染色体异常