Basic Aspects of Hematopoietic Stem Cells and Aging

项目总结： 造血和造血干细胞的变化是衰老的重要组成部分。 细胞端粒功能障碍在造血衰老中作用的研究进展 衰老和衰老相关分泌表型Sitruum家系的诱导 作用，线粒体代谢，雷帕霉素(MTOR)的机制靶点，在 免疫系统和由各种有毒实体引起的变化，其中许多涉及 使用高纯度的造血干细胞进行活性氧物种(ROS)检测 细胞。纯化小鼠造血干细胞的研究--以谱系阴性的c-DNA为例 有或没有CD150标记的KIT+SCA-1+(LSK)细胞表明，随着年龄的增长， 表型定义的干细胞的数量增加，而这些细胞的功能 减少，并发生髓系倾斜。许多关于老年人造血的工作都有 依赖于对纯化干细胞的研究，并基于这些细胞不是 骑自行车或休眠。然而，我们的工作表明，长期的多血统重新繁衍 在致命性照射的宿主中，细胞正在活跃地循环，并且总是在变化。这些发现的关键是 是对具有长期多谱系的完整未分离骨髓干细胞的研究 以植入法为检测手段。我们认为，到目前为止，大多数关于造血干细胞的研究都是 老化的人使用的是纯化的干细胞，这并不代表真正的骨髓干细胞 人口。我们建议在此研究内容、细胞周期状态和分化 未分离的小鼠骨髓干细胞在幼年、老年及雄性和老年小鼠中的特性 雌性老鼠。我们将细胞分离为G0、G1和S/G2/M组分，并评估植入情况。 我们还将利用氚胸苷自杀来评估非小细胞肺癌患者干细胞的周期状态。 分离骨髓和体内溴脱氧尿嘧啶核苷(BrdU)标记评估干细胞流量 细胞通过细胞周期。这些研究将为进一步研究提供重要的新基础。 衰老对造血干细胞的影响。

Project Summary: Changes in hematopoiesis and hematopoietic stem cells are an important component of aging. Many critical studies on the roles in hematopoietic aging of telomere dysfunction, cellular senescence and induction of the senescence-associated secretory phenotype, sitruin family effects, mitochondrial metabolism, the mechanistic target of rapamycin (mTOR), decline in the immune system and changes induced by a variety of toxic entities many of which involve Reactive Oxygen Species (ROS) were carried out employing highly purified hematopoietic stem cells. Studies on purified murine hematopoietic stem cells as exemplified by lineage negative c- kit+Sca-1+ (LSK) cells with or without CD150 marking, have indicated that with aging the number of phenotypically defined stem cells increases while the function of these cells decreases and myeloid skewing occurs. Much of the work on hematopoiesis in the aged has relied on studies of purified stem cells and is based on the assumption that these cells are non cycling or dormant. However, our work has shown that the long-term multi-lineage repopulating cell in lethally irradiated hosts is actively cycling and always changing. The key to these findings was the study of whole un-separated marrow stem cells with long-term multi-lineage engraftment as the assay. We feel that most studies to date on hematopoietic stem cells in aging have used purified stem cells, which are not representative of the true marrow stem cell populations. We propose here to study the content, cell cycle status and differentiation characteristics of un-separated marrow stem cells in young and aged mice and in male and female mice. We will separate cells into G0, G1 and S/G2/M fractions and evaluate engraftment. We will also utilize tritiated thymidine suicide to assess cycle status of stem cells in un- separated marrow and in vivo bromodeoxyuridine (BrdU) labeling to assess the flux of stem cells through cell cycle. These studies should give an important new base for further studies on the effects of aging on hematopoietic stem cells.