Characterization of Age-related Changes in Stem Cell Behavior

描述(申请人提供)：干细胞在一生中维持和再生器官和组织，而血液和肌肉等组织再生能力的丧失归因于干细胞活性的降低。干细胞促进组织动态平衡的能力取决于产生新干细胞(自我更新)和特化细胞类型(分化)的独特能力。这项建议的目的是分析衰老过程中干细胞行为的变化，并确定调节这些变化的分子机制。我们还将调查调节寿命的途径与干细胞和干细胞生态位的年龄相关变化之间的关系。方法：我们先前研究了果蝇睾丸中的生殖系干细胞(GSC)生态位，为研究体内控制干细胞行为的内在和外在因素提供了一个系统。在羽化后1天、30天和50天，将对雄性和雌性共同饲养的雄性睾丸进行干细胞行为变化分析。利用现成的标记物，我们将利用原位分析和免疫荧光技术分析干细胞和壁龛细胞中基因表达和蛋白表达的变化以及定位。GSC的分裂将通过BrdU掺入以及通过有丝分裂重组标记细胞来检测。GSC的行为将在野生型果蝇中进行分析，在野生型果蝇中，JAK-STAT途径是干细胞自我更新所必需的和充分的，在这些果蝇中，以及被特征为长寿命的果蝇中，GSC的行为将被分析。结论：除了提供对组织动态平衡的洞察外，专注于干细胞及其特殊微环境的年龄相关变化的研究将有助于识别和克服操纵来自老年患者的组织干细胞的独特障碍，并促进再生医学技术的发展，以治疗与衰老相关的疾病。总结：有证据表明，在衰老过程中干细胞功能下降，其主要后果是组织功能的丧失。组织替代疗法将在很大程度上依赖于培养中扩张的组织干细胞。该项目致力于描述干细胞和培养干细胞的支持细胞与年龄相关的变化，以促进干细胞在培养中的扩增和维持，这是利用干细胞治疗衰老相关疾病的重要第一步。

DESCRIPTION (provided by applicant): Stem cells provide for the maintenance and regeneration of organs and tissues throughout life, and loss of the regenerative capacity of tissues such as blood and muscle has been attributed to decreased stem cell activity. The ability of stem cells to contribute to tissue homeostasis depends on the unique ability to generate both new stem cells (self-renewal) as well as specialized cell types (differentiation). The Aims of this proposal are to analyze changes in stem cell behavior during the aging process and to identify molecular mechanisms regulating these changes. We will also investigate the relationship between pathways regulating longevity and age-related changes to stem cells and the stem cell niche. Methods: We previously characterized the germ line stem cell (GSC) niche in the Drosophila testis, providing a system to study the intrinsic and extrinsic factors controlling stem cell behavior in vivo. Testes from males maintained with females will be analyzed for changes in stem cell behavior at 1, 30, and 50 days post-eclosion. Using readily available markers, we will analyze changes in gene expression and protein expression and localization in stem cells and niche cells using in situ analysis and immunofluorescence. GSC division will be assayed using BrdU incorporation as well as by marking cells through mitotic recombination. GSC behavior will be analyzed in wild type flies, flies in which the JAK-STAT pathway, which is necessary and sufficient for stem cell self-renewal, has been modulated, and in flies that have been characterized as being long-lived. Conclusions: In addition to providing insights into tissue homeostasis, studies focusing on age-related changes in stem cells and their specialized microenvironments, known as stem cell niches, will help to identify and overcome unique hurdles in the manipulation of tissue stem cells derived from older patients and to facilitate the development of techniques for regenerative medicine to treat aging-related diseases. Lay Summary: Evidence suggests that stem cell function decreases during the aging process, and the primary consequence is loss of tissue function. Tissue replacement therapies will rely heavily on expanding tissue stem cells in culture. This project seeks to characterize age-related changes in stem cells and the support cells that nurture them to facilitate the expansion and maintenance of stem cells in culture, an essential first step in the utilization of stem cells to treat aging-related diseases.