Characterization of Age-related Changes in Stem Cell Behavior

描述（由申请人提供）：干细胞在整个生命过程中提供器官和组织的维持和再生，组织（如血液和肌肉）再生能力的丧失归因于干细胞活性降低。干细胞促进组织稳态的能力取决于产生新干细胞（自我更新）以及特化细胞类型（分化）的独特能力。该提案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。我们还将研究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。研究方法：我们以前的特点是生殖系干细胞（GSC）的生态位在果蝇睾丸，提供了一个系统来研究内在和外在因素控制干细胞在体内的行为。在羽化后1、30和50天，分析来自与雌性一起维持的雄性睾丸的干细胞行为变化。使用现成的标记物，我们将分析基因表达和蛋白质表达的变化，并使用原位分析和免疫荧光定位在干细胞和小生境细胞。将使用BrdU掺入以及通过有丝分裂重组标记细胞来测定GSC分裂。将在野生型果蝇、JAK-STAT途径（其对于干细胞自我更新是必要且充分的）已被调节的果蝇以及已被表征为长寿的果蝇中分析GSC行为。结论：除了提供对组织稳态的见解，研究重点是干细胞及其专门的微环境中与年龄相关的变化，称为干细胞龛，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。简单总结：有证据表明，干细胞功能在衰老过程中下降，主要后果是组织功能丧失。组织替代疗法将严重依赖于在培养中扩增组织干细胞。该项目旨在描述干细胞和支持细胞中与年龄相关的变化，以促进培养中干细胞的扩增和维持，这是利用干细胞治疗与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.