New tools for investigating mitochondrial dynamics in stem cells during aging

研究衰老过程中干细胞线粒体动力学的新工具

• 批准号: 9320723
• 负责人: DANA LEANNE JONES
• 金额: $ 19.25万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2018-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9320723
• 关键词: Address; Adult; Age; Age of Onset; Aging; Alpha Cell; Animals; Autophagocytosis; Biogenesis; Blood; Cell Culture Techniques; Cell Therapy; Cell physiology; Cells; Cellular Structures; Cessation of life; Chimeric Proteins; Complex; DNA; Data; Disease; Drosophila genus; Drosophila melanogaster; Electron Microscopy; Exocytosis; F-Actin; Frequencies; Generations; Genes; Germ Cells; Germ Lines; Homeostasis; Hormones; Imaging Techniques; Incidence; Individual; Insulin; Intestines; Investigation; Label; Life; Link; Liver; Location; Longevity; Maintenance; Mammals; Metabolic Diseases; Metabolism; Microscopy; Mitochondria; Mitochondrial Proteins; Mitotic; Morphology; Muscle; Nanotubes; Onset of illness; Organelles; Patients; Peroxidases; Physiological; Population; Production; Proteins; Publishing; RNA Interference; Regenerative Medicine; Reporter; Reporting; Signal Pathway; Skin; Somatomedins; Stem cells; Structure; Supporting Cell; System; Techniques; Technology; Testis; Time; Tissues; Transgenic Organisms; VP 16; adult stem cell; age effect; age related; ascorbate; base; cell behavior; cell type; environmental intervention; fly; gene therapy; genetic approach; germline stem cells; in vivo; insight; light microscopy; male; microvesicles; neuronal cell body; novel; public health relevance; repaired; response; segregation; self-renewal; stem cell niche; tissue regeneration; tool; tool development; trafficking; transmission process

 DESCRIPTION (provided by applicant): Adult stem cells support tissue homeostasis and serve as a cellular reservoir for repair of damaged tissue throughout the life of an individual. However, maintenance and regeneration of tissues such as skin, liver, blood, and muscle decrease dramatically with age. The inability of stem cells to adequately replace aging and damaged tissues is likely a significant contributing factor to age-related decreases in tissue homeostasis and increased incidence of disease. Therefore, it is essential to identify and characterize mechanisms leading to loss of stem cell function, in the context of aging, as strategies to delay or counter loss of stem cell function in older individuals will likely become a important component of regenerative medicine in years to come. Organismal aging is linked to altered metabolism at many levels- from changes in the quantity of extrinsic, systemic factors (ex. hormones, insulin/Insulin-like growth factors) to decreased efficiency of cellular organelles, such as mitochondria. Published data from our lab suggested that enhanced mitochondrial biogenesis in Drosophila melanogaster intestinal stem cells (ISCs) is sufficient to increase lifespan and delay the age-related decline in tissue homeostasis, in both the intestine and male germ line. However, many fundamental questions were raised by these studies. For example, if enhanced mitochondrial biogenesis in stem cells is sufficient to delay tissue aging, what strategies are used by stem cells to maintain a healthy pool of mitochondria? Addressing the links between metabolism, stem cell behavior, tissue homeostasis, and aging is difficult and complex in mammals yet more straightforward in Drosophila, given a relatively short lifespan, conserved signaling pathways that regulate aging and metabolism in mammalian systems, and several discrete populations of adult stem cells. Our preliminary data suggest that maintenance of germline stem cells (GSCs) in the testis of adult Drosophila melanogaster is dependent upon adequate mitochondrial fission and fusion within these cells. Furthermore, we have evidence that GSCs traffic mitochondria to adjacent, post- mitotic, somatic niche cells (hub cells). The frequency of transfer appears to increase with age; therefore, we hypothesize that transfer occurs as one mechanism for GSCs to dispose of damaged mitochondria. Here, I propose to combine cutting-edge electron microscopy (EM) imaging techniques with traditional genetic approaches in Drosophila melanogaster to provide unprecedented insight into the organization, segregation, and structure of mitochondria and mitochondrial proteins in stem cells in intact tissues. In addition to addressing questions regarding mitochondrial transfer, these tools will facilitate analyzing the location and function of many mitochondrial proteins in more detail. Our findings will have major implications for the use of cell-based therapies in the treatment of age-onset and metabolic diseases, particularly in older individuals.

 描述（由申请人提供）：成体干细胞支持组织稳态，并在个体的整个生命过程中作为修复受损组织的细胞库。然而，皮肤、肝脏、血液和肌肉等组织的维持和再生随着年龄的增长而急剧下降。干细胞不能充分替代老化和受损的组织可能是与年龄相关的组织稳态下降和疾病发病率增加的重要因素。因此，在衰老的背景下，识别和表征导致干细胞功能丧失的机制至关重要，因为延迟或对抗老年人干细胞功能丧失的策略可能会在未来几年成为再生医学的重要组成部分。 器官衰老与许多水平的代谢改变有关-从外在的系统因素的数量变化（例如，激素、胰岛素/胰岛素样生长因子）降低细胞器的效率， 例如线粒体。我们实验室发表的数据表明，在果蝇肠道干细胞（ISCs）中增强线粒体生物发生足以增加寿命并延缓肠道和雄性生殖系中与年龄相关的组织稳态下降。然而，这些研究提出了许多基本问题。例如，如果干细胞中增强的线粒体生物合成足以延缓组织衰老，那么干细胞使用什么策略来维持健康的线粒体库？ 解决代谢，干细胞行为，组织稳态和衰老之间的联系在哺乳动物中是困难和复杂的，但在果蝇中更直接，考虑到相对较短的寿命，在哺乳动物系统中调节衰老和代谢的保守信号通路，以及几个离散的成体干细胞群体。我们的初步数据表明，生殖系干细胞（GSC）在成年果蝇睾丸中的维持依赖于这些细胞内足够的线粒体分裂和融合。此外，我们有证据表明GSC将线粒体运输到相邻的有丝分裂后的体细胞小生境细胞（枢纽细胞）。转移的频率似乎随着年龄的增长而增加;因此，我们假设转移是GSC处理受损线粒体的一种机制。在这里，我建议结合联合收割机先进的电子显微镜（EM）成像技术与传统的遗传学方法在果蝇提供前所未有的深入了解组织，分离和结构的线粒体和线粒体蛋白质的干细胞在完整的组织。除了解决有关线粒体转移的问题外，这些工具还将有助于更详细地分析许多线粒体蛋白的位置和功能。我们的研究结果将对使用基于细胞的疗法治疗年龄发作和代谢疾病，特别是老年人的疾病产生重大影响。