The AMPK/ULK1/p27Kip1 axis regulates autophagy and cell survival in aged satellite cells

A.项目摘要/摘要： 骨质疏松症是与年龄相关的骨骼肌质量和力量的丧失；它会导致一系列的共病。 包括身体功能和整体恢复能力的丧失。石棺减少症患者的一种这样的不安是 肌肉受伤后再生肌肉的能力减弱。肌肉干细胞，被称为卫星细胞，是 激活、增殖和分化所需，以再生肌肉和恢复身体功能。老态 卫星细胞在损伤时激活较慢；容易发生凋亡；修复损伤的效率较低 肌肉。AMPK/ULK1/p27Kip1通路似乎是从静止状态成功过渡到进入状态的关键 进入细胞周期。我们的初步数据确定了AMPK/ULK1/p27Kip1通路中的扰动 年事已高。这个获奖期将调查AMPK/ULK1/p27Kip1通路在 人和小鼠模型中卫星细胞老化的表型。在Aim1中，我们将测试假设 AMPK及其下游靶点ULK1和p27Kip1的激活调节自噬/凋亡的决定 在老化的卫星细胞中。我们将使用分子分析来挽救衰老细胞中这一途径的功能丧失。 并恢复增殖能力。在目标2中，我们将检验这样一种假设，即锻炼，一种生理诱因 AMPK和自噬，刺激AMPK/ULK1/p27Kip1通路，从而促进细胞增殖和 老化的小鼠和人类卫星细胞的代谢功能。目标3将检验这一假设 AMPK/ULK1/p27Kip1信号通路将调节热量限制对衰老卫星细胞的有益影响。 总之，本提案中的实验将检验AMPK/ULK1/p27Kip1途径是 在老化的卫星细胞中受损，导致自噬减少和对凋亡的敏感性。钥匙 怀特博士职业生涯的提升方面将是：学习如何协调临床运动试验；培训 在卫星细胞分离和代谢分析方法中，特别是在老化生物体的背景下。 培训计划将包括专门的内部和外部科学报告；中肯的课程 干细胞生物学和老龄化方面的工作/讲习班；以及密集的职业指导，以确保在以下方面取得进展 独立。本提案中详述的研究和职业发展计划将以 优秀的导师团队。威廉·E·克劳斯博士，杜克医学院的教授，是一位老牌的 临床运动研究和肌肉/卫星细胞生物学方面的专家；他将担任主要导师。戴维斯博士。 肯尼斯·施马德、黛博拉·穆约(杜克大学)和艾米·韦杰斯(哈佛大学)将担任共同导师；他们将 促进衰老生物学、细胞新陈代谢和衰老干细胞生物学方面的培训。环境问题 杜克医学院是开展这项提议中概述的研究和培训活动的理想选择。这 该奖项将为怀特博士提供最佳的培训，以确保他的职业生涯有一个出色的开端 独立调查员。

a. Project summary/abstract: Sarcopenia is the age-related loss in skeletal muscle mass and strength; it leads to a host of co-morbidities including loss of physical function and overall resilience. One such perturbation in persons with sarcopenia is the diminished ability to regenerate muscle after injury. Muscle stem cells, referred to as satellite cells, are required to activate, proliferate and differentiate to regenerate muscle and restore physical function. Aged satellite cells are slower to activate upon injury; susceptible to apoptosis; and less efficient in repairing injured muscle. The AMPK/ULK1/p27Kip1 pathway appears critical for successful transition from quiescence to entry into the cell cycle. Our preliminary data identify perturbations in the AMPK/ULK1/p27Kip1 pathway with advanced age. This award period will investigate the role of the AMPK/ULK1/p27Kip1 pathway in the phenotype of satellite cell aging in both human and mouse models. In Aim1, we will test the hypothesis that activation of AMPK and its downstream targets ULK1 and p27Kip1 regulate the autophagy/apoptosis decision in aged satellite cells. We will use molecular assays to rescue the functional loss of this pathway in aged cells and return proliferative capacity. In Aim 2, we will test the hypothesis that exercise, a physiological inducer of AMPK and autophagy, stimulates the AMPK/ULK1/p27Kip1 pathway, thereby enhancing proliferation and metabolic function in aging murine and human satellite cells. Aim 3 will test the hypothesis that AMPK/ULK1/p27Kip1 signaling will regulate the beneficial effects of caloric restriction on aged satellite cells. Together, the experiments in this proposal will test the hypothesis that the AMPK/ULK1/p27Kip1 pathway is impaired in aging satellite cells resulting in a reduction in autophagy and susceptibility to apoptosis. Key aspects of Dr. White's career enhancement will be: to learn how to coordinate clinical exercise trials; to train in methods of satellite cell isolation and metabolic analysis, especially in the context of the aging organism. The training program will entail dedicated internal and external scientific presentations; pertinent course work/workshops in stem cell biology and aging; and intensive career mentorship to ensure progress toward independence. The research and career development plan detailed in this proposal will be conducted with a team of outstanding mentors. Dr. William E. Kraus, a professor at the Duke Medical School is an established expert in clinical exercise studies and muscle/satellite cell biology; he will serve as the primary mentor. Drs. Kenneth Schmader, Deborah Muoio (Duke) and Amy Wagers (Harvard) will serve as co-mentors; they will facilitate training in aging biology, cell metabolism and aging stem cell biology, respectively. The environment at the Duke School of Medicine is ideal for the research and training activities outlined in this proposal. This award will provide Dr. White with optimal training to ensure an outstanding start to his career as an independent investigator.