Mechanisms of Skeletal Muscle Satellite Cell Regulation in Aging

骨骼肌卫星细胞衰老调节机制

• 批准号: 7407788
• 负责人: David L. Mayhew
• 金额: $ 2.96万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-11-01 至 2010-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7407788
• 关键词: Accounting; Affect; Age; Aging; Apoptosis; Bromodeoxyuridine; Cell physiology; Cells; Condition; Crossover Design; Differentiation Antigens; Environment; Future; Goals; Human; Hypertrophy; In Situ Nick-End Labeling; In Vitro; Individual; Insulin-Like Growth Factor I; Interleukin-6; Mechanics; Mediating; Muscle; Natural regeneration; Phenotype; Process; Property; Public Health; Recruitment Activity; Regulation; Role; Serum; Skeletal Muscle Satellite Cells; Skeletal system; Staining method; Stains; Stem cells; Stretching; System; Techniques; Testing; Western Blotting; Work; age related; aged; frailty; improved; muscle hypertrophy; satellite cell; stem

DESCRIPTION (provided by applicant): The overall goal of this proposal is to identify the mechanisms by which an aging systemic environment is unable to recruit muscle specific stem cells, termed satellite cells (SCs), to contribute to skeletal muscle hypertrophy. The Aims of this proposal are two-fold: 1.) to separate the intrinsic properties of the SC proper from the effects of the milieu in aging, and 2.) to test the role of GH, IGF-I, TNF-a, and IL-6 on SC function in the context of the age of the milieu. The approach of Aim 1 will utilize a crossover design, with young primary human SC cultures separately receiving media containing young or old human serum. Likewise, old SCs will separately receive media containing young or old serum. To account for the influence of mechanical load, each media application will occur with cells under both cyclically stretched and unstretched conditions using a FlexCell system. The rationale for this approach is that decrements in SC function with age have been noted, but it is unknown whether these decrements are due to the SC proper or an altered milieu. Further, the interaction of the age of the systemic environment and mechanical load on SC phenotype is unknown. Each treatment group will be evaluated for proliferation (via BrdU incorporation), apoptosis (via TUNEL staining), differentiation (via Western blotting of differentiation markers), and fusion (via immunohistochemical techniques) of SC, which are reflective of the four processes necessary for SC mediated hypertrophy. The overall approach of Aim 2 is to manipulate levels of GH, IGF-I, TNF-a, and IL-6 in both young and old serum to determine the influence of each over proliferation, apoptosis, differentiation, and fusion of in vitro SCs isolated from old subjects. In addition, each serum treatment group will be analyzed in the stretched and un-stretched conditions. The rationale for this approach stems from the fact that several candidate molecules have been previously identified that affect SC function when applied in isolation, however the effect of these specific factors in the context of an aged in vitro environment under mechanical load has not been determined. Overall, these studies will improve our understanding of muscle hypertrophy in aging and will direct future efforts to combat age-related loss of muscle mass and frailty. Relevance to Public Health: This work will seek to determine the mechanisms by which muscle from aged individuals is unable to grow and regenerate to the same extent as muscle from the young. Identification of the mechanisms by which this phenomenon occurs will direct future efforts aimed at therapy for age-related loss of muscle mass.

描述（由申请人提供）：本提案的总体目标是确定老化系统环境无法招募肌肉特异性干细胞（称为卫星细胞（SCs））以促进骨骼肌肥大的机制。本研究的目的有两个方面：1)将SC固有的特性与环境对衰老的影响分离开来；2)在环境年龄的背景下，测试GH、IGF-I、TNF-a和IL-6对SC功能的作用。目的1的方法将采用交叉设计，将年轻的原代人SC培养物分别接受含有年轻或年老人血清的培养基。同样，老sc将分别接受含有年轻或年老血清的培养基。为了考虑机械载荷的影响，每种介质应用都将在使用FlexCell系统的循环拉伸和非拉伸条件下进行。这种方法的基本原理是，已经注意到SC功能随着年龄的增长而下降，但尚不清楚这些下降是由于SC本身还是环境的改变。此外，系统环境的年龄和机械负荷对SC表型的相互作用是未知的。每个治疗组将评估SC的增殖（通过BrdU掺入）、凋亡（通过TUNEL染色）、分化（通过分化标记物的Western blotting）和融合（通过免疫组织化学技术），这反映了SC介导的肥大所必需的四个过程。Aim 2的总体方法是操纵年轻和老年血清中GH、IGF-I、TNF-a和IL-6的水平，以确定它们对老年受试者体外分离SCs的增殖、凋亡、分化和融合的影响。并对各血清处理组在拉伸和未拉伸条件下进行分析。这种方法的基本原理源于这样一个事实，即先前已经确定了几个候选分子，这些分子在分离应用时影响SC功能，但是这些特定因素在机械负荷下老化的体外环境中的作用尚未确定。总的来说，这些研究将提高我们对衰老过程中肌肉肥大的理解，并将指导未来对抗与年龄相关的肌肉质量损失和虚弱的努力。与公共卫生相关：这项工作将试图确定老年人的肌肉无法像年轻人的肌肉一样生长和再生的机制。确定这种现象发生的机制将指导未来针对与年龄相关的肌肉质量损失的治疗工作。