PDF(Pubmed)
Abstract：
The musculoskeletal system is one of the most affected organs by aging that correlates well with an accumulation of senescent cells as for other multiple age-related pathologies. The molecular mechanisms underpinning muscle impairment because of senescent cells are still elusive. The availability of in vitro model of skeletal muscle senescence is limited and restricted to a small panel of phenotypic features of these senescent cells in vivo. Here, we developed a new in vitro model of senescent C2C12 mouse myoblasts that, when subjected to differentiation, the resulting myotubes showed sarcopenic features. To induce senescence, we used SYUIQ-5, a quindoline derivative molecule inhibitor of telomerase activity, leading to the expression of several senescent hallmarks in treated myoblasts. They had increased levels of p21 protein accordingly with the observed cell cycle arrest. Furthermore, they had enhanced SA-βgalactosidase enzyme activity and phosphorylation of p53 and histone H2AX. SYUIQ-5 senescent myoblasts had impaired differentiation potential and the resulting myotubes showed increased levels of ATROGIN-1 and MURF1, ubiquitin ligases components responsible for protein degradation, and decreased mitochondria content, typical features of sarcopenic muscles. Myotubes differentiated from senescent myoblasts cultures release increased levels of MYOSTATIN that could affect skeletal muscle cell growth. Overall, our data suggest that a greater burden of senescent muscle cells could contribute to sarcopenia. This study presents a well-defined in vitro model of muscle cell senescence useful for deeper investigation in the aging research field to discover new putative therapeutic targets and senescence biomarkers associated with the aged musculoskeletal system.
摘要：
肌肉骨骼系统是受衰老影响最大的器官之一，与其他多种年龄相关的病理一样，与衰老细胞的积累密切相关。由于衰老细胞而导致肌肉受损的分子机制仍然难以捉摸。骨骼肌衰老的体外模型的可用性是有限的，并且仅限于这些体内衰老细胞的一小部分表型特征。这里,我们开发了一种新的衰老C2C12小鼠成肌细胞体外模型，当受到分化时，由此产生的肌管表现出肌肉减少的特征。为了诱导衰老，我们使用SYUIQ-5，一种端粒酶活性的喹吲哚啉衍生物分子抑制剂，导致在治疗的成肌细胞中表达几种衰老标志。随着观察到的细胞周期停滞，它们的p21蛋白水平相应增加。Further,它们增强了SA-β半乳糖苷酶的活性以及p53和组蛋白H2AX的磷酸化。SYUIQ-5衰老成肌细胞的分化潜能受损，由此产生的肌管显示ATROGIN-1和MURF1水平升高，这些泛素连接酶是负责蛋白质降解的泛素连接酶，线粒体含量降低，肌肉减少症的典型特征。从衰老的成肌细胞培养物中分化出来的肌管释放的肌动蛋白水平升高，可能会影响骨骼肌细胞的生长。总的来说,我们的数据表明，衰老肌细胞的更大负担可能导致肌肉减少症。这项研究提出了一个定义明确的肌细胞衰老体外模型，可用于衰老研究领域的深入研究，以发现与衰老肌肉骨骼系统相关的新的推定治疗靶标和衰老生物标志物。
