Department of Biology, University of Wisconsin-La Crosse, La Crosse, WI, United States of America.
PLoS One. 2020 Sep 17;15(9):e0239047. doi: 10.1371/journal.pone.0239047. eCollection 2020.
Muscle aging is accompanied by blunted muscle regeneration in response to injury and disuse. Oxidative stress likely underlies this diminished response, but muscle redox sensors that act in regeneration have not yet been characterized. Calmodulin contains multiple redox sensitive methionines whose oxidation alters the regulation of numerous cellular targets. We have used the CRISPR-Cas9 system to introduce a single amino acid substitution M109Q that mimics oxidation of methionine to methionine sulfoxide in one or both alleles of the CALM1 gene, one of three genes encoding the muscle regulatory protein calmodulin, in C2C12 mouse myoblasts. When signaled to undergo myogenesis, mutated myoblasts failed to differentiate into myotubes. Although early myogenic regulatory factors were present, cells with the CALM1 M109Q mutation in one or both alleles were unable to withdraw from the cell cycle and failed to express late myogenic factors. We have shown that a single oxidative modification to a redox-sensitive muscle regulatory protein can halt myogenesis, suggesting a molecular target for mitigating the impact of oxidative stress in age-related muscle degeneration.
肌肉衰老伴随着损伤和废用后肌肉再生能力的减弱。氧化应激可能是这种反应减弱的基础，但参与再生的肌肉氧化还原传感器尚未被描述。钙调蛋白包含多个氧化还原敏感的蛋氨酸，其氧化会改变对许多细胞靶标的调节。我们使用 CRISPR-Cas9 系统在编码肌肉调节蛋白钙调蛋白的三个基因之一的 CALM1 基因的一个或两个等位基因中引入了单个氨基酸取代 M109Q，该取代模拟蛋氨酸到蛋氨酸亚砜的氧化，在 C2C12 小鼠成肌细胞中。当被信号指示进行肌发生时，突变的成肌细胞无法分化为肌管。尽管存在早期肌生成调节因子，但在一个或两个等位基因中具有 CALM1 M109Q 突变的细胞无法退出细胞周期，并且无法表达晚期肌生成因子。我们已经表明，对氧化还原敏感的肌肉调节蛋白的单个氧化修饰可以阻止肌发生，这为减轻与年龄相关的肌肉退化中氧化应激的影响提供了一个分子靶标。
