Heaton Robert A, Ball Sam Tm, Staunton Caroline A, Mouly Vincent, Jones Samantha W, McArdle Anne, Jackson Malcolm J
MRC-Versus Arthritis Centre for Integrated Research Into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool L7 8TX, France.
Sorbonne Université, Inserm, Institut de Myologie, Centre de Recherche en Myologie, Paris, France.
Free Radic Biol Med. 2025 Feb 1;227:395-406. doi: 10.1016/j.freeradbiomed.2024.11.053. Epub 2024 Dec 4.
Skeletal muscle generates superoxide during contractions, which is converted to hydrogen peroxide (HO). HO has been proposed to activate signalling pathways and transcription factors that regulate adaptive responses to exercise, but the concentration required to oxidize and activate key redox-sensitive signalling proteins in vitro is much higher than the typical intracellular levels seen in muscle after exercise. We hypothesized that 2-Cys-peroxiredoxins (PRDX), which rapidly oxidize in the presence of physiological concentrations of HO, serve as intermediary signalling molecules and play a crucial role in activating adaptive pathways following muscle contractions. This study has examined the human muscle myotube responses to contractile activity, or exposure to low extracellular concentrations (2.5-5 μM) of HO and whether knock down of muscle PRDX2 alters the differential gene expression (DEG) that results from these stresses. Exposure of human skeletal muscle myotubes to a 15 min period of aerobic electrically stimulated isometric contractions or 5 μM HO induced substantial changes in DEG with modification of many genes associated with adaptations of skeletal muscle to contractile activity. Common DEG in these conditions included upregulation of genes associated with increased mitochondrial oxidative phosphorylation, including COX1, COX2, COX3 and ATP6. In myotubes with PRDX2 knock down (94 % decrease in PRDX2 mRNA), the upregulation of genes associated with increased mitochondrial oxidative phosphorylation was abolished following contractile activity or exposure to HO. These data indicate that a common effect of contractile activity and exposure to "physiological" levels of HO in human myotubes is to increase the expression of multiple genes associated with increased mitochondrial oxidative phosphorylation. Furthermore, these effects were abolished in PRDX2 knock down myotubes indicating that adaptations to upregulate multiple genes related to increased mitochondrial capacity in human muscle myotubes in response to exercise is both redox regulated and requires PRDX2 as an essential mediator of the effects of HO.
骨骼肌在收缩过程中产生超氧化物，超氧化物会转化为过氧化氢（H₂O₂）。有人提出H₂O₂可激活调节运动适应性反应的信号通路和转录因子，但在体外氧化并激活关键的氧化还原敏感信号蛋白所需的浓度远高于运动后肌肉中常见的细胞内水平。我们推测，在生理浓度的H₂O₂存在下能快速氧化的2-半胱氨酸过氧化物酶（PRDX）作为中间信号分子，在肌肉收缩后激活适应性通路中起关键作用。本研究检测了人类肌肉肌管对收缩活动的反应，或暴露于低细胞外浓度（2.5 - 5 μM）的H₂O₂时的反应，以及敲低肌肉PRDX2是否会改变这些应激导致的差异基因表达（DEG）。将人类骨骼肌肌管暴露于15分钟的有氧电刺激等长收缩或5 μM H₂O₂中，会诱导DEG发生显著变化，许多与骨骼肌对收缩活动适应性相关的基因发生了改变。这些条件下的常见DEG包括与线粒体氧化磷酸化增加相关的基因上调，如COX1、COX2、COX3和ATP6。在PRDX2敲低的肌管中（PRDX2 mRNA减少94%），收缩活动或暴露于H₂O₂后，与线粒体氧化磷酸化增加相关的基因上调被消除。这些数据表明，收缩活动和暴露于人类肌管中“生理”水平的H₂O₂的共同作用是增加多个与线粒体氧化磷酸化增加相关基因的表达。此外，这些效应在PRDX2敲低的肌管中被消除，表明人类肌肉肌管中响应运动而上调多个与线粒体能力增加相关基因的适应性既是氧化还原调节的，并且需要PRDX2作为H₂O₂效应的关键介质。
