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Skeletal muscle atrophy is a major health concern, severely affecting the patient's mobility and life quality. In the pathological process of skeletal muscle atrophy, with the progressive decline in muscle quality, strength, and function, the incidence of falling, fracture, and death is greatly increased. Unfortunately, there are no effective treatments for this devastating disease. Thus, it is imperative to investigate the exact pathological molecular mechanisms underlying the development of skeletal muscle atrophy and to identify new therapeutic targets. Decreased muscle mass, strength, and muscle fiber cross-sectional area are typical pathological features and manifestations of skeletal muscle atrophy. Ferroptosis, an emerging type of programmed cell death, is characterized by iron-dependent oxidative damage, lipid peroxidation, and reactive oxygen species accumulation. Notably, the understanding of its role in skeletal muscle atrophy is emerging. Ferroptosis has been found to play an important role in the intricate interplay between the pathological mechanisms of skeletal muscle atrophy and its progression caused by multiple factors. This provides new opportunities and challenges in the treatment of skeletal muscle atrophy. Therefore, we systematically elucidated the ferroptosis mechanism and its progress in skeletal muscle atrophy, aiming to provide a comprehensive insight into the intricate relationship between ferroptosis and skeletal muscle atrophy from the perspectives of iron metabolism and lipid peroxidation and to provide new insights for targeting the pathways related to ferroptosis and the treatment of skeletal muscle atrophy. [ABSTRACT FROM AUTHOR]

Obesity is a highly prevalent disease that can induce metabolic syndrome and is associated with a greater risk of muscular atrophy. Mitochondria play central roles in regulating the physiological metabolism of skeletal muscle; however, whether a decreased mitochondrial function is associated with impaired muscle function is unclear. In this study, we evaluated the effects of a high-fat diet on muscle mitochondrial function in a zebrafish model of sarcopenic obesity (SOB). In SOB zebrafish, a significant decrease in exercise capacity and skeletal muscle fiber cross-sectional area was detected, accompanied by high expression of the atrophy-related markers Atrogin-1 and muscle RING-finger protein-1. Zebrafish with SOB exhibited inhibition of mitochondrial biogenesis and fatty acid oxidation as well as disruption of mitochondrial fusion and fission in atrophic muscle. Thus, our findings showed that muscle atrophy was associated with SOB-induced mitochondrial dysfunction. Overall, these results showed that the SOB zebrafish model established in this study may provide new insights into the development of therapeutic strategies to manage mitochondria-related muscular atrophy. [ABSTRACT FROM AUTHOR]

Simple Summary: Excessive exercise can lead to muscle atrophy, which is particularly concerning in professional athletes. However, the effects of excessive exercise on the skeletal muscle system remain unclear. Here, we used a zebrafish model of excessive exercise to identify genes that are dysregulated during excessive exercise. We mapped the identified genes to regulatory networks to gain an understanding of their functions during muscle atrophy. We identified several important mechanisms by which excessive exercise can lead to muscle wasting and prevent regeneration. Our findings provide fundamental knowledge on the effect of overtraining on the skeletal muscle system, and will enable better monitoring of muscle condition in athletes. Long-term imbalance between fatigue and recovery may eventually lead to muscle weakness or even atrophy. We previously reported that excessive exercise induces pathological cardiac hypertrophy. However, the effect of excessive exercise on the skeletal muscles remains unclear. In the present study, we successfully established an excessive-exercise-induced skeletal muscle atrophy zebrafish model, with decreased muscle fiber size, critical swimming speed, and maximal oxygen consumption. High-throughput RNA-seq analysis identified differentially expressed genes in the model system compared with control zebrafish. Gene ontology and KEGG enrichment analysis revealed that the upregulated genes were enriched in autophagy, homeostasis, circadian rhythm, response to oxidative stress, apoptosis, the p53 signaling pathway, and the FoxO signaling pathway. Protein–protein interaction network analysis identified several hub genes, including keap1b, per3, ulk1b, socs2, esrp1, bcl2l1, hsp70, igf2r, mdm2, rab18a, col1a1a, fn1a, ppih, tpx2, uba5, nhlrc2, mcm4, tac1, b3gat3, and ddost, that correlate with the pathogenesis of skeletal muscle atrophy induced by excessive exercise. The underlying regulatory pathways and muscle-pressure-response-related genes identified in the present study will provide valuable insights for prescribing safe and accurate exercise programs for athletes and the supervision and clinical treatment of muscle atrophy induced by excessive exercise. [ABSTRACT FROM AUTHOR]