School of Health, Medical and Applied Sciences, Central Queensland University, Rockhampton, Queensland, Australia.
Bond Institute of Health and Sport, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland, Australia.
PLoS One. 2022 Sep 1;17(9):e0273925. doi: 10.1371/journal.pone.0273925. eCollection 2022.
Skeletal muscle unloading due to joint immobilization induces muscle atrophy, which has primarily been attributed to reductions in protein synthesis in humans. However, no study has evaluated the skeletal muscle proteome response to limb immobilization using SWATH proteomic methods. This study characterized the shifts in individual muscle protein abundance and corresponding gene sets after 3 and 14 d of unilateral lower limb immobilization in otherwise healthy young men. Eighteen male participants (25.4 ±5.5 y, 81.2 ±11.6 kg) underwent 14 d of unilateral knee-brace immobilization with dietary provision and following four-weeks of training to standardise acute training history. Participant phenotype was characterized before and after 14 days of immobilization, and muscle biopsies were obtained from the vastus lateralis at baseline (pre-immobilization) and at 3 and 14 d of immobilization for analysis by SWATH-MS and subsequent gene-set enrichment analysis (GSEA). Immobilization reduced vastus group cross sectional area (-9.6 ±4.6%, P <0.0001), immobilized leg lean mass (-3.3 ±3.9%, P = 0.002), unilateral 3-repetition maximum leg press (-15.6 ±9.2%, P <0.0001), and maximal oxygen uptake (-2.9 ±5.2%, P = 0.044). SWATH analyses consistently identified 2281 proteins. Compared to baseline, two and 99 proteins were differentially expressed (FDR <0.05) after 3 and 14 d of immobilization, respectively. After 14 d of immobilization, 322 biological processes were different to baseline (FDR <0.05, P <0.001). Most (77%) biological processes were positively enriched and characterized by cellular stress, targeted proteolysis, and protein-DNA complex modifications. In contrast, mitochondrial organization and energy metabolism were negatively enriched processes. This study is the first to use data independent proteomics and GSEA to show that unilateral lower limb immobilization evokes mitochondrial dysfunction, cellular stress, and proteolysis. Through GSEA and network mapping, we identify 27 hub proteins as potential protein/gene candidates for further exploration.
由于关节固定导致的骨骼肌失用会引起肌肉萎缩，这主要归因于人类蛋白质合成的减少。然而，尚无研究使用 SWATH 蛋白质组学方法评估肢体固定对骨骼肌蛋白质组的影响。本研究采用 SWATH 蛋白质组学方法，在健康年轻男性中，描述了单侧下肢固定 3 天和 14 天后个体肌肉蛋白丰度的变化以及相应的基因集。18 名男性参与者（25.4 ±5.5 岁，81.2 ±11.6kg）接受了 14 天的单侧膝部支具固定，并在四周的训练后进行饮食供应，以标准化急性训练史。在 14 天的固定前后，对参与者的表型进行了特征描述，并从股外侧肌获得肌肉活检，在基线（固定前）和固定 3 天和 14 天进行 SWATH-MS 分析和随后的基因集富集分析（GSEA）。固定导致股外侧肌横截面积减少（-9.6 ±4.6%，P <0.0001），固定腿瘦体重减少（-3.3 ±3.9%，P = 0.002），单侧 3 次重复最大腿按压减少（-15.6 ±9.2%，P <0.0001），最大摄氧量减少（-2.9 ±5.2%，P = 0.044）。SWATH 分析一致鉴定出 2281 种蛋白质。与基线相比，固定 3 天和 14 天后分别有 2 和 99 种蛋白质表达差异（FDR <0.05）。固定 14 天后，有 322 种生物学过程与基线不同（FDR <0.05，P <0.001）。大多数（77%）生物学过程呈阳性富集，其特征是细胞应激、靶向蛋白水解和蛋白质-DNA 复合物修饰。相比之下，线粒体组织和能量代谢是负富集的过程。本研究首次使用非依赖性蛋白质组学和 GSEA 表明，单侧下肢固定会引起线粒体功能障碍、细胞应激和蛋白水解。通过 GSEA 和网络映射，我们确定了 27 个枢纽蛋白作为进一步探索的潜在蛋白质/基因候选物。
