BACKGROUND Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are characterized by muscle wasting leading to loss of ambulation in the first or third decade, respectively. In DMD, the lack of dystrophin hampers connections between intracellular cytoskeleton and cell membrane leading to repeated cycles of necrosis and regeneration associated with inflammation and loss of muscle ordered structure. BMD has a similar muscle phenotype but milder. Here, we address the question whether proteins at variance in BMD compared with DMD contribute to the milder phenotype in BMD, thus identifying a specific signature to be targeted for DMD treatment. METHODS Proteins extracted from skeletal muscle from DMD/BMD patients and young healthy subjects were either reduced and solubilized prior two-dimensional difference in gel electrophoresis/mass spectrometry differential analysis or tryptic digested prior label-free liquid chromatography with tandem mass spectrometry. Statistical analyses of proteins and peptides were performed by DeCyder and Perseus software and protein validation and verification by immunoblotting. RESULTS Proteomic results indicate minor changes in the extracellular matrix (ECM) protein composition in BMD muscles with retention of mechanotransduction signalling, reduced changes in cytoskeletal and contractile proteins. Conversely, in DMD patients, increased levels of several ECM cytoskeletal and contractile proteins were observed whereas some proteins of fast fibres and of Z-disc decreased. Detyrosinated alpha-tubulin was unchanged in BMD and increased in DMD although neuronal nitric oxide synthase was unchanged in BMD and greatly reduced in DMD. Metabolically, the tissue is characterized by a decrement of anaerobic metabolism both in DMD and BMD compared with controls, with increased levels of the glycogen metabolic pathway in BMD. Oxidative metabolism is severely compromised in DMD with impairment of malate shuttle; conversely, it is active in BMD supporting the tricarboxylic acid cycle and respiratory chain. Adipogenesis characterizes DMD, whereas proteins involved in fatty acids beta-oxidation are increased in BMD. Proteins involved in protein/amino acid metabolism, cell development, calcium handling, endoplasmic reticulum/sarcoplasmic reticulum stress response, and inflammation/immune response were increased in DMD. Both disorders are characterized by the impairment of N-linked protein glycosylation in the endoplasmic reticulum. Authophagy was decreased in DMD whereas it was retained in BMD. CONCLUSIONS The mechanosensing and metabolic disruption are central nodes of DMD/BMD phenotypes. The ECM proteome composition and the metabolic rewiring in BMD lead to preservation of energy levels supporting autophagy and cell renewal, thus promoting the retention of muscle function. Conversely, DMD patients are characterized by extracellular and cytoskeletal protein dysregulation and by metabolic restriction at the level of α-ketoglutarate leading to shortage of glutamate-derived molecules that over time triggers lipogenesis and lipotoxicity.

中文翻译：

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比较蛋白质组学分析的杜兴氏肌营养不良症和贝克尔肌营养不良症的肌肉：变化，以保持贝克尔肌营养不良症患者的肌肉功能。

背景技术杜兴氏肌营养不良症（DMD）和贝克尔肌营养不良症（BMD）的特征在于，在第一个或第三个十年中，肌肉萎缩导致行走能力丧失。在DMD中，肌营养不良蛋白的缺乏阻碍了细胞内细胞骨架与细胞膜之间的连接，导致坏死和再生的反复循环与炎症和肌肉有序结构的丧失有关。BMD具有相似的肌肉表型，但较轻。在这里，我们解决了一个问题，即与DMD相比，BMD中变异的蛋白质是否有助于BMD中较温和的表型，从而确定了针对DMD治疗的特异性标记。方法从DMD / BMD患者和年轻健康受试者的骨骼肌中提取的蛋白质通过凝胶电泳/质谱差异分析或胰蛋白酶消化的先前无标记液相色谱-串联质谱法进行还原和溶解，以解决先前的二维差异。通过DeCyder和Perseus软件进行蛋白质和多肽的统计分析，并通过免疫印迹进行蛋白质验证和验证。结果蛋白质组学结果表明BMD肌肉中细胞外基质（ECM）蛋白质组成发生微小变化，并保留了机械转导信号，减少了细胞骨架和收缩蛋白的变化。相反，在DMD患者中，观察到几种ECM细胞骨架和收缩蛋白的水平增加，而快纤维和Z盘的某些蛋白下降。尽管神经元型一氧化氮合酶在BMD中不变并且在DMD中大大降低，但BMD中的去酪氨酸化的α-微管蛋白没有变化，而DMD中的增加。代谢上，该组织的特征是与对照组相比，DMD和BMD中的无氧代谢减少，而BMD中糖原代谢途径的水平增加。DMD中氧化代谢严重受损，苹果酸穿梭受损；相反，它在支持三羧酸循环和呼吸链的BMD中具有活性。脂肪形成是DMD的特征，而参与脂肪酸β-氧化的蛋白质在BMD中增加。参与蛋白质/氨基酸代谢，细胞发育，在DMD中，钙处理，内质网/肌浆网应激反应和炎症/免疫反应增加。两种疾病的特征是在内质网中N-连接蛋白糖基化的损伤。DMD中自噬减少，而BMD中保留。结论机械传感和代谢破坏是DMD / BMD表型的中心节点。BMD中的ECM蛋白质组组成和代谢重新连接导致能量水平得以维持，从而支持自噬和细胞更新，从而促进了肌肉功能的保持。反过来，