Chaubourt E, Voisin V, Fossier P, Baux G, Israël M, de La Porte S
Laboratoire de neurobiologie cellulaire et moléculaire, CNRS UPR 9040, Gif-sur-Yvette, France.
C R Acad Sci III. 2000 Aug;323(8):735-40. doi: 10.1016/s0764-4469(00)01219-1.
Duchenne muscular dystrophy (DMD), a severe X-linked recessive disorder that results in progressive muscle degeneration, is due to a lack of dystrophin, a membrane cytoskeletal protein. An approach to the search for a treatment is to compensate for dystrophin loss by utrophin, another cytoskeletal protein. During development, in normal as in dystrophic embryos, utrophin is found at the membrane surface of immature skeletal fibres and is progressively replaced by dystrophin. Thus, it is possible to consider utrophin as a 'foetal homologue' of dystrophin. In a previous work, we studied the effect of L-arginine, the substrate of nitric oxide synthetase (NOS), on utrophin expression at the muscle membrane. Using a novel antibody, we confirm here that the immunocytochemical staining was indeed due to an increase in utrophin at the sarcolemma. The result is observed not only on mdx (an animal model of DMD) myotubes in culture but also in mdx mice treated with L-arginine. In addition, we show here the utrophin increase in muscle extracts of mdx mice treated with L-arginine, after electrophoretic separation and western-blotting using this novel antibody, and thus extending the electrophoretic results previously obtained on myotube cultures to muscles of treated mice.
杜兴氏肌营养不良症（DMD）是一种严重的X连锁隐性疾病，会导致进行性肌肉退化，其病因是缺乏肌营养不良蛋白，一种膜细胞骨架蛋白。寻找治疗方法的一种途径是通过另一种细胞骨架蛋白——抗肌萎缩蛋白聚糖来弥补肌营养不良蛋白的缺失。在发育过程中，无论是正常胚胎还是患肌营养不良症的胚胎，抗肌萎缩蛋白聚糖都存在于未成熟骨骼肌纤维的膜表面，并逐渐被肌营养不良蛋白取代。因此，可以将抗肌萎缩蛋白聚糖视为肌营养不良蛋白的“胎儿同源物”。在之前的一项研究中，我们研究了一氧化氮合酶（NOS）的底物L-精氨酸对肌膜上抗肌萎缩蛋白聚糖表达的影响。在这里，我们使用一种新型抗体证实，免疫细胞化学染色确实是由于肌膜上抗肌萎缩蛋白聚糖的增加所致。不仅在培养的mdx（DMD动物模型）肌管上观察到了这一结果，在用L-精氨酸处理的mdx小鼠中也观察到了这一结果。此外，我们在这里展示了在用L-精氨酸处理的mdx小鼠的肌肉提取物中，使用这种新型抗体进行电泳分离和蛋白质印迹后抗肌萎缩蛋白聚糖的增加，从而将先前在肌管培养物上获得的电泳结果扩展到了经处理小鼠的肌肉。
