Day Neuromuscular Research Laboratory, Massachusetts General Hospital, Charlestown, MA.
Ann Neurol. 2010 Mar;67(3):384-93. doi: 10.1002/ana.21926.
The dose-response effects of dysferlin transgenesis were analyzed to determine if the dysferlin-deficient myopathies are good candidates for gene replacement therapy.
We have generated 3 lines of transgenic mice, expressing low, mid, and high levels of full-length human dysferlin from a muscle-specific promoter. Transgenic skeletal muscle was analyzed and scored for morphological and functional deficits.
Overexpression of dysferlin in mice resulted in a striking phenotype of kyphosis, irregular gait, and reduced muscle mass and strength. Moreover, protein dosage correlated with phenotype severity. In contrast to dysferlin-null skeletal muscle, no evidence of sarcolemmal impairment was revealed. Rather, increased levels of Ca(2+)-regulated, dysferlin-binding proteins and endoplasmic reticulum stress chaperone proteins were observed in muscle lysates from transgenic mice as compared with controls.
Expression levels of dysferlin are important for appropriate function without deleterious or cytotoxic effects. As a corollary, we propose that future endeavors in gene replacement for correction of dysferlinopathy should be tailored to take account of this.
分析肌营养不良蛋白转导的剂量反应效应，以确定肌营养不良蛋白缺乏型肌病是否适合基因替代治疗。
我们已经生成了 3 条转基因鼠系，利用肌特异性启动子低、中、高表达全长人肌营养不良蛋白。分析和评估转基因骨骼肌的形态和功能缺陷。
在小鼠中过度表达肌营养不良蛋白会导致明显的脊柱后凸、步态不规则以及肌肉质量和力量减少。此外，蛋白剂量与表型严重程度相关。与肌营养不良蛋白缺失的骨骼肌不同，未发现肌膜损伤的证据。相反，与对照组相比，在转基因鼠的肌肉裂解物中观察到钙调节的肌营养不良蛋白结合蛋白和内质网应激伴侣蛋白水平升高。
肌营养不良蛋白的表达水平对于适当的功能很重要，而没有有害或细胞毒性作用。因此，我们提出，未来纠正肌营养不良蛋白病的基因替代治疗应考虑到这一点。
