Therapeutic Potent. of e-sarcoglycan in LGMD Type 2D

描述（申请人提供）：该项目的长期目标是设计一种治疗常染色体隐性肢带型肌营养不良症2D型（LGMD-2D）的方法，该疾病是由于染色体畸变引起的。α-肌聚糖与β-，γ-，和δ-肌聚糖形成亚复合物，该亚复合物增加肌营养不良蛋白-糖蛋白复合物（DGC）的总体稳定性。ε-肌聚糖是肌肉特异性α-肌聚糖的普遍表达的同源物，具有43%的同一性和相似的蛋白质结构。在E15检测到α-肌聚糖之前，早在E8.5天就在小鼠胚胎中检测到ε-肌聚糖表达，初步数据显示在肌肉再生期间检测增加，表明ε-肌聚糖是α-肌聚糖的胚胎或发育形式。该项目的重点是探索上调ε-肌聚糖水平治疗LGMD-2D的治疗潜力。第一个目标假设ε-肌聚糖的表达增加将取代DGC内的α-肌聚糖。表征具有针对肌肉的ε-肌聚糖的靶向过表达的转基因小鼠将检验该假设。第二个目的假设ε-肌聚糖表达的增加将补偿异常的α-肌聚糖，以防止肌营养不良症的发作。对过表达ε-肌聚糖的Sgca缺失小鼠的分析将检验这一假设。最终目的假设α-肌聚糖缺乏症中ε-肌聚糖表达的增加和持续将防止进一步的肌肉病理学并修复原发性膜缺损以允许正常的肌肉功能。将成年Sgca缺失小鼠肌内注射rAAV 1 ε-肌聚糖并进行分析。该项目将研究增加ε-肌聚糖水平的功能和生理后果，以预防和治疗α-肌聚糖缺乏症中的肌营养不良症。这些实验的总体结果将开发增加ε-肌聚糖表达以补偿LGMD-2D患者中的ε-肌聚糖的可能性。专注于内源性蛋白质如ε-肌聚糖将绕过任何获得性治疗性免疫反应，并为旨在上调ε-肌聚糖的治疗和药物治疗提供新靶点的平台

DESCRIPTION (provided by applicant): The long-term goal of this project is to design a therapy for autosomal recessive limb-girdle muscular dystrophy type 2D (LGMD-2D), which is due to aberrations in the (-sarcoglycan gene (Sgca), and affects mainly limb and girdle muscles to lead to progressive muscle fiber necrosis and weakness, Alpha-Sarcoglycan interacts with beta-, gamma-, and delta-sarcoglycan to form a subcomplex that increases the overall stability of the dystrophin-glycoprotein complex (DGC). Epsilon-Sarcoglycan is a ubiquitously expressed homologue of the muscle-specific alpha- sarcoglycan, sharing 43% identity and a similar protein structure. Epsilon-Sarcoglycan expression is detected as early as day E8.5 in mouse embryos before the detection of alpha-sarcoglycan at E15, and preliminary data shows increased detection during muscle regeneration suggesting that epsilon-sarcoglycan is embryonic or developmental form of alpha-sarcoglycan. This project focuses on exploring the therapeutic potential of upregulating epsilon-sarcoglycan levels for the treatment of LGMD-2D. The First Aim hypothesizes that increased expression of epsilon-sarcoglycan will replace alpha-sarcoglycan within the DGC. Characterization of transgenic mice with targeted overexpression of epsilon-sarcoglycan to muscle will test this hypothesis. The Second Aim hypothesizes that increased expression of epsilon-sarcoglycan will compensate for an aberrant alpha-sarcoglycan to prevent the onset of muscular dystrophy. Analysis of Sgca-null mice overexpressing epsilon-sarcoglycan will test this hypothesis. The Final Aim hypothesizes that increased and sustained epsilon-sarcoglycan expression in alpha-sarcoglycan deficiency will prevent further muscle pathology and repair the primary membrane defect to allow for normal muscle function. Adult Sgca-null mice will be intramuscularly injected with rAAVl epsilon-sarcoglycan and analyzed. This project will investigate the functional and physiological consequences of increased levels of epsilon-sarcoglycan to prevent and treat muscular dystrophy in alpha-sarcoglycan deficiency. The overall results of these experiments will develop the possibility of increased epsilon-sarcoglycan expression to compensate for (-sarcoglycan in LGMD-2D patients. Focusing on an endogenous protein like epsilon-sarcoglycan will bypass any acquired therapeutic immune response, and provides a platform for new targets for therapy and drug treatments aimed at up-regulating epsilon-sarcoglycan