Novel therapeutics strategies for Duchenne MD

这项建议的总体目标是探索改善肌肉细胞膜维护和修复治疗Duchenne肌营养不良症的治疗潜力。特别是，该提案将检验这些假说：1)糖基转移酶的过表达将稳定mdx肌肉的肌膜，从而防止或延缓肌肉病理；2)过表达deferlin将改善mdx小鼠的肌膜修复，从而预防或延缓肌肉病理。在Duchenne肌营养不良症患者和mdx小鼠中，dystrophin的缺失导致肌膜上的dystroglan减少，肌膜和细胞外之间的连接中断。 矩阵。我们先前已经证明，在野生型肌肉中过表达Large会增加α-肌营养不良聚糖的糖基化和层粘连蛋白结合活性。我们假设，在没有肌营养不良蛋白的情况下，MDX肌肉中α-肌营养不良聚糖的大依赖性高糖基化将维持肌膜上的α-肌营养不良聚糖，从而稳定肌膜及其与细胞外基质的联系。第一个目标将通过病毒介导的MDX肌肉中的Large过表达以及与MDX小鼠杂交的大型转基因小鼠来验证这一假说。在第二个目标中，我们建议增加和 去铁蛋白在MDX肌肉中的持续表达将通过促进膜修复来预防病理。最近，对功能障碍小鼠的研究揭示了一种新的肌肉发病机制，即肌膜的膜修复而不是结构完整性异常。我们对dystrophin/deferlin缺失小鼠的初步数据表明，deferlin可能在减轻MDX肌肉病理中发挥作用，因为在缺乏这两种蛋白的情况下，营养不良的变化更严重。为了验证这一假说，MDX小鼠将接受表达deferlin的腺病毒治疗，或者与deferlin转基因小鼠杂交。因此，这个项目将调查潜在有益的功能和生理后果。 大蛋白或异铁蛋白表达增加。聚焦于内源性蛋白，如大的或功能障碍蛋白，其活性可能被调节，将为新的治疗靶点(可能是药物治疗)提供一个平台，旨在上调大的或功能障碍蛋白的表达和/或活性来治疗Duchenne肌营养不良。

The overall objective of this proposal is to explore the therapeutic potential of improving muscle cell membrane maintenance and repair for the treatment of Duchenne muscular dystrophy. In particular, the proposal will test these hypotheses: 1) Overexpression of the glycosyltransferase, LARGE, will stabilize the sarcolemma in mdx muscle and thus prevent or delay muscle pathology; and 2) Overexpression of dysferlin will improve muscle membrane repair in mdx mice and thus prevent or delay muscle pathology. In Duchenne muscular dystrophy patients and mdx mice, the absence of dystrophin leads to a reduction of dystroglycan at the sarcolemma and disruption in the link between the sarcolemma and the extracellular matrix. We have previously demonstrated that Overexpression of LARGE will increase the glycosylation and laminin binding activity of alpha-dystroglycan in wild type muscle. We hypothesize that LARGE-dependant hyperglycosylation of alpha-dystroglycan in mdx muscle will maintain alpha-dystroglycan at the sarcolemma and thereby stabilize the muscle membrane and its link with extracelluar matrix in the absence of dystrophin. The first aim will test this hypothesis using viral-mediated Overexpression of LARGE in mdx muscle and LARGE transgenic mice crossed with mdx mice. In the second aim we propose that an increased and sustained expression of dysferlin in mdx muscle will prevent pathology by improving membrane repair. Recently, studies on dysferlin-null mice have revealed a new mechanism of muscle pathogenesis where membrane repair, and not structural integrity, of the sarcolemma is abnormal. Our preliminary data on dystrophin/dysferlin-null mice suggests that dysferlin may play a role in diminishing mdx muscle pathology because the dystrophic changes are more severe in the absence of both proteins. To test this hypothesis, mdx mice will be treated with dysferlin-expressing adenovirus or crossed with dysferlin transgenic mice. Therefore, this project will investigate the potentially beneficial functional and physiological consequences of increased expression of LARGE or dysferlin. Focusing on endogenous proteins like LARGE or dysferlin, whose activity could potentially be modulated, will provide a platform for new targets of therapy (possibly pharmacological treatments) aimed at upregulating LARGE or dysferlin expression and/or activity to treat Duchenne muscular dystrophy.