Therapeutic potential for AAV/micro-dystrophin transfer to cardiopulmonary tissue

 描述(申请人提供)：Duchenne和Becker肌营养不良症(DMD/BMD)是由dystrophin基因突变引起的X连锁隐性遗传病。DMD是儿童中最常见的致命性遗传性疾病之一，但找到治疗方法仍然是一个难以实现的目标。使用手术、皮质类固醇、呼吸支持和心脏药物的改进的治疗方法正在导致寿命的延长。虽然大多数患者以前死于由于横隔肌和肋间肌肉无力而导致的呼吸衰竭，但已经观察到越来越多的老年患者死于呼吸或心力衰竭。然而，大多数DMD/BMD的治疗策略都集中在四肢肌肉上，尽管有证据表明骨骼肌抢救会加剧心功能障碍。我们的实验室已经证明，腺相关病毒(AAV)载体可以有效地靶向DMD小鼠(MDX)和犬的骨骼肌和心肌，全身注射微肌营养不良素盒可以阻止MDX小鼠的进行性营养不良改变，并显著改善MDX小鼠的横隔膜和心功能。虽然功能挽救令人印象深刻，但仍不完整，最近的研究提出了多种方法来改善微肌营养不良蛋白的功能和肌肉特异性表达。由于MDX小鼠的表型温和，测试和比较这些修饰的微肌营养不良蛋白变得复杂，因此我们建议使用受影响更严重的mdx4cv/DBA-2突变体，该突变体表现出广泛的心肺纤维化和更进步的病理。这些盒将包括新的微肌营养不良蛋白cDNA和新的基因调节盒，这些基因调节盒在系统AAV介导的成年动物基因转移后，针对呼吸和心肌的表达和功能进行了优化。我们还将在旨在防止免疫介导的肌营养不良蛋白表达丢失的策略的背景下整合这些传递系统。其中包括一种新的反向疫苗方案，旨在诱导耐受性和瞬时免疫抑制。这些方法加在一起，可能会显著影响治疗DMD患者呼吸和心肌的能力。这项工作对其他涉及心肺功能障碍的疾病的基因治疗也具有广泛的意义。

 DESCRIPTION (provided by applicant): Duchenne and Becker muscular dystrophies (DMD/BMD) are X-linked recessive genetic disorders caused by mutations in the dystrophin gene. DMD is among the most common lethal inherited disorder of children, but finding a cure remains an elusive goal. Improved treatment approaches using surgery, corticosteroids, respiratory support and heart medication are leading to increases in lifespan. While most patients previously died of respiratory failure due to weakness of the diaphragm and intercostal muscles, a shift has been observed to an increasingly older patient population dying of respiratory or heart failure. Nonetheless, most treatment strategies for DMD/BMD are focused on limb muscles, despite evidence that skeletal muscle rescue can exacerbate cardiac dysfunction. Our lab has shown that adeno-associated viral (AAV) vectors can efficiently target both skeletal and cardiac muscles in mouse (mdx) and canine models for DMD, and that systemic AAV delivery of micro-dystrophin cassettes can halt progressive dystrophic changes and significantly improve diaphragm and cardiac function in mdx mice. Functional rescue, while impressive, is incomplete and recent studies suggest multiple ways to improve the functionality and muscle-specific expression of micro-dystrophin. Testing and comparing these modified micro-dystrophins is complicated by the mildness of the mdx mouse phenotype, so we propose to use a more severely affected mdx4cv/Dba-2 mutant that displays extensive cardiorespiratory fibrosis and a more progressive pathology. These cassettes will comprise both new microdystrophin cDNAs and new gene regulatory cassettes optimized for expression and function in respiratory and cardiac muscle following systemic AAV-mediated gene transfer to adult animals. We will also integrate these delivery systems in the context of strategies designed to prevent immune-mediated loss of dystrophin expression. These include a novel reverse vaccine protocol designed to induce tolerance, and transient immune suppression. Together these approaches could significantly impact the ability to treat respiratory and cardiac muscles of DMD patients. This work also has broad implications for gene therapy of other disorders involving cardiopulmonary dysfunction.