Gene therapy for alpha-mannosidosis

描述（由申请人提供）：多年来，血脑屏障一直被认为是溶酶体贮积病全身治疗到达中枢神经系统的主要障碍。然而，最近的数据表明，高水平的血清β -葡糖醛酸酶可以改变成人粘多糖病VII小鼠的中枢神经系统病变和行为异常。但问题仍然存在，这一观察结果是否仅限于小鼠和粘多糖病VII，或者它是否适用于大型动物作为儿童和其他溶酶体贮积病的模型？本奖助金提案旨在回答这些问题。我们发现，在新生儿静脉注射逆转录病毒基因治疗后，血清α - l -伊杜糖醛酸酶和β -葡萄糖醛酸酶水平持续升高的粘多糖病I型和VII型犬的中枢神经系统神经病理病变有所改善。然而，由于粘多糖病犬缺乏中枢神经系统病变的临床症状，因此无法评估大型动物神经功能的改善。这项拨款申请建议使用体细胞（基于肝脏）基因疗法测试患有α -甘露甘露病的猫的血清活性水平，这些水平与穿越血脑屏障相关。α -甘露甘露病猫有明显的、有充分记录的神经系统疾病症状，如果不治疗，可在6个月大时死亡，并有详细描述的神经病理病变。α -甘露甘露病猫也被证明对骨髓移植和直接脑部注射病毒载体有反应，因此高血清酶活性是否成功将是明确的。因此，我们建议确定高恒定的血清α -甘露糖苷酶活性是否会穿过血脑屏障，从而消除临床和神经病理疾病。在提出基因治疗临床试验之前，这是一个重要的原理证明，可以在儿童中发现的60%溶酶体积存病伴有中枢神经系统病变的任何一种疾病中产生高血清酶活性。

DESCRIPTION (provided by applicant): For many years, the blood brain barrier has been considered a major obstacle to systemic therapy to reach the central nervous system for lysosomal storage diseases. However, recent data have indicated that high serum levels of beta-glucuronidase can alter the central nervous system lesions and behavioral abnormalities in adult mucopolysaccharidosis VII mice. But the question remains, is this observation limited to mice and to mucopolysaccharidosis VII or will it be true for large animals as models for children and for other lysosomal storage diseases? This grant proposal is designed to answer these questions. We have shown improvement in central nervous system neuropathological lesions in mucopolysaccharidosis I and VII dogs with constant high serum levels of alpha-L-iduronidase and beta-glucuronidase, respectively, following neonatal, intravenous retroviral gene therapy. However, because the mucopolysaccharidosis dogs lack clinical signs of the central nervous system lesions, improvement in neurological function in the large animals could not be evaluated. This grant application proposes to test the levels of serum activity associated with transit across the blood brain barrier using somatic (liver-based) gene therapy in cats with alpha-mannosidosis. Alpha-mannosidosis cats have significant, well-documented neurological signs of disease, with death by six months of age if untreated, and well-described neuropathological lesions. Alpha-mannosidosis cats have also been shown to respond to bone marrow transplantation and direct brain injection of a viral vector so it will be clear if high serum enzyme activity is successful. Thus, we propose to determine if high constant serum alpha- mannosidase activity will cross the blood brain barrier and abrogate the clinical and neuropathological disease. This is an important proof of principle before proposing gene therapy clinical trials to produce high serum enzyme activity in any of the 60% of lysosomal storage diseases with central nervous system lesions found in children. PUBLIC HEALTH RELEVANCE: This grant proposes to treat young cats with the naturally occurring genetic storage disease, alpha-mannosidosis, by using gene therapy. The goal is to produce enough normal therapeutic enzyme in the liver to allow it to cross the blood brain barrier and prevent or reverse the disease in the brain.