Iduronidase Replacement Therapy of the Brain in Hurler's Syndrome

描述(申请人提供)：摘要有40多种溶酶体储存障碍，这些疾病大多对中枢神经系统(CNS)有不利影响。目前主要的治疗方法是酶替代疗法(ERT)。然而，ERT对大脑无效，因为这些酶不会穿过大脑毛细血管壁，而毛细血管壁在体内形成血脑屏障(BBB)。如果不对中枢神经系统进行治疗，这些年轻患者注定会出现进行性神经变性和死亡。在这些疾病的未来治疗中，限制因素是酶通过血脑屏障的运输。直接向脑内注射血脑屏障是无效的，因为只有一小部分大脑通过经颅输送系统进行治疗。相反，几乎所有的脑细胞都可以通过血管输送系统进行治疗，这种系统可以使酶在静脉注射后穿过血脑屏障。一种新的BBB递送大分子如酶的方法是分子特洛伊木马技术。利用基因工程技术生产双功能融合蛋白，将缺失的重组酶与BBB分子木马融合。后者是一种基因工程蛋白，能够通过内源性BBB多肽转运系统上的受体介导的跨细胞作用穿过人的BBB。临床前研究表明，一种分子量为100,000道尔顿的大酶可以通过跨血脑屏障的运输传递到大脑，然后连接到血脑屏障受体特异性特洛伊木马上。目前的工作将产生编码人类艾杜糖醛酸酶的新型融合基因和基因工程分子特洛伊木马，这将使相应的融合蛋白AGT-181的生产成为可能。这种新的融合蛋白将成为治疗赫勒综合征大脑的新方法。这项工作的目的是制造生物反应器产生的AGT-181，执行这种新药的GLP药理-毒理学，检查AGT-181的组织交叉反应，并准备并向FDA提交用于治疗Hurler综合征脑的IND。 公共卫生相关性：项目叙述溶酶体储存障碍是严重的先天性新陈代谢错误，约75%的~40种溶酶体储存障碍影响大脑。主要的治疗方法是酶替代疗法(ERT)。然而，ERT在大脑中是无效的，因为这些酶不能穿过血脑屏障(BBB)。本工作将产生一种新型的重组融合蛋白，它能够(A)结合人的BBB受体以触发转运到大脑中，(B)保持高溶酶体酶活性。这种新药被命名为AGT-181，将成为治疗赫勒综合征大脑的新疗法。

DESCRIPTION (provided by applicant): Abstract There are over 40 lysosomal storage disorders, and most of these diseases affect adversely the central nervous system (CNS). The mainstay of treatment is enzyme replacement therapy (ERT). However, ERT is not effective for the brain, because the enzymes do not cross the brain capillary wall, which forms the blood-brain barrier (BBB) in vivo. Without treatment of the CNS, the young patients are destined to progressive neurodegeneration and death. The limiting factor in the future treatment of these diseases is the transport of the enzyme across the BBB. Bypass of the BBB with direct injection into the brain is not effective, because only a small part of the brain is treated with a trans-cranial delivery system. Conversely, virtually all cells of the brain can be treated with a trans-vascular delivery system that enables the enzyme to cross the BBB following intravenous administration. A new approach to the BBB delivery of large molecules such as enzymes is the molecular Trojan horse technology. A bi-functional fusion protein is produced with genetic engineering, wherein the missing recombinant enzyme is fused to a BBB molecular Trojan horse. The latter is a genetically engineered protein that is able to cross the human BBB by receptor- mediated transcytosis on endogenous BBB peptide transport systems. Pre-clinical studies show that a large enzyme with a molecular weight >100,000 Daltons, can be delivered to brain via transport across the BBB, following attachment to a BBB receptor-specific Trojan horse. The present work will produce a novel fusion gene encoding human iduronidase and a genetically engineered molecular Trojan horse, which will allow the production of the corresponding fusion protein, AGT-181. This new fusion protein will be a new treatment of the brain in Hurler's syndrome. The aims of this work are to manufacture bioreactor-generated AGT-181, perform the GLP pharmacology-toxicology of this new drug, examine the tissue cross reactivity of AGT-181, and to prepare and file an IND to the FDA for the treatment of the brain in Hurler's syndrome. PUBLIC HEALTH RELEVANCE: Project Narrative Lysosomal storage disorders are serious inborn errors of metabolism, and about 75% of the ~40 lysosomal storage disorders affect the brain. The mainstay of treatment is Enzyme Replacement Therapy (ERT). However, ERT is ineffective in the brain, because the enzymes do not cross the blood-brain barrier (BBB). The present work will produce a novel recombinant fusion protein that is able to both (a) bind a human BBB receptor to trigger transport into the brain, and (b) retain high lysosomal enzyme activity. This novel drug, designated AGT-181, will be new treatment for the brain in Hurler's syndrome.