Genetic Therapy for CNS Manifestations in MPS I via BBB-targeted Protein Delivery

描述（由申请人提供）： Ⅰ型粘多糖沉积症（MPS I）是一种常见的中枢神经系统溶酶体贮积病，主要由α-L-艾杜糖醛酸酶（IDUA）缺乏引起，目前的治疗方法尚不能治愈。我们已经表明，慢病毒载体（LV）介导的基因传递可以产生持续的超生理IDUA水平的血浆，并可能在治疗中枢神经系统的表现，如果血脑屏障（BBB）可以克服治疗。内源性受体介导的转胞吞系统在BBB形成脑毛细血管内皮上的利用将使得神经治疗剂能够通过循环快速且广泛地递送穿过BBB。提出的工作的总体目标是开发一种新的治疗方法，利用低密度脂蛋白受体家族（LDLRf）介导的转胞吞作用，通过肝脏和/或HSC中LV介导的基因转移将融合蛋白递送穿过BBB，用于治疗MPS I的CNS表现。我们将通过体外和体内评价确定apoE的最佳LDLRf结合结构域，以最有效地进行BBB转运，同时保留融合IDUA的正常催化功能和溶酶体酶转运（特异性目的1）。将在CNS和外周器官中研究蛋白质的空间和时间分布特征，靶向肝脏或HSC衍生的红系细胞作为不同年龄小鼠中组织特异性转基因生产的储库器官（特定目的2）。将在小鼠MPS I模型中进行临床前评价，以通过用于代谢校正的GAG测定、用于CNS正常化的病理学评价和用于改善CNS功能缺陷的行为评估来确定CNS治疗的窗口（具体目标3）。总之，这些研究不仅将导致开发一种用于治疗神经系统疾病的新方法，例如在MPS I中，终身BBB靶向蛋白质递送，而且还提供了受体介导的BBB转运系统随衰老或病理条件下的体内变化的重要知识。 公共卫生相关性： 血脑屏障阻碍了神经治疗剂和诊断剂向中枢神经系统的快速和广泛递送的能力。本申请中描述的研究将为治疗神经系统疾病的新方法打开大门-从MPS I型到主要的公共卫生问题，如中风和阿尔茨海默病。

DESCRIPTION (provided by applicant): Abstract Mucopolysaccharidosis type I (MPS I), resulting from the deficiency of alpha-L- iduronidase (IDUA), is one of the most common lysosomal storage diseases (LSD) affecting the central nervous system (CNS), which cannot be cured by current treatments. We have shown that lentiviral vector (LV)-mediated gene delivery can produce sustained supraphysiological IDUA levels in plasma and may be therapeutic in treating CNS manifestations if the blood-brain barrier (BBB) can be overcome. The utilization of the endogenous receptor-mediated transcytosis system on BBB-forming brain capillary endothelium will enable rapid and wide delivery of neurotherapeutics across the BBB via circulation. The overall goal of the work proposed is to develop a novel therapeutic approach utilizing low-density lipoprotein receptor family (LDLRf)- mediated transcytosis for fusion protein delivery across the BBB via LV-mediated gene transfer in the liver and/or the HSC for the treatment of CNS manifestations in MPS I. We will identify, by in vitro and in vivo evaluation, the optimal LDLRf-binding domain of apoE for most efficient BBB transport while retaining the normal catalytic function and lysosomal enzyme trafficking of fusion IDUA (Specific Aim 1). The spatial and temporal protein distribution profile will be studied in the CNS and peripheral organs, targeting the liver or HSC-derived erythroid cells as depot organ for tissue-specific transgene production in mice with different ages (Specific Aim 2). Preclinical evaluation will be conduced in a murine MPS I model to identify window of CNS treatment by GAG assay for metabolic correction, pathology evaluation for CNS normalization and behavioral assessments for improvement of CNS functional deficits (Specific Aim 3). Taken together, these studies will not only lead to the development of a novel approach for the treatment of neurological diseases, such as in MPS I, with lifelong BBB-targeted protein delivery, but also provide important knowledge of in vivo changes in receptor-mediated BBB transport system with aging or under pathological conditions. PUBLIC HEALTH RELEVANCE: Narrative The blood-brain-barrier has hindered the capability of rapid and wide delivery of neurotherapeutics and diagnostic agents to the central nervous system. The studies described in this application will open the door to novel approaches for the treatment of neurological disorders-from MPS type I to major public health concerns such as stroke and Alzheimer's disease.