Targeted enzyme delivery systems treatment niemann-pick

描述（由申请方提供）：A型和B型尼曼-匹克病（NPD）是一种慢性溶酶体贮积症（LSD），由于酸性鞘磷脂酶（ASM）遗传缺陷，导致鞘磷脂和胆固醇异常蓄积。储存在网状内皮系统（RES;鞘磷脂清除剂）和血管内皮细胞（EC; ASM的主要来源）中会导致肝脾肿大、血管张力障碍、血栓形成、动脉粥样硬化和肺部炎症。因此，NPD导致患者的高发病率和过早死亡率。NPD的酶替代疗法（ERT）依赖于识别ASM糖残基并诱导网格蛋白介导的摄取的受体。重组ASM的次优糖基化和NPD细胞中网格蛋白依赖性内吞作用的改变限制了酶的递送。这证明了替代策略的设计是合理的，但由于这种孤儿病的发病率低，新型NPD疗法的开发受到阻碍。我们假设有效的ERT需要绕过糖基化和网格蛋白途径的方法，并提出了一种替代策略：靶向细胞间粘附分子（ICAM）-1，一种在不同细胞类型（主要是EC和RES）上表达的糖蛋白，上调并在功能上参与NPD病理。我们发现原型ICAM-1靶向纳米载体（涂覆有抗ICAM和ASM的聚苯乙烯珠）通过CAM介导的内吞作用（一种不受NPD影响的非经典途径）被细胞内化，并增强小鼠中的ASM靶向和细胞中的溶酶体递送。评估这种策略的治疗效用将需要反复给药，强制用活性化合物取代免疫原性抗体和不可降解的珠粒。我们建议探索ASM交付的抗ICAM单链抗体（scFv）为靶向的生物相容性PLGA纳米载体。我们假设该系统将：a）将ASM递送至NPD器官和细胞; B）将ASM寻址至溶酶体;以及c）恢复ASM活性。我们将在以下目的中测试这些假设：1-表征ICAM-1靶向的ASM的靶向; 2-定义ICAM-1靶向的ASM的溶酶体递送;和3-在细胞和动物模型中评估由ICAM-1靶向系统递送的ASM活性的恢复。本研究将提供一种生物相容性系统，适用于ICAM-1靶向NPD ERT的安全性和治疗效用的未来研究。该策略的临床获益可扩展至其他LSD。

DESCRIPTION (provided by applicant): Type A and B Niemann-Pick disease (NPD) is a chronic lysosomal storage disorder (LSD) due to a genetic deficiency of acid sphingomyelinase (ASM), which causes aberrant accumulation of sphingomyelin and cholesterol. Storage in the reticulo-endothelial system (RES; sphingomyelin scavengers) and vascular endothelial cells (ECs; a major ASM source) causes hepatosplenomegaly, vascular dystonia, thrombosis, atherosclerosis, and pulmonary inflammation. As a consequence, NPD results in high morbidity and premature mortality in patients. Enzyme replacement therapy (ERT) for NPD depends on receptors that recognize ASM sugar residues and induce clathrin-mediated uptake. Suboptimal glycosylation of recombinant ASM and altered clathrin-dependent endocytosis in NPD cells limit enzyme delivery. This justifies the design of alternative strategies, yet development of novel NPD therapies is hampered due to low incidence of this orphan disease. We hypothesize that effective ERT requires means bypassing glycosylation and clathrin pathways and propose an alternative strategy: targeting Intercellular Adhesion Molecule (ICAM) -1, a glycoprotein expressed on diverse cell types (predominantly ECs and RES), up-regulated and functionally involved in NPD pathology. We showed that prototype ICAM-1-targeted nanocarriers (polystyrene beads coated with anti-ICAM and ASM) are internalized by cells via CAM-mediated endocytosis (a non-classical pathway that is not affected in NPD) and enhance ASM targeting in mice and lysosomal delivery in cells. Evaluation of the therapeutic utility of this strategy will require recurrent administrations, compelling substitution of immunogenic antibody and non-degradable beads by viable compounds. We propose to explore ASM delivery by biocompatible PLGA nanocarriers targeted by anti-ICAM single-chain Fv (scFv). We hypothesize that this system will: a) deliver ASM to NPD organs and cells; b) address ASM to lysosomes; and c) restore ASM activity. We will test these hypotheses in the following Aims: 1-Characterize targeting of ICAM-1-addressed ASM; 2-Define lysosomal delivery of ICAM-1-targeted ASM; and 3-Evaluate the recovery of ASM activity delivered by ICAM-1-targeted system, in both cells and animal models. This study will provide a biocompatible system suitable for future studies on the safety and therapeutic utility of ICAM-1-targeted NPD ERT. The clinical benefits of this strategy may be extended to other LSDs.