Targeted replacement of defective lysosomal enzymes in the lung and brain

尽管发病率很低，但遗传病给家庭和卫生系统造成的经济负担极高，原因是治疗费用（10万美元/病人年）大多数在缓解这些慢性病方面不理想。这是用于治疗溶酶体贮积症（LSD）的酶替代疗法（Erts）的情况，所述溶酶体贮积症是由于溶酶体酶缺乏引起的普遍遗传缺陷。ERT的成功仅限于影响肝脏、脾脏和肾脏的少数疾病，其中注射的酶通过血液清除机制获得。然而，对于大多数常见的神经学LSD，ERT递送至肺或脑受到缺乏亲和力和酶向组织和组织中的运输的阻碍。一个例子是用于由于酸性鞘磷脂酶（ASM）缺乏而引起的尼曼-皮克病（NPD）的ERT，其中鞘磷脂的溶酶体过量引起强烈的神经障碍（A型表型）并影响肺、肝和脾（B型表型）。我们的目标是制定策略，以改善对疾病部位（肺和脑）的ERT输送。我们建议将ASM靶向细胞间粘附分子-1（ICAM-1），ICAM-1表达于所有器官的内皮细胞和组织实质中的细胞靶点，并在NPD中上调。我们的研究结果表明，经典的内吞相关的囊泡运输从血液到组织和细胞表面的溶酶体是有缺陷的NPD，但非经典的途径诱导的ICAM-1参与多价抗ICAM/聚苯乙烯原型载体是完全活跃的NPD。这些原型增强ASM靶向溶酶体和鞘磷脂减少培养的内皮细胞和小鼠。一部分抗ICAM原型载体被转运通过内皮培养物。我们假设，生物相容性ICAM-1靶向载体可以提供ASM的囊泡转运穿过内皮屏障（不影响渗透性）和内吞作用和溶酶体递送到组织实质细胞中，从而减弱NPD肺和脑表型。我们将在细胞和小鼠模型中测试这一点，使用我们的新的生物相容性PLGA载体，通过其天然配体衍生的肽靶向ICAM-1，目的是评估和优化：1-跨内皮转运的有效性和安全性，2-非内皮递送，和3-NPD表型的影响。这种将治疗剂运输穿过内皮屏障并进入细胞的策略的益处可能超越其他LSD和CNS治疗。

Despite a low incidence, the economical burden of genetic diseases to families and the health system is extremely high, due to the cost of therapies ($100,000/patient-year) mostly suboptimal in alleviating these chronic conditions. This is the case for enzyme replacement therapies (ERTs) for treatment of lysosomal storage disorders (LSDs), prevalent genetic defects due to deficiency of lysosomal enzymes. ERT success is restricted to a few diseases affecting liver, spleen, and kidneys, where injected enzymes gain access via mechanisms of blood clearance. However, ERT delivery to the lungs, or brain for most common neurological LSDs, is hindered by the lack of affinity and transport of the enzymes to and into tissues. An example is ERT for Niemann-Pick disease (NPD) due to acid sphingomyelinase (ASM) deficiency, where lysosomal excess of sphingomyelin causes strong neurological disorder (type A phenotype) and affects lungs, liver and spleen (type B phenotype). Our goal is to develop strategies to improve ERT delivery to disease sites (lungs and brain). We propose to target ASM to intercellular adhesion molecule-1 (ICAM-1) expressed on the endothelium of all organs and cell targets in the parenchyma of tissues, and up-regulated in NPD. Our results indicate that classical endocytosis associated to vesicular transport from the blood to the tissue and the cell surface to lysosomes are defective in NPD, yet the non-classical pathway induced by ICAM-1 engagement by multivalent anti-ICAM/polystyrene prototype carriers is fully active in NPD. These prototypes enhance ASM targeting to lysosomes and sphingomyelin reduction in cultured endothelial cells and mice. A fraction of anti-ICAM prototype carriers are transported across endothelial cultures. We hypothesize that biocompatible ICAM-1- targeted carriers can provide vesicular transport of ASM across endothelial barriers (without affecting permeability) and endocytosis and lysosomal delivery in cells of the tissue parenchyma, attenuating NPD lung and brain phenotype. We will test this in cells and mouse models, using our new biocompatible PLGA carriers targeted to ICAM-1 by a peptide derived from its natural ligand, in Aims to evaluate and optimize: 1-Efficacy and safety of transendothelial transport, 2-Non-endothelial delivery, and 3-Effects in the NPD phenotype. The benefits of this strategy to transport therapeutics across endothelial barriers and into cells may transcend other LSDs and CNS treatments.