Glycosylation-independent enzyme therapy of the brain in Sanfilippo B syndrome

Sanfilippo B 综合征大脑的糖基化非依赖性酶疗法

• 批准号: 8554382
• 负责人: PATRICIA I DICKSON
• 金额: $ 18.4万
• 依托单位: LUNDQUIST INSTITUTE FOR BIOMEDICAL INNOVATION AT HARBOR-UCLA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-30 至 2015-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8554382
• 关键词: 4 year old; Acids; Adult; Affect; Alpha-glucosidase; Amino Acids; Animals; Antibodies; Binding; Biochemical; Birth; Brain; Canis familiaris; Cells; Cerebral Ventricles; Cerebrospinal Fluid; Cessation of life; Characteristics; Child; Chimeric Proteins; Chinese Hamster Ovary Cell; Clinical; Clinical Trials; Cognitive; Data; Development; Disease; Dose; Ensure; Enzymes; Evaluation; Family; Fibroblasts; Frequencies; Genetic; Glycogen storage disease type II; Glycosaminoglycans; Half-Life; Healthcare; Heparitin Sulfate; Human; Hydrolase; IGF Type 2 Receptor; Impairment; Injection of therapeutic agent; Insulin-Like Growth Factor II; Intervention; Intrathecal Space; Intraventricular; Intraventricular Injections; Investigation; Isotonic Exercise; L-Iduronidase; Lead; Life; Ligands; Lysosomal Storage Diseases; Lysosomes; Mammalian Cell; Mannose; Marketing; Microscopic; Morbidity - disease rate; Mucopolysaccharidoses; Mucopolysaccharidosis I; Mucopolysaccharidosis III; Mus; N acetylglucosaminidase; Neurologic; Pathologic; Pathway interactions; Patients; Penetration; Peptide Fragments; Peptides; Phosphorylation; Plants; Problem behavior; Production; Recombinants; Research; Safety; Serum; Site; Syndrome; Testing; Therapeutic; Time; Tissues; Work; Yeasts; alpha-n-acetylglucosaminidase; base; brain tissue; clinically relevant; cost; early childhood; enzyme replacement therapy; enzyme therapy; glycosylation; human IGF2R protein; improved; in vivo; mannose 6 phosphate; mortality; nervous system disorder; novel therapeutics; polypeptide; polysulfated glycosaminoglycan; receptor; scavenger receptor; therapeutic enzyme; trafficking; uptake

DESCRIPTION (provided by applicant): The genetic lysosomal storage disease mucopolysaccharidosis IIIB (MPS IIIB; also called Sanfilippo B syndrome) causes progressive intellectual impairment and behavioral problems beginning in early childhood, culminating in neurological devastation and death, usually by the third decade of life. Enzyme replacement therapy (ERT) has been successfully developed and clinically deployed for other mucopolysaccharidoses, notably MPS I, II, and VI. MPS IIIB is due to deficiency of a soluble lysosomal hydrolase as well, and theoretically should be treatable with ERT. However, the barrier to developing ERTF for MPS IIIB is the fact that the enzyme that is deficient in MPS IIIB (?-N-acetylglucosaminidase, or NAGLU) naturally has sufficient mannose 6-phosphate moieties to enable efficient cellular uptake via the mannose 6-phosphate receptor pathway, but recombinantly-produced NAGLU enters cells inefficiently because it contains little or no mannose 6-phosphorylation. To overcome this hurdle, we developed a fusion protein of insulin-like growth factor 2 (IGF2) and NAGLU (rhNAGLU-IGF2). IGF2 is a natural ligand of the mannose 6-phosphate receptor (a scavenger receptor that is also called IGF2 receptor), and thus provides a way for NAGLU to exploit this receptor for cellular uptake and lysosomal targeting in the absence of mannose 6-phosphate residues. We propose that the IGF2 peptide fused to NAGLU will increase the therapeutic potential of NAGLU by enabling the enzyme to efficiently enter cells and traffic to the lysosomes. To develop this further, we propose preclinicl studies to determine whether intraventricular rhNAGLU-IGF2 safely and effectively reduces lysosomal storage in MPS IIIB (Naglu-/-) mice (Aim 1) and to determine the brain distribution of intraventricular rhNAGLU-IGF2 (Aim 2). To achieve these objectives, we will deliver rhNAGLU, the rhNAGLU-IGF2 fusion, or vehicle control intraventricularly to MPS IIIB mice. We will then perform detailed pathologic, immunohistochemical, confocal microscopic, and biochemical functional analyses, as well as distribution and penetration studies as a function of dose and time following delivery. Our preliminary data show that rhNAGLU- IGF2 enters MPS IIIB fibroblasts far more efficiency than rhNAGLU. The clinical relevance of this work is supported by the following: a) recombinant ERT is approved and marketed for several other MPS disorders and lysosomal storage diseases; b) clinical trials of intrathecally-delivered enzyme replacement therapy are ongoing for three other MPS types, but not MPS IIIB; and c) a clinical trial of an IGF2-tagged lysosomal enzyme (acid alpha-glucosidase) has recently begun. All these not only establish precedence for translational relevance, but will guide development of our proposed application with rhNAGLU-IGF2. Thus, we are optimistic that rhNAGLU-IGF2 may be successfully developed to treat a devastating, fatal disease for which no treatment exists, and furthermore, that this approach may ultimately be adapted to other genetically-based lysosomal storage diseases as well.

描述（由申请人提供）：遗传性溶酶体贮积症粘多糖贮积症 IIIB（MPS IIIB；也称为 Sanfilippo B 综合征）会导致儿童早期开始的进行性智力障碍和行为问题，最终导致神经系统破坏和死亡，通常在生命的第三个十年。酶替代疗法 (ERT) 已成功开发并临床应用于其他粘多糖病，特别是 MPS I、II 和 VI。 MPS IIIB 也是由于可溶性溶酶体水解酶缺乏所致，理论上应该可以用 ERT 治疗。然而，开发用于 MPS IIIB 的 ERTF 的障碍是 MPS IIIB 中缺乏的酶（β-N-乙酰氨基葡萄糖苷酶，或 NAGLU）天然具有足够的甘露糖 6-磷酸部分，能够通过甘露糖 6- 实现有效的细胞摄取。磷酸受体途径，但重组产生的 NAGLU 进入细胞效率低下，因为它含有很少或不含甘露糖 6-磷酸化。为了克服这一障碍，我们开发了胰岛素样生长因子 2 (IGF2) 和 NAGLU (rhNAGLU-IGF2) 的融合蛋白。 IGF2 是 6-磷酸甘露糖受体（一种清道夫受体，也称为 IGF2 受体）的天然配体，因此为 NAGLU 在没有 6-磷酸甘露糖残基的情况下利用该受体进行细胞摄取和溶酶体靶向提供了一种方法。我们认为，与 NAGLU 融合的 IGF2 肽将使酶能够有效地进入细胞并转运至溶酶体，从而增加 NAGLU 的治疗潜力。为了进一步发展这一点，我们建议进行临床前研究，以确定脑室内 rhNAGLU-IGF2 是否安全有效地减少 MPS IIIB (Naglu-/-) 小鼠的溶酶体储存（目标 1），并确定脑室内 rhNAGLU-IGF2 的大脑分布（目标 2） ）。为了实现这些目标，我们将向 MPS IIIB 小鼠脑室内注射 rhNAGLU、rhNAGLU-IGF2 融合物或载体对照。然后，我们将进行详细的病理学、免疫组织化学、共聚焦显微镜和生化功能分析，以及作为分娩后剂量和时间函数的分布和渗透研究。我们的初步数据表明，rhNAGLU-IGF2 进入 MPS IIIB 成纤维细胞的效率远高于 rhNAGLU。这项工作的临床相关性得到以下支持：a) 重组 ERT 已被批准并上市用于其他几种 MPS 疾病和溶酶体贮积病； b) 鞘内递送酶替代疗法的临床试验正在进行中，用于其他三种 MPS 类型，但不包括 MPS IIIB； c) IGF2 标记的溶酶体酶（酸性 α-葡萄糖苷酶）的临床试验最近已开始。所有这些不仅确立了翻译相关性的优先级，而且将指导我们提出的 rhNAGLU-IGF2 应用的开发。因此，我们乐观地认为，rhNAGLU-IGF2可能会成功开发用于治疗一种尚无治疗方法的毁灭性致命疾病，而且这种方法最终也可能适用于其他基于遗传的溶酶体贮积病。