利用血脑屏障转运载体在小鼠中实现溶酶体酶的脑内递送和活性。

Brain delivery and activity of a lysosomal enzyme using a blood-brain barrier transport vehicle in mice.

机构信息

Denali Therapeutics Inc., 161 Oyster Point Blvd., South San Francisco, CA 94080, USA.

Mass Spectrometry Research Center, Vanderbilt University, 9160 MRB III, 465 21 Avenue South, Nashville, TN 37240, USA.

出版信息

Sci Transl Med. 2020 May 27;12(545). doi: 10.1126/scitranslmed.aay1163.

Abstract

Most lysosomal storage diseases (LSDs) involve progressive central nervous system (CNS) impairment, resulting from deficiency of a lysosomal enzyme. Treatment of neuronopathic LSDs remains a considerable challenge, as approved intravenously administered enzyme therapies are ineffective in modifying CNS disease because they do not effectively cross the blood-brain barrier (BBB). We describe a therapeutic platform for increasing the brain exposure of enzyme replacement therapies. The enzyme transport vehicle (ETV) is a lysosomal enzyme fused to an Fc domain that has been engineered to bind to the transferrin receptor, which facilitates receptor-mediated transcytosis across the BBB. We demonstrate that ETV fusions containing iduronate 2-sulfatase (ETV:IDS), the lysosomal enzyme deficient in mucopolysaccharidosis type II, exhibited high intrinsic activity and degraded accumulated substrates in both IDS-deficient cell and in vivo models. ETV substantially improved brain delivery of IDS in a preclinical model of disease, enabling enhanced cellular distribution to neurons, astrocytes, and microglia throughout the brain. Improved brain exposure for ETV:IDS translated to a reduction in accumulated substrates in these CNS cell types and peripheral tissues and resulted in a complete correction of downstream disease-relevant pathologies in the brain, including secondary accumulation of lysosomal lipids, perturbed gene expression, neuroinflammation, and neuroaxonal damage. These data highlight the therapeutic potential of the ETV platform for LSDs and provide preclinical proof of concept for TV-enabled therapeutics to treat CNS diseases more broadly.

摘要

大多数溶酶体贮积症(LSD)都涉及中枢神经系统(CNS)的进行性损害,这是由于溶酶体酶的缺乏所致。神经元溶酶体贮积症的治疗仍然是一个巨大的挑战,因为已批准的静脉内给予的酶治疗在改变 CNS 疾病方面无效,因为它们不能有效地穿过血脑屏障(BBB)。我们描述了一种增加酶替代疗法脑暴露的治疗平台。酶转运载体(ETV)是一种与 Fc 结构域融合的溶酶体酶,该 Fc 结构域经过工程改造以与转铁蛋白受体结合,从而促进受体介导的穿过 BBB 的胞吞作用。我们证明,含有艾杜糖-2-硫酸酯酶(ETV:IDS)的 ETV 融合物,即粘多糖贮积症 II 型中缺乏的溶酶体酶,具有很高的固有活性,并在 IDS 缺陷细胞和体内模型中降解积累的底物。ETV 在疾病的临床前模型中大大改善了 IDS 的脑递送,使细胞分布到神经元、星形胶质细胞和小胶质细胞在整个大脑中得到增强。ETV 在大脑中的暴露增加转化为这些 CNS 细胞类型和外周组织中积累的底物减少,并导致大脑中与疾病相关的下游病理学完全纠正,包括溶酶体脂质的继发性积累、基因表达失调、神经炎症和神经轴突损伤。这些数据突出了 ETV 平台治疗 LSD 的治疗潜力,并为 TV 使能治疗更广泛地治疗 CNS 疾病提供了临床前概念验证。

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