Enzyme replacement therapy with recombinant pro-CTSD (cathepsin D) corrects defective proteolysis and autophagy in neuronal ceroid lipofuscinosis
Enzyme replacement therapy with recombinant pro-CTSD (cathepsin D) corrects defective proteolysis and autophagy in neuronal ceroid lipofuscinosis
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DOI：
10.1080/15548627.2019.1637200
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发表时间：
2019-07-16
期刊：
影响因子：
13.3
通讯作者：
Saftig, Paul
中科院分区：
文献类型：
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作者：
Marques, Andre R. A.;Di Spiezio, Alessandro;Saftig, Paul
CTSD(Cathepsin D)是一种主要的溶酶体蛋白水解酶，通过翻转吞噬、吞噬和自噬的底物来维持细胞的蛋白稳定。因此，CTSD缺乏会导致溶酶体自噬机制的严重损害。在小鼠和人类中，CTSD功能障碍是神经元蜡样脂褐素沉积症(NCL)的先天性变异(CLN10)的基础。NCL是一种不同的溶酶体储存障碍(LSD)，具有不同的特征，即蛋白聚集物和类油脂褐素积聚导致神经变性和失明。最成熟和临床认可的治疗LSD的方法是酶替代疗法(ERT)，目的是用外源应用的重组蛋白取代有缺陷的水解酶。在这里，我们揭示了在哺乳动物表达系统中产生的重组人ProCTSD可以被各种细胞模型有效地摄取，正确地靶向于溶酶体，并加工成活性成熟的蛋白酶。在原理验证实验中，我们提供了重组人CTSD(RhCTSD)能够改善CTSD缺陷的海马片体外培养和体内视网膜细胞的生化表型的证据。此外，我们还证明，在小鼠CLN10模型中，给予重组人CTSD可以纠正内脏和中枢神经系统(CNS)溶酶体肥大、储存堆积和自噬通量受损的现象。我们证实，将重组酶直接输送到中枢神经系统是改善神经病理和延长寿命所必需的。综上所述，这些数据支持了重组人CTSD在NCL治疗中应用的临床前研究的继续。
CTSD (cathepsin D) is one of the major lysosomal proteases indispensable for the maintenance of cellular proteostasis by turning over substrates of endocytosis, phagocytosis and autophagy. Consequently, CTSD deficiency leads to a strong impairment of the lysosomal-autophagy machinery. In mice and humans CTSD dysfunction underlies the congenital variant (CLN10) of neuronal ceroid lipofuscinosis (NCL). NCLs are distinct lysosomal storage disorders (LSDs) sharing various hallmarks, namely accumulation of protein aggregates and ceroid lipofuscin leading to neurodegeneration and blindness. The most established and clinically approved approach to treat LSDs is enzyme replacement therapy (ERT) aiming to replace the defective hydrolase with an exogenously applied recombinant protein. Here we reveal that recombinant human pro-CTSD produced in a mammalian expression system can be efficiently taken up by a variety of cell models, is correctly targeted to lysosomes and processed to the active mature form of the protease. In proof-of-principle experiments we provide evidence that recombinant human CTSD (rhCTSD) can improve the biochemical phenotype of CTSD-deficient hippocampal slice cultures in vitro and retinal cells in vivo. Furthermore, we demonstrate that dosing of rhCTSD in the murine CLN10 model leads to a correction of lysosomal hypertrophy, storage accumulation and impaired autophagic flux in the viscera and central nervous system (CNS). We establish that direct delivery of the recombinant protease to the CNS is required for improvement of neuropathology and lifespan extension. Together these data support the continuation of the pre-clinical studies for the application of rhCTSD in the treatment of NCL.