Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-8593, USA.
Mol Genet Metab. 2010 Apr;99(4):374-8. doi: 10.1016/j.ymgme.2009.12.002. Epub 2009 Dec 5.
Infantile neuronal ceroid lipofuscinosis (INCL, also known as Haltia-Santavuori disease) is a lysosomal storage disorder of infants and children characterized by blindness, seizures and a progressive neurodegenerative course. Recent clinical trials have involved neural stem cells and gene therapy directed to the central nervous system; however, enzyme replacement therapy has never been addressed. In the current paper, we describe the production of human recombinant PPT1 (the defective enzyme in INCL) by standard methods in Chinese Hamster Ovary (CHO) cells. The enzyme is largely mannose 6-phosphorylated as assessed by mannose 6-phosphate receptor binding (80% bound) and taken up rapidly by immortalized patient lymphoblasts, where clearance of PPT substrates was demonstrated (EC(50) of 0.25 nM after overnight incubation). When injected intravenously into PPT1-deficient mice, the clearance of recombinant human PPT1 from plasma was rapid, with a half-life of 10 min. Most of the injected dose was distributed to the kidney and liver and potentially corrective levels were also observed in heart, lung and spleen. Brain uptake was minimal, as expected based on experience with other intravenously administered lysosomal enzymes. The enzyme may be useful as an adjunct to central nervous system-directed therapies and could be used as a starting point for modifications designed to improve brain delivery.
婴儿神经元蜡样脂褐质沉积症（INCL，也称为哈耳蒂-桑托瓦里病）是一种婴儿和儿童的溶酶体贮积症，其特征为失明、癫痫发作和进行性神经退行性病程。最近的临床试验涉及神经干细胞和针对中枢神经系统的基因治疗；然而，酶替代疗法从未被涉及。在当前的论文中，我们描述了通过标准方法在中华仓鼠卵巢（CHO）细胞中生产人重组 PPT1（INCL 中的缺陷酶）。该酶通过甘露糖 6-磷酸受体结合（80%结合）被大量甘露糖 6-磷酸化，并被永生化的患者淋巴母细胞迅速摄取，其中证明了 PPT 底物的清除（经过过夜孵育后，EC50 为 0.25 nM）。当静脉内注射到 PPT1 缺陷型小鼠中时，重组人 PPT1 从血浆中的清除速度很快，半衰期为 10 分钟。大部分注射剂量分布在肾脏和肝脏中，在心脏、肺和脾脏中也观察到潜在的校正水平。脑摄取最小，这与其他静脉内给予的溶酶体酶的经验相符。该酶可用作中枢神经系统靶向治疗的辅助手段，也可用作旨在改善脑递药的修饰的起点。
