Steger L D, Desnick R J
Biochim Biophys Acta. 1977 Feb 4;464(3):530-46. doi: 10.1016/0005-2736(77)90028-1.
Entrapment of enzyme in liposomes, biodegradable lipid vesicles, offers an intriguing strategy for the intracellular delivery of these macromolecules to the lysosomal apparatus for enzyme replacement endeavors in selected lysosomal storage diseases. Therefore, the in vivo tissue and subcellular fate and effect on the subcellular distribution of endogenous lysosomal hydrolases was determined following intravenous administration of beta-glucuronidase entrapped in positively and negatively charged liposomes into C3H/HeJ beta-glucuronidase-deficient mice. Enzyme entrapped in negatively charged liposomes was rapidly cleared from the circulation (t1/2 approximately 4 min); maximal tissue recovery, 75% of dose, was detedtec in the liver at 1 h, was maintained fro 48 h and then gradually declined to non-detectable levels by 8 days. A similar circulatory clearance and reciprocal hepatic uptake was observed fro positively charged liposomes; however, the beta-glucuronidase was retained in murine liver for 11 days. Significant activity, 15% of dose, was found in the kidneys up to 1 and 4 days post-injection of positively and negatively charged liposomes, respectively. No activity was recovered in neural or other visceral tissues except in spleen and lungs (less than 5% of the dose). Exogenous beta-glucuronidase activity administered in negatively charged liposomes was primarily localized in the lysosomally-enriched hepatic subcellular fraction, compared to the predominantly soluble localization of exogenous activity entrapped in positively charged liposomes. Administration of negatively charged liposomes caused no detectable change in the subcellular localization of several endogenous lysosomal hydrolase activities compared to their distribution in untreated mice. In contrast, a marked but temporary translocation of these hydrolase activities into the soluble fraction was observed following the administration of positively charged liposomes, identifying possible deleterious effects on cellular physiology.
将酶包裹于脂质体（可生物降解的脂质囊泡）中，为将这些大分子细胞内递送至溶酶体装置以用于特定溶酶体贮积病的酶替代治疗提供了一种引人关注的策略。因此，在将包裹于带正电荷和负电荷脂质体中的β-葡萄糖醛酸酶静脉注射给C3H/HeJβ-葡萄糖醛酸酶缺陷小鼠后，测定了其在体内的组织和亚细胞命运以及对内源性溶酶体水解酶亚细胞分布的影响。包裹于带负电荷脂质体中的酶迅速从循环中清除（半衰期约4分钟）；在1小时时肝脏中检测到最大组织回收率为剂量的75%，在48小时内保持该水平，然后逐渐下降，到8天时降至不可检测水平。带正电荷脂质体也观察到类似的循环清除和相应的肝脏摄取；然而，β-葡萄糖醛酸酶在小鼠肝脏中保留了11天。分别在注射带正电荷和负电荷脂质体后1天和4天时，在肾脏中发现了显著活性，分别为剂量的15%。除脾脏和肺（低于剂量的5%）外，在神经或其他内脏组织中未回收活性。与包裹于带正电荷脂质体中的外源性活性主要为可溶性定位相比，包裹于带负电荷脂质体中的外源性β-葡萄糖醛酸酶活性主要定位于富含溶酶体的肝脏亚细胞组分中。与未处理小鼠中几种内源性溶酶体水解酶活性的亚细胞定位分布相比，注射带负电荷脂质体未引起可检测到的变化。相反，在注射带正电荷脂质体后，观察到这些水解酶活性显著但暂时转移至可溶组分中，这表明可能对细胞生理学有有害影响。
