Encapsulation of Acidic Alpha-Glucosidase

Abstract

Lysosomal storage diseases are a group of heritable metabolic disorders characterized by a deficiency of specific enzymes within the lysosome, leading to the accumulation of undegraded substrate, which results in cellular damage and dysfunction. There are over 50 types of LSD, but the most common one that occurs in babies and children is pompa disease. Pompa disease is caused by the deficiency of acid α-glucosidase enzyme, leading to glycogen buildup in lysosomes of different tissues and organs. This condition manifests in symptoms such as muscle weakness, respiratory issues, and cardiac abnormalities. The current treatment option is enzyme replacement therapy, which involves the intravenous administration of the deficient enzyme. However, this treatment suffers from different side effects, such as immunogenicity, poor bioavailability of the enzymes in the lysosomes where they are needed, and low efficacy levels. To overcome these side effects and improve the treatment efficacy, we propose enzyme encapsulation into the liposomes as the main strategy. In this project, we aim to develop liposomes with high encapsulation efficiency for the enzyme while preserving the enzyme's activity. To achieve this goal, we investigated the manufacturing process and identified the optimum manufacturing conditions as well as optimal lipid composition that can allow us to achieve high efficiency in the encapsulation process. In the liposome preparation, the particles were characterized and purified, and the encapsulation efficiency was determined using the direct method (HPLC). Additionally, we assessed the activity of the enzyme encapsulated in the particles, and we evaluated enzyme activity under various conditions and with different substances. We successfully elucidated the optimum manufacturing condition and identified the ideal lipid composition having a high encapsulation efficiency of up to 50 %. The encapsulation strategy is based on the induction of charge-based interaction between protein and liposome, which involves electrostatic interaction between the positively charged lipids and the negatively charged acidic alpha-glucosidase used in this study. The activity of the enzymes was high even after encapsulation. Our data confirm that the efficient encapsulation of the enzymes into lipid vesicles is possible.