(476d) Evaluation of Enzyme-Loaded Nano-Polymersome Treatment on Neurodegenerative Disease

Delivery of therapeutics to the brain through non-invasive administration is a difficult task due to the blood-brain barrier (BBB), which prevents the transport of 98% of therapeutics. In GM1 gangliosidosis, patients are missing β-galactosidase (βgal), an enzyme necessary for cellular digestion, with major central nervous system (CNS) manifestation. GM1 gangliosidosis is fatal in infancy with no clinically available treatment. We are designing and characterizing the first nanoparticle-mediated treatment of GM1 gangliosidosis using self-assembled polymersomes due to their high physiological stability and tunable release for IV enzyme delivery. When coupled with apolipoprotein, delivery through the BBB and to the lysosome of neural cells will occur, treating patients without invasive surgery

Polymersomes formed using poly(ethylene glycol)-b- poly(lactic acid) (PEGPLA) can encapsulate, protect, and deliver the lysosomal enzyme, βgal, under low-pH conditions. PEGPLA polymersomes form via solvent injection with an average diameter of 145 ± 21 nm. PEGPLA polymersomes encapsulate βgal at 72.0 ± 12.2% efficiency and demonstrate simultaneous encapsulation and ligand attachment at 86.7 ± 11.6% efficiency. Amine-reactive PEG facilitated the attachment of CF 350 Amine, a blue fluorescent ligand, for fluorescent imaging, and apolipoprotein E (ApoE), a target to the LDLR family of receptors, for BBB delivery, to the polymersome surface. In vitro, PEGPLA polymersomes demonstrate limited release in physiologic environment, pH 7.4, with a burst release upon membrane poration in lysosomal environment, pH 4.8, which is as desired for delivery of βgal to the lysosome. Cellular studies, using GM1 gangliosidosis-diseased fibroblasts, confirm that βgal-loaded polymersomes increase enzyme activity to normal levels with doses as low as 0.7 mg/cm². The addition of apolipoprotein E as a targeting ligand decreases the effective dose to 0.175 mg/cm², indicative that receptor mediated endocytosis is effective.

Results demonstrate strict control over carrier size formed, therapeutic payload, release location, and ligand attachment possible when utilizing polymersomes as an enzyme delivery vehicle. This novel carrier provides a brain delivery platform for currently untreatable diseases and has the potential to cause a paradigm shift in the way we treat the central nervous system. Initial animal studies are promising towards the goal of creating the first clinical treatment for GM1 gangliosidosis, using a combination of enzyme replacement therapy and nanotechnology methods to cross the BBB.