Nanoparticle Distributed Intravenous Enzyme Replacement Therapy (NanoDIVERT) - PROJECT ABSTRACT Enzyme replacement therapy (ERT) has been successful in ameliorating symptoms of patients with non- neuropathic lysosomal storage disorders (LSDs), making it a viable therapeutic approach for these rare, orphan genetic diseases. Essentially, patients receive intravenous (IV) infusions of endogenous enzymes that are either present at low concentration, missing entirely, or misfolded, and therefore dysfunctional due to their genetic disease. Despite its promise in the clinic, ERT cannot be used to treat 50-70% of LSDs with central nervous system manifestation due to the blood-brain barrier (BBB) which prevents the passage of recombinant enzymes from the blood into the brain. One of these diseases and the focus of this proposal, GM1 gangliosidosis, arises from variants in GLB1 that leads to decreased production of lysosomal β-galactosidase (βgal). Its most common form results in mortality between the ages of 2 and 4. Recently, our laboratory has created nanoparticle vesicles, called polymersomes, capable of encapsulating and delivering βgal to lysosomes of GM1-affected cells, where the delivered enzyme maintains its activity. Preliminary data in a feline model of GM1 gangliosidosis shows that with the addition of an apolipoprotein on the surface, polymersomes transport active βgal across the BBB within 48 hours after an intravenous forelimb injection. This approach to treatment, titled nanoparticle distributed IV ERT (NanoDIVERT), can potentially extend ERT into the central nervous system, which could impact not only GM1 gangliosidosis but also other orphan neuropathic LSDs. To further test the applicability of the nanoparticle- mediated approach to IV ERT, we will optimize in vivo performance. Specifically, we aim to increase delivery to the brain and determine the most appropriate dosing for therapeutic effects. We aim to initially optimize NanoDIVERT in a murine model of GM1 gangliosidosis, for testing in greater animal numbers, before scaling up to large animal models. The outcome of these studies could enable the development of a clinically relevant ERT for GM1 gangliosidosis and other neuropathic LSDs for the first time.
