Quantitative analysis of recombinant glucocerebrosidase brain delivery via lipid nanoparticles

Gaucher disease (GD), the most prevalent genetic lysosomal storage disease, is characterized by the accumulation of glucosylceramide, mainly in monocyte-derived cells, due to deficient activity of lysosomal acid-ß-glucocerebrosidase (GCase). The disease is heterogeneous and may vary from a very mild visceral disease to a severe neuronopathic disease, with very early death during the first years of life. Two therapeutic modalities are in use today; enzyme replacement therapy (ERT) and substrate reduction therapy (SRT). Neither of the two modalities are applicable for patients with the neuronopathic forms of GD. While the infused enzyme in ERT cannot cross the blood–brain-barrier, SRT is not suitable for young patients. Herein, we investigated novel approaches to deliver recombinant GCase (rGCase) into the brain using lipid nanoparticles (LNPs). These LNPs were composed of a mixture of negative, positive and zwitterion phospholipids and were delivered intranasally into the brains of mice. A quantitative analysis performed intranasally in mice revealed a dramatic accumulation of the enzyme that was formulated into the LNPs in the brains of the mice (3.91%?±?0.3% injected dose (ID)/mg tissue)) versus the free enzyme (0.29%?±?0.07, % ID/mg tissue). The administrated particle-delivered enzymes were able to enter the brain parenchyma and accumulate in the CD11b⁺ cells, which are the target cells in GD. When supplied to GD-derived skin fibroblasts, a 35%?±?1.2 increase in intracellular GCase activity was measured only with the LNP-encapsulated enzyme. This strategy may pave the way for novel therapeutic modalities to treat GD and other diseases such as Alzheimer’s and Parkinson’s.