Delivery of Glucosylceramidase Beta Gene Using AAV9 Vector Therapy as a Treatment Strategy in Mouse Models of Gaucher Disease

Gaucher disease (GD) is an autosomal recessive lysosomal storage disorder caused by mutations in the GBA gene. Enzyme replacement treatment is the most effective therapy available for type 1 GD patients, but it is very expensive and does not improve neurologic outcomes in type 2 and 3 GD patients. This study evaluated the effectiveness of an adeno-associated virus 9 (AAV9) vector expressing the Gba gene delivered systemically in GD mouse models. To detect the therapeutic effects of the AAV9-mediated Gba transfer on the systemic symptoms of GD, an inducible whole-body Gba knockout mouse was developed in which tamoxifen effectively induced whole-body Gba gene deletion, and the mice displayed systemic symptoms of GD. The AAV9-CMV-Gba vector, with the expression of Gba driven by the universal CMV promoter, restored GCase activity in multiple organs and prolonged the lifespan in tamoxifen-induced GD mice after intravenous injection. Mice with brain-specific Gba deletion were also included in this study as a model of neuropathic GD (nGD) and injected intraperitoneally on postnatal day 5 with the AAV9-SYN-Gba vector; this improved the GCase activity, ameliorated the neuropathological changes and extended the mean lifespan two-fold. This study demonstrates that AAV9-mediated gene transfer is a potentially effective treatment for GD.