Adenovirus-mediated gene therapy in a mouse model of glycogen storage disease type 1a

Glycogen storage disease type 1a (GSD-1a), characterized by growth retardation, hypoglycemia, hepatomegaly, kidney enlargement, hyperlipidemia, hyperuricemia, and renal dysfunction, is caused by deficiencies in glucose-6-phosphatase (G6Pase), a key enzyme in glucose homeostasis. Over the last 20 years, dietary therapies have greatly improved the prognosis of GSD-1a patients. However, the underlying pathological process remains uncorrected and the efficacy of dietary treatment is frequently limited by poor compliance. Therefore, long-term complications still develop in adult patients. To develop future therapeutic approaches for GSD-1a, we have generated G6Pase-deficient (G6Pase(-/-)) mice that mimic the pathophysiology of human GSD-1a patients. To evaluate the feasibility of gene replacement therapy for this disorder, we have infused recombinant adenovirus containing murine G6Pase gene (Ad-mG6Pase) into G6Pase(-/-) mice. While only 15% of G6Pase(-/-) mice under glucose therapy survived weaning, a 100% survival rate was achieved when G6Pase(-/-) mice were infused with Ad-mG6Pase and 90% of which lived to 3 months of age. Hepatic G6Pase activity in Ad-mG6Pase-infused mice was restored to 19% of that in G6Pase(+/+) mice at 7 through 14 post-infusion days. Ad-mG6Pase infusion also greatly improved growth of G6Pase(-/-) mice and normalized plasma glucose, cholesterol, triglyceride, and uric acid profiles. Further, liver and kidney enlargement were less pronounced with near normal levels of glycogen depositions in both organs.

our data demonstrate that a single administration of a recombinant adenovirus vector can alleviate the clinical manifestations of glycogen storage disease type 1a in mice, suggesting that this disorder in humans can potentially be corrected by gene therapy.