Long-Term Correction of Sandhoff Disease Following Intravenous Delivery of rAAV9 to Mouse Neonates

Abstract

G M2 gangliosidoses are severe neurodegenerative disorders resulting from a deficiency in β-hexosaminidase A activity and lacking effective therapies. Using a Sandhoff disease (SD) mouse model (Hexb −/− ) of the G M2 gangliosidoses, we tested the potential of systemically delivered adeno-associated virus 9 (AAV9) expressing Hexb cDNA to correct the neurological phenotype. Neonatal or adult SD and normal mice were intravenously injected with AAV9-HexB or -LacZ and monitored for serum β-hexosaminidase activity, motor function, and survival. Brain G M2 ganglioside, β-hexosaminidase activity, and inflammation were assessed at experimental week 43, or an earlier humane end point. SD mice injected with AAV9-LacZ died by 17 weeks of age, whereas all neonatal AAV9-HexB-treated SD mice survived until 43 weeks (P < 0.0001) with only three exhibiting neurological dysfunction. SD mice treated as adults with AAV9-HexB died between 17 and 35 weeks. Neonatal SD-HexB-treated mice had a significant increase in brain β-hexosaminidase activity, and a reduction in G M2 ganglioside storage and neuroinflammation compared to adult SD-HexB-and SD-LacZ-treated groups. However, at 43 weeks, 8 of 10 neonatal-HexB injected control and SD mice exhibited liver or lung tumors. This study demonstrates the potential for long-term correction of SD and other G M2 gangliosidoses through early rAAV9 based systemic gene therapy.

Gene therapy decreases seizures in a model of Incontinentia pigmenti

“…The ectopic expression of tight junction proteins, such as claudin-1, has been reported to repair a leaky BBB and may curb epileptogenesis. 34 In contrast, the vector doses that we administered to mice (7-60 3 10 12 genomic particles/kg body weight) fall into the range that is used with clinically approved vectors. [27][28][29] Therefore, it seems prudent to avoid off-target expression of Nemo in sensitive cells, such as neurons, peripheral endothelial cells, and in hepatocytes.…”

“…[30][31][32][33] Indeed, the use of high doses of other AAV vectors to transduce neural cells has been associated with an excessive rate of liver tumors in some studies. 34 In contrast, the vector doses that we administered to mice (7-60 3 10 12 genomic particles/kg body weight) fall into the range that is used with clinically approved vectors. We detected an increased amount of aggregates of lymphocytes and plasma cells in livers of the AAV-BR1-CAG-NEMO-treated group compared to the control group, although the liver tissue appeared healthy.…”

AAV9 delivering a modified human Mullerian inhibiting substance as a gene therapy in patient-derived xenografts of ovarian cancer

“…We used a gene therapy approach based on AAV9 to deliver LRMIS (16) in PDXa models as a feasible way to determine the percentage of patients responsive to MIS. The AAV9 serotype of the AAV family has been safely used to infect a range of cells and tissues, including cardiac myocytes (37), lung tissue (38), and neurons of the CNS and peripheral nervous system (17,(39)(40)(41)(42)(43), to correct a host of genetic diseases, including ALS (39, 40, 43), Parkinson's (44), Huntington's (45-51), and Sandoff (52). AAV9 has been shown to have enhanced tropism to muscles and neurons, high infectivity, and stable long-term expression, making it ideally suited for the treatment of tumors, where normal infected tissues (e.g., muscles) serve as a bioreactor-like source of therapeutic protein for long-term secretion into the circulation (53).…”

Recombinant Adeno-Associated Viral Integration and Genotoxicity: Insights from Animal Models

“…49 At the experimental end point of 43 weeks, gross examination during necropsy revealed tumors in 8/10 neonatally rAAV9-HexB-injected control and SD mice; seven animals had liver tumors, and one had multiple lung tumors. Tumors were not observed in untreated mice, but it should be noted that untreated SD mice uniformly perished, typically by 15 weeks of age.…”