A single injection of an adeno-associated virus vector into nuclei with divergent connections results in widespread vector distribution in the brain and global correction of a neurogenetic disease.
ABSTRACT Neurogenetic disorders typically affect cells throughout the brain. Adeno-associated virus (AAV) vector-mediated transfer of a normal cDNA can correct the metabolic defects at the site of injection, but treatment of the entire brain requires widespread delivery of the normal gene and/or protein. Current methods require multiple injections for widespread distribution. However, some AAV vectors can be transported along neuronal pathways associated with the injected region. Thus, targeting widely dispersed systems in the CNS might be a pathway for gene dispersal from a limited number of sites. We tested this hypothesis in the ventral tegmental area (VTA), a region with numerous efferent and afferent projections. A single 1 mul injection resulted in transport of the vector genome to projection sites in distal parts of the brain. When compared with injections into the striatum, the VTA injection resulted in higher enzyme levels in more regions of the brain. The AAV-9 serotype vector was the most widely disseminated, but AAV-Rh.10 and AAV-1 were also transported after VTA injection. The effect on global lesions of a neurogenetic disease was tested in the mouse model of MPS VII (mucopolysaccharidosis VII), a lysosomal storage disorder. Widespread distribution of the vector genome after AAV-9 VTA injection resulted in even further distribution of the enzyme product, by secretion and uptake by surrounding cells, and complete correction of the storage lesions throughout the entire brain. This unprecedented level of correction from a single injection into the developed brain provides a potential strategy to correct a large volume of brain while minimizing the number of injections.
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ABSTRACT: Angelman syndrome is a monogenic neurologic disorder that affects 1 in 15,000 children, and is characterized by ataxia, intellectual disability, speech impairment, sleep disorders, and seizures. The disorder is caused by loss of central nervous system expression of UBE3A, a gene encoding a ubiquitin ligase. Current treatments focus on the management of symptoms, as there have not been therapies to treat the underlying molecular cause of the disease. However, this outlook is evolving with advances in molecular therapies, including artificial transcription factors a class of engineered DNA-binding proteins that have the potential to target a specific site in the genome. Here we review the recent progress and prospect of targeted gene expression therapies. Three main issues that must be addressed to advance toward human clinical trials are specificity, toxicity, and delivery. Artificial transcription factors have the potential to address these concerns on a level that meets and in some cases exceeds current small molecule therapies. We examine the possibilities of such approaches in the context of Angelman syndrome, as a template for other single-gene, neurologic disorders.BMC Neuroscience 06/2014; 15(1):76. · 3.00 Impact Factor
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ABSTRACT: Progressive debilitating neurological defects characterize feline GM1 gangliosidosis, a lysosomal storage disease caused by deficiency of lysosomal β-galactosidase. No effective therapy exists for affected children, who often die before age 5 years. An adeno-associated viral vector carrying the therapeutic gene was injected bilaterally into two brain targets (thalamus and deep cerebellar nuclei) of a feline model of GM1 gangliosidosis. Gene therapy normalized β-galactosidase activity and storage throughout the brain and spinal cord. The mean survival of 12 treated GM1 animals was >38 months, compared to 8 months for untreated animals. Seven of the eight treated animals remaining alive demonstrated normalization of disease, with abrogation of many symptoms including gait deficits and postural imbalance. Sustained correction of the GM1 gangliosidosis disease phenotype after limited intracranial targeting by gene therapy in a large animal model suggests that this approach may be useful for treating the human version of this lysosomal storage disorder.Science translational medicine 04/2014; 6(231):231ra48. · 10.76 Impact Factor
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ABSTRACT: Accumulation of amyloid beta-peptide (Aβ) in the brain is hypothesized to be a causal event leading to dementia in Alzheimer's disease (AD). Aβ vaccination removes Aβ deposits from the brain. Aβ immunotherapy, however, may cause T cell- and/or Fc-receptor-mediated brain inflammation and relocate parenchymal Aβ deposits to blood vessels leading to cerebral hemorrhages. Because catalytic antibodies do not form stable immune complexes and Aβ fragments produced by catalytic antibodies are less likely to form aggregates, Aβ-specific catalytic antibodies may have safer therapeutic profiles than reversibly-binding anti-Aβ antibodies. Additionally, catalytic antibodies may remove Aβ more efficiently than binding antibodies because a single catalytic antibody can hydrolyze thousands of Aβ molecules. We previously isolated Aβ-specific catalytic antibody, IgVL5D3, with strong Aβ-hydrolyzing activity. Here, we evaluated the prophylactic and therapeutic efficacy of brain-targeted IgVL5D3 gene delivery via recombinant adeno-associated virus serotype 9 (rAAV9) in an AD mouse model. One single injection of rAAV9-IgVL5D3 into the right ventricle of AD model mice yielded widespread, high expression of IgVL5D3 in the unilateral hemisphere. IgVL5D3 expression was readily detectable in the contralateral hemisphere but to a much lesser extent. IgVL5D3 expression was also confirmed in the cerebrospinal fluid. Prophylactic and therapeutic injection of rAAV9-IgVL5D3 reduced Aβ load in the ipsilateral hippocampus of AD model mice. No evidence of hemorrhages, increased vascular amyloid deposits, increased proinflammatory cytokines, or infiltrating T-cells in the brains was found in the experimental animals. AAV9-mediated anti-Aβ catalytic antibody brain delivery can be prophylactic and therapeutic options for AD.Molecular Neurobiology 04/2014; · 5.47 Impact Factor