Adeno-associated virus transfer of a gene encoding SNAP-25 resistant to botulinum toxin A attenuates neuromuscular paralysis associated with botulism.
Advances in viral gene therapy have opened new possibilities for treating a range of motor neuron diseases, but these have not yet been translated into clinically applicable therapies because of difficulties in delivery to susceptible/damaged neurons, ambiguities in the identity of gene(s) implicated, and a paucity of means to quantify any physiological improvement. Most of these hurdles can be overcome by using the neuromuscular paralysis induced by botulinum neurotoxin type A (BoNT/A) as a prototype disease. Furthermore, because human botulism, occasionally fatal, causes prolonged muscle disablement as a result of the intraneuronal persistence of the toxin's SNAP-25 (S25)-cleaving protease, development of a genetic approach could lead to a potential treatment for this debilitating disease. Adeno-associated viral delivery of a cleavage-resistant S25 gene (S25-R198T) to chromaffin cells in vitro yielded exocytotically active S25-R198T that diminished subsequent blockade by BoNT/A of evoked catecholamine release. Evaluation in vivo, by administering this virus into rat spinal cord before injecting BoNT/A, showed a decreased inhibition of acetylcholine release as reflected in elevated retention of neuromuscular transmission. A similar, although smaller, protection of synaptic transmission from the toxin was seen after peripherally injecting the therapeutic virus. Such therapy also curtailed nerve sprouting normally induced by BoNT/A. This first demonstration of the utility of a DNA-based therapy for botulism paves the way for further advances in its treatment and for application to genetic disorders of motor neurons.
Raghunath
Arvind
A
International Centre for Neurotherapeutics, Dublin City University, Dublin 9, Ireland.
Perez-Branguli
Francesc
F
Smith
Leonard
L
Dolly
J Oliver
JO
D000818:Animals; D019274:Botulinum Toxins, Type A / Q000494:pharmacology*; D001906:Botulism / Q000188:drug therapy; D002395:Catecholamines / Q000378:metabolism; D002478:Cells, Cultured; D019439:Chromaffin Cells; D000229:Dependovirus / Q000502:physiology; D004705:Endocytosis / Q000187:drug effects; D018014:Gene Transfer Techniques; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D009154:Mutation / Q000502:physiology; D009465:Neuromuscular Agents / Q000494:pharmacology*; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000502:physiology; D020828:Pseudobulbar Palsy / Q000139:chemically induced / Q000188:drug therapy / Q000473:pathology; D051381:Rats; D012694:Serine / Q000235:genetics; D050825:Synaptosomal-Associated Protein 25 / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D013912:Threonine / Q000235:genetics
D002395:Catecholamines; D009465:Neuromuscular Agents; D050825:Synaptosomal-Associated Protein 25; D049452:Green Fluorescent Proteins; D013912:Threonine; D012694:Serine; D019274:Botulinum Toxins, Type A