title: Re-assembled botulinum neurotoxin inhibits CNS functions without systemic toxicity.
abstract: The therapeutic potential of botulinum neurotoxin type A (BoNT/A) has recently been widely recognized. BoNT/A acts to silence synaptic transmission via specific proteolytic cleavage of an essential neuronal protein, SNAP25. The advantages of BoNT/A-mediated synaptic silencing include very long duration, high potency and localized action. However, there is a fear of possible side-effects of BoNT/A due to its diffusible nature which may lead to neuromuscular blockade away from the injection site. We recently developed a "protein-stapling" technology which allows re-assembly of BoNT/A from two separate fragments. This technology allowed, for the first time, safe production of this popular neuronal silencing agent. Here we evaluated the re-assembled toxin in several CNS assays and assessed its systemic effects in an animal model. Our results show that the re-assembled toxin is potent in inhibiting CNS function at 1 nM concentration but surprisingly does not exhibit systemic toxicity after intraperitoneal injection even at 200 ng/kg dose. This shows that the re-assembled toxin represents a uniquely safe tool for neuroscience research and future medical applications.
authors: Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK. eferrari@mrc-lmb.cam.ac.uk
authors: Enrico
authors: E
authors: Ferrari
authors: Elizabeth S
authors: ES
authors: Maywood
authors: Laura
authors: L
authors: Restani
authors: Matteo
authors: M
authors: Caleo
authors: Marco
authors: M
authors: Pirazzini
authors: Ornella
authors: O
authors: Rossetto
authors: Michael H
authors: MH
authors: Hastings
authors: Dhevahi
authors: D
authors: Niranjan
authors: Giampietro
authors: G
authors: Schiavo
authors: Bazbek
authors: B
authors: Davletov
mesh_terms: D000818:Animals; D019274:Botulinum Toxins, Type A / Q000187:drug effects*; D002490:Central Nervous System / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D015151:Immunoblotting; D008163:Luminescent Measurements; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009498:Neurotoxins / Q000633:toxicity*; D051381:Rats; D009435:Synaptic Transmission / Q000187:drug effects; D050825:Synaptosomal-Associated Protein 25 / Q000235:genetics / Q000378:metabolism
chemical_list: D009498:Neurotoxins; C494210:Snap25 protein, rat; D050825:Synaptosomal-Associated Protein 25; D019274:Botulinum Toxins, Type A