Re-assembled Botulinum Neurotoxin Inhibits CNS Functions Without Systemic Toxicity

Toxins (Basel). 2011 Apr;3(4):345-55. doi: 10.3390/toxins3040345. Epub 2011 Mar 24.

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.

Keywords: BITOX; BOTOX; SNAREs; botulinum neurotoxin; nervous system; protein engineering; synapse.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Botulinum Toxins, Type A / drug effects*
  • Central Nervous System / drug effects*
  • Central Nervous System / metabolism
  • Central Nervous System / physiopathology
  • Disease Models, Animal
  • Gene Expression Regulation
  • Immunoblotting
  • Luminescent Measurements
  • Mice
  • Mice, Inbred C57BL
  • Neurons / drug effects
  • Neurons / metabolism
  • Neurotoxins / toxicity*
  • Rats
  • Synaptic Transmission / drug effects
  • Synaptosomal-Associated Protein 25 / genetics
  • Synaptosomal-Associated Protein 25 / metabolism

Substances

  • Neurotoxins
  • Snap25 protein, rat
  • Synaptosomal-Associated Protein 25
  • Botulinum Toxins, Type A