Botulinum Neurotoxins

AbstractBotulinum neurotoxins (BoNTs) are Janus‐faced biological agents. They are the most poisonous substances known and the causative agents of botulism, a deadly neuroparalytic syndrome of animals and humans. Owing to their potency, BoNTs have the potential to be used as biological weapons. At the same time, they are effective therapeutics for a variety of human neurological disorders and aesthetic medicine. In addition, the understanding of BoNT mechanism of action has provided great contributions to the study of the general principles of neuronal physiology. BoNTs were discovered more than a century ago, but they are still actively studied, both to identify effective countermeasures and mostly to expand the landscape of their clinical use. BoNT nomenclature has been recently revised owing to the identification of several BoNT isoforms via next‐generation sequencing techniques. The reason behind such variability among BoNTs remains elusive.Key ConceptsBotulinum neurotoxins are exotoxins produced by neurotoxigenic bacterial strains of the genusClostridium.Botulinum neurotoxins are metalloprotease causing botulism, a deadly neuroparalytic syndrome affecting vertebrates.Botulinum neurotoxins are a large and growing family of variants called serotypes, subtypes or mosaics according to their immunological and amino acid composition.In spite of their variability, botulinum neurotoxins have a highly conserved structure and a common mechanism of action.Botulinum neurotoxins block neurotransmitter release at peripheral nerve terminals causing flaccid paralysis and autonomic dysfunctions.Botulinum neurotoxins are Janus‐faced biological agents, being potential bioweapons and very effective therapeutics at the same time.Botulinum neurotoxins type A1 and B1 are used in human therapy to attenuate hyperactive peripheral nerve terminals.Botulinum neurotoxin type A1 is a best seller treatment in aesthetic medicine.