title: Longer-acting and highly potent chimaeric inhibitors of excessive exocytosis created with domains from botulinum neurotoxin A and B.
abstract: Various human neurogenic hyper-excitability disorders are successfully treated with type A or B BoNT (botulinum neurotoxin). The BoNT/A complex is widely used because of its longer-lasting benefits; also, autonomic side-effects are more often reported for BoNT/B. To establish if this distinct effect of BoNT/B could be exploited therapeutically, BoNT/A was modified so that it would bind the more abundant BoNT/B acceptor in rodents while retaining its desirable persistent action. The advantageous protease and translocation domain of BoNT/A were recombinantly combined with the acceptor-binding moiety of type B [H(C)/B (C-terminal half of BoNT/B heavy chain)], creating the chimaera AB. This purified protein bound the BoNT/B acceptor, displayed enhanced capability relative to type A for intraneuronally delivering its protease, cleaved SNAP-25 (synaptosome-associated protein of 25 kDa) and induced a more prolonged neuromuscular paralysis than BoNT/A in mice. The BA chimaera, generated by substituting H(C)/A (C-terminal half of BoNT/A heavy chain) into BoNT/B, exhibited an extremely high specific activity, delivered the BoNT/B protease via the BoNT/A acceptor into neurons, or fibroblast-like synoviocytes that lack SNAP-25, cleaving the requisite isoforms of VAMP (vesicle-associated membrane protein). Both chimaeras inhibited neurotransmission in murine bladder smooth muscle. BA has the unique ability to reduce exocytosis from non-neuronal cells expressing the BoNT/A-acceptor and utilising VAMP, but not SNAP-25, in exocytosis.
authors.affiliation: International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Ireland.
authors.forename: Jiafu
authors.initials: J
authors.lastname: Wang
authors.forename: Tomas H
authors.initials: TH
authors.lastname: Zurawski
authors.forename: MacDara O
authors.initials: MO
authors.lastname: Bodeker
authors.forename: Jianghui
authors.initials: J
authors.lastname: Meng
authors.forename: Sanjay
authors.initials: S
authors.lastname: Boddul
authors.forename: K Roger
authors.initials: KR
authors.lastname: Aoki
authors.forename: J Oliver
authors.initials: JO
authors.lastname: Dolly
mesh_terms: D000818:Animals; D001905:Botulinum Toxins / Q000235:genetics*; D019274:Botulinum Toxins, Type A / Q000235:genetics*; D002478:Cells, Cultured; D005089:Exocytosis / Q000187:drug effects*; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D051379:Mice; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D009469:Neuromuscular Junction / Q000187:drug effects / Q000503:physiopathology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D010243:Paralysis / Q000139:chemically induced; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism; D010791:Phrenic Nerve / Q000187:drug effects / Q000503:physiopathology; D017434:Protein Structure, Tertiary; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000494:pharmacology*; D009435:Synaptic Transmission / Q000187:drug effects; D050825:Synaptosomal-Associated Protein 25 / Q000378:metabolism; D013583:Synovial Membrane / Q000166:cytology; D001743:Urinary Bladder / Q000187:drug effects / Q000502:physiology; D050988:Vesicle-Associated Membrane Protein 2 / Q000235:genetics / Q000378:metabolism
chemical_list: D011993:Recombinant Fusion Proteins; D050825:Synaptosomal-Associated Protein 25; D050988:Vesicle-Associated Membrane Protein 2; C096323:rimabotulinumtoxinB; D010447:Peptide Hydrolases; D001905:Botulinum Toxins; D019274:Botulinum Toxins, Type A