title: A novel therapeutic with two SNAP-25 inactivating proteases shows long-lasting anti-hyperalgesic activity in a rat model of neuropathic pain.
abstract: A pressing need exists for long-acting, non-addictive medicines to treat chronic pain, a major societal burden. Botulinum neurotoxin type A (BoNT/A) complex - a potent, specific and prolonged inhibitor of neuro-exocytosis - gives some relief in several pain disorders, but not for all patients. Our study objective was to modify BoNT/A to overcome its inability to block transmitter release elicited by high [Ca2+]iand increase its limited analgesic effects. This was achieved by fusing a BoNT/A gene to that for the light chain (LC) of type/E. The resultant purified protein, LC/E-BoNT/A, entered cultured sensory neurons and, unlike BoNT/A, inhibited release of calcitonin gene-related peptide evoked by capsaicin. Western blotting revealed that this improvement could be due to a more extensive truncation by LC/E of synaptosomal-associated protein of Mr = 25 k, essential for neuro-exocytosis. When tested in a rat spared nerve injury (SNI) model, a single intra-plantar (IPL) injection of LC/E-BoNT/A alleviated for ∼2 weeks mechanical and cold hyper-sensitivities, in a dose-dependent manner. The highest non-paralytic dose (75 U/Kg, IPL) proved significantly more efficacious than BoNT/A (15 U/Kg, IPL) or repeated systemic pregabalin (10 mg/Kg, intraperitoneal), a clinically-used pain modulator. Effects of repeated or delayed injections of this fusion protein highlighted its analgesic potential. Attenuation of mechanical hyperalgesia was extended by a second administration when the effect of the first had diminished. When injected 5 weeks after injury, LC/E-BoNT/A also reversed fully-established mechanical and cold hyper-sensitivity. Thus, combining advantageous features of BoNT/E and/A yields an efficacious, locally-applied and long-acting anti-hyperalgesic.
authors.affiliation: International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors.forename: Jiafu
authors.initials: J
authors.lastname: Wang
authors.affiliation: International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors.forename: Laura
authors.initials: L
authors.lastname: Casals-Diaz
authors.affiliation: International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors.forename: Tomas
authors.initials: T
authors.lastname: Zurawski
authors.affiliation: International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors.forename: Jianghui
authors.initials: J
authors.lastname: Meng
authors.affiliation: International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors.forename: Orla
authors.initials: O
authors.lastname: Moriarty
authors.affiliation: International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors.forename: John
authors.initials: J
authors.lastname: Nealon
authors.affiliation: International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors.forename: Om Prakash
authors.initials: OP
authors.lastname: Edupuganti
authors.affiliation: International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland. Electronic address: oliver.dolly@dcu.ie.
authors.forename: Oliver
authors.initials: O
authors.lastname: Dolly
mesh_terms: D000818:Animals; D001905:Botulinum Toxins / Q000737:chemistry / Q000627:therapeutic use*; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D002211:Capsaicin / Q000494:pharmacology; D002478:Cells, Cultured; D004195:Disease Models, Animal; D006930:Hyperalgesia / Q000188:drug therapy* / Q000209:etiology*; D008297:Male; D008958:Models, Molecular; D009043:Motor Activity / Q000187:drug effects; D009437:Neuralgia / Q000150:complications* / Q000188:drug therapy; D010447:Peptide Hydrolases / Q000627:therapeutic use*; D000069583:Pregabalin / Q000633:toxicity; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000627:therapeutic use; D011984:Sensory Receptor Cells / Q000187:drug effects; D050825:Synaptosomal-Associated Protein 25 / Q000378:metabolism*; D013997:Time Factors; D012668:Trigeminal Ganglion / Q000166:cytology
chemical_list: D011993:Recombinant Fusion Proteins; D050825:Synaptosomal-Associated Protein 25; D000069583:Pregabalin; D010447:Peptide Hydrolases; D001905:Botulinum Toxins; C096324:botulinum toxin type C; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin; C096326:botulinum toxin type E
keywords: Analgesics; Botulinum neurotoxin; Neuropathic pain; SNAREs