title: Mastoparan-7 rescues botulinum toxin-A poisoned neurons in a mouse spinal cord cell culture model.
abstract: Botulinum neurotoxin serotype A (BoNT/A) is the most potent poison of biological origin known to mankind. The toxicity of BoNT/A is due to the inhibition of neurotransmission at cholinergic synapses; this is responsible for the symptom of flaccid paralysis at peripheral neuromuscular junctions. At a molecular level, the BoNT/A effect is due to its inhibition of stimulated acetylcholine (ACh) release from presynaptic nerve terminals. Currently, there is no antidote available to rescue BoNT/A-poisoned synapses. Here, we report an example of rescuing botulinum-poisoned cultured mouse spinal cord neurons by treatment with Mastoparan-7 (Mas-7), which is known to be a phospholipase A2 activator compound. Mas-7, a naturally occurring bee venom peptide, was delivered to botulinum-poisoned neurons via a drug delivery vehicle (DDV) construct prepared using the recombinant non-toxic heavy chain (HC) fragment of BoNT/A itself. In this method, the BoNT/A HC component in the DDV served as a neuron specific drug targeting molecule. We found that Mas-7 delivered into BoNT/A intoxicated spinal cord cells restored over 40% their property of stimulated neurotransmitter release. Rescue from cell poisoning did not occur from inhibition of the endopeptidase activity of BoNT/A light chain (LC) against its well-known substrate, SNAP-25 that is mechanistically involved in the cholinergic neuroexocytosis process. Rather, Mas-7 induced a physiological host response apparently unrelated to SNAP-25, but linked to the phospholipase-mediated signal transduction pathway.
authors.affiliation: Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Radharaman
authors.initials: R
authors.lastname: Ray
authors.forename: Bal Ram
authors.initials: BR
authors.lastname: Singh
authors.forename: Prabhati
authors.initials: P
authors.lastname: Ray
mesh_terms: D000818:Animals; D001514:Bee Venoms / Q000737:chemistry / Q000494:pharmacology*; D019274:Botulinum Toxins, Type A / Q000737:chemistry / Q000633:toxicity*; D002478:Cells, Cultured; D016503:Drug Delivery Systems; D015151:Immunoblotting; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000187:drug effects*; D010740:Phospholipases / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013116:Spinal Cord / Q000187:drug effects / Q000473:pathology*; D009435:Synaptic Transmission / Q000187:drug effects; D050825:Synaptosomal-Associated Protein 25 / Q000378:metabolism
chemical_list: D001514:Bee Venoms; C494209:Snap25 protein, mouse; D050825:Synaptosomal-Associated Protein 25; D010740:Phospholipases; D019274:Botulinum Toxins, Type A
keywords: Botulinum neurotoxin; Drug delivery vehicle; Mastoparan-7; Neurons; Rescue of botulism