title: Post-intoxication inhibition of botulinum neurotoxin serotype A within neurons by small-molecule, non-peptidic inhibitors.
abstract: Botulinum neurotoxins (BoNTs) comprise seven distinct serotypes that inhibit the release of neurotransmitter across neuromuscular junctions, resulting in potentially fatal flaccid paralysis. BoNT serotype A (BoNT/A), which targets synaptosomal-associated protein of 25kDa (SNAP-25), is particularly long-lived within neurons and requires a longer time for recovery of neuromuscular function. There are currently no treatments available to counteract BoNT/A after it has entered the neuronal cytosol. In this study, we examined the ability of small molecule non-peptidic inhibitors (SMNPIs) to prevent SNAP-25 cleavage post-intoxication of neurons. The progressive cleavage of SNAP-25 observed over 5 h following 1 h BoNT/A intoxication was prevented by addition of SMNPIs. In contrast, anti-BoNT/A neutralizing antibodies that strongly inhibited SNAP-25 cleavage when added during intoxication were completely ineffective when added post-intoxication. Although Bafilomycin A1, which blocks entry of BoNT/A into the cytosol by preventing endosomal acidification, inhibited SNAP-25 cleavage post-intoxication, the degree of inhibition was significantly reduced versus addition both during and after intoxication. Post-intoxication application of SMNPIs, on the other hand, was nearly as effective as application both during and after intoxication. Taken together, the results indicate that competitive SMNPIs of BoNT/A light chain can be effective within neurons post-intoxication.
authors: U.S. Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, MD 21702; USA. gordon.ruthel@amedd.army.mil
authors: Gordon
authors: G
authors: Ruthel
authors: James C
authors: JC
authors: Burnett
authors: Jonathan E
authors: JE
authors: Nuss
authors: Laura M
authors: LM
authors: Wanner
authors: Lyal E
authors: LE
authors: Tressler
authors: Edna
authors: E
authors: Torres-Melendez
authors: Sarah J
authors: SJ
authors: Sandwick
authors: Cary J
authors: CJ
authors: Retterer
authors: Sina
authors: S
authors: Bavari
mesh_terms: D000157:Aconitine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D019274:Botulinum Toxins, Type A / Q000037:antagonists & inhibitors*; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D002642:Chick Embryo; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D007093:Imidazoles / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D018942:Macrolides / Q000008:administration & dosage / Q000494:pharmacology; D015394:Molecular Structure; D009046:Motor Neurons / Q000187:drug effects* / Q000378:metabolism; D010797:Phthalimides / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D054852:Small Molecule Libraries / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D013116:Spinal Cord / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D050825:Synaptosomal-Associated Protein 25 / Q000378:metabolism; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism
chemical_list: D007093:Imidazoles; D018942:Macrolides; C581288:NSC 104999; D010797:Phthalimides; D054852:Small Molecule Libraries; D050825:Synaptosomal-Associated Protein 25; C109503:heteratisine; C040929:bafilomycin A1; D019274:Botulinum Toxins, Type A; D000157:Aconitine