title: Structural and Functional Interactions between Transient Receptor Potential Vanilloid Subfamily 1 and Botulinum Neurotoxin Serotype A.
abstract: BACKGROUND
  Botulinum neurotoxins are produced by Clostridium botulinum bacteria. There are eight serologically distinct botulinum neurotoxin isoforms (serotypes A-H). Currently, botulinum neurotoxin serotype A (BoNT⁄A) is commonly used for the treatment of many disorders, such as hyperactive musculoskeletal disorders, dystonia, and pain. However, the effectiveness of BoNT⁄A for pain alleviation and the mechanisms that mediate the analgesic effects of BoNT⁄A remain unclear. To define the antinociceptive mechanisms by which BoNT/A functions, the interactions between BoNT⁄A and the transient receptor potential vanilloid subfamily 1 (TRPV1) were investigated using immunofluorescence, co-immunoprecipitation, and western blot analysis in primary mouse embryonic dorsal root ganglion neuronal cultures.
  
  
  RESULTS
  1) Three-week-old cultured dorsal root ganglion neurons highly expressed transient TRPV1, synaptic vesicle 2A (SV2A) and synaptosomal-associated protein 25 (SNAP-25). SV2A and SNAP-25 are the binding receptor and target protein, respectively, of BoNT⁄A. 2) TRPV1 colocalized with both BoNT⁄A and cleaved SNAP-25 when BoNT⁄A was added to dorsal root ganglia neuronal cultures. 3) After 24 hours of BoNT⁄A treatment (1 nmol⁄l), both TRPV1 and BoNT⁄A positive bands were detected in western blots of immunoprecipitated pellets. 4) Blocking TRPV1 with a specific antibody decreased the cleavage of SNAP-25 by BoNT⁄A.
  
  
  CONCLUSIONS
  BoNT/A interacts with TRPV1 both structurally and functionally in cultured mouse embryonic dorsal root ganglion neurons. These results suggest that an alternative mechanism is used by BoNT⁄A to mediate pain relief.
authors.affiliation: Department of Pathophysiology, Shanxi Medical University, Taiyuan, Shanxi, China.|Department of Physiology and Pharmacology, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Xiaqing
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Physiology and Pharmacology, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Coffield
mesh_terms: D000818:Animals; D015153:Blotting, Western; D019274:Botulinum Toxins, Type A / Q000737:chemistry / Q000378:metabolism*; D002478:Cells, Cultured; D003013:Clostridium / Q000378:metabolism; D005727:Ganglia, Spinal / Q000166:cytology; D047468:Immunoprecipitation; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D011485:Protein Binding; D065288:Serogroup; D050825:Synaptosomal-Associated Protein 25 / Q000235:genetics / Q000378:metabolism; D050916:TRPV Cation Channels / Q000737:chemistry / Q000378:metabolism*
chemical_list: D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; C489614:Sv2a protein, mouse; D050825:Synaptosomal-Associated Protein 25; D050916:TRPV Cation Channels; C494484:TRPV1 receptor; D019274:Botulinum Toxins, Type A