Botulinum neurotoxin A activity is dependent upon the presence of specific gangliosides in neuroblastoma cells expressing synaptotagmin I.
Botulinum neurotoxin A (BoNT/A) is the deadliest of all known biological substances. Although its toxicity makes BoNT/A a biological warfare threat, its biologic activity makes it an increasingly useful therapeutic agent for the treatment of muscular disorders. However, almost 200 years after its discovery, the neuronal cell components required for the activity of this deadly toxin have not been unequivocally identified. In this work, neuroblastoma cells expressing synaptotagmin I, a protein shown to be bound by BoNT/A, were used to determine whether specific gangliosides were necessary for BoNT/A activity as measured by synaptosomal-associated protein of 25 kDa (SNAP-25) cleavage. Ganglioside GT1b was found to support BoNT/A activity significantly more effectively than GD1a, which was far more effective than GM1 when added to ganglioside-deficient murine cholinergic Neuro 2a or to human adrenergic SK-N-SH neuroblastoma cells. Whereas both cell lines expressed synaptotagmin I, SNAP-25 cleavage was not observed in the absence of complex gangliosides. These results indicate that 1) gangliosides are required for BoNT/A activity, 2) synaptotagmin I in the absence of gangliosides does not support BoNT/A activity, and 3) Neuro 2a cells are an efficient model system for studying the biological activity of BoNT/A.
Yowler
Brian C
BC
Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA.
Kensinger
Richard D
RD
Schengrund
Cara-Lynne
CL
D000818:Animals; D015153:Blotting, Western; D019274:Botulinum Toxins, Type A / Q000494:pharmacology*; D002135:Calcium-Binding Proteins; D002851:Chromatography, High Pressure Liquid; D005732:Gangliosides / Q000032:analysis / Q000502:physiology*; D006801:Humans; D050356:Lipid Metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D009419:Nerve Tissue Proteins / Q000378:metabolism* / Q000494:pharmacology; D009447:Neuroblastoma / Q000737:chemistry / Q000378:metabolism*; D009465:Neuromuscular Agents / Q000494:pharmacology*; D050863:Synaptotagmin I; D050857:Synaptotagmins; D013997:Time Factors; D014407:Tumor Cells, Cultured
D002135:Calcium-Binding Proteins; D005732:Gangliosides; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D009465:Neuromuscular Agents; C494310:SYT1 protein, human; D050863:Synaptotagmin I; C494311:Syt1 protein, mouse; D050857:Synaptotagmins; D019274:Botulinum Toxins, Type A