Type A botulinum neurotoxin complex proteins differentially modulate host response of neuronal cells

Abstract

Type A Botulinum neurotoxin (BoNT/A), the most potent poison known to mankind, is produced by Clostridium botulinum type A as a complex with neurotoxin-associated proteins (NAPs). Currently BoNT/A in purified and complex forms are both available in therapeutic and cosmetic applications to treat neuromuscular disorders. Whereas Xeomin(®) (incobotulinumtoxin A, Merz Pharmaceuticals, Germany) is free from complexing proteins, Botox(®) (onabotulinumtoxin A, Allergan, USA) contains NAPs, which by themselves have no known role in the intracellular biochemical process involved in the blockade of neurotransmitter release. Since the fate and possible interactions of NAPs with patient tissues after intramuscular injection are not known, it was the aim of this study to evaluate the binding of BoNT/A and/or the respective NAPs to cells derived from neuronal and non-neuronal human tissues, and to further explore neuronal cell responses to different components of BoNT/A. BoNT/A alone, the complete BoNT/A complex, and the NAPs alone, all bind to neuronal SH-SY5Y cells. The BoNT/A complex and NAPs additionally bind to RMS13 skeletal muscle cells, TIB-152 lymphoblasts, Detroit 551 fibroblasts besides the SH-SY5Y cells. However, no binding to these non-neuronal cells was observed with pure BoNT/A. Although BoNT/A, both in its purified and complex forms, bind to SH-SY5Y, the intracellular responses of the SH-SY5Y cells to these BoNT/A components are not clearly understood. Examination of inflammatory cytokine released from SH-SY5Y cells revealed that BoNT/A did not increase the release of inflammatory cytokines, whereas exposure to NAPs significantly increased release of IL-6, and MCP-1, and exposure to BoNT/A complex significantly increased release of IL-6, MCP-1, IL-8, TNF-α, and RANTES vs. control, suggesting that different components of BoNT/A complex induce significantly differential host response in human neuronal cells. Results suggest that host response to different compositions of BoNT/A based therapeutics may play important role in local and systemic symptoms in patients.

Pharmaceutical, Biological, and Clinical Properties of Botulinum Neurotoxin Type A Products

“…NAPs do not play a role in toxin-induced blockade of cholinergic transmission and, until recently, were thought to be just a group of passive bystanders when injected for therapeutic and aesthetic uses. However, several lines of evidence that have examined the fate and possible interactions of NAPs with patient tissues after intramuscular injection suggest this may not be the case and that the presence of complexing proteins might be clinically relevant [65–67]. …”

“…That complexing proteins can induce an inflammatory response has recently been demonstrated in a human neuroblastoma cell line (SH-SY5Y) [67]. While pure BoNT/A, BoNT/A complex, and NAPs all bound to the SH-SY5Y neuronal cells, the BoNTA complex and NAPs additionally bound to lymphoblasts and fibroblasts.…”

“…The clinical implication is that complexing proteins are immunogenic and can elicit an immune reaction against BoNT/A [67]. However, antibody titers required to cause resistance to botulinum toxin have not been defined and immune responses can differ between patients.…”

Di̇ş Heki̇mli̇ği̇nde Botoks: Derleme

“…Tüm serotipler aynı mekanizma ile etki etmektedir ancak farklı zehirleme etkileri vardır. En etkili olan ve en çok kullanılan ise Tip A (BTX-A)"dır 2,6,8,13,14 .…”

Botulinum toxin in the management of blepharospasm: current evidence and recent developments

“…The formulation of Botox ® was changed in 1997 to reduce the protein content to help reduce the formation of neutralizing antibodies. The host response to the neurotoxin-associated proteins might play an important role in local and systemic side effects, and the presence of these proteins seems to modulate the immune response [Wang et al 2014]. As mentioned above, Xeomin ® 's lack of complexing proteins is thought to make it less likely to cause neutralizing antibodies [Kanovsky et al 2011].…”