Direct evidence for high affinity blockade of Nav1.6 channel subtype by huwentoxin-IV spider peptide, using multiscale functional approaches

Tânia C. Gonçalves (1) , Rachid Boukaiba (1) , Jordi Molgó (2, 3) , Muriel Amar (2, 3) , Michel Partiseti (1) , Denis Servent (2, 3) , Evelyne Benoit (4, 2, 3)

1 Sanofi-Aventis R&D
2 SIMoS - Service d'Ingénierie Moléculaire pour la Santé (ex SIMOPRO)
3 MTS - Médicaments et Technologies pour la Santé
4 NeuroPSI - Institut des Neurosciences Paris-Saclay

The Chinese bird spider huwentoxin-IV (HwTx-IV) is well-known to be a highly potent blocker of NaV1.7 subtype of voltage-gated sodium (NaV) channels, a genetically validated analgesic target, and thus promising as a potential lead molecule for the development of novel pain therapeutics. In the present study, the interaction between HwTx-IV and NaV1.6 channel subtype was investigated using multiscale (from in vivo to individual cell) functional approaches. HwTx-IV was approximatively 2 times more efficient than tetrodotoxin (TTX) to inhibit the compound muscle action potential recorded from the mouse skeletal neuromuscular system in vivo, and 30 times more effective to inhibit nerve-evoked than directly-elicited muscle contractile force of isolated mouse hemidiaphragms. These results strongly suggest that the inhibition of nerve-evoked skeletal muscle functioning, produced by HwTx-IV, resulted from a toxin-induced preferential blockade of NaV1.6, compared to NaV1.4, channel subtype. This was confirmed by whole-cell automated patch-clamp experiments performed on human embryonic kidney (HEK)-293 cells overexpressing hNaV1.1-1.8 channel subtypes. HwTx-IV was also approximatively 850 times more efficient to inhibit TTX-sensitive than TTX-resistant sodium currents recorded from mouse dorsal root ganglia neurons. Finally, based on our data, we predict that blockade of the NaV1.6 channel subtype was involved in the in vivo toxicity of HwTx-IV, although this toxicity was more than 2 times lower than that of TTX. In conclusion, our results provide detailed information regarding the effects of HwTx-IV and allow a better understanding of the side-effect mechanisms involved in vivo and of channel subtype interactions resulting from the toxin activity.

Mots clés: Na(V) channel subtypes; Voltage-gated sodium channels; Mouse neuromuscular excitability; Mouse dorsal root ganglia neurons; Cell lines overexpressing Na(V) channel subtypes; Electrophysiology; Huwentoxin-IV

Domaines: Neurobiologie; Pharmacologie

Tânia C. Gonçalves, Rachid Boukaiba, Jordi Molgó, Muriel Amar, Michel Partiseti, et al.. Direct evidence for high affinity blockade of Nav1.6 channel subtype by huwentoxin-IV spider peptide, using multiscale functional approaches. Neuropharmacology, 2018, 133, pp.404-414. ⟨10.1016/j.neuropharm.2018.02.016⟩. ⟨hal-01828943⟩