Spider peptide toxin HwTx-IV engineered to bind to lipid membranes has an increased inhibitory potency at human voltage-gated sodium channel hNaV1.7.

Abstract

The human voltage-gated sodium channel sub-type 1.7 (hNaV1.7) is emerging as an attractive target for the development of potent and sub-type selective novel analgesics with increased potency and fewer side effects than existing therapeutics. HwTx-IV, a spider derived peptide toxin, inhibits hNaV1.7 with high potency and is therefore of great interest as an analgesic lead. In the current study we examined whether engineering a HwTx-IV analogue with increased ability to bind to lipid membranes would improve its inhibitory potency at hNaV1.7. This hypothesis was explored by comparing HwTx-IV and two analogues [E1PyrE]HwTx-IV (mHwTx-IV) and [E1G,E4G,F6W,Y30W]HwTx-IV (gHwTx-IV) on their membrane-binding affinity and hNaV1.7 inhibitory potency using a range of biophysical techniques including computational analysis, NMR spectroscopy, surface plasmon resonance, and fluorescence spectroscopy. HwTx-IV and mHwTx-IV exhibited weak affinity for lipid membranes, whereas gHwTx-IV showed improved affinity for the model membranes studied. In addition, activity assays using SH-SY5Y neuroblastoma cells expressing hNaV1.7 showed that gHwTx-IV has increased activity at hNaV1.7 compared to HwTx-IV. Based on these results we hypothesize that an increase in the affinity of HwTx-IV for lipid membranes is accompanied by improved inhibitory potency at hNaV1.7 and that increasing the affinity of gating modifier toxins to lipid bilayers is a strategy that may be useful for improving their potency at hNaV1.7.

• Authors: Akello J Agwa, Nicole Lawrence, Evelyne Deplazes, Olivier Cheneval, Rachel M Chen, David J Craik, Christina I Schroeder, Sónia T Henriques
• Journal: Biochimica et biophysica acta. Biomembranes (Biochim Biophys Acta Biomembr) Vol. 1859 Issue 5 Pg. 835-844 (May 2017) ISSN: 0005-2736 [Print] Netherlands
• PMID: 28115115 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2017 Elsevier B.V. All rights reserved.

Chemical References

• Lipid Bilayers
• NAV1.7 Voltage-Gated Sodium Channel
• SCN9A protein, human
• Sodium Channel Blockers
• Spider Venoms
• huwentoxin IV, Selenocosmia huwena

Topics

• Biophysical Phenomena
• Humans
• Lipid Bilayers (metabolism)
• Magnetic Resonance Spectroscopy
• NAV1.7 Voltage-Gated Sodium Channel (drug effects)
• Sodium Channel Blockers (pharmacology)
• Spectrometry, Fluorescence
• Spider Venoms (metabolism, pharmacology)
• Surface Plasmon Resonance