Spider Peptide Toxin HwTx-IV Engineered to Bind to Lipid Membranes Has an Increased Inhibitory Potency at Human Voltage-Gated Sodium Channel hNa V 1.7

Biochim Biophys Acta Biomembr. 2017 May;1859(5):835-844. doi: 10.1016/j.bbamem.2017.01.020. Epub 2017 Jan 20.

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.

Keywords: Drug design; Gating modifier toxin; Huwentoxin; Pain therapeutic; Peptide-membrane interactions; Venom peptide.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 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
  • Spider Venoms / pharmacology*
  • Surface Plasmon Resonance

Substances

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