title: 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.affiliation: Institute for Molecular Bioscience, The University of Queensland, Qld 4072, Australia.
authors.forename: Akello J
authors.initials: AJ
authors.lastname: Agwa
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Qld 4072, Australia.
authors.forename: Nicole
authors.initials: N
authors.lastname: Lawrence
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Qld 4072, Australia; School of Chemistry and Molecular Biosciences, The University of Queensland, Qld 4072, Australia.
authors.forename: Evelyne
authors.initials: E
authors.lastname: Deplazes
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Qld 4072, Australia.
authors.forename: Olivier
authors.initials: O
authors.lastname: Cheneval
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Qld 4072, Australia.
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Chen
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Qld 4072, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Craik
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Qld 4072, Australia. Electronic address: c.schroeder@imb.uq.edu.au.
authors.forename: Christina I
authors.initials: CI
authors.lastname: Schroeder
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Qld 4072, Australia. Electronic address: s.henriques@uq.edu.au.
authors.forename: Sónia T
authors.initials: ST
authors.lastname: Henriques
mesh_terms: D055592:Biophysical Phenomena; D006801:Humans; D008051:Lipid Bilayers / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D062556:NAV1.7 Voltage-Gated Sodium Channel / Q000187:drug effects*; D026941:Sodium Channel Blockers / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence; D013111:Spider Venoms / Q000378:metabolism / Q000494:pharmacology*; D020349:Surface Plasmon Resonance
chemical_list: D008051:Lipid Bilayers; D062556:NAV1.7 Voltage-Gated Sodium Channel; C486866:SCN9A protein, human; D026941:Sodium Channel Blockers; D013111:Spider Venoms; C470632:huwentoxin IV, Selenocosmia huwena
keywords: Drug design; Gating modifier toxin; Huwentoxin; Pain therapeutic; Peptide-membrane interactions; Venom peptide