Abstract
Huwentoxin-IV (HwTx-IV) is a gating modifier peptide toxin from spiders that has weak affinity for the lipid bilayer. As some gating modifier toxins have affinity for model lipid bilayers, a tripartite relationship among gating modifier toxins, voltage-gated ion channels, and the lipid membrane surrounding the channels has been proposed. We previously designed an HwTx-IV analogue (gHwTx-IV) with reduced negative charge and increased hydrophobic surface profile, which displays increased lipid bilayer affinity and in vitro activity at the voltage-gated sodium channel subtype 1.7 (NaV1.7), a channel targeted in pain management. Here, we show that replacements of the positively-charged residues that contribute to the activity of the peptide can improve gHwTx-IV's potency and selectivity for NaV1.7. Using HwTx-IV, gHwTx-IV, [R26A]gHwTx-IV, [K27A]gHwTx-IV, and [R29A]gHwTx-IV variants, we examined their potency and selectivity at human NaV1.7 and their affinity for the lipid bilayer. [R26A]gHwTx-IV consistently displayed the most improved potency and selectivity for NaV1.7, examined alongside off-target NaVs, compared with HwTx-IV and gHwTx-IV. The lipid affinity of each of the three novel analogues was weaker than that of gHwTx-IV, but stronger than that of HwTx-IV, suggesting a possible relationship between in vitro potency at NaV1.7 and affinity for lipid bilayers. In a murine NaV1.7 engagement model, [R26A]gHwTx-IV exhibited an efficacy comparable with that of native HwTx-IV. In summary, this study reports the development of an HwTx-IV analogue with improved in vitro selectivity for the pain target NaV1.7 and with an in vivo efficacy similar to that of native HwTx-IV.
Original language | English |
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Pages (from-to) | 5067-5080 |
Number of pages | 14 |
Journal | Journal of Biological Chemistry |
Volume | 295 |
Issue number | 15 |
Early online date | 5 Mar 2020 |
DOIs | |
Publication status | Published - 10 Apr 2020 |
Bibliographical note
Funding Information:This work was supported by Australian National Health and Medical Research Council (NMHRC) Project Grant APP1080405 (to C. I. S.), Australian Research Council Future Fellow supported by ARC Grant FT160100055, ARC Australian Laureate Fellow supported by Australian Research Council Grant FL150100146, NHMRC Early Career Fellowship Grant APP1139961 (to J. R. D.), University of Queensland International Research Scholarships (to A. J. A., P. T., and H. N. T. T.), Australian Government Research Training Program Scholarships (to K. L. M., A. M., and M. R. I.), and by NHMRC Career Development Fellowship APP1162503 (to I. V.) The authors declare that they have no conflicts of interest with the contents of this article. The con-tent is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Publisher Copyright:
© 2020 American Society for Biochemistry and Molecular Biology Inc.. All rights reserved.
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology