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Rapid characterisation of hERG channel kinetics II: temperature dependence

Lei, Chon Lok; Clerx, Michael; Beattie, Kylie A.; Melgari, Dario; Hancox, Jules C.; Gavaghan, David J.; Polonchuk, Liudmila; Wang, Ken; Mirams, Gary R.

Rapid characterisation of hERG channel kinetics II: temperature dependence Thumbnail


Authors

Chon Lok Lei

Michael Clerx

Kylie A. Beattie

Dario Melgari

Jules C. Hancox

David J. Gavaghan

Liudmila Polonchuk

Ken Wang



Abstract

Ion channel behavior can depend strongly on temperature, with faster kinetics at physiological temperatures leading to considerable changes in currents relative to room temperature. These temperature-dependent changes in voltage-dependent ion channel kinetics (rates of opening, closing, inactivating, and recovery) are commonly represented with Q10 coefficients or an Eyring relationship. In this article, we assess the validity of these representations by characterizing channel kinetics at multiple temperatures. We focus on the human Ether-à-go-go-Related Gene (hERG) channel, which is important in drug safety assessment and commonly screened at room temperature so that results require extrapolation to physiological temperature. In Part I of this study, we established a reliable method for high-throughput characterization of hERG1a (Kv11.1) kinetics, using a 15-second information-rich optimized protocol. In this Part II, we use this protocol to study the temperature dependence of hERG kinetics using Chinese hamster ovary cells overexpressing hERG1a on the Nanion SyncroPatch 384PE, a 384-well automated patch-clamp platform, with temperature control. We characterize the temperature dependence of hERG gating by fitting the parameters of a mathematical model of hERG kinetics to data obtained at five distinct temperatures between 25 and 37°C and validate the models using different protocols. Our models reveal that activation is far more temperature sensitive than inactivation, and we observe that the temperature dependency of the kinetic parameters is not represented well by Q10 coefficients; it broadly follows a generalized, but not the standardly-used, Eyring relationship. We also demonstrate that experimental estimations of Q10 coefficients are protocol dependent. Our results show that a direct fit using our 15-s protocol best represents hERG kinetics at any given temperature and suggests that using the Generalized Eyring theory is preferable if no experimental data are available to derive model parameters at a given temperature.

Citation

Lei, C. L., Clerx, M., Beattie, K. A., Melgari, D., Hancox, J. C., Gavaghan, D. J., …Mirams, G. R. (2019). Rapid characterisation of hERG channel kinetics II: temperature dependence. Biophysical Journal, 117(12), 2455-2470. https://doi.org/10.1101/609719

Journal Article Type Article
Acceptance Date Jul 17, 2019
Online Publication Date Jul 25, 2020
Publication Date Dec 17, 2019
Deposit Date Jul 19, 2019
Publicly Available Date Mar 28, 2024
Print ISSN 0006-3495
Publisher Biophysical Society
Peer Reviewed Peer Reviewed
Volume 117
Issue 12
Pages 2455-2470
DOI https://doi.org/10.1101/609719
Public URL https://nottingham-repository.worktribe.com/output/1881721
Publisher URL https://www.sciencedirect.com/science/article/pii/S0006349519305983

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