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Goineau S, Gallet L, Froget G. Whole-Cell Configuration of the Patch-Clamp Technique in the hERG Channel Assay. Curr Protoc 2024; 4:e959. [PMID: 38334240 DOI: 10.1002/cpz1.959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
In vitro electrophysiological safety studies have become an integral part of the drug development process because, in many instances, compound-induced QT prolongation has been associated with a direct block of human ether-a-go-go-related gene (hERG) potassium channels or their native current, the rapidly activating delayed rectifier potassium current (IKr ). Therefore, according to the ICH S7B guideline, the in vitro hERG channel patch-clamp assay is commonly used as an early screen to predict the ability of a compound to prolong the QT interval prior to first-in-human testing. The protocols described in this article are designed to assess the effects of acute or long-term exposure to new chemical entities on the amplitude of IKr in HEK293 cells stably transfected with the hERG channel (whole-cell configuration of the patch-clamp technique). Examples of results obtained with moxifloxacin, terfenadine, arsenic, pentamidine, erythromycin, and sotalol are provided for illustrative purposes. © 2024 Wiley Periodicals LLC. Basic Protocol: Measurement of the acute effects of test items in the hERG channel test Alternate Protocol: Measurement of the long-term effects of test items in the hERG channel test.
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Affiliation(s)
- Sonia Goineau
- Porsolt Research Center, Le Genest-Saint-Isle, France
| | - Lucie Gallet
- Porsolt Research Center, Le Genest-Saint-Isle, France
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Zünkler BJ, Wos-Maganga M, Bohnet S, Kleinau A, Manns D, Chatterjee S. Intracellular Binding of Terfenadine Competes with Its Access to Pancreatic ß-cell ATP-Sensitive K + Channels and Human ether-à-go-go-Related Gene Channels. J Membr Biol 2023; 256:63-77. [PMID: 35763054 PMCID: PMC9884252 DOI: 10.1007/s00232-022-00252-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 06/02/2022] [Indexed: 02/07/2023]
Abstract
Most blockers of both hERG (human ether-à-go-go-related gene) channels and pancreatic ß-cell ATP-sensitive K+ (KATP) channels access their binding sites from the cytoplasmic side of the plasma membrane. It is unknown whether binding to intracellular components competes with binding of these substances to K+ channels. The whole-cell configuration of the patch-clamp technique, a laser-scanning confocal microscope, and fluorescence correlation spectroscopy (FCS) were used to study hERG channels expressed in HEK (human embryonic kidney) 293 cells and KATP channels from the clonal insulinoma cell line RINm5F. When applied via the pipette solution in the whole-cell configuration, terfenadine blocked both hERG and KATP currents with much lower potency than after application via the bath solution, which was not due to P-glycoprotein-mediated efflux of terfenadine. Such a difference was not observed with dofetilide and tolbutamide. 37-68% of hERG/EGFP (enhanced green-fluorescent protein) fusion proteins expressed in HEK 293 cells were slowly diffusible as determined by laser-scanning microscopy in the whole-cell configuration and by FCS in intact cells. Bath application of a green-fluorescent sulphonylurea derivative (Bodipy-glibenclamide) induced a diffuse fluorescence in the cytosol of RINm5F cells under whole-cell patch-clamp conditions. These observations demonstrate the presence of intracellular binding sites for hERG and KATP channel blockers not dialyzable by the patch-pipette solution. Intracellular binding of terfenadine was not influenced by a mutated hERG (Y652A) channel. In conclusion, substances with high lipophilicity are not freely diffusible inside the cell but steep concentration gradients might exist within the cell and in the sub-membrane space.
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Affiliation(s)
- Bernd J Zünkler
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany.
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106, Braunschweig, Germany.
| | - Maria Wos-Maganga
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
| | - Stefanie Bohnet
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
| | - Anne Kleinau
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
| | - Detlef Manns
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
| | - Shivani Chatterjee
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
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Tran PN, Sheng J, Randolph AL, Baron CA, Thiebaud N, Ren M, Wu M, Johannesen L, Volpe DA, Patel D, Blinova K, Strauss DG, Wu WW. Mechanisms of QT prolongation by buprenorphine cannot be explained by direct hERG channel block. PLoS One 2020; 15:e0241362. [PMID: 33157550 PMCID: PMC7647070 DOI: 10.1371/journal.pone.0241362] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 10/13/2020] [Indexed: 12/04/2022] Open
Abstract
Buprenorphine is a μ-opioid receptor (MOR) partial agonist used to manage pain and addiction. QTC prolongation that crosses the 10 msec threshold of regulatory concern was observed at a supratherapeutic dose in two thorough QT studies for the transdermal buprenorphine product BUTRANS®. Because QTC prolongation can be associated with Torsades de Pointes (TdP), a rare but potentially fatal ventricular arrhythmia, these results have led to further investigation of the electrophysiological effects of buprenorphine. Drug-induced QTC prolongation and TdP are most commonly caused by acute inhibition of hERG current (IhERG) that contribute to the repolarizing phase of the ventricular action potentials (APs). Concomitant inhibition of inward late Na+ (INaL) and/or L-type Ca2+ (ICaL) current can offer some protection against proarrhythmia. Therefore, we characterized the effects of buprenorphine and its major metabolite norbuprenorphine on cardiac hERG, Ca2+, and Na+ ion channels, as well as cardiac APs. For comparison, methadone, a MOR agonist associated with QTC prolongation and high TdP risk, and naltrexone and naloxone, two opioid receptor antagonists, were also studied. Whole cell recordings were performed at 37°C on cells stably expressing hERG, CaV1.2, and NaV1.5 proteins. Microelectrode array (MEA) recordings were made on human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). The results showed that buprenorphine, norbuprenorphine, naltrexone, and naloxone had no effect on IhERG, ICaL, INaL, and peak Na+ current (INaP) at clinically relevant concentrations. In contrast, methadone inhibited IhERG, ICaL, and INaL. Experiments on iPSC-CMs showed a lack of effect for buprenorphine, norbuprenorphine, naltrexone, and naloxone, and delayed repolarization for methadone at clinically relevant concentrations. The mechanism of QTC prolongation is opioid moiety-specific. This remains undefined for buprenorphine, while for methadone it involves direct hERG channel block. There is no evidence that buprenorphine use is associated with TdP. Whether this lack of TdP risk can be generalized to other drugs with QTC prolongation not mediated by acute hERG channel block warrants further study.
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Affiliation(s)
- Phu N. Tran
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
- Division of Immunology and Hematology Devices, Center for Devices and Radiological Health, US Food and Drug Administration. Silver Spring, Maryland, United States of America
| | - Jiansong Sheng
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
- CiPALab, Gaithersburg, Maryland, United States of America
| | - Aaron L. Randolph
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Claudia Alvarez Baron
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Nicolas Thiebaud
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
- Vertex Pharmaceuticals (Europe) Ltd, Abingdon, Oxfordshire, United Kingdom
| | - Ming Ren
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Min Wu
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
- Division of Immunology and Hematology Devices, Center for Devices and Radiological Health, US Food and Drug Administration. Silver Spring, Maryland, United States of America
| | - Lars Johannesen
- Division of Cardiology and Nephrology, Office of Cardiology, Hematology, Endocrinology and Nephrology, Office of New Drugs, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Donna A. Volpe
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Dakshesh Patel
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland, United States of America
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ksenia Blinova
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - David G. Strauss
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Wendy W. Wu
- Division of Applied Regulatory Science, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, United States of America
- * E-mail:
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Goineau S, Castagné V. Complementarity of in vitro and in vivo models for the evaluation of gastro-protective effects of pharmacological substances. Fundam Clin Pharmacol 2016; 31:155-164. [PMID: 27739140 DOI: 10.1111/fcp.12248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 09/28/2016] [Accepted: 10/11/2016] [Indexed: 11/29/2022]
Abstract
Gastric mucosa is frequently exposed to various gastric irritants, and there is a continuing requirement to develop new gastro-protective agents. This study compares the effects of three such agents, sucralfate, rebamipide, and cimetidine in both in vivo and in vitro indomethacin-induced gastric damage models. For the in vivo approach, rats were orally administered sucralfate, rebamipide, and cimetidine at 300 mg/kg before an acute dose of indomethacin (30 mg/kg). Gastric lesions were then macroscopically examined. For the in vitro approach, gastric mucosal cells were incubated with sucralfate (3 and 5 mg/mL), rebamipide (0.3 and 1 mm), and cimetidine (10 and 50 μg/mL) before exposure to indomethacin (3.8 mm). The release of lactate dehydrogenase (LDH) and mitochondrial function were then measured. Sucralfate, rebamipide, and cimetidine displayed gastro-protective effects in vivo (decreased number of gastric ulcers: -50% P < 0.05, -22% NS, and -69% P < 0.05, respectively, and reduced length of gastric lesions: -62% P < 0.05, -29% NS, and -70% P < 0.001, respectively). Cell damage induced by indomethacin in vitro was inhibited by sucralfate (LDH release) and by rebamipide and cimetidine (mitochondrial function and LDH release). In contrast, sucralfate accentuated the indomethacin-induced decrease in mitochondrial function. Although cultured gastric cells offer a promising tool for evaluating the cytotoxic or protective effects of test compounds, data from in vivo models are still needed to confirm in vitro data. Using both approaches provides more comprehensive insight into the effects of test compounds on the gastric mucosa.
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Affiliation(s)
- Sonia Goineau
- Porsolt S.A.S., Z.A. de Glatigné, 53940, Le Genest-Saint-Isle, France
| | - Vincent Castagné
- Porsolt S.A.S., Z.A. de Glatigné, 53940, Le Genest-Saint-Isle, France
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Kang J, Luo Y, Searles M, Rampe D. Observations on conducting whole-cell patch clamping of the hERG cardiac K + channel in pure human serum. J Appl Toxicol 2016; 37:445-453. [PMID: 27553911 DOI: 10.1002/jat.3377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 07/06/2016] [Accepted: 07/22/2016] [Indexed: 01/01/2023]
Abstract
Inhibition of the human ether-a-go-go-related gene (hERG) K+ channel by drugs leads to QT prolongation on the electrocardiogram and can result in serious cardiac arrhythmia. For this reason, screening of drugs on hERG is mandatory during the drug development process. Patch clamp electrophysiology in a defined physiological saline solution (PSS) represents the standard method for assaying drug effects on the channel. To make the assay more translatable to clinical studies, we have conducted whole-cell patch clamping of hERG using pure human serum as the extracellular medium. Pure human serum had little effect on the hERG channel waveform or the current-voltage relationship when compared to PSS. hERG current recordings were highly stable in serum at room temperature, but prolonged recordings at the physiological temperature required prior heat inactivation of the serum. Compared to PSS, the IC50 values, conducted at room temperature, of the classic hERG blocking drugs cisapride, moxifloxacin, and terfenadine were shifted to the right by an extent predicted by their known plasma protein binding, but we did not detect any differences in IC50 s between male and female serum. Total plasma levels of these drugs associated with clinical QT prolongation corresponded to small (<15%) inhibition of hERG current in pure serum suggesting that minor inhibition of the channel leads to observable pharmacodynamic effects. Conducting whole-cell patch clamping of hERG in human serum has the potential to make the assay more translatable to clinical studies and improve its predictive value for safety testing. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Jiesheng Kang
- Departments of Disposition, Safety, and Animal Research Sanofi, Inc., Waltham, Massachusetts, USA
| | - Yongyi Luo
- Departments of Disposition, Safety, and Animal Research Sanofi, Inc., Waltham, Massachusetts, USA
| | - Michelle Searles
- Departments of Disposition, Safety, and Animal Research Sanofi, Inc., Framingham, Massachusetts, USA
| | - David Rampe
- Departments of Disposition, Safety, and Animal Research Sanofi, Inc., Bridgewater, New Jersey, USA
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