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Robinson GI, Li D, Wang B, Rahman T, Gerasymchuk M, Hudson D, Kovalchuk O, Kovalchuk I. Psilocybin and Eugenol Reduce Inflammation in Human 3D EpiIntestinal Tissue. Life (Basel) 2023; 13:2345. [PMID: 38137946 PMCID: PMC10744792 DOI: 10.3390/life13122345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/09/2023] [Accepted: 12/13/2023] [Indexed: 12/24/2023] Open
Abstract
Inflammation plays a pivotal role in the development and progression of inflammatory bowel disease (IBD), by contributing to tissue damage and exacerbating the immune response. The investigation of serotonin receptor 2A (5-HT2A) ligands and transient receptor potential (TRP) channel ligands is of significant interest due to their potential to modulate key inflammatory pathways, mitigate the pathological effects of inflammation, and offer new avenues for therapeutic interventions in IBD. This study investigates the anti-inflammatory effects of 5-HT2A ligands, including psilocybin, 4-AcO-DMT, and ketanserin, in combination with TRP channel ligands, including capsaicin, curcumin, and eugenol, on the inflammatory response induced by tumor necrosis factor (TNF)-α and interferon (IFN)-γ in human 3D EpiIntestinal tissue. Enzyme-linked immunosorbent assay was used to assess the expression of pro-inflammatory markers TNF-α, IFN-γ, IL-6, IL-8, MCP-1, and GM-CSF. Our results show that psilocybin, 4-AcO-DMT, and eugenol significantly reduce TNF-α and IFN-γ levels, while capsaicin and curcumin decrease these markers to a lesser extent. Psilocybin effectively lowers IL-6 and IL-8 levels, but curcumin, capsaicin, and 4-AcO-DMT have limited effects on these markers. In addition, psilocybin can significantly decrease MCP-1 and GM-CSF levels. While ketanserin lowers IL-6 and GM-CSF levels, there are no effects seen on TNF-α, IFN-γ, IL-8, or MCP-1. Although synergistic effects between 5-HT2A and TRP channel ligands are minimal in this study, the results provide further evidence of the anti-inflammatory effects of psilocybin and eugenol. Further research is needed to understand the mechanisms of action and the feasibility of using these compounds as anti-inflammatory therapies for conditions like IBD.
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Affiliation(s)
- Gregory Ian Robinson
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Dongping Li
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Bo Wang
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Tahiat Rahman
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Marta Gerasymchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Darryl Hudson
- GoodCap Pharmaceuticals, 520 3rd Avenue SW, Suite 1900, Calgary, AB T2P 0R3, Canada
| | - Olga Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Igor Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
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Robinson GI, Li D, Wang B, Zahoruiko Y, Gerasymchuk M, Hudson D, Kovalchuk O, Kovalchuk I. Anti-Inflammatory Effects of Serotonin Receptor and Transient Receptor Potential Channel Ligands in Human Small Intestinal Epithelial Cells. Curr Issues Mol Biol 2023; 45:6743-6774. [PMID: 37623246 PMCID: PMC10453699 DOI: 10.3390/cimb45080427] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 08/09/2023] [Accepted: 08/11/2023] [Indexed: 08/26/2023] Open
Abstract
Intestinal inflammation and dysbiosis can lead to inflammatory bowel diseases (IBD) and systemic inflammation, affecting multiple organs. Developing novel anti-inflammatory therapeutics is crucial for preventing IBD progression. Serotonin receptor type 2A (5-HT2A) ligands, including psilocybin (Psi), 4-Acetoxy-N,N-dimethyltryptamine (4-AcO-DMT), and ketanserin (Ket), along with transient receptor potential (TRP) channel ligands like capsaicin (Cap), curcumin (Cur), and eugenol (Eug), show promise as anti-inflammatory agents. In this study, we investigated the cytotoxic and anti-inflammatory effects of Psi, 4-AcO-DMT, Ket, Cap, Cur, and Eug on human small intestinal epithelial cells (HSEIC). HSEIC were exposed to tumor necrosis factor (TNF)-α and interferon (IFN)-γ for 24 h to induce an inflammatory response, followed by treatment with each compound at varying doses (0-800 μM) for 24 to 96 h. The cytotoxicity was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and protein expression by Western blot (WB) analysis. As single treatments, Psi (40 μM), Cur (0.5 μM), and Eug (50 μM) significantly reduced COX-2 levels without cytotoxic effects. When combined, Psi (40 μM) and Cur (0.5 μM) exhibited synergy, resulting in a substantial decrease in COX-2 protein levels (-28× fold change), although the reduction in IL-6 was less pronounced (-1.6× fold change). Psi (20 μM) and Eug (25 μM) demonstrated the most favorable outcomes, with significant decreases in COX-2 (-19× fold change) and IL-6 (-10× fold change) protein levels. Moreover, the combination of Psi and Eug did not induce cytotoxic effects in vitro at any tested doses. This study is the first to explore the anti-inflammatory potential of psilocybin and 4-AcO-DMT in the intestines while highlighting the potential for synergy between the 5-HT2A and TRP channel ligands, specifically Psi and Eug, in alleviating the TNF-α/IFN-γ-induced inflammatory response in HSEIC. Further investigations should evaluate if the Psi and Eug combination has the therapeutic potential to treat IBD in vivo.
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Affiliation(s)
- Gregory Ian Robinson
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada; (G.I.R.); (M.G.)
| | - Dongping Li
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada; (G.I.R.); (M.G.)
| | - Bo Wang
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada; (G.I.R.); (M.G.)
| | - Yeva Zahoruiko
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada; (G.I.R.); (M.G.)
| | - Marta Gerasymchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada; (G.I.R.); (M.G.)
| | - Darryl Hudson
- GoodCap Pharmaceuticals, Calgary, AB T2P 0R3, Canada
| | - Olga Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada; (G.I.R.); (M.G.)
| | - Igor Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada; (G.I.R.); (M.G.)
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Molecular Determinants for the High-Affinity Blockade of Human Ether-à-go-go-Related Gene K + Channel by Tolterodine. J Cardiovasc Pharmacol 2022; 80:679-689. [PMID: 35881423 DOI: 10.1097/fjc.0000000000001336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 07/03/2022] [Indexed: 02/04/2023]
Abstract
ABSTRACT Tolterodine is a first-line antimuscarinic drug used to treat overactive bladder. Adverse cardiac effects including tachycardia and palpitations have been observed, presumably because of its inhibition of the human ether-à-go-go-related gene (hERG) K + channel. However, the molecular mechanism of hERG channel inhibition by tolterodine is largely unclear. In this study, we performed molecular docking to identify potential binding sites of tolterodine in hERG channel, and two-microelectrode voltage-clamp to record the currents of hERG and its mutants expressed in Xenopus oocytes. The results of computational modeling demonstrated that phenylalanine at position 656 (F656) and tyrosine at position 652 (Y652) on the S6 helix of hERG channel are the most favorable binding residues of tolterodine, which was validated by electrophysiological recordings on Y652A and F656A hERG mutants. The Y652A and F656A mutations decreased inhibitory potency of tolterodine 345-fold and 126-fold, respectively. The Y652A mutation significantly altered the voltage dependence of channel inhibition by tolterodine. For both the wild-type and the mutant channels, tolterodine reduced the currents in a time-dependent manner, and the blockade occurred with the channel activated. Tolterodine did not interfere with hERG channel deactivation, whereas channel inactivation greatly impaired its blocking effect. The inhibition of hERG channel by tolterodine is independent of its action on muscarinic acetylcholine receptors. In conclusion, tolterodine is an open-state blocker of hERG K + channel with nanomolar potency. Y652 and F656, 2 aromatic residues on the inner S6 helix, are responsible for the high-affinity binding of tolterodine to hERG channel.
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Kubacka M, Kazek G, Kotańska M, Filipek B, Waszkielewicz AM, Mogilski S. Anti-aggregation effect of aroxyalkyl derivatives of 2-methoxyphenylpiperazine is due to their 5-HT2A and α2-adrenoceptor antagonistic properties. A comparison with ketanserin, sarpogrelate, prazosin, yohimbine and ARC239. Eur J Pharmacol 2018; 818:263-270. [DOI: 10.1016/j.ejphar.2017.10.053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 10/19/2017] [Accepted: 10/26/2017] [Indexed: 12/16/2022]
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Jeevaratnam K, Chadda KR, Huang CLH, Camm AJ. Cardiac Potassium Channels: Physiological Insights for Targeted Therapy. J Cardiovasc Pharmacol Ther 2017; 23:119-129. [PMID: 28946759 PMCID: PMC5808825 DOI: 10.1177/1074248417729880] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The development of novel drugs specifically directed at the ion channels underlying particular features of cardiac action potential (AP) initiation, recovery, and refractoriness would contribute to an optimized approach to antiarrhythmic therapy that minimizes potential cardiac and extracardiac toxicity. Of these, K+ channels contribute numerous and diverse currents with specific actions on different phases in the time course of AP repolarization. These features and their site-specific distribution make particular K+ channel types attractive therapeutic targets for the development of pharmacological agents attempting antiarrhythmic therapy in conditions such as atrial fibrillation. However, progress in the development of such temporally and spatially selective antiarrhythmic drugs against particular ion channels has been relatively limited, particularly in view of our incomplete understanding of the complex physiological roles and interactions of the various ionic currents. This review summarizes the physiological properties of the main cardiac potassium channels and the way in which they modulate cardiac electrical activity and then critiques a number of available potential antiarrhythmic drugs directed at them.
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Affiliation(s)
- Kamalan Jeevaratnam
- 1 Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,2 School of Medicine, Perdana University-Royal College of Surgeons Ireland, Serdang, Selangor Darul Ehsan, Malaysia
| | - Karan R Chadda
- 1 Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,3 Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Christopher L-H Huang
- 3 Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom.,4 Division of Cardiovascular Biology, Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - A John Camm
- 5 Cardiac Clinical Academic Group, St George's Hospital Medical School, University of London, Cranmer Terrace, London, United Kingdom
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Jie LJ, Wu WY, Li G, Xiao GS, Zhang S, Li GR, Wang Y. Clemizole hydrochloride blocks cardiac potassium currents stably expressed in HEK 293 cells. Br J Pharmacol 2017; 174:254-266. [PMID: 27886373 DOI: 10.1111/bph.13679] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 11/21/2016] [Accepted: 11/22/2016] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND AND PURPOSE Clemizole, a histamine H1 receptor antagonist has a potential therapeutic effect on hepatitis C infection and also potently inhibits TRPC5 ion channels. The aim of the present study was to investigate whether clemizole blocks cardiac K+ currents and thus affects cardiac repolarization. EXPERIMENTAL APPROACH Whole-cell patch techniques was used to examine the effects of clemizole on hERG channel current, IKs and Kv 1.5 channel current in HEK 293 cell expression systems as well as on ventricular action potentials of guinea pig hearts. Isolated hearts from guinea pigs were used to determine the effect on the ECG. KEY RESULTS Clemizole decreased hERG current by blocking both open and closed states of the channel in a concentration-dependent manner (IC50 : 0.07 μM). The S631A, S636A, Y652A and F656V hERG mutant channels reduced the inhibitory effect of clemizole (IC50 : 0.82, 0.89, 1.49 and 2.98 μM, respectively), suggesting that clemizole is a pore blocker of hERG channels. Clemizole also moderately decreased IKs and human Kv 1.5 channel current. Moreover, clemizole increased the duration of the ventricular action potential in guinea pig hearts and the QTc interval in isolated perfused hearts from guinea pigs, in a concentration-dependent manner (0.1-1.0 μM). CONCLUSION AND IMPLICATIONS Our results provide the first evidence that clemizole potently blocks hERG channels, moderately inhibits cardiac IKs , delays cardiac repolarization and thereby prolongs QT interval. Thus, caution should be taken when clemizole is used as a TRPC5 channel blocker or for treating hepatitis C infection.
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Affiliation(s)
- Ling-Jun Jie
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, China
| | - Wei-Yin Wu
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, China
| | - Gang Li
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, China
| | - Guo-Sheng Xiao
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, China
| | - Shetuan Zhang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Canada
| | - Gui-Rong Li
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, China
| | - Yan Wang
- Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, China
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Inhibitory effects of hesperetin on Kv1.5 potassium channels stably expressed in HEK 293 cells and ultra-rapid delayed rectifier K + current in human atrial myocytes. Eur J Pharmacol 2016; 789:98-108. [DOI: 10.1016/j.ejphar.2016.07.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 06/29/2016] [Accepted: 07/07/2016] [Indexed: 12/16/2022]
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Effects of neferine on Kv4.3 channels expressed in HEK293 cells and ex vivo electrophysiology of rabbit hearts. Acta Pharmacol Sin 2015; 36:1451-61. [PMID: 26592512 DOI: 10.1038/aps.2015.83] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 08/26/2015] [Indexed: 01/16/2023] Open
Abstract
AIM Neferine is an isoquinoline alkaloid isolated from seed embryos of Nelumbo nucifera (Gaertn), which has a variety of biological activities. In this study we examined the effects of neferine on Kv4.3 channels, a major contributor to the transient outward current (I(to)) in rabbit heart, and on ex vivo electrophysiology of rabbit hearts. METHODS Whole-cell Kv4.3 currents were recorded in HEK293 cells expressing human cardiac Kv4.3 channels using patch-clamp technique. Arterially perfused wedges of rabbit left ventricles (LV) were prepared, and transmembrane action potentials were simultaneously recorded from epicardial (Epi) and endocardial (Endo) sites with floating microelectrodes together with transmural electrocardiography (ECG). RESULTS Neferine (0.1-100 μmol/L) dose-dependently and reversibly inhibited Kv4.3 currents (the IC50 value was 8.437 μmol/L, and the maximal inhibition at 100 μmol/L was 44.12%). Neferine (10 μmol/L) caused a positive shift of the steady-state activation curve of Kv4.3 currents, and a negative shift of the steady-state inactivation curve. Furthermore, neferine (10 μmol/L) accelerated the inactivation but not the activation of Kv4.3 currents, and markedly slowed the recovery of Kv4.3 currents from inactivation. Neferine-induced blocking of Kv4.3 currents was frequency-dependent. In arterially perfused wedges of rabbit LV, neferine (1, 3, and 10 μmol/L) dose-dependently prolonged the QT intervals and action potential durations (APD) at both Epi and Endo sites, and caused dramatic increase of APD10 at Epi sites. CONCLUSION Neferine inhibits Kv4.3 channels likely by blocking the open state and inactivating state channels, which contributes to neferine-induced dramatic increase of APD10 at Epi sites of rabbit heart.
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Gualdani R, Tadini-Buoninsegni F, Roselli M, Defrenza I, Contino M, Colabufo NA, Lentini G. Inhibition of hERG potassium channel by the antiarrhythmic agent mexiletine and its metabolite m-hydroxymexiletine. Pharmacol Res Perspect 2015; 3:e00160. [PMID: 26516576 PMCID: PMC4618635 DOI: 10.1002/prp2.160] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 06/04/2015] [Indexed: 02/05/2023] Open
Abstract
Mexiletine is a sodium channel blocker, primarily used in the treatment of ventricular arrhythmias. Moreover, recent studies have demonstrated its therapeutic value to treat myotonic syndromes and to relieve neuropathic pain. The present study aims at investigating the direct blockade of hERG potassium channel by mexiletine and its metabolite m-hydroxymexiletine (MHM). Our data show that mexiletine inhibits hERG in a time- and voltage-dependent manner, with an IC50 of 3.7 ± 0.7 μmol/L. Analysis of the initial onset of current inhibition during a depolarizing test pulse indicates mexiletine binds preferentially to the open state of the hERG channel. Looking for a possible mexiletine alternative, we show that m-hydroxymexiletine (MHM), a minor mexiletine metabolite recently reported to be as active as the parent compound in an arrhythmia animal model, is a weaker hERG channel blocker, compared to mexiletine (IC50 = 22.4 ± 1.2 μmol/L). The hERG aromatic residues located in the S6 helix (Tyr652 and Phe656) are crucial in the binding of mexiletine and the different affinities of mexiletine and MHM with hERG channel are interpreted by modeling their corresponding binding interactions through ab initio calculations. The simulations demonstrate that the introduction of a hydroxyl group on the meta-position of the aromatic portion of mexiletine weakens the interaction of the drug xylyloxy moiety with Tyr652. These results provide further insights into the molecular basis of drug/hERG interactions and, in agreement with previously reported results on clofilium and ibutilide analogs, support the possibility of reducing hERG potency and related toxicity by modifying the aromatic pattern of substitution of clinically relevant compounds.
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Affiliation(s)
- Roberta Gualdani
- Dipartimento di Chimica "Ugo Schiff", Università di Firenze via della Lastruccia 3, Sesto Fiorentino, FI, 50019, Italy
| | - Francesco Tadini-Buoninsegni
- Dipartimento di Chimica "Ugo Schiff", Università di Firenze via della Lastruccia 3, Sesto Fiorentino, FI, 50019, Italy
| | - Mariagrazia Roselli
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari "A. Moro" via Orabona 4, Bari, 70125, Italy
| | - Ivana Defrenza
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari "A. Moro" via Orabona 4, Bari, 70125, Italy
| | - Marialessandra Contino
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari "A. Moro" via Orabona 4, Bari, 70125, Italy
| | - Nicola Antonio Colabufo
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari "A. Moro" via Orabona 4, Bari, 70125, Italy
| | - Giovanni Lentini
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari "A. Moro" via Orabona 4, Bari, 70125, Italy
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Design and bio-evaluation of indole derivatives as potent Kv1.5 inhibitors. Bioorg Med Chem 2013; 21:6466-76. [DOI: 10.1016/j.bmc.2013.08.041] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Revised: 08/21/2013] [Accepted: 08/22/2013] [Indexed: 01/29/2023]
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Wen D, Liu A, Chen F, Yang J, Dai R. Validation of visualized transgenic zebrafish as a high throughput model to assay bradycardia related cardio toxicity risk candidates. J Appl Toxicol 2012; 32:834-42. [PMID: 22744888 DOI: 10.1002/jat.2755] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 02/27/2012] [Accepted: 02/27/2012] [Indexed: 11/09/2022]
Abstract
Drug-induced QT prolongation usually leads to torsade de pointes (TdP), thus for drugs in the early phase of development this risk should be evaluated. In the present study, we demonstrated a visualized transgenic zebrafish as an in vivo high-throughput model to assay the risk of drug-induced QT prolongation. Zebrafish larvae 48 h post-fertilization expressing green fluorescent protein in myocardium were incubated with compounds reported to induce QT prolongation or block the human ether-a-go-go-related gene (hERG) K⁺ current. The compounds sotalol, indapaminde, erythromycin, ofoxacin, levofloxacin, sparfloxacin and roxithromycin were additionally administrated by microinjection into the larvae yolk sac. The ventricle heart rate was recorded using the automatic monitoring system after incubation or microinjection. As a result, 14 out of 16 compounds inducing dog QT prolongation caused bradycardia in zebrafish. A similar result was observed with 21 out of 26 compounds which block hERG current. Among the 30 compounds which induced human QT prolongation, 25 caused bradycardia in this model. Thus, the risk of compounds causing bradycardia in this transgenic zebrafish correlated with that causing QT prolongation and hERG K⁺ current blockage in established models. The tendency that high logP values lead to high risk of QT prolongation in this model was indicated, and non-sensitivity of this model to antibacterial agents was revealed. These data suggest application of this transgenic zebrafish as a high-throughput model to screen QT prolongation-related cardio toxicity of the drug candidates.
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Affiliation(s)
- Dingsheng Wen
- South China University of Technology, Guangzhou 510641, China
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Zhao J, Lian Y, Lu C, Jing L, Yuan H, Peng S. Inhibitory effects of a bisbenzylisoquinline alkaloid dauricine on HERG potassium channels. JOURNAL OF ETHNOPHARMACOLOGY 2012; 141:685-691. [PMID: 21920426 DOI: 10.1016/j.jep.2011.08.054] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 08/14/2011] [Accepted: 08/25/2011] [Indexed: 05/31/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The roots of Menispermum dauricum have been widely used for the treatment of inflammation, allergy and arrhythmia in China for a long time. Dauricine (Dau), a bisbenzylisoquinline alkaloid from Menispermum dauricum, mainly contributes to the anti-arrhythmic effect and has received pharmacological attention. Dau can prolong the action potential duration (APD), which has been attributed to its ability to modulate Ca(2+) and several K(+) channels. However, its effects on human-ether-a-go-go-related gene (HERG) channels are unknown. AIM OF THE STUDY The effects of Dau on HERG channels were investigated. MATERIALS AND METHODS Whole-cell patch-clamp technique was used to record HERG current (I(HERG)) carried by recombinant HERG channels expressed in HEK293 cells. RESULTS Dau inhibited I(HERG) in a concentration-dependent manner with an IC(50) of 3.5 μM. Development of block and washout were fast. The inhibitory action of Dau was contingent on channel gating, showing significant voltage and time dependence. Dau inhibited I(HERG) in the open and inactivated states, but not in the closed states. The activation curve was shifted in a negative direction. CONCLUSIONS Dau inhibits HERG encoded potassium channels and this action might be a molecular mechanism for the previously reported APD prolongation with this drug.
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Affiliation(s)
- Jing Zhao
- Evaluation and Research Centre for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Fengtai District, Beijing, PR China.
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Liu Y, Xu XH, Liu Z, Du XL, Chen KH, Xin X, Jin ZD, Shen JZ, Hu Y, Li GR, Jin MW. Effects of the natural flavone trimethylapigenin on cardiac potassium currents. Biochem Pharmacol 2012; 84:498-506. [PMID: 22583923 DOI: 10.1016/j.bcp.2012.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 04/30/2012] [Accepted: 05/01/2012] [Indexed: 11/17/2022]
Abstract
The natural flavones and polymethylflavone have been reported to have cardiovascular protective effects. In the present study, we determined whether quecertin, apigenin and their methylated compounds (3,7,3',4'-tetramethylquecertin, 3,5,7,3',4'-pentamethylquecertin, 7,4'-dimethylapigenin, and 5,7,4'-trimethylapigenin) would block the atrial specific potassium channel hKv1.5 using a whole-cell patch voltage-clamp technique. We found that only trimethylapigenin showed a strong inhibitory effect on hKv1.5 channel current. This compound suppressed hKv1.5 current in HEK 293 cell line (IC₅₀=6.4 μM), and the ultra-rapid delayed rectify K⁺ current I(Kur) in human atrial myocytes (IC₅₀=8.0 μM) by binding to the open channels and showed a use- and frequency-dependent manner. In addition, trimethylapigenin decreased transient outward potassium current (I(to)) in human atrial myocytes, inhibited acetylcholine-activated K⁺ current (IC₅₀=6.8μM) in rat atrial myocytes. Interestingly, trimethylapigenin had a weak inhibition of hERG channel current. Our results indicate that trimethyapigenin significantly inhibits the atrial potassium currents hKv1.5/I(Kur) and I(KACh), which suggests that trimethylapigenin may be a potential candidate for anti-atrial fibrillation.
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Affiliation(s)
- Yi Liu
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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Zhou Y, Wu HJ, Zhang YH, Sun HY, Wong TM, Li GR. Ionic mechanisms underlying cardiac toxicity of the organochloride solvent trichloromethane. Toxicology 2011; 290:295-304. [DOI: 10.1016/j.tox.2011.10.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Revised: 10/12/2011] [Accepted: 10/12/2011] [Indexed: 11/30/2022]
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Wu HJ, Wu W, Sun HY, Qin GW, Wang HB, Wang P, Yalamanchili HK, Wang J, Tse HF, Lau CP, Vanhoutte PM, Li GR. Acacetin causes a frequency- and use-dependent blockade of hKv1.5 channels by binding to the S6 domain. J Mol Cell Cardiol 2011; 51:966-73. [PMID: 21906601 DOI: 10.1016/j.yjmcc.2011.08.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 08/01/2011] [Accepted: 08/21/2011] [Indexed: 11/18/2022]
Abstract
We have demonstrated that the natural flavone acacetin selectively inhibits ultra-rapid delayed rectifier potassium current (I(Kur)) in human atria. However, molecular determinants of this ion channel blocker are unknown. The present study was designed to investigate the molecular determinants underlying the ability of acacetin to block hKv1.5 channels (coding I(Kur)) in human atrial myocytes using the whole-cell patch voltage-clamp technique to record membrane current in HEK 293 cells stably expressing the hKv1.5 gene or transiently expressing mutant hKv1.5 genes generated by site-directed mutagenesis. It was found that acacetin blocked hKv1.5 channels by binding to both closed and open channels. The blockade of hKv1.5 channels by acacetin was use- and frequency-dependent, and the IC(50) of acacetin for inhibiting hKv1.5 was 3.5, 3.1, 2.9, 2.1, and 1.7μM, respectively, at 0.2, 0.5, 1, 3, and 4Hz. The mutagenesis study showed that the hKv1.5 mutants V505A, I508A, and V512A in the S6-segment remarkably reduced the channel blocking properties by acacetin (IC(50), 29.5μM for V505A, 19.1μM for I508A, and 6.9μM for V512A). These results demonstrate the novel information that acacetin mainly blocks open hKv1.5 channels by binding to their S6 domain. The use- and rate-dependent blocking of hKv1.5 by acacetin is beneficial for anti-atrial fibrillation.
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Affiliation(s)
- Hui-Jun Wu
- Department and Medicine, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Pokfulam, Hong Kong SAR, China
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Zhang XH, Jin MW, Sun HY, Zhang S, Li GR. The calmodulin inhibitor N-(6-aminohexyl)-5-chloro-1-naphthalene sulphonamide directly blocks human ether à-go-go-related gene potassium channels stably expressed in human embryonic kidney 293 cells. Br J Pharmacol 2010; 161:872-84. [PMID: 20860665 DOI: 10.1111/j.1476-5381.2010.00916.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE N-(6-aminohexyl)-5-chloro-1-naphthalene sulphonamide (W-7) is a well-known calmodulin inhibitor used to study calmodulin regulation of intracellular Ca(2+) signalling-related process. Here, we have determined whether W-7 would inhibit human ether gene (hERG or K(v) 11.1) potassium channels, hK(v) 1.5 channels or hK(IR) 2.1 channels expressed in human embryonic kidney (HEK) 293 cells. EXPERIMENTAL APPROACH The hERG channel current, hK(v) 1.5 channel current or hK(IR) 2.1 channel current was recorded with a whole-cell patch clamp technique. KEY RESULTS It was found that the calmodulin inhibitor W-7 blocked hERG, hK(v) 1.5 and hK(IR) 2.1 channels. W-7 decreased the hERG current (I(hERG) ) in a concentration-dependent manner (IC(50) : 3.5 µM), and the inhibition was more significant at depolarization potentials between +10 and +60 mV. The hERG mutations in the S6 region Y652A and F656V, and in the pore helix S631A, had the IC(50) s of 5.5, 9.8 and 25.4 µM respectively. In addition, the compound inhibited hK(v) 1.5 and hK(IR) 2.1 channels with IC(50) s of 6.5 and 13.4 µM respectively. CONCLUSION AND IMPLICATIONS These results indicate that the calmodulin inhibitor W-7 exerts a direct channel-blocking effect on hERG, hK(v) 1.5 and hK(IR) 2.1 channels stably expressed in HEK 293 cells. Caution should be taken in the interpretation of calmodulin regulation of ion channels with W-7.
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Affiliation(s)
- Xiao-Hua Zhang
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
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Li GR, Dong MQ. Pharmacology of Cardiac Potassium Channels. CARDIOVASCULAR PHARMACOLOGY - HEART AND CIRCULATION 2010; 59:93-134. [DOI: 10.1016/s1054-3589(10)59004-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Serotonin 5-HT(2A) Receptor Function as a Contributing Factor to Both Neuropsychiatric and Cardiovascular Diseases. Cardiovasc Psychiatry Neurol 2009; 2009:475108. [PMID: 20029624 PMCID: PMC2790184 DOI: 10.1155/2009/475108] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 08/07/2009] [Accepted: 08/14/2009] [Indexed: 12/19/2022] Open
Abstract
There are high levels of comorbidity between neuropsychiatric and cardiovascular disorders. A key molecule central to both cognitive and cardiovascular function is the molecule serotonin. In the brain, serotonin modulates neuronal activity and is actively involved in mediating many cognitive functions and behaviors. In the periphery, serotonin is involved in vasoconstriction, inflammation, and cell growth, among other processes. It is hypothesized that one component of the serotonin system, the 5-HT(2A) receptor, is a common and contributing factor underlying aspects of the comorbidity between neuropsychiatric and cardiovascular disorders. Within the brain this receptor participates in processes such as cognition and working memory, been implicated in effective disorders such as schizophrenia, and mediate the primary effects of hallucinogenic drugs. In the periphery, 5-HT(2A) receptors have been linked to vasoconstriction and hypertension, and to inflammatory processes that can lead to atherosclerosis.
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