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Asrani P, Seebohm G, Stoll R. From viruses to humans - Exploring the structure-function relationship of the Kesv protein for the future of biomedicine. J Struct Biol 2024; 216:108112. [PMID: 39069032 DOI: 10.1016/j.jsb.2024.108112] [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: 04/24/2024] [Revised: 07/12/2024] [Accepted: 07/26/2024] [Indexed: 07/30/2024]
Abstract
Viruses often use ion channel proteins to initialise host infections. Defects in ion channel proteins are also linked to several metabolic disorders in humans. In that instance, modulation of ion channel activities becomes central to development of antiviral therapies and drug design. Kesv, a potassium-selective ion channel protein expressed by Ectocarpus siliculosus virus (EsV), possesses remarkable properties which can help to characterise the molecular basis of the functional processes relevant to virus biology and human physiology. The small structural features of this ion channel could serve as a fundamental primer to study more complex ion channels from humans. Therefore, in spite of their evolutionary distance, the potential link between viral and human ion channel proteins could provide opportunities for therapeutic and biotechnological applications.
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Affiliation(s)
- Purva Asrani
- Biomolecular Spectroscopy and RUBiospec, NMR, Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Bochum D-44780, Germany
| | - Guiscard Seebohm
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital, Munster D-48149, Germany
| | - Raphael Stoll
- Biomolecular Spectroscopy and RUBiospec, NMR, Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Bochum D-44780, Germany.
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2
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Seck I, Ndoye SF, Kapchoup MVK, Nguemo F, Ciss I, Ba LA, Ba A, Sokhna S, Seck M. Effects of plant extracts and derivatives on cardiac K +, Nav, and Ca v channels: a review. Nat Prod Res 2024:1-28. [PMID: 38586947 DOI: 10.1080/14786419.2024.2337112] [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: 11/14/2023] [Accepted: 03/24/2024] [Indexed: 04/09/2024]
Abstract
Natural products (NPs) are endless sources of compounds for fighting against several pathologies. Many dysfunctions, including cardiovascular disorders, such as cardiac arrhythmias have their modes of action regulation of the concentration of electrolytes inside and outside the cell targeting ion channels. Here, we highlight plant extracts and secondary metabolites' effects on the treatment of related cardiac pathologies on hERG, Nav, and Cav of cardiomyocytes. The natural product's pharmacology of expressed receptors like alpha-adrenergic receptors causes an influx of Ca2+ ions through receptor-operated Ca2+ ion channels. We also examine the NPs associated with cardiac contractions such as myocardial contractility by reducing the L-type calcium current and decreasing the intracellular calcium transient, inhibiting the K+ induced contractions, decreasing amplitude of myocyte shortening and showed negative ionotropic and chronotropic effects due to decreasing cytosolic Ca2+. We examine whether the NPs block potassium channels, particular the hERG channel and regulatory effects on Nav1.7.
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Affiliation(s)
- Insa Seck
- Laboratoire de Chimie de Coordination Organique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Samba Fama Ndoye
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | | | - Filomain Nguemo
- Institute of Neurophysiology, University of Cologne, Cologne, Germany
| | - Ismaila Ciss
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Lalla Aicha Ba
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Abda Ba
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Seynabou Sokhna
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
| | - Matar Seck
- Laboratoire de Chimie Organique et Thérapeutique, Université Cheikh Anta Diop de Dakar, Dakar, Senegal
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3
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Dellin M, Rohrbeck I, Asrani P, Schreiber JA, Ritter N, Glorius F, Wünsch B, Budde T, Temme L, Strünker T, Stallmeyer B, Tüttelmann F, Meuth SG, Spehr M, Matschke J, Steinbicker A, Gatsogiannis C, Stoll R, Strutz-Seebohm N, Seebohm G. The second PI(3,5)P 2 binding site in the S0 helix of KCNQ1 stabilizes PIP 2-at the primary PI1 site with potential consequences on intermediate-to-open state transition. Biol Chem 2023; 404:241-254. [PMID: 36809224 DOI: 10.1515/hsz-2022-0247] [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] [Received: 08/05/2022] [Accepted: 12/13/2022] [Indexed: 02/23/2023]
Abstract
The Phosphatidylinositol 3-phosphate 5-kinase Type III PIKfyve is the main source for selectively generated phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2), a known regulator of membrane protein trafficking. PI(3,5)P2 facilitates the cardiac KCNQ1/KCNE1 channel plasma membrane abundance and therewith increases the macroscopic current amplitude. Functional-physical interaction of PI(3,5)P2 with membrane proteins and its structural impact is not sufficiently understood. This study aimed to identify molecular interaction sites and stimulatory mechanisms of the KCNQ1/KCNE1 channel via the PIKfyve-PI(3,5)P2 axis. Mutational scanning at the intracellular membrane leaflet and nuclear magnetic resonance (NMR) spectroscopy identified two PI(3,5)P2 binding sites, the known PIP2 site PS1 and the newly identified N-terminal α-helix S0 as relevant for functional PIKfyve effects. Cd2+ coordination to engineered cysteines and molecular modeling suggest that repositioning of S0 stabilizes the channel s open state, an effect strictly dependent on parallel binding of PI(3,5)P2 to both sites.
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Affiliation(s)
- Maurice Dellin
- IfGH-Cellular Electrophysiology, Department of Cardiology and Angiology, University Hospital of Münster, Robert-Koch Str. 45, D-48149, Münster, Germany
| | - Ina Rohrbeck
- IfGH-Cellular Electrophysiology, Department of Cardiology and Angiology, University Hospital of Münster, Robert-Koch Str. 45, D-48149, Münster, Germany
| | - Purva Asrani
- Faculty of Chemistry and Biochemistry, Biomolecular NMR Spectroscopy and RUBiospek|NMR, Ruhr University of Bochum, Universitätsstraße 150, D-44780, Bochum, Germany
| | - Julian A Schreiber
- IfGH-Cellular Electrophysiology, Department of Cardiology and Angiology, University Hospital of Münster, Robert-Koch Str. 45, D-48149, Münster, Germany
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149, Münster, Germany
| | - Nadine Ritter
- IfGH-Cellular Electrophysiology, Department of Cardiology and Angiology, University Hospital of Münster, Robert-Koch Str. 45, D-48149, Münster, Germany
- GRK 2515, Chemical biology of ion channels (Chembion), Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Frank Glorius
- GRK 2515, Chemical biology of ion channels (Chembion), Westfälische Wilhelms-Universität Münster, Münster, Germany
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, D-48149, Münster, Germany
| | - Bernhard Wünsch
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149, Münster, Germany
- GRK 2515, Chemical biology of ion channels (Chembion), Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Thomas Budde
- GRK 2515, Chemical biology of ion channels (Chembion), Westfälische Wilhelms-Universität Münster, Münster, Germany
- Institute of Physiology I, Westfälische Wilhelms-Universität, Robert-Koch-Str. 27a, D-48149, Münster, Germany
| | - Louisa Temme
- Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149, Münster, Germany
- GRK 2515, Chemical biology of ion channels (Chembion), Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Timo Strünker
- GRK 2515, Chemical biology of ion channels (Chembion), Westfälische Wilhelms-Universität Münster, Münster, Germany
- Centre of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Domagkstraße 11, D-48149, Münster, Germany
- Cells in Motion Interfaculty Centre, University of Münster, Münster, Germany
| | - Birgit Stallmeyer
- Institute of Reproductive Genetics, University of Münster, Vesaliusweg 12-14, D-48149, Münster, Germany
| | - Frank Tüttelmann
- Institute of Reproductive Genetics, University of Münster, Vesaliusweg 12-14, D-48149, Münster, Germany
| | - Sven G Meuth
- Department of Neurology, Heinrich Heine University Düsseldorf, Moorenstraße 5, D-40225, Düsseldorf, Germany
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Worringerweg 3, D-52074, Aachen, Germany
| | - Johann Matschke
- Institute of Cell Biology (Cancer Research), University Hospital Essen, University of Duisburg-Essen, D-45147, Essen, Germany
| | - Andrea Steinbicker
- Goethe University Frankfurt and University Hospital Frankfurt, Theodor-Stern-Kai 7, D-60590, Frankfurt, Germany
| | - Christos Gatsogiannis
- Institute for Medical Physics and Biophysics and Center for Soft Nanoscience, Westfälische Wilhelms-Universität Münster, Münster, Busso-Peus Strasse 10, D-48149, Germany
| | - Raphael Stoll
- Faculty of Chemistry and Biochemistry, Biomolecular NMR Spectroscopy and RUBiospek|NMR, Ruhr University of Bochum, Universitätsstraße 150, D-44780, Bochum, Germany
| | - Nathalie Strutz-Seebohm
- IfGH-Cellular Electrophysiology, Department of Cardiology and Angiology, University Hospital of Münster, Robert-Koch Str. 45, D-48149, Münster, Germany
| | - Guiscard Seebohm
- IfGH-Cellular Electrophysiology, Department of Cardiology and Angiology, University Hospital of Münster, Robert-Koch Str. 45, D-48149, Münster, Germany
- GRK 2515, Chemical biology of ion channels (Chembion), Westfälische Wilhelms-Universität Münster, Münster, Germany
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4
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Asrani P, Seebohm G, Stoll R. Potassium viroporins as model systems for understanding eukaryotic ion channel behaviour. Virus Res 2022; 320:198903. [PMID: 36037849 DOI: 10.1016/j.virusres.2022.198903] [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] [Received: 03/14/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 11/29/2022]
Abstract
Ion channels are membrane proteins essential for a plethora of cellular functions including maintaining cell shape, ion homeostasis, cardiac rhythm and action potential in neurons. The complexity and often extensive structure of eukaryotic membrane proteins makes it difficult to understand their basic biological regulation. Therefore, this article suggests, viroporins - the miniature versions of eukaryotic protein homologs from viruses - might serve as model systems to provide insights into behaviour of eukaryotic ion channels in general. The structural requirements for correct assembly of the channel along with the basic functional properties of a K+ channel exist in the minimal design of the viral K+ channels from two viruses, Chlorella virus (Kcv) and Ectocarpus siliculosus virus (Kesv). These small viral proteins readily assemble into tetramers and they sort in cells to distinct target membranes. When these viruses-encoded channels are expressed into the mammalian cells, they utilise their protein machinery and hence can serve as excellent tools to study the cells protein sorting machinery. This combination of small size and robust function makes viral K+ channels a valuable model system for detection of basic structure-function correlations. It is believed that molecular and physiochemical analyses of these viroporins may serve as basis for the development of inhibitors or modulators to ion channel activity for targeting ion channel diseases - so called channelopathies. Therefore, it may provide a potential different scope for molecular pharmacology studies aiming at novel and innovative therapeutics associated with channel related diseases. This article reviews the structural and functional properties of Kcv and Kesv upon expression in mammalian cells and Xenopus oocytes. The mechanisms behind differential protein sorting in Kcv and Kesv are also thoroughly discussed.
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Affiliation(s)
- Purva Asrani
- Biomolecular Spectroscopy and RUBiospec|NMR, Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Bochum D-44780, Germany
| | - Guiscard Seebohm
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Münster D-48149, Germany
| | - Raphael Stoll
- Biomolecular Spectroscopy and RUBiospec|NMR, Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Bochum D-44780, Germany.
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5
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Lübke M, Schreiber JA, Le Quoc T, Körber F, Müller J, Sivanathan S, Matschke V, Schubert J, Strutz‐Seebohm N, Seebohm G, Scherkenbeck J. Rottlerin: Structure Modifications and KCNQ1/KCNE1 Ion Channel Activity. ChemMedChem 2020; 15:1078-1088. [PMID: 32338831 PMCID: PMC7318133 DOI: 10.1002/cmdc.202000083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/20/2020] [Indexed: 11/10/2022]
Abstract
The slow delayed rectifier potassium current (IKs ) is formed by the KCNQ1 (Kv 7.1) channel, an ion channel of four α-subunits that modulates KCNE1 β-subunits. IKs is central to the repolarization of the cardiac action potential. Loss of function mutation reducing ventricular cardiac IKs cause the long-QT syndrome (LQTS), a disorder that predisposes patients to arrhythmia and sudden death. Current therapy for LQTS is inadequate. Rottlerin, a natural product of the kamala tree, activates IKs and has the potential to provide a new strategy for rational drug therapy. In this study, we show that simple modifications such as penta-acetylation or penta-methylation of rottlerin blunts activation activity. Total synthesis was used to prepare side-chain-modified derivatives that slowed down KCNQ1/KCNE1 channel deactivation to different degrees. A binding hypothesis of rottlerin is provided that opens the way to improved IKs activators as novel therapeutics for the treatment of LQTS.
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Affiliation(s)
- Marco Lübke
- Faculty of Mathematics and Natural SciencesUniversity Wuppertal42119WuppertalGermany
| | - Julian A. Schreiber
- Institut für Genetik von HerzerkrankungenUniversity Hospital MünsterAlbert-Schweitzer-Campus 148149MünsterGermany
| | - Thang Le Quoc
- Department of ChemistryHue University34 Le Loi St.Hue CityVietnam
| | - Florian Körber
- Faculty of Mathematics and Natural SciencesUniversity Wuppertal42119WuppertalGermany
| | - Jasmin Müller
- Faculty of Mathematics and Natural SciencesUniversity Wuppertal42119WuppertalGermany
| | | | - Veronika Matschke
- Medical Faculty, Institute of Anatomy Department of CytologyRuhr University Bochum44801BochumGermany
| | - Janina Schubert
- Institut für Genetik von HerzerkrankungenUniversity Hospital MünsterAlbert-Schweitzer-Campus 148149MünsterGermany
| | - Nathalie Strutz‐Seebohm
- Institut für Genetik von HerzerkrankungenUniversity Hospital MünsterAlbert-Schweitzer-Campus 148149MünsterGermany
| | - Guiscard Seebohm
- Institut für Genetik von HerzerkrankungenUniversity Hospital MünsterAlbert-Schweitzer-Campus 148149MünsterGermany
| | - Jürgen Scherkenbeck
- Faculty of Mathematics and Natural SciencesUniversity Wuppertal42119WuppertalGermany
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6
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Rezazadeh S, Duff H. Dissociative States: hERG Channel (Kv11.1) Modulators That Enhance Dissociation of Drugs From Their Blocking Receptor. Circ Arrhythm Electrophysiol 2016; 9:e004003. [DOI: 10.1161/circep.116.004003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Saman Rezazadeh
- From the Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Henry Duff
- From the Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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7
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Yang PC, Song Y, Giles WR, Horvath B, Chen-Izu Y, Belardinelli L, Rajamani S, Clancy CE. A computational modelling approach combined with cellular electrophysiology data provides insights into the therapeutic benefit of targeting the late Na+ current. J Physiol 2015; 593:1429-42. [PMID: 25545172 DOI: 10.1113/jphysiol.2014.279554] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 12/18/2014] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS The ventricular action potential plateau is a phase of high resistance, which makes ventricular myocytes vulnerable to small electrical perturbations. We developed a computationally based model of GS-458967 interaction with the cardiac Na+ channel, informed by experimental data recorded from guinea pig isolated single ventricular myocytes. The model predicts that the therapeutic potential of GS-458967 derives largely from the designed property of significant potent selectivity for INaL. ABSTRACT Selective inhibition of the slowly inactivating or late Na(+) current (INaL) in patients with inherited or acquired arrhythmia syndrome may confer therapeutic benefit by reducing the incidence of triggers for arrhythmia and suppressing one component of arrhythmia-promoting cardiac substrates (e.g. prolonged refractoriness and spatiotemporal dispersion of action potential duration). Recently, a novel compound that preferentially and potently reduces INaL, GS-458967 (IC50 for block of INaL = 130 nM) has been studied. Experimental measurements of the effects of GS-458967 on endogenous INaL in guinea pig ventricular myocytes demonstrate a robust concentration-dependent reduction in action potential duration (APD). Using experimental data to calibrate INaL and the rapidly activating delayed rectifier K(+) current, IKr, in the Faber-Rudy computationally based model of the guinea pig ventricular action potential, we simulated effects of GS-458967 on guinea pig ventricular APD. GS-458967 (0.1 μM) caused a 28.67% block of INaL and 12.57% APD shortening in experiments, while the model predicted 10.06% APD shortening with 29.33% block of INaL. An additional effect of INaL block is to reduce the time during which the membrane potential is in a high resistance state (i.e. the action potential plateau). To test the hypothesis that targeted block of INaL would make ventricular myocytes less susceptible to small electrical perturbations, we used the computational model to test the degree of APD prolongation induced by small electrical perturbations in normal cells and in cells with simulated long QT syndrome. The model predicted a substantial dose-dependent reduction in sensitivity to small electrical perturbations as evidenced by action potential duration at 90% repolarization variability in the presence of GS-458967-induced INaL block. This effect was especially potent in the 'disease setting' of inherited long QT syndrome. Using a combined experimental and theoretical approach, our results suggest that INaL block is a potent therapeutic strategy. This is because reduction of INaL stabilizes the action potential waveform by reducing depolarizing current during the plateau phase of the action potential. This reduces the most vulnerable phase of the action potential with high membrane resistance. In summary, by reducing the sensitivity of the myocardial substrate to small electrical perturbations that promote arrhythmia triggers, agents such as GS-458967 may constitute an effective antiarrhythmic pharmacological strategy.
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8
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Yu Z, van Veldhoven JPD, 't Hart IME, Kopf AH, Heitman LH, IJzerman AP. Synthesis and biological evaluation of negative allosteric modulators of the Kv11.1(hERG) channel. Eur J Med Chem 2015; 106:50-9. [PMID: 26519929 DOI: 10.1016/j.ejmech.2015.10.032] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 10/14/2015] [Accepted: 10/16/2015] [Indexed: 01/13/2023]
Abstract
We synthesized and evaluated a series of compounds for their allosteric modulation at the Kv11.1 (hERG) channel. Most compounds were negative allosteric modulators of [(3)H]dofetilide binding to the channel, in particular 7f, 7h-j and 7p. Compounds 7f and 7p were the most potent negative allosteric modulators amongst all ligands, significantly increasing the dissociation rate of dofetilide in the radioligand kinetic binding assay, while remarkably reducing the affinities of dofetilide and astemizole in a competitive displacement assay. Additionally, both 7f and 7p displayed peculiar displacement characteristics with Hill coefficients significantly distinct from unity as shown by e.g., dofetilide, further indicative of their allosteric effects on dofetilide binding. Our findings in this investigation yielded several promising negative allosteric modulators for future functional and clinical research with respect to their antiarrhythmic propensities, either alone or in combination with known Kv11.1 blockers.
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Affiliation(s)
- Zhiyi Yu
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Jacobus P D van Veldhoven
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Ingrid M E 't Hart
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Adrian H Kopf
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Laura H Heitman
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Adriaan P IJzerman
- Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands.
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9
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Kohl B, Rothenberg I, Ali SA, Alam M, Seebohm G, Kalbacher H, Voelter W, Stoll R. Solid phase synthesis, NMR structure determination of α-KTx3.8, its in silico docking to Kv1.x potassium channels, and electrophysiological analysis provide insights into toxin-channel selectivity. Toxicon 2015; 101:70-8. [PMID: 25953725 DOI: 10.1016/j.toxicon.2015.04.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 04/07/2015] [Accepted: 04/29/2015] [Indexed: 12/29/2022]
Abstract
Animal venoms, such as those from scorpions, are a potent source for new pharmacological substances. In this study we have determined the structure of the α-KTx3.8 (named as Bs6) scorpion toxin by multidimensional (1)H homonuclear NMR spectroscopy and investigated its function by molecular dynamics (MD) simulations and electrophysiological measurements. Bs6 is a potent inhibitor of the Kv1.3 channel which plays an important role during the activation and proliferation of memory T-cells (TEM), which play an important role in autoimmune diseases. Therefore, it could be an interesting target for treatment of autoimmune diseases. In this study, Bs6 was synthesised by solid phase synthesis and its three-dimensional (3D) structure has been determined. To gain a deeper insight into the interaction of Bs6 with different potassium channels like hKv1.1 and hKv1.3, the protein-protein complex was modelled based on known toxin-channel structures and tested for stability in MD simulations using GROMACS. The toxin-channel interaction was further analysed by electrophysiological measurements of different potassium channels like hKv1.3 and hKv7.1. As potassium channel inhibitors could play an important role to overcome autoimmune diseases like multiple sclerosis and type-1 diabetes mellitus, our data contributes to the understanding of the molecular mechanism of action and will ultimately help to develop new potent inhibitors in future.
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Affiliation(s)
- Bastian Kohl
- Ruhr University Bochum, Faculty of Chemistry and Biochemistry, Biomolecular Spectroscopy, Ruhr University of Bochum, D-44780 Bochum, Germany
| | - Ina Rothenberg
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, D-48149 Münster, Germany
| | - Syed Abid Ali
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen D-72076, Germany; HEJ Research Institute of Chemistry, ICCBS, University of Karachi, Karachi 75270, Pakistan
| | - Mehtab Alam
- Dow International College, Dow University of Health Sciences, Karachi 75270, Pakistan
| | - Guiscard Seebohm
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, D-48149 Münster, Germany
| | - Hubert Kalbacher
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen D-72076, Germany
| | - Wolfgang Voelter
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen D-72076, Germany.
| | - Raphael Stoll
- Ruhr University Bochum, Faculty of Chemistry and Biochemistry, Biomolecular Spectroscopy, Ruhr University of Bochum, D-44780 Bochum, Germany.
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10
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Wang Y, Yuan J, Qian Z, Zhang X, Chen Y, Hou X, Zou J. β2 adrenergic receptor activation governs cardiac repolarization and arrhythmogenesis in a guinea pig model of heart failure. Sci Rep 2015; 5:7681. [PMID: 25567365 PMCID: PMC4286790 DOI: 10.1038/srep07681] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 12/04/2014] [Indexed: 12/11/2022] Open
Abstract
β2-AR activation increases the risk of sudden cardiac death (SCD) in heart failure (HF) patients. Non-selective β-AR blockers have greater benefits on survival than selective β1-AR blockers in chronic HF patients, indicating that β2-AR activation contributes to SCD in HF. This study investigated the role of β2-AR activation on repolarization and ventricular arrhythmia (VA) in the experimental HF model. The guinea pig HF was induced by descending aortic banding. The effective refractoriness period (ERP), corrected QT (QTc) and the incidence of VA were examined using Langendorff and programmed electrical stimulation. Ikr and APD were recorded by the whole cell patch clamp. Selective β2-AR agonist salbutamol significantly increased the incidence of VA, prolonged QTc and shortened ERP. These effects could be prevented by the selective β2-AR antagonist, ICI118551. Salbutamol prolonged APD90 and reduced Ikr in guinea pig HF myocytes. The antagonists of cAMP (Rp-cAMP) and PKA (KT5720) attenuated Ikr inhibition and APD prolongation induced by salbutamol. However, the antagonists of Gi protein (PTX) and PDE III (amrinone) showed opposite effects. This study indicates that β2-AR activation increases the incidence of VA in the experimental HF model via activation of Gs/cAMP/PKA and/or inhibition of Gi/PDE pathways.
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Affiliation(s)
- Yao Wang
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jiamin Yuan
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Zhiyong Qian
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xiwen Zhang
- Department of Cardiology, Huai'an First People's Hospital Affiliated to Nanjing Medical University, Huai'an, Jiangsu, China
| | - Yanhong Chen
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xiaofeng Hou
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jiangang Zou
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
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11
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Guo J, Durdagi S, Changalov M, Perissinotti LL, Hargreaves JM, Back TG, Noskov SY, Duff HJ. Structure driven design of novel human ether-a-go-go-related-gene channel (hERG1) activators. PLoS One 2014; 9:e105553. [PMID: 25191697 PMCID: PMC4156305 DOI: 10.1371/journal.pone.0105553] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 07/22/2014] [Indexed: 01/01/2023] Open
Abstract
One of the main culprits in modern drug discovery is apparent cardiotoxicity of many lead-candidates via inadvertent pharmacologic blockade of K+, Ca2+ and Na+ currents. Many drugs inadvertently block hERG1 leading to an acquired form of the Long QT syndrome and potentially lethal polymorphic ventricular tachycardia. An emerging strategy is to rely on interventions with a drug that may proactively activate hERG1 channels reducing cardiovascular risks. Small molecules-activators have a great potential for co-therapies where the risk of hERG-related QT prolongation is significant and rehabilitation of the drug is impractical. Although a number of hERG1 activators have been identified in the last decade, their binding sites, functional moieties responsible for channel activation and thus mechanism of action, have yet to be established. Here, we present a proof-of-principle study that combines de-novo drug design, molecular modeling, chemical synthesis with whole cell electrophysiology and Action Potential (AP) recordings in fetal mouse ventricular myocytes to establish basic chemical principles required for efficient activator of hERG1 channel. In order to minimize the likelihood that these molecules would also block the hERG1 channel they were computationally engineered to minimize interactions with known intra-cavitary drug binding sites. The combination of experimental and theoretical studies led to identification of functional elements (functional groups, flexibility) underlying efficiency of hERG1 activators targeting binding pocket located in the S4–S5 linker, as well as identified potential side-effects in this promising line of drugs, which was associated with multi-channel targeting of the developed drugs.
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Affiliation(s)
- Jiqing Guo
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Serdar Durdagi
- Centre for Molecular Simulation, Biochemistry Research Cluster, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
- Department of Biophysics, School of Medicine, Bahcesehir University, Istanbul, Turkey
| | - Mohamed Changalov
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada
| | - Laura L. Perissinotti
- Centre for Molecular Simulation, Biochemistry Research Cluster, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | | | - Thomas G. Back
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada
- * E-mail: (TGB); (SYN); (HJD)
| | - Sergei Y. Noskov
- Centre for Molecular Simulation, Biochemistry Research Cluster, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
- * E-mail: (TGB); (SYN); (HJD)
| | - Henry J. Duff
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
- * E-mail: (TGB); (SYN); (HJD)
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Rampe D, Brown AM. A history of the role of the hERG channel in cardiac risk assessment. J Pharmacol Toxicol Methods 2013; 68:13-22. [DOI: 10.1016/j.vascn.2013.03.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 03/14/2013] [Accepted: 03/14/2013] [Indexed: 01/25/2023]
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13
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Subbotina J, Yarov-Yarovoy V, Lees-Miller J, Durdagi S, Guo J, Duff HJ, Noskov SY. Structural refinement of the hERG1 pore and voltage-sensing domains with ROSETTA-membrane and molecular dynamics simulations. Proteins 2010; 78:2922-34. [PMID: 20740484 PMCID: PMC2939218 DOI: 10.1002/prot.22815] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The hERG1 gene (Kv11.1) encodes a voltage-gated potassium channel. Mutations in this gene lead to one form of the Long QT Syndrome (LQTS) in humans. Promiscuous binding of drugs to hERG1 is known to alter the structure/function of the channel leading to an acquired form of the LQTS. Expectably, creation and validation of reliable 3D model of the channel have been a key target in molecular cardiology and pharmacology for the last decade. Although many models were built, they all were limited to pore domain. In this work, a full model of the hERG1 channel is developed which includes all transmembrane segments. We tested a template-driven de-novo design with ROSETTA-membrane modeling using side-chain placements optimized by subsequent molecular dynamics (MD) simulations. Although backbone templates for the homology modeled parts of the pore and voltage sensors were based on the available structures of KvAP, Kv1.2 and Kv1.2-Kv2.1 chimera channels, the missing parts are modeled de-novo. The impact of several alignments on the structure of the S4 helix in the voltage-sensing domain was also tested. Herein, final models are evaluated for consistency to the reported structural elements discovered mainly on the basis of mutagenesis and electrophysiology. These structural elements include salt bridges and close contacts in the voltage-sensor domain; and the topology of the extracellular S5-pore linker compared with that established by toxin foot-printing and nuclear magnetic resonance studies. Implications of the refined hERG1 model to binding of blockers and channels activators (potent new ligands for channel activations) are discussed.
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Affiliation(s)
- Julia Subbotina
- Institute for Biocomplexity and Informatics, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | | | - James Lees-Miller
- Libin Cardiovascular Institute of Alberta, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Serdar Durdagi
- Institute for Biocomplexity and Informatics, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Jiqing Guo
- Libin Cardiovascular Institute of Alberta, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Henry J. Duff
- Libin Cardiovascular Institute of Alberta, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Sergei Yu. Noskov
- Institute for Biocomplexity and Informatics, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
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14
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Gessner G, Macianskiene R, Starkus JG, Schönherr R, Heinemann SH. The amiodarone derivative KB130015 activates hERG1 potassium channels via a novel mechanism. Eur J Pharmacol 2010; 632:52-9. [PMID: 20097192 DOI: 10.1016/j.ejphar.2010.01.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 12/07/2009] [Accepted: 01/12/2010] [Indexed: 11/29/2022]
Abstract
Human ether à go-go related gene (hERG1) potassium channels underlie the repolarizing I(Kr) current in the heart. Since they are targets of various drugs with cardiac side effects we tested whether the amiodarone derivative 2-methyl-3-(3,5-diiodo-4-carboxymethoxybenzyl)benzofuran (KB130015) blocks hERG1 channels like its parent compound. Using patch-clamp and two-electrode voltage-clamp techniques we found that KB130015 blocks native and recombinant hERG1 channels at high voltages, but it activates them at low voltages. The activating effect has an apparent EC(50) value of 12microM and is brought about by an about 4-fold acceleration of activation kinetics and a shift in voltage-dependent activation by -16mV. Channel activation was not use-dependent and was independent of inactivation gating. KB130015 presumably binds to the hERG1 pore from the cytosolic side and functionally competes with hERG1 block by amiodarone, E4031 (N-[4-[[1-[2-(6-methyl-2-pyridinyl)ethyl]-4-piperidinyl] carbonyl] phenyl] methanesulfonamide dihydrochloride), and sertindole. Vice versa, amiodarone attenuates hERG1 activation by KB130015. Based on synergic channel activation by mallotoxin and KB130015 we conclude that the hERG1 pore contains at least two sites for activators that are functionally coupled among each other and to the cavity-blocker site. KB130015 and amiodarone may serve as lead structures for the identification of hERG1 pore-interacting drugs favoring channel activation vs. block.
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Affiliation(s)
- Guido Gessner
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University of Jena, Germany
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15
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Novel pharmacological approaches for antiarrhythmic therapy. Naunyn Schmiedebergs Arch Pharmacol 2010; 381:187-93. [DOI: 10.1007/s00210-009-0487-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Accepted: 12/17/2009] [Indexed: 01/14/2023]
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16
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Structure, function, and modification of the voltage sensor in voltage-gated ion channels. Cell Biochem Biophys 2008; 52:149-74. [PMID: 18989792 DOI: 10.1007/s12013-008-9032-5] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2008] [Indexed: 01/12/2023]
Abstract
Voltage-gated ion channels are crucial for both neuronal and cardiac excitability. Decades of research have begun to unravel the intriguing machinery behind voltage sensitivity. Although the details regarding the arrangement and movement in the voltage-sensor domain are still debated, consensus is slowly emerging. There are three competing conceptual models: the helical-screw, the transporter, and the paddle model. In this review we explore the structure of the activated voltage-sensor domain based on the recent X-ray structure of a chimera between Kv1.2 and Kv2.1. We also present a model for the closed state. From this we conclude that upon depolarization the voltage sensor S4 moves approximately 13 A outwards and rotates approximately 180 degrees, thus consistent with the helical-screw model. S4 also moves relative to S3b which is not consistent with the paddle model. One interesting feature of the voltage sensor is that it partially faces the lipid bilayer and therefore can interact both with the membrane itself and with physiological and pharmacological molecules reaching the channel from the membrane. This type of channel modulation is discussed together with other mechanisms for how voltage-sensitivity is modified. Small effects on voltage-sensitivity can have profound effects on excitability. Therefore, medical drugs designed to alter the voltage dependence offer an interesting way to regulate excitability.
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hERG: The long and short of it. Heart Rhythm 2008; 5:591-2. [DOI: 10.1016/j.hrthm.2008.02.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Indexed: 11/21/2022]
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18
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Gordon E, Lozinskaya IM, Lin Z, Semus SF, Blaney FE, Willette RN, Xu X. 2-[2-(3,4-Dichloro-phenyl)-2,3-dihydro-1H-isoindol-5-ylamino]-nicotinic Acid (PD-307243) Causes Instantaneous Current through HumanEther-a-go-go-Related Gene Potassium Channels. Mol Pharmacol 2007; 73:639-51. [DOI: 10.1124/mol.107.041152] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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19
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Stambler BS. Tachycardia-induced ventricular electrical remodeling: A perspective on unresolved experimental mechanisms and clinical implications. Heart Rhythm 2006; 3:1378-81. [PMID: 17074649 DOI: 10.1016/j.hrthm.2006.06.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2006] [Indexed: 11/23/2022]
Affiliation(s)
- Bruce S Stambler
- Division of Cardiology, Department of Medicine, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106, USA.
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20
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Wu DM, Lai LP, Zhang M, Wang HL, Jiang M, Liu XS, Tseng GN. Characterization of an LQT5-related mutation in KCNE1, Y81C: Implications for a role of KCNE1 cytoplasmic domain in IKs channel function. Heart Rhythm 2006; 3:1031-40. [PMID: 16945797 DOI: 10.1016/j.hrthm.2006.05.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Accepted: 05/18/2006] [Indexed: 11/17/2022]
Abstract
BACKGROUND Y81C is a new long QT-5 (LQT5)-related KCNE1 mutation, which is located in the post-transmembrane domain (post-TMD) region in close proximity to three other LQT5 mutations (S74L, D76N, and W87R). OBJECTIVE We examine the effects of Y81C on the function and drug sensitivity of the slow delayed rectifier channel (I(Ks)) formed by KCNE1 with pore-forming KCNQ1 subunits. We also infer a structural basis for the detrimental effects of Y81C on I(Ks) function. METHODS Wild-type (WT) and mutant (harboring Y81C) I(Ks) channels are expressed in oocytes or COS-7 cells. Channel function and KCNQ1 protein expression/subcellular distribution are studied by techniques of electrophysiology, biochemistry, and immunocytochemistry. Ab initio structure predictions of KCNE1 cytoplasmic domain are performed by the Robetta server. RESULTS Relative to WT KCNE1, Y81C reduces I(Ks) current amplitude and shifts the voltage range of activation to a more positive range. Y81C does not reduce whole-cell KCNQ1 protein level or interfere with KCNQ1 trafficking to cell surface. Thus, its effects are mediated by altered KCNQ1/KCNE1 interactions in cell surface channels. Importantly, Y81C potentiates the effects of an I(Ks) activator. Preserving the aromatic or hydroxyl side chain at position 81 (Y81F or Y81T) does not prevent the detrimental effects of Y81C. Structure predictions suggest that the post-TMD region of KCNE1 may adopt a helical secondary structure. CONCLUSION We propose that the post-TMD region of KCNE1 interacts with the KCNQ1 channel to modulate I(Ks) current amplitude and gating kinetics. Other LQT5 mutations in this region share the Y81C phenotype and probably affect the I(Ks) channel function by a similar mechanism.
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Affiliation(s)
- Dong-Mei Wu
- Department of Physiology, Virginia Commonwealth University, Richmond, 23298, USA
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