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Emigh Cortez AM, DeMarco KR, Furutani K, Bekker S, Sack JT, Wulff H, Clancy CE, Vorobyov I, Yarov-Yarovoy V. Structural modeling of hERG channel-drug interactions using Rosetta. Front Pharmacol 2023; 14:1244166. [PMID: 38035013 PMCID: PMC10682396 DOI: 10.3389/fphar.2023.1244166] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 10/23/2023] [Indexed: 12/02/2023] Open
Abstract
The human ether-a-go-go-related gene (hERG) not only encodes a potassium-selective voltage-gated ion channel essential for normal electrical activity in the heart but is also a major drug anti-target. Genetic hERG mutations and blockage of the channel pore by drugs can cause long QT syndrome, which predisposes individuals to potentially deadly arrhythmias. However, not all hERG-blocking drugs are proarrhythmic, and their differential affinities to discrete channel conformational states have been suggested to contribute to arrhythmogenicity. We used Rosetta electron density refinement and homology modeling to build structural models of open-state hERG channel wild-type and mutant variants (Y652A, F656A, and Y652A/F656 A) and a closed-state wild-type channel based on cryo-electron microscopy structures of hERG and EAG1 channels. These models were used as protein targets for molecular docking of charged and neutral forms of amiodarone, nifekalant, dofetilide, d/l-sotalol, flecainide, and moxifloxacin. We selected these drugs based on their different arrhythmogenic potentials and abilities to facilitate hERG current. Our docking studies and clustering provided atomistic structural insights into state-dependent drug-channel interactions that play a key role in differentiating safe and harmful hERG blockers and can explain hERG channel facilitation through drug interactions with its open-state hydrophobic pockets.
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Affiliation(s)
- Aiyana M. Emigh Cortez
- Biophysics Graduate Group, University of California, Davis, Davis, CA, United States
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
| | - Kevin R. DeMarco
- Biophysics Graduate Group, University of California, Davis, Davis, CA, United States
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
| | - Kazuharu Furutani
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
- Department of Pharmacology, Tokushima Bunri University, Tokushima, Japan
| | - Slava Bekker
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
- American River College, Sacramento, CA, United States
| | - Jon T. Sack
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
- Department of Anesthesiology and Pain Medicine, University of California, Davis, Davis, CA, United States
| | - Heike Wulff
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Colleen E. Clancy
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
- Center for Precision Medicine and Data Sciences, University of California, Davis, Davis, CA, United States
| | - Igor Vorobyov
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
- Department of Anesthesiology and Pain Medicine, University of California, Davis, Davis, CA, United States
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2
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Furutani K. Facilitation of hERG Activation by Its Blocker: A Mechanism to Reduce Drug-Induced Proarrhythmic Risk. Int J Mol Sci 2023; 24:16261. [PMID: 38003453 PMCID: PMC10671758 DOI: 10.3390/ijms242216261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 11/08/2023] [Accepted: 11/12/2023] [Indexed: 11/26/2023] Open
Abstract
Modulation of the human Ether-à-go-go-Related Gene (hERG) channel, a crucial voltage-gated potassium channel in the repolarization of action potentials in ventricular myocytes of the heart, has significant implications on cardiac electrophysiology and can be either antiarrhythmic or proarrhythmic. For example, hERG channel blockade is a leading cause of long QT syndrome and potentially life-threatening arrhythmias, such as torsades de pointes. Conversely, hERG channel blockade is the mechanism of action of Class III antiarrhythmic agents in terminating ventricular tachycardia and fibrillation. In recent years, it has been recognized that less proarrhythmic hERG blockers with clinical potential or Class III antiarrhythmic agents exhibit, in addition to their hERG-blocking activity, a second action that facilitates the voltage-dependent activation of the hERG channel. This facilitation is believed to reduce the proarrhythmic potential by supporting the final repolarizing of action potentials. This review covers the pharmacological characteristics of hERG blockers/facilitators, the molecular mechanisms underlying facilitation, and their clinical significance, as well as unresolved issues and requirements for research in the fields of ion channel pharmacology and drug-induced arrhythmias.
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Affiliation(s)
- Kazuharu Furutani
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, 180 Nishihama-Boji, Yamashiro-cho, Tokushima 770-8514, Japan
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3
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Maly J, Emigh AM, DeMarco KR, Furutani K, Sack JT, Clancy CE, Vorobyov I, Yarov-Yarovoy V. Structural modeling of the hERG potassium channel and associated drug interactions. Front Pharmacol 2022; 13:966463. [PMID: 36188564 PMCID: PMC9523588 DOI: 10.3389/fphar.2022.966463] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Accepted: 08/25/2022] [Indexed: 11/13/2022] Open
Abstract
The voltage-gated potassium channel, KV11.1, encoded by the human Ether-à-go-go-Related Gene (hERG), is expressed in cardiac myocytes, where it is crucial for the membrane repolarization of the action potential. Gating of the hERG channel is characterized by rapid, voltage-dependent, C-type inactivation, which blocks ion conduction and is suggested to involve constriction of the selectivity filter. Mutations S620T and S641A/T within the selectivity filter region of hERG have been shown to alter the voltage dependence of channel inactivation. Because hERG channel blockade is implicated in drug-induced arrhythmias associated with both the open and inactivated states, we used Rosetta to simulate the effects of hERG S620T and S641A/T mutations to elucidate conformational changes associated with hERG channel inactivation and differences in drug binding between the two states. Rosetta modeling of the S641A fast-inactivating mutation revealed a lateral shift of the F627 side chain in the selectivity filter into the central channel axis along the ion conduction pathway and the formation of four lateral fenestrations in the pore. Rosetta modeling of the non-inactivating mutations S620T and S641T suggested a potential molecular mechanism preventing F627 side chain from shifting into the ion conduction pathway during the proposed inactivation process. Furthermore, we used Rosetta docking to explore the binding mechanism of highly selective and potent hERG blockers - dofetilide, terfenadine, and E4031. Our structural modeling correlates well with much, but not all, existing experimental evidence involving interactions of hERG blockers with key residues in hERG pore and reveals potential molecular mechanisms of ligand interactions with hERG in an inactivated state.
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Affiliation(s)
- Jan Maly
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States,Biophysics Graduate Group, University of California, Davis, Davis, CA, United States
| | - Aiyana M. Emigh
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States,Biophysics Graduate Group, University of California, Davis, Davis, CA, United States
| | - Kevin R. DeMarco
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States,Biophysics Graduate Group, University of California, Davis, Davis, CA, United States
| | - Kazuharu Furutani
- Department of Pharmacology, Tokushima Bunri University, Tokushima, Japan
| | - Jon T. Sack
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
| | - Colleen E. Clancy
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States,Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Igor Vorobyov
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States,Department of Pharmacology, University of California, Davis, Davis, CA, United States,*Correspondence: Igor Vorobyov, ; Vladimir Yarov-Yarovoy,
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States,*Correspondence: Igor Vorobyov, ; Vladimir Yarov-Yarovoy,
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4
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Furutani K, Kawano R, Ichiwara M, Adachi R, Clancy CE, Sack JT, Kita S. Pore opening, not voltage sensor movement, underpins the voltage-dependence of facilitation by a hERG blocker. Mol Pharmacol 2022; 102:MOLPHARM-AR-2022-000569. [PMID: 36041862 PMCID: PMC9595204 DOI: 10.1124/molpharm.122.000569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 07/19/2022] [Accepted: 08/04/2022] [Indexed: 11/07/2022] Open
Abstract
A drug that blocks the cardiac myocyte voltage-gated K+ channels encoded by the human Ether-à-go-go-Related Gene (hERG) carries a potential risk of long QT syndrome and life-threatening cardiac arrhythmia, including Torsade de Points Interestingly, certain hERG blockers can also facilitate hERG activation to increase hERG currents, which may reduce proarrhythmic potential. However, the molecular mechanism involved in the facilitation effect of hERG blockers remains unclear. The hallmark feature of the facilitation effect by hERG blockers is that a depolarizing preconditioning pulse shifts voltage-dependence of hERG activation to more negative voltages. Here we utilize a D540K hERG mutant to study the mechanism of the facilitation effect. D540K hERG is activated by not only depolarization but also hyperpolarization. This unusual gating property enables tests of the mechanism by which voltage induces facilitation of hERG by blockers. With D540K hERG, we find that nifekalant, a hERG blocker and Class III antiarrhythmic agent, blocks and facilitates not only current activation by depolarization but also current activation by hyperpolarization, suggesting a shared gating process upon depolarization and hyperpolarization. Moreover, in response to hyperpolarizing conditioning pulses, nifekalant facilitates D540K hERG currents but not wild-type currents. Our results indicate that induction of facilitation is coupled to pore opening, not voltage per se We propose that gated access to the hERG central cavity underlies the voltage-dependence of induction of facilitation. This study identifies hERG channel pore gate opening as the conformational change facilitated by nifekalant, a clinically important antiarrhythmic agent. Significance Statement Nifekalant is a clinically important antiarrhythmic agent and a hERG blocker which can also facilitate voltage-dependent activation of hERG channels after a preconditioning pulse. Here we show that the mechanism of action of the preconditioning pulse is to open a conductance gate to enable drug access to a facilitation site. Moreover, we find that facilitation increases hERG currents by altering pore dynamics, rather than acting through voltage sensors.
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Affiliation(s)
| | - Ryotaro Kawano
- Department of Pharmacology, Tokushima Bunri University, Japan
| | - Minami Ichiwara
- Department of Pharmacology, Tokushima Bunri University, Japan
| | - Ryo Adachi
- Department of Pharmacology, Tokushima Bunri University, Japan
| | | | - Jon T Sack
- UC Davis School of Medicine, United States
| | - Satomi Kita
- Department of Pharmacology, Tokushima Bunri University, Japan
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5
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Emigh Cortez A, DeMarco K, Furutani K, Sack JT, Clancy CE, Vorobyov IV, Yarov-Yarovoy V. Predicting arrhythmogenicity: structural modeling of safe and unsafe hERG blockers using Rosetta. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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6
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DeMarco KR, Yang PC, Singh V, Furutani K, Dawson JRD, Jeng MT, Fettinger JC, Bekker S, Ngo VA, Noskov SY, Yarov-Yarovoy V, Sack JT, Wulff H, Clancy CE, Vorobyov I. Molecular determinants of pro-arrhythmia proclivity of d- and l-sotalol via a multi-scale modeling pipeline. J Mol Cell Cardiol 2021; 158:163-177. [PMID: 34062207 PMCID: PMC8906354 DOI: 10.1016/j.yjmcc.2021.05.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 05/03/2021] [Accepted: 05/24/2021] [Indexed: 11/20/2022]
Abstract
Drug isomers may differ in their proarrhythmia risk. An interesting example is the drug sotalol, an antiarrhythmic drug comprising d- and l- enantiomers that both block the hERG cardiac potassium channel and confer differing degrees of proarrhythmic risk. We developed a multi-scale in silico pipeline focusing on hERG channel – drug interactions and used it to probe and predict the mechanisms of pro-arrhythmia risks of the two enantiomers of sotalol. Molecular dynamics (MD) simulations predicted comparable hERG channel binding affinities for d- and l-sotalol, which were validated with electrophysiology experiments. MD derived thermodynamic and kinetic parameters were used to build multi-scale functional computational models of cardiac electrophysiology at the cell and tissue scales. Functional models were used to predict inactivated state binding affinities to recapitulate electrocardiogram (ECG) QT interval prolongation observed in clinical data. Our study demonstrates how modeling and simulation can be applied to predict drug effects from the atom to the rhythm for dl-sotalol and also increased proarrhythmia proclivity of d- vs. l-sotalol when accounting for stereospecific beta-adrenergic receptor blocking.
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Affiliation(s)
- Kevin R DeMarco
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA
| | - Pei-Chi Yang
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA
| | - Vikrant Singh
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Kazuharu Furutani
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA; Department of Pharmacology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Tokushima 770-8514, Japan
| | - John R D Dawson
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA; Biophysics Graduate Group, University of California Davis, Davis, CA 95616, USA
| | - Mao-Tsuen Jeng
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA
| | - James C Fettinger
- Department of Chemistry, University of California Davis, Davis, CA 95616, USA
| | - Slava Bekker
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA; Department of Science and Engineering, American River College, Sacramento, CA 95841, USA
| | - Van A Ngo
- Centre for Molecular Simulation and Biochemistry Research Cluster, Department of Biological Sciences, University of Calgary, Calgary, AB T2N1N4, Canada
| | - Sergei Y Noskov
- Centre for Molecular Simulation and Biochemistry Research Cluster, Department of Biological Sciences, University of Calgary, Calgary, AB T2N1N4, Canada
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA; Department of Anesthesiology and Pain Medicine, University of California Davis, Davis, CA 95616, USA
| | - Jon T Sack
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA; Department of Anesthesiology and Pain Medicine, University of California Davis, Davis, CA 95616, USA
| | - Heike Wulff
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Colleen E Clancy
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA; Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Igor Vorobyov
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA; Department of Pharmacology, University of California Davis, Davis, CA 95616, USA.
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7
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Emigh AM, DeMarco KR, Furutani K, Sack JT, Clancy CE, Vorobyov IV, Yarov-Yarovoy V. Predicting Arrhythmogenicity: Structural Modeling of Safe and Unsafe Herg Blockers. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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8
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DeMarco KR, Yang PC, Furutani K, Dawson JR, Bekker S, Ngo VA, Noskov SY, Yarov-Yarovoy V, Sack JT, Clancy CE, Vorobyov I. Molecular Determinants of D and L-Sotalol Stereoselective Proarrhythmia Procilivties. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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9
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Kodama M, Furutani K, Kimura R, Ando T, Sakamoto K, Nagamori S, Ashihara T, Kurachi Y, Sekino Y, Furukawa T, Kanda Y, Kurokawa J. Systematic expression analysis of genes related to generation of action potentials in human iPS cell-derived cardiomyocytes. J Pharmacol Sci 2019; 140:325-330. [DOI: 10.1016/j.jphs.2019.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 06/04/2019] [Accepted: 06/12/2019] [Indexed: 01/25/2023] Open
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10
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Uchida S, Asai Y, Kariya Y, Tsumoto K, Hibino H, Honma M, Abe T, Nin F, Kurata Y, Furutani K, Suzuki H, Kitano H, Inoue R, Kurachi Y. Integrative and theoretical research on the architecture of a biological system and its disorder. J Physiol Sci 2019; 69:433-451. [PMID: 30868372 PMCID: PMC6456489 DOI: 10.1007/s12576-019-00667-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/08/2019] [Indexed: 11/28/2022]
Abstract
An organism stems from assemblies of a variety of cells and proteins. This complex system serves as a unit, and it exhibits highly sophisticated functions in response to exogenous stimuli that change over time. The complete sequencing of the entire human genome has allowed researchers to address the enigmas of life and disease at the gene- or molecular-based level. The consequence of such studies is the rapid accumulation of a multitude of data at multiple levels, ranging from molecules to the whole body, that has necessitated the development of entirely new concepts, tools, and methodologies to analyze and integrate these data. This necessity has given birth to systems biology, an advanced theoretical and practical research framework that has totally changed the directions of not only basic life science but also medicine. During the symposium of the 95th Annual Meeting of The Physiological Society of Japan 2018, five researchers reported on their respective studies on systems biology. The topics included reactions of drugs, ion-transport architecture in an epithelial system, multi-omics in renal disease, cardiac electrophysiological systems, and a software platform for computer simulation. In this review article these authors have summarized recent achievements in the field and discuss next-generation studies on health and disease.
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Affiliation(s)
- Shinichi Uchida
- Department of Nephrology, Graduate Schools of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Yoshiyuki Asai
- Department of Systems Bioinformatics, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan
| | - Yoshiaki Kariya
- Department of Pharmacy, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Kunichika Tsumoto
- Division of Molecular and Cellular Pharmacology, Department of Pharmacology, Osaka University, Suita, Japan.,Center for Advanced Medical Engineering and Informatics, Osaka University, Suita, Japan.,Department of Physiology II, Kanazawa Medical University, Ishikawa, 920-0293, Japan
| | - Hiroshi Hibino
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan. .,AMED-CREST, AMED, Niigata, Japan.
| | - Masashi Honma
- Department of Pharmacy, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Takeshi Abe
- Department of Systems Bioinformatics, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan
| | - Fumiaki Nin
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan.,AMED-CREST, AMED, Niigata, Japan
| | - Yasutaka Kurata
- Department of Physiology II, Kanazawa Medical University, Ishikawa, 920-0293, Japan
| | - Kazuharu Furutani
- Department of Physiology and Membrane Biology, University of California Davis, Davis, 95616, USA
| | - Hiroshi Suzuki
- Department of Pharmacy, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Hiroaki Kitano
- The Systems Biology Institute, Shinagawa-ku, Tokyo, 108-0071, Japan
| | - Ryuji Inoue
- Department of Physiology, Fukuoka University School of Medicine, 7-45-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan.
| | - Yoshihisa Kurachi
- Division of Molecular and Cellular Pharmacology, Department of Pharmacology, Osaka University, Suita, Japan. .,Center for Advanced Medical Engineering and Informatics, Osaka University, Suita, Japan.
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11
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Furutani K, Tsumoto K, Chen IS, Handa K, Yamakawa Y, Sack JT, Kurachi Y. Facilitation of I Kr current by some hERG channel blockers suppresses early afterdepolarizations. J Gen Physiol 2019; 151:214-230. [PMID: 30674563 PMCID: PMC6363420 DOI: 10.1085/jgp.201812192] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 12/06/2018] [Indexed: 01/01/2023] Open
Abstract
Some hERG channel blockers are clinically safe, but others cause fatal cardiac arrhythmias. Furutani et al. show that safe blockers facilitate channel opening in ventricular myocytes and provide a repolarization reserve at precisely the voltages and times needed to suppress arrhythmias. Drug-induced block of the cardiac rapid delayed rectifying potassium current (IKr), carried by the human ether-a-go-go-related gene (hERG) channel, is the most common cause of acquired long QT syndrome. Indeed, some, but not all, drugs that block hERG channels cause fatal cardiac arrhythmias. However, there is no clear method to distinguish between drugs that cause deadly arrhythmias and those that are clinically safe. Here we propose a mechanism that could explain why certain clinically used hERG blockers are less proarrhythmic than others. We demonstrate that several drugs that block hERG channels, but have favorable cardiac safety profiles, also evoke another effect; they facilitate the hERG current amplitude in response to low-voltage depolarization. To investigate how hERG facilitation impacts cardiac safety, we develop computational models of IKr block with and without this facilitation. We constrain the models using data from voltage clamp recordings of hERG block and facilitation by nifekalant, a safe class III antiarrhythmic agent. Human ventricular action potential simulations demonstrate the ability of nifekalant to suppress ectopic excitations, with or without facilitation. Without facilitation, excessive IKr block evokes early afterdepolarizations, which cause lethal arrhythmias. When facilitation is introduced, early afterdepolarizations are prevented at the same degree of block. Facilitation appears to prevent early afterdepolarizations by increasing IKr during the repolarization phase of action potentials. We empirically test this prediction in isolated rabbit ventricular myocytes and find that action potential prolongation with nifekalant is less likely to induce early afterdepolarization than action potential prolongation with dofetilide, a hERG channel blocker that does not induce facilitation. Our data suggest that hERG channel blockers that induce facilitation increase the repolarization reserve of cardiac myocytes, rendering them less likely to trigger lethal ventricular arrhythmias.
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Affiliation(s)
- Kazuharu Furutani
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan .,Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka, Japan.,Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA
| | - Kunichika Tsumoto
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan.,Department of Physiology, Kanazawa Medical University, Ishikawa, Japan
| | - I-Shan Chen
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Kenichiro Handa
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Yuko Yamakawa
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Jon T Sack
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA
| | - Yoshihisa Kurachi
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan .,Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka, Japan
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12
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Affiliation(s)
- Yosuke Funato
- Department of Cellular RegulationResearch Institute for Microbial Diseases, Osaka UniversitySuitaOsaka565‐0871Japan
| | - Kazuharu Furutani
- Department of PharmacologyGraduate School of MedicineOsaka UniversitySuitaOsaka565‐0871Japan
- Department of Physiology and Membrane BiologyUniversity of CaliforniaDavisCA95616USA
| | - Yoshihisa Kurachi
- Department of PharmacologyGraduate School of MedicineOsaka UniversitySuitaOsaka565‐0871Japan
| | - Hiroaki Miki
- Department of Cellular RegulationResearch Institute for Microbial Diseases, Osaka UniversitySuitaOsaka565‐0871Japan
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13
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Emigh AM, DeMarco KR, Furutani K, Bekker S, Sack JT, Clancy CE, Vorobyov I, Yarov-Yarovoy V. Structural Modeling of hERG Channel Interactions with Drugs using Rosetta. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.2667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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14
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Furutani K, Tsumoto K, Sack JT, Kurachi Y. Facilitation by hERG Channel Blockers Suppresses Early Afterdepolarization of Simulated Cardiac Action Potentials. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.2607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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15
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Funato Y, Furutani K, Kurachi Y, Miki H. CrossTalk proposal: CNNM proteins are Na + /Mg 2+ exchangers playing a central role in transepithelial Mg 2+ (re)absorption. J Physiol 2018; 596:743-746. [PMID: 29383719 DOI: 10.1113/jp275248] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Yosuke Funato
- Department of Cellular Regulation, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kazuharu Furutani
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan.,Department of Physiology and Membrane Biology, University of California, Davis, CA 95616, USA
| | - Yoshihisa Kurachi
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Hiroaki Miki
- Department of Cellular Regulation, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
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16
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Chen IS, Furutani K, Kurachi Y. Structural determinants at the M2 muscarinic receptor modulate the RGS4-GIRK response to pilocarpine by impairment of the receptor voltage sensitivity. Sci Rep 2017; 7:6110. [PMID: 28733581 PMCID: PMC5522400 DOI: 10.1038/s41598-017-05128-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 05/24/2017] [Indexed: 12/23/2022] Open
Abstract
Membrane potential controls the response of the M2 muscarinic receptor to its ligands. Membrane hyperpolarization increases response to the full agonist acetylcholine (ACh) while decreasing response to the partial agonist pilocarpine. We previously have demonstrated that the regulator of G-protein signaling (RGS) 4 protein discriminates between the voltage-dependent responses of ACh and pilocarpine; however, the underlying mechanism remains unclear. Here we show that RGS4 is involved in the voltage-dependent behavior of the M2 muscarinic receptor-mediated signaling in response to pilocarpine. Additionally we revealed structural determinants on the M2 muscarinic receptor underlying the voltage-dependent response. By electrophysiological recording in Xenopus oocytes expressing M2 muscarinic receptor and G-protein-gated inwardly rectifying K+ channels, we quantified voltage-dependent desensitization of pilocarpine-induced current in the presence or absence of RGS4. Hyperpolarization-induced desensitization of the current required for RGS4, also depended on pilocarpine concentration. Mutations of charged residues in the aspartic acid-arginine-tyrosine motif of the M2 muscarinic receptor, but not intracellular loop 3, significantly impaired the voltage-dependence of RGS4 function. Thus, our results demonstrated that voltage-dependence of RGS4 modulation is derived from the M2 muscarinic receptor. These results provide novel insights into how membrane potential impacts G-protein signaling by modulating GPCR communication with downstream effectors.
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Affiliation(s)
- I-Shan Chen
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Kazuharu Furutani
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan. .,Global Center for Medical Engineering and Informatics, Osaka University, Suita, Osaka, 565-0871, Japan.
| | - Yoshihisa Kurachi
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan. .,Global Center for Medical Engineering and Informatics, Osaka University, Suita, Osaka, 565-0871, Japan.
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17
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Deufel C, McLemore L, Fong de los Santos L, Classic K, Park S, Furutani K. OC-0081: Patient Safety Is Improved With An Extensive Incident Learning System—9 Years Of Clinical Evidence. Radiother Oncol 2017. [DOI: 10.1016/s0167-8140(17)30525-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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18
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Yoshida T, Furutani K, Watanabe Y, Ohashi N, Baba H. Analgesic efficacy of bilateral continuous transversus abdominis plane blocks using an oblique subcostal approach in patients undergoing laparotomy for gynaecological cancer: a prospective, randomized, triple-blind, placebo-controlled study. Br J Anaesth 2016; 117:812-820. [DOI: 10.1093/bja/aew339] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2016] [Indexed: 01/22/2023] Open
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19
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Mundy D, Tryggestad E, Beltran C, Furutani K, Gilson G, Ito S, Johnson J, Kruse J, Remmes N, Tasson A, Whitaker T, Herman M. SU-F-T-169: A Periodic Quality Assurance Program for a Spot-Scanning Proton Treatment Facility. Med Phys 2016. [DOI: 10.1118/1.4956306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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20
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Yoshida T, Onishi T, Furutani K, Baba H. A new ultrasound-guided pubic approach for proximal obturator nerve block: clinical study and cadaver evaluation. Anaesthesia 2015; 71:291-7. [DOI: 10.1111/anae.13336] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/23/2015] [Indexed: 11/26/2022]
Affiliation(s)
- T. Yoshida
- Department of Anesthesiology; Niigata University Medical and Dental Hospital; Niigata-city Japan
| | - T. Onishi
- Division of Anesthesiology; Niigata University Graduate School of Medical and Dental Sciences; Niigata-city Japan
| | - K. Furutani
- Division of Anesthesiology; Niigata University Graduate School of Medical and Dental Sciences; Niigata-city Japan
| | - H. Baba
- Division of Anesthesiology; Niigata University Graduate School of Medical and Dental Sciences; Niigata-city Japan
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21
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Merrell K, Davis B, Goulet C, Furutani K, Mynderse L, Wilson T, Deufel C, Birckhead B, Choo R. PO-1039: Comparison of seed migration to the chest after permanent prostate brachytherapy with loose, stranded or mixed seeds. Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)41031-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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22
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Kamide T, Okumura S, Ghosh S, Shinoda Y, Mototani Y, Ohnuki Y, Jin H, Cai W, Suita K, Sato I, Umemura M, Fujita T, Yokoyama U, Sato M, Furutani K, Kitano H, Ishikawa Y. Oscillation of cAMP and Ca(2+) in cardiac myocytes: a systems biology approach. J Physiol Sci 2015; 65:195-200. [PMID: 25585963 PMCID: PMC10717207 DOI: 10.1007/s12576-014-0354-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 12/18/2014] [Indexed: 12/19/2022]
Abstract
Cyclic adenosine monophosphate (cAMP) and Ca(2+) levels may oscillate in harmony within excitable cells; a mathematical oscillation loop model, the Cooper model, of these oscillations was developed two decades ago. However, in that model all adenylyl cyclase (AC) isoforms were assumed to be inhibited by Ca(2+), and it is now known that the heart expresses multiple AC isoforms, among which the type 5/6 isoforms are Ca(2+)-inhibitable whereas the other five (AC2, 3, 4, 7, and 9) are not. We used a computational systems biology approach with CellDesigner simulation software to develop a comprehensive graphical map and oscillation loop model for cAMP and Ca(2+). This model indicated that Ca(2+)-mediated inhibition of AC is essential to create oscillations of Ca(2+) and cAMP, and the oscillations were not altered by incorporation of phosphodiesterase-mediated cAMP hydrolysis or PKA-mediated inhibition of AC into the model. More importantly, they were created but faded out immediately in the co-presence of Ca(2+)-noninhibitable AC isoforms. Because the subcellular locations of AC isoforms are different, spontaneous cAMP and Ca(2+) oscillations may occur within microdomains containing only Ca(2+)-inhibitable isoforms in cardiac myocytes, which might be necessary for fine tuning of excitation-contraction coupling.
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Affiliation(s)
- Takehisa Kamide
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Satoshi Okumura
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-2 Tsurumi, Tsurumi-ku, Yokohama, 230-8501 Japan
| | - Samik Ghosh
- The Systems Biology Institute, Minato, Tokyo, 108-0071 Japan
| | - Yoko Shinoda
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-2 Tsurumi, Tsurumi-ku, Yokohama, 230-8501 Japan
| | - Yasumasa Mototani
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-2 Tsurumi, Tsurumi-ku, Yokohama, 230-8501 Japan
| | - Yoshiki Ohnuki
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-2 Tsurumi, Tsurumi-ku, Yokohama, 230-8501 Japan
| | - Huiling Jin
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Wenqian Cai
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Kenji Suita
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Itaru Sato
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Masanari Umemura
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Takayuki Fujita
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Utako Yokoyama
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Motohiko Sato
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
- Department of Physiology, Aichi Medical University, Nagakute, Aichi 480-1195 Japan
| | - Kazuharu Furutani
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, 565-0871 Japan
- Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka, 565-0871 Japan
| | - Hiroaki Kitano
- The Systems Biology Institute, Minato, Tokyo, 108-0071 Japan
- Okinawa Institute of Science and Technology Graduate School, Onna-Son, Okinawa, 904-0412 Japan
- Laboratory for Disease Systems Modeling, Riken Center for Integrative Medical Sciences, Yokohama, 230-0045 Japan
| | - Yoshihiro Ishikawa
- Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
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23
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Grams M, Wilson Z, Sio T, Beltran C, Tryggestad E, Gupta S, Blackwell C, McCollough K, Sarkaria J, Furutani K. SU-E-T-457: Design and Characterization of An Economical 192Ir Hemi-Brain Small Animal Irradiator. Med Phys 2014. [DOI: 10.1118/1.4888790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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24
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Yoshida T, Fujiwara T, Furutani K, Ohashi N, Baba H. Effects of ropivacaine concentration on the spread of sensory block produced by continuous thoracic paravertebral block: a prospective, randomised, controlled, double-blind study. Anaesthesia 2014; 69:231-9. [DOI: 10.1111/anae.12531] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2013] [Indexed: 11/30/2022]
Affiliation(s)
- T. Yoshida
- Division of Anesthesiology; Niigata University Graduate School of Medical and Dental Sciences; Niigata-city Japan
| | - T. Fujiwara
- Division of Anesthesiology; Niigata University Graduate School of Medical and Dental Sciences; Niigata-city Japan
| | - K. Furutani
- Division of Anesthesiology; Niigata University Graduate School of Medical and Dental Sciences; Niigata-city Japan
| | - N. Ohashi
- Division of Anesthesiology; Niigata University Graduate School of Medical and Dental Sciences; Niigata-city Japan
| | - H. Baba
- Division of Anesthesiology; Niigata University Graduate School of Medical and Dental Sciences; Niigata-city Japan
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25
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Abstract
Partial agonists are used clinically to avoid overstimulation of receptor-mediated signalling, as they produce a submaximal response even at 100% receptor occupancy. The submaximal efficacy of partial agonists is due to conformational change of the agonist–receptor complex, which reduces effector activation. In addition to signalling activators, several regulators help control intracellular signal transductions. However, it remains unclear whether these signalling regulators contribute to partial agonism. Here we show that regulator of G-protein signalling (RGS) 4 is a determinant for partial agonism of the M2 muscarinic receptor (M2R). In rat atrial myocytes, pilocarpine evoked smaller G-protein-gated K+ inwardly rectifying (KG) currents than those evoked by ACh. In a Xenopus oocyte expression system, pilocarpine acted as a partial agonist in the presence of RGS4 as it did in atrial myocytes, while it acted like a full agonist in the absence of RGS4. Functional couplings within the agonist–receptor complex/G-protein/RGS4 system controlled the efficacy of pilocarpine relative to ACh. The pilocarpine–M2R complex suppressed G-protein-mediated activation of KG currents via RGS4. Our results demonstrate that partial agonism of M2R is regulated by the RGS4-mediated inhibition of G-protein signalling. This finding helps us to understand the molecular components and mechanism underlying the partial agonism of M2R-mediated physiological responses.
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Affiliation(s)
- I-Shan Chen
- Division of Molecular and Cellular Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan. or
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26
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Yamakawa Y, Furutani K, Inanobe A, Ohno Y, Kurachi Y. Pharmacophore modeling for hERG channel facilitation. Biochem Biophys Res Commun 2012; 418:161-6. [DOI: 10.1016/j.bbrc.2011.12.153] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 12/31/2011] [Indexed: 10/14/2022]
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27
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Nomura M, Kodaira T, Furutani K, Tachibana H, Tomita N, Goto Y. Predictive factors for radiation pneumonitis in oesophageal cancer patients treated with chemoradiotherapy without prophylactic nodal irradiation. Br J Radiol 2012; 85:813-8. [PMID: 22253344 DOI: 10.1259/bjr/13604628] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE The objective of this study was to identify clinical and dosimetric factors for the development of radiation pneumonitis (RP) among patients with oesophageal cancer treated with three-dimensional radiotherapy without prophylactic nodal irradiation. METHODS 125 patients with oesophageal cancer had undergone dose-volume histogram (DVH) metrics and received chemoradiotherapy (CRT). Several clinical and dosimetric factors with regard to the lung were evaluated as predictive factors for the development of symptomatic RP. RESULTS 26 patients (20.8%) developed symptomatic RP classified as greater than or equal to Grade 2. By univariate analysis, body weight loss, tumour length, Stage IV, response to treatment and all DVH parameters proved to be significant factors for the development of RP (p < 0.05). By multivariate analysis, Stage IV and all dosimetric factors were independent predictive factors for the development of symptomatic RP (p < 0.05). Recursive partitioning analysis indicated that V10 values of 24.8% or more and Stage IV were associated with higher development of RP (odds ratio 6.53). CONCLUSIONS Our study demonstrated that severe RP was also developed in patients treated with the minimal radiation field. Stage IV and the dosimetric factors were identified as independent predictive factors for symptomatic RP in oesophageal cancer patients treated with CRT without prophylactic nodal irradiation.
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Affiliation(s)
- M Nomura
- Department of Radiation Oncology, Aichi Cancer Center Hospital, Aichi, Japan.
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28
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Furutani K, Yamakawa Y, Inanobe A, Iwata M, Ohno Y, Kurachi Y. A mechanism underlying compound-induced voltage shift in the current activation of hERG by antiarrhythmic agents. Biochem Biophys Res Commun 2011; 415:141-6. [PMID: 22020101 DOI: 10.1016/j.bbrc.2011.10.034] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 10/07/2011] [Indexed: 11/24/2022]
Abstract
Nifekalant and azimilide, Class III antiarrhythmic agents, block the human ether-à-go-go-related gene K(+) (hERG) channel. However, when a depolarizing membrane potential is applied, they also increase the current at low potentials by shifting its activation curve towards hyperpolarizing voltages. This phenomenon is called 'facilitation'. In this study, we tried to address the mechanism underlying the facilitation by analyzing the effects of various compounds on hERG expressed in Xenopus oocytes. Like nifekalant, amiodarone, quinidine and carvedilol, but not by dofetilide, caused the current facilitation of hERG, suggesting that the facilitation is a common effect to a subset of hERG blockers. As the concentration of each compound was increased, the total hERG current was suppressed progressively, while the current at low potentials was augmented. Activation curves of the remaining hERG current in the facilitation condition could be described as the sum of two Boltzmann functions reflecting two populations of hERG currents having different activation curves. The voltage shift in the activation curve from control was constant for each compound even at different concentrations; -31 mV in amiodarone, -27 mV in nifekalant, -17 mV in quinidine and -12 mV in carvedilol. Therefore, the facilitation is based on the appearance of hERG whose voltage-dependence for the activation is shifted towards hyperpolarizing voltages.
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Affiliation(s)
- Kazuharu Furutani
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan.
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29
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Goto Y, Ito J, Tomita N, Tachibana H, Furutani K, Kodaira T. The Clinical Outcome And Patterns Of Recurrence Of Limited Field Postoperative Radiotherapy For Squamous-cell Carcinoma Of Head and Neck. Int J Radiat Oncol Biol Phys 2011. [DOI: 10.1016/j.ijrobp.2011.06.779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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30
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Kasuva G, Toita T, Furutani K, Kodaira T, Ohno T, Kaneyasu Y, Yoshimura R, Uno T, Ishikura S, Hiraoka M. 8017 POSTER Distribution Patterns of Metastatic Pelvic Lymph Nodes Assessed by CT/MRI in Patients With Uterine Cervical Cancer. Eur J Cancer 2011. [DOI: 10.1016/s0959-8049(11)72105-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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31
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Kamimura D, Ohtani T, Sakata Y, Mano T, Takeda Y, Tamaki S, Omori Y, Tsukamoto Y, Furutani K, Komiyama Y, Yoshika M, Takahashi H, Matsuda T, Baba A, Umemura S, Miwa T, Komuro I, Yamamoto K. Ca2+ entry mode of Na+/Ca2+ exchanger as a new therapeutic target for heart failure with preserved ejection fraction. Eur Heart J 2011; 33:1408-16. [DOI: 10.1093/eurheartj/ehr106] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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32
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Goto Y, Ito J, Tomita N, Tachibana H, Furutani K, Kodaira T. Re-irradiation Combined with Concurrent Chemotherapy for Patients with Locally Recurrent Nasopharyngeal Carcinoma: Clinical Advantage of Intensity Modulated Radiotherapy using Helical Tomotherapy. Int J Radiat Oncol Biol Phys 2010. [DOI: 10.1016/j.ijrobp.2010.07.1081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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33
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Toita T, Ohno T, Kaneyasu Y, Uno T, Yoshimura R, Kodaira T, Furutani K, Kasuya G, Ishikura S, Kamura T, Hiraoka M. A Consensus-based Guideline Defining the Clinical Target Volume for Pelvic Lymph Nodes in External Beam Radiotherapy for Uterine Cervical Cancer. Jpn J Clin Oncol 2010; 40:456-63. [DOI: 10.1093/jjco/hyp191] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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34
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Hibino H, Inanobe A, Furutani K, Murakami S, Findlay I, Kurachi Y. Inwardly rectifying potassium channels: their structure, function, and physiological roles. Physiol Rev 2010; 90:291-366. [PMID: 20086079 DOI: 10.1152/physrev.00021.2009] [Citation(s) in RCA: 1055] [Impact Index Per Article: 75.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Inwardly rectifying K(+) (Kir) channels allow K(+) to move more easily into rather than out of the cell. They have diverse physiological functions depending on their type and their location. There are seven Kir channel subfamilies that can be classified into four functional groups: classical Kir channels (Kir2.x) are constitutively active, G protein-gated Kir channels (Kir3.x) are regulated by G protein-coupled receptors, ATP-sensitive K(+) channels (Kir6.x) are tightly linked to cellular metabolism, and K(+) transport channels (Kir1.x, Kir4.x, Kir5.x, and Kir7.x). Inward rectification results from pore block by intracellular substances such as Mg(2+) and polyamines. Kir channel activity can be modulated by ions, phospholipids, and binding proteins. The basic building block of a Kir channel is made up of two transmembrane helices with cytoplasmic NH(2) and COOH termini and an extracellular loop which folds back to form the pore-lining ion selectivity filter. In vivo, functional Kir channels are composed of four such subunits which are either homo- or heterotetramers. Gene targeting and genetic analysis have linked Kir channel dysfunction to diverse pathologies. The crystal structure of different Kir channels is opening the way to understanding the structure-function relationships of this simple but diverse ion channel family.
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Affiliation(s)
- Hiroshi Hibino
- Department of Pharmacology, Graduate School of Medicine and The Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka 565-0871, Japan
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35
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Hashimoto T, Asakura H, Kanemoto A, Kubota S, Ogawa H, Harada H, Furutani K, Fuji H, Murayama S, Nishimura T. Cardiac Contouring for the Assessment of Cardiac Toxicity after Chemoradiotherapy for Patients with Esophageal Cancer. Int J Radiat Oncol Biol Phys 2009. [DOI: 10.1016/j.ijrobp.2009.07.629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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36
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Hashii H, Mizumoto M, Harada H, Asakura H, Hashimoto T, Furutani K, Kanemoto A, Katagiri H, Nakasu Y. Radiotherapy for Patients with Symptomatic Intramedullary Spinal Cord Metastases. Int J Radiat Oncol Biol Phys 2009. [DOI: 10.1016/j.ijrobp.2009.07.575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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37
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Mizumoto M, Harada H, Asakura H, Hashimoto T, Furutani K, Murata H, Takagi T, Katagiri H, Takahashi M, Nishimura T. Radiotherapy for the Patients with Metastases to the Spinal Column: A Review of 603 Patients in Terms of Predictive Factors of Local Control and Survival. Int J Radiat Oncol Biol Phys 2009. [DOI: 10.1016/j.ijrobp.2009.07.1154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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38
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Thomson R, Furutani K, Rogers D. WE-D-BRB-03: Novel Plaques for Iris Melanoma I-125 and Pd-103 Brachytherapy. Med Phys 2009. [DOI: 10.1118/1.3182517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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39
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Furutani K, Ohno Y, Inanobe A, Hibino H, Kurachi Y. Mutational and In Silico Analyses for Antidepressant Block of Astroglial Inward-Rectifier Kir4.1 Channel. Mol Pharmacol 2009; 75:1287-95. [DOI: 10.1124/mol.108.052936] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Furutani K, Ohno Y, Inanobe A, Hibino H, Kurachi Y. Mutational and in silico analyses for antidepressant block of astroglial inward-rectifier kir4.1 channel. Neurosci Res 2009. [DOI: 10.1016/j.neures.2009.09.258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Hashimoto T, Asakura H, Zenda S, Hashii H, Mizumoto M, Harada H, Furutani K, Fuji H, Murayama S, Nishimura T. Cardiac Toxicities after Concurrent Chemoradiotherapy for Esophageal Cancer - Dose-volume Histogram (DVH) Analysis. Int J Radiat Oncol Biol Phys 2008. [DOI: 10.1016/j.ijrobp.2008.06.435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Mizumoto M, Harada H, Asakura H, Hashimoto T, Furutani K, Hashii H, Takagi T, Katagiri H, Takahashi M, Nishimura T. Prognostic factors of survival after radiotherapy for metastases to the spinal column and a scoring system of survival: Review of 530 patients in Shizuoka Cancer Center Hospital. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.9608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Fuwa N, Kodaira T, Furutani K, Tachibana H, Nakamura T, Nakahara R, Tomoda T, Inokuchi H, Daimon T. Intra-arterial chemoradiotherapy for locally advanced oral cavity cancer: analysis of therapeutic results in 134 cases. Br J Cancer 2008; 98:1039-45. [PMID: 18283309 PMCID: PMC2275486 DOI: 10.1038/sj.bjc.6604272] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The objective of this study was to investigate the therapeutic results of arterial injection therapy via the superficial temporal artery for 134 cases of stages III and IV (M0) oral cavity cancer retrospectively, and to clarify the prognostic factors. We administered intra-arterial chemoradiotherapy by continuous infusion of carboplatin in 65 cases from January 1993 to July 2002. Systemic chemotherapy was performed on 26 cases at the same time. We administered intra-arterial chemoradiotherapy by cisplatin with sodium thiosulphate in 69 cases from October 2002 to December 2006. Systemic chemotherapy was performed on 48 cases at the same time. The 3-year local control rate was 68.6% (T2-3: 77.9%; T4: 51.3%), and the 3-year survival rate was 53.9% (stage III: 62.9%; stage IV: 45.3%). Regarding the results of multivariate analysis of survival rates, age (<65), selective intra-arterial infusion, and the use of cisplatin as an agent for intra-arterial infusion were significant factors. The therapeutic results of intra-arterial chemoradiotherapy via the superficial temporal artery were not inferior to the results of surgery. In particular, the results of arterial injection therapy by cisplatin with sodium thiosulphate were excellent, so we believe that it will be a new therapy for advanced oral cavity cancer.
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Affiliation(s)
- N Fuwa
- Department of Radiation Oncology, Aichi Cancer Center Hospital, Nagoya, Japan.
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Davis B, Goulet C, Furutani K, Mynderse L, Wilson T. MP-18.14: Seed migration rate to the chest following permanent prostate brachytherapy is markedly reduced with the use of seeds in vicryl suture material. Urology 2007. [DOI: 10.1016/j.urology.2007.06.520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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45
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Kakizawa S, Kishimoto Y, Hashimoto K, Miyazaki T, Furutani K, Shimizu H, Fukaya M, Nishi M, Sakagami H, Ikeda A, Kondo H, Kano M, Watanabe M, Iino M, Takeshima H. Junctophilin-mediated channel crosstalk essential for cerebellar synaptic plasticity. EMBO J 2007; 26:1924-33. [PMID: 17347645 PMCID: PMC1847665 DOI: 10.1038/sj.emboj.7601639] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Accepted: 02/08/2007] [Indexed: 12/18/2022] Open
Abstract
Functional crosstalk between cell-surface and intracellular ion channels plays important roles in excitable cells and is structurally supported by junctophilins (JPs) in muscle cells. Here, we report a novel form of channel crosstalk in cerebellar Purkinje cells (PCs). The generation of slow afterhyperpolarization (sAHP) following complex spikes in PCs required ryanodine receptor (RyR)-mediated Ca(2+)-induced Ca(2+) release and the subsequent opening of small-conductance Ca(2+)-activated K(+) (SK) channels in somatodendritic regions. Despite the normal expression levels of these channels, sAHP was abolished in PCs from mutant mice lacking neural JP subtypes (JP-DKO), and this defect was restored by exogenously expressing JPs or enhancing SK channel activation. The stimulation paradigm for inducing long-term depression (LTD) at parallel fiber-PC synapses adversely established long-term potentiation in the JP-DKO cerebellum, primarily due to the sAHP deficiency. Furthermore, JP-DKO mice exhibited impairments of motor coordination and learning, although normal cerebellar histology was retained. Therefore, JPs support the Ca(2+)-mediated communication between voltage-gated Ca(2+) channels, RyRs and SK channels, which modulates the excitability of PCs and is fundamental to cerebellar LTD and motor functions.
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Affiliation(s)
- Sho Kakizawa
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yasushi Kishimoto
- Department of Cellular Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Kouichi Hashimoto
- Department of Cellular Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Sapporo, Japan
| | - Taisuke Miyazaki
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Sapporo, Japan
| | - Kazuharu Furutani
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hidemi Shimizu
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Masahiro Fukaya
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Miyuki Nishi
- Department of Biological Chemistry, Kyoto University Graduate School of Pharmaceutical Sciences, Kyoto, Japan
| | - Hiroyuki Sakagami
- Department of Cell Biology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Atsushi Ikeda
- Department of Biological Chemistry, Kyoto University Graduate School of Pharmaceutical Sciences, Kyoto, Japan
| | - Hisatake Kondo
- Department of Cell Biology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Masanobu Kano
- Department of Cellular Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Masamitsu Iino
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hiroshi Takeshima
- Department of Biological Chemistry, Kyoto University Graduate School of Pharmaceutical Sciences, Kyoto, Japan
- Department of Biological Chemistry, Kyoto University Graduate School of Pharmaceutical Sciences, Kyoto 606-8501, Japan. Tel.: +81 75 753 4572; Fax: +81 75 753 4605; E-mail:
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Minehan KJ, Furutani K, McNamara K, Groshek D, Mitchell E, Price M, Emme M, Harms T. Prostate brachytherapy post implant dosimetry: Timing matters. J Clin Oncol 2006. [DOI: 10.1200/jco.2006.24.18_suppl.14597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
14597 Background: Permanent seed implant (PSI) brachytherapy is a common treatment modality for low-risk prostate cancer. Post implant dosimetry (PID) is utilized to asses the quality of the implant. Significant prostate swelling occurs as a result of the implant procedure, and this swelling subsides over time. PID completed on Day 0 after the implant procedure captures the prostate swelling from the procedure. Conversely, PID completed one month later does not have this swelling. PID can therefore show great variation, depending on the timing of the analysis. It is hypothesized that PID completed on Day 0 demonstrates lower dosimetric parameters than PID completed one month later. Methods: Thirteen low risk prostate cancer patients, (Stage ≤ T2, PSA < 13.9, Gleason Score ≤7) were implanted with 125Iodine seeds, with a prescription dose of 145Gy to the prostate plus a 5mm margin. Computed Tomography (CT) PID was completed for each patient on day 0 and on average 33 days following the implant. The prostate was contoured on each axial CT image and the data was analyzed using commercially available PSI planning software. The dose which encompassed 90% of the prostate volume (D90) was calculated for day 0 and day 33 PID. Results: On average, the prostate volume contoured was larger on day 0 PID (Avg. 44.9 cc; range 19–97 cc) compared to day 33 PID (Avg. 38.9 cc; range 18–59 cc) (P = 0.068). The D90 values however, were significantly higher on day 33 PID (Avg.163.7 Gy; range 125–212 Gy) than on day 0 PID (Avg.149 Gy; range 112–166 Gy) (P = 0.003). This D90 relationship was even demonstrated paradoxically in two patients whose contoured prostate volume was larger on the day 33 PID as compared to the day 0 PID. Conclusions: Timing does matter in the analysis of post implant dosimetry for PSI brachytherapy. The D90 values were significantly greater on day 33 PID compared to Day 0 PID while the contoured prostate volumes were not. Future studies which use PID planning to evaluate implant quality should specify the timing of the PID, as this would facilitate cross study comparison. No significant financial relationships to disclose.
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Affiliation(s)
- K. J. Minehan
- Mayo Clinic, Rochester, MN; Franciscan Skemp Heathcare/Mayo Health System, LaCrosse, WI
| | - K. Furutani
- Mayo Clinic, Rochester, MN; Franciscan Skemp Heathcare/Mayo Health System, LaCrosse, WI
| | - K. McNamara
- Mayo Clinic, Rochester, MN; Franciscan Skemp Heathcare/Mayo Health System, LaCrosse, WI
| | - D. Groshek
- Mayo Clinic, Rochester, MN; Franciscan Skemp Heathcare/Mayo Health System, LaCrosse, WI
| | - E. Mitchell
- Mayo Clinic, Rochester, MN; Franciscan Skemp Heathcare/Mayo Health System, LaCrosse, WI
| | - M. Price
- Mayo Clinic, Rochester, MN; Franciscan Skemp Heathcare/Mayo Health System, LaCrosse, WI
| | - M. Emme
- Mayo Clinic, Rochester, MN; Franciscan Skemp Heathcare/Mayo Health System, LaCrosse, WI
| | - T. Harms
- Mayo Clinic, Rochester, MN; Franciscan Skemp Heathcare/Mayo Health System, LaCrosse, WI
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Furutani K, Okubo Y, Kakizawa S, Iino M. Postsynaptic inositol 1,4,5-trisphosphate signaling maintains presynaptic function of parallel fiber-Purkinje cell synapses via BDNF. Proc Natl Acad Sci U S A 2006; 103:8528-33. [PMID: 16709674 PMCID: PMC1482525 DOI: 10.1073/pnas.0600497103] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The maintenance of synaptic functions is essential for neuronal information processing, but cellular mechanisms that maintain synapses in the adult brain are not well understood. Here, we report an activity-dependent maintenance mechanism of parallel fiber (PF)-Purkinje cell (PC) synapses in the cerebellum. When postsynaptic metabotropic glutamate receptor (mGluR) or inositol 1,4,5-trisphosphate (IP(3)) signaling was chronically inhibited in vivo, PF-PC synaptic strength decreased because of a decreased transmitter release probability. The same effects were observed when PF activity was inhibited in vivo by the suppression of NMDA receptor-mediated inputs to granule cells. PF-PC synaptic strength similarly decreased after the in vivo application of an antibody against brain-derived neurotrophic factor (BDNF). Furthermore, the weakening of synaptic connection caused by the blockade of mGluR-IP(3) signaling was reversed by the in vivo application of BDNF. These results indicate that a signaling cascade comprising PF activity, postsynaptic mGluR-IP(3) signaling and subsequent BDNF signaling maintains presynaptic functions in the mature cerebellum.
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Affiliation(s)
- Kazuharu Furutani
- Department of Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan
| | - Yohei Okubo
- Department of Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan
| | - Sho Kakizawa
- Department of Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan
| | - Masamitsu Iino
- Department of Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan
- *To whom correspondence should be addressed. E-mail:
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Furutani K, Akhtar A, Dahl R, Harms T. Po-Poster - 04: A daily quality assurance measurement for dynamic MLC treatments. Med Phys 2005. [DOI: 10.1118/1.2030983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Fuwa N, Kodaira T, Furutani K, Tachibana H, Toita K, Shikama N, Kano M, Yuta A, Hayashi N, Onishi H. Excellent treatment results of alternating chemoradiotherapy for nasopharyngeal cancer-A phase II study-. J Clin Oncol 2005. [DOI: 10.1200/jco.2005.23.16_suppl.5570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- N. Fuwa
- Aichi Cancer Ctr, Nagoya, Japan; Ryukyu Univ, Naha, Japan; Sinsyu Univ, Matsumoto, Japan; Fukushima Univ, Fukushima, Japan; Mie Univ, Tsu, Japan; Nagasaki univrsity, Nagasaki, Japan; Ymanashi Univ, Koufu, Japan
| | - T. Kodaira
- Aichi Cancer Ctr, Nagoya, Japan; Ryukyu Univ, Naha, Japan; Sinsyu Univ, Matsumoto, Japan; Fukushima Univ, Fukushima, Japan; Mie Univ, Tsu, Japan; Nagasaki univrsity, Nagasaki, Japan; Ymanashi Univ, Koufu, Japan
| | - K. Furutani
- Aichi Cancer Ctr, Nagoya, Japan; Ryukyu Univ, Naha, Japan; Sinsyu Univ, Matsumoto, Japan; Fukushima Univ, Fukushima, Japan; Mie Univ, Tsu, Japan; Nagasaki univrsity, Nagasaki, Japan; Ymanashi Univ, Koufu, Japan
| | - H. Tachibana
- Aichi Cancer Ctr, Nagoya, Japan; Ryukyu Univ, Naha, Japan; Sinsyu Univ, Matsumoto, Japan; Fukushima Univ, Fukushima, Japan; Mie Univ, Tsu, Japan; Nagasaki univrsity, Nagasaki, Japan; Ymanashi Univ, Koufu, Japan
| | - K. Toita
- Aichi Cancer Ctr, Nagoya, Japan; Ryukyu Univ, Naha, Japan; Sinsyu Univ, Matsumoto, Japan; Fukushima Univ, Fukushima, Japan; Mie Univ, Tsu, Japan; Nagasaki univrsity, Nagasaki, Japan; Ymanashi Univ, Koufu, Japan
| | - N. Shikama
- Aichi Cancer Ctr, Nagoya, Japan; Ryukyu Univ, Naha, Japan; Sinsyu Univ, Matsumoto, Japan; Fukushima Univ, Fukushima, Japan; Mie Univ, Tsu, Japan; Nagasaki univrsity, Nagasaki, Japan; Ymanashi Univ, Koufu, Japan
| | - M. Kano
- Aichi Cancer Ctr, Nagoya, Japan; Ryukyu Univ, Naha, Japan; Sinsyu Univ, Matsumoto, Japan; Fukushima Univ, Fukushima, Japan; Mie Univ, Tsu, Japan; Nagasaki univrsity, Nagasaki, Japan; Ymanashi Univ, Koufu, Japan
| | - A. Yuta
- Aichi Cancer Ctr, Nagoya, Japan; Ryukyu Univ, Naha, Japan; Sinsyu Univ, Matsumoto, Japan; Fukushima Univ, Fukushima, Japan; Mie Univ, Tsu, Japan; Nagasaki univrsity, Nagasaki, Japan; Ymanashi Univ, Koufu, Japan
| | - N. Hayashi
- Aichi Cancer Ctr, Nagoya, Japan; Ryukyu Univ, Naha, Japan; Sinsyu Univ, Matsumoto, Japan; Fukushima Univ, Fukushima, Japan; Mie Univ, Tsu, Japan; Nagasaki univrsity, Nagasaki, Japan; Ymanashi Univ, Koufu, Japan
| | - H. Onishi
- Aichi Cancer Ctr, Nagoya, Japan; Ryukyu Univ, Naha, Japan; Sinsyu Univ, Matsumoto, Japan; Fukushima Univ, Fukushima, Japan; Mie Univ, Tsu, Japan; Nagasaki univrsity, Nagasaki, Japan; Ymanashi Univ, Koufu, Japan
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Nakamura E, Kataoka T, Furutani K, Jimbo K, Aihara T, Tanaka S, Ichikawa A, Ohtsu H, Okabe S. Lack of histamine alters gastric mucosal morphology: comparison of histidine decarboxylase-deficient and mast cell-deficient mice. Am J Physiol Gastrointest Liver Physiol 2004; 287:G1053-61. [PMID: 15271653 DOI: 10.1152/ajpgi.00353.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Histamine plays an important role in the regulation of gastric acid secretion; however, its role in maintenance of gastric morphology remains unclear. To clarify the necessity of histamine for gastric mucosal development and maintenance, we evaluated two different kinds of mice that lacked either mast cells (one of the gastric histamine-producing cell types) or histidine decarboxylase (HDC; a histamine-synthesizing enzyme). Measurements of stomach weight, intragastric pH, mucosal histamine levels, as well as serum gastrin and albumin levels were performed in mice. Gastric mucosal appearance was examined by immunohistochemical techniques. Although gastric mucosal histamine levels in mast cell-deficient mice were half of those observed in the wild-type mice, intragastric pH, serum gastrin levels, and gastric morphology at 12 mo were unchanged compared with the wild-type mice. In contrast, HDC-deficient mice possessed no detectable gastric histamine, but did exhibit hypergastrinemia, as well as marked increases in intragastric pH and stomach weight compared with the wild-type mice. Histological analysis revealed that 9-mo-old HDC-deficient mice demonstrated hyperplasia in the oxyntic glandular base region, as well as increased numbers of parietal and enterochromaffin-like cells. These results indicate that enterochromaffin-like cell-derived histamine is potentially involved in gastric mucosal morphology regulation.
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Affiliation(s)
- Eiji Nakamura
- Department of Applied Pharmacology, Kyoto Pharmaceutical University, Misasagi, Yamashina, Kyoto 607-8414, Japan
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