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Dong C, Li J, Ding W, Ueda R, Xie X, Wu J, Matsuura H, Horie M. Open channel block of Kv1.5 channels by HMQ1611. Front Pharmacol 2022; 13:965086. [PMID: 36188606 PMCID: PMC9524145 DOI: 10.3389/fphar.2022.965086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 08/26/2022] [Indexed: 11/13/2022] Open
Abstract
Kv1.5 channels conduct the ultra-rapid delayed rectifier potassium current (IKur). Pharmacological blockade of human Kv1.5 (hKv1.5) has been regarded as an effective treatment of re-entrant based atrial fibrillation, because Kv1.5 is highly expressed in human cardiac atria but scarcely in ventricles. The Kv1.5 blockade is also expected to be used in cancer therapeutics since Kv1.5 is overexpressed in some types of human tumors. Here, we investigated the blockade of hKv1.5 channels by HMQ1611, a symmetrical biphenyl derivative. hKv1.5 channels were heterologously expressed in Chinese hamster ovary cells. The effects of HMQ1611 on wild-type and 13 hKv1.5 mutant channels were examined using the whole-cell patch-clamp method, and molecular docking simulation was conducted to predict the docking position of HMQ1611 within Kv1.5 channels. We showed that HMQ1611 reversibly inhibited the hKv1.5 current in a concentration-dependent manner (IC50 = 2.07 μM). HMQ1611 blockade of hKv1.5 current developed with time during depolarizing voltage-clamp steps, and this blockade was also voltage-dependent with a steep increase over the voltage range for channel openings. HMQ1611 inhibition was significantly reduced in the T479A, T480A, V505A, I508A, L510A, V512A, and V516A hKv1.5 mutant channels. Molecular docking analysis predicted that V505, V512, and T480 were involved in the blocking action of HMQ1611 on hKv1.5 channels. These results suggest that HMQ1611 inhibits hKv1.5 currents as an open channel blocker. Amino acid residues located at the base of the selectivity filter (T479 and T480) and in the S6 segment (V505, I508, L510, V512, and V516) of hKv1.5 appear to constitute potential binding sites for HMQ1611.
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Affiliation(s)
- Chao Dong
- Department of Pharmacology, School of Basic Medical Science, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi, China
- Key Laboratory of Environment and Genes Related to Diseases, Xi’an Jiaotong University, Ministry of Education, Xi’an, Shaanxi, China
- Department of Pharmacy, The First Affiliated Hospital of Xi’an Medical University, Xi’an, China
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Jiawei Li
- Department of Pharmacology, School of Basic Medical Science, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi, China
- Key Laboratory of Environment and Genes Related to Diseases, Xi’an Jiaotong University, Ministry of Education, Xi’an, Shaanxi, China
| | - Weiguang Ding
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Rika Ueda
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Xiaolu Xie
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Jie Wu
- Department of Pharmacology, School of Basic Medical Science, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi, China
- Key Laboratory of Environment and Genes Related to Diseases, Xi’an Jiaotong University, Ministry of Education, Xi’an, Shaanxi, China
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
- *Correspondence: Jie Wu,
| | - Hiroshi Matsuura
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Minoru Horie
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
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Mazola Y, Márquez Montesinos JCE, Ramírez D, Zúñiga L, Decher N, Ravens U, Yarov-Yarovoy V, González W. Common Structural Pattern for Flecainide Binding in Atrial-Selective Kv1.5 and Nav1.5 Channels: A Computational Approach. Pharmaceutics 2022; 14:pharmaceutics14071356. [PMID: 35890252 PMCID: PMC9318806 DOI: 10.3390/pharmaceutics14071356] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/20/2022] [Accepted: 06/20/2022] [Indexed: 02/04/2023] Open
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia. Its treatment includes antiarrhythmic drugs (AADs) to modulate the function of cardiac ion channels. However, AADs have been limited by proarrhythmic effects, non-cardiovascular toxicities as well as often modest antiarrhythmic efficacy. Theoretical models showed that a combined blockade of Nav1.5 (and its current, INa) and Kv1.5 (and its current, IKur) ion channels yield a synergistic anti-arrhythmic effect without alterations in ventricles. We focused on Kv1.5 and Nav1.5 to search for structural similarities in their binding site (BS) for flecainide (a common blocker and widely prescribed AAD) as a first step for prospective rational multi-target directed ligand (MTDL) design strategies. We present a computational workflow for a flecainide BS comparison in a flecainide-Kv1.5 docking model and a solved structure of the flecainide-Nav1.5 complex. The workflow includes docking, molecular dynamics, BS characterization and pattern matching. We identified a common structural pattern in flecainide BS for these channels. The latter belongs to the central cavity and consists of a hydrophobic patch and a polar region, involving residues from the S6 helix and P-loop. Since the rational MTDL design for AF is still incipient, our findings could advance multi-target atrial-selective strategies for AF treatment.
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Affiliation(s)
- Yuliet Mazola
- Center for Bioinformatics, Simulation and Modeling (CBSM), Universidad de Talca, Talca 3460000, Chile; (Y.M.); (J.C.E.M.M.)
| | - José C. E. Márquez Montesinos
- Center for Bioinformatics, Simulation and Modeling (CBSM), Universidad de Talca, Talca 3460000, Chile; (Y.M.); (J.C.E.M.M.)
| | - David Ramírez
- Departamento de Farmacología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción 4030000, Chile;
| | - Leandro Zúñiga
- Escuela de Medicina, Centro de Investigaciones Médicas, Universidad de Talca, Talca 3460000, Chile;
| | - Niels Decher
- Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, 35043 Marburg, Germany;
| | - Ursula Ravens
- Institut für Experimentelle Kardiovaskuläre Medizin, Universitäts-Herzzentrum Freiburg Bad Krotzingen, 79110 Freiburg im Breisgau, Germany;
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California, Davis, CA 95616, USA;
| | - Wendy González
- Center for Bioinformatics, Simulation and Modeling (CBSM), Universidad de Talca, Talca 3460000, Chile; (Y.M.); (J.C.E.M.M.)
- Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Talca 3530000, Chile
- Correspondence:
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Qin W, Li YH, Tong J, Wu J, Zhao D, Li HJ, Xing L, He CX, Zhou X, Li PQ, Meng G, Wu SP, Cao HL. Rational Design and Synthesis of 3-Morpholine Linked Aromatic-Imino-1H-Indoles as Novel Kv1.5 Channel Inhibitors Sharing Vasodilation Effects. Front Mol Biosci 2022; 8:805594. [PMID: 35141279 PMCID: PMC8819089 DOI: 10.3389/fmolb.2021.805594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 12/28/2021] [Indexed: 11/25/2022] Open
Abstract
Atrial fibrillation (AF) is the most common clinical sustained arrhythmia; clinical therapeutic drugs have low atrial selectivity and might cause more severe ventricle arrhythmias while stopping AF. As an anti-AF drug target with high selectivity on the atrial muscle cells, the undetermined crystal structure of Kv1.5 potassium channel impeded further new drug development. Herein, with the simulated 3D structure of Kv1.5 as the drug target, a series of 3-morpholine linked aromatic amino substituted 1H-indoles as novel Kv1.5 channel inhibitors were designed and synthesized based on target–ligand interaction analysis. The synthesis route was practical, starting from commercially available material, and the chemical structures of target compounds were characterized. It was indicated that compounds T16 and T5 (100 μM) exhibited favorable inhibitory activity against the Kv1.5 channel with an inhibition rate of 70.8 and 57.5% using a patch clamp technique. All compounds did not exhibit off-target effects against other drug targets, which denoted some selectivity on the Kv1.5 channel. Interestingly, twelve compounds exhibited favorable vasodilation activity on pre-contracted arterial rings in vitro using KCl or phenylephrine (PE) by a Myograph. The vasodilation rates of compounds T16 and T4 (100 μM) even reached over 90%, which would provide potential lead compounds for both anti-AF and anti-hypertension new drug development.
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Affiliation(s)
- Wei Qin
- Xi’an Key Laboratory of Basic and Translation of Cardiovascular Metabolic Disease, Shaanxi Key Laboratory of Ischemic Cardiovascular Disease, Institute of Basic and Translational Medicine, Xi’an Medical University, Xi’an, China
| | - Yi-Heng Li
- College of Life Sciences, Northwest University, Xi’an, China
| | - Jing Tong
- School of Pharmacy, Health Science Center, Xi’an Jiaotong University, Xi’an, China
| | - Jie Wu
- School of Pharmacy, Health Science Center, Xi’an Jiaotong University, Xi’an, China
| | - Dong Zhao
- Xi’an Key Laboratory of Basic and Translation of Cardiovascular Metabolic Disease, Shaanxi Key Laboratory of Ischemic Cardiovascular Disease, Institute of Basic and Translational Medicine, Xi’an Medical University, Xi’an, China
| | - Hui-Jin Li
- Xi’an Key Laboratory of Basic and Translation of Cardiovascular Metabolic Disease, Shaanxi Key Laboratory of Ischemic Cardiovascular Disease, Institute of Basic and Translational Medicine, Xi’an Medical University, Xi’an, China
| | - Lu Xing
- Xi’an Key Laboratory of Basic and Translation of Cardiovascular Metabolic Disease, Shaanxi Key Laboratory of Ischemic Cardiovascular Disease, Institute of Basic and Translational Medicine, Xi’an Medical University, Xi’an, China
| | - Chun-Xia He
- Xi’an Key Laboratory of Basic and Translation of Cardiovascular Metabolic Disease, Shaanxi Key Laboratory of Ischemic Cardiovascular Disease, Institute of Basic and Translational Medicine, Xi’an Medical University, Xi’an, China
| | - Xin Zhou
- Xi’an Key Laboratory of Basic and Translation of Cardiovascular Metabolic Disease, Shaanxi Key Laboratory of Ischemic Cardiovascular Disease, Institute of Basic and Translational Medicine, Xi’an Medical University, Xi’an, China
| | - Peng-Quan Li
- Xi’an Key Laboratory of Basic and Translation of Cardiovascular Metabolic Disease, Shaanxi Key Laboratory of Ischemic Cardiovascular Disease, Institute of Basic and Translational Medicine, Xi’an Medical University, Xi’an, China
| | - Ge Meng
- School of Pharmacy, Health Science Center, Xi’an Jiaotong University, Xi’an, China
- Engineering Center of Catalysis and Synthesis for Chiral Molecules, Shanghai Engineering Center of Industrial Asymmetric Catalysis for Chiral Drugs, Fudan University, Shanghai, China
- *Correspondence: Ge Meng, ; Shao-Ping Wu, ; Hui-Ling Cao,
| | - Shao-Ping Wu
- College of Life Sciences, Northwest University, Xi’an, China
- *Correspondence: Ge Meng, ; Shao-Ping Wu, ; Hui-Ling Cao,
| | - Hui-Ling Cao
- Xi’an Key Laboratory of Basic and Translation of Cardiovascular Metabolic Disease, Shaanxi Key Laboratory of Ischemic Cardiovascular Disease, Institute of Basic and Translational Medicine, Xi’an Medical University, Xi’an, China
- College of Life Sciences, Northwest University, Xi’an, China
- *Correspondence: Ge Meng, ; Shao-Ping Wu, ; Hui-Ling Cao,
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Targeting of Potassium Channels in Cardiac Arrhythmias. Trends Pharmacol Sci 2021; 42:491-506. [PMID: 33858691 DOI: 10.1016/j.tips.2021.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/14/2021] [Accepted: 03/17/2021] [Indexed: 02/07/2023]
Abstract
Cardiomyocytes are endowed with a complex repertoire of ion channels, responsible for the generation of action potentials (APs), travelling waves of electrical excitation, propagating throughout the heart and leading to cardiac contractions. Cardiac AP waveforms are shaped by a striking diversity of K+ channels. The pivotal role of K+ channels in cardiac health and disease is underscored by the dramatic impact that K+ channel dysfunction has on cardiac arrhythmias. The development of drugs targeted to specific K+ channels is expected to provide an optimized approach to antiarrhythmic therapy. Here, we review the functional roles of cardiac potassium channels under normal and diseased states. We survey current antiarrhythmic drugs (AADs) targeted to voltage-gated and Ca2+-activated K+ channels and highlight future research opportunities.
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Geng M, Lin A, Nguyen TP. Revisiting Antiarrhythmic Drug Therapy for Atrial Fibrillation: Reviewing Lessons Learned and Redefining Therapeutic Paradigms. Front Pharmacol 2020; 11:581837. [PMID: 33240090 PMCID: PMC7680856 DOI: 10.3389/fphar.2020.581837] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/17/2020] [Indexed: 12/12/2022] Open
Abstract
Since the clinical use of digitalis as the first pharmacological therapy for atrial fibrillation (AF) 235 years ago in 1785, antiarrhythmic drug therapy has advanced considerably and become a cornerstone of AF clinical management. Yet, a preventive or curative panacea for sustained AF does not exist despite the rise of AF global prevalence to epidemiological proportions. While multiple elevated risk factors for AF have been established, the natural history and etiology of AF remain incompletely understood. In the present article, the first section selectively highlights some disappointing shortcomings and current efforts in antiarrhythmic drug therapy to uncover reasons why AF is such a clinical challenge. The second section discusses some modern takes on the natural history of AF as a relentless, progressive fibro-inflammatory "atriomyopathy." The final section emphasizes the need to redefine therapeutic strategies on par with new insights of AF pathophysiology.
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Affiliation(s)
| | | | - Thao P. Nguyen
- Division of Cardiology, Department of Medicine, The Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
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Fukushima Y, Kojima A, Mi X, Ding WG, Kitagawa H, Matsuura H. Open-channel blocking action of volatile anaesthetics desflurane and sevoflurane on human voltage-gated K v 1.5 channel. Br J Pharmacol 2020; 177:3811-3827. [PMID: 32436224 DOI: 10.1111/bph.15105] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 04/28/2020] [Accepted: 05/01/2020] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Volatile anaesthetics have been shown to differentially modulate mammalian Shaker-related voltage-gated potassium (Kv 1.x) channels. This study was designed to investigate molecular and cellular mechanisms underlying the modulatory effects of desflurane or sevoflurane on human Kv 1.5 (hKv 1.5) channels. EXPERIMENTAL APPROACH Thirteen single-point mutations were constructed within pore domain of hKv 1.5 channel using site-directed mutagenesis. The effects of desflurane or sevoflurane on heterologously expressed wild-type and mutant hKv 1.5 channels were examined by whole-cell patch-clamp technique. A computer simulation was conducted to predict the docking pose of desflurane or sevoflurane within hKv 1.5 channel. KEY RESULTS Both desflurane and sevoflurane increased hKv 1.5 current at mild depolarizations but decreased it at strong depolarizations, indicating that these anaesthetics produce both stimulatory and inhibitory actions on hKv 1.5 channels. The inhibitory effect of desflurane or sevoflurane on hKv 1.5 channels arose primarily from its open-channel blocking action. The inhibitory action of desflurane or sevoflurane on hKv 1.5 channels was significantly attenuated in T480A, V505A, and I508A mutant channels, compared with wild-type channel. Computational docking simulation predicted that desflurane or sevoflurane resides within the inner cavity of channel pore and has contact with Thr479, Thr480, Val505, and Ile508. CONCLUSION AND IMPLICATIONS Desflurane and sevoflurane exert an open-channel blocking action on hKv 1.5 channels by functionally interacting with specific amino acids located within the channel pore. This study thus identifies a novel molecular basis mediating inhibitory modulation of hKv 1.5 channels by desflurane and sevoflurane.
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Affiliation(s)
- Yutaka Fukushima
- Department of Physiology, Shiga University of Medical Science, Otsu, Japan.,Department of Anesthesiology, Shiga University of Medical Science, Otsu, Japan
| | - Akiko Kojima
- Department of Anesthesiology, Shiga University of Medical Science, Otsu, Japan
| | - Xinya Mi
- Department of Physiology, Shiga University of Medical Science, Otsu, Japan
| | - Wei-Guang Ding
- Department of Physiology, Shiga University of Medical Science, Otsu, Japan
| | - Hirotoshi Kitagawa
- Department of Anesthesiology, Shiga University of Medical Science, Otsu, Japan
| | - Hiroshi Matsuura
- Department of Physiology, Shiga University of Medical Science, Otsu, Japan
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Zhao Z, Ruan S, Ma X, Feng Q, Xie Z, Nie Z, Fan P, Qian M, He X, Wu S, Zhang Y, Zheng X. Challenges Faced with Small Molecular Modulators of Potassium Current Channel Isoform Kv1.5. Biomolecules 2019; 10:E10. [PMID: 31861703 PMCID: PMC7022446 DOI: 10.3390/biom10010010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/08/2019] [Accepted: 12/10/2019] [Indexed: 12/30/2022] Open
Abstract
The voltage-gated potassium channel Kv1.5, which mediates the cardiac ultra-rapid delayed-rectifier (IKur) current in human cells, has a crucial role in atrial fibrillation. Therefore, the design of selective Kv1.5 modulators is essential for the treatment of pathophysiological conditions involving Kv1.5 activity. This review summarizes the progress of molecular structures and the functionality of different types of Kv1.5 modulators, with a focus on clinical cardiovascular drugs and a number of active natural products, through a summarization of 96 compounds currently widely used. Furthermore, we also discuss the contributions of Kv1.5 and the regulation of the structure-activity relationship (SAR) of synthetic Kv1.5 inhibitors in human pathophysiology. SAR analysis is regarded as a useful strategy in structural elucidation, as it relates to the characteristics that improve compounds targeting Kv1.5. Herein, we present previous studies regarding the structural, pharmacological, and SAR information of the Kv1.5 modulator, through which we can assist in identifying and designing potent and specific Kv1.5 inhibitors in the treatment of diseases involving Kv1.5 activity.
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Affiliation(s)
- Zefeng Zhao
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Songsong Ruan
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Xiaoming Ma
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Qian Feng
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Zhuosong Xie
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Zhuang Nie
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Peinan Fan
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Mingcheng Qian
- Department of Medicinal Chemistry, School of Pharmaceutical Engineering and Life Science, Changzhou University, Changzhou 213164, China;
- Laboratory for Medicinal Chemistry, Ghent University, Ottergemsesteenweg 460, B-9000 Ghent, Belgium
| | - Xirui He
- Department of Bioengineering, Zhuhai Campus of Zunyi Medical University, Zhuhai 519041, China;
| | - Shaoping Wu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Yongmin Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
- Sorbonne Université, Institut Parisien de Chimie Moléculaire, CNRS UMR 8232, 4 place Jussieu, 75005 Paris, France
| | - Xiaohui Zheng
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
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Fan TT, Zhang HH, Tang YH, Zhang FZ, Han BN. Two New Neo-debromoaplysiatoxins-A Pair of Stereoisomers Exhibiting Potent Kv1.5 Ion Channel Inhibition Activities. Mar Drugs 2019; 17:E652. [PMID: 31766406 PMCID: PMC6950415 DOI: 10.3390/md17120652] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/15/2019] [Accepted: 11/16/2019] [Indexed: 11/17/2022] Open
Abstract
A pair of stereoisomers possessing novel structures with 6/6/5 fused-ring systems, neo-debromoaplysiatoxin E (1) and neo-debromoaplysiatoxin F (2), were isolated from the marine cyanobacterium Lyngbya sp. Their structures were elucidated using various spectroscopic techniques including high resolution electrospray ionization mass spectroscopy (HRESIMS) and nuclear magnetic resonance (NMR). The absolute stereochemistry was determined by calculated electronic circular dichroism (ECD) and gauge-independent atomic orbital (GIAO) NMR shift calculation followed by DP4+ analysis. Significantly, this is the first report on aplysiatoxin derivatives with different absolute configurations at C9-C12 (1: 9S, 10R, 11S, 12S; 2: 9R, 10S, 11R, 12R). Compounds 1 and 2 exhibited potent blocking activities against Kv1.5 with IC50 values of 1.22 ± 0.22 μM and 2.85 ± 0.29 μM, respectively.
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Affiliation(s)
- Ting-Ting Fan
- Department of Development Technology of Marine Resources, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; (T.-T.F.); (H.-H.Z.); (F.-Z.Z.)
| | - Hui-Hui Zhang
- Department of Development Technology of Marine Resources, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; (T.-T.F.); (H.-H.Z.); (F.-Z.Z.)
| | - Yang-Hua Tang
- Department of Pharmacy, Graduate School, Hunan University of Chinese Medicine, Changsha 410208, China;
| | - Fan-Zhong Zhang
- Department of Development Technology of Marine Resources, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; (T.-T.F.); (H.-H.Z.); (F.-Z.Z.)
| | - Bing-Nan Han
- Department of Development Technology of Marine Resources, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; (T.-T.F.); (H.-H.Z.); (F.-Z.Z.)
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9
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Sutanto H, Laudy L, Clerx M, Dobrev D, Crijns HJ, Heijman J. Maastricht antiarrhythmic drug evaluator (MANTA): A computational tool for better understanding of antiarrhythmic drugs. Pharmacol Res 2019; 148:104444. [DOI: 10.1016/j.phrs.2019.104444] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 07/10/2019] [Accepted: 09/03/2019] [Indexed: 12/14/2022]
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10
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Tang YH, Wu J, Fan TT, Zhang HH, Gong XX, Cao ZY, Zhang J, Lin HW, Han BN. Chemical and biological study of aplysiatoxin derivatives showing inhibition of potassium channel Kv1.5. RSC Adv 2019; 9:7594-7600. [PMID: 35521179 PMCID: PMC9061199 DOI: 10.1039/c9ra00965e] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 02/25/2019] [Indexed: 11/21/2022] Open
Abstract
Three new aplysiatoxins, neo-debromoaplysiatoxin D (1), oscillatoxin E (2) and oscillatoxin F (3), accompanied by four known analogues (4–7), were identified from the marine cyanobacterium Lyngbya sp. Structural frames differ amongst these metabolites, and therefore we classified compounds 1 and 4–6 as aplysiatoxins as they possess 6/12/6 and 6/10/6 tricyclic ring systems featuring a macrolactone ring, and compounds 2, 3 and 7 as oscillatoxins that feature a hexane-tetrahydropyran in a spirobicyclic system. Bioactivity experiments showed that compounds 1 and 4–6 presented significant expression of phosphor-PKCδ whereas compounds 2, 5 and 7 showed the most potent blocking activity against potassium channel Kv1.5 with IC50 values of 0.79 ± 0.032 μM, 1.28 ± 0.080 μM and 1.47 ± 0.138 μM, respectively. Molecular docking analysis supplementing the binding interaction of oscillatoxin E (2) and oscillatoxin F (3) with Kv1.5 showed oscillatoxin E (2) with a strong binding affinity of −37.645 kcal mol−1 and oscillatoxin F (3) with a weaker affinity of −32.217 kcal mol−1, further supporting the experimental data. New aplysiatoxin derivative (oscillatoxin E) exhibiting potent blocking activity against potassium channel Kv1.5 is consistent with molecular docking analysis.![]()
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Affiliation(s)
- Yang-Hua Tang
- Research Center of Marine Biology and Natural Products
- College of Life Sciences and Medicine
- Zhejiang Sci-Tech University
- Hangzhou 310018
- China
| | - Jing Wu
- Department of Pathophysiology
- Shanghai Jiaotong University
- School of Medicine
- Shanghai 200025
- China
| | - Ting-Ting Fan
- Research Center of Marine Biology and Natural Products
- College of Life Sciences and Medicine
- Zhejiang Sci-Tech University
- Hangzhou 310018
- China
| | - Hui-Hui Zhang
- Research Center of Marine Biology and Natural Products
- College of Life Sciences and Medicine
- Zhejiang Sci-Tech University
- Hangzhou 310018
- China
| | - Xiao-Xia Gong
- Research Center of Marine Biology and Natural Products
- College of Life Sciences and Medicine
- Zhejiang Sci-Tech University
- Hangzhou 310018
- China
| | - Zheng-Yu Cao
- Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development
- China Pharmaceutical University
- Nanjing
- China
| | - Jian Zhang
- Department of Pathophysiology
- Shanghai Jiaotong University
- School of Medicine
- Shanghai 200025
- China
| | - Hou-Wen Lin
- Research Center for Marine Drugs
- State Key Laboratory of Oncogenes and Related Genes
- Department of Pharmacy
- Ren Ji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine
- Shanghai 200127
| | - Bing-Nan Han
- Research Center of Marine Biology and Natural Products
- College of Life Sciences and Medicine
- Zhejiang Sci-Tech University
- Hangzhou 310018
- China
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11
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Chen R, Chung SH. Inhibition of Voltage-Gated K + Channel Kv1.5 by Antiarrhythmic Drugs. Biochemistry 2018; 57:2704-2710. [PMID: 29652491 DOI: 10.1021/acs.biochem.8b00268] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular dynamics simulations are employed to determine the inhibitory mechanisms of three drugs, 5-(4-phenoxybutoxy)psoralen (PAP-1), vernakalant, and flecainide, on the voltage-gated K+ channel Kv1.5, a target for the treatment of cardiac arrhythmia. At neutral pH, PAP-1 is neutral, whereas the other two molecules carry one positive charge. We show that PAP-1 forms stable dimers in water, primarily through hydrophobic interactions between aromatic rings. All three molecules bind to the cavity between the Ile508 and Val512 residues from the four subunits of the channel. Once bound, the drug molecules are flexible, with the average root-mean-square fluctuation being between 2 and 3 Å, which is larger than the radius of gyration of a bulky amino acid. The presence of a monomeric PAP-1 causes the permeating K+ ion to dehydrate, thereby creating a significant energy barrier. In contrast, vernakalant blocks the ion permeation primarily via an electrostatic mechanism and, therefore, must be in the protonated and charged form to be effective.
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Affiliation(s)
- Rong Chen
- Research School of Biology , Australian National University , Acton , ACT 2601 , Australia
| | - Shin-Ho Chung
- Research School of Biology , Australian National University , Acton , ACT 2601 , Australia
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12
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Capucci A, Cipolletta L, Guerra F, Giannini I. Emerging pharmacotherapies for the treatment of atrial fibrillation. Expert Opin Emerg Drugs 2018; 23:25-36. [PMID: 29508636 DOI: 10.1080/14728214.2018.1446941] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION The main aim of current research on the field of atrial fibrillation (AF) treatment is to find new antiarrhythmic drugs with less side effects. Areas covered: Dronedarone and vernakalant showed promising result in term of efficacy and safety in selected patients. Ranolazine and colchicine are obtaining a role as a potential antiarrhythmic drug. Ivabradine is used in experimental studies for the rate control of AF. Moreover, new compounds (vanoxerine, moxonidine, budiodarone) are still under investigation. Monoclonal antibodies or selective antagonist of potassium channel are under investigation for long term maintenance of sinus rhythm. Clinical evidence and new pharmacological investigation on new drugs will be accurately reviewed in this article. Expert opinion: Dronedarone use is not recommended in patients with symptomatic heart failure (HF), NYHA class III-IV, depressed ventricular function and permanent AF, especially in patients assuming a concomitant therapy with digoxin. Vernakalant had superior efficacy than amiodarone, flecainide and propafenone in single studies and similar efficacy to direct current cardioversion. Several of the developing drugs examined in this paper show an interesting potential, in particular the research on selective ionic channel inhibition and on compounds which reduce the inflammation state, especially after ablation or surgery.
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Affiliation(s)
- Alessandro Capucci
- a Department of Scienze Cardiovascolari , Clinica di Cardiologia Universita' Politecnica delle Marche - Scienze Cardiovascolari , Ancona , Italy
| | - Laura Cipolletta
- a Department of Scienze Cardiovascolari , Clinica di Cardiologia Universita' Politecnica delle Marche - Scienze Cardiovascolari , Ancona , Italy
| | - Federico Guerra
- a Department of Scienze Cardiovascolari , Clinica di Cardiologia Universita' Politecnica delle Marche - Scienze Cardiovascolari , Ancona , Italy
| | - Irene Giannini
- a Department of Scienze Cardiovascolari , Clinica di Cardiologia Universita' Politecnica delle Marche - Scienze Cardiovascolari , Ancona , Italy
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13
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Interactions of Propofol With Human Voltage-gated Kv1.5 Channel Determined by Docking Simulation and Mutagenesis Analyses. J Cardiovasc Pharmacol 2018; 71:10-18. [DOI: 10.1097/fjc.0000000000000538] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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14
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Barajas-Martinez H, Goodrow RJ, Hu D, Patel P, Desai M, Panama BK, Treat JA, Aistrup GL, Cordeiro JM. Biophysical and molecular comparison of sodium current in cells isolated from canine atria and pulmonary vein. Pflugers Arch 2017; 469:703-712. [PMID: 28243733 DOI: 10.1007/s00424-017-1956-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 02/08/2017] [Accepted: 02/10/2017] [Indexed: 11/25/2022]
Abstract
The collar of the pulmonary vein (PV) is the focal point for the initiation of atrial arrhythmias, but the mechanisms underlying how PV cells differ from neighboring left atrial tissue are unclear. We examined the biophysical and molecular properties of INa in cells isolated from the canine pulmonary sleeve and compared the properties to left atrial tissue. PV and left atrial myocytes were isolated and patch clamp techniques were used to record INa. Action potential recordings from either tissue type were made using high-resistance electrodes. mRNA was determined using quantitative RT-PCR and proteins were determined by Western blot. Analysis of the action potential characteristics showed that PV tissue had a lower Vmax compared with left atrial tissue. Fast INa showed that current density was slightly lower in PV cells compared with LA cells (-96 ± 18.7 pA/pF vs. -120 ± 6.7 pA/pF, respectively, p < 0.05). The recovery from inactivation of INa in PV cells was slightly slower but no marked difference in steady-state inactivation was noted. Analysis of late INa during a 225-ms pulse showed that late INa was significantly smaller in PV cells compared to LA cells at all measured time points into the pulse. These results suggest PV cells have lower density of both peak and late INa. Molecular analysis of Nav1.5 and the four beta subunits showed lower levels of Nav1.5 as well as Navβ1 subunits, confirming the biophysical findings. These data show that a lower density of INa may lead to depression of excitability and predispose the PV collar to re-entrant circuits under pathophysiological conditions.
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Affiliation(s)
- Hector Barajas-Martinez
- Department of Experimental Cardiology, Masonic Medical Research Laboratory, 2150 Bleecker Street, Utica, NY, 13501, USA
| | - Robert J Goodrow
- Department of Experimental Cardiology, Masonic Medical Research Laboratory, 2150 Bleecker Street, Utica, NY, 13501, USA
| | - Dan Hu
- Department of Experimental Cardiology, Masonic Medical Research Laboratory, 2150 Bleecker Street, Utica, NY, 13501, USA
| | - Payal Patel
- Department of Experimental Cardiology, Masonic Medical Research Laboratory, 2150 Bleecker Street, Utica, NY, 13501, USA
| | - Mayurika Desai
- Department of Experimental Cardiology, Masonic Medical Research Laboratory, 2150 Bleecker Street, Utica, NY, 13501, USA
| | - Brian K Panama
- Department of Experimental Cardiology, Masonic Medical Research Laboratory, 2150 Bleecker Street, Utica, NY, 13501, USA
| | - Jacqueline A Treat
- Department of Experimental Cardiology, Masonic Medical Research Laboratory, 2150 Bleecker Street, Utica, NY, 13501, USA
| | - Gary L Aistrup
- Department of Experimental Cardiology, Masonic Medical Research Laboratory, 2150 Bleecker Street, Utica, NY, 13501, USA
| | - Jonathan M Cordeiro
- Department of Experimental Cardiology, Masonic Medical Research Laboratory, 2150 Bleecker Street, Utica, NY, 13501, USA.
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15
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Wu W, Sanguinetti MC. Molecular Basis of Cardiac Delayed Rectifier Potassium Channel Function and Pharmacology. Card Electrophysiol Clin 2016; 8:275-84. [PMID: 27261821 DOI: 10.1016/j.ccep.2016.01.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Human cardiomyocytes express 3 distinct types of delayed rectifier potassium channels. Human ether-a-go-go-related gene (hERG) channels conduct the rapidly activating current IKr; KCNQ1/KCNE1 channels conduct the slowly activating current IKs; and Kv1.5 channels conduct an ultrarapid activating current IKur. Here the authors provide a general overview of the mechanistic and structural basis of ion selectivity, gating, and pharmacology of the 3 types of cardiac delayed rectifier potassium ion channels. Most blockers bind to S6 residues that line the central cavity of the channel, whereas activators interact with the channel at 4 symmetric binding sites outside the cavity.
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Affiliation(s)
- Wei Wu
- Department of Medicine, Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, 95 South 2000 East, Salt Lake City, UT 84112, USA
| | - Michael C Sanguinetti
- Department of Medicine, Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, 95 South 2000 East, Salt Lake City, UT 84112, USA.
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16
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Abstract
The voltage gated Kv1.5 channels conduct the ultrarapid delayed rectifier current (IKur) and play critical role in repolarization of action potential duration. It is the most rapidly activated channel and has very little or no inactivated states. In human cardiac cells, these channels are expressed more extensively in atrial myocytes than ventricle. From the evidences of its localization and functions, Kv1.5 has been declared a selective drug target for the treatment of atrial fibrillation (AF). In this present study, we have tried to identify the rapidly activating property of Kv1.5 and studied its mode of inhibition using molecular modeling, docking, and simulation techniques. Channel in open conformation is found to be stabilized quickly within the dipalmitoylphosphatidylcholine membrane, whereas most of the secondary structure elements were lost in closed state conformation. The obvious reason behind its ultra-rapid property is possibly due to the amino acid alteration in S4-S5 linker; the replacement of Lysine by Glutamine and vice versa. The popular published drugs as well as newly identified lead molecules were able to inhibit the Kv1.5 in a very similar pattern, mainly through the nonpolar interactions, and formed sable complexes. V512 is found as the main contributor for the interaction along with the other important residues such as V505, I508, A509, V512, P513, and V516. Furthermore, two screened novel compounds show surprisingly better inhibitory potency and can be considered for the future perspective of antiarrhythmic survey.
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Affiliation(s)
- Rajabrata Bhuyan
- a BIF Centre, Department of Biochemistry & Biophysics , University of Kalyani , Nadia, Kalyani 741235 , West Bengal , India
| | - Alpana Seal
- b Department of Biochemistry & Biophysics , University of Kalyani , Nadia, Kalyani 741235 , West Bengal , India
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17
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Liu J, Laksman Z, Backx PH. The electrophysiological development of cardiomyocytes. Adv Drug Deliv Rev 2016; 96:253-73. [PMID: 26788696 DOI: 10.1016/j.addr.2015.12.023] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 12/23/2015] [Accepted: 12/31/2015] [Indexed: 02/07/2023]
Abstract
The generation of human cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs) has become an important resource for modeling human cardiac disease and for drug screening, and also holds significant potential for cardiac regeneration. Many challenges remain to be overcome however, before innovation in this field can translate into a change in the morbidity and mortality associated with heart disease. Of particular importance for the future application of this technology is an improved understanding of the electrophysiologic characteristics of CMs, so that better protocols can be developed and optimized for generating hPSC-CMs. Many different cell culture protocols are currently utilized to generate CMs from hPSCs and all appear to yield relatively “developmentally” immature CMs with highly heterogeneous electrical properties. These hPSC-CMs are characterized by spontaneous beating at highly variable rates with a broad range of depolarization-repolarization patterns, suggestive of mixed populations containing atrial, ventricular and nodal cells. Many recent studies have attempted to introduce approaches to promote maturation and to create cells with specific functional properties. In this review, we summarize the studies in which the electrical properties of CMs derived from stem cells have been examined. In order to place this information in a useful context, we also review the electrical properties of CMs as they transition from the developing embryo to the adult human heart. The signal pathways involved in the regulation of ion channel expression during development are also briefly considered.
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18
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Matassini MV, Guerra F, Scappini L, Scappini L, Urbinati A, Capucci A. New anthyarrhythmic drugs for atrial fibrillation. Future Cardiol 2015; 11:705-17. [PMID: 26631497 DOI: 10.2217/fca.15.69] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Atrial fibrillation (AF) is a common arrhythmia associated with increased mortality and morbidity. Different studies have shown no significant difference between rhythm and rate control strategies in terms of mortality. Moreover, the use of antiarrhythmic drugs is afflicted by cardiac and extracardiac toxicity and related costs of hospitalization. Nevertheless, some patients require a rhythm-control strategy and new anti-AF agents are being sought. Only few novel agents showed promising results in term of efficacy and safety. Dronedarone and vernakalant are two of these compounds, respectively introduced for the chronic and acute rhythm control of AF. This article will review pharmacology and clinical evidence on the use of dronedarone and vernakalant and will mention currently investigated new antiarrhythmic drugs.
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Affiliation(s)
- Maria Vittoria Matassini
- Cardiology & Arrhythmology Clinic, 'Ospedali Riuniti' University Hospital, Marche Polytechnic University, Ancona, Italy
| | - Federico Guerra
- Cardiology & Arrhythmology Clinic, 'Ospedali Riuniti' University Hospital, Marche Polytechnic University, Ancona, Italy
| | | | - Loren Scappini
- Cardiology & Arrhythmology Clinic, 'Ospedali Riuniti' University Hospital, Marche Polytechnic University, Ancona, Italy
| | - Alessia Urbinati
- Cardiology & Arrhythmology Clinic, 'Ospedali Riuniti' University Hospital, Marche Polytechnic University, Ancona, Italy
| | - Alessandro Capucci
- Cardiology & Arrhythmology Clinic, 'Ospedali Riuniti' University Hospital, Marche Polytechnic University, Ancona, Italy
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19
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Bai J, Ding W, Kojima A, Seto T, Matsuura H. Putative binding sites for arachidonic acid on the human cardiac Kv 1.5 channel. Br J Pharmacol 2015; 172:5281-92. [PMID: 26292661 PMCID: PMC5341216 DOI: 10.1111/bph.13314] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 08/01/2015] [Accepted: 08/18/2015] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND AND PURPOSE In human heart, the Kv 1.5 channel contributes to repolarization of atrial action potentials. This study examined the electrophysiological and molecular mechanisms underlying arachidonic acid (AA)-induced inhibition of the human Kv 1.5 (hKv 1.5) channel. EXPERIMENTAL APPROACH Site-directed mutagenesis was conducted to mutate amino acids that reside within the pore domain of the hKv 1.5 channel. Whole-cell patch-clamp method was used to record membrane currents through wild type and mutant hKv 1.5 channels heterologously expressed in CHO cells. Computer docking simulation was conducted to predict the putative binding site(s) of AA in an open-state model of the Kv 1.5 channel. KEY RESULTS The hKv 1.5 current was minimally affected at the onset of depolarization but was progressively reduced during depolarization by the presence of AA, suggesting that AA acts as an open-channel blocker. AA itself affected the channel at extracellular sites independently of its metabolites and signalling pathways. The blocking effect of AA was attenuated at pH 8.0 but not at pH 6.4. The blocking action of AA developed rather rapidly by co-expression of Kv β1.3. The AA-induced block was significantly attenuated in H463C, T480A, R487V, I502A, I508A, V512A and V516A, but not in T462C, A501V and L510A mutants of the hKv 1.5 channel. Docking simulation predicted that H463, T480, R487, I508, V512 and V516 are potentially accessible for interaction with AA. CONCLUSIONS AND IMPLICATIONS AA itself interacts with multiple amino acids located in the pore domain of the hKv 1.5 channel. These findings may provide useful information for future development of selective blockers of hKv 1.5 channels.
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Affiliation(s)
- Jia‐Yu Bai
- Department of PhysiologyShiga University of Medical ScienceOtsuJapan
| | - Wei‐Guang Ding
- Department of PhysiologyShiga University of Medical ScienceOtsuJapan
| | - Akiko Kojima
- Department of AnesthesiologyShiga University of Medical ScienceOtsuJapan
| | - Tomoyoshi Seto
- Department of AnesthesiologyShiga University of Medical ScienceOtsuJapan
| | - Hiroshi Matsuura
- Department of PhysiologyShiga University of Medical ScienceOtsuJapan
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20
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Kojima A, Ito Y, Ding WG, Kitagawa H, Matsuura H. Interaction of propofol with voltage-gated human Kv1.5 channel through specific amino acids within the pore region. Eur J Pharmacol 2015; 764:622-632. [PMID: 26256861 DOI: 10.1016/j.ejphar.2015.08.007] [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: 06/20/2015] [Accepted: 08/05/2015] [Indexed: 12/25/2022]
Abstract
The intravenous anesthetic propofol affects the function of a diversity of ligand-gated and voltage-gated ion channels. However, there is little information as to whether propofol directly interacts with voltage-gated ion channel proteins to modulate their functions. The Kv1.5 channel is activated by membrane depolarization during action potentials and contributes to atrial repolarization in the human heart. This study was undertaken to examine the effect of propofol on voltage-gated human Kv1.5 (hKv1.5) channel and to elucidate the underlying molecular determinants. Site-directed mutagenesis was carried out through six amino acids that reside within the pore domain of hKv1.5 channel. Whole-cell patch-clamp technique was used to record membrane currents through the wild type and mutant hKv1.5 channels heterologously expressed in Chinese hamster ovary cells. Propofol (≥5 μM) reversibly and concentration-dependently (IC50 of 49.3±9.4 μM; n=6) blocked hKv1.5 current. Propofol-induced block of hKv1.5 current gradually progressed during depolarizing voltage-clamp steps and was enhanced by higher frequency of activation, consistent with a preferential block of the channels in their open state. The degree of current block by propofol was significantly attenuated in T480A, I502A, I508A and V516A, but not in H463C and L510A mutants of hKv1.5 channel. Thus, several amino acids near the selectivity filter (Thr480) or within S6 (Ile502, Ile508 and Val516) are found to be critically involved in the blocking action of propofol. This study provides the first evidence suggesting that direct interaction with specific amino acids underlies the blocking action of propofol on voltage-gated hKv1.5 channel.
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Affiliation(s)
- Akiko Kojima
- Department of Anesthesiology, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan.
| | - Yuki Ito
- Department of Anesthesiology, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan
| | - Wei-Guang Ding
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan
| | - Hirotoshi Kitagawa
- Department of Anesthesiology, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan
| | - Hiroshi Matsuura
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan.
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21
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Melgari D, Zhang Y, El Harchi A, Dempsey CE, Hancox JC. Molecular basis of hERG potassium channel blockade by the class Ic antiarrhythmic flecainide. J Mol Cell Cardiol 2015; 86:42-53. [PMID: 26159617 PMCID: PMC4564290 DOI: 10.1016/j.yjmcc.2015.06.021] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/19/2015] [Accepted: 06/30/2015] [Indexed: 11/02/2022]
Abstract
The class Ic antiarrhythmic drug flecainide inhibits KCNH2-encoded "hERG" potassium channels at clinically relevant concentrations. The aim of this study was to elucidate the underlying molecular basis of this action. Patch clamp recordings of hERG current (IhERG) were made from hERG expressing cells at 37°C. Wild-type (WT) IhERG was inhibited with an IC50 of 1.49μM and this was not significantly altered by reversing the direction of K(+) flux or raising external [K(+)]. The use of charged and uncharged flecainide analogues showed that the charged form of the drug accesses the channel from the cell interior to produce block. Promotion of WT IhERG inactivation slowed recovery from inhibition, whilst the N588K and S631A attenuated-inactivation mutants exhibited IC50 values 4-5 fold that of WT IhERG. The use of pore-helix/selectivity filter (T623A, S624A V625A) and S6 helix (G648A, Y652A, F656A) mutations showed <10-fold shifts in IC50 for all but V625A and F656A, which respectively exhibited IC50s 27-fold and 142-fold their WT controls. Docking simulations using a MthK-based homology model suggested an allosteric effect of V625A, since in low energy conformations flecainide lay too low in the pore to interact directly with that residue. On the other hand, the molecule could readily form π-π stacking interactions with aromatic residues and particularly with F656. We conclude that flecainide accesses the hERG channel from the cell interior on channel gating, binding low in the inner cavity, with the S6 F656 residue acting as a principal binding determinant.
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Affiliation(s)
- Dario Melgari
- School of Physiology & Pharmacology, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Yihong Zhang
- School of Physiology & Pharmacology, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Aziza El Harchi
- School of Physiology & Pharmacology, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Christopher E Dempsey
- School of Biochemistry, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Jules C Hancox
- School of Physiology & Pharmacology, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK.
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22
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Guerra F, Matassini MV, Scappini L, Urbinati A, Capucci A. Intravenous vernakalant for the rapid conversion of recent onset atrial fibrillation: systematic review and meta-analysis. Expert Rev Cardiovasc Ther 2014; 12:1067-75. [PMID: 25096598 DOI: 10.1586/14779072.2014.943662] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Atrial fibrillation is the most common cardiac arrhythmia and is associated with increased mortality and morbidity. Conversion to sinus rhythm is usually appropriate in patients with acute, symptomatic atrial fibrillation in order to reduce symptoms and prevent complications. Electrical cardioversion is the most used and widespread technique, but requires deep sedation and a fasting state. Pharmacological alternatives are burdened by a delayed onset of action and potential proarrhythmic effects. Therefore, new therapeutic options are being sought. Among those, vernakalant, showed a good efficacy profile and a short onset of action, but with conflicting evidence regarding potential serious adverse events. This drug profile will summarize the pharmacology behind this new drug and review recent evidence in terms of safety and efficacy.
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Affiliation(s)
- Federico Guerra
- Cardiology Clinic, University Hospital "Ospedali Riuniti", Marche Polytechnic University, Via Conca 71, 60126, Ancona, Italy
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23
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Tinker A, Harmer SC. K+channels in the heart: new insights and therapeutic implications. Expert Rev Clin Pharmacol 2014; 3:305-19. [DOI: 10.1586/ecp.10.14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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24
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Tikhonov DB, Zhorov BS. Homology modeling of Kv1.5 channel block by cationic and electroneutral ligands. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:978-87. [PMID: 24316168 DOI: 10.1016/j.bbamem.2013.11.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 11/12/2013] [Accepted: 11/26/2013] [Indexed: 01/05/2023]
Abstract
The inner pore of potassium channels is targeted by many ligands of intriguingly different chemical structures. Previous studies revealed common and diverse characteristics of action of ligands including cooperativity of ligand binding, voltage- and use-dependencies, and patterns of ligand-sensing residues. Not all these data are rationalized in published models of ligand-channel complexes. Here we have used energy calculations with experimentally defined constraints to dock flecainide, ICAGEN-4, benzocaine, vernakalant, and AVE0118 into the inner pore of Kv1.5 channel. We arrived at ligand-binding models that suggest possible explanations for different values of the Hill coefficient, different voltage dependencies of ligands action, and effects of mutations of residues in subunit interfaces. Two concepts were crucial to build the models. First, the inner-pore block of a potassium channel requires a cationic "blocking particle". A ligand, which lacks a positively charged group, blocks the channel in a complex with a permeant ion. Second, hydrophobic moieties of a flexible ligand have a tendency to bind in hydrophobic subunit interfaces.
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Affiliation(s)
- Denis B Tikhonov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia.
| | - Boris S Zhorov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia; Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
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Zhorov BS, Tikhonov DB. Ligand action on sodium, potassium, and calcium channels: role of permeant ions. Trends Pharmacol Sci 2013; 34:154-61. [PMID: 23375737 DOI: 10.1016/j.tips.2013.01.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Revised: 01/04/2013] [Accepted: 01/07/2013] [Indexed: 12/22/2022]
Abstract
Ion channels are targets for many naturally occurring toxins and small-molecule drugs. Despite great progress in the X-ray crystallography of ion channels, we still do not have a complete understanding of the atomistic mechanisms of channel modulation by ligands. In particular, the importance of the simultaneous interaction of permeant ions with the ligand and the channel protein has not been the focus of much attention. Considering these interactions often allows one to rationalize the highly diverse experimental data within the framework of relatively simple structural models. This has been illustrated in earlier studies on the action of local anesthetics, sodium channel activators, as well as blockers of potassium and calcium channels. Here, we discuss the available data with a view to understanding the use-, voltage-, and current carrying cation-dependence of the ligand action, paradoxes in structure--activity relationships, and effects of mutations in these ion channels.
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Affiliation(s)
- Boris S Zhorov
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, L8S 4K1, Canada.
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Wettwer E, Christ T, Endig S, Rozmaritsa N, Matschke K, Lynch JJ, Pourrier M, Gibson JK, Fedida D, Knaut M, Ravens U. The new antiarrhythmic drug vernakalant: ex vivo study of human atrial tissue from sinus rhythm and chronic atrial fibrillation. Cardiovasc Res 2013; 98:145-54. [PMID: 23341576 DOI: 10.1093/cvr/cvt006] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS Vernakalant is a newly developed antiarrhythmic drug against atrial fibrillation (AF). However, its electrophysiological actions on human myocardium are unknown. METHODS AND RESULTS Action potentials (APs) and ion currents were recorded in right atrial trabeculae and cardiomyocytes from patients in sinus rhythm (SR) and chronic AF. Vernakalant prolonged early repolarization in SR and AF, but late only in AF. AP amplitude (APA) and dV/dtmax were reduced in a concentration- and frequency-dependent manner with IC50 < 10 µM at >3 Hz. Effective refractory period was increased more than action potential duration (APD) in SR and AF. INa was blocked with IC50s of 95 and 84 µM for SR and AF, respectively (0.5 Hz). Vernakalant did not reduce outward potassium currents compared with time-matched controls. However, area under the current-time curve was reduced due to acceleration of current decline with IC50s of 19 and 12 µM for SR and AF, respectively. Vernakalant had less effect on APD than the IKr blocker E-4031, blocked IK,ACh, and had a small inhibitory effect on IK1 at 30 µM. L-Type Ca(2+) currents (SR) were reduced with IC50 of 84 µM. CONCLUSION Rate-dependent block of Na(+) channels represents the main antiarrhythmic mechanism of vernakalant in the fibrillating atrium. Open channel block of early transient outward currents and IK,ACh could also contribute.
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Affiliation(s)
- Erich Wettwer
- Department of Pharmacology and Toxicology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, Fetscherstraße 74, Dresden D-01307, Germany.
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Abstract
Atrial fibrillation is the most common type of cardiac arrhythmia, and is responsible for substantial morbidity and mortality in the general population. Current treatments have moderate efficacy and considerable risks, especially of pro-arrhythmia, highlighting the need for new therapeutic strategies. In recent years, substantial efforts have been invested in developing novel treatments that target the underlying molecular determinants of atrial fibrillation, and several new compounds are under development. This Review focuses on the mechanistic rationale for the development of new anti-atrial fibrillation drugs, on the molecular and structural motifs that they target and on the results obtained so far in experimental and clinical studies.
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Sicouri S, Pourrier M, Gibson JK, Lynch JJ, Antzelevitch C. Comparison of electrophysiological and antiarrhythmic effects of vernakalant, ranolazine, and sotalol in canine pulmonary vein sleeve preparations. Heart Rhythm 2012; 9:422-9. [PMID: 22019863 PMCID: PMC3288874 DOI: 10.1016/j.hrthm.2011.10.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 10/17/2011] [Indexed: 12/19/2022]
Abstract
BACKGROUND Vernakalant (VER) is a relatively atrial-selective antiarrhythmic drug capable of blocking potassium and sodium currents in a frequency- and voltage-dependent manner. Ranolazine (RAN) is a sodium-channel blocker shown to exert antiarrhythmic effects in pulmonary vein (PV) sleeves. dl-Sotalol (SOT) is a β-blocker commonly used in the rhythm-control treatment of atrial fibrillation. This study evaluated the electrophysiological and antiarrhythmic effects of VER, RAN, and SOT in canine PV sleeve preparations in a blinded fashion. METHODS Transmembrane action potentials were recorded from canine superfused PV sleeve preparations exposed to VER (n = 6), RAN (n = 6), and SOT (n = 6). Delayed afterdepolarizations were induced in the presence of isoproterenol and high-calcium concentrations by periods of rapid pacing. RESULTS In PV sleeves, VER, RAN, and SOT (3-30 μM) produced small (10-15 ms) increases in action potential duration. The effective refractory period, diastolic threshold of excitation, and the shortest S(1)-S(1) cycle length permitting 1:1 activation were significantly increased by VER and RAN in a rate- and concentration-dependent manner. VER and RAN significantly reduced V(max) in a concentration- and rate-dependent manner. SOT did not significantly affect the effective refractory period, V(max), diastolic threshold of excitation, or the shortest S(1)-S(1) cycle length permitting 1:1 activation. All 3 agents (3-30 μM) suppressed delayed afterdepolarization-mediated triggered activity induced by isoproterenol and high calcium. CONCLUSIONS In canine PV sleeves, the effects of VER and RAN were similar and largely characterized by concentration- and rate-dependent depression of sodium-channel-mediated parameters, which were largely unaffected by SOT. All 3 agents demonstrated an ability to effectively suppress delayed afterdepolarization-induced triggers of atrial arrhythmia.
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Herrington J, Solly K, Ratliff KS, Li N, Zhou YP, Howard A, Kiss L, Garcia ML, McManus OB, Deng Q, Desai R, Xiong Y, Kaczorowski GJ. Identification of novel and selective Kv2 channel inhibitors. Mol Pharmacol 2011; 80:959-64. [PMID: 21948463 DOI: 10.1124/mol.111.074831] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Identification of selective ion channel inhibitors represents a critical step for understanding the physiological role that these proteins play in native systems. In particular, voltage-gated potassium (K(V)2) channels are widely expressed in tissues such as central nervous system, pancreas, and smooth muscle, but their particular contributions to cell function are not well understood. Although potent and selective peptide inhibitors of K(V)2 channels have been characterized, selective small molecule K(V)2 inhibitors have not been reported. For this purpose, high-throughput automated electrophysiology (IonWorks Quattro; Molecular Devices, Sunnyvale, CA) was used to screen a 200,000-compound mixture (10 compounds per sample) library for inhibitors of K(V)2.1 channels. After deconvolution of 190 active samples, two compounds (A1 and B1) were identified that potently inhibit K(V)2.1 and the other member of the K(V)2 family, K(V)2.2 (IC(50), 0.1-0.2 μM), and that possess good selectivity over K(V)1.2 (IC(50) >10 μM). Modeling studies suggest that these compounds possess a similar three-dimensional conformation. Compounds A1 and B1 are >10-fold selective over Na(V) channels and other K(V) channels and display weak activity (5-9 μM) on Ca(V) channels. The biological activity of compound A1 on native K(V)2 channels was confirmed in electrophysiological recordings of rat insulinoma cells, which are known to express K(V)2 channels. Medicinal chemistry efforts revealed a defined structure-activity relationship and led to the identification of two compounds (RY785 and RY796) without significant Ca(V) channel activity. Taken together, these newly identified channel inhibitors represent important tools for the study of K(V)2 channels in biological systems.
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Affiliation(s)
- James Herrington
- Department of Ion Channels, Merck Research Laboratories, Rahway, New Jersey 07065, USA
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Wu HJ, Wu W, Sun HY, Qin GW, Wang HB, Wang P, Yalamanchili HK, Wang J, Tse HF, Lau CP, Vanhoutte PM, Li GR. Acacetin causes a frequency- and use-dependent blockade of hKv1.5 channels by binding to the S6 domain. J Mol Cell Cardiol 2011; 51:966-73. [PMID: 21906601 DOI: 10.1016/j.yjmcc.2011.08.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 08/01/2011] [Accepted: 08/21/2011] [Indexed: 11/18/2022]
Abstract
We have demonstrated that the natural flavone acacetin selectively inhibits ultra-rapid delayed rectifier potassium current (I(Kur)) in human atria. However, molecular determinants of this ion channel blocker are unknown. The present study was designed to investigate the molecular determinants underlying the ability of acacetin to block hKv1.5 channels (coding I(Kur)) in human atrial myocytes using the whole-cell patch voltage-clamp technique to record membrane current in HEK 293 cells stably expressing the hKv1.5 gene or transiently expressing mutant hKv1.5 genes generated by site-directed mutagenesis. It was found that acacetin blocked hKv1.5 channels by binding to both closed and open channels. The blockade of hKv1.5 channels by acacetin was use- and frequency-dependent, and the IC(50) of acacetin for inhibiting hKv1.5 was 3.5, 3.1, 2.9, 2.1, and 1.7μM, respectively, at 0.2, 0.5, 1, 3, and 4Hz. The mutagenesis study showed that the hKv1.5 mutants V505A, I508A, and V512A in the S6-segment remarkably reduced the channel blocking properties by acacetin (IC(50), 29.5μM for V505A, 19.1μM for I508A, and 6.9μM for V512A). These results demonstrate the novel information that acacetin mainly blocks open hKv1.5 channels by binding to their S6 domain. The use- and rate-dependent blocking of hKv1.5 by acacetin is beneficial for anti-atrial fibrillation.
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Affiliation(s)
- Hui-Jun Wu
- Department and Medicine, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Pokfulam, Hong Kong SAR, China
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Abstract
Intravenous vernakalant (Brinavess®) is an atrial-repolarization-delaying agent that is currently approved in the EU for the rapid conversion of recent-onset atrial fibrillation to sinus rhythm. Vernakalant blocks atrial-specific potassium and sodium ion channels, prolonging atrial refractory periods and rate-dependently slowing atrial conduction, without promoting ventricular arrhythmia. In pivotal, randomized, phase III trials, intravenous vernakalant 3 mg /kg administered as a 10-minute infusion, followed by a 2 mg/kg 10-minute infusion after 15 minutes if atrial fibrillation persisted, was effective in the rapid termination of recent-onset atrial fibrillation in nonsurgical patients (≥ 3 hours' to ≤ 7 days' duration) and in those with postoperative atrial fibrillation (3-72 hours' duration) following cardiac surgery. Conversion to sinus rhythm occurred rapidly following infusion of vernakalant, with the majority of patients converting after the first dose, and conversion to sinus rhythm was generally associated with a rapid resolution of symptoms. These antiarrhythmic effects of vernakalant were durable, with most responders remaining in sinus rhythm 24 hours after treatment initiation. In nonsurgical patients with recent-onset atrial fibrillation of 3-48 hours' duration, vernakalant was more effective than intravenous amiodarone, with a significantly higher proportion of patients converting to sinus rhythm within the first 90 minutes of treatment. Vernakalant was generally well tolerated in clinical trials, with most adverse events being of mild or moderate severity and not treatment limiting. Increases in QRS or QT intervals were transient, and there was no increased incidence of ventricular arrhythmia observed with vernakalant compared with placebo. Therefore, intravenous vernakalant provides an effective option for the management of recent-onset atrial fibrillation.
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Ravens U, Wettwer E. Ultra-rapid delayed rectifier channels: molecular basis and therapeutic implications. Cardiovasc Res 2010; 89:776-85. [DOI: 10.1093/cvr/cvq398] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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Yang Q, Fedida D, Xu H, Wang B, Du L, Wang X, Li M, You Q. Structure-based virtual screening and electrophysiological evaluation of new chemotypes of K(v)1.5 channel blockers. ChemMedChem 2010; 5:1353-8. [PMID: 20540065 DOI: 10.1002/cmdc.201000162] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Atrial fibrillation (AF) is the most prevalent nonfatal cardiac rhythm disorder associated with an increased risk of heart failure and stroke. Considering the ventricular side effects induced by anti-arrhythmic agents in current use, K(v)1.5 channel blockers have attracted a great deal of deliberation owing to their selective actions on atrial electrophysiology. Herein we report new chemotypes of K(v)1.5 channel blockers that were identified through a combination of structure-based virtual screening and in silico druglike property prediction including six scoring functions, as well as electrophysiological evaluation. Among them, five of the 18 compounds exhibited >50 % blockade ratio at 10 microM, and have structural features different from conventional K(v)1.5 channel blockers. These novel scaffolds could serve as hits for further optimization and SAR studies for the discovery of selective agents to treat AF.
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Affiliation(s)
- Qian Yang
- Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing, Jiangsu, China
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Li Y, Tu D, Xiao H, Du Y, Zou A, Liao Y, Dong S. Aconitine blocks HERG and Kv1.5 potassium channels. JOURNAL OF ETHNOPHARMACOLOGY 2010; 131:187-195. [PMID: 20600762 DOI: 10.1016/j.jep.2010.06.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 06/08/2010] [Accepted: 06/10/2010] [Indexed: 05/29/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Aconitum has been widely used to treat various diseases in China for a long time. However, improper use of this drug results in severe intoxication. Aconitine (ACO), a diterpenoid alkaloid from aconitum, mainly contributes to cardio-toxic effects of aconitum and has also been commonly known to induce arrhythmias in animal models. However, its pro-arrhythmic mechanisms are not clear. AIM OF THE STUDY The effects of ACO on HERG and Kv1.5 channels were investigated. MATERIALS AND METHODS HERG and Kv1.5 channels were expressed in Xenopus laevis oocytes, and the resulting currents were recorded using a two-microelectrode voltage clamp technique. RESULTS In HERG channels, ACO exhibited a blockade in a voltage- and time-dependent manner. The blockade was enhanced by further activation of currents, which were consistent with an open-channel blockade. In Kv1.5 channels, ACO produced a voltage-, time-, and frequency-dependent inhibition. The blockade was enhanced by higher rates of stimulation, consistent with preferential binding of the drug to the open state. In addition, ACO blocked Kv1.5 and HERG channels in a concentration-dependent manner with an IC(50) of 0.796+/-0.123 and 1.801+/-0.332 microM, respectively. CONCLUSIONS ACO blocks HERG and Kv1.5 potassium channels in the open state. Blockade of potassium channels, particular the HERG channel, may be one of the important mechanisms of how ACO induces arrhythmias.
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Affiliation(s)
- Yifu Li
- Ion Channelopathy Research Center, Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, PR China
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Weeke P, Andersson C, Brendorp B, Torp-Pedersen C. Vernakalant (RSD1235) in the management of atrial fibrillation: a review of pharmacological properties, clinical efficacy and safety. Future Cardiol 2010; 4:559-67. [PMID: 19804350 DOI: 10.2217/14796678.4.6.559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Vernakalant (RSD1235) is a novel antiarrhythmic agent for conversion of rapid onset atrial fibrillation (AF). It is an atria-selective multichannel ion blocker (blocks I(Kur), I(Na), I(Ca, L), I(to) and I(Kr)), with a small effect on ventricular repolarization. In clinical Phase II and III studies, vernakalant was moderately (approximately 50%) effective in converting AF of short duration (< 7 days), and effective (approximately 70-80%) in converting AF of less than 72 h, but was not effective in converting long duration AF (>7 days) or atrial flutter. Vernakalant seems to have only a small proarrhythmic effect, with no reported cases of torsades de pointes in direct relation to vernakalant administration in Phase II and III studies. Overall, there are few reported serious adverse events.
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Affiliation(s)
- Peter Weeke
- Dept Cardiology, Gentofte Hospital, University of Copenhagen, Niels Andersens Vej 65, 2900 Hellerup, Denmark.
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Molecular determinants of Kv1.5 channel block by diphenyl phosphine oxide-1. J Mol Cell Cardiol 2010; 48:1111-20. [DOI: 10.1016/j.yjmcc.2010.02.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 02/09/2010] [Accepted: 02/12/2010] [Indexed: 11/18/2022]
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Moreno-Galindo EG, Barrio-Echavarría GF, Vásquez JC, Decher N, Sachse FB, Tristani-Firouzi M, Sánchez-Chapula JA, Navarro-Polanco RA. Molecular basis for a high-potency open-channel block of Kv1.5 channel by the endocannabinoid anandamide. Mol Pharmacol 2010; 77:751-8. [PMID: 20133392 DOI: 10.1124/mol.109.063008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The endocannabinoid, N-arachidonoylethanolamine (anandamide; AEA) is known to interact with voltage-gated K(+) (Kv) channels in a cannabinoid receptor-independent manner. AEA modulates the functional properties of Kv channels, converting channels with slowly inactivating current into apparent fast inactivation. In this study, we characterize the mechanism of action and binding site for AEA on Kv1.5 channels expressed on HEK-293 cells using the patch-clamp techniques. AEA exhibited high-potency block (IC(50) approximately 200 nM) from the cytoplasmic membrane surface, consistent with open-channel block. Alanine-scanning mutagenesis revealed that AEA interacts with two crucial beta-branching amino acids, Val505 and Ile508 within the S6 domain. Both residues face toward the central cavity and constitute a motif that forms a hydrophobic ring around the ion conduction pathway. This hydrophobic ring motif may be a critical determinant of cannabinoid receptor-independent AEA modulation in other K(+) channel families.
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Affiliation(s)
- Eloy G Moreno-Galindo
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Mexico
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Li GR, Dong MQ. Pharmacology of Cardiac Potassium Channels. CARDIOVASCULAR PHARMACOLOGY - HEART AND CIRCULATION 2010; 59:93-134. [DOI: 10.1016/s1054-3589(10)59004-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Abstract
The human genome encodes 40 voltage-gated K(+) channels (K(V)), which are involved in diverse physiological processes ranging from repolarization of neuronal and cardiac action potentials, to regulating Ca(2+) signalling and cell volume, to driving cellular proliferation and migration. K(V) channels offer tremendous opportunities for the development of new drugs to treat cancer, autoimmune diseases and metabolic, neurological and cardiovascular disorders. This Review discusses pharmacological strategies for targeting K(V) channels with venom peptides, antibodies and small molecules, and highlights recent progress in the preclinical and clinical development of drugs targeting the K(V)1 subfamily, the K(V)7 subfamily (also known as KCNQ), K(V)10.1 (also known as EAG1 and KCNH1) and K(V)11.1 (also known as HERG and KCNH2) channels.
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Kozlowski D, Budrejko S, Lip GYH, Mikhailidis DP, Rysz J, Raczak G, Banach M. Vernakalant hydrochloride for the treatment of atrial fibrillation. Expert Opin Investig Drugs 2009; 18:1929-37. [DOI: 10.1517/13543780903386246] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Eldstrom J, Fedida D. Modeling of high-affinity binding of the novel atrial anti-arrhythmic agent, vernakalant, to Kv1.5 channels. J Mol Graph Model 2009; 28:226-35. [DOI: 10.1016/j.jmgm.2009.07.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Revised: 07/25/2009] [Accepted: 07/27/2009] [Indexed: 02/02/2023]
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Tamargo J, Caballero R, Gómez R, Delpón E. I(Kur)/Kv1.5 channel blockers for the treatment of atrial fibrillation. Expert Opin Investig Drugs 2009; 18:399-416. [PMID: 19335273 DOI: 10.1517/13543780902762850] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Atrial fibrillation (AF) is the most common sustained arrhythmia. Anti-arrhythmic drugs remain the mainstay of therapy, but the available class I and III anti-arrhythmic drugs are only moderately effective in long-term restoring/maintaining sinus rhythm (SR) and can produce potentially fatal ventricular pro-arrhythmia. In an attempt to identify safer and more effective anti-arrhythmic drugs, drug discovery efforts have focused on 'atrial selective drugs' that target cardiac ion channel(s) that are exclusively or predominantly expressed in the atria. The ultra-rapid activating delayed rectifier K(+) current (I(Kur)), carried by Kv1.5 channels, is a major repolarizing current in human atria, but seems to play no role in the ventricle. This finding offers the possibility of developing selective I(Kur) blockers to restore and maintain SR without a risk of ventricular pro-arrhythmia. Several I(Kur) blockers are now being developed but clinical data are still limited, so the precise role of these agents in the treatment of AF remains to be defined. In this review we analyze the possible advantages and disadvantages of the developmental I(Kur) blockers as they represent the first step for the development of potential atrial selective drugs for a more effective and safer treatment and prevention of AF.
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Affiliation(s)
- Juan Tamargo
- Universidad Complutense, School of Medicine, Department of Pharmacology, Madrid, Spain.
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A polyether biotoxin binding site on the lipid-exposed face of the pore domain of Kv channels revealed by the marine toxin gambierol. Proc Natl Acad Sci U S A 2009; 106:9896-901. [PMID: 19482941 DOI: 10.1073/pnas.0812471106] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Gambierol is a marine polycyclic ether toxin belonging to the group of ciguatera toxins. It does not activate voltage-gated sodium channels (VGSCs) but inhibits Kv1 potassium channels by an unknown mechanism. While testing whether Kv2, Kv3, and Kv4 channels also serve as targets, we found that Kv3.1 was inhibited with an IC(50) of 1.2 +/- 0.2 nM, whereas Kv2 and Kv4 channels were insensitive to 1 microM gambierol. Onset of block was similar from either side of the membrane, and gambierol did not compete with internal cavity blockers. The inhibition did not require channel opening and could not be reversed by strong depolarization. Using chimeric Kv3.1-Kv2.1 constructs, the toxin sensitivity was traced to S6, in which T427 was identified as a key determinant. In Kv3.1 homology models, T427 and other molecular determinants (L348, F351) reside in a space between S5 and S6 outside the permeation pathway. In conclusion, we propose that gambierol acts as a gating modifier that binds to the lipid-exposed surface of the pore domain, thereby stabilizing the closed state. This site may be the topological equivalent of the neurotoxin site 5 of VGSCs. Further elucidation of this previously undescribed binding site may explain why most ciguatoxins activate VGSCs, whereas others inhibit voltage-dependent potassium (Kv) channels. This previously undescribed Kv neurotoxin site may have wide implications not only for our understanding of channel function at the molecular level but for future development of drugs to alleviate ciguatera poisoning or to modulate electrical excitability in general.
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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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Yang L, Ma JH, Zhang PH, Zou AR, Tu DN. QUERCETIN ACTIVATES HUMAN Kv1.5 CHANNELS BY A RESIDUE I502 IN THE S6 SEGMENT. Clin Exp Pharmacol Physiol 2009; 36:154-61. [DOI: 10.1111/j.1440-1681.2008.05061.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Wu J, Ding WG, Matsuura H, Tsuji K, Zang WJ, Horie M. Inhibitory actions of the phosphatidylinositol 3-kinase inhibitor LY294002 on the human Kv1.5 channel. Br J Pharmacol 2009; 156:377-87. [PMID: 19154427 DOI: 10.1111/j.1476-5381.2008.00017.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND AND PURPOSE Kv1.5 channels conduct the ultra-rapid delayed rectifier potassium current (I(Kur)), and in humans, Kv1.5 channels are highly expressed in cardiac atria but are scarce in ventricles. Pharmacological blockade of human Kv1.5 (hKv1.5) has been regarded as effective for prevention and treatment of re-entry-based atrial tachyarrhythmias. Here we examined blockade of hKv1.5 channels by LY294002, a well-known inhibitor of phosphatidylinositol 3-kinase (PI3K). EXPERIMENTAL APPROACH hKv1.5 channels were heterologously expressed in Chinese hamster ovary cells. Effects of LY294002 on wild-type and mutant (T462C, H463C, T480A, R487V, A501V, I502A, I508A, L510A and V516A) hKv1.5 channels were examined by using the whole-cell patch-clamp method. KEY RESULTS LY294002 rapidly and reversibly inhibited hKv1.5 current in a concentration-dependent manner (IC(50) of 7.9 micromol.L(-1)). In contrast, wortmannin, a structurally distinct inhibitor of PI3K, had little inhibitory effect on hKv1.5 current. LY294002 block of hKv1.5 current developed with time during depolarizing voltage-clamp steps, and this blockade was also voltage-dependent with a steep increase over the voltage range for channel openings. The apparent binding (k(+1)) and unbinding (k(-1)) rate constants were calculated to be 1.6 micromol.L(-1) (-1).s(-1) and 5.7 s(-1) respectively. Inhibition by LY294002 was significantly reduced in several hKv1.5 mutant channels: T480A, R487V, I502A, I508A, L510A and V516A. CONCLUSIONS AND IMPLICATIONS LY294002 acts directly on hKv1.5 currents as an open channel blocker, independently of its effects on PI3K activity. Amino acid residues located in the pore region (Thr480, Arg487) and the S6 segment (Ile502, Ile508, Leu510, Val516) appear to constitute potential binding sites for LY294002.
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Affiliation(s)
- J Wu
- Pharmacology Department, Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, China
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Aréchiga IA, Barrio-Echavarria GF, Rodríguez-Menchaca AA, Moreno-Galindo EG, Decher N, Tristani-Firouzi M, Sánchez-Chapula JA, Navarro-Polanco RA. Kv1.5 open channel block by the antiarrhythmic drug disopyramide: molecular determinants of block. J Pharmacol Sci 2008; 108:49-55. [PMID: 18818480 DOI: 10.1254/jphs.08084fp] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Kv1.5 is considered to be a potential molecular target for treatment of atrial fibrillation or flutter. Disopyramide is widely used in the treatment of atrial flutter and/or atrial fibrillation. The present study was undertaken to characterize the effects of disopyramide on currents mediated by Kv1.5 channels and to determine the putative binding site involved in the inhibitory effects of disopyramide. Experiments were carried out on wild-type and site directed mutated hKv1.5 channels expressed on HEK 293 cells using the patch-clamp technique. Disopyramide acting from the cytoplasmic side of the membrane produced blocking effects on Kv1.5 that exhibited several features typical of an open channel blocker. Ala-scanning mutagenesis of the Kv1.5 pore domain combined with macroscopic current analysis suggested that disopyramide interacted only with the Val512 residue that faces to the central cavity of the channel. Mutation of this key residue to Ala caused marked change in the IC(50) of disopyramide (22-fold). The single interaction between disopyramide and Val512 in the PVP region is able to change the mechanism of channel closure, reproducing the "foot-in-the-door" phenomenon.
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Affiliation(s)
- Iván A Aréchiga
- Unidad de Investigación Carlos Méndez, Centro de Investigaciones Biomédicas de la Universidad de Colima, Colima, México
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Karczewski J, Kiss L, Kane SA, Koblan KS, Lynch RJ, Spencer RH. High-throughput analysis of drug binding interactions for the human cardiac channel, Kv1.5. Biochem Pharmacol 2008; 77:177-85. [PMID: 18955031 DOI: 10.1016/j.bcp.2008.09.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 09/17/2008] [Accepted: 09/25/2008] [Indexed: 10/21/2022]
Abstract
The voltage-gated potassium channel Kv1.5 is one of the key regulators of membrane potential repolarization in human atrial myocytes and is considered a potential drug target to treat atrial fibrillation. In this study we sought to determine molecular mechanism of action of DPO-1, a diphenylphosphine oxide derivative recently shown to terminate experimental atrial arrhythmia without affecting ventricular refractory period. In addition, we provided similar analysis for additional two small molecule blockers, representing different structural classes: cyclohexanones (PAC) and nor-triterpenoids (correolide). To rapidly identify the residues within the Kv1.5 channel critical for blocking activity of these molecules, two functional high-throughput ion channel assays were employed together with site-directed mutagenesis. Our study revealed that the residues critical for blocking activity of for DPO-1 include T480, localized at the outer mouth of the pore, and two residues along S6 helix: V505 and I508. The overlapping site was identified for PAC and included residues T480 and V505. In contrast to DPO-1, the I508A mutation resulted in only a modest reduction in the block of Kv1.5 by PAC (9-fold). Correolide, the largest molecule examined, made widespread interactions along the entire length of the pore (from T480 to V516). In summary, we have identified multiple residues involved in forming high affinity binding site for Kv1.5 blockers. Similar approaches of high-throughput ion channel technologies, combined with site-directed mutagenesis, may allow for parallel, rapid and accurate analysis of ion channel interactions with multiple compounds and could facilitate the design of more potent and selective ion channel blockers.
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Affiliation(s)
- Jerzy Karczewski
- Department of Pain Research, Merck Research Laboratories, West Point, PA 19486, USA.
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Mazzini MJ, Monahan KM. Pharmacotherapy for atrial arrhythmias: Present and future. Heart Rhythm 2008; 5:S26-31. [DOI: 10.1016/j.hrthm.2008.01.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Indexed: 11/29/2022]
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