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DU C, Yuan F, Duan X, Rong M, Meng E, Liu C. Isolation and structural identification of a potassium ion channel Kv4.1 inhibitor SsTx-P2 from centipede venom. Zhejiang Da Xue Xue Bao Yi Xue Ban 2024; 53:194-200. [PMID: 38268403 DOI: 10.3724/zdxbyxb-2023-0430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
OBJECTIVES To isolate a potassium ion channel Kv4.1 inhibitor from centipede venom, and to determine its sequence and structure. METHODS Ion-exchange chromatography and reversed-phase high-performance liquid chromatography were performed to separate and purify peptide components of centipede venom, and their inhibiting effect on Kv4.1 channel was determined by whole-cell patch clamp recording. The molecular weight of isolated peptide Kv4.1 channel inhibitor was identified with matrix assisted laser desorption ionization-time-of-flight mass spectrometry; its primary sequence was determined by Edman degradation sequencing and two-dimensional mass spectrometry; its structure was established based on iterative thread assembly refinement online analysis. RESULTS A peptide SsTx-P2 was separated from centipede venom with the molecular weight of 6122.8, and its primary sequence consists of 53 amino acid residues NH2-ELTWDFVRTCCKLFPDKSECTKACATEFTGGDESRLKDVWPRKLRSGDSRLKD-OH. Peptide SsTx-P2 potently inhibited the current of Kv4.1 channel transiently transfected in HEK293 cell, with 1.0 μmol/L SsTx-P2 suppressing 95% current of Kv4.1 channel. Its structure showed that SsTx-P2 shared a conserved helical structure. CONCLUSIONS The study has isolated a novel peptide SsTx-P2 from centipede venom, which can potently inhibit the potassium ion channel Kv4.1 and displays structural conservation.
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Affiliation(s)
- Canwei DU
- School of Life and Health Sciences, Hunan University of Science and Technology, Xiangtan 411201, Hunan Province, China.
| | - Fuchu Yuan
- College of Life Sciences, Hunan Normal University, Changsha 410006, China
| | - Xinyi Duan
- School of Life and Health Sciences, Hunan University of Science and Technology, Xiangtan 411201, Hunan Province, China
| | - Mingqiang Rong
- College of Life Sciences, Hunan Normal University, Changsha 410006, China
| | - Er Meng
- School of Life and Health Sciences, Hunan University of Science and Technology, Xiangtan 411201, Hunan Province, China
| | - Changjun Liu
- School of Life and Health Sciences, Hunan University of Science and Technology, Xiangtan 411201, Hunan Province, China.
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Arab I, Egghe K, Laukens K, Chen K, Barakat K, Bittremieux W. Benchmarking of Small Molecule Feature Representations for hERG, Nav1.5, and Cav1.2 Cardiotoxicity Prediction. J Chem Inf Model 2024; 64:2515-2527. [PMID: 37870574 DOI: 10.1021/acs.jcim.3c01301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
In the field of drug discovery, there is a substantial challenge in seeking out chemical structures that possess desirable pharmacological, toxicological, and pharmacokinetic properties. Complications arise when drugs interfere with the functioning of cardiac ion channels, leading to serious cardiovascular consequences. The discontinuation and removal of numerous approved drugs from the market or at late development stages in the pipeline due to such inhibitory effects further highlight the urgency of addressing this issue. Consequently, the early prediction of potential blockers targeting cardiac ion channels during the drug discovery process is of paramount importance. This study introduces a deep learning framework that computationally determines the cardiotoxicity associated with the voltage-gated potassium channel (hERG), the voltage-gated calcium channel (Cav1.2), and the voltage-gated sodium channel (Nav1.5) for drug candidates. The predictive capabilities of three feature representations─molecular fingerprints, descriptors, and graph-based numerical representations─are rigorously benchmarked. Additionally, a novel training and evaluation data set framework is presented, enabling predictive model training of drug off-target cardiotoxicity using a comprehensive and large curated data set covering these three cardiac ion channels. To facilitate these predictions, a robust and comprehensive small molecule cardiotoxicity prediction tool named CToxPred has been developed. It is made available as open source under the permissive MIT license at https://github.com/issararab/CToxPred.
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Affiliation(s)
- Issar Arab
- Department of Computer Science, University of Antwerp, 2020 Antwerp, Belgium
- Biomedical Informatics Network Antwerpen (Biomina), 2020 Antwerp, Belgium
| | - Kristof Egghe
- Department of Computer Science, University of Antwerp, 2020 Antwerp, Belgium
| | - Kris Laukens
- Department of Computer Science, University of Antwerp, 2020 Antwerp, Belgium
- Biomedical Informatics Network Antwerpen (Biomina), 2020 Antwerp, Belgium
| | - Ke Chen
- Chair for Theoretical Chemistry, Catalysis Research Center, Technische Universität München, Lichtenbergstraße 4, D-85747 Garching, Germany
| | - Khaled Barakat
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta 8613, Canada
| | - Wout Bittremieux
- Department of Computer Science, University of Antwerp, 2020 Antwerp, Belgium
- Biomedical Informatics Network Antwerpen (Biomina), 2020 Antwerp, Belgium
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3
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Szekér P, Bodó T, Klima K, Csóti Á, Hanh NN, Murányi J, Hajdara A, Szántó TG, Panyi G, Megyeri M, Péterfi Z, Farkas S, Gyöngyösi N, Hornyák P. KcsA-Kv1.x chimeras with complete ligand-binding sites provide improved predictivity for screening selective Kv1.x blockers. J Biol Chem 2024; 300:107155. [PMID: 38479597 PMCID: PMC11002876 DOI: 10.1016/j.jbc.2024.107155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/12/2024] [Accepted: 03/06/2024] [Indexed: 04/08/2024] Open
Abstract
Despite significant advances in the development of therapeutic interventions targeting autoimmune diseases and chronic inflammatory conditions, lack of effective treatment still poses a high unmet need. Modulating chronically activated T cells through the blockade of the Kv1.3 potassium channel is a promising therapeutic approach; however, developing selective Kv1.3 inhibitors is still an arduous task. Phage display-based high throughput peptide library screening is a rapid and robust approach to develop promising drug candidates; however, it requires solid-phase immobilization of target proteins with their binding site preserved. Historically, the KcsA bacterial channel chimera harboring only the turret region of the human Kv1.3 channel was used for screening campaigns. Nevertheless, literature data suggest that binding to this type of chimera does not correlate well with blocking potency on the native Kv1.3 channels. Therefore, we designed and successfully produced advanced KcsA-Kv1.3, KcsA-Kv1.1, and KcsA-Kv1.2 chimeric proteins in which both the turret and part of the filter regions of the human Kv1.x channels were transferred. These T+F (turret-filter) chimeras showed superior peptide ligand-binding predictivity compared to their T-only versions in novel phage ELISA assays. Phage ELISA binding and competition results supported with electrophysiological data confirmed that the filter region of KcsA-Kv1.x is essential for establishing adequate relative affinity order among selected peptide toxins (Vm24 toxin, Hongotoxin-1, Kaliotoxin-1, Maurotoxin, Stichodactyla toxin) and consequently obtaining more reliable selectivity data. These new findings provide a better screening tool for future drug development efforts and offer insight into the target-ligand interactions of these therapeutically relevant ion channels.
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Affiliation(s)
| | | | | | | | | | | | | | - Tibor Gábor Szántó
- Faculty of Medicine, Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, Hungary
| | - György Panyi
- Faculty of Medicine, Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, Hungary
| | | | | | | | - Norbert Gyöngyösi
- Department of Molecular Biology, Semmelweis University, Budapest, Hungary
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Zavarzina II, Kuzmenkov AI, Dobrokhotov NA, Maleeva EE, Korolkova YV, Peigneur S, Tytgat J, Krylov NA, Vassilevski AA, Chugunov AO. The scorpion toxin BeKm-1 blocks hERG cardiac potassium channels using an indispensable arginine residue. FEBS Lett 2024; 598:889-901. [PMID: 38563123 DOI: 10.1002/1873-3468.14850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/07/2024] [Accepted: 02/20/2024] [Indexed: 04/04/2024]
Abstract
BeKm-1 is a peptide toxin from scorpion venom that blocks the pore of the potassium channel hERG (Kv11.1) in the human heart. Although individual protein structures have been resolved, the structure of the complex between hERG and BeKm-1 is unknown. Here, we used molecular dynamics and ensemble docking, guided by previous double-mutant cycle analysis data, to obtain an in silico model of the hERG-BeKm-1 complex. Adding to the previous mutagenesis study of BeKm-1, our model uncovers the key role of residue Arg20, which forms three interactions (a salt bridge and hydrogen bonds) with the channel vestibule simultaneously. Replacement of this residue even by lysine weakens the interactions significantly. In accordance, the recombinantly produced BeKm-1R20K mutant exhibited dramatically decreased activity on hERG. Our model may be useful for future drug design attempts.
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Affiliation(s)
- Iana I Zavarzina
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia
| | | | - Nikita A Dobrokhotov
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia
| | | | | | | | - Jan Tytgat
- Toxicology and Pharmacology, KU Leuven, Belgium
| | - Nikolay A Krylov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
| | - Alexander A Vassilevski
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
| | - Anton O Chugunov
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
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Kuzmenkov AI, Gigolaev AM, Pinheiro-Junior EL, Peigneur S, Tytgat J, Vassilevski AA. Methionine-isoleucine dichotomy at a key position in scorpion toxins inhibiting voltage-gated potassium channels. Toxicon 2023; 231:107181. [PMID: 37301298 DOI: 10.1016/j.toxicon.2023.107181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/06/2023] [Accepted: 06/06/2023] [Indexed: 06/12/2023]
Abstract
Previous studies have identified some key amino acid residues in scorpion toxins blocking potassium channels. In particular, the most numerous toxins belonging to the α-KTx family and affecting voltage-gated potassium channels (KV) present a conserved K-C-X-N motif in the C-terminal half of their sequence. Here, we show that the X position of this motif is almost always occupied by either methionine or isoleucine. We compare the activity of three pairs of peptides that differ just by this residue on a panel of KV1 channels and find that toxins bearing methionine affect preferentially KV1.1 and 1.6 isoforms. The refined K-C-M/I-N motif stands out as the principal structural element of α-KTx conferring high affinity and selectivity to KV channels.
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Affiliation(s)
- Alexey I Kuzmenkov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
| | - Andrei M Gigolaev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | | | - Steve Peigneur
- Toxicology and Pharmacology, KU Leuven, Leuven, 3000, Belgium
| | - Jan Tytgat
- Toxicology and Pharmacology, KU Leuven, Leuven, 3000, Belgium
| | - Alexander A Vassilevski
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
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Das NR, Sharma T, Toropov AA, Toropova AP, Tripathi MK, Achary PGR. Machine-learning technique, QSAR and molecular dynamics for hERG-drug interactions. J Biomol Struct Dyn 2023; 41:13766-13791. [PMID: 37021352 DOI: 10.1080/07391102.2023.2193641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 02/06/2023] [Indexed: 04/07/2023]
Abstract
One of the most well-known anti-targets defining medication cardiotoxicity is the voltage-dependent hERG K + channel, which is well-known for its crucial involvement in cardiac action potential repolarization. Torsades de Pointes, QT prolongation, and sudden death are all caused by hERG (the human Ether-à-go-go-Related Gene) inhibition. There is great interest in creating predictive computational (in silico) tools to identify and weed out potential hERG blockers early in the drug discovery process because testing for hERG liability and the traditional experimental screening are complicated, expensive and time-consuming. This study used 2D descriptors of a large curated dataset of 6766 compounds and machine learning approaches to build robust descriptor-based QSAR and predictive classification models for KCNH2 liability. Decision Tree, Random Forest, Logistic Regression, Ada Boosting, kNN, SVM, Naïve Bayes, neural network and stochastic gradient classification classifier algorithms were used to build classification models. If a compound's IC50 value was between 10 μM and less, it was classified as a blocker (hERG-positive), and if it was more, it was classified as a non-blocker (hERG-negative). Matthew's correlation coefficient formula and F1score were applied to compare and track the developed models' performance. Molecular docking and dynamics studies were performed to understand the cardiotoxicity relating to the hERG-gene. The hERG residues interacting after 100 ns are LEU:697, THR:708, PHE:656, HIS:674, HIS:703, TRP:705 and ASN:709 and the hERG-ligand-16 complex trajectory showed stable behaviour with lesser fluctuations in the entire simulation of 200 ns.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Nilima Rani Das
- Department of CA, Siksha 'O' Anusandhan Deemed to be University, Bhubaneswar, Odisha, India
| | - Tripti Sharma
- School of Pharmaceutical Sciences, Siksha 'O' Anusandhan Deemed to be University, Bhubaneswar, Odisha, India
| | - Andrey A Toropov
- Department of Environmental Health Science, Laboratory of Environmental Chemistry and Toxicology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Alla P Toropova
- Department of Environmental Health Science, Laboratory of Environmental Chemistry and Toxicology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | | | - P Ganga Raju Achary
- Department of Chemistry, Siksha 'O' Anusandhan Deemed to be University, Bhubaneswar, Odisha, India
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7
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Feng H, Wei GW. Virtual screening of DrugBank database for hERG blockers using topological Laplacian-assisted AI models. Comput Biol Med 2023; 153:106491. [PMID: 36599209 PMCID: PMC10120853 DOI: 10.1016/j.compbiomed.2022.106491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 11/29/2022] [Accepted: 12/27/2022] [Indexed: 12/29/2022]
Abstract
The human ether-a-go-go (hERG) potassium channel (Kv11.1) plays a critical role in mediating cardiac action potential. The blockade of this ion channel can potentially lead fatal disorder and/or long QT syndrome. Many drugs have been withdrawn because of their serious hERG-cardiotoxicity. It is crucial to assess the hERG blockade activity in the early stage of drug discovery. We are particularly interested in the hERG-cardiotoxicity of compounds collected in the DrugBank database considering that many DrugBank compounds have been approved for therapeutic treatments or have high potential to become drugs. Machine learning-based in silico tools offer a rapid and economical platform to virtually screen DrugBank compounds. We design accurate and robust classifiers for blockers/non-blockers and then build regressors to quantitatively analyze the binding potency of the DrugBank compounds on the hERG channel. Molecular sequences are embedded with two natural language processing (NLP) methods, namely, autoencoder and transformer. Complementary three-dimensional (3D) molecular structures are embedded with two advanced mathematical approaches, i.e., topological Laplacians and algebraic graphs. With our state-of-the-art tools, we reveal that 227 out of the 8641 DrugBank compounds are potential hERG blockers, suggesting serious drug safety problems. Our predictions provide guidance for the further experimental interrogation of DrugBank compounds' hERG-cardiotoxicity.
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Affiliation(s)
- Hongsong Feng
- Department of Mathematics, Michigan State University, MI 48824, USA
| | - Guo-Wei Wei
- Department of Mathematics, Michigan State University, MI 48824, USA; Department of Electrical and Computer Engineering, Michigan State University, MI 48824, USA; Department of Biochemistry and Molecular Biology, Michigan State University, MI 48824, USA.
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Naseem MU, Gurrola-Briones G, Romero-Imbachi MR, Borrego J, Carcamo-Noriega E, Beltrán-Vidal J, Zamudio FZ, Shakeel K, Possani LD, Panyi G. Characterization and Chemical Synthesis of Cm39 (α-KTx 4.8): A Scorpion Toxin That Inhibits Voltage-Gated K + Channel K V1.2 and Small- and Intermediate-Conductance Ca 2+-Activated K + Channels K Ca2.2 and K Ca3.1. Toxins (Basel) 2023; 15:41. [PMID: 36668861 PMCID: PMC9866218 DOI: 10.3390/toxins15010041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/22/2022] [Accepted: 12/27/2022] [Indexed: 01/06/2023] Open
Abstract
A novel peptide, Cm39, was identified in the venom of the scorpion Centruroides margaritatus. Its primary structure was determined. It consists of 37 amino acid residues with a MW of 3980.2 Da. The full chemical synthesis and proper folding of Cm39 was obtained. Based on amino acid sequence alignment with different K+ channel inhibitor scorpion toxin (KTx) families and phylogenetic analysis, Cm39 belongs to the α-KTx 4 family and was registered with the systematic number of α-KTx 4.8. Synthetic Cm39 inhibits the voltage-gated K+ channel hKV1.2 with high affinity (Kd = 65 nM). The conductance-voltage relationship of KV1.2 was not altered in the presence of Cm39, and the analysis of the toxin binding kinetics was consistent with a bimolecular interaction between the peptide and the channel; therefore, the pore blocking mechanism is proposed for the toxin-channel interaction. Cm39 also inhibits the Ca2+-activated KCa2.2 and KCa3.1 channels, with Kd = 502 nM, and Kd = 58 nM, respectively. However, the peptide does not inhibit hKV1.1, hKV1.3, hKV1.4, hKV1.5, hKV1.6, hKV11.1, mKCa1.1 K+ channels or the hNaV1.5 and hNaV1.4 Na+ channels at 1 μM concentrations. Understanding the unusual selectivity profile of Cm39 motivates further experiments to reveal novel interactions with the vestibule of toxin-sensitive channels.
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Affiliation(s)
- Muhammad Umair Naseem
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Egyetem ter. 1, 4032 Debrecen, Hungary
| | - Georgina Gurrola-Briones
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Morelos, Mexico
| | - Margarita R. Romero-Imbachi
- Grupo de Investigaciones Herpetológicas y Toxinológicas, Centro de Investigaciones Biomédicas, Departamento de Biología, Facultad de Ciencias Naturales, Exactas y de la Educación, Universidad del Cauca, Sector Tulcan, Calle 2 N 3N-100, Popayán 190002, Cauca, Colombia
| | - Jesus Borrego
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Egyetem ter. 1, 4032 Debrecen, Hungary
| | - Edson Carcamo-Noriega
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Morelos, Mexico
| | - José Beltrán-Vidal
- Grupo de Investigaciones Herpetológicas y Toxinológicas, Centro de Investigaciones Biomédicas, Departamento de Biología, Facultad de Ciencias Naturales, Exactas y de la Educación, Universidad del Cauca, Sector Tulcan, Calle 2 N 3N-100, Popayán 190002, Cauca, Colombia
| | - Fernando Z. Zamudio
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Morelos, Mexico
| | - Kashmala Shakeel
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Egyetem ter. 1, 4032 Debrecen, Hungary
| | - Lourival Domingos Possani
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Morelos, Mexico
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Egyetem ter. 1, 4032 Debrecen, Hungary
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Maatoug S, Cheikh A, Khamessi O, Tabka H, Landoulsi Z, Guigonis JM, Diochot S, Bendahhou S, Benkhalifa R. Cross Pharmacological, Biochemical and Computational Studies of a Human Kv3.1b Inhibitor from Androctonus australis Venom. Int J Mol Sci 2021; 22:ijms222212290. [PMID: 34830172 PMCID: PMC8618407 DOI: 10.3390/ijms222212290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/05/2021] [Accepted: 11/11/2021] [Indexed: 11/23/2022] Open
Abstract
The voltage-gated K+ channels Kv3.1 display fast activation and deactivation kinetics and are known to have a crucial contribution to the fast-spiking phenotype of certain neurons. AahG50, as a natural product extracted from Androctonus australis hector venom, inhibits selectively Kv3.1 channels. In the present study, we focused on the biochemical and pharmacological characterization of the component in AahG50 scorpion venom that potently and selectively blocks the Kv3.1 channels. We used a combined optimization through advanced biochemical purification and patch-clamp screening steps to characterize the peptide in AahG50 active on Kv3.1 channels. We described the inhibitory effect of a toxin on Kv3.1 unitary current in black lipid bilayers. In silico, docking experiments are used to study the molecular details of the binding. We identified the first scorpion venom peptide inhibiting Kv3.1 current at 170 nM. This toxin is the alpha-KTx 15.1, which occludes the Kv3.1 channel pore by means of the lysine 27 lateral chain. This study highlights, for the first time, the modulation of the Kv3.1 by alpha-KTx 15.1, which could be an interesting starting compound for developing therapeutic biomolecules against Kv3.1-associated diseases.
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Affiliation(s)
- Sonia Maatoug
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
- Correspondence: (S.M.); (R.B.); Tel.: +216-98-81-27-32 (R.B.)
| | - Amani Cheikh
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
| | - Oussema Khamessi
- Laboratoire des Biomolécules Thérapeutiques, Institut Pasteur de Tunis, Université de Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia;
| | - Hager Tabka
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
- Faculté des Sciences de Bizerte, Université de Carthage, Bizerte 7021, Tunisia
| | - Zied Landoulsi
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
| | - Jean-Marie Guigonis
- Laboratory Transporter in Imaging and Radiotherapy in Oncology (TIRO), Direction de la Recherche Fondamentale (DRF), Institut des Sciences du Vivant Fréderic Joliot, Commissariat à l′Energie Atomique et aux Énergies Alternatives (CEA), Université Côte d’Azur, F-06107 Nice, France;
| | - Sylvie Diochot
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Valbonne, France;
| | - Saïd Bendahhou
- UMR7370 CNRS, LP2M, Université Côte d’Azur, Labex ICST, Nice, France;
| | - Rym Benkhalifa
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
- Correspondence: (S.M.); (R.B.); Tel.: +216-98-81-27-32 (R.B.)
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Alghanmi RM, Basha MT, Soliman SM, Alsaeedi RK. New Charge Transfer Complexes of K +-Channel-Blocker Drug (Amifampridine; AMFP) for Sensitive Detection; Solution Investigations and DFT Studies. Molecules 2021; 26:molecules26196037. [PMID: 34641581 PMCID: PMC8512129 DOI: 10.3390/molecules26196037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/26/2021] [Accepted: 09/28/2021] [Indexed: 11/16/2022] Open
Abstract
UV-Vis spectroscopy was used to investigate two new charge transfer (CT) complexes formed between the K+-channel-blocker amifampridine (AMFP) drug and the two π-acceptors 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and tetracyanoethylene (TCNE) in different solvents. The molecular composition of the new CT complexes was estimated using the continuous variations method and found to be 1:1 for both complexes. The formed CT complexes' electronic spectra data were further employed for calculating the formation constants (KCT), molar extinction coefficients (εCT), and physical parameters at various temperatures, and the results demonstrated the high stability of both complexes. In addition, sensitive spectrophotometric methods for quantifying AMFP in its pure form were proposed and statistically validated. Furthermore, DFT calculations were used to predict the molecular structures of AMFP-DDQ and AMFP-TCNE complexes in CHCl3. TD-DFT calculations were also used to predict the electronic spectra of both complexes. A CT-based transition band (exp. 399 and 417 nm) for the AMFP-TCNE complex was calculated at 411.5 nm (f = 0.105, HOMO-1 → LUMO). The two absorption bands at 459 nm (calc. 426.9 nm, f = 0.054) and 584 nm (calc. 628.1 nm, f = 0.111) of the AMFP-DDQ complex were theoretically assigned to HOMO-1 → LUMO and HOMO → LUMO excitations, respectively.
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Affiliation(s)
- Reem M. Alghanmi
- Department of Chemistry, College of Science, University of Jeddah, P.O. 80327, Jeddah 21589, Saudi Arabia; (M.T.B.); (R.K.A.)
- Correspondence:
| | - Maram T. Basha
- Department of Chemistry, College of Science, University of Jeddah, P.O. 80327, Jeddah 21589, Saudi Arabia; (M.T.B.); (R.K.A.)
| | - Saied M. Soliman
- Department of Chemistry, Faculty of Science, Alexandria University, P.O. 426, Ibrahimia, Alexandria 21525, Egypt;
| | - Razan K. Alsaeedi
- Department of Chemistry, College of Science, University of Jeddah, P.O. 80327, Jeddah 21589, Saudi Arabia; (M.T.B.); (R.K.A.)
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11
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Ramírez D, Mejia-Gutierrez M, Insuasty B, Rinné S, Kiper AK, Platzk M, Müller T, Decher N, Quiroga J, De-la-Torre P, González W. 5-(Indol-2-yl)pyrazolo[3,4- b]pyridines as a New Family of TASK-3 Channel Blockers: A Pharmacophore-Based Regioselective Synthesis. Molecules 2021; 26:molecules26133897. [PMID: 34202296 PMCID: PMC8271858 DOI: 10.3390/molecules26133897] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/16/2021] [Accepted: 06/18/2021] [Indexed: 11/16/2022] Open
Abstract
TASK channels belong to the two-pore-domain potassium (K2P) channels subfamily. These channels modulate cellular excitability, input resistance, and response to synaptic stimulation. TASK-channel inhibition led to membrane depolarization. TASK-3 is expressed in different cancer cell types and neurons. Thus, the discovery of novel TASK-3 inhibitors makes these bioactive compounds very appealing to explore new cancer and neurological therapies. TASK-3 channel blockers are very limited to date, and only a few heterofused compounds have been reported in the literature. In this article, we combined a pharmacophore hypothesis with molecular docking to address for the first time the rational design, synthesis, and evaluation of 5-(indol-2-yl)pyrazolo[3,4-b]pyridines as a novel family of human TASK-3 channel blockers. Representative compounds of the synthesized library were assessed against TASK-3 using Fluorometric imaging plate reader-Membrane Potential assay (FMP). Inhibitory properties were validated using two-electrode voltage-clamp (TEVC) methods. We identified one active hit compound (MM-3b) with our systematic pipeline, exhibiting an IC50 ≈ 30 μM. Molecular docking models suggest that compound MM-3b binds to TASK-3 at the bottom of the selectivity filter in the central cavity, similar to other described TASK-3 blockers such as A1899 and PK-THPP. Our in silico and experimental studies provide a new tool to predict and design novel TASK-3 channel blockers.
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Affiliation(s)
- David Ramírez
- Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Llano Subercaseaux 2801-Piso 5, Santiago 8900000, Chile
- Correspondence: (D.R.); (P.D.-l.-T.); (W.G.)
| | - Melissa Mejia-Gutierrez
- Heterocyclic Compounds Research Group, Department of Chemistry, Universidad del Valle, A.A, Cali 760031, Colombia; (M.M.-G.); (B.I.); (J.Q.)
| | - Braulio Insuasty
- Heterocyclic Compounds Research Group, Department of Chemistry, Universidad del Valle, A.A, Cali 760031, Colombia; (M.M.-G.); (B.I.); (J.Q.)
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Center for Mind, Brain and Behavior (CMBB), Philipps-University of Marburg, Deutschhausstraße 2, 35037 Marburg, Germany; (S.R.); (A.K.K.); (N.D.)
| | - Aytug K. Kiper
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Center for Mind, Brain and Behavior (CMBB), Philipps-University of Marburg, Deutschhausstraße 2, 35037 Marburg, Germany; (S.R.); (A.K.K.); (N.D.)
| | - Magdalena Platzk
- Joint Pulmonary Drug Discovery Lab Bayer-MGH, Boston, MA 02114, USA;
| | - Thomas Müller
- Bayer AG, Research & Development, Pharmaceuticals, D-42096 Wuppertal, Germany;
| | - Niels Decher
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Center for Mind, Brain and Behavior (CMBB), Philipps-University of Marburg, Deutschhausstraße 2, 35037 Marburg, Germany; (S.R.); (A.K.K.); (N.D.)
| | - Jairo Quiroga
- Heterocyclic Compounds Research Group, Department of Chemistry, Universidad del Valle, A.A, Cali 760031, Colombia; (M.M.-G.); (B.I.); (J.Q.)
| | - Pedro De-la-Torre
- Department of Otolaryngology, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA 02114, USA
- Caribe Therapeutics, Vía 40 No. 69-111, Oficina 804 A, Barranquilla 080002, Colombia
- Correspondence: (D.R.); (P.D.-l.-T.); (W.G.)
| | - Wendy González
- Centro de Bioinformática, Simulación y Modelado (CBSM), Facultad de Ingeniería, Universidad de Talca, Poniente No. 1141, Talca 3460000, Chile
- Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Universidad de Talca, Talca 3460000, Chile
- Correspondence: (D.R.); (P.D.-l.-T.); (W.G.)
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12
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DeMarco KR, Yang PC, Singh V, Furutani K, Dawson JRD, Jeng MT, Fettinger JC, Bekker S, Ngo VA, Noskov SY, Yarov-Yarovoy V, Sack JT, Wulff H, Clancy CE, Vorobyov I. Molecular determinants of pro-arrhythmia proclivity of d- and l-sotalol via a multi-scale modeling pipeline. J Mol Cell Cardiol 2021; 158:163-177. [PMID: 34062207 PMCID: PMC8906354 DOI: 10.1016/j.yjmcc.2021.05.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 05/03/2021] [Accepted: 05/24/2021] [Indexed: 11/20/2022]
Abstract
Drug isomers may differ in their proarrhythmia risk. An interesting example is the drug sotalol, an antiarrhythmic drug comprising d- and l- enantiomers that both block the hERG cardiac potassium channel and confer differing degrees of proarrhythmic risk. We developed a multi-scale in silico pipeline focusing on hERG channel – drug interactions and used it to probe and predict the mechanisms of pro-arrhythmia risks of the two enantiomers of sotalol. Molecular dynamics (MD) simulations predicted comparable hERG channel binding affinities for d- and l-sotalol, which were validated with electrophysiology experiments. MD derived thermodynamic and kinetic parameters were used to build multi-scale functional computational models of cardiac electrophysiology at the cell and tissue scales. Functional models were used to predict inactivated state binding affinities to recapitulate electrocardiogram (ECG) QT interval prolongation observed in clinical data. Our study demonstrates how modeling and simulation can be applied to predict drug effects from the atom to the rhythm for dl-sotalol and also increased proarrhythmia proclivity of d- vs. l-sotalol when accounting for stereospecific beta-adrenergic receptor blocking.
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Affiliation(s)
- Kevin R DeMarco
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA
| | - Pei-Chi Yang
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA
| | - Vikrant Singh
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Kazuharu Furutani
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA; Department of Pharmacology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Tokushima 770-8514, Japan
| | - John R D Dawson
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA; Biophysics Graduate Group, University of California Davis, Davis, CA 95616, USA
| | - Mao-Tsuen Jeng
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA
| | - James C Fettinger
- Department of Chemistry, University of California Davis, Davis, CA 95616, USA
| | - Slava Bekker
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA; Department of Science and Engineering, American River College, Sacramento, CA 95841, USA
| | - Van A Ngo
- Centre for Molecular Simulation and Biochemistry Research Cluster, Department of Biological Sciences, University of Calgary, Calgary, AB T2N1N4, Canada
| | - Sergei Y Noskov
- Centre for Molecular Simulation and Biochemistry Research Cluster, Department of Biological Sciences, University of Calgary, Calgary, AB T2N1N4, Canada
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA; Department of Anesthesiology and Pain Medicine, University of California Davis, Davis, CA 95616, USA
| | - Jon T Sack
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA; Department of Anesthesiology and Pain Medicine, University of California Davis, Davis, CA 95616, USA
| | - Heike Wulff
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Colleen E Clancy
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA; Department of Pharmacology, University of California Davis, Davis, CA 95616, USA
| | - Igor Vorobyov
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA; Department of Pharmacology, University of California Davis, Davis, CA 95616, USA.
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13
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Zhang HH, Zhang XK, Si RR, Shen SC, Liang TT, Fan TT, Chen W, Xu LH, Han BN. Chemical and Biological Study of Novel Aplysiatoxin Derivatives from the Marine Cyanobacterium Lyngbya sp. Toxins (Basel) 2020; 12:E733. [PMID: 33238397 PMCID: PMC7700248 DOI: 10.3390/toxins12110733] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/05/2020] [Accepted: 11/20/2020] [Indexed: 12/03/2022] Open
Abstract
Since 1970s, aplysiatoxins (ATXs), a class of biologically active dermatoxins, were identified from the marine mollusk Stylocheilus longicauda, whilst further research indicated that ATXs were originally metabolized by cyanobacteria. So far, there have been 45 aplysiatoxin derivatives discovered from marine cyanobacteria with various geographies. Recently, we isolated two neo-debromoaplysiatoxins, neo-debromoaplysiatoxin G (1) and neo-debromoaplysiatoxin H (2) from the cyanobacterium Lyngbya sp. collected from the South China Sea. The freeze-dried cyanobacterium was extracted with liquid-liquid extraction of organic solvents, and then was subjected to multiple chromatographies to yield neo-debromoaplysiatoxin G (1) (3.6 mg) and neo-debromoaplysiatoxin H (2) (4.3 mg). They were elucidated with spectroscopic methods. Moreover, the brine shrimp toxicity of the aplysiatoxin derivatives representing differential structural classifications indicated that the debromoaplysiatoxin was the most toxic compound (half inhibitory concentration (IC50) value = 0.34 ± 0.036 µM). While neo-aplysiatoxins (neo-ATXs) did not exhibit apparent brine shrimp toxicity, but showed potent blocking action against potassium channel Kv1.5, likewise, compounds 1 and 2 with IC50 values of 1.79 ± 0.22 µM and 1.46 ± 0.14 µM, respectively. Therefore, much of the current knowledge suggests the ATXs with different structure modifications may modulate multiple cellular signaling processes in animal systems leading to the harmful effects on public health.
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Affiliation(s)
- Hui-Hui Zhang
- Department of Development Technology of Marine Resources, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; (H.-H.Z.); (X.-K.Z.); (S.-C.S.); (T.-T.F.); (W.C.)
| | - Xin-Kai Zhang
- Department of Development Technology of Marine Resources, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; (H.-H.Z.); (X.-K.Z.); (S.-C.S.); (T.-T.F.); (W.C.)
| | - Ran-Ran Si
- School of Materials Science and Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China;
| | - Si-Cheng Shen
- Department of Development Technology of Marine Resources, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; (H.-H.Z.); (X.-K.Z.); (S.-C.S.); (T.-T.F.); (W.C.)
| | - Ting-Ting Liang
- School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 201418, China;
| | - Ting-Ting Fan
- Department of Development Technology of Marine Resources, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; (H.-H.Z.); (X.-K.Z.); (S.-C.S.); (T.-T.F.); (W.C.)
| | - Wei Chen
- Department of Development Technology of Marine Resources, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; (H.-H.Z.); (X.-K.Z.); (S.-C.S.); (T.-T.F.); (W.C.)
| | - Lian-Hua Xu
- Department of Development Technology of Marine Resources, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; (H.-H.Z.); (X.-K.Z.); (S.-C.S.); (T.-T.F.); (W.C.)
| | - Bing-Nan Han
- Department of Development Technology of Marine Resources, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; (H.-H.Z.); (X.-K.Z.); (S.-C.S.); (T.-T.F.); (W.C.)
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14
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Xie Z, Zhao Y, Yang W, Li W, Wu Y, Chen Z. Methotrexate, a small molecular scaffold targeting Kv1.3 channel extracellular pore region. Biochem Biophys Res Commun 2020; 532:265-270. [PMID: 32863001 DOI: 10.1016/j.bbrc.2020.08.050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/14/2020] [Accepted: 08/18/2020] [Indexed: 11/18/2022]
Abstract
Methotrexate (MTX) has been widely used for the treatment of many types of autoimmune diseases, such as rheumatoid arthritis, psoriasis and dermatomyositis. However, its pharmacological mechanism is still unclear completely. In this study, we found that MTX is a potent and selective inhibitor of the Kv1.3 channel, a class of potassium channels highly associated with autoimmune diseases. Electrophysiological experiments showed that MTX inhibited human Kv1.3 channel with an IC50 of 41.5 ± 24.9 nM, and 1 μM MTX inhibited 32.6 ± 1.3% and 25.6 ± 2.2% of human Kv1.1 and Kv1.2 channel currents, respectively. These data implied the unique selectivity of MTX towards the Kv1.3 channel. Excitingly, using channel activation and chimeric experiments, we found that MTX bound to the outer pore region of Kv1.3 channel. Mutagenesis experiments in the Kv.3 channel extracellular pore region further showed that the Dsp371, Thr373 and His399 residues of outer pore region of Kv1.3 channel played important roles in MTX inhibiting activities. In conclusion, MTX inhibited Kv1.3 channel by targeting extracellular pore region, which is different form all the report small molecules, such as PAP-1 and 4-AP, but similar with many natural animal toxin peptides, such as ChTX, ShK and BmKTX. To the best of our knowledge, MTX is the first small molecular scaffold targeting the Kv1.3 channel extracellular pore region, suggesting its potential applications for designing novel Kv1.3 lead drugs and treating Kv1.3 channel-associated autoimmune diseases.
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Affiliation(s)
- Zili Xie
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Yonghui Zhao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Weishan Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China; Biodrug Research Center, Wuhan University, Wuhan, 430072, China
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China; Biodrug Research Center, Wuhan University, Wuhan, 430072, China.
| | - Zongyun Chen
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan, 442000, China; State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China; Biodrug Research Center, Wuhan University, Wuhan, 430072, China.
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15
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Wan H, Selvaggio G, Pearlstein RA. Toward in vivo-relevant hERG safety assessment and mitigation strategies based on relationships between non-equilibrium blocker binding, three-dimensional channel-blocker interactions, dynamic occupancy, dynamic exposure, and cellular arrhythmia. PLoS One 2020; 15:e0234946. [PMID: 33147278 PMCID: PMC7641409 DOI: 10.1371/journal.pone.0234946] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/16/2020] [Indexed: 12/26/2022] Open
Abstract
The human ether-a-go-go-related voltage-gated cardiac ion channel (commonly known as hERG) conducts the rapid outward repolarizing potassium current in cardiomyocytes (IKr). Inadvertent blockade of this channel by drug-like molecules represents a key challenge in pharmaceutical R&D due to frequent overlap between the structure-activity relationships of hERG and many primary targets. Building on our previous work, together with recent cryo-EM structures of hERG, we set about to better understand the energetic and structural basis of promiscuous blocker-hERG binding in the context of Biodynamics theory. We propose a two-step blocker binding process consisting of: The initial capture step: diffusion of a single fully solvated blocker copy into a large cavity lined by the intra-cellular cyclic nucleotide binding homology domain (CNBHD). Occupation of this cavity is a necessary but insufficient condition for ion current disruption.The IKr disruption step: translocation of the captured blocker along the channel axis, such that: The head group, consisting of a quasi-rod-shaped moiety, projects into the open pore, accompanied by partial de-solvation of the binding interface.One tail moiety packs along a kink between the S6 helix and proximal C-linker helix adjacent to the intra-cellular entrance of the pore, likewise accompanied by mutual de-solvation of the binding interface (noting that the association barrier is comprised largely of the total head + tail group de-solvation cost).Blockers containing a highly planar moiety that projects into a putative constriction zone within the closed channel become trapped upon closing, as do blockers terminating prior to this region.A single captured blocker copy may conceivably associate and dissociate to/from the pore many times before exiting the CNBHD cavity. Lastly, we highlight possible flaws in the current hERG safety index (SI), and propose an alternate in vivo-relevant strategy factoring in: Benefit/risk.The predicted arrhythmogenic fractional hERG occupancy (based on action potential (AP) simulations of the undiseased human ventricular cardiomyocyte).Alteration of the safety threshold due to underlying disease.Risk of exposure escalation toward the predicted arrhythmic limit due to patient-to-patient pharmacokinetic (PK) variability, drug-drug interactions, overdose, and use for off-label indications in which the hERG safety parameters may differ from their on-label counterparts.
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Affiliation(s)
- Hongbin Wan
- Global Discovery Chemistry, Computer-Aided Drug Discovery, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, United States of America
| | - Gianluca Selvaggio
- Global Discovery Chemistry, Computer-Aided Drug Discovery, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, United States of America
| | - Robert A. Pearlstein
- Global Discovery Chemistry, Computer-Aided Drug Discovery, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, United States of America
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Gopalsamy B, Chia JSM, Farouk AAO, Sulaiman MR, Perimal EK. Zerumbone-Induced Analgesia Modulated via Potassium Channels and Opioid Receptors in Chronic Constriction Injury-Induced Neuropathic Pain. Molecules 2020; 25:molecules25173880. [PMID: 32858809 PMCID: PMC7503342 DOI: 10.3390/molecules25173880] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/29/2020] [Accepted: 08/03/2020] [Indexed: 12/15/2022] Open
Abstract
Zerumbone, a monocyclic sesquiterpene from the wild ginger plant Zingiber zerumbet (L.) Smith, attenuates allodynia and hyperalgesia. Currently, its mechanisms of action in neuropathic pain conditions remain unclear. This study examines the involvement of potassium channels and opioid receptors in zerumbone-induced analgesia in a chronic constriction injury (CCI) neuropathic pain mice model. Male Institute of Cancer Research (ICR) mice were subjected to CCI and behavioral responses were tested on day 14. Responses toward mechanical allodynia and thermal hyperalgesia were tested with von Frey's filament and Hargreaves' tests, respectively. Symptoms of neuropathic pain were significantly alleviated following treatment with zerumbone (10 mg/kg; intraperitoneal, i.p.). However, when the voltage-dependent K+ channel blocker tetraethylammonium (TEA, 4 mg/kg; i.p.), ATP-sensitive K+ channel blocker, glibenclamide (GLIB, 10 mg/kg; i.p.); small-conductance Ca2+-activated K+ channel inhibitor apamin (APA, 0.04 mg/kg; i.p.), or large-conductance Ca2+-activated K+ channel inhibitor charybdotoxin (CHAR, 0.02 mg/kg; i.p.) was administered prior to zerumbone (10 mg/kg; i.p.), the antiallodynic and antihyperalgesic effects of zerumbone were significantly reversed. Additionally, non-specific opioid receptors antagonist, naloxone (NAL, 10 mg/kg; i.p.), selective µ-, δ- and κ-opioid receptor antagonists; β-funaltrexamine (β-FN, 40 mg/kg; i.p.), naltrindole (20 mg/kg; s.c.), nor-binaltorphamine (10 mg/kg; s.c.) respectively attenuated the antiallodynic and antihyperalgesic effects of zerumbone. This outcome clearly demonstrates the participation of potassium channels and opioid receptors in the antineuropathic properties of zerumbone. As various clinically used neuropathic pain drugs also share this similar mechanism, this compound is, therefore, a highly potential substitute to these therapeutic options.
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Affiliation(s)
- Banulata Gopalsamy
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (B.G.); (A.A.O.F.); (M.R.S.)
| | - Jasmine Siew Min Chia
- Centre for Community Health Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia;
| | - Ahmad Akira Omar Farouk
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (B.G.); (A.A.O.F.); (M.R.S.)
| | - Mohd Roslan Sulaiman
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (B.G.); (A.A.O.F.); (M.R.S.)
| | - Enoch Kumar Perimal
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (B.G.); (A.A.O.F.); (M.R.S.)
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, University of Adelaide, Adelaide 5000, Australia
- Correspondence: ; Tel./Fax: +61-603-8947-2774
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17
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Choi KE, Balupuri A, Kang NS. The Study on the hERG Blocker Prediction Using Chemical Fingerprint Analysis. Molecules 2020; 25:E2615. [PMID: 32512802 PMCID: PMC7321128 DOI: 10.3390/molecules25112615] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/01/2020] [Accepted: 06/02/2020] [Indexed: 01/31/2023] Open
Abstract
Human ether-a-go-go-related gene (hERG) potassium channel blockage by small molecules may cause severe cardiac side effects. Thus, it is crucial to screen compounds for activity on the hERG channels early in the drug discovery process. In this study, we collected 5299 hERG inhibitors with diverse chemical structures from a number of sources. Based on this dataset, we evaluated different machine learning (ML) and deep learning (DL) algorithms using various integer and binary type fingerprints. A training set of 3991 compounds was used to develop quantitative structure-activity relationship (QSAR) models. The performance of the developed models was evaluated using a test set of 998 compounds. Models were further validated using external set 1 (263 compounds) and external set 2 (47 compounds). Overall, models with integer type fingerprints showed better performance than models with no fingerprints, converted binary type fingerprints or original binary type fingerprints. Comparison of ML and DL algorithms revealed that integer type fingerprints are suitable for ML, whereas binary type fingerprints are suitable for DL. The outcomes of this study indicate that the rational selection of fingerprints is important for hERG blocker prediction.
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Affiliation(s)
| | | | - Nam Sook Kang
- Graduate School of New Drug Discovery and Development, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea; (K.-E.C.); (A.B.)
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18
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Al-Sabi A, Daly D, Rooney M, Hughes C, Kinsella GK, Kaza SK, Nolan K, Oliver Dolly J. Development of a selective inhibitor for Kv1.1 channels prevalent in demyelinated nerves. Bioorg Chem 2020; 100:103918. [PMID: 32428746 DOI: 10.1016/j.bioorg.2020.103918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 03/23/2020] [Accepted: 05/05/2020] [Indexed: 11/19/2022]
Abstract
Members of the voltage-gated K+ channel subfamily (Kv1), involved in regulating transmission between neurons or to muscles, are associated with human diseases and, thus, putative targets for neurotherapeutics. This applies especially to those containing Kv1.1 α subunits which become prevalent in murine demyelinated axons and appear abnormally at inter-nodes, underlying the perturbed propagation of nerve signals. To overcome this dysfunction, akin to the consequential debilitation in multiple sclerosis (MS), small inhibitors were sought that are selective for the culpable hyper-polarising K+ currents. Herein, we report a new semi-podand - compound 3 - that was designed based on the modelling of its interactions with the extracellular pore region in a deduced Kv1.1 channel structure. After synthesis, purification, and structural characterisation, compound 3 was found to potently (IC50 = 8 µM) and selectively block Kv1.1 and 1.6 channels. The tested compound showed no apparent effect on native Nav and Cav channels expressed in F-11 cells. Compound 3 also extensively and selectively inhibited MS-related Kv1.1 homomer but not the brain native Kv1.1- or 1.6-containing channels. These collective findings highlight the therapeutic potential of compound 3 to block currents mediated by Kv1.1 channels enriched in demyelinated central neurons.
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Affiliation(s)
- Ahmed Al-Sabi
- College of Engineering and Technology, American University of the Middle East, Kuwait; International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland
| | - Declan Daly
- School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland
| | - Myles Rooney
- School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland
| | - Cian Hughes
- School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland
| | - Gemma K Kinsella
- School of Food Science and Environmental Health, College of Sciences and Health, Technological University Dublin, Cathal Brugha Street, Dublin 1, Ireland
| | - Seshu K Kaza
- International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland
| | - Kieran Nolan
- School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland.
| | - J Oliver Dolly
- International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland
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19
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Zhao R, Dai H, Mendelman N, Chill JH, Goldstein SAN. Tethered peptide neurotoxins display two blocking mechanisms in the K + channel pore as do their untethered analogs. Sci Adv 2020; 6:eaaz3439. [PMID: 32181366 PMCID: PMC7056315 DOI: 10.1126/sciadv.aaz3439] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 12/10/2019] [Indexed: 06/10/2023]
Abstract
We show here that membrane-tethered toxins facilitate the biophysical study of the roles of toxin residues in K+ channel blockade to reveal two blocking mechanisms in the K+ channel pore. The structure of the sea anemone type I (SAK1) toxin HmK is determined by NMR. T-HmK residues are scanned by point mutation to map the toxin surface, and seven residues are identified to be critical to occlusion of the KcsA channel pore. T-HmK-Lys22 is shown to interact with K+ ions traversing the KcsA pore from the cytoplasm conferring voltage dependence on the toxin off rate, a classic mechanism that we observe as well with HmK in solution and for Kv1.3 channels. In contrast, two related SAK1 toxins, Hui1 and ShK, block KcsA and Kv1.3, respectively, via an arginine rather than the canonical lysine, when tethered and as free peptides.
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Affiliation(s)
- Ruiming Zhao
- Departments of Pediatrics and Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
| | - Hui Dai
- Departments of Pediatrics and Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
| | - Netanel Mendelman
- Department of Chemistry, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Jordan H. Chill
- Department of Chemistry, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Steve A. N. Goldstein
- Departments of Pediatrics and Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
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20
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Vazquez-Cintron E, Machamer J, Ondeck C, Pagarigan K, Winner B, Bodner P, Kelly K, Pennington MR, McNutt P. Symptomatic treatment of botulism with a clinically approved small molecule. JCI Insight 2020; 5:132891. [PMID: 31996484 DOI: 10.1172/jci.insight.132891] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 12/18/2019] [Indexed: 11/17/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are potent neuroparalytic toxins that cause mortality through respiratory paralysis. The approved medical countermeasure for BoNT poisoning is infusion of antitoxin immunoglobulins. However, antitoxins have poor therapeutic efficacy in symptomatic patients; thus, there is an urgent need for treatments that reduce the need for artificial ventilation. We report that the US Food and Drug Administration-approved potassium channel blocker 3,4-diaminopyridine (3,4-DAP) reverses respiratory depression and neuromuscular weakness in murine models of acute and chronic botulism. In ex vivo studies, 3,4-DAP restored end-plate potentials and twitch contractions of diaphragms isolated from mice at terminal stages of BoNT serotype A (BoNT/A) botulism. In vivo, human-equivalent doses of 3,4-DAP reversed signs of severe respiratory depression and restored mobility in BoNT/A-intoxicated mice at terminal stages of respiratory collapse. Multiple-dosing administration of 3,4-DAP improved respiration and extended survival at up to 5 LD50 BoNT/A. Finally, 3,4-DAP reduced gastrocnemius muscle paralysis and reversed respiratory depression in sublethal models of serotype A-, B-, and E-induced botulism. These findings make a compelling argument for repurposing 3,4-DAP to symptomatically treat symptoms of muscle paralysis caused by botulism, independent of serotype. Furthermore, they suggest that 3,4-DAP is effective for a range of botulism symptoms at clinically relevant time points.
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21
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Chen L, Yang J, Li X, Liang T, Nie C, Xie F, Liu K, Peng X, Xie J. Carbon nanoparticles enhance potassium uptake via upregulating potassium channel expression and imitating biological ion channels in BY-2 cells. J Nanobiotechnology 2020; 18:21. [PMID: 31992314 PMCID: PMC6986061 DOI: 10.1186/s12951-020-0581-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 01/16/2020] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Carbon nanoparticles (CNPs) have been reported to boost plant growth, while the mechanism that CNPs enhanced potassium uptake for plant growth has not been reported so far. RESULTS In this study, the function that CNPs promoted potassium uptake in BY-2 cells was established and the potassium accumulated in cells had a significant correlation with the fresh biomass of BY-2 cells. The K+ accumulation in cells increased with the increasing concentration of CNPs. The K+ influx reached high level after treatment with CNPs and was significantly higher than that of the control group and the negative group treated with K+ channels blocker, tetraethylammonium chloride (TEA+). The K+ accumulation was not reduced in the presence of CNPs inhibitors. In the presence of potassium channel blocker TEA+ or CNPs inhibitors, the NKT1 gene expression was changed compared with the control group. The CNPs were found to preferentially transport K+ than other cations determined by rectification of ion current assay (RIC) in a conical nanocapillary. CONCLUSIONS These results indicated that CNPs upregulated potassium gene expression to enhance K+ accumulation in BY-2 cells. Moreover, it was speculated that the CNPs simulated protein of ion channels via bulk of carboxyl for K+ permeating. These findings will provide support for improving plant growth by carbon nanoparticles.
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Affiliation(s)
- Lijuan Chen
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, 116024, China
| | - Jinchu Yang
- Technology Center, China Tobacco Henan Industrial Co. Ltd, Zhengzhou, 450000, China
| | - Xiang Li
- Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou, 450001, China
| | - Taibo Liang
- Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou, 450001, China
| | - Cong Nie
- Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou, 450001, China
| | - Fuwei Xie
- Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou, 450001, China
| | - Kejian Liu
- Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou, 450001, China
| | - Xiaojun Peng
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, 116024, China
| | - Jianping Xie
- Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou, 450001, China.
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22
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Zangerl-Plessl EM, Berger M, Drescher M, Chen Y, Wu W, Maulide N, Sanguinetti M, Stary-Weinzinger A. Toward a Structural View of hERG Activation by the Small-Molecule Activator ICA-105574. J Chem Inf Model 2020; 60:360-371. [PMID: 31877041 DOI: 10.1021/acs.jcim.9b00737] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Outward current conducted by human ether-à-go-go-related gene type 1 (hERG1) K+ channels is important for action potential repolarization in the human ventricle. Rapid, voltage-dependent inactivation greatly reduces outward currents conducted by hERG1 channels and involves conformational changes in the ion selectivity filter (SF). Recently, compounds have been found that activate hERG1 channel function by modulating gating mechanisms such as reducing inactivation. Such activating compounds could represent a novel approach to prevent arrhythmias associated with prolonged ventricular repolarization associated with inherited or acquired long QT syndrome. ICA-105574 (ICA), a 3-nitro-n-(4-phenoxyphenyl) benzamide derivative activates hERG1 by strongly attenuating pore-type inactivation. We previously mapped the putative binding site for ICA to a hydrophobic pocket located between two adjacent subunits. Here, we used the recently reported cryoelectron microscopy structures of hERG1 to elucidate the structural mechanisms by which ICA influences the stability of the SF. By combining molecular dynamics simulations, voltage-clamp electrophysiology, and the synthesis of novel ICA derivatives, we provide atomistic insights into SF dynamics and propose a structural link between the SF and S6 segments. Further, our study highlights the importance of the nitro moiety, at the meta position of the benzamide ring, for the activity of ICA and reveals that the (bio)isosteric substitution of this side chain can switch the activity to weak inhibitors. Our findings indicate that ICA increases the stability of the SF to attenuate channel inactivation, and this action requires a fine-tuned compound geometry.
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Affiliation(s)
- Eva-Maria Zangerl-Plessl
- Department of Pharmacology and Toxicology , University of Vienna , Althanstrasse 14 , Wien , Vienna 1090 , Austria
| | - Martin Berger
- Institute of Organic Chemistry , University of Vienna , Währinger Strasse 38 , Wien , Vienna 1090 , Austria
| | - Martina Drescher
- Institute of Organic Chemistry , University of Vienna , Währinger Strasse 38 , Wien , Vienna 1090 , Austria
| | - Yong Chen
- Institute of Organic Chemistry , University of Vienna , Währinger Strasse 38 , Wien , Vienna 1090 , Austria
| | - Wei Wu
- Nora Eccles Harrison Cardiovascular Research and Training Institute and Division of Cardiovascular Medicine, Department of Internal Medicine , University of Utah , Salt Lake City , Utah 84132-340 , United States
| | - Nuno Maulide
- Institute of Organic Chemistry , University of Vienna , Währinger Strasse 38 , Wien , Vienna 1090 , Austria
| | - Michael Sanguinetti
- Nora Eccles Harrison Cardiovascular Research and Training Institute and Division of Cardiovascular Medicine, Department of Internal Medicine , University of Utah , Salt Lake City , Utah 84132-340 , United States
| | - Anna Stary-Weinzinger
- Department of Pharmacology and Toxicology , University of Vienna , Althanstrasse 14 , Wien , Vienna 1090 , Austria
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23
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Li S, Sunchen S, He D, Qin C, Zuo Z, Shen B, Cao Z, Hong W, Miao L. ImKTx96, a peptide blocker of the Kv1.2 ion channel from the venom of the scorpion Isometrus maculates. Peptides 2020; 123:170172. [PMID: 31626826 DOI: 10.1016/j.peptides.2019.170172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 10/03/2019] [Accepted: 10/04/2019] [Indexed: 01/13/2023]
Abstract
Scorpion venom contains diverse bioactive peptides that can recognize and interact with membrane proteins such as ion channels. These natural toxins are believed to be useful tools for exploring the structure and function of ion channels. In this study, we characterized a K+-channel toxin gene, ImKTx96, from the venom gland cDNA library of the scorpion Isometrus maculates. The peptide deduced from the ImKTx96 precursor nucleotide sequence contains a signal peptide of 27 amino acid residues and a mature peptide of 29 residues with three disulfide bridges. Multiple sequence alignment indicated that ImKTx96 is similar with the scorpion toxins that typically target K+-channels. The recombined ImKTx96 peptide (rImKTx96) was expressed in the Escherichia coli system, and purified by GST-affinity chromatography and RP-HPLC. Results from whole-cell patch-clamp experiments revealed that rImKTx96 can inhibit the current of the Kv1.2 ion channel expressed in HEK293 cells. The 3D structure of ImKTx96 was constructed by molecular modeling, and the complex formed by ImKTx96 interacting with the Kv1.2 ion channel was obtained by molecular docking. Based on its structural features and pharmacological functions, ImKTx96 was identified as one member of K+-channel scorpion toxin α-KTx10 group and may be useful as a molecular probe for investigating the structure and function of the Kv1.2 ion channel.
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Affiliation(s)
- Sipian Li
- Department of Biochemistry, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, PR China
| | - Shuwen Sunchen
- Department of Biochemistry, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, PR China
| | - Dangui He
- State Key Laboratory of Virology, Renmin Hospital, Wuhan University, Wuhan 430072, PR China
| | - Chenhu Qin
- State Key Laboratory of Virology, Renmin Hospital, Wuhan University, Wuhan 430072, PR China
| | - Zheng Zuo
- State Key Laboratory of Virology, Renmin Hospital, Wuhan University, Wuhan 430072, PR China
| | - Bingzheng Shen
- State Key Laboratory of Virology, Renmin Hospital, Wuhan University, Wuhan 430072, PR China
| | - Zhijian Cao
- State Key Laboratory of Virology, Renmin Hospital, Wuhan University, Wuhan 430072, PR China; Hubei Province Engineering and Technology Research, Center for Fluorinated Pharmaceuticals, Wuhan University, Wuhan 430072, PR China
| | - Wei Hong
- State Key Laboratory of Virology, Renmin Hospital, Wuhan University, Wuhan 430072, PR China.
| | - Lixia Miao
- Department of Biochemistry, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, PR China.
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24
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Hamburger M. HPLC-based activity profiling for pharmacologically and toxicologically relevant natural products - principles and recent examples. Pharm Biol 2019; 57:328-334. [PMID: 31057026 PMCID: PMC6507960 DOI: 10.1080/13880209.2019.1606261] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 04/02/2019] [Indexed: 05/30/2023]
Abstract
CONTEXT Discovery of pharmacologically active natural products as starting points for drug development remains important and, for reasons of consumer safety, the identification of toxicologically relevant compounds in herbal drugs. OBJECTIVE To explain, with the aid of relevant examples from our own research, how these goals can be achieved. METHODS An in-house technology platform comprising pre-formatted extract libraries in 96-well format, miniaturized tracking of activity in extracts via HPLC-activity profiling, structure elucidation with microprobe NMR, and in vitro and in vivo pharmacological methods were used. RESULTS Piperine was identified as a new scaffold for allosteric GABAA receptor modulators with in vivo activity that interacts at a benzodiazepine-independent binding site. Selectivity and potency were improved by iterative optimization towards synthetic piperine analogues. Dehydroevodiamine and hortiamine from the traditional Chinese herbal drug Evodiae fructus were identified as potent hERG channel blockers in vitro. The compounds induced torsades de pointes arrhythmia in animal models. CONCLUSIONS The allosteric binding site for piperine analogues remains to be characterized and cardiac risks of herbal drugs need to be further evaluated to ensure consumer safety.
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Affiliation(s)
- Matthias Hamburger
- Pharmaceutical Biology, Pharmacenter, University of Basel, Basel, Switzerland
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25
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Cernuda B, Fernandes CT, Allam SM, Orzillo M, Suppa G, Chia Chang Z, Athanasopoulos D, Buraei Z. The molecular determinants of R-roscovitine block of hERG channels. PLoS One 2019; 14:e0217733. [PMID: 31479461 PMCID: PMC6719874 DOI: 10.1371/journal.pone.0217733] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 08/17/2019] [Indexed: 02/06/2023] Open
Abstract
Human ether-à-go-go-related gene (Kv11.1, or hERG) is a potassium channel that conducts the delayed rectifier potassium current (IKr) during the repolarization phase of cardiac action potentials. hERG channels have a larger pore than other K+channels and can trap many unintended drugs, often resulting in acquired LQTS (aLQTS). R-roscovitine is a cyclin-dependent kinase (CDK) inhibitor that induces apoptosis in colorectal, breast, prostate, multiple myeloma, other cancer cell lines, and tumor xenografts, in micromolar concentrations. It is well tolerated in phase II clinical trials. R-roscovitine inhibits open hERG channels but does not become trapped in the pore. Two-electrode voltage clamp recordings from Xenopus oocytes expressing wild-type (WT) or hERG pore mutant channels (T623A, S624A, Y652A, F656A) demonstrated that compared to WT hERG, T623A, Y652A, and F656A inhibition by 200 μM R-roscovitine was ~ 48%, 29%, and 73% weaker, respectively. In contrast, S624A hERG was inhibited more potently than WT hERG, with a ~ 34% stronger inhibition. These findings were further supported by the IC50 values, which were increased for T623A, Y652A and F656A (by ~5.5, 2.75, and 42 fold respectively) and reduced 1.3 fold for the S624A mutant. Our data suggest that while T623, Y652, and F656 are critical for R-roscovitine-mediated inhibition, S624 may not be. Docking studies further support our findings. Thus, R-roscovitine’s relatively unique features, coupled with its tolerance in clinical trials, could guide future drug screens.
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Affiliation(s)
- Bryan Cernuda
- Department of Biology, Pace University, New York, NY, United States of America
| | | | - Salma Mohamed Allam
- Department of Biology, Pace University, New York, NY, United States of America
| | - Matthew Orzillo
- Department of Biology, Pace University, New York, NY, United States of America
| | - Gabrielle Suppa
- Department of Biology, Pace University, New York, NY, United States of America
| | - Zuleen Chia Chang
- Department of Biology, Pace University, New York, NY, United States of America
| | | | - Zafir Buraei
- Department of Biology, Pace University, New York, NY, United States of America
- * E-mail:
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26
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Ekins S, Gerlach J, Zorn KM, Antonio BM, Lin Z, Gerlach A. Repurposing Approved Drugs as Inhibitors of K v7.1 and Na v1.8 to Treat Pitt Hopkins Syndrome. Pharm Res 2019; 36:137. [PMID: 31332533 DOI: 10.1007/s11095-019-2671-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 07/10/2019] [Indexed: 12/18/2022]
Abstract
PURPOSE Pitt Hopkins Syndrome (PTHS) is a rare genetic disorder caused by mutations of a specific gene, transcription factor 4 (TCF4), located on chromosome 18. PTHS results in individuals that have moderate to severe intellectual disability, with most exhibiting psychomotor delay. PTHS also exhibits features of autistic spectrum disorders, which are characterized by the impaired ability to communicate and socialize. PTHS is comorbid with a higher prevalence of epileptic seizures which can be present from birth or which commonly develop in childhood. Attenuated or absent TCF4 expression results in increased translation of peripheral ion channels Kv7.1 and Nav1.8 which triggers an increase in after-hyperpolarization and altered firing properties. METHODS We now describe a high throughput screen (HTS) of 1280 approved drugs and machine learning models developed from this data. The ion channels were expressed in either CHO (KV7.1) or HEK293 (Nav1.8) cells and the HTS used either 86Rb+ efflux (KV7.1) or a FLIPR assay (Nav1.8). RESULTS The HTS delivered 55 inhibitors of Kv7.1 (4.2% hit rate) and 93 inhibitors of Nav1.8 (7.2% hit rate) at a screening concentration of 10 μM. These datasets also enabled us to generate and validate Bayesian machine learning models for these ion channels. We also describe a structure activity relationship for several dihydropyridine compounds as inhibitors of Nav1.8. CONCLUSIONS This work could lead to the potential repurposing of nicardipine or other dihydropyridine calcium channel antagonists as potential treatments for PTHS acting via Nav1.8, as there are currently no approved treatments for this rare disorder.
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Affiliation(s)
- Sean Ekins
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina, 27606, USA.
| | - Jacob Gerlach
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina, 27606, USA
| | - Kimberley M Zorn
- Collaborations Pharmaceuticals, Inc., 840 Main Campus Drive, Lab 3510, Raleigh, North Carolina, 27606, USA
| | - Brett M Antonio
- Icagen, Inc., 4222 Emperor Blvd, Durham, North Carolina, 27703, USA
| | - Zhixin Lin
- Icagen, Inc., 4222 Emperor Blvd, Durham, North Carolina, 27703, USA
| | - Aaron Gerlach
- Icagen, Inc., 4222 Emperor Blvd, Durham, North Carolina, 27703, USA
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27
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Zhao Y, Chen Z, Cao Z, Li W, Wu Y. Diverse Structural Features of Potassium Channels Characterized by Scorpion Toxins as Molecular Probes. Molecules 2019; 24:molecules24112045. [PMID: 31146335 PMCID: PMC6600638 DOI: 10.3390/molecules24112045] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/15/2019] [Accepted: 05/26/2019] [Indexed: 12/21/2022] Open
Abstract
Scorpion toxins are well-known as the largest potassium channel peptide blocker family. They have been successfully proven to be valuable molecular probes for structural research on diverse potassium channels. The potassium channel pore region, including the turret and filter regions, is the binding interface for scorpion toxins, and structural features from different potassium channels have been identified using different scorpion toxins. According to the spatial orientation of channel turrets with differential sequence lengths and identities, conformational changes and molecular surface properties, the potassium channel turrets can be divided into the following three states: open state with less hindering effects on toxin binding, half-open state or half-closed state with certain effects on toxin binding, and closed state with remarkable effects on toxin binding. In this review, we summarized the diverse structural features of potassium channels explored using scorpion toxin tools and discuss future work in the field of scorpion toxin-potassium channel interactions.
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Affiliation(s)
- Yonghui Zhao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Zongyun Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China.
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Biodrug Research Center, Wuhan University, Wuhan 430072, China.
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Biodrug Research Center, Wuhan University, Wuhan 430072, China.
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Biodrug Research Center, Wuhan University, Wuhan 430072, China.
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28
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Ramírez D, Bedoya M, Kiper AK, Rinné S, Morales-Navarro S, Hernández-Rodríguez EW, Sepúlveda FV, Decher N, González W. Structure/Activity Analysis of TASK-3 Channel Antagonists Based on a 5,6,7,8 tetrahydropyrido[4,3-d]pyrimidine. Int J Mol Sci 2019; 20:ijms20092252. [PMID: 31067753 PMCID: PMC6539479 DOI: 10.3390/ijms20092252] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/18/2019] [Accepted: 04/20/2019] [Indexed: 11/16/2022] Open
Abstract
TASK-3 potassium (K+) channels are highly expressed in the central nervous system, regulating the membrane potential of excitable cells. TASK-3 is involved in neurotransmitter action and has been identified as an oncogenic K+ channel. For this reason, the understanding of the action mechanism of pharmacological modulators of these channels is essential to obtain new therapeutic strategies. In this study we describe the binding mode of the potent antagonist PK-THPP into the TASK-3 channel. PK-THPP blocks TASK-1, the closest relative channel of TASK-3, with almost nine-times less potency. Our results confirm that the binding is influenced by the fenestrations state of TASK-3 channels and occurs when they are open. The binding is mainly governed by hydrophobic contacts between the blocker and the residues of the binding site. These interactions occur not only for PK-THPP, but also for the antagonist series based on 5,6,7,8 tetrahydropyrido[4,3-d]pyrimidine scaffold (THPP series). However, the marked difference in the potency of THPP series compounds such as 20b, 21, 22 and 23 (PK-THPP) respect to compounds such as 17b, inhibiting TASK-3 channels in the micromolar range is due to the presence of a hydrogen bond acceptor group that can establish interactions with the threonines of the selectivity filter.
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Affiliation(s)
- David Ramírez
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile. El Llano Subercaseaux 2801-Piso 6, 7500912 Santiago, Chile.
| | - Mauricio Bedoya
- Centro de Bioinformática y Simulación Molecular (CBSM), Universidad de Talca. 1 Poniente No. 1141, 3460000 Talca, Chile.
| | - Aytug K Kiper
- Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Deutschhausstraße 2, 35037 Marburg, Germany.
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Deutschhausstraße 2, 35037 Marburg, Germany.
| | - Samuel Morales-Navarro
- Bachillerato en Ciencias, Facultad de Ciencias, Universidad Santo Tomás, Av. Circunvalación Poniente #1855, 3460000 Talca, Chile.
| | - Erix W Hernández-Rodríguez
- Centro de Bioinformática y Simulación Molecular (CBSM), Universidad de Talca. 1 Poniente No. 1141, 3460000 Talca, Chile.
- Escuela de Química y Farmacia. Facultad de Medicina. Universidad Católica del Maule, 3460000 Talca, Chile.
| | | | - Niels Decher
- Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Deutschhausstraße 2, 35037 Marburg, Germany.
| | - Wendy González
- Centro de Bioinformática y Simulación Molecular (CBSM), Universidad de Talca. 1 Poniente No. 1141, 3460000 Talca, Chile.
- Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Universidad de Talca, 3460000 Talca, Chile.
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Blaser A, Sutherland HS, Tong AST, Choi PJ, Conole D, Franzblau SG, Cooper CB, Upton AM, Lotlikar M, Denny WA, Palmer BD. Structure-activity relationships for unit C pyridyl analogues of the tuberculosis drug bedaquiline. Bioorg Med Chem 2019; 27:1283-1291. [PMID: 30792104 PMCID: PMC6467542 DOI: 10.1016/j.bmc.2019.02.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 01/30/2019] [Accepted: 02/14/2019] [Indexed: 11/30/2022]
Abstract
The ATP-synthase inhibitor bedaquiline is effective against drug-resistant tuberculosis but is extremely lipophilic (clogP 7.25) with a very long plasma half-life. Additionally, inhibition of potassium current through the cardiac hERG channel by bedaquiline, is associated with prolongation of the QT interval, necessitating cardiovascular monitoring. Analogues were prepared where the naphthalene C-unit was replaced with substituted pyridines to produce compounds with reduced lipophilicity, anticipating a reduction in half-life. While there was a direct correlation between in vitro inhibitory activity against M. tuberculosis (MIC90) and compound lipophilicity, potency only fell off sharply below a clogP of about 4.0, providing a useful lower bound for analogue design. The bulk of the compounds remained potent inhibitors of the hERG potassium channel, with notable exceptions where IC50 values were at least 5-fold higher than that of bedaquiline. Many of the compounds had desirably higher rates of clearance than bedaquiline, but this was associated with lower plasma exposures in mice, and similar or higher MICs resulted in lower AUC/MIC ratios than bedaquiline for most compounds. The two compounds with lower potency against hERG exhibited similar clearance to bedaquiline and excellent efficacy in vivo, suggesting further exploration of C-ring pyridyls is worthwhile.
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Affiliation(s)
- Adrian Blaser
- Auckland Cancer Society Research Centre, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Hamish S Sutherland
- Auckland Cancer Society Research Centre, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Amy S T Tong
- Auckland Cancer Society Research Centre, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Peter J Choi
- Auckland Cancer Society Research Centre, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Daniel Conole
- Auckland Cancer Society Research Centre, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Scott G Franzblau
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, IL 60612, USA
| | | | - Anna M Upton
- Global Alliance for TB Drug Development, 40 Wall Street, NY 10005, USA
| | - Manisha Lotlikar
- Global Alliance for TB Drug Development, 40 Wall Street, NY 10005, USA
| | - William A Denny
- Auckland Cancer Society Research Centre, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Maurice Wilkins Centre, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Brian D Palmer
- Auckland Cancer Society Research Centre, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Maurice Wilkins Centre, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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Manoukian OS, Arul MR, Rudraiah S, Kalajzic I, Kumbar SG. Aligned microchannel polymer-nanotube composites for peripheral nerve regeneration: Small molecule drug delivery. J Control Release 2019; 296:54-67. [PMID: 30658124 PMCID: PMC6379151 DOI: 10.1016/j.jconrel.2019.01.013] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 01/03/2019] [Accepted: 01/14/2019] [Indexed: 12/18/2022]
Abstract
Peripheral nerve injury accounts for roughly 2.8% of all trauma patients with an annual cost of 7 billion USD in the U.S. alone. Current treatment options rely on surgical intervention with the use of an autograft, despite associated shortcomings. Engineered nerve guidance conduits, stem cell therapies, and transient electrical stimulation have reported to increase speeds of functional recovery. As an alternative to the conduction effects of electrical stimulation, we have designed and optimized a nerve guidance conduit with aligned microchannels for the sustained release of a small molecule drug that promotes nerve impulse conduction. A biodegradable chitosan structure reinforced with drug-loaded halloysite nanotubes (HNT) was formed into a foam-like conduit with interconnected, longitudinally-aligned pores with an average pore size of 59.3 ± 14.2 μm. The aligned composite with HNTs produced anisotropic mechanical behavior with a Young's modulus of 0.33 ± 0.1 MPa, very similar to that of native peripheral nerve. This manuscript reports on the sustained delivery of 4-Aminopyridine (4AP, molecular weight 94.1146 g/mol), a potassium-channel blocker as a growth factor alternative to enhance the rate of nerve regeneration. The conduit formulation released a total of 30 ± 2% of the encapsulated 4AP in the first 7 days. Human Schwann cells showed elevated expression of key proteins such as nerve growth factor, myelin protein zero, and brain derived neurotrophic factor in a 4AP dose dependent manner. Preliminary in vivo studies in a critical-sized sciatic nerve defect in Wistar rats confirmed conduit suturability and strength to withstand ambulatory forces over 4 weeks of their implantation. Histological evaluations suggest conduit biocompatibility and Schwann cell infiltration and organization within the conduit and lumen. These nerve guidance conduits and 4AP sustained delivery may serve as an attractive strategy for nerve repair and regeneration.
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Affiliation(s)
- Ohan S Manoukian
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, USA; Department of Orthopaedic Surgery, University of Connecticut Health, Farmington, CT, USA
| | - Michael R Arul
- Department of Orthopaedic Surgery, University of Connecticut Health, Farmington, CT, USA
| | - Swetha Rudraiah
- Department of Orthopaedic Surgery, University of Connecticut Health, Farmington, CT, USA; Department of Pharmaceutical Sciences, University of Saint Joseph, Hartford, CT, USA
| | - Ivo Kalajzic
- Department of Reconstructive Sciences, University of Connecticut Health, Farmington, CT, USA
| | - Sangamesh G Kumbar
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, USA; Department of Orthopaedic Surgery, University of Connecticut Health, Farmington, CT, USA.
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Pugsley MK, Yong SL, Goldin AL, Hayes ES, Walker MJA. Molecular charge associated with antiarrhythmic actions in a series of amino-2-cyclohexyl ester derivatives. Eur J Pharmacol 2019; 844:241-252. [PMID: 30571955 DOI: 10.1016/j.ejphar.2018.12.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 11/12/2018] [Accepted: 12/12/2018] [Indexed: 11/15/2022]
Abstract
A series of amino-2-cyclohexyl ester derivatives were studied for their ion channel blocking and antiarrhythmic actions in the rat and a structure-activity analysis was conducted. The compounds are similar in chemical structure except for ionizable amine groups (pK values 6.1-8.9) and the positional arrangements of aromatic naphthyl moieties. Ventricular arrhythmias were produced in rats by coronary-artery occlusion or electrical stimulation. The electrophysiological effects of these compounds on rat heart sodium channels (Nav1.5) expressed in Xenopus laevis oocytes and transient outward potassium currents (Kv4.3) from isolated rat ventricular myocytes were examined. The compounds reduced the incidence of ischemia-related arrhythmias and increased current threshold for induction of ventricular fibrillo-flutter (VFt) dose-dependently. As pK increased compounds showed a diminished effectiveness against ischemia-induced arrhythmias, and were less selective for ischemia- versus electrically-induced arrhythmias. Where tested, compounds produced a concentration-dependent tonic block of Nav1.5 channels. An increased potency for inhibition of Nav1.5 occurred when the external pH (pHo) was reduced to 6.5. Some compounds inhibited Kv4.3 in a pH-independent manner. Overall, the differences in antiarrhythmic and ion channel blocking properties in this series of compounds can be explained by differences in chemical structure. Antiarrhythmic activity for the amino-2-cyclohexyl ester derivatives is likely a function of mixed ion channel blockade in ischemic myocardium. These studies show that drug inhibition of Nav1.5 occurred at lower concentrations than Kv4.3 and was more sensitive to changes in the ionizable amine groups rather than on positional arrangements of the naphthyl constituents. These results offer insight into antiarrhythmic mechanisms of drug-ion channel interactions.
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Affiliation(s)
- Michael K Pugsley
- Safety Pharmacology & Toxicology, Fairfield, CT 06825, USA; Department of Pharmacology & Therapeutics, Faculty of Medicine, The University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, Canada, V6T 1Z3.
| | - Sandro L Yong
- Department of Pharmacology & Therapeutics, Faculty of Medicine, The University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, Canada, V6T 1Z3
| | - Alan L Goldin
- Department of Microbiology & Molecular Genetics, University of California, Irvine, California, CA 92697-4025, USA
| | - Eric S Hayes
- BioCurate Pty Ltd., Parkville, Victoria, Australia
| | - Michael J A Walker
- Department of Pharmacology & Therapeutics, Faculty of Medicine, The University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, Canada, V6T 1Z3
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Bassetto Junior CAZ, Passianoto LVG, González ERP, Varanda WA. Benzenesulfonamides act as open-channel blockers on K V3.1 potassium channel. Amino Acids 2019; 51:355-364. [PMID: 30361851 DOI: 10.1007/s00726-018-2669-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 10/19/2018] [Indexed: 10/28/2022]
Abstract
KV3.1 blockers can serve as modulators of the rate of action potential firing in neurons with high rates of firing such as those of the auditory system. We studied the effects of several bioisosteres of N-alkylbenzenesulfonamides, and molecules derived from sulfanilic acid on KV3.1 channels, heterologously expressed in L-929 cells, using the whole-cell patch-clamp technique. Only the N-alkyl-benzenesulfonamides acted as open-channel blockers on KV3.1, while molecules analogous to PABA (p-aminobenzoic acid) and derived from sulfanilic acids did not block the channel. The IC50 of six N-alkyl-benzenesulfonamides ranged from 9 to 55 µM; and the Hill coefficient suggests the binding of two molecules to block KV3.1. Also, the effects of all molecules on KV3.1 were fully reversible. We look for similar features amongst the molecules that effectively blocked the channel and used them to model a blocker prototype. We found that bulkier groups and amino-lactams decreased the effectiveness of the blockage, while the presence of NO2 increased the effectiveness of the blockage. Thus, we propose N-alkylbenzenesulfonamides as a new class of KV3.1 channel blockers.
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Affiliation(s)
- Carlos Alberto Zanutto Bassetto Junior
- Fine Organic Chemistry Laboratory, Department of Chemistry and Biochemistry, Faculty of Science and Technology, São Paulo State University (Unesp)-Campus of Presidente Prudente, São Paulo, SP, CEP 19060-900, Brazil
| | - Luana Vitorino Gushiken Passianoto
- Fine Organic Chemistry Laboratory, Department of Chemistry and Biochemistry, Faculty of Science and Technology, São Paulo State University (Unesp)-Campus of Presidente Prudente, São Paulo, SP, CEP 19060-900, Brazil
| | - Eduardo René Pérez González
- Fine Organic Chemistry Laboratory, Department of Chemistry and Biochemistry, Faculty of Science and Technology, São Paulo State University (Unesp)-Campus of Presidente Prudente, São Paulo, SP, CEP 19060-900, Brazil.
| | - Wamberto Antonio Varanda
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
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Kúsz N, Orvos P, Bereczki L, Fertey P, Bombicz P, Csorba A, Tálosi L, Jakab G, Hohmann J, Rédei D. Diterpenoids from Euphorbia dulcis with Potassium Ion Channel Inhibitory Activity with Selective G Protein-Activated Inwardly Rectifying Ion Channel (GIRK) Blocking Effect. J Nat Prod 2018; 81:2483-2492. [PMID: 30411614 DOI: 10.1021/acs.jnatprod.8b00500] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Nine new (1-9) and two known (10, 11) jatrophane diterpenoids were isolated from the methanol extract of Euphorbia dulcis. The structure elucidation of the compounds was performed by means of extensive spectroscopic analysis, including HRESIMS, 1D (1H, JMOD), and 2D (HSQC, HMBC, 1H-1H-COSY, NOESY) NMR experiments. The absolute configuration of compound 1 was determined by single-crystal X-ray diffraction. The electrophysiological effects of compounds 1-11 and the five diterpenoids (12-16) previously isolated from Euphorbia taurinensis were investigated on stable transfected HEK-GIRK1/4 (Kir3.1/3.4) and HEK-hERG (Kv11.1) cell lines using automated patch-clamp equipment. The majority of the diterpenoids showed significant blocking activity on GIRK channels (60.8-88.7% at 10 μM), while compounds 1, 2, 9-11, 13, and 14 exerted notable inhibitory effects even at 1 μM concentration. None of the jatrophane diterpenoids interfered with the function of hERG proteins; however, compound 14 remarkably hampered K+ flow through hERG channels. These selective activities suggest that jatrophane diterpenoids may represent a group of potential lead compounds for the development of novel therapeutic agents against atrial fibrillation.
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Affiliation(s)
| | | | - Laura Bereczki
- Research Centre for Natural Sciences , Hungarian Academy of Sciences , 1117 Budapest , Hungary
| | - Pierre Fertey
- Synchrotron SOLEIL L'Orme des Merisiers-Saint Aubin , B.P. 4891 192 Gif-sur-Yvette Cedex , France
| | - Petra Bombicz
- Research Centre for Natural Sciences , Hungarian Academy of Sciences , 1117 Budapest , Hungary
| | | | | | - Gusztáv Jakab
- Institute of Environmental Sciences, Faculty of Water and Environmental Management , Szent István University , 5540 Szarvas , Hungary
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Zhao Y, Chen Z, Cao Z, Li W, Wu Y. Defensins, a novel type of animal toxin-like potassium channel inhibitor. Toxicon 2018; 157:101-105. [PMID: 30472109 DOI: 10.1016/j.toxicon.2018.11.304] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 11/03/2018] [Accepted: 11/19/2018] [Indexed: 12/29/2022]
Abstract
The classical potassium channel inhibitors are toxin peptides from venomous animals, and whether there are peptide inhibitors from other species is an open question. Due to both the independent and interdependent relationships between the spear (peptide inhibitors) and the shield (potassium channels), human defensins were first identified by our group as endogenous potassium channel inhibitors. Encouraged by the discovery of human defensins as potassium channel inhibitors, defensins from invertebrates and fungi were successively found by our group to be potassium channel inhibitors. In addition, a plant defensin was reported to be a potassium channel inhibitor. Since defensins are widely produced by vertebrate, invertebrate, plant and fungi species, the recent work established a new research field on defensin-potassium channel interactions. Here, we review the current work on defensins from vertebrate, invertebrate, plant and fungi species as inhibitors of potassium channels and discuss future work in this research field.
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Affiliation(s)
- Yonghui Zhao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Zongyun Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China; Department of Biochemistry and Molecular Biology, College of Basic Medicine, Hubei University of Medicine, Hubei, China
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China; Biodrug Research Center, Wuhan University, Wuhan, 430072, China
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China; Biodrug Research Center, Wuhan University, Wuhan, 430072, China
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China; Biodrug Research Center, Wuhan University, Wuhan, 430072, China.
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Assis KS, Araújo IGA, de Azevedo FDLAA, Maciel PMP, Machado Calzerra NT, da Silva TAF, Assis VL, de Vasconcelos AP, Santos CAG, Meireles BRLA, Cordeiro AMTM, Araújo DAM, Ribeiro TP, Medeiros IA. Potassium Channel Activation Is Involved in the Cardiovascular Effects Induced by Freeze Dried Syzygium jambolanum (Lam.) DC Fruit Juice. Biomed Res Int 2018; 2018:4827461. [PMID: 30402480 PMCID: PMC6196999 DOI: 10.1155/2018/4827461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 07/25/2018] [Accepted: 09/03/2018] [Indexed: 11/17/2022]
Abstract
This work aimed to explore the cardiovascular effects induced by freeze-dried juice from Syzygium jambolanum (Lam.) DC fruits (JSJ). JSJ presented high polyphenol content and steroids. HPLC analysis revealed that 2,5-dihydroxybenzoic and caffeic acid were present in higher amounts in the JSJ extract. In rat, JSJ induces hypotension and vasodilatation in mesenteric arteries, with or without vascular endothelium. JSJ-mediated vasodilation response against contractions induced with KCl (60 mM) depolarizing solution was significantly lower than the responses induced by JSJ when evaluated against phenylephrine-induced contractions. To investigate the involvement of potassium channels we used Tyrode's solution with KCl (20 mM) or tetraethylammonium (1.0, 3.0, or 5.0 mM). In these conditions JSJ-induced effects were significantly attenuated. To investigate the potassium channel subtypes involved in the response, we used 4-aminopyridine, glibenclamide, BaCl2, and iberiotoxin. In the presence (simultaneous) of different potassium channel blockers we observed a significant attenuation of JSJ-induced effect. Inhibition was also observed when using BaCl2, glibenclamide, or 4-aminopyridine, separately. However, incubation with iberiotoxin did not promote changes in either maximum effect, or potency. We also evidenced a discrete participation of CaV channels in the JSJ-induced vasorelaxant effect. In addition, patch-clamp studies demonstrated that JSJ could activate potassium channels. In conclusion, JSJ promotes hypotension and vasorelaxation in rats, involving, at least, the activation of potassium channels.
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Affiliation(s)
- Kívia S. Assis
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos/Centro de Ciências da Saúde (CCS)/Universidade Federal da Paraíba (UFPB), João Pessoa 58059-900, Brazil
| | - Islania G. A. Araújo
- Departamento de Ciências Farmacêuticas, (CCS)/Universidade Federal da Paraíba (UFPB), João Pessoa 58059-900, Brazil
| | - Fátima de L. A. A. de Azevedo
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos/Centro de Ciências da Saúde (CCS)/Universidade Federal da Paraíba (UFPB), João Pessoa 58059-900, Brazil
| | - Priscilla M. P. Maciel
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos/Centro de Ciências da Saúde (CCS)/Universidade Federal da Paraíba (UFPB), João Pessoa 58059-900, Brazil
| | - Natália T. Machado Calzerra
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos/Centro de Ciências da Saúde (CCS)/Universidade Federal da Paraíba (UFPB), João Pessoa 58059-900, Brazil
| | - Tays A. F. da Silva
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos/Centro de Ciências da Saúde (CCS)/Universidade Federal da Paraíba (UFPB), João Pessoa 58059-900, Brazil
| | - Valéria L. Assis
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos/Centro de Ciências da Saúde (CCS)/Universidade Federal da Paraíba (UFPB), João Pessoa 58059-900, Brazil
| | - Aliny P. de Vasconcelos
- Departamento de Biotecnologia, Centro de Biotecnologia/Universidade Federal da Paraíba (UFPB), João Pessoa 58059-900, Brazil
| | - Carlos A. G. Santos
- Centro de Educação e Saúde, Unidade Acadêmica de Biologia e Química, Universidade Federal de Campina Grande (UFCG) Cuité, Paraíba, 58750-000, Brazil
| | - Bruno R. L. A. Meireles
- Departamento de Tecnologia de Alimentos, Centro de Tecnologia e Desenvolvimento Regional - CTDR, Universidade Federal de Paraíba, João Pessoa, Paraíba, Brazil
| | - Angela M. T. M. Cordeiro
- Centro de Educação e Saúde, Unidade Acadêmica de Biologia e Química, Universidade Federal de Campina Grande (UFCG) Cuité, Paraíba, 58750-000, Brazil
| | - Demetrius A. M. Araújo
- Departamento de Biotecnologia, Centro de Biotecnologia/Universidade Federal da Paraíba (UFPB), João Pessoa 58059-900, Brazil
| | - Thais P. Ribeiro
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos/Centro de Ciências da Saúde (CCS)/Universidade Federal da Paraíba (UFPB), João Pessoa 58059-900, Brazil
| | - Isac A. Medeiros
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos/Centro de Ciências da Saúde (CCS)/Universidade Federal da Paraíba (UFPB), João Pessoa 58059-900, Brazil
- Departamento de Ciências Farmacêuticas, (CCS)/Universidade Federal da Paraíba (UFPB), João Pessoa 58059-900, Brazil
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B Orts DJ, Peigneur S, Silva-Gonçalves LC, Arcisio-Miranda M, P W Bicudo JE, Tytgat J. AbeTx1 Is a Novel Sea Anemone Toxin with a Dual Mechanism of Action on Shaker-Type K⁺ Channels Activation. Mar Drugs 2018; 16:md16100360. [PMID: 30275388 PMCID: PMC6213216 DOI: 10.3390/md16100360] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 09/25/2018] [Accepted: 09/29/2018] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated potassium (KV) channels regulate diverse physiological processes and are an important target for developing novel therapeutic approaches. Sea anemone (Cnidaria, Anthozoa) venoms comprise a highly complex mixture of peptide toxins with diverse and selective pharmacology on KV channels. From the nematocysts of the sea anemone Actinia bermudensis, a peptide that we named AbeTx1 was purified and functionally characterized on 12 different subtypes of KV channels (KV1.1⁻KV1.6; KV2.1; KV3.1; KV4.2; KV4.3; KV11.1; and, Shaker IR), and three voltage-gated sodium channel isoforms (NaV1.2, NaV1.4, and BgNaV). AbeTx1 was selective for Shaker-related K⁺ channels and is capable of inhibiting K⁺ currents, not only by blocking the K⁺ current of KV1.2 subtype, but by altering the energetics of activation of KV1.1 and KV1.6. Moreover, experiments using six synthetic alanine point-mutated analogs further showed that a ring of basic amino acids acts as a multipoint interaction for the binding of the toxin to the channel. The AbeTx1 primary sequence is composed of 17 amino acids with a high proportion of lysines and arginines, including two disulfide bridges (Cys1⁻Cys4 and Cys2⁻Cys3), and it is devoid of aromatic or aliphatic amino acids. Secondary structure analysis reveals that AbeTx1 has a highly flexible, random-coil-like conformation, but with a tendency of structuring in the beta sheet. Its overall structure is similar to open-ended cyclic peptides found on the scorpion κ-KTx toxins family, cone snail venoms, and antimicrobial peptides.
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Affiliation(s)
- Diego J B Orts
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, Brazil.
| | - Steve Peigneur
- Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium.
| | - Laíz Costa Silva-Gonçalves
- Laboratório de Neurobiologia Estrutural e Funcional (LaNEF), Departamento de Biofísica, Universidade Federal de São Paulo, 04023-062 São Paulo, Brazil.
| | - Manoel Arcisio-Miranda
- Laboratório de Neurobiologia Estrutural e Funcional (LaNEF), Departamento de Biofísica, Universidade Federal de São Paulo, 04023-062 São Paulo, Brazil.
| | - José Eduardo P W Bicudo
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, Brazil.
| | - Jan Tytgat
- Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium.
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Romero-Gutiérrez MT, Santibáñez-López CE, Jiménez-Vargas JM, Batista CVF, Ortiz E, Possani LD. Transcriptomic and Proteomic Analyses Reveal the Diversity of Venom Components from the Vaejovid Scorpion Serradigitus gertschi. Toxins (Basel) 2018; 10:E359. [PMID: 30189638 PMCID: PMC6162517 DOI: 10.3390/toxins10090359] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 08/29/2018] [Accepted: 09/01/2018] [Indexed: 12/22/2022] Open
Abstract
To understand the diversity of scorpion venom, RNA from venomous glands from a sawfinger scorpion, Serradigitus gertschi, of the family Vaejovidae, was extracted and used for transcriptomic analysis. A total of 84,835 transcripts were assembled after Illumina sequencing. From those, 119 transcripts were annotated and found to putatively code for peptides or proteins that share sequence similarities with the previously reported venom components of other species. In accordance with sequence similarity, the transcripts were classified as potentially coding for 37 ion channel toxins; 17 host defense peptides; 28 enzymes, including phospholipases, hyaluronidases, metalloproteases, and serine proteases; nine protease inhibitor-like peptides; 10 peptides of the cysteine-rich secretory proteins, antigen 5, and pathogenesis-related 1 protein superfamily; seven La1-like peptides; and 11 sequences classified as "other venom components". A mass fingerprint performed by mass spectrometry identified 204 components with molecular masses varying from 444.26 Da to 12,432.80 Da, plus several higher molecular weight proteins whose precise masses were not determined. The LC-MS/MS analysis of a tryptic digestion of the soluble venom resulted in the de novo determination of 16,840 peptide sequences, 24 of which matched sequences predicted from the translated transcriptome. The database presented here increases our general knowledge of the biodiversity of venom components from neglected non-buthid scorpions.
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Affiliation(s)
- Maria Teresa Romero-Gutiérrez
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Apartado Postal 510-3, Cuernavaca, Morelos 62210, Mexico.
| | - Carlos Eduardo Santibáñez-López
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Apartado Postal 510-3, Cuernavaca, Morelos 62210, Mexico.
- Department of Integrative Biology, University of Wisconsin⁻Madison, Madison, WI 53706, USA.
| | - Juana María Jiménez-Vargas
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Apartado Postal 510-3, Cuernavaca, Morelos 62210, Mexico.
| | - Cesar Vicente Ferreira Batista
- Laboratorio Universitario de Proteómica, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Apartado Postal 510-3, Cuernavaca, Morelos 62210, Mexico.
| | - Ernesto Ortiz
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Apartado Postal 510-3, Cuernavaca, Morelos 62210, Mexico.
| | - Lourival Domingos Possani
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Apartado Postal 510-3, Cuernavaca, Morelos 62210, Mexico.
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Abstract
The inhibition of the hERG potassium channel is closely related to the prolonged QT interval, and thus assessing this risk could greatly facilitate the development of therapeutic compounds and the withdrawal of hazardous marketed drugs. The recent increase in SAR information about hERG inhibitors in public databases has led to many successful applications of machine learning techniques to predict hERG inhibition. However, most of these reports constructed their prediction models based on only one SAR database because the differences in the data format and ontology hindered the integration of the databases. In this study, we curated the hERG-related data in ChEMBL, PubChem, GOSTAR, and hERGCentral, and integrated them into the largest database about hERG inhibition by small molecules. Assessment of structural diversity using Murcko frameworks revealed that the integrated database contains more than twice as many chemical scaffolds for hERG inhibitors than any of the individual databases, and covers 18.2% of the Murcko framework-based chemical space occupied by the compounds in ChEMBL. The database provides the most comprehensive information about hERG inhibitors and will be useful to design safer compounds for drug discovery. The database is freely available at http://drugdesign.riken.jp/hERGdb/.
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Affiliation(s)
- Tomohiro Sato
- Center for Life Science Technologies, RIKEN, Suehiro-cho, Tsurumi-ku, Yokohama City, Kanagawa, Japan
| | - Hitomi Yuki
- Center for Life Science Technologies, RIKEN, Suehiro-cho, Tsurumi-ku, Yokohama City, Kanagawa, Japan
| | - Keiji Ogura
- Center for Life Science Technologies, RIKEN, Suehiro-cho, Tsurumi-ku, Yokohama City, Kanagawa, Japan
| | - Teruki Honma
- Center for Life Science Technologies, RIKEN, Suehiro-cho, Tsurumi-ku, Yokohama City, Kanagawa, Japan
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Prentis PJ, Pavasovic A, Norton RS. Sea Anemones: Quiet Achievers in the Field of Peptide Toxins. Toxins (Basel) 2018; 10:toxins10010036. [PMID: 29316700 PMCID: PMC5793123 DOI: 10.3390/toxins10010036] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 01/04/2018] [Accepted: 01/04/2018] [Indexed: 01/09/2023] Open
Abstract
Sea anemones have been understudied as a source of peptide and protein toxins, with relatively few examined as a source of new pharmacological tools or therapeutic leads. This is surprising given the success of some anemone peptides that have been tested, such as the potassium channel blocker from Stichodactyla helianthus known as ShK. An analogue of this peptide, ShK-186, which is now known as dalazatide, has successfully completed Phase 1 clinical trials and is about to enter Phase 2 trials for the treatment of autoimmune diseases. One of the impediments to the exploitation of sea anemone toxins in the pharmaceutical industry has been the difficulty associated with their high-throughput discovery and isolation. Recent developments in multiple ‘omic’ technologies, including genomics, transcriptomics and proteomics, coupled with advanced bioinformatics, have opened the way for large-scale discovery of novel sea anemone toxins from a range of species. Many of these toxins will be useful pharmacological tools and some will hopefully prove to be valuable therapeutic leads.
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Affiliation(s)
- Peter J Prentis
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology (QUT), Brisbane, QLD 4001, Australia.
- Institute of Future Environments, Queensland University of Technology (QUT), Brisbane, QLD 4001, Australia.
| | - Ana Pavasovic
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology (QUT), Brisbane, QLD 4001, Australia.
- Faculty of Health, Queensland University of Technology (QUT), Brisbane, QLD 4001, Australia.
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
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Krishnarjuna B, MacRaild CA, Sunanda P, Morales RAV, Peigneur S, Macrander J, Yu HH, Daly M, Raghothama S, Dhawan V, Chauhan S, Tytgat J, Pennington MW, Norton RS. Structure, folding and stability of a minimal homologue from Anemonia sulcata of the sea anemone potassium channel blocker ShK. Peptides 2018; 99:169-178. [PMID: 28993277 DOI: 10.1016/j.peptides.2017.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 10/03/2017] [Accepted: 10/05/2017] [Indexed: 01/01/2023]
Abstract
Peptide toxins elaborated by sea anemones target various ion-channel sub-types. Recent transcriptomic studies of sea anemones have identified several novel candidate peptides, some of which have cysteine frameworks identical to those of previously reported sequences. One such peptide is AsK132958, which was identified in a transcriptomic study of Anemonia sulcata and has a cysteine framework similar to that of ShK from Stichodactyla helianthus, but is six amino acid residues shorter. We have determined the solution structure of this novel peptide using NMR spectroscopy. The disulfide connectivities and structural scaffold of AsK132958 are very similar to those of ShK but the structure is more constrained. Toxicity assays were performed using grass shrimp (Palaemonetes sp) and Artemia nauplii, and patch-clamp electrophysiology assays were performed to assess the activity of AsK132958 against a range of voltage-gated potassium (KV) channels. AsK132958 showed no activity against grass shrimp, Artemia nauplii, or any of the KV channels tested, owing partly to the absence of a functional Lys-Tyr dyad. Three AsK132958 analogues, each containing a Tyr in the vicinity of Lys19, were therefore generated in an effort to restore binding, but none showed activity against any of KV channels tested. However, AsK132958 and its analogues are less susceptible to proteolysis than that of ShK. Our structure suggests that Lys19, which might be expected to occupy the pore of the channel, is not sufficiently accessible for binding, and therefore that AsK132958 must have a distinct functional role that does not involve KV channels.
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Affiliation(s)
- Bankala Krishnarjuna
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Christopher A MacRaild
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Punnepalli Sunanda
- NMR Research Centre, Indian Institute of Science, Bangalore 560012, India
| | - Rodrigo A V Morales
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Steve Peigneur
- Toxicology and Pharmacology, University of Leuven, O&N 2, Herestraat 49, P.O. Box 922, 3000, Leuven, Belgium
| | - Jason Macrander
- Department of Evolution, Ecology, Organismal Biology, Ohio State University, 1315 Kinnear Rd, Columbus, OH 43212, USA; Department of Biology, University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC 28223, USA
| | - Heidi H Yu
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, VIC 3800, Australia
| | - Marymegan Daly
- Department of Evolution, Ecology, Organismal Biology, Ohio State University, 1315 Kinnear Rd, Columbus, OH 43212, USA
| | | | - Vikas Dhawan
- Peptides International, Louisville, KY 40299, USA
| | | | - Jan Tytgat
- Toxicology and Pharmacology, University of Leuven, O&N 2, Herestraat 49, P.O. Box 922, 3000, Leuven, Belgium
| | | | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia.
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Diesch AK, Grissmer S. Kinetic Aspects of Verapamil Binding (On-Rate) on Wild-Type and Six hKv1.3 Mutant Channels. Cell Physiol Biochem 2017; 44:172-184. [PMID: 29131061 DOI: 10.1159/000484625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 10/14/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS The human-voltage gated Kv1.3 channel (hKv1.3) is expressed in T- and B lymphocytes. Verapamil is able to block hKv1.3 channels. We characterized the effect of verapamil on currents through hKv1.3 channels paying special attention to the on-rate (kon) of verapamil. By comparing on-rates obtained in wild-type (wt) and mutant channels a binding pocket for verapamil and impacts of different amino acid residues should be investigated. METHODS Using the whole-cell patch clamp technique the action of verapamil on currents through wild-type and six hKv1.3 mutant channels in the open state was investigated by measuring the time course of the open channel block in order to calculate kon of verapamil. RESULTS The on-rate of verapamil to block current through hKv1.3_T419C mutant channels is similar to that obtained for hKv1.3_wt channels whereas the on-rate of verapamil to block currents through hKv1.3_L417C and hKv1.3_L418C mutant channels was ∼ 3 times slower compared to in wt channels. The on-rate of verapamil to block currents through hKv1.3_L346C and the double mutant hKv1.3_L346C_L418C channel was ∼ 2 times slower compared to that obtained in the wt channel. The hKv1.3_I420C mutant channel reduced the on-rate of verapamil to block currents ∼ 6 fold. CONCLUSIONS We conclude that position 420 in hKv1.3 channels maximally interferes with verapamil reaching its binding site to block the channel. Positions 417 and 418 in hKv1.3 channels partially hinder verapamil reaching its binding site to block the channel whereas position 419 may not interfere with verapamil at all. Mutant hKv1.3_L346C and hKv1.3_L346C_L418C mutant channels might indirectly influence the ability of verapamil reaching its binding site to block current.
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Ji Y, Veldhuis MG, Zandvoort J, Romunde FL, Houtman MJC, Duran K, van Haaften G, Zangerl-Plessl EM, Takanari H, Stary-Weinzinger A, van der Heyden MAG. PA-6 inhibits inward rectifier currents carried by V93I and D172N gain-of-function K IR2.1 channels, but increases channel protein expression. J Biomed Sci 2017; 24:44. [PMID: 28711067 PMCID: PMC5513211 DOI: 10.1186/s12929-017-0352-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/11/2017] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND The inward rectifier potassium current IK1 contributes to a stable resting membrane potential and phase 3 repolarization of the cardiac action potential. KCNJ2 gain-of-function mutations V93I and D172N associate with increased IK1, short QT syndrome type 3 and congenital atrial fibrillation. Pentamidine-Analogue 6 (PA-6) is an efficient (IC50 = 14 nM with inside-out patch clamp methodology) and specific IK1 inhibitor that interacts with the cytoplasmic pore region of the KIR2.1 ion channel, encoded by KCNJ2. At 10 μM, PA-6 increases wild-type (WT) KIR2.1 expression in HEK293T cells upon chronic treatment. We hypothesized that PA-6 will interact with and inhibit V93I and D172N KIR2.1 channels, whereas impact on channel expression at the plasma membrane requires higher concentrations. METHODS Molecular modelling was performed with the human KIR2.1 closed state homology model using FlexX. WT and mutant KIR2.1 channels were expressed in HEK293 cells. Patch-clamp single cell electrophysiology measurements were performed in the whole cell and inside-out mode of the patch clamp method. KIR2.1 expression level and localization were determined by western blot analysis and immunofluorescence microscopy, respectively. RESULTS PA-6 docking in the V93I/D172N double mutant homology model of KIR2.1 demonstrated that mutations and drug-binding site are >30 Å apart. PA-6 inhibited WT and V93I outward currents with similar potency (IC50 = 35.5 and 43.6 nM at +50 mV for WT and V93I), whereas D172N currents were less sensitive (IC50 = 128.9 nM at +50 mV) using inside-out patch-clamp electrophysiology. In whole cell mode, 1 μM of PA-6 inhibited outward IK1 at -50 mV by 28 ± 36%, 18 ± 20% and 10 ± 6%, for WT, V93I and D172N channels respectively. Western blot analysis demonstrated that PA-6 (5 μM, 24 h) increased KIR2.1 expression levels of WT (6.3 ± 1.5 fold), and V93I (3.9 ± 0.9) and D172N (4.8 ± 2.0) mutants. Immunofluorescent microscopy demonstrated dose-dependent intracellular KIR2.1 accumulation following chronic PA-6 application (24 h, 1 and 5 μM). CONCLUSIONS 1) KCNJ2 gain-of-function mutations V93I and D172N in the KIR2.1 ion channel do not impair PA-6 mediated inhibition of IK1, 2) PA-6 elevates KIR2.1 protein expression and induces intracellular KIR2.1 accumulation, 3) PA-6 is a strong candidate for further preclinical evaluation in treatment of congenital SQT3 and AF.
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Affiliation(s)
- Yuan Ji
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Marlieke G. Veldhuis
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Jantien Zandvoort
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Fee L. Romunde
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Marien J. C. Houtman
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Karen Duran
- Center for Molecular Medicine, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Gijs van Haaften
- Center for Molecular Medicine, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Hiroki Takanari
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | | | - Marcel A. G. van der Heyden
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
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Leanza L, Romio M, Becker KA, Azzolini M, Trentin L, Managò A, Venturini E, Zaccagnino A, Mattarei A, Carraretto L, Urbani A, Kadow S, Biasutto L, Martini V, Severin F, Peruzzo R, Trimarco V, Egberts JH, Hauser C, Visentin A, Semenzato G, Kalthoff H, Zoratti M, Gulbins E, Paradisi C, Szabo I. Direct Pharmacological Targeting of a Mitochondrial Ion Channel Selectively Kills Tumor Cells In Vivo. Cancer Cell 2017; 31:516-531.e10. [PMID: 28399409 DOI: 10.1016/j.ccell.2017.03.003] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 02/03/2017] [Accepted: 03/07/2017] [Indexed: 12/13/2022]
Abstract
The potassium channel Kv1.3 is highly expressed in the mitochondria of various cancerous cells. Here we show that direct inhibition of Kv1.3 using two mitochondria-targeted inhibitors alters mitochondrial function and leads to reactive oxygen species (ROS)-mediated death of even chemoresistant cells independently of p53 status. These inhibitors killed 98% of ex vivo primary chronic B-lymphocytic leukemia tumor cells while sparing healthy B cells. In orthotopic mouse models of melanoma and pancreatic ductal adenocarcinoma, the compounds reduced tumor size by more than 90% and 60%, respectively, while sparing immune and cardiac functions. Our work provides direct evidence that specific pharmacological targeting of a mitochondrial potassium channel can lead to ROS-mediated selective apoptosis of cancer cells in vivo, without causing significant side effects.
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Affiliation(s)
- Luigi Leanza
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Matteo Romio
- Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35121 Padova, Italy
| | - Katrin Anne Becker
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Michele Azzolini
- Department of Biomedical Sciences, University of Padova, viale G. Colombo 3, 35121 Padova, Italy; CNR Institute of Neuroscience, viale G. Colombo 3, 35121 Padova, Italy
| | - Livio Trentin
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Antonella Managò
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Elisa Venturini
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Angela Zaccagnino
- Institute for Experimental Cancer Research, Medical Faculty, CAU, Kiel, and Department of Surgery, UKSH, Campus Kiel, Arnold-Heller-Strasse 3 (Haus 17), 24105 Kiel, Germany
| | - Andrea Mattarei
- Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35121 Padova, Italy
| | - Luca Carraretto
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Andrea Urbani
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Stephanie Kadow
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Lucia Biasutto
- Department of Biomedical Sciences, University of Padova, viale G. Colombo 3, 35121 Padova, Italy; CNR Institute of Neuroscience, viale G. Colombo 3, 35121 Padova, Italy
| | - Veronica Martini
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Filippo Severin
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Roberta Peruzzo
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Valentina Trimarco
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Jan-Hendrik Egberts
- Institute for Experimental Cancer Research, Medical Faculty, CAU, Kiel, and Department of Surgery, UKSH, Campus Kiel, Arnold-Heller-Strasse 3 (Haus 17), 24105 Kiel, Germany
| | - Charlotte Hauser
- Institute for Experimental Cancer Research, Medical Faculty, CAU, Kiel, and Department of Surgery, UKSH, Campus Kiel, Arnold-Heller-Strasse 3 (Haus 17), 24105 Kiel, Germany
| | - Andrea Visentin
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Gianpietro Semenzato
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Holger Kalthoff
- Institute for Experimental Cancer Research, Medical Faculty, CAU, Kiel, and Department of Surgery, UKSH, Campus Kiel, Arnold-Heller-Strasse 3 (Haus 17), 24105 Kiel, Germany
| | - Mario Zoratti
- Department of Biomedical Sciences, University of Padova, viale G. Colombo 3, 35121 Padova, Italy; CNR Institute of Neuroscience, viale G. Colombo 3, 35121 Padova, Italy
| | - Erich Gulbins
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany; Department of Surgery, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0558, USA.
| | - Cristina Paradisi
- Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35121 Padova, Italy.
| | - Ildiko Szabo
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy; CNR Institute of Neuroscience, viale G. Colombo 3, 35121 Padova, Italy.
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Cerni FA, Pucca MB, Amorim FG, de Castro Figueiredo Bordon K, Echterbille J, Quinton L, De Pauw E, Peigneur S, Tytgat J, Arantes EC. Isolation and characterization of Ts19 Fragment II, a new long-chain potassium channel toxin from Tityus serrulatus venom. Peptides 2016; 80:9-17. [PMID: 26116782 DOI: 10.1016/j.peptides.2015.06.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 06/05/2015] [Accepted: 06/08/2015] [Indexed: 01/13/2023]
Abstract
Ts19 Fragment II (Ts19 Frag-II) was first isolated from the venom of the scorpion Tityus serrulatus (Ts). It is a protein presenting 49 amino acid residues, three disulfide bridges, Mr 5534Da and was classified as a new member of class (subfamily) 2 of the β-KTxs, the second one described for Ts scorpion. The β-KTx family is composed by two-domain peptides: N-terminal helical domain (NHD), with cytolytic activity, and a C-terminal CSαβ domain (CCD), with Kv blocking activity. The extensive electrophysiological screening (16 Kv channels and 5 Nav channels) showed that Ts19 Frag-II presents a specific and significant blocking effect on Kv1.2 (IC50 value of 544±32nM). However, no cytolytic activity was observed with this toxin. We conclude that the absence of 9 amino acid residues from the N-terminal sequence (compared to Ts19 Frag-I) is responsible for the absence of cytolytic activity. In order to prove this hypothesis, we synthesized the peptide with these 9 amino acid residues, called Ts19 Frag-III. As expected, Ts19 Frag-III showed to be cytolytic and did not block the Kv1.2 channel. The post-translational modifications of Ts19 and its fragments (I-III) are also discussed here. A mechanism of post-translational processing (post-splitting) is suggested to explain Ts19 fragments production. In addition to the discovery of this new toxin, this report provides further evidence for the existence of several compounds in the scorpion venom contributing to the diversity of the venom arsenal.
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Affiliation(s)
- Felipe Augusto Cerni
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, 14040-903 Ribeirão Preto, SP, Brazil
| | - Manuela Berto Pucca
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, 14040-903 Ribeirão Preto, SP, Brazil
| | - Fernanda Gobbi Amorim
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, 14040-903 Ribeirão Preto, SP, Brazil
| | - Karla de Castro Figueiredo Bordon
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, 14040-903 Ribeirão Preto, SP, Brazil
| | - Julien Echterbille
- Laboratory of Mass Spectrometry, Department of Chemistry, University of Liège, Allée de la chimie 6, B6c, B-4000 Liège, Belgium
| | - Loïc Quinton
- Laboratory of Mass Spectrometry, Department of Chemistry, University of Liège, Allée de la chimie 6, B6c, B-4000 Liège, Belgium
| | - Edwin De Pauw
- Laboratory of Mass Spectrometry, Department of Chemistry, University of Liège, Allée de la chimie 6, B6c, B-4000 Liège, Belgium
| | - Steve Peigneur
- Toxicology and Pharmacology, University of Leuven, O&N 2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium
| | - Jan Tytgat
- Toxicology and Pharmacology, University of Leuven, O&N 2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium
| | - Eliane Candiani Arantes
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, 14040-903 Ribeirão Preto, SP, Brazil.
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Ye F, Hu Y, Yu W, Xie Z, Hu J, Cao Z, Li W, Wu Y. The Scorpion Toxin Analogue BmKTX-D33H as a Potential Kv1.3 Channel-Selective Immunomodulator for Autoimmune Diseases. Toxins (Basel) 2016; 8:115. [PMID: 27104568 PMCID: PMC4848641 DOI: 10.3390/toxins8040115] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 04/11/2016] [Accepted: 04/12/2016] [Indexed: 01/23/2023] Open
Abstract
The Kv1.3 channel-acting scorpion toxins usually adopt the conserved anti-parallel β-sheet domain as the binding interface, but it remains challenging to discover some highly selective Kv1.3 channel-acting toxins. In this work, we investigated the pharmacological profile of the Kv1.3 channel-acting BmKTX-D33H, a structural analogue of the BmKTX scorpion toxin. Interestingly, BmKTX-D33H, with its conserved anti-parallel β-sheet domain as a Kv1.3 channel-interacting interface, exhibited more than 1000-fold selectivity towards the Kv1.3 channel as compared to other K+ channels (including Kv1.1, Kv1.2, Kv1.7, Kv11.1, KCa2.2, KCa2.3, and KCa3.1). As expected, BmKTX-D33H was found to inhibit the cytokine production and proliferation of both Jurkat cells and human T cells in vitro. It also significantly improved the delayed-type hypersensitivity (DTH) responses, an autoreactive T cell-mediated inflammation in rats. Amino acid sequence alignment and structural analysis strongly suggest that the “evolutionary” Gly11 residue of BmKTX-D33H interacts with the turret domain of Kv1 channels; it appears to be a pivotal amino acid residue with regard to the selectivity of BmKTX-D33H towards the Kv1.3 channel (in comparison with the highly homologous scorpion toxins). Together, our data indicate that BmKTX-D33H is a Kv1.3 channel–specific blocker. Finally, the remarkable selectivity of BmKTX-D33H highlights the great potential of evolutionary-guided peptide drug design in future studies.
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Affiliation(s)
- Fang Ye
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Youtian Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Weiwei Yu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Zili Xie
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Jun Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
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Wang X, Gao B, Zhu S. A single-point mutation enhances dual functionality of a scorpion toxin. Comp Biochem Physiol C Toxicol Pharmacol 2016; 179:72-8. [PMID: 26358403 DOI: 10.1016/j.cbpc.2015.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 08/24/2015] [Accepted: 09/01/2015] [Indexed: 12/11/2022]
Abstract
Scorpion venom represents a tremendous, hitherto partially explored peptide library that has been proven to be useful not only for understanding ion channels but also for drug design. MeuTXKα3 is a functionally unknown scorpion toxin-like peptide. Here we describe new transcripts of this gene arising from alternative polyadenylation and its biological function as well as a mutant with a single-point substitution at site 30. Native-like MeuTXKα3 and its mutant were produced in Escherichia coli and their toxic function against Drosophila Shaker K(+) channel and its mammalian counterparts (rKv1.1-rKv1.3) were assayed by two-electrode voltage clamp technique. The results show that MeuTXKα3 is a weak toxin with a wide-spectrum of activity on both Drosophila and mammalian K(+) channels. The substitution of a proline at site 30 by an asparagine, an evolutionarily conserved functional residue in the scorpion α-KTx family, led to an increased activity on rKv1.2 and rKv1.3 but a decreased activity on the Shaker channel without changing the potency on rKv1.1, suggesting a key role of this site in species selectivity of scorpion toxins. MeuTXKα3 was also active on a variety of bacteria with lethal concentrations ranging from 4.66 to 52.01μM and the mutant even had stronger activity on some of these bacterial species. To the best of our knowledge, this is the first report on a bi-functional short-chain peptide in the lesser Asian scorpion venom. Further extensive mutations of MeuTXKα3 at site 30 could help improve its K(+) channel-blocking and antibacterial functions.
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Affiliation(s)
- Xueli Wang
- Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects & Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, 100101 Beijing, China
| | - Bin Gao
- Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects & Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, 100101 Beijing, China
| | - Shunyi Zhu
- Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects & Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, 100101 Beijing, China.
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Matsukawa J, Inatomi N, Otake K. [Pharmacological and clinical profiles of a novel potassium-competitive acid blocker, vonoprazan fumarate (Takecab(®) 10 mg and 20 mg)]. Nihon Yakurigaku Zasshi 2015; 146:275-282. [PMID: 26558313 DOI: 10.1254/fpj.146.275] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
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Abstract
There is a wide variety of ion channel types with various types of blockers, making research in this field very complicated. To reduce this complexity, it is essential to study ion channels and their blockers independently. Scorpion toxins, a major class of blockers, are charged short peptides with high affinities for potassium channels. Their high selectivity and inhibitory properties make them an important pharmacological tool for treating autoimmune or nervous system disorders. Scorpion toxins typically have highly charged surfaces and-like other proteins-an intrinsic ability to bind ions (Friedman J Phys Chem B 115(29):9213-9223, 1996; Baldwin Biophys J 71(4):2056-2063, 1996; Vrbka et al. Proc Natl Acad Sci USA 103(42):15440-15444, 2006a; Vrbka et al. J Phys Chem B 110(13):7036-43, 2006b). Thus, their effects on potassium channels are usually investigated in various ionic solutions. In this work, computer simulations of protein structures were performed to analyze the structural properties of the key residues (i.e., those that are presumably involved in contact with the surfaces of the ion channels) of 12 scorpion toxins. The presence of the two most physiologically abundant cations, Na(+) and K(+), was considered. The results indicated that the ion-binding properties of the toxin residues vary. Overall, all of the investigated toxins had more stable structures in ionic solutions than in water. We found that both the number and length of elements in the secondary structure varied depending on the ionic solution used (i.e., in the presence of NaCl or KCl). This study revealed that the ionic solution should be chosen carefully before performing experiments on these toxins. Similarly, the influence of these ions should be taken into consideration in the design of toxin-based pharmaceuticals.
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Affiliation(s)
- Azadeh Nikouee
- Institute of Applied Physiology, Ulm University, Ulm, Germany
| | - Morteza Khabiri
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610, Prague 6, Czech Republic.
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Lukasz Cwiklik
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610, Prague 6, Czech Republic
- J. Heyrovský Institute of Physical Chemistry Academy of Sciences of the Czech Republic v.v.i., Dolejskova 3, 18223, Prague 8, Czech Republic
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Hu Y, Chen J, Wang B, Yang W, Zhang C, Hu J, Xie Z, Cao Z, Li W, Wu Y, Chen Z. Engineering a peptide inhibitor towards the KCNQ1/KCNE1 potassium channel (IKs). Peptides 2015; 71:77-83. [PMID: 26188173 DOI: 10.1016/j.peptides.2015.07.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 07/05/2015] [Accepted: 07/07/2015] [Indexed: 11/27/2022]
Abstract
The KCNQ1/KCNE1 channel (IKs) plays important roles in the physiological and pathological process of heart, but no potent peptide acting on this channel has been reported. In this work, we found that the natural scorpion venom hardly inhibited KCNQ1/KCNE1 channel currents. Based on this observation, we attempted to use three natural scorpion toxins ChTX, BmKTX and OmTx2 with two different structural folds as templates to engineer potent peptide inhibitors towards the KCNQ1/KCNE1 channel. Pharmacological experiments showed that when we screen with 1μM MT2 peptide, an analog derived from BmKTX toxin, KCNQ1/KCNE1 channel currents could be effectively inhibited. Concentration-dependent experiments showed that MT2 inhibited the KCNQ1/KCNE1 channel with an IC50 value of 4.6±1.9μM. The mutagenesis experiments indicated that MT2 peptide likely used Lys26 residue to interact with the KCNQ1/KCNE1 channel. With MT2 as a new template, we further designed a more potent MT2-2 peptide, which selectively inhibited the KCNQ1/KCNE1 channel with an IC50 of 1.51±0.62μM. Together, this work provided a much potent KCNQ1/KCNE1 channel peptide inhibitor so far, and highlighted the role of molecular strategy in developing potent peptide inhibitors for the natural toxin-insensitive orphan receptors.
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Affiliation(s)
- Youtian Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jing Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Bin Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Weishan Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Chuangeng Zhang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jun Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Zili Xie
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China; Center for BioDrug Research, Wuhan University, Wuhan 430072, China
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China; Center for BioDrug Research, Wuhan University, Wuhan 430072, China
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China; Center for BioDrug Research, Wuhan University, Wuhan 430072, China.
| | - Zongyun Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China; Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Hubei University of Medicine, Hubei, China.
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50
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Du K, De Mieri M, Saxena P, Phungula KV, Wilhelm A, Hrubaru MM, van Rensburg E, Zietsman PC, Hering S, van der Westhuizen JH, Hamburger M. HPLC-Based Activity Profiling for hERG Channel Inhibitors in the South African Medicinal Plant Galenia africana. Planta Med 2015; 81:1154-1162. [PMID: 25922911 DOI: 10.1055/s-0035-1545929] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The human ether-a-go-go-related gene channel is a voltage-activated K(+) channel involved in cardiac action potential. Its inhibition can lead to QT prolongation, and eventually to potentially fatal arrhythmia. Therefore, it is considered a primary antitarget in safety pharmacology. To assess the risk of human ether-a-go-go-related gene channel inhibition by medicinal plants, 700 extracts from different parts of 142 medicinal plants collected in Southern Africa were screened on Xenopus laevis oocytes. A CH2Cl2 extract from the stems and leaves of Galenia africana (Aizoaceae) reduced the peak tail human ether-a-go-go-related gene current by 50.4 ± 5.5 % (n = 3) at a concentration of 100 µg/mL. By means of high-performance liquid chromatography-based activity profiling, nine flavonoids were identified in the active time windows. However, the human ether-a-go-go-related gene channel inhibition of isolated compounds was less pronounced than that of extract and active microfractions (human ether-a-go-go-related gene inhibition between 10.1 ± 5 and 14.1 ± 1.6 at 100 µM). The two major constituents, 7,8-methylenedioxyflavone (1) and 7,8-dimethoxyflavone (13), were quantified (4.3 % and 9.4 %, respectively, in the extract). Further human ether-a-go-go-related gene inhibition tests for compounds 1 and 13 at 300 µM showed a concentration-dependent inhibitory activity (33.2 ± 12.4 and 30.0 ± 7.4, respectively). In a detailed phytochemical profiling of the active extract, a total of 20 phenolic compounds, including six new natural products, were isolated and identified.
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Affiliation(s)
- Kun Du
- Department of Chemistry, University of the Free State, Bloemfontein, South Africa
| | - Maria De Mieri
- Division of Pharmaceutical Biology, University of Basel, Basel, Switzerland
| | - Priyanka Saxena
- Institute of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Khanya V Phungula
- Department of Chemistry, University of the Free State, Bloemfontein, South Africa
| | - Anke Wilhelm
- Department of Chemistry, University of the Free State, Bloemfontein, South Africa
| | | | | | | | - Steffen Hering
- Institute of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | | | - Matthias Hamburger
- Division of Pharmaceutical Biology, University of Basel, Basel, Switzerland
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