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https://www.readbyqxmd.com/read/28992755/drug-mediated-shortening-of-action-potentials-in-lqts2-human-induced-pluripotent-stem-cell-derived-cardiomyocytes
#1
Gary Duncan, Karl Firth, Vinoj George, Minh Duc Hoang, Andrew Staniforth, Godfrey Smith, Chris Denning
Cardiomyocytes (CMs) derived from human induced pluripotent stem cells (hiPSCs) are now a well-established modality for modelling genetic disorders of the heart. This is especially so for long QT syndrome (LQTS), which is caused by perturbation of ion channel function, and can lead to fainting, malignant arrhythmias and sudden cardiac death. LQTS2 is caused by mutations in KCNH2, a gene whose protein product contributes to IKr (also known as HERG), which is the predominant repolarising potassium current in CMs...
October 9, 2017: Stem Cells and Development
https://www.readbyqxmd.com/read/28986934/mechanistic-model-informed-proarrhythmic-risk-assessment-of-drugs-review-of-the-cipa-initiative-and-design-of-a-prospective-clinical-validation-study
#2
Jose Vicente, Robbert Zusterzeel, Lars Johannesen, Jay Mason, Philip Sager, Vikram Patel, Murali K Matta, Zhihua Li, Jiang Liu, Christine Garnett, Norman Stockbridge, Issam Zineh, David G Strauss
The Comprehensive in vitro Proarrhythmia Assay (CiPA) initiative is developing and validating a mechanistic-based assessment of proarrhythmic risk of drugs. CiPA proposes to assess a drug's effect on multiple ion channels and integrate the effects in a computer model of the human cardiomyocyte to predict proarrhythmic risk. Unanticipated or missed effects will be assessed with human stem cell derived cardiomyocytes and electrocardiogram (ECG) analysis in early phase 1 clinical trials. This paper provides an overview of CiPA and the rationale and design of the CiPA phase 1 ECG validation clinical trial, which involves assessing an additional ECG biomarker (J-Tpeak) for QT prolonging drugs...
October 7, 2017: Clinical Pharmacology and Therapeutics
https://www.readbyqxmd.com/read/28957753/structure-based-design-of-herg-neutral-antihypertensive-oxazalone-and-imidazolone-derivatives
#3
Busecan Aksoydan, Isik Kantarcioglu, Ismail Erol, Ramin Ekhteiari Salmas, Serdar Durdagi
Angiotensin II receptor type 1 (AT1) antagonists are the most recent drug class against hypertension. Recently first crystal structure of AT1 receptor is deposited to the protein data bank (PDB ID: 4YAY). In this work, several molecular screening methods such as molecular docking and de novo design studies were performed and it is found that oxazolone and imidazolone derivatives reveal similar/better interaction energy profiles compared to the FDA approved sartan molecules at the binding site of the AT1 receptor...
August 12, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28939972/effects-of-benzothiazolamines-on-voltage-gated-sodium-channels
#4
Alessandro Farinato, Concetta Altamura, Jean-François Desaphy
Benzothiazole is a versatile fused heterocycle that aroused much interest in drug discovery as anticonvulsant, neuroprotective, analgesic, anti-inflammatory, antimicrobial, and anticancer. Two benzothiazolamines, riluzole and lubeluzole, are known blockers of voltage-gated sodium (Nav) channels. Riluzole is clinically used as a neuroprotectant in amyotrophic lateral sclerosis. Inhibition of Nav channels by riluzole is voltage-dependent due to preferential binding to inactivated sodium channels. Yet the drug exerts little use-dependent block, probably because it lacks protonable amine...
September 23, 2017: Handbook of Experimental Pharmacology
https://www.readbyqxmd.com/read/28928044/electrocardiographic-biomarkers-to-confirm-drug-s-electrophysiological-effects-used-for-proarrhythmic-risk-prediction-under-cipa
#5
Jose Vicente, Meisam Hosseini, Lars Johannesen, David G Strauss
The ECG plays a critical role in the thorough QT study. This clinical study is part of the assessment of proarrhythmic potential of drugs under the current regulatory paradigm. While the current paradigm has been successful in preventing drugs with unexpected QT prolongation or torsade risk from reaching the market, the focus on QT prolongation has likely resulted in potentially beneficial compounds with minimal torsade risk being dropped from development. The Comprehensive in vitro Proarrhythmia Assay (CiPA) initiative is developing and validating a new mechanistic-based paradigm for cardiac safety evaluation of drugs...
August 9, 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/28927796/development-and-evaluation-of-4-pyrrolidin-3-yl-benzonitrile-derivatives-as-inhibitors-of-lysine-specific-demethylase-1
#6
Daniel P Mould, Ulf Bremberg, Allan M Jordan, Matthis Geitmann, Alison E McGonagle, Tim C P Somervaille, Gary J Spencer, Donald J Ogilvie
As part of our ongoing efforts to develop reversible inhibitors of LSD1, we identified a series of 4-(pyrrolidin-3-yl)benzonitrile derivatives that act as successful scaffold-hops of the literature inhibitor GSK-690. The most active compound, 21g, demonstrated a Kd value of 22nM and a biochemical IC50 of 57nM. In addition, this compound displayed improved selectivity over the hERG ion channel compared to GSK-690, and no activity against the related enzymes MAO-A and B. In human THP-1 acute myeloid leukaemia cells, 21g was found to increase the expression of the surrogate cellular biomarker CD86...
August 24, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28902151/apetx4-a-novel-sea-anemone-toxin-and-a-modulator-of-the-cancer-relevant-potassium-channel-kv10-1
#7
Lien Moreels, Steve Peigneur, Diogo T Galan, Edwin De Pauw, Lászlo Béress, Etienne Waelkens, Luis A Pardo, Loïc Quinton, Jan Tytgat
The human ether-à-go-go channel (hEag1 or KV10.1) is a cancer-relevant voltage-gated potassium channel that is overexpressed in a majority of human tumors. Peptides that are able to selectively inhibit this channel can be lead compounds in the search for new anticancer drugs. Here, we report the activity-guided purification and electrophysiological characterization of a novel KV10.1 inhibitor from the sea anemone Anthopleura elegantissima. Purified sea anemone fractions were screened for inhibitory activity on KV10...
September 13, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28861002/analysis-of-24-h-rhythm-in-ventricular-repolarization-identifies-qt-diurnality-as-a-novel-clinical-parameter-associated-with-previous-ventricular-arrhythmias-in-heart-failure-patients
#8
Bastiaan C Du Pre, Linda W Van Laake, Matthias Meine, Jeroen F Van der Heijden, Pieter A Doevendans, Marc A Vos, Toon A B Van Veen
Introduction: Cardiac repolarization abnormalities are among the major causes of ventricular arrhythmias and sudden cardiac death. In humans, cardiac repolarization duration has a 24-h rhythm. Animal studies show that this rhythm is regulated by 24-h rhythms in ion channel function and that disruption of this rhythm leads to ventricular arrhythmias. We hypothesized that 24-h rhythms in QT duration can be used as a predictor for sudden cardiac death and are associated with ventricular arrhythmias. Secondly, we assessed a possible mechanistic explanation by studying the putative role of hERG channel dysfunction...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28851973/frequency-dependent-drug-screening-using-optogenetic-stimulation-of-human-ipsc-derived-cardiomyocytes
#9
Hendrik Lapp, Tobias Bruegmann, Daniela Malan, Stephanie Friedrichs, Carsten Kilgus, Alexandra Heidsieck, Philipp Sasse
Side effects on cardiac ion channels are one major reason for new drugs to fail during preclinical evaluation. Herein we propose a simple optogenetic screening tool measuring extracellular field potentials (FP) from paced cardiomyocytes to identify drug effects over the whole physiological heart range, which is essential given the rate-dependency of ion channel function and drug action. Human induced pluripotent stem cell-derived cardiomyocytes were transduced with an adeno-associated virus to express Channelrhodopsin2 and plated on micro-electrode arrays...
August 29, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28830713/characterization-of-loperamide-mediated-block-of-herg-channels-at-physiological-temperature-and-its-proarrhythmia-propensity
#10
Jiansong Sheng, Phu N Tran, Zhihua Li, Sara Dutta, Kelly Chang, Thomas Colatsky, Wendy W Wu
BACKGROUND: Loperamide (Immodium®) is indicated for symptomatic control of diarrhea. It is a μ-opioid receptor agonist, and recently has been associated with misuse and abuse. At therapeutic doses loperamide has not been associated with cardiotoxicity. However, loperamide overdose is associated with proarrhythmia and death - two effects that are likely attributable to its block of cardiac ion channels that are critical for generating action potentials. In this study, we defined loperamide-hERG channel interaction characteristics, and used a ventricular myocyte action potential model to compare loperamide's proarrhythmia propensity to twelve drugs with defined levels of clinical risk...
August 19, 2017: Journal of Pharmacological and Toxicological Methods
https://www.readbyqxmd.com/read/28756335/computational-approaches-to-understand-the-adverse-drug-effect-on-potassium-sodium-and-calcium-channels-for-predicting-tdp-cardiac-arrhythmias
#11
Mohsen Sharifi
Ion channels play a crucial role in the cardiovascular system. Our understanding of cardiac ion channel function has improved since their first discoveries. The flow of potassium, sodium and calcium ions across cardiomyocytes is vital for regular cardiac rhythm. Blockage of these channels, delays cardiac repolarization or tend to shorten repolarization and may induce arrhythmia. Detection of drug risk by channel blockade is considered essential for drug regulators. Advanced computational models can be used as an early screen for torsadogenic potential in drug candidates...
July 8, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28748465/automated-patch-clamp-methods-for-the-herg-cardiac-potassium-channel
#12
Sylvie Houtmann, Brigitte Schombert, Camille Sanson, Michel Partiseti, G Andrees Bohme
The human Ether-a-go-go Related Gene (hERG) product has been identified as a central ion channel underlying both familial forms of elongated QT interval on the electrocardiogram and drug-induced elongation of the same QT segment. Indeed, reduced function of this potassium channel involved in the repolarization of the cardiac action potential can produce a type of life-threatening cardiac ventricular arrhythmias called Torsades de Pointes (TdP). Therefore, hERG inhibitory activity of newly synthetized molecules is a relevant structure-activity metric for compound prioritization and optimization in medicinal chemistry phases of drug discovery...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28741726/ns1643-enhances-ionic-currents-in-a-g604s-wt-herg-co-expression-system-associated-with-long-qt-syndrome-2
#13
JianHua Huo, Xueyan Guo, Qun Lu, Hua Qiang, Ping Liu, Ling Bai, Christopher Lh Huang, Yanmin Zhang, Aiqun Ma
Loss of function mutations in the human ether-a-go-go-related gene (hERG) cause long QT syndrome type 2 (LQT2). Most LQT2 patients are heterozygous mutation carriers in which the mutant hERG exerts potent dominant-negative effects. 1, 3-bis-(2-hydroxy-5-trifluoromethyl-phenyl)-urea (NS1643) is known to enhance IKr in WT-hERG. We investigated its actions following lipofectamine-induced expression of both mutant G604S- and WT-hERG in the heterologous HEK293 expression system. Cells transfected with pcDNA3-G604S-hERG did not lead to any expression of detectable currents whether before or following NS1643 challenge...
July 25, 2017: Clinical and Experimental Pharmacology & Physiology
https://www.readbyqxmd.com/read/28681507/correlation-between-human-ether-a-go-go-related-gene-channel-inhibition-and-action-potential-prolongation
#14
P Saxena, M P Hortigon-Vinagre, S Beyl, I Baburin, S Andranovits, S M Iqbal, A Costa, A P IJzerman, P Kügler, E Timin, G L Smith, S Hering
BACKGROUND AND PURPOSE: Human ether-a-go-go-related gene (hERG; Kv 11.1) channel inhibition is a widely accepted predictor of cardiac arrhythmia. hERG channel inhibition alone is often insufficient to predict pro-arrhythmic drug effects. This study used a library of dofetilide derivatives to investigate the relationship between standard measures of hERG current block in an expression system and changes in action potential duration (APD) in human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs)...
September 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/28552773/voltage-gated-ion-channels-blockade-is-the-underlying-mechanism-of-bimu8-induced-cardiotoxicity
#15
Shahid Muhammad Iqbal, Rosa Lemmens-Gruber
BIMU8 is a 5-HT4a receptor agonist and used as an experimental drug to counteract opioid induced respiratory depression. In preliminary experiments serious disturbances in ECG were observed in anesthetized rabbits which prompted us to explore the underlying cause of BIMU8 induced abnormal changes in ECG recordings. Electrophysiological experiments were performed on HEK-293 cells expressing hERG, CaV1.2 and NaV1.5 ion channels. In whole-cell recordings BIMU8 effectively blocked these three channels, with IC50 values of 0...
August 5, 2017: Toxicology Letters
https://www.readbyqxmd.com/read/28551711/why-are-most-phospholipidosis-inducers-also-herg-blockers
#16
Svetoslav Slavov, Iva Stoyanova-Slavova, Shuaizhang Li, Jinghua Zhao, Ruili Huang, Menghang Xia, Richard Beger
Recent reports have noted that a number of compounds that block the human Ether-à-go-go related gene (hERG) ion channel also induce phospholipidosis (PLD). To explore a hypothesis explaining why most PLD inducers are also hERG inhibitors, a modeling approach was undertaken with data sets comprised of 4096 compounds assayed for hERG inhibition and 5490 compounds assayed for PLD induction. To eliminate the chemical domain effect, a filtered data set of 567 compounds tested in quantitative high-throughput screening (qHTS) format for both hERG inhibition and PLD induction was constructed...
May 27, 2017: Archives of Toxicology
https://www.readbyqxmd.com/read/28544109/express-with-caution-epitope-tags-and-cdna-variants-effects-on-herg-channel-trafficking-half-life-and-function
#17
Marika L Osterbur Badhey, Alexander C Bertalovitz, Thomas V McDonald
INTRODUCTION: Genetic mutations in KCNH2, which encodes hERG, the alpha subunit of the potassium channel responsible for the IKr current, cause long QT syndrome (LQTS), an inherited cardiac arrhythmia disorder. Electrophysiology techniques are used to correlate genotype with molecular phenotype to determine which mutations identified in patients diagnosed with LQTS are disease causing, and which are benign. These investigations are usually done using heterologous expression in cell lines, and often, epitope fusion tags are used to enable isolation and identification of the protein of interest...
May 24, 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/28542428/age-dependent-electrical-and-morphological-remodeling-of-the-drosophila-heart-caused-by-herg-seizure-mutations
#18
Karen Ocorr, Alexander Zambon, Yoav Nudell, Santiago Pineda, Soda Diop, Min Tang, Takeshi Akasaka, Erika Taylor
Understanding the cellular-molecular substrates of heart disease is key to the development of cardiac specific therapies and to the prevention of off-target effects by non-cardiac targeted drugs. One of the primary targets for therapeutic intervention has been the human ether a go-go (hERG) K+ channel that, together with the KCNQ channel, controls the rate and efficiency of repolarization in human myocardial cells. Neither of these channels plays a major role in adult mouse heart function; however, we show here that the hERG homolog seizure (sei), along with KCNQ, both contribute significantly to adult heart function as they do in humans...
May 2017: PLoS Genetics
https://www.readbyqxmd.com/read/28532668/design-synthesis-and-biological-evaluation-of-4-piperazinyl-containing-chidamide-derivatives-as-hdacs-inhibitors
#19
Qingwei Zhang, Bingliu Lu, Jianqi Li
The synthesis and biological evaluation of a variety of 4-piperazinyl-containing Chidamide derivatives is described. Some of these compounds were shown to inhibit HDAC1 with IC50 values below micromolar range, and inhibited proliferation of several human cancer cells, not possessing toxicity to human normal cells and hERG K(+) ion channels. Compound 9g, proved to be the most potent and efficacious derivative in this series, was orally active in an HCT116 xenograft model in vivo.
July 15, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28497823/natural-products-modulating-the-herg-channel-heartaches-and-hope
#20
REVIEW
Jadel M Kratz, Ulrike Grienke, Olaf Scheel, Stefan A Mann, Judith M Rollinger
Covering: 1996-December 2016The human Ether-à-go-go Related Gene (hERG) channel is a voltage-gated potassium channel playing an essential role in the normal electrical activity in the heart. It is involved in the repolarization and termination of action potentials in excitable cardiac cells. Mutations in the hERG gene and hERG channel blockage by small molecules are associated with increased risk of fatal arrhythmias. Several drugs have been withdrawn from the market due to hERG channel-related cardiotoxicity...
August 2, 2017: Natural Product Reports
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