1
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Ku T, Cao J, Won SJ, Guo J, Camacho-Hernandez GA, Okorom AV, Salomon KW, Lee KH, Loland CJ, Duff HJ, Shi L, Newman AH. Series of (([1,1'-Biphenyl]-2-yl)methyl)sulfinylalkyl Alicyclic Amines as Novel and High Affinity Atypical Dopamine Transporter Inhibitors with Reduced hERG Activity. ACS Pharmacol Transl Sci 2024; 7:515-532. [PMID: 38357284 PMCID: PMC10863442 DOI: 10.1021/acsptsci.3c00322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/15/2023] [Accepted: 12/22/2023] [Indexed: 02/16/2024]
Abstract
Currently, there are no FDA-approved medications for the treatment of psychostimulant use disorders (PSUD). We have previously discovered "atypical" dopamine transporter (DAT) inhibitors that do not display psychostimulant-like behaviors and may be useful as medications to treat PSUD. Lead candidates (e.g., JJC8-091, 1) have shown promising in vivo profiles in rodents; however, reducing hERG (human ether-à-go-go-related gene) activity, a predictor of cardiotoxicity, has remained a challenge. Herein, a series of 30 (([1,1'-biphenyl]-2-yl)methyl)sulfinylalkyl alicyclic amines was synthesized and evaluated for DAT and serotonin transporter (SERT) binding affinities. A subset of analogues was tested for hERG activity, and the IC50 values were compared to those predicted by our hERG QSAR models, which showed robust predictive power. Multiparameter optimization scores (MPO > 3) indicated central nervous system (CNS) penetrability. Finally, comparison of affinities in human DAT and its Y156F and Y335A mutants suggested that several compounds prefer an inward facing conformation indicating an atypical DAT inhibitor profile.
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Affiliation(s)
- Therese
C. Ku
- Molecular
Targets and Medications Discovery Branch, National Institute on Drug
Abuse–Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Jianjing Cao
- Molecular
Targets and Medications Discovery Branch, National Institute on Drug
Abuse–Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Sung Joon Won
- Molecular
Targets and Medications Discovery Branch, National Institute on Drug
Abuse–Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Jiqing Guo
- Faculty
of Medicine, Libin Institute, Calgary T2N 4N1, Canada
| | - Gisela A. Camacho-Hernandez
- Molecular
Targets and Medications Discovery Branch, National Institute on Drug
Abuse–Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Amarachi V. Okorom
- Molecular
Targets and Medications Discovery Branch, National Institute on Drug
Abuse–Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Kristine Walloe Salomon
- Laboratory
for Membrane Protein Dynamics, Department of Neuroscience, Faculty
of Health and Medical Sciences, University
of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Kuo Hao Lee
- Molecular
Targets and Medications Discovery Branch, National Institute on Drug
Abuse–Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Claus J. Loland
- Laboratory
for Membrane Protein Dynamics, Department of Neuroscience, Faculty
of Health and Medical Sciences, University
of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Henry J. Duff
- Laboratory
for Membrane Protein Dynamics, Department of Neuroscience, Faculty
of Health and Medical Sciences, University
of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Lei Shi
- Molecular
Targets and Medications Discovery Branch, National Institute on Drug
Abuse–Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Amy Hauck Newman
- Molecular
Targets and Medications Discovery Branch, National Institute on Drug
Abuse–Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
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2
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Janz A, Walz K, Cirnu A, Surjanto J, Urlaub D, Leskien M, Kohlhaas M, Nickel A, Brand T, Nose N, Wörsdörfer P, Wagner N, Higuchi T, Maack C, Dudek J, Lorenz K, Klopocki E, Ergün S, Duff HJ, Gerull B. Mutations in DNAJC19 cause altered mitochondrial structure and increased mitochondrial respiration in human iPSC-derived cardiomyocytes. Mol Metab 2024; 79:101859. [PMID: 38142971 PMCID: PMC10792641 DOI: 10.1016/j.molmet.2023.101859] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 12/06/2023] [Accepted: 12/20/2023] [Indexed: 12/26/2023] Open
Abstract
BACKGROUND Dilated cardiomyopathy with ataxia (DCMA) is an autosomal recessive disorder arising from truncating mutations in DNAJC19, which encodes an inner mitochondrial membrane protein. Clinical features include an early onset, often life-threatening, cardiomyopathy associated with other metabolic features. Here, we aim to understand the metabolic and pathophysiological mechanisms of mutant DNAJC19 for the development of cardiomyopathy. METHODS We generated induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) of two affected siblings with DCMA and a gene-edited truncation variant (tv) of DNAJC19 which all lack the conserved DnaJ interaction domain. The mutant iPSC-CMs and their respective control cells were subjected to various analyses, including assessments of morphology, metabolic function, and physiological consequences such as Ca2+ kinetics, contractility, and arrhythmic potential. Validation of respiration analysis was done in a gene-edited HeLa cell line (DNAJC19tvHeLa). RESULTS Structural analyses revealed mitochondrial fragmentation and abnormal cristae formation associated with an overall reduced mitochondrial protein expression in mutant iPSC-CMs. Morphological alterations were associated with higher oxygen consumption rates (OCRs) in all three mutant iPSC-CMs, indicating higher electron transport chain activity to meet cellular ATP demands. Additionally, increased extracellular acidification rates suggested an increase in overall metabolic flux, while radioactive tracer uptake studies revealed decreased fatty acid uptake and utilization of glucose. Mutant iPSC-CMs also showed increased reactive oxygen species (ROS) and an elevated mitochondrial membrane potential. Increased mitochondrial respiration with pyruvate and malate as substrates was observed in mutant DNAJC19tv HeLa cells in addition to an upregulation of respiratory chain complexes, while cellular ATP-levels remain the same. Moreover, mitochondrial alterations were associated with increased beating frequencies, elevated diastolic Ca2+ concentrations, reduced sarcomere shortening and an increased beat-to-beat rate variability in mutant cell lines in response to β-adrenergic stimulation. CONCLUSIONS Loss of the DnaJ domain disturbs cardiac mitochondrial structure with abnormal cristae formation and leads to mitochondrial dysfunction, suggesting that DNAJC19 plays an essential role in mitochondrial morphogenesis and biogenesis. Moreover, increased mitochondrial respiration, altered substrate utilization, increased ROS production and abnormal Ca2+ kinetics provide insights into the pathogenesis of DCMA-related cardiomyopathy.
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Affiliation(s)
- Anna Janz
- Comprehensive Heart Failure Center, Department of Cardiovascular Genetics, University Hospital Würzburg, Würzburg, Germany
| | - Katharina Walz
- Comprehensive Heart Failure Center, Department of Cardiovascular Genetics, University Hospital Würzburg, Würzburg, Germany
| | - Alexandra Cirnu
- Comprehensive Heart Failure Center, Department of Cardiovascular Genetics, University Hospital Würzburg, Würzburg, Germany
| | - Jessica Surjanto
- Comprehensive Heart Failure Center, Department of Cardiovascular Genetics, University Hospital Würzburg, Würzburg, Germany
| | - Daniela Urlaub
- Comprehensive Heart Failure Center, Department of Cardiovascular Genetics, University Hospital Würzburg, Würzburg, Germany
| | - Miriam Leskien
- Comprehensive Heart Failure Center, Department of Cardiovascular Genetics, University Hospital Würzburg, Würzburg, Germany
| | - Michael Kohlhaas
- Comprehensive Heart Failure Center, Department of Translational Research, University Hospital Würzburg, Würzburg, Germany
| | - Alexander Nickel
- Comprehensive Heart Failure Center, Department of Translational Research, University Hospital Würzburg, Würzburg, Germany
| | - Theresa Brand
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - Naoko Nose
- Comprehensive Heart Failure Center, Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Philipp Wörsdörfer
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Nicole Wagner
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Takahiro Higuchi
- Comprehensive Heart Failure Center, Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Christoph Maack
- Comprehensive Heart Failure Center, Department of Translational Research, University Hospital Würzburg, Würzburg, Germany; Department of Medicine I, University Hospital Würzburg, Würzburg, Germany
| | - Jan Dudek
- Comprehensive Heart Failure Center, Department of Translational Research, University Hospital Würzburg, Würzburg, Germany
| | - Kristina Lorenz
- Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany; Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Dortmund, Germany
| | - Eva Klopocki
- Institute for Human Genetics, Biocenter, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Henry J Duff
- Department of Cardiac Sciences and Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Brenda Gerull
- Comprehensive Heart Failure Center, Department of Cardiovascular Genetics, University Hospital Würzburg, Würzburg, Germany; Department of Medicine I, University Hospital Würzburg, Würzburg, Germany; Department of Cardiac Sciences and Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada.
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3
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Kudaibergenova M, Guo J, Khan HM, Lees-Miller J, Mousaei M, Miranda W, Ngo VA, Noskov SY, Tieleman DP, Duff HJ. The voltage-sensing domain of a hERG1 mutant is a cation-selective channel. Biophys J 2022; 121:4585-4599. [PMID: 36815709 PMCID: PMC9748372 DOI: 10.1016/j.bpj.2022.10.032] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/29/2022] [Accepted: 10/24/2022] [Indexed: 11/24/2022] Open
Abstract
A cationic leak current known as an "omega current" may arise from mutations of the first charged residue in the S4 of the voltage sensor domains of sodium and potassium voltage-gated channels. The voltage-sensing domains (VSDs) in these mutated channels act as pores allowing nonspecific passage of cations, such as Li+, K+, Cs+, and guanidinium. Interestingly, no omega currents have been previously detected in the nonswapped voltage-gated potassium channels such as the human-ether-a-go-go-related (hERG1), hyperpolarization-activated cyclic nucleotide-gated, and ether-a-go-go channels. In this work, we discovered a novel omega current by mutating the first charged residue of the S4 of the hERG1, K525 to serine. To characterize this omega current, we used various probes, including the hERG1 pore domain blocker, dofetilide, to show that the omega current does not require cation flux via the canonical pore domain. In addition, the omega flux does not cross the conventional selectivity filter. We also show that the mutated channel (K525S hERG1) conducts guanidinium. These data are indicative of the formation of an omega current channel within the VSD. Using molecular dynamics simulations with replica-exchange umbrella sampling simulations of the wild-type hERG1 and the K525S hERG1, we explored the molecular underpinnings governing the cation flow in the VSD of the mutant. We also show that the wild-type hERG1 may form water crevices supported by the biophysical surface accessibility data. Overall, our multidisciplinary study demonstrates that the VSD of hERG1 may act as a cation-selective channel wherein a mutation of the first charged residue in the S4 generates an omega current. Our simulation uncovers the atomistic underpinning of this mechanism.
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Affiliation(s)
- Meruyert Kudaibergenova
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Jiqing Guo
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Hanif M Khan
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - James Lees-Miller
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Mahdi Mousaei
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Williams Miranda
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Van A Ngo
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Sergei Yu Noskov
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, AB, Canada.
| | - Henry J Duff
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada.
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4
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Gillis AM, Duff HJ, Mitchell LB. D. George Wyse, MD, PhD, FRCPC, FHRS (1941–2022). Heart Rhythm 2022. [DOI: 10.1016/j.hrthm.2022.01.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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5
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Lee KH, Fant AD, Guo J, Guan A, Jung J, Kudaibergenova M, Miranda WE, Ku T, Cao J, Wacker S, Duff HJ, Newman AH, Noskov SY, Shi L. Toward Reducing hERG Affinities for DAT Inhibitors with a Combined Machine Learning and Molecular Modeling Approach. J Chem Inf Model 2021; 61:4266-4279. [PMID: 34420294 DOI: 10.1021/acs.jcim.1c00856] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Psychostimulant drugs, such as cocaine, inhibit dopamine reuptake via blockading the dopamine transporter (DAT), which is the primary mechanism underpinning their abuse. Atypical DAT inhibitors are dissimilar to cocaine and can block cocaine- or methamphetamine-induced behaviors, supporting their development as part of a treatment regimen for psychostimulant use disorders. When developing these atypical DAT inhibitors as medications, it is necessary to avoid off-target binding that can produce unwanted side effects or toxicities. In particular, the blockade of a potassium channel, human ether-a-go-go (hERG), can lead to potentially lethal ventricular tachycardia. In this study, we established a counter screening platform for DAT and against hERG binding by combining machine learning-based quantitative structure-activity relationship (QSAR) modeling, experimental validation, and molecular modeling and simulations. Our results show that the available data are adequate to establish robust QSAR models, as validated by chemical synthesis and pharmacological evaluation of a validation set of DAT inhibitors. Furthermore, the QSAR models based on subsets of the data according to experimental approaches used have predictive power as well, which opens the door to target specific functional states of a protein. Complementarily, our molecular modeling and simulations identified the structural elements responsible for a pair of DAT inhibitors having opposite binding affinity trends at DAT and hERG, which can be leveraged for rational optimization of lead atypical DAT inhibitors with desired pharmacological properties.
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Affiliation(s)
- Kuo Hao Lee
- Computational Chemistry and Molecular Biophysics Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Andrew D Fant
- Computational Chemistry and Molecular Biophysics Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Jiqing Guo
- Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Andy Guan
- Computational Chemistry and Molecular Biophysics Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Joslyn Jung
- Computational Chemistry and Molecular Biophysics Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Mary Kudaibergenova
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Williams E Miranda
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Therese Ku
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Jianjing Cao
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Soren Wacker
- Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada.,Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada.,Achlys Inc., 7-126 Li Ka Shing Center for Health and Innovation, Edmonton, Alberta T6G 2E1, Canada
| | - Henry J Duff
- Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Amy Hauck Newman
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Sergei Y Noskov
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, United States
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6
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Cheung CC, Davies B, Roberts JD, Tadros R, Green MS, Healey JS, Simpson CS, Sanatani S, Steinberg C, Gardner MJ, MacIntyre C, Angaran P, Duff HJ, Talajic M, Hamilton RM, Arbour L, Leather RA, Seifer CM, Anne Fournier, Joza JE, Klein GJ, Laksman Z, Krahn AD. B-PO01-020 MACHINE LEARNING TO PREDICT RECURRENT EVENTS FOLLOWING UNEXPLAINED CARDIAC ARREST. Heart Rhythm 2021. [DOI: 10.1016/j.hrthm.2021.06.166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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7
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Miranda WE, Guo J, Mesa-Galloso H, Corradi V, Lees-Miller JP, Tieleman DP, Duff HJ, Noskov SY. Lipid regulation of hERG1 channel function. Nat Commun 2021; 12:1409. [PMID: 33658490 PMCID: PMC7930123 DOI: 10.1038/s41467-021-21681-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [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: 06/04/2020] [Accepted: 01/29/2021] [Indexed: 01/31/2023] Open
Abstract
The lipid regulation of mammalian ion channel function has emerged as a fundamental mechanism in the control of electrical signalling and transport specificity in various cell types. In this work, we combine molecular dynamics simulations, mutagenesis, and electrophysiology to provide mechanistic insights into how lipophilic molecules (ceramide-sphingolipid probe) alter gating kinetics and K+ currents of hERG1. We show that the sphingolipid probe induced a significant left shift of activation voltage, faster deactivation rates, and current blockade comparable to traditional hERG1 blockers. Microseconds-long MD simulations followed by experimental mutagenesis elucidated ceramide specific binding locations at the interface between the pore and voltage sensing domains. This region constitutes a unique crevice present in mammalian channels with a non-swapped topology. The combined experimental and simulation data provide evidence for ceramide-induced allosteric modulation of the channel by a conformational selection mechanism.
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Affiliation(s)
- Williams E Miranda
- Centre for Molecular Simulation and Department of Biological Sciences, 507 Campus Drive, University of Calgary, Calgary, AB, Canada
| | - Jiqing Guo
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, 3280 Hospital Dr., University of Calgary, Calgary, AB, Canada
| | - Haydee Mesa-Galloso
- Centre for Molecular Simulation and Department of Biological Sciences, 507 Campus Drive, University of Calgary, Calgary, AB, Canada
| | - Valentina Corradi
- Centre for Molecular Simulation and Department of Biological Sciences, 507 Campus Drive, University of Calgary, Calgary, AB, Canada
| | - James P Lees-Miller
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, 3280 Hospital Dr., University of Calgary, Calgary, AB, Canada
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, 507 Campus Drive, University of Calgary, Calgary, AB, Canada.
| | - Henry J Duff
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, 3280 Hospital Dr., University of Calgary, Calgary, AB, Canada.
| | - Sergei Yu Noskov
- Centre for Molecular Simulation and Department of Biological Sciences, 507 Campus Drive, University of Calgary, Calgary, AB, Canada.
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8
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Miranda WE, Guo J, Mesa Galloso H, Corradi V, Tieleman PD, Duff HJ, Noskov SY. Molecular Mechanism of hERG1 Channel Regulation by Ceramides. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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9
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Kudaibergenova M, Guo J, Khan HM, Zahid F, Lees-Miller J, Noskov SY, Duff HJ. Allosteric Coupling Between Drug Binding and the Aromatic Cassette in the Pore Domain of the hERG1 Channel: Implications for a State-Dependent Blockade. Front Pharmacol 2020; 11:914. [PMID: 32694995 PMCID: PMC7338687 DOI: 10.3389/fphar.2020.00914] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 06/04/2020] [Indexed: 12/18/2022] Open
Abstract
Human-ether-a-go-go-related channel (hERG1) is the pore-forming domain of the delayed rectifier K+ channel in the heart which underlies the IKr current. The channel has been extensively studied due to its propensity to bind chemically diverse group of drugs. The subsequent hERG1 block can lead to a prolongation of the QT interval potentially leading to an abnormal cardiac electrical activity. The recently solved cryo-EM structure featured a striking non-swapped topology of the Voltage-Sensor Domain (VSD) which is packed against the pore-domain as well as a small and hydrophobic intra-cavity space. The small size and hydrophobicity of the cavity was unexpected and challenges the already-established hypothesis of drugs binding to the wide cavity. Recently, we showed that an amphipathic drug, ivabradine, may favorably bind the channel from the lipid-facing surface and we discovered a mutant (M651T) on the lipid facing domain between the VSD and the PD which inhibited the blocking capacity of the drug. Using multi-microseconds Molecular Dynamics (MD) simulations of wild-type and M651T mutant hERG1, we suggested the block of the channel through the lipid mediated pathway, the opening of which is facilitated by the flexible phenylalanine ring (F656). In this study, we characterize the dynamic interaction of the methionine-aromatic cassette in the S5-S6 helices by combining data from electrophysiological experiments with MD simulations and molecular docking to elucidate the complex allosteric coupling between drug binding to lipid-facing and intra-cavity sites and aromatic cassette dynamics. We investigated two well-established hERG1 blockers (ivabradine and dofetilide) for M651 sensitivity through electrophysiology and mutagenesis techniques. Our electrophysiology data reveal insensitivity of dofetilide to the mutations at site M651 on the lipid facing side of the channel, mirroring our results obtained from docking experiments. Moreover, we show that the dofetilide-induced block of hERG1 occurs through the intracellular space, whereas little to no block of ivabradine is observed during the intracellular application of the drug. The dynamic conformational rearrangement of the F656 appears to regulate the translocation of ivabradine into the central cavity. M651T mutation appears to disrupt this entry pathway by altering the molecular conformation of F656.
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Affiliation(s)
- Meruyert Kudaibergenova
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada.,Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Jiqing Guo
- Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Hanif M Khan
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Farhan Zahid
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - James Lees-Miller
- Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Sergei Yu Noskov
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Henry J Duff
- Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
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10
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AlKhaleefa A, Snider FL, Duff HJ, McGhee JD. -Using the C. elegans lem-2 Gene to Reconstruct the Human LEMD2 Mutation Associated with Hutterite-type Cataract/Cardiomyopathy. MicroPubl Biol 2020; 2020. [PMID: 32666044 PMCID: PMC7351585 DOI: 10.17912/micropub.biology.000273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Ayaa AlKhaleefa
- 1. Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta CANADA
| | - Frances L Snider
- 1. Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta CANADA
| | - Henry J Duff
- Cardiac Sciences, Libin Cardiology Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta CANADA
| | - James D McGhee
- 1. Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta CANADA
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11
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Janz A, Chen R, Regensburger M, Ueda Y, Rost S, Klopocki E, Günther K, Edenhofer F, Duff HJ, Ergün S, Gerull B. Generation of two patient-derived iPSC lines from siblings (LIBUCi001-A and LIBUCi002-A) and a genetically modified iPSC line (JMUi001-A-1) to mimic dilated cardiomyopathy with ataxia (DCMA) caused by a homozygous DNAJC19 mutation. Stem Cell Res 2020; 46:101856. [PMID: 32521499 DOI: 10.1016/j.scr.2020.101856] [Citation(s) in RCA: 5] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 05/09/2020] [Accepted: 05/25/2020] [Indexed: 12/21/2022] Open
Abstract
Dilated cardiomyopathy with ataxia (DCMA) is an autosomal recessive disorder arising from mutations in DNAJC19. Two patient-derived dermal fibroblast cell lines of siblings with the same homozygous splice acceptor site mutation in DNAJC19 (NM_145261.4):c.130-1G>C were reprogrammed into induced pluripotent stem cell (iPSC) lines (LIBUCi001-A and LIBUCi002-A) using non-integrative Sendai virus. Additionally, a third DNAJC19tv (truncation variant) iPSC line (JMUi001-A-1) was generated by CRISPR/Cas9 in healthy control iPSCs (JMUi001-A). All three DCMA iPSC lines present normal karyotypes, high expression of pluripotency markers and the capacity to differentiate into cells of all three germ layers.
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Affiliation(s)
- Anna Janz
- Comprehensive Heart Failure Center (CHFC) and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
| | - Ruping Chen
- Comprehensive Heart Failure Center (CHFC) and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
| | - Martina Regensburger
- Comprehensive Heart Failure Center (CHFC) and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
| | - Yuichiro Ueda
- Institute of Anatomy and Cell Biology II, University of Würzburg, Würzburg, Germany
| | - Simone Rost
- Institute of Human Genetics, Biocentre, University of Würzburg, Würzburg, Germany
| | - Eva Klopocki
- Institute of Human Genetics, Biocentre, University of Würzburg, Würzburg, Germany
| | - Katharina Günther
- Institute of Molecular Biology & CMBI, University of Innsbruck, Innsbruck, Austria; Institute of Molecular Regenerative Medicine, Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Frank Edenhofer
- Institute of Molecular Biology & CMBI, University of Innsbruck, Innsbruck, Austria
| | - Henry J Duff
- Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, University of Calgary, Calgary, Canada
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology II, University of Würzburg, Würzburg, Germany
| | - Brenda Gerull
- Comprehensive Heart Failure Center (CHFC) and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany; Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, University of Calgary, Calgary, Canada.
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Miranda WE, Guo J, Corradi V, Mesa Galloso H, Tieleman PD, Duff HJ, Noskov SY. Molecular Mechanisms of Human ERG1 Channel Blockade by Ceramides. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.3038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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13
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Roberts JD, Asaki SY, Mazzanti A, Bos JM, Tuleta I, Muir AR, Crotti L, Krahn AD, Kutyifa V, Shoemaker MB, Johnsrude CL, Aiba T, Marcondes L, Baban A, Udupa S, Dechert B, Fischbach P, Knight LM, Vittinghoff E, Kukavica D, Stallmeyer B, Giudicessi JR, Spazzolini C, Shimamoto K, Tadros R, Cadrin-Tourigny J, Duff HJ, Simpson CS, Roston TM, Wijeyeratne YD, El Hajjaji I, Yousif MD, Gula LJ, Leong-Sit P, Chavali N, Landstrom AP, Marcus GM, Dittmann S, Wilde AAM, Behr ER, Tfelt-Hansen J, Scheinman MM, Perez MV, Kaski JP, Gow RM, Drago F, Aziz PF, Abrams DJ, Gollob MH, Skinner JR, Shimizu W, Kaufman ES, Roden DM, Zareba W, Schwartz PJ, Schulze-Bahr E, Etheridge SP, Priori SG, Ackerman MJ. An International Multicenter Evaluation of Type 5 Long QT Syndrome: A Low Penetrant Primary Arrhythmic Condition. Circulation 2020; 141:429-439. [PMID: 31941373 DOI: 10.1161/circulationaha.119.043114] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Insight into type 5 long QT syndrome (LQT5) has been limited to case reports and small family series. Improved understanding of the clinical phenotype and genetic features associated with rare KCNE1 variants implicated in LQT5 was sought through an international multicenter collaboration. METHODS Patients with either presumed autosomal dominant LQT5 (N = 229) or the recessive Type 2 Jervell and Lange-Nielsen syndrome (N = 19) were enrolled from 22 genetic arrhythmia clinics and 4 registries from 9 countries. KCNE1 variants were evaluated for ECG penetrance (defined as QTc >460 ms on presenting ECG) and genotype-phenotype segregation. Multivariable Cox regression was used to compare the associations between clinical and genetic variables with a composite primary outcome of definite arrhythmic events, including appropriate implantable cardioverter-defibrillator shocks, aborted cardiac arrest, and sudden cardiac death. RESULTS A total of 32 distinct KCNE1 rare variants were identified in 89 probands and 140 genotype positive family members with presumed LQT5 and an additional 19 Type 2 Jervell and Lange-Nielsen syndrome patients. Among presumed LQT5 patients, the mean QTc on presenting ECG was significantly longer in probands (476.9±38.6 ms) compared with genotype positive family members (441.8±30.9 ms, P<0.001). ECG penetrance for heterozygous genotype positive family members was 20.7% (29/140). A definite arrhythmic event was experienced in 16.9% (15/89) of heterozygous probands in comparison with 1.4% (2/140) of family members (adjusted hazard ratio [HR] 11.6 [95% CI, 2.6-52.2]; P=0.001). Event incidence did not differ significantly for Type 2 Jervell and Lange-Nielsen syndrome patients relative to the overall heterozygous cohort (10.5% [2/19]; HR 1.7 [95% CI, 0.3-10.8], P=0.590). The cumulative prevalence of the 32 KCNE1 variants in the Genome Aggregation Database, which is a human database of exome and genome sequencing data from now over 140 000 individuals, was 238-fold greater than the anticipated prevalence of all LQT5 combined (0.238% vs 0.001%). CONCLUSIONS The present study suggests that putative/confirmed loss-of-function KCNE1 variants predispose to QT prolongation, however, the low ECG penetrance observed suggests they do not manifest clinically in the majority of individuals, aligning with the mild phenotype observed for Type 2 Jervell and Lange-Nielsen syndrome patients.
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Affiliation(s)
- Jason D Roberts
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, Western University, London, Ontario, Canada (J.D.R., I.E.H., M.D.Y., L.J.G., P.L.-S.)
| | - S Yukiko Asaki
- Department of Pediatrics, University of Utah, and Primary Children's Hospital, Salt Lake City (S.Y.A., S.P.E.)
| | - Andrea Mazzanti
- Molecular Cardiology, Istituti Clinici Scientifici Maugeri, Istituto di Ricovero e Cura a Carattere Scientifico and Department of Molecular Medicine, University of Pavia, Italy (A.M., D.K., S.G.P.).,European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.)
| | | | - Izabela Tuleta
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.).,Department of Cardiology I (I.T.), University Hospital Muenster, Germany
| | - Alison R Muir
- Northern Ireland Inherited Cardiac Conditions Service, Belfast City Hospital, United Kingdom (A.R.M.)
| | - Lia Crotti
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.).,Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Milan, Italy (L.C., C.S., P.J.S.).,Department of Medicine and Surgery, University of Milano-Bicocca, Italy (L.C.).,Istituto Auxologico Italiano, IRCCS, Department of Cardiovascular, Neural and Metabolic Sciences, San Luca Hospital, Milan, Italy (L.C.)
| | - Andrew D Krahn
- Heart Rhythm Services, Division of Cardiology, Department of Medicine, University of British Columbia, Vancouver, Canada (A.D.K., T.M.R.)
| | - Valentina Kutyifa
- Clinical Cardiovascular Research Center, University of Rochester Medical Center, NY (V.K., W.Z.)
| | - M Benjamin Shoemaker
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN (M.B., J.R.G., M.J.A.).,Departments of Medicine (M.B.S., N.C., D.M.R.), Vanderbilt University Medical Center, Nashville, TN
| | - Christopher L Johnsrude
- Division of Pediatric Cardiology, Department of Pediatrics, University of Louisville, KY (C.L.J.)
| | - Takeshi Aiba
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan (T.A., K.S., W.S.)
| | - Luciana Marcondes
- Cardiac Inherited Disease Group New Zealand, Paediatric and Congenital Cardiac Services, Starship Children's Hospital, Auckland (L.M., J.R.S.)
| | - Anwar Baban
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.).,Pediatric Cardiology and Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology and Cardiac Surgery, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy (A.B., F.D.)
| | - Sharmila Udupa
- Children's Hospital of Eastern Ontario, Department of Pediatrics, University of Ottawa, Canada (S.U., R.M.G.)
| | - Brynn Dechert
- Division of Cardiology, Department of Pediatrics, University of Michigan Children's Hospital, University of Michigan, Ann Arbor (B.D.)
| | - Peter Fischbach
- Children's Healthcare of Atlanta, Sibley Heart Center Cardiology, GA (P.F., L.M.K.)
| | - Linda M Knight
- Children's Healthcare of Atlanta, Sibley Heart Center Cardiology, GA (P.F., L.M.K.)
| | - Eric Vittinghoff
- Department of Epidemiology and Biostatistics (E.V.), University of California San Francisco
| | - Deni Kukavica
- Molecular Cardiology, Istituti Clinici Scientifici Maugeri, Istituto di Ricovero e Cura a Carattere Scientifico and Department of Molecular Medicine, University of Pavia, Italy (A.M., D.K., S.G.P.).,European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.)
| | - Birgit Stallmeyer
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.).,Institute for Genetics of Heart Disease (B.S., S.D., E.S.-B.), University Hospital Muenster, Germany
| | - John R Giudicessi
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN (M.B., J.R.G., M.J.A.)
| | - Carla Spazzolini
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.).,Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Milan, Italy (L.C., C.S., P.J.S.)
| | - Keiko Shimamoto
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan (T.A., K.S., W.S.)
| | - Rafik Tadros
- Cardiovascular Genetics Center, Montreal Heart Institute, Université de Montréal, Quebec, Canada (R.T., J., C.-T.)
| | - Julia Cadrin-Tourigny
- Cardiovascular Genetics Center, Montreal Heart Institute, Université de Montréal, Quebec, Canada (R.T., J., C.-T.)
| | - Henry J Duff
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Canada (H.J.D.)
| | | | - Thomas M Roston
- Heart Rhythm Services, Division of Cardiology, Department of Medicine, University of British Columbia, Vancouver, Canada (A.D.K., T.M.R.)
| | - Yanushi D Wijeyeratne
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.).,Cardiology Clinical Academic Group, Molecular and Clinical Sciences Research Institute, St. George's University of London, and St. George's University Hospitals NHS Foundation Trust, United Kingdom (Y.D.W., E.R.B.)
| | - Imane El Hajjaji
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, Western University, London, Ontario, Canada (J.D.R., I.E.H., M.D.Y., L.J.G., P.L.-S.)
| | - Maisoon D Yousif
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, Western University, London, Ontario, Canada (J.D.R., I.E.H., M.D.Y., L.J.G., P.L.-S.)
| | - Lorne J Gula
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, Western University, London, Ontario, Canada (J.D.R., I.E.H., M.D.Y., L.J.G., P.L.-S.)
| | - Peter Leong-Sit
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, Western University, London, Ontario, Canada (J.D.R., I.E.H., M.D.Y., L.J.G., P.L.-S.)
| | - Nikhil Chavali
- Departments of Medicine (M.B.S., N.C., D.M.R.), Vanderbilt University Medical Center, Nashville, TN
| | - Andrew P Landstrom
- Department of Pediatrics, Division of Pediatric Cardiology, and Department of Cell Biology, Duke University School of Medicine, Durham, NC (A.P.L.)
| | - Gregory M Marcus
- Amsterdam University Medical Centre, location AMC, Heart Center, Department of Clinical and Experimental Cardiology, The Netherlands (G.M.M., A.A.M.W.)
| | - Sven Dittmann
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.).,Institute for Genetics of Heart Disease (B.S., S.D., E.S.-B.), University Hospital Muenster, Germany
| | - Arthur A M Wilde
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.).,Amsterdam University Medical Centre, location AMC, Heart Center, Department of Clinical and Experimental Cardiology, The Netherlands (G.M.M., A.A.M.W.)
| | - Elijah R Behr
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.).,Cardiology Clinical Academic Group, Molecular and Clinical Sciences Research Institute, St. George's University of London, and St. George's University Hospitals NHS Foundation Trust, United Kingdom (Y.D.W., E.R.B.)
| | - Jacob Tfelt-Hansen
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.).,The Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Denmark (J.T.-H.)
| | - Melvin M Scheinman
- Department of Medicine, Division of Cardiology, Section of Cardiac Electrophysiology M.M.S.), University of California San Francisco
| | - Marco V Perez
- Division of Cardiovascular Medicine, Stanford University School of Medicine, CA (M.V.P.)
| | - Juan Pablo Kaski
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.).,Centre for Inherited Cardiovascular Diseases, Great Ormond Street Hospital and UCL Institute of Cardiovascular Science, London, United Kingdom (J.P.K.)
| | - Robert M Gow
- Children's Hospital of Eastern Ontario, Department of Pediatrics, University of Ottawa, Canada (S.U., R.M.G.)
| | - Fabrizio Drago
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.).,Pediatric Cardiology and Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology and Cardiac Surgery, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy (A.B., F.D.)
| | - Peter F Aziz
- Department of Pediatric Cardiology, Cleveland Clinic, OH (P.F.A.)
| | - Dominic J Abrams
- Inherited Cardiac Arrhythmia Program, Boston Children's Hospital, Harvard Medical School, MA (D.J.A.)
| | - Michael H Gollob
- Department of Physiology and Department of Medicine, Toronto General Hospital, University of Toronto, Ontario, Canada (M.H.G.)
| | - Jonathan R Skinner
- Cardiac Inherited Disease Group New Zealand, Paediatric and Congenital Cardiac Services, Starship Children's Hospital, Auckland (L.M., J.R.S.)
| | - Wataru Shimizu
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan (T.A., K.S., W.S.).,Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan (W.S.)
| | - Elizabeth S Kaufman
- The Heart and Vascular Research Center, Metro-Health Campus, Case Western Reserve University, Cleveland, OH (E.S.K.)
| | - Dan M Roden
- Departments of Medicine (M.B.S., N.C., D.M.R.), Vanderbilt University Medical Center, Nashville, TN.,Pharmacology (D.M.R.), Vanderbilt University Medical Center, Nashville, TN.,Biomedical Informatics (D.M.R.), Vanderbilt University Medical Center, Nashville, TN
| | - Wojciech Zareba
- Clinical Cardiovascular Research Center, University of Rochester Medical Center, NY (V.K., W.Z.)
| | - Peter J Schwartz
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.).,Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Milan, Italy (L.C., C.S., P.J.S.)
| | - Eric Schulze-Bahr
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.).,Institute for Genetics of Heart Disease (B.S., S.D., E.S.-B.), University Hospital Muenster, Germany
| | - Susan P Etheridge
- Department of Pediatrics, University of Utah, and Primary Children's Hospital, Salt Lake City (S.Y.A., S.P.E.)
| | - Silvia G Priori
- Molecular Cardiology, Istituti Clinici Scientifici Maugeri, Istituto di Ricovero e Cura a Carattere Scientifico and Department of Molecular Medicine, University of Pavia, Italy (A.M., D.K., S.G.P.).,European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (A.M., I.T., L.C., A.B., D.K., B.S., C.S., Y.D.W., S.D., A.A.M.W., E.R.B., J.T.-H., J.P.K., F.D., P.J.S., E.S.-B., S.G.P.)
| | - Michael J Ackerman
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN (M.B., J.R.G., M.J.A.)
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14
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Kang S, Verma S, Hassanabad AF, Teng G, Belke DD, Dundas JA, Guzzardi DG, Svystonyuk DA, Pattar SS, Park DSJ, Turnbull JD, Duff HJ, Tibbles LA, Cunnington RH, Dyck JRB, Fedak PWM. Direct Effects of Empagliflozin on Extracellular Matrix Remodelling in Human Cardiac Myofibroblasts: Novel Translational Clues to Explain EMPA-REG OUTCOME Results. Can J Cardiol 2019; 36:543-553. [PMID: 31837891 DOI: 10.1016/j.cjca.2019.08.033] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [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] [Received: 04/18/2019] [Revised: 08/24/2019] [Accepted: 08/25/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Empagliflozin, an SGLT2 inhibitor, has shown remarkable reductions in cardiovascular mortality and heart failure admissions (EMPA-REG OUTCOME). However, the mechanism underlying the heart failure protective effects of empagliflozin remains largely unknown. Cardiac fibroblasts play an integral role in the progression of structural cardiac remodelling and heart failure, in part, by regulating extracellular matrix (ECM) homeostasis. The objective of this study was to determine if empagliflozin has a direct effect on human cardiac myofibroblast-mediated ECM remodelling. METHODS Cardiac fibroblasts were isolated via explant culture from human atrial tissue obtained at open heart surgery. Collagen gel contraction assay was used to assess myofibroblast activity. Cell morphology and cell-mediated ECM remodelling was examined with the use of confocal microscopy. Gene expression of profibrotic markers was assessed with the use of reverse-transcription quantitative polymerase chain reaction. RESULTS Empagliflozin significantly attenuated transforming growth factor β1-induced fibroblast activation via collagen gel contraction after 72-hour exposure, with escalating concentrations (0.5 μmol/L, 1 μmol/L, and 5 μmol/L) resulting in greater attenuation. Morphologic assessment showed that myofibroblasts exposed to empagliflozin were smaller in size with shorter and fewer number of extensions, indicative of a more quiescent phenotype. Moreover, empagliflozin significantly attenuated cell-mediated ECM remodelling as measured by collagen fibre alignment index. Gene expression profiling revealed significant suppression of critical profibrotic markers by empagliflozin, including COL1A1, ACTA2, CTGF, FN1, and MMP-2. CONCLUSIONS We provide novel data showing a direct effect of empagliflozin on human cardiac myofibroblast phenotype and function by attenuation of myofibroblast activity and cell-mediated collagen remodelling. These data provide critical insights into the profound effects of empagliflozin as noted in the EMPA-REG OUTCOME study.
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Affiliation(s)
- Sean Kang
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Subodh Verma
- Division of Cardiac Surgery, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Ali Fatehi Hassanabad
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Guoqi Teng
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Darrell D Belke
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Jameson A Dundas
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - David G Guzzardi
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Daniyil A Svystonyuk
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Simranjit S Pattar
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Daniel S J Park
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Jeannine D Turnbull
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Henry J Duff
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Lee Anne Tibbles
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ryan H Cunnington
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jason R B Dyck
- Cardiovascular Research Centre, Mazankowski Alberta Health Institute, Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Paul W M Fedak
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada.
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Kernik DC, Morotti S, Wu H, Garg P, Duff HJ, Kurokawa J, Jalife J, Wu JC, Grandi E, Clancy CE. A computational model of induced pluripotent stem-cell derived cardiomyocytes incorporating experimental variability from multiple data sources. J Physiol 2019; 597:4533-4564. [PMID: 31278749 PMCID: PMC6767694 DOI: 10.1113/jp277724] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 07/05/2019] [Indexed: 12/22/2022] Open
Abstract
Key points Induced pluripotent stem cell‐derived cardiomyocytes (iPSC‐CMs) capture patient‐specific genotype–phenotype relationships, as well as cell‐to‐cell variability of cardiac electrical activity Computational modelling and simulation provide a high throughput approach to reconcile multiple datasets describing physiological variability, and also identify vulnerable parameter regimes We have developed a whole‐cell model of iPSC‐CMs, composed of single exponential voltage‐dependent gating variable rate constants, parameterized to fit experimental iPSC‐CM outputs We have utilized experimental data across multiple laboratories to model experimental variability and investigate subcellular phenotypic mechanisms in iPSC‐CMs This framework links molecular mechanisms to cellular‐level outputs by revealing unique subsets of model parameters linked to known iPSC‐CM phenotypes
Abstract There is a profound need to develop a strategy for predicting patient‐to‐patient vulnerability in the emergence of cardiac arrhythmia. A promising in vitro method to address patient‐specific proclivity to cardiac disease utilizes induced pluripotent stem cell‐derived cardiomyocytes (iPSC‐CMs). A major strength of this approach is that iPSC‐CMs contain donor genetic information and therefore capture patient‐specific genotype–phenotype relationships. A cited detriment of iPSC‐CMs is the cell‐to‐cell variability observed in electrical activity. We postulated, however, that cell‐to‐cell variability may constitute a strength when appropriately utilized in a computational framework to build cell populations that can be employed to identify phenotypic mechanisms and pinpoint key sensitive parameters. Thus, we have exploited variation in experimental data across multiple laboratories to develop a computational framework for investigating subcellular phenotypic mechanisms. We have developed a whole‐cell model of iPSC‐CMs composed of simple model components comprising ion channel models with single exponential voltage‐dependent gating variable rate constants, parameterized to fit experimental iPSC‐CM data for all major ionic currents. By optimizing ionic current model parameters to multiple experimental datasets, we incorporate experimentally‐observed variability in the ionic currents. The resulting population of cellular models predicts robust inter‐subject variability in iPSC‐CMs. This approach links molecular mechanisms to known cellular‐level iPSC‐CM phenotypes, as shown by comparing immature and mature subpopulations of models to analyse the contributing factors underlying each phenotype. In the future, the presented models can be readily expanded to include genetic mutations and pharmacological interventions for studying the mechanisms of rare events, such as arrhythmia triggers. Induced pluripotent stem cell‐derived cardiomyocytes (iPSC‐CMs) capture patient‐specific genotype–phenotype relationships, as well as cell‐to‐cell variability of cardiac electrical activity Computational modelling and simulation provide a high throughput approach to reconcile multiple datasets describing physiological variability, and also identify vulnerable parameter regimes We have developed a whole‐cell model of iPSC‐CMs, composed of single exponential voltage‐dependent gating variable rate constants, parameterized to fit experimental iPSC‐CM outputs We have utilized experimental data across multiple laboratories to model experimental variability and investigate subcellular phenotypic mechanisms in iPSC‐CMs This framework links molecular mechanisms to cellular‐level outputs by revealing unique subsets of model parameters linked to known iPSC‐CM phenotypes
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Affiliation(s)
- Divya C Kernik
- Department of Physiology and Membrane Biology, Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, USA
| | - Stefano Morotti
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - HaoDi Wu
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Priyanka Garg
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Henry J Duff
- Libin Cardiovascular Institute of Alberta, Faculty of Medicine, University of Calgary, Calgary, AB, Canada
| | - Junko Kurokawa
- Department of Bio-Informational Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - José Jalife
- Department of Internal Medicine, Center for Arrhythmia Research, Cardiovascular Research Center, University of Michigan, Ann Arbor, MI, USA.,Centro Nacional de Investigaciones Cardiovasculares (CNIC), and CIBERV, Madrid, Spain
| | - Joseph C Wu
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Eleonora Grandi
- Department of Pharmacology, School of Medicine, University of California, Davis, CA, USA
| | - Colleen E Clancy
- Department of Physiology and Membrane Biology, Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, USA
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16
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Perissinotti L, Guo J, Kudaibergenova M, Lees-Miller J, Ol'khovich M, Sharapova A, Perlovich GL, Muruve DA, Gerull B, Noskov SY, Duff HJ. The Pore-Lipid Interface: Role of Amino-Acid Determinants of Lipophilic Access by Ivabradine to the hERG1 Pore Domain. Mol Pharmacol 2019; 96:259-271. [PMID: 31182542 DOI: 10.1124/mol.118.115642] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 05/28/2019] [Indexed: 12/14/2022] Open
Abstract
Abnormal cardiac electrical activity is a common side effect caused by unintended block of the promiscuous drug target human ether-à-go-go-related gene (hERG1), the pore-forming domain of the delayed rectifier K+ channel in the heart. hERG1 block leads to a prolongation of the QT interval, a phase of the cardiac cycle that underlies myocyte repolarization detectable on the electrocardiogram. Even newly released drugs such as heart-rate lowering agent ivabradine block the rapid delayed rectifier current IKr, prolong action potential duration, and induce potentially lethal arrhythmia known as torsades de pointes. In this study, we describe a critical drug-binding pocket located at the lateral pore surface facing the cellular membrane. Mutations of the conserved M651 residue alter ivabradine-induced block but not by the common hERG1 blocker dofetilide. As revealed by molecular dynamics simulations, binding of ivabradine to a lipophilic pore access site is coupled to a state-dependent reorientation of aromatic residues F557 and F656 in the S5 and S6 helices. We show that the M651 mutation impedes state-dependent dynamics of F557 and F656 aromatic cassettes at the protein-lipid interface, which has a potential to disrupt drug-induced block of the channel. This fundamentally new mechanism coupling the channel dynamics and small-molecule access from the membrane into the hERG1 intracavitary site provides a simple rationale for the well established state-dependence of drug blockade. SIGNIFICANCE STATEMENT: The drug interference with the function of the cardiac hERG channels represents one of the major sources of drug-induced heart disturbances. We found a novel and a critical drug-binding pocket adjacent to a lipid-facing surface of the hERG1 channel, which furthers our molecular understanding of drug-induced QT syndrome.
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Affiliation(s)
- Laura Perissinotti
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada (L.P., M.K., S.Y.N.); Libin Cardiovascular Institute of Alberta (J.G., J.-L.M., H.J.D.) and Snyder Institute for Chronic Diseases (D.A.M.), Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russian Federation (M.O., A.S., G.L.P.); Department of Cardiac Sciences and Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada (B.G.); and Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany (B.G.)
| | - Jiqing Guo
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada (L.P., M.K., S.Y.N.); Libin Cardiovascular Institute of Alberta (J.G., J.-L.M., H.J.D.) and Snyder Institute for Chronic Diseases (D.A.M.), Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russian Federation (M.O., A.S., G.L.P.); Department of Cardiac Sciences and Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada (B.G.); and Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany (B.G.)
| | - Meruyert Kudaibergenova
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada (L.P., M.K., S.Y.N.); Libin Cardiovascular Institute of Alberta (J.G., J.-L.M., H.J.D.) and Snyder Institute for Chronic Diseases (D.A.M.), Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russian Federation (M.O., A.S., G.L.P.); Department of Cardiac Sciences and Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada (B.G.); and Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany (B.G.)
| | - James Lees-Miller
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada (L.P., M.K., S.Y.N.); Libin Cardiovascular Institute of Alberta (J.G., J.-L.M., H.J.D.) and Snyder Institute for Chronic Diseases (D.A.M.), Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russian Federation (M.O., A.S., G.L.P.); Department of Cardiac Sciences and Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada (B.G.); and Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany (B.G.)
| | - Marina Ol'khovich
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada (L.P., M.K., S.Y.N.); Libin Cardiovascular Institute of Alberta (J.G., J.-L.M., H.J.D.) and Snyder Institute for Chronic Diseases (D.A.M.), Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russian Federation (M.O., A.S., G.L.P.); Department of Cardiac Sciences and Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada (B.G.); and Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany (B.G.)
| | - Angelica Sharapova
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada (L.P., M.K., S.Y.N.); Libin Cardiovascular Institute of Alberta (J.G., J.-L.M., H.J.D.) and Snyder Institute for Chronic Diseases (D.A.M.), Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russian Federation (M.O., A.S., G.L.P.); Department of Cardiac Sciences and Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada (B.G.); and Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany (B.G.)
| | - German L Perlovich
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada (L.P., M.K., S.Y.N.); Libin Cardiovascular Institute of Alberta (J.G., J.-L.M., H.J.D.) and Snyder Institute for Chronic Diseases (D.A.M.), Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russian Federation (M.O., A.S., G.L.P.); Department of Cardiac Sciences and Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada (B.G.); and Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany (B.G.)
| | - Daniel A Muruve
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada (L.P., M.K., S.Y.N.); Libin Cardiovascular Institute of Alberta (J.G., J.-L.M., H.J.D.) and Snyder Institute for Chronic Diseases (D.A.M.), Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russian Federation (M.O., A.S., G.L.P.); Department of Cardiac Sciences and Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada (B.G.); and Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany (B.G.)
| | - Brenda Gerull
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada (L.P., M.K., S.Y.N.); Libin Cardiovascular Institute of Alberta (J.G., J.-L.M., H.J.D.) and Snyder Institute for Chronic Diseases (D.A.M.), Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russian Federation (M.O., A.S., G.L.P.); Department of Cardiac Sciences and Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada (B.G.); and Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany (B.G.)
| | - Sergei Yu Noskov
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada (L.P., M.K., S.Y.N.); Libin Cardiovascular Institute of Alberta (J.G., J.-L.M., H.J.D.) and Snyder Institute for Chronic Diseases (D.A.M.), Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russian Federation (M.O., A.S., G.L.P.); Department of Cardiac Sciences and Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada (B.G.); and Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany (B.G.)
| | - Henry J Duff
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada (L.P., M.K., S.Y.N.); Libin Cardiovascular Institute of Alberta (J.G., J.-L.M., H.J.D.) and Snyder Institute for Chronic Diseases (D.A.M.), Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russian Federation (M.O., A.S., G.L.P.); Department of Cardiac Sciences and Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada (B.G.); and Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany (B.G.)
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17
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Brodehl A, Rezazadeh S, Williams T, Munsie NM, Liedtke D, Oh T, Ferrier R, Shen Y, Jones SJM, Stiegler AL, Boggon TJ, Duff HJ, Friedman JM, Gibson WT, Childs SJ, Gerull B. Mutations in ILK, encoding integrin-linked kinase, are associated with arrhythmogenic cardiomyopathy. Transl Res 2019; 208:15-29. [PMID: 30802431 PMCID: PMC7412573 DOI: 10.1016/j.trsl.2019.02.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/17/2019] [Accepted: 02/12/2019] [Indexed: 12/11/2022]
Abstract
Arrhythmogenic cardiomyopathy is a genetic heart muscle disorder characterized by fibro-fatty replacement of cardiomyocytes leading to life-threatening ventricular arrhythmias, heart failure, and sudden cardiac death. Mutations in genes encoding cardiac junctional proteins are known to cause about half of cases, while remaining genetic causes are unknown. Using exome sequencing, we identified 2 missense variants (p.H33N and p.H77Y) that were predicted to be damaging in the integrin-linked kinase (ILK) gene in 2 unrelated families. The p.H33N variant was found to be de novo. ILK links integrins and the actin cytoskeleton, and is essential for the maintenance of normal cardiac function. Both of the new variants are located in the ILK ankyrin repeat domain, which binds to the first LIM domain of the adaptor proteins PINCH1 and PINCH2. In silico binding studies proposed that the human variants disrupt the ILK-PINCH complex. Recombinant mutant ILK expressed in H9c2 rat myoblast cells shows aberrant prominent cytoplasmic localization compared to the wild-type. Expression of human wild-type and mutant ILK under the control of the cardiac-specific cmlc2 promotor in zebrafish shows that p.H77Y and p.P70L, a variant previously reported in a dilated cardiomyopathy family, cause cardiac dysfunction and death by about 2-3 weeks of age. Our findings provide genetic and functional evidence that ILK is a cardiomyopathy disease gene and highlight its relevance for diagnosis and genetic counseling of inherited cardiomyopathies.
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Affiliation(s)
- Andreas Brodehl
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Saman Rezazadeh
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Tatjana Williams
- Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
| | - Nicole M Munsie
- Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Daniel Liedtke
- Institute of Human Genetics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Tracey Oh
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Raechel Ferrier
- Department of Medical Genetics, Alberta Health Services, Calgary, Alberta, Canada
| | - Yaoqing Shen
- Canada's Michael Smith Genome Sciences Centre, Vancouver, British Columbia, Canada
| | - Steven J M Jones
- Canada's Michael Smith Genome Sciences Centre, Vancouver, British Columbia, Canada
| | - Amy L Stiegler
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Titus J Boggon
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Henry J Duff
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Jan M Friedman
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - William T Gibson
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | | | - Sarah J Childs
- Department of Biochemistry and Molecular Biology, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Brenda Gerull
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada; Comprehensive Heart Failure Center and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany.
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18
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Abdelfatah N, Chen R, Duff HJ, Seifer CM, Buffo I, Huculak C, Clarke S, Clegg R, Jassal DS, Gordon PMK, Ober C, Frosk P, Gerull B. Characterization of a Unique Form of Arrhythmic Cardiomyopathy Caused by Recessive Mutation in LEMD2. JACC Basic Transl Sci 2019; 4:204-221. [PMID: 31061923 PMCID: PMC6488817 DOI: 10.1016/j.jacbts.2018.12.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/02/2018] [Accepted: 12/03/2018] [Indexed: 02/08/2023]
Abstract
Nuclear envelope proteins have been shown to play an important role in the pathogenesis of inherited dilated cardiomyopathy. Here, we present a remarkable cardiac phenotype caused by a homozygous LEMD2 mutation in patients of the Hutterite population with juvenile cataract. Mutation carriers develop arrhythmic cardiomyopathy with mild impairment of left ventricular systolic function but severe ventricular arrhythmias leading to sudden cardiac death. Affected cardiac tissue from a deceased patient and fibroblasts exhibit elongated nuclei with abnormal condensed heterochromatin at the periphery. The patient fibroblasts demonstrate cellular senescence and reduced proliferation capacity, which may suggest an involvement of LEM domain containing protein 2 in chromatin remodeling processes and premature aging.
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Key Words
- ACM, arrhythmogenic cardiomyopathy
- BANF, barrier to autointegration factor
- CMR, cardiac magnetic resonance
- DAPI, 4′,6′-diamidino-2-phenylindole
- DCM, dilated cardiomyopathy
- DNA, deoxyribonucleic acid
- EMD, emerin
- ICD, implantable cardioverter-defibrillator
- LEMD2
- LEMD2, LEM domain containing protein 2
- LGE, late gadolinium enhancement
- LMNA, lamin A/C
- LV, left ventricular
- NE, nuclear envelope
- P, passage
- PBS, phosphate-buffered saline
- SAHF, senescence-associated heterochromatin foci
- SNV, single nucleotide variant
- chromatin remodeling
- dilated cardiomyopathy
- eGFP, enhanced green fluorescent protein
- inner nuclear membrane
- sudden death
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Affiliation(s)
- Nelly Abdelfatah
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ruping Chen
- Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
| | - Henry J Duff
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Colette M Seifer
- Section of Cardiology, Department of Internal Medicine, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Ilan Buffo
- Variety Children's Heart Centre, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Cathleen Huculak
- Department of Medical Genetics, Alberta Health Services, Calgary, Alberta, Canada
| | - Stephanie Clarke
- Department of Biochemistry and Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Robin Clegg
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
| | - Davinder S Jassal
- Section of Cardiology, Department of Internal Medicine, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Paul M K Gordon
- Cumming School of Medicine Centre for Health Genomics and Informatics, University of Calgary, Calgary, Alberta, Canada
| | - Carole Ober
- Department of Human Genetics, The University of Chicago, Chicago, Illinois
| | | | - Patrick Frosk
- Department of Biochemistry and Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.,Department of Pediatrics and Child Health, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Brenda Gerull
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany.,Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
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Miranda WE, Duff HJ, Guo J, Vorobyov IV, DeMarco KR, Clancy CE, Yu Noskov S. Molecular Mechanisms of Filter-Level Gating and Loss of Selectivity in hERG1 N629D Mutant from Microseconds MD Simulations. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Perissinotti LL, De Biase PM, Guo J, Yang PC, Lee MC, Clancy CE, Duff HJ, Noskov SY. Determinants of Isoform-Specific Gating Kinetics of hERG1 Channel: Combined Experimental and Simulation Study. Front Physiol 2018; 9:207. [PMID: 29706893 PMCID: PMC5907531 DOI: 10.3389/fphys.2018.00207] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 02/23/2018] [Indexed: 12/22/2022] Open
Abstract
IKr is the rapidly activating component of the delayed rectifier potassium current, the ion current largely responsible for the repolarization of the cardiac action potential. Inherited forms of long QT syndrome (LQTS) (Lees-Miller et al., 1997) in humans are linked to functional modifications in the Kv11.1 (hERG) ion channel and potentially life threatening arrhythmias. There is little doubt now that hERG-related component of IKr in the heart depends on the tetrameric (homo- or hetero-) channels formed by two alternatively processed isoforms of hERG, termed hERG1a and hERG1b. Isoform composition (hERG1a- vs. the b-isoform) has recently been reported to alter pharmacologic responses to some hERG blockers and was proposed to be an essential factor pre-disposing patients for drug-induced QT prolongation. Very little is known about the gating and pharmacological properties of two isoforms in heart membranes. For example, how gating mechanisms of the hERG1a channels differ from that of hERG1b is still unknown. The mechanisms by which hERG 1a/1b hetero-tetramers contribute to function in the heart, or what role hERG1b might play in disease are all questions to be answered. Structurally, the two isoforms differ only in the N-terminal region located in the cytoplasm: hERG1b is 340 residues shorter than hERG1a and the initial 36 residues of hERG1b are unique to this isoform. In this study, we combined electrophysiological measurements for HEK cells, kinetics and structural modeling to tease out the individual contributions of each isoform to Action Potential formation and then make predictions about the effects of having various mixture ratios of the two isoforms. By coupling electrophysiological data with computational kinetic modeling, two proposed mechanisms of hERG gating in two homo-tetramers were examined. Sets of data from various experimental stimulation protocols (HEK cells) were analyzed simultaneously and fitted to Markov-chain models (M-models). The minimization procedure presented here, allowed assessment of suitability of different Markov model topologies and the corresponding parameters that describe the channel kinetics. The kinetics modeling pointed to key differences in the gating kinetics that were linked to the full channel structure. Interactions between soluble domains and the transmembrane part of the channel appeared to be critical determinants of the gating kinetics. The structures of the full channel in the open and closed states were compared for the first time using the recent Cryo-EM resolved structure for full open hERG channel and an homology model for the closed state, based on the highly homolog EAG1 channel. Key potential interactions which emphasize the importance of electrostatic interactions between N-PAS cap, S4-S5, and C-linker are suggested based on the structural analysis. The derived kinetic parameters were later used in higher order models of cells and tissue to track down the effect of varying the ratios of hERG1a and hERG1b on cardiac action potentials and computed electrocardiograms. Simulations suggest that the recovery from inactivation of hERG1b may contribute to its physiologic role of this isoform in the action potential. Finally, the results presented here contribute to the growing body of evidence that hERG1b significantly affects the generation of the cardiac Ikr and plays an important role in cardiac electrophysiology. We highlight the importance of carefully revisiting the Markov models previously proposed in order to properly account for the relative abundance of the hERG1 a- and b- isoforms.
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Affiliation(s)
- Laura L Perissinotti
- Centre for Molecular Simulations, Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada
| | - Pablo M De Biase
- Centre for Molecular Simulations, Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada
| | - Jiqing Guo
- Libin Cardiovascular Institute of Alberta, Faculty of Medicine, University of Calgary, Calgary, AB, Canada
| | - Pei-Chi Yang
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
| | - Miranda C Lee
- Centre for Molecular Simulations, Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada
| | - Colleen E Clancy
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
| | - Henry J Duff
- Libin Cardiovascular Institute of Alberta, Faculty of Medicine, University of Calgary, Calgary, AB, Canada
| | - Sergei Y Noskov
- Centre for Molecular Simulations, Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada
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21
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Komada T, Chung H, Lau A, Platnich JM, Beck PL, Benediktsson H, Duff HJ, Jenne CN, Muruve DA. Macrophage Uptake of Necrotic Cell DNA Activates the AIM2 Inflammasome to Regulate a Proinflammatory Phenotype in CKD. J Am Soc Nephrol 2018; 29:1165-1181. [PMID: 29439156 DOI: 10.1681/asn.2017080863] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 12/19/2017] [Indexed: 11/03/2022] Open
Abstract
Nonmicrobial inflammation contributes to CKD progression and fibrosis. Absent in melanoma 2 (AIM2) is an inflammasome-forming receptor for double-stranded DNA. AIM2 is expressed in the kidney and activated mainly by macrophages. We investigated the potential pathogenic role of the AIM2 inflammasome in kidney disease. In kidneys from patients with diabetic or nondiabetic CKD, immunofluorescence showed AIM2 expression in glomeruli, tubules, and infiltrating leukocytes. In a mouse model of unilateral ureteral obstruction (UUO), Aim2 deficiency attenuated the renal injury, fibrosis, and inflammation observed in wild-type (WT) littermates. In bone marrow chimera studies, UUO induced substantially more tubular injury and IL-1β cleavage in Aim2-/- or WT mice that received WT bone marrow than in WT mice that received Aim2-/- bone marrow. Intravital microscopy of the kidney in LysM(gfp/gfp) mice 5-6 days after UUO demonstrated the significant recruitment of GFP+ proinflammatory macrophages that crawled along injured tubules, engulfed DNA from necrotic cells, and expressed active caspase-1. DNA uptake occurred in large vacuolar structures within recruited macrophages but not resident CX3CR1+ renal phagocytes. In vitro, macrophages that engulfed necrotic debris showed AIM2-dependent activation of caspase-1 and IL-1β, as well as the formation of AIM2+ ASC specks. ASC specks are a hallmark of inflammasome activation. Cotreatment with DNaseI attenuated the increase in IL-1β levels, confirming that DNA was the principal damage-associated molecular pattern in this process. Therefore, the activation of the AIM2 inflammasome by DNA from necrotic cells drives a proinflammatory phenotype that contributes to chronic injury in the kidney.
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Affiliation(s)
- Takanori Komada
- Departments of Medicine.,Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Hyunjae Chung
- Departments of Medicine.,Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Arthur Lau
- Departments of Medicine.,Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Jaye M Platnich
- Departments of Medicine.,Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Paul L Beck
- Departments of Medicine.,Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Hallgrimur Benediktsson
- Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada.,Pathology and Laboratory Medicine
| | | | - Craig N Jenne
- Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada.,Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada; and
| | - Daniel A Muruve
- Departments of Medicine, .,Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
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22
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Kernik DC, Morotti S, Duff HJ, Kurokawa J, Jalife J, Wu JC, Grandi E, Colleen CE. A Computational Analysis of Inter-Subject Variability in Induced Pluripotent Stem Cell-Derived Cardiomyocytes. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.2602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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23
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Rezazadeh S, Duff HJ. Genetic Determinants of Hereditary Bradyarrhythmias: A Contemporary Review of a Diverse Group of Disorders. Can J Cardiol 2017; 33:758-767. [PMID: 28545623 DOI: 10.1016/j.cjca.2017.03.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/03/2017] [Accepted: 03/10/2017] [Indexed: 11/25/2022] Open
Abstract
Bradyarrhythmia is a common clinical presentation. Although the majority of cases are acquired, genetic screening of families with bradyarrhythmia has led to the discovery of a growing number of causative hereditary mutations. These mutations can interfere with any of the steps required for the occurrence of each cardiac cycle, including generation of an action potential in the sinoatrial node, successful exit of the action potential from the node, propagation of the action potential throughout the atria until the depolarization waves reach the atrioventricular node, and finally transmission of the action potential to the ventricles through the His-Purkinje system. As expected, channelopathies are the predominant culprit for hereditary bradyarrhythmias, because they play a crucial role in action potential generation and propagation. Interestingly, there are an increasing number of genes that encode for various regulatory or structural cellular components that have been linked to hereditary bradyarrhythmias. Furthermore, population-based genetic screening has revealed that age-related conduction defects may in fact be caused by genetic predispositions rather than the simple process of aging. With recent advances in genetic testing and the creation of animal models, not only have we discovered new culprit genes but it has also has become evident that there are still significant gaps in our knowledge of cardiac pathophysiology. In this review, we discuss the clinical presentations of known hereditary bradyarrhythmias and their associated conditions in addition to detailing our current molecular understanding of the mechanisms by which they are manifested.
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Affiliation(s)
- Saman Rezazadeh
- Department of Cardiac Sciences and Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Henry J Duff
- Department of Cardiac Sciences and Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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24
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Rezazadeh S, Guo J, Duff HJ, Ferrier RA, Gerull B. Reversible Dilated Cardiomyopathy Caused by a High Burden of Ventricular Arrhythmias in Andersen-Tawil Syndrome. Can J Cardiol 2016; 32:1576.e15-1576.e18. [DOI: 10.1016/j.cjca.2016.07.587] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/19/2016] [Accepted: 07/19/2016] [Indexed: 02/06/2023] Open
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25
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Guo J, Cheng YM, Lees-Miller JP, Perissinotti LL, Claydon TW, Hull CM, Thouta S, Roach DE, Durdagi S, Noskov SY, Duff HJ. NS1643 interacts around L529 of hERG to alter voltage sensor movement on the path to activation. Biophys J 2016; 108:1400-1413. [PMID: 25809253 DOI: 10.1016/j.bpj.2014.12.055] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 11/25/2014] [Accepted: 12/08/2014] [Indexed: 12/17/2022] Open
Abstract
Activators of hERG1 such as NS1643 are being developed for congenital/acquired long QT syndrome. Previous studies identify the neighborhood of L529 around the voltage-sensor as a putative interacting site for NS1643. With NS1643, the V1/2 of activation of L529I (-34 ± 4 mV) is similar to wild-type (WT) (-37 ± 3 mV; P > 0.05). WT and L529I showed no difference in the slope factor in the absence of NS1643 (8 ± 0 vs. 9 ± 0) but showed a difference in the presence of NS1643 (9 ± 0.3 vs. 22 ± 1; P < 0.01). Voltage-clamp-fluorimetry studies also indicated that in L529I, NS1643 reduces the voltage-sensitivity of S4 movement. To further assess mechanism of NS1643 action, mutations were made in this neighborhood. NS1643 shifts the V1/2 of activation of both K525C and K525C/L529I to hyperpolarized potentials (-131 ± 4 mV for K525C and -120 ± 21 mV for K525C/L529I). Both K525C and K525C/K529I had similar slope factors in the absence of NS1643 (18 ± 2 vs. 34 ± 5, respectively) but with NS1643, the slope factor of K525C/L529I increased from 34 ± 5 to 71 ± 10 (P < 0.01) whereas for K525C the slope factor did not change (18 ± 2 at baseline and 16 ± 2 for NS1643). At baseline, K525R had a slope factor similar to WT (9 vs. 8) but in the presence of NS1643, the slope factor of K525R was increased to 24 ± 4 vs. 9 ± 0 mV for WT (P < 0.01). Molecular modeling indicates that L529I induces a kink in the S4 voltage-sensor helix, altering a salt-bridge involving K525. Moreover, docking studies indicate that NS1643 binds to the kinked structure induced by the mutation with a higher affinity. Combining biophysical, computational, and electrophysiological evidence, a mechanistic principle governing the action of some activators of hERG1 channels is proposed.
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Affiliation(s)
- Jiqing Guo
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Yen May Cheng
- Department of Biomedical Physiology and Kinesiology, Molecular Cardiac Physiology Group, Simon Fraser University, Burnaby, British Columbia, Canada
| | - James P Lees-Miller
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Laura L Perissinotti
- Centre for Molecular Simulations, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Tom W Claydon
- Department of Biomedical Physiology and Kinesiology, Molecular Cardiac Physiology Group, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Christina M Hull
- Department of Biomedical Physiology and Kinesiology, Molecular Cardiac Physiology Group, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Samrat Thouta
- Department of Biomedical Physiology and Kinesiology, Molecular Cardiac Physiology Group, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Daniel E Roach
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Serdar Durdagi
- Centre for Molecular Simulations, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Sergei Y Noskov
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada; Centre for Molecular Simulations, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
| | - Henry J Duff
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada.
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Duff HJ. Dynamic Clamp: Insights From State-of-the-Art Experimentation. Circ Arrhythm Electrophysiol 2015; 8:1012-3. [PMID: 26487621 DOI: 10.1161/circep.115.003298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Henry J Duff
- From the Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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27
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Lees-Miller JP, Guo J, Wang Y, Perissinotti LL, Noskov SY, Duff HJ. In response to Melgari et al. "hERG potassium channel inhibition by ivabradine requires channel gating". J Mol Cell Cardiol 2015; 87:192-3. [PMID: 26299838 DOI: 10.1016/j.yjmcc.2015.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 08/03/2015] [Indexed: 11/20/2022]
Affiliation(s)
- James P Lees-Miller
- Libin Cardiovascular Institute, Department of Medicine, University of Calgary, AB, Canada
| | - Jiqing Guo
- Libin Cardiovascular Institute, Department of Medicine, University of Calgary, AB, Canada
| | - Yibo Wang
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, AB, Canada
| | - Laura L Perissinotti
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, AB, Canada
| | - Sergei Y Noskov
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, AB, Canada.
| | - Henry J Duff
- Libin Cardiovascular Institute, Department of Medicine, University of Calgary, AB, Canada.
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28
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Lees-Miller JP, Guo J, Wang Y, Perissinotti LL, Noskov SY, Duff HJ. Ivabradine prolongs phase 3 of cardiac repolarization and blocks the hERG1 (KCNH2) current over a concentration-range overlapping with that required to block HCN4. J Mol Cell Cardiol 2015; 85:71-8. [DOI: 10.1016/j.yjmcc.2015.05.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 05/08/2015] [Accepted: 05/11/2015] [Indexed: 10/23/2022]
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29
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Abstract
SIGNIFICANCE Persistent nonmicrobial tissue injury leads to the nonlinear activation of integrated wound-healing pathways. In chronic cardiovascular diseases, local tissue undergoes dynamic remodeling involving both structural cells and professional innate immune cells in attempts to limit burden of injury. While the final effector mechanisms by which these different cellular populations participate in wound healing are functionally distinct, their upstream molecular signaling pathways can often be shared. RECENT ADVANCES The NOD-like receptors (NLRs) are intracellular pattern recognition receptors that have been well characterized as key regulators of pro-inflammatory cytokine production in innate immune cells. However, recent evidence has shown that some NLR proteins are additionally expressed by resident structural cells despite negligible cytokine production. These results indicate the potential for noncanonical routes of innate immune signaling by NLRs within solid organ systems. CRITICAL ISSUES Here, we review the emerging functions of NLR proteins in professional immune and tissue-resident cells, and discuss the implications in wound healing during chronic cardiovascular diseases. Emphasis is placed on NLRP3 and its regulation of cardiac structure and function in response to injury. Specific cellular and subcellular signaling paradigms are also discussed. FUTURE DIRECTIONS The characterization of how NLRs participate in homeostasis during cellular injury is essential to develop their potential utility for therapeutic intervention in cardiovascular disease.
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Affiliation(s)
- Nathan A Bracey
- 1 Department of Medicine, Snyder Institute for Chronic Diseases , University of Calgary, Calgary, Canada
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30
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Teng G, Svystonyuk D, Mewhort HEM, Turnbull JD, Belke DD, Duff HJ, Fedak PWM. Tetrandrine reverses human cardiac myofibroblast activation and myocardial fibrosis. Am J Physiol Heart Circ Physiol 2015; 308:H1564-74. [PMID: 25862829 DOI: 10.1152/ajpheart.00126.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 04/03/2015] [Indexed: 11/22/2022]
Abstract
Tetrandrine (TTD) is a calcium channel blocker with documented antifibrotic actions. In this study, for the first time, we identified that TTD can directly prevent in vitro human cardiac myofibroblast activation and limit in vivo myocardial fibrosis. In vitro, cardiac myofibroblasts from human atrial biopsies (N = 10) were seeded in three-dimensional collagen matrices. Cell-collagen constructs were exposed to transforming growth factor-β1 (10 ng/ml), with or without TTD (1 and 5 μM) for 48 h. Collagen gel contraction, myofibroblast activation (α-smooth muscle actin expression), expression of profibrotic mRNAs, and rate of collagen protein synthesis were compared. TTD decreased collagen gel contraction (79.7 ± 1.3 vs 60.1 ± 8.9%, P < 0.01), α-smooth muscle actin expression (flow cytometry), collagen synthesis ([(3)H]proline incorporation), and collagen mRNA expression. Cell viability was similar between groups (annexin positive cells: 1.7 vs. 1.4%). TTD inhibited collagen gel contraction in the presence of T-type and L-type calcium channel blockers, and the intracellular calcium chelator BAPTA-AM (15 μM), suggesting that the observed effects are not mediated by calcium homeostasis. In vivo, Dahl salt-sensitive hypertensive rats were treated with variable doses of TTD (by intraperitoneal injection over 4 wk) and compared with untreated controls (N = 12). Systemic blood pressure was monitored by tail cuff. Myocardial fibrosis and left ventricular compliance were assessed by histology and passive pressure-volume analysis. Myocardial fibrosis was attenuated compared with untreated controls (%collagen area: 9.4 ± 7.3 vs 2.1 ± 1.0%, P < 0.01). Left ventricular compliance was preserved. In conclusion, TTD reverses human cardiac myofibroblast activation and myocardial fibrosis, independent of calcium channel blockade.
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Affiliation(s)
- Guoqi Teng
- Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
| | - Daniyil Svystonyuk
- Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
| | - Holly E M Mewhort
- Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
| | - Jeannine D Turnbull
- Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
| | - Darrell D Belke
- Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
| | - Henry J Duff
- Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
| | - Paul W M Fedak
- Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
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31
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Kim DY, Abdelwahab MG, Lee SH, O’Neill D, Thompson RJ, Duff HJ, Sullivan PG, Rho JM. Ketones prevent oxidative impairment of hippocampal synaptic integrity through KATP channels. PLoS One 2015; 10:e0119316. [PMID: 25848768 PMCID: PMC4388385 DOI: 10.1371/journal.pone.0119316] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 01/29/2015] [Indexed: 12/31/2022] Open
Abstract
Dietary and metabolic therapies are increasingly being considered for a variety of neurological disorders, based in part on growing evidence for the neuroprotective properties of the ketogenic diet (KD) and ketones. Earlier, we demonstrated that ketones afford hippocampal synaptic protection against exogenous oxidative stress, but the mechanisms underlying these actions remain unclear. Recent studies have shown that ketones may modulate neuronal firing through interactions with ATP-sensitive potassium (KATP) channels. Here, we used a combination of electrophysiological, pharmacological, and biochemical assays to determine whether hippocampal synaptic protection by ketones is a consequence of KATP channel activation. Ketones dose-dependently reversed oxidative impairment of hippocampal synaptic integrity, neuronal viability, and bioenergetic capacity, and this action was mirrored by the KATP channel activator diazoxide. Inhibition of KATP channels reversed ketone-evoked hippocampal protection, and genetic ablation of the inwardly rectifying K+ channel subunit Kir6.2, a critical component of KATP channels, partially negated the synaptic protection afforded by ketones. This partial protection was completely reversed by co-application of the KATP blocker, 5-hydoxydecanoate (5HD). We conclude that, under conditions of oxidative injury, ketones induce synaptic protection in part through activation of KATP channels.
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Affiliation(s)
- Do Young Kim
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital & Medical Center, Phoenix, Arizona, United States of America
- * E-mail:
| | - Mohammed G. Abdelwahab
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital & Medical Center, Phoenix, Arizona, United States of America
| | - Soo Han Lee
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital & Medical Center, Phoenix, Arizona, United States of America
| | - Derek O’Neill
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital & Medical Center, Phoenix, Arizona, United States of America
| | - Roger J. Thompson
- Departments of Cell Biology and Anatomy, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Henry J. Duff
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Patrick G. Sullivan
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - Jong M. Rho
- Departments of Pediatrics and Clinical Neurosciences, Alberta Children’s Hospital, Calgary, Alberta, Canada
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Teng G, Zhao X, Lees-Miller JP, Belke D, Shi C, Chen Y, O’Brien ER, Fedak PW, Bracey N, Cross JC, Duff HJ. Role of Mutation and Pharmacologic Block of Human KCNH2 in Vasculogenesis and Fetal Mortality. Circ Arrhythm Electrophysiol 2015; 8:420-8. [DOI: 10.1161/circep.114.001837] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 01/20/2015] [Indexed: 11/16/2022]
Abstract
Background—
N629D
KCNH2
is a human missense long-QT2 mutation. Previously, we reported that the N629D/N629D mutation embryos disrupted cardiac looping, right ventricle development, and ablated I
Kr
activity at E9.5. The present study evaluates the role of KCNH2 in vasculogenesis.
Methods and Results—
N629D/N629D yolk sac vessels and aorta consist of sinusoids without normal arborization. Isolated E9.5 +/+ first branchial arches showed normal outgrowth of mouse ERG–positive/α-smooth muscle actin coimmunolocalized cells; however, outgrowth was grossly reduced in N629D/N629D. N629D/N629D aortas showed fewer α-smooth muscle actin positive cells that were not coimmunolocalized with mouse ERG cells. Transforming growth factor-β treatment of isolated N629D/N629D embryoid bodies partially rescued this phenotype. Cultured N629D/N629D embryos recapitulate the same cardiovascular phenotypes as seen in vivo. Transforming growth factor-β treatment significantly rescued these embryonic phenotypes. Both in vivo and in vitro, dofetilide treatment, over a narrow window of time, entirely recapitulated the N629D/N629D fetal phenotypes. Exogenous transforming growth factor-β treatment also rescued the dofetilide-induced phenotype toward normal.
Conclusions—
Loss of function of KCNH2 mutations results in defects in cardiogenesis and vasculogenesis. Because many medications inadvertently block the KCNH2 potassium current, these novel findings seem to have clinical relevance.
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Affiliation(s)
- Guoqi Teng
- From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O’B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada
| | - Xiang Zhao
- From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O’B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada
| | - James P. Lees-Miller
- From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O’B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada
| | - Darrell Belke
- From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O’B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada
| | - Chunhua Shi
- From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O’B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada
| | - Yongxiang Chen
- From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O’B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada
| | - Edward R. O’Brien
- From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O’B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada
| | - Paul W. Fedak
- From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O’B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada
| | - Nathan Bracey
- From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O’B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada
| | - James C. Cross
- From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O’B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada
| | - Henry J. Duff
- From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O’B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada
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33
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Perissinotti LL, Guo J, De Biase PM, Clancy CE, Duff HJ, Noskov SY. Kinetic model for NS1643 drug activation of WT and L529I variants of Kv11.1 (hERG1) potassium channel. Biophys J 2015; 108:1414-1424. [PMID: 25809254 PMCID: PMC4375712 DOI: 10.1016/j.bpj.2014.12.056] [Citation(s) in RCA: 21] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 11/24/2014] [Accepted: 12/08/2014] [Indexed: 11/28/2022] Open
Abstract
Congenital and acquired (drug-induced) forms of the human long-QT syndrome are associated with alterations in Kv11.1 (hERG) channel-controlled repolarizing IKr currents of cardiac action potentials. A mandatory drug screen implemented by many countries led to a discovery of a large group of small molecules that can activate hERG currents and thus may act as potent antiarrhythmic agents. Despite significant progress in identification of channel activators, little is known about their mechanism of action. A combination of electrophysiological studies with molecular and kinetic modeling was used to examine the mechanism of a model activator (NS1643) action on the hERG channel and its L529I mutant. The L529I mutant has gating dynamics similar to that of wild-type while its response to application of NS1643 is markedly different. We propose a mechanism compatible with experiments in which the model activator binds to the closed (C3) and open states (O). We suggest that NS1643 is affecting early gating transitions, probably during movements of the voltage sensor that precede the opening of the activation gate.
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Affiliation(s)
- Laura L Perissinotti
- Centre for Molecular Modeling, Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
| | - Jiqing Guo
- Libin Cardiovascular Institute of Alberta, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Pablo M De Biase
- Centre for Molecular Modeling, Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
| | - Colleen E Clancy
- Department of Pharmacology, University of California at Davis, Davis, California.
| | - Henry J Duff
- Libin Cardiovascular Institute of Alberta, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada.
| | - Sergei Y Noskov
- Centre for Molecular Modeling, Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada.
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Wang Y, Perissinotti L, Guo J, Duff HJ, Yu Noskov S. Molecular Origins of State-Dependent Herg1 Blockade by Dofetilide. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Wong JA, Duff HJ, Yuen T, Kolman L, Exner DV, Weeks SG, Gerull B. Phenotypic analysis of arrhythmogenic cardiomyopathy in the Hutterite population: role of electrocardiogram in identifying high-risk desmocollin-2 carriers. J Am Heart Assoc 2014; 3:e001407. [PMID: 25497880 PMCID: PMC4338736 DOI: 10.1161/jaha.114.001407] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background The p.Gln554X mutation in desmocollin‐2 (DSC2) is prevalent in ≈10% of the
Hutterite population. While the homozygous mutation causes severe biventricular arrhythmogenic right
ventricular cardiomyopathy, the phenotypic features and prognosis of heterozygotes remain
incompletely understood. Methods and Results Eleven homozygotes (mean age 32±8 years, 45% female), 28 heterozygotes (mean age
40±15 years, 50% female), and 22 mutation‐negatives (mean age 43±17
years, 41% female) were examined. Diagnostic testing was performed as per the arrhythmogenic
right ventricular cardiomyopathy modified Task Force Criteria. Inverted T waves in the right
precordial leads on ECG were seen in all homozygotes but not in their counterparts
(P<0.001). Homozygotes had higher median daily premature ventricular complex
burden than did heterozygotes or mutation‐negatives (1407 [IQR 1080 to 2936] versus 2 [IQR 0
to 6] versus 6 [IQR 0 to 214], P=0.0002). Ventricular tachycardia was
observed in 60% of homozygotes but in none of the remaining individuals
(P<0.001). On cardiac magnetic resonance imaging, homozygotes had
significantly larger indexed end‐diastolic volumes (right ventricular: 122±24 versus
83±17 versus 83±12 mL/m2, P<0.0001; left
ventricular: 93±18 versus 76±13 versus 80±11 mL/m2,
P=0.0124) and lower ejection fraction values compared with heterozygotes and
mutation‐negatives (right ventricular ejection fraction: 41±9% versus
59±9% versus 61±6%, P<0.0001; left ventricular
ejection fraction: 53±8% versus 65±5% versus 64±5%,
P<0.0001). Most affected individuals lacked right ventricular wall motion
abnormalities. Thus, few met cardiac magnetic resonance imaging task force criteria. Conclusions The ECG reliably identifies homozygous p.Gln554X carriers and may be useful as an initial step in
the screening of high‐risk Hutterites. The cardiac phenotype of heterozygotes appears benign,
but further prospective follow‐up of their arrhythmic risk is needed.
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Affiliation(s)
- Jorge A Wong
- Libin Cardiovascular Institute of Alberta & Department of Cardiac Sciences, University of Calgary, Alberta, Canada (J.A.W., H.J.D., T.Y., L.K., D.V.E., S.G.W., B.G.)
| | - Henry J Duff
- Libin Cardiovascular Institute of Alberta & Department of Cardiac Sciences, University of Calgary, Alberta, Canada (J.A.W., H.J.D., T.Y., L.K., D.V.E., S.G.W., B.G.)
| | - Tiffany Yuen
- Libin Cardiovascular Institute of Alberta & Department of Cardiac Sciences, University of Calgary, Alberta, Canada (J.A.W., H.J.D., T.Y., L.K., D.V.E., S.G.W., B.G.)
| | - Louis Kolman
- Libin Cardiovascular Institute of Alberta & Department of Cardiac Sciences, University of Calgary, Alberta, Canada (J.A.W., H.J.D., T.Y., L.K., D.V.E., S.G.W., B.G.)
| | - Derek V Exner
- Libin Cardiovascular Institute of Alberta & Department of Cardiac Sciences, University of Calgary, Alberta, Canada (J.A.W., H.J.D., T.Y., L.K., D.V.E., S.G.W., B.G.)
| | - Sarah G Weeks
- Libin Cardiovascular Institute of Alberta & Department of Cardiac Sciences, University of Calgary, Alberta, Canada (J.A.W., H.J.D., T.Y., L.K., D.V.E., S.G.W., B.G.)
| | - Brenda Gerull
- Libin Cardiovascular Institute of Alberta & Department of Cardiac Sciences, University of Calgary, Alberta, Canada (J.A.W., H.J.D., T.Y., L.K., D.V.E., S.G.W., B.G.)
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Guo J, Durdagi S, Changalov M, Perissinotti LL, Hargreaves JM, Back TG, Noskov SY, Duff HJ. Structure driven design of novel human ether-a-go-go-related-gene channel (hERG1) activators. PLoS One 2014; 9:e105553. [PMID: 25191697 PMCID: PMC4156305 DOI: 10.1371/journal.pone.0105553] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [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: 04/10/2014] [Accepted: 07/22/2014] [Indexed: 01/01/2023] Open
Abstract
One of the main culprits in modern drug discovery is apparent cardiotoxicity of many lead-candidates via inadvertent pharmacologic blockade of K+, Ca2+ and Na+ currents. Many drugs inadvertently block hERG1 leading to an acquired form of the Long QT syndrome and potentially lethal polymorphic ventricular tachycardia. An emerging strategy is to rely on interventions with a drug that may proactively activate hERG1 channels reducing cardiovascular risks. Small molecules-activators have a great potential for co-therapies where the risk of hERG-related QT prolongation is significant and rehabilitation of the drug is impractical. Although a number of hERG1 activators have been identified in the last decade, their binding sites, functional moieties responsible for channel activation and thus mechanism of action, have yet to be established. Here, we present a proof-of-principle study that combines de-novo drug design, molecular modeling, chemical synthesis with whole cell electrophysiology and Action Potential (AP) recordings in fetal mouse ventricular myocytes to establish basic chemical principles required for efficient activator of hERG1 channel. In order to minimize the likelihood that these molecules would also block the hERG1 channel they were computationally engineered to minimize interactions with known intra-cavitary drug binding sites. The combination of experimental and theoretical studies led to identification of functional elements (functional groups, flexibility) underlying efficiency of hERG1 activators targeting binding pocket located in the S4–S5 linker, as well as identified potential side-effects in this promising line of drugs, which was associated with multi-channel targeting of the developed drugs.
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Affiliation(s)
- Jiqing Guo
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Serdar Durdagi
- Centre for Molecular Simulation, Biochemistry Research Cluster, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
- Department of Biophysics, School of Medicine, Bahcesehir University, Istanbul, Turkey
| | - Mohamed Changalov
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada
| | - Laura L. Perissinotti
- Centre for Molecular Simulation, Biochemistry Research Cluster, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | | | - Thomas G. Back
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada
- * E-mail: (TGB); (SYN); (HJD)
| | - Sergei Y. Noskov
- Centre for Molecular Simulation, Biochemistry Research Cluster, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
- * E-mail: (TGB); (SYN); (HJD)
| | - Henry J. Duff
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
- * E-mail: (TGB); (SYN); (HJD)
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Ezekowitz JA, Becher H, Belenkie I, Clark AM, Duff HJ, Friedrich MG, Haykowsky MJ, Howlett JG, Kassiri Z, Kaul P, Kim DH, Knudtson ML, Light PE, Lopaschuk GD, McAlister FA, Noga ML, Oudit GY, Paterson DI, Quan H, Schulz R, Thompson RB, Weeks SG, Anderson TJ, Dyck JRB. The Alberta Heart Failure Etiology and Analysis Research Team (HEART) study. BMC Cardiovasc Disord 2014; 14:91. [PMID: 25063541 PMCID: PMC4222863 DOI: 10.1186/1471-2261-14-91] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 07/16/2014] [Indexed: 01/06/2023] Open
Abstract
Background Nationally, symptomatic heart failure affects 1.5-2% of Canadians, incurs $3 billion in hospital costs annually and the global burden is expected to double in the next 1–2 decades. The current one-year mortality rate after diagnosis of heart failure remains high at >25%. Consequently, new therapeutic strategies need to be developed for this debilitating condition. Methods/Design The objective of the Alberta HEART program (http://albertaheartresearch.ca) is to develop novel diagnostic, therapeutic and prognostic approaches to patients with heart failure with preserved ejection fraction. We hypothesize that novel imaging techniques and biomarkers will aid in describing heart failure with preserved ejection fraction. Furthermore, the development of new diagnostic criteria will allow us to: 1) better define risk factors associated with heart failure with preserved ejection fraction; 2) elucidate clinical, cellular and molecular mechanisms involved with the development and progression of heart failure with preserved ejection fraction; 3) design and test new therapeutic strategies for patients with heart failure with preserved ejection fraction. Additionally, Alberta HEART provides training and education for enhancing translational medicine, knowledge translation and clinical practice in heart failure. This is a prospective observational cohort study of patients with, or at risk for, heart failure. Patients will have sequential testing including quality of life and clinical outcomes over 12 months. After that time, study participants will be passively followed via linkage to external administrative databases. Clinical outcomes of interest include death, hospitalization, emergency department visits, physician resource use and/or heart transplant. Patients will be followed for a total of 5 years. Discussion Alberta HEART has the primary objective to define new diagnostic criteria for patients with heart failure with preserved ejection fraction. New criteria will allow for targeted therapies, diagnostic tests and further understanding of the patients, both at-risk for and with heart failure. Trial registration ClinicalTrials.gov NCT02052804.
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Affiliation(s)
- Justin A Ezekowitz
- Mazankowski Alberta Heart Institute, 2C2 WMC, 8440-112 Street, Edmonton, AB, Canada.
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Bracey NA, Gershkovich B, Chun J, Vilaysane A, Meijndert HC, Wright JR, Fedak PW, Beck PL, Muruve DA, Duff HJ. Mitochondrial NLRP3 protein induces reactive oxygen species to promote Smad protein signaling and fibrosis independent from the inflammasome. J Biol Chem 2014; 289:19571-84. [PMID: 24841199 DOI: 10.1074/jbc.m114.550624] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Nucleotide-binding domain and leucine-rich repeat containing PYD-3 (NLRP3) is a pattern recognition receptor that is implicated in the pathogenesis of inflammation and chronic diseases. Although much is known regarding the NLRP3 inflammasome that regulates proinflammatory cytokine production in innate immune cells, the role of NLRP3 in non-professional immune cells is unclear. Here we report that NLRP3 is expressed in cardiac fibroblasts and increased during TGFβ stimulation. NLRP3-deficient cardiac fibroblasts displayed impaired differentiation and R-Smad activation in response to TGFβ. Only the central nucleotide binding domain of NLRP3 was required to augment R-Smad signaling because the N-terminal Pyrin or C-terminal leucine-rich repeat domains were dispensable. Interestingly, NLRP3 regulation of myofibroblast differentiation proceeded independently from the inflammasome, IL-1β/IL-18, or caspase 1. Instead, mitochondrially localized NLRP3 potentiated reactive oxygen species to augment R-Smad activation. In vivo, NLRP3-deficient mice were protected against angiotensin II-induced cardiac fibrosis with preserved cardiac architecture and reduced collagen 1. Together, these results support a distinct role for NLRP3 in non-professional immune cells independent from the inflammasome to regulate differential aspects of wound healing and chronic disease.
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Affiliation(s)
| | | | | | | | | | - James R Wright
- Department of Pathology and Laboratory Medicine, The University of Calgary, Calgary, Alberta T2N 4N1, Canada
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Durdagi S, Randall T, Duff HJ, Chamberlin A, Noskov SY. Rehabilitating drug-induced long-QT promoters: in-silico design of hERG-neutral cisapride analogues with retained pharmacological activity. BMC Pharmacol Toxicol 2014; 15:14. [PMID: 24606761 PMCID: PMC4016140 DOI: 10.1186/2050-6511-15-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 02/24/2014] [Indexed: 02/05/2023] Open
Abstract
Background The human ether-a-go-go related gene 1 (hERG1), which codes for a potassium ion channel, is a key element in the cardiac delayed rectified potassium current, IKr, and plays an important role in the normal repolarization of the heart’s action potential. Many approved drugs have been withdrawn from the market due to their prolongation of the QT interval. Most of these drugs have high potencies for their principal targets and are often irreplaceable, thus “rehabilitation” studies for decreasing their high hERG1 blocking affinities, while keeping them active at the binding sites of their targets, have been proposed to enable these drugs to re-enter the market. Methods In this proof-of-principle study, we focus on cisapride, a gastroprokinetic agent withdrawn from the market due to its high hERG1 blocking affinity. Here we tested an a priori strategy to predict a compound’s cardiotoxicity using de novo drug design with molecular docking and Molecular Dynamics (MD) simulations to generate a strategy for the rehabilitation of cisapride. Results We focused on two key receptors, a target interaction with the (adenosine) receptor and an off-target interaction with hERG1 channels. An analysis of the fragment interactions of cisapride at human A2A adenosine receptors and hERG1 central cavities helped us to identify the key chemical groups responsible for the drug activity and hERG1 blockade. A set of cisapride derivatives with reduced cardiotoxicity was then proposed using an in-silico two-tier approach. This set was compared against a large dataset of commercially available cisapride analogs and derivatives. Conclusions An interaction decomposition of cisapride and cisapride derivatives allowed for the identification of key active scaffolds and functional groups that may be responsible for the unwanted blockade of hERG1.
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Affiliation(s)
- Serdar Durdagi
- Centre for Molecular Simulations and Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
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40
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Duff HJ. Beyond doctrine and dogma: one gene--multisystem effects. Circ Cardiovasc Genet 2014; 7:4. [PMID: 24550429 DOI: 10.1161/circgenetics.114.000508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Henry J Duff
- Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
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Gerull B, Kirchner F, Chong JX, Tagoe J, Chandrasekharan K, Strohm O, Waggoner D, Ober C, Duff HJ. Homozygous Founder Mutation in Desmocollin-2 (
DSC2
) Causes Arrhythmogenic Cardiomyopathy in the Hutterite Population. ACTA ACUST UNITED AC 2013; 6:327-36. [DOI: 10.1161/circgenetics.113.000097] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Dominant mutations in cellular junction proteins are the major cause of arrhythmogenic cardiomyopathy, whereas recessive mutations in those proteins cause cardiocutaneous syndromes such as Naxos and Carvajal syndrome. The Hutterites are distinct genetic isolates who settled in North America in 1874. Descended from <100 founders, they trace their origins to 16th-century Europe.
Methods and Results—
We clinically and genetically evaluated 2 large families of the Alberta Hutterite population with a history of sudden death and found several individuals with severe forms of biventricular cardiomyopathy characterized by mainly left-sided localized aneurysms, regions of wall thinning with segmental akinesis, in addition to typical electric and histological features known for arrhythmogenic right ventricular cardiomyopathy. We identified a homozygous truncation mutation, c.1660C>T (p.Q554X) in desmocollin-2 (
DSC2
), in affected individuals and determined a carrier frequency of this mutation of 9.4% (1 in 10.6) among 1535 Schmiedeleut Hutterites, suggesting a common founder in that subgroup. Immunohistochemistry of endomyocardial biopsy samples revealed altered expression of the truncated DSC2 protein at the intercalated discs but only minor changes in immunoreactivity of other desmosomal proteins. Recombinant expressed mutant DSC2 protein in cells confirmed a stable, partially processed truncated protein with cytoplasmic and membrane localization.
Conclusions—
A homozygous truncation mutation in
DSC2
leads to a cardiac-restricted phenotype of an early onset biventricular arrhythmogenic cardiomyopathy. The truncated protein remains partially stable and localized at the intercalated discs. These data suggest that the processed DSC2 protein plays a role in maintaining desmosome integrity and function.
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Affiliation(s)
- Brenda Gerull
- From the Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (B.G., K.C., O.S., H.J.D.), and Department of Medical Genetics (B.G., J.T.), University of Calgary, Calgary, AB, Canada; Max Delbrück Center for Molecular Medicine, Berlin, Germany (F.K.); Department of Human Genetics, The University of Chicago, Chicago, IL (J.X.C., D.W., C.O.); and Centre for Cardiology, Baden-Baden, Germany (O.S.)
| | - Florian Kirchner
- From the Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (B.G., K.C., O.S., H.J.D.), and Department of Medical Genetics (B.G., J.T.), University of Calgary, Calgary, AB, Canada; Max Delbrück Center for Molecular Medicine, Berlin, Germany (F.K.); Department of Human Genetics, The University of Chicago, Chicago, IL (J.X.C., D.W., C.O.); and Centre for Cardiology, Baden-Baden, Germany (O.S.)
| | - Jessica X. Chong
- From the Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (B.G., K.C., O.S., H.J.D.), and Department of Medical Genetics (B.G., J.T.), University of Calgary, Calgary, AB, Canada; Max Delbrück Center for Molecular Medicine, Berlin, Germany (F.K.); Department of Human Genetics, The University of Chicago, Chicago, IL (J.X.C., D.W., C.O.); and Centre for Cardiology, Baden-Baden, Germany (O.S.)
| | - Julia Tagoe
- From the Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (B.G., K.C., O.S., H.J.D.), and Department of Medical Genetics (B.G., J.T.), University of Calgary, Calgary, AB, Canada; Max Delbrück Center for Molecular Medicine, Berlin, Germany (F.K.); Department of Human Genetics, The University of Chicago, Chicago, IL (J.X.C., D.W., C.O.); and Centre for Cardiology, Baden-Baden, Germany (O.S.)
| | - Kumaran Chandrasekharan
- From the Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (B.G., K.C., O.S., H.J.D.), and Department of Medical Genetics (B.G., J.T.), University of Calgary, Calgary, AB, Canada; Max Delbrück Center for Molecular Medicine, Berlin, Germany (F.K.); Department of Human Genetics, The University of Chicago, Chicago, IL (J.X.C., D.W., C.O.); and Centre for Cardiology, Baden-Baden, Germany (O.S.)
| | - Oliver Strohm
- From the Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (B.G., K.C., O.S., H.J.D.), and Department of Medical Genetics (B.G., J.T.), University of Calgary, Calgary, AB, Canada; Max Delbrück Center for Molecular Medicine, Berlin, Germany (F.K.); Department of Human Genetics, The University of Chicago, Chicago, IL (J.X.C., D.W., C.O.); and Centre for Cardiology, Baden-Baden, Germany (O.S.)
| | - Darrel Waggoner
- From the Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (B.G., K.C., O.S., H.J.D.), and Department of Medical Genetics (B.G., J.T.), University of Calgary, Calgary, AB, Canada; Max Delbrück Center for Molecular Medicine, Berlin, Germany (F.K.); Department of Human Genetics, The University of Chicago, Chicago, IL (J.X.C., D.W., C.O.); and Centre for Cardiology, Baden-Baden, Germany (O.S.)
| | - Carole Ober
- From the Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (B.G., K.C., O.S., H.J.D.), and Department of Medical Genetics (B.G., J.T.), University of Calgary, Calgary, AB, Canada; Max Delbrück Center for Molecular Medicine, Berlin, Germany (F.K.); Department of Human Genetics, The University of Chicago, Chicago, IL (J.X.C., D.W., C.O.); and Centre for Cardiology, Baden-Baden, Germany (O.S.)
| | - Henry J. Duff
- From the Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta (B.G., K.C., O.S., H.J.D.), and Department of Medical Genetics (B.G., J.T.), University of Calgary, Calgary, AB, Canada; Max Delbrück Center for Molecular Medicine, Berlin, Germany (F.K.); Department of Human Genetics, The University of Chicago, Chicago, IL (J.X.C., D.W., C.O.); and Centre for Cardiology, Baden-Baden, Germany (O.S.)
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Bai Y, Jones PP, Guo J, Zhong X, Clark RB, Zhou Q, Wang R, Vallmitjana A, Benitez R, Hove-Madsen L, Semeniuk L, Guo A, Song LS, Duff HJ, Chen SRW. Phospholamban knockout breaks arrhythmogenic Ca²⁺ waves and suppresses catecholaminergic polymorphic ventricular tachycardia in mice. Circ Res 2013; 113:517-26. [PMID: 23856523 DOI: 10.1161/circresaha.113.301678] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
RATIONALE Phospholamban (PLN) is an inhibitor of cardiac sarco(endo)plasmic reticulum Ca²⁺ ATPase. PLN knockout (PLN-KO) enhances sarcoplasmic reticulum Ca²⁺ load and Ca²⁺ leak. Conversely, PLN-KO accelerates Ca²⁺ sequestration and aborts arrhythmogenic spontaneous Ca²⁺ waves (SCWs). An important question is whether these seemingly paradoxical effects of PLN-KO exacerbate or protect against Ca²⁺-triggered arrhythmias. OBJECTIVE We investigate the impact of PLN-KO on SCWs, triggered activities, and stress-induced ventricular tachyarrhythmias (VTs) in a mouse model of cardiac ryanodine-receptor (RyR2)-linked catecholaminergic polymorphic VT. METHODS AND RESULTS We generated a PLN-deficient, RyR2-mutant mouse model (PLN-/-/RyR2-R4496C+/-) by crossbreeding PLN-KO mice with catecholaminergic polymorphic VT-associated RyR2-R4496C mutant mice. Ca²⁺ imaging and patch-clamp recording revealed cell-wide propagating SCWs and triggered activities in RyR2-R4496C+/- ventricular myocytes during sarcoplasmic reticulum Ca²⁺ overload. PLN-KO fragmented these cell-wide SCWs into mini-waves and Ca²⁺ sparks and suppressed the triggered activities evoked by sarcoplasmic reticulum Ca²⁺ overload. Importantly, these effects of PLN-KO were reverted by partially inhibiting sarco(endo)plasmic reticulum Ca²⁺ ATPase with 2,5-di-tert-butylhydroquinone. However, Bay K, caffeine, or Li⁺ failed to convert mini-waves to cell-wide SCWs in PLN-/-/RyR2-R4496C+/- ventricular myocytes. Furthermore, ECG analysis showed that PLN-KO mice are not susceptible to stress-induced VTs. On the contrary, PLN-KO protected RyR2-R4496C mutant mice from stress-induced VTs. CONCLUSIONS Our results demonstrate that despite severe sarcoplasmic reticulum Ca²⁺ leak, PLN-KO suppresses triggered activities and stress-induced VTs in a mouse model of catecholaminergic polymorphic VT. These data suggest that breaking up cell-wide propagating SCWs by enhancing Ca²⁺ sequestration represents an effective approach for suppressing Ca²⁺-triggered arrhythmias.
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Affiliation(s)
- Yunlong Bai
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
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43
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Bracey NA, Beck PL, Muruve DA, Hirota SA, Guo J, Jabagi H, Wright Jr JR, MacDonald JA, Lees-Miller JP, Roach D, Semeniuk LM, Duff HJ. The Nlrp3 inflammasome promotes myocardial dysfunction in structural cardiomyopathy through interleukin-1β. Exp Physiol 2013; 98:462-72. [DOI: 10.1113/expphysiol.2012.068338] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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44
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Abstract
BACKGROUND Risk assessment studies use a suite of nominally independent noninvasive heart rate metrics, often brought together in a statistical model to compute a risk score. The ongoing need to noninvasively identify the higher risk patients requiring more invasive investigations/interventions drives the search for better noninvasive predictive metrics, with increased sensitivity. Many varieties of autoregulatory malfunction occur within the cardiovascular system; thus, it seems a daunting challenge to build predictive models that account for all potential modes of failure. Auto-entrainment (AE) methodology was developed to help address this challenge. METHODS AND RESULTS AE methodology tests intrinsic capacity to maintain a stable and coherent oscillatory dynamic of autoregulatory control via respiratory entrainment of the blood pressure and heart period. Using cardiovascular death (n=18) at follow-up (1.5 years) as the end point, analysis of AE measurements from 148 patients with heart failure revealed 2 parameters significantly predictive of death. Using logistic regression, the magnitude of systolic pulsus alternans measured during AE had predictive sensitivity of 90% (confidence interval, 62%-100% and specificity of 62% (confidence interval, 49%-74%). The capacity to maintain a stable oscillatory dynamic was measured by the fraction of the total RR-interval spectral power contained within the AE-band. This capacity had predictive sensitivity of 73% (confidence interval, 47%-99%) and specificity of 55% (confidence interval, 43%-66%). CONCLUSIONS AE methodology provides a noninvasive platform to assess the integrity of cardiovascular autoregulatory control systems for risk assessment in heart failure patients.
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Affiliation(s)
- Daniel E Roach
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
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45
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Wang W, Wang X, Chun J, Vilaysane A, Clark S, French G, Bracey NA, Trpkov K, Bonni S, Duff HJ, Beck PL, Muruve DA. Inflammasome-independent NLRP3 augments TGF-β signaling in kidney epithelium. J Immunol 2012; 190:1239-49. [PMID: 23264657 DOI: 10.4049/jimmunol.1201959] [Citation(s) in RCA: 188] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Tubulointerstitial inflammation and fibrosis are strongly associated with the outcome of chronic kidney disease. We recently demonstrated that the NOD-like receptor, pyrin domain containing-3 (NLRP3) contributes to renal inflammation, injury, and fibrosis following unilateral ureteric obstruction in mice. NLRP3 expression in renal tubular epithelial cells (TECs) was found to be an important component of experimental disease pathogenesis, although the biology of NLRP3 in epithelial cells is unknown. In human and mouse primary renal TECs, NLRP3 expression was increased in response to TGF-β1 stimulation and associated with epithelial-mesenchymal transition (EMT) and the expression of α-smooth muscle actin (αSMA) and matrix metalloproteinase (MMP) 9. TGF-β1-induced EMT and the induction of MMP-9 and αSMA were significantly decreased in mouse Nlrp3(-/-) renal TECs, suggesting a role for Nlrp3 in TGF-β-dependent signaling. Although apoptosis-associated speck-like protein containing a CARD domain(-/-) TECs demonstrated a phenotype similar to that of Nlrp3(-/-) cells in response to TGF-β1, the effect of Nlrp3 on MMP-9 and αSMA expression was inflammasome independent, as IL-1β, IL-18, MyD88, and caspase-1 were dispensable. Smad2 and Smad3 phosphorylation in response to TGF-β1 was attenuated in Nlrp3(-/-) and apoptosis-associated speck-like protein containing a CARD domain(-/-) cells, accounting for the dampened EMT and TGF-β1 responsiveness in these cells. Consistent with these findings, overexpression of NLRP3 in 293T cells resulted in increased Smad3 phosphorylation and activity. Taken together, these data support a novel and direct role for NLRP3 in promoting TGF-β signaling and R-Smad activation in epithelial cells independent of the inflammasome.
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Affiliation(s)
- Wenjie Wang
- Department of Medicine, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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Durdagi S, Deshpande S, Duff HJ, Noskov SY. Modeling of open, closed, and open-inactivated states of the hERG1 channel: structural mechanisms of the state-dependent drug binding. J Chem Inf Model 2012; 52:2760-74. [PMID: 22989185 DOI: 10.1021/ci300353u] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The human ether-a-go-go related gene 1 (hERG1) K ion channel is a key element for the rapid component of the delayed rectified potassium current in cardiac myocytes. Since there are no crystal structures for hERG channels, creation and validation of its reliable atomistic models have been key targets in molecular cardiology for the past decade. In this study, we developed and vigorously validated models for open, closed, and open-inactivated states of hERG1 using a multistep protocol. The conserved elements were derived using multiple-template homology modeling utilizing available structures for Kv1.2, Kv1.2/2.1 chimera, and KcsA channels. Then missing elements were modeled with the ROSETTA De Novo protein-designing suite and further refined with all-atom molecular dynamics simulations. The final ensemble of models was evaluated for consistency to the reported experimental data from biochemical, biophysical, and electrophysiological studies. The closed state models were cross-validated against available experimental data on toxin footprinting with protein-protein docking using hERG state-selective toxin BeKm-1. Poisson-Boltzmann calculations were performed to determine gating charge and compare it to electrophysiological measurements. The validated structures offered us a unique chance to assess molecular mechanisms of state-dependent drug binding in three different states of the channel.
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Affiliation(s)
- Serdar Durdagi
- Institute for Biocomplexity and Informatics, Department of Biological Sciences, University of Calgary, Alberta, Canada
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Durdagi S, Guo J, Lees-Miller JP, Noskov SY, Duff HJ. Structure-guided topographic mapping and mutagenesis to elucidate binding sites for the human ether-a-go-go-related gene 1 potassium channel (KCNH2) activator NS1643. J Pharmacol Exp Ther 2012; 342:441-52. [PMID: 22573844 DOI: 10.1124/jpet.111.189159] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Loss-of -function mutations in human ether-a-go-go-related gene 1 (hERG1) is associated with life-threatening arrhythmias. hERG1 activators are being developed as treatments for acquired or genetic forms of long QT syndrome. The locations of the putative binding pockets for activators are still being elucidated. In silico docking of the activator 1,3-bis-(2-hydroxy-5-trifluoromethylphenyl)-urea (NS1643) to an S1-S6 transmembrane homology model of hERG1 predicted putative binding sites. The predictions of the in silico docking guided subsequent in vitro mutagenesis and electrophysiological measurements. The novel interacting site for NS1643 is predicted around Asn629 at the outer mouth of the channel. The applied N629H mutation is the sole amino acid replacement in the literature that abrogates the NS1643-induced left shift of the V(1/2) of activation. In contrast, both N629T and N629D showed pharmacologic responses similar to wild type. Another important interacting pocket is predicted at the intracellular surface in the S4-S5 linker. Mutagenesis of the residues critical to interactions in this pocket had major effects on the pharmacologic response to NS1643. The inward conductance elicited by hyperpolarization of D540K hERG1 was abrogated by NS1643 treatment, suggesting that it alters the inward movement of the S4 segment. The neighboring E544L mutation markedly exaggerated tail-current responses to NS1643. However, an L564A substitution inhibited drug response. Structure-guided mutagenesis identified widespread clusters of amino acids modulating drug-induced shifts in inactivation; such modulation may reflect allosteric changes in tertiary structure. Model-guided mutagenesis led to the discovery of a range of novel interacting residues that modify NS1643-induced pharmacologic responses.
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Affiliation(s)
- Serdar Durdagi
- Institute for Biocomplexity and Informatics, Department of Biological Sciences, University of Calgary, Calgary, Canada
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Abstract
Background—
Experimental cell therapy attenuates maladaptive cardiac remodeling and improves heart function. Paracrine mechanisms have been proposed. The effect of cell therapy on post infarction cardiac fibroblast and extracellular matrix (ECM) regulation was examined.
Methods and Results—
Vascular smooth muscle cells (VSMC) were injected into the border zone of subacute infarcted syngeneic Fischer rat hearts and compared with medium-injected controls. Twelve weeks post injection, cell-treated hearts showed preserved ECM content and attenuated structural chamber remodeling. Myofibroblast activation (α-smooth muscle actin expression) was decreased significantly, while basic fibroblast growth factor (bFGF) expression, a known inhibitor of transforming growth factor β-1–induced fibroblast differentiation, was increased. Matrix metalloproteinase-2 expression and activation by gelatin zymography was unchanged between groups, while its endogenous inhibitor, tissue inhibitors of matrix metalloproteinase (TIMP)-2, showed both increased expression and enhanced inhibitory capacity in cell-treated hearts. To define paracrine mechanisms, in vitro effects of VSMC conditioned media on myofibroblast activation were assessed by 3-D collagen gel contraction assay. VSMC conditioned media significantly inhibited collagen contraction, while a specific bFGF inhibitor abolished this paracrine response. TIMP-2 induced collagen contraction, but the effect was suppressed in the presence of bFGF.
Conclusions—
Extracellular matrix dysregulation post myocardial infarction is improved by cell therapy. These data suggest that cell transplantation attenuates myofibroblast activation and subsequent maladaptive structural chamber remodeling through paracrine mechanisms involving bFGF and TIMP-2.
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Affiliation(s)
- Paul W.M. Fedak
- From the Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Alberta, Canada. Liping Bai was affiliated with Libin Cardiovascular Institute of Alberta at the time that this work was completed
| | - Liping Bai
- From the Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Alberta, Canada. Liping Bai was affiliated with Libin Cardiovascular Institute of Alberta at the time that this work was completed
| | - Jeannine Turnbull
- From the Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Alberta, Canada. Liping Bai was affiliated with Libin Cardiovascular Institute of Alberta at the time that this work was completed
| | - Janet Ngu
- From the Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Alberta, Canada. Liping Bai was affiliated with Libin Cardiovascular Institute of Alberta at the time that this work was completed
| | - Kishan Narine
- From the Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Alberta, Canada. Liping Bai was affiliated with Libin Cardiovascular Institute of Alberta at the time that this work was completed
| | - Henry J. Duff
- From the Department of Cardiac Sciences, University of Calgary, Libin Cardiovascular Institute of Alberta, Alberta, Canada. Liping Bai was affiliated with Libin Cardiovascular Institute of Alberta at the time that this work was completed
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Shafa M, Krawetz R, Zhang Y, Rattner JB, Godollei A, Duff HJ, Rancourt DE. Impact of stirred suspension bioreactor culture on the differentiation of murine embryonic stem cells into cardiomyocytes. BMC Cell Biol 2011; 12:53. [PMID: 22168552 PMCID: PMC3260255 DOI: 10.1186/1471-2121-12-53] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 12/14/2011] [Indexed: 12/11/2022] Open
Abstract
Background Embryonic stem cells (ESCs) can proliferate endlessly and are able to differentiate into all cell lineages that make up the adult organism. Under particular in vitro culture conditions, ESCs can be expanded and induced to differentiate into cardiomyocytes in stirred suspension bioreactors (SSBs). However, in using these systems we must be cognizant of the mechanical forces acting upon the cells. The effect of mechanical forces and shear stress on ESC pluripotency and differentiation has yet to be clarified. The purpose of this study was to investigate the impact of the suspension culture environment on ESC pluripotency during cardiomyocyte differentiation. Results Murine D3-MHC-neor ESCs formed embyroid bodies (EBs) and differentiated into cardiomyocytes over 25 days in static culture and suspension bioreactors. G418 (Geneticin) was used in both systems from day 10 to enrich for cardiomyocytes by eliminating non-resistant, undifferentiated cells. Treatment of EBs with 1 mM ascorbic acid and 0.5% dimethyl sulfoxide from day 3 markedly increased the number of beating EBs, which displayed spontaneous and cadenced contractile beating on day 11 in the bioreactor. Our results showed that the bioreactor differentiated cells displayed the characteristics of fully functional cardiomyocytes. Remarkably, however, our results demonstrated that the bioreactor differentiated ESCs retained their ability to express pluripotency markers, to form ESC-like colonies, and to generate teratomas upon transplantation, whereas the cells differentiated in adherent culture lost these characteristics. Conclusions This study demonstrates that although cardiomyocyte differentiation can be achieved in stirred suspension bioreactors, the addition of medium enhancers is not adequate to force complete differentiation as fluid shear forces appear to maintain a subpopulation of cells in a transient pluripotent state. The development of successful ESC differentiation protocols within suspension bioreactors demands a more complete understanding of the impacts of shear forces on the regulation of pluripotency and differentiation in pluripotent stem cells.
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Affiliation(s)
- Mehdi Shafa
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, AB, Canada
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Zhou Q, Xiao J, Jiang D, Wang R, Vembaiyan K, Wang A, Smith CD, Xie C, Chen W, Zhang J, Tian X, Jones PP, Zhong X, Guo A, Chen H, Zhang L, Zhu W, Yang D, Li X, Chen J, Gillis AM, Duff HJ, Cheng H, Feldman AM, Song LS, Fill M, Back TG, Chen SRW. Carvedilol and its new analogs suppress arrhythmogenic store overload-induced Ca2+ release. Nat Med 2011; 17:1003-9. [PMID: 21743453 DOI: 10.1038/nm.2406] [Citation(s) in RCA: 185] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 05/23/2011] [Indexed: 12/31/2022]
Abstract
Carvedilol is one of the most effective beta blockers for preventing ventricular tachyarrhythmias in heart failure, but the mechanisms underlying its favorable antiarrhythmic benefits remain unclear. Spontaneous Ca(2+) waves, also called store overload-induced Ca(2+) release (SOICR), evoke ventricular tachyarrhythmias in individuals with heart failure. Here we show that carvedilol is the only beta blocker tested that effectively suppresses SOICR by directly reducing the open duration of the cardiac ryanodine receptor (RyR2). This unique anti-SOICR activity of carvedilol, combined with its beta-blocking activity, probably contributes to its favorable antiarrhythmic effect. To enable optimal titration of carvedilol's actions as a beta blocker and as a suppressor of SOICR separately, we developed a new SOICR-inhibiting, minimally beta-blocking carvedilol analog, VK-II-86. VK-II-86 prevented stress-induced ventricular tachyarrhythmias in RyR2-mutant mice and did so more effectively when combined with either of the selective beta blockers metoprolol or bisoprolol. Combining SOICR inhibition with optimal beta blockade has the potential to provide antiarrhythmic therapy that can be tailored to individual patients.
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Affiliation(s)
- Qiang Zhou
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
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