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Trum M, Riechel J, Schollmeier E, Lebek S, Hegner P, Reuthner K, Heers S, Keller K, Wester M, Klatt S, Hamdani N, Provaznik Z, Schmid C, Maier L, Arzt M, Wagner S. Empagliflozin inhibits increased Na influx in atrial cardiomyocytes of patients with HFpEF. Cardiovasc Res 2024; 120:999-1010. [PMID: 38728438 PMCID: PMC11288740 DOI: 10.1093/cvr/cvae095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/16/2024] [Accepted: 02/02/2024] [Indexed: 05/12/2024] Open
Abstract
AIMS Heart failure with preserved ejection fraction (HFpEF) causes substantial morbidity and mortality. Importantly, atrial remodelling and atrial fibrillation are frequently observed in HFpEF. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have recently been shown to improve clinical outcomes in HFpEF, and post-hoc analyses suggest atrial anti-arrhythmic effects. We tested if isolated human atrial cardiomyocytes from patients with HFpEF exhibit an increased Na influx, which is known to cause atrial arrhythmias, and if that is responsive to treatment with the SGTL2i empagliflozin. METHODS AND RESULTS Cardiomyocytes were isolated from atrial biopsies of 124 patients (82 with HFpEF) undergoing elective cardiac surgery. Na influx was measured with the Na-dye Asante Natrium Green-2 AM (ANG-2). Compared to patients without heart failure (NF), Na influx was doubled in HFpEF patients (NF vs. HFpEF: 0.21 ± 0.02 vs. 0.38 ± 0.04 mmol/L/min (N = 7 vs. 18); P = 0.0078). Moreover, late INa (measured via whole-cell patch clamp) was significantly increased in HFpEF compared to NF. Western blot and HDAC4 pulldown assay indicated a significant increase in CaMKII expression, CaMKII autophosphorylation, CaMKII activity, and CaMKII-dependent NaV1.5 phosphorylation in HFpEF compared to NF, whereas NaV1.5 protein and mRNA abundance remained unchanged. Consistently, increased Na influx was significantly reduced by treatment not only with the CaMKII inhibitor autocamtide-2-related inhibitory peptide (AIP), late INa inhibitor tetrodotoxin (TTX) but also with sodium/hydrogen exchanger 1 (NHE1) inhibitor cariporide. Importantly, empagliflozin abolished both increased Na influx and late INa in HFpEF. Multivariate linear regression analysis, adjusting for important clinical confounders, revealed HFpEF to be an independent predictor for changes in Na handling in atrial cardiomyocytes. CONCLUSION We show for the first time increased Na influx in human atrial cardiomyocytes from HFpEF patients, partly due to increased late INa and enhanced NHE1-mediated Na influx. Empagliflozin inhibits Na influx and late INa, which could contribute to anti-arrhythmic effects in patients with HFpEF.
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Affiliation(s)
- Maximilian Trum
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Johannes Riechel
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Elisa Schollmeier
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Simon Lebek
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Philipp Hegner
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Kathrin Reuthner
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Silvia Heers
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Karoline Keller
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Michael Wester
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Susanne Klatt
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Nazha Hamdani
- Department of Cellular and Translational Physiology, Ruhr-University Bochum, Bochum, Germany
| | - Zdenek Provaznik
- Department of Cardiothoracic Surgery, University Hospital Regensburg, Regensburg, Germany
| | - Christof Schmid
- Department of Cardiothoracic Surgery, University Hospital Regensburg, Regensburg, Germany
| | - Lars Maier
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Michael Arzt
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Stefan Wagner
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
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2
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Flores PC, Ahmed T, Podgorski J, Ortiz HR, Langlais PR, Mythreye K, Lee NY. Phosphoproteomic profiling identifies DNMT1 as a key substrate of beta IV spectrin-dependent ERK/MAPK signaling in suppressing angiogenesis. Biochem Biophys Res Commun 2024; 711:149916. [PMID: 38613866 PMCID: PMC11089540 DOI: 10.1016/j.bbrc.2024.149916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 04/03/2024] [Accepted: 04/06/2024] [Indexed: 04/15/2024]
Abstract
βIV-spectrin is a membrane-associated cytoskeletal protein that maintains the structural stability of cell membranes and integral proteins such as ion channels and transporters. Its biological functions are best characterized in the brain and heart, although recently we discovered a fundamental new role in the vascular system. Using cellular and genetic mouse models, we reported that βIV-spectrin acts as a critical regulator of developmental and tumor-associated angiogenesis. βIV-spectrin was shown to selectively express in proliferating endothelial cells (EC) and suppress VEGF/VEGFR2 signaling by enhancing receptor internalization and degradation. Here we examined how these events impact the downstream kinase signaling cascades and target substrates. Based on quantitative phosphoproteomics, we found that βIV-spectrin significantly affects the phosphorylation of epigenetic regulatory enzymes in the nucleus, among which DNA methyltransferase 1 (DNMT1) was determined as a top substrate. Biochemical and immunofluorescence results showed that βIV-spectrin inhibits DNMT1 function by activating ERK/MAPK, which in turn phosphorylates DNMT1 at S717 to impede its nuclear localization. Given that DNMT1 controls the DNA methylation patterns genome-wide, and is crucial for vascular development, our findings suggest that epigenetic regulation is a key mechanism by which βIV-spectrin suppresses angiogenesis.
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Affiliation(s)
- Paola Cruz Flores
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ, 85724, USA
| | - Tasmia Ahmed
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ, 85724, USA
| | - Julia Podgorski
- Department of Pharmacology, University of Arizona, Tucson, AZ, 85724, USA
| | - Hannah R Ortiz
- Department of Pharmacology, University of Arizona, Tucson, AZ, 85724, USA
| | - Paul R Langlais
- Department of Medicine, University of Arizona, Tucson, AZ, 85724, USA
| | | | - Nam Y Lee
- Department of Pharmacology, University of Arizona, Tucson, AZ, 85724, USA; Comprehensive Cancer Center, University of Arizona, Tucson, AZ, 85724, USA.
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3
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Pizzo E, Cervantes DO, Ketkar H, Ripa V, Nassal DM, Buck B, Parambath SP, Di Stefano V, Singh K, Thompson CI, Mohler PJ, Hund TJ, Jacobson JT, Jain S, Rota M. Phosphorylation of cardiac sodium channel at Ser571 anticipates manifestations of the aging myopathy. Am J Physiol Heart Circ Physiol 2024; 326:H1424-H1445. [PMID: 38639742 DOI: 10.1152/ajpheart.00325.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 03/12/2024] [Accepted: 04/02/2024] [Indexed: 04/20/2024]
Abstract
Diastolic dysfunction and delayed ventricular repolarization are typically observed in the elderly, but whether these defects are intimately associated with the progressive manifestation of the aging myopathy remains to be determined. In this regard, aging in experimental animals is coupled with increased late Na+ current (INa,L) in cardiomyocytes, raising the possibility that INa,L conditions the modality of electrical recovery and myocardial relaxation of the aged heart. For this purpose, aging male and female wild-type (WT) C57Bl/6 mice were studied together with genetically engineered mice with phosphomimetic (gain of function, GoF) or ablated (loss of function, LoF) mutations of the sodium channel Nav1.5 at Ser571 associated with, respectively, increased and stabilized INa,L. At ∼18 mo of age, WT mice developed prolonged duration of the QT interval of the electrocardiogram and impaired diastolic left ventricular (LV) filling, defects that were reversed by INa,L inhibition. Prolonged repolarization and impaired LV filling occurred prematurely in adult (∼5 mo) GoF mutant mice, whereas these alterations were largely attenuated in aging LoF mutant animals. Ca2+ transient decay and kinetics of myocyte shortening/relengthening were delayed in aged (∼24 mo) WT myocytes, with respect to adult cells. In contrast, delayed Ca2+ transients and contractile dynamics occurred at adult stage in GoF myocytes and further deteriorated in old age. Conversely, myocyte mechanics were minimally affected in aging LoF cells. Collectively, these results document that Nav1.5 phosphorylation at Ser571 and the late Na+ current modulate the modality of myocyte relaxation, constituting the mechanism linking delayed ventricular repolarization and diastolic dysfunction.NEW & NOTEWORTHY We have investigated the impact of the late Na current (INa,L) on cardiac and myocyte function with aging by using genetically engineered animals with enhanced or stabilized INa,L, due to phosphomimetic or phosphoablated mutations of Nav1.5. Our findings support the notion that phosphorylation of Nav1.5 at Ser571 prolongs myocardial repolarization and impairs diastolic function, contributing to the manifestations of the aging myopathy.
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Affiliation(s)
- Emanuele Pizzo
- Department of Physiology, New York Medical College, Valhalla, New York, United States
| | - Daniel O Cervantes
- Department of Physiology, New York Medical College, Valhalla, New York, United States
| | - Harshada Ketkar
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, New York, United States
| | - Valentina Ripa
- Department of Physiology, New York Medical College, Valhalla, New York, United States
| | - Drew M Nassal
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, United States
| | - Benjamin Buck
- Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio, United States
| | - Sreema P Parambath
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, New York, United States
| | - Valeria Di Stefano
- Department of Physiology, New York Medical College, Valhalla, New York, United States
| | - Kanwardeep Singh
- Department of Physiology, New York Medical College, Valhalla, New York, United States
| | - Carl I Thompson
- Department of Physiology, New York Medical College, Valhalla, New York, United States
| | - Peter J Mohler
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
- Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio, United States
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, Ohio, United States
| | - Thomas J Hund
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, United States
- Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio, United States
| | - Jason T Jacobson
- Department of Physiology, New York Medical College, Valhalla, New York, United States
- Department of Cardiology, Westchester Medical Center, Valhalla, New York, United States
| | - Sudhir Jain
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, New York, United States
| | - Marcello Rota
- Department of Physiology, New York Medical College, Valhalla, New York, United States
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Xiang W, Zhou N, Li L, Chen F, Li L, Wang Y. βIV-Spectrin in Cardiac Fibroblasts: Implications for Fibrosis and Therapeutic Targeting in Cardiac Diseases. Comment on Nassal et al. Spectrin-Based Regulation of Cardiac Fibroblast Cell-Cell Communication. Cells 2023, 12, 748. Cells 2023; 12:2186. [PMID: 37681918 PMCID: PMC10486720 DOI: 10.3390/cells12172186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 08/07/2023] [Accepted: 08/29/2023] [Indexed: 09/09/2023] Open
Abstract
Fibroblasts in the heart, traditionally recognized as interstitial cells, have long been overlooked in the study of cardiac physiology and pathology [...].
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Affiliation(s)
- Wenjing Xiang
- Department of Pharmacology, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China (F.C.)
| | - Ning Zhou
- Department of Pharmacology, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China (F.C.)
| | - Lei Li
- School of Public Health, Xi’an Jiaotong University, Xi’an 710061, China;
| | - Faming Chen
- Department of Pharmacology, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China (F.C.)
| | - Lei Li
- Department of Pharmacology, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China (F.C.)
| | - Ying Wang
- Department of Pharmacology, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China (F.C.)
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5
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Ahmed T, Ramonett A, Kwak EA, Kumar S, Flores PC, Ortiz HR, Langlais PR, Hund TJ, Mythreye K, Lee NY. Endothelial tip/stalk cell selection requires BMP9-induced β IV-spectrin expression during sprouting angiogenesis. Mol Biol Cell 2023; 34:ar72. [PMID: 37126382 PMCID: PMC10295478 DOI: 10.1091/mbc.e23-02-0064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/14/2023] [Accepted: 04/19/2023] [Indexed: 05/02/2023] Open
Abstract
βIV-Spectrin is a membrane cytoskeletal protein with specialized roles in the nervous system and heart. Recent evidence also indicates a fundamental role for βIV-spectrin in angiogenesis as its endothelial-specific gene deletion in mice enhances embryonic lethality due to hypervascularization and hemorrhagic defects. During early vascular sprouting, βIV-spectrin is believed to inhibit tip cell sprouting in favor of the stalk cell phenotype by mediating VEGFR2 internalization and degradation. Despite these essential roles, mechanisms governing βIV-spectrin expression remain unknown. Here we identify bone morphogenetic protein 9 (BMP9) as a major inducer of βIV-spectrin gene expression in the vascular system. We show that BMP9 signals through the ALK1/Smad1 pathway to induce βIV-spectrin expression, which then recruits CaMKII to the cell membrane to induce phosphorylation-dependent VEGFR2 turnover. Although BMP9 signaling promotes stalk cell behavior through activation of hallmark stalk cell genes ID-1/3 and Hes-1 and Notch signaling cross-talk, we find that βIV-spectrin acts upstream of these pathways as loss of βIV-spectrin in neonate mice leads to retinal hypervascularization due to excessive VEGFR2 levels, increased tip cell populations, and strong Notch inhibition irrespective of BMP9 treatment. These findings demonstrate βIV-spectrin as a BMP9 gene target critical for tip/stalk cell selection during nascent vessel sprouting.
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Affiliation(s)
- Tasmia Ahmed
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ 85724
| | - Aaron Ramonett
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724
| | - Eun-A Kwak
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724
| | - Sanjay Kumar
- Division of Biology, Indian Institute of Science Education and Research, Tirupati 517507, India
| | - Paola Cruz Flores
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ 85724
| | - Hannah R. Ortiz
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724
| | | | - Thomas J. Hund
- Department of Biomedical Engineering, Ohio State University, Columbus, OH 43210
| | - Karthikeyan Mythreye
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Nam Y. Lee
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ 85724
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724
- Comprehensive Cancer Center, University of Arizona, Tucson, AZ 85724
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6
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Lorenzo DN, Edwards RJ, Slavutsky AL. Spectrins: molecular organizers and targets of neurological disorders. Nat Rev Neurosci 2023; 24:195-212. [PMID: 36697767 PMCID: PMC10598481 DOI: 10.1038/s41583-022-00674-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2022] [Indexed: 01/26/2023]
Abstract
Spectrins are cytoskeletal proteins that are expressed ubiquitously in the mammalian nervous system. Pathogenic variants in SPTAN1, SPTBN1, SPTBN2 and SPTBN4, four of the six genes encoding neuronal spectrins, cause neurological disorders. Despite their structural similarity and shared role as molecular organizers at the cell membrane, spectrins vary in expression, subcellular localization and specialization in neurons, and this variation partly underlies non-overlapping disease presentations across spectrinopathies. Here, we summarize recent progress in discerning the local and long-range organization and diverse functions of neuronal spectrins. We provide an overview of functional studies using mouse models, which, together with growing human genetic and clinical data, are helping to illuminate the aetiology of neurological spectrinopathies. These approaches are all critical on the path to plausible therapeutic solutions.
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Affiliation(s)
- Damaris N Lorenzo
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Reginald J Edwards
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Anastasia L Slavutsky
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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7
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Li E, Kool W, Woolschot L, van der Heyden MAG. Chronic Propafenone Application Increases Functional K IR2.1 Expression In Vitro. Pharmaceuticals (Basel) 2023; 16:ph16030404. [PMID: 36986503 PMCID: PMC10056987 DOI: 10.3390/ph16030404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 02/28/2023] [Accepted: 03/04/2023] [Indexed: 03/30/2023] Open
Abstract
Expression and activity of inwardly rectifying potassium (KIR) channels within the heart are strictly regulated. KIR channels have an important role in shaping cardiac action potentials, having a limited conductance at depolarized potentials but contributing to the final stage of repolarization and resting membrane stability. Impaired KIR2.1 function causes Andersen-Tawil Syndrome (ATS) and is associated with heart failure. Restoring KIR2.1 function by agonists of KIR2.1 (AgoKirs) would be beneficial. The class 1c antiarrhythmic drug propafenone is identified as an AgoKir; however, its long-term effects on KIR2.1 protein expression, subcellular localization, and function are unknown. Propafenone's long-term effect on KIR2.1 expression and its underlying mechanisms in vitro were investigated. KIR2.1-carried currents were measured by single-cell patch-clamp electrophysiology. KIR2.1 protein expression levels were determined by Western blot analysis, whereas conventional immunofluorescence and advanced live-imaging microscopy were used to assess the subcellular localization of KIR2.1 proteins. Acute propafenone treatment at low concentrations supports the ability of propafenone to function as an AgoKir without disturbing KIR2.1 protein handling. Chronic propafenone treatment (at 25-100 times higher concentrations than in the acute treatment) increases KIR2.1 protein expression and KIR2.1 current densities in vitro, which are potentially associated with pre-lysosomal trafficking inhibition.
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Affiliation(s)
- Encan Li
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Willy Kool
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Liset Woolschot
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
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Song I, Kuznetsova T, Baidoe-Ansah D, Mirzapourdelavar H, Senkov O, Hayani H, Mironov A, Kaushik R, Druzin M, Johansson S, Dityatev A. Heparan Sulfates Regulate Axonal Excitability and Context Generalization through Ca 2+/Calmodulin-Dependent Protein Kinase II. Cells 2023; 12:cells12050744. [PMID: 36899880 PMCID: PMC10000602 DOI: 10.3390/cells12050744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 03/03/2023] Open
Abstract
Our previous studies demonstrated that enzymatic removal of highly sulfated heparan sulfates with heparinase 1 impaired axonal excitability and reduced expression of ankyrin G at the axon initial segments in the CA1 region of the hippocampus ex vivo, impaired context discrimination in vivo, and increased Ca2+/calmodulin-dependent protein kinase II (CaMKII) activity in vitro. Here, we show that in vivo delivery of heparinase 1 in the CA1 region of the hippocampus elevated autophosphorylation of CaMKII 24 h after injection in mice. Patch clamp recording in CA1 neurons revealed no significant heparinase effects on the amplitude or frequency of miniature excitatory and inhibitory postsynaptic currents, while the threshold for action potential generation was increased and fewer spikes were generated in response to current injection. Delivery of heparinase on the next day after contextual fear conditioning induced context overgeneralization 24 h after injection. Co-administration of heparinase with the CaMKII inhibitor (autocamtide-2-related inhibitory peptide) rescued neuronal excitability and expression of ankyrin G at the axon initial segment. It also restored context discrimination, suggesting the key role of CaMKII in neuronal signaling downstream of heparan sulfate proteoglycans and highlighting a link between impaired CA1 pyramidal cell excitability and context generalization during recall of contextual memories.
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Affiliation(s)
- Inseon Song
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
| | - Tatiana Kuznetsova
- Department of Integrative Medical Biology, Umeå University, 90187 Umeå, Sweden
| | - David Baidoe-Ansah
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
| | - Hadi Mirzapourdelavar
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
| | - Oleg Senkov
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
| | - Hussam Hayani
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
| | - Andrey Mironov
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
| | - Rahul Kaushik
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
| | - Michael Druzin
- Department of Integrative Medical Biology, Umeå University, 90187 Umeå, Sweden
| | - Staffan Johansson
- Department of Integrative Medical Biology, Umeå University, 90187 Umeå, Sweden
| | - Alexander Dityatev
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
- Medizinische Fakultät, Otto-von-Güricke-Universität Magdeburg, 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), 39106 Magdeburg, Germany
- Correspondence: ; Tel.: +49-391-67-24526; Fax: +49-391-6724530
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Crespo-García T, Cámara-Checa A, Dago M, Rubio-Alarcón M, Rapún J, Tamargo J, Delpón E, Caballero R. Regulation of cardiac ion channels by transcription factors: Looking for new opportunities of druggable targets for the treatment of arrhythmias. Biochem Pharmacol 2022; 204:115206. [PMID: 35963339 DOI: 10.1016/j.bcp.2022.115206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/04/2022] [Accepted: 08/05/2022] [Indexed: 11/29/2022]
Abstract
Cardiac electrical activity is governed by different ion channels that generate action potentials. Acquired or inherited abnormalities in the expression and/or function of ion channels usually result in electrophysiological changes that can cause cardiac arrhythmias. Transcription factors (TFs) control gene transcription by binding to specific DNA sequences adjacent to target genes. Linkage analysis, candidate-gene screening within families, and genome-wide association studies have linked rare and common genetic variants in the genes encoding TFs with genetically-determined cardiac arrhythmias. Besides its critical role in cardiac development, recent data demonstrated that they control cardiac electrical activity through the direct regulation of the expression and function of cardiac ion channels in adult hearts. This narrative review summarizes some studies showing functional data on regulation of the main human atrial and ventricular Na+, Ca2+, and K+ channels by cardiac TFs such as Pitx2c, Tbx20, Tbx5, Zfhx3, among others. The results have improved our understanding of the mechanisms regulating cardiac electrical activity and may open new avenues for therapeutic interventions in cardiac acquired or inherited arrhythmias through the identification of TFs as potential drug targets. Even though TFs have for a long time been considered as 'undruggable' targets, advances in structural biology have led to the identification of unique pockets in TFs amenable to be targeted with small-molecule drugs or peptides that are emerging as novel therapeutic drugs.
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Affiliation(s)
- T Crespo-García
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
| | - A Cámara-Checa
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
| | - M Dago
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
| | - M Rubio-Alarcón
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
| | - J Rapún
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
| | - J Tamargo
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
| | - E Delpón
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain.
| | - R Caballero
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
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- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón. CIBERCV, 28040 Madrid, Spain
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10
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Yang HQ, Echeverry FA, ElSheikh A, Gando I, Anez Arredondo S, Samper N, Cardozo T, Delmar M, Shyng SL, Coetzee WA. Subcellular trafficking and endocytic recycling of K ATP channels. Am J Physiol Cell Physiol 2022; 322:C1230-C1247. [PMID: 35508187 PMCID: PMC9169827 DOI: 10.1152/ajpcell.00099.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/27/2022] [Accepted: 04/30/2022] [Indexed: 11/22/2022]
Abstract
Sarcolemmal/plasmalemmal ATP-sensitive K+ (KATP) channels have key roles in many cell types and tissues. Hundreds of studies have described how the KATP channel activity and ATP sensitivity can be regulated by changes in the cellular metabolic state, by receptor signaling pathways and by pharmacological interventions. These alterations in channel activity directly translate to alterations in cell or tissue function, that can range from modulating secretory responses, such as insulin release from pancreatic β-cells or neurotransmitters from neurons, to modulating contractile behavior of smooth muscle or cardiac cells to elicit alterations in blood flow or cardiac contractility. It is increasingly becoming apparent, however, that KATP channels are regulated beyond changes in their activity. Recent studies have highlighted that KATP channel surface expression is a tightly regulated process with similar implications in health and disease. The surface expression of KATP channels is finely balanced by several trafficking steps including synthesis, assembly, anterograde trafficking, membrane anchoring, endocytosis, endocytic recycling, and degradation. This review aims to summarize the physiological and pathophysiological implications of KATP channel trafficking and mechanisms that regulate KATP channel trafficking. A better understanding of this topic has potential to identify new approaches to develop therapeutically useful drugs to treat KATP channel-related diseases.
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Affiliation(s)
- Hua-Qian Yang
- Cyrus Tang Hematology Center, Soochow University, Suzhou, People's Republic of China
| | | | - Assmaa ElSheikh
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon
- Department of Medical Biochemistry, Tanta University, Tanta, Egypt
| | - Ivan Gando
- Department of Pathology, NYU School of Medicine, New York, New York
| | | | - Natalie Samper
- Department of Pathology, NYU School of Medicine, New York, New York
| | - Timothy Cardozo
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
| | - Mario Delmar
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
- Department of Medicine, NYU School of Medicine, New York, New York
| | - Show-Ling Shyng
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon
| | - William A Coetzee
- Department of Pathology, NYU School of Medicine, New York, New York
- Department of Neuroscience & Physiology, NYU School of Medicine, New York, New York
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
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11
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βIV-spectrin as a stalk cell-intrinsic regulator of VEGF signaling. Nat Commun 2022; 13:1326. [PMID: 35288568 PMCID: PMC8921520 DOI: 10.1038/s41467-022-28933-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 02/14/2022] [Indexed: 11/25/2022] Open
Abstract
Defective angiogenesis underlies over 50 malignant, ischemic and inflammatory disorders yet long-term therapeutic applications inevitably fail, thus highlighting the need for greater understanding of the vast crosstalk and compensatory mechanisms. Based on proteomic profiling of angiogenic endothelial components, here we report βIV-spectrin, a non-erythrocytic cytoskeletal protein, as a critical regulator of sprouting angiogenesis. Early loss of endothelial-specific βIV-spectrin promotes embryonic lethality in mice due to hypervascularization and hemorrhagic defects whereas neonatal depletion yields higher vascular density and tip cell populations in developing retina. During sprouting, βIV-spectrin expresses in stalk cells to inhibit their tip cell potential by enhancing VEGFR2 turnover in a manner independent of most cell-fate determining mechanisms. Rather, βIV-spectrin recruits CaMKII to the plasma membrane to directly phosphorylate VEGFR2 at Ser984, a previously undefined phosphoregulatory site that strongly induces VEGFR2 internalization and degradation. These findings support a distinct spectrin-based mechanism of tip-stalk cell specification during vascular development. Defective angiogenesis remains a high source of morbidity in multiple disorders. Here they show that βIV-spectrin, a membrane-associated cytoskeletal protein, is essential for regulation of endothelial tip cell populations and VEGF signaling during sprouting angiogenesis.
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12
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Daimi H, Lozano-Velasco E, Aranega A, Franco D. Genomic and Non-Genomic Regulatory Mechanisms of the Cardiac Sodium Channel in Cardiac Arrhythmias. Int J Mol Sci 2022; 23:1381. [PMID: 35163304 PMCID: PMC8835759 DOI: 10.3390/ijms23031381] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 12/30/2021] [Accepted: 01/06/2022] [Indexed: 12/19/2022] Open
Abstract
Nav1.5 is the predominant cardiac sodium channel subtype, encoded by the SCN5A gene, which is involved in the initiation and conduction of action potentials throughout the heart. Along its biosynthesis process, Nav1.5 undergoes strict genomic and non-genomic regulatory and quality control steps that allow only newly synthesized channels to reach their final membrane destination and carry out their electrophysiological role. These regulatory pathways are ensured by distinct interacting proteins that accompany the nascent Nav1.5 protein along with different subcellular organelles. Defects on a large number of these pathways have a tremendous impact on Nav1.5 functionality and are thus intimately linked to cardiac arrhythmias. In the present review, we provide current state-of-the-art information on the molecular events that regulate SCN5A/Nav1.5 and the cardiac channelopathies associated with defects in these pathways.
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Affiliation(s)
- Houria Daimi
- Biochemistry and Molecular Biology Laboratory, Faculty of Pharmacy, University of Monastir, Monastir 5000, Tunisia
| | - Estefanía Lozano-Velasco
- Department of Experimental Biology, University of Jaen, 23071 Jaen, Spain; (E.L.-V.); (A.A.); (D.F.)
- Medina Foundation, Technology Park of Health Sciences, Av. del Conocimiento, 34, 18016 Granada, Spain
| | - Amelia Aranega
- Department of Experimental Biology, University of Jaen, 23071 Jaen, Spain; (E.L.-V.); (A.A.); (D.F.)
- Medina Foundation, Technology Park of Health Sciences, Av. del Conocimiento, 34, 18016 Granada, Spain
| | - Diego Franco
- Department of Experimental Biology, University of Jaen, 23071 Jaen, Spain; (E.L.-V.); (A.A.); (D.F.)
- Medina Foundation, Technology Park of Health Sciences, Av. del Conocimiento, 34, 18016 Granada, Spain
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13
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14
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Liu C, Ma N, Guo Z, Zhang Y, Zhang J, Yang F, Su X, Zhang G, Xiong X, Xing Y. Relevance of mitochondrial oxidative stress to arrhythmias: Innovative concepts to target treatments. Pharmacol Res 2021; 175:106027. [PMID: 34890774 DOI: 10.1016/j.phrs.2021.106027] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 11/26/2021] [Accepted: 12/05/2021] [Indexed: 12/13/2022]
Abstract
Cardiac arrhythmia occurs frequently worldwide, and in severe cases can be fatal. Mitochondria are the power plants of cardiomyocytes. In recent studies, mitochondria under certain stimuli produced excessive reactive oxygen species (ROS), which affect the normal function of cardiomyocytes through ion channels and related proteins. Mitochondrial oxidative stress (MOS) plays a key role in diseases with multifactorial etiopathogenesis, such as arrhythmia; MOS can lead to arrhythmias such as atrial fibrillation and ventricular tachycardia. This review discusses the mechanisms of arrhythmias caused by MOS, particularly of ROS produced by mitochondria. MOS can cause arrhythmias by affecting the activities of Ca2+-related proteins, the mitochondrial permeability transition pore protein, connexin 43, hyperpolarization-activated cyclic nucleotide-gated potassium channel 4, and ion channels. Based on these mechanisms, we discuss possible new treatments for arrhythmia. Targeted treatments focusing on mitochondria may reduce the progression of arrhythmias, as well as the occurrence of severe arrhythmias, and may be effective for personalized disease prevention.
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Affiliation(s)
- Can Liu
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Ning Ma
- Dezhou Second People's Hospital, Dezhou 253000, China
| | - Ziru Guo
- Xingtai People's Hospital, Xingtai 054001, China
| | - Yijun Zhang
- The First Affiliated Hospital, Hebei North University, Zhangjiakou 075000, China
| | - Jianzhen Zhang
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100700, China
| | - Fan Yang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Xin Su
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Guoxia Zhang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Xingjiang Xiong
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
| | - Yanwei Xing
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
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15
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Gruscheski L, Brand T. The Role of POPDC Proteins in Cardiac Pacemaking and Conduction. J Cardiovasc Dev Dis 2021; 8:160. [PMID: 34940515 PMCID: PMC8706714 DOI: 10.3390/jcdd8120160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/17/2021] [Accepted: 11/20/2021] [Indexed: 11/17/2022] Open
Abstract
The Popeye domain-containing (POPDC) gene family, consisting of Popdc1 (also known as Bves), Popdc2, and Popdc3, encodes transmembrane proteins abundantly expressed in striated muscle. POPDC proteins have recently been identified as cAMP effector proteins and have been proposed to be part of the protein network involved in cAMP signaling. However, their exact biochemical activity is presently poorly understood. Loss-of-function mutations in animal models causes abnormalities in skeletal muscle regeneration, conduction, and heart rate adaptation after stress. Likewise, patients carrying missense or nonsense mutations in POPDC genes have been associated with cardiac arrhythmias and limb-girdle muscular dystrophy. In this review, we introduce the POPDC protein family, and describe their structure function, and role in cAMP signaling. Furthermore, the pathological phenotypes observed in zebrafish and mouse models and the clinical and molecular pathologies in patients carrying POPDC mutations are described.
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Affiliation(s)
| | - Thomas Brand
- National Heart and Lung Institute, Imperial College London, London W12 0NN, UK;
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16
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Detrimental proarrhythmogenic interaction of Ca 2+/calmodulin-dependent protein kinase II and Na V1.8 in heart failure. Nat Commun 2021; 12:6586. [PMID: 34782600 PMCID: PMC8593192 DOI: 10.1038/s41467-021-26690-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 10/14/2021] [Indexed: 12/19/2022] Open
Abstract
An interplay between Ca2+/calmodulin-dependent protein kinase IIδc (CaMKIIδc) and late Na+ current (INaL) is known to induce arrhythmias in the failing heart. Here, we elucidate the role of the sodium channel isoform NaV1.8 for CaMKIIδc-dependent proarrhythmia. In a CRISPR-Cas9-generated human iPSC-cardiomyocyte homozygous knock-out of NaV1.8, we demonstrate that NaV1.8 contributes to INaL formation. In addition, we reveal a direct interaction between NaV1.8 and CaMKIIδc in cardiomyocytes isolated from patients with heart failure (HF). Using specific blockers of NaV1.8 and CaMKIIδc, we show that NaV1.8-driven INaL is CaMKIIδc-dependent and that NaV1.8-inhibtion reduces diastolic SR-Ca2+ leak in human failing cardiomyocytes. Moreover, increased mortality of CaMKIIδc-overexpressing HF mice is reduced when a NaV1.8 knock-out is introduced. Cellular and in vivo experiments reveal reduced ventricular arrhythmias without changes in HF progression. Our work therefore identifies a proarrhythmic CaMKIIδc downstream target which may constitute a prognostic and antiarrhythmic strategy.
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17
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Ca2+-dependent modulation of voltage-gated myocyte sodium channels. Biochem Soc Trans 2021; 49:1941-1961. [PMID: 34643236 PMCID: PMC8589445 DOI: 10.1042/bst20200604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 08/01/2021] [Accepted: 08/31/2021] [Indexed: 12/19/2022]
Abstract
Voltage-dependent Na+ channel activation underlies action potential generation fundamental to cellular excitability. In skeletal and cardiac muscle this triggers contraction via ryanodine-receptor (RyR)-mediated sarcoplasmic reticular (SR) Ca2+ release. We here review potential feedback actions of intracellular [Ca2+] ([Ca2+]i) on Na+ channel activity, surveying their structural, genetic and cellular and functional implications, translating these to their possible clinical importance. In addition to phosphorylation sites, both Nav1.4 and Nav1.5 possess potentially regulatory binding sites for Ca2+ and/or the Ca2+-sensor calmodulin in their inactivating III–IV linker and C-terminal domains (CTD), where mutations are associated with a range of skeletal and cardiac muscle diseases. We summarize in vitro cell-attached patch clamp studies reporting correspondingly diverse, direct and indirect, Ca2+ effects upon maximal Nav1.4 and Nav1.5 currents (Imax) and their half-maximal voltages (V1/2) characterizing channel gating, in cellular expression systems and isolated myocytes. Interventions increasing cytoplasmic [Ca2+]i down-regulated Imax leaving V1/2 constant in native loose patch clamped, wild-type murine skeletal and cardiac myocytes. They correspondingly reduced action potential upstroke rates and conduction velocities, causing pro-arrhythmic effects in intact perfused hearts. Genetically modified murine RyR2-P2328S hearts modelling catecholaminergic polymorphic ventricular tachycardia (CPVT), recapitulated clinical ventricular and atrial pro-arrhythmic phenotypes following catecholaminergic challenge. These accompanied reductions in action potential conduction velocities. The latter were reversed by flecainide at RyR-blocking concentrations specifically in RyR2-P2328S as opposed to wild-type hearts, suggesting a basis for its recent therapeutic application in CPVT. We finally explore the relevance of these mechanisms in further genetic paradigms for commoner metabolic and structural cardiac disease.
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18
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Chen L, He Y, Wang X, Ge J, Li H. Ventricular voltage-gated ion channels: Detection, characteristics, mechanisms, and drug safety evaluation. Clin Transl Med 2021; 11:e530. [PMID: 34709746 PMCID: PMC8516344 DOI: 10.1002/ctm2.530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 02/06/2023] Open
Abstract
Cardiac voltage-gated ion channels (VGICs) play critical roles in mediating cardiac electrophysiological signals, such as action potentials, to maintain normal heart excitability and contraction. Inherited or acquired alterations in the structure, expression, or function of VGICs, as well as VGIC-related side effects of pharmaceutical drug delivery can result in abnormal cellular electrophysiological processes that induce life-threatening cardiac arrhythmias or even sudden cardiac death. Hence, to reduce possible heart-related risks, VGICs must be acknowledged as important targets in drug discovery and safety studies related to cardiac disease. In this review, we first summarize the development and application of electrophysiological techniques that are employed in cardiac VGIC studies alone or in combination with other techniques such as cryoelectron microscopy, optical imaging and optogenetics. Subsequently, we describe the characteristics, structure, mechanisms, and functions of various well-studied VGICs in ventricular myocytes and analyze their roles in and contributions to both physiological cardiac excitability and inherited cardiac diseases. Finally, we address the implications of the structure and function of ventricular VGICs for drug safety evaluation. In summary, multidisciplinary studies on VGICs help researchers discover potential targets of VGICs and novel VGICs in heart, enrich their knowledge of the properties and functions, determine the operation mechanisms of pathological VGICs, and introduce groundbreaking trends in drug therapy strategies, and drug safety evaluation.
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Affiliation(s)
- Lulan Chen
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
| | - Yue He
- Department of CardiologyShanghai Xuhui District Central Hospital & Zhongshan‐xuhui HospitalShanghaiChina
| | - Xiangdong Wang
- Institute of Clinical Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Junbo Ge
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
| | - Hua Li
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
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19
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Rivaud MR, Delmar M, Remme CA. Heritable arrhythmia syndromes associated with abnormal cardiac sodium channel function: ionic and non-ionic mechanisms. Cardiovasc Res 2021; 116:1557-1570. [PMID: 32251506 PMCID: PMC7341171 DOI: 10.1093/cvr/cvaa082] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/01/2020] [Accepted: 04/01/2020] [Indexed: 12/19/2022] Open
Abstract
The cardiac sodium channel NaV1.5, encoded by the SCN5A gene, is responsible for the fast upstroke of the action potential. Mutations in SCN5A may cause sodium channel dysfunction by decreasing peak sodium current, which slows conduction and facilitates reentry-based arrhythmias, and by enhancing late sodium current, which prolongs the action potential and sets the stage for early afterdepolarization and arrhythmias. Yet, some NaV1.5-related disorders, in particular structural abnormalities, cannot be directly or solely explained on the basis of defective NaV1.5 expression or biophysics. An emerging concept that may explain the large disease spectrum associated with SCN5A mutations centres around the multifunctionality of the NaV1.5 complex. In this alternative view, alterations in NaV1.5 affect processes that are independent of its canonical ion-conducting role. We here propose a novel classification of NaV1.5 (dys)function, categorized into (i) direct ionic effects of sodium influx through NaV1.5 on membrane potential and consequent action potential generation, (ii) indirect ionic effects of sodium influx on intracellular homeostasis and signalling, and (iii) non-ionic effects of NaV1.5, independent of sodium influx, through interactions with macromolecular complexes within the different microdomains of the cardiomyocyte. These indirect ionic and non-ionic processes may, acting alone or in concert, contribute significantly to arrhythmogenesis. Hence, further exploration of these multifunctional effects of NaV1.5 is essential for the development of novel preventive and therapeutic strategies.
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Affiliation(s)
- Mathilde R Rivaud
- Department of Clinical and Experimental Cardiology, Heart Center, Amsterdam UMC (location AMC), University of Amsterdam, Amsterdam Cardiovascular Sciences, Meigberdreef 15, 1105AZ Amsterdam, The Netherlands
| | - Mario Delmar
- The Leon H. Charney Division of Cardiology, New York University School of Medicine, 435 E 30th St, NSB 707, New York, NY 10016, USA
| | - Carol Ann Remme
- Department of Clinical and Experimental Cardiology, Heart Center, Amsterdam UMC (location AMC), University of Amsterdam, Amsterdam Cardiovascular Sciences, Meigberdreef 15, 1105AZ Amsterdam, The Netherlands
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20
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Trum M, Riechel J, Wagner S. Cardioprotection by SGLT2 Inhibitors-Does It All Come Down to Na +? Int J Mol Sci 2021; 22:ijms22157976. [PMID: 34360742 PMCID: PMC8347698 DOI: 10.3390/ijms22157976] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 07/22/2021] [Accepted: 07/22/2021] [Indexed: 12/15/2022] Open
Abstract
Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are emerging as a new treatment strategy for heart failure with reduced ejection fraction (HFrEF) and—depending on the wistfully awaited results of two clinical trials (DELIVER and EMPEROR-Preserved)—may be the first drug class to improve cardiovascular outcomes in patients suffering from heart failure with preserved ejection fraction (HFpEF). Proposed mechanisms of action of this class of drugs are diverse and include metabolic and hemodynamic effects as well as effects on inflammation, neurohumoral activation, and intracellular ion homeostasis. In this review we focus on the growing body of evidence for SGLT2i-mediated effects on cardiac intracellular Na+ as an upstream mechanism. Therefore, we will first give a short overview of physiological cardiomyocyte Na+ handling and its deterioration in heart failure. On this basis we discuss the salutary effects of SGLT2i on Na+ homeostasis by influencing NHE1 activity, late INa as well as CaMKII activity. Finally, we highlight the potential relevance of these effects for systolic and diastolic dysfunction as well as arrhythmogenesis.
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21
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Kim KR, Jeong HJ, Kim Y, Lee SY, Kim Y, Kim HJ, Lee SH, Cho H, Kang JS, Ho WK. Calbindin regulates Kv4.1 trafficking and excitability in dentate granule cells via CaMKII-dependent phosphorylation. Exp Mol Med 2021; 53:1134-1147. [PMID: 34234278 PMCID: PMC8333054 DOI: 10.1038/s12276-021-00645-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 04/13/2021] [Accepted: 04/19/2021] [Indexed: 02/06/2023] Open
Abstract
Calbindin, a major Ca2+ buffer in dentate granule cells (GCs), plays a critical role in shaping Ca2+ signals, yet how it regulates neuronal function remains largely unknown. Here, we found that calbindin knockout (CBKO) mice exhibited dentate GC hyperexcitability and impaired pattern separation, which co-occurred with reduced K+ current due to downregulated surface expression of Kv4.1. Relatedly, manipulation of calbindin expression in HT22 cells led to changes in CaMKII activation and the level of surface localization of Kv4.1 through phosphorylation at serine 555, confirming the mechanism underlying neuronal hyperexcitability in CBKO mice. We also discovered that Ca2+ buffering capacity was significantly reduced in the GCs of Tg2576 mice to the level of CBKO GCs, and this reduction was restored to normal levels by antioxidants, suggesting that calbindin is a target of oxidative stress. Our data suggest that the regulation of CaMKII signaling by Ca2+ buffering is crucial for neuronal excitability regulation.
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Affiliation(s)
- Kyung-Ran Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea
- Institute of BioInnovation Research, Kolon Life Science Inc, 110 Magokdong-ro, Gangseo-gu, Seoul, 07793, Korea
| | - Hyeon-Ju Jeong
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Yoonsub Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea
| | - Seung Yeon Lee
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea
| | - Yujin Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea
- Department of Brain and Cognitive Science, Seoul National University College of Natural Science, Seoul, Korea
| | - Hyun-Ji Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Suk-Ho Lee
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea
- Department of Brain and Cognitive Science, Seoul National University College of Natural Science, Seoul, Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Hana Cho
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Jong-Sun Kang
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Korea.
| | - Won-Kyung Ho
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea.
- Department of Brain and Cognitive Science, Seoul National University College of Natural Science, Seoul, Korea.
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Korea.
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22
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Liu J, Liao X, Zhou J, Li B, Xu L, Liu S, Li Y, Yuan D, Hu C, Jiang W, Yan J. A Rare Variant of ANK3 Is Associated With Intracranial Aneurysm. Front Neurol 2021; 12:672570. [PMID: 34248821 PMCID: PMC8267376 DOI: 10.3389/fneur.2021.672570] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/01/2021] [Indexed: 12/04/2022] Open
Abstract
Intracranial aneurysm (IA) is a cerebrovascular disorder in which abnormal dilation of a blood vessel results from weakening of the blood vessel wall. The aneurysm may rupture, leading to subarachnoid hemorrhage with severe outcomes. This study was conducted to identify the genetic factors involved in the etiology of IA. Whole-exome sequencing was performed in three IA-aggregate families to identify candidate variants. Further association studies of candidate variants were performed among sporadic cases and controls. Bioinformatic analysis was used to predict the functions of candidate genes and variants. Twenty variants were identified after whole-exome sequencing, among which eight were selected for replicative association studies. ANK3 c.4403G>A (p.R1468H) was significantly associated with IA (odds ratio 4.77; 95% confidence interval 1.94–11.67; p-value = 0.00019). Amino acid R1468 in ANK3 was predicted to be located in the spectrin-binding domain of ankyrin-G and may regulate the migration of vascular endothelial cells and affect cell–cell junctions. Therefore, the variation p.R1468H may cause weakening of the artery walls, thereby accelerating the formation of IA. Thus, ANK3 is a candidate gene highly related to IA.
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Affiliation(s)
- Junyu Liu
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
| | - Xin Liao
- Department of Epidemiology and Health Statistics, Xiangya School of Public Health, Central South University, Changsha, China.,The People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Jilin Zhou
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
| | - Bingyang Li
- Department of Epidemiology and Health Statistics, Xiangya School of Public Health, Central South University, Changsha, China
| | - Lu Xu
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
| | - Songlin Liu
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
| | - Yifeng Li
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
| | - Dun Yuan
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
| | - Chongyu Hu
- Department of Neurology, Hunan People's Hospital, Changsha, China
| | - Weixi Jiang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
| | - Junxia Yan
- Department of Epidemiology and Health Statistics, Xiangya School of Public Health, Central South University, Changsha, China.,Hunan Provincial Key Laboratory of Clinical Epidemiology, Xiangya School of Public Health, Central South University, Changsha, China
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23
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Ca 2+/calmodulin kinase II-dependent regulation of β IV-spectrin modulates cardiac fibroblast gene expression, proliferation, and contractility. J Biol Chem 2021; 297:100893. [PMID: 34153319 PMCID: PMC8294584 DOI: 10.1016/j.jbc.2021.100893] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 06/10/2021] [Accepted: 06/17/2021] [Indexed: 01/26/2023] Open
Abstract
Fibrosis is a pronounced feature of heart disease and the result of dysregulated activation of resident cardiac fibroblasts (CFs). Recent work identified stress-induced degradation of the cytoskeletal protein βIV-spectrin as an important step in CF activation and cardiac fibrosis. Furthermore, loss of βIV-spectrin was found to depend on Ca2+/calmodulin-dependent kinase II (CaMKII). Therefore, we sought to determine the mechanism for CaMKII-dependent regulation of βIV-spectrin and CF activity. Computational screening and MS revealed a critical serine residue (S2250 in mouse and S2254 in human) in βIV-spectrin phosphorylated by CaMKII. Disruption of βIV-spectrin/CaMKII interaction or alanine substitution of βIV-spectrin Ser2250 (βIV-S2254A) prevented CaMKII-induced degradation, whereas a phosphomimetic construct (βIV-spectrin with glutamic acid substitution at serine 2254 [βIV-S2254E]) showed accelerated degradation in the absence of CaMKII. To assess the physiological significance of this phosphorylation event, we expressed exogenous βIV-S2254A and βIV-S2254E constructs in βIV-spectrin-deficient CFs, which have increased proliferation and fibrotic gene expression compared with WT CFs. βIV-S2254A but not βIV-S2254E normalized CF proliferation, gene expression, and contractility. Pathophysiological targeting of βIV-spectrin phosphorylation and subsequent degradation was identified in CFs activated with the profibrotic ligand angiotensin II, resulting in increased proliferation and signal transducer and activation of transcription 3 nuclear accumulation. While therapeutic delivery of exogenous WT βIV-spectrin partially reversed these trends, βIV-S2254A completely negated increased CF proliferation and signal transducer and activation of transcription 3 translocation. Moreover, we observed βIV-spectrin phosphorylation and associated loss in total protein within human heart tissue following heart failure. Together, these data illustrate a considerable role for the βIV-spectrin/CaMKII interaction in activating profibrotic signaling.
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Yang Y, Jiang K, Liu X, Qin M, Xiang Y. CaMKII in Regulation of Cell Death During Myocardial Reperfusion Injury. Front Mol Biosci 2021; 8:668129. [PMID: 34141722 PMCID: PMC8204011 DOI: 10.3389/fmolb.2021.668129] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 05/10/2021] [Indexed: 12/11/2022] Open
Abstract
Cardiovascular disease is the leading cause of death worldwide. In spite of the mature managements of myocardial infarction (MI), post-MI reperfusion (I/R) injury results in high morbidity and mortality. Cardiomyocyte Ca2+ overload is a major factor of I/R injury, initiating a cascade of events contributing to cardiomyocyte death and myocardial dysfunction. Ca2+/calmodulin-dependent protein kinase II (CaMKII) plays a critical role in cardiomyocyte death response to I/R injury, whose activation is a key feature of myocardial I/R in causing intracellular mitochondrial swelling, endoplasmic reticulum (ER) Ca2+ leakage, abnormal myofilament contraction, and other adverse reactions. CaMKII is a multifunctional serine/threonine protein kinase, and CaMKIIδ, the dominant subtype in heart, has been widely studied in the activation, location, and related pathways of cardiomyocytes death, which has been considered as a potential targets for pharmacological inhibition. In this review, we summarize a brief overview of CaMKII with various posttranslational modifications and its properties in myocardial I/R injury. We focus on the molecular mechanism of CaMKII involved in regulation of cell death induced by myocardial I/R including necroptosis and pyroptosis of cardiomyocyte. Finally, we highlight that targeting CaMKII modifications and cell death involved pathways may provide new insights to understand the conversion of cardiomyocyte fate in the setting of myocardial I/R injury.
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Affiliation(s)
- Yingjie Yang
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Kai Jiang
- Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xu Liu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Mu Qin
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yaozu Xiang
- Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
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25
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Regulation of Cardiac Conduction and Arrhythmias by Ankyrin/Spectrin-Based Macromolecular Complexes. J Cardiovasc Dev Dis 2021; 8:jcdd8050048. [PMID: 33946725 PMCID: PMC8146975 DOI: 10.3390/jcdd8050048] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/15/2021] [Accepted: 04/19/2021] [Indexed: 12/19/2022] Open
Abstract
The cardiac conduction system is an extended network of excitable tissue tasked with generation and propagation of electrical impulses to signal coordinated contraction of the heart. The fidelity of this system depends on the proper spatio-temporal regulation of ion channels in myocytes throughout the conduction system. Importantly, inherited or acquired defects in a wide class of ion channels has been linked to dysfunction at various stages of the conduction system resulting in life-threatening cardiac arrhythmia. There is growing appreciation of the role that adapter and cytoskeletal proteins play in organizing ion channel macromolecular complexes critical for proper function of the cardiac conduction system. In particular, members of the ankyrin and spectrin families have emerged as important nodes for normal expression and regulation of ion channels in myocytes throughout the conduction system. Human variants impacting ankyrin/spectrin function give rise to a broad constellation of cardiac arrhythmias. Furthermore, chronic neurohumoral and biomechanical stress promotes ankyrin/spectrin loss of function that likely contributes to conduction disturbances in the setting of acquired cardiac disease. Collectively, this review seeks to bring attention to the significance of these cytoskeletal players and emphasize the potential therapeutic role they represent in a myriad of cardiac disease states.
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26
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Zheng Y, Wan X, Yang D, Ramirez-Navarro A, Liu H, Fu JD, Deschênes I. A Heart Failure-Associated SCN5A Splice Variant Leads to a Reduction in Sodium Current Through Coupled-Gating With the Wild-Type Channel. Front Physiol 2021; 12:661429. [PMID: 33828490 PMCID: PMC8019726 DOI: 10.3389/fphys.2021.661429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 03/01/2021] [Indexed: 12/14/2022] Open
Abstract
Nav1.5, encoded by the gene SCN5A, is the predominant voltage-gated sodium channel expressed in the heart. It initiates the cardiac action potential and thus is crucial for normal heart rhythm and function. Dysfunctions in Nav1.5 have been involved in multiple congenital or acquired cardiac pathological conditions such as Brugada syndrome (BrS), Long QT Syndrome Type 3, and heart failure (HF), all of which can lead to sudden cardiac death (SCD) - one of the leading causes of death worldwide. Our lab has previously reported that Nav1.5 forms dimer channels with coupled gating. We also found that Nav1.5 BrS mutants can exert a dominant-negative (DN) effect and impair the function of wildtype (WT) channels through coupled-gating with the WT. It was previously reported that reduction in cardiac sodium currents (INa), observed in HF, could be due to the increased expression of an SCN5A splice variant - E28D, which results in a truncated sodium channel (Nav1.5-G1642X). In this study, we hypothesized that this SCN5A splice variant leads to INa reduction in HF through biophysical coupling with the WT. We showed that Nav1.5-G1642X is a non-functional channel but can interact with the WT, resulting in a DN effect on the WT channel. We found that both WT and the truncated channel Nav1.5-G1642X traffic at the cell surface, suggesting biophysical coupling. Indeed, we found that the DN effect can be abolished by difopein, an inhibitor of the biophysical coupling. Interestingly, the sodium channel polymorphism H558R, which has beneficial effect in HF patients, could also block the DN effect. In summary, the HF-associated splice variant Nav1.5-G1642X suppresses sodium currents in heart failure patients through a mechanism involving coupled-gating with the wildtype sodium channel.
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Affiliation(s)
- Yang Zheng
- Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Xiaoping Wan
- Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Dandan Yang
- Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Angelina Ramirez-Navarro
- Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Haiyan Liu
- Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Ji-Dong Fu
- Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Isabelle Deschênes
- Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States
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27
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Cavus O, Williams J, Musa H, El Refaey M, Gratz D, Shaheen R, Schwieterman NA, Koenig S, Antwi-Boasiako S, Young LJ, Xu X, Han M, Wold LE, Hund TJ, Mohler PJ, Bradley EA. Giant ankyrin-G regulates cardiac function. J Biol Chem 2021; 296:100507. [PMID: 33675749 PMCID: PMC8040283 DOI: 10.1016/j.jbc.2021.100507] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 03/01/2021] [Accepted: 03/02/2021] [Indexed: 11/30/2022] Open
Abstract
Cardiovascular disease (CVD) remains the most common cause of adult morbidity and mortality in developed nations. As a result, predisposition for CVD is increasingly important to understand. Ankyrins are intracellular proteins required for the maintenance of membrane domains. Canonical ankyrin-G (AnkG) has been shown to be vital for normal cardiac function, specifically cardiac excitability, via targeting and regulation of the cardiac voltage-gated sodium channel. Noncanonical (giant) AnkG isoforms play a key role in neuronal membrane biogenesis and excitability, with evidence for human neurologic disease when aberrant. However, the role of giant AnkG in cardiovascular tissue has yet to be explored. Here, we identify giant AnkG in the myocardium and identify that it is enriched in 1-week-old mice. Using a new mouse model lacking giant AnkG expression in myocytes, we identify that young mice displayed a dilated cardiomyopathy phenotype with aberrant electrical conduction and enhanced arrhythmogenicity. Structural and electrical dysfunction occurred at 1 week of age, when giant AnkG was highly expressed and did not appreciably change in adulthood until advanced age. At a cellular level, loss of giant AnkG results in delayed and early afterdepolarizations. However, surprisingly, giant AnkG cKO myocytes display normal INa, but abnormal myocyte contractility, suggesting unique roles of the large isoform in the heart. Finally, transcript analysis provided evidence for unique pathways that may contribute to the structural and electrical findings shown in giant AnkG cKO animals. In summary, we identify a critical role for giant AnkG that adds to the diversity of ankyrin function in the heart.
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Affiliation(s)
- Omer Cavus
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Jordan Williams
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Hassan Musa
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Mona El Refaey
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Dan Gratz
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Rebecca Shaheen
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Neill A Schwieterman
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Sara Koenig
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Steve Antwi-Boasiako
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Lindsay J Young
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Xianyao Xu
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Mei Han
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Loren E Wold
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Thomas J Hund
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA; Department of Internal Medicine/Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Peter J Mohler
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio, USA; The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA; Department of Internal Medicine/Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Elisa A Bradley
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA; Department of Internal Medicine/Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio, USA.
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28
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Nieto-Marín P, Tinaquero D, Utrilla RG, Cebrián J, González-Guerra A, Crespo-García T, Cámara-Checa A, Rubio-Alarcón M, Dago M, Alfayate S, Filgueiras D, Peinado R, López-Sendón JL, Jalife J, Tamargo J, Bernal JA, Caballero R, Delpón E. Tbx5 variants disrupt Nav1.5 function differently in patients diagnosed with Brugada or Long QT Syndrome. Cardiovasc Res 2021; 118:1046-1060. [PMID: 33576403 DOI: 10.1093/cvr/cvab045] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 12/22/2020] [Accepted: 02/04/2021] [Indexed: 12/14/2022] Open
Abstract
AIMS The transcription factor Tbx5 controls cardiogenesis and drives Scn5a expression in mice. We have identified two variants in TBX5 encoding p.D111Y and p.F206L Tbx5, respectively, in two unrelated patients with structurally normal hearts diagnosed with Long QT (LQTS) and Brugada (BrS) Syndrome. Here we characterized the consequences of each variant to unravel the underlying disease mechanisms. METHODS AND RESULTS We combined clinical analysis with in vivo and in vitro electrophysiological and molecular techniques in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), HL-1 cells, and cardiomyocytes from mice trans-expressing human wildtype (WT) or mutant proteins. Tbx5 increased transcription of SCN5A encoding cardiac Nav1.5 channels, while repressing CAMK2D and SPTBN4 genes encoding Ca-calmodulin kinase IIδ (CaMKIIδ) and βIV-spectrin, respectively. These effects significantly increased Na current (INa) in hiPSC-CMs and in cardiomyocytes from mice trans-expressing Tbx5. Consequently, action potential (AP) amplitudes increased and QRS interval narrowed in the mouse electrocardiogram. p.F206L Tbx5 bound to the SCN5A promoter failed to transactivate it, thus precluding the pro-transcriptional effect of WT Tbx5. Therefore, p.F206L markedly decreased INa in hiPSC-CM, HL-1 cells, and mouse cardiomyocytes. The INa decrease in p.F206L trans-expressing mice translated into QRS widening and increased flecainide sensitivity. p.D111Y Tbx5 increased SCN5A expression but failed to repress CAMK2D and SPTBN4. The increased CaMKIIδ and βIV-spectrin significantly augmented the late component of INa (INaL) which, in turn, significantly prolonged AP duration in both hiPSC-CMs and mouse cardiomyocytes. Ranolazine, a selective INaL inhibitor, eliminated the QT and QTc intervals prolongation seen in p.D111Y trans-expressing mice. CONCLUSIONS In addition to peak INa, Tbx5 critically regulates INaL and the duration of repolarization in human cardiomyocytes. Our original results suggest that TBX5 variants associate with and modulate the intensity of the electrical phenotype in LQTS and BrS patients.
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Affiliation(s)
- Paloma Nieto-Marín
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - David Tinaquero
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Raquel G Utrilla
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Jorge Cebrián
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | | | - Teresa Crespo-García
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Anabel Cámara-Checa
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Marcos Rubio-Alarcón
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - María Dago
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Silvia Alfayate
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - David Filgueiras
- Fundación Centro Nacional de Investigaciones Cardiovasculares. 28029-Madrid, Spain
| | - Rafael Peinado
- Department of Cardiology. Hospital Universitario La Paz. Instituto de Investigación Sanitaria la Paz. 28046-Madrid Spain
| | - José Luis López-Sendón
- Department of Cardiology. Hospital Universitario La Paz. Instituto de Investigación Sanitaria la Paz. 28046-Madrid Spain
| | - José Jalife
- Fundación Centro Nacional de Investigaciones Cardiovasculares. 28029-Madrid, Spain.,Departments of Internal Medicine and Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Juan Tamargo
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Juan Antonio Bernal
- Fundación Centro Nacional de Investigaciones Cardiovasculares. 28029-Madrid, Spain
| | - Ricardo Caballero
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Eva Delpón
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
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29
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Lorenzini M, Burel S, Lesage A, Wagner E, Charrière C, Chevillard PM, Evrard B, Maloney D, Ruff KM, Pappu RV, Wagner S, Nerbonne JM, Silva JR, Townsend RR, Maier LS, Marionneau C. Proteomic and functional mapping of cardiac NaV1.5 channel phosphorylation sites. J Gen Physiol 2021; 153:211660. [PMID: 33410863 PMCID: PMC7797897 DOI: 10.1085/jgp.202012646] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 10/23/2020] [Accepted: 12/03/2020] [Indexed: 12/16/2022] Open
Abstract
Phosphorylation of the voltage-gated Na+ (NaV) channel NaV1.5 regulates cardiac excitability, yet the phosphorylation sites regulating its function and the underlying mechanisms remain largely unknown. Using a systematic, quantitative phosphoproteomic approach, we analyzed NaV1.5 channel complexes purified from nonfailing and failing mouse left ventricles, and we identified 42 phosphorylation sites on NaV1.5. Most sites are clustered, and three of these clusters are highly phosphorylated. Analyses of phosphosilent and phosphomimetic NaV1.5 mutants revealed the roles of three phosphosites in regulating NaV1.5 channel expression and gating. The phosphorylated serines S664 and S667 regulate the voltage dependence of channel activation in a cumulative manner, whereas the nearby S671, the phosphorylation of which is increased in failing hearts, regulates cell surface NaV1.5 expression and peak Na+ current. No additional roles could be assigned to the other clusters of phosphosites. Taken together, our results demonstrate that ventricular NaV1.5 is highly phosphorylated and that the phosphorylation-dependent regulation of NaV1.5 channels is highly complex, site specific, and dynamic.
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Affiliation(s)
- Maxime Lorenzini
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Sophie Burel
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Adrien Lesage
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Emily Wagner
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO
| | - Camille Charrière
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Pierre-Marie Chevillard
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Bérangère Evrard
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Dan Maloney
- Bioinformatics Solutions Inc., Waterloo, Ontario, Canada
| | - Kiersten M Ruff
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO
| | - Rohit V Pappu
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO
| | - Stefan Wagner
- Department of Internal Medicine II, University Heart Center, University Hospital Regensburg, Regensburg, Germany
| | - Jeanne M Nerbonne
- Department of Developmental Biology, Washington University Medical School, St. Louis, MO.,Department of Medicine, Washington University Medical School, St. Louis, MO
| | - Jonathan R Silva
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO
| | - R Reid Townsend
- Department of Medicine, Washington University Medical School, St. Louis, MO.,Department of Cell Biology and Physiology, Washington University Medical School, St. Louis, MO
| | - Lars S Maier
- Department of Internal Medicine II, University Heart Center, University Hospital Regensburg, Regensburg, Germany
| | - Céline Marionneau
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
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30
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Morrow JS, Stankewich MC. The Spread of Spectrin in Ataxia and Neurodegenerative Disease. JOURNAL OF EXPERIMENTAL NEUROLOGY 2021; 2:131-139. [PMID: 34528024 PMCID: PMC8439443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Experimental and hereditary defects in the ubiquitous scaffolding proteins of the spectrin gene family cause an array of neuropathologies. Most recognized are ataxias caused by missense, deletions, or truncations in the SPTBN2 gene that encodes beta III spectrin. Such mutations disrupt the organization of post-synaptic receptors, their active transport through the secretory pathway, and the organization and dynamics of the actin-based neuronal skeleton. Similar mutations in SPTAN1 that encodes alpha II spectrin cause severe and usually lethal neurodevelopmental defects including one form of early infantile epileptic encephalopathy type 5 (West syndrome). Defects in these and other spectrins are implicated in degenerative and psychiatric conditions. In recent published work, we describe in mice a novel variant of alpha II spectrin that results in a progressive ataxia with widespread neurodegenerative change. The action of this variant is distinct, in that rather than disrupting a constitutive ligand-binding function of spectrin, the mutation alters its response to calcium and calmodulin-regulated signaling pathways including its response to calpain activation. As such, it represents a novel spectrinopathy that targets a key regulatory pathway where calcium and tyrosine kinase signals converge. Here we briefly discuss the various roles of spectrin in neuronal processes and calcium activated regulatory inputs that control its participation in neuronal growth, organization, and remodeling. We hypothesize that damage to the neuronal spectrin scaffold may be a common final pathway in many neurodegenerative disorders. Targeting the pathways that regulate spectrin function may thus offer novel avenues for therapeutic intervention.
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Affiliation(s)
- Jon S. Morrow
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, USA,Molecular & Cellular Developmental Biology, Yale University, New Haven, CT 06520, USA,Correspondence should be addressed to Jon S. Morrow; , Michael Stankewich;
| | - Michael C. Stankewich
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, USA,Correspondence should be addressed to Jon S. Morrow; , Michael Stankewich;
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31
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Dewal RS, Greer-Short A, Lane C, Nirengi S, Manzano PA, Hernández-Saavedra D, Wright KR, Nassal D, Baer LA, Mohler PJ, Hund TJ, Stanford KI. Phospho-ablation of cardiac sodium channel Na v1.5 mitigates susceptibility to atrial fibrillation and improves glucose homeostasis under conditions of diet-induced obesity. Int J Obes (Lond) 2021; 45:795-807. [PMID: 33500550 PMCID: PMC8005377 DOI: 10.1038/s41366-021-00742-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 11/19/2020] [Accepted: 01/04/2021] [Indexed: 01/30/2023]
Abstract
BACKGROUND Atrial fibrillation (AF) is the most common sustained arrhythmia, with growing evidence identifying obesity as an important risk factor for the development of AF. Although defective atrial myocyte excitability due to stress-induced remodeling of ion channels is commonly observed in the setting of AF, little is known about the mechanistic link between obesity and AF. Recent studies have identified increased cardiac late sodium current (INa,L) downstream of calmodulin-dependent kinase II (CaMKII) activation as an important driver of AF susceptibility. METHODS Here, we investigated a possible role for CaMKII-dependent INa,L in obesity-induced AF using wild-type (WT) and whole-body knock-in mice that ablates phosphorylation of the Nav1.5 sodium channel and prevents augmentation of the late sodium current (S571A; SA mice). RESULTS A high-fat diet (HFD) increased susceptibility to arrhythmias in WT mice, while SA mice were protected from this effect. Unexpectedly, SA mice had improved glucose homeostasis and decreased body weight compared to WT mice. However, SA mice also had reduced food consumption compared to WT mice. Controlling for food consumption through pair feeding of WT and SA mice abrogated differences in weight gain and AF inducibility, but not atrial fibrosis, premature atrial contractions or metabolic capacity. CONCLUSIONS These data demonstrate a novel role for CaMKII-dependent regulation of Nav1.5 in mediating susceptibility to arrhythmias and whole-body metabolism under conditions of diet-induced obesity.
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Affiliation(s)
- Revati S. Dewal
- grid.412332.50000 0001 1545 0811Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Center for Diabetes and Metabolism Research Center, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH USA
| | - Amara Greer-Short
- grid.261331.40000 0001 2285 7943Department of Biomedical Engineering, The Ohio State University, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH USA
| | - Cemantha Lane
- grid.261331.40000 0001 2285 7943Department of Biomedical Engineering, The Ohio State University, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH USA
| | - Shinsuke Nirengi
- grid.412332.50000 0001 1545 0811Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Center for Diabetes and Metabolism Research Center, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH USA
| | - Pedro Acosta Manzano
- grid.412332.50000 0001 1545 0811Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Center for Diabetes and Metabolism Research Center, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH USA
| | - Diego Hernández-Saavedra
- grid.412332.50000 0001 1545 0811Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Center for Diabetes and Metabolism Research Center, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH USA
| | - Katherine R. Wright
- grid.412332.50000 0001 1545 0811Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Center for Diabetes and Metabolism Research Center, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH USA
| | - Drew Nassal
- grid.261331.40000 0001 2285 7943Department of Biomedical Engineering, The Ohio State University, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH USA
| | - Lisa A. Baer
- grid.412332.50000 0001 1545 0811Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Center for Diabetes and Metabolism Research Center, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH USA
| | - Peter J. Mohler
- grid.412332.50000 0001 1545 0811Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH USA
| | - Thomas J. Hund
- grid.261331.40000 0001 2285 7943Department of Biomedical Engineering, The Ohio State University, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH USA
| | - Kristin I. Stanford
- grid.412332.50000 0001 1545 0811Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Center for Diabetes and Metabolism Research Center, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH USA ,grid.412332.50000 0001 1545 0811Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH USA
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Patel NJ, Nassal DM, Gratz D, Hund TJ. Emerging therapeutic targets for cardiac arrhythmias: role of STAT3 in regulating cardiac fibroblast function. Expert Opin Ther Targets 2020; 25:63-73. [PMID: 33170045 DOI: 10.1080/14728222.2021.1849145] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Introduction : Cardiac fibrosis contributes to the development of cardiovascular disease (CVD) and arrhythmia. Cardiac fibroblasts (CFs) are collagen-producing cells that regulate extracellular matrix (ECM) homeostasis. A complex signaling network has been defined linking environmental stress to changes in CF function and fibrosis. Signal Transducer and Activator of Transcription 3 (STAT3) has emerged as a critical integrator of pro-fibrotic signals in CFs downstream of several established signaling networks. Areas covered : This article provides an overview of STAT3 function in CFs and its involvement in coordinating a vast web of intracellular pro-fibrotic signaling molecules and transcription factors. We highlight recent work elucidating a critical role for the fibroblast cytoskeleton in maintaining spatial and temporal control of STAT3-related signaling . Finally, we discuss potential opportunities and obstacles for therapeutic targeting of STAT3 to modulate cardiac fibrosis and arrhythmias. Relevant publications on the topic were identified through Pubmed. Expert opinion : Therapeutic targeting of STAT3 for CVD and arrhythmias presents unique challenges and opportunities. Thus, it is critical to consider the multimodal and dynamic nature of STAT3 signaling. Going forward, it will be beneficial to consider ways to maintain balanced STAT3 function, rather than large-scale perturbations in STAT3 function.
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Affiliation(s)
- Nehal J Patel
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center , Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, the Ohio State University , Columbus, OH, USA
| | - Drew M Nassal
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center , Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, the Ohio State University , Columbus, OH, USA
| | - Daniel Gratz
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center , Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, the Ohio State University , Columbus, OH, USA
| | - Thomas J Hund
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center , Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, the Ohio State University , Columbus, OH, USA.,Department of Internal Medicine, The Ohio State University Wexner Medical Center , Columbus, OH, USA
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33
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Alexander RPD, Bowie D. Intrinsic plasticity of cerebellar stellate cells is mediated by NMDA receptor regulation of voltage-gated Na + channels. J Physiol 2020; 599:647-665. [PMID: 33146903 DOI: 10.1113/jp280627] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/28/2020] [Indexed: 12/12/2022] Open
Abstract
KEY POINTS We show that NMDA receptors (NMDARs) elicit a long-term increase in the firing rates of inhibitory stellate cells of the cerebellum NMDARs induce intrinsic plasticity through a Ca2+ - and CaMKII-dependent pathway that drives shifts in the activation and inactivation properties of voltage-gated Na+ (Nav ) channels An identical Ca2+ - and CaMKII-dependent signalling pathway is triggered during whole-cell recording which lowers the action potential threshold by causing a hyperpolarizing shift in the gating properties of Nav channels. Our findings open the more general possibility that NMDAR-mediated intrinsic plasticity found in other cerebellar neurons may involve similar shifts in Nav channel gating. ABSTRACT Memory storage in the mammalian brain is mediated not only by long-lasting changes in the efficacy of neurotransmitter receptors but also by long-term modifications to the activity of voltage-gated ion channels. Activity-dependent plasticity of voltage-gated ion channels, or intrinsic plasticity, is found throughout the brain in virtually all neuronal types, including principal cells and interneurons. Although intrinsic plasticity has been identified in neurons of the cerebellum, it has yet to be studied in inhibitory cerebellar stellate cells of the molecular layer which regulate activity outflow from the cerebellar cortex by feedforward inhibition onto Purkinje cells. The study of intrinsic plasticity in stellate cells has been particularly challenging as membrane patch breakthrough in electrophysiology experiments unintentionally triggers changes in spontaneous firing rates. Using cell-attached patch recordings to avoid disruption, we show that activation of extrasynaptic N-methyl-d-aspartate receptors (NMDARs) elicits a long-term increase in the firing properties of stellate cells by stimulating a rise in cytosolic Ca2+ and activation of Ca²⁺/calmodulin-dependent protein kinase II (CaMKII). An identical signalling pathway is triggered during whole-cell recording which lowers the action potential threshold by causing a hyperpolarizing shift in the gating properties of voltage-gated sodium (Nav ) channels. Together, our findings identify an unappreciated role of Nav channel-dependent intrinsic plasticity in cerebellar stellate cells which, in concert with non-canonical NMDAR signalling, provides the cerebellum with an unconventional mechanism to fine-tune motor behaviour.
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Affiliation(s)
- Ryan P D Alexander
- Integrated Program in Neuroscience, McGill University, Montréal, Québec, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
| | - Derek Bowie
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec, Canada
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Structural and Functional Refinement of the Axon Initial Segment in Avian Cochlear Nucleus during Development. J Neurosci 2020; 40:6709-6721. [PMID: 32719016 DOI: 10.1523/jneurosci.3068-19.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 05/25/2020] [Accepted: 06/26/2020] [Indexed: 12/12/2022] Open
Abstract
The axon initial segment (AIS) is involved in action potential initiation. Structural and biophysical characteristics of the AIS differ among cell types and/or brain regions, but the underlying mechanisms remain elusive. Using immunofluorescence and electrophysiological methods, combined with super-resolution imaging, we show in the developing nucleus magnocellularis of the chicken in both sexes that the AIS is refined in a tonotopic region-dependent manner. This process of AIS refinement differs among cells tuned to different frequencies. At hearing onset, the AIS was ∼50 µm long with few voltage-gated sodium channels regardless of tonotopic region. However, after hatching, the AIS matured and displayed an ∼20-µm-long structure with a significant enrichment of sodium channels responsible for an increase in sodium current and a decrease in spike threshold. Moreover, the shortening was more pronounced, while the accumulation of channels was not, in neurons tuned to higher frequency, creating tonotopic differences in the AIS. We conclude that AIS shortening is mediated by disassembly of the cytoskeleton at the distal end of the AIS, despite intact periodicity of the submembranous cytoskeleton across the AIS. Importantly, deprivation of afferent input diminished the shortening in neurons tuned to a higher frequency to a larger extent in posthatch animals, with little effect on the accumulation of sodium channels. Thus, cytoskeletal reorganization and sodium channel enrichment at the AIS are differentially regulated depending on tonotopic region, but work synergistically to optimize neuronal output in the auditory nucleus.SIGNIFICANCE STATEMENT The axon initial segment (AIS) plays fundamental roles in determining neuronal output. The AIS varies structurally and molecularly across tonotopic regions in avian cochlear nucleus. However, the mechanism underlying these variations remains unclear. The AIS is immature around hearing onset, but becomes shorter and accumulates more sodium channels during maturation, with a pronounced shortening and a moderate channel accumulation at higher tonotopic regions. Afferent input adjusts sodium conductance at the AIS by augmenting AIS shortening (via disassembly of cytoskeletons at its distal end) specifically at higher-frequency regions. However, this had little effect on channel accumulation. Thus, cytoskeletal structure and sodium channel accumulation at the AIS are regulated differentially but work synergistically to optimize the neuronal output.
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35
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Zybura AS, Baucum AJ, Rush AM, Cummins TR, Hudmon A. CaMKII enhances voltage-gated sodium channel Nav1.6 activity and neuronal excitability. J Biol Chem 2020; 295:11845-11865. [PMID: 32611770 DOI: 10.1074/jbc.ra120.014062] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/30/2020] [Indexed: 11/06/2022] Open
Abstract
Nav1.6 is the primary voltage-gated sodium channel isoform expressed in mature axon initial segments and nodes, making it critical for initiation and propagation of neuronal impulses. Thus, Nav1.6 modulation and dysfunction may have profound effects on input-output properties of neurons in normal and pathological conditions. Phosphorylation is a powerful and reversible mechanism regulating ion channel function. Because Nav1.6 and the multifunctional Ca2+/CaM-dependent protein kinase II (CaMKII) are independently linked to excitability disorders, we sought to investigate modulation of Nav1.6 function by CaMKII signaling. We show that inhibition of CaMKII, a Ser/Thr protein kinase associated with excitability, synaptic plasticity, and excitability disorders, with the CaMKII-specific peptide inhibitor CN21 reduces transient and persistent currents in Nav1.6-expressing Purkinje neurons by 87%. Using whole-cell voltage clamp of Nav1.6, we show that CaMKII inhibition in ND7/23 and HEK293 cells significantly reduces transient and persistent currents by 72% and produces a 5.8-mV depolarizing shift in the voltage dependence of activation. Immobilized peptide arrays and nanoflow LC-electrospray ionization/MS of Nav1.6 reveal potential sites of CaMKII phosphorylation, specifically Ser-561 and Ser-641/Thr-642 within the first intracellular loop of the channel. Using site-directed mutagenesis to test multiple potential sites of phosphorylation, we show that Ala substitutions of Ser-561 and Ser-641/Thr-642 recapitulate the depolarizing shift in activation and reduction in current density. Computational simulations to model effects of CaMKII inhibition on Nav1.6 function demonstrate dramatic reductions in spontaneous and evoked action potentials in a Purkinje cell model, suggesting that CaMKII modulation of Nav1.6 may be a powerful mechanism to regulate neuronal excitability.
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Affiliation(s)
- Agnes S Zybura
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Anthony J Baucum
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Biology Department, Indiana University-Purdue University Indianapolis, School of Science, Indianapolis, Indiana, USA
| | | | - Theodore R Cummins
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Biology Department, Indiana University-Purdue University Indianapolis, School of Science, Indianapolis, Indiana, USA
| | - Andy Hudmon
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA .,Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
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36
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Liu CH, Seo R, Ho TSY, Stankewich M, Mohler PJ, Hund TJ, Noebels JL, Rasband MN. β spectrin-dependent and domain specific mechanisms for Na + channel clustering. eLife 2020; 9:e56629. [PMID: 32425157 PMCID: PMC7237202 DOI: 10.7554/elife.56629] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 05/07/2020] [Indexed: 12/23/2022] Open
Abstract
Previously, we showed that a hierarchy of spectrin cytoskeletal proteins maintains nodal Na+ channels (Liu et al., 2020). Here, using mice lacking β1, β4, or β1/β4 spectrins, we show this hierarchy does not function at axon initial segments (AIS). Although β1 spectrin, together with AnkyrinR (AnkR), compensates for loss of nodal β4 spectrin, it cannot compensate at AIS. We show AnkR lacks the domain necessary for AIS localization. Whereas loss of β4 spectrin causes motor impairment and disrupts AIS, loss of β1 spectrin has no discernable effect on central nervous system structure or function. However, mice lacking both neuronal β1 and β4 spectrin show exacerbated nervous system dysfunction compared to mice lacking β1 or β4 spectrin alone, including profound disruption of AIS Na+ channel clustering, progressive loss of nodal Na+ channels, and seizures. These results further define the important role of AIS and nodal spectrins for nervous system function.
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Affiliation(s)
- Cheng-Hsin Liu
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Program in Developmental Biology, Baylor College of MedicineHoustonUnited States
| | - Ryan Seo
- Department of Neurology, Baylor College of MedicineHoustonUnited States
| | - Tammy Szu-Yu Ho
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
| | | | - Peter J Mohler
- Department of Physiology and Cell Biology, The Ohio State UniversityColumbusUnited States
| | - Thomas J Hund
- Department of Biomedical Engineering, The Ohio State UniversityColumbusUnited States
| | - Jeffrey L Noebels
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Department of Neurology, Baylor College of MedicineHoustonUnited States
| | - Matthew N Rasband
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Program in Developmental Biology, Baylor College of MedicineHoustonUnited States
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37
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Zaitsev AV, Warren M. "Heart Oddity": Intrinsically Reduced Excitability in the Right Ventricle Requires Compensation by Regionally Specific Stress Kinase Function. Front Physiol 2020; 11:86. [PMID: 32132931 PMCID: PMC7040197 DOI: 10.3389/fphys.2020.00086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 01/27/2020] [Indexed: 11/13/2022] Open
Abstract
The traditional view of ventricular excitation and conduction is an all-or-nothing response mediated by a regenerative activation of the inward sodium channel, which gives rise to an essentially constant conduction velocity (CV). However, whereas there is no obvious biological need to tune-up ventricular conduction, the principal molecular components determining CV, such as sodium channels, inward-rectifier potassium channels, and gap junctional channels, are known targets of the “stress” protein kinases PKA and calcium/calmodulin dependent protein kinase II (CaMKII), and are thus regulatable by signal pathways converging on these kinases. In this mini-review we will expose deficiencies and controversies in our current understanding of how ventricular conduction is regulated by stress kinases, with a special focus on the chamber-specific dimension in this regulation. In particular, we will highlight an odd property of cardiac physiology: uniform CV in ventricles requires co-existence of mutually opposing gradients in cardiac excitability and stress kinase function. While the biological advantage of this peculiar feature remains obscure, it is important to recognize the clinical implications of this phenomenon pertinent to inherited or acquired conduction diseases and therapeutic interventions modulating activity of PKA or CaMKII.
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Affiliation(s)
- Alexey V Zaitsev
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, United States
| | - Mark Warren
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, United States
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Lebek S, Pichler K, Reuthner K, Trum M, Tafelmeier M, Mustroph J, Camboni D, Rupprecht L, Schmid C, Maier LS, Arzt M, Wagner S. Enhanced CaMKII-Dependent Late I
Na
Induces Atrial Proarrhythmic Activity in Patients With Sleep-Disordered Breathing. Circ Res 2020; 126:603-615. [DOI: 10.1161/circresaha.119.315755] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Rationale:
Sleep-disordered breathing (SDB) is frequently associated with atrial arrhythmias. Increased CaMKII (Ca/calmodulin-dependent protein kinase II) activity has been previously implicated in atrial arrhythmogenesis.
Objective:
We hypothesized that CaMKII-dependent dysregulation of Na current (I
Na
) may contribute to atrial proarrhythmic activity in patients with SDB.
Methods and Results:
We prospectively enrolled 113 patients undergoing elective coronary artery bypass grafting for cross-sectional study and collected right atrial appendage biopsies. The presence of SDB (defined as apnea-hypopnea index ≥15/h) was assessed with a portable SDB monitor the night before surgery. Compared with 56 patients without SDB, patients with SDB (57) showed a significantly increased level of activated CaMKII. Patch clamp was used to measure I
Na
. There was a significantly enhanced late I
Na
, but reduced peak I
Na
due to enhanced steady-state inactivation in atrial myocytes of patients with SDB consistent with significantly increased CaMKII-dependent cardiac Na channel phosphorylation (Na
V
1.5, at serine 571, Western blotting). These gating changes could be fully reversed by acute CaMKII inhibition (AIP [autocamtide-2 related inhibitory peptide]). As a consequence, we observed significantly more cellular afterdepolarizations and more severe premature atrial contractions in atrial trabeculae of patients with SDB, which could be blocked by either AIP or KN93 (N-[2-[[[(E)-3-(4-chlorophenyl)prop-2-enyl]-methylamino]methyl]phenyl]-N-(2-hydroxyethyl)-4-methoxybenzenesulfonamide). In multivariable linear regression models incorporating age, sex, body mass index, existing atrial fibrillation, existing heart failure, diabetes mellitus, and creatinine levels, apnea-hypopnea index was independently associated with increased CaMKII activity, enhanced late I
Na
and correlated with premature atrial contraction severity.
Conclusions:
In atrial myocardium of patients with SDB, increased CaMKII-dependent phosphorylation of Na
V
1.5 results in dysregulation of I
Na
with proarrhythmic activity that was independent from preexisting comorbidities. Inhibition of CaMKII may be useful for prevention or treatment of arrhythmias in SDB.
Clinical Trial Registration:
URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT02877745.
Visual Overview:
An online visual overview is available for this article.
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Affiliation(s)
- Simon Lebek
- From the Department of Internal Medicine II (S.L., K.P., K.R., M. Trum, M. Tafelmeier, J.M., L.S.M., M.A., S.W.), University Hospital Regensburg, Germany
| | - Konstantin Pichler
- From the Department of Internal Medicine II (S.L., K.P., K.R., M. Trum, M. Tafelmeier, J.M., L.S.M., M.A., S.W.), University Hospital Regensburg, Germany
| | - Kathrin Reuthner
- From the Department of Internal Medicine II (S.L., K.P., K.R., M. Trum, M. Tafelmeier, J.M., L.S.M., M.A., S.W.), University Hospital Regensburg, Germany
| | - Maximillian Trum
- From the Department of Internal Medicine II (S.L., K.P., K.R., M. Trum, M. Tafelmeier, J.M., L.S.M., M.A., S.W.), University Hospital Regensburg, Germany
| | - Maria Tafelmeier
- From the Department of Internal Medicine II (S.L., K.P., K.R., M. Trum, M. Tafelmeier, J.M., L.S.M., M.A., S.W.), University Hospital Regensburg, Germany
| | - Julian Mustroph
- From the Department of Internal Medicine II (S.L., K.P., K.R., M. Trum, M. Tafelmeier, J.M., L.S.M., M.A., S.W.), University Hospital Regensburg, Germany
| | - Daniele Camboni
- Department of Cardiothoracic Surgery (D.C., L.R., C.S.), University Hospital Regensburg, Germany
| | - Leopold Rupprecht
- Department of Cardiothoracic Surgery (D.C., L.R., C.S.), University Hospital Regensburg, Germany
| | - Christof Schmid
- Department of Cardiothoracic Surgery (D.C., L.R., C.S.), University Hospital Regensburg, Germany
| | - Lars S. Maier
- From the Department of Internal Medicine II (S.L., K.P., K.R., M. Trum, M. Tafelmeier, J.M., L.S.M., M.A., S.W.), University Hospital Regensburg, Germany
| | - Michael Arzt
- From the Department of Internal Medicine II (S.L., K.P., K.R., M. Trum, M. Tafelmeier, J.M., L.S.M., M.A., S.W.), University Hospital Regensburg, Germany
| | - Stefan Wagner
- From the Department of Internal Medicine II (S.L., K.P., K.R., M. Trum, M. Tafelmeier, J.M., L.S.M., M.A., S.W.), University Hospital Regensburg, Germany
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Nassal D, Gratz D, Hund TJ. Challenges and Opportunities for Therapeutic Targeting of Calmodulin Kinase II in Heart. Front Pharmacol 2020; 11:35. [PMID: 32116711 PMCID: PMC7012788 DOI: 10.3389/fphar.2020.00035] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 01/14/2020] [Indexed: 12/19/2022] Open
Abstract
Heart failure remains a major health burden around the world. Despite great progress in delineation of molecular mechanisms underlying development of disease, standard therapy has not advanced at the same pace. The multifunctional signaling molecule Ca2+/calmodulin-dependent protein kinase II (CaMKII) has received considerable attention over recent years for its central role in maladaptive remodeling and arrhythmias in the setting of chronic disease. However, these basic science discoveries have yet to translate into new therapies for human patients. This review addresses both the promise and barriers to developing translational therapies that target CaMKII signaling to abrogate pathologic remodeling in the setting of chronic disease. Efforts in small molecule design are discussed, as well as alternative targeting approaches that exploit novel avenues for compound delivery and/or genetic approaches to affect cardiac CaMKII signaling. These alternative strategies provide hope for overcoming some of the challenges that have limited the development of new therapies.
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Affiliation(s)
- Drew Nassal
- The Frick Center for Heart Failure and Arrhythmia and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Daniel Gratz
- The Frick Center for Heart Failure and Arrhythmia and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, United States
| | - Thomas J Hund
- The Frick Center for Heart Failure and Arrhythmia and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, United States.,Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, United States
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Takla M, Huang CLH, Jeevaratnam K. The cardiac CaMKII-Na v1.5 relationship: From physiology to pathology. J Mol Cell Cardiol 2020; 139:190-200. [PMID: 31958466 DOI: 10.1016/j.yjmcc.2019.12.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/20/2019] [Accepted: 12/30/2019] [Indexed: 12/19/2022]
Abstract
The SCN5A gene encodes Nav1.5, which, as the cardiac voltage-gated Na+ channel's pore-forming α subunit, is crucial for the initiation and propagation of atrial and ventricular action potentials. The arrhythmogenic propensity of inherited SCN5A mutations implicates the Na+ channel in determining cardiomyocyte excitability under normal conditions. Cytosolic kinases have long been known to alter the kinetic profile of Nav1.5 inactivation via phosphorylation of specific residues. Recent substantiation of both the role of calmodulin-dependent kinase II (CaMKII) in modulating the properties of the Nav1.5 inactivation gate and the significant rise in oxidation-dependent autonomous CaMKII activity in structural heart disease has raised the possibility of a novel pathway for acquired arrhythmias - the CaMKII-Nav1.5 relationship. The aim of this review is to: (1) outline the relationship's translation from physiological adaptation to pathological vicious circle; and (2) discuss the relative merits of each of its components as pharmacological targets.
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Affiliation(s)
- Michael Takla
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL, United Kingdom
| | - Christopher L-H Huang
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL, United Kingdom; Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL, United Kingdom; Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom.
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Yang HQ, Pérez-Hernández M, Sanchez-Alonso J, Shevchuk A, Gorelik J, Rothenberg E, Delmar M, Coetzee WA. Ankyrin-G mediates targeting of both Na + and K ATP channels to the rat cardiac intercalated disc. eLife 2020; 9:52373. [PMID: 31934859 PMCID: PMC7299345 DOI: 10.7554/elife.52373] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 01/11/2020] [Indexed: 12/12/2022] Open
Abstract
We investigated targeting mechanisms of Na+ and KATP channels to the intercalated disk (ICD) of cardiomyocytes. Patch clamp and surface biotinylation data show reciprocal downregulation of each other’s surface density. Mutagenesis of the Kir6.2 ankyrin binding site disrupts this functional coupling. Duplex patch clamping and Angle SICM recordings show that INa and IKATP functionally co-localize at the rat ICD, but not at the lateral membrane. Quantitative STORM imaging show that Na+ and KATP channels are localized close to each other and to AnkG, but not to AnkB, at the ICD. Peptides corresponding to Nav1.5 and Kir6.2 ankyrin binding sites dysregulate targeting of both Na+ and KATP channels to the ICD, but not to lateral membranes. Finally, a clinically relevant gene variant that disrupts KATP channel trafficking also regulates Na+ channel surface expression. The functional coupling between these two channels need to be considered when assessing clinical variants and therapeutics.
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Affiliation(s)
- Hua-Qian Yang
- Pediatrics, NYU School of Medicine, New York, United States
| | | | - Jose Sanchez-Alonso
- National Heart and Lung Institute, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, United Kingdom
| | - Andriy Shevchuk
- Department of Medicine, Imperial College London, London, United Kingdom
| | - Julia Gorelik
- National Heart and Lung Institute, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, United Kingdom
| | - Eli Rothenberg
- Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, United States
| | - Mario Delmar
- Medicine, NYU School of Medicine, New York, United States.,Cell Biology, NYU School of Medicine, New York, United States
| | - William A Coetzee
- Pediatrics, NYU School of Medicine, New York, United States.,Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, United States.,Neuroscience and Physiology, NYU School of Medicine, New York, United States
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El Refaey M, Musa H, Murphy NP, Lubbers ER, Skaf M, Han M, Cavus O, Koenig SN, Wallace MJ, Gratz D, Bradley E, Alsina KM, Wehrens XHT, Hund TJ, Mohler PJ. Protein Phosphatase 2A Regulates Cardiac Na + Channels. Circ Res 2019; 124:737-746. [PMID: 30602331 DOI: 10.1161/circresaha.118.314350] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
RATIONALE Voltage-gated Na+ channel ( INa) function is critical for normal cardiac excitability. However, the Na+ channel late component ( INa,L) is directly associated with potentially fatal forms of congenital and acquired human arrhythmia. CaMKII (Ca2+/calmodulin-dependent kinase II) enhances INa,L in response to increased adrenergic tone. However, the pathways that negatively regulate the CaMKII/Nav1.5 axis are unknown and essential for the design of new therapies to regulate the pathogenic INa,L. OBJECTIVE To define phosphatase pathways that regulate INa,L in vivo. METHODS AND RESULTS A mouse model lacking a key regulatory subunit (B56α) of the PP (protein phosphatase) 2A holoenzyme displayed aberrant action potentials after adrenergic stimulation. Unbiased computational modeling of B56α KO (knockout) mouse myocyte action potentials revealed an unexpected role of PP2A in INa,L regulation that was confirmed by direct INa,L recordings from B56α KO myocytes. Further, B56α KO myocytes display decreased sensitivity to isoproterenol-induced induction of arrhythmogenic INa,L, and reduced CaMKII-dependent phosphorylation of Nav1.5. At the molecular level, PP2A/B56α complex was found to localize and coimmunoprecipitate with the primary cardiac Nav channel, Nav1.5. CONCLUSIONS PP2A regulates Nav1.5 activity in mouse cardiomyocytes. This regulation is critical for pathogenic Nav1.5 late current and requires PP2A-B56α. Our study supports B56α as a novel target for the treatment of arrhythmia.
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Affiliation(s)
- Mona El Refaey
- From the Ohio State University College of Medicine and Wexner Medical Center, The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., D.G., E.B., T.J.H., P.J.M.).,Department of Physiology and Cell Biology, Ohio State University, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., P.J.M.)
| | - Hassan Musa
- From the Ohio State University College of Medicine and Wexner Medical Center, The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., D.G., E.B., T.J.H., P.J.M.).,Department of Physiology and Cell Biology, Ohio State University, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., P.J.M.)
| | - Nathaniel P Murphy
- From the Ohio State University College of Medicine and Wexner Medical Center, The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., D.G., E.B., T.J.H., P.J.M.).,Department of Physiology and Cell Biology, Ohio State University, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., P.J.M.)
| | - Ellen R Lubbers
- From the Ohio State University College of Medicine and Wexner Medical Center, The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., D.G., E.B., T.J.H., P.J.M.).,Department of Physiology and Cell Biology, Ohio State University, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., P.J.M.)
| | - Michel Skaf
- From the Ohio State University College of Medicine and Wexner Medical Center, The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., D.G., E.B., T.J.H., P.J.M.).,Department of Physiology and Cell Biology, Ohio State University, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., P.J.M.)
| | - Mei Han
- From the Ohio State University College of Medicine and Wexner Medical Center, The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., D.G., E.B., T.J.H., P.J.M.).,Department of Physiology and Cell Biology, Ohio State University, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., P.J.M.)
| | - Omer Cavus
- From the Ohio State University College of Medicine and Wexner Medical Center, The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., D.G., E.B., T.J.H., P.J.M.).,Department of Physiology and Cell Biology, Ohio State University, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., P.J.M.)
| | - Sara N Koenig
- From the Ohio State University College of Medicine and Wexner Medical Center, The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., D.G., E.B., T.J.H., P.J.M.).,Department of Physiology and Cell Biology, Ohio State University, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., P.J.M.)
| | - Michael J Wallace
- From the Ohio State University College of Medicine and Wexner Medical Center, The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., D.G., E.B., T.J.H., P.J.M.).,Department of Physiology and Cell Biology, Ohio State University, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., P.J.M.)
| | - Daniel Gratz
- From the Ohio State University College of Medicine and Wexner Medical Center, The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., D.G., E.B., T.J.H., P.J.M.).,Department of Biomedical Engineering, Ohio State University College of Engineering, Columbus (D.G., T.J.H.)
| | - Elisa Bradley
- From the Ohio State University College of Medicine and Wexner Medical Center, The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., D.G., E.B., T.J.H., P.J.M.).,Department of Internal Medicine, Ohio State University College of Medicine, Columbus (E.B., T.J.H., P.J.M.)
| | - Katherina M Alsina
- Department of Molecular Physiology and Biophysics (K.M.A.), Baylor College of Medicine, Houston, TX.,Division of Cardiology, Department of Medicine (K.M.A.), Baylor College of Medicine, Houston, TX.,Division of Cardiology, Department of Pediatrics (K.M.A.), Baylor College of Medicine, Houston, TX
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX (X.H.T.W.)
| | - Thomas J Hund
- From the Ohio State University College of Medicine and Wexner Medical Center, The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., D.G., E.B., T.J.H., P.J.M.).,Department of Internal Medicine, Ohio State University College of Medicine, Columbus (E.B., T.J.H., P.J.M.).,Department of Biomedical Engineering, Ohio State University College of Engineering, Columbus (D.G., T.J.H.)
| | - Peter J Mohler
- From the Ohio State University College of Medicine and Wexner Medical Center, The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., D.G., E.B., T.J.H., P.J.M.).,Department of Internal Medicine, Ohio State University College of Medicine, Columbus (E.B., T.J.H., P.J.M.).,Department of Physiology and Cell Biology, Ohio State University, Columbus (M.E.R., H.M., N.P.M., E.R.L., M.S., M.H., O.C., S.N.K., M.J.W., P.J.M.)
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Gratz D, Winkle AJ, Dalic A, Unudurthi SD, Hund TJ. Computational tools for automated histological image analysis and quantification in cardiac tissue. MethodsX 2019; 7:22-34. [PMID: 31890644 PMCID: PMC6931069 DOI: 10.1016/j.mex.2019.11.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 11/30/2019] [Indexed: 12/25/2022] Open
Abstract
Image processing and quantification is a routine and important task across disciplines in biomedical research. Understanding the effects of disease on the tissue and organ level often requires the use of images, however the process of interpreting those images into data which can be tested for significance is often time intensive, tedious and prone to inaccuracy or bias. When working within resource constraints, these different issues often present a trade-off between time invested in analysis and accuracy. To address these issues, we present two novel open source and publically available tools for automated analysis of histological cardiac tissue samples: Automated Fibrosis Analysis Tool (AFAT) for quantifying fibrosis; and Macrophage Analysis Tool (MAT) for quantifying infiltrating macrophages.
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Affiliation(s)
- Daniel Gratz
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, USA
| | - Alexander J Winkle
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, USA
| | - Alyssa Dalic
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, USA
| | - Sathya D Unudurthi
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, USA
| | - Thomas J Hund
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, USA.,Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
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Patel NJ, Nassal DM, Greer-Short AD, Unudurthi SD, Scandling BW, Gratz D, Xu X, Kalyanasundaram A, Fedorov VV, Accornero F, Mohler PJ, Gooch KJ, Hund TJ. βIV-Spectrin/STAT3 complex regulates fibroblast phenotype, fibrosis, and cardiac function. JCI Insight 2019; 4:131046. [PMID: 31550236 DOI: 10.1172/jci.insight.131046] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/18/2019] [Indexed: 01/30/2023] Open
Abstract
Increased fibrosis is a characteristic remodeling response to biomechanical and neurohumoral stress and a determinant of cardiac mechanical and electrical dysfunction in disease. Stress-induced activation of cardiac fibroblasts (CFs) is a critical step in the fibrotic response, although the precise sequence of events underlying activation of these critical cells in vivo remain unclear. Here, we tested the hypothesis that a βIV-spectrin/STAT3 complex is essential for maintenance of a quiescent phenotype (basal nonactivated state) in CFs. We reported increased fibrosis, decreased cardiac function, and electrical impulse conduction defects in genetic and acquired mouse models of βIV-spectrin deficiency. Loss of βIV-spectrin function promoted STAT3 nuclear accumulation and transcriptional activity, and it altered gene expression and CF activation. Furthermore, we demonstrate that a quiescent phenotype may be restored in βIV-spectrin-deficient fibroblasts by expressing a βIV-spectrin fragment including the STAT3-binding domain or through pharmacological STAT3 inhibition. We found that in vivo STAT3 inhibition abrogates fibrosis and cardiac dysfunction in the setting of global βIV-spectrin deficiency. Finally, we demonstrate that fibroblast-specific deletion of βIV-spectrin is sufficient to induce fibrosis and decreased cardiac function. We propose that the βIV-spectrin/STAT3 complex is a determinant of fibroblast phenotype and fibrosis, with implications for remodeling response in cardiovascular disease (CVD).
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Affiliation(s)
- Nehal J Patel
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Drew M Nassal
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Amara D Greer-Short
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Sathya D Unudurthi
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Benjamin W Scandling
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Daniel Gratz
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Xianyao Xu
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Anuradha Kalyanasundaram
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Physiology and Cell Biology, and
| | - Vadim V Fedorov
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Physiology and Cell Biology, and
| | - Federica Accornero
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Physiology and Cell Biology, and
| | - Peter J Mohler
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Physiology and Cell Biology, and.,Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Keith J Gooch
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Thomas J Hund
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA.,Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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Greer-Short A, Musa H, Alsina KM, Ni L, Word TA, Reynolds JO, Gratz D, Lane C, El-Refaey M, Unudurthi S, Skaf M, Li N, Fedorov VV, Wehrens XHT, Mohler PJ, Hund TJ. Calmodulin kinase II regulates atrial myocyte late sodium current, calcium handling, and atrial arrhythmia. Heart Rhythm 2019; 17:503-511. [PMID: 31622781 DOI: 10.1016/j.hrthm.2019.10.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Indexed: 12/19/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) is the most common type of arrhythmia. Abnormal atrial myocyte Ca2+ handling promotes aberrant membrane excitability and remodeling that are important for atrial arrhythmogenesis. The sequence of molecular events leading to loss of normal atrial myocyte Ca2+ homeostasis is not established. Late Na+ current (INa,L) is increased in atrial myocytes from AF patients together with an increase in activity of Ca2+/calmodulin-dependent kinase II (CaMKII). OBJECTIVE The purpose of this study was to determine whether CaMKII-dependent phosphorylation at Ser571 on NaV1.5 increases atrial INa,L, leading to aberrant atrial Ca2+ cycling, altered electrophysiology, and increased AF risk. METHODS Atrial myocyte electrophysiology, Ca2+ handling, and arrhythmia susceptibility were studied in wild-type and Scn5a knock-in mice expressing phosphomimetic (S571E) or phosphoresistant (S571A) NaV1.5 at Ser571. RESULTS Atrial myocytes from S571E but not S571A mice displayed an increase in INa,L and action potential duration, and with adrenergic stress have increased delayed afterdepolarizations. Frequency of Ca2+ sparks and waves was increased in S571E atrial myocytes compared to wild type. S571E mice showed an increase in atrial events induced by adrenergic stress and AF inducibility in vivo. Isolated S571E atria were more susceptible to spontaneous atrial events, which were abrogated by inhibiting sarcoplasmic reticulum Ca2+ release, CaMKII, or the Na+/Ca2+ exchanger. Expression of phospho-NaV1.5 at Ser571 and autophosphorylated CaMKII were increased in atrial samples from human AF patients. CONCLUSION This study identified CaMKII-dependent regulation of NaV1.5 as an important upstream event in Ca2+ handling defects and abnormal impulse generation in the setting of AF.
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Affiliation(s)
- Amara Greer-Short
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio
| | - Hassan Musa
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Katherina M Alsina
- Cardiovascular Research Institute, Departments of Molecular Physiology & Biophysics, Medicine (Cardiology), Pediatrics (Cardiology), and Neuroscience, Center for Space Medicine, Baylor College of Medicine, Houston, Texas
| | - Li Ni
- Cardiovascular Research Institute, Departments of Molecular Physiology & Biophysics, Medicine (Cardiology), Pediatrics (Cardiology), and Neuroscience, Center for Space Medicine, Baylor College of Medicine, Houston, Texas
| | - Tarah A Word
- Cardiovascular Research Institute, Departments of Molecular Physiology & Biophysics, Medicine (Cardiology), Pediatrics (Cardiology), and Neuroscience, Center for Space Medicine, Baylor College of Medicine, Houston, Texas
| | - Julia O Reynolds
- Cardiovascular Research Institute, Departments of Molecular Physiology & Biophysics, Medicine (Cardiology), Pediatrics (Cardiology), and Neuroscience, Center for Space Medicine, Baylor College of Medicine, Houston, Texas
| | - Daniel Gratz
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio
| | - Cemantha Lane
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio
| | - Mona El-Refaey
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Sathya Unudurthi
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio
| | - Michel Skaf
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Ning Li
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio; Department of Physiology & Cell Biology, The Ohio State University College of Medicine, Columbus, Ohio
| | - Vadim V Fedorov
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio; Department of Physiology & Cell Biology, The Ohio State University College of Medicine, Columbus, Ohio
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Departments of Molecular Physiology & Biophysics, Medicine (Cardiology), Pediatrics (Cardiology), and Neuroscience, Center for Space Medicine, Baylor College of Medicine, Houston, Texas
| | - Peter J Mohler
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio; Department of Physiology & Cell Biology, The Ohio State University College of Medicine, Columbus, Ohio; Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio
| | - Thomas J Hund
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio; Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio.
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Neurodevelopmental mutation of giant ankyrin-G disrupts a core mechanism for axon initial segment assembly. Proc Natl Acad Sci U S A 2019; 116:19717-19726. [PMID: 31451636 PMCID: PMC6765234 DOI: 10.1073/pnas.1909989116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Axon initial segments of vertebrate neurons integrate thousands of dendritic inputs and generate a single outgoing action potential. Giant ankyrin-G associates with most of the molecular components of axon initial segments and is required for their assembly. This study identified 3 human mutations of giant ankyrin-G resulting in impaired neurodevelopment in compound heterozygotes. These mutations prevent transition of giant ankyrin-G from a closed to an open conformation, which normally is regulated by phosphorylation of giant ankyrin-G during maturation of axon initial segments. Giant ankyrin-G thus functions in a signaling pathway that may contribute to activity-dependent plasticity of the axon initial segment as well as provide a therapeutic target for treatment of patients bearing giant ankyrin-G mutations. Giant ankyrin-G (gAnkG) coordinates assembly of axon initial segments (AISs), which are sites of action potential generation located in proximal axons of most vertebrate neurons. Here, we identify a mechanism required for normal neural development in humans that ensures ordered recruitment of gAnkG and β4-spectrin to the AIS. We identified 3 human neurodevelopmental missense mutations located in the neurospecific domain of gAnkG that prevent recruitment of β4-spectrin, resulting in a lower density and more elongated pattern for gAnkG and its partners than in the mature AIS. We found that these mutations inhibit transition of gAnkG from a closed configuration with close apposition of N- and C-terminal domains to an extended state that is required for binding and recruitment of β4-spectrin, and normally occurs early in development of the AIS. We further found that the neurospecific domain is highly phosphorylated in mouse brain, and that phosphorylation at 2 sites (S1982 and S2619) is required for the conformational change and for recruitment of β4-spectrin. Together, these findings resolve a discrete intermediate stage in formation of the AIS that is regulated through phosphorylation of the neurospecific domain of gAnkG.
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Lubbers ER, Murphy NP, Musa H, Huang CYM, Gupta R, Price MV, Han M, Daoud G, Gratz D, El Refaey M, Xu X, Hoeflinger NK, Friel EL, Lancione P, Wallace MJ, Cavus O, Simmons SL, Williams JL, Skaf M, Koenig SN, Janssen PML, Rasband MN, Hund TJ, Mohler PJ. Defining new mechanistic roles for αII spectrin in cardiac function. J Biol Chem 2019; 294:9576-9591. [PMID: 31064843 PMCID: PMC6579463 DOI: 10.1074/jbc.ra119.007714] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/22/2019] [Indexed: 01/04/2023] Open
Abstract
Spectrins are cytoskeletal proteins essential for membrane biogenesis and regulation and serve critical roles in protein targeting and cellular signaling. αII spectrin (SPTAN1) is one of two α spectrin genes and αII spectrin dysfunction is linked to alterations in axon initial segment formation, cortical lamination, and neuronal excitability. Furthermore, human αII spectrin loss-of-function variants cause neurological disease. As global αII spectrin knockout mice are embryonic lethal, the in vivo roles of αII spectrin in adult heart are unknown and untested. Here, based on pronounced alterations in αII spectrin regulation in human heart failure we tested the in vivo roles of αII spectrin in the vertebrate heart. We created a mouse model of cardiomyocyte-selective αII spectrin-deficiency (cKO) and used this model to define the roles of αII spectrin in cardiac function. αII spectrin cKO mice displayed significant structural, cellular, and electrical phenotypes that resulted in accelerated structural remodeling, fibrosis, arrhythmia, and mortality in response to stress. At the molecular level, we demonstrate that αII spectrin plays a nodal role for global cardiac spectrin regulation, as αII spectrin cKO hearts exhibited remodeling of αI spectrin and altered β-spectrin expression and localization. At the cellular level, αII spectrin deficiency resulted in altered expression, targeting, and regulation of cardiac ion channels NaV1.5 and KV4.3. In summary, our findings define critical and unexpected roles for the multifunctional αII spectrin protein in the heart. Furthermore, our work provides a new in vivo animal model to study the roles of αII spectrin in the cardiomyocyte.
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Affiliation(s)
- Ellen R Lubbers
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
- Medical Scientist Training Program
- the Departments of Physiology and Cell Biology and
| | - Nathaniel P Murphy
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
- Medical Scientist Training Program
- the Departments of Physiology and Cell Biology and
| | - Hassan Musa
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Claire Yu-Mei Huang
- the Department of Neuroscience and Integrative Molecular and Biomedical Sciences Graduate Program, Baylor College of Medicine, Houston, Texas 77030, and
| | - Rohan Gupta
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Morgan V Price
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Mei Han
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Georges Daoud
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Daniel Gratz
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
- the Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio 432310
| | - Mona El Refaey
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Xianyao Xu
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Nicole K Hoeflinger
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Emma L Friel
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Peter Lancione
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Michael J Wallace
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Omer Cavus
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Samantha L Simmons
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Jordan L Williams
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Michel Skaf
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Sara N Koenig
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
| | - Paul M L Janssen
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
- the Departments of Physiology and Cell Biology and
- Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University College of Medicine and Wexner Medical Center, Columbus, Ohio 432310
| | - Matthew N Rasband
- the Department of Neuroscience and Integrative Molecular and Biomedical Sciences Graduate Program, Baylor College of Medicine, Houston, Texas 77030, and
| | - Thomas J Hund
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia
- the Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio 432310
- Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University College of Medicine and Wexner Medical Center, Columbus, Ohio 432310
| | - Peter J Mohler
- From the Dorothy M. Davis Heart and Lung Research Institute and Frick Center for Heart Failure and Arrhythmia,
- the Departments of Physiology and Cell Biology and
- Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University College of Medicine and Wexner Medical Center, Columbus, Ohio 432310
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49
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Bezzerides VJ, Caballero A, Wang S, Ai Y, Hylind RJ, Lu F, Heims-Waldron DA, Chambers KD, Zhang D, Abrams DJ, Pu WT. Gene Therapy for Catecholaminergic Polymorphic Ventricular Tachycardia by Inhibition of Ca 2+/Calmodulin-Dependent Kinase II. Circulation 2019; 140:405-419. [PMID: 31155924 PMCID: PMC7274838 DOI: 10.1161/circulationaha.118.038514] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Catecholaminergic polymorphic ventricular tachycardia (CPVT), an inherited cardiac arrhythmia characterized by adrenergically triggered arrhythmias, is inadequately treated by current standard of care. Ca2+/calmodulin-dependent protein kinase II (CaMKII), an adrenergically activated kinase that contributes to arrhythmogenesis in heart disease models, is a candidate therapeutic target in CPVT. However, translation of CaMKII inhibition has been limited by the need for selective CaMKII inhibition in cardiomyocytes. Here, we tested the hypothesis that CaMKII inhibition with a cardiomyocyte-targeted gene therapy strategy would suppress arrhythmia in CPVT mouse models. METHODS We developed AAV9-GFP-AIP, an adeno-associated viral vector in which a potent CaMKII inhibitory peptide, autocamtide-2-related inhibitory peptide [AIP], is fused to green fluorescent protein (GFP) and expressed from a cardiomyocyte selective promoter. The vector was delivered systemically. Arrhythmia burden was evaluated with invasive electrophysiology testing in adult mice. AIP was also tested on induced pluripotent stem cells derived from patients with CPVT with different disease-causing mutations to determine the effectiveness of our proposed therapy on human induced pluripotent stem cell-derived cardiomyocytes and different pathogenic genotypes. RESULTS AAV9-GFP-AIP was robustly expressed in the heart without significant expression in extracardiac tissues, including the brain. Administration of AAV9-GFP-AIP to neonatal mice with a known CPVT mutation (RYR2R176Q/+) effectively suppressed ventricular arrhythmias induced by either β-adrenergic stimulation or programmed ventricular pacing, without significant proarrhythmic effect. Intravascular delivery of AAV9-GFP-AIP to adolescent mice transduced ≈50% of cardiomyocytes and was effective in suppressing arrhythmia in CPVT mice. Induced pluripotent stem cell-derived cardiomyocytes derived from 2 different patients with CPVT with different pathogenic mutations demonstrated increased frequency of abnormal calcium release events, which was suppressed by a cell-permeable form of AIP. CONCLUSIONS This proof-of-concept study showed that AAV-mediated delivery of a CaMKII peptide inhibitor to the heart was effective in suppressing arrhythmias in a murine model of CPVT. CaMKII inhibition also reversed the arrhythmia phenotype in human CPVT induced pluripotent stem cell-derived cardiomyocyte models with different pathogenic mutations.
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Affiliation(s)
- Vassilios J Bezzerides
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Ana Caballero
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Suya Wang
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Yulan Ai
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Robyn J Hylind
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Fujian Lu
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Danielle A Heims-Waldron
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Kristina D Chambers
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Donghui Zhang
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - Dominic J Abrams
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.)
| | - William T Pu
- Basic and Translational Cardiovascular Research and Inherited Cardiac Arrhythmias Programs, Department of Cardiology, Boston Children's Hospital, Harvard Medical School, MA (V.J.B., A.C., S.W., Y.A., R.J.H., F.L., D.A.H.-W., K.D.C., D.Z., D.J.A., W.T.P.).,Harvard Stem Cell Institute, Cambridge, MA (W.T.P.)
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50
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Zaitsev AV, Torres NS, Cawley KM, Sabry AD, Warren JS, Warren M. Conduction in the right and left ventricle is differentially regulated by protein kinases and phosphatases: implications for arrhythmogenesis. Am J Physiol Heart Circ Physiol 2019; 316:H1507-H1527. [PMID: 30875259 PMCID: PMC6620685 DOI: 10.1152/ajpheart.00660.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 02/19/2019] [Accepted: 03/07/2019] [Indexed: 12/19/2022]
Abstract
The "stress" kinases cAMP-dependent protein kinase (PKA) and calcium/calmodulin-dependent protein kinase II (CaMKII), phosphorylate the Na+ channel Nav1.5 subunit to regulate its function. However, how the channel regulation translates to ventricular conduction is poorly understood. We hypothesized that the stress kinases positively and differentially regulate conduction in the right (RV) and the left (LV) ventricles. We applied the CaMKII blocker KN93 (2.75 μM), PKA blocker H89 (10 μM), and broad-acting phosphatase blocker calyculin (30 nM) in rabbit hearts paced at a cycle length (CL) of 150-8,000 ms. We used optical mapping to determine the distribution of local conduction delays (inverse of conduction velocity). Control hearts exhibited constant and uniform conduction at all tested CLs. Calyculin (15-min perfusion) accelerated conduction, with greater effect in the RV (by 15.3%) than in the LV (by 4.1%; P < 0.05). In contrast, both KN93 and H89 slowed down conduction in a chamber-, time-, and CL-dependent manner, with the strongest effect in the RV outflow tract (RVOT). Combined KN93 and H89 synergistically promoted conduction slowing in the RV (KN93: 24.7%; H89: 29.9%; and KN93 + H89: 114.2%; P = 0.0016) but not the LV. The progressive depression of RV conduction led to conduction block and reentrant arrhythmias. Protein expression levels of both the CaMKII-δ isoform and the PKA catalytic subunit were higher in the RVOT than in the apical LV (P < 0.05). Thus normal RV conduction requires a proper balance between kinase and phosphatase activity. Dysregulation of this balance due to pharmacological interventions or disease is potentially proarrhythmic. NEW & NOTEWORTHY We show that uniform ventricular conduction requires a precise physiological balance of the activities of calcium/calmodulin-dependent protein kinase II (CaMKII), PKA, and phosphatases, which involves region-specific expression of CaMKII and PKA. Inhibiting CaMKII and/or PKA activity elicits nonuniform conduction depression, with the right ventricle becoming vulnerable to the development of conduction disturbances and ventricular fibrillation/ventricular tachycardia.
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Affiliation(s)
- Alexey V Zaitsev
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah , Salt Lake City, Utah
- Department of Bioengineering, University of Utah , Salt Lake City, Utah
| | - Natalia S Torres
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah , Salt Lake City, Utah
| | - Keiko M Cawley
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah , Salt Lake City, Utah
| | - Amira D Sabry
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah , Salt Lake City, Utah
| | - Junco S Warren
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah , Salt Lake City, Utah
- Department of Internal Medicine, School of Medicine, University of Utah , Salt Lake City, Utah
| | - Mark Warren
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah , Salt Lake City, Utah
- Department of Bioengineering, University of Utah , Salt Lake City, Utah
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