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Brandenburg S, Pawlowitz J, Eikenbusch B, Peper J, Kohl T, Mitronova GY, Sossalla S, Hasenfuss G, Wehrens XH, Kohl P, Rog-Zielinska EA, Lehnart SE. Junctophilin-2 expression rescues atrial dysfunction through polyadic junctional membrane complex biogenesis. JCI Insight 2019; 4:127116. [PMID: 31217359 DOI: 10.1172/jci.insight.127116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 05/16/2019] [Indexed: 12/28/2022] Open
Abstract
Atrial dysfunction is highly prevalent and associated with increased severity of heart failure. While rapid excitation-contraction coupling depends on axial junctions in atrial myocytes, the molecular basis of atrial loss of function remains unclear. We identified approximately 5-fold lower junctophilin-2 levels in atrial compared with ventricular tissue in mouse and human hearts. In atrial myocytes, this resulted in subcellular expression of large junctophilin-2 clusters at axial junctions, together with highly phosphorylated ryanodine receptor (RyR2) channels. To investigate the contribution of junctophilin-2 to atrial pathology in adult hearts, we developed a cardiomyocyte-selective junctophilin-2-knockdown model with 0 mortality. Junctophilin-2 knockdown in mice disrupted atrial RyR2 clustering and contractility without hypertrophy or interstitial fibrosis. In contrast, aortic pressure overload resulted in left atrial hypertrophy with decreased junctophilin-2 and RyR2 expression, disrupted axial junctions, and atrial fibrosis. Whereas pressure overload accrued atrial dysfunction and heart failure with 40% mortality, additional junctophilin-2 knockdown greatly exacerbated atrial dysfunction with 100% mortality. Strikingly, transgenic junctophilin-2 overexpression restored atrial contractility and survival through de novo biogenesis of polyadic junctional membrane complexes maintained after pressure overload. Our data show a central role of junctophilin-2 cluster disruption in atrial hypertrophy and identify transgenic augmentation of junctophilin-2 as a disease-mitigating rationale to improve atrial dysfunction and prevent heart failure deterioration.
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Affiliation(s)
- Sören Brandenburg
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Jan Pawlowitz
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Benjamin Eikenbusch
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Jonas Peper
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Tobias Kohl
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Gyuzel Y Mitronova
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Samuel Sossalla
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany
| | - Gerd Hasenfuss
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Xander Ht Wehrens
- Cardiovascular Research Institute - Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA
| | - Peter Kohl
- University Heart Center, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Eva A Rog-Zielinska
- University Heart Center, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Stephan E Lehnart
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, University Medical Center Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany.,BioMET, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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102
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Zhi Y, Xu C, Sui D, Du J, Xu F, Li Y. Effective Delivery of Hypertrophic miRNA Inhibitor by Cholesterol-Containing Nanocarriers for Preventing Pressure Overload Induced Cardiac Hypertrophy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1900023. [PMID: 31179215 PMCID: PMC6548964 DOI: 10.1002/advs.201900023] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 03/04/2019] [Indexed: 05/15/2023]
Abstract
Persistent cardiac hypertrophy causes heart failure and sudden death. Gene therapy is a promising intervention for this disease, but is limited by the lack of effective delivery systems. Herein, it is reported that CHO-PGEA (cholesterol (CHO)-terminated ethanolamine-aminated poly(glycidyl methacrylate)) can efficiently condense small RNAs into nanosystems for preventing cardiac hypertrophy. CHO-PGEA contains two features: 1) lipophilic cholesterol groups enhance transfection efficiency in cardiomyocytes, 2) abundant hydrophilic hydroxyl groups benefit biocompatibility. miR-182, which is known to downregulate forkhead box O3, is selected as an intervention target and can be blocked by synthetic small RNA inhibitor of miR-182 (miR-182-in). CHO-PGEA can efficiently deliver miR-182-in into hearts. In the mice with aortic coarctation, CHO-PEGA/miR-182-in significantly suppresses cardiac hypertrophy without organ injury. This work demonstrates that CHO-PGEA/miRNA nanosystems are very promising for RNA-based therapeutics to treat heart diseases.
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Affiliation(s)
- Ying Zhi
- Beijing Anzhen HospitalCapital Medical UniversityThe Key Laboratory of Remodeling‐Related Cardiovascular DiseasesMinistry of EducationBeijing Institute of Heart Lung and Blood Vessel DiseasesBeijing100029China
| | - Chen Xu
- Key Lab of Biomedical Materials of Natural Macromolecules (Beijing University of Chemical Technology)Ministry of EducationBeijing Laboratory of Biomedical MaterialsBeijing Advanced Innovation Center for Soft Matter Science and EngineeringBeijing University of Chemical TechnologyBeijing100029China
| | - Dandan Sui
- Key Lab of Biomedical Materials of Natural Macromolecules (Beijing University of Chemical Technology)Ministry of EducationBeijing Laboratory of Biomedical MaterialsBeijing Advanced Innovation Center for Soft Matter Science and EngineeringBeijing University of Chemical TechnologyBeijing100029China
| | - Jie Du
- Beijing Anzhen HospitalCapital Medical UniversityThe Key Laboratory of Remodeling‐Related Cardiovascular DiseasesMinistry of EducationBeijing Institute of Heart Lung and Blood Vessel DiseasesBeijing100029China
| | - Fu‐Jian Xu
- Key Lab of Biomedical Materials of Natural Macromolecules (Beijing University of Chemical Technology)Ministry of EducationBeijing Laboratory of Biomedical MaterialsBeijing Advanced Innovation Center for Soft Matter Science and EngineeringBeijing University of Chemical TechnologyBeijing100029China
| | - Yulin Li
- Beijing Anzhen HospitalCapital Medical UniversityThe Key Laboratory of Remodeling‐Related Cardiovascular DiseasesMinistry of EducationBeijing Institute of Heart Lung and Blood Vessel DiseasesBeijing100029China
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103
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An expanded proteome of cardiac t-tubules. Cardiovasc Pathol 2019; 42:15-20. [PMID: 31202980 DOI: 10.1016/j.carpath.2019.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/29/2019] [Accepted: 05/17/2019] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Transverse tubules (t-tubules) are important structural elements, derived from sarcolemma, found on all striated myocytes. These specialized organelles create a scaffold for many proteins crucial to the effective propagation of signal in cardiac excitation-contraction coupling. The full protein composition of this region is unknown. METHODS We characterized the t-tubule subproteome using 52,033 immunohistochemical images covering 13,203 proteins from the Human Protein Atlas (HPA) cardiac tissue microarrays. We used HPASubC, a suite of Python tools, to rapidly review and classify each image for a specific t-tubule staining pattern. The tools Gene Cards, String 11, and Gene Ontology Consortium as well as literature searches were used to understand pathways and relationships between the proteins. RESULTS There were 96 likely t-tubule proteins identified by HPASubC. Of these, 12 were matrisome proteins and 3 were mitochondrial proteins. A separate literature search identified 50 known t-tubule proteins. A comparison of the 2 lists revealed only 17 proteins in common, including 8 of the matrisome proteins. String11 revealed that 94 of 127 combined t-tubule proteins generated a single interconnected network. CONCLUSION Using HPASubC and the HPA, we identified 78 novel, putative t-tubule proteins and validated 17 within the literature. This expands and improves our knowledge of this important subcellular structure of the cardiac myocyte. This information can be used to identify new structural targets involved in excitation-contraction coupling that may be altered in disease.
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104
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Affiliation(s)
- Ying Fu
- From the Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., R.M.S); and Department of Medicine, University of California Los Angeles (R.M.S.)
| | - Robin M Shaw
- From the Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., R.M.S); and Department of Medicine, University of California Los Angeles (R.M.S.).
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105
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Kong CHT, Bryant SM, Watson JJ, Gadeberg HC, Roth DM, Patel HH, Cannell MB, Orchard CH, James AF. The Effects of Aging on the Regulation of T-Tubular ICa by Caveolin in Mouse Ventricular Myocytes. J Gerontol A Biol Sci Med Sci 2019; 73:711-719. [PMID: 29236992 PMCID: PMC5946816 DOI: 10.1093/gerona/glx242] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 12/07/2017] [Indexed: 11/25/2022] Open
Abstract
Aging is associated with diminished cardiac function in males. Cardiac excitation-contraction coupling in ventricular myocytes involves Ca influx via the Ca current (ICa) and Ca release from the sarcoplasmic reticulum, which occur predominantly at t-tubules. Caveolin-3 regulates t-tubular ICa, partly through protein kinase A (PKA), and both ICa and caveolin-3 decrease with age. We therefore investigated ICa and t-tubule structure and function in cardiomyocytes from male wild-type (WT) and caveolin-3-overexpressing (Cav-3OE) mice at 3 and 24 months of age. In WT cardiomyocytes, t-tubular ICa-density was reduced by ~50% with age while surface ICa density was unchanged. Although regulation by PKA was unaffected by age, inhibition of caveolin-3-binding reduced t-tubular ICa at 3 months, but not at 24 months. While Cav-3OE increased cardiac caveolin-3 protein expression ~2.5-fold at both ages, the age-dependent reduction in caveolin-3 (WT ~35%) was preserved in transgenic mice. Overexpression of caveolin-3 reduced t-tubular ICa density at 3 months but prevented further ICa loss with age. Measurement of Ca release at the t-tubules revealed that the triggering of local Ca release by t-tubular ICa was unaffected by age. In conclusion, the data suggest that the reduction in ICa density with age is associated with the loss of a caveolin-3-dependent mechanism that augments t-tubular ICa density.
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Affiliation(s)
- Cherrie H T Kong
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, UK
| | - Simon M Bryant
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, UK
| | - Judy J Watson
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, UK
| | - Hanne C Gadeberg
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, UK
| | - David M Roth
- VA San Diego Healthcare System and Department of Anesthesiology, University of California, San Diego
| | - Hemal H Patel
- VA San Diego Healthcare System and Department of Anesthesiology, University of California, San Diego
| | - Mark B Cannell
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, UK
| | - Clive H Orchard
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, UK
| | - Andrew F James
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, UK
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106
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Lawless M, Caldwell JL, Radcliffe EJ, Smith CER, Madders GWP, Hutchings DC, Woods LS, Church SJ, Unwin RD, Kirkwood GJ, Becker LK, Pearman CM, Taylor RF, Eisner DA, Dibb KM, Trafford AW. Phosphodiesterase 5 inhibition improves contractile function and restores transverse tubule loss and catecholamine responsiveness in heart failure. Sci Rep 2019; 9:6801. [PMID: 31043634 PMCID: PMC6494852 DOI: 10.1038/s41598-019-42592-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 03/26/2019] [Indexed: 12/13/2022] Open
Abstract
Heart failure (HF) is characterized by poor survival, a loss of catecholamine reserve and cellular structural remodeling in the form of disorganization and loss of the transverse tubule network. Indeed, survival rates for HF are worse than many common cancers and have not improved over time. Tadalafil is a clinically relevant drug that blocks phosphodiesterase 5 with high specificity and is used to treat erectile dysfunction. Using a sheep model of advanced HF, we show that tadalafil treatment improves contractile function, reverses transverse tubule loss, restores calcium transient amplitude and the heart's response to catecholamines. Accompanying these effects, tadalafil treatment normalized BNP mRNA and prevented development of subjective signs of HF. These effects were independent of changes in myocardial cGMP content and were associated with upregulation of both monomeric and dimerized forms of protein kinase G and of the cGMP hydrolyzing phosphodiesterases 2 and 3. We propose that the molecular switch for the loss of transverse tubules in HF and their restoration following tadalafil treatment involves the BAR domain protein Amphiphysin II (BIN1) and the restoration of catecholamine sensitivity is through reductions in G-protein receptor kinase 2, protein phosphatase 1 and protein phosphatase 2 A abundance following phosphodiesterase 5 inhibition.
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Affiliation(s)
- Michael Lawless
- Division of Cardiovascular Sciences, Unit of Cardiac Physiology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - Jessica L Caldwell
- Division of Cardiovascular Sciences, Unit of Cardiac Physiology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - Emma J Radcliffe
- Division of Cardiovascular Sciences, Unit of Cardiac Physiology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - Charlotte E R Smith
- Division of Cardiovascular Sciences, Unit of Cardiac Physiology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - George W P Madders
- Division of Cardiovascular Sciences, Unit of Cardiac Physiology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - David C Hutchings
- Division of Cardiovascular Sciences, Unit of Cardiac Physiology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - Lori S Woods
- Division of Cardiovascular Sciences, Unit of Cardiac Physiology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - Stephanie J Church
- Division of Cardiovascular Sciences, Centre for Advanced Discovery and Experimental Therapeutics, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - Richard D Unwin
- Division of Cardiovascular Sciences, Centre for Advanced Discovery and Experimental Therapeutics, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - Graeme J Kirkwood
- Division of Cardiovascular Sciences, Unit of Cardiac Physiology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - Lorenz K Becker
- Division of Cardiovascular Sciences, Unit of Cardiac Physiology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - Charles M Pearman
- Division of Cardiovascular Sciences, Unit of Cardiac Physiology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - Rebecca F Taylor
- Division of Cardiovascular Sciences, Unit of Cardiac Physiology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - David A Eisner
- Division of Cardiovascular Sciences, Unit of Cardiac Physiology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - Katharine M Dibb
- Division of Cardiovascular Sciences, Unit of Cardiac Physiology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom
| | - Andrew W Trafford
- Division of Cardiovascular Sciences, Unit of Cardiac Physiology, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, 3.24 Core Technology Facility, 46 Grafton Street, Manchester, M13 9NT, United Kingdom.
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107
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Colli DF, Blood SR, Sankarankutty AC, Sachse FB, Frisk M, Louch WE, Kekenes-Huskey PM. A Matched-Filter-Based Algorithm for Subcellular Classification of T-System in Cardiac Tissues. Biophys J 2019; 116:1386-1393. [PMID: 30979553 PMCID: PMC6486484 DOI: 10.1016/j.bpj.2019.03.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 03/04/2019] [Accepted: 03/06/2019] [Indexed: 11/26/2022] Open
Abstract
In mammalian ventricular cardiomyocytes, invaginations of the surface membrane form the transverse tubular system (T-system), which consists of transverse tubules (TTs) that align with sarcomeres and Z-lines as well as longitudinal tubules (LTs) that are present between Z-lines in some species. In many cardiac disease etiologies, the T-system is perturbed, which is believed to promote spatially heterogeneous, dyssynchronous Ca2+ release and inefficient contraction. In general, T-system characterization approaches have been directed primarily at isolated cells and do not detect subcellular T-system heterogeneity. Here, we present MatchedMyo, a matched-filter-based algorithm for subcellular T-system characterization in isolated cardiomyocytes and millimeter-scale myocardial sections. The algorithm utilizes "filters" representative of TTs, LTs, and T-system absence. Application of the algorithm to cardiomyocytes isolated from rat disease models of myocardial infarction (MI), dilated cardiomyopathy induced via aortic banding, and sham surgery confirmed and quantified heterogeneous T-system structure and remodeling. Cardiomyocytes from post-MI hearts exhibited increasing T-system disarray as proximity to the infarct increased. We found significant (p < 0.05, Welch's t-test) increases in LT density within cardiomyocytes proximal to the infarct (12 ± 3%, data reported as mean ± SD, n = 3) versus sham (4 ± 2%, n = 5), but not distal to the infarct (7 ± 1%, n = 3). The algorithm also detected decreases in TTs within 5° of the myocyte minor axis for isolated aortic banding (36 ± 9%, n = 3) and MI cardiomyocytes located intermediate (37 ± 4%, n = 3) and proximal (34 ± 4%, n = 3) to the infarct versus sham (57 ± 12%, n = 5). Application of bootstrapping to rabbit MI tissue revealed distal sections comprised 18.9 ± 1.0% TTs, whereas proximal sections comprised 10.1 ± 0.8% TTs (p < 0.05), a 46.6% decrease. The matched-filter approach therefore provides a robust and scalable technique for T-system characterization from isolated cells through millimeter-scale myocardial sections.
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Affiliation(s)
- Dylan F Colli
- Department of Chemistry, University of Kentucky, Lexington, Kentucky; Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky.
| | - S Ryan Blood
- Department of Chemistry, University of Kentucky, Lexington, Kentucky; Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky
| | - Aparna C Sankarankutty
- Nora Eccles Harrison Cardiovascular Research and Training Institute & Department of Bioengineering, University of Utah, Salt Lake City, Utah
| | - Frank B Sachse
- Nora Eccles Harrison Cardiovascular Research and Training Institute & Department of Bioengineering, University of Utah, Salt Lake City, Utah
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; K.G. Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Peter M Kekenes-Huskey
- Department of Chemistry, University of Kentucky, Lexington, Kentucky; Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky
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108
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Hamilton S, Polina I, Terentyeva R, Bronk P, Kim TY, Roder K, Clements RT, Koren G, Choi BR, Terentyev D. PKA phosphorylation underlies functional recruitment of sarcolemmal SK2 channels in ventricular myocytes from hypertrophic hearts. J Physiol 2019; 598:2847-2873. [PMID: 30771223 PMCID: PMC7496687 DOI: 10.1113/jp277618] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 02/08/2019] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Small-conductance Ca2+ -activated K+ (SK) channels expressed in ventricular myocytes are dormant in health, yet become functional in cardiac disease. SK channels are voltage independent and their gating is controlled by intracellular [Ca2+ ] in a biphasic manner. Submicromolar [Ca2+ ] activates the channel via constitutively-bound calmodulin, whereas higher [Ca2+ ] exerts inhibitory effect during depolarization. Using a rat model of cardiac hypertrophy induced by thoracic aortic banding, we found that functional upregulation of SK2 channels in hypertrophic rat ventricular cardiomyocytes is driven by protein kinase A (PKA) phosphorylation. Using site-directed mutagenesis, we identified serine-465 as the site conferring PKA-dependent effects on SK2 channel function. PKA phosphorylation attenuates ISK rectification by reducing the Ca2+ /voltage-dependent inhibition of SK channels without changing their sensitivity to activating submicromolar [Ca2+ ]i . This mechanism underlies the functional recruitment of SK channels not only in cardiac disease, but also in normal physiology, contributing to repolarization under conditions of enhanced adrenergic drive. ABSTRACT Small-conductance Ca2+ -activated K+ (SK) channels expressed in ventricular myocytes (VMs) are dormant in health, yet become functional in cardiac disease. We aimed to test the hypothesis that post-translational modification of SK channels under conditions accompanied by enhanced adrenergic drive plays a central role in disease-related activation of the channels. We investigated this phenomenon using a rat model of hypertrophy induced by thoracic aortic banding (TAB). Western blot analysis using anti-pan-serine/threonine antibodies demonstrated enhanced phosphorylation of immunoprecipitated SK2 channels in VMs from TAB rats vs. Shams, which was reversible by incubation of the VMs with PKA inhibitor H89 (1 μmol L-1 ). Patch clamped VMs under basal conditions from TABs but not Shams exhibited outward current sensitive to the specific SK inhibitor apamin (100 nmol L-1 ), which was eliminated by inhibition of PKA (1 μmol L-1 ). Beta-adrenergic stimulation (isoproterenol, 100 nmol L-1 ) evoked ISK in VMs from Shams, resulting in shortening of action potentials in VMs and ex vivo optically mapped Sham hearts. Using adenoviral gene transfer, wild-type and mutant SK2 channels were overexpressed in adult rat VMs, revealing serine-465 as the site that elicits PKA-dependent phosphorylation effects on SK2 channel function. Concurrent confocal Ca2+ imaging experiments established that PKA phosphorylation lessens rectification of ISK via reduction Ca2+ /voltage-dependent inhibition of the channels at high [Ca2+ ] without affecting their sensitivity to activation by Ca2+ in the submicromolar range. In conclusion, upregulation of SK channels in diseased VMs is mediated by hyperadrenergic drive in cardiac hypertrophy, with functional effects on the channel conferred by PKA-dependent phosphorylation at serine-465.
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Affiliation(s)
- Shanna Hamilton
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, USA.,Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Iuliia Polina
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, USA.,Medical University of South Carolina, Department of Medicine, Division of Nephrology, Charleston, SC, USA
| | - Radmila Terentyeva
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, USA.,Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Peter Bronk
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, USA
| | - Tae Yun Kim
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, USA
| | - Karim Roder
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, USA
| | - Richard T Clements
- Department of Surgery, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, USA.,Vascular Research Laboratory, Providence Veterans Affairs Medical Center, Providence, RI, USA
| | - Gideon Koren
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, USA
| | - Bum-Rak Choi
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, USA
| | - Dmitry Terentyev
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, USA.,Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA
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109
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Jiang J, Tang M, Huang Z, Chen L. Junctophilins emerge as novel therapeutic targets. J Cell Physiol 2019; 234:16933-16943. [DOI: 10.1002/jcp.28405] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/25/2019] [Accepted: 01/30/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Jinyong Jiang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
| | - Mingzhu Tang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
| | - Zhen Huang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
| | - Linxi Chen
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
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110
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Uchida K, Lopatin AN. Diffusional and Electrical Properties of T-Tubules Are Governed by Their Constrictions and Dilations. Biophys J 2019; 114:437-449. [PMID: 29401441 DOI: 10.1016/j.bpj.2017.11.3742] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 10/27/2017] [Accepted: 11/13/2017] [Indexed: 01/07/2023] Open
Abstract
Cardiac t-tubules (TTs) form a network of complex surface membrane invaginations that is essential for proper excitation-contraction coupling. Although electron and optical microscopy studies provided a wealth of important information about the structure of TTs, assessing their functional properties remains a challenge. In this study, we investigated the diffusional accessibility of TTs in intact isolated adult mouse ventricular myocytes using, to our knowledge, a novel fluorescence-based assay. In this approach, a small part of TTs is first locally filled with fluorescent dextran and then its diffusion out of TTs is monitored after rapid removal of extracellular dextran. In normal cells, diffusion of 3 kDa dextran is characterized by an average time constant of 3.9 ± 1.2 s with the data ranging from 1.8 to 10.5 s. The data are consistent with essentially free diffusion of dextran in TTs although measurable contribution of binding is also evident. TT fluorescence is abolished in cells treated with high concentration of formamide or after hyposmotic stress. Importantly, the assay we use allows for quantitative, repetitive measurements of subtle dynamic changes in TT structure of the same cell that are not possible to observe with other approaches. In particular, dextran diffusion rate decreases two-to-threefold during cell swelling, suggesting significant structural remodeling of TTs. Computer modeling shows that diffusional accessibility and electrical properties of TTs are primarily determined by the constrictions and dilations of individual TTs and that, from a functional perspective, TTs cannot be considered as a network of cylinders of the same average diameter. Constriction/dilation model of cardiac TTs is in a quantitative agreement with previous high-resolution microscopy studies of TT structure and alternative measurements of diffusional and electrical time constants of TTs. The data also show that the apparent electrical length constant of cardiac TTs is likely several-fold smaller than that estimated in earlier studies.
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Affiliation(s)
- Keita Uchida
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Anatoli N Lopatin
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan.
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111
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Xie Y, Yang Y, Galice S, Bers DM, Sato D. Size Matters: Ryanodine Receptor Cluster Size Heterogeneity Potentiates Calcium Waves. Biophys J 2019; 116:530-539. [PMID: 30686487 PMCID: PMC6369574 DOI: 10.1016/j.bpj.2018.12.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 11/11/2018] [Accepted: 12/12/2018] [Indexed: 12/21/2022] Open
Abstract
Ryanodine receptors (RyRs) mediate calcium (Ca)-induced Ca release and intracellular Ca homeostasis. In a cardiac myocyte, RyRs group into clusters of variable size from a few to several hundred RyRs, creating a spatially nonuniform intracellular distribution. It is unclear how heterogeneity of RyR cluster size alters spontaneous sarcoplasmic reticulum (SR) Ca releases (Ca sparks) and arrhythmogenic Ca waves. Here, we tested the impact of heterogeneous RyR cluster size on the initiation of Ca waves. Experimentally, we measured RyR cluster sizes at Ca spark sites in rat ventricular myocytes and further tested functional impacts using a physiologically detailed computational model with spatial and stochastic intracellular Ca dynamics. We found that the spark frequency and amplitude increase nonlinearly with the size of RyR clusters. Larger RyR clusters have lower SR Ca release threshold for local Ca spark initiation and exhibit steeper SR Ca release versus SR Ca load relationship. However, larger RyR clusters tend to lower SR Ca load because of the higher Ca leak rate. Conversely, smaller clusters have a higher threshold and a lower leak, which tends to increase SR Ca load. At the myocyte level, homogeneously large or small RyR clusters limit Ca waves (because of low load for large clusters but low excitability for small clusters). Mixtures of large and small RyR clusters potentiates Ca waves because the enhanced SR Ca load driven by smaller clusters enables Ca wave initiation and propagation from larger RyR clusters. Our study suggests that a spatially heterogeneous distribution of RyR cluster size under pathological conditions may potentiate Ca waves and thus afterdepolarizations and triggered arrhythmias.
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Affiliation(s)
- Yuanfang Xie
- Department of Pharmacology, University of California Davis, Davis, California
| | - Yi Yang
- Department of Pharmacology, University of California Davis, Davis, California
| | - Samuel Galice
- Department of Pharmacology, University of California Davis, Davis, California
| | - Donald M Bers
- Department of Pharmacology, University of California Davis, Davis, California
| | - Daisuke Sato
- Department of Pharmacology, University of California Davis, Davis, California.
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112
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Krzesiak A, Cognard C, Sebille S, Carré G, Bosquet L, Delpech N. High-intensity intermittent training is as effective as moderate continuous training, and not deleterious, in cardiomyocyte remodeling of hypertensive rats. J Appl Physiol (1985) 2019; 126:903-915. [PMID: 30702976 DOI: 10.1152/japplphysiol.00131.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Exercise training offers possible nonpharmacological therapy for cardiovascular diseases including hypertension. High-intensity intermittent exercise (HIIE) training has been shown to have as much or even more beneficial cardiovascular effect in patients with cardiovascular diseases than moderate-intensity continuous exercise (CMIE) training. The aim of this study was to investigate the effects of the two types of training on cardiac remodeling of spontaneously hypertensive rats (SHR) induced by hypertension. Eight-week-old male SHR and normotensive Wistar-Kyoto rats (WKY) were divided into four groups: normotensive and hypertensive control (WKY and SHR-C) and hypertensive trained with CMIE (SHR-T CMIE) or HIIE (SHR-T HIIE). After 8 wk of training or inactivity, maximal running speed (MRS), arterial pressure, and heart weight were all assessed. CMIE or HIIE protocols not only increased final MRS and left ventricular weight/body weight ratio but also reduced mean arterial pressure compared with sedentary group. Then, left ventricular tissue was enzymatically dissociated, and isolated cardiomyocytes were used to highlight the changes induced by physical activity at morphological, mechanical, and molecular levels. Both types of training induced restoration of transverse tubule regularity, decrease in spark site density, and reduction in half-relaxation time of calcium transients. HIIE training, in particular, decreased spark amplitude and width, and increased cardiomyocyte contractility and the expression of sarco(endo)plasmic reticulum Ca2+-ATPase and phospholamban phosphorylated on serine 16. NEW & NOTEWORTHY High-intensity intermittent exercise training induces beneficial remodeling of the left ventricular cardiomyocytes of spontaneously hypertensive rats at the morphological, mechanical, and molecular levels. Results also confirm, at the cellular level, that this type of training, as it appears not to be deleterious, could be applied in rehabilitation of hypertensive patients.
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Affiliation(s)
- A Krzesiak
- Equipe Transferts Ioniques et Rythmicité Cellulaire, Laboratory Signalisation et Transports Ioniques Membranaires, Université de Poitiers, EA 7349, Faculté des Sciences Fondamentales et Appliquées , Poitiers , France.,Laboratoire Mobilité, Vieillissement, and Exercice, EA 6314, Université de Poitiers, Faculté des Sciences du Sport , Poitiers , France
| | - C Cognard
- Equipe Transferts Ioniques et Rythmicité Cellulaire, Laboratory Signalisation et Transports Ioniques Membranaires, Université de Poitiers, EA 7349, Faculté des Sciences Fondamentales et Appliquées , Poitiers , France
| | - S Sebille
- Equipe Transferts Ioniques et Rythmicité Cellulaire, Laboratory Signalisation et Transports Ioniques Membranaires, Université de Poitiers, EA 7349, Faculté des Sciences Fondamentales et Appliquées , Poitiers , France
| | - G Carré
- Equipe Transferts Ioniques et Rythmicité Cellulaire, Laboratory Signalisation et Transports Ioniques Membranaires, Université de Poitiers, EA 7349, Faculté des Sciences Fondamentales et Appliquées , Poitiers , France
| | - L Bosquet
- Laboratoire Mobilité, Vieillissement, and Exercice, EA 6314, Université de Poitiers, Faculté des Sciences du Sport , Poitiers , France
| | - N Delpech
- Laboratoire Mobilité, Vieillissement, and Exercice, EA 6314, Université de Poitiers, Faculté des Sciences du Sport , Poitiers , France
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113
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Jones PP, MacQuaide N, Louch WE. Dyadic Plasticity in Cardiomyocytes. Front Physiol 2018; 9:1773. [PMID: 30618792 PMCID: PMC6298195 DOI: 10.3389/fphys.2018.01773] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/23/2018] [Indexed: 11/13/2022] Open
Abstract
Contraction of cardiomyocytes is dependent on sub-cellular structures called dyads, where invaginations of the surface membrane (t-tubules) form functional junctions with the sarcoplasmic reticulum (SR). Within each dyad, Ca2+ entry through t-tubular L-type Ca2+ channels (LTCCs) elicits Ca2+ release from closely apposed Ryanodine Receptors (RyRs) in the SR membrane. The efficiency of this process is dependent on the density and macroscale arrangement of dyads, but also on the nanoscale organization of LTCCs and RyRs within them. We presently review accumulating data demonstrating the remarkable plasticity of these structures. Dyads are known to form gradually during development, with progressive assembly of both t-tubules and junctional SR terminals, and precise trafficking of LTCCs and RyRs. While dyads can exhibit compensatory remodeling when required, dyadic degradation is believed to promote impaired contractility and arrythmogenesis in cardiac disease. Recent data indicate that this plasticity of dyadic structure/function is dependent on the regulatory proteins junctophilin-2, amphiphysin-2 (BIN1), and caveolin-3, which critically arrange dyadic membranes while stabilizing the position and activity of LTCCs and RyRs. Indeed, emerging evidence indicates that clustering of both channels enables "coupled gating", implying that nanoscale localization and function are intimately linked, and may allow fine-tuning of LTCC-RyR crosstalk. We anticipate that improved understanding of dyadic plasticity will provide greater insight into the processes of cardiac compensation and decompensation, and new opportunities to target the basic mechanisms underlying heart disease.
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Affiliation(s)
- Peter P. Jones
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
- HeartOtago, University of Otago, Dunedin, New Zealand
| | - Niall MacQuaide
- Institute of Cardiovascular Sciences, University of Glasgow, Glasgow, United Kingdom
- Clyde Biosciences, Glasgow, United Kingdom
| | - William E. Louch
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, Oslo, Norway
- KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
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114
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Loucks AD, O'Hara T, Trayanova NA. Degradation of T-Tubular Microdomains and Altered cAMP Compartmentation Lead to Emergence of Arrhythmogenic Triggers in Heart Failure Myocytes: An in silico Study. Front Physiol 2018; 9:1737. [PMID: 30564142 PMCID: PMC6288429 DOI: 10.3389/fphys.2018.01737] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 11/16/2018] [Indexed: 11/13/2022] Open
Abstract
Heart failure (HF) is one of the most common causes of morbidity and mortality worldwide. Although many patients suffering from HF die from sudden cardiac death caused by arrhythmias, the mechanism linking HF remodeling to an increased arrhythmogenic propensity remains incomplete. HF is typically characterized by a progressive loss of transverse tubule (T-tubule) domains, which leads to an altered distribution of L-type calcium channels (LTCCs). Microdomain degradation also causes the disruption of the β2 adrenergic receptor (β2AR) and phosphodiesterase (PDE) signaling localization, normally confined to the dyadic space. The goal of this study was to analyze how these subcellular changes affect the function of LTCCs and lead to the emergence of ventricular cell-level triggers of arrhythmias. To accomplish this, we developed a novel computational model of a human ventricular HF myocyte in which LTCCs were divided into six different populations, based on their location and signaling environment they experience. To do so, we included T-tubular microdomain remodeling which led to a subset of LTCCs to be redistributed from the T-tubular to the surface membrane and allowed for different levels of phosphorylation of LTCCs by PKA, based on the presence of β2ARs and PDEs. The model was used to study the behavior of the LTCC current (ICaL) under basal and sympathetic stimulation and its effect on cellular action potential. Our results showed that channels redistributed from the T-tubular membrane to the bulk of the sarcolemma displayed an altered function in their new, non-native signaling domain. Incomplete calcium dependent inactivation, which resulted in a longer-lasting and larger-in-magnitude LTCC current, was observed when we decoupled LTCCs from ryanodine receptors and removed them from the dyadic space. The magnitude of the LTCC current, especially in the surface sarcolemma, was also increased via phosphorylation by the redistributed β2ARs and PDEs. These changes in LTCC current led to the development of early afterdepolarizations. Thus, our study shows that altered LTCC function is a potential cause for the emergence of cell-level triggers of arrhythmia, and that β2ARs and PDEs present useful therapeutic targets for treatment of HF and prevention of sudden cardiac death.
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Affiliation(s)
- Alexandra D Loucks
- Institute for Computational Medicine and Department of Biomedical Engineering at Johns Hopkins University, Baltimore, MD, United States
| | - Thomas O'Hara
- Institute for Computational Medicine and Department of Biomedical Engineering at Johns Hopkins University, Baltimore, MD, United States
| | - Natalia A Trayanova
- Institute for Computational Medicine and Department of Biomedical Engineering at Johns Hopkins University, Baltimore, MD, United States
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115
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Guo A, Wang Y, Chen B, Wang Y, Yuan J, Zhang L, Hall D, Wu J, Shi Y, Zhu Q, Chen C, Thiel WH, Zhan X, Weiss RM, Zhan F, Musselman CA, Pufall M, Zhu W, Au KF, Hong J, Anderson ME, Grueter CE, Song LS. E-C coupling structural protein junctophilin-2 encodes a stress-adaptive transcription regulator. Science 2018; 362:science.aan3303. [PMID: 30409805 DOI: 10.1126/science.aan3303] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 05/10/2018] [Accepted: 10/24/2018] [Indexed: 11/02/2022]
Abstract
Junctophilin-2 (JP2) is a structural protein required for normal excitation-contraction (E-C) coupling. After cardiac stress, JP2 is cleaved by the calcium ion-dependent protease calpain, which disrupts the E-C coupling ultrastructural machinery and drives heart failure progression. We found that stress-induced proteolysis of JP2 liberates an N-terminal fragment (JP2NT) that translocates to the nucleus, binds to genomic DNA, and controls expression of a spectrum of genes in cardiomyocytes. Transgenic overexpression of JP2NT in mice modifies the transcriptional profile, resulting in attenuated pathological remodeling in response to cardiac stress. Conversely, loss of nuclear JP2NT function accelerates stress-induced development of hypertrophy and heart failure in mutant mice. These data reveal a self-protective mechanism in failing cardiomyocytes that transduce mechanical information (E-C uncoupling) into salutary transcriptional reprogramming in the stressed heart.
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Affiliation(s)
- Ang Guo
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Yihui Wang
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.,Department of Emergency Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Biyi Chen
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Yunhao Wang
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Jinxiang Yuan
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Liyang Zhang
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Duane Hall
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Jennifer Wu
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Yun Shi
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Qi Zhu
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.,Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu 226001, China
| | - Cheng Chen
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.,Department of Emergency Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - William H Thiel
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Xin Zhan
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Robert M Weiss
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Fenghuang Zhan
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Catherine A Musselman
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Miles Pufall
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Weizhong Zhu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu 226001, China
| | - Kin Fai Au
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Jiang Hong
- Department of Emergency Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Mark E Anderson
- Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Chad E Grueter
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.,Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Long-Sheng Song
- Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA. .,Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.,Iowa City Veterans Affairs Medical Center, Iowa City, IA 52242, USA
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116
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Bryant SM, Kong CHT, Watson JJ, Gadeberg HC, Roth DM, Patel HH, Cannell MB, James AF, Orchard CH. Caveolin-3 KO disrupts t-tubule structure and decreases t-tubular I Ca density in mouse ventricular myocytes. Am J Physiol Heart Circ Physiol 2018; 315:H1101-H1111. [PMID: 30028203 PMCID: PMC6415741 DOI: 10.1152/ajpheart.00209.2018] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/25/2018] [Accepted: 07/11/2018] [Indexed: 02/06/2023]
Abstract
Caveolin-3 (Cav-3) is a protein that has been implicated in t-tubule formation and function in cardiac ventricular myocytes. In cardiac hypertrophy and failure, Cav-3 expression decreases, t-tubule structure is disrupted, and excitation-contraction coupling is impaired. However, the extent to which the decrease in Cav-3 expression underlies these changes is unclear. We therefore investigated the structure and function of myocytes isolated from the hearts of Cav-3 knockout (KO) mice. These mice showed cardiac dilatation and decreased ejection fraction in vivo compared with wild-type control mice. Isolated KO myocytes showed cellular hypertrophy, altered t-tubule structure, and decreased L-type Ca2+ channel current ( ICa) density. This decrease in density occurred predominantly in the t-tubules, with no change in total ICa, and was therefore a consequence of the increase in membrane area. Cav-3 KO had no effect on L-type Ca2+ channel expression, and C3SD peptide, which mimics the scaffolding domain of Cav-3, had no effect on ICa in KO myocytes. However, inhibition of PKA using H-89 decreased ICa at the surface and t-tubule membranes in both KO and wild-type myocytes. Cav-3 KO had no significant effect on Na+/Ca2+ exchanger current or Ca2+ release. These data suggest that Cav-3 KO causes cellular hypertrophy, thereby decreasing t-tubular ICa density. NEW & NOTEWORTHY Caveolin-3 (Cav-3) is a protein that inhibits hypertrophic pathways, has been implicated in the formation and function of cardiac t-tubules, and shows decreased expression in heart failure. This study demonstrates that Cav-3 knockout mice show cardiac dysfunction in vivo, while isolated ventricular myocytes show cellular hypertrophy, changes in t-tubule structure, and decreased t-tubular L-type Ca2+ current density, suggesting that decreased Cav-3 expression contributes to these changes in cardiac hypertrophy and failure.
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MESH Headings
- Action Potentials
- Animals
- Calcium Channels, L-Type/metabolism
- Calcium Signaling
- Caveolin 3/deficiency
- Caveolin 3/genetics
- Down-Regulation
- Genetic Predisposition to Disease
- Heart Ventricles/metabolism
- Heart Ventricles/pathology
- Hypertrophy, Left Ventricular/genetics
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/pathology
- Hypertrophy, Left Ventricular/physiopathology
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Phenotype
- Ventricular Dysfunction, Left/genetics
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/pathology
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Function, Left
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Affiliation(s)
- Simon M Bryant
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol , Bristol , United Kingdom
| | - Cherrie H T Kong
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol , Bristol , United Kingdom
| | - Judy J Watson
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol , Bristol , United Kingdom
| | - Hanne C Gadeberg
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol , Bristol , United Kingdom
| | - David M Roth
- Veterans Affairs San Diego Healthcare System and Department of Anesthesiology, University of California-San Diego , La Jolla, California
| | - Hemal H Patel
- Veterans Affairs San Diego Healthcare System and Department of Anesthesiology, University of California-San Diego , La Jolla, California
| | - Mark B Cannell
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol , Bristol , United Kingdom
| | - Andrew F James
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol , Bristol , United Kingdom
| | - Clive H Orchard
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol , Bristol , United Kingdom
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117
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Kolstad TR, van den Brink J, MacQuaide N, Lunde PK, Frisk M, Aronsen JM, Norden ES, Cataliotti A, Sjaastad I, Sejersted OM, Edwards AG, Lines GT, Louch WE. Ryanodine receptor dispersion disrupts Ca 2+ release in failing cardiac myocytes. eLife 2018; 7:39427. [PMID: 30375974 PMCID: PMC6245731 DOI: 10.7554/elife.39427] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 10/24/2018] [Indexed: 12/22/2022] Open
Abstract
Reduced cardiac contractility during heart failure (HF) is linked to impaired Ca2+ release from Ryanodine Receptors (RyRs). We investigated whether this deficit can be traced to nanoscale RyR reorganization. Using super-resolution imaging, we observed dispersion of RyR clusters in cardiomyocytes from post-infarction HF rats, resulting in more numerous, smaller clusters. Functional groupings of RyR clusters which produce Ca2+ sparks (Ca2+ release units, CRUs) also became less solid. An increased fraction of small CRUs in HF was linked to augmented ‘silent’ Ca2+ leak, not visible as sparks. Larger multi-cluster CRUs common in HF also exhibited low fidelity spark generation. When successfully triggered, sparks in failing cells displayed slow kinetics as Ca2+ spread across dispersed CRUs. During the action potential, these slow sparks protracted and desynchronized the overall Ca2+ transient. Thus, nanoscale RyR reorganization during HF augments Ca2+ leak and slows Ca2+ release kinetics, leading to weakened contraction in this disease. The muscle cells of the heart coordinate how they contract and relax in order to produce the heartbeat. During heart failure, these cells become less able to contract. As a result the heart becomes inefficient, pumping less blood around the body. For the cardiac muscle cells to contract, the levels of calcium ions in the cells needs to rapidly increase. In failing hearts, these increases in calcium ion levels are smaller, slower and less well coordinated. It was not known what causes these changes, making it difficult to treat heart failure. Calcium ions are released in cardiac muscle cells through protein channels called ryanodine receptors. These receptors form clusters that allow them to synchronize when they open and close. Could the reorganization of ryanodine receptors account for the problems seen in failing hearts? To investigate, Kolstad et al. examined rat hearts using a technique called super-resolution microscopy. This showed that the clusters of ryanodine receptors break apart during heart failure to form smaller clusters. Further experiments showed that calcium ions ‘leak’ from these smaller clusters, reducing the amount of calcium that can be released into cardiac muscle cells during each heartbeat. Released calcium also spreads between the dispersed clusters, resulting in a slower rise of the calcium levels in the cells. Both changes contribute to weakened contractions of cells in failing hearts. Therefore, heart failure can be traced back to very small rearrangements of the ryanodine receptors. This understanding will help researchers as they investigate new ways to treat heart failure.
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Affiliation(s)
- Terje R Kolstad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | | | - Niall MacQuaide
- Institute of Cardiovascular Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Per Kristian Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,Bjørknes College, Oslo, Norway
| | - Einar S Norden
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,Bjørknes College, Oslo, Norway
| | - Alessandro Cataliotti
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Ole M Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | | | | | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
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118
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Hamilton S, Terentyev D. Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity. Front Physiol 2018. [PMID: 30425651 DOI: 10.3389/fphys.2018.01517, 10.3389/fpls.2018.01517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca2+ transport protein complexes including plasmalemmal L-type Ca2+ channels (LTCC), Na+-Ca2+ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca2+-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca2+ release channels. Here we provide an overview of changes in Ca2+ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca2+ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis.
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Affiliation(s)
- Shanna Hamilton
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
| | - Dmitry Terentyev
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
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119
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Hamilton S, Terentyev D. Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity. Front Physiol 2018; 9:1517. [PMID: 30425651 PMCID: PMC6218530 DOI: 10.3389/fphys.2018.01517] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/09/2018] [Indexed: 12/28/2022] Open
Abstract
A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca2+ transport protein complexes including plasmalemmal L-type Ca2+ channels (LTCC), Na+-Ca2+ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca2+-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca2+ release channels. Here we provide an overview of changes in Ca2+ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca2+ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis.
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Affiliation(s)
- Shanna Hamilton
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
| | - Dmitry Terentyev
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
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120
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Hamilton S, Terentyev D. Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity. Front Physiol 2018; 9:1517. [PMID: 30425651 PMCID: PMC6218530 DOI: 10.3389/fphys.2018.01517,+10.3389/fpls.2018.01517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2022] Open
Abstract
A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca2+ transport protein complexes including plasmalemmal L-type Ca2+ channels (LTCC), Na+-Ca2+ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca2+-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca2+ release channels. Here we provide an overview of changes in Ca2+ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca2+ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis.
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Affiliation(s)
- Shanna Hamilton
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
| | - Dmitry Terentyev
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States,*Correspondence: Dmitry Terentyev,
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121
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Scardigli M, Ferrantini C, Crocini C, Pavone FS, Sacconi L. Interplay Between Sub-Cellular Alterations of Calcium Release and T-Tubular Defects in Cardiac Diseases. Front Physiol 2018; 9:1474. [PMID: 30410446 PMCID: PMC6209824 DOI: 10.3389/fphys.2018.01474] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/28/2018] [Indexed: 12/19/2022] Open
Abstract
Asynchronous Ca2+ release promotes non-homogeneous myofilament activation, leading to mechanical dysfunction, as well as initiation of propagated calcium waves and arrhythmias. Recent advances in microscopy techniques have allowed for optical recordings of local Ca2+ fluxes and action potentials from multiple sub-cellular domains within cardiac cells with unprecedented spatial and temporal resolution. Since then, sub-cellular local information of the spatio-temporal relationship between Ca2+ release and action potential propagation have been unlocked, providing novel mechanistic insights in cardiac excitation-contraction coupling (ECC). Here, we review the promising perspectives arouse from repeatedly probing Ca2+ release at the same sub-cellular location while simultaneously probing multiple locations at the same time within a single cardiac cell. We also compare the results obtained in three different rodent models of cardiac diseases, highlighting disease-specific mechanisms. Slower local Ca2+ release has been observed in regions with defective action potential conduction in diseased cardiac cells. Moreover, significant increment of Ca2+ variability (both in time and in space) has been found in diseased cardiac cells but does not directly correlate with local electrical defects nor with the degree of structural aberrations of the cellular membrane system, suggesting a role for other players of the ECC machinery. We finally explore exciting opportunities provided by the technology for studying different cardiomyocyte populations, as well as for dissecting the mechanisms responsible for subcellular spatio-temporal variability of Ca2+ release.
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Affiliation(s)
- Marina Scardigli
- National Institute of Optics, National Research Council, Florence, Italy.,European Laboratory for Non-Linear Spectroscopy, Florence, Italy
| | - Cecilia Ferrantini
- European Laboratory for Non-Linear Spectroscopy, Florence, Italy.,Division of Physiology, Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Claudia Crocini
- Department of Molecular, Cellular, and Developmental Biology & BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, United States
| | - Francesco S Pavone
- National Institute of Optics, National Research Council, Florence, Italy.,European Laboratory for Non-Linear Spectroscopy, Florence, Italy.,Department of Physics and Astronomy, University of Florence, Florence, Italy
| | - Leonardo Sacconi
- National Institute of Optics, National Research Council, Florence, Italy.,European Laboratory for Non-Linear Spectroscopy, Florence, Italy
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122
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Jayasinghe I, Clowsley AH, de Langen O, Sali SS, Crossman DJ, Soeller C. Shining New Light on the Structural Determinants of Cardiac Couplon Function: Insights From Ten Years of Nanoscale Microscopy. Front Physiol 2018; 9:1472. [PMID: 30405432 PMCID: PMC6204384 DOI: 10.3389/fphys.2018.01472] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 09/28/2018] [Indexed: 12/12/2022] Open
Abstract
Remodelling of the membranes and protein clustering patterns during the pathogenesis of cardiomyopathies has renewed the interest in spatial visualisation of these structures in cardiomyocytes. Coincidental emergence of single molecule (super-resolution) imaging and tomographic electron microscopy tools in the last decade have led to a number of new observations on the structural features of the couplons, the primary sites of excitation-contraction coupling in the heart. In particular, super-resolution and tomographic electron micrographs have revised and refined the classical views of the nanoscale geometries of couplons, t-tubules and the organisation of the principal calcium handling proteins in both healthy and failing hearts. These methods have also allowed the visualisation of some features which were too small to be detected with conventional microscopy tools. With new analytical capabilities such as single-protein mapping, in situ protein quantification, correlative and live cell imaging we are now observing an unprecedented interest in adapting these research tools across the cardiac biophysical research discipline. In this article, we review the depth of the new insights that have been enabled by these tools toward understanding the structure and function of the cardiac couplon. We outline the major challenges that remain in these experiments and emerging avenues of research which will be enabled by these technologies.
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Affiliation(s)
- Izzy Jayasinghe
- Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | | | - Oscar de Langen
- Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Sonali S Sali
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - David J Crossman
- Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Christian Soeller
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
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123
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Wang Y, Chen B, Huang CK, Guo A, Wu J, Zhang X, Chen R, Chen C, Kutschke W, Weiss RM, Boudreau RL, Margulies KB, Hong J, Song LS. Targeting Calpain for Heart Failure Therapy: Implications From Multiple Murine Models. JACC Basic Transl Sci 2018; 3:503-517. [PMID: 30175274 PMCID: PMC6115647 DOI: 10.1016/j.jacbts.2018.05.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 04/20/2018] [Accepted: 05/15/2018] [Indexed: 12/11/2022]
Abstract
Calpain is hyperactivated in human failing hearts and rodent heart failure models of different etiologies. Inhibition of calpain activity with MDL-28170 protects against cardiac dysfunction by preserving JP2 expression and T-tubule ultrastructural integrity in murine models of heart failure. Overexpression of JP2 delays the onset of early cardiac sudden death and heart failure, induced by calpain overactivation.
Heart failure remains a major cause of morbidity and mortality in developed countries. There is still a strong need to devise new mechanism-based treatments for heart failure. Numerous studies have suggested the importance of the Ca2+-dependent protease calpain in cardiac physiology and pathology. However, no drugs are currently under development or testing in human patients to target calpain for heart failure treatment. Herein the data demonstrate that inhibition of calpain activity protects against deleterious ultrastructural remodeling and cardiac dysfunction in multiple rodent models of heart failure, providing compelling evidence that calpain inhibition is a promising therapeutic strategy for heart failure treatment.
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Key Words
- CAPN1-OE, calpain-1 overexpressing
- E-C coupling, excitation-contraction coupling
- EF, ejection fraction
- IP, intraperitoneally
- ISO, isoproterenol
- JP2, junctophilin-2
- JP2-OE, junctophilin-2 overexpressing
- LV, left ventricle/ventricular
- MI, myocardial infarction
- RV, right ventricular
- SR, sarcoplasmic reticulum
- T-tubule, transverse tubule
- T-tubules
- TAB, transverse aortic banding
- TTpower, strength of regularity of the T-tubule system
- WT, wild-type
- calcium
- calpain
- excitation-contraction coupling
- heart failure
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Affiliation(s)
- Yihui Wang
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China.,Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Biyi Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa.,Department of Veterans Affairs Medical Center, Iowa City, Iowa
| | - Chun-Kai Huang
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China.,Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Ang Guo
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Jennifer Wu
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Xiaoming Zhang
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Rong Chen
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China.,Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Cheng Chen
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China.,Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - William Kutschke
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Robert M Weiss
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Ryan L Boudreau
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Kenneth B Margulies
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Jiang Hong
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Long-Sheng Song
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa.,Department of Veterans Affairs Medical Center, Iowa City, Iowa
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124
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Affiliation(s)
- Xander H.T. Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas
- Departments of Molecular Physiology & Biophysics, Department of Medicine (Cardiology), and Department of Pediatrics (Cardiology), Baylor College of Medicine, Houston, Texas
- Center for Space Medicine, Baylor College of Medicine, Houston, Texas
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125
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Basheer WA, Shaw RM. Connexin 43 and CaV1.2 Ion Channel Trafficking in Healthy and Diseased Myocardium. Circ Arrhythm Electrophysiol 2018; 9:e001357. [PMID: 27266274 DOI: 10.1161/circep.115.001357] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 04/29/2016] [Indexed: 11/16/2022]
Affiliation(s)
- Wassim A Basheer
- From the Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA (W.A.B., R.M.S.); and Department of Medicine, University of California Los Angeles (R.M.S.)
| | - Robin M Shaw
- From the Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA (W.A.B., R.M.S.); and Department of Medicine, University of California Los Angeles (R.M.S.).
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126
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Crossman DJ, Shen X, Jüllig M, Munro M, Hou Y, Middleditch M, Shrestha D, Li A, Lal S, Dos Remedios CG, Baddeley D, Ruygrok PN, Soeller C. Increased collagen within the transverse tubules in human heart failure. Cardiovasc Res 2018; 113:879-891. [PMID: 28444133 DOI: 10.1093/cvr/cvx055] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 03/20/2017] [Indexed: 12/22/2022] Open
Abstract
Aims In heart failure transverse-tubule (t-tubule) remodelling disrupts calcium release, and contraction. T-tubules in human failing hearts exhibit increased labelling by wheat germ agglutinin (WGA), a lectin that binds to the dystrophin-associated glycoprotein complex. We hypothesized changes in this complex may explain the increased WGA labelling and contribute to t-tubule remodelling in the failing human heart. In this study we sought to identify the molecules responsible for this increased WGA labelling. Methods and results Confocal and super-resolution fluorescence microscopy and proteomic analyses were used to quantify left ventricle samples from healthy donors and patients with idiopathic dilated cardiomyopathy (IDCM). Confocal microscopy demonstrated both WGA and dystrophin were located at t-tubules. Super-resolution microscopy revealed that WGA labelling of t-tubules is largely located within the lumen while dystrophin was restricted to near the sarcolemma. Western blots probed with WGA reveal a 5.7-fold increase in a 140 kDa band in IDCM. Mass spectrometry identified this band as type VI collagen (Col-VI) comprised of α1(VI), α2(VI), and α3(VI) chains. Pertinently, mutations in Col-VI cause muscular dystrophy. Western blotting identified a 2.4-fold increased expression and 3.2-fold increased WGA binding of Col-VI in IDCM. Confocal images showed that Col-VI is located in the t-tubules and that their diameter increased in the IDCM samples. Super-resolution imaging revealed Col-VI was restricted to the t-tubule lumen where increases were associated with displacement in the sarcolemma as identified from dystrophin labelling. Samples were also labelled for type I, III, and IV collagen. Both confocal and super-resolution imaging identified that these collagens were also present within t-tubule lumen. Conclusion Increased expression and labelling of collagen in IDCM samples indicates fibrosis may contribute to t-tubule remodelling in human heart failure.
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Affiliation(s)
- David J Crossman
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland 1023, New Zealand
| | - Xin Shen
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland 1023, New Zealand
| | - Mia Jüllig
- School of Biological Sciences, University of Auckland, 3a Symonds Street, Auckland 1010, New Zealand
| | - Michelle Munro
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland 1023, New Zealand
| | - Yufeng Hou
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland 1023, New Zealand
| | - Martin Middleditch
- School of Biological Sciences, University of Auckland, 3a Symonds Street, Auckland 1010, New Zealand
| | - Darshan Shrestha
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland 1023, New Zealand
| | - Amy Li
- Bosch Institute, University of Sydney, Fisher Road Sydney, NSW 2006, Australia
| | - Sean Lal
- Bosch Institute, University of Sydney, Fisher Road Sydney, NSW 2006, Australia
| | | | - David Baddeley
- Department of Cell Biology, Yale University, West Campus, 300 Heffernan Drive, Haven, CT 06515, USA
| | - Peter N Ruygrok
- Department of Cardiology, Auckland City Hospital, Auckland 1042, New Zealand
| | - Christian Soeller
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland 1023, New Zealand.,Living Systems Institute and Biomedical Physics, University of Exeter, Stocker Road, Exeter EX4QL, UK
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127
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Bhogal NK, Hasan A, Gorelik J. The Development of Compartmentation of cAMP Signaling in Cardiomyocytes: The Role of T-Tubules and Caveolae Microdomains. J Cardiovasc Dev Dis 2018; 5:jcdd5020025. [PMID: 29751502 PMCID: PMC6023514 DOI: 10.3390/jcdd5020025] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/18/2018] [Accepted: 04/28/2018] [Indexed: 12/26/2022] Open
Abstract
3′-5′-cyclic adenosine monophosphate (cAMP) is a signaling messenger produced in response to the stimulation of cellular receptors, and has a myriad of functional applications depending on the cell type. In the heart, cAMP is responsible for regulating the contraction rate and force; however, cAMP is also involved in multiple other functions. Compartmentation of cAMP production may explain the specificity of signaling following a stimulus. In particular, transverse tubules (T-tubules) and caveolae have been found to be critical structural components for the spatial confinement of cAMP in cardiomyocytes, as exemplified by beta-adrenergic receptor (β-ARs) signaling. Pathological alterations in cardiomyocyte microdomain architecture led to a disruption in compartmentation of the cAMP signal. In this review, we discuss the difference between atrial and ventricular cardiomyocytes in respect to microdomain organization, and the pathological changes of atrial and ventricular cAMP signaling in response to myocyte dedifferentiation. In addition, we review the role of localized phosphodiesterase (PDE) activity in constraining the cAMP signal. Finally, we discuss microdomain biogenesis and maturation of cAMP signaling with the help of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Understanding these mechanisms may help to overcome the detrimental effects of pathological structural remodeling.
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Affiliation(s)
- Navneet K Bhogal
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK.
| | - Alveera Hasan
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK.
| | - Julia Gorelik
- Department of Cardiovascular Sciences, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK.
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128
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Rajagopal V, Bass G, Ghosh S, Hunt H, Walker C, Hanssen E, Crampin E, Soeller C. Creating a Structurally Realistic Finite Element Geometric Model of a Cardiomyocyte to Study the Role of Cellular Architecture in Cardiomyocyte Systems Biology. J Vis Exp 2018. [PMID: 29733314 DOI: 10.3791/56817] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
With the advent of three-dimensional (3D) imaging technologies such as electron tomography, serial-block-face scanning electron microscopy and confocal microscopy, the scientific community has unprecedented access to large datasets at sub-micrometer resolution that characterize the architectural remodeling that accompanies changes in cardiomyocyte function in health and disease. However, these datasets have been under-utilized for investigating the role of cellular architecture remodeling in cardiomyocyte function. The purpose of this protocol is to outline how to create an accurate finite element model of a cardiomyocyte using high resolution electron microscopy and confocal microscopy images. A detailed and accurate model of cellular architecture has significant potential to provide new insights into cardiomyocyte biology, more than experiments alone can garner. The power of this method lies in its ability to computationally fuse information from two disparate imaging modalities of cardiomyocyte ultrastructure to develop one unified and detailed model of the cardiomyocyte. This protocol outlines steps to integrate electron tomography and confocal microscopy images of adult male Wistar (name for a specific breed of albino rat) rat cardiomyocytes to develop a half-sarcomere finite element model of the cardiomyocyte. The procedure generates a 3D finite element model that contains an accurate, high-resolution depiction (on the order of ~35 nm) of the distribution of mitochondria, myofibrils and ryanodine receptor clusters that release the necessary calcium for cardiomyocyte contraction from the sarcoplasmic reticular network (SR) into the myofibril and cytosolic compartment. The model generated here as an illustration does not incorporate details of the transverse-tubule architecture or the sarcoplasmic reticular network and is therefore a minimal model of the cardiomyocyte. Nevertheless, the model can already be applied in simulation-based investigations into the role of cell structure in calcium signaling and mitochondrial bioenergetics, which is illustrated and discussed using two case studies that are presented following the detailed protocol.
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Affiliation(s)
- Vijay Rajagopal
- Cell Structure and Mechanobiology Group, University of Melbourne; Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne; Department of Biomedical Engineering, University of Melbourne;
| | - Gregory Bass
- Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne; Department of Biomedical Engineering, University of Melbourne
| | - Shouryadipta Ghosh
- Cell Structure and Mechanobiology Group, University of Melbourne; Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne; Department of Biomedical Engineering, University of Melbourne
| | - Hilary Hunt
- Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne; School of Mathematics and Statistics, Faculty of Science, University of Melbourne
| | - Cameron Walker
- Department of Engineering Science, University of Auckland
| | - Eric Hanssen
- Advanced Microscopy Facility, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne
| | - Edmund Crampin
- Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne; Department of Biomedical Engineering, University of Melbourne; School of Mathematics and Statistics, Faculty of Science, University of Melbourne; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of Melbourne; School of Medicine, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne
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129
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Bryant SM, Kong CHT, Watson JJ, Gadeberg HC, James AF, Cannell MB, Orchard CH. Caveolin 3-dependent loss of t-tubular I Ca during hypertrophy and heart failure in mice. Exp Physiol 2018; 103:652-665. [PMID: 29473235 PMCID: PMC6099270 DOI: 10.1113/ep086731] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 02/15/2018] [Indexed: 12/29/2022]
Abstract
NEW FINDINGS What is the central question of this study? Heart failure is associated with redistribution of L-type Ca2+ current (ICa ) away from the t-tubule membrane to the surface membrane of cardiac ventricular myocytes. However, the underlying mechanism and its dependence on severity of pathology (hypertrophy versus failure) are unclear. What is the main finding and its importance? Increasing severity of response to transverse aortic constriction, from hypertrophy to failure, was accompanied by graded loss of t-tubular ICa and loss of regulation of ICa by caveolin 3. Thus, the pathological loss of t-tubular ICa , which contributes to impaired excitation-contraction coupling and thereby cardiac function in vivo, appears to be attributable to loss of caveolin 3-dependent stimulation of t-tubular ICa . ABSTRACT Previous work has shown redistribution of L-type Ca2+ current (ICa ) from the t-tubules to the surface membrane of rat ventricular myocytes after myocardial infarction. However, whether this occurs in all species and in response to other insults, the relationship of this redistribution to the severity of the pathology, and the underlying mechanism, are unknown. We have therefore investigated the response of mouse hearts and myocytes to pressure overload induced by transverse aortic constriction (TAC). Male C57BL/6 mice underwent TAC or equivalent sham operation 8 weeks before use. ICa and Ca2+ transients were measured in isolated myocytes, and expression of caveolin 3 (Cav3), junctophilin 2 (Jph2) and bridging integrator 1 (Bin1) was determined. C3SD peptide was used to disrupt Cav3 binding to its protein partners. Some animals showed cardiac hypertrophy in response to TAC with little evidence of heart failure, whereas others showed greater hypertrophy and pulmonary congestion. These graded changes were accompanied by graded cellular hypertrophy, t-tubule disruption, decreased expression of Jph2 and Cav3, and decreased t-tubular ICa density, with no change at the cell surface, and graded impairment of Ca2+ release at t-tubules. C3SD decreased ICa density in control but not in TAC myocytes. These data suggest that the graded changes in cardiac function and size that occur in response to TAC are paralleled by graded changes in cell structure and function, which will contribute to the impaired function observed in vivo. They also suggest that loss of t-tubular ICa is attributable to loss of Cav3-dependent stimulation of ICa .
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Affiliation(s)
- Simon M Bryant
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Cherrie H T Kong
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Judy J Watson
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Hanne C Gadeberg
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Andrew F James
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Mark B Cannell
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Clive H Orchard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
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130
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Power AS, Hickey AJ, Crossman DJ, Loiselle DS, Ward ML. Calcium mishandling impairs contraction in right ventricular hypertrophy prior to overt heart failure. Pflugers Arch 2018. [PMID: 29525825 DOI: 10.1007/s00424-018-2125-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Currently, there are no tailored therapies available for the treatment of right ventricular (RV) hypertrophy, and the cellular mechanisms that underlie the disease are poorly understood. We investigated the cellular changes that occur early in the progression of the disease, when RV hypertrophy is evident, but prior to the onset of heart failure. Intracellular Ca2+ ([Ca2+]i) handling was examined in a rat model of monocrotaline (MCT)-induced pulmonary hypertension and subsequent RV hypertrophy. [Ca2+]i and stress production were measured in isolated RV trabeculae under baseline conditions (1-Hz stimulation, 1.5 mM [Ca2+]o, 37 °C), and in response to inotropic interventions (5-Hz stimulation or 1-μM isoproterenol). Under baseline conditions, MCT trabeculae had impaired Ca2+ release in response to stimulation with a 45% delay in the time-to-peak Ca2+, but there was no difference in the amplitude and decay of the Ca2+ transient, or active stress relative to RV trabeculae from normotensive hearts (CON). Increasing stimulation frequency from 1 to 5 Hz increased stress in CON, but not MCT trabeculae. Similarly, β-adrenergic stimulation with isoproterenol increased Ca2+ transient amplitude and active stress in CON, but not in MCT trabeculae, despite accelerating Ca2+ transient decay in trabeculae from both groups. During isoproterenol treatment, MCT trabeculae showed increased diastolic Ca2+ leak, which may explain the blunted inotropic response to β-adrenergic stimulation. Confocal imaging of trabeculae fixed following functional measurements showed that myocytes were on average wider, and transverse-tubule organisation was disrupted in MCT which provides a mechanism to explain the observed slower release of Ca2+.
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Affiliation(s)
- Amelia S Power
- Department of Physiology, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland, 1023, New Zealand
| | - Anthony J Hickey
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, 1023, New Zealand
| | - David J Crossman
- Department of Physiology, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland, 1023, New Zealand
| | - Denis S Loiselle
- Department of Physiology, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland, 1023, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, 1023, New Zealand
| | - Marie-Louise Ward
- Department of Physiology, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland, 1023, New Zealand.
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131
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Schobesberger S, Wright P, Tokar S, Bhargava A, Mansfield C, Glukhov AV, Poulet C, Buzuk A, Monszpart A, Sikkel M, Harding SE, Nikolaev VO, Lyon AR, Gorelik J. T-tubule remodelling disturbs localized β2-adrenergic signalling in rat ventricular myocytes during the progression of heart failure. Cardiovasc Res 2018; 113:770-782. [PMID: 28505272 PMCID: PMC5437368 DOI: 10.1093/cvr/cvx074] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/11/2017] [Indexed: 11/12/2022] Open
Abstract
Aims Cardiomyocyte β2-adrenergic receptor (β2AR) cyclic adenosine monophosphate (cAMP) signalling is regulated by the receptors' subcellular location within transverse tubules (T-tubules), via interaction with structural and regulatory proteins, which form a signalosome. In chronic heart failure (HF), β2ARs redistribute from T-tubules to the cell surface, which disrupts functional signalosomes and leads to diffuse cAMP signalling. However, the functional consequences of structural changes upon β2AR-cAMP signalling during progression from hypertrophy to advanced HF are unknown. Methods and results Rat left ventricular myocytes were isolated at 4-, 8-, and 16-week post-myocardial infarction (MI), β2ARs were stimulated either via whole-cell perfusion or locally through the nanopipette of the scanning ion conductance microscope. cAMP release was measured via a Förster Resonance Energy Transfer-based sensor Epac2-camps. Confocal imaging of di-8-ANNEPS-stained cells and immunoblotting were used to determine structural alterations. At 4-week post-MI, T-tubule regularity, density and junctophilin-2 (JPH2) expression were significantly decreased. The amplitude of local β2AR-mediated cAMP in T-tubules was reduced and cAMP diffused throughout the cytosol instead of being locally confined. This was accompanied by partial caveolin-3 (Cav-3) dissociation from the membrane. At 8-week post-MI, the β2AR-mediated cAMP response was observed at the T-tubules and the sarcolemma (crest). Finally, at 16-week post-MI, the whole cell β2AR-mediated cAMP signal was depressed due to adenylate cyclase dysfunction, while overall Cav-3 levels were significantly increased and a substantial portion of Cav-3 dissociated into the cytosol. Overexpression of JPH2 in failing cells in vitro or AAV9.SERCA2a gene therapy in vivo did not improve β2AR-mediated signal compartmentation or reduce cAMP diffusion. Conclusion Although changes in T-tubule structure and β2AR-mediated cAMP signalling are significant even at 4-week post-MI, progression to the HF phenotype is not linear. At 8-week post-MI the loss of β2AR-mediated cAMP is temporarily reversed. Complete disorganization of β2AR-mediated cAMP signalling due to changes in functional receptor localization and cellular structure occurs at 16-week post-MI.
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Affiliation(s)
- Sophie Schobesberger
- Department of Cardiac Medicine, National Heart and Lung Institute, Imperial College, Du Cane Road, London W12 0NN, UK.,Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Martinistraße, Hamburg D-20246, Germany
| | - Peter Wright
- Department of Cardiac Medicine, National Heart and Lung Institute, Imperial College, Du Cane Road, London W12?0NN, UK
| | - Sergiy Tokar
- Department of Cardiac Medicine, National Heart and Lung Institute, Imperial College, Du Cane Road, London W12?0NN, UK
| | - Anamika Bhargava
- Department of Cardiac Medicine, National Heart and Lung Institute, Imperial College, Du Cane Road, London W12 0NN, UK.,Department of Biotechnology, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram, 502205 Telangana, India
| | - Catherine Mansfield
- Department of Cardiac Medicine, National Heart and Lung Institute, Imperial College, Du Cane Road, London W12?0NN, UK
| | - Alexey V Glukhov
- Department of Cardiac Medicine, National Heart and Lung Institute, Imperial College, Du Cane Road, London W12?0NN, UK
| | - Claire Poulet
- Department of Cardiac Medicine, National Heart and Lung Institute, Imperial College, Du Cane Road, London W12?0NN, UK
| | - Andrey Buzuk
- Department of Cardiac Medicine, National Heart and Lung Institute, Imperial College, Du Cane Road, London W12?0NN, UK
| | - Aron Monszpart
- Department of Computer Science, University College London, Gower Street, London WC1E 6BT, UK
| | - Markus Sikkel
- Department of Cardiac Medicine, National Heart and Lung Institute, Imperial College, Du Cane Road, London W12?0NN, UK
| | - Sian E Harding
- Department of Cardiac Medicine, National Heart and Lung Institute, Imperial College, Du Cane Road, London W12?0NN, UK
| | - Viacheslav O Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Martinistraße, Hamburg D-20246, Germany
| | - Alexander R Lyon
- Department of Cardiac Medicine, National Heart and Lung Institute, Imperial College, Du Cane Road, London W12 0NN, UK.,NIHR Cardiovascular Biomedical Research Unit, Department of Cardiology, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK
| | - Julia Gorelik
- Department of Cardiac Medicine, National Heart and Lung Institute, Imperial College, Du Cane Road, London W12?0NN, UK
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132
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Highly variable contractile performance correlates with myocyte content in trabeculae from failing human hearts. Sci Rep 2018; 8:2957. [PMID: 29440728 PMCID: PMC5811450 DOI: 10.1038/s41598-018-21199-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 01/16/2018] [Indexed: 12/24/2022] Open
Abstract
Heart failure (HF) is defined by compromised contractile function and is associated with changes in excitation-contraction (EC) coupling and cardiomyocyte organisation. Tissue level changes often include fibrosis, while changes within cardiomyocytes often affect structures critical to EC coupling, including the ryanodine receptor (RyR), the associated protein junctophilin-2 (JPH2) and the transverse tubular system architecture. Using a novel approach, we aimed to directly correlate the influence of structural alterations with force development in ventricular trabeculae from failing human hearts. Trabeculae were excised from explanted human hearts in end-stage failure and immediately subjected to force measurements. Following functional experiments, each trabecula was fixed, sectioned and immuno-stained for structural investigations. Peak stress was highly variable between trabeculae from both within and between failing hearts and was strongly correlated with the cross-sectional area occupied by myocytes (MCSA), rather than total trabecula cross-sectional area. At the cellular level, myocytes exhibited extensive microtubule densification which was linked via JPH2 to time-to-peak stress. Trabeculae fractional MCSA variability was much higher than that in adjacent free wall samples. Together, these findings identify several structural parameters implicated in functional impairment in human HF and highlight the structural variability of ventricular trabeculae which should be considered when interpreting functional data.
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133
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Ectopic expression of S28A-mutated Histone H3 modulates longevity, stress resistance and cardiac function in Drosophila. Sci Rep 2018; 8:2940. [PMID: 29440697 PMCID: PMC5811592 DOI: 10.1038/s41598-018-21372-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 02/02/2018] [Indexed: 12/11/2022] Open
Abstract
Histone H3 serine 28 (H3S28) phosphorylation and de-repression of polycomb repressive complex (PRC)-mediated gene regulation is linked to stress conditions in mitotic and post-mitotic cells. To better understand the role of H3S28 phosphorylation in vivo, we studied a Drosophila strain with ectopic expression of constitutively-activated H3S28A, which prevents PRC2 binding at H3S28, thus mimicking H3S28 phosphorylation. H3S28A mutants showed prolonged life span and improved resistance against starvation and paraquat-induced oxidative stress. Morphological and functional analysis of heart tubes revealed smaller luminal areas and thicker walls accompanied by moderately improved cardiac function after acute stress induction. Whole-exome deep gene-sequencing from isolated heart tubes revealed phenotype-corresponding changes in longevity-promoting and myotropic genes. We also found changes in genes controlling mitochondrial biogenesis and respiration. Analysis of mitochondrial respiration from whole flies revealed improved efficacy of ATP production with reduced electron transport-chain activity. Finally, we analyzed posttranslational modification of H3S28 in an experimental heart failure model and observed increased H3S28 phosphorylation levels in HF hearts. Our data establish a critical role of H3S28 phosphorylation in vivo for life span, stress resistance, cardiac and mitochondrial function in Drosophila. These findings may pave the way for H3S28 phosphorylation as a putative target to treat stress-related disorders such as heart failure.
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134
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Yao L, Xie D, Geng L, Shi D, Huang J, Wu Y, Lv F, Liang D, Li L, Liu Y, Li J, Chen YH. REEP5 (Receptor Accessory Protein 5) Acts as a Sarcoplasmic Reticulum Membrane Sculptor to Modulate Cardiac Function. J Am Heart Assoc 2018; 7:JAHA.117.007205. [PMID: 29431104 PMCID: PMC5850239 DOI: 10.1161/jaha.117.007205] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Background Heart failure is a complex syndrome characterized by cardiac contractile impairment with high mortality. Defective intracellular Ca2+ homeostasis is the central cause under this scenario and tightly links to ultrastructural rearrangements of sarcolemmal transverse tubules and the sarcoplasmic reticulum (SR); however, the modulators of the SR architecture remain unknown. The SR has been thought to be a specialized endoplasmic reticulum membrane system. Receptor accessory proteins (REEPs)/DP1/Yop1p are responsible for shaping high‐curvature endoplasmic reticulum tubules. This study aimed to determine the role of REEPs in SR membrane shaping and thus cardiac function. Methods and Results We identified REEP5 (receptor accessory protein 5) as more highly expressed than other REEP members in adult rat ventricular myocardium, and it was downregulated in the failing hearts. Targeted inactivation of REEP5 in rats specially deformed the cardiac SR membrane without affecting transverse tubules, and this was visualized by focused ion beam scanning electron microscopy–based 3‐dimensional reconstruction. Accordingly, simultaneous recordings of depolarization‐induced Ca2+ currents and Ca2+ transients in REEP5‐null cardiomyocytes revealed normal L‐type Ca2+ channel currents but a depressed SR Ca2+ release. Consequently, the excitation–contraction coupling gain of cardiomyocytes and consequent cardiac contractility were compromised. REEP5 deficiency did not alter the expression of major proteins involved in Ca2+ handling in the heart. Conclusions REEP5 modulates cardiac function by shaping the SR. REEP5 defect deforms the SR architecture to depress cardiac contractility. REEP5‐dependent SR shaping might have potential as a therapeutic target for heart failure.
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Affiliation(s)
- Lei Yao
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Duanyang Xie
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Li Geng
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Dan Shi
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Jian Huang
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yufei Wu
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Fei Lv
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Dandan Liang
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Li Li
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Yi Liu
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Jun Li
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China .,Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Yi-Han Chen
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China .,Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
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135
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Chiamvimonvat N, Song LS. LRRC10 (Leucine-Rich Repeat Containing Protein 10) and REEP5 (Receptor Accessory Protein 5) as Novel Regulators of Cardiac Excitation-Contraction Coupling Structure and Function. J Am Heart Assoc 2018; 7:e008260. [PMID: 29431105 PMCID: PMC5850266 DOI: 10.1161/jaha.117.008260] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Nipavan Chiamvimonvat
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis Davis, CA
- Department of Veterans Affairs, Northern California Health Care System, Mather, CA
| | - Long-Sheng Song
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA
- Department of Veterans Affairs, Iowa City Medical Center, Iowa City, IA
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136
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Smith CER, Trafford AW, Caldwell JL, Dibb KM. Physiology and patho-physiology of the cardiac transverse tubular system. CURRENT OPINION IN PHYSIOLOGY 2018. [DOI: 10.1016/j.cophys.2017.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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137
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Schilling JM, Head BP, Patel HH. Caveolins as Regulators of Stress Adaptation. Mol Pharmacol 2018; 93:277-285. [PMID: 29358220 DOI: 10.1124/mol.117.111237] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/19/2018] [Indexed: 12/21/2022] Open
Abstract
Caveolins have been recognized over the past few decades as key regulators of cell physiology. They are ubiquitously expressed and regulate a number of processes that ultimately impact efficiency of cellular processes. Though not critical to life, they are central to stress adaptation in a number of organs. The following review will focus specifically on the role of caveolin in stress adaptation in the heart, brain, and eye, three organs that are susceptible to acute and chronic stress and that show as well declining function with age. In addition, we consider some novel molecular mechanisms that may account for this stress adaptation and also offer potential to drive the future of caveolin research.
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Affiliation(s)
- Jan M Schilling
- Veterans Administration San Diego Healthcare System and Department of Anesthesiology, UCSD School of Medicine, San Diego, California
| | - Brian P Head
- Veterans Administration San Diego Healthcare System and Department of Anesthesiology, UCSD School of Medicine, San Diego, California
| | - Hemal H Patel
- Veterans Administration San Diego Healthcare System and Department of Anesthesiology, UCSD School of Medicine, San Diego, California
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138
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Guo A, Chen R, Wang Y, Huang CK, Chen B, Kutschke W, Hong J, Song LS. Transient activation of PKC results in long-lasting detrimental effects on systolic [Ca 2+] i in cardiomyocytes by altering actin cytoskeletal dynamics and T-tubule integrity. J Mol Cell Cardiol 2018; 115:104-114. [PMID: 29307535 DOI: 10.1016/j.yjmcc.2018.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/18/2017] [Accepted: 01/03/2018] [Indexed: 11/25/2022]
Abstract
AIMS Protein kinase C (PKC) isozymes contribute to the development of heart failure through dysregulation of Ca2+ handling properties and disruption of contractile function in cardiomyocytes. However, the mechanisms by which PKC activation leads to Ca2+ dysfunction are incompletely understood. METHODS AND RESULTS Shortly upon ventricular pressure overload in mice, we detected transient PKC activation that was associated with pulsed actin cytoskeletal rearrangement. In cultured cardiomyocytes, transient activation of PKC promoted long-term deleterious effects on the integrity of the transverse (T)- tubule system, resulting in a significant decrease in the amplitude and increase in the rising kinetics of Ca2+ transients. Treatment with a PKCα/β inhibitor restored the synchronization of Ca2+ transients and maintained T-tubule integrity in cultured cardiomyocytes. Supporting these data, PKCα/β inhibition protected against T-tubule remodeling and cardiac dysfunction in a mouse model of pressure overload-induced heart failure. Mechanistically, transient activation of PKC resulted in biphasic actin cytoskeletal rearrangement, consistent with in vivo observations in the pressure overloaded mouse model. Transient inhibition of actin polymerization or depolymerization resulted in severe T-tubule damage, recapitulating the T-tubule damage induced by PKC activation. Moreover, inhibition of stretch activated channels (SAC) protected against T-tubule remodeling and E-C coupling dysfunction induced by transient PKC activation and actin cytoskeletal rearrangement. CONCLUSIONS These data identify a key mechanistic link between transient PKC activation and long-term Ca2+ handling defects through PKC-induced actin cytoskeletal rearrangement and resultant T-tubule damage.
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Affiliation(s)
- Ang Guo
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
| | - Rong Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200080, China
| | - Yihui Wang
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200080, China
| | - Chun-Kai Huang
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200080, China
| | - Biyi Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - William Kutschke
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Jiang Hong
- Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200080, China
| | - Long-Sheng Song
- Division of Cardiovascular Medicine, Department of Internal Medicine & Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Department of Veterans Affairs Medical Center, Iowa City, IA 52242, USA.
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139
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Song Z, Liu MB, Qu Z. Transverse tubular network structures in the genesis of intracellular calcium alternans and triggered activity in cardiac cells. J Mol Cell Cardiol 2018; 114:288-299. [PMID: 29217432 PMCID: PMC5801147 DOI: 10.1016/j.yjmcc.2017.12.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/31/2017] [Accepted: 12/04/2017] [Indexed: 12/20/2022]
Abstract
RATIONALE The major role of a transverse-tubular (TT) network in a cardiac cell is to facilitate effective excitation-contraction coupling and signaling. The TT network structures are heterogeneous within a single cell, and vary between different types of cells and species. They are also remodeled in cardiac diseases. However, how different TT network structures predispose cardiac cells to arrhythmogenesis remains to be revealed. OBJECTIVE To systematically investigate the roles of TT network structure and the underlying mechanisms in the genesis of intracellular calcium (Ca2+) alternans and triggered activity (TA). METHODS AND RESULTS Based on recent experimental observations, different TT network structures, including uniformly and non-uniformly random TT distributions, were modeled in a cardiac cell model consisting of a three-dimensional network of Ca2+ release units (CRUs). Our simulations showed that both Ca2+ alternans and Ca2+ wave-mediated TA were promoted when the fraction of orphaned CRUs was in an intermediate range, but suppressed in cells exhibiting either well-organized TT networks or low TT densities. Ca2+ alternans and TA could be promoted by low TT densities when the cells were small or the CRU coupling was strong. Both alternans and TA occurred more easily in uniformly random TT networks than in non-uniformly random TT networks. Subcellular spatially discordant Ca2+ alternans was promoted by non-uniformly random TT networks but suppressed by increasing CRU coupling strength. These mechanistic insights provide a holistic understanding of the effects of TT network structure on the susceptibility to arrhythmogenesis. CONCLUSIONS The TT network plays important roles in promoting Ca2+ alternans and TA, and different TT network structures may predispose cardiac cells differently to arrhythmogenesis.
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Affiliation(s)
- Zhen Song
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
| | - Michael B Liu
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Zhilin Qu
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA; Department of Biomathematics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
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140
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Abstract
PURPOSE OF REVIEW Membrane invaginations called t-tubules play an integral role in triggering cardiomyocyte contraction, and their disruption during diseases such as heart failure critically impairs cardiac performance. In this review, we outline the growing understanding of the malleability of t-tubule structure and function, and highlight emerging t-tubule regulators which may be exploited for novel therapies. RECENT FINDINGS New technologies are revealing the nanometer scale organization of t-tubules, and their functional junctions with the sarcoplasmic reticulum called dyads, which generate Ca2+ sparks. Recent data have indicated that the dyadic anchoring protein junctophilin-2, and the membrane-bending protein BIN1 are key regulators of dyadic formation and maintenance. While the underlying signals which control expression and localization of these proteins remain unclear, accumulating data support an important role of myocardial workload. Although t-tubule alterations are believed to be a key cause of heart failure, the plasticity of these structures also creates an opportunity for therapy. Promising recent data suggest that such therapies may specifically target junctophilin-2, BIN1, and/or mechanotransduction.
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141
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Singh JK, Barsegyan V, Bassi N, Marszalec W, Tai S, Mothkur S, Mulla M, Nico E, Shiferaw Y, Aistrup GL, Wasserstrom JA. T-tubule remodeling and increased heterogeneity of calcium release during the progression to heart failure in intact rat ventricle. Physiol Rep 2017; 5:5/24/e13540. [PMID: 29279414 PMCID: PMC5742703 DOI: 10.14814/phy2.13540] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 11/07/2017] [Accepted: 11/10/2017] [Indexed: 01/29/2023] Open
Abstract
A highly organized transverse‐tubule (TT) system is essential to normal Ca2+ cycling and cardiac function. We explored the relationship between the progressive disruption of TTs and resulting Ca2+ cycling during the development of heart failure (HF). Confocal imaging was used to measure Ca2+ transients and 2‐D z‐stack images in left ventricular epicardial myocytes of intact hearts from spontaneously hypertensive rats (SHR) and Wistar‐Kyoto control rats. TT organization was measured as the organizational index (OI) derived from a fast Fourier transform of TT organization. We found little decrease in the synchrony of Ca2+ release with TT loss until TT remodeling was severe, suggesting a TT “reserve” characterized by a wide range of TT remodeling with little effect on synchrony of release but beyond which variability in release shows an accelerating sensitivity to TT loss. To explain this observation, we applied a computational model of spatially distributed Ca2+ signaling units to investigate the relationship between OI and excitation‐contraction coupling. Our model showed that release heterogeneity exhibits a nonlinear relationship on both the spatial distribution of release units and the separation between L‐type Ca2+ channels and ryanodine receptors. Our results demonstrate a unique relationship between the synchrony of Ca2+ release and TT organization in myocytes of intact rat ventricle that may contribute to both the compensated and decompensated phases of heart failure.
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Affiliation(s)
- Jasleen K Singh
- Department of Medicine (Cardiology), The Feinberg Cardiovascular Research Institute Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Varderes Barsegyan
- Department of Physics and Astronomy, California State University, Northridge, California
| | - Nikhil Bassi
- Department of Medicine (Cardiology), The Feinberg Cardiovascular Research Institute Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - William Marszalec
- Department of Medicine (Cardiology), The Feinberg Cardiovascular Research Institute Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Shannon Tai
- Department of Medicine (Cardiology), The Feinberg Cardiovascular Research Institute Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Shruthi Mothkur
- Department of Medicine (Cardiology), The Feinberg Cardiovascular Research Institute Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Maaz Mulla
- Department of Medicine (Cardiology), The Feinberg Cardiovascular Research Institute Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Elsa Nico
- Department of Medicine (Cardiology), The Feinberg Cardiovascular Research Institute Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Yohannes Shiferaw
- Department of Physics and Astronomy, California State University, Northridge, California
| | - Gary L Aistrup
- Department of Medicine (Cardiology), The Feinberg Cardiovascular Research Institute Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - John Andrew Wasserstrom
- Department of Medicine (Cardiology), The Feinberg Cardiovascular Research Institute Northwestern University Feinberg School of Medicine, Chicago, Illinois
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142
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Regulation of microdomain voltage-gated L-type calcium channels in cardiac health and disease. CURRENT OPINION IN PHYSIOLOGY 2017; 2:13-18. [PMID: 29963649 DOI: 10.1016/j.cophys.2017.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cav1.2 channels in the heart mediate excitation-contraction (E-C) coupling; tune cardiac excitability; and regulate gene expression. In ventricular myocytes, CaV1.2 channels are predominantly located in t-tubules where they are in proximity to ryanodine receptors to trigger cardiac E-C coupling. A subset of ventricular CaV1.2 channels existing on the surface sarcolemma, including in caveolae, have less well-defined functions. Cardiac CaV1.2 channels are famously up-regulated by protein kinase A as a component of the 'fight-or-flight' response. The molecular details of how this kinase regulates cardiac CaV1.2 channels are controversial and under intensive study. Here, we critically review recent work addressing the putative functions of microdomain cardiac CaV1.2 channels, and their regulation by distinct kinases in health and disease.
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143
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Tian Q, Kaestner L, Schröder L, Guo J, Lipp P. An adaptation of astronomical image processing enables characterization and functional 3D mapping of individual sites of excitation-contraction coupling in rat cardiac muscle. eLife 2017; 6:30425. [PMID: 29135437 PMCID: PMC5703646 DOI: 10.7554/elife.30425] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 11/03/2017] [Indexed: 01/06/2023] Open
Abstract
In beating cardiomyocytes, synchronized localized Ca2+ transients from thousands of active excitation-contraction coupling sites (ECC couplons) comprising plasma and sarcoplasmic reticulum membrane calcium channels are important determinants of the heart's performance. Nevertheless, our knowledge about the properties of ECC couplons is limited by the lack of appropriate experimental and analysis strategies. We designed CaCLEAN to untangle the fundamental characteristics of ECC couplons by combining the astronomer's CLEAN algorithm with known properties of calcium diffusion. CaCLEAN empowers the investigation of fundamental properties of ECC couplons in beating cardiomyocytes without pharmacological interventions. Upon examining individual ECC couplons at the nanoscopic level, we reveal their roles in the negative amplitude-frequency relationship and in β-adrenergic stimulation, including decreasing and increasing firing reliability, respectively. CaCLEAN combined with 3D confocal imaging of beating cardiomyocytes provides a functional 3D map of active ECC couplons (on average, 17,000 per myocyte). CaCLEAN will further enlighten the ECC-couplon-remodelling processes that underlie cardiac diseases.
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Affiliation(s)
- Qinghai Tian
- Institute for Molecular Cell Biology, Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, Homburg, Germany
| | - Lars Kaestner
- Institute for Molecular Cell Biology, Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, Homburg, Germany
| | - Laura Schröder
- Institute for Molecular Cell Biology, Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, Homburg, Germany
| | - Jia Guo
- Institute for Molecular Cell Biology, Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, Homburg, Germany
| | - Peter Lipp
- Institute for Molecular Cell Biology, Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, Homburg, Germany
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144
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Vela-Guajardo JE, Pérez-Treviño P, Rivera-Álvarez I, González-Mondellini FA, Altamirano J, García N. The 8-oxo-deoxyguanosine glycosylase increases its migration to mitochondria in compensated cardiac hypertrophy. ACTA ACUST UNITED AC 2017; 11:660-672. [PMID: 28882450 DOI: 10.1016/j.jash.2017.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/30/2017] [Accepted: 08/15/2017] [Indexed: 11/19/2022]
Abstract
Cardiac hypertrophy is a compensatory mechanism maladapted because it presents an increase in the oxidative stress which could be associated with the development of the heart failure. A mechanism proposed is by mitochondrial DNA (mtDNA) oxidation, which evolved to a vicious cycle because of the synthesis of proteins encoded in the genome is committed. Therefore, the aim of the present work was to evaluate the mtDNA damage and enzyme repairing the 8-oxo-deoxyguanosine glycosylase mitochondrial isoform 1-2a (OGG1-2a) in the early stage of compensated cardiac hypertrophy induced by abdominal aortic constriction (AAC). Results showed that after 6 weeks of AAC, hearts presented a compensated hypertrophy (22%), with an increase in the cell volume (35%), mitochondrial mass (12%), and mitochondrial membrane potential (94%). However, the increase of oxidative stress did not affect mtDNA most probably because OGG1-2a was found to increase 3.2 times in the mitochondrial fraction. Besides, mitochondrial function was not altered by the cardiac hypertrophy condition but in vitro mitochondria from AAC heart showed an increased sensibility to stress induced by the high Ca2+ concentration. The increase in the oxidative stress in compensated cardiac hypertrophy induced the OGG1-2a migration to mitochondria to repair mtDNA oxidation, as a mechanism that allows maintaining the cardiac function in the compensatory stage.
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Affiliation(s)
- Jorge E Vela-Guajardo
- Medicina Cardiovascular y Metabolómica, Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, San Pedro Garza García, Nuevo León, México
| | - Perla Pérez-Treviño
- Medicina Cardiovascular y Metabolómica, Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, San Pedro Garza García, Nuevo León, México
| | - Irais Rivera-Álvarez
- Medicina Cardiovascular y Metabolómica, Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, San Pedro Garza García, Nuevo León, México
| | - Fabio A González-Mondellini
- Medicina Cardiovascular y Metabolómica, Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, San Pedro Garza García, Nuevo León, México
| | - Julio Altamirano
- Medicina Cardiovascular y Metabolómica, Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, San Pedro Garza García, Nuevo León, México
| | - Noemí García
- Medicina Cardiovascular y Metabolómica, Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, San Pedro Garza García, Nuevo León, México.
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145
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Zhang C, Chen B, Wang Y, Guo A, Tang Y, Khataei T, Shi Y, Kutschke WJ, Zimmerman K, Weiss RM, Liu J, Benson CJ, Hong J, Ma J, Song LS. MG53 is dispensable for T-tubule maturation but critical for maintaining T-tubule integrity following cardiac stress. J Mol Cell Cardiol 2017; 112:123-130. [PMID: 28822805 DOI: 10.1016/j.yjmcc.2017.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 08/13/2017] [Accepted: 08/14/2017] [Indexed: 01/28/2023]
Abstract
The cardiac transverse (T)-tubule membrane system is the safeguard for cardiac function and undergoes dramatic remodeling in response to cardiac stress. However, the mechanism by which cardiomyocytes repair damaged T-tubule network remains unclear. In the present study, we tested the hypothesis that MG53, a muscle-specific membrane repair protein, antagonizes T-tubule damage to protect against maladaptive remodeling and thereby loss of excitation-contraction coupling and cardiac function. Using MG53-knockout (MG53-KO) mice, we first established that deficiency of MG53 had no impact on maturation of the T-tubule network in developing hearts. Additionally, MG53 ablation did not influence T-tubule integrity in unstressed adult hearts as late as 10months of age. Following left ventricular pressure overload-induced cardiac stress, MG53 protein levels were increased by approximately three-fold in wild-type mice, indicating that pathological stress induces a significant upregulation of MG53. MG53-deficient mice had worsened T-tubule disruption and pronounced dysregulation of Ca2+ handling properties, including decreased Ca2+ transient amplitude and prolonged time to peak and decay. Moreover, MG53 deficiency exacerbated cardiac hypertrophy and dysfunction and decreased survival following cardiac stress. Our data suggest MG53 is not required for T-tubule development and maintenance in normal physiology. However, MG53 is essential to preserve T-tubule integrity and thereby Ca2+ handling properties and cardiac function under pathological cardiac stress.
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Affiliation(s)
- Caimei Zhang
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Biyi Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Yihui Wang
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Shanghai First People's Hospital, Shanghai Jiaotong University, Shanghai 200080, China
| | - Ang Guo
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Yiqun Tang
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Department of Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Tahsin Khataei
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Yun Shi
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - William J Kutschke
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Kathy Zimmerman
- Department of Veterans Affairs Medical Center, Iowa City, IA 52242, USA
| | - Robert M Weiss
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Jie Liu
- Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Christopher J Benson
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Department of Veterans Affairs Medical Center, Iowa City, IA 52242, USA
| | - Jiang Hong
- Shanghai First People's Hospital, Shanghai Jiaotong University, Shanghai 200080, China
| | - Jianjie Ma
- Department of Surgery, Ohio State University Medical Center, Columbus, OH 43212, USA
| | - Long-Sheng Song
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Department of Veterans Affairs Medical Center, Iowa City, IA 52242, USA.
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146
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The ESCRT-III pathway facilitates cardiomyocyte release of cBIN1-containing microparticles. PLoS Biol 2017; 15:e2002354. [PMID: 28806752 PMCID: PMC5570487 DOI: 10.1371/journal.pbio.2002354] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 08/24/2017] [Accepted: 07/26/2017] [Indexed: 12/17/2022] Open
Abstract
Microparticles (MPs) are cell–cell communication vesicles derived from the cell surface plasma membrane, although they are not known to originate from cardiac ventricular muscle. In ventricular cardiomyocytes, the membrane deformation protein cardiac bridging integrator 1 (cBIN1 or BIN1+13+17) creates transverse-tubule (t-tubule) membrane microfolds, which facilitate ion channel trafficking and modulate local ionic concentrations. The microfold-generated microdomains continuously reorganize, adapting in response to stress to modulate the calcium signaling apparatus. We explored the possibility that cBIN1-microfolds are externally released from cardiomyocytes. Using electron microscopy imaging with immunogold labeling, we found in mouse plasma that cBIN1 exists in membrane vesicles about 200 nm in size, which is consistent with the size of MPs. In mice with cardiac-specific heterozygous Bin1 deletion, flow cytometry identified 47% less cBIN1-MPs in plasma, supporting cardiac origin. Cardiac release was also evidenced by the detection of cBIN1-MPs in medium bathing a pure population of isolated adult mouse cardiomyocytes. In human plasma, osmotic shock increased cBIN1 detection by enzyme-linked immunosorbent assay (ELISA), and cBIN1 level decreased in humans with heart failure, a condition with reduced cardiac muscle cBIN1, both of which support cBIN1 release in MPs from human hearts. Exploring putative mechanisms of MP release, we found that the membrane fission complex endosomal sorting complexes required for transport (ESCRT)-III subunit charged multivesicular body protein 4B (CHMP4B) colocalizes and coimmunoprecipitates with cBIN1, an interaction enhanced by actin stabilization. In HeLa cells with cBIN1 overexpression, knockdown of CHMP4B reduced the release of cBIN1-MPs. Using truncation mutants, we identified that the N-terminal BAR (N-BAR) domain in cBIN1 is required for CHMP4B binding and MP release. This study links the BAR protein superfamily to the ESCRT pathway for MP biogenesis in mammalian cardiac ventricular cells, identifying elements of a pathway by which cytoplasmic cBIN1 is released into blood. Microparticles are small vesicles generated from the cell surface membrane and externally released for communication with other cells. We now show that heart ventricular muscle cells, which form the main pumping chambers of the heart, release microparticles in both mouse and human. Ventricular microparticles arise from surface membrane microdomains organized by cardiac bridging integrator 1 (cBIN1), a membrane deformation protein that has been shown to be reduced during human heart failure. Here we identify microparticles containing cBIN1 in blood, which were reduced in mutant mice lacking heart cBIN1 expression. Furthermore, the process leading to microparticle release involves the recruitment of CHMP4B protein to snip the cBIN1 membrane. In humans, cBIN1 is present in blood and within microparticles. Upon osmotic shock, human microparticles burst, allowing for the quantification of cBIN1 in plasma by enzyme-linked immunosorbent assay (ELISA). The measured cBIN1 level was greatly reduced in patients with heart failure. Thus, we introduce the biology for a new blood-based diagnostic tool that can assess cardiac muscle health and identify failing heart in human patients.
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147
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Hall DD, Ponce JM, Chen B, Spitler KM, Alexia A, Oudit GY, Song LS, Grueter CE. Ectopic expression of Cdk8 induces eccentric hypertrophy and heart failure. JCI Insight 2017; 2:92476. [PMID: 28768905 DOI: 10.1172/jci.insight.92476] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 06/20/2017] [Indexed: 11/17/2022] Open
Abstract
Widespread changes in cardiac gene expression occur during heart failure, yet the mechanisms responsible for coordinating these changes remain poorly understood. The Mediator complex represents a nodal point for modulating transcription by bridging chromatin-bound transcription factors with RNA polymerase II activity; it is reversibly regulated by its cyclin-dependent kinase 8 (Cdk8) kinase submodule. Here, we identified increased Cdk8 protein expression in human failing heart explants and determined the consequence of this increase in cardiac-specific Cdk8-expressing mice. Transgenic Cdk8 overexpression resulted in progressive dilated cardiomyopathy, heart failure, and premature lethality. Prior to functional decline, left ventricular cardiomyocytes were dramatically elongated, with disorganized transverse tubules and dysfunctional calcium handling. RNA sequencing results showed that myofilament gene isoforms not typically expressed in adult cardiomyocytes were enriched, while oxidative phosphorylation and fatty acid biosynthesis genes were downregulated. Interestingly, candidate upstream transcription factor expression levels and MAPK signaling pathways thought to determine cardiomyocyte size remained relatively unaffected, suggesting that Cdk8 functions within a novel growth regulatory pathway. Our findings show that manipulating cardiac gene expression through increased Cdk8 levels is detrimental to the heart by establishing a transcriptional program that induces pathological remodeling and eccentric hypertrophy culminating in heart failure.
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Affiliation(s)
- Duane D Hall
- Department of Internal Medicine, Division of Cardiovascular Medicine, Francois M. Abboud Cardiovascular Research Center, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Jessica M Ponce
- Department of Internal Medicine, Division of Cardiovascular Medicine, Francois M. Abboud Cardiovascular Research Center, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Biyi Chen
- Department of Internal Medicine, Division of Cardiovascular Medicine, Francois M. Abboud Cardiovascular Research Center, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Kathryn M Spitler
- Department of Internal Medicine, Division of Cardiovascular Medicine, Francois M. Abboud Cardiovascular Research Center, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Adrianne Alexia
- Department of Internal Medicine, Division of Cardiovascular Medicine, Francois M. Abboud Cardiovascular Research Center, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Gavin Y Oudit
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Long-Sheng Song
- Department of Internal Medicine, Division of Cardiovascular Medicine, Francois M. Abboud Cardiovascular Research Center, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Chad E Grueter
- Department of Internal Medicine, Division of Cardiovascular Medicine, Francois M. Abboud Cardiovascular Research Center, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
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148
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Ferrantini C, Coppini R, Pioner JM, Gentile F, Tosi B, Mazzoni L, Scellini B, Piroddi N, Laurino A, Santini L, Spinelli V, Sacconi L, De Tombe P, Moore R, Tardiff J, Mugelli A, Olivotto I, Cerbai E, Tesi C, Poggesi C. Pathogenesis of Hypertrophic Cardiomyopathy is Mutation Rather Than Disease Specific: A Comparison of the Cardiac Troponin T E163R and R92Q Mouse Models. J Am Heart Assoc 2017; 6:JAHA.116.005407. [PMID: 28735292 PMCID: PMC5586279 DOI: 10.1161/jaha.116.005407] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background In cardiomyocytes from patients with hypertrophic cardiomyopathy, mechanical dysfunction and arrhythmogenicity are caused by mutation‐driven changes in myofilament function combined with excitation‐contraction (E‐C) coupling abnormalities related to adverse remodeling. Whether myofilament or E‐C coupling alterations are more relevant in disease development is unknown. Here, we aim to investigate whether the relative roles of myofilament dysfunction and E‐C coupling remodeling in determining the hypertrophic cardiomyopathy phenotype are mutation specific. Methods and Results Two hypertrophic cardiomyopathy mouse models carrying the R92Q and the E163R TNNT2 mutations were investigated. Echocardiography showed left ventricular hypertrophy, enhanced contractility, and diastolic dysfunction in both models; however, these phenotypes were more pronounced in the R92Q mice. Both E163R and R92Q trabeculae showed prolonged twitch relaxation and increased occurrence of premature beats. In E163R ventricular myofibrils or skinned trabeculae, relaxation following Ca2+ removal was prolonged; resting tension and resting ATPase were higher; and isometric ATPase at maximal Ca2+ activation, the energy cost of tension generation, and myofilament Ca2+ sensitivity were increased compared with that in wild‐type mice. No sarcomeric changes were observed in R92Q versus wild‐type mice, except for a large increase in myofilament Ca2+ sensitivity. In R92Q myocardium, we found a blunted response to inotropic interventions, slower decay of Ca2+ transients, reduced SERCA function, and increased Ca2+/calmodulin kinase II activity. Contrarily, secondary alterations of E‐C coupling and signaling were minimal in E163R myocardium. Conclusions In E163R models, mutation‐driven myofilament abnormalities directly cause myocardial dysfunction. In R92Q, diastolic dysfunction and arrhythmogenicity are mediated by profound cardiomyocyte signaling and E‐C coupling changes. Similar hypertrophic cardiomyopathy phenotypes can be generated through different pathways, implying different strategies for a precision medicine approach to treatment.
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MESH Headings
- Animals
- Calcium Signaling
- Calcium-Calmodulin-Dependent Protein Kinases/metabolism
- Cardiomyopathy, Hypertrophic/diagnostic imaging
- Cardiomyopathy, Hypertrophic/genetics
- Cardiomyopathy, Hypertrophic/metabolism
- Cardiomyopathy, Hypertrophic/physiopathology
- Disease Models, Animal
- Excitation Contraction Coupling
- Fibrosis
- Genetic Markers
- Genetic Predisposition to Disease
- Hypertrophy, Left Ventricular/diagnostic imaging
- Hypertrophy, Left Ventricular/genetics
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/physiopathology
- Male
- Mice, Inbred C57BL
- Mice, Transgenic
- Mutation
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Myofibrils/metabolism
- Myofibrils/pathology
- Phenotype
- Sarcoplasmic Reticulum Calcium-Transporting ATPases/metabolism
- Troponin T/genetics
- Ventricular Dysfunction, Left/diagnostic imaging
- Ventricular Dysfunction, Left/genetics
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Function, Left
- Ventricular Remodeling
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Affiliation(s)
- Cecilia Ferrantini
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | | | - Josè Manuel Pioner
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Francesca Gentile
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Benedetta Tosi
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Luca Mazzoni
- Department of NeuroFarBa, University of Florence, Italy
| | - Beatrice Scellini
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Nicoletta Piroddi
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | | | | | | | - Leonardo Sacconi
- LENS, University of Florence & National Institute of Optics (INO-CNR), Florence, Italy
| | - Pieter De Tombe
- Loyola University Medical Center Department of Physiology, Chicago, IL
| | | | | | - Alessandro Mugelli
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | | | | | - Chiara Tesi
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Italy
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149
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Correll RN, Lynch JM, Schips TG, Prasad V, York AJ, Sargent MA, Brochet DXP, Ma J, Molkentin JD. Mitsugumin 29 regulates t-tubule architecture in the failing heart. Sci Rep 2017; 7:5328. [PMID: 28706255 PMCID: PMC5509714 DOI: 10.1038/s41598-017-05284-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 05/25/2017] [Indexed: 11/09/2022] Open
Abstract
Transverse tubules (t-tubules) are uniquely-adapted membrane invaginations in cardiac myocytes that facilitate the synchronous release of Ca2+ from internal stores and subsequent myofilament contraction, although these structures become disorganized and rarefied in heart failure. We previously observed that mitsugumin 29 (Mg29), an important t-tubule organizing protein in skeletal muscle, was induced in the mouse heart for the first time during dilated cardiomyopathy with heart failure. Here we generated cardiac-specific transgenic mice expressing Mg29 to model this observed induction in the failing heart. Interestingly, expression of Mg29 in the hearts of Csrp3 null mice (encoding muscle LIM protein, MLP) partially restored t-tubule structure and preserved cardiac function as measured by invasive hemodynamics, without altering Ca2+ spark frequency. Conversely, gene-deleted mice lacking both Mg29 and MLP protein showed a further reduction in t-tubule organization and accelerated heart failure. Thus, induction of Mg29 in the failing heart is a compensatory response that directly counteracts the well-characterized loss of t-tubule complexity and reduced expression of anchoring proteins such as junctophilin-2 (Jph2) that normally occur in this disease. Moreover, preservation of t-tubule structure by Mg29 induction significantly increases the function of the failing heart.
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Affiliation(s)
- Robert N Correll
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229, USA
| | - Jeffrey M Lynch
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229, USA
| | - Tobias G Schips
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229, USA
| | - Vikram Prasad
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229, USA
| | - Allen J York
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229, USA
| | - Michelle A Sargent
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229, USA
| | - Didier X P Brochet
- Department of Physiology, University of Maryland School of Medicine and Center for Biomedical Engineering and Technology (BioMET), Baltimore, Maryland, 21201, USA
| | - Jianjie Ma
- Department of Surgery, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Jeffery D Molkentin
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229, USA. .,Howard Hughes Medical Institute, Cincinnati, Ohio, 45229, USA.
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150
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Seidel T, Sankarankutty AC, Sachse FB. Remodeling of the transverse tubular system after myocardial infarction in rabbit correlates with local fibrosis: A potential role of biomechanics. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:302-314. [PMID: 28709857 DOI: 10.1016/j.pbiomolbio.2017.07.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 07/07/2017] [Accepted: 07/10/2017] [Indexed: 02/03/2023]
Abstract
The transverse tubular system (t-system) of ventricular cardiomyocytes is essential for efficient excitation-contraction coupling. In cardiac diseases, such as heart failure, remodeling of the t-system contributes to reduced cardiac contractility. However, mechanisms of t-system remodeling are incompletely understood. Prior studies suggested an association with altered cardiac biomechanics and gene expression in disease. Since fibrosis may alter tissue biomechanics, we investigated the local microscopic association of t-system remodeling with fibrosis in a rabbit model of myocardial infarction (MI). Biopsies were taken from the MI border zone of 6 infarcted hearts and from 6 control hearts. Using confocal microscopy and automated image analysis, we quantified t-system integrity (ITT) and the local fraction of extracellular matrix (fECM). In control, fECM was 18 ± 0.3%. ITT was high and homogeneous (0.07 ± 0.006), and did not correlate with fECM (R2 = 0.05 ± 0.02). The MI border zone exhibited increased fECM within 3 mm from the infarct scar (30 ± 3.5%, p < 0.01 vs control), indicating fibrosis. Myocytes in the MI border zone exhibited significant t-system remodeling, with dilated, sheet-like components, resulting in low ITT (0.03 ± 0.008, p < 0.001 vs control). While both fECM and t-system remodeling decreased with infarct distance, ITT correlated better with decreasing fECM (R2 = 0.44) than with infarct distance (R2 = 0.24, p < 0.05). Our results show that t-system remodeling in the rabbit MI border zone resembles a phenotype previously described in human heart failure. T-system remodeling correlated with the amount of local fibrosis, which is known to stiffen cardiac tissue, but was not found in regions without fibrosis. Thus, locally altered tissue mechanics may contribute to t-system remodeling.
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Affiliation(s)
- T Seidel
- Institute for Cellular and Molecular Physiology, University of Erlangen-Nuremberg, Erlangen, Germany; Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, USA.
| | - A C Sankarankutty
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, USA; Department of Bioengineering, University of Utah, Salt Lake City, USA
| | - F B Sachse
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, USA; Department of Bioengineering, University of Utah, Salt Lake City, USA.
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