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Bhattacharyya S, Pucadyil TJ. Dynamics of membrane tubulation coupled with fission by a two-component module. Proc Natl Acad Sci U S A 2024; 121:e2402180121. [PMID: 38717859 PMCID: PMC11098101 DOI: 10.1073/pnas.2402180121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 04/05/2024] [Indexed: 05/18/2024] Open
Abstract
Membrane tubulation coupled with fission (MTCF) is a widespread phenomenon but mechanisms for their coordination remain unclear, partly because of the lack of assays to monitor dynamics of membrane tubulation and subsequent fission. Using polymer cushioned bilayer islands, we analyze the membrane tubulator Bridging Integrator 1 (BIN1) mixed with the fission catalyst dynamin2 (Dyn2). Our results reveal this mixture to constitute a minimal two-component module that demonstrates MTCF. MTCF is an emergent property and arises because BIN1 facilitates recruitment but inhibits membrane binding of Dyn2 in a dose-dependent manner. MTCF is therefore apparent only at high Dyn2 to BIN1 ratios. Because of their mutual involvement in T-tubules biogenesis, mutations in BIN1 and Dyn2 are associated with centronuclear myopathies and our analysis links the pathology with aberrant MTCF. Together, our results establish cushioned bilayer islands as a facile template for the analysis of membrane tubulation and inform of mechanisms that coordinate MTCF.
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Affiliation(s)
- Soumya Bhattacharyya
- Indian Institute of Science Education and Research, Pashan, Pune411008, Maharashtra, India
| | - Thomas J. Pucadyil
- Indian Institute of Science Education and Research, Pashan, Pune411008, Maharashtra, India
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2
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Kraft AE, Bork NI, Subramanian H, Pavlaki N, Failla AV, Zobiak B, Conti M, Nikolaev VO. Phosphodiesterases 4B and 4D Differentially Regulate cAMP Signaling in Calcium Handling Microdomains of Mouse Hearts. Cells 2024; 13:476. [PMID: 38534320 DOI: 10.3390/cells13060476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 03/05/2024] [Accepted: 03/06/2024] [Indexed: 03/28/2024] Open
Abstract
The ubiquitous second messenger 3',5'-cyclic adenosine monophosphate (cAMP) regulates cardiac excitation-contraction coupling (ECC) by signaling in discrete subcellular microdomains. Phosphodiesterase subfamilies 4B and 4D are critically involved in the regulation of cAMP signaling in mammalian cardiomyocytes. Alterations of PDE4 activity in human hearts has been shown to result in arrhythmias and heart failure. Here, we sought to systematically investigate specific roles of PDE4B and PDE4D in the regulation of cAMP dynamics in three distinct subcellular microdomains, one of them located at the caveolin-rich plasma membrane which harbors the L-type calcium channels (LTCCs), as well as at two sarco/endoplasmic reticulum (SR) microdomains centered around SR Ca2+-ATPase (SERCA2a) and cardiac ryanodine receptor type 2 (RyR2). Transgenic mice expressing Förster Resonance Energy Transfer (FRET)-based cAMP-specific biosensors targeted to caveolin-rich plasma membrane, SERCA2a and RyR2 microdomains were crossed to PDE4B-KO and PDE4D-KO mice. Direct analysis of the specific effects of both PDE4 subfamilies on local cAMP dynamics was performed using FRET imaging. Our data demonstrate that all three microdomains are differentially regulated by these PDE4 subfamilies. Whereas both are involved in cAMP regulation at the caveolin-rich plasma membrane, there are clearly two distinct cAMP microdomains at the SR formed around RyR2 and SERCA2a, which are preferentially controlled by PDE4B and PDE4D, respectively. This correlates with local cAMP-dependent protein kinase (PKA) substrate phosphorylation and arrhythmia susceptibility. Immunoprecipitation assays confirmed that PDE4B is associated with RyR2 along with PDE4D. Stimulated Emission Depletion (STED) microscopy of immunostained cardiomyocytes suggested possible co-localization of PDE4B with both sarcolemmal and RyR2 microdomains. In conclusion, our functional approach could show that both PDE4B and PDE4D can differentially regulate cardiac cAMP microdomains associated with calcium homeostasis. PDE4B controls cAMP dynamics in both caveolin-rich plasma membrane and RyR2 vicinity. Interestingly, PDE4B is the major regulator of the RyR2 microdomain, as opposed to SERCA2a vicinity, which is predominantly under PDE4D control, suggesting a more complex regulatory pattern than previously thought, with multiple PDEs acting at the same location.
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Affiliation(s)
- Axel E Kraft
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Nadja I Bork
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Hariharan Subramanian
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Nikoleta Pavlaki
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
| | - Antonio V Failla
- UKE Microscopy Imaging Facility (UMIF), University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Bernd Zobiak
- UKE Microscopy Imaging Facility (UMIF), University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Marco Conti
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Department of Obstetrics, Gynecology, and Reproductive Sciences, Center for Reproductive Sciences, University of California, San Francisco, CA 94143, USA
| | - Viacheslav O Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany
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Scardigli M, Pásek M, Santini L, Palandri C, Conti E, Crocini C, Campione M, Loew LM, de Vries AAF, Pijnappels DA, Pavone FS, Poggesi C, Cerbai E, Coppini R, Kohl P, Ferrantini C, Sacconi L. Optogenetic confirmation of transverse-tubular membrane excitability in intact cardiac myocytes. J Physiol 2024; 602:791-808. [PMID: 38348881 DOI: 10.1113/jp285202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 01/17/2024] [Indexed: 03/09/2024] Open
Abstract
T-tubules (TT) form a complex network of sarcolemmal membrane invaginations, essential for well-co-ordinated excitation-contraction coupling (ECC) and thus homogeneous mechanical activation of cardiomyocytes. ECC is initiated by rapid depolarization of the sarcolemmal membrane. Whether TT membrane depolarization is active (local generation of action potentials; AP) or passive (following depolarization of the outer cell surface sarcolemma; SS) has not been experimentally validated in cardiomyocytes. Based on the assessment of ion flux pathways needed for AP generation, we hypothesize that TT are excitable. We therefore explored TT excitability experimentally, using an all-optical approach to stimulate and record trans-membrane potential changes in TT that were structurally disconnected, and hence electrically insulated, from the SS membrane by transient osmotic shock. Our results establish that cardiomyocyte TT can generate AP. These AP show electrical features that differ substantially from those observed in SS, consistent with differences in the density of ion channels and transporters in the two different membrane domains. We propose that TT-generated AP represent a safety mechanism for TT AP propagation and ECC, which may be particularly relevant in pathophysiological settings where morpho-functional changes reduce the electrical connectivity between SS and TT membranes. KEY POINTS: Cardiomyocytes are characterized by a complex network of membrane invaginations (the T-tubular system) that propagate action potentials to the core of the cell, causing uniform excitation-contraction coupling across the cell. In the present study, we investigated whether the T-tubular system is able to generate action potentials autonomously, rather than following depolarization of the outer cell surface sarcolemma. For this purpose, we developed a fully optical platform to probe and manipulate the electrical dynamics of subcellular membrane domains. Our findings demonstrate that T-tubules are intrinsically excitable, revealing distinct characteristics of self-generated T-tubular action potentials. This active electrical capability would protect cells from voltage drops potentially occurring within the T-tubular network.
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Affiliation(s)
- Marina Scardigli
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Michal Pásek
- Institute of Thermomechanics, Czech Academy of Science, Prague, Czech Republic
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Lorenzo Santini
- Department of Neurology, Psychology, Drug Sciences and Child Health, University of Florence, Florence, Italy
| | - Chiara Palandri
- Department of Neurology, Psychology, Drug Sciences and Child Health, University of Florence, Florence, Italy
| | - Emilia Conti
- European Laboratory for Non-Linear Spectroscopy - LENS, Sesto Fiorentino, Italy
- Neuroscience Institute, National Research Council, Pisa, Italy
| | - Claudia Crocini
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
- Max Rubner Center for Cardiovascular Metabolic Renal Research (MRC), Deutsches Herzzentrum der Charité (DHZC), Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Marina Campione
- Institute of Neuroscience (IN-CNR) and Department of Biomedical Science, University of Padua, Padua, Italy
| | - Leslie M Loew
- Center for Cell Analysis and Modeling, University of Connecticut, Farmington, CT, USA
| | - Antoine A F de Vries
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Daniël A Pijnappels
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Francesco S Pavone
- European Laboratory for Non-Linear Spectroscopy - LENS, Sesto Fiorentino, Italy
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Elisabetta Cerbai
- Department of Neurology, Psychology, Drug Sciences and Child Health, University of Florence, Florence, Italy
- European Laboratory for Non-Linear Spectroscopy - LENS, Sesto Fiorentino, Italy
| | - Raffaele Coppini
- Department of Neurology, Psychology, Drug Sciences and Child Health, University of Florence, Florence, Italy
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center and Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Cecilia Ferrantini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Leonardo Sacconi
- European Laboratory for Non-Linear Spectroscopy - LENS, Sesto Fiorentino, Italy
- Institute for Experimental Cardiovascular Medicine, University Heart Center and Medical Faculty, University of Freiburg, Freiburg, Germany
- Institute of Clinical Physiology, National Research Council (IFC-CNR), Florence, Italy
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Kwan Z, Paulose Nadappuram B, Leung MM, Mohagaonkar S, Li A, Amaradasa KS, Chen J, Rothery S, Kibreab I, Fu J, Sanchez-Alonso JL, Mansfield CA, Subramanian H, Kondrashov A, Wright PT, Swiatlowska P, Nikolaev VO, Wojciak-Stothard B, Ivanov AP, Edel JB, Gorelik J. Microtubule-Mediated Regulation of β 2AR Translation and Function in Failing Hearts. Circ Res 2023; 133:944-958. [PMID: 37869877 PMCID: PMC10635332 DOI: 10.1161/circresaha.123.323174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 10/11/2023] [Accepted: 10/11/2023] [Indexed: 10/24/2023]
Abstract
BACKGROUND β1AR (beta-1 adrenergic receptor) and β2AR (beta-2 adrenergic receptor)-mediated cyclic adenosine monophosphate signaling has distinct effects on cardiac function and heart failure progression. However, the mechanism regulating spatial localization and functional compartmentation of cardiac β-ARs remains elusive. Emerging evidence suggests that microtubule-dependent trafficking of mRNP (messenger ribonucleoprotein) and localized protein translation modulates protein compartmentation in cardiomyocytes. We hypothesized that β-AR compartmentation in cardiomyocytes is accomplished by selective trafficking of its mRNAs and localized translation. METHODS The localization pattern of β-AR mRNA was investigated using single molecule fluorescence in situ hybridization and subcellular nanobiopsy in rat cardiomyocytes. The role of microtubule on β-AR mRNA localization was studied using vinblastine, and its effect on receptor localization and function was evaluated with immunofluorescent and high-throughput Förster resonance energy transfer microscopy. An mRNA protein co-detection assay identified plausible β-AR translation sites in cardiomyocytes. The mechanism by which β-AR mRNA is redistributed post-heart failure was elucidated by single molecule fluorescence in situ hybridization, nanobiopsy, and high-throughput Förster resonance energy transfer microscopy on 16 weeks post-myocardial infarction and detubulated cardiomyocytes. RESULTS β1AR and β2AR mRNAs show differential localization in cardiomyocytes, with β1AR found in the perinuclear region and β2AR showing diffuse distribution throughout the cell. Disruption of microtubules induces a shift of β2AR transcripts toward the perinuclear region. The close proximity between β2AR transcripts and translated proteins suggests that the translation process occurs in specialized, precisely defined cellular compartments. Redistribution of β2AR transcripts is microtubule-dependent, as microtubule depolymerization markedly reduces the number of functional receptors on the membrane. In failing hearts, both β1AR and β2AR mRNAs are redistributed toward the cell periphery, similar to what is seen in cardiomyocytes undergoing drug-induced detubulation. This suggests that t-tubule remodeling contributes to β-AR mRNA redistribution and impaired β2AR function in failing hearts. CONCLUSIONS Asymmetrical microtubule-dependent trafficking dictates differential β1AR and β2AR localization in healthy cardiomyocyte microtubules, underlying the distinctive compartmentation of the 2 β-ARs on the plasma membrane. The localization pattern is altered post-myocardial infarction, resulting from transverse tubule remodeling, leading to distorted β2AR-mediated cyclic adenosine monophosphate signaling.
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MESH Headings
- Rats
- Animals
- In Situ Hybridization, Fluorescence
- Heart Failure/metabolism
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Myocardial Infarction/metabolism
- Myocytes, Cardiac/metabolism
- Cyclic AMP/metabolism
- Receptors, Adrenergic, beta-1/metabolism
- Microtubules/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Adenosine Monophosphate/metabolism
- Adenosine Monophosphate/pharmacology
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Affiliation(s)
- Zoe Kwan
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
- Department of Chemistry (Z.K., B.P.N., A.P.I., J.B.E.), Imperial College London, United Kingdom
| | - Binoy Paulose Nadappuram
- Department of Chemistry (Z.K., B.P.N., A.P.I., J.B.E.), Imperial College London, United Kingdom
- Department of Pure and Applied Chemistry, University of Strathclyde, United Kingdom (B.P.N.)
| | - Manton M. Leung
- Sir William Dunn School of Pathology, University of Oxford, United Kingdom (M.M.L.)
| | - Sanika Mohagaonkar
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Ao Li
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Kumuthu S. Amaradasa
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Ji Chen
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Stephen Rothery
- FILM Facility, Imperial College London, United Kingdom (S.R.)
| | - Iyobel Kibreab
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Jiarong Fu
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Jose L. Sanchez-Alonso
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Catherine A. Mansfield
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | | | - Alexander Kondrashov
- Division of Cancer and Stem Cells, University of Nottingham Biodiscovery Institute, United Kingdom (A.K.)
| | - Peter T. Wright
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
- School of Life and Health Sciences, University of Roehampton, United Kingdom (P.T.W.)
| | - Pamela Swiatlowska
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Viacheslav O. Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center, Hamburg-Eppendorf, Germany (H.S., V.O.N.)
| | - Beata Wojciak-Stothard
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
| | - Aleksandar P. Ivanov
- Department of Chemistry (Z.K., B.P.N., A.P.I., J.B.E.), Imperial College London, United Kingdom
| | - Joshua B. Edel
- Department of Chemistry (Z.K., B.P.N., A.P.I., J.B.E.), Imperial College London, United Kingdom
| | - Julia Gorelik
- National Heart and Lung Institute (Z.K., S.M., A.L., K.S.A., J.C., I.K., J.F., J.L.S.-A., C.A.M., P.S., B.W.-S., P.T.W., J.G.), Imperial College London, United Kingdom
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5
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Song Q, Alvarez-Laviada A, Schrup SE, Reilly-O'Donnell B, Entcheva E, Gorelik J. Opto-SICM framework combines optogenetics with scanning ion conductance microscopy for probing cell-to-cell contacts. Commun Biol 2023; 6:1131. [PMID: 37938652 PMCID: PMC10632396 DOI: 10.1038/s42003-023-05509-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 10/26/2023] [Indexed: 11/09/2023] Open
Abstract
We present a novel framework, Opto-SICM, for studies of cellular interactions in live cells with high spatiotemporal resolution. The approach combines scanning ion conductance microscopy, SICM, and cell-type-specific optogenetic interrogation. Light-excitable cardiac fibroblasts (FB) and myofibroblasts (myoFB) were plated together with non-modified cardiomyocytes (CM) and then paced with periodic illumination. Opto-SICM reveals the extent of FB/myoFB-CM cell-cell contacts and the dynamic changes over time not visible by optical microscopy. FB-CM pairs have lower gap junctional expression of connexin-43 and higher contact dynamism compared to myoFB-CM pairs. The responsiveness of CM to pacing via FB/myoFB depends on the dynamics of the contact but not on the area. The non-responding pairs have higher net cell-cell movement at the contact. These findings are relevant to cardiac disease states, where adverse remodeling leads to abnormal electrical excitation of CM. The Opto-SICM framework can be deployed to offer new insights on cellular and subcellular interactions in various cell types, in real-time.
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Affiliation(s)
- Qianqian Song
- Imperial College London, Du Cane road, W12 0NN, London, UK
| | | | - Sarah E Schrup
- Department of Biomedical Engineering, George Washington University, Washington, DC, USA
| | | | - Emilia Entcheva
- Department of Biomedical Engineering, George Washington University, Washington, DC, USA.
| | - Julia Gorelik
- Imperial College London, Du Cane road, W12 0NN, London, UK.
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Yntema T, Koonen DPY, Kuipers F. Emerging Roles of Gut Microbial Modulation of Bile Acid Composition in the Etiology of Cardiovascular Diseases. Nutrients 2023; 15:nu15081850. [PMID: 37111068 PMCID: PMC10141989 DOI: 10.3390/nu15081850] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/04/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
Despite advances in preventive measures and treatment options, cardiovascular disease (CVD) remains the number one cause of death globally. Recent research has challenged the traditional risk factor profile and highlights the potential contribution of non-traditional factors in CVD, such as the gut microbiota and its metabolites. Disturbances in the gut microbiota have been repeatedly associated with CVD, including atherosclerosis and hypertension. Mechanistic studies support a causal role of microbiota-derived metabolites in disease development, such as short-chain fatty acids, trimethylamine-N-oxide, and bile acids, with the latter being elaborately discussed in this review. Bile acids represent a class of cholesterol derivatives that is essential for intestinal absorption of lipids and fat-soluble vitamins, plays an important role in cholesterol turnover and, as more recently discovered, acts as a group of signaling molecules that exerts hormonal functions throughout the body. Studies have shown mediating roles of bile acids in the control of lipid metabolism, immunity, and heart function. Consequently, a picture has emerged of bile acids acting as integrators and modulators of cardiometabolic pathways, highlighting their potential as therapeutic targets in CVD. In this review, we provide an overview of alterations in the gut microbiota and bile acid metabolism found in CVD patients, describe the molecular mechanisms through which bile acids may modulate CVD risk, and discuss potential bile-acid-based treatment strategies in relation to CVD.
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Affiliation(s)
- Tess Yntema
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands
| | - Debby P Y Koonen
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands
| | - Folkert Kuipers
- Department of Pediatrics, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands
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7
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Dvinskikh L, Sparks H, MacLeod KT, Dunsby C. High-speed 2D light-sheet fluorescence microscopy enables quantification of spatially varying calcium dynamics in ventricular cardiomyocytes. Front Physiol 2023; 14:1079727. [PMID: 36866170 PMCID: PMC9971815 DOI: 10.3389/fphys.2023.1079727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 01/27/2023] [Indexed: 02/16/2023] Open
Abstract
Introduction: Reduced synchrony of calcium release and t-tubule structure organization in individual cardiomyocytes has been linked to loss of contractile strength and arrhythmia. Compared to confocal scanning techniques widely used for imaging calcium dynamics in cardiac muscle cells, light-sheet fluorescence microscopy enables fast acquisition of a 2D plane in the sample with low phototoxicity. Methods: A custom light-sheet fluorescence microscope was used to achieve dual-channel 2D timelapse imaging of calcium and the sarcolemma, enabling calcium sparks and transients in left and right ventricle cardiomyocytes to be correlated with the cell microstructure. Imaging electrically stimulated dual-labelled cardiomyocytes immobilized with para-nitroblebbistatin, a non-phototoxic, low fluorescence contraction uncoupler, with sub-micron resolution at 395 fps over a 38 μm × 170 µm FOV allowed characterization of calcium spark morphology and 2D mapping of the calcium transient time-to-half-maximum across the cell. Results: Blinded analysis of the data revealed sparks with greater amplitude in left ventricle myocytes. The time for the calcium transient to reach half-maximum amplitude in the central part of the cell was found to be, on average, 2 ms shorter than at the cell ends. Sparks co-localized with t-tubules were found to have significantly longer duration, larger area and spark mass than those further away from t-tubules. Conclusion: The high spatiotemporal resolution of the microscope and automated image-analysis enabled detailed 2D mapping and quantification of calcium dynamics of n = 60 myocytes, with the findings demonstrating multi-level spatial variation of calcium dynamics across the cell, supporting the dependence of synchrony and characteristics of calcium release on the underlying t-tubule structure.
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Affiliation(s)
- Liuba Dvinskikh
- Department of Physics, Imperial College London, London, United Kingdom
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
- Department of Chemistry, Imperial College London, London, United Kingdom
| | - Hugh Sparks
- Department of Physics, Imperial College London, London, United Kingdom
| | - Kenneth T. MacLeod
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Chris Dunsby
- Department of Physics, Imperial College London, London, United Kingdom
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8
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Karsenty C, Guilbeau-Frugier C, Genet G, Seguelas MH, Alzieu P, Cazorla O, Montagner A, Blum Y, Dubroca C, Maupoint J, Tramunt B, Cauquil M, Sulpice T, Richard S, Arcucci S, Flores-Flores R, Pataluch N, Montoriol R, Sicard P, Deney A, Couffinhal T, Senard JM, Galés C. Ephrin-B1 regulates the adult diastolic function through a late postnatal maturation of cardiomyocyte surface crests. eLife 2023; 12:e80904. [PMID: 36649053 PMCID: PMC9844986 DOI: 10.7554/elife.80904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 12/30/2022] [Indexed: 01/15/2023] Open
Abstract
The rod-shaped adult cardiomyocyte (CM) harbors a unique architecture of its lateral surface with periodic crests, relying on the presence of subsarcolemmal mitochondria (SSM) with unknown role. Here, we investigated the development and functional role of CM crests during the postnatal period. We found in rodents that CM crest maturation occurs late between postnatal day 20 (P20) and P60 through both SSM biogenesis, swelling and crest-crest lateral interactions between adjacent CM, promoting tissue compaction. At the functional level, we showed that the P20-P60 period is dedicated to the improvement of relaxation. Interestingly, crest maturation specifically contributes to an atypical CM hypertrophy of its short axis, without myofibril addition, but relying on CM lateral stretching. Mechanistically, using constitutive and conditional CM-specific knock-out mice, we identified ephrin-B1, a lateral membrane stabilizer, as a molecular determinant of P20-P60 crest maturation, governing both the CM lateral stretch and the diastolic function, thus highly suggesting a link between crest maturity and diastole. Remarkably, while young adult CM-specific Efnb1 KO mice essentially exhibit an impairment of the ventricular diastole with preserved ejection fraction and exercise intolerance, they progressively switch toward systolic heart failure with 100% KO mice dying after 13 months, indicative of a critical role of CM-ephrin-B1 in the adult heart function. This study highlights the molecular determinants and the biological implication of a new late P20-P60 postnatal developmental stage of the heart in rodents during which, in part, ephrin-B1 specifically regulates the maturation of the CM surface crests and of the diastolic function.
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Affiliation(s)
- Clement Karsenty
- INSERM, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Université de ToulouseToulouseFrance
- Department of Pediatric Cardiology, Centre Hospitalier Universitaire de ToulouseToulouseFrance
| | - Celine Guilbeau-Frugier
- INSERM, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Université de ToulouseToulouseFrance
- Department of Forensic Medicine, Centre Hospitalier Universitaire de Toulouse, Université de ToulouseToulouseFrance
| | - Gaël Genet
- Department of Cell Biology, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Marie-Helene Seguelas
- INSERM, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Université de ToulouseToulouseFrance
| | - Philippe Alzieu
- Université de Bordeaux, INSERM, Biologie des maladies cardiovasculairesPessacFrance
| | - Olivier Cazorla
- Université de Montpellier, INSERM, CNRS, PhyMedExpMontpellierFrance
| | - Alexandra Montagner
- INSERM, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Université de ToulouseToulouseFrance
| | - Yuna Blum
- IGDR UMR 6290, CNRS, Université de Rennes 1RennesFrance
| | | | | | - Blandine Tramunt
- INSERM, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Université de ToulouseToulouseFrance
- Department of Diabetology, Metabolic Diseases & Nutrition, Centre Hospitalier Universitaire de ToulouseToulouseFrance
| | - Marie Cauquil
- INSERM, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Université de ToulouseToulouseFrance
| | | | - Sylvain Richard
- Université de Montpellier, INSERM, CNRS, PhyMedExpMontpellierFrance
| | - Silvia Arcucci
- INSERM, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Université de ToulouseToulouseFrance
| | - Remy Flores-Flores
- INSERM, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Université de ToulouseToulouseFrance
| | - Nicolas Pataluch
- INSERM, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Université de ToulouseToulouseFrance
| | - Romain Montoriol
- Department of Forensic Medicine, Centre Hospitalier Universitaire de Toulouse, Université de ToulouseToulouseFrance
| | - Pierre Sicard
- Université de Montpellier, INSERM, CNRS, PhyMedExpMontpellierFrance
| | - Antoine Deney
- INSERM, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Université de ToulouseToulouseFrance
| | - Thierry Couffinhal
- Université de Bordeaux, INSERM, Biologie des maladies cardiovasculairesPessacFrance
- Service des Maladies Cardiaques et Vasculaires, CHU de BordeauxBordeauxFrance
| | - Jean-Michel Senard
- INSERM, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Université de ToulouseToulouseFrance
- Department of Clinical Pharmacology, Centre Hospitalier Universitaire de ToulouseToulouseFrance
| | - Celine Galés
- INSERM, UMR 1297, Institut des Maladies Métaboliques et Cardiovasculaires, Université de ToulouseToulouseFrance
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9
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Yamada Y, Hirata K, Iida N, Kanda A, Shoji M, Yoshida T, Myachi M, Akagi R. Membrane capacitance and characteristic frequency are associated with contractile properties of skeletal muscle. Med Eng Phys 2022; 106:103832. [PMID: 35926956 DOI: 10.1016/j.medengphy.2022.103832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 06/07/2022] [Indexed: 12/13/2022]
Abstract
The cell membrane capacitance (Cm) and characteristic frequencies (fc) of tissues can be obtained using segmental bioelectrical impedance spectroscopy (S-BIS). Higher Cm and lower fc are associated with a larger surface area of skeletal muscle fibers with T-tubules in the tissues. Muscle fiber membrane is one of the major physiological factors that influence surface electromyograms (EMGs) as well as the number of recruited motor units so that the amplitude of surface EMG may be correlated with Cm and fc. The aim of the current study was to examine the association of fc or Cm in the lower leg with contractile and neuromuscular properties in the plantar flexors. We analyzed data from 59 participants (29 women) aged 21-83 years. The Cm, fc, and intracellular water (ICW) in the lower leg were obtained using S-BIS. We measured electrical-evoked torque, maximal voluntary contraction (MVC) torque, and amplitude of EMG normalized by the M wave during MVC contraction. The high Cm group had a significantly lower fc and significantly higher MVC torque, estimated maximum torque, twitch torque, and root mean square (RMS) of EMG normalized by the M wave (EMG:M) in the musculus triceps surae compared to the low Cm group (P < 0.05). Cm was positively and fc was negatively correlated with the nRMS of EMG:M in the triceps surae (P < 0.05). S-BIS recordings can be used to detect changes in skeletal muscle membrane capacitance, which may provide insights into the number of T-tubules. The muscle capacitance measured with S-BIS can be predictive of muscle force generation.
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Affiliation(s)
- Yosuke Yamada
- Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan; Department of Physical Activity Research, National Institutes of Biomedical Innovation, Health and Nutrition, Shinjuku-ku, Tokyo, Japan.
| | - Kosuke Hirata
- Faculty of Sport Sciences, Waseda University, Tokorozawa-shi, Saitama, Japan
| | - Natsuki Iida
- College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama-shi, Saitama, Japan
| | - Akihiro Kanda
- Graduate School of Engineering and Science, Shibaura Institute of Technology, Saitama-shi, Saitama, Japan; Mizuno Corporation, Suminoe-ku, Osaka, Japan
| | - Mikio Shoji
- Graduate School of Engineering and Science, Shibaura Institute of Technology, Saitama-shi, Saitama, Japan
| | - Tsukasa Yoshida
- Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan; Department of Physical Activity Research, National Institutes of Biomedical Innovation, Health and Nutrition, Shinjuku-ku, Tokyo, Japan
| | - Motohiko Myachi
- Department of Physical Activity Research, National Institutes of Biomedical Innovation, Health and Nutrition, Shinjuku-ku, Tokyo, Japan; Faculty of Sport Sciences, Waseda University, Tokorozawa-shi, Saitama, Japan
| | - Ryota Akagi
- College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama-shi, Saitama, Japan; Graduate School of Engineering and Science, Shibaura Institute of Technology, Saitama-shi, Saitama, Japan.
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10
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The insulin receptor family in the heart: new light on old insights. Biosci Rep 2022; 42:231495. [PMID: 35766350 PMCID: PMC9297685 DOI: 10.1042/bsr20221212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 06/20/2022] [Accepted: 06/29/2022] [Indexed: 11/17/2022] Open
Abstract
Insulin was discovered over 100 years ago. Whilst the first half century defined many of the physiological effects of insulin, the second emphasised the mechanisms by which it elicits these effects, implicating a vast array of G proteins and their regulators, lipid and protein kinases and counteracting phosphatases, and more. Potential growth-promoting and protective effects of insulin on the heart emerged from studies of carbohydrate metabolism in the 1960s, but the insulin receptors (and the related receptor for insulin-like growth factors 1 and 2) were not defined until the 1980s. A related third receptor, the insulin receptor-related receptor remained an orphan receptor for many years until it was identified as an alkali-sensor. The mechanisms by which these receptors and the plethora of downstream signalling molecules confer cardioprotection remain elusive. Here, we review important aspects of the effects of the three insulin receptor family members in the heart. Metabolic studies are set in the context of what is now known of insulin receptor family signalling and the role of protein kinase B (PKB or Akt), and the relationship between this and cardiomyocyte survival versus death is discussed. PKB/Akt phosphorylates numerous substrates with potential for cardioprotection in the contractile cardiomyocytes and cardiac non-myocytes. Our overall conclusion is that the effects of insulin on glucose metabolism that were initially identified remain highly pertinent in managing cardiomyocyte energetics and preservation of function. This alone provides a high level of cardioprotection in the face of pathophysiological stressors such as ischaemia and myocardial infarction.
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11
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Švecová O, Bébarová M, Šimurdová M, Šimurda J. Fraction of the T-Tubular Membrane as an Important Parameter in Cardiac Cellular Electrophysiology: A New Way of Estimation. Front Physiol 2022; 13:837239. [PMID: 35620609 PMCID: PMC9127156 DOI: 10.3389/fphys.2022.837239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 04/15/2022] [Indexed: 12/02/2022] Open
Abstract
The transverse-axial tubular system (t-tubules) plays an essential role in excitation-contraction coupling in cardiomyocytes. Its remodelling is associated with various cardiac diseases. Numerous attempts were made to analyse characteristics essential for proper understanding of the t-tubules and their impact on cardiac cell function in health and disease. The currently available methodical approaches related to the fraction of the t-tubular membrane area produce diverse data. The widely used detubulation techniques cause irreversible cell impairment, thus, distinct cell samples have to be used for estimation of t-tubular parameters in untreated and detubulated cells. Our proposed alternative method is reversible and allows repetitive estimation of the fraction of t-tubular membrane (ft) in cardiomyocytes using short-term perfusion of the measured cell with a low-conductive isotonic sucrose solution. It results in a substantial increase in the electrical resistance of t-tubular lumen, thus, electrically separating the surface and t-tubular membranes. Using the whole-cell patch-clamp measurement and the new approach in enzymatically isolated rat atrial and ventricular myocytes, a set of data was measured and evaluated. The analysis of the electrical equivalent circuit resulted in the establishment of criteria for excluding measurements in which perfusion with a low conductivity solution did not affect the entire cell surface. As expected, the final average ft in ventricular myocytes (0.337 ± 0.017) was significantly higher than that in atrial myocytes (0.144 ± 0.015). The parameter ft could be estimated repetitively in a particular cell (0.345 ± 0.021 and 0.347 ± 0.023 in ventricular myocytes during the first and second sucrose perfusion, respectively). The new method is fast, simple, and leaves the measured cell intact. It can be applied in the course of experiments for which it is useful to estimate both the surface and t-tubular capacitance/area in a particular cell.
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12
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Shati AA, Zaki MSA, Alqahtani YA, Haidara MA, Alshehri MA, Dawood AF, Eid RA. Intermittent Short-Duration Re-oxygenation Attenuates Cardiac Changes in Response to Hypoxia: Histological, Ultrastructural and Oxidant/Antioxidant Parameters. Br J Biomed Sci 2022; 79:10150. [PMID: 35996511 PMCID: PMC9302540 DOI: 10.3389/bjbs.2022.10150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 02/04/2022] [Indexed: 02/05/2023]
Abstract
Context: Intermittent short-duration re-oxygenation attenuates cardiac changes in response to hypoxia. Objective: To see if intermittent short-duration re-oxygenation may protect the heart muscle from hypoxia damage. Materials and Methods: Eighteen albino rats were used to carry out the study. Rats divided into: (normoxia); rats exposed to room air as a control, second (hypoxic) group; rats subjected to a pressure of 405 mmHg in a hypobaric chamber to simulate hypoxia at 5,000 m, and third (intermittent short-duration re-oxygenation); rats exposed to room air three times per day. Experiments were all 14 days long. Results: Hypoxia enhanced the oxidative stress biomarker malondialdehyde while lowering the antioxidant superoxide dismutase . The levels of tumour necrosis factor (TNF-α) and interleukin-6 (IL-6) in the myocardium were elevated in hypoxic hearts. The hypoxic rats’ cardiac myofibrils showed disarray of muscle fibres, vacuolation of the sarcoplasm, pyknosis of the nucleus, and expansion of intercellular gaps on histological examination. In addition, cardiomyocytes showed degenerative defects in ventricular myocardial cells on ultrastructural analysis. Myofibril thinning and degenerative mitochondrial changes affected intercalated discs with fascia adherent, desmosomes, and gap junction. Intermittent short-duration re-oxygenation improve cardiac histological, ultrastructural and oxidant/antioxidant parameters changes during hypoxia. Conclusion: Hypoxia showed a substantial impact on myocardial architecture, as well as increased oxidative stress and pro-inflammatory cytokines. Intermittent short-duration re-oxygenation significantly decreases hypoxia-induced cardiac changes.
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Affiliation(s)
- Ayed A. Shati
- Department of Child Health, College of Medicine, King Khalid University, Abha, Saudi Arabia
| | - Mohamed Samir A. Zaki
- Department of Anatomy, College of Medicine, King Khalid University, Abha, Saudi Arabia
- College of Medicine, Zagazig University, Zagazig, Egypt
- *Correspondence: Mohamed Samir A. Zaki,
| | - Youssef A. Alqahtani
- Department of Child Health, College of Medicine, King Khalid University, Abha, Saudi Arabia
| | - Mohamed A. Haidara
- Department of Physiology, Kasr al-Aini Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Mohammed A. Alshehri
- Department of Child Health, College of Medicine, King Khalid University, Abha, Saudi Arabia
| | - Amal F. Dawood
- Department of Basic Medical Sciences, College of Medicine, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Refaat A. Eid
- Department of Pathology, College of Medicine, King Khalid University, Abha, Saudi Arabia
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13
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Hoang-Trong TM, Ullah A, Lederer WJ, Jafri MS. A Stochastic Spatiotemporal Model of Rat Ventricular Myocyte Calcium Dynamics Demonstrated Necessary Features for Calcium Wave Propagation. MEMBRANES 2021; 11:989. [PMID: 34940490 PMCID: PMC8706945 DOI: 10.3390/membranes11120989] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/12/2021] [Accepted: 12/15/2021] [Indexed: 11/16/2022]
Abstract
Calcium (Ca2+) plays a central role in the excitation and contraction of cardiac myocytes. Experiments have indicated that calcium release is stochastic and regulated locally suggesting the possibility of spatially heterogeneous calcium levels in the cells. This spatial heterogeneity might be important in mediating different signaling pathways. During more than 50 years of computational cell biology, the computational models have been advanced to incorporate more ionic currents, going from deterministic models to stochastic models. While periodic increases in cytoplasmic Ca2+ concentration drive cardiac contraction, aberrant Ca2+ release can underly cardiac arrhythmia. However, the study of the spatial role of calcium ions has been limited due to the computational expense of using a three-dimensional stochastic computational model. In this paper, we introduce a three-dimensional stochastic computational model for rat ventricular myocytes at the whole-cell level that incorporate detailed calcium dynamics, with (1) non-uniform release site placement, (2) non-uniform membrane ionic currents and membrane buffers, (3) stochastic calcium-leak dynamics and (4) non-junctional or rogue ryanodine receptors. The model simulates spark-induced spark activation and spark-induced Ca2+ wave initiation and propagation that occur under conditions of calcium overload at the closed-cell condition, but not when Ca2+ levels are normal. This is considered important since the presence of Ca2+ waves contribute to the activation of arrhythmogenic currents.
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Affiliation(s)
- Tuan Minh Hoang-Trong
- School of Systems Biology, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA 22030, USA; (T.M.H.-T.); (A.U.)
| | - Aman Ullah
- School of Systems Biology, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA 22030, USA; (T.M.H.-T.); (A.U.)
| | - William Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Mohsin Saleet Jafri
- School of Systems Biology, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA 22030, USA; (T.M.H.-T.); (A.U.)
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
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14
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Lo HP, Lim YW, Xiong Z, Martel N, Ferguson C, Ariotti N, Giacomotto J, Rae J, Floetenmeyer M, Moradi SV, Gao Y, Tillu VA, Xia D, Wang H, Rahnama S, Nixon SJ, Bastiani M, Day RD, Smith KA, Palpant NJ, Johnston WA, Alexandrov K, Collins BM, Hall TE, Parton RG. Cavin4 interacts with Bin1 to promote T-tubule formation and stability in developing skeletal muscle. J Cell Biol 2021; 220:e201905065. [PMID: 34633413 PMCID: PMC8513623 DOI: 10.1083/jcb.201905065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/02/2021] [Accepted: 09/20/2021] [Indexed: 11/22/2022] Open
Abstract
The cavin proteins are essential for caveola biogenesis and function. Here, we identify a role for the muscle-specific component, Cavin4, in skeletal muscle T-tubule development by analyzing two vertebrate systems, mouse and zebrafish. In both models, Cavin4 localized to T-tubules, and loss of Cavin4 resulted in aberrant T-tubule maturation. In zebrafish, which possess duplicated cavin4 paralogs, Cavin4b was shown to directly interact with the T-tubule-associated BAR domain protein Bin1. Loss of both Cavin4a and Cavin4b caused aberrant accumulation of interconnected caveolae within the T-tubules, a fragmented T-tubule network enriched in Caveolin-3, and an impaired Ca2+ response upon mechanical stimulation. We propose a role for Cavin4 in remodeling the T-tubule membrane early in development by recycling caveolar components from the T-tubule to the sarcolemma. This generates a stable T-tubule domain lacking caveolae that is essential for T-tubule function.
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Affiliation(s)
- Harriet P. Lo
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Ye-Wheen Lim
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Zherui Xiong
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Nick Martel
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Charles Ferguson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Nicholas Ariotti
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Jean Giacomotto
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- Queensland Centre for Mental Health Research, West Moreton Hospital and Health Service and University of Queensland, Brisbane, Queensland, Australia
| | - James Rae
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Matthias Floetenmeyer
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland, Australia
| | - Shayli Varasteh Moradi
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Ya Gao
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Vikas A. Tillu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Di Xia
- Genome Innovation Hub, The University of Queensland, Brisbane, Queensland, Australia
| | - Huang Wang
- Translational Research Institute, Mater Research Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Samira Rahnama
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Susan J. Nixon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Michele Bastiani
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Ryan D. Day
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Kelly A. Smith
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Nathan J. Palpant
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Wayne A. Johnston
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Kirill Alexandrov
- CSIRO–Queensland University of Technology Synthetic Biology Alliance, ARC Centre of Excellence in Synthetic Biology, Centre for Agriculture and the Bioeconomy, School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Brett M. Collins
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Thomas E. Hall
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Robert G. Parton
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland, Australia
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15
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Setterberg IE, Le C, Frisk M, Li J, Louch WE. The Physiology and Pathophysiology of T-Tubules in the Heart. Front Physiol 2021; 12:718404. [PMID: 34566684 PMCID: PMC8458775 DOI: 10.3389/fphys.2021.718404] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/07/2021] [Indexed: 12/18/2022] Open
Abstract
In cardiomyocytes, invaginations of the sarcolemmal membrane called t-tubules are critically important for triggering contraction by excitation-contraction (EC) coupling. These structures form functional junctions with the sarcoplasmic reticulum (SR), and thereby enable close contact between L-type Ca2+ channels (LTCCs) and Ryanodine Receptors (RyRs). This arrangement in turn ensures efficient triggering of Ca2+ release, and contraction. While new data indicate that t-tubules are capable of exhibiting compensatory remodeling, they are also widely reported to be structurally and functionally compromised during disease, resulting in disrupted Ca2+ homeostasis, impaired systolic and/or diastolic function, and arrhythmogenesis. This review summarizes these findings, while highlighting an emerging appreciation of the distinct roles of t-tubules in the pathophysiology of heart failure with reduced and preserved ejection fraction (HFrEF and HFpEF). In this context, we review current understanding of the processes underlying t-tubule growth, maintenance, and degradation, underscoring the involvement of a variety of regulatory proteins, including junctophilin-2 (JPH2), amphiphysin-2 (BIN1), caveolin-3 (Cav3), and newer candidate proteins. Upstream regulation of t-tubule structure/function by cardiac workload and specifically ventricular wall stress is also discussed, alongside perspectives for novel strategies which may therapeutically target these mechanisms.
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Affiliation(s)
- Ingunn E Setterberg
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Christopher Le
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Michael Frisk
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Jia Li
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,KG Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
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16
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Piggott CA, Jin Y. Junctophilins: Key Membrane Tethers in Muscles and Neurons. Front Mol Neurosci 2021; 14:709390. [PMID: 34305529 PMCID: PMC8295595 DOI: 10.3389/fnmol.2021.709390] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 06/15/2021] [Indexed: 12/26/2022] Open
Abstract
Contacts between the endoplasmic reticulum (ER) and plasma membrane (PM) contain specialized tethering proteins that bind both ER and PM membranes. In excitable cells, ER–PM contacts play an important role in calcium signaling and transferring lipids. Junctophilins are a conserved family of ER–PM tethering proteins. They are predominantly expressed in muscles and neurons and known to simultaneously bind both ER- and PM-localized ion channels. Since their discovery two decades ago, functional studies using junctophilin-deficient animals have provided a deep understanding of their roles in muscles and neurons, including excitation-contraction coupling, store-operated calcium entry (SOCE), and afterhyperpolarization (AHP). In this review, we highlight key findings from mouse, fly, and worm that support evolutionary conservation of junctophilins.
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Affiliation(s)
- Christopher A Piggott
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, San Diego, CA, United States
| | - Yishi Jin
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, San Diego, CA, United States
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17
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Pickel S, Cruz-Garcia Y, Bandleon S, Barkovits K, Heindl C, Völker K, Abeßer M, Pfeiffer K, Schaaf A, Marcus K, Eder-Negrin P, Kuhn M, Miranda-Laferte E. The β 2-Subunit of Voltage-Gated Calcium Channels Regulates Cardiomyocyte Hypertrophy. Front Cardiovasc Med 2021; 8:704657. [PMID: 34307509 PMCID: PMC8292724 DOI: 10.3389/fcvm.2021.704657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 06/09/2021] [Indexed: 12/16/2022] Open
Abstract
L-type voltage-gated calcium channels (LTCCs) regulate crucial physiological processes in the heart. They are composed of the Cavα1 pore-forming subunit and the accessory subunits Cavβ, Cavα2δ, and Cavγ. Cavβ is a cytosolic protein that regulates channel trafficking and activity, but it also exerts other LTCC-independent functions. Cardiac hypertrophy, a relevant risk factor for the development of congestive heart failure, depends on the activation of calcium-dependent pro-hypertrophic signaling cascades. Here, by using shRNA-mediated Cavβ silencing, we demonstrate that Cavβ2 downregulation enhances α1-adrenergic receptor agonist-induced cardiomyocyte hypertrophy. We report that a pool of Cavβ2 is targeted to the nucleus in cardiomyocytes and that the expression of this nuclear fraction decreases during in vitro and in vivo induction of cardiac hypertrophy. Moreover, the overexpression of nucleus-targeted Cavβ2 in cardiomyocytes inhibits in vitro-induced hypertrophy. Quantitative proteomic analyses showed that Cavβ2 knockdown leads to changes in the expression of diverse myocyte proteins, including reduction of calpastatin, an endogenous inhibitor of the calcium-dependent protease calpain. Accordingly, Cavβ2-downregulated cardiomyocytes had a 2-fold increase in calpain activity as compared to control cells. Furthermore, inhibition of calpain activity in Cavβ2-downregulated cells abolished the enhanced α1-adrenergic receptor agonist-induced hypertrophy observed in these cells. Our findings indicate that in cardiomyocytes, a nuclear pool of Cavβ2 participates in cellular functions that are independent of LTCC activity. They also indicate that a downregulation of nuclear Cavβ2 during cardiomyocyte hypertrophy promotes the activation of calpain-dependent hypertrophic pathways.
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Affiliation(s)
- Simone Pickel
- Institute of Physiology, University of Würzburg, Würzburg, Germany
| | | | - Sandra Bandleon
- Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
| | - Katalin Barkovits
- Medizinisches Proteom-Center, Medical Faculty, Ruhr-University Bochum, Bochum, Germany.,Medical Proteome Analysis, Center for Proteindiagnostics (PRODI), Ruhr-University Bochum, Bochum, Germany
| | - Cornelia Heindl
- Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Katharina Völker
- Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Marco Abeßer
- Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Kathy Pfeiffer
- Medizinisches Proteom-Center, Medical Faculty, Ruhr-University Bochum, Bochum, Germany.,Medical Proteome Analysis, Center for Proteindiagnostics (PRODI), Ruhr-University Bochum, Bochum, Germany
| | - Alice Schaaf
- Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
| | - Katrin Marcus
- Medizinisches Proteom-Center, Medical Faculty, Ruhr-University Bochum, Bochum, Germany.,Medical Proteome Analysis, Center for Proteindiagnostics (PRODI), Ruhr-University Bochum, Bochum, Germany
| | - Petra Eder-Negrin
- Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
| | - Michaela Kuhn
- Institute of Physiology, University of Würzburg, Würzburg, Germany.,Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
| | - Erick Miranda-Laferte
- Institute of Physiology, University of Würzburg, Würzburg, Germany.,Institut für Biologische Informationsprozesse, Molekular- und Zellphysiologie (IBI-1), Forschungszentrum Jülich, Jülich, Germany
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18
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Cissom C, J Paris J, Shariat-Madar Z. Dynorphins in Development and Disease: Implications for Cardiovascular Disease. Curr Mol Med 2021; 20:259-274. [PMID: 31746302 DOI: 10.2174/1566524019666191028122559] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 10/18/2019] [Accepted: 10/18/2019] [Indexed: 12/12/2022]
Abstract
It is well-established that cardiovascular disease continues to represent a growing health problem and significant effort has been made to elucidate the underlying mechanisms. In this review, we report on past and recent high impact publications in the field of intracrine network signaling, focusing specifically on opioids and their interrelation with key modulators of the cardiovascular system and the onset of related disease. We present an overview of studies outlining the scope of cardiovascular and cerebrovascular processes that are affected by opioids, including heart function, ischemia, reperfusion, and blood flow. Specific emphasis is placed on the importance of dynorphin molecules in cerebrovascular and cardiovascular regulation. Evidence suggests that excessive or insufficient dynorphin could make an important contribution to cardiovascular physiology, yet numerous paradoxical observations frequently impede a clear understanding of the role of dynorphin. Thus, we argue that dynorphin-mediated signaling events for which an immediate regulatory effect is disputed should not be dismissed as unimportant, as they may play a role in cross-talk with other signaling networks. Finally, we consider the most recent evidence on the role of dynorphin during cardiovascular-related inflammation and on the potential value of endogenous and exogenous inhibitors of kappa-opioid receptor, a major dynorphin A receptor, to limit or prevent cardiovascular disease and its related sequelae.
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Affiliation(s)
- Cody Cissom
- William Carey College of Osteopathic Mississippi University, Medical School, Hattiesburg, Mississippi, United States
| | - Jason J Paris
- Department of Biomolecular Sciences, Division of Pharmacology, University of Mississippi, United States.,The National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, University of Mississippi, United States
| | - Zia Shariat-Madar
- Department of Biomolecular Sciences, Division of Pharmacology, University of Mississippi, United States.,The National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, University of Mississippi, United States.,Light Microscopy Core, University of Mississippi, University, Mississippi, United States
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19
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The insulin receptor family and protein kinase B (Akt) are activated in the heart by alkaline pH and α1-adrenergic receptors. Biochem J 2021; 478:2059-2079. [PMID: 34002209 PMCID: PMC8203208 DOI: 10.1042/bcj20210144] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 05/10/2021] [Accepted: 05/18/2021] [Indexed: 12/11/2022]
Abstract
Insulin and insulin-like growth factor stimulate protein synthesis and cardioprotection in the heart, acting through their receptors (INSRs, IGF1Rs) and signalling via protein kinase B (PKB, also known as Akt). Protein synthesis is increased in hearts perfused at alkaline pHo to the same extent as with insulin. Moreover, α1-adrenergic receptor (α1-AR) agonists (e.g. phenylephrine) increase protein synthesis in cardiomyocytes, activating PKB/Akt. In both cases, the mechanisms are not understood. Our aim was to determine if insulin receptor-related receptors (INSRRs, activated in kidney by alkaline pH) may account for the effects of alkaline pHo on cardiac protein synthesis, and establish if α1-ARs signal through the insulin receptor family. Alkaline pHo activated PKB/Akt signalling to the same degree as insulin in perfused adult male rat hearts. INSRRs were expressed in rat hearts and, by immunoblotting for phosphorylation (activation) of INSRRs/INSRs/IGF1Rs, we established that INSRRs, together with INSRs/IGF1Rs, are activated by alkaline pHo. The INSRR/INSR/IGF1R kinase inhibitor, linsitinib, prevented PKB/Akt activation by alkaline pHo, indicating that INSRRs/INSRs/IGF1Rs are required. Activation of PKB/Akt in cardiomyocytes by α1-AR agonists was also inhibited by linsitinib. Furthermore, linsitinib inhibited cardiomyocyte hypertrophy induced by α1-ARs in cultured cells, reduced the initial cardiac adaptation (24 h) to phenylephrine in vivo (assessed by echocardiography) and increased cardiac fibrosis over 4 days. We conclude that INSRRs are expressed in the heart and, together with INSRs/IGF1Rs, the insulin receptor family provide a potent system for promoting protein synthesis and cardioprotection. Moreover, this system is required for adaptive hypertrophy induced by α1-ARs.
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20
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Romer SH, Metzger S, Peraza K, Wright MC, Jobe DS, Song LS, Rich MM, Foy BD, Talmadge RJ, Voss AA. A mouse model of Huntington's disease shows altered ultrastructure of transverse tubules in skeletal muscle fibers. J Gen Physiol 2021; 153:211860. [PMID: 33683318 PMCID: PMC7931643 DOI: 10.1085/jgp.202012637] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 11/05/2020] [Accepted: 01/26/2021] [Indexed: 12/12/2022] Open
Abstract
Huntington’s disease (HD) is a fatal and progressive condition with severe debilitating motor defects and muscle weakness. Although classically recognized as a neurodegenerative disorder, there is increasing evidence of cell autonomous toxicity in skeletal muscle. We recently demonstrated that skeletal muscle fibers from the R6/2 model mouse of HD have a decrease in specific membrane capacitance, suggesting a loss of transverse tubule (t-tubule) membrane in R6/2 muscle. A previous report also indicated that Cav1.1 current was reduced in R6/2 skeletal muscle, suggesting defects in excitation–contraction (EC) coupling. Thus, we hypothesized that a loss and/or disruption of the skeletal muscle t-tubule system contributes to changes in EC coupling in R6/2 skeletal muscle. We used live-cell imaging with multiphoton confocal microscopy and transmission electron microscopy to assess the t-tubule architecture in late-stage R6/2 muscle and found no significant differences in the t-tubule system density, regularity, or integrity. However, electron microscopy images revealed that the cross-sectional area of t-tubules at the triad were 25% smaller in R6/2 compared with age-matched control skeletal muscle. Computer simulation revealed that the resulting decrease in the R6/2 t-tubule luminal conductance contributed to, but did not fully explain, the reduced R6/2 membrane capacitance. Analyses of bridging integrator-1 (Bin1), which plays a primary role in t-tubule formation, revealed decreased Bin1 protein levels and aberrant splicing of Bin1 mRNA in R6/2 muscle. Additionally, the distance between the t-tubule and sarcoplasmic reticulum was wider in R6/2 compared with control muscle, which was associated with a decrease in junctophilin 1 and 2 mRNA levels. Altogether, these findings can help explain dysregulated EC coupling and motor impairment in Huntington’s disease.
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Affiliation(s)
- Shannon H Romer
- Department of Biological Sciences, Wright State University, Dayton, OH.,Odyssey Systems, Environmental Health Effects Laboratory, Navy Medical Research Unit, Dayton, Wright-Patterson Air Force Base, Dayton, OH
| | - Sabrina Metzger
- Department of Neuroscience, Cell Biology, and Physiology, Wright State University, Dayton, OH
| | - Kristiana Peraza
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA
| | - Matthew C Wright
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA
| | - D Scott Jobe
- Department of Biological Sciences, Wright State University, Dayton, OH
| | - 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
| | - Mark M Rich
- Department of Neuroscience, Cell Biology, and Physiology, Wright State University, Dayton, OH
| | - Brent D Foy
- Department of Physics, Wright State University, Dayton, OH
| | - Robert J Talmadge
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA
| | - Andrew A Voss
- Department of Biological Sciences, Wright State University, Dayton, OH
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21
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Mellor NG, Pham T, Tran K, Loiselle DS, Ward M, Taberner AJ, Crossman DJ, Han J. Disruption of transverse-tubular network reduces energy efficiency in cardiac muscle contraction. Acta Physiol (Oxf) 2021; 231:e13545. [PMID: 32757472 DOI: 10.1111/apha.13545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/16/2020] [Accepted: 07/31/2020] [Indexed: 11/29/2022]
Abstract
AIM Altered organization of the transverse-tubular network is an early pathological event occurring even prior to the onset of heart failure. Such t-tubular remodelling disturbs the synchrony and signalling between membranous and intracellular ion channels, exchangers, receptors and ATPases essential in the dynamics of excitation-contraction coupling, leading to ionic abnormality and mechanical dysfunction in heart disease progression. In this study, we investigated whether a disrupted t-tubular network has a direct effect on cardiac mechano-energetics. Our aim was to understand the fundamental link between t-tubular remodelling and impaired energy metabolism, both of which are characteristics of heart failure. We thus studied healthy tissue preparations in which cellular processes are not altered by any disease event. METHODS We exploited the "formamide-detubulation" technique to acutely disrupt the t-tubular network in rat left-ventricular trabeculae. We assessed the energy utilization by cellular Ca2+ cycling and by crossbridge cycling, and quantified the change of energy efficiency following detubulation. For these measurements, trabeculae were mounted in a microcalorimeter where force and heat output were simultaneously measured. RESULTS Following structural disorganization from detubulation, muscle heat output associated with Ca2+ cycling was reduced, indicating impaired intracellular Ca2+ homeostasis. This led to reduced force production and heat output by crossbridge cycling. The reduction in force-length work was not paralleled by proportionate reduction in the heat output and, as such, energy efficiency was reduced. CONCLUSIONS These results reveal the direct energetic consequences of disrupted t-tubular network, linking the energy disturbance and the t-tubular remodelling typically observed in heart failure.
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Affiliation(s)
- Nicholas G. Mellor
- Auckland Bioengineering Institute The University of Auckland Auckland New Zealand
| | - Toan Pham
- Auckland Bioengineering Institute The University of Auckland Auckland New Zealand
| | - Kenneth Tran
- Auckland Bioengineering Institute The University of Auckland Auckland New Zealand
| | - Denis S. Loiselle
- Auckland Bioengineering Institute The University of Auckland Auckland New Zealand
- Department of Physiology The University of Auckland Auckland New Zealand
| | - Marie‐Louise Ward
- Department of Physiology The University of Auckland Auckland New Zealand
| | - Andrew J. Taberner
- Auckland Bioengineering Institute The University of Auckland Auckland New Zealand
- Department of Engineering Science The University of Auckland Auckland New Zealand
| | - David J. Crossman
- Department of Physiology The University of Auckland Auckland New Zealand
| | - June‐Chiew Han
- Auckland Bioengineering Institute The University of Auckland Auckland New Zealand
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22
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Gross P, Johnson J, Romero CM, Eaton DM, Poulet C, Sanchez-Alonso J, Lucarelli C, Ross J, Gibb AA, Garbincius JF, Lambert J, Varol E, Yang Y, Wallner M, Feldsott EA, Kubo H, Berretta RM, Yu D, Rizzo V, Elrod J, Sabri A, Gorelik J, Chen X, Houser SR. Interaction of the Joining Region in Junctophilin-2 With the L-Type Ca 2+ Channel Is Pivotal for Cardiac Dyad Assembly and Intracellular Ca 2+ Dynamics. Circ Res 2021; 128:92-114. [PMID: 33092464 PMCID: PMC7790862 DOI: 10.1161/circresaha.119.315715] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
RATIONALE Ca2+-induced Ca2+ release (CICR) in normal hearts requires close approximation of L-type calcium channels (LTCCs) within the transverse tubules (T-tubules) and RyR (ryanodine receptors) within the junctional sarcoplasmic reticulum. CICR is disrupted in cardiac hypertrophy and heart failure, which is associated with loss of T-tubules and disruption of cardiac dyads. In these conditions, LTCCs are redistributed from the T-tubules to disrupt CICR. The molecular mechanism responsible for LTCCs recruitment to and from the T-tubules is not well known. JPH (junctophilin) 2 enables close association between T-tubules and the junctional sarcoplasmic reticulum to ensure efficient CICR. JPH2 has a so-called joining region that is located near domains that interact with T-tubular plasma membrane, where LTCCs are housed. The idea that this joining region directly interacts with LTCCs and contributes to LTCC recruitment to T-tubules is unknown. OBJECTIVE To determine if the joining region in JPH2 recruits LTCCs to T-tubules through direct molecular interaction in cardiomyocytes to enable efficient CICR. METHODS AND RESULTS Modified abundance of JPH2 and redistribution of LTCC were studied in left ventricular hypertrophy in vivo and in cultured adult feline and rat ventricular myocytes. Protein-protein interaction studies showed that the joining region in JPH2 interacts with LTCC-α1C subunit and causes LTCCs distribution to the dyads, where they colocalize with RyRs. A JPH2 with induced mutations in the joining region (mutPG1JPH2) caused T-tubule remodeling and dyad loss, showing that an interaction between LTCC and JPH2 is crucial for T-tubule stabilization. mutPG1JPH2 caused asynchronous Ca2+-release with impaired excitation-contraction coupling after β-adrenergic stimulation. The disturbed Ca2+ regulation in mutPG1JPH2 overexpressing myocytes caused calcium/calmodulin-dependent kinase II activation and altered myocyte bioenergetics. CONCLUSIONS The interaction between LTCC and the joining region in JPH2 facilitates dyad assembly and maintains normal CICR in cardiomyocytes.
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MESH Headings
- Animals
- Calcium/metabolism
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Calcium Signaling
- Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism
- Cats
- Cells, Cultured
- Disease Models, Animal
- Excitation Contraction Coupling
- Humans
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/pathology
- Hypertrophy, Left Ventricular/physiopathology
- Kinetics
- Male
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mitochondria, Heart/metabolism
- Mitochondria, Heart/pathology
- Muscle Proteins/genetics
- Muscle Proteins/metabolism
- Mutation
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Organelle Biogenesis
- Protein Binding
- Protein Interaction Domains and Motifs
- Rats, Sprague-Dawley
- Ryanodine Receptor Calcium Release Channel
- Rats
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Affiliation(s)
- Polina Gross
- Lewis Katz Temple University School of Medicine, Cardiovascular Research Center, Department of Physiology, Philadelphia
| | - Jaslyn Johnson
- Lewis Katz Temple University School of Medicine, Cardiovascular Research Center, Department of Physiology, Philadelphia
| | - Carlos M. Romero
- Lewis Katz Temple University School of Medicine, Cardiovascular Research Center, Department of Physiology, Philadelphia
| | - Deborah M. Eaton
- Lewis Katz Temple University School of Medicine, Cardiovascular Research Center, Department of Physiology, Philadelphia
| | - Claire Poulet
- Imperial College London, Department of Cardiovascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, London
| | - Jose Sanchez-Alonso
- Imperial College London, Department of Cardiovascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, London
| | - Carla Lucarelli
- Imperial College London, Department of Cardiovascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, London
| | - Jean Ross
- Bioimaging Center Research, Delaware Biotechnology Institute, Newark
| | - Andrew A. Gibb
- Lewis Katz Temple University School of Medicine, Center for Translational Medicine, Department of Pharmacology, Philadelphia
| | - Joanne F. Garbincius
- Lewis Katz Temple University School of Medicine, Center for Translational Medicine, Department of Pharmacology, Philadelphia
| | - Jonathan Lambert
- Lewis Katz Temple University School of Medicine, Center for Translational Medicine, Department of Pharmacology, Philadelphia
| | - Erdem Varol
- Columbia University, Center for Theoretical Neuroscience, Department of Statistics, New York, NY
| | - Yijun Yang
- Lewis Katz Temple University School of Medicine, Cardiovascular Research Center, Department of Physiology, Philadelphia
| | - Markus Wallner
- Lewis Katz Temple University School of Medicine, Cardiovascular Research Center, Department of Physiology, Philadelphia
- Medical University of Graz, Division of Cardiology, Graz, Austria
- Center for Biomarker Research in Medicine, CBmed GmbH, Graz, Austria
| | - Eric A. Feldsott
- Lewis Katz Temple University School of Medicine, Cardiovascular Research Center, Department of Physiology, Philadelphia
| | - Hajime Kubo
- Lewis Katz Temple University School of Medicine, Cardiovascular Research Center, Department of Physiology, Philadelphia
| | - Remus M. Berretta
- Lewis Katz Temple University School of Medicine, Cardiovascular Research Center, Department of Physiology, Philadelphia
| | - Daohai Yu
- Clinical Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia
| | - Victor Rizzo
- Lewis Katz Temple University School of Medicine, Cardiovascular Research Center, Department of Physiology, Philadelphia
| | - John Elrod
- Lewis Katz Temple University School of Medicine, Center for Translational Medicine, Department of Pharmacology, Philadelphia
| | - Abdelkarim Sabri
- Lewis Katz Temple University School of Medicine, Cardiovascular Research Center, Department of Physiology, Philadelphia
| | - Julia Gorelik
- Imperial College London, Department of Cardiovascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, London
| | - Xiongwen Chen
- Lewis Katz Temple University School of Medicine, Cardiovascular Research Center, Department of Physiology, Philadelphia
| | - Steven R. Houser
- Lewis Katz Temple University School of Medicine, Cardiovascular Research Center, Department of Physiology, Philadelphia
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23
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Isolation of Adult Mouse Cardiomyocytes Using Langendorff Perfusion Apparatus. Methods Mol Biol 2021; 2319:143-152. [PMID: 34331252 PMCID: PMC9801386 DOI: 10.1007/978-1-0716-1480-8_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Heart disease is one of the leading causes of death in the United States. Isolation and culture adult cardiomyocytes are important for studying cardiomyocyte contractility, heart hypertrophy, and cardiac failure. In contrast to neonatal cardiomyocyte isolation, adult mice cardiomyocytes isolation is challenging due to firm connections among cardiomyocytes through intercalated discs. The availability of newly generated genetically modified mouse lines requires to establish protocols to isolation and culture adult mouse cardiomyocyte for in vitro studies. In this manuscript, we described a straightforward method of isolating adult mouse cardiomyocytes using Langendorff perfusion apparatus. Briefly, the hearts were harvested from adult mice and the heart was mounted to Lagendorff apparatus. After perfusion with calcium depletion and collagenase digestion, the left ventricles were minced and filtered. Lastly, the separated cardiomyocytes were treated with CaCl2. The isolated cardiac myocytes can be utilized in a broad range of experiments including screening for drugs.
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24
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Kang KW, Ok M, Lee SK. Leptin as a Key between Obesity and Cardiovascular Disease. J Obes Metab Syndr 2020; 29:248-259. [PMID: 33342767 PMCID: PMC7789022 DOI: 10.7570/jomes20120] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/03/2020] [Accepted: 12/13/2020] [Indexed: 12/14/2022] Open
Abstract
Obesity increases the risk of cardiovascular disease through various influencing factors. Leptin, which is predominantly secreted by adipose tissue, regulates satiety homeostasis and energy balance, and influences cardiovascular functions directly and indirectly. Leptin appears to play a role in heart protection in leptin-deficient and leptin-receptor-deficient rodent model experiments. Hyperleptinemia or leptin resistance in human obesity influences the vascular endothelium, cardiovascular structure and functions, inflammation, and sympathetic activity, which may lead to cardiovascular disease. Leptin is involved in many processes, including signal transduction, vascular endothelial function, and cardiac structural remodeling. However, the dual (positive and negative) regulator effect of leptin and its receptor on cardiovascular disease has not been completely understood. The protective role of leptin signaling in cardiovascular disease could be a promising target for cardiovascular disease prevention in obese patients.
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Affiliation(s)
- Ki-Woon Kang
- Division of Cardiology, Department of Internal Medicine, Eulji University School of Medicine, Daejeon, Korea
| | - Minho Ok
- Department of Cardiovascular Pharmacology, Mokpo National University, Mokpo, Korea
| | - Seong-Kyu Lee
- Division of Endocrinology, Department of Internal Medicine, Daejeon, Korea.,Department of Biochemistry-Molecular Biology, Eulji University School of Medicine, Daejeon, Korea
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25
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Jiang SJ, Wang W. Research progress on the role of CaMKII in heart disease. Am J Transl Res 2020; 12:7625-7639. [PMID: 33437349 PMCID: PMC7791482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 11/21/2020] [Indexed: 06/12/2023]
Abstract
In the heart, Ca2+ participates in electrical activity and myocardial contraction, which is closely related to the generation of action potential and excitation contraction coupling (ECC) and plays an important role in various signal cascades and regulates different physiological processes. In the Ca2+ related physiological activities, CaMKII is a key downstream regulator, involving autophosphorylation and post-translational modification, and plays an important role in the excitation contraction coupling and relaxation events of cardiomyocytes. This paper reviews the relationship between CaMKII and various substances in the pathological process of myocardial apoptosis and necrosis, myocardial hypertrophy and arrhythmia, and what roles it plays in the development of disease in complex networks. This paper also introduces the drugs targeting at CaMKII to treat heart disease.
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Affiliation(s)
- Shi-Jun Jiang
- School of Basic Medicine, Tongji Medical College, Huazhong University of Science and TechnologyWuhan 430030, Hubei, China
| | - Wei Wang
- Department of Cardiology, Affiliated Taihe Hospital of Hubei University of MedicineShiyan 442000, Hubei, China
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26
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Prisco SZ, Thenappan T, Prins KW. Treatment Targets for Right Ventricular Dysfunction in Pulmonary Arterial Hypertension. JACC Basic Transl Sci 2020; 5:1244-1260. [PMID: 33426379 PMCID: PMC7775863 DOI: 10.1016/j.jacbts.2020.07.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 01/10/2023]
Abstract
Right ventricle (RV) dysfunction is the strongest predictor of mortality in pulmonary arterial hypertension (PAH), but, at present, there are no therapies directly targeting the failing RV. Although there are shared molecular mechanisms in both RV and left ventricle (LV) dysfunction, there are important differences between the 2 ventricles that may allow for the development of RV-enhancing or RV-directed therapies. In this review, we discuss the current understandings of the dysregulated pathways that promote RV dysfunction, highlight RV-enriched or RV-specific pathways that may be of particular therapeutic value, and summarize recent and ongoing clinical trials that are investigating RV function in PAH. It is hoped that development of RV-targeted therapies will improve quality of life and enhance survival for this deadly disease.
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Key Words
- FAO, fatty acid oxidation
- IPAH, idiopathic pulmonary arterial hypertension
- LV, left ventricle/ventricular
- PAH, pulmonary arterial hypertension
- PH, pulmonary hypertension
- RAAS, renin-angiotensin-aldosterone system
- RV, right ventricle/ventricular
- RVH, right ventricular hypertrophy
- SSc-PAH, systemic sclerosis-associated pulmonary arterial hypertension
- clinical trials
- miRNA/miR, micro-ribonucleic acid
- pulmonary arterial hypertension
- right ventricle
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Affiliation(s)
- Sasha Z. Prisco
- Cardiovascular Division, Lillehei Heart Institute, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Thenappan Thenappan
- Cardiovascular Division, Lillehei Heart Institute, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Kurt W. Prins
- Cardiovascular Division, Lillehei Heart Institute, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
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27
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Park SH, Kim A, An J, Cho HS, Kang TM. Nanoscale imaging of rat atrial myocytes by scanning ion conductance microscopy reveals heterogeneity of T-tubule openings and ultrastructure of the cell membrane. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2020; 24:529-543. [PMID: 33093274 PMCID: PMC7585588 DOI: 10.4196/kjpp.2020.24.6.529] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/05/2020] [Accepted: 10/05/2020] [Indexed: 11/15/2022]
Abstract
In contrast to ventricular myocytes, the structural and functional importance of atrial transverse tubules (T-tubules) is not fully understood. Therefore, we investigated the ultrastructure of T-tubules of living rat atrial myocytes in comparison with ventricular myocytes. Nanoscale cell surface imaging by scanning ion conductance microscopy (SICM) was accompanied by confocal imaging of intracellular T-tubule network, and the effect of removal of T-tubules on atrial excitation-contraction coupling (EC-coupling) was observed. By SICM imaging, we classified atrial cell surface into 4 subtypes. About 38% of atrial myocytes had smooth cell surface with no clear T-tubule openings and intracellular T-tubules (smooth-type). In 33% of cells, we found a novel membrane nanostructure running in the direction of cell length and named it 'longitudinal fissures' (LFs-type). Interestingly, T-tubule openings were often found inside the LFs. About 17% of atrial cells resembled ventricular myocytes, but they had smaller T-tubule openings and a lower Z-groove ratio than the ventricle (ventricular-type). The remaining 12% of cells showed a mixed structure of each subtype (mixed-type). The LFs-, ventricular-, and mixed-type had an appreciable amount of reticular form of intracellular T-tubules. Formamide-induced detubulation effectively removed atrial T-tubules, which was confirmed by both confocal images and decreased cell capacitance. However, the LFs remained intact after detubulation. Detubulation reduced action potential duration and L-type Ca2+channel (LTCC) density, and prolonged relaxation time of the myocytes. Taken together, we observed heterogeneity of rat atrial T-tubules and membranous ultrastructure, and the alteration of atrial EC-coupling by disruption of T-tubules.
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Affiliation(s)
- Sun Hwa Park
- Department of Physiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Ami Kim
- Department of Physiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Jieun An
- Department of Physiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Hyun Sung Cho
- Department of Anesthesiology and Pain Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea
| | - Tong Mook Kang
- Department of Physiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
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Age-Dependent Maturation of iPSC-CMs Leads to the Enhanced Compartmentation of β 2AR-cAMP Signalling. Cells 2020; 9:cells9102275. [PMID: 33053822 PMCID: PMC7601768 DOI: 10.3390/cells9102275] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/04/2020] [Accepted: 10/05/2020] [Indexed: 12/15/2022] Open
Abstract
The ability to differentiate induced-pluripotent stem cells into cardiomyocytes (iPSC-CMs) has opened up novel avenues for potential cardiac therapies. However, iPSC-CMs exhibit a range of somewhat immature functional properties. This study explored the development of the beta-adrenergic receptor (βAR) pathway, which is crucial in regulating contraction and signifying the health and maturity of myocytes. We explored the compartmentation of β2AR-signalling and phosphodiesterases (PDEs) in caveolae, as functional nanodomains supporting the mature phenotype. Förster Resonance Energy Transfer (FRET) microscopy was used to study the cyclic adenosine monophosphate (cAMP) levels in iPSC-CMs at day 30, 60, and 90 following βAR subtype-specific stimulation. Subsequently, the PDE2, PDE3, and PDE4 activity was investigated using specific inhibitors. Cells were treated with methyl-β-cyclodextrin (MβCD) to remove cholesterol as a method of decompartmentalising β2AR. As iPSC-CMs mature with a prolonged culture time, the caveolae density is increased, leading to a reduction in the overall cytoplasmic cAMP signal stimulated through β2AR (but not β1AR). Pan-phosphodiesterase inhibition or caveolae depletion leads to an increase in the β2AR-stimulated cytoplasmic cAMP. Moreover, with time in culture, the increase in the βAR-dependent cytoplasmic cAMP becomes more sensitive to cholesterol removal. The regulation of the β2AR response by PDE2 and 4 is similarly increased with the time in culture. We conclude that both the β2AR and PDEs are restricted to the caveolae nanodomains, and thereby exhibit a tighter spatial restriction over the cAMP signal in late-stage compared to early iPSC-CMs.
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Affiliation(s)
- Michael H. Gollob
- Inherited Arrhythmia and Cardiomyopathy Program, Division of Cardiology, Department of Physiology, University of Toronto, ON, Canada
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Kubasov IV, Dobretsov MG, Bobkov DE, Panov AA. A Putative Relationship between Polymorphism of Extracellularly
Recorded Action Potentials and Organization of the T-tubular System
in Rat Ventricular and Atrial Cardiomyocytes. J EVOL BIOCHEM PHYS+ 2020. [DOI: 10.1134/s0022093020040043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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31
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Paik DT, Chandy M, Wu JC. Patient and Disease-Specific Induced Pluripotent Stem Cells for Discovery of Personalized Cardiovascular Drugs and Therapeutics. Pharmacol Rev 2020; 72:320-342. [PMID: 31871214 PMCID: PMC6934989 DOI: 10.1124/pr.116.013003] [Citation(s) in RCA: 106] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Human induced pluripotent stem cells (iPSCs) have emerged as an effective platform for regenerative therapy, disease modeling, and drug discovery. iPSCs allow for the production of limitless supply of patient-specific somatic cells that enable advancement in cardiovascular precision medicine. Over the past decade, researchers have developed protocols to differentiate iPSCs to multiple cardiovascular lineages, as well as to enhance the maturity and functionality of these cells. Despite significant advances, drug therapy and discovery for cardiovascular disease have lagged behind other fields such as oncology. We speculate that this paucity of drug discovery is due to a previous lack of efficient, reproducible, and translational model systems. Notably, existing drug discovery and testing platforms rely on animal studies and clinical trials, but investigations in animal models have inherent limitations due to interspecies differences. Moreover, clinical trials are inherently flawed by assuming that all individuals with a disease will respond identically to a therapy, ignoring the genetic and epigenomic variations that define our individuality. With ever-improving differentiation and phenotyping methods, patient-specific iPSC-derived cardiovascular cells allow unprecedented opportunities to discover new drug targets and screen compounds for cardiovascular disease. Imbued with the genetic information of an individual, iPSCs will vastly improve our ability to test drugs efficiently, as well as tailor and titrate drug therapy for each patient.
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Affiliation(s)
- David T Paik
- Stanford Cardiovascular Institute, Stanford University, Stanford, California
| | - Mark Chandy
- Stanford Cardiovascular Institute, Stanford University, Stanford, California
| | - Joseph C Wu
- Stanford Cardiovascular Institute, Stanford University, Stanford, California
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Spinozzi S, Liu C, Chen Z, Feng W, Zhang L, Ouyang K, Evans SM, Chen J. Nexilin Is Necessary for Maintaining the Transverse-Axial Tubular System in Adult Cardiomyocytes. Circ Heart Fail 2020; 13:e006935. [PMID: 32635769 PMCID: PMC7583668 DOI: 10.1161/circheartfailure.120.006935] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 03/31/2020] [Indexed: 01/28/2023]
Abstract
BACKGROUND NEXN (nexilin) is a protein of the junctional membrane complex required for development of cardiac T-tubules. Global and cardiomyocyte-specific loss of Nexn in mice leads to a rapidly progressive dilated cardiomyopathy and premature death. Therefore, little is known as to the role of NEXN in adult cardiomyocytes. Transverse-axial tubular system remodeling are well-known features in heart failure. Although NEXN is required during development for T-tubule formation, its role, if any, in mature T-tubules remains to be addressed. METHODS Nexn inducible adult cardiomyocyte-specific KO mice were generated. Comprehensive morphological and functional analyses were performed. Heart samples (n>3) were analyzed by molecular, biochemical, and electron microscopy analyses. Isolated single adult cardiomyocytes were analyzed by confocal microscopy, and myocyte shortening/re-lengthening and Ca2+ transient studies were conducted. RESULTS Inducible cardiomyocyte-specific loss of Nexn in adult mice resulted in a dilated cardiomyopathy with reduced cardiac function (13% reduction in percentage fractional shortening; P<0.05). In vivo and in vitro analyses of adult mouse heart samples revealed that NEXN was essential for optimal contraction and calcium handling and was required for maintenance of T-tubule network organization (transverse tubular component in Nexn inducible adult cardiomyocyte-specific KO mice reduced by 40% with respect to controls, P<0.05). CONCLUSIONS Results here reported reveal NEXN to be a pivotal component of adult junctional membrane complexes required for maintenance of transverse-axial tubular architecture. These results demonstrate that NEXN plays an essential role in the adult cardiomyocyte and give further understanding of pathological mechanisms responsible for cardiomyopathy in patients carrying mutations in the NEXN gene.
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MESH Headings
- Age Factors
- Animals
- Calcium/metabolism
- Cardiomyopathy, Dilated/genetics
- Cardiomyopathy, Dilated/metabolism
- Cardiomyopathy, Dilated/physiopathology
- Disease Models, Animal
- Mice
- Mice, Knockout
- Microfilament Proteins/genetics
- Microfilament Proteins/metabolism
- Microfilament Proteins/physiology
- Microtubules/metabolism
- Microtubules/physiology
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/physiology
- Ventricular Dysfunction, Left/genetics
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/physiopathology
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Affiliation(s)
- Simone Spinozzi
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Canzhao Liu
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Ze’e Chen
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Wei Feng
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Lunfeng Zhang
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Kunfu Ouyang
- Drug Discovery Center, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Sylvia M. Evans
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Ju Chen
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
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Liu Y, Zhou K, Li J, Agvanian S, Caldaruse AM, Shaw S, Hitzeman TC, Shaw RM, Hong T. In Mice Subjected to Chronic Stress, Exogenous cBIN1 Preserves Calcium-Handling Machinery and Cardiac Function. JACC Basic Transl Sci 2020; 5:561-578. [PMID: 32613144 PMCID: PMC7315191 DOI: 10.1016/j.jacbts.2020.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 03/11/2020] [Accepted: 03/11/2020] [Indexed: 12/16/2022]
Abstract
Heart failure is an important, and growing, cause of morbidity and mortality. Half of patients with heart failure have preserved ejection fraction, for whom therapeutic options are limited. Here we report that cardiac bridging integrator 1 gene therapy to maintain subcellular membrane compartments within cardiomyocytes can stabilize intracellular distribution of calcium-handling machinery, preserving diastolic function in hearts stressed by chronic beta agonist stimulation and pressure overload. This study identifies that maintenance of intracellular architecture and, in particular, membrane microdomains at t-tubules, is important in the setting of sympathetic stress. Stabilization of membrane microdomains may be a pathway for future therapeutic development.
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Key Words
- AAV9, adeno-associated virus 9
- ANOVA, analysis of variance
- AR, adrenergic receptor
- ATPase, adenosine triphosphatase
- BW, body weight
- CAMKII, Ca2+/calmodulin-dependent protein kinase
- CMV, cytomegalovirus
- Di-8-ANNEPs, 4-[2-[6-(Dioctylamino)-2-naphthalenyl]ethenyl]-1-(3-sulfopropyl)-pyridinium, inner salt
- EC, excitation contraction
- EDV, end diastolic volume
- EF, ejection fraction
- GFP, green fluorescent protein
- HF, heart failure
- HR, heart rate
- HT, heterozygote
- HW, heart weight
- ISO, isoproterenol
- LSD, least significant difference
- LTCC, voltage-dependent L-type calcium channel
- LV, left ventricular
- LW, lung weight
- PBS, phosphate-buffered saline
- PKA, protein kinase A
- PLN, phospholamban
- RWT, relative wall thickness
- RyR, ryanodine receptor
- SD, standard deviation
- SEM, standard error of the mean
- SERCA2a, sarcoplasmic reticulum calcium ATPase pump 2a
- SR, sarcoplasmic reticulum
- STORM, stochastic optical reconstruction microscopy
- TAC, transverse aortic constriction
- TEM, transmission electron microscopy
- WT, wild type
- cBIN1, cardiac bridging integrator 1
- diastolic dysfunction
- heart failure
- jSR, junctional sarcoplasmic reticulum
- pressure overload
- sympathetic overdrive
- t-tubule
- t-tubule, transverse-tubule
- vg, vector genome
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Affiliation(s)
- Yan Liu
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Kang Zhou
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Jing Li
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Sosse Agvanian
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | | | - Seiji Shaw
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Tara C Hitzeman
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
| | - Robin M Shaw
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
| | - TingTing Hong
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California.,Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, California
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Marchena M, Echebarria B. Influence of the tubular network on the characteristics of calcium transients in cardiac myocytes. PLoS One 2020; 15:e0231056. [PMID: 32302318 PMCID: PMC7164608 DOI: 10.1371/journal.pone.0231056] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 03/14/2020] [Indexed: 01/09/2023] Open
Abstract
Transverse and axial tubules (TATS) are an essential ingredient of the excitation-contraction machinery that allow the effective coupling of L-type Calcium Channels (LCC) and ryanodine receptors (RyR2). They form a regular network in ventricular cells, while their presence in atrial myocytes is variable regionally and among animal species We have studied the effect of variations in the TAT network using a bidomain computational model of an atrial myocyte with variable density of tubules. At each z-line the t-tubule length is obtained from an exponential distribution, with a given mean penetration length. This gives rise to a distribution of t-tubules in the cell that is characterized by the fractional area (F.A.) occupied by the t-tubules. To obtain consistent results, we average over different realizations of the same mean penetration length. To this, in some simulations we add the effect of a network of axial tubules. Then we study global properties of calcium signaling, as well as regional heterogeneities and local properties of sparks and RyR2 openings. In agreement with recent experiments in detubulated ventricular and atrial cells, we find that detubulation reduces the calcium transient and synchronization in release. However, it does not affect sarcoplasmic reticulum (SR) load, so the decrease in SR calcium release is due to regional differences in Ca2+ release, that is restricted to the cell periphery in detubulated cells. Despite the decrease in release, the release gain is larger in detubulated cells, due to recruitment of orphaned RyR2s, i.e, those that are not confronting a cluster of LCCs. This probably provides a safeguard mechanism, allowing physiological values to be maintained upon small changes in the t-tubule density. Finally, we do not find any relevant change in spark properties between tubulated and detubulated cells, suggesting that the differences found in experiments could be due to differential properties of the RyR2s in the membrane and in the t-tubules, not incorporated in the present model. This work will help understand the effect of detubulation, that has been shown to occur in disease conditions such as heart failure (HF) in ventricular cells, or atrial fibrillation (AF) in atrial cells.
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Affiliation(s)
- Miquel Marchena
- Departament de Física, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Blas Echebarria
- Departament de Física, Universitat Politècnica de Catalunya, Barcelona, Spain
- * E-mail:
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35
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Cohen O, Safran SA. Cardiomyocyte Calcium Ion Oscillations-Lessons From Physics. Front Physiol 2020; 11:164. [PMID: 32184736 PMCID: PMC7058634 DOI: 10.3389/fphys.2020.00164] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 02/12/2020] [Indexed: 12/22/2022] Open
Abstract
We review a theoretical, coarse-grained description for cardiomyocytes calcium dynamics that is motivated by experiments on RyR channel dynamics and provides an analogy to other spontaneously oscillating systems. We show how a minimal model, that focuses on calcium channel and pump dynamics and kinetics, results in a single, easily understood equation for spontaneous calcium oscillations (the Van-der-Pol equation). We analyze experiments on isolated RyR channels to quantify how the channel dynamics depends both on the local calcium concentration, as well as its temporal behavior (“adaptation”). Our oscillator model analytically predicts the conditions for spontaneous oscillations, their frequency and amplitude, and how each of those scale with the small number of relevant parameters related to calcium channel and pump activity. The minimal model is easily extended to include the effects of noise and external pacing (electrical or mechanical). We show how our simple oscillator predicts and explains the experimental observations of synchronization, “bursting” and reduction of apparent noise in the beating dynamics of paced cells. Thus, our analogy and theoretical approach provides robust predictions for the beating dynamics, and their biochemical and mechanical modulation.
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Affiliation(s)
- Ohad Cohen
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Samuel A Safran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
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36
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Quintana-Villamandos B, Delgado-Martos MJ, Delgado-Baeza E. Early reversal cardiac with esmolol in hypertensive rats: The role of subcellular organelle phenotype. Pharmacol Rep 2019; 71:1125-1132. [PMID: 31648130 DOI: 10.1016/j.pharep.2019.06.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 06/08/2019] [Accepted: 06/28/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND Our group has previously shown that short-term treatment (48 h) with esmolol reduces left ventricular hypertrophy (LVH) in spontaneously hypertensive rats (SHRs). However, we do not know the mechanism that explain this effect. The aim of this study was to assess the role that the subcellular organelle phenotype plays in early cardiac reverse after short-term treatment with esmolol. METHODS 14-Month-old male SHRs were randomly assigned to receive esmolol (300 μg/kg/min) (SHR-E) or vehicle (SHR). Age-matched male Wistar-Kyoto rats (WKY) served as controls. After 48 h of treatment, an ultrastructural analysis of heart tissue (left ventricle) was performed. We studied cardiomyocyte ultrastructural remodeling of subcellular organelles by electronic microcopy in all groups. RESULTS SHR group showed significant morphometric and stereological changes in mitochondria and subcellular organelles (cytoplasm and nucleus, myofibril structure, mitochondria structure, Z-Disk, intercalated disk, T-system and cystern), and also changes in the extracellular matrix (collagen) with respect to WKY group. Esmolol significantly improved the morphology and stereology mitochondrial, reduced the organelle phenotype abnormalities but no produced changes in the extracellular matrix with respect to SHR group. Interesantly, parameters of mitochondria (regularity factor, ellipsoidal form factor and density of volume), and all parameters of subcellular organelles returned to the normality in SHR-E. CONCLUSION Our results show that left ventricular hypertrophy reversal after short-term treatment with esmolol is associated with reversal of subcellular organelle phenotype.
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Affiliation(s)
- Begoña Quintana-Villamandos
- Department of Anesthesiology, Reanimation and Intensive Care, Hospital General Universitario Gregorio Marañón, Madrid, Spain; Department of Pharmacology and Toxicology, Universidad Complutense de Madrid, Spain.
| | - María Jesús Delgado-Martos
- Molecular Biology Laboratory, Department Experimental Medicine and Surgery, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; Department of Biomedicine, Universidad Francisco de Vitoria, Madrid, Spain
| | - Emilio Delgado-Baeza
- Molecular Biology Laboratory, Department Experimental Medicine and Surgery, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
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37
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Single Proteoliposome High-Content Analysis Reveals Differences in the Homo-Oligomerization of GPCRs. Biophys J 2019; 115:300-312. [PMID: 30021106 DOI: 10.1016/j.bpj.2018.05.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 05/28/2018] [Accepted: 05/31/2018] [Indexed: 11/23/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) control vital cellular signaling pathways. GPCR oligomerization is proposed to increase signaling diversity. However, many reports have arrived at disparate conclusions regarding the existence, stability, and stoichiometry of GPCR oligomers, partly because of cellular complexity and ensemble averaging of intrareconstitution heterogeneities that complicate the interpretation of oligomerization data. To overcome these limitations, we exploited fluorescence-microscopy-based high-content analysis of single proteoliposomes. This allowed multidimensional quantification of intrinsic monomer-monomer interactions of three class A GPCRs (β2-adrenergic receptor, cannabinoid receptor type 1, and opsin). Using a billion-fold less protein than conventional assays, we quantified oligomer stoichiometries, association constants, and the influence of two ligands and membrane curvature on oligomerization, revealing key similarities and differences for three GPCRs with decidedly different physiological functions. The assays introduced here will assist with the quantitative experimental observation of oligomerization for transmembrane proteins in general.
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38
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Simeonov S, Schäffer TE. Ultrafast Imaging of Cardiomyocyte Contractions by Combining Scanning Ion Conductance Microscopy with a Microelectrode Array. Anal Chem 2019; 91:9648-9655. [PMID: 31247725 DOI: 10.1021/acs.analchem.9b01092] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Beating cardiomyocytes undergo fast morphodynamics during the contraction-relaxation cycle. However, imaging these morphodynamics with a high spatial and temporal resolution is difficult, owing to a lack of suitable techniques. Here, we combine scanning ion conductance microscopy (SICM) with a microelectrode array (MEA) to image the three-dimensional (3D) topography of cardiomyocytes during a contraction-relaxation cycle with 1 μm spatial and 1 ms time resolution. We record the vertical motion of cardiomyocytes at many locations across a cell by SICM and synchronize these data using the simultaneously recorded action potential by the MEA as a time reference. This allows us to reconstruct the time-resolved 3D morphology of cardiomyocytes during a full contraction-relaxation cycle with a raw data rate of 200 μs/frame and to generate spatially resolved images of contractile parameters (maximum displacement, time delay, asymmetry factor). We use the MEA-SICM setup to visualize the effect of blebbistatin, a myosin II inhibitor, on the morphodynamics of contractions. Further, we find an upper limit of 0.02% for cell volume changes during an action potential. The results show that MEA-SICM provides an ultrafast imaging platform for investigating the functional interplay of cardiomyocyte electrophysiology and mechanics.
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Affiliation(s)
- Stefan Simeonov
- Institute of Applied Physics , University of Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
| | - Tilman E Schäffer
- Institute of Applied Physics , University of Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
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Watson SA, Perbellini F, Terracciano CM. Cardiac t-tubules: where structural plasticity meets functional adaptation. Cardiovasc Res 2019; 112:423-5. [PMID: 27659500 DOI: 10.1093/cvr/cvw198] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Samuel A Watson
- National Heart & Lung Institute, Imperial College London, Hammersmith Campus, DuCane Road, W120NN, London, UK
| | - Filippo Perbellini
- National Heart & Lung Institute, Imperial College London, Hammersmith Campus, DuCane Road, W120NN, London, UK
| | - Cesare M Terracciano
- National Heart & Lung Institute, Imperial College London, Hammersmith Campus, DuCane Road, W120NN, London, UK
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40
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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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41
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Cohen O, Safran SA. Physics of Spontaneous Calcium Oscillations in Cardiac Cells and Their Entrainment. PHYSICAL REVIEW LETTERS 2019; 122:198101. [PMID: 31144920 DOI: 10.1103/physrevlett.122.198101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 02/20/2019] [Indexed: 06/09/2023]
Abstract
Mechanical contraction in muscle cells requires Ca to allow myosin binding to actin. Beating cardiomyocytes contain internal Ca stores whose cytoplasmic concentration oscillates. Our theory explains observed single channel dynamics as well as cellular oscillations in spontaneously beating cardiomyocytes. The Ca dependence of channel activity responsible for Ca release includes positive feedback with a delayed response. We use this to predict a dynamical equation for global calcium oscillations with only a few physically relevant parameters. The theory accounts for the observed entrainment of beating to an oscillatory electric or mechanical field.
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Affiliation(s)
- Ohad Cohen
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Samuel A Safran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 76100, Israel
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Guilbeau-Frugier C, Cauquil M, Karsenty C, Lairez O, Dambrin C, Payré B, Cassard H, Josse C, Seguelas MH, Allart S, Branchereau M, Heymes C, Mandel F, Delisle MB, Pathak A, Dague E, Sénard JM, Galés C. Structural evidence for a new elaborate 3D-organization of the cardiomyocyte lateral membrane in adult mammalian cardiac tissues. Cardiovasc Res 2019; 115:1078-1091. [PMID: 30329023 DOI: 10.1093/cvr/cvy256] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 06/29/2018] [Accepted: 10/11/2018] [Indexed: 12/13/2022] Open
Abstract
AIMS This study explored the lateral crest structures of adult cardiomyocytes (CMs) within healthy and diseased cardiac tissue. METHODS AND RESULTS Using high-resolution electron and atomic force microscopy, we performed an exhaustive quantitative analysis of the three-dimensional (3D) structure of the CM lateral surface in different cardiac compartments from various mammalian species (mouse, rat, cow, and human) and determined the technical pitfalls that limit its observation. Although crests were observed in nearly all CMs from all heart compartments in all species, we showed that their heights, dictated by the subsarcolemmal mitochondria number, substantially differ between compartments from one species to another and tightly correlate with the sarcomere length. Differences in crest heights also exist between species; for example, the similar cardiac compartments in cows and humans exhibit higher crests than rodents. Unexpectedly, we found that lateral surface crests establish tight junctional contacts with crests from neighbouring CMs. Consistently, super-resolution SIM or STED-based immunofluorescence imaging of the cardiac tissue revealed intermittent claudin-5-claudin-5 interactions in trans via their extracellular part and crossing the basement membrane. Finally, we found a loss of crest structures and crest-crest contacts in diseased human CMs and in an experimental mouse model of left ventricle barometric overload. CONCLUSION Overall, these results provide the first evidence for the existence of differential CM surface crests in the cardiac tissue as well as the existence of CM-CM direct physical contacts at their lateral face through crest-crest interactions. We propose a model in which this specific 3D organization of the CM lateral membrane ensures the myofibril/myofiber alignment and the overall cardiac tissue cohesion. A potential role in the control of sarcomere relaxation and of diastolic ventricular dysfunction is also discussed. Whether the loss of CM surface crests constitutes an initial and common event leading to the CM degeneration and the setting of heart failure will need further investigation.
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MESH Headings
- Aged
- Aged, 80 and over
- Animals
- Cardiomegaly/metabolism
- Cardiomegaly/pathology
- Cattle
- Cell Membrane/metabolism
- Cell Membrane/ultrastructure
- Claudin-5/metabolism
- Cryoelectron Microscopy
- Disease Models, Animal
- Female
- Humans
- Male
- Mice, Inbred C57BL
- Microscopy, Atomic Force
- Microscopy, Electron, Scanning
- Microscopy, Electron, Transmission
- Middle Aged
- Mitochondria, Heart/ultrastructure
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/ultrastructure
- Rats, Wistar
- Sarcomeres/ultrastructure
- Species Specificity
- Tight Junctions/metabolism
- Tight Junctions/ultrastructure
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Affiliation(s)
- Céline Guilbeau-Frugier
- Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, INSERM U1048, I2MC, 1, Avenue Jean Poulhès-BP84225, Toulouse, France
- Department of Forensic Medicine, Centre Hospitalier Universitaire de Toulouse, Université de Toulouse, Toulouse, France
- Centre de Microscopie Électronique Appliquée à la Biologie, Faculté de Médecine Rangueil, Université de Toulouse, Toulouse, France
| | - Marie Cauquil
- Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, INSERM U1048, I2MC, 1, Avenue Jean Poulhès-BP84225, Toulouse, France
| | - Clément Karsenty
- Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, INSERM U1048, I2MC, 1, Avenue Jean Poulhès-BP84225, Toulouse, France
- Department of Cardiology, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
- CHU Toulouse, Pediatric and Congenital Cardiology, Children's Hospital, Université de Toulouse, Toulouse, France
| | - Olivier Lairez
- Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, INSERM U1048, I2MC, 1, Avenue Jean Poulhès-BP84225, Toulouse, France
- Department of Cardiology, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Camille Dambrin
- Department of Cardiology, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Bruno Payré
- Centre de Microscopie Électronique Appliquée à la Biologie, Faculté de Médecine Rangueil, Université de Toulouse, Toulouse, France
| | - Hervé Cassard
- UMR IHAP, Université de Toulouse, INRA, ENVT, Toulouse, France
| | - Claudie Josse
- Centre de MicroCaractérisation Raimond Castaing, UMS 3623, Toulouse, France
| | - Marie-Hélène Seguelas
- Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, INSERM U1048, I2MC, 1, Avenue Jean Poulhès-BP84225, Toulouse, France
| | - Sophie Allart
- Centre de Physiopathologie de Toulouse-Purpan, Université de Toulouse, INSERM, CNRS, Toulouse, France
| | - Maxime Branchereau
- Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, INSERM U1048, I2MC, 1, Avenue Jean Poulhès-BP84225, Toulouse, France
| | - Christophe Heymes
- Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, INSERM U1048, I2MC, 1, Avenue Jean Poulhès-BP84225, Toulouse, France
| | - Franck Mandel
- Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, INSERM U1048, I2MC, 1, Avenue Jean Poulhès-BP84225, Toulouse, France
| | - Marie-Bernadette Delisle
- Centre de Microscopie Électronique Appliquée à la Biologie, Faculté de Médecine Rangueil, Université de Toulouse, Toulouse, France
- Department of Histopathology, Centre Hospitalier Universitaire de Toulouse, Université de Toulouse, Toulouse, France
| | - Atul Pathak
- Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, INSERM U1048, I2MC, 1, Avenue Jean Poulhès-BP84225, Toulouse, France
- Department of Cardiovascular Medicine, Hypertension, Risk Factors and Heart Failure Unit, Clinique Pasteur, Toulouse, France
| | - Etienne Dague
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Jean-Michel Sénard
- Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, INSERM U1048, I2MC, 1, Avenue Jean Poulhès-BP84225, Toulouse, France
- Department of Clinical Pharmacology, Centre Hospitalier Universitaire de Toulouse, Université de Toulouse, Toulouse, France
| | - Céline Galés
- Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, INSERM U1048, I2MC, 1, Avenue Jean Poulhès-BP84225, Toulouse, France
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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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44
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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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45
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Kushnir A, Wajsberg B, Marks AR. Ryanodine receptor dysfunction in human disorders. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1687-1697. [PMID: 30040966 DOI: 10.1016/j.bbamcr.2018.07.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/13/2018] [Accepted: 07/14/2018] [Indexed: 01/07/2023]
Abstract
Regulation of intracellular calcium (Ca2+) is critical in all cell types. The ryanodine receptor (RyR), an intracellular Ca2+ release channel located on the sarco/endoplasmic reticulum (SR/ER), releases Ca2+ from intracellular stores to activate critical functions including muscle contraction and neurotransmitter release. Dysfunctional RyR-mediated Ca2+ handling has been implicated in the pathogenesis of inherited and non-inherited conditions including heart failure, cardiac arrhythmias, skeletal myopathies, diabetes, and neurodegenerative diseases. Here we have reviewed the evidence linking human disorders to RyR dysfunction and describe novel approaches to RyR-targeted therapeutics.
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Affiliation(s)
- Alexander Kushnir
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA; Department of Medicine, Division of Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Benjamin Wajsberg
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA.
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46
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Gurgul S, Buyukakilli B, Komur M, Okuyaz C, Balli E, Ozcan T. Does Levetiracetam Administration Prevent Cardiac Damage in Adulthood Rats Following Neonatal Hypoxia/Ischemia-Induced Brain Injury? ACTA ACUST UNITED AC 2018; 54:medicina54020012. [PMID: 30344243 PMCID: PMC6037241 DOI: 10.3390/medicina54020012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 12/12/2022]
Abstract
Cardiovascular abnormalities are widespread when a newborn is exposed to a hypoxic-ischemic injury in the neonatal period. Although the neuroprotective effects of levetiracetam (LEV) have been reported after hypoxia, the cardioprotective effects of LEV have not been documented. Therefore, we aimed to investigate whether levetiracetam (LEV) has a protective effect on cardiac-contractility and ultrastructure of heart muscle in rats exposed to hypoxia-ischemia (HI) during the neonatal period. A total of 49 seven-day-old rat pups were separated into four groups. For HI induction, a combination of right common carotid artery ligation with 8% oxygen in seven-day-old rat pups for 2 h was performed for saline, LEV100, and LEV200 groups. Just after hypoxia, LEV100 and LEV200 groups were administered with 100 mg/kg and 200 mg/kg of LEV, respectively. The arteries of rats in the control group were only detected; no ligation or hypoxia was performed. At the end of the 16th week after HI, cardiac mechanograms were recorded, and samples of tissue were explored by electronmicroscopy.While ventricular contractility in the control group was similar to LEV100, there were significant decreases in both saline and LEV200 groups (p < 0.05). Although ventricular contractile duration of the control and saline groups was found to be similar, durations in the LEV100 and LEV200 groups were significantly higher (p < 0.05). After HI, mitochondrial damage and ultrastructural deteriorative alterations in ventricles and atriums of the LEV-administered groups were significantly less severe than the saline group. The present study showed that neonatal HI caused long-term cardiac dysfunction and ultrastructural deteriorations in cardiac muscles. LEV administration just after HI might possess some protective effects against myocardial damage and contractility.
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Affiliation(s)
- Serkan Gurgul
- Department of Biophysics, Faculty of Medicine, Gaziantep University, TR-27310 Gaziantep, Turkey.
| | - Belgin Buyukakilli
- Department of Biophysics, Faculty of Medicine, Mersin University, TR-33343 Mersin, Turkey.
| | - Mustafa Komur
- Department of Child Health and Disease, Faculty of Medicine, Mersin University, TR-33343 Mersin, Turkey.
| | - Cetin Okuyaz
- Department of Child Health and Disease, Faculty of Medicine, Mersin University, TR-33343 Mersin, Turkey.
| | - Ebru Balli
- Department of Histology and Embryology, Faculty of Medicine, Mersin University, TR-33343 Mersin, Turkey.
| | - Tuba Ozcan
- Department of Histology and Embryology, Faculty of Medicine, K. Sütcü Imam University, TR-46040 Kahramanmaraş, Turkey.
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47
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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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48
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Kumari N, Gaur H, Bhargava A. Cardiac voltage gated calcium channels and their regulation by β-adrenergic signaling. Life Sci 2017; 194:139-149. [PMID: 29288765 DOI: 10.1016/j.lfs.2017.12.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/17/2017] [Accepted: 12/24/2017] [Indexed: 01/08/2023]
Abstract
Voltage-gated calcium channels (VGCCs) are the predominant source of calcium influx in the heart leading to calcium-induced calcium release and ultimately excitation-contraction coupling. In the heart, VGCCs are modulated by the β-adrenergic signaling. Signaling through β-adrenergic receptors (βARs) and modulation of VGCCs by β-adrenergic signaling in the heart are critical signaling and changes to these have been significantly implicated in heart failure. However, data related to calcium channel dysfunction in heart failure is divergent and contradictory ranging from reduced function to no change in the calcium current. Many recent studies have highlighted the importance of functional and spatial microdomains in the heart and that may be the key to answer several puzzling questions. In this review, we have briefly discussed the types of VGCCs found in heart tissues, their structure, and significance in the normal and pathological condition of the heart. More importantly, we have reviewed the modulation of VGCCs by βARs in normal and pathological conditions incorporating functional and structural aspects. There are different types of βARs, each having their own significance in the functioning of the heart. Finally, we emphasize the importance of location of proteins as it relates to their function and modulation by co-signaling molecules. Its implication on the studies of heart failure is speculated.
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Affiliation(s)
- Neema Kumari
- Ion Channel Biology Lab, Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana 502285, India
| | - Himanshu Gaur
- Ion Channel Biology Lab, Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana 502285, India
| | - Anamika Bhargava
- Ion Channel Biology Lab, Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana 502285, India.
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49
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Abstract
Supplemental Digital Content is available in the text. Rationale: The development of a refractory period for Ca2+ spark initiation after Ca2+ release in cardiac myocytes should inhibit further Ca2+ release during the action potential plateau. However, Ca2+ release sites that did not initially activate or which have prematurely recovered from refractoriness might release Ca2+ later during the action potential and alter the cell-wide Ca2+ transient. Objective: To investigate the possibility of late Ca2+ spark (LCS) activity in intact isolated cardiac myocytes using fast confocal line scanning with improved confocality and signal to noise. Methods and Results: We recorded Ca2+ transients from cardiac ventricular myocytes isolated from rabbit hearts. Action potentials were produced by electric stimulation, and rapid solution changes were used to modify the L-type Ca2+ current. After the upstroke of the Ca2+ transient, LCSs were detected which had increased amplitude compared with diastolic Ca2+ sparks. LCS are triggered by both L-type Ca2+ channel activity during the action potential plateau, as well as by the increase of cytosolic Ca2+ associated with the Ca2+ transient itself. Importantly, a mismatch between sarcoplasmic reticulum load and L-type Ca2+ trigger can increase the number of LCS. The likelihood of triggering an LCS also depends on recovery from refractoriness that appears after prior activation. Consequences of LCS include a reduced rate of decline of the Ca2+ transient and, if frequent, formation of microscopic propagating Ca2+ release events (Ca2+ ripples). Ca2+ ripples resemble Ca2+ waves in terms of local propagation velocity but spread for only a short distance because of limited regeneration. Conclusions: These new types of Ca2+ signaling behavior extend our understanding of Ca2+-mediated signaling. LCS may provide an arrhythmogenic substrate by slowing the Ca2+ transient decline, as well as by amplifying maintained Ca2+ current effects on intracellular Ca2+ and consequently Na+/Ca2+ exchange current.
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Affiliation(s)
- Ewan D Fowler
- From the School of Physiology, Pharmacology & Neuroscience, Faculty of Biomedical Sciences, University of Bristol, University Walk, United Kingdom
| | - Cherrie H T Kong
- From the School of Physiology, Pharmacology & Neuroscience, Faculty of Biomedical Sciences, University of Bristol, University Walk, United Kingdom
| | - Jules C Hancox
- From the School of Physiology, Pharmacology & Neuroscience, Faculty of Biomedical Sciences, University of Bristol, University Walk, United Kingdom
| | - Mark B Cannell
- From the School of Physiology, Pharmacology & Neuroscience, Faculty of Biomedical Sciences, University of Bristol, University Walk, United Kingdom.
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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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