1
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Ponnusamy T, Velusamy P, Shanmughapriya S. Mrs2-mediated mitochondrial magnesium uptake is essential for the regulation of MCU-mediated mitochondrial Ca 2+ uptake and viability. Mitochondrion 2024; 76:101877. [PMID: 38599304 DOI: 10.1016/j.mito.2024.101877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 03/07/2024] [Accepted: 04/07/2024] [Indexed: 04/12/2024]
Abstract
Mitochondrial Ca2+ uptake is essential in regulating bioenergetics, cell death, and cytosolic Ca2+ transients. Mitochondrial Calcium Uniporter (MCU) mediates the mitochondrial Ca2+ uptake. Though MCU regulation by MICUs is unequivocally established, there needs to be more knowledge of whether divalent cations regulate MCU. Here, we set out to understand the mitochondrial matrix Mg2+-dependent regulation of MCU activity. We showed that decreased matrix [Mg2+] is associated with increased MCU activity and significantly prompted mitochondrial permeability transition pore opening. Our findings support the critical role of mMg2+ in regulating MCU activity.
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Affiliation(s)
- Thiruvelselvan Ponnusamy
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Prema Velusamy
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Santhanam Shanmughapriya
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA.
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2
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Popoiu TA, Maack C, Bertero E. Mitochondrial calcium signaling and redox homeostasis in cardiac health and disease. FRONTIERS IN MOLECULAR MEDICINE 2023; 3:1235188. [PMID: 39086688 PMCID: PMC11285591 DOI: 10.3389/fmmed.2023.1235188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 08/10/2023] [Indexed: 08/02/2024]
Abstract
The energy demand of cardiomyocytes changes continuously in response to variations in cardiac workload. Cardiac excitation-contraction coupling is fueled primarily by adenosine triphosphate (ATP) production by oxidative phosphorylation in mitochondria. The rate of mitochondrial oxidative metabolism is matched to the rate of ATP consumption in the cytosol by the parallel activation of oxidative phosphorylation by calcium (Ca2+) and adenosine diphosphate (ADP). During cardiac workload transitions, Ca2+ accumulates in the mitochondrial matrix, where it stimulates the activity of the tricarboxylic acid cycle. In this review, we describe how mitochondria internalize and extrude Ca2+, the relevance of this process for ATP production and redox homeostasis in the healthy heart, and how derangements in ion handling cause mitochondrial and cardiomyocyte dysfunction in heart failure.
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Affiliation(s)
- Tudor-Alexandru Popoiu
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic Würzburg, Würzburg, Germany
- “Victor Babes” University of Medicine and Pharmacy, Timisoara, Romania
| | - Christoph Maack
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic Würzburg, Würzburg, Germany
| | - Edoardo Bertero
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic Würzburg, Würzburg, Germany
- Chair of Cardiovascular Disease, Department of Internal Medicine and Specialties, University of Genoa, Genova, Italy
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3
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Ponnusamy T, Velusamy P, Kumar A, Morris D, Zhang X, Ning G, Klinger M, Copper JE, Rajan S, Cheung JY, Natarajaseenivasan K, Mnatsakanyan N, Shanmughapriya S. Mitochondrial Magnesium is the cationic rheostat for MCU-mediated mitochondrial Ca 2+ uptake. RESEARCH SQUARE 2023:rs.3.rs-3088175. [PMID: 37502932 PMCID: PMC10371168 DOI: 10.21203/rs.3.rs-3088175/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Calcium (Ca2+) uptake by mitochondria is essential in regulating bioenergetics, cell death, and cytosolic Ca2+ transients. Mitochondrial Calcium Uniporter (MCU) mediates the mitochondrial Ca2+ uptake. MCU is a heterooligomeric complex with a pore-forming component and accessory proteins required for channel activity. Though MCU regulation by MICUs is unequivocally established, there needs to be more knowledge of whether divalent cations regulate MCU. Here we set out to understand the mitochondrial matrix Mg2+-dependent regulation of MCU activity. We showed Mrs2 as the authentic mammalian mitochondrial Mg2+ channel using the planar lipid bilayer recordings. Using a liver-specific Mrs2 KO mouse model, we showed that decreased matrix [Mg2+] is associated with increased MCU activity and matrix Ca2+ overload. The disruption of Mg2+dependent MCU regulation significantly prompted mitochondrial permeability transition pore opening-mediated cell death during tissue IR injury. Our findings support a critical role for mMg2+ in regulating MCU activity and attenuating mCa2+ overload.
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Affiliation(s)
- Thiruvelselvan Ponnusamy
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Prema Velusamy
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Amrendra Kumar
- Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Daniel Morris
- Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Xueqian Zhang
- Cardiovascular Medicine, Department of Medicine, UMass Chan Medical School, Worcester, MA 01655, USA
| | - Gang Ning
- Microscopy Core Facility, Penn State Huck Institutes of the Life Sciences, University Park, PA 16802, USA
| | - Marianne Klinger
- Department of Pathology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Jean E. Copper
- Department of Pathology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Sudarsan Rajan
- Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Joseph Y Cheung
- Department of Renal Medicine, Brigham & Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | - Nelli Mnatsakanyan
- Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Santhanam Shanmughapriya
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
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4
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Murphy E, Liu JC. Mitochondrial calcium and reactive oxygen species in cardiovascular disease. Cardiovasc Res 2023; 119:1105-1116. [PMID: 35986915 PMCID: PMC10411964 DOI: 10.1093/cvr/cvac134] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 05/26/2022] [Accepted: 06/02/2022] [Indexed: 08/11/2023] Open
Abstract
Cardiomyocytes are one of the most mitochondria-rich cell types in the body, with ∼30-40% of the cell volume being composed of mitochondria. Mitochondria are well established as the primary site of adenosine triphosphate (ATP) generation in a beating cardiomyocyte, generating up to 90% of its ATP. Mitochondria have many functions in the cell, which could contribute to susceptibility to and development of cardiovascular disease (CVD). Mitochondria are key players in cell metabolism, ATP production, reactive oxygen species (ROS) production, and cell death. Mitochondrial calcium (Ca2+) plays a critical role in many of these pathways, and thus the dynamics of mitochondrial Ca2+ are important in regulating mitochondrial processes. Alterations in these varied and in many cases interrelated functions play an important role in CVD. This review will focus on the interrelationship of mitochondrial energetics, Ca2+, and ROS and their roles in CVD. Recent insights into the regulation and dysregulation of these pathways have led to some novel therapeutic approaches.
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Affiliation(s)
- Elizabeth Murphy
- NHLBI, NIH, Bethesda, MD and Department of Integrative Biology and Physiology, University of Minnesota, 2231 6th St. SE, Minneapolis, MN 55455, USA
| | - Julia C Liu
- NHLBI, NIH, Bethesda, MD and Department of Integrative Biology and Physiology, University of Minnesota, 2231 6th St. SE, Minneapolis, MN 55455, USA
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5
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Singlár Z, Ganbat N, Szentesi P, Osgonsandag N, Szabó L, Telek A, Fodor J, Dienes B, Gönczi M, Csernoch L, Sztretye M. Genetic Manipulation of CB1 Cannabinoid Receptors Reveals a Role in Maintaining Proper Skeletal Muscle Morphology and Function in Mice. Int J Mol Sci 2022; 23:ijms232415653. [PMID: 36555292 PMCID: PMC9779148 DOI: 10.3390/ijms232415653] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/05/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022] Open
Abstract
The endocannabinoid system (ECS) refers to a widespread signaling system and its alteration is implicated in a growing number of human diseases. Cannabinoid receptors (CBRs) are highly expressed in the central nervous system and many peripheral tissues. Evidence suggests that CB1Rs are expressed in human and murine skeletal muscle mainly in the cell membrane, but a subpopulation is present also in the mitochondria. However, very little is known about the latter population. To date, the connection between the function of CB1Rs and the regulation of intracellular Ca2+ signaling has not been investigated yet. Tamoxifen-inducible skeletal muscle-specific conditional CB1 knock-down (skmCB1-KD, hereafter referred to as Cre+/-) mice were used in this study for functional and morphological analysis. After confirming CB1R down-regulation on the mRNA and protein level, we performed in vitro muscle force measurements and found that peak twitch, tetanus, and fatigue were decreased significantly in Cre+/- mice. Resting intracellular calcium concentration, voltage dependence of the calcium transients as well as the activity dependent mitochondrial calcium uptake were essentially unaltered by Cnr1 gene manipulation. Nevertheless, we found striking differences in the ultrastructural architecture of the mitochondrial network of muscle tissue from the Cre+/- mice. Our results suggest a role of CB1Rs in maintaining physiological muscle function and morphology. Targeting ECS could be a potential tool in certain diseases, including muscular dystrophies where increased endocannabinoid levels have already been described.
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Affiliation(s)
- Zoltán Singlár
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4012 Debrecen, Hungary
- Doctoral School of Molecular Medicine, University of Debrecen, 4012 Debrecen, Hungary
| | - Nyamkhuu Ganbat
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4012 Debrecen, Hungary
- Doctoral School of Molecular Medicine, University of Debrecen, 4012 Debrecen, Hungary
| | - Péter Szentesi
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4012 Debrecen, Hungary
| | - Nomin Osgonsandag
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4012 Debrecen, Hungary
| | - László Szabó
- Doctoral School of Molecular Medicine, University of Debrecen, 4012 Debrecen, Hungary
- Cell Physiology Research Group, Eötvös Loránd Research Network (ELKH), 4012 Debrecen, Hungary
| | - Andrea Telek
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4012 Debrecen, Hungary
| | - János Fodor
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4012 Debrecen, Hungary
| | - Beatrix Dienes
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4012 Debrecen, Hungary
| | - Mónika Gönczi
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4012 Debrecen, Hungary
- Cell Physiology Research Group, Eötvös Loránd Research Network (ELKH), 4012 Debrecen, Hungary
| | - László Csernoch
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4012 Debrecen, Hungary
- Cell Physiology Research Group, Eötvös Loránd Research Network (ELKH), 4012 Debrecen, Hungary
| | - Mónika Sztretye
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4012 Debrecen, Hungary
- Cell Physiology Research Group, Eötvös Loránd Research Network (ELKH), 4012 Debrecen, Hungary
- Correspondence:
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6
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Pedriali G, Ramaccini D, Bouhamida E, Wieckowski MR, Giorgi C, Tremoli E, Pinton P. Perspectives on mitochondrial relevance in cardiac ischemia/reperfusion injury. Front Cell Dev Biol 2022; 10:1082095. [PMID: 36561366 PMCID: PMC9763599 DOI: 10.3389/fcell.2022.1082095] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 11/24/2022] [Indexed: 12/12/2022] Open
Abstract
Cardiovascular disease is the most common cause of death worldwide and in particular, ischemic heart disease holds the most considerable position. Even if it has been deeply studied, myocardial ischemia-reperfusion injury (IRI) is still a side-effect of the clinical treatment for several heart diseases: ischemia process itself leads to temporary damage to heart tissue and obviously the recovery of blood flow is promptly required even if it worsens the ischemic injury. There is no doubt that mitochondria play a key role in pathogenesis of IRI: dysfunctions of these important organelles alter cell homeostasis and survival. It has been demonstrated that during IRI the system of mitochondrial quality control undergoes alterations with the disruption of the complex balance between the processes of mitochondrial fusion, fission, biogenesis and mitophagy. The fundamental role of mitochondria is carried out thanks to the finely regulated connection to other organelles such as plasma membrane, endoplasmic reticulum and nucleus, therefore impairments of these inter-organelle communications exacerbate IRI. This review pointed to enhance the importance of the mitochondrial network in the pathogenesis of IRI with the aim to focus on potential mitochondria-targeting therapies as new approach to control heart tissue damage after ischemia and reperfusion process.
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Affiliation(s)
- Gaia Pedriali
- Maria Cecilia Hospital, GVM Care and Research, Cotignola, Italy
| | | | - Esmaa Bouhamida
- Maria Cecilia Hospital, GVM Care and Research, Cotignola, Italy
| | - Mariusz R. Wieckowski
- Laboratory of Mitochondrial Biology and Metabolism, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Carlotta Giorgi
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Medical Science, Section of Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Elena Tremoli
- Maria Cecilia Hospital, GVM Care and Research, Cotignola, Italy,*Correspondence: Paolo Pinton, ; Elena Tremoli,
| | - Paolo Pinton
- Maria Cecilia Hospital, GVM Care and Research, Cotignola, Italy,Laboratory for Technologies of Advanced Therapies (LTTA), Department of Medical Science, Section of Experimental Medicine, University of Ferrara, Ferrara, Italy,*Correspondence: Paolo Pinton, ; Elena Tremoli,
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7
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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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8
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Hamilton S, Terentyeva R, Perger F, Hernández Orengo B, Martin B, Gorr MW, Belevych AE, Clements RT, Györke S, Terentyev D. MCU overexpression evokes disparate dose-dependent effects on mito-ROS and spontaneous Ca 2+ release in hypertrophic rat cardiomyocytes. Am J Physiol Heart Circ Physiol 2021; 321:H615-H632. [PMID: 34415186 PMCID: PMC8794228 DOI: 10.1152/ajpheart.00126.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 08/13/2021] [Accepted: 08/13/2021] [Indexed: 12/11/2022]
Abstract
Cardiac dysfunction in heart failure (HF) and diabetic cardiomyopathy (DCM) is associated with aberrant intracellular Ca2+ handling and impaired mitochondrial function accompanied with reduced mitochondrial calcium concentration (mito-[Ca2+]). Pharmacological or genetic facilitation of mito-Ca2+ uptake was shown to restore Ca2+ transient amplitude in DCM and HF, improving contractility. However, recent reports suggest that pharmacological enhancement of mito-Ca2+ uptake can exacerbate ryanodine receptor-mediated spontaneous sarcoplasmic reticulum (SR) Ca2+ release in ventricular myocytes (VMs) from diseased animals, increasing propensity to stress-induced ventricular tachyarrhythmia. To test whether chronic recovery of mito-[Ca2+] restores systolic Ca2+ release without adverse effects in diastole, we overexpressed mitochondrial Ca2+ uniporter (MCU) in VMs from male rat hearts with hypertrophy induced by thoracic aortic banding (TAB). Measurement of mito-[Ca2+] using genetic probe mtRCamp1h revealed that mito-[Ca2+] in TAB VMs paced at 2 Hz under β-adrenergic stimulation is lower compared with shams. Adenoviral 2.5-fold MCU overexpression in TAB VMs fully restored mito-[Ca2+]. However, it failed to improve cytosolic Ca2+ handling and reduce proarrhythmic spontaneous Ca2+ waves. Furthermore, mitochondrial-targeted genetic probes MLS-HyPer7 and OMM-HyPer revealed a significant increase in emission of reactive oxygen species (ROS) in TAB VMs with 2.5-fold MCU overexpression. Conversely, 1.5-fold MCU overexpression in TABs, that led to partial restoration of mito-[Ca2+], reduced mitochondria-derived reactive oxygen species (mito-ROS) and spontaneous Ca2+ waves. Our findings emphasize the key role of elevated mito-ROS in disease-related proarrhythmic Ca2+ mishandling. These data establish nonlinear mito-[Ca2+]/mito-ROS relationship, whereby partial restoration of mito-[Ca2+] in diseased VMs is protective, whereas further enhancement of MCU-mediated Ca2+ uptake exacerbates damaging mito-ROS emission.NEW & NOTEWORTHY Defective intracellular Ca2+ homeostasis and aberrant mitochondrial function are common features in cardiac disease. Here, we directly compared potential benefits of mito-ROS scavenging and restoration of mito-Ca2+ uptake by overexpressing MCU in ventricular myocytes from hypertrophic rat hearts. Experiments using novel mito-ROS and Ca2+ biosensors demonstrated that mito-ROS scavenging rescued both cytosolic and mito-Ca2+ homeostasis, whereas moderate and high MCU overexpression demonstrated disparate effects on mito-ROS emission, with only a moderate increase in MCU being beneficial.
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MESH Headings
- Adrenergic beta-Agonists/pharmacology
- Animals
- Arrhythmias, Cardiac/genetics
- Arrhythmias, Cardiac/metabolism
- Arrhythmias, Cardiac/pathology
- Arrhythmias, Cardiac/physiopathology
- Biosensing Techniques
- Calcium/metabolism
- Calcium Channels/genetics
- Calcium Channels/metabolism
- Calcium Signaling/drug effects
- Cells, Cultured
- Disease Models, Animal
- Heart Rate
- Hypertrophy, Left Ventricular/genetics
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/pathology
- Hypertrophy, Left Ventricular/physiopathology
- Male
- Microscopy, Confocal
- Mitochondria, Heart/drug effects
- Mitochondria, Heart/genetics
- Mitochondria, Heart/metabolism
- Mitochondria, Heart/pathology
- Myocardial Contraction
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Rats, Sprague-Dawley
- Reactive Oxygen Species/metabolism
- Up-Regulation
- Ventricular Function, Left
- Ventricular Remodeling
- Rats
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Affiliation(s)
- Shanna Hamilton
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Radmila Terentyeva
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Fruzsina Perger
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Benjamín Hernández Orengo
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Benjamin Martin
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Matthew W Gorr
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
- College of Nursing, The Ohio State University, Columbus, Ohio
| | - Andriy E Belevych
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Richard T Clements
- Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island
| | - Sandor Györke
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Dmitry Terentyev
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
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9
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Modesti L, Danese A, Angela Maria Vitto V, Ramaccini D, Aguiari G, Gafà R, Lanza G, Giorgi C, Pinton P. Mitochondrial Ca 2+ Signaling in Health, Disease and Therapy. Cells 2021; 10:cells10061317. [PMID: 34070562 PMCID: PMC8230075 DOI: 10.3390/cells10061317] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 05/21/2021] [Accepted: 05/22/2021] [Indexed: 12/12/2022] Open
Abstract
The divalent cation calcium (Ca2+) is considered one of the main second messengers inside cells and acts as the most prominent signal in a plethora of biological processes. Its homeostasis is guaranteed by an intricate and complex system of channels, pumps, and exchangers. In this context, by regulating cellular Ca2+ levels, mitochondria control both the uptake and release of Ca2+. Therefore, at the mitochondrial level, Ca2+ plays a dual role, participating in both vital physiological processes (ATP production and regulation of mitochondrial metabolism) and pathophysiological processes (cell death, cancer progression and metastasis). Hence, it is not surprising that alterations in mitochondrial Ca2+ (mCa2+) pathways or mutations in Ca2+ transporters affect the activities and functions of the entire cell. Indeed, it is widely recognized that dysregulation of mCa2+ signaling leads to various pathological scenarios, including cancer, neurological defects and cardiovascular diseases (CVDs). This review summarizes the current knowledge on the regulation of mCa2+ homeostasis, the related mechanisms and the significance of this regulation in physiology and human diseases. We also highlight strategies aimed at remedying mCa2+ dysregulation as promising therapeutical approaches.
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Affiliation(s)
- Lorenzo Modesti
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; (L.M.); (A.D.); (V.A.M.V.); (D.R.); (C.G.)
| | - Alberto Danese
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; (L.M.); (A.D.); (V.A.M.V.); (D.R.); (C.G.)
| | - Veronica Angela Maria Vitto
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; (L.M.); (A.D.); (V.A.M.V.); (D.R.); (C.G.)
| | - Daniela Ramaccini
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; (L.M.); (A.D.); (V.A.M.V.); (D.R.); (C.G.)
| | - Gianluca Aguiari
- Department of Neuroscience and Rehabilitation, University of Ferrara, 44121 Ferrara, Italy;
| | - Roberta Gafà
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (R.G.); (G.L.)
| | - Giovanni Lanza
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy; (R.G.); (G.L.)
| | - Carlotta Giorgi
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; (L.M.); (A.D.); (V.A.M.V.); (D.R.); (C.G.)
| | - Paolo Pinton
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; (L.M.); (A.D.); (V.A.M.V.); (D.R.); (C.G.)
- Correspondence: ; Tel.: +39-0532-455802
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10
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Abstract
Mitochondria are responsible for ATP production but are also known as regulators of cell death, and mitochondrial matrix Ca2+ is a key modulator of both ATP production and cell death. Although mitochondrial Ca2+ uptake and efflux have been studied for over 50 years, it is only in the past decade that the proteins responsible for mitochondrial Ca2+ uptake and efflux have been identified. The identification of the mitochondrial Ca2+ uniporter (MCU) led to an explosion of studies identifying regulators of the MCU. The levels of these regulators vary in a tissue- and disease-specific manner, providing new insight into how mitochondrial Ca2+ is regulated. This review focuses on the proteins responsible for mitochondrial transport and what we have learned from mouse studies with genetic alterations in these proteins.
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Affiliation(s)
- Elizabeth Murphy
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Charles Steenbergen
- Department of Pathology, Johns Hopkins Medicine, Baltimore, Maryland 21287, USA
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11
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Salazar-Ramírez F, Ramos-Mondragón R, García-Rivas G. Mitochondrial and Sarcoplasmic Reticulum Interconnection in Cardiac Arrhythmia. Front Cell Dev Biol 2021; 8:623381. [PMID: 33585462 PMCID: PMC7876262 DOI: 10.3389/fcell.2020.623381] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/30/2020] [Indexed: 12/31/2022] Open
Abstract
Ca2+ plays a pivotal role in mitochondrial energy production, contraction, and apoptosis. Mitochondrial Ca2+-targeted fluorescent probes have demonstrated that mitochondria Ca2+ transients are synchronized with Ca2+ fluxes occurring in the sarcoplasmic reticulum (SR). The presence of specialized proteins tethering SR to mitochondria ensures the local Ca2+ flux between these organelles. Furthermore, communication between SR and mitochondria impacts their functionality in a bidirectional manner. Mitochondrial Ca2+ uptake through the mitochondrial Ca2+ uniplex is essential for ATP production and controlled reactive oxygen species levels for proper cellular signaling. Conversely, mitochondrial ATP ensures the proper functioning of SR Ca2+-handling proteins, which ensures that mitochondria receive an adequate supply of Ca2+. Recent evidence suggests that altered SR Ca2+ proteins, such as ryanodine receptors and the sarco/endoplasmic reticulum Ca2+ ATPase pump, play an important role in maintaining proper cardiac membrane excitability, which may be initiated and potentiated when mitochondria are dysfunctional. This recognized mitochondrial role offers the opportunity to develop new therapeutic approaches aimed at preventing cardiac arrhythmias in cardiac disease.
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Affiliation(s)
- Felipe Salazar-Ramírez
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Cátedra de Cardiología y Medicina Cardiovascular, Monterrey, Mexico
| | - Roberto Ramos-Mondragón
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States.,Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Gerardo García-Rivas
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Cátedra de Cardiología y Medicina Cardiovascular, Monterrey, Mexico.,TecSalud, Centro de Investigación Biomédica, Hospital Zambrano-Hellion, San Pedro Garza García, Mexico.,TecSalud, Centro de Medicina Funcional, Hospital Zambrano-Hellion, San Pedro Garza García, Mexico
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12
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Hamilton S, Veress R, Belevych A, Terentyev D. The role of calcium homeostasis remodeling in inherited cardiac arrhythmia syndromes. Pflugers Arch 2021; 473:377-387. [PMID: 33404893 PMCID: PMC7940310 DOI: 10.1007/s00424-020-02505-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/08/2020] [Accepted: 12/10/2020] [Indexed: 02/07/2023]
Abstract
Sudden cardiac death due to malignant ventricular arrhythmias remains the major cause of mortality in the postindustrial world. Defective intracellular Ca2+ homeostasis has been well established as a key contributing factor to the enhanced propensity for arrhythmia in acquired cardiac disease, such as heart failure or diabetic cardiomyopathy. More recent advances provide a strong basis to the emerging view that hereditary cardiac arrhythmia syndromes are accompanied by maladaptive remodeling of Ca2+ homeostasis which substantially increases arrhythmic risk. This brief review will focus on functional changes in elements of Ca2+ handling machinery in cardiomyocytes that occur secondary to genetic mutations associated with catecholaminergic polymorphic ventricular tachycardia, and long QT syndrome.
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Affiliation(s)
- Shanna Hamilton
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Roland Veress
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Andriy Belevych
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Dmitry Terentyev
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, OH, USA.
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13
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Blatter LA, Kanaporis G, Martinez-Hernandez E, Oropeza-Almazan Y, Banach K. Excitation-contraction coupling and calcium release in atrial muscle. Pflugers Arch 2021; 473:317-329. [PMID: 33398498 DOI: 10.1007/s00424-020-02506-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/03/2020] [Accepted: 12/16/2020] [Indexed: 01/02/2023]
Abstract
In cardiac muscle, the process of excitation-contraction coupling (ECC) describes the chain of events that links action potential induced myocyte membrane depolarization, surface membrane ion channel activation, triggering of Ca2+ induced Ca2+ release from the sarcoplasmic reticulum (SR) Ca2+ store to activation of the contractile machinery that is ultimately responsible for the pump function of the heart. Here we review similarities and differences of structural and functional attributes of ECC between atrial and ventricular tissue. We explore a novel "fire-diffuse-uptake-fire" paradigm of atrial ECC and Ca2+ release that assigns a novel role to the SR SERCA pump and involves a concerted "tandem" activation of the ryanodine receptor Ca2+ release channel by cytosolic and luminal Ca2+. We discuss the contribution of the inositol 1,4,5-trisphosphate (IP3) receptor Ca2+ release channel as an auxiliary pathway to Ca2+ signaling, and we review IP3 receptor-induced Ca2+ release involvement in beat-to-beat ECC, nuclear Ca2+ signaling, and arrhythmogenesis. Finally, we explore the topic of electromechanical and Ca2+ alternans and its ramifications for atrial arrhythmia.
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Affiliation(s)
- L A Blatter
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA.
| | - G Kanaporis
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA
| | - E Martinez-Hernandez
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA
| | - Y Oropeza-Almazan
- Department of Physiology & Biophysics, Rush University Medical Center, 1750 W. Harrison Street, Chicago, IL, 60612, USA
| | - K Banach
- Department of Internal Medicine/Cardiology, Rush University Medical Center, Chicago, IL, 60612, USA
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14
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Srivastava SP, Kanasaki K, Goodwin JE. Loss of Mitochondrial Control Impacts Renal Health. Front Pharmacol 2020; 11:543973. [PMID: 33362536 PMCID: PMC7756079 DOI: 10.3389/fphar.2020.543973] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 11/19/2020] [Indexed: 12/13/2022] Open
Abstract
Disruption of mitochondrial biosynthesis or dynamics, or loss of control over mitochondrial regulation leads to a significant alteration in fuel preference and metabolic shifts that potentially affect the health of kidney cells. Mitochondria regulate metabolic networks which affect multiple cellular processes. Indeed, mitochondria have established themselves as therapeutic targets in several diseases. The importance of mitochondria in regulating the pathogenesis of several diseases has been recognized, however, there is limited understanding of mitochondrial biology in the kidney. This review provides an overview of mitochondrial dysfunction in kidney diseases. We describe the importance of mitochondria and mitochondrial sirtuins in the regulation of renal metabolic shifts in diverse cells types, and review this loss of control leads to increased cell-to-cell transdifferentiation processes and myofibroblast-metabolic shifts, which affect the pathophysiology of several kidney diseases. In addition, we examine mitochondrial-targeted therapeutic agents that offer potential leads in combating kidney diseases.
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Affiliation(s)
- Swayam Prakash Srivastava
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT, United States
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, United States
| | - Keizo Kanasaki
- Internal Medicine 1, Shimane University Faculty of Medicine, Izumo, Japan
| | - Julie E. Goodwin
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT, United States
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, United States
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15
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The Physiological and Pathological Roles of Mitochondrial Calcium Uptake in Heart. Int J Mol Sci 2020; 21:ijms21207689. [PMID: 33080805 PMCID: PMC7589179 DOI: 10.3390/ijms21207689] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/12/2020] [Accepted: 10/16/2020] [Indexed: 12/17/2022] Open
Abstract
Calcium ion (Ca2+) plays a critical role in the cardiac mitochondria function. Ca2+ entering the mitochondria is necessary for ATP production and the contractile activity of cardiomyocytes. However, excessive Ca2+ in the mitochondria results in mitochondrial dysfunction and cell death. Mitochondria maintain Ca2+ homeostasis in normal cardiomyocytes through a comprehensive regulatory mechanism by controlling the uptake and release of Ca2+ in response to the cellular demand. Understanding the mechanism of modulating mitochondrial Ca2+ homeostasis in the cardiomyocyte could bring new insights into the pathogenesis of cardiac disease and help developing the strategy to prevent the heart from damage at an early stage. In this review, we summarized the latest findings in the studies on the cardiac mitochondrial Ca2+ homeostasis, focusing on the regulation of mitochondrial calcium uptake, which acts as a double-edged sword in the cardiac function. Specifically, we discussed the dual roles of mitochondrial Ca2+ in mitochondrial activity and the impact on cardiac function, the molecular basis and regulatory mechanisms, and the potential future research interest.
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16
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Oropeza-Almazán Y, Blatter LA. Mitochondrial calcium uniporter complex activation protects against calcium alternans in atrial myocytes. Am J Physiol Heart Circ Physiol 2020; 319:H873-H881. [PMID: 32857593 DOI: 10.1152/ajpheart.00375.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cardiac alternans, defined as beat-to-beat alternations in action potential duration, cytosolic Ca transient (CaT) amplitude, and cardiac contraction is associated with atrial fibrillation (AF) and sudden cardiac death. At the cellular level, cardiac alternans is linked to abnormal intracellular calcium handling during excitation-contraction coupling. We investigated how pharmacological activation or inhibition of cytosolic Ca sequestration via mitochondrial Ca uptake and mitochondrial Ca retention affects the occurrence of pacing-induced CaT alternans in isolated rabbit atrial myocytes. Cytosolic CaTs were recorded using Fluo-4 fluorescence microscopy. Alternans was quantified as the alternans ratio (AR = 1 - CaTsmall/CaTlarge, where CaTsmall and CaTlarge are the amplitudes of the small and large CaTs of a pair of alternating CaTs). Inhibition of mitochondrial Ca sequestration via mitochondrial Ca uniporter complex (MCUC) with Ru360 enhanced the severity of CaT alternans (AR increase) and lowered the pacing frequency threshold for alternans. In contrast, stimulation of MCUC mediated mitochondrial Ca uptake with spermine-rescued alternans (AR decrease) and increased the alternans pacing threshold. Direct measurement of mitochondrial [Ca] in membrane permeabilized myocytes with Fluo-4 loaded mitochondria revealed that spermine enhanced and accelerated mitochondrial Ca uptake. Stimulation of mitochondrial Ca retention by preventing mitochondrial Ca efflux through the mitochondrial permeability transition pore with cyclosporin A also protected from alternans and increased the alternans pacing threshold. Pharmacological manipulation of MCUC activity did not affect sarcoplasmic reticulum Ca load. Our results suggest that activation of Ca sequestration by mitochondria protects from CaT alternans and could be a potential therapeutic target for cardiac alternans and AF prevention.NEW & NOTEWORTHY This study provides conclusive evidence that mitochondrial Ca uptake and retention protects from Ca alternans, whereas uptake inhibition enhances Ca alternans. The data suggest pharmacological mitochondrial Ca cycling modulation as a potential therapeutic strategy for alternans-related cardiac arrhythmia prevention.
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Affiliation(s)
| | - Lothar A Blatter
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, Illinois
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17
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Kulkarni K, Merchant FM, Kassab MB, Sana F, Moazzami K, Sayadi O, Singh JP, Heist EK, Armoundas AA. Cardiac Alternans: Mechanisms and Clinical Utility in Arrhythmia Prevention. J Am Heart Assoc 2019; 8:e013750. [PMID: 31617437 PMCID: PMC6898836 DOI: 10.1161/jaha.119.013750] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Kanchan Kulkarni
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | | | - Mohamad B. Kassab
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Furrukh Sana
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Kasra Moazzami
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Omid Sayadi
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
| | - Jagmeet P. Singh
- Cardiology DivisionCardiac Arrhythmia ServiceMassachusetts General HospitalBostonMA
| | - E. Kevin Heist
- Cardiology DivisionCardiac Arrhythmia ServiceMassachusetts General HospitalBostonMA
| | - Antonis A. Armoundas
- Cardiovascular Research CenterMassachusetts General HospitalBostonMA
- Institute for Medical Engineering and ScienceMassachusetts Institute of TechnologyCambridgeMA
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18
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Abstract
In heart failure, alterations of Na+ and Ca2+ handling, energetic deficit, and oxidative stress in cardiac myocytes are important pathophysiological hallmarks. Mitochondria are central to these processes because they are the main source for ATP, but also reactive oxygen species (ROS), and their function is critically controlled by Ca2+ During physiological variations of workload, mitochondrial Ca2+ uptake is required to match energy supply to demand but also to keep the antioxidative capacity in a reduced state to prevent excessive emission of ROS. Mitochondria take up Ca2+ via the mitochondrial Ca2+ uniporter, which exists in a multiprotein complex whose molecular components were identified only recently. In heart failure, deterioration of cytosolic Ca2+ and Na+ handling hampers mitochondrial Ca2+ uptake and the ensuing Krebs cycle-induced regeneration of the reduced forms of NADH (nicotinamide adenine dinucleotide) and NADPH (nicotinamide adenine dinucleotide phosphate), giving rise to energetic deficit and oxidative stress. ROS emission from mitochondria can trigger further ROS release from neighboring mitochondria termed ROS-induced ROS release, and cross talk between different ROS sources provides a spatially confined cellular network of redox signaling. Although low levels of ROS may serve physiological roles, higher levels interfere with excitation-contraction coupling, induce maladaptive cardiac remodeling through redox-sensitive kinases, and cell death through mitochondrial permeability transition. Targeting the dysregulated interplay between excitation-contraction coupling and mitochondrial energetics may ameliorate the progression of heart failure.
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Affiliation(s)
- Edoardo Bertero
- From the Comprehensive Heart Failure Center, University Clinic Würzburg, Germany
| | - Christoph Maack
- From the Comprehensive Heart Failure Center, University Clinic Würzburg, Germany.
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19
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Hamilton S, Terentyev D. Altered Intracellular Calcium Homeostasis and Arrhythmogenesis in the Aged Heart. Int J Mol Sci 2019; 20:ijms20102386. [PMID: 31091723 PMCID: PMC6566636 DOI: 10.3390/ijms20102386] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 04/29/2019] [Accepted: 05/08/2019] [Indexed: 12/17/2022] Open
Abstract
Aging of the heart is associated with a blunted response to sympathetic stimulation, reduced contractility, and increased propensity for arrhythmias, with the risk of sudden cardiac death significantly increased in the elderly population. The altered cardiac structural and functional phenotype, as well as age-associated prevalent comorbidities including hypertension and atherosclerosis, predispose the heart to atrial fibrillation, heart failure, and ventricular tachyarrhythmias. At the cellular level, perturbations in mitochondrial function, excitation-contraction coupling, and calcium homeostasis contribute to this electrical and contractile dysfunction. Major determinants of cardiac contractility are the intracellular release of Ca2+ from the sarcoplasmic reticulum by the ryanodine receptors (RyR2), and the following sequestration of Ca2+ by the sarco/endoplasmic Ca2+-ATPase (SERCa2a). Activity of RyR2 and SERCa2a in myocytes is not only dependent on expression levels and interacting accessory proteins, but on fine-tuned regulation via post-translational modifications. In this paper, we review how aberrant changes in intracellular Ca2+ cycling via these proteins contributes to arrhythmogenesis in the aged heart.
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Affiliation(s)
- Shanna Hamilton
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210, USA.
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA.
| | - Dmitry Terentyev
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210, USA.
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA.
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20
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Hamilton S, Terentyeva R, Kim TY, Bronk P, Clements RT, O-Uchi J, Csordás G, Choi BR, Terentyev D. Pharmacological Modulation of Mitochondrial Ca 2+ Content Regulates Sarcoplasmic Reticulum Ca 2+ Release via Oxidation of the Ryanodine Receptor by Mitochondria-Derived Reactive Oxygen Species. Front Physiol 2018; 9:1831. [PMID: 30622478 PMCID: PMC6308295 DOI: 10.3389/fphys.2018.01831] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/06/2018] [Indexed: 01/09/2023] Open
Abstract
In a physiological setting, mitochondria increase oxidative phosphorylation during periods of stress to meet increased metabolic demand. This in part is mediated via enhanced mitochondrial Ca2+ uptake, an important regulator of cellular ATP homeostasis. In a pathophysiological setting pharmacological modulation of mitochondrial Ca2+ uptake or retention has been suggested as a therapeutic strategy to improve metabolic homeostasis or attenuate Ca2+-dependent arrhythmias in cardiac disease states. To explore the consequences of mitochondrial Ca2+ accumulation, we tested the effects of kaempferol, an activator of mitochondrial Ca2+ uniporter (MCU), CGP-37157, an inhibitor of mitochondrial Na+/Ca2+ exchanger, and MCU inhibitor Ru360 in rat ventricular myocytes (VMs) from control rats and rats with hypertrophy induced by thoracic aortic banding (TAB). In periodically paced VMs under β-adrenergic stimulation, treatment with kaempferol (10 μmol/L) or CGP-37157 (1 μmol/L) enhanced mitochondrial Ca2+ accumulation monitored by mitochondrial-targeted Ca2+ biosensor mtRCamp1h. Experiments with mitochondrial membrane potential-sensitive dye TMRM revealed this was accompanied by depolarization of the mitochondrial matrix. Using redox-sensitive OMM-HyPer and ERroGFP_iE biosensors, we found treatment with kaempferol or CGP-37157 increased the levels of reactive oxygen species (ROS) in mitochondria and the sarcoplasmic reticulum (SR), respectively. Confocal Ca2+ imaging showed that accelerated Ca2+ accumulation reduced Ca2+ transient amplitude and promoted generation of spontaneous Ca2+ waves in VMs paced under ISO, suggestive of abnormally high activity of the SR Ca2+ release channel ryanodine receptor (RyR). Western blot analyses showed increased RyR oxidation after treatment with kaempferol or CGP-37157 vs. controls. Furthermore, in freshly isolated TAB VMs, confocal Ca2+ imaging demonstrated that enhancement of mitochondrial Ca2+ accumulation further perturbed global Ca2+ handling, increasing the number of cells exhibiting spontaneous Ca2+ waves, shortening RyR refractoriness and decreasing SR Ca2+ content. In ex vivo optically mapped TAB hearts, kaempferol exacerbated proarrhythmic phenotype. On the contrary, incubation of cells with MCU inhibitor Ru360 (2 μmol/L, 30 min) normalized RyR oxidation state, improved intracellular Ca2+ homeostasis and reduced triggered activity in ex vivo TAB hearts. These findings suggest facilitation of mitochondrial Ca2+ uptake in cardiac disease can exacerbate proarrhythmic disturbances in Ca2+ homeostasis via ROS and enhanced activity of oxidized RyRs, while strategies to reduce mitochondrial Ca2+ accumulation can be protective.
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Affiliation(s)
- Shanna Hamilton
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, United States
| | - Radmila Terentyeva
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, United States
| | - Tae Yun Kim
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, United States
| | - Peter Bronk
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, United States
| | - Richard T. Clements
- Department of Surgery, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, United States
- Vascular Research Laboratory, Providence Veterans Affairs Medical Center, Providence, RI, United States
| | - Jin O-Uchi
- Lillehei Heart Institute University of Minnesota, Cancer and Cardiovascular Research Building, Minneapolis, MN, United States
| | - György Csordás
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Bum-Rak Choi
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, United States
| | - Dmitry Terentyev
- Department of Medicine, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Cardiovascular Research Center, Providence, RI, United States
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21
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Giorgi C, Marchi S, Pinton P. The machineries, regulation and cellular functions of mitochondrial calcium. Nat Rev Mol Cell Biol 2018; 19:713-730. [PMID: 30143745 DOI: 10.1038/s41580-018-0052-8] [Citation(s) in RCA: 481] [Impact Index Per Article: 80.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Calcium ions (Ca2+) are some of the most versatile signalling molecules, and they have many physiological functions, prominently including muscle contraction, neuronal excitability, cell migration and cell growth. By sequestering and releasing Ca2+, mitochondria serve as important regulators of cellular Ca2+. Mitochondrial Ca2+ also has other important functions, such as regulation of mitochondrial metabolism, ATP production and cell death. In recent years, identification of the molecular machinery regulating mitochondrial Ca2+ accumulation and efflux has expanded the number of (patho)physiological conditions that rely on mitochondrial Ca2+ homeostasis. Thus, expanding the understanding of the mechanisms of mitochondrial Ca2+ regulation and function in different cell types is an important task in biomedical research, which offers the possibility of targeting mitochondrial Ca2+ machinery for the treatment of several disorders.
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Affiliation(s)
- Carlotta Giorgi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Saverio Marchi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy. .,Maria Cecilia Hospital, GVM Care and Research, Cotignola, Ravenna, Italy.
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22
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Xie A, Song Z, Liu H, Zhou A, Shi G, Wang Q, Gu L, Liu M, Xie LH, Qu Z, Dudley SC. Mitochondrial Ca 2+ Influx Contributes to Arrhythmic Risk in Nonischemic Cardiomyopathy. J Am Heart Assoc 2018; 7:e007805. [PMID: 29627768 PMCID: PMC6015427 DOI: 10.1161/jaha.117.007805] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 03/07/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND Heart failure (HF) is associated with increased arrhythmia risk and triggered activity. Abnormal Ca2+ handling is thought to underlie triggered activity, and mitochondria participate in Ca2+ homeostasis. METHODS AND RESULTS A model of nonischemic HF was induced in C57BL/6 mice by hypertension. Computer simulations were performed using a mouse ventricular myocyte model of HF. Isoproterenol-induced premature ventricular contractions and ventricular fibrillation were more prevalent in nonischemic HF mice than sham controls. Isolated myopathic myocytes showed decreased cytoplasmic Ca2+ transients, increased mitochondrial Ca2+ transients, and increased action potential duration at 90% repolarization. The alteration of action potential duration at 90% repolarization was consistent with in vivo corrected QT prolongation and could be explained by augmented L-type Ca2+ currents, increased Na+-Ca2+ exchange currents, and decreased total K+ currents. Of myopathic ventricular myocytes, 66% showed early afterdepolarizations (EADs) compared with 17% of sham myocytes (P<0.05). Intracellular application of 1 μmol/L Ru360, a mitochondrial Ca2+ uniporter-specific antagonist, could reduce mitochondrial Ca2+ transients, decrease action potential duration at 90% repolarization, and ameliorate EADs. Furthermore, genetic knockdown of mitochondrial Ca2+ uniporters inhibited mitochondrial Ca2+ uptake, reduced Na+-Ca2+ exchange currents, decreased action potential duration at 90% repolarization, suppressed EADs, and reduced ventricular fibrillation in nonischemic HF mice. Computer simulations showed that EADs promoted by HF remodeling could be abolished by blocking either the mitochondrial Ca2+ uniporter or the L-type Ca2+ current, consistent with the experimental observations. CONCLUSIONS Mitochondrial Ca2+ handling plays an important role in EADs seen with nonischemic cardiomyopathy and may represent a therapeutic target to reduce arrhythmic risk in this condition.
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Affiliation(s)
- An Xie
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Zhen Song
- Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA
| | - Hong Liu
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Anyu Zhou
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Guangbin Shi
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Qiongying Wang
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Lianzhi Gu
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Man Liu
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
| | - Lai-Hua Xie
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School Rutgers, The State University of New Jersey, Newark, NJ
| | - Zhilin Qu
- Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA
| | - Samuel C Dudley
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN
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23
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Parks RJ, Murphy E, Liu JC. Mitochondrial Permeability Transition Pore and Calcium Handling. Methods Mol Biol 2018; 1782:187-196. [PMID: 29851001 DOI: 10.1007/978-1-4939-7831-1_11] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The opening of a large conductance channel in the inner mitochondrial membrane, known as the mitochondrial permeability transition pore (PTP), has been shown to be a primary mediator of cell death in the heart subjected to ischemia-reperfusion injury. Inhibitors of the PTP have been shown to reduce cardiac ischemia-reperfusion injury in many animal models. Furthermore, most cardioprotective strategies appear to reduce ischemic cell death either by reducing the triggers for the opening of the PTP, such as reducing calcium overload or reactive oxygen species, or by inhibiting PTP modulators. This chapter will focus on key issues in the study of the PTP and provide some methods for measuring PTP opening in isolated mitochondria.
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Affiliation(s)
- Randi J Parks
- Systems Biology Center, NHLBI, NIH, Bethesda, MD, 20892, USA
| | | | - Julia C Liu
- Systems Biology Center, NHLBI, NIH, Bethesda, MD, 20892, USA.
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24
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Schweitzer MK, Wilting F, Sedej S, Dreizehnter L, Dupper NJ, Tian Q, Moretti A, My I, Kwon O, Priori SG, Laugwitz KL, Storch U, Lipp P, Breit A, Mederos y Schnitzler M, Gudermann T, Schredelseker J. Suppression of Arrhythmia by Enhancing Mitochondrial Ca 2+ Uptake in Catecholaminergic Ventricular Tachycardia Models. JACC Basic Transl Sci 2017; 2:737-747. [PMID: 29354781 PMCID: PMC5774336 DOI: 10.1016/j.jacbts.2017.06.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 11/30/2022]
Abstract
Cardiovascular disease-related deaths frequently arise from arrhythmias, but treatment options are limited due to perilous side effects of commonly used antiarrhythmic drugs. Cardiac rhythmicity strongly depends on cardiomyocyte Ca2+ handling and prevalent cardiac diseases are causally associated with perturbations in intracellular Ca2+ handling. Therefore, intracellular Ca2+ transporters are lead candidate structures for novel and safer antiarrhythmic therapies. Mitochondria and mitochondrial Ca2+ transport proteins are important regulators of cardiac Ca2+ handling. Here we evaluated the potential of pharmacological activation of mitochondrial Ca2+ uptake for the treatment of cardiac arrhythmia. To this aim,we tested substances that enhance mitochondrial Ca2+ uptake for their ability to suppress arrhythmia in a murine model for ryanodine receptor 2 (RyR2)-mediated catecholaminergic polymorphic ventricular tachycardia (CPVT) in vitro and in vivo and in induced pluripotent stem cell-derived cardiomyocytes from a CPVT patient. In freshly isolated cardiomyocytes of RyR2R4496C/WT mice efsevin, a synthetic agonist of the voltage-dependent anion channel 2 (VDAC2) in the outer mitochondrial membrane, prevented the formation of diastolic Ca2+ waves and spontaneous action potentials. The antiarrhythmic effect of efsevin was abolished by blockade of the mitochondrial Ca2+ uniporter (MCU), but could be reproduced using the natural MCU activator kaempferol. Both mitochondrial Ca2+ uptake enhancers (MiCUps), efsevin and kaempferol, significantly reduced episodes of stress-induced ventricular tachycardia in RyR2R4496C/WT mice in vivo and abolished diastolic, arrhythmogenic Ca2+ events in human iPSC-derived cardiomyocytes.
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Affiliation(s)
- Maria K. Schweitzer
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Fabiola Wilting
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Simon Sedej
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Lisa Dreizehnter
- Department of Medicine (Cardiology), Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Nathan J. Dupper
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California
| | - Qinghai Tian
- Institute for Molecular Cell Biology, University Medical Center, Saarland University, Homburg/Saar, Germany
| | - Alessandra Moretti
- Department of Medicine (Cardiology), Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
| | - Ilaria My
- Department of Medicine (Cardiology), Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Ohyun Kwon
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California
| | - Silvia G. Priori
- Molecular Cardiology, Istituto di ricovero e cura a carattere scientifico (IRCCS) Salvatore Maugeri Foundation, Pavia, Italy
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Karl-Ludwig Laugwitz
- Department of Medicine (Cardiology), Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
| | - Ursula Storch
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Peter Lipp
- Institute for Molecular Cell Biology, University Medical Center, Saarland University, Homburg/Saar, Germany
| | - Andreas Breit
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Michael Mederos y Schnitzler
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
| | - Thomas Gudermann
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
| | - Johann Schredelseker
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
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25
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Mitochondrial Bioenergetics During Ischemia and Reperfusion. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:141-167. [PMID: 28551786 DOI: 10.1007/978-3-319-55330-6_8] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
During ischemia and reperfusion (I/R) mitochondria suffer a deficiency to supply the cardiomyocyte with chemical energy, but also contribute to the cytosolic ionic alterations especially of Ca2+. Their free calcium concentration ([Ca2+]m) mainly depends on mitochondrial entrance through the uniporter (UCam) and extrusion in exchange with Na+ (mNCX) driven by the electrochemical gradient (ΔΨm). Cardiac energetic is frequently estimated by the oxygen consumption, which determines metabolism coupled to ATP production and to the maintaining of ΔΨm. Nevertheless, a better estimation of heart energy consumption is the total heat release associated to ATP hydrolysis, metabolism, and binding reactions, which is measurable either in the presence or the absence of oxygenation or perfusion. Consequently, a mechano-calorimetrical approach on isolated hearts gives a tool to evaluate muscle economy. The mitochondrial role during I/R depends on the injury degree. We investigated the role of the mitochondrial Ca2+ transporters in the energetic of hearts stunned by a model of no-flow I/R in rat hearts. This chapter explores an integrated view of previous and new results which give evidences to the mitochondrial role in cardiac stunning by ischemia o hypoxia, and the influence of thyroid alterations and cardioprotective strategies, such as cardioplegic solutions (high K-low Ca, pyruvate) and the phytoestrogen genistein in both sex. Rat ventricles were perfused in a flow-calorimeter at either 30 °C or 37 °C to continuously measure the left ventricular pressure (LVP) and total heat rate (Ht). A pharmacological treatment was done before exposing to no-flow I and R. The post-ischemic contractile (PICR as %) and energetical (Ht) recovery and muscle economy (Eco: P/Ht) were determined during stunning. The functional interaction between mitochondria (Mit) and sarcoplasmic reticulum (SR) was evaluated with selective mitochondrial inhibitors in hearts reperfused with Krebs-10 mM caffeine-36 mM Na+. The caffeine induced contracture (CIC) was due to SR Ca2+ release, while relaxation mainly depends on mitochondrial Ca2+ uptake since neither SL-NCX nor SERCA are functional under this media. The ratio of area-under-curves over ischemic values (AUC-ΔHt/AUC-ΔLVP) estimates the energetical consumption (EC) to maintain CIC. Relaxation of CIC was accelerated by inhibition of mNCX or by adding the aerobic substrate pyruvate, while both increased EC. Contrarily, relaxation was slowed by cardioplegia (high K-low Ca Krebs) and by inhibition of UCam. Thus, Mit regulate the cytosolic [Ca2+] and SR Ca2+ content. Both, hyperthyroidism (HpT) and hypothyroidism (HypoT) reduced the peak of CIC but increased EC, in spite of improving PICR. Both, CIC and PICR in HpT were also sensitive to inhibition of mNCX or UCam, suggesting that Mit contribute to regulate the SR store and Ca2+ release. The interaction between mitochondria and SR and the energetic consequences were also analyzed for the effects of genistein in hearts exposed to I/R, and for the hypoxia/reoxygenation process. Our results give evidence about the mitochondrial regulation of both PICR and energetic consumption during stunning, through the Ca2+ movement.
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26
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Kohlhaas M, Nickel AG, Maack C. Mitochondrial energetics and calcium coupling in the heart. J Physiol 2017; 595:3753-3763. [PMID: 28105746 DOI: 10.1113/jp273609] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 12/22/2016] [Indexed: 12/21/2022] Open
Abstract
Contraction and relaxation of the heart consume large amounts of energy that need to be replenished by oxidative phosphorylation in mitochondria, and matching energy supply to demand involves the complimentary control of respiration through ADP and Ca2+ . In heart failure, an imbalance between ADP and Ca2+ leads to oxidation of mitochondrial pyridine nucleotides, where NADH oxidation may limit ATP production and contractile function, while NADPH oxidation can induce oxidative stress with consecutive maladaptive remodelling. Understanding the complex mechanisms that disturb this finely tuned equilibrium may aid the development of drugs that could ameliorate the progression of heart failure beyond the classical neuroendocrine inhibition.
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Affiliation(s)
- Michael Kohlhaas
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| | - Alexander G Nickel
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
| | - Christoph Maack
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, Homburg/Saar, Germany
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27
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Wüst RCI, Helmes M, Martin JL, van der Wardt TJT, Musters RJP, van der Velden J, Stienen GJM. Rapid frequency-dependent changes in free mitochondrial calcium concentration in rat cardiac myocytes. J Physiol 2017; 595:2001-2019. [PMID: 28028811 DOI: 10.1113/jp273589] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/16/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Calcium ions regulate mitochondrial ATP production and contractile activity and thus play a pivotal role in matching energy supply and demand in cardiac muscle. The magnitude and kinetics of the changes in free mitochondrial calcium concentration in cardiac myocytes are largely unknown. Rapid stimulation frequency-dependent increases but relatively slow decreases in free mitochondrial calcium concentration were observed in rat cardiac myocytes. This asymmetry caused a rise in the mitochondrial calcium concentration with stimulation frequency. These results provide insight into the mechanisms of mitochondrial calcium uptake and release that are important in healthy and diseased myocardium. ABSTRACT Calcium ions regulate mitochondrial ATP production and contractile activity and thus play a pivotal role in matching energy supply and demand in cardiac muscle. Little is known about the magnitude and kinetics of the changes in free mitochondrial calcium concentration in cardiomyocytes. Using adenoviral infection, a ratiometric mitochondrially targeted Förster resonance energy transfer (FRET)-based calcium indicator (4mtD3cpv, MitoCam) was expressed in cultured adult rat cardiomyocytes and the free mitochondrial calcium concentration ([Ca2+ ]m ) was measured at different stimulation frequencies (0.1-4 Hz) and external calcium concentrations (1.8-3.6 mm) at 37°C. Cytosolic calcium concentrations were assessed under the same experimental conditions in separate experiments using Fura-4AM. The increases in [Ca2+ ]m during electrical stimulation at 0.1 Hz were rapid (rise time = 49 ± 2 ms), while the decreases in [Ca2+ ]m occurred more slowly (decay half time = 1.17 ± 0.07 s). Model calculations confirmed that this asymmetry caused the rise in [Ca2+ ]m during diastole observed at elevated stimulation frequencies. Inhibition of the mitochondrial sodium-calcium exchanger (mNCE) resulted in a rise in [Ca2+ ]m at baseline and, paradoxically, in an acceleration of Ca2+ release. IN CONCLUSION rapid increases in [Ca2+ ]m allow for fast adjustment of mitochondrial ATP production to increases in myocardial demand on a beat-to-beat basis and mitochondrial calcium release depends on mNCE activity and mitochondrial calcium buffering.
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Affiliation(s)
- Rob C I Wüst
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Centre, Amsterdam, the Netherlands
| | - Michiel Helmes
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Centre, Amsterdam, the Netherlands.,IonOptix LLC, Milton, MA, USA
| | - Jody L Martin
- Cell and Molecular Physiology, Loyola University, Chicago, IL, USA
| | - Thomas J T van der Wardt
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Centre, Amsterdam, the Netherlands
| | - René J P Musters
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Centre, Amsterdam, the Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Centre, Amsterdam, the Netherlands
| | - Ger J M Stienen
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Centre, Amsterdam, the Netherlands.,Faculty of Science, Department of Physics and Astronomy, VU University, Amsterdam, the Netherlands
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28
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5-HTR3 and 5-HTR4 located on the mitochondrial membrane and functionally regulated mitochondrial functions. Sci Rep 2016; 6:37336. [PMID: 27874067 PMCID: PMC5118798 DOI: 10.1038/srep37336] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/25/2016] [Indexed: 11/29/2022] Open
Abstract
5-HT has been reported to possess significant effects on cardiac activities, but activation of 5-HTR on the cell membrane failed to illustrate the controversial cardiac reaction. Because 5-HT constantly comes across the cell membrane via 5-HT transporter (5-HTT) into the cytoplasm, whether 5-HTR is functional present on the cellular organelles is unknown. Here we show 5-HTR3 and 5-HTR4 were located in cardiac mitochondria, and regulated mitochondrial activities and cellular functions. Knock down 5-HTR3 and 5-HTR4 in neonatal cardiomyocytes resulted in significant increase of cell damage in response to hypoxia, and also led to alternation in heart beating. Activation of 5-HTR4 attenuated mitochondrial Ca2+ uptake under the both normoxic and hypoxic conditions, whereas 5-HTR3 augmented Ca2+ uptake only under hypoxia. 5-HTR3 and 5-HTR4 exerted the opposite effects on the mitochondrial respiration: 5-HTR3 increased RCR (respiration control ratio), but 5-HTR4 reduced RCR. Moreover, activation of 5-HTR3 and 5-HTR4 both significantly inhibited the opening of mPTP. Our results provided the first evidence that 5-HTR as a GPCR and an ion channel, functionally expressed in mitochondria and participated in the mitochondria function and regulation to maintain homeostasis of mitochondrial [Ca2+], ROS, and ATP generation efficiency in cardiomyocytes in response to stress and O2 tension.
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29
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Hohendanner F, DeSantiago J, Heinzel FR, Blatter LA. Dyssynchronous calcium removal in heart failure-induced atrial remodeling. Am J Physiol Heart Circ Physiol 2016; 311:H1352-H1359. [PMID: 27694214 DOI: 10.1152/ajpheart.00375.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 09/26/2016] [Indexed: 11/22/2022]
Abstract
We tested the hypothesis that in atrial myocytes from a rabbit left ventricular heart failure (HF) model, spatial inhomogeneity and temporal dyssynchrony of Ca removal during excitation-contraction coupling together with increased Na/Ca exchange (NCX) activity generate a substrate for proarrhythmic Ca release. Ca removal occurs via Ca reuptake into the sarcoplasmic reticulum and extrusion via NCX exclusively in the cell periphery since rabbit atrial myocytes lack transverse tubules. Ca removal kinetics were assessed by the time constant τ of decay of local peripheral subsarcolemmal (SS) and central (CT) action potential (AP)-induced Ca transients (CaTs) recorded in confocal line scan mode (using Fluo-4). Spatial and temporal dyssynchrony of Ca removal was quantified by CV TAU, defined as the standard deviation of local τ along the transverse cell axis divided by mean τ. In normal cells CT CaT decline was slower compared with the SS domain, while in HF cells decline was accelerated, became equal in SS and CT regions, and a significant increase of CV TAU indicated an increased Ca removal dyssynchrony. In HF atrial cells NCX upregulation was accompanied by an overall higher incidence of spontaneous Ca waves and a higher propensity of arrhythmogenic Ca waves, defined as waves that triggered APs due to NCX-mediated membrane depolarization. NCX inhibition normalized CV TAU in HF atrial cells and decreased the propensity of Ca waves. In summary, HF atrial myocytes show accelerated but dyssynchronous diastolic Ca removal and altered sarcoplasmic reticulum Ca-ATPase (SERCA) and NCX activity that result in increased susceptibility to arrhythmia.
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Affiliation(s)
- F Hohendanner
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, Illinois
| | - J DeSantiago
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, Illinois
| | - F R Heinzel
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, Illinois
| | - L A Blatter
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, Illinois
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30
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Tse G, Yan BP, Chan YWF, Tian XY, Huang Y. Reactive Oxygen Species, Endoplasmic Reticulum Stress and Mitochondrial Dysfunction: The Link with Cardiac Arrhythmogenesis. Front Physiol 2016; 7:313. [PMID: 27536244 PMCID: PMC4971160 DOI: 10.3389/fphys.2016.00313] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/11/2016] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Cardiac arrhythmias represent a significant problem globally, leading to cerebrovascular accidents, myocardial infarction, and sudden cardiac death. There is increasing evidence to suggest that increased oxidative stress from reactive oxygen species (ROS), which is elevated in conditions such as diabetes and hypertension, can lead to arrhythmogenesis. METHOD A literature review was undertaken to screen for articles that investigated the effects of ROS on cardiac ion channel function, remodeling and arrhythmogenesis. RESULTS Prolonged endoplasmic reticulum stress is observed in heart failure, leading to increased production of ROS. Mitochondrial ROS, which is elevated in diabetes and hypertension, can stimulate its own production in a positive feedback loop, termed ROS-induced ROS release. Together with activation of mitochondrial inner membrane anion channels, it leads to mitochondrial depolarization. Abnormal function of these organelles can then activate downstream signaling pathways, ultimately culminating in altered function or expression of cardiac ion channels responsible for generating the cardiac action potential (AP). Vascular and cardiac endothelial cells become dysfunctional, leading to altered paracrine signaling to influence the electrophysiology of adjacent cardiomyocytes. All of these changes can in turn produce abnormalities in AP repolarization or conduction, thereby increasing likelihood of triggered activity and reentry. CONCLUSION ROS plays a significant role in producing arrhythmic substrate. Therapeutic strategies targeting upstream events include production of a strong reducing environment or the use of pharmacological agents that target organelle-specific proteins and ion channels. These may relieve oxidative stress and in turn prevent arrhythmic complications in patients with diabetes, hypertension, and heart failure.
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Affiliation(s)
- Gary Tse
- Li Ka Shing Faculty of Medicine, School of Biomedical Sciences, University of Hong KongHong Kong, China
- Department of Medicine and Therapeutics, Faculty of Medicine, Chinese University of Hong KongHong Kong, China
| | - Bryan P. Yan
- Department of Medicine and Therapeutics, Faculty of Medicine, Chinese University of Hong KongHong Kong, China
- Department of Epidemiology and Preventive Medicine, Monash UniversityMelbourne, VIC, Australia
| | - Yin W. F. Chan
- Department of Psychology, School of Biological Sciences, University of CambridgeCambridge, UK
| | - Xiao Yu Tian
- Faculty of Medicine, School of Biomedical Sciences, Chinese University of Hong KongHong Kong, China
| | - Yu Huang
- Faculty of Medicine, School of Biomedical Sciences, Chinese University of Hong KongHong Kong, China
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31
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Zhou J, Dhakal K, Yi J. Mitochondrial Ca(2+) uptake in skeletal muscle health and disease. SCIENCE CHINA-LIFE SCIENCES 2016; 59:770-6. [PMID: 27430885 PMCID: PMC6168075 DOI: 10.1007/s11427-016-5089-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 06/07/2016] [Indexed: 11/09/2022]
Abstract
Muscle uses Ca2+ as a messenger to control contraction and relies on ATP to maintain the intracellular Ca2+ homeostasis. Mitochondria are the major sub-cellular organelle of ATP production. With a negative inner membrane potential, mitochondria take up Ca2+ from their surroundings, a process called mitochondrial Ca2+ uptake. Under physiological conditions, Ca2+ uptake into mitochondria promotes ATP production. Excessive uptake causes mitochondrial Ca2+ overload, which activates downstream adverse responses leading to cell dysfunction. Moreover, mitochondrial Ca2+ uptake could shape spatio-temporal patterns of intracellular Ca2+ signaling. Malfunction of mitochondrial Ca2+ uptake is implicated in muscle degeneration. Unlike non-excitable cells, mitochondria in muscle cells experience dramatic changes of intracellular Ca2+ levels. Besides the sudden elevation of Ca2+ level induced by action potentials, Ca2+ transients in muscle cells can be as short as a few milliseconds during a single twitch or as long as minutes during tetanic contraction, which raises the question whether mitochondrial Ca2+ uptake is fast and big enough to shape intracellular Ca2+ signaling during excitation-contraction coupling and creates technical challenges for quantification of the dynamic changes of Ca2+ inside mitochondria. This review focuses on characterization of mitochondrial Ca2+ uptake in skeletal muscle and its role in muscle physiology and diseases.
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Affiliation(s)
- Jingsong Zhou
- Kansas City University of Medicine and Bioscience, Dybedal Research Center, Kansas City, MO, 64106, USA.
| | - Kamal Dhakal
- Kansas City University of Medicine and Bioscience, Dybedal Research Center, Kansas City, MO, 64106, USA
| | - Jianxun Yi
- Kansas City University of Medicine and Bioscience, Dybedal Research Center, Kansas City, MO, 64106, USA
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32
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Hohendanner F, Maxwell JT, Blatter LA. Cytosolic and nuclear calcium signaling in atrial myocytes: IP3-mediated calcium release and the role of mitochondria. Channels (Austin) 2016; 9:129-38. [PMID: 25891132 DOI: 10.1080/19336950.2015.1040966] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In rabbit atrial myocytes Ca signaling has unique features due to the lack of transverse (t) tubules, the spatial arrangement of mitochondria and the contribution of inositol-1,4,5-trisphosphate (IP3) receptor-induced Ca release (IICR). During excitation-contraction coupling action potential-induced elevation of cytosolic [Ca] originates in the cell periphery from Ca released from the junctional sarcoplasmic reticulum (j-SR) and then propagates by Ca-induced Ca release from non-junctional (nj-) SR toward the cell center. The subsarcolemmal region between j-SR and the first array of nj-SR Ca release sites is devoid of mitochondria which results in a rapid propagation of activation through this domain, whereas the subsequent propagation through the nj-SR network occurs at a velocity typical for a propagating Ca wave. Inhibition of mitochondrial Ca uptake with the Ca uniporter blocker Ru360 accelerates propagation and increases the amplitude of Ca transients (CaTs) originating from nj-SR. Elevation of cytosolic IP3 levels by rapid photolysis of caged IP3 has profound effects on the magnitude of subcellular CaTs with increased Ca release from nj-SR and enhanced CaTs in the nuclear compartment. IP3 uncaging restricted to the nucleus elicites 'mini'-Ca waves that remain confined to this compartment. Elementary IICR events (Ca puffs) preferentially originate in the nucleus in close physical association with membrane structures of the nuclear envelope and the nucleoplasmic reticulum. The data suggest that in atrial myocytes the nucleus is an autonomous Ca signaling domain where Ca dynamics are primarily governed by IICR.
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Key Words
- 2-APB, 2-aminoethoxydiphenyl borate
- AP, action potential
- CICR, Ca-induced Ca release
- CRU, Ca release units
- CT, central
- CaT, Ca transient
- ECC, excitation-contraction coupling
- IICR
- IICR, IP3R-induced Ca release
- IP3
- IP3R, Inositol-1,4,5-trisphosphate receptor
- LCC, L-type Ca channels
- MCU, mitochondrial Ca uniporter
- NE, nuclear envelope
- NFAT, nuclear factor of activated T cells
- NPR, nucleoplasmic reticulum
- RyR, ryanodine receptor
- SR, sarcoplasmic reticulum
- SS, subsarcolemmal
- TF50, time to half-maximal amplitude
- TZ, transition zone.
- [Ca]i, cytosolic Ca concentration
- [Ca]mito, mitochondrial Ca concentration
- atria
- excitation-contraction coupling
- j-SR, junctional SR
- mitochondria
- nj-SR, non-junctional SR
- nuclear calcium
- t-tubule, transverse tubule
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Affiliation(s)
- Felix Hohendanner
- a Department of Molecular Biophysics and Physiology ; Rush University Medical Center ; Chicago , IL USA
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33
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Stary V, Puppala D, Scherrer-Crosbie M, Dillmann WH, Armoundas AA. SERCA2a upregulation ameliorates cellular alternans induced by metabolic inhibition. J Appl Physiol (1985) 2016; 120:865-75. [PMID: 26846549 DOI: 10.1152/japplphysiol.00588.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 01/27/2016] [Indexed: 12/26/2022] Open
Abstract
Cardiac alternans has been associated with the incidence of ventricular tachyarrhythmias and sudden cardiac death. The aim of this study was to investigate the effect of impaired mitochondrial function in the genesis of cellular alternans and to examine whether modulating the sarcoplasmic reticulum (SR) Ca(2+)ameliorates the level of alternans. Cardiomyocytes isolated from control and doxycyline-induced sarco(endo)plasmic reticulum Ca(2+)-ATPase 2a (SERCA2a)-upregulated mice were loaded with two different Ca(2+)indicators to selectively measure mitochondrial and cytosolic Ca(2+)using a custom-made fluorescence photometry system. The degree of alternans was defined as the alternans ratio (AR) [1 - (small Ca(2+)intensity)/(large Ca(2+)intensity)]. Blocking of complex I and II, cytochrome-coxidase, F0F1synthase, α-ketoglutarate dehydrogenase of the electron transport chain, increased alternans in both control and SERCA2a mice (P< 0.01). Changes in AR in SERCA2a-upregulated mice were significantly less pronounced than those observed in control in seven of nine tested conditions (P< 0.04).N-acetyl-l-cysteine (NAC), rescued alternans in myocytes that were previously exposed to an oxidizing agent (P< 0.001). CGP, an antagonist of the mitochondrial Na(+)-Ca(2+)exchanger, had the most severe effect on AR. Exposure to cyclosporin A, a blocker of the mitochondrial permeability transition pore reduced CGP-induced alternans (P< 0.0001). The major findings of this study are that impairment of mitochondrial Ca(2+)cycling and energy production leads to a higher amplitude of alternans in both control and SERCA2a-upregulated mice, but changes in SERCA2a-upregulated mice are less severe, indicating that SERCA2a mice are more capable of sustaining electrical stability during stress. This suggests a relationship between sarcoplasmic Ca(2+)content and mitochondrial dysfunction during alternans, which may potentially help to understand changes in Ca(2+)signaling in myocytes from diseased hearts, leading to new therapeutic targets.
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Affiliation(s)
- Victoria Stary
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts; Department of Cardiology and Pulmonology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany; and
| | - Dheeraj Puppala
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts
| | | | - Wolfgang H Dillmann
- Department of Medicine, University of California San Diego, La Jolla, California
| | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts;
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Blomeyer CA, Bazil JN, Stowe DF, Dash RK, Camara AKS. Mg(2+) differentially regulates two modes of mitochondrial Ca(2+) uptake in isolated cardiac mitochondria: implications for mitochondrial Ca(2+) sequestration. J Bioenerg Biomembr 2016; 48:175-88. [PMID: 26815005 DOI: 10.1007/s10863-016-9644-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 01/12/2016] [Indexed: 12/14/2022]
Abstract
The manner in which mitochondria take up and store Ca(2+) remains highly debated. Recent experimental and computational evidence has suggested the presence of at least two modes of Ca(2+) uptake and a complex Ca(2+) sequestration mechanism in mitochondria. But how Mg(2+) regulates these different modes of Ca(2+) uptake as well as mitochondrial Ca(2+) sequestration is not known. In this study, we investigated two different ways by which mitochondria take up and sequester Ca(2+) by using two different protocols. Isolated guinea pig cardiac mitochondria were exposed to varying concentrations of CaCl2 in the presence or absence of MgCl2. In the first protocol, A, CaCl2 was added to the respiration buffer containing isolated mitochondria, whereas in the second protocol, B, mitochondria were added to the respiration buffer with CaCl2 already present. Protocol A resulted first in a fast transitory uptake followed by a slow gradual uptake. In contrast, protocol B only revealed a slow and gradual Ca(2+) uptake, which was approximately 40 % of the slow uptake rate observed in protocol A. These two types of Ca(2+) uptake modes were differentially modulated by extra-matrix Mg(2+). That is, Mg(2+) markedly inhibited the slow mode of Ca(2+) uptake in both protocols in a concentration-dependent manner, but not the fast mode of uptake exhibited in protocol A. Mg(2+) also inhibited Na(+)-dependent Ca(2+) extrusion. The general Ca(2+) binding properties of the mitochondrial Ca(2+) sequestration system were reaffirmed and shown to be independent of the mode of Ca(2+) uptake, i.e. through the fast or slow mode of uptake. In addition, extra-matrix Mg(2+) hindered Ca(2+) sequestration. Our results indicate that mitochondria exhibit different modes of Ca(2+) uptake depending on the nature of exposure to extra-matrix Ca(2+), which are differentially sensitive to Mg(2+). The implications of these findings in cardiomyocytes are discussed.
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Affiliation(s)
- Christoph A Blomeyer
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Jason N Bazil
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA.,Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - David F Stowe
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.,Department of Biomedical Engineering, Marquette University, Milwaukee, WI, 53233, USA.,Research Service, Zablocki Veterans Affairs Medical Center, Milwaukee, WI, 53295, USA
| | - Ranjan K Dash
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.,Department of Biomedical Engineering, Marquette University, Milwaukee, WI, 53233, USA
| | - Amadou K S Camara
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
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Winslow RL, Walker MA, Greenstein JL. Modeling calcium regulation of contraction, energetics, signaling, and transcription in the cardiac myocyte. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2015; 8:37-67. [PMID: 26562359 DOI: 10.1002/wsbm.1322] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 09/29/2015] [Accepted: 09/30/2015] [Indexed: 12/11/2022]
Abstract
Calcium (Ca(2+)) plays many important regulatory roles in cardiac muscle cells. In the initial phase of the action potential, influx of Ca(2+) through sarcolemmal voltage-gated L-type Ca(2+) channels (LCCs) acts as a feed-forward signal that triggers a large release of Ca(2+) from the junctional sarcoplasmic reticulum (SR). This Ca(2+) drives heart muscle contraction and pumping of blood in a process known as excitation-contraction coupling (ECC). Triggered and released Ca(2+) also feed back to inactivate LCCs, attenuating the triggered Ca(2+) signal once release has been achieved. The process of ECC consumes large amounts of ATP. It is now clear that in a process known as excitation-energetics coupling, Ca(2+) signals exert beat-to-beat regulation of mitochondrial ATP production that closely couples energy production with demand. This occurs through transport of Ca(2+) into mitochondria, where it regulates enzymes of the tricarboxylic acid cycle. In excitation-signaling coupling, Ca(2+) activates a number of signaling pathways in a feed-forward manner. Through effects on their target proteins, these interconnected pathways regulate Ca(2+) signals in complex ways to control electrical excitability and contractility of heart muscle. In a process known as excitation-transcription coupling, Ca(2+) acting primarily through signal transduction pathways also regulates the process of gene transcription. Because of these diverse and complex roles, experimentally based mechanistic computational models are proving to be very useful for understanding Ca(2+) signaling in the cardiac myocyte.
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Affiliation(s)
- Raimond L Winslow
- Institute for Computational Medicine and Department of Biomedical Engineering, The Johns Hopkins University School of Medicine and Whiting School of Engineering, Baltimore, MD, USA
| | - Mark A Walker
- Institute for Computational Medicine and Department of Biomedical Engineering, The Johns Hopkins University School of Medicine and Whiting School of Engineering, Baltimore, MD, USA
| | - Joseph L Greenstein
- Institute for Computational Medicine and Department of Biomedical Engineering, The Johns Hopkins University School of Medicine and Whiting School of Engineering, Baltimore, MD, USA
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Finkel T, Menazza S, Holmström KM, Parks RJ, Liu J, Sun J, Liu J, Pan X, Murphy E. The ins and outs of mitochondrial calcium. Circ Res 2015; 116:1810-9. [PMID: 25999421 DOI: 10.1161/circresaha.116.305484] [Citation(s) in RCA: 184] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Calcium is thought to play an important role in regulating mitochondrial function. Evidence suggests that an increase in mitochondrial calcium can augment ATP production by altering the activity of calcium-sensitive mitochondrial matrix enzymes. In contrast, the entry of large amounts of mitochondrial calcium in the setting of ischemia-reperfusion injury is thought to be a critical event in triggering cellular necrosis. For many decades, the details of how calcium entered the mitochondria remained a biological mystery. In the past few years, significant progress has been made in identifying the molecular components of the mitochondrial calcium uniporter complex. Here, we review how calcium enters and leaves the mitochondria, the growing insight into the topology, stoichiometry and function of the uniporter complex, and the early lessons learned from some initial mouse models that genetically perturb mitochondrial calcium homeostasis.
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Affiliation(s)
- Toren Finkel
- From the Center for Molecular Medicine (T.F., K.M.H., Julia Liu, Jie Liu) and Systems Biology Center (S.M., R.J.P., J.S., E.M.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Laboratory of Cell Biology, National Center of Biomedical Analysis, Beijing, China (X.P.).
| | - Sara Menazza
- From the Center for Molecular Medicine (T.F., K.M.H., Julia Liu, Jie Liu) and Systems Biology Center (S.M., R.J.P., J.S., E.M.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Laboratory of Cell Biology, National Center of Biomedical Analysis, Beijing, China (X.P.)
| | - Kira M Holmström
- From the Center for Molecular Medicine (T.F., K.M.H., Julia Liu, Jie Liu) and Systems Biology Center (S.M., R.J.P., J.S., E.M.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Laboratory of Cell Biology, National Center of Biomedical Analysis, Beijing, China (X.P.)
| | - Randi J Parks
- From the Center for Molecular Medicine (T.F., K.M.H., Julia Liu, Jie Liu) and Systems Biology Center (S.M., R.J.P., J.S., E.M.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Laboratory of Cell Biology, National Center of Biomedical Analysis, Beijing, China (X.P.)
| | - Julia Liu
- From the Center for Molecular Medicine (T.F., K.M.H., Julia Liu, Jie Liu) and Systems Biology Center (S.M., R.J.P., J.S., E.M.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Laboratory of Cell Biology, National Center of Biomedical Analysis, Beijing, China (X.P.)
| | - Junhui Sun
- From the Center for Molecular Medicine (T.F., K.M.H., Julia Liu, Jie Liu) and Systems Biology Center (S.M., R.J.P., J.S., E.M.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Laboratory of Cell Biology, National Center of Biomedical Analysis, Beijing, China (X.P.)
| | - Jie Liu
- From the Center for Molecular Medicine (T.F., K.M.H., Julia Liu, Jie Liu) and Systems Biology Center (S.M., R.J.P., J.S., E.M.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Laboratory of Cell Biology, National Center of Biomedical Analysis, Beijing, China (X.P.)
| | - Xin Pan
- From the Center for Molecular Medicine (T.F., K.M.H., Julia Liu, Jie Liu) and Systems Biology Center (S.M., R.J.P., J.S., E.M.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Laboratory of Cell Biology, National Center of Biomedical Analysis, Beijing, China (X.P.)
| | - Elizabeth Murphy
- From the Center for Molecular Medicine (T.F., K.M.H., Julia Liu, Jie Liu) and Systems Biology Center (S.M., R.J.P., J.S., E.M.), National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD; and Laboratory of Cell Biology, National Center of Biomedical Analysis, Beijing, China (X.P.).
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Bernardi P, Di Lisa F, Fogolari F, Lippe G. From ATP to PTP and Back: A Dual Function for the Mitochondrial ATP Synthase. Circ Res 2015; 116:1850-62. [PMID: 25999424 DOI: 10.1161/circresaha.115.306557] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mitochondria not only play a fundamental role in heart physiology but are also key effectors of dysfunction and death. This dual role assumes a new meaning after recent advances on the nature and regulation of the permeability transition pore, an inner membrane channel whose opening requires matrix Ca(2+) and is modulated by many effectors including reactive oxygen species, matrix cyclophilin D, Pi (inorganic phosphate), and matrix pH. The recent demonstration that the F-ATP synthase can reversibly undergo a Ca(2+)-dependent transition to form a channel that mediates the permeability transition opens new perspectives to the field. These findings demand a reassessment of the modifications of F-ATP synthase that take place in the heart under pathological conditions and of their potential role in determining the transition of F-ATP synthase from and energy-conserving into an energy-dissipating device.
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Affiliation(s)
- Paolo Bernardi
- From the Department of Biomedical Sciences, University of Padova, Italy (P.B., F.D.L.); and Department of Medical and Biological Sciences (F.F) and Department of Food Science (G.L.), University of Udine, Udine, Italy.
| | - Fabio Di Lisa
- From the Department of Biomedical Sciences, University of Padova, Italy (P.B., F.D.L.); and Department of Medical and Biological Sciences (F.F) and Department of Food Science (G.L.), University of Udine, Udine, Italy
| | - Federico Fogolari
- From the Department of Biomedical Sciences, University of Padova, Italy (P.B., F.D.L.); and Department of Medical and Biological Sciences (F.F) and Department of Food Science (G.L.), University of Udine, Udine, Italy
| | - Giovanna Lippe
- From the Department of Biomedical Sciences, University of Padova, Italy (P.B., F.D.L.); and Department of Medical and Biological Sciences (F.F) and Department of Food Science (G.L.), University of Udine, Udine, Italy
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38
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Ragone MI, Bonazzola P, Colareda GA, Consolini AE. Cardioprotective effect of hyperthyroidism on the stunned rat heart during ischaemia-reperfusion: energetics and role of mitochondria. Exp Physiol 2015; 100:680-97. [DOI: 10.1113/ep085063] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 04/08/2015] [Accepted: 04/07/2015] [Indexed: 12/13/2022]
Affiliation(s)
- María Inés Ragone
- Cátedra de Farmacología, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas; Universidad Nacional de La Plata; Argentina
| | - Patricia Bonazzola
- Cátedra de Biofísica, Facultad de Odontología e Instituto de Investigaciones Cardiológicas, Facultad de Medicina; Universidad de Buenos Aires-CONICET; Argentina
| | - Germán A. Colareda
- Cátedra de Farmacología, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas; Universidad Nacional de La Plata; Argentina
| | - Alicia E. Consolini
- Cátedra de Farmacología, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas; Universidad Nacional de La Plata; Argentina
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Yang KC, Kyle JW, Makielski JC, Dudley SC. Mechanisms of sudden cardiac death: oxidants and metabolism. Circ Res 2015; 116:1937-55. [PMID: 26044249 PMCID: PMC4458707 DOI: 10.1161/circresaha.116.304691] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Accepted: 02/09/2015] [Indexed: 02/07/2023]
Abstract
Ventricular arrhythmia is the leading cause of sudden cardiac death (SCD). Deranged cardiac metabolism and abnormal redox state during cardiac diseases foment arrhythmogenic substrates through direct or indirect modulation of cardiac ion channel/transporter function. This review presents current evidence on the mechanisms linking metabolic derangement and excessive oxidative stress to ion channel/transporter dysfunction that predisposes to ventricular arrhythmias and SCD. Because conventional antiarrhythmic agents aiming at ion channels have proven challenging to use, targeting arrhythmogenic metabolic changes and redox imbalance may provide novel therapeutics to treat or prevent life-threatening arrhythmias and SCD.
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Affiliation(s)
- Kai-Chien Yang
- From the Department of Pharmacology (K.-C.Y.) and Division of Cardiology, Department of Internal Medicine (K.-C.Y.), National Taiwan University Hospital, Taipei, Taiwan; Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison (J.W.K., J.C.M.); and Lifespan Cardiovascular Institute, the Providence VA Medical Center, and Brown University, RI (S.C.D.)
| | - John W Kyle
- From the Department of Pharmacology (K.-C.Y.) and Division of Cardiology, Department of Internal Medicine (K.-C.Y.), National Taiwan University Hospital, Taipei, Taiwan; Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison (J.W.K., J.C.M.); and Lifespan Cardiovascular Institute, the Providence VA Medical Center, and Brown University, RI (S.C.D.)
| | - Jonathan C Makielski
- From the Department of Pharmacology (K.-C.Y.) and Division of Cardiology, Department of Internal Medicine (K.-C.Y.), National Taiwan University Hospital, Taipei, Taiwan; Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison (J.W.K., J.C.M.); and Lifespan Cardiovascular Institute, the Providence VA Medical Center, and Brown University, RI (S.C.D.).
| | - Samuel C Dudley
- From the Department of Pharmacology (K.-C.Y.) and Division of Cardiology, Department of Internal Medicine (K.-C.Y.), National Taiwan University Hospital, Taipei, Taiwan; Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison (J.W.K., J.C.M.); and Lifespan Cardiovascular Institute, the Providence VA Medical Center, and Brown University, RI (S.C.D.).
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40
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Boyman L, Chikando AC, Williams GSB, Khairallah RJ, Kettlewell S, Ward CW, Smith GL, Kao JPY, Lederer WJ. Calcium movement in cardiac mitochondria. Biophys J 2015; 107:1289-301. [PMID: 25229137 DOI: 10.1016/j.bpj.2014.07.045] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 07/08/2014] [Accepted: 07/22/2014] [Indexed: 10/24/2022] Open
Abstract
Existing theory suggests that mitochondria act as significant, dynamic buffers of cytosolic calcium ([Ca(2+)]i) in heart. These buffers can remove up to one-third of the Ca(2+) that enters the cytosol during the [Ca(2+)]i transients that underlie contractions. However, few quantitative experiments have been presented to test this hypothesis. Here, we investigate the influence of Ca(2+) movement across the inner mitochondrial membrane during both subcellular and global cellular cytosolic Ca(2+) signals (i.e., Ca(2+) sparks and [Ca(2+)]i transients, respectively) in isolated rat cardiomyocytes. By rapidly turning off the mitochondria using depolarization of the inner mitochondrial membrane potential (ΔΨm), the role of the mitochondria in buffering cytosolic Ca(2+) signals was investigated. We show here that rapid loss of ΔΨm leads to no significant changes in cytosolic Ca(2+) signals. Second, we make direct measurements of mitochondrial [Ca(2+)] ([Ca(2+)]m) using a mitochondrially targeted Ca(2+) probe (MityCam) and these data suggest that [Ca(2+)]m is near the [Ca(2+)]i level (∼100 nM) under quiescent conditions. These two findings indicate that although the mitochondrial matrix is fully buffer-capable under quiescent conditions, it does not function as a significant dynamic buffer during physiological Ca(2+) signaling. Finally, quantitative analysis using a computational model of mitochondrial Ca(2+) cycling suggests that mitochondrial Ca(2+) uptake would need to be at least ∼100-fold greater than the current estimates of Ca(2+) influx for mitochondria to influence measurably cytosolic [Ca(2+)] signals under physiological conditions. Combined, these experiments and computational investigations show that mitochondrial Ca(2+) uptake does not significantly alter cytosolic Ca(2+) signals under normal conditions and indicates that mitochondria do not act as important dynamic buffers of [Ca(2+)]i under physiological conditions in heart.
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Affiliation(s)
- Liron Boyman
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland; Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Aristide C Chikando
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland; Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - George S B Williams
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland; Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland; School of Systems Biology, George Mason University, Fairfax, Virginia
| | - Ramzi J Khairallah
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland; University of Maryland School of Nursing, Baltimore, Maryland; Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois
| | - Sarah Kettlewell
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, G12 8QQ Glasgow, United Kingdom
| | - Christopher W Ward
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland; University of Maryland School of Nursing, Baltimore, Maryland
| | - Godfrey L Smith
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, G12 8QQ Glasgow, United Kingdom
| | - Joseph P Y Kao
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland; Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - W Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland; Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland.
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Mistlberger G, Pawlak M, Bakker E, Klimant I. Photodynamic optical sensor for buffer capacity and pH based on hydrogel-incorporated spiropyran. Chem Commun (Camb) 2015; 51:4172-5. [DOI: 10.1039/c4cc07821g] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The kinetics of a light activated proton extraction correlates with the buffer capacity of a sample at a given pH.
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Affiliation(s)
- G. Mistlberger
- Graz University of Technology
- Institue of Analytical Chemistry and Food Chemistry
- 8010 Graz
- Austria
| | - M. Pawlak
- University of Geneva
- Department of Inorganic and Analytical Chemistry
- 1211 Geneva 4
- Switzerland
| | - E. Bakker
- University of Geneva
- Department of Inorganic and Analytical Chemistry
- 1211 Geneva 4
- Switzerland
| | - I. Klimant
- Graz University of Technology
- Institue of Analytical Chemistry and Food Chemistry
- 8010 Graz
- Austria
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42
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Hohendanner F, Walther S, Maxwell JT, Kettlewell S, Awad S, Smith GL, Lonchyna VA, Blatter LA. Inositol-1,4,5-trisphosphate induced Ca2+ release and excitation-contraction coupling in atrial myocytes from normal and failing hearts. J Physiol 2014; 593:1459-77. [PMID: 25416623 DOI: 10.1113/jphysiol.2014.283226] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 11/10/2014] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Impaired calcium (Ca(2+)) signalling is the main contributor to depressed ventricular contractile function and occurrence of arrhythmia in heart failure (HF). Here we report that in atrial cells of a rabbit HF model, Ca(2+) signalling is enhanced and we identified the underlying cellular mechanisms. Enhanced Ca(2+) transients (CaTs) are due to upregulation of inositol-1,4,5-trisphosphate receptor induced Ca(2+) release (IICR) and decreased mitochondrial Ca(2+) sequestration. Enhanced IICR, however, together with an increased activity of the sodium-calcium exchange mechanism, also facilitates spontaneous Ca(2+) release in form of arrhythmogenic Ca(2+) waves and spontaneous action potentials, thus enhancing the arrhythmogenic potential of atrial cells. Our data show that enhanced Ca(2+) signalling in HF provides atrial cells with a mechanism to improve ventricular filling and to maintain cardiac output, but also increases the susceptibility to develop atrial arrhythmias facilitated by spontaneous Ca(2+) release. ABSTRACT We studied excitation-contraction coupling (ECC) and inositol-1,4,5-triphosphate (IP3)-dependent Ca(2+) release in normal and heart failure (HF) rabbit atrial cells. Left ventricular HF was induced by combined volume and pressure overload. In HF atrial myocytes diastolic [Ca(2+)]i was increased, action potential (AP)-induced Ca(2+) transients (CaTs) were larger in amplitude, primarily due to enhanced Ca(2+) release from central non-junctional sarcoplasmic reticulum (SR) and centripetal propagation of activation was accelerated, whereas HF ventricular CaTs were depressed. The larger CaTs were due to enhanced IP3 receptor-induced Ca(2+) release (IICR) and reduced mitochondrial Ca(2+) buffering, consistent with a reduced mitochondrial density and Ca(2+) uptake capacity in HF. Elementary IP3 receptor-mediated Ca(2+) release events (Ca(2+) puffs) were more frequent in HF atrial myoctes and were detected more often in central regions of the non-junctional SR compared to normal cells. HF cells had an overall higher frequency of spontaneous Ca(2+) waves and a larger fraction of waves (termed arrhythmogenic Ca(2+) waves) triggered APs and global CaTs. The higher propensity of arrhythmogenic Ca(2+) waves resulted from the combined action of enhanced IICR and increased activity of sarcolemmal Na(+)-Ca(2+) exchange depolarizing the cell membrane. In conclusion, the data support the hypothesis that in atrial myocytes from hearts with left ventricular failure, enhanced CaTs during ECC exert positive inotropic effects on atrial contractility which facilitates ventricular filling and contributes to maintaining cardiac output. However, HF atrial cells were also more susceptible to developing arrhythmogenic Ca(2+) waves which might form the substrate for atrial rhythm disorders frequently encountered in HF.
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Affiliation(s)
- Felix Hohendanner
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, IL, 60612, USA
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43
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The mitochondrial Ca(2+) uniporter complex. J Mol Cell Cardiol 2014; 78:3-8. [PMID: 25463276 DOI: 10.1016/j.yjmcc.2014.11.015] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Revised: 11/13/2014] [Accepted: 11/14/2014] [Indexed: 01/09/2023]
Abstract
Calcium influx into the mitochondrial matrix plays important roles in the regulation of cell death pathways, bioenergetics and cytoplasmic Ca(2+) signals. During the last few years, several molecular components of the inner membrane mitochondrial Ca(2+) uniporter, the dominant pathway for Ca(2+) influx into the mitochondrial matrix, have been identified. The uniporter is now recognized as a complex of proteins that include a Ca(2+) pore forming component and accessory proteins that are either required for its channel activity or regulate it under various conditions. This review summarizes recent discoveries about the molecular basis of the uniporter complex. This article is part of a Special Issue entitled "Mitochondria: From Basic Mitochondrial Biology to Cardiovascular Disease."
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Harrington JL, Murphy E. The mitochondrial calcium uniporter: mice can live and die without it. J Mol Cell Cardiol 2014; 78:46-53. [PMID: 25451167 DOI: 10.1016/j.yjmcc.2014.10.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Revised: 10/23/2014] [Accepted: 10/26/2014] [Indexed: 01/27/2023]
Abstract
Calcium is of critical importance to mitochondrial and cell function, and calcium signaling is highly localized in the cell. When stimulated, mitochondria are capable of rapidly taking up calcium, affecting both matrix energetics within mitochondria and shaping the amplitude and frequency of cytosolic calcium "waves". During pathological conditions a large increase in mitochondrial calcium levels is thought to activate the mitochondrial permeability transition pore, resulting in cell death. The protein responsible for mitochondrial calcium uptake, the mitochondrial calcium uniporter (MCU), was identified in 2011 and its molecular elucidation has stimulated and invigorated research in this area. MCU knockout mice have been created, a variety of other regulators have been identified, and a disease phenotype in humans has been attributed to the loss of a uniporter regulator. In the three years since its molecular elucidation, further research into the MCU has revealed a complex uniporter, and raised many questions about its physiologic and pathologic cell roles. This article is part of a Special Issue entitled "Mitochondria: From Basic Mitochondrial Biology to Cardiovascular Disease".
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45
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Fernández-Sada E, Silva-Platas C, Villegas CA, Rivero SL, Willis BC, García N, Garza JR, Oropeza-Almazán Y, Valverde CA, Mazzocchi G, Zazueta C, Torre-Amione G, García-Rivas G. Cardiac responses to β-adrenoceptor stimulation is partly dependent on mitochondrial calcium uniporter activity. Br J Pharmacol 2014; 171:4207-21. [PMID: 24628066 DOI: 10.1111/bph.12684] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 02/06/2014] [Accepted: 03/01/2014] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE Despite the importance of mitochondrial Ca(2+) to metabolic regulation and cell physiology, little is known about the mechanisms that regulate Ca(2+) entry into the mitochondria. Accordingly, we established a system to determine the role of the mitochondrial Ca(2+) uniporter in an isolated heart model, at baseline and during increased workload following β-adrenoceptor stimulation. EXPERIMENTAL APPROACH Cardiac contractility, oxygen consumption and intracellular Ca(2+) transients were measured in ex vivo perfused murine hearts. Ru360 and spermine were used to modify mitochondrial Ca(2+) uniporter activity. Changes in mitochondrial Ca(2+) content and energetic phosphate metabolite levels were determined. KEY RESULTS The addition of Ru360 , a selective inhibitor of the mitochondrial Ca(2+) uniporter, induced progressively and sustained negative inotropic effects that were dose-dependent with an EC50 of 7 μM. Treatment with spermine, a uniporter agonist, showed a positive inotropic effect that was blocked by Ru360 . Inotropic stimulation with isoprenaline elevated oxygen consumption (2.7-fold), Ca(2+) -dependent activation of pyruvate dehydrogenase (5-fold) and mitochondrial Ca(2+) content (2.5-fold). However, in Ru360 -treated hearts, this parameter was attenuated. In addition, β-adrenoceptor stimulation in the presence of Ru360 did not affect intracellular Ca(2+) handling, PKA or Ca(2+) /calmodulin-dependent PK signalling. CONCLUSIONS AND IMPLICATIONS Inhibition of the mitochondrial Ca(2+) uniporter decreases β-adrenoceptor response, uncoupling between workload and production of energetic metabolites. Our results support the hypothesis that the coupling of workload and energy supply is partly dependent on mitochondrial Ca(2+) uniporter activity.
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Affiliation(s)
- E Fernández-Sada
- Cátedra de Cardiología y Medicina Vascular, Escuela de Medicina, Tecnológico de Monterrey, Monterrey, Nuevo León, México
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46
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Diversity of mitochondrial Ca²⁺ signaling in rat neonatal cardiomyocytes: evidence from a genetically directed Ca²⁺ probe, mitycam-E31Q. Cell Calcium 2014; 56:133-46. [PMID: 24994483 DOI: 10.1016/j.ceca.2014.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 06/03/2014] [Accepted: 06/07/2014] [Indexed: 11/24/2022]
Abstract
I(Ca)-gated Ca(2+) release (CICR) from the cardiac SR is the main mechanism mediating the rise of cytosolic Ca(2+), but the extent to which mitochondria contribute to the overall Ca(2+) signaling remains controversial. To examine the possible role of mitochondria in Ca(2+) signaling, we developed a low affinity mitochondrial Ca(2+) probe, mitycam-E31Q (300-500 MOI, 48-72h) and used it in conjunction with Fura-2AM to obtain simultaneous TIRF images of mitochondrial and cytosolic Ca(2+) in cultured neonatal rat cardiomyocytes. Mitycam-E31Q staining of adult feline cardiomyocytes showed the typical mitochondrial longitudinal fluorescent bandings similar to that of TMRE staining, while neonatal rat cardiomyocytes had a disorganized tubular or punctuate appearance. Caffeine puffs produced rapid increases in cytosolic Ca(2+) while simultaneously measured global mitycam-E31Q signals decreased more slowly (increased mitochondrial Ca(2+)) before decaying to baseline levels. Similar, but oscillating mitycam-E31Q signals were seen in spontaneously pacing cells. Withdrawal of Na(+) increased global cytosolic and mitochondrial Ca(2+) signals in one population of mitochondria, but unexpectedly decreased it (release of Ca(2+)) in another mitochondrial population. Such mitochondrial Ca(2+) release signals were seen not only during long lasting Na(+) withdrawal, but also when Ca(2+) loaded cells were exposed to caffeine-puffs, and during spontaneous rhythmic beating. Thus, mitochondrial Ca(2+) transients appear to activate with a delay following the cytosolic rise of Ca(2+) and show diversity in subpopulations of mitochondria that could contribute to the plasticity of mitochondrial Ca(2+) signaling.
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Yang KC, Bonini MG, Dudley SC. Mitochondria and arrhythmias. Free Radic Biol Med 2014; 71:351-361. [PMID: 24713422 PMCID: PMC4096785 DOI: 10.1016/j.freeradbiomed.2014.03.033] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 03/21/2014] [Accepted: 03/24/2014] [Indexed: 12/31/2022]
Abstract
Mitochondria are essential to providing ATP, thereby satisfying the energy demand of the incessant electrical activity and contractile action of cardiac muscle. Emerging evidence indicates that mitochondrial dysfunction can adversely affect cardiac electrical functioning by impairing the intracellular ion homeostasis and membrane excitability through reduced ATP production and excessive reactive oxygen species (ROS) generation, resulting in increased propensity to cardiac arrhythmias. In this review, the molecular mechanisms linking mitochondrial dysfunction to cardiac arrhythmias are discussed with an emphasis on the impact of increased mitochondrial ROS on the cardiac ion channels and transporters that are critical to maintaining normal electromechanical functioning of the cardiomyocytes. The potential of using mitochondria-targeted antioxidants as a novel antiarrhythmia therapy is highlighted.
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Affiliation(s)
- Kai-Chien Yang
- Lifespan Cardiovascular Institute, Providence VA Medical Center, and Brown University, Providence, RI 02903, USA
| | - Marcelo G Bonini
- Department of Medicine/Cardiology, University of Illinois at Chicago, Chicago, IL 60612, USA; Department of Pathology, and University of Illinois at Chicago, Chicago, IL 60612, USA; Department of Pharmacology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Samuel C Dudley
- Lifespan Cardiovascular Institute, Providence VA Medical Center, and Brown University, Providence, RI 02903, USA.
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Dague E, Genet G, Lachaize V, Guilbeau-Frugier C, Fauconnier J, Mias C, Payré B, Chopinet L, Alsteens D, Kasas S, Severac C, Thireau J, Heymes C, Honton B, Lacampagne A, Pathak A, Sénard JM, Galés C. Atomic force and electron microscopic-based study of sarcolemmal surface of living cardiomyocytes unveils unexpected mitochondrial shift in heart failure. J Mol Cell Cardiol 2014; 74:162-72. [PMID: 24839910 DOI: 10.1016/j.yjmcc.2014.05.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/07/2014] [Accepted: 05/08/2014] [Indexed: 10/25/2022]
Abstract
Loss of T-tubules (TT), sarcolemmal invaginations of cardiomyocytes (CMs), was recently identified as a general heart failure (HF) hallmark. However, whether TT per se or the overall sarcolemma is altered during HF process is still unknown. In this study, we directly examined sarcolemmal surface topography and physical properties using Atomic Force Microscopy (AFM) in living CMs from healthy and failing mice hearts. We confirmed the presence of highly organized crests and hollows along myofilaments in isolated healthy CMs. Sarcolemma topography was tightly correlated with elasticity, with crests stiffer than hollows and related to the presence of few packed subsarcolemmal mitochondria (SSM) as evidenced by electron microscopy. Three days after myocardial infarction (MI), CMs already exhibit an overall sarcolemma disorganization with general loss of crests topography thus becoming smooth and correlating with a decreased elasticity while interfibrillar mitochondria (IFM), myofilaments alignment and TT network were unaltered. End-stage post-ischemic condition (15days post-MI) exacerbates overall sarcolemma disorganization with, in addition to general loss of crest/hollow periodicity, a significant increase of cell surface stiffness. Strikingly, electron microscopy revealed the total depletion of SSM while some IFM heaps could be visualized beneath the membrane. Accordingly, mitochondrial Ca(2+) studies showed a heterogeneous pattern between SSM and IFM in healthy CMs which disappeared in HF. In vitro, formamide-induced sarcolemmal stress on healthy CMs phenocopied post-ischemic kinetics abnormalities and revealed initial SSM death and crest/hollow disorganization followed by IFM later disarray which moved toward the cell surface and structured heaps correlating with TT loss. This study demonstrates that the loss of crest/hollow organization of CM surface in HF occurs early and precedes disruption of the TT network. It also highlights a general stiffness increased of the CM surface most likely related to atypical IFM heaps while SSM died during HF process. Overall, these results indicate that initial sarcolemmal stress leading to SSM death could underlie subsequent TT disarray and HF setting.
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Affiliation(s)
- Etienne Dague
- CNRS, LAAS, F-31400 Toulouse, France; CNRS, ITAV-USR3505, Toulouse, France; Université de Toulouse, ITAV, LAAS, F-31400 Toulouse France.
| | - Gaël Genet
- Institut des Maladies Métaboliques et Cardiovasculaires, INSERM UMR1048, Toulouse, France
| | | | - Céline Guilbeau-Frugier
- Institut des Maladies Métaboliques et Cardiovasculaires, INSERM UMR1048, Toulouse, France; Department of Histopathology, Centre Hospitalier Universitaire de Toulouse, 31432 Toulouse, France
| | - Jérémy Fauconnier
- INSERM U1046, Université Montpellier 1, Université Montpellier 2, Montpellier, France
| | - Céline Mias
- Institut des Maladies Métaboliques et Cardiovasculaires, INSERM UMR1048, Toulouse, France
| | - Bruno Payré
- Centre de Microscopie Électronique Appliquée à la Biologie, Faculté de Médecine Rangueil, 31062 Toulouse, France
| | - Louise Chopinet
- CNRS, LAAS, F-31400 Toulouse, France; CNRS, IPBS-UMR5089, F-31077 Toulouse, France
| | - David Alsteens
- Institute of Life Sciences, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Sandor Kasas
- Department of Cellular Biology and Morphology, Université de Lausanne, Institut de Physique des Systèmes Biologiques, École Polytechnique Fédérale de Lausanne, Switzerland
| | - Childerick Severac
- CNRS, ITAV-USR3505, Toulouse, France; Université de Toulouse, ITAV, LAAS, F-31400 Toulouse France
| | - Jérôme Thireau
- INSERM U1046, Université Montpellier 1, Université Montpellier 2, Montpellier, France
| | - Christophe Heymes
- Institut des Maladies Métaboliques et Cardiovasculaires, INSERM UMR1048, Toulouse, France
| | - Benjamin Honton
- Institut des Maladies Métaboliques et Cardiovasculaires, INSERM UMR1048, Toulouse, France
| | - Alain Lacampagne
- INSERM U1046, Université Montpellier 1, Université Montpellier 2, Montpellier, France
| | - Atul Pathak
- Institut des Maladies Métaboliques et Cardiovasculaires, INSERM UMR1048, Toulouse, France; Department of Clinical Pharmacology, Centre Hospitalier Universitaire de Toulouse, F-31432 Toulouse, France
| | - Jean-Michel Sénard
- Institut des Maladies Métaboliques et Cardiovasculaires, INSERM UMR1048, Toulouse, France; Department of Clinical Pharmacology, Centre Hospitalier Universitaire de Toulouse, F-31432 Toulouse, France
| | - Céline Galés
- CNRS, ITAV-USR3505, Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, INSERM UMR1048, Toulouse, France.
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Li Q, Pogwizd SM, Prabhu SD, Zhou L. Inhibiting Na+/K+ ATPase can impair mitochondrial energetics and induce abnormal Ca2+ cycling and automaticity in guinea pig cardiomyocytes. PLoS One 2014; 9:e93928. [PMID: 24722410 PMCID: PMC3983106 DOI: 10.1371/journal.pone.0093928] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 03/11/2014] [Indexed: 12/22/2022] Open
Abstract
Cardiac glycosides have been used for the treatment of heart failure because of their capabilities of inhibiting Na+/K+ ATPase (NKA), which raises [Na+]i and attenuates Ca2+ extrusion via the Na+/Ca2+ exchanger (NCX), causing [Ca2+]i elevation. The resulting [Ca2+]i accumulation further enhances Ca2+-induced Ca2+ release, generating the positive inotropic effect. However, cardiac glycosides have some toxic and side effects such as arrhythmogenesis, confining their extensive clinical applications. The mechanisms underlying the proarrhythmic effect of glycosides are not fully understood. Here we investigated the mechanisms by which glycosides could cause cardiac arrhythmias via impairing mitochondrial energetics using an integrative computational cardiomyocyte model. In the simulations, the effect of glycosides was mimicked by blocking NKA activity. Results showed that inhibiting NKA not only impaired mitochondrial Ca2+ retention (thus suppressed reactive oxygen species (ROS) scavenging) but also enhanced oxidative phosphorylation (thus increased ROS production) during the transition of increasing workload, causing oxidative stress. Moreover, concurrent blocking of mitochondrial Na+/Ca2+ exchanger, but not enhancing of Ca2+ uniporter, alleviated the adverse effects of NKA inhibition. Intriguingly, NKA inhibition elicited Ca2+ transient and action potential alternans under more stressed conditions such as severe ATP depletion, augmenting its proarrhythmic effect. This computational study provides new insights into the mechanisms underlying cardiac glycoside-induced arrhythmogenesis. The findings suggest that targeting both ion handling and mitochondria could be a very promising strategy to develop new glycoside-based therapies in the treatment of heart failure.
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Affiliation(s)
- Qince Li
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Comprehensive Cardiovascular Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Steven M. Pogwizd
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Comprehensive Cardiovascular Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Sumanth D. Prabhu
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Comprehensive Cardiovascular Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Lufang Zhou
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Comprehensive Cardiovascular Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- * E-mail:
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50
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Scorzeto M, Giacomello M, Toniolo L, Canato M, Blaauw B, Paolini C, Protasi F, Reggiani C, Stienen GJM. Mitochondrial Ca2+-handling in fast skeletal muscle fibers from wild type and calsequestrin-null mice. PLoS One 2013; 8:e74919. [PMID: 24098358 PMCID: PMC3789688 DOI: 10.1371/journal.pone.0074919] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 08/07/2013] [Indexed: 11/19/2022] Open
Abstract
Mitochondrial calcium handling and its relation with calcium released from sarcoplasmic reticulum (SR) in muscle tissue are subject of lively debate. In this study we aimed to clarify how the SR determines mitochondrial calcium handling using dCASQ-null mice which lack both isoforms of the major Ca2+-binding protein inside SR, calsequestrin. Mitochondrial free Ca2+-concentration ([Ca2+]mito) was determined by means of a genetically targeted ratiometric FRET-based probe. Electron microscopy revealed a highly significant increase in intermyofibrillar mitochondria (+55%) and augmented coupling (+12%) between Ca2+ release units of the SR and mitochondria in dCASQ-null vs. WT fibers. Significant differences in the baseline [Ca2+]mito were observed between quiescent WT and dCASQ-null fibers, but not in the resting cytosolic Ca2+ concentration. The rise in [Ca2+]mito during electrical stimulation occurred in 20−30 ms, while the decline during and after stimulation was governed by 4 rate constants of approximately 40, 1.6, 0.2 and 0.03 s−1. Accordingly, frequency-dependent increase in [Ca2+]mito occurred during sustained contractions. In dCASQ-null fibers the increases in [Ca2+]mito were less pronounced than in WT fibers and even lower when extracellular calcium was removed. The amplitude and duration of [Ca2+]mito transients were increased by inhibition of mitochondrial Na+/Ca2+ exchanger (mNCX). These results provide direct evidence for fast Ca2+ accumulation inside the mitochondria, involvement of the mNCX in mitochondrial Ca2+-handling and a dependence of mitochondrial Ca2+-handling on intracellular (SR) and external Ca2+ stores in fast skeletal muscle fibers. dCASQ-null mice represent a model for malignant hyperthermia. The differences in structure and in mitochondrial function observed relative to WT may represent compensatory mechanisms for the disease-related reduction of calcium storage capacity of the SR and/or SR Ca2+-leakage.
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Affiliation(s)
- Michele Scorzeto
- Department of Biomedical Sciences and Interuniversity Institute of Myology (IIM), University of Padova, Padua, Italy
| | | | - Luana Toniolo
- Department of Biomedical Sciences and Interuniversity Institute of Myology (IIM), University of Padova, Padua, Italy
| | - Marta Canato
- Department of Biomedical Sciences and Interuniversity Institute of Myology (IIM), University of Padova, Padua, Italy
| | - Bert Blaauw
- Department of Biomedical Sciences and Interuniversity Institute of Myology (IIM), University of Padova, Padua, Italy
- Venetian Institute of Molecular Medicine, Padua, Italy
| | - Cecilia Paolini
- Department of Neuroscience and Imaging (DNI) and Center for Research on Ageing (CeSI), and Interuniversity Institute of Myology (IIM), University G. d' Annunzio, Chieti, Italy
| | - Feliciano Protasi
- Department of Neuroscience and Imaging (DNI) and Center for Research on Ageing (CeSI), and Interuniversity Institute of Myology (IIM), University G. d' Annunzio, Chieti, Italy
| | - Carlo Reggiani
- Department of Biomedical Sciences and Interuniversity Institute of Myology (IIM), University of Padova, Padua, Italy
| | - Ger J. M. Stienen
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
- Department of Physics and Astronomy, VU University Amsterdam, Amsterdam, The Netherlands
- * E-mail:
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