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Filadi R, Greotti E. The yin and yang of mitochondrial Ca 2+ signaling in cell physiology and pathology. Cell Calcium 2020; 93:102321. [PMID: 33310302 DOI: 10.1016/j.ceca.2020.102321] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/16/2020] [Accepted: 11/16/2020] [Indexed: 12/26/2022]
Abstract
Mitochondria are autonomous and dynamic cellular organelles orchestrating a diverse range of cellular activities. Numerous cell-signaling pathways target these organelles and Ca2+ is one of the most significant. Mitochondria are able to rapidly and transiently take up Ca2+, thanks to the mitochondrial Ca2+ uniporter complex, as well as to extrude it through the Na+/Ca2+ and H+/Ca2+ exchangers. The transient accumulation of Ca2+ in the mitochondrial matrix impacts on mitochondrial functions and cell pathophysiology. Here we summarize the role of mitochondrial Ca2+ signaling in both physiological (yang) and pathological (yin) processes and the methods that can be used to investigate mitochondrial Ca2+ homeostasis. As an example of the pivotal role of mitochondria in pathology, we described the state of the art of mitochondrial Ca2+ alterations in different pathological conditions, with a special focus on Alzheimer's disease.
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Affiliation(s)
- Riccardo Filadi
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy; Department of Biomedical Sciences, University of Padua, 35131, Padua, Italy.
| | - Elisa Greotti
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy; Department of Biomedical Sciences, University of Padua, 35131, Padua, Italy.
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2
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Suzuki J, Kanemaru K, Iino M. Genetically Encoded Fluorescent Indicators for Organellar Calcium Imaging. Biophys J 2016; 111:1119-1131. [PMID: 27477268 DOI: 10.1016/j.bpj.2016.04.054] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/30/2016] [Accepted: 04/01/2016] [Indexed: 12/14/2022] Open
Abstract
Optical Ca(2+) indicators are powerful tools for investigating intracellular Ca(2+) signals in living cells. Although a variety of Ca(2+) indicators have been developed, deciphering the physiological functions and spatiotemporal dynamics of Ca(2+) in intracellular organelles remains challenging. Genetically encoded Ca(2+) indicators (GECIs) using fluorescent proteins are promising tools for organellar Ca(2+) imaging, and much effort has been devoted to their development. In this review, we first discuss the key points of organellar Ca(2+) imaging and summarize the requirements for optimal organellar Ca(2+) indicators. Then, we highlight some of the recent advances in the engineering of fluorescent GECIs targeted to specific organelles. Finally, we discuss the limitations of currently available GECIs and the requirements for advancing the research on intraorganellar Ca(2+) signaling.
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Affiliation(s)
- Junji Suzuki
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Department of Physiology, University of California San Francisco, San Francisco, California
| | - Kazunori Kanemaru
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Masamitsu Iino
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Department of Cellular and Molecular Pharmacology, Nihon University School of Medicine, Tokyo, Japan.
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3
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A comparison of fluorescent Ca²⁺ indicators for imaging local Ca²⁺ signals in cultured cells. Cell Calcium 2015; 58:638-48. [PMID: 26572560 DOI: 10.1016/j.ceca.2015.10.003] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 10/05/2015] [Accepted: 10/26/2015] [Indexed: 11/23/2022]
Abstract
Localized subcellular changes in Ca(2+) serve as important cellular signaling elements, regulating processes as diverse as neuronal excitability and gene expression. Studies of cellular Ca(2+) signaling have been greatly facilitated by the availability of fluorescent Ca(2+) indicators. The respective merits of different indicators to monitor bulk changes in cellular Ca(2+) levels have been widely evaluated, but a comprehensive comparison for their use in detecting and analyzing local, subcellular Ca(2+) signals is lacking. Here, we evaluated several fluorescent Ca(2+) indicators in the context of local Ca(2+) signals (puffs) evoked by inositol 1,4,5-trisphosphate (IP3) in cultured human neuroblastoma SH-SY5Y cells, using high-speed video-microscopy. Altogether, nine synthetic Ca(2+) dyes (Fluo-4, Fluo-8, Fluo-8 high affinity, Fluo-8 low affinity, Oregon Green BAPTA-1, Cal-520, Rhod-4, Asante Calcium Red, and X-Rhod-1) and three genetically-encoded Ca(2+)-indicators (GCaMP6-slow, -medium and -fast variants) were tested; criteria include the magnitude, kinetics, signal-to-noise ratio and detection efficiency of local Ca(2+) puffs. Among these, we conclude that Cal-520 is the optimal indicator for detecting and faithfully tracking local events; that Rhod-4 is the red-emitting indicator of choice; and that none of the GCaMP6 variants are well suited for imaging subcellular Ca(2+) signals.
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Zhao Z, Cui W, Zhang H, Gao H, Li X, Wang Y, Hu H, Li B. Pre-treatment of a single high-dose of atorvastatin provided cardioprotection in different ischaemia/reperfusion models via activating mitochondrial KATP channel. Eur J Pharmacol 2015; 751:89-98. [DOI: 10.1016/j.ejphar.2015.01.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 01/18/2015] [Accepted: 01/20/2015] [Indexed: 12/31/2022]
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5
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Kaestner L, Scholz A, Tian Q, Ruppenthal S, Tabellion W, Wiesen K, Katus HA, Müller OJ, Kotlikoff MI, Lipp P. Genetically encoded Ca2+ indicators in cardiac myocytes. Circ Res 2014; 114:1623-39. [PMID: 24812351 DOI: 10.1161/circresaha.114.303475] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Genetically encoded Ca(2+) indicators constitute a powerful set of tools to investigate functional aspects of Ca(2+) signaling in isolated cardiomyocytes, cardiac tissue, and whole hearts. Here, we provide an overview of the concepts, experiences, state of the art, and ongoing developments in the use of genetically encoded Ca(2+) indicators for cardiac cells and heart tissue. This review is supplemented with in vivo viral gene transfer experiments and comparisons of available genetically encoded Ca(2+) indicators with each other and with the small molecule dye Fura-2. In the context of cardiac myocytes, we provide guidelines for selecting a genetically encoded Ca(2+) indicator. For future developments, we discuss improvements of a broad range of properties, including photophysical properties such as spectral spread and biocompatibility, as well as cellular and in vivo applications.
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Affiliation(s)
- Lars Kaestner
- From the Institute for Molecular Cell Biology and Research Center for Molecular Imaging and Screening, School of Medicine, Saarland University, Homburg-Saar, Germany (L.K., A.S., Q.T., S.R., W.T., K.W., P.L.); Department of Internal Medicine III, University of Heidelberg, Heidelberg, Germany (H.A.K., O.J.M.); DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Germany (H.A.K., O.J.M.); and Biomedical Sciences Department, College of Veterinary Medicine, Cornell University, Ithaca, NY (M.I.K.)
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6
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Shintani Y, Drexler HCA, Kioka H, Terracciano CMN, Coppen SR, Imamura H, Akao M, Nakai J, Wheeler AP, Higo S, Nakayama H, Takashima S, Yashiro K, Suzuki K. Toll-like receptor 9 protects non-immune cells from stress by modulating mitochondrial ATP synthesis through the inhibition of SERCA2. EMBO Rep 2014; 15:438-45. [PMID: 24610369 PMCID: PMC3989675 DOI: 10.1002/embr.201337945] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 02/07/2014] [Accepted: 02/10/2014] [Indexed: 11/10/2022] Open
Abstract
Toll-like receptor 9 (TLR9) has a key role in the recognition of pathogen DNA in the context of infection and cellular DNA that is released from damaged cells. Pro-inflammatory TLR9 signalling pathways in immune cells have been well investigated, but we have recently discovered an alternative pathway in which TLR9 temporarily reduces energy substrates to induce cellular protection from stress in cardiomyocytes and neurons. However, the mechanism by which TLR9 stimulation reduces energy substrates remained unknown. Here, we identify the calcium-transporting ATPase, SERCA2 (also known as Atp2a2), as a key molecule for the alternative TLR9 signalling pathway. TLR9 stimulation reduces SERCA2 activity, modulating Ca(2+) handling between the SR/ER and mitochondria, which leads to a decrease in mitochondrial ATP levels and the activation of cellular protective machinery. These findings reveal how distinct innate responses can be elicited in immune and non-immune cells--including cardiomyocytes--using the same ligand-receptor system.
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Affiliation(s)
- Yasunori Shintani
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of LondonLondon, UK
- Department of Medical Biochemistry, Osaka University Graduate School of MedicineSuita, Japan
| | - Hannes CA Drexler
- Bioanalytical Mass Spectrometry, Max Planck Institute for Molecular BiomedicineMuenster, Germany
| | - Hidetaka Kioka
- Department of Cardiovascular Medicine, Osaka University Graduate School of MedicineSuita, Japan
| | - Cesare MN Terracciano
- Laboratory of Myocardial Electrophysiology, Imperial Centre for Translational and Experimental Medicine, Imperial College London, National Heart & Lung Institute, Hammersmith CampusLondon, UK
| | - Steven R Coppen
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of LondonLondon, UK
| | - Hiromi Imamura
- The Hakubi Center & Graduate School of Biostudies, Faculty of Medicine Campus, Kyoto University Science Frontier Laboratory building Room 305Kyoto, Japan
| | - Masaharu Akao
- Department of Cardiology, National Hospital Organization Kyoto Medical CenterKyoto, Japan
| | - Junichi Nakai
- Saitama University Brain Science InstituteSaitama City, Japan
| | - Ann P Wheeler
- Blizard Advanced Light Microscopy Facility, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of LondonLondon, UK
| | - Shuichiro Higo
- Department of Cardiovascular Medicine, Osaka University Graduate School of MedicineSuita, Japan
| | - Hiroyuki Nakayama
- Laboratory of Clinical Science and Biomedicine, Osaka University Graduate School of Pharmaceutical SciencesOsaka, Japan
| | - Seiji Takashima
- Department of Medical Biochemistry, Osaka University Graduate School of MedicineSuita, Japan
- Department of Cardiovascular Medicine, Osaka University Graduate School of MedicineSuita, Japan
| | - Kenta Yashiro
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of LondonLondon, UK
| | - Ken Suzuki
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of LondonLondon, UK
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7
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Hill JM, De Stefani D, Jones AWE, Ruiz A, Rizzuto R, Szabadkai G. Measuring baseline Ca(2+) levels in subcellular compartments using genetically engineered fluorescent indicators. Methods Enzymol 2014; 543:47-72. [PMID: 24924127 DOI: 10.1016/b978-0-12-801329-8.00003-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Intracellular Ca(2+) signaling is involved in a series of physiological and pathological processes. In particular, an intimate crosstalk between bioenergetic metabolism and Ca(2+) homeostasis has been shown to determine cell fate in resting conditions as well as in response to stress. The endoplasmic reticulum and mitochondria represent key hubs of cellular metabolism and Ca(2+) signaling. However, it has been challenging to specifically detect highly localized Ca(2+) fluxes such as those bridging these two organelles. To circumvent this issue, various recombinant Ca(2+) indicators that can be targeted to specific subcellular compartments have been developed over the past two decades. While the use of these probes for measuring agonist-induced Ca(2+) signals in various organelles has been extensively described, the assessment of basal Ca(2+) concentrations within specific organelles is often disregarded, in spite of the fact that this parameter is vital for several metabolic functions, including the enzymatic activity of mitochondrial dehydrogenases of the Krebs cycle and protein folding in the endoplasmic reticulum. Here, we provide an overview on genetically engineered, organelle-targeted fluorescent Ca(2+) probes and outline their evolution. Moreover, we describe recently developed protocols to quantify baseline Ca(2+) concentrations in specific subcellular compartments. Among several applications, this method is suitable for assessing how changes in basal Ca(2+) levels affect the metabolic profile of cancer cells.
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Affiliation(s)
- Julia M Hill
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, London, United Kingdom
| | - Diego De Stefani
- Department of Biomedical Sciences, CNR Neuroscience Institute, University of Padua, Padua, Italy
| | - Aleck W E Jones
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, London, United Kingdom
| | - Asier Ruiz
- Department of Neurosciences, University of the Basque Country (UPV/EHU), Achúcarro Basque Center for Neuroscience-UPV/EHU, Leioa, Spain; Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, (CIBERNED), Madrid, Spain
| | - Rosario Rizzuto
- Department of Biomedical Sciences, CNR Neuroscience Institute, University of Padua, Padua, Italy
| | - Gyorgy Szabadkai
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, London, United Kingdom; Department of Biomedical Sciences, CNR Neuroscience Institute, University of Padua, Padua, Italy.
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8
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Mohamed TMA, Abou-Leisa R, Baudoin F, Stafford N, Neyses L, Cartwright EJ, Oceandy D. Development and characterization of a novel fluorescent indicator protein PMCA4-GCaMP2 in cardiomyocytes. J Mol Cell Cardiol 2013; 63:57-68. [PMID: 23880607 DOI: 10.1016/j.yjmcc.2013.07.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 07/04/2013] [Accepted: 07/11/2013] [Indexed: 11/25/2022]
Abstract
Isoform 4 of the plasma membrane calcium/calmodulin dependent ATPase (PMCA4) has recently emerged as an important regulator of several key pathophysiological processes in the heart, such as contractility and hypertrophy. However, direct monitoring of PMCA4 activity and assessment of calcium dynamics in its vicinity in cardiomyocytes are difficult due to the lack of molecular tools. In this study, we developed novel calcium fluorescent indicators by fusing the GCaMP2 calcium sensor to the N-terminus of PMCA4 to generate the PMCA4-GCaMP2 fusion molecule. We also identified a novel specific inhibitor of PMCA4, which might be useful for studying the role of this molecule in cardiomyocytes and other cell types. Using an adenoviral system we successfully expressed PMCA4-GCaMP2 in both neonatal and adult rat cardiomyocytes. This fusion molecule was correctly targeted to the plasma membrane and co-localised with caveolin-3. It could monitor signal oscillations in electrically stimulated cardiomyocytes. The PMCA4-GCaMP2 generated a higher signal amplitude and faster signal decay rate compared to a mutant inactive PMCA4(mut)GCaMP2 fusion protein, in electrically stimulated neonatal and adult rat cardiomyocytes. A small molecule library screen enabled us to identify a novel selective inhibitor for PMCA4, which we found to reduce signal amplitude of PMCA4-GCaMP2 and prolong the time of signal decay (Tau) to a level comparable with the signal generated by PMCA4(mut)GCaMP2. In addition, PMCA4-GCaMP2 but not the mutant form produced an enhanced signal in response to β-adrenergic stimulation. Together, the PMCA4-GCaMP2 and PMCA4(mut)GCaMP2 demonstrate calcium dynamics in the vicinity of the pump under active or inactive conditions, respectively. In summary, the PMCA4-GCaMP2 together with the novel specific inhibitor provides new means with which to monitor calcium dynamics in the vicinity of a calcium transporter in cardiomyocytes and may become a useful tool to further study the biological functions of PMCA4. In addition, similar approaches could be useful for studying the activity of other calcium transporters during excitation-contraction coupling in the heart.
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Affiliation(s)
- Tamer M A Mohamed
- Institute of Cardiovascular Sciences, University of Manchester, Manchester Academic Health Sciences Centre, Manchester M13 9PT, UK; Department of Biochemistry, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
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Probing neuronal activities with genetically encoded optical indicators: from a historical to a forward-looking perspective. Pflugers Arch 2012; 465:361-71. [PMID: 23271451 DOI: 10.1007/s00424-012-1202-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 12/06/2012] [Indexed: 10/27/2022]
Abstract
Optical imaging has a long history in physiology and in neurophysiology in particular. Over the past 15 years or so, new methodologies have emerged that combine genetic engineering with light-based imaging methods. This merger has resulted in a tool box of genetically encoded optical indicators that enable nondestructive and long-lasting monitoring of neuronal activities at the cellular, circuit, and system level. This review describes the historical roots and fundamental concepts underlying these new approaches, evaluates current progress in this field, and concludes with a forward-looking perspective on current work and potential future developments in this field.
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Chen M, Wang Y, Hou T, Zhang H, Qu A, Wang X. Differential mitochondrial calcium responses in different cell types detected with a mitochondrial calcium fluorescent indicator, mito-GCaMP2. Acta Biochim Biophys Sin (Shanghai) 2011; 43:822-30. [PMID: 21880604 DOI: 10.1093/abbs/gmr075] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mitochondrial calcium plays a crucial role in mitochondrial metabolism, cell calcium handling, and cell death. However, some mechanisms concerning mitochondrial calcium regulation are still unknown, especially how mitochondrial calcium couples with cytosolic calcium. In this work, we constructed a novel mitochondrial calcium fluorescent indicator (mito-GCaMP2) by genetic manipulation. Mito-GCaMP2 was imported into mitochondria with high efficiency and the fluorescent signals co-localized with that of tetramethyl rhodamine methyl ester, a mitochondrial membrane potential indicator. The mitochondrial inhibitors specifically decreased the signals of mito-GCaMP2. The apparent K(d) of mito-GCaMP2 was 195.0 nmol/L at pH 8.0 in adult rat cardiomyocytes. Furthermore, we observed that mito-GCaMP2 preferred the alkaline pH surrounding of mitochondria. In HeLa cells, we found that mitochondrial calcium ([Ca(2+)](mito)) responded to the changes of cytosolic calcium ([Ca(2+)](cyto)) induced by histamine or thapasigargin. Moreover, external Ca(2+) (100 μmol/L) directly induced an increase of [Ca(2+)](mito) in permeabilized HeLa cells. However, in rat cardiomyocytes [Ca(2+)](mito) did not respond to cytosolic calcium transients stimulated by electric pacing or caffeine. In permeabilized cardiomyocytes, 600 nmol/L free Ca(2+) repeatedly increased the fluorescent signals of mito-GCaMP2, which excluded the possibility that mito-GCaMP2 lost its function in cardiomyocytes mitochondria. These results showed that the response of mitochondrial calcium is diverse in different cell lineages and suggested that mitochondria in cardiomyocytes may have a special defense mechanism to control calcium flux.
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Affiliation(s)
- Min Chen
- Yunnan Center for Disease Prevention and Control, Kunming, China.
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Dedkova EN, Blatter LA. Measuring mitochondrial function in intact cardiac myocytes. J Mol Cell Cardiol 2011; 52:48-61. [PMID: 21964191 DOI: 10.1016/j.yjmcc.2011.08.030] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 07/30/2011] [Accepted: 08/09/2011] [Indexed: 12/01/2022]
Abstract
Mitochondria are involved in cellular functions that go beyond the traditional role of these organelles as the power plants of the cell. Mitochondria have been implicated in several human diseases, including cardiac dysfunction, and play a role in the aging process. Many aspects of our knowledge of mitochondria stem from studies performed on the isolated organelle. Their relative inaccessibility imposes experimental difficulties to study mitochondria in their natural environment-the cytosol of intact cells-and has hampered a comprehensive understanding of the plethora of mitochondrial functions. Here we review currently available methods to study mitochondrial function in intact cardiomyocytes. These methods primarily use different flavors of fluorescent dyes and genetically encoded fluorescent proteins in conjunction with high-resolution imaging techniques. We review methods to study mitochondrial morphology, mitochondrial membrane potential, Ca(2+) and Na(+) signaling, mitochondrial pH regulation, redox state and ROS production, NO signaling, oxygen consumption, ATP generation and the activity of the mitochondrial permeability transition pore. Where appropriate we complement this review on intact myocytes with seminal studies that were performed on isolated mitochondria, permeabilized cells, and in whole hearts.
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Affiliation(s)
- Elena N Dedkova
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, IL 60612, USA
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