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Kurz FT, Aon MA, Schlemmer HP, Jende JME, O'Rourke B, Armoundas AA. Fractal dynamics of individual mitochondrial oscillators measure local inter-mitochondrial coupling. Biophys J 2023; 122:1459-1469. [PMID: 36905121 PMCID: PMC10147834 DOI: 10.1016/j.bpj.2023.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 09/29/2022] [Accepted: 03/06/2023] [Indexed: 03/11/2023] Open
Abstract
Mitochondrial inner membrane potentials in cardiomyocytes may oscillate in cycles of depolarization/repolarization when the mitochondrial network is exposed to metabolic or oxidative stress. The frequencies of such oscillations are dynamically changing while clusters of weakly coupled mitochondrial oscillators adjust to a common phase and frequency. Across the cardiac myocyte, the averaged signal of the mitochondrial population follows self-similar or fractal dynamics; however, fractal properties of individual mitochondrial oscillators have not yet been examined. We show that the largest synchronously oscillating cluster exhibits a fractal dimension, D, that is indicative of self-similar behavior with D=1.27±0.11, in contrast to the remaining network mitochondria whose fractal dimension is close to that of Brownian noise, D=1.58±0.10. We further demonstrate that fractal behavior is correlated with local coupling mechanisms, whereas it is only weakly linked to measures of functional connections between mitochondria. Our findings suggest that individual mitochondrial fractal dimensions may serve as a simple measure of local mitochondrial coupling.
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Affiliation(s)
- Felix T Kurz
- German Cancer Research Center, Division of Radiology, Heidelberg, Germany; Massachusetts General Hospital, Cardiovascular Research Center, Harvard Medical School, Charlestown, Massachusetts.
| | - Miguel A Aon
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | | | - Johann M E Jende
- Heidelberg University Hospital, Department of Neuroradiology, Heidelberg, Germany
| | - Brian O'Rourke
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, Maryland
| | - Antonis A Armoundas
- Massachusetts General Hospital, Cardiovascular Research Center, Harvard Medical School, Charlestown, Massachusetts; Broad Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts.
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2
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Chakraborty P, Farhat K, Po SS, Armoundas AA, Stavrakis S. Autonomic Nervous System and Cardiac Metabolism: Links Between Autonomic and Metabolic Remodeling in Atrial Fibrillation. JACC Clin Electrophysiol 2023:S2405-500X(23)00117-2. [PMID: 37086229 DOI: 10.1016/j.jacep.2023.02.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/27/2023] [Accepted: 02/16/2023] [Indexed: 04/23/2023]
Abstract
Simultaneous activation of the sympathetic and parasympathetic nervous systems is crucial for the initiation of paroxysmal atrial fibrillation (AF). However, unbalanced activation of the sympathetic system is characteristic of autonomic remodeling in long-standing persistent AF. Moreover, the adrenergic activation-induced metabolic derangements provide a milieu for acute AF and promote the transition from the paroxysmal to the persistent phase of AF. On the other hand, cholinergic activation ameliorates the maladaptive metabolic remodeling in the face of metabolic challenges. Selective inhibition of the sympathetic system and restoration of the balance of the cholinergic system by neuromodulation is emerging as a novel nonpharmacologic strategy for managing AF. This review explores the link between cardiac autonomic and metabolic remodeling and the potential roles of different autonomic modulation strategies on atrial metabolic aberrations in AF.
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Affiliation(s)
- Praloy Chakraborty
- Cardiovascular Section, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Kassem Farhat
- Cardiovascular Section, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Sunny S Po
- Cardiovascular Section, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts, USA; Broad Institute, Massachusetts Institute of Technology, Boston, Massachusetts, USA
| | - Stavros Stavrakis
- Cardiovascular Section, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
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3
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Urbisz AZ, Chajec Ł, Małota K, Student S, Sawadro MK, Śliwińska MA, Świątek P. All for one - changes in mitochondrial morphology and activity during syncytial oogenesis. Biol Reprod 2022; 106:1232-1253. [PMID: 35156116 DOI: 10.1093/biolre/ioac035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 12/23/2021] [Accepted: 02/10/2022] [Indexed: 11/14/2022] Open
Abstract
The syncytial groups of germ cells (germ-line cysts) forming in ovaries of clitellate annelids are an attractive model to study mitochondrial stage-specific changes. Using transmission electron microscopy, serial block-face scanning electron microscopy, and fluorescent microscopy, we analyzed the mitochondria distribution and morphology and the state of membrane potential in female cysts in Enchytraeus albidus. We visualized in 3D at the ultrastructural level mitochondria in cysts at successive stages: 2-celled, 4-celled, 16-celled cysts, and cyst in advanced oogenesis. We found that mitochondria form extensive aggregates - they are fused and connected into large and branched mitochondrial networks. The most extensive networks are formed with up to 10,000 fused mitochondria, whereas individual organelles represent up to 2% of the total mitochondrial volume. We classify such morphology of mitochondria as a dynamic hyperfusion state, and suggest that it can maintain their high activity and intensifies the process of cellular respiration within the syncytial cysts. We found some individual mitochondria undergoing degradation, which implies that damaged mitochondria are removed from networks for their final elimination. As it was shown that growing oocytes possess less active mitochondria than the nurse cells, it suggests that the high activity of mitochondria in the nurse cells and their dynamic hyperfusion state serve the needs of the growing oocyte. Additionally, we measured by calorimetry the total antioxidant capacity of germ-line cysts in comparison to somatic tissue, and it suggests that antioxidative defense systems, together with mitochondrial networks, can effectively protect germ-line mitochondria from damage.
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Affiliation(s)
- Anna Z Urbisz
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland
| | - Łukasz Chajec
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland
| | - Karol Małota
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland
| | - Sebastian Student
- Institute of Automatic Control, Silesian University of Technology, Gliwice, Poland
| | - Marta K Sawadro
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland
| | - Małgorzata A Śliwińska
- Nencki Institute of Experimental Biology of Polish Academy of Sciences, Laboratory of Imaging Tissue Structure and Function, Warsaw, Poland
| | - Piotr Świątek
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland
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4
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Kurz FT, Breckwoldt MO. Automated Quantification and Network Analysis of Redox Dynamics in Neuronal Mitochondria. Methods Mol Biol 2022; 2399:261-274. [PMID: 35604561 DOI: 10.1007/978-1-0716-1831-8_12] [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] [Indexed: 06/15/2023]
Abstract
Mitochondria are complex organelles with multifaceted roles in cell biology, acting as signaling hubs that implicate them in cellular physiology and pathology. Mitochondria are both the target and the origin of multiple signaling events, including redox processes and calcium signaling which are important for organellar function and homeostasis. One way to interrogate mitochondrial function is by live cell imaging. Elaborated approaches perform imaging of single mitochondrial dynamics in living cells and animals. Imaging mitochondrial signaling and function can be challenging due to the sheer number of mitochondria, and the speed, propagation, and potential short half-life of signals. Moreover, mitochondria are organized in functionally coupled interorganellar networks. Therefore, advanced analysis and postprocessing tools are needed to enable automated analysis to fully quantitate mitochondrial signaling events and decipher their complex spatiotemporal connectedness. Herein, we present a protocol for recording and automating analyses of signaling in neuronal mitochondrial networks.
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Affiliation(s)
- Felix T Kurz
- Heidelberg University Hospital, Department of Neuroradiology, Heidelberg, Germany.
- German Cancer Research Center, Department of Radiology, Heidelberg, Germany.
| | - Michael O Breckwoldt
- Heidelberg University Hospital, Department of Neuroradiology, Heidelberg, Germany.
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5
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MitoWave: Spatiotemporal analysis of mitochondrial membrane potential fluctuations during I/R. Biophys J 2021; 120:3261-3271. [PMID: 34297964 DOI: 10.1016/j.bpj.2021.05.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 03/26/2021] [Accepted: 05/06/2021] [Indexed: 11/21/2022] Open
Abstract
Mitochondria exhibit unstable inner membrane potentials (ΔΨm) when subjected to stress, such as during ischemia/reperfusion (I/R). Understanding the mechanism of ΔΨm instability involves characterizing and quantifying this phenomenon in an unbiased and reproducible manner. Here, we describe a simple analytical workflow called "MitoWave" that combines wavelet transform methods and image segmentation to unravel dynamic ΔΨm changes in the cardiac mitochondrial network during I/R. In vitro ischemia was affected by placing a glass coverslip on a monolayer of neonatal mouse ventricular myocytes for 1 h and removing the coverslip to allow for reperfusion, revealing complex oscillatory ΔΨm. MitoWave analysis was then used to identify individual mitochondrial clusters within the cells and track their intrinsic oscillation frequencies over the course of reperfusion. Responses segregated into five typical behaviors were quantified by MitoWave that were corroborated by visual inspection of the time series. Statistical analysis of the distribution of oscillating mitochondrial clusters during reperfusion showed significant differences between the five different outcomes. Features such as the time point of ΔΨm depolarization during I/R, area of mitochondrial clusters, and time-resolved frequency components during reperfusion were determined per cell and per mitochondrial cluster. Mitochondria from neonatal mouse ventricular myocytes subjected to I/R oscillate in the frequency range of 8.6-45 mHz, with a mean of 8.73 ± 4.35 mHz. Oscillating clusters had smaller areas ranging from 49.8 ± 1.2 μm2, whereas nonoscillating clusters had larger areas 66 ± 1.5 μm2. A negative correlation between frequency and mitochondrial cluster area was observed. We also observed that late ΔΨm loss during ischemia correlated with early ΔΨm stabilization after oscillation on reperfusion. Thus, MitoWave analysis provides a semiautomated method to quantify complex time-resolved mitochondrial behavior in an easy-to-follow workflow, enabling unbiased, reproducible quantitation of complex nonstationary cellular phenomena.
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6
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Zhang Q, Gheres KW, Drew PJ. Origins of 1/f-like tissue oxygenation fluctuations in the murine cortex. PLoS Biol 2021; 19:e3001298. [PMID: 34264930 PMCID: PMC8282088 DOI: 10.1371/journal.pbio.3001298] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 05/24/2021] [Indexed: 01/07/2023] Open
Abstract
The concentration of oxygen in the brain spontaneously fluctuates, and the distribution of power in these fluctuations has a 1/f-like spectra, where the power present at low frequencies of the power spectrum is orders of magnitude higher than at higher frequencies. Though these oscillations have been interpreted as being driven by neural activity, the origin of these 1/f-like oscillations is not well understood. Here, to gain insight of the origin of the 1/f-like oxygen fluctuations, we investigated the dynamics of tissue oxygenation and neural activity in awake behaving mice. We found that oxygen signal recorded from the cortex of mice had 1/f-like spectra. However, band-limited power in the local field potential did not show corresponding 1/f-like fluctuations. When local neural activity was suppressed, the 1/f-like fluctuations in oxygen concentration persisted. Two-photon measurements of erythrocyte spacing fluctuations and mathematical modeling show that stochastic fluctuations in erythrocyte flow could underlie 1/f-like dynamics in oxygenation. These results suggest that the discrete nature of erythrocytes and their irregular flow, rather than fluctuations in neural activity, could drive 1/f-like fluctuations in tissue oxygenation.
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Affiliation(s)
- Qingguang Zhang
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail: (QZ); (PJD)
| | - Kyle W. Gheres
- Graduate Program in Molecular Cellular and Integrative Biosciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Patrick J. Drew
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Neurosurgery, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail: (QZ); (PJD)
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7
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Seidlmayer LK, Hanson BJ, Thai PN, Schaefer S, Bers DM, Dedkova EN. PK11195 Protects From Cell Death Only When Applied During Reperfusion: Succinate-Mediated Mechanism of Action. Front Physiol 2021; 12:628508. [PMID: 34149440 PMCID: PMC8212865 DOI: 10.3389/fphys.2021.628508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 04/28/2021] [Indexed: 11/13/2022] Open
Abstract
Aim: Reperfusion after myocardial ischemia causes cellular injury, in part due to changes in mitochondrial Ca2+ handling, oxidative stress, and myocyte energetics. We have previously shown that the 18-kDa translocator protein of the outer mitochondrial membrane (TSPO) can modulate Ca2+ handling. Here, we aim to evaluate the role of the TSPO in ischemia/reperfusion (I/R) injury. Methods: Rabbit ventricular myocytes underwent simulated acute ischemia (20 min) and reperfusion (at 15 min, 1 h, and 3 h) in the absence and presence of 50 μM PK11195, a TSPO inhibitor. Cell death was measured by lactate dehydrogenase (LDH) assay, while changes in mitochondrial Ca2+, membrane potential (ΔΨm), and reactive oxygen species (ROS) generation were monitored using confocal microscopy in combination with fluorescent indicators. Substrate utilization was measured with Biolog mitochondrial plates. Results: Cell death was increased by ~200% following I/R compared to control untreated ventricular myocytes. Incubation with 50 μM PK11195 during both ischemia and reperfusion did not reduce cell death but increased mitochondrial Ca2+ uptake and ROS generation. However, application of 50 μM PK11195 only at the onset and during reperfusion effectively protected against cell death. The large-scale oscillations in ΔΨm observed after ~1 h of reperfusion were significantly delayed by 1 μM cyclosporin A and almost completely prevented by 50 μM PK11195 applied during 3 h of reperfusion. After an initial increase, mitochondrial Ca2+, measured with Myticam, rapidly declined during 3 h of reperfusion after the initial transient increase. This decline was prevented by application of PK11195 at the onset and during reperfusion. PK11195 prevented a significant increase in succinate utilization following I/R and succinate-induced forward-mode ROS generation. Treatment with PK11195 was also associated with a significant increase in glutamate and a decrease in leucine utilization. Conclusion: PK11195 administered specifically at the moment of reperfusion limited ROS-induced ROS release and cell death, likely in part, by a shift from succinate to glutamate utilization. These data demonstrate a unique mechanism to limit cardiac injury after I/R.
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Affiliation(s)
- Lea K Seidlmayer
- Department of Cardiology, University Hospital Olbenburg, Olbenburg, Germany
| | - Benjamin J Hanson
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Phung N Thai
- Department of Internal Medicine, Division of Cardiovascular Medicine, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Saul Schaefer
- Department of Internal Medicine, Division of Cardiovascular Medicine, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Donald M Bers
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Elena N Dedkova
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
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8
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Rogov AG, Goleva TN, Epremyan KK, Kireev II, Zvyagilskaya RA. Propagation of Mitochondria-Derived Reactive Oxygen Species within the Dipodascus magnusii Cells. Antioxidants (Basel) 2021; 10:antiox10010120. [PMID: 33467672 PMCID: PMC7830518 DOI: 10.3390/antiox10010120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 12/04/2022] Open
Abstract
Mitochondria are considered to be the main source of reactive oxygen species (ROS) in the cell. It was shown that in cardiac myocytes exposed to excessive oxidative stress, ROS-induced ROS release is triggered. However, cardiac myocytes have a network of densely packed organelles that do not move, which is not typical for the majority of eukaryotic cells. The purpose of this study was to trace the spatiotemporal development (propagation) of prooxidant-induced oxidative stress and its interplay with mitochondrial dynamics. We used Dipodascus magnusii yeast cells as a model, as they have advantages over other models, including a uniquely large size, mitochondria that are easy to visualize and freely moving, an ability to vigorously grow on well-defined low-cost substrates, and high responsibility. It was shown that prooxidant-induced oxidative stress was initiated in mitochondria, far preceding the appearance of generalized oxidative stress in the whole cell. For yeasts, these findings were obtained for the first time. Preincubation of yeast cells with SkQ1, a mitochondria-addressed antioxidant, substantially diminished production of mitochondrial ROS, while only slightly alleviating the generalized oxidative stress. This was expected, but had not yet been shown. Importantly, mitochondrial fragmentation was found to be primarily induced by mitochondrial ROS preceding the generalized oxidative stress development.
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Affiliation(s)
- Anton G. Rogov
- Bach Institute of Biochemistry, Federal Research Center “Fundamentals of Biotechnology” of the Russian Academy of Sciences 33, bld. 2 Leninsky Ave., Moscow 119071, Russia; (A.G.R.); (T.N.G.); (K.K.E.)
| | - Tatiana N. Goleva
- Bach Institute of Biochemistry, Federal Research Center “Fundamentals of Biotechnology” of the Russian Academy of Sciences 33, bld. 2 Leninsky Ave., Moscow 119071, Russia; (A.G.R.); (T.N.G.); (K.K.E.)
| | - Khoren K. Epremyan
- Bach Institute of Biochemistry, Federal Research Center “Fundamentals of Biotechnology” of the Russian Academy of Sciences 33, bld. 2 Leninsky Ave., Moscow 119071, Russia; (A.G.R.); (T.N.G.); (K.K.E.)
| | - Igor I. Kireev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Vorobyevy Gory 1, Moscow 119992, Russia;
| | - Renata A. Zvyagilskaya
- Bach Institute of Biochemistry, Federal Research Center “Fundamentals of Biotechnology” of the Russian Academy of Sciences 33, bld. 2 Leninsky Ave., Moscow 119071, Russia; (A.G.R.); (T.N.G.); (K.K.E.)
- Correspondence:
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9
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Hydrogen peroxide diffusion and scavenging shapes mitochondrial network instability and failure by sensitizing ROS-induced ROS release. Sci Rep 2020; 10:15758. [PMID: 32978406 PMCID: PMC7519669 DOI: 10.1038/s41598-020-71308-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 08/11/2020] [Indexed: 02/07/2023] Open
Abstract
The mitochondrial network of cardiac cells is finely tuned for ATP delivery to sites of energy demand; however, emergent phenomena, such as mitochondrial transmembrane potential oscillations or propagating waves of depolarization have been observed under metabolic stress. While regenerative signaling by reactive oxygen species (ROS)-induced ROS release (RIRR) has been suggested as a potential trigger, it is unknown how it could lead to widespread responses. Here, we present a novel computational model of RIRR transmission that explains the mechanisms of this phenomenon. The results reveal that superoxide mediates neighbor-neighbor activation of energy-dissipating ion channels, while hydrogen peroxide distributes oxidative stress to sensitize the network to mitochondrial criticality. The findings demonstrate the feasibility of RIRR as a synchronizing factor across the dimensions of the adult heart cell and illustrate how a cascade of failures at the organellar level can scale to impact cell and organ level functions of the heart.
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10
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Van Wijk R, Van Wijk EP, Pang J, Yang M, Yan Y, Han J. Integrating Ultra-Weak Photon Emission Analysis in Mitochondrial Research. Front Physiol 2020; 11:717. [PMID: 32733265 PMCID: PMC7360823 DOI: 10.3389/fphys.2020.00717] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/29/2020] [Indexed: 12/11/2022] Open
Abstract
Once regarded solely as the energy source of the cell, nowadays mitochondria are recognized to perform multiple essential functions in addition to energy production. Since the discovery of pathogenic mitochondrial DNA defects in the 1980s, research advances have revealed an increasing number of common human diseases, which share an underlying pathogenesis involving mitochondrial dysfunction. A major factor in this dysfunction is reactive oxygen species (ROS), which influence the mitochondrial-nuclear crosstalk and the link with the epigenome, an influence that provides explanations for pathogenic mechanisms. Regarding these mechanisms, we should take into account that mitochondria produce the majority of ultra-weak photon emission (UPE), an aspect that is often ignored - this type of emission may serve as assay for ROS, thus providing new opportunities for a non-invasive diagnosis of mitochondrial dysfunction. In this article, we overviewed three relevant areas of mitochondria-related research over the period 1960-2020: (a) respiration and energy production, (b) respiration-related production of free radicals and other ROS species, and (c) ultra-weak photon emission in relation to ROS and stress. First, we have outlined how these research areas initially developed independently of each other - following that, our review aims to show their stepwise integration during later stages of development. It is suggested that a further stimulation of research on UPE may have the potential to enhance the progress of modern mitochondrial research and its integration in medicine.
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Affiliation(s)
- Roeland Van Wijk
- Meluna Research, Department of Biophotonics, Geldermalsen, Netherlands
| | | | - Jingxiang Pang
- Key Laboratory for Biotech-Drugs of National Health Commission, Shandong Medicinal Biotechnology Center, Jinan, China
- Shandong First Medical University, Jinan, China
- Shandong Academy of Medical Sciences, Jinan, China
| | - Meina Yang
- Key Laboratory for Biotech-Drugs of National Health Commission, Shandong Medicinal Biotechnology Center, Jinan, China
- Shandong First Medical University, Jinan, China
- Shandong Academy of Medical Sciences, Jinan, China
| | - Yu Yan
- Meluna Research, Department of Biophotonics, Geldermalsen, Netherlands
| | - Jinxiang Han
- Key Laboratory for Biotech-Drugs of National Health Commission, Shandong Medicinal Biotechnology Center, Jinan, China
- Shandong First Medical University, Jinan, China
- Shandong Academy of Medical Sciences, Jinan, China
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11
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Morphology of Mitochondria in Syncytial Annelid Female Germ-Line Cyst Visualized by Serial Block-Face SEM. Int J Cell Biol 2020; 2020:7483467. [PMID: 32395131 PMCID: PMC7199535 DOI: 10.1155/2020/7483467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 07/11/2019] [Accepted: 08/04/2019] [Indexed: 11/23/2022] Open
Abstract
Mitochondria change their morphology and distribution depending on the metabolism and functional state of a cell. Here, we analyzed the mitochondria and selected structures in female germ-line cysts in a representative of clitellate annelids – the white worm Enchytraeus albidus in which each germ cell has one cytoplasmic bridge that connects it to a common cytoplasmic mass. Using serial block-face scanning electron microscopy (SBEM), we prepared three-dimensional ultrastructural reconstructions of the entire selected compartments of a cyst at the advanced stage of oogenesis, i.e. the nurse cell, cytophore, and cytoplasmic bridges of all 16 cells (15 nurse cells and oocyte). We revealed extensive mitochondrial networks in the nurse cells, cytophore and mitochondria that pass through the cytoplasmic bridges, which indicates that a mitochondrial network can extend throughout the entire cyst. The dynamic hyperfusion state was suggested for such mitochondrial aggregations. We measured the mitochondria distribution and revealed their polarized distribution in the nurse cells and more abundant accumulation within the cytophore compared to the nurse cell. A close association of mitochondrial networks with dispersed nuage material, which seems to be the structural equivalent of a Balbiani body, not described in clitellate annelids so far, was also revealed.
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12
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Vetter L, Cortassa S, O'Rourke B, Armoundas AA, Bedja D, Jende JME, Bendszus M, Paolocci N, Sollot SJ, Aon MA, Kurz FT. Diabetes Increases the Vulnerability of the Cardiac Mitochondrial Network to Criticality. Front Physiol 2020; 11:175. [PMID: 32210835 PMCID: PMC7077512 DOI: 10.3389/fphys.2020.00175] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 02/14/2020] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial criticality describes a state in which the mitochondrial cardiac network under intense oxidative stress becomes very sensitive to small perturbations, leading from local to cell-wide depolarization and synchronized oscillations that may escalate to the myocardial syncytium generating arrhythmias. Herein, we describe the occurrence of mitochondrial criticality in the chronic setting of a metabolic disorder, type 1 diabetes (T1DM), using a streptozotocin (STZ)-treated guinea pig (GP) animal model. Using wavelet analysis of mitochondrial networks from two-photon microscopy imaging of cardiac myocytes loaded with a fluorescent probe of the mitochondrial membrane potential, we show that cardiomyocytes from T1DM GPs are closer to criticality, making them more vulnerable to cell-wide mitochondrial oscillations as can be judged by the latency period to trigger oscillations after a laser flash perturbation, and their propensity to oscillate. Insulin treatment of T1DM GPs rescued cardiac myocytes to sham control levels of susceptibility, a protective condition that could also be attained with interventions leading to improvement of the cellular redox environment such as preincubation of diabetic cardiac myocytes with the lipid palmitate or a cell-permeable form of glutathione, in the presence of glucose.
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Affiliation(s)
- Larissa Vetter
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States.,Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Sonia Cortassa
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Brian O'Rourke
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology Cambridge, MA, United States
| | - Djahida Bedja
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Johann M E Jende
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Martin Bendszus
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Nazareno Paolocci
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD, United States.,Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Steven J Sollot
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Miguel A Aon
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Felix T Kurz
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.,Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States
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13
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Torres MJ, McLaughlin KL, Renegar RH, Valsaraj S, Whitehurst KS, Sharaf OM, Sharma UM, Horton JL, Sarathy B, Parks JC, Brault JJ, Fisher-Wellman KH, Neufer PD, Virag JAI. Intracardiac administration of ephrinA1-Fc preserves mitochondrial bioenergetics during acute ischemia/reperfusion injury. Life Sci 2019; 239:117053. [PMID: 31733316 DOI: 10.1016/j.lfs.2019.117053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/06/2019] [Accepted: 11/08/2019] [Indexed: 12/18/2022]
Abstract
AIMS Intracardiac injection of recombinant EphrinA1-Fc immediately following coronary artery ligation in mice reduces infarct size in both reperfused and non-reperfused myocardium, but the cellular alterations behind this phenomenon remain unknown. MAIN METHODS Herein, 10 wk-old B6129SF2/J male mice were exposed to acute ischemia/reperfusion (30minI/24hrsR) injury immediately followed by intracardiac injection of either EphrinA1-Fc or IgG-Fc. After 24 h of reperfusion, sections of the infarct margin in the left ventricle were imaged via transmission electron microscopy, and mitochondrial function was assessed in both permeabilized fibers and isolated mitochondria, to examine mitochondrial structure, function, and energetics in the early stages of repair. KEY FINDINGS At a structural level, EphrinA1-Fc administration prevented the I/R-induced loss of sarcomere alignment and mitochondrial organization along the Z disks, as well as disorganization of the cristae and loss of inter-mitochondrial junctions. With respect to bioenergetics, loss of respiratory function induced by I/R was prevented by EphrinA1-Fc. Preservation of cardiac bioenergetics was not due to changes in mitochondrial JH2O2 emitting potential, membrane potential, ADP affinity, efficiency of ATP production, or activity of the main dehydrogenase enzymes, suggesting that EphrinA1-Fc indirectly maintains respiratory function via preservation of the mitochondrial network. Moreover, these protective effects were lost in isolated mitochondria, further emphasizing the importance of the intact cardiomyocyte ultrastructure in mitochondrial energetics. SIGNIFICANCE Collectively, these data suggest that intracardiac injection of EphrinA1-Fc protects cardiac function by preserving cardiomyocyte structure and mitochondrial bioenergetics, thus emerging as a potential therapeutic strategy in I/R injury.
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Affiliation(s)
- Maria J Torres
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, 27834, USA
| | - Kelsey L McLaughlin
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, 27834, USA; Dept of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Randall H Renegar
- Dept of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Smrithi Valsaraj
- Dept of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - K'Shylah S Whitehurst
- Dept of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Omar M Sharaf
- Dept of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Uma M Sharma
- Dept of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Julie L Horton
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, 27834, USA; Dept of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Brinda Sarathy
- Dept of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Justin C Parks
- Dept of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Jeffrey J Brault
- Dept of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA; Dept of Kinesiology, College of Health and Human Performance, East Carolina University, Greenville, NC, 27834, USA
| | - Kelsey H Fisher-Wellman
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, 27834, USA; Dept of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - P Darrell Neufer
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, 27834, USA; Dept of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Jitka A I Virag
- Dept of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA.
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14
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Arata Y, Takagi H. Quantitative Studies for Cell-Division Cycle Control. Front Physiol 2019; 10:1022. [PMID: 31496950 PMCID: PMC6713215 DOI: 10.3389/fphys.2019.01022] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/24/2019] [Indexed: 11/13/2022] Open
Abstract
The cell-division cycle (CDC) is driven by cyclin-dependent kinases (CDKs). Mathematical models based on molecular networks, as revealed by molecular and genetic studies, have reproduced the oscillatory behavior of CDK activity. Thus, one basic system for representing the CDC is a biochemical oscillator (CDK oscillator). However, genetically clonal cells divide with marked variability in their total duration of a single CDC round, exhibiting non-Gaussian statistical distributions. Therefore, the CDK oscillator model does not account for the statistical nature of cell-cycle control. Herein, we review quantitative studies of the statistical properties of the CDC. Over the past 70 years, studies have shown that the CDC is driven by a cluster of molecular oscillators. The CDK oscillator is coupled to transcriptional and mitochondrial metabolic oscillators, which cause deterministic chaotic dynamics for the CDC. Recent studies in animal embryos have raised the possibility that the dynamics of molecular oscillators underlying CDC control are affected by allometric volume scaling among the cellular compartments. Considering these studies, we discuss the idea that a cluster of molecular oscillators embedded in different cellular compartments coordinates cellular physiology and geometry for successful cell divisions.
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Affiliation(s)
| | - Hiroaki Takagi
- Department of Physics, School of Medicine, Nara Medical University, Nara, Japan
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15
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Williams CF, George CH. Connect and Conquer: Collectivized Behavior of Mitochondria and Bacteria. Front Physiol 2019; 10:340. [PMID: 30984025 PMCID: PMC6450178 DOI: 10.3389/fphys.2019.00340] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/13/2019] [Indexed: 01/21/2023] Open
Abstract
The connectedness of signaling components in network structures is a universal feature of biologic information processing. Such organization enables the transduction of complex input stimuli into coherent outputs and is essential in modulating activities as diverse as the cooperation of bacteria within populations and the dynamic organization of mitochondria within cells. Here, we highlight some common principles that underpin collectivization in bacteria and mitochondrial populations and the advantages conferred by such behavior. We discuss the concept that bacteria and mitochondria act as signal transducers of their localized metabolic environments to bring about energy-dependent clustering to modulate higher-order function across multiple scales.
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16
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Adaniya SM, O-Uchi J, Cypress MW, Kusakari Y, Jhun BS. Posttranslational modifications of mitochondrial fission and fusion proteins in cardiac physiology and pathophysiology. Am J Physiol Cell Physiol 2019; 316:C583-C604. [PMID: 30758993 DOI: 10.1152/ajpcell.00523.2018] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mitochondrial fragmentation frequently occurs in chronic pathological conditions as seen in various human diseases. In fact, abnormal mitochondrial morphology and mitochondrial dysfunction are hallmarks of heart failure (HF) in both human patients and HF animal models. A link between mitochondrial fragmentation and cardiac pathologies has been widely proposed, but the physiological relevance of mitochondrial fission and fusion in the heart is still unclear. Recent studies have increasingly shown that posttranslational modifications (PTMs) of fission and fusion proteins are capable of directly modulating the stability, localization, and/or activity of these proteins. These PTMs include phosphorylation, acetylation, ubiquitination, conjugation of small ubiquitin-like modifier proteins, O-linked-N-acetyl-glucosamine glycosylation, and proteolysis. Thus, understanding the PTMs of fission and fusion proteins may allow us to understand the complexities that determine the balance of mitochondrial fission and fusion as well as mitochondrial function in various cell types and organs including cardiomyocytes and the heart. In this review, we summarize present knowledge regarding the function and regulation of mitochondrial fission and fusion in cardiomyocytes, specifically focusing on the PTMs of each mitochondrial fission/fusion protein. We also discuss the molecular mechanisms underlying abnormal mitochondrial morphology in HF and their contributions to the development of cardiac diseases, highlighting the crucial roles of PTMs of mitochondrial fission and fusion proteins. Finally, we discuss the future potential of manipulating PTMs of fission and fusion proteins as a therapeutic strategy for preventing and/or treating HF.
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Affiliation(s)
- Stephanie M Adaniya
- Lillehei Heart Institute, Cardiovascular Division, Department of Medicine, University of Minnesota , Minneapolis, Minnesota.,Cardiovascular Research Center, Department of Medicine, Rhode Island Hospital and the Alpert Medical School of Brown University , Providence, Rhode Island
| | - Jin O-Uchi
- Lillehei Heart Institute, Cardiovascular Division, Department of Medicine, University of Minnesota , Minneapolis, Minnesota
| | - Michael W Cypress
- Lillehei Heart Institute, Cardiovascular Division, Department of Medicine, University of Minnesota , Minneapolis, Minnesota
| | - Yoichiro Kusakari
- Department of Cell Physiology, The Jikei University School of Medicine , Tokyo , Japan
| | - Bong Sook Jhun
- Lillehei Heart Institute, Cardiovascular Division, Department of Medicine, University of Minnesota , Minneapolis, Minnesota
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17
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Lloyd D, Murray DB, Aon MA, Cortassa S, Roussel MR, Beckmann M, Poole RK. Temporal metabolic partitioning of the yeast and protist cellular networks: the cell is a global scale-invariant (fractal or self-similar) multioscillator. JOURNAL OF BIOMEDICAL OPTICS 2018; 24:1-17. [PMID: 30516036 PMCID: PMC6992908 DOI: 10.1117/1.jbo.24.5.051404] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 11/01/2018] [Indexed: 06/09/2023]
Abstract
Britton Chance, electronics expert when a teenager, became an enthusiastic student of biological oscillations, passing on this enthusiasm to many students and colleagues, including one of us (DL). This historical essay traces BC's influence through the accumulated work of DL to DL's many collaborators. The overall temporal organization of mass-energy, information, and signaling networks in yeast in self-synchronized continuous cultures represents, until now, the most characterized example of in vivo elucidation of time structure. Continuous online monitoring of dissolved gases by direct measurement (membrane-inlet mass spectrometry, together with NAD(P)H and flavin fluorescence) gives strain-specific dynamic information from timescales of minutes to hours as does two-photon imaging. The predominantly oscillatory behavior of network components becomes evident, with spontaneously synchronized cellular respiration cycles between discrete periods of increased oxygen consumption (oxidative phase) and decreased oxygen consumption (reductive phase). This temperature-compensated ultradian clock provides coordination, linking temporally partitioned functions by direct feedback loops between the energetic and redox state of the cell and its growing ultrastructure. Multioscillatory outputs in dissolved gases with 13 h, 40 min, and 4 min periods gave statistical self-similarity in power spectral and relative dispersional analyses: i.e., complex nonlinear (chaotic) behavior and a functional scale-free (fractal) network operating simultaneously over several timescales.
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Affiliation(s)
- David Lloyd
- Cardiff University, School of Biosciences, Cardiff, Wales, United Kingdom
| | - Douglas B. Murray
- Keio University, Institute for Advanced Biosciences, Tsuruoka, Japan
| | - Miguel A. Aon
- National Institutes of Health, National Institute on Aging, Laboratory of Cardiovascular Science, Baltimore, Maryland, United States
| | - Sonia Cortassa
- National Institutes of Health, National Institute on Aging, Laboratory of Cardiovascular Science, Baltimore, Maryland, United States
| | - Marc R. Roussel
- University of Lethbridge, Alberta RNA Research and Training Institute and Department of Chemistry and Biochemistry, Alberta, Canada
| | - Manfred Beckmann
- Institute of Biological, Environmental and Rural, Sciences, Aberystwyth, Wales, United Kingdom
| | - Robert K. Poole
- University of Sheffield, Department of Molecular Biology and Biotechnology, Firth Court, Western Bank, Sheffield, United Kingdom
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18
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Mitochondrial network complexity emerges from fission/fusion dynamics. Sci Rep 2018; 8:363. [PMID: 29321534 PMCID: PMC5762699 DOI: 10.1038/s41598-017-18351-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 12/06/2017] [Indexed: 12/03/2022] Open
Abstract
Mitochondrial networks exhibit a variety of complex behaviors, including coordinated cell-wide oscillations of energy states as well as a phase transition (depolarization) in response to oxidative stress. Since functional and structural properties are often interwinded, here we characterized the structure of mitochondrial networks in mouse embryonic fibroblasts using network tools and percolation theory. Subsequently we perturbed the system either by promoting the fusion of mitochondrial segments or by inducing mitochondrial fission. Quantitative analysis of mitochondrial clusters revealed that structural parameters of healthy mitochondria laid in between the extremes of highly fragmented and completely fusioned networks. We confirmed our results by contrasting our empirical findings with the predictions of a recently described computational model of mitochondrial network emergence based on fission-fusion kinetics. Altogether these results offer not only an objective methodology to parametrize the complexity of this organelle but also support the idea that mitochondrial networks behave as critical systems and undergo structural phase transitions.
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19
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Kurz FT, Aon MA, O'Rourke B, Armoundas AA. Assessing Spatiotemporal and Functional Organization of Mitochondrial Networks. Methods Mol Biol 2018; 1782:383-402. [PMID: 29851013 PMCID: PMC7003721 DOI: 10.1007/978-1-4939-7831-1_23] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
The functional and spatiotemporal organization of mitochondrial redox signaling networks can be studied in detail in cardiac myocytes and neurons by assessing the time-resolved signaling traits of their individual mitochondrial components. Perturbations of the mitochondrial network through oxidative stress can lead to coordinated, cluster-bound behavior in the form of synchronized limit-cycle oscillations of mitochondrial inner membrane potentials. These oscillations are facilitated by both structural coupling through changes in the local redox balance and signaling microdomains and functional coupling that is yet poorly understood. Thus, quantifiable measures of both coupling mechanisms, local dynamic mitochondrial coupling constants and functional clustering coefficients, are likely to offer valuable information on mitochondrial network organization. We provide step-by-step methodologies on how to acquire and assess these measures for inner membrane potential fluorescence fluctuations in laser-scanning two-photon microscope recordings of cardiac myocytes and neurons, that can be applied to other tissues as well.
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MESH Headings
- Animals
- Cluster Analysis
- Fluorescent Dyes/chemistry
- Guinea Pigs
- Image Processing, Computer-Assisted/instrumentation
- Image Processing, Computer-Assisted/methods
- Membrane Potential, Mitochondrial
- Microscopy, Confocal/instrumentation
- Microscopy, Confocal/methods
- Microscopy, Fluorescence/instrumentation
- Microscopy, Fluorescence/methods
- Mitochondria, Heart/metabolism
- Mitochondrial Dynamics
- Models, Biological
- Myocytes, Cardiac/cytology
- Neurons
- Reactive Oxygen Species/metabolism
- Signal Transduction
- Software
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Affiliation(s)
- Felix T Kurz
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.
| | - Miguel A Aon
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Brian O'Rourke
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.
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20
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Mitochondrial health, the epigenome and healthspan. Clin Sci (Lond) 2017; 130:1285-305. [PMID: 27358026 DOI: 10.1042/cs20160002] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/03/2016] [Indexed: 02/07/2023]
Abstract
Food nutrients and metabolic supply-demand dynamics constitute environmental factors that interact with our genome influencing health and disease states. These gene-environment interactions converge at the metabolic-epigenome-genome axis to regulate gene expression and phenotypic outcomes. Mounting evidence indicates that nutrients and lifestyle strongly influence genome-metabolic functional interactions determining disease via altered epigenetic regulation. The mitochondrial network is a central player of the metabolic-epigenome-genome axis, regulating the level of key metabolites [NAD(+), AcCoA (acetyl CoA), ATP] acting as substrates/cofactors for acetyl transferases, kinases (e.g. protein kinase A) and deacetylases (e.g. sirtuins, SIRTs). The chromatin, an assembly of DNA and nucleoproteins, regulates the transcriptional process, acting at the epigenomic interface between metabolism and the genome. Within this framework, we review existing evidence showing that preservation of mitochondrial network function is directly involved in decreasing the rate of damage accumulation thus slowing aging and improving healthspan.
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21
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Kurz FT, Aon MA, O'Rourke B, Armoundas AA. Functional Implications of Cardiac Mitochondria Clustering. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:1-24. [PMID: 28551779 PMCID: PMC7003720 DOI: 10.1007/978-3-319-55330-6_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The spatio-temporal organization of mitochondria in cardiac myocytes facilitates myocyte-wide, cluster-bound, mitochondrial inner membrane potential oscillatory depolarizations, commonly triggered by metabolic or oxidative stressors. Local intermitochondrial coupling can be mediated by reactive oxygen species (ROS) that activate inner membrane pores to initiate a ROS-induced-ROS-release process that produces synchronized limit cycle oscillations of mitochondrial clusters within the whole mitochondrial network. The network's dynamic organization, structure and function can be assessed by quantifying dynamic local coupling constants and dynamic functional clustering coefficients, both providing information about the network's response to external stimuli. In addition to its special organization, the mitochondrial network of cardiac myocytes exhibits substrate-sensitive coupling constants and clustering coefficients. The myocyte's ability to form functional clusters of synchronously oscillating mitochondria is sensitive to conditions such as substrate availability (e.g., glucose, pyruvate, β-hydroxybutyrate), antioxidant status, respiratory chain activity, or history of oxidative challenge (e.g., ischemia-reperfusion). This underscores the relevance of quantitative methods to characterize the network's functional status as a way to assess the myocyte's resilience to pathological stressors.
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Affiliation(s)
- Felix T Kurz
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.
- Massachusetts General Hospital, Cardiovascular Research Center, Harvard Medical School, Charlestown, MA, USA.
| | - Miguel A Aon
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Brian O'Rourke
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Antonis A Armoundas
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.
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22
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Jarosz J, Ghosh S, Delbridge LMD, Petzer A, Hickey AJR, Crampin EJ, Hanssen E, Rajagopal V. Changes in mitochondrial morphology and organization can enhance energy supply from mitochondrial oxidative phosphorylation in diabetic cardiomyopathy. Am J Physiol Cell Physiol 2016; 312:C190-C197. [PMID: 27903587 DOI: 10.1152/ajpcell.00298.2016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 11/15/2016] [Accepted: 11/24/2016] [Indexed: 12/21/2022]
Abstract
Diabetic cardiomyopathy is accompanied by metabolic and ultrastructural alterations, but the impact of the structural changes on metabolism itself is yet to be determined. Morphometric analysis of mitochondrial shape and spatial organization within transverse sections of cardiomyocytes from control and streptozotocin-induced type I diabetic Sprague-Dawley rats revealed that mitochondria are 20% smaller in size while their spatial density increases by 53% in diabetic cells relative to control myocytes. Diabetic cells formed larger clusters of mitochondria (60% more mitochondria per cluster) and the effective surface-to-volume ratio of these clusters increased by 22.5%. Using a biophysical computational model we found that this increase can have a moderate compensatory effect by increasing the availability of ATP in the cytosol when ATP synthesis within the mitochondrial matrix is compromised.
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Affiliation(s)
- Jan Jarosz
- Cell Structure and Mechanobiology Group, Department of Mechanical Engineering, University of Melbourne, Parkville, Australia.,Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne, Parkville, Australia
| | - Shouryadipta Ghosh
- Cell Structure and Mechanobiology Group, Department of Mechanical Engineering, University of Melbourne, Parkville, Australia.,Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne, Parkville, Australia
| | - Lea M D Delbridge
- Department of Physiology, University of Melbourne, Parkville, Australia
| | - Amorita Petzer
- School of Biological Sciences, University of Auckland, Aukland, New Zealand
| | - Anthony J R Hickey
- School of Biological Sciences, University of Auckland, Aukland, New Zealand
| | - Edmund J Crampin
- Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne, Parkville, Australia.,School of Mathematics and Statistics, Faculty of Science, University of Melbourne, Parkville, Australia.,School of Medicine, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of Melbourne, Parkville, Australia; and
| | - Eric Hanssen
- Advanced Microscopy Facility, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Vijay Rajagopal
- Cell Structure and Mechanobiology Group, Department of Mechanical Engineering, University of Melbourne, Parkville, Australia; .,Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne, Parkville, Australia
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23
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Wang W, Gong G, Wang X, Wei-LaPierre L, Cheng H, Dirksen R, Sheu SS. Mitochondrial Flash: Integrative Reactive Oxygen Species and pH Signals in Cell and Organelle Biology. Antioxid Redox Signal 2016; 25:534-49. [PMID: 27245241 PMCID: PMC5035371 DOI: 10.1089/ars.2016.6739] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
SIGNIFICANCE Recent breakthroughs in mitochondrial research have advanced, reshaped, and revolutionized our view of the role of mitochondria in health and disease. These discoveries include the development of novel tools to probe mitochondrial biology, the molecular identification of mitochondrial functional proteins, and the emergence of new concepts and mechanisms in mitochondrial function regulation. The discovery of "mitochondrial flash" activity has provided unique insights not only into real-time visualization of individual mitochondrial redox and pH dynamics in live cells but has also advanced understanding of the excitability, autonomy, and integration of mitochondrial function in vivo. RECENT ADVANCES The mitochondrial flash is a transient and stochastic event confined within an individual mitochondrion and is observed in a wide range of organisms from plants to Caenorhabditis elegans to mammals. As flash events involve multiple transient concurrent changes within the mitochondrion (e.g., superoxide, pH, and membrane potential), a number of different mitochondrial targeted fluorescent indicators can detect flash activity. Accumulating evidence indicates that flash events reflect integrated snapshots of an intermittent mitochondrial process arising from mitochondrial respiration chain activity associated with the transient opening of the mitochondrial permeability transition pore. CRITICAL ISSUES We review the history of flash discovery, summarize current understanding of flash biology, highlight controversies regarding the relative roles of superoxide and pH signals during a flash event, and bring forth the integration of both signals in flash genesis. FUTURE DIRECTIONS Investigations using flash as a biomarker and establishing its role in cell signaling pathway will move the field forward. Antioxid. Redox Signal. 25, 534-549.
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Affiliation(s)
- Wang Wang
- 1 Department of Anesthesiology and Pain Medicine, Mitochondria and Metabolism Center, University of Washington , Seattle, Washington
| | - Guohua Gong
- 1 Department of Anesthesiology and Pain Medicine, Mitochondria and Metabolism Center, University of Washington , Seattle, Washington
| | - Xianhua Wang
- 2 State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University , Beijing, China
| | - Lan Wei-LaPierre
- 3 Department of Pharmacology and Physiology, University of Rochester Medical Center , Rochester, New York
| | - Heping Cheng
- 2 State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University , Beijing, China
| | - Robert Dirksen
- 3 Department of Pharmacology and Physiology, University of Rochester Medical Center , Rochester, New York
| | - Shey-Shing Sheu
- 4 Department of Medicine, Center for Translational Medicine, Sidney Kimmel Medical College, Thomas Jefferson University , Philadelphia, Pennsylvania
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24
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Kurz FT, Kembro JM, Flesia AG, Armoundas AA, Cortassa S, Aon MA, Lloyd D. Network dynamics: quantitative analysis of complex behavior in metabolism, organelles, and cells, from experiments to models and back. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2016; 9. [PMID: 27599643 DOI: 10.1002/wsbm.1352] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/20/2016] [Accepted: 06/23/2016] [Indexed: 12/15/2022]
Abstract
Advancing from two core traits of biological systems: multilevel network organization and nonlinearity, we review a host of novel and readily available techniques to explore and analyze their complex dynamic behavior within the framework of experimental-computational synergy. In the context of concrete biological examples, analytical methods such as wavelet, power spectra, and metabolomics-fluxomics analyses, are presented, discussed, and their strengths and limitations highlighted. Further shown is how time series from stationary and nonstationary biological variables and signals, such as membrane potential, high-throughput metabolomics, O2 and CO2 levels, bird locomotion, at the molecular, (sub)cellular, tissue, and whole organ and animal levels, can reveal important information on the properties of the underlying biological networks. Systems biology-inspired computational methods start to pave the way for addressing the integrated functional dynamics of metabolic, organelle and organ networks. As our capacity to unravel the control and regulatory properties of these networks and their dynamics under normal or pathological conditions broadens, so is our ability to address endogenous rhythms and clocks to improve health-span in human aging, and to manage complex metabolic disorders, neurodegeneration, and cancer. WIREs Syst Biol Med 2017, 9:e1352. doi: 10.1002/wsbm.1352 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Felix T Kurz
- Massachusetts General Hospital, Cardiovascular Research Center, Harvard Medical School, Charlestown, MA, USA.,Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Jackelyn M Kembro
- Instituto de Investigaciones Biológicas y Tecnológicas (IIByT-CONICET), and Instituto de Ciencia y Tecnología de los Alimentos, Cátedra de Química Biológica, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Ana G Flesia
- Centro de Investigaciones y Estudios de Matemática (CIEM-CONICET), and Facultad de Matemática, Astronomía y Física FAMAF, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Antonis A Armoundas
- Massachusetts General Hospital, Cardiovascular Research Center, Harvard Medical School, Charlestown, MA, USA
| | - Sonia Cortassa
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Miguel A Aon
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - David Lloyd
- Cardiff University School of Biosciences, Cardiff, UK
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25
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Scholkmann F. Long range physical cell-to-cell signalling via mitochondria inside membrane nanotubes: a hypothesis. Theor Biol Med Model 2016; 13:16. [PMID: 27267202 PMCID: PMC4896004 DOI: 10.1186/s12976-016-0042-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/27/2016] [Indexed: 02/07/2023] Open
Abstract
Coordinated interaction of single cells by cell-to-cell communication (signalling) enables complex behaviour necessary for the functioning of multicellular organisms. A quite newly discovered cell-to-cell signalling mechanism relies on nanotubular cell-co-cell connections, termed "membrane nanotubes" (MNTs). The present paper presents the hypothesis that mitochondria inside MNTs can form a connected structure (mitochondrial network) which enables the exchange of energy and signals between cells. It is proposed that two modes of energy and signal transmission may occur: electrical/electrochemical and electromagnetic (optical). Experimental work supporting the hypothesis is reviewed, and suggestions for future research regarding the discussed topic are given.
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Affiliation(s)
- Felix Scholkmann
- Biomedical Optics Research Laboratory, Department of Neonatology, University Hospital Zurich, University of Zurich, Frauenklinikstr. 10, 8091, Zurich, Switzerland.
- Research Office for Complex Physical and Biological Systems (ROCoS), Mutschellenstr. 179, 8038, Zurich, Switzerland.
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Abstract
Fundamental understanding of life depends on both structural and functional details at the molecular level. Continually improving means of measurement of spatial and dynamic properties of biochemical constituents and cellular components complement studies of whole organisms. Integration of the interaction of components to provide coherent behaviour depends on highly elaborate orchestration in space and time. Whereas spatial information on a nanometre resolution is available, and fast dynamic analyses provide biochemical reaction rates measured in nanoseconds, functional coordination of the system requires integrated time dependence. While we are well aware of the special complexity of living organisms, appreciation of temporal scales and their organisation in time is still fragmentary. This article summarises current developments in research on biological time on scales from nanoseconds to years, the networks that connect different time domains and the oscillations, rhythms and biological clocks that coordinate and synchronise the complexity of the living state. “It is the pattern maintained by this homeostasis, which is the touchstone of our personal identity. Our tissues change as we live: the food we eat and the air we breathe become flesh of our flesh, and bone of our bone, and the momentary elements of our flesh and bone pass out of our body every day with our excreta. We are but whirlpools in a river of ever-flowing water. We are not the stuff that abides, but patterns that perpetuate themselves”60. Wiener, 1954 “What are called structures are slow processes of long duration, functions are quick processes of short duration”61. Von Bertalanffy, 1952
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Affiliation(s)
- David Lloyd
- Cardiff School of Biosciences, Wales, UK, and the Memphys Research Group, Biochemistry and Molecular Biology Department, at the University of Southern Denmark, Odense
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Mitochondrial redox and pH signaling occurs in axonal and synaptic organelle clusters. Sci Rep 2016; 6:23251. [PMID: 27000952 PMCID: PMC4802380 DOI: 10.1038/srep23251] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 03/02/2016] [Indexed: 01/09/2023] Open
Abstract
Redox switches are important mediators in neoplastic, cardiovascular and neurological disorders. We recently identified spontaneous redox signals in neurons at the single mitochondrion level where transients of glutathione oxidation go along with shortening and re-elongation of the organelle. We now have developed advanced image and signal-processing methods to re-assess and extend previously obtained data. Here we analyze redox and pH signals of entire mitochondrial populations. In total, we quantified the effects of 628 redox and pH events in 1797 mitochondria from intercostal axons and neuromuscular synapses using optical sensors (mito-Grx1-roGFP2; mito-SypHer). We show that neuronal mitochondria can undergo multiple redox cycles exhibiting markedly different signal characteristics compared to single redox events. Redox and pH events occur more often in mitochondrial clusters (medium cluster size: 34.1 ± 4.8 μm(2)). Local clusters possess higher mitochondrial densities than the rest of the axon, suggesting morphological and functional inter-mitochondrial coupling. We find that cluster formation is redox sensitive and can be blocked by the antioxidant MitoQ. In a nerve crush paradigm, mitochondrial clusters form sequentially adjacent to the lesion site and oxidation spreads between mitochondria. Our methodology combines optical bioenergetics and advanced signal processing and allows quantitative assessment of entire mitochondrial populations.
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28
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Lloyd D, Williams CF. New tunes from the heart. Biophys J 2016; 108:1841-2. [PMID: 25902422 DOI: 10.1016/j.bpj.2015.01.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 01/23/2015] [Indexed: 10/23/2022] Open
Affiliation(s)
- David Lloyd
- Cardiff University School of Biosciences, Cardiff, Wales, United Kingdom.
| | - Catrin F Williams
- Cardiff University School of Biosciences, Cardiff, Wales, United Kingdom; School of Engineering, Centre for High Frequency Engineering, Cardiff University, Wales, United Kingdom
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