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Preminger N, Schuldiner M. Beyond fission and fusion-Diving into the mysteries of mitochondrial shape. PLoS Biol 2024; 22:e3002671. [PMID: 38949997 PMCID: PMC11216622 DOI: 10.1371/journal.pbio.3002671] [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] [Indexed: 07/03/2024] Open
Abstract
Mitochondrial shape and network formation have been primarily associated with the well-established processes of fission and fusion. However, recent research has unveiled an intricate and multifaceted landscape of mitochondrial morphology that extends far beyond the conventional fission-fusion paradigm. These less-explored dimensions harbor numerous unresolved mysteries. This review navigates through diverse processes influencing mitochondrial shape and network formation, highlighting the intriguing complexities and gaps in our understanding of mitochondrial architecture. The exploration encompasses various scales, from biophysical principles governing membrane dynamics to molecular machineries shaping mitochondria, presenting a roadmap for future research in this evolving field.
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Affiliation(s)
- Noga Preminger
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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2
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Parry HA, Willingham TB, Giordano KA, Kim Y, Qazi S, Knutson JR, Combs CA, Glancy B. Impact of capillary and sarcolemmal proximity on mitochondrial structure and energetic function in skeletal muscle. J Physiol 2024; 602:1967-1986. [PMID: 38564214 PMCID: PMC11068488 DOI: 10.1113/jp286246] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 03/08/2024] [Indexed: 04/04/2024] Open
Abstract
Mitochondria within skeletal muscle cells are located either between the muscle contractile apparatus (interfibrillar mitochondria, IFM) or beneath the cell membrane (subsarcolemmal mitochondria, SSM), with several structural and functional differences reported between IFM and SSM. However, recent 3D imaging studies demonstrate that mitochondria are particularly concentrated in the proximity of capillaries embedded in sarcolemmal grooves rather than in proximity to the sarcolemma itself (paravascular mitochondria, PVM). To evaluate the impact of capillary vs. sarcolemmal proximity, we compared the structure and function of skeletal muscle mitochondria located either lateral to embedded capillaries (PVM), adjacent to the sarcolemma but not in PVM pools (SSM) or interspersed between sarcomeres (IFM). Mitochondrial morphology and interactions were assessed by 3D electron microscopy coupled with machine learning segmentation, whereas mitochondrial energy conversion was assessed by two-photon microscopy of mitochondrial membrane potential, content, calcium, NADH redox and flux in live, intact cells. Structurally, although PVM and SSM were similarly larger than IFM, PVM were larger, rounder and had more physical connections to neighbouring mitochondria compared to both IFM and SSM. Functionally, PVM had similar or greater basal NADH flux compared to SSM and IFM, respectively, despite a more oxidized NADH pool and a greater membrane potential, signifying a greater activation of the electron transport chain in PVM. Together, these data indicate that proximity to capillaries has a greater impact on resting mitochondrial energy conversion and distribution in skeletal muscle than the sarcolemma alone. KEY POINTS: Capillaries have a greater impact on mitochondrial energy conversion in skeletal muscle than the sarcolemma. Paravascular mitochondria are larger, and the outer mitochondrial membrane is more connected with neighbouring mitochondria. Interfibrillar mitochondria are longer and have greater contact sites with other organelles (i.e. sarcoplasmic reticulum and lipid droplets). Paravascular mitochondria have greater activation of oxidative phosphorylation than interfibrillar mitochondria at rest, although this is not regulated by calcium.
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Affiliation(s)
- Hailey A. Parry
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
| | - T. Bradley Willingham
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
- Shephard Center’s Virginia C. Crawford Research Institute, Atlanta, GA, USA
| | | | - Yuho Kim
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
- University of Massachusetts, Lowell, MA,USA
| | - Shureed Qazi
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jay R. Knutson
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
| | - Christian A. Combs
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
| | - Brian Glancy
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
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3
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Coulson SZ, Duffy BM, Staples JF. Mitochondrial techniques for physiologists. Comp Biochem Physiol B Biochem Mol Biol 2024; 271:110947. [PMID: 38278207 DOI: 10.1016/j.cbpb.2024.110947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 01/28/2024]
Abstract
Mitochondria serve several important roles in maintaining cellular homeostasis, including adenosine triphosphate (ATP) synthesis, apoptotic signalling, and regulation of both reactive oxygen species (ROS) and calcium. Therefore, mitochondrial studies may reveal insights into metabolism at higher levels of physiological organization. The apparent complexity of mitochondrial function may be daunting to researchers new to mitochondrial physiology. This review is aimed, therefore, at such researchers to provide a brief, yet approachable overview of common techniques used to assess mitochondrial function. Here we discuss the use of high-resolution respirometry in mitochondrial experiments and common analytical platforms used for this technique. Next, we compare the use of common mitochondrial preparation techniques, including adherent cells, tissue homogenate, permeabilized fibers and isolated mitochondria. Finally, we outline additional techniques that can be used in tandem with high-resolution respirometry to assess additional aspects of mitochondrial metabolism, including ATP synthesis, calcium uptake, membrane potential and reactive oxygen species emission. We also include limitations to each of these techniques and outline recommendations for experimental design and interpretation. With a general understanding of methodologies commonly used to study mitochondrial physiology, experimenters may begin contributing to our understanding of this organelle, and how it affects other physiological phenotypes.
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Affiliation(s)
- Soren Z Coulson
- Department of Biology, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada.
| | - Brynne M Duffy
- Department of Biology, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada. https://twitter.com/BrynneDuffy
| | - James F Staples
- Department of Biology, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada
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4
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Nusir A, Sinclair P, Kabbani N. Mitochondrial Proteomes in Neural Cells: A Systematic Review. Biomolecules 2023; 13:1638. [PMID: 38002320 PMCID: PMC10669788 DOI: 10.3390/biom13111638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/07/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023] Open
Abstract
Mitochondria are ancient endosymbiotic double membrane organelles that support a wide range of eukaryotic cell functions through energy, metabolism, and cellular control. There are over 1000 known proteins that either reside within the mitochondria or are transiently associated with it. These mitochondrial proteins represent a functional subcellular protein network (mtProteome) that is encoded by mitochondrial and nuclear genomes and significantly varies between cell types and conditions. In neurons, the high metabolic demand and differential energy requirements at the synapses are met by specific modifications to the mtProteome, resulting in alterations in the expression and functional properties of the proteins involved in energy production and quality control, including fission and fusion. The composition of mtProteomes also impacts the localization of mitochondria in axons and dendrites with a growing number of neurodegenerative diseases associated with changes in mitochondrial proteins. This review summarizes the findings on the composition and properties of mtProteomes important for mitochondrial energy production, calcium and lipid signaling, and quality control in neural cells. We highlight strategies in mass spectrometry (MS) proteomic analysis of mtProteomes from cultured cells and tissue. The research into mtProteome composition and function provides opportunities in biomarker discovery and drug development for the treatment of metabolic and neurodegenerative disease.
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Affiliation(s)
- Aya Nusir
- Interdisciplinary Program in Neuroscience, School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
| | - Patricia Sinclair
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
| | - Nadine Kabbani
- Interdisciplinary Program in Neuroscience, School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
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5
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Zhang Z, Fan H, Richardson W, Gao BZ, Ye T. Management of autofluorescence in formaldehyde-fixed myocardium: choosing the right treatment. Eur J Histochem 2023; 67:3812. [PMID: 37781779 PMCID: PMC10614721 DOI: 10.4081/ejh.2023.3812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/28/2023] [Indexed: 10/03/2023] Open
Abstract
Autofluorescence (AF) poses challenges for detecting proteins of interest in situ when employing immunofluorescence (IF) microscopy. This interference is particularly pronounced in strongly autofluorescent tissues such as myocardium, where tissue AF can be comparable to IF. Although various histochemical methods have been developed to achieve effective AF suppression in different types of tissue, their applications on myocardial samples have not been well validated. Due to inconsistency across different autofluorescent structures in sometypes of tissue, it is unclear if these methods can effectively suppress AF across all autofluorescent structures within the myocardium. Here, we quantitatively evaluated the performance of several commonly used quenching treatments on formaldehyde-fixed myocardial samples, including 0.3 M glycine, 0.3% Sudan Black B (SBB), 0.1% and 1% sodium borohydride (NaBH4), TrueVIEW® and TrueBlack®. We further assessed their quenching performance by employing the pre-treatment and post-treatment protocols, designed to cover two common IF staining scenarios where buffers contained detergents or not. The results suggest that SBB and TrueBlack® outperform other reagents in AF suppression on formaldehyde-fixed myocardial samples in both protocols. Furthermore, we inspected the quenching performance of SBB and TrueBlack® on major autofluorescent myocardial structures and evaluated their influence on IF imaging. The results suggest that SBB outperforms TrueBlack® in quenching major autofluorescent structures, while TrueBlack® excels in preserving IF labeling signal. Surprisingly, we found the treatment of NaBH4 increased AF signal and enhanced the AF contrast of major autofluorescent structures. This finding suggests that NaBH4 has the potential to act as an AF enhancer and may facilitate the interpretation of myocardial structures without the need for counterstaining.
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Affiliation(s)
- Zhao Zhang
- Department of Bioengineering, Clemson University, Clemson, SC.
| | - Hongming Fan
- Department of Bioengineering, Clemson University, Clemson, SC.
| | - William Richardson
- Department of Chemical Engineering, University of Arkansas, Fayetteville, AR.
| | - Bruce Z Gao
- Department of Bioengineering, Clemson University, Clemson, SC.
| | - Tong Ye
- Department of Bioengineering, Clemson University, Clemson, SC; Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC.
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Flood D, Lee ES, Taylor CT. Intracellular energy production and distribution in hypoxia. J Biol Chem 2023; 299:105103. [PMID: 37507013 PMCID: PMC10480318 DOI: 10.1016/j.jbc.2023.105103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 07/17/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023] Open
Abstract
The hydrolysis of ATP is the primary source of metabolic energy for eukaryotic cells. Under physiological conditions, cells generally produce more than sufficient levels of ATP to fuel the active biological processes necessary to maintain homeostasis. However, mechanisms underpinning the distribution of ATP to subcellular microenvironments with high local demand remain poorly understood. Intracellular distribution of ATP in normal physiological conditions has been proposed to rely on passive diffusion across concentration gradients generated by ATP producing systems such as the mitochondria and the glycolytic pathway. However, subcellular microenvironments can develop with ATP deficiency due to increases in local ATP consumption. Alternatively, ATP production can be reduced during bioenergetic stress during hypoxia. Mammalian cells therefore need to have the capacity to alter their metabolism and energy distribution strategies to compensate for local ATP deficits while also controlling ATP production. It is highly likely that satisfying the bioenergetic requirements of the cell involves the regulated distribution of ATP producing systems to areas of high ATP demand within the cell. Recently, the distribution (both spatially and temporally) of ATP-producing systems has become an area of intense investigation. Here, we review what is known (and unknown) about intracellular energy production and distribution and explore potential mechanisms through which this targeted distribution can be altered in hypoxia, with the aim of stimulating investigation in this important, yet poorly understood field of research.
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Affiliation(s)
- Darragh Flood
- Conway Institute of Biomolecular and Biomedical Research and School of Medicine, University College Dublin, Dublin, Ireland
| | - Eun Sang Lee
- Conway Institute of Biomolecular and Biomedical Research and School of Medicine, University College Dublin, Dublin, Ireland
| | - Cormac T Taylor
- Conway Institute of Biomolecular and Biomedical Research and School of Medicine, University College Dublin, Dublin, Ireland.
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Yoon Y, Lee H, Federico M, Sheu SS. Non-conventional mitochondrial permeability transition: Its regulation by mitochondrial dynamics. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148914. [PMID: 36063902 PMCID: PMC9729414 DOI: 10.1016/j.bbabio.2022.148914] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/21/2022] [Accepted: 08/29/2022] [Indexed: 11/21/2022]
Abstract
Mitochondrial permeability transition (MPT) is a phenomenon that the inner mitochondrial membrane (IMM) loses its selective permeability, leading to mitochondrial dysfunction and cell injury. Electrophysiological evidence indicates the presence of a mega-channel commonly called permeability transition pore (PTP) whose opening is responsible for MPT. However, the molecular identity of the PTP is still under intensive investigations and debates, although cyclophilin D that is inhibited by cyclosporine A (CsA) is the established regulatory component of the PTP. PTP can also open transiently and functions as a rapid mitochondrial Ca2+ releasing mechanism. Mitochondrial fission and fusion, the main components of mitochondrial dynamics, control the number and size of mitochondria, and have been shown to play a role in regulating MPT directly or indirectly. Studies by us and others have indicated the potential existence of a form of transient MPT that is insensitive to CsA. This "non-conventional" MPT is regulated by mitochondrial dynamics and may serve a protective role possibly by decreasing the susceptibility for a frequent or sustained PTP opening; hence, it may have a therapeutic value in many disease conditions involving MPT.
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Affiliation(s)
- Yisang Yoon
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta 30912, GA, USA.
| | - Hakjoo Lee
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta 30912, GA, USA
| | - Marilen Federico
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Shey-Shing Sheu
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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Voglhuber J, Holzer M, Radulović S, Thai PN, Djalinac N, Matzer I, Wallner M, Bugger H, Zirlik A, Leitinger G, Dedkova EN, Bers DM, Ljubojevic-Holzer S. Functional remodelling of perinuclear mitochondria alters nucleoplasmic Ca 2+ signalling in heart failure. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210320. [PMID: 36189813 PMCID: PMC9527904 DOI: 10.1098/rstb.2021.0320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 01/23/2022] [Indexed: 11/12/2022] Open
Abstract
Mitochondrial dysfunction in cardiomyocytes is a hallmark of heart failure development. Although initial studies recognized the importance of different mitochondrial subpopulations, there is a striking lack of direct comparison of intrafibrillar (IF) versus perinuclear (PN) mitochondria during the development of HF. Here, we use multiple approaches to examine the morphology and functional properties of IF versus PN mitochondria in pressure overload-induced cardiac remodelling in mice, and in non-failing and failing human cardiomyocytes. We demonstrate that PN mitochondria from failing cardiomyocytes are more susceptible to depolarization of mitochondrial membrane potential, reactive oxygen species generation and impairment in Ca2+ uptake compared with IF mitochondria at baseline and under physiological stress protocol. We also demonstrate, for the first time to our knowledge, that under normal conditions PN mitochondrial Ca2+ uptake shapes nucleoplasmic Ca2+ transients (CaTs) and limits nucleoplasmic Ca2+ loading. The loss of PN mitochondrial Ca2+ buffering capacity translates into increased nucleoplasmic CaTs and may explain disproportionate rise in nucleoplasmic [Ca2+] in failing cardiomyocytes at increased stimulation frequencies. Therefore, a previously unidentified benefit of restoring the mitochondrial Ca2+ uptake may be normalization of nuclear Ca2+ signalling and alleviation of altered excitation-transcription, which could be an important therapeutic approach to prevent adverse cardiac remodelling. This article is part of the theme issue 'The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease'.
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Affiliation(s)
- Julia Voglhuber
- Department of Cardiology, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Michael Holzer
- BioTechMed-Graz, Graz, Austria
- Division of Pharmacology, Otto-Loewi Research Centre, Medical University of Graz, Graz, Austria
| | - Snježana Radulović
- Research Unit Electron Microscopic Techniques, Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Phung N. Thai
- Department of Internal Medicine, Cardiovascular Medicine, University of California Davis, Davis, CA, USA
| | - Natasa Djalinac
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Ingrid Matzer
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Markus Wallner
- Department of Cardiology, Medical University of Graz, Graz, Austria
- Lewis Katz School of Medicine, Temple University, Cardiovascular Research Center, Philadelphia, PA, USA
| | - Heiko Bugger
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Andreas Zirlik
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Gerd Leitinger
- Research Unit Electron Microscopic Techniques, Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Elena N. Dedkova
- Department of Pharmacology, University of California Davis, Davis, CA, USA
- Department of Molecular Biosciences, University of California Davis, Davis, CA, USA
| | - Donald M. Bers
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Senka Ljubojevic-Holzer
- Department of Cardiology, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
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Nieblas B, Pérez-Treviño P, García N. Role of mitochondria-associated endoplasmic reticulum membranes in insulin sensitivity, energy metabolism, and contraction of skeletal muscle. Front Mol Biosci 2022; 9:959844. [PMID: 36275635 PMCID: PMC9585326 DOI: 10.3389/fmolb.2022.959844] [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: 06/02/2022] [Accepted: 08/04/2022] [Indexed: 11/29/2022] Open
Abstract
Skeletal muscle has a critical role in the regulation of the energy balance of the organism, particularly as the principal tissue responsible for insulin-stimulated glucose disposal and as the major site of peripheral insulin resistance (IR), which has been related to accumulation of lipid intermediates, reduced oxidative capacity of mitochondria and endoplasmic reticulum (ER) stress. These organelles form contact sites, known as mitochondria-associated ER membranes (MAMs). This interconnection seems to be involved in various cellular processes, including Ca2+ transport and energy metabolism; therefore, MAMs could play an important role in maintaining cellular homeostasis. Evidence suggests that alterations in MAMs may contribute to IR. However, the evidence does not refer to a specific subcellular location, which is of interest due to the fact that skeletal muscle is constituted by oxidative and glycolytic fibers as well as different mitochondrial populations that appear to respond differently to stimuli and pathological conditions. In this review, we show the available evidence of possible differential responses in the formation of MAMs in skeletal muscle as well as its role in insulin signaling and the beneficial effect it could have in the regulation of energetic metabolism and muscular contraction.
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Affiliation(s)
- Bianca Nieblas
- Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey, Nuevo León, México
- Experimental Medicine and Advanced Therapies, The Institute for Obesity Research, Tecnologico de Monterrey, Monterrey, Nuevo León, México
| | - Perla Pérez-Treviño
- Experimental Medicine and Advanced Therapies, The Institute for Obesity Research, Tecnologico de Monterrey, Monterrey, Nuevo León, México
| | - Noemí García
- Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey, Nuevo León, México
- Experimental Medicine and Advanced Therapies, The Institute for Obesity Research, Tecnologico de Monterrey, Monterrey, Nuevo León, México
- *Correspondence: Noemí García,
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10
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A 3D analysis revealed complexe mitochondria morphologies in porcine cumulus cells. Sci Rep 2022; 12:15403. [PMID: 36100690 PMCID: PMC9470746 DOI: 10.1038/s41598-022-19723-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 09/02/2022] [Indexed: 11/09/2022] Open
Abstract
In the ovarian follicle, a bilateral cell-to-cell communication exists between the female germ cell and the cumulus cells which surround the oocyte. This communication allows the transit of small size molecules known to impact oocyte developmental competence. Pyruvate derivatives produced by mitochondria, are one of these transferred molecules. Interestingly, mitochondria may adopt a variety of morphologies to regulate their functions. In this study, we described mitochondrial morphologies in porcine cumulus cells. Active mitochondria were stained with TMRM (Tetramethylrhodamine, Methyl Ester, Perchlorate) and observed with 2D confocal microscopy showing mitochondria of different morphologies such as short, intermediate, long, and very long. The number of mitochondria of each phenotype was quantified in cells and the results showed that most cells contained elongated mitochondria. Scanning electron microscopy (SEM) analysis confirmed at nanoscale resolution the different mitochondrial morphologies including round, short, intermediate, and long. Interestingly, 3D visualisation by focused ion-beam scanning electron microscopy (FIB-SEM) revealed different complex mitochondrial morphologies including connected clusters of different sizes, branched mitochondria, as well as individual mitochondria. Since mitochondrial dynamics is a key regulator of function, the description of the mitochondrial network organisation will allow to further study mitochondrial dynamics in cumulus cells in response to various conditions such as in vitro maturation.
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11
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Bolaños P, Calderón JC. Excitation-contraction coupling in mammalian skeletal muscle: Blending old and last-decade research. Front Physiol 2022; 13:989796. [PMID: 36117698 PMCID: PMC9478590 DOI: 10.3389/fphys.2022.989796] [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: 07/08/2022] [Accepted: 08/08/2022] [Indexed: 11/13/2022] Open
Abstract
The excitation–contraction coupling (ECC) in skeletal muscle refers to the Ca2+-mediated link between the membrane excitation and the mechanical contraction. The initiation and propagation of an action potential through the membranous system of the sarcolemma and the tubular network lead to the activation of the Ca2+-release units (CRU): tightly coupled dihydropyridine and ryanodine (RyR) receptors. The RyR gating allows a rapid, massive, and highly regulated release of Ca2+ from the sarcoplasmic reticulum (SR). The release from triadic places generates a sarcomeric gradient of Ca2+ concentrations ([Ca2+]) depending on the distance of a subcellular region from the CRU. Upon release, the diffusing Ca2+ has multiple fates: binds to troponin C thus activating the contractile machinery, binds to classical sarcoplasmic Ca2+ buffers such as parvalbumin, adenosine triphosphate and, experimentally, fluorescent dyes, enters the mitochondria and the SR, or is recycled through the Na+/Ca2+ exchanger and store-operated Ca2+ entry (SOCE) mechanisms. To commemorate the 7th decade after being coined, we comprehensively and critically reviewed “old”, historical landmarks and well-established concepts, and blended them with recent advances to have a complete, quantitative-focused landscape of the ECC. We discuss the: 1) elucidation of the CRU structures at near-atomic resolution and its implications for functional coupling; 2) reliable quantification of peak sarcoplasmic [Ca2+] using fast, low affinity Ca2+ dyes and the relative contributions of the Ca2+-binding mechanisms to the whole concert of Ca2+ fluxes inside the fibre; 3) articulation of this novel quantitative information with the unveiled structural details of the molecular machinery involved in mitochondrial Ca2+ handing to understand how and how much Ca2+ enters the mitochondria; 4) presence of the SOCE machinery and its different modes of activation, which awaits understanding of its magnitude and relevance in situ; 5) pharmacology of the ECC, and 6) emerging topics such as the use and potential applications of super-resolution and induced pluripotent stem cells (iPSC) in ECC. Blending the old with the new works better!
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Affiliation(s)
- Pura Bolaños
- Laboratory of Cellular Physiology, Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research (IVIC), Caracas, Venezuela
| | - Juan C. Calderón
- Physiology and Biochemistry Research Group-PHYSIS, Faculty of Medicine, University of Antioquia, Medellín, Colombia
- *Correspondence: Juan C. Calderón,
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12
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Chandra Shekar K, Yannopoulos D, Kosmopoulos M, Riess ML. Differential Effects of Reperfusion on Cardiac Mitochondrial Subpopulations in a Preclinical Porcine Model of Acute Myocardial Infarction. Front Cell Dev Biol 2022; 10:843733. [PMID: 35356287 PMCID: PMC8959812 DOI: 10.3389/fcell.2022.843733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 02/03/2022] [Indexed: 11/28/2022] Open
Abstract
Acute myocardial infarction (AMI) leads to localized cardiac ischemia and can be fatal if untreated. Despite being treatable, the threat of ischemia-reperfusion (IR) injury remains high. Mitochondria are central to both propagation and mitigation of IR injury, and cardiac mitochondria are categorized into two major subtypes-subsarcolemmal and interfibrillar mitochondria (SSM and IFM, respectively). We hypothesized that, in our pre-clinical porcine model of AMI, SSM and IFM are differentially affected by reperfusion. AMI was induced in female pigs by balloon occlusion of the left anterior descending artery for 45 min, followed by 4 h of reperfusion. At the end of reperfusion, animals were euthanized. Cardiac SSM and IFM from the affected ischemic area and a nearby non-ischemic area were isolated to compare mitochondrial function using substrates targeting mitochondrial electron transport chain complexes I and II. Despite detecting overall significant differences in mitochondrial function including yield, mitochondrial S3 and S4 respirations, and calcium retention, consistent individual functional differences in the two mitochondrial subpopulations were not observed, both between the two mitochondrial subtypes, as well as between the ischemic and non-ischemic tissue. Nonetheless, this study describes the mitochondrial subtype response within the initial few hours of reperfusion in a clinically relevant model of AMI, which provides valuable information needed to develop novel mitochondrially targeted therapies for AMI.
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Affiliation(s)
- Kadambari Chandra Shekar
- Integrative Biology and Physiology, University of Minnesota at Twin Cities, St. Paul, MN, United States
| | - Demetris Yannopoulos
- Department of Cardiology, Division of Medicine, University of Minnesota at Twin Cities, St. Paul, MN, United States
| | - Marinos Kosmopoulos
- Department of Cardiology, Division of Medicine, University of Minnesota at Twin Cities, St. Paul, MN, United States
| | - Matthias L. Riess
- Anesthesiology, TVHS VA Medical Center, Nashville, TN, United States
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, United States
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States
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Analysis of Mitochondrial Function, Structure, and Intracellular Organization In Situ in Cardiomyocytes and Skeletal Muscles. Int J Mol Sci 2022; 23:ijms23042252. [PMID: 35216368 PMCID: PMC8876605 DOI: 10.3390/ijms23042252] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 01/31/2022] [Accepted: 02/07/2022] [Indexed: 01/27/2023] Open
Abstract
Analysis of the function, structure, and intracellular organization of mitochondria is important for elucidating energy metabolism and intracellular energy transfer. In addition, basic and clinically oriented studies that investigate organ/tissue/cell dysfunction in various human diseases, including myopathies, cardiac/brain ischemia-reperfusion injuries, neurodegenerative diseases, cancer, and aging, require precise estimation of mitochondrial function. It should be noted that the main metabolic and functional characteristics of mitochondria obtained in situ (in permeabilized cells and tissue samples) and in vitro (in isolated organelles) are quite different, thereby compromising interpretations of experimental and clinical data. These differences are explained by the existence of the mitochondrial network, which possesses multiple interactions between the cytoplasm and other subcellular organelles. Metabolic and functional crosstalk between mitochondria and extra-mitochondrial cellular environments plays a crucial role in the regulation of mitochondrial metabolism and physiology. Therefore, it is important to analyze mitochondria in vivo or in situ without their isolation from the natural cellular environment. This review summarizes previous studies and discusses existing approaches and methods for the analysis of mitochondrial function, structure, and intracellular organization in situ.
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14
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Energy transfer between the mitochondrial network and lipid droplets in insulin resistant skeletal muscle. CURRENT OPINION IN PHYSIOLOGY 2021; 24:100487. [PMID: 35274067 PMCID: PMC8903156 DOI: 10.1016/j.cophys.2022.100487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Mitochondria and lipid droplets in the insulin resistant skeletal muscle of type 2 diabetic individuals have both been heavily investigated independently and are characterized by more fragmented, dysfunctional mitochondrial networks and larger lipid droplets compared to skeletal muscle of healthy individuals. Specialized contacts between mitochondrial and lipid droplet membranes are known to decrease in diabetic muscle, though it remains unclear how energy transfer at the remaining mitochondria-lipid droplet contact sites may be altered by type 2 diabetes. The purpose of this review is to highlight recent data on mitochondrial structure and function and lipid droplet dynamics in type 2 diabetic skeletal muscle and to underscore the need for more detailed investigations into the functional nature of mitochondria-lipid droplet interactions in type 2 diabetes.
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15
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Abstract
Oxygen (O2) is essential for life and therefore the supply of sufficient O2 to the tissues is a major physiological challenge. In mammals, a deficit of O2 (hypoxia) triggers rapid cardiorespiratory reflexes (e.g. hyperventilation and increased heart output) that within a few seconds increase the uptake of O2 by the lungs and its distribution throughout the body. The prototypical acute O2-sensing organ is the carotid body (CB), which contains sensory glomus cells expressing O2-regulated ion channels. In response to hypoxia, glomus cells depolarize and release transmitters which activate afferent fibers terminating at the brainstem respiratory and autonomic centers. In this review, we summarize the basic properties of CB chemoreceptor cells and the essential role played by their specialized mitochondria in acute O2 sensing and signaling. We focus on recent data supporting a "mitochondria-to-membrane signaling" model of CB chemosensory transduction. The possibility that the differential expression of specific subunit isoforms and enzymes could allow mitochondria to play a generalized adaptive O2-sensing and signaling role in a wide variety of cells is also discussed.
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Affiliation(s)
- José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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16
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Silaghi CN, Farcaș M, Crăciun AM. Sirtuin 3 (SIRT3) Pathways in Age-Related Cardiovascular and Neurodegenerative Diseases. Biomedicines 2021; 9:biomedicines9111574. [PMID: 34829803 PMCID: PMC8615405 DOI: 10.3390/biomedicines9111574] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/22/2021] [Accepted: 10/27/2021] [Indexed: 01/08/2023] Open
Abstract
Age-associated cardiovascular and neurodegenerative diseases lead to high morbidity and mortality around the world. Sirtuins are vital enzymes for metabolic adaptation and provide protective effects against a wide spectrum of pathologies. Among sirtuins, mitochondrial sirtuin 3 (SIRT3) is an essential player in preserving the habitual metabolic profile. SIRT3 activity declines as a result of aging-induced changes in cellular metabolism, leading to increased susceptibility to endothelial dysfunction, hypertension, heart failure and neurodegenerative diseases. Stimulating SIRT3 activity via lifestyle, pharmacological or genetic interventions could protect against a plethora of pathologies and could improve health and lifespan. Thus, understanding how SIRT3 operates and how its protective effects could be amplified, will aid in treating age-associated diseases and ultimately, in enhancing the quality of life in elders.
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17
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Ngo J, Osto C, Villalobos F, Shirihai OS. Mitochondrial Heterogeneity in Metabolic Diseases. BIOLOGY 2021; 10:biology10090927. [PMID: 34571805 PMCID: PMC8470264 DOI: 10.3390/biology10090927] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/03/2021] [Accepted: 09/08/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary Often times mitochondria within a single cell are depicted as homogenous entities both morphologically and functionally. In normal and diseased states, mitochondria are heterogeneous and display distinct functional properties. In both cases, mitochondria exhibit differences in morphology, membrane potential, and mitochondrial calcium levels. However, the degree of heterogeneity is different during disease; or rather, heterogeneity at the physiological state stems from physically distinct mitochondrial subpopulations. Overall, mitochondrial heterogeneity is both beneficial and detrimental to the cellular system; protective in enabling cellular adaptation to biological stress or detrimental in inhibiting protective mechanisms. Abstract Mitochondria have distinct architectural features and biochemical functions consistent with cell-specific bioenergetic needs. However, as imaging and isolation techniques advance, heterogeneity amongst mitochondria has been observed to occur within the same cell. Moreover, mitochondrial heterogeneity is associated with functional differences in metabolic signaling, fuel utilization, and triglyceride synthesis. These phenotypic associations suggest that mitochondrial subpopulations and heterogeneity influence the risk of metabolic diseases. This review examines the current literature regarding mitochondrial heterogeneity in the pancreatic beta-cell and renal proximal tubules as they exist in the pathological and physiological states; specifically, pathological states of glucolipotoxicity, progression of type 2 diabetes, and kidney diseases. Emphasis will be placed on the benefits of balancing mitochondrial heterogeneity and how the disruption of balancing heterogeneity leads to impaired tissue function and disease onset.
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Affiliation(s)
- Jennifer Ngo
- Department of Medicine, Division of Endocrinology, David Geffen School of Medicine at UCLA, 650 Charles E. Young Drive East, Los Angeles, CA 90095, USA; (J.N.); (C.O.); (F.V.)
- Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
- Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Corey Osto
- Department of Medicine, Division of Endocrinology, David Geffen School of Medicine at UCLA, 650 Charles E. Young Drive East, Los Angeles, CA 90095, USA; (J.N.); (C.O.); (F.V.)
- Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, 650 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - Frankie Villalobos
- Department of Medicine, Division of Endocrinology, David Geffen School of Medicine at UCLA, 650 Charles E. Young Drive East, Los Angeles, CA 90095, USA; (J.N.); (C.O.); (F.V.)
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095, USA
| | - Orian S. Shirihai
- Department of Medicine, Division of Endocrinology, David Geffen School of Medicine at UCLA, 650 Charles E. Young Drive East, Los Angeles, CA 90095, USA; (J.N.); (C.O.); (F.V.)
- Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, 650 Charles E. Young Drive East, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
- Correspondence:
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18
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Mitochondrial Protein Abundance Gradients Require the Distribution of Separated Mitochondria. BIOLOGY 2021; 10:biology10070572. [PMID: 34201436 PMCID: PMC8301041 DOI: 10.3390/biology10070572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/14/2021] [Accepted: 06/18/2021] [Indexed: 01/06/2023]
Abstract
Mitochondria are highly dynamic organelles that interchange their contents mediated by fission and fusion. However, it has previously been shown that the mitochondria of cultured human epithelial cells exhibit a gradient in the relative abundance of several proteins, with the perinuclear mitochondria generally exhibiting a higher protein abundance than the peripheral mitochondria. The molecular mechanisms that are required for the establishment and the maintenance of such inner-cellular mitochondrial protein abundance gradients are unknown. We verified the existence of inner-cellular gradients in the abundance of clusters of the mitochondrial outer membrane protein Tom20 in the mitochondria of kidney epithelial cells from an African green monkey (Vero cells) using STED nanoscopy and confocal microscopy. We found that the Tom20 gradients are established immediately after cell division and require the presence of microtubules. Furthermore, the gradients are abrogated in hyperfused mitochondrial networks. Our results suggest that inner-cellular protein abundance gradients from the perinuclear to the peripheral mitochondria are established by the trafficking of individual mitochondria to their respective cellular destination.
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19
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Oliveira MF, Medeiros RCA, Mietto BS, Calvo TL, Mendonça APM, Rosa TLSA, Silva DSD, Vasconcelos KGDCD, Pereira AMR, de Macedo CS, Pereira GMB, Moreira MDBP, Pessolani MCV, Moraes MO, Lara FA. Reduction of host cell mitochondrial activity as Mycobacterium leprae's strategy to evade host innate immunity. Immunol Rev 2021; 301:193-208. [PMID: 33913182 PMCID: PMC10084840 DOI: 10.1111/imr.12962] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 12/20/2022]
Abstract
Leprosy is a much-feared incapacitating infectious disease caused by Mycobacterium leprae or M lepromatosis, annually affecting roughly 200,000 people worldwide. During host-pathogen interaction, M leprae subverts the immune response, leading to development of disease. Throughout the last few decades, the impact of energy metabolism on the control of intracellular pathogens and leukocytic differentiation has become more evident. Mitochondria play a key role in regulating newly-discovered immune signaling pathways by controlling redox metabolism and the flow of energy besides activating inflammasome, xenophagy, and apoptosis. Likewise, this organelle, whose origin is probably an alphaproteobacterium, directly controls the intracellular pathogens attempting to invade its niche, a feature conquered at the expense of billions of years of coevolution. In the present review, we discuss the role of reduced host cell mitochondrial activity during M leprae infection and the consequential fates of M leprae and host innate immunity. Conceivably, inhibition of mitochondrial energy metabolism emerges as an overlooked and novel mechanism developed by M leprae to evade xenophagy and the host immune response.
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Affiliation(s)
- Marcus Fernandes Oliveira
- Laboratório de Bioquímica de Resposta ao Estresse, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Bruno Siqueira Mietto
- Instituto de Ciências Biológicas, Universidade Federal de Juiz de Fora, Minas Gerais, Brazil
| | - Thyago Leal Calvo
- Laboratório de Hanseníase, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Ana Paula Miranda Mendonça
- Laboratório de Bioquímica de Resposta ao Estresse, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | | | | | | | - Cristiana Santos de Macedo
- Laboratório de Microbiologia Celular, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.,Centro de Desenvolvimento Tecnológico em Saúde, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | | | | | | | | | - F A Lara
- Laboratório de Microbiologia Celular, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
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20
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Kuznetsov AV, Javadov S, Margreiter R, Grimm M, Hagenbuchner J, Ausserlechner MJ. Structural and functional remodeling of mitochondria as an adaptive response to energy deprivation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148393. [PMID: 33549532 DOI: 10.1016/j.bbabio.2021.148393] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 01/21/2021] [Accepted: 01/31/2021] [Indexed: 01/23/2023]
Abstract
Cancer cells bioenergetics is more dependent on glycolysis than mitochondrial oxidative phosphorylation, a phenomenon known as the Warburg Effect. It has been proposed that inhibition of glycolysis may selectively affect cancer cells. However, the effects of glycolysis inhibition on mitochondrial function and structure in cancer cells are not completely understood. Here, we investigated the comparative effects of 2-deoxy-d-glucose (2-DG, a glucose analogue, which suppresses cellular glycolysis) on cellular bioenergetics in human colon cancer DLD-1 cells, smooth muscle cells, human umbilical vein endothelial cells and HL-1 cardiomyocytes. In all cells, 2-DG treatment resulted in significant ATP depletion, however, the cell viability remained unchanged. Also, we did not observe the synergistic effects of 2-DG with anticancer drugs doxorubicin and 5-fluorouracil. Instead, after 2-DG treatment and ATP depletion, mitochondrial respiration and membrane potential were significantly enhanced and mitochondrial morphology changed in the direction of more network organization. Analysis of protein expression demonstrated that 2-DG treatment induced an activation of AMPK (elevated pAMPK/AMPK ratio), increased mitochondrial fusion (mitofusins 1 and 2) and decreased fission (Drp1) proteins. In conclusion, this study suggests a strong link between respiratory function and structural organization of mitochondria in the cell. We propose that the functionality of the mitochondrial network is enhanced compared to disconnected mitochondria.
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Affiliation(s)
- Andrey V Kuznetsov
- Cardiac Surgery Research Laboratory, Department of Cardiac Surgery, Innsbruck Medical University, Innsbruck, Austria; Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria.
| | - Sabzali Javadov
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, PR, USA.
| | - Raimund Margreiter
- Department of Visceral, Transplant and Thoracic Surgery, Medical University of Innsbruck, Innsbruck, Austria.
| | - Michael Grimm
- Cardiac Surgery Research Laboratory, Department of Cardiac Surgery, Innsbruck Medical University, Innsbruck, Austria.
| | - Judith Hagenbuchner
- Department of Pediatrics II, Medical University of Innsbruck, Innsbruck, Austria.
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21
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Glancy B, Kim Y, Katti P, Willingham TB. The Functional Impact of Mitochondrial Structure Across Subcellular Scales. Front Physiol 2020; 11:541040. [PMID: 33262702 PMCID: PMC7686514 DOI: 10.3389/fphys.2020.541040] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 10/20/2020] [Indexed: 12/12/2022] Open
Abstract
Mitochondria are key determinants of cellular health. However, the functional role of mitochondria varies from cell to cell depending on the relative demands for energy distribution, metabolite biosynthesis, and/or signaling. In order to support the specific needs of different cell types, mitochondrial functional capacity can be optimized in part by modulating mitochondrial structure across several different spatial scales. Here we discuss the functional implications of altering mitochondrial structure with an emphasis on the physiological trade-offs associated with different mitochondrial configurations. Within a mitochondrion, increasing the amount of cristae in the inner membrane improves capacity for energy conversion and free radical-mediated signaling but may come at the expense of matrix space where enzymes critical for metabolite biosynthesis and signaling reside. Electrically isolating individual cristae could provide a protective mechanism to limit the spread of dysfunction within a mitochondrion but may also slow the response time to an increase in cellular energy demand. For individual mitochondria, those with relatively greater surface areas can facilitate interactions with the cytosol or other organelles but may be more costly to remove through mitophagy due to the need for larger phagophore membranes. At the network scale, a large, stable mitochondrial reticulum can provide a structural pathway for energy distribution and communication across long distances yet also enable rapid spreading of localized dysfunction. Highly dynamic mitochondrial networks allow for frequent content mixing and communication but require constant cellular remodeling to accommodate the movement of mitochondria. The formation of contact sites between mitochondria and several other organelles provides a mechanism for specialized communication and direct content transfer between organelles. However, increasing the number of contact sites between mitochondria and any given organelle reduces the mitochondrial surface area available for contact sites with other organelles as well as for metabolite exchange with cytosol. Though the precise mechanisms guiding the coordinated multi-scale mitochondrial configurations observed in different cell types have yet to be elucidated, it is clear that mitochondrial structure is tailored at every level to optimize mitochondrial function to meet specific cellular demands.
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Affiliation(s)
- Brian Glancy
- Muscle Energetics Laboratory, NHLBI, National Institutes of Health, Bethesda, MD, United States
- NIAMS, National Institutes of Health, Bethesda, MD, United States
| | - Yuho Kim
- Muscle Energetics Laboratory, NHLBI, National Institutes of Health, Bethesda, MD, United States
- Department of Physical Therapy and Kinesiology, University of Massachusetts Lowell, Lowell, MA, United States
| | - Prasanna Katti
- Muscle Energetics Laboratory, NHLBI, National Institutes of Health, Bethesda, MD, United States
| | - T. Bradley Willingham
- Muscle Energetics Laboratory, NHLBI, National Institutes of Health, Bethesda, MD, United States
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22
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Cho HM, Sun W. Molecular cross talk among the components of the regulatory machinery of mitochondrial structure and quality control. Exp Mol Med 2020; 52:730-737. [PMID: 32398745 PMCID: PMC7272630 DOI: 10.1038/s12276-020-0434-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/23/2020] [Accepted: 03/25/2020] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial dysfunction critically impairs cellular health and often causes or affects the progression of several diseases, including neurodegenerative diseases and cancer. Thus, cells must have several ways to monitor the condition of mitochondrial quality and maintain mitochondrial health. Accumulating evidence suggests that the molecular machinery responding to spontaneous changes in mitochondrial morphology is associated with the routine mitochondrial quality control system. In this short review, we discuss recent progress made in linking mitochondrial structural dynamics and the quality control system. The health of mitochondria is important for cellular health, and is maintained by the same mechanisms that control their shape. Mitochondria continuously divide, fuse, elongate, and shrink, forming ever-changing networks inside cells. Damaged mitochondria produce toxic byproducts and have been implicated in neurodegenerative diseases and cancer. Although changes in mitochondrial structure are known to be related to cellular health, the detailed mechanisms are not well understood. In a review, Woong Sun and Hyo Min Cho at the Korea University College of Medicine, Seoul, detail how mitochondrial fusion, division, and recycling are controlled, what signals are used to dispose of damaged mitochondria, and how the shape-control mechanisms also regulate mitochondrial quality. This review will help us to more clearly understand the structure-function relationship of mitochondria.
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Affiliation(s)
- Hyo Min Cho
- Department of Anatomy, Korea University College of Medicine, Brain Korea 21 plus, Seoul, 02841, Republic of Korea
| | - Woong Sun
- Department of Anatomy, Korea University College of Medicine, Brain Korea 21 plus, Seoul, 02841, Republic of Korea.
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23
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Knorre DA. Intracellular quality control of mitochondrial DNA: evidence and limitations. Philos Trans R Soc Lond B Biol Sci 2019; 375:20190176. [PMID: 31787047 DOI: 10.1098/rstb.2019.0176] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Eukaryotic cells can harbour mitochondria with markedly different transmembrane potentials. Intracellular mitochondrial quality-control mechanisms (e.g. mitophagy) rely on this intracellular variation to distinguish functional and damaged (depolarized) mitochondria. Given that intracellular mitochondrial DNA (mtDNA) genetic variation can induce mitochondrial heterogeneity, mitophagy could remove deleterious mtDNA variants in cells. However, the reliance of mitophagy on the mitochondrial transmembrane potential suggests that mtDNAs with deleterious mutations in ATP synthase can evade the control. This evasion is possible because inhibition of ATP synthase can increase the mitochondrial transmembrane potential. Moreover, the linkage of the mtDNA genotype to individual mitochondrial performance is expected to be weak owing to intracellular mitochondrial intercomplementation. Nonetheless, I reason that intracellular mtDNA quality control is possible and crucial at the zygote stage of the life cycle. Indeed, species with biparental mtDNA inheritance or frequent 'leakage' of paternal mtDNA can be vulnerable to invasion of selfish mtDNAs at the stage of gamete fusion. Here, I critically review recent findings on intracellular mtDNA quality control by mitophagy and discuss other mechanisms by which the nuclear genome can affect the competition of mtDNA variants in the cell. This article is part of the theme issue 'Linking the mitochondrial genotype to phenotype: a complex endeavour'.
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Affiliation(s)
- Dmitry A Knorre
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Leninskiye Gory 1-40, Moscow 119991, Russia.,Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Trubetskaya Str. 8-2, Moscow 119991, Russia
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24
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Benigni A, Cassis P, Conti S, Perico L, Corna D, Cerullo D, Zentilin L, Zoja C, Perna A, Lionetti V, Giacca M, Trionfini P, Tomasoni S, Remuzzi G. Sirt3 Deficiency Shortens Life Span and Impairs Cardiac Mitochondrial Function Rescued by Opa1 Gene Transfer. Antioxid Redox Signal 2019; 31:1255-1271. [PMID: 31269804 DOI: 10.1089/ars.2018.7703] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Aims: Sirtuins, a family of NAD+-dependent deacetylases, are recognized as nondispensable regulators of aging processes. Sirtuin 3 (SIRT3) is the main mitochondrial deacetylase that maintains mitochondrial bioenergetics, an essential prerequisite for healthy aging. In this study, using Sirt3 knockout (Sirt3-/-) mice, we sought to establish whether Sirt3 deficiency affected life span, an endpoint that has never been tested formally in mammals, and uncover the mechanisms involved in organ damage associated with aging. Results:Sirt3-/- mice experienced a shorter life span than wild-type mice and severe cardiac damage, characterized by hypertrophy and fibrosis, as they aged. No alterations were found in organs other than the heart. Sirt3 deficiency altered cardiac mitochondrial bioenergetics and caused hyperacetylation of optic atrophy 1 (OPA1), a SIRT3 target. These changes were associated with aberrant alignment of trans-mitochondrial cristae in cardiomyocytes, and cardiac dysfunction. Gene transfer of deacetylated Opa1 restored cristae alignment in Sirt3-/- mice, ameliorated cardiac reserve capacity, and protected the heart against hypertrophy and fibrosis. The translational relevance of these findings is in the data showing that SIRT3 silencing in human-induced pluripotent stem cell-derived cardiomyocytes led to mitochondrial dysfunction and altered contractile phenotype, both rescued by Opa1 gene transfer. Innovation: Our findings indicate that future approaches to heart failure could include SIRT3 as a plausible therapeutic target. Conclusion: SIRT3 has a major role in regulating mammalian life span. Sirt3 deficiency leads to cardiac abnormalities, due to defective trans-mitochondrial cristae alignment and impaired mitochondrial bioenergetics. Correcting cardiac OPA1 hyperacetylation through gene transfer diminished heart failure in Sirt3-/- mice during aging. Antioxid. Redox Signal. 31, 1255-1271.
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Affiliation(s)
- Ariela Benigni
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Paola Cassis
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Sara Conti
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Luca Perico
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Daniela Corna
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Domenico Cerullo
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Lorena Zentilin
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Carlamaria Zoja
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Annalisa Perna
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Vincenzo Lionetti
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy.,UOS Anesthesia and Intensive Care, Fondazione Toscana "G. Monasterio", Pisa, Italy
| | - Mauro Giacca
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy.,Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Piera Trionfini
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Susanna Tomasoni
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy
| | - Giuseppe Remuzzi
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Centro Anna Maria Astori, Science and Technology Park Kilometro Rosso, Bergamo, Italy.,L. Sacco' Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
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25
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Velásquez E, Martins-de-Souza D, Velásquez I, Carneiro GRA, Schmitt A, Falkai P, Domont GB, Nogueira FCS. Quantitative Subcellular Proteomics of the Orbitofrontal Cortex of Schizophrenia Patients. J Proteome Res 2019; 18:4240-4253. [PMID: 31581776 DOI: 10.1021/acs.jproteome.9b00398] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Schizophrenia is a chronic disease characterized by the impairment of mental functions with a marked social dysfunction. A quantitative proteomic approach using iTRAQ labeling and SRM, applied to the characterization of mitochondria (MIT), crude nuclear fraction (NUC), and cytoplasm (CYT), can allow the observation of dynamic changes in cell compartments providing valuable insights concerning schizophrenia physiopathology. Mass spectrometry analyses of the orbitofrontal cortex from 12 schizophrenia patients and 8 healthy controls identified 655 protein groups in the MIT fraction, 1500 in NUC, and 1591 in CYT. We found 166 groups of proteins dysregulated among all enriched cellular fractions. Through the quantitative proteomic analysis, we detect as the main biological pathways those related to calcium and glutamate imbalance, cell signaling disruption of CREB activation, axon guidance, and proteins involved in the activation of NF-kB signaling along with the increase of complement protein C3. Based on our data analysis, we suggest the activation of NF-kB as a possible pathway that links the deregulation of glutamate, calcium, apoptosis, and the activation of the immune system in schizophrenia patients. All MS data are available in the ProteomeXchange Repository under the identifier PXD015356 and PXD014350.
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Affiliation(s)
- Erika Velásquez
- Proteomics Unit, Department of Biochemistry, Institute of Chemistry , Federal University of Rio de Janeiro , Rio de Janeiro 21941-909 , Brazil
| | - Daniel Martins-de-Souza
- Laboratory of Neuroproteomics, Department of Biochemistry, Institute of Biology , University of Campinas (UNICAMP) , Campinas 13083-970 , Brazil.,Experimental Medicine Research Cluster (EMRC) University of Campinas , Campinas 13083-887 , SP , Brazil.,Instituto Nacional de Biomarcadores em Neuropsiquiatria (INBION) , Conselho Nacional de Desenvolvimento Cientı́fico e Tecnológico (CNPq) , São Paulo , Brazil
| | | | - Gabriel Reis Alves Carneiro
- Laboratory of Proteomics, LADETEC, Institute of Chemistry , Federal University of Rio de Janeiro , Rio de Janeiro 21941-598 , Brazil
| | - Andrea Schmitt
- Department of Psychiatry and Psychotherapy , Ludwig Maximilian University of Munich (LMU) , 80539 Munich , Germany
| | - Peter Falkai
- Department of Psychiatry and Psychotherapy , Ludwig Maximilian University of Munich (LMU) , 80539 Munich , Germany
| | - Gilberto B Domont
- Proteomics Unit, Department of Biochemistry, Institute of Chemistry , Federal University of Rio de Janeiro , Rio de Janeiro 21941-909 , Brazil
| | - Fabio C S Nogueira
- Proteomics Unit, Department of Biochemistry, Institute of Chemistry , Federal University of Rio de Janeiro , Rio de Janeiro 21941-909 , Brazil.,Laboratory of Proteomics, LADETEC, Institute of Chemistry , Federal University of Rio de Janeiro , Rio de Janeiro 21941-598 , Brazil
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26
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The Role of Mitochondria in the Mechanisms of Cardiac Ischemia-Reperfusion Injury. Antioxidants (Basel) 2019; 8:antiox8100454. [PMID: 31590423 PMCID: PMC6826663 DOI: 10.3390/antiox8100454] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 09/30/2019] [Accepted: 10/01/2019] [Indexed: 01/11/2023] Open
Abstract
Mitochondria play a critical role in maintaining cellular function by ATP production. They are also a source of reactive oxygen species (ROS) and proapoptotic factors. The role of mitochondria has been established in many aspects of cell physiology/pathophysiology, including cell signaling. Mitochondria may deteriorate under various pathological conditions, including ischemia-reperfusion (IR) injury. Mitochondrial injury can be one of the main causes for cardiac and other tissue injuries by energy stress and overproduction of toxic reactive oxygen species, leading to oxidative stress, elevated calcium and apoptotic and necrotic cell death. However, the interplay among these processes in normal and pathological conditions is still poorly understood. Mitochondria play a critical role in cardiac IR injury, where they are directly involved in several pathophysiological mechanisms. We also discuss the role of mitochondria in the context of mitochondrial dynamics, specializations and heterogeneity. Also, we wanted to stress the existence of morphologically and functionally different mitochondrial subpopulations in the heart that may have different sensitivities to diseases and IR injury. Therefore, various cardioprotective interventions that modulate mitochondrial stability, dynamics and turnover, including various pharmacologic agents, specific mitochondrial antioxidants and uncouplers, and ischemic preconditioning can be considered as the main strategies to protect mitochondrial and cardiovascular function and thus enhance longevity.
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27
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Caporizzo MA, Chen CY, Prosser BL. Cardiac microtubules in health and heart disease. Exp Biol Med (Maywood) 2019; 244:1255-1272. [PMID: 31398994 DOI: 10.1177/1535370219868960] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cardiomyocytes are large (∼40,000 µm3), rod-shaped muscle cells that provide the working force behind each heartbeat. These highly structured cells are packed with dense cytoskeletal networks that can be divided into two groups—the contractile (i.e. sarcomeric) cytoskeleton that consists of filamentous actin-myosin arrays organized into myofibrils, and the non-sarcomeric cytoskeleton, which is composed of β- and γ-actin, microtubules, and intermediate filaments. Together, microtubules and intermediate filaments form a cross-linked scaffold, and these networks are responsible for the delivery of intracellular cargo, the transmission of mechanical signals, the shaping of membrane systems, and the organization of myofibrils and organelles. Microtubules are extensively altered as part of both adaptive and pathological cardiac remodeling, which has diverse ramifications for the structure and function of the cardiomyocyte. In heart failure, the proliferation and post-translational modification of the microtubule network is linked to a number of maladaptive processes, including the mechanical impediment of cardiomyocyte contraction and relaxation. This raises the possibility that reversing microtubule alterations could improve cardiac performance, yet therapeutic efforts will strongly benefit from a deeper understanding of basic microtubule biology in the heart. The aim of this review is to summarize the known physiological roles of the cardiomyocyte microtubule network, the consequences of its pathological remodeling, and to highlight the open and intriguing questions regarding cardiac microtubules. Impact statement Advancements in cell biological and biophysical approaches and super-resolution imaging have greatly broadened our view of tubulin biology over the last decade. In the heart, microtubules and microtubule-based transport help to organize and maintain key structures within the cardiomyocyte, including the sarcomere, intercalated disc, protein clearance machinery and transverse-tubule and sarcoplasmic reticulum membranes. It has become increasingly clear that post translational regulation of microtubules is a key determinant of their sub-cellular functionality. Alterations in microtubule network density, stability, and post-translational modifications are hallmarks of pathological cardiac remodeling, and modified microtubules can directly impede cardiomyocyte contractile function in various forms of heart disease. This review summarizes the functional roles and multi-leveled regulation of the cardiac microtubule cytoskeleton and highlights how refined experimental techniques are shedding mechanistic clarity on the regionally specified roles of microtubules in cardiac physiology and pathophysiology.
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Affiliation(s)
- Matthew A Caporizzo
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Christina Yingxian Chen
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Benjamin L Prosser
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.,Penn Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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28
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MacDonald JA, Bothun AM, Annis SN, Sheehan H, Ray S, Gao Y, Ivanov AR, Khrapko K, Tilly JL, Woods DC. A nanoscale, multi-parametric flow cytometry-based platform to study mitochondrial heterogeneity and mitochondrial DNA dynamics. Commun Biol 2019; 2:258. [PMID: 31312727 PMCID: PMC6624292 DOI: 10.1038/s42003-019-0513-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 06/18/2019] [Indexed: 12/27/2022] Open
Abstract
Mitochondria are well-characterized regarding their function in both energy production and regulation of cell death; however, the heterogeneity that exists within mitochondrial populations is poorly understood. Typically analyzed as pooled samples comprised of millions of individual mitochondria, there is little information regarding potentially different functionality across subpopulations of mitochondria. Herein we present a new methodology to analyze mitochondria as individual components of a complex and heterogeneous network, using a nanoscale and multi-parametric flow cytometry-based platform. We validate the platform using multiple downstream assays, including electron microscopy, ATP generation, quantitative mass-spectrometry proteomic profiling, and mtDNA analysis at the level of single organelles. These strategies allow robust analysis and isolation of mitochondrial subpopulations to more broadly elucidate the underlying complexities of mitochondria as these organelles function collectively within a cell.
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Affiliation(s)
- Julie A. MacDonald
- Department of Biology, Laboratory of Aging and Infertility Research, Northeastern University, Boston, MA 02115 USA
| | - Alisha M. Bothun
- Department of Biology, Laboratory of Aging and Infertility Research, Northeastern University, Boston, MA 02115 USA
| | - Sofia N. Annis
- Department of Biology, Laboratory of Aging and Infertility Research, Northeastern University, Boston, MA 02115 USA
| | - Hannah Sheehan
- Department of Biology, Laboratory of Aging and Infertility Research, Northeastern University, Boston, MA 02115 USA
| | - Somak Ray
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115 USA
- Barnett Institute for Chemical and Biological Analysis, Northeastern University, Boston, MA 02115 USA
| | - Yuanwei Gao
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115 USA
- Barnett Institute for Chemical and Biological Analysis, Northeastern University, Boston, MA 02115 USA
| | - Alexander R. Ivanov
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115 USA
- Barnett Institute for Chemical and Biological Analysis, Northeastern University, Boston, MA 02115 USA
| | - Konstantin Khrapko
- Department of Biology, Laboratory of Aging and Infertility Research, Northeastern University, Boston, MA 02115 USA
| | - Jonathan L. Tilly
- Department of Biology, Laboratory of Aging and Infertility Research, Northeastern University, Boston, MA 02115 USA
| | - Dori C. Woods
- Department of Biology, Laboratory of Aging and Infertility Research, Northeastern University, Boston, MA 02115 USA
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29
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Hao L, Li ZW, Zhang DY, He L, Liu W, Yang J, Tan CP, Ji LN, Mao ZW. Monitoring mitochondrial viscosity with anticancer phosphorescent Ir(iii) complexes via two-photon lifetime imaging. Chem Sci 2018; 10:1285-1293. [PMID: 30809342 PMCID: PMC6357858 DOI: 10.1039/c8sc04242j] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/03/2018] [Indexed: 12/19/2022] Open
Abstract
Precise quantitative measurement of viscosity at the subcellular level presents great challenges. Two-photon phosphorescence lifetime imaging microscopy (TPPLIM) can reflect micro-environmental changes of a chromophore in a quantitative manner. Phosphorescent iridium complexes are potential TPPLIM probes due to their rich photophysical properties including environment-sensitive long-lifetime emission and high two-photon absorption (TPA) properties. In this work, a series of iridium(iii) complexes containing rotatable groups are developed as mitochondria-targeting anticancer agents and quantitative viscosity probes. Among them, Ir6 ([Ir(ppy-CHO)2(dppe)]PF6; ppy-CHO: 4-(2-pyridyl)benzaldehyde; dppe: cis-1,2-bis(diphenylphosphino)ethene) shows satisfactory TPA properties and long lifetimes (up to 1 μs). The emission intensities and lifetimes of Ir6 are viscosity-dependent, which is mainly attributed to the configurational changes in the diphosphine ligand as proved by 1H NMR spectra. Ir6 displays potent cytotoxicity, and mechanism investigations show that it can accumulate in mitochondria and induce apoptotic cell death. Moreover, Ir6 can induce mitochondrial dysfunction and monitor the changes in mitochondrial viscosity simultaneously in a real-time and quantitative manner via TPPLIM. Upon Ir6 treatment, a time-dependent increase in viscosity and heterogeneity is observed along with the loss of membrane potential in mitochondria. In summary, our work shows that multifunctional phosphorescent metal complexes can induce and precisely detect microenvironmental changes simultaneously at the subcellular level using TPPLIM, which may deepen the understanding of the cell death mechanisms induced by these metallocompounds.
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Affiliation(s)
- Liang Hao
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry , School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China . ;
| | - Zhi-Wei Li
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry , School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China . ;
| | - Dong-Yang Zhang
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry , School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China . ;
| | - Liang He
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry , School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China . ;
| | - Wenting Liu
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry , School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China . ;
| | - Jing Yang
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry , School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China . ;
| | - Cai-Ping Tan
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry , School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China . ;
| | - Liang-Nian Ji
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry , School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China . ;
| | - Zong-Wan Mao
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry , School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China . ;
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30
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Kwong JQ, Huo J, Bround MJ, Boyer JG, Schwanekamp JA, Ghazal N, Maxwell JT, Jang YC, Khuchua Z, Shi K, Bers DM, Davis J, Molkentin JD. The mitochondrial calcium uniporter underlies metabolic fuel preference in skeletal muscle. JCI Insight 2018; 3:121689. [PMID: 30429366 DOI: 10.1172/jci.insight.121689] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 10/04/2018] [Indexed: 01/17/2023] Open
Abstract
The mitochondrial Ca2+ uniporter (MCU) complex mediates acute mitochondrial Ca2+ influx. In skeletal muscle, MCU links Ca2+ signaling to energy production by directly enhancing the activity of key metabolic enzymes in the mitochondria. Here, we examined the role of MCU in skeletal muscle development and metabolic function by generating mouse models for the targeted deletion of Mcu in embryonic, postnatal, and adult skeletal muscle. Loss of Mcu did not affect muscle growth and maturation or otherwise cause pathology. Skeletal muscle-specific deletion of Mcu in mice also did not affect myofiber intracellular Ca2+ handling, but it did inhibit acute mitochondrial Ca2+ influx and mitochondrial respiration stimulated by Ca2+, resulting in reduced acute exercise performance in mice. However, loss of Mcu also resulted in enhanced muscle performance under conditions of fatigue, with a preferential shift toward fatty acid metabolism, resulting in reduced body fat with aging. Together, these results demonstrate that MCU-mediated mitochondrial Ca2+ regulation underlies skeletal muscle fuel selection at baseline and under enhanced physiological demands, which affects total homeostatic metabolism.
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Affiliation(s)
- Jennifer Q Kwong
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.,Department of Pediatrics, Division of Cardiovascular Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jiuzhou Huo
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Michael J Bround
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Justin G Boyer
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Jennifer A Schwanekamp
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Nasab Ghazal
- Department of Pediatrics, Division of Cardiovascular Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Joshua T Maxwell
- Department of Pediatrics, Division of Cardiovascular Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Young C Jang
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Zaza Khuchua
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.,Sechenov University, Moscow, Russia
| | - Kevin Shi
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, California, USA
| | - Jennifer Davis
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Jeffery D Molkentin
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.,Howard Hughes Medical Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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31
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Loro E, Bisetto S, Khurana TS. Mitochondrial ultrastructural adaptations in fast muscles of mice lacking IL15RA. J Cell Sci 2018; 131:jcs.218313. [PMID: 30301784 DOI: 10.1242/jcs.218313] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 10/01/2018] [Indexed: 12/18/2022] Open
Abstract
The pro-inflammatory cytokine interleukin-15 (IL15) and its receptor α (IL15RA) participate in the regulation of musculoskeletal function and metabolism. Deletion of the Il15ra gene in mice increases spontaneous activity, improves fatigue resistance in the glycolytic extensor digitorum longus (EDL) and protects from diet-induced obesity. In humans, IL15RA single-nucleotide polymorphisms (SNPs) have been linked to muscle strength, metabolism and performance in elite endurance athletes. Taken together, these features suggest a possible role for IL15RA in muscle mitochondrial structure and function. Here, we have investigated the consequences of loss of IL15RA on skeletal muscle fiber-type properties and mitochondrial ultrastructure. Immunostaining of the EDL for myosin heavy chain (MyHC) isoforms revealed no significant changes in fiber type. Electron microscopy (EM) analysis of the EDL indicated an overall higher mitochondria content, and increased cristae density in subsarcolemmal and A-band mitochondrial subpopulations. The higher cristae density in Il15ra -/- mitochondria was associated with higher OPA1 and cardiolipin levels. Overall, these data extend our understanding of the role of IL15RA signaling in muscle oxidative metabolism and adaptation to exercise.
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Affiliation(s)
- Emanuele Loro
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sara Bisetto
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Tejvir S Khurana
- Department of Physiology and Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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32
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Kummer S, Wilichowski E. Combination of microdissection and single cell quantitative real-time PCR revealed intercellular mitochondrial DNA heterogeneities in fibroblasts of Kearns-Sayre syndrome patients. Mitochondrion 2018; 43:37-42. [PMID: 30092295 DOI: 10.1016/j.mito.2018.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 07/24/2018] [Accepted: 08/02/2018] [Indexed: 11/26/2022]
Abstract
Kearns-Sayre syndrome (KSS) is a multisystemic disorder marked by aerobic cell metabolism dysfunction. Fibroblasts derived from KSS patient skin biopsy exhibit heterogeneous occurrence of mitochondrial genomes as those circular DNA molecules partially carry the common deletion. In our approach, we aim to evaluate the intercellular alterations in respect to mitochondrial DNA integrity by laser capture microdissection and multiplex quantitative real-time PCR in single cells. The obtained results give new insights into the understanding of mitochondrial genetics, e.g. postulated sorting of damaged mitochondria, and heterogeneity of cells. Further, we discuss the relevance of intercellular heterogeneities for human mitochondrial disorders in general.
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Affiliation(s)
- Susann Kummer
- Mitochondrial Structure and Dynamics, Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
| | - Ekkehard Wilichowski
- Department of Pediatrics and Pediatric Neurology, University Medical Center Göttingen, Georg-August-Universität Göttingen, Göttingen, Germany
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33
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Zorova LD, Popkov VA, Plotnikov EY, Silachev DN, Pevzner IB, Jankauskas SS, Babenko VA, Zorov SD, Balakireva AV, Juhaszova M, Sollott SJ, Zorov DB. Mitochondrial membrane potential. Anal Biochem 2018; 552:50-59. [PMID: 28711444 PMCID: PMC5792320 DOI: 10.1016/j.ab.2017.07.009] [Citation(s) in RCA: 1088] [Impact Index Per Article: 181.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/06/2017] [Accepted: 07/07/2017] [Indexed: 01/13/2023]
Abstract
The mitochondrial membrane potential (ΔΨm) generated by proton pumps (Complexes I, III and IV) is an essential component in the process of energy storage during oxidative phosphorylation. Together with the proton gradient (ΔpH), ΔΨm forms the transmembrane potential of hydrogen ions which is harnessed to make ATP. The levels of ΔΨm and ATP in the cell are kept relatively stable although there are limited fluctuations of both these factors that can occur reflecting normal physiological activity. However, sustained changes in both factors may be deleterious. A long-lasting drop or rise of ΔΨm vs normal levels may induce unwanted loss of cell viability and be a cause of various pathologies. Among other factors, ΔΨm plays a key role in mitochondrial homeostasis through selective elimination of dysfunctional mitochondria. It is also a driving force for transport of ions (other than H+) and proteins which are necessary for healthy mitochondrial functioning. We propose additional potential mechanisms for which ΔΨm is essential for maintenance of cellular health and viability and provide recommendations how to accurately measure ΔΨm in a cell and discuss potential sources of artifacts.
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Affiliation(s)
- Ljubava D Zorova
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation; International Laser Center, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Vasily A Popkov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation; Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Egor Y Plotnikov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Denis N Silachev
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Irina B Pevzner
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Stanislovas S Jankauskas
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Valentina A Babenko
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation; Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Savva D Zorov
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Anastasia V Balakireva
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russian Federation
| | - Magdalena Juhaszova
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Steven J Sollott
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Dmitry B Zorov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation; Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA.
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34
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Lewandowski J, Rozwadowska N, Kolanowski TJ, Malcher A, Zimna A, Rugowska A, Fiedorowicz K, Łabędź W, Kubaszewski Ł, Chojnacka K, Bednarek-Rajewska K, Majewski P, Kurpisz M. The impact of in vitro cell culture duration on the maturation of human cardiomyocytes derived from induced pluripotent stem cells of myogenic origin. Cell Transplant 2018; 27:1047-1067. [PMID: 29947252 PMCID: PMC6158549 DOI: 10.1177/0963689718779346] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Ischemic heart disease, also known as coronary artery disease (CAD), poses a challenge
for regenerative medicine. iPSC technology might lead to a breakthrough due to the
possibility of directed cell differentiation delivering a new powerful source of human
autologous cardiomyocytes. One of the factors supporting proper cell maturation is in
vitro culture duration. In this study, primary human skeletal muscle myoblasts were
selected as a myogenic cell type reservoir for genetic iPSC reprogramming. Skeletal muscle
myoblasts have similar ontogeny embryogenetic pathways (myoblasts vs. cardiomyocytes), and
thus, a greater chance of myocardial development might be expected, with maintenance of
acquired myogenic cardiac cell characteristics, from the differentiation process when
iPSCs of myoblastoid origin are obtained. Analyses of cell morphological and structural
changes, gene expression (cardiac markers), and functional tests (intracellular calcium
transients) performed at two in vitro culture time points spanning the early stages of
cardiac development (day 20 versus 40 of cell in vitro culture) confirmed the ability of
the obtained myogenic cells to acquire adult features of differentiated cardiomyocytes.
Prolonged 40-day iPSC-derived cardiomyocytes (iPSC-CMs) revealed progressive cellular
hypertrophy; a better-developed contractile apparatus; expression of marker genes similar
to human myocardial ventricular cells, including a statistically significant
CX43 increase, an MHC isoform switch, and a troponin I isoform
transition; more efficient intercellular calcium handling; and a stronger response to
β-adrenergic stimulation.
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Affiliation(s)
- Jarosław Lewandowski
- 1 Institute of Human Genetics, Polish Academy of Sciences, Strzeszynska, Poznan, Poland
| | - Natalia Rozwadowska
- 1 Institute of Human Genetics, Polish Academy of Sciences, Strzeszynska, Poznan, Poland
| | - Tomasz J Kolanowski
- 1 Institute of Human Genetics, Polish Academy of Sciences, Strzeszynska, Poznan, Poland
| | - Agnieszka Malcher
- 1 Institute of Human Genetics, Polish Academy of Sciences, Strzeszynska, Poznan, Poland
| | - Agnieszka Zimna
- 1 Institute of Human Genetics, Polish Academy of Sciences, Strzeszynska, Poznan, Poland
| | - Anna Rugowska
- 1 Institute of Human Genetics, Polish Academy of Sciences, Strzeszynska, Poznan, Poland
| | - Katarzyna Fiedorowicz
- 1 Institute of Human Genetics, Polish Academy of Sciences, Strzeszynska, Poznan, Poland
| | - Wojciech Łabędź
- 2 Department of Orthopaedics and Traumatology, W. Dega University Hospital, Poznan University of Medical Sciences, Poznan, Poland.,3 Department of Spondyloorthopaedics and Biomechanics of the Spine, W. Dega University Hospital, Poznan University of Medical Sciences, Poznan, Poland
| | - Łukasz Kubaszewski
- 2 Department of Orthopaedics and Traumatology, W. Dega University Hospital, Poznan University of Medical Sciences, Poznan, Poland.,3 Department of Spondyloorthopaedics and Biomechanics of the Spine, W. Dega University Hospital, Poznan University of Medical Sciences, Poznan, Poland
| | - Katarzyna Chojnacka
- 4 Department of Clinical Pathology, Heliodor Swiecicki Clinical Hospital No. 2 of the Poznan University of Medical Sciences, Poznan, Poland
| | | | - Przemysław Majewski
- 5 Department of Clinical Pathology, Poznan University of Medical Sciences, Poznan, Poland
| | - Maciej Kurpisz
- 1 Institute of Human Genetics, Polish Academy of Sciences, Strzeszynska, Poznan, Poland
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35
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Barrasso AP, Tong X, Poché RA. The mito::mKate2 mouse: A far-red fluorescent reporter mouse line for tracking mitochondrial dynamics in vivo. Genesis 2018; 56:10.1002/dvg.23087. [PMID: 29243279 PMCID: PMC5818295 DOI: 10.1002/dvg.23087] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/30/2017] [Accepted: 12/12/2017] [Indexed: 12/31/2022]
Abstract
Mitochondria are incredibly dynamic organelles that undergo continuous fission and fusion events to control morphology, which profoundly impacts cell physiology including cell cycle progression. This is highlighted by the fact that most major human neurodegenerative diseases are due to specific disruptions in mitochondrial fission or fusion machinery and null alleles of these genes result in embryonic lethality. To gain a better understanding of the pathophysiology of such disorders, tools for the in vivo assessment of mitochondrial dynamics are required. It would be particularly advantageous to simultaneously image mitochondrial fission-fusion coincident with cell cycle progression. To that end, we have generated a new transgenic reporter mouse, called mito::mKate2 that ubiquitously expresses a mitochondria localized far-red mKate2 fluorescent protein. Here we show that mito::mKate2 mice are viable and fertile and that mKate2 fluorescence can be spectrally separated from the previously developed Fucci cell cycle reporters. By crossing mito::mKate2 mice to the ROSA26R-mTmG dual fluorescent Cre reporter line, we also demonstrate the potential utility of mito::mKate2 for genetic mosaic analysis of mitochondrial phenotypes.
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Affiliation(s)
- Anthony P. Barrasso
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
- Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xuefei Tong
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ross A. Poché
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX 77030, USA
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36
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Chapa-Dubocq X, Makarov V, Javadov S. Simple kinetic model of mitochondrial swelling in cardiac cells. J Cell Physiol 2018; 233:5310-5321. [PMID: 29215716 DOI: 10.1002/jcp.26335] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/27/2017] [Indexed: 12/12/2022]
Abstract
Mitochondria play an important role in both cell survival and cell death. In response to oxidative stress, they undergo opening of non-selective permeability transition pores (PTP) in the inner mitochondrial membrane. Sustained PTP opening triggers mitochondrial swelling due to increased colloidal osmotic pressure in the matrix accompanied by mitochondrial membrane depolarization and ATP hydrolysis. Mitochondrial swelling is the major factor leading to mitochondria-mediated cell death through both apoptosis and necrosis. Hence, precise estimation of the threshold parameters of the transition of reversible swelling to irreversible swelling is important for understanding the mechanisms of PTP-mediated cell death as well as for the development of new therapeutic approaches targeting the mitochondria under pathological conditions. In this study, we designed a simple kinetic model of the Ca2+ -induced mitochondrial swelling that describes the mechanisms of transition from reversible to irreversible swelling in cardiac mitochondria. Values of kinetic parameters calculated using parameter estimation techniques that fit experimental data of mitochondrial swelling with minimum average differences between the experimental data and model parameters. Overall, this study provides a kinetic model verified by data simulation and model fitting that adequately describes the dynamics of mitochondrial swelling.
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Affiliation(s)
- Xavier Chapa-Dubocq
- Department of Physiology and Biophysics, Medical Sciences Campus University of Puerto Rico, San Juan, Puerto Rico
| | - Vladimir Makarov
- Department of Physics, University of Puerto Rico Rio Piedras Campus, San Juan, Puerto Rico
| | - Sabzali Javadov
- Department of Physiology and Biophysics, Medical Sciences Campus University of Puerto Rico, San Juan, Puerto Rico
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37
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Javadov S, Jang S, Parodi-Rullán R, Khuchua Z, Kuznetsov AV. Mitochondrial permeability transition in cardiac ischemia-reperfusion: whether cyclophilin D is a viable target for cardioprotection? Cell Mol Life Sci 2017; 74:2795-2813. [PMID: 28378042 PMCID: PMC5977999 DOI: 10.1007/s00018-017-2502-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 02/28/2017] [Accepted: 03/06/2017] [Indexed: 12/13/2022]
Abstract
Growing number of studies provide strong evidence that the mitochondrial permeability transition pore (PTP), a non-selective channel in the inner mitochondrial membrane, is involved in the pathogenesis of cardiac ischemia-reperfusion and can be targeted to attenuate reperfusion-induced damage to the myocardium. The molecular identity of the PTP remains unknown and cyclophilin D is the only protein commonly accepted as a major regulator of the PTP opening. Therefore, cyclophilin D is an attractive target for pharmacological or genetic therapies to reduce ischemia-reperfusion injury in various animal models and humans. Most animal studies demonstrated cardioprotective effects of PTP inhibition; however, a recent large clinical trial conducted by international groups demonstrated that cyclosporine A, a cyclophilin D inhibitor, failed to protect the heart in patients with myocardial infarction. These studies, among others, raise the question of whether cyclophilin D, which plays an important physiological role in the regulation of cell metabolism and mitochondrial bioenergetics, is a viable target for cardioprotection. This review discusses previous studies to provide comprehensive information on the physiological role of cyclophilin D as well as PTP opening in the cell that can be taken into consideration for the development of new PTP inhibitors.
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Affiliation(s)
- Sabzali Javadov
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, PR 00936-5067, Puerto Rico.
| | - Sehwan Jang
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, PR 00936-5067, Puerto Rico
| | - Rebecca Parodi-Rullán
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, PR 00936-5067, Puerto Rico
| | - Zaza Khuchua
- Cincinnati Children's Research Foundation, University of Cincinnati, 240 Albert Sabin Way, Cincinnati, OH, 54229, USA
| | - Andrey V Kuznetsov
- Cardiac Surgery Research Laboratory, Department of Cardiac Surgery, Innsbruck Medical University, Innsbruck, Austria
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Mitochondrial Heterogeneity: Evaluating Mitochondrial Subpopulation Dynamics in Stem Cells. Stem Cells Int 2017; 2017:7068567. [PMID: 28757879 PMCID: PMC5516713 DOI: 10.1155/2017/7068567] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 05/03/2017] [Indexed: 01/29/2023] Open
Abstract
Although traditionally viewed as the “powerhouse” of the cell, an accruing body of evidence in the rapidly growing field of mitochondrial biology supports additional roles of mitochondria as key participants in a multitude of cellular functions. While it has been well established that mitochondria in different tissues have distinctive ultrastructural features consistent with differential bioenergetic demands, recent and emerging technical advances in flow cytometry, imaging, and “-omics”-based bioinformatics have only just begun to explore the complex and divergent properties of mitochondria within tissues and cell types. Moreover, contemporary studies evaluating the role of mitochondria in pluripotent stem cells, cellular reprogramming, and differentiation point to a potential importance of mitochondrial subpopulations and heterogeneity in the field of stem cell biology. This review assesses the current literature regarding mitochondrial subpopulations within cell and tissue types and evaluates the current understanding of how mitochondrial diversity and heterogeneity might impact cell fate specification in pluripotent stem cells.
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39
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MacDonald JA, Fowle WH, Woods PhD DC. New insights on mitochondrial heterogeneity observed in prepared mitochondrial samples following a method for freeze-fracture and scanning electron microscopy. Micron 2017; 101:25-31. [PMID: 28609725 DOI: 10.1016/j.micron.2017.05.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/02/2017] [Accepted: 05/02/2017] [Indexed: 10/19/2022]
Abstract
Mitochondria are dynamic intracellular organelles with diverse roles in tissue- and cell type-specific processes, extending beyond bioenergetics. In keeping with this array of functions, mitochondria are described as heterogeneous both between and within tissue types based on multiple parameters, including a broad spectrum of morphological features, and new research points toward a need for the evaluation of mitochondria as isolated organelles. Although transmission electron microscopy (TEM) is commonly used for the evaluation of mitochondria in tissues and renders mitochondrial structures in ultra-thin sections in two-dimensions, additional information regarding complex features within these organelles can be ascertained using scanning electron microscopy (SEM), which allows for analysis of phenotypic differences in three-dimensions. One challenge in producing mitochondrial images for evaluation of ultrastructure using SEM has been the ability to reliably visualize important intramitochondrial features, the inner membrane and cristae structures, on a large-scale (e.g. multiple mitochondria) within a sample preparation, as mitochondria are enclosed within a double membrane. This can be overcome using a 'freeze-fracture' technique in which mitochondrial preparations are snap-frozen followed by application of intense pressure to break open the organelles, revealing the intact components within. Previously published reports using freeze-fracture strategies for mitochondrial SEM have demonstrated feasibility in whole tissue specimens, but a detailed methodology for SEM analysis on isolated mitochondrial fractions has not been reported. By combining previously reported tissue freeze-fracture strategies, along with utilizing the depth of field created by SEM, herein we present a complete method reliant on the freeze-fracture of mitochondrial fractions prepared by differential centrifugation to produce a comprehensive and direct evaluation of three-dimensional mitochondrial ultrastructure by SEM. Image analysis of internal mitochondrial features demonstrates heterogeneity in mitochondrial ultrastructure from a single sample preparation.
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Affiliation(s)
- Julie A MacDonald
- Department of Biology, Northeastern University, Boston, MA, 02115, USA
| | - William H Fowle
- Department of Biology, Northeastern University, Boston, MA, 02115, USA
| | - Dori C Woods PhD
- Department of Biology, Northeastern University, Boston, MA, 02115, USA.
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Thomas LW, Staples O, Turmaine M, Ashcroft M. CHCHD4 Regulates Intracellular Oxygenation and Perinuclear Distribution of Mitochondria. Front Oncol 2017; 7:71. [PMID: 28497026 PMCID: PMC5406405 DOI: 10.3389/fonc.2017.00071] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 03/28/2017] [Indexed: 11/25/2022] Open
Abstract
Hypoxia is a characteristic of the tumor microenvironment and is known to contribute to tumor progression and treatment resistance. Hypoxia-inducible factor (HIF) dimeric transcription factors control the cellular response to reduced oxygenation by regulating the expression of genes involved in metabolic adaptation, cell motility, and survival. Alterations in mitochondrial metabolism are not only a downstream consequence of HIF-signaling but mitochondria reciprocally regulate HIF signaling through multiple means, including oxygen consumption, metabolic intermediates, and reactive oxygen species generation. CHCHD4 is a redox-sensitive mitochondrial protein, which we previously identified and showed to be a novel regulator of HIF and hypoxia responses in tumors. Elevated expression of CHCHD4 in human tumors correlates with the hypoxia gene signature, disease progression, and poor patient survival. Here, we show that either long-term (72 h) exposure to hypoxia (1% O2) or elevated expression of CHCHD4 in tumor cells in normoxia leads to perinuclear accumulation of mitochondria, which is dependent on the expression of HIF-1α. Furthermore, we show that CHCHD4 is required for perinuclear localization of mitochondria and HIF activation in response to long-term hypoxia. Mutation of the functionally important highly conserved cysteines within the Cys-Pro-Cys motif of CHCHD4 or inhibition of complex IV activity (by sodium azide) redistributes mitochondria from the perinuclear region toward the periphery of the cell and blocks HIF activation. Finally, we show that CHCHD4-mediated perinuclear localization of mitochondria is associated with increased intracellular hypoxia within the perinuclear region and constitutive basal HIF activation in normoxia. Our study demonstrates that the intracellular distribution of the mitochondrial network is an important feature of the cellular response to hypoxia, contributing to hypoxic signaling via HIF activation and regulated by way of the cross talk between CHCHD4 and HIF-1α.
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Affiliation(s)
- Luke W. Thomas
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Oliver Staples
- Centre for Cell Signalling and Molecular Genetics, Division of Medicine, University College London, London, UK
| | - Mark Turmaine
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Margaret Ashcroft
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
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Kuznetsov AV, Javadov S, Saks V, Margreiter R, Grimm M. Synchronism in mitochondrial ROS flashes, membrane depolarization and calcium sparks in human carcinoma cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:418-431. [PMID: 28279675 DOI: 10.1016/j.bbabio.2017.03.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/09/2017] [Accepted: 03/02/2017] [Indexed: 02/02/2023]
Abstract
Mitochondria are major producers of reactive oxygen species (ROS) in many cells including cancer cells. However, complex interrelationships between mitochondrial ROS (mitoROS), mitochondrial membrane potential (ΔΨm) and Ca2+ are not completely understood. Using human carcinoma cells, we further highlight biphasic ROS dynamics: - gradual mitoROS increase followed by mitoROS flash. Also, we demonstrate heterogeneity in rates of mitoROS generation and flash initiation time. Comparing mitochondrial and near-extra-mitochondrial signals, we show that mechanisms of mitoROS flashes in single mitochondria, linked to mitochondrial permeability transition pore opening (ΔΨm collapse) and calcium sparks, may involve flash triggering by certain levels of external ROS released from the same mitochondria. In addition, mitochondria-mitochondria interactions can produce wave propagations of mitoROS flashes and ΔΨm collapses in cancer cells similar to phenomena of ROS-induced ROS release (RIRR). Our data suggest that in cancer cells RIRR, activation of mitoROS flashes and mitochondrial depolarization may involve participation of extramitochondrial-ROS produced either by individual mitochondria and/or by neighboring mitochondria. This could represent general mechanisms in ROS-ROS signaling with suggested role in both mitochondrial and cellular physiology and signaling.
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Affiliation(s)
- Andrey V Kuznetsov
- Cardiac Surgery Laboratory, Department of Heart Surgery, Medical University of Innsbruck, Innsbruck A-6020, Austria.
| | - Sabzali Javadov
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, PR 00936-5067, USA
| | - Valdur Saks
- Laboratory of Fundamental and Applied Bioenergetics, INSERM U884, University Joseph Fourier, Grenoble, France
| | - Raimund Margreiter
- Department of Visceral, Transplant and Thoracic Surgery, Medical University of Innsbruck, Innsbruck, Austria
| | - Michael Grimm
- Cardiac Surgery Laboratory, Department of Heart Surgery, Medical University of Innsbruck, Innsbruck A-6020, Austria
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42
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Nürnberger S, Rentenberger C, Thiel K, Schädl B, Grunwald I, Ponomarev I, Marlovits S, Meyer C, Barnewitz D. Giant crystals inside mitochondria of equine chondrocytes. Histochem Cell Biol 2016; 147:635-649. [PMID: 28013370 PMCID: PMC5400799 DOI: 10.1007/s00418-016-1516-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2016] [Indexed: 01/20/2023]
Abstract
The present study reports for the first time the presence of giant crystals in mitochondria of equine chondrocytes. These structures show dark contrast in TEM images as well as a granular substructure of regularly aligned 1-2 nm small units. Different zone axes of the crystalline structure were analysed by means of Fourier transformation of lattice-resolution TEM images proving the crystalline nature of the structure. Elemental analysis reveals a high content of nitrogen referring to protein. The outer shape of the crystals is geometrical with an up to hexagonal profile in cross sections. It is elongated, spanning a length of several micrometres through the whole cell. In some chondrocytes, several crystals were found, sometimes combined in a single mitochondrion. Crystals were preferentially aligned along the long axis of the cells, thus appearing in the same orientation as the chondrocytes in the tissue. Although no similar structures have been found in the cartilage of any other species investigated, they have been found in cartilage repair tissue formed within a mechanically stimulated equine chondrocyte construct. Crystals were mainly located in superficial regions of cartilage, especially in joint regions of well-developed superficial layers, more often in yearlings than in adult horses. These results indicate that intramitochondrial crystals are related to the high mechanical stress in the horse joint and potentially also to the increased metabolic activity of immature individuals.
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Affiliation(s)
- S Nürnberger
- Department of Trauma Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria. .,Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, Donaueschingenstrasse 13, 1200, Vienna, Austria. .,University Clinic of Dentistry, Medical University of Vienna, Sensengasse 2a, 1090, Vienna, Austria. .,Austrian Cluster for Tissue Regeneration, Vienna, Austria.
| | - C Rentenberger
- Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
| | - K Thiel
- Department of Adhesive Bonding Technology and Surfaces, Fraunhofer Institute for Manufacturing Technology and Advanced Materials, Wiener Strasse 12, 28359 Bremen, Germany
| | - B Schädl
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, Donaueschingenstrasse 13, 1200, Vienna, Austria.,University Clinic of Dentistry, Medical University of Vienna, Sensengasse 2a, 1090, Vienna, Austria.,Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - I Grunwald
- Department of Adhesive Bonding Technology and Surfaces, Fraunhofer Institute for Manufacturing Technology and Advanced Materials, Wiener Strasse 12, 28359 Bremen, Germany
| | - I Ponomarev
- Research Centre for Medical Technics and Biotechnology, Geranienweg 7, 99947, Bad Langensalza, Germany
| | - St Marlovits
- Department of Trauma Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.,Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Ch Meyer
- Clinic and Polyclinic for Traumatology, University of Giessen, Rudolf-Buchheim-Straße 7, 35385, Giessen, Germany.,Orthopaedic and Trauma Surgery, Klinikum Saarbrücken, Winterberg 1, 66119, Saarbrücken, Germany
| | - D Barnewitz
- Research Centre for Medical Technics and Biotechnology, Geranienweg 7, 99947, Bad Langensalza, Germany
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43
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Galan DT, Bito V, Claus P, Holemans P, Abi-Char J, Nagaraju CK, Dries E, Vermeulen K, Ventura-Clapier R, Sipido KR, Driesen RB. Reduced mitochondrial respiration in the ischemic as well as in the remote nonischemic region in postmyocardial infarction remodeling. Am J Physiol Heart Circ Physiol 2016; 311:H1075-H1090. [PMID: 27614227 DOI: 10.1152/ajpheart.00945.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 08/07/2016] [Indexed: 11/22/2022]
Abstract
Scarring and remodeling of the left ventricle (LV) after myocardial infarction (MI) results in ischemic cardiomyopathy with reduced contractile function. Regional differences related to persisting ischemia may exist. We investigated the hypothesis that mitochondrial function and structure is altered in the myocardium adjacent to MI with reduced perfusion (MIadjacent) and less so in the remote, nonischemic myocardium (MIremote). We used a pig model of chronic coronary stenosis and MI (n = 13). Functional and perfusion MR imaging 6 wk after intervention showed reduced ejection fraction and increased global wall stress compared with sham-operated animals (Sham; n = 14). Regional strain in MIadjacent was reduced with reduced contractile reserve; in MIremote strain was also reduced but responsive to dobutamine and perfusion was normal compared with Sham. Capillary density was unchanged. Cardiac myocytes isolated from both regions had reduced basal and maximal oxygen consumption rate, as well as through complex I and II, but complex IV activity was unchanged. Reduced respiration was not associated with detectable reduction of mitochondrial density. There was no significant change in AMPK or glucose transporter expression levels, but glycogen content was significantly increased in both MIadjacent and MIremote Glycogen accumulation was predominantly perinuclear; mitochondria in this area were smaller but only in MIadjacent where also subsarcolemmal mitochondria were smaller. In conclusion, after MI reduction of mitochondrial respiration and glycogen accumulation occur in all LV regions suggesting that reduced perfusion does not lead to additional specific changes and that increased hemodynamic load is the major driver for changes in mitochondrial function.
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Affiliation(s)
- Diogo T Galan
- Division of Experimental Cardiology, KU Leuven, University of Leuven, Leuven, Belgium
| | - Virginie Bito
- Division of Experimental Cardiology, KU Leuven, University of Leuven, Leuven, Belgium
| | - Piet Claus
- Cardiovascular Imaging and Dynamics, Department of Cardiovascular Sciences, KU Leuven, University of Leuven, Leuven, Belgium; and
| | - Patricia Holemans
- Division of Experimental Cardiology, KU Leuven, University of Leuven, Leuven, Belgium
| | - Joëlle Abi-Char
- Division of Experimental Cardiology, KU Leuven, University of Leuven, Leuven, Belgium
| | - Chandan K Nagaraju
- Division of Experimental Cardiology, KU Leuven, University of Leuven, Leuven, Belgium
| | - Eef Dries
- Division of Experimental Cardiology, KU Leuven, University of Leuven, Leuven, Belgium
| | - Kristel Vermeulen
- Division of Experimental Cardiology, KU Leuven, University of Leuven, Leuven, Belgium
| | | | - Karin R Sipido
- Division of Experimental Cardiology, KU Leuven, University of Leuven, Leuven, Belgium;
| | - Ronald B Driesen
- Division of Experimental Cardiology, KU Leuven, University of Leuven, Leuven, Belgium
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44
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Exercise Promotes Healthy Aging of Skeletal Muscle. Cell Metab 2016; 23:1034-1047. [PMID: 27304505 PMCID: PMC5045036 DOI: 10.1016/j.cmet.2016.05.007] [Citation(s) in RCA: 292] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 05/18/2016] [Accepted: 05/24/2016] [Indexed: 02/08/2023]
Abstract
Primary aging is the progressive and inevitable process of bodily deterioration during adulthood. In skeletal muscle, primary aging causes defective mitochondrial energetics and reduced muscle mass. Secondary aging refers to additional deleterious structural and functional age-related changes caused by diseases and lifestyle factors. Secondary aging can exacerbate deficits in mitochondrial function and muscle mass, concomitant with the development of skeletal muscle insulin resistance. Exercise opposes deleterious effects of secondary aging by preventing the decline in mitochondrial respiration, mitigating aging-related loss of muscle mass and enhancing insulin sensitivity. This review focuses on mechanisms by which exercise promotes "healthy aging" by inducing modifications in skeletal muscle.
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45
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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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46
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Hatano A, Okada JI, Washio T, Hisada T, Sugiura S. Distinct functional roles of cardiac mitochondrial subpopulations revealed by a 3D simulation model. Biophys J 2016; 108:2732-9. [PMID: 26039174 DOI: 10.1016/j.bpj.2015.04.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 04/08/2015] [Accepted: 04/21/2015] [Indexed: 10/23/2022] Open
Abstract
Experimental characterization of two cardiac mitochondrial subpopulations, namely, subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM), has been hampered by technical difficulties, and an alternative approach is eagerly awaited. We previously developed a three-dimensional computational cardiomyocyte model that integrates electrophysiology, metabolism, and mechanics with subcellular structure. In this study, we further developed our model to include intracellular oxygen diffusion, and determined whether mitochondrial localization or intrinsic properties cause functional variations. For this purpose, we created two models: one with equal SSM and IFM properties and one with IFM having higher activity levels. Using these two models to compare the SSM and IFM responses of [Ca(2+)], tricarboxylic acid cycle activity, [NADH], and mitochondrial inner membrane potential to abrupt changes in pacing frequency (0.25-2 Hz), we found that the reported functional differences between these subpopulations appear to be mostly related to local [Ca(2+)] heterogeneity, and variations in intrinsic properties only serve to augment these differences. We also examined the effect of hypoxia on mitochondrial function. Under normoxic conditions, intracellular oxygen is much higher throughout the cell than the half-saturation concentration for oxidative phosphorylation. However, under limited oxygen supply, oxygen is mostly exhausted in SSM, leaving the core region in an anoxic condition. Reflecting this heterogeneous oxygen environment, the inner membrane potential continues to decrease in IFM, whereas it is maintained to nearly normal levels in SSM, thereby ensuring ATP supply to this region. Our simulation results provide clues to understanding the origin of functional variations in two cardiac mitochondrial subpopulations and their differential roles in maintaining cardiomyocyte function as a whole.
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Affiliation(s)
- Asuka Hatano
- Department of Mechanical Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan.
| | - Jun-Ichi Okada
- Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Takumi Washio
- Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Toshiaki Hisada
- Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Seiryo Sugiura
- Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
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47
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Ashraf MI, Fries D, Streif W, Aigner F, Hengster P, Troppmair J, Hermann M. Biopsychronology: A Method Using Live Tissue Staining to Image Cell Function in the Kidney. Methods Mol Biol 2016; 1397:81-90. [PMID: 26676129 DOI: 10.1007/978-1-4939-3353-2_8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Methods to monitor the status of a graft prior to transplantation are highly desirable to avoid unnecessary surgical interventions and follow-up treatments and to optimize the clinical outcome as delayed graft function may lead to costly and lengthy follow-up treatments or even organ loss. As a promising step in this direction we present a method which combines the use of fine needle biopsies, the staining of living cells with dyes suitable to monitor mitochondrial status/cellular integrity, and live confocal real-time analysis.This approach provides information about the functional and structural intactness of an organ within a few minutes. To confirm the feasibility of this approach, we recently published a pilot study using rodent kidneys. The results demonstrated that this method is suitable to monitor organ damage caused by ischemia or short periods of reperfusion. This procedure required minimal time for sample preparation and data acquisition and is suitable for recording damage resulting from unphysiological stress to the organ.
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Affiliation(s)
- Muhammad Imtiaz Ashraf
- Daniel Swarovski Research Laboratory, Department of Visceral, Transplant and Thoracic Surgery, Center of Operative Medicine, Medical University Innsbruck, Innsbruck, Austria
| | - Dietmar Fries
- Department of General and Surgical Critical Care Medicine, Medical University Innsbruck, Innsbruck, Austria
| | - Werner Streif
- Department of Pediatrics I, Medical University Innsbruck, Innsbruck, Austria
| | - Felix Aigner
- Daniel Swarovski Research Laboratory, Department of Visceral, Transplant and Thoracic Surgery, Center of Operative Medicine, Medical University Innsbruck, Innsbruck, Austria
| | - Paul Hengster
- Daniel Swarovski Research Laboratory, Department of Visceral, Transplant and Thoracic Surgery, Center of Operative Medicine, Medical University Innsbruck, Innsbruck, Austria
| | - Jakob Troppmair
- Daniel Swarovski Research Laboratory, Department of Visceral, Transplant and Thoracic Surgery, Center of Operative Medicine, Medical University Innsbruck, Innsbruck, Austria
| | - Martin Hermann
- Department of General and Surgical Critical Care Medicine, Medical University Innsbruck, Innsbruck, Austria. .,Department of Anesthesiology and Critical Care Medicine, Medical University Innsbruck, Innsbruck, Austria.
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48
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HS-543 induces apoptosis of Imatinib-resistant chronic myelogenous leukemia with T315I mutation. Oncotarget 2015; 6:1507-18. [PMID: 25483100 PMCID: PMC4359310 DOI: 10.18632/oncotarget.2837] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 12/01/2014] [Indexed: 11/25/2022] Open
Abstract
Chronic myeloid leukemia (CML) is characterized by a constitutive activation of Bcr-Abl tyrosine kinase. Bcr-Abl/T315I is the predominant mutation that causes resistance to Imatinib. In the present study, we synthesized a novel Bcr-Abl inhibitor, HS-543, and investigated its effect on cell survival or apoptosis in CML cells bearing Bcr-Abl/T315I (BaF3/T315I) or wild-type Bcr-Abl (BaF3/WT). HS-543 showed anti-proliferative effects in the BaF3/WT cells as well as the BaF3/T315I cells with resistance to Imatinib and strongly inhibited the Bcr-Abl signaling pathway in a dose-dependent manner. Furthermore, it significantly increased the sub G1 phase associated with early apoptosis, with increased levels of cleaved PARP and cleaved caspase-3, as well as the TUNEL-positive apoptotic cells. In addition, we found that HS-543 induced apoptosis with the loss of mitochondrial membrane potential by decreasing the expression of Mcl-1 and survivin, together with increasing that of Bax. In BaF3/T315I xenograft models, HS-543 significantly delayed tumor growth, unlike Imatinib. Our results demonstrate that HS-543 exhibits the induction of apoptosis and anti-proliferative effect by blocking the Bcr-Abl signaling pathway in the T315I-mutated Bcr-Abl cells with resistance to Imatinib. We suggest that HS-543 may be a novel promising agent to target Bcr-Abl and overcome Imatinib resistance in CML patients.
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49
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Nichols CE, Shepherd DL, Knuckles TL, Thapa D, Stricker JC, Stapleton PA, Minarchick VC, Erdely A, Zeidler-Erdely PC, Alway SE, Nurkiewicz TR, Hollander JM. Cardiac and mitochondrial dysfunction following acute pulmonary exposure to mountaintop removal mining particulate matter. Am J Physiol Heart Circ Physiol 2015; 309:H2017-30. [PMID: 26497962 DOI: 10.1152/ajpheart.00353.2015] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 10/05/2015] [Indexed: 01/29/2023]
Abstract
Throughout the United States, air pollution correlates with adverse health outcomes, and cardiovascular disease incidence is commonly increased following environmental exposure. In areas surrounding active mountaintop removal mines (MTM), a further increase in cardiovascular morbidity is observed and may be attributed in part to particulate matter (PM) released from the mine. The mitochondrion has been shown to be central in the etiology of many cardiovascular diseases, yet its roles in PM-related cardiovascular effects are not realized. In this study, we sought to elucidate the cardiac processes that are disrupted following exposure to mountaintop removal mining particulate matter (PM MTM). To address this question, we exposed male Sprague-Dawley rats to PM MTM, collected within one mile of an active MTM site, using intratracheal instillation. Twenty-four hours following exposure, we evaluated cardiac function, apoptotic indices, and mitochondrial function. PM MTM exposure elicited a significant decrease in ejection fraction and fractional shortening compared with controls. Investigation into the cellular impacts of PM MTM exposure identified a significant increase in mitochondrial-induced apoptotic signaling, as reflected by an increase in TUNEL-positive nuclei and increased caspase-3 and -9 activities. Finally, a significant increase in mitochondrial transition pore opening leading to decreased mitochondrial function was identified following exposure. In conclusion, our data suggest that pulmonary exposure to PM MTM increases cardiac mitochondrial-associated apoptotic signaling and decreases mitochondrial function concomitant with decreased cardiac function. These results suggest that increased cardiovascular disease incidence in populations surrounding MTM mines may be associated with increased cardiac cell apoptotic signaling and decreased mitochondrial function.
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Affiliation(s)
- Cody E Nichols
- West Virginia University School of Medicine, Division of Exercise Physiology, Morgantown, West Virginia; Center for Cardiovascular and Respiratory Sciences, Morgantown, West Virginia
| | - Danielle L Shepherd
- West Virginia University School of Medicine, Division of Exercise Physiology, Morgantown, West Virginia; Center for Cardiovascular and Respiratory Sciences, Morgantown, West Virginia
| | - Travis L Knuckles
- Center for Cardiovascular and Respiratory Sciences, Morgantown, West Virginia; West Virginia University, School of Public Health, Morgantown, West Virginia
| | - Dharendra Thapa
- West Virginia University School of Medicine, Division of Exercise Physiology, Morgantown, West Virginia; Center for Cardiovascular and Respiratory Sciences, Morgantown, West Virginia
| | - Janelle C Stricker
- Center for Cardiovascular and Respiratory Sciences, Morgantown, West Virginia
| | - Phoebe A Stapleton
- Center for Cardiovascular and Respiratory Sciences, Morgantown, West Virginia; West Virginia University, Department of Physiology and Pharmacology, Morgantown, West Virginia
| | - Valerie C Minarchick
- Center for Cardiovascular and Respiratory Sciences, Morgantown, West Virginia; West Virginia University, Department of Physiology and Pharmacology, Morgantown, West Virginia
| | - Aaron Erdely
- West Virginia University, Department of Physiology and Pharmacology, Morgantown, West Virginia; National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - Patti C Zeidler-Erdely
- West Virginia University, Department of Physiology and Pharmacology, Morgantown, West Virginia; National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - Stephen E Alway
- West Virginia University School of Medicine, Division of Exercise Physiology, Morgantown, West Virginia; Center for Cardiovascular and Respiratory Sciences, Morgantown, West Virginia
| | - Timothy R Nurkiewicz
- Center for Cardiovascular and Respiratory Sciences, Morgantown, West Virginia; West Virginia University, Department of Physiology and Pharmacology, Morgantown, West Virginia
| | - John M Hollander
- West Virginia University School of Medicine, Division of Exercise Physiology, Morgantown, West Virginia; Center for Cardiovascular and Respiratory Sciences, Morgantown, West Virginia;
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50
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Mourier A, Motori E, Brandt T, Lagouge M, Atanassov I, Galinier A, Rappl G, Brodesser S, Hultenby K, Dieterich C, Larsson NG. Mitofusin 2 is required to maintain mitochondrial coenzyme Q levels. ACTA ACUST UNITED AC 2015; 208:429-42. [PMID: 25688136 PMCID: PMC4332246 DOI: 10.1083/jcb.201411100] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Mitofusin 2 plays an unexpected role in maintaining the terpenoid biosynthesis pathway and is necessary for mitochondrial coenzyme Q biosynthesis. Mitochondria form a dynamic network within the cell as a result of balanced fusion and fission. Despite the established role of mitofusins (MFN1 and MFN2) in mitochondrial fusion, only MFN2 has been associated with metabolic and neurodegenerative diseases, which suggests that MFN2 is needed to maintain mitochondrial energy metabolism. The molecular basis for the mitochondrial dysfunction encountered in the absence of MFN2 is not understood. Here we show that loss of MFN2 leads to impaired mitochondrial respiration and reduced ATP production, and that this defective oxidative phosphorylation process unexpectedly originates from a depletion of the mitochondrial coenzyme Q pool. Our study unravels an unexpected and novel role for MFN2 in maintenance of the terpenoid biosynthesis pathway, which is necessary for mitochondrial coenzyme Q biosynthesis. The reduced respiratory chain function in cells lacking MFN2 can be partially rescued by coenzyme Q10 supplementation, which suggests a possible therapeutic strategy for patients with diseases caused by mutations in the Mfn2 gene.
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Affiliation(s)
- Arnaud Mourier
- Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Elisa Motori
- Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Tobias Brandt
- Max Planck Institute of Biophysics, 60438 Frankfurt, Germany
| | - Marie Lagouge
- Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Ilian Atanassov
- Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Anne Galinier
- STROMALab, UMR Université Paul Sabatier/Centre National de la Recherche Scientifique 5273, Institut National de la Santé et de la Recherche Médicale U1031, BP 84 225-F-31 432, Toulouse, France
| | - Gunter Rappl
- Department I of Internal Medicine, University Hospital Cologne, and Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany Department I of Internal Medicine, University Hospital Cologne, and Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Susanne Brodesser
- CECAD Research Center, Lipidomics Facility, University of Cologne, 50931 Cologne, Germany
| | - Kjell Hultenby
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | - Nils-Göran Larsson
- Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
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