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Desai S, Grefte S, van de Westerlo E, Lauwen S, Paters A, Prehn JHM, Gan Z, Keijer J, Adjobo-Hermans MJW, Koopman WJH. Performance of TMRM and Mitotrackers in mitochondrial morphofunctional analysis of primary human skin fibroblasts. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149027. [PMID: 38109971 DOI: 10.1016/j.bbabio.2023.149027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 10/30/2023] [Accepted: 12/04/2023] [Indexed: 12/20/2023]
Abstract
Mitochondrial membrane potential (Δψ) and morphology are considered key readouts of mitochondrial functional state. This morphofunction can be studied using fluorescent dyes ("probes") like tetramethylrhodamine methyl ester (TMRM) and Mitotrackers (MTs). Although these dyes are broadly used, information comparing their performance in mitochondrial morphology quantification and Δψ-sensitivity in the same cell model is still scarce. Here we applied epifluorescence microscopy of primary human skin fibroblasts to evaluate TMRM, Mitotracker Red CMXros (CMXros), Mitotracker Red CMH2Xros (CMH2Xros), Mitotracker Green FM (MG) and Mitotracker Deep Red FM (MDR). All probes were suited for automated quantification of mitochondrial morphology parameters when Δψ was normal, although they did not deliver quantitatively identical results. The mitochondrial localization of TMRM and MTs was differentially sensitive to carbonyl cyanide-4-phenylhydrazone (FCCP)-induced Δψ depolarization, decreasing in the order: TMRM ≫ CHM2Xros = CMXros = MDR > MG. To study the effect of reversible Δψ changes, the impact of photo-induced Δψ "flickering" was studied in cells co-stained with TMRM and MG. During a flickering event, individual mitochondria displayed subsequent TMRM release and uptake, whereas this phenomenon was not observed for MG. Spatiotemporal and computational analysis of the flickering event provided evidence that TMRM redistributes between adjacent mitochondria by a mechanism dependent on Δψ and TMRM concentration. In summary, this study demonstrates that: (1) TMRM and MTs are suited for automated mitochondrial morphology quantification, (2) numerical data obtained with different probes is not identical, and (3) all probes are sensitive to FCCP-induced Δψ depolarization, with TMRM and MG displaying the highest and lowest sensitivity, respectively. We conclude that TMRM is better suited for integrated analysis of Δψ and mitochondrial morphology than the tested MTs under conditions that Δψ is not substantially depolarized.
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Affiliation(s)
- Shruti Desai
- Department of Medical BioSciences, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Sander Grefte
- Department of Physiology and Medical Physics and SFI FutureNeuro Centre, RCSI University of Medicine and Health Sciences, Dublin 2, Ireland
| | - Els van de Westerlo
- Department of Medical BioSciences, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Susette Lauwen
- Department of Medical BioSciences, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Angela Paters
- Department of Medical BioSciences, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Jochen H M Prehn
- Department of Physiology and Medical Physics and SFI FutureNeuro Centre, RCSI University of Medicine and Health Sciences, Dublin 2, Ireland
| | - Zhuohui Gan
- Human and Animal Physiology, Wageningen University & Research, Wageningen, the Netherlands
| | - Jaap Keijer
- Human and Animal Physiology, Wageningen University & Research, Wageningen, the Netherlands
| | - Merel J W Adjobo-Hermans
- Department of Medical BioSciences, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Werner J H Koopman
- Human and Animal Physiology, Wageningen University & Research, Wageningen, the Netherlands; Department of Pediatrics, Amalia Children's Hospital, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, the Netherlands.
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2
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Dayalan Naidu S, Angelova PR, Knatko EV, Leonardi C, Novak M, de la Vega L, Ganley IG, Abramov AY, Dinkova-Kostova AT. Nrf2 depletion in the context of loss-of-function Keap1 leads to mitolysosome accumulation. Free Radic Biol Med 2023; 208:478-493. [PMID: 37714439 DOI: 10.1016/j.freeradbiomed.2023.09.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/08/2023] [Accepted: 09/10/2023] [Indexed: 09/17/2023]
Abstract
Transcription factor nuclear factor erythroid 2 p45-related factor 2 (Nrf2) is the principal determinant of the cellular redox homeostasis, contributing to mitochondrial function, integrity and bioenergetics. The main negative regulator of Nrf2 is Kelch-like ECH associated protein 1 (Keap1), a substrate adaptor for Cul3/Rbx1 ubiquitin ligase, which continuously targets Nrf2 for ubiquitination and proteasomal degradation. Loss-of-function mutations in Keap1 occur frequently in lung cancer, leading to constitutive Nrf2 activation. We used the human lung cancer cell line A549 and its CRISPR/Cas9-generated homozygous Nrf2-knockout (Nrf2-KO) counterpart to assess the role of Nrf2 on mitochondrial health. To confirm that the observed effects of Nrf2 deficiency are not due to clonal selection or long-term adaptation to the absence of Nrf2, we also depleted Nrf2 by siRNA (siNFE2L2), thus creating populations of Nrf2-knockdown (Nrf2-KD) A549 cells. Nrf2 deficiency decreased mitochondrial respiration, but increased the mitochondrial membrane potential, mass, DNA content, and the number of mitolysosomes. The proportion of ATG7 and ATG3 within their respective LC3B conjugates was increased in Nrf2-deficient cells with mutant Keap1, whereas the formation of new autophagosomes was not affected. Thus, in lung cancer cells with loss-of-function Keap1, Nrf2 facilitates mitolysosome degradation thereby ensuring timely clearance of damaged mitochondria.
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Affiliation(s)
- Sharadha Dayalan Naidu
- Jacqui Wood Cancer Centre, Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, UK
| | | | - Elena V Knatko
- Jacqui Wood Cancer Centre, Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, UK
| | - Chiara Leonardi
- Jacqui Wood Cancer Centre, Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, UK
| | - Miroslav Novak
- Jacqui Wood Cancer Centre, Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, UK
| | - Laureano de la Vega
- Jacqui Wood Cancer Centre, Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, UK
| | - Ian G Ganley
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Andrey Y Abramov
- UCL Queen Square Institute of Neurology, Queen Square, London, UK.
| | - Albena T Dinkova-Kostova
- Jacqui Wood Cancer Centre, Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, UK; Department of Pharmacology and Molecular Sciences and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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3
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Okoye CN, Koren SA, Wojtovich AP. Mitochondrial complex I ROS production and redox signaling in hypoxia. Redox Biol 2023; 67:102926. [PMID: 37871533 PMCID: PMC10598411 DOI: 10.1016/j.redox.2023.102926] [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: 08/31/2023] [Revised: 09/29/2023] [Accepted: 10/06/2023] [Indexed: 10/25/2023] Open
Abstract
Mitochondria are a main source of cellular energy. Oxidative phosphorylation (OXPHOS) is the major process of aerobic respiration. Enzyme complexes of the electron transport chain (ETC) pump protons to generate a protonmotive force (Δp) that drives OXPHOS. Complex I is an electron entry point into the ETC. Complex I oxidizes nicotinamide adenine dinucleotide (NADH) and transfers electrons to ubiquinone in a reaction coupled with proton pumping. Complex I also produces reactive oxygen species (ROS) under various conditions. The enzymatic activities of complex I can be regulated by metabolic conditions and serves as a regulatory node of the ETC. Complex I ROS plays diverse roles in cell metabolism ranging from physiologic to pathologic conditions. Progress in our understanding indicates that ROS release from complex I serves important signaling functions. Increasing evidence suggests that complex I ROS is important in signaling a mismatch in energy production and demand. In this article, we review the role of ROS from complex I in sensing acute hypoxia.
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Affiliation(s)
- Chidozie N Okoye
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Shon A Koren
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Andrew P Wojtovich
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY, 14642, USA; Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, 14642, USA.
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4
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Deline ML, Straub J, Patel M, Subba P, Grashei M, van Heijster FHA, Pirkwieser P, Somoza V, Livingstone JD, Beazely M, Kendall B, Gingras MJP, Leonenko Z, Höschen C, Harrington G, Kuellmer K, Bian W, Schilling F, Fisher MPA, Helgeson ME, Fromme T. Lithium isotopes differentially modify mitochondrial amorphous calcium phosphate cluster size distribution and calcium capacity. Front Physiol 2023; 14:1200119. [PMID: 37781224 PMCID: PMC10540846 DOI: 10.3389/fphys.2023.1200119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 08/21/2023] [Indexed: 10/03/2023] Open
Abstract
Lithium is commonly prescribed as a mood stabilizer in a variety of mental health conditions, yet its molecular mode of action is incompletely understood. Many cellular events associated with lithium appear tied to mitochondrial function. Further, recent evidence suggests that lithium bioactivities are isotope specific. Here we focus on lithium effects related to mitochondrial calcium handling. Lithium protected against calcium-induced permeability transition and decreased the calcium capacity of liver mitochondria at a clinically relevant concentration. In contrast, brain mitochondrial calcium capacity was increased by lithium. Surprisingly, 7Li acted more potently than 6Li on calcium capacity, yet 6Li was more effective at delaying permeability transition. The size distribution of amorphous calcium phosphate colloids formed in vitro was differentially affected by lithium isotopes, providing a mechanistic basis for the observed isotope specific effects on mitochondrial calcium handling. This work highlights a need to better understand how mitochondrial calcium stores are structurally regulated and provides key considerations for future formulations of lithium-based therapeutics.
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Affiliation(s)
- Marshall L. Deline
- Chair of Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Joshua Straub
- Department of Physics, University of California, Santa Barbara, CA, United States
| | - Manisha Patel
- Department of Physics, University of California, Santa Barbara, CA, United States
| | - Pratigya Subba
- Chair of Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Martin Grashei
- Department of Nuclear Medicine, TUM School of Medicine, Technical University of Munich, Munich, Germany
| | - Frits H. A. van Heijster
- Department of Nuclear Medicine, TUM School of Medicine, Technical University of Munich, Munich, Germany
| | - Philip Pirkwieser
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Veronika Somoza
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
- Chair of Nutritional Systems Biology, TUM School of Life Sciences, Technical University of Munich, Munich, Germany
| | | | - Michael Beazely
- School of Pharmacy, University of Waterloo, Waterloo, ON, Canada
| | - Brian Kendall
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Michel J. P. Gingras
- Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada
- CIFAR, MaRS Centre, Toronto, ON, Canada
| | - Zoya Leonenko
- Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Carmen Höschen
- Chair of Soil Science, TUM School of Life Sciences, Technical University of Munich, Munich, Germany
| | - Gertraud Harrington
- Chair of Soil Science, TUM School of Life Sciences, Technical University of Munich, Munich, Germany
| | - Katharina Kuellmer
- Chair of Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Wangqing Bian
- Chair of Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Franz Schilling
- Department of Nuclear Medicine, TUM School of Medicine, Technical University of Munich, Munich, Germany
| | - Matthew P. A. Fisher
- Department of Physics, University of California, Santa Barbara, CA, United States
| | - Matthew E. Helgeson
- Department of Chemical Engineering, University of California, Santa Barbara, CA, United States
| | - Tobias Fromme
- Chair of Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
- EKFZ—Else Kröner-Fresenius Center for Nutritional Medicine, Technical University of Munich, Freising, Germany
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5
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Sadri S, Tomar N, Yang C, Audi SH, Cowley AW, Dash RK. Effects of ROS pathway inhibitors and NADH and FADH 2 linked substrates on mitochondrial bioenergetics and ROS emission in the heart and kidney cortex and outer medulla. Arch Biochem Biophys 2023; 744:109690. [PMID: 37429534 PMCID: PMC10528392 DOI: 10.1016/j.abb.2023.109690] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 07/06/2023] [Indexed: 07/12/2023]
Abstract
Mitochondria are major sources of reactive oxygen species (ROS), which play important roles in both physiological and pathological processes. However, the specific contributions of different ROS production and scavenging components in the mitochondria of metabolically active tissues such as heart and kidney cortex and outer medulla (OM) are not well understood. Therefore, the goal of this study was to determine contributions of different ROS production and scavenging components and provide detailed comparisons of mitochondrial respiration, bioenergetics, ROS emission between the heart and kidney cortex and OM using tissues obtained from the same Sprague-Dawley rat under identical conditions and perturbations. Specifically, data were obtained using both NADH-linked substrate pyruvate + malate and FADH2-linked substrate succinate followed by additions of inhibitors of different components of the electron transport chain (ETC) and oxidative phosphorylation (OxPhos) and other ROS production and scavenging systems. Currently, there is limited data available for the mitochondria of kidney cortex and OM, the two major energy-consuming tissues in the body only next to the heart, and scarce quantitative information on the interplay between mitochondrial ROS production and scavenging systems in the three tissues. The findings from this study demonstrate significant differences in mitochondrial respiratory and bioenergetic functions and ROS emission among the three tissues. The results quantify the rates of ROS production from different complexes of the ETC, identify the complexes responsible for variations in mitochondrial membrane depolarization and regulations of ROS production, and quantify the contributions of ROS scavenging enzymes towards overall mitochondrial ROS emission. These findings advance our fundamental knowledge of tissue-specific and substrate-dependent mitochondrial respiratory and bioenergetic functions and ROS emission. This is important given the critical role that excess ROS production, oxidative stress, and mitochondrial dysfunction in the heart and kidney cortex and OM play in the pathogenesis of cardiovascular and renal diseases, including salt-sensitive hypertension.
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Affiliation(s)
- Shima Sadri
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Namrata Tomar
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Said H Audi
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, 53226, USA; Department of Biomedical Engineering, Marquette University, Milwaukee, WI, 53223, USA
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA; Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Ranjan K Dash
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, 53226, USA; Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA; Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, WI, 53226, USA; Department of Biomedical Engineering, Marquette University, Milwaukee, WI, 53223, USA.
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6
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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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7
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Funk RHW, Scholkmann F. The significance of bioelectricity on all levels of organization of an organism. Part 1: From the subcellular level to cells. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 177:185-201. [PMID: 36481271 DOI: 10.1016/j.pbiomolbio.2022.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/24/2022] [Accepted: 12/03/2022] [Indexed: 12/12/2022]
Abstract
Bioelectricity plays an essential role in the structural and functional organization of biological organisms. In this first article of our three-part series, we summarize the importance of bioelectricity for the basic structural level of biological organization, i.e. from the subcellular level (charges, ion channels, molecules and cell organelles) to cells.
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Affiliation(s)
- Richard H W Funk
- Institute of Anatomy, Center for Theoretical Medicine, TU-Dresden, 01307, Dresden, Germany; Dresden International University, 01067, Dresden, Germany.
| | - Felix Scholkmann
- Biomedical Optics Research Laboratory, Department of Neonatology, University Hospital Zurich, University of Zurich, 8091, Zurich, Switzerland.
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The Short-Term Opening of Cyclosporin A-Independent Palmitate/Sr2+-Induced Pore Can Underlie Ion Efflux in the Oscillatory Mode of Functioning of Rat Liver Mitochondria. MEMBRANES 2022; 12:membranes12070667. [PMID: 35877870 PMCID: PMC9319229 DOI: 10.3390/membranes12070667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 06/24/2022] [Accepted: 06/27/2022] [Indexed: 11/17/2022]
Abstract
Mitochondria are capable of synchronized oscillations in many variables, but the underlying mechanisms are still unclear. In this study, we demonstrated that rat liver mitochondria, when exposed to a pulse of Sr2+ ions in the presence of valinomycin (a potassium ionophore) and cyclosporin A (a specific inhibitor of the permeability transition pore complex) under hypotonia, showed prolonged oscillations in K+ and Sr2+ fluxes, membrane potential, pH, matrix volume, rates of oxygen consumption and H2O2 formation. The dynamic changes in the rate of H2O2 production were in a reciprocal relationship with the respiration rate and in a direct relationship with the mitochondrial membrane potential and other indicators studied. The pre-incubation of mitochondria with Ca2+(Sr2+)-dependent phospholipase A2 inhibitors considerably suppressed the accumulation of free fatty acids, including palmitic and stearic acids, and all spontaneous Sr2+-induced cyclic changes. These data suggest that the mechanism of ion efflux from mitochondria is related to the opening of short-living pores, which can be caused by the formation of complexes between Sr2+(Ca2+) and endogenous long-chain saturated fatty acids (mainly, palmitic acid) that accumulate due to the activation of phospholipase A2 by the ions. A possible role for transient palmitate/Ca2+(Sr2+)-induced pores in the maintenance of ion homeostasis and the prevention of calcium overload in mitochondria under pathophysiological conditions is discussed.
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9
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Mitochondrial Ca 2+ Homeostasis: Emerging Roles and Clinical Significance in Cardiac Remodeling. Int J Mol Sci 2022; 23:ijms23063025. [PMID: 35328444 PMCID: PMC8954803 DOI: 10.3390/ijms23063025] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/01/2022] [Accepted: 03/03/2022] [Indexed: 01/27/2023] Open
Abstract
Mitochondria are the sites of oxidative metabolism in eukaryotes where the metabolites of sugars, fats, and amino acids are oxidized to harvest energy. Notably, mitochondria store Ca2+ and work in synergy with organelles such as the endoplasmic reticulum and extracellular matrix to control the dynamic balance of Ca2+ concentration in cells. Mitochondria are the vital organelles in heart tissue. Mitochondrial Ca2+ homeostasis is particularly important for maintaining the physiological and pathological mechanisms of the heart. Mitochondrial Ca2+ homeostasis plays a key role in the regulation of cardiac energy metabolism, mechanisms of death, oxygen free radical production, and autophagy. The imbalance of mitochondrial Ca2+ balance is closely associated with cardiac remodeling. The mitochondrial Ca2+ uniporter (mtCU) protein complex is responsible for the uptake and release of mitochondrial Ca2+ and regulation of Ca2+ homeostasis in mitochondria and consequently, in cells. This review summarizes the mechanisms of mitochondrial Ca2+ homeostasis in physiological and pathological cardiac remodeling and the regulatory effects of the mitochondrial calcium regulatory complex on cardiac energy metabolism, cell death, and autophagy, and also provides the theoretical basis for mitochondrial Ca2+ as a novel target for the treatment of cardiovascular diseases.
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10
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Mohammadnejad L, Soltaninejad K, Seyedabadi M, Ghasem Pouri SK, Shokrzadeh M, Mohammadi H. Evaluation of mitochondrial dysfunction due to oxidative stress in therapeutic, toxic and lethal concentrations of tramadol. Toxicol Res (Camb) 2021; 10:1162-1170. [PMID: 34956619 DOI: 10.1093/toxres/tfab096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 09/01/2021] [Accepted: 10/05/2021] [Indexed: 12/12/2022] Open
Abstract
Tramadol (TR) is a centrally acting analgesic drug that is used to relieve pain. The therapeutic (0.1-0.8 mg/l), toxic (1-2 mg/l) and lethal (>2 mg/l) ranges were reported for TR. The present study was designed to evaluate which doses of TR can induce liver mitochondrial toxicity. Mitochondria were isolated from the five rats' liver and were incubated with therapeutic to lethal concentrations (1.7-600 μM) of TR. Biomarkers of oxidative stress including: reactive oxygen species (ROS), lipid peroxidation (LPO), protein carbonyl content, glutathione (GSH) content, mitochondrial function, mitochondrial membrane potential (MMP) and mitochondrial swelling were assessed. Our results showed that ROS and LPO at 100 μM and protein carbonylation at 600 μM concentrations of TR were significantly increased. GSH was decreased specifically at 600 μM concentration. Mitochondrial function, MMP and mitochondrial swelling decreased in isolated rat liver mitochondria after exposure to 100 and 300 μM, respectively. This study suggested that TR at therapeutic and toxic levels by single exposure could not induce mitochondrial toxicity. But, in lethal concentration (≥100 μM), TR induced oxidative damage and mitochondria dysfunction. This study suggested that ROS overproduction by increasing of TR concentration induced mitochondrial dysfunction and caused mitochondrial damage via Complex II and membrane permeability transition pores disorders, MMP collapse and mitochondria swelling.
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Affiliation(s)
- Leila Mohammadnejad
- Department of Toxicology and Pharmacology, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari 48157-33971, Iran
| | - Kambiz Soltaninejad
- Department of Forensic Toxicology, Legal Medicine Research Center, Legal Medicine Organization, Tehran 48157-33971, Iran
| | - Mohammad Seyedabadi
- Department of Toxicology and Pharmacology, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari 48157-33971, Iran
| | - Seyed Khosro Ghasem Pouri
- Department of Emergency Medicine, School of Medicine, Antimicrobial Resistance Research Center, Ghaem Shahr Razi Hospital, Mazandaran University of Medical Sciences, Sari 48157-33971, Iran
| | - Mohammad Shokrzadeh
- Department of Toxicology and Pharmacology, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari 48157-33971, Iran
| | - Hamidreza Mohammadi
- Department of Toxicology and Pharmacology, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari 48157-33971, Iran
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NAD(H) Regulates the Permeability Transition Pore in Mitochondria through an External Site. Int J Mol Sci 2021; 22:ijms22168560. [PMID: 34445270 PMCID: PMC8395297 DOI: 10.3390/ijms22168560] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/28/2021] [Accepted: 08/05/2021] [Indexed: 11/17/2022] Open
Abstract
The opening of the permeability transition pore (mPTP) in mitochondria initiates cell death in numerous diseases. The regulation of mPTP by NAD(H) in the mitochondrial matrix is well established; however, the role of extramitochondrial (cytosolic) NAD(H) is still unclear. We studied the effect of added NADH and NAD+ on: (1) the Ca2+-retention capacity (CRC) of isolated rat liver, heart, and brain mitochondria; (2) the Ca2+-dependent mitochondrial swelling in media whose particles can (KCl) or cannot (sucrose) be extruded from the matrix by mitochondrial carriers; (3) the Ca2+-dependent mitochondrial depolarization and the release of entrapped calcein from mitochondria of permeabilized hepatocytes; and (4) the Ca2+-dependent mitochondrial depolarization and subsequent repolarization. NADH and NAD+ increased the CRC of liver, heart, and brain mitochondria 1.5-2.5 times, insignificantly affecting the rate of Ca2+-uptake and the free Ca2+ concentration in the medium. NAD(H) suppressed the Ca2+-dependent mitochondrial swelling both in KCl- and sucrose-based media but did not induce the contraction and repolarization of swollen mitochondria. By contrast, EGTA caused mitochondrial repolarization in both media and the contraction in KCl-based medium only. NAD(H) delayed the Ca2+-dependent depolarization and the release of calcein from individual mitochondria in hepatocytes. These data unambiguously demonstrate the existence of an external NAD(H)-dependent site of mPTP regulation.
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12
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Aklima J, Onojima T, Kimura S, Umiuchi K, Shibata T, Kuraoka Y, Oie Y, Suganuma Y, Ohta Y. Effects of Matrix pH on Spontaneous Transient Depolarization and Reactive Oxygen Species Production in Mitochondria. Front Cell Dev Biol 2021; 9:692776. [PMID: 34277637 PMCID: PMC8278022 DOI: 10.3389/fcell.2021.692776] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 05/26/2021] [Indexed: 01/28/2023] Open
Abstract
Reactive oxygen species (ROS) oxidize surrounding molecules and thus impair their functions. Since mitochondria are a major source of ROS, suppression of ROS overproduction in the mitochondria is important for cells. Spontaneous transient depolarization of individual mitochondria is a physiological phenomenon widely observed from plants to mammals. Mitochondrial uncoupling can reduce ROS production; therefore, it is conceivable that transient depolarization could reduce ROS production. However, transient depolarization has been observed with increased ROS production. Therefore, the exact contribution of transient depolarization to ROS production has not been elucidated. In this study, we examined how the spontaneous transient depolarization occurring in individual mitochondria affected ROS production. When the matrix pH increased after the addition of malate or exposure of the isolated mitochondria to a high-pH buffer, transient depolarization was stimulated. Similar stimulation by an increased matrix pH was also observed in the mitochondria in intact H9c2 cells. Modifying the mitochondrial membrane potential and matrix pH by adding K+ in the presence of valinomycin, a K+ ionophore, clarified that an increase in the matrix pH is a major cause of ROS generation. When we added ADP in the presence of oligomycin to suppress the transient depolarization without decreasing the matrix pH, we observed the suppression of mitochondrial respiration, increased matrix pH, and enhanced ROS production. Based on these results, we propose a model where spontaneous transient depolarization occurs during increased proton influx through proton channels opened by increased matrix pH, leading to the suppression of ROS production. This study improves our understanding of mitochondrial behavior.
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Affiliation(s)
- Jannatul Aklima
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Japan.,Department of Biochemistry and Molecular Biology, University of Chittagong, Chittagong, Bangladesh
| | - Takumi Onojima
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Japan
| | - Sawako Kimura
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Japan
| | - Kanji Umiuchi
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Japan
| | - Takahiro Shibata
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Japan
| | - Yusho Kuraoka
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Japan
| | - Yoshiki Oie
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Japan
| | - Yoshiki Suganuma
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Japan
| | - Yoshihiro Ohta
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Japan
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13
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Wang B, Li Y, You C. miR-129-3p Targeting of MCU Protects Against Glucose Fluctuation-Mediated Neuronal Damage via a Mitochondrial-Dependent Intrinsic Apoptotic Pathway. Diabetes Metab Syndr Obes 2021; 14:153-163. [PMID: 33488104 PMCID: PMC7815084 DOI: 10.2147/dmso.s285179] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 12/12/2020] [Indexed: 02/05/2023] Open
Abstract
INTRODUCTION Glucose fluctuations have an adverse effect on several diabetes-related complications, especially for the nervous system, but the underlying mechanisms are not clear. MicroRNAs are critical regulators of posttranscription in many physiological processes, such as apoptosis. Our study clarified the neuroprotective effects of miR-129-3p targeting mitochondrial calcium uniporter (MCU) in glucose fluctuation-mediated neuronal damage and the specific mechanisms involved. METHODS The expression of MCU and miR-129-3p was examined by real-time PCR and Western blot in the glucose fluctuation cell model. Dual-luciferase reporter assay was performed to confirm the transcriptional regulation of miR-129-3p by MCU. Fluorescent probe and assay kit assay was used to determine oxidative stress condition. Mitochondrial-dependent intrinsic apoptotic factors were examined by flow cytometry assay, enzyme-linked immunosorbent assay (ELISA), and gene and protein expression assays. RESULTS We found an upregulation of MCU and downregulation of miR-129-3p in glucose fluctuation-treated primary hippocampal neuronal cells, and miR-129-3p directly targeted MCU. miR-129-3p overexpression produced a dramatic reduction in calcium overload, reactive oxygen species (ROS) generation, GSH-to-GSSG ratio, MMP-2 expression in the mitochondrial-dependent intrinsic apoptosis pathway and an increase in MnSOD activity. Increasing MCU expression rescued the effects of miR-129-3p overexpression. miR-129-3p downregulation produced a significant increase in calcium overload, reactive oxygen species (ROS) generation, MMP-2 expression, cytochrome c release and cell apoptosis, and antioxidant N-acetyl cysteine (NAC) rescued the effects of miR-129-3p downregulation. CONCLUSION Therefore, miR-129-3p suppressed glucose fluctuation-mediated neuronal damage by targeting MCU via a mitochondrial-dependent intrinsic apoptotic pathway. The miR-129-3p/MCU axis may be a promising therapeutic target for glucose fluctuation-mediated neuronal damage.
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Affiliation(s)
- Bo Wang
- Department of Neurosurgery, West China School of Medicine/West China Hospital of Sichuan University, Chengdu, Sichuan610041, People’s Republic of China
- Department of Neurosurgery, Kunming Medical University First Affiliated Hospital, Kunming, Yunnan650032, People’s Republic of China
| | - Yang Li
- Intensive Care Unit, West China School of Medicine/West China Hospital of Sichuan University, Chengdu, Sichuan610041, People’s Republic of China
| | - Chao You
- Department of Neurosurgery, West China School of Medicine/West China Hospital of Sichuan University, Chengdu, Sichuan610041, People’s Republic of China
- Correspondence: Chao You Department of Neurosurgery, West China School of Medicine/West China Hospital of Sichuan University, Chengdu, Sichuan610041, People’s Republic of ChinaTel +86 28-85422026 Email
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14
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Gottwald EM, Schuh CD, Drücker P, Haenni D, Pearson A, Ghazi S, Bugarski M, Polesel M, Duss M, Landau EM, Kaech A, Ziegler U, Lundby AKM, Lundby C, Dittrich PS, Hall AM. The iron chelator Deferasirox causes severe mitochondrial swelling without depolarization due to a specific effect on inner membrane permeability. Sci Rep 2020; 10:1577. [PMID: 32005861 PMCID: PMC6994599 DOI: 10.1038/s41598-020-58386-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 01/15/2020] [Indexed: 12/13/2022] Open
Abstract
The iron chelator Deferasirox (DFX) causes severe toxicity in patients for reasons that were previously unexplained. Here, using the kidney as a clinically relevant in vivo model for toxicity together with a broad range of experimental techniques, including live cell imaging and in vitro biophysical models, we show that DFX causes partial uncoupling and dramatic swelling of mitochondria, but without depolarization or opening of the mitochondrial permeability transition pore. This effect is explained by an increase in inner mitochondrial membrane (IMM) permeability to protons, but not small molecules. The movement of water into mitochondria is prevented by altering intracellular osmotic gradients. Other clinically used iron chelators do not produce mitochondrial swelling. Thus, DFX causes organ toxicity due to an off-target effect on the IMM, which has major adverse consequences for mitochondrial volume regulation.
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Affiliation(s)
| | - Claus D Schuh
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Patrick Drücker
- Department of Biosystems Science and Engineering, ETH Zurich, Zurich, Switzerland
| | - Dominik Haenni
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Adam Pearson
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Susan Ghazi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Milica Bugarski
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | | | - Michael Duss
- Department of Chemistry, University of Zurich, Zurich, Switzerland
| | - Ehud M Landau
- Department of Chemistry, University of Zurich, Zurich, Switzerland
| | - Andres Kaech
- Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Urs Ziegler
- Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Anne K M Lundby
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Carsten Lundby
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Petra S Dittrich
- Department of Biosystems Science and Engineering, ETH Zurich, Zurich, Switzerland
| | - Andrew M Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland. .,Department of Nephrology, University Hospital Zurich, Zurich, Switzerland.
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15
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Tsakiri EN, Gumeni S, Vougas K, Pendin D, Papassideri I, Daga A, Gorgoulis V, Juhász G, Scorrano L, Trougakos IP. Proteasome dysfunction induces excessive proteome instability and loss of mitostasis that can be mitigated by enhancing mitochondrial fusion or autophagy. Autophagy 2019; 15:1757-1773. [PMID: 31002009 PMCID: PMC6735541 DOI: 10.1080/15548627.2019.1596477] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The ubiquitin-proteasome pathway (UPP) is central to proteostasis network (PN) functionality and proteome quality control. Yet, the functional implication of the UPP in tissue homeodynamics at the whole organism level and its potential cross-talk with other proteostatic or mitostatic modules are not well understood. We show here that knock down (KD) of proteasome subunits in Drosophila flies, induced, for most subunits, developmental lethality. Ubiquitous or tissue specific proteasome dysfunction triggered systemic proteome instability and activation of PN modules, including macroautophagy/autophagy, molecular chaperones and the antioxidant cncC (the fly ortholog of NFE2L2/Nrf2) pathway. Also, proteasome KD increased genomic instability, altered metabolic pathways and severely disrupted mitochondrial functionality, triggering a cncC-dependent upregulation of mitostatic genes and enhanced rates of mitophagy. Whereas, overexpression of key regulators of antioxidant responses (e.g., cncC or foxo) could not suppress the deleterious effects of proteasome dysfunction; these were alleviated in both larvae and adult flies by modulating mitochondrial dynamics towards increased fusion or by enhancing autophagy. Our findings reveal the extensive functional wiring of genomic, proteostatic and mitostatic modules in higher metazoans. Also, they support the notion that age-related increase of proteotoxic stress due to decreased UPP activity deregulates all aspects of cellular functionality being thus a driving force for most age-related diseases. Abbreviations: ALP: autophagy-lysosome pathway; ARE: antioxidant response element; Atg8a: autophagy-related 8a; ATPsynβ: ATP synthase, β subunit; C-L: caspase-like proteasomal activity; cncC: cap-n-collar isoform-C; CT-L: chymotrypsin-like proteasomal activity; Drp1: dynamin related protein 1; ER: endoplasmic reticulum; foxo: forkhead box, sub-group O; GLU: glucose; GFP: green fluorescent protein; GLY: glycogen; Hsf: heat shock factor; Hsp: Heat shock protein; Keap1: kelch-like ECH-associated protein 1; Marf: mitochondrial assembly regulatory factor; NFE2L2/Nrf2: nuclear factor, erythroid 2 like 2; Opa1: optic atrophy 1; PN: proteostasis network; RNAi: RNA interference; ROS: reactive oxygen species; ref(2)P: refractory to sigma P; SQSTM1: sequestosome 1; SdhA: succinate dehydrogenase, subunit A; T-L: trypsin-like proteasomal activity; TREH: trehalose; UAS: upstream activation sequence; Ub: ubiquitin; UPR: unfolded protein response; UPP: ubiquitin-proteasome pathway.
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Affiliation(s)
- Eleni N Tsakiri
- Department of Cell Biology and Biophysics, Faculty of Biology, National and Kapodistrian University of Athens , Athens , Greece
| | - Sentiljana Gumeni
- Department of Cell Biology and Biophysics, Faculty of Biology, National and Kapodistrian University of Athens , Athens , Greece
| | - Konstantinos Vougas
- Genomics and Proteomics Research Units, Center of Basic Research II, Biomedical Research Foundation, Academy of Athens , Athens , Greece
| | - Diana Pendin
- Department of Biomedical Sciences, University of Padova , Padova , Italy
| | - Issidora Papassideri
- Department of Cell Biology and Biophysics, Faculty of Biology, National and Kapodistrian University of Athens , Athens , Greece
| | - Andrea Daga
- Laboratory of Molecular Biology, Scientific Institute, IRCCS E. Medea , Lecco , Italy
| | - Vassilis Gorgoulis
- Genomics and Proteomics Research Units, Center of Basic Research II, Biomedical Research Foundation, Academy of Athens , Athens , Greece.,Department of Histology and Embryology, School of Medicine, National and Kapodistrian University of Athens , Athens , Greece.,Faculty of Biology, Medicine and Health, University of Manchester , Manchester , UK
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, Hungary and Biological Research Centre, Hungarian Academy of Sciences , Szeged , Hungary
| | - Luca Scorrano
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine and Department of Biology, University of Padua , Padova , Italy
| | - Ioannis P Trougakos
- Department of Cell Biology and Biophysics, Faculty of Biology, National and Kapodistrian University of Athens , Athens , Greece
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16
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Zhang L, Wang H, Zhou X, Mao L, Ding K, Hu Z. Role of mitochondrial calcium uniporter-mediated Ca 2+ and iron accumulation in traumatic brain injury. J Cell Mol Med 2019; 23:2995-3009. [PMID: 30756474 PMCID: PMC6433723 DOI: 10.1111/jcmm.14206] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 12/28/2018] [Accepted: 01/16/2019] [Indexed: 12/17/2022] Open
Abstract
Previous studies have suggested that the cellular Ca2+ and iron homeostasis, which can be regulated by mitochondrial calcium uniporter (MCU), is associated with oxidative stress, apoptosis and many neurological diseases. However, little is known about the role of MCU‐mediated Ca2+ and iron accumulation in traumatic brain injury (TBI). Under physiological conditions, MCU can be inhibited by ruthenium red (RR) and activated by spermine (Sper). In the present study, we used RR and Sper to reveal the role of MCU in mouse and neuron TBI models. Our results suggested that the Ca2+ and iron concentrations were obviously increased after TBI. In addition, TBI models showed a significant generation of reactive oxygen species (ROS), decrease in adenosine triphosphate (ATP), deformation of mitochondria, up‐regulation of deoxyribonucleic acid (DNA) damage and increase in apoptosis. Blockage of MCU by RR prevented Ca2+ and iron accumulation, abated the level of oxidative stress, improved the energy supply, stabilized mitochondria, reduced DNA damage and decreased apoptosis both in vivo and in vitro. Interestingly, Sper did not increase cellular Ca2+ and iron concentrations, but suppressed the Ca2+ and iron accumulation to benefit the mice in vivo. However, Sper had no significant impact on TBI in vitro. Taken together, our data demonstrated for the first time that blockage of MCU‐mediated Ca2+ and iron accumulation was essential for TBI. These findings indicated that MCU could be a novel therapeutic target for treating TBI.
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Affiliation(s)
- Li Zhang
- Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu Province, China
| | - Handong Wang
- Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu Province, China
| | - Xiaoming Zhou
- Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu Province, China
| | - Lei Mao
- Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu Province, China
| | - Ke Ding
- Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu Province, China
| | - Zhigang Hu
- Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu Province, China
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17
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Pardo-Peña K, Lorea-Hernández JJ, Camacho-Hernández NP, Ordaz B, Villasana-Salazar B, Morales-Villagrán A, Peña-Ortega F. Hydrogen peroxide extracellular concentration in the ventrolateral medulla and its increase in response to hypoxia in vitro: Possible role of microglia. Brain Res 2018; 1692:87-99. [DOI: 10.1016/j.brainres.2018.04.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 03/31/2018] [Accepted: 04/25/2018] [Indexed: 12/12/2022]
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18
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Kamei Y, Koushi M, Aoyama Y, Asakai R. The yeast mitochondrial permeability transition is regulated by reactive oxygen species, endogenous Ca 2+ and Cpr3, mediating cell death. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:1313-1326. [PMID: 30031690 DOI: 10.1016/j.bbabio.2018.07.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 07/13/2018] [Accepted: 07/16/2018] [Indexed: 11/29/2022]
Abstract
We investigated the properties of the permeability transition pore (PTP) in Saccharomyces cerevisiae in agar-embedded mitochondria (AEM) and agar-embedded cells (AEC) and its role in yeast death. In AEM, ethanol-induced pore opening, as indicated by the release of calcein and mitochondrial membrane depolarization, can be inhibited by CsA, by Cpr3 deficiency, and by the antioxidant glutathione. Notably, the pore opening is inhibited, when mitochondria are preloaded by EGTA or Fluo3 to chelate matrix Ca2+, or are pretreated with 4-Br A23187 to extract matrix Ca2+, prior to agar-embedding, or when pore opening is induced in the presence of EGTA; opened pores are re-closed by sequential treatment with CsA, 4-Br A23187 plus EGTA and NADH, indicating endogenous matrix Ca2+ involvement. CsA also inhibits the pore opening with low conductance triggered by exogenous Ca2+ transport with ETH129. In AEC, the treatment of tert-butylhydroperoxide, a pro-oxidant that triggers transient pore opening in high conductance in AEM, induces yeast death, which is also dependent on CsA and Cpr3. Furthermore, AEMs from mutants lacking three ADP/ATP carrier (AAC) isoforms and with defective ATP synthase dimerization exhibit high and low conductance pore openings with CsA sensitivity, respectively. Collectively, these data show that the yeast PTP is regulated by Cpr3, endogenous matrix Ca2+, and reactive oxygen species, and that it is involved in yeast death; furthermore, ATP synthase dimers play a key role in CsA-sensitive pore formation, while AACs are dispensable.
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Affiliation(s)
- Yoshiko Kamei
- Department of Morphophysiology, Faculty of Pharmaceutical Sciences, Josai International University, 1 Gumyo, Togane, Chiba 283-8555, Japan
| | - Masami Koushi
- Department of Morphophysiology, Faculty of Pharmaceutical Sciences, Josai International University, 1 Gumyo, Togane, Chiba 283-8555, Japan
| | - Yasunori Aoyama
- Department of Morphophysiology, Faculty of Pharmaceutical Sciences, Josai International University, 1 Gumyo, Togane, Chiba 283-8555, Japan
| | - Rei Asakai
- Department of Morphophysiology, Faculty of Pharmaceutical Sciences, Josai International University, 1 Gumyo, Togane, Chiba 283-8555, Japan.
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19
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Magnesium Extravaganza: A Critical Compendium of Current Research into Cellular Mg 2+ Transporters Other than TRPM6/7. Rev Physiol Biochem Pharmacol 2018; 176:65-105. [PMID: 30406297 DOI: 10.1007/112_2018_15] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Magnesium research has boomed within the last 20 years. The real breakthrough came at the start of the new millennium with the discovery of a plethora of possible Mg homeostatic factors that, in particular, included putative Mg2+ transporters. Until that point, Mg research was limited to biochemical and physiological work, as no target molecular entities were known that could be used to explore the molecular biology of Mg homeostasis at the level of the cell, tissue, organ, or organism and to translate such knowledge into the field of clinical medicine and pharmacology. Because of the aforementioned, Mg2+ and Mg homeostasis, both of which had been heavily marginalized within the biomedical field in the twentieth century, have become overnight a focal point of many studies ranging from primary biomedical research to translational medicine.The amount of literature concerning cellular Mg2+ transport and cellular Mg homeostasis is increasing, together with a certain amount of confusion, especially about the function(s) of the newly discovered and, in the majority of instances, still only putative Mg2+ transporters/Mg2+ homeostatic factors. Newcomers to the field of Mg research will thus find it particularly difficult to orient themselves.Here, we briefly but critically summarize the status quo of the current understanding of the molecular entities behind cellular Mg2+ homeostasis in mammalian/human cells other than TRPM6/7 chanzymes, which have been universally accepted as being unspecific cation channel kinases allowing the flux of Mg2+ while constituting the major gateway for Mg2+ to enter the cell.
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20
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Ayoub IM, Radhakrishnan J, Gazmuri RJ. In vivo opening of the mitochondrial permeability transition pore in a rat model of ventricular fibrillation and closed-chest resuscitation. Am J Transl Res 2017; 9:3345-3359. [PMID: 28804552 PMCID: PMC5553884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Accepted: 08/11/2016] [Indexed: 06/07/2023]
Abstract
Opening of the mitochondrial permeability transition pore (mPTP) is considered central to reperfusion injury. Yet, most of our knowledge comes from observations in isolated mitochondria, cells, and organs. We used a rat model of ventricular fibrillation (VF) and closed-chest resuscitation to examine whether the mPTP opens in vivo and whether cyclosporine A (CsA) attenuates the associated myocardial injury. Two series of 26 and 18 rats each underwent 10 minutes of untreated VF before attempting resuscitation. In series-1, rats received 50 µCi of tritium-labeled 2-deoxyglucose ([3H]DOG) harvesting their hearts at baseline (n=5), during VF (n=5), during resuscitation (n=6), and at post-resuscitation 60 minutes (n=5) and 240 minutes (n=5). mPTP opening was estimated measuring the ratio of mitochondria to left ventricular intracellular [3H]. In series-2, rats received 10 mg/kg of CsA or vehicle before resuscitation, measuring mitochondrial NAD+ content to indirectly assess mPTP opening. In Series-1, the mPTP opening ratio vs baseline (10.4 ± 1.9) increased during VF (16.8 ± 2.4, NS), closed-chest resuscitation (20.8 ± 6.3, P<0.05), and at post-resuscitation 60 minutes (20.9 ± 4.7, P<0.05) and 240 minutes (25.7 ± 11.0, P<0.01). In series 2, CsA failed to attenuate reductions in mitochondrial NAD+ and did not affect plasma cytochrome c, plasma cardiac troponin I, myocardial function, and survival. We report for the first time in an intact rat model of VF that mPTP opens during closed-chest resuscitation consistent with previous observations in mitochondria, cells, and organs of mPTP opening upon reperfusion. CsA, at the dose of 10 mg/kg neither prevented mPTP opening nor attenuated post-resuscitation myocardial injury.
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Affiliation(s)
- Iyad M Ayoub
- Resuscitation Institute at Rosalind Franklin University of Medicine and ScienceNorth Chicago, Illinois, USA
| | - Jeejabai Radhakrishnan
- Resuscitation Institute at Rosalind Franklin University of Medicine and ScienceNorth Chicago, Illinois, USA
| | - Raúl J Gazmuri
- Resuscitation Institute at Rosalind Franklin University of Medicine and ScienceNorth Chicago, Illinois, USA
- Critical Care Medicine, Captain James A Lovell Federal Health Care CenterNorth Chicago, Illinois, USA
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21
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Zand K, Pham TDA, Li J, Zhou W, Wallace DC, Burke PJ. Resistive flow sensing of vital mitochondria with nanoelectrodes. Mitochondrion 2017; 37:8-16. [PMID: 28655663 DOI: 10.1016/j.mito.2017.06.003] [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: 07/12/2016] [Revised: 02/23/2017] [Accepted: 06/21/2017] [Indexed: 12/15/2022]
Abstract
We report label-free detection of single mitochondria with high sensitivity using nanoelectrodes. Measurements of the conductance of carbon nanotube transistors show discrete changes of conductance as individual mitochondria flow over the nanoelectrodes in a microfluidic channel. Altering the bioenergetic state of the mitochondria by adding metabolites to the flow buffer induces changes in the mitochondrial membrane potential detected by the nanoelectrodes. During the time when mitochondria are transiently passing over the nanoelectrodes, this (nano) technology is sensitive to fluctuations of the mitochondrial membrane potential with a resolution of 10mV with temporal resolution of order milliseconds. Fluorescence based assays (in ideal, photon shot noise limited setups) are shown to be an order of magnitude less sensitive than this nano-electronic measurement technology. This opens a new window into the dynamics of an organelle critical to cellular function and fate.
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Affiliation(s)
- Katayoun Zand
- Integrated Nanosystems Research Facility, Electrical Engineering and Computer Science, University of California, Irvine, Irvine, CA 92697, United States
| | - Ted D A Pham
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697, United States
| | - Jinfeng Li
- Integrated Nanosystems Research Facility, Electrical Engineering and Computer Science, University of California, Irvine, Irvine, CA 92697, United States
| | - Weiwei Zhou
- Integrated Nanosystems Research Facility, Electrical Engineering and Computer Science, University of California, Irvine, Irvine, CA 92697, United States
| | - Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia and Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Peter J Burke
- Integrated Nanosystems Research Facility, Electrical Engineering and Computer Science, University of California, Irvine, Irvine, CA 92697, United States.
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22
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Pham TD, Pham PQ, Li J, Letai AG, Wallace DC, Burke PJ. Cristae remodeling causes acidification detected by integrated graphene sensor during mitochondrial outer membrane permeabilization. Sci Rep 2016; 6:35907. [PMID: 27786282 PMCID: PMC5081517 DOI: 10.1038/srep35907] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 10/07/2016] [Indexed: 12/31/2022] Open
Abstract
The intrinsic apoptotic pathway and the resultant mitochondrial outer membrane permeabilization (MOMP) via BAK and BAX oligomerization, cytochrome c (cytc) release, and caspase activation are well studied, but their effect on cytosolic pH is poorly understood. Using isolated mitochondria, we show that MOMP results in acidification of the surrounding medium. BAK conformational changes associated with MOMP activate the OMA1 protease to cleave OPA1 resulting in remodeling of the cristae and release of the highly concentrated protons within the cristae invaginations. This was revealed by utilizing a nanomaterial graphene as an optically clear and ultrasensitive pH sensor that can measure ionic changes induced by tethered mitochondria. With this platform, we have found that activation of mitochondrial apoptosis is accompanied by a gradual drop in extra-mitochondrial pH and a decline in membrane potential, both of which can be rescued by adding exogenous cytc. These findings have importance for potential pharmacological manipulation of apoptosis, in the treatment of cancer.
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Affiliation(s)
- Ted D. Pham
- Department of Biomedical Engineering, University of California, Irvine, CA, USA
| | - Phi Q. Pham
- Department of Chemical Engineering and Materials Science, University of California, Irvine, CA, USA
| | - Jinfeng Li
- Department of Chemical Engineering and Materials Science, University of California, Irvine, CA, USA
| | - Anthony G. Letai
- Dana-Farber Cancer Institute, Harvard University, Boston, MA, USA
| | - Douglas C. Wallace
- Center for Mitochondrial and Epigenomic Medicine, Children’s Hospital of Philadelphia and Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Peter J. Burke
- Department of Biomedical Engineering, University of California, Irvine, CA, USA
- Department of Chemical Engineering and Materials Science, University of California, Irvine, CA, USA
- Department of Electrical Engineering and Computer Science, University of California, Irvine, CA, USA
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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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24
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Kif5 regulates mitochondrial movement, morphology, function and neuronal survival. Mol Cell Neurosci 2016; 72:22-33. [PMID: 26767417 DOI: 10.1016/j.mcn.2015.12.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 12/15/2015] [Accepted: 12/31/2015] [Indexed: 11/21/2022] Open
Abstract
Due to the unique architecture of neurons, trafficking of mitochondria throughout processes to regions of high energetic demand is critical to sustain neuronal health. It has been suggested that compromised mitochondrial trafficking may play a role in neurodegenerative diseases. We evaluated the consequences of disrupted kif5c-mediated mitochondrial trafficking on mitochondrial form and function in primary rat cortical neurons. Morphological changes in mitochondria appeared to be due to remodelling, a phenomenon distinct from mitochondrial fission, which resulted in punctate-shaped mitochondria. We also demonstrated that neurons displaying punctate mitochondria exhibited relatively decreased ROS and increased cellular ATP levels using ROS-sensitive GFP and ATP FRET probes, respectively. Somewhat unexpectedly, neurons overexpressing the dominant negative form of kif5c exhibited enhanced survival following excitotoxicity, suggesting that the impairment of mitochondrial trafficking conferred some form of neuroprotection. However, when neurons were exposed to H2O2, disruption of kif5c exacerbated cell death indicating that the effect on cell viability was dependent on the mode of toxicity. Our results suggest a novel role of kif5c. In addition to mediating mitochondrial transport, kif5c plays a role in the mechanism of regulating mitochondrial morphology. Our results also suggest that kif5c mediated mitochondrial dynamics may play an important role in regulating mitochondrial function and in turn cellular health. Moreover, our studies demonstrate an interesting interplay between the regulation of mitochondrial motility and morphology.
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25
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Li Y, Honda S, Iwami K, Ohta Y, Umeda N. Analysis of mitochondrial mechanical dynamics using a confocal fluorescence microscope with a bent optical fibre. J Microsc 2015; 260:140-51. [PMID: 26249642 DOI: 10.1111/jmi.12277] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Accepted: 05/26/2015] [Indexed: 01/09/2023]
Abstract
The cells in the cardiovascular system are constantly subjected to mechanical forces created by blood flow and the beating heart. The effect of forces on cells has been extensively investigated, but their effect on cellular organelles such as mitochondria remains unclear. We examined the impact of nano-Newton forces on mitochondria using a bent optical fibre (BOF) with a flat-ended tip (diameter exceeding 2 μm) and a confocal fluorescence microscope. By indenting a single mitochondrion with the BOF tip, we found that the mitochondrial elastic modulus was proportional to the (-1/2) power of the mitochondrial radius in the 9.6-115 kPa range. We stained the mitochondria with a potential-metric dye (TMRE) and measured the changes in TMRE fluorescence intensity. We confirmed that more active mitochondria exhibit a higher frequency of repetitive transient depolarization. The same trend was observed at forces lower than 50 nN. We further showed that the depolarization frequency of mitochondria decreases under an extremely large force (nearly 100 nN). We conclude that mitochondrial function is affected by physical environmental factors, such as external forces at the nano-Newton level.
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Affiliation(s)
- Yongbo Li
- Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Satoshi Honda
- Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Kentaro Iwami
- Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Yoshihiro Ohta
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Norihiro Umeda
- Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
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Role of the Mitochondrial Calcium Uniporter in Rat Hippocampal Neuronal Death After Pilocarpine-Induced Status Epilepticus. Neurochem Res 2015; 40:1739-46. [DOI: 10.1007/s11064-015-1657-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/23/2015] [Accepted: 07/01/2015] [Indexed: 12/31/2022]
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27
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In vivo tissue-wide synchronization of mitochondrial metabolic oscillations. Cell Rep 2014; 9:514-21. [PMID: 25373899 DOI: 10.1016/j.celrep.2014.09.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 06/09/2014] [Accepted: 09/11/2014] [Indexed: 11/20/2022] Open
Abstract
Little is known about the spatiotemporal coordination of mitochondrial metabolism in multicellular organisms in situ. Using intravital microscopy in live animals, we report that mitochondrial metabolism undergoes rapid and periodic oscillations under basal conditions. Notably, mitochondria in vivo behave as a network of functionally coupled oscillators, which maintain a high level of coordination throughout the tissue via the activity of gap junctions. These findings reveal a unique aspect of the relationship between tissue architecture and self-organization of mitochondrial metabolism in vivo.
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28
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Lee H, Yoon Y. Transient contraction of mitochondria induces depolarization through the inner membrane dynamin OPA1 protein. J Biol Chem 2014; 289:11862-11872. [PMID: 24627489 DOI: 10.1074/jbc.m113.533299] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Dynamin-related membrane remodeling proteins regulate mitochondrial morphology by mediating fission and fusion. Although mitochondrial morphology is considered an important factor in maintaining mitochondrial function, a direct mechanistic link between mitochondrial morphology and function has not been defined. We report here a previously unrecognized cellular process of transient contraction of the mitochondrial matrix. Importantly, we found that this transient morphological contraction of mitochondria is accompanied by a reversible loss or decrease of inner membrane potential. Fission deficiency greatly amplified this phenomenon, which functionally exhibited an increase of inner membrane proton leak. We found that electron transport activity is necessary for the morphological contraction of mitochondria. Furthermore, we discovered that silencing the inner membrane-associated dynamin optic atrophy 1 (OPA1) in fission deficiency prevented mitochondrial depolarization and decreased proton leak without blocking mitochondrial contraction, indicating that OPA1 is a factor in coupling matrix contraction to mitochondrial depolarization. Our findings show that transient matrix contraction is a novel cellular mechanism regulating mitochondrial activity through the function of the inner membrane dynamin OPA1.
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Affiliation(s)
- Hakjoo Lee
- Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30912
| | - Yisang Yoon
- Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30912.
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29
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Dikov D, Bereiter-Hahn J. Inner membrane dynamics in mitochondria. J Struct Biol 2013; 183:455-466. [DOI: 10.1016/j.jsb.2013.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 05/28/2013] [Accepted: 06/07/2013] [Indexed: 01/04/2023]
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30
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Zand K, Pham T, Davila A, Wallace DC, Burke PJ. Nanofluidic platform for single mitochondria analysis using fluorescence microscopy. Anal Chem 2013; 85:6018-25. [PMID: 23678849 DOI: 10.1021/ac4010088] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using nanofluidic channels in PDMS of cross section 500 nm × 2 μm, we demonstrate the trapping and interrogation of individual, isolated mitochondria. Fluorescence labeling demonstrates the immobilization of mitochondria at discrete locations along the channel. Interrogation of mitochondrial membrane potential with different potential sensitive dyes (JC-1 and TMRM) indicates the trapped mitochondria are vital in the respiration buffer. Fluctuations of the membrane potential can be observed at the single mitochondrial level. A variety of chemical challenges can be delivered to each individual mitochondrion in the nanofluidic system. As sample demonstrations, increases in the membrane potential are seen upon introduction of OXPHOS substrates into the nanofluidic channel. Introduction of Ca(2+) into the nanochannels induces mitochondrial membrane permeabilization (MMP), leading to depolarization, observed at the single mitochondrial level. A variety of applications in cancer biology, stem cell biology, apoptosis studies, and high throughput functional metabolomics studies can be envisioned using this technology.
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Affiliation(s)
- Katayoun Zand
- Integrated Nanosystem Research Facility, Electrical Engineering and Computer Science, University of California, Irvine, Irvine, California, USA
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31
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OPA1 promotes pH flashes that spread between contiguous mitochondria without matrix protein exchange. EMBO J 2013; 32:1927-40. [PMID: 23714779 PMCID: PMC3981180 DOI: 10.1038/emboj.2013.124] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 04/19/2013] [Indexed: 01/13/2023] Open
Abstract
The chemical nature and functional significance of mitochondrial flashes associated with fluctuations in mitochondrial membrane potential is unclear. Using a ratiometric pH probe insensitive to superoxide, we show that flashes reflect matrix alkalinization transients of ∼0.4 pH units that persist in cells permeabilized in ion-free solutions and can be evoked by imposed mitochondrial depolarization. Ablation of the pro-fusion protein Optic atrophy 1 specifically abrogated pH flashes and reduced the propagation of matrix photoactivated GFP (paGFP). Ablation or invalidation of the pro-fission Dynamin-related protein 1 greatly enhanced flash propagation between contiguous mitochondria but marginally increased paGFP matrix diffusion, indicating that flashes propagate without matrix content exchange. The pH flashes were associated with synchronous depolarization and hyperpolarization events that promoted the membrane potential equilibration of juxtaposed mitochondria. We propose that flashes are energy conservation events triggered by the opening of a fusion pore between two contiguous mitochondria of different membrane potentials, propagating without matrix fusion to equilibrate the energetic state of connected mitochondria. Mitochondrial fusion events and transient changes in matrix pH linked to membrane depolarization are found to underlie mitochondrial flashes, whose propagation may help equilibrate energy states between connected mitochondria.
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32
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Yano T, Lian CS, Arimitsu T, Yamanaka R, Afroundeh R, Shirakawa K, Yunoki T. Oscillation of oxygenation in skeletal muscle at rest and in light exercise. ACTA PHYSIOLOGICA HUNGARICA 2013; 100:312-20. [PMID: 23681050 DOI: 10.1556/aphysiol.100.2013.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The aim of the present study was to compare the frequency of oxygenation determined in the vastus lateralis by near-infrared spectroscopy (NIRS) in light exercise with that at rest. A subject rested in a recumbent position for 5 min and changed body position to a sitting position on a cycle ergometer for 9 min. Then exercise with low intensity (work rate of 60% of maximal oxygen uptake) was carried out for 30 min. Total hemoglobin and myoglobin (THb/Mb) suddenly decreased after the start of exercise and gradually increased for 6 min. Oxygenated hemoglobin and myoglobin (Hb/MbO2) suddenly decreased and returned to a steady-state after the start of exercise. The difference between Hb/MbO2 and THb/Mb showed a sudden decrease and then a steady-state. This difference was analyzed by fast Fourier transform. The peak frequencies of the power spectrum density (PSD) were 0.0169 ± 0.0076 Hz at rest and 0.0117 ± 0.0042 Hz in exercise. The peak frequency of PSD was significantly decreased in exercise. In exercise, the range of frequencies was expanded. It is concluded that there are oscillations at rest as well as in exercise and that the frequency of peak PSD becomes lower in exercise than at rest.
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Affiliation(s)
- T Yano
- Hokkaido University Laboratory of Exercise Physiology, Faculty of Education Kita-ku, Sapporo Japan
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33
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Monteith A, Marszalec W, Chan P, Logan J, Yu W, Schwarz N, Wokosin D, Hockberger P. Imaging of mitochondrial and non-mitochondrial responses in cultured rat hippocampal neurons exposed to micromolar concentrations of TMRM. PLoS One 2013; 8:e58059. [PMID: 23483968 PMCID: PMC3587568 DOI: 10.1371/journal.pone.0058059] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 01/31/2013] [Indexed: 11/24/2022] Open
Abstract
Tetramethylrhodamine methyl ester (TMRM) is a fluorescent dye used to study mitochondrial function in living cells. Previously, we reported that TMRM effectively labeled mitochondria of neurons deep within mouse brain slices. Use of micromolar concentration of dye, which was required to get sufficient staining for two-photon imaging, resulted in typical fluctuations of TMRM. With prolonged exposure, we recorded additional responses in some neurons that included slow oscillations and propagating waves of fluorescence. (Note: We use the terms “fluctuation” to refer to a change in the fluorescent state of an individual mitochondrion, “oscillation” to refer to a localized change in fluorescence in the cytosol, and “wave” to refer to a change in cytosolic fluorescence that propagated within a cell. Use of these terms does not imply any underlying periodicity.) In this report we describe similar results using cultured rat hippocampal neurons. Prolonged exposure of cultures to 2.5 µM TMRM produced a spontaneous increase in fluorescence in some neurons, but not glial cells, after 45–60 minutes that was followed by slow oscillations, waves, and eventually apoptosis. Spontaneous increases in fluorescence were insensitive to high concentrations of FCCP (100 µM) and thapsigargin (10 µM) indicating that they originated, at least in part, from regions outside of mitochondria. The oscillations did not correlate with changes in intracellular Ca2+, but did correlate with differences in fluorescence lifetime of the dye. Fluorescence lifetime and one-photon ratiometric imaging of TMRM suggested that the spontaneous increase and subsequent oscillations were due to movement of dye between quenched (hydrophobic) and unquenched (hydrophilic) compartments. We propose that these movements may be correlates of intracellular events involved in early stages of apoptosis.
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Affiliation(s)
- Andrew Monteith
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - William Marszalec
- Department of Molecular Pharmacology and Biological Chemistry, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Philip Chan
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Juliette Logan
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Weiming Yu
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Nicholas Schwarz
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - David Wokosin
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Philip Hockberger
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
- * E-mail:
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34
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Cheng G, Kong RH, Zhang LM, Zhang JN. Mitochondria in traumatic brain injury and mitochondrial-targeted multipotential therapeutic strategies. Br J Pharmacol 2013; 167:699-719. [PMID: 23003569 DOI: 10.1111/j.1476-5381.2012.02025.x] [Citation(s) in RCA: 231] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Traumatic brain injury (TBI) is a major health and socioeconomic problem throughout the world. It is a complicated pathological process that consists of primary insults and a secondary insult characterized by a set of biochemical cascades. The imbalance between a higher energy demand for repair of cell damage and decreased energy production led by mitochondrial dysfunction aggravates cell damage. At the cellular level, the main cause of the secondary deleterious cascades is cell damage that is centred in the mitochondria. Excitotoxicity, Ca(2+) overload, reactive oxygen species (ROS), Bcl-2 family, caspases and apoptosis inducing factor (AIF) are the main participants in mitochondria-centred cell damage following TBI. Some preclinical and clinical results of mitochondria-targeted therapy show promise. Mitochondria- targeted multipotential therapeutic strategies offer new hope for the successful treatment of TBI and other acute brain injuries.
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Affiliation(s)
- Gang Cheng
- Neurosurgical Department, PLA Navy General Hospital, Beijing, China
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35
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36
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Santo-Domingo J, Demaurex N. Perspectives on: SGP symposium on mitochondrial physiology and medicine: the renaissance of mitochondrial pH. ACTA ACUST UNITED AC 2013; 139:415-23. [PMID: 22641636 PMCID: PMC3362525 DOI: 10.1085/jgp.201110767] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Jaime Santo-Domingo
- Department of Cell Physiology and Metabolism, University of Geneva, CH-1211 Geneva, Switzerland
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37
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Hosseini MJ, Shaki F, Ghazi-Khansari M, Pourahmad J. Toxicity of Arsenic (III) on Isolated Liver Mitochondria: A New Mechanistic Approach. IRANIAN JOURNAL OF PHARMACEUTICAL RESEARCH : IJPR 2013; 12:121-38. [PMID: 24250680 PMCID: PMC3813354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/29/2022]
Abstract
Arsenic exposure mainly through food and water has been shown to be associated with increased incidence of numerous cancers and non-cancer harmful health. It is also used in cancer chemotherapy and treatment of several cancer types due to its apoptogenic effects in the various cancer and normal cell lines. We have already reported that liver is the storage site and important target organ in As (III) toxicity and recently, it has been suggested that hepatic toxicity of arsenic could be resulted from impairment of the liver mitochondria. In this study, interaction of As (III) with freshly isolated rat mitochondria was investigated. We determined different mitochondrial toxicity factors as well as mitochondrial sources of ROS formation using specific substrates and inhibitors following addition of As (III) to the mitochondria. Our results showed that arsenic (III) increased mitochondrial ROS formation, lipid peroxidation and mitochondrial membrane potential collapse, cytochrome c release and mitochondrial swelling in a concentration dependent manner. Addition of As (III) in to the isolated mitochondria, inhibited complexes I and II leading to disruption of mitochondrial electron transfer chain, decreased mitochondrial ATP content and ROS formation.
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Affiliation(s)
- Mir-Jamal Hosseini
- Faculty of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Pharmacology and Toxicology, School of Pharmacy, Zanjan University of Medical Sciences, Zanjan, Iran. ,Student Research Committee, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Fatemeh Shaki
- Faculty of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Pharmacology and Toxicology, School of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran.
| | - Mahmoud Ghazi-Khansari
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences,Tehran, Iran.
| | - Jalal Pourahmad
- Faculty of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Corresponding author: E-mail:
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38
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Liu W, Zhou C. Corticosterone reduces brain mitochondrial function and expression of mitofusin, BDNF in depression-like rodents regardless of exercise preconditioning. Psychoneuroendocrinology 2012; 37:1057-70. [PMID: 22244747 DOI: 10.1016/j.psyneuen.2011.12.003] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 10/15/2011] [Accepted: 12/02/2011] [Indexed: 12/13/2022]
Abstract
Both chronic mild stress and an injection of corticosterone induce depression-like states in rodents. To further link mitochondrial dysfunction to the pathophysiology of major depression, here we describe two rat models of a depressive-like state induced by chronic unpredictable mild stress (CUMS) or corticosterone treatment (CORT). It is also a model that allows the simultaneous study of effects of exercise preconditioning on behavioral, electrophysiological, biochemical and molecular markers in the same animal. Exercise preconditioning ahead of CUMS and CORT treatment prevents many behavioral abnormalities resulted from CUMS. The changes in mitochondrial activity in brain and reduced expressions of superoxide dismutase (SOD1, SOD2), mitofusin (Mfn1, Mfn2) as well as brain-derived neurotrophic factor (BDNF) suggest that both CORT and CUMS may impair mitochondrial function and/or expressions of mitofusion and antioxidant enzymes that, in turn, may increase oxidative stress and reduce energy production in brain with depression-like behaviors. These findings suggest an underlying mechanism by which CORT, as well as CUMS, induces brain mitochondrial dysfunction that is associated with depressive-like states. Remarkably, physical exercise is identified as a helpful and preventive measure to promote mitochondrial function and expressions of mitofusin, BDNF and antioxidant enzymes in brain, so as to protect brain energy metabolism against CUMS, rather than the compound of corticosterone.
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Affiliation(s)
- Weina Liu
- Department of Health & Exercise Science, Tianjin University of Sport, Tianjin, China
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39
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Chen YB, Aon MA, Hsu YT, Soane L, Teng X, McCaffery JM, Cheng WC, Qi B, Li H, Alavian KN, Dayhoff-Brannigan M, Zou S, Pineda FJ, O'Rourke B, Ko YH, Pedersen PL, Kaczmarek LK, Jonas EA, Hardwick JM. Bcl-xL regulates mitochondrial energetics by stabilizing the inner membrane potential. ACTA ACUST UNITED AC 2011; 195:263-76. [PMID: 21987637 PMCID: PMC3198165 DOI: 10.1083/jcb.201108059] [Citation(s) in RCA: 166] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To promote cell survival, the antiapoptotic factor Bcl-xL both
inhibits Bax-induced mitochondrial outer membrane permeabilization and
stabilizes mitochondrial inner membrane ion flux and thus overall mitochondrial
energetic capacity. Mammalian Bcl-xL protein localizes to the outer mitochondrial
membrane, where it inhibits apoptosis by binding Bax and inhibiting Bax-induced
outer membrane permeabilization. Contrary to expectation, we found by electron
microscopy and biochemical approaches that endogenous Bcl-xL also
localized to inner mitochondrial cristae. Two-photon microscopy of cultured
neurons revealed large fluctuations in inner mitochondrial membrane potential
when Bcl-xL was genetically deleted or pharmacologically inhibited,
indicating increased total ion flux into and out of mitochondria. Computational,
biochemical, and genetic evidence indicated that Bcl-xL reduces
futile ion flux across the inner mitochondrial membrane to prevent a wasteful
drain on cellular resources, thereby preventing an energetic crisis during
stress. Given that F1FO–ATP synthase directly
affects mitochondrial membrane potential and having identified the mitochondrial
ATP synthase β subunit in a screen for Bcl-xL–binding
partners, we tested and found that Bcl-xL failed to protect β
subunit–deficient yeast. Thus, by bolstering mitochondrial energetic
capacity, Bcl-xL may contribute importantly to cell survival
independently of other Bcl-2 family proteins.
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Affiliation(s)
- Ying-Bei Chen
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
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40
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Keil VC, Funke F, Zeug A, Schild D, Müller M. Ratiometric high-resolution imaging of JC-1 fluorescence reveals the subcellular heterogeneity of astrocytic mitochondria. Pflugers Arch 2011; 462:693-708. [PMID: 21881871 PMCID: PMC3192276 DOI: 10.1007/s00424-011-1012-8] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 08/07/2011] [Indexed: 11/25/2022]
Abstract
Using the mitochondrial potential (ΔΨm) marker JC-1 (5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazolylcarbocyanine iodide) and high-resolution imaging, we functionally analyzed mitochondria in cultured rat hippocampal astrocytes. Ratiometric detection of JC-1 fluorescence identified mitochondria with high and low ΔΨm. Mitochondrial density was highest in the perinuclear region, whereas ΔΨm tended to be higher in peripheral mitochondria. Spontaneous ΔΨm fluctuations, representing episodes of increased energization, appeared in individual mitochondria or synchronized in mitochondrial clusters. They continued upon withdrawal of extracellular Ca2+, but were antagonized by dantrolene or 2-aminoethoxydiphenylborate (2-APB). Fluo-3 imaging revealed local cytosolic Ca2+ transients with similar kinetics that also were depressed by dantrolene and 2-APB. Massive cellular Ca2+ load or metabolic impairment abolished ΔΨm fluctuations, occasionally evoking heterogeneous mitochondrial depolarizations. The detected diversity and ΔΨm heterogeneity of mitochondria confirms that even in less structurally polarized cells, such as astrocytes, specialized mitochondrial subpopulations coexist. We conclude that ΔΨm fluctuations are an indication of mitochondrial viability and are triggered by local Ca2+ release from the endoplasmic reticulum. This spatially confined organelle crosstalk contributes to the functional heterogeneity of mitochondria and may serve to adapt the metabolism of glial cells to the activity and metabolic demand of complex neuronal networks. The established ratiometric JC-1 imaging—especially combined with two-photon microscopy—enables quantitative functional analyses of individual mitochondria as well as the comparison of mitochondrial heterogeneity in different preparations and/or treatment conditions.
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Affiliation(s)
- Vera C Keil
- DFG Research Center Molecular Physiology of the Brain, Humboldtallee 23, D-37073, Göttingen, Germany
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41
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Malyukin YV, Kavok NS, Borovoy IA, Pogrebnyak NL, Geraschenko AV. Estimation of luminescent properties of the derivatives of polymethine probes on their interaction with cells of different types. Biophysics (Nagoya-shi) 2011. [DOI: 10.1134/s0006350911020205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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42
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Li F, Qiu E, Dong Z, Liu R, Wu S, Yu S. Protection of flunarizine on cerebral mitochondria injury induced by cortical spreading depression under hypoxic conditions. J Headache Pain 2011; 12:47-53. [PMID: 21350793 PMCID: PMC3055997 DOI: 10.1007/s10194-011-0300-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 11/25/2010] [Indexed: 10/27/2022] Open
Abstract
A rat cortical spreading depression (CSD) model was established to explore whether cerebral mitochondria injury was induced by CSD under both normoxic and hypoxic conditions and whether flunarizine had a protective effect on cerebral mitochondria. SD rats, which were divided into seven groups, received treatment as follows: no intervention (control Group I); 1 M NaCl injections (Group II); 1 M KCl injections (Group III); intraperitoneal flunarizine (3 mg/kg) 30 min before KCl injections (Group IV); 14% O(2) inhalation before NaCl injections (Group V); 14% O(2) inhalation followed by KCl injections (Group VI); 14% O(2) inhalation and intraperitoneal flunarizine followed by KCl injections (Group VII). Following treatment, brains were removed for the analysis of mitochondria transmembrane potential (MMP) and oxidative respiratory function after recording the number, amplitude and duration of CSD. The duration of CSD was significantly longer in Group VI than that in Group III. The number and duration of CSD in Group VII was significantly lower than that in Group VI. MMP in Group VI was significantly lower than that in Group III, and MMP in Group VII was significantly higher than that in Group VI. State 4 respiration in Group VI was significantly higher than that in Group III, and state 3 respiration in Group VII was significantly higher than that in Group VI. Respiration control of rate in Group VII was also significantly higher than that in Group VI. Thus, we concluded that aggravated cerebral mitochondria injury might be attributed to CSD under hypoxic conditions. Flunarizine can alleviate such cerebral mitochondria injury under both normoxic and hypoxic conditions.
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Affiliation(s)
- Fengpeng Li
- Department of Neurology, Chinese PLA General Hospital, Beijing, 100853 China
| | - Enchao Qiu
- Department of Neurology, Chinese PLA General Hospital, Beijing, 100853 China
| | - Zhao Dong
- Department of Neurology, Chinese PLA General Hospital, Beijing, 100853 China
| | - Ruozhuo Liu
- Department of Neurology, Chinese PLA General Hospital, Beijing, 100853 China
| | - Shiwen Wu
- Department of Neurology, Chinese PLA General Hospital, Beijing, 100853 China
| | - Shengyuan Yu
- Department of Neurology, Chinese PLA General Hospital, Beijing, 100853 China
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Gilmer LK, Roberts KN, Joy K, Sullivan PG, Scheff SW. Early mitochondrial dysfunction after cortical contusion injury. J Neurotrauma 2010; 26:1271-80. [PMID: 19637966 DOI: 10.1089/neu.2008.0857] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Following traumatic brain injury, mitochondria sustain structural and functional impairment, which contributes to secondary damage that can continue for days after the initial injury. The present study investigated mitochondrial bioenergetic changes in the rat neocortex at 1 and 3 h after mild, moderate, and severe injuries. Brains from young adult Sprague-Dawley rats were harvested from the injured and contralateral cortex to assess possible changes in mitochondrial respiration abilities following a unilateral cortical contusion injury. Differential centrifugation was used to isolate synaptic and extrasynaptic mitochondria from cortical tissue. Bioenergetics was assessed using a Clark-type electrode and results were graphed as a function of injury severity and time post-injury. Respiration was significantly affected by all injury severity levels compared to uninjured tissue. Complex 1- and complex 2-driven respirations were affected proportionally to the severity of the injury, indicating that damage to mitochondria may occur on a gradient. Total oxygen utilization, respiratory control ratio, ATP production, and maximal respiration capabilities were all significantly decreased in the injured cortex at both 1 and 3 h post-trauma. Although mitochondria displayed bioenergetic deficits at 1 h following injury, damage was not exacerbated by 3 h. This study stresses the importance of early therapeutic intervention and suggests a window of approximately 1-3 h before greater dysfunction occurs.
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Affiliation(s)
- Lesley K Gilmer
- Sanders Brown Center on Aging, University of Kentucky, Lexington, KY 40536-0230, USA
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44
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Iotti S, Borsari M, Bendahan D. Oscillations in energy metabolism. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1353-61. [DOI: 10.1016/j.bbabio.2010.02.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 02/17/2010] [Accepted: 02/17/2010] [Indexed: 11/26/2022]
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45
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Effects of α-mangostin on mitochondrial energetic metabolism. Mitochondrion 2010; 10:151-7. [DOI: 10.1016/j.mito.2009.12.140] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 11/16/2009] [Accepted: 12/04/2009] [Indexed: 11/21/2022]
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46
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Mitochondrial chloride channels - What are they for? FEBS Lett 2010; 584:2085-92. [DOI: 10.1016/j.febslet.2010.01.035] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 01/11/2010] [Accepted: 01/19/2010] [Indexed: 11/21/2022]
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47
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Bereiter-Hahn J, Jendrach M. Mitochondrial dynamics. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 284:1-65. [PMID: 20875628 DOI: 10.1016/s1937-6448(10)84001-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mitochondrial dynamics is a key feature for the interaction of mitochondria with other organelles within a cell and also for the maintenance of their own integrity. Four types of mitochondrial dynamics are discussed: Movement within a cell and interactions with the cytoskeleton, fusion and fission events which establish coherence within the chondriome, the dynamic behavior of cristae and their components, and finally, formation and disintegration of mitochondria (mitophagy). Due to these essential functions, disturbed mitochondrial dynamics are inevitably connected to a variety of diseases. Localized ATP gradients, local control of calcium-based messaging, production of reactive oxygen species, and involvement of other metabolic chains, that is, lipid and steroid synthesis, underline that physiology not only results from biochemical reactions but, in addition, resides on the appropriate morphology and topography. These events and their molecular basis have been established recently and are the topic of this review.
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Affiliation(s)
- Jürgen Bereiter-Hahn
- Center of Excellence Macromolecular Complexes, Institute for Cell Biology and Neurosciences, Goethe University, Frankfurt am Main, Germany
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48
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Perdomo G, Hernández JA. Minimal models of electric potential oscillations in non-excitable membranes. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2009; 39:277-87. [PMID: 19763561 DOI: 10.1007/s00249-009-0537-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 08/21/2009] [Accepted: 08/26/2009] [Indexed: 10/20/2022]
Abstract
Sustained oscillations in the membrane potential have been observed in a variety of cellular and subcellular systems, including several types of non-excitable cells and mitochondria. For the plasma membrane, these electrical oscillations have frequently been related to oscillations in intracellular calcium. For the inner mitochondrial membrane, in several cases the electrical oscillations have been attributed to modifications in calcium dynamics. As an alternative, some authors have suggested that the sustained oscillations in the mitochondrial membrane potential induced by some metabolic intermediates depends on the direct effect of internal protons on proton conductance. Most theoretical models developed to interpret oscillations in the membrane potential integrate several transport and biochemical processes. Here we evaluate whether three simple dynamic models may constitute plausible representations of electric oscillations in non-excitable membranes. The basic mechanism considered in the derivation of the models is based upon evidence obtained by Hattori et al. for mitochondria and assumes that an ionic species (i.e., the proton) is transported via passive and active transport systems between an external and an internal compartment and that the ion affects the kinetic properties of transport by feedback regulation. The membrane potential is incorporated via its effects on kinetic properties. The dynamic properties of two of the models enable us to conclude that they may represent alternatives enabling description of the generation of electrical oscillations in membranes that depend on the transport of a single ionic species.
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Affiliation(s)
- Guillermo Perdomo
- Sección Biofísica, Facultad de Ciencias, Universidad de la República, Iguá esq. Mataojo, 11400, Montevideo, Uruguay
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49
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Mitochondrial dynamics in heart cells: Very low amplitude high frequency fluctuations in adult cardiomyocytes and flow motion in non beating Hl-1 cells. J Bioenerg Biomembr 2009; 41:195-214. [DOI: 10.1007/s10863-009-9214-x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Accepted: 03/18/2009] [Indexed: 01/21/2023]
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50
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A comparison of Zn2+- and Ca2+-triggered depolarization of liver mitochondria reveals no evidence of Zn2+-induced permeability transition. Cell Calcium 2009; 45:447-55. [PMID: 19349076 DOI: 10.1016/j.ceca.2009.03.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 02/28/2009] [Accepted: 03/03/2009] [Indexed: 01/27/2023]
Abstract
Intracellular Zn(2+) toxicity is associated with mitochondrial dysfunction. Zn(2+) depolarizes mitochondria in assays using isolated organelles as well as cultured cells. Some reports suggest that Zn(2+)-induced depolarization results from the opening of the mitochondrial permeability transition pore (mPTP). For a more detailed analysis of this relationship, we compared Zn(2+)-induced depolarization with the effects of Ca(2+) in single isolated rat liver mitochondria monitored with the potentiometric probe rhodamine 123. Consistent with previous work, we found that relatively low levels of Ca(2+) caused rapid, complete and irreversible loss of mitochondrial membrane potential, an effect that was diminished by classic inhibitors of mPT, including high Mg(2+), ADP and cyclosporine A. Zn(2+) also depolarized mitochondria, but only at relatively high concentrations. Furthermore Zn(2+)-induced depolarization was slower, partial and sometimes reversible, and was not affected by inhibitors of mPT. We also compared the effects of Ca(2+) and Zn(2+) in a calcein-retention assay. Consistent with the well-documented ability of Ca(2+) to induce mPT, we found that it caused rapid and substantial loss of matrix calcein. In contrast, calcein remained in Zn(2+)-treated mitochondria. Considered together, our results suggest that Ca(2+) and Zn(2+) depolarize mitochondria by considerably different mechanisms, that opening of the mPTP is not a direct consequence of Zn(2+)-induced depolarization, and that Zn(2+) is not a particularly potent mitochondrial inhibitor.
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