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Mikhailova MM, Surin AM, Sobolevsky A, Yelshanskaya M, Bolshakov AP. Boris Izrailevich Khodorov: Scientist and Teacher. NEUROCHEM J+ 2022. [DOI: 10.1134/s1819712422040171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Plotegher N, Filadi R, Pizzo P, Duchen MR. Excitotoxicity Revisited: Mitochondria on the Verge of a Nervous Breakdown. Trends Neurosci 2021; 44:342-351. [PMID: 33608137 DOI: 10.1016/j.tins.2021.01.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 12/03/2020] [Accepted: 01/08/2021] [Indexed: 12/30/2022]
Abstract
Excitotoxicity is likely to occur in pathological scenarios in which mitochondrial function is already compromised, shaping neuronal responses to glutamate. In fact, mitochondria sustain cell bioenergetics, tune intracellular Ca2+ dynamics, and regulate glutamate availability by using it as metabolic substrate. Here, we suggest the need to explore glutamate toxicity in the context of specific disease models in which it may occur, re-evaluating the impact of mitochondrial dysfunction on glutamate excitotoxicity. Our aim is to signpost new approaches, perhaps combining glutamate and pathways to rescue mitochondrial function, as therapeutic targets in neurological disorders.
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Affiliation(s)
| | - Riccardo Filadi
- Department of Biomedical Sciences, University of Padova, Padova, Italy; Neuroscience Institute, National Research Council (CNR), Padua, Italy
| | - Paola Pizzo
- Department of Biomedical Sciences, University of Padova, Padova, Italy; Neuroscience Institute, National Research Council (CNR), Padua, Italy
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, London, UK.
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Mironova GD, Pavlov EV. Mitochondrial Cyclosporine A-Independent Palmitate/Ca 2+-Induced Permeability Transition Pore (PA-mPT Pore) and Its Role in Mitochondrial Function and Protection against Calcium Overload and Glutamate Toxicity. Cells 2021; 10:cells10010125. [PMID: 33440765 PMCID: PMC7827677 DOI: 10.3390/cells10010125] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 12/29/2020] [Accepted: 12/30/2020] [Indexed: 11/16/2022] Open
Abstract
A sharp increase in the permeability of the mitochondrial inner membrane known as mitochondrial permeability transition (or mPT) occurs in mitochondria under the conditions of Ca2+ and ROS stress. Permeability transition can proceed through several mechanisms. The most common mechanism of mPT is based on the opening of a cyclosporine A (CSA)-sensitive protein channel in the inner membrane. In addition to the CSA-sensitive pathway, mPT can occur through the transient opening of lipid pores, emerging in the process of formation of palmitate/Ca2+ complexes. This pathway is independent of CSA and likely plays a protective role against Ca2+ and ROS toxicity. The review considers molecular mechanisms of formation and regulation of the palmitate/Ca2+-induced pores, which we designate as PA-mPT to distinguish it from the classical CSA-sensitive mPT. In the paper, we discuss conditions of its opening in the biological membranes, as well as its role in the physiological and pathophysiological processes. Additionally, we summarize data that indicate the involvement of PA-mPT in the protection of mitochondria against calcium overload and glutamate-induced degradation in neurons.
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Affiliation(s)
- Galina D. Mironova
- Institute of Theoretical and Experimental Biophysics, RAS, Pushchino, 142290 Moscow, Russia
- Correspondence:
| | - Evgeny V. Pavlov
- Department of Molecular Pathobiology, College of Dentistry, New York University, New York, NY 10010, USA;
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Boczek T, Radzik T, Ferenc B, Zylinska L. The Puzzling Role of Neuron-Specific PMCA Isoforms in the Aging Process. Int J Mol Sci 2019; 20:ijms20246338. [PMID: 31888192 PMCID: PMC6941135 DOI: 10.3390/ijms20246338] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 12/10/2019] [Accepted: 12/13/2019] [Indexed: 01/02/2023] Open
Abstract
The aging process is a physiological phenomenon associated with progressive changes in metabolism, genes expression, and cellular resistance to stress. In neurons, one of the hallmarks of senescence is a disturbance of calcium homeostasis that may have far-reaching detrimental consequences on neuronal physiology and function. Among several proteins involved in calcium handling, plasma membrane Ca2+-ATPase (PMCA) is the most sensitive calcium detector controlling calcium homeostasis. PMCA exists in four main isoforms and PMCA2 and PMCA3 are highly expressed in the brain. The overall effects of impaired calcium extrusion due to age-dependent decline of PMCA function seem to accumulate with age, increasing the susceptibility to neurotoxic insults. To analyze the PMCA role in neuronal cells, we have developed stable transfected differentiated PC12 lines with down-regulated PMCA2 or PMCA3 isoforms to mimic age-related changes. The resting Ca2+ increased in both PMCA-deficient lines affecting the expression of several Ca2+-associated proteins, i.e., sarco/endoplasmic Ca2+-ATPase (SERCA), calmodulin, calcineurin, GAP43, CCR5, IP3Rs, and certain types of voltage-gated Ca2+ channels (VGCCs). Functional studies also demonstrated profound changes in intracellular pH regulation and mitochondrial metabolism. Moreover, modification of PMCAs membrane composition triggered some adaptive processes to counterbalance calcium overload, but the reduction of PMCA2 appeared to be more detrimental to the cells than PMCA3.
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Affiliation(s)
- Tomasz Boczek
- Department of Molecular Neurochemistry, Medical University, 92-215 Lodz, Poland; (T.B.); (T.R.); (B.F.)
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Tomasz Radzik
- Department of Molecular Neurochemistry, Medical University, 92-215 Lodz, Poland; (T.B.); (T.R.); (B.F.)
| | - Bozena Ferenc
- Department of Molecular Neurochemistry, Medical University, 92-215 Lodz, Poland; (T.B.); (T.R.); (B.F.)
| | - Ludmila Zylinska
- Department of Molecular Neurochemistry, Medical University, 92-215 Lodz, Poland; (T.B.); (T.R.); (B.F.)
- Correspondence: ; Tel.: +48-42-272-5680
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Belosludtsev KN, Dubinin MV, Belosludtseva NV, Mironova GD. Mitochondrial Ca2+ Transport: Mechanisms, Molecular Structures, and Role in Cells. BIOCHEMISTRY. BIOKHIMIIA 2019; 84:593-607. [PMID: 31238859 DOI: 10.1134/s0006297919060026] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 03/18/2019] [Accepted: 03/19/2019] [Indexed: 11/29/2023]
Abstract
Mitochondria are among the most important cell organelles involved in the regulation of intracellular calcium homeostasis. During the last decade, a number of molecular structures responsible for the mitochondrial calcium transport have been identified including the mitochondrial Ca2+ uniporter (MCU), Na+/Ca2+ exchanger (NCLX), and Ca2+/H+ antiporter (Letm1). The review summarizes the data on the structure, regulation, and physiological role of such structures. The pathophysiological mechanism of Ca2+ transport through the cyclosporine A-sensitive mitochondrial permeability transition pore is discussed. An alternative mechanism for the mitochondrial pore opening, namely, formation of the lipid pore induced by saturated fatty acids, and its role in Ca2+ transport are described in detail.
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Affiliation(s)
- K N Belosludtsev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
- Mari State University, Yoshkar-Ola, 424000, Russia
| | - M V Dubinin
- Mari State University, Yoshkar-Ola, 424000, Russia
| | - N V Belosludtseva
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - G D Mironova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
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Hawrysh PJ, Buck LT. Mitochondrial matrix pH acidifies during anoxia and is maintained by the F 1F o-ATPase in anoxia-tolerant painted turtle cortical neurons. FEBS Open Bio 2019; 9:571-581. [PMID: 30984533 PMCID: PMC6443863 DOI: 10.1002/2211-5463.12612] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 01/18/2019] [Accepted: 02/05/2019] [Indexed: 12/19/2022] Open
Abstract
The western painted turtle (Chrysemys picta bellii) can survive extended periods of anoxia via a series of mechanisms that serve to reduce its energetic needs. Central to these mechanisms is the response of mitochondria, which depolarize in response to anoxia in turtle pyramidal neurons due to an influx of K+. It is currently unknown how mitochondrial matrix pH is affected by this response and we hypothesized that matrix pH acidifies during anoxia due to increased K+/H+ exchanger activity. Inhibition of K+/H+ exchange via quinine led to a collapse of mitochondrial membrane potential (Ψm) during oxygenated conditions in turtle cortical neurons, as indicated by rhodamine‐123 fluorescence, and this occurred twice as quickly during anoxia which indicates an elevation in K+ conductance. Mitochondrial matrix pH acidified during anoxia, as indicated by SNARF‐1 fluorescence imaged via confocal microscopy, and further acidification occurred during anoxia when the F1Fo‐ATPase was inhibited with oligomycin‐A, indicating that ΔpH collapse is prevented during anoxic conditions. Collectively, these results indicate that the mitochondrial proton electrochemical gradient is actively preserved during anoxia to prevent a collapse of Ψm and ΔpH.
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Affiliation(s)
| | - Leslie Thomas Buck
- Department of Cell and Systems Biology University of Toronto Canada.,Department of Ecology and Evolutionary Biology University of Toronto Canada
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Sharipov RR, Krasilnikova IA, Pinelis VG, Gorbacheva LR, Surin AM. Study of the Mechanism of the Neuron Sensitization to the Repeated Glutamate Challenge. BIOCHEMISTRY MOSCOW SUPPLEMENT SERIES A-MEMBRANE AND CELL BIOLOGY 2018. [DOI: 10.1134/s1990747818050057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Depp C, Bas-Orth C, Schroeder L, Hellwig A, Bading H. Synaptic Activity Protects Neurons Against Calcium-Mediated Oxidation and Contraction of Mitochondria During Excitotoxicity. Antioxid Redox Signal 2018; 29:1109-1124. [PMID: 28990420 DOI: 10.1089/ars.2017.7092] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AIMS Excitotoxicity triggered by extrasynaptic N-methyl-d-aspartate-type glutamate receptors has been implicated in many neurodegenerative conditions, including Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, and stroke. Mitochondrial calcium overload leading to mitochondrial dysfunction represents an early event in excitotoxicity. Neurons are rendered resistant to excitotoxicity by previous periods of synaptic activity that activates a nuclear calcium-driven neuroprotective gene program. This process, termed acquired neuroprotection, involves transcriptional repression of the mitochondrial calcium uniporter leading to a reduction in excitotoxcity-associated mitochondrial calcium load. As mitochondrial calcium and the production of reactive oxygen species may be linked, we monitored excitotoxicity-associated changes in the mitochondrial redox status using the ratiometric glutathione redox potential indicator, glutaredoxin 1 (GRX1)-redox-sensitive green fluorescent protein (roGFP)2, targeted to the mitochondrial matrix. Aim of this study was to investigate if suppression of oxidative stress underlies mitoprotection afforded by synaptic activity. RESULTS We found that synaptic activity protects primary rat hippocampal neurons against acute excitotoxicity-induced mitochondrial oxidative stress and mitochondrial contraction associated with it. Downregulation of the mitochondrial uniporter by genetic means mimics the protective effect of synaptic activity on mitochondrial redox status. These findings indicate that oxidative stress acts downstream of mitochondrial calcium overload in excitotoxicity. Innovation and Conclusion: We established mito-GRX1-roGFP2 as a reliable and sensitive tool to monitor rapid redox changes in mitochondria during excitotoxicity. Our results highlight the importance of developing means of blocking mitochondrial calcium overload for therapeutic targeting of oxidative stress and mitochondrial dysfunction in neurodegenerative diseases. Antioxid. Redox. Signal. 29, 1109-1124.
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Affiliation(s)
- Constanze Depp
- Department of Neurobiology, Interdisciplinary Center for Neurosciences, Heidelberg University , Heidelberg, Germany
| | - Carlos Bas-Orth
- Department of Neurobiology, Interdisciplinary Center for Neurosciences, Heidelberg University , Heidelberg, Germany
| | - Lisa Schroeder
- Department of Neurobiology, Interdisciplinary Center for Neurosciences, Heidelberg University , Heidelberg, Germany
| | - Andrea Hellwig
- Department of Neurobiology, Interdisciplinary Center for Neurosciences, Heidelberg University , Heidelberg, Germany
| | - Hilmar Bading
- Department of Neurobiology, Interdisciplinary Center for Neurosciences, Heidelberg University , Heidelberg, Germany
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Guidelines on experimental methods to assess mitochondrial dysfunction in cellular models of neurodegenerative diseases. Cell Death Differ 2017; 25:542-572. [PMID: 29229998 PMCID: PMC5864235 DOI: 10.1038/s41418-017-0020-4] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 10/06/2017] [Accepted: 10/12/2017] [Indexed: 01/22/2023] Open
Abstract
Neurodegenerative diseases are a spectrum of chronic, debilitating disorders characterised by the progressive degeneration and death of neurons. Mitochondrial dysfunction has been implicated in most neurodegenerative diseases, but in many instances it is unclear whether such dysfunction is a cause or an effect of the underlying pathology, and whether it represents a viable therapeutic target. It is therefore imperative to utilise and optimise cellular models and experimental techniques appropriate to determine the contribution of mitochondrial dysfunction to neurodegenerative disease phenotypes. In this consensus article, we collate details on and discuss pitfalls of existing experimental approaches to assess mitochondrial function in in vitro cellular models of neurodegenerative diseases, including specific protocols for the measurement of oxygen consumption rate in primary neuron cultures, and single-neuron, time-lapse fluorescence imaging of the mitochondrial membrane potential and mitochondrial NAD(P)H. As part of the Cellular Bioenergetics of Neurodegenerative Diseases (CeBioND) consortium (www.cebiond.org), we are performing cross-disease analyses to identify common and distinct molecular mechanisms involved in mitochondrial bioenergetic dysfunction in cellular models of Alzheimer’s, Parkinson’s, and Huntington’s diseases. Here we provide detailed guidelines and protocols as standardised across the five collaborating laboratories of the CeBioND consortium, with additional contributions from other experts in the field.
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Hou Y, Kitaguchi T, Kriszt R, Tseng YH, Raghunath M, Suzuki M. Ca 2+-associated triphasic pH changes in mitochondria during brown adipocyte activation. Mol Metab 2017; 6:797-808. [PMID: 28752044 PMCID: PMC5518710 DOI: 10.1016/j.molmet.2017.05.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/19/2017] [Accepted: 05/25/2017] [Indexed: 12/31/2022] Open
Abstract
Objective Brown adipocytes (BAs) are endowed with a high metabolic capacity for energy expenditure due to their high mitochondria content. While mitochondrial pH is dynamically regulated in response to stimulation and, in return, affects various metabolic processes, how mitochondrial pH is regulated during adrenergic stimulation-induced thermogenesis is unknown. We aimed to reveal the spatial and temporal dynamics of mitochondrial pH in stimulated BAs and the mechanisms behind the dynamic pH changes. Methods A mitochondrial targeted pH-sensitive protein, mito-pHluorin, was constructed and transfected to BAs. Transfected BAs were stimulated by an adrenergic agonist, isoproterenol. The pH changes in mitochondria were characterized by dual-color imaging with indicators that monitor mitochondrial membrane potential and heat production. The mechanisms of pH changes were studied by examining the involvement of electron transport chain (ETC) activity and Ca2+ profiles in mitochondria and the intracellular Ca2+ store, the endoplasmic reticulum (ER). Results A triphasic mitochondrial pH change in BAs upon adrenergic stimulation was revealed. In comparison to a thermosensitive dye, we reveal that phases 1 and 2 of the pH increase precede thermogenesis, while phase 3, characterized by a pH decrease, occurs during thermogenesis. The mechanism of pH increase is partially related to ETC. In addition, the pH increase occurs concurrently with an increase in mitochondrial Ca2+. This Ca2+ increase is contributed to by an influx from the ER, and it is further involved in mitochondrial pH regulation. Conclusions We demonstrate that an increase in mitochondrial pH is implicated as an early event in adrenergically stimulated BAs. We further suggest that this pH increase may play a role in the potentiation of thermogenesis. A triphasic mitochondrial pH changes in adrenergically stimulated BAs was revealed. Phases 1 and 2 of the pH increase precede thermogenesis. The pH increase is partially related to electron transport chain activity. Ca2+ was transmitted from endoplasmic reticulum to mitochondria during phase 1. The transmitted Ca2+ regulates pH increase in mitochondria.
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Key Words
- AMA, antimycin A
- BAs, brown adipocytes
- Brown adipocytes
- Ca2+
- Confocal microscopy
- EGTA, ethylene glycol tetraacetic acid
- ER, endoplasmic reticulum
- ETC, electron transport chain
- Endoplasmic reticulum
- FFAs, free fatty acids
- Fluorescence imaging
- IMS, intermembrane space
- ISO, isoproterenol
- MAM, mitochondria-associated ER membrane
- MCU, mitochondrial calcium uniporter
- Mitochondria-associated ER membrane
- Rot, rotenone
- SERCA, sarco/endoplasmic reticulum Ca2+-ATPase
- TG, thapsigargin
- TMRM, tetramethylrhodamine methyl ester
- UCP1, uncoupling protein 1
- β-AR, β-adrenergic receptor
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Affiliation(s)
- Yanyan Hou
- WASEDA Bioscience Research Institute in Singapore (WABIOS), 11 Biopolis Way, #05-02 Helios, Singapore 138667, Singapore
| | - Tetsuya Kitaguchi
- WASEDA Bioscience Research Institute in Singapore (WABIOS), 11 Biopolis Way, #05-02 Helios, Singapore 138667, Singapore; Comprehensive Research Organization, Waseda University, Tokyo, 162-0041, Japan
| | - Rókus Kriszt
- Department of Biomedical Engineering, National University of Singapore, 117583, Singapore; NUS Tissue Engineering Program, Life Sciences Institute, National University of Singapore, 117510, Singapore; Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, 117456, Singapore
| | - Yu-Hua Tseng
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA
| | - Michael Raghunath
- Department of Biomedical Engineering, National University of Singapore, 117583, Singapore; NUS Tissue Engineering Program, Life Sciences Institute, National University of Singapore, 117510, Singapore; Department of Biochemistry, Yong Loo Ling School of Medicine, National University of Singapore, 117597, Singapore
| | - Madoka Suzuki
- WASEDA Bioscience Research Institute in Singapore (WABIOS), 11 Biopolis Way, #05-02 Helios, Singapore 138667, Singapore; Comprehensive Research Organization, Waseda University, Tokyo, 162-0041, Japan; PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
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Rosselin M, Santo-Domingo J, Bermont F, Giacomello M, Demaurex N. L-OPA1 regulates mitoflash biogenesis independently from membrane fusion. EMBO Rep 2017; 18:451-463. [PMID: 28174208 PMCID: PMC5331265 DOI: 10.15252/embr.201642931] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 12/19/2016] [Accepted: 12/21/2016] [Indexed: 11/09/2022] Open
Abstract
Mitochondrial flashes mediated by optic atrophy 1 (OPA1) fusion protein are bioenergetic responses to stochastic drops in mitochondrial membrane potential (Δψm) whose origin is unclear. Using structurally distinct genetically encoded pH‐sensitive probes, we confirm that flashes are matrix alkalinization transients, thereby establishing the pH nature of these events, which we renamed “mitopHlashes”. Probes located in cristae or intermembrane space as verified by electron microscopy do not report pH changes during Δψm drops or respiratory chain inhibition. Opa1 ablation does not alter Δψm fluctuations but drastically decreases the efficiency of mitopHlash/Δψm coupling, which is restored by re‐expressing fusion‐deficient OPA1K301A and preserved in cells lacking the outer‐membrane fusion proteins MFN1/2 or the OPA1 proteases OMA1 and YME1L, indicating that mitochondrial membrane fusion and OPA1 proteolytic processing are dispensable. pH/Δψm uncoupling occurs early during staurosporine‐induced apoptosis and is mitigated by OPA1 overexpression, suggesting that OPA1 maintains mitopHlash competence during stress conditions. We propose that OPA1 stabilizes respiratory chain supercomplexes in a conformation that enables respiring mitochondria to compensate a drop in Δψm by an explosive matrix pH flash.
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Affiliation(s)
- Manon Rosselin
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Jaime Santo-Domingo
- Nestlé Institute of Health Sciences SA, EPFL Innovation Park, Lausanne, Switzerland
| | - Flavien Bermont
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | | | - Nicolas Demaurex
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
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Rueda CB, Llorente-Folch I, Traba J, Amigo I, Gonzalez-Sanchez P, Contreras L, Juaristi I, Martinez-Valero P, Pardo B, Del Arco A, Satrustegui J. Glutamate excitotoxicity and Ca2+-regulation of respiration: Role of the Ca2+ activated mitochondrial transporters (CaMCs). BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1158-1166. [PMID: 27060251 DOI: 10.1016/j.bbabio.2016.04.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 04/05/2016] [Accepted: 04/05/2016] [Indexed: 12/21/2022]
Abstract
Glutamate elicits Ca(2+) signals and workloads that regulate neuronal fate both in physiological and pathological circumstances. Oxidative phosphorylation is required in order to respond to the metabolic challenge caused by glutamate. In response to physiological glutamate signals, cytosolic Ca(2+) activates respiration by stimulation of the NADH malate-aspartate shuttle through Ca(2+)-binding to the mitochondrial aspartate/glutamate carrier (Aralar/AGC1/Slc25a12), and by stimulation of adenine nucleotide uptake through Ca(2+) binding to the mitochondrial ATP-Mg/Pi carrier (SCaMC-3/Slc25a23). In addition, after Ca(2+) entry into the matrix through the mitochondrial Ca(2+) uniporter (MCU), it activates mitochondrial dehydrogenases. In response to pathological glutamate stimulation during excitotoxicity, Ca(2+) overload, reactive oxygen species (ROS), mitochondrial dysfunction and delayed Ca(2+) deregulation (DCD) lead to neuronal death. Glutamate-induced respiratory stimulation is rapidly inactivated through a mechanism involving Poly (ADP-ribose) Polymerase-1 (PARP-1) activation, consumption of cytosolic NAD(+), a decrease in matrix ATP and restricted substrate supply. Glutamate-induced Ca(2+)-activation of SCaMC-3 imports adenine nucleotides into mitochondria, counteracting the depletion of matrix ATP and the impaired respiration, while Aralar-dependent lactate metabolism prevents substrate exhaustion. A second mechanism induced by excitotoxic glutamate is permeability transition pore (PTP) opening, which critically depends on ROS production and matrix Ca(2+) entry through the MCU. By increasing matrix content of adenine nucleotides, SCaMC-3 activity protects against glutamate-induced PTP opening and lowers matrix free Ca(2+), resulting in protracted appearance of DCD and protection against excitotoxicity in vitro and in vivo, while the lack of lactate protection during in vivo excitotoxicity explains increased vulnerability to kainite-induced toxicity in Aralar +/- mice. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Carlos B Rueda
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
| | - Irene Llorente-Folch
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
| | - Javier Traba
- Cardiovascular and Pulmonary Branch, NHLBI, NIH, 20892 Bethesda, MD, USA
| | - Ignacio Amigo
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 13560-970 São Paulo, Brazil
| | - Paloma Gonzalez-Sanchez
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
| | - Laura Contreras
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
| | - Inés Juaristi
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
| | - Paula Martinez-Valero
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
| | - Beatriz Pardo
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
| | - Araceli Del Arco
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain; Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla la Mancha, Toledo 45071, Spain
| | - Jorgina Satrustegui
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
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Surin AM, Gorbacheva LR, Savinkova IG, Sharipov RR, Khodorov BI, Pinelis VG. Study on ATP concentration changes in cytosol of individual cultured neurons during glutamate-induced deregulation of calcium homeostasis. BIOCHEMISTRY (MOSCOW) 2015; 79:146-57. [PMID: 24794730 DOI: 10.1134/s0006297914020084] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
For the first time, simultaneous monitoring of changes in the concentration of cytosolic ATP ([ATP]c), pH (pHc), and intracellular free Ca2+ concentration ([Ca2+]i) of the individual neurons challenged with toxic glutamate (Glu) concentrations was performed. To this end, the ATP-sensor AT1.03, which binds to ATP and therefore enhances the efficiency of resonance energy transfer between blue fluorescent protein (energy donor) and yellow-green fluorescent protein (energy acceptor), was expressed in cultured hippocampal neurons isolated from 1-2-day-old rat pups. Excitation of fluorescence in the acceptor protein allowed monitoring changes in pHc. Cells were loaded with fluorescent low-affinity Ca2+ indicators Fura-FF or X-rhod-FF to register [Ca2+]i. It was shown that Glu (20 µM, glycine 10 µM, Mg2+-free) produced a rapid acidification of the cytosol and decrease in [ATP]c. An approximately linear relationship (r(2) = 0.56) between the rate of [ATP]c decline and latency of glutamate-induced delayed calcium deregulation (DCD) was observed: higher rate of [ATP]c decrease corresponded to shorter DCD latency period. DCD began with a decrease in [ATP]c of as much as 15.9%. In the phase of high [Ca2+]i, the plateau of [ATP]c dropped to 10.4% compared to [ATP]c in resting neurons (100%). In the presence of the Na+/K+-ATPase inhibitor ouabain (0.5 mM), glutamate-induced reduction in [ATP]c in the phase of the high [Ca2+]i plateau was only 36.6%. Changes in [ATP]c, [Ca2+]i, mitochondrial potential, and pHc in calcium-free or sodium-free buffers, as well as in the presence of the inhibitor of Na+/K+-ATPase ouabain (0.5 mM), led us to suggest that in addition to increase in proton conductivity and decline in [ATP]c, one of the triggering factors of DCD might be a reversion of the neuronal plasma membrane Na+/Ca2+ exchange.
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Affiliation(s)
- A M Surin
- Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow, 125315, Russia.
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Mitochondrial ATP-Mg/Pi carrier SCaMC-3/Slc25a23 counteracts PARP-1-dependent fall in mitochondrial ATP caused by excitotoxic insults in neurons. J Neurosci 2015; 35:3566-81. [PMID: 25716855 DOI: 10.1523/jneurosci.2702-14.2015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Glutamate excitotoxicity is caused by sustained activation of neuronal NMDA receptors causing a large Ca(2+) and Na(+) influx, activation of poly(ADP ribose) polymerase-1 (PARP-1), and delayed Ca(2+) deregulation. Mitochondria undergo early changes in membrane potential during excitotoxicity, but their precise role in these events is still controversial. Using primary cortical neurons derived from mice, we show that NMDA exposure results in a rapid fall in mitochondrial ATP in neurons deficient in SCaMC-3/Slc25a23, a Ca(2+)-regulated mitochondrial ATP-Mg/Pi carrier. This fall is associated with blunted increases in respiration and a delayed decrease in cytosolic ATP levels, which are prevented by PARP-1 inhibitors or by SCaMC-3 activity promoting adenine nucleotide uptake into mitochondria. SCaMC-3 KO neurons show an earlier delayed Ca(2+) deregulation, and SCaMC-3-deficient mitochondria incubated with ADP or ATP-Mg had reduced Ca(2+) retention capacity, suggesting a failure to maintain matrix adenine nucleotides as a cause for premature delayed Ca(2+) deregulation. SCaMC-3 KO neurons have higher vulnerability to in vitro excitotoxicity, and SCaMC-3 KO mice are more susceptible to kainate-induced seizures, showing that early PARP-1-dependent fall in mitochondrial ATP levels, counteracted by SCaMC-3, is an early step in the excitotoxic cascade.
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15
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Mironova GD, Saris NEL, Belosludtseva NV, Agafonov AV, Elantsev AB, Belosludtsev KN. Involvement of palmitate/Ca2+(Sr2+)-induced pore in the cycling of ions across the mitochondrial membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:488-95. [PMID: 25450352 DOI: 10.1016/j.bbamem.2014.10.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 09/23/2014] [Accepted: 10/20/2014] [Indexed: 10/24/2022]
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16
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Culcasi M, Thétiot-Laurent S, Atteia A, Pietri S. Mitochondrial, acidic, and cytosolic pHs determination by ³¹P NMR spectroscopy: design of new sensitive targeted pH probes. Methods Mol Biol 2015; 1265:135-147. [PMID: 25634273 DOI: 10.1007/978-1-4939-2288-8_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
(31)P nuclear magnetic resonance (NMR) is a unique technique to monitor noninvasively the energetics of living systems at real time through the detection of a variety of phosphorylated metabolites. Using adequately designed α-aminophosphonates as external probes, we have shown earlier that (31)P NMR can also give access simultaneously to the accurate pH of cytosolic and acidic compartments in normal and stressed cultured cells or isolated perfused organs, a feature that was not possible using endogenous inorganic phosphate as the probe. More recently, we obtained a series of derivatives of these new pH probes that incorporate a triphenylphosphonium cation as a specific vector to the mitochondrion. Here, we describe the synthesis, (31)P NMR pH titrating properties in buffers, and application in cultures of the green alga Chlamydomonas reinhardtii of two of these mitochondria-targeted pH probes in comparison with one nonvectorized, yet still informative α-aminophosphonate.
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Affiliation(s)
- Marcel Culcasi
- UMR 7273, CNRS, Equipe Sondes Moléculaires en Biologie et Stress Oxydant, Centre scientifique de Saint-Jérôme, Institut de Chimie Radicalaire, Aix-Marseille Université, Service 522, Avenue Escadrille Normandie-Niemen, Marseille Cedex 20, 13397, France
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17
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Plasma membrane Ca2+-ATPase isoforms composition regulates cellular pH homeostasis in differentiating PC12 cells in a manner dependent on cytosolic Ca2+ elevations. PLoS One 2014; 9:e102352. [PMID: 25014339 PMCID: PMC4094512 DOI: 10.1371/journal.pone.0102352] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 06/17/2014] [Indexed: 12/14/2022] Open
Abstract
Plasma membrane Ca2+-ATPase (PMCA) by extruding Ca2+ outside the cell, actively participates in the regulation of intracellular Ca2+ concentration. Acting as Ca2+/H+ counter-transporter, PMCA transports large quantities of protons which may affect organellar pH homeostasis. PMCA exists in four isoforms (PMCA1-4) but only PMCA2 and PMCA3, due to their unique localization and features, perform more specialized function. Using differentiated PC12 cells we assessed the role of PMCA2 and PMCA3 in the regulation of intracellular pH in steady-state conditions and during Ca2+ overload evoked by 59 mM KCl. We observed that manipulation in PMCA expression elevated pHmito and pHcyto but only in PMCA2-downregulated cells higher mitochondrial pH gradient (ΔpH) was found in steady-state conditions. Our data also demonstrated that PMCA2 or PMCA3 knock-down delayed Ca2+ clearance and partially attenuated cellular acidification during KCl-stimulated Ca2+ influx. Because SERCA and NCX modulated cellular pH response in neglectable manner, and all conditions used to inhibit PMCA prevented KCl-induced pH drop, we considered PMCA2 and PMCA3 as mainly responsible for transport of protons to intracellular milieu. In steady-state conditions, higher TMRE uptake in PMCA2-knockdown line was driven by plasma membrane potential (Ψp). Nonetheless, mitochondrial membrane potential (Ψm) in this line was dissipated during Ca2+ overload. Cyclosporin and bongkrekic acid prevented Ψm loss suggesting the involvement of Ca2+-driven opening of mitochondrial permeability transition pore as putative underlying mechanism. The findings presented here demonstrate a crucial role of PMCA2 and PMCA3 in regulation of cellular pH and indicate PMCA membrane composition important for preservation of electrochemical gradient.
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Song DH, Park J, Maurer LL, Lu W, Philbert MA, Sastry AM. Biophysical significance of the inner mitochondrial membrane structure on the electrochemical potential of mitochondria. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:062723. [PMID: 24483502 PMCID: PMC4315510 DOI: 10.1103/physreve.88.062723] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Indexed: 05/29/2023]
Abstract
The available literature supports the hypothesis that the morphology of the inner mitochondrial membrane is regulated by different energy states, that the three-dimensional morphology of cristae is dynamic, and that both are related to biochemical function. Examination of the correlation between the inner mitochondrial membrane (IMM) structure and mitochondrial energetic function is critical to an understanding of the links between mesoscale morphology and function in progressive mitochondrial dysfunction such as aging, neurodegeneration, and disease. To investigate this relationship, we develop a model to examine the effects of three-dimensional IMM morphology on the electrochemical potential of mitochondria. The two-dimensional axisymmetric finite element method is used to simulate mitochondrial electric potential and proton concentration distribution. This simulation model demonstrates that the proton motive force (Δp) produced on the membranes of cristae can be higher than that on the inner boundary membrane. The model also shows that high proton concentration in cristae can be induced by the morphology-dependent electric potential gradient along the outer side of the IMM. Furthermore, simulation results show that a high Δp is induced by the large surface-to-volume ratio of an individual crista, whereas a high capacity for ATP synthesis can primarily be achieved by increasing the surface area of an individual crista. The mathematical model presented here provides compelling support for the idea that morphology at the mesoscale is a significant driver of mitochondrial function.
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Affiliation(s)
- Dong Hoon Song
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Jonghyun Park
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Laura L Maurer
- Toxicology Program, School of Public Health, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Wei Lu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Martin A Philbert
- Toxicology Program, School of Public Health, University of Michigan, Ann Arbor, Michigan 48109, USA
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Culcasi M, Casano G, Lucchesi C, Mercier A, Clément JL, Pique V, Michelet L, Krieger-Liszkay A, Robin M, Pietri S. Synthesis and Biological Characterization of New Aminophosphonates for Mitochondrial pH Determination by 31P NMR Spectroscopy. J Med Chem 2013; 56:2487-99. [DOI: 10.1021/jm301866e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Marcel Culcasi
- Aix-Marseille Université, CNRS UMR 7273, Equipe Sondes Moléculaires en Biologie et
Stress Oxydant, Institut de Chimie Radicalaire, Marseille, France
| | - Gilles Casano
- Aix-Marseille Université, CNRS UMR 7273, Equipe Sondes Moléculaires en Biologie et
Stress Oxydant, Institut de Chimie Radicalaire, Marseille, France
| | - Céline Lucchesi
- Aix-Marseille Université, CNRS UMR 7273, Equipe Sondes Moléculaires en Biologie et
Stress Oxydant, Institut de Chimie Radicalaire, Marseille, France
| | - Anne Mercier
- Aix-Marseille Université, CNRS UMR 7273, Equipe Sondes Moléculaires en Biologie et
Stress Oxydant, Institut de Chimie Radicalaire, Marseille, France
| | - Jean-Louis Clément
- Aix-Marseille Université, CNRS UMR 7273, Equipe Sondes Moléculaires en Biologie et
Stress Oxydant, Institut de Chimie Radicalaire, Marseille, France
| | - Valérie Pique
- Aix-Marseille Université, CNRS UMR 7273, Equipe Sondes Moléculaires en Biologie et
Stress Oxydant, Institut de Chimie Radicalaire, Marseille, France
| | - Laure Michelet
- CNRS UMR 8221, Institut de Biologie et de Technologie de Saclay (iBiTec-S),
CEA Saclay, Gif-sur-Yvette, France
| | - Anja Krieger-Liszkay
- CNRS UMR 8221, Institut de Biologie et de Technologie de Saclay (iBiTec-S),
CEA Saclay, Gif-sur-Yvette, France
| | - Maxime Robin
- Aix-Marseille Université, CNRS UMR 7273, Equipe Sondes Moléculaires en Biologie et
Stress Oxydant, Institut de Chimie Radicalaire, Marseille, France
| | - Sylvia Pietri
- Aix-Marseille Université, CNRS UMR 7273, Equipe Sondes Moléculaires en Biologie et
Stress Oxydant, Institut de Chimie Radicalaire, Marseille, France
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20
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Poburko D, Demaurex N. Regulation of the mitochondrial proton gradient by cytosolic Ca²⁺ signals. Pflugers Arch 2012; 464:19-26. [PMID: 22526460 DOI: 10.1007/s00424-012-1106-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 04/02/2012] [Indexed: 12/16/2022]
Abstract
Mitochondria convert the energy stored in carbohydrate and fat into ATP molecules that power enzymatic reactions within cells, and this process influences cellular calcium signals in several ways. By providing ATP to calcium pumps at the plasma and intracellular membranes, mitochondria power the calcium gradients that drive the release of Ca²⁺ from stores and the entry of Ca²⁺ across plasma membrane channels. By taking up and subsequently releasing calcium ions, mitochondria determine the spatiotemporal profile of cellular Ca²⁺ signals and the activity of Ca²⁺-regulated proteins, including Ca²⁺ entry channels that are themselves part of the Ca²⁺ circuitry. Ca²⁺ elevations in the mitochondrial matrix, in turn, activate Ca²⁺-dependent enzymes that boost the respiratory chain, increasing the ability of mitochondria to buffer calcium ions. Mitochondria are able to encode and decode Ca²⁺ signals because the respiratory chain generates an electrochemical gradient for protons across the inner mitochondrial membrane. This proton motive force (Δp) drives the activity of the ATP synthase and has both an electrical component, the mitochondrial membrane potential (ΔΨ(m)), and a chemical component, the mitochondrial proton gradient (ΔpH(m)). ΔΨ(m) contributes about 190 mV to Δp and drives the entry of Ca²⁺ across a recently identified Ca²⁺-selective channel known as the mitochondrial Ca²⁺ uniporter. ΔpH(m) contributes ~30 mV to Δp and is usually ignored or considered a minor component of mitochondria respiratory state. However, the mitochondrial proton gradient is an essential component of the chemiosmotic theory formulated by Peter Mitchell in 1961 as ΔpH(m) sustains the entry of substrates and metabolites required for the activity of the respiratory chain and drives the activity of electroneutral ion exchangers that allow mitochondria to maintain their osmolarity and volume. In this review, we summarize the mechanisms that regulate the mitochondrial proton gradient and discuss how thermodynamic concepts derived from measurements in purified mitochondria can be reconciled with our recent findings that mitochondria have high proton permeability in situ and that ΔpH(m) decreases during mitochondrial Ca²⁺ elevations.
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Affiliation(s)
- Damon Poburko
- Department of Biomedical Physiology & Kinesiology, Simon Fraser University, Vancouver, BC, Canada
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21
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Abstract
In neurons exposed to glutamate, Ca²⁺ influx triggers intracellular Zn²⁺ release via an as yet unclear mechanism. As glutamate induces a Ca²⁺-dependent cytosolic acidification, the present work tested the relationships among intracellular Ca²⁺ concentration ([Ca²⁺](i)), intracellular pH (pH(i) ), and [Zn²⁺](i). Cultured hippocampal neurons were exposed to glutamate and glycine (Glu/Gly), while [Zn²⁺](i), [Ca²⁺](i) and pH(i) were monitored using FluoZin-3, Fura2-FF, and 2',7'-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein, respectively. Glu/Gly applications decreased pH(i) to 6.1 and induced intracellular Zn²⁺ release in a Ca²⁺-dependent manner, as expected. The pH(i) drop reduced the affinity of FluoZin-3 and Fura-2-FF for Zn²⁺. The rate of Glu/Gly-induced [Zn²⁺](i) increase was not correlated with the rate of [Ca²⁺](i) increase. Instead, the extent of [Zn²⁺](i) elevations corresponded well to the rate of pH(i) drop. Namely, [Zn²⁺](i) increased more in more highly acidified neurons. Inhibiting the mechanisms responsible for the Ca²⁺-dependent pH(i) drop (plasmalemmal Ca²⁺ pump and mitochondria) counteracted the Glu/Gly-induced intracellular Zn²⁺ release. Alkaline pH (8.5) suppressed Glu/Gly-induced intracellular Zn²⁺ release whereas acidic pH (6.0) enhanced it. A pH(i) drop to 6.0 (without any Ca²⁺ influx or glutamate receptor activation) led to intracellular Zn²⁺ release; the released Zn²⁺ (free Zn²⁺ plus Zn²⁺) bound to Fura-2FF and FluoZin-3) reached 1 μM.
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Affiliation(s)
- Lech Kiedrowski
- Departments of Psychiatry and Pharmacology, The Psychiatric Institute, The University of Illinois at Chicago, Chicago, Illinois 60612, USA.
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Mironova GD, Belosludtsev KN, Surin AM, Trudovishnikov AS, Belosludtseva NV, Pinelis VG, Krasilnikova IA, Khodorov BI. Mitochondrial lipid pore in the mechanism of glutamate-induced calcium deregulation of brain neurons. BIOCHEMISTRY (MOSCOW) SUPPLEMENT SERIES A: MEMBRANE AND CELL BIOLOGY 2012; 6:45-55. [DOI: 10.1134/s1990747811060080] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
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Zhang Z, Nguyen KT, Barrett EF, David G. Vesicular ATPase inserted into the plasma membrane of motor terminals by exocytosis alkalinizes cytosolic pH and facilitates endocytosis. Neuron 2011; 68:1097-108. [PMID: 21172612 DOI: 10.1016/j.neuron.2010.11.035] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2010] [Indexed: 01/29/2023]
Abstract
Key components of vesicular neurotransmitter release, such as Ca(2+) influx and membrane recycling, are affected by cytosolic pH. We measured the pH-sensitive fluorescence of Yellow Fluorescent Protein transgenically expressed in mouse motor nerve terminals, and report that Ca(2+) influx elicited by action potential trains (12.5-100 Hz) evokes a biphasic pH change: a brief acidification (∼ 13 nM average peak increase in [H(+)]), followed by a prolonged alkalinization (∼ 30 nM peak decrease in [H(+)]) that outlasts the stimulation train. The alkalinization is selectively eliminated by blocking vesicular exocytosis with botulinum neurotoxins, and is prolonged by the endocytosis-inhibitor dynasore. Blocking H(+) pumping by vesicular H(+)-ATPase (with folimycin or bafilomycin) suppresses stimulation-induced alkalinization and reduces endocytotic uptake of FM1-43. These results suggest that H(+)-ATPase, known to transfer cytosolic H(+) into prefused vesicles, continues to extrude cytosolic H(+) after being exocytotically incorporated into the plasma membrane. The resulting cytosolic alkalinization may facilitate vesicular endocytosis.
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Affiliation(s)
- Zhongsheng Zhang
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
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Poburko D, Santo-Domingo J, Demaurex N. Dynamic regulation of the mitochondrial proton gradient during cytosolic calcium elevations. J Biol Chem 2011; 286:11672-84. [PMID: 21224385 PMCID: PMC3064219 DOI: 10.1074/jbc.m110.159962] [Citation(s) in RCA: 243] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Mitochondria extrude protons across their inner membrane to generate the mitochondrial membrane potential (ΔΨm) and pH gradient (ΔpHm) that both power ATP synthesis. Mitochondrial uptake and efflux of many ions and metabolites are driven exclusively by ΔpHm, whose in situ regulation is poorly characterized. Here, we report the first dynamic measurements of ΔpHm in living cells, using a mitochondrially targeted, pH-sensitive YFP (SypHer) combined with a cytosolic pH indicator (5-(and 6)-carboxy-SNARF-1). The resting matrix pH (∼7.6) and ΔpHm (∼0.45) of HeLa cells at 37 °C were lower than previously reported. Unexpectedly, mitochondrial pH and ΔpHm decreased during cytosolic Ca2+ elevations. The drop in matrix pH was due to cytosolic acid generated by plasma membrane Ca2+-ATPases and transmitted to mitochondria by Pi/H+ symport and K+/H+ exchange, whereas the decrease in ΔpHm reflected the low H+-buffering power of mitochondria (∼5 mm, pH 7.8) compared with the cytosol (∼20 mm, pH 7.4). Upon agonist washout and restoration of cytosolic Ca2+ and pH, mitochondria alkalinized and ΔpHm increased. In permeabilized cells, a decrease in bath pH from 7.4 to 7.2 rapidly decreased mitochondrial pH, whereas the addition of 10 μm Ca2+ caused a delayed and smaller alkalinization. These findings indicate that the mitochondrial matrix pH and ΔpHm are regulated by opposing Ca2+-dependent processes of stimulated mitochondrial respiration and cytosolic acidification.
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Affiliation(s)
- Damon Poburko
- Department of Cell Physiology and Metabolism, University of Geneva Medical School, Geneva, Switzerland
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Storozhevykh TP, Senilova YE, Brustovetsky T, Pinelis VG, Brustovetsky N. Neuroprotective Effect of KB-R7943 Against Glutamate Excitotoxicity is Related to Mild Mitochondrial Depolarization. Neurochem Res 2009; 35:323-35. [DOI: 10.1007/s11064-009-0058-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2009] [Indexed: 01/08/2023]
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Chinopoulos C, Adam-Vizi V. Mitochondria as ATP consumers in cellular pathology. Biochim Biophys Acta Mol Basis Dis 2009; 1802:221-7. [PMID: 19715757 DOI: 10.1016/j.bbadis.2009.08.008] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 07/17/2009] [Accepted: 08/17/2009] [Indexed: 12/21/2022]
Abstract
ATP provided by oxidative phosphorylation supports highly complex and energetically expensive cellular processes. Yet, in several pathological settings, mitochondria could revert to ATP consumption, aggravating an existing cellular pathology. Here we review (i) the pathological conditions leading to ATP hydrolysis by the reverse operation of the mitochondrial F(o)F(1)-ATPase, (ii) molecular and thermodynamic factors influencing the directionality of the F(o)F(1)-ATPase, (iii) the role of the adenine nucleotide translocase as the intermediary adenine nucleotide flux pathway between the cytosol and the mitochondrial matrix when mitochondria become ATP consumers, (iv) the role of the permeability transition pore in bypassing the ANT, thereby allowing the flux of ATP directly to the hydrolyzing F(o)F(1)-ATPase, (v) the impact of the permeability transition pore on glycolytic ATP production, and (vi) endogenous and exogenous interventions for limiting ATP hydrolysis by the mitochondrial F(o)F(1)-ATPase.
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Affiliation(s)
- Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Neurobiochemical Group, Hungarian Academy of Sciences, Budapest, Hungary
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Li V, Brustovetsky T, Brustovetsky N. Role of cyclophilin D-dependent mitochondrial permeability transition in glutamate-induced calcium deregulation and excitotoxic neuronal death. Exp Neurol 2009; 218:171-82. [PMID: 19236863 PMCID: PMC2710407 DOI: 10.1016/j.expneurol.2009.02.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 02/05/2009] [Accepted: 02/07/2009] [Indexed: 11/29/2022]
Abstract
In the present study we tested the hypothesis that the cyclophilin D-dependent (CyD) mitochondrial permeability transition (CyD-mPT) plays an important role in glutamate-triggered delayed calcium deregulation (DCD) and excitotoxic neuronal death. We used cultured cortical neurons from wild-type C57BL/6 and cyclophilin D-knockout mice (Ppif(-/-)). Induction of the mPT was identified by following the rapid secondary acidification of mitochondrial matrices monitored with mitochondrially targeted pH-sensitive yellow fluorescent protein. Suppression of the CyD-mPT due to genetic CyD ablation deferred DCD and mitochondrial depolarization, and increased the survival rate after exposure of neurons to 10 microM glutamate, but not to 100 microM glutamate. Ca(2+) influx into Ppif(-/-) neurons was not diminished in comparison with WT neurons judging by (45)Ca accumulation. In both types of neurons, 100 microM glutamate produced greater Ca(2+) influx than 10 microM glutamate. We hypothesize that greater Ca(2+) influx produced by higher glutamate rapidly triggered the CyD-independent mPT in both WT and Ppif(-/-) neurons equalizing their responses to supra-physiologic excitotoxic insults. In neurons exposed to moderate but pathophysiologically-relevant glutamate concentrations, an induction of the CyD-mPT appears to play an important role in mitochondrial injury contributing to DCD and cell death.
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Affiliation(s)
- Viacheslav Li
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | - Tatiana Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | - Nickolay Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN 46202, USA
- Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis IN 46202, USA
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Gerencser AA, Mark KA, Hubbard AE, Divakaruni AS, Mehrabian Z, Nicholls DG, Polster BM. Real-time visualization of cytoplasmic calpain activation and calcium deregulation in acute glutamate excitotoxicity. J Neurochem 2009; 110:990-1004. [PMID: 19493161 DOI: 10.1111/j.1471-4159.2009.06194.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Although calpain (EC 3.4.22) protease activation was suggested to contribute to excitotoxic delayed calcium deregulation (DCD) via proteolysis of Na+/Ca2+ exchanger 3 (NCX3), cytoplasmic calpain activation in relation to DCD has never been visualized in real-time. We employed a calpain fluorescence resonance energy transfer substrate to simultaneously image calpain activation and calcium deregulation in live cortical neurons. A calpain inhibitor-sensitive decline in fluorescence resonance energy transfer was observed at 39 +/- 5 min after the occurrence of DCD in neurons exposed to continuous glutamate (100 microM). Inhibition of calpain by calpeptin did not delay the onset of DCD, recovery from DCD-like reversible calcium elevations, or cell death despite inhibiting alpha-spectrin processing by > 90%. NCXs reversed during glutamate exposure, the NCX antagonist KB-R7943 prolonged the time to DCD, and significant NCX3 cleavage following 90 min of glutamate exposure was not observed. Our findings suggest that robust calpain activation associated with acute glutamate toxicity occurs only after a sustained loss in calcium homeostasis. Processing of NCX3 or other calpain substrates is unlikely to be the primary cause of acute excitotoxicity in cortical neurons. However, a role for calpain as a contributing factor or in response to milder glutamate insults is not excluded.
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29
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Nicholls DG. Mitochondrial calcium function and dysfunction in the central nervous system. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1416-24. [PMID: 19298790 DOI: 10.1016/j.bbabio.2009.03.010] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2008] [Revised: 03/09/2009] [Accepted: 03/10/2009] [Indexed: 12/17/2022]
Abstract
The ability of isolated brain mitochondria to accumulate, store and release calcium has been extensively characterized. Extrapolation to the intact neuron led to predictions that the in situ mitochondria would reversibly accumulate Ca(2+) when the concentration of the cation in the vicinity of the mitochondria rose above the 'set-point' at which uptake and efflux were in balance, storing Ca(2+) as a complex with phosphate, and slowly releasing the cation when plasma membrane ion pumps lowered the cytoplasmic free Ca(2+). Excessive accumulation of the cation was predicted to lead to activation of the permeability transition, with catastrophic consequences for the neuron. Each of these predictions has been confirmed with intact neurons, and there is convincing evidence for the permeability transition in cellular Ca(2+) overload associated with glutamate excitotoxicity and stroke, while the neurodegenerative disease in which possible defects in mitochondrial Ca(2+) handling have been most intensively investigated is Huntington's Disease. In this brief review evidence that mitochondrial Ca(2+) transport is relevant to neuronal survival in these conditions will be discussed.
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Affiliation(s)
- David G Nicholls
- Buck Institute for Age Research, 8001 Redwood Boulevard, Novato, CA 94945, USA.
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Persiyantseva NA, Bolshakov AP, Mikhailova MM, Birikh KR, Pinelis VG. Retranslocation of active protein kinase C-beta II during calcium overload of cultured neurons. NEUROCHEM J+ 2008. [DOI: 10.1134/s181971240804003x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Bolshakov AP. Glutamate neurotoxicity: Perturbations of ionic homeostasis, mitochondrial dysfunction, and changes in cell functioning. NEUROCHEM J+ 2008. [DOI: 10.1134/s181971240803001x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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