1
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Delgado de la Herran H, Vecellio Reane D, Cheng Y, Katona M, Hosp F, Greotti E, Wettmarshausen J, Patron M, Mohr H, Prudente de Mello N, Chudenkova M, Gorza M, Walia S, Feng MSF, Leimpek A, Mielenz D, Pellegata NS, Langer T, Hajnóczky G, Mann M, Murgia M, Perocchi F. Systematic mapping of mitochondrial calcium uniporter channel (MCUC)-mediated calcium signaling networks. EMBO J 2024:10.1038/s44318-024-00219-w. [PMID: 39261663 DOI: 10.1038/s44318-024-00219-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 08/08/2024] [Accepted: 08/15/2024] [Indexed: 09/13/2024] Open
Abstract
The mitochondrial calcium uniporter channel (MCUC) mediates mitochondrial calcium entry, regulating energy metabolism and cell death. Although several MCUC components have been identified, the molecular basis of mitochondrial calcium signaling networks and their remodeling upon changes in uniporter activity have not been assessed. Here, we map the MCUC interactome under resting conditions and upon chronic loss or gain of mitochondrial calcium uptake. We identify 89 high-confidence interactors that link MCUC to several mitochondrial complexes and pathways, half of which are associated with human disease. As a proof-of-concept, we validate the mitochondrial intermembrane space protein EFHD1 as a binding partner of the MCUC subunits MCU, EMRE, and MCUB. We further show a MICU1-dependent inhibitory effect of EFHD1 on calcium uptake. Next, we systematically survey compensatory mechanisms and functional consequences of mitochondrial calcium dyshomeostasis by analyzing the MCU interactome upon EMRE, MCUB, MICU1, or MICU2 knockdown. While silencing EMRE reduces MCU interconnectivity, MCUB loss-of-function leads to a wider interaction network. Our study provides a comprehensive and high-confidence resource to gain insights into players and mechanisms regulating mitochondrial calcium signaling and their relevance in human diseases.
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Affiliation(s)
- Hilda Delgado de la Herran
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum Munich, Munich, Germany
| | - Denis Vecellio Reane
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum Munich, Munich, Germany
| | - Yiming Cheng
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum Munich, Munich, Germany
| | - Máté Katona
- Department of Pathology, Anatomy, and Cell Biology, MitoCare Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Fabian Hosp
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
- Roche Pharma Research and Early Development, Large Molecule Research, Mass Spectrometry, Penzberg, Germany
| | - Elisa Greotti
- Neuroscience Institute, National Research Council of Italy, Padua, Italy
- Department of Biomedical Sciences, University of Padova, Padua, Italy
- Padova Neuroscience Center, University of Padova, Padua, Italy
| | - Jennifer Wettmarshausen
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum Munich, Munich, Germany
| | - Maria Patron
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, Center for Molecular Medicine, University of Cologne, Cologne, Germany
- Max Planck Institute for Biology of Aging, Cologne, Germany
| | - Hermine Mohr
- Institute of Diabetes and Cancer, Helmholtz Center Munich, Munich, Germany
| | - Natalia Prudente de Mello
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum Munich, Munich, Germany
| | - Margarita Chudenkova
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum Munich, Munich, Germany
| | - Matteo Gorza
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum Munich, Munich, Germany
| | - Safal Walia
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum Munich, Munich, Germany
| | - Michael Sheng-Fu Feng
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum Munich, Munich, Germany
| | - Anja Leimpek
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum Munich, Munich, Germany
| | - Dirk Mielenz
- Division of Molecular Immunology, University of Erlangen, Nikolaus-Fiebiger-Zentrum, FAU Erlangen-Nürnberg, Erlangen, Germany
| | - Natalia S Pellegata
- Institute of Diabetes and Cancer, Helmholtz Center Munich, Munich, Germany
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Thomas Langer
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, Center for Molecular Medicine, University of Cologne, Cologne, Germany
- Max Planck Institute for Biology of Aging, Cologne, Germany
| | - György Hajnóczky
- Department of Pathology, Anatomy, and Cell Biology, MitoCare Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
- Faculty of Health Sciences, Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Marta Murgia
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany.
- Department of Biomedical Sciences, University of Padova, Padua, Italy.
| | - Fabiana Perocchi
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum Munich, Munich, Germany.
- Institute of Neuronal Cell Biology, Technical University of Munich, Munich, Germany.
- Munich Cluster for Systems Neurology, Munich, Germany.
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2
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Balderas E, Lee SHJ, Rai NK, Mollinedo DM, Duron HE, Chaudhuri D. Mitochondrial Calcium Regulation of Cardiac Metabolism in Health and Disease. Physiology (Bethesda) 2024; 39:0. [PMID: 38713090 DOI: 10.1152/physiol.00014.2024] [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: 02/29/2024] [Revised: 05/02/2024] [Accepted: 05/02/2024] [Indexed: 05/08/2024] Open
Abstract
Oxidative phosphorylation is regulated by mitochondrial calcium (Ca2+) in health and disease. In physiological states, Ca2+ enters via the mitochondrial Ca2+ uniporter and rapidly enhances NADH and ATP production. However, maintaining Ca2+ homeostasis is critical: insufficient Ca2+ impairs stress adaptation, and Ca2+ overload can trigger cell death. In this review, we delve into recent insights further defining the relationship between mitochondrial Ca2+ dynamics and oxidative phosphorylation. Our focus is on how such regulation affects cardiac function in health and disease, including heart failure, ischemia-reperfusion, arrhythmias, catecholaminergic polymorphic ventricular tachycardia, mitochondrial cardiomyopathies, Barth syndrome, and Friedreich's ataxia. Several themes emerge from recent data. First, mitochondrial Ca2+ regulation is critical for fuel substrate selection, metabolite import, and matching of ATP supply to demand. Second, mitochondrial Ca2+ regulates both the production and response to reactive oxygen species (ROS), and the balance between its pro- and antioxidant effects is key to how it contributes to physiological and pathological states. Third, Ca2+ exerts localized effects on the electron transport chain (ETC), not through traditional allosteric mechanisms but rather indirectly. These effects hinge on specific transporters, such as the uniporter or the Na+/Ca2+ exchanger, and may not be noticeable acutely, contributing differently to phenotypes depending on whether Ca2+ transporters are acutely or chronically modified. Perturbations in these novel relationships during disease states may either serve as compensatory mechanisms or exacerbate impairments in oxidative phosphorylation. Consequently, targeting mitochondrial Ca2+ holds promise as a therapeutic strategy for a variety of cardiac diseases characterized by contractile failure or arrhythmias.
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Affiliation(s)
- Enrique Balderas
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Sandra H J Lee
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Neeraj K Rai
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - David M Mollinedo
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Hannah E Duron
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Dipayan Chaudhuri
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
- Division of Cardiovascular Medicine, Department of Internal Medicine, Biochemistry, Biomedical Engineering, University of Utah, Salt Lake City, Utah, United States
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3
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Stevens TL, Cohen HM, Garbincius JF, Elrod JW. Mitochondrial calcium uniporter channel gatekeeping in cardiovascular disease. NATURE CARDIOVASCULAR RESEARCH 2024; 3:500-514. [PMID: 39185387 PMCID: PMC11343476 DOI: 10.1038/s44161-024-00463-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 03/18/2024] [Indexed: 08/27/2024]
Abstract
The mitochondrial calcium (mCa2+) uniporter channel (mtCU) resides at the inner mitochondrial membrane and is required for Ca2+ to enter the mitochondrial matrix. The mtCU is essential for cellular function, as mCa2+ regulates metabolism, bioenergetics, signaling pathways and cell death. mCa2+ uptake is primarily regulated by the MICU family (MICU1, MICU2, MICU3), EF-hand-containing Ca2+-sensing proteins, which respond to cytosolic Ca2+ concentrations to modulate mtCU activity. Considering that mitochondrial function and Ca2+ signaling are ubiquitously disrupted in cardiovascular disease, mtCU function has been a hot area of investigation for the last decade. Here we provide an in-depth review of MICU-mediated regulation of mtCU structure and function, as well as potential mtCU-independent functions of these proteins. We detail their role in cardiac physiology and cardiovascular disease by highlighting the phenotypes of different mutant animal models, with an emphasis on therapeutic potential and targets of interest in this pathway.
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Affiliation(s)
- Tyler L. Stevens
- Aging + Cardiovascular Discovery Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Henry M. Cohen
- Aging + Cardiovascular Discovery Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - Joanne F. Garbincius
- Aging + Cardiovascular Discovery Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
| | - John W. Elrod
- Aging + Cardiovascular Discovery Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
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4
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Bround MJ, Abay E, Huo J, Havens JR, York AJ, Bers DM, Molkentin JD. MCU-independent Ca 2+ uptake mediates mitochondrial Ca 2+ overload and necrotic cell death in a mouse model of Duchenne muscular dystrophy. Sci Rep 2024; 14:6751. [PMID: 38514795 PMCID: PMC10957967 DOI: 10.1038/s41598-024-57340-3] [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: 01/19/2024] [Accepted: 03/18/2024] [Indexed: 03/23/2024] Open
Abstract
Mitochondrial Ca2+ overload can mediate mitochondria-dependent cell death, a major contributor to several human diseases. Indeed, Duchenne muscular dystrophy (MD) is driven by dysfunctional Ca2+ influx across the sarcolemma that causes mitochondrial Ca2+ overload, organelle rupture, and muscle necrosis. The mitochondrial Ca2+ uniporter (MCU) complex is the primary characterized mechanism for acute mitochondrial Ca2+ uptake. One strategy for preventing mitochondrial Ca2+ overload is deletion of the Mcu gene, the pore forming subunit of the MCU-complex. Conversely, enhanced MCU-complex Ca2+ uptake is achieved by deleting the inhibitory Mcub gene. Here we show that myofiber-specific Mcu deletion was not protective in a mouse model of Duchenne MD. Specifically, Mcu gene deletion did not reduce muscle histopathology, did not improve muscle function, and did not prevent mitochondrial Ca2+ overload. Moreover, myofiber specific Mcub gene deletion did not augment Duchenne MD muscle pathology. Interestingly, we observed MCU-independent Ca2+ uptake in dystrophic mitochondria that was sufficient to drive mitochondrial permeability transition pore (MPTP) activation and skeletal muscle necrosis, and this same type of activity was observed in heart, liver, and brain mitochondria. These results demonstrate that mitochondria possess an uncharacterized MCU-independent Ca2+ uptake mechanism that is sufficient to drive MPTP-dependent necrosis in MD in vivo.
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Affiliation(s)
- Michael J Bround
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, 240 Albert Sabin Way, MLC 7020, Cincinnati, OH, 45229-3039, USA
| | - Eaman Abay
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, 240 Albert Sabin Way, MLC 7020, Cincinnati, OH, 45229-3039, USA
| | - Jiuzhou Huo
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, 240 Albert Sabin Way, MLC 7020, Cincinnati, OH, 45229-3039, USA
| | - Julian R Havens
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, 240 Albert Sabin Way, MLC 7020, Cincinnati, OH, 45229-3039, USA
| | - Allen J York
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, 240 Albert Sabin Way, MLC 7020, Cincinnati, OH, 45229-3039, USA
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, CA, 95616, USA
| | - Jeffery D Molkentin
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, 240 Albert Sabin Way, MLC 7020, Cincinnati, OH, 45229-3039, USA.
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5
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Lin HP, Petersen JD, Gilsrud AJ, Madruga A, D’Silva TM, Huang X, Shammas MK, Randolph NP, Li Y, Jones DR, Pacold ME, Narendra DP. DELE1 promotes translation-associated homeostasis, growth, and survival in mitochondrial myopathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.29.582673. [PMID: 38529505 PMCID: PMC10962736 DOI: 10.1101/2024.02.29.582673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
Mitochondrial dysfunction causes devastating disorders, including mitochondrial myopathy. Here, we identified that diverse mitochondrial myopathy models elicit a protective mitochondrial integrated stress response (mt-ISR), mediated by OMA1-DELE1 signaling. The response was similar following disruptions in mtDNA maintenance, from knockout of Tfam, and mitochondrial protein unfolding, from disease-causing mutations in CHCHD10 (G58R and S59L). The preponderance of the response was directed at upregulating pathways for aminoacyl-tRNA biosynthesis, the intermediates for protein synthesis, and was similar in heart and skeletal muscle but more limited in brown adipose challenged with cold stress. Strikingly, models with early DELE1 mt-ISR activation failed to grow and survive to adulthood in the absence of Dele1, accounting for some but not all of OMA1's protection. Notably, the DELE1 mt-ISR did not slow net protein synthesis in stressed striated muscle, but instead prevented loss of translation-associated proteostasis in muscle fibers. Together our findings identify that the DELE1 mt-ISR mediates a stereotyped response to diverse forms of mitochondrial stress and is particularly critical for maintaining growth and survival in early-onset mitochondrial myopathy.
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Affiliation(s)
- Hsin-Pin Lin
- Inherited Movement Disorders Unit, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jennifer D. Petersen
- Inherited Movement Disorders Unit, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alexandra J. Gilsrud
- Inherited Movement Disorders Unit, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Angelo Madruga
- Inherited Movement Disorders Unit, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Theresa M. D’Silva
- Inherited Movement Disorders Unit, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xiaoping Huang
- Inherited Movement Disorders Unit, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mario K. Shammas
- Inherited Movement Disorders Unit, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nicholas P. Randolph
- Inherited Movement Disorders Unit, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yan Li
- Proteomics Core Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Drew R. Jones
- Department of Radiation Oncology, NYU Langone Health, New York, United States
| | - Michael E. Pacold
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, United States
- Perlmutter Cancer Center, NYU Langone Health, New York, United States
| | - Derek P. Narendra
- Inherited Movement Disorders Unit, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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6
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Corne A, Adolphe F, Estaquier J, Gaumer S, Corsi JM. ATF4 Signaling in HIV-1 Infection: Viral Subversion of a Stress Response Transcription Factor. BIOLOGY 2024; 13:146. [PMID: 38534416 DOI: 10.3390/biology13030146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 02/13/2024] [Accepted: 02/20/2024] [Indexed: 03/28/2024]
Abstract
Cellular integrated stress response (ISR), the mitochondrial unfolded protein response (UPRmt), and IFN signaling are associated with viral infections. Activating transcription factor 4 (ATF4) plays a pivotal role in these pathways and controls the expression of many genes involved in redox processes, amino acid metabolism, protein misfolding, autophagy, and apoptosis. The precise role of ATF4 during viral infection is unclear and depends on cell hosts, viral agents, and models. Furthermore, ATF4 signaling can be hijacked by pathogens to favor viral infection and replication. In this review, we summarize the ATF4-mediated signaling pathways in response to viral infections, focusing on human immunodeficiency virus 1 (HIV-1). We examine the consequences of ATF4 activation for HIV-1 replication and reactivation. The role of ATF4 in autophagy and apoptosis is explored as in the context of HIV-1 infection programmed cell deaths contribute to the depletion of CD4 T cells. Furthermore, ATF4 can also participate in the establishment of innate and adaptive immunity that is essential for the host to control viral infections. We finally discuss the putative role of the ATF4 paralogue, named ATF5, in HIV-1 infection. This review underlines the role of ATF4 at the crossroads of multiple processes reflecting host-pathogen interactions.
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Affiliation(s)
- Adrien Corne
- Laboratoire de Génétique et Biologie Cellulaire, Université Versailles-Saint-Quentin-en-Yvelines, Université Paris-Saclay, 78000 Versailles, France
- CHU de Québec Research Center, Laval University, Quebec City, QC G1V 4G2, Canada
| | - Florine Adolphe
- Laboratoire de Génétique et Biologie Cellulaire, Université Versailles-Saint-Quentin-en-Yvelines, Université Paris-Saclay, 78000 Versailles, France
| | - Jérôme Estaquier
- CHU de Québec Research Center, Laval University, Quebec City, QC G1V 4G2, Canada
- INSERM U1124, Université Paris Cité, 75006 Paris, France
| | - Sébastien Gaumer
- Laboratoire de Génétique et Biologie Cellulaire, Université Versailles-Saint-Quentin-en-Yvelines, Université Paris-Saclay, 78000 Versailles, France
| | - Jean-Marc Corsi
- Laboratoire de Génétique et Biologie Cellulaire, Université Versailles-Saint-Quentin-en-Yvelines, Université Paris-Saclay, 78000 Versailles, France
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7
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Pain P, Spinelli F, Gherardi G. Mitochondrial Cation Signalling in the Control of Inflammatory Processes. Int J Mol Sci 2023; 24:16724. [PMID: 38069047 PMCID: PMC10706693 DOI: 10.3390/ijms242316724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/17/2023] [Accepted: 11/17/2023] [Indexed: 12/18/2023] Open
Abstract
Mitochondria are the bioenergetic organelles responsible for the maintenance of cellular homeostasis and have also been found to be associated with inflammation. They are necessary to induce and maintain innate and adaptive immune cell responses, acting as signalling platforms and mediators in effector responses. These organelles are also known to play a pivotal role in cation homeostasis as well, which regulates the inflammatory responses through the modulation of these cation channels. In particular, this review focuses on mitochondrial Ca2+ and K+ fluxes in the regulation of inflammatory response. Nevertheless, this review aims to understand the interplay of these inflammation inducers and pathophysiological conditions. In detail, we discuss some examples of chronic inflammation such as lung, bowel, and metabolic inflammatory diseases caused by a persistent activation of the innate immune response due to a dysregulation of mitochondrial cation homeostasis.
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Affiliation(s)
| | | | - Gaia Gherardi
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy; (P.P.); (F.S.)
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8
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Montoro-Gámez C, Nolte H, Molinié T, Evangelista G, Tröder SE, Barth E, Popovic M, Trifunovic A, Zevnik B, Langer T, Rugarli EI. SARM1 deletion delays cerebellar but not spinal cord degeneration in an enhanced mouse model of SPG7 deficiency. Brain 2023; 146:4117-4131. [PMID: 37086482 DOI: 10.1093/brain/awad136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 03/16/2023] [Accepted: 04/10/2023] [Indexed: 04/24/2023] Open
Abstract
Hereditary spastic paraplegia is a neurological condition characterized by predominant axonal degeneration in long spinal tracts, leading to weakness and spasticity in the lower limbs. The nicotinamide adenine dinucleotide (NAD+)-consuming enzyme SARM1 has emerged as a key executioner of axonal degeneration upon nerve transection and in some neuropathies. An increase in the nicotinamide mononucleotide/NAD+ ratio activates SARM1, causing catastrophic NAD+ depletion and axonal degeneration. However, the role of SARM1 in the pathogenesis of hereditary spastic paraplegia has not been investigated. Here, we report an enhanced mouse model for hereditary spastic paraplegia caused by mutations in SPG7. The eSpg7 knockout mouse carries a deletion in both Spg7 and Afg3l1, a redundant homologue expressed in mice but not in humans. The eSpg7 knockout mice recapitulate the phenotypic features of human patients, showing progressive symptoms of spastic-ataxia and degeneration of axons in the spinal cord as well as the cerebellum. We show that the lack of SPG7 rewires the mitochondrial proteome in both tissues, leading to an early onset decrease in mito-ribosomal subunits and a remodelling of mitochondrial solute carriers and transporters. To interrogate mechanisms leading to axonal degeneration in this mouse model, we explored the involvement of SARM1. Deletion of SARM1 delays the appearance of ataxic signs, rescues mitochondrial swelling and axonal degeneration of cerebellar granule cells and dampens neuroinflammation in the cerebellum. The loss of SARM1 also prevents endoplasmic reticulum abnormalities in long spinal cord axons, but does not halt the degeneration of these axons. Our data thus reveal a neuron-specific interplay between SARM1 and mitochondrial dysfunction caused by lack of SPG7 in hereditary spastic paraplegia.
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Affiliation(s)
- Carolina Montoro-Gámez
- Institute for Genetics, University of Cologne, Cologne 50931, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne 50931, Germany
| | - Hendrik Nolte
- Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
| | - Thibaut Molinié
- Institute for Genetics, University of Cologne, Cologne 50931, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne 50931, Germany
| | - Giovanna Evangelista
- Institute for Genetics, University of Cologne, Cologne 50931, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne 50931, Germany
| | - Simon E Tröder
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne 50931, Germany
- in vivo Research Facility, Medical Faculty and University Hospital Cologne, University of Cologne, Cologne 50931, Germany
| | - Esther Barth
- Institute for Genetics, University of Cologne, Cologne 50931, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne 50931, Germany
| | - Milica Popovic
- Institute for Genetics, University of Cologne, Cologne 50931, Germany
- Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, Cologne 50931, Germany
| | - Aleksandra Trifunovic
- Institute for Genetics, University of Cologne, Cologne 50931, Germany
- Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, Cologne 50931, Germany
- Center for Molecular Medicine (CMMC), University of Cologne, Cologne 50931, Germany
| | - Branko Zevnik
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne 50931, Germany
- in vivo Research Facility, Medical Faculty and University Hospital Cologne, University of Cologne, Cologne 50931, Germany
| | - Thomas Langer
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne 50931, Germany
- Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
| | - Elena I Rugarli
- Institute for Genetics, University of Cologne, Cologne 50931, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne 50931, Germany
- Center for Molecular Medicine (CMMC), University of Cologne, Cologne 50931, Germany
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9
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Lee SH, Duron HE, Chaudhuri D. Beyond the TCA cycle: new insights into mitochondrial calcium regulation of oxidative phosphorylation. Biochem Soc Trans 2023; 51:1661-1673. [PMID: 37641565 PMCID: PMC10508640 DOI: 10.1042/bst20230012] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/10/2023] [Accepted: 08/16/2023] [Indexed: 08/31/2023]
Abstract
While mitochondria oxidative phosphorylation is broadly regulated, the impact of mitochondrial Ca2+ on substrate flux under both physiological and pathological conditions is increasingly being recognized. Under physiologic conditions, mitochondrial Ca2+ enters through the mitochondrial Ca2+ uniporter and boosts ATP production. However, maintaining Ca2+ homeostasis is crucial as too little Ca2+ inhibits adaptation to stress and Ca2+ overload can trigger cell death. In this review, we discuss new insights obtained over the past several years expanding the relationship between mitochondrial Ca2+ and oxidative phosphorylation, with most data obtained from heart, liver, or skeletal muscle. Two new themes are emerging. First, beyond boosting ATP synthesis, Ca2+ appears to be a critical determinant of fuel substrate choice between glucose and fatty acids. Second, Ca2+ exerts local effects on the electron transport chain indirectly, not via traditional allosteric mechanisms. These depend critically on the transporters involved, such as the uniporter or the Na+-Ca2+ exchanger. Alteration of these new relationships during disease can be either compensatory or harmful and suggest that targeting mitochondrial Ca2+ may be of therapeutic benefit during diseases featuring impairments in oxidative phosphorylation.
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Affiliation(s)
- Sandra H. Lee
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, USA
| | - Hannah E. Duron
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, USA
| | - Dipayan Chaudhuri
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, USA
- Division of Cardiovascular Medicine, Department of Internal Medicine, Biochemistry, Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
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10
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Kadam A, Jadiya P, Tomar D. Post-translational modifications and protein quality control of mitochondrial channels and transporters. Front Cell Dev Biol 2023; 11:1196466. [PMID: 37601094 PMCID: PMC10434574 DOI: 10.3389/fcell.2023.1196466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 07/24/2023] [Indexed: 08/22/2023] Open
Abstract
Mitochondria play a critical role in energy metabolism and signal transduction, which is tightly regulated by proteins, metabolites, and ion fluxes. Metabolites and ion homeostasis are mainly mediated by channels and transporters present on mitochondrial membranes. Mitochondria comprise two distinct compartments, the outer mitochondrial membrane (OMM) and the inner mitochondrial membrane (IMM), which have differing permeabilities to ions and metabolites. The OMM is semipermeable due to the presence of non-selective molecular pores, while the IMM is highly selective and impermeable due to the presence of specialized channels and transporters which regulate ion and metabolite fluxes. These channels and transporters are modulated by various post-translational modifications (PTMs), including phosphorylation, oxidative modifications, ions, and metabolites binding, glycosylation, acetylation, and others. Additionally, the mitochondrial protein quality control (MPQC) system plays a crucial role in ensuring efficient molecular flux through the mitochondrial membranes by selectively removing mistargeted or defective proteins. Inefficient functioning of the transporters and channels in mitochondria can disrupt cellular homeostasis, leading to the onset of various pathological conditions. In this review, we provide a comprehensive overview of the current understanding of mitochondrial channels and transporters in terms of their functions, PTMs, and quality control mechanisms.
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Affiliation(s)
- Ashlesha Kadam
- Department of Internal Medicine, Section of Cardiovascular Medicine, Section of Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Pooja Jadiya
- Department of Internal Medicine, Section of Gerontology and Geriatric Medicine, Section of Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Dhanendra Tomar
- Department of Internal Medicine, Section of Cardiovascular Medicine, Section of Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
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11
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Petersen CE, Sun J, Silva K, Kosmach A, Balaban RS, Murphy E. Increased mitochondrial free Ca 2+ during ischemia is suppressed, but not eliminated by, germline deletion of the mitochondrial Ca 2+ uniporter. Cell Rep 2023; 42:112735. [PMID: 37421627 PMCID: PMC10529381 DOI: 10.1016/j.celrep.2023.112735] [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: 10/07/2022] [Revised: 04/20/2023] [Accepted: 06/18/2023] [Indexed: 07/10/2023] Open
Abstract
Mitochondrial Ca2+ overload is proposed to regulate cell death via opening of the mitochondrial permeability transition pore. It is hypothesized that inhibition of the mitochondrial Ca2+ uniporter (MCU) will prevent Ca2+ accumulation during ischemia/reperfusion and thereby reduce cell death. To address this, we evaluate mitochondrial Ca2+ in ex-vivo-perfused hearts from germline MCU-knockout (KO) and wild-type (WT) mice using transmural spectroscopy. Matrix Ca2+ levels are measured with a genetically encoded, red fluorescent Ca2+ indicator (R-GECO1) using an adeno-associated viral vector (AAV9) for delivery. Due to the pH sensitivity of R-GECO1 and the known fall in pH during ischemia, hearts are glycogen depleted to decrease the ischemic fall in pH. At 20 min of ischemia, there is significantly less mitochondrial Ca2+ in MCU-KO hearts compared with MCU-WT controls. However, an increase in mitochondrial Ca2+ is present in MCU-KO hearts, suggesting that mitochondrial Ca2+ overload during ischemia is not solely dependent on MCU.
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Affiliation(s)
- Courtney E Petersen
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Junhui Sun
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kavisha Silva
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anna Kosmach
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Robert S Balaban
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Elizabeth Murphy
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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12
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Novorolsky RJ, Kasheke GDS, Hakim A, Foldvari M, Dorighello GG, Sekler I, Vuligonda V, Sanders ME, Renden RB, Wilson JJ, Robertson GS. Preserving and enhancing mitochondrial function after stroke to protect and repair the neurovascular unit: novel opportunities for nanoparticle-based drug delivery. Front Cell Neurosci 2023; 17:1226630. [PMID: 37484823 PMCID: PMC10360135 DOI: 10.3389/fncel.2023.1226630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 06/22/2023] [Indexed: 07/25/2023] Open
Abstract
The neurovascular unit (NVU) is composed of vascular cells, glia, and neurons that form the basic component of the blood brain barrier. This intricate structure rapidly adjusts cerebral blood flow to match the metabolic needs of brain activity. However, the NVU is exquisitely sensitive to damage and displays limited repair after a stroke. To effectively treat stroke, it is therefore considered crucial to both protect and repair the NVU. Mitochondrial calcium (Ca2+) uptake supports NVU function by buffering Ca2+ and stimulating energy production. However, excessive mitochondrial Ca2+ uptake causes toxic mitochondrial Ca2+ overloading that triggers numerous cell death pathways which destroy the NVU. Mitochondrial damage is one of the earliest pathological events in stroke. Drugs that preserve mitochondrial integrity and function should therefore confer profound NVU protection by blocking the initiation of numerous injury events. We have shown that mitochondrial Ca2+ uptake and efflux in the brain are mediated by the mitochondrial Ca2+ uniporter complex (MCUcx) and sodium/Ca2+/lithium exchanger (NCLX), respectively. Moreover, our recent pharmacological studies have demonstrated that MCUcx inhibition and NCLX activation suppress ischemic and excitotoxic neuronal cell death by blocking mitochondrial Ca2+ overloading. These findings suggest that combining MCUcx inhibition with NCLX activation should markedly protect the NVU. In terms of promoting NVU repair, nuclear hormone receptor activation is a promising approach. Retinoid X receptor (RXR) and thyroid hormone receptor (TR) agonists activate complementary transcriptional programs that stimulate mitochondrial biogenesis, suppress inflammation, and enhance the production of new vascular cells, glia, and neurons. RXR and TR agonism should thus further improve the clinical benefits of MCUcx inhibition and NCLX activation by increasing NVU repair. However, drugs that either inhibit the MCUcx, or stimulate the NCLX, or activate the RXR or TR, suffer from adverse effects caused by undesired actions on healthy tissues. To overcome this problem, we describe the use of nanoparticle drug formulations that preferentially target metabolically compromised and damaged NVUs after an ischemic or hemorrhagic stroke. These nanoparticle-based approaches have the potential to improve clinical safety and efficacy by maximizing drug delivery to diseased NVUs and minimizing drug exposure in healthy brain and peripheral tissues.
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Affiliation(s)
- Robyn J. Novorolsky
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Gracious D. S. Kasheke
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Antoine Hakim
- School of Pharmacy, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| | - Marianna Foldvari
- School of Pharmacy, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| | - Gabriel G. Dorighello
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben Gurion University, Beersheva, Israel
| | | | | | - Robert B. Renden
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, United States
| | - Justin J. Wilson
- Department of Chemistry and Chemical Biology, College of Arts and Sciences, Cornell University, Ithaca, NY, United States
| | - George S. Robertson
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Department of Psychiatry, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
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13
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De Mario A, D'Angelo D, Zanotti G, Raffaello A, Mammucari C. The mitochondrial calcium uniporter complex–A play in five acts. Cell Calcium 2023; 112:102720. [PMID: 37001308 DOI: 10.1016/j.ceca.2023.102720] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/22/2023] [Accepted: 03/23/2023] [Indexed: 03/30/2023]
Abstract
Mitochondrial Ca2+ (mitCa2+) uptake controls both intraorganellar and cytosolic functions. Within the organelle, [Ca2+] increases regulate the activity of tricarboxylic acid (TCA) cycle enzymes, thus sustaining oxidative metabolism and ATP production. Reactive oxygen species (ROS) are also generated as side products of oxygen consumption. At the same time, mitochondria act as buffers of cytosolic Ca2+ (cytCa2+) increases, thus regulating Ca2+-dependent cellular processes. In pathological conditions, mitCa2+ overload triggers the opening of the mitochondrial permeability transition pore (mPTP) and the release of apoptotic cofactors. MitCa2+ uptake occurs in response of local [Ca2+] increases in sites of proximity between the endoplasmic reticulum (ER) and the mitochondria and is mediated by the mitochondrial Ca2+ uniporter (MCU), a highly selective channel of the inner mitochondrial membrane (IMM). Both channel and regulatory subunits form the MCU complex (MCUC). Cryogenic electron microscopy (Cryo-EM) and crystal structures revealed the correct assembly of MCUC and the function of critical residues for the regulation of Ca2+ conductance.
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14
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Gerasimenko JV, Gerasimenko OV. The role of Ca 2+ signalling in the pathology of exocrine pancreas. Cell Calcium 2023; 112:102740. [PMID: 37058923 PMCID: PMC10840512 DOI: 10.1016/j.ceca.2023.102740] [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: 02/28/2023] [Revised: 04/04/2023] [Accepted: 04/06/2023] [Indexed: 04/16/2023]
Abstract
Exocrine pancreas has been the field of many successful studies in pancreatic physiology and pathology. However, related disease - acute pancreatitis (AP) is still takes it toll with more than 100,000 related deaths worldwide per year. In spite of significant scientific progress and several human trials currently running for AP, there is still no specific treatment in the clinic. Studies of the mechanism of initiation of AP have identified two crucial conditions: sustained elevations of cytoplasmic calcium concentration (Ca2+ plateau) and significantly reduced intracellular energy (ATP depletion). These hallmarks are interdependent, i.e., Ca2+ plateau increase energy demand for its clearance while energy production is greatly affected by the pathology. Result of long standing Ca2+ plateau is destabilisation of the secretory granules and premature activation of the digestive enzymes leading to necrotic cell death. Main attempts so far to break the vicious circle of cell death have been concentrated on reduction of Ca2+ overload or reduction of ATP depletion. This review will summarise these approaches, including recent developments of potential therapies for AP.
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Affiliation(s)
- Julia V Gerasimenko
- Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff, Wales, CF10 3AX, United Kingdom.
| | - Oleg V Gerasimenko
- Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff, Wales, CF10 3AX, United Kingdom
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15
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Jeyarajan S, Zhang IX, Arvan P, Lentz SI, Satin LS. Simultaneous Measurement of Changes in Mitochondrial and Endoplasmic Reticulum Free Calcium in Pancreatic Beta Cells. BIOSENSORS 2023; 13:382. [PMID: 36979594 PMCID: PMC10046164 DOI: 10.3390/bios13030382] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/28/2023] [Accepted: 03/08/2023] [Indexed: 05/28/2023]
Abstract
The free calcium (Ca2+) levels in pancreatic beta cell organelles have been the subject of many recent investigations. Under pathophysiological conditions, disturbances in these pools have been linked to altered intracellular communication and cellular dysfunction. To facilitate studies of subcellular Ca2+ signaling in beta cells and, particularly, signaling between the endoplasmic reticulum (ER) and mitochondria, we designed a novel dual Ca2+ sensor which we termed DS-1. DS-1 encodes two stoichiometrically fluorescent proteins within a single plasmid, G-CEPIA-er, targeted to the ER and R-CEPIA3-mt, targeted to mitochondria. Our goal was to simultaneously measure the ER and mitochondrial Ca2+ in cells in real time. The Kds of G-CEPIA-er and R-CEPIA3-mt for Ca2+ are 672 and 3.7 μM, respectively. Confocal imaging of insulin-secreting INS-1 832/13 expressing DS-1 confirmed that the green and red fluorophores correctly colocalized with organelle-specific fluorescent markers as predicted. Further, we tested whether DS-1 exhibited the functional properties expected by challenging an INS-1 cell to glucose concentrations or drugs having well-documented effects on the ER and mitochondrial Ca2+ handling. The data obtained were consistent with those seen using other single organelle targeted probes. These results taken together suggest that DS-1 is a promising new approach for investigating Ca2+ signaling within multiple organelles of the cell.
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Affiliation(s)
- Sivakumar Jeyarajan
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48105, USA; (S.J.)
| | - Irina X Zhang
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48105, USA; (S.J.)
| | - Peter Arvan
- Department of Internal Medicine, Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Stephen I. Lentz
- Department of Internal Medicine, Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Leslie S. Satin
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48105, USA; (S.J.)
- Department of Internal Medicine, Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
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16
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Austin S, Mekis R, Mohammed SEM, Scalise M, Wang W, Galluccio M, Pfeiffer C, Borovec T, Parapatics K, Vitko D, Dinhopl N, Demaurex N, Bennett KL, Indiveri C, Nowikovsky K. TMBIM5 is the Ca 2+ /H + antiporter of mammalian mitochondria. EMBO Rep 2022; 23:e54978. [PMID: 36321428 PMCID: PMC9724676 DOI: 10.15252/embr.202254978] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 09/07/2022] [Accepted: 10/07/2022] [Indexed: 11/25/2022] Open
Abstract
Mitochondrial Ca2+ ions are crucial regulators of bioenergetics and cell death pathways. Mitochondrial Ca2+ content and cytosolic Ca2+ homeostasis strictly depend on Ca2+ transporters. In recent decades, the major players responsible for mitochondrial Ca2+ uptake and release have been identified, except the mitochondrial Ca2+ /H+ exchanger (CHE). Originally identified as the mitochondrial K+ /H+ exchanger, LETM1 was also considered as a candidate for the mitochondrial CHE. Defining the mitochondrial interactome of LETM1, we identify TMBIM5/MICS1, the only mitochondrial member of the TMBIM family, and validate the physical interaction of TMBIM5 and LETM1. Cell-based and cell-free biochemical assays demonstrate the absence or greatly reduced Na+ -independent mitochondrial Ca2+ release in TMBIM5 knockout or pH-sensing site mutants, respectively, and pH-dependent Ca2+ transport by recombinant TMBIM5. Taken together, we demonstrate that TMBIM5, but not LETM1, is the long-sought mitochondrial CHE, involved in setting and regulating the mitochondrial proton gradient. This finding provides the final piece of the puzzle of mitochondrial Ca2+ transporters and opens the door to exploring its importance in health and disease, and to developing drugs modulating Ca2+ exchange.
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Affiliation(s)
- Shane Austin
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
- Present address:
Department of Biological & Chemical SciencesThe University of the West Indies, Cave Hill CampusCave HillBarbados
| | - Ronald Mekis
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and BiophysicsUniversity of Veterinary Medicine ViennaViennaAustria
| | - Sami E M Mohammed
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and BiophysicsUniversity of Veterinary Medicine ViennaViennaAustria
| | - Mariafrancesca Scalise
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular BiotechnologyUniversity of CalabriaArcavacata di RendeItaly
| | - Wen‐An Wang
- Department of Cell Physiology & MetabolismUniversity of GenevaGenevaSwitzerland
| | - Michele Galluccio
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular BiotechnologyUniversity of CalabriaArcavacata di RendeItaly
| | - Christina Pfeiffer
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
| | - Tamara Borovec
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and BiophysicsUniversity of Veterinary Medicine ViennaViennaAustria
| | - Katja Parapatics
- CeMM Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Dijana Vitko
- CeMM Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Nora Dinhopl
- Department of Pathobiology, Institute of PathologyUniversity of Veterinary MedicineViennaAustria
| | - Nicolas Demaurex
- Department of Cell Physiology & MetabolismUniversity of GenevaGenevaSwitzerland
| | - Keiryn L Bennett
- CeMM Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular BiotechnologyUniversity of CalabriaArcavacata di RendeItaly
- CNR Institute of BiomembranesBioenergetics and Molecular Biotechnologies (IBIOM)BariItaly
| | - Karin Nowikovsky
- Department of Internal Medicine I and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and BiophysicsUniversity of Veterinary Medicine ViennaViennaAustria
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17
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Ren M, Schlame M. The mystery of mitochondrial plasticity: TMBIM5 integrates metabolic state and proteostasis. EMBO J 2022; 41:e111834. [PMID: 35912455 PMCID: PMC9379548 DOI: 10.15252/embj.2022111834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 06/15/2022] [Indexed: 11/09/2022] Open
Abstract
How cellular cues alter the mitochondrial proteome and impact the composition of mitochondrial proteins remains poorly understood. In this issue of The EMBO Journal, Patron et al (2022) identify TMBIM5 as an important link between calcium homeostasis, proton motive force, and mitochondrial proteolysis, by which the organelle can modify its protein composition. The results may be crucial for our understanding of the plasticity of mitochondria.
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Affiliation(s)
- Mindong Ren
- Departments of Anesthesiology and Cell BiologyNYU School of MedicineNew YorkNYUSA
| | - Michael Schlame
- Departments of Anesthesiology and Cell BiologyNYU School of MedicineNew YorkNYUSA
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