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Xu P, Swain S, Novorolsky RJ, Garcia E, Huang Z, Snutch TP, Wilson JJ, Robertson GS, Renden RB. The mitochondrial calcium uniporter inhibitor Ru265 increases neuronal excitability and reduces neurotransmission via off-target effects. Br J Pharmacol 2024. [PMID: 38779706 DOI: 10.1111/bph.16425] [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: 09/25/2023] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND AND PURPOSE Excitotoxicity due to mitochondrial calcium (Ca2+) overloading can trigger neuronal cell death in a variety of pathologies. Inhibiting the mitochondrial calcium uniporter (MCU) has been proposed as a therapeutic avenue to prevent calcium overloading. Ru265 (ClRu(NH3)4(μ-N)Ru(NH3)4Cl]Cl3) is a cell-permeable inhibitor of the mitochondrial calcium uniporter (MCU) with nanomolar affinity. Ru265 reduces sensorimotor deficits and neuronal death in models of ischemic stroke. However, the therapeutic use of Ru265 is limited by the induction of seizure-like behaviours. EXPERIMENTAL APPROACH We examined the effect of Ru265 on synaptic and neuronal function in acute brain slices and hippocampal neuron cultures derived from mice, in control and where MCU expression was genetically abrogated. KEY RESULTS Ru265 decreased evoked responses from calyx terminals and induced spontaneous action potential firing of both the terminal and postsynaptic principal cell. Recordings of presynaptic Ca2+ currents suggested that Ru265 blocks the P/Q type channel, confirmed by the inhibition of currents in cells exogenously expressing the P/Q type channel. Measurements of presynaptic K+ currents further revealed that Ru265 blocked a KCNQ current, leading to increased membrane excitability, underlying spontaneous spiking. Ca2+ imaging of hippocampal neurons showed that Ru265 increased synchronized, high-amplitude events, recapitulating seizure-like activity seen in vivo. Importantly, MCU ablation did not suppress Ru265-induced increases in neuronal activity and seizures. CONCLUSIONS AND IMPLICATIONS Our findings provide a mechanistic explanation for the pro-convulsant effects of Ru265 and suggest counter screening assays based on the measurement of P/Q and KCNQ channel currents to identify safe MCU inhibitors.
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Affiliation(s)
- Peng Xu
- Department of Physiology and Cell Biology, University of Nevada, Reno, Reno, Nevada, USA
| | - Sarpras Swain
- Department of Physiology and Cell Biology, University of Nevada, Reno, Reno, Nevada, USA
| | - Robyn J Novorolsky
- Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Esperanza Garcia
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health University of British Columbia, Vancouver, British Columbia, Canada
| | - Zhouyang Huang
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, USA
| | - Terrance P Snutch
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health University of British Columbia, Vancouver, British Columbia, Canada
| | - Justin J Wilson
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, USA
| | - George S Robertson
- Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Robert B Renden
- Department of Physiology and Cell Biology, University of Nevada, Reno, Reno, Nevada, USA
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Bierhansl L, Gola L, Narayanan V, Dik A, Meuth SG, Wiendl H, Kovac S. Neuronal Mitochondrial Calcium Uniporter (MCU) Deficiency Is Neuroprotective in Hyperexcitability by Modulation of Metabolic Pathways and ROS Balance. Mol Neurobiol 2024:10.1007/s12035-024-04148-x. [PMID: 38652352 DOI: 10.1007/s12035-024-04148-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 03/23/2024] [Indexed: 04/25/2024]
Abstract
Epilepsy is one of the most common neurological disorders in the world. Common epileptic drugs generally affect ion channels or neurotransmitters and prevent the emergence of seizures. However, up to a third of the patients suffer from drug-resistant epilepsy, and there is an urgent need to develop new therapeutic strategies that go beyond acute antiepileptic (antiseizure) therapies towards therapeutics that also might have effects on chronic epilepsy comorbidities such as cognitive decline and depression. The mitochondrial calcium uniporter (MCU) mediates rapid mitochondrial Ca2+ transport through the inner mitochondrial membrane. Ca2+ influx is essential for mitochondrial functions, but longer elevations of intracellular Ca2+ levels are closely associated with seizure-induced neuronal damage, which are underlying mechanisms of cognitive decline and depression. Using neuronal-specific MCU knockout mice (MCU-/-ΔN), we demonstrate that neuronal MCU deficiency reduced hippocampal excitability in vivo. Furthermore, in vitro analyses of hippocampal glioneuronal cells reveal no change in total Ca2+ levels but differences in intracellular Ca2+ handling. MCU-/-ΔN reduces ROS production, declines metabolic fluxes, and consequently prevents glioneuronal cell death. This effect was also observed under pathological conditions, such as the low magnesium culture model of seizure-like activity or excitotoxic glutamate stimulation, whereby MCU-/-ΔN reduces ROS levels and suppresses Ca2+ overload seen in WT cells. This study highlights the importance of MCU at the interface of Ca2+ handling and metabolism as a mediator of stress-related mitochondrial dysfunction, which indicates the modulation of MCU as a potential target for future antiepileptogenic therapy.
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Affiliation(s)
- Laura Bierhansl
- Department of Neurology With Institute of Translational Neurology, University Hospital Münster, Münster, Germany
| | - Lukas Gola
- Department of Neurology With Institute of Translational Neurology, University Hospital Münster, Münster, Germany
| | - Venu Narayanan
- Department of Neurology With Institute of Translational Neurology, University Hospital Münster, Münster, Germany
| | - Andre Dik
- Department of Neurology With Institute of Translational Neurology, University Hospital Münster, Münster, Germany
| | - Sven G Meuth
- Department of Neurology, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Heinz Wiendl
- Department of Neurology With Institute of Translational Neurology, University Hospital Münster, Münster, Germany
| | - Stjepana Kovac
- Department of Neurology With Institute of Translational Neurology, University Hospital Münster, Münster, Germany.
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3
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Pannoni KE, Fischer QS, Tarannum R, Cawley ML, Alsalman MM, Acosta N, Ezigbo C, Gil DV, Campbell LA, Farris S. MCU-enriched dendritic mitochondria regulate plasticity in distinct hippocampal circuits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.10.566606. [PMID: 37986798 PMCID: PMC10659405 DOI: 10.1101/2023.11.10.566606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Mitochondria are dynamic organelles that are morphologically and functionally diverse across cell types and subcellular compartments in order to meet unique energy demands. Mitochondrial dysfunction has been implicated in a wide variety of neurological disorders, including psychiatric disorders like schizophrenia and bipolar disorder. Despite it being well known that mitochondria are essential for synaptic transmission and synaptic plasticity, the mechanisms regulating mitochondria in support of normal synapse function are incompletely understood. The mitochondrial calcium uniporter (MCU) regulates calcium entry into the mitochondria, which in turn regulates the bioenergetics and distribution of mitochondria to active synapses. Evidence suggests that calcium influx via MCU couples neuronal activity to mitochondrial metabolism and ATP production, which would allow neurons to rapidly adapt to changing energy demands. Intriguingly, MCU is uniquely enriched in hippocampal CA2 distal dendrites relative to neighboring hippocampal CA1 or CA3 distal dendrites, however, the functional significance of this enrichment is not clear. Synapses from the entorhinal cortex layer II (ECII) onto CA2 distal dendrites readily express long term potentiation (LTP), unlike the LTP-resistant synapses from CA3 onto CA2 proximal dendrites, but the mechanisms underlying these different plasticity profiles are unknown. We hypothesized that enrichment of MCU near ECII-CA2 synapses promotes LTP in an otherwise plasticity-restricted cell type. Using a CA2-specific MCU knockout (cKO) mouse, we found that MCU is required for LTP at distal dendrite synapses but does not affect the lack of LTP at proximal dendrite synapses. Loss of LTP at ECII-CA2 synapses correlated with a trend for decreased spine density in CA2 distal dendrites of cKO mice compared to control (CTL) mice, which was predominantly seen in immature spines. Moreover, mitochondria were significantly smaller and more numerous across all dendritic layers of CA2 in cKO mice compared to CTL mice, suggesting an overall increase in mitochondrial fragmentation. Fragmented mitochondria might have functional changes, such as altered ATP production, that might explain a deficit in synaptic plasticity. Collectively, our data reveal that MCU regulates layer-specific forms of plasticity in CA2 dendrites, potentially by maintaining proper mitochondria morphology and distribution within dendrites. Differences in MCU expression across different cell types and circuits might be a general mechanism to tune the sensitivity of mitochondria to cytoplasmic calcium levels to power synaptic plasticity.
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Affiliation(s)
- Katy E. Pannoni
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Quentin S. Fischer
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Renesa Tarannum
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia
| | - Mikel L. Cawley
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia
| | - Mayd M. Alsalman
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Nicole Acosta
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Chisom Ezigbo
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Daniela V. Gil
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Logan A. Campbell
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Shannon Farris
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Department of Biomedical Sciences & Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia
- Virginia Tech Carilion School of Medicine, Roanoke, Virginia
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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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Doser RL, Knight KM, Deihl EW, Hoerndli FJ. Activity-dependent mitochondrial ROS signaling regulates recruitment of glutamate receptors to synapses. eLife 2024; 13:e92376. [PMID: 38483244 PMCID: PMC10990490 DOI: 10.7554/elife.92376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 03/13/2024] [Indexed: 04/04/2024] Open
Abstract
Our understanding of mitochondrial signaling in the nervous system has been limited by the technical challenge of analyzing mitochondrial function in vivo. In the transparent genetic model Caenorhabditis elegans, we were able to manipulate and measure mitochondrial reactive oxygen species (mitoROS) signaling of individual mitochondria as well as neuronal activity of single neurons in vivo. Using this approach, we provide evidence supporting a novel role for mitoROS signaling in dendrites of excitatory glutamatergic C. elegans interneurons. Specifically, we show that following neuronal activity, dendritic mitochondria take up calcium (Ca2+) via the mitochondrial Ca2+ uniporter (MCU-1) that results in an upregulation of mitoROS production. We also observed that mitochondria are positioned in close proximity to synaptic clusters of GLR-1, the C. elegans ortholog of the AMPA subtype of glutamate receptors that mediate neuronal excitation. We show that synaptic recruitment of GLR-1 is upregulated when MCU-1 function is pharmacologically or genetically impaired but is downregulated by mitoROS signaling. Thus, signaling from postsynaptic mitochondria may regulate excitatory synapse function to maintain neuronal homeostasis by preventing excitotoxicity and energy depletion.
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Affiliation(s)
- Rachel L Doser
- Department of Biomedical Science, Colorado State UniversityFort CollinsUnited States
- Department of Health and Exercise Sciences, Colorado State UniversityFort CollinsUnited States
| | - Kaz M Knight
- Department of Biomedical Science, Colorado State UniversityFort CollinsUnited States
- Cellular and Molecular Biology Graduate Program, Colorado State UniversityFort CollinsUnited States
| | - Ennis W Deihl
- Department of Biomedical Science, Colorado State UniversityFort CollinsUnited States
| | - Frederic J Hoerndli
- Department of Biomedical Science, Colorado State UniversityFort CollinsUnited States
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6
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Sun C, Zhu L, Qin H, Su H, Zhang J, Wang S, Xu X, Zhao Z, Mao G, Chen J. Inhibition of mitochondrial calcium uptake by Ru360 enhances the effect of 1800 MHz radio-frequency electromagnetic fields on DNA damage. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 264:115472. [PMID: 37716072 DOI: 10.1016/j.ecoenv.2023.115472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 09/01/2023] [Accepted: 09/11/2023] [Indexed: 09/18/2023]
Abstract
Today, the existence of radio-frequency electromagnetic fields (RF-EMF) emitted from cell phones, wireless routers, base stations, and other sources are everywhere around our living environment, and the dose is increasing. RF-EMF have been reported to be cytotoxic and supposed to be a risk factor for various human diseases, thus, more attention is necessary. In recent years, interfere with mitochondrial calcium uptake by using mitochondrial calcium uniporter (MCU) inhibitor were suggested to be potential clinical treatment in mitochondrial calcium overload diseases, like neurodegeneration, ischemia/reperfusion injury, and cancer, but whether this approach increases the health risk of RF-EMF exposure are unknown. To address our concern, we did a preliminary study to determine whether inhibition of MCU will increase the genotoxicity of RF-EMF exposure in cells, and found that short-time (15 min) exposure to 1800 MHz RF-EMF induced significant DNA damage and cell apoptosis in mouse embryonic fibroblasts (MEFs) treated with Ruthenium 360 (Ru360), a specific inhibitor of MCU, but no significant effects on cell cycle, cell proliferation, or cell viability were observed. In conclusion, our results indicated that inhibiting MCU increases the genotoxicity of RF-EMF exposure, and more attention needs to be paid to the possible health impact of RF-EMF exposure under these treatments.
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Affiliation(s)
- Chuan Sun
- Zhejiang Provincial Key Lab of Geriatrics & Geriatrics Institute of Zhejiang Province, Department of Geriatrics, Zhejiang Hospital, Hangzhou, China.
| | - Longtao Zhu
- Bioelectromagnetics Laboratory, Zhejiang University School of Medicine, Hangzhou, China
| | - Houbing Qin
- Department of Respiratory Medicine, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Huili Su
- Zhejiang Provincial Key Lab of Geriatrics & Geriatrics Institute of Zhejiang Province, Department of Geriatrics, Zhejiang Hospital, Hangzhou, China
| | - Jing Zhang
- Zhejiang Provincial Key Lab of Geriatrics & Geriatrics Institute of Zhejiang Province, Department of Geriatrics, Zhejiang Hospital, Hangzhou, China
| | - Sanying Wang
- Zhejiang Provincial Key Lab of Geriatrics & Geriatrics Institute of Zhejiang Province, Department of Geriatrics, Zhejiang Hospital, Hangzhou, China
| | - Xiaogang Xu
- Zhejiang Provincial Key Lab of Geriatrics & Geriatrics Institute of Zhejiang Province, Department of Geriatrics, Zhejiang Hospital, Hangzhou, China
| | - Zhenlei Zhao
- Zhejiang Provincial Key Lab of Geriatrics & Geriatrics Institute of Zhejiang Province, Department of Geriatrics, Zhejiang Hospital, Hangzhou, China
| | - Genxiang Mao
- Zhejiang Provincial Key Lab of Geriatrics & Geriatrics Institute of Zhejiang Province, Department of Geriatrics, Zhejiang Hospital, Hangzhou, China.
| | - Jun Chen
- Zhejiang Provincial Key Lab of Geriatrics & Geriatrics Institute of Zhejiang Province, Department of Geriatrics, Zhejiang Hospital, Hangzhou, China.
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7
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Dridi H, Santulli G, Bahlouli L, Miotto MC, Weninger G, Marks AR. Mitochondrial Calcium Overload Plays a Causal Role in Oxidative Stress in the Failing Heart. Biomolecules 2023; 13:1409. [PMID: 37759809 PMCID: PMC10527470 DOI: 10.3390/biom13091409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/13/2023] [Accepted: 09/17/2023] [Indexed: 09/29/2023] Open
Abstract
Heart failure is a serious global health challenge, affecting more than 6.2 million people in the United States and is projected to reach over 8 million by 2030. Independent of etiology, failing hearts share common features, including defective calcium (Ca2+) handling, mitochondrial Ca2+ overload, and oxidative stress. In cardiomyocytes, Ca2+ not only regulates excitation-contraction coupling, but also mitochondrial metabolism and oxidative stress signaling, thereby controlling the function and actual destiny of the cell. Understanding the mechanisms of mitochondrial Ca2+ uptake and the molecular pathways involved in the regulation of increased mitochondrial Ca2+ influx is an ongoing challenge in order to identify novel therapeutic targets to alleviate the burden of heart failure. In this review, we discuss the mechanisms underlying altered mitochondrial Ca2+ handling in heart failure and the potential therapeutic strategies.
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Affiliation(s)
- Haikel Dridi
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians & Surgeons, New York, NY 10032, USA; (L.B.); (M.C.M.); (G.W.); (A.R.M.)
| | - Gaetano Santulli
- Department of Medicine, Division of Cardiology, Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, New York, NY 10461, USA;
| | - Laith Bahlouli
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians & Surgeons, New York, NY 10032, USA; (L.B.); (M.C.M.); (G.W.); (A.R.M.)
| | - Marco C. Miotto
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians & Surgeons, New York, NY 10032, USA; (L.B.); (M.C.M.); (G.W.); (A.R.M.)
| | - Gunnar Weninger
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians & Surgeons, New York, NY 10032, USA; (L.B.); (M.C.M.); (G.W.); (A.R.M.)
| | - Andrew R. Marks
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians & Surgeons, New York, NY 10032, USA; (L.B.); (M.C.M.); (G.W.); (A.R.M.)
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8
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Cheng H, Perkins GA, Ju S, Kim K, Ellisman MH, Pamenter ME. Enhanced mitochondrial buffering prevents Ca 2+ overload in naked mole-rat brain. J Physiol 2023:10.1113/JP285002. [PMID: 37668020 PMCID: PMC10912373 DOI: 10.1113/jp285002] [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: 05/10/2023] [Accepted: 08/16/2023] [Indexed: 09/06/2023] Open
Abstract
Deleterious Ca2+ accumulation is central to hypoxic cell death in the brain of most mammals. Conversely, hypoxia-mediated increases in cytosolic Ca2+ are retarded in hypoxia-tolerant naked mole-rat brain. We hypothesized that naked mole-rat brain mitochondria have an enhanced capacity to buffer exogenous Ca2+ and examined Ca2+ handling in naked mole-rat cortical tissue. We report that naked mole-rat brain mitochondria buffer >2-fold more exogenous Ca2+ than mouse brain mitochondria, and that the half-maximal inhibitory concentration (IC50 ) at which Ca2+ inhibits aerobic oxidative phosphorylation is >2-fold higher in naked mole-rat brain. The primary driving force of Ca2+ uptake is the mitochondrial membrane potential (Δψm ), and the IC50 at which Ca2+ decreases Δψm is ∼4-fold higher in naked mole-rat than mouse brain. The ability of naked mole-rat brain mitochondria to safely retain large volumes of Ca2+ may be due to ultrastructural differences that support the uptake and physical storage of Ca2+ in mitochondria. Specifically, and relative to mouse brain, naked mole-rat brain mitochondria are larger and have higher crista density and increased physical interactions between adjacent mitochondrial membranes, all of which are associated with improved energetic homeostasis and Ca2+ management. We propose that excessive Ca2+ influx into naked mole-rat brain is buffered by physical storage in large mitochondria, which would reduce deleterious Ca2+ overload and may thus contribute to the hypoxia and ischaemia-tolerance of naked mole-rat brain. KEY POINTS: Unregulated Ca2+ influx is a hallmark of hypoxic brain death; however, hypoxia-mediated Ca2+ influx into naked mole-rat brain is markedly reduced relative to mice. This is important because naked mole-rat brain is robustly tolerant against in vitro hypoxia, and because Ca2+ is a key driver of hypoxic cell death in brain. We show that in hypoxic naked mole-rat brain, oxidative capacity and mitochondrial membrane integrity are better preserved following exogenous Ca2+ stress. This is due to mitochondrial buffering of exogenous Ca2+ and is driven by a mitochondrial membrane potential-dependant mechanism. The unique ultrastructure of naked mole-rat brain mitochondria, as a large physical storage space, may support increased Ca2+ buffering and thus hypoxia-tolerance.
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Affiliation(s)
- Hang Cheng
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Guy A Perkins
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, CA, USA
| | - Saeyeon Ju
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, CA, USA
| | - Keunyoung Kim
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, CA, USA
| | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, CA, USA
- Department of Neurosciences, University of California at San Diego School of Medicine, San Diego, CA, USA
| | - Matthew E Pamenter
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, Ontario, Canada
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9
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Kumari A, Nguyen DM, Garg V. Patch-clamp technique to study mitochondrial membrane biophysics. J Gen Physiol 2023; 155:e202313347. [PMID: 37347216 PMCID: PMC10287547 DOI: 10.1085/jgp.202313347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 04/12/2023] [Accepted: 06/08/2023] [Indexed: 06/23/2023] Open
Abstract
Mitochondria are double-membrane organelles crucial for oxidative phosphorylation, enabling efficient ATP synthesis by eukaryotic cells. Both of the membranes, the highly selective inner mitochondrial membrane (IMM) and a relatively porous outer membrane (OMM), harbor a number of integral membrane proteins that help in the transport of biological molecules. These transporters are especially enriched in the IMM, where they help maintain transmembrane gradients for H+, K+, Ca2+, PO43-, and metabolites like ADP/ATP, citrate, etc. Impaired activity of these transporters can affect the efficiency of energy-transducing processes and can alter cellular redox state, leading to activation of cell-death pathways or metabolic syndromes in vivo. Although several methodologies are available to study ion flux through membrane proteins, the patch-clamp technique remains the gold standard for quantitatively analyzing electrogenic ion exchange across membranes. Direct patch-clamp recordings of mitoplasts (mitochondria devoid of outer membrane) in different modes, such as whole-mitoplast or excised-patch mode, allow researchers the opportunity to study the biophysics of mitochondrial transporters in the native membrane, in real time, in isolation from other fluxes or confounding factors due to changes in ion gradients, pH, or mitochondrial potential (ΔΨ). Here, we summarize the use of patch clamp to investigate several membrane proteins of mitochondria. We demonstrate how this technique can be reliably applied to record whole-mitoplast Ca2+ currents mediated via mitochondrial calcium uniporter or H+ currents mediated by uncoupling protein 1 and discuss critical considerations while recording currents from these small vesicles of the IMM (mitoplast diameter = 2-5 µm).
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Affiliation(s)
- Anshu Kumari
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, Baltimore, MD, USA
| | - Dung M. Nguyen
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, Baltimore, MD, USA
| | - Vivek Garg
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, Baltimore, MD, USA
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10
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MacEwen MJ, Sancak Y. Beyond the matrix: structural and physiological advancements in mitochondrial calcium signaling. Biochem Soc Trans 2023; 51:665-673. [PMID: 36960768 PMCID: PMC10212541 DOI: 10.1042/bst20220317] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/25/2023]
Abstract
Mitochondrial calcium (Ca2+) signaling has long been known to regulate diverse cellular functions, ranging from ATP production via oxidative phosphorylation, to cytoplasmic Ca2+ signaling to apoptosis. Central to mitochondrial Ca2+ signaling is the mitochondrial Ca2+ uniporter complex (MCUC) which enables Ca2+ flux from the cytosol into the mitochondrial matrix. Several pivotal discoveries over the past 15 years have clarified the identity of the proteins comprising MCUC. Here, we provide an overview of the literature on mitochondrial Ca2+ biology and highlight recent findings on the high-resolution structure, dynamic regulation, and new functions of MCUC, with an emphasis on publications from the last five years. We discuss the importance of these findings for human health and the therapeutic potential of targeting mitochondrial Ca2+ signaling.
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Affiliation(s)
| | - Yasemin Sancak
- Department of Pharmacology, University of Washington, Seattle, WA 98195, U.S.A
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Jost P, Klein F, Brand B, Wahl V, Wyatt A, Yildiz D, Boehm U, Niemeyer BA, Vaeth M, Alansary D. Acute Downregulation but Not Genetic Ablation of Murine MCU Impairs Suppressive Capacity of Regulatory CD4 T Cells. Int J Mol Sci 2023; 24:ijms24097772. [PMID: 37175478 PMCID: PMC10178810 DOI: 10.3390/ijms24097772] [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: 03/17/2023] [Revised: 04/17/2023] [Accepted: 04/20/2023] [Indexed: 05/15/2023] Open
Abstract
By virtue of mitochondrial control of energy production, reactive oxygen species (ROS) generation, and maintenance of Ca2+ homeostasis, mitochondria play an essential role in modulating T cell function. The mitochondrial Ca2+ uniporter (MCU) is the pore-forming unit in the main protein complex mediating mitochondrial Ca2+ uptake. Recently, MCU has been shown to modulate Ca2+ signals at subcellular organellar interfaces, thus fine-tuning NFAT translocation and T cell activation. The mechanisms underlying this modulation and whether MCU has additional T cell subpopulation-specific effects remain elusive. However, mice with germline or tissue-specific ablation of Mcu did not show impaired T cell responses in vitro or in vivo, indicating that 'chronic' loss of MCU can be functionally compensated in lymphocytes. The current work aimed to specifically investigate whether and how MCU influences the suppressive potential of regulatory CD4 T cells (Treg). We show that, in contrast to genetic ablation, acute siRNA-mediated downregulation of Mcu in murine Tregs results in a significant reduction both in mitochondrial Ca2+ uptake and in the suppressive capacity of Tregs, while the ratios of Treg subpopulations and the expression of hallmark transcription factors were not affected. These findings suggest that permanent genetic inactivation of MCU may result in compensatory adaptive mechanisms, masking the effects on the suppressive capacity of Tregs.
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Affiliation(s)
- Priska Jost
- Molecular Biophysics, Saarland University, 66421 Homburg, Germany
| | - Franziska Klein
- Molecular Biophysics, Saarland University, 66421 Homburg, Germany
| | - Benjamin Brand
- Würzburg Institute of Systems Immunology, Max Planck Research Group at Julius-Maximilians University of Würzburg, 97078 Würzburg, Germany
| | - Vanessa Wahl
- Experimental Pharmacology, Center for Molecular Signaling (PZMS), School of Medicine, Saarland University, 66421 Homburg, Germany
| | - Amanda Wyatt
- Experimental Pharmacology, Center for Molecular Signaling (PZMS), School of Medicine, Saarland University, 66421 Homburg, Germany
| | - Daniela Yildiz
- Experimental Pharmacology, Center for Molecular Signaling (PZMS), School of Medicine, Saarland University, 66421 Homburg, Germany
| | - Ulrich Boehm
- Experimental Pharmacology, Center for Molecular Signaling (PZMS), School of Medicine, Saarland University, 66421 Homburg, Germany
| | | | - Martin Vaeth
- Würzburg Institute of Systems Immunology, Max Planck Research Group at Julius-Maximilians University of Würzburg, 97078 Würzburg, Germany
| | - Dalia Alansary
- Molecular Biophysics, Saarland University, 66421 Homburg, Germany
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12
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Qin J, Liu L, Liu L, Zhou Z, Zhou Y, Zhang K, Wang B, Lu H, Ran J, Ma T, Zhang Y, Li Z, Liu X. The effect of regulating MCU expression on experimental ischemic brain injury. Exp Neurol 2023; 362:114329. [PMID: 36702427 DOI: 10.1016/j.expneurol.2023.114329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/16/2023] [Accepted: 01/21/2023] [Indexed: 01/25/2023]
Abstract
Mitochondrial calcium uniporter (MCU) is a critical channel for Ca2+ influx into mitochondria. The present study aimed to determine if MCU knockdown has beneficial effects on ischemic brain injury and to explore the underlying mechanisms. The present study demonstrated that MCU knockdown but not total knockout (KO) attenuated ischemia infarction volume and primary cortical neuronal cells' ischemic damage. MCU knockdown maintained mitochondrial ultrastructure, alleviated calcium overload, and reduced mitochondrial apoptosis. Moreover, MCU knockdown regulated the changes of MICU1 and MICU2 after cerebral infarction, while no changes were observed in other mitochondrial calcium handling proteins. Based on metabolomics, MCU knockdown reversed middle cerebral artery occlusion (MCAO)-induced up-regulated phosphoenolpyruvate and down-regulated GDP to protect energy metabolism after cerebral infarction. Furthermore, a total of 87 and 245 differentially expressed genes (DEGs) were detected by transcriptome sequencing among WT mice, MCU KO mice and MCU knockdown mice in the MCAO model, respectively. Then, NR4A1 was identified as one of the DEGs in different MCU expressions in vivo ischemia stroke model via transcriptomic screening and genetic validation. Furthermore, MCU knockdown downregulated the ischemia-induced upregulation of NR4A1 expression. Together, this is the further evidence that the MCU knockdown exerts a protective role after cerebral infarction by promoting calcium homeostasis, inhibiting mitochondrial apoptosis and protecting energy metabolism.
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Affiliation(s)
- Jin Qin
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, China
| | - Lijuan Liu
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, China
| | - Lin Liu
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, China
| | - Zhou Zhou
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, China
| | - Yicong Zhou
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, China
| | - Kun Zhang
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, China
| | - Binbin Wang
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, China
| | - Honglin Lu
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, China
| | - Jina Ran
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, China
| | - Tianzhao Ma
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, China
| | - Yingzhen Zhang
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, China
| | - Zhongzhong Li
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, China
| | - Xiaoyun Liu
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, China.
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13
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Torres AK, Jara C, Llanquinao J, Lira M, Cortés-Díaz D, Tapia-Rojas C. Mitochondrial Bioenergetics, Redox Balance, and Calcium Homeostasis Dysfunction with Defective Ultrastructure and Quality Control in the Hippocampus of Aged Female C57BL/6J Mice. Int J Mol Sci 2023; 24:ijms24065476. [PMID: 36982549 PMCID: PMC10056753 DOI: 10.3390/ijms24065476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/27/2023] [Accepted: 03/03/2023] [Indexed: 03/15/2023] Open
Abstract
Aging is a physiological process that generates progressive decline in many cellular functions. There are many theories of aging, and one of great importance in recent years is the mitochondrial theory of aging, in which mitochondrial dysfunction that occurs at advanced age could be responsible for the aged phenotype. In this context, there is diverse information about mitochondrial dysfunction in aging, in different models and different organs. Specifically, in the brain, different studies have shown mitochondrial dysfunction mainly in the cortex; however, until now, no study has shown all the defects in hippocampal mitochondria in aged female C57BL/6J mice. We performed a complete analysis of mitochondrial function in 3-month-old and 20-month-old (mo) female C57BL/6J mice, specifically in the hippocampus of these animals. We observed an impairment in bioenergetic function, indicated by a decrease in mitochondrial membrane potential, O2 consumption, and mitochondrial ATP production. Additionally, there was an increase in ROS production in the aged hippocampus, leading to the activation of antioxidant signaling, specifically the Nrf2 pathway. It was also observed that aged animals had deregulation of calcium homeostasis, with more sensitive mitochondria to calcium overload and deregulation of proteins related to mitochondrial dynamics and quality control processes. Finally, we observed a decrease in mitochondrial biogenesis with a decrease in mitochondrial mass and deregulation of mitophagy. These results show that during the aging process, damaged mitochondria accumulate, which could contribute to or be responsible for the aging phenotype and age-related disabilities.
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Affiliation(s)
- Angie K. Torres
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Universidad San Sebastián, Santiago 7510156, Chile
| | - Claudia Jara
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Universidad San Sebastián, Santiago 7510156, Chile
| | - Jesús Llanquinao
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Universidad San Sebastián, Santiago 7510156, Chile
| | - Matías Lira
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Universidad San Sebastián, Santiago 7510156, Chile
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Avda. Zañartu 1482, Ñuñoa, Santiago 7780272, Chile
| | - Daniela Cortés-Díaz
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Universidad San Sebastián, Santiago 7510156, Chile
| | - Cheril Tapia-Rojas
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Universidad San Sebastián, Santiago 7510156, Chile
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Avda. Zañartu 1482, Ñuñoa, Santiago 7780272, Chile
- Correspondence:
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14
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Walters GC, Usachev YM. Mitochondrial calcium cycling in neuronal function and neurodegeneration. Front Cell Dev Biol 2023; 11:1094356. [PMID: 36760367 PMCID: PMC9902777 DOI: 10.3389/fcell.2023.1094356] [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: 11/10/2022] [Accepted: 01/12/2023] [Indexed: 01/26/2023] Open
Abstract
Mitochondria are essential for proper cellular function through their critical roles in ATP synthesis, reactive oxygen species production, calcium (Ca2+) buffering, and apoptotic signaling. In neurons, Ca2+ buffering is particularly important as it helps to shape Ca2+ signals and to regulate numerous Ca2+-dependent functions including neuronal excitability, synaptic transmission, gene expression, and neuronal toxicity. Over the past decade, identification of the mitochondrial Ca2+ uniporter (MCU) and other molecular components of mitochondrial Ca2+ transport has provided insight into the roles that mitochondrial Ca2+ regulation plays in neuronal function in health and disease. In this review, we discuss the many roles of mitochondrial Ca2+ uptake and release mechanisms in normal neuronal function and highlight new insights into the Ca2+-dependent mechanisms that drive mitochondrial dysfunction in neurologic diseases including epilepsy, Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. We also consider how targeting Ca2+ uptake and release mechanisms could facilitate the development of novel therapeutic strategies for neurological diseases.
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Affiliation(s)
- Grant C. Walters
- Department of Neuroscience and Pharmacology, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
| | - Yuriy M. Usachev
- Department of Neuroscience and Pharmacology, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
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15
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Balogh M, Zhang J, Gaffney CM, Kalakuntla N, Nguyen NT, Trinh RT, Aguilar C, Pham HV, Milutinovic B, Nichols JM, Mahalingam R, Shepherd AJ. Sensory neuron dysfunction in orthotopic mouse models of colon cancer. J Neuroinflammation 2022; 19:204. [PMID: 35962398 PMCID: PMC9375288 DOI: 10.1186/s12974-022-02566-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/07/2022] [Indexed: 11/10/2022] Open
Abstract
Reports of neurological sequelae related to colon cancer are largely restricted to rare instances of paraneoplastic syndromes, due to autoimmune reactions. Systemic inflammation associated with tumor development influences sensory neuron function in other disease models, though the extent to which this occurs in colorectal cancer is unknown. We induced orthotopic colorectal cancer via orthotopic injection of two colorectal cancer cell lines (MC38 and CT26) in two different mouse strains (C57BL/6 and Balb/c, respectively). Behavioral tests of pain sensitivity and activity did not detect significant alterations in sensory sensitivity or diminished well-being throughout tumor development. However, immunohistochemistry revealed widespread reductions in intraepidermal nerve fiber density in the skin of tumor-bearing mice. Though loss of nerve fiber density was not associated with increased expression of cell injury markers in dorsal root ganglia, lumbar dorsal root ganglia neurons of tumor-bearing animals showed deficits in mitochondrial function. These neurons also had reduced cytosolic calcium levels in live-cell imaging and reduced spontaneous activity in multi-electrode array analysis. Bulk RNA sequencing of DRGs from tumor-bearing mice detected activation of gene expression pathways associated with elevated cytokine and chemokine signaling, including CXCL10. This is consistent with the detection of CXCL10 (and numerous other cytokines, chemokines and growth factors) in MC38 and CT26 cell-conditioned media, and the serum of tumor-bearing mice. Our study demonstrates in a pre-clinical setting that colon cancer is associated with latent sensory neuron dysfunction and implicates cytokine/chemokine signaling in this process. These findings may have implications for determining risk factors and treatment responsiveness related to neuropathy in colorectal cancer.
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Affiliation(s)
- Mihály Balogh
- The MD Anderson Pain Research Consortium and the Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.,Pharmaceutical Analysis, Groningen Research Institute of Pharmacy, University of Groningen, 9700 AD, Groningen, The Netherlands
| | - Jixiang Zhang
- The MD Anderson Pain Research Consortium and the Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Caitlyn M Gaffney
- The MD Anderson Pain Research Consortium and the Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Neha Kalakuntla
- The MD Anderson Pain Research Consortium and the Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Nicholas T Nguyen
- The MD Anderson Pain Research Consortium and the Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.,Graduate School of Biomedical Sciences, UT Southwestern Medical Center, Dallas, TX, USA
| | - Ronnie T Trinh
- The MD Anderson Pain Research Consortium and the Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Clarissa Aguilar
- The MD Anderson Pain Research Consortium and the Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.,Neuroscience and Behavior Graduate Program, University of Massachusetts Amherst, Amherst, MA, USA
| | - Hoang Vu Pham
- The MD Anderson Pain Research Consortium and the Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Bojana Milutinovic
- The MD Anderson Pain Research Consortium and the Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.,Department of Neurosurgery, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - James M Nichols
- The MD Anderson Pain Research Consortium and the Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Rajasekaran Mahalingam
- The MD Anderson Pain Research Consortium and the Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Andrew J Shepherd
- The MD Anderson Pain Research Consortium and the Laboratories of Neuroimmunology, Department of Symptom Research, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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16
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Zhao S, Zhang J, Sun X, Yangzom C, Shang P. Mitochondrial calcium uniporter involved in foodborne mycotoxin-induced hepatotoxicity. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 237:113535. [PMID: 35461028 DOI: 10.1016/j.ecoenv.2022.113535] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/28/2022] [Accepted: 04/14/2022] [Indexed: 06/14/2023]
Abstract
Foodborne mycotoxins are toxic metabolites that are produced by fungi. The widespread contamination of food and its by-products by mycotoxins is a global food safety problem that potentially threatens public health and other exposed animals. Most foodborne mycotoxins induce hepatotoxicity. However, only few studies have investigated the regulatory mechanisms of mitochondrial calcium transport monomers in mycotoxin-induced hepatotoxicity. Therefore, according to relevant studies and reports, this review suggests that intracellular Ca(2 +) homeostasis and mitochondrial Ca(2 +) uniporter are involved in the regulation of mycotoxin-induced hepatotoxicity. This review provides some ideas for future research involving mitochondrial Ca(2 +) uniporter in the molecular targets of mycotoxin-induced hepatotoxicity, as well as a reference for the research and development of related drugs and the treatment of related diseases.
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Affiliation(s)
- Shunwang Zhao
- College of Animal Science, Tibet Agriculture and Animal Husbandry College, Linzhi, Tibet, People's Republic of China; The Provincial and Ministerial co-founded collaborative innovation center for R & D in Tibet characteristic Agricultural and Animal Husbandry resources, People's Republic of China
| | - Jian Zhang
- College of Animal Science, Tibet Agriculture and Animal Husbandry College, Linzhi, Tibet, People's Republic of China; The Provincial and Ministerial co-founded collaborative innovation center for R & D in Tibet characteristic Agricultural and Animal Husbandry resources, People's Republic of China
| | - Xueqian Sun
- College of Animal Science, Tibet Agriculture and Animal Husbandry College, Linzhi, Tibet, People's Republic of China; The Provincial and Ministerial co-founded collaborative innovation center for R & D in Tibet characteristic Agricultural and Animal Husbandry resources, People's Republic of China
| | - Chamba Yangzom
- College of Animal Science, Tibet Agriculture and Animal Husbandry College, Linzhi, Tibet, People's Republic of China; The Provincial and Ministerial co-founded collaborative innovation center for R & D in Tibet characteristic Agricultural and Animal Husbandry resources, People's Republic of China
| | - Peng Shang
- College of Animal Science, Tibet Agriculture and Animal Husbandry College, Linzhi, Tibet, People's Republic of China; The Provincial and Ministerial co-founded collaborative innovation center for R & D in Tibet characteristic Agricultural and Animal Husbandry resources, People's Republic of China.
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17
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Chapa-Dubocq XR, Garcia-Baez JF, Bazil JN, Javadov S. Crosstalk between adenine nucleotide transporter and mitochondrial swelling: experimental and computational approaches. Cell Biol Toxicol 2022:10.1007/s10565-022-09724-2. [PMID: 35606662 DOI: 10.1007/s10565-022-09724-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 05/10/2022] [Indexed: 11/30/2022]
Abstract
Mitochondrial metabolism and function are modulated by changes in matrix Ca2+. Small increases in the matrix Ca2+ stimulate mitochondrial bioenergetics, whereas excessive Ca2+ leads to cell death by causing massive matrix swelling and impairing the structural and functional integrity of mitochondria. Sustained opening of the non-selective mitochondrial permeability transition pores (PTP) is the main mechanism responsible for mitochondrial Ca2+ overload that leads to mitochondrial dysfunction and cell death. Recent studies suggest the existence of two or more types of PTP, and adenine nucleotide translocator (ANT) and FOF1-ATP synthase were proposed to form the PTP independent of each other. Here, we elucidated the role of ANT in PTP opening by applying both experimental and computational approaches. We first developed and corroborated a detailed model of the ANT transport mechanism including the matrix (ANTM), cytosolic (ANTC), and pore (ANTP) states of the transporter. Then, the ANT model was incorporated into a simple, yet effective, empirical model of mitochondrial bioenergetics to ascertain the point when Ca2+ overload initiates PTP opening via an ANT switch-like mechanism activated by matrix Ca2+ and is inhibited by extra-mitochondrial ADP. We found that encoding a heterogeneous Ca2+ response of at least three types of PTPs, weakly, moderately, and strongly sensitive to Ca2+, enabled the model to simulate Ca2+ release dynamics observed after large boluses were administered to a population of energized cardiac mitochondria. Thus, this study demonstrates the potential role of ANT in PTP gating and proposes a novel mechanism governing the cryptic nature of the PTP phenomenon.
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Affiliation(s)
- Xavier R Chapa-Dubocq
- Department of Physiology, University of Puerto Rico School of Medicine, San Juan, PR, 00936-5067, USA
| | - Jorge F Garcia-Baez
- Department of Physiology, University of Puerto Rico School of Medicine, San Juan, PR, 00936-5067, USA
| | - Jason N Bazil
- Department of Physiology, Michigan State University, East Lansing, MI, 48824-1046, USA
| | - Sabzali Javadov
- Department of Physiology, University of Puerto Rico School of Medicine, San Juan, PR, 00936-5067, USA.
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18
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Pérez-Liébana I, Juaristi I, González-Sánchez P, González-Moreno L, Rial E, Podunavac M, Zakarian A, Molgó J, Vallejo-Illarramendi A, Mosqueira-Martín L, Lopez de Munain A, Pardo B, Satrústegui J, Del Arco A. A Ca 2+-Dependent Mechanism Boosting Glycolysis and OXPHOS by Activating Aralar-Malate-Aspartate Shuttle, upon Neuronal Stimulation. J Neurosci 2022; 42:3879-3895. [PMID: 35387872 PMCID: PMC9097769 DOI: 10.1523/jneurosci.1463-21.2022] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 12/20/2021] [Accepted: 01/27/2022] [Indexed: 01/18/2023] Open
Abstract
Calcium is an important second messenger regulating a bioenergetic response to the workloads triggered by neuronal activation. In embryonic mouse cortical neurons using glucose as only fuel, activation by NMDA elicits a strong workload (ATP demand)-dependent on Na+ and Ca2+ entry, and stimulates glucose uptake, glycolysis, pyruvate and lactate production, and oxidative phosphorylation (OXPHOS) in a Ca2+-dependent way. We find that Ca2+ upregulation of glycolysis, pyruvate levels, and respiration, but not glucose uptake, all depend on Aralar/AGC1/Slc25a12, the mitochondrial aspartate-glutamate carrier, component of the malate-aspartate shuttle (MAS). MAS activation increases glycolysis, pyruvate production, and respiration, a process inhibited in the presence of BAPTA-AM, suggesting that the Ca2+ binding motifs in Aralar may be involved in the activation. Mitochondrial calcium uniporter (MCU) silencing had no effect, indicating that none of these processes required MCU-dependent mitochondrial Ca2+ uptake. The neuronal respiratory response to carbachol was also dependent on Aralar, but not on MCU. We find that mouse cortical neurons are endowed with a constitutive ER-to-mitochondria Ca2+ flow maintaining basal cell bioenergetics in which ryanodine receptors, RyR2, rather than InsP3R, are responsible for Ca2+ release, and in which MCU does not participate. The results reveal that, in neurons using glucose, MCU does not participate in OXPHOS regulation under basal or stimulated conditions, while Aralar-MAS appears as the major Ca2+-dependent pathway tuning simultaneously glycolysis and OXPHOS to neuronal activation.SIGNIFICANCE STATEMENT Neuronal activation increases cell workload to restore ion gradients altered by activation. Ca2+ is involved in matching increased workload with ATP production, but the mechanisms are still unknown. We find that glycolysis, pyruvate production, and neuronal respiration are stimulated on neuronal activation in a Ca2+-dependent way, independently of effects of Ca2+ as workload inducer. Mitochondrial calcium uniporter (MCU) does not play a relevant role in Ca2+ stimulated pyruvate production and oxygen consumption as both are unchanged in MCU silenced neurons. However, Ca2+ stimulation is blunt in the absence of Aralar, a Ca2+-binding mitochondrial carrier component of Malate-Aspartate Shuttle (MAS). The results suggest that Ca2+-regulated Aralar-MAS activation upregulates glycolysis and pyruvate production, which fuels mitochondrial respiration, through regulation of cytosolic NAD+/NADH ratio.
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Affiliation(s)
- Irene Pérez-Liébana
- Departamento de Biología Molecular, Instituto Universitario de Biología Molecular -IUBM, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, 28049, Spain
| | - Inés Juaristi
- Departamento de Biología Molecular, Instituto Universitario de Biología Molecular -IUBM, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, 28049, Spain
| | - Paloma González-Sánchez
- Departamento de Biología Molecular, Instituto Universitario de Biología Molecular -IUBM, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, 28049, Spain
| | - Luis González-Moreno
- Departamento de Biología Molecular, Instituto Universitario de Biología Molecular -IUBM, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, 28049, Spain
| | - Eduardo Rial
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Margarita Salas, Madrid, 28040, Spain
| | - Maša Podunavac
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106
| | - Armen Zakarian
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106
| | - Jordi Molgó
- Université Paris-Saclay, CEA, Institut des Sciences du Vivant Frédéric Joliot, ERL Centre National de la Recherche Scientifique no. 9004, Département Médicaments et Technologies pour la Santé, Service d'Ingénierie Moléculaire pour la Santé, Gif sur Yvette, F-91191, France
| | - Ainara Vallejo-Illarramendi
- IIS Biodonostia-University of the Basque Country, Donostia, Spain; CIBERNED (institute Carlos III), Madrid, Spain; and Department of Neurology, Hospital Universitario Donostia-OSAKIDETZA, San Sebastián, 20014, Spain
| | - Laura Mosqueira-Martín
- IIS Biodonostia-University of the Basque Country, Donostia, Spain; CIBERNED (institute Carlos III), Madrid, Spain; and Department of Neurology, Hospital Universitario Donostia-OSAKIDETZA, San Sebastián, 20014, Spain
| | - Adolfo Lopez de Munain
- IIS Biodonostia-University of the Basque Country, Donostia, Spain; CIBERNED (institute Carlos III), Madrid, Spain; and Department of Neurology, Hospital Universitario Donostia-OSAKIDETZA, San Sebastián, 20014, Spain
| | - Beatriz Pardo
- Departamento de Biología Molecular, Instituto Universitario de Biología Molecular -IUBM, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, 28049, Spain
| | - Jorgina Satrústegui
- Departamento de Biología Molecular, Instituto Universitario de Biología Molecular -IUBM, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, 28049, Spain
| | - Araceli Del Arco
- Departamento de Biología Molecular, Instituto Universitario de Biología Molecular -IUBM, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain; and Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, 28049, Spain
- Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla la Mancha, Toledo, 45071 Spain; and Centro Regional de Investigaciones Biomédicas, Unidad Asociada de Biomedicina, Toledo, 45071, Spain
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19
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Verma M, Lizama BN, Chu CT. Excitotoxicity, calcium and mitochondria: a triad in synaptic neurodegeneration. Transl Neurodegener 2022; 11:3. [PMID: 35078537 PMCID: PMC8788129 DOI: 10.1186/s40035-021-00278-7] [Citation(s) in RCA: 106] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 12/29/2021] [Indexed: 02/08/2023] Open
Abstract
Glutamate is the most commonly engaged neurotransmitter in the mammalian central nervous system, acting to mediate excitatory neurotransmission. However, high levels of glutamatergic input elicit excitotoxicity, contributing to neuronal cell death following acute brain injuries such as stroke and trauma. While excitotoxic cell death has also been implicated in some neurodegenerative disease models, the role of acute apoptotic cell death remains controversial in the setting of chronic neurodegeneration. Nevertheless, it is clear that excitatory synaptic dysregulation contributes to neurodegeneration, as evidenced by protective effects of partial N-methyl-D-aspartate receptor antagonists. Here, we review evidence for sublethal excitatory injuries in relation to neurodegeneration associated with Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis and Huntington's disease. In contrast to classic excitotoxicity, emerging evidence implicates dysregulation of mitochondrial calcium handling in excitatory post-synaptic neurodegeneration. We discuss mechanisms that regulate mitochondrial calcium uptake and release, the impact of LRRK2, PINK1, Parkin, beta-amyloid and glucocerebrosidase on mitochondrial calcium transporters, and the role of autophagic mitochondrial loss in axodendritic shrinkage. Finally, we discuss strategies for normalizing the flux of calcium into and out of the mitochondrial matrix, thereby preventing mitochondrial calcium toxicity and excitotoxic dendritic loss. While the mechanisms that underlie increased uptake or decreased release of mitochondrial calcium vary in different model systems, a common set of strategies to normalize mitochondrial calcium flux can prevent excitatory mitochondrial toxicity and may be neuroprotective in multiple disease contexts.
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Affiliation(s)
- Manish Verma
- grid.21925.3d0000 0004 1936 9000Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261 USA ,grid.423286.90000 0004 0507 1326Present Address: Astellas Pharma Inc., 9 Technology Drive, Westborough, MA 01581 USA
| | - Britney N. Lizama
- grid.21925.3d0000 0004 1936 9000Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261 USA
| | - Charleen T. Chu
- grid.21925.3d0000 0004 1936 9000Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261 USA ,grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261 USA ,grid.21925.3d0000 0004 1936 9000Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261 USA ,grid.21925.3d0000 0004 1936 9000McGowan Institute for Regenerative Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261 USA ,grid.21925.3d0000 0004 1936 9000Center for Protein Conformational Diseases, University of Pittsburgh, Pittsburgh, PA 15261 USA ,grid.21925.3d0000 0004 1936 9000Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15261 USA
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20
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Wu H, Brand B, Eckstein M, Hochrein SM, Shumanska M, Dudek J, Nickel A, Maack C, Bogeski I, Vaeth M. Genetic Ablation of the Mitochondrial Calcium Uniporter (MCU) Does not Impair T Cell-Mediated Immunity In Vivo. Front Pharmacol 2022; 12:734078. [PMID: 34987384 PMCID: PMC8721163 DOI: 10.3389/fphar.2021.734078] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 11/22/2021] [Indexed: 12/11/2022] Open
Abstract
T cell activation and differentiation is associated with metabolic reprogramming to cope with the increased bioenergetic demand and to provide metabolic intermediates for the biosynthesis of building blocks. Antigen receptor stimulation not only promotes the metabolic switch of lymphocytes but also triggers the uptake of calcium (Ca2+) from the cytosol into the mitochondrial matrix. Whether mitochondrial Ca2+ influx through the mitochondrial Ca2+ uniporter (MCU) controls T cell metabolism and effector function remained, however, enigmatic. Using mice with T cell-specific deletion of MCU, we here show that genetic inactivation of mitochondrial Ca2+ uptake increased cytosolic Ca2+ levels following antigen receptor stimulation and store-operated Ca2+ entry (SOCE). However, ablation of MCU and the elevation of cytosolic Ca2+ did not affect mitochondrial respiration, differentiation and effector function of inflammatory and regulatory T cell subsets in vitro and in animal models of T cell-mediated autoimmunity and viral infection. These data suggest that MCU-mediated mitochondrial Ca2+ uptake is largely dispensable for murine T cell function. Our study has also important technical implications. Previous studies relied mostly on pharmacological inhibition or transient knockdown of mitochondrial Ca2+ uptake, but our results using mice with genetic deletion of MCU did not recapitulate these findings. The discrepancy of our study to previous reports hint at compensatory mechanisms in MCU-deficient mice and/or off-target effects of current MCU inhibitors.
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Affiliation(s)
- Hao Wu
- Würzburg Institute of Systems Immunology, Max Planck Research Group at the Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Benjamin Brand
- Würzburg Institute of Systems Immunology, Max Planck Research Group at the Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Miriam Eckstein
- Würzburg Institute of Systems Immunology, Max Planck Research Group at the Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Sophia M Hochrein
- Würzburg Institute of Systems Immunology, Max Planck Research Group at the Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Magdalena Shumanska
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Jan Dudek
- Comprehensive Heart Failure Center (CHFC), University Hospital, Julius-Maximilians University of Würzburg, Würzburg, Germany
| | - Alexander Nickel
- Comprehensive Heart Failure Center (CHFC), University Hospital, Julius-Maximilians University of Würzburg, Würzburg, Germany
| | - Christoph Maack
- Comprehensive Heart Failure Center (CHFC), University Hospital, Julius-Maximilians University of Würzburg, Würzburg, Germany
| | - Ivan Bogeski
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Martin Vaeth
- Würzburg Institute of Systems Immunology, Max Planck Research Group at the Julius-Maximilians-Universität Würzburg, Würzburg, Germany
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21
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Zhang X, Tomar N, Kandel SM, Audi SH, Cowley AW, Dash RK. Substrate- and Calcium-Dependent Differential Regulation of Mitochondrial Oxidative Phosphorylation and Energy Production in the Heart and Kidney. Cells 2021; 11:131. [PMID: 35011693 PMCID: PMC8750792 DOI: 10.3390/cells11010131] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 12/26/2021] [Accepted: 12/28/2021] [Indexed: 11/16/2022] Open
Abstract
Mitochondrial dehydrogenases are differentially stimulated by Ca2+. Ca2+ has also diverse regulatory effects on mitochondrial transporters and other enzymes. However, the consequences of these regulatory effects on mitochondrial oxidative phosphorylation (OxPhos) and ATP production, and the dependencies of these consequences on respiratory substrates, have not been investigated between the kidney and heart despite the fact that kidney energy requirements are second only to those of the heart. Our objective was, therefore, to elucidate these relationships in isolated mitochondria from the kidney outer medulla (OM) and heart. ADP-induced mitochondrial respiration was measured at different CaCl2 concentrations in the presence of various respiratory substrates, including pyruvate + malate (PM), glutamate + malate (GM), alpha-ketoglutarate + malate (AM), palmitoyl-carnitine + malate (PCM), and succinate + rotenone (SUC + ROT). The results showed that, in both heart and OM mitochondria, and for most complex I substrates, Ca2+ effects are biphasic: small increases in Ca2+ concentration stimulated, while large increases inhibited mitochondrial respiration. Furthermore, significant differences in substrate- and Ca2+-dependent O2 utilization towards ATP production between heart and OM mitochondria were observed. With PM and PCM substrates, Ca2+ showed more prominent stimulatory effects in OM than in heart mitochondria, while with GM and AM substrates, Ca2+ had similar biphasic regulatory effects in both OM and heart mitochondria. In contrast, with complex II substrate SUC + ROT, only inhibitory effects on mitochondrial respiration was observed in both the heart and the OM. We conclude that the regulatory effects of Ca2+ on mitochondrial OxPhos and ATP synthesis are biphasic, substrate-dependent, and tissue-specific.
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Affiliation(s)
- Xiao Zhang
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI 53226, USA; (X.Z.); (N.T.); (S.M.K.)
| | - Namrata Tomar
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI 53226, USA; (X.Z.); (N.T.); (S.M.K.)
| | - Sunil M. Kandel
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI 53226, USA; (X.Z.); (N.T.); (S.M.K.)
| | - Said H. Audi
- Department of Biomedical Engineering, Marquette University, Milwaukee, WI 53223, USA;
| | - Allen W. Cowley
- Center of Systems Molecular Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Ranjan K. Dash
- Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI 53226, USA; (X.Z.); (N.T.); (S.M.K.)
- Center of Systems Molecular Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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22
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Torres AK, Jara C, Park-Kang HS, Polanco CM, Tapia D, Alarcón F, de la Peña A, Llanquinao J, Vargas-Mardones G, Indo JA, Inestrosa NC, Tapia-Rojas C. Synaptic Mitochondria: An Early Target of Amyloid-β and Tau in Alzheimer's Disease. J Alzheimers Dis 2021; 84:1391-1414. [PMID: 34719499 DOI: 10.3233/jad-215139] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Alzheimer's disease (AD) is characterized by cognitive impairment and the presence of neurofibrillary tangles and senile plaques in the brain. Neurofibrillary tangles are composed of hyperphosphorylated tau, while senile plaques are formed by amyloid-β (Aβ) peptide. The amyloid hypothesis proposes that Aβ accumulation is primarily responsible for the neurotoxicity in AD. Multiple Aβ-mediated toxicity mechanisms have been proposed including mitochondrial dysfunction. However, it is unclear if it precedes Aβ accumulation or if is a consequence of it. Aβ promotes mitochondrial failure. However, amyloid β precursor protein (AβPP) could be cleaved in the mitochondria producing Aβ peptide. Mitochondrial-produced Aβ could interact with newly formed ones or with Aβ that enter the mitochondria, which may induce its oligomerization and contribute to further mitochondrial alterations, resulting in a vicious cycle. Another explanation for AD is the tau hypothesis, in which modified tau trigger toxic effects in neurons. Tau induces mitochondrial dysfunction by indirect and apparently by direct mechanisms. In neurons mitochondria are classified as non-synaptic or synaptic according to their localization, where synaptic mitochondrial function is fundamental supporting neurotransmission and hippocampal memory formation. Here, we focus on synaptic mitochondria as a primary target for Aβ toxicity and/or formation, generating toxicity at the synapse and contributing to synaptic and memory impairment in AD. We also hypothesize that phospho-tau accumulates in mitochondria and triggers dysfunction. Finally, we discuss that synaptic mitochondrial dysfunction occur in aging and correlates with age-related memory loss. Therefore, synaptic mitochondrial dysfunction could be a predisposing factor for AD or an early marker of its onset.
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Affiliation(s)
- Angie K Torres
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebasti´n Sede Los Leones, Santiago, Chile.,Centro de Envejecimiento y Regeneración (CARE), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Claudia Jara
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebasti´n Sede Los Leones, Santiago, Chile
| | - Han S Park-Kang
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebasti´n Sede Los Leones, Santiago, Chile
| | - Catalina M Polanco
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebasti´n Sede Los Leones, Santiago, Chile
| | - Diego Tapia
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebasti´n Sede Los Leones, Santiago, Chile
| | - Fabián Alarcón
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebasti´n Sede Los Leones, Santiago, Chile
| | - Adely de la Peña
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebasti´n Sede Los Leones, Santiago, Chile
| | - Jesus Llanquinao
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebasti´n Sede Los Leones, Santiago, Chile
| | - Gabriela Vargas-Mardones
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebasti´n Sede Los Leones, Santiago, Chile
| | - Javiera A Indo
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebasti´n Sede Los Leones, Santiago, Chile
| | - Nibaldo C Inestrosa
- Centro de Envejecimiento y Regeneración (CARE), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
| | - Cheril Tapia-Rojas
- Laboratory of Neurobiology of Aging, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebasti´n Sede Los Leones, Santiago, Chile
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23
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Abstract
The uptake of calcium into and extrusion of calcium from the mitochondrial matrix is a fundamental biological process that has critical effects on cellular metabolism, signaling, and survival. Disruption of mitochondrial calcium (mCa2+) cycling is implicated in numerous acquired diseases such as heart failure, stroke, neurodegeneration, diabetes, and cancer, and is genetically linked to several inherited neuromuscular disorders. Understanding the mechanisms responsible for mCa2+ exchange therefore holds great promise for the treatment of these diseases. The past decade has seen the genetic identification of many of the key proteins that mediate mitochondrial calcium uptake and efflux. Here, we present an overview of the phenomenon of mCa2+ transport, and a comprehensive examination of the molecular machinery that mediates calcium flux across the inner mitochondrial membrane: the mitochondrial uniporter complex (consisting of MCU, EMRE, MICU1, MICU2, MICU3, MCUB, and MCUR1), NCLX, LETM1, the mitochondrial ryanodine receptor, and the mitochondrial permeability transition pore. We then consider the physiological implications of mCa2+ flux and evaluate how alterations in mCa2+ homeostasis contribute to human disease. This review concludes by highlighting opportunities and challenges for therapeutic intervention in pathologies characterized by aberrant mCa2+ handling and by summarizing critical unanswered questions regarding the biology of mCa2+ flux.
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Affiliation(s)
- Joanne F Garbincius
- Center for Translational Medicine, Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
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24
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Pallafacchina G, Zanin S, Rizzuto R. From the Identification to the Dissection of the Physiological Role of the Mitochondrial Calcium Uniporter: An Ongoing Story. Biomolecules 2021; 11:biom11060786. [PMID: 34071006 PMCID: PMC8224590 DOI: 10.3390/biom11060786] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 05/14/2021] [Accepted: 05/20/2021] [Indexed: 12/16/2022] Open
Abstract
The notion of mitochondria being involved in the decoding and shaping of intracellular Ca2+ signals has been circulating since the end of the 19th century. Despite that, the molecular identity of the channel that mediates Ca2+ ion transport into mitochondria remained elusive for several years. Only in the last decade, the genes and pathways responsible for the mitochondrial uptake of Ca2+ began to be cloned and characterized. The gene coding for the pore-forming unit of the mitochondrial channel was discovered exactly 10 years ago, and its product was called mitochondrial Ca2+ uniporter or MCU. Before that, only one of its regulators, the mitochondria Ca2+ uptake regulator 1, MICU1, has been described in 2010. However, in the following years, the scientific interest in mitochondrial Ca2+ signaling regulation and physiological role has increased. This shortly led to the identification of many of its components, to the description of their 3D structure, and the characterization of the uniporter contribution to tissue physiology and pathology. In this review, we will summarize the most relevant achievements in the history of mitochondrial Ca2+ studies, presenting a chronological overview of the most relevant and landmarking discoveries. Finally, we will explore the impact of mitochondrial Ca2+ signaling in the context of muscle physiology, highlighting the recent advances in understanding the role of the MCU complex in the control of muscle trophism and metabolism.
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Affiliation(s)
- Giorgia Pallafacchina
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
- Neuroscience Institute, Italian National Research Council (CNR), 35131 Padua, Italy
- Correspondence: (G.P.); (R.R.); Tel.: +39-049-827-6029 (G.P.); +39-049-827-3001 (R.R.)
| | - Sofia Zanin
- Department of Immunology, Infectiology and Haematology, Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, 75015 Paris, France;
| | - Rosario Rizzuto
- Neuroscience Institute, Italian National Research Council (CNR), 35131 Padua, Italy
- Correspondence: (G.P.); (R.R.); Tel.: +39-049-827-6029 (G.P.); +39-049-827-3001 (R.R.)
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25
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Mitochondrial calcium uniporter is essential for hearing and hair cell preservation in congenic FVB/NJ mice. Sci Rep 2021; 11:9660. [PMID: 33958614 PMCID: PMC8102556 DOI: 10.1038/s41598-021-88841-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 04/13/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial Ca2+ regulates a wide range of cell processes, including morphogenesis, metabolism, excitotoxicity, and survival. In cochlear hair cells, the activation of mechano-electrical transduction and voltage-gated Ca2+ channels result in a large influx of Ca2+. The intracellular rise in Ca2+ is partly balanced by the mitochondria which rapidly uptakes Ca2+ via a highly selective channel comprised of the main pore-forming subunit, the mitochondrial Ca2+ uniporter (MCU), and associated regulatory proteins. MCU thus contributes to Ca2+ buffering, ensuring cytosolic homeostasis, and is posited to have a critical role in hair cell function and hearing. To test this hypothesis, Ca2+ homeostasis in hair cells and cochlear function were investigated in FVB/NJ mice carrying the knockout allele of Mcu (Mcu+/− or Mcu−/−). The Mcu knockout allele, which originated in C57BL/6 strain cosegregated along with Cdh23ahl allele to the FVB/NJ strain, due to the close proximity of these genes. Neither Mcu+/− nor Mcu−/− genotypes affected cochlear development, morphology, or Ca2+ homeostasis of auditory hair cells in the first two postnatal weeks. However, Mcu−/− mice displayed high-frequency hearing impairment as early as 3 weeks postnatal, which then progressed to profound hearing loss at all frequencies in about 6 months. In Mcu+/− mice, significantly elevated ABR thresholds were observed at 6 months and 9 months of age only at 32 kHz frequency. In three-month-old Mcu−/− mice, up to 18% of the outer hair cells and occasionally some inner hair cells were missing in the mid-cochlear region. In conclusion, mitochondrial Ca2+ uniporter is not required for the development of cochlea in mice, but is essential for hearing and hair cell preservation in congenic FVB/NJ mice.
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26
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Datta S, Jaiswal M. Mitochondrial calcium at the synapse. Mitochondrion 2021; 59:135-153. [PMID: 33895346 DOI: 10.1016/j.mito.2021.04.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 03/28/2021] [Accepted: 04/13/2021] [Indexed: 12/15/2022]
Abstract
Mitochondria are dynamic organelles, which serve various purposes, including but not limited to the production of ATP and various metabolites, buffering ions, acting as a signaling hub, etc. In recent years, mitochondria are being seen as the central regulators of cellular growth, development, and death. Since neurons are highly specialized cells with a heavy metabolic demand, it is not surprising that neurons are one of the most mitochondria-rich cells in an animal. At synapses, mitochondrial function and dynamics is tightly regulated by synaptic calcium. Calcium influx during synaptic activity causes increased mitochondrial calcium influx leading to an increased ATP production as well as buffering of synaptic calcium. While increased ATP production is required during synaptic transmission, calcium buffering by mitochondria is crucial to prevent faulty neurotransmission and excitotoxicity. Interestingly, mitochondrial calcium also regulates the mobility of mitochondria within synapses causing mitochondria to halt at the synapse during synaptic transmission. In this review, we summarize the various roles of mitochondrial calcium at the synapse.
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Affiliation(s)
- Sayantan Datta
- Tata Institute of Fundamental Research, Hyderabad, India
| | - Manish Jaiswal
- Tata Institute of Fundamental Research, Hyderabad, India.
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27
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Huntington TE, Srinivasan R. Astrocytic mitochondria in adult mouse brain slices show spontaneous calcium influx events with unique properties. Cell Calcium 2021; 96:102383. [PMID: 33676316 DOI: 10.1016/j.ceca.2021.102383] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/07/2021] [Accepted: 02/21/2021] [Indexed: 12/17/2022]
Abstract
Astrocytes govern critical aspects of brain function via spontaneous calcium signals in their soma and processes. A significant proportion of these spontaneous astrocytic calcium events are associated with mitochondria, however, the extent, sources, or kinetics of astrocytic mitochondrial calcium influx have not been studied in the adult mouse brain. To measure calcium influx into astrocytic mitochondria in situ, we generated an adeno-associated virus (AAV) with the astrocyte-specific GfaABC1D promoter driving expression of the genetically encoded calcium indicator, GCaMP6f tagged to mito7, a mitochondrial matrix targeted signal sequence. Using this construct, we observed AAV-mediated expression of GCaMP6f in adult mouse astrocytic mitochondria that co-localized with MitoTracker deep red (MTDR) in the dorsolateral striatum (DLS) and in the hippocampal stratum radiatum (HPC). Astrocytic mitochondria co-labeled with MTDR and GCaMP6f displayed robust, spontaneous calcium influx events in situ, with subcellular differences in calcium influx kinetics between somatic, branch, and branchlet mitochondria, and inter-regional differences between mitochondria in DLS and HPC astrocytes. Calcium influx into astrocytic mitochondria was strongly dependent on endoplasmic reticulum calcium stores, but did not require the mitochondrial calcium uniporter, MCU. Exposure to either glutamate, D1 or D2 dopamine receptor agonists increased calcium influx in some mitochondria, while simultaneously decreasing calcium influx in other mitochondria from the same astrocyte. These findings show that astrocytic mitochondria possess unique properties with regard to their subcellular morphology, mechanisms of calcium influx, and responses to neurotransmitter receptor agonists. Our results have important implications for understanding the role of astrocytic mitochondria during pathological processes.
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Affiliation(s)
- Taylor E Huntington
- Department of Neuroscience & Experimental Therapeutics, Texas A&M College of Medicine, Bryan, TX 77807, USA; Texas A&M Institute for Neuroscience (TAMIN), Texas A&M University, College Station, TX 77843, USA
| | - Rahul Srinivasan
- Department of Neuroscience & Experimental Therapeutics, Texas A&M College of Medicine, Bryan, TX 77807, USA; Texas A&M Institute for Neuroscience (TAMIN), Texas A&M University, College Station, TX 77843, USA.
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28
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Rysted JE, Lin Z, Walters GC, Rauckhorst AJ, Noterman M, Liu G, Taylor EB, Strack S, Usachev YM. Distinct properties of Ca 2+ efflux from brain, heart and liver mitochondria: The effects of Na +, Li + and the mitochondrial Na +/Ca 2+ exchange inhibitor CGP37157. Cell Calcium 2021; 96:102382. [PMID: 33684833 DOI: 10.1016/j.ceca.2021.102382] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/15/2021] [Accepted: 02/18/2021] [Indexed: 10/22/2022]
Abstract
Mitochondrial Ca2+ transport is essential for regulating cell bioenergetics, Ca2+ signaling and cell death. Mitochondria accumulate Ca2+ via the mitochondrial Ca2+ uniporter (MCU), whereas Ca2+ is extruded by the mitochondrial Na+/Ca2+ (mtNCX) and H+/Ca2+ exchangers. The balance between these processes is essential for preventing toxic mitochondrial Ca2+ overload. Recent work demonstrated that MCU activity varies significantly among tissues, likely reflecting tissue-specific Ca2+ signaling and energy needs. It is less clear whether this diversity in MCU activity is matched by tissue-specific diversity in mitochondrial Ca2+ extrusion. Here we compared properties of mitochondrial Ca2+ extrusion in three tissues with prominent mitochondria function: brain, heart and liver. At the transcript level, expression of the Na+/Ca2+/Li+ exchanger (NCLX), which has been proposed to mediate mtNCX transport, was significantly greater in liver than in brain or heart. At the functional level, Na+ robustly activated Ca2+ efflux from brain and heart mitochondria, but not from liver mitochondria. The mtNCX inhibitor CGP37157 blocked Ca2+ efflux from brain and heart mitochondria but had no effect in liver mitochondria. Replacement of Na+ with Li+ to test the involvement of NCLX, resulted in a slowing of mitochondrial Ca2+ efflux by ∼70 %. Collectively, our findings suggest that mtNCX is responsible for Ca2+ extrusion from the mitochondria of the brain and heart, but plays only a small, if any, role in mitochondria of the liver. They also reveal that Li+ is significantly less effective than Na+ in driving mitochondrial Ca2+ efflux.
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Affiliation(s)
- Jacob E Rysted
- Department of Neuroscience and Pharmacology and Iowa Neuroscience Institute, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Zhihong Lin
- Department of Neuroscience and Pharmacology and Iowa Neuroscience Institute, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Grant C Walters
- Department of Neuroscience and Pharmacology and Iowa Neuroscience Institute, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Adam J Rauckhorst
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Maria Noterman
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Guanghao Liu
- Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Eric B Taylor
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology and Iowa Neuroscience Institute, University of Iowa College of Medicine, Iowa City, IA, 52242, USA
| | - Yuriy M Usachev
- Department of Neuroscience and Pharmacology and Iowa Neuroscience Institute, University of Iowa College of Medicine, Iowa City, IA, 52242, USA.
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29
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Abstract
Mitochondria are responsible for ATP production but are also known as regulators of cell death, and mitochondrial matrix Ca2+ is a key modulator of both ATP production and cell death. Although mitochondrial Ca2+ uptake and efflux have been studied for over 50 years, it is only in the past decade that the proteins responsible for mitochondrial Ca2+ uptake and efflux have been identified. The identification of the mitochondrial Ca2+ uniporter (MCU) led to an explosion of studies identifying regulators of the MCU. The levels of these regulators vary in a tissue- and disease-specific manner, providing new insight into how mitochondrial Ca2+ is regulated. This review focuses on the proteins responsible for mitochondrial transport and what we have learned from mouse studies with genetic alterations in these proteins.
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Affiliation(s)
- Elizabeth Murphy
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Charles Steenbergen
- Department of Pathology, Johns Hopkins Medicine, Baltimore, Maryland 21287, USA
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The effect of DS16570511, a new inhibitor of mitochondrial calcium uniporter, on calcium homeostasis, metabolism, and functional state of cultured cortical neurons and isolated brain mitochondria. Biochim Biophys Acta Gen Subj 2021; 1865:129847. [PMID: 33453305 DOI: 10.1016/j.bbagen.2021.129847] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/20/2020] [Accepted: 01/11/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND Disorders of mitochondrial Ca2+ homeostasis play a key role in the glutamate excitotoxicity of brain neurons. DS16570511 (DS) is a new penetrating inhibitor of mitochondrial Ca2+ uniporter complex (MCUC). The paper examines the effects of DS on the cultivated cortical neurons and isolated mitochondria of the rat brain. METHODS The functions of neurons and mitochondria were examined using fluorescence microscopy, XF24 microplate-based сell respirometry, ion-selective microelectrodes, spectrophotometry, and polarographic technique. RESULTS At the doses of 30 and 45 μM, DS reliably slowed down the onset of glutamate-induced delayed calcium deregulation of neurons and suppressed their death. 30 μM DS caused hyperpolarization of mitochondria of resting neurons, and 45 μM DS temporarily depolarized neuronal mitochondria. It was also demonstrated that 30-60 μM DS stimulated cellular respiration. DS was shown to suppress Ca2+ uptake by isolated brain mitochondria. In addition, DS inhibited ADP-stimulated mitochondrial respiration and ADP-induced decrease in the mitochondrial membrane potential. It was found that DS inhibited the activity of complex II of the respiratory chain. In the presence of Ca2+, high DS concentrations caused a collapse of the mitochondrial membrane potential. CONCLUSIONS The data obtained indicate that, in addition to the inhibition of MCUC, DS affects the main energy-transducing functions of mitochondria. GENERAL SIGNIFICANCE The using DS as a tool for studying MCUC and its functional role in neuronal cells should be done with care, bearing in mind multiple effects of DS, a proper evaluation of which would require multivariate analysis.
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Hamilton J, Brustovetsky T, Brustovetsky N. The effect of mitochondrial calcium uniporter and cyclophilin D knockout on resistance of brain mitochondria to Ca 2+-induced damage. J Biol Chem 2021; 296:100669. [PMID: 33864812 PMCID: PMC8131324 DOI: 10.1016/j.jbc.2021.100669] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/10/2021] [Accepted: 04/13/2021] [Indexed: 12/14/2022] Open
Abstract
The mitochondrial calcium uniporter (MCU) and cyclophilin D (CyD) are key players in induction of the permeability transition pore (PTP), which leads to mitochondrial depolarization and swelling, the major signs of Ca2+-induced mitochondrial damage. Mitochondrial depolarization inhibits ATP production, whereas swelling results in the release of mitochondrial pro-apoptotic proteins. The extent to which simultaneous deletion of MCU and CyD inhibits PTP induction and prevents damage of brain mitochondria is not clear. Here, we investigated the effects of MCU and CyD deletion on the propensity for PTP induction using mitochondria isolated from the brains of MCU-KO, CyD-KO, and newly created MCU/CyD-double knockout (DKO) mice. Neither deletion of MCU nor of CyD affected respiration or membrane potential in mitochondria isolated from the brains of these mice. Mitochondria from MCU-KO and MCU/CyD-DKO mice displayed reduced Ca2+ uptake and diminished extent of PTP induction. The Ca2+ uptake by mitochondria from CyD-KO mice was increased compared with mitochondria from WT mice. Deletion of CyD prevented mitochondrial swelling and resulted in transient depolarization in response to Ca2+, but it did not prevent Ca2+-induced delayed mitochondrial depolarization. Mitochondria from MCU/CyD-DKO mice did not swell in response to Ca2+, but they did exhibit mild sustained depolarization. Dibucaine, an inhibitor of the Ca2+-activated mitochondrial phospholipase A2, attenuated and bovine serum albumin completely eliminated the sustained depolarization. This suggests the involvement of phospholipase A2 and free fatty acids. Thus, in addition to induction of the classical PTP, alternative deleterious mechanisms may contribute to mitochondrial damage following exposure to elevated Ca2+.
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Affiliation(s)
- James Hamilton
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Tatiana Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Nickolay Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA.
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Faizan MI, Ahmad T. Altered mitochondrial calcium handling and cell death by necroptosis: An emerging paradigm. Mitochondrion 2020; 57:47-62. [PMID: 33340710 DOI: 10.1016/j.mito.2020.12.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/24/2020] [Accepted: 12/10/2020] [Indexed: 12/13/2022]
Abstract
The classical necroptosis signaling is mediated by death receptors (DRs) that work in synergy with traditional caspase inhibitory signals. Currently, potential therapeutic molecules are in various phases of clinical trials for a spectrum of pathological conditions associated with necroptosis. However, a non-classical model of necroptosis has also emerged over the last decade with a relatively unexplored molecular mechanism. Although in vitro studies and preclinical models have shown its close association with mitochondrial dysfunction (mito-dysfunction), contradictory reports have emerged which complicate its definitiveness. Though impaired mitochondrial calcium ([Ca2+]m) handling is established in necrotic cell death, how this interplay regulates necroptosis is yet to be elucidated. Taking these questions into consideration, we have discussed various molecular aspects of necroptosis with the emerging role of mito-dysfunction. Based on the central role of altered [Ca2+]m handling in mito-dysfunction mediated necroptosis, we have provided a comprehensive molecular insight into this emerging paradigm. Potential reasons for the contradictory findings regarding the role of mito-dysfunction in necroptosis in general and mitochondrial-dependent necroptosis in specific are discussed. We also provide insights into the current understanding of how [Ca2+]m can be a critical determinant in deciding the cell fate under certain pathological conditions, while under others it may be dispensable. Lastly, we have highlighted the key molecular targets which have a direct implication for therapeutic intervention in conditions that are associated with impaired [Ca2+]m handling and cell death by necroptosis.
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Affiliation(s)
- Md Imam Faizan
- Multidisciplinary Centre for Advanced Research & Studies, Jamia Millia Islamia, New Delhi 110025 India
| | - Tanveer Ahmad
- Multidisciplinary Centre for Advanced Research & Studies, Jamia Millia Islamia, New Delhi 110025 India.
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Yang CH, Lee KH, Ho WK, Lee SH. Inter-spike mitochondrial Ca 2+ release enhances high frequency synaptic transmission. J Physiol 2020; 599:1567-1594. [PMID: 33140422 DOI: 10.1113/jp280351] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 10/27/2020] [Indexed: 01/03/2023] Open
Abstract
KEY POINTS Presynaptic mitochondria not only absorb but also release Ca2+ during high frequency stimulation (HFS) when presynaptic [Ca2+ ] is kept low (<500 nm) by high cytosolic Ca2+ buffer or strong plasma membrane calcium clearance mechanisms under physiological external [Ca2+ ]. Mitochondrial Ca2+ release (MCR) does not alter the global presynaptic Ca2+ transients. MCR during HFS enhances short-term facilitation and steady state excitatory postsynaptic currents by increasing vesicular release probability. The intra-train MCR may provide residual calcium at interspike intervals, and thus support high frequency neurotransmission at central glutamatergic synapses. ABSTRACT Emerging evidence indicates that mitochondrial Ca2+ buffering contributes to local regulation of synaptic transmission. It is unknown, however, whether mitochondrial Ca2+ release (MCR) occurs during high frequency synaptic transmission. Confirming the previous notion that 2 μm tetraphenylphosphonium (TPP+ ) is a specific inhibitor of the mitochondrial Na+ /Ca2+ exchanger (mNCX), we studied the role of MCR via mNCX in short-term plasticity during high frequency stimulation (HFS) at the calyx of Held synapse of the rat. TPP+ reduced short-term facilitation (STF) and steady state excitatory postsynaptic currents during HFS at mature calyx synapses under physiological extracellular [Ca2+ ] ([Ca2+ ]o = 1.2 mm), but not at immature calyx or at 2 mm [Ca2+ ]o . The inhibitory effects of TPP+ were stronger at synapses with morphologically complex calyces harbouring many swellings and at 32°C than at simple calyx synapses and at room temperature. These effects of TPP+ on STF were well correlated with those on the presynaptic mitochondrial [Ca2+ ] build-up during HFS. Mitochondrial [Ca2+ ] during HFS was increased by TPP+ at mature calyces under 1.2 mm [Ca2+ ]o , and further enhanced at 32°C, but not under 2 mm [Ca2+ ]o or at immature calyces. The close correlation of the effects of TPP+ on mitochondrial [Ca2+ ] with those on STF suggests that mNCX contributes to STF at the calyx of Held synapses. The intra-train MCR enhanced vesicular release probability without altering global presynaptic [Ca2+ ]. Our results suggest that MCR during HFS elevates local [Ca2+ ] near synaptic sites at interspike intervals to enhance STF and to support stable synaptic transmission under physiological [Ca2+ ]o .
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Affiliation(s)
- Che Ho Yang
- Department of Physiology, Cell Physiology Lab., Seoul National University College of Medicine and Neuroscience Research Institute, Seoul National University Medical Research Centre, Seoul, Republic of Korea
| | - Kyu-Hee Lee
- Department of Physiology, Cell Physiology Lab., Seoul National University College of Medicine and Neuroscience Research Institute, Seoul National University Medical Research Centre, Seoul, Republic of Korea
| | - Won-Kyung Ho
- Department of Physiology, Cell Physiology Lab., Seoul National University College of Medicine and Neuroscience Research Institute, Seoul National University Medical Research Centre, Seoul, Republic of Korea.,Department of Brain and Cognitive Science, Seoul National University, Seoul, Republic of Korea
| | - Suk-Ho Lee
- Department of Physiology, Cell Physiology Lab., Seoul National University College of Medicine and Neuroscience Research Institute, Seoul National University Medical Research Centre, Seoul, Republic of Korea.,Department of Brain and Cognitive Science, Seoul National University, Seoul, Republic of Korea
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Calvo-Rodriguez M, Bacskai BJ. Mitochondria and Calcium in Alzheimer's Disease: From Cell Signaling to Neuronal Cell Death. Trends Neurosci 2020; 44:136-151. [PMID: 33160650 DOI: 10.1016/j.tins.2020.10.004] [Citation(s) in RCA: 118] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/03/2020] [Accepted: 10/07/2020] [Indexed: 02/06/2023]
Abstract
Mitochondrial dysfunction has been implicated in the pathogenesis of almost all neurological diseases, including Alzheimer's disease (AD). Historically, a primary focus in this context has been the link between mitochondrial dynamics and amyloid β toxicity. Recent evidence suggests that dysregulation of mitochondrial calcium homeostasis is also related to tau and other risk factors in AD, although an ongoing challenge in the field is that data collected from different models or experimental settings have not always been consistent. We examine recent literature on mitochondrial dysregulation in AD, with special emphasis on mitochondrial calcium. We include data from in vitro systems, genetic animal models, and AD-derived human tissue, and discuss whether mitochondrial calcium transporters should be proposed as therapeutic candidates for the development of neuroprotective drugs against AD.
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Affiliation(s)
- Maria Calvo-Rodriguez
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 114 16th Street, Charlestown, MA 02129, USA
| | - Brian J Bacskai
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 114 16th Street, Charlestown, MA 02129, USA.
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Bisbach CM, Hutto RA, Poria D, Cleghorn WM, Abbas F, Vinberg F, Kefalov VJ, Hurley JB, Brockerhoff SE. Mitochondrial Calcium Uniporter (MCU) deficiency reveals an alternate path for Ca 2+ uptake in photoreceptor mitochondria. Sci Rep 2020; 10:16041. [PMID: 32994451 PMCID: PMC7525533 DOI: 10.1038/s41598-020-72708-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 09/04/2020] [Indexed: 01/18/2023] Open
Abstract
Rods and cones use intracellular Ca2+ to regulate many functions, including phototransduction and neurotransmission. The Mitochondrial Calcium Uniporter (MCU) complex is thought to be the primary pathway for Ca2+ entry into mitochondria in eukaryotes. We investigate the hypothesis that mitochondrial Ca2+ uptake via MCU influences phototransduction and energy metabolism in photoreceptors using a mcu-/- zebrafish and a rod photoreceptor-specific Mcu-/- mouse. Using genetically encoded Ca2+ sensors to directly examine Ca2+ uptake in zebrafish cone mitochondria, we found that loss of MCU reduces but does not eliminate mitochondrial Ca2+ uptake. Loss of MCU does not lead to photoreceptor degeneration, mildly affects mitochondrial metabolism, and does not alter physiological responses to light, even in the absence of the Na+/Ca2+, K+ exchanger. Our results reveal that MCU is dispensable for vertebrate photoreceptor function, consistent with its low expression and the presence of an alternative pathway for Ca2+ uptake into photoreceptor mitochondria.
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Affiliation(s)
- Celia M Bisbach
- Biochemistry Department, University of Washington, Seattle, WA, USA
| | - Rachel A Hutto
- Biochemistry Department, University of Washington, Seattle, WA, USA
| | - Deepak Poria
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | | | - Fatima Abbas
- Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Frans Vinberg
- Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Vladimir J Kefalov
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - James B Hurley
- Biochemistry Department, University of Washington, Seattle, WA, USA
- Ophthalmology Department, University of Washington, Seattle, WA, USA
| | - Susan E Brockerhoff
- Biochemistry Department, University of Washington, Seattle, WA, USA.
- Ophthalmology Department, University of Washington, Seattle, WA, USA.
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Mitochondrial Calcium Deregulation in the Mechanism of Beta-Amyloid and Tau Pathology. Cells 2020; 9:cells9092135. [PMID: 32967303 PMCID: PMC7564294 DOI: 10.3390/cells9092135] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/18/2020] [Accepted: 09/19/2020] [Indexed: 02/06/2023] Open
Abstract
Aggregation and deposition of β-amyloid and/or tau protein are the key neuropathological features in neurodegenerative disorders such as Alzheimer's disease (AD) and other tauopathies including frontotemporal dementia (FTD). The interaction between oxidative stress, mitochondrial dysfunction and the impairment of calcium ions (Ca2+) homeostasis induced by misfolded tau and β-amyloid plays an important role in the progressive neuronal loss occurring in specific areas of the brain. In addition to the control of bioenergetics and ROS production, mitochondria are fine regulators of the cytosolic Ca2+ homeostasis that induce vital signalling mechanisms in excitable cells such as neurons. Impairment in the mitochondrial Ca2+ uptake through the mitochondrial Ca2+ uniporter (MCU) or release through the Na+/Ca2+ exchanger may lead to mitochondrial Ca2+ overload and opening of the permeability transition pore inducing neuronal death. Recent evidence suggests an important role for these mechanisms as the underlying causes for neuronal death in β-amyloid and tau pathology. The present review will focus on the mechanisms that lead to cytosolic and especially mitochondrial Ca2+ disturbances occurring in AD and tau-induced FTD, and propose possible therapeutic interventions for these disorders.
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Huo J, Lu S, Kwong JQ, Bround MJ, Grimes KM, Sargent MA, Brown ME, Davis ME, Bers DM, Molkentin JD. MCUb Induction Protects the Heart From Postischemic Remodeling. Circ Res 2020; 127:379-390. [PMID: 32299299 PMCID: PMC7367751 DOI: 10.1161/circresaha.119.316369] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
RATIONALE Mitochondrial Ca2+ loading augments oxidative metabolism to match functional demands during times of increased work or injury. However, mitochondrial Ca2+ overload also directly causes mitochondrial rupture and cardiomyocyte death during ischemia-reperfusion injury by inducing mitochondrial permeability transition pore opening. The MCU (mitochondrial Ca2+ uniporter) mediates mitochondrial Ca2+ influx, and its activity is modulated by partner proteins in its molecular complex, including the MCUb subunit. OBJECTIVE Here, we sought to examine the function of the MCUb subunit of the MCU-complex in regulating mitochondria Ca2+ influx dynamics, acute cardiac injury, and long-term adaptation after ischemic injury. METHODS AND RESULTS Cardiomyocyte-specific MCUb overexpressing transgenic mice and Mcub gene-deleted (Mcub-/-) mice were generated to dissect the molecular function of this protein in the heart. We observed that MCUb protein is undetectable in the adult mouse heart at baseline, but mRNA and protein are induced after ischemia-reperfusion injury. MCUb overexpressing mice demonstrated inhibited mitochondrial Ca2+ uptake in cardiomyocytes and partial protection from ischemia-reperfusion injury by reducing mitochondrial permeability transition pore opening. Antithetically, deletion of the Mcub gene exacerbated pathological cardiac remodeling and infarct expansion after ischemic injury in association with greater mitochondrial Ca2+ uptake. Furthermore, hindlimb remote ischemic preconditioning induced MCUb expression in the heart, which was associated with decreased mitochondrial Ca2+ uptake, collectively suggesting that induction of MCUb protein in the heart is protective. Similarly, mouse embryonic fibroblasts from Mcub-/- mice were more sensitive to Ca2+ overload. CONCLUSIONS Our studies suggest that Mcub is a protective cardiac inducible gene that reduces mitochondrial Ca2+ influx and permeability transition pore opening after ischemic injury to reduce ongoing pathological remodeling.
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Affiliation(s)
- Jiuzhou Huo
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, OH (J.H., M.J.B., K.M.G., M.A.S., J.D.M.)
| | - Shan Lu
- Department of Pharmacology, University of California, Davis (S.L., D.M.B.)
| | - Jennifer Q Kwong
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA (J.Q.K.)
| | - Michael J Bround
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, OH (J.H., M.J.B., K.M.G., M.A.S., J.D.M.)
| | - Kelly M Grimes
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, OH (J.H., M.J.B., K.M.G., M.A.S., J.D.M.)
| | - Michelle A Sargent
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, OH (J.H., M.J.B., K.M.G., M.A.S., J.D.M.)
| | - Milton E Brown
- Wallace H. Coulter Department of Biomedical Engineering, Emory University School of Medicine, Atlanta, GA (M.E.B., M.E.D.)
| | - Michael E Davis
- Wallace H. Coulter Department of Biomedical Engineering, Emory University School of Medicine, Atlanta, GA (M.E.B., M.E.D.)
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis (S.L., D.M.B.)
| | - Jeffery D Molkentin
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, OH (J.H., M.J.B., K.M.G., M.A.S., J.D.M.)
- Howard Hughes Medical Institute, Cincinnati Children's Hospital Medical Center, OH (J.D.M.)
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Chvanov M, Voronina S, Zhang X, Telnova S, Chard R, Ouyang Y, Armstrong J, Tanton H, Awais M, Latawiec D, Sutton R, Criddle DN, Tepikin AV. Knockout of the Mitochondrial Calcium Uniporter Strongly Suppresses Stimulus-Metabolism Coupling in Pancreatic Acinar Cells but Does Not Reduce Severity of Experimental Acute Pancreatitis. Cells 2020; 9:cells9061407. [PMID: 32516955 PMCID: PMC7349284 DOI: 10.3390/cells9061407] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/28/2020] [Accepted: 06/01/2020] [Indexed: 12/13/2022] Open
Abstract
Acute pancreatitis is a frequent disease that lacks specific drug treatment. Unravelling the molecular mechanisms of acute pancreatitis is essential for the development of new therapeutics. Several inducers of acute pancreatitis trigger sustained Ca2+ increases in the cytosol and mitochondria of pancreatic acinar cells. The mitochondrial calcium uniporter (MCU) mediates mitochondrial Ca2+ uptake that regulates bioenergetics and plays an important role in cell survival, damage and death. Aberrant Ca2+ signaling and mitochondrial damage in pancreatic acinar cells have been implicated in the initiation of acute pancreatitis. The primary aim of this study was to assess the involvement of the MCU in experimental acute pancreatitis. We found that pancreatic acinar cells from MCU-/- mice display dramatically reduced mitochondrial Ca2+ uptake. This is consistent with the drastic changes of stimulus-metabolism coupling, manifested by the reduction of mitochondrial NADH/FAD+ responses to cholecystokinin and in the decrease of cholecystokinin-stimulated oxygen consumption. However, in three experimental models of acute pancreatitis (induced by caerulein, taurolithocholic acid 3-sulfate or palmitoleic acid plus ethanol), MCU knockout failed to reduce the biochemical and histological changes characterizing the severity of local and systemic damage. A possible explanation of this surprising finding is the redundancy of damaging mechanisms activated by the inducers of acute pancreatitis.
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Affiliation(s)
- Michael Chvanov
- Department of Cellular and Molecular Physiology, University of Liverpool, Liverpool L69 3BX, UK; (S.V.); (S.T.); (R.C.); (Y.O.); (H.T.); (D.N.C)
- Correspondence: (M.C.); (A.V.T.); Tel.: +44-(0)15-1794-5357 (M.C.); +44-(0)15-1794-5351 (A.V.T.)
| | - Svetlana Voronina
- Department of Cellular and Molecular Physiology, University of Liverpool, Liverpool L69 3BX, UK; (S.V.); (S.T.); (R.C.); (Y.O.); (H.T.); (D.N.C)
| | - Xiaoying Zhang
- Liverpool Pancreatitis Research Group, Royal Liverpool University Hospital, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK; (X.Z.); (J.A.); (M.A.); (D.L.); (R.S.)
| | - Svetlana Telnova
- Department of Cellular and Molecular Physiology, University of Liverpool, Liverpool L69 3BX, UK; (S.V.); (S.T.); (R.C.); (Y.O.); (H.T.); (D.N.C)
| | - Robert Chard
- Department of Cellular and Molecular Physiology, University of Liverpool, Liverpool L69 3BX, UK; (S.V.); (S.T.); (R.C.); (Y.O.); (H.T.); (D.N.C)
| | - Yulin Ouyang
- Department of Cellular and Molecular Physiology, University of Liverpool, Liverpool L69 3BX, UK; (S.V.); (S.T.); (R.C.); (Y.O.); (H.T.); (D.N.C)
| | - Jane Armstrong
- Liverpool Pancreatitis Research Group, Royal Liverpool University Hospital, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK; (X.Z.); (J.A.); (M.A.); (D.L.); (R.S.)
| | - Helen Tanton
- Department of Cellular and Molecular Physiology, University of Liverpool, Liverpool L69 3BX, UK; (S.V.); (S.T.); (R.C.); (Y.O.); (H.T.); (D.N.C)
| | - Muhammad Awais
- Liverpool Pancreatitis Research Group, Royal Liverpool University Hospital, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK; (X.Z.); (J.A.); (M.A.); (D.L.); (R.S.)
| | - Diane Latawiec
- Liverpool Pancreatitis Research Group, Royal Liverpool University Hospital, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK; (X.Z.); (J.A.); (M.A.); (D.L.); (R.S.)
| | - Robert Sutton
- Liverpool Pancreatitis Research Group, Royal Liverpool University Hospital, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK; (X.Z.); (J.A.); (M.A.); (D.L.); (R.S.)
| | - David N. Criddle
- Department of Cellular and Molecular Physiology, University of Liverpool, Liverpool L69 3BX, UK; (S.V.); (S.T.); (R.C.); (Y.O.); (H.T.); (D.N.C)
| | - Alexei V. Tepikin
- Department of Cellular and Molecular Physiology, University of Liverpool, Liverpool L69 3BX, UK; (S.V.); (S.T.); (R.C.); (Y.O.); (H.T.); (D.N.C)
- Correspondence: (M.C.); (A.V.T.); Tel.: +44-(0)15-1794-5357 (M.C.); +44-(0)15-1794-5351 (A.V.T.)
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Hosseini M, Wilson RH, Crouzet C, Amirhekmat A, Wei KS, Akbari Y. Resuscitating the Globally Ischemic Brain: TTM and Beyond. Neurotherapeutics 2020; 17:539-562. [PMID: 32367476 PMCID: PMC7283450 DOI: 10.1007/s13311-020-00856-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrest (CA) afflicts ~ 550,000 people each year in the USA. A small fraction of CA sufferers survive with a majority of these survivors emerging in a comatose state. Many CA survivors suffer devastating global brain injury with some remaining indefinitely in a comatose state. The pathogenesis of global brain injury secondary to CA is complex. Mechanisms of CA-induced brain injury include ischemia, hypoxia, cytotoxicity, inflammation, and ultimately, irreversible neuronal damage. Due to this complexity, it is critical for clinicians to have access as early as possible to quantitative metrics for diagnosing injury severity, accurately predicting outcome, and informing patient care. Current recommendations involve using multiple modalities including clinical exam, electrophysiology, brain imaging, and molecular biomarkers. This multi-faceted approach is designed to improve prognostication to avoid "self-fulfilling" prophecy and early withdrawal of life-sustaining treatments. Incorporation of emerging dynamic monitoring tools such as diffuse optical technologies may provide improved diagnosis and early prognostication to better inform treatment. Currently, targeted temperature management (TTM) is the leading treatment, with the number of patients needed to treat being ~ 6 in order to improve outcome for one patient. Future avenues of treatment, which may potentially be combined with TTM, include pharmacotherapy, perfusion/oxygenation targets, and pre/postconditioning. In this review, we provide a bench to bedside approach to delineate the pathophysiology, prognostication methods, current targeted therapies, and future directions of research surrounding hypoxic-ischemic brain injury (HIBI) secondary to CA.
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Affiliation(s)
- Melika Hosseini
- Department of Neurology, School of Medicine, University of California, Irvine, USA
| | - Robert H Wilson
- Department of Neurology, School of Medicine, University of California, Irvine, USA
- Beckman Laser Institute, University of California, Irvine, USA
| | - Christian Crouzet
- Department of Neurology, School of Medicine, University of California, Irvine, USA
- Beckman Laser Institute, University of California, Irvine, USA
| | - Arya Amirhekmat
- Department of Neurology, School of Medicine, University of California, Irvine, USA
| | - Kevin S Wei
- Department of Neurology, School of Medicine, University of California, Irvine, USA
| | - Yama Akbari
- Department of Neurology, School of Medicine, University of California, Irvine, USA.
- Beckman Laser Institute, University of California, Irvine, USA.
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40
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Li X, Spelat R, Bartolini A, Cesselli D, Ius T, Skrap M, Caponnetto F, Manini I, Yang Y, Torre V. Mechanisms of malignancy in glioblastoma cells are linked to mitochondrial Ca 2 + uniporter upregulation and higher intracellular Ca 2+ levels. J Cell Sci 2020; 133:jcs.237503. [PMID: 32051286 DOI: 10.1242/jcs.237503] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 01/28/2020] [Indexed: 01/13/2023] Open
Abstract
Glioblastoma (GBM) is one of the most malignant brain tumours and, despite advances in treatment modalities, it remains largely incurable. Ca2+ regulation and dynamics play crucial roles in different aspects of cancer, but they have never been investigated in detail in GBM. Here, we report that spontaneous Ca2+ waves in GBM cells cause unusual intracellular Ca2+ ([Ca2+]i) elevations (>1 μM), often propagating through tumour microtubes (TMs) connecting adjacent cells. This unusual [Ca2+]i elevation is not associated with the induction of cell death and is concomitant with overexpression of mitochondrial Ca2+ uniporter (MCU). We show that MCU silencing decreases proliferation and alters [Ca2+]i dynamics in U87 GBM cells, while MCU overexpression increases [Ca2+]i elevation in human astrocytes (HAs). These results suggest that changes in the expression level of MCU, a protein involved in intracellular Ca2+ regulation, influences GBM cell proliferation, contributing to GBM malignancy.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Xiaoyun Li
- Neurobiology Sector, International School for Advanced Studies (SISSA), 34136 Trieste, Italy
| | - Renza Spelat
- Neurobiology Sector, International School for Advanced Studies (SISSA), 34136 Trieste, Italy
| | - Anna Bartolini
- Institute of Pathology, University Hospital of Udine, 33100 Udine, Italy
| | - Daniela Cesselli
- Institute of Pathology, University Hospital of Udine, 33100 Udine, Italy.,Department of Medicine, University of Udine, 33100 Udine, Italy
| | - Tamara Ius
- Neurosurgery Unit, Department of Neurosciences, University Hospital of Udine, 33100 Udine, Italy
| | - Miran Skrap
- Neurosurgery Unit, Department of Neurosciences, University Hospital of Udine, 33100 Udine, Italy
| | | | - Ivana Manini
- Department of Medicine, University of Udine, 33100 Udine, Italy
| | - Yili Yang
- Joint SISSA-ISM Laboratory, Suzhou Institute of Systems Medicine, Chinese Academy of Medical Sciences, 215000 Suzhou, Jiangsu, China
| | - Vincent Torre
- Neurobiology Sector, International School for Advanced Studies (SISSA), 34136 Trieste, Italy .,Joint SISSA-ISM Laboratory, Suzhou Institute of Systems Medicine, Chinese Academy of Medical Sciences, 215000 Suzhou, Jiangsu, China
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41
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Szibor M, Gizatullina Z, Gainutdinov T, Endres T, Debska-Vielhaber G, Kunz M, Karavasili N, Hallmann K, Schreiber F, Bamberger A, Schwarzer M, Doenst T, Heinze HJ, Lessmann V, Vielhaber S, Kunz WS, Gellerich FN. Cytosolic, but not matrix, calcium is essential for adjustment of mitochondrial pyruvate supply. J Biol Chem 2020; 295:4383-4397. [PMID: 32094224 PMCID: PMC7135991 DOI: 10.1074/jbc.ra119.011902] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/19/2020] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) and cellular workload are tightly balanced by the key cellular regulator, calcium (Ca2+). Current models assume that cytosolic Ca2+ regulates workload and that mitochondrial Ca2+ uptake precedes activation of matrix dehydrogenases, thereby matching OXPHOS substrate supply to ATP demand. Surprisingly, knockout (KO) of the mitochondrial Ca2+ uniporter (MCU) in mice results in only minimal phenotypic changes and does not alter OXPHOS. This implies that adaptive activation of mitochondrial dehydrogenases by intramitochondrial Ca2+ cannot be the exclusive mechanism for OXPHOS control. We hypothesized that cytosolic Ca2+, but not mitochondrial matrix Ca2+, may adapt OXPHOS to workload by adjusting the rate of pyruvate supply from the cytosol to the mitochondria. Here, we studied the role of malate-aspartate shuttle (MAS)-dependent substrate supply in OXPHOS responses to changing Ca2+ concentrations in isolated brain and heart mitochondria, synaptosomes, fibroblasts, and thymocytes from WT and MCU KO mice and the isolated working rat heart. Our results indicate that extramitochondrial Ca2+ controls up to 85% of maximal pyruvate-driven OXPHOS rates, mediated by the activity of the complete MAS, and that intramitochondrial Ca2+ accounts for the remaining 15%. Of note, the complete MAS, as applied here, included besides its classical NADH oxidation reaction the generation of cytosolic pyruvate. Part of this largely neglected mechanism has previously been described as the “mitochondrial gas pedal.” Its implementation into OXPHOS control models integrates seemingly contradictory results and warrants a critical reappraisal of metabolic control mechanisms in health and disease.
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Affiliation(s)
- Marten Szibor
- Faculty of Medicine and Health Technology, Tampere University, FI-33520 Tampere, Finland.,Department of Cardiothoracic Surgery, Jena University Hospital, D-07747 Jena, Germany
| | - Zemfira Gizatullina
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany.,Leibniz-Institute for Neurobiology, D-39120 Magdeburg, Germany
| | - Timur Gainutdinov
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany.,Leibniz-Institute for Neurobiology, D-39120 Magdeburg, Germany.,Research Institute for Problems of Ecology and Mineral Wealth Use, Tatarstan Academy of Sciences, Kazan 420087, Russia
| | - Thomas Endres
- Faculty of Medicine and Health Technology, Tampere University, FI-33520 Tampere, Finland
| | | | - Matthias Kunz
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany
| | - Niki Karavasili
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany
| | - Kerstin Hallmann
- Department of Cardiothoracic Surgery, Jena University Hospital, D-07747 Jena, Germany
| | - Frank Schreiber
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany.,German Center for Neurodegenerative Diseases, D-39120 Magdeburg, Germany
| | - Alexandra Bamberger
- Department of Cardiothoracic Surgery, Jena University Hospital, D-07747 Jena, Germany
| | - Michael Schwarzer
- Department of Cardiothoracic Surgery, Jena University Hospital, D-07747 Jena, Germany
| | - Torsten Doenst
- Department of Cardiothoracic Surgery, Jena University Hospital, D-07747 Jena, Germany
| | - Hans-Jochen Heinze
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany.,German Center for Neurodegenerative Diseases, D-39120 Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), D-39120 Magdeburg, Germany
| | - Volkmar Lessmann
- Faculty of Medicine and Health Technology, Tampere University, FI-33520 Tampere, Finland.,Center for Behavioral Brain Sciences (CBBS), D-39120 Magdeburg, Germany
| | - Stefan Vielhaber
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany.,German Center for Neurodegenerative Diseases, D-39120 Magdeburg, Germany
| | - Wolfram S Kunz
- Department of Cardiothoracic Surgery, Jena University Hospital, D-07747 Jena, Germany
| | - Frank N Gellerich
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany .,Leibniz-Institute for Neurobiology, D-39120 Magdeburg, Germany
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42
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Ca (2+)N It Be Measured? Detection of Extramitochondrial Calcium Movement With High-Resolution FluoRespirometry. Sci Rep 2019; 9:19229. [PMID: 31848391 PMCID: PMC6917783 DOI: 10.1038/s41598-019-55618-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 11/13/2019] [Indexed: 11/24/2022] Open
Abstract
Our aim was to develop a method to detect extramitochondrial Ca2+ movement and O2 fluxes simultaneously. Using High-Resolution FluoRespirometry, we also tested whether mitochondrial permeability transition pore (mPTP) inhibition or anoxia affects the mitochondrial Ca2+ flux. Ca2+ movement evoked by CaCl2 or anoxia was assessed with CaGreen-5N dye using Blue-Fluorescence-Sensor in isolated liver mitochondria, liver homogenates and duodenal biopsies. Exogenous CaCl2 (50 µM) resulted in an abrupt elevation in CaGreen-5N fluorescence followed by a decrease (Ca2+ uptake) with simultaneous elevation in O2 consumption in liver preparations. This was followed by a rapid increase in the fluorescence signal, reaching a higher intensity (Ca2+ efflux) than that of the initial CaCl2-induced elevation. Chelation of Ca2+ with EGTA completely abolished the fluorescence of the indicator. After pre-incubation with cyclosporin A, a marked delay in Ca2+ movement was observed, not only in isolated liver mitochondria, but also in tissue homogenates. In all samples, the transition to anoxia resulted in immediate increase in the level of extramitochondrial Ca2+. The results demonstrate that the CaGreen-5N method is suitable to monitor simultaneous O2 and Ca2+ fluxes, and the opening of mPTP in various biological samples. In this system the duration of stimulated Ca2+ fluxes may provide a novel parameter to evaluate the efficacy of mPTP blocker compounds.
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43
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Soman SK, Bazała M, Keatinge M, Bandmann O, Kuznicki J. Restriction of mitochondrial calcium overload by mcu inactivation renders a neuroprotective effect in zebrafish models of Parkinson's disease. Biol Open 2019; 8:bio044347. [PMID: 31548178 PMCID: PMC6826286 DOI: 10.1242/bio.044347] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 09/13/2019] [Indexed: 12/21/2022] Open
Abstract
The loss of dopaminergic neurons (DA) is a pathological hallmark of sporadic and familial forms of Parkinson's disease (PD). We have previously shown that inhibiting mitochondrial calcium uniporter (mcu) using morpholinos can rescue DA neurons in the PTEN-induced putative kinase 1 (pink1)-/- zebrafish model of PD. In this article, we show results from our studies in mcu knockout zebrafish, which was generated using the CRISPR/Cas9 system. Functional assays confirmed impaired mitochondrial calcium influx in mcu -/- zebrafish. We also used in vivo calcium imaging and fluorescent assays in purified mitochondria to investigate mitochondrial calcium dynamics in a pink1 -/- zebrafish model of PD. Mitochondrial morphology was evaluated in DA neurons and muscle fibers using immunolabeling and transgenic lines, respectively. We observed diminished mitochondrial area in DA neurons of pink1 -/- zebrafish, while deletion of mcu restored mitochondrial area. In contrast, the mitochondrial volume in muscle fibers was not restored after inactivation of mcu in pink1 -/- zebrafish. Mitochondrial calcium overload coupled with depolarization of mitochondrial membrane potential leads to mitochondrial dysfunction in the pink1 -/- zebrafish model of PD. We used in situ hybridization and immunohistochemical labeling of DA neurons to evaluate the effect of mcu deletion on DA neuronal clusters in the ventral telencephalon of zebrafish brain. We show that DA neurons are rescued after deletion of mcu in pink1 -/- and the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) zebrafish model of PD. Thus, inactivation of mcu is protective in both genetic and chemical models of PD. Our data reveal that regulating mcu function could be an effective therapeutic target in PD pathology.
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Affiliation(s)
- Smijin K Soman
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, Księcia Trojdena 4, 02-109, Warsaw, Poland
| | - Michal Bazała
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, Księcia Trojdena 4, 02-109, Warsaw, Poland
| | - Marcus Keatinge
- Medical Research Council Centre for Developmental and Biomedical Genetics, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385a Glossop Road, Sheffield, S10 2HQ, UK
| | - Oliver Bandmann
- Medical Research Council Centre for Developmental and Biomedical Genetics, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385a Glossop Road, Sheffield, S10 2HQ, UK
| | - Jacek Kuznicki
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, Księcia Trojdena 4, 02-109, Warsaw, Poland
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The Effects of a Combination of Ion Channel Inhibitors in Female Rats Following Repeated Mild Traumatic Brain Injury. Int J Mol Sci 2018; 19:ijms19113408. [PMID: 30384417 PMCID: PMC6274967 DOI: 10.3390/ijms19113408] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 10/26/2018] [Accepted: 10/27/2018] [Indexed: 01/26/2023] Open
Abstract
Following mild traumatic brain injury (mTBI), the ionic homeostasis of the central nervous system (CNS) becomes imbalanced. Excess Ca2+ influx into cells triggers molecular cascades, which result in detrimental effects. The authors assessed the effects of a combination of ion channel inhibitors (ICI) following repeated mTBI (rmTBI). Adult female rats were subjected to two rmTBI weight-drop injuries 24 h apart, sham procedures (sham), or no procedures (normal). Lomerizine, which inhibits voltage-gated calcium channels, was administered orally twice daily, whereas YM872 and Brilliant Blue G, inhibiting α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and P2X₇ receptors, respectively, were delivered intraperitoneally every 48 h post-injury. Vehicle treatment controls were included for rmTBI, sham, and normal groups. At 11 days following rmTBI, there was a significant increase in the time taken to cross the 3 cm beam, as a sub-analysis of neurological severity score (NSS) assessments, compared with the normal control (p < 0.05), and a significant decrease in learning-associated improvement in rmTBI in Morris water maze (MWM) trials relative to the sham (p < 0.05). ICI-treated rmTBI animals were not different to sham, normal controls, or rmTBI treated with vehicle in all neurological severity score and Morris water maze assessments (p > 0.05). rmTBI resulted in increases in microglial cell density, antioxidant responses (manganese-dependent superoxide dismutase (MnSOD) immunoreactivity), and alterations to node of Ranvier structure. ICI treatment decreased microglial density, MnSOD immunoreactivity, and abnormalities of the node of Ranvier compared with vehicle controls (p < 0.01). The authors' findings demonstrate the beneficial effects of the combinatorial ICI treatment on day 11 post-rmTBI, suggesting an attractive therapeutic strategy against the damage induced by excess Ca2+ following rmTBI.
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