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de Souza IIA, da Silva Barenco T, Pavarino MEMF, Couto MT, de Resende GO, de Oliveira DF, Ponte CG, Nascimento JHM, Maciel L. A potent and selective activator of large-conductance Ca 2+-activated K + channels induces preservation of mitochondrial function after hypoxia and reoxygenation by handling of calcium and transmembrane potential. Acta Physiol (Oxf) 2024; 240:e14151. [PMID: 38676357 DOI: 10.1111/apha.14151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 02/15/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024]
Abstract
AIMS Ischaemic heart disease remains a significant cause of mortality globally. A pharmacological agent that protects cardiac mitochondria against oxygen deprivation injuries is welcome in therapy against acute myocardial infarction. Here, we evaluate the effect of large-conductance Ca2+-activated K+ channels (BKCa) activator, Compound Z, in isolated mitochondria under hypoxia and reoxygenation. METHODS Mitochondria from mice hearts were obtained by differential centrifugation. The isolated mitochondria were incubated with a BKCa channel activator, Compound Z, and subjected to normoxia or hypoxia/reoxygenation. Mitochondrial function was evaluated by measurement of O2 consumption in the complexes I, II, and IV in the respiratory states 1, 2, 3, and by maximal uncoupled O2 uptake, ATP production, ROS production, transmembrane potential, and calcium retention capacity. RESULTS Incubation of isolated mitochondria with Compound Z under normoxia conditions reduced the mitochondrial functions and induced the production of a significant amount of ROS. However, under hypoxia/reoxygenation, the Compound Z prevented a profound reduction in mitochondrial functions, including reducing ROS production over the hypoxia/reoxygenation group. Furthermore, hypoxia/reoxygenation induced a large mitochondria depolarization, which Compound Z incubation prevented, but, even so, Compound Z created a small depolarization. The mitochondrial calcium uptake was prevented by the BKCa activator, extruding the mitochondrial calcium present before Compound Z incubation. CONCLUSION The Compound Z acts as a mitochondrial BKCa channel activator and can protect mitochondria function against hypoxia/reoxygenation injury, by handling mitochondrial calcium and transmembrane potential.
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Affiliation(s)
- Itanna Isis Araujo de Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
- Programa de Pós-Graduação Em Cardiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Thais da Silva Barenco
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
- Programa de Pós-Graduação Em Cardiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | | | - Marcos Tadeu Couto
- Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro, Rio de Janeiro, Brasil
| | | | | | | | - José Hamilton Matheus Nascimento
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
- Programa de Pós-Graduação Em Cardiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
| | - Leonardo Maciel
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil
- Universidade Federal do Rio de Janeiro, Duque de Caxias, Brasil
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2
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Shen S, Wang Z, Sun H, Ma L. Role of NLRP3 Inflammasome in Myocardial Ischemia-Reperfusion Injury and Ventricular Remodeling. Med Sci Monit 2022; 28:e934255. [PMID: 35042840 PMCID: PMC8790935 DOI: 10.12659/msm.934255] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Reperfusion therapy is the optimal therapy for acute myocardial infarction (AMI), but acute inflammatory injury and chronic heart failure (HF) after myocardial ischemia and reperfusion (MI/R) remain the leading cause of death after AMI. Pyroptosis, a newly discovered form of cell death, has been proven to play a significant role in the acute reperfusion process and the subsequent chronic process of ventricular remodeling. Current research shows that multiple stimuli activate the pyroptotic signaling pathway and contribute to cell death and nonbacterial inflammation after MI/R. These stimuli promote the assembly of the nucleotide-binding and oligomerization-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome by activating NLRP3. The mature NLRP3 inflammasome cleaves procaspase-1 to active caspase-1, which leads to mature processing of interleukin (IL)-18, IL-1β, and gasdermin D (GSDMD) protein. That eventually results in cell lysis and generation of nonbacterial inflammation. The present review summarizes the mechanism of NLRP3 inflammasome activation after MI/R and discusses the role that NLRP3-mediated pyroptosis plays in the pathophysiology of MI/R injury and ventricular remodeling. We also discuss potential mechanisms and targeted therapy for which there is evidence supporting treatment of ischemic heart disease.
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Affiliation(s)
- Shichun Shen
- Department of Cardiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China (mainland)
| | - Zhen Wang
- Department of Cardiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China (mainland)
| | - Haozhong Sun
- Department of Cardiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China (mainland)
| | - Likun Ma
- Department of Cardiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China (mainland)
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3
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Nan J, Li J, Lin Y, Saif Ur Rahman M, Li Z, Zhu L. The interplay between mitochondria and store-operated Ca 2+ entry: Emerging insights into cardiac diseases. J Cell Mol Med 2021; 25:9496-9512. [PMID: 34564947 PMCID: PMC8505841 DOI: 10.1111/jcmm.16941] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 08/20/2021] [Accepted: 09/08/2021] [Indexed: 12/14/2022] Open
Abstract
Store‐operated Ca2+ entry (SOCE) machinery, including Orai channels, TRPCs, and STIM1, is key to cellular calcium homeostasis. The following characteristics of mitochondria are involved in the physiological and pathological regulation of cells: mitochondria mediate calcium uptake through calcium uniporters; mitochondria are regulated by mitochondrial dynamic related proteins (OPA1, MFN1/2, and DRP1) and form mitochondrial networks through continuous fission and fusion; mitochondria supply NADH to the electron transport chain through the Krebs cycle to produce ATP; under stress, mitochondria will produce excessive reactive oxygen species to regulate mitochondria‐endoplasmic reticulum interactions and the related signalling pathways. Both SOCE and mitochondria play critical roles in mediating cardiac hypertrophy, diabetic cardiomyopathy, and cardiac ischaemia‐reperfusion injury. All the mitochondrial characteristics mentioned above are determinants of SOCE activity, and vice versa. Ca2+ signalling dictates the reciprocal regulation between mitochondria and SOCE under the specific pathological conditions of cardiomyocytes. The coupling of mitochondria and SOCE is essential for various pathophysiological processes in the heart. Herein, we review the research focussing on the reciprocal regulation between mitochondria and SOCE and provide potential interplay patterns in cardiac diseases.
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Affiliation(s)
- Jinliang Nan
- Provincial Key Cardiovascular Research Laboratory, Department of Cardiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang Province, Hangzhou, China
| | - Jiamin Li
- Provincial Key Cardiovascular Research Laboratory, Department of Cardiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang Province, Hangzhou, China
| | - Yinuo Lin
- Wenzhou Municipal Key Cardiovascular Research Laboratory, Department of Cardiology, The First Affiliated Hospital, Wenzhou Medical University, Zhejiang Province, Wenzhou, China
| | - Muhammad Saif Ur Rahman
- Zhejiang University-University of Edinburgh Biomedical Institute, Haining, Zhejiang, China.,Clinical Research Center, The Second Affiliated Hospital Zhejiang University School of Medicine, Hangzhou, China
| | - Zhengzheng Li
- Department of Neurology, Research Institute of Experimental Neurobiology, The First Affiliated Hospital, Wenzhou Medical University, Zhejiang Province, Wenzhou, China
| | - Lingjun Zhu
- Provincial Key Cardiovascular Research Laboratory, Department of Cardiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang Province, Hangzhou, China
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4
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Poerwoatmodjo A, Schenk GJ, Geurts JJG, Luchicchi A. Cysteine Proteases and Mitochondrial Instability: A Possible Vicious Cycle in MS Myelin? Front Cell Neurosci 2020; 14:612383. [PMID: 33335477 PMCID: PMC7736044 DOI: 10.3389/fncel.2020.612383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/12/2020] [Indexed: 12/15/2022] Open
Affiliation(s)
- Anthony Poerwoatmodjo
- Division Clinical Neurosciences, Department of Anatomy and Neurosciences, Amsterdam Neuroscience, Amsterdam Universitair Medische Centra (UMC), Location Vrije Universiteit (VU) Medical Center, MS Center Amsterdam, Amsterdam, Netherlands
| | - Geert J Schenk
- Division Clinical Neurosciences, Department of Anatomy and Neurosciences, Amsterdam Neuroscience, Amsterdam Universitair Medische Centra (UMC), Location Vrije Universiteit (VU) Medical Center, MS Center Amsterdam, Amsterdam, Netherlands
| | - Jeroen J G Geurts
- Division Clinical Neurosciences, Department of Anatomy and Neurosciences, Amsterdam Neuroscience, Amsterdam Universitair Medische Centra (UMC), Location Vrije Universiteit (VU) Medical Center, MS Center Amsterdam, Amsterdam, Netherlands
| | - Antonio Luchicchi
- Division Clinical Neurosciences, Department of Anatomy and Neurosciences, Amsterdam Neuroscience, Amsterdam Universitair Medische Centra (UMC), Location Vrije Universiteit (VU) Medical Center, MS Center Amsterdam, Amsterdam, Netherlands
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5
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Yokoi K, Hisamatsu Y, Naito K, Aoki S. Design, Synthesis, and Anticancer Activities of Cyclometalated Tris(2-phenylpyridine)iridium(III) Complexes with Cationic Peptides at the 4′-Position of the 2-Phenylpyridine Ligand. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201700846] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Kenta Yokoi
- Faculty of Pharmaceutical Sciences; Tokyo University of Science; 2641Yamazaki 278-8510 Noda Chiba Japan
| | - Yosuke Hisamatsu
- Faculty of Pharmaceutical Sciences; Tokyo University of Science; 2641Yamazaki 278-8510 Noda Chiba Japan
| | - Kana Naito
- Faculty of Pharmaceutical Sciences; Tokyo University of Science; 2641Yamazaki 278-8510 Noda Chiba Japan
| | - Shin Aoki
- Faculty of Pharmaceutical Sciences; Tokyo University of Science; 2641Yamazaki 278-8510 Noda Chiba Japan
- Division of Medical-Science-Engineering Cooperation; Research Institute for Science and Technology; Tokyo University of Science; 2641Yamazaki 278-8510 Noda Chiba Japan
- Imaging Frontier Center; Research Institute for Science and Technology; Tokyo University of Science; 2641Yamazaki 278-8510 Noda Chiba Japan
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6
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Yu N, Wang S, Wang P, Li Y, Li S, Wang L, Chen H, Wang Y. The calcium uniporter regulates the permeability transition pore in isolated cortical mitochondria. Neural Regen Res 2015; 7:109-13. [PMID: 25767484 PMCID: PMC4354124 DOI: 10.3969/j.issn.1673-5374.2012.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 12/20/2011] [Indexed: 01/28/2023] Open
Abstract
To investigate the influence of the mitochondrial calcium uniporter on the mitochondrial permeability transition pore, the present study observed mitochondrial morphology in cortical neurons isolated from adult rats using transmission electron microscopy, and confirmed the morphology and activity of isolated mitochondria by detecting succinic dehydrogenase and monoamine oxidase, two mitochondrial enzymes. Isolated mitochondria were treated with either ruthenium red, an inhibitor of the uniporter, spermine, an activator of the uniporter, or in combination with cyclosporin A, an inhibitor of the mitochondrial permeability transition pore. Results showed that ruthenium red inhibited CaCl2-induced mitochondrial permeability transition pore opening, spermine enhanced opening, and cyclosporin A attenuated the effects of spermine. Results demonstrated that the mitochondrial calcium uniporter plays a role in regulating the mitochondrial permeability transition pore in mitochondria isolated from the rat brain cortex.
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Affiliation(s)
- Ning Yu
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Shilei Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Peng Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Yu Li
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Shuhong Li
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Li Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Hongbing Chen
- Cerebrovascular Disease Institute, Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Yanting Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
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7
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Altered myocardial calcium cycling and energetics in heart failure--a rational approach for disease treatment. Cell Metab 2015; 21:183-194. [PMID: 25651173 PMCID: PMC4338997 DOI: 10.1016/j.cmet.2015.01.005] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Cardiomyocyte function depends on coordinated movements of calcium into and out of the cell and the proper delivery of ATP to energy-utilizing enzymes. Defects in calcium-handling proteins and abnormal energy metabolism are features of heart failure. Recent discoveries have led to gene-based therapies targeting calcium-transporting or -binding proteins, such as the cardiac sarco(endo)plasmic reticulum calcium ATPase (SERCA2a), leading to improvements in calcium homeostasis and excitation-contraction coupling. Here we review impaired calcium cycling and energetics in heart failure, assessing their roles from both a mutually exclusive and interdependent viewpoint, and discuss therapies that may improve the failing myocardium.
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8
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Hogan QH, Sprick C, Guo Y, Mueller S, Bienengraeber M, Pan B, Wu HE. Divergent effects of painful nerve injury on mitochondrial Ca(2+) buffering in axotomized and adjacent sensory neurons. Brain Res 2014; 1589:112-25. [PMID: 25251590 DOI: 10.1016/j.brainres.2014.09.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Revised: 09/09/2014] [Accepted: 09/15/2014] [Indexed: 02/05/2023]
Abstract
Mitochondria critically regulate cytoplasmic Ca(2+) concentration ([Ca(2+)]c), but the effects of sensory neuron injury have not been examined. Using FCCP (1µM) to eliminate mitochondrial Ca(2+) uptake combined with oligomycin (10µM) to prevent ATP depletion, we first identified features of depolarization-induced neuronal [Ca(2+)]c transients that are sensitive to blockade of mitochondrial Ca(2+) buffering in order to assess mitochondrial contributions to [Ca(2+)]c regulation. This established the loss of a shoulder during the recovery of the depolarization (K(+))-induced transient, increased transient peak and area, and elevated shoulder level as evidence of diminished mitochondrial Ca(2+) buffering. We then examined transients in Control neurons and neurons from the 4th lumbar (L4) and 5th lumbar (L5) dorsal root ganglia after L5 spinal nerve ligation (SNL). The SNL L4 neurons showed decreased transient peak and area compared to control neurons, while the SNL L5 neurons showed increased shoulder level. Additionally, SNL L4 neurons developed shoulders following transients with lower peaks than Control neurons. Application of FCCP plus oligomycin elevated resting [Ca(2+)]c in SNL L4 neurons more than in Control neurons. Whereas application of FCCP plus oligomycin 2s after neuronal depolarization initiated mitochondrial Ca(2+) release in most Control and SNL L4 neurons, this usually failed to release mitochondrial Ca(2+) from SNL L5 neurons. For comparable cytoplasmic Ca(2+) loads, the releasable mitochondrial Ca(2+) in SNL L5 neurons was less than Control while it was increased in SNL L4 neurons. These findings show diminished mitochondrial Ca(2+) buffering in axotomized SNL L5 neurons but enhanced Ca(2+) buffering by neurons in adjacent SNL L4 neurons.
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Affiliation(s)
- Quinn H Hogan
- Department of Anesthesiology, Medical College of Wisconsin, 8701 W Watertown Plank, Milwaukee, WI 53226, USA; Zablocki VA Medical Center, 5000 W National Avenue, Milwaukee, WI 53295, USA
| | - Chelsea Sprick
- Department of Anesthesiology, Medical College of Wisconsin, 8701 W Watertown Plank, Milwaukee, WI 53226, USA
| | - Yuan Guo
- Department of Anesthesiology, Medical College of Wisconsin, 8701 W Watertown Plank, Milwaukee, WI 53226, USA
| | - Samantha Mueller
- Department of Anesthesiology, Medical College of Wisconsin, 8701 W Watertown Plank, Milwaukee, WI 53226, USA
| | - Martin Bienengraeber
- Department of Anesthesiology, Medical College of Wisconsin, 8701 W Watertown Plank, Milwaukee, WI 53226, USA; Department of Pharmacology and Toxicology, Medical College of Wisconsin, USA
| | - Bin Pan
- Department of Anesthesiology, Medical College of Wisconsin, 8701 W Watertown Plank, Milwaukee, WI 53226, USA
| | - Hsiang-En Wu
- Department of Anesthesiology, Medical College of Wisconsin, 8701 W Watertown Plank, Milwaukee, WI 53226, USA.
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9
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Hawrysh PJ, Buck LT. Anoxia-mediated calcium release through the mitochondrial permeability transition pore silences NMDA receptor currents in turtle neurons. ACTA ACUST UNITED AC 2014; 216:4375-87. [PMID: 24259257 DOI: 10.1242/jeb.092650] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Mammalian neurons are anoxia sensitive and rapidly undergo excitotoxic cell death when deprived of oxygen, mediated largely by Ca(2+) entry through over-activation of N-methyl-d-aspartate receptors (NMDARs). This does not occur in neurons of the anoxia-tolerant western painted turtle, where a decrease in NMDAR currents is observed with anoxia. This decrease is dependent on a modest rise in cytosolic [Ca(2+)] ([Ca(2+)]c) that is mediated by release from the mitochondria. The aim of this study was to determine whether the mitochondrial permeability transition pore (mPTP) is involved in NMDAR silencing through release of mitochondrial Ca(2+). Opening the mPTP during normoxia with atractyloside decreased NMDAR currents by releasing mitochondrial Ca(2+), indicated by an increase in Oregon Green fluorescence. Conversely, the mPTP blocker cyclosporin A prevented the anoxia-mediated increase in [Ca(2+)]c and reduction in NMDAR currents. Mitochondrial membrane potential (Ψm) was determined using rhodamine-123 fluorescence and decreased with the onset of anoxia in a time frame that coincided with the increase in [Ca(2+)]c. Activation of mitochondrial ATP-sensitive potassium (mK(+)ATP) channels also releases mitochondrial Ca(2+) and we show that activation of mK(+)ATP channels during normoxia with diazoxide leads to Ψm depolarization and inhibition with 5-hydroxydecanoic acid blocked anoxia-mediated Ψm depolarization. Ψm does not collapse during anoxia but rather reaches a new steady-state level that is maintained via ATP hydrolysis by the F1-F0 ATPase, as inhibition with oligomycin depolarizes Ψm further than the anoxic level. We conclude that anoxia activates mK(+)ATP channels, which leads to matrix depolarization, Ca(2+) release via the mPTP, and ultimately silencing of NMDARs.
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Affiliation(s)
- Peter John Hawrysh
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada, M5S 3G5
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10
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Hilgemann DW, Fine M, Linder ME, Jennings BC, Lin MJ. Massive endocytosis triggered by surface membrane palmitoylation under mitochondrial control in BHK fibroblasts. eLife 2013; 2:e01293. [PMID: 24282236 PMCID: PMC3839538 DOI: 10.7554/elife.01293] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Large Ca transients cause massive endocytosis (MEND) in BHK fibroblasts by nonclassical mechanisms. We present evidence that MEND depends on mitochondrial permeability transition pore (PTP) openings, followed by coenzyme A (CoA) release, acyl CoA synthesis, and membrane protein palmitoylation. MEND is blocked by inhibiting mitochondrial Ca uptake or PTP openings, depleting fatty acids, blocking acyl CoA synthesis, metabolizing CoA, or inhibiting palmitoylation. It is triggered by depolarizing mitochondria or promoting PTP openings. After mitochondrial MEND blockade, MEND is restored by cytoplasmic acyl CoA or CoA. MEND is blocked by siRNA knockdown of the plasmalemmal acyl transferase, DHHC5. When acyl CoA is abundant, transient H2O2 oxidative stress or PKC activation initiates MEND, but the immediate presence of H2O2 prevents MEND. The PTP inhibitor, NIM811, significantly increases plasmalemma in normally growing cells. Thus, the MEND pathway may contribute to constitutive as well as pathological plasmalemma turnover in dependence on mitochondrial stress signaling. DOI: http://dx.doi.org/10.7554/eLife.01293.001.
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Affiliation(s)
- Donald W Hilgemann
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, United States
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11
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Feng S, Li H, Tai Y, Huang J, Su Y, Abramowitz J, Zhu MX, Birnbaumer L, Wang Y. Canonical transient receptor potential 3 channels regulate mitochondrial calcium uptake. Proc Natl Acad Sci U S A 2013; 110:11011-6. [PMID: 23776229 PMCID: PMC3704010 DOI: 10.1073/pnas.1309531110] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Mitochondrial Ca(2+) homeostasis is fundamental to regulation of mitochondrial membrane potential, ATP production, and cellular Ca(2+) homeostasis. It has been known for decades that isolated mitochondria can take up Ca(2+) from the extramitochondrial solution, but the molecular identity of the Ca(2+) channels involved in this action is largely unknown. Here, we show that a fraction of canonical transient receptor potential 3 (TRPC3) channels is localized to mitochondria, a significant fraction of mitochondrial Ca(2+) uptake that relies on extramitochondrial Ca(2+) concentration is TRPC3-dependent, and the up- and down-regulation of TRPC3 expression in the cell influences the mitochondrial membrane potential. Our findings suggest that TRPC3 channels contribute to mitochondrial Ca(2+) uptake. We anticipate our observations may provide insights into the mechanisms of mitochondrial Ca(2+) uptake and advance understanding of the physiological role of TRPC3.
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Affiliation(s)
- Shengjie Feng
- Laboratory of Neural Signal Transduction, Institute of Neuroscience, Shanghai Institutes of Biological Sciences, State Key Laboratory of Neuroscience, Shanghai 200031, China
- University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Hongyu Li
- Laboratory of Neural Signal Transduction, Institute of Neuroscience, Shanghai Institutes of Biological Sciences, State Key Laboratory of Neuroscience, Shanghai 200031, China
- University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Yilin Tai
- Laboratory of Neural Signal Transduction, Institute of Neuroscience, Shanghai Institutes of Biological Sciences, State Key Laboratory of Neuroscience, Shanghai 200031, China
| | - Junbo Huang
- Laboratory of Neural Signal Transduction, Institute of Neuroscience, Shanghai Institutes of Biological Sciences, State Key Laboratory of Neuroscience, Shanghai 200031, China
- University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Yujuan Su
- Laboratory of Neural Signal Transduction, Institute of Neuroscience, Shanghai Institutes of Biological Sciences, State Key Laboratory of Neuroscience, Shanghai 200031, China
- University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Joel Abramowitz
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709; and
| | - Michael X. Zhu
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX 77030
| | - Lutz Birnbaumer
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709; and
| | - Yizheng Wang
- Laboratory of Neural Signal Transduction, Institute of Neuroscience, Shanghai Institutes of Biological Sciences, State Key Laboratory of Neuroscience, Shanghai 200031, China
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12
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Binah O, Weissman A, Itskovitz-Eldor J, Rosen MR. Integrating beat rate variability: from single cells to hearts. Heart Rhythm 2013; 10:928-932. [PMID: 23416376 DOI: 10.1016/j.hrthm.2013.02.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Indexed: 01/02/2023]
Affiliation(s)
- Ofer Binah
- Sohnis Family Stem Cells Center, Technion - Israel Institute of Technology, Haifa, Israel.,Rappaport Faculty of Medicine and Research Institute, Technion - Israel Institute of Technology, Haifa, Israel.,Department of Obstetrics and Gynecology, Rambam Health Care Campus, Haifa, Israel
| | - Amir Weissman
- Rappaport Faculty of Medicine and Research Institute, Technion - Israel Institute of Technology, Haifa, Israel.,Department of Obstetrics and Gynecology, Rambam Health Care Campus, Haifa, Israel
| | - Joseph Itskovitz-Eldor
- Sohnis Family Stem Cells Center, Technion - Israel Institute of Technology, Haifa, Israel.,Rappaport Faculty of Medicine and Research Institute, Technion - Israel Institute of Technology, Haifa, Israel.,Department of Obstetrics and Gynecology, Rambam Health Care Campus, Haifa, Israel
| | - Michael R Rosen
- Department of Pharmacology, Columbia University College of Physicians and Surgeons, New York, New York.,Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York
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13
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Rosa AO, Yamaguchi N, Morad M. Mechanical regulation of native and the recombinant calcium channel. Cell Calcium 2013; 53:264-74. [PMID: 23357406 DOI: 10.1016/j.ceca.2012.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 12/25/2012] [Indexed: 11/30/2022]
Abstract
L-type calcium channels are modulated by a host of mechanisms that include voltage, calcium ions (Ca(2+) dependent inactivation and facilitation), cytosolic proteins (CAM, CAMKII, PKA, PKC, etc.), and oxygen radicals. Here we describe yet another Ca(2+) channel regulatory mechanism that is induced by pressure-flow (PF) forces of ∼25dyn/cm(2) producing 35-60% inhibition of channel current. Only brief periods (300ms) of such PF pulses were required to suppress reversibly the current. Recombinant Ca(2+) channels (α1c77/β2a/α2δ and α1c77/β1/α2δ), expressed in HEK293 cells, were similarly suppressed by PF pulses. To examine whether Ca(2+) released by PF pulses triggered from different sub-cellular compartments (SR, ER, mitochondria) underlies the inhibitory effect of PF on the channel current, pharmacological agents and ionic substitutions were employed to probe this possibility. No significant difference in effectiveness of PF pulses to suppress ICa or IBa (used to inhibit CICR) was found between control cells and those exposed to U73122 and 2-APB (PLC and IP3R pathway modulators), thapsigargin and BAPTA (SERCA2a modulator), dinitrophenol, FCCP and Ru360 (mitochondrial inhibitors), l-NAME (NOS inhibitor signaling), cAMP and Pertussis toxin (Gi protein modulator). We concluded that the rapid and reversible modulation of the Ca(2+) channel by PF pulses is independent of intracellular release of Ca(2+) and Ca(2+) dependent inactivation of the channel and may represent direct mechanical regulatory effect on the channel protein in addition to previously reported Ca(2+)-release or entry dependent mechanism.
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Affiliation(s)
- Angelo O Rosa
- Cardiac Signaling Center, University of South Carolina, Charleston, SC 29425, USA
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14
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Mitochondrial free [Ca(2+)] dynamics measured with a novel low-Ca(2+) affinity aequorin probe. Biochem J 2012; 445:371-6. [PMID: 22671130 DOI: 10.1042/bj20120423] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Mitochondria have a very large capacity to accumulate Ca(2+) during cell stimulation driven by the mitochondrial membrane potential. Under these conditions, [Ca(2+)](M) (mitochondrial [Ca(2+)]) may well reach millimolar levels in a few seconds. Measuring the dynamics of [Ca(2+)](M) during prolonged stimulation has been previously precluded by the high Ca(2+) affinity of the probes available. We have now developed a mitochondrially targeted double-mutated form of the photoprotein aequorin which is able to measure [Ca(2+)] in the millimolar range for long periods of time without problems derived from aequorin consumption. We show in the present study that addition of Ca(2+) to permeabilized HeLa cells triggers an increase in [Ca(2+)](M) up to an steady state of approximately 2-3 mM in the absence of phosphate and 0.5-1 mM in the presence of phosphate, suggesting buffering or precipitation of calcium phosphate when the free [Ca(2+)] reaches 0.5-1 mM. Mitochondrial pH acidification partially re-dissolved these complexes. These millimolar [Ca(2+)](M) levels were stable for long periods of time provided the mitochondrial membrane potential was not collapsed. Silencing of the mitochondrial Ca(2+) uniporter largely reduced the rate of [Ca(2+)](M) increase, but the final steady-state [Ca(2+)](M) reached was similar. In intact cells, the new probe allows monitoring of agonist-induced increases of [Ca(2+)](M) without problems derived from aequorin consumption.
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15
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Zhou L, O'Rourke B. Cardiac mitochondrial network excitability: insights from computational analysis. Am J Physiol Heart Circ Physiol 2012; 302:H2178-89. [PMID: 22427517 DOI: 10.1152/ajpheart.01073.2011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In the heart, mitochondria form a regular lattice and function as a coordinated, nonlinear network to continuously produce ATP to meet the high-energy demand of the cardiomyocytes. Cardiac mitochondria also exhibit properties of an excitable system: electrical or chemical signals can spread within or among cells in the syncytium. The detailed mechanisms by which signals pass among individual elements (mitochondria) across the network are still not completely understood, although emerging studies suggest that network excitability might be mediated by the local diffusion and autocatalytic release of messenger molecules such as reactive oxygen species and/or Ca(2+). In this short review, we have attempted to described recent advances in the field of cardiac mitochondrial network excitability. Specifically, we have focused on how mitochondria communicate with each other through the diffusion and regeneration of messenger molecules to initiate and propagate waves or oscillations, as revealed by computational models of mitochondrial network.
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Affiliation(s)
- Lufang Zhou
- Division of Cardiovascular Disease, Department of Medicine, The University of Alabama at Birmingham, 35294, USA.
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16
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Cytosolic organelles shape calcium signals and exo–endocytotic responses of chromaffin cells. Cell Calcium 2012; 51:309-20. [DOI: 10.1016/j.ceca.2011.12.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 12/02/2011] [Accepted: 12/05/2011] [Indexed: 01/09/2023]
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17
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Mitochondria and chromaffin cell function. Pflugers Arch 2012; 464:33-41. [PMID: 22278417 DOI: 10.1007/s00424-012-1074-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 01/05/2012] [Accepted: 01/09/2012] [Indexed: 10/14/2022]
Abstract
Chromaffin cells are an excellent model for stimulus-secretion coupling. Ca(2+) entry through plasma membrane voltage-operated Ca(2+) channels (VOCC) is the trigger for secretion, but the intracellular organelles contribute subtle nuances to the Ca(2+) signal. The endoplasmic reticulum amplifies the cytosolic Ca(2+) ([Ca(2+)](C)) signal by Ca(2+)-induced Ca(2+) release (CICR) and helps generation of microdomains with high [Ca(2+)](C) (HCMD) at the subplasmalemmal region. These HCMD induce exocytosis of the docked secretory vesicles. Mitochondria close to VOCC take up large amounts of Ca(2+) from HCMD and stop progression of the Ca(2+) wave towards the cell core. On the other hand, the increase of [Ca(2+)] at the mitochondrial matrix stimulates respiration and tunes energy production to the increased needs of the exocytic activity. At the end of stimulation, [Ca(2+)](C) decreases rapidly and mitochondria release the Ca(2+) accumulated in the matrix through the Na(+)/Ca(2+) exchanger. VOCC, CICR sites and nearby mitochondria form functional triads that co-localize at the subplasmalemmal area, where secretory vesicles wait ready for exocytosis. These triads optimize stimulus-secretion coupling while avoiding propagation of the Ca(2+) signal to the cell core. Perturbation of their functioning in neurons may contribute to the genesis of excitotoxicity, ageing mental retardation and/or neurodegenerative disorders.
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18
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Yoo JO, Lee CH, Hwang BM, Kim WJ, Kim YM, Ha KS. Regulation of intracellular Ca2+ in the cytotoxic response to photodynamic therapy with a chlorin-based photosensitizer. J PORPHYR PHTHALOCYA 2012. [DOI: 10.1142/s1088424609001066] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We investigated regulation of intracellular Ca2+ induced by photodynamic therapy (PDT) with a new chlorin-based photosensitizer, DH-II-24, in human gastric adenocarcinoma cells. DH-II-24-mediated PDT induced necrotic cell death according to post-irradiation time, and produced intracellular reactive oxygen species (ROS) in an irradiation time-dependent manner. PDT also increased intracellular Ca2+ , and this Ca2+ elevation was largely inhibited by BAPTA-AM but not by EGTA. BAPTA-AM inhibited the ROS production by PDT, whereas NAC and Trolox had no effect on the PDT-induced Ca2+ response. In the presence of EGTA, pre-incubation with thapsigargin, Gly-Phe-β-naphthylamide or brefeldin A had no significant effect on the PDT-induced elevation in intracellular Ca2+ . However, ruthenium red affected the initial and late Ca2+ responses to PDT. Thus, DH-II-24-mediated PDT produces intracellular ROS via elevation in intracellular Ca2+ , contributed, at least in part, by mitochondria, which results in necrotic death of the human gastric adenocarcinoma cells.
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Affiliation(s)
- Je-Ok Yoo
- Department of Molecular and Cellular Biochemistry and Institute for Molecular Science and Fusion Technology, School of Medicine, Kangwon National University, Kangwon-do 200-701, Korea
| | - Chang-Hee Lee
- Department of Chemistry, College of Natural Science, Kangwon National University, Kangwon-do 200-701, Korea
| | - Byeong-Moon Hwang
- Department of Anesthesiology, School of Medicine Kangwon National University, Kangwon-do 200-701, Korea
| | - Woo Jin Kim
- Department of Internal Medicine, School of Medicine, Kangwon National University, Kangwon-do 200-701, Korea
| | - Young-Myeong Kim
- Department of Molecular and Cellular Biochemistry and Institute for Molecular Science and Fusion Technology, School of Medicine, Kangwon National University, Kangwon-do 200-701, Korea
| | - Kwon-Soo Ha
- Department of Molecular and Cellular Biochemistry and Institute for Molecular Science and Fusion Technology, School of Medicine, Kangwon National University, Kangwon-do 200-701, Korea
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19
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Coussee E, De Smet P, Bogaert E, Elens I, Van Damme P, Willems P, Koopman W, Van Den Bosch L, Callewaert G. G37R SOD1 mutant alters mitochondrial complex I activity, Ca(2+) uptake and ATP production. Cell Calcium 2011; 49:217-25. [PMID: 21388680 DOI: 10.1016/j.ceca.2011.02.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 02/10/2011] [Accepted: 02/14/2011] [Indexed: 02/06/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by selective death of motor neurons. Mutations in Cu/Zn superoxide dismutase-1 (SOD1) cause familial ALS but the molecular mechanisms whereby these mutations induce motor neuron death remain controversial. Here, we show that stable overexpression of mutant human SOD1 (G37R) - but not wild-type SOD1 (wt-SOD1) - in mouse neuroblastoma cells (N2a) results in morphological abnormalities of mitochondria accompanied by several dysfunctions. Activity of the oxidative phosphorylation complex I was significantly reduced in G37R cells and correlated with lower mitochondrial membrane potential and reduced levels of cytosolic ATP. Using targeted chimeric aequorin we further analyzed the consequences of mitochondrial dysfunction on cellular Ca(2+) handling. Mitochondrial Ca(2+) uptake, elicited by IP(3)-induced Ca(2+) release from endoplasmic reticulum (ER) was significantly reduced in G37R cells, while uptake induced by a brief Ca(2+) pulse was not affected in permeabilized cells. The decreased mitochondrial Ca(2+) uptake resulted in increased cytosolic Ca(2+) transients, whereas ER Ca(2+) load and resting cytosolic Ca(2+) levels were not affected. Together, these findings suggest that the mechanism linking mutant G37R SOD1 and ALS involves mitochondrial respiratory chain deficiency resulting in ATP loss and impairment of mitochondrial and cytosolic Ca(2+) homeostasis.
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Affiliation(s)
- Evelyne Coussee
- Research Group Neurodegeneration, Campus Kortrijk, K.U. Leuven, Belgium
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20
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Abstract
Peripheral taste receptor cells depend on distinct calcium signals to generate appropriate cellular responses that relay taste information to the central nervous system. Some taste cells have conventional chemical synapses and rely on calcium influx through voltage-gated calcium channels. Other taste cells lack these synapses and depend on calcium release from stores to formulate an output signal through a hemichannel. Despite the importance of calcium signaling in taste cells, little is known about how these signals are regulated. This review summarizes recent studies that have identified 2 calcium clearance mechanisms expressed in taste cells, including mitochondrial calcium uptake and sodium/calcium exchangers (NCXs). These studies identified a unique constitutive calcium influx that contributes to maintaining appropriate calcium homeostasis in taste cells and the role of the mitochondria and exchangers in this process. The additional role of NCXs in the regulation of evoked calcium responses is also discussed. Clearly, calcium signaling is a dynamic process in taste cells and appears to be more complex than has previously been appreciated.
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Affiliation(s)
- Kathryn F Medler
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA.
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21
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CARDIAC role of the mitochondrial Ca2+ transporters in the high-[K+](o) cardioprotection of rat hearts under ischemia and reperfusion: a mechano-energetic study. J Cardiovasc Pharmacol 2010; 54:213-22. [PMID: 19597370 DOI: 10.1097/fjc.0b013e3181b04ce3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED The role of mitochondrial transporters in the cardioprotection of rat hearts exposed to high [K+]-low [Ca2+]-cardioplegia (CPG) and ischemia and reperfusion (I/R) was studied through the mechano-energetic consequences of target drugs. The total heat rate (Ht) and the left intraventricular pressure (LVP) were simultaneously measured in isolated perfused hearts (30 degrees C and 1 Hz) inside a flow-calorimeter during 45 minutes of no-flow I and 45 minutes of R. After stabilization (C) they were pretreated with CPG and 100 microM 5-hydroxidecanoate (5HD, selective mKATP blocker) without and with 10 or 30 microM clonazepam (Clzp, mNCX inhibitor), 30 microM diazoxide (Dzx, selective mKATP opener), 1 microM Ru360 (selective Ca-uniporter blocker), and 0.2 microM cyclosporine-A, (mPTP inhibitor, before I and during R). Before I, 5-hydroxydecanoate in CPG increased the resting heat rate (17.83 +/- 3.55 mW/g) without changing the stunning. Clzp 30 microM + CPG + 5-hydroxydecanoate reduced the postischemic P with diastolic contracture and high Ht. Dzx protected C-hearts from stunning but increased it in CPG hearts with low economy (P/Ht) as well as Ru360. Cyclosporine-A did not modify the stunning of C or CPG ischemic hearts, suggesting that the mPTP was not opened. CONCLUSIONS Mitochondria have a precise role for determining cardioprotection or stunning in high-K+ cardioplegic rat hearts under I/R. Known protective drugs, such as Dzx and Ru360, which reduce the mitochondrial Ca2+-uptake, increased the stunning of CPG-rat hearts and reduced muscle economy, whereas 5-hydroxydecanoate and Clzp together increased the stunning by inducing mitochondrial Ca2+ overload.
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22
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Ruiz-Meana M, Fernandez-Sanz C, Garcia-Dorado D. The SR-mitochondria interaction: a new player in cardiac pathophysiology. Cardiovasc Res 2010; 88:30-9. [DOI: 10.1093/cvr/cvq225] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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23
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24
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Scullin CS, Partridge LD. Contributions of SERCA pump and ryanodine-sensitive stores to presynaptic residual Ca2+. Cell Calcium 2010; 47:326-38. [PMID: 20153896 DOI: 10.1016/j.ceca.2010.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 12/31/2009] [Accepted: 01/20/2010] [Indexed: 11/24/2022]
Abstract
The presynaptic Ca2+ signal, which triggers vesicle release, disperses to a broadly distributed residual [Ca2+] ([Ca2+](res)) that plays an important role in synaptic plasticity. We have previously reported a slowing in the decay timecourse of [Ca2+](res) during the second of paired pulses. In this study, we investigated the contributions of organelle and plasma membrane Ca2+ flux pathways to the reduction of effectiveness of [Ca2+](res) clearance during short-term plasticity in Schaffer collateral terminals in the CA1 field of the hippocampus. We show that the slowed decay timecourse is mainly the result of a transport-dependent Ca2+ clearance process; that presynaptic caffeine-sensitive Ca2+ stores are not functionally loaded in the unstimulated terminal, but that these stores can effectively take up Ca2+ even during high frequency trains of stimuli; and that a rate limiting step of sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) kinetics following the first pulse is responsible for a large portion of the observed slowing of [Ca2+](res) clearance during the second pulse. We were able to accurately fit our [Ca2+](res) data with a kinetic model based on these observations and this model predicted a reduction in availability of unbound SERCA during paired pulses, but no saturation of Ca2+ buffer in the endoplasmic reticulum.
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Affiliation(s)
- Chessa S Scullin
- Department of Neurosciences, University of New Mexico, School of Medicine, Albuquerque, NM 87131, USA
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25
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Chao D, Xia Y. Ionic storm in hypoxic/ischemic stress: can opioid receptors subside it? Prog Neurobiol 2009; 90:439-70. [PMID: 20036308 DOI: 10.1016/j.pneurobio.2009.12.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2009] [Revised: 09/10/2009] [Accepted: 12/17/2009] [Indexed: 12/17/2022]
Abstract
Neurons in the mammalian central nervous system are extremely vulnerable to oxygen deprivation and blood supply insufficiency. Indeed, hypoxic/ischemic stress triggers multiple pathophysiological changes in the brain, forming the basis of hypoxic/ischemic encephalopathy. One of the initial and crucial events induced by hypoxia/ischemia is the disruption of ionic homeostasis characterized by enhanced K(+) efflux and Na(+)-, Ca(2+)- and Cl(-)-influx, which causes neuronal injury or even death. Recent data from our laboratory and those of others have shown that activation of opioid receptors, particularly delta-opioid receptors (DOR), is neuroprotective against hypoxic/ischemic insult. This protective mechanism may be one of the key factors that determine neuronal survival under hypoxic/ischemic condition. An important aspect of the DOR-mediated neuroprotection is its action against hypoxic/ischemic disruption of ionic homeostasis. Specially, DOR signal inhibits Na(+) influx through the membrane and reduces the increase in intracellular Ca(2+), thus decreasing the excessive leakage of intracellular K(+). Such protection is dependent on a PKC-dependent and PKA-independent signaling pathway. Furthermore, our novel exploration shows that DOR attenuates hypoxic/ischemic disruption of ionic homeostasis through the inhibitory regulation of Na(+) channels. In this review, we will first update current information regarding the process and features of hypoxic/ischemic disruption of ionic homeostasis and then discuss the opioid-mediated regulation of ionic homeostasis, especially in hypoxic/ischemic condition, and the underlying mechanisms.
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Affiliation(s)
- Dongman Chao
- Yale University School of Medicine, Department of Pediatrics, New Haven, CT 06520, USA
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26
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Fahrner M, Muik M, Derler I, Schindl R, Fritsch R, Frischauf I, Romanin C. Mechanistic view on domains mediating STIM1-Orai coupling. Immunol Rev 2009; 231:99-112. [DOI: 10.1111/j.1600-065x.2009.00815.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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27
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Mann ZF, Duchen MR, Gale JE. Mitochondria modulate the spatio-temporal properties of intra- and intercellular Ca2+ signals in cochlear supporting cells. Cell Calcium 2009; 46:136-46. [PMID: 19631380 DOI: 10.1016/j.ceca.2009.06.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 06/12/2009] [Accepted: 06/28/2009] [Indexed: 10/20/2022]
Abstract
In the cochlea, cell damage triggers intercellular Ca2+ waves that propagate through the glial-like supporting cells that surround receptor hair cells. These Ca2+ waves are thought to convey information about sensory hair cell-damage to the surrounding supporting cells within the cochlear epithelium. Mitochondria are key regulators of cytoplasmic Ca2+ concentration ([Ca2+](cyt)), and yet little is known about their role during the propagation of such intercellular Ca2+ signalling. Using neonatal rat cochlear explants and fluorescence imaging techniques, we explore how mitochondria modulate supporting cell [Ca2+](cyt) signals that are triggered by ATP or by hair cell damage. ATP application (0.1-50 microM) caused a dose dependent increase in [Ca2+](cyt) which was accompanied by an increase in mitochondrial calcium. Blocking mitochondrial Ca2+ uptake by dissipating the mitochondrial membrane potential using CCCP and oligomycin or using Ru360, an inhibitor of the mitochondrial Ca2+ uniporter, enhanced the peak amplitude and duration of ATP-induced [Ca2+](cyt) transients. In the presence of Ru360, the mean propagation velocity, amplitude and extent of spread of damage-induced intercellular Ca2+ waves was significantly increased. Thus, mitochondria function as spatial Ca2+ buffers during agonist-evoked [Ca2+](cyt) signalling in cochlear supporting cells and play a significant role in regulating the spatio-temporal properties of intercellular Ca2+ waves.
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Affiliation(s)
- Zoë F Mann
- UCL Ear Institute, 332 Gray's Inn Road, London WC1X 8EE, UK; Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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28
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Michels G, Khan IF, Endres-Becker J, Rottlaender D, Herzig S, Ruhparwar A, Wahlers T, Hoppe UC. Regulation of the Human Cardiac Mitochondrial Ca
2+
Uptake by 2 Different Voltage-Gated Ca
2+
Channels. Circulation 2009; 119:2435-43. [DOI: 10.1161/circulationaha.108.835389] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background—
Impairment of intracellular Ca
2+
homeostasis and mitochondrial function has been implicated in the development of cardiomyopathy. Mitochondrial Ca
2+
uptake is thought to be mediated by the Ca
2+
uniporter (MCU) and a thus far speculative non-MCU pathway. However, the identity and properties of these pathways are a matter of intense debate, and possible functional alterations in diseased states have remained elusive.
Methods and Results—
By patch clamping the inner membrane of mitochondria from nonfailing and failing human hearts, we have identified 2 previously unknown Ca
2+
-selective channels, referred to as mCa1 and mCa2. Both channels are voltage dependent but differ significantly in gating parameters. Compared with mCa2 channels, mCa1 channels exhibit a higher single-channel amplitude, shorter openings, a lower open probability, and 3 to 5 subconductance states. Similar to the MCU, mCa1 is inhibited by 200 nmol/L ruthenium 360, whereas mCa2 is insensitive to 200 nmol/L ruthenium 360 and reduced only by very high concentrations (10 μmol/L). Both mitochondrial Ca
2+
channels are unaffected by blockers of other possibly Ca
2+
-conducting mitochondrial pores but were activated by spermine (1 mmol/L). Notably, activity of mCa1 and mCa2 channels is decreased in failing compared with nonfailing heart conditions, making them less effective for Ca
2+
uptake and likely Ca
2+
-induced metabolism.
Conclusions—
Thus, we conclude that the human mitochondrial Ca
2+
uptake is mediated by these 2 distinct Ca
2+
channels, which are functionally impaired in heart failure. Current properties reveal that the mCa1 channel underlies the human MCU and that the mCa2 channel is responsible for the ruthenium red–insensitive/low-sensitivity non-MCU–type mitochondrial Ca
2+
uptake.
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Affiliation(s)
- Guido Michels
- From the Department of Internal Medicine III (G.M., I.F.K., J.E.-B., D.R., U.C.H.), Center for Molecular Medicine (S.H., U.C.H.), Institute of Pharmacology (S.H.), and Department of Cardiothoracic Surgery (T.W.), University of Cologne, Cologne, and Department of Cardiac Surgery, University of Heidelberg, Heidelberg (A.R.), Germany
| | - Ismail F. Khan
- From the Department of Internal Medicine III (G.M., I.F.K., J.E.-B., D.R., U.C.H.), Center for Molecular Medicine (S.H., U.C.H.), Institute of Pharmacology (S.H.), and Department of Cardiothoracic Surgery (T.W.), University of Cologne, Cologne, and Department of Cardiac Surgery, University of Heidelberg, Heidelberg (A.R.), Germany
| | - Jeannette Endres-Becker
- From the Department of Internal Medicine III (G.M., I.F.K., J.E.-B., D.R., U.C.H.), Center for Molecular Medicine (S.H., U.C.H.), Institute of Pharmacology (S.H.), and Department of Cardiothoracic Surgery (T.W.), University of Cologne, Cologne, and Department of Cardiac Surgery, University of Heidelberg, Heidelberg (A.R.), Germany
| | - Dennis Rottlaender
- From the Department of Internal Medicine III (G.M., I.F.K., J.E.-B., D.R., U.C.H.), Center for Molecular Medicine (S.H., U.C.H.), Institute of Pharmacology (S.H.), and Department of Cardiothoracic Surgery (T.W.), University of Cologne, Cologne, and Department of Cardiac Surgery, University of Heidelberg, Heidelberg (A.R.), Germany
| | - Stefan Herzig
- From the Department of Internal Medicine III (G.M., I.F.K., J.E.-B., D.R., U.C.H.), Center for Molecular Medicine (S.H., U.C.H.), Institute of Pharmacology (S.H.), and Department of Cardiothoracic Surgery (T.W.), University of Cologne, Cologne, and Department of Cardiac Surgery, University of Heidelberg, Heidelberg (A.R.), Germany
| | - Arjang Ruhparwar
- From the Department of Internal Medicine III (G.M., I.F.K., J.E.-B., D.R., U.C.H.), Center for Molecular Medicine (S.H., U.C.H.), Institute of Pharmacology (S.H.), and Department of Cardiothoracic Surgery (T.W.), University of Cologne, Cologne, and Department of Cardiac Surgery, University of Heidelberg, Heidelberg (A.R.), Germany
| | - Thorsten Wahlers
- From the Department of Internal Medicine III (G.M., I.F.K., J.E.-B., D.R., U.C.H.), Center for Molecular Medicine (S.H., U.C.H.), Institute of Pharmacology (S.H.), and Department of Cardiothoracic Surgery (T.W.), University of Cologne, Cologne, and Department of Cardiac Surgery, University of Heidelberg, Heidelberg (A.R.), Germany
| | - Uta C. Hoppe
- From the Department of Internal Medicine III (G.M., I.F.K., J.E.-B., D.R., U.C.H.), Center for Molecular Medicine (S.H., U.C.H.), Institute of Pharmacology (S.H.), and Department of Cardiothoracic Surgery (T.W.), University of Cologne, Cologne, and Department of Cardiac Surgery, University of Heidelberg, Heidelberg (A.R.), Germany
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Walsh C, Barrow S, Voronina S, Chvanov M, Petersen OH, Tepikin A. Modulation of calcium signalling by mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1374-82. [PMID: 19344663 DOI: 10.1016/j.bbabio.2009.01.007] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2008] [Revised: 01/12/2009] [Accepted: 01/13/2009] [Indexed: 02/07/2023]
Abstract
In this review we will attempt to summarise the complex and sometimes contradictory effects that mitochondria have on different forms of calcium signalling. Mitochondria can influence Ca(2+) signalling indirectly by changing the concentration of ATP, NAD(P)H, pyruvate and reactive oxygen species - which in turn modulate components of the Ca(2+) signalling machinery i.e. buffering, release from internal stores, influx from the extracellular solution, uptake into cellular organelles and extrusion by plasma membrane Ca(2+) pumps. Mitochondria can directly influence the calcium concentration in the cytosol of the cell by importing Ca(2+) via the mitochondrial Ca(2+) uniporter or transporting Ca(2+) from the interior of the organelle into the cytosol by means of Na+/Ca(2+) or H+/Ca(2+) exchangers. Considerable progress in understanding the relationship between Ca(2+) signalling cascades and mitochondrial physiology has been accumulated over the last few years due to the development of more advanced optical techniques and electrophysiological approaches.
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Affiliation(s)
- Ciara Walsh
- Department of Physiology, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool L69 3BX, UK
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30
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Demaurex N, Poburko D, Frieden M. Regulation of plasma membrane calcium fluxes by mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1383-94. [PMID: 19161976 DOI: 10.1016/j.bbabio.2008.12.012] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 12/21/2008] [Accepted: 12/29/2008] [Indexed: 11/27/2022]
Abstract
The role of mitochondria in cell signaling is becoming increasingly apparent, to an extent that the signaling role of mitochondria appears to have stolen the spotlight from their primary function as energy producers. In this chapter, we will review the ionic basis of calcium handling by mitochondria and discuss the mechanisms that these organelles use to regulate the activity of plasma membrane calcium channels and transporters.
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Affiliation(s)
- Nicolas Demaurex
- Department of Cell Physiology and Metabolism, University of Geneva, 1, rue Michel-Servet, CH-1211 Geneva 4, Switzerland
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31
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Alonso MT, Manjarrés IM, García-Sancho J. Modulation of calcium signalling by intracellular organelles seen with targeted aequorins. Acta Physiol (Oxf) 2009; 195:37-49. [PMID: 18983457 DOI: 10.1111/j.1748-1716.2008.01920.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cytosolic Ca(2+) signals that trigger cell responses occur either as localized domains of high Ca(2+) concentration or as propagating Ca(2+) waves. Cytoplasmic organelles, taking up or releasing Ca(2+) to the cytosol, shape the cytosolic signals. On the other hand, Ca(2+) concentration inside organelles is also important in physiology and pathophysiology. Comprehensive study of these matters requires to measure [Ca(2+)] inside organelles and at the relevant cytosolic domains. Aequorins, the best-known chemiluminescent Ca(2+) probes, are excellent for this end as they do not require stressing illumination, have a large dynamic range and a sharp Ca(2+)-dependence, can be targeted to the appropriate location and engineered to have the proper Ca(2+) affinity. Using this methodology, we have evidenced the existence in chromaffin cells of functional units composed by three closely interrelated elements: (1) plasma membrane Ca(2+) channels, (2) subplasmalemmal endoplasmic reticulum and (3) mitochondria. These Ca(2+)-signalling triads optimize Ca(2+) microdomains for secretion and prevent propagation of the Ca(2+) wave towards the cell core. Oscillatory cytosolic Ca(2+) signals originate also oscillations of mitochondrial Ca(2+) in several cell types. The nuclear envelope slows down the propagation of the Ca(2+) wave to the nucleus and filters high frequencies. On the other hand, inositol-trisphosphate may produce direct release of Ca(2+) to the nucleoplasm in GH(3) pituitary cells, thus providing mechanisms for selective nuclear signalling. Aequorins emitting at different wavelengths, prepared by fusion either with green or red fluorescent protein, permit simultaneous and independent monitorization of the Ca(2+) signals in different subcellular domains within the same cell.
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Affiliation(s)
- M T Alonso
- Instituto de Biología y Genética Molecular, Universidad de Valladolid y Consejo Superior de Investigaciones Científicas, Valladolid, Spain
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Hacker K, Medler KF. Mitochondrial calcium buffering contributes to the maintenance of Basal calcium levels in mouse taste cells. J Neurophysiol 2008; 100:2177-91. [PMID: 18684902 DOI: 10.1152/jn.90534.2008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Taste stimuli are detected by taste receptor cells present in the oral cavity using diverse signaling pathways. Some taste stimuli are detected by G protein-coupled receptors (GPCRs) that cause calcium release from intracellular stores, whereas other stimuli depolarize taste cells to cause calcium influx through voltage-gated calcium channels (VGCCs). Although taste cells use two distinct mechanisms to transmit taste signals, increases in cytosolic calcium are critical for normal responses in both pathways. This creates a need to tightly control intracellular calcium levels in all transducing taste cells. To date, however, the mechanisms used by taste cells to regulate cytosolic calcium levels have not been identified. Studies in other cell types have shown that mitochondria can be important calcium buffers, even during small changes in calcium loads. In this study, we used calcium imaging to characterize the role of mitochondria in buffering calcium levels in taste cells. We discovered that mitochondria make important contributions to the maintenance of resting calcium levels in taste cells by routinely buffering a constitutive calcium influx across the plasma membrane. This is unusual because in other cell types, mitochondrial calcium buffering primarily affects large evoked calcium responses. We also found that the amount of calcium that is buffered by mitochondria varies with the signaling pathways used by the taste cells. A transient receptor potential (TRP) channel, likely TRPV1 or a taste variant of TRPV1, contributes to the constitutive calcium influx.
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Affiliation(s)
- Kyle Hacker
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
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Abstract
Mitochondria couple cellular metabolic state with Ca(2+) transport processes. They therefore control not only their own intra-organelle [Ca(2+)], but they also influence the entire cellular network of cellular Ca(2+) signaling, including the endoplasmic reticulum, the plasma membrane, and the nucleus. Through the detailed study of mitochondrial roles in Ca(2+) signaling, a remarkable picture of inter-organelle communication has emerged. We here review the ways in which this system provides integrity and flexibility for the cell to cope with the countless demands throughout its life cycle and discuss briefly the mechanisms through which it can also drive cell death.
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Affiliation(s)
- György Szabadkai
- Department of Physiology, Mitochondrial Biology Group, University College London, London, United Kingdom.
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García-Sancho J, Verkhratsky A. Cytoplasmic organelles determine complexity and specificity of calcium signalling in adrenal chromaffin cells. Acta Physiol (Oxf) 2008; 192:263-71. [PMID: 18021325 DOI: 10.1111/j.1748-1716.2007.01812.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Complex and coordinated fluctuations of intracellular free Ca2+ concentration ([Ca2+]c) regulate secretion of adrenaline from chromaffin cells. The physiologically relevant intracellular Ca2+ signals occur either as localized microdomains of high Ca2+ concentrations or as propagating Ca2+ waves, which give rise to global Ca2+ elevations. Intracellular organelles, the endoplasmic reticulum (ER), mitochondria and nuclear envelope, are endowed with powerful Ca2+ transport systems. Calcium uptake and Ca2+ release from these organelles determine the spatial and temporal parameters of Ca2+ signalling events. Furthermore, the ER and mitochondria form close relations with the sites of plasmalemmal Ca2+ entry, creating 'Ca2+ signalling triads' which act as elementary operational units, which regulate exocytosis. Ca2+ ions accumulating in the ER and mitochondria integrate exocytotic activity with energy production and protein synthesis.
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Affiliation(s)
- J García-Sancho
- Departamento de Fisiología, Facultad de Medicina, Instituto de Biología y Genética Molecular, Universidad de Valladolid y Consejo Superior de Investigaciones Científicas, Valladolid, Spain.
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Javadov S, Karmazyn M. Mitochondrial permeability transition pore opening as an endpoint to initiate cell death and as a putative target for cardioprotection. Cell Physiol Biochem 2007; 20:1-22. [PMID: 17595511 DOI: 10.1159/000103747] [Citation(s) in RCA: 221] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2007] [Indexed: 01/19/2023] Open
Abstract
In recent years, mitochondria have been recognized as regulators of cell death via both apoptosis and necrosis in addition to their essential role for cell survival. Cellular dysfunctions induced by intra- or extracellular insults converge on mitochondria and induce a sudden increase in permeability of the inner mitochondrial membrane, the so-called mitochondrial permeability transition. The mitochondrial permeability transition is caused by the opening of permeability transition pores (PTP) in the inner mitochondrial membrane with subsequent loss of ionic homeostasis, matrix swelling and outer membrane rupture. The detailed molecular mechanisms underlying the PTP-induced cellular dysfunction during cardiac pathology such as ischemia/reperfusion or post-infarction remodeling remain to be elucidated. However, a growing body of evidence supports the concept that pharmacological inhibition of the PTP is an effective and promising strategy for the protection of the heart against ischemia/reperfusion injury and for attenuation of the remodeling process which contributes to heart failure. This review summarizes and discusses current data on i) the structure and function of the PTP, ii) possible mechanisms and consequences of PTP opening and iii) the inhibition of PTP opening as a therapeutic approach for treatment of heart disease.
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Affiliation(s)
- Sabzali Javadov
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
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36
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Vay L, Hernández-Sanmiguel E, Santo-Domingo J, Lobatón CD, Moreno A, Montero M, Alvarez J. Modulation of Ca(2+) release and Ca(2+) oscillations in HeLa cells and fibroblasts by mitochondrial Ca(2+) uniporter stimulation. J Physiol 2007; 580:39-49. [PMID: 17234694 PMCID: PMC2075421 DOI: 10.1113/jphysiol.2006.126391] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The recent availability of activators of the mitochondrial Ca(2+) uniporter allows direct testing of the influence of mitochondrial Ca(2+) uptake on the overall Ca(2+) homeostasis of the cell. We show here that activation of mitochondrial Ca(2+) uptake by 4,4',4''-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT) or kaempferol stimulates histamine-induced Ca(2+) release from the endoplasmic reticulum (ER) and that this effect is enhanced if the mitochondrial Na(+)-Ca(2+) exchanger is simultaneously inhibited with CGP37157. This suggests that both Ca(2+) uptake and release from mitochondria control the ability of local Ca(2+) microdomains to produce feedback inhibition of inositol 1,4,5-trisphosphate receptors (InsP(3)Rs). In addition, the ability of mitochondria to control Ca(2+) release from the ER allows them to modulate cytosolic Ca(2+) oscillations. In histamine stimulated HeLa cells and human fibroblasts, both PPT and kaempferol initially stimulated and later inhibited oscillations, although kaempferol usually induced a more prolonged period of stimulation. Both compounds were also able to induce the generation of Ca(2+) oscillations in previously silent fibroblasts. Our data suggest that cytosolic Ca(2+) oscillations are exquisitely sensitive to the rates of mitochondrial Ca(2+) uptake and release, which precisely control the size of the local Ca(2+) microdomains around InsP(3)Rs and thus the ability to produce feedback activation or inhibition of Ca(2+) release.
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Affiliation(s)
- Laura Vay
- Instituto de Biología y Genética Molecular (IBGM), Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Ramón y Cajal, 7, E-47005 Valladolid, Spain
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Kubota M, Kasahara T, Nakamura T, Ishiwata M, Miyauchi T, Kato T. Abnormal Ca2+ dynamics in transgenic mice with neuron-specific mitochondrial DNA defects. J Neurosci 2006; 26:12314-24. [PMID: 17122057 PMCID: PMC6675445 DOI: 10.1523/jneurosci.3933-06.2006] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2006] [Revised: 10/12/2006] [Accepted: 10/15/2006] [Indexed: 11/21/2022] Open
Abstract
Maintenance of mitochondrial DNA (mtDNA) depends on nuclear-encoded proteins such as mtDNA polymerase (POLG), whose mutations are involved in the diseases caused by mtDNA defects including mutation and deletion. The defects in mtDNA and in intracellular Ca2+ ([Ca2+]i) homeostasis have been reported in bipolar disorder (BD). To understand the relevance of the mtDNA defects to BD, we studied transgenic (Tg) mice in which mutant POLG (mutPOLG) was expressed specifically in neurons. mtDNA defects were accumulated in the brains of mutPOLG Tg mice in an age-dependent manner and the mutant mice showed BD-like behavior. However, the molecular and cellular basis for the abnormalities has not been clarified. In this study, we investigated Ca2+ regulation by isolated mitochondria and [Ca2+]i dynamics in the neurons of mutPOLG Tg mice. Mitochondria from the mutant mice sequestered Ca2+ more rapidly, whereas Ca2+ retention capacity and membrane potential, a driving force of Ca2+ uptake, of mitochondria were unaffected. To elucidate the molecular mechanism of the altered Ca2+ uptake, we performed DNA microarray analysis and found that the expression of cyclophilin D (CyP-D), a component of the permeability transition pore, was downregulated in the brains of mutPOLG Tg mice. Cyclosporin A, an inhibitor of CyP-D, mimicked the enhanced Ca2+ uptake in mutant mice. Furthermore, G-protein-coupled receptor-mediated [Ca2+]i increase was attenuated in hippocampal neurons of the mutant mice. These findings suggest that mtDNA defects lead to enhancement of Ca2+ uptake rate via CyP-D downregulation and alter [Ca2+]i dynamics, which may be involved in the pathogenesis of BD.
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Affiliation(s)
- Mie Kubota
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan, and
| | - Takaoki Kasahara
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan, and
| | - Takeshi Nakamura
- Department of Physiology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Mizuho Ishiwata
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan, and
| | - Taeko Miyauchi
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan, and
| | - Tadafumi Kato
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan, and
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Alonso MT, Villalobos C, Chamero P, Alvarez J, García-Sancho J. Calcium microdomains in mitochondria and nucleus. Cell Calcium 2006; 40:513-25. [PMID: 17067669 DOI: 10.1016/j.ceca.2006.08.013] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Accepted: 08/23/2006] [Indexed: 10/24/2022]
Abstract
Endomembranes modify the progression of the cytosolic Ca(2+) wave and contribute to generate Ca(2+) microdomains, both in the cytosol and inside the own organella. The concentration of Ca(2+) in the cytosol ([Ca(2+)](C)), the mitochondria ([Ca(2+)](M)) and the nucleus ([Ca(2+)](N)) are similar at rest, but may become very different during cell activation. Mitochondria avidly take up Ca(2+) from the high [Ca(2+)](C) microdomains generated during cell activation near Ca(2+) channels of the plasma membrane and/or the endomembranes and prevent propagation of the high Ca(2+) signal to the bulk cytosol. This shaping of [Ca(2+)](C) signaling is essential for independent regulation of compartmentalized cell functions. On the other hand, a high [Ca(2+)](M) signal is generated selectively in the mitochondria close to the active areas, which tunes up respiration to the increased local needs. The progression of the [Ca(2+)](C) signal to the nucleus may be dampened by mitochondria, the nuclear envelope or higher buffering power inside the nucleoplasm. On the other hand, selective [Ca(2+)](N) signals could be generated by direct release of stored Ca(2+) into the nucleoplasm. Ca(2+) release could even be restricted to subnuclear domains. Putative Ca(2+) stores include the nuclear envelope, their invaginations inside the nucleoplasm (nucleoplasmic reticulum) and nuclear microvesicles. Inositol trisphosphate, cyclic ADP-ribose and nicotinic acid adenine dinucleotide phosphate have all been reported to produce release of Ca(2+) into the nucleoplasm, but contribution of these mechanisms under physiological conditions is still uncertain.
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Affiliation(s)
- María Teresa Alonso
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés s/n, Valladolid, Spain
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39
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García AG, García-De-Diego AM, Gandía L, Borges R, García-Sancho J. Calcium Signaling and Exocytosis in Adrenal Chromaffin Cells. Physiol Rev 2006; 86:1093-131. [PMID: 17015485 DOI: 10.1152/physrev.00039.2005] [Citation(s) in RCA: 259] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
At a given cytosolic domain of a chromaffin cell, the rate and amplitude of the Ca2+concentration ([Ca2+]c) depends on at least four efficient regulatory systems: 1) plasmalemmal calcium channels, 2) endoplasmic reticulum, 3) mitochondria, and 4) chromaffin vesicles. Different mammalian species express different levels of the L, N, P/Q, and R subtypes of high-voltage-activated calcium channels; in bovine and humans, P/Q channels predominate, whereas in felines and murine species, L-type channels predominate. The calcium channels in chromaffin cells are regulated by G proteins coupled to purinergic and opiate receptors, as well as by voltage and the local changes of [Ca2+]c. Chromaffin cells have been particularly useful in studying calcium channel current autoregulation by materials coreleased with catecholamines, such as ATP and opiates. Depending on the preparation (cultured cells, adrenal slices) and the stimulation pattern (action potentials, depolarizing pulses, high K+, acetylcholine), the role of each calcium channel in controlling catecholamine release can change drastically. Targeted aequorin and confocal microscopy shows that Ca2+entry through calcium channels can refill the endoplasmic reticulum (ER) to nearly millimolar concentrations, and causes the release of Ca2+(CICR). Depending on its degree of filling, the ER may act as a sink or source of Ca2+that modulates catecholamine release. Targeted aequorins with different Ca2+affinities show that mitochondria undergo surprisingly rapid millimolar Ca2+transients, upon stimulation of chromaffin cells with ACh, high K+, or caffeine. Physiological stimuli generate [Ca2+]cmicrodomains in which the local subplasmalemmal [Ca2+]crises abruptly from 0.1 to ∼50 μM, triggering CICR, mitochondrial Ca2+uptake, and exocytosis at nearby secretory active sites. The fact that protonophores abolish mitochondrial Ca2+uptake, and increase catecholamine release three- to fivefold, support the earlier observation. This increase is probably due to acceleration of vesicle transport from a reserve pool to a ready-release vesicle pool; this transport might be controlled by Ca2+redistribution to the cytoskeleton, through CICR, and/or mitochondrial Ca2+release. We propose that chromaffin cells have developed functional triads that are formed by calcium channels, the ER, and the mitochondria and locally control the [Ca2+]cthat regulate the early and late steps of exocytosis.
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Affiliation(s)
- Antonio G García
- Instituto Teófilo Hernando, Departamento de Farmacología y Terapéutica, and Servicio de Farmacología Clínica e Instituto Universitario de Investigación Gerontológica y Metabólica, Hospital Universitario de la Princesa, Madrid, Spain.
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40
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Kuba M, Higure Y, Susaki H, Hayato R, Kuba K. Bidirectional Ca2+ coupling of mitochondria with the endoplasmic reticulum and regulation of multimodal Ca2+ entries in rat brown adipocytes. Am J Physiol Cell Physiol 2006; 292:C896-908. [PMID: 16987997 DOI: 10.1152/ajpcell.00649.2005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
How the endoplasmic reticulum (ER) and mitochondria communicate with each other and how they regulate plasmalemmal Ca(2+) entry were studied in cultured rat brown adipocytes. Cytoplasmic Ca(2+) or Mg(2+) and mitochondrial membrane potential were measured by fluorometry. The sustained component of rises in cytoplasmic Ca(2+) concentration ([Ca(2+)](i)) produced by thapsigargin was abolished by removing extracellular Ca(2+), depressed by depleting extracellular Na(+), and enhanced by raising extracellular pH. FCCP, dinitrophenol, and rotenone caused bi- or triphasic rises in [Ca(2+)](i), in which the first phase was accompanied by mitochondrial depolarization. The FCCP-induced first phase was partially inhibited by oligomycin but not by ruthenium red, cyclosporine A, U-73122, a Ca(2+)-free EGTA solution, and an Na(+)-free solution. The FCCP-induced second phase paralleling mitochondrial repolarization was partially blocked by removing extracellular Ca(2+) and fully blocked by oligomycin but not by thapsigargin or an Na(+)-deficient solution, was accompanied by a rise in cytoplasmic Mg(2+) concentration, and was summated with a high pH-induced rise in [Ca(2+)](i), whereas the extracellular Ca(2+)-independent component was blocked by U-73122 and cyclopiazonic acid. The FCCP-induced third phase was blocked by removing Ca(2+) but not by thapsigargin, depressed by decreasing Na(+), and enhanced by raising pH. Cyclopiazonic acid-evoked rises in [Ca(2+)](i) in a Ca(2+)-free solution were depressed after FCCP actions. Thus mitochondrial uncoupling causes Ca(2+) release, activating Ca(2+) release from the ER and store-operated Ca(2+) entry, and directly elicits a novel plasmalemmal Ca(2+) entry, whereas Ca(2+) release from the ER activates Ca(2+) accumulation in, or release from, mitochondria, indicating bidirectional mitochondria-ER couplings in rat brown adipocytes.
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Affiliation(s)
- Masako Kuba
- Laboratory of Anatomy and Physiology, School of Nutritional Sciences, Nagoya Univ. of Arts and Sciences, 57 Takenoyama, Iwasaki-cho, Nissin, Aichi 470-0196, Japan.
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41
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Hernández-SanMiguel E, Vay L, Santo-Domingo J, Lobatón CD, Moreno A, Montero M, Alvarez J. The mitochondrial Na+/Ca2+ exchanger plays a key role in the control of cytosolic Ca2+ oscillations. Cell Calcium 2006; 40:53-61. [PMID: 16720043 DOI: 10.1016/j.ceca.2006.03.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Revised: 03/06/2006] [Accepted: 03/23/2006] [Indexed: 01/13/2023]
Abstract
There is increasing evidence that mitochondria play an important role in the control of cytosolic Ca2+ signaling. We show here that the main mitochondrial Ca2+-exit pathway, the mitochondrial Na+/Ca2+ exchanger, controls the pattern of cytosolic Ca2+ oscillations in non-excitable cells. In HeLa cells, the inhibitor of the mitochondrial Na+/Ca2+ exchanger CGP37157 changed the pattern of the oscillations induced by histamine from a high-frequency irregular one to a lower frequency baseline spike type, surprisingly with little changes in the average Ca2+ values of a large cell population. In human fibroblasts, CGP37157 increased the frequency of the baseline oscillations in cells having spontaneous activity and induced the generation of oscillations in cells without spontaneous activity. This effect was dose-dependent, disappeared when the inhibitor was washed out and was not mimicked by mitochondrial depolarization. CGP37157 increased mitochondrial [Ca2+] and ATP production in histamine-stimulated HeLa cells, but the effect on ATP production was only transient. CGP37157 also activated histamine-induced Ca2+ release from the endoplasmic reticulum and increased the size of the cytosolic Ca2+ peak induced by histamine in HeLa cells. Our results suggest that the mitochondrial Na+/Ca2+ exchanger directly modulates inositol 1,4,5-trisphosphate-induced Ca2+ release and in that way controls cytosolic Ca2+ oscillations.
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Affiliation(s)
- Esther Hernández-SanMiguel
- Instituto de Biología y Genética Molecular, Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Universidad de Valladolid and Consejo Superior de Investigaciones Científicas, Ramón y Cajal, 7, E-47005 Valladolid, Spain
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42
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Conde SV, Caceres AI, Vicario I, Rocher A, Obeso A, Gonzalez C. An overview on the homeostasis of Ca2+ in chemoreceptor cells of the rabbit and rat carotid bodies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 580:215-22; discussion 351-9. [PMID: 16683722 DOI: 10.1007/0-387-31311-7_33] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Affiliation(s)
- S V Conde
- Departamento de Bioquimica y Biologia Moleculary Fisiología/IBGMFacultad de Medicina. Universidad de Valladolid/CSIC, 47005Valladolid, Spain
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43
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Camello-Almaraz C, Gomez-Pinilla PJ, Pozo MJ, Camello PJ. Mitochondrial reactive oxygen species and Ca2+ signaling. Am J Physiol Cell Physiol 2006; 291:C1082-8. [PMID: 16760264 DOI: 10.1152/ajpcell.00217.2006] [Citation(s) in RCA: 241] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondria are an important source of reactive oxygen species (ROS) formed as a side product of oxidative phosphorylation. The main sites of oxidant production are complex I and complex III, where electrons flowing from reduced substrates are occasionally transferred to oxygen to form superoxide anion and derived products. These highly reactive compounds have a well-known role in pathological states and in some cellular responses. However, although their link with Ca(2+) is well studied in cell death, it has been hardly investigated in normal cytosolic calcium concentration ([Ca(2+)](i)) signals. Several Ca(2+) transport systems are modulated by oxidation. Oxidation increases the activity of inositol 1,4,5-trisphosphate and ryanodine receptors, the main channels releasing Ca(2+) from intracellular stores in response to cellular stimulation. On the other hand, mitochondria are known to control [Ca(2+)](i) signals by Ca(2+) uptake and release during cytosolic calcium mobilization, specially in mitochondria situated close to Ca(2+) release channels. Mitochondrial inhibitors modify calcium signals in numerous cell types, including oscillations evoked by physiological stimulus. Although these inhibitors reduce mitochondrial Ca(2+) uptake, they also impair ROS production in several systems. In keeping with this effect, recent reports show that antioxidants or oxidant scavengers also inhibit physiological calcium signals. Furthermore, there is evidence that mitochondria generate ROS in response to cell stimulation, an effect suppressed by mitochondrial inhibitors that simultaneously block [Ca(2+)](i) signals. Together, the data reviewed here indicate that Ca(2+)-mobilizing stimulus generates mitochondrial ROS, which, in turn, facilitate [Ca(2+)](i) signals, a new aspect in the biology of mitochondria. Finally, the potential implications for biological modeling are discussed.
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44
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Zhang BX, Ma X, Zhang W, Yeh CK, Lin A, Luo J, Sprague EA, Swerdlow RH, Katz MS. Polyunsaturated fatty acids mobilize intracellular Ca2+in NT2 human teratocarcinoma cells by causing release of Ca2+from mitochondria. Am J Physiol Cell Physiol 2006; 290:C1321-33. [PMID: 16601147 DOI: 10.1152/ajpcell.00335.2005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In a variety of disorders, overaccumulation of lipid in nonadipose tissues, including the heart, skeletal muscle, kidney, and liver, is associated with deterioration of normal organ function, and is accompanied by excessive plasma and cellular levels of free fatty acids (FA). Increased concentrations of FA may lead to defects in mitochondrial function found in diverse diseases. One of the most important regulators of mitochondrial function is mitochondrial Ca2+([Ca2+]m), which fluctuates in coordination with intracellular Ca2+([Ca2+]i). Polyunsaturated FA (PUFA) have been shown to cause [Ca2+]imobilization albeit by unknown mechanisms. We have found that PUFA but not monounsaturated or saturated FA cause [Ca2+]imobilization in NT2 human teratocarcinoma cells. Unlike the [Ca2+]iresponse to the muscarinic G protein-coupled receptor agonist carbachol, PUFA-mediated [Ca2+]imobilization in NT2 cells is independent of phospholipase C and inositol-1,4,5-trisphospate (IP3) receptor activation, as well as IP3-sensitive internal Ca2+stores. Furthermore, PUFA-mediated [Ca2+]imobilization is inhibited by the mitochondria uncoupler carboxyl cyanide m-chlorophenylhydrozone. Direct measurements of [Ca2+]mwith X-rhod-1 and45Ca2+indicate that PUFA induce Ca2+efflux from mitochondria. Further studies show that ruthenium red, an inhibitor of the mitochondrial Ca2+uniporter, blocks PUFA-induced Ca2+efflux from mitochondria, whereas inhibitors of the mitochondrial permeability transition pore cyclosporin A and bongkrekic acid have no effect. Thus PUFA-gated Ca2+release from mitochondria, possibly via the Ca2+uniporter, appears to be the underlying mechanism for PUFA-induced [Ca2+]imobilization in NT2 cells.
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Affiliation(s)
- Bin-Xian Zhang
- Geriatric Research, Education and Clinical Center (182), South Texas Veterans Health Care System, Audie L. Murphy Division, 7400 Merton Minter Blvd., San Antonio, TX 78229, USA.
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45
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Nikolaeva MA, Mukherjee B, Stys PK. Na+-dependent sources of intra-axonal Ca2+ release in rat optic nerve during in vitro chemical ischemia. J Neurosci 2006; 25:9960-7. [PMID: 16251444 PMCID: PMC6725557 DOI: 10.1523/jneurosci.2003-05.2005] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The contribution of intracellular stores to axonal Ca2+ overload during chemical ischemia in vitro was examined by confocal microscopy. Ca2+ accumulation was measured by fluo-4 dextran (low-affinity dye, KD approximately 4 microM) or by Oregon Green 488 BAPTA-1 dextran (highaffinity dye, KD approximately 450 nM). Axonal Na+ was measured using CoroNa Green. Ischemia in CSF containing 2 mM Ca2+ caused an approximately 3.5-fold increase in fluo-4 emission after 30 min, indicating a large axonal Ca2+ rise well into the micromolar range. Axonal Na+ accumulation was enhanced by veratridine and reduced, but not abolished, by TTX. Ischemia in Ca2+-free (plus BAPTA) perfusate resulted in a smaller but consistent Ca2+ increase monitored by Oregon Green 488 BAPTA-1, indicating release from intracellular sources. This release was eliminated in large part when Na+ influx was reduced by replacement with N-methyl-D-glucamine (NMDG+; even in depolarizing high K+ perfusate), Li+, or by the application of TTX and significantly increased by veratridine. Intracellular release also was reduced significantly by neomycin or 1-(6-[(17beta-methoxyestra-1,3,5 [10]-trien-17-yl) amino] hexyl)-1H-pyrrole-2,5-dione (U73122 [GenBank]) (phospholipase C inhibitors), heparin [inositol trisphosphate (IP3) receptor blocker], or 7-chloro-5-(2-chlorophenyl)-1,5-dihydro-4,1-benzothiazepin-2(3H)-one (CGP37157; mitochondrial Na+/Ca2+ exchange inhibitor) as well as ryanodine. Combining CGP37157 with U73122 [GenBank] or heparin decreased the response more than either agent alone and significantly improved electrophysiological recovery. Our conclusion is that intra-axonal Ca2+ release during ischemia in rat optic nerve is mainly dependent on Na+ influx. This Na+ accumulation stimulates three distinct intra-axonal sources of Ca2+: (1) the mitochondrial Na+/Ca2+ exchanger driven in the Na+ import/Ca2+ export mode, (2) positive modulation of ryanodine receptors, and (3) promotion of IP3 generation by phospholipase C.
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Affiliation(s)
- Maria A Nikolaeva
- Division of Neuroscience, Ottawa Health Research Institute, University of Ottawa, Ottawa, Ontario, K1Y 4K9, Canada
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Abstract
The integrity of mitochondrial function is fundamental to cell life. It follows that disturbances of mitochondrial function will lead to disruption of cell function, expressed as disease or even death. In this review, I consider recent developments in our knowledge of basic aspects of mitochondrial biology as an essential step in developing our understanding of the contributions of mitochondria to disease. The identification of novel mechanisms that govern mitochondrial biogenesis and replication, and the delicately poised signalling pathways that coordinate the mitochondrial and nuclear genomes are discussed. As fluorescence imaging has made the study of mitochondrial function within cells accessible, the application of that technology to the exploration of mitochondrial bioenergetics is reviewed. Mitochondrial calcium uptake plays a major role in influencing cell signalling and in the regulation of mitochondrial function, while excessive mitochondrial calcium accumulation has been extensively implicated in disease. Mitochondria are major producers of free radical species, possibly also of nitric oxide, and are also major targets of oxidative damage. Mechanisms of mitochondrial radical generation, targets of oxidative injury and the potential role of uncoupling proteins as regulators of radical generation are discussed. The role of mitochondria in apoptotic and necrotic cell death is seminal and is briefly reviewed. This background leads to a discussion of ways in which these processes combine to cause illness in the neurodegenerative diseases and in cardiac reperfusion injury. The demands of mitochondria and their complex integration into cell biology extends far beyond the provision of ATP, prompting a radical change in our perception of mitochondria and placing these organelles centre stage in many aspects of cell biology and medicine.
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Affiliation(s)
- Michael R Duchen
- Department of Physiology and Mitochondrial Biology Group, University College London, Gower Street, London WC1E 6BT, UK.
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Abstract
Mitochondria are increasingly ascribed central roles in vital cell signalling cascades. These organelles are now recognised as initiators and transducers of a range of cell signals, including those central to activation and amplification of apoptotic cell death. Moreover, as the main source of cellular ATP, mitochondria must be responsive to fluctuating energy demands of the cell. As local and global fluctuations in calcium concentration are ubiquitous in eukaryotic cells and are the common factor in a dizzying array of intra- and inter-cellular signalling cascades, the relationships between mitochondrial function and calcium transients is currently a subject of intense scrutiny. It is clear that mitochondria not only act as local calcium buffers, thus shaping spatiotemporal aspects of cytosolic calcium signals, but that they also respond to calcium uptake by upregulating the tricarboxylic acid cycle, thus reacting metabolically to local signalling. In this chapter we review current knowledge of mechanisms of mitochondrial calcium uptake and release and discuss the consequences of mitochondrial calcium handling for cell function, particularly in conjunction with mitochondrial oxidative stress.
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Affiliation(s)
- Jake Jacobson
- Department of Physiology, University College London, London, UK.
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Saotome M, Katoh H, Satoh H, Nagasaka S, Yoshihara S, Terada H, Hayashi H. Mitochondrial membrane potential modulates regulation of mitochondrial Ca2+ in rat ventricular myocytes. Am J Physiol Heart Circ Physiol 2004; 288:H1820-8. [PMID: 15563537 DOI: 10.1152/ajpheart.00589.2004] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although recent studies focused on the contribution of mitochondrial Ca2+ to the mechanisms of ischemia-reperfusion injury, the regulation of mitochondrial Ca2+ under pathophysiological conditions remains largely unclear. By using saponin-permeabilized rat myocytes, we measured mitochondrial membrane potential (DeltaPsi(m)) and mitochondrial Ca2+ concentration ([Ca2+](m)) at the physiological range of cytosolic Ca2+ concentration ([Ca2+](c); 300 nM) and investigated the regulation of [Ca2+](m) during both normal and dissipated DeltaPsi(m). When DeltaPsi(m) was partially depolarized by carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP, 0.01-0.1 microM), there were dose-dependent decreases in [Ca2+](m). When complete DeltaPsi(m) dissipation was achieved by FCCP (0.3-1 microM), [Ca2+](m) remained at one-half of the control level despite no Ca2+ influx via the Ca2+ uniporter. The DeltaPsi(m) dissipation by FCCP accelerated calcein leakage from mitochondria in a cyclosporin A (CsA)-sensitive manner, which indicates that DeltaPsi(m) dissipation opened the mitochondrial permeability transition pore (mPTP). After FCCP addition, inhibition of the mPTP by CsA caused further [Ca2+](m) reduction; however, inhibition of mitochondrial Na+/Ca2+ exchange (mitoNCX) by a Na+-free solution abolished this [Ca2+](m) reduction. Cytosolic Na(+) concentrations that yielded one-half maximal activity levels for mitoNCX were 3.6 mM at normal DeltaPsi(m) and 7.6 mM at DeltaPsi(m) dissipation. We conclude that 1) the mitochondrial Ca2+ uniporter accumulates Ca2+ in a manner that is dependent on DeltaPsi(m) at the physiological range of [Ca2+](c); 2) DeltaPsi(m) dissipation opens the mPTP and results in Ca2+ influx to mitochondria; and 3) although mitoNCX activity is impaired, mitoNCX extrudes Ca2+ from the matrix even after DeltaPsi(m) dissipation.
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Affiliation(s)
- Masao Saotome
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu 431-3192, Japan
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Li PL, Lee HC, Nelson MT, Meininger GA, Van Breemen C. Novel Ca2+ signalling mechanisms in vascular myocytes: symposium overview. ACTA ACUST UNITED AC 2004; 179:339-52. [PMID: 14656371 DOI: 10.1046/j.0001-6772.2003.01216.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This commentary presents the proceedings of the symposium sponsored by Cardiovascular Section of American Physiological Society in San Diego, CA on 12 April 2003. The major focus of this symposium was on the actions and physiological relevance of several novel Ca2+ signalling mechanisms in vascular smooth muscle (VSM) cells. Five important topics were presented in this symposium including the discovery and roles of cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP) in mediating Ca2+ release, Ca2+ sparks and activation of plasma membrane KCa channels in VSM cells, the role of cADPR-mediated activation of ryanodine receptors in the control of vascular tone, the role of [Ca2+]i in mechanotransduction in the arterioles, and interactions of mitochondrial Ca2+ release and SR Ca2+ mobilization. The purpose of this symposium was to promote discussions and exchange of ideas between scientists with interests in Ca2+ signalling mechanisms and those with interests in vascular physiology and pharmacology. The cross-fertilization of ideas is expected to greatly advance our understanding of the physiological and pharmacological relevance of these new Ca2+ signalling mechanisms.
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Affiliation(s)
- P-L Li
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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Poburko D, Lee CH, van Breemen C. Vascular smooth muscle mitochondria at the cross roads of Ca2+ regulation. Cell Calcium 2004; 35:509-21. [PMID: 15110141 DOI: 10.1016/j.ceca.2004.01.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Accepted: 01/25/2004] [Indexed: 11/22/2022]
Abstract
Mitochondria play an essential role in the regulation of vascular smooth muscle Ca(2+) signaling being simultaneously integrated in the regulation of ion channels and Ca(2+) transporters, oxygen radical production, metabolite recycling and intracellular redox potential. Mitochondria buffer Ca(2+) from cytoplasmic microdomains to alter the spatio-temporal pattern of Ca(2+) gradients following Ca(2+)-influx and Ca(2+)-release, and thus control site-specific, Ca(2+)-dependent ion channel activation and inactivation. The sub-cellular localization of mitochondria in conjunction with tissue-specific channel expression is fundamental to vascular heterogeneity. The mitochondrial electron transport chain recycles metabolic intermediates that modulate cellular redox potential and produces oxygen radicals in proportion to oxygen tension. Perturbation of specific complexes within the transport chain can affects NADH:NAD and ATP:ADP ratios and radical production, which can in turn influence second messenger metabolism, ion channel gating and Ca(2+)-transporter activity. Mitochondria thus provide the common ground for cross-talk between these regulatory systems that are mutually sensitive to one another. This cross-talk between signaling systems provides a means to render the physiological regulation of vascular tone responsive to complex stimulation by paracrine and endocrine factors, blood pressure and flow, tissue oxygenation and metabolic state.
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Affiliation(s)
- Damon Poburko
- The Department of Pharmacology and Therapeutics, The University of British Columbia, Vancouver, BC, Canada
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