1
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Shapiro IM, Risbud MV, Landis WJ. Toward understanding the cellular control of vertebrate mineralization: The potential role of mitochondria. Bone 2024; 185:117112. [PMID: 38697384 PMCID: PMC11251007 DOI: 10.1016/j.bone.2024.117112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/17/2024] [Accepted: 04/29/2024] [Indexed: 05/05/2024]
Abstract
This review examines the possible role of mitochondria in maintaining calcium and phosphate ion homeostasis and participating in the mineralization of bone, cartilage and other vertebrate hard tissues. The paper builds on the known structural features of mitochondria and the documented observations in these tissues that the organelles contain calcium phosphate granules. Such deposits in mitochondria putatively form to buffer excessively high cytosolic calcium ion concentrations and prevent metabolic deficits and even cell death. While mitochondria protect cytosolic enzyme systems through this buffering capacity, the accumulation of calcium ions by mitochondria promotes the activity of enzymes of the tricarboxylic acid (TCA/Krebs) cycle, increases oxidative phosphorylation and ATP synthesis, and leads to changes in intramitochondrial pH. These pH alterations influence ion solubility and possibly the transitions and composition in the mineral phase structure of the granules. Based on these considerations, mitochondria are proposed to support the mineralization process by providing a mobile store of calcium and phosphate ions, in smaller cluster or larger granule form, while maintaining critical cellular activities. The rise in the mitochondrial calcium level also increases the generation of citrate and other TCA cycle intermediates that contribute to cell function and the development of extracellular mineral. This paper suggests that another key role of the mitochondrion, along with the effects just noted, is to supply phosphate ions, derived from the breakdown of ATP, to endolysosomes and autophagic vesicles originating in the endoplasmic reticulum and Golgi and at the plasma membrane. These many separate but interdependent mitochondrial functions emphasize the critical importance of this organelle in the cellular control of vertebrate mineralization.
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Affiliation(s)
- Irving M Shapiro
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States of America.
| | - Makarand V Risbud
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States of America
| | - William J Landis
- Department of Preventive and Restorative Dental Sciences, School of Dentistry, University of California at San Francisco, San Francisco, CA, United States of America
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2
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Naón D, Hernández-Alvarez MI, Shinjo S, Wieczor M, Ivanova S, Martins de Brito O, Quintana A, Hidalgo J, Palacín M, Aparicio P, Castellanos J, Lores L, Sebastián D, Fernández-Veledo S, Vendrell J, Joven J, Orozco M, Zorzano A, Scorrano L. Splice variants of mitofusin 2 shape the endoplasmic reticulum and tether it to mitochondria. Science 2023; 380:eadh9351. [PMID: 37347868 DOI: 10.1126/science.adh9351] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 05/12/2023] [Indexed: 06/24/2023]
Abstract
In eukaryotic cells, different organelles interact at membrane contact sites stabilized by tethers. Mitochondrial mitofusin 2 (MFN2) acts as a membrane tether that interacts with an unknown partner on the endoplasmic reticulum (ER). In this work, we identified the MFN2 splice variant ERMIT2 as the ER tethering partner of MFN2. Splicing of MFN2 produced ERMIT2 and ERMIN2, two ER-specific variants. ERMIN2 regulated ER morphology, whereas ERMIT2 localized at the ER-mitochondria interface and interacted with mitochondrial mitofusins to tether ER and mitochondria. This tethering allowed efficient mitochondrial calcium ion uptake and phospholipid transfer. Expression of ERMIT2 ameliorated the ER stress, inflammation, and fibrosis typical of liver-specific Mfn2 knockout mice. Thus, ER-specific MFN2 variants display entirely extramitochondrial MFN2 functions involved in interorganellar tethering and liver metabolic activities.
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Affiliation(s)
- Déborah Naón
- Department of Biology, University of Padua, 35121 Padova, Italy
- Veneto Institute of Molecular Medicine, 35129 Padova, Italy
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain
| | - María Isabel Hernández-Alvarez
- Departament de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, Barcelona, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
- IBUB, Universitat de Barcelona, Barcelona, Spain
| | - Satoko Shinjo
- Department of Biology, University of Padua, 35121 Padova, Italy
- Veneto Institute of Molecular Medicine, 35129 Padova, Italy
| | - Milosz Wieczor
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain
- Department of Physical Chemistry, Gdansk University of Technology, 80-233 Gdańsk, Poland
| | - Saska Ivanova
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain
- Departament de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, Barcelona, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | | | - Albert Quintana
- Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Department of Cellular Biology, Physiology and Immunology, Animal Physiology Unit, Faculty of Biosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Juan Hidalgo
- Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Department of Cellular Biology, Physiology and Immunology, Animal Physiology Unit, Faculty of Biosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Manuel Palacín
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain
- Departament de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Pilar Aparicio
- Department of Orthopaedics and Trauma Surgery, Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Barcelona, Spain
| | - Juan Castellanos
- Department of Orthopaedics and Trauma Surgery, Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Barcelona, Spain
| | - Luis Lores
- Pneumology Department, Hospital General Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Barcelona, Spain
| | - David Sebastián
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain
- Departament de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, Barcelona, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Sonia Fernández-Veledo
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
- Department of Endocrinology and Nutrition, Hospital Universitari de Tarragona Joan XXIII, Institut d'Investigació Sanitària Pere Virgili (IISPV), Tarragona, Spain
- Medicine School, Universitat Rovira i Virgili, Tarragona and Reus, Spain
| | - Joan Vendrell
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
- Department of Endocrinology and Nutrition, Hospital Universitari de Tarragona Joan XXIII, Institut d'Investigació Sanitària Pere Virgili (IISPV), Tarragona, Spain
- Medicine School, Universitat Rovira i Virgili, Tarragona and Reus, Spain
| | - Jorge Joven
- Medicine School, Universitat Rovira i Virgili, Tarragona and Reus, Spain
- Unitat de Recerca Biomèdica, Institut d'Investigació Sanitària Pere Virgili, Hospital Universitari de Sant Joan, Reus, Spain
| | - Modesto Orozco
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain
- Departament de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, Barcelona, Spain
| | - Antonio Zorzano
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain
- Departament de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, Barcelona, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Luca Scorrano
- Department of Biology, University of Padua, 35121 Padova, Italy
- Veneto Institute of Molecular Medicine, 35129 Padova, Italy
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Bieżuńska-Kusiak K, Kulbacka J, Choromańska A, Rembiałkowska N, Michel O, Saczko J. Evaluation of the Anticancer Activity of Calcium Ions Introduced into Human Breast Adenocarcinoma Cells MCF-7/WT and MCF-7/DOX by Electroporation. Pharmaceuticals (Basel) 2023; 16:809. [PMID: 37375757 DOI: 10.3390/ph16060809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/18/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023] Open
Abstract
Breast cancer ranks among the top three most common malignant neoplasms in Poland. The use of calcium ion-assisted electroporation is an alternative approach to the classic treatment of this disease. The studies conducted in recent years confirm the effectiveness of electroporation with calcium ions. Electroporation is a method that uses short electrical pulses to create transitional pores in the cell membrane to allow the penetration of certain drugs. The aim of this study was to investigate the antitumor effects of electroporation alone and calcium ion-assisted electroporation on human mammary adenocarcinoma cells that are sensitive (MCF-7/WT) and resistant to doxorubicin (MCF-7/DOX). The cell viability was assessed using independent tests: MTT and SRB. The type of cell death after the applied therapy was determined by TUNEL and flow cytometry (FACS) methods. The expression of Cav3.1 and Cav3.2 proteins of T-type voltage-gated calcium channels was assessed by immunocytochemistry, and changes in the morphology of CaEP-treated cells were visualized using a holotomographic microscope. The obtained results confirmed the effectiveness of the investigated therapeutic method. The results of the work constitute a good basis for planning research at the in vivo level and in the future to develop a more effective and safer method of breast cancer treatment for patients.
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Affiliation(s)
- Katarzyna Bieżuńska-Kusiak
- Department of Molecular and Cellular Biology, Wroclaw Medical University, Borowska 211A, 50-556 Wroclaw, Poland
| | - Julita Kulbacka
- Department of Molecular and Cellular Biology, Wroclaw Medical University, Borowska 211A, 50-556 Wroclaw, Poland
- Department of Immunology, State Research Institute Centre for Innovative Medicine, Santariškių 5, 08410 Vilnius, Lithuania
| | - Anna Choromańska
- Department of Molecular and Cellular Biology, Wroclaw Medical University, Borowska 211A, 50-556 Wroclaw, Poland
| | - Nina Rembiałkowska
- Department of Molecular and Cellular Biology, Wroclaw Medical University, Borowska 211A, 50-556 Wroclaw, Poland
| | - Olga Michel
- Department of Cytobiochemistry, University of Wroclaw, F. Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Jolanta Saczko
- Department of Molecular and Cellular Biology, Wroclaw Medical University, Borowska 211A, 50-556 Wroclaw, Poland
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Thakkar P, Pauza AG, Murphy D, Paton JFR. Carotid body: an emerging target for cardiometabolic co-morbidities. Exp Physiol 2023; 108:661-671. [PMID: 36999224 PMCID: PMC10988524 DOI: 10.1113/ep090090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 03/03/2023] [Indexed: 04/01/2023]
Abstract
NEW FINDINGS What is the topic of this review? Regarding the global metabolic syndrome crisis, this review focuses on common mechanisms for high blood sugar and high blood pressure. Connections are made between the homeostatic regulation of blood pressure and blood sugar and their dysregulation to reveal signalling mechanisms converging on the carotid body. What advances does it highlight? The carotid body plays a major part in the generation of excessive sympathetic activity in diabetes and also underpins diabetic hypertension. As treatment of diabetic hypertension is notoriously difficult, we propose that novel receptors within the carotid body may provide a novel treatment strategy. ABSTRACT The maintenance of glucose homeostasis is obligatory for health and survival. It relies on peripheral glucose sensing and signalling between the brain and peripheral organs via hormonal and neural responses that restore euglycaemia. Failure of these mechanisms causes hyperglycaemia or diabetes. Current anti-diabetic medications control blood glucose but many patients remain with hyperglycemic condition. Diabetes is often associated with hypertension; the latter is more difficult to control in hyperglycaemic conditions. We ask whether a better understanding of the regulatory mechanisms of glucose control could improve treatment of both diabetes and hypertension when they co-exist. With the involvement of the carotid body (CB) in glucose sensing, metabolic regulation and control of sympathetic nerve activity, we consider the CB as a potential treatment target for both diabetes and hypertension. We provide an update on the role of the CB in glucose sensing and glucose homeostasis. Physiologically, hypoglycaemia stimulates the release of hormones such as glucagon and adrenaline, which mobilize or synthesize glucose; however, these counter-regulatory responses were markedly attenuated after denervation of the CBs in animals. Also, CB denervation prevents and reverses insulin resistance and glucose intolerance. We discuss the CB as a metabolic regulator (not just a sensor of blood gases) and consider recent evidence of novel 'metabolic' receptors within the CB and putative signalling peptides that may control glucose homeostasis via modulation of the sympathetic nervous system. The evidence presented may inform future clinical strategies in the treatment of patients with both diabetes and hypertension, which may include the CB.
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Affiliation(s)
- Pratik Thakkar
- Manaaki Manawa – the Centre for Heart Research, Department of Physiology, Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
| | - Audrys G. Pauza
- Manaaki Manawa – the Centre for Heart Research, Department of Physiology, Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
| | - David Murphy
- Molecular Neuroendocrinology Research Group, Bristol Medical School: Translational Health SciencesUniversity of BristolBristolUK
| | - Julian F. R. Paton
- Manaaki Manawa – the Centre for Heart Research, Department of Physiology, Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
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5
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Zhou X, Li A, Lin PH, Zhou J, Ma J. TRIC-A regulates intracellular Ca 2+ homeostasis in cardiomyocytes. Pflugers Arch 2021; 473:547-556. [PMID: 33474637 PMCID: PMC7940156 DOI: 10.1007/s00424-021-02513-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/14/2020] [Accepted: 01/04/2021] [Indexed: 01/26/2023]
Abstract
Trimeric intracellular cation (TRIC) channels have been identified as monovalent cation channels that are located in the ER/SR membrane. Two isoforms discovered in mammals are TRIC-A (TMEM38a) and TRIC-B (TMEM38b). TRIC-B ubiquitously expresses in all tissues, and TRIC-B-/- mice is lethal at the neonatal stage. TRIC-A mainly expresses in excitable cells. TRIC-A-/- mice survive normally but show abnormal SR Ca2+ handling in both skeletal and cardiac muscle cells. Importantly, TRIC-A mutations have been identified in human patients with stress-induced arrhythmia. In the past decade, important discoveries have been made to understand the structure and function of TRIC channels, especially its role in regulating intracellular Ca2+ homeostasis. In this review article, we focus on the potential roles of TRIC-A in regulating cardiac function, particularly its effects on intracellular Ca2+ signaling of cardiomyocytes and discuss the current knowledge gaps.
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Affiliation(s)
- Xinyu Zhou
- Department of Surgery, The Ohio State University Columbus, Columbus, OH, 43210, USA
| | - Ang Li
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, 76019, USA
| | - Pei-Hui Lin
- Department of Surgery, The Ohio State University Columbus, Columbus, OH, 43210, USA
| | - Jingsong Zhou
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, 76019, USA
| | - Jianjie Ma
- Department of Surgery, The Ohio State University Columbus, Columbus, OH, 43210, USA.
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6
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Cortassa S, Juhaszova M, Aon MA, Zorov DB, Sollott SJ. Mitochondrial Ca 2+, redox environment and ROS emission in heart failure: Two sides of the same coin? J Mol Cell Cardiol 2021; 151:113-125. [PMID: 33301801 PMCID: PMC7880885 DOI: 10.1016/j.yjmcc.2020.11.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 11/05/2020] [Accepted: 11/28/2020] [Indexed: 12/11/2022]
Abstract
Heart failure (HF) is a progressive, debilitating condition characterized, in part, by altered ionic equilibria, increased ROS production and impaired cellular energy metabolism, contributing to variable profiles of systolic and diastolic dysfunction with significant functional limitations and risk of premature death. We summarize current knowledge concerning changes of intracellular Na+ and Ca2+ control mechanisms during the disease progression and their consequences on mitochondrial Ca2+ homeostasis and the shift in redox balance. Absent existing biological data, our computational modeling studies advance a new 'in silico' analysis to reconcile existing opposing views, based on different experimental HF models, regarding variations in mitochondrial Ca2+ concentration that participate in triggering and perpetuating oxidative stress in the failing heart and their impact on cardiac energetics. In agreement with our hypothesis and the literature, model simulations demonstrate the possibility that the heart's redox status together with cytoplasmic Na+ concentrations act as regulators of mitochondrial Ca2+ levels in HF and of the bioenergetics response that will ultimately drive ATP supply and oxidative stress. The resulting model predictions propose future directions to study the evolution of HF as well as other types of heart disease, and to develop novel testable mechanistic hypotheses that may lead to improved therapeutics.
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Affiliation(s)
- Sonia Cortassa
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD, United States.
| | - Magdalena Juhaszova
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD, United States.
| | - Miguel A Aon
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD, United States; Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD, United States.
| | - Dmitry B Zorov
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD, United States; Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.
| | - Steven J Sollott
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD, United States.
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7
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Hamilton J, Brustovetsky T, Brustovetsky N. The effect of mitochondrial calcium uniporter and cyclophilin D knockout on resistance of brain mitochondria to Ca 2+-induced damage. J Biol Chem 2021; 296:100669. [PMID: 33864812 PMCID: PMC8131324 DOI: 10.1016/j.jbc.2021.100669] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/10/2021] [Accepted: 04/13/2021] [Indexed: 12/14/2022] Open
Abstract
The mitochondrial calcium uniporter (MCU) and cyclophilin D (CyD) are key players in induction of the permeability transition pore (PTP), which leads to mitochondrial depolarization and swelling, the major signs of Ca2+-induced mitochondrial damage. Mitochondrial depolarization inhibits ATP production, whereas swelling results in the release of mitochondrial pro-apoptotic proteins. The extent to which simultaneous deletion of MCU and CyD inhibits PTP induction and prevents damage of brain mitochondria is not clear. Here, we investigated the effects of MCU and CyD deletion on the propensity for PTP induction using mitochondria isolated from the brains of MCU-KO, CyD-KO, and newly created MCU/CyD-double knockout (DKO) mice. Neither deletion of MCU nor of CyD affected respiration or membrane potential in mitochondria isolated from the brains of these mice. Mitochondria from MCU-KO and MCU/CyD-DKO mice displayed reduced Ca2+ uptake and diminished extent of PTP induction. The Ca2+ uptake by mitochondria from CyD-KO mice was increased compared with mitochondria from WT mice. Deletion of CyD prevented mitochondrial swelling and resulted in transient depolarization in response to Ca2+, but it did not prevent Ca2+-induced delayed mitochondrial depolarization. Mitochondria from MCU/CyD-DKO mice did not swell in response to Ca2+, but they did exhibit mild sustained depolarization. Dibucaine, an inhibitor of the Ca2+-activated mitochondrial phospholipase A2, attenuated and bovine serum albumin completely eliminated the sustained depolarization. This suggests the involvement of phospholipase A2 and free fatty acids. Thus, in addition to induction of the classical PTP, alternative deleterious mechanisms may contribute to mitochondrial damage following exposure to elevated Ca2+.
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Affiliation(s)
- James Hamilton
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Tatiana Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Nickolay Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA.
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Abstract
T cells are an essential component of the immune system that provide antigen-specific acute and long lasting immune responses to infections and tumors, ascertain the maintenance of immunological tolerance and, on the flipside, mediate autoimmunity in a variety of diseases. The activation of T cells through antigen recognition by the T cell receptor (TCR) results in transient and sustained Ca2+ signals that are shaped by the opening of Ca2+ channels in the plasma membrane and cellular organelles. The dynamic regulation of intracellular Ca2+ concentrations controls a variety of T cell functions on the timescale of seconds to days after signal initiation. Among the more recently identified roles of Ca2+ signaling in T cells is the regulation of metabolic pathways that control the function of many T cell subsets. In this review, we discuss how Ca2+ regulates several metabolic programs in T cells such as the activation of AMPK and the PI3K-AKT-mTORC1 pathway, aerobic glycolysis, mitochondrial metabolism including tricarboxylic acid (TCA) cycle function and oxidative phosphorylation (OXPHOS), as well as lipid metabolism.
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Affiliation(s)
- Yinhu Wang
- Department of Pathology, New York University School of Medicine, New York, NY, USA
| | - Anthony Tao
- Department of Pathology, New York University School of Medicine, New York, NY, USA
| | - Martin Vaeth
- Institute of Systems Immunology, Julius Maximilians University of Würzburg, Würzburg, Germany
| | - Stefan Feske
- Department of Pathology, New York University School of Medicine, New York, NY, USA
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Diaz-Juarez J, Suarez JA, Dillmann WH, Suarez J. Mitochondrial calcium handling and heart disease in diabetes mellitus. Biochim Biophys Acta Mol Basis Dis 2020; 1867:165984. [PMID: 33002576 DOI: 10.1016/j.bbadis.2020.165984] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 01/23/2023]
Abstract
Diabetes mellitus-induced heart disease, including diabetic cardiomyopathy, is an important medical problem and is difficult to treat. Diabetes mellitus increases the risk for heart failure and decreases cardiac myocyte function, which are linked to changes in cardiac mitochondrial energy metabolism. The free mitochondrial calcium concentration ([Ca2+]m) is fundamental in activating the mitochondrial respiratory chain complexes and ATP production and is also known to regulate the activity of key mitochondrial dehydrogenases. The mitochondrial calcium uniporter complex (MCUC) plays a major role in mediating mitochondrial Ca2+ import, and its expression and function therefore may have a marked impact on cardiac myocyte metabolism and function. Here, we summarize the pathophysiological role of [Ca2+]m handling and MCUC in the diabetic heart. In addition, we evaluate potential therapeutic targets, directed to the machinery that regulates mitochondrial calcium handling, to alleviate diabetes-related cardiac disease.
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Affiliation(s)
- Julieta Diaz-Juarez
- Department of Pharmacology, Instituto Nacional de Cardiología, Juan Badiano No. 1, Col. Seccion XVI, 14080 Tlalpan, Ciudad de Mexico, Mexico
| | - Jorge A Suarez
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Wolfgang H Dillmann
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Jorge Suarez
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
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10
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Cao JL, Adaniya SM, Cypress MW, Suzuki Y, Kusakari Y, Jhun BS, O-Uchi J. Role of mitochondrial Ca 2+ homeostasis in cardiac muscles. Arch Biochem Biophys 2019; 663:276-287. [PMID: 30684463 PMCID: PMC6469710 DOI: 10.1016/j.abb.2019.01.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/10/2019] [Accepted: 01/22/2019] [Indexed: 12/22/2022]
Abstract
Recent discoveries of the molecular identity of mitochondrial Ca2+ influx/efflux mechanisms have placed mitochondrial Ca2+ transport at center stage in views of cellular regulation in various cell-types/tissues. Indeed, mitochondria in cardiac muscles also possess the molecular components for efficient uptake and extraction of Ca2+. Over the last several years, multiple groups have taken advantage of newly available molecular information about these proteins and applied genetic tools to delineate the precise mechanisms for mitochondrial Ca2+ handling in cardiomyocytes and its contribution to excitation-contraction/metabolism coupling in the heart. Though mitochondrial Ca2+ has been proposed as one of the most crucial secondary messengers in controlling a cardiomyocyte's life and death, the detailed mechanisms of how mitochondrial Ca2+ regulates physiological mitochondrial and cellular functions in cardiac muscles, and how disorders of this mechanism lead to cardiac diseases remain unclear. In this review, we summarize the current controversies and discrepancies regarding cardiac mitochondrial Ca2+ signaling that remain in the field to provide a platform for future discussions and experiments to help close this gap.
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Affiliation(s)
- Jessica L Cao
- Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, USA; Department of Medicine, Division of Cardiology, The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Stephanie M Adaniya
- Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, USA; Department of Medicine, Division of Cardiology, The Warren Alpert Medical School of Brown University, Providence, RI, USA; Lillehei Heart Institute, Department of Medicine, Cardiovascular Division, University of Minnesota, Minneapolis, MN, USA
| | - Michael W Cypress
- Lillehei Heart Institute, Department of Medicine, Cardiovascular Division, University of Minnesota, Minneapolis, MN, USA
| | - Yuta Suzuki
- Lillehei Heart Institute, Department of Medicine, Cardiovascular Division, University of Minnesota, Minneapolis, MN, USA
| | - Yoichiro Kusakari
- Department of Cell Physiology, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Bong Sook Jhun
- Lillehei Heart Institute, Department of Medicine, Cardiovascular Division, University of Minnesota, Minneapolis, MN, USA
| | - Jin O-Uchi
- Lillehei Heart Institute, Department of Medicine, Cardiovascular Division, University of Minnesota, Minneapolis, MN, USA.
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11
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Doliba NM, Babsky AM, Osbakken MD. The Role of Sodium in Diabetic Cardiomyopathy. Front Physiol 2018; 9:1473. [PMID: 30405433 PMCID: PMC6207851 DOI: 10.3389/fphys.2018.01473] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 09/28/2018] [Indexed: 12/11/2022] Open
Abstract
Cardiovascular complications are the major cause of mortality and morbidity in diabetic patients. The changes in myocardial structure and function associated with diabetes are collectively called diabetic cardiomyopathy. Numerous molecular mechanisms have been proposed that could contribute to the development of diabetic cardiomyopathy and have been studied in various animal models of type 1 or type 2 diabetes. The current review focuses on the role of sodium (Na+) in diabetic cardiomyopathy and provides unique data on the linkage between Na+ flux and energy metabolism, studied with non-invasive 23Na, and 31P-NMR spectroscopy, polarography, and mass spectroscopy. 23Na NMR studies allow determination of the intracellular and extracellular Na+ pools by splitting the total Na+ peak into two resonances after the addition of a shift reagent to the perfusate. Using this technology, we found that intracellular Na+ is approximately two times higher in diabetic cardiomyocytes than in control possibly due to combined changes in the activity of Na+–K+ pump, Na+/H+ exchanger 1 (NHE1) and Na+-glucose cotransporter. We hypothesized that the increase in Na+ activates the mitochondrial membrane Na+/Ca2+ exchanger, which leads to a loss of intramitochondrial Ca2+, with a subsequent alteration in mitochondrial bioenergetics and function. Using isolated mitochondria, we showed that the addition of Na+ (1–10 mM) led to a dose-dependent decrease in oxidative phosphorylation and that this effect was reversed by providing extramitochondrial Ca2+ or by inhibiting the mitochondrial Na+/Ca2+ exchanger with diltiazem. Similar experiments with 31P-NMR in isolated superfused mitochondria embedded in agarose beads showed that Na+ (3–30 mM) led to significantly decreased ATP levels and that this effect was stronger in diabetic rats. These data suggest that in diabetic cardiomyocytes, increased Na+ leads to abnormalities in oxidative phosphorylation and a subsequent decrease in ATP levels. In support of these data, using 31P-NMR, we showed that the baseline β-ATP and phosphocreatine (PCr) were lower in diabetic cardiomyocytes than in control, suggesting that diabetic cardiomyocytes have depressed bioenergetic function. Thus, both altered intracellular Na+ levels and bioenergetics and their interactions may significantly contribute to the pathology of diabetic cardiomyopathy.
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Affiliation(s)
- Nicolai M Doliba
- Department of Biochemistry and Biophysics, Institute for Diabetes, Obesity and Metabolism, School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Andriy M Babsky
- Department of Biophysics and Bioinformatics, Ivan Franko National University of Lviv, Lviv, Ukraine
| | - Mary D Osbakken
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, United States
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12
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Salimi A, Gholamifar E, Naserzadeh P, Hosseini MJ, Pourahmad J. Toxicity of lithium on isolated heart mitochondria and cardiomyocyte: A justification for its cardiotoxic adverse effect. J Biochem Mol Toxicol 2016; 31. [PMID: 27588890 DOI: 10.1002/jbt.21836] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 07/24/2016] [Accepted: 08/10/2016] [Indexed: 11/12/2022]
Abstract
Mitochondria play an important role in myocardial tissue homeostasis; therefore, deterioration in mitochondrial function will eventually lead to cardiomyocyte and endothelial cell death and consequently cardiovascular dysfunction. Lithium (Li+ ) is an effective drug for bipolar disorder with known cardiotoxic side effects. This study was designed to investigate the effects of Li+ on mitochondria and cardiomyocytes isolated from the heart of Wistar rat. Results revealed that Li+ induced a concentration- and time-dependent rise in mitochondrial ROS formation, inhibition of respiratory complexes (II), mitochondrial membrane potential (MMP) collapse, mitochondrial swelling, and cytochrome c release in rat heart mitochondria and also induced Caspase 3 activation through mitochondrial pathway, decline of ATP and lipid peroxidation in rat cardiomyocytes. These results indicate that the cardiotoxic effects of Li+ were initiated from mitochondrial dysfunction and oxidative stress, which finally ends in cytochrome c release and cell death signaling heart cardiomyocytes.
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Affiliation(s)
- Ahmad Salimi
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Students Research Committee, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Pharmacology and Toxicology, School of Pharmacy, Ardabil University of Medical Science, Ardabil, Iran
| | - Ehsan Gholamifar
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Parvaneh Naserzadeh
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Pharmacology and Toxicology, School of Pharmacy, Ardabil University of Medical Science, Ardabil, Iran
| | - Mir-Jamal Hosseini
- Zanjan Applied Pharmacology Research Center, Zanjan University of Medical Sciences, Zanjan, Iran.,Department of Pharmacology and Toxicology, School of Pharmacy, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Jalal Pourahmad
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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13
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Raut MP, Couto N, Pham TK, Evans C, Noirel J, Wright PC. Quantitative proteomic analysis of the influence of lignin on biofuel production by Clostridium acetobutylicum ATCC 824. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:113. [PMID: 27247624 PMCID: PMC4886415 DOI: 10.1186/s13068-016-0523-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 05/09/2016] [Indexed: 05/30/2023]
Abstract
BACKGROUND Clostridium acetobutylicum has been a focus of research because of its ability to produce high-value compounds that can be used as biofuels. Lignocellulose is a promising feedstock, but the lignin-cellulose-hemicellulose biomass complex requires chemical pre-treatment to yield fermentable saccharides, including cellulose-derived cellobiose, prior to bioproduction of acetone-butanol-ethanol (ABE) and hydrogen. Fermentation capability is limited by lignin and thus process optimization requires knowledge of lignin inhibition. The effects of lignin on cellular metabolism were evaluated for C. acetobutylicum grown on medium containing either cellobiose only or cellobiose plus lignin. Microscopy, gas chromatography and 8-plex iTRAQ-based quantitative proteomic technologies were applied to interrogate the effect of lignin on cellular morphology, fermentation and the proteome. RESULTS Our results demonstrate that C. acetobutylicum has reduced performance for solvent production when lignin is present in the medium. Medium supplemented with 1 g L(-1) of lignin led to delay and decreased solvents production (ethanol; 0.47 g L(-1) for cellobiose and 0.27 g L(-1) for cellobiose plus lignin and butanol; 0.13 g L(-1) for cellobiose and 0.04 g L(-1) for cellobiose plus lignin) at 20 and 48 h, respectively, resulting in the accumulation of acetic acid and butyric acid. Of 583 identified proteins (FDR < 1 %), 328 proteins were quantified with at least two unique peptides. Up- or down-regulation of protein expression was determined by comparison of exponential and stationary phases of cellobiose in the presence and absence of lignin. Of relevance, glycolysis and fermentative pathways were mostly down-regulated, during exponential and stationary growth phases in presence of lignin. Moreover, proteins involved in DNA repair, transcription/translation and GTP/ATP-dependent activities were also significantly affected and these changes were associated with altered cell morphology. CONCLUSIONS This is the first comprehensive analysis of the cellular responses of C. acetobutylicum to lignin at metabolic and physiological levels. These data will enable targeted metabolic engineering strategies to optimize biofuel production from biomass by overcoming limitations imposed by the presence of lignin.
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Affiliation(s)
- Mahendra P. Raut
- />The ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD UK
| | - Narciso Couto
- />The ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD UK
| | - Trong K. Pham
- />The ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD UK
| | - Caroline Evans
- />The ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD UK
| | - Josselin Noirel
- />The ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD UK
- />Chaire de Bioinformatique, LGBA, Conservatoire National Des Arts Et Métiers, 75003 Paris, France
| | - Phillip C. Wright
- />The ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD UK
- />School of Chemical Engineering and Advanced Materials, Faculty of Science, Agriculture & Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU UK
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14
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Williams GSB, Boyman L, Lederer WJ. Mitochondrial calcium and the regulation of metabolism in the heart. J Mol Cell Cardiol 2014; 78:35-45. [PMID: 25450609 DOI: 10.1016/j.yjmcc.2014.10.019] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 01/28/2023]
Abstract
Consumption of adenosine triphosphate (ATP) by the heart can change dramatically as the energetic demands increase from a period of rest to strenuous activity. Mitochondrial ATP production is central to this metabolic response since the heart relies largely on oxidative phosphorylation as its source of intracellular ATP. Significant evidence has been acquired indicating that Ca(2+) plays a critical role in regulating ATP production by the mitochondria. Here the evidence that the Ca(2+) concentration in the mitochondrial matrix ([Ca(2+)]m) plays a pivotal role in regulating ATP production by the mitochondria is critically reviewed and aspects of this process that are under current active investigation are highlighted. Importantly, current quantitative information on the bidirectional Ca(2+) movement across the inner mitochondrial membrane (IMM) is examined in two parts. First, we review how Ca(2+) influx into the mitochondrial matrix depends on the mitochondrial Ca(2+) channel (i.e., the mitochondrial calcium uniporter or MCU). This discussion includes how the MCU open probability (PO) depends on the cytosolic Ca(2+) concentration ([Ca(2+)]i) and on the mitochondrial membrane potential (ΔΨm). Second, we discuss how steady-state [Ca(2+)]m is determined by the dynamic balance between this MCU-based Ca(2+) influx and mitochondrial Na(+)/Ca(2+) exchanger (NCLX) based Ca(2+) efflux. These steady-state [Ca(2+)]m levels are suggested to regulate the metabolic energy supply due to Ca(2+)-dependent regulation of mitochondrial enzymes of the tricarboxylic acid cycle (TCA), the proteins of the electron transport chain (ETC), and the F1F0 ATP synthase itself. We conclude by discussing the roles played by [Ca(2+)]m in influencing mitochondrial responses under pathological conditions. This article is part of a Special Issue entitled "Mitochondria: From BasicMitochondrial Biology to Cardiovascular Disease."
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Affiliation(s)
- George S B Williams
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Liron Boyman
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - W Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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15
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Acute and chronic effects of bupivacaine on muscle energetics during contraction in vivo: a modular metabolic control analysis. Biochem J 2012; 444:315-21. [DOI: 10.1042/bj20112011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Bupivacaine is a widely used anaesthetic injected locally in clinical practice for short-term neurotransmission blockade. However, persistent side effects on mitochondrial integrity have been demonstrated in muscle parts surrounding the injection site. We use the precise language of metabolic control analysis in the present study to describe in vivo consequences of bupivacaine injection on muscle energetics during contraction. We define a model system of muscle energy metabolism in rats with a sciatic nerve catheter that consists of two modules of reactions, ATP/PCr (phosphocreatine) supply and ATP/PCr demand, linked by the common intermediate PCr detected in vivo by 31P-MRS (magnetic resonance spectroscopy). Measured system variables were [PCr] (intermediate) and contraction (flux). We first applied regulation analysis to quantify acute effects of bupivacaine. After bupivacaine injection, contraction decreased by 15.7% and, concomitantly, [PCr] increased by 11.2%. The regulation analysis quantified that demand was in fact directly inhibited by bupivacaine (−21.3%), causing an increase in PCr. This increase in PCr indirectly reduced mitochondrial activity (−22.4%). Globally, the decrease in contractions was almost fully explained by inhibition of demand (−17.0%) without significant effect through energy supply. Finally we applied elasticity analysis to quantify chronic effects of bupivacaine iterative injections. The absence of a difference in elasticities obtained in treated rats when compared with healthy control rats clearly shows the absence of dysfunction in energetic control of muscle contraction energetics. The present study constitutes the first and direct evidence that bupivacaine myotoxicity is compromised by other factors during contraction in vivo, and illustrates the interest of modular approaches to appreciate simple rules governing bioenergetic systems when affected by drugs.
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16
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Youm JB, Choi SW, Jang CH, Kim HK, Leem CH, Kim N, Han J. A computational model of cytosolic and mitochondrial [ca] in paced rat ventricular myocytes. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2011; 15:217-39. [PMID: 21994480 DOI: 10.4196/kjpp.2011.15.4.217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 08/09/2011] [Accepted: 08/09/2011] [Indexed: 11/15/2022]
Abstract
We carried out a series of experiment demonstrating the role of mitochondria in the cytosolic and mitochondrial Ca(2+) transients and compared the results with those from computer simulation. In rat ventricular myocytes, increasing the rate of stimulation (1~3 Hz) made both the diastolic and systolic [Ca(2+)] bigger in mitochondria as well as in cytosol. As L-type Ca(2+) channel has key influence on the amplitude of Ca(2+)-induced Ca(2+) release, the relation between stimulus frequency and the amplitude of Ca(2+) transients was examined under the low density (1/10 of control) of L-type Ca(2+) channel in model simulation, where the relation was reversed. In experiment, block of Ca(2+) uniporter on mitochondrial inner membrane significantly reduced the amplitude of mitochondrial Ca(2+) transients, while it failed to affect the cytosolic Ca(2+) transients. In computer simulation, the amplitude of cytosolic Ca(2+) transients was not affected by removal of Ca(2+) uniporter. The application of carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP) known as a protonophore on mitochondrial membrane to rat ventricular myocytes gradually increased the diastolic [Ca(2+)] in cytosol and eventually abolished the Ca(2+) transients, which was similarly reproduced in computer simulation. The model study suggests that the relative contribution of L-type Ca(2+) channel to total transsarcolemmal Ca(2+) flux could determine whether the cytosolic Ca(2+) transients become bigger or smaller with higher stimulus frequency. The present study also suggests that cytosolic Ca(2+) affects mitochondrial Ca(2+) in a beat-to-beat manner, however, removal of Ca(2+) influx mechanism into mitochondria does not affect the amplitude of cytosolic Ca(2+) transients.
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Affiliation(s)
- Jae Boum Youm
- National Research Laboratory for Mitochondrial Signaling, Department of Physiology, College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
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17
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Kawamata H, Manfredi G. Mitochondrial dysfunction and intracellular calcium dysregulation in ALS. Mech Ageing Dev 2010; 131:517-26. [PMID: 20493207 PMCID: PMC2933290 DOI: 10.1016/j.mad.2010.05.003] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 05/05/2010] [Accepted: 05/12/2010] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder that affects the aging population. A progressive loss of motor neurons in the spinal cord and brain leads to muscle paralysis and death. As in other common neurodegenerative diseases, aging-related mitochondrial dysfunction is increasingly being considered among the pathogenic factors. Mitochondria are critical for cell survival: they provide energy to the cell, buffer intracellular calcium, and regulate apoptotic cell death. Whether mitochondrial abnormalities are a trigger or a consequence of the neurodegenerative process and the mechanisms whereby mitochondrial dysfunction contributes to disease are not clear yet. Calcium homeostasis is a major function of mitochondria in neurons, and there is ample evidence that intracellular calcium is dysregulated in ALS. The impact of mitochondrial dysfunction on intracellular calcium homeostasis and its role in motor neuron demise are intriguing issues that warrants in depth discussion. Clearly, unraveling the causal relationship between mitochondrial dysfunction, calcium dysregulation, and neuronal death is critical for the understanding of ALS pathogenesis. In this review, we will outline the current knowledge of various aspects of mitochondrial dysfunction in ALS, with a special emphasis on the role of these abnormalities on intracellular calcium handling.
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Affiliation(s)
- Hibiki Kawamata
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY 10065, USA
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18
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The dual role of calcium as messenger and stressor in cell damage, death, and survival. Int J Cell Biol 2010; 2010:546163. [PMID: 20300548 PMCID: PMC2838366 DOI: 10.1155/2010/546163] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 11/15/2009] [Accepted: 01/06/2010] [Indexed: 02/07/2023] Open
Abstract
Ca(2+) is an important second messenger participating in many cellular activities; when physicochemical insults deregulate its delicate homeostasis, it acts as an intrinsic stressor, producing/increasing cell damage. Damage elicits both repair and death responses; intriguingly, in those responses Ca(2+) also participates as second messenger. This delineates a dual role for Ca(2+) in cell stress, making difficult to separate the different and multiple mechanisms required for Ca(2+)-mediated control of cell survival and apoptosis. Here we attempt to disentangle the two scenarios, examining on the one side, the events implicated in deregulated Ca(2+) toxicity and the mechanisms through which this elicits reparative or death pathways; on the other, reviewing the role of Ca(2+) as a messenger in the transduction of these same signaling events.
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19
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Acin-Perez R, Salazar E, Brosel S, Yang H, Schon EA, Manfredi G. Modulation of mitochondrial protein phosphorylation by soluble adenylyl cyclase ameliorates cytochrome oxidase defects. EMBO Mol Med 2010; 1:392-406. [PMID: 20049744 PMCID: PMC2814779 DOI: 10.1002/emmm.200900046] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Phosphorylation of respiratory chain components has emerged as a mode of regulation of mitochondrial energy metabolism, but its mechanisms are still largely unexplored. A recently discovered intramitochondrial signalling pathway links CO2 generated by the Krebs cycle with the respiratory chain, through the action of a mitochondrial soluble adenylyl cyclase (mt-sAC). Cytochrome oxidase (COX), whose deficiency causes a number of fatal metabolic disorders, is a key mitochondrial enzyme activated by mt-sAC. We have now discovered that the mt-sAC pathway modulates mitochondrial biogenesis in a reactive oxygen species dependent manner, in cultured cells and in animals with COX deficiency. We show that upregulation of mt-sAC normalizes reactive oxygen species production and mitochondrial biogenesis, thereby restoring mitochondrial function. This is the first example of manipulation of a mitochondrial signalling pathway to achieve a direct positive modulation of COX, with clear implications for the development of novel approaches to treat mitochondrial diseases.
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Affiliation(s)
- Rebeca Acin-Perez
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY, USA
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20
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Liu T, O’Rourke B. Regulation of mitochondrial Ca2+ and its effects on energetics and redox balance in normal and failing heart. J Bioenerg Biomembr 2009; 41:127-32. [PMID: 19390955 PMCID: PMC2946065 DOI: 10.1007/s10863-009-9216-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Ca(2+) has been well accepted as a signal that coordinates changes in cytosolic workload with mitochondrial energy metabolism in cardiomyocytes. During increased work, Ca(2+) is accumulated in mitochondria and stimulates ATP production to match energy supply and demand. The kinetics of mitochondrial Ca(2+) ([Ca(2+)](m)) uptake remains unclear, and we review the debate on this subject in this article. [Ca(2+)](m) has multiple targets in oxidative phosphorylation including the F1/FO ATPase, the adenine nucleotide translocase, and Ca(2+)-sensitive dehydrogenases (CaDH) of the tricarboxylic acid (TCA) cycle. The well established effect of [Ca(2+)](m) is to activate CaDHs of the TCA cycle to increase NADH production. Maintaining NADH level is not only critical to keep a high oxidative phosphorylation rate during increased cardiac work, but is also necessary for the reducing system of the cell to maintain its reactive oxygen species (ROS) -scavenging capacity. Further, we review recent data demonstrating the deleterious effects of elevated Na(+) in cardiac pathology by blunting [Ca(2+)](m) accumulation.
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Affiliation(s)
- Ting Liu
- Institute of Molecular Cardiobiology, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA
| | - Brian O’Rourke
- Institute of Molecular Cardiobiology, The Johns Hopkins University, 720 Rutland Ave., 1060 Ross Bldg., Baltimore, MD 21205-2195, USA,
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21
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Liu W, Vives-Bauza C, Acín-Peréz- R, Yamamoto A, Tan Y, Li Y, Magrané J, Stavarache MA, Shaffer S, Chang S, Kaplitt MG, Huang XY, Beal MF, Manfredi G, Li C. PINK1 defect causes mitochondrial dysfunction, proteasomal deficit and alpha-synuclein aggregation in cell culture models of Parkinson's disease. PLoS One 2009; 4:e4597. [PMID: 19242547 PMCID: PMC2644779 DOI: 10.1371/journal.pone.0004597] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Accepted: 01/20/2009] [Indexed: 12/21/2022] Open
Abstract
Mutations in PTEN induced kinase 1 (PINK1), a mitochondrial Ser/Thr kinase, cause an autosomal recessive form of Parkinson's disease (PD), PARK6. Here, we report that PINK1 exists as a dimer in mitochondrial protein complexes that co-migrate with respiratory chain complexes in sucrose gradients. PARK6 related mutations do not affect this dimerization and its associated complexes. Using in vitro cell culture systems, we found that mutant PINK1 or PINK1 knock-down caused deficits in mitochondrial respiration and ATP synthesis. Furthermore, proteasome function is impaired with a loss of PINK1. Importantly, these deficits are accompanied by increased alpha-synclein aggregation. Our results indicate that it will be important to delineate the relationship between mitochondrial functional deficits, proteasome dysfunction and alpha-synclein aggregation.
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Affiliation(s)
- Wencheng Liu
- Department of Neurology and Neurosciences, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Cristofol Vives-Bauza
- Department of Neurology and Neurosciences, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Rebeca Acín-Peréz-
- Department of Neurology and Neurosciences, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Ai Yamamoto
- Judith P. Sulzberger M.D. Columbia Genome Center and Department of Physiology and Cellular Biophysics, Columbia University, New York, New York, United States of America
| | - Yingcai Tan
- Department of Physiology, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Yanping Li
- Department of Neurology and Neurosciences, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Jordi Magrané
- Department of Neurology and Neurosciences, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Mihaela A. Stavarache
- Department of Neurological Surgery, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Sebastian Shaffer
- Department of Neurology and Neurosciences, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Simon Chang
- Department of Neurology and Neurosciences, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Michael G. Kaplitt
- Department of Neurological Surgery, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Xin-Yun Huang
- Department of Physiology, Weill Medical College of Cornell University, New York, New York, United States of America
| | - M. Flint Beal
- Department of Neurology and Neurosciences, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Giovanni Manfredi
- Department of Neurology and Neurosciences, Weill Medical College of Cornell University, New York, New York, United States of America
- * E-mail: (GM); (CL)
| | - Chenjian Li
- Department of Neurology and Neurosciences, Weill Medical College of Cornell University, New York, New York, United States of America
- * E-mail: (GM); (CL)
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22
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Denton RM. Regulation of mitochondrial dehydrogenases by calcium ions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1309-16. [PMID: 19413950 DOI: 10.1016/j.bbabio.2009.01.005] [Citation(s) in RCA: 607] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Revised: 01/08/2009] [Accepted: 01/09/2009] [Indexed: 11/24/2022]
Abstract
Studies in Bristol in the 1960s and 1970s, led to the recognition that four mitochondrial dehydrogenases are activated by calcium ions. These are FAD-glycerol phosphate dehydrogenase, pyruvate dehydrogenase, NAD-isocitrate dehydrogenase and oxoglutarate dehydrogenase. FAD-glycerol phosphate dehydrogenase is located on the outer surface of the inner mitochondrial membrane and is influenced by changes in cytoplasmic calcium ion concentration. The other three enzymes are located within mitochondria and are regulated by changes in mitochondrial matrix calcium ion concentration. These and subsequent studies on purified enzymes, mitochondria and intact cell preparations have led to the widely accepted view that the activation of these enzymes is important in the stimulation of the respiratory chain and hence ATP supply under conditions of increased ATP demand in many stimulated mammalian cells. The effects of calcium ions on FAD-isocitrate dehydrogenase involve binding to an EF-hand binding motif within this enzyme but the binding sites involved in the effects of calcium ions on the three intramitochondrial dehydrogenases remain to be fully established. It is also emphasised in this article that these three dehydrogenases appear only to be regulated by calcium ions in vertebrates and that this raises some interesting and potentially important developmental issues.
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Affiliation(s)
- Richard M Denton
- Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk, Bristol, BS8 ITD, UK.
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23
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O'Donnell JM, Fields A, Xu X, Chowdhury SAK, Geenen DL, Bi J. Limited functional and metabolic improvements in hypertrophic and healthy rat heart overexpressing the skeletal muscle isoform of SERCA1 by adenoviral gene transfer in vivo. Am J Physiol Heart Circ Physiol 2008; 295:H2483-94. [PMID: 18952713 DOI: 10.1152/ajpheart.01023.2008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adenoviral gene transfer of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA)2a to the hypertrophic heart in vivo has been consistently reported to lead to enhanced myocardial contractility. It is unknown if the faster skeletal muscle isoform, SERCA1, expressed in the whole heart in early failure, leads to similar improvements and whether metabolic requirements are maintained during an adrenergic challenge. In this study, Ad.cmv.SERCA1 was delivered in vivo to aortic banded and sham-operated Sprague-Dawley rat hearts. The total SERCA content increased 34%. At 48-72 h posttransfer, echocardiograms were acquired, hearts were excised and retrograded perfused, and hemodynamics were measured parallel to NMR measures of the phosphocreatine (PCr)-to-ATP ratio (PCr/ATP) and energy substrate selection at basal and high workloads (isoproterenol). In the Langendorff mode, the rate-pressure product was enhanced 27% with SERCA1 in hypertrophic hearts and 10% in shams. The adrenergic response to isoproterenol was significantly potentiated in both groups with SERCA1. 31P NMR analysis of PCr/ATP revealed that the ratio remained low in the hypertrophic group with SERCA1 overexpression and was not further compromised with adrenergic challenge. 13C NMR analysis revealed fat and carbohydrate oxidation were unaffected at basal with SERCA1 expression; however, there was a shift from fats to carbohydrates at higher workloads with SERCA1 in both groups. Transport of NADH-reducing equivalents into the mitochondria via the alpha-ketoglutamate-malate transporter was not affected by either SERCA1 overexpression or adrenergic challenge in both groups. Echocardiograms revealed an important distinction between in vivo versus ex vivo data. In contrast to previous SERCA2a studies, the echocardiogram data revealed that SERCA1 expression compromised function (fractional shortening) in the hypertrophic group. Shams were unaffected. While our ex vivo findings support much of the earlier cardiomyocyte and transgenic data, the in vivo data challenge previous reports of improved cardiac function in heart failure models after SERCA intervention.
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Affiliation(s)
- J Michael O'Donnell
- Department of Physiology and Biophysics M/C 901 College of Medicine, University of Illinois, 835 S. Wolcott Ave., Chicago, IL 60612, USA.
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Matsuzaki S, Szweda LI. Inhibition of complex I by Ca2+ reduces electron transport activity and the rate of superoxide anion production in cardiac submitochondrial particles. Biochemistry 2007; 46:1350-7. [PMID: 17260964 DOI: 10.1021/bi0617916] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Declines in the rate of mitochondrial electron transport and subsequent increases in the half-life of reduced components of the electron transport chain can stimulate O2*- formation. We have previously shown that, in solubilized cardiac mitochondria, Ca2+ mediates reversible free radical-induced inhibition of complex I. In the study presented here, submitochondrial particles prepared from rat heart were utilized to determine the effects of Ca2+ on specific components of the respiratory chain and on the rates of electron transport and O2*- production. The results indicate that complex I is inactivated when submitochondrial particles are treated with Ca2+. Inactivation was specific to complex I with no alterations in the activities of other electron transport chain complexes. Complex I inactivation by Ca2+ resulted in the reduction of NADH-supported electron transport activity. In contrast to the majority of electron transport chain inhibitors, Ca2+ suppressed the rate of O2*- production. In addition, while inhibition of complex III stimulated O2*- production, Ca2+ reduced the relative rate of O2*- production, consistent with the magnitude of complex I inhibition. Evidence indicates that complex I is the primary source of O2*- released from this preparation of submitochondrial particles. Ca2+ therefore inhibits electron transport upstream of site(s) of free radical production. This may represent a means of limiting O2*- production by a compromised electron transport chain.
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Affiliation(s)
- Satoshi Matsuzaki
- Free Radical Biology and Aging Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
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25
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MacDonald PE, Joseph JW, Rorsman P. Glucose-sensing mechanisms in pancreatic beta-cells. Philos Trans R Soc Lond B Biol Sci 2006; 360:2211-25. [PMID: 16321791 PMCID: PMC1569593 DOI: 10.1098/rstb.2005.1762] [Citation(s) in RCA: 239] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The appropriate secretion of insulin from pancreatic beta-cells is critically important to the maintenance of energy homeostasis. The beta-cells must sense and respond suitably to postprandial increases of blood glucose, and perturbation of glucose-sensing in these cells can lead to hypoglycaemia or hyperglycaemias and ultimately diabetes. Here, we review beta-cell glucose-sensing with a particular focus on the regulation of cellular excitability and exocytosis. We examine in turn: (i) the generation of metabolic signalling molecules; (ii) the regulation of beta-cell membrane potential; and (iii) insulin granule dynamics and exocytosis. We further discuss the role of well known and putative candidate metabolic signals as regulators of insulin secretion.
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Affiliation(s)
- Patrick E MacDonald
- Duke University Medical Center Sarah W. Stedman Nutrition and Metabolism Center Durham, NC 27704, USA.
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Dunne MJ, Cosgrove KE, Shepherd RM, Aynsley-Green A, Lindley KJ. Hyperinsulinism in Infancy: From Basic Science to Clinical Disease. Physiol Rev 2004; 84:239-75. [PMID: 14715916 DOI: 10.1152/physrev.00022.2003] [Citation(s) in RCA: 185] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Dunne, Mark J., Karen E. Cosgrove, Ruth M. Shepherd, Albert Aynsley-Green, and Keith J. Lindley. Hyperinsulinism in Infancy: From Basic Science to Clinical Disease. Physiol Rev 84: 239–275, 2004; 10.1152/physrev.00022.2003.—Ion channelopathies have now been described in many well-characterized cell types including neurons, myocytes, epithelial cells, and endocrine cells. However, in only a few cases has the relationship between altered ion channel function, cell biology, and clinical disease been defined. Hyperinsulinism in infancy (HI) is a rare, potentially lethal condition of the newborn and early childhood. The causes of HI are varied and numerous, but in almost all cases they share a common target protein, the ATP-sensitive K+channel. From gene defects in ion channel subunits to defects in β-cell metabolism and anaplerosis, this review describes the relationship between pathogenesis and clinical medicine. Until recently, HI was generally considered an orphan disease, but as parallel defects in ion channels, enzymes, and metabolic pathways also give rise to diabetes and impaired insulin release, the HI paradigm has wider implications for more common disorders of the endocrine pancreas and the molecular physiology of ion transport.
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Affiliation(s)
- Mark J Dunne
- Research Division of Physiology and Pharmacology, The School of Biological Sciences, University of Manchester, Manchester, United Kingdom.
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Cherednichenko G, Zima AV, Feng W, Schaefer S, Blatter LA, Pessah IN. NADH oxidase activity of rat cardiac sarcoplasmic reticulum regulates calcium-induced calcium release. Circ Res 2003; 94:478-86. [PMID: 14699012 DOI: 10.1161/01.res.0000115554.65513.7c] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
NADH and Ca2+ have important regulatory functions in cardiomyocytes related to excitation-contraction coupling and ATP production. To elucidate elements of these functions, we examined the effect of NADH on sarcoplasmic reticulum (SR) Ca2+ release and the mechanisms of this regulation. Physiological concentrations of cytosolic NADH inhibited ryanodine receptor type 2 (RyR2)-mediated Ca2+-induced Ca2+ release (CICR) from SR membranes (IC50=120 micromol/L) and significantly lowered single channel open probability. In permeabilized single ventricular cardiomyocytes, NADH significantly inhibited the amplitude and frequency of spontaneous Ca2+ release. Blockers of electron transport prevented the inhibitory effect of NADH on CICR in isolated membranes and permeabilized cells, as well as on the activity of RyR2 channels reconstituted in lipid bilayer. An endogenous NADH oxidase activity from rat heart copurified with SR enriched with RyR2. A significant contribution by mitochondria was excluded as NADH oxidation by SR exhibited >9-fold higher catalytic activity (8.8 micromol/mg protein per minute) in the absence of exogenous mitochondrial complex I (ubiquinone) or complex III (cytochrome c) electron acceptors, but was inhibited by rotenone and pyridaben (IC50=2 to 3 nmol/L), antimycin A (IC50=13 nmol/L), and diphenyleneiodonium (IC50=28 micromol/L). Cardiac junctional SR treated with [3H](trifluoromethyl)diazirinyl-pyridaben specifically labeled a single 23-kDa PSST-like protein. These data indicate that NADH oxidation is tightly linked to, and essential for, negative regulation of the RyR2 complex and is a likely component of an important physiological negative-feedback mechanism coupling SR Ca2+ fluxes and mitochondrial energy production.
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Affiliation(s)
- Gennady Cherednichenko
- Department of Molecular Biosciences, Northern California Health Care System, University of California, Davis, Calif 95616, USA
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28
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Lasorsa FM, Pinton P, Palmieri L, Fiermonte G, Rizzuto R, Palmieri F. Recombinant expression of the Ca(2+)-sensitive aspartate/glutamate carrier increases mitochondrial ATP production in agonist-stimulated Chinese hamster ovary cells. J Biol Chem 2003; 278:38686-92. [PMID: 12851387 DOI: 10.1074/jbc.m304988200] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Ca(2+)-sensitive dehydrogenases of the mitochondrial matrix are, so far, the only known effectors to allow Ca2+ signals to couple the activation of plasma membrane receptors to the stimulation of aerobic metabolism. In this study, we demonstrate a novel mechanism, based on Ca(2+)-sensitive metabolite carriers of the inner membrane. We expressed in Chinese hamster ovary cells aralar1 and citrin, aspartate/glutamate exchangers that have Ca(2+)-binding sites in their sequence, and measured mitochondrial Ca2+ and ATP levels as well as cytosolic Ca2+ concentration with targeted recombinant probes. The increase in mitochondrial ATP levels caused by cell stimulation with Ca(2+)-mobilizing agonists was markedly larger in cells expressing aralar and citrin (but not truncated mutants lacking the Ca(2+)-binding site) than in control cells. Conversely, the cytosolic and the mitochondrial Ca2+ signals were the same in control cells and cells expressing the different aralar1 and citrin variants, thus ruling out an indirect effect through the Ca(2+)-sensitive dehydrogenases. Together, these data show that the decoding of Ca2+ signals in mitochondria depends on the coordinate activity of mitochondrial enzymes and carriers, which may thus represent useful pharmacological targets in this process of major pathophysiological interest.
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Affiliation(s)
- Francesco Massimo Lasorsa
- Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari and CNR Institute of Biomembranes and Bioenergetics, Via Orabona 4, 70125 Bari, Italy
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29
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Ward ML, Cooper PJ, Hanley PJ, Loiselle DS. Species-independent metabolic response to an increase of [Ca(2+)](i) in quiescent cardiac muscle. Clin Exp Pharmacol Physiol 2003; 30:586-9. [PMID: 12890184 DOI: 10.1046/j.1440-1681.2003.03877.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. The aim of the present investigation was to contrast the Ca2+ dependence of cardiac energy metabolism in two species with differential reliance on extracellular Ca2+ for excitation-contraction coupling. 2. We measured energy expenditure as the rate of oxygen consumption (Vo2) of isolated, Langendorff-perfused hearts of rats and guinea-pigs during KCl arrest. In parallel experiments, we indexed intracellular Ca2+ concentration ([Ca2+]i) of isolated right-ventricular trabeculae, using the Ca2+ fluorophore fura-2 and ratiometric spectrofluorometry. By varying extracellular Na+ concentration ([Na+]o), Vo2-[Na+]o and [Ca2+]i-[Na+]o relationships were constructed for each species. 3. Reduction of [Na+]o during K+ arrest caused pronounced species-dependent elevations of both Vo2 and [Ca2+]i. Despite the species dependence of both Vo2 and [Ca2+]i on [Na+]o, a single species-independent Vo2-[Ca2+]i relationship obtained. 4. We infer that elevation of the metabolic rate of the arrested heart above its basal value is determined primarily by [Ca2+]i and is not species dependent.
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Affiliation(s)
- Marie-Louise Ward
- Department of Physiology, Faculty of Medicine and Health Science and Bioengineering Institute, University of Auckland, Auckland, New Zealand.
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30
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Kadenbach B. Intrinsic and extrinsic uncoupling of oxidative phosphorylation. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1604:77-94. [PMID: 12765765 DOI: 10.1016/s0005-2728(03)00027-6] [Citation(s) in RCA: 362] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
This article reviews parameters of extrinsic uncoupling of oxidative phosphorylation (OxPhos) in mitochondria, based on induction of a proton leak across the inner membrane. The effects of classical uncouplers, fatty acids, uncoupling proteins (UCP1-UCP5) and thyroid hormones on the efficiency of OxPhos are described. Furthermore, the present knowledge on intrinsic uncoupling of cytochrome c oxidase (decrease of H(+)/e(-) stoichiometry=slip) is reviewed. Among the three proton pumps of the respiratory chain of mitochondria and bacteria, only cytochrome c oxidase is known to exhibit a slip of proton pumping. Intrinsic uncoupling was shown after chemical modification, by site-directed mutagenesis of the bacterial enzyme, at high membrane potential DeltaPsi, and in a tissue-specific manner to increase thermogenesis in heart and skeletal muscle by high ATP/ADP ratios, and in non-skeletal muscle tissues by palmitate. In addition, two mechanisms of respiratory control are described. The first occurs through the membrane potential DeltaPsi and maintains high DeltaPsi values (150-200 mV). The second occurs only in mitochondria, is suggested to keep DeltaPsi at low levels (100-150 mV) through the potential dependence of the ATP synthase and the allosteric ATP inhibition of cytochrome c oxidase at high ATP/ADP ratios, and is reversibly switched on by cAMP-dependent phosphorylation. Finally, the regulation of DeltaPsi and the production of reactive oxygen species (ROS) in mitochondria at high DeltaPsi values (150-200 mV) are discussed.
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Affiliation(s)
- Bernhard Kadenbach
- Fachbereich Chemie, Philipps-Universität, Hans-Meerwein-Strasse, D-35032 Marburg, Germany.
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31
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Lee B, Miles PD, Vargas L, Luan P, Glasco S, Kushnareva Y, Kornbrust ES, Grako KA, Wollheim CB, Maechler P, Olefsky JM, Anderson CM. Inhibition of mitochondrial Na+-Ca2+ exchanger increases mitochondrial metabolism and potentiates glucose-stimulated insulin secretion in rat pancreatic islets. Diabetes 2003; 52:965-73. [PMID: 12663468 DOI: 10.2337/diabetes.52.4.965] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The mitochondrial Na(+)-Ca(2+) exchanger (mNCE) mediates efflux of Ca(2+) from mitochondria in exchange for influx of Na(+). We show that inhibition of the mNCE enhances mitochondrial oxidative metabolism and increases glucose-stimulated insulin secretion in rat islets and INS-1 cells. The benzothiazepine CGP37157 inhibited mNCE activity in INS-1 cells (50% inhibition at IC(50) = 1.5 micro mol/l) and increased the glucose-induced rise in mitochondrial Ca(2+) ([Ca(2+)](m)) 2.1 times. Cellular ATP content was increased by 13% in INS-1 cells and by 49% in rat islets by CGP37157 (1 micro mol/l). Krebs cycle flux was also stimulated by CGP37157 when glucose was present. Insulin secretion was increased in a glucose-dependent manner by CGP37157 in both INS-1 cells and islets. In islets, CGP37157 increased insulin secretion dose dependently (half-maximal efficacy at EC(50) = 0.06 micro mol/l) at 8 mmol/l glucose and shifted the glucose dose response curve to the left. In perifused islets, mNCE inhibition had no effect on insulin secretion at 2.8 mmol/l glucose but increased insulin secretion by 46% at 11 mmol/l glucose. The effects of CGP37157 could not be attributed to interactions with the plasma membrane sodium calcium exchanger, L-type calcium channels, ATP-sensitive K(+) channels, or [Ca(2+)](m) uniporter. In hyperglycemic clamp studies of Wistar rats, CGP37157 increased plasma insulin and C-peptide levels only during the hyperglycemic phase of the study. These results illustrate the potential utility of agents that affect mitochondrial metabolism as novel insulin secretagogues.
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Affiliation(s)
- Bumsup Lee
- Division of Metabolic Diseases, MitoKor, San Diego, California 92121, USA
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Abstract
J The [Ca2+] regulation of contractile ATPase flux, Jp, in skeletal muscle was analysed by computation of the Response R(Jp) Ca2+ for a 10 Hz range of electrical stimulation frequencies. Results of our analysis of the kinetic controls in ATP free energy metabolism in a network model of contracting muscle (J.A.L. Jeneson, H.V. Westerhoff and M.J. Kushmerick (2000) Am. J Physiol. 279, C813-C832) formed the basis for the computations of R(Jp) Ca2+. We found that neural regulation of sustained force generation via simple [Ca2+]cyto frequency encoding in the network was robust for frequencies up to 2 Hz. Above 2 Hz, however, this regulation design broke down because of a shift in contractile ATPase flux control from the Ca2+-sensitive contractile filaments to mitochondria with low Ca2+ sensitivity. The role of glyco(geno)lytic ATP production at high contraction workloads is discussed in the context of this result.
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Affiliation(s)
- J A L Jeneson
- Department of Physiology, School of Veterinary Medicine, Utrecht University, NL
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33
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Brandes R, Bers DM. Simultaneous measurements of mitochondrial NADH and Ca(2+) during increased work in intact rat heart trabeculae. Biophys J 2002; 83:587-604. [PMID: 12124250 PMCID: PMC1302172 DOI: 10.1016/s0006-3495(02)75194-1] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The main goal of this study is to investigate the role of mitochondrial [Ca(2+)], [Ca(2+)](m), in the possible up-regulation of the NADH production rate during increased workload. Such up-regulation is necessary to support increased flux through the electron transport chain and increased ATP synthesis rates. Intact cardiac trabeculae were loaded with Rhod-2(AM), and [Ca(2+)](m) and mitochondrial [NADH] ([NADH](m)) were simultaneously measured during increased pacing frequency. It was found that 53% of Rhod-2 was localized in mitochondria. Increased pacing frequency caused a fast, followed by a slow rise of the Rhod-2 signal, which could be attributed to an abrupt increase in resting cytosolic [Ca(2+)], and a more gradual rise of [Ca(2+)](m), respectively. When the pacing frequency was increased from 0.25 to 2 Hz, the slow Rhod-2 component and the NADH signal increased by 18 and 11%, respectively. Based on a new calibration method, the 18% increase of the Rhod-2 signal was calculated to correspond to a 43% increase of [Ca(2+)](m). There was also a close temporal relationship between the rise (time constant approximately 25 s) and fall (time constant approximately 65 s) of [Ca(2+)](m) and [NADH](m) when the pacing frequency was increased and decreased, respectively, suggesting that increased workload and [Ca(2+)](c) cause increased [Ca(2+)](m) and consequently up-regulation of the NADH production rate.
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Affiliation(s)
- Rolf Brandes
- Novasite Pharmaceuticals, San Diego, California 92121, USA.
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Roche TE, Baker JC, Yan X, Hiromasa Y, Gong X, Peng T, Dong J, Turkan A, Kasten SA. Distinct regulatory properties of pyruvate dehydrogenase kinase and phosphatase isoforms. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2002; 70:33-75. [PMID: 11642366 DOI: 10.1016/s0079-6603(01)70013-x] [Citation(s) in RCA: 197] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The mammalian pyruvate dehydrogenase complex (PDC) plays central and strategic roles in the control of the use of glucose-linked substrates as sources of oxidative energy or as precursors in the biosynthesis of fatty acids. The activity of this mitochondrial complex is regulated by the continuous operation of competing pyruvate dehydrogenase kinase (PDK) and pyruvate dehydrogenase phosphatase (PDP) reactions. The resulting interconversion cycle determines the fraction of active (nonphosphorylated) pyruvate dehydrogenase (E1) component. Tissue-specific and metabolic state-specific control is achieved by the selective expression and distinct regulatory properties of at least four PDK isozymes and two PDP isozymes. The PDK isoforms are members of a family of serine kinases that are not structurally related to cytoplasmic Ser/Thr/Tyr kinases. The catalytic subunits of the PDP isoforms are Mg2+-dependent members of the phosphatase 2C family that has binuclear metal-binding sites within the active site. The dihydrolipoyl acetyltransferase (E2) and the dihydrolipoyl dehydrogenase-binding protein (E3BP) are multidomain proteins that form the oligomeric core of the complex. One or more of their three lipoyl domains (two in E2) selectively bind each PDK and PDP1. These adaptive interactions predominantly influence the catalytic efficiencies and effector control of these regulatory enzymes. When fatty acids are the preferred source of acetyl-CoA and NADH, feedback inactivation of PDC is accomplished by the activity of certain kinase isoforms being stimulated upon preferentially binding a lipoyl domain containing a reductively acetylated lipoyl group. PDC activity is increased in Ca2+-sensitive tissues by elevating PDP1 activity via the Ca2+-dependent binding of PDP1 to a lipoyl domain of E2. During starvation, the irrecoverable loss of glucose carbons is restricted by minimizing PDC activity due to high kinase activity that results from the overexpression of specific kinase isoforms. Overexpression of the same PDK isoforms deleteriously hinders glucose consumption in unregulated diabetes.
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Affiliation(s)
- T E Roche
- Department of Biochemistry, Kansas State University, Manhattan 66506-3702, USA
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Moller IM. PLANT MITOCHONDRIA AND OXIDATIVE STRESS: Electron Transport, NADPH Turnover, and Metabolism of Reactive Oxygen Species. ANNUAL REVIEW OF PLANT PHYSIOLOGY AND PLANT MOLECULAR BIOLOGY 2001; 52:561-591. [PMID: 11337409 DOI: 10.1146/annurev.arplant.52.1.561] [Citation(s) in RCA: 890] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The production of reactive oxygen species (ROS), such as O2- and H2O2, is an unavoidable consequence of aerobic metabolism. In plant cells the mitochondrial electron transport chain (ETC) is a major site of ROS production. In addition to complexes I-IV, the plant mitochondrial ETC contains a non-proton-pumping alternative oxidase as well as two rotenone-insensitive, non-proton-pumping NAD(P)H dehydrogenases on each side of the inner membrane: NDex on the outer surface and NDin on the inner surface. Because of their dependence on Ca2+, the two NDex may be active only when the plant cell is stressed. Complex I is the main enzyme oxidizing NADH under normal conditions and is also a major site of ROS production, together with complex III. The alternative oxidase and possibly NDin(NADH) function to limit mitochondrial ROS production by keeping the ETC relatively oxidized. Several enzymes are found in the matrix that, together with small antioxidants such as glutathione, help remove ROS. The antioxidants are kept in a reduced state by matrix NADPH produced by NADP-isocitrate dehydrogenase and non-proton-pumping transhydrogenase activities. When these defenses are overwhelmed, as occurs during both biotic and abiotic stress, the mitochondria are damaged by oxidative stress.
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Affiliation(s)
- Ian M Moller
- Department of Plant Physiology, Lund University, Lund, Box 117, S-221 00 Sweden;, Plant Biology and Biogeochemistry Department, Riso National Laboratory, Building 301, P.O. Box 49, DK-4000 Roskilde, Denmark; e-mail:
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Gunter TE, Buntinas L, Sparagna G, Eliseev R, Gunter K. Mitochondrial calcium transport: mechanisms and functions. Cell Calcium 2000; 28:285-96. [PMID: 11115368 DOI: 10.1054/ceca.2000.0168] [Citation(s) in RCA: 279] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Ca(2+)transport across the mitochondrial inner membrane is facilitated by transporters having four distinct sets of characteristics as well as through the Ca(2+)-induced mitochondrial permeability transition pore (PTP). There are two modes of inward transport, referred to as the Ca(2+)uniporter and the rapid mode or RaM. There are also two distinct mechanisms mediating outward transport, which are not associated with the PTP, referred to as the Na(+)-dependent and the Na(+)-independent Ca(2+)efflux mechanisms. Several important functions have been proposed for these mechanisms, including control of the metabolic rate for cellular energy (ATP) production, modulation of the amplitude and shape of cytosolic Ca(2+)transients, and induction of apoptosis through release of cytochrome c from the mitochondrial inter membrane space into the cytosolic space. The goals of this review are to survey the literature describing the characteristics of the mechanisms of mitochondrial Ca(2+)transport and their proposed physiological functions, emphasizing the more recent contributions, and to consider how the observed characteristics of the mitochondrial Ca(2+)transport mechanisms affect our understanding of their functions.
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Affiliation(s)
- T E Gunter
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
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38
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Abstract
Glucose-induced insulin secretion is pulsatile. Glucose metabolism generates oscillations in the ATP/ADP ratio which lead to opening and closing of ATP-sensitive K(+)-channels producing subsequent oscillations in membrane potential, cytoplasmic calcium and insulin release. Metabolic signals derived from glucose can also stimulate insulin release independent of their effects on ATP-sensitive K(+)-channels. The ATP/ADP ratio may mediate both ATP-sensitive K(+)-channel-dependent and -independent pathways of secretion. Glucose metabolism also results in an increase in long-chain acyl-CoA, which is proposed to act as an effector molecule in the beta -cell. Long-chain acyl-CoA has a variety of effects in the beta -cell that may effect insulin secretion including opening ATP-sensitive K(+)-channels, activating endoplasmic reticulum Ca(2+)-ATPases and stimulating classical protein kinase C activity. In addition to stimulating insulin release, nutrients also effect gene expression, protein synthesis and beta -cell proliferation. Gene expression is effected by nutrient induction of a variety of immediate early response genes. Glucose stimulates proinsulin biosynthesis both at the translational and transcriptional level. beta -cell proliferation, as a result of insulin-like growth factor and growth hormone mitogenic pathways, is also glucose dependent. Thus, many beta -cell functions in addition to secretion are controlled by nutrient metabolism.
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Affiliation(s)
- J T Deeney
- Obesity Research Center, Evans Department of Medicine, Boston Medical Center, Boston, MA 02118, USA
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39
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Abstract
The metabolic control of oxidative phosphorylation (OXPHOS) has attracted increasing attention in recent years, especially due to its importance for understanding the role of mitochondrial DNA mutations in human diseases and aging. Experiments on isolated mitochondria have indicated that a relatively small fraction of each of several components of the electron transport chain is sufficient to sustain a normal respiration rate. These experiments, however, may have not reflected the in vivo situation, due to the possible loss of essential metabolites during organelle isolation and the disruption of the normal interactions of mitochondria with the cytoskeleton, which may be important for the channeling of respiratory substrate to the organelles. To obtain direct evidence on this question, in particular, as concerns the in vivo control of respiration by cytochrome c oxidase (COX), we have developed an approach for measuring COX activity in intact cells, by means of cyanide titration, either as an isolated step or as a respiratory chain-integrated step. The method has been applied to a variety of human cell types, including wild-type and mtDNA mutation-carrying cells, several tumor-derived semidifferentiated cell lines, as well as specialized cells removed from the organism. The results obtained strongly support the following conclusions: (i) the in vivo control of respiration by COX is much tighter than has been generally assumed on the basis of experiments carried out on isolated mitochondria; (ii) COX thresholds depend on the respiratory fluxes under which they are measured; and (iii) measurements of relative enzyme capacities are needed for understanding the role of mitochondrial respiratory complexes in human physiopathology.
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Affiliation(s)
- G Villani
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA
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40
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Opuni K, Reeves JP. Feedback inhibition of sodium/calcium exchange by mitochondrial calcium accumulation. J Biol Chem 2000; 275:21549-54. [PMID: 10801871 DOI: 10.1074/jbc.m003158200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chinese hamster ovary cells expressing the bovine cardiac Na(+)/Ca(2+) exchanger were subjected to two periods of 5 and 3 min, respectively, during which the extracellular Na(+) concentration ([Na(+)](o)) was reduced to 20 mm; these intervals were separated by a 5-min recovery period at 140 mm Na(+)(o). The cytosolic Ca(2+) concentration ([Ca(2+)](i)) increased during both intervals due to Na(+)-dependent Ca(2+) influx by the exchanger. However, the peak rise in [Ca(2+)](i) during the second interval was only 26% of the first. The reduced rise in [Ca(2+)](i) was due to an inhibition of Na(+)/Ca(2+) exchange activity rather than increased Ca(2+) sequestration since the influx of Ba(2+), which is not sequestered by internal organelles, was also inhibited by a prior interval of Ca(2+) influx. Mitochondria accumulated Ca(2+) during the first interval of reduced [Na(+)](o), as determined by an increase in fluorescence of the Ca(2+)-indicating dye rhod-2, which preferentially labels mitochondria. Agents that blocked mitochondrial Ca(2+) accumulation (uncouplers, nocodazole) eliminated the observed inhibition of exchange activity during the second period of low [Na(+)](o). Conversely, diltiazem, an inhibitor of the mitochondrial Na(+)/Ca(2+) exchanger, increased mitochondrial Ca(2+) accumulation and also increased the inhibition of exchange activity. We conclude that Na(+)/Ca(2+) exchange activity is regulated by a feedback inhibition process linked to mitochondrial Ca(2+) accumulation.
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Affiliation(s)
- K Opuni
- Department of Pharmacology and Physiology, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Graduate School of Biomedical Sciences, Newark, New Jersey 07103, USA
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Szalai G, Csordás G, Hantash BM, Thomas AP, Hajnóczky G. Calcium signal transmission between ryanodine receptors and mitochondria. J Biol Chem 2000; 275:15305-13. [PMID: 10809765 DOI: 10.1074/jbc.275.20.15305] [Citation(s) in RCA: 181] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Control of energy metabolism by increases of mitochondrial matrix [Ca(2+)] ([Ca(2+)](m)) may represent a fundamental mechanism to meet the ATP demand imposed by heart contractions, but the machinery underlying propagation of [Ca(2+)] signals from ryanodine receptor Ca(2+) release channels (RyR) to the mitochondria remains elusive. Using permeabilized cardiac (H9c2) cells we investigated the cytosolic [Ca(2+)] ([Ca(2+)](c)) and [Ca(2+)](m) signals elicited by activation of RyR. Caffeine, Ca(2+), and ryanodine evoked [Ca(2+)](c) spikes that often appeared as frequency-modulated [Ca(2+)](c) oscillations in these permeabilized cells. Rapid increases in [Ca(2+)](m) and activation of the Ca(2+)-sensitive mitochondrial dehydrogenases were synchronized to the rising phase of the [Ca(2+)](c) spikes. The RyR-mediated elevations of global [Ca(2+)](c) were in the submicromolar range, but the rate of [Ca(2+)](m) increases was as large as it was in the presence of 30 microm global [Ca(2+)](c). Furthermore, RyR-dependent increases of [Ca(2+)](m) were relatively insensitive to buffering of [Ca(2+)](c) by EGTA. Therefore, RyR-driven rises of [Ca(2+)](m) appear to result from large and rapid increases of perimitochondrial [Ca(2+)]. The falling phase of [Ca(2+)](c) spikes was followed by a rapid decay of [Ca(2+)](m). CGP37157 slowed down relaxation of [Ca(2+)](m) spikes, whereas cyclosporin A had no effect, suggesting that activation of the mitochondrial Ca(2+) exchangers accounts for rapid reversal of the [Ca(2+)](m) response with little contribution from the permeability transition pore. Thus, rapid activation of Ca(2+) uptake sites and Ca(2+) exchangers evoked by RyR-mediated local [Ca(2+)](c) signals allow mitochondria to respond rapidly to single [Ca(2+)](c) spikes in cardiac cells.
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Affiliation(s)
- G Szalai
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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Griffiths EJ, Ocampo CJ, Savage JS, Stern MD, Silverman HS. Protective effects of low and high doses of cyclosporin A against reoxygenation injury in isolated rat cardiomyocytes are associated with differential effects on mitochondrial calcium levels. Cell Calcium 2000; 27:87-95. [PMID: 10756975 DOI: 10.1054/ceca.1999.0094] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this study we aimed to determine the concentration range of cyclosporin A (CsA) which was effective in protecting against reoxygenation injury in isolated cardiomyocytes, and its effects on intramitochondrial free calcium levels ([Ca2+]m). We also determined whether a high [CsA] had any deleterious effect on normal myocyte function. Isolated adult rat ventricular myocytes were placed in a chamber on the stage of a fluorescence microscope for induction of hypoxia. [Ca2+]m was determined from indo-1/am loaded cells where the cytosolic fluorescence signal had been quenched by superfusion with Mn2+. Cell length was measured using an edge-tracking device. Upon induction of hypoxia, control cells underwent rigor-contracture in 37 +/- 1 min (n = 99) (T1); CsA had no effect on T1. The percentage of control cells which recovered upon reoxygenation depended on the time spent in rigor (T2). With a T2 of 21-30 min, only 36% of control cells recovered compared with 90% and 78% of cells treated with 0.2 microM and 1 microM CsA respectively. After 40 min in rigor, [Ca2+]m was 280 +/- 60 nM in control-recovered cells (50% of cells) and 543 +/- 172 nM and 153 +/- 26 nM in cells treated with 0.2 and 1 microM CsA, respectively (all CsA treated cells recovered). In normoxic studies, CsA had no effect on cell contractility or [Ca2+]m upon rapid pacing, even in presence of an elevated external [Ca2+]. In conclusion, both low and high [CsA] protected against reoxygenation injury to cardiomyocytes despite having opposing effects on [Ca2+]m, suggesting more than one mechanism of action. CsA had no effect on either cell contractility or [Ca2+]m in normoxic cells.
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Affiliation(s)
- E J Griffiths
- Division of Cardiology, Johns Hopkins University Hospital, Baltimore, MD, USA.
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43
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Ockaili R, Emani VR, Okubo S, Brown M, Krottapalli K, Kukreja RC. Opening of mitochondrial KATP channel induces early and delayed cardioprotective effect: role of nitric oxide. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H2425-34. [PMID: 10600865 DOI: 10.1152/ajpheart.1999.277.6.h2425] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Opening of mitochondrial ATP-sensitive (mitoKATP) channel with diazoxide induces an early phase (EP) of cardioprotection. It is unknown whether diazoxide also induces a delayed phase (DP) of cardioprotection. Because nitric oxide (NO) modulates ATP sensitivity of the KATP channel, we hypothesized that NO may play a role in diazoxide-induced cardioprotection. Diazoxide (1 mg/kg) was administered either 30 min (for EP) or 24 h (DP) before 30 min of lethal ischemia. Blockers of mitoK(ATP) channel [5-hydroxydecanoate (5-HD)] or NO synthase [N(G)-nitro-L-arginine methyl ester (L-NAME)] were given 10 min before ischemia-reperfusion performed by 30 min of left anterior descending coronary artery occlusion and 3 h of reperfusion. A risk area (RA) was demarcated by Evans blue dye, and infarct size (IS) was measured by tetrazolium staining. Diazoxide caused a decrease in IS (%RA) from 27.8 +/- 4.2% in the vehicle group to 12.9 +/- 1.2% during EP and from 30.4 +/- 4. 2% in vehicle-treated rabbits to 19.6 +/- 2.4% during DP (P < 0.05). IS increased to 31.3 +/- 1.1% and 27.9 +/- 1.0% (EP) and 29.9 +/- 2. 3% and 35.1 +/- 1.8% (DP) with 5-HD and L-NAME, respectively (P < 0. 05). 5-HD and L-NAME caused no proischemic effect in controls. Diazoxide induced both early and delayed anti-ischemic effects via opening of mitoK(ATP) channels, which was NO dependent.
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Affiliation(s)
- R Ockaili
- Division of Cardiology, Department of Medicine, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia 23298, USA
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44
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Abstract
This article reviews the involvement of the mitochondrial permeability transition pore in necrotic and apoptotic cell death. The pore is formed from a complex of the voltage-dependent anion channel (VDAC), the adenine nucleotide translocase and cyclophilin-D (CyP-D) at contact sites between the mitochondrial outer and inner membranes. In vitro, under pseudopathological conditions of oxidative stress, relatively high Ca2+ and low ATP, the complex flickers into an open-pore state allowing free diffusion of low-Mr solutes across the inner membrane. These conditions correspond to those that unfold during tissue ischaemia and reperfusion, suggesting that pore opening may be an important factor in the pathogenesis of necrotic cell death following ischaemia/reperfusion. Evidence that the pore does open during ischaemia/reperfusion is discussed. There are also strong indications that the VDAC-adenine nucleotide translocase-CyP-D complex can recruit a number of other proteins, including Bax, and that the complex is utilized in some capacity during apoptosis. The apoptotic pathway is amplified by the release of apoptogenic proteins from the mitochondrial intermembrane space, including cytochrome c, apoptosis-inducing factor and some procaspases. Current evidence that the pore complex is involved in outer-membrane rupture and release of these proteins during programmed cell death is reviewed, along with indications that transient pore opening may provoke 'accidental' apoptosis.
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O'Donnell JM, White LT, Lewandowski ED. Mitochondrial transporter responsiveness and metabolic flux homeostasis in postischemic hearts. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H866-73. [PMID: 10484405 DOI: 10.1152/ajpheart.1999.277.3.h866] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The transport of metabolites between mitochondria and cytosol via the alpha-ketoglutarate-malate carrier serves to balance flux between the two spans of the tricarboxylic acid (TCA) cycle but is reduced in stunned myocardium. To examine the mechanism for reduced transporter activity, we followed the postischemic response of metabolite influx/efflux from mitochondria to stimulation of the malate-aspartate (MA) shuttle. Isolated rabbit hearts were either perfused with 2.5 mM [2-13C]acetate (n = 7) or similarly reperfused (n = 5) after 10-min ischemia. In other hearts, the MA shuttle was stimulated with a high cytosolic redox state (NADH) induced by 2.5 mM lactate in normal (n = 6) or reperfused hearts (n = 7). In normal hearts, the MA shuttle response accelerated transport from 8.3 +/- 3.4 to 16.2 +/- 5.0 micromol. min(-1). g dry wt(-1). Although transport was reduced in stunned hearts, the MA shuttle was responsive to cytosolic NADH load, increasing transport from 3.4 +/- 1.0 to 9.8 +/- 3.7 micromol. min(-1). g dry wt(-1). Therefore, metabolite exchange remains intact in stunned myocardium but responds to changes in TCA cycle flux regulation.
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Affiliation(s)
- J M O'Donnell
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129, USA
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Abstract
We have previously shown that increased cardiac work initially caused a rapid Ca(2+)-independent fall of mitochondrial [NADH] ([NADH](m)) to a minimum level, and this was followed by a slow Ca(2+)-dependent recovery toward control level (Brandes and Bers, Biophys. J. 71:1024-1035, 1996; Brandes and Bers, Circ. Res. 80:82-87, 1997). The purpose of this study is to improve our understanding of the factors that control [NADH](m) during increased work. [NADH](m) was monitored using fluorescence spectroscopy in intact rat trabeculae isolated from the right ventricular wall. Work was increased by increasing sarcomere length, pacing frequency, external [Ca(2+)], or by decreased temperature. The results were: 1) The initial fall of [NADH](m) during increased pacing frequency depends independently on increased myofilament work and on increased Ca(2+)-transport ATPase activity. 2) The [NADH](m) recovery process depends on average cytosolic [Ca(2+)] (Av[Ca(2+)](c)), but not on absolute work level. 3) The initial fall of [NADH](m) and the [NADH](m) recovery are similar whether increased work is associated with low frequency and high Ca(2+)-transient amplitude or vice versa (at the same myofilament work level and Av[Ca(2+)](c)). 4) The mechanisms associated with the smaller fall and recovery of [NADH](m) at 37 degrees C versus 27 degrees C, may be explained by lowered Av[Ca(2+)](c) and myofilament work. The NADH control mechanisms that operate at lower temperature are thus qualitatively similar at more physiological temperatures.
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Affiliation(s)
- R Brandes
- Department of Physiology, Loyola University, Chicago School of Medicine, 2160 South First Avenue, Maywood, Illinois 60153 USA.
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Wang Y, Ashraf M. Role of protein kinase C in mitochondrial KATP channel-mediated protection against Ca2+ overload injury in rat myocardium. Circ Res 1999; 84:1156-65. [PMID: 10347090 DOI: 10.1161/01.res.84.10.1156] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Growing evidence exists that ATP-sensitive mitochondrial potassium channels (MitoKATP channel) are a major contributor to the cardiac protection against ischemia. Given the importance of mitochondria in the cardiac cell, we tested whether the potent and specific opener of the MitoKATP channel diazoxide attenuates the lethal injury associated with Ca2+overload. The specific aims of this study were to test whether protection by diazoxide is mediated by MitoKATP channels; whether diazoxide mimics the effects of Ca2+ preconditioning; and whether diazoxide reduces Ca2+ paradox (PD) injury via protein kinase C (PKC) signaling pathways. Langendorff-perfused rat hearts were subjected to the Ca2+ PD (10 minutes of Ca2+ depletion followed by 10 minutes of Ca2+ repletion). The effects of the MitoKATP channel and other interventions on functional, biochemical, and pathological changes in hearts subjected to Ca2+ PD were assessed. In hearts treated with 80 micromol/L diazoxide, left ventricular end-diastolic pressure and coronary flow were significantly preserved after Ca2+ PD; peak lactate dehydrogenase release was also significantly decreased, although ATP content was less depleted. The cellular structures were well preserved, including mitochondria and intercalated disks in diazoxide-treated hearts compared with nontreated Ca2+ PD hearts. The salutary effects of diazoxide on the Ca2+ PD injury were similar to those in hearts that underwent Ca2+ preconditioning or pretreatment with phorbol 12-myristate 13-acetate before Ca2+ PD. The addition of sodium 5-hydroxydecanoate, a specific MitoKATP channel inhibitor, or chelerythrine chloride, a PKC inhibitor, during diazoxide pretreatment completely abolished the beneficial effects of diazoxide on the Ca2+ PD. Blockade of Ca2+ entry during diazoxide treatment by inhibiting L-type Ca2+ channel with verapamil or nifedipine also completely reversed the beneficial effects of diazoxide on the Ca2+ PD. PKC-delta was translocated to the mitochondria, intercalated disks, and nuclei of myocytes in diazoxide-pretreated hearts, and PKC-alpha and PKC-epsilon were translocated to sarcolemma and intercalated disks, respectively. This study suggests that the effect of the MitoKATP channel is mediated by PKC-mediated signaling pathway.
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Affiliation(s)
- Y Wang
- Department of Pathology and Laboratory Medicine, University of Cincinnati Medical Center, Cincinnati, Ohio 45267-0529, USA
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Drummond RM, Tuft RA. Release of Ca2+ from the sarcoplasmic reticulum increases mitochondrial [Ca2+] in rat pulmonary artery smooth muscle cells. J Physiol 1999; 516 ( Pt 1):139-47. [PMID: 10066929 PMCID: PMC2269219 DOI: 10.1111/j.1469-7793.1999.139aa.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
1. The Ca2+-sensitive fluorescent indicator rhod-2 was used to measure mitochondrial [Ca2+] ([Ca2+]m) in single smooth muscle cells from the rat pulmonary artery, while simultaneously monitoring cytosolic [Ca2+] ([Ca2+]i) with fura-2. 2. Application of caffeine produced an increase in [Ca2+]i and also increased [Ca2+]m. The increase in [Ca2+]m occurred after the increase in [Ca2+]i, and remained elevated for a considerable time after [Ca2+]i had returned to resting values. 3. The protonophore carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP), which causes the mitochondrial membrane potential to collapse, markedly attenuated the increase in [Ca2+]m following caffeine application and also increased the half-time for recovery of [Ca2+]i to resting values. 4. Activation of purinoceptors with ATP also produced increases in both [Ca2+]i and [Ca2+]m in these smooth muscle cells. In some cells, oscillations in [Ca2+]i were observed during ATP application, which produced corresponding oscillations in [Ca2+]m and membrane currents. 5. This study provides direct evidence that Ca2+ release from the sarcoplasmic reticulum, either through ryanodine or inositol 1,4, 5-trisphosphate (InsP3) receptors, increases both cytosolic and mitochondrial [Ca2+] in smooth muscle cells. These results have potential implications both for the role of mitochondria in Ca2+ regulation in smooth muscle, and for understanding how cellular metabolism is regulated.
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Affiliation(s)
- R M Drummond
- Department of Physiology, Biomedical Imaging Group, University of Massachusetts Medical Center, Worcester, MA 01605, USA.
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Chakraborti T, Das S, Mondal M, Roychoudhury S, Chakraborti S. Oxidant, mitochondria and calcium: an overview. Cell Signal 1999; 11:77-85. [PMID: 10048784 DOI: 10.1016/s0898-6568(98)00025-4] [Citation(s) in RCA: 211] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mitochondria are active in the continuous generation of reactive oxygen species (ROS), (e.g., superoxide), thereby favouring a situation of mitochondrial oxidative stress. Under oxidative stress--for example, ischaemia-reoxygenation injury to cells--mitochondria form superoxide, which in turn is converted to hydrogen peroxide and the potent reactive species, hydroxyl radical. Alternatively, mitochondrial superoxide may react with nitric oxide to form potent oxidant peroxynitrite and as a consequence, mitochondrial function is altered. An increase in the release of calcium from mitochondria by oxidants stimulates calcium-dependent enzymes such as calcium-dependent proteases, nucleases, and phospholipases, which subsequently trigger apoptosis of the cells. In principle, calcium can leave mitochondria by different ways: by non-specific leakage through the inner membrane by "pore formation," by changes in the membrane lipid phase, by reversal of the uniport influx carrier, by the specific calcium/hydrogen (or sodium) antiport system, by channel-mediated release pathways, or by a combination of two or more of these pathways. Additionally, the release of calcium from mitochondria can also occur either by oxidation of internal nicotinamide adenine nucleotides to ADP ribose and nicotinamide or by oxidation of thiols in membrane proteins. Once calcium efflux has been triggered, a series of common pathways of apoptosis are initiated, each of which may be sufficient to destroy the cell. Apoptosis requires the active participation of cellular components, and several genes have been suggested to control apoptosis. The proto-oncogene bcl-2 suppresses apoptosis through mitochondrial effects. Overexpression of bcl-2 in the mitochondrial membrane inhibits calcium efflux, but the underlying mechanisms are not clearly known. Further studies are needed to explore the nature of the apoptosis-inducing pathways, the precise mechanisms of calcium efflux, the molecular partners of bcl-2 oncoproteins at the level of the outer-inner membrane contact sites, the molecular biology of the apoptosis-inducing factor formation and release, and the essential molecular targets of apoptosis-inducing proteases. Clarification of these issues might facilitate the understanding of mitochondrial response on cellular calcium dynamics under oxidant stress.
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Affiliation(s)
- T Chakraborti
- Department of Biochemistry and Biophysics, University of Kalyani, West Bengal, India
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50
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Pepe S, Tsuchiya N, Lakatta EG, Hansford RG. PUFA and aging modulate cardiac mitochondrial membrane lipid composition and Ca2+ activation of PDH. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:H149-58. [PMID: 9887028 DOI: 10.1152/ajpheart.1999.276.1.h149] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aberrations in cell Ca2+ homeostasis have been known to parallel both changes in membrane lipid composition and aging. Previous work has shown that the lowered efficiency of work performance, which occurs in isolated hearts from rats fed a diet rich in n-6 polyunsaturated fatty acids (PUFA), relative to those fed n-3 PUFA, could be raised by mitochondrial (Mito) Ca2+ transport inhibition. We tested whether, after Ca2+-dependent stress, the Ca2+-dependent activation of pyruvate dehydrogenase (PDHA/PDHTotal) and Mito Ca2+ cycling could be manipulated by varying the ratio of n-3 to n-6 PUFA in Mito membranes in young (6 mo) and aged (24 mo) isolated rat hearts treated to n-3 or n-6 PUFA-rich diet. Inotropic stimulation by 1 microM norepinephrine (NE) of 24-mo n-6 PUFA-rich hearts elevated total Mito Ca2+ content 38% more than in 6-mo hearts (P < 0. 05). However, both the NE-induced rise in Mito Ca2+ and the difference in response between 6- and 24-mo hearts were partially abolished by n-3 PUFA treatment. NE increased the fractional activation of PDH by 44% above control levels in the 6-mo group compared with 49% in the 24-mo group after n-6 PUFA diet. However, NE stimulation of PDHA was attenuated by n-3 PUFA diet, attaining values only 29 and 23% above control levels in 6- and 24-mo mitochondria, respectively (P < 0.05). Global ischemia and reperfusion (I/R) in n-6 PUFA hearts gave rise to higher levels of total Mito Ca2+ concentration (P < 0.0001) and PDHA (P < 0.0001) compared with n-3 PUFA. Ruthenium red (3.4 microM) abolished the effects of I/R in all groups. With aging, heart Mito membrane phosphatidylcholine was increased after n-6 PUFA-rich diet (by approximately 15%, P < 0.05), whereas cardiolipin and n-3 PUFA content were diminished by 31% (P < 0.05) and 73% (P < 0.05), respectively. These effects were prevented by n-3 PUFA-rich diet. The present study, by directly manipulating the cardiac Mito membrane n-3-to-n-6 PUFA ratio, shows that the activation of Ca2+-dependent PDH can be augmented when the n-3-to-n-6 PUFA ratio is low (n-6 PUFA-rich diet; 24-mo hearts) or attenuated when this ratio is relatively high (n-3 PUFA-rich diet). We propose that one of the consequences of dietary-induced manipulation of membrane phospholipids and PUFAs may be the altered flux of Ca2+ across the Mito membrane and thus altered intramitochondrial Ca2+-dependent processes.
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Affiliation(s)
- S Pepe
- Laboratory of Cardiovascular Science, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA
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