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Ghazal N, Kwong JQ. Analyzing Mitochondrial Calcium Influx in Isolated Mitochondria. Methods Mol Biol 2025; 2861:155-164. [PMID: 39395104 DOI: 10.1007/978-1-0716-4164-4_12] [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] [Indexed: 10/14/2024]
Abstract
Mitochondria play a crucial role in Ca2+ signaling and homeostasis and can contribute to shaping the cytosolic Ca2+ landscape as well as regulate a variety of pathways including energy production and cell death. Dysregulation of mitochondrial Ca2+ homeostasis promotes pathologies including neurodegenerative diseases, cardiovascular disorders, and metabolic syndromes. The significance of mitochondria to Ca2+ signaling and regulation underscores the value of methods to assess mitochondrial Ca2+ import. Here we present a plate reader-based method using the Ca2+-sensitive fluorescent probe calcium green-5 N to measure mitochondrial Ca2+ import in isolated cardiac mitochondria. This technique can be expanded to measure Ca2+ uptake in mitochondria isolated from other tissue types and from cultured cells.
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Affiliation(s)
- Nasab Ghazal
- Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA, USA
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine, and Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Jennifer Q Kwong
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine, and Children's Healthcare of Atlanta, Atlanta, GA, USA.
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA.
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2
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Balderas E, Lee SHJ, Rai NK, Mollinedo DM, Duron HE, Chaudhuri D. Mitochondrial Calcium Regulation of Cardiac Metabolism in Health and Disease. Physiology (Bethesda) 2024; 39:0. [PMID: 38713090 PMCID: PMC11460536 DOI: 10.1152/physiol.00014.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 05/02/2024] [Accepted: 05/02/2024] [Indexed: 05/08/2024] Open
Abstract
Oxidative phosphorylation is regulated by mitochondrial calcium (Ca2+) in health and disease. In physiological states, Ca2+ enters via the mitochondrial Ca2+ uniporter and rapidly enhances NADH and ATP production. However, maintaining Ca2+ homeostasis is critical: insufficient Ca2+ impairs stress adaptation, and Ca2+ overload can trigger cell death. In this review, we delve into recent insights further defining the relationship between mitochondrial Ca2+ dynamics and oxidative phosphorylation. Our focus is on how such regulation affects cardiac function in health and disease, including heart failure, ischemia-reperfusion, arrhythmias, catecholaminergic polymorphic ventricular tachycardia, mitochondrial cardiomyopathies, Barth syndrome, and Friedreich's ataxia. Several themes emerge from recent data. First, mitochondrial Ca2+ regulation is critical for fuel substrate selection, metabolite import, and matching of ATP supply to demand. Second, mitochondrial Ca2+ regulates both the production and response to reactive oxygen species (ROS), and the balance between its pro- and antioxidant effects is key to how it contributes to physiological and pathological states. Third, Ca2+ exerts localized effects on the electron transport chain (ETC), not through traditional allosteric mechanisms but rather indirectly. These effects hinge on specific transporters, such as the uniporter or the Na+/Ca2+ exchanger, and may not be noticeable acutely, contributing differently to phenotypes depending on whether Ca2+ transporters are acutely or chronically modified. Perturbations in these novel relationships during disease states may either serve as compensatory mechanisms or exacerbate impairments in oxidative phosphorylation. Consequently, targeting mitochondrial Ca2+ holds promise as a therapeutic strategy for a variety of cardiac diseases characterized by contractile failure or arrhythmias.
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Affiliation(s)
- Enrique Balderas
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Sandra H J Lee
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Neeraj K Rai
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - David M Mollinedo
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Hannah E Duron
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Dipayan Chaudhuri
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
- Division of Cardiovascular Medicine, Department of Internal Medicine, Biochemistry, Biomedical Engineering, University of Utah, Salt Lake City, Utah, United States
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3
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Nasuhidehnavi A, Zarzycka W, Górecki I, Chiao YA, Lee CF. Emerging interactions between mitochondria and NAD + metabolism in cardiometabolic diseases. Trends Endocrinol Metab 2024:S1043-2760(24)00191-7. [PMID: 39198117 DOI: 10.1016/j.tem.2024.07.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 07/12/2024] [Accepted: 07/15/2024] [Indexed: 09/01/2024]
Abstract
Nicotinamide adenine dinucleotide (NAD+) is an essential coenzyme for redox reactions and regulates cellular catabolic pathways. An intertwined relationship exists between NAD+ and mitochondria, with consequences for mitochondrial function. Dysregulation in NAD+ homeostasis can lead to impaired energetics and increased oxidative stress, contributing to the pathogenesis of cardiometabolic diseases. In this review, we explore how disruptions in NAD+ homeostasis impact mitochondrial function in various cardiometabolic diseases. We discuss emerging studies demonstrating that enhancing NAD+ synthesis or inhibiting its consumption can ameliorate complications of this family of pathological conditions. Additionally, we highlight the potential role and therapeutic promise of mitochondrial NAD+ transporters in regulating cellular and mitochondrial NAD+ homeostasis.
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Affiliation(s)
- Azadeh Nasuhidehnavi
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Binghamton University, Binghamton, NY 13790, USA
| | - Weronika Zarzycka
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Ignacy Górecki
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Ying Ann Chiao
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Chi Fung Lee
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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Cherpaz M, Meugnier E, Seillier G, Pozzi M, Pierrard R, Leboube S, Farhat F, Vola M, Obadia JF, Amaz C, Chalabreysse L, May C, Chanon S, Brun C, Givre L, Bidaux G, Mewton N, Derumeaux G, Bergerot C, Paillard M, Thibault H. Myocardial transcriptomic analysis of diabetic patients with aortic stenosis: key role for mitochondrial calcium signaling. Cardiovasc Diabetol 2024; 23:239. [PMID: 38978010 PMCID: PMC11232229 DOI: 10.1186/s12933-024-02329-5] [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: 03/15/2024] [Accepted: 06/19/2024] [Indexed: 07/10/2024] Open
Abstract
BACKGROUND Type 2 diabetes (T2D) is a frequent comorbidity encountered in patients with severe aortic stenosis (AS), leading to an adverse left ventricular (LV) remodeling and dysfunction. Metabolic alterations have been suggested as contributors of the deleterious effect of T2D on LV remodeling and function in patients with severe AS, but so far, the underlying mechanisms remain unclear. Mitochondria play a central role in the regulation of cardiac energy metabolism. OBJECTIVES We aimed to explore the mitochondrial alterations associated with the deleterious effect of T2D on LV remodeling and function in patients with AS, preserved ejection fraction, and no additional heart disease. METHODS We combined an in-depth clinical, biological and echocardiography phenotype of patients with severe AS, with (n = 34) or without (n = 50) T2D, referred for a valve replacement, with transcriptomic and histological analyses of an intra-operative myocardial LV biopsy. RESULTS T2D patients had similar AS severity but displayed worse cardiac remodeling, systolic and diastolic function than non-diabetics. RNAseq analysis identified 1029 significantly differentially expressed genes. Functional enrichment analysis revealed several T2D-specific upregulated pathways despite comorbidity adjustment, gathering regulation of inflammation, extracellular matrix organization, endothelial function/angiogenesis, and adaptation to cardiac hypertrophy. Downregulated gene sets independently associated with T2D were related to mitochondrial respiratory chain organization/function and mitochondrial organization. Generation of causal networks suggested a reduced Ca2+ signaling up to the mitochondria, with the measured gene remodeling of the mitochondrial Ca2+ uniporter in favor of enhanced uptake. Histological analyses supported a greater cardiomyocyte hypertrophy and a decreased proximity between the mitochondrial VDAC porin and the reticular IP3-receptor in T2D. CONCLUSIONS Our data support a crucial role for mitochondrial Ca2+ signaling in T2D-induced cardiac dysfunction in severe AS patients, from a structural reticulum-mitochondria Ca2+ uncoupling to a mitochondrial gene remodeling. Thus, our findings open a new therapeutic avenue to be tested in animal models and further human cardiac biopsies in order to propose new treatments for T2D patients suffering from AS. TRIAL REGISTRATION URL: https://www. CLINICALTRIALS gov ; Unique Identifier: NCT01862237.
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MESH Headings
- Humans
- Aortic Valve Stenosis/metabolism
- Aortic Valve Stenosis/genetics
- Aortic Valve Stenosis/physiopathology
- Aortic Valve Stenosis/diagnostic imaging
- Aortic Valve Stenosis/surgery
- Aortic Valve Stenosis/pathology
- Male
- Mitochondria, Heart/metabolism
- Mitochondria, Heart/pathology
- Female
- Aged
- Ventricular Remodeling
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/complications
- Calcium Signaling
- Ventricular Function, Left
- Gene Expression Profiling
- Transcriptome
- Severity of Illness Index
- Middle Aged
- Aged, 80 and over
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Dysfunction, Left/genetics
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/diagnostic imaging
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Affiliation(s)
- Maelle Cherpaz
- Laboratoire CarMeN - IRIS Team, INSERM, INRA, Université Claude Bernard Lyon-1, Univ-Lyon, 69500, Bron, France
- Centre d'investigation Clinique, Hospices Civils de Lyon, 69500, Bron, France
| | - Emmanuelle Meugnier
- Laboratoire CarMeN - IRIS Team, INSERM, INRA, Université Claude Bernard Lyon-1, Univ-Lyon, 69500, Bron, France
| | - Gaultier Seillier
- Explorations Fonctionnelles Cardiovasculaires, Hospices Civils de Lyon, 69500, Bron, France
| | - Matteo Pozzi
- Chirurgie Cardiaque, Hospices Civils de Lyon, 69500, Bron, France
| | - Romain Pierrard
- Service de Cardiologie, CHU Nord, 42100, Saint-Étienne, France
| | - Simon Leboube
- Explorations Fonctionnelles Cardiovasculaires, Hospices Civils de Lyon, 69500, Bron, France
- Laboratoire CarMeN - IRIS Team, INSERM, INRA, Université Claude Bernard Lyon-1, Univ-Lyon, 69500, Bron, France
| | - Fadi Farhat
- Chirurgie Cardiaque, Hospices Civils de Lyon, 69500, Bron, France
| | - Marco Vola
- Chirurgie Cardiaque, Hospices Civils de Lyon, 69500, Bron, France
| | | | - Camille Amaz
- Centre d'investigation Clinique, Hospices Civils de Lyon, 69500, Bron, France
| | - Lara Chalabreysse
- Laboratoire d'anatomopathologie, Hospices Civils de Lyon, 69500, Bron, France
| | - Chloe May
- Centre d'investigation Clinique, Hospices Civils de Lyon, 69500, Bron, France
| | - Stephanie Chanon
- Laboratoire CarMeN - IRIS Team, INSERM, INRA, Université Claude Bernard Lyon-1, Univ-Lyon, 69500, Bron, France
| | - Camille Brun
- Laboratoire CarMeN - IRIS Team, INSERM, INRA, Université Claude Bernard Lyon-1, Univ-Lyon, 69500, Bron, France
| | - Lucas Givre
- Laboratoire CarMeN - IRIS Team, INSERM, INRA, Université Claude Bernard Lyon-1, Univ-Lyon, 69500, Bron, France
| | - Gabriel Bidaux
- Laboratoire CarMeN - IRIS Team, INSERM, INRA, Université Claude Bernard Lyon-1, Univ-Lyon, 69500, Bron, France
| | - Nathan Mewton
- Laboratoire CarMeN - IRIS Team, INSERM, INRA, Université Claude Bernard Lyon-1, Univ-Lyon, 69500, Bron, France
- Centre d'investigation Clinique, Hospices Civils de Lyon, 69500, Bron, France
| | - Genevieve Derumeaux
- Explorations Fonctionnelles Cardiovasculaires, Hospices Civils de Lyon, 69500, Bron, France
- INSERM U955, Université Paris-Est Créteil, Créteil, France
- Department of Physiology, AP-HP, Henri Mondor Hospital, FHU SENEC, Créteil, France
| | - Cyrille Bergerot
- Explorations Fonctionnelles Cardiovasculaires, Hospices Civils de Lyon, 69500, Bron, France
- Laboratoire CarMeN - IRIS Team, INSERM, INRA, Université Claude Bernard Lyon-1, Univ-Lyon, 69500, Bron, France
| | - Melanie Paillard
- Laboratoire CarMeN - IRIS Team, INSERM, INRA, Université Claude Bernard Lyon-1, Univ-Lyon, 69500, Bron, France.
| | - Helene Thibault
- Explorations Fonctionnelles Cardiovasculaires, Hospices Civils de Lyon, 69500, Bron, France.
- Laboratoire CarMeN - IRIS Team, INSERM, INRA, Université Claude Bernard Lyon-1, Univ-Lyon, 69500, Bron, France.
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Lee SH, Duron HE, Chaudhuri D. Beyond the TCA cycle: new insights into mitochondrial calcium regulation of oxidative phosphorylation. Biochem Soc Trans 2023; 51:1661-1673. [PMID: 37641565 PMCID: PMC10508640 DOI: 10.1042/bst20230012] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/10/2023] [Accepted: 08/16/2023] [Indexed: 08/31/2023]
Abstract
While mitochondria oxidative phosphorylation is broadly regulated, the impact of mitochondrial Ca2+ on substrate flux under both physiological and pathological conditions is increasingly being recognized. Under physiologic conditions, mitochondrial Ca2+ enters through the mitochondrial Ca2+ uniporter and boosts ATP production. However, maintaining Ca2+ homeostasis is crucial as too little Ca2+ inhibits adaptation to stress and Ca2+ overload can trigger cell death. In this review, we discuss new insights obtained over the past several years expanding the relationship between mitochondrial Ca2+ and oxidative phosphorylation, with most data obtained from heart, liver, or skeletal muscle. Two new themes are emerging. First, beyond boosting ATP synthesis, Ca2+ appears to be a critical determinant of fuel substrate choice between glucose and fatty acids. Second, Ca2+ exerts local effects on the electron transport chain indirectly, not via traditional allosteric mechanisms. These depend critically on the transporters involved, such as the uniporter or the Na+-Ca2+ exchanger. Alteration of these new relationships during disease can be either compensatory or harmful and suggest that targeting mitochondrial Ca2+ may be of therapeutic benefit during diseases featuring impairments in oxidative phosphorylation.
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Affiliation(s)
- Sandra H. Lee
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, USA
| | - Hannah E. Duron
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, USA
| | - Dipayan Chaudhuri
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, USA
- Division of Cardiovascular Medicine, Department of Internal Medicine, Biochemistry, Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
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Gao X, Di X, Li J, Kang Y, Xie W, Sun L, Zhang J. Extracellular Calcium-Induced Calcium Transient Regulating the Proliferation of Osteoblasts through Glycolysis Metabolism Pathways. Int J Mol Sci 2023; 24:4991. [PMID: 36902420 PMCID: PMC10003245 DOI: 10.3390/ijms24054991] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 02/15/2023] [Accepted: 02/22/2023] [Indexed: 03/08/2023] Open
Abstract
During bone remodeling, high extracellular calcium levels accumulated around the resorbing bone tissue as soon as the activation of osteoclasts. However, if and how calcium is involved in the regulation of bone remodeling remains unclear. In this study, the effect of high extracellular calcium concentrations on osteoblast proliferation and differentiation, intracellular calcium ([Ca2+]i) levels, metabolomics, and the expression of proteins related to energy metabolism were investigated. Our results showed that high extracellular calcium levels initiated a [Ca2+]i transient via the calcium-sensing receptor (CaSR) and promoted the proliferation of MC3T3-E1 cells. Metabolomics analysis showed that the proliferation of MC3T3-E1 cells was dependent on aerobic glycolysis, but not the tricarboxylic acid cycle. Moreover, the proliferation and glycolysis of MC3T3-E1 cells were suppressed following the inhibition of AKT. These results indicate that calcium transient triggered by high extracellular calcium levels activated glycolysis via AKT-related signaling pathways and ultimately promoted the proliferation of osteoblasts.
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Affiliation(s)
- Xiaohang Gao
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 711049, China
| | - Xiaohui Di
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 711049, China
| | - Jingjing Li
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 711049, China
| | - Yiting Kang
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 711049, China
| | - Wenjun Xie
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 711049, China
| | - Lijun Sun
- Institute of Sports Biology, Shaanxi Normal University, Xi’an 710119, China
| | - Jianbao Zhang
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 711049, China
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Kim Y, Ajayi PT, Bleck CKE, Glancy B. Three-dimensional remodelling of the cellular energy distribution system during postnatal heart development. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210322. [PMID: 36189814 PMCID: PMC9527916 DOI: 10.1098/rstb.2021.0322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 02/11/2022] [Indexed: 11/12/2022] Open
Abstract
The heart meets the high energy demands of constant muscle contraction and calcium cycling primarily through the conversion of fatty acids into adenosine triphosphate (ATP) by a large volume of mitochondria. As such, the spatial relationships among lipid droplets (LDs), mitochondria, the sarcotubular system and the contractile apparatus are critical to the efficient distribution of energy within the cardiomyocyte. However, the connectivity among components of the cardiac cellular energy distribution system during postnatal development remains unclear. Here, we use volume electron microscopy to demonstrate that the sarcomere branches uniting the myofibrillar network occur more than twice as frequently during early postnatal development as in mature cardiomyocytes. Moreover, we show that the mitochondrial networks arranged in parallel to the contractile apparatus are composed of larger, more compact mitochondria with greater connectivity to adjacent mitochondria in mature as compared with early postnatal cardiomyocytes. Finally, we find that connectivity among mitochondria, LDs and the sarcotubular network is greater in developing than in mature muscles. These data suggest that physical connectivity among cellular structures may facilitate the communication needed to coordinate developmental processes within the cardiac muscle cell. This article is part of the theme issue 'The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease'.
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Affiliation(s)
- Yuho Kim
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
- Department of Physical Therapy and Kinesiology, University of Massachusetts Lowell, Lowell, MA 01854, USA
| | - Peter T. Ajayi
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Christopher K. E. Bleck
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Brian Glancy
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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8
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Parathyroid hormone (PTH) regulation of metabolic homeostasis: An old dog teaches us new tricks. Mol Metab 2022; 60:101480. [PMID: 35338013 PMCID: PMC8980887 DOI: 10.1016/j.molmet.2022.101480] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 02/11/2022] [Accepted: 03/16/2022] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Late in the nineteenth century, it was theorized that a circulating product produced by the parathyroid glands could negatively impact skeletal homeostasis. A century later, intermittent administration of that protein, namely parathyroid hormone (PTH), was approved by the FDA and EMA as the first anabolic agent to treat osteoporosis. Yet, several unanswered but important questions remain about the skeletal actions of PTH. SCOPE OF REVIEW Current research efforts have focused on improving the efficacy of PTH treatment by designing structural analogs and identifying other targets (e.g., the PTH or the calcium sensing receptor). A unique but only recently described aspect of PTH action is its regulation of cellular bioenergetics and metabolism, namely in bone and adipose tissue but also in other tissues. The current review aims to provide a brief background on PTH's previously described actions on bone and highlights how PTH regulates osteoblast bioenergetics, contributing to greater bone formation. It will also shed light on how PTH could alter metabolic homeostasis through its actions in other cells and tissues, thereby impacting the skeleton in a cell non-autonomous manner. MAJOR CONCLUSIONS PTH administration enhances bone formation by targeting the osteoblast through transcriptional changes in several pathways; the most prominent is via adenyl cyclase and PKA. PTH and its related protein, PTHrP, also induce glycolysis and fatty acid oxidation in bone cells and drive lipolysis and thermogenic programming in adipocytes; the latter may indirectly but positively influence skeletal metabolism. While much work remains, alterations in cellular metabolism may also provide a novel mechanism related to PTH's temporal actions. Thus, the bioenergetic impact of PTH can be considered another of the myriad anabolic effects of PTH on the skeleton. Just as importantly from a translational perspective, the non-skeletal metabolic effects may lead to a better understanding of whole-body homeostasis along with new and improved therapies to treat musculoskeletal conditions.
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9
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Pro-inflammatory polarization of macrophages is associated with reduced endoplasmic reticulum-mitochondria interaction. Biochem Biophys Res Commun 2022; 606:61-67. [PMID: 35339753 DOI: 10.1016/j.bbrc.2022.03.086] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 03/16/2022] [Indexed: 11/20/2022]
Abstract
Macrophages play a role in host defense, tissue remodeling and inflammation. Different inflammatory stimuli drive macrophage phenotypes and responses. In this study we investigated the relationship between macrophages immune phenotype and mitochondrial bioenergetics, cell redox state and endoplasmic reticulum (ER)-mitochondria interaction. Bacterial lipopolysaccharide (LPS) and interferon-γ (IFNγ) pro-inflammatory stimuli decreased oxidative metabolism (basal, phosphorylating and maximal conditions) and increased baseline glycolysis (117%) and glycolytic capacity (43%) in THP-1 macrophages. In contrast, interleukin-4 (IL4) and interleukin-13 (IL13) anti-inflammatory stimuli increased the oxygen consumption rates in baseline conditions (21%) and associated with ATP production (19%). LPS + IFNγ stimuli reduced superoxide anion levels by accelerating its conversion into hydrogen peroxide (H2O2) while IL4+IL13 decreased H2O2 release rates. The source of these oxidants was extra-mitochondrial and associated with increased NOX2 and SOD1 gene expression. LPS + IFNγ stimuli decreased ER-mitochondria contact sites as measured by IP3R1-VDAC1 interaction (34%) and markedly upregulated genes involved in mitochondrial fusion (9-10 fold, MFN1 and 2) and fission (∼7 fold, DRP1 and FIS1). Conversely, IL4+IL13 stimuli did not altered ER-mitochondria interactions nor MFN1 and 2 expression. Together, these results unveil ER-mitochondria interaction pattern as a novel feature of macrophage immunological, metabolic and redox profiles.
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10
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Zhao L, Han L, Wei X, Zhou Y, Zhang Y, Si N, Wang H, Yang J, Bian B, Zhao H. Toxicokinetics of Arenobufagin and its Cardiotoxicity Mechanism Exploration Based on Lipidomics and Proteomics Approaches in Rats. Front Pharmacol 2022; 12:780016. [PMID: 35002716 PMCID: PMC8727535 DOI: 10.3389/fphar.2021.780016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/22/2021] [Indexed: 12/17/2022] Open
Abstract
Arenobufagin (ArBu), one of the main active bufadienolides of toad venom with cardiotonic effect, analgesic effect, and outstanding anti-tumor potentiality, is also a potential cardiotoxic component. In the present study, the cardiac effect of ArBu and its underlying mechanism were explored by integrating data such as heart rates, toxicokinetics, myocardial enzyme and brain natriuretic peptide (BNP) activity, pathological sections, lipidomics and proteomics. Under different doses, the cardiac effects turned out to be different. The oral dose of 60 mg/kg of ArBu sped up the heart rate. However, 120 mg/kg ArBu mainly reduced the heart rate. Over time, they all returned to normal, consisting of the trend of ArBu concentration-time curve. High concentrations of myocardial enzymes and BNP indicated that ArBu inhibited or impaired the cardiac function of rats. Pathological sections of hearts also showed that ArBu caused myocardial fiber disorder and rupture, in which the high-dose group was more serious. At the same time, serum and heart tissue lipidomics were used to explore the changes in body lipid metabolism under different doses. The data indicated a larger difference in the high-dose ArBu group. There were likewise many significant differences in the proteomics of the heart. Furthermore, a multi-layered network was used to integrate the above information to explore the potential mechanism. Finally, 4 proteins that were shown to be significantly and differentially expressed were validated by targeted proteomics using parallel reaction monitoring (PRM) analysis. Our findings indicated that ArBu behaved as a bidirectional regulation of the heart. The potential mechanism of cardiac action was revealed with the increased dose, which provided a useful reference for the safety of clinical application of ArBu.
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Affiliation(s)
- Lijuan Zhao
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China.,Shaanxi Chinese Medicine Institute (Shaanxi Pharmaceutical Information Center), Xianyang, China
| | - Lingyu Han
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China.,School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Xiaolu Wei
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yanyan Zhou
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yanqiong Zhang
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Nan Si
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Hongjie Wang
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jian Yang
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Baolin Bian
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Haiyu Zhao
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
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11
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Bassoy EY, Walch M, Martinvalet D. Reactive Oxygen Species: Do They Play a Role in Adaptive Immunity? Front Immunol 2021; 12:755856. [PMID: 34899706 PMCID: PMC8653250 DOI: 10.3389/fimmu.2021.755856] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/29/2021] [Indexed: 12/12/2022] Open
Abstract
The immune system protects the host from a plethora of microorganisms and toxins through its unique ability to distinguish self from non-self. To perform this delicate but essential task, the immune system relies on two lines of defense. The innate immune system, which is by nature fast acting, represents the first line of defense. It involves anatomical barriers, physiological factors as well as a subset of haematopoietically-derived cells generically call leukocytes. Activation of the innate immune response leads to a state of inflammation that serves to both warn about and combat the ongoing infection and delivers the antigenic information of the invading pathogens to initiate the slower but highly potent and specific second line of defense, the adaptive immune system. The adaptive immune response calls on T lymphocytes as well as the B lymphocytes essential for the elimination of pathogens and the establishment of the immunological memory. Reactive oxygen species (ROS) have been implicated in many aspects of the immune responses to pathogens, mostly in innate immune functions, such as the respiratory burst and inflammasome activation. Here in this mini review, we focus on the role of ROS in adaptive immunity. We examine how ROS contribute to T-cell biology and discuss whether this activity can be extrapolated to B cells.
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Affiliation(s)
- Esen Yonca Bassoy
- International Society of Liver Surgeons (ISLS), Cankaya Ankara, Turkey.,Departments of Immunology and Cancer Biology, College of Medicine and Science, Mayo Clinic, Scottsdale, AZ, United States
| | - Michael Walch
- Faculty of Science and Medicine, Department of Oncology, Microbiology and Immunology, Anatomy Unit, University of Fribourg, Fribourg, Switzerland
| | - Denis Martinvalet
- Department of Biomedical Sciences, University of Padua, Padova, Italy.,Veneto Institute of Molecular Medicine, Padova, Italy
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12
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Mitochondrial calcium uniporter affects neutrophil bactericidal activity during Staphylococcus aureus infection. Infect Immun 2021; 90:e0055121. [PMID: 34871043 DOI: 10.1128/iai.00551-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neutrophils simultaneously restrict Staphylococcus aureus dissemination and facilitate bactericidal activity during infection through the formation of neutrophil extracellular traps (NETs). Neutrophils that produce higher levels of mitochondrial superoxide undergo enhanced terminal NET formation (suicidal NETosis) in response to S. aureus; however, mechanisms regulating mitochondrial homeostasis upstream of neutrophil antibacterial processes are not fully resolved. Here, we demonstrate that mitochondrial calcium uptake 1 (MICU1)-deficient (MICU1-/-) neutrophils accumulate higher levels of calcium and iron within the mitochondria in a mitochondrial calcium uniporter (MCU)-dependent manner. Corresponding with increased ion flux through the MCU, mitochondrial superoxide production is elevated, thereby increasing the propensity for MICU1-/- neutrophils to undergo suicidal NETosis rather than primary degranulation in response to S. aureus. Increased NET formation augments macrophage killing of bacterial pathogens. Similarly, MICU1-/- neutrophils alone are not more antibacterial towards S. aureus, but rather enhanced suicidal NETosis by MICU1-/- neutrophils facilitates increased bactericidal activity in the presence of macrophages. Similarly, mice with a deficiency in MICU1 restricted to cells expressing LysM exhibit lower bacterial burdens in the heart with increased survival during systemic S. aureus infection. Coinciding with the decrease in S. aureus burdens, MICU1-/- neutrophils in the heart produced higher levels of mitochondrial superoxide and undergo enhanced suicidal NETosis. These results demonstrate that ion flux by the MCU affects the antibacterial function of neutrophils during S. aureus infection.
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13
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Abstract
The design of the energy metabolism system in striated muscle remains a major area of investigation. Here, we review our current understanding and emerging hypotheses regarding the metabolic support of muscle contraction. Maintenance of ATP free energy, so called energy homeostasis, via mitochondrial oxidative phosphorylation is critical to sustained contractile activity, and this major design criterion is the focus of this review. Cell volume invested in mitochondria reduces the space available for generating contractile force, and this spatial balance between mitochondria acontractile elements to meet the varying sustained power demands across muscle types is another important design criterion. This is accomplished with remarkably similar mass-specific mitochondrial protein composition across muscle types, implying that it is the organization of mitochondria within the muscle cell that is critical to supporting sustained muscle function. Beyond the production of ATP, ubiquitous distribution of ATPases throughout the muscle requires rapid distribution of potential energy across these large cells. Distribution of potential energy has long been thought to occur primarily through facilitated metabolite diffusion, but recent analysis has questioned the importance of this process under normal physiological conditions. Recent structural and functional studies have supported the hypothesis that the mitochondrial reticulum provides a rapid energy distribution system via the conduction of the mitochondrial membrane potential to maintain metabolic homeostasis during contractile activity. We extensively review this aspect of the energy metabolism design contrasting it with metabolite diffusion models and how mitochondrial structure can play a role in the delivery of energy in the striated muscle.
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Affiliation(s)
- Brian Glancy
- Muscle Energetics Laboratory, National Heart, Lung, and Blood Insititute and National Institute of Arthritis and Musculoskeletal and Skin Disease, Bethesda, Maryland
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Insititute, Bethesda, Maryland
| | - Robert S Balaban
- Muscle Energetics Laboratory, National Heart, Lung, and Blood Insititute and National Institute of Arthritis and Musculoskeletal and Skin Disease, Bethesda, Maryland
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Insititute, Bethesda, Maryland
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14
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Memme JM, Slavin M, Moradi N, Hood DA. Mitochondrial Bioenergetics and Turnover during Chronic Muscle Disuse. Int J Mol Sci 2021; 22:ijms22105179. [PMID: 34068411 PMCID: PMC8153634 DOI: 10.3390/ijms22105179] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/07/2021] [Accepted: 05/11/2021] [Indexed: 12/15/2022] Open
Abstract
Periods of muscle disuse promote marked mitochondrial alterations that contribute to the impaired metabolic health and degree of atrophy in the muscle. Thus, understanding the molecular underpinnings of muscle mitochondrial decline with prolonged inactivity is of considerable interest. There are translational applications to patients subjected to limb immobilization following injury, illness-induced bed rest, neuropathies, and even microgravity. Studies in these patients, as well as on various pre-clinical rodent models have elucidated the pathways involved in mitochondrial quality control, such as mitochondrial biogenesis, mitophagy, fission and fusion, and the corresponding mitochondrial derangements that underlie the muscle atrophy that ensues from inactivity. Defective organelles display altered respiratory function concurrent with increased accumulation of reactive oxygen species, which exacerbate myofiber atrophy via degradative pathways. The preservation of muscle quality and function is critical for maintaining mobility throughout the lifespan, and for the prevention of inactivity-related diseases. Exercise training is effective in preserving muscle mass by promoting favourable mitochondrial adaptations that offset the mitochondrial dysfunction, which contributes to the declines in muscle and whole-body metabolic health. This highlights the need for further investigation of the mechanisms in which mitochondria contribute to disuse-induced atrophy, as well as the specific molecular targets that can be exploited therapeutically.
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Affiliation(s)
| | | | | | - David A. Hood
- Correspondence: ; Tel.: +1-(416)-736-2100 (ext. 66640)
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15
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Hyatt HW, Powers SK. Disturbances in Calcium Homeostasis Promotes Skeletal Muscle Atrophy: Lessons From Ventilator-Induced Diaphragm Wasting. Front Physiol 2020; 11:615351. [PMID: 33391032 PMCID: PMC7773636 DOI: 10.3389/fphys.2020.615351] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 11/19/2020] [Indexed: 12/23/2022] Open
Abstract
Mechanical ventilation (MV) is often a life-saving intervention for patients in respiratory failure. Unfortunately, a common and undesired consequence of prolonged MV is the development of diaphragmatic atrophy and contractile dysfunction. This MV-induced diaphragmatic weakness is commonly labeled “ventilator-induced diaphragm dysfunction” (VIDD). VIDD is an important clinical problem because diaphragmatic weakness is a major risk factor for the failure to wean patients from MV; this inability to remove patients from ventilator support results in prolonged hospitalization and increased morbidity and mortality. Although several processes contribute to the development of VIDD, it is clear that oxidative stress leading to the rapid activation of proteases is a primary contributor. While all major proteolytic systems likely contribute to VIDD, emerging evidence reveals that activation of the calcium-activated protease calpain plays a required role. This review highlights the signaling pathways leading to VIDD with a focus on the cellular events that promote increased cytosolic calcium levels and the subsequent activation of calpain within diaphragm muscle fibers. In particular, we discuss the emerging evidence that increased mitochondrial production of reactive oxygen species promotes oxidation of the ryanodine receptor/calcium release channel, resulting in calcium release from the sarcoplasmic reticulum, accelerated proteolysis, and VIDD. We conclude with a discussion of important and unanswered questions associated with disturbances in calcium homeostasis in diaphragm muscle fibers during prolonged MV.
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Affiliation(s)
- Hayden W Hyatt
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Scott K Powers
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
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16
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English J, Son JM, Cardamone MD, Lee C, Perissi V. Decoding the rosetta stone of mitonuclear communication. Pharmacol Res 2020; 161:105161. [PMID: 32846213 PMCID: PMC7755734 DOI: 10.1016/j.phrs.2020.105161] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/04/2020] [Accepted: 08/14/2020] [Indexed: 12/12/2022]
Abstract
Cellular homeostasis in eukaryotic cells requires synchronized coordination of multiple organelles. A key role in this stage is played by mitochondria, which have recently emerged as highly interconnected and multifunctional hubs that process and coordinate diverse cellular functions. Beyond producing ATP, mitochondria generate key metabolites and are central to apoptotic and metabolic signaling pathways. Because most mitochondrial proteins are encoded in the nuclear genome, the biogenesis of new mitochondria and the maintenance of mitochondrial functions and flexibility critically depend upon effective mitonuclear communication. This review addresses the complex network of signaling molecules and pathways allowing mitochondria-nuclear communication and coordinated regulation of their independent but interconnected genomes, and discusses the extent to which dynamic communication between the two organelles has evolved for mutual benefit and for the overall maintenance of cellular and organismal fitness.
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Affiliation(s)
- Justin English
- Department of Biochemistry, Boston University, Boston, MA, 02115, USA; Graduate Program in Biomolecular Pharmacology, Department of Pharmacology and Experimental Therapeutics, Boston University, Boston, MA, 02115, USA
| | - Jyung Mean Son
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | | | - Changhan Lee
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA; USC Norris Comprehensive Cancer Center, Los Angeles, CA, 90089, USA; Biomedical Sciences, Graduate School, Ajou University, Suwon, 16499, South Korea
| | - Valentina Perissi
- Department of Biochemistry, Boston University, Boston, MA, 02115, USA.
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17
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Fisher-Wellman KH, Davidson MT, Narowski TM, Lin CT, Koves TR, Muoio DM. Mitochondrial Diagnostics: A Multiplexed Assay Platform for Comprehensive Assessment of Mitochondrial Energy Fluxes. Cell Rep 2019; 24:3593-3606.e10. [PMID: 30257218 DOI: 10.1016/j.celrep.2018.08.091] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 06/23/2018] [Accepted: 08/29/2018] [Indexed: 12/17/2022] Open
Abstract
Chronic metabolic diseases have been linked to molecular signatures of mitochondrial dysfunction. Nonetheless, molecular remodeling of the transcriptome, proteome, and/or metabolome does not necessarily translate to functional consequences that confer physiologic phenotypes. The work here aims to bridge the gap between molecular and functional phenomics by developing and validating a multiplexed assay platform for comprehensive assessment of mitochondrial energy transduction. The diagnostic power of the platform stems from a modified version of the creatine kinase energetic clamp technique, performed in parallel with multiplexed analyses of dehydrogenase activities and ATP synthesis rates. Together, these assays provide diagnostic coverage of the mitochondrial network at a level approaching that gained by molecular "-omics" technologies. Application of the platform to a comparison of skeletal muscle versus heart mitochondria reveals mechanistic insights into tissue-specific distinctions in energy transfer efficiency. This platform opens exciting opportunities to unravel the connection between mitochondrial bioenergetics and human disease.
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Affiliation(s)
- Kelsey H Fisher-Wellman
- Departments of Medicine and Pharmacology and Cancer Biology, Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University, Durham, NC 27701, USA; East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA.
| | - Michael T Davidson
- Departments of Medicine and Pharmacology and Cancer Biology, Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University, Durham, NC 27701, USA
| | - Tara M Narowski
- Departments of Medicine and Pharmacology and Cancer Biology, Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University, Durham, NC 27701, USA
| | - Chien-Te Lin
- East Carolina Diabetes and Obesity Institute, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Timothy R Koves
- Departments of Medicine and Pharmacology and Cancer Biology, Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University, Durham, NC 27701, USA
| | - Deborah M Muoio
- Departments of Medicine and Pharmacology and Cancer Biology, Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University, Durham, NC 27701, USA.
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18
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Miller BA, Wang J, Song J, Zhang XQ, Hirschler-Laszkiewicz I, Shanmughapriya S, Tomar D, Rajan S, Feldman AM, Madesh M, Sheu SS, Cheung JY. Trpm2 enhances physiological bioenergetics and protects against pathological oxidative cardiac injury: Role of Pyk2 phosphorylation. J Cell Physiol 2019; 234:15048-15060. [PMID: 30637731 PMCID: PMC6626587 DOI: 10.1002/jcp.28146] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 01/03/2019] [Indexed: 01/25/2023]
Abstract
The mechanisms by which Trpm2 channels enhance mitochondrial bioenergetics and protect against oxidative stress-induced cardiac injury remain unclear. Here, the role of proline-rich tyrosine kinase 2 (Pyk2) in Trpm2 signaling is explored. Activation of Trpm2 in adult myocytes with H2 O2 resulted in 10- to 21-fold increases in Pyk2 phosphorylation in wild-type (WT) myocytes which was significantly lower (~40%) in Trpm2 knockout (KO) myocytes. Pyk2 phosphorylation was inhibited (~54%) by the Trpm2 blocker clotrimazole. Buffering Trpm2-mediated Ca2+ increase with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) resulted in significantly reduced pPyk2 in WT but not in KO myocytes, indicating Ca2+ influx through activated Trpm2 channels phosphorylated Pyk2. Part of phosphorylated Pyk2 translocated from cytosol to mitochondria which has been previously shown to augment mitochondrial Ca2+ uptake and enhance adenosine triphosphate generation. Although Trpm2-mediated Ca2+ influx phosphorylated Ca2+ -calmodulin kinase II (CaMKII), the CaMKII inhibitor KN93 did not significantly affect Pyk2 phosphorylation in H2 O2 -treated WT myocytes. After ischemia/reperfusion (I/R), Pyk2 phosphorylation and its downstream prosurvival signaling molecules (pERK1/2 and pAkt) were significantly lower in KO-I/R when compared with WT-I/R hearts. After hypoxia/reoxygenation, mitochondrial membrane potential was lower and superoxide level was higher in KO myocytes, and were restored to WT values by the mitochondria-targeted superoxide scavenger MitoTempo. Our results suggested that Ca2+ influx via tonically activated Trpm2 phosphorylated Pyk2, part of which translocated to mitochondria, resulting in better mitochondrial bioenergetics to maintain cardiac health. After I/R, Pyk2 activated prosurvival signaling molecules and prevented excessive increases in reactive oxygen species, thereby affording protection from I/R injury.
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Affiliation(s)
- Barbara A. Miller
- Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - JuFang Wang
- Center of Translational Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, PA 19140
| | - Jianliang Song
- Center of Translational Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, PA 19140
| | - Xue-Qian Zhang
- Center of Translational Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, PA 19140
| | - Iwona Hirschler-Laszkiewicz
- Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Santhanam Shanmughapriya
- Center of Translational Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, PA 19140,Department of Biochemistry, Lewis Katz School of Medicine of Temple University, Philadelphia, PA 19140
| | - Dhanendra Tomar
- Center of Translational Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, PA 19140,Department of Biochemistry, Lewis Katz School of Medicine of Temple University, Philadelphia, PA 19140
| | - Sudasan Rajan
- Center of Translational Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, PA 19140,Department of Biochemistry, Lewis Katz School of Medicine of Temple University, Philadelphia, PA 19140
| | - Arthur M. Feldman
- Department of Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, PA 19140
| | - Muniswamy Madesh
- Center of Translational Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, PA 19140,Department of Biochemistry, Lewis Katz School of Medicine of Temple University, Philadelphia, PA 19140
| | - Shey-Shing Sheu
- Center for Translational Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Joseph Y. Cheung
- Center of Translational Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, PA 19140,Department of Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, PA 19140
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19
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Haumann J, Camara AKS, Gadicherla AK, Navarro CD, Boelens AD, Blomeyer CA, Dash RK, Boswell MR, Kwok WM, Stowe DF. Slow Ca 2+ Efflux by Ca 2+/H + Exchange in Cardiac Mitochondria Is Modulated by Ca 2+ Re-uptake via MCU, Extra-Mitochondrial pH, and H + Pumping by F OF 1-ATPase. Front Physiol 2019; 9:1914. [PMID: 30804812 PMCID: PMC6378946 DOI: 10.3389/fphys.2018.01914] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 12/18/2018] [Indexed: 02/04/2023] Open
Abstract
Mitochondrial (m) Ca2+ influx is largely dependent on membrane potential (ΔΨm), whereas mCa2+ efflux occurs primarily via Ca2+ ion exchangers. We probed the kinetics of Ca2+/H+ exchange (CHEm) in guinea pig cardiac muscle mitochondria. We tested if net mCa2+ flux is altered during a matrix inward H+ leak that is dependent on matrix H+ pumping by ATPm hydrolysis at complex V (FOF1-ATPase). We measured [Ca2+]m, extra-mitochondrial (e) [Ca2+]e, ΔΨm, pHm, pHe, NADH, respiration, ADP/ATP ratios, and total [ATP]m in the presence or absence of protonophore dinitrophenol (DNP), mitochondrial uniporter (MCU) blocker Ru360, and complex V blocker oligomycin (OMN). We proposed that net slow influx/efflux of Ca2+ after adding DNP and CaCl2 is dependent on whether the ΔpHm gradient is/is not maintained by reciprocal outward H+ pumping by complex V. We found that adding CaCl2 enhanced DNP-induced increases in respiration and decreases in ΔΨm while [ATP]m decreased, ΔpHm gradient was maintained, and [Ca2+]m continued to increase slowly, indicating net mCa2+ influx via MCU. In contrast, with complex V blocked by OMN, adding DNP and CaCl2 caused larger declines in ΔΨm as well as a slow fall in pHm to near pHe while [Ca2+]m continued to decrease slowly, indicating net mCa2+ efflux in exchange for H+ influx (CHEm) until the ΔpHm gradient was abolished. The kinetics of slow mCa2+ efflux with slow H+ influx via CHEm was also observed at pHe 6.9 vs. 7.6 by the slow fall in pHm until ΔpHm was abolished; if Ca2+ reuptake via the MCU was also blocked, mCa2+ efflux via CHEm became more evident. Of the two components of the proton electrochemical gradient, our results indicate that CHEm activity is driven largely by the ΔpHm chemical gradient with H+ leak, while mCa2+ entry via MCU depends largely on the charge gradient ΔΨm. A fall in ΔΨm with excess mCa2+ loading can occur during cardiac cell stress. Cardiac cell injury due to mCa2+ overload may be reduced by temporarily inhibiting FOF1-ATPase from pumping H+ due to ΔΨm depolarization. This action would prevent additional slow mCa2+ loading via MCU and permit activation of CHEm to mediate efflux of mCa2+. HIGHLIGHTSWe examined how slow mitochondrial (m) Ca2+ efflux via Ca2+/H+ exchange (CHEm) is triggered by matrix acidity after a rapid increase in [Ca2+]m by adding CaCl2 in the presence of dinitrophenol (DNP) to permit H+ influx, and oligomycin (OMN) to block H+ pumping via FOF1-ATP synthase/ase (complex V). Declines in ΔΨm and pHm after DNP and added CaCl2 were larger when complex V was blocked. [Ca2+]m slowly increased despite a fall in ΔΨm but maintained pHm when H+ pumping by complex V was permitted. [Ca2+]m slowly decreased and external [Ca2+]e increased with declines in both ΔΨm and pHm when complex V was blocked. ATPm hydrolysis supports a falling pHm and redox state and promotes a slow increase in [Ca2+]m. After rapid Ca2+ influx due to a bolus of CaCl2, slow mCa2+ efflux by CHEm occurs directly if pHe is low.
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Affiliation(s)
- Johan Haumann
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Amadou K S Camara
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Cancer Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Ashish K Gadicherla
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Christopher D Navarro
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Age D Boelens
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Christoph A Blomeyer
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Ranjan K Dash
- Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, Milwaukee, WI, United States
| | - Michael R Boswell
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Wai-Meng Kwok
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Cancer Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - David F Stowe
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, Milwaukee, WI, United States.,Research Service, Veterans Affairs Medical Center, Milwaukee, WI, United States
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20
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Kasper JD, Meyer RA, Beard DA, Wiseman RW. Effects of altered pyruvate dehydrogenase activity on contracting skeletal muscle bioenergetics. Am J Physiol Regul Integr Comp Physiol 2018; 316:R76-R86. [PMID: 30462525 DOI: 10.1152/ajpregu.00321.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
During aerobic exercise (>65% of maximum oxygen consumption), the primary source of acetyl-CoA to fuel oxidative ATP synthesis in muscle is the pyruvate dehydrogenase (PDH) reaction. This study investigated how regulation of PDH activity affects muscle energetics by determining whether activation of PDH with dichloroacetate (DCA) alters the dynamics of the phosphate potential of rat gastrocnemius muscle during contraction. Twitch contractions were induced in vivo over a broad range of intensities to sample submaximal and maximal aerobic workloads. Muscle phosphorus metabolites were measured in vivo before and after DCA treatment by phosphorus nuclear magnetic resonance spectroscopy. At rest, DCA increased PDH activation compared with control (90 ± 12% vs. 23 ± 3%, P < 0.05), with parallel decreases in inorganic phosphate (Pi) of 17% (1.4 ± 0.2 vs. 1.7 ± 0.1 mM, P < 0.05) and an increase in the free energy of ATP hydrolysis (ΔGATP) (-66.2 ± 0.3 vs. -65.6 ± 0.2 kJ/mol, P < 0.05). During stimulation DCA increased steady-state phosphocreatine (PCr) and the magnitude of ΔGATP, with concomitant reduction in Pi and ADP concentrations. These effects were not due to kinetic alterations in PCr hydrolysis, resynthesis, or glycolytic ATP production and altered the flow-force relationship between mitochondrial ATP synthesis rate and ΔGATP. DCA had no significant effect at 1.0- to 2.0-Hz stimulation because physiological mechanisms at these high stimulation levels cause maximal activation of PDH. These data support a role of PDH activation in the regulation of the energetic steady state by altering the phosphate potential (ΔGATP) at rest and during contraction.
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Affiliation(s)
- Jonathan D Kasper
- Department of Physiology, Michigan State University , East Lansing, Michigan
| | - Ronald A Meyer
- Department of Physiology, Michigan State University , East Lansing, Michigan.,Department of Radiology, Michigan State University , East Lansing, Michigan
| | - Daniel A Beard
- Department of Molecular and Integrative Physiology, University of Michigan , Ann Arbor, Michigan
| | - Robert W Wiseman
- Department of Physiology, Michigan State University , East Lansing, Michigan.,Department of Radiology, Michigan State University , East Lansing, Michigan
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21
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Martinvalet D. The role of the mitochondria and the endoplasmic reticulum contact sites in the development of the immune responses. Cell Death Dis 2018; 9:336. [PMID: 29491398 PMCID: PMC5832423 DOI: 10.1038/s41419-017-0237-7] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 11/25/2017] [Accepted: 11/28/2017] [Indexed: 12/12/2022]
Abstract
Mitochondria and endoplasmic reticulum (ER) contact sites (MERCs) are dynamic modules enriched in subset of lipids and specialized proteins that determine their structure and functions. The MERCs regulate lipid transfer, autophagosome formation, mitochondrial fission, Ca2+ homeostasis and apoptosis. Since these functions are essential for cell biology, it is therefore not surprising that MERCs also play a critical role in organ physiology among which the immune system stands by its critical host defense function. This defense system must discriminate and tolerate host cells and beneficial commensal microorganisms while eliminating pathogenic ones in order to preserve normal homeostasis. To meet this goal, the immune system has two lines of defense. First, the fast acting but unspecific innate immune system relies on anatomical physical barriers and subsets of hematopoietically derived cells expressing germline-encoded receptors called pattern recognition receptors (PRR) recognizing conserved motifs on the pathogens. Second, the slower but very specific adaptive immune response is added to complement innate immunity. Adaptive immunity relies on another set of specialized cells, the lymphocytes, harboring receptors requiring somatic recombination to be expressed. Both innate and adaptive immune cells must be activated to phagocytose and process pathogens, migrate, proliferate, release soluble factors and destroy infected cells. Some of these functions are strongly dependent on lipid transfer, autophagosome formation, mitochondrial fission, and Ca2+ flux; this indicates that MERCs could regulate immunity.
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Affiliation(s)
- Denis Martinvalet
- Department of Cell Physiology and Metabolism, Geneva Medical School, 1211, Geneva, Switzerland.
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22
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Parks RJ, Murphy E, Liu JC. Mitochondrial Permeability Transition Pore and Calcium Handling. Methods Mol Biol 2018; 1782:187-196. [PMID: 29851001 DOI: 10.1007/978-1-4939-7831-1_11] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The opening of a large conductance channel in the inner mitochondrial membrane, known as the mitochondrial permeability transition pore (PTP), has been shown to be a primary mediator of cell death in the heart subjected to ischemia-reperfusion injury. Inhibitors of the PTP have been shown to reduce cardiac ischemia-reperfusion injury in many animal models. Furthermore, most cardioprotective strategies appear to reduce ischemic cell death either by reducing the triggers for the opening of the PTP, such as reducing calcium overload or reactive oxygen species, or by inhibiting PTP modulators. This chapter will focus on key issues in the study of the PTP and provide some methods for measuring PTP opening in isolated mitochondria.
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Affiliation(s)
- Randi J Parks
- Systems Biology Center, NHLBI, NIH, Bethesda, MD, 20892, USA
| | | | - Julia C Liu
- Systems Biology Center, NHLBI, NIH, Bethesda, MD, 20892, USA.
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Chen Z, Jin Z, Xia Y, Zhao S, Xu X, Papadimos TJ, Wang Q. The protective effect of lipid emulsion in preventing bupivacaine-induced mitochondrial injury and apoptosis of H9C2 cardiomyocytes. Drug Deliv 2017; 24:430-436. [PMID: 28165812 PMCID: PMC8241039 DOI: 10.1080/10717544.2016.1261379] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Lipid emulsion (LE) has been shown to be effective in the resuscitation of bupivacaine-induced cardiac arrest, but the precise mechanism of this action has not been fully elucidated. Pursuant to this lack of information on the mechanism in which LE protects the myocardium during bupivacaine-induced toxicity, we explored mitochondrial function and cell apoptosis. H9C2 cardiomyocytes were used in study. Cells were randomly divided in different groups and were cultivated 6 h, 12 h, and 24 h. The mitochondria were extracted and mitochondrial ATP content was measured, as was mitochondrial membrane potential, the concentration of calcium ion (Ca2+), and the activity of Ca2+-ATP enzyme (Ca2+-ATPase). Cells from groups Bup1000, LE group, and Bup1000LE were collected to determine cell viability, cell apoptosis, and electron microscopy scanning of mitochondrial ultrastructure (after 24 h). We found that LE can reverse the inhibition of the mitochondrial function induced by bupivacaine, regulate the concentration of calcium ion in mitochondria, resulting in the protection of myocardial cells from toxicity induced by bupivacaine.
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Affiliation(s)
- Zhe Chen
- a Department of Anesthesiology, The First Affiliated Hospital, Wenzhou Medical University , Wenzhou , China
| | - Zhousheng Jin
- a Department of Anesthesiology, The First Affiliated Hospital, Wenzhou Medical University , Wenzhou , China
| | - Yun Xia
- b Department of Anesthesiology, The Ohio State University Medical Center , Columbus , OH , USA , and
| | - Shishi Zhao
- a Department of Anesthesiology, The First Affiliated Hospital, Wenzhou Medical University , Wenzhou , China
| | - Xuzhong Xu
- a Department of Anesthesiology, The First Affiliated Hospital, Wenzhou Medical University , Wenzhou , China
| | - Thomas J Papadimos
- c Department of Anesthesiology, University of Toledo College of Medicine and Life Sciences , Toledo , OH , USA
| | - Quanguang Wang
- a Department of Anesthesiology, The First Affiliated Hospital, Wenzhou Medical University , Wenzhou , China
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Zhang Y, Avalos JL. Traditional and novel tools to probe the mitochondrial metabolism in health and disease. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2017; 9. [PMID: 28067471 DOI: 10.1002/wsbm.1373] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/07/2016] [Accepted: 11/09/2016] [Indexed: 02/06/2023]
Abstract
Mitochondrial metabolism links energy production to other essential cellular processes such as signaling, cellular differentiation, and apoptosis. In addition to producing adenosine triphosphate (ATP) as an energy source, mitochondria are responsible for the synthesis of a myriad of important metabolites and cofactors such as tetrahydrofolate, α-ketoacids, steroids, aminolevulinic acid, biotin, lipoic acid, acetyl-CoA, iron-sulfur clusters, heme, and ubiquinone. Furthermore, mitochondria and their metabolism have been implicated in aging and several human diseases, including inherited mitochondrial disorders, cardiac dysfunction, heart failure, neurodegenerative diseases, diabetes, and cancer. Therefore, there is great interest in understanding mitochondrial metabolism and the complex relationship it has with other cellular processes. A large number of studies on mitochondrial metabolism have been conducted in the last 50 years, taking a broad range of approaches. In this review, we summarize and discuss the most commonly used tools that have been used to study different aspects of the metabolism of mitochondria: ranging from dyes that monitor changes in the mitochondrial membrane potential and pharmacological tools to study respiration or ATP synthesis, to more modern tools such as genetically encoded biosensors and trans-omic approaches enabled by recent advances in mass spectrometry, computation, and other technologies. These tools have allowed the large number of studies that have shaped our current understanding of mitochondrial metabolism. WIREs Syst Biol Med 2017, 9:e1373. doi: 10.1002/wsbm.1373 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Yanfei Zhang
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - José L Avalos
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.,Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, USA.,Department of Molecular Biology, Princeton University, Princeton, NJ, USA
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Abstract
The endoplasmic reticulum (ER) is a crucial organelle for coordinating cellular Ca2+ signaling and protein synthesis and folding. Moreover, the dynamic and complex membranous structures constituting the ER allow the formation of contact sites with other organelles and structures, including among others the mitochondria and the plasma membrane (PM). The contact sites that the ER form with mitochondria is a hot topic in research, and the nature of the so-called mitochondria-associated membranes (MAMs) is continuously evolving. The MAMs consist of a proteinaceous tether that physically connects the ER with mitochondria. The MAMs harness the main functions of both organelles to form a specialized subcompartment at the interface of the ER and mitochondria. Under homeostatic conditions, MAMs are crucial for the efficient transfer of Ca2+ from the ER to mitochondria, and for proper mitochondria bioenergetics and lipid synthesis. MAMs are also believed to be the master regulators of mitochondrial shape and motility, and to form a crucial site for autophagosome assembly. Not surprisingly, MAMs have been shown to be a hot spot for the transfer of stress signals from the ER to mitochondria, most notably under the conditions of loss of ER proteostasis, by engaging the unfolded protein response (UPR). In this chapter after an introduction on ER biology and ER stress, we will review the emerging and key signaling roles of the MAMs, which have a root in cellular processes and signaling cascades coordinated by the ER.
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Manfredi G, Kawamata H. Mitochondria and endoplasmic reticulum crosstalk in amyotrophic lateral sclerosis. Neurobiol Dis 2015; 90:35-42. [PMID: 26282323 DOI: 10.1016/j.nbd.2015.08.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 07/31/2015] [Accepted: 08/12/2015] [Indexed: 12/13/2022] Open
Abstract
Physical and functional interactions between mitochondria and the endoplasmic reticulum (ER) are crucial for cell life. These two organelles are intimately connected and collaborate to essential processes, such as calcium homeostasis and phospholipid biosynthesis. The connections between mitochondria and endoplasmic reticulum occur through structures named mitochondria associated membranes (MAMs), which contain lipid rafts and a large number of proteins, many of which serve multiple functions at different cellular sites. Growing evidence strongly suggests that alterations of ER-mitochondria interactions are involved in neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), a devastating and rapidly fatal motor neuron disease. Mutations in proteins that participate in ER-mitochondria interactions and MAM functions are increasingly being associated with genetic forms of ALS and other neurodegenerative diseases. This evidence strongly suggests that, rather than considering the two organelles separately, a better understanding of the disease process can derive from studying the alterations in their crosstalk. In this review we discuss normal and pathological ER-mitochondria interactions and the evidence that link them to ALS.
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Affiliation(s)
- Giovanni Manfredi
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, 401 East 61st Street, New York, NY 10065, United States.
| | - Hibiki Kawamata
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, 401 East 61st Street, New York, NY 10065, United States.
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Epidermal TRPM8 channel isoform controls the balance between keratinocyte proliferation and differentiation in a cold-dependent manner. Proc Natl Acad Sci U S A 2015; 112:E3345-54. [PMID: 26080404 DOI: 10.1073/pnas.1423357112] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Deviation of the ambient temperature is one of the most ubiquitous stimuli that continuously affect mammals' skin. Although the role of the warmth receptors in epidermal homeostasis (EH) was elucidated in recent years, the mystery of the keratinocyte mild-cold sensor remains unsolved. Here we report the cloning and characterization of a new functional epidermal isoform of the transient receptor potential M8 (TRPM8) mild-cold receptor, dubbed epidermal TRPM8 (eTRPM8), which is localized in the keratinocyte endoplasmic reticulum membrane and controls mitochondrial Ca(2+) concentration ([Ca(2+)]m). In turn, [Ca(2+)]m modulates ATP and superoxide (O2(·-)) synthesis in a cold-dependent manner. We report that this fine tuning of ATP and O2(·-) levels by cooling controls the balance between keratinocyte proliferation and differentiation. Finally, to ascertain eTRPM8's role in EH in vivo we developed a new functional knockout mouse strain by deleting the pore domain of TRPM8 and demonstrated that eTRPM8 knockout impairs adaptation of the epidermis to low temperatures.
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Manko BO, Manko VV. Influence of Са(2+) on kinetic parameters of pancreatic acinar mitochondria in situ respiration. UKRAINIAN BIOCHEMICAL JOURNAL 2013. [DOI: 10.15407/ubj85.04.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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29
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Glancy B, Willis WT, Chess DJ, Balaban RS. Effect of calcium on the oxidative phosphorylation cascade in skeletal muscle mitochondria. Biochemistry 2013; 52:2793-809. [PMID: 23547908 DOI: 10.1021/bi3015983] [Citation(s) in RCA: 228] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Calcium is believed to regulate mitochondrial oxidative phosphorylation, thereby contributing to the maintenance of cellular energy homeostasis. Skeletal muscle, with an energy conversion dynamic range of up to 100-fold, is an extreme case for evaluating the cellular balance of ATP production and consumption. This study examined the role of Ca(2+) in the entire oxidative phosphorylation reaction network in isolated skeletal muscle mitochondria and attempted to extrapolate these results back to the muscle, in vivo. Kinetic analysis was conducted to evaluate the dose-response effect of Ca(2+) on the maximal velocity of oxidative phosphorylation (V(maxO)) and the ADP affinity. Force-flow analysis evaluated the interplay between energetic driving forces and flux to determine the conductance, or effective activity, of individual steps within oxidative phosphorylation. Measured driving forces [extramitochondrial phosphorylation potential (ΔG(ATP)), membrane potential, and redox states of NADH and cytochromes b(H), b(L), c(1), c, and a,a(3)] were compared with flux (oxygen consumption) at 37 °C; 840 nM Ca(2+) generated an ~2-fold increase in V(maxO) with no change in ADP affinity (~43 μM). Force-flow analysis revealed that Ca(2+) activation of V(maxO) was distributed throughout the oxidative phosphorylation reaction sequence. Specifically, Ca(2+) increased the conductance of Complex IV (2.3-fold), Complexes I and III (2.2-fold), ATP production/transport (2.4-fold), and fuel transport/dehydrogenases (1.7-fold). These data support the notion that Ca(2+) activates the entire muscle oxidative phosphorylation cascade, while extrapolation of these data to the exercising muscle predicts a significant role of Ca(2+) in maintaining cellular energy homeostasis.
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Affiliation(s)
- Brian Glancy
- Laboratory of Cardiac Energetics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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Boelens AD, Pradhan RK, Blomeyer CA, Camara AKS, Dash RK, Stowe DF. Extra-matrix Mg2+ limits Ca2+ uptake and modulates Ca2+ uptake-independent respiration and redox state in cardiac isolated mitochondria. J Bioenerg Biomembr 2013; 45:203-18. [PMID: 23456198 DOI: 10.1007/s10863-013-9500-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 01/24/2013] [Indexed: 12/20/2022]
Abstract
Cardiac mitochondrial matrix (m) free Ca(2+) ([Ca(2+)]m) increases primarily by Ca(2+) uptake through the Ca(2+) uniporter (CU). Ca(2+) uptake via the CU is attenuated by extra-matrix (e) Mg(2+) ([Mg(2+)]e). How [Ca(2+)]m is dynamically modulated by interacting physiological levels of [Ca(2+)]e and [Mg(2+)]e and how this interaction alters bioenergetics are not well understood. We postulated that as [Mg(2+)]e modulates Ca(2+) uptake via the CU, it also alters bioenergetics in a matrix Ca(2+)-induced and matrix Ca(2+)-independent manner. To test this, we measured changes in [Ca(2+)]e, [Ca(2+)]m, [Mg(2+)]e and [Mg(2+)]m spectrofluorometrically in guinea pig cardiac mitochondria in response to added CaCl2 (0-0.6 mM; 1 mM EGTA buffer) with/without added MgCl2 (0-2 mM). In parallel, we assessed effects of added CaCl2 and MgCl2 on NADH, membrane potential (ΔΨm), and respiration. We found that ≥0.125 mM MgCl2 significantly attenuated CU-mediated Ca(2+) uptake and [Ca(2+)]m. Incremental [Mg(2+)]e did not reduce initial Ca(2+)uptake but attenuated the subsequent slower Ca(2+) uptake, so that [Ca(2+)]m remained unaltered over time. Adding CaCl2 without MgCl2 to attain a [Ca(2+)]m from 46 to 221 nM enhanced state 3 NADH oxidation and increased respiration by 15 %; up to 868 nM [Ca(2+)]m did not additionally enhance NADH oxidation or respiration. Adding MgCl2 did not increase [Mg(2+)]m but it altered bioenergetics by its direct effect to decrease Ca(2+) uptake. However, at a given [Ca(2+)]m, state 3 respiration was incrementally attenuated, and state 4 respiration enhanced, by higher [Mg(2+)]e. Thus, [Mg(2+)]e without a change in [Mg(2+)]m can modulate bioenergetics independently of CU-mediated Ca(2+) transport.
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Affiliation(s)
- Age D Boelens
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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31
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Poburko D, Demaurex N. Regulation of the mitochondrial proton gradient by cytosolic Ca²⁺ signals. Pflugers Arch 2012; 464:19-26. [PMID: 22526460 DOI: 10.1007/s00424-012-1106-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 04/02/2012] [Indexed: 12/16/2022]
Abstract
Mitochondria convert the energy stored in carbohydrate and fat into ATP molecules that power enzymatic reactions within cells, and this process influences cellular calcium signals in several ways. By providing ATP to calcium pumps at the plasma and intracellular membranes, mitochondria power the calcium gradients that drive the release of Ca²⁺ from stores and the entry of Ca²⁺ across plasma membrane channels. By taking up and subsequently releasing calcium ions, mitochondria determine the spatiotemporal profile of cellular Ca²⁺ signals and the activity of Ca²⁺-regulated proteins, including Ca²⁺ entry channels that are themselves part of the Ca²⁺ circuitry. Ca²⁺ elevations in the mitochondrial matrix, in turn, activate Ca²⁺-dependent enzymes that boost the respiratory chain, increasing the ability of mitochondria to buffer calcium ions. Mitochondria are able to encode and decode Ca²⁺ signals because the respiratory chain generates an electrochemical gradient for protons across the inner mitochondrial membrane. This proton motive force (Δp) drives the activity of the ATP synthase and has both an electrical component, the mitochondrial membrane potential (ΔΨ(m)), and a chemical component, the mitochondrial proton gradient (ΔpH(m)). ΔΨ(m) contributes about 190 mV to Δp and drives the entry of Ca²⁺ across a recently identified Ca²⁺-selective channel known as the mitochondrial Ca²⁺ uniporter. ΔpH(m) contributes ~30 mV to Δp and is usually ignored or considered a minor component of mitochondria respiratory state. However, the mitochondrial proton gradient is an essential component of the chemiosmotic theory formulated by Peter Mitchell in 1961 as ΔpH(m) sustains the entry of substrates and metabolites required for the activity of the respiratory chain and drives the activity of electroneutral ion exchangers that allow mitochondria to maintain their osmolarity and volume. In this review, we summarize the mechanisms that regulate the mitochondrial proton gradient and discuss how thermodynamic concepts derived from measurements in purified mitochondria can be reconciled with our recent findings that mitochondria have high proton permeability in situ and that ΔpH(m) decreases during mitochondrial Ca²⁺ elevations.
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Affiliation(s)
- Damon Poburko
- Department of Biomedical Physiology & Kinesiology, Simon Fraser University, Vancouver, BC, Canada
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Abstract
Calcium is an important signaling molecule involved in the regulation of many cellular functions. The large free energy in the Ca(2+) ion membrane gradients makes Ca(2+) signaling inherently sensitive to the available cellular free energy, primarily in the form of ATP. In addition, Ca(2+) regulates many cellular ATP-consuming reactions such as muscle contraction, exocytosis, biosynthesis, and neuronal signaling. Thus, Ca(2+) becomes a logical candidate as a signaling molecule for modulating ATP hydrolysis and synthesis during changes in numerous forms of cellular work. Mitochondria are the primary source of aerobic energy production in mammalian cells and also maintain a large Ca(2+) gradient across their inner membrane, providing a signaling potential for this molecule. The demonstrated link between cytosolic and mitochondrial Ca(2+) concentrations, identification of transport mechanisms, and the proximity of mitochondria to Ca(2+) release sites further supports the notion that Ca(2+) can be an important signaling molecule in the energy metabolism interplay of the cytosol with the mitochondria. Here we review sites within the mitochondria where Ca(2+) plays a role in the regulation of ATP generation and potentially contributes to the orchestration of cellular metabolic homeostasis. Early work on isolated enzymes pointed to several matrix dehydrogenases that are stimulated by Ca(2+), which were confirmed in the intact mitochondrion as well as cellular and in vivo systems. However, studies in these intact systems suggested a more expansive influence of Ca(2+) on mitochondrial energy conversion. Numerous noninvasive approaches monitoring NADH, mitochondrial membrane potential, oxygen consumption, and workloads suggest significant effects of Ca(2+) on other elements of NADH generation as well as downstream elements of oxidative phosphorylation, including the F(1)F(O)-ATPase and the cytochrome chain. These other potential elements of Ca(2+) modification of mitochondrial energy conversion will be the focus of this review. Though most specific molecular mechanisms have yet to be elucidated, it is clear that Ca(2+) provides a balanced activation of mitochondrial energy metabolism that exceeds the alteration of dehydrogenases alone.
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Affiliation(s)
- Brian Glancy
- Laboratory of Cardiac Energetics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20817, USA
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Abstract
Opening of a large conductance channel in the inner mitochondrial membrane, known as the mitochondrial permeability transition (MPT) pore, has been shown to be a primary mediator of cell death in the heart subjected to ischemia-reperfusion injury. Inhibitors of the MPT have been shown to reduce cardiac ischemia-reperfusion injury. Furthermore, most cardioprotective strategies appear to reduce ischemic cell death either by reducing the triggers for the opening of the MPT, such as reducing calcium overload or reactive oxygen species, or by more direct inhibition of the MPT. This chapter focuses on key issues in the study of the MPT and provides some methods for measuring MPT opening in isolated mitochondria.
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Affiliation(s)
- Renee Wong
- Cardiac Physiology Section, Systems Biology Center, NHLBI, NIH, Bethesda, MD 20892, USA
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34
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On the properties of calcium-induced permeability transition in neonatal heart mitochondria. J Bioenerg Biomembr 2011; 43:757-64. [DOI: 10.1007/s10863-011-9401-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 11/09/2011] [Indexed: 10/15/2022]
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Haumann J, Dash RK, Stowe DF, Boelens AD, Beard DA, Camara AKS. Mitochondrial free [Ca2+] increases during ATP/ADP antiport and ADP phosphorylation: exploration of mechanisms. Biophys J 2010; 99:997-1006. [PMID: 20712982 DOI: 10.1016/j.bpj.2010.04.069] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 04/21/2010] [Accepted: 04/28/2010] [Indexed: 11/26/2022] Open
Abstract
ADP influx and ADP phosphorylation may alter mitochondrial free [Ca2+] ([Ca2+](m)) and consequently mitochondrial bioenergetics by several postulated mechanisms. We tested how [Ca2+](m) is affected by H2PO4(-) (P(i)), Mg2+, calcium uniporter activity, matrix volume changes, and the bioenergetic state. We measured [Ca2+](m), membrane potential, redox state, matrix volume, pH(m), and O2 consumption in guinea pig heart mitochondria with or without ruthenium red, carboxyatractyloside, or oligomycin, and at several levels of Mg2+ and P(i). Energized mitochondria showed a dose-dependent increase in [Ca2+](m) after adding CaCl2 equivalent to 20, 114, and 485 nM extramatrix free [Ca2+] ([Ca2+](e)); this uptake was attenuated at higher buffer Mg2+. Adding ADP transiently increased [Ca2+](m) up to twofold. The ADP effect on increasing [Ca2+](m) could be partially attributed to matrix contraction, but was little affected by ruthenium red or changes in Mg2+ or P(i). Oligomycin largely reduced the increase in [Ca2+](m) by ADP compared to control, and [Ca2+](m) did not return to baseline. Carboxyatractyloside prevented the ADP-induced [Ca2+](m) increase. Adding CaCl2 had no effect on bioenergetics, except for a small increase in state 2 and state 4 respiration at 485 nM [Ca2+](e). These data suggest that matrix ADP influx and subsequent phosphorylation increase [Ca2+](m) largely due to the interaction of matrix Ca2+ with ATP, ADP, P(i), and cation buffering proteins in the matrix.
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Affiliation(s)
- Johan Haumann
- Anesthesiology Research Laboratories, Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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36
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Stowe DF, Camara AKS. Mitochondrial reactive oxygen species production in excitable cells: modulators of mitochondrial and cell function. Antioxid Redox Signal 2009; 11:1373-414. [PMID: 19187004 PMCID: PMC2842133 DOI: 10.1089/ars.2008.2331] [Citation(s) in RCA: 341] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 01/12/2009] [Accepted: 01/13/2009] [Indexed: 12/14/2022]
Abstract
The mitochondrion is a major source of reactive oxygen species (ROS). Superoxide (O(2)(*-)) is generated under specific bioenergetic conditions at several sites within the electron-transport system; most is converted to H(2)O(2) inside and outside the mitochondrial matrix by superoxide dismutases. H(2)O(2) is a major chemical messenger that, in low amounts and with its products, physiologically modulates cell function. The redox state and ROS scavengers largely control the emission (generation scavenging) of O(2)(*-). Cell ischemia, hypoxia, or toxins can result in excess O(2)(*-) production when the redox state is altered and the ROS scavenger systems are overwhelmed. Too much H(2)O(2) can combine with Fe(2+) complexes to form reactive ferryl species (e.g., Fe(IV) = O(*)). In the presence of nitric oxide (NO(*)), O(2)(*-) forms the reactant peroxynitrite (ONOO(-)), and ONOOH-induced nitrosylation of proteins, DNA, and lipids can modify their structure and function. An initial increase in ROS can cause an even greater increase in ROS and allow excess mitochondrial Ca(2+) entry, both of which are factors that induce cell apoptosis and necrosis. Approaches to reduce excess O(2)(*-) emission include selectively boosting the antioxidant capacity, uncoupling of oxidative phosphorylation to reduce generation of O(2)(*-) by inducing proton leak, and reversibly inhibiting electron transport. Mitochondrial cation channels and exchangers function to maintain matrix homeostasis and likely play a role in modulating mitochondrial function, in part by regulating O(2)(*-) generation. Cell-signaling pathways induced physiologically by ROS include effects on thiol groups and disulfide linkages to modify posttranslationally protein structure to activate/inactivate specific kinase/phosphatase pathways. Hypoxia-inducible factors that stimulate a cascade of gene transcription may be mediated physiologically by ROS. Our knowledge of the role played by ROS and their scavenging systems in modulation of cell function and cell death has grown exponentially over the past few years, but we are still limited in how to apply this knowledge to develop its full therapeutic potential.
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Affiliation(s)
- David F Stowe
- Anesthesiology Research Laboratories, Department of Anesthesiology, The Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
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Walsh C, Barrow S, Voronina S, Chvanov M, Petersen OH, Tepikin A. Modulation of calcium signalling by mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1374-82. [PMID: 19344663 DOI: 10.1016/j.bbabio.2009.01.007] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2008] [Revised: 01/12/2009] [Accepted: 01/13/2009] [Indexed: 02/07/2023]
Abstract
In this review we will attempt to summarise the complex and sometimes contradictory effects that mitochondria have on different forms of calcium signalling. Mitochondria can influence Ca(2+) signalling indirectly by changing the concentration of ATP, NAD(P)H, pyruvate and reactive oxygen species - which in turn modulate components of the Ca(2+) signalling machinery i.e. buffering, release from internal stores, influx from the extracellular solution, uptake into cellular organelles and extrusion by plasma membrane Ca(2+) pumps. Mitochondria can directly influence the calcium concentration in the cytosol of the cell by importing Ca(2+) via the mitochondrial Ca(2+) uniporter or transporting Ca(2+) from the interior of the organelle into the cytosol by means of Na+/Ca(2+) or H+/Ca(2+) exchangers. Considerable progress in understanding the relationship between Ca(2+) signalling cascades and mitochondrial physiology has been accumulated over the last few years due to the development of more advanced optical techniques and electrophysiological approaches.
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Affiliation(s)
- Ciara Walsh
- Department of Physiology, School of Biomedical Sciences, The University of Liverpool, Crown Street, Liverpool L69 3BX, UK
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38
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Divalent metal ions tune the self-splicing reaction of the yeast mitochondrial group II intron Sc.ai5γ. J Biol Inorg Chem 2008; 13:1025-36. [DOI: 10.1007/s00775-008-0390-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Accepted: 05/14/2008] [Indexed: 11/25/2022]
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39
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Chang DTW, Reynolds IJ. Mitochondrial trafficking and morphology in healthy and injured neurons. Prog Neurobiol 2006; 80:241-68. [PMID: 17188795 DOI: 10.1016/j.pneurobio.2006.09.003] [Citation(s) in RCA: 170] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Revised: 09/14/2006] [Accepted: 09/18/2006] [Indexed: 12/21/2022]
Abstract
Mitochondria are the primary generators of ATP and are important regulators of intracellular calcium homeostasis. These organelles are dynamically transported along lengthy neuronal processes, presumably for appropriate distribution to cellular regions of high metabolic demand and elevated intracellular calcium, such as synapses. The removal of damaged mitochondria that produce harmful reactive oxygen species and promote apoptosis is also thought to be mediated by transport of mitochondria to autophagosomes. Mitochondrial trafficking is therefore important for maintaining neuronal and mitochondrial health while cessation of movement may lead to neuronal and mitochondrial dysfunction. Mitochondrial morphology is also dynamic and is remodeled during neuronal injury and disease. Recent studies reveal different manifestations and mechanisms of impaired mitochondrial movement and altered morphology in injured neurons. These are likely to cause varied courses toward neuronal degeneration and death. The goal of this review is to provide an appreciation of the full range of mitochondrial function, morphology and trafficking, and the critical role these parameters play in neuronal physiology and pathophysiology.
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Affiliation(s)
- Diane T W Chang
- Medical Scientist Training Program, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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McCarron JG, Chalmers S, Bradley KN, MacMillan D, Muir TC. Ca2+ microdomains in smooth muscle. Cell Calcium 2006; 40:461-93. [PMID: 17069885 DOI: 10.1016/j.ceca.2006.08.010] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Accepted: 08/23/2006] [Indexed: 02/03/2023]
Abstract
In smooth muscle, Ca(2+) controls diverse activities including cell division, contraction and cell death. Of particular significance in enabling Ca(2+) to perform these multiple functions is the cell's ability to localize Ca(2+) signals to certain regions by creating high local concentrations of Ca(2+) (microdomains), which differ from the cytoplasmic average. Microdomains arise from Ca(2+) influx across the plasma membrane or release from the sarcoplasmic reticulum (SR) Ca(2+) store. A single Ca(2+) channel can create a microdomain of several micromolar near (approximately 200 nm) the channel. This concentration declines quickly with peak rates of several thousand micromolar per second when influx ends. The high [Ca(2+)] and the rapid rates of decline target Ca(2+) signals to effectors in the microdomain with rapid kinetics and enable the selective activation of cellular processes. Several elements within the cell combine to enable microdomains to develop. These include the brief open time of ion channels, localization of Ca(2+) by buffering, the clustering of ion channels to certain regions of the cell and the presence of membrane barriers, which restrict the free diffusion of Ca(2+). In this review, the generation of microdomains arising from Ca(2+) influx across the plasma membrane and the release of the ion from the SR Ca(2+) store will be discussed and the contribution of mitochondria and the Golgi apparatus as well as endogenous modulators (e.g. cADPR and channel binding proteins) will be considered.
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Affiliation(s)
- John G McCarron
- Department of Physiology and Pharmacology, University of Strathclyde, SIPBS, Glasgow, UK.
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Liang A, Du Y, Wang K, Lin B. Quantitative investigation of the interaction between granulocyte-macrophage colony-stimulating factor and heparin by capillary zone electrophoresis. J Sep Sci 2006; 29:1637-41. [PMID: 16922281 DOI: 10.1002/jssc.200600084] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The interactions between granulocyte-macrophage colony-stimulating factor (GM-CSF) and heparin or low-molecular weight heparin (LMWH) were studied by CZE. It was found that GM-CSF could bind to both heparin and LMWH. The binding constants were calculated from Scatchard regression to be (6.5 +/- 0.8) x 10(5)/M and (11.2 +/- 0.7) x 10(5)/M, respectively. The specificity of the interaction between GM-CSF and heparin was also studied by employing another sulfated K carrageenan oligosaccharide as a control. Results showed that K carrageenan oligosaccharide could not interact with GM-CSF, indicating that GM-CSF could specifically interact with heparin.
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Affiliation(s)
- Aiye Liang
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
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Terhzaz S, Southall TD, Lilley KS, Kean L, Allan AK, Davies SA, Dow JAT. Differential gel electrophoresis and transgenic mitochondrial calcium reporters demonstrate spatiotemporal filtering in calcium control of mitochondria. J Biol Chem 2006; 281:18849-58. [PMID: 16670086 DOI: 10.1074/jbc.m603002200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitochondria must adjust both their intracellular location and their metabolism in order to balance their output to the needs of the cell. Here we show by the proteomic technique of time series difference gel electrophoresis that a major result of neuroendocrine stimulation of the Drosophila renal tubule is an extensive remodeling of the mitochondrial matrix. By generating Drosophila that were transgenic for both luminescent and fluorescent mitochondrial calcium reporters, it was shown that mitochondrial calcium tracked the slow (minutes) but not the rapid (<1 s) changes in cytoplasmic calcium and that this resulted in both increased mitochondrial membrane polarization and elevated cellular ATP levels. The selective V-ATPase inhibitor, bafilomycin, further enhanced ATP levels, suggesting that the apical plasma membrane V-ATPase is a major consumer of ATP. Both the mitochondrial calcium signal and the increase in ATP were abolished by the mitochondrial calcium uniporter blocker Ru360. By using both mitochondrial calcium imaging and the potential sensing dye JC-1, the apical mitochondria of principal cells were found to be selectively responsive to neuropeptide signaling. As the ultimate target is the V-ATPase in the apical plasma membrane, this selective activation of mitochondria is clearly adaptive. The results highlight the dynamic nature and both spatial and temporal heterogeneity of calcium signaling possible in differentiated, organotypic cells and provide a new model for neuroendocrine control of V-ATPase.
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Affiliation(s)
- Selim Terhzaz
- Institute of Biomedical and Life Sciences, Division of Molecular Genetics, University of Glasgow, Glasgow G11 6NU, Scotland, UK
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Affiliation(s)
- Ernesto Carafoli
- Department of Biochemistry, University of Padova, Viale G. Colombo 3, 35121 Padua, Italy.
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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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45
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Kajimoto K, Daikoku T, Kita F, Yamazaki N, Kataoka M, Baba Y, Terada H, Shinohara Y. PCR-select subtraction for characterization of messages differentially expressed in brown compared with white adipose tissue. Mol Genet Metab 2003; 80:255-61. [PMID: 14567975 DOI: 10.1016/j.ymgme.2003.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
To understand the energy metabolism occurring in brown adipose tissue (BAT), we subtracted the messages expressed in white adipose tissue (WAT) from those in BAT. Thereby we succeeded in identifying 37 cDNA clones as being significantly expressed in BAT but not in WAT. Of these, 24 clones were found to code for mitochondrial proteins. Since BAT is well known to have a higher mitochondrial content than WAT, these results would seem to reflect simply the differences in mitochondrial content between BAT and WAT. To examine this possibility, we next measured the amount of mitochondrial DNA (mtDNA) in various rat tissues. As a result, the mtDNA copy number per cell was found to be markedly different among the tissues analyzed, and the highest value of about 5.3x10(4) copies per cell was observed with the rat brain. BAT showed a value similar to that of brain, but this value was only about 3.5-fold higher than that for WAT. Since observed differences in mitochondrial content between BAT and WAT was smaller than those observed with transcript levels of proteins, we conclude that the observed differences in the transcript levels of certain proteins between BAT and WAT reflect the functional differences between BAT and WAT, and do not reflect the differences in mitochondrial content between BAT and WAT.
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Affiliation(s)
- Kazuaki Kajimoto
- Faculty of Pharmaceutical Sciences, University of Tokushima, Shomachi-1, Tokushima 770-8505, Japan
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García-Pérez C, Pardo JP, Martínez F. Ca(2+) modulates respiratory and steroidogenic activities of human term placental mitochondria. Arch Biochem Biophys 2002; 405:104-111. [PMID: 12176063 DOI: 10.1016/s0003-9861(02)00274-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We investigated the effects of calcium on the oxidative metabolism and steroidogenic activity of human term placental mitochondria. Submicromolar Ca(2+) concentrations stimulated state 3 oxygen consumption with 2-oxoglutarate and isocitrate and activated the 2-oxoglutarate and the NAD-isocitrate dehydrogenases by diminishing their Michaelis-Menten constants. Ca(2+) inhibited NADP-isocitrate dehydrogenase (NADP-ICDH) and the synthesis of progesterone. The NADP-ICDH maximal velocity was threefold higher than that of NAD-ICDH and had a threefold lower K(m) for isocitrate than NAD-ICDH. Isocitrate but not malate or 2-oxoglutarate supported progesterone synthesis. Calcium inhibition of progesterone synthesis was observed with isocitrate but not with malate or 2-oxoglutarate. Tight regulation of NADP-isocitrate dehydrogenase by calcium ions suggests that this enzyme plays an important role in placental mitochondrial metabolism.
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Affiliation(s)
- Cecilia García-Pérez
- Departamento de Bioqui;mica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70-159, DF 04510, México, Mexico
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Brennan L, Shine A, Hewage C, Malthouse JPG, Brindle KM, McClenaghan N, Flatt PR, Newsholme P. A nuclear magnetic resonance-based demonstration of substantial oxidative L-alanine metabolism and L-alanine-enhanced glucose metabolism in a clonal pancreatic beta-cell line: metabolism of L-alanine is important to the regulation of insulin secretion. Diabetes 2002; 51:1714-21. [PMID: 12031957 DOI: 10.2337/diabetes.51.6.1714] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Early experiments indicated that islet beta-cells substantially metabolized L-alanine but that insulin secretion was largely unaffected by the amino acid. It was subsequently demonstrated using more intricate studies that L-alanine is a strong stimulus to insulin secretion in the presence of glucose in normal rodent islets and beta-cell lines. Using (13)C nuclear magnetic resonance (NMR), we have demonstrated substantial oxidative metabolism of L-alanine by the clonal beta-cell line BRIN-BD11, with time-dependent increases in production of cellular glutamate and aspartate. Stimulatory effects of L-alanine on insulin secretion were attenuated by the inhibition of beta-cell oxidative phosphorylation using oligomycin. Additionally, we detected substantial production of lactate, alanine, and glutamate from glucose (16.7 mmol/l) after 60 min. On addition of 10 mmol/l L-alanine to a stimulus of 16.7 mmol/l glucose, the utilization rate of glucose increased approximately 2.4-fold. L-Alanine dramatically enhanced NMR-measurable aspects of glucose metabolism (both oxidative and nonoxidative). The enhanced rate of entry of glucose-derived pyruvate into the tricarboxylic acid (TCA) cycle in the presence of alanine may have stimulated rates of generation of key metabolites, including ATP, which affect the insulin secretory process. Thus L-alanine metabolism, in addition to the enhancing effect on glucose metabolism, contributes to the stimulatory effects of this amino acid on insulin secretion in vitro.
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Affiliation(s)
- Lorraine Brennan
- Department of Biochemistry, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
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Abstract
The role of metabolism in the generation of plasma insulin oscillations was investigated by simultaneous in vivo recordings of oxygen tension (pO(2)) in the endocrine and exocrine pancreas and portal blood insulin concentrations in the anesthetized rat. At the start of the experiment, the blood glucose concentration of seven rats was 6.2 +/- 0.1 mmol/l and the arterial blood pressure was 116 +/- 5 mmHg. These values did not differ from those obtained at the end of the experiment. Islet pO(2) was measured by impaling superficially located islets with a miniaturized Clark electrode. The pO(2) measurements revealed slow (0.21 +/- 0.03 min(-1)) with superimposed rapid (3.1 +/- 0.3 min(-1)) oscillations. The average pO(2) was 39 +/- 5 mmHg. Simultaneous recordings of pO(2) in the exocrine pancreas were significantly lower (16 +/- 6 mmHg), but showed a slow and a rapid oscillatory activity with similar frequencies as seen in the endocrine pancreas. Corresponding measurements of portal insulin concentrations revealed insulin oscillations at a frequency of 0.22 +/- 0.02 min(-1). The results are the first in vivo recordings of an oscillatory islet parameter with a frequency corresponding to that of plasma insulin oscillations; they support a primary role of metabolic oscillations in the induction of plasma insulin oscillations.
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Affiliation(s)
- Peter Bergsten
- Department of Medical Cell, Uppsala University, Uppsala, Sweden.
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Abstract
An experiment performed in London nearly 120 years ago, which by today's standards would be considered unacceptably sloppy, marked the beginning of the calcium (Ca(2+)) signaling saga. Sidney Ringer [Ringer, S. (1883) J. Physiol. 4, 29-43] was studying the contraction of isolated rat hearts. In earlier experiments, Ringer had suspended them in a saline medium for which he admitted to having used London tap water, which is hard: The hearts contracted beautifully. When he proceeded to replace the tap water with distilled water, he made a startling finding: The beating of the hearts became progressively weaker, and stopped altogether after about 20 min. To maintain contraction, he found it necessary to add Ca(2+) salts to the suspension medium. Thus, Ringer had serendipitously discovered that Ca(2+), hitherto exclusively considered as a structural element, was active in a tissue that has nothing to do with bone or teeth, and performed there a completely novel function: It carried the signal that initiated heart contraction. It was a landmark observation, which should have immediately aroused wide interest. Unexpectedly, however, for decades it attracted no particular attention. Occasionally, farsighted pioneers argued forcefully for a messenger role of Ca(2+), offering compelling experimental evidence. Among them, one could quote L. V. Heilbrunn [Heilbrunn, L. V. (1940) Physiol. Zool. 13, 88-94], who contracted frog muscle fibers by applying Ca(2+) salts to their cut ends, but not to their surfaces. Heilbrunn correctly concluded that Ca(2+) had diffused from the cut ends to the internal contractile elements to elicit their contraction. One could also quote K. Bailey [Bailey, K. (1942) Biochem. J. 36, 121-139], who showed that the ATPase activity of myosin was strongly activated by Ca(2+) (but not by Mg(2+)), and concluded that the liberation of Ca(2+) in the neighborhood of the myosin controlled muscle contraction. Clearly, enough evidence was there, but only a handful of people had the vision to see it and to foresee its far-reaching implications. Perhaps no better example of clairvoyance can be offered than the quip by O. Loewy in 1959: "Ja Kalzium, das ist alles!"
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Affiliation(s)
- Ernesto Carafoli
- Department of Biochemistry, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy.
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50
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Bergsten P. Role of oscillations in membrane potential, cytoplasmic Ca2+, and metabolism for plasma insulin oscillations. Diabetes 2002; 51 Suppl 1:S171-6. [PMID: 11815477 DOI: 10.2337/diabetes.51.2007.s171] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A model for the relationship between ionic and metabolic oscillations and plasma insulin oscillations is presented. It is argued that the pancreatic beta-cell in vivo displays two intrinsic frequencies that are important for the regulation of plasma insulin oscillations. The rapid oscillatory activity (2--7 oscillations [osc] per minute), which is evident in both ionic and metabolic events, causes the required elevation in cytoplasmic Ca(2+) concentration ([Ca(2+)](i)) for the exocytosis of insulin granules. This activity is important for regulation of the amplitude of plasma insulin oscillations. The frequency of the rapid oscillatory ionic activities is regulated by glucose and allows the beta-cell to respond in an analogous way, with gradual changes in [Ca(2+)](i) and insulin release in response to the alterations in glucose concentration. The slower oscillatory activity (0.2--0.4 osc/min), which is evident in the metabolism of the beta-cell, has a frequency corresponding to the frequency observed in plasma insulin oscillations. The frequency is not affected by changes in the glucose concentration. This activity is suggested to generate energy in a pulsatile fashion, which sets the frequency of the plasma insulin oscillations. It is proposed that the slow oscillations in [Ca(2+)](i) observed in vitro are a manifestation of the metabolic oscillations and do not represent an in vivo phenomenon.
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Affiliation(s)
- Peter Bergsten
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden.
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