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Fang X, Zhang Y, Wu H, Wang H, Miao R, Wei J, Zhang Y, Tian J, Tong X. Mitochondrial regulation of diabetic endothelial dysfunction: Pathophysiological links. Int J Biochem Cell Biol 2024; 170:106569. [PMID: 38556159 DOI: 10.1016/j.biocel.2024.106569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 03/27/2024] [Accepted: 03/27/2024] [Indexed: 04/02/2024]
Abstract
Micro- and macrovascular complications frequently occur in patients with diabetes, with endothelial dysfunction playing a key role in the development and progression of the complications. For the early diagnosis and optimal treatment of vascular complications associated with diabetes, it is imperative to comprehend the cellular and molecular mechanisms governing the function of diabetic endothelial cells. Mitochondria function as crucial sensors of environmental and cellular stress regulating endothelial cell viability, structural integrity and function. Impaired mitochondrial quality control mechanisms and mitochondrial dysfunction are the main features of endothelial damage. Hence, targeted mitochondrial therapy is considered promising novel therapeutic options in vascular complications of diabetes. In this review, we focus on the mitochondrial functions in the vascular endothelial cells and the pathophysiological role of mitochondria in diabetic endothelial dysfunction, aiming to provide a reference for related drug development and clinical diagnosis and treatment.
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Affiliation(s)
- Xinyi Fang
- Institute of Metabolic Diseases, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China; Graduate College, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Yanjiao Zhang
- Institute of Metabolic Diseases, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Haoran Wu
- Graduate College, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Han Wang
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Runyu Miao
- Institute of Metabolic Diseases, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China; Graduate College, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Jiahua Wei
- Graduate College, Changchun University of Chinese Medicine, Jilin 130117, China
| | - Yuxin Zhang
- Institute of Metabolic Diseases, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Jiaxing Tian
- Institute of Metabolic Diseases, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
| | - Xiaolin Tong
- Institute of Metabolic Diseases, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
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2
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Kulovic-Sissawo A, Tocantins C, Diniz MS, Weiss E, Steiner A, Tokic S, Madreiter-Sokolowski CT, Pereira SP, Hiden U. Mitochondrial Dysfunction in Endothelial Progenitor Cells: Unraveling Insights from Vascular Endothelial Cells. BIOLOGY 2024; 13:70. [PMID: 38392289 PMCID: PMC10886154 DOI: 10.3390/biology13020070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/18/2024] [Accepted: 01/19/2024] [Indexed: 02/24/2024]
Abstract
Endothelial dysfunction is associated with several lifestyle-related diseases, including cardiovascular and neurodegenerative diseases, and it contributes significantly to the global health burden. Recent research indicates a link between cardiovascular risk factors (CVRFs), excessive production of reactive oxygen species (ROS), mitochondrial impairment, and endothelial dysfunction. Circulating endothelial progenitor cells (EPCs) are recruited into the vessel wall to maintain appropriate endothelial function, repair, and angiogenesis. After attachment, EPCs differentiate into mature endothelial cells (ECs). Like ECs, EPCs are also susceptible to CVRFs, including metabolic dysfunction and chronic inflammation. Therefore, mitochondrial dysfunction of EPCs may have long-term effects on the function of the mature ECs into which EPCs differentiate, particularly in the presence of endothelial damage. However, a link between CVRFs and impaired mitochondrial function in EPCs has hardly been investigated. In this review, we aim to consolidate existing knowledge on the development of mitochondrial and endothelial dysfunction in the vascular endothelium, place it in the context of recent studies investigating the consequences of CVRFs on EPCs, and discuss the role of mitochondrial dysfunction. Thus, we aim to gain a comprehensive understanding of mechanisms involved in EPC deterioration in relation to CVRFs and address potential therapeutic interventions targeting mitochondrial health to promote endothelial function.
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Affiliation(s)
- Azra Kulovic-Sissawo
- Perinatal Research Laboratory, Department of Obstetrics and Gynaecology, Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria
- Research Unit Early Life Determinants (ELiD), Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria
| | - Carolina Tocantins
- Perinatal Research Laboratory, Department of Obstetrics and Gynaecology, Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria
- Research Unit Early Life Determinants (ELiD), Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria
- CNC-UC-Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-504 Coimbra, Portugal
- Doctoral Programme in Experimental Biology and Biomedicine (PDBEB), Institute for Interdisciplinary Research (IIIUC), University of Coimbra, 3004-531 Coimbra, Portugal
| | - Mariana S Diniz
- Perinatal Research Laboratory, Department of Obstetrics and Gynaecology, Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria
- Research Unit Early Life Determinants (ELiD), Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria
- CNC-UC-Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-504 Coimbra, Portugal
- Doctoral Programme in Experimental Biology and Biomedicine (PDBEB), Institute for Interdisciplinary Research (IIIUC), University of Coimbra, 3004-531 Coimbra, Portugal
| | - Elisa Weiss
- Perinatal Research Laboratory, Department of Obstetrics and Gynaecology, Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria
- Research Unit Early Life Determinants (ELiD), Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria
| | - Andreas Steiner
- Perinatal Research Laboratory, Department of Obstetrics and Gynaecology, Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria
- Research Unit Early Life Determinants (ELiD), Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria
| | - Silvija Tokic
- Research Unit of Analytical Mass Spectrometry, Cell Biology and Biochemistry of Inborn Errors of Metabolism, Department of Paediatrics and Adolescent Medicine, Medical University of Graz, Auenbruggerplatz 34, 8036 Graz, Austria
| | - Corina T Madreiter-Sokolowski
- Division of Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria
| | - Susana P Pereira
- CNC-UC-Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-504 Coimbra, Portugal
- Laboratory of Metabolism and Exercise (LaMetEx), Research Centre in Physical Activity, Health and Leisure (CIAFEL), Laboratory for Integrative and Translational Research in Population Health (ITR), Faculty of Sports, University of Porto, 4200-450 Porto, Portugal
| | - Ursula Hiden
- Perinatal Research Laboratory, Department of Obstetrics and Gynaecology, Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria
- Research Unit Early Life Determinants (ELiD), Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria
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Kirkman DL, Robinson AT, Rossman MJ, Seals DR, Edwards DG. Mitochondrial contributions to vascular endothelial dysfunction, arterial stiffness, and cardiovascular diseases. Am J Physiol Heart Circ Physiol 2021; 320:H2080-H2100. [PMID: 33834868 PMCID: PMC8163660 DOI: 10.1152/ajpheart.00917.2020] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 03/12/2021] [Accepted: 04/05/2021] [Indexed: 12/11/2022]
Abstract
Cardiovascular disease (CVD) affects one in three adults and remains the leading cause of death in America. Advancing age is a major risk factor for CVD. Recent plateaus in CVD-related mortality rates in high-income countries after decades of decline highlight a critical need to identify novel therapeutic targets and strategies to mitigate and manage the risk of CVD development and progression. Vascular dysfunction, characterized by endothelial dysfunction and large elastic artery stiffening, is independently associated with an increased CVD risk and incidence and is therefore an attractive target for CVD prevention and management. Vascular mitochondria have emerged as an important player in maintaining vascular homeostasis. As such, age- and disease-related impairments in mitochondrial function contribute to vascular dysfunction and consequent increases in CVD risk. This review outlines the role of mitochondria in vascular function and discusses the ramifications of mitochondrial dysfunction on vascular health in the setting of age and disease. The adverse vascular consequences of increased mitochondrial-derived reactive oxygen species, impaired mitochondrial quality control, and defective mitochondrial calcium cycling are emphasized, in particular. Current evidence for both lifestyle and pharmaceutical mitochondrial-targeted strategies to improve vascular function is also presented.
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Affiliation(s)
- Danielle L Kirkman
- Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, Virginia
| | | | - Matthew J Rossman
- Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - Douglas R Seals
- Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - David G Edwards
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware
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4
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Shemarova IV, Korotkov SM, Nesterov VP. Ca2+-Dependent
Mitochondrial Mechanisms of Cardioprotection. J EVOL BIOCHEM PHYS+ 2020. [DOI: 10.1134/s002209302004002x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Intracellular sodium elevation reprograms cardiac metabolism. Nat Commun 2020; 11:4337. [PMID: 32859897 PMCID: PMC7455741 DOI: 10.1038/s41467-020-18160-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/10/2020] [Indexed: 12/12/2022] Open
Abstract
Intracellular Na elevation in the heart is a hallmark of pathologies where both acute and chronic metabolic remodelling occurs. Here, we assess whether acute (75 μM ouabain 100 nM blebbistatin) or chronic myocardial Nai load (PLM3SA mouse) are causally linked to metabolic remodelling and whether the failing heart shares a common Na-mediated metabolic ‘fingerprint’. Control (PLMWT), transgenic (PLM3SA), ouabain-treated and hypertrophied Langendorff-perfused mouse hearts are studied by 23Na, 31P, 13C NMR followed by 1H-NMR metabolomic profiling. Elevated Nai leads to common adaptive metabolic alterations preceding energetic impairment: a switch from fatty acid to carbohydrate metabolism and changes in steady-state metabolite concentrations (glycolytic, anaplerotic, Krebs cycle intermediates). Inhibition of mitochondrial Na/Ca exchanger by CGP37157 ameliorates the metabolic changes. In silico modelling indicates altered metabolic fluxes (Krebs cycle, fatty acid, carbohydrate, amino acid metabolism). Prevention of Nai overload or inhibition of Na/Camito may be a new approach to ameliorate metabolic dysregulation in heart failure. The failing heart is characterised by both alterations in mitochondrial metabolism and an elevation of cytosolic sodium. Here, the authors use 23Na NMR and metabolic profiling to show these are related, and that elevation in intracellular Na reprograms cardiac substrate utilisation via effects on mitochondrial Na/Ca exchange.
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6
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Sanchez M, Lin Y, Yang CC, McQuary P, Rosa Campos A, Aza Blanc P, Wolf DA. Cross Talk between eIF2α and eEF2 Phosphorylation Pathways Optimizes Translational Arrest in Response to Oxidative Stress. iScience 2019; 20:466-480. [PMID: 31627132 PMCID: PMC6823656 DOI: 10.1016/j.isci.2019.09.031] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 06/14/2019] [Accepted: 09/23/2019] [Indexed: 01/26/2023] Open
Abstract
The cellular stress response triggers a cascade of events leading to transcriptional reprogramming and a transient inhibition of global protein synthesis, which is thought to be mediated by phosphorylation of eukaryotic initiation factor-2α (eIF2α). Using mouse embryonic fibroblasts (MEFs) and the fission yeast S. pombe, we report that rapid translational arrest and cell survival in response to hydrogen peroxide-induced oxidative stress do not rely on eIF2α kinases and eIF2α phosphorylation. Rather, H2O2 induces a block in elongation through phosphorylation of eukaryotic elongation factor 2 (eEF2). Kinetic and dose-response analyses uncovered cross talk between the eIF2α and eEF2 phosphorylation pathways, indicating that, in MEFs, eEF2 phosphorylation initiates the acute shutdown in translation, which is maintained by eIF2α phosphorylation. Our results challenge the common conception that eIF2α phosphorylation is the primary trigger of translational arrest in response to oxidative stress and point to integrated control that may facilitate the survival of cancer cells. Oxidative stress-induced translation arrest is independent of eIF2α phosphorylation Oxidative stress blocks translation elongation Oxidative stress triggers eEF2 kinase activation eEF2K KO cells are hypersensitive to oxidative stress
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Affiliation(s)
- Marisa Sanchez
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA.
| | - Yingying Lin
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research and Center for Stress Signaling Networks, Xiamen University, Xiamen 361102, China
| | - Chih-Cheng Yang
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Philip McQuary
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | | | - Pedro Aza Blanc
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Dieter A Wolf
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA; School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research and Center for Stress Signaling Networks, Xiamen University, Xiamen 361102, China.
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Weatherly LM, Nelson AJ, Shim J, Riitano AM, Gerson ED, Hart AJ, de Juan-Sanz J, Ryan TA, Sher R, Hess ST, Gosse JA. Antimicrobial agent triclosan disrupts mitochondrial structure, revealed by super-resolution microscopy, and inhibits mast cell signaling via calcium modulation. Toxicol Appl Pharmacol 2018; 349:39-54. [PMID: 29630968 DOI: 10.1016/j.taap.2018.04.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 03/22/2018] [Accepted: 04/04/2018] [Indexed: 01/15/2023]
Abstract
The antimicrobial agent triclosan (TCS) is used in products such as toothpaste and surgical soaps and is readily absorbed into oral mucosa and human skin. These and many other tissues contain mast cells, which are involved in numerous physiologies and diseases. Mast cells release chemical mediators through a process termed degranulation, which is inhibited by TCS. Investigation into the underlying mechanisms led to the finding that TCS is a mitochondrial uncoupler at non-cytotoxic, low-micromolar doses in several cell types and live zebrafish. Our aim was to determine the mechanisms underlying TCS disruption of mitochondrial function and of mast cell signaling. We combined super-resolution (fluorescence photoactivation localization) microscopy and multiple fluorescence-based assays to detail triclosan's effects in living mast cells, fibroblasts, and primary human keratinocytes. TCS disrupts mitochondrial nanostructure, causing mitochondria to undergo fission and to form a toroidal, "donut" shape. TCS increases reactive oxygen species production, decreases mitochondrial membrane potential, and disrupts ER and mitochondrial Ca2+ levels, processes that cause mitochondrial fission. TCS is 60 × more potent than the banned uncoupler 2,4-dinitrophenol. TCS inhibits mast cell degranulation by decreasing mitochondrial membrane potential, disrupting microtubule polymerization, and inhibiting mitochondrial translocation, which reduces Ca2+ influx into the cell. Our findings provide mechanisms for both triclosan's inhibition of mast cell signaling and its universal disruption of mitochondria. These mechanisms provide partial explanations for triclosan's adverse effects on human reproduction, immunology, and development. This study is the first to utilize super-resolution microscopy in the field of toxicology.
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Affiliation(s)
- Lisa M Weatherly
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, USA; Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA
| | - Andrew J Nelson
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Juyoung Shim
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA
| | - Abigail M Riitano
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA
| | - Erik D Gerson
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA
| | - Andrew J Hart
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA
| | | | - Timothy A Ryan
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA
| | - Roger Sher
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, USA
| | - Samuel T Hess
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, USA; Department of Physics and Astronomy, University of Maine, Orono, ME, USA.
| | - Julie A Gosse
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, USA; Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA.
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Lane RK, Hilsabeck T, Rea SL. The role of mitochondrial dysfunction in age-related diseases. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1847:1387-400. [PMID: 26050974 PMCID: PMC10481969 DOI: 10.1016/j.bbabio.2015.05.021] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 05/20/2015] [Accepted: 05/29/2015] [Indexed: 02/08/2023]
Abstract
The aging process is accompanied by the onset of disease and a general decline in wellness. Insights into the aging process have revealed a number of cellular hallmarks of aging, among these epigenetic alterations, loss of proteostasis, mitochondrial dysfunction, cellular senescence, and stem cell exhaustion. Mitochondrial dysfunction increasingly appears to be a common factor connecting several of these hallmarks, driving the aging process and afflicting tissues throughout the body. Recent research has uncovered a much more complex involvement of mitochondria in the cell than has previously been appreciated and revealed novel ways in which mitochondrial defects feed into disease pathology. In this review we evaluate ways in which problems in mitochondria contribute to disease beyond the well-known mechanisms of oxidative stress and bioenergetic deficits, and we predict the direction that mitochondrial disease research will take in years to come.
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Affiliation(s)
- Rebecca K Lane
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, TX 78245, USA
| | - Tyler Hilsabeck
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, TX 78245, USA; The University of Texas, San Antonio, TX 78249, USA
| | - Shane L Rea
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, TX 78245, USA; Department of Physiology, University of Texas Health Science Center, San Antonio, TX 78229, USA.
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9
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Mitochondrial dysfunctions during progression of dystrophic cardiomyopathy. Cell Calcium 2015; 58:186-95. [PMID: 25975620 DOI: 10.1016/j.ceca.2015.04.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 04/09/2015] [Accepted: 04/12/2015] [Indexed: 01/26/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a progressive muscle disease with severe cardiac complications. It is believed that cellular oxidative stress and augmented Ca(2+) signaling drives the development of cardiac pathology. Some mitochondrial and metabolic dysfunctions have also been reported. Here we investigate cellular mechanisms responsible for impaired mitochondrial metabolism in dystrophic cardiomyopathy at early stages of the disease. We employed electrophysiological and imaging techniques to study mitochondrial structure and function in cardiomyocytes from mdx mice, an animal model of DMD. Here we show that mitochondrial matrix was progressively oxidized in myocytes isolated from mdx mice. Moreover, an abrupt increase in workload resulted in significantly more pronounced oxidation of mitochondria in dystrophic cells. Electron micrographs revealed a gradually increased number of damaged mitochondria in mdx myocytes. Degradation in mitochondrial structure was correlated with progressive increase in mitochondrial Ca(2+) sequestration and mitochondrial depolarization, despite a substantial and persistent elevation in resting cytosolic sodium levels. Treatment of mdx cells with cyclosporine A, an inhibitor of mitochondrial permeability transition pore (mPTP), shifted both resting and workload-dependent mitochondrial redox state to the levels recorded in control myocytes. It also significantly reduced workload dependent depolarization of mitochondrial membrane in dystrophic cardiomyocytes. Overall, our studies highlight age dependent deterioration of mitochondrial function in dystrophic cardiomyocytes, which seems to be associated with excessive opening of mPTP due to oxidative stress and cellular Ca(2+) overload.
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Konradi J, Mollenhauer M, Baldus S, Klinke A. Redox-sensitive mechanisms underlying vascular dysfunction in heart failure. Free Radic Res 2015; 49:721-42. [DOI: 10.3109/10715762.2015.1027200] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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11
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Fonseca ACR, Resende R, Cardoso SM, Pereira CF. The role of proteotoxic stress in vascular dysfunction in the pathogenesis of Alzheimer’s disease. ENDOPLASMIC RETICULUM STRESS IN DISEASES 2015. [DOI: 10.1515/ersc-2015-0005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractAlzheimer’s disease (AD) is the principal cause of dementia in the elderly; however, its prevalence is increasing due to the fact that current pharmaceuticals used to manage the symptoms are not capable of preventing, halting, or reversing disease progression. In the last decade, evidence has accumulated to support the hypothesis that a primary cerebral vascular dysfunction initiates the cascade of events that leads to neuronal injury and the subsequent cognitive decline observed in AD. The mechanisms underlying these vascular defects and their relationship with neurodegeneration are still poorly understood however. It is pathologically known that cerebrovascular dysfunctions can induce the deposition of amyloid-β (Aβ), an amyloidogenic and toxic peptide that in turn causes cerebrovascular degeneration. Mammalian cells regulate proteostasis and the functioning of intracellular organelles through diverse mechanisms such as the Unfolded Protein Response, the Ubiquitin-Proteasome System and autophagy; however, when these mechanisms cannot compensate for perturbations in homeostasis, the cell undergoes programmed death via apoptosis. This review summarizes recent studies that together correlate the deregulation of protein quality control pathways with dysfunction of vascular endothelial cells of the brain in AD, thus supporting the hypothesis that it is the vicious, progressive failure of the proteostatic network and endothelial activation that underlies the cerebrovascular changes that symptomize AD.
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Abstract
Endothelial cell dysfunction is the hallmark of every cardiovascular disease/condition, including atherosclerosis and ischemia/reperfusion injury. Fluid shear stress acting on the vascular endothelium is known to regulate cell homeostasis. Altered hemodynamics is thought to play a causative role in endothelial dysfunction. The dysfunction is associated with/preceded by mitochondrial oxidative stress. Studies by our group and others have shown that the form and/or function of the mitochondrial network are affected when endothelial cells are exposed to shear stress in the absence or presence of additional physicochemical stimuli. The present review will summarize the current knowledge on the interconnections among intracellular Ca2+ - nitric oxide - mitochondrial reactive oxygen species, mitochondrial fusion/fission, autophagy/mitophagy, and cell apoptosis vs. survival. More specifically, it will list the evidence on potential regulation of the above intracellular species and processes by the fluid shear stress acting on the endothelium under either physiological flow conditions or during reperfusion (following a period of ischemia). Understanding how the local hemodynamics affects mitochondrial physiology and the cell redox state may lead to development of novel therapeutic strategies for prevention or treatment of the endothelial dysfunction and, hence, of cardiovascular disease.
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13
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Fonseca ACRG, Moreira PI, Oliveira CR, Cardoso SM, Pinton P, Pereira CF. Amyloid-beta disrupts calcium and redox homeostasis in brain endothelial cells. Mol Neurobiol 2014; 51:610-22. [PMID: 24833600 DOI: 10.1007/s12035-014-8740-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/05/2014] [Indexed: 11/25/2022]
Abstract
In Alzheimer's disease, the accumulation of amyloid-beta (Aβ) in the brain occurs in the parenchyma and cerebrovasculature. Several evidences support that the neuronal demise is potentiated by vascular alterations in the early stages of the disease, but the mechanisms responsible for the dysfunction of brain endothelial cells that underlie these cerebrovascular changes are unknown. Using rat brain microvascular endothelial cells, we found that short-term treatment with a toxic dose of Aβ1-40 inhibits the Ca(2+) refill and retention ability of the endoplasmic reticulum and enhances the mitochondrial and cytosolic response to adenosine triphosphate (ATP)-stimulated endoplasmic reticulum Ca(2+) release. Upon prolonged Aβ1-40 exposure, Ca(2+) homeostasis was restored concomitantly with a decrease in the levels of proteins involved in its regulation operating at the plasma membrane, endoplasmic reticulum, and mitochondria. Along with perturbations in Ca(2+) regulation, an early increase in the levels of oxidants and a decrease in the ratio between reduced and oxidized glutathione were observed in Aβ1-40-treated endothelial cells. Under these conditions, the nuclear levels of oxidative stress-related transcription factors, namely, hypoxia-inducible factor 1α and nuclear factor (erythroid-derived 2)-related factor 2, were enhanced as well as the protein levels of target genes. In conclusion, Aβ1-40 affects several mechanisms involved in Ca(2+) homeostasis and impairs the redox homeostasis simultaneously with stimulation of protective stress responses in brain endothelial cells. However, the imbalance between cell death and survival pathways leads to endothelial dysfunction that in turn contributes to cerebrovascular impairment in Alzheimer's disease.
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Affiliation(s)
- Ana Catarina R G Fonseca
- Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal
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14
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Tang X, Luo YX, Chen HZ, Liu DP. Mitochondria, endothelial cell function, and vascular diseases. Front Physiol 2014; 5:175. [PMID: 24834056 PMCID: PMC4018556 DOI: 10.3389/fphys.2014.00175] [Citation(s) in RCA: 247] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 04/16/2014] [Indexed: 12/20/2022] Open
Abstract
Mitochondria are perhaps the most sophisticated and dynamic responsive sensing systems in eukaryotic cells. The role of mitochondria goes beyond their capacity to create molecular fuel and includes the generation of reactive oxygen species, the regulation of calcium, and the activation of cell death. In endothelial cells, mitochondria have a profound impact on cellular function under both healthy and diseased conditions. In this review, we summarize the basic functions of mitochondria in endothelial cells and discuss the roles of mitochondria in endothelial dysfunction and vascular diseases, including atherosclerosis, diabetic vascular dysfunction, pulmonary artery hypertension, and hypertension. Finally, the potential therapeutic strategies to improve mitochondrial function in endothelial cells and vascular diseases are also discussed, with a focus on mitochondrial-targeted antioxidants and calorie restriction.
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Affiliation(s)
- Xiaoqiang Tang
- State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, China
| | - Yu-Xuan Luo
- State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, China
| | - Hou-Zao Chen
- State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, China
| | - De-Pei Liu
- State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, China
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15
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Wang Y, Tabas I. Emerging roles of mitochondria ROS in atherosclerotic lesions: causation or association? J Atheroscler Thromb 2014; 21:381-90. [PMID: 24717761 DOI: 10.5551/jat.23929] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Mitochondrial-derived reactive oxygen species (mtROS) is one of the major sources of cellular ROS, and excessive mtROS is associated with atherosclerosis progression in both human and mouse models. This review aims to summarize the most recent studies showing the existence, the causes and pathological consequences of excessive mtROS in atherosclerosis. Despite numerous association and causation studies demonstrating the importance of mtROS in atherosclerosis progression, the failure of antioxidant therapy in human randomized clinical trials demands more definitive, cell-type specific investigations. Better mechanistic understanding of mtROS in atherosclerosis may lead to more effective therapeutic strategies.
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16
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Bai Y, Zhao X, Qi C, Wang L, Cheng Z, Liu M, Liu J, Yang D, Wang S, Chai T. Effects of chromium picolinate on the viability of chick embryo fibroblast. Hum Exp Toxicol 2013; 33:403-13. [DOI: 10.1177/0960327113499042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Chromium picolinate (CrPic), which is used as a nutritional supplement and to treat type 2 diabetes, has gained much attention because of its cytotoxicity. This study evaluated the effects of CrPic on the viability of the chick embryo fibroblast (CEF) using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, morphological detection, and flow cytometry. The results show that lower concentrations of CrPic (8 and 16 μM) did not damage CEF viability ( p > 0.05). However, higher CrPic concentrations (400 and 600 μM) indicated a highly significant effect on the production of intracellular reactive oxygen species, alteration of mitochondrial membrane potential, intracellular calcium ion concentration, and the apoptosis rate ( p < 0.01), contrary to lower CrPic concentrations (8 and 16 μM) and control group. Moreover, apoptotic morphological changes induced by these processes in CEF were confirmed using Hoechst 33258 staining. Cell death induced by higher concentrations of CrPic was caused by an apoptotic and a necrotic mechanism, whereas the main mechanism of oxidative stress-induced mitochondrial dysfunction was apoptotic death.
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Affiliation(s)
- Y Bai
- College of Veterinary Medicine, Research Center for Animal Disease Control Engineering Shandong Province, Shandong Agricultural University, Tai’an, China
| | - X Zhao
- College of Veterinary Medicine, Research Center for Animal Disease Control Engineering Shandong Province, Shandong Agricultural University, Tai’an, China
| | - C Qi
- Central Hospital of Tai’an City, Tai’an, Shandong, China
| | - L Wang
- College of Veterinary Medicine, Research Center for Animal Disease Control Engineering Shandong Province, Shandong Agricultural University, Tai’an, China
| | - Z Cheng
- College of Veterinary Medicine, Research Center for Animal Disease Control Engineering Shandong Province, Shandong Agricultural University, Tai’an, China
| | - M Liu
- College of Veterinary Medicine, Research Center for Animal Disease Control Engineering Shandong Province, Shandong Agricultural University, Tai’an, China
| | - J Liu
- College of Veterinary Medicine, Research Center for Animal Disease Control Engineering Shandong Province, Shandong Agricultural University, Tai’an, China
| | - D Yang
- College of Veterinary Medicine, Research Center for Animal Disease Control Engineering Shandong Province, Shandong Agricultural University, Tai’an, China
| | - S Wang
- College of Veterinary Medicine, Research Center for Animal Disease Control Engineering Shandong Province, Shandong Agricultural University, Tai’an, China
| | - T Chai
- Sino-German Cooperative Research Centre for Zoonosis of Animal Origin of Shandong Province, Tai’an, China
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17
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Abstract
In contrast to their role in cell types with higher energy demands, mitochondria in endothelial cells primarily function in signaling cellular responses to environmental cues. This article provides an overview of key aspects of mitochondrial biology in endothelial cells, including subcellular location, biogenesis, dynamics, autophagy, reactive oxygen species production and signaling, calcium homeostasis, regulated cell death, and heme biosynthesis. In each section, we introduce key concepts and then review studies showing the importance of that mechanism to endothelial control of vasomotor tone, angiogenesis, and/or inflammatory activation. We particularly highlight the small number of clinical and translational studies that have investigated each mechanism in human subjects. Finally, we review interventions that target different aspects of mitochondrial function and their effects on endothelial function. The ultimate goal of such research is the identification of new approaches for therapy. The reviewed studies make it clear that mitochondria are important in endothelial physiology and pathophysiology. A great deal of work will be needed, however, before mitochondria-directed therapies are available for the prevention and treatment of cardiovascular disease.
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Affiliation(s)
- Matthew A Kluge
- Evans Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118, USA
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18
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Abstract
Reactive oxygen species (ROS) have been associated with various human diseases, and considerable attention has been paid to investigate their physiological effects. Various ROS are synthesized in the mitochondria and accumulate in the cytoplasm if the cellular antioxidant defense mechanism fails. The critical balance of this ROS synthesis and antioxidant defense systems is termed the redox system of the cell. Various cardiovascular diseases have also been affected by redox to different degrees. ROS have been indicated as both detrimental and protective, via different cellular pathways, for cardiac myocyte functions, electrophysiology, and pharmacology. Mostly, the ROS functions depend on the type and amount of ROS synthesized. While the literature clearly indicates ROS effects on cardiac contractility, their effects on cardiac excitability are relatively under appreciated. Cardiac excitability depends on the functions of various cardiac sarcolemal or mitochondrial ion channels carrying various depolarizing or repolarizing currents that also maintain cellular ionic homeostasis. ROS alter the functions of these ion channels to various degrees to determine excitability by affecting the cellular resting potential and the morphology of the cardiac action potential. Thus, redox balance regulates cardiac excitability, and under pathological regulation, may alter action potential propagation to cause arrhythmia. Understanding how redox affects cellular excitability may lead to potential prophylaxis or treatment for various arrhythmias. This review will focus on the studies of redox and cardiac excitation.
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Affiliation(s)
- Nitin T Aggarwal
- Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison, WI 53792, USA
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19
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Groschner LN, Waldeck-Weiermair M, Malli R, Graier WF. Endothelial mitochondria--less respiration, more integration. Pflugers Arch 2012; 464:63-76. [PMID: 22382745 PMCID: PMC3387498 DOI: 10.1007/s00424-012-1085-z] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 02/11/2012] [Indexed: 12/21/2022]
Abstract
Lining the inner surface of the circulatory system, the vascular endothelium accomplishes a vast variety of specialized functions. Even slight alterations of these functions are implicated in the development of certain cardiovascular diseases that represent major causes of morbidity and mortality in developed countries. Endothelial mitochondria are essential to the functional integrity of the endothelial cell as they integrate a wide range of cellular processes including Ca²⁺ handling, redox signaling and apoptosis, all of which are closely interrelated. Growing evidence supports the notion that impairment of mitochondrial signaling in the endothelium is an early event and a causative factor in the development of diseases such as atherosclerosis or diabetic complications. In this review, we want to outline the significance of mitochondria in both physiology and pathology of the vascular endothelium.
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Affiliation(s)
- Lukas N. Groschner
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21/III, 8010 Graz, Austria
| | - Markus Waldeck-Weiermair
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21/III, 8010 Graz, Austria
| | - Roland Malli
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21/III, 8010 Graz, Austria
| | - Wolfgang F. Graier
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21/III, 8010 Graz, Austria
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20
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Spät A, Fülöp L, Szanda G. The role of mitochondrial Ca(2+) and NAD(P)H in the control of aldosterone secretion. Cell Calcium 2012; 52:64-72. [PMID: 22364774 DOI: 10.1016/j.ceca.2012.01.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 01/25/2012] [Accepted: 01/27/2012] [Indexed: 01/03/2023]
Abstract
The mineralocorticoid hormone aldosterone is synthesized in the zona glomerulosa of the adrenal cortex. Glomerulosa cells respond to the physiological stimuli, elevated extracellular [K(+)] and angiotensin II, with an intracellular Ca(2+) signal. Cytosolic Ca(2+) facilitates the transport of the steroid-precursor cholesterol to mitochondria and, after a few hours, it also induces the transcription of aldosterone synthase. Therefore, the cytosolic Ca(2+) signal is regarded as the most important short and long-term mediator of aldosterone secretion. However, cytosolic Ca(2+) is also taken up by mitochondria and, in turn, the mitochondrial Ca(2+) response activates mitochondrial dehydrogenases resulting in stimulation of respiration and increase in reduced pyridine nucleotides. Since both cholesterol side-chain cleavage and all of the hydroxylation steps of steroid synthesis require NADPH as a cofactor, the importance of cytosolic Ca(2+) - mitochondrial Ca(2+) coupling and of appropriate NADPH supply in respect to hormone production can be assumed. However, the importance of the mitochondrial factors has been neglected so far. Here, after summarizing earlier findings we provide new results obtained through modifying mitochondrial Ca(2+) uptake by knocking down p38 MAPK or OPA1 and overexpressing S100G, supporting the notion that mitochondrial Ca(2+) and reduced pyridine nucleotides are facilitating factors for both basal and stimulated steroid production.
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Affiliation(s)
- András Spät
- Department of Physiology, Faculty of Medicine, Semmelweis University, Hungary.
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21
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Barsukova AG, Bourdette D, Forte M. Mitochondrial calcium and its regulation in neurodegeneration induced by oxidative stress. Eur J Neurosci 2011; 34:437-47. [PMID: 21722208 PMCID: PMC3221651 DOI: 10.1111/j.1460-9568.2011.07760.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A proposed mechanism of neuronal death associated with a variety of neurodegenerative diseases is the response of neurons to oxidative stress and consequent cytosolic Ca(2+) overload. One hypothesis is that cytosolic Ca(2+) overload leads to mitochondrial Ca(2+) overload and prolonged opening of the permeability transition pore (PTP), resulting in mitochondrial dysfunction. Elimination of cyclophilin D (CyPD), a key regulator of the PTP, results in neuroprotection in a number of murine models of neurodegeneration in which oxidative stress and high cytosolic Ca(2+) have been implicated. However, the effects of oxidative stress on the interplay between cytosolic and mitochondrial Ca(2+) in adult neurons and the role of the CyPD-dependent PTP in these dynamic processes have not been examined. Here, using primary cultured cerebral cortical neurons from adult wild-type (WT) mice and mice missing cyclophilin D (CyPD-KO), we directly assess cytosolic and mitochondrial Ca(2+) , as well as ATP levels, during oxidative stress. Our data demonstrate that during acute oxidative stress mitochondria contribute to neuronal Ca(2+) overload by release of their Ca(2+) stores. This result contrasts with the prevailing view of mitochondria as a buffer of cytosolic Ca(2+) under stress conditions. In addition, we show that CyPD deficiency reverses the release of mitochondrial Ca(2+) , leading to lower of cytosolic Ca(2+) levels, attenuation of the decrease in cytosolic and mitochondrial ATP, and a significantly higher viability of adult CyPD-knockout neurons following exposure of neurons oxidative stress. The study offers a first insight into the mechanism underlying CyPD-dependent neuroprotection during oxidative stress.
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Affiliation(s)
| | - Dennis Bourdette
- Dept. of Neurology, Oregon Health & Science University
- Neurology Service, VA Medical Center, Portland, OR 97239
| | - Michael Forte
- Vollum Institute, Oregon Health & Science University
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22
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Shabala S, Bækgaard L, Shabala L, Fuglsang AT, Cuin TA, Nemchinov LG, Palmgren MG. Endomembrane Ca2+-ATPases play a significant role in virus-induced adaptation to oxidative stress. PLANT SIGNALING & BEHAVIOR 2011; 6:1053-6. [PMID: 21633195 PMCID: PMC3257794 DOI: 10.4161/psb.6.7.15634] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 03/24/2011] [Indexed: 05/04/2023]
Abstract
Although the role of Ca2+ influx channels in oxidative stress signaling and cross-tolerance in plants is well established, little is known about the role of active Ca2+ efflux systems in this process. In our recent paper, we reported Potato Virus X (PVX)-induced acquired resistance to oxidative stress in Nicotiana benthamiana and showed the critical role of plasma membrane Ca2+/H+ exchangers in this process. The current study continues this research. Using biochemical and electrophysiological approaches, we reveal that both endomembrane P2A and P2B Ca2+-ATPases play significant roles in adaptive responses to oxidative stress by removing excessive Ca2+ from the cytosol, and that their functional expression is significantly altered in PVX-inoculated plants. These findings highlight the crucial role of Ca2+ efflux systems in acquired tolerance to oxidative stress and open up prospects for practical applications in agriculture, after in-depth comprehension of the fundamental mechanisms involved in common responses to environmental factors at the genomic, cellular and organismal levels.
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Affiliation(s)
- Sergey Shabala
- School of Agricultural Science, University of Tasmania, Hobart, TAS, Australia.
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23
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Shabala S, Baekgaard L, Shabala L, Fuglsang A, Babourina O, Palmgren MG, Cuin TA, Rengel Z, Nemchinov LG. Plasma membrane Ca²+ transporters mediate virus-induced acquired resistance to oxidative stress. PLANT, CELL & ENVIRONMENT 2011; 34:406-17. [PMID: 21062316 DOI: 10.1111/j.1365-3040.2010.02251.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
This paper reports the phenomenon of acquired cross-tolerance to oxidative stress in plants and investigates the activity of specific Ca²+ transport systems mediating this phenomenon. Nicotiana benthamiana plants were infected with Potato virus X (PVX) and exposed to oxidative [either ultraviolet (UV-C) or H₂O₂] stress. Plant adaptive responses were assessed by the combined application of a range of electrophysiological (non-invasive microelectrode ion flux measurements), biochemical (Ca²+- and H+-ATPase activity), imaging (fluorescence lifetime imaging measurements of changes in intracellular Ca²+ concentrations), pharmacological and cytological transmission electrone microscopy techniques. Virus-infected plants had a better ability to control UV-induced elevations in cytosolic-free Ca²+ and prevent structural and functional damage of chloroplasts. Taken together, our results suggest a high degree of crosstalk between UV and pathogen-induced oxidative stresses, and highlight the crucial role of Ca²+ efflux systems in acquired resistance to oxidative stress in plants.
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Affiliation(s)
- Sergey Shabala
- School of Agricultural Science, Menzies Research Institute, University of Tasmania, Private Bag 54, Hobart, Tas 7001, Australia.
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24
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Li W, Shi YH, Yang RL, Cui J, Xiao Y, Le GW. Reactive oxygen species serve as signals mediating glucose-stimulated somatostatin secretion from cultured rat gastric primary D-cells. Free Radic Res 2010; 44:614-23. [PMID: 20370561 DOI: 10.3109/10715761003713549] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Somatostatin plays an important role in glucose homeostasis. It is normally secreted in response to glucose and ATP generation is believed to be the key transduction signal of glucose-stimulated somatostatin secretion (GSSS). However, in the present study, in cultured rat gastric primary D-cells, GSSS was accompanied by increases in cellular reactive oxygen species (ROS). GSSS is dependent on the cellular ROS and independently of the ATP production linked to glucose metabolism. The antioxidant, alpha-lipoic acid or catalase inhibitor, 3-aminotriazole can influence the intracellular calcium concentration and abolish or further elevate GSSS. It is suggested that ROS production may serve as a signal modulating the necessary Ca(2+) recruitment for GSSS. Since somatostatin is thought to exert broad regulatory functions on gastrointestinal physiology and nutrient intake, the interaction with ROS may lead to potential targets for mediating nutrition and energy homeostasis.
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Affiliation(s)
- Wu Li
- State Key Lab of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu Province, PR China
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25
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Steinert JR, Wyatt AW, Jacob R, Mann GE. Redox modulation of Ca2+ signaling in human endothelial and smooth muscle cells in pre-eclampsia. Antioxid Redox Signal 2009; 11:1149-63. [PMID: 19125611 DOI: 10.1089/ars.2008.2303] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Pre-eclampsia (PE) is a leading cause of maternal hypertension in pregnancy and is associated with fetal growth restriction, premature birth, and fetal and maternal mortality. Activation and dysfunction of the maternal and fetal endothelium in PE appears to be a consequence of increased oxidative stress, resulting from elevated levels of circulating lipid peroxides. Accumulating evidence implicates reactive oxygen species (ROS) in the pathogenesis of vascular dysfunction in PE, perhaps involving a disturbance in intracellular Ca(2+) signaling. Several ion-transport pathways are highly sensitive to oxidative stress, and the resulting modulation of ion transport by ROS will affect intracellular Ca(2+) homeostasis. We review the evidence that changes in ion transport induced by ROS may be linked with abnormalities in Ca(2+)-mediated signal transduction, leading to endothelial and smooth muscle dysfunction in maternal and fetal circulations in PE. As dysregulation of Ca(2+) signaling in fetal umbilical endothelial cells is maintained in culture and embryonic, fetal, and postnatal development is affected by the cellular redox state, we hypothesize that impaired redox signaling in PE may influence "programming" of the fetal cardiovascular system and endothelial function in adulthood.
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Affiliation(s)
- Joern R Steinert
- Cardiovascular Division, School of Medicine, King's College London, London, England
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26
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Gandhi S, Wood-Kaczmar A, Yao Z, Plun-Favreau H, Deas E, Klupsch K, Downward J, Latchman DS, Tabrizi SJ, Wood NW, Duchen MR, Abramov AY. PINK1-associated Parkinson's disease is caused by neuronal vulnerability to calcium-induced cell death. Mol Cell 2009; 33:627-38. [PMID: 19285945 PMCID: PMC2724101 DOI: 10.1016/j.molcel.2009.02.013] [Citation(s) in RCA: 508] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 09/01/2008] [Accepted: 02/20/2009] [Indexed: 12/21/2022]
Abstract
Mutations in PINK1 cause autosomal recessive Parkinson's disease. PINK1 is a mitochondrial kinase of unknown function. We investigated calcium homeostasis and mitochondrial function in PINK1-deficient mammalian neurons. We demonstrate physiologically that PINK1 regulates calcium efflux from the mitochondria via the mitochondrial Na(+)/Ca(2+) exchanger. PINK1 deficiency causes mitochondrial accumulation of calcium, resulting in mitochondrial calcium overload. We show that calcium overload stimulates reactive oxygen species (ROS) production via NADPH oxidase. ROS production inhibits the glucose transporter, reducing substrate delivery and causing impaired respiration. We demonstrate that impaired respiration may be restored by provision of mitochondrial complex I and II substrates. Taken together, reduced mitochondrial calcium capacity and increased ROS lower the threshold of opening of the mitochondrial permeability transition pore (mPTP) such that physiological calcium stimuli become sufficient to induce mPTP opening in PINK1-deficient cells. Our findings propose a mechanism by which PINK1 dysfunction renders neurons vulnerable to cell death.
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Affiliation(s)
- Sonia Gandhi
- Department of Molecular Neuroscience, Institute of Neurology, Queen Square, London WC1N 3BG, UK
- Medical Molecular Biology Unit, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Alison Wood-Kaczmar
- Department of Molecular Neuroscience, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Zhi Yao
- Department of Molecular Neuroscience, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Helene Plun-Favreau
- Department of Molecular Neuroscience, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Emma Deas
- Department of Molecular Neuroscience, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Kristina Klupsch
- Cancer Research UK, 44 Lincoln's Inn Fields, London WC2A 3PX, UK
| | - Julian Downward
- Cancer Research UK, 44 Lincoln's Inn Fields, London WC2A 3PX, UK
| | - David S. Latchman
- Medical Molecular Biology Unit, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
- Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Sarah J. Tabrizi
- Department of Neurodegenerative Disease, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Nicholas W. Wood
- Department of Molecular Neuroscience, Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Michael R. Duchen
- Department of Physiology, University College London, London WC1E 6BT, UK
| | - Andrey Y. Abramov
- Department of Molecular Neuroscience, Institute of Neurology, Queen Square, London WC1N 3BG, UK
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27
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Castaldo P, Cataldi M, Magi S, Lariccia V, Arcangeli S, Amoroso S. Role of the mitochondrial sodium/calcium exchanger in neuronal physiology and in the pathogenesis of neurological diseases. Prog Neurobiol 2008; 87:58-79. [PMID: 18952141 DOI: 10.1016/j.pneurobio.2008.09.017] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Revised: 09/23/2008] [Accepted: 09/29/2008] [Indexed: 11/26/2022]
Abstract
In neurons, as in other excitable cells, mitochondria extrude Ca(2+) ions from their matrix in exchange with cytosolic Na(+) ions. This exchange is mediated by a specific transporter located in the inner mitochondrial membrane, the mitochondrial Na(+)/Ca(2+) exchanger (NCX(mito)). The stoichiometry of NCX(mito)-operated Na(+)/Ca(2+) exchange has been the subject of a long controversy, but evidence of an electrogenic 3 Na(+)/1 Ca(2+) exchange is increasing. Although the molecular identity of NCX(mito) is still undetermined, data obtained in our laboratory suggest that besides the long-sought and as yet unfound mitochondrial-specific NCX, the three isoforms of plasmamembrane NCX can contribute to NCX(mito) in neurons and astrocytes. NCX(mito) has a role in controlling neuronal Ca(2+) homeostasis and neuronal bioenergetics. Indeed, by cycling the Ca(2+) ions captured by mitochondria back to the cytosol, NCX(mito) determines a shoulder in neuronal [Ca(2+)](c) responses to neurotransmitters and depolarizing stimuli which may then outlast stimulus duration. This persistent NCX(mito)-dependent Ca(2+) release has a role in post-tetanic potentiation, a form of short-term synaptic plasticity. By controlling [Ca(2+)](m) NCX(mito) regulates the activity of the Ca(2+)-sensitive enzymes pyruvate-, alpha-ketoglutarate- and isocitrate-dehydrogenases and affects the activity of the respiratory chain. Convincing experimental evidence suggests that supraphysiological activation of NCX(mito) contributes to neuronal cell death in the ischemic brain and, in epileptic neurons coping with seizure-induced ion overload, reduces the ability to reestablish normal ionic homeostasis. These data suggest that NCX(mito) could represent an important target for the development of new neurological drugs.
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Affiliation(s)
- P Castaldo
- Department of Neuroscience, Section of Pharmacology, Università Politecnica delle Marche, Via Tronto 10/A, 60020 Torrette di Ancona, Ancona, Italy
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28
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Abstract
Disturbances in vascular function contribute to the development of several diseases of increasing prevalence and thereby contribute significantly to human mortality and morbidity. Atherosclerosis, diabetes, heart failure, and ischemia with attendant reperfusion injury share many of the same risk factors, among the most important being oxidative stress and alterations in the blood concentrations of compounds that influence oxidative stress, such as oxidized low-density lipoprotein. In this review, we focus on endothelial cells: cells in the frontline against these disturbances. Because ATP supplies in endothelial cells are relatively independent of mitochondrial oxidative pathways, the mitochondria of endothelial cells have been somewhat neglected. However, they are emerging as agents with diverse roles in modulating the dynamics of intracellular calcium and the generation of reactive oxygen species and nitric oxide. The mitochondria may also constitute critical "targets" of oxidative stress, because survival of endothelial cells can be compromised by opening of the mitochondrial permeability transition pore or by mitochondrial pathways of apoptosis. In addition, evidence suggests that endothelial mitochondria may play a "reconnaissance" role. For example, although the exact mechanism remains obscure, endothelial mitochondria may sense levels of oxygen in the blood and relay this information to cardiac myocytes as well as modulating the vasodilatory response mediated by endothelial nitric oxide.
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Affiliation(s)
- Sean M Davidson
- The Hatter Cardiovascular Institute, Department of Medicine, Royal Free and University College Medical School, London, United Kingdom.
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29
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Franklin RA, Rodriguez-Mora OG, Lahair MM, McCubrey JA. Activation of the calcium/calmodulin-dependent protein kinases as a consequence of oxidative stress. Antioxid Redox Signal 2006; 8:1807-17. [PMID: 16987033 DOI: 10.1089/ars.2006.8.1807] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Oxygen radicals have diverse effects on cells. In many cases, exposure to reactive oxygen intermediates (ROI) can induce cell death. Conversely, there is also evidence that suggests oxygen radicals can activate signaling pathways that are thought to prevent cell death. In this review, the authors discuss the finding that hydrogen peroxide and ROI-generating treatments trigger the activation of the calcium/calmodulin-dependent kinases (CaM-kinases), and the potential role this activation has in preventing apoptosis. Evidence is presented that CaM-kinase activation occurs by both calcium dependent- and independent-pathways in response to ROIs. In addition, the idea is discussed that ROIs have the potential to lead to the phosphorylation of calmodulin and through this mechanism potentiate the activation of the CaM-kinases. The concept that inhibition of the CaM-kinases as a mechanism to sensitize cells to the damaging effects of ROIs is also presented. Contrasting these studies, evidence is presented that exposure of the CaM-kinases directly to hydrogen peroxide also has the apparent ability to inhibit their activity.
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Affiliation(s)
- Richard A Franklin
- Department of Microbiology and Immunology, and the Leo W. Jenkins Cancer Center, Brody School of Medicine at East Carolina University, Greenville, North Carolina 27834, USA
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30
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Martínez-Burgos MA, Granados MP, González A, Rosado JA, Yago MD, Salido GM, Martínez-Victoria E, Mañas M, Pariente JA. Involvement of ryanodine-operated channels in tert-butylhydroperoxide-evoked Ca2+ mobilisation in pancreatic acinar cells. ACTA ACUST UNITED AC 2006; 209:2156-64. [PMID: 16709917 DOI: 10.1242/jeb.02250] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Reactive oxygen species and related oxidative damage have been implicated in the initiation of acute pancreatitis, a disease characterised in its earliest stages by disruption of intracellular Ca2+ homeostasis. The present study was carried out in order to establish the effect of the organic pro-oxidant, tert-butylhydroperoxide (tBHP), on the mobilisation of intracellular Ca2+ stores in isolated rat pancreatic acinar cells and the mechanisms underlying this effect. Cytosolic free Ca2+ concentrations ([Ca2+]c) were monitored using a digital microspectrofluorimetric system in fura-2 loaded cells. In the presence of normal extracellular Ca2+ concentrations ([Ca2+]o), perfusion of pancreatic acinar cells with 1 mmol l-1 tBHP caused a slow sustained increase in [Ca2+]c. This increase was also observed in a nominally Ca2+-free medium, indicating a release of Ca2+ from intracellular stores. Pretreatment of cells with tBHP abolished the typical Ca2+ response of both the physiological agonist CCK-8 (1 nmol l-1) and thapsigargin (TPS, 1 micromol l-1), an inhibitor of the SERCA pump, in the absence of extracellular Ca2+. Similar results were observed with carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP, 0.5 micromol l-1), a mitochondrial uncoupler. In addition, depletion of either agonist-sensitive Ca2+ pools by CCK-8 or TPS or mitochondrial Ca2+ pools by FCCP were unable to prevent the tBHP-induced Ca2+ release. By contrast, simultaneous administration of TPS and FCCP clearly abolished the tBHP-induced Ca2+ release. These results show that tBHP releases Ca2+ from agonist-sensitive intracellular stores and from mitochondria. On the other hand, simultaneous application of FCCP and of 2-aminoethoxydiphenylborane (2-APB), a blocker of IP3-mediated Ca2+ release, was unable to suppress the increase in [Ca2+]c induced by tBHP, while the application of 50 micromol l-1 of ryanodine (which is able to block the ryanodine channels) inhibits tBHP-evoked Ca2+ mobilisation. These findings indicate that tBHP releases Ca2+ from non-mitochondrial Ca2+ pools through ryanodine channels.
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Affiliation(s)
- María A Martínez-Burgos
- Institute of Nutrition and Food Technology, Department of Physiology, University of Granada, C/Ramón y Cajal, 4. 18071, Granada, Spain.
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Koncz P, Szanda G, Rajki A, Spät A. Reactive oxygen species, Ca2+ signaling and mitochondrial NAD(P)H level in adrenal glomerulosa cells. Cell Calcium 2006; 40:347-57. [PMID: 16765442 DOI: 10.1016/j.ceca.2006.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Revised: 03/30/2006] [Accepted: 04/12/2006] [Indexed: 12/21/2022]
Abstract
The acute effects of ultraviolet light, the superoxide-generating xanthine-xanthine oxidase system and H(2)O(2) to on calcium signaling and mitochondrial pyridine nucleotide metabolism were investigated in rat glomerulosa cells. UV light induced the formation of superoxide, that, similar to exogenously applied superoxide and H(2)O(2), decreased the level of mitochondrial NAD(P)H. Free radical scavengers antagonized this effect of UV light. Extracellularly generated superoxide elicited Ca(2+) transients and inhibited angiotensin II-induced cytoplasmic Ca(2+) signaling. Low intensity UV light did not affect basal [Ca(2+)] and failed to influence Ca(2+) signaling induced by depolarization or store depletion. UV light of the same low power reduced both cytoplasmic and mitochondrial Ca(2+) signals induced by angiotensin II. The lack of UV effect on inositol phosphate formation indicates that the inhibition of cytoplasmic Ca(2+) signaling is due to reduced Ca(2+) release from InsP(3)-sensitive stores. Decreased mitochondrial Ca(2+) uptake may be attributed to UV-induced perturbation of the perimitochondrial microdomain.
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Affiliation(s)
- Péter Koncz
- Department of Physiology, Faculty of Medicine, Semmelweis University and Laboratory of Cellular and Molecular Physiology, Hungarian Academy of Sciences, P.O. Box 259, H-1444 Budapest, Hungary
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Zuppini A, Navazio L, Mariani P. Endoplasmic reticulum stress-induced programmed cell death in soybean cells. J Cell Sci 2004; 117:2591-8. [PMID: 15159454 DOI: 10.1242/jcs.01126] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
In animal cells, the endoplasmic reticulum may participate in programmed cell death by sensing and transducing apoptotic signals. In an attempt to analyze the role of the endoplasmic reticulum in plant programmed cell death we investigated the effect of cyclopiazonic acid, a specific blocker of plant endoplasmic reticulum-type IIA Ca2+-pumps, in soybean cells. Cyclopiazonic acid treatment elicited endoplasmic reticulum stress and a biphasic increase in cytosolic Ca2+ concentration, followed by the induction of a cell death program. Cyclopiazonic acid-induced programmed cell death occurred with accumulation of H2O2, cytochrome c release from mitochondria, caspase 9- and caspase 3-like protease activation, cytoplasmic shrinkage and chromatin condensation. Chelation of cytosolic Ca2+ with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (acetoxymethil ester) failed to inhibit cyclopiazonic acid-induced cell death. Taken together, our results provide evidence for a role of the endoplasmic reticulum and mitochondria in regulating cyclopiazonic acid-induced programmed cell death in soybean cells, probably via a cross-talk between the two organelles.
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Affiliation(s)
- Anna Zuppini
- Dipartimento di Biologia, Università di Padova, 35131 Padova, Italy.
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33
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Zuliani T, Duval R, Jayat C, Schnébert S, André P, Dumas M, Ratinaud MH. Sensitive and reliable JC-1 and TOTO-3 double staining to assess mitochondrial transmembrane potential and plasma membrane integrity: interest for cell death investigations. Cytometry A 2003; 54:100-8. [PMID: 12879456 DOI: 10.1002/cyto.a.10059] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Apoptosis is currently studied by flow cytometry with mitochondrial membrane potential (Deltapsimt) and membrane integrity fluorochromes. Rhodamine 123 and DiOC6(3) remain controversial to identify cells displaying a low Deltapsimt. JC-1 constitutes a good Deltapsimt indicator, due to a fluorescence shift from green to orange emission, according to the increase in Deltapsimt. Nevertheless, it is not feasible to analyze it simultaneously with propidium iodide. Among available fluorescent probes, TOTO-3 seems to be a good candidate for double staining with JC-1. METHODS Cell death of HaCaT cells was induced by H2O2 and FasL. Samples were stained with DiOC6(3)/IP or JC-1/TOTO-3 then analyzed by flow cytometry. Results were supported by confocal microscopy analyses of mitochondrial membrane potential. Moreover, cell morphology was determined on the sorted subpopulations defined on the basis of staining (JC-1 versus TOTO-3). RESULTS We found that JC-1 is a more efficient mitochondrial probe than DiOC6(3). After stress induction, the fluorescence level of JC-1 and TOTO-3 clearly defined three fluorescent subpopulations, respectively: (1) JC-1high and TOTO-3low, (2) JC-1low and TOTO-3medium, and (3) JC-1low and TOTO-3high. Their morphologic aspects after cell sorting indicated that they corresponded to three functional states (intact, apoptotic, and necrotic cells), and data were supported by caspase activity measurements. CONCLUSIONS We propose a reliable and efficient staining, with JC-1 and TOTO-3 to discriminate three functional cellular states: intact, apoptotic, and necrotic/late apoptotic cells by flow cytometry.
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Affiliation(s)
- Thomas Zuliani
- LVMH-Recherches, Laboratoires R & D, Branche Parfums-Cosmétiques, Saint-Jean de Braye Cedex, France.
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34
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Bishara NB, Dunlop ME, Murphy TV, Darby IA, Sharmini Rajanayagam MA, Hill MA. Matrix protein glycation impairs agonist-induced intracellular Ca2+ signaling in endothelial cells. J Cell Physiol 2002; 193:80-92. [PMID: 12209883 DOI: 10.1002/jcp.10153] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Studies have shown diabetes to be associated with alterations in composition of extracellular matrix and that such proteins modulate signal transduction. The present studies examined if non-enzymatic glycation of fibronectin or a mixed matrix preparation (EHS) alters endothelial cell Ca(2+) signaling following agonist stimulation. Endothelial cells were cultured from bovine aorta and rat heart. To glycate proteins, fibronectin (10 microg/ml), or EHS (2.5 mg/ml) were incubated (37 degrees C, 30 days) with 0.5 M glucose-6-phosphate. Matrix proteins were coated onto cover slips after which cells (10(5) cells/ml) were plated and allowed to adhere for 16 h. For measurement of intracellular Ca(2+), cells were loaded with fura 2 (2 microM) and fluorescence intensity monitored. Bovine cells on glycated EHS showed decreased ability for either ATP (10(-6) M) or bradykinin (10(-7) M) to increase Ca(2+) (i). In contrast, glycated fibronectin did not impair agonist-induced increases in Ca(2+) (i). In the absence of extracellular Ca(2+), ATP elicited a transient increase in Ca(2+) (i) consistent with intracellular release. Re-addition of Ca(2+) resulted in a secondary rise in Ca(2+) (i) indicative of store depletion-mediated Ca(2+) entry. Both phases of Ca(2+) mobilization were reduced in cells on glycated mixed matrix; however, as the ratio of the two components was similar in all cells, glycation appeared to selectively impair Ca(2+) release from intracellular stores. Thapsigargin treatment demonstrated an impaired ability of cells on glycated EHS to increase cytoplasmic Ca(2+) consistent with decreased endoplasmic reticulum Ca(2+) stores. Further support for Ca(2+) mobilization was provided by increased baseline IP(3) levels in cells plated on glycated EHS. Impaired ATP-induced Ca(2+) release could be induced by treating native EHS with laminin antibody or exposing cells to H(2)O(2) (20-200 microM). Glycated EHS impaired Ca(2+) signaling was attenuated by treatment with aminoguanidine or the antioxidant alpha-lipoic acid. The results demonstrate that matrix glycation impairs agonist-induced Ca(2+) (i) increases which may impact on regulatory functions of the endothelium and implicate possible involvement of oxidative stress.
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Affiliation(s)
- Nour B Bishara
- Microvascular Biology Group, School of Medical Sciences, RMIT University, Bundoora, Victoria, Australia
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35
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Greene V, Cao H, Schanne FAX, Bartelt DC. Oxidative stress-induced calcium signalling in Aspergillus nidulans. Cell Signal 2002; 14:437-43. [PMID: 11882388 DOI: 10.1016/s0898-6568(01)00266-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The effects of oxidative stress on levels of calcium ion (Ca(2+)) in Aspergillus nidulans were measured using strains expressing aequorin in the cytoplasm (Aeq(cyt)) and mitochondria (Aeq(mt)). When oxidative stress was induced by exposure to 10-mM H(2)O(2), the mitochondrial calcium response (Ca(mt)(2+)) was greater than the change in cytoplasmic calcium (Ca(c)(2+)). The Ca(mt)(2+) response to H(2)O(2) was dose dependent, while the increase in [Ca(c)(2+)] did not change with increasing H(2)O(2). The increase in both [Ca(c)(2+)] and [Ca(mt)(2+)] in response to oxidative stress was enhanced by exposure of cells to Ca(2+). The presence of chelator in the external medium only partially inhibited the Ca(mt)(2+) and Ca(c)(2+) responses to oxidative stress. Reagents that alter calcium fluxes had varied effects on the Ca(mt)(2+) response to peroxide. Ruthenium red blocked the increase in [Ca(mt)(2+)], while neomycin caused an even greater increase in [Ca(mt)(2+)]. Treatment with ruthenium red and neomycin had no effect on the Ca(c)(2+) response. Bafilomycin A and oligomycin had no effect on either the mitochondrial or cytoplasmic response. Inhibitors of both voltage-regulated calcium channels and intracellular calcium release channels inhibited the Ca(2+)-dependent component of the Ca(mt)(2+) response to oxidative stress. We conclude that the more significant Ca(2+) response to oxidative stress occurs in the mitochondria and that both intracellular and extracellular calcium pools can contribute to the increases in [Ca(c)(2+)] and [Ca(mt)(2+)] induced by oxidative stress.
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Affiliation(s)
- Vilma Greene
- Department of Biological Sciences, St. John's University, 8000 Utopia Parkway, Jamaica, NY 11439, USA
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36
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Jacobson J, Duchen MR. Mitochondrial oxidative stress and cell death in astrocytes —requirement for stored Ca2+ and sustained opening of the permeability transition pore. J Cell Sci 2002; 115:1175-88. [PMID: 11884517 DOI: 10.1242/jcs.115.6.1175] [Citation(s) in RCA: 195] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The role of oxidative stress is established in a range of pathologies. As mitochondria are a major source of reactive oxygen species (ROS), we have developed a model in which an intramitochondrial photosensitising agent is used to explore the consequences of mitochondrial ROS generation for mitochondrial function and cell fate in primary cells. We have found that, in astrocytes, the interplay between mitochondrial ROS and ER sequestered Ca2+ increased the frequency of transient mitochondrial depolarisations and caused mitochondrial Ca2+ loading from ER stores. The depolarisations were attributable to opening of the mitochondrial permeability transition pore (mPTP). Initially, transient events were seen in individual mitochondria, but ultimately, the mitochondrial potential(Δψm) collapsed completely and irreversibly in the whole population. Both ROS and ER Ca2+ were required to initiate these events, but neither alone was sufficient. Remarkably, the transient events alone appeared innocuous, and caused no increase in either apoptotic or necrotic cell death. By contrast, progression to complete collapse ofΔψ m caused necrotic cell death. Thus increased mitochondrial ROS generation initiates a destructive cycle involving Ca2+ release from stores and mitochondrial Ca2+-loading,which further increases ROS production. The amplification of oxidative stress and Ca2+ loading culminates in opening of the mPTP and necrotic cell death in primary brain cells.
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Affiliation(s)
- Jake Jacobson
- Department of Physiology, University College London, London, WC1E 6BT, UK
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37
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Pilitsis JG, Diaz FG, O'Regan MH, Phillis JW. Inhibition of mitochondrial Na(+)/Ca(2+) exchange by 7-chloro-5-(2-chlorophenyl)-1,5-dihydro-4,1-benzothiazepin-2(3H)-one attenuates free fatty acid efflux in rat cerebral cortex during ischemia-reperfusion injury. Neurosci Lett 2002; 321:1-4. [PMID: 11872242 DOI: 10.1016/s0304-3940(01)02377-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We evaluated the effects of 7-chloro-5-(2-chlorophenyl)-1,5-dihydro-4,1-benzothiazepin-2(3H)-one (CGP-37157) (50 muM), a specific inhibitor of mitochondrial Na(+)/Ca(2+) exchange, applied topically onto rat cerebral cortex during ischemia-reperfusion injury. Free fatty acid (FFA) levels in cortical superfusates, withdrawn at 10 min intervals from bilateral cortical windows, were analyzed by high performance liquid chromatography. During a 20 min period of ischemia in control animals, there were significant increases in all FFAs. Following reperfusion, FFA levels remained significantly elevated. Application of CGP-37157 significantly inhibited effluxes of all FFAs during both ischemia and reperfusion. These data indicate that inhibition of mitochondrial Na(+)/Ca(2+) exchange likely prevented the activation of phospholipases that usually occurs following an ischemic insult as evidenced by its attenuation of FFA efflux.
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Affiliation(s)
- Julie G Pilitsis
- Department of Neurosurgery, Wayne State University, UHC-6E, 4201 St. Antoine, Detroit, MI 48201, USA
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38
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Gerencsér AA AA, Adam-Vizi V. Selective, high-resolution fluorescence imaging of mitochondrial Ca2+ concentration. Cell Calcium 2001; 30:311-21. [PMID: 11733937 DOI: 10.1054/ceca.2001.0238] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We have developed a digital image processing technique based on highpass filtering of microfluorimetric images for selective transmission of fine image details corresponding to mitochondria. This technique enabled the detection of the mitochondrial calcium signals with high selectivity, simultaneously with the cytosolic calcium signal. The validity of this technique was supported in primary cultures of rat brain capillary endothelial cells loaded with X-rhod-1 by the results that (i) inhibition of the mitochondrial Ca2+ uptake by discharging the mitochondrial membrane potential selectively abolished the transient of the highpass filtered signal evoked by ATP, and (ii) CGP-37157, a selective blocker of the mitochondrial Na+/Ca2+ exchanger, increased the peak amplitude of highpass filtered (mitochondrial) Ca2+ transients and caused a sustained plateau. The highpass filtering technique enabled the analysis of the mitochondrial Ca2+ transients in high temporal resolution. We found a uniform and monophasic rise of [Ca2+] in the mitochondrial population of the cell, following the cytosolic [Ca2+] with a delay at onset and peak. The introduced highpass filtering technique is a powerful tool in the high spatial and temporal resolution analysis of mitochondrial calcium transients, and it could be especially important in specimens where genetically targeted probes fail.
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Affiliation(s)
- A A Gerencsér AA
- Department of Medical Biochemistry, Semmelweis University, Budapest, H-1444 P.O. Box 262, Hungary
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39
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Sedova M, Blatter LA. Intracellular sodium modulates mitochondrial calcium signaling in vascular endothelial cells. J Biol Chem 2000; 275:35402-7. [PMID: 10958797 DOI: 10.1074/jbc.m006058200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have investigated the role of extramitochondrial Na(+) for the regulation of mitochondrial Ca(2+) concentration ([Ca(2+)](m)) in permeabilized single vascular endothelial cells. [Ca(2+)](m) was measured by loading the cells with the membrane-permeant Ca(2+) indicator fluo-3/AM and subsequent removal of cytoplasmic fluo-3 by surface membrane permeabilization with digitonin. An elevation of extramitochondrial Ca(2+) resulted in a dose-dependent increase in the rate of Ca(2+) accumulation into mitochondria (k(0.5) = 3 microm) via the mitochondrial Ca(2+) uniporter. In the presence of 10 mm extramitochondrial Na(+) ([Na(+)](em)), repetitive application of brief pulses of high Ca(2+) (2-10 microm) to simulate cytoplasmic [Ca(2+)] oscillations caused transient increases of [Ca(2+)](m) characterized by a fast rising phase that was followed by a slow decay. Removal of extramitochondrial Na(+) or inhibition of mitochondrial Na(+)/Ca(2+) exchange with clonazepam blocked mitochondrial Ca(2+) efflux and resulted in a net accumulation of Ca(2+) by the mitochondria. Half-maximal activation of mitochondrial Na(+)/Ca(2+) exchange occurred at [Na(+)](em) = 4.4 mm, which is well within the physiological range of cytoplasmic [Na(+)]. This study provides evidence that Ca(2+) efflux from the mitochondria in vascular endothelial cells occurs solely via Na(+)/Ca(2+) exchange and emphasizes the important role of intracellular Na(+) for mitochondrial Ca(2+) regulation.
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Affiliation(s)
- M Sedova
- Loyola University Chicago, Stritch School of Medicine, Department of Physiology, Maywood, Illinois 60153, USA
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40
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Pocock TM, Williams B, Curry FE, Bates DO. VEGF and ATP act by different mechanisms to increase microvascular permeability and endothelial [Ca(2+)](i). Am J Physiol Heart Circ Physiol 2000; 279:H1625-34. [PMID: 11009449 DOI: 10.1152/ajpheart.2000.279.4.h1625] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vascular endothelial growth factor (VEGF) increases hydraulic conductivity (L(p)) by stimulating Ca(2+) influx into endothelial cells. To determine whether VEGF-mediated Ca(2+) influx is stimulated by release of Ca(2+) from intracellular stores, we measured the effect of Ca(2+) store depletion on VEGF-mediated increased L(p) and endothelial intracellular Ca(2+) concentration ([Ca(2+)](i)) of frog mesenteric microvessels. Inhibition of Ca(2+) influx by perfusion with NiCl(2) significantly attenuated VEGF-mediated increased [Ca(2+)](i). Depletion of Ca(2+) stores by perfusion of vessels with thapsigargin did not affect the VEGF-mediated increased [Ca(2+)](i) or the increase in L(p). In contrast, ATP-mediated increases in both [Ca(2+)](i) and L(p) were inhibited by thapsigargin perfusion, demonstrating that ATP stimulated store-mediated Ca(2+) influx. VEGF also increased Mn(2+) influx after perfusion with thapsigargin, whereas ATP did not. These data showed that VEGF increased [Ca(2+)](i) and L(p) even when Ca(2+) stores were depleted and under conditions that prevented ATP-mediated increases in [Ca(2+)](i) and L(p). This suggests that VEGF acts through a Ca(2+) store-independent mechanism, whereas ATP acts through Ca(2+) store-mediated Ca(2+) influx.
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Affiliation(s)
- T M Pocock
- Department of Physiology, University of Bristol, Bristol BS2 8EJ, LE2 7LX United Kingdom
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41
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Maechler P, Jornot L, Wollheim CB. Hydrogen peroxide alters mitochondrial activation and insulin secretion in pancreatic beta cells. J Biol Chem 1999; 274:27905-13. [PMID: 10488138 DOI: 10.1074/jbc.274.39.27905] [Citation(s) in RCA: 246] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The effects of a transient exposure to hydrogen peroxide (10 min at 200 microM H(2)O(2)) on pancreatic beta cell signal transduction and insulin secretion have been evaluated. In rat islets, insulin secretion evoked by glucose (16.7 mM) or by the mitochondrial substrate methyl succinate (5 mM) was markedly blunted following exposure to H(2)O(2). In contrast, the secretory response induced by plasma membrane depolarization (20 mM KCl) was not significantly affected. Similar results were obtained in insulinoma INS-1 cells using glucose (12.8 mM) as secretagogue. After H(2)O(2) treatment, glucose no longer depolarized the membrane potential (DeltaPsi) of INS-1 cells or increased cytosolic Ca(2+). Both DeltaPsi and Ca(2+) responses were still observed with 30 mM KCl despite an elevated baseline of cytosolic Ca(2+) appearing approximately 10 min after exposure to H(2)O(2). The mitochondrial DeltaPsi of INS-1 cells was depolarized by H(2)O(2) abolishing the hyperpolarizing action of glucose. These DeltaPsi changes correlated with altered mitochondrial morphology; the latter was not preserved by the overexpression of the antiapoptotic protein Bcl-2. Mitochondrial Ca(2+) was increased following exposure to H(2)O(2) up to the micromolar range. No further augmentation occurred after glucose addition, which normally raises this parameter. Nevertheless, KCl was still efficient in enhancing mitochondrial Ca(2+). Cytosolic ATP was markedly reduced by H(2)O(2) treatment, probably explaining the decreased endoplasmic reticulum Ca(2+). Taken together, these data point to the mitochondria as primary targets for H(2)O(2) damage, which will eventually interrupt the transduction of signals normally coupling glucose metabolism to insulin secretion.
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Affiliation(s)
- P Maechler
- Division of Clinical Biochemistry, Department of Internal Medicine, University Medical Center, CH-1211 Geneva, Switzerland
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