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Aktay I, Billur D, Tuncay E, Turan B. An Overexpression of SLC30A6 Gene Contributes to Cardiomyocyte Dysfunction via Affecting Mitochondria and Inducing Activations in K-Acetylation and Epigenetic Proteins. Biochem Genet 2024; 62:3198-3214. [PMID: 38091184 DOI: 10.1007/s10528-023-10602-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 11/13/2023] [Indexed: 07/31/2024]
Abstract
Intracellular free Zn2+ ([Zn2+]i) is less than 1-nM in cardiomyocytes and its regulation is performed with Zn2+-transporters. However, the roles of Zn2+-transporters in cardiomyocytes are not defined exactly yet. Here, we aimed to examine the role of an overexpression and subcellular localization of a ZnT6 in insulin-resistance mimic H9c2 cardiomyoblasts (IR-cells; 50-μM palmitic acid for 24-h incubation). We used both IR-cells and ZnT6-overexpressed (ZnT6OE) cells in comparison to those of H9c2 cells (CON-cells). The IR-cells have higher ZnT6-protein levels than CON-cells while this level was similar to those of ZnT6OE-cells. The [Zn2+]i in IR-cells was increased significantly and mitochondrial localization of ZnT6 was demonstrated in these cells by using confocal microscopy visualization. Furthermore, electron microscopy analysis demonstrated abnormal morphological appearance in both IR-cells and ZnT6OE-cells characterized by irregular mitochondrion cristae and condensed and dilated cisterna in the sarcoplasmic reticulum. Mitochondria were similarly depolarized in both IR-cells and ZnT6OE-cells. The protein expression level of a mitofusin protein MFN2 in the IR-cells was decreased, significantly, whereas, it was found significantly upregulated in both ZnT6-OE-cells and IR-incubated ZnT6OE-cells, which demonstrates the role of ZnT6-overexpression but not IR. Additionally, the total protein level of a mitochondrial fission protein, dynamin-related protein 1, DRP1 was found to be increased over 1.5-fold in IR-cells while this increase was found to be higher in the ZnT6OE-cells than those of IR-cells, demonstrating an additional effect on IR-increase. ZnT6-overexpression induced also significant increases in K-acetylation, trimethylation of histone H3 lysine27, and mono-methylation of histone H3 lysine36, in a similar manner to those of IR-cells. Overall, our data point out an important contribution of ZnT6-overexpression to IR-induced cellular changes, such as alteration in mitochondria function and activation of epigenetic modifications.
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Affiliation(s)
- Irem Aktay
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Deniz Billur
- Department of Histology & Embryology, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Erkan Tuncay
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Belma Turan
- Department of Biophysics, Faculty of Medicine, Lokman Hekim University, Ankara, Turkey.
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Yang F, Smith MJ, Siow RCM, Aarsland D, Maret W, Mann GE. Interactions between zinc and NRF2 in vascular redox signalling. Biochem Soc Trans 2024; 52:269-278. [PMID: 38372426 PMCID: PMC10903478 DOI: 10.1042/bst20230490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 02/20/2024]
Abstract
Recent evidence highlights the importance of trace metal micronutrients such as zinc (Zn) in coronary and vascular diseases. Zn2+ plays a signalling role in modulating endothelial nitric oxide synthase and protects the endothelium against oxidative stress by up-regulation of glutathione synthesis. Excessive accumulation of Zn2+ in endothelial cells leads to apoptotic cell death resulting from dysregulation of glutathione and mitochondrial ATP synthesis, whereas zinc deficiency induces an inflammatory phenotype, associated with increased monocyte adhesion. Nuclear factor-E2-related factor 2 (NRF2) is a transcription factor known to target hundreds of different genes. Activation of NRF2 affects redox metabolism, autophagy, cell proliferation, remodelling of the extracellular matrix and wound healing. As a redox-inert metal ion, Zn has emerged as a biomarker in diagnosis and as a therapeutic approach for oxidative-related diseases due to its close link to NRF2 signalling. In non-vascular cell types, Zn has been shown to modify conformations of the NRF2 negative regulators Kelch-like ECH-associated Protein 1 (KEAP1) and glycogen synthase kinase 3β (GSK3β) and to promote degradation of BACH1, a transcriptional suppressor of select NRF2 genes. Zn can affect phosphorylation signalling, including mitogen-activated protein kinases (MAPK), phosphoinositide 3-kinases and protein kinase C, which facilitate NRF2 phosphorylation and nuclear translocation. Notably, several NRF2-targeted proteins have been suggested to modify cellular Zn concentration via Zn exporters (ZnTs) and importers (ZIPs) and the Zn buffering protein metallothionein. This review summarises the cross-talk between reactive oxygen species, Zn and NRF2 in antioxidant responses of vascular cells against oxidative stress and hypoxia/reoxygenation.
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Affiliation(s)
- Fan Yang
- School of Cardiovascular and Metabolic Medicine and Sciences, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, 150 Stamford Street, London SE1 9NH, U.K
| | - Matthew J Smith
- School of Cardiovascular and Metabolic Medicine and Sciences, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, 150 Stamford Street, London SE1 9NH, U.K
| | - Richard C M Siow
- School of Cardiovascular and Metabolic Medicine and Sciences, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, 150 Stamford Street, London SE1 9NH, U.K
| | - Dag Aarsland
- Department of Old Age Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College, London, U.K
- Centre for Age-Related Medicine, Stavanger University Hospital, Stavanger, Norway
| | - Wolfgang Maret
- Departments of Biochemistry and Nutritional Sciences, School of Life Course and Population Sciences, Faculty of Life Sciences and Medicine, King's College, London, U.K
| | - Giovanni E Mann
- School of Cardiovascular and Metabolic Medicine and Sciences, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, 150 Stamford Street, London SE1 9NH, U.K
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Dorward AM, Stewart AJ, Pitt SJ. The role of Zn2+ in shaping intracellular Ca2+ dynamics in the heart. J Gen Physiol 2023; 155:e202213206. [PMID: 37326614 PMCID: PMC10276528 DOI: 10.1085/jgp.202213206] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 04/18/2023] [Accepted: 05/22/2023] [Indexed: 06/17/2023] Open
Abstract
Increasing evidence suggests that Zn2+ acts as a second messenger capable of transducing extracellular stimuli into intracellular signaling events. The importance of Zn2+ as a signaling molecule in cardiovascular functioning is gaining traction. In the heart, Zn2+ plays important roles in excitation-contraction (EC) coupling, excitation-transcription coupling, and cardiac ventricular morphogenesis. Zn2+ homeostasis in cardiac tissue is tightly regulated through the action of a combination of transporters, buffers, and sensors. Zn2+ mishandling is a common feature of various cardiovascular diseases. However, the precise mechanisms controlling the intracellular distribution of Zn2+ and its variations during normal cardiac function and during pathological conditions are not fully understood. In this review, we consider the major pathways by which the concentration of intracellular Zn2+ is regulated in the heart, the role of Zn2+ in EC coupling, and discuss how Zn2+ dyshomeostasis resulting from altered expression levels and efficacy of Zn2+ regulatory proteins are key drivers in the progression of cardiac dysfunction.
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Affiliation(s)
- Amy M. Dorward
- School of Medicine, University of St Andrews, St Andrews, UK
| | - Alan J. Stewart
- School of Medicine, University of St Andrews, St Andrews, UK
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Gaburjakova J, Gaburjakova M. The Cardiac Ryanodine Receptor Provides a Suitable Pathway for the Rapid Transport of Zinc (Zn2+). Cells 2022; 11:cells11050868. [PMID: 35269490 PMCID: PMC8909583 DOI: 10.3390/cells11050868] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 02/25/2022] [Accepted: 03/01/2022] [Indexed: 12/13/2022] Open
Abstract
The sarcoplasmic reticulum (SR) in cardiac muscle is suggested to act as a dynamic storage for Zn2+ release and reuptake, albeit it is primarily implicated in the Ca2+ signaling required for the cardiac cycle. A large Ca2+ release from the SR is mediated by the cardiac ryanodine receptor (RYR2), and while this has a prominent conductance for Ca2+ in vivo, it also conducts other divalent cations in vitro. Since Zn2+ and permeant Mg2+ have similar physical properties, we tested if the RYR2 channel also conducts Zn2+. Using the method of planar lipid membranes, we evidenced that the RYR2 channel is permeable to Zn2+ with a considerable conductance of 81.1 ± 2.4 pS, which was significantly lower than the values for Ca2+ (127.5 ± 1.8 pS) and Mg2+ (95.3 ± 1.4 pS), obtained under the same asymmetric conditions. Despite similar physical properties, the intrinsic Zn2+ permeability (PCa/PZn = 2.65 ± 0.19) was found to be ~2.3-fold lower than that of Mg2+ (PCa/PMg = 1.146 ± 0.071). Further, we assessed whether the channel itself could be a direct target of the Zn2+ current, having the Zn2+ finger extended into the cytosolic vestibular portion of the permeation pathway. We attempted to displace Zn2+ from the RYR2 Zn2+ finger to induce its structural defects, which are associated with RYR2 dysfunction. Zn2+ chelators were added to the channel cytosolic side or strongly competing cadmium cations (Cd2+) were allowed to permeate the RYR2 channel. Only the Cd2+ current was able to cause the decay of channel activity, presumably as a result of Zn2+ to Cd2+ replacement. Our findings suggest that the RYR2 channel can provide a suitable pathway for rapid Zn2+ escape from the cardiac SR; thus, the channel may play a role in local and/or global Zn2+ signaling in cardiomyocytes.
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Abstract
Zn2+ ions are essential in many physiological processes, including enzyme catalysis, protein structural stabilization, and the regulation of many proteins. The affinities of proteins for Zn2+ ions span several orders of magnitude, with catalytic Zn2+ ions generally held more tightly than structural or regulatory ones. Metal carrier proteins, most of which are not specific for Zn2+, bind these ions with a broad range of affinities that overlap those of catalytic, structural, and regulatory Zn2+ ions and are thought to be responsible for distributing the metal through most cells, tissues, and fluid compartments. While little is known about how many proteins obtain or release these ions, there is now considerable experimental evidence suggesting that metal carrier proteins may be responsible for transferring metals to and from some Zn2+-dependent proteins, thus serving as a major regulatory factor for them. In this review, the biological roles of Zn2+ and structures of Zn2+ binding sites are examined, and experimental evidence demonstrating the direct participation of metal carrier proteins in enzyme regulation is discussed. Mechanisms of metal ion transfer are also offered, and the potential physiological significance of this phenomenon is explored.
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Li L, Niu P, Wang X, Bing F, Tan W, Huo Y. Short-Term Inhalation of Ultrafine Zinc Particles Could Alleviate Cardiac Dysfunctions in Rats of Myocardial Infarction. Front Bioeng Biotechnol 2021; 9:646533. [PMID: 33937215 PMCID: PMC8081065 DOI: 10.3389/fbioe.2021.646533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Accepted: 03/25/2021] [Indexed: 12/27/2022] Open
Abstract
It is not clear for inhalation of ultrafine metal particles in air pollution to impair human health. In the study, we aimed to investigate whether short-term (4 weeks) inhalation of ultrafine zinc particles could deteriorate the cardiac and hemodynamic functions in rats of myocardial infarction (MI). MI was induced in Wistar rats through coronary artery ligation surgery and given an inhalation of ultrafine zinc particles for 4 weeks (post-MI 4 weeks, 4 days per week, and 4 h per day). Cardiac strain and strain rate were quantified by the speckle tracking echocardiography. The pressure and flow wave were recorded in the carotid artery and analyzed by using the Womersley model. Myocardial infarction resulted in the LV wall thinning, LV cavity dilation, remarkable decrease of ejection fraction, dp/dt Max, −dp/dt Min, myocardial strain and strain rates, and increased LV end-diastolic pressure, as well as impaired hemodynamic environment. The short-term inhalation of ultrafine zinc particles significantly alleviated cardiac and hemodynamic dysfunctions, which could protect from the MI-induced myocardial and hemodynamic impairments albeit it is unknown for the long-term inhalation.
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Affiliation(s)
- Li Li
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Pei Niu
- PKU-HKUST Shenzhen-Hong Kong Institution, Shenzhen, China
| | - Xuan Wang
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Fangbo Bing
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Wenchang Tan
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China.,PKU-HKUST Shenzhen-Hong Kong Institution, Shenzhen, China.,Peking University Shenzhen Graduate School, Shenzhen, China.,Shenzhen Bay Laboratory, Shenzhen, China
| | - Yunlong Huo
- Institute of Mechanobiology and Medical Engineering, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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Wedler N, Matthäus T, Strauch B, Dilger E, Waterstraat M, Mangerich A, Hartwig A. Impact of the Cellular Zinc Status on PARP-1 Activity and Genomic Stability in HeLa S3 Cells. Chem Res Toxicol 2021; 34:839-848. [PMID: 33645215 DOI: 10.1021/acs.chemrestox.0c00452] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Poly(ADP-ribose) polymerase 1 (PARP-1) is actively involved in several DNA repair pathways, especially in the detection of DNA lesions and DNA damage signaling. However, the mechanisms of PARP-1 activation are not fully understood. PARP-1 contains three zinc finger structures, among which the first zinc finger has a remarkably low affinity toward zinc ions. Within the present study, we investigated the impact of the cellular zinc status on PARP-1 activity and on genomic stability in HeLa S3 cells. Significant impairment of H2O2-induced poly(ADP-ribosyl)ation and an increase in DNA strand breaks were detected in the case of zinc depletion by the zinc chelator N,N,N',N'-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (TPEN) which reduced the total and labile zinc concentrations. On the contrary, preincubation of cells with ZnCl2 led to an overload of total as well as labile zinc and resulted in an increased poly(ADP-ribosyl)ation response upon H2O2 treatment. Furthermore, the impact of the cellular zinc status on gene expression profiles was investigated via high-throughput RT-qPCR, analyzing 95 genes related to metal homeostasis, DNA damage and oxidative stress response, cell cycle regulation and proliferation. Genes encoding metallothioneins responded most sensitively on conditions of mild zinc depletion or moderate zinc overload. Zinc depletion induced by higher concentrations of TPEN led to a significant induction of genes encoding DNA repair factors and cell cycle arrest, indicating the induction of DNA damage and genomic instability. Zinc overload provoked an up-regulation of the oxidative stress response. Altogether, the results highlight the potential role of zinc signaling for PARP-1 activation and the maintenance of genomic stability.
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Affiliation(s)
- Nadin Wedler
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Tizia Matthäus
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Bettina Strauch
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Elena Dilger
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Martin Waterstraat
- Department of Food Chemistry and Phytochemistry, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Aswin Mangerich
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany
| | - Andrea Hartwig
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131 Karlsruhe, Germany
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Zinc Preconditioning Provides Cytoprotection following Iodinated Contrast Media Exposure in In Vitro Models. CONTRAST MEDIA & MOLECULAR IMAGING 2021; 2021:6686803. [PMID: 33679268 PMCID: PMC7904368 DOI: 10.1155/2021/6686803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 01/26/2021] [Accepted: 02/08/2021] [Indexed: 11/17/2022]
Abstract
Methods Normal human proximal renal kidney cells (HK-2) were preconditioned with either increasing doses of ZnCl2 or control. Following this preconditioning, cells were exposed to increasing concentrations of Iohexol 300 mg I2/ml for four hours. Key outcome measures included cell survival (MTT colorimetric assay) and ROS generation (H2DCFDA fluorescence assay). Results Contrast media induced a dose-dependent reduction in survival of HK-2 cells. Compared to control, contrast media at 150, 225, and 300 mg I2/ml resulted in 69.5% (SD 8.8%), 37.3% (SD 4.8%), and 4.8% (SD 6.6%) cell survival, respectively (p < 0.001). Preconditioning with 37.5 μM and 50 μM ZnCl2 increased cell survival by 173% (SD 27.8%) (p < 0.001) and 219% (SD 32.2%) (p < 0.001), respectively, compared to control preconditioning. Zinc preconditioning resulted in a reduction of ROS generation. Zinc pre-conditioning with 37.5 μM μM ZnCl2 reduced ROS generation by 46% (p < 0.001) compared to control pre-conditioning. Conclusions Zinc preconditioning reduces oxidative stress following exposure to radiographic contrast media which in turn results in increased survival of renal cells. Translation of this in vitro finding in animal models will lay the foundation for future use of zinc preconditioning against contrast induced nephropathy.
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The role of labile Zn 2+ and Zn 2+-transporters in the pathophysiology of mitochondria dysfunction in cardiomyocytes. Mol Cell Biochem 2020; 476:971-989. [PMID: 33225416 DOI: 10.1007/s11010-020-03964-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 10/23/2020] [Indexed: 02/06/2023]
Abstract
An important energy supplier of cardiomyocytes is mitochondria, similar to other mammalian cells. Studies have demonstrated that any defect in the normal processes controlled by mitochondria can lead to abnormal ROS production, thereby high oxidative stress as well as lack of ATP. Taken into consideration, the relationship between mitochondrial dysfunction and overproduction of ROS as well as the relation between increased ROS and high-level release of intracellular labile Zn2+, those bring into consideration the importance of the events related with those stimuli in cardiomyocytes responsible from cellular Zn2+-homeostasis and responsible Zn2+-transporters associated with the Zn2+-homeostasis and Zn2+-signaling. Zn2+-signaling, controlled by cellular Zn2+-homeostatic mechanisms, is regulated with intracellular labile Zn2+ levels, which are controlled, especially, with the two Zn2+-transporter families; ZIPs and ZnTs. Our experimental studies in mammalian cardiomyocytes and human heart tissue showed that Zn2+-transporters localizes to mitochondria besides sarco(endo)plasmic reticulum and Golgi under physiological condition. The protein levels as well as functions of those transporters can re-distribute under pathological conditions, therefore, they can interplay among organelles in cardiomyocytes to adjust a proper intracellular labile Zn2+ level. In the present review, we aimed to summarize the already known Zn2+-transporters localize to mitochondria and function to stabilize not only the cellular Zn2+ level but also cellular oxidative stress status. In conclusion, one can propose that a detailed understanding of cellular Zn2+-homeostasis and Zn2+-signaling through mitochondria may emphasize the importance of new mitochondria-targeting agents for prevention and/or therapy of cardiovascular dysfunction in humans.
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Thokala S, Bodiga VL, Kudle MR, Bodiga S. Comparative Response of Cardiomyocyte ZIPs and ZnTs to Extracellular Zinc and TPEN. Biol Trace Elem Res 2019; 192:297-307. [PMID: 30778755 DOI: 10.1007/s12011-019-01671-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 02/07/2019] [Indexed: 12/19/2022]
Abstract
Intracellular zinc concentrations are tightly regulated by the coordinated regulation of ZIPs and ZnTs. Very little is known about the regulation of these transporters in cardiomyocytes, in response to extracellular zinc. Adult rat cardiomyocytes express ZnTs 1, 2, 5, and 9, in addition to ZIPs 1, 2, 3, 6, 7, 9, 10, 11, 13, and 14. We have determined the intracellular free zinc levels using Zinpyr-1 fluorescence and studied response of ZIP and ZnT mRNA by real-time PCR to the changes in extracellular zinc and TPEN in adult rat ventricular myocytes. TPEN downregulated ZnT1, ZnT2, and ZIP11 mRNAs but upregulated ZnT5, ZIP2, ZIP7, ZIP10, ZIP13, and ZIP14 mRNAs. Zinc supplementation upregulated ZnT1, ZnT2 mRNA but downregulated ZnT5, ZIP1, ZIP2, ZIP3, ZIP7, ZIP9, and ZIP10 mRNA. The negative regulation of ZIPs by zinc excess can be explained in terms of zinc homeostasis as these transporters may act to protect cells from zinc over accumulation by reducing zinc influx when the extracellular concentration of zinc is high. Similarly, the ZnT expression appears to be regulated to avoid loss of zinc from the intracellular milieu, under zinc-deficient conditions.
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Affiliation(s)
- Sandhya Thokala
- Department of Biochemistry, Kakatiya University, Vidyaranyapuri, Warangal Urban, Telangana, India
| | - Vijaya Lakshmi Bodiga
- Department of Biochemistry and Molecular Biology, Institute of Genetics and Hospital for Genetic Diseases, Osmania University, Begumpet, Hyderabad, Telangana, India
| | - Madhukar Rao Kudle
- Department of Biochemistry, Kakatiya University, Vidyaranyapuri, Warangal Urban, Telangana, India
| | - Sreedhar Bodiga
- Department of Biochemistry, Kakatiya University, Vidyaranyapuri, Warangal Urban, Telangana, India.
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Mitochondria-Targeting Antioxidant Provides Cardioprotection through Regulation of Cytosolic and Mitochondrial Zn 2+ Levels with Re-Distribution of Zn 2+-Transporters in Aged Rat Cardiomyocytes. Int J Mol Sci 2019; 20:ijms20153783. [PMID: 31382470 PMCID: PMC6695787 DOI: 10.3390/ijms20153783] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/12/2019] [Accepted: 06/17/2019] [Indexed: 12/29/2022] Open
Abstract
Aging is an important risk factor for cardiac dysfunction. Heart during aging exhibits a depressed mechanical activity, at least, through mitochondria-originated increases in ROS. Previously, we also have shown a close relationship between increased ROS and cellular intracellular free Zn2+ ([Zn2+]i) in cardiomyocytes under pathological conditions as well as the contribution of some re-expressed levels of Zn2+-transporters for redistribution of [Zn2+]i among suborganelles. Therefore, we first examined the cellular (total) [Zn2+] and then determined the protein expression levels of Zn2+-transporters in freshly isolated ventricular cardiomyocytes from 24-month rat heart compared to those of 6-month rats. The [Zn2+]i in the aged-cardiomyocytes was increased, at most, due to increased ZIP7 and ZnT8 with decreased levels of ZIP8 and ZnT7. To examine redistribution of the cellular [Zn2+]i among suborganelles, such as Sarco/endoplasmic reticulum, S(E)R, and mitochondria ([Zn2+]SER and [Zn2+]Mit), a cell model (with galactose) to mimic the aged-cell in rat ventricular cell line H9c2 was used and demonstrated that there were significant increases in [Zn2+]Mit with decreases in [Zn2+]SER. In addition, the re-distribution of these Zn2+-transporters were markedly changed in mitochondria (increases in ZnT7 and ZnT8 with no changes in ZIP7 and ZIP8) and S(E)R (increase in ZIP7 and decrease in ZnT7 with no changes in both ZIP8 and ZnT8) both of them isolated from freshly isolated ventricular cardiomyocytes from aged-rats. Furthermore, we demonstrated that cellular levels of ROS, both total and mitochondrial lysine acetylation (K-Acetylation), and protein-thiol oxidation were significantly high in aged-cardiomyocytes from 24-month old rats. Using a mitochondrial-targeting antioxidant, MitoTEMPO (1 µM, 5-h incubation), we provided an important data associated with the role of mitochondrial-ROS production in the [Zn2+]i-dyshomeostasis of the ventricular cardiomyocytes from 24-month old rats. Overall, our present data, for the first time, demonstrated that a direct mitochondria-targeting antioxidant treatment can be a new therapeutic strategy during aging in the heart through a well-controlled [Zn2+] distribution among cytosol and suborganelles with altered expression levels of the Zn2+-transporters.
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Olgar Y, Durak A, Tuncay E, Bitirim CV, Ozcinar E, Inan MB, Tokcaer-Keskin Z, Akcali KC, Akar AR, Turan B. Increased free Zn 2+ correlates induction of sarco(endo)plasmic reticulum stress via altered expression levels of Zn 2+ -transporters in heart failure. J Cell Mol Med 2018; 22:1944-1956. [PMID: 29333637 PMCID: PMC5824399 DOI: 10.1111/jcmm.13480] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 10/29/2017] [Indexed: 12/14/2022] Open
Abstract
Zn2+ -homoeostasis including free Zn2+ ([Zn2+ ]i ) is regulated through Zn2+ -transporters and their comprehensive understanding may be important due to their contributions to cardiac dysfunction. Herein, we aimed to examine a possible role of Zn2+ -transporters in the development of heart failure (HF) via induction of ER stress. We first showed localizations of ZIP8, ZIP14 and ZnT8 to both sarcolemma and S(E)R in ventricular cardiomyocytes (H9c2 cells) using confocal together with calculated Pearson's coefficients. The expressions of ZIP14 and ZnT8 were significantly increased with decreased ZIP8 level in HF. Moreover, [Zn2+ ]i was significantly high in doxorubicin-treated H9c2 cells compared to their controls. We found elevated levels of ER stress markers, GRP78 and CHOP/Gadd153, confirming the existence of ER stress. Furthermore, we measured markedly increased total PKC and PKCα expression and PKCα-phosphorylation in HF. A PKC inhibition induced significant decrease in expressions of these ER stress markers compared to controls. Interestingly, direct increase in [Zn2+ ]i using zinc-ionophore induced significant increase in these markers. On the other hand, when we induced ER stress directly with tunicamycin, we could not observe any effect on expression levels of these Zn2+ transporters. Additionally, increased [Zn2+ ]i could induce marked activation of PKCα. Moreover, we observed marked decrease in [Zn2+ ]i under PKC inhibition in H9c2 cells. Overall, our present data suggest possible role of Zn2+ transporters on an intersection pathway with increased [Zn2+ ]i and PKCα activation and induction of HF, most probably via development of ER stress. Therefore, our present data provide novel information how a well-controlled [Zn2+ ]i via Zn2+ transporters and PKCα can be important therapeutic approach in prevention/treatment of HF.
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Affiliation(s)
- Yusuf Olgar
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Aysegul Durak
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Erkan Tuncay
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
| | | | - Evren Ozcinar
- Department of Cardiovascular Surgery, Heart Center, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Mustafa Bahadir Inan
- Department of Cardiovascular Surgery, Heart Center, Ankara University Faculty of Medicine, Ankara, Turkey
| | | | - Kamil Can Akcali
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Ahmet Ruchan Akar
- Department of Cardiovascular Surgery, Heart Center, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Belma Turan
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
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Turan B, Tuncay E. Impact of Labile Zinc on Heart Function: From Physiology to Pathophysiology. Int J Mol Sci 2017; 18:ijms18112395. [PMID: 29137144 PMCID: PMC5713363 DOI: 10.3390/ijms18112395] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 11/02/2017] [Accepted: 11/08/2017] [Indexed: 12/15/2022] Open
Abstract
Zinc plays an important role in biological systems as bound and histochemically reactive labile Zn2+. Although Zn2+ concentration is in the nM range in cardiomyocytes at rest and increases dramatically under stimulation, very little is known about precise mechanisms controlling the intracellular distribution of Zn2+ and its variations during cardiac function. Recent studies are focused on molecular and cellular aspects of labile Zn2+ and its homeostasis in mammalian cells and growing evidence clarified the molecular mechanisms underlying Zn2+-diverse functions in the heart, leading to the discovery of novel physiological functions of labile Zn2+ in parallel to the discovery of subcellular localization of Zn2+-transporters in cardiomyocytes. Additionally, important experimental data suggest a central role of intracellular labile Zn2+ in excitation-contraction coupling in cardiomyocytes by shaping Ca2+ dynamics. Cellular labile Zn2+ is tightly regulated against its adverse effects through either Zn2+-transporters, Zn2+-binding molecules or Zn2+-sensors, and, therefore plays a critical role in cellular signaling pathways. The present review summarizes the current understanding of the physiological role of cellular labile Zn2+ distribution in cardiomyocytes and how a remodeling of cellular Zn2+-homeostasis can be important in proper cell function with Zn2+-transporters under hyperglycemia. We also emphasize the recent investigations on Zn2+-transporter functions from the standpoint of human heart health to diseases together with their clinical interest as target proteins in the heart under pathological condition, such as diabetes.
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Affiliation(s)
- Belma Turan
- Department of Biophysics, Ankara University, Faculty of Medicine, 06100 Ankara, Turkey.
| | - Erkan Tuncay
- Department of Biophysics, Ankara University, Faculty of Medicine, 06100 Ankara, Turkey.
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14
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Induction of endoplasmic reticulum stress and changes in expression levels of Zn 2+-transporters in hypertrophic rat heart. Mol Cell Biochem 2017; 440:209-219. [PMID: 28849306 DOI: 10.1007/s11010-017-3168-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 08/16/2017] [Indexed: 12/15/2022]
Abstract
Clinical and experimental studies have shown an association between intracellular free Zn2+ ([Zn2+]i)-dyshomeostasis and cardiac dysfunction besides [Ca2+]i-dyshomeostasis. Since [Zn2+]i-homeostasis is regulated through Zn2+-transporters depending on their subcellular distributions, one can hypothesize that any imbalance in Zn2+-homeostasis via alteration in Zn2+-transporters may be associated with the induction of ER stress and apoptosis in hypertrophic heart. We used a transverse aortic constriction (TAC) model to induce hypertrophy in young male rat heart. We confirmed the development of hypertrophy with a high ratio of heart to body weight and cardiomyocyte capacitance. The expression levels of ER stress markers GRP78, CHOP/Gadd153, and calnexin are significantly high in TAC-group in comparison to those of controls (SHAM-group). Additionally, we detected high expression levels of apoptotic status marker proteins such as the serine kinase GSK-3β, Bax-to-Bcl-2 ratio, and PUMA in TAC-group in comparison to SHAM-group. The ratios of phospho-Akt to Akt and phospho-NFκB to the NFκB are significantly higher in TAC-group than in SHAM-group. Furthermore, we observed markedly increased phospho-PKCα and PKCα levels in TAC-group. We, also for the first time, determined significantly increased ZIP7, ZIP14, and ZnT8 expressions along with decreased ZIP8 and ZnT7 levels in the heart tissue from TAC-group in comparison to SHAM-group. Furthermore, a roughly calculated total expression level of ZIPs responsible for Zn2+-influx into the cytosol (increased about twofold) can be also responsible for the markedly increased [Zn2+]i detected in hypertrophic cardiomyocytes. Taking into consideration the role of increased [Zn2+]i via decreased ER-[Zn2+] in the induction of ER stress in cardiomyocytes, our present data suggest that differential changes in the expression levels of Zn2+-transporters can underlie mechanical dysfunction, in part due to the induction of ER stress and apoptosis in hypertrophic heart via increased [Zn2+]i- besides [Ca2+]i-dyshomeostasis.
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15
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Lee SR, Noh SJ, Pronto JR, Jeong YJ, Kim HK, Song IS, Xu Z, Kwon HY, Kang SC, Sohn EH, Ko KS, Rhee BD, Kim N, Han J. The Critical Roles of Zinc: Beyond Impact on Myocardial Signaling. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2015; 19:389-99. [PMID: 26330751 PMCID: PMC4553398 DOI: 10.4196/kjpp.2015.19.5.389] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 06/04/2015] [Accepted: 06/08/2015] [Indexed: 12/15/2022]
Abstract
Zinc has been considered as a vital constituent of proteins, including enzymes. Mobile reactive zinc (Zn(2+)) is the key form of zinc involved in signal transductions, which are mainly driven by its binding to proteins or the release of zinc from proteins, possibly via a redox switch. There has been growing evidence of zinc's critical role in cell signaling, due to its flexible coordination geometry and rapid shifts in protein conformation to perform biological reactions. The importance and complexity of Zn(2+) activity has been presumed to parallel the degree of calcium's participation in cellular processes. Whole body and cellular Zn(2+) levels are largely regulated by metallothioneins (MTs), Zn(2+) importers (ZIPs), and Zn(2+) transporters (ZnTs). Numerous proteins involved in signaling pathways, mitochondrial metabolism, and ion channels that play a pivotal role in controlling cardiac contractility are common targets of Zn(2+). However, these regulatory actions of Zn(2+) are not limited to the function of the heart, but also extend to numerous other organ systems, such as the central nervous system, immune system, cardiovascular tissue, and secretory glands, such as the pancreas, prostate, and mammary glands. In this review, the regulation of cellular Zn(2+) levels, Zn(2+)-mediated signal transduction, impacts of Zn(2+) on ion channels and mitochondrial metabolism, and finally, the implications of Zn(2+) in health and disease development were outlined to help widen the current understanding of the versatile and complex roles of Zn(2+).
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Affiliation(s)
- Sung Ryul Lee
- Department of Integrated Biomedical Science, Cardiovascular and Metabolic disease Center, College of Medicine, Inje University, Busan 614-735, Korea
| | - Su Jin Noh
- Department of Physiology, Graduate School of Inje University, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
| | - Julius Ryan Pronto
- Department of Physiology, Graduate School of Inje University, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
| | - Yu Jeong Jeong
- Department of Physiology, Graduate School of Inje University, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
| | - Hyoung Kyu Kim
- Department of Integrated Biomedical Science, Cardiovascular and Metabolic disease Center, College of Medicine, Inje University, Busan 614-735, Korea
| | - In Sung Song
- College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
| | - Zhelong Xu
- Department of Physiology and Pathophysiology, Tianjin Medical University, Tainjin 300070, P.R. China
| | - Hyog Young Kwon
- Soonchunhyang Institute of Medio-bio Science (SIMS), Soonchunhyang University, Cheonan 336-745, Korea
| | - Se Chan Kang
- Department of Life Science, Gachon University, Seongnam 461-701, Korea
| | - Eun-Hwa Sohn
- Department of Herbal Medicine Resource, Kangwon National University, Samcheok 245-711, Korea
| | - Kyung Soo Ko
- College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
| | - Byoung Doo Rhee
- College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
| | - Nari Kim
- College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
| | - Jin Han
- College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea
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16
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Woodier J, Rainbow RD, Stewart AJ, Pitt SJ. Intracellular Zinc Modulates Cardiac Ryanodine Receptor-mediated Calcium Release. J Biol Chem 2015; 290:17599-610. [PMID: 26041778 PMCID: PMC4498093 DOI: 10.1074/jbc.m115.661280] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Indexed: 01/03/2023] Open
Abstract
Aberrant Zn2+ homeostasis is a hallmark of certain cardiomyopathies associated with altered contractile force. In this study, we addressed whether Zn2+ modulates cardiac ryanodine receptor gating and Ca2+ dynamics in isolated cardiomyocytes. We reveal that Zn2+ is a high affinity regulator of RyR2 displaying three modes of operation. Picomolar free Zn2+ concentrations potentiate RyR2 responses, but channel activation is still dependent on the presence of cytosolic Ca2+. At concentrations of free Zn2+ >1 nm, Zn2+ is the main activating ligand, and the dependence on Ca2+ is removed. Zn2+ is therefore a higher affinity activator of RyR2 than Ca2+. Millimolar levels of free Zn2+ were found to inhibit channel openings. In cardiomyocytes, consistent with our single channel results, we show that Zn2+ modulates both the frequency and amplitude of Ca2+ waves in a concentration-dependent manner and that physiological levels of Zn2+ elicit Ca2+ release in the absence of activating levels of cytosolic Ca2+. This highlights a new role for intracellular Zn2+ in shaping Ca2+ dynamics in cardiomyocytes through modulation of RyR2 gating.
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Affiliation(s)
- Jason Woodier
- From the School of Medicine, University of St. Andrews, St. Andrews KY16 9TF, United Kingdom and
| | - Richard D Rainbow
- the Department of Cardiovascular Sciences, University of Leicester, Clinical Sciences Wing, Glenfield General Hospital, Leicester LE3 9QP, United Kingdom
| | - Alan J Stewart
- From the School of Medicine, University of St. Andrews, St. Andrews KY16 9TF, United Kingdom and
| | - Samantha J Pitt
- From the School of Medicine, University of St. Andrews, St. Andrews KY16 9TF, United Kingdom and
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17
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Enhancement of cellular antioxidant-defence preserves diastolic dysfunction via regulation of both diastolic Zn2+ and Ca2+ and prevention of RyR2-leak in hyperglycemic cardiomyocytes. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:290381. [PMID: 24693334 PMCID: PMC3945998 DOI: 10.1155/2014/290381] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 12/17/2013] [Indexed: 01/03/2023]
Abstract
We examined whether cellular antioxidant-defence enhancement preserves diastolic dysfunction via regulation of both diastolic intracellular free Zn2+ and Ca2+ levels ([Zn2+]i and [Ca2+]i) levels N-acetyl cysteine (NAC) treatment (4 weeks) of diabetic rats preserved altered cellular redox state and also prevented diabetes-induced tissue damage and diastolic dysfunction with marked normalizations in the resting [Zn2+]i and [Ca2+]i. The kinetic parameters of transient changes in Zn2+ and Ca2+ under electrical stimulation and the spatiotemporal properties of Zn2+ and Ca2+ sparks in resting cells are found to be normal in the treated diabetic group. Biochemical analysis demonstrated that the NAC treatment also antagonized hyperphosphorylation of cardiac ryanodine receptors (RyR2) and significantly restored depleted protein levels of both RyR2 and calstabin2. Incubation of cardiomyocytes with 10 µM ZnCl2 exerted hyperphosphorylation in RyR2 as well as higher phosphorphorylations in both PKA and CaMKII in a concentration-dependent manner, similar to hyperglycemia. Our present data also showed that a subcellular oxidative stress marker, NF-κB, can be activated if the cells are exposed directly to Zn2+. We thus for the first time report that an enhancement of antioxidant defence in diabetics via directly targeting heart seems to prevent diastolic dysfunction due to modulation of RyR2 macromolecular-complex thereby leading to normalized [Ca2+]i and [Zn2+]i
in cardiomyocytes.
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18
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Qin Y, Miranda JG, Stoddard CI, Dean KM, Galati DF, Palmer AE. Direct comparison of a genetically encoded sensor and small molecule indicator: implications for quantification of cytosolic Zn(2+). ACS Chem Biol 2013; 8:2366-71. [PMID: 23992616 DOI: 10.1021/cb4003859] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fluorescent sensors are powerful tools for visualizing and quantifying molecules and ions in living cells. A variety of small molecule and genetically encoded sensors have been developed for studying intracellular Zn(2+) homeostasis and signaling, but no direct comparisons exist, making it challenging for researchers to identify the appropriate sensor for a given application. Here we directly compare the widely used small molecule probe FluoZin-3 and a genetically encoded sensor, ZapCY2. We demonstrate that, in contrast to FluoZin-3, ZapCY2 exhibits a well-defined cytosolic localization, provides estimates of Zn(2+) concentration with little variability, does not perturb cytosolic Zn(2+) levels, and exhibits rapid Zn(2+) response dynamics. ZapCY2 was used to measure Zn(2+) concentrations in 5 different cell types, revealing higher cytosolic Zn(2+) levels in prostate cancer cells compared to normal prostate cells (although the total zinc is reduced in prostate cancer cells), suggesting distinct regulatory mechanisms.
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Affiliation(s)
- Yan Qin
- Department
of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado-Boulder, UCB 596, Boulder, Colorado 80309, United States
| | - Jose G. Miranda
- Department
of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado-Boulder, UCB 596, Boulder, Colorado 80309, United States
| | - Caitlin I. Stoddard
- Department
of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado-Boulder, UCB 596, Boulder, Colorado 80309, United States
| | - Kevin M. Dean
- Department
of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado-Boulder, UCB 596, Boulder, Colorado 80309, United States
| | - Domenico F. Galati
- Department
of Molecular, Cellular, and Developmental Biology, University of Colorado-Boulder, UCB
347, Boulder, Colorado 80309, United States
| | - Amy E. Palmer
- Department
of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado-Boulder, UCB 596, Boulder, Colorado 80309, United States
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19
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Tuncay E, Okatan EN, Vassort G, Turan B. ß-blocker timolol prevents arrhythmogenic Ca²⁺ release and normalizes Ca²⁺ and Zn²⁺ dyshomeostasis in hyperglycemic rat heart. PLoS One 2013; 8:e71014. [PMID: 23923043 PMCID: PMC3726605 DOI: 10.1371/journal.pone.0071014] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 06/25/2013] [Indexed: 01/08/2023] Open
Abstract
Defective cardiac mechanical activity in diabetes results from alterations in intracellular Ca(2+) handling, in part, due to increased oxidative stress. Beta-blockers demonstrate marked beneficial effects in heart dysfunction with scavenging free radicals and/or acting as an antioxidant. The aim of this study was to address how β-blocker timolol-treatment of diabetic rats exerts cardioprotection. Timolol-treatment (12-week), one-week following diabetes induction, prevented diabetes-induced depressed left ventricular basal contractile activity, prolonged cellular electrical activity, and attenuated the increase in isolated-cardiomyocyte size without hyperglycemic effect. Both in vivo and in vitro timolol-treatment of diabetic cardiomyocytes prevented the altered kinetic parameters of Ca(2+) transients and reduced Ca(2+) loading of sarcoplasmic reticulum (SR), basal intracellular free Ca(2+) and Zn(2+) ([Ca(2+)]i and [Zn(2+)]i), and spatio-temporal properties of the Ca(2+) sparks, significantly. Timolol also antagonized hyperphosphorylation of cardiac ryanodine receptor (RyR2), and significantly restored depleted protein levels of both RyR2 and calstabin2. Western blot analysis demonstrated that timolol-treatment also significantly normalized depressed levels of some [Ca(2+)]i-handling regulators, such as Na(+)/Ca(2+) exchanger (NCX) and phospho-phospholamban (pPLN) to PLN ratio. Incubation of diabetic cardiomyocytes with 4-mM glutathione exerted similar beneficial effects on RyR2-macromolecular complex and basal levels of both [Ca(2+)]i and [Zn(2+)]i, increased intracellular Zn(2+) hyperphosphorylated RyR2 in a concentration-dependent manner. Timolol also led to a balanced oxidant/antioxidant level in both heart and circulation and prevented altered cellular redox state of the heart. We thus report, for the first time, that the preventing effect of timolol, directly targeting heart, seems to be associated with a normalization of macromolecular complex of RyR2 and some Ca(2+) handling regulators, and prevention of Ca(2+) leak, and thereby normalization of both [Ca(2+)]i and [Zn(2+)]i homeostasis in diabetic rat heart, at least in part by controlling the cellular redox status of hyperglycemic cardiomyocytes.
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Affiliation(s)
- Erkan Tuncay
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Esma N. Okatan
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Guy Vassort
- INSERM U-1046, CHU Arnaud de Villeneuve, Montpellier, France
| | - Belma Turan
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
- * E-mail:
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20
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Yi T, Vick JS, Vecchio MJH, Begin KJ, Bell SP, Delay RJ, Palmer BM. Identifying cellular mechanisms of zinc-induced relaxation in isolated cardiomyocytes. Am J Physiol Heart Circ Physiol 2013; 305:H706-15. [PMID: 23812383 DOI: 10.1152/ajpheart.00025.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We tested several molecular and cellular mechanisms of cardiomyocyte contraction-relaxation function that could account for the reduced systolic and enhanced diastolic function observed with exposure to extracellular Zn(2+). Contraction-relaxation function was monitored in isolated rat and mouse cardiomyocytes maintained at 37°C, stimulated at 2 or 6 Hz, and exposed to 32 μM Zn(2+) or vehicle. Intracellular Zn(2+) detected using FluoZin-3 rose to a concentration of ∼13 nM in 3-5 min. Peak sarcomere shortening was significantly reduced and diastolic sarcomere length was elongated after Zn(2+) exposure. Peak intracellular Ca(2+) detected by Fura-2FF was reduced after Zn(2+) exposure. However, the rate of cytosolic Ca(2+) decline reflecting sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA2a) activity and the rate of Na(+)/Ca(2+) exchanger activity evaluated by rapid Na(+)-induced Ca(2+) efflux were unchanged by Zn(2+) exposure. SR Ca(2+) load evaluated by rapid caffeine exposure was reduced by ∼50%, and L-type calcium channel inward current measured by whole cell patch clamp was reduced by ∼70% in cardiomyocytes exposed to Zn(2+). Furthermore, ryanodine receptor (RyR) S2808 and phospholamban (PLB) S16/T17 were markedly dephosphorylated after perfusing hearts with 50 μM Zn(2+). Maximum tension development and thin-filament Ca(2+) sensitivity in chemically skinned cardiac muscle strips were not affected by Zn(2+) exposure. These findings suggest that Zn(2+) suppresses cardiomyocyte systolic function and enhances relaxation function by lowering systolic and diastolic intracellular Ca(2+) concentrations due to a combination of competitive inhibition of Ca(2+) influx through the L-type calcium channel, reduction of SR Ca(2+) load resulting from phospholamban dephosphorylation, and lowered SR Ca(2+) leak via RyR dephosphorylation. The use of the low-Ca(2+)-affinity Fura-2FF likely prevented the detection of changes in diastolic Ca(2+) and SERCA2a function. Other strategies to detect diastolic Ca(2+) in the presence of Zn(2+) are essential for future work.
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Affiliation(s)
- Ting Yi
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont
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21
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Turan B, Vassort G. Ryanodine receptor: a new therapeutic target to control diabetic cardiomyopathy. Antioxid Redox Signal 2011; 15:1847-61. [PMID: 21091075 DOI: 10.1089/ars.2010.3725] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Diabetes mellitus is a major risk factor for cardiovascular complications. Intracellular Ca(2+) release plays an important role in the regulation of muscle contraction. Sarcoplasmic reticulum Ca(2+) release is controlled by dedicated molecular machinery, composed of a complex of cardiac ryanodine receptors (RyR2s). Acquired and genetic defects in this complex result in a spectrum of abnormal Ca(2+) release phenotypes in heart. Cardiovascular dysfunction is a leading cause for mortality of diabetic individuals due, in part, to a specific cardiomyopathy, and to altered vascular reactivity. Cardiovascular complications result from multiple parameters, including glucotoxicity, lipotoxicity, fibrosis, and mitochondrial uncoupling. In diabetic subjects, oxidative stress arises from an imbalance between production of reactive oxygen and nitrogen species and capability of the system to readily detoxify reactive intermediates. To date, the etiology underlying diabetes-induced reductions in myocyte and cardiac contractility remains incompletely understood. However, numerous studies, including work from our laboratory, suggest that these defects stem in part from perturbation in intracellular Ca(2+) cycling. Since the RyR2s are one of the well-characterized redox-sensitive ion channels in heart, this article summarizes recent findings on redox regulation of cardiac Ca(2+) transport systems and discusses contributions of redox regulation to pathological cardiac function in diabetes.
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Affiliation(s)
- Belma Turan
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey .
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22
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Li Y, Hawkins BE, DeWitt DS, Prough DS, Maret W. The relationship between transient zinc ion fluctuations and redox signaling in the pathways of secondary cellular injury: relevance to traumatic brain injury. Brain Res 2010; 1330:131-41. [PMID: 20303343 DOI: 10.1016/j.brainres.2010.03.034] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 03/05/2010] [Accepted: 03/11/2010] [Indexed: 10/19/2022]
Abstract
A major obstacle that hampers the design of drug therapy for traumatic brain injury is the incomplete understanding of the biochemical pathways that lead to secondary cellular injury and contribute to cell death. One such pathway involves reactive species that generate potentially cytotoxic zinc ion fluctuations as a major executor of neuronal, and possibly glial, cell death. Whether zinc ions released during traumatic brain injury are toxic or protective is controversial but can be approached by investigating the exact concentrations of free zinc ions, the thresholds of compromised zinc buffering capacity, and the mechanism of cellular homeostatic control of zinc. Rapidly stretch-injured rat pheochromocytoma (PC12) cells express cellular zinc ion fluctuations that depend on the production of nitric oxide. Chelation of cellular zinc ions after rapid stretch injury, however, increases cellular reactive oxygen species. In a rat model of traumatic brain injury, parasagittal fluid percussion, analysis of the metal load of metallothionein was used as an indicator of changes in cellular zinc ion concentrations. The combined results from the cellular and in vivo investigations caution against interpreting zinc ion fluctuations in the early phase (24h) after injury as a primarily cytotoxic event.
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Affiliation(s)
- Yuan Li
- Division of Human Nutrition, Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston, TX 77555, USA.
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23
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Maret W. Metallothionein redox biology in the cytoprotective and cytotoxic functions of zinc. Exp Gerontol 2008; 43:363-9. [DOI: 10.1016/j.exger.2007.11.005] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Revised: 11/16/2007] [Accepted: 11/19/2007] [Indexed: 10/22/2022]
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24
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Thomas M, Vidal A, Bhattacharya SK, Ahokas RA, Sun Y, Gerling IC, Weber KT. Zinc dyshomeostasis in rats with aldosteronism. Response to spironolactone. Am J Physiol Heart Circ Physiol 2007; 293:H2361-6. [PMID: 17616752 DOI: 10.1152/ajpheart.00200.2007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Zinc is a structural constituent of many proteins, including Cu/Zn superoxide dismutase (SOD), an endogenous antioxidant enzyme. Hypozincemia has been found in patients hospitalized with congestive heart failure, where neurohormonal activation, including the renin-angiotensin-aldosterone system (RAAS), is expected and oxidative stress is present. This study was undertaken to elucidate potential pathophysiological mechanisms involved in Zn dyshomeostasis in aldosteronism. In rats receiving aldosterone/salt treatment (ALDOST) alone for 1 and 4 wk or in combination with spironolactone (Spiro), an ALDO receptor antagonist, we monitored 24-h urinary and fecal Zn excretion and tissue Zn levels in heart, liver, and skeletal muscle, together with tissue metallothionein (MT)-I, a Zn(2+)-binding protein, and Cu/Zn-SOD activities in plasma and tissues. When compared with unoperated, untreated, age-/sex-matched controls, urinary and, in particular, fecal Zn losses were markedly increased (P < 0.05) at days 7 and 28 of ALDOST, leading to hypozincemia and a fall (P < 0.05) in plasma Cu/Zn-SOD activity. Microscopic scars and perivascular fibrosis of intramural coronary arteries first appeared in the right and left ventricles at week 4 of ALDOST and were accompanied by increased (P < 0.05) tissue Zn, MT-I, and Cu/Zn-SOD activity, which were not found in uninjured liver or skeletal muscle. Spiro cotreatment prevented cardiac injury and Zn redistribution to the heart. Thus increased urinary and fecal Zn losses, together with their preferential translocation to sites of cardiac injury, where MT-I overexpression and increased Cu/Zn-SOD activity appeared, contribute to Zn dyshomeostasis in rats with aldosteronism, which were each prevented by Spiro. These findings may shed light on Zn dyshomeostasis found in patients with decompensated heart failure.
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Affiliation(s)
- Manesh Thomas
- Division of Cardiovascular Diseases, Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
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25
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Sun HS, Hui K, Lee DWK, Feng ZP. Zn2+ sensitivity of high- and low-voltage activated calcium channels. Biophys J 2007; 93:1175-83. [PMID: 17526568 PMCID: PMC1929049 DOI: 10.1529/biophysj.106.103333] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The essential cation zinc (Zn2+) blocks voltage-dependent calcium channels in several cell types, which exhibit different sensitivities to Zn2+. The specificity of the Zn2+ effect on voltage-dependent calcium channel subtypes has not been systematically investigated. In this study, we used a transient protein expression system to determine the Zn2+ effect on low- and high-voltage activated channels. We found that in Ba2+, the IC50 value of Zn2+ was alpha1-subunit-dependent with lowest value for CaV1.2, and highest for CaV3.1; the sensitivity of the channels to Zn2+ was approximately ranked as CaV1.2>CaV3.2>CaV2.3>CaV2.2=CaV 2.1>or=CaV3.3=CaV3.1. Although the CaV2.2 and CaV3.1 channels had similar IC50 for Zn2+ in Ba2+, the CaV2.2, but not CaV3.1 channels, had approximately 10-fold higher IC50 to Zn2+ in Ca2+. The reduced sensitivity of CaV2.2 channels to Zn2+ in Ca2+ was partially reversed by disrupting a putative EF-hand motif located external to the selectivity filter EEEE locus. Thus, our findings support the notion that the Zn2+ block, mediated by multiple mechanisms, may depend on conformational changes surrounding the alpha1 pore regions. These findings provide fundamental insights into the mechanism underlying the inhibitory effect of zinc on various Ca2+ channel subtypes.
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Affiliation(s)
- Hong-Shuo Sun
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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26
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Walsh BM, Naik HB, Dubach JM, Beshire M, Wieland AM, Soybel DI. Thiol-oxidant monochloramine mobilizes intracellular Ca2+ in parietal cells of rabbit gastric glands. Am J Physiol Cell Physiol 2007; 293:C1687-97. [PMID: 17287368 DOI: 10.1152/ajpcell.00189.2006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In Helicobacter pylori-induced gastritis, oxidants are generated through the interactions of bacteria in the lumen, activated granulocytes, and cells of the gastric mucosa. In this study we explored the ability of one such class of oxidants, represented by monochloramine (NH(2)Cl), to serve as agonists of Ca(2+) accumulation within the parietal cell of the gastric gland. Individual gastric glands isolated from rabbit mucosa were loaded with fluorescent reporters for Ca(2+) in the cytoplasm (fura-2 AM) or intracellular stores (mag-fura-2 AM). Conditions were adjusted to screen out contributions from metal cations such as Zn(2+), for which these reporters have affinity. Exposure to NH(2)Cl (up to 200 microM) led to dose-dependent increases in intracellular Ca(2+) concentration ([Ca(2+)](i)), in the range of 200-400 nM above baseline levels. These alterations were prevented by pretreatment with the oxidant scavenger vitamin C or a thiol-reducing agent, dithiothreitol (DTT), which shields intracellular thiol groups from oxidation by chlorinated oxidants. Introduction of vitamin C during ongoing exposure to NH(2)Cl arrested but did not reverse accumulation of Ca(2+) in the cytoplasm. In contrast, introduction of DTT or N-acetylcysteine permitted arrest and partial reversal of the effects of NH(2)Cl. Accumulation of Ca(2+) in the cytoplasm induced by NH(2)Cl is due to release from intracellular stores, entry from the extracellular fluid, and impaired extrusion. Ca(2+)-handling proteins are susceptible to oxidation by chloramines, leading to sustained increases in [Ca(2+)](i). Under certain conditions, NH(2)Cl may act not as an irritant but as an agent that activates intracellular signaling pathways. Anti-NH(2)Cl strategies should take into account different effects of oxidant scavengers and thiol-reducing agents.
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Affiliation(s)
- Breda M Walsh
- Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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Abstract
Zinc/cysteine coordination environments in proteins are redox-active. Oxidation of the sulfur ligands mobilizes zinc, while reduction of the oxidized ligands enhances zinc binding, providing redox control over the availability of zinc ions. Some zinc proteins are redox sensors, in which zinc release is coupled to conformational changes that control varied functions such as enzymatic activity, binding interactions, and molecular chaperone activity. Whereas the released zinc ion in redox sensors has no known function, the redox signal is transduced to specific and sensitive zinc signals in redox transducers. Released zinc can bind to sites on other proteins and modulate signal transduction, generation of metabolic energy, mitochondrial function, and gene expression. The paradigm of such redox transducers is the zinc protein metallothionein, which, together with its apoprotein, thionein, functions at a central node in cellular signaling by redistributing cellular zinc, presiding over the availability of zinc, and interconverting redox and zinc signals. In this regard, the transduction of nitric oxide (NO) signals into zinc signals by metallothionein has received particular attention. It appears that redox-inert zinc has been chosen to control some aspects of cellular thiol/disulfide redox metabolism. Tight control of zinc is essential for redox homeostasis because both increases and decreases of cellular zinc elicit oxidative stress. Depending on its availability, zinc can be cytoprotective as a pro-antioxidant or cytotoxic as a pro-oxidant. Any condition with acute or chronic oxidative stress is expected to perturb zinc homeostasis.
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Affiliation(s)
- Wolfgang Maret
- Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston, 77555, USA.
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Xie H, Zhu PH. Biphasic modulation of ryanodine receptors by sulfhydryl oxidation in rat ventricular myocytes. Biophys J 2006; 91:2882-91. [PMID: 16877504 PMCID: PMC1578479 DOI: 10.1529/biophysj.106.087338] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
To understand better the modulation of ryanodine receptors (RyRs) during oxidative stress, the effect of 4,4'-dithiodipyridine (DTDP), a cell-permeant and thiol-reactive oxidant, on global Ca(2+) signal and spontaneous Ca(2+) sparks of rat ventricular myocytes was investigated. It was shown that a brief Ca(2+) transient was elicited by DTDP, when its concentration was raised to 100 microM DTDP. In addition a dose-dependent increase of cytoplasmic free Zn(2+) concentration was induced by DTDP. An increase of the frequency of spontaneous Ca(2+) sparks appeared at 3 microM DTDP, whereas higher concentration of DTDP caused a biphasic change of the frequency in both intact and permeabilized myocytes. Consistent with the biphasic effect, caffeine-induced Ca(2+) transients were similarly affected. Because DTDP did not reduce the free Ca(2+) concentration in the sarcoplasmic reticulum lumen, it is likely that the effects of DTDP on the frequency and caffeine-induced Ca(2+) transients are due mainly to sulfhydryl oxidation-induced activation and subsequent inactivation of RyRs. Unlike the frequency, the spatio-temporal properties of Ca(2+) sparks were not influenced by DTDP. The finding that DTDP does not affect the duration of Ca(2+) sparks is inconsistent with that the DTDP-induced increase of the open time of reconstituted RyR channels. The mechanism underlying this discrepancy, especially the possible role of the interaction between arrayed RyRs in myocytes, is discussed. This study suggests that, even if oxidative stress is mild enough not to cause intracellular Ca(2+) accumulation, it may affect signaling pathways through directly modulating the RyR or its complex and in turn changing the frequency of spontaneous Ca(2+) sparks. Thus, the functional importance of moderate oxidative stress should not be overlooked.
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Affiliation(s)
- Hong Xie
- Unit of Cell Signal Transduction, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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Ayaz M, Turan B. Selenium prevents diabetes-induced alterations in [Zn2+]iand metallothionein level of rat heart via restoration of cell redox cycle. Am J Physiol Heart Circ Physiol 2006; 290:H1071-80. [PMID: 16214842 DOI: 10.1152/ajpheart.00754.2005] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Intracellular free zinc concentration ([Zn2+]i) is very important for cell functions, and its excessive accumulation is cytotoxic. [Zn2+]ican increase rapidly in cardiomyocytes because of mobilization of Zn2+from intracellular stores by reactive oxygen species (ROS). Moreover, ROS have been proposed to contribute to direct and/or indirect damage to cardiomyocytes in diabetes. To address these hypotheses, we investigated how elevated [Zn2+]iin cardiomyocytes could contribute to diabetes-induced alterations in intracellular free calcium concentration ([Ca2+]i). We also investigated its relationship to the changes of metallothionein (MT) level of the heart. Cardiomyocytes from normal rats loaded with fura-2 were used to fluorometrically measure resting [Zn2+]i(0.52 ± 0.06 nM) and [Ca2+]i(26.53 ± 3.67 nM). Fluorescence quenching by the heavy metal chelator N, N, N′, N′-tetrakis(2-pyridylmethyl)ethylenediamine was used to quantify [Zn2+]i. Our data showed that diabetic cardiomyocytes exhibited significantly increased [Zn2+]i(0.87 ± 0.05 nM ) and [Ca2+]i(49.66 ± 9.03 nM), decreased levels of MT and reduced glutathione, increased levels of lipid peroxidation and nitric oxide products, and decreased activities of superoxide dismutase, glutathione reductase, and glutathione peroxidase. Treatment (4 wk) of diabetic rats with sodium selenite (5 μmol·kg body wt−1·day−1) prevented these defects induced by diabetes. A comparison of present data with previously observed beneficial effects of selenium treatment on diabetes-induced contractile dysfunction of the heart can suggest that an increase in [Zn2+]imay contribute to oxidant-induced alterations of excitation-contraction coupling in diabetes. In addition, we showed that oxidative stress is involved in the etiology of diabetes-induced downregulation of heart function via depressed endogenous antioxidant defense mechanisms.
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MESH Headings
- Animals
- Calcium/metabolism
- Cells, Cultured
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/metabolism
- Female
- Male
- Myocardial Contraction/drug effects
- Myocardium/metabolism
- Myocytes, Cardiac/metabolism
- Oxidation-Reduction
- Oxidative Stress/drug effects
- Rats
- Rats, Wistar
- Reactive Oxygen Species/metabolism
- Selenium/administration & dosage
- Streptozocin
- Treatment Outcome
- Ventricular Dysfunction, Left/etiology
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/prevention & control
- Zinc/metabolism
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Affiliation(s)
- Murat Ayaz
- Department of Biophysics, School of Medicine, Ankara University, Sihhiye, 06100, Ankara, Turkey
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Costello LC, Guan Z, Franklin RB, Feng P. Metallothionein can function as a chaperone for zinc uptake transport into prostate and liver mitochondria. J Inorg Biochem 2004; 98:664-6. [PMID: 15041247 PMCID: PMC4464834 DOI: 10.1016/j.jinorgbio.2004.02.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2003] [Revised: 01/04/2004] [Accepted: 02/06/2004] [Indexed: 11/22/2022]
Abstract
In mammalian cells the cytosolic concentration of free Zn(2+) ions is extremely low (nM-fM range) and unlikely to provide an adequate pool for the uptake and accumulation of zinc in mitochondria. We previously identified a mitochondrial uptake transport process that effectively transports zinc directly from low molecular weight zinc ligands independent of and in the absence of available free Zn(2+) ions. Since metallothionein (MT) is an important ligand form of cellular zinc, we determined if Zn(7)-MT was an effective chaperone and donor for delivery and uptake of zinc by prostate and liver mitochondria. The results reveal that both intact mitochondria and mitoplasts effectively accumulated zinc from Zn(7)-MT. The study confirms and extends our previous report that the putative zinc transporter is associated with the inner mitochondrial membrane and involves a direct exchange of zinc from the ligand to the transporter. The ventral prostate cells contain no detectable MT; so that ligands (such as citrate, aspartate) other than MT are zinc donors for mitochondrial zinc accumulation. However, in liver and perhaps other cells, Zn(7)-MT is probably important in the cytosolic trafficking of zinc to the mitochondria for the uptake of zinc into the mitochondrial matrix by the putative zinc uptake transporter.
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Affiliation(s)
- Leslie C. Costello
- Corresponding authors: Tel./fax: +410-706-7340 (P. Feng); Tel./ fax: +410-706-7618 (L.C. Costello). (L.C. Costello); (P. Feng)
| | | | | | - Pei Feng
- Corresponding authors: Tel./fax: +410-706-7340 (P. Feng); Tel./ fax: +410-706-7618 (L.C. Costello). (L.C. Costello); (P. Feng)
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Jiang P, Guo Z. Fluorescent detection of zinc in biological systems: recent development on the design of chemosensors and biosensors. Coord Chem Rev 2004. [DOI: 10.1016/j.cct.2003.10.013] [Citation(s) in RCA: 739] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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