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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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Li K, Li Y, Ding H, Chen J, Zhang X. Metal-Binding Proteins Cross-Linking with Endoplasmic Reticulum Stress in Cardiovascular Diseases. J Cardiovasc Dev Dis 2023; 10:jcdd10040171. [PMID: 37103050 PMCID: PMC10143100 DOI: 10.3390/jcdd10040171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 04/11/2023] [Accepted: 04/15/2023] [Indexed: 04/28/2023] Open
Abstract
The endoplasmic reticulum (ER), an essential organelle in eukaryotic cells, is widely distributed in myocardial cells. The ER is where secreted protein synthesis, folding, post-translational modification, and transport are all carried out. It is also where calcium homeostasis, lipid synthesis, and other processes that are crucial for normal biological cell functioning are regulated. We are concerned that ER stress (ERS) is widespread in various damaged cells. To protect cells' function, ERS reduces the accumulation of misfolded proteins by activating the unfolded protein response (UPR) pathway in response to numerous stimulating factors, such as ischemia or hypoxia, metabolic disorders, and inflammation. If these stimulatory factors are not eliminated for a long time, resulting in the persistence of the UPR, it will aggravate cell damage through a series of mechanisms. In the cardiovascular system, it will cause related cardiovascular diseases and seriously endanger human health. Furthermore, there has been a growing number of studies on the antioxidative stress role of metal-binding proteins. We observed that a variety of metal-binding proteins can inhibit ERS and, hence, mitigate myocardial damage.
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Affiliation(s)
- Kejuan Li
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou 730031, China
| | - Yongnan Li
- Department of Cardiac Surgery, Lanzhou University Second Hospital, Lanzhou University, Lanzhou 730031, China
| | - Hong Ding
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou 730031, China
| | - Jianshu Chen
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou 730031, China
| | - Xiaowei Zhang
- Department of Cardiology, Lanzhou University Second Hospital, Lanzhou University, Lanzhou 730031, China
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Interplay between Zn2+ Homeostasis and Mitochondrial Functions in Cardiovascular Diseases and Heart Ageing. Int J Mol Sci 2022; 23:ijms23136890. [PMID: 35805904 PMCID: PMC9266371 DOI: 10.3390/ijms23136890] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 02/04/2023] Open
Abstract
Zinc plays an important role in cardiomyocytes, where it exists in bound and histochemically reactive labile Zn2+ forms. Although Zn2+ concentration is under tight control through several Zn2+-transporters, its concentration and intracellular distribution may vary during normal cardiac function and pathological conditions, when the protein levels and efficacy of Zn2+ transporters can lead to zinc re-distribution among organelles in cardiomyocytes. Such dysregulation of cellular Zn2+ homeostasis leads to mitochondrial and ER stresses, and interrupts normal ER/mitochondria cross-talk and mitophagy, which subsequently, result in increased ROS production and dysregulated metabolic function. Besides cardiac structural and functional defects, insufficient Zn2+ supply was associated with heart development abnormalities, induction and progression of cardiovascular diseases, resulting in accelerated cardiac ageing. In the present review, we summarize the recently identified connections between cellular and mitochondrial Zn2+ homeostasis, ER stress and mitophagy in heart development, excitation–contraction coupling, heart failure and ischemia/reperfusion injury. Additionally, we discuss the role of Zn2+ in accelerated heart ageing and ageing-associated rise of mitochondrial ROS and cardiomyocyte dysfunction.
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Olgar Y, Durak A, Bitirim CV, Tuncay E, Turan B. Insulin acts as an atypical KCNQ1/KCNE1-current activator and reverses long QT in insulin-resistant aged rats by accelerating the ventricular action potential repolarization through affecting the β 3 -adrenergic receptor signaling pathway. J Cell Physiol 2021; 237:1353-1371. [PMID: 34632595 DOI: 10.1002/jcp.30597] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 12/13/2022]
Abstract
Insufficient-heart function is associated with myocardial insulin resistance in the elderly, particularly associated with long-QT, in a dependency on dysfunctional KCNQ1/KCNE1-channels. So, we aimed to examine the contribution of alterations in KCNQ1/KCNE1-current (IKs ) to the aging-related remodeling of the heart as well as the role of insulin treatment on IKs in the aged rats. Prolonged late-phase action potential (AP) repolarization of ventricular cardiomyocytes from insulin-resistant 24-month-old rats was significantly reversed by in vitro treatment of insulin or PKG inhibitor (in vivo, as well) via recovery in depressed IKs . Although the protein level of either KCNQ1 or KCNE1 in cardiomyocytes was not affected with aging, PKG level was significantly increased in those cells. The inhibited IKs in β3 -ARs-stimulated cells could be reversed with a PKG inhibitor, indicating the correlation between PKG-activation and β3 -ARs activation. Furthermore, in vivo treatment of aged rats, characterized by β3 -ARs activation, with either insulin or a PKG inhibitor for 2 weeks provided significant recoveries in IKs , prolonged late phases of APs, prolonged QT-intervals, and low heart rates without no effect on insulin resistance. In vivo insulin treatment provided also significant recovery in increased PKG and decreased PIP2 level, without the insulin effect on the KCNQ1 level in β3 -ARs overexpressed cells. The inhibition of IKs in aged-rat cardiomyocytes seems to be associated with activated β3 -ARs dependent remodeling in the interaction between KCNQ1 and KCNE1. Significant recoveries in ventricular-repolarization of insulin-treated aged cardiomyocytes via recovery in IKs strongly emphasize two important issues: (1) IKs can be a novel target in aging-associated remodeling in the heart and insulin may be a cardioprotective agent in the maintenance of normal heart function during the aging process. (2) This study is one of the first to demonstrate insulin's benefits on long-QT in insulin-resistant aged rats by accelerating the ventricular AP repolarization through reversing the depressed IKs via affecting the β3 -ARs signaling pathway and particularly affecting activated PKG.
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Affiliation(s)
- Yusuf Olgar
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Aysegul Durak
- Department of Biophysics, 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, Ankara University, Ankara, Turkey.,Department of Biophysics, Faculty of Medicine, Lokman Hekim University, Ankara, Turkey
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Chen WB, Wang YX, Wang HG, An D, Sun D, Li P, Zhang T, Lu WG, Liu YQ. TPEN attenuates amyloid-β 25-35-induced neuronal damage with changes in the electrophysiological properties of voltage-gated sodium and potassium channels. Mol Brain 2021; 14:124. [PMID: 34384467 PMCID: PMC8359616 DOI: 10.1186/s13041-021-00837-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 08/02/2021] [Indexed: 11/10/2022] Open
Abstract
To understand the role of intracellular zinc ion (Zn2+) dysregulation in mediating age-related neurodegenerative changes, particularly neurotoxicity resulting from the generation of excessive neurotoxic amyloid-β (Aβ) peptides, this study aimed to investigate whether N, N, N', N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN), a Zn2+-specific chelator, could attenuate Aβ25-35-induced neurotoxicity and the underlying electrophysiological mechanism. We used the 3-(4, 5-dimethyl-thiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay to measure the viability of hippocampal neurons and performed single-cell confocal imaging to detect the concentration of Zn2+ in these neurons. Furthermore, we used the whole-cell patch-clamp technique to detect the evoked repetitive action potential (APs), the voltage-gated sodium and potassium (K+) channels of primary hippocampal neurons. The analysis showed that TPEN attenuated Aβ25-35-induced neuronal death, reversed the Aβ25-35-induced increase in intracellular Zn2+ concentration and the frequency of APs, inhibited the increase in the maximum current density of voltage-activated sodium channel currents induced by Aβ25-35, relieved the Aβ25-35-induced decrease in the peak amplitude of transient outward K+ currents (IA) and outward-delayed rectifier K+ currents (IDR) at different membrane potentials, and suppressed the steady-state activation and inactivation curves of IA shifted toward the hyperpolarization direction caused by Aβ25-35. These results suggest that Aβ25-35-induced neuronal damage correlated with Zn2+ dysregulation mediated the electrophysiological changes in the voltage-gated sodium and K+ channels. Moreover, Zn2+-specific chelator-TPEN attenuated Aβ25-35-induced neuronal damage by recovering the intracellular Zn2+ concentration.
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Affiliation(s)
- Wen-Bo Chen
- College of Life Sciences, Nankai University, Tianjin, 300071, People's Republic of China
| | - Yu-Xiang Wang
- Department of Immunology and Pathogenic Biology, School of Basic Medical Sciences, Hebei University of Chinese Medicine, Shijiazhuang, 050200, Hebei, People's Republic of China
| | - Hong-Gang Wang
- College of Life Sciences, Nankai University, Tianjin, 300071, People's Republic of China
| | - Di An
- College of Life Sciences, Nankai University, Tianjin, 300071, People's Republic of China
| | - Dan Sun
- College of Life Sciences, Nankai University, Tianjin, 300071, People's Republic of China
| | - Pan Li
- Tianjin Key Laboratory of Cerebral Vascular and Neurodegenerative Diseases, Tianjin Neurosurgery Institute, Department of Neurology, Tianjin Huanhu Hospital Affiliated to Nankai University, Tianjin, People's Republic of China
| | - Tao Zhang
- College of Life Sciences, Nankai University, Tianjin, 300071, People's Republic of China
| | - Wan-Ge Lu
- College of Life Sciences, Nankai University, Tianjin, 300071, People's Republic of China
| | - Yan-Qiang Liu
- College of Life Sciences, Nankai University, Tianjin, 300071, People's Republic of China.
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Durak A, Bitirim CV, Turan B. Titin and CK2α are New Intracellular Targets in Acute Insulin Application-Associated Benefits on Electrophysiological Parameters of Left Ventricular Cardiomyocytes From Insulin-Resistant Metabolic Syndrome Rats. Cardiovasc Drugs Ther 2020; 34:487-501. [PMID: 32377826 DOI: 10.1007/s10557-020-06974-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Previous studies have demonstrated that a high-carbohydrate intake could induce metabolic syndrome (MetS) in male rats with marked cardiac functional abnormalities. In addition, studies mentioned some benefits of insulin application on these complications, but there are considerable disagreements among their findings. Therefore, we aimed to extend our knowledge on the in-vitro influence of insulin on left ventricular dysfunction and also in the isolated cardiomyocytes from MetS rats. RESULTS At the organ function level, an acute insulin application (100-nM) provided an important beneficial effect on the left ventricular developed pressure in MetS rats. Furthermore, to treat the freshly isolated cardiomyocytes from MetS rats with insulin provided marked recoveries in elevated resting intracellular Ca2+-level, as well as significant prevention of prolonged action potential through an augmentation in depressed K+-channel currents. Insulin also normalized the cellular levels of increased ROS and phosphorylation of PKCα, together with normalizations of apoptotic markers in MetS cardiomyocytes through the insulin-mediated regulation of phospho-Akt. Since not only elevated PKCα-activity but also reductions in phospho-Akt are key modulators of titin-based cardiomyocyte stiffening in hyperglycemia, insulin treatment of the cardiomyocytes prevented the activation of titin via the above pathways. Furthermore, CK2α-activation and NOS-phosphorylation could be prevented with insulin treatment. Mechanistically, we found that impaired insulin signaling and elevated PKCα and CK2α activities, as well as depressed Akt phosphorylation, are key modulators of titin-based cardiomyocyte stiffening in MetS rats. CONCLUSION We propose that restoring normal kinase activities and also increases in phospho-Akt by insulin can contribute marked recoveries in MetS heart function, indicating a promising approach to modulate titin-associated factors in heart dysfunction associated with type-2 diabetes mellitus. Graphical Abstract.
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Affiliation(s)
- Aysegul Durak
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | | | - Belma Turan
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey.
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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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Olgar Y, Tuncay E, Billur D, Durak A, Ozdemir S, Turan B. Ticagrelor reverses the mitochondrial dysfunction through preventing accumulated autophagosomes-dependent apoptosis and ER stress in insulin-resistant H9c2 myocytes. Mol Cell Biochem 2020; 469:97-107. [PMID: 32301059 DOI: 10.1007/s11010-020-03731-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/07/2020] [Indexed: 12/20/2022]
Abstract
Ticagrelor, a P2Y12-receptor inhibitor, and a non-thienopyridine agent are used to treat diabetic patients via its effects on off-target mechanisms. However, the exact sub-cellular mechanisms by which ticagrelor exerts those effects remains to be elucidated. Accordingly, the present study aimed to examine whether ticagrelor influences directly the cardiomyocytes function under insulin resistance through affecting mitochondria-sarco(endo)plasmic reticulum (SER) cross-talk. Therefore, we analyzed the function and ultrastructure of mitochondria and SER in insulin resistance-mimicked (50-μM palmitic acid for 24-h) H9c2 cardiomyocytes in the presence or absence of ticagrelor (1-µM for 24-h). We found that ticagrelor treatment significantly prevented depolarization of mitochondrial membrane potential and increases in reactive oxygen species with a marked increase in the ATP level in insulin-resistant H9c2 cells. Ticagrelor treatment also reversed the increases in the resting level of free Ca2+ and mRNA level of P2Y12 receptors as well as preserved ER stress and apoptosis in insulin-resistant H9c2 cells. Furthermore, we determined marked repression with ticagrelor treatment in the increased number of autophagosomes and degeneration of mitochondrion, including swelling and loss of crista besides recoveries in enlargement and irregularity seen in SER in insulin-resistant H9c2 cells. Moreover, ticagrelor treatment could prevent the altered mRNA levels of Becklin-1 and type 1 equilibrative nucleoside transporter (ENT1), which are parallel to the preservation of ultrastructural ones. Our overall data demonstrated that ticagrelor can directly affect cardiomyocytes and provide marked protection against ER stress and dramatic induction of autophagosomes, and therefore, can alleviate the ER stress-induced oxidative stress increase and cell apoptosis during insulin resistance.
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Affiliation(s)
- Yusuf Olgar
- Departments of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Erkan Tuncay
- Departments of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Deniz Billur
- Departments of Histology-Embryology, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Aysegul Durak
- Departments of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Semir Ozdemir
- Departments of Biophysics, Faculty of Medicine, Akdeniz University, Antalya, Turkey.
| | - Belma Turan
- Departments of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey.
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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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Turan B. A Brief Overview from the Physiological and Detrimental Roles of Zinc Homeostasis via Zinc Transporters in the Heart. Biol Trace Elem Res 2019; 188:160-176. [PMID: 30091070 DOI: 10.1007/s12011-018-1464-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/26/2018] [Indexed: 12/15/2022]
Abstract
Zinc (mostly as free/labile Zn2+) is an essential structural constituent of many proteins, including enzymes in cellular signaling pathways via functioning as an important signaling molecule in mammalian cells. In cardiomyocytes at resting condition, intracellular labile Zn2+ concentration ([Zn2+]i) is in the nanomolar range, whereas it can increase dramatically under pathological conditions, including hyperglycemia, but the mechanisms that affect its subcellular redistribution is not clear. Therefore, overall, very little is known about the precise mechanisms controlling the intracellular distribution of labile Zn2+, particularly via Zn2+ transporters during cardiac function under both physiological and pathophysiological conditions. Literature data demonstrated that [Zn2+]i homeostasis in mammalian cells is primarily coordinated by Zn2+ transporters classified as ZnTs (SLC30A) and ZIPs (SLC39A). To identify the molecular mechanisms of diverse functions of labile Zn2+ in the heart, the recent studies focused on the discovery of subcellular localization of these Zn2+ transporters in parallel to the discovery of novel physiological functions of [Zn2+]i in cardiomyocytes. The present review summarizes the current understanding of the role of [Zn2+]i changes in cardiomyocytes under pathological conditions, and under high [Zn2+]i and how Zn2+ transporters are important for its subcellular redistribution. The emerging importance and the promise of some Zn2+ transporters for targeted cardiac therapy against pathological stimuli are also provided. Taken together, the review clearly outlines cellular control of cytosolic Zn2+ signaling by Zn2+ transporters, the role of Zn2+ transporters in heart function under hyperglycemia, the role of Zn2+ under increased oxidative stress and ER stress, and their roles in cancer are discussed.
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Affiliation(s)
- Belma Turan
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey.
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11
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Tuncay E, Olgar Y, Durak A, Degirmenci S, Bitirim CV, Turan B. β 3 -adrenergic receptor activation plays an important role in the depressed myocardial contractility via both elevated levels of cellular free Zn 2+ and reactive nitrogen species. J Cell Physiol 2019; 234:13370-13386. [PMID: 30613975 DOI: 10.1002/jcp.28015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 12/11/2018] [Indexed: 12/27/2022]
Abstract
Role of β3 -AR dysregulation, as either cardio-conserving or cardio-disrupting mediator, remains unknown yet. Therefore, we examined the molecular mechanism of β3 -AR activation in depressed myocardial contractility using a specific agonist CL316243 or using β3 -AR overexpressed cardiomyocytes. Since it has been previously shown a possible correlation between increased cellular free Zn2+ ([Zn2+ ]i ) and depressed cardiac contractility, we first demonstrated a relation between β3 -AR activation and increased [Zn2+ ]i , parallel to the significant depolarization in mitochondrial membrane potential in rat ventricular cardiomyocytes. Furthermore, the increased [Zn2+ ]i induced a significant increase in messenger RNA (mRNA) level of β3 -AR in cardiomyocytes. Either β3 -AR activation or its overexpression could increase cellular reactive oxygen species (ROS) and reactive nitrogen species (RNS) levels, in line with significant changes in nitric oxide (NO)-pathway, including increases in the ratios of pNOS3/NOS3 and pGSK-3β/GSK-3β, and PKG expression level in cardiomyocytes. Although β3 -AR activation induced depression in both Na+ - and Ca2+ -currents, the prolonged action potential (AP) seems to be associated with a marked depression in K+ -currents. The β3 -AR activation caused a negative inotropic effect on the mechanical activity of the heart, through affecting the cellular Ca2+ -handling, including its effect on Ca2+ -leakage from sarcoplasmic reticulum (SR). Our cellular level data with β3 -AR agonism were supported with the data on high [Zn2+ ]i and β3 -AR protein-level in metabolic syndrome (MetS)-rat heart. Overall, our present data can emphasize the important deleterious effect of β3 -AR activation in cardiac remodeling under pathological condition, at least, through a cross-link between β3 -AR activation, NO-signaling, and [Zn2+ ]i pathways. Moreover, it is interesting to note that the recovery in ER-stress markers with β3 -AR agonism in hyperglycemic cardiomyocytes is favored. Therefore, how long and to which level the β3 -AR agonism would be friend or become foe remains to be mystery, yet.
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Affiliation(s)
- Erkan Tuncay
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Yusuf Olgar
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Aysegul Durak
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Sinan Degirmenci
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
| | | | - Belma Turan
- Department of Biophysics, Ankara University Faculty of Medicine, Ankara, Turkey
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Durak A, Olgar Y, Degirmenci S, Akkus E, Tuncay E, Turan B. A SGLT2 inhibitor dapagliflozin suppresses prolonged ventricular-repolarization through augmentation of mitochondrial function in insulin-resistant metabolic syndrome rats. Cardiovasc Diabetol 2018; 17:144. [PMID: 30447687 PMCID: PMC6240275 DOI: 10.1186/s12933-018-0790-0] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 11/14/2018] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Metabolic syndrome (MetS) is a prevalent risk factor for cardiac dysfunction. Although SGLT2-inhibitors have important cardioprotective effects in hyperglycemia, their underlying mechanisms are complex and not completely understood. Therefore, we examined mechanisms of a SGLT2-inhibitor dapagliflozin (DAPA)-related cardioprotection in overweight insulin-resistant MetS-rats comparison with insulin (INSU), behind its glucose-lowering effect. METHODS A 28-week high-carbohydrate diet-induced MetS-rats received DAPA (5 mg/kg), INSU (0.15 mg/kg) or vehicle for 2 weeks. To validate MetS-induction, we monitored all animals weekly by measuring body weight, blood glucose and HOMO-IR index, electrocardiograms, heart rate, systolic and diastolic pressures. RESULTS DAPA-treatment of MetS-rats significantly augmented the increased blood pressure, prolonged Q-R interval, and low heart rate with depressed left ventricular function and relaxation of the aorta. Prolonged-action potentials were preserved with DAPA-treatment, more prominently than INSU-treatment, at most, through the augmentation in depressed voltage-gated K+-channel currents. DAPA, more prominently than INSU-treatment, preserved the depolarized mitochondrial membrane potential, and altered mitochondrial protein levels such as Mfn-1, Mfn-2, and Fis-1 as well as provided significant augmentation in cytosolic Ca2+-homeostasis. Furthermore, DAPA also induced significant augmentation in voltage-gated Na+-currents and intracellular pH, and the cellular levels of increased oxidative stress, protein-thiol oxidation and ADP/ATP ratio in cardiomyocytes from MetS rats. Moreover, DAPA-treatment normalized the increases in the mRNA level of SGLT2 in MetS-rat heart. CONCLUSIONS Overall, our data provided a new insight into DAPA-associated cardioprotection in MetS rats, including suppression of prolonged ventricular-repolarization through augmentation of mitochondrial function and oxidative stress followed by improvement of fusion-fission proteins, out of its glucose-lowering effect.
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Affiliation(s)
- Aysegul Durak
- Departments of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Yusuf Olgar
- Departments of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Sinan Degirmenci
- Departments of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Erman Akkus
- Internal Medicine, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Erkan Tuncay
- Departments of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Belma Turan
- Departments of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey.
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