26
|
Andreadou I, Schulz R, Papapetropoulos A, Turan B, Ytrehus K, Ferdinandy P, Daiber A, Di Lisa F. The role of mitochondrial reactive oxygen species, NO and H 2 S in ischaemia/reperfusion injury and cardioprotection. J Cell Mol Med 2020; 24:6510-6522. [PMID: 32383522 PMCID: PMC7299678 DOI: 10.1111/jcmm.15279] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/04/2020] [Accepted: 03/08/2020] [Indexed: 12/12/2022] Open
Abstract
Redox signalling in mitochondria plays an important role in myocardial ischaemia/reperfusion (I/R) injury and in cardioprotection. Reactive oxygen and nitrogen species (ROS/RNS) modify cellular structures and functions by means of covalent changes in proteins including among others S‐nitros(yl)ation by nitric oxide (NO) and its derivatives, and S‐sulphydration by hydrogen sulphide (H2S). Many enzymes are involved in the mitochondrial formation and handling of ROS, NO and H2S under physiological and pathological conditions. In particular, the balance between formation and removal of reactive species is impaired during I/R favouring their accumulation. Therefore, various interventions aimed at decreasing mitochondrial ROS accumulation have been developed and have shown cardioprotective effects in experimental settings. However, ROS, NO and H2S play also a role in endogenous cardioprotection, as in the case of ischaemic pre‐conditioning, so that preventing their increase might hamper self‐defence mechanisms. The aim of the present review was to provide a critical analysis of formation and role of reactive species, NO and H2S in mitochondria, with a special emphasis on mechanisms of injury and protection that determine the fate of hearts subjected to I/R. The elucidation of the signalling pathways of ROS, NO and H2S is likely to reveal novel molecular targets for cardioprotection that could be modulated by pharmacological agents to prevent I/R injury.
Collapse
|
27
|
Olgar Y, Billur D, Tuncay E, Turan B. MitoTEMPO provides an antiarrhythmic effect in aged-rats through attenuation of mitochondrial reactive oxygen species. Exp Gerontol 2020; 136:110961. [PMID: 32325093 DOI: 10.1016/j.exger.2020.110961] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/16/2020] [Accepted: 04/03/2020] [Indexed: 01/08/2023]
Abstract
The death prevalence from cardiovascular disease is significantly high in elderly-populations, while mitochondrial-aging plays an important in abnormal function of vital organs through high mitochondrial ROS production. Mitochondria have a unique mode of action by providing ATP production and modulating the cytosolic Ca2+-signaling and maintain the redox status of cardiomyocytes. There is an aging-associated impairment in oxidative phosphorylation which causes a marked dysregulation of mitochondrial biogenesis. Therefore, we aimed to examine whether a mitochondria-targeting antioxidant, MitoTEMPO, can directly provide a cardioprotective effect on ventricular cardiomyocyte function under in vitro conditions. The MitoTEMPO-treatment (0.1 μM for 4-h) of aged-ventricular cardiomyocytes (from 24-mo-old rats), compared to those of the adults (from 8-mo-old rats) markedly augmented not only the depressed biochemical parameters but also the ultrastructure of mitochondria. It also provided marked protective action against increased mitochondrial superoxide formation and Bnip3 overexpression, which both markedly induce depolarized mitochondrial potential, increase reactive oxygen species, mitochondrial swelling and fission, and accelerate mitochondrial turnover via autophagy. Furthermore, it provided marked protection against spontaneous action potentials, via shortening the prolonged action potential duration, at most, through recovery in depressed K+-channel currents. Moreover, we determined significant recovery in the depressed intracellular Ca2+-changes under electrical stimulation in MitoTEMPO-treated the aged-cardiomyocytes. Overall, we provided important information associated with an antiarrhythmic action, thereby controlling cytosolic and mitochondrial Ca2+-handling, implying its possible protective role of mitochondria-targeting antioxidant-treatment during aging.
Collapse
|
28
|
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.
Collapse
|
29
|
Turan B, Olgar Y, Durak A, Tuncay E. Insulin Similar to Activator of KCNQ1 Channel Recovers the Prolonged Repolarization of Ventricular Cardiomyocytes from Insulin Resistant Aged Rats. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.07489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
30
|
Tuncay E, Turan B. The Zn
2+
‐Transporter ZnT6 Plays Important Role on Regulation of Cytosolic Free Zn
2+
Through Modulation of Mitochondrial Zn
2+
in Hyperglycemic Cardiomyocytes. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.00265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
31
|
Makrecka‐Kuka M, Liepinsh E, Murray AJ, Lemieux H, Dambrova M, Tepp K, Puurand M, Käämbre T, Han WH, Goede P, O'Brien KA, Turan B, Tuncay E, Olgar Y, Rolo AP, Palmeira CM, Boardman NT, Wüst RCI, Larsen TS. Altered mitochondrial metabolism in the insulin-resistant heart. Acta Physiol (Oxf) 2020; 228:e13430. [PMID: 31840389 DOI: 10.1111/apha.13430] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 12/05/2019] [Accepted: 12/06/2019] [Indexed: 12/12/2022]
Abstract
Obesity-induced insulin resistance and type 2 diabetes mellitus can ultimately result in various complications, including diabetic cardiomyopathy. In this case, cardiac dysfunction is characterized by metabolic disturbances such as impaired glucose oxidation and an increased reliance on fatty acid (FA) oxidation. Mitochondrial dysfunction has often been associated with the altered metabolic function in the diabetic heart, and may result from FA-induced lipotoxicity and uncoupling of oxidative phosphorylation. In this review, we address the metabolic changes in the diabetic heart, focusing on the loss of metabolic flexibility and cardiac mitochondrial function. We consider the alterations observed in mitochondrial substrate utilization, bioenergetics and dynamics, and highlight new areas of research which may improve our understanding of the cause and effect of cardiac mitochondrial dysfunction in diabetes. Finally, we explore how lifestyle (nutrition and exercise) and pharmacological interventions can prevent and treat metabolic and mitochondrial dysfunction in diabetes.
Collapse
|
32
|
Okatan EN, Olgar Y, Tuncay E, Turan B. Azoramide improves mitochondrial dysfunction in palmitate-induced insulin resistant H9c2 cells. Mol Cell Biochem 2019; 461:65-72. [PMID: 31327095 DOI: 10.1007/s11010-019-03590-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/13/2019] [Indexed: 12/23/2022]
Abstract
Azoramide is identified as a new compound with the dual properties for the improvement of ER-folding capacity in various cells as well as for the treatment of T2DM. Although the effect of azoramide in glucose-homeostasis in mammalians is not known very well, a limited number of experimental studies showed that it could improve the insulin sensitivity in genetically obese mice. Therefore, here, we aimed to investigate the direct effect of azoramide on insulin signaling in insulin-resistant (IR) cardiomyocytes using IR-modelled ventricular cardiomyocytes. This model was established in H9c2 cells using palmitic acid incubation (50-μM for 24-h). The development of IR in cells was verified by monitoring the cellular 2-DG6P uptake assays in these treated cells. The 2-DG6P uptake was 50% less in the IR-cells compared to the control cells, while azoramide treatment (20-μM for 48-h) could prevent fully that decrease. In addition, azoramide treatment markedly preserved the IR-induced less ATP production and high-ROS production in these IR-cells. Furthermore, this treatment prevented the functional changes in mitochondria characterized by depolarized mitochondrial membrane potential and mitochondrial fusion or fusion-related protein levels as well as cellular ATP level. Moreover, this treatment provided marked protection against IR-associated changes in the insulin signaling pathway in cells, including recovery in the phosphorylation of IRS1 and Akt as well as the protein level of GLUT4 and Akt. Our present results, for the first time, demonstrated that azoramide plays an important protective role in IR-cardiomyocytes, at most, protective action on mitochondria. Therefore, one can suggest that azoramide, as a novel regulator, can provide direct cardioprotection in the IR-heart, at most, via affecting mitochondria and can be a good candidate as a new drug for the treatment of IR-associated cardiovascular disorders in mammalians with systemic IR.
Collapse
|
33
|
Okatan EN, Turan B. The contribution of phosphodiesterases to cardiac dysfunction in rats with metabolic syndrome induced by a high-carbohydrate diet. Can J Physiol Pharmacol 2019; 97:1064-1072. [PMID: 31299169 DOI: 10.1139/cjpp-2019-0006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Metabolic syndrome (MetS) is a cluster of risk factors, including insulin resistance among others, underlying the development of diabetes and (or) cardiovascular diseases. Studies show a close relationship between cardiac dysfunction and abnormal cAMP catabolism, which contributes to pathological remodelling. Stimulating the synthesis of cAMP via suppression of phosphodiesterases (PDEs) has positive therapeutic effects. Therefore, we examined the role of PDEs on cardiac dysfunction in high-carbohydrate diet-induced MetS rats. We first demonstrated significantly high expression levels of PDE3 and PDE4, the most highly expressed subtypes, together with depressed cAMP levels in heart tissue from MetS rats. Second, we demonstrated the activity of these PDEs by using either their basal or PDE inhibitor-induced intracellular levels of cAMP and Ca2+, the transient intracellular Ca2+ changes under electrical stimulation, isometric contractions in papillary muscle strips and some key signalling proteins (such as RyR2, PLN, PP1A, and PKA) are responsible for the Ca2+ homeostasis in isolated cardiomyocytes from MetS rats. The clear recovery in decreased basal cAMP levels, increased protein expression levels of PDE3 and PDE4, and positive responses in the altered Ca2+ homeostasis to PDE inhibitors as seen in our study can provide important insights about the roles of activated PDEs in depressed contractile activity in hearts from MetS rats.
Collapse
|
34
|
Ulusu NN, Gok M, Erman B, Turan B. Effects of Timolol Treatment on Pancreatic Antioxidant Enzymes in Streptozotocin-induced Diabetic Rats: An Experimental and Computational Study. J Med Biochem 2019; 38:306-316. [PMID: 31156341 PMCID: PMC6534949 DOI: 10.2478/jomb-2018-0034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 09/18/2018] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND The study aimed to investigate whether timolol-treatment has a beneficial effect on pentose phosphate pathway enzyme activities such as glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGDH) enzyme activities and cAMP level in streptozotocin-induced diabetic rats in pancreatic tissues. METHODS Diabetes was induced by streptozotocin (STZ) in 3-month old male Wistar rats. The diabetic rats were treated with timolol (5 mg/kg body weight, for 12 weeks) while the control group received saline. Enzyme activities were determined in pancreas tissue. To support our results, we performed in silico calculations, using Protein Data Bank structures. RESULTS Timolol treatment of STZ-induced diabetic rats had no noteworthy effect on high blood-glucose levels. However, this treatment induced activities of G6PD and 6PGDH in diabetic rats. Timolol treatment significantly increased cAMP level in diabetic pancreatic tissue. We found that timolol cannot bind strongly to either G6PD or 6PGD, but there is a relatively higher binding affinity to adenylyl cyclase, responsible for cAMP production, serving as a regulatory signal via specific cAMP-binding proteins. CONCLUSIONS Our data point out that timolol treatment has beneficial effects on the antioxidant defence mechanism enzymes in the pancreas of STZ-induced diabetic rats.
Collapse
|
35
|
Koc E, Olgar Y, Turan B. MitoTEMPO Increases the Gastrointestinal Motility in Aged Rats. CYPRUS JOURNAL OF MEDICAL SCIENCES 2019. [DOI: 10.5152/cjms.2019.747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
36
|
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.
Collapse
|
37
|
Turan B, Olgar Y, Tuncay E. Inhibiton of Protein Kinase G Preserves Prolonged Ventricular Action Potentials via Improvement of Slow-Activated Voltage-Dependent K+-Channel Currents in Aged Rat Cardiomyocytes. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
38
|
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.
Collapse
|
39
|
Tuncay E, Bitirim CV, Olgar Y, Durak A, Rutter GA, Turan B. Zn2+-transporters ZIP7 and ZnT7 play important role in progression of cardiac dysfunction via affecting sarco(endo)plasmic reticulum-mitochondria coupling in hyperglycemic cardiomyocytes. Mitochondrion 2019; 44:41-52. [DOI: 10.1016/j.mito.2017.12.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/13/2017] [Accepted: 12/27/2017] [Indexed: 12/20/2022]
|
40
|
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.
Collapse
|
41
|
Olgar Y, Turan B. A sodium-glucose cotransporter 2 (SGLT2) inhibitor dapagliflozin comparison with insulin shows important effects on Zn 2+-transporters in cardiomyocytes from insulin-resistant metabolic syndrome rats through inhibition of oxidative stress 1. Can J Physiol Pharmacol 2018; 97:528-535. [PMID: 30444646 DOI: 10.1139/cjpp-2018-0466] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Sodium-glucose cotransporter 2 (SGLT2) inhibitors showed significant effects in patients with diabetes or metabolic syndrome (MetS) with high cardiovascular risk. Although the increased intracellular Zn2+ level ([Zn2+]i), oxidative stress, and altered cardiac matrix metalloproteinases (MMPs) in diabetic cardiomyopathy can intersect with different signaling pathways, the exact mechanisms are not known yet. Since either MMPs or SGLT2 have important roles in cardiac-fibrosis under hyperglycemia, we aimed to examine the role of SGLT2 inhibitor dapagliflozin (DAP) on cardiac Zn2+-transporters responsible for [Zn2+]i-regulation, comparison to insulin (INS), together with MMP levels and systemic oxidative stress status in MetS-rats. High-carbohydrated diet-induced MetS-rats received DAP or INS for 2 weeks. DAP but not INS in MetS-rats significantly decreased high blood-glucose levels, while both treatments exerted benefits on increased total oxidative status and decreased total antioxidant status in MetS-rat plasma as well as in heart tissue. Protein levels of Zn2+-transporters, responsible for Zn2+-influx into cytosol, ZIP7 and ZIP14 were increased with significant decrease in ZIP8 of MetS-rat cardiomyoctes, while Zn2+-transporters, responsible for cytosolic Zn2+-efflux, ZnT7 was decreased with no change in ZnT8. Both treatments induced significant beneficial effects on altered ZIP14, ZIP8, and ZnT7 levels. Furthermore, both treatments exerted benefits on depressed gelatin-zymography and protein expression levels of MMP-2 and MMP-9 in MetS-rat ventricular cardiomyocytes. The direct effect of DAP on heart was also confirmed with measurements of left ventricular developed pressure. Overall, we showed that DAP has important antioxidant-like cardio-protective effects in MetS-rats, similar to INS-effect, affecting Zn2+-regulation via Zn2+-transporters, MMPs, and oxidative stress. Therefore one can suggest that SGLT2 inhibitors can be new therapeutic agents for cardio-protection not only in hyperglycemia but also in failing heart.
Collapse
|
42
|
Bilginoglu A, Selcuk MFT, Nakkas H, Turan B. Pioglitazone provides beneficial effect in metabolic syndrome rats via affecting intracellular Na + Dyshomeostasis. J Bioenerg Biomembr 2018; 50:437-445. [PMID: 30361824 DOI: 10.1007/s10863-018-9776-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 10/17/2018] [Indexed: 02/06/2023]
Abstract
Metabolic syndrome, is associated impaired blood glucose level, insulin resistance, and dyslipidemia caused by abdominal obesity. Also, it is related with cardiovascular risk accumulation and cardiomyopathy. The hypothesis of this study was to examine the effect of thiazolidinediones such as pioglitazone on intracellular Na+ homeostasis in heart of metabolic syndrome male rats. Abdominal obesity and glucose intolerance had measured as a marker of metabolic syndrome. Intracellular Na+ concentration ([Na+]i) at rest and [Na+]i during pacing with electrical field stimulation were determined in freshly isolated cardiomyocytes. Also, TTX-sensitive Na+- channel current (INa) density and I-V characteristics of these channels were measured to understand [Na+]i homeostasis. We determined the protein levels of Na+/Ca2+ exchanger and Na+-K+ pump to understand the relation between [Na+]i homeostasis. High sucrose intake significantly increased body mass and blood glucose level of the rats in the metabolic syndrome group as compared with control group. There was a decrease in INa density and there were differences in points on activation curve of INa. Basal [Na+]i in metabolic syndrome group significantly increased but there was a significantly decrease in [Na+]i in stimulated cardiomyocytes in metabolic syndrome. Furthermore, pioglitazone induced decreases in the basal [Na+]i and preserved the decrease in INa and [Na+]i in stimulated cardiomyocytes to those of controls. Histologically, metabolic syndrome affected heart and associated tissues together with many other organs. Results of the present study suggest that pioglitazone has significant beneficial effects on metabolic syndrome associated disturbances in the heart via effecting Na+ homeostasis in cardiomyocytes.
Collapse
|
43
|
Degirmenci S, Olgar Y, Durak A, Tuncay E, Turan B. Cytosolic increased labile Zn 2+ contributes to arrhythmogenic action potentials in left ventricular cardiomyocytes through protein thiol oxidation and cellular ATP depletion. J Trace Elem Med Biol 2018; 48:202-212. [PMID: 29773183 DOI: 10.1016/j.jtemb.2018.04.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/12/2018] [Accepted: 04/12/2018] [Indexed: 02/06/2023]
Abstract
Intracellular labile (free) Zn2+-level ([Zn2+]i) is low and increases markedly under pathophysiological conditions in cardiomyocytes. High [Zn2+]i is associated with alterations in excitability and ionic-conductances while exact mechanisms are not clarified yet. Therefore, we examined the elevated-[Zn2+]i on some sarcolemmal ionic-mechanisms, which can mediate cardiomyocyte dysfunction. High-[Zn2+]i induced significant changes in action potential (AP) parameters, including depolarization in resting membrane-potential and prolongations in AP-repolarizing phases. We detected also the time-dependent effects such as induction of spontaneous APs at the time of ≥ 3 min following [Zn2+]i increases, a manner of cellular ATP dependent and reversible with disulfide-reducing agent dithiothreitol, DTT. High-[Zn2+]i induced inhibitions in voltage-dependent K+-channel currents, such as transient outward K+-currents, Ito, steady-state currents, Iss and inward-rectifier K+-currents, IK1, reversible with DTT seemed to be responsible from the prolongations in APs. We, for the first time, demonstrated that lowering cellular ATP level induced significant decreaeses in both Iss and IK1, while no effect on Ito. However, the increased-[Zn2+]i could induce marked activation in ATP-sensitive K+-channel currents, IKATP, depending on low cellular ATP and thiol-oxidation levels of these channels. The mRNA levels of Kv4.3, Kv1.4 and Kv2.1 were depressed markedly with increased-[Zn2+]i with no change in mRNA level of Kv4.2, while the mRNA level of IKATP subunit, SUR2A was increased significantly with increased-[Zn2+]i, being reversible with DTT. Overall we demonstrated that high-[Zn2+]i, even if nanomolar levels, alters cardiac function via prolonged APs of cardiomyocytes, at most, due to inhibitions in voltage-dependent K+-currents, although activation of IKATP is playing cardioprotective role, through some biochemical changes in cellular ATP- and thiol-oxidation levels. It seems, a well-controlled [Zn2+]i can be novel therapeutic target for cardiac complications under pathological conditions including oxidative stress.
Collapse
|
44
|
Önder A, Adanır AS, Bilaç Ö, Kavurma C, Doğan Y, Sapmaz ŞY, Türkmen NB, Tekeş FA, Arslan R, Kurtses Gürsoy B, Öztürk B, Işıldar Y, Uzunoğlu GB, Bilgen N, Doğan B, Duman A, Memiş ÇÖ, Kocabaş O, Sevinçok L, Üçel Uİ, Demir Özkay Ü, Can ÖD, Akpınar K, Özdel Oİ, Bora ST, Buldukoğlu K, Karatoprak S, Dönmez YE, Özcan Ö, Altun H, Altun İ, Ardic FC, Kose S, Solmaz M, Kulacaoglu F, Balcioglu YH, Olğar Y, Turan B, Öztürk Y, Gelegen V, Tamam L, Aslan Ş, Çamlı N, Topak OZ, Tümkaya S, Ateşci FÇ, Metin O, Ray PC, Kaypakli GY, Eynalli E, Tahiroglu AY, Karci CK, Celik GG, Çimik A, Alyu F, Zıblak A, Kenar ANİ, Yücel NT, Barbaros MB, Eker D, Çimen E, Gündoğmuş İ, Algül A, Karagöz A, Kıyançiçek M, Kalcı P, Karaş H, Polat A, Alğan Z, İbiloğlu AO, İbiloglu İ, Aslaner D, Comlekci M, Sagir S, Basoglu T, Özen ME, Örüm MH, Kalenderoğlu A, Peltek G, Selek S, Atmaca M, Vural M, Aydın H, Yılmaz S, Öner Rİ, Karadağ AS, Kara MZ, Usta MB, Karabekiroğlu K, Şahin B, Aydın M, Bozkurt A, Karaosman T, Aral A, Çobanoğlu C, Kurt AD, Kesim N, Şahin İ, Ürer E, Eğilmez OB, Utkan T, Sahin TD, Gocmez SS, Yazir Y, Aricioglu F, Yurtdaş C, Zortul H, Yilmaz B, Arıcıoğlu F, Parlaktaş HK, Uçar AY, Yılmaz B, Kurtul N, Arıcı A, Yazar EM, Uzun N, Akça ÖF, Kılınç İ, Balcı T, Bayru O, Bertizlioğlu O, Yalçın FY, Bolu A, Akar H, Aydın MS, Doruk A, Mutu T, Yazici E, Guzel D, Erol A, Çiftçi E, Kaya H, Güleç H, Salah AA, Kalyoncu T, Çıldır DA, Ergüvendi F, Shamkhalova U, Gok EE, Altunbasak S, Dogankoc SB, Ovetti NHC, Metin Ö, Shamkhalova U. Poster Presentations. PSYCHIAT CLIN PSYCH 2018. [DOI: 10.1080/24750573.2018.1465020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
|
45
|
Olgar Y, Ozdemir S, Turan B. Induction of endoplasmic reticulum stress and changes in expression levels of Zn 2+-transporters in hypertrophic rat heart. Mol Cell Biochem 2018; 440:209-219. [PMID: 28849306 DOI: 10.1007/s11010-017-3168-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [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.
Collapse
|
46
|
Durak A, Olgar Y, Tuncay E, Turan B. β3-Adrenergic Receptor Regulation of Cardiac Ion Channels in Overweight Insulin Resistant Rats. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.1727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
47
|
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.
Collapse
|
48
|
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.
Collapse
|
49
|
Olgar Y, Celen MC, Yamasan BE, Ozturk N, Turan B, Ozdemir S. Rho-kinase inhibition reverses impaired Ca 2+ handling and associated left ventricular dysfunction in pressure overload-induced cardiac hypertrophy. Cell Calcium 2017; 67:81-90. [PMID: 29029794 DOI: 10.1016/j.ceca.2017.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 08/24/2017] [Accepted: 09/09/2017] [Indexed: 10/18/2022]
|
50
|
Durak A, Olgar Y, Tuncay E, Karaomerlioglu I, Kayki Mutlu G, Arioglu Inan E, Altan VM, Turan B. Onset of decreased heart work is correlated with increased heart rate and shortened QT interval in high-carbohydrate fed overweight rats. Can J Physiol Pharmacol 2017; 95:1335-1342. [DOI: 10.1139/cjpp-2017-0054] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mechanical activity of the heart is adversely affected in metabolic syndrome (MetS) characterized by increased body mass and marked insulin resistance. Herein, we examined the effects of high carbohydrate intake on cardiac function abnormalities by evaluating in situ heart work, heart rate, and electrocardiograms (ECGs) in rats. MetS was induced in male Wistar rats by adding 32% sucrose to drinking water for 22–24 weeks and was confirmed by insulin resistance, increased body weight, increased blood glucose and serum insulin, and increased systolic and diastolic blood pressures in addition to significant loss of left ventricular integrity and increased connective tissue around myofibrils. Analysis of in situ ECG recordings showed a markedly shortened QT interval and decreased QRS amplitude with increased heart rate. We also observed increased oxidative stress and decreased antioxidant defense characterized by decreases in serum total thiol level and attenuated paraoxonase and arylesterase activities. Our data indicate that increased heart rate and a shortened QT interval concomitant with higher left ventricular developed pressure in response to β-adrenoreceptor stimulation as a result of less cyclic AMP release could be regarded as a natural compensation mechanism in overweight rats with MetS. In addition to the persistent insulin resistance and obesity associated with MetS, one should consider the decreased heart work, increased heart rate, and shortened QT interval associated with high carbohydrate intake, which may have more deleterious effects on the mammalian heart.
Collapse
|