1
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Feng C, Song J, Deng L, Zhang J, Lian X, Zhen Z, Liu J. Ginsenoside Rb1 reduces oxidative/carbonyl stress damage and dysfunction of RyR2 in the heart of streptozotocin-induced diabetic rats. BMC Cardiovasc Disord 2024; 24:333. [PMID: 38961333 PMCID: PMC11221176 DOI: 10.1186/s12872-024-04005-8] [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: 04/05/2024] [Accepted: 06/23/2024] [Indexed: 07/05/2024] Open
Abstract
BACKGROUND Oxidative stress may contribute to cardiac ryanodine receptor (RyR2) dysfunction in diabetic cardiomyopathy. Ginsenoside Rb1 (Rb1) is a major pharmacologically active component of ginseng to treat cardiovascular diseases. Whether Rb1 treat diabetes injured heart remains unknown. This study was to investigate the effect of Rb1 on diabetes injured cardiac muscle tissue and to further investigate its possible molecular pharmacology mechanisms. METHODS Male Sprague-Dawley rats were injected streptozotocin solution for 2 weeks, followed 6 weeks Rb1 or insulin treatment. The activity of SOD, CAT, Gpx, and the levels of MDA was measured; histological and ultrastructure analyses, RyR2 activity and phosphorylated RyR2(Ser2808) protein expression analyses; and Tunel assay were performed. RESULTS There was decreased activity of SOD, CAT, Gpx and increased levels of MDA in the diabetic group from control. Rb1 treatment increased activity of SOD, CAT, Gpx and decreased the levels of MDA as compared with diabetic rats. Neutralizing the RyR2 activity significantly decreased in diabetes from control, and increased in Rb1 treatment group from diabetic group. The expression of phosphorylation of RyR2 Ser2808 was increased in diabetic rats from control, and were attenuated with insulin and Rb1 treatment. Diabetes increased the apoptosis rate, and Rb1 treatment decreased the apoptosis rate. Rb1 and insulin ameliorated myocardial injury in diabetic rats. CONCLUSIONS These data indicate that Rb1 could be useful for mitigating oxidative damage, reduced phosphorylation of RyR2 Ser2808 and decreased the apoptosis rate of cardiomyocytes in diabetic cardiomyopathy.
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Affiliation(s)
- Chunpeng Feng
- Guang'anmen Hospital of China Academy of Chinese Medical Sciences, No 5. Beixiange Street, Beijing, 100053, China
| | - Jianping Song
- International Campus, Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, China
| | - Lan Deng
- Guang'anmen Hospital of China Academy of Chinese Medical Sciences, No 5. Beixiange Street, Beijing, 100053, China
| | - Jinfeng Zhang
- Jingmen Hospital of Traditional Chinese Medicine, Jingmen, China
| | - Xinyi Lian
- Guang'anmen Hospital of China Academy of Chinese Medical Sciences, No 5. Beixiange Street, Beijing, 100053, China
| | - Zhong Zhen
- Guang'anmen Hospital of China Academy of Chinese Medical Sciences, No 5. Beixiange Street, Beijing, 100053, China
| | - Jinfeng Liu
- Guang'anmen Hospital of China Academy of Chinese Medical Sciences, No 5. Beixiange Street, Beijing, 100053, China.
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2
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Okolo CA, Khaing EP, Mereacre V, Wallace RS, Munro ML, Erickson JR, Jones PP. Direct regulation of the cardiac ryanodine receptor (RyR2) by O-GlcNAcylation. Cardiovasc Diabetol 2023; 22:276. [PMID: 37833717 PMCID: PMC10576323 DOI: 10.1186/s12933-023-02010-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
BACKGROUND O-GlcNAcylation is the enzymatic addition of a sugar, O-linked β-N-Acetylglucosamine, to the serine and threonine residues of proteins, and is abundant in diabetic conditions. We have previously shown that O-GlcNAcylation can trigger arrhythmias by indirectly increasing pathological Ca2+ leak through the cardiac ryanodine receptor (RyR2) via Ca2+/calmodulin-dependent kinase II (CaMKII). However, RyR2 is well known to be directly regulated by other forms of serine and threonine modification, therefore, this study aimed to determine whether RyR2 is directly modified by O-GlcNAcylation and if this also alters the function of RyR2 and Ca2+ leak. METHODS O-GlcNAcylation of RyR2 in diabetic human and animal hearts was determined using western blotting. O-GlcNAcylation of RyR2 was pharmacologically controlled and the propensity for Ca2+ leak was determined using single cell imaging. The site of O-GlcNAcylation within RyR2 was determined using site-directed mutagenesis of RyR2. RESULTS We found that RyR2 is modified by O-GlcNAcylation in human, animal and HEK293 cell models. Under hyperglycaemic conditions O-GlcNAcylation was associated with an increase in Ca2+ leak through RyR2 which persisted after CaMKII inhibition. Conversion of serine-2808 to alanine prevented an O-GlcNAcylation induced increase in Ca2+ leak. CONCLUSIONS These data suggest that the function of RyR2 can be directly regulated by O-GlcNAcylation and requires the presence of serine-2808.
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Affiliation(s)
- Chidinma A Okolo
- Department of Physiology, School of Biomedical Sciences, Division of Health Sciences, and HeartOtago, University of Otago, Dunedin, Otago, New Zealand
- Beamline B24, Life Sciences Division, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, England, United Kingdom
| | - Ei-Phyo Khaing
- Department of Physiology, School of Biomedical Sciences, Division of Health Sciences, and HeartOtago, University of Otago, Dunedin, Otago, New Zealand
| | - Valeria Mereacre
- Department of Physiology, School of Biomedical Sciences, Division of Health Sciences, and HeartOtago, University of Otago, Dunedin, Otago, New Zealand
| | - Rachel S Wallace
- Department of Physiology, School of Biomedical Sciences, Division of Health Sciences, and HeartOtago, University of Otago, Dunedin, Otago, New Zealand
| | - Michelle L Munro
- Department of Physiology, School of Biomedical Sciences, Division of Health Sciences, and HeartOtago, University of Otago, Dunedin, Otago, New Zealand
| | - Jeffrey R Erickson
- Department of Physiology, School of Biomedical Sciences, Division of Health Sciences, and HeartOtago, University of Otago, Dunedin, Otago, New Zealand
| | - Peter P Jones
- Department of Physiology, School of Biomedical Sciences, Division of Health Sciences, and HeartOtago, University of Otago, Dunedin, Otago, New Zealand.
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3
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Clements RT, Terentyeva R, Hamilton S, Janssen PML, Roder K, Martin BY, Perger F, Schneider T, Nichtova Z, Das AS, Veress R, Lee BS, Kim DG, Koren G, Stratton MS, Csordas G, Accornero F, Belevych AE, Gyorke S, Terentyev D. Sexual dimorphism in bidirectional SR-mitochondria crosstalk in ventricular cardiomyocytes. Basic Res Cardiol 2023; 118:15. [PMID: 37138037 PMCID: PMC10156626 DOI: 10.1007/s00395-023-00988-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 05/05/2023]
Abstract
Calcium transfer into the mitochondrial matrix during sarcoplasmic reticulum (SR) Ca2+ release is essential to boost energy production in ventricular cardiomyocytes (VCMs) and match increased metabolic demand. Mitochondria from female hearts exhibit lower mito-[Ca2+] and produce less reactive oxygen species (ROS) compared to males, without change in respiration capacity. We hypothesized that in female VCMs, more efficient electron transport chain (ETC) organization into supercomplexes offsets the deficit in mito-Ca2+ accumulation, thereby reducing ROS production and stress-induced intracellular Ca2+ mishandling. Experiments using mitochondria-targeted biosensors confirmed lower mito-ROS and mito-[Ca2+] in female rat VCMs challenged with β-adrenergic agonist isoproterenol compared to males. Biochemical studies revealed decreased mitochondria Ca2+ uniporter expression and increased supercomplex assembly in rat and human female ventricular tissues vs male. Importantly, western blot analysis showed higher expression levels of COX7RP, an estrogen-dependent supercomplex assembly factor in female heart tissues vs males. Furthermore, COX7RP was decreased in hearts from aged and ovariectomized female rats. COX7RP overexpression in male VCMs increased mitochondrial supercomplexes, reduced mito-ROS and spontaneous SR Ca2+ release in response to ISO. Conversely, shRNA-mediated knockdown of COX7RP in female VCMs reduced supercomplexes and increased mito-ROS, promoting intracellular Ca2+ mishandling. Compared to males, mitochondria in female VCMs exhibit higher ETC subunit incorporation into supercomplexes, supporting more efficient electron transport. Such organization coupled to lower levels of mito-[Ca2+] limits mito-ROS under stress conditions and lowers propensity to pro-arrhythmic spontaneous SR Ca2+ release. We conclude that sexual dimorphism in mito-Ca2+ handling and ETC organization may contribute to cardioprotection in healthy premenopausal females.
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Affiliation(s)
- Richard T Clements
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island College of Pharmacy, Kingston, RI, USA
- Department of Medicine, Providence VAMC and Brown University, Providence, RI, USA
| | - Radmila Terentyeva
- Department of Physiology and Cell Biology, The Ohio State University, 460 Medical Center Dr, Columbus, OH, 43210, USA
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Shanna Hamilton
- Department of Physiology and Cell Biology, The Ohio State University, 460 Medical Center Dr, Columbus, OH, 43210, USA
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, The Ohio State University, 460 Medical Center Dr, Columbus, OH, 43210, USA
| | - Karim Roder
- Department of Medicine, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Benjamin Y Martin
- Department of Physiology and Cell Biology, The Ohio State University, 460 Medical Center Dr, Columbus, OH, 43210, USA
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Fruzsina Perger
- Department of Physiology and Cell Biology, The Ohio State University, 460 Medical Center Dr, Columbus, OH, 43210, USA
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Timothy Schneider
- Department of Pathology, Anatomy and Cell Biology, MitoCare Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Zuzana Nichtova
- Department of Pathology, Anatomy and Cell Biology, MitoCare Center, Thomas Jefferson University, Philadelphia, PA, USA
- Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Anindhya S Das
- Department of Physiology and Cell Biology, The Ohio State University, 460 Medical Center Dr, Columbus, OH, 43210, USA
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Roland Veress
- Department of Physiology and Cell Biology, The Ohio State University, 460 Medical Center Dr, Columbus, OH, 43210, USA
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Beth S Lee
- Department of Physiology and Cell Biology, The Ohio State University, 460 Medical Center Dr, Columbus, OH, 43210, USA
| | - Do-Gyoon Kim
- Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Gideon Koren
- Department of Medicine, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Matthew S Stratton
- Department of Physiology and Cell Biology, The Ohio State University, 460 Medical Center Dr, Columbus, OH, 43210, USA
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Gyorgy Csordas
- Department of Pathology, Anatomy and Cell Biology, MitoCare Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Federica Accornero
- Department of Physiology and Cell Biology, The Ohio State University, 460 Medical Center Dr, Columbus, OH, 43210, USA
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Andriy E Belevych
- Department of Physiology and Cell Biology, The Ohio State University, 460 Medical Center Dr, Columbus, OH, 43210, USA
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Sandor Gyorke
- Department of Physiology and Cell Biology, The Ohio State University, 460 Medical Center Dr, Columbus, OH, 43210, USA
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Dmitry Terentyev
- Department of Physiology and Cell Biology, The Ohio State University, 460 Medical Center Dr, Columbus, OH, 43210, USA.
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
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4
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Jaquenod De Giusti C, Palomeque J, Mattiazzi A. Ca 2+ mishandling and mitochondrial dysfunction: a converging road to prediabetic and diabetic cardiomyopathy. Pflugers Arch 2022; 474:33-61. [PMID: 34978597 PMCID: PMC8721633 DOI: 10.1007/s00424-021-02650-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 11/17/2021] [Accepted: 12/03/2021] [Indexed: 12/16/2022]
Abstract
Diabetic cardiomyopathy is defined as the myocardial dysfunction that suffers patients with diabetes mellitus (DM) in the absence of hypertension and structural heart diseases such as valvular or coronary artery dysfunctions. Since the impact of DM on cardiac function is rather silent and slow, early stages of diabetic cardiomyopathy, known as prediabetes, are poorly recognized, and, on many occasions, cardiac illness is diagnosed only after a severe degree of dysfunction was reached. Therefore, exploration and recognition of the initial pathophysiological mechanisms that lead to cardiac dysfunction in diabetic cardiomyopathy are of vital importance for an on-time diagnosis and treatment of the malady. Among the complex and intricate mechanisms involved in diabetic cardiomyopathy, Ca2+ mishandling and mitochondrial dysfunction have been described as pivotal early processes. In the present review, we will focus on these two processes and the molecular pathway that relates these two alterations to the earlier stages and the development of diabetic cardiomyopathy.
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Affiliation(s)
- Carolina Jaquenod De Giusti
- Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs. Médicas, UNLP, La Plata, Argentina
| | - Julieta Palomeque
- Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs. Médicas, UNLP, La Plata, Argentina
| | - Alicia Mattiazzi
- Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs. Médicas, UNLP, La Plata, Argentina.
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5
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Yang M, Yan J, Wu A, Zhao W, Qin J, Pogwizd SM, Wu X, Yuan S, Ai X. Alterations of housekeeping proteins in human aged and diseased hearts. Pflugers Arch 2021; 473:351-362. [PMID: 33638007 PMCID: PMC10468297 DOI: 10.1007/s00424-021-02538-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 01/20/2021] [Accepted: 02/04/2021] [Indexed: 01/10/2023]
Abstract
Pathological remodeling includes alterations of ion channel function and calcium homeostasis and ultimately cardiac maladaptive function during the process of disease development. Biochemical assays are important approaches for assessing protein abundance and post-translational modification of ion channels. Several housekeeping proteins are commonly used as internal controls to minimize loading variabilities in immunoblotting protein assays. Yet, emerging evidence suggests that some housekeeping proteins may be abnormally altered under certain pathological conditions. However, alterations of housekeeping proteins in aged and diseased human hearts remain unclear. In the current study, immunoblotting was applied to measure three commonly used housekeeping proteins (β-actin, calsequestrin, and GAPDH) in well-procured human right atria (RA) and left ventricles (LV) from diabetic, heart failure, and aged human organ donors. Linear regression analysis suggested that the amounts of linearly loaded total proteins and quantified intensity of total proteins from either Ponceau S (PS) blot-stained or Coomassie Blue (CB) gel-stained images were highly correlated. Thus, all immunoblotting data were normalized with quantitative CB or PS data to calibrate potential loading variabilities. In the human heart, β-actin was reduced in diabetic RA and LV, while GAPDH was altered in aged and diabetic RA but not LV. Calsequestrin, an important Ca2+ regulatory protein, was significantly changed in aged, diabetic, and ischemic failing hearts. Intriguingly, expression levels of all three proteins were unchanged in non-ischemic failing human LV. Overall, alterations of human housekeeping proteins are heart chamber specific and disease context dependent. The choice of immunoblotting loading controls should be carefully evaluated. Usage of CB or PS total protein analysis could be a viable alternative approach for some complicated pathological specimens.
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Affiliation(s)
- Mei Yang
- Department of Physiology and Biophysics, Rush University Medical Center, 1750 West Harrison St. 1255 Jelke South, Chicago, IL, 60612, USA
| | - Jiajie Yan
- Department of Physiology and Biophysics, Rush University Medical Center, 1750 West Harrison St. 1255 Jelke South, Chicago, IL, 60612, USA
| | - Aimee Wu
- Department of Physiology and Biophysics, Rush University Medical Center, 1750 West Harrison St. 1255 Jelke South, Chicago, IL, 60612, USA
| | - Weiwei Zhao
- Department of Physiology and Biophysics, Rush University Medical Center, 1750 West Harrison St. 1255 Jelke South, Chicago, IL, 60612, USA
| | - Jin Qin
- Department of Physiology and Biophysics, Rush University Medical Center, 1750 West Harrison St. 1255 Jelke South, Chicago, IL, 60612, USA
| | - Steven M Pogwizd
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Xin Wu
- Department of Physiology and Biophysics, Rush University Medical Center, 1750 West Harrison St. 1255 Jelke South, Chicago, IL, 60612, USA
| | - Shengtao Yuan
- Jiangsu Key Laboratory of Drug Screening, China Pharmaceutical University, No. 24, Tongjiaxiang, Nanjing, 210009, China.
| | - Xun Ai
- Department of Physiology and Biophysics, Rush University Medical Center, 1750 West Harrison St. 1255 Jelke South, Chicago, IL, 60612, USA.
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6
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Alomar FA, Al-Rubaish A, Al-Muhanna F, Al-Ali AK, McMillan J, Singh J, Bidasee KR. Adeno-Associated Viral Transfer of Glyoxalase-1 Blunts Carbonyl and Oxidative Stresses in Hearts of Type 1 Diabetic Rats. Antioxidants (Basel) 2020; 9:E592. [PMID: 32640624 PMCID: PMC7402150 DOI: 10.3390/antiox9070592] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 02/06/2023] Open
Abstract
Accumulation of methylglyoxal (MG) arising from downregulation of its primary degrading enzyme glyoxalase-1 (Glo1) is an underlying cause of diabetic cardiomyopathy (DC). This study investigated if expressing Glo1 in rat hearts shortly after the onset of Type 1 diabetes mellitus (T1DM) would blunt the development of DC employing the streptozotocin-induced T1DM rat model, an adeno-associated virus containing Glo1 driven by the endothelin-1 promoter (AAV2/9-Endo-Glo1), echocardiography, video edge, confocal imaging, and biochemical/histopathological assays. After eight weeks of T1DM, rats developed DC characterized by a decreased E:A ratio, fractional shortening, and ejection fraction, and increased isovolumetric relaxation time, E: e' ratio, and circumferential and longitudinal strains. Evoked Ca2+ transients and contractile kinetics were also impaired in ventricular myocytes. Hearts from eight weeks T1DM rats had lower Glo1 and GSH levels, elevated carbonyl/oxidative stress, microvascular leakage, inflammation, and fibrosis. A single injection of AAV2/9 Endo-Glo1 (1.7 × 1012 viron particles/kg) one week after onset of T1DM, potentiated GSH, and blunted MG accumulation, carbonyl/oxidative stress, microvascular leakage, inflammation, fibrosis, and impairments in cardiac and myocyte functions that develop after eight weeks of T1DM. These new data indicate that preventing Glo1 downregulation by administering AAV2/9-Endo-Glo1 to rats one week after the onset of T1DM, blunted the DC that develops after eight weeks of diabetes by attenuating carbonyl/oxidative stresses, microvascular leakage, inflammation, and fibrosis.
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Affiliation(s)
- Fadhel A. Alomar
- Department of Pharmacology and Toxicology, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia
| | - Abdullah Al-Rubaish
- Department of Internal Medicine, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia; (A.A.-R.); (F.A.-M.)
| | - Fahad Al-Muhanna
- Department of Internal Medicine, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia; (A.A.-R.); (F.A.-M.)
| | - Amein K. Al-Ali
- Institute for Research and Medical Consultation, Imam Abdulrahman bin Faisal University, Dammam 31441, Saudi Arabia;
| | - JoEllyn McMillan
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA;
- Environmental, Agricultural and Occupational Health, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA
| | - Jaipaul Singh
- College of Science and Technology, University of Central Lancashire, Preton PR1 2HE, England, UK;
| | - Keshore R. Bidasee
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA;
- Environmental, Agricultural and Occupational Health, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA
- Nebraska Redox Biology Center, Lincoln, NE 68588-0662, USA
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7
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Al Kury LT. Calcium Homeostasis in Ventricular Myocytes of Diabetic Cardiomyopathy. J Diabetes Res 2020; 2020:1942086. [PMID: 33274235 PMCID: PMC7683117 DOI: 10.1155/2020/1942086] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/24/2020] [Accepted: 10/29/2020] [Indexed: 12/12/2022] Open
Abstract
Diabetes mellitus (DM) is a chronic metabolic disorder commonly characterized by high blood glucose levels, resulting from defects in insulin production or insulin resistance, or both. DM is a leading cause of mortality and morbidity worldwide, with diabetic cardiomyopathy as one of its main complications. It is well established that cardiovascular complications are common in both types of diabetes. Electrical and mechanical problems, resulting in cardiac contractile dysfunction, are considered as the major complications present in diabetic hearts. Inevitably, disturbances in the mechanism(s) of Ca2+ signaling in diabetes have implications for cardiac myocyte contraction. Over the last decade, significant progress has been made in outlining the mechanisms responsible for the diminished cardiac contractile function in diabetes using different animal models of type I diabetes mellitus (TIDM) and type II diabetes mellitus (TIIDM). The aim of this review is to evaluate our current understanding of the disturbances of Ca2+ transport and the role of main cardiac proteins involved in Ca2+ homeostasis in the diabetic rat ventricular cardiomyocytes. Exploring the molecular mechanism(s) of altered Ca2+ signaling in diabetes will provide an insight for the identification of novel therapeutic approaches to improve the heart function in diabetic patients.
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Affiliation(s)
- Lina T. Al Kury
- Department of Health Sciences, College of Natural and Health Sciences, Zayed University, Abu Dhabi 144534, UAE
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8
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Hamilton S, Terentyev D. Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity. Front Physiol 2018. [PMID: 30425651 DOI: 10.3389/fphys.2018.01517, 10.3389/fpls.2018.01517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca2+ transport protein complexes including plasmalemmal L-type Ca2+ channels (LTCC), Na+-Ca2+ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca2+-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca2+ release channels. Here we provide an overview of changes in Ca2+ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca2+ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis.
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Affiliation(s)
- Shanna Hamilton
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
| | - Dmitry Terentyev
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
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9
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Hamilton S, Terentyev D. Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity. Front Physiol 2018; 9:1517. [PMID: 30425651 PMCID: PMC6218530 DOI: 10.3389/fphys.2018.01517] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/09/2018] [Indexed: 12/28/2022] Open
Abstract
A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca2+ transport protein complexes including plasmalemmal L-type Ca2+ channels (LTCC), Na+-Ca2+ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca2+-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca2+ release channels. Here we provide an overview of changes in Ca2+ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca2+ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis.
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Affiliation(s)
- Shanna Hamilton
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
| | - Dmitry Terentyev
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
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10
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Tse G, Yan BP, Chan YWF, Tian XY, Huang Y. Reactive Oxygen Species, Endoplasmic Reticulum Stress and Mitochondrial Dysfunction: The Link with Cardiac Arrhythmogenesis. Front Physiol 2016; 7:313. [PMID: 27536244 PMCID: PMC4971160 DOI: 10.3389/fphys.2016.00313] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/11/2016] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Cardiac arrhythmias represent a significant problem globally, leading to cerebrovascular accidents, myocardial infarction, and sudden cardiac death. There is increasing evidence to suggest that increased oxidative stress from reactive oxygen species (ROS), which is elevated in conditions such as diabetes and hypertension, can lead to arrhythmogenesis. METHOD A literature review was undertaken to screen for articles that investigated the effects of ROS on cardiac ion channel function, remodeling and arrhythmogenesis. RESULTS Prolonged endoplasmic reticulum stress is observed in heart failure, leading to increased production of ROS. Mitochondrial ROS, which is elevated in diabetes and hypertension, can stimulate its own production in a positive feedback loop, termed ROS-induced ROS release. Together with activation of mitochondrial inner membrane anion channels, it leads to mitochondrial depolarization. Abnormal function of these organelles can then activate downstream signaling pathways, ultimately culminating in altered function or expression of cardiac ion channels responsible for generating the cardiac action potential (AP). Vascular and cardiac endothelial cells become dysfunctional, leading to altered paracrine signaling to influence the electrophysiology of adjacent cardiomyocytes. All of these changes can in turn produce abnormalities in AP repolarization or conduction, thereby increasing likelihood of triggered activity and reentry. CONCLUSION ROS plays a significant role in producing arrhythmic substrate. Therapeutic strategies targeting upstream events include production of a strong reducing environment or the use of pharmacological agents that target organelle-specific proteins and ion channels. These may relieve oxidative stress and in turn prevent arrhythmic complications in patients with diabetes, hypertension, and heart failure.
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Affiliation(s)
- Gary Tse
- Li Ka Shing Faculty of Medicine, School of Biomedical Sciences, University of Hong KongHong Kong, China
- Department of Medicine and Therapeutics, Faculty of Medicine, Chinese University of Hong KongHong Kong, China
| | - Bryan P. Yan
- Department of Medicine and Therapeutics, Faculty of Medicine, Chinese University of Hong KongHong Kong, China
- Department of Epidemiology and Preventive Medicine, Monash UniversityMelbourne, VIC, Australia
| | - Yin W. F. Chan
- Department of Psychology, School of Biological Sciences, University of CambridgeCambridge, UK
| | - Xiao Yu Tian
- Faculty of Medicine, School of Biomedical Sciences, Chinese University of Hong KongHong Kong, China
| | - Yu Huang
- Faculty of Medicine, School of Biomedical Sciences, Chinese University of Hong KongHong Kong, China
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11
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Tse G, Lai ETH, Yeo JM, Yan BP. Electrophysiological Mechanisms of Bayés Syndrome: Insights from Clinical and Mouse Studies. Front Physiol 2016; 7:188. [PMID: 27303306 PMCID: PMC4886053 DOI: 10.3389/fphys.2016.00188] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/10/2016] [Indexed: 12/11/2022] Open
Abstract
Bayés syndrome is an under-recognized clinical condition characterized by inter-atrial block (IAB). This is defined electrocardiographically as P-wave duration > 120 ms and can be categorized into first, second and third degree IAB. It can be caused by inflammatory conditions such as systemic sclerosis and rheumatoid arthritis, abnormal protein deposition in cardiac amyloidosis, or neoplastic processes invading the inter-atrial conduction system, such as primary cardiac lymphoma. It may arise transiently during volume overload, autonomic dysfunction or electrolyte disturbances from vomiting. In other patients without an obvious cause, the predisposing factors are diabetes mellitus, hypertensive heart disease, and hypercholesterolemia. IAB has a strong association with atrial arrhythmogenesis, left atrial enlargement (LAE), and electro-mechanical discordance, increasing the risk of cerebrovascular accidents as well as myocardial and mesenteric ischemia. The aim of this review article is to synthesize experimental evidence on the pathogenesis of IAB and its underlying molecular mechanisms. Current medical therapies include anti-fibrotic, anti-arrhythmic and anti-coagulation agents, whereas interventional options include atrial resynchronization therapy by single or multisite pacing. Future studies will be needed to elucidate the significance of the link between IAB and atrial tachyarrhythmias in patients with different underlying etiologies and optimize the management options in these populations.
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Affiliation(s)
- Gary Tse
- Li Ka Shing Faculty of Medicine, School of Biomedical Sciences, University of Hong KongHong Kong, China
| | - Eric Tsz Him Lai
- Li Ka Shing Faculty of Medicine, School of Biomedical Sciences, University of Hong KongHong Kong, China
| | - Jie Ming Yeo
- School of Medicine, Imperial College LondonLondon, UK
| | - Bryan P. Yan
- Department of Medicine and Therapeutics, The Chinese University of Hong KongHong Kong, China
- Department of Epidemiology and Preventive Medicine, Monash UniversityMelbourne, VIC, Australia
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12
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Tse G, Lai ETH, Tse V, Yeo JM. Molecular and Electrophysiological Mechanisms Underlying Cardiac Arrhythmogenesis in Diabetes Mellitus. J Diabetes Res 2016; 2016:2848759. [PMID: 27642609 PMCID: PMC5011530 DOI: 10.1155/2016/2848759] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 04/28/2016] [Indexed: 01/11/2023] Open
Abstract
Diabetes is a common endocrine disorder with an ever increasing prevalence globally, placing significant burdens on our healthcare systems. It is associated with significant cardiovascular morbidities. One of the mechanisms by which it causes death is increasing the risk of cardiac arrhythmias. The aim of this article is to review the cardiac (ion channel abnormalities, electrophysiological and structural remodelling) and extracardiac factors (neural pathway remodelling) responsible for cardiac arrhythmogenesis in diabetes. It is concluded by an outline of molecular targets for future antiarrhythmic therapy for the diabetic population.
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Affiliation(s)
- Gary Tse
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong
- *Gary Tse:
| | - Eric Tsz Him Lai
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong
| | - Vivian Tse
- Department of Physiology, McGill University, Montreal, QC, Canada H3G 1Y6
| | - Jie Ming Yeo
- School of Medicine, Imperial College London, London SW7 2AZ, UK
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Bertinat R, Nualart F, Li X, Yáñez AJ, Gomis R. Preclinical and Clinical Studies for Sodium Tungstate: Application in Humans. ACTA ACUST UNITED AC 2015; 6. [PMID: 25995968 PMCID: PMC4435618 DOI: 10.4172/2155-9899.1000285] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Diabetes is a complex metabolic disorder triggered by the deficient secretion of insulin by the pancreatic β-cell or the resistance of peripheral tissues to the action of the hormone. Chronic hyperglycemia is the major consequence of this failure, and also the main cause of diabetic problems. Indeed, several clinical trials have agreed in that tight glycemic control is the best way to stop progression of the disease. Many anti-diabetic drugs for treatment of type 2 diabetes are commercially available, but no ideal normoglycemic agent has been developed yet. Moreover, weight gain is the most common side effect of many oral anti-diabetic agents and insulin, and increased weight has been shown to worsen glycemic control and increase the risk of diabetes progression. In this sense, the inorganic salt sodium tungstate (NaW) has been studied in different animal models of metabolic syndrome and diabetes, proving to have a potent effect on normalizing blood glucose levels and reducing body weight, without any hypoglycemic action. Although the liver has been studied as the main site of NaW action, positive effects have been also addressed in muscle, pancreas, brain, adipose tissue and intestine, explaining the effective anti-diabetic action of this salt. Here, we review NaW research to date in these different target organs. We believe that NaW deserves more attention, since all available anti-diabetic treatments remain suboptimal and new therapeutics are urgently needed.
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Affiliation(s)
- Romina Bertinat
- Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile ; Centro de Microscopía Avanzada, CMA-Bío Bío, Universidad de Concepción, Concepción, Chile
| | - Francisco Nualart
- Centro de Microscopía Avanzada, CMA-Bío Bío, Universidad de Concepción, Concepción, Chile
| | - Xuhang Li
- Division of Gastroenterology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Alejandro J Yáñez
- Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile ; Centro de Microscopía Avanzada, CMA-Bío Bío, Universidad de Concepción, Concepción, Chile
| | - Ramón Gomis
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain ; Diabetes and Obesity Research Laboratory, IDIBAPS, Barcelona, Spain ; Department of Endocrinology and Nutrition, Hospital Clinic, Barcelona, Spain ; Faculty of Medicine, University of Barcelona, Barcelona, Spain
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Tian C, Alomar F, Moore CJ, Shao CH, Kutty S, Singh J, Bidasee KR. Reactive carbonyl species and their roles in sarcoplasmic reticulum Ca2+ cycling defect in the diabetic heart. Heart Fail Rev 2014; 19:101-12. [PMID: 23430128 PMCID: PMC4732283 DOI: 10.1007/s10741-013-9384-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Efficient and rhythmic cardiac contractions depend critically on the adequate and synchronized release of Ca(2+) from the sarcoplasmic reticulum (SR) via ryanodine receptor Ca(2+) release channels (RyR2) and its reuptake via sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2a). It is well established that this orchestrated process becomes compromised in diabetes. What remain incompletely defined are the molecular mechanisms responsible for the dysregulation of RyR2 and SERCA2a in diabetes. Earlier, we found elevated levels of carbonyl adducts on RyR2 and SERCA2a isolated from hearts of type 1 diabetic rats and showed the presence of these posttranslational modifications compromised their functions. We also showed that these mono- and di-carbonyl reactive carbonyl species (RCS) do not indiscriminately react with all basic amino acid residues on RyR2 and SERCA2a; some residues are more susceptible to carbonylation (modification by RCS) than others. A key unresolved question in the field is which of the many RCS that are upregulated in the heart in diabetes chemically react with RyR2 and SERCA2a? This brief review introduces readers to the field of RCS and their roles in perturbing SR Ca(2+) cycling in diabetes. It also provides new experimental evidence that not all RCS that are upregulated in the heart in diabetes chemically react with RyR2 and SERCA2a, methylglyoxal and glyoxal preferentially do.
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Affiliation(s)
- Chengju Tian
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198
| | - Fadhel Alomar
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198
- Department of Pharmacology, University of Dammam, Kingdom of Saudi Arabia
| | - Caronda J Moore
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198
| | - Chun Hong Shao
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198
| | - Shelby Kutty
- Joint Division of Pediatric Cardiology, University of Nebraska/Creighton University and Children's Hospital and Medical Center, Omaha, Nebraska
| | - Jaipaul Singh
- School of Forensic and Investigative Sciences and School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, UK
| | - Keshore R. Bidasee
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198
- Department of Environmental, Agricultural and Occupational Health, University of Nebraska Medical Center, Omaha, NE 68198
- Nebraska Center for Redox Biology, N146 Beadle Center, Lincoln NE 68588-0662
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15
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Ozturk N, Olgar Y, Ozdemir S. Trace elements in diabetic cardiomyopathy: An electrophysiological overview. World J Diabetes 2013; 4:92-100. [PMID: 23961319 PMCID: PMC3746091 DOI: 10.4239/wjd.v4.i4.92] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 07/12/2013] [Accepted: 07/19/2013] [Indexed: 02/05/2023] Open
Abstract
There is a growing body of evidence that Diabetes Mellitus leads to a specific cardiomyopathy apart from vascular disease and bring about high morbidity and mortality throughout the world. Recent clinical and experimental studies have extensively demonstrated that this cardiomyopathy causes impaired cardiac performance manifested by early diastolic and late systolic dysfunction. This impaired cardiac performance most probably have emerged upon the expression and activity of regulatory proteins such as Na+/Ca2+ exchanger, sarcoplasmic reticulum Ca2+-ATPase, ryanodine receptor and phospholamban. Over years many therapeutic strategies have been recommended for treatment of diabetic cardiomyopathy. Lately, inorganic elements have been suggested to have anti-diabetic effects due to their suggested ability to regulate glucose homeostasis, reduce oxidative stress or suppress phosphatases. Recent findings have shown that trace elements exert many biological effects including insulin-mimetic or antioxidant activity and in this manner they have been recommended as potential candidates for treatment of diabetes-induced cardiac complications, an effect based on their modes of action. Some of these trace elements are known to play an essential role as component of enzymes and thus modulate the organ function in physiological and pathological conditions. Besides, they can also manipulate redox state of the channels via antioxidant properties and thus contribute to the regulation of [Ca2+]i homeostasis and cardiac ion channels. On account of little information about some trace elements, we discussed the effect of vanadium, selenium, zinc and tungstate on diabetic heart complications.
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16
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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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17
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Malondialdehyde and 4-hydroxynonenal adducts are not formed on cardiac ryanodine receptor (RyR2) and sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA2) in diabetes. Mol Cell Biochem 2013; 376:121-35. [PMID: 23354458 DOI: 10.1007/s11010-013-1558-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 01/09/2013] [Indexed: 12/31/2022]
Abstract
Recently, we reported an elevated level of glucose-generated carbonyl adducts on cardiac ryanodine receptor (RyR2) and sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2) in hearts of streptozotocin(STZ)-induced diabetic rats. We also showed these adduct impaired RyR2 and SERCA2 activities, and altered evoked Ca(2+) transients. What is less clear is if lipid-derived malondialdehyde (MDA) and 4-hydroxy-2-nonenal (4-HNE) also chemically react with and impair RyR2 and SERCA2 activities in diabetes? This study used western blot assays with adduct-specific antibodies and confocal microscopy to assess levels of MDA, 4-HNE, N (ε)-carboxy(methyl)lysine (CML), pentosidine, and pyrraline adducts on RyR2 and SERCA2 and evoked intracellular transient Ca(2+) kinetics in myocytes from control, diabetic, and treated-diabetic rats. MDA and 4-HNE adducts were not detected on RyR2 and SERCA2 from either control or 8 weeks diabetic rats with altered evoked Ca(2+) transients. However, CML, pentosidine, and pyrraline adducts were elevated three- to five-fold (p < 0.05). Treating diabetic rats with pyridoxamine (a scavenger of reactive carbonyl species, RCS) or aminoguanidine (a mixed reactive oxygen species-RCS scavenger) reduced CML, pentosidine, and pyrraline adducts on RyR2 and SERCA2 and blunted SR Ca(2+) cycling changes. Treating diabetic rats with the superoxide dismutase mimetic tempol had no impact on MDA and 4-HNE adducts on RyR2 and SERCA2, and on SR Ca(2+) cycling. From these data we conclude that lipid-derived MDA and 4-HNE adducts are not formed on RyR2 and SERCA2 in this model of diabetes, and are therefore unlikely to be directly contributing to the SR Ca(2+) dysregulation.
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Niggli E, Ullrich ND, Gutierrez D, Kyrychenko S, Poláková E, Shirokova N. Posttranslational modifications of cardiac ryanodine receptors: Ca(2+) signaling and EC-coupling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1833:866-75. [PMID: 22960642 DOI: 10.1016/j.bbamcr.2012.08.016] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 08/18/2012] [Accepted: 08/22/2012] [Indexed: 10/27/2022]
Abstract
In cardiac muscle, a number of posttranslational protein modifications can alter the function of the Ca(2+) release channel of the sarcoplasmic reticulum (SR), also known as the ryanodine receptor (RyR). During every heartbeat RyRs are activated by the Ca(2+)-induced Ca(2+) release mechanism and contribute a large fraction of the Ca(2+) required for contraction. Some of the posttranslational modifications of the RyR are known to affect its gating and Ca(2+) sensitivity. Presently, research in a number of laboratories is focused on RyR phosphorylation, both by PKA and CaMKII, or on RyR modifications caused by reactive oxygen and nitrogen species (ROS/RNS). Both classes of posttranslational modifications are thought to play important roles in the physiological regulation of channel activity, but are also known to provoke abnormal alterations during various diseases. Only recently it was realized that several types of posttranslational modifications are tightly connected and form synergistic (or antagonistic) feed-back loops resulting in additive and potentially detrimental downstream effects. This review summarizes recent findings on such posttranslational modifications, attempts to bridge molecular with cellular findings, and opens a perspective for future work trying to understand the ramifications of crosstalk in these multiple signaling pathways. Clarifying these complex interactions will be important in the development of novel therapeutic approaches, since this may form the foundation for the implementation of multi-pronged treatment regimes in the future. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Cardiac Pathways of Differentiation, Metabolism and Contraction.
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Affiliation(s)
- Ernst Niggli
- Department of Physiology, University of Bern, Bern, Switzerland.
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Aydemir M, Ozturk N, Dogan S, Aslan M, Olgar Y, Ozdemir S. Sodium tungstate administration ameliorated diabetes-induced electrical and contractile remodeling of rat heart without normalization of hyperglycemia. Biol Trace Elem Res 2012; 148:216-23. [PMID: 22351103 DOI: 10.1007/s12011-012-9350-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 01/26/2012] [Indexed: 01/01/2023]
Abstract
Recently, sodium tungstate was suggested to improve cardiac performance of diabetic rats in perfused hearts based on its insulinomimetic activity. In this study, we aimed to investigate the cellular and molecular mechanisms underlying this beneficial effect of sodium tungstate. Tungstate was administered (100 mg/kg/day) to diabetic and control rats intragastrically for 6 weeks. Blood glucose levels increased, whereas body weight, heart weight and plasma insulin levels decreased significantly in diabetic animals. Interestingly, none of these parameters was changed by tungstate treatment. On the other hand, fractional shortening and accompanying intracellular Ca(2+) [Ca(2+)](i) transients of isolated ventricular myocytes were measured, and sodium tungstate was found to improve the peak shortening and the amplitude of [Ca(2+)](i) transients in diabetic cardiomyocytes. Potassium and L-type Ca(2+) currents were also recorded in isolated ventricular cells. Significant restoration of suppressed I (to) and I (ss) was achieved by tungstate administration. Nevertheless, L-type calcium currents did not change either in untreated or treated diabetic rats. Tissue biochemical parameters including TBARS, protein carbonyl content, xanthine oxidase (XO) and xanthine dehydogenase (XDH) were also determined, and diabetes revealed a marked increase in TBARS and carbonyl content which were decreased significantly by tungstate treatment. Conversely, although XO and XDH activities didn't change in untreated diabetic rats, a remarkable but insignificant decrease was detected in treated animals. In conclusion, tungstate treatment improved diabetes-induced contractile abnormalities via restoration of dysregulated [Ca(2+)](i) and altered ionic currents. This beneficial effect is due to antioxidant property of sodium tungstate rather than normalization of hyperglycemia.
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Affiliation(s)
- Mustafa Aydemir
- Faculty of Medicine, Department of Biophysics, Akdeniz University, Antalya, Turkey
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Abstract
Metabolic syndrome is characterized by a combination of obesity, hypertension, insulin resistance, dyslipidemia, and impaired glucose tolerance. This multifaceted syndrome is often accompanied by a hyperdynamic circulatory state characterized by increased blood pressure, total blood volume, cardiac output, and metabolic tissue demand. Experimental, epidemiological, and clinical studies have demonstrated that patients with metabolic syndrome have significantly elevated cardiovascular morbidity and mortality rates. One of the main and frequent complications seen in metabolic syndrome is cardiovascular disease. The primary endpoints of cardiometabolic risk are coronary and peripheral arterial disease, myocardial infarction, congestive heart failure, arrhythmia, and stroke. Alterations in expression and/or functioning of several key proteins involved in regulating and maintaining ionic homeostasis can cause cardiac disturbances. One such group of proteins is known as ryanodine receptors (intracellular calcium release channels), which are the major channels through which Ca(2+) ions leave the sarcoplasmic reticulum, leading to cardiac muscle contraction. The economic cost of metabolic syndrome and its associated complications has a significant effect on health care budgets. Improvements in body weight, blood lipid profile, and hyperglycemia can reduce cardiometabolic risk. However, constant hyperadrenergic stimulation still contributes to the burden of disease. Normalization of the hyperdynamic circulatory state with conventional therapies is the most reasonable therapeutic strategy to date. JTV519 (K201) is a newly developed 1,4-benzothiazepine drug with antiarrhythmic and cardioprotective properties. It appears to be very effective in not only preventing but also in reversing the characteristic myocardial changes and preventing lethal arrhythmias. It is also a unique candidate to improve diastolic heart failure in metabolic syndrome.
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Affiliation(s)
- U Deniz Dincer
- Department of Pharmacology, Ufuk University School of Medicine. Mevlana Bulvari, Balgat, Ankara, Turkey
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Cantillo D, Sheibani H, Kappe CO. Flash flow pyrolysis: mimicking flash vacuum pyrolysis in a high-temperature/high-pressure liquid-phase microreactor environment. J Org Chem 2012; 77:2463-73. [PMID: 22321044 DOI: 10.1021/jo3001645] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Flash vacuum pyrolysis (FVP) is a gas-phase continuous-flow technique where a substrate is sublimed through a hot quartz tube under high vacuum at temperatures of 400-1100 °C. Thermal activation occurs mainly by molecule-wall collisions with contact times in the region of milliseconds. As a preparative method, FVP is used mainly to induce intramolecular high-temperature transformations leading to products that cannot easily be obtained by other methods. It is demonstrated herein that liquid-phase high-temperature/high-pressure (high-T/p) microreactor conditions (160-350 °C, 90-180 bar) employing near- or supercritical fluids as reaction media can mimic the results obtained using preparative gas-phase FVP protocols. The high-T/p liquid-phase "flash flow pyrolysis" (FFP) technique was applied to the thermolysis of Meldrum's acid derivatives, pyrrole-2,3-diones, and pyrrole-2-carboxylic esters, producing the expected target heterocycles in high yields with residence times between 10 s and 10 min. The exact control over flow rate (and thus residence time) using the liquid-phase FFP method allows a tuning of reaction selectivities not easily achievable using FVP. Since the solution-phase FFP method does not require the substrate to be volatile any more--a major limitation in classical FVP--the transformations become readily scalable, allowing higher productivities and space-time yields compared with gas-phase protocols. Differential scanning calorimetry measurements and extensive DFT calculations provided essential information on pyrolysis energy barriers and the involved reaction mechanisms. A correlation between computed activation energies and experimental gas-phase FVP (molecule-wall collisions) and liquid-phase FFP (molecule-molecule collisions) pyrolysis temperatures was derived.
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Affiliation(s)
- David Cantillo
- Christian Doppler Laboratory for Microwave Chemistry and Institute of Chemistry, Karl-Franzens-University Graz, Heinrichstrasse 28, A-8010 Graz, Austria
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Le Douairon Lahaye S, Gratas-Delamarche A, Malardé L, Zguira S, Vincent S, Lemoine Morel S, Carré F, Rannou Bekono F. Combined insulin treatment and intense exercise training improved basal cardiac function and Ca2+-cycling proteins expression in type 1 diabetic rats. Appl Physiol Nutr Metab 2012; 37:53-62. [DOI: 10.1139/h11-127] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study investigated the effects of 8 weeks of intense exercise training combined with insulin treatment on the Ca2+-cycling protein complex expression and their functional consequences on cardiac function in type 1 diabetic rat hearts. Diabetic Wistar rats were randomly assigned into the following groups: received no treatment, insulin-treated diabetic, trained diabetic, and trained insulin-treated diabetic. A control group was also included. Insulin treatment and (or) treadmill intense exercise training were conducted over 8 weeks. Basal cardiac function was evaluated by Langendorff technique. Cardiac expression of the main Ca2+-cycling proteins (RyR2, FKBP 12.6, SERCA2, PLB, NCX1) was assessed by Western blot. Diabetes altered basal cardiac function (±dP/dt) and decrease the expression of the main Ca2+-cycling proteins expression: RyR2, SERCA2, and NCX1 (p < 0.05). Whereas combined treatment was not able to normalize –dP/dt, it succeeded to normalize +dP/dt of diabetic rats (p < 0.05). Moreover, both insulin and intense exercise training, applied solely, increased the expression of the Ca2+-cycling proteins: RyR2, SERCA2, PLB. and NCX1 (p < 0.05). But this effect was higher when the 2 treatments were combined. These data are the first to show that combined insulin treatment and intense exercise training during diabetes synergistically act on the expression of the main Ca2+-cycling proteins, providing insights into mechanisms by which the dual treatment during diabetes improves cardiac function.
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Affiliation(s)
- Solène Le Douairon Lahaye
- Laboratory Movement and health Sciences, UFR APS, University of Rennes 2 Avenue Charles Tillon, 35044 Rennes cedex, France
| | - Arlette Gratas-Delamarche
- Laboratory Movement and health Sciences, UFR APS, University of Rennes 2 Avenue Charles Tillon, 35044 Rennes cedex, France
| | - Ludivine Malardé
- Laboratory Movement and health Sciences, UFR APS, University of Rennes 2 Avenue Charles Tillon, 35044 Rennes cedex, France
| | - Sami Zguira
- Laboratory Movement and health Sciences, UFR APS, University of Rennes 2 Avenue Charles Tillon, 35044 Rennes cedex, France
| | - Sophie Vincent
- Laboratory Movement and health Sciences, UFR APS, University of Rennes 2 Avenue Charles Tillon, 35044 Rennes cedex, France
| | - Sophie Lemoine Morel
- Laboratory Movement and health Sciences, UFR APS, University of Rennes 2 Avenue Charles Tillon, 35044 Rennes cedex, France
| | - François Carré
- INSERM, U642; University of Rennes 1, LTSI; INSERM – CIC-IT 804; CHU Rennes, Department of Biology and Sports Medicine service of functional explorations, Rennes, France
| | - Françoise Rannou Bekono
- Laboratory Movement and health Sciences, UFR APS, University of Rennes 2 Avenue Charles Tillon, 35044 Rennes cedex, France
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Cardioprotective effect of propranolol on diabetes-induced altered intracellular Ca2+ signaling in rat. J Bioenerg Biomembr 2011; 43:747-56. [DOI: 10.1007/s10863-011-9400-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Accepted: 10/12/2011] [Indexed: 10/15/2022]
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Lee TI, Chen YC, Kao YH, Hsiao FC, Lin YK, Chen YJ. Rosiglitazone induces arrhythmogenesis in diabetic hypertensive rats with calcium handling alteration. Int J Cardiol 2011; 165:299-307. [PMID: 21917327 DOI: 10.1016/j.ijcard.2011.08.072] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 08/20/2011] [Indexed: 01/06/2023]
Abstract
BACKGROUND Diabetes and hypertension have significant effects on cardiac calcium (Ca(2+)) regulation, which plays an essential role in determining cardiac function. The effect of peroxisome proliferator-activated receptor (PPAR)-γ agonists on Ca(2+) regulation in the cardiomyocytes is unclear. OBJECTIVE The purpose of this study was to investigate the effects of hypertension, diabetes, and PPAR-γ agonist-rosiglitazone on the regulation of Ca(2+) and the electrophysiological characteristics of isolated ventricular myocytes. METHODS The indo-1 fluorometric ratio technique and whole-cell patch clamp were used to investigate intracellular Ca(2+) (Ca(2+)i), action potentials, and ionic currents in ventricular myocytes from rats of Wistar-Kyoto (WKY), diabetic WKY (induced by streptozotocin), diabetic WKY treated with rosiglitazone (5mg/kg), spontaneously hypertensive rats (SHR), diabetic SHR, and diabetic SHR treated with rosiglitazone. Western blot was used to evaluate protein expressions of sarcoplasmic reticulum ATPase (SERCA2a), Na(+)-Ca(2+) exchanger (NCX), and ryanodine receptor (RyR). RESULTS Diabetic WKY and diabetic SHR had smaller sarcoplasmic reticulum Ca(2+) contents, and Ca(2+)i transients with a prolonged decay portion, down-regulated SERCA2a, NCX, and RyR protein expressions and smaller L-type Ca(2+) currents than non-diabetic WKY and SHR, respectively. The Ca(2+) dysregulations in diabetes were attenuated in rats treated with rosiglitazone. Diabetes and hypertension both prolonged the action potential duration which were enhanced by the use of rosiglitazone, and induced the genesis of triggered activity. CONCLUSIONS Diabetes and hypertension modulate Ca(2+) handling. Rosiglitazone significantly changed the Ca(2+) regulation and electrophysiological characteristics, and may contain an arrhythmogenic potential in diabetes with hypertension.
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Affiliation(s)
- Ting-I Lee
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
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25
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Mekahli D, Bultynck G, Parys JB, De Smedt H, Missiaen L. Endoplasmic-reticulum calcium depletion and disease. Cold Spring Harb Perspect Biol 2011; 3:a004317. [PMID: 21441595 PMCID: PMC3098671 DOI: 10.1101/cshperspect.a004317] [Citation(s) in RCA: 329] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The endoplasmic reticulum (ER) as an intracellular Ca(2+) store not only sets up cytosolic Ca(2+) signals, but, among other functions, also assembles and folds newly synthesized proteins. Alterations in ER homeostasis, including severe Ca(2+) depletion, are an upstream event in the pathophysiology of many diseases. On the one hand, insufficient release of activator Ca(2+) may no longer sustain essential cell functions. On the other hand, loss of luminal Ca(2+) causes ER stress and activates an unfolded protein response, which, depending on the duration and severity of the stress, can reestablish normal ER function or lead to cell death. We will review these various diseases by mainly focusing on the mechanisms that cause ER Ca(2+) depletion.
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Affiliation(s)
- Djalila Mekahli
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, KU Leuven Campus Gasthuisberg O&N I, Belgium
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26
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Tian C, Shao CH, Moore CJ, Kutty S, Walseth T, DeSouza C, Bidasee KR. Gain of function of cardiac ryanodine receptor in a rat model of type 1 diabetes. Cardiovasc Res 2011; 91:300-9. [PMID: 21421556 DOI: 10.1093/cvr/cvr076] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
AIMS Ventricular myocytes isolated from hearts of streptozotocin (STZ)-diabetic rats exhibit increased spontaneous Ca(2+) release. Studies attribute this defect to an enhancement in activity of type 2 ryanodine receptor (RyR2). To date, underlying reasons for RyR2 dysregulation remain undefined. This study assesses whether the responsiveness of RyR2 following stimulation by intrinsic ligands is being altered during experimental type 1 diabetes (T1D). METHODS AND RESULTS M-mode echocardiography established a cardiomyopathy in 8 weeks STZ-diabetic rats. Confocal microscopy confirmed an increase in the spontaneous Ca(2+) release in isolated ventricular myocytes. Western blots revealed no significant change in steady-state levels of the RyR2 protein. When purified to homogeneity and incorporated into planar lipid bilayers, RyR2 from STZ-diabetic rats (dRyR2) exhibited reduced current amplitude at ±35 mV. dRyR2 was also more responsive to intrinsic cytoplasmic activators Ca(2+), adenosine triphosphate, and cyclic adenosine diphosphate ribose and less responsive to the cytoplasmic deactivator Mg(2+). Threshold for the activation of RyR2 by trans (luminal) Ca(2+) was also reduced. These changes were independent of phosphorylation at Ser2808 and Ser2814. Two weeks of insulin treatment starting after 6 weeks of diabetes blunted the phenotype change, indicating that the gain of function is specific to the diabetes and not the result of STZ interacting directly with RyR2. CONCLUSION These data show, for the first time, that RyR2 is acquiring a gain-of-function phenotype independent of its phosphorylation status during T1D and provides new insights for the enhanced spontaneous Ca(2+) release in myocytes from T1D rats.
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Affiliation(s)
- Chengju Tian
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA
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27
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Diabetes-related defects in sarcoplasmic Ca2+ release are prevented by inactivation of G(alpha)11 and G(alpha)q in murine cardiomyocytes. Mol Cell Biochem 2010; 341:235-44. [PMID: 20372981 DOI: 10.1007/s11010-010-0454-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2009] [Accepted: 03/25/2010] [Indexed: 10/19/2022]
Abstract
Neurohumoral stimulation of Gq-coupled receptors has been proposed as a central mechanism in the pathogenesis of diabetic heart disease. The resulting contractile dysfunction is closely related to abnormal intracellular Ca(2+) handling with functional defects of the sarcoplasmic reticulum (SR). The present study was therefore designed to determine the role of G(q)-protein signaling via G(alpha)(11) and G(alpha)(q) in diabetes for the induction of functional and structural changes in the Ca(2+) release complex of the SR. An experimental type 1-diabetes was induced in wild type, G(alpha)(11) knockout, and G(alpha)(11/q)-knockout mice by injection of streptozotocin. Cardiac morphology and function was assessed in vivo by echocardiography. SR Ca(2+) leak was tested in vitro based on a (45)Ca(2+) assay and protein densities as well as gene expression of ryanodine receptor (RyR2), FKBP12.6, sorcin, and annexin A7 were analyzed by immunoblot and RT-PCR. In wild type animals 8 weeks of diabetes resulted in cardiac hypertrophy and SR Ca(2+) leak was increased. In addition, diabetic wild type animals showed reduced protein levels of FKBP12.6 and annexin A7. In G(alpha)(11)- and G(alpha)(11/q)-knockout animals, however, SR Ca(2+) release and cardiac phenotype remained unchanged upon induction of diabetes. Densities of the proteins that we presently analyzed were also unaltered in G(alpha)(11)-knockout mice. G(alpha)(11/q)-knockout animals even showed increased expression of sorcin and annexin A7. Thus, based on the present study we suggest a signaling pathway via the G(q)-proteins, G(alpha)(11) and G(alpha)(q), that could link increased neurohumoral stimulation in diabetes with defective RyR2 channel function by regulating protein expression of FKBP12.6, annexin A7, and sorcin.
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Tatsunami R, Oba T, Takahashi K, Tampo Y. Methylglyoxal causes dysfunction of thioredoxin and thioredoxin reductase in endothelial cells. J Pharmacol Sci 2009; 111:426-32. [PMID: 19966511 DOI: 10.1254/jphs.09131fp] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Methylglyoxal (MG), a reactive dicarbonyl produced during glucose metabolism, induces oxidative stress and apoptosis. Under hyperglycemic conditions, the abnormal accumulation of MG is related to the development of diabetic complications. We examined the effects of MG on thioredoxin (Trx) and glutaredoxin (Grx) systems, two thiol-disulfide oxidoreductase systems that protect against oxidative damage of proteins, in bovine aortic endothelial cells (BAECs). The levels of protein carbonyls as markers of protein oxidation increased in BAECs exposed to MG at 5 mM, resulting in the loss of cell viability. Western blot analysis demonstrated that Trx protein level decreased when BAECs were exposed to 5 mM MG. MG also inactivated Trx reductase, which maintains Trx in the reduced/active state. Moreover, peroxiredoxin, which is dependent on Trx and Trx reductase to maintain its reduced state, was oxidized by 5 mM MG. No significant difference in the levels of Trx, Trx reductase, or peroxiredoxin was observed in BAECs exposed to MG at 1 mM; this concentration had little effect on protein carbonyl formation and cell viability. MG failed to decrease Grx activity, indicating that Trx is more susceptible to MG than Grx. Taken together, these findings suggest that MG causes dysfunction of the Trx system, including Trx and Trx reductase, in BAECs.
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Affiliation(s)
- Ryosuke Tatsunami
- Hokkaido Pharmaceutical University School of Pharmacy, Hokkaido 047-0264, Japan
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30
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Shao CH, Wehrens XHT, Wyatt TA, Parbhu S, Rozanski GJ, Patel KP, Bidasee KR. Exercise training during diabetes attenuates cardiac ryanodine receptor dysregulation. J Appl Physiol (1985) 2009; 106:1280-92. [PMID: 19131475 DOI: 10.1152/japplphysiol.91280.2008] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The present study was undertaken to assess the effects of exercise training (ExT) initiated after the onset of diabetes on cardiac ryanodine receptor expression and function. Type 1 diabetes was induced in male Sprague-Dawley rats using streptozotocin (STZ). Three weeks after STZ injection, diabetic rats were divided into two groups. One group underwent ExT for 4 wk while the other group remained sedentary. After 7 wk of sedentary diabetes, cardiac fractional shortening, rate of rise of left ventricular pressure, and myocyte contractile velocity were reduced by 14, 36, 44%, respectively. Spontaneous Ca(2+) spark frequency increased threefold, and evoked Ca(2+) release was dyssynchronous with diastolic Ca(2+) releases. Steady-state type 2 ryanodine receptor (RyR2) protein did not change, but its response to Ca(2+) was altered. RyR2 also exhibited 1.8- and 1.5-fold increases in phosphorylation at Ser(2808) and Ser(2814). PKA activity was reduced by 75%, but CaMKII activity was increased by 50%. Four weeks of ExT initiated 3 wk after the onset of diabetes blunted decreases in cardiac fractional shortening and rate of left ventricular pressure development, increased the responsiveness of the myocardium to isoproterenol stimulation, attenuated the increase in Ca(2+) spark frequency, and minimized dyssynchronous and diastolic Ca(2+) releases. ExT also normalized the responsiveness of RyR2 to Ca(2+) activation, attenuated increases in RyR2 phosphorylation at Ser(2808) and Ser(2814), and normalized CaMKII and PKA activities. These data are the first to show that ExT during diabetes normalizes RyR2 function and Ca(2+) release from the sarcoplasmic reticulum, providing insights into mechanisms by which ExT during diabetes improves cardiac function.
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Affiliation(s)
- Chun-Hong Shao
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
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31
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Sharov VS, Schöneich C. Chapter 6 Oxidative Modification of Ca2+ Channels, Ryanodine Receptors, and the Sarco/Endoplasmic Reticulum Ca2+-ATPase. CURRENT TOPICS IN MEMBRANES 2008. [DOI: 10.1016/s1063-5823(08)00206-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Durham WJ, Wehrens XHT, Sood S, Hamilton SL. Diseases associated with altered ryanodine receptor activity. Subcell Biochem 2007; 45:273-321. [PMID: 18193641 DOI: 10.1007/978-1-4020-6191-2_10] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Mutations in two intracellular Ca2+ release channels or ryanodine receptors (RyR1 and RyR2) are associated with a number of human skeletal and cardiac diseases. This chapter discusses these diseases in terms of known mechanisms, controversies, and unanswered questions. We also compare the cardiac and skeletal muscle diseases to explore common mechanisms.
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Affiliation(s)
- W J Durham
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
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33
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Li S, Li X, Li YL, Shao CH, Bidasee KR, Rozanski GJ. Insulin regulation of glutathione and contractile phenotype in diabetic rat ventricular myocytes. Am J Physiol Heart Circ Physiol 2006; 292:H1619-29. [PMID: 17056675 DOI: 10.1152/ajpheart.00140.2006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cardiovascular complications of diabetes mellitus involve oxidative stress and profound changes in reduced glutathione (GSH), an essential tripeptide that controls many redox-sensitive cell functions. This study examined regulation of GSH by insulin to identify mechanisms controlling cardiac redox state and to define the functional impact of GSH depletion. GSH was measured by fluorescence microscopy in ventricular myocytes isolated from Sprague-Dawley rats made diabetic by streptozotocin, and video and confocal microscopy were used to measure mechanical properties and Ca(2+) transients, respectively. Spectrophotometric assays of tissue extracts were also done to measure the activities of enzymes that control GSH levels. Four weeks after injection of streptozotocin, mean GSH concentration ([GSH]) in isolated diabetic rat myocytes was approximately 36% less than in control, correlating with decreased activities of two major enzymes regulating GSH levels: glutathione reductase and gamma-glutamylcysteine synthetase. Treatment of diabetic rat myocytes with insulin normalized [GSH] after a delay of 3-4 h. A more rapid but transient upregulation of [GSH] occurred in myocytes treated with dichloroacetate, an activator of pyruvate dehydrogenase. Inhibitor experiments indicated that insulin normalized [GSH] via the pentose pathway and gamma-glutamylcysteine synthetase, although the basal activity of glucose-6-phosphate dehydrogenase was not different between diabetic and control hearts. Diabetic rat myocytes were characterized by significant mechanical dysfunction that correlated with diminished and prolonged Ca(2+) transients. This phenotype was reversed by in vitro treatment with insulin and also by exogenous GSH or N-acetylcysteine, a precursor of GSH. Our data suggest that insulin regulates GSH through pathways involving de novo GSH synthesis and reduction of its oxidized form. It is proposed that a key function of glucose metabolism in heart is to supply reducing equivalents required to maintain adequate GSH levels for the redox control of Ca(2+) handling proteins and contraction.
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Affiliation(s)
- Shumin Li
- Dept of Cellular and Integrative Physiology, Univ of Nebraska College of Medicine, 985850 Nebraska Medical Center, Omaha, NE 68198-5850, USA
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Shao CH, Rozanski GJ, Patel KP, Bidasee KR. Dyssynchronous (non-uniform) Ca2+ release in myocytes from streptozotocin-induced diabetic rats. J Mol Cell Cardiol 2006; 42:234-46. [PMID: 17027851 DOI: 10.1016/j.yjmcc.2006.08.018] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Revised: 08/03/2006] [Accepted: 08/28/2006] [Indexed: 12/21/2022]
Abstract
Using biochemical/pharmacological approaches, we previously showed that type 2 ryanodine receptors (RyR2) become dysfunctional in hearts of streptozotocin-induced type 1 diabetic rats. However, the functional consequence of this observation remains incompletely understood. Here we use laser confocal microscopy to investigate whether RyR2 dysfunction during diabetes alters evoked and spontaneous Ca(2+) release from the sarcoplasmic reticulum (SR). After 7-8 weeks of diabetes, steady-state levels of RyR2 remain unchanged in hearts of male Sprague-Dawley rats, but the number of functional receptors decreased by >37%. Interestingly, residual functional RyR2 from diabetic rat hearts exhibited increased sensitivity to Ca(2+) activation (EC(50activation) decreased from 80 microM to 40 microM, peak Ca(2+) activation decreased from 425 microM to 160 microM). When field stimulated, intracellular Ca(2+) release in diabetic ventricular myocytes was dyssynchronous (non-uniform) and this was independent of L-type Ca(2+) currents. Time to peak Ca(2+) increased 3.7-fold. Diabetic myocytes also exhibited diastolic Ca(2+) release and 2-fold higher frequency of spontaneous Ca(2+) sparks, albeit at a lower amplitude. The amplitude of caffeine-releasable Ca(2+) was also lower in diabetic myocytes. RyR2 from diabetic rat hearts exhibited increased phosphorylation at Ser2809 and contained reduced levels of FKBP12.6 (calstablin2). Collectively, these data suggest that RyR2 becomes leaky during diabetes and this defect may be responsible to the reduced SR Ca(2+) load. Diastolic Ca(2+) release could also serve as a substrate for delayed after-depolarizations, contributing to the increased incidence of arrhythmias and sudden cardiac death in type 1 diabetes.
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Affiliation(s)
- Chun-Hong Shao
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA
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35
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Yaras N, Bilginoglu A, Vassort G, Turan B. Restoration of diabetes-induced abnormal local Ca2+ release in cardiomyocytes by angiotensin II receptor blockade. Am J Physiol Heart Circ Physiol 2006; 292:H912-20. [PMID: 17012347 DOI: 10.1152/ajpheart.00824.2006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Stimulation of local renin-angiotensin system and increased levels of oxidants characterize the diabetic heart. Downregulation of ANG II type 1 receptors (AT(1)) and enhancement in PKC activity in the heart point out the role of AT(1) blockers in diabetes. The purpose of this study was to evaluate a potential role of an AT(1) blocker, candesartan, on abnormal Ca(2+) release mechanisms and its relationship with PKC in the cardiomyocytes from streptozotocin-induced diabetic rats. Cardiomyocytes were isolated enzymatically and then incubated with either candesartan or a nonspecific PKC inhibitor bisindolylmaleimide I (BIM) for 6-8 h at 37 degrees C. Both candesartan and BIM applied on diabetic cardiomyocytes significantly restored the altered kinetic parameters of Ca(2+) transients, as well as depressed Ca(2+) loading of sarcoplasmic reticulum, basal Ca(2+) level, and spatiotemporal properties of the Ca(2+) sparks. In addition, candesartan and BIM significantly antagonized the hyperphosphorylation of cardiac ryanodine receptor (RyR2) and restored the depleted protein levels of both RyR2 and FK506 binding protein 12.6 (FKBP12.6). Furthermore, candesartan and BIM also reduced the increased PKC levels and oxidized protein thiol level in membrane fraction of diabetic rat cardiomyocytes. Taken together, these data demonstrate that AT(1) receptor blockade protects cardiomyocytes from development of cellular alterations typically associated with Ca(2+) release mechanisms in diabetes mellitus. Prevention of these alterations by candesartan may present a useful pharmacological strategy for the treatment of diabetic cardiomyopathy.
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Affiliation(s)
- Nazmi Yaras
- Department of Biophysics, School of Medicine, Ankara University, Sihhiye, 06100, Ankara, Turkey
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Yaras N, Ugur M, Ozdemir S, Gurdal H, Purali N, Lacampagne A, Vassort G, Turan B. Effects of diabetes on ryanodine receptor Ca release channel (RyR2) and Ca2+ homeostasis in rat heart. Diabetes 2005; 54:3082-8. [PMID: 16249429 DOI: 10.2337/diabetes.54.11.3082] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The defects identified in the mechanical activity of the hearts from type 1 diabetic animals include alteration of Ca2+ signaling via changes in critical processes that regulate intracellular Ca2+ concentration. These defects result partially from a dysfunction of cardiac ryanodine receptor calcium release channel (RyR2). The present study was designed to determine whether the properties of the Ca2+ sparks might provide insight into the role of RyR2 in the altered Ca2+ signaling in cardiomyocytes from diabetic animals when they were analyzed together with Ca2+ transients. Basal Ca2+ level as well as Ca2+-spark frequency of cardiomyoctes isolated from 5-week streptozotocin (STZ)-induced diabetic rats significantly increased with respect to aged-matched control rats. Ca2+ transients exhibited significantly reduced amplitude and prolonged time courses as well as depressed Ca2+ loading of sarcoplasmic reticulum in diabetic rats. Spatio-temporal properties of the Ca2+ sparks in cardiomyocytes isolated from diabetic rats were also significantly altered to being almost parallel to the changes of Ca2+ transients. In addition, RyR2 from diabetic rat hearts were hyperphosphorylated and protein levels of both RyR2 and FKBP12.6 depleted. These data show that STZ-induced diabetic rat hearts exhibit altered local Ca2+ signaling with increased basal Ca2+ level.
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Affiliation(s)
- Nazmi Yaras
- Department of Biophysics, School of Medicine, Ankara University, Ankara, Turkey
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Abstract
Oxidative stress and the resulting change in cell redox state are proposed to contribute to pathogenic alterations in ion channels that underlie electrical remodeling of the diseased heart. The present study examined whether K(+) channel remodeling is controlled by endogenous oxidoreductase systems that regulate redox-sensitive cell functions. Diabetes was induced in rats by streptozotocin, and experiments were conducted after 3-5 wk of hyperglycemia. Spectrophotometric assays of ventricular tissue extracts from diabetic rat hearts revealed divergent changes in two major oxidoreductase systems. The thioredoxin (TRX) system in diabetic rat heart was characterized by a 52% decrease in TRX reductase (TRXR) activity from control heart (P < 0.05), whereas TRX activity was 1.7-fold greater than control heart (P < 0.05). Diabetes elicited similar changes in the glutaredoxin (GRX) system: glutathione reductase was decreased 35% from control level (P < 0.05), and GRX activity was 2.5-fold greater than in control heart (P < 0.05). The basal activity of glucose-6-phosphate dehydrogenase, which generates NADPH required by the TRX and GRX systems, was not altered by diabetes. Voltage-clamp studies showed that the characteristically decreased density of the transient outward K(+) current (I(to)) in isolated diabetic rat myocytes was normalized by in vitro treatment with insulin (0.1 microM) or the metabolic activator dichloroacetate (1.5 mM). The effect of these agonists on I(to) was blocked by inhibitors of glucose-6-phosphate dehydrogenase. Moreover, inhibitors of TRXR, which controls the reducing activity of TRX, also blocked upregulation of I(to) by insulin and dichloroacetate. These data suggest that K(+) channels underlying I(to) are regulated in a redox-sensitive manner by the TRX system and the remodeling of I(to) that occurs in diabetes may be due to decreased TRXR activity. We propose that oxidoreductase systems are an important repair mechanism that protects ion channels and associated regulatory proteins from irreversible oxidative damage.
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Affiliation(s)
- Xun Li
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, USA
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Bidasee KR, Zhang Y, Shao CH, Wang M, Patel KP, Dincer UD, Besch HR. Diabetes increases formation of advanced glycation end products on Sarco(endo)plasmic reticulum Ca2+-ATPase. Diabetes 2004; 53:463-73. [PMID: 14747299 DOI: 10.2337/diabetes.53.2.463] [Citation(s) in RCA: 174] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Prolongation of relaxation is a hallmark of diabetic cardiomyopathy. Most studies attribute this defect to decreases in sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2a) expression and SERCA2a-to-phospholamban (PLB) ratio. Since its turnover rate is slow, SERCA2a is susceptible to posttranslational modifications during diabetes. These modifications could in turn compromise conformational rearrangements needed to translocate calcium ions, also leading to a decrease in SERCA2a activity. In the present study one such modification was investigated, namely advanced glycation end products (AGEs). Hearts from 8-week streptozotocin-induced diabetic (8D) rats showed typical slowing in relaxation, confirming cardiomyopathy. Hearts from 8D animals also expressed lower levels of SERCA2a protein and higher levels of PLB. Analysis of matrix-assisted laser desorption/ionization time-of-flight mass data files from trypsin-digested SERCA2a revealed several cytosolic SERCA2a peptides from 8D modified by single noncrosslinking AGEs. Crosslinked AGEs were also found. Lysine residues within actuator and phosphorylation domains were cross-linked to arginine residues within the nucleotide binding domain via pentosidine AGEs. Two weeks of insulin-treatment initiated after 6 weeks of diabetes attenuated these changes. These data demonstrate for the first time that AGEs are formed on SERCA2a during diabetes, suggesting a novel mechanism by which cardiac relaxation can be slowed during diabetes.
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MESH Headings
- Animals
- Calcium-Transporting ATPases/genetics
- Calcium-Transporting ATPases/metabolism
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/enzymology
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/physiopathology
- Glycation End Products, Advanced/metabolism
- Heart/physiopathology
- Insulin/therapeutic use
- Isoproterenol/pharmacology
- Male
- RNA, Messenger/genetics
- Rats
- Rats, Sprague-Dawley
- Sarcoplasmic Reticulum/enzymology
- Sarcoplasmic Reticulum Calcium-Transporting ATPases
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Function, Left/drug effects
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Affiliation(s)
- Keshore R Bidasee
- Department of Pharmacology, University of Nebraska Medical Center, Omaha, Nebraska, USA.
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