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Dewanjee S, Vallamkondu J, Kalra RS, John A, Reddy PH, Kandimalla R. Autophagy in the diabetic heart: A potential pharmacotherapeutic target in diabetic cardiomyopathy. Ageing Res Rev 2021; 68:101338. [PMID: 33838320 DOI: 10.1016/j.arr.2021.101338] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/24/2021] [Accepted: 03/29/2021] [Indexed: 12/20/2022]
Abstract
Association of diabetes with an elevated risk of cardiac failure has been clinically evident. Diabetes potentiates diastolic and systolic cardiac failure following the myocardial infarction that produces the cardiac muscle-specific microvascular complication, clinically termed as diabetic cardiomyopathy. Elevated susceptibility of diabetic cardiomyopathy is primarily caused by the generation of free radicals in the hyperglycemic milieu, compromising the myocardial contractility and normal cardiac functions with increasing redox insult, impaired mitochondria, damaged organelles, apoptosis, and cardiomyocytes fibrosis. Autophagy is essentially involved in the recycling/clearing the damaged organelles, cytoplasmic contents, and aggregates, which are frequently produced in cardiomyocytes. Although autophagy plays a vital role in maintaining the cellular homeostasis in diligent cardiac tissues, this process is frequently impaired in the diabetic heart. Given its clinical significance, accumulating evidence largely showed the functional aspects of autophagy in diabetic cardiomyopathy, elucidating its intricate protective and pathogenic outcomes. However, etiology and molecular readouts of these contrary autophagy activities in diabetic cardiomyopathy are not yet comprehensively assessed and translated. In this review, we attempted to assess the role of autophagy and its adaptations in the diabetic heart. To delineate the molecular consequences of these events, we provided detailed insights into the autophagy regulation pieces of machinery including the mTOR/AMPK, TFEB/ZNSCAN3, FOXOs, SIRTs, PINK1/Parkin, Nrf2, miRNAs, and others in the diabetic cardiomyopathy. Given the clinical significance of autophagy in the diabetic heart, we further discussed the potential pharmacotherapeutic strategies towards targeting autophagy. Taken together, the present report meticulously assessed autophagy, its adaptations, and molecular regulations in diabetic cardiomyopathy and reviewed the current autophagy-targeting strategies.
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Affiliation(s)
- Saikat Dewanjee
- Advanced Pharmacognosy Research Laboratory, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, 700032, India.
| | | | - Rajkumar Singh Kalra
- AIST-INDIA DAILAB, National Institute of Advanced Industrial Science & Technology (AIST), Higashi 1-1-1, Tsukuba, 305 8565, Japan.
| | - Albin John
- Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - P Hemachandra Reddy
- Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Neuroscience & Pharmacology, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Neurology, Departments of School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Public Health Department of Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Department of Speech, Language and Hearing Sciences, School Health Professions, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
| | - Ramesh Kandimalla
- Department of Biochemistry, Kakatiya Medical College, Warangal, 506007, Telangana, India; Applied Biology, CSIR-Indian Institute of Technology, Uppal Road, Tarnaka, Hyderabad, 50000, Telangana, India.
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Mishra S, Dunkerly-Eyring BL, Keceli G, Ranek MJ. Phosphorylation Modifications Regulating Cardiac Protein Quality Control Mechanisms. Front Physiol 2020; 11:593585. [PMID: 33281625 PMCID: PMC7689282 DOI: 10.3389/fphys.2020.593585] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 09/28/2020] [Indexed: 12/12/2022] Open
Abstract
Many forms of cardiac disease, including heart failure, present with inadequate protein quality control (PQC). Pathological conditions often involve impaired removal of terminally misfolded proteins. This results in the formation of large protein aggregates, which further reduce cellular viability and cardiac function. Cardiomyocytes have an intricately collaborative PQC system to minimize cellular proteotoxicity. Increased expression of chaperones or enhanced clearance of misfolded proteins either by the proteasome or lysosome has been demonstrated to attenuate disease pathogenesis, whereas reduced PQC exacerbates pathogenesis. Recent studies have revealed that phosphorylation of key proteins has a potent regulatory role, both promoting and hindering the PQC machinery. This review highlights the recent advances in phosphorylations regulating PQC, the impact in cardiac pathology, and the therapeutic opportunities presented by harnessing these modifications.
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Affiliation(s)
- Sumita Mishra
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Brittany L Dunkerly-Eyring
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University, Baltimore, MD, United States
| | - Gizem Keceli
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Mark J Ranek
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
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Guan Y, Zhou L, Zhang Y, Tian H, Li A, Han X. Effects of PP2A/Nrf2 on experimental diabetes mellitus-related cardiomyopathy by regulation of autophagy and apoptosis through ROS dependent pathway. Cell Signal 2019; 62:109339. [PMID: 31173878 DOI: 10.1016/j.cellsig.2019.06.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 06/02/2019] [Accepted: 06/04/2019] [Indexed: 01/08/2023]
Abstract
Diabetes mellitus-related cardiomyopathy (DMCMP) has been defined as ventricular dysfunction that occurs in diabetic patients independent of a recognized cause such as coronary artery disease or hypertension. Mechanisms underlying DMCMP have not been fully elucidated. In this study, the roles of protein phosphatase 2A/nuclear factor NF-E2-related factor 2 (PP2A/Nrf2) in experimental DMCMP induced by high glucose were studied in vitro and in vivo. The results showed that high glucose could induce experimental DMCMP and increase ROS generation, increase the expression and nuclear translocation of Nrf2, down-regulate the expression of PI3K/Akt/mTOR and up-regulate the expression of ERK, and activate the autophagy of cardiomyocytes. The activity or expression of PP2A in DMCMP increased. PP2A could up-regulate the expression of Nrf2 and promote cardiomyocytes autophagy and apoptosis. Inhibition of PP2A could reduce the expression of Nrf2 and inhibit the autophagy and apoptosis of cardiomyocytes. The results suggested that hyperglycemic-induced experimental DMCMP may be related to up-regulating the expression of Nrf2 through PP2A/Nrf2 pathway. These results will be helpful to elucidate the pathogenesis and mechanism of DMCMP and find targets for the development of new drugs to prevent or treat DMCMP.
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Affiliation(s)
- Yanhui Guan
- Department of Pharmacology, School of Pharmaceutical Sciences, Shandong University, 44 West Wenhua Road, Jinan 250012, China
| | - Lichun Zhou
- Department of Pharmacology, School of Pharmaceutical Sciences, Shandong University, 44 West Wenhua Road, Jinan 250012, China
| | - Yu Zhang
- Department of Pharmacology, School of Pharmaceutical Sciences, Shandong University, 44 West Wenhua Road, Jinan 250012, China
| | - Huiqin Tian
- Department of Pharmacology, School of Pharmaceutical Sciences, Shandong University, 44 West Wenhua Road, Jinan 250012, China; Department of Pharmacology, Shandong college of Traditional Chinese Medicine, 508 East Binhai road, Yantai 264199, China
| | - Anqi Li
- Department of Pharmacology, School of Pharmaceutical Sciences, Shandong University, 44 West Wenhua Road, Jinan 250012, China
| | - Xiuzhen Han
- Department of Pharmacology, School of Pharmaceutical Sciences, Shandong University, 44 West Wenhua Road, Jinan 250012, China; Key Laboratory of Chemical Biology of Natural Products, Ministry of Education, Shandong University, Jinan, China.
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Liu YY, Sun C, Xue FS, Yang GZ, Li HX, Liu Q, Liao X. Effect of Autophagy Inhibition on the Protection of Ischemia Preconditioning against Myocardial Ischemia/Reperfusion Injury in Diabetic Rats. Chin Med J (Engl) 2018; 131:1702-1709. [PMID: 29998890 PMCID: PMC6048915 DOI: 10.4103/0366-6999.235867] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Ischemia preconditioning (IPC) remains the most powerful intervention of protection against myocardial ischemia/reperfusion injury (IRI), but diabetes can weaken or eliminate its cardioprotective effect and detailed mechanisms remain unclear. In this study, we aimed to explore whether changes of autophagy in the diabetic condition are attributable to the decreased cardioprotective effect of IPC. METHODS Sixty diabetic male Sprague-Dawley rats were randomly divided into the control (C), IRI, rapamycin (R), wortmannin (W), rapamycin + IPC (R + IPC), and wortmannin + IPC (W + IPC) groups. The in vivo rat model of myocardial IRI was established by ligaturing and opening the left anterior descending coronary artery via the left thoracotomy. Durations of ischemia and reperfusion are 30 min and 120 min, respectively. Blood samples were taken at 120 min of reperfusion for measuring serum concentrations of troponin I (TnI) and creatine kinase isoenzyme MB (CK-MB) using the enzyme-linked immunosorbent assay. The infarct size was assessed by Evans blue and triphenyltetrazolium chloride staining. The expressions of LC3-II, beclin-1, phosphoinositide 3-kinase (PI3K), mammalian target of rapamycin (mTOR), and P-Akt/Akt ratio in the ischemic myocardium were assessed by Western blotting. RESULTS Compared to the IRI group, infarct size (56.1% ± 6.1% vs. 75.4 ± 7.1%, P < 0.05), serum cTnI (0.61 ± 0.21 vs. 0.95 ± 0.26 ng/ml, P < 0.05), and CK-MB levels (6.70 ± 1.25 vs. 11.51 ± 2.35 ng/ml, P < 0.05) obviously decreased in the W + IPC group. Compared with the C group, myocardial expressions of LC3-II (0.46 ± 0.04 and 0.56 ± 0.04 vs. 0.36 ± 0.04, P < 0.05) and beclin-1 (0.34 ± 0.08 and 0.38 ± 0.07 vs. 0.24 ± 0.03, P < 0.05) evidently increased, and myocardial expressions of mTOR (0.26 ± 0.08 and 0.25 ± 0.07 vs. 0.38 ± 0.06, P < 0.05), PI3K (0.29 ± 0.04 and 0.30 ± 0.03 vs. 0.38 ± 0.02, P < 0.05), and P-Akt/Akt ratio (0.49 ± 0.10 and 0.48 ± 0.06 vs. 0.72 ± 0.07, P < 0.05) markedly decreased in the IRI and R groups, indicating an increased autophagy. Compared with the IRI group, myocardial expression of beclin-1 (0.26 ± 0.03 vs. 0.34 ± 0.08, P < 0.05) significantly decreased, and myocardial expressions of mTOR (0.36 ± 0.04 vs. 0.26 ± 0.08, P < 0.05), PI3K (0.37 ± 0.03 vs. 0.29 ± 0.04, P < 0.05), and P-Akt/Akt ratio (0.68 ± 0.05 vs. 0.49 ± 0.10, P < 0.05) increased obviously in the W + IPC group, indicating a decreased autophagy. CONCLUSIONS Increased autophagy in the diabetic myocardium is attributable to decreased cardioprotection of IPC, and autophagy inhibited by activating the PI3K-Akt-mTOR signaling pathway can result in an improved protection of IPC against diabetic myocardial IRI.
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Affiliation(s)
- Ya-Yang Liu
- Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100041, China
| | - Chao Sun
- Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100041, China
| | - Fu-Shan Xue
- Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100041, China
| | - Gui-Zhen Yang
- Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100041, China
| | - Hui-Xian Li
- Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100041, China
| | - Qing Liu
- Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100041, China
| | - Xu Liao
- Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100041, China
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Delbridge LMD, Benson VL, Ritchie RH, Mellor KM. Diabetic Cardiomyopathy: The Case for a Role of Fructose in Disease Etiology. Diabetes 2016; 65:3521-3528. [PMID: 27879401 DOI: 10.2337/db16-0682] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 09/09/2016] [Indexed: 11/13/2022]
Abstract
A link between excess dietary sugar and cardiac disease is clearly evident and has been largely attributed to systemic metabolic dysregulation. Now a new paradigm is emerging, and a compelling case can be made that fructose-associated heart injury may be attributed to the direct actions of fructose on cardiomyocytes. Plasma and cardiac fructose levels are elevated in patients with diabetes, and evidence suggests that some unique properties of fructose (vs. glucose) have specific cardiomyocyte consequences. Investigations to date have demonstrated that cardiomyocytes have the capacity to transport and utilize fructose and express all of the necessary proteins for fructose metabolism. When dietary fructose intake is elevated and myocardial glucose uptake compromised by insulin resistance, increased cardiomyocyte fructose flux represents a hazard involving unregulated glycolysis and oxidative stress. The high reactivity of fructose supports the contention that fructose accelerates subcellular hexose sugar-related protein modifications, such as O-GlcNAcylation and advanced glycation end product formation. Exciting recent discoveries link heart failure to induction of the specific high-affinity fructose-metabolizing enzyme, fructokinase, in an experimental setting. In this Perspective, we review key recent findings to synthesize a novel view of fructose as a cardiopathogenic agent in diabetes and to identify important knowledge gaps for urgent research focus.
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Affiliation(s)
- Lea M D Delbridge
- Department of Physiology, University of Melbourne, Victoria, Australia
| | - Vicky L Benson
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Rebecca H Ritchie
- Heart Failure Pharmacology, Baker IDI Heart and Diabetes Institute, Victoria, Australia
| | - Kimberley M Mellor
- Department of Physiology, University of Melbourne, Victoria, Australia
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
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Mellor KM, Brimble MA, Delbridge LM. Glucose as an agent of post-translational modification in diabetes — New cardiac epigenetic insights. Life Sci 2015; 129:48-53. [DOI: 10.1016/j.lfs.2014.03.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 03/11/2014] [Accepted: 03/17/2014] [Indexed: 01/07/2023]
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Yao H, Han X, Han X. The cardioprotection of the insulin-mediated PI3K/Akt/mTOR signaling pathway. Am J Cardiovasc Drugs 2014; 14:433-42. [PMID: 25160498 DOI: 10.1007/s40256-014-0089-9] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Apoptosis occurs frequently in myocardial infarction, oxidative stress injury, and ischemia/reperfusion injury, and plays a pivotal role in the development of heart diseases. Inhibition of apoptosis alone does not necessarily lead to meaningful rescue in terms of either cardiomyocyte survival or function. Activation of the PI3K/Akt signaling pathway induced by insulin not only inhibits cardiomyocyte apoptosis but also substantially preserves and even improves regional and overall cardiac function. Insulin can protect cardiomyocytes from apoptosis by regulating a number of signaling molecules, such as eNOS, FOXOs, Bad, GSK-3β, mTOR, NDRG2, and Nrf2, through activating PI3K and Akt. This review focuses on the protective mechanisms and targets of insulin identified in the prevention and treatment of myocardial injury.
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Liu J, Tang Y, Feng Z, Hou C, Wang H, Yan J, Liu J, Shen W, Zang W, Liu J, Long J. Acetylated FoxO1 mediates high-glucose induced autophagy in H9c2 cardiomyoblasts: regulation by a polyphenol -(-)-epigallocatechin-3-gallate. Metabolism 2014; 63:1314-23. [PMID: 25062567 DOI: 10.1016/j.metabol.2014.06.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 06/14/2014] [Accepted: 06/16/2014] [Indexed: 11/18/2022]
Abstract
OBJECTIVE FoxO1 acts as a pivotal transcription factor in insulin signaling. However, in hyperglycemia induced cardiac complications, whether FoxO1 is involved remains unclear. The goal of this study was to delineate the potential role of FoxO1 under high-glucose condition. MATERIALS/METHODS We investigated insulin resistance and reactive oxygen species (ROS) generation in H9c2 cardiomyoblasts after high-glucose exposure. A series of autophagy biomarkers were measured and further confirmed by LC3 turnover assay. Using gene silencing and overexpression experiments we dissected the molecular mechanisms of FoxO1 regulated autophagy. We also tested the protective effect of (-)-epigallocatechin-3-gallate (EGCG, a green tea-derived polyphenol) in high-glucose treated H9c2 cardiomyoblasts. RESULTS High-glucose elicited elevated ROS, autophagy and FoxO1 abundance in cultured H9c2 cardiomyoblasts. Specifically, high-glucose significantly augmented the acetylated FoxO1 in cytosol. In line, compared with 3A-FoxO1 (majorly localized in nuclei with a strong transcriptional activity), overexpression of WT-FoxO1 led to more intense elevated autophagy with enhanced acetylation of FoxO1. In addition, FoxO1 RNAi brought down autophagy induced by high-glucose. Intriguingly, EGCG successfully reversed ROS, autophagy and acetylated FoxO1 in high-glucose treated H9c2 cells. CONCLUSION Our findings suggest that FoxO1, especially the acetylated form, regulates high-glucose induced autophagy in H9c2 cardiomyoblasts, which can be prevented by EGCG via a possible ROS-FoxO1 pathway.
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Affiliation(s)
- Jia Liu
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Life Science, FIST, Xi'an Jiaotong University, Xi'an 710049, China
| | - Ying Tang
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Life Science, FIST, Xi'an Jiaotong University, Xi'an 710049, China
| | - Zhihui Feng
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Life Science, FIST, Xi'an Jiaotong University, Xi'an 710049, China
| | - Chen Hou
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Life Science, FIST, Xi'an Jiaotong University, Xi'an 710049, China
| | - Hui Wang
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Life Science, FIST, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jiong Yan
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Life Science, FIST, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jing Liu
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Life Science, FIST, Xi'an Jiaotong University, Xi'an 710049, China
| | - Weili Shen
- Shanghai Institute of Hypertension, Ruijin Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Weijin Zang
- Department of Pharmacology, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Jiankang Liu
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Life Science, FIST, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Jiangang Long
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Life Science, FIST, Xi'an Jiaotong University, Xi'an 710049, China.
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Ouyang C, You J, Xie Z. The interplay between autophagy and apoptosis in the diabetic heart. J Mol Cell Cardiol 2013; 71:71-80. [PMID: 24513079 DOI: 10.1016/j.yjmcc.2013.10.014] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 10/07/2013] [Accepted: 10/21/2013] [Indexed: 11/19/2022]
Abstract
Diabetic cardiomyopathy is characterized by ventricular dysfunction that occurs in diabetic patients independent of coronary artery disease, hypertension, and any other cardiovascular diseases. Diabetic cardiomyopathy has become a major cause of diabetes-related mortality. Thus, an urgent need exists to clarify the mechanism of pathogenesis. Emerging evidence demonstrates that diabetes induces cardiomyocyte apoptosis and suppresses cardiac autophagy, indicating that the interplay between the autophagy and apoptotic cell death pathways is important in the pathogenesis of diabetic cardiomyopathy. This review highlights recent advances in the crosstalk between autophagy and apoptosis and its importance in the development of diabetic cardiomyopathy. This article is part of a Special Issue entitled "Protein Quality Control, the Ubiquitin Proteasome System, and Autophagy".
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Affiliation(s)
- Changhan Ouyang
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Jieyun You
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Zhonglin Xie
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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Myocardial glycophagy - a specific glycogen handling response to metabolic stress is accentuated in the female heart. J Mol Cell Cardiol 2013; 65:67-75. [PMID: 24080183 DOI: 10.1016/j.yjmcc.2013.09.014] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Revised: 09/19/2013] [Accepted: 09/21/2013] [Indexed: 01/03/2023]
Abstract
Cardiac metabolic stress is a hallmark of many cardiac pathologies, including diabetes. Cardiac glycogen mis-handling is a frequent manifestation of various cardiopathologies. Diabetic females have a higher risk of heart disease than males, yet sex disparities in cardiac metabolic stress settings are not well understood. Oestrogen acts on key glycogen regulatory proteins. The goal of this study was to evaluate sex-specific metabolic stress-triggered cardiac glycogen handling responses. Male and female adult C57Bl/6J mice were fasted for 48h. Cardiac glycogen content, particle size, regulatory enzymes, signalling intermediates and autophagic processes were evaluated. Female hearts exhibited 51% lower basal glycogen content than males associated with lower AMP-activated-kinase (AMPK) activity (35% decrease in pAMPK:AMPK). With fasting, glycogen accumulated in female hearts linked with decreased particle size and upregulation of Akt and AMPK signalling, activation of glycogen synthase and inactivation of glycogen phosphorylase. Fasting did not alter glycogen content or regulatory proteins in male hearts. Expression of glycogen autophagy marker, starch-binding-protein-domain-1 (STBD1), was 63% lower in female hearts than males and increased by 69% with fasting in females only. Macro-autophagy markers, p62 and LC3BII:I ratio, increased with fasting in male and female hearts. This study identifies glycogen autophagy ('glycophagy') as a potentially important component of the response to cardiac metabolic stress. Glycogen autophagy occurs in association with a marked and selective accumulation of glycogen in the female myocardium. Our findings suggest that sex-specific differences in glycogen handling may have cardiopathologic consequences in various settings, including diabetic cardiomyopathy.
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