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Daniels LJ, Varma U, Annandale M, Chan E, Mellor KM, Delbridge LMD. Myocardial Energy Stress, Autophagy Induction, and Cardiomyocyte Functional Responses. Antioxid Redox Signal 2019; 31:472-486. [PMID: 30417655 DOI: 10.1089/ars.2018.7650] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Significance: Energy stress in the myocardium occurs in a variety of acute and chronic pathophysiological contexts, including ischemia, nutrient deprivation, and diabetic disease settings of substrate disturbance. Although the heart is highly adaptive and flexible in relation to fuel utilization and routes of adenosine-5'-triphosphate (ATP) generation, maladaptations in energy stress situations confer functional deficit. An understanding of the mechanisms that link energy stress to impaired myocardial performance is crucial. Recent Advances: Emerging evidence suggests that, in parallel with regulated enzymatic pathways that control intracellular substrate supply, other processes of "bulk" autophagic macromolecular breakdown may be important in energy stress conditions. Recent findings indicate that cargo-specific autophagic activity may be important in different stress states. In particular, induction of glycophagy, a glycogen-specific autophagy, has been described in acute and chronic energy stress situations. The impact of elevated cardiomyocyte glucose flux relating to glycophagy dysregulation on contractile function is unknown. Critical Issues: Ischemia- and diabetes-related cardiac adverse events comprise the majority of cardiovascular disease morbidity and mortality. Current therapies involve management of systemic comorbidities. Cardiac-specific adjunct treatments targeted to manage myocardial energy stress responses are lacking. Future Directions: New knowledge is required to understand the mechanisms involved in selective recruitment of autophagic responses in the cardiomyocyte energy stress response. In particular, exploration of the links between cell substrate flux, calcium ion (Ca2+) flux, and phagosomal cargo flux is required. Strategies to target specific fuel "bulk" management defects in cardiac energy stress states may be of therapeutic value.
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Affiliation(s)
- Lorna J Daniels
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Upasna Varma
- 2 Department of Physiology, University of Melbourne, Melbourne, Australia
| | - Marco Annandale
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Eleia Chan
- 2 Department of Physiology, University of Melbourne, Melbourne, Australia
| | - Kimberley M Mellor
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand.,2 Department of Physiology, University of Melbourne, Melbourne, Australia.,3 Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Lea M D Delbridge
- 2 Department of Physiology, University of Melbourne, Melbourne, Australia
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Feidantsis K, Mellidis K, Galatou E, Sinakos Z, Lazou A. Treatment with crocin improves cardiac dysfunction by normalizing autophagy and inhibiting apoptosis in STZ-induced diabetic cardiomyopathy. Nutr Metab Cardiovasc Dis 2018; 28:952-961. [PMID: 30017436 DOI: 10.1016/j.numecd.2018.06.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 06/05/2018] [Accepted: 06/07/2018] [Indexed: 10/28/2022]
Abstract
BACKGROUND AND AIM The association of diabetes mellitus (DM) and poor metabolic control with high incidence of cardiovascular diseases is well established. The aim of this study was to investigate the potential cardioprotective effect of crocin (Crocus sativus L. extract) on diabetic heart dysfunction and to elucidate the mediating molecular mechanisms. METHODS AND RESULTS Streptozotocin (STZ)-induced diabetic rats were treated with two different concentrations of crocin (10 or 20 mg/kg), while isolated cardiac myocytes exposed to 25 mM glucose, were treated with 1 or 10 μM of crocin. Treatment of STZ-diabetic rats with crocin resulted in normalization of plasma glucose levels, inhibition of cardiac hypertrophy and fibrosis, and improvement of cardiac contractile function. Heat Shock Response was enhanced. Myocardial AMPK phosphorylation was increased after treatment with crocin, resulting in normalization of autophagy marker proteins (LC3BII/LC3BI ratio, SQSTM1/p62 and Beclin-1), while the diabetes-induced myocardial apoptosis was decreased. Similar results regarding the effect of crocin on autophagy and apoptosis pathways were obtained in isolated cardiac myocytes exposed to high concentration of glucose. CONCLUSION The results suggest that crocin improves the deteriorated cardiac function in diabetic animals by enhancing the heat shock response, inhibiting apoptosis and normalizing autophagy in cardiac myocytes. Thus, treatment with crocin may represent a novel approach for treating diabetic cardiomyopathy.
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Affiliation(s)
- K Feidantsis
- Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, 54124, Greece
| | - K Mellidis
- Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, 54124, Greece
| | - E Galatou
- Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, 54124, Greece
| | - Z Sinakos
- Emeritus Professor of Hematology, Aristotle University of Thessaloniki, Thessaloniki, 54124, Greece
| | - A Lazou
- Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, 54124, Greece.
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Wang F, Jia J, Rodrigues B. Autophagy, Metabolic Disease, and Pathogenesis of Heart Dysfunction. Can J Cardiol 2017; 33:850-859. [PMID: 28389131 DOI: 10.1016/j.cjca.2017.01.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/29/2016] [Accepted: 01/04/2017] [Indexed: 12/12/2022] Open
Abstract
In normal physiology, autophagy is recognized as a protective housekeeping mechanism that enables elimination of unhealthy organelles, protein aggregates, and invading pathogens, as well as recycling cell components and producing new building blocks and energy for cellular renovation and homeostasis. However, overactive or depressed autophagy is often associated with the pathogenesis of multiple disorders, including cardiac disease. During metabolic disorders, such as diabetes and obesity, dysregulation of autophagy frequently leads to cell death, cardiomyopathy, and cardiac dysfunction. In this article, we summarize the current understanding of autophagy-its classification, progression, and regulation; its roles in both physiological and pathophysiological conditions; and the balance between autophagy and apoptosis. We also explore how dysregulation of autophagy leads to cell death in models of metabolic disease and its contributing factors-including nutrient state, hyperglycemia, dyslipidemia, insulin inefficiency, and oxidative stress-and outline some recent efforts to restore normal autophagy in pathophysiological states. This information could provide potential targets for the prevention of, or intervention in, cardiac failure in metabolic disorders such as diabetes and obesity.
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Affiliation(s)
- Fulong Wang
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Jocelyn Jia
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian Rodrigues
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada.
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Mei Y, Glover K, Su M, Sinha SC. Conformational flexibility of BECN1: Essential to its key role in autophagy and beyond. Protein Sci 2016; 25:1767-85. [PMID: 27414988 DOI: 10.1002/pro.2984] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/09/2016] [Accepted: 07/12/2016] [Indexed: 01/16/2023]
Abstract
BECN1 (Beclin 1), a highly conserved eukaryotic protein, is a key regulator of autophagy, a cellular homeostasis pathway, and also participates in vacuolar protein sorting, endocytic trafficking, and apoptosis. BECN1 is important for embryonic development, the innate immune response, tumor suppression, and protection against neurodegenerative disorders, diabetes, and heart disease. BECN1 mediates autophagy as a core component of the class III phosphatidylinositol 3-kinase complexes. However, the exact mechanism by which it regulates the activity of these complexes, or mediates its other diverse functions is unclear. BECN1 interacts with several diverse protein partners, perhaps serving as a scaffold or interaction hub for autophagy. Based on extensive structural, biophysical and bioinformatics analyses, BECN1 consists of an intrinsically disordered region (IDR), which includes a BH3 homology domain (BH3D); a flexible helical domain (FHD); a coiled-coil domain (CCD); and a β-α-repeated autophagy-specific domain (BARAD). Each of these BECN1 domains mediates multiple diverse interactions that involve concomitant conformational changes. Thus, BECN1 conformational flexibility likely plays a key role in facilitating diverse protein interactions. Further, BECN1 conformation and interactions are also modulated by numerous post-translational modifications. A better structure-based understanding of the interplay between different BECN1 conformational and binding states, and the impact of post-translational modifications will be essential to elucidating the mechanism of its multiple biological roles.
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Affiliation(s)
- Yang Mei
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota, 58108-6050
| | - Karen Glover
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota, 58108-6050
| | - Minfei Su
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota, 58108-6050
| | - Sangita C Sinha
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota, 58108-6050.
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Munasinghe PE, Riu F, Dixit P, Edamatsu M, Saxena P, Hamer NSJ, Galvin IF, Bunton RW, Lequeux S, Jones G, Lamberts RR, Emanueli C, Madeddu P, Katare R. Type-2 diabetes increases autophagy in the human heart through promotion of Beclin-1 mediated pathway. Int J Cardiol 2015; 202:13-20. [PMID: 26386349 DOI: 10.1016/j.ijcard.2015.08.111] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 08/06/2015] [Accepted: 08/07/2015] [Indexed: 12/22/2022]
Abstract
BACKGROUND Diabetes promotes progressive loss of cardiac cells, which are replaced by a fibrotic matrix, resulting in the loss of cardiac function. In the current study we sought to identify if excessive autophagy plays a major role in inducing this progressive loss. METHODS AND RESULTS Immunofluorescence and western blotting analysis of the right atrial appendages collected from diabetic and non-diabetic patients undergoing coronary artery bypass graft surgery showed a marked increase in the level of autophagy in the diabetic heart, as evidenced by increased expression of autophagy marker LC3B-II and its mediator Beclin-1 and decreased expression of p62, which incorporates into autophagosomes to be efficiently degraded. Moreover, a marked activation of pro-apoptotic caspase-3 was observed. Electron microscopy showed increased autophagosomes in the diabetic heart. In vivo measurement of autophagic flux by choloroquine injection resulted in further enhancement of LC3B-II in the diabetic myocardium, confirming increased autophagic activity in the type-2 diabetic heart. Importantly, in-vitro genetic depletion of beclin-1 in high glucose treated adult rat cardiomyocytes markedly inhibited the level of autophagy and subsequent apoptotic cell death. CONCLUSIONS These findings demonstrate the pathological role of autophagy in the type-2 diabetic heart, opening up a potentially novel therapeutic avenue for the treatment of diabetic heart disease.
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MESH Headings
- Animals
- Apoptosis/genetics
- Apoptosis Regulatory Proteins/biosynthesis
- Apoptosis Regulatory Proteins/genetics
- Autophagy/genetics
- Beclin-1
- Blotting, Western
- Cells, Cultured
- Diabetes Mellitus, Experimental
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Diabetic Cardiomyopathies/genetics
- Diabetic Cardiomyopathies/metabolism
- Diabetic Cardiomyopathies/pathology
- Female
- Gene Expression Regulation
- Humans
- In Situ Nick-End Labeling
- Male
- Membrane Proteins/biosynthesis
- Membrane Proteins/genetics
- Mice
- Mice, Obese
- Microscopy, Electron
- Myocardium/metabolism
- Myocardium/ultrastructure
- RNA/genetics
- RNA, Small Interfering/genetics
- Rats
- Rats, Zucker
- Signal Transduction/genetics
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Affiliation(s)
| | - Federica Riu
- School of Clinical Sciences, Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
| | - Parul Dixit
- Department of Physiology-HeartOtago, University of Otago, New Zealand
| | - Midori Edamatsu
- Department of Physiology-HeartOtago, University of Otago, New Zealand
| | - Pankaj Saxena
- Department of Cardiovascular Surgery, University of Otago, New Zealand
| | - Nathan S J Hamer
- Department of Physiology-HeartOtago, University of Otago, New Zealand
| | - Ivor F Galvin
- Department of Cardiovascular Surgery, University of Otago, New Zealand
| | - Richard W Bunton
- Department of Cardiovascular Surgery, University of Otago, New Zealand
| | | | - Greg Jones
- Department of Surgery, University of Otago, New Zealand
| | - Regis R Lamberts
- Department of Physiology-HeartOtago, University of Otago, New Zealand
| | - Costanza Emanueli
- School of Clinical Sciences, Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
| | - Paolo Madeddu
- School of Clinical Sciences, Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
| | - Rajesh Katare
- Department of Physiology-HeartOtago, University of Otago, New Zealand.
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