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An JR, Liu JT, Gao XM, Wang QF, Sun GY, Su JN, Zhang C, Yu JX, Yang YF, Shi Y. Effects of liraglutide on astrocyte polarization and neuroinflammation in db/db mice: focus on iron overload and oxidative stress. Front Cell Neurosci 2023; 17:1136070. [PMID: 37323581 PMCID: PMC10267480 DOI: 10.3389/fncel.2023.1136070] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 05/03/2023] [Indexed: 06/17/2023] Open
Abstract
Neuroinflammation plays a crucial role in the occurrence and development of cognitive impairment in type 2 diabetes mellitus (T2DM), but the specific injury mechanism is not fully understood. Astrocyte polarization has attracted new attention and has been shown to be directly and indirectly involved in neuroinflammation. Liraglutide has been shown to have beneficial effects on neurons and astrocytes. However, the specific protection mechanism still needs to be clarified. In this study, we assessed the levels of neuroinflammation and A1/A2-responsive astrocytes in the hippocampus of db/db mice and examined their relationships with iron overload and oxidative stress. First, in db/db mice, liraglutide alleviated the disturbance of glucose and lipid metabolism, increased the postsynaptic density, regulated the expression of NeuN and BDNF, and partially restored impaired cognitive function. Second, liraglutide upregulated the expression of S100A10 and downregulated the expression of GFAP and C3, and decreased the secretion of IL-1β, IL-18, and TNF-α, which may confirm that it regulates the proliferation of reactive astrocytes and A1/A2 phenotypes polarize and attenuate neuroinflammation. In addition, liraglutide reduced iron deposition in the hippocampus by reducing the expression of TfR1 and DMT1 and increasing the expression of FPN1; at the same time, liraglutide by up-regulating the levels of SOD, GSH, and SOD2 expression, as well as downregulation of MDA levels and NOX2 and NOX4 expression to reduce oxidative stress and lipid peroxidation. The above may attenuate A1 astrocyte activation. This study preliminarily explored the effect of liraglutide on the activation of different astrocyte phenotypes and neuroinflammation in the hippocampus of a T2DM model and further revealed its intervention effect on cognitive impairment in diabetes. Focusing on the pathological consequences of astrocytes may have important implications for the treatment of diabetic cognitive impairment.
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Affiliation(s)
- Ji-Ren An
- Liaoning Key Laboratory of Chinese Medicine Combining Disease and Syndrome of Diabetes, Liaoning University of Traditional Chinese Medicine, Shenyang, China
| | - Jun-Tong Liu
- Liaoning Key Laboratory of Chinese Medicine Combining Disease and Syndrome of Diabetes, Liaoning University of Traditional Chinese Medicine, Shenyang, China
| | - Xiao-Meng Gao
- College of Integrative Chinese and Western Medicine, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Qing-Feng Wang
- Liaoning Key Laboratory of Chinese Medicine Combining Disease and Syndrome of Diabetes, Liaoning University of Traditional Chinese Medicine, Shenyang, China
| | - Gui-Yan Sun
- Liaoning Key Laboratory of Chinese Medicine Combining Disease and Syndrome of Diabetes, Liaoning University of Traditional Chinese Medicine, Shenyang, China
| | - Jia-Nan Su
- Liaoning Key Laboratory of Chinese Medicine Combining Disease and Syndrome of Diabetes, Liaoning University of Traditional Chinese Medicine, Shenyang, China
| | - Chi Zhang
- Liaoning Key Laboratory of Chinese Medicine Combining Disease and Syndrome of Diabetes, Liaoning University of Traditional Chinese Medicine, Shenyang, China
| | - Jia-Xiang Yu
- Liaoning Key Laboratory of Chinese Medicine Combining Disease and Syndrome of Diabetes, Liaoning University of Traditional Chinese Medicine, Shenyang, China
| | - Yu-Feng Yang
- Liaoning Key Laboratory of Chinese Medicine Combining Disease and Syndrome of Diabetes, Liaoning University of Traditional Chinese Medicine, Shenyang, China
| | - Yan Shi
- Liaoning Key Laboratory of Chinese Medicine Combining Disease and Syndrome of Diabetes, Liaoning University of Traditional Chinese Medicine, Shenyang, China
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Ma Y, Liu H, Wang Y, Xuan J, Gao X, Ding H, Ma C, Chen Y, Yang Y. Roles of physical exercise-induced MiR-126 in cardiovascular health of type 2 diabetes. Diabetol Metab Syndr 2022; 14:169. [PMID: 36376958 PMCID: PMC9661802 DOI: 10.1186/s13098-022-00942-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 11/04/2022] [Indexed: 11/16/2022] Open
Abstract
Although physical activity is widely recommended for preventing and treating cardiovascular complications of type 2 diabetes mellitus (T2DM), the underlying mechanisms remain unknown. MicroRNA-126 (miR-126) is an angiogenetic regulator abundant in endothelial cells (ECs) and endothelial progenitor cells (EPCs). It is primarily involved in angiogenesis, inflammation and apoptosis for cardiovascular protection. According to recent studies, the levels of miR-126 in the myocardium and circulation are affected by exercise protocol. High-intensity interval training (HIIT) or moderate-and high-intensity aerobic exercise, whether acute or chronic, can increase circulating miR-126 in healthy adults. Chronic aerobic exercise can effectively rescue the reduction of myocardial and circulating miR-126 and vascular endothelial growth factor (VEGF) in diabetic mice against diabetic vascular injury. Resistance exercise can raise circulating VEGF levels, but it may have a little influence on circulating miR-126. The Several targets of miR-126 have been suggested for cardiovascular fitness, such as sprouty-related EVH1 domain-containing protein 1 (SPRED1), phosphoinositide-3-kinase regulatory subunit 2 (PIK3R2), vascular cell adhesion molecule 1 (VCAM1), high-mobility group box 1 (HMGB1), and tumor necrosis factor receptor-associated factor 7 (TRAF7). Here, we present a comprehensive review of the roles of miR-126 and its downstream proteins as exercise mechanisms, and propose that miR-126 can be applied as an exercise indicator for cardiovascular prescriptions and as a preventive or therapeutic target for cardiovascular complications in T2DM.
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Affiliation(s)
- Yixiao Ma
- Graduate School, Wuhan Sports University, Wuhan, 430079, China
| | - Hua Liu
- Laboratory of Physical Fitness Monitoring & Chronic Disease Intervention, Wuhan Sports University, Wuhan, 430079, China
| | - Yong Wang
- Laboratory of Physical Fitness Monitoring & Chronic Disease Intervention, Wuhan Sports University, Wuhan, 430079, China
| | - Junjie Xuan
- Graduate School, Wuhan Sports University, Wuhan, 430079, China
| | - Xing Gao
- Graduate School, Wuhan Sports University, Wuhan, 430079, China
| | - Huixian Ding
- Graduate School, Wuhan Sports University, Wuhan, 430079, China
| | - Chunlian Ma
- Laboratory of Physical Fitness Monitoring & Chronic Disease Intervention, Wuhan Sports University, Wuhan, 430079, China
| | - Yanfang Chen
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH, 45435, USA
| | - Yi Yang
- Hubei Key Laboratory of Exercise Training and Monitoring, Wuhan Sports University, Wuhan, 430079, China.
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Stanisic J, Koricanac G, Culafic T, Romic S, Stojiljkovic M, Kostic M, Ivkovic T, Tepavcevic S. The effects of low-intensity exercise on cardiac glycogenesis and glycolysis in male and ovariectomized female rats on a fructose-rich diet. J Food Biochem 2021; 45:e13930. [PMID: 34494282 DOI: 10.1111/jfbc.13930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 07/19/2021] [Accepted: 08/28/2021] [Indexed: 11/29/2022]
Abstract
We previously reported that low-intensity exercise prevented cardiac insulin resistance induced by a fructose-rich diet (FRD). To examine whether low-intensity exercise could prevent the disturbances of key molecules of cardiac glucose metabolism induced by FRD in male and ovariectomized (ovx) female rats, animals were exposed to 10% fructose solution (SF) or underwent both fructose diet and exercise (EF). Exercise prevented a decrease in cardiac GSK-3β phosphorylation induced by FRD in males (p < .001 vs. SF). It also prevented a decrease in PFK-2 phosphorylation in ovx females (p < .001 vs. SF) and increased the expression of PFK-2 in males (p < .05 vs. control). Exercise did not prevent a decrease in plasma membrane GLUT1 and GLUT4 levels in ovx females on FRD. The only effect of exercise on glucose transporters that could be indicated as beneficial is an augmented GLUT4 protein expression in males (p < .05 vs. control). Obtained results suggest that low-intensity exercise prevents harmful effects of FRD towards cardiac glycogenesis in males and glycolysis in ovx females. PRACTICAL APPLICATIONS: Low-intensity exercise, equivalent to brisk walking, was able to prevent disturbances in cardiac glycolysis regulation in ovx female and the glycogen synthesis pathway in male rats. In terms of human health, although molecular mechanisms of beneficial effects of exercise on cardiac glucose metabolism vary between genders, low-intensity running may be a useful non-pharmacological approach in the prevention of cardiac metabolic disorders in both men and postmenopausal women.
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Affiliation(s)
- Jelena Stanisic
- Laboratory for Molecular Biology and Endocrinology, Vinca Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Goran Koricanac
- Laboratory for Molecular Biology and Endocrinology, Vinca Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Tijana Culafic
- Laboratory for Molecular Biology and Endocrinology, Vinca Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Snjezana Romic
- Laboratory for Molecular Biology and Endocrinology, Vinca Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Mojca Stojiljkovic
- Laboratory for Molecular Biology and Endocrinology, Vinca Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Milan Kostic
- Laboratory for Molecular Biology and Endocrinology, Vinca Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Tamara Ivkovic
- Laboratory for Molecular Biology and Endocrinology, Vinca Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Snezana Tepavcevic
- Laboratory for Molecular Biology and Endocrinology, Vinca Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
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Yosefy O, Sharon B, Yagil C, Shlapoberski M, Livoff A, Novitski I, Beeri R, Yagil Y, Yosefy C. Diabetes induces remodeling of the left atrial appendage independently of atrial fibrillation in a rodent model of type-2 diabetes. Cardiovasc Diabetol 2021; 20:149. [PMID: 34301258 PMCID: PMC8306366 DOI: 10.1186/s12933-021-01347-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 07/15/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Diabetic patients have an increased predisposition to thromboembolic events, in most cases originating from thrombi in the left atrial appendage (LAA). Remodeling of the LAA, which predisposes to thrombi formation, has been previously described in diabetic patients with atrial fibrillation, but whether remodeling of the LAA occurs in diabetics also in the absence of atrial fibrillation is unknown. To investigate the contribution of diabetes, as opposed to atrial fibrillation, to remodeling of the LAA, we went from humans to the animal model. METHODS We studied by echocardiography the structure and function of the heart over multiple time points during the evolution of diabetes in the Cohen diabetic sensitive rat (CDs/y) provided diabetogenic diet over a period of 4 months; CDs/y provided regular diet and the Cohen diabetic resistant (CDr/y), which do not develop diabetes, served as controls. All animals were in sinus rhythm throughout the study period. RESULTS Compared to controls, CDs/y developed during the evolution of diabetes a greater heart mass, larger left atrial diameter, wider LAA orifice, increased LAA depth, greater end-diastolic and end-systolic diameter, and lower E/A ratio-all indicative of remodeling of the LAA and left atrium (LA), as well as the development of left ventricular diastolic dysfunction. To investigate the pathophysiology involved, we studied the histology of the hearts at the end of the study. We found in diabetic CDs/y, but not in any of the other groups, abundance of glycogen granules in the atrial appendages , atria and ventricles, which may be of significance as glycogen granules have previously been associated with cell and organ dysfunction in the diabetic heart. CONCLUSIONS We conclude that our rodent model of diabetes, which was in sinus rhythm, reproduced structural and functional alterations previously observed in hearts of human diabetics with atrial fibrillation. Remodeling of the LAA and of the LA in our model was unrelated to atrial fibrillation and associated with accumulation of glycogen granules. We suggest that myocardial accumulation of glycogen granules is related to the development of diabetes and may play a pathophysiological role in remodeling of the LAA and LA, which predisposes to atrial fibrillation, thromboembolic events and left ventricular diastolic dysfunction in the diabetic heart.
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Affiliation(s)
- Or Yosefy
- Department of Cardiology, Barzilai University Medical Center, 2 Hahistadrut Street, 78278, Ashkelon, Israel
| | - Barucha Sharon
- Department of Cardiology, Barzilai University Medical Center, 2 Hahistadrut Street, 78278, Ashkelon, Israel
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Chana Yagil
- Laboratory for Molecular Medicine and Israeli Rat Genome Center, Barzilai University Medical Center, 2 Hahistadrut Street, 78278, Ashkelon, Israel
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Mark Shlapoberski
- Department of Pathology, Barzilai University Medical Center, Ashkelon, Israel
| | - Alejandro Livoff
- Department of Pathology, Barzilai University Medical Center, Ashkelon, Israel
| | - Ilana Novitski
- Department of Pathology, Barzilai University Medical Center, Ashkelon, Israel
| | - Ronen Beeri
- Diagnostic Cardiology Unit, Heart Institute, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Yoram Yagil
- Laboratory for Molecular Medicine and Israeli Rat Genome Center, Barzilai University Medical Center, 2 Hahistadrut Street, 78278, Ashkelon, Israel.
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel.
| | - Chaim Yosefy
- Department of Cardiology, Barzilai University Medical Center, 2 Hahistadrut Street, 78278, Ashkelon, Israel.
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheba, Israel.
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Exercise as A Potential Therapeutic Target for Diabetic Cardiomyopathy: Insight into the Underlying Mechanisms. Int J Mol Sci 2019; 20:ijms20246284. [PMID: 31842522 PMCID: PMC6940726 DOI: 10.3390/ijms20246284] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/09/2019] [Accepted: 12/10/2019] [Indexed: 02/06/2023] Open
Abstract
Diabetes mellitus is associated with cardiovascular, ophthalmic, and renal comorbidities. Among these, diabetic cardiomyopathy (DCM) causes the most severe symptoms and is considered to be a major health problem worldwide. Exercise is widely known as an effective strategy for the prevention and treatment of many chronic diseases. Importantly, the onset of complications arising due to diabetes can be delayed or even prevented by exercise. Regular exercise is reported to have positive effects on diabetes mellitus and the development of DCM. The protective effects of exercise include prevention of cardiac apoptosis, fibrosis, oxidative stress, and microvascular diseases, as well as improvement in cardiac mitochondrial function and calcium regulation. This review summarizes the recent scientific findings to describe the potential mechanisms by which exercise may prevent DCM and heart failure.
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6
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Dysregulation of Glycogen Metabolism with Concomitant Spatial Memory Dysfunction in Type 2 Diabetes: Potential Beneficial Effects of Chronic Exercise. ADVANCES IN NEUROBIOLOGY 2019; 23:363-383. [DOI: 10.1007/978-3-030-27480-1_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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7
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Eshima H, Tamura Y, Kakehi S, Nakamura K, Kurebayashi N, Murayama T, Kakigi R, Sakurai T, Kawamori R, Watada H. Dysfunction of muscle contraction with impaired intracellular Ca 2+ handling in skeletal muscle and the effect of exercise training in male db/db mice. J Appl Physiol (1985) 2018; 126:170-182. [PMID: 30433865 DOI: 10.1152/japplphysiol.00048.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Type 2 diabetes is characterized by reduced contractile force production and increased fatigability of skeletal muscle. While the maintenance of Ca2+ homeostasis during muscle contraction is a requisite for optimal contractile function, the mechanisms underlying muscle contractile dysfunction in type 2 diabetes are unclear. Here, we investigated skeletal muscle contractile force and Ca2+ flux during contraction and pharmacological stimulation in type 2 diabetic model mice ( db/db mice). Furthermore, we investigated the effect of treadmill exercise training on muscle contractile function. In male db/db mice, muscle contractile force and peak Ca2+ levels were both lower during tetanic stimulation of the fast-twitch muscles, while Ca2+ accumulation was higher after stimulation compared with control mice. While 6 wk of exercise training did not improve glucose tolerance, exercise did improve muscle contractile dysfunction, peak Ca2+ levels, and Ca2+ accumulation following stimulation in male db/db mice. These data suggest that dysfunctional Ca2+ flux may contribute to skeletal muscle contractile dysfunction in type 2 diabetes and that exercise training may be a promising therapeutic approach for dysfunctional skeletal muscle contraction. NEW & NOTEWORTHY The purpose of this study was to examine muscle contractile function and Ca2+ regulation as well as the effect of exercise training in skeletal muscle in obese diabetic mice ( db/db). We observed impairment of muscle contractile force and Ca2+ regulation in a male type 2 diabetic animal model. These dysfunctions in muscle were improved by 6 wk of exercise training.
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Affiliation(s)
- Hiroaki Eshima
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan.,The Japan Society for the Promotion of Science , Tokyo , Japan
| | - Yoshifumi Tamura
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Saori Kakehi
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Kyoko Nakamura
- Department of Physiology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Nagomi Kurebayashi
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Takashi Murayama
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Ryo Kakigi
- Department of Physiology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Takashi Sakurai
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Ryuzo Kawamori
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Hirotaka Watada
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Center for Therapeutic Innovations in Diabetes, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Center for Molecular Diabetology, Juntendo University Graduate School of Medicine , Tokyo , Japan
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8
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Shima T, Jesmin S, Matsui T, Soya M, Soya H. Differential effects of type 2 diabetes on brain glycometabolism in rats: focus on glycogen and monocarboxylate transporter 2. J Physiol Sci 2018; 68:69-75. [PMID: 27987117 PMCID: PMC10717161 DOI: 10.1007/s12576-016-0508-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 11/23/2016] [Indexed: 12/21/2022]
Abstract
Astrocyte-neuron lactate shuttle (ANLS) is a pathway that supplies glycogen-derived lactate to active neurons via monocarboxylate transporter 2 (MCT2), and is important for maintaining brain functions. Our study revealed alterations of ANLS with hippocampal hyper-glycogen levels and downregulated MCT2 protein levels underlying hippocampal dysfunctions as a complication in type 2 diabetic (T2DM) animals. Since T2DM rats exhibit brain dysfunctions involving several brain regions, we examined whether there might also be T2DM effects on ANLS's disturbances in other brain loci. OLETF rats exhibited significantly higher glycogen levels in the hippocampus, hypothalamus, and cerebral cortex than did LETO rats. MCT2 protein levels in OLETF rats decreased significantly in the hippocampus and hypothalamus compared to their controls, but a significant correlation with glycogen levels was only observed in the hippocampus. This suggests that the hippocampus may be more vulnerable to T2DM compared to other brain regions in the context of ANLS disruption.
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Affiliation(s)
- Takeru Shima
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan
| | - Subrina Jesmin
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan
- Department of Sports Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan
| | - Takashi Matsui
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan
- Department of Sports Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan
| | - Mariko Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan
| | - Hideaki Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan.
- Department of Sports Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan.
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9
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Maria Z, Campolo AR, Scherlag BJ, Ritchey JW, Lacombe VA. Dysregulation of insulin-sensitive glucose transporters during insulin resistance-induced atrial fibrillation. Biochim Biophys Acta Mol Basis Dis 2017; 1864:987-996. [PMID: 29291943 DOI: 10.1016/j.bbadis.2017.12.038] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 11/29/2017] [Accepted: 12/23/2017] [Indexed: 11/18/2022]
Abstract
Diabetes has been identified as major risk factor for atrial fibrillation (AF). Although glucose and insulin disturbances during diabetes may affect atrial function, little is known about the potential pathogenic role of glucose metabolism during AF. Glucose transport into the cell via glucose transporters (GLUTs) is the rate-limiting step of glucose utilization. Although GLUT4 is the major isoform, GLUT8 has emerged as a novel insulin-sensitive cardiac isoform. We hypothesized that atrial glucose homeostasis will be impaired during insulin resistance-induced AF. AF was induced by transesophageal atrial pacing in healthy mice and following a long-term high-fat-diet-induced insulin resistance. Active cell surface GLUT content was measured using the biotinylated photolabeling assay in the intact perfused heart. Atrial fibrosis, advanced glycation end products (AGEs) and glycogen were measured in the atria using histological analyses. Animals fed a high-fat-diet were obese and mildly hyperglycemic, and developed insulin resistance compared to controls. Insulin-resistant (IR) animals demonstrated an increased vulnerability to induced AF, as well as spontaneous AF. Insulin-stimulated translocation of GLUT4 and GLUT8 was down-regulated in the atria of IR animals, as well as their total protein expression. We also reported the absence of fibrosis, glycogen and AGE accumulation in the atria of IR animals. In the absence of structural remodeling and atrial fibrosis, these data suggest that insulin signaling dysregulation, resulting in impaired glucose transport in the atria, could provide a metabolic arrhythmogenic substrate and be a novel early pathogenic factor of AF.
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Affiliation(s)
- Zahra Maria
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, USA; Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Allison R Campolo
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, USA; Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Benjamin J Scherlag
- Department of Internal Medicine, University of Oklahoma, Oklahoma City, OK, USA
| | - Jerry W Ritchey
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK, USA
| | - Véronique A Lacombe
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, USA; Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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10
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Bockus LB, Matsuzaki S, Vadvalkar SS, Young ZT, Giorgione JR, Newhardt MF, Kinter M, Humphries KM. Cardiac Insulin Signaling Regulates Glycolysis Through Phosphofructokinase 2 Content and Activity. J Am Heart Assoc 2017; 6:e007159. [PMID: 29203581 PMCID: PMC5779029 DOI: 10.1161/jaha.117.007159] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 10/23/2017] [Indexed: 01/18/2023]
Abstract
BACKGROUND The healthy heart has a dynamic capacity to respond and adapt to changes in nutrient availability. Diabetes mellitus disrupts this metabolic flexibility and promotes cardiomyopathy through mechanisms that are not completely understood. Phosphofructokinase 2 (PFK-2) is a primary regulator of cardiac glycolysis and substrate selection, yet its regulation under normal and pathological conditions is unknown. This study was undertaken to determine how changes in insulin signaling affect PFK-2 content, activity, and cardiac metabolism. METHODS AND RESULTS Streptozotocin-induced diabetes mellitus, high-fat diet feeding, and fasted mice were used to identify how decreased insulin signaling affects PFK-2 and cardiac metabolism. Primary adult cardiomyocytes were used to define the mechanisms that regulate PFK-2 degradation. Both type 1 diabetes mellitus and a high-fat diet induced a significant decrease in cardiac PFK-2 protein content without affecting its transcript levels. Overnight fasting also induced a decrease in PFK-2, suggesting it is rapidly degraded in the absence of insulin signaling. An unbiased metabolomic study demonstrated that decreased PFK-2 in fasted animals is accompanied by an increase in glycolytic intermediates upstream of phosphofructokianse-1, whereas those downstream are diminished. Mechanistic studies using cardiomyocytes showed that, in the absence of insulin signaling, PFK-2 is rapidly degraded via both proteasomal- and chaperone-mediated autophagy. CONCLUSIONS The loss of PFK-2 content as a result of reduced insulin signaling impairs the capacity to dynamically regulate glycolysis and elevates the levels of early glycolytic intermediates. Although this may be beneficial in the fasted state to conserve systemic glucose, it represents a pathological impairment in diabetes mellitus.
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MESH Headings
- Animals
- Autophagy
- Cells, Cultured
- Diabetes Mellitus, Experimental/blood
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/enzymology
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 1/blood
- Diabetes Mellitus, Type 1/chemically induced
- Diabetes Mellitus, Type 1/enzymology
- Diabetes Mellitus, Type 1/pathology
- Diabetic Cardiomyopathies/blood
- Diabetic Cardiomyopathies/enzymology
- Diabetic Cardiomyopathies/etiology
- Diet, Fat-Restricted
- Diet, High-Fat
- Down-Regulation
- Enzyme Stability
- Fasting/blood
- Glycolysis
- Insulin/blood
- Mice, Inbred C57BL
- Molecular Chaperones/metabolism
- Myocardium/enzymology
- Myocardium/pathology
- Phosphofructokinase-2/genetics
- Phosphofructokinase-2/metabolism
- Phosphorylation
- Proteasome Endopeptidase Complex/metabolism
- Proteolysis
- Signal Transduction
- Streptozocin
- Time Factors
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Affiliation(s)
- Lee B Bockus
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Satoshi Matsuzaki
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Shraddha S Vadvalkar
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Zachary T Young
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Jennifer R Giorgione
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Maria F Newhardt
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Michael Kinter
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Kenneth M Humphries
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
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Molecular mechanisms of cardiac pathology in diabetes - Experimental insights. Biochim Biophys Acta Mol Basis Dis 2017; 1864:1949-1959. [PMID: 29109032 DOI: 10.1016/j.bbadis.2017.10.035] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 10/09/2017] [Accepted: 10/27/2017] [Indexed: 12/11/2022]
Abstract
Diabetic cardiomyopathy is a distinct pathology independent of co-morbidities such as coronary artery disease and hypertension. Diminished glucose uptake due to impaired insulin signaling and decreased expression of glucose transporters is associated with a shift towards increased reliance on fatty acid oxidation and reduced cardiac efficiency in diabetic hearts. The cardiac metabolic profile in diabetes is influenced by disturbances in circulating glucose, insulin and fatty acids, and alterations in cardiomyocyte signaling. In this review, we focus on recent preclinical advances in understanding the molecular mechanisms of diabetic cardiomyopathy. Genetic manipulation of cardiomyocyte insulin signaling intermediates has demonstrated that partial cardiac functional rescue can be achieved by upregulation of the insulin signaling pathway in diabetic hearts. Inconsistent findings have been reported relating to the role of cardiac AMPK and β-adrenergic signaling in diabetes, and systemic administration of agents targeting these pathways appear to elicit some cardiac benefit, but whether these effects are related to direct cardiac actions is uncertain. Overload of cardiomyocyte fuel storage is evident in the diabetic heart, with accumulation of glycogen and lipid droplets. Cardiac metabolic dysregulation in diabetes has been linked with oxidative stress and autophagy disturbance, which may lead to cell death induction, fibrotic 'backfill' and cardiac dysfunction. This review examines the weight of evidence relating to the molecular mechanisms of diabetic cardiomyopathy, with a particular focus on metabolic and signaling pathways. Areas of uncertainty in the field are highlighted and important knowledge gaps for further investigation are identified. This article is part of a Special issue entitled Cardiac adaptations to obesity, diabetes and insulin resistance, edited by Professors Jan F.C. Glatz, Jason R.B. Dyck and Christine Des Rosiers.
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Shima T, Matsui T, Jesmin S, Okamoto M, Soya M, Inoue K, Liu YF, Torres-Aleman I, McEwen BS, Soya H. Moderate exercise ameliorates dysregulated hippocampal glycometabolism and memory function in a rat model of type 2 diabetes. Diabetologia 2017; 60:597-606. [PMID: 27928614 DOI: 10.1007/s00125-016-4164-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 11/03/2016] [Indexed: 12/15/2022]
Abstract
AIMS/HYPOTHESIS Type 2 diabetes is likely to be an independent risk factor for hippocampal-based memory dysfunction, although this complication has yet to be investigated in detail. As dysregulated glycometabolism in peripheral tissues is a key symptom of type 2 diabetes, it is hypothesised that diabetes-mediated memory dysfunction is also caused by hippocampal glycometabolic dysfunction. If so, such dysfunction should also be ameliorated with moderate exercise by normalising hippocampal glycometabolism, since 4 weeks of moderate exercise enhances memory function and local hippocampal glycogen levels in normal animals. METHODS The hippocampal glycometabolism in OLETF rats (model of human type 2 diabetes) was assessed and, subsequently, the effects of exercise on memory function and hippocampal glycometabolism were investigated. RESULTS OLETF rats, which have memory dysfunction, exhibited higher levels of glycogen in the hippocampus than did control rats, and breakdown of hippocampal glycogen with a single bout of exercise remained unimpaired. However, OLETF rats expressed lower levels of hippocampal monocarboxylate transporter 2 (MCT2, a transporter for lactate to neurons). Four weeks of moderate exercise improved spatial memory accompanied by further increase in hippocampal glycogen levels and restoration of MCT2 expression independent of neurotrophic factor and clinical symptoms in OLETF rats. CONCLUSIONS/INTERPRETATION Our findings are the first to describe detailed profiles of glycometabolism in the type 2 diabetic hippocampus and to show that 4 weeks of moderate exercise improves memory dysfunction in type 2 diabetes via amelioration of dysregulated hippocampal glycometabolism. Dysregulated hippocampal lactate-transport-related glycometabolism is a possible aetiology of type-2-diabetes-mediated memory dysfunction.
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Affiliation(s)
- Takeru Shima
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan
| | - Takashi Matsui
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan
- Department of Sports Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), University of Tsukuba, Tsukuba, Ibaraki, Japan
- Cajal Institute, CSIC, Madrid, Spain
| | - Subrina Jesmin
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan
- Department of Sports Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Masahiro Okamoto
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA
| | - Mariko Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan
| | - Koshiro Inoue
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan
| | - Yu-Fan Liu
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan
| | | | - Bruce S McEwen
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA
| | - Hideaki Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8574, Japan.
- Department of Sports Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), University of Tsukuba, Tsukuba, Ibaraki, Japan.
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Song P, Onishi A, Koepsell H, Vallon V. Sodium glucose cotransporter SGLT1 as a therapeutic target in diabetes mellitus. Expert Opin Ther Targets 2016; 20:1109-25. [PMID: 26998950 DOI: 10.1517/14728222.2016.1168808] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Glycemic control is important in diabetes mellitus to minimize the progression of the disease and the risk of potentially devastating complications. Inhibition of the sodium-glucose cotransporter SGLT2 induces glucosuria and has been established as a new anti-hyperglycemic strategy. SGLT1 plays a distinct and complementing role to SGLT2 in glucose homeostasis and, therefore, SGLT1 inhibition may also have therapeutic potential. AREAS COVERED This review focuses on the physiology of SGLT1 in the small intestine and kidney and its pathophysiological role in diabetes. The therapeutic potential of SGLT1 inhibition, alone as well as in combination with SGLT2 inhibition, for anti-hyperglycemic therapy are discussed. Additionally, this review considers the effects on other SGLT1-expressing organs like the heart. EXPERT OPINION SGLT1 inhibition improves glucose homeostasis by reducing dietary glucose absorption in the intestine and by increasing the release of gastrointestinal incretins like glucagon-like peptide-1. SGLT1 inhibition has a small glucosuric effect in the normal kidney and this effect is increased in diabetes and during inhibition of SGLT2, which deliver more glucose to SGLT1 in late proximal tubule. In short-term studies, inhibition of SGLT1 and combined SGLT1/SGLT2 inhibition appeared to be safe. More data is needed on long-term safety and cardiovascular consequences of SGLT1 inhibition.
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Affiliation(s)
- Panai Song
- a Division of Nephrology & Hypertension, Department of Medicine , University of California San Diego , La Jolla , CA , USA.,b VA San Diego Healthcare System , San Diego , CA , USA.,c Department of Nephrology, Second Xiangya Hospital , Central South University , Changsha , China
| | - Akira Onishi
- a Division of Nephrology & Hypertension, Department of Medicine , University of California San Diego , La Jolla , CA , USA.,b VA San Diego Healthcare System , San Diego , CA , USA.,d Division of Nephrology, Department of Medicine , Jichi Medical University , Shimotsuke , Japan
| | - Hermann Koepsell
- e Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute , University of Würzburg , Würzburg , Germany
| | - Volker Vallon
- a Division of Nephrology & Hypertension, Department of Medicine , University of California San Diego , La Jolla , CA , USA.,b VA San Diego Healthcare System , San Diego , CA , USA.,f Department of Pharmacology , University of California San Diego , La Jolla , CA , USA
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Hafstad AD, Boardman N, Aasum E. How exercise may amend metabolic disturbances in diabetic cardiomyopathy. Antioxid Redox Signal 2015; 22:1587-605. [PMID: 25738326 PMCID: PMC4449627 DOI: 10.1089/ars.2015.6304] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
SIGNIFICANCE Over-nutrition and sedentary lifestyle has led to a worldwide increase in obesity, insulin resistance, and type 2 diabetes (T2D) associated with an increased risk of development of cardiovascular disorders. Diabetic cardiomyopathy, independent of hypertension or coronary disease, is induced by a range of systemic changes and may through multiple processes result in functional and structural cardiac derangements. The pathogenesis of this cardiomyopathy is complex and multifactorial, and it will eventually lead to reduced cardiac working capacity and increased susceptibility to ischemic injury. RECENT ADVANCES Metabolic disturbances such as altered lipid handling and substrate utilization, decreased mechanical efficiency, mitochondrial dysfunction, disturbances in nonoxidative glucose pathways, and increased oxidative stress are hallmarks of diabetic cardiomyopathy. Interestingly, several of these disturbances are found to precede the development of cardiac dysfunction. CRITICAL ISSUES Exercise training is effective in the prevention and treatment of obesity and T2D. In addition to its beneficial influence on diabetes/obesity-related systemic changes, it may also amend many of the metabolic disturbances characterizing the diabetic myocardium. These changes are due to both indirect effects, exercise-mediated systemic changes, and direct effects originating from the high contractile activity of the heart during physical training. FUTURE DIRECTIONS Revealing the molecular mechanisms behind the beneficial effects of exercise training is of considerable scientific value to generate evidence-based therapy and in the development of new treatment strategies.
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Affiliation(s)
- Anne D Hafstad
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Neoma Boardman
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Ellen Aasum
- Cardiovascular Research Group, Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
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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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16
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Delbridge LMD, Mellor KM, Taylor DJR, Gottlieb RA. Myocardial autophagic energy stress responses--macroautophagy, mitophagy, and glycophagy. Am J Physiol Heart Circ Physiol 2015; 308:H1194-204. [PMID: 25747748 DOI: 10.1152/ajpheart.00002.2015] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 03/02/2015] [Indexed: 12/26/2022]
Abstract
An understanding of the role of autophagic processes in the management of cardiac metabolic stress responses is advancing rapidly and progressing beyond a conceptualization of the autophagosome as a simple cell recycling depot. The importance of autophagy dysregulation in diabetic cardiomyopathy and in ischemic heart disease - both conditions comprising the majority of cardiac disease burden - has now become apparent. New findings have revealed that specific autophagic processes may operate in the cardiomyocyte, specialized for selective recognition and management of mitochondria and glycogen particles in addition to protein macromolecular structures. Thus mitophagy, glycophagy, and macroautophagy regulatory pathways have become the focus of intensive experimental effort, and delineating the signaling pathways involved in these processes offers potential for targeted therapeutic intervention. Chronically elevated macroautophagic activity in the diabetic myocardium is generally observed in association with structural and functional cardiomyopathy; yet there are also numerous reports of detrimental effect of autophagy suppression in diabetes. Autophagy induction has been identified as a key component of protective mechanisms that can be recruited to support the ischemic heart, but in this setting benefit may be mitigated by adverse downstream autophagic consequences. Recent report of glycophagy upregulation in diabetic cardiomyopathy opens up a novel area of investigation. Similarly, a role for glycogen management in ischemia protection through glycophagy initiation is an exciting prospect under investigation.
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Affiliation(s)
- Lea M D Delbridge
- Department of Physiology, University of Melbourne, Melbourne, Victoria, Australia;
| | - Kimberley M Mellor
- Department of Physiology, University of Melbourne, Melbourne, Victoria, Australia; Department of Physiology, University of Auckland, New Zealand; and
| | - David J R Taylor
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California
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Lambert JE, Myslicki JP, Bomhof MR, Belke DD, Shearer J, Reimer RA. Exercise training modifies gut microbiota in normal and diabetic mice. Appl Physiol Nutr Metab 2015; 40:749-52. [PMID: 25962839 DOI: 10.1139/apnm-2014-0452] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cecal microbiota from type 2 diabetic (db/db) and control (db/(+)) mice was obtained following 6 weeks of sedentary or exercise activity. qPCR analysis revealed a main effect of exercise, with greater abundance of select Firmicutes species and lower Bacteroides/Prevotella spp. in both normal and diabetic exercised mice compared with sedentary counterparts. Conversely, Bifidobacterium spp. was greater in exercised normal but not diabetic mice (exercise × diabetes interaction). How exercise influences gut microbiota requires further investigation.
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Affiliation(s)
- Jennifer E Lambert
- a Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Jason P Myslicki
- a Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Marc R Bomhof
- a Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Darrell D Belke
- a Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Jane Shearer
- a Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada.,b Department of Biochemistry and Molecular Biology, Cumming School of Medicine; University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Raylene A Reimer
- a Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada.,b Department of Biochemistry and Molecular Biology, Cumming School of Medicine; University of Calgary, Calgary, AB T2N 4N1, Canada
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Myslicki JP, Belke DD, Shearer J. Role of O-GlcNAcylation in nutritional sensing, insulin resistance and in mediating the benefits of exercise. Appl Physiol Nutr Metab 2014; 39:1205-13. [PMID: 25203141 DOI: 10.1139/apnm-2014-0122] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this review is to highlight the role of O-linked β-N-acetylglucosamine (O-GlcNAc) protein modification in metabolic disease states and to summarize current knowledge of how exercise affects this important post-translational signalling pathway. O-GlcNAc modification is an intracellular tool capable of integrating energy supply with demand. The accumulation of excess energy associated with obesity and insulin resistance is mediated, in part, by the hexosamine biosynthetic pathway (HBP), which results in the O-GlcNAcylation of a myriad of proteins, thereby affecting their respective function, stability, and localization. Insulin resistance is related to the excessive O-GlcNAcylation of key metabolic proteins causing a chronic blunting of insulin signalling pathways and precipitating the accompanying pathologies, such as heart and kidney disease. Lifestyle modifications such as diet and exercise also modify the pathway. Exercise is a front-line and cost-effective therapeutic approach for insulin resistance, and recent work shows that the intervention can alter O-GlcNAc gene expression, signalling, and protein modification. However, there is currently no consensus on the effect of frequency, intensity, type, and duration of exercise on O-GlcNAc modification, the HBP, and its related enzymes. On one end of the spectrum, mild, prolonged swim training reduces O-GlcNAcylation, while on the other end, higher intensity treadmill running increases cardiac protein O-GlcNAc modification. Clearly, a balance between acute and chronic stress of exercise is needed to reap the benefits of the intervention on O-GlcNAc signalling.
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Affiliation(s)
- Jason P Myslicki
- a Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
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19
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Stapleton DI, Lau X, Flores M, Trieu J, Gehrig SM, Chee A, Naim T, Lynch GS, Koopman R. Dysfunctional muscle and liver glycogen metabolism in mdx dystrophic mice. PLoS One 2014; 9:e91514. [PMID: 24626262 PMCID: PMC3953428 DOI: 10.1371/journal.pone.0091514] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 02/11/2014] [Indexed: 12/25/2022] Open
Abstract
Background Duchenne muscular dystrophy (DMD) is a severe, genetic muscle wasting disorder characterised by progressive muscle weakness. DMD is caused by mutations in the dystrophin (dmd) gene resulting in very low levels or a complete absence of the dystrophin protein, a key structural element of muscle fibres which is responsible for the proper transmission of force. In the absence of dystrophin, muscle fibres become damaged easily during contraction resulting in their degeneration. DMD patients and mdx mice (an animal model of DMD) exhibit altered metabolic disturbances that cannot be attributed to the loss of dystrophin directly. We tested the hypothesis that glycogen metabolism is defective in mdx dystrophic mice. Results Dystrophic mdx mice had increased skeletal muscle glycogen (79%, (P<0.01)). Skeletal muscle glycogen synthesis is initiated by glycogenin, the expression of which was increased by 50% in mdx mice (P<0.0001). Glycogen synthase activity was 12% higher (P<0.05) but glycogen branching enzyme activity was 70% lower (P<0.01) in mdx compared with wild-type mice. The rate-limiting enzyme for glycogen breakdown, glycogen phosphorylase, had 62% lower activity (P<0.01) in mdx mice resulting from a 24% reduction in PKA activity (P<0.01). In mdx mice glycogen debranching enzyme expression was 50% higher (P<0.001) together with starch-binding domain protein 1 (219% higher; P<0.01). In addition, mdx mice were glucose intolerant (P<0.01) and had 30% less liver glycogen (P<0.05) compared with control mice. Subsequent analysis of the enzymes dysregulated in skeletal muscle glycogen metabolism in mdx mice identified reduced glycogenin protein expression (46% less; P<0.05) as a possible cause of this phenotype. Conclusion We identified that mdx mice were glucose intolerant, and had increased skeletal muscle glycogen but reduced amounts of liver glycogen.
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Affiliation(s)
- David I Stapleton
- Department of Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Xianzhong Lau
- Department of Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Marcelo Flores
- Department of Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jennifer Trieu
- Department of Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Stefan M Gehrig
- Department of Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Annabel Chee
- Department of Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Timur Naim
- Department of Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Gordon S Lynch
- Department of Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - René Koopman
- Department of Physiology, The University of Melbourne, Melbourne, Victoria, Australia
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20
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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: 54] [Impact Index Per Article: 4.9] [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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Cox EJ, Marsh SA. Exercise and diabetes have opposite effects on the assembly and O-GlcNAc modification of the mSin3A/HDAC1/2 complex in the heart. Cardiovasc Diabetol 2013; 12:101. [PMID: 23835259 PMCID: PMC3708830 DOI: 10.1186/1475-2840-12-101] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 06/30/2013] [Indexed: 01/08/2023] Open
Abstract
Background Exercise causes physiological cardiac hypertrophy and benefits the diabetic heart. Mammalian switch-independent 3A (mSin3A) and histone deacetylases (HDACs) 1 and 2 regulate hypertrophic genes through associations with the DNA binding proteins repressor element-1 silencing transcription factor (REST) and O-linked β-N-acetylglucosamine transferase (OGT). O-linked β-N-acetylglucosamine (O-GlcNAc) is a glucose derivative that is chronically elevated in diabetic hearts, and a previous study showed that exercise reduces cardiac O-GlcNAc. We hypothesized that O-GlcNAc and OGT would physically associate with mSin3A/HDAC1/2 in the heart, and that this interaction would be altered by diabetes and exercise. Methods 8-week-old type 2 diabetic db/db (db) and non-diabetic C57 mice were randomized to treadmill exercise or sedentary groups for 1 or 4 weeks. Results O-GlcNAc was significantly higher in db hearts and increased with exercise. Db hearts showed lower levels of mSin3A, HDAC1, and HDAC2 protein, but higher levels of HDAC2 mRNA and HDAC1/2 deacetylase activity. Elevated HDAC activity was associated with significantly blunted expression of α-actin and brain natriuretic peptide in db hearts. In sedentary db hearts, co-immunoprecipitation assays showed that mSin3A and OGT were less associated with HDAC1 and HDAC2, respectively, compared to sedentary C57 controls; however, exercise removed these differences. Conclusions These data indicate that diabetes and exercise oppositely affect interactions between pro-hypertrophic transcription factors, and suggest that an increase in total cardiac O-GlcNAc is a mechanism by which exercise benefits type 2 diabetic hearts.
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Mellor KM, Reichelt ME, Delbridge LM. Autophagic predisposition in the insulin resistant diabetic heart. Life Sci 2013; 92:616-20. [DOI: 10.1016/j.lfs.2012.03.042] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 03/21/2012] [Accepted: 03/24/2012] [Indexed: 01/30/2023]
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Laher I, Beam J, Botta A, Barendregt R, Sulistyoningrum D, Devlin A, Rheault M, Ghosh S. Short-term exercise worsens cardiac oxidative stress and fibrosis in 8-month-old db/db mice by depleting cardiac glutathione. Free Radic Res 2012; 47:44-54. [PMID: 23039789 DOI: 10.3109/10715762.2012.737463] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Moderate exercise improves cardiac antioxidant status in young humans and animals with Type-2 diabetes (T2D). Given that both diabetes and advancing age synergistically decrease antioxidant expression in most tissues, it is unclear whether exercise can upregulate cardiac antioxidants in chronic animal models of T2D. To this end, 8-month-old T2D and normoglycemic mice were exercised for 3 weeks, and cardiac redox status was evaluated. As expected, moderate exercise increased cardiac antioxidants and attenuated oxidative damage in normoglycemic mice. In contrast, similar exercise protocol in 8-month-old db/db mice worsened cardiac oxidative damage, which was associated with a specific dysregulation of glutathione (GSH) homeostasis. Expression of enzymes for GSH biosynthesis [γ-glutamylcysteine synthase, glutathione reductase] as well as for GSH-mediated detoxification (glutathione peroxidase, glutathione-S-transferase) was lower, while toxic metabolites dependent on GSH for clearance (4-hydroxynonenal) were increased in exercised diabetic mice hearts. To validate GSH loss as an important factor for such aggravated damage, daily administration of GSH restored cardiac GSH levels in exercised diabetic mice. Such supplementation attenuated both oxidative damage and fibrotic changes in the myocardium. Expression of transforming growth factor beta (TGF-β) and its regulated genes which are responsible for such profibrotic changes were also attenuated with GSH supplementation. These novel findings in a long-term T2D animal model demonstrate that short-term exercise by itself can deplete cardiac GSH and aggravate cardiac oxidative stress. As GSH administration conferred protection in 8-month-old diabetic mice undergoing exercise, supplementation with GSH-enhancing agents may be beneficial in elderly diabetic patients undergoing exercise.
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Affiliation(s)
- Ismail Laher
- Department of Pharmacology and Therapeutics, University of British Columbia, BC, Canada
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Besford QA, Sullivan MA, Zheng L, Gilbert RG, Stapleton D, Gray-Weale A. The structure of cardiac glycogen in healthy mice. Int J Biol Macromol 2012; 51:887-91. [PMID: 22782068 DOI: 10.1016/j.ijbiomac.2012.06.037] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 05/06/2012] [Accepted: 06/26/2012] [Indexed: 12/12/2022]
Abstract
Transmission electron micrographs of glycogen extracted from healthy mouse hearts reveal aggregate structures around 133 nm in diameter. These structures are similar to, but on average somewhat smaller than, the α-particles of glycogen found in mammalian liver. Like the larger liver glycogens, these new particles in cardiac tissue appear to be aggregates of β-particles. Free β-particles are also present in liver, and are the only type of particle seen in skeletal muscle. They have diameters from 20 to 50 nm. We discuss the number distributions of glycogen particle diameters and the implications for the structure-function relationship of glycogens in these tissues. We point out the possible implications for the study of glycogen storage diseases, and of non-insulin dependent diabetes mellitus.
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Affiliation(s)
- Quinn A Besford
- School of Chemistry, University of Melbourne, Victoria 3010, Australia
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Hughey CC, Johnsen VL, Ma L, James FD, Young PP, Wasserman DH, Rottman JN, Hittel DS, Shearer J. Mesenchymal stem cell transplantation for the infarcted heart: a role in minimizing abnormalities in cardiac-specific energy metabolism. Am J Physiol Endocrinol Metab 2012; 302:E163-72. [PMID: 21971524 PMCID: PMC3340898 DOI: 10.1152/ajpendo.00443.2011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Intense interest has been focused on cell-based therapy for the infarcted heart given that stem cells have exhibited the ability to reduce infarct size and mitigate cardiac dysfunction. Despite this, it is unknown whether mesenchymal stem cell (MSC) therapy can prevent metabolic remodeling following a myocardial infarction (MI). This study examines the ability of MSCs to rescue the infarcted heart from perturbed substrate uptake in vivo. C57BL/6 mice underwent chronic ligation of the left anterior descending coronary artery to induce a MI. Echocardiography was performed on conscious mice at baseline as well as 7 and 23 days post-MI. Twenty-eight days following the ligation procedure, hyperinsulinemic euglycemic clamps assessed in vivo insulin sensitivity. Isotopic tracer administration evaluated whole body, peripheral tissue, and cardiac-specific glucose and fatty acid utilization. To gain insight into the mechanisms by which MSCs modulate metabolism, mitochondrial function was assessed by high-resolution respirometry using permeabilized cardiac fibers. Data show that MSC transplantation preserves insulin-stimulated fatty acid uptake in the peri-infarct region (4.25 ± 0.64 vs. 2.57 ± 0.34 vs. 3.89 ± 0.54 μmol·100 g(-1)·min(-1), SHAM vs. MI + PBS vs. MI + MSC; P < 0.05) and prevents increases in glucose uptake in the remote left ventricle (3.11 ± 0.43 vs. 3.81 ± 0.79 vs. 6.36 ± 1.08 μmol·100 g(-1)·min(-1), SHAM vs. MI + PBS vs. MI + MSC; P < 0.05). This was associated with an enhanced efficiency of mitochondrial oxidative phosphorylation with a respiratory control ratio of 3.36 ± 0.18 in MSC-treated cardiac fibers vs. 2.57 ± 0.14 in the infarct-only fibers (P < 0.05). In conclusion, MSC therapy exhibits the potential to rescue the heart from metabolic aberrations following a MI. Restoration of metabolic flexibility is important given the metabolic demands of the heart and the role of energetics in the progression to heart failure.
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Affiliation(s)
- Curtis C Hughey
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, 2500 University Dr. NW, Calgary, Alberta, Canada.
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