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Ye W, Han K, Xie M, Li S, Chen G, Wang Y, Li T. Mitochondrial energy metabolism in diabetic cardiomyopathy: Physiological adaption, pathogenesis, and therapeutic targets. Chin Med J (Engl) 2024; 137:936-948. [PMID: 38527931 PMCID: PMC11046025 DOI: 10.1097/cm9.0000000000003075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Indexed: 03/27/2024] Open
Abstract
ABSTRACT Diabetic cardiomyopathy is defined as abnormal structure and function of the heart in the setting of diabetes, which could eventually develop heart failure and leads to the death of the patients. Although blood glucose control and medications to heart failure show beneficial effects on this disease, there is currently no specific treatment for diabetic cardiomyopathy. Over the past few decades, the pathophysiology of diabetic cardiomyopathy has been extensively studied, and an increasing number of studies pinpoint that impaired mitochondrial energy metabolism is a key mediator as well as a therapeutic target. In this review, we summarize the latest research in the field of diabetic cardiomyopathy, focusing on mitochondrial damage and adaptation, altered energy substrates, and potential therapeutic targets. A better understanding of the mitochondrial energy metabolism in diabetic cardiomyopathy may help to gain more mechanistic insights and generate more precise mitochondria-oriented therapies to treat this disease.
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Affiliation(s)
- Wanlin Ye
- Department of Anesthesiology, Laboratory of Mitochondria and Metabolism, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Kun Han
- Department of Anesthesiology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, Sichuan 610041, China
| | - Maodi Xie
- Department of Anesthesiology, Laboratory of Mitochondria and Metabolism, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Sheyu Li
- Department of Endocrinology and Metabolism, Division of Guideline and Rapid Recommendation, Cochrane China Center, MAGIC China Center, Chinese Evidence-Based Medicine Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Guo Chen
- Department of Anesthesiology, Laboratory of Mitochondria and Metabolism, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Yanyan Wang
- Nursing Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Tao Li
- Department of Anesthesiology, Laboratory of Mitochondria and Metabolism, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
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Liu Y, Huo JL, Ren K, Pan S, Liu H, Zheng Y, Chen J, Qiao Y, Yang Y, Feng Q. Mitochondria-associated endoplasmic reticulum membrane (MAM): a dark horse for diabetic cardiomyopathy treatment. Cell Death Discov 2024; 10:148. [PMID: 38509100 PMCID: PMC10954771 DOI: 10.1038/s41420-024-01918-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 02/25/2024] [Accepted: 03/14/2024] [Indexed: 03/22/2024] Open
Abstract
Diabetic cardiomyopathy (DCM), an important complication of diabetes mellitus (DM), is one of the most serious chronic heart diseases and has become a major cause of heart failure worldwide. At present, the pathogenesis of DCM is unclear, and there is still a lack of effective therapeutics. Previous studies have shown that the homeostasis of mitochondria and the endoplasmic reticulum (ER) play a core role in maintaining cardiovascular function, and structural and functional abnormalities in these organelles seriously impact the occurrence and development of various cardiovascular diseases, including DCM. The interplay between mitochondria and the ER is mediated by the mitochondria-associated ER membrane (MAM), which participates in regulating energy metabolism, calcium homeostasis, mitochondrial dynamics, autophagy, ER stress, inflammation, and other cellular processes. Recent studies have proven that MAM is closely related to the initiation and progression of DCM. In this study, we aim to summarize the recent research progress on MAM, elaborate on the key role of MAM in DCM, and discuss the potential of MAM as an important therapeutic target for DCM, thereby providing a theoretical reference for basic and clinical studies of DCM treatment.
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Affiliation(s)
- Yong Liu
- Research Institute of Nephrology, Zhengzhou University, the First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, P. R. China
- Traditional Chinese Medicine Integrated Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, P. R. China
- Henan Province Research Center for Kidney Disease, 450052, Zhengzhou, P. R. China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, 450052, Zhengzhou, P. R. China
| | - Jin-Ling Huo
- Research Institute of Nephrology, Zhengzhou University, the First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, P. R. China
- Traditional Chinese Medicine Integrated Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, P. R. China
- Henan Province Research Center for Kidney Disease, 450052, Zhengzhou, P. R. China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, 450052, Zhengzhou, P. R. China
| | - Kaidi Ren
- Department of Pharmacy, the First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, P. R. China
| | - Shaokang Pan
- Research Institute of Nephrology, Zhengzhou University, the First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, P. R. China
- Traditional Chinese Medicine Integrated Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, P. R. China
- Henan Province Research Center for Kidney Disease, 450052, Zhengzhou, P. R. China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, 450052, Zhengzhou, P. R. China
| | - Hengdao Liu
- Department of Cardiology, the First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, P. R. China
| | - Yifeng Zheng
- Institute for Biomedical Sciences, Shinshu University, 8304 Minamiminowa, Kamiina, Nagano, 399-4598, Japan
| | - Jingfang Chen
- Research Institute of Nephrology, Zhengzhou University, the First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, P. R. China
- Traditional Chinese Medicine Integrated Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, P. R. China
- Henan Province Research Center for Kidney Disease, 450052, Zhengzhou, P. R. China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, 450052, Zhengzhou, P. R. China
| | - Yingjin Qiao
- Blood Purification Center, the First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, P. R. China.
| | - Yang Yang
- Clinical Systems Biology Research Laboratories, Translational Medicine Center, the First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, P. R. China.
| | - Qi Feng
- Research Institute of Nephrology, Zhengzhou University, the First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, P. R. China.
- Traditional Chinese Medicine Integrated Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, P. R. China.
- Henan Province Research Center for Kidney Disease, 450052, Zhengzhou, P. R. China.
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, 450052, Zhengzhou, P. R. China.
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Michaeli L, Spector E, Haeussler S, Carvalho CA, Grobe H, Abu-Shach UB, Zinger H, Conradt B, Broday L. ULP-2 SUMO protease regulates UPR mt and mitochondrial homeostasis in Caenorhabditis elegans. Free Radic Biol Med 2024; 214:19-27. [PMID: 38301974 PMCID: PMC10929073 DOI: 10.1016/j.freeradbiomed.2024.01.050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/19/2024] [Accepted: 01/29/2024] [Indexed: 02/03/2024]
Abstract
Mitochondria are the powerhouses of cells, responsible for energy production and regulation of cellular homeostasis. When mitochondrial function is impaired, a stress response termed mitochondrial unfolded protein response (UPRmt) is initiated to restore mitochondrial function. Since mitochondria and UPRmt are implicated in many diseases, it is important to understand UPRmt regulation. In this study, we show that the SUMO protease ULP-2 has a key role in regulating mitochondrial function and UPRmt. Specifically, down-regulation of ulp-2 suppresses UPRmt and reduces mitochondrial membrane potential without significantly affecting cellular ROS. Mitochondrial networks are expanded in ulp-2 null mutants with larger mitochondrial area and increased branching. Moreover, the amount of mitochondrial DNA is increased in ulp-2 mutants. Downregulation of ULP-2 also leads to alterations in expression levels of mitochondrial genes involved in protein import and mtDNA replication, however, mitophagy remains unaltered. In summary, this study demonstrates that ULP-2 is required for mitochondrial homeostasis and the UPRmt.
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Affiliation(s)
- Lirin Michaeli
- Department of Cell and Developmental Biology, School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Eyal Spector
- Department of Cell and Developmental Biology, School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Simon Haeussler
- Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Cátia A Carvalho
- Department of Cell and Developmental Biology, School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Hanna Grobe
- Department of Cell and Developmental Biology, School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Ulrike Bening Abu-Shach
- Department of Cell and Developmental Biology, School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Hen Zinger
- Department of Cell and Developmental Biology, School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Barbara Conradt
- Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany; Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Limor Broday
- Department of Cell and Developmental Biology, School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel.
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Jin Z, Ji Y, Su W, Zhou L, Wu X, Gao L, Guo J, Liu Y, Zhang Y, Wen X, Xia ZY, Xia Z, Lei S. The role of circadian clock-controlled mitochondrial dynamics in diabetic cardiomyopathy. Front Immunol 2023; 14:1142512. [PMID: 37215098 PMCID: PMC10196400 DOI: 10.3389/fimmu.2023.1142512] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 04/24/2023] [Indexed: 05/24/2023] Open
Abstract
Diabetes mellitus is a metabolic disease with a high prevalence worldwide, and cardiovascular complications are the leading cause of mortality in patients with diabetes. Diabetic cardiomyopathy (DCM), which is prone to heart failure with preserved ejection fraction, is defined as a cardiac dysfunction without conventional cardiac risk factors such as coronary heart disease and hypertension. Mitochondria are the centers of energy metabolism that are very important for maintaining the function of the heart. They are highly dynamic in response to environmental changes through mitochondrial dynamics. The disruption of mitochondrial dynamics is closely related to the occurrence and development of DCM. Mitochondrial dynamics are controlled by circadian clock and show oscillation rhythm. This rhythm enables mitochondria to respond to changing energy demands in different environments, but it is disordered in diabetes. In this review, we summarize the significant role of circadian clock-controlled mitochondrial dynamics in the etiology of DCM and hope to play a certain enlightening role in the treatment of DCM.
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Affiliation(s)
- Zhenshuai Jin
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yanwei Ji
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Wating Su
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Lu Zhou
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xiaojing Wu
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Lei Gao
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Junfan Guo
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yutong Liu
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yuefu Zhang
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xinyu Wen
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zhong-Yuan Xia
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zhengyuan Xia
- Department of Anesthesiology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
- Faculty of Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macao SAR, China
| | - Shaoqing Lei
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
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Khadangi A, Boudier T, Hanssen E, Rajagopal V. CardioVinci: building blocks for virtual cardiac cells using deep learning. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210469. [PMID: 36189496 PMCID: PMC9527637 DOI: 10.1098/rstb.2021.0469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Advances in electron microscopy (EM) such as electron tomography and focused ion-beam scanning electron microscopy provide unprecedented, three-dimensional views of cardiac ultrastructures within sample volumes ranging from hundreds of nanometres to hundreds of micrometres. The datasets from these samples are typically large, with file sizes ranging from gigabytes to terabytes and the number of image slices within the three-dimensional stack in the hundreds. A significant bottleneck with these large datasets is the time taken to extract and statistically analyse three-dimensional changes in cardiac ultrastructures. This is because of the inherently low contrast and the significant amount of structural detail that is present in EM images. These datasets often require manual annotation, which needs substantial person-hours and may result in only partial segmentation that makes quantitative analysis of the three-dimensional volumes infeasible. We present CardioVinci, a deep learning workflow to automatically segment and statistically quantify the morphologies and spatial assembly of mitochondria, myofibrils and Z-discs with minimal manual annotation. The workflow encodes a probabilistic model of the three-dimensional cardiomyocyte using a generative adversarial network. This generative model can be used to create new models of cardiomyocyte architecture that reflect variations in morphologies and cell architecture found in EM datasets. This article is part of the theme issue ‘The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease’.
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Affiliation(s)
- Afshin Khadangi
- Department of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Melbourne, Parkville, Australia
| | - Thomas Boudier
- Institut de Biologie Paris-Seine, Sorbonne Université Campus Pierre et Marie Curie, Paris, France
| | - Eric Hanssen
- Ian Holmes Imaging Center, Bio21, University of Melbourne, Parkville, Victoria, Australia
| | - Vijay Rajagopal
- Department of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Melbourne, Parkville, Australia
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Ghosh S, Guglielmi G, Orfanidis I, Spill F, Hickey A, Hanssen E, Rajagopal V. Effects of altered cellular ultrastructure on energy metabolism in diabetic cardiomyopathy: an in silico study. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210323. [PMID: 36189807 PMCID: PMC9527921 DOI: 10.1098/rstb.2021.0323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 03/09/2022] [Indexed: 11/12/2022] Open
Abstract
Diabetic cardiomyopathy is a leading cause of heart failure in diabetes. At the cellular level, diabetic cardiomyopathy leads to altered mitochondrial energy metabolism and cardiomyocyte ultrastructure. We combined electron microscopy (EM) and computational modelling to understand the impact of diabetes-induced ultrastructural changes on cardiac bioenergetics. We collected transverse micrographs of multiple control and type I diabetic rat cardiomyocytes using EM. Micrographs were converted to finite-element meshes, and bioenergetics was simulated over them using a biophysical model. The simulations also incorporated depressed mitochondrial capacity for oxidative phosphorylation (OXPHOS) and creatine kinase (CK) reactions to simulate diabetes-induced mitochondrial dysfunction. Analysis of micrographs revealed a 14% decline in mitochondrial area fraction in diabetic cardiomyocytes, and an irregular arrangement of mitochondria and myofibrils. Simulations predicted that this irregular arrangement, coupled with the depressed activity of mitochondrial CK enzymes, leads to large spatial variation in adenosine diphosphate (ADP)/adenosine triphosphate (ATP) ratio profile of diabetic cardiomyocytes. However, when spatially averaged, myofibrillar ADP/ATP ratios of a cardiomyocyte do not change with diabetes. Instead, average concentration of inorganic phosphate rises by 40% owing to lower mitochondrial area fraction and dysfunction in OXPHOS. These simulations indicate that a disorganized cellular ultrastructure negatively impacts metabolite transport in diabetic cardiomyopathy. This article is part of the theme issue 'The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease'.
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Affiliation(s)
- Shouryadipta Ghosh
- CSIRO Data61, Commonwealth Scientific and Industrial Research Organisation, Research Way, Clayton, VIC 3168, Australia
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC 3010, Australia
| | - Giovanni Guglielmi
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC 3010, Australia
- School of Mathematics, University of Birmingham, Edgbaston B15 2TS, UK
| | - Ioannis Orfanidis
- Health Data Specialists, Grand Canal Docklands, Dublin D02 VK08, Republic of Ireland
| | - Fabian Spill
- School of Mathematics, University of Birmingham, Edgbaston B15 2TS, UK
| | - Anthony Hickey
- School of Biological Sciences, University of Auckland, Auckland, NZ 1042, New Zealand
| | - Eric Hanssen
- Ian Holmes Imaging Center and Department of Biochemistry and Pharmacology, Bio21 Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Vijay Rajagopal
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC 3010, Australia
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Rajagopal V, Arumugam S, Hunter PJ, Khadangi A, Chung J, Pan M. The Cell Physiome: What Do We Need in a Computational Physiology Framework for Predicting Single-Cell Biology? Annu Rev Biomed Data Sci 2022; 5:341-366. [PMID: 35576556 DOI: 10.1146/annurev-biodatasci-072018-021246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Modern biology and biomedicine are undergoing a big data explosion, needing advanced computational algorithms to extract mechanistic insights on the physiological state of living cells. We present the motivation for the Cell Physiome project: a framework and approach for creating, sharing, and using biophysics-based computational models of single-cell physiology. Using examples in calcium signaling, bioenergetics, and endosomal trafficking, we highlight the need for spatially detailed, biophysics-based computational models to uncover new mechanisms underlying cell biology. We review progress and challenges to date toward creating cell physiome models. We then introduce bond graphs as an efficient way to create cell physiome models that integrate chemical, mechanical, electromagnetic, and thermal processes while maintaining mass and energy balance. Bond graphs enhance modularization and reusability of computational models of cells at scale. We conclude with a look forward at steps that will help fully realize this exciting new field of mechanistic biomedical data science. Expected final online publication date for the Annual Review of Biomedical Data Science, Volume 5 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Vijay Rajagopal
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria, Australia;
| | - Senthil Arumugam
- Cellular Physiology Lab, Monash Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences; European Molecular Biological Laboratory (EMBL) Australia; and Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton/Melbourne, Victoria, Australia
| | - Peter J Hunter
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Afshin Khadangi
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria, Australia;
| | - Joshua Chung
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria, Australia;
| | - Michael Pan
- School of Mathematics and Statistics, University of Melbourne, Melbourne, Victoria, Australia
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Seyydi SM, Tofighi A, Rahmati M, Tolouei Azar J. Exercise and Urtica Dioica extract ameliorate mitochondrial function and the expression of cardiac muscle Nuclear Respiratory Factor 2 and Peroxisome proliferator-activated receptor Gamma Coactivator 1-alpha in STZ-induced diabetic rats. Gene 2022; 822:146351. [PMID: 35189251 DOI: 10.1016/j.gene.2022.146351] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/30/2022] [Accepted: 02/15/2022] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Diabetes mellitus can affect and disrupt the levels of PGC1α and NRF2 proteins in the mitochondrial biogenesis pathway. Considering the anti-diabetic properties of Urtica Dioica extract and exercise, this study aimed to investigate the beneficial effects of Urtica Dioica extract and endurance activity on PGC1α and NRF2 protein levels in the streptozotocin-induced diabetic rat heart tissue. MATERIALS AND METHODS 58 male Wistar rats were divided into five groups (N = 12) including: healthy control (HC), diabetes control (DC), diabetes Urtica Dioica (D-UD), diabetes exercise training (DT), and diabetes exercise training Urtica Dioica (DT-UD). Diabetes was induced intraperitoneally by STZ (45 mg/kg) injection. Two weeks after the induction of diabetes, the rats were stimulated to carry out the exercise (moderate intensity/5day/week) and the gavage of UD extract (50 mg/kg/day) was administered to the rats for six weeks. In this study, the western blotting method was used to measure the levels of PGC1α and NRF2 proteins. Moreover, cardiography was used to evaluate the functional parameters of the heart (ejection fraction & fractional shortening). Finally, the bioluminescence and ELISA methods were used to determine the content of adenosine triphosphate and citrate synthase. RESULTS The cardiac function parameters, the mitochondrial ATP and the CS content in DC group mice were impaired in comparison with the other study groups and showed a decreasing trend (P < 0.001). The treatment with EX + UD extract was able to minimize the rate of these disorders and acted as a protector of mitochondrial function. There were significant differences in the expression levels of NRF2 (F = 17.7, P = 0.001) and PGC-1α (F = 43.7, P = 0.001) mitochondrial proteins among the different groups. The levels of these proteins were significantly reduced in the DC group in comparison with the HC group (P < 0.001). The treatment with EX or UD extract increased the expression of PGC-1α and NRF2 proteins in the heart muscle of animals in the DT and D-UD groups in comparison with the DC group (P < 0.05). Moreover, the expression of these proteins was more pronounced in the DT-UD group. There was not a significant difference between the DT-UD group and the HC group regarding the expression of these proteins (P > 0.05). CONCLUSIONS The results of this study showed that treatment with EX and UD extract could treat the disorders which were caused by diabetes in the parameters of cardiac function. Moreover, it was able to improve the expression of the levels of proteins which were involved in mitochondrial biogenesis and its function. Finally, this kind of treatment could attract more attention to the roles of EX and UD extract in the prevention of cardiovascular complications in future studies.
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Affiliation(s)
- Seyyedeh Masoumeh Seyydi
- Department of Exercise Physiology and Corrective Movements, Faculty of Sports Sciences, Urmia University, Urmia, Iran
| | - Asghar Tofighi
- Department of Exercise Physiology and Corrective Movements, Faculty of Sports Sciences, Urmia University, Urmia, Iran.
| | - Masoud Rahmati
- Department of Physical Education and Sport Sciences, Faculty of Literature and Human Sciences, Lorestan University, Khorramabad, Iran
| | - Javad Tolouei Azar
- Department of Exercise Physiology and Corrective Movements, Faculty of Sports Sciences, Urmia University, Urmia, Iran
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LXR activation ameliorates high glucose stress-induced aberrant mitochondrial dynamics via downregulation of Calpain1 expression in H9c2 cardiomyoblasts. Biochem Biophys Res Commun 2022; 614:145-152. [PMID: 35597151 DOI: 10.1016/j.bbrc.2022.05.025] [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: 03/18/2022] [Revised: 05/07/2022] [Accepted: 05/09/2022] [Indexed: 11/22/2022]
Abstract
Liver-X-receptor (LXR) has previously been shown to exert a cardioprotective effect against the development of diabetic cardiomyopathy (DCM) associated with a reduction in mitochondrial dysfunction. However, the underlying mechanism by which LXR activation attenuates the structural and functional mitochondrial impairments caused by high glucose (HG) stress remains unclear. We demonstrate here that LXR activation inhibits HG stress-induced mitochondrial dysfunction and ameliorates aberrant mitochondrial dynamics. Furthermore, LXR activation regulates mitochondrial dynamics by inhibiting HG stress-induced upregulation of Calpain1 expression. These data indicate that amelioration of Calpain1-mediated aberrant mitochondrial dynamics may be at least part of the mechanism underlying the cardioprotective effects of LXR against HG stress. Therefore, LXR is a potentially attractive molecular target for treating cardiac mitochondrial dysfunction in patients with diabetes.
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10
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Fei J, Demillard LJ, Ren J. Reactive oxygen species in cardiovascular diseases: an update. EXPLORATION OF MEDICINE 2022. [DOI: 10.37349/emed.2022.00085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Cardiovascular diseases are among the leading causes of death worldwide, imposing major health threats. Reactive oxygen species (ROS) are one of the most important products from the process of redox reactions. In the onset and progression of cardiovascular diseases, ROS are believed to heavily influence homeostasis of lipids, proteins, DNA, mitochondria, and energy metabolism. As ROS production increases, the heart is damaged, leading to further production of ROS. The vicious cycle continues on as additional ROS are generated. For example, recent evidence indicated that connexin 43 (Cx43) deficiency and pyruvate kinase M2 (PKM2) activation led to a loss of protection in cardiomyocytes. In this context, a better understanding of the mechanisms behind ROS production is vital in determining effective treatment and management strategies for cardiovascular diseases.
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Affiliation(s)
- Juanjuan Fei
- Department of Cardiology, Zhongshan Hospital Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai 200032, China
| | - Laurie J. Demillard
- School of Pharmacy, University of Wyoming College of Health Sciences, Laramie, WY 82071, USA
| | - Jun Ren
- Department of Cardiology, Zhongshan Hospital Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai 200032, China; Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
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Lipotoxicity-induced mtDNA release promotes diabetic cardiomyopathy by activating the cGAS-STING pathway in obesity-related diabetes. Cell Biol Toxicol 2022; 39:277-299. [PMID: 35235096 PMCID: PMC10042943 DOI: 10.1007/s10565-021-09692-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 12/22/2021] [Indexed: 11/02/2022]
Abstract
Diabetic cardiomyopathy (DCM) is characterized by lipid accumulation, mitochondrial dysfunction, and aseptic inflammatory activation. Mitochondria-derived cytosolic DNA has been reported to induce inflammation by activating cyclic GMP-AMP synthase (cGAS)/the stimulator of interferon genes (STING) pathway in the adipose, liver, and kidney tissues. However, the role of cytosolic mtDNA in the progression of DCM is unclear. In this study, with an obesity-related DCM mouse model established by feeding db/db mice with a high-fat diet (HFD), we observed increased mtDNA in the cytosol and activated cGAS-STING signaling pathway during DCM, as well as the downstream targets, IRF3, NF-κB, IL-18, and IL-1β. In a further study with a palmitic acid (PA)-induced lipotoxic cell model established in H9C2 cells, we revealed that the cytosolic mtDNA was the result of PA-induced overproduction of mitochondrial ROS, which also led to the activation of the cGAS/STING system and its downstream targets. Notably, treatment of extracted mtDNA alone was sufficient to activate the cGAS-STING signaling pathway in cultured H9C2 cells. Besides, both knockdown of STING in PA-induced H9C2 cells and inhibition of STING by C-176 injection in the DCM mouse model could remarkably block the inflammation and apoptosis of cardiomyocytes. In conclusion, our study elucidated the critical role of cytosolic mtDNA-induced cGAS-STING activation in the pathogenesis of obesity-related DCM and provided preclinical validation for using a STING inhibitor as a new potential therapeutic strategy for the treatment of DCM.
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12
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Time-of-Day Circadian Modulation of Grape-Seed Procyanidin Extract (GSPE) in Hepatic Mitochondrial Dynamics in Cafeteria-Diet-Induced Obese Rats. Nutrients 2022; 14:nu14040774. [PMID: 35215423 PMCID: PMC8876123 DOI: 10.3390/nu14040774] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 02/04/2022] [Accepted: 02/08/2022] [Indexed: 12/13/2022] Open
Abstract
Major susceptibility to alterations in liver function (e.g., hepatic steatosis) in a prone environment due to circadian misalignments represents a common consequence of recent sociobiological behavior (i.e., food excess and sleep deprivation). Natural compounds and, more concisely, polyphenols have been shown as an interesting tool for fighting against metabolic syndrome and related consequences. Furthermore, mitochondria have been identified as an important target for mediation of the health effects of these compounds. Additionally, mitochondrial function and dynamics are strongly regulated in a circadian way. Thus, we wondered whether some of the beneficial effects of grape-seed procyanidin extract (GSPE) on metabolic syndrome could be mediated by a circadian modulation of mitochondrial homeostasis. For this purpose, rats were subjected to “standard”, “cafeteria” and “cafeteria diet + GSPE” treatments (n = 4/group) for 9 weeks (the last 4 weeks, GSPE/vehicle) of treatment, administering the extract/vehicle at diurnal or nocturnal times (ZT0 or ZT12). For circadian assessment, one hour after turning the light on (ZT1), animals were sacrificed every 6 h (ZT1, ZT7, ZT13 and ZT19). Interestingly, GSPE was able to restore the rhythm on clock hepatic genes (Bmal1, Per2, Cry1, Rorα), as this correction was more evident in nocturnal treatment. Additionally, during nocturnal treatment, an increase in hepatic fusion genes and a decrease in fission genes were observed. Regarding mitochondrial complex activity, there was a strong effect of cafeteria diet at nearly all ZTs, and GSPE was able to restore activity at discrete ZTs, mainly in the diurnal treatment (ZT0). Furthermore, a differential behavior was observed in tricarboxylic acid (TCA) metabolites between GSPE diurnal and nocturnal administration times. Therefore, GSPE may serve as a nutritional preventive strategy in the recovery of hepatic-related metabolic disease by modulating mitochondrial dynamics, which is concomitant to the restoration of the hepatic circadian machinery.
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13
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Sapian S, Taib IS, Latip J, Katas H, Chin KY, Mohd Nor NA, Jubaidi FF, Budin SB. Therapeutic Approach of Flavonoid in Ameliorating Diabetic Cardiomyopathy by Targeting Mitochondrial-Induced Oxidative Stress. Int J Mol Sci 2021; 22:11616. [PMID: 34769045 PMCID: PMC8583796 DOI: 10.3390/ijms222111616] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 12/26/2022] Open
Abstract
Diabetes cardiomyopathy is one of the key factors of mortality among diabetic patients around the globe. One of the prior contributors to the progression of diabetic cardiomyopathy is cardiac mitochondrial dysfunction. The cardiac mitochondrial dysfunction can induce oxidative stress in cardiomyocytes and was found to be the cause of majority of the heart morphological and dynamical changes in diabetic cardiomyopathy. To slow down the occurrence of diabetic cardiomyopathy, it is crucial to discover therapeutic agents that target mitochondrial-induced oxidative stress. Flavonoid is a plentiful phytochemical in plants that shows a wide range of biological actions against human diseases. Flavonoids have been extensively documented for their ability to protect the heart from diabetic cardiomyopathy. Flavonoids' ability to alleviate diabetic cardiomyopathy is primarily attributed to their antioxidant properties. In this review, we present the mechanisms involved in flavonoid therapies in ameliorating mitochondrial-induced oxidative stress in diabetic cardiomyopathy.
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Affiliation(s)
- Syaifuzah Sapian
- Centre for Diagnostic, Therapeutic and Investigative Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia; (S.S.); (I.S.T.); (N.A.M.N.); (F.F.J.)
| | - Izatus Shima Taib
- Centre for Diagnostic, Therapeutic and Investigative Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia; (S.S.); (I.S.T.); (N.A.M.N.); (F.F.J.)
| | - Jalifah Latip
- School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 46300, Malaysia;
| | - Haliza Katas
- Centre for Drug Delivery Research, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia;
| | - Kok-Yong Chin
- Department of Pharmacology, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur 56000, Malaysia;
| | - Nor Anizah Mohd Nor
- Centre for Diagnostic, Therapeutic and Investigative Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia; (S.S.); (I.S.T.); (N.A.M.N.); (F.F.J.)
| | - Fatin Farhana Jubaidi
- Centre for Diagnostic, Therapeutic and Investigative Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia; (S.S.); (I.S.T.); (N.A.M.N.); (F.F.J.)
| | - Siti Balkis Budin
- Centre for Diagnostic, Therapeutic and Investigative Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia; (S.S.); (I.S.T.); (N.A.M.N.); (F.F.J.)
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14
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Heinen-Weiler J, Hasenberg M, Heisler M, Settelmeier S, Beerlage AL, Doepper H, Walkenfort B, Odersky A, Luedike P, Winterhager E, Rassaf T, Hendgen-Cotta UB. Superiority of focused ion beam-scanning electron microscope tomography of cardiomyocytes over standard 2D analyses highlighted by unmasking mitochondrial heterogeneity. J Cachexia Sarcopenia Muscle 2021; 12:933-954. [PMID: 34120411 PMCID: PMC8350221 DOI: 10.1002/jcsm.12742] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 04/16/2021] [Accepted: 05/21/2021] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Cardioprotection by preventing or repairing mitochondrial damage is an unmet therapeutic need. To understand the role of cardiomyocyte mitochondria in physiopathology, the reliable characterization of the mitochondrial morphology and compartment is pivotal. Previous studies mostly relied on two-dimensional (2D) routine transmission electron microscopy (TEM), thereby neglecting the real three-dimensional (3D) mitochondrial organization. This study aimed to determine whether classical 2D TEM analysis of the cardiomyocyte ultrastructure is sufficient to comprehensively describe the mitochondrial compartment and to reflect mitochondrial number, size, dispersion, distribution, and morphology. METHODS Spatial distribution of the complex mitochondrial network and morphology, number, and size heterogeneity of cardiac mitochondria in isolated adult mouse cardiomyocytes and adult wild-type left ventricular tissues (C57BL/6) were assessed using a comparative 3D imaging system based on focused ion beam-scanning electron microscopy (FIB-SEM) nanotomography. For comparison of 2D vs. 3D data sets, analytical strategies and mathematical comparative approaches were performed. To confirm the value of 3D data for mitochondrial changes, we compared the obtained values for number, coverage area, size heterogeneity, and complexity of wild-type cardiomyocyte mitochondria with data sets from mice lacking the cytosolic and mitochondrial protein BNIP3 (BCL-2/adenovirus E1B 19-kDa interacting protein 3; Bnip3-/- ) using FIB-SEM. Mitochondrial respiration was assessed on isolated mitochondria using the Seahorse XF analyser. A cardiac biopsy was obtained from a male patient (48 years) suffering from myocarditis. RESULTS The FIB-SEM nanotomographic analysis revealed that no linear relationship exists for mitochondrial number (r = 0.02; P = 0.9511), dispersion (r = -0.03; P = 0.9188), and shape (roundness: r = 0.15, P = 0.6397; elongation: r = -0.09, P = 0.7804) between 3D and 2D results. Cumulative frequency distribution analysis showed a diverse abundance of mitochondria with different sizes in 3D and 2D. Qualitatively, 2D data could not reflect mitochondrial distribution and dynamics existing in 3D tissue. 3D analyses enabled the discovery that BNIP3 deletion resulted in more smaller, less complex cardiomyocyte mitochondria (number: P < 0.01; heterogeneity: C.V. wild-type 89% vs. Bnip3-/- 68%; complexity: P < 0.001) forming large myofibril-distorting clusters, as seen in human myocarditis with disturbed mitochondrial dynamics. Bnip3-/- mice also show a higher respiration rate (P < 0.01). CONCLUSIONS Here, we demonstrate the need of 3D analyses for the characterization of mitochondrial features in cardiac tissue samples. Hence, we observed that BNIP3 deletion physiologically acts as a molecular brake on mitochondrial number, suggesting a role in mitochondrial fusion/fission processes and thereby regulating the homeostasis of cardiac bioenergetics.
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Affiliation(s)
- Jacqueline Heinen-Weiler
- Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center, Medical Faculty, University of Duisburg-Essen, Essen, Germany.,Imaging Center Essen (IMCES), Electron Microscopy Unit (EMU), Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Mike Hasenberg
- Imaging Center Essen (IMCES), Electron Microscopy Unit (EMU), Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Martin Heisler
- Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center, Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Stephan Settelmeier
- Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center, Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Anna-Lena Beerlage
- Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center, Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Hannah Doepper
- Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center, Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Bernd Walkenfort
- Imaging Center Essen (IMCES), Electron Microscopy Unit (EMU), Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Andrea Odersky
- Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center, Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Peter Luedike
- Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center, Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Elke Winterhager
- Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center, Medical Faculty, University of Duisburg-Essen, Essen, Germany.,Imaging Center Essen (IMCES), Electron Microscopy Unit (EMU), Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Tienush Rassaf
- Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center, Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Ulrike B Hendgen-Cotta
- Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center, Medical Faculty, University of Duisburg-Essen, Essen, Germany
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15
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Physically-plausible modelling of biomolecular systems: A simplified, energy-based model of the mitochondrial electron transport chain. J Theor Biol 2020; 493:110223. [PMID: 32119969 DOI: 10.1016/j.jtbi.2020.110223] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 01/21/2020] [Accepted: 02/27/2020] [Indexed: 11/20/2022]
Abstract
Advances in systems biology and whole-cell modelling demand increasingly comprehensive mathematical models of cellular biochemistry. Such models require the development of simplified representations of specific processes which capture essential biophysical features but without unnecessarily complexity. Recently there has been renewed interest in thermodynamically-based modelling of cellular processes. Here we present an approach to developing of simplified yet thermodynamically consistent (hence physically plausible) models which can readily be incorporated into large scale biochemical descriptions but which do not require full mechanistic detail of the underlying processes. We illustrate the approach through development of a simplified, physically plausible model of the mitochondrial electron transport chain and show that the simplified model behaves like the full system.
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16
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Kaludercic N, Di Lisa F. Mitochondrial ROS Formation in the Pathogenesis of Diabetic Cardiomyopathy. Front Cardiovasc Med 2020; 7:12. [PMID: 32133373 PMCID: PMC7040199 DOI: 10.3389/fcvm.2020.00012] [Citation(s) in RCA: 151] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/28/2020] [Indexed: 12/20/2022] Open
Abstract
Diabetic cardiomyopathy is a result of diabetes-induced changes in the structure and function of the heart. Hyperglycemia affects multiple pathways in the diabetic heart, but excessive reactive oxygen species (ROS) generation and oxidative stress represent common denominators associated with adverse tissue remodeling. Indeed, key processes underlying cardiac remodeling in diabetes are redox sensitive, including inflammation, organelle dysfunction, alteration in ion homeostasis, cardiomyocyte hypertrophy, apoptosis, fibrosis, and contractile dysfunction. Extensive experimental evidence supports the involvement of mitochondrial ROS formation in the alterations characterizing the diabetic heart. In this review we will outline the central role of mitochondrial ROS and alterations in the redox status contributing to the development of diabetic cardiomyopathy. We will discuss the role of different sources of ROS involved in this process, with a specific emphasis on mitochondrial ROS producing enzymes within cardiomyocytes. Finally, the therapeutic potential of pharmacological inhibitors of ROS sources within the mitochondria will be discussed.
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Affiliation(s)
- Nina Kaludercic
- Neuroscience Institute, National Research Council of Italy (CNR), Padua, Italy
| | - Fabio Di Lisa
- Neuroscience Institute, National Research Council of Italy (CNR), Padua, Italy.,Department of Biomedical Sciences, University of Padua, Padua, Italy
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17
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Myers MJ, Shepherd DL, Durr AJ, Stanton DS, Mohamed JS, Hollander JM, Alway SE. The role of SIRT1 in skeletal muscle function and repair of older mice. J Cachexia Sarcopenia Muscle 2019; 10:929-949. [PMID: 31197980 PMCID: PMC6711423 DOI: 10.1002/jcsm.12437] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 03/21/2019] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Sirtuin 1 (SIRT1) is a NAD+ sensitive deacetylase that has been linked to longevity and has been suggested to confer beneficial effects that counter aging-associated deterioration. Muscle repair is dependent upon satellite cell function, which is reported to be reduced with aging; however, it is not known if this is linked to an aging-suppression of SIRT1. This study tested the hypothesis that Sirtuin 1 (SIRT1) overexpression would increase the extent of muscle repair and muscle function in older mice. METHODS We examined satellite cell dependent repair in tibialis anterior, gastrocnemius, and soleus muscles of 13 young wild-type mice (20-30 weeks) and 49 older (80+ weeks) mice that were controls (n = 13), overexpressed SIRT1 in skeletal muscle (n = 14), and had a skeletal muscle SIRT1 knockout (n = 12) or a satellite cell SIRT1 knockout (n = 10). Acute muscle injury was induced by injection of cardiotoxin (CTX), and phosphate-buffered saline was used as a vector control. Plantarflexor muscle force and fatigue were evaluated before or 21 days after CTX injection. Satellite cell proliferation and mitochondrial function were also evaluated in undamaged muscles. RESULTS Maximal muscle force was significantly lower in control muscles of older satellite cell knockout SIRT1 mice compared to young adult wild-type (YWT) mice (P < 0.001). Mean contraction force at 40 Hz stimulation was significantly greater after recovery from CTX injury in older mice that overexpressed muscle SIRT1 than age-matched SIRT1 knockout mice (P < 0.05). SIRT1 muscle knockout models (P < 0.05) had greater levels of p53 (P < 0.05 MKO, P < 0.001 OE) in CTX-damaged tissues as compared to YWT CTX mice. SIRT1 overexpression with co-expression of p53 was associated with increased fatigue resistance and increased force potentiation during repeated contractions as compared to wild-type or SIRT1 knockout models (P < 0.001). Muscle structure and mitochondrial function were not different between the groups, but proliferation of satellite cells was significantly greater in older mice with SIRT1 muscle knockout (P < 0.05), but not older SIRT1 satellite cell knockout models, in vitro, although this effect was attenuated in vivo after 21 days of recovery. CONCLUSIONS The data suggest skeletal muscle structure, function, and recovery after CTX-induced injury are not significantly influenced by gain or loss of SIRT1 abundance alone in skeletal muscle; however, muscle function is impaired by ablation of SIRT1 in satellite cells. SIRT1 appears to interact with p53 to improve muscle fatigue resistance after repair from muscle injury.
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Affiliation(s)
- Matthew J. Myers
- Laboratory of Muscle Biology and SarcopeniaWest Virginia University School of MedicineMorgantownUSA
| | - Danielle L. Shepherd
- Division of Exercise Physiology and Center for Cardiovascular and Respiratory SciencesWest Virginia University School of MedicineMorgantownUSA
| | - Andrya J. Durr
- Division of Exercise Physiology and Center for Cardiovascular and Respiratory SciencesWest Virginia University School of MedicineMorgantownUSA
| | - David S. Stanton
- Laboratory of Muscle Biology and SarcopeniaWest Virginia University School of MedicineMorgantownUSA
| | - Junaith S. Mohamed
- Laboratory of Muscle Biology and SarcopeniaWest Virginia University School of MedicineMorgantownUSA
- Laboratory of Nerve and Muscle, Department of Clinical Laboratory Sciences, College of Health ProfessionsUniversity of Tennessee Health Science CenterMemphisUSA
| | - John M. Hollander
- Division of Exercise Physiology and Center for Cardiovascular and Respiratory SciencesWest Virginia University School of MedicineMorgantownUSA
| | - Stephen E. Alway
- Laboratory of Muscle Biology and SarcopeniaWest Virginia University School of MedicineMorgantownUSA
- Laboratory of Muscle Biology and Sarcopenia, Department of Physical Therapy, College of Health ProfessionsUniversity of Tennessee Health Science CenterMemphisUSA
- Department of Physiology, College of MedicineUniversity of Tennessee Health Science CenterMemphisUSA
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18
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Abstract
Significance: In addition to their classical role in cellular ATP production, mitochondria are of key relevance in various (patho)physiological mechanisms including second messenger signaling, neuro-transduction, immune responses and death induction. Recent Advances: Within cells, mitochondria are motile and display temporal changes in internal and external structure ("mitochondrial dynamics"). During the last decade, substantial empirical and in silico evidence was presented demonstrating that mitochondrial dynamics impacts on mitochondrial function and vice versa. Critical Issues: However, a comprehensive and quantitative understanding of the bidirectional links between mitochondrial external shape, internal structure and function ("morphofunction") is still lacking. The latter particularly hampers our understanding of the functional properties and behavior of individual mitochondrial within single living cells. Future Directions: In this review we discuss the concept of mitochondrial morphofunction in mammalian cells, primarily using experimental evidence obtained within the last decade. The topic is introduced by briefly presenting the central role of mitochondria in cell physiology and the importance of the mitochondrial electron transport chain (ETC) therein. Next, we summarize in detail how mitochondrial (ultra)structure is controlled and discuss empirical evidence regarding the equivalence of mitochondrial (ultra)structure and function. Finally, we provide a brief summary of how mitochondrial morphofunction can be quantified at the level of single cells and mitochondria, how mitochondrial ultrastructure/volume impacts on mitochondrial bioreactions and intramitochondrial protein diffusion, and how mitochondrial morphofunction can be targeted by small molecules.
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Affiliation(s)
- Elianne P. Bulthuis
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Merel J.W. Adjobo-Hermans
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Peter H.G.M. Willems
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Werner J.H. Koopman
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
- Address correspondence to: Dr. Werner J.H. Koopman, Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, P.O. Box 9101, Nijmegen NL-6500 HB, The Netherlands
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19
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Ghosh S, Tran K, Delbridge LMD, Hickey AJR, Hanssen E, Crampin EJ, Rajagopal V. Insights on the impact of mitochondrial organisation on bioenergetics in high-resolution computational models of cardiac cell architecture. PLoS Comput Biol 2018; 14:e1006640. [PMID: 30517098 PMCID: PMC6296675 DOI: 10.1371/journal.pcbi.1006640] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 12/17/2018] [Accepted: 11/13/2018] [Indexed: 01/05/2023] Open
Abstract
Recent electron microscopy data have revealed that cardiac mitochondria are not arranged in crystalline columns but are organised with several mitochondria aggregated into columns of varying sizes spanning the cell cross-section. This raises the question—how does the mitochondrial arrangement affect the metabolite distributions within cardiomyocytes and what is its impact on force dynamics? Here, we address this question by employing finite element modeling of cardiac bioenergetics on computational meshes derived from electron microscope images. Our results indicate that heterogeneous mitochondrial distributions can lead to significant spatial variation across the cell in concentrations of inorganic phosphate, creatine (Cr) and creatine phosphate (PCr). However, our model predicts that sufficient activity of the creatine kinase (CK) system, coupled with rapid diffusion of Cr and PCr, maintains near uniform ATP and ADP ratios across the cell cross sections. This homogenous distribution of ATP and ADP should also evenly distribute force production and twitch duration with contraction. These results suggest that the PCr shuttle and associated enzymatic reactions act to maintain uniform force dynamics in the cell despite the heterogeneous mitochondrial organization. However, our model also predicts that under hypoxia activity of mitochondrial CK enzymes and diffusion of high-energy phosphate compounds may be insufficient to sustain uniform ATP/ADP distribution and hence force generation. Mammalian cardiomyocytes contain a high volume of mitochondria, which maintains the continuous and bulk supply of ATP to sustain normal heart function. Previously, cardiac mitochondria were understood to be distributed in a regular, crystalline pattern, which facilitated a steady supply of ATP at different workloads. Using electron microscopy images of cell cross sections, we recently found that they are not regularly distributed inside cardiomyocytes. We created new spatially accurate computational models of cardiac cell bioenergetics and tested whether this heterogeneous distribution of mitochondria causes non-uniform energy supply and contractile force production in the cardiomyocyte. We found that ATP and ADP concentrations remain uniform throughout the cell because of the activity of creatine kinase (CK) enzymes that convert ATP produced in the mitochondria into creatine phosphate. Creatine phosphate rapidly diffuses to the myofibril region where it can be converted back to ATP for the contraction cycle in a timely manner. This mechanism is called the phosphocreatine shuttle (PCr shuttle). The PCr shuttle ensures that different areas of the cell produce the same amount of force regardless of the mitochondrial distribution. However, our model also shows that when the cellular oxygen supply is limited—as can be the case in conditions such as heart failure—the PCr shuttle cannot maintain uniform ATP and ADP concentrations across the cell. This causes a non-uniform acto-myosin force distribution and non-uniform twitch duration across the cell cross section. Our study suggests that mechanisms other than the PCr shuttle may be necessary to maintain uniform supply of ATP in a hypoxic environment.
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Affiliation(s)
- Shouryadipta Ghosh
- Cell Structure and Mechanobiology Group, Dept. of Biomedical Engineering, Melbourne School of Engineering, University of Melbourne, Melbourne, Australia
- Systems Biology Laboratory, School of Mathematics and Statistics, and Melbourne School of Engineering, University of Melbourne, Melbourne, Australia
| | - Kenneth Tran
- Auckland Bioengineering Institute, University of Auckland, Auckland New Zealand
| | | | | | - Eric Hanssen
- Advanced Microscopy Facility, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia
| | - Edmund J. Crampin
- Systems Biology Laboratory, School of Mathematics and Statistics, and Melbourne School of Engineering, University of Melbourne, Melbourne, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of Melbourne, Melbourne, Australia
| | - Vijay Rajagopal
- Cell Structure and Mechanobiology Group, Dept. of Biomedical Engineering, Melbourne School of Engineering, University of Melbourne, Melbourne, Australia
- * E-mail:
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20
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Wang Q, Lu W, Yang J, Jiang L, Zhang Q, Kan X, Yang X. Comparative transcriptomics in three Passerida species provides insights into the evolution of avian mitochondrial complex I. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2018; 28:27-36. [DOI: 10.1016/j.cbd.2018.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 06/04/2018] [Accepted: 06/13/2018] [Indexed: 02/02/2023]
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21
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Rajagopal V, Bass G, Ghosh S, Hunt H, Walker C, Hanssen E, Crampin E, Soeller C. Creating a Structurally Realistic Finite Element Geometric Model of a Cardiomyocyte to Study the Role of Cellular Architecture in Cardiomyocyte Systems Biology. J Vis Exp 2018. [PMID: 29733314 DOI: 10.3791/56817] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
With the advent of three-dimensional (3D) imaging technologies such as electron tomography, serial-block-face scanning electron microscopy and confocal microscopy, the scientific community has unprecedented access to large datasets at sub-micrometer resolution that characterize the architectural remodeling that accompanies changes in cardiomyocyte function in health and disease. However, these datasets have been under-utilized for investigating the role of cellular architecture remodeling in cardiomyocyte function. The purpose of this protocol is to outline how to create an accurate finite element model of a cardiomyocyte using high resolution electron microscopy and confocal microscopy images. A detailed and accurate model of cellular architecture has significant potential to provide new insights into cardiomyocyte biology, more than experiments alone can garner. The power of this method lies in its ability to computationally fuse information from two disparate imaging modalities of cardiomyocyte ultrastructure to develop one unified and detailed model of the cardiomyocyte. This protocol outlines steps to integrate electron tomography and confocal microscopy images of adult male Wistar (name for a specific breed of albino rat) rat cardiomyocytes to develop a half-sarcomere finite element model of the cardiomyocyte. The procedure generates a 3D finite element model that contains an accurate, high-resolution depiction (on the order of ~35 nm) of the distribution of mitochondria, myofibrils and ryanodine receptor clusters that release the necessary calcium for cardiomyocyte contraction from the sarcoplasmic reticular network (SR) into the myofibril and cytosolic compartment. The model generated here as an illustration does not incorporate details of the transverse-tubule architecture or the sarcoplasmic reticular network and is therefore a minimal model of the cardiomyocyte. Nevertheless, the model can already be applied in simulation-based investigations into the role of cell structure in calcium signaling and mitochondrial bioenergetics, which is illustrated and discussed using two case studies that are presented following the detailed protocol.
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Affiliation(s)
- Vijay Rajagopal
- Cell Structure and Mechanobiology Group, University of Melbourne; Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne; Department of Biomedical Engineering, University of Melbourne;
| | - Gregory Bass
- Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne; Department of Biomedical Engineering, University of Melbourne
| | - Shouryadipta Ghosh
- Cell Structure and Mechanobiology Group, University of Melbourne; Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne; Department of Biomedical Engineering, University of Melbourne
| | - Hilary Hunt
- Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne; School of Mathematics and Statistics, Faculty of Science, University of Melbourne
| | - Cameron Walker
- Department of Engineering Science, University of Auckland
| | - Eric Hanssen
- Advanced Microscopy Facility, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne
| | - Edmund Crampin
- Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne; Department of Biomedical Engineering, University of Melbourne; School of Mathematics and Statistics, Faculty of Science, University of Melbourne; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of Melbourne; School of Medicine, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne
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22
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An automated workflow for segmenting single adult cardiac cells from large-volume serial block-face scanning electron microscopy data. J Struct Biol 2018; 202:275-285. [PMID: 29477758 DOI: 10.1016/j.jsb.2018.02.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 01/03/2018] [Accepted: 02/20/2018] [Indexed: 11/20/2022]
Abstract
This paper presents a new algorithm to automatically segment the myofibrils, mitochondria and nuclei within single adult cardiac cells that are part of a large serial-block-face scanning electron microscopy (SBF-SEM) dataset. The algorithm only requires a set of manually drawn contours that roughly demarcate the cell boundary at routine slice intervals (every 50th, for example). The algorithm correctly classified pixels within the single cell with 97% accuracy when compared to manual segmentations. One entire cell and the partial volumes of two cells were segmented. Analysis of segmentations within these cells showed that myofibrils and mitochondria occupied 47.5% and 51.6% on average respectively, while the nuclei occupy 0.7% of the cell for which the entire volume was captured in the SBF-SEM dataset. Mitochondria clustering increased at the periphery of the nucleus region and branching points of the cardiac cell. The segmentations also showed high area fraction of mitochondria (up to 70% of the 2D image slice) in the sub-sarcolemmal region, whilst it was closer to 50% in the intermyofibrillar space. We finally demonstrate that our segmentations can be turned into 3D finite element meshes for cardiac cell computational physiology studies. We offer our large dataset and MATLAB implementation of the algorithm for research use at www.github.com/CellSMB/sbfsem-cardiac-cell-segmenter/. We anticipate that this timely tool will be of use to cardiac computational and experimental physiologists alike who study cardiac ultrastructure and its role in heart function.
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23
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Li YG, Dong ZF, Chen KK, He YP, Dai XY, Li S, Li JB, Zhu W, Wei M. Insulin upregulates GRIM-19 and protects cardiac mitochondrial morphology in type 1 diabetic rats partly through PI3K/AKT signaling pathway. Biochem Biophys Res Commun 2017; 493:611-617. [PMID: 28867181 DOI: 10.1016/j.bbrc.2017.08.144] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 08/24/2017] [Indexed: 12/29/2022]
Abstract
Insulin is involved in the development of diabetic heart disease and is important in the activities of mitochondrial complex I. However, the effect of insulin on cardiac mitochondrial nicotinamide adenine dinucleotide dehydrogenase (ubiquinone) 1 subunit of retinoic-interferon-induced mortality 19 (GRIM-19) has not been characterized. The aim of this study was to investigate the effect of insulin on the mitochondrial GRIM-19 in the hearts of rats with streptozotocin (STZ)-induced type 1 diabetes. Protein changes of GRIM-19 were evaluated by western blotting and reverse transcription-quantitative polymerase chain reaction. Furthermore, the effects of insulin on mitochondrial complex I were detected in HeLa cells and H9C2 cardiac myocytes. During the development of diabetic heart disease, the cardiac function did not change within the 8 weeks, but the mitochondrial morphology was altered. The hearts from the rats with STZ-induced diabetes exhibited reduced expression of GRIM-19. Prior to the overt cardiac dilatation, mitochondrial alterations were already present. Following subcutaneous insulin injection, it was demonstrated that GRIM-19 protein was altered, as well as the mitochondrial morphology. The phosphoinositide 3-kinase inhibitor LY294002 had an effect on insulin signaling in H9C2 cardiacmyocytes, and decreased the level of GRIM-19 by half compared with that in the insulin group. The results indicate that insulin is essential for the control of cardiac mitochondrial morphology and the GRIM-19 expression partly via PI3K/AKT signaling pathways.
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Affiliation(s)
- Yong-Guang Li
- Department of Cardiovascular Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, PR China.
| | - Zhi-Feng Dong
- Department of Cardiovascular Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, PR China
| | - Kan-Kai Chen
- Department of Cardiovascular Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, PR China
| | - Ya-Ping He
- Department of Cardiovascular Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, PR China
| | - Xiao-Yan Dai
- Department of Cardiovascular Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, PR China
| | - Shuai Li
- Department of Cardiovascular Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, PR China
| | - Jing-Bo Li
- Department of Cardiovascular Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, PR China
| | - Wei Zhu
- Department of Cardiovascular Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, PR China
| | - Meng Wei
- Department of Cardiovascular Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, PR China.
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24
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Ghosh S, Crampin EJ, Hanssen E, Rajagopal V. A computational study of the role of mitochondrial organization on cardiac bioenergetics. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2017:2696-2699. [PMID: 29060455 DOI: 10.1109/embc.2017.8037413] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
All cells in the body have a specific shape and internal organization which is specific to that cell's function. Heart cells are rod-shaped, and contain arrays of contractile protines (myofibrils) and mitochondria (organelles that produce energy) that are aligned along the length of the rod. This arrangement is presumed to allow the cell to generate maximal contractile force for each heartbeat and for energy metabolites to be readily available to generate this force. Heart disease phenotypes, such as diabetic cardiomyopathy and heart failure, exhibit altered organization of mitochondria. However, physiological and computational studies have predominantly investigated the effect of the biochemical changes that accompany the disease alone, such as reduced rates of ATP production by mitochondria. We present a modeling study that examines the effect of mitochondrial organization on energy metabolite distribution during the heartbeat. A 2D micrograph of the cell cross-section was selected from a 3D image stack of structural data of a cardiac cell. The image was used to generate a 2D finite element model, on which mitochondrial oxidative phosphorylation and energy metabolite diffusion was modelled. Results illustrate that mitochondrial density can induce heterogeneity in the distribution of metabolites across the cell area. We discuss the implications of these findings and avenues for future, more indepth studies.
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25
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Lu FM, Hilgemann DW. Na/K pump inactivation, subsarcolemmal Na measurements, and cytoplasmic ion turnover kinetics contradict restricted Na spaces in murine cardiac myocytes. J Gen Physiol 2017; 149:727-749. [PMID: 28606910 PMCID: PMC5496509 DOI: 10.1085/jgp.201711780] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/23/2017] [Indexed: 11/20/2022] Open
Abstract
The Na/K pump exports cytoplasmic Na ions while importing K ions, and its activity is thought to be affected by restricted intracellular Na diffusion in cardiac myocytes. Lu and Hilgemann find instead that the pump can enter an inactivated state and that inactivation can be relieved by cytoplasmic Na. Decades ago, it was proposed that Na transport in cardiac myocytes is modulated by large changes in cytoplasmic Na concentration within restricted subsarcolemmal spaces. Here, we probe this hypothesis for Na/K pumps by generating constitutive transsarcolemmal Na flux with the Na channel opener veratridine in whole-cell patch-clamp recordings. Using 25 mM Na in the patch pipette, pump currents decay strongly during continuous activation by extracellular K (τ, ∼2 s). In contradiction to depletion hypotheses, the decay becomes stronger when pump currents are decreased by hyperpolarization. Na channel currents are nearly unchanged by pump activity in these conditions, and conversely, continuous Na currents up to 0.5 nA in magnitude have negligible effects on pump currents. These outcomes are even more pronounced using 50 mM Li as a cytoplasmic Na congener. Thus, the Na/K pump current decay reflects mostly an inactivation mechanism that immobilizes Na/K pump charge movements, not cytoplasmic Na depletion. When channel currents are increased beyond 1 nA, models with unrestricted subsarcolemmal diffusion accurately predict current decay (τ ∼15 s) and reversal potential shifts observed for Na, Li, and K currents through Na channels opened by veratridine, as well as for Na, K, Cs, Li, and Cl currents recorded in nystatin-permeabilized myocytes. Ion concentrations in the pipette tip (i.e., access conductance) track without appreciable delay the current changes caused by sarcolemmal ion flux. Importantly, cytoplasmic mixing volumes, calculated from current decay kinetics, increase and decrease as expected with osmolarity changes (τ >30 s). Na/K pump current run-down over 20 min reflects a failure of pumps to recover from inactivation. Simulations reveal that pump inactivation coupled with Na-activated recovery enhances the rapidity and effectivity of Na homeostasis in cardiac myocytes. In conclusion, an autoregulatory mechanism enhances cardiac Na/K pump activity when cytoplasmic Na rises and suppresses pump activity when cytoplasmic Na declines.
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Affiliation(s)
- Fang-Min Lu
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX
| | - Donald W Hilgemann
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX
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26
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Gawthrop PJ. Bond Graph Modeling of Chemiosmotic Biomolecular Energy Transduction. IEEE Trans Nanobioscience 2017; 16:177-188. [PMID: 28252411 DOI: 10.1109/tnb.2017.2674683] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Engineering systems modeling and analysis based on the bond graph approach has been applied to biomolecular systems. In this context, the notion of a Faraday-equivalent chemical potential is introduced which allows chemical potential to be expressed in an analogous manner to electrical volts thus allowing engineering intuition to be applied to biomolecular systems. Redox reactions, and their representation by half-reactions, are key components of biological systems which involve both electrical and chemical domains. A bond graph interpretation of redox reactions is given which combines bond graphs with the Faraday-equivalent chemical potential. This approach is particularly relevant when the biomolecular system implements chemoelectrical transduction - for example chemiosmosis within the key metabolic pathway of mitochondria: oxidative phosphorylation. An alternative way of implementing computational modularity using bond graphs is introduced and used to give a physically based model of the mitochondrial electron transport chain To illustrate the overall approach, this model is analyzed using the Faraday-equivalent chemical potential approach and engineering intuition is used to guide affinity equalisation: a energy based analysis of the mitochondrial electron transport chain.
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