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Yang W, Lyu Y, Xiang R, Yang J. Long Noncoding RNAs in the Pathogenesis of Insulin Resistance. Int J Mol Sci 2022; 23:ijms232416054. [PMID: 36555704 PMCID: PMC9785789 DOI: 10.3390/ijms232416054] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/10/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Insulin resistance (IR), designated as the blunted response of insulin target tissues to physiological level of insulin, plays crucial roles in the development and progression of diabetes, nonalcoholic fatty liver disease (NAFLD) and other diseases. So far, the distinct mechanism(s) of IR still needs further exploration. Long non-coding RNA (lncRNA) is a class of non-protein coding RNA molecules with a length greater than 200 nucleotides. LncRNAs are widely involved in many biological processes including cell differentiation, proliferation, apoptosis and metabolism. More recently, there has been increasing evidence that lncRNAs participated in the pathogenesis of IR, and the dysregulated lncRNA profile played important roles in the pathogenesis of metabolic diseases including obesity, diabetes and NAFLD. For example, the lncRNAs MEG3, H19, MALAT1, GAS5, lncSHGL and several other lncRNAs have been shown to regulate insulin signaling and glucose/lipid metabolism in various tissues. In this review, we briefly introduced the general features of lncRNA and the methods for lncRNA research, and then summarized and discussed the recent advances on the roles and mechanisms of lncRNAs in IR, particularly focused on liver, skeletal muscle and adipose tissues.
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Affiliation(s)
- Weili Yang
- Beijing Key Laboratory of Diabetes Research and Care, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
| | - Yixiang Lyu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
- Key Laboratory of Cardiovascular Science of the Ministry of Education, Center for Non-Coding RNA Medicine, Beijing 100191, China
| | - Rui Xiang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
- Key Laboratory of Cardiovascular Science of the Ministry of Education, Center for Non-Coding RNA Medicine, Beijing 100191, China
| | - Jichun Yang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
- Key Laboratory of Cardiovascular Science of the Ministry of Education, Center for Non-Coding RNA Medicine, Beijing 100191, China
- Correspondence:
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2
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Krako Jakovljevic N, Pavlovic K, Zujovic T, Kravic-Stevovic T, Jotic A, Markovic I, Lalic NM. In vitro models of insulin resistance: Mitochondrial coupling is differently affected in liver and muscle cells. Mitochondrion 2021; 61:165-173. [PMID: 34634496 DOI: 10.1016/j.mito.2021.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 09/17/2021] [Accepted: 10/06/2021] [Indexed: 01/07/2023]
Abstract
Mitochondrial dysfunction in diabetes is a widely studied topic, but inconsistency in literature data suggests a need for valid and reproducible models that will help to clarify this interaction. We aimed to establish insulin resistance models using chronic high insulin treatment in two cell types: myocytes and hepatocytes, characterise them in terms of mitochondrial function and compare them to the widely used palmitate-induced model of insulin resistance. We found that insulin lowered phosphorylation of Akt while not affecting cell viability, ROS production, mitochondrial morphology or respiration, and caused decrease in mitochondrial coupling only in muscle but not in liver cells.
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Affiliation(s)
- Nina Krako Jakovljevic
- Clinic for Endocrinology, Diabetes and Metabolic Diseases, University Clinical Centre of Serbia, Faculty of Medicine, University of Belgrade, Dr Subotica 13, 11000 Belgrade, Serbia
| | - Kasja Pavlovic
- Clinic for Endocrinology, Diabetes and Metabolic Diseases, University Clinical Centre of Serbia, Faculty of Medicine, University of Belgrade, Dr Subotica 13, 11000 Belgrade, Serbia
| | - Tijana Zujovic
- Clinic for Endocrinology, Diabetes and Metabolic Diseases, University Clinical Centre of Serbia, Faculty of Medicine, University of Belgrade, Dr Subotica 13, 11000 Belgrade, Serbia
| | - Tamara Kravic-Stevovic
- Institute of Histology and Embryology, Faculty of Medicine, University of Belgrade, Visegradska 26, 11000 Belgrade, Serbia
| | - Aleksandra Jotic
- Clinic for Endocrinology, Diabetes and Metabolic Diseases, University Clinical Centre of Serbia, Faculty of Medicine, University of Belgrade, Dr Subotica 13, 11000 Belgrade, Serbia
| | - Ivanka Markovic
- Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, Pasterova 2, 11000 Belgrade, Serbia
| | - Nebojsa M Lalic
- Clinic for Endocrinology, Diabetes and Metabolic Diseases, University Clinical Centre of Serbia, Faculty of Medicine, University of Belgrade, Dr Subotica 13, 11000 Belgrade, Serbia.
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3
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Langlois A, Forterre A, Pinget M, Bouzakri K. Impact of moderate exercise on fatty acid oxidation in pancreatic β-cells and skeletal muscle. J Endocrinol Invest 2021; 44:1815-1825. [PMID: 33844166 PMCID: PMC8357749 DOI: 10.1007/s40618-021-01551-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/03/2021] [Indexed: 12/13/2022]
Abstract
Fatty acids (FA) play a crucial role in glycaemia regulation in healthy and metabolic disorders conditions through various mechanisms. FA oxidation is one of the processes involved in lipid metabolism and can be modulated by exercise. Nowadays, physical activity is known to be an effective strategy for the prevention and treatment of Type 2 Diabetes. Moreover, its intensity, its duration, the sex-gender, the prandial state, exerkines… are as many parameters that can influence glycaemic control. However, the widely debated question is to determine the best type of exercise for patients with metabolic disorders. In this review, we will discuss the impact of exercise intensity, especially moderate activity, on glycaemic control by focussing on FA oxidation in pancreatic β-cells and skeletal muscle. Finally, thanks to all the recent data, we will determine whether moderate physical activity is a good therapeutic strategy and if FA oxidation represents a target of interest to treat diabetic, obese and insulin-resistant patients.
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Affiliation(s)
- A Langlois
- Centre Européen D'étude du Diabète, Unité Mixte de Recherche de L'Université de Strasbourg « Diabète et Thérapeutique », Strasbourg, France
| | - A Forterre
- Centre Européen D'étude du Diabète, Unité Mixte de Recherche de L'Université de Strasbourg « Diabète et Thérapeutique », Strasbourg, France
| | - M Pinget
- Centre Européen D'étude du Diabète, Unité Mixte de Recherche de L'Université de Strasbourg « Diabète et Thérapeutique », Strasbourg, France
| | - K Bouzakri
- Centre Européen D'étude du Diabète, Unité Mixte de Recherche de L'Université de Strasbourg « Diabète et Thérapeutique », Strasbourg, France.
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4
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Axelrod CL, Fealy CE, Erickson ML, Davuluri G, Fujioka H, Dantas WS, Huang E, Pergola K, Mey JT, King WT, Mulya A, Hsia D, Burguera B, Tandler B, Hoppel CL, Kirwan JP. Lipids activate skeletal muscle mitochondrial fission and quality control networks to induce insulin resistance in humans. Metabolism 2021; 121:154803. [PMID: 34090870 PMCID: PMC8277749 DOI: 10.1016/j.metabol.2021.154803] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/10/2021] [Accepted: 05/31/2021] [Indexed: 12/27/2022]
Abstract
BACKGROUND AND AIMS A diminution in skeletal muscle mitochondrial function due to ectopic lipid accumulation and excess nutrient intake is thought to contribute to insulin resistance and the development of type 2 diabetes. However, the functional integrity of mitochondria in insulin-resistant skeletal muscle remains highly controversial. METHODS 19 healthy adults (age:28.4 ± 1.7 years; BMI:22.7 ± 0.3 kg/m2) received an overnight intravenous infusion of lipid (20% Intralipid) or saline followed by a hyperinsulinemic-euglycemic clamp to assess insulin sensitivity using a randomized crossover design. Skeletal muscle biopsies were obtained after the overnight lipid infusion to evaluate activation of mitochondrial dynamics proteins, ex-vivo mitochondrial membrane potential, ex-vivo oxidative phosphorylation and electron transfer capacity, and mitochondrial ultrastructure. RESULTS Overnight lipid infusion increased dynamin related protein 1 (DRP1) phosphorylation at serine 616 and PTEN-induced kinase 1 (PINK1) expression (P = 0.003 and P = 0.008, respectively) in skeletal muscle while reducing mitochondrial membrane potential (P = 0.042). The lipid infusion also increased mitochondrial-associated lipid droplet formation (P = 0.011), the number of dilated cristae, and the presence of autophagic vesicles without altering mitochondrial number or respiratory capacity. Additionally, lipid infusion suppressed peripheral glucose disposal (P = 0.004) and hepatic insulin sensitivity (P = 0.014). CONCLUSIONS These findings indicate that activation of mitochondrial fission and quality control occur early in the onset of insulin resistance in human skeletal muscle. Targeting mitochondrial dynamics and quality control represents a promising new pharmacological approach for treating insulin resistance and type 2 diabetes. CLINICAL TRIAL REGISTRATION NCT02697201, ClinicalTrials.gov.
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Affiliation(s)
- Christopher L Axelrod
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA; Department of Translational Services, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA; Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Ciaran E Fealy
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Melissa L Erickson
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA; Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Gangarao Davuluri
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA; Sarcopenia and Malnutrition Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Hisashi Fujioka
- Cryo-Electron Microscopy Core, Case Western Reserve University, Cleveland, OH 44109, USA; Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Wagner S Dantas
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Emily Huang
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Kathryn Pergola
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA; Department of Translational Services, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Jacob T Mey
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA; Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - William T King
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA; Department of Translational Services, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Anny Mulya
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Daniel Hsia
- Clinical Trials Unit, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Bartolome Burguera
- Endocrinology and Metabolism Institute, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Bernard Tandler
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Department of Biological Sciences, Case Western Reserve University School of Dental Medicine, Cleveland, OH 44106, USA
| | - Charles L Hoppel
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA; Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44109, USA
| | - John P Kirwan
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA; Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
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5
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Truong NTT, Lydic TA, Bazil JN, Suryadevara A, Olson LK. Regulation of lipid metabolism in pancreatic beta cells by interferon gamma: A link to anti-viral function. Cytokine 2020; 133:155147. [PMID: 32492632 DOI: 10.1016/j.cyto.2020.155147] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 05/01/2020] [Accepted: 05/25/2020] [Indexed: 12/22/2022]
Abstract
Interferons (IFN) have been shown to alter lipid metabolism in immune and some non-hematopoietic cells and this affects host cell response to pathogens. In type 1 diabetes, IFNγ acts as a proinflammatory cytokine that, along with other cytokines, is released during pancreatic beta cell autoinflammation and contributes to immune response and beta cell dysfunction. The hypothesis tested herein is that IFN modifies beta cell lipid metabolism and this is associated with enhanced anti-viral response and beta cell stress. Treatment of INS-1 cells with IFNγ for 6 to 24 h led to a dynamic change in TAG and lipid droplet (LD) levels, with a decrease at 6 h and an increase at 24 h. The later accumulation of TAG was associated with increased de novo lipogenesis (DNL), and impaired mitochondrial fatty acid oxidation (FAO). Gene expression results suggested that IFNγ regulates lipolytic, lipogenic, LD and FAO genes in a temporal manner. The changes in lipid gene expression are dependent on the classical Janus kinase (JAK) pathway. Pretreatment with IFNγ robustly enhanced anti-viral gene expression induced by the viral mimetic polyinosinic: polycytidylic acid (PIC), and this potentiating effect of IFNγ was markedly attenuated by inhibitors of DNL. The IFNγ-induced accumulation of lipid, however, was insufficient to cause endoplasmic reticulum (ER) stress. These studies demonstrated a non-canonical effect of IFNγ in regulation of pancreatic beta cell lipid metabolism that is intimately linked with host cell defense and might alter cellular function early in the progression to type 1 diabetes.
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Affiliation(s)
- Nguyen T T Truong
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Todd A Lydic
- Department of Physiology, Michigan State University, East Lansing, MI, United States; Mass Spectrometry Core (MMD-CMSC), Michigan State University, East Lansing, MI, United States
| | - Jason N Bazil
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Abhijeet Suryadevara
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - L Karl Olson
- Department of Physiology, Michigan State University, East Lansing, MI, United States.
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Brunetta HS, de Paula GC, de Oliveira J, Martins EL, Dos Santos GJ, Galina A, Rafacho A, de Bem AF, Nunes EA. Decrement in resting and insulin-stimulated soleus muscle mitochondrial respiration is an early event in diet-induced obesity in mice. Exp Physiol 2019; 104:306-321. [PMID: 30578638 DOI: 10.1113/ep087317] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 12/19/2018] [Indexed: 01/08/2023]
Abstract
NEW FINDINGS What is the central question of this study? What are the temporal responses of mitochondrial respiration and mitochondrial responsivity to insulin in soleus muscle fibres from mice during the development of obesity and insulin resistance? What is the main finding and its importance? Short- and long-term feeding with a high-fat diet markedly reduced soleus mitochondrial respiration and mitochondrial responsivity to insulin before any change in glycogen synthesis. Muscle glycogen synthesis and whole-body insulin resistance were present after 14 and 28 days, respectively. Our findings highlight the plasticity of mitochondria during the development of obesity and insulin resistance. ABSTRACT Recently, significant attention has been given to the role of muscle mitochondrial function in the development of insulin resistance associated with obesity. Our aim was to investigate temporal alterations in mitochondrial respiration, H2 O2 emission and mitochondrial responsivity to insulin in permeabilized skeletal muscle fibres during the development of obesity in mice. Male Swiss mice (5-6 weeks old) were fed with a high-fat diet (60% calories from fat) or standard diet for 7, 14 or 28 days to induce obesity and insulin resistance. Diet-induced obese (DIO) mice presented with reduced glucose tolerance and hyperinsulinaemia after 7 days of high-fat diet. After 14 days, the expected increase in muscle glycogen content after systemic injection of glucose and insulin was not observed in DIO mice. At 28 days, blood glucose decay after insulin injection was significantly impaired. Complex I (pyruvate + malate) and II (succinate)-linked respiration and oxidative phosphorylation (ADP) were decreased after 7 days of high-fat diet and remained low in DIO mice after 14 and 28 days of treatment. Moreover, mitochondria from DIO mice were incapable of increasing respiratory coupling and ADP responsivity after insulin stimulation in all observed periods. Markers of mitochondrial content were reduced only after 28 days of treatment. The mitochondrial H2 O2 emission profile varied during the time course of DIO, with a reduction of H2 O2 emission in the early stages of DIO and an increased emission after 28 days of treatment. Our data demonstrate that DIO promotes transitory alterations in mitochondrial physiology during the early and late stages of insulin resistance related to obesity.
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Affiliation(s)
- Henver Simionato Brunetta
- Multicenter Graduate Program in Physiological Sciences, Federal University of Santa Catarina, Florianopólis, Santa Catrina, Brazil
| | - Gabriela Cristina de Paula
- Graduate Program in Biochemistry, Federal University of Santa Catarina, Florianopólis, Santa Catrina, Brazil
| | - Jade de Oliveira
- Graduate Program in Health Sciences, University of Extremo Sul Catarinense, Criciúma, Santa Catarina, Brazil
| | - Eduarda Lopes Martins
- Graduate Program in Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gustavo Jorge Dos Santos
- Multicenter Graduate Program in Physiological Sciences, Federal University of Santa Catarina, Florianopólis, Santa Catrina, Brazil
| | - Antonio Galina
- Graduate Program in Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alex Rafacho
- Multicenter Graduate Program in Physiological Sciences, Federal University of Santa Catarina, Florianopólis, Santa Catrina, Brazil
| | - Andreza Fabro de Bem
- Graduate Program in Biochemistry, Federal University of Santa Catarina, Florianopólis, Santa Catrina, Brazil.,Department of Physiological Sciences, Institute of Biological Sciences, University of Brasília, Brasília, Distrito Federal, Brazil
| | - Everson Araújo Nunes
- Multicenter Graduate Program in Physiological Sciences, Federal University of Santa Catarina, Florianopólis, Santa Catrina, Brazil
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Gancheva S, Jelenik T, Álvarez-Hernández E, Roden M. Interorgan Metabolic Crosstalk in Human Insulin Resistance. Physiol Rev 2018; 98:1371-1415. [PMID: 29767564 DOI: 10.1152/physrev.00015.2017] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Excessive energy intake and reduced energy expenditure drive the development of insulin resistance and metabolic diseases such as obesity and type 2 diabetes mellitus. Metabolic signals derived from dietary intake or secreted from adipose tissue, gut, and liver contribute to energy homeostasis. Recent metabolomic studies identified novel metabolites and enlarged our knowledge on classic metabolites. This review summarizes the evidence of their roles as mediators of interorgan crosstalk and regulators of insulin sensitivity and energy metabolism. Circulating lipids such as free fatty acids, acetate, and palmitoleate from adipose tissue and short-chain fatty acids from the gut effectively act on liver and skeletal muscle. Intracellular lipids such as diacylglycerols and sphingolipids can serve as lipotoxins by directly inhibiting insulin action in muscle and liver. In contrast, fatty acid esters of hydroxy fatty acids have been recently shown to exert a series of beneficial effects. Also, ketoacids are gaining interest as potent modulators of insulin action and mitochondrial function. Finally, branched-chain amino acids not only predict metabolic diseases, but also inhibit insulin signaling. Here, we focus on the metabolic crosstalk in humans, which regulates insulin sensitivity and energy homeostasis in the main insulin-sensitive tissues, skeletal muscle, liver, and adipose tissue.
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Affiliation(s)
- Sofiya Gancheva
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University , Düsseldorf , Germany ; Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University , Düsseldorf , Germany ; and German Center of Diabetes Research (DZD e.V.), Munich- Neuherberg , Germany
| | - Tomas Jelenik
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University , Düsseldorf , Germany ; Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University , Düsseldorf , Germany ; and German Center of Diabetes Research (DZD e.V.), Munich- Neuherberg , Germany
| | - Elisa Álvarez-Hernández
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University , Düsseldorf , Germany ; Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University , Düsseldorf , Germany ; and German Center of Diabetes Research (DZD e.V.), Munich- Neuherberg , Germany
| | - Michael Roden
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University , Düsseldorf , Germany ; Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University , Düsseldorf , Germany ; and German Center of Diabetes Research (DZD e.V.), Munich- Neuherberg , Germany
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8
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Fealy CE, Mulya A, Axelrod CL, Kirwan JP. Mitochondrial dynamics in skeletal muscle insulin resistance and type 2 diabetes. Transl Res 2018; 202:69-82. [PMID: 30153426 DOI: 10.1016/j.trsl.2018.07.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 07/08/2018] [Accepted: 07/23/2018] [Indexed: 01/09/2023]
Abstract
The traditional view of mitochondria as isolated, spherical, energy producing organelles, is undergoing a revolutionary change. Emerging data show that mitochondria form a dynamic reticulum that is regulated by cycles of fission and fusion. The discovery of proteins that modulate these activities has led to important advances in understanding human disease. Here, we review the latest evidence that connects the emerging field of mitochondrial dynamics to skeletal muscle insulin resistance and propose some potential mechanisms that may explain the long debated link between mitochondria and the development of type 2 diabetes.
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Affiliation(s)
- CiarÁn E Fealy
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Anny Mulya
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Christopher L Axelrod
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; Integrated Physiology and Molecular Metabolism Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana
| | - John P Kirwan
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; Integrated Physiology and Molecular Metabolism Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana.
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9
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Corbin KD, Driscoll KA, Pratley RE, Smith SR, Maahs DM, Mayer-Davis EJ. Obesity in Type 1 Diabetes: Pathophysiology, Clinical Impact, and Mechanisms. Endocr Rev 2018; 39:629-663. [PMID: 30060120 DOI: 10.1210/er.2017-00191] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 06/21/2018] [Indexed: 02/07/2023]
Abstract
There has been an alarming increase in the prevalence of obesity in people with type 1 diabetes in recent years. Although obesity has long been recognized as a major risk factor for the development of type 2 diabetes and a catalyst for complications, much less is known about the role of obesity in the initiation and pathogenesis of type 1 diabetes. Emerging evidence suggests that obesity contributes to insulin resistance, dyslipidemia, and cardiometabolic complications in type 1 diabetes. Unique therapeutic strategies may be required to address these comorbidities within the context of intensive insulin therapy, which promotes weight gain. There is an urgent need for clinical guidelines for the prevention and management of obesity in type 1 diabetes. The development of these recommendations will require a transdisciplinary research strategy addressing metabolism, molecular mechanisms, lifestyle, neuropsychology, and novel therapeutics. In this review, the prevalence, clinical impact, energy balance physiology, and potential mechanisms of obesity in type 1 diabetes are described, with a special focus on the substantial gaps in knowledge in this field. Our goal is to provide a framework for the evidence base needed to develop type 1 diabetes-specific weight management recommendations that account for the competing outcomes of glycemic control and weight management.
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Affiliation(s)
- Karen D Corbin
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida
| | - Kimberly A Driscoll
- Department of Pediatrics, School of Medicine, University of Colorado Denver, Aurora, Colorado.,Barbara Davis Center for Diabetes, Aurora, Colorado
| | - Richard E Pratley
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida
| | - Steven R Smith
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida
| | - David M Maahs
- Division of Pediatric Endocrinology, Department of Pediatrics, Stanford University, Stanford, California
| | - Elizabeth J Mayer-Davis
- Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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10
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Mey JT, Haus JM. Dicarbonyl Stress and Glyoxalase-1 in Skeletal Muscle: Implications for Insulin Resistance and Type 2 Diabetes. Front Cardiovasc Med 2018; 5:117. [PMID: 30250846 PMCID: PMC6139330 DOI: 10.3389/fcvm.2018.00117] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 08/09/2018] [Indexed: 01/01/2023] Open
Abstract
Glyoxalase-1 (GLO1) is a ubiquitously expressed cytosolic protein which plays a role in the natural maintenance of cellular health and is abundantly expressed in human skeletal muscle. A consequence of reduced GLO1 protein expression is cellular dicarbonyl stress, which is elevated in obesity, insulin resistance and type 2 diabetes (T2DM). Both in vitro and pre-clinical models suggest dicarbonyl stress per se induces insulin resistance and is prevented by GLO1 overexpression, implicating a potential role for GLO1 therapy in insulin resistance and type 2 diabetes (T2DM). Recent work has identified the therapeutic potential of novel natural agents as a GLO1 inducer, which resulted in improved whole-body metabolism in obese adults. Given skeletal muscle is a major contributor to whole-body glucose, lipid, and protein metabolism, such GLO1 inducers may act, in part, through mechanisms in skeletal muscle. Currently, investigations examining the specificity of dicarbonyl stress and GLO1 biology in human skeletal muscle are lacking. Recent work from our lab indicates that dysregulation of GLO1 in skeletal muscle may underlie human insulin resistance and that exercise training may impart therapeutic benefits. This minireview will summarize the existing human literature examining skeletal muscle GLO1 and highlight the emerging therapeutic concepts for GLO1 gain-of-function in conditions such as insulin resistance and cardiometabolic disease.
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Affiliation(s)
- Jacob T Mey
- Department of Pathobiology, Cleveland Clinic, Cleveland, OH, United States
| | - Jacob M Haus
- School of Kinesiology, University of Michigan, Ann Arbor, MI, United States
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11
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Botteri G, Salvadó L, Gumà A, Lee Hamilton D, Meakin PJ, Montagut G, Ashford MLJ, Ceperuelo-Mallafré V, Fernández-Veledo S, Vendrell J, Calderón-Dominguez M, Serra D, Herrero L, Pizarro J, Barroso E, Palomer X, Vázquez-Carrera M. The BACE1 product sAPPβ induces ER stress and inflammation and impairs insulin signaling. Metabolism 2018. [PMID: 29526536 DOI: 10.1016/j.metabol.2018.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE β-secretase/β-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) is a key enzyme involved in Alzheimer's disease that has recently been implicated in insulin-independent glucose uptake in myotubes. However, it is presently unknown whether BACE1 and the product of its activity, soluble APPβ (sAPPβ), contribute to lipid-induced inflammation and insulin resistance in skeletal muscle cells. MATERIALS/METHODS Studies were conducted in mouse C2C12 myotubes, skeletal muscle from Bace1-/-mice and mice treated with sAPPβ and adipose tissue and plasma from obese and type 2 diabetic patients. RESULTS We show that BACE1 inhibition or knockdown attenuates palmitate-induced endoplasmic reticulum (ER) stress, inflammation, and insulin resistance and prevents the reduction in Peroxisome Proliferator-Activated Receptor γ Co-activator 1α (PGC-1α) and fatty acid oxidation caused by palmitate in myotubes. The effects of palmitate on ER stress, inflammation, insulin resistance, PGC-1α down-regulation, and fatty acid oxidation were mimicked by soluble APPβ in vitro. BACE1 expression was increased in subcutaneous adipose tissue of obese and type 2 diabetic patients and this was accompanied by a decrease in PGC-1α mRNA levels and by an increase in sAPPβ plasma levels of obese type 2 diabetic patients compared to obese non-diabetic subjects. Acute sAPPβ administration to mice reduced PGC-1α levels and increased inflammation in skeletal muscle and decreased insulin sensitivity. CONCLUSIONS Collectively, these findings indicate that the BACE1 product sAPPβ is a key determinant in ER stress, inflammation and insulin resistance in skeletal muscle and gluconeogenesis in liver.
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Affiliation(s)
- Gaia Botteri
- Pharmacology Unit, Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Spain; Institut de Biomedicina de la Universitat de Barcelona (IBUB), Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain; Institut de Recerca Sant Joan de Déu (IR-SJD), Esplugues de Llobregat, Barcelona, Spain
| | - Laia Salvadó
- Pharmacology Unit, Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Spain; Institut de Biomedicina de la Universitat de Barcelona (IBUB), Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain; Institut de Recerca Sant Joan de Déu (IR-SJD), Esplugues de Llobregat, Barcelona, Spain
| | - Anna Gumà
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain; Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - D Lee Hamilton
- Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital & Medical School, University of Dundee, Dundee, UK
| | - Paul J Meakin
- Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital & Medical School, University of Dundee, Dundee, UK
| | - Gemma Montagut
- Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital & Medical School, University of Dundee, Dundee, UK
| | - Michael L J Ashford
- Division of Molecular and Clinical Medicine, School of Medicine, Ninewells Hospital & Medical School, University of Dundee, Dundee, UK
| | - Victoria Ceperuelo-Mallafré
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain; Hospital Universitari de Tarragona Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Tarragona, Spain
| | - Sonia Fernández-Veledo
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain; Hospital Universitari de Tarragona Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Tarragona, Spain
| | - Joan Vendrell
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain; Hospital Universitari de Tarragona Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Tarragona, Spain
| | - María Calderón-Dominguez
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Spain; Department of Biochemistry and Physiology, Faculty of Pharmacy and Food Sciences, University of Barcelona, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Barcelona, Spain
| | - Dolors Serra
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Spain; Department of Biochemistry and Physiology, Faculty of Pharmacy and Food Sciences, University of Barcelona, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Barcelona, Spain
| | - Laura Herrero
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Spain; Department of Biochemistry and Physiology, Faculty of Pharmacy and Food Sciences, University of Barcelona, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Barcelona, Spain
| | - Javier Pizarro
- Pharmacology Unit, Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Spain; Institut de Biomedicina de la Universitat de Barcelona (IBUB), Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain; Institut de Recerca Sant Joan de Déu (IR-SJD), Esplugues de Llobregat, Barcelona, Spain
| | - Emma Barroso
- Pharmacology Unit, Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Spain; Institut de Biomedicina de la Universitat de Barcelona (IBUB), Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain; Institut de Recerca Sant Joan de Déu (IR-SJD), Esplugues de Llobregat, Barcelona, Spain
| | - Xavier Palomer
- Pharmacology Unit, Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Spain; Institut de Biomedicina de la Universitat de Barcelona (IBUB), Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain; Institut de Recerca Sant Joan de Déu (IR-SJD), Esplugues de Llobregat, Barcelona, Spain
| | - Manuel Vázquez-Carrera
- Pharmacology Unit, Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, Spain; Institut de Biomedicina de la Universitat de Barcelona (IBUB), Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain; Institut de Recerca Sant Joan de Déu (IR-SJD), Esplugues de Llobregat, Barcelona, Spain.
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12
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Insulin resistance in obesity: an overview of fundamental alterations. Eat Weight Disord 2018; 23:149-157. [PMID: 29397563 DOI: 10.1007/s40519-018-0481-6] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 01/12/2018] [Indexed: 12/14/2022] Open
Abstract
Obesity is a major health risk factor, and obesity-induced morbidity and complications account for huge costs for affected individuals, families, healthcare systems, and society at large. In particular, obesity is strongly associated with the development of insulin resistance, which in turn plays a key role in the pathogenesis of obesity-associated cardiometabolic complications, including metabolic syndrome components, type 2 diabetes, and cardiovascular diseases. Insulin sensitive tissues, including adipose tissue, skeletal muscle, and liver, are profoundly affected by obesity both at biomolecular and functional levels. Altered adipose organ function may play a fundamental pathogenetic role once fat accumulation has ensued. Modulation of insulin sensitivity appears to be, at least in part, related to changes in redox balance and oxidative stress as well as inflammation, with a relevant underlying role for mitochondrial dysfunction that may exacerbate these alterations. Nutrients and substrates as well as systems involved in host-nutrient interactions, including gut microbiota, have been also identified as modulators of metabolic pathways controlling insulin action. This review aims at providing an overview of these concepts and their potential inter-relationships in the development of insulin resistance, with particular regard to changes in adipose organ and skeletal muscle.
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Kahl S, Nowotny B, Strassburger K, Bierwagen A, Klüppelholz B, Hoffmann B, Giani G, Nowotny PJ, Wallscheid F, Hatziagelaki E, Pacini G, Hwang JH, Roden M. Amino Acid and Fatty Acid Levels Affect Hepatic Phosphorus Metabolite Content in Metabolically Healthy Humans. J Clin Endocrinol Metab 2018; 103:460-468. [PMID: 29140513 DOI: 10.1210/jc.2017-01773] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/08/2017] [Indexed: 02/13/2023]
Abstract
OBJECTIVE Hepatic energy metabolism negatively relates to insulin resistance and liver fat content in patients with type 2 diabetes, but its role in metabolically healthy humans is unclear. We hypothesized that intrahepatocellular γ-adenosine triphosphate (γATP) and inorganic phosphate (Pi) concentrations exhibit similar associations with insulin sensitivity in nondiabetic, nonobese volunteers. DESIGN A total of 76 participants underwent a four-point sampling, 75-g oral glucose tolerance test (OGTT), as well as in vivo31P/1H magnetic resonance spectroscopy. In 62 of them, targeted plasma metabolomic profiling was performed. Pearson correlation analyses were performed for the dependent variables γATP and Pi. RESULTS Adjusted for age, sex, and body mass index (BMI), hepatic γATP and Pi related to 2-hour OGTT glucose (r = 0.25 and r = 0.27, both P < 0.05), and Pi further associated with nonesterified fatty acids (NEFAs; r = 0.28, P < 0.05). However, neither γATP nor Pi correlated with several measures of insulin sensitivity. Hepatic γATP correlated with circulating leucine (r = 0.42, P < 0.001) and Pi with C16:1 fatty acids palmitoleic acid and C16:1w5 (r = 0.28 and 0.30, respectively, P < 0.01), as well as with δ-9-desaturase index (r = 0.33, P < 0.05). Only the association of γATP with leucine remained important after correction for multiple testing. Leucine and palmitoleic acid, together with age, sex, and BMI, accounted for 26% and for 15% of the variabilities in γATP and Pi, respectively. CONCLUSIONS Specific circulating amino acids and NEFAs, but not measures of insulin sensitivity, partly affect hepatic phosphorus metabolites, suggesting mutual interaction between hepatic energy metabolism and circulating metabolites in nondiabetic humans.
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Affiliation(s)
- Sabine Kahl
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine University, Düsseldorf, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
| | - Bettina Nowotny
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine University, Düsseldorf, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
| | - Klaus Strassburger
- German Center for Diabetes Research, München-Neuherberg, Germany
- Institute for Biometrics and Epidemiology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany
| | - Alessandra Bierwagen
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine University, Düsseldorf, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
| | - Birgit Klüppelholz
- German Center for Diabetes Research, München-Neuherberg, Germany
- Institute for Biometrics and Epidemiology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany
| | - Barbara Hoffmann
- Institute for Occupational, Social and Environmental Medicine, Medical Faculty, Düsseldorf, Germany
| | - Guido Giani
- German Center for Diabetes Research, München-Neuherberg, Germany
- Institute for Biometrics and Epidemiology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany
| | - Peter J Nowotny
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine University, Düsseldorf, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
| | - Franziska Wallscheid
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine University, Düsseldorf, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
| | - Erifili Hatziagelaki
- 2nd Department of Internal Medicine, Research Institute and Diabetes Center, Athens University, "Attikon" University General Hospital, Athens, Greece
| | - Giovanni Pacini
- Metabolic Unit, Institute of Neuroscience, Consiglio Nazionale delle Ricerche, Padova, Italy
| | - Jong-Hee Hwang
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine University, Düsseldorf, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
| | - Michael Roden
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine University, Düsseldorf, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
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Eldor R, Norton L, Fourcaudot M, Galindo C, DeFronzo RA, Abdul-Ghani M. Increased lipid availability for three days reduces whole body glucose uptake, impairs muscle mitochondrial function and initiates opposing effects on PGC-1α promoter methylation in healthy subjects. PLoS One 2017; 12:e0188208. [PMID: 29261667 PMCID: PMC5737973 DOI: 10.1371/journal.pone.0188208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/02/2017] [Indexed: 11/19/2022] Open
Abstract
Aims FFA and FFA metabolites cause insulin resistance and impair beta cell function. The goal of our research was to examine whether elevation of plasma FFA impairs mitochondrial function and alters PGC-1α promoter methylation. Methods In this uncontrolled, change from baseline study design, insulin sensitivity and glucose-stimulated insulin secretion were measured in 9 normal glucose tolerant subjects before and after 3 day lipid infusion to elevate plasma FFA concentration. Vastus lateralis muscle biopsies were obtained and mitochondrial function, PGC-1α expression, and PGC-1α promoter methylation were quantitated. Results Increased plasma FFA (440±93 μmol/Lto 997±242 μM, p<0.001) decreased insulin-stimulated total glucose disposal (TGD) by 25% (p = 0.008), impaired suppression of endogenous glucose production (p = 0.01), and reduced mitochondrial ATP synthesis with complex 1 (34%, p<0.05) and complex 2 (30%, p<0.05) substrates. Lipid infusion had no effect on muscle PGC-1α RNA expression, total methylation or non-CpG methylation, but methylation of the alternative PGC-1α promoter decreased (1.30±0.30 to 0.84±0.15% methylated residues/patient•strand, p = 0.055). Within PGC-1α promoter there was demethylation of CpT residues (0.72±0.16 vs. 0.28±0.10 methylated residues/patient•strand) (p = 0.002), which was inversely correlated with PGC-1α mRNA expression (r = -0.94, p<0.0001) and ATP synthesis with complex 1 (r = -0.80, p<0.01) and complex 2 (r = -0.69, p<0.05) substrates. Lipid infusion increased DNMT-3B (methyltransferase associated with PGC-1α promoter non-CpG methylation) mRNA expression (0.87 ± 0.09 to 1.62 ± 0.22 arbitrary units, p = 0.005), which correlated inversely with CpT demethylation (r = 0.67, p<0.05). Conclusion/Interpretation Physiologic plasma FFA elevation in NGT individuals has opposing effects on PGC-1α non-CpG residue methylation (CpT demethylation and increased DNMT-3B expression), which is correlated with changes in PGC-1α expression and skeletal muscle mitochondrial function.
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Affiliation(s)
- Roy Eldor
- Diabetes Unit, Institute for Metabolism, Endocrinology and Hypertension, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
- * E-mail:
| | - Luke Norton
- Division of Diabetes, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Marcel Fourcaudot
- Division of Diabetes, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Cynthia Galindo
- Division of Diabetes, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Ralph A. DeFronzo
- Division of Diabetes, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Muhammad Abdul-Ghani
- Division of Diabetes, University of Texas Health Science Center, San Antonio, Texas, United States of America
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Gonzalez-Franquesa A, Patti ME. Insulin Resistance and Mitochondrial Dysfunction. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:465-520. [DOI: 10.1007/978-3-319-55330-6_25] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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16
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Jenkinson CP, Göring HH, Arya R, Blangero J, Duggirala R, DeFronzo RA. Transcriptomics in type 2 diabetes: Bridging the gap between genotype and phenotype. GENOMICS DATA 2016; 8:25-36. [PMID: 27114903 PMCID: PMC4832048 DOI: 10.1016/j.gdata.2015.12.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 11/19/2015] [Accepted: 12/14/2015] [Indexed: 02/06/2023]
Abstract
Type 2 diabetes (T2D) is a common, multifactorial disease that is influenced by genetic and environmental factors and their interactions. However, common variants identified by genome wide association studies (GWAS) explain only about 10% of the total trait variance for T2D and less than 5% of the variance for obesity, indicating that a large proportion of heritability is still unexplained. The transcriptomic approach described here uses quantitative gene expression and disease-related physiological data (deep phenotyping) to measure the direct correlation between the expression of specific genes and physiological traits. Transcriptomic analysis bridges the gulf between GWAS and physiological studies. Recent GWAS studies have utilized very large population samples, numbering in the tens of thousands (or even hundreds of thousands) of individuals, yet establishing causal functional relationships between strongly associated genetic variants and disease remains elusive. In light of the findings described below, it is appropriate to consider how and why transcriptomic approaches in small samples might be capable of identifying complex disease-related genes which are not apparent using GWAS in large samples.
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Affiliation(s)
- Christopher P. Jenkinson
- South Texas Diabetes and Obesity Institute (STDOI), University of Texas Rio Grande Valley (UTRGV), TX, USA
| | - Harald H.H. Göring
- South Texas Diabetes and Obesity Institute (STDOI), University of Texas Rio Grande Valley (UTRGV), TX, USA
| | - Rector Arya
- South Texas Diabetes and Obesity Institute (STDOI), University of Texas Rio Grande Valley (UTRGV), TX, USA
| | - John Blangero
- South Texas Diabetes and Obesity Institute (STDOI), University of Texas Rio Grande Valley (UTRGV), TX, USA
| | - Ravindranath Duggirala
- South Texas Diabetes and Obesity Institute (STDOI), University of Texas Rio Grande Valley (UTRGV), TX, USA
| | - Ralph A. DeFronzo
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, TX, USA
- South Texas Veterans Health Care System, San Antonio, TX, USA
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Sparks LM, Gemmink A, Phielix E, Bosma M, Schaart G, Moonen-Kornips E, Jörgensen JA, Nascimento EBM, Hesselink MKC, Schrauwen P, Hoeks J. ANT1-mediated fatty acid-induced uncoupling as a target for improving myocellular insulin sensitivity. Diabetologia 2016; 59:1030-9. [PMID: 26886198 PMCID: PMC4826430 DOI: 10.1007/s00125-016-3885-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/15/2016] [Indexed: 12/29/2022]
Abstract
AIMS/HYPOTHESIS Dissipating energy via mitochondrial uncoupling has been suggested to contribute to enhanced insulin sensitivity. We hypothesised that skeletal muscle mitochondria of endurance-trained athletes have increased sensitivity for fatty acid (FA)-induced uncoupling, which is driven by the mitochondrial protein adenine nucleotide translocase 1 (ANT1). METHODS Capacity for FA-induced uncoupling was measured in endurance-trained male athletes (T) and sedentary young men (UT) in an observational study and also in isolated skeletal muscle mitochondria from Zucker diabetic fatty (ZDF) rats and C2C12 myotubes following small interfering RNA (siRNA)-mediated gene silencing of ANT1. Thus, fuelled by glutamate/succinate (fibres) or pyruvate (mitochondria and myotubes) and in the presence of oligomycin to block ATP synthesis, increasing levels of oleate (fibres) or palmitate (mitochondria and myotubes) were automatically titrated while respiration was monitored. Insulin sensitivity was measured by hyperinsulinaemic-euglycaemic clamp in humans and via insulin-stimulated glucose uptake in myotubes. RESULTS Skeletal muscle from the T group displayed increased sensitivity to FA-induced uncoupling (p = 0.011) compared with muscle from the UT group, and this was associated with elevated insulin sensitivity (p = 0.034). ANT1 expression was increased in T (p = 0.013). Mitochondria from ZDF rats displayed decreased sensitivity for FA-induced uncoupling (p = 0.008). This difference disappeared in the presence of the adenine nucleotide translocator inhibitor carboxyatractyloside. Partial knockdown of ANT1 in C2C12 myotubes decreased sensitivity to the FA-induced uncoupling (p = 0.008) and insulin-stimulated glucose uptake (p = 0.025) compared with controls. CONCLUSIONS/INTERPRETATION Increased sensitivity to FA-induced uncoupling is associated with enhanced insulin sensitivity and is affected by ANT1 activity in skeletal muscle. FA-induced mitochondrial uncoupling may help to preserve insulin sensitivity in the face of a high supply of FAs. TRIAL REGISTRATION www.trialregister.nl NTR2002.
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Affiliation(s)
- Lauren M Sparks
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, P. O. Box 616, 6200MD, Maastricht, the Netherlands
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, FL, USA
| | - Anne Gemmink
- Department of Human Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, the Netherlands
| | - Esther Phielix
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, P. O. Box 616, 6200MD, Maastricht, the Netherlands
| | - Madeleen Bosma
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, P. O. Box 616, 6200MD, Maastricht, the Netherlands
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Gert Schaart
- Department of Human Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, the Netherlands
| | - Esther Moonen-Kornips
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, P. O. Box 616, 6200MD, Maastricht, the Netherlands
| | - Johanna A Jörgensen
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, P. O. Box 616, 6200MD, Maastricht, the Netherlands
| | - Emmani B M Nascimento
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, P. O. Box 616, 6200MD, Maastricht, the Netherlands
| | - Matthijs K C Hesselink
- Department of Human Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, the Netherlands
| | - Patrick Schrauwen
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, P. O. Box 616, 6200MD, Maastricht, the Netherlands
| | - Joris Hoeks
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, P. O. Box 616, 6200MD, Maastricht, the Netherlands.
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Schlabritz-Loutsevitch NE, Comuzzie AG, Mahaney MM, Hubbard GB, Dick EJ, Kocak M, Gupta S, Carrillo M, Schenone M, Postlethwaite A, Slominski A. Serum Vitamin D Concentrations in Baboons (Papio spp.) during Pregnancy and Obesity. Comp Med 2016; 66:137-42. [PMID: 27053568 PMCID: PMC4825963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 10/08/2015] [Accepted: 10/11/2015] [Indexed: 06/05/2023]
Abstract
Obesity is associated with vitamin D deficiency, which can lead to serious problems during pregnancy. However, the mechanisms of the deficiency and guidelines for vitamin D supplementation during pregnancy are not established yet, and variations in environmental exposures combined with the difficulties of performing research in pregnant women are obstacles in the evaluation of vitamin D metabolism. Baboons (Papio spp.) are an excellent, well-established model for reproductive research and represent a unique opportunity to study vitamin D metabolism in a controlled environment. This study used secondary data and specimen analysis as well as a novel experimental design to evaluate pregnant and nonpregnant baboons that were or were not exposed to sunlight while they were obese and after weight reduction. Daily D3 intake was 71% higher in nonpregnant obese baboons than in their nonobese counterparts, but serum vitamin D concentrations did not differ between these populations. In addition, serum 25-hydroxyvitamin D concentrations correlated negatively with the obesity index. This report is the first to show the effect of obesity and pregnancy on vitamin D concentrations in a NHP population. These data underline the importance of adequate vitamin D supplementation in obese animals.
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Affiliation(s)
| | - Anthony G Comuzzie
- Departments of Genetics, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | | | - Gene B Hubbard
- Department of Pathology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Edward J Dick
- Departments of Pathology, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Mehmet Kocak
- Division of Biostatistics, Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, USA
| | - Sonali Gupta
- Department of Obstetrics and Gynecology; University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Maira Carrillo
- Texas Tech University HSC School of Medicine at the Permian Basin, Odessa, Texas
| | - Mauro Schenone
- Department of Obstetrics and Gynecology; University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Arnold Postlethwaite
- Division of Connective Tissue Diseases, Department of Medicine, University of Tennessee Health Science Center, and Department of Veterans Affairs Medical Center, Memphis, Tennessee, USA
| | - Andrzej Slominski
- Department of Dermatology and Pathology, VA Medical Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Jacome-Sosa M, Parks EJ, Bruno RS, Tasali E, Lewis GF, Schneeman BO, Rains TM. Postprandial Metabolism of Macronutrients and Cardiometabolic Risk: Recent Developments, Emerging Concepts, and Future Directions. Adv Nutr 2016; 7:364-74. [PMID: 26980820 PMCID: PMC4785471 DOI: 10.3945/an.115.010397] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Cardiovascular disease (CVD) is the leading cause of death in the United States. Although the role of habitual lifestyle factors such as physical activity and dietary patterns in increasing CVD risk has long been appreciated, less is known about how acute daily activities may cumulatively contribute to long-term disease risk. Here, the term acute refers to metabolic responses occurring in a short period of time after eating, and the goal of this article is to review recently identified stressors that can occur after meals and during the sleep-wake cycle to affect macronutrient metabolism. It is hypothesized that these events, when repeated on a regular basis, contribute to the observed long-term behavioral risks identified in population studies. In this regard, developments in research methods have supported key advancements in 3 fields of macronutrient metabolism. The first of these research areas is the focus on the immediate postmeal metabolism, spanning from early intestinal adsorptive events to the impact of incretin hormones on these events. The second topic is a focus on the importance of meal components on postprandial vasculature function. Finally, some of the most exciting advances are being made in understanding dysregulation in metabolism early in the day, due to insufficient sleep, that may affect subsequent processing of nutrients throughout the day. Key future research questions are highlighted which will lead to a better understanding of the relations between nocturnal, basal (fasting), and early postmeal events, and aid in the development of optimal sleep and targeted dietary patterns to reduce cardiometabolic risk.
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Affiliation(s)
- Miriam Jacome-Sosa
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO
| | - Elizabeth J Parks
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO;
| | - Richard S Bruno
- Human Nutrition Program, Department of Human Sciences, The Ohio State University, Columbus, OH
| | - Esra Tasali
- Department of Medicine, The University of Chicago, Chicago, IL
| | - Gary F Lewis
- Banting and Best Diabetes Center and Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, University of Toronto, Toronto, Canada
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20
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Broussard JL, Nelson MD, Kolka CM, Bediako IA, Paszkiewicz RL, Smith L, Szczepaniak EW, Stefanovski D, Szczepaniak LS, Bergman RN. Rapid development of cardiac dysfunction in a canine model of insulin resistance and moderate obesity. Diabetologia 2016; 59:197-207. [PMID: 26376797 PMCID: PMC5310691 DOI: 10.1007/s00125-015-3767-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 08/26/2015] [Indexed: 12/30/2022]
Abstract
AIMS/HYPOTHESIS The worldwide incidence of obesity and diabetes continues to rise at an alarming rate. A major cause of the morbidity and mortality associated with obesity and diabetes is heart disease, yet the mechanisms that lead to cardiovascular complications remain unclear. METHODS We performed cardiac MRI to assess left ventricular morphology and function during the development of moderate obesity and insulin resistance in a well-established canine model (n = 26). To assess the influence of dietary fat composition, we randomised animals to a traditional lard diet (rich in saturated and monounsaturated fat; n = 12), a salmon oil diet (rich in polyunsaturated fat; n = 8) or a control diet (n = 6). RESULTS High-fat feeding with lard increased body weight and fasting insulin and markedly reduced insulin sensitivity. Lard feeding also significantly reduced left ventricular function, evidenced by a worsening of circumferential strain and impairment in left ventricular torsion. High-fat feeding with salmon oil increased body weight; however, salmon oil feeding did not impair insulin sensitivity or cardiac function. CONCLUSIONS/INTERPRETATION These data emphasise the importance of dietary fat composition on both metabolic and cardiac function, and have important implications for the relationship between diet and health.
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Affiliation(s)
- Josiane L Broussard
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Michael D Nelson
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Cathryn M Kolka
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Isaac Asare Bediako
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Rebecca L Paszkiewicz
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Laura Smith
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Edward W Szczepaniak
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Darko Stefanovski
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Lidia S Szczepaniak
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA.
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21
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Broussard JL, Kolka CM, Castro AVB, Asare Bediako I, Paszkiewicz RL, Szczepaniak EW, Szczepaniak LS, Knutson KL, Kim SP, Bergman RN. Elevated nocturnal NEFA are an early signal for hyperinsulinaemic compensation during diet-induced insulin resistance in dogs. Diabetologia 2015; 58:2663-70. [PMID: 26254577 PMCID: PMC4591216 DOI: 10.1007/s00125-015-3721-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Accepted: 07/14/2015] [Indexed: 12/11/2022]
Abstract
AIMS/HYPOTHESIS A normal consequence of increased energy intake and insulin resistance is compensatory hyperinsulinaemia through increased insulin secretion and/or reduced insulin clearance. Failure of compensatory mechanisms plays a central role in the pathogenesis of type 2 diabetes mellitus; consequently, it is critical to identify in vivo signal(s) involved in hyperinsulinaemic compensation. We have previously reported that high-fat feeding leads to an increase in nocturnal NEFA concentration. We therefore designed this study to test the hypothesis that elevated nocturnal NEFA are an early signal for hyperinsulinaemic compensation for insulin resistance. METHODS Blood sampling was conducted in male dogs to determine 24 h profiles of NEFA at baseline and during high-fat feeding with and without acute nocturnal NEFA suppression using a partial A1 adenosine receptor agonist. RESULTS High-fat feeding increased nocturnal NEFA and reduced insulin sensitivity, effects countered by an increase in acute insulin response to glucose (AIR(g)). Pharmacological NEFA inhibition after 8 weeks of high-fat feeding lowered NEFA to baseline levels and reduced AIR(g) with no effect on insulin sensitivity. A significant relationship emerged between nocturnal NEFA levels and AIR(g). This relationship indicates that the hyperinsulinaemic compensation induced in response to high-fat feeding was prevented when the nocturnal NEFA pattern was returned to baseline. CONCLUSIONS/INTERPRETATION Elevated nocturnal NEFA are an important signal for hyperinsulinaemic compensation during diet-induced insulin resistance.
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Affiliation(s)
- Josiane L Broussard
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA.
| | - Cathryn M Kolka
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Ana V B Castro
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Isaac Asare Bediako
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Rebecca L Paszkiewicz
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Edward W Szczepaniak
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Lidia S Szczepaniak
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | | | - Stella P Kim
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Richard N Bergman
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
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22
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Kolka CM, Richey JM, Castro AVB, Broussard JL, Ionut V, Bergman RN. Lipid-induced insulin resistance does not impair insulin access to skeletal muscle. Am J Physiol Endocrinol Metab 2015; 308:E1001-9. [PMID: 25852002 PMCID: PMC4451289 DOI: 10.1152/ajpendo.00015.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 04/03/2015] [Indexed: 11/22/2022]
Abstract
Elevated plasma free fatty acids (FFA) induce insulin resistance in skeletal muscle. Previously, we have shown that experimental insulin resistance induced by lipid infusion prevents the dispersion of insulin through the muscle, and we hypothesized that this would lead to an impairment of insulin moving from the plasma to the muscle interstitium. Thus, we infused lipid into our anesthetized canine model and measured the appearance of insulin in the lymph as a means to sample muscle interstitium under hyperinsulinemic euglycemic clamp conditions. Although lipid infusion lowered the glucose infusion rate and induced both peripheral and hepatic insulin resistance, we were unable to detect an impairment of insulin access to the lymph. Interestingly, despite a significant, 10-fold increase in plasma FFA, we detected little to no increase in free fatty acids or triglycerides in the lymph after lipid infusion. Thus, we conclude that experimental insulin resistance induced by lipid infusion does not reduce insulin access to skeletal muscle under clamp conditions. This would suggest that the peripheral insulin resistance is likely due to reduced cellular sensitivity to insulin in this model, and yet we did not detect a change in the tissue microenvironment that could contribute to cellular insulin resistance.
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Affiliation(s)
- Cathryn M Kolka
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Joyce M Richey
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Ana Valeria B Castro
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Josiane L Broussard
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Viorica Ionut
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Richard N Bergman
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California
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23
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Broussard JL, Chapotot F, Abraham V, Day A, Delebecque F, Whitmore HR, Tasali E. Sleep restriction increases free fatty acids in healthy men. Diabetologia 2015; 58:791-8. [PMID: 25702040 PMCID: PMC4358810 DOI: 10.1007/s00125-015-3500-4] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Accepted: 12/22/2014] [Indexed: 02/03/2023]
Abstract
AIMS/HYPOTHESIS Sleep loss is associated with insulin resistance and an increased risk for type 2 diabetes, yet underlying mechanisms are not understood. Elevation of circulating non-esterified (i.e. free) fatty acid (NEFA) concentrations can lead to insulin resistance and plays a central role in the development of metabolic diseases. Circulating NEFA in healthy individuals shows a marked diurnal variation with maximum levels occurring at night, yet the impact of sleep loss on NEFA levels across the 24 h cycle remains unknown. We hypothesised that sleep restriction would alter hormones that are known to stimulate lipolysis and lead to an increase in NEFA levels. METHODS We studied 19 healthy young men under controlled laboratory conditions with four consecutive nights of 8.5 h in bed (normal sleep) and 4.5 h in bed (sleep restriction) in randomised order. The 24 h blood profiles of NEFA, growth hormone (GH), noradrenaline (norepinephrine), cortisol, glucose and insulin were simultaneously assessed. Insulin sensitivity was estimated by a frequently sampled intravenous glucose tolerance test. RESULTS Sleep restriction relative to normal sleep resulted in increased NEFA levels during the nocturnal and early-morning hours. The elevation in NEFA was related to prolonged nocturnal GH secretion and higher early-morning noradrenaline levels. Insulin sensitivity was decreased after sleep restriction and the reduction in insulin sensitivity was correlated with the increase in nocturnal NEFA levels. CONCLUSIONS/INTERPRETATION Sleep restriction in healthy men results in increased nocturnal and early-morning NEFA levels, which may partly contribute to insulin resistance and the elevated diabetes risk associated with sleep loss.
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Affiliation(s)
- Josiane L Broussard
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, THA E104, Los Angeles, CA, 90048, USA,
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24
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Jiang S, Minter LC, Stratton SA, Yang P, Abbas HA, Akdemir ZC, Pant V, Post S, Gagea M, Lee RG, Lozano G, Barton MC. TRIM24 suppresses development of spontaneous hepatic lipid accumulation and hepatocellular carcinoma in mice. J Hepatol 2015; 62:371-9. [PMID: 25281858 PMCID: PMC4772153 DOI: 10.1016/j.jhep.2014.09.026] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Revised: 08/25/2014] [Accepted: 09/22/2014] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Aberrantly high expression of TRIM24 occurs in human cancers, including hepatocellular carcinoma. In contrast, TRIM24 in the mouse is reportedly a liver-specific tumour suppressor. To address this dichotomy and to uncover direct regulatory functions of TRIM24 in vivo, we developed a new mouse model that lacks expression of all Trim24 isoforms, as the previous model expressed normal levels of Trim24 lacking only exon 4. METHODS To produce germline-deleted Trim24(dlE1) mice, deletion of the promoter and exon 1 of Trim24 was induced in Trim24(LoxP) mice by crossing with a zona pellucida 3-Cre line for global deletion. Liver-specific deletion (Trim24(hep)) was achieved by crossing with an albumin-Cre line. Phenotypic analyses were complemented by protein, gene-specific and global RNA expression analyses and quantitative chromatin immunoprecipitation. RESULTS Global loss of Trim24 disrupted hepatic homeostasis in 100% of mice with highly significant, decreased expression of oxidation/reduction, steroid, fatty acid, and lipid metabolism genes, as well as increased expression of genes involved in unfolded protein response, endoplasmic reticulum stress and cell cycle pathways. Trim24(dlE1/dlE1) mice have markedly depleted visceral fat and, like Trim24(hep/hep) mice, spontaneously develop hepatic lipid-filled lesions, steatosis, hepatic injury, fibrosis and hepatocellular carcinoma. CONCLUSIONS TRIM24, an epigenetic co-regulator of transcription, directly and indirectly represses hepatic lipid accumulation, inflammation, fibrosis and damage in the murine liver. Complete loss of Trim24 offers a model of human non-alcoholic fatty liver disease, steatosis, fibrosis and development of hepatocellular carcinoma in the absence of high-fat diet or obesity.
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Affiliation(s)
- Shiming Jiang
- Department of Biochemistry and Molecular Biology, UT MD Anderson Cancer Center, Houston, TX,Center for Stem Cell and Developmental Biology, UT MD Anderson Cancer Center, Houston, TX,Center for Cancer Epigenetics, UT MD Anderson Cancer Center, Houston, TX
| | - Lindsey Cauthen Minter
- Department of Biochemistry and Molecular Biology, UT MD Anderson Cancer Center, Houston, TX,Center for Stem Cell and Developmental Biology, UT MD Anderson Cancer Center, Houston, TX,Center for Cancer Epigenetics, UT MD Anderson Cancer Center, Houston, TX,Graduate program in Genes and Development, University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX
| | - Sabrina A. Stratton
- Department of Biochemistry and Molecular Biology, UT MD Anderson Cancer Center, Houston, TX,Center for Stem Cell and Developmental Biology, UT MD Anderson Cancer Center, Houston, TX,Center for Cancer Epigenetics, UT MD Anderson Cancer Center, Houston, TX
| | - Peirong Yang
- Department of Genetics, UT MD Anderson Cancer Center, Houston, TX
| | - Hussein A. Abbas
- Department of Genetics, UT MD Anderson Cancer Center, Houston, TX,Graduate program in Genes and Development, University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX
| | - Zeynep Coban Akdemir
- Department of Biochemistry and Molecular Biology, UT MD Anderson Cancer Center, Houston, TX,Center for Stem Cell and Developmental Biology, UT MD Anderson Cancer Center, Houston, TX,Center for Cancer Epigenetics, UT MD Anderson Cancer Center, Houston, TX,Graduate program in Genes and Development, University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX
| | - Vinod Pant
- Department of Genetics, UT MD Anderson Cancer Center, Houston, TX
| | - Sean Post
- Department of Leukemia, UT MD Anderson Cancer Center, Houston, TX
| | - Mihai Gagea
- Department of Veterinary Medicine and Surgery, UT MD Anderson Cancer Center, Houston TX
| | | | - Guillermina Lozano
- Department of Genetics, UT MD Anderson Cancer Center, Houston, TX,Graduate program in Genes and Development, University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX
| | - Michelle Craig Barton
- Department of Biochemistry and Molecular Biology, UT MD Anderson Cancer Center, Houston, TX, USA; Center for Stem Cell and Developmental Biology, UT MD Anderson Cancer Center, Houston, TX, USA; Center for Cancer Epigenetics, UT MD Anderson Cancer Center, Houston, TX, USA; Graduate Program in Genes and Development, University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, USA.
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25
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Dubé JJ, Coen PM, DiStefano G, Chacon AC, Helbling NL, Desimone ME, Stafanovic-Racic M, Hames KC, Despines AA, Toledo FGS, Goodpaster BH. Effects of acute lipid overload on skeletal muscle insulin resistance, metabolic flexibility, and mitochondrial performance. Am J Physiol Endocrinol Metab 2014; 307:E1117-24. [PMID: 25352435 PMCID: PMC4269675 DOI: 10.1152/ajpendo.00257.2014] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We hypothesized that acute lipid-induced insulin resistance would be attenuated in high-oxidative muscle of lean trained (LT) endurance athletes due to their enhanced metabolic flexibility and mitochondrial capacity. Lean sedentary (LS), obese sedentary (OS), and LT participants completed two hyperinsulinemic euglycemic clamp studies with and without (glycerol control) the coinfusion of Intralipid. Metabolic flexibility was measured by indirect calorimetry as the oxidation of fatty acids and glucose during fasted and insulin-stimulated conditions, the latter with and without lipid oversupply. Muscle biopsies were obtained for mitochondrial and insulin-signaling studies. During hyperinsulinemia without lipid, glucose infusion rate (GIR) was lowest in OS due to lower rates of nonoxidative glucose disposal (NOGD), whereas state 4 respiration was increased in all groups. Lipid infusion reduced GIR similarly in all subjects and reduced state 4 respiration. However, in LT subjects, fat oxidation was higher with lipid oversupply, and although glucose oxidation was reduced, NOGD was better preserved compared with LS and OS subjects. Mitochondrial performance was positively associated with better NOGD and insulin sensitivity in both conditions. We conclude that enhanced mitochondrial performance with exercise is related to better metabolic flexibility and insulin sensitivity in response to lipid overload.
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Affiliation(s)
- John J Dubé
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania and
| | - Paul M Coen
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Sanford/Burnham Medical Research Institute, Orlando, Florida
| | - Giovanna DiStefano
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania and
| | - Alexander C Chacon
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania and
| | - Nicole L Helbling
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania and
| | - Marisa E Desimone
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania and
| | - Maja Stafanovic-Racic
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania and
| | - Kazanna C Hames
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania and
| | - Alex A Despines
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania and
| | - Frederico G S Toledo
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania and
| | - Bret H Goodpaster
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Sanford/Burnham Medical Research Institute, Orlando, Florida
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26
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Fealy CE, Mulya A, Lai N, Kirwan JP. Exercise training decreases activation of the mitochondrial fission protein dynamin-related protein-1 in insulin-resistant human skeletal muscle. J Appl Physiol (1985) 2014; 117:239-45. [PMID: 24947026 PMCID: PMC4122691 DOI: 10.1152/japplphysiol.01064.2013] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 06/12/2014] [Indexed: 02/03/2023] Open
Abstract
Defects in mitochondrial dynamics, the processes of fission, fusion, and mitochondrial autophagy, may contribute to metabolic disease including type 2 diabetes. Dynamin-related protein-1 (Drp1) is a GTPase protein that plays a central role in mitochondrial fission. We hypothesized that aerobic exercise training would decrease Drp1 Ser(616) phosphorylation and increase fat oxidation and insulin sensitivity in obese (body mass index: 34.6 ± 0.8 kg/m(2)) insulin-resistant adults. Seventeen subjects performed supervised exercise for 60 min/day, 5 days/wk at 80-85% of maximal heart rate for 12 wk. Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp, and fat oxidation was determined by indirect calorimetry. Skeletal muscle biopsies were obtained from the vastus lateralis muscle before and after the 12-wk program. The exercise intervention increased insulin sensitivity 2.1 ± 0.2-fold (P < 0.01) and fat oxidation 1.3 ± 0.3-fold (P < 0.01). Phosphorylation of Drp1 at Ser(616) was decreased (pre vs. post: 0.81 ± 0.15 vs. 0.58 ± 0.14 arbitrary units; P < 0.05) following the intervention. Furthermore, reductions in Drp1 Ser(616) phosphorylation were negatively correlated with increases in fat oxidation (r = -0.58; P < 0.05) and insulin sensitivity (rho = -0.52; P < 0.05). We also examined expression of genes related to mitochondrial dynamics. Dynamin1-like protein (DNM1L; P < 0.01), the gene that codes for Drp1, and Optic atrophy 1 (OPA1; P = 0.05) were significantly upregulated following the intervention, while there was a trend towards an increase in expression of both mitofusin protein MFN1 (P = 0.08) and MFN2 (P = 0.07). These are the first data to suggest that lifestyle-mediated improvements in substrate metabolism and insulin sensitivity in obese insulin-resistant adults may be regulated through decreased activation of the mitochondrial fission protein Drp1.
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Affiliation(s)
- Ciaran E Fealy
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; Department of Biomedical Sciences, Kent State University, Kent, Ohio
| | - Anny Mulya
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; Metabolic Translational Research Center, Cleveland Clinic, Cleveland, Ohio; and
| | - Nicola Lai
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
| | - John P Kirwan
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; Metabolic Translational Research Center, Cleveland Clinic, Cleveland, Ohio; and
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27
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Daniele G, Eldor R, Merovci A, Clarke GD, Xiong J, Tripathy D, Taranova A, Abdul-Ghani M, DeFronzo RA. Chronic reduction of plasma free fatty acid improves mitochondrial function and whole-body insulin sensitivity in obese and type 2 diabetic individuals. Diabetes 2014; 63:2812-20. [PMID: 24353180 PMCID: PMC4113069 DOI: 10.2337/db13-1130] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Insulin resistance and dysregulation of free fatty acid (FFA) metabolism are core defects in type 2 diabetic (T2DM) and obese normal glucose tolerant (NGT) individuals. Impaired muscle mitochondrial function (reduced ATP synthesis) also has been described in insulin-resistant T2DM and obese subjects. We examined whether reduction in plasma FFA concentration with acipimox improved ATP synthesis rate and altered reactive oxygen species (ROS) production. Eleven NGT obese and 11 T2DM subjects received 1) OGTT, 2) euglycemic insulin clamp with muscle biopsy, and 3) (1)H-magnetic resonance spectroscopy of tibialis anterior muscle before and after acipimox (250 mg every 6 h for 12 days). ATP synthesis rate and ROS generation were measured in mitochondria isolated from muscle tissue ex vivo with chemoluminescence and fluorescence techniques, respectively. Acipimox 1) markedly reduced the fasting plasma FFA concentration and enhanced suppression of plasma FFA during oral glucose tolerance tests and insulin clamp in obese NGT and T2DM subjects and 2) enhanced insulin-mediated muscle glucose disposal and suppression of hepatic glucose production. The improvement in insulin sensitivity was closely correlated with the decrease in plasma FFA in obese NGT (r = 0.81) and T2DM (r = 0.76) subjects (both P < 0.001). Mitochondrial ATP synthesis rate increased by >50% in both obese NGT and T2DM subjects and was strongly correlated with the decrease in plasma FFA and increase in insulin-mediated glucose disposal (both r > 0.70, P < 0.001). Production of ROS did not change after acipimox. Reduction in plasma FFA in obese NGT and T2DM individuals improves mitochondrial ATP synthesis rate, indicating that the mitochondrial defect in insulin-resistant individuals is, at least in part, reversible.
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Affiliation(s)
- Giuseppe Daniele
- Division of Diabetes, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Roy Eldor
- Division of Diabetes, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Aurora Merovci
- Division of Diabetes, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Geoffrey D Clarke
- Division of Diabetes, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Juan Xiong
- Division of Diabetes, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Devjit Tripathy
- Division of Diabetes, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Anna Taranova
- Division of Diabetes, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Muhammad Abdul-Ghani
- Division of Diabetes, University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - Ralph A DeFronzo
- Division of Diabetes, University of Texas Health Science Center at San Antonio, San Antonio, TX
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28
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Fisher-Wellman KH, Weber TM, Cathey BL, Brophy PM, Gilliam LA, Kane CL, Maples JM, Gavin TP, Houmard JA, Neufer PD. Mitochondrial respiratory capacity and content are normal in young insulin-resistant obese humans. Diabetes 2014; 63:132-41. [PMID: 23974920 PMCID: PMC3868052 DOI: 10.2337/db13-0940] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Considerable debate exists about whether alterations in mitochondrial respiratory capacity and/or content play a causal role in the development of insulin resistance during obesity. The current study was undertaken to determine whether such alterations are present during the initial stages of insulin resistance in humans. Young (∼23 years) insulin-sensitive lean and insulin-resistant obese men and women were studied. Insulin resistance was confirmed through an intravenous glucose tolerance test. Measures of mitochondrial respiratory capacity and content as well as H(2)O(2) emitting potential and the cellular redox environment were performed in permeabilized myofibers and primary myotubes prepared from vastus lateralis muscle biopsy specimens. No differences in mitochondrial respiratory function or content were observed between lean and obese subjects, despite elevations in H(2)O(2) emission rates and reductions in cellular glutathione. These findings were apparent in permeabilized myofibers as well as in primary myotubes. The results suggest that reductions in mitochondrial respiratory capacity and content are not required for the initial manifestation of peripheral insulin resistance.
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Affiliation(s)
- Kelsey H. Fisher-Wellman
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC
- Department of Physiology, East Carolina University, Greenville, NC
| | - Todd M. Weber
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC
- Department of Kinesiology, East Carolina University, Greenville, NC
| | - Brook L. Cathey
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC
- Department of Physiology, East Carolina University, Greenville, NC
| | - Patricia M. Brophy
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC
- Department of Physiology, East Carolina University, Greenville, NC
| | - Laura A.A. Gilliam
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC
- Department of Physiology, East Carolina University, Greenville, NC
| | - Constance L. Kane
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC
- Department of Physiology, East Carolina University, Greenville, NC
| | - Jill M. Maples
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC
- Department of Kinesiology, East Carolina University, Greenville, NC
| | - Timothy P. Gavin
- Department of Health and Kinesiology, Purdue University, West Lafayette, IN
| | - Joseph A. Houmard
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC
- Department of Physiology, East Carolina University, Greenville, NC
- Department of Kinesiology, East Carolina University, Greenville, NC
| | - P. Darrell Neufer
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC
- Department of Physiology, East Carolina University, Greenville, NC
- Department of Kinesiology, East Carolina University, Greenville, NC
- Corresponding author: P. Darrell Neufer,
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Phielix E, Meex R, Ouwens DM, Sparks L, Hoeks J, Schaart G, Moonen-Kornips E, Hesselink MK, Schrauwen P. High oxidative capacity due to chronic exercise training attenuates lipid-induced insulin resistance. Diabetes 2012; 61:2472-8. [PMID: 22787138 PMCID: PMC3447923 DOI: 10.2337/db11-1832] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Fat accumulation in skeletal muscle combined with low mitochondrial oxidative capacity is associated with insulin resistance (IR). Endurance-trained athletes, characterized by a high oxidative capacity, have elevated intramyocellular lipids, yet are highly insulin sensitive. We tested the hypothesis that a high oxidative capacity could attenuate lipid-induced IR. Nine endurance-trained (age = 23.4 ± 0.9 years; BMI = 21.2 ± 0.6 kg/m(2)) and 10 untrained subjects (age = 21.9 ± 0.9 years; BMI = 22.8 ± 0.6 kg/m(2)) were included and underwent a clamp with either infusion of glycerol or intralipid. Muscle biopsies were taken to perform high-resolution respirometry and protein phosphorylation/expression. Trained subjects had ~32% higher mitochondrial capacity and ~22% higher insulin sensitivity (P < 0.05 for both). Lipid infusion reduced insulin-stimulated glucose uptake by 63% in untrained subjects (P < 0.05), whereas this effect was blunted in trained subjects (29%, P < 0.05). In untrained subjects, lipid infusion reduced oxidative and nonoxidative glucose disposal (NOGD), whereas trained subjects were completely protected against lipid-induced reduction in NOGD, supported by dephosphorylation of glycogen synthase. We conclude that chronic exercise training attenuates lipid-induced IR and specifically attenuates the lipid-induced reduction in NOGD. Signaling data support the notion that high glucose uptake in trained subjects is maintained by shuttling glucose toward storage as glycogen.
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Affiliation(s)
- Esther Phielix
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Ruth Meex
- Department of Human Movement Sciences, NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University Medical Center, Maastricht, the Netherlands
| | - D. Margriet Ouwens
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Dusseldorf, Germany
| | - Lauren Sparks
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Joris Hoeks
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Gert Schaart
- Department of Human Movement Sciences, NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Esther Moonen-Kornips
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University Medical Center, Maastricht, the Netherlands
- Department of Human Movement Sciences, NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Matthijs K.C. Hesselink
- Department of Human Movement Sciences, NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Patrick Schrauwen
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University Medical Center, Maastricht, the Netherlands
- Corresponding author: Patrick Schrauwen,
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Role of mitochondrial function in insulin resistance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 942:215-34. [PMID: 22399424 DOI: 10.1007/978-94-007-2869-1_9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The obesity pandemic increases the prevalence of type 2 diabetes (DM2).DM2 develops when pancreatic β-cells fail and cannot compensate for the decrease in insulin sensitivity. How excessive caloric intake and weight gain cause insulin resistance has not completely been elucidated.Skeletal muscle is responsible for a major part of insulin stimulated whole-body glucose disposal and, hence, plays an important role in the pathogenesis of insulin resistance.It has been hypothesized that skeletal muscle mitochondrial dysfunction is involved in the accumulation of intramyocellular lipid metabolites leading to lipotoxicity and insulin resistance. However, findings on skeletal muscle mitochondrial function in relation to insulin resistance in human subjects are inconclusive. Differences in mitochondrial activity can be the result of several factors, including a reduced mitochondrial density, differences in insulin stimulated mitochondrial respiration, lower energy demand or reduced skeletal muscle perfusion, besides an intrinsic mitochondrial defect. The inconclusive results may be explained by the use of different techniques and study populations. Also, mitochondrial capacity is in far excess to meet energy requirements and therefore it may be questioned whether a reduced mitochondrial capacity limits mitochondrial fatty acid oxidation. Whether reduced mitochondrial function is causally related to insulin resistance or rather a consequence of the sedentary lifestyle remains to be elucidated.
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31
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Mitochondrial fission contributes to mitochondrial dysfunction and insulin resistance in skeletal muscle. Mol Cell Biol 2011; 32:309-19. [PMID: 22083962 DOI: 10.1128/mcb.05603-11] [Citation(s) in RCA: 452] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mitochondrial dysfunction in skeletal muscle has been implicated in the development of insulin resistance and type 2 diabetes. Considering the importance of mitochondrial dynamics in mitochondrial and cellular functions, we hypothesized that obesity and excess energy intake shift the balance of mitochondrial dynamics, further contributing to mitochondrial dysfunction and metabolic deterioration in skeletal muscle. First, we revealed that excess palmitate (PA), but not hyperglycemia, hyperinsulinemia, or elevated tumor necrosis factor alpha, induced mitochondrial fragmentation and increased mitochondrion-associated Drp1 and Fis1 in differentiated C2C12 muscle cells. This fragmentation was associated with increased oxidative stress, mitochondrial depolarization, loss of ATP production, and reduced insulin-stimulated glucose uptake. Both genetic and pharmacological inhibition of Drp1 attenuated PA-induced mitochondrial fragmentation, mitochondrial depolarization, and insulin resistance in C2C12 cells. Furthermore, we found smaller and shorter mitochondria and increased mitochondrial fission machinery in the skeletal muscle of mice with genetic obesity and those with diet-induced obesity. Inhibition of mitochondrial fission improved the muscle insulin signaling and systemic insulin sensitivity of obese mice. Our findings indicated that aberrant mitochondrial fission is causally associated with mitochondrial dysfunction and insulin resistance in skeletal muscle. Thus, disruption of mitochondrial dynamics may underlie the pathogenesis of muscle insulin resistance in obesity and type 2 diabetes.
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Zhang H, Zhang HM, Wu LP, Tan DX, Kamat A, Li YQ, Katz MS, Abboud HE, Reiter RJ, Zhang BX. Impaired mitochondrial complex III and melatonin responsive reactive oxygen species generation in kidney mitochondria of db/db mice. J Pineal Res 2011; 51:338-44. [PMID: 21615785 PMCID: PMC3165143 DOI: 10.1111/j.1600-079x.2011.00894.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We have previously demonstrated that melatonin, at pharmacological concentrations, causes rapid reactive oxygen species (ROS) generation at the antimycin-A sensitive site of mitochondrial complex III (MC-3). In the current work, we used this melatonin response to investigate the role of mitochondrial dysfunction in the development of diabetic nephropathy. We find that the development of diabetic nephropathy, as indicated by hyperfiltration and histopathological lesions in the kidney of db/db mice, is associated with diminished melatonin-induced ROS generation and MC-3 activity, indicating impaired MC-3 at the antimycin-A site. The MC-3 protein level in the renal mitochondria was equivalent in db/db and the nondiabetic db/m mice, whereas mitochondrial complex I (MC-1) protein was dramatically upregulated in the db/db mice. This differential regulation in mitochondrial complexes may alter the equilibrium of the electron transport in renal mitochondria and contribute to ROS overproduction. The study provides one mechanism of enhanced oxidative stress that may be involved in the pathogenesis of diabetic nephropathy in db/db mice.
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Affiliation(s)
- Hua Zhang
- Department of Geriatrics, K.K. Leung Brain Research Center, The Fourth Military Medical University, Xi’An, China
- Department of Medicine, University of Texas Health Science Center at San Antonio
| | - Hong-Mei Zhang
- Department of Medicine, University of Texas Health Science Center at San Antonio
- Clinical Oncology, Xijing Hospital, K.K. Leung Brain Research Center, The Fourth Military Medical University, Xi’An, China
| | - Li-Ping Wu
- Department of Geriatrics, K.K. Leung Brain Research Center, The Fourth Military Medical University, Xi’An, China
| | - Dun-Xian Tan
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio
| | - Amrita Kamat
- Department of Medicine, University of Texas Health Science Center at San Antonio
- Geriatric Research, Education and Clinical Center, South Texas Veterans Health Care System, Audie L. Murphy Division, San Antonio, Texas, USA
| | - Yun-Qing Li
- Department of Anatomy, Histology and Embryology, K.K. Leung Brain Research Center, The Fourth Military Medical University, Xi’An, China
| | - Michael S Katz
- Department of Medicine, University of Texas Health Science Center at San Antonio
- Geriatric Research, Education and Clinical Center, South Texas Veterans Health Care System, Audie L. Murphy Division, San Antonio, Texas, USA
| | - Hanna E Abboud
- Department of Medicine, University of Texas Health Science Center at San Antonio
| | - Russel J Reiter
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio
| | - Bin-Xian Zhang
- Department of Medicine, University of Texas Health Science Center at San Antonio
- Geriatric Research, Education and Clinical Center, South Texas Veterans Health Care System, Audie L. Murphy Division, San Antonio, Texas, USA
- Correspondence: Dr. Bin-Xian Zhang, Geriatric Research, Education and Clinical Center, STVHCS-ALMD, 7400 Merton Minter Blvd, San Antonio, TX 78229. Phone: 210-617-5197; Fax: 210-617-5312;
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33
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Brands M, Hoeks J, Sauerwein HP, Ackermans MT, Ouwens M, Lammers NM, van der Plas MN, Schrauwen P, Groen AK, Serlie MJ. Short-term increase of plasma free fatty acids does not interfere with intrinsic mitochondrial function in healthy young men. Metabolism 2011; 60:1398-405. [PMID: 21489571 DOI: 10.1016/j.metabol.2011.02.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 02/02/2011] [Accepted: 02/09/2011] [Indexed: 11/21/2022]
Abstract
Free fatty acid (FFA)- and obesity-induced insulin resistance has been associated with disturbed mitochondrial function. Elevated plasma FFA can impair insulin-induced increase of adenosine triphosphate synthesis and downregulate the expression of genes important in the biogenesis of mitochondria in human skeletal muscle. Whether FAs have a direct effect on intrinsic mitochondrial capacity remains to be established. Therefore, we measured ex vivo mitochondrial respiratory capacity in human skeletal muscle after exposure to hyperinsulinemia and high levels of plasma FFA. Nine healthy lean men were studied during a 6-hour hyperinsulinemic (600 pmol/L) euglycemic clamp with concomitant infusion of Intralipid (Fresensius Kabi Nederland, Den Bosch, the Netherlands) (FFA clamped at 0.5 mmol/L) or saline. Mitochondrial respiratory capacity was measured by high-resolution respirometry in permeabilized muscle fibers using an Oxygraph (OROBOROS Instruments, Innsbruck, Austria). Each participant served as his own control. Peripheral glucose uptake (rate of disappearance) was significantly lower during infusion of the lipid emulsion compared with the control saline infusion (68 μmol/kg·min [saline] vs 40 μmol/kg·min [lipid], P = .008). However, adenosine diphosphate-stimulated and maximal carbonylcyanide-4-(trifluoromethoxy)-phenylhydrazone-stimulated uncoupled respiration rates were not different in permeabilized skeletal muscle fibers after exposure to high levels of FFA compared with the control condition. We conclude that short-term elevation of FFA within the physiological range induces insulin resistance but does not affect intrinsic mitochondrial capacity in skeletal muscle in humans.
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MESH Headings
- Adult
- Biopsy
- Blood Glucose/metabolism
- Cell Respiration/drug effects
- Cell Respiration/physiology
- Fatty Acids, Nonesterified/blood
- Fatty Acids, Nonesterified/metabolism
- Fatty Acids, Nonesterified/pharmacology
- Glucose Clamp Technique
- Health
- Humans
- Insulin/blood
- Insulin Resistance/physiology
- Male
- Mitochondria, Muscle/drug effects
- Mitochondria, Muscle/metabolism
- Mitochondria, Muscle/physiology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiology
- Oxidation-Reduction/drug effects
- Time Factors
- Young Adult
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Affiliation(s)
- Myrte Brands
- Department of Endocrinology and Metabolism, Academic Medical Center Amsterdam, 1105 AZ Amsterdam, The Netherlands.
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34
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Szendroedi J, Phielix E, Roden M. The role of mitochondria in insulin resistance and type 2 diabetes mellitus. Nat Rev Endocrinol 2011; 8:92-103. [PMID: 21912398 DOI: 10.1038/nrendo.2011.138] [Citation(s) in RCA: 413] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Type 2 diabetes mellitus (T2DM) has been related to alterations of oxidative metabolism in insulin-responsive tissues. Overt T2DM can present with acquired or inherited reductions of mitochondrial oxidative phosphorylation capacity, submaximal ADP-stimulated oxidative phosphorylation and plasticity of mitochondria and/or lower mitochondrial content in skeletal muscle cells and potentially also in hepatocytes. Acquired insulin resistance is associated with reduced insulin-stimulated mitochondrial activity as the result of blunted mitochondrial plasticity. Hereditary insulin resistance is frequently associated with reduced mitochondrial activity at rest, probably due to diminished mitochondrial content. Lifestyle and pharmacological interventions can enhance the capacity for oxidative phosphorylation and mitochondrial content and improve insulin resistance in some (pre)diabetic cases. Various mitochondrial features can be abnormal but are not necessarily responsible for all forms of insulin resistance. Nevertheless, mitochondrial abnormalities might accelerate progression of insulin resistance and subsequent organ dysfunction via increased production of reactive oxygen species. This Review discusses the association between mitochondrial function and insulin sensitivity in various tissues, such as skeletal muscle, liver and heart, with a main focus on studies in humans, and addresses the effects of therapeutic strategies that affect mitochondrial function and insulin sensitivity.
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Affiliation(s)
- Julia Szendroedi
- Institute for Clinical Diabetology, German Diabetes Center, D-40225 Düsseldorf, Germany
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35
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Bibliography. Current world literature. Adrenal cortex. Curr Opin Endocrinol Diabetes Obes 2011; 18:231-3. [PMID: 21522003 DOI: 10.1097/med.0b013e3283457c7d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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36
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McConoughey SJ, Basso M, Niatsetskaya ZV, Sleiman SF, Smirnova NA, Langley BC, Mahishi L, Cooper AJL, Antonyak MA, Cerione RA, Li B, Starkov A, Chaturvedi RK, Beal MF, Coppola G, Geschwind DH, Ryu H, Xia L, Iismaa SE, Pallos J, Pasternack R, Hils M, Fan J, Raymond LA, Marsh JL, Thompson LM, Ratan RR. Inhibition of transglutaminase 2 mitigates transcriptional dysregulation in models of Huntington disease. EMBO Mol Med 2011; 2:349-70. [PMID: 20665636 PMCID: PMC3068019 DOI: 10.1002/emmm.201000084] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Caused by a polyglutamine expansion in the huntingtin protein, Huntington's disease leads to striatal degeneration via the transcriptional dysregulation of a number of genes, including those involved in mitochondrial biogenesis. Here we show that transglutaminase 2, which is upregulated in HD, exacerbates transcriptional dysregulation by acting as a selective corepressor of nuclear genes; transglutaminase 2 interacts directly with histone H3 in the nucleus. In a cellular model of HD, transglutaminase inhibition de-repressed two established regulators of mitochondrial function, PGC-1α and cytochrome c and reversed susceptibility of human HD cells to the mitochondrial toxin, 3-nitroproprionic acid; however, protection mediated by transglutaminase inhibition was not associated with improved mitochondrial bioenergetics. A gene microarray analysis indicated that transglutaminase inhibition normalized expression of not only mitochondrial genes but also 40% of genes that are dysregulated in HD striatal neurons, including chaperone and histone genes. Moreover, transglutaminase inhibition attenuated degeneration in a Drosophila model of HD and protected mouse HD striatal neurons from excitotoxicity. Altogether these findings demonstrate that selective TG inhibition broadly corrects transcriptional dysregulation in HD and defines a novel HDAC-independent epigenetic strategy for treating neurodegeneration.
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Hoeks J, van Herpen NA, Mensink M, Moonen-Kornips E, van Beurden D, Hesselink MKC, Schrauwen P. Prolonged fasting identifies skeletal muscle mitochondrial dysfunction as consequence rather than cause of human insulin resistance. Diabetes 2010; 59:2117-25. [PMID: 20573749 PMCID: PMC2927932 DOI: 10.2337/db10-0519] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Type 2 diabetes and insulin resistance have been associated with mitochondrial dysfunction, but it is debated whether this is a primary factor in the pathogenesis of the disease. To test the concept that mitochondrial dysfunction is secondary to the development of insulin resistance, we employed the unique model of prolonged fasting in humans. Prolonged fasting is a physiologic condition in which muscular insulin resistance develops in the presence of increased free fatty acid (FFA) levels, increased fat oxidation and low glucose and insulin levels. It is therefore anticipated that skeletal muscle mitochondrial function is maintained to accommodate increased fat oxidation unless factors secondary to insulin resistance exert negative effects on mitochondrial function. RESEARCH DESIGN AND METHODS While in a respiration chamber, twelve healthy males were subjected to a 60 h fast and a 60 h normal fed condition in a randomized crossover design. Afterward, insulin sensitivity was assessed using a hyperinsulinemic-euglycemic clamp, and mitochondrial function was quantified ex vivo in permeabilized muscle fibers using high-resolution respirometry. RESULTS Indeed, FFA levels were increased approximately ninefold after 60 h of fasting in healthy male subjects, leading to elevated intramuscular lipid levels and decreased muscular insulin sensitivity. Despite an increase in whole-body fat oxidation, we observed an overall reduction in both coupled state 3 respiration and maximally uncoupled respiration in permeabilized skeletal muscle fibers, which could not be explained by changes in mitochondrial density. CONCLUSIONS These findings confirm that the insulin-resistant state has secondary negative effects on mitochondrial function. Given the low insulin and glucose levels after prolonged fasting, hyperglycemia and insulin action per se can be excluded as underlying mechanisms, pointing toward elevated plasma FFA and/or intramuscular fat accumulation as possible causes for the observed reduction in mitochondrial capacity.
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Affiliation(s)
- Joris Hoeks
- Department of Human Biology, School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, Maastricht, the Netherlands.
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38
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Abstract
The widespread epidemics of obesity and type 2 diabetes mellitus (T2DM) suggest that both conditions are closely linked. An increasing body of evidence has shifted our view of adipose tissue from a passive energy depot to a dynamic "endocrine organ" that tightly regulates nutritional balance by means of a complex crosstalk of adipocytes with their microenvironment. Dysfunctional adipose tissue, particularly as observed in obesity, is characterized by adipocyte hypertrophy, macrophage infiltration, impaired insulin signaling, and insulin resistance. The result is the release of a host of inflammatory adipokines and excessive amounts of free fatty acids that promote ectopic fat deposition and lipotoxicity in muscle, liver, and pancreatic beta cells. This review focuses on recent work on how glucose homeostasis is profoundly altered by distressed adipose tissue. A better understanding of this relationship offers the best chance for early intervention strategies aimed at preventing the burden of T2DM.
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Affiliation(s)
- Kenneth Cusi
- The University of Texas Health Science Center at San Antonio, Diabetes Division, Room 3.380S, 7703 Floyd Curl Drive, San Antonio, TX 78284-3900, USA.
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39
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Brehm A, Krssák M, Schmid AI, Nowotny P, Waldhäusl W, Roden M. Acute elevation of plasma lipids does not affect ATP synthesis in human skeletal muscle. Am J Physiol Endocrinol Metab 2010; 299:E33-8. [PMID: 20442322 DOI: 10.1152/ajpendo.00756.2009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Prolonged elevation of plasma triglycerides and free fatty acids (FFA) reduces insulin-stimulated glucose disposal and myocellular flux through ATP synthase (fATPase). However, the early effects of lipids per se on fATPase are as yet unclear. Thus, this study examined glucose disposal and fATPase during 3 h of FFA elevation in the presence of low plasma insulinemia. Euglycemic pancreatic clamps with low-dose insulin supplementation (6 mU.m body surface area(-2).min(-1)) were performed in eight healthy men with (LIP) or without (CON) lipid infusion to measure whole body glucose disposal. (31)P/(1)H magnetic resonance spectroscopy of calf muscle was applied to quantify fATPase and concentrations of glucose 6-phosphate (G6P), inorganic phosphate (P(i)), phosphocreatine (PCr), ADP, pH, and IMCL before and during the clamps. Lipid infusion increased plasma FFA approximately twofold and decreased glucose disposal by approximately 50% (110-180 min: LIP 0.87 +/- 0.45 vs. CON 1.75 +/- 0.42 mg.kg(-1).min(-1), P = 0.002; means +/- SD). Intramyocellular G6P tended to rise only under control conditions, whereas PCr, ADP, pH, and IMCL remained unchanged from fasting in LIP and CON. Although P(i) concentrations increased by approximately 18%, fATPase remained unchanged from fasting during the clamps (LIP 10.2 +/- 2.2 vs. CON 10.5 +/- 2.6 micromol.g muscle(-1).min(-1), P = not significant). We conclude that 3 h of lipid elevation fail to affect ATP synthesis despite marked reduction of whole body glucose uptake. This suggests that lipid-induced insulin resistance results primarily from mechanisms decreasing glucose uptake rather than from direct interference of fatty acid metabolites with mitochondrial function.
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Affiliation(s)
- A Brehm
- First Medical Department, Hanusch Hospital, Vienna, Austria
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40
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Fillmore N, Jacobs DL, Mills DB, Winder WW, Hancock CR. Chronic AMP-activated protein kinase activation and a high-fat diet have an additive effect on mitochondria in rat skeletal muscle. J Appl Physiol (1985) 2010; 109:511-20. [PMID: 20522731 DOI: 10.1152/japplphysiol.00126.2010] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Factors that stimulate mitochondrial biogenesis in skeletal muscle include AMP-activated protein kinase (AMPK), calcium, and circulating free fatty acids (FFAs). Chronic treatment with either 5-aminoimidazole-4-carboxamide riboside (AICAR), a chemical activator of AMPK, or increasing circulating FFAs with a high-fat diet increases mitochondria in rat skeletal muscle. The purpose of this study was to determine whether the combination of chronic chemical activation of AMPK and high-fat feeding would have an additive effect on skeletal muscle mitochondria levels. We treated Wistar male rats with a high-fat diet (HF), AICAR injections (AICAR), or a high-fat diet and AICAR injections (HF + AICAR) for 6 wk. At the end of the treatment period, markers of mitochondrial content were examined in white quadriceps, red quadriceps, and soleus muscles, predominantly composed of unique muscle-fiber types. In white quadriceps, there was a cumulative effect of treatments on long-chain acyl-CoA dehydrogenase, cytochrome c, and peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) protein, as well as on citrate synthase and beta-hydroxyacyl-CoA dehydrogenase (beta-HAD) activity. In contrast, no additive effect was noted in the soleus, and in the red quadriceps only beta-HAD activity increased additively. The additive increase of mitochondrial markers observed in the white quadriceps may be explained by a combined effect of two separate mechanisms: high-fat diet-induced posttranscriptional increase in PGC-1alpha protein and AMPK-mediated increase in PGC-1alpha protein via a transcriptional mechanism. These data show that chronic chemical activation of AMPK and a high-fat diet have a muscle type specific additive effect on markers of fatty acid oxidation, the citric acid cycle, the electron transport chain, and transcriptional regulation.
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Affiliation(s)
- Natasha Fillmore
- Department of Physiology and Developmental Biology, Birgham Young University, Provo, UT 84602, USA
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Abstract
Type 2 diabetes mellitus (T2DM) is characterized by defects in insulin action and insulin secretion. Although insulin resistance manifests early during the prediabetic state, a failing beta-cell function unable to overcome insulin resistance at target tissues determines the onset of T2DM. This review focuses on recent advances in the molecular mechanisms of insulin resistance and beta-cell dysfunction. The role of mitochondrial dysfunction, impaired regulation of the enteroinsular axis, and endoplasmic reticulum stress are currently the subjects of intensive research. In addition, the adipose tissue has emerged as a major endocrine organ that secretes a growing list of adipocytokines with diverse central and peripheral metabolic effects. The role of a growing number of candidate genes and transcription factors regulating insulin action and secretion is also discussed.
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Affiliation(s)
- Devjit Tripathy
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
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42
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Pathogenesis of insulin resistance in skeletal muscle. J Biomed Biotechnol 2010; 2010:476279. [PMID: 20445742 PMCID: PMC2860140 DOI: 10.1155/2010/476279] [Citation(s) in RCA: 364] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 01/20/2010] [Indexed: 12/16/2022] Open
Abstract
Insulin resistance in skeletal muscle is manifested by decreased insulin-stimulated glucose uptake and results from impaired insulin signaling and multiple post-receptor intracellular defects including impaired glucose transport, glucose phosphorylation, and reduced glucose oxidation and glycogen synthesis. Insulin resistance is a core defect in type 2 diabetes, it is also associated with obesity and the metabolic syndrome. Dysregulation of fatty acid metabolism plays a pivotal role in the pathogenesis of insulin resistance in skeletal muscle. Recent studies have reported a mitochondrial defect in oxidative phosphorylation in skeletal muscle in variety of insulin resistant states. In this review, we summarize the cellular and molecular defects that contribute to the development of insulin resistance in skeletal muscle.
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