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Lovell AJ, Hoecht EM, Hucik B, Cervone DT, Dyck DJ. The effects of diet and chronic exercise on skeletal muscle ghrelin response. Metabol Open 2022; 14:100182. [PMID: 35340718 PMCID: PMC8942827 DOI: 10.1016/j.metop.2022.100182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 03/14/2022] [Accepted: 03/16/2022] [Indexed: 11/20/2022] Open
Abstract
Background Recent findings indicate that ghrelin, particularly the unacylated form (UnAG), acutely stimulates skeletal muscle fatty acid oxidation (FAO) and can preserve insulin signaling and insulin-stimulated glucose uptake in the presence of high concentrations of saturated fatty acids. However, we recently reported that the stimulatory effect of ghrelin on FAO and subsequent ability to protect insulin stimulated glucose uptake was lost following 6-weeks (6w) of chronic high fat feeding. In the current study we examined the effects of both short-term 5 day (5d) and chronic 6w high-fat diet (HFD) on muscle ghrelin response, and whether exercise training could prevent the development of muscle ghrelin resistance with 6w of HFD Methods and Results Soleus muscle strips were isolated from male rats to determine the direct effects of acylated (AG) and UnAG isoforms on FAO and glucose uptake. A 5d HFD did not alter the response of soleus muscle to AG or UnAG. Conversely, 6w of HFD was associated with a loss of ghrelin's ability to stimulate FAO and protect insulin stimulated glucose uptake. Muscle response to UnAG remained intact following the 6w HFD with chronic exercise training. Unexpectedly, muscle response to both AG and UnAG was also lost after 6w of low-fat diet (LFD) consumption. Protein content of the classic ghrelin receptor, GHS-R1a, was not affected by diet or training. Corticotropin-releasing hormone receptor-2 (CRF-2R) content, a putative receptor for ghrelin in muscle, was significantly decreased in soleus from 6w HFD-fed animals and increased following exercise training. This may explain the protection of UnAG response with training in HFD-fed rats but does not explain why ghrelin response was also lost in LFD-fed animals. Conclusions UnAG protects muscle glucose uptake during acute lipid oversupply, likely due to its ability to stimulate FAO. This effect is lost in 6w HFD-fed animals but protected with exercise training. Unexpectedly, ghrelin response was lost in 6w LFD-fed animals. The loss of ghrelin response in muscle with a LFD cannot be explained by a change in putative ghrelin receptor content. We believe that the sedentary nature of the animals is a major factor in the development of muscle ghrelin resistance and warrants further research. Ghrelin stimulates fatty acid oxidation in skeletal muscle. This stimulation is strongly associated with protection from acute fat overload. Prolonged sedentary behaviour and a high fat diet impair ghrelin's ability to stimulate fatty acid oxidation. Exercise training preserves ghrelin's positive effects on skeletal muscle.
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Błachnio-Zabielska AU, Roszczyc-Owsiejczuk K, Imierska M, Pogodzińska K, Rogalski P, Daniluk J, Zabielski P. CerS1 but Not CerS5 Gene Silencing, Improves Insulin Sensitivity and Glucose Uptake in Skeletal Muscle. Cells 2022; 11:206. [PMID: 35053322 PMCID: PMC8773817 DOI: 10.3390/cells11020206] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 12/31/2021] [Accepted: 01/05/2022] [Indexed: 12/11/2022] Open
Abstract
Skeletal muscle is perceived as a major tissue in glucose and lipid metabolism. High fat diet (HFD) lead to the accumulation of intramuscular lipids, including: long chain acyl-CoA, diacylglycerols, and ceramides. Ceramides are considered to be one of the most important lipid groups in the generation of skeletal muscle insulin resistance. So far, it has not been clearly established whether all ceramides adversely affect the functioning of the insulin pathway, or whether there are certain ceramide species that play a pivotal role in the induction of insulin resistance. Therefore, we designed a study in which the expression of CerS1 and CerS5 genes responsible for the synthesis of C18:0-Cer and C16:0-Cer, respectively, was locally silenced in the gastrocnemius muscle of HFD-fed mice through in vivo electroporation-mediated shRNA plasmids. Our study indicates that HFD feeding induced both, the systemic and skeletal muscle insulin resistance, which was accompanied by an increase in the intramuscular lipid levels, decreased activation of the insulin pathway and, consequently, a decrease in the skeletal muscle glucose uptake. CerS1 silencing leads to a reduction in C18:0-Cer content, with a subsequent increase in the activity of the insulin pathway, and an improvement in skeletal muscle glucose uptake. Such effects were not visible in case of CerS5 silencing, which indicates that the accumulation of C18:0-Cer plays a decisive role in the induction of skeletal muscle insulin resistance.
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Affiliation(s)
- Agnieszka U. Błachnio-Zabielska
- Department of Hygiene, Epidemiology and Metabolic Disorders, Medical University of Bialystok, Mickiewicza 2c, 15-089 Bialystok, Poland; (K.R.-O.); (M.I.); (K.P.)
| | - Kamila Roszczyc-Owsiejczuk
- Department of Hygiene, Epidemiology and Metabolic Disorders, Medical University of Bialystok, Mickiewicza 2c, 15-089 Bialystok, Poland; (K.R.-O.); (M.I.); (K.P.)
| | - Monika Imierska
- Department of Hygiene, Epidemiology and Metabolic Disorders, Medical University of Bialystok, Mickiewicza 2c, 15-089 Bialystok, Poland; (K.R.-O.); (M.I.); (K.P.)
| | - Karolina Pogodzińska
- Department of Hygiene, Epidemiology and Metabolic Disorders, Medical University of Bialystok, Mickiewicza 2c, 15-089 Bialystok, Poland; (K.R.-O.); (M.I.); (K.P.)
| | - Paweł Rogalski
- Department of Gastroenterology and Internal Medicine, Medical University of Bialystok, 15-089 Bialystok, Poland; (P.R.); (J.D.)
| | - Jarosław Daniluk
- Department of Gastroenterology and Internal Medicine, Medical University of Bialystok, 15-089 Bialystok, Poland; (P.R.); (J.D.)
| | - Piotr Zabielski
- Department of Medical Biology, Medical University of Bialystok, 15-089 Bialystok, Poland
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Bergman BC, Goodpaster BH. Exercise and Muscle Lipid Content, Composition, and Localization: Influence on Muscle Insulin Sensitivity. Diabetes 2020; 69:848-858. [PMID: 32312901 DOI: 10.2337/dbi18-0042] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/17/2020] [Indexed: 11/13/2022]
Abstract
Accumulation of lipid in skeletal muscle is thought to be related to the development of insulin resistance and type 2 diabetes. Initial work in this area focused on accumulation of intramuscular triglyceride; however, bioactive lipids such as diacylglycerols and sphingolipids are now thought to play an important role. Specific species of these lipids appear to be more negative toward insulin sensitivity than others. Adding another layer of complexity, localization of lipids within the cell appears to influence the relationship between these lipids and insulin sensitivity. This article summarizes how accumulation of total lipids, specific lipid species, and localization of lipids influence insulin sensitivity in humans. We then focus on how these aspects of muscle lipids are impacted by acute and chronic aerobic and resistance exercise training. By understanding how exercise alters specific species and localization of lipids, it may be possible to uncover specific lipids that most heavily impact insulin sensitivity.
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Tan-Chen S, Guitton J, Bourron O, Le Stunff H, Hajduch E. Sphingolipid Metabolism and Signaling in Skeletal Muscle: From Physiology to Physiopathology. Front Endocrinol (Lausanne) 2020; 11:491. [PMID: 32849282 PMCID: PMC7426366 DOI: 10.3389/fendo.2020.00491] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/22/2020] [Indexed: 12/14/2022] Open
Abstract
Sphingolipids represent one of the major classes of eukaryotic lipids. They play an essential structural role, especially in cell membranes where they also possess signaling properties and are capable of modulating multiple cell functions, such as apoptosis, cell proliferation, differentiation, and inflammation. Many sphingolipid derivatives, such as ceramide, sphingosine-1-phosphate, and ganglioside, have been shown to play many crucial roles in muscle under physiological and pathological conditions. This review will summarize our knowledge of sphingolipids and their effects on muscle fate, highlighting the role of this class of lipids in modulating muscle cell differentiation, regeneration, aging, response to insulin, and contraction. We show that modulating sphingolipid metabolism may be a novel and interesting way for preventing and/or treating several muscle-related diseases.
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Affiliation(s)
- Sophie Tan-Chen
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Paris, France
- Institut Hospitalo-Universitaire ICAN, Paris, France
| | - Jeanne Guitton
- Université Saclay, CNRS UMR 9197, Institut des Neurosciences Paris-Saclay, Orsay, France
| | - Olivier Bourron
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Paris, France
- Institut Hospitalo-Universitaire ICAN, Paris, France
- Assistance Publique-Hôpitaux de Paris, Département de Diabétologie et Maladies Métaboliques, Hôpital Pitié-Salpêtrière, Paris, France
| | - Hervé Le Stunff
- Université Saclay, CNRS UMR 9197, Institut des Neurosciences Paris-Saclay, Orsay, France
| | - Eric Hajduch
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Paris, France
- Institut Hospitalo-Universitaire ICAN, Paris, France
- *Correspondence: Eric Hajduch
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Nieuwoudt S, Mulya A, Fealy CE, Martelli E, Dasarathy S, Naga Prasad SV, Kirwan JP. In vitro contraction protects against palmitate-induced insulin resistance in C2C12 myotubes. Am J Physiol Cell Physiol 2017; 313:C575-C583. [PMID: 28835436 DOI: 10.1152/ajpcell.00123.2017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 08/16/2017] [Accepted: 08/21/2017] [Indexed: 12/13/2022]
Abstract
We are interested in understanding mechanisms that govern the protective role of exercise against lipid-induced insulin resistance, a key driver of type 2 diabetes. In this context, cell culture models provide a level of abstraction that aid in our understanding of cellular physiology. Here we describe the development of an in vitro myotube contraction system that provides this protective effect, and which we have harnessed to investigate lipid-induced insulin resistance. C2C12 myocytes were differentiated into contractile myotubes. A custom manufactured platinum electrode system and pulse stimulator, with polarity switching, provided an electrical pulse stimulus (EPS) (1 Hz, 6-ms pulse width, 1.5 V/mm, 16 h). Contractility was assessed by optical flow flied spot noise mapping and inhibited by application of ammonium acetate. Following EPS, myotubes were challenged with 0.5 mM palmitate for 4 h. Cells were then treated with or without insulin for glucose uptake (30 min), secondary insulin signaling activation (10 min), and phosphoinositide 3-kinase-α (PI3Kα) activity (5 min). Prolonged EPS increased non-insulin-stimulated glucose uptake (83%, P = 0.002), Akt (Thr308) phosphorylation (P = 0.005), and insulin receptor substrate-1 (IRS-1)-associated PI3Kα activity (P = 0.048). Palmitate reduced insulin-specific action on glucose uptake (-49%, P < 0.001) and inhibited insulin-stimulated Akt phosphorylation (P = 0.049) and whole cell PI3Kα activity (P = 0.009). The inhibitory effects of palmitate were completely absent with EPS pretreatment at the levels of glucose uptake, insulin responsiveness, Akt phosphorylation, and whole cell PI3Kα activity. This model suggests that muscle contraction alone is a sufficient stimulus to protect against lipid-induced insulin resistance as evidenced by changes in the proximal canonical insulin-signaling pathway.
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Affiliation(s)
- Stephan Nieuwoudt
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio.,Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; and
| | - Anny Mulya
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; and
| | - Ciarán E Fealy
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; and
| | - Elizabeth Martelli
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Srinivasan Dasarathy
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; and
| | | | - John P Kirwan
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio; .,Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; and
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Lefai E, Blanc S, Momken I, Antoun E, Chery I, Zahariev A, Gabert L, Bergouignan A, Simon C. Exercise training improves fat metabolism independent of total energy expenditure in sedentary overweight men, but does not restore lean metabolic phenotype. Int J Obes (Lond) 2017; 41:1728-1736. [PMID: 28669989 DOI: 10.1038/ijo.2017.151] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 05/28/2017] [Accepted: 06/07/2017] [Indexed: 12/29/2022]
Abstract
BACKGROUND Obesity is a dietary fat storage disease. Although exercise prevents weight gain, effects of chronic training on dietary fat oxidation remains understudied in overweight adults. OBJECTIVE We tested whether 2 months of training at current guidelines increase dietary fat oxidation in sedentary overweight adults like in sedentary lean adults. DESIGN Sedentary lean (n=10) and overweight (n=9) men trained on a cycle ergometer at 50% VO2peak, 1 h day-1, four times per week, for 2 months while energy balance was clamped. Metabolic fate of [d31]palmitate and [1-13C]oleate mixed in standard meals, total substrate use, total energy expenditure (TEE), activity energy expenditure (AEE) and key muscle proteins/enzymes were measured before and at the end of the intervention. RESULTS Conversely to lean subjects, TEE and AEE did not increase in overweight participants due to a spontaneous decrease in non-training AEE. Despite this compensatory behavior, aerobic fitness, insulin sensitivity and fat oxidation were improved by exercise training. The latter was not explained by changes in dietary fat trafficking but more likely by a coordinated response at the muscle level enhancing fat uptake, acylation and oxidation (FABPpm, CD36, FATP1, ACSL1, CPT1, mtGPAT). ACSL1 fold change positively correlated with total fasting (R2=0.59, P<0.0001) and post-prandial (R2=0.49, P=0.0006) fat oxidation whereas mtGPAT fold change negatively correlated with dietary palmitate oxidation (R2=0.40, P=0.009), suggesting modified fat trafficking between oxidation and storage within the muscle. However, for most of the measured parameters the post-training values observed in overweight adults remained lower than the pre-training values observed in the lean subjects. CONCLUSION Independent of energy balance and TEE, exercise training at current recommendations improved fitness and fat oxidation in overweight adults. However the improved metabolic phenotype of overweight adults was not as healthy as the one of their lean counterparts before the 2-month training, likely due to the spontaneous reduction in non-training AEE.
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Affiliation(s)
- E Lefai
- CARMEN, INSERM U1060/University of Lyon 1/INRA U1235, Lyon, France
| | - S Blanc
- Institut Pluridisciplinaire Hubert Curien, Université de Strasbourg, CNRS UMR 7178, Strasbourg, France
| | - I Momken
- Université d'Evry Val d'Essonne, Unité de Biologie Intégrative des Adaptations à l'Exercice, Evry, France
| | - E Antoun
- Institut Pluridisciplinaire Hubert Curien, Université de Strasbourg, CNRS UMR 7178, Strasbourg, France
| | - I Chery
- Institut Pluridisciplinaire Hubert Curien, Université de Strasbourg, CNRS UMR 7178, Strasbourg, France
| | - A Zahariev
- Institut Pluridisciplinaire Hubert Curien, Université de Strasbourg, CNRS UMR 7178, Strasbourg, France
| | - L Gabert
- CARMEN, INSERM U1060/University of Lyon 1/INRA U1235, Lyon, France.,Human Nutrition Research Centre of Rhône-Alpes, Hospices Civils de Lyon, Lyon, France
| | - A Bergouignan
- Institut Pluridisciplinaire Hubert Curien, Université de Strasbourg, CNRS UMR 7178, Strasbourg, France.,Anschutz Health and Wellness Center, Anschutz Medical Campus, Aurora, CO, USA.,Division of Endocrinology, Metabolism and Diabetes, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - C Simon
- CARMEN, INSERM U1060/University of Lyon 1/INRA U1235, Lyon, France.,Human Nutrition Research Centre of Rhône-Alpes, Hospices Civils de Lyon, Lyon, France
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Boulinguiez A, Staels B, Duez H, Lancel S. Mitochondria and endoplasmic reticulum: Targets for a better insulin sensitivity in skeletal muscle? Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:901-916. [PMID: 28529179 DOI: 10.1016/j.bbalip.2017.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 05/15/2017] [Accepted: 05/17/2017] [Indexed: 12/16/2022]
Abstract
Obesity and its associated metabolic disorders represent a major health burden, with economic and social consequences. Although adapted lifestyle and bariatric surgery are effective in reducing body weight, obesity prevalence is still rising. Obese individuals often become insulin-resistant. Obesity impacts on insulin responsive organs, such as the liver, adipose tissue and skeletal muscle, and increases the risk of cardiovascular diseases, type 2 diabetes and cancer. In this review, we discuss the effects of obesity and insulin resistance on skeletal muscle, an important organ for the control of postprandial glucose. The roles of mitochondria and the endoplasmic reticulum in insulin signaling are highlighted and potential innovative research and treatment perspectives are proposed.
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Affiliation(s)
- Alexis Boulinguiez
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011 - EGID, F-59000, Lille, France.
| | - Bart Staels
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011 - EGID, F-59000, Lille, France.
| | - Hélène Duez
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011 - EGID, F-59000, Lille, France.
| | - Steve Lancel
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011 - EGID, F-59000, Lille, France.
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Dotzert MS, Murray MR, McDonald MW, Olver TD, Velenosi TJ, Hennop A, Noble EG, Urquhart BL, Melling CWJ. Metabolomic Response of Skeletal Muscle to Aerobic Exercise Training in Insulin Resistant Type 1 Diabetic Rats. Sci Rep 2016; 6:26379. [PMID: 27197730 PMCID: PMC4873835 DOI: 10.1038/srep26379] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/28/2016] [Indexed: 12/21/2022] Open
Abstract
The etiology of insulin resistance in Type 1 Diabetes (T1D) is unknown, however it affects approximately 20% of T1D patients. Intramyocellular lipids (IMCL) have been identified as a mechanism of insulin resistance. We examined skeletal muscle of T1D rats to determine if alterations in lipid metabolism were evident and whether aerobic exercise training improves IMCL and insulin resistance. To do so, 48 male Sprague-Dawley rats were divided into control (C), sedentary diabetes (D) and diabetes exercise (DX) groups. Following multiple low-dose Streptozotocin (STZ) injections (20 mg/kg), glycemia (9-15 mM) was maintained using insulin treatment. DX were treadmill trained at high intensity (~75% V02max; 5days/week) for 10 weeks. The results demonstrate that D exhibited insulin resistance compared with C and DX, indicated by decreased glucose infusion rate during a hyperinsulinemic-euglycemic clamp (p < 0.05). There were no differences between C and DX, suggesting that exercise improved insulin resistance (p < 0.05). Metabolomics analysis revealed a significant shift in lipid metabolism whereby notable fatty acid metabolites (arachidonic acid, palmitic acid and several polyunsaturated fatty acids) were significantly elevated in D compared to C and DX. Based on the intermediates observed, insulin resistance in T1D is characterized by an insulin-desensitizing intramyocellular fatty acid metabolite profile that is ameliorated with exercise training.
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Affiliation(s)
- Michelle S. Dotzert
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| | - Michael R. Murray
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| | - Matthew W. McDonald
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| | - T. Dylan Olver
- Neurovascular Research Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| | - Thomas J. Velenosi
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Anzel Hennop
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Earl G. Noble
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| | - Brad L. Urquhart
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- Lawson Health Research Institute, London, Ontario, Canada
- Department of Medicine, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - C. W. James Melling
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
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Bergman BC, Brozinick JT, Strauss A, Bacon S, Kerege A, Bui HH, Sanders P, Siddall P, Wei T, Thomas MK, Kuo MS, Perreault L. Muscle sphingolipids during rest and exercise: a C18:0 signature for insulin resistance in humans. Diabetologia 2016; 59:785-98. [PMID: 26739815 DOI: 10.1007/s00125-015-3850-y] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 12/03/2015] [Indexed: 12/18/2022]
Abstract
AIMS/HYPOTHESES Ceramides and other sphingolipids comprise a family of lipid molecules that accumulate in skeletal muscle and promote insulin resistance. Chronic endurance exercise training decreases muscle ceramides and other sphingolipids, but less is known about the effects of a single bout of exercise. METHODS We measured basal relationships and the effect of acute exercise (1.5 h at 50% [Formula: see text]) and recovery on muscle sphingolipid content in obese volunteers, endurance trained athletes and individuals with type 2 diabetes. RESULTS Muscle C18:0 ceramide (p = 0.029), dihydroceramide (p = 0.06) and glucosylceramide (p = 0.03) species were inversely related to insulin sensitivity without differences in total ceramide, dihydroceramide, and glucosylceramide concentration. Muscle C18:0 dihydroceramide correlated with markers of muscle inflammation (p = 0.04). Transcription of genes encoding sphingolipid synthesis enzymes was higher in athletes, suggesting an increased capacity for sphingolipid synthesis. The total concentration of muscle ceramides and sphingolipids increased during exercise and then decreased after recovery, during which time ceramide levels reduced to significantly below basal levels. CONCLUSIONS/INTERPRETATION These data suggest ceramide and other sphingolipids containing stearate (18:0) are uniquely related to insulin resistance in skeletal muscle. Recovery from an exercise bout decreased muscle ceramide concentration; this may represent a mechanism promoting the insulin-sensitising effects of acute exercise.
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Affiliation(s)
- Bryan C Bergman
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, PO Box 6511, MS 8106, Aurora, CO, 80045, USA.
| | | | - Allison Strauss
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, PO Box 6511, MS 8106, Aurora, CO, 80045, USA
| | - Samantha Bacon
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, PO Box 6511, MS 8106, Aurora, CO, 80045, USA
| | - Anna Kerege
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, PO Box 6511, MS 8106, Aurora, CO, 80045, USA
| | | | | | | | - Tao Wei
- Eli Lilly and Company, Indianapolis, IN, USA
| | | | | | - Leigh Perreault
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, PO Box 6511, MS 8106, Aurora, CO, 80045, USA
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Li Y, Xu S, Zhang X, Yi Z, Cichello S. Skeletal intramyocellular lipid metabolism and insulin resistance. BIOPHYSICS REPORTS 2015; 1:90-98. [PMID: 26942223 PMCID: PMC4762133 DOI: 10.1007/s41048-015-0013-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 04/10/2015] [Indexed: 12/24/2022] Open
Abstract
Lipids stored in skeletal muscle cells are known as intramyocellular lipid (IMCL). Disorders involving IMCL and its causative factor, circulatory free fatty acids (FFAs), induce a toxic state and ultimately result in insulin resistance (IR) in muscle tissue. On the other hand, intramuscular triglyceride (IMTG), the most abundant component of IMCL and an essential energy source for active skeletal muscle, is different from other IMCLs, as it is stored in lipid droplets and plays a pivotal role in skeletal muscle energy homeostasis. This review discusses the association of FFA-induced ectopic lipid accumulation and IR, with specific emphasis on the relationship between IMCL/IMTG metabolism and IR.
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Affiliation(s)
- Yiran Li
- Department of Biological Science and Biotechnology, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191 China ; National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
| | - Shimeng Xu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China ; University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Xuelin Zhang
- Capital University of Physical Education and Sport, Beijing, 100191 China
| | - Zongchun Yi
- Department of Biological Science and Biotechnology, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191 China
| | - Simon Cichello
- School of Life Sciences, La Trobe University, Melbourne, VIC 3086 Australia
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Abstract
Obesity is a major predisposing factor for the development of type 2 diabetes (T2D) and is an escalating public health issue around the world. The transition from obesity to T2D is preceded by the induction of a state of insulin resistance, which occurs in response to genetic factors and environmental influences, such as diet. Recent advances have implicated inflammatory immune cells and cytokines as critical pathogenic mediators of insulin resistance and T2D. In particular proinflammatory T helper (Th)1 cells and M1 macrophages are recruited to adipose tissue in response to high fat diet and directly promote the development of insulin resistance. The function of these two cell types is linked by the actions of the cytokine interferon (IFN)γ and one of its major transcriptional regulators T-bet. Recent studies in animal models of T2D demonstrate that T-bet is critical for the development of insulin resistance in response to high fat diet as T-bet-deficient animals are protected from the development of insulin resistance. These data indicate that T-bet and type 1 immunity may constitute novel sites of therapeutic intervention for the treatment of insulin resistance and T2D, in obese human patients.
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Affiliation(s)
- Jibran A Wali
- Immunology and Diabetes Unit, St Vincent’s Institute, University of Melbourne, Fitzroy, Victoria, Australia
- Department of Medicine, St Vincent’s Hospital, University of Melbourne, Fitzroy, Victoria, Australia
| | - Helen E Thomas
- Immunology and Diabetes Unit, St Vincent’s Institute, University of Melbourne, Fitzroy, Victoria, Australia
- Department of Medicine, St Vincent’s Hospital, University of Melbourne, Fitzroy, Victoria, Australia
| | - Andrew PR Sutherland
- Immunology and Diabetes Unit, St Vincent’s Institute, University of Melbourne, Fitzroy, Victoria, Australia
- Correspondence: Andrew PR Sutherland, Immunology and Diabetes Unit, St Vincent’s Institute, 9 Princes St, Fitzroy, Victoria, 3065 Australia, Tel +61 3 9288 2480, Fax +61 3 9416 2676, Email
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Tishinsky JM, De Boer AA, Dyck DJ, Robinson LE. Modulation of visceral fat adipokine secretion by dietary fatty acids and ensuing changes in skeletal muscle inflammation. Appl Physiol Nutr Metab 2013; 39:28-37. [PMID: 24383504 DOI: 10.1139/apnm-2013-0135] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Given the link between obesity and insulin resistance, the role of adipose-derived factors in communicating with skeletal muscle to affect its function is important. We sought to determine if high fat diets modulate visceral adipose tissue (VAT) adipokines with subsequent effects on skeletal muscle inflammation and insulin sensitivity. Rats were fed (i) low fat (LF), (ii) high saturated fatty acid (SFA), or (iii) high SFA with n-3 polyunsaturated fatty acid (SFA/n-3 PUFA) diets for 4 weeks. VAT-derived adipokines were measured in adipose conditioned medium (ACM) after 72 h. Next, skeletal muscles from LF-fed rats were incubated for 8 h in (i) control buffer (CON), (ii) CON with 2 mmol·L(-1) palmitate (PALM, positive control), (iii) ACM from LF, (iv) ACM from SFA, or (v) ACM from SFA/n-3 PUFA. ACM from rats fed SFA and SFA/n-3 PUFA had increased (P ≤ 0.05) interleukin-6 (IL-6) (+31%) and monocyte chemoattractant protein-1 (MCP-1) (+30%). Adiponectin was decreased (-29%, P ≤ 0.05) in ACM from SFA, and this was prevented in SFA/n-3 PUFA ACM. Toll-like receptor 4 (TLR4) gene expression was increased (P ≤ 0.05) in PALM soleus muscle (+356%) and all ACM groups (+175%-191%). MCP-1 gene expression was elevated (P ≤ 0.05) in PALM soleus muscle (+163%) and soleus muscle incubated in ACM from animals fed SFA (+159%) and SFA/n-3 PUFA (+151%). Glucose transport was impaired (P ≤ 0.05) in PALM muscles but preserved in ACM groups. Acute exposure of muscle to fatty acid modulated adipokines affects skeletal muscle inflammatory gene expression but not insulin sensitivity.
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Affiliation(s)
- Justine M Tishinsky
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
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Gulli RA, Tishinsky JM, MacDonald T, Robinson LE, Wright DC, Dyck DJ. Exercise restores insulin, but not adiponectin, response in skeletal muscle of high-fat fed rodents. Am J Physiol Regul Integr Comp Physiol 2012; 303:R1062-70. [DOI: 10.1152/ajpregu.00176.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
High-fat (HF) diets impair skeletal muscle response to the insulin-sensitizing adipokine adiponectin (Ad) in rodents, preceding the development of insulin resistance. Skeletal muscle insulin response in HF-fed rats can be restored with chronic exercise; whether recovery of skeletal muscle Ad response is necessary for the exercise-induced recovery of insulin-stimulated glucose transport is not known. In the current study, insulin and Ad resistance were induced in rodents with 4 wk of HF feeding (HF4; low-fat fed animals used as control). Rats were then treadmill-exercised (HF5EX1, HF6EX2) or supplemented orally with the pharmacological agent β-guadinoproprionic acid (GPA; HF5GPA1, HF6GPA2) for 1 or 2 wk with continued HF feeding. Insulin and Ad responses (glucose transport and palmitate oxidation, respectively) were assessed 48 h after the last exercise bout ex vivo in isolated solei. Insulin response was impaired following 4 wk of HF feeding and improved with 1 and 2 wk of exercise and β-GPA supplementation (HF5EX1, HF6EX2, HF5GPA1, and HF6GPA2). The recovery of insulin response generally coincided with improved Akt Thr308 phosphorylation in HF5GPA1, HF6EX2, and HF6GPA2, although not in HF5EX1. Ad-stimulated palmitate oxidation was not restored with either treatment. Total protein contents of AdipoR1, AdipoR2, APPL1, and APPL2, as well as total and phosphorylated AMPK and ACC were unaltered by diet, exercise, and β-GPA at the assessed time points. We conclude that the exercise and pharmacologically (β-GPA)-induced recovery of skeletal muscle insulin response after HF feeding is not dependent on the restoration of Ad response, as assessed ex vivo.
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Affiliation(s)
- Roberto A. Gulli
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Justine M. Tishinsky
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Tara MacDonald
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Lindsay E. Robinson
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - David C. Wright
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - David J. Dyck
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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Coen PM, Goodpaster BH. Role of intramyocelluar lipids in human health. Trends Endocrinol Metab 2012; 23:391-8. [PMID: 22721584 PMCID: PMC4908975 DOI: 10.1016/j.tem.2012.05.009] [Citation(s) in RCA: 176] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 05/21/2012] [Accepted: 05/22/2012] [Indexed: 11/20/2022]
Abstract
Intramyocellular lipid (IMCL) is predominantly stored as intramuscular triglyceride (IMTG) in lipid droplets and is utilized as metabolic fuel during physical exercise. IMTG is also implicated in muscle insulin resistance (IR) in type 2 diabetes. However, it has become apparent that lipid moieties such as ceramide and diacylglycerol are the likely culprits of IR. This article reviews current knowledge of IMCL-mediated IR and important areas of investigation, including myocellular lipid transport and lipid droplet proteins. Several crucial questions remain unanswered, such as the identity of specific ceramide and diacylglycerol species that mediate IR in human muscle and their subcellular location. Quantitative lipidomics and proteomics of targeted subcellular organelles will help to better define the mechanisms underlying pathological IMCL accumulation and IR.
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Affiliation(s)
- Paul M Coen
- Department of Health and Physical Activity, University of Pittsburgh, Trees Hall Rm 134D, Allequippa Street and Darragh Street, Pittsburgh, PA 15260, USA
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Watt MJ, Hoy AJ. Lipid metabolism in skeletal muscle: generation of adaptive and maladaptive intracellular signals for cellular function. Am J Physiol Endocrinol Metab 2012; 302:E1315-28. [PMID: 22185843 DOI: 10.1152/ajpendo.00561.2011] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Fatty acids derived from adipose tissue lipolysis, intramyocellular triacylglycerol lipolysis, or de novo lipogenesis serve a variety of functions in skeletal muscle. The two major fates of fatty acids are mitochondrial oxidation to provide energy for the myocyte and storage within a variety of lipids, where they are stored primarily in discrete lipid droplets or serve as important structural components of membranes. In this review, we provide a brief overview of skeletal muscle fatty acid metabolism and highlight recent notable advances in the field. We then 1) discuss how lipids are stored in and mobilized from various subcellular locations to provide adaptive or maladaptive signals in the myocyte and 2) outline how lipid metabolites or metabolic byproducts derived from the actions of triacylglycerol metabolism or β-oxidation act as positive and negative regulators of insulin action. We have placed an emphasis on recent developments in the lipid biology field with respect to understanding skeletal muscle physiology and discuss unanswered questions and technical limitations for assessing lipid signaling in skeletal muscle.
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Affiliation(s)
- Matthew J Watt
- Biology of Lipid Metabolism Laboratory, Department of Physiology, Monash University, Clayton, Victoria 3800, Australia.
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Abstract
The recent implementation of genomic and lipidomic approaches has produced a large body of evidence implicating the sphingolipid ceramide in a diverse range of physiological processes and as a critical modulator of cellular stress. In this review, we discuss from a historical perspective the most important discoveries produced over the last decade supporting a role for ceramide and its metabolites in the pathogenesis of insulin resistance and other obesity-associated metabolic diseases. Moreover, we describe how a ceramide-centric view of insulin resistance might be reconciled in the context of other prominent models of nutrient-induced insulin resistance.
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Affiliation(s)
- Jose A Chavez
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, NC 27704, USA.
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