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Gupta S, Bharatha A, Cohall D, Rahman S, Haque M, Azim Majumder MA. Aerobic Exercise and Endocannabinoids: A Narrative Review of Stress Regulation and Brain Reward Systems. Cureus 2024; 16:e55468. [PMID: 38440201 PMCID: PMC10910469 DOI: 10.7759/cureus.55468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2024] [Indexed: 03/06/2024] Open
Abstract
Aerobic exercise is a widely adopted practice, not solely for enhancing fitness and reducing the risk of various diseases but also for its ability to uplift mood and aid in addressing depression and anxiety disorders. Within the scope of this narrative review, we seek to consolidate current insights into the endocannabinoid-mediated regulation of stress and the brain's reward mechanism resulting from engaging in aerobic exercise. A comprehensive search was conducted across Medline, SPORTDiscus, Pubmed, and Scopus, encompassing data available until November 30, 2023. This review indicates that a bout of aerobic exercise, particularly of moderate intensity, markedly augments circulating levels of endocannabinoids - N-arachidonoyl-ethanolamine (AEA) and 2-acylglycerol (2-AG), that significantly contributes to mood elevation and reducing stress in healthy individuals. The current understanding of how aerobic exercise impacts mental health and mood improvement is still unclear. Moderate and high-intensity aerobic exercise modulates stress through a negative feedback mechanism targeting both the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic nervous system, thereby facilitating stress regulation crucial role in endocannabinoid synthesis, ultimately culminating in the orchestration of negative feedback across multiple tiers of the HPA axis, coupled with its influence over cortical and subcortical brain structures. The endocannabinoid has been observed to govern the release of neurotransmitters from diverse neuronal populations, implying a universal mechanism that fine-tunes neuronal activity and consequently modulates both emotional and stress-related responses. Endocannabinoids further assume a pivotal function within brain reward mechanisms, primarily mediated by CB1 receptors distributed across diverse cerebral centers. Notably, these endocannabinoids partake in natural reward processes, as exemplified in aerobic exercise, by synergizing with the dopaminergic reward system. The genesis of this reward pathway can be traced to the ventral tegmental area, with dopamine neurons predominantly projecting to the nucleus accumbens, thereby inciting dopamine release in response to rewarding stimuli.
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Affiliation(s)
- Subir Gupta
- Physiology, Faculty of Medical Sciences, The University of the West Indies, Cave Hill Campus, Bridgetown, BRB
| | - Ambadasu Bharatha
- Pharmacology, Faculty of Medical Sciences, The University of the West Indies, Cave Hill Campus, Bridgetown, BRB
| | - Damian Cohall
- Pharmacology, Faculty of Medical Sciences, The University of the West Indies, Cave Hill Campus, Bridgetown, BRB
| | - Sayeeda Rahman
- Pharmacology, School of Medicine, American University of Integrative Sciences, Bridgetown, BRB
| | - Mainul Haque
- Pharmacology and Therapeutics, Karnavati Scientific Research Center (KSRC) School of Dentistry, Karnavati University, Gandhinagar, IND
- Pharmacology and Therapeutics, National Defence University of Malaysia, Kuala Lumpur, MYS
| | - Md Anwarul Azim Majumder
- Medical Education, Faculty of Medical Sciences, The University of the West Indies, Cave Hill Campus, Bridgetown, BRB
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Watkins BA, Newman JW, Kuchel GA, Fiehn O, Kim J. Dietary Docosahexaenoic Acid and Glucose Systemic Metabolic Changes in the Mouse. Nutrients 2023; 15:2679. [PMID: 37375583 DOI: 10.3390/nu15122679] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 05/31/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
The endocannabinoid system (ECS) participates in regulating whole body energy balance. Overactivation of the ECS has been associated with the negative consequence of obesity and type 2 diabetes. Since activators of the ECS rely on lipid-derived ligands, an investigation was conducted to determine whether dietary PUFA could influence the ECS to affect glucose clearance by measuring metabolites of macronutrient metabolism. C57/blk6 mice were fed a control or DHA-enriched semi-purified diet for a period of 112 d. Plasma, skeletal muscle, and liver were collected after 56 d and 112 d of feeding the diets for metabolomics analysis. Key findings characterized a shift in glucose metabolism and greater catabolism of fatty acids in mice fed the DHA diet. Glucose use and promotion of fatty acids as substrate were found based on levels of metabolic pathway intermediates and altered metabolic changes related to pathway flux with DHA feeding. Greater levels of DHA-derived glycerol lipids were found subsequently leading to the decrease of arachidonate-derived endocannabinoids (eCB). Levels of 1- and 2-arachidonylglcerol eCB in muscle and liver were lower in the DHA diet group compared to controls. These findings demonstrate that DHA feeding in mice alters macronutrient metabolism and may restore ECS tone by lowering arachidonic acid derived eCB.
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Affiliation(s)
- Bruce A Watkins
- Department of Nutrition, University of California, Davis, Davis, CA 95616, USA
- Center on Aging, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - John W Newman
- United States Department of Agriculture, Agricultural Research Service, Western Human Nutrition Research Center, Davis, CA 95616, USA
| | - George A Kuchel
- Center on Aging, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Oliver Fiehn
- NIH UC Davis West Coast Metabolomics Center, Davis, CA 95616, USA
| | - Jeffrey Kim
- Genome and Biomedical Sciences Facility, University of California, Davis, Davis, CA 95616, USA
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Belitardo de Oliveira A, de Mello MT, Tufik S, Peres MFP. Weight loss and improved mood after aerobic exercise training are linked to lower plasma anandamide in healthy people. Physiol Behav 2018; 201:191-197. [PMID: 30578894 DOI: 10.1016/j.physbeh.2018.12.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 12/12/2018] [Accepted: 12/14/2018] [Indexed: 12/20/2022]
Abstract
Anandamide, a major endocannabinoid, participates in energy metabolism homeostasis and neurobehavioral processes. In a secondary analysis of an open-label, randomized controlled trial, we investigated the long-term effect of aerobic exercise on resting plasma anandamide, and explored its relationship with changes in body weight, cardiorespiratory fitness, and mood status in healthy, physically inactive individuals. Participants recruited between March 2013 to August 2015 at the UNIFESP's Neurology/Psychobiology Department were randomly allocated into a 12-weeks supervised moderate exercise program, or into waitlist, control condition. Thirty-four participants (age = 38 ± 11.5, BMI = 26.6 ± 3.6) were intention to treat-analysed (Exercise: n = 17; Control: n = 17). After intervention, there were significant decreases in plasma anandamide (p < .01), anger, anxiety, and body weight (all p < .05), whereas cardiorespiratory fitness increased (p < .05) in the exercise group. There were no significant changes in any variable for the control group. In the whole cohort, adjusted R2 of multiple linear regressions showed that 12.2% of change body weight was explained by changes in anandamide (β = 0.391, p = .033), while 27% of change in mood disturbance (β = 0.546, p = .003), and 13.1% of change in anger (β = 0.404, p = .03) was explained by changes in anandamide. Our data suggest that the weight loss and mood improvement through regular moderate exercise may involve changes in anandamide metabolism/signaling. Trials registration: #NCT01972607.
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Affiliation(s)
- Arão Belitardo de Oliveira
- Universidade Federal de São Paulo, Departament of Neurology and Neurosurgery, 669, Pedro de Toledo, CEP 04039-032 São Paulo, Brazil.
| | - Marco Tulio de Mello
- Universidade Federal de Minas Gerais, Departament of Sports Science, 6627, Pres. Antônio Carlos Av, CEP 31270-901 Belo Horizonte, Brazil
| | - Serio Tufik
- Universidade Federal de São Paulo, Departament of Psychobiology, 862, Botucatu, CEP 04032-030 São Paulo, SP, Brazil
| | - Mario Fernando Prieto Peres
- Albert Einstein Israeli Hospital, Brain Institute, 627/701, Avenida Albert Einstein, CEP 05652-900 São Paulo, Brazil; Universidade de São Paulo, Medical School, Psychiatry Institute, 785, Rua Dr. Ovídio Pires de Campos: CEP 05403-903 São Paulo, SP, Brazil
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Lai N, Kummitha C, Hoppel C. Defects in skeletal muscle subsarcolemmal mitochondria in a non-obese model of type 2 diabetes mellitus. PLoS One 2017; 12:e0183978. [PMID: 28850625 PMCID: PMC5574550 DOI: 10.1371/journal.pone.0183978] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 08/15/2017] [Indexed: 11/18/2022] Open
Abstract
Skeletal muscle resistance to insulin is related to accumulation of lipid-derived products, but it is not clear whether this accumulation is caused by skeletal muscle mitochondrial dysfunction. Diabetes and obesity are reported to have a selective effect on the function of subsarcolemmal and interfibrillar mitochondria in insulin-resistant skeletal muscle. The current study investigated the role of the subpopulations of mitochondria in the pathogenesis of insulin resistance in the absence of obesity. A non-obese spontaneous rat model of type 2 diabetes mellitus, (Goto-Kakizaki), was used to evaluate function and biochemical properties in both populations of skeletal muscle mitochondria. In subsarcolemmal mitochondria, minor defects are observed whereas in interfibrillar mitochondria function is preserved. Subsarcolemmal mitochondria defects characterized by a mild decline of oxidative phosphorylation efficiency are related to ATP synthase and structural alterations of inner mitochondria membrane but are considered unimportant because of the absence of defects upstream as shown with polarographic and spectrophometric assays. Fatty acid transport and oxidation is preserved in both population of mitochondria, whereas palmitoyl-CoA increased 25% in interfibrillar mitochondria of diabetic rats. Contrary to popular belief, these data provide compelling evidence that mitochondrial function is unaffected in insulin-resistant skeletal muscle from T2DM non-obese rats.
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Affiliation(s)
- Nicola Lai
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia, United States of America
- Biomedical Engineering Institute, Old Dominion University, Norfolk, Virginia, United States of America
- Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
| | - China Kummitha
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia, United States of America
- Biomedical Engineering Institute, Old Dominion University, Norfolk, Virginia, United States of America
- Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Charles Hoppel
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Center for Mitochondrial Disease, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
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Abstract
Non-alcoholic fatty liver disease (NAFLD) is the most common form of liver disease and leading cause of cirrhosis in the United States and developed countries. NAFLD is closely associated with obesity, insulin resistance and metabolic syndrome, significantly contributing to the exacerbation of the latter. Although NAFLD represents the hepatic component of metabolic syndrome, it can also be found in patients prior to their presentation with other manifestations of the syndrome. The pathogenesis of NAFLD is complex and closely intertwined with insulin resistance and obesity. Several mechanisms are undoubtedly involved in its pathogenesis and progression. In this review, we bring together the current understanding of the pathogenesis that makes NAFLD a systemic disease.
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Affiliation(s)
- Isabella Reccia
- Department of Surgery and Cancer Faculty of Medicine, Hammersmith Hospital, Imperial College London, UK.
| | - Jayant Kumar
- Department of Surgery and Cancer Faculty of Medicine, Hammersmith Hospital, Imperial College London, UK.
| | - Cherif Akladios
- Department of Surgery and Cancer Faculty of Medicine, Hammersmith Hospital, Imperial College London, UK.
| | - Francesco Virdis
- Department of Surgery and Cancer Faculty of Medicine, Hammersmith Hospital, Imperial College London, UK.
| | - Madhava Pai
- Department of Surgery and Cancer Faculty of Medicine, Hammersmith Hospital, Imperial College London, UK.
| | - Nagy Habib
- Department of Surgery and Cancer Faculty of Medicine, Hammersmith Hospital, Imperial College London, UK.
| | - Duncan Spalding
- Department of Surgery and Cancer Faculty of Medicine, Hammersmith Hospital, Imperial College London, UK.
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Oláh T, Bodnár D, Tóth A, Vincze J, Fodor J, Reischl B, Kovács A, Ruzsnavszky O, Dienes B, Szentesi P, Friedrich O, Csernoch L. Cannabinoid signalling inhibits sarcoplasmic Ca 2+ release and regulates excitation-contraction coupling in mammalian skeletal muscle. J Physiol 2016; 594:7381-7398. [PMID: 27641745 DOI: 10.1113/jp272449] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 09/14/2016] [Indexed: 01/09/2023] Open
Abstract
KEY POINTS Marijuana was found to cause muscle weakness, although the exact regulatory role of its receptors (CB1 cannabinoid receptor; CB1R) in the excitation-contraction coupling (ECC) of mammalian skeletal muscle remains unknown. We found that CB1R activation or its knockout did not affect muscle force directly, whereas its activation decreased the Ca2+ -sensitivity of the contractile apparatus and made the muscle fibres more prone to fatigue. We demonstrate that CB1Rs are not connected to the inositol 1,4,5-trisphosphate pathway either in myotubes or in adult muscle fibres. By contrast, CB1Rs constitutively inhibit sarcoplasmic Ca2+ release and sarcoplasmic reticulum Ca2+ ATPase during ECC in a Gi/o protein-mediated way in adult skeletal muscle fibres but not in myotubes. These results help with our understanding of the physiological effects and pathological consequences of CB1R activation in skeletal muscle and may be useful in the development of new cannabinoid drugs. ABSTRACT Marijuana was found to cause muscle weakness, although it is unknown whether it affects the muscles directly or modulates only the motor control of the central nervous system. Although the presence of CB1 cannabinoid receptors (CB1R), which are responsible for the psychoactive effects of the drug in the brain, have recently been demonstrated in skeletal muscle, it is unclear how CB1R-mediated signalling affects the contraction and Ca²⁺ homeostasis of mammalian skeletal muscle. In the present study, we demonstrate that in vitro CB1R activation increased muscle fatigability and decreased the Ca2+ -sensitivity of the contractile apparatus, whereas it did not alter the amplitude of single twitch contractions. In myotubes, CB1R agonists neither evoked, nor influenced inositol 1,4,5-trisphosphate (IP3 )-mediated Ca2+ transients, nor did they alter excitation-contraction coupling. By contrast, in isolated muscle fibres of wild-type mice, although CB1R agonists did not evoke IP3 -mediated Ca2+ transients too, they significantly reduced the amplitude of the depolarization-evoked transients in a pertussis-toxin sensitive manner, indicating a Gi/o protein-dependent mechanism. Concurrently, on skeletal muscle fibres isolated from CB1R-knockout animals, depolarization-evoked Ca2+ transients, as well qas Ca2+ release flux via ryanodine receptors (RyRs), and the total amount of released Ca2+ was significantly greater than that from wild-type mice. Our results show that CB1R-mediated signalling exerts both a constitutive and an agonist-mediated inhibition on the Ca2+ transients via RyR, regulates the activity of the sarcoplasmic reticulum Ca2+ ATPase and enhances muscle fatigability, which might decrease exercise performance, thus playing a role in myopathies, and therefore should be considered during the development of new cannabinoid drugs.
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Affiliation(s)
- Tamás Oláh
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Dóra Bodnár
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Adrienn Tóth
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - János Vincze
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - János Fodor
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Barbara Reischl
- Institute of Medical Biotechnology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Adrienn Kovács
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Olga Ruzsnavszky
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Beatrix Dienes
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter Szentesi
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Oliver Friedrich
- Institute of Medical Biotechnology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - László Csernoch
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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Abstract
Heart failure is associated with generalized insulin resistance. Moreover, insulin-resistant states such as type 2 diabetes mellitus and obesity increases the risk of heart failure even after adjusting for traditional risk factors. Insulin resistance or type 2 diabetes mellitus alters the systemic and neurohumoral milieu, leading to changes in metabolism and signaling pathways in the heart that may contribute to myocardial dysfunction. In addition, changes in insulin signaling within cardiomyocytes develop in the failing heart. The changes range from activation of proximal insulin signaling pathways that may contribute to adverse left ventricular remodeling and mitochondrial dysfunction to repression of distal elements of insulin signaling pathways such as forkhead box O transcriptional signaling or glucose transport, which may also impair cardiac metabolism, structure, and function. This article will review the complexities of insulin signaling within the myocardium and ways in which these pathways are altered in heart failure or in conditions associated with generalized insulin resistance. The implications of these changes for therapeutic approaches to treating or preventing heart failure will be discussed.
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Affiliation(s)
- Christian Riehle
- From the Division of Endocrinology and Metabolism, Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City
| | - E Dale Abel
- From the Division of Endocrinology and Metabolism, Fraternal Order of Eagles Diabetes Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City.
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Palmitic acid and oleic acid differentially regulate choline transporter-like 1 levels and glycerolipid metabolism in skeletal muscle cells. Lipids 2014; 49:731-44. [PMID: 24972900 DOI: 10.1007/s11745-014-3925-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 06/16/2014] [Indexed: 12/20/2022]
Abstract
Choline is an essential nutrient required for the biosynthesis of membrane lipid phosphatidylcholine (PtdCho). Here we elucidate the mechanism of how palmitic acid (PAM) and oleic acid (OLA) regulate choline transporter-like protein 1 (CTL1/SLC44A1) function. We evaluated the mechanism of extracellular and intracellular transport of choline, and their contribution to PtdCho and other glycerolipid-diacylglycerol (DAG) and triacylglycerol (TAG) homeostasis in differentiated skeletal muscle cells. PAM reduces total and plasma membrane CTL1/SLC44A1 protein by lysosomal degradation, and limits the choline uptake while increasing DAG and TAG synthesis. OLA maintains total and plasma membrane CTL1/SLC44A1, but increases PtdCho synthesis more than PAM. OLA does not increase the rate of DAG synthesis, but does increase TAG content. Thus, the CTL1/SLC44A1 presence at the plasma membrane regulates choline requirements in accordance with the type of fatty acid. The increased PtdCho and TAG turnover by OLA stimulates cell growth and offers a specific protection mechanism from the excess of intracellular DAG and autophagy. This protection was present after OLA treatments, but not after PAM treatments. The mitochondrial choline uptake was reduced by both FA; however, the regulation is complex and guided not only by the presence of the mitochondrial CTL1/SLC44A1 protein but also by the membrane potential and general mitochondrial function.
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Leskinen T, Sipilä S, Kaprio J, Kainulainen H, Alen M, Kujala UM. Physically active vs. inactive lifestyle, muscle properties, and glucose homeostasis in middle-aged and older twins. AGE (DORDRECHT, NETHERLANDS) 2013; 35:1917-26. [PMID: 23124702 PMCID: PMC3776123 DOI: 10.1007/s11357-012-9486-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 10/23/2012] [Indexed: 06/01/2023]
Abstract
Exercise-induced positive changes in skeletal muscle properties and metabolism decrease the risk for disability, cardiometabolic diseases and mortality. Here, we studied muscle properties and glucose homeostasis in a non-exercise stage in twin pairs with co-twins discordant for physical activity habits for at least 32 years of their adult lives. Isometric knee extension force, MR imaging of midthigh tissue composition and muscle volume, and fasting blood samples were acquired from 16 same-sex (seven monozygotic, nine dizygotic) middle-aged and older twin pairs. The consistently active twins had 20 % higher knee extension forces than their inactive co-twins (p = 0.006) although the active twins had only 4 % higher midthigh muscle cross-sectional areas (p = 0.072). These results were similar in intrapair analysis in which only the seven identical twin pairs were included. The ratio between the area of midthigh fat and muscle tissues was significantly lower among the active twins (0.65 vs. 0.48, p = 0.006). The active twins had also lower fasting plasma glucose levels (5.1 vs 5.6 mmol/l, p = 0.041). The area of midthigh intramuscular (extramyocellular) fat was associated with the markers of glucose homeostasis, especially with glycated hemoglobin, and these associations were emphasized by the diabetic and inactive twins. Regular exercise throughout the adult life retains muscle strength and quality but not necessarily mass. The regular use of muscles also prevents from the accumulation of intramuscular fat which might be related to maintained glucose metabolism and, thus, prevention of metabolic disorders.
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Affiliation(s)
- T Leskinen
- Department of Health Sciences, University of Jyväskylä, PO Box 35 (VIV), FIN-40014, Jyväskylä, Finland,
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Serra D, Mera P, Malandrino MI, Mir JF, Herrero L. Mitochondrial fatty acid oxidation in obesity. Antioxid Redox Signal 2013; 19:269-84. [PMID: 22900819 PMCID: PMC3691913 DOI: 10.1089/ars.2012.4875] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
SIGNIFICANCE Current lifestyles with high-energy diets and little exercise are triggering an alarming growth in obesity. Excess of adiposity is leading to severe increases in associated pathologies, such as insulin resistance, type 2 diabetes, atherosclerosis, cancer, arthritis, asthma, and hypertension. This, together with the lack of efficient obesity drugs, is the driving force behind much research. RECENT ADVANCES Traditional anti-obesity strategies focused on reducing food intake and increasing physical activity. However, recent results suggest that enhancing cellular energy expenditure may be an attractive alternative therapy. CRITICAL ISSUES This review evaluates recent discoveries regarding mitochondrial fatty acid oxidation (FAO) and its potential as a therapy for obesity. We focus on the still controversial beneficial effects of increased FAO in liver and muscle, recent studies on how to potentiate adipose tissue energy expenditure, and the different hypotheses involving FAO and the reactive oxygen species production in the hypothalamic control of food intake. FUTURE DIRECTIONS The present review aims to provide an overview of novel anti-obesity strategies that target mitochondrial FAO and that will definitively be of high interest in the future research to fight against obesity-related disorders.
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Affiliation(s)
- Dolors Serra
- Department of Biochemistry and Molecular Biology, Facultat de Farmàcia, Universitat de Barcelona, Institut de Biomedicina de la Universitat de Barcelona IBUB, Barcelona, Spain
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Zhou Y, Rui L. Lipocalin 13 regulation of glucose and lipid metabolism in obesity. VITAMINS AND HORMONES 2013; 91:369-83. [PMID: 23374724 DOI: 10.1016/b978-0-12-407766-9.00015-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Lipocalin (LCN) family members are small secreted proteins that bind to small hydrophobic molecules via their characteristic central β-barrels. A couple of LCN family members, including major urinary protein 1, retinol-binding protein 4, LCN2, and LCN13, have been reported to regulate insulin sensitivity and nutrient metabolism. LCN13 is expressed by multiple tissues, including the liver, pancreas, epididymis, and skeletal muscle, and is secreted into the bloodstream in mice. Obesity is associated with a downregulation of LCN13 expression and lower levels of circulating LCN13. LCN13 therapies overcome LCN13 deficiency in mice with either genetic or dietary obesity, leading to an improvement in hyperglycemia, hyperinsulinemia, insulin resistance, glucose intolerance, and hepatic steatosis. In hepatocytes, LCN13 directly suppresses hepatic gluconeogenesis and lipogenesis but increases fatty acid β oxidation. LCN13 also enhances insulin sensitivity in adipocytes. The potential mechanisms of the antidiabetes and antisteatosis actions of LCN13 are discussed.
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Affiliation(s)
- Yingjiang Zhou
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Kou XH, Zhu MF, Chen D, Lu Y, Song HZ, Ye JL, Yue LF. Bilobetin ameliorates insulin resistance by PKA-mediated phosphorylation of PPARα in rats fed a high-fat diet. Br J Pharmacol 2012; 165:2692-706. [PMID: 22091731 DOI: 10.1111/j.1476-5381.2011.01727.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE The amelioration of insulin resistance by bilobetin is closely related to its hypolipidaemic effect. The aim of the present study was to determine the insulin-sensitizing mechanism of bilobetin by elucidating its effect on lipid metabolism. EXPERIMENTAL APPROACH Rats fed a high-fat diet were treated with bilobetin for either 4 or 14 days before applying a hyperinsulinaemic-euglycaemic clamp. Triglyceride and fatty acids labelled with radioactive isotopes were used to track the transportation and the fate of lipids in tissues. The activity of lipid metabolism-related enzymes and β-oxidation rate were measured. Western blot was used to investigate the phosphorylation, translocation and expression of PPARα in several tissues and cultured cells. The location of amino acid residues subjected to phosphorylation in PPARα was also studied. KEY RESULTS Bilobetin ameliorated insulin resistance, increased the hepatic uptake and oxidation of lipids, reduced very-low-density lipoprotein triglyceride secretion and blood triglyceride levels, enhanced the expression and activity of enzymes involved in β-oxidation and attenuated the accumulation of triglycerides and their metabolites in tissues. Bilobetin also increased the phosphorylation, nuclear translocation and activity of PPARα accompanied by elevated cAMP level and PKA activity. Threonine-129-alanine and/or serine-163-alanine mutations on the PPARα genes and PKA inhibitors prevented the effects of bilobetin on PPARα. However, cells overexpressing PKA appeared to stimulate the phosphorylation, nuclear translocation and activity of PPARα. CONCLUSIONS AND IMPLICATIONS Bilobetin treatment ameliorates hyperlipidaemia, lipotoxicity and insulin resistance in rats by stimulating PPARα-mediated lipid catabolism. PKA activation is crucial for this process.
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Affiliation(s)
- Xin-Hui Kou
- Department of Pharmacy, Wuxi People's Hospital affiliated to Nanjing Medical University, Wuxi, China.
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13
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Aguirre CA, Castillo VA, Llanos MN. Excess of the endocannabinoid anandamide during lactation induces overweight, fat accumulation and insulin resistance in adult mice. Diabetol Metab Syndr 2012; 4:35. [PMID: 22823902 PMCID: PMC3439322 DOI: 10.1186/1758-5996-4-35] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 07/23/2012] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Environmental conditions in early life can induce permanent physiological changes, sometimes increasing the risk of chronic diseases during adulthood. Neural and peripheral circuits controlling energy balance may be modulated during such a critical period. Since type 1 cannabinoid receptors (CB1R) have recently emerged as targets for modulating energy balance, their premature chronic activation during early life may result in long-term metabolic consequences associated to overweight/obesity. Endogenous activation of CB1R mainly occurs after binding to the endocannabinoid Anandamide (AEA). OBJECTIVE To evaluate long-term effects of AEA treatment during lactation on body weight, epididymal fat accumulation and related metabolic parameters during adulthood. DESIGN Male mice pups were orally treated with a solution of AEA (20 μg/g body weight in soy oil) or vehicle during the whole lactation period. After weaning, food intake and body weight were recorded every 10 days. Adult animals were subjected to glucose and insulin tolerance tests. Subsequently, animals were sacrificed and epididymal fat pads were extracted. Circulating levels of plasma insulin, leptin, non-sterified fatty acids (NEFA), triglyceride and cholesterol were also evaluated. RESULTS AEA-treated mice during lactation showed a significant increase in accumulated food intake, body weight and epididymal fat during adulthood when compared to control mice. When evaluating CB1R protein expression in epididymal fat, the AEA-treated group showed a 150 % increase in expression compared to the control mice. This group also displayed significantly higher levels of circulating glucose, insulin, leptin, triglycerides, cholesterol and NEFA. Moreover, a marked state of insulin resistance was an important finding in the AEA-treated group. CONCLUSION This study showed that overweight, accumulation of visceral fat and associated metabolic disturbances, such as a higher lipid profile and insulin resistance, can be programmed by a treatment with the endocannabinoid AEA during lactation in adult mice.
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Affiliation(s)
- Carolina A Aguirre
- Laboratorio de Nutrición y Regulación Metabólica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Casilla 138-11, El Líbano, 5524 Santiago, Chile
| | - Valeska A Castillo
- Laboratorio de Nutrición y Regulación Metabólica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Casilla 138-11, El Líbano, 5524 Santiago, Chile
| | - Miguel N Llanos
- Laboratorio de Nutrición y Regulación Metabólica, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Casilla 138-11, El Líbano, 5524 Santiago, Chile
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Lehr S, Hartwig S, Sell H. Adipokines: a treasure trove for the discovery of biomarkers for metabolic disorders. Proteomics Clin Appl 2011; 6:91-101. [PMID: 22213627 DOI: 10.1002/prca.201100052] [Citation(s) in RCA: 223] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/12/2011] [Accepted: 09/13/2011] [Indexed: 01/04/2023]
Abstract
Adipose tissue is a major endocrine organ, releasing signaling and mediator proteins, termed adipokines, via which adipose tissue communicates with other organs. Expansion of adipose tissue in obesity alters adipokine secretion which may contribute to the development of metabolic diseases. Consequently, this correlation has emphasized the importance to further characterize the adipocyte secretion profile, and several attempts have been made to characterize the complex nature of the adipose tissue secretome by utilizing diverse proteomic profiling approaches. Although the entirety of human adipokines is still incompletely characterized, to date more than 600 potentially secretory proteins were identified providing a rich source to identify putative novel biomarkers associated with metabolic diseases.
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Affiliation(s)
- Stefan Lehr
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Duesseldorf, Germany.
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Wang Z, Koike T, Li P, Jiang H, Natsume Y, Mu L, Chen T, Oshida Y. Effects of angiotensin II AT1 receptor inhibition and exercise training on insulin action in rats on high-fat diet. Life Sci 2011; 90:322-7. [PMID: 22210187 DOI: 10.1016/j.lfs.2011.11.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 11/09/2011] [Accepted: 11/22/2011] [Indexed: 11/27/2022]
Abstract
AIM This study was to determine whether combination of the angiotensin II AT1 receptor blocker (ARB), candesartan cilexetil, and exercise training can prevent the development of high-fat diet-induced insulin resistance. MAIN METHODS F344/NSlc rats were fed normal chow diet or high-fat (HF) diet for 7 weeks. The HF-fed rats were either administered candesartan cilexetil (5 mg·kg(-1)·day(-1)), exercise-trained, or received a combination of these 2 treatments. KEY FINDINGS Oral glucose tolerance tests (OGTT) showed that combined treatment with candesartan cilexetil and exercise increased glucose tolerance as compared with each treatment alone in HF-fed rats. Moreover, euglycemic-hyperinsulinemic clamp analysis showed improvement in glucose infusion rate with exercise training or candesartan cilexetil treatment alone, and further improvement was observed with the combination treatment. Systolic blood pressure improved with candesartan cilexetil but not with exercise alone. Finally, Glut-4 protein expression in soleus muscle was decreased with HF diet, and the expression was increased by exercise and not candesartan cilexetil treatment. SIGNIFICANCE These results suggest that the combination of candesartan cilexetil and exercise training improves insulin resistance as compared with each treatment alone.
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Affiliation(s)
- Zhonghua Wang
- Department of Sports Medicine, Graduate School of Medicine, Nagoya University, Nagoya, Japan
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Bajzer M, Olivieri M, Haas MK, Pfluger PT, Magrisso IJ, Foster MT, Tschöp MH, Krawczewski-Carhuatanta KA, Cota D, Obici S. Cannabinoid receptor 1 (CB1) antagonism enhances glucose utilisation and activates brown adipose tissue in diet-induced obese mice. Diabetologia 2011; 54:3121-31. [PMID: 21987346 PMCID: PMC8464406 DOI: 10.1007/s00125-011-2302-6] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 08/10/2011] [Indexed: 01/13/2023]
Abstract
AIMS/HYPOTHESIS We examined the physiological mechanisms by which cannabinoid receptor 1 (CB1) antagonism improves glucose metabolism and insulin sensitivity independent of its anorectic and weight-reducing effects, as well as the effects of CB1 antagonism on brown adipose tissue (BAT) function. METHODS Three groups of diet-induced obese mice received for 1 month: vehicle; the selective CB1 antagonist SR141716; or vehicle/pair-feeding. After measurements of body composition and energy expenditure, mice underwent euglycaemic-hyperinsulinaemic clamp studies to assess in vivo insulin action. In separate cohorts, we assessed insulin action in weight-reduced mice with diet-induced obesity (DIO), and the effect of CB1 antagonism on BAT thermogenesis. Surgical denervation of interscapular BAT (iBAT) was carried out in order to study the requirement for the sympathetic nervous system in mediating the effects of CB1 antagonism on BAT function. RESULTS Weight loss associated with chronic CB1 antagonism was accompanied by increased energy expenditure, enhanced insulin-stimulated glucose utilisation, and marked activation of BAT thermogenesis. Insulin-dependent glucose uptake was significantly increased in white adipose tissue and BAT, whereas glycogen synthesis was increased in liver, fat and muscle. Despite marked weight loss in the mice, SR141716 treatment did not improve insulin-mediated suppression of hepatic glucose production nor increase skeletal muscle glucose uptake. Denervation of iBAT blunted the effect of SR141716 on iBAT differentiation and insulin-mediated glucose uptake. CONCLUSIONS/INTERPRETATION Chronic CB1 antagonism markedly enhances insulin-mediated glucose utilisation in DIO mice, independent of its anorectic and weight-reducing effects. The potent effect on insulin-stimulated BAT glucose uptake reveals a novel role for CB1 receptors as regulators of glucose metabolism.
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MESH Headings
- Adipose Tissue, Brown/drug effects
- Adipose Tissue, Brown/innervation
- Adipose Tissue, Brown/metabolism
- Adipose Tissue, Brown/surgery
- Animals
- Body Composition/drug effects
- Diet, High-Fat
- Energy Metabolism/drug effects
- Gluconeogenesis/drug effects
- Glucose/metabolism
- Glycogen/biosynthesis
- Insulin/metabolism
- Liver/drug effects
- Liver/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Obese
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Piperidines/administration & dosage
- Pyrazoles/administration & dosage
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Rimonabant
- Thermogenesis/drug effects
- Weight Loss/drug effects
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Affiliation(s)
- M Bajzer
- Metabolic Diseases Institute, University of Cincinnati, 2140 East Galbraith Road, Building B, Room 332, Cincinnati, OH 45237-1625, USA
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Hutchins-Wiese HL, Li Y, Hannon K, Watkins BA. Hind limb suspension and long-chain omega-3 PUFA increase mRNA endocannabinoid system levels in skeletal muscle. J Nutr Biochem 2011; 23:986-93. [PMID: 22051448 DOI: 10.1016/j.jnutbio.2011.05.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 04/18/2011] [Accepted: 05/13/2011] [Indexed: 11/28/2022]
Abstract
Muscle disuse has numerous physiological consequences that end up with significant catabolic metabolism and ultimately tissue atrophy. What is not known is how muscle atrophy affects the endocannabinoid (EC) system. Arachidonic acid (AA) is the substrate for anandamide (AEA) and 2-arachidonylgycerol (2-AG), which act as agonists for cannabinoid receptors CB1 and CB2 found in muscle. Diets with n-3 polyunsaturated fatty acids (PUFA) have been shown to reduce tissue levels of AA, AEA and 2-AG. Therefore, we hypothesized that hind limb suspension (HS)-induced muscle atrophy and intake of n-3 PUFA will change mRNA levels of the EC system. Mice were randomized and assigned to a moderate n-3 PUFA [11.7 g/kg eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA)], high n-3 PUFA (17.6 g/kg EPA+DHA) or control diets for 12 days and then subjected to HS or continued weight bearing (WB) for 14 days. HS resulted in body weight, epididymal fat pad and quadriceps muscle loss compared to WB. Compared to WB, HS had greater mRNA levels of AEA and 2-AG synthesis enzymes and CB2 in the atrophied quadriceps muscle. The high n-3 PUFA diet resulted in greater mRNA levels of EC synthesis enzymes, and CB1 and CB2. The higher mRNA levels for EC with HS and dietary n-3 PUFA suggest that muscle disuse and diet induce changes in the EC system to sensitize muscle in response to metabolic and physiological consequences of atrophy.
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Marchionne EM, Diamond-Stanic MK, Prasonnarong M, Henriksen EJ. Chronic renin inhibition with aliskiren improves glucose tolerance, insulin sensitivity, and skeletal muscle glucose transport activity in obese Zucker rats. Am J Physiol Regul Integr Comp Physiol 2011; 302:R137-42. [PMID: 22049232 DOI: 10.1152/ajpregu.00448.2011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We have demonstrated previously that overactivity of the renin-angiotensin system (RAS) is associated with whole body and skeletal muscle insulin resistance in obese Zucker (fa/fa) rats. Moreover, this obesity-associated insulin resistance is reduced by treatment with angiotensin-converting enzyme inhibitors or angiotensin receptor (type 1) blockers. However, it is currently unknown whether specific inhibition of renin itself, the rate-limiting step in RAS functionality, improves insulin action in obesity-associated insulin resistance. Therefore, the present study assessed the effect of chronic, selective renin inhibition using aliskiren on glucose tolerance, whole body insulin sensitivity, and insulin action on the glucose transport system in skeletal muscle of obese Zucker rats. Obese Zucker rats were treated for 21 days with either vehicle or aliskiren (50 mg/kg body wt ip). Renin inhibition was associated with a significant lowering (10%, P < 0.05) of resting systolic blood pressure and induced reductions in fasting plasma glucose (11%) and free fatty acids (46%) and homeostatic model assessment for insulin resistance (13%). Glucose tolerance (glucose area under the curve) and whole body insulin sensitivity (inverse of the glucose-insulin index) during an oral glucose tolerance test were improved by 15% and 16%, respectively, following chronic renin inhibition. Moreover, insulin-stimulated glucose transport activity in isolated soleus muscle of renin inhibitor-treated animals was increased by 36% and was associated with a 2.2-fold greater Akt Ser(473) phosphorylation. These data provide evidence that chronic selective inhibition of renin activity leads to improvements in glucose tolerance and whole body insulin sensitivity in the insulin-resistant obese Zucker rat. Importantly, chronic renin inhibition is associated with upregulation of insulin action on skeletal muscle glucose transport, and it may involve improved Akt signaling. These data support the strategy of targeting the RAS to improve both blood pressure regulation and insulin action in conditions of insulin resistance.
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Affiliation(s)
- Elizabeth M Marchionne
- Muscle Metabolism Laboratory, Department of Physiology, University of Arizona College of Medicine, Tucson, 85721-0093, USA
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Sheng L, Cho KW, Zhou Y, Shen H, Rui L. Lipocalin 13 protein protects against hepatic steatosis by both inhibiting lipogenesis and stimulating fatty acid β-oxidation. J Biol Chem 2011; 286:38128-38135. [PMID: 21908604 DOI: 10.1074/jbc.m111.256677] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Obesity is associated with hepatic steatosis, partially due to increased lipogenesis and decreased fatty acid β-oxidation in the liver; however, the underlying mechanism of abnormal lipid metabolism is not fully understood. We reported previously that obesity is associated with LCN13 (lipocalin 13) deficiency. LCN13 is a lipocalin family member involved in glucose metabolism, and LCN13 deficiency appears to contribute to hyperglycemia in obese mice. Here, we show that LCN13 is also an important regulator of lipogenesis and β-oxidation in the liver. In primary hepatocytes, recombinant LCN13 directly suppressed lipogenesis and increased fatty acid β-oxidation, whereas neutralization of endogenous LCN13 had an opposite effect. Transgenic overexpression of LCN13 protected against hepatic steatosis in mice with either dietary or genetic (ob/ob) obesity. LCN13 transgenic overexpression also improved hyperglycemia, glucose intolerance, and insulin resistance in ob/ob mice. Short-term LCN13 overexpression via an adenovirus-mediated gene transfer similarly attenuated hepatic steatosis in db/db mice. LCN13 inhibited the expression of important lipogenic genes and stimulated the genes that promote β-oxidation. These results suggest that LCN13 decreases liver lipid levels by both inhibiting hepatic lipogenesis and stimulating β-oxidation. LCN13 deficiency is likely to contribute to fatty liver disease in obese mice.
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Affiliation(s)
- Liang Sheng
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Kae Won Cho
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Yingjiang Zhou
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Hong Shen
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Liangyou Rui
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan 48109.
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Cohen G, Riahi Y, Sasson S. Lipid peroxidation of poly-unsaturated fatty acids in normal and obese adipose tissues. Arch Physiol Biochem 2011; 117:131-9. [PMID: 21395403 DOI: 10.3109/13813455.2011.557387] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Adipose tissues function as the primary storage compartment of fatty acids and as an endocrine organ that affects peripheral tissues. Many of adipose tissue-derived factors, often termed adipokines, have been discovered in recent years. The synthesis and secretion of these factors vary in different depots of adipose tissues. Excessive lipid accumulation in adipocytes induces inflammatory processes by up-regulating the expression and release of pro-inflammatory cytokines. In addition, activated macrophages in the obese adipose tissue release inflammatory cytokines. Adipose tissue inflammation has also been linked to an enhanced metabolism of polyunsaturated fatty acids (PUFAs). The non-enzymatic peroxidation of PUFAs and of their 12/15-lipoxygenase-derived hydroperoxy metabolites leads to the generation of the reactive aldehyde species 4-hydroxyalkenals. This review shows that 4-hydroxyalkenals, in particular 4-hydroxynonenal, play a key role in lipid storage homeostasis in normal adipocytes. Nonetheless, in the obese adipose tissue an increased production of 4-hydroxyalkenals contributes to the inflamed phenotype.
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Affiliation(s)
- G Cohen
- Institute for Drug Research, Department of Pharmacology, School of Pharmacy, Faculty of Medicine, The Hebrew University, Jerusalem, Israel
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Abstract
Over the last decades, substantial progress has been made in defining the molecular events and relevant tissues controlling insulin action and the potential defects that lead to insulin resistance and later on Type 2 diabetes mellitus (T2DM). Mitochondrial dysfunction has been postulated as a common mechanism implicated in the development of insulin resistance and T2DM aetiology. Since then there has been growing interest in this area of research and many studies have addressed whether mitochondrial function/dysfunction is implicated in the progression of T2DM or if it is just a consequence. Mitochondria are adjusted to the specific needs of the tissue and to the environmental interactions or pathophysiological state that it encounters. This review offers a current state of the subject in a tissue specific approach. We will focus our attention on skeletal muscle, liver, and white adipose tissue as the main insulin sensitive organs. Hypothalamic mitochondrial function will be also discussed.
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Affiliation(s)
- Pablo M Garcia-Roves
- Diabetes and Obesity Laboratory, Institute for Biomedical Research August Pi i Sunyer (IDIBAPS) and Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Barcelona, Spain.
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Jensen J, Ruge T, Lai YC, Svensson MK, Eriksson JW. Effects of adrenaline on whole-body glucose metabolism and insulin-mediated regulation of glycogen synthase and PKB phosphorylation in human skeletal muscle. Metabolism 2011; 60:215-26. [PMID: 20153492 DOI: 10.1016/j.metabol.2009.12.028] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Revised: 12/23/2009] [Accepted: 12/28/2009] [Indexed: 11/20/2022]
Abstract
In the present study, we investigated the effect of adrenaline on insulin-mediated regulation of glucose and fat metabolism with focus on regulation of skeletal muscle PKB, GSK-3, and glycogen synthase (GS) phosphorylation. Ten healthy subjects (5 men and 5 women) received a 240-minute intravenous infusion of adrenaline (0.05 μg/[kg min]) or saline; after 120 minutes, a hyperinsulinemic-euglycemic clamp was added. Adrenaline infusion increased blood glucose concentration by approximately 50%, but the hyperinsulinemic clamp normalized blood glucose within 30 minutes. Glucose infusion rate during the last hour was approximately 60% lower during adrenaline infusion compared with saline (4.3 ± 0.5 vs 11.2 ± 0.6 mg/kg lean body mass per minute). Insulin increased PKB Ser⁴⁷³, PKB Thr³⁰⁸, and GSK-3β Ser⁹ phosphorylation in skeletal muscles; coinfusion of adrenaline did not influence insulin-stimulated PKB and GSK-3 phosphorylation. Adrenaline alone did not influence phosphorylation of PKB and GSK-3β. Insulin increased GS fractional activity and decreased GS Ser⁶⁴¹ and Ser⁶⁴⁵,⁶⁴⁹,⁶⁵³,⁶⁵⁷ phosphorylation. In the presence of adrenaline, insulin did neither activate GS nor dephosphorylate GS Ser⁶⁴¹. Surprisingly, GS Ser⁷ phosphorylation was not influenced by adrenaline. Adrenaline increased plasma lactate concentration; and muscle glycogen content was reduced in skeletal muscle the day after adrenaline infusion, supporting that insulin does not stimulate glycogen synthesis in skeletal muscles when adrenaline is present. In conclusion, adrenaline did not influence basal or insulin-stimulated PKB and GSK-3β phosphorylation in muscles, but completely blocked insulin-mediated GS activation and Ser⁶⁴¹ dephosphorylation. Still, insulin normalized adrenaline-mediated hyperglycemia.
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Affiliation(s)
- Jørgen Jensen
- Department of Physiology, National Institute of Occupational Health, P.O. Box 8149 Dep, N-0033 Oslo, Norway.
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Lindborg KA, Jacob S, Henriksen EJ. Effects of Chronic Antagonism of Endocannabinoid-1 Receptors on Glucose Tolerance and Insulin Action in Skeletal Muscles of Lean and Obese Zucker Rats. Cardiorenal Med 2011; 1:31-44. [PMID: 22258464 DOI: 10.1159/000322826] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/01/2010] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND/AIMS Antagonism of the endocannabinoid receptor-1 (CB1R) directly improves whole-body metabolic parameters of insulin resistance. The present investigation determined the effects of chronic CB1R antagonism on whole-body and skeletal-muscle insulin action in insulin-sensitive lean and insulin-resistant obese Zucker rats. METHODS Animals were either fed ad libitum or in pairs, or treated with SR141716 (10 mg/kg i.p. for 14 days). RESULTS Food intake was significantly reduced (p < 0.05) after initial SR141716 treatment and remained decreased in both lean and obese animals until day 13. Fasting plasma glucose decreased (24%) and insulin increased (43%) in lean SR141716-treated (24%) rats compared to lean ad libitum-fed controls, but not in the corresponding obese groups. Fasting plasma free fatty acids were reduced by CB1R antagonism in lean (21%) and obese (42%) animals. Whole-body insulin sensitivity was increased (36%) in obese SR141716-treated rats compared to obese ad libitum-fed controls, which was associated with reduced insulin secretion during an oral glucose tolerance test. Insulin-stimulated glucose transport activity in the soleus was greatest in the respective SR141716-treated lean and obese groups compared to the corresponding ad libitum- and pair-fed controls. Chronic SR141716 treatment did not induce alterations in signaling factors associated with the regulation of glucose transport [protein kinase B (Akt), glycogen synthase kinase-3β, 5'-AMP-dependent protein kinase, or p38 mitogen-activated protein kinase] in the soleus. CONCLUSIONS These results indicate that, while the chronic treatment with CB1R antagonism markedly diminished food intake in lean and obese Zucker rats, there are also significant metabolic improvements in whole-body and skeletal-muscle insulin action mediated by CB1R antagonism through mechanisms independent of reduced caloric intake.
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Lang CH. Potential therapeutic role of resistance training in diabetes: a contribution by the 2009 recipient of the APS New Investigator Award. Am J Physiol Endocrinol Metab 2011; 300:E1-2. [PMID: 21062958 DOI: 10.1152/ajpendo.00608.2010] [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: 11/22/2022]
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Lipocalin-13 regulates glucose metabolism by both insulin-dependent and insulin-independent mechanisms. Mol Cell Biol 2010; 31:450-7. [PMID: 21135134 DOI: 10.1128/mcb.00459-10] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Insulin sensitivity is impaired in obesity, and insulin resistance is the primary risk factor for type 2 diabetes. Here we show that lipocalin-13 (LCN13), a lipocalin superfamily member, is a novel insulin sensitizer. LCN13 was secreted by multiple cell types. Circulating LCN13 was markedly reduced in mice with obesity and type 2 diabetes. Three distinct approaches were used to increase LCN13 levels: LCN13 transgenic mice, LCN13 adenoviral infection, and recombinant LCN13 administration. Restoration of LCN13 significantly ameliorated hyperglycemia, insulin resistance, and glucose intolerance in mice with obesity. LCN13 enhanced insulin signaling not only in animals but also in cultured adipocytes. Recombinant LCN13 increased the ability of insulin to stimulate glucose uptake in adipocytes and to suppress hepatic glucose production (HGP) in primary hepatocyte cultures. Additionally, LCN13 alone was able to suppress HGP, whereas neutralization of LCN13 increased HGP in primary hepatocyte cultures. These data suggest that LCN13 regulates glucose metabolism by both insulin-dependent and insulin-independent mechanisms. LCN13 and LCN13-related molecules may be used to treat insulin resistance and type 2 diabetes.
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Karvela A, Rojas-Gil AP, Samkinidou E, Papadaki H, Pappa A, Georgiou G, Spiliotis BE. Endocannabinoid (EC) receptor, CB1, and EC enzymes' expression in primary adipocyte cultures of lean and obese pre-pubertal children in relation to adiponectin and insulin. J Pediatr Endocrinol Metab 2010; 23:1011-24. [PMID: 21158212 DOI: 10.1515/jpem.2010.162] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AIM The over-expression of CB1 in adult obesity is associated with insulin resistance (IR),but it is not elucidated in childhood obesity. We studied CB1 and endocannabinoid enzymes (EE), Adiponectin (Ad), and Insulin (SI) in lean and obese pre-pubertal (PP) children. METHODS CB1 mRNA and protein (Pr) expression were studied by RT-PCR, western immunoblotting and immunohistochemistry in primary cultures of adipose tissue. The EE(NAPE-PLD, DAGL-alpha, FAAH, MAGL) expression was assessed by Real-Time PCR. Ad and SI were measured by ELISA and IR by HOMA-IR index. RESULTS In the older obese vs older lean children: (1) CB1 Pr was decreased, (2) FAAHmRNA and DAGL-alpha mRNA were increased. Ad was decreased and SI and HOMA-IR increased in the older PP children. CONCLUSIONS Increased CB1 and decreased adiponectin in older lean PP children may facilitate fat deposition and "physiologic" IR necessary for the increased body growth of puberty. The reduced expression of CB1 in the older obese may be an attempt to reduce lipogenesis to avoid greater insulin resistance.
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Affiliation(s)
- Alexia Karvela
- Research Laboratory of the Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, University of Patras School of Medicine, Patras, Greece
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