51
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Fujitani M, Matsumura S, Masuda D, Yamashita S, Fushiki T, Inoue K. CD36, but not GPR120, is required for efficient fatty acid utilization during endurance exercise. Biosci Biotechnol Biochem 2014; 78:1871-8. [PMID: 25070011 DOI: 10.1080/09168451.2014.940835] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Fatty acids (FA) are an important energy source during exercise. In addition to its role as an energy supply for skeletal muscle, FA may activate signaling pathways that regulate gene expression. FA translocase/cluster of differentiation 36 (CD36) and G protein-coupled receptor GPR120 are long-chain FA receptors. In this study, we investigated the impact of CD36 or GPR120 deletion on energy metabolism during exercise. CD36 has been reported to facilitate cellular transport and oxidation of FA during endurance exercise. We show that CD36 deletion decreased exogenous FA oxidation during exercise, using a combination of (13)C-labeled FA oxidation measurement and indirect calorimetry. In contrast, GPR120 deletion had no observable effect on energy metabolism during exercise. Our results further substantiate that CD36-mediated FA transport plays an essential role in efficient FA oxidation during exercise.
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Affiliation(s)
- Mina Fujitani
- a Laboratory of Nutrition Chemistry, Graduate School of Agriculture , Kyoto University , Sakyou-ku , Japan
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52
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van Bilsen M, Planavila A. Fatty acids and cardiac disease: fuel carrying a message. Acta Physiol (Oxf) 2014; 211:476-90. [PMID: 24773697 DOI: 10.1111/apha.12308] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 04/02/2014] [Accepted: 04/25/2014] [Indexed: 12/20/2022]
Abstract
From the viewpoint of the prevention of cardiovascular disease (CVD) burden, there has been a continuous interest in the detrimental effects of the Western-type high-fat diet for more than half a century. More recently, this general view has been subject to change as epidemiological studies showed that replacing fat by carbohydrate may even be worse and that various polyunsaturated fatty acids (FA) have beneficial rather than detrimental effects on CVD outcome. At the same time, advances in lipid biology have provided insight into the mechanisms by which the different lipid components of the Western diet affect the cardiovascular system. In fact, this still is a rapidly growing field of research and in recent years novel FA derivatives and FA receptors have been discovered. This includes fish-oil derived FA-derivatives with anti-inflammatory properties, the so-called resolvins, and various G-protein-coupled receptors that recognize FA as ligands. In the present review, we will extensively discuss the role of FA and their metabolites on cardiac disease, with special emphasis on the role of the different saturated and polyunsaturated FA and their respective metabolites in cellular signal transduction and the possible implications for the development of cardiac hypertrophy and cardiac failure.
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Affiliation(s)
- M. van Bilsen
- Department of Physiology; Cardiovascular Research Institute Maastricht; Maastricht University; Maastricht the Netherlands
| | - A. Planavila
- Departament de Bioquímica i Biologia Molecular; Institut de Biomedicina de la Universitat de Barcelona (IBUB); Universitat de Barcelona and CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN); Barcelona Spain
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53
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Rodriguez-Pacheco F, Garcia-Serrano S, Garcia-Escobar E, Gutierrez-Repiso C, Garcia-Arnes J, Valdes S, Gonzalo M, Soriguer F, Moreno-Ruiz FJ, Rodriguez-Cañete A, Gallego-Perales JL, Martinez-Ferriz A, Rojo-Martínez G, Garcia-Fuentes E. Effects of obesity/fatty acids on the expression of GPR120. Mol Nutr Food Res 2014; 58:1852-60. [DOI: 10.1002/mnfr.201300666] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 02/10/2014] [Accepted: 04/02/2014] [Indexed: 01/28/2023]
Affiliation(s)
- Francisca Rodriguez-Pacheco
- Unidad de Gestion Clinica de Endocrinogía y Nutrición; Instituto de Investigaciones Biomédicas de Málaga (IBIMA); Hospital Regional Universitario; Malaga Spain
- CIBERDEM, Instituto de Salud Carlos III; Malaga Spain
| | - Sara Garcia-Serrano
- Unidad de Gestion Clinica de Endocrinogía y Nutrición; Instituto de Investigaciones Biomédicas de Málaga (IBIMA); Hospital Regional Universitario; Malaga Spain
- CIBERDEM, Instituto de Salud Carlos III; Malaga Spain
| | - Eva Garcia-Escobar
- Unidad de Gestion Clinica de Endocrinogía y Nutrición; Instituto de Investigaciones Biomédicas de Málaga (IBIMA); Hospital Regional Universitario; Malaga Spain
- CIBERDEM, Instituto de Salud Carlos III; Malaga Spain
| | - Carolina Gutierrez-Repiso
- Unidad de Gestion Clinica de Endocrinogía y Nutrición; Instituto de Investigaciones Biomédicas de Málaga (IBIMA); Hospital Regional Universitario; Malaga Spain
| | - Juan Garcia-Arnes
- Unidad de Gestion Clinica de Endocrinogía y Nutrición; Instituto de Investigaciones Biomédicas de Málaga (IBIMA); Hospital Regional Universitario; Malaga Spain
| | - Sergio Valdes
- Unidad de Gestion Clinica de Endocrinogía y Nutrición; Instituto de Investigaciones Biomédicas de Málaga (IBIMA); Hospital Regional Universitario; Malaga Spain
- CIBERDEM, Instituto de Salud Carlos III; Malaga Spain
| | - Montserrat Gonzalo
- Unidad de Gestion Clinica de Endocrinogía y Nutrición; Instituto de Investigaciones Biomédicas de Málaga (IBIMA); Hospital Regional Universitario; Malaga Spain
| | - Federico Soriguer
- Unidad de Gestion Clinica de Endocrinogía y Nutrición; Instituto de Investigaciones Biomédicas de Málaga (IBIMA); Hospital Regional Universitario; Malaga Spain
- CIBERDEM, Instituto de Salud Carlos III; Malaga Spain
- CIBEROBN; Instituto de Salud Carlos III; Malaga Spain
| | - Francisco J. Moreno-Ruiz
- Unidad de Gestion Clínica de Cirugía General; Digestiva y Trasplantes; Instituto de Investigaciones Biomédicas de Málaga (IBIMA); Hospital Regional Universitario; Malaga Spain
| | - Alberto Rodriguez-Cañete
- Unidad de Gestion Clínica de Cirugía General; Digestiva y Trasplantes; Instituto de Investigaciones Biomédicas de Málaga (IBIMA); Hospital Regional Universitario; Malaga Spain
| | - Jose L. Gallego-Perales
- Unidad de Gestion Clínica de Cirugía General; Digestiva y Trasplantes; Instituto de Investigaciones Biomédicas de Málaga (IBIMA); Hospital Regional Universitario; Malaga Spain
| | - Abelardo Martinez-Ferriz
- Unidad de Gestion Clínica de Cirugía General; Digestiva y Trasplantes; Instituto de Investigaciones Biomédicas de Málaga (IBIMA); Hospital Regional Universitario; Malaga Spain
| | - Gemma Rojo-Martínez
- Unidad de Gestion Clinica de Endocrinogía y Nutrición; Instituto de Investigaciones Biomédicas de Málaga (IBIMA); Hospital Regional Universitario; Malaga Spain
- CIBERDEM, Instituto de Salud Carlos III; Malaga Spain
- CIBEROBN; Instituto de Salud Carlos III; Malaga Spain
| | - Eduardo Garcia-Fuentes
- Unidad de Gestion Clinica de Endocrinogía y Nutrición; Instituto de Investigaciones Biomédicas de Málaga (IBIMA); Hospital Regional Universitario; Malaga Spain
- CIBERDEM, Instituto de Salud Carlos III; Malaga Spain
- CIBEROBN; Instituto de Salud Carlos III; Malaga Spain
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54
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Abstract
The beneficial roles of omega-3 fatty acids (ω3-FAs) on obesity, type 2 diabetes, and other metabolic diseases are well known. Most of these effects can be explained by their anti-inflammatory effects triggered through their receptor, free fatty acid receptor 4 (FFAR4) activation. Although the whole mechanism of action is not fully described yet, it has been shown that stimulation of ω3-FA to FFAR4 is followed by receptor phosphorylation. This makes FFAR4 to be capable of interacting with β-arrestin-2, which in turn, results in association of β-arrestin-2 with TAB1. This stealing of an important partaker of the inflammatory cascade leads to interruption of the pathway, resulting in reduced inflammation. Besides this regulation of the anti-inflammatory response, FFAR4 signaling also has been shown to regulate glucose homeostasis, adiposity, gastrointestinal peptide secretion, and taste preference. In this review, we summarize the current knowledge about the interaction of ω3-FAs with FFAR4 and the consequent opportunities for the application of ω3-FAs and possible FFAR4 targets.
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Affiliation(s)
- Da Young Oh
- Division of Endocrinology and Metabolism, Department of Medicine, University of California San Diego, La Jolla, CA, USA
- *Correspondence: Da Young Oh, Division of Endocrinology and Metabolism, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA e-mail:
| | - Evelyn Walenta
- Division of Endocrinology and Metabolism, Department of Medicine, University of California San Diego, La Jolla, CA, USA
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55
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Cornall LM, Mathai ML, Hryciw DH, McAinch AJ. GPR120 agonism as a countermeasure against metabolic diseases. Drug Discov Today 2013; 19:670-9. [PMID: 24315954 DOI: 10.1016/j.drudis.2013.11.021] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 10/30/2013] [Accepted: 11/28/2013] [Indexed: 12/31/2022]
Abstract
Obesity, type 2 diabetes mellitus and cardiovascular disease are at epidemic proportions in developed nations globally, representing major causes of ill-health and premature death. The search for drug targets to counter the growing prevalence of metabolic diseases has uncovered G-protein-coupled receptor 120 (GPR120). GPR120 agonism has been shown to improve inflammation and metabolic health on a systemic level via regulation of adiposity, gastrointestinal peptide secretion, taste preference and glucose homeostasis. Therefore, GPR120 agonists present as a novel therapeutic option that could be exploited for the treatment of impaired metabolic health. This review summarizes the current knowledge of GPR120 functionality and the potential applications of GPR120-specific agonists for the treatment of disease states such as obesity, type 2 diabetes mellitus and cardiovascular disease.
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Affiliation(s)
- Lauren M Cornall
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, Melbourne 8001, Australia
| | - Michael L Mathai
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, Melbourne 8001, Australia
| | - Deanne H Hryciw
- Department of Physiology, The University of Melbourne, Melbourne 3010, Australia
| | - Andrew J McAinch
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, Melbourne 8001, Australia.
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56
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Cornall LM, Mathai ML, Hryciw DH, McAinch AJ. The therapeutic potential of GPR43: a novel role in modulating metabolic health. Cell Mol Life Sci 2013; 70:4759-70. [PMID: 23852543 PMCID: PMC11113592 DOI: 10.1007/s00018-013-1419-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/09/2013] [Accepted: 06/28/2013] [Indexed: 02/07/2023]
Abstract
GPR43 is a receptor for short-chain fatty acids. Preliminary data suggest a putative role for GPR43 in regulating systemic health via processes including inflammation, carcinogenesis, gastrointestinal function, and adipogenesis. GPR43 is involved in secretion of gastrointestinal peptides, which regulate appetite and gastrointestinal motility. This suggests GPR43 may have a role in weight control. Moreover, GPR43 regulates plasma lipid profile and inflammatory processes, which further indicates that GPR43 could have the ability to modulate the etiology and pathogenesis of metabolic diseases such as obesity, type 2 diabetes mellitus, and cardiovascular disease. This review summarizes the current evidence regarding the ability of GPR43 to mediate both systemic and tissue specific functions and how GPR43 may be modulated in the treatment of metabolic disease.
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Affiliation(s)
- Lauren M Cornall
- Biomedical and Lifestyle Diseases Unit, College of Health and Biomedicine, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia,
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57
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Charradi K, Mahmoudi M, Elkahoui S, Limam F, Aouani E. Grape seed and skin extract mitigates heart and liver oxidative damage induced by a high-fat diet in the rat: gender dependency. Can J Physiol Pharmacol 2013; 91:1076-85. [PMID: 24289079 DOI: 10.1139/cjpp-2013-0225] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Obesity is a public health problem contributing to morbidity and mortality from metabolic syndrome. It has long been recognized that there is a gender dependency in several obesity-related health risks. Using a high fat diet (HFD) to induce obesity in Wistar rats, we studied the gender dependency of fat-induced oxidative stress in the heart and liver, with a special emphasis on the distribution of transition metals, as well as the protective effects of grape seed and skin extract (GSSE). HFD induced obesity in both male and female rats, characterized by increased body weight as well as relative liver mass in both genders, and increased relative heart mass in the males only. HFD also provoked the accumulation of triglycerides and total cholesterol into the male hearts, and into the livers of both genders. HFD induced oxidative stress in the male hearts and also in the livers of both genders. Furthermore, HFD affected cardiac levels of copper in the males, and hepatic levels of copper and zinc in both genders, whereas HFD affected free iron in the male hearts and female livers, specifically. In conclusion, HFD treatment altered transition metal homeostasis more drastically in the male heart than in the female liver, and GSSE efficiently protected these organs against fat-induced disturbances, regardless of gender.
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Affiliation(s)
- Kamel Charradi
- a Laboratoire des Substances Bioactives (LSBA), Centre de Biotechnologie de Borj Cedria, BP-901, 2050 Hammam-Lif, Tunisie
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58
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High-fat diet induced an oxidative stress in white adipose tissue and disturbed plasma transition metals in rat: prevention by grape seed and skin extract. J Physiol Sci 2013; 63:445-55. [DOI: 10.1007/s12576-013-0283-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 07/22/2013] [Indexed: 12/22/2022]
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59
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Resolution of inflammation: mechanisms and opportunity for drug development. Pharmacol Ther 2013; 139:189-212. [PMID: 23583354 DOI: 10.1016/j.pharmthera.2013.04.006] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 04/01/2013] [Indexed: 12/12/2022]
Abstract
Inflammation is a beneficial host reaction to tissue damage and has the essential primary purpose of restoring tissue homeostasis. Inflammation plays a major role in containing and resolving infection and may also occur under sterile conditions. The cardinal signs of inflammation dolor, calor, tumor and rubor are intrinsically associated with events including vasodilatation, edema and leukocyte trafficking into the site of inflammation. If uncontrolled or unresolved, inflammation itself can lead to further tissue damage and give rise to chronic inflammatory diseases and autoimmunity with eventual loss of organ function. It is now evident that the resolution of inflammation is an active continuous process that occurs during an acute inflammatory episode. Successful resolution requires activation of endogenous programs with switch from production of pro-inflammatory towards pro-resolving molecules, such as specific lipid mediators and annexin A1, and the non-phlogistic elimination of granulocytes by apoptosis with subsequent removal by surrounding macrophages. These processes ensure rapid restoration of tissue homeostasis. Here, we review recent advances in the understanding of resolution of inflammation, highlighting the pharmacological strategies that may interfere with the molecular pathways which control leukocyte survival and clearance. Such strategies have proved beneficial in several pre-clinical models of inflammatory diseases, suggesting that pharmacological modulation of the resolution process may be useful for the treatment of chronic inflammatory diseases in humans.
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60
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Abstract
Fatty acid regulation of hepatic gene transcription was first reported in the early 1990s. Several transcription factors have been identified as targets of fatty acid regulation. This regulation is achieved by direct fatty acid binding to the transcription factor or by indirect mechanisms where fatty acids regulate signaling pathways controlling the expression of transcription factors or the phosphorylation, ubiquitination, or proteolytic cleavage of the transcription factor. Although dietary fatty acids are well-established regulators of hepatic transcription factors, emerging evidence indicates that endogenously generated fatty acids are equally important in controlling transcription factors in the context of glucose and lipid homeostasis. Our first goal in this review is to provide an up-to-date examination of the molecular and metabolic bases of fatty acid regulation of key transcription factors controlling hepatic metabolism. Our second goal is to link these mechanisms to nonalcoholic fatty liver disease (NAFLD), a growing health concern in the obese population.
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Affiliation(s)
- Donald B Jump
- Nutrition Program, School of Biological and Population Health Science, Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA.
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61
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Cornall LM, Mathai ML, Hryciw DH, Simcocks AC, O'Brien PE, Wentworth JM, McAinch AJ. GPR119 regulates genetic markers of fatty acid oxidation in cultured skeletal muscle myotubes. Mol Cell Endocrinol 2013; 365:108-18. [PMID: 23069642 DOI: 10.1016/j.mce.2012.10.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 10/01/2012] [Accepted: 10/03/2012] [Indexed: 12/16/2022]
Abstract
Gene knockout and agonist studies indicate that activation of the G protein-coupled receptor, GPR119, protects against diet-induced obesity and insulin resistance. It is not known if GPR119 activation in skeletal muscle mediates these effects. To address this uncertainty, we measured GPR119 expression in skeletal muscle and determined the effects of PSN632408, a GPR119 agonist, on the expression of genes and proteins required for fatty acid and glucose oxidation in cultured myotubes. GPR119 expression was readily detected in rat skeletal muscle and mRNAs were induced by 12 weeks of high-fat feeding. Treatment of cultured mouse C₂C₁₂ myotubes with 5 μM PSN632408 or 0.5 mM palmitate reduced expression of mRNAs encoding fatty acid oxidation genes to similar extents. More so, treatment with PSN632408 decreased AMPKα (Thr172 phosphorylation) activity in the absence of palmitate and ACC (Ser79 phosphorylation) activity in the presence of palmitate. In human primary myotubes PSN632408 decreased expression of PDK4 and AMPKα2 mRNA in myotubes derived from obese donors. These data suggest GPR119 activation in skeletal muscle may impair fatty acid and glucose oxidation.
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MESH Headings
- Acids, Heterocyclic/pharmacology
- Adult
- Animals
- Body Mass Index
- Cells, Cultured
- Clone Cells
- Fatty Acids, Nonesterified/metabolism
- Female
- Gene Expression Regulation/drug effects
- Genetic Markers
- Glucose/metabolism
- Humans
- Male
- Mice
- Middle Aged
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Obesity, Morbid/genetics
- Obesity, Morbid/metabolism
- Obesity, Morbid/pathology
- Oxadiazoles/pharmacology
- Random Allocation
- Rats
- Rats, Sprague-Dawley
- Receptors, G-Protein-Coupled/agonists
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
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Affiliation(s)
- L M Cornall
- Biomedical and Lifestyle Diseases Unit, School of Biomedical and Health Sciences, Victoria University, Melbourne 8001, Australia.
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62
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Mo XL, Wei HK, Peng J, Tao YX. Free Fatty Acid Receptor GPR120 and Pathogenesis of Obesity and Type 2 Diabetes Mellitus. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 114:251-76. [DOI: 10.1016/b978-0-12-386933-3.00007-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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63
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Wanders D, Graff EC, Judd RL. Effects of high fat diet on GPR109A and GPR81 gene expression. Biochem Biophys Res Commun 2012; 425:278-83. [PMID: 22842580 DOI: 10.1016/j.bbrc.2012.07.082] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 07/17/2012] [Indexed: 11/27/2022]
Abstract
GPR109A (PUMA-G, NIACR1, HCA(2)) and GPR81 (HCA(1)) are G protein-coupled receptors located predominantly on adipocytes that mediate anti-lipolytic effects. These cell surface receptors give the adipocyte the ability to "sense" metabolic changes in the environment and respond through lipolytic regulation and release of products including free fatty acids and pro- or anti-inflammatory adipokines. The endogenous ligands for GPR109A and GPR81 are β-hydroxybutyrate and lactate, respectively, both of which are hydroxycarboxylic acids and intermediates of energy metabolism. Circulating β-hydroxybutyrate levels are increased during a 2-3 day fast and prolonged starvation, while lactate levels are elevated during times of intense exercise. Therefore, regulation of expression of these receptors is crucial for the metabolic sensing ability of the adipocyte and ultimately whole body energy homeostasis. We investigated the effects of high fat diet-induced obesity on expression of GPR109A and GPR81. Sixteen male C57BL/6 mice were placed on a control (10% kcal fat; n=8) or a high fat (60% kcal fat; n=8) diet for 11 weeks. Diet-induced obesity significantly reduced GPR109A and GPR81 gene expression in epididymal fat pads. This decrease in GPR109A and GPR81 gene expression was positively correlated with a decrease in adipose tissue PPARγ gene expression. In contrast, acute treatment of both 3T3-L1 adipocytes and RAW 264.7 macrophages with lipopolysaccharide significantly increased GPR109A gene expression, but had no effect on GPR81 expression in 3T3-L1 adipocytes. In conclusion, chronic obesity reduces GPR109A and GPR81 expression in the adipose tissue, while acute in vitro LPS treatment increases expression of GPR109A in adipocytes and macrophages.
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Affiliation(s)
- Desiree Wanders
- Department of Anatomy, Physiology and Pharmacology, Auburn University, 219 Greene Hall, Auburn, AL 36849-5518, USA
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64
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Palmitate contributes to insulin resistance through downregulation of the Src-mediated phosphorylation of Akt in C2C12 myotubes. Biosci Biotechnol Biochem 2012; 76:1356-61. [PMID: 22785470 DOI: 10.1271/bbb.120107] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The mechanisms of free fatty acid (FFA)-induced peripheral insulin resistance remain elusive. This study aimed to investigate the effect of palmitate, a saturated fatty acid, on glucose metabolism in C2C12 myotubes, and to explore the underlying mechanisms. In it, palmitate decreased insulin-stimulated glucose uptake and consumption in a dose-dependent manner, and it reduced the insulin-stimulated phosphorylation of Akt at Thr308 and Ser473, but had no effect on the protein expression of PI3K-p85 or the activity of PI3K. Additionally, it inhibited the insulin-stimulated phosphorylation of Src at Tyr416, causing a reduction in the Src-mediated phosphorylation of Akt. Inhibition of Src by PP2 resulted in decreases in insulin-stimulated glucose uptake and phosphorylation of Src at Tyr416 and Akt at Thr308 and Ser473. The findings indicate that palmitate contributes to insulin resistance by inhibiting the Src-mediated phosphorylation of Akt in C2C12 myotubes, and this provides insight into the molecular mechanisms of FFA-induced insulin resistance.
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