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Iñigo MR, Amorese AJ, Tarpey MD, Balestrieri NP, Jones KG, Patteson DJ, Jackson KC, Torres MJ, Lin CT, Smith CD, Heden TD, McMillin SL, Weyrauch LA, Stanley EC, Schmidt CA, Kilburg-Basnyat BB, Reece SW, Psaltis CE, Leinwand LA, Funai K, McClung JM, Gowdy KM, Witczak CA, Lowe DA, Neufer PD, Spangenburg EE. Estrogen receptor-α in female skeletal muscle is not required for regulation of muscle insulin sensitivity and mitochondrial regulation. Mol Metab 2020; 34:1-15. [PMID: 32180550 PMCID: PMC6994285 DOI: 10.1016/j.molmet.2019.12.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE Estrogen receptor-α (ERα) is a nuclear receptor family member thought to substantially contribute to the metabolic regulation of skeletal muscle. However, previous mouse models utilized to assess the necessity of ERα signaling in skeletal muscle were confounded by altered developmental programming and/or influenced by secondary effects, making it difficult to assign a causal role for ERα. The objective of this study was to determine the role of skeletal muscle ERα in regulating metabolism in the absence of confounding factors of development. METHODS A novel mouse model was developed allowing for induced deletion of ERα in adult female skeletal muscle (ERαKOism). ERαshRNA was also used to knockdown ERα (ERαKD) in human myotubes cultured from primary human skeletal muscle cells isolated from muscle biopsies from healthy and obese insulin-resistant women. RESULTS Twelve weeks of HFD exposure had no differential effects on body composition, VO2, VCO2, RER, energy expenditure, and activity counts across genotypes. Although ERαKOism mice exhibited greater glucose intolerance than wild-type (WT) mice after chronic HFD, ex vivo skeletal muscle glucose uptake was not impaired in the ERαKOism mice. Expression of pro-inflammatory genes was altered in the skeletal muscle of the ERαKOism, but the concentrations of these inflammatory markers in the systemic circulation were either lower or remained similar to the WT mice. Finally, skeletal muscle mitochondrial respiratory capacity, oxidative phosphorylation efficiency, and H2O2 emission potential was not affected in the ERαKOism mice. ERαKD in human skeletal muscle cells neither altered differentiation capacity nor caused severe deficits in mitochondrial respiratory capacity. CONCLUSIONS Collectively, these results suggest that ERα function is superfluous in protecting against HFD-induced skeletal muscle metabolic derangements after postnatal development is complete.
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Affiliation(s)
- Melissa R Iñigo
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA
| | - Adam J Amorese
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA
| | - Michael D Tarpey
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA
| | - Nicholas P Balestrieri
- East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA
| | - Keith G Jones
- East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA
| | - Daniel J Patteson
- East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA
| | - Kathryn C Jackson
- University of Maryland, School of Public Health, Department of Kinesiology, College Park, MD, USA
| | - Maria J Torres
- East Carolina University, Department of Kinesiology, Greenville, NC, USA
| | - Chien-Te Lin
- East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA
| | - Cody D Smith
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA
| | - Timothy D Heden
- East Carolina University, Department of Kinesiology, Greenville, NC, USA
| | - Shawna L McMillin
- East Carolina University, Department of Kinesiology, Greenville, NC, USA
| | - Luke A Weyrauch
- East Carolina University, Department of Kinesiology, Greenville, NC, USA
| | - Erin C Stanley
- East Carolina University, Department of Kinesiology, Greenville, NC, USA
| | - Cameron A Schmidt
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA
| | - Brita B Kilburg-Basnyat
- East Carolina University Brody School of Medicine, Department of Pharmacology and Toxicology, Greenville, NC, USA
| | - Sky W Reece
- East Carolina University Brody School of Medicine, Department of Pharmacology and Toxicology, Greenville, NC, USA
| | - Christine E Psaltis
- East Carolina University Brody School of Medicine, Department of Pharmacology and Toxicology, Greenville, NC, USA
| | - Leslie A Leinwand
- University of Colorado, Department of Molecular, Cellular, and Developmental Biology and BioFrontiers Institute, Boulder, CO, USA
| | - Katsuhiko Funai
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA; East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA; East Carolina University, Department of Kinesiology, Greenville, NC, USA
| | - Joseph M McClung
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA; East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA
| | - Kymberly M Gowdy
- East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA; East Carolina University Brody School of Medicine, Department of Pharmacology and Toxicology, Greenville, NC, USA
| | - Carol A Witczak
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA; East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA; East Carolina University, Department of Kinesiology, Greenville, NC, USA; East Carolina University, Department of Biochemistry and Molecular Biology, Greenville, NC, USA
| | - Dawn A Lowe
- University of Minnesota, Department of Rehabilitation Medicine, Division of Rehabilitation Science and Division of Physical Therapy, Minneapolis, MN, USA
| | - P Darrell Neufer
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA; East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA; East Carolina University, Department of Kinesiology, Greenville, NC, USA
| | - Espen E Spangenburg
- East Carolina University Brody School of Medicine, Department of Physiology, Greenville, NC, USA; East Carolina University, East Carolina Diabetes and Obesity Institute, Greenville, NC, USA; East Carolina University, Department of Kinesiology, Greenville, NC, USA.
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Pataky MW, Yu CS, Nie Y, Arias EB, Singh M, Mendias CL, Ploutz-Snyder RJ, Cartee GD. Skeletal muscle fiber type-selective effects of acute exercise on insulin-stimulated glucose uptake in insulin-resistant, high-fat-fed rats. Am J Physiol Endocrinol Metab 2019; 316:E695-E706. [PMID: 30753114 PMCID: PMC6580167 DOI: 10.1152/ajpendo.00482.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Insulin-stimulated glucose uptake (GU) by skeletal muscle is enhanced several hours after acute exercise in rats with normal or reduced insulin sensitivity. Skeletal muscle is composed of multiple fiber types, but exercise's effect on fiber type-specific insulin-stimulated GU in insulin-resistant muscle was previously unknown. Male rats were fed a high-fat diet (HFD; 2 wk) and were either sedentary (SED) or exercised (2-h exercise). Other, low-fat diet-fed (LFD) rats remained SED. Rats were studied immediately postexercise (IPEX) or 3 h postexercise (3hPEX). Epitrochlearis muscles from IPEX rats were incubated in 2-deoxy-[3H]glucose (2-[3H]DG) without insulin. Epitrochlearis muscles from 3hPEX rats were incubated with 2-[3H]DG ± 100 µU/ml insulin. After single fiber isolation, GU and fiber type were determined. Glycogen and lipid droplets (LDs) were assessed histochemically. GLUT4 abundance was determined by immunoblotting. In HFD-SED vs. LFD-SED rats, insulin-stimulated GU was decreased in type IIB, IIX, IIAX, and IIBX fibers. Insulin-independent GU IPEX was increased and glycogen content was decreased in all fiber types (types I, IIA, IIB, IIX, IIAX, and IIBX). Exercise by HFD-fed rats enhanced insulin-stimulated GU in all fiber types except type I. Single fiber analyses enabled discovery of striking fiber type-specific differences in HFD and exercise effects on insulin-stimulated GU. The fiber type-specific differences in insulin-stimulated GU postexercise in insulin-resistant muscle were not attributable to a lack of fiber recruitment, as indirectly evidenced by insulin-independent GU and glycogen IPEX, differences in multiple LD indexes, or altered GLUT4 abundance, implicating fiber type-selective differences in the cellular processes responsible for postexercise enhancement of insulin-mediated GLUT4 translocation.
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MESH Headings
- Animals
- Diet, High-Fat
- Glucose/metabolism
- Glucose Transporter Type 4/metabolism
- Glycogen/metabolism
- Insulin/pharmacology
- Insulin Resistance
- Lipid Droplets/metabolism
- Male
- Muscle Fibers, Fast-Twitch/drug effects
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Slow-Twitch/drug effects
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Physical Conditioning, Animal
- Rats
- Rats, Wistar
- Sedentary Behavior
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Affiliation(s)
- Mark W Pataky
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
| | - Carmen S Yu
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
| | - Yilin Nie
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
| | - Edward B Arias
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
| | - Manak Singh
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
| | - Christopher L Mendias
- Hospital for Special Surgery and Department of Physiology and Biophysics, Weill Cornell Medical College , New York, New York
| | | | - Gregory D Cartee
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
- Department of Molecular and Integrative Physiology, University of Michigan , Ann Arbor, Michigan
- Institute of Gerontology, University of Michigan , Ann Arbor, Michigan
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Tarpey MD, Amorese AJ, Balestrieri NP, Ryan TE, Schmidt CA, McClung JM, Spangenburg EE. Characterization and utilization of the flexor digitorum brevis for assessing skeletal muscle function. Skelet Muscle 2018; 8:14. [PMID: 29665848 PMCID: PMC5905177 DOI: 10.1186/s13395-018-0160-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 04/03/2018] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND The ability to assess skeletal muscle function and delineate regulatory mechanisms is essential to uncovering therapeutic approaches that preserve functional independence in a disease state. Skeletal muscle provides distinct experimental challenges due to inherent differences across muscle groups, including fiber type and size that may limit experimental approaches. The flexor digitorum brevis (FDB) possesses numerous properties that offer the investigator a high degree of experimental flexibility to address specific hypotheses. To date, surprisingly few studies have taken advantage of the FDB to investigate mechanisms regulating skeletal muscle function. The purpose of this study was to characterize and experimentally demonstrate the value of the FDB muscle for scientific investigations. METHODS First, we characterized the FDB phenotype and provide reference comparisons to skeletal muscles commonly used in the field. We developed approaches allowing for experimental assessment of force production, in vitro and in vivo microscopy, and mitochondrial respiration to demonstrate the versatility of the FDB. As proof-of principle, we performed experiments to alter force production or mitochondrial respiration to validate the flexibility the FDB affords the investigator. RESULTS The FDB is made up of small predominantly type IIa and IIx fibers that collectively produce less peak isometric force than the extensor digitorum longus (EDL) or soleus muscles, but demonstrates a greater fatigue resistance than the EDL. Unlike the other muscles, inherent properties of the FDB muscle make it amenable to multiple in vitro- and in vivo-based microscopy methods. Due to its anatomical location, the FDB can be used in cardiotoxin-induced muscle injury protocols and is amenable to electroporation of cDNA with a high degree of efficiency allowing for an effective means of genetic manipulation. Using a novel approach, we also demonstrate methods for assessing mitochondrial respiration in the FDB, which are comparable to the commonly used gastrocnemius muscle. As proof of principle, short-term overexpression of Pgc1α in the FDB increased mitochondrial respiration rates. CONCLUSION The results highlight the experimental flexibility afforded the investigator by using the FDB muscle to assess mechanisms that regulate skeletal muscle function.
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Affiliation(s)
- Michael D. Tarpey
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Adam J. Amorese
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Nicholas P. Balestrieri
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Terence E. Ryan
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Cameron A. Schmidt
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
| | - Joseph M. McClung
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834 USA
| | - Espen E. Spangenburg
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834 USA
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834 USA
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Zeng X, Chen S, Yang Y, Ke Z. Acylated and unacylated ghrelin inhibit atrophy in myotubes co-cultured with colon carcinoma cells. Oncotarget 2017; 8:72872-72885. [PMID: 29069832 PMCID: PMC5641175 DOI: 10.18632/oncotarget.20531] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 07/30/2017] [Indexed: 01/06/2023] Open
Abstract
Cancer cachexia is a result of increased protein degradation and decreased protein synthesis. The multifunctional circulating hormone ghrelin promotes synthesis and inhibits degradation of muscle protein, but its mechanism of action is not fully understood. Here, we investigated whether co-culturing C2C12 myotubes with CT26 colon carcinoma cells induces myotube atrophy, and whether acylated ghrelin (AG) and unacylated ghrelin (UnAG) had anti-atrophic effects. We found that co-culture induced myotube atrophy and increased tumor necrosis factor-alpha (TNF-α) and myostatin concentrations in the culture medium. Moreover, co-culture down-regulated myogenin and MyoD expression, inhibited the Akt signaling, up-regulated ubiquitin E3 ligase expression, and activated the calpain system and autophagy in myotubes. Both AG and UnAG inhibited these changes. Our study describes a novel in vitro model that can be employed to investigate cancer cachexia, and our findings suggest a possible use for AG and UnAG in treating cancer cachexia.
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Affiliation(s)
- Xianliang Zeng
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, China
| | - Sizeng Chen
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, China
| | - Yang Yang
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, China
| | - Zhao Ke
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, China
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5
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Varlamov O. Western-style diet, sex steroids and metabolism. Biochim Biophys Acta Mol Basis Dis 2016; 1863:1147-1155. [PMID: 27264336 DOI: 10.1016/j.bbadis.2016.05.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 05/27/2016] [Accepted: 05/28/2016] [Indexed: 12/14/2022]
Abstract
The evolutionary transition from hunting to farming was associated with introduction of carbohydrate-rich diets. Today, the increased consumption of simple sugars and high-fat food brought about by Western-style diet and physical inactivity are leading causes of the growing obesity epidemic in the Western society. The extension of human lifespan far beyond reproductive age increased the burden of metabolic disorders associated with overnutrition and age-related hypogonadism. Sex steroids are essential regulators of both reproductive function and energy metabolism, whereas their imbalance causes infertility, obesity, glucose intolerance, dyslipidemia, and increased appetite. Clinical and translational studies suggest that dietary restriction and weight control can improve metabolic and reproductive outcomes of sex hormone-related pathologies, including testosterone deficiency in men and natural menopause and hyperandrogenemia in women. Minimizing metabolic and reproductive decline through rationally designed diet and exercise can help extend human reproductive age and promote healthy aging. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.
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Affiliation(s)
- Oleg Varlamov
- Division of Diabetes, Obesity, and Metabolism, Oregon National Primate Research Center, Beaverton, OR 97006, United States.
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Jackson KC, Gidlund EK, Norrbom J, Valencia AP, Thomson DM, Schuh RA, Neufer PD, Spangenburg EE. BRCA1 is a novel regulator of metabolic function in skeletal muscle. J Lipid Res 2014; 55:668-80. [PMID: 24565757 PMCID: PMC3966701 DOI: 10.1194/jlr.m043851] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Revised: 01/28/2014] [Indexed: 12/19/2022] Open
Abstract
Breast cancer type 1 (BRCA1) susceptibility protein is expressed across multiple tissues including skeletal muscle. The overall objective of this investigation was to define a functional role for BRCA1 in skeletal muscle using a translational approach. For the first time in both mice and humans, we identified the presence of multiple isoforms of BRCA1 in skeletal muscle. In response to an acute bout of exercise, we found increases in the interaction between the native forms of BRCA1 and the phosphorylated form of acetyl-CoA carboxylase. Decreasing BRCA1 content using a shRNA approach in cultured primary human myotubes resulted in decreased oxygen consumption by the mitochondria and increased reactive oxygen species production. The decreased BRCA1 content also resulted in increased storage of intracellular lipid and reduced insulin signaling. These results indicate that BRCA1 plays a critical role in the regulation of metabolic function in skeletal muscle. Collectively, these data reveal BRCA1 as a novel target to consider in our understanding of metabolic function and risk for development of metabolic-based diseases.
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Affiliation(s)
- Kathryn C. Jackson
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, MD
| | - Eva-Karin Gidlund
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Jessica Norrbom
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Ana P. Valencia
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, MD
| | - David M. Thomson
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT
| | - Rosemary A. Schuh
- Research Service, Maryland Veteran Affairs Health Care System, Baltimore, MD
- Department of Neurology, School of Medicine, University of Maryland, Baltimore, MD
| | - P. Darrell Neufer
- Departments of Physiology and Kinesiology, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC
| | - Espen E. Spangenburg
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, MD
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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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