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Fachada V, Silvennoinen M, Sahinaho UM, Rahkila P, Kivelä R, Hulmi JJ, Kujala U, Kainulainen H. Effects of Long-Term Physical Activity and BCAA Availability on the Subcellular Associations between Intramyocellular Lipids, Perilipins and PGC-1 α. Int J Mol Sci 2023; 24:ijms24054282. [PMID: 36901715 PMCID: PMC10002284 DOI: 10.3390/ijms24054282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 02/09/2023] [Indexed: 02/24/2023] Open
Abstract
Cellular skeletal muscle lipid metabolism is of paramount importance for metabolic health, specifically through its connection to branched-chain amino acids (BCAA) metabolism and through its modulation by exercise. In this study, we aimed at better understanding intramyocellular lipids (IMCL) and their related key proteins in response to physical activity and BCAA deprivation. By means of confocal microscopy, we examined IMCL and the lipid droplet coating proteins PLIN2 and PLIN5 in human twin pairs discordant for physical activity. Additionally, in order to study IMCLs, PLINs and their association to peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) in cytosolic and nuclear pools, we mimicked exercise-induced contractions in C2C12 myotubes by electrical pulse stimulation (EPS), with or without BCAA deprivation. The life-long physically active twins displayed an increased IMCL signal in type I fibers when compared to their inactive twin pair. Moreover, the inactive twins showed a decreased association between PLIN2 and IMCL. Similarly, in the C2C12 cell line, PLIN2 dissociated from IMCL when myotubes were deprived of BCAA, especially when contracting. In addition, in myotubes, EPS led to an increase in nuclear PLIN5 signal and its associations with IMCL and PGC-1α. This study demonstrates how physical activity and BCAA availability affects IMCL and their associated proteins, providing further and novel evidence for the link between the BCAA, energy and lipid metabolisms.
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Fachada V, Rahkila P, Fachada N, Turpeinen T, Kujala UM, Kainulainen H. Enlarged PLIN5-uncoated lipid droplets in inner regions of skeletal muscle type II fibers associate with type 2 diabetes. Acta Histochem 2022; 124:151869. [PMID: 35220055 DOI: 10.1016/j.acthis.2022.151869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 02/03/2022] [Accepted: 02/12/2022] [Indexed: 01/02/2023]
Abstract
Skeletal muscle physiology remains of paramount importance in understanding insulin resistance. Due to its high lipid turnover rates, regulation of intramyocellular lipid droplets (LDs) is a key factor. Perilipin 5 (PLIN5) is one of the most critical agents in such regulation, being often referred as a protector against lipotoxicity and consequent skeletal muscle insulin resistance. We examined area fraction, size, subcellular localization and PLIN5 association of LDs in two fiber types of type 2 diabetic (T2D), obese (OB) and healthy (HC) individuals by means of fluorescence microscopy and image analysis. We found that T2D type II fibers have a significant sub-population of large and internalized LDs, uncoated by PLIN5. Based on this novel result, additional hypotheses for the pathophysiology of skeletal muscle insulin resistance are formulated, together with future research directions.
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Affiliation(s)
- Vasco Fachada
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, University of Jyvaskyla, Rautpohjankatu 8, Jyvaskyla 40014, Finland.
| | - Paavo Rahkila
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, University of Jyvaskyla, Rautpohjankatu 8, Jyvaskyla 40014, Finland
| | - Nuno Fachada
- Lusofona University, COPELABS, Lisboa 1749-024, Portugal
| | - Tuomas Turpeinen
- Department of Physics, University of Jyvaskyla, Jyvaskyla 40014, Finland
| | - Urho M Kujala
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, University of Jyvaskyla, Rautpohjankatu 8, Jyvaskyla 40014, Finland
| | - Heikki Kainulainen
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, University of Jyvaskyla, Rautpohjankatu 8, Jyvaskyla 40014, Finland
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3
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Barrett JS, Whytock KL, Strauss JA, Wagenmakers AJM, Shepherd SO. High intramuscular triglyceride turnover rates and the link to insulin sensitivity: influence of obesity, type 2 diabetes and physical activity. Appl Physiol Nutr Metab 2022; 47:343-356. [PMID: 35061523 DOI: 10.1139/apnm-2021-0631] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Large intramuscular triglyceride (IMTG) stores in sedentary, obese individuals have been linked to insulin resistance, yet well-trained athletes exhibit high IMTG levels whilst maintaining insulin sensitivity. Contrary to previous assumptions, it is now known that IMTG content per se does not result in insulin resistance. Rather, insulin resistance is caused, at least in part, by the presence of high concentrations of harmful lipid metabolites, such as diacylglycerols and ceramides in muscle. Several mechanistic differences between obese sedentary individuals and their highly trained counterparts have been identified, which determine the differential capacity for IMTG synthesis and breakdown in these populations. In this review, we first describe the most up-to-date mechanisms by which a low IMTG turnover rate (both breakdown and synthesis) leads to the accumulation of lipid metabolites and results in skeletal muscle insulin resistance. We then explore current and potential exercise and nutritional strategies that target IMTG turnover in sedentary obese individuals, to improve insulin sensitivity. Overall, improving IMTG turnover should be an important component of successful interventions that aim to prevent the development of insulin resistance in the ever-expanding sedentary, overweight and obese populations. Novelty: A description of the most up-to-date mechanisms regulating turnover of the IMTG pool. An exploration of current and potential exercise/nutritional strategies to target and enhance IMTG turnover in obese individuals. Overall, highlights the importance of improving IMTG turnover to prevent the development of insulin resistance.
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Affiliation(s)
- J S Barrett
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - K L Whytock
- Translational Research Institute, AdventHealth, Orlando, FL 32804, USA
| | - J A Strauss
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - A J M Wagenmakers
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - S O Shepherd
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, UK
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4
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Mengeste AM, Rustan AC, Lund J. Skeletal muscle energy metabolism in obesity. Obesity (Silver Spring) 2021; 29:1582-1595. [PMID: 34464025 DOI: 10.1002/oby.23227] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 03/29/2021] [Accepted: 04/06/2021] [Indexed: 01/22/2023]
Abstract
Comparing energy metabolism in human skeletal muscle and primary skeletal muscle cells in obesity, while focusing on glucose and fatty acid metabolism, shows many common changes. Insulin-mediated glucose uptake in skeletal muscle and primary myotubes is decreased by obesity, whereas differences in basal glucose metabolism are inconsistent among studies. With respect to fatty acid metabolism, there is an increased uptake and storage of fatty acids and a reduced complete lipolysis, suggesting alterations in lipid turnover. In addition, fatty acid oxidation is decreased, probably at the level of complete oxidation, as β -oxidation may be enhanced in obesity, which indicates mitochondrial dysfunction. Metabolic changes in skeletal muscle with obesity promote metabolic inflexibility, ectopic lipid accumulation, and formation of toxic lipid intermediates. Skeletal muscle also acts as an endocrine organ, secreting myokines that participate in interorgan cross talk. This review highlights interventions and some possible targets for treatment through action on skeletal muscle energy metabolism. Effects of exercise in vivo on obesity have been compared with simulation of endurance exercise in vitro on myotubes (electrical pulse stimulation). Possible pharmaceutical targets, including signaling pathways and drug candidates that could modify lipid storage and turnover or increase mitochondrial function or cellular energy expenditure through adaptive thermogenic mechanisms, are discussed.
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Affiliation(s)
- Abel M Mengeste
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Arild C Rustan
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Jenny Lund
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
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5
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Zhao Y, Albrecht E, Li Z, Schregel J, Sciascia QL, Metges CC, Maak S. Distinct Roles of Perilipins in the Intramuscular Deposition of Lipids in Glutamine-Supplemented, Low-, and Normal-Birth-Weight Piglets. Front Vet Sci 2021; 8:633898. [PMID: 34235195 PMCID: PMC8257002 DOI: 10.3389/fvets.2021.633898] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 05/10/2021] [Indexed: 11/13/2022] Open
Abstract
Piglets with low birth weight (LBW) usually have reduced muscle mass and increased lipid deposition compared with their normal-birth-weight (NBW) littermates. Supplementation of piglets with amino acids during the first days of life may improve muscle growth and simultaneously alter the intramuscular lipid deposition. The aim of the current study was to investigate the influence of glutamine (Gln) supplementation during the early suckling period on lipid deposition in the longissimus muscle (MLD) and the role of different perilipin (PLIN) family members in this process. Four groups were generated consisting of 72 male LBW piglets and 72 NBW littermates. Piglets were supplemented with either 1 g Gln/kg body weight or an isonitrogenous amount of alanine (Ala) between days post natum (dpn) 1 and 12. Twelve piglets per group were slaughtered at 5, 12, and 26 dpn, and muscle tissue was collected. Perilipins were localized by immunohistochemistry in muscle sections. The mRNA and protein abundances of PLIN family members and related lipases were quantified by quantitative RT-PCR (qPCR) and western blots, respectively. While PLIN1 was localized around lipid droplets in mature and developing adipocytes, PLIN2 was localized at intramyocellular lipid droplets, PLIN3 and 4 at cell membranes of muscle fibers and adipocytes, and PLIN5 in the cytoplasm of undefined cells. The western blot results indicated higher protein abundances of PLIN2, 3, 4, and 5 in LBW piglets (p < 0.05) at 5 dpn compared with their NBW littermates independent of supplementation, while not directly reflecting the mRNA expression levels. The mRNA abundance of PLIN2 was lower while PLIN4 was higher in piglets at 26 dpn in comparison with piglets at 5 dpn (p < 0.01). Relative mRNA expression of LPL and CGI-58 was lowest in piglets at 5 dpn (p < 0.001). However, ATGL mRNA was not influenced by birth weight or supplementation, but the Spearman correlation coefficient analysis revealed close correlations with PLIN2, 4, and 5 mRNA at 5 and 26 dpn (r > 0.5, p < 0.001). The results indicated the importance of birth weight and age for intramuscular lipid deposition and different roles of PLIN family members in this process, but no clear modulating effect of Gln supplementation.
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Affiliation(s)
- Yaolu Zhao
- Institute of Muscle Biology and Growth, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Elke Albrecht
- Institute of Muscle Biology and Growth, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Zeyang Li
- Institute of Nutritional Physiology "Oskar Kellner", Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Johannes Schregel
- Institute of Nutritional Physiology "Oskar Kellner", Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Quentin L Sciascia
- Institute of Nutritional Physiology "Oskar Kellner", Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Cornelia C Metges
- Institute of Nutritional Physiology "Oskar Kellner", Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Steffen Maak
- Institute of Muscle Biology and Growth, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
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6
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Tobias IS, Galpin AJ. Moving human muscle physiology research forward: an evaluation of fiber type-specific protein research methodologies. Am J Physiol Cell Physiol 2020; 319:C858-C876. [DOI: 10.1152/ajpcell.00107.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Human skeletal muscle is a heterogeneous tissue composed of multiple fiber types that express unique contractile and metabolic properties. While analysis of mixed fiber samples predominates and holds value, increasing attention has been directed toward studying proteins segregated by fiber type, a methodological distinction termed “fiber type-specific.” Fiber type-specific protein studies have the advantage of uncovering key molecular effects that are often missed in mixed fiber homogenate studies but also require greater time and resource-intensive methods, particularly when applied to human muscle. This review summarizes and compares current methods used for fiber type-specific protein analysis, highlighting their advantages and disadvantages for human muscle studies, in addition to recent advances in these techniques. These methods can be grouped into three categories based on the initial processing of the tissue: 1) muscle-specific fiber homogenates, 2) cross sections of fiber bundles, and 3) isolated single fibers, with various subtechniques for performing fiber type identification and protein quantification. The relative implementation for each unique methodological approach is analyzed from 83 fiber type-specific studies of proteins in live human muscle found in the literature to date. These studies have investigated several proteins involved in a wide range of cellular functions that are important to muscle tissue. The second half of this review summarizes key findings from this ensemble of fiber type-specific human protein studies. We highlight examples of where this analytical approach has helped to improve understanding of important physiological topics such as insulin sensitivity, muscle hypertrophy, muscle fatigue, and adaptation to different exercise programs.
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Affiliation(s)
- Irene S. Tobias
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
| | - Andrew J. Galpin
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California
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7
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Jevons EFP, Gejl KD, Strauss JA, Ørtenblad N, Shepherd SO. Skeletal muscle lipid droplets are resynthesized before being coated with perilipin proteins following prolonged exercise in elite male triathletes. Am J Physiol Endocrinol Metab 2020; 318:E357-E370. [PMID: 31935113 DOI: 10.1152/ajpendo.00399.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Intramuscular triglycerides (IMTG) are a key substrate during prolonged exercise, but little is known about the rate of IMTG resynthesis in the postexercise period. We investigated the hypothesis that the distribution of the lipid droplet (LD)-associated perilipin (PLIN) proteins is linked to IMTG storage following exercise. Fourteen elite male triathletes (27 ± 1 yr, 66.5 ± 1.3 mL·kg-1·min-1) completed 4 h of moderate-intensity cycling. During the first 4 h of recovery, subjects received either carbohydrate or H2O, after which both groups received carbohydrate. Muscle biopsies collected pre- and postexercise and 4 and 24 h postexercise were analyzed using confocal immunofluorescence microscopy for fiber type-specific IMTG content and PLIN distribution with LDs. Exercise reduced IMTG content in type I fibers (-53%, P = 0.002), with no change in type IIa fibers. During the first 4 h of recovery, IMTG content increased in type I fibers (P = 0.014), but was not increased more after 24 h, where it was similar to baseline levels in both conditions. During recovery the number of LDs labeled with PLIN2 (70%), PLIN3 (63%), and PLIN5 (62%; all P < 0.05) all increased in type I fibers. Importantly, the increase in LDs labeled with PLIN proteins only occurred at 24 h postexercise. In conclusion, IMTG resynthesis occurs rapidly in type I fibers following prolonged exercise in highly trained individuals. Furthermore, increases in IMTG content following exercise preceded an increase in the number of LDs labeled with PLIN proteins. These data, therefore, suggest that the PLIN proteins do not play a key role in postexercise IMTG resynthesis.
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Affiliation(s)
- Emily F P Jevons
- Research Institute of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Kasper D Gejl
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Juliette A Strauss
- Research Institute of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Sam O Shepherd
- Research Institute of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
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8
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Shaw CS, Swinton C, Morales-Scholz MG, McRae N, Erftemeyer T, Aldous A, Murphy RM, Howlett KF. Impact of exercise training status on the fiber type-specific abundance of proteins regulating intramuscular lipid metabolism. J Appl Physiol (1985) 2020; 128:379-389. [PMID: 31917629 DOI: 10.1152/japplphysiol.00797.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Endurance training enhances the capacity for fat oxidation during exercise due to increased utilization of intramuscular lipid (IMCL). This study quantitatively investigated the impact of exercise training status on muscle fiber type-specific abundance of regulatory proteins involved in IMCL utilization. Endurance-trained [n = 7 subjects, peak oxygen consumption (V̇o2peak) 62.6 ± 4.1 (SD) mL·min-1·kg-1] and non-endurance-trained (n = 8 subjects, V̇o2peak 44.9 ± 5.3 mL·min-1·kg-1) young men completed an incremental exercise test to determine maximal fat oxidation (MFO) and maximal oxygen uptake. Fiber type-specific IMCL content and protein abundance were assessed with immunofluorescence microscopy and immunoblot analysis of pooled single muscle fibers and whole muscle. Endurance-trained individuals displayed a higher MFO rate (0.45 ± 0.15 vs. 0.19 ± 0.07 g/min, P < 0.05), a greater proportion of type I muscle fibers, and higher IMCL content compared with untrained individuals (P < 0.05). Adipose triglyceride lipase, hormone-sensitive lipase, perilipin 2, perilipin 5, and hydroxyacyl-coenzyme A dehydrogenase abundances were ~2-3-fold higher in type I muscle fibers compared with type IIa fibers (P < 0.05). Correspondingly, these lipid proteins and oxidative enzymes were higher in endurance-trained individuals when assessed in whole muscle. MFO rate was strongly related to the proportion of type I fibers (R = 0.81, P < 0.01). The abundance of proteins involved in the regulation of IMCL storage and oxidation is highly muscle fiber type specific. The increased capacity for fat oxidation in endurance-trained individuals corresponded with increased IMCL content and elevated abundance of lipolytic and oxidative enzymes in combination with a greater proportion of type I muscle fibers.NEW & NOTEWORTHY We have utilized contemporary techniques to compare the fiber type-specific characteristics of skeletal muscle from endurance-trained athletes and untrained individuals. We show that type I muscle fibers have a coordinated upregulation of proteins controlling intramuscular lipid storage, mobilization, and oxidation. Furthermore, the enhanced capacity for intramuscular lipid storage and utilization in endurance-trained individuals is related to the increased expression of lipid regulatory proteins combined with a greater proportion of type I muscle fibers.
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Affiliation(s)
- C S Shaw
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - C Swinton
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - M G Morales-Scholz
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - N McRae
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - T Erftemeyer
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - A Aldous
- Olympic Park Sports Medicine Centre, Melbourne, Victoria, Australia
| | - R M Murphy
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - K F Howlett
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
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9
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10
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Redwan EM, Alkarim SA, El-Hanafy AA, Saad YM, Almehdar HA, Uversky VN. Disorder in milk proteins: adipophilin and TIP47, important constituents of the milk fat globule membrane. J Biomol Struct Dyn 2019; 38:1214-1229. [PMID: 30896308 DOI: 10.1080/07391102.2019.1592027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Milk fat globules (MFGs), which are secreted by the epithelial cells of the lactating mammary glands, account for the most of the nutritional value of milk. They are enveloped by the milk fat globule membrane (MFGM), a complex structure consisting of three phospholipid membrane monolayers and containing various lipids. Depending on the origin of milk, specific proteins accounts for 5-70% of the MFGM mass. Proteome of MFGMs includes hundreds of proteins, with nine major components being adipophilin, butyrophilin, cluster of differentiation 36, fatty acid binding protein, lactadherin, mucin 1, mucin 15, tail-interacting protein 47 (TIP47), and xanthine oxidoreductase. Two of the MFGM components, adipophilin and TIP47, belong to the five-member perilipin family of lipid droplet proteins. Adipophilin is involved in the formation of cytoplasmic lipid droplets and secretion of MFGs. This protein is also related to the formation of other lipid droplets that exist in most cell types, playing an important role in the transport of lipids from ER to the surface of lipid droplets. TIP47 acts as a cytoplasmic sorting factor for mannose 6-phosphate receptors and is recruited to the MFGM. Therefore, both adipophilin and TIP47 are moonlighting proteins, each possessing several unrelated functions. This review focuses on the main functions and specific structural features of adipophilin and TIP47, analyzes similarities and differences of these proteins among different species, and describes these proteins in the context of other members of the perilipin family.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Elrashdy M Redwan
- Biological Sciences Department, Faculty of Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.,Protein Research Department, Therapeutic and Protective Proteins Laboratory, Genetic Engineering and Biotechnology Research Institute, City for Scientific Research and Technology Applications, Alexandria, Egypt
| | - Saleh A Alkarim
- Biological Sciences Department, Faculty of Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Amr A El-Hanafy
- Biological Sciences Department, Faculty of Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Nucleic Acid Research, Genetic Engineering and Biotechnology Research Institute, City for Scientific Research & Technology Applications, Borg EL-Arab, Alexandria, Egypt
| | - Yasser M Saad
- Biological Sciences Department, Faculty of Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.,Genetics Laboratory, National Institute of Oceanography and Fisheries, Cairo, Egypt
| | - Hussein A Almehdar
- Biological Sciences Department, Faculty of Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Vladimir N Uversky
- Biological Sciences Department, Faculty of Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.,Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Russia Moscow Region.,Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
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11
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Yue B, Wu J, Shao S, Zhang C, Fang X, Bai Y, Qi X, Chen H. Polymorphism in PLIN2 gene and its association with growth traits in Chinese native cattle. Anim Biotechnol 2019; 31:142-147. [PMID: 30717637 DOI: 10.1080/10495398.2018.1555166] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Perilipin 2 (PLIN2) is a cytosolic protein that regulates intracellular lipid storage and mobilization. However, research reports of the relationship between PLIN2 gene and growth traits in cattle are rare. Here, five novel single nucleotide polymorphisms (SNPs)(g.3036G > C, g.3964C > T, g.6458G > T, g.6555C > T and g.8231G > A)were identified within the bovine PLIN2 gene using DNA sequencing and PCR-SSCP methods in 820 individuals from four Chinese indigenous bovine breeds. Overall, five common haplotypes were identified based on the 5 SNPs, with the most common haplotypes (GCGCG) occurring at a frequency of 69.0%. In addition, The 5 novel SNPs were associated with growth traits at 6, 12, 18 and 24 months in Nanyang population, and significant associations were found in body weight and heart girth. These results suggest that PLIN2 possibly is a strong candidate gene marker for body weight in cattle breeding program.
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Affiliation(s)
- Binglin Yue
- Institute of Cellular and Molecular Biology, College of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, P. R. China
| | - Jiyao Wu
- Institute of Cellular and Molecular Biology, College of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, P. R. China
| | - Simin Shao
- Institute of Cellular and Molecular Biology, College of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, P. R. China
| | - Chunlei Zhang
- Institute of Cellular and Molecular Biology, College of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, P. R. China
| | - Xingtang Fang
- Institute of Cellular and Molecular Biology, College of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, P. R. China
| | - Yueyu Bai
- Animal Health Supervision in Henan Province, Zhengzhou, Henan, P. R. China
| | - Xingshan Qi
- Bureau of Animal Husbandry of Biyang County, Biyang, Henan, P. R. China
| | - Hong Chen
- Institute of Cellular and Molecular Biology, College of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, P. R. China
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12
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Sharma A, Jha AK, Mishra S, Jain A, Chauhan BS, Kathuria M, Rawat KS, Gupta NM, Tripathi R, Mitra K, Sachdev M, Bhatt MLB, Goel A. Imaging and Quantitative Detection of Lipid Droplets by Yellow Fluorescent Probes in Liver Sections of Plasmodium Infected Mice and Third Stage Human Cervical Cancer Tissues. Bioconjug Chem 2018; 29:3606-3613. [DOI: 10.1021/acs.bioconjchem.8b00552] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Ashutosh Sharma
- Fluorescent Chemistry Lab, Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Ajay K. Jha
- Fluorescent Chemistry Lab, Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Shachi Mishra
- Fluorescent Chemistry Lab, Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Ankita Jain
- Endocrinology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Bhavana S. Chauhan
- Parasitology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Manoj Kathuria
- Electron Microscopy Unit, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Kundan S. Rawat
- Fluorescent Chemistry Lab, Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
- Academy of Scientific
and Innovative Research, Ghaziabad 201 002, India
| | - Neeraj M. Gupta
- Fluorescent Chemistry Lab, Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Renu Tripathi
- Parasitology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Kalyan Mitra
- Electron Microscopy Unit, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Monika Sachdev
- Endocrinology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Madan L. B. Bhatt
- Department of Radiotherapy, King George’s Medical University, Lucknow 226003, India
| | - Atul Goel
- Fluorescent Chemistry Lab, Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
- Academy of Scientific
and Innovative Research, Ghaziabad 201 002, India
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13
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Hiramoto S, Yahata N, Saitoh K, Yoshimura T, Wang Y, Taniyama S, Nikawa T, Tachibana K, Hirasaka K. Dietary supplementation with alkylresorcinols prevents muscle atrophy through a shift of energy supply. J Nutr Biochem 2018; 61:147-154. [PMID: 30236871 DOI: 10.1016/j.jnutbio.2018.08.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 08/03/2018] [Accepted: 08/16/2018] [Indexed: 12/11/2022]
Abstract
It has been reported that phytoextracts that contain alkylresorcinols (ARs) protect against severe myofibrillar degeneration found in isoproterenol-induced myocardial infarction. In this study, we examined the effect of dietary ARs derived from wheat bran extracts on muscle atrophy in denervated mice. The mice were divided into the following four groups: (1) sham-operated (control) mice fed with normal diet (S-ND), (2) denervated mice fed with normal diet (D-ND), (3) control mice fed with ARs-supplemented diet (S-AR) and (4) denervated mice fed with ARs-supplemented diet (D-AR). The intake of ARs prevented the denervation-induced reduction of the weight of the hind limb muscles and the myofiber size. However, the expression of ubiquitin ligases and autophagy-related genes, which is associated with muscle proteolysis, was slightly higher in D-AR than in D-ND. Moreover, the abundance of the autophagy marker p62 was significantly higher in D-AR than in D-ND. Muscle atrophy has been known to be associated with a disturbed energy metabolism. The expression of pyruvate dehydrogenase kinase 4 (PDK4), which is related to fatty acid metabolism, was decreased in D-ND as compared with that in S-ND. In contrast, dietary supplementation with ARs inhibited the decrease of PDK4 expression caused by denervation. Furthermore, the abnormal expression pattern of genes related to the abundance of lipid droplets-coated proteins that was induced by denervation was improved by ARs. These results raise the possibility that dietary supplementation with ARs modifies the disruption of fatty acid metabolism induced by lipid autophagy, resulting in the prevention of muscle atrophy.
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Affiliation(s)
- Shigeru Hiramoto
- Healthcare Research Center, Nisshin Pharma Inc., Saitama, Japan 3568511
| | - Nobuhiro Yahata
- Healthcare Research Center, Nisshin Pharma Inc., Saitama, Japan 3568511
| | - Kanae Saitoh
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan 8528521
| | - Tomohiro Yoshimura
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan 8528521
| | - Yao Wang
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan 8528521
| | - Shigeto Taniyama
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan 8528521
| | - Takeshi Nikawa
- Department of Nutritional Physiology, Institute of Medical Nutrition, Tokushima University Medical School, Tokushima, Japan 7708503
| | - Katsuyasu Tachibana
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan 8528521
| | - Katsuya Hirasaka
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan 8528521; Organization for Marine Science and Technology, Nagasaki University, Nagasaki, Japan 8528521.
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14
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An aPPARent Functional Consequence in Skeletal Muscle Physiology via Peroxisome Proliferator-Activated Receptors. Int J Mol Sci 2018; 19:ijms19051425. [PMID: 29747466 PMCID: PMC5983589 DOI: 10.3390/ijms19051425] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/05/2018] [Accepted: 05/08/2018] [Indexed: 12/12/2022] Open
Abstract
Skeletal muscle comprises 30–40% of the total body mass and plays a central role in energy homeostasis in the body. The deregulation of energy homeostasis is a common underlying characteristic of metabolic syndrome. Over the past decades, peroxisome proliferator-activated receptors (PPARs) have been shown to play critical regulatory roles in skeletal muscle. The three family members of PPAR have overlapping roles that contribute to the myriad of processes in skeletal muscle. This review aims to provide an overview of the functions of different PPAR members in energy homeostasis as well as during skeletal muscle metabolic disorders, with a particular focus on human and relevant mouse model studies.
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15
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Nielsen J, Christensen AE, Nellemann B, Christensen B. Lipid droplet size and location in human skeletal muscle fibers are associated with insulin sensitivity. Am J Physiol Endocrinol Metab 2017; 313:E721-E730. [PMID: 28743757 DOI: 10.1152/ajpendo.00062.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 06/28/2017] [Accepted: 07/18/2017] [Indexed: 11/22/2022]
Abstract
In skeletal muscle, an accumulation of lipid droplets (LDs) in the subsarcolemmal space is associated with insulin resistance, but the underlying mechanism is not clear. We aimed to investigate how the size, number, and location of LDs are associated with insulin sensitivity and muscle fiber types and are regulated by aerobic training and treatment with an erythropoiesis-stimulating agent (ESA) in healthy young untrained men. LD analyses were performed by quantitative transmission electron microscopy, and insulin sensitivity was assessed by a hyperinsulinemic-euglycemic clamp. At baseline, we found that only the diameter (and not the number) of individual subsarcolemmal LDs was negatively associated with insulin sensitivity (R2 = 0.20, P = 0.03, n = 29). Despite 34% (P = 0.004) fewer LDs, the diameter of individual subsarcolemmal LDs was 20% (P = 0.0004) larger in type 2 fibers than in type 1 fibers. Furthermore, aerobic training decreased the size of subsarcolemmal LDs in the type 2 fibers, and ESA treatment lowered the number of both intermyofibrillar and subsarcolemmal LDs in the type 1 fibers. In conclusion, the size of individual subsarcolemmal LDs may be involved in the mechanism by which LDs are associated with insulin resistance in skeletal muscle.
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Affiliation(s)
- Joachim Nielsen
- Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Odense M, Denmark;
- Department of Pathology, SDU Muscle Research Cluster (SMRC), Odense University Hospital, Odense C, Denmark; and
| | - Anders E Christensen
- Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Odense M, Denmark
| | - Birgitte Nellemann
- Department of Endocrinology and Internal Medicine, NBG/THG, Aarhus University Hospital, Aarhus, Denmark
| | - Britt Christensen
- Department of Endocrinology and Internal Medicine, NBG/THG, Aarhus University Hospital, Aarhus, Denmark
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16
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Feng YZ, Lund J, Li Y, Knabenes IK, Bakke SS, Kase ET, Lee YK, Kimmel AR, Thoresen GH, Rustan AC, Dalen KT. Loss of perilipin 2 in cultured myotubes enhances lipolysis and redirects the metabolic energy balance from glucose oxidation towards fatty acid oxidation. J Lipid Res 2017; 58:2147-2161. [PMID: 28822960 DOI: 10.1194/jlr.m079764] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Indexed: 02/07/2023] Open
Abstract
Lipid droplet (LD) coating proteins are essential for the formation and stability of intracellular LDs. Plin2 is an abundant LD coating protein in skeletal muscle, but its importance for muscle function is unclear. We show that myotubes established from Plin2-/- mice contain reduced content of LDs and accumulate less oleic acid (OA) in triacylglycerol (TAG) due to elevated LD hydrolysis in comparison with Plin2+/+ myotubes. The reduced ability to store TAG in LDs in Plin2-/- myotubes is accompanied by a shift in energy metabolism. Plin2-/- myotubes are characterized by increased oxidation of OA, lower glycogen synthesis, and reduced glucose oxidation in comparison with Plin2+/+ myotubes, perhaps reflecting competition between FAs and glucose as part of the Randle cycle. In accord with these metabolic changes, Plin2-/- myotubes have elevated expression of Ppara and Ppargc1a, transcription factors that stimulate expression of genes important for FA oxidation, whereas genes involved in glucose uptake and oxidation are suppressed. Loss of Plin2 had no impact on insulin-stimulated Akt phosphorylation. Our results suggest that Plin2 is essential for protecting the pool of skeletal muscle LDs to avoid an uncontrolled hydrolysis of stored TAG and to balance skeletal muscle energy metabolism.
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Affiliation(s)
- Yuan Z Feng
- Department of Pharmaceutical Biosciences, School of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Jenny Lund
- Department of Pharmaceutical Biosciences, School of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Yuchuan Li
- Department of Nutrition, University of Oslo, Oslo, Norway
| | - Irlin K Knabenes
- Department of Pharmaceutical Biosciences, School of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Siril S Bakke
- Department of Pharmaceutical Biosciences, School of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Eili T Kase
- Department of Pharmaceutical Biosciences, School of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Yun K Lee
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Alan R Kimmel
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - G Hege Thoresen
- Department of Pharmaceutical Biosciences, School of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway.,Department of Pharmacology, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Arild Christian Rustan
- Department of Pharmaceutical Biosciences, School of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Knut Tomas Dalen
- Department of Nutrition, University of Oslo, Oslo, Norway .,The Norwegian Transgenic Center, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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17
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Shepherd SO, Strauss JA, Wang Q, Dube JJ, Goodpaster B, Mashek DG, Chow LS. Training alters the distribution of perilipin proteins in muscle following acute free fatty acid exposure. J Physiol 2017; 595:5587-5601. [PMID: 28560826 PMCID: PMC5556155 DOI: 10.1113/jp274374] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 05/17/2017] [Indexed: 01/02/2023] Open
Abstract
KEY POINTS The lipid droplet (LD)-associated perilipin (PLIN) proteins promote intramuscular triglyceride (IMTG) storage, although whether the abundance and association of the PLIN proteins with LDs is related to the diverse lipid storage in muscle between trained and sedentary individuals is unknown. We show that lipid infusion augments IMTG content in type I fibres of both trained and sedentary individuals. Most importantly, despite there being no change in PLIN protein content, lipid infusion did increase the number of LDs connected with PLIN proteins in trained individuals only. We conclude that trained individuals are able to redistribute the pre-existing pool of PLIN proteins to an expanded LD pool during lipid infusion and, via this adaptation, may support the storage of fatty acids in IMTG. ABSTRACT Because the lipid droplet (LD)-associated perilipin (PLIN) proteins promote intramuscular triglyceride (IMTG) storage, we investigated the hypothesis that differential protein content of PLINs and their distribution with LDs may be linked to the diverse lipid storage in muscle between trained and sedentary individuals. Trained (n = 11) and sedentary (n = 10) subjects, matched for age, sex and body mass index, received either a 6 h lipid or glycerol infusion in the setting of a concurrent hyperinsulinaemic-euglycaemic clamp. Sequential muscle biopsies (0, 2 and 6 h) were analysed using confocal immunofluorescence microscopy for fibre type-specific IMTG content and PLIN associations with LDs. In both groups, lipid infusion increased IMTG content in type I fibres (trained: +62%, sedentary: +79%; P < 0.05) but did not affect PLIN protein content. At baseline, PLIN2 (+65%), PLIN3 (+105%) and PLIN5 (+53%; all P < 0.05) protein content was higher in trained compared to sedentary individuals. In trained individuals, lipid infusion increased the number of LDs associated with PLIN2 (+27%), PLIN3 (+73%) and PLIN5 (+40%; all P < 0.05) in type I fibres. By contrast, in sedentary individuals, lipid infusion only increased the number of LDs not associated with PLIN proteins. Acute free fatty acid elevation therefore induces a redistribution of PLIN proteins to an expanded LD pool in trained individuals only and this may be part of the mechanism that enables fatty acids to be stored in IMTG.
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Affiliation(s)
- S O Shepherd
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - J A Strauss
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Q Wang
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, MN, USA
| | - J J Dube
- Department of Biology, Chatham University, Pittsburgh, PA, USA
| | - B Goodpaster
- Translational Research Institute for Metabolism & Diabetes, Florida Hospital, Orlando, FL, USA
| | - D G Mashek
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - L S Chow
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
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18
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Watt MJ, Cheng Y. Triglyceride metabolism in exercising muscle. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1250-1259. [PMID: 28652193 DOI: 10.1016/j.bbalip.2017.06.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 06/15/2017] [Accepted: 06/20/2017] [Indexed: 12/21/2022]
Abstract
Triglycerides are stored within lipid droplets in skeletal muscle and can be hydrolyzed to produce fatty acids for energy production through β-oxidation and oxidative phosphorylation. While there was some controversy regarding the quantitative importance of intramyocellular triglyceride (IMTG) as a metabolic substrate, recent advances in proton magnetic resonance spectroscopy and confocal microscopy support earlier tracer and biopsy studies demonstrating a substantial contribution of IMTG to energy production, particularly during moderate-intensity endurance exercise. This review provides an update on the understanding of IMTG utilization during exercise, with a focus on describing the key regulatory proteins that control IMTG breakdown and how these proteins respond to acute exercise and in the adaptation to exercise training. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
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Affiliation(s)
- Matthew J Watt
- Metabolic Disease and Obesity program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia; Department of Physiology, Monash University, Clayton, Victoria 3800, Australia.
| | - Yunsheng Cheng
- Metabolic Disease and Obesity program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia; Department of Physiology, Monash University, Clayton, Victoria 3800, Australia
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19
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Lund J, Rustan AC, Løvsletten NG, Mudry JM, Langleite TM, Feng YZ, Stensrud C, Brubak MG, Drevon CA, Birkeland KI, Kolnes KJ, Johansen EI, Tangen DS, Stadheim HK, Gulseth HL, Krook A, Kase ET, Jensen J, Thoresen GH. Exercise in vivo marks human myotubes in vitro: Training-induced increase in lipid metabolism. PLoS One 2017; 12:e0175441. [PMID: 28403174 PMCID: PMC5389842 DOI: 10.1371/journal.pone.0175441] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 03/27/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND AIMS Physical activity has preventive as well as therapeutic benefits for overweight subjects. In this study we aimed to examine effects of in vivo exercise on in vitro metabolic adaptations by studying energy metabolism in cultured myotubes isolated from biopsies taken before and after 12 weeks of extensive endurance and strength training, from healthy sedentary normal weight and overweight men. METHODS Healthy sedentary men, aged 40-62 years, with normal weight (body mass index (BMI) < 25 kg/m2) or overweight (BMI ≥ 25 kg/m2) were included. Fatty acid and glucose metabolism were studied in myotubes using [14C]oleic acid and [14C]glucose, respectively. Gene and protein expressions, as well as DNA methylation were measured for selected genes. RESULTS The 12-week training intervention improved endurance, strength and insulin sensitivity in vivo, and reduced the participants' body weight. Biopsy-derived cultured human myotubes after exercise showed increased total cellular oleic acid uptake (30%), oxidation (46%) and lipid accumulation (34%), as well as increased fractional glucose oxidation (14%) compared to cultures established prior to exercise. Most of these exercise-induced increases were significant in the overweight group, whereas the normal weight group showed no change in oleic acid or glucose metabolism. CONCLUSIONS 12 weeks of combined endurance and strength training promoted increased lipid and glucose metabolism in biopsy-derived cultured human myotubes, showing that training in vivo are able to induce changes in human myotubes that are discernible in vitro.
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Affiliation(s)
- Jenny Lund
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
- * E-mail:
| | - Arild C. Rustan
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Nils G. Løvsletten
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Jonathan M. Mudry
- Integrative Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Torgrim M. Langleite
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Yuan Z. Feng
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Camilla Stensrud
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Mari G. Brubak
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Christian A. Drevon
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Kåre I. Birkeland
- Department of Endocrinology, Morbid Obesity and Preventive Medicine, Oslo, University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Kristoffer J. Kolnes
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Egil I. Johansen
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Daniel S. Tangen
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Hans K. Stadheim
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Hanne L. Gulseth
- Department of Endocrinology, Morbid Obesity and Preventive Medicine, Oslo, University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Anna Krook
- Integrative Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Eili T. Kase
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Jørgen Jensen
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - G. Hege Thoresen
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
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20
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Kohe S, Colmenero I, McConville C, Peet A. Immunohistochemical staining of lipid droplets with adipophilin in paraffin-embedded glioma tissue identifies an association between lipid droplets and tumour grade. ACTA ACUST UNITED AC 2017. [DOI: 10.7243/2055-091x-4-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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21
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Strauss JA, Shaw CS, Bradley H, Wilson OJ, Dorval T, Pilling J, Wagenmakers AJM. Immunofluorescence microscopy of SNAP23 in human skeletal muscle reveals colocalization with plasma membrane, lipid droplets, and mitochondria. Physiol Rep 2016; 4:e12662. [PMID: 26733245 PMCID: PMC4760398 DOI: 10.14814/phy2.12662] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 11/27/2015] [Accepted: 11/30/2015] [Indexed: 11/24/2022] Open
Abstract
Synaptosomal-associated protein 23 (SNAP23) is a SNARE protein expressed abundantly in human skeletal muscle. Its established role is to mediate insulin-stimulated docking and fusion of glucose transporter 4 (GLUT4) with the plasma membrane. Recent in vitro research has proposed that SNAP23 may also play a role in the fusion of growing lipid droplets (LDs) and the channeling of LD-derived fatty acids (FAs) into neighboring mitochondria for β-oxidation. This study investigates the subcellular distribution of SNAP23 in human skeletal muscle using immunofluorescence microscopy to confirm that SNAP23 localization supports the three proposed metabolic roles. Percutaneous biopsies were obtained from the m. vastus lateralis of six lean, healthy males in the rested, overnight fasted state. Cryosections were stained with antibodies targeting SNAP23, the mitochondrial marker cytochrome c oxidase and the plasma membrane marker dystrophin, whereas intramuscular LDs were stained using the neutral lipid dye oil red O. SNAP23 displayed areas of intense punctate staining in the intracellular regions of all muscle fibers and continuous intense staining in peripheral regions of the cell. Quantitation of confocal microscopy images showed colocalization of SNAP23 with the plasma membrane marker dystrophin (Pearson's correlation coefficient r = 0.50 ± 0.01). The intense punctate intracellular staining colocalized primarily with the mitochondrial marker cytochrome C oxidase (r = 0.50 ± 0.012) and to a lesser extent with LDs (r = 0.21 ± 0.01) visualized with oil red O. We conclude that the observed subcellular distribution of SNAP23 in human skeletal muscle supports the three aforementioned metabolic roles.
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Affiliation(s)
- Juliette A Strauss
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Christopher S Shaw
- Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Helen Bradley
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, UK
| | - Oliver J Wilson
- Institute for Sport, Physical Activity and Leisure, Carnegie Faculty, Leeds Beckett University, Leeds, UK
| | | | | | - Anton J M Wagenmakers
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
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22
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Pourteymour S, Lee S, Langleite TM, Eckardt K, Hjorth M, Bindesbøll C, Dalen KT, Birkeland KI, Drevon CA, Holen T, Norheim F. Perilipin 4 in human skeletal muscle: localization and effect of physical activity. Physiol Rep 2015; 3:3/8/e12481. [PMID: 26265748 PMCID: PMC4562567 DOI: 10.14814/phy2.12481] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Perilipins (PLINs) coat the surface of lipid droplets and are important for the regulation of lipid turnover. Knowledge about the physiological role of the individual PLINs in skeletal muscle is limited although lipid metabolism is very important for muscle contraction. To determine the effect of long-term exercise on PLINs expression, 26 middle-aged, sedentary men underwent 12 weeks combined endurance and strength training intervention. Muscle biopsies from m. vastus lateralis and subcutaneous adipose tissue were taken before and after the intervention and total gene expression was measured with deep mRNA sequencing. PLIN4 mRNA exhibited the highest expression of all five PLINs in both tissues, and the expression was significantly reduced after long-term exercise in skeletal muscle. Moreover, PLIN4 mRNA expression levels in muscle correlated with the expression of genes involved in de novo phospholipid biosynthesis, with muscular content of phosphatidylethanolamine and phosphatidylcholine, and with the content of subsarcolemmal lipid droplets. The PLIN4 protein was mainly located at the periphery of skeletal muscle fibers, with higher levels in slow-twitch as compared to fast-twitch skeletal muscle fibers. In summary, we report reduced expression of PLIN4 after long-term physical activity, and preferential slow-twitch skeletal muscle fibers and plasma membrane-associated PLIN4 location.
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Affiliation(s)
- Shirin Pourteymour
- Department of Nutrition, Institute of Basic Medical Science, Faculty of Medicine University of Oslo, Oslo, Norway
| | - Sindre Lee
- Department of Nutrition, Institute of Basic Medical Science, Faculty of Medicine University of Oslo, Oslo, Norway
| | - Torgrim M Langleite
- Department of Nutrition, Institute of Basic Medical Science, Faculty of Medicine University of Oslo, Oslo, Norway Department of Endocrinology, Morbid Obesity and Preventive Medicine, Oslo University Hospital and Faculty of Medicine University of Oslo, Oslo, Norway
| | - Kristin Eckardt
- Department of Nutrition, Institute of Basic Medical Science, Faculty of Medicine University of Oslo, Oslo, Norway
| | - Marit Hjorth
- Department of Nutrition, Institute of Basic Medical Science, Faculty of Medicine University of Oslo, Oslo, Norway
| | - Christian Bindesbøll
- Department of Nutrition, Institute of Basic Medical Science, Faculty of Medicine University of Oslo, Oslo, Norway
| | - Knut T Dalen
- Department of Nutrition, Institute of Basic Medical Science, Faculty of Medicine University of Oslo, Oslo, Norway
| | - Kåre I Birkeland
- Department of Endocrinology, Morbid Obesity and Preventive Medicine, Oslo University Hospital and Faculty of Medicine University of Oslo, Oslo, Norway
| | - Christian A Drevon
- Department of Nutrition, Institute of Basic Medical Science, Faculty of Medicine University of Oslo, Oslo, Norway
| | - Torgeir Holen
- Department of Nutrition, Institute of Basic Medical Science, Faculty of Medicine University of Oslo, Oslo, Norway
| | - Frode Norheim
- Department of Nutrition, Institute of Basic Medical Science, Faculty of Medicine University of Oslo, Oslo, Norway
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23
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MacPherson REK, Peters SJ. Piecing together the puzzle of perilipin proteins and skeletal muscle lipolysis. Appl Physiol Nutr Metab 2015; 40:641-51. [PMID: 25971423 DOI: 10.1139/apnm-2014-0485] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The regulation of skeletal muscle lipolysis and fat oxidation is a complex process involving multiple proteins and enzymes. Emerging work indicates that skeletal muscle PLIN proteins likely play a role in the hydrolysis of triglycerides stored in lipid droplets and the passage of fatty acids to the mitochondria for oxidation. In adipocytes, PLIN1 regulates lipolysis by interacting with comparative gene identification-58 (CGI-58), an activator of adipose triglyceride lipase (ATGL). Upon lipolytic stimulation, PLIN1 is phosphorylated, releasing CGI-58 to activate ATGL and initiate triglyceride breakdown. The absence of PLIN1 in skeletal muscle leads us to believe that other PLIN family members undertake this role. The focus of this review is on the PLIN family proteins expressed in skeletal muscle: PLIN2, PLIN3, and PLIN5. To date, most studies involving these PLIN proteins have used nonmuscle tissues and cell cultures to determine their potential roles. Results from work in these models support a role for PLIN proteins in sequestering lipases during basal conditions and in potentially working together for lipase translocation and activity during lipolysis. In skeletal muscle, PLIN2 tends to mirror the lipid content and may play a role in lipid droplet growth and stability through lipase interactions on the lipid droplet surface, whereas the skeletal muscle roles of both PLIN3 and PLIN5 seem to be more complex because they are found not only on the lipid droplet, but also at the mitochondria. Clearly, further work is needed to fully understand the intricate mechanisms by which PLIN proteins contribute to skeletal muscle lipid metabolism.
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Affiliation(s)
- Rebecca E K MacPherson
- a Center for Bone and Muscle Health, Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada.,b Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Sandra J Peters
- a Center for Bone and Muscle Health, Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada
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24
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MacPherson REK, Castelli LM, Miotto PM, Frendo-Cumbo S, Milburn A, Roy BD, LeBlanc PJ, Ward WE, Peters SJ. A maternal high fat diet has long-lasting effects on skeletal muscle lipid and PLIN protein content in rat offspring at young adulthood. Lipids 2015; 50:205-17. [PMID: 25552350 DOI: 10.1007/s11745-014-3985-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 12/16/2014] [Indexed: 01/08/2023]
Abstract
A maternal high fat diet (HFD) can have adverse effects on skeletal muscle development. Skeletal muscle PLIN proteins (PLIN2, 3 and 5) are thought to play critical roles in lipid metabolism, however effects of HFD on PLIN and lipases (HSL, ATGL, CGI-58) in mothers as well as their offspring have yet to be investigated. The primary objective of this study was to determine whether maternal HFD would influence skeletal muscle lipase and PLIN protein content in offspring at weaning (19 d) and young adulthood (3 mo). Female rats (28 d old, n = 9/group) were fed control (CON, AIN93G, 7% soybean oil) or HFD (AIN93G, 20% lard) for 10 weeks prior to mating and throughout pregnancy and lactation. All offspring were weaned to CON [n = 18/group, 1 female and 1 male pup per litter were studied at weaning (19 d) and 3 mo of age]. There was no effect of sex for the main outcomes measured in plantaris, therefore male and female data was combined. Maternal HFD resulted in higher triacylglycerol content in pups at 3 mo (p < 0.05), as well as in the dams (p = 0.015). Maternal HFD resulted in higher PLIN5 content in pups at weaning and 3 mo (p = 0.05). PLIN2 and PLIN5 content decreased at 3 mo versus weaning (p < 0.001). HFD dams had a higher PLIN3 content (p = 0.016). Diet had no effect on ATGL, CGI-58, or HSL content. In conclusion, exposure to a maternal HFD resulted in higher skeletal muscle lipid and PLIN5 content in plantaris of offspring through to young adulthood.
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Affiliation(s)
- Rebecca E K MacPherson
- Faculty of Applied Health Sciences, Center for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada,
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25
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PPARG Modulated Lipid Accumulation in Dairy GMEC via Regulation of ADRP Gene. J Cell Biochem 2014; 116:192-201. [DOI: 10.1002/jcb.24958] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 08/22/2014] [Indexed: 11/07/2022]
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26
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Bosma M. Lipid homeostasis in exercise. Drug Discov Today 2014; 19:1019-23. [PMID: 24632001 DOI: 10.1016/j.drudis.2014.03.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 03/06/2014] [Indexed: 01/08/2023]
Abstract
Fatty acids (FA) are essential energy substrates during endurance exercise. In addition to systemic supply, intramyocellular neutral lipids form an important source of FA for the working muscle. Endurance exercise training is associated with an increased reliance on lipids as a fuel source, has systemic lipid-lowering effects and results in a remodeling of skeletal muscle lipid metabolism toward increased oxidation, neutral lipid storage and turnover. Interestingly, recent studies have indicated common exercise-induced regulatory pathways for genes involved in skeletal muscle mitochondrial oxidative metabolism and lipid droplet (LD) dynamics. In this review, I discuss lipid homeostasis during acute exercise and adaptations in lipid metabolism upon exercise training in the light of recent advances in the field.
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Affiliation(s)
- Madeleen Bosma
- Department of Cell and Molecular Biology, Karolinska Institutet, PO Box 285, SE-171 77 Stockholm, Sweden.
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27
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Badin PM, Langin D, Moro C. Dynamics of skeletal muscle lipid pools. Trends Endocrinol Metab 2013; 24:607-15. [PMID: 23988586 DOI: 10.1016/j.tem.2013.08.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 07/22/2013] [Accepted: 08/03/2013] [Indexed: 11/20/2022]
Abstract
Intramyocellular triacylglycerol (IMTG) is emerging as an important energy fuel source during muscle contraction and are adaptively increased in response to exercise, without adverse physiological effects. Paradoxically, elevated IMTG content in obese and type 2 diabetics has been linked to insulin resistance, highlighting the importance of IMTG pools in physiology and pathology. Two separate views suggest that IMTG dynamics are determinant for skeletal muscle fat oxidation, and that disruption of IMTG dynamics facilitates the accumulation of lipotoxic intermediates such as diacylglycerols and ceramides that interfere with insulin signaling. Thus, understanding the factors that control IMTG dynamics is crucial. Here we discuss recent literature describing the regulation of IMTG pools with a particular emphasis on lipases and lipid droplet (LD)-associated proteins.
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Affiliation(s)
- Pierre-Marie Badin
- Obesity Research Laboratory, Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche (UMR) 1048, Institute of Metabolic and Cardiovascular Diseases (I2MC), Toulouse, France; University of Toulouse, UMR1048, Paul Sabatier University, Toulouse, France
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28
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Prats C, Gomez-Cabello A, Nordby P, Andersen JL, Helge JW, Dela F, Baba O, Ploug T. An optimized histochemical method to assess skeletal muscle glycogen and lipid stores reveals two metabolically distinct populations of type I muscle fibers. PLoS One 2013; 8:e77774. [PMID: 24204959 PMCID: PMC3813758 DOI: 10.1371/journal.pone.0077774] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 09/05/2013] [Indexed: 11/18/2022] Open
Abstract
Skeletal muscle energy metabolism has been a research focus of physiologists for more than a century. Yet, how the use of intramuscular carbohydrate and lipid energy stores are coordinated during different types of exercise remains a subject of debate. Controversy arises from contradicting data from numerous studies, which used different methodological approaches. Here we review the “pros and cons” of previously used histochemical methods and describe an optimized method to ensure the preservation and specificity of detection of both intramyocellular carbohydrate and lipid stores. For optimal preservation of muscle energy stores, air drying cryosections or cycles of freezing-thawing need to be avoided. Furthermore, optimization of the imaging settings in order to specifically image intracellular lipid droplets stained with oil red O or Bodipy-493/503 is shown. When co-staining lipid droplets with associated proteins, Bodipy-493/503 should be the dye of choice, since oil red O creates precipitates on the lipid droplets blocking the light. In order to increase the specificity of glycogen stain, an antibody against glycogen is used. The resulting method reveals the existence of two metabolically distinct myosin heavy chain I expressing fibers: I-1 fibers have a smaller crossectional area, a higher density of lipid droplets, and a tendency to lower glycogen content compared to I-2 fibers. Type I-2 fibers have similar lipid content than IIA. Exhaustive exercise lead to glycogen depletion in type IIA and IIX fibers, a reduction in lipid droplets density in both type I-1 and I-2 fibers, and a decrease in the size of lipid droplets exclusively in type I-1 fibers.
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Affiliation(s)
- Clara Prats
- Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
| | - Alba Gomez-Cabello
- Faculty of Health and Sport Science, University of Zaragoza, Zaragoza, Spain
| | - Pernille Nordby
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jesper L. Andersen
- Institute of Sports Medicine, Bispebjerg Hospital and Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - Jørn W. Helge
- Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - Flemming Dela
- Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - Otto Baba
- Biostructural Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Thorkil Ploug
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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29
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Jeong J, Bong J, Kim GD, Joo ST, Lee HJ, Baik M. Transcriptome changes favoring intramuscular fat deposition in the longissimus muscle following castration of bulls1. J Anim Sci 2013; 91:4692-704. [DOI: 10.2527/jas.2012-6089] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- J. Jeong
- Division of Animal Genomics and Bioinformatics, National Institute of Animal science, Rural Development Administration, #564 Omockchun-dong, Suwon, 441-706, Republic of Korea
| | - J. Bong
- Department of Molecular Biotechnology, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - G. D. Kim
- Department of Animal Science, Gyeongsang National University, Jinju, 660-701, Republic of Korea
| | - S. T. Joo
- Department of Animal Science, Gyeongsang National University, Jinju, 660-701, Republic of Korea
| | - H.-J. Lee
- Division of Animal Genomics and Bioinformatics, National Institute of Animal science, Rural Development Administration, #564 Omockchun-dong, Suwon, 441-706, Republic of Korea
| | - M. Baik
- Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-921, Republic of Korea
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30
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Conte M, Vasuri F, Trisolino G, Bellavista E, Santoro A, Degiovanni A, Martucci E, D'Errico-Grigioni A, Caporossi D, Capri M, Maier AB, Seynnes O, Barberi L, Musarò A, Narici MV, Franceschi C, Salvioli S. Increased Plin2 expression in human skeletal muscle is associated with sarcopenia and muscle weakness. PLoS One 2013; 8:e73709. [PMID: 23977392 PMCID: PMC3744478 DOI: 10.1371/journal.pone.0073709] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 07/22/2013] [Indexed: 11/28/2022] Open
Abstract
Human aging is associated with a progressive loss of muscle mass and strength and a concomitant fat accumulation in form of inter-muscular adipose tissue, causing skeletal muscle function decline and immobilization. Fat accumulation can also occur as intra-muscular triglycerides (IMTG) deposition in lipid droplets, which are associated with perilipin proteins, such as Perilipin2 (Plin2). It is not known whether Plin2 expression changes with age and if this has consequences on muscle mass and strength. We studied the expression of Plin2 in the vastus lateralis (VL) muscle of both healthy subjects and patients affected by lower limb mobility limitation of different age. We found that Plin2 expression increases with age, this phenomenon being particularly evident in patients. Moreover, Plin2 expression is inversely correlated with quadriceps strength and VL thickness. To investigate the molecular mechanisms underpinning this phenomenon, we focused on IGF-1/p53 network/signalling pathway, involved in muscle physiology. We found that Plin2 expression strongly correlates with increased p53 activation and reduced IGF-1 expression. To confirm these observations made on humans, we studied mice overexpressing muscle-specific IGF-1, which are protected from sarcopenia. These mice resulted almost negative for the expression of Plin2 and p53 at two years of age. We conclude that fat deposition within skeletal muscle in form of Plin2-coated lipid droplets increases with age and is associated with decreased muscle strength and thickness, likely through an IGF-1- and p53-dependent mechanism. The data also suggest that excessive intramuscular fat accumulation could be the initial trigger for p53 activation and consequent loss of muscle mass and strength.
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Affiliation(s)
- Maria Conte
- Department of Experimental, Diagnostic and Specialty Medicine and Interdepartmental Centre L Galvani, CIG, University of Bologna, Bologna, Italy.
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31
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MacPherson REK, Ramos SV, Vandenboom R, Roy BD, Peters SJ. Skeletal muscle PLIN proteins, ATGL and CGI-58, interactions at rest and following stimulated contraction. Am J Physiol Regul Integr Comp Physiol 2013; 304:R644-50. [PMID: 23408028 DOI: 10.1152/ajpregu.00418.2012] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Evidence indicates that skeletal muscle lipid droplet-associated proteins (PLINs) regulate lipolysis through protein-protein interactions on the lipid droplet surface. In adipocytes, PLIN1 is thought to regulate lipolysis by directly interacting with comparative gene identification-58 (CGI-58), an activator of adipose triglyceride lipase (ATGL). Upon lipolytic stimulation, PLIN1 is phosphorylated, releasing CGI-58 to fully activate ATGL and initiate triglyceride breakdown. The absence of PLIN1 in skeletal muscle leads us to believe that other PLIN family members undertake this role. Our purpose was to examine interactions between PLIN2, PLIN3, and PLIN5, with ATGL and its coactivator CGI-58 at rest and following contraction. Isolated rat solei were incubated for 30 min at rest or during 30 min of intermittent tetanic stimulation [150-ms volleys at 60 Hz with a train rate of 20 tetani/min (25°C)] to maximally stimulate intramuscular lipid breakdown. Results show that the interaction between ATGL and CGI-58 increased 128% following contraction (P = 0.041). Further, ATGL interacts with PLIN2, PLIN3, and PLIN5 at rest and following contraction. The PLIN2-ATGL interaction decreased significantly by 21% following stimulation (P = 0.013). Both PLIN3 and PLIN5 coprecipitated with CGI-58 at rest and following contraction, while there was no detectable interaction between PLIN2 and CGI-58 in either condition. Therefore, our findings indicate that in skeletal muscle, during contraction-induced muscle lipolysis, ATGL and CGI-58 strongly associate and that the PLIN proteins work together to regulate lipolysis, in part, by preventing ATGL and CGI-58 interactions at rest.
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Affiliation(s)
- Rebecca E K MacPherson
- Brock University, Department of Kinesiology, Centre for Bone and Muscle Health, St. Catharines, Canada.
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32
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Straub BK, Gyoengyoesi B, Koenig M, Hashani M, Pawella LM, Herpel E, Mueller W, Macher-Goeppinger S, Heid H, Schirmacher P. Adipophilin/perilipin-2 as a lipid droplet-specific marker for metabolically active cells and diseases associated with metabolic dysregulation. Histopathology 2013; 62:617-31. [PMID: 23347084 DOI: 10.1111/his.12038] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 09/28/2012] [Indexed: 11/29/2022]
Abstract
AIMS Lipid droplets (LDs) are dynamic storage compartments for energy-rich fats that are nearly ubiquitously present in eukaryotic cells, exerting tissue-specific functions in metabolically active cell types, and are increased in conditions following cellular damage or lipid overload. The LD-cytoplasm interface is stabilized by amphiphilic proteins of the PAT/perilipin family (perilipin/perilipin-1, adipophilin/perilipin-2, and TIP47/perilipin-3). We evaluated the value of adipophilin immunohistochemistry for the diagnosis of diseases associated with LD accumulation. METHODS AND RESULTS In human tissues, adipophilin-positive LDs were especially prominent in steroidogenic cells of the adrenal gland, testis, and ovary, in hepatocytes and hepatic stellate cells, in cardiac, striated and smooth myocytes, in lactating mammary gland epithelial cells, and in plurivacuolar adipocytes. Variable amounts of adipophilin-positive LDs were also detected almost ubiquitously in epithelial cells of the gastrointestinal tract and skin. In diseases associated with lipid storage, adipophilin was strongly expressed in lipid-laden macrophages in atherosclerosis, in cardiomyopathies, kidney diseases, hepatocyte steatosis, colon ischaemia, and at the border of organ infarcts. CONCLUSIONS Adipophilin immunohistochemistry visualizes small LDs in tissues under physiological and disease conditions that are not visible by conventional light microscopy. Immunohistology for adipophilin may facilitate histomorphological diagnosis of diseases and definition of the extent of metabolic dysregulation, such as in organ infarcts, cardiomyopathies, kidney diseases, and microvesicular steatosis.
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33
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Shepherd SO, Cocks M, Tipton KD, Ranasinghe AM, Barker TA, Burniston JG, Wagenmakers AJM, Shaw CS. Sprint interval and traditional endurance training increase net intramuscular triglyceride breakdown and expression of perilipin 2 and 5. J Physiol 2012; 591:657-75. [PMID: 23129790 DOI: 10.1113/jphysiol.2012.240952] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Intramuscular triglyceride (IMTG) utilization is enhanced by endurance training (ET) and is linked to improved insulin sensitivity. This study first investigated the hypothesis that ET-induced increases in net IMTG breakdown and insulin sensitivity are related to increased expression of perilipin 2 (PLIN2) and perilipin 5 (PLIN5). Second, we hypothesized that sprint interval training (SIT) also promotes increases in IMTG utilization and insulin sensitivity. Sixteen sedentary males performed 6 weeks of either SIT (4-6, 30 s Wingate tests per session, 3 days week(-1)) or ET (40-60 min moderate-intensity cycling, 5 days week(-1)). Training increased resting IMTG content (SIT 1.7-fold, ET 2.4-fold; P < 0.05), concomitant with parallel increases in PLIN2 (SIT 2.3-fold, ET 2.8-fold; P < 0.01) and PLIN5 expression (SIT 2.2-fold, ET 3.1-fold; P < 0.01). Pre-training, 60 min cycling at ∼65% pre-training decreased IMTG content in type I fibres (SIT 17 ± 10%, ET 15 ± 12%; P < 0.05). Following training, a significantly greater breakdown of IMTG in type I fibres occurred during exercise (SIT 27 ± 13%, ET 43 ± 6%; P < 0.05), with preferential breakdown of PLIN2- and particularly PLIN5-associated lipid droplets. Training increased the Matsuda insulin sensitivity index (SIT 56 ± 15%, ET 29 ± 12%; main effect P < 0.05). No training × group interactions were observed for any variables. In conclusion, SIT and ET both increase net IMTG breakdown during exercise and increase in PLIN2 and PLIN5 protein expression. The data are consistent with the hypothesis that increases in PLIN2 and PLIN5 are related to the mechanisms that promote increased IMTG utilization during exercise and improve insulin sensitivity following 6 weeks of SIT and ET.
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Affiliation(s)
- S O Shepherd
- School of Sport & Exercise Sciences, University of Birmingham, Birmingham B15 2TT, UK
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34
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Shaw CS, Shepherd SO, Wagenmakers AJM, Hansen D, Dendale P, van Loon LJC. Prolonged exercise training increases intramuscular lipid content and perilipin 2 expression in type I muscle fibers of patients with type 2 diabetes. Am J Physiol Endocrinol Metab 2012; 303:E1158-65. [PMID: 22949030 PMCID: PMC3492857 DOI: 10.1152/ajpendo.00272.2012] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The aim of the present study was to investigate changes in intramuscular triglyceride (IMTG) content and perilipin 2 expression in skeletal muscle tissue following 6 mo of endurance-type exercise training in type 2 diabetes patients. Ten obese male type 2 diabetes patients (age 62 ± 1 yr, body mass index BMI 31 ± 1 kg/m²) completed three exercise sessions/week consisting of 40 min of continuous endurance-type exercise at 75% V(O₂ peak) for a period of 6 mo. Muscle biopsies collected at baseline and after 2 and 6 mo of intervention were analyzed for IMTG content and perilipin 2 expression using fiber type-specific immunofluorescence microscopy. Endurance-type exercise training reduced trunk body fat by 6 ± 2% and increased whole body oxygen uptake capacity by 13 ± 7% (P < 0.05). IMTG content increased twofold in response to the 6 mo of exercise training in both type I and type II muscle fibers (P < 0.05). A threefold increase in perilipin 2 expression was observed from baseline to 2 and 6 mo of intervention in the type I muscle fibers only (1.1 ± 0.3, 3.4 ± 0.6, and 3.6 ± 0.6% of fibers stained, respectively, P < 0.05). Exercise training induced a 1.6-fold increase in mitochondrial content after 6 mo of training in both type I and type II muscle fibers (P < 0.05). In conclusion, this is the first study to report that prolonged endurance-type exercise training increases the expression of perilipin 2 alongside increases in IMTG content in a type I muscle fiber-type specific manner in type 2 diabetes patients.
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MESH Headings
- Abdominal Fat/pathology
- Adiposity
- Body Mass Index
- Cohort Studies
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Diabetes Mellitus, Type 2/therapy
- Exercise
- Humans
- Insulin Resistance
- Lipid Metabolism
- Male
- Membrane Proteins/metabolism
- Middle Aged
- Mitochondria, Muscle/metabolism
- Mitochondria, Muscle/pathology
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Fast-Twitch/pathology
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle Fibers, Slow-Twitch/pathology
- Overweight/complications
- Oxygen Consumption
- Perilipin-2
- Quadriceps Muscle/metabolism
- Quadriceps Muscle/pathology
- Time Factors
- Triglycerides/metabolism
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Affiliation(s)
- C. S. Shaw
- 1School of Sport and Exercise Sciences, The University of Birmingham, Birmingham, United Kingdom;
- 2Institute of Sport, Exercise, and Active Living, Victoria University, Melbourne, Australia;
| | - S. O. Shepherd
- 1School of Sport and Exercise Sciences, The University of Birmingham, Birmingham, United Kingdom;
| | - A. J. M. Wagenmakers
- 1School of Sport and Exercise Sciences, The University of Birmingham, Birmingham, United Kingdom;
| | - D. Hansen
- 3Jessa Hospital, Heart Centre Hasselt, Hasselt, Belgium;
- 4Faculty of Medicine, Hasselt University, Diepenbeek, Belgium; and
| | - P. Dendale
- 3Jessa Hospital, Heart Centre Hasselt, Hasselt, Belgium;
- 4Faculty of Medicine, Hasselt University, Diepenbeek, Belgium; and
| | - L. J. C. van Loon
- 5Department of Human Movement Sciences, Nutrition and Toxicology Research Institute, Maastricht University Medical Centre, Maastricht, The Netherlands
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Nevalainen M, Kaakinen M, Rahkila P, Metsikkö K. Reversible stress-induced lipid body formation in fast twitch rat myofibers. Exp Cell Res 2012; 318:2191-9. [PMID: 22771721 DOI: 10.1016/j.yexcr.2012.06.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 06/21/2012] [Accepted: 06/23/2012] [Indexed: 11/16/2022]
Abstract
We analyzed the existence of lipid bodies (LBs) in the fast twitch rat flexor digitorum brevis (FDB) myofibers and found that these structures were scarce. However, isolation procedure of the myofibers, heath shock, viral infection or the glycosylation inhibitor tunicamycin induced formation of the LBs, which were stationary structures flanking Z lines. We next infected FDB myofibers with recombinant Semliki Forest virus expressing caveolin 3-yellow fluorescent protein (cav3-YFP) since this chimeric protein was targeted to the LBs facilitating their further analysis. Photobleaching experiments showed that the LBs recovered cav 3-YFP extremely slowly, indicating that they were not continuous with the endoplasmic/sarcoplasmic reticulum. We found, however, that cav3-YFP could move from the LBs to the sarcolemma and this phenomenon was sensitive to Brefeldin A, suggesting that the chimeric protein could be returned from the LBs to the endoplasmic reticulum.
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Affiliation(s)
- Mika Nevalainen
- Department of Anatomy and Cell Biology, Institute of Biomedicine, P.O. Box 5000, Aapistie 7, FI 90014 University of Oulu, Finland
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36
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Bakke SS, Moro C, Nikolić N, Hessvik NP, Badin PM, Lauvhaug L, Fredriksson K, Hesselink MK, Boekschoten MV, Kersten S, Gaster M, Thoresen GH, Rustan AC. Palmitic acid follows a different metabolic pathway than oleic acid in human skeletal muscle cells; lower lipolysis rate despite an increased level of adipose triglyceride lipase. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:1323-33. [DOI: 10.1016/j.bbalip.2012.07.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Revised: 05/31/2012] [Accepted: 07/03/2012] [Indexed: 01/22/2023]
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Coen PM, Goodpaster BH. Role of intramyocelluar lipids in human health. Trends Endocrinol Metab 2012; 23:391-8. [PMID: 22721584 PMCID: PMC4908975 DOI: 10.1016/j.tem.2012.05.009] [Citation(s) in RCA: 176] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 05/21/2012] [Accepted: 05/22/2012] [Indexed: 11/20/2022]
Abstract
Intramyocellular lipid (IMCL) is predominantly stored as intramuscular triglyceride (IMTG) in lipid droplets and is utilized as metabolic fuel during physical exercise. IMTG is also implicated in muscle insulin resistance (IR) in type 2 diabetes. However, it has become apparent that lipid moieties such as ceramide and diacylglycerol are the likely culprits of IR. This article reviews current knowledge of IMCL-mediated IR and important areas of investigation, including myocellular lipid transport and lipid droplet proteins. Several crucial questions remain unanswered, such as the identity of specific ceramide and diacylglycerol species that mediate IR in human muscle and their subcellular location. Quantitative lipidomics and proteomics of targeted subcellular organelles will help to better define the mechanisms underlying pathological IMCL accumulation and IR.
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Affiliation(s)
- Paul M Coen
- Department of Health and Physical Activity, University of Pittsburgh, Trees Hall Rm 134D, Allequippa Street and Darragh Street, Pittsburgh, PA 15260, USA
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38
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Watt MJ, Hoy AJ. Lipid metabolism in skeletal muscle: generation of adaptive and maladaptive intracellular signals for cellular function. Am J Physiol Endocrinol Metab 2012; 302:E1315-28. [PMID: 22185843 DOI: 10.1152/ajpendo.00561.2011] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Fatty acids derived from adipose tissue lipolysis, intramyocellular triacylglycerol lipolysis, or de novo lipogenesis serve a variety of functions in skeletal muscle. The two major fates of fatty acids are mitochondrial oxidation to provide energy for the myocyte and storage within a variety of lipids, where they are stored primarily in discrete lipid droplets or serve as important structural components of membranes. In this review, we provide a brief overview of skeletal muscle fatty acid metabolism and highlight recent notable advances in the field. We then 1) discuss how lipids are stored in and mobilized from various subcellular locations to provide adaptive or maladaptive signals in the myocyte and 2) outline how lipid metabolites or metabolic byproducts derived from the actions of triacylglycerol metabolism or β-oxidation act as positive and negative regulators of insulin action. We have placed an emphasis on recent developments in the lipid biology field with respect to understanding skeletal muscle physiology and discuss unanswered questions and technical limitations for assessing lipid signaling in skeletal muscle.
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Affiliation(s)
- Matthew J Watt
- Biology of Lipid Metabolism Laboratory, Department of Physiology, Monash University, Clayton, Victoria 3800, Australia.
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Shepherd SO, Cocks M, Tipton KD, Ranasinghe AM, Barker TA, Burniston JG, Wagenmakers AJM, Shaw CS. Preferential utilization of perilipin 2-associated intramuscular triglycerides during 1 h of moderate-intensity endurance-type exercise. Exp Physiol 2012; 97:970-80. [DOI: 10.1113/expphysiol.2012.064592] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Gjelstad IMF, Haugen F, Gulseth HL, Norheim F, Jans A, Bakke SS, Raastad T, Tjønna AE, Wisløff U, Blaak EE, Risérus U, Gaster M, Roche HM, Birkeland KI, Drevon CA. Expression of perilipins in human skeletal muscle in vitro and in vivo in relation to diet, exercise and energy balance. Arch Physiol Biochem 2012; 118:22-30. [PMID: 22117101 DOI: 10.3109/13813455.2011.630009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The perilipin proteins enclose intracellular lipid droplets. We describe the mRNA expression of the five perilipins in human skeletal muscle in relation to fatty acid supply, exercise and energy balance. We observed that all perilipins were expressed in skeletal muscle biopsies with the highest mRNA levels of perilipin 2, 4 and 5. Cultured myotubes predominantly expressed perilipin 2 and 3. In vitro, incubation of myotubes with fatty acids enhanced mRNA expression of perilipin 1, 2 and 4. In vivo, low fat diet increased mRNA levels of perilipin 3 and 4. Endurance training, but not strength training, enhanced the expression of perilipin 2 and 3. Perilipin 1 mRNA correlated positively with body fat mass, whereas none of the perilipins were associated with insulin sensitivity. In conclusion, all perilipins mRNAs were expressed in human skeletal muscle. Diet as well as endurance exercise modulated the expression of perilipins.
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Affiliation(s)
- I M F Gjelstad
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Norway.
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41
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MacPherson REK, Herbst EAF, Reynolds EJ, Vandenboom R, Roy BD, Peters SJ. Subcellular localization of skeletal muscle lipid droplets and PLIN family proteins OXPAT and ADRP at rest and following contraction in rat soleus muscle. Am J Physiol Regul Integr Comp Physiol 2011; 302:R29-36. [PMID: 22012700 DOI: 10.1152/ajpregu.00163.2011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Skeletal muscle lipid droplet-associated proteins (PLINs) are thought to regulate lipolysis through protein-protein interactions on the lipid droplet surface. In adipocytes, PLIN2 [adipocyte differentiation-related protein (ADRP)] is found only on lipid droplets, while PLIN5 (OXPAT, expressed only in oxidative tissues) is found both on and off the lipid droplet and may be recruited to lipid droplet membranes when needed. Our purpose was to determine whether PLIN5 is recruited to lipid droplets with contraction and to investigate the myocellular location and colocalization of lipid droplets, PLIN2, and PLIN5. Rat solei were isolated, and following a 30-min equilibration period, they were assigned to one of two groups: 1) 30 min of resting incubation and 2) 30 min of stimulation (n = 10 each). Immunofluorescence microscopy was used to determine subcellular content, distribution, and colocalization of lipid droplets, PLIN2, and PLIN5. There was a main effect for lower lipid and PLIN2 content in stimulated compared with rested muscles (P < 0.05). Lipid droplet distribution declined exponentially from the sarcolemma to the fiber center in the rested muscles (P = 0.001, r(2) = 0.99) and linearly in stimulated muscles (slope = -0.0023 ± 0.0006, P < 0.001, r(2) = 0.93). PLIN2 distribution declined exponentially from the sarcolemma to the fiber center in both rested and stimulated muscles (P < 0.0001, r(2) = 0.99 rest; P = 0.0004, r(2) = 0.98 stimulated), while PLIN5 distribution declined linearly (slope = -0.0085 ± 0.0009, P < 0.0001, r(2) = 0.94 rest; slope=-0.0078 ± 0.0010, P = 0.0003, r(2) = 0.91 stimulated). PLIN5-lipid droplets colocalized at rest with no difference poststimulation (P = 0.47; rest r(2) = 0.55 ± 0.02, stimulated r(2) = 0.58 ± 0.03). PLIN2-lipid droplets colocalized at rest with no difference poststimulation (P = 0.48; rest r(2) = 0.66 ± 0.02, stimulated r(2) = 0.65 ± 0.02). Contrary to our hypothesis, these results show that PLIN5 is not recruited to lipid droplets with contraction in isolated skeletal muscle.
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Affiliation(s)
- Rebecca E K MacPherson
- Brock University, Department of Kinesiology, Centre for Muscle Metabolism and Biophysics, Faculty of Applied Health Sciences, St. Catharines, Ontario, Canada.
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Use of BODIPY (493/503) to visualize intramuscular lipid droplets in skeletal muscle. J Biomed Biotechnol 2011; 2011:598358. [PMID: 21960738 PMCID: PMC3180081 DOI: 10.1155/2011/598358] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Revised: 07/21/2011] [Accepted: 08/02/2011] [Indexed: 11/22/2022] Open
Abstract
Triglyceride storage is altered across various chronic health conditions necessitating various techniques to visualize and quantify lipid droplets (LDs). Here, we describe the utilization of the BODIPY (493/503) dye in skeletal muscle as a means to analyze LDs. We found that the dye was a convenient and simple approach to visualize LDs in both sectioned skeletal muscle and cultured adult single fibers. Furthermore, the dye was effective in both fixed and nonfixed cells, and the staining seemed unaffected by permeabilization. We believe that the use of the BODIPY (493/503) dye is an acceptable alternative and, under certain conditions, a simpler method for visualizing LDs stored within skeletal muscle.
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Gandolfi G, Mazzoni M, Zambonelli P, Lalatta-Costerbosa G, Tronca A, Russo V, Davoli R. Perilipin 1 and perilipin 2 protein localization and gene expression study in skeletal muscles of European cross-breed pigs with different intramuscular fat contents. Meat Sci 2011; 88:631-7. [PMID: 21420243 DOI: 10.1016/j.meatsci.2011.02.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 02/14/2011] [Accepted: 02/17/2011] [Indexed: 11/25/2022]
Abstract
This study investigated the lipid droplet coat proteins perilipin 1 (PLIN1) and perilipin 2 (PLIN2) localization in pig skeletal muscle and their relationship with intramuscular fat (IMF) content. PLIN1 and PLIN2 proteins were immunostained in semimembranosus muscle cross-sections from two groups of samples divergent for IMF and the gene expression was quantified. PLIN1 localized in the periphery of intramuscular adipocytes, whereas PLIN2 localized within myofibers with high lipid content. The high IMF group showed higher total cross-sectional area of PLIN1-stained adipocytes compared with the low IMF group (P<0.05), while the cross-sectional area and percentage of PLIN2-positive myofibers did not differ between IMF-divergent groups. This suggested that IMF content is mainly determined by extra-myocellular lipids. At mRNA level, PLIN2 expression was higher in high IMF muscles (P<0.05). The results indicate for the first time that in pig muscle PLIN1 and PLIN2 proteins are localized in correspondence with extra and intra-myocellular lipids, respectively.
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Affiliation(s)
- G Gandolfi
- Department of Agri-food Protection and Valorization (DIPROVAL), Faculty of Agriculture, University of Bologna, Reggio Emilia, Italy.
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Brackmann C, Gabrielsson B, Svedberg F, Holmaang A, Sandberg AS, Enejder A. Nonlinear microscopy of lipid storage and fibrosis in muscle and liver tissues of mice fed high-fat diets. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:066008. [PMID: 21198182 DOI: 10.1117/1.3505024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Hallmarks of high-fat Western diet intake, such as excessive lipid accumulation in skeletal muscle and liver as well as liver fibrosis, are investigated in tissues from mice using nonlinear microscopy, second harmonic generation (SHG), and coherent anti-Stokes Raman scattering (CARS), supported by conventional analysis methods. Two aspects are presented; intake of standard chow versus Western diet, and a comparison between two high-fat Western diets of different polyunsaturated lipid content. CARS microscopy images of intramyocellular lipid droplets in muscle tissue show an increased amount for Western diet compared to standard diet samples. Even stronger diet impact is found for liver samples, where combined CARS and SHG microscopy visualize clear differences in lipid content and collagen fiber development, the latter indicating nonalcoholic fatty liver disease (NAFLD) and steatohepatitis induced at a relatively early stage for Western diet. Characteristic for NAFLD, the fibrous tissue-containing lipids accumulate in larger structures. This is also observed in CARS images of liver samples from two Western-type diets of different polyunsaturated lipid contents. In summary, nonlinear microscopy has strong potential (further promoted by technical advances toward clinical use) for detection and characterization of steatohepatitis already in its early stages.
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Affiliation(s)
- Christian Brackmann
- Chalmers University of Technology, Department of Chemical and Biological Engineering, Molecular Microscopy, 412 96 Göteborg, Sweden
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Shaw CS, Clark J, Wagenmakers AJM. The effect of exercise and nutrition on intramuscular fat metabolism and insulin sensitivity. Annu Rev Nutr 2010; 30:13-34. [PMID: 20373917 DOI: 10.1146/annurev.nutr.012809.104817] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Intramuscular triacylglycerol (IMTG) is both a dynamic fat-storage depot that can expand during periods of elevated lipid availability and a fatty acid source that can be utilized during periods of increased energy expenditure in active individuals. Although many studies have investigated the lifestyle determinants of IMTG content, the results are far from consistent, and studies attempting to unravel the mechanisms behind IMTG metabolism are in their infancy. The limited evidence available suggests that the enzymes responsible for skeletal muscle lipolysis and IMTG synthesis play an important role in determining the fate of fatty acids and therefore the concentration of lipid metabolites and insulin sensitivity of skeletal muscle. This review provides a summary of current knowledge on the effects of acute and chronic exercise as well as energy intake and macronutrient composition of the diet upon the metabolism of IMTG and the implications for metabolic health.
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Affiliation(s)
- Christopher S Shaw
- School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT United Kingdom.
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Coen PM, Dubé JJ, Amati F, Stefanovic-Racic M, Ferrell RE, Toledo FG, Goodpaster BH. Insulin resistance is associated with higher intramyocellular triglycerides in type I but not type II myocytes concomitant with higher ceramide content. Diabetes 2010; 59:80-8. [PMID: 19833891 PMCID: PMC2797948 DOI: 10.2337/db09-0988] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE We tested the primary hypotheses that sphingolipid and diacylglycerol (DAG) content is higher within insulin-resistant muscle and that the association between intramyocellular triglycerides (IMTG) and insulin resistance is muscle fiber type specific. RESEARCH DESIGN AND METHODS A nested case-control analysis was conducted in 22 obese (BMI >30 kg/m(2)) women who were classified as insulin-resistant (IR; n = 12) or insulin-sensitive (IS; n = 10), determined by hyperinsulinemic-euglycemic clamp (>30% greater in IS compared with IR, P < 0.01). Sphingolipid and DAG content was determined by high-performance liquid chromatography-tandem mass spectrometry. Fiber type-specific IMTG content was histologically determined. Gene expression was determined by quantitative PCR. RESULTS Total (555 +/- 53 vs. 293 +/- 54 pmol/mg protein, P = 0.004), saturated (361 +/- 29 vs. 179 +/- 34 pmol/mg protein, P = 0.001), and unsaturated (198 +/- 29 vs. 114 +/- 21 pmol/mg protein, P = 0.034) ceramides were higher in IR compared with IS. DAG concentrations, however, were similar. IMTG content within type I myocytes, but not type II myocytes, was higher in IR compared with IS subjects (P = 0.005). Insulin sensitivity was negatively correlated with IMTG within type I myocytes (R = -0.51, P = 0.026), but not with IMTG within type II myocytes. The proportion of type I myocytes was lower (41 vs. 59%, P < 0.01) in IR subjects. Several genes involved in lipid droplet and fatty acid metabolism were differentially expressed in IR compared with IS subjects. CONCLUSIONS Human skeletal muscle insulin resistance is related to greater IMTG content in type I but not type II myocytes, to greater ceramide content, and to alterations in gene expression associated with lipid metabolism.
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Affiliation(s)
- Paul M. Coen
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - John J. Dubé
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Francesca Amati
- Department of Health and Physical Activity, School of Education, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Maja Stefanovic-Racic
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Robert E. Ferrell
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Frederico G.S. Toledo
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Bret H. Goodpaster
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
- Corresponding author: Bret H. Goodpaster,
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de Wilde J, Smit E, Snepvangers FJM, de Wit NWJ, Mohren R, Hulshof MFM, Mariman ECM. Adipophilin protein expression in muscle--a possible protective role against insulin resistance. FEBS J 2009; 277:761-73. [PMID: 20030713 DOI: 10.1111/j.1742-4658.2009.07525.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Adipophilin is a 50 kDa protein that belongs to the PAT family (perilipin, adipophilin, TIP47, S3-12 and OXPAT), which comprises proteins involved in the coating of lipid droplets. Little is known about the functional role of adipophilin in muscle. Using the C2C12 cell line as a model, we demonstrate that palmitic acid-treated cells highly express the adipophilin protein in a dose-dependent way. Next, we show that oleic acid is a more potent inducer of adipophilin protein levels than palmitic acid. Cells treated with oleic acid have a higher adipophilin protein expression and higher triglyceride levels but less impairment of insulin signaling than cells treated with palmitic acid. Additionally, we show that peroxisome proliferator-activated receptor (PPAR)alpha, PPARbeta/delta and PPARgamma agonists all increase the expression of the adipophilin protein in C2C12 cells. This effect was most pronounced for the PPARalpha agonist GW7647. Furthermore, the expression of adipophilin as a 37 kDa N-terminally truncated protein is higher in the gastrocnemius than in the quadriceps of C57BL/6J mice, especially after an 8-week high-fat diet. The expression of adipophilin was higher in the muscle of mice fed a 4-week high-fat diet based on olive oil or safflower oil than in mice fed a 4-week high-fat diet based on palm oil. After 2 weeks of intervention, plasma glucose, plasma insulin and the homeostasis model assessment of insulin resistance index were lower in mice fed a 4-week high-fat diet based on olive oil or safflower oil than in mice fed a 4-week high-fat diet based on palm oil. Taken together, the results obtained in the present study indicate that adipophilin protein expression in muscle is involved in maintaining insulin sensitivity.
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Affiliation(s)
- Janneke de Wilde
- Nutrigenomics Consortium, Top Institute Food and Nutrition, Wageningen, The Netherlands.
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Extending the knowledge in histochemistry and cell biology. Histochem Cell Biol 2009; 133:1-40. [PMID: 19946696 DOI: 10.1007/s00418-009-0665-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2009] [Indexed: 01/21/2023]
Abstract
Central to modern Histochemistry and Cell Biology stands the need for visualization of cellular and molecular processes. In the past several years, a variety of techniques has been achieved bridging traditional light microscopy, fluorescence microscopy and electron microscopy with powerful software-based post-processing and computer modeling. Researchers now have various tools available to investigate problems of interest from bird's- up to worm's-eye of view, focusing on tissues, cells, proteins or finally single molecules. Applications of new approaches in combination with well-established traditional techniques of mRNA, DNA or protein analysis have led to enlightening and prudent studies which have paved the way toward a better understanding of not only physiological but also pathological processes in the field of cell biology. This review is intended to summarize articles standing for the progress made in "histo-biochemical" techniques and their manifold applications.
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