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Gottlieb D, Abushamat LA, Nadeau KJ, Regensteiner JG, Reusch JEB, Tommerdahl KL, Rice J, Knaub LA, Monaco CMF, Hawke TJ, Perry CGR, Cree MG, Schauer IE. Muscle mitochondrial function is impaired in adults with type 1 diabetes. J Diabetes Complications 2024; 38:108798. [PMID: 38991492 PMCID: PMC11288176 DOI: 10.1016/j.jdiacomp.2024.108798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 06/09/2024] [Indexed: 07/13/2024]
Abstract
AIMS Type 1 diabetes has been associated with mitochondrial dysfunction. However, the mechanism of this dysfunction in adults remains unclear. METHODS A secondary analysis was conducted using data from several clinical trials measuring in-vivo and ex-vivo mitochondrial function in adults with type 1 diabetes (n = 34, age 38.8 ± 14.6 years) and similarly aged controls (n = 59, age 44.6 ± 13.9 years). In-vivo mitochondrial function was assessed before, during, and after isometric exercise with 31phosphorous magnetic resonance spectroscopy. High resolution respirometry of vastus lateralis muscle tissue was used to assess ex-vivo measures. RESULTS In-vivo data showed higher rates of anaerobic glycolysis (p = 0.013), and a lower maximal mitochondrial oxidative capacity (p = 0.012) and mitochondrial efficiency (p = 0.024) in adults with type 1 diabetes. After adjustment for age and percent body fat maximal mitochondrial capacity (p = 0.014) continued to be lower and anaerobic glycolysis higher (p = 0.040) in adults with type 1 diabetes. Ex-vivo data did not demonstrate significant differences between the two groups. CONCLUSIONS The in-vivo analysis demonstrates that adults with type 1 diabetes have mitochondrial dysfunction. This builds on previous research showing in-vivo mitochondrial dysfunction in youths with type 1 diabetes and suggests that defects in substrate or oxygen delivery may play a role in in-vivo dysfunction.
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Affiliation(s)
- Daniel Gottlieb
- NYU Langone Department of Pediatrics, New York City, NY, USA
| | - Layla A Abushamat
- Department of Medicine, Baylor College of Medicine, 1 Baylor Plaza, BCM 285, Houston TX77030, USA; Department of Medicine, Division of Endocrinology, University of Colorado Anschutz Medical Campus, 12801 E. 17th Ave., 7103, Research 1 South, Aurora, CO 80045, USA
| | - Kristen J Nadeau
- Department of Pediatrics, Section of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Judith G Regensteiner
- Ludeman Family Center for Women's Health Research, 12348 East Montview Boulevard, Mail Stop C-263, Aurora, CO 80045, USA; Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, 12631 East 17th Avenue, B130, Aurora, CO 80045, USA
| | - Jane E B Reusch
- Ludeman Family Center for Women's Health Research, 12348 East Montview Boulevard, Mail Stop C-263, Aurora, CO 80045, USA; Department of Medicine, Division of Endocrinology, University of Colorado Anschutz Medical Campus, 12801 E. 17th Ave., 7103, Research 1 South, Aurora, CO 80045, USA; Department of Medicine, Division of Endocrinology, Rocky Mountain Regional Veterans Affairs Medical Center, 1700 N Wheeling St, Aurora, CO 80045, USA
| | - Kalie L Tommerdahl
- Department of Pediatrics, Section of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Ludeman Family Center for Women's Health Research, 12348 East Montview Boulevard, Mail Stop C-263, Aurora, CO 80045, USA; Barbara Davis Center for Diabetes, 1775 Aurora Ct # A140, Aurora, CO 80045, USA
| | - John Rice
- Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado Anschutz Medical Campus, 13001 East 17th Place, 3rd Floor, Mail Stop B119, Aurora, CO 80045, USA
| | - Leslie A Knaub
- Department of Medicine, Division of Cardiology, University of Colorado Anschutz Medical Campus, 12631 East 17th Avenue, B130, Aurora, CO 80045, USA; Department of Medicine, Division of Endocrinology, Rocky Mountain Regional Veterans Affairs Medical Center, 1700 N Wheeling St, Aurora, CO 80045, USA
| | - Cynthia M F Monaco
- Department of Pathology & Molecular Medicine, McMaster University, Health Sciences Centre, Room 2N15, 1200 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Thomas J Hawke
- Department of Pathology & Molecular Medicine, McMaster University, Health Sciences Centre, Room 2N15, 1200 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Christopher G R Perry
- School of Kinesiology & Health Sciences, Muscle Health Research Centre, York University, Norman Bethune College, 170 Campus Walk Room 341, Toronto, ON M3J 1P3, Canada
| | - Melanie G Cree
- Department of Pediatrics, Section of Pediatric Endocrinology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Irene E Schauer
- Ludeman Family Center for Women's Health Research, 12348 East Montview Boulevard, Mail Stop C-263, Aurora, CO 80045, USA; Department of Medicine, Division of Endocrinology, University of Colorado Anschutz Medical Campus, 12801 E. 17th Ave., 7103, Research 1 South, Aurora, CO 80045, USA; Department of Medicine, Division of Endocrinology, Rocky Mountain Regional Veterans Affairs Medical Center, 1700 N Wheeling St, Aurora, CO 80045, USA.
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2
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Hernandez-Corbacho M, Canals D. Drug Targeting of Acyltransferases in the Triacylglyceride and 1-O-AcylCeramide Biosynthetic Pathways. Mol Pharmacol 2024; 105:166-178. [PMID: 38164582 DOI: 10.1124/molpharm.123.000763] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 11/09/2023] [Accepted: 11/20/2023] [Indexed: 01/03/2024] Open
Abstract
Acyltransferase enzymes (EC 2.3.) are a large group of enzymes that transfer acyl groups to a variety of substrates. This review focuses on fatty acyltransferases involved in the biosynthetic pathways of glycerolipids and sphingolipids and how these enzymes have been pharmacologically targeted in their biologic context. Glycerolipids and sphingolipids, commonly treated independently in their regulation and biologic functions, are put together to emphasize the parallelism in their metabolism and bioactive roles. Furthermore, a newly considered signaling molecule, 1-O-acylceramide, resulting from the acylation of ceramide by DGAT2 enzyme, is discussed. Finally, the implications of DGAT2 as a putative ceramide acyltransferase (CAT) enzyme, with a putative dual role in TAG and 1-O-acylceramide generation, are explored. SIGNIFICANCE STATEMENT: This manuscript reviews the current status of drug development in lipid acyltransferases. These are current targets in metabolic syndrome and other diseases, including cancer. A novel function for a member in this group of lipids has been recently reported in cancer cells. The responsible enzyme and biological implications of this added member are discussed.
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Affiliation(s)
| | - Daniel Canals
- Department of Medicine, Stony Brook University, Stony Brook, New York
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Zhao Y, Chen C, Pan J, Lam SM, Shui G, Yang S, Wu T, Yang N, Tao C, Zhao J, Wang Y. Adipocyte Rnf20 ablation increases the fast-twitch fibers of skeletal muscle via lysophosphatidylcholine 16:0. Cell Mol Life Sci 2023; 80:243. [PMID: 37555936 PMCID: PMC11072846 DOI: 10.1007/s00018-023-04896-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 07/20/2023] [Accepted: 07/23/2023] [Indexed: 08/10/2023]
Abstract
Both adipose tissue and skeletal muscle are highly dynamic tissues and interact at the metabolic and hormonal levels in response to internal and external stress, and they coordinate in maintaining whole-body metabolic homeostasis. In our previous study, we revealed that adipocyte-specific Rnf20 knockout mice (ASKO mice) exhibited lower fat mass but higher lean mass, providing a good model for investigating the adipose-muscle crosstalk and exploring the effect of the adipocyte Rnf20 gene on the physiology and metabolism of skeletal muscle. Here, we confirmed that ASKO mice exhibited the significantly increased body weight and gastrocnemius muscle weight. Fiber-type switching in the soleus muscle of ASKO mice was observed, as evidenced by the increased number of fast-twitch fibers and decreased number of slow-twitch fibers. Serum metabolites with significant alteration in abundance were identified by metabolomic analysis and the elevated lysophosphatidylcholine 16:0 [LysoPC (16:0)] was observed in ASKO mice. In addition, lipidome analysis of gonadal white adipose tissue revealed a significant increase in LysoPCs and LysoPC (16:0) in ASKO mice. Furthermore, knockdown of Rnf20 gene in 3T3-L1 cells significantly increased the secretion of LysoPC, suggesting that LysoPC might be a critical metabolite in the adipose-muscle crosstalk of ASKO mice. Furthermore, in vitro study demonstrated that LysoPC (16:0) could induce the expression of fast-twitch muscle fibers related genes in differentiated C2C12 cells, indicating its potential role in adipose-muscle crosstalk. Taken together, these findings not only expand our understanding of the biological functions of Rnf20 gene in systemic lipid metabolism, but also provide insight into adipose tissue dysfunction-induced physiological alterations in skeletal muscle.
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Affiliation(s)
- Ying Zhao
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Chuanhe Chen
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Jianfei Pan
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Sin Man Lam
- Institute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Guanghou Shui
- Institute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Shulin Yang
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Tianwen Wu
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Ning Yang
- College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Cong Tao
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Jianguo Zhao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Yanfang Wang
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China.
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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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5
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Feeding Rhythm-Induced Hypothalamic Agouti-Related Protein Elevation via Glucocorticoids Leads to Insulin Resistance in Skeletal Muscle. Int J Mol Sci 2021; 22:ijms221910831. [PMID: 34639172 PMCID: PMC8509554 DOI: 10.3390/ijms221910831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/28/2021] [Accepted: 10/05/2021] [Indexed: 11/24/2022] Open
Abstract
Circadian phase shifts in peripheral clocks induced by changes in feeding rhythm often result in insulin resistance. However, whether the hypothalamic control system for energy metabolism is involved in the feeding rhythm-related development of insulin resistance is unknown. Here, we show the physiological significance and mechanism of the involvement of the agouti-related protein (AgRP) in evening feeding-associated alterations in insulin sensitivity. Evening feeding during the active dark period increased hypothalamic AgRP expression and skeletal muscle insulin resistance in mice. Inhibiting AgRP expression by administering an antisense oligo or a glucocorticoid receptor antagonist mitigated these effects. AgRP-producing neuron-specific glucocorticoid receptor-knockout (AgRP-GR-KO) mice had normal skeletal muscle insulin sensitivity even under evening feeding schedules. Hepatic vagotomy enhanced AgRP expression in the hypothalamus even during ad-lib feeding in wild-type mice but not in AgRP-GR-KO mice. The findings of this study indicate that feeding in the late active period may affect hypothalamic AgRP expression via glucocorticoids and induce skeletal muscle insulin resistance.
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Ghnaimawi S, Rebello L, Baum J, Huang Y. DHA but not EPA induces the trans-differentiation of C2C12 cells into white-like adipocytes phenotype. PLoS One 2021; 16:e0249438. [PMID: 34473703 PMCID: PMC8412409 DOI: 10.1371/journal.pone.0249438] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 08/12/2021] [Indexed: 01/21/2023] Open
Abstract
Muscle derived stem cells (MDSCs) and myoblast play an important role in myotube regeneration when muscle tissue is injured. However, these cells can be induced to differentiate into adipocytes once exposed to PPARγ activator like EPA and DHA that are highly suggested during pregnancy. The objective of this study aims at determining the identity of trans-differentiated cells by exploring the effect of EPA and DHA on C2C12 undergoing differentiation into brown and white adipocytes. DHA but not EPA committed C2C12 cells reprograming into white like adipocyte phenotype. Also, DHA promoted the expression of lipolysis regulating genes but had no effect on genes regulating β-oxidation referring to its implication in lipid re-esterification. Furthermore, DHA impaired C2C12 cells differentiation into brown adipocytes through reducing the thermogenic capacity and mitochondrial biogenesis of derived cells independent of UCP1. Accordingly, DHA treated groups showed an increased accumulation of lipid droplets and suppressed mitochondrial maximal respiration and spare respiratory capacity. EPA, on the other hand, reduced myogenesis regulating genes, but no significant differences were observed in the expression of adipogenesis key genes. Likewise, EPA suppressed the expression of WAT signature genes indicating that EPA and DHA have an independent role on white adipogensis. Unlike DHA treatment, EPA supplementation had no effect on the differential of C2C12 cells into brown adipocytes. In conclusion, DHA is a potent adipogenic and lipogenic factor that can change the metabolic profile of muscle cells by increasing myocellular fat.
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Affiliation(s)
- Saeed Ghnaimawi
- Department of Cell and Molecular Biology Program, University of Arkansas, Fayetteville, North Carolina, United States of America
| | - Lisa Rebello
- Department of Cell and Molecular Biology Program, University of Arkansas, Fayetteville, North Carolina, United States of America
| | - Jamie Baum
- Department of Food Science, Division of Agriculture, University of Arkansas, Fayetteville, AR, United States of America
| | - Yan Huang
- Department of Animal Science, Division of Agriculture, University of Arkansas, Fayetteville, North Carolina, United States of America
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7
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Zhao X, Li X, Shi X, Karpac J. Diet-MEF2 interactions shape lipid droplet diversification in muscle to influence Drosophila lifespan. Aging Cell 2020; 19:e13172. [PMID: 32537848 PMCID: PMC7433001 DOI: 10.1111/acel.13172] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 04/05/2020] [Accepted: 05/05/2020] [Indexed: 12/12/2022] Open
Abstract
The number, size, and composition of lipid droplets can be influenced by dietary changes that shift energy substrate availability. This diversification of lipid droplets can promote metabolic flexibility and shape cellular stress responses in unique tissues with distinctive metabolic roles. Using Drosophila, we uncovered a role for myocyte enhancer factor 2 (MEF2) in modulating diet-dependent lipid droplet diversification within adult striated muscle, impacting mortality rates. Muscle-specific attenuation of MEF2, whose chronic activation maintains glucose and mitochondrial homeostasis, leads to the accumulation of large, cholesterol ester-enriched intramuscular lipid droplets in response to high calorie, carbohydrate-sufficient diets. The diet-dependent accumulation of these lipid droplets also correlates with both enhanced stress protection in muscle and increases in organismal lifespan. Furthermore, MEF2 attenuation releases an antagonistic regulation of cell cycle gene expression programs, and up-regulation of Cyclin E is required for diet- and MEF2-dependent diversification of intramuscular lipid droplets. The integration of MEF2-regulated gene expression networks with dietary responses thus plays a critical role in shaping muscle metabolism and function, further influencing organismal lifespan. Together, these results highlight a potential protective role for intramuscular lipid droplets during dietary adaptation.
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Affiliation(s)
- Xiao Zhao
- Department of Molecular and Cellular MedicineTexas A&M University Health Science CenterBryanTXUSA
| | - Xiaotong Li
- Department of Molecular and Cellular MedicineTexas A&M University Health Science CenterBryanTXUSA
| | - Xiangyu Shi
- Department of Molecular and Cellular MedicineTexas A&M University Health Science CenterBryanTXUSA
| | - Jason Karpac
- Department of Molecular and Cellular MedicineTexas A&M University Health Science CenterBryanTXUSA
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8
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Nielsen MH, Sabaratnam R, Pedersen AJT, Højlund K, Handberg A. Acute Exercise Increases Plasma Levels of Muscle-Derived Microvesicles Carrying Fatty Acid Transport Proteins. J Clin Endocrinol Metab 2019; 104:4804-4814. [PMID: 30933285 DOI: 10.1210/jc.2018-02547] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 03/26/2019] [Indexed: 02/03/2023]
Abstract
CONTEXT Microvesicles (MVs) are a class of membrane particles shed by any cell in the body in physiological and pathological conditions. They are considered to be key players in intercellular communication, and with a molecular content reflecting the composition of the cell of origin, they have recently emerged as a promising source of biomarkers in a number of diseases. OBJECTIVE The effects of acute exercise on the plasma concentration of skeletal muscle-derived MVs (SkMVs) carrying metabolically important membrane proteins were examined. PARTICIPANTS Thirteen men with obesity and type 2 diabetes mellitus (T2DM) and 14 healthy male controls with obesity exercised on a cycle ergometer for 60 minutes. INTERVENTIONS Muscle biopsies and blood samples-obtained before exercise, immediately after exercise, and 3 hours into recovery-were collected for the analysis of long-chain fatty acid (LCFA) transport proteins CD36 (a scavenger receptor class B protein) and fatty acid transport protein 4 (FATP4) mRNA content in muscle and for flow cytometric studies on circulating SkMVs carrying either LCFA transport protein. RESULTS Besides establishing a flow cytometric approach for the detection of circulating SkMVs and subpopulations carrying either CD36 or FATP4 and thereby adding proof to their existence, we demonstrated an overall exercise-induced change of SkMVs carrying these LCFA transport proteins. A positive correlation between exercise-induced changes in skeletal muscle CD36 mRNA expression and concentrations of SkMVs carrying CD36 was found in T2DM only. CONCLUSIONS This approach could add important real-time information about the abundance of LCFA transport proteins present on activated muscle cells in subjects with impaired glucose metabolism.
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Affiliation(s)
| | - Rugivan Sabaratnam
- Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark
- Section of Molecular Diabetes and Metabolism, Institute of Molecular Medicine and Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Andreas James Thestrup Pedersen
- Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark
- Section of Molecular Diabetes and Metabolism, Institute of Molecular Medicine and Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Kurt Højlund
- Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark
- Section of Molecular Diabetes and Metabolism, Institute of Molecular Medicine and Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Aase Handberg
- Department of Clinical Biochemistry, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Faculty of Medicine, Aalborg University, Aalborg, Denmark
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9
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Ruebel ML, Piccolo BD, Mercer KE, Pack L, Moutos D, Shankar K, Andres A. Obesity leads to distinct metabolomic signatures in follicular fluid of women undergoing in vitro fertilization. Am J Physiol Endocrinol Metab 2019; 316:E383-E396. [PMID: 30601701 PMCID: PMC6459300 DOI: 10.1152/ajpendo.00401.2018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 12/26/2018] [Accepted: 12/31/2018] [Indexed: 02/07/2023]
Abstract
Although obesity negatively influences the metabolic homeostasis of cells within a broad range of tissues, its impact on oocyte metabolism is not fully understood. Prior evidence suggests that obesity increases expression of oocyte genes associated with inflammation, oxidative stress, and lipid metabolism; however, the metabolic impact of these genetic differences is not known. To address this gap, we conducted an exploratory assessment of the follicular fluid (FF) metabolome in eight overweight/obese (OW) and nine normal-weight (NW) women undergoing in vitro fertilization. FF and serum were collected and analyzed by untargeted metabolomics using gas chromatography-quadrupole time-of-flight mass spectrometry and charged-surface hybrid column-electrospray ionization quadrupole time-of-flight tandem mass spectrometry. Untargeted metabolomics identified obesity-associated changes in FF metabolites related to oxidative stress/antioxidant capacity, xenometabolism/amino acid biosynthesis, and lipid metabolism. Discriminant FF metabolites included elevated uric acid, isothreonic acid, one unknown primary metabolite, and six unknown complex lipids in OW compared with NW women. Conversely, 2-ketoglucose dimethylacetal, aminomalonate, two unknown primary metabolites, and two unknown complex lipids were decreased in FF of OW relative to NW women. Indole-3-propionic acid (IPA), a bacteria-derived metabolite, was also decreased in both FF and serum of OW women ( P < 0.05). The significant correlation between antioxidant IPA in serum and FF ( R = 0.95, P < 0.0001) suggests a potential serum biomarker of FF antioxidant status or reflection of the gut metabolism interaction with the follicle. These results suggest that obesity has important consequences for the follicular environment during the preconception period, a window of time that may be important for lifestyle interventions to ameliorate obesity-associated risk factors.
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Affiliation(s)
- Meghan L Ruebel
- Department of Animal Science and Reproductive and Developmental Sciences Program, Michigan State University , East Lansing, Michigan
- Arkansas Children's Nutrition Center , Little Rock, Arkansas
| | - Brian D Piccolo
- Arkansas Children's Nutrition Center , Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences , Little Rock, Arkansas
| | - Kelly E Mercer
- Arkansas Children's Nutrition Center , Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences , Little Rock, Arkansas
| | - Lindsay Pack
- Arkansas Children's Nutrition Center , Little Rock, Arkansas
| | - Dean Moutos
- Arkansas Fertility and Gynecology Associates , Little Rock, Arkansas
| | - Kartik Shankar
- Arkansas Children's Nutrition Center , Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences , Little Rock, Arkansas
| | - Aline Andres
- Arkansas Children's Nutrition Center , Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences , Little Rock, Arkansas
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Schnell DM, Walton RG, Vekaria HJ, Sullivan PG, Bollinger LM, Peterson CA, Thomas DT. Vitamin D produces a perilipin 2-dependent increase in mitochondrial function in C2C12 myotubes. J Nutr Biochem 2018; 65:83-92. [PMID: 30658160 DOI: 10.1016/j.jnutbio.2018.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/11/2018] [Accepted: 11/10/2018] [Indexed: 02/08/2023]
Abstract
Vitamin D has been connected with increased intramyocellular lipid (IMCL) and has also been shown to increase mitochondrial function and insulin sensitivity. Evidence suggests that perilipin 2 (PLIN2), a perilipin protein upregulated with calcitriol treatment, may be integral to managing increased IMCL capacity and lipid oxidation in skeletal muscle. Therefore, we hypothesized that PLIN2 is required for vitamin D induced IMCL accumulation and increased mitochondrial oxidative function. To address this hypothesis, we treated C2C12 myotubes with 100 nM calcitriol (the active form of vitamin D) and/or PLIN2 siRNA in a four group design and analyzed markers of IMCL accumulation and metabolism using qRT-PCR, cytochemistry, and oxygen consumption assay. Expression of PLIN2, but not PLIN3 or PLIN5 mRNA was increased with calcitriol, and PLIN2 induction was prevented with siRNA knockdown without compensation by other perilipins. PLIN2 knockdown did not appear to prevent lipid accumulation. Calcitriol treatment increased mRNA expression of triglyceride synthesizing genes DGAT1 and DGAT2 and also lipolytic genes ATGL and CGI-58. PLIN2 knockdown decreased the expression of CGI-58 and CPT1, and was required for calcitriol-induced upregulation of DGAT2. Calcitriol increased oxygen consumption rate while PLIN2 knockdown decreased oxygen consumption rate. PLIN2 was required for a calcitriol-induced increase in oxygen consumption driven by mitochondrial complex II. We conclude that calcitriol increases mitochondrial function in myotubes and that this increase is at least in part mediated by PLIN2.
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Affiliation(s)
| | - R Grace Walton
- Department of Rehabilitation Sciences; Center for Muscle Biology.
| | | | | | | | | | - D Travis Thomas
- Department of Clinical Sciences, University of Kentucky, Lexington, KY 40536.
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LPAR5, GNAT3 and partial amino acid transporters messenger RNA expression patterns in digestive tracts, metabolic organs and muscle tissues of growing goats. Animal 2018; 13:1394-1402. [PMID: 30378518 DOI: 10.1017/s1751731118002823] [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: 11/06/2022] Open
Abstract
Sufficient amino acid (AA) transport is essential to ensure the normal physiological function and growth of growing animals. The processes of AA sensing and transport in humans and murine animals, but rarely in goats, have been arousing great interest recently. This study was conducted to investigate the messenger RNA expression patterns of lysophosphatidic acid receptor 5 (LPAR5), guanine nucleotide-binding protein α-transducing 3 (GNAT3) and important partial AA transporters in digestive tracts, metabolic organs and muscles of growing goats. The results showed that these genes were widely expressed in goats, and had different expression patterns. LPAR5, GNAT3, solute carrier (SLC38A2), SLC7A7, SLC7A1 and SLC3A1 were rarely expressed in the rumen, but were highly expressed in the abomasum and intestine which are the main sites of AA absorption. GNAT3, SLC38A1, SLC38A2, SLC6A19, SLC7A7 and SLC7A1 showed comparatively high expression in the pancreas and the vital digestive glands, and the relatively high expression of these nine genes were noted in the tibialis posterior, the active muscle in energy metabolism. The correlation analysis showed that there were certain positive correlation among most genes. The current results indicate that the AA sensing and transport occur extensively in the abomasum and small intestine, metabolic organs and muscle tissues of ruminants, and that related genes have tissue specificity.
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Salazar J, Bermúdez V, Olivar LC, Torres W, Palmar J, Añez R, Ordoñez MG, Rivas JR, Martínez MS, Hernández JD, Graterol M, Rojas J. Insulin resistance indices and coronary risk in adults from Maracaibo city, Venezuela: A cross sectional study. F1000Res 2018; 7:44. [PMID: 30210784 PMCID: PMC6107995 DOI: 10.12688/f1000research.13610.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/03/2018] [Indexed: 09/29/2023] Open
Abstract
Background: Insulin resistance (IR) is a metabolic disorder related to atherosclerosis. Its measurement is of great importance not only as a marker of diabetes but also for cardiovascular disease. The aim of this research study was to evaluate the relationship between various IR indices and coronary risk in an adult population from Maracaibo city, Venezuela. Methods: The Maracaibo City Metabolic Syndrome Prevalence Study is a descriptive, cross-sectional study with random and multi-stage sampling. In this sub study, 1272 individuals of both genders were selected with the measurement of basal insulin and coronary risk according to the Framingham-Wilson formula calibrated for our population. The insulin resistance indices evaluated were HOMA2-IR, triglycerides and glucose index (TyG) and triglycerides/HDL ratio (TG/HDL). The predictive capacity and association between each index and the coronary risk event in 10 years were determined. Results: Of the evaluated population, 55.2% were female, 34.8% had a coronary risk ≥5% in 10 years, with the TG/HDL and TyG indices showing the highest AUC 0.712 (0.681-0.743) and 0.707 (0.675-0.739), respectively; compared to HOMA2-IR. Both were also the indices most associated with increased coronary risk, especially TG/HDL ≥3 with a higher association [OR = 2.83 (1.74-4.61); p<0.01] after multivariable adjustment. Conclusions: TyG (≥4.5) and TG/HDL (≥3) indices showed a great predictive capacity of higher coronary risk, with being TG/HDL more associated even after adjusting for abdominal obesity and hs-CRP. Therefore, these represent useful tools for determining IR.
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Affiliation(s)
- Juan Salazar
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
| | - Valmore Bermúdez
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
- Grupo de Investigación Altos Estudios de Frontera (ALEF), Universidad Simón Bolívar, Cucuta, Colombia
| | - Luis Carlos Olivar
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
| | - Wheeler Torres
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
| | - Jim Palmar
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
| | - Roberto Añez
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
| | - Maria Gratzia Ordoñez
- Centro de Salud San Marcos, Ministerio de Salud Pública, Provincia de Santa Elena, Ecuador
| | - José Ramón Rivas
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
| | - María Sofía Martínez
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
| | - Juan Diego Hernández
- Grupo de Investigación Altos Estudios de Frontera (ALEF), Universidad Simón Bolívar, Cucuta, Colombia
| | - Modesto Graterol
- Grupo de Investigación Altos Estudios de Frontera (ALEF), Universidad Simón Bolívar, Cucuta, Colombia
| | - Joselyn Rojas
- Pulmonary and Critical Care Medicine Department, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
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Salazar J, Bermúdez V, Olivar LC, Torres W, Palmar J, Añez R, Ordoñez MG, Rivas JR, Martínez MS, Hernández JD, Graterol M, Rojas J. Insulin resistance indices and coronary risk in adults from Maracaibo city, Venezuela: A cross sectional study. F1000Res 2018; 7:44. [PMID: 30210784 PMCID: PMC6107995 DOI: 10.12688/f1000research.13610.2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/07/2018] [Indexed: 12/19/2022] Open
Abstract
Background: Insulin resistance (IR) is a metabolic disorder related to atherosclerosis. Its measurement is of great importance not only as a marker of diabetes but also for cardiovascular disease. The aim of this research study was to evaluate the relationship between various IR indices and coronary risk in an adult population from Maracaibo city, Venezuela. Methods: The Maracaibo City Metabolic Syndrome Prevalence Study is a descriptive, cross-sectional study with random and multi-stage sampling. In this sub study, 1272 individuals of both genders were selected with the measurement of basal insulin and coronary risk according to the Framingham-Wilson formula calibrated for our population. The insulin resistance indices evaluated were HOMA2-IR, triglycerides and glucose index (TyG) and triglycerides/HDL ratio (TG/HDL). The predictive capacity and association between each index and the coronary risk event in 10 years were determined. Results: Of the evaluated population, 55.2% were female, 34.8% had a coronary risk ≥5% in 10 years, with the TG/HDL and TyG indices showing the highest AUC 0.712 (0.681-0.743) and 0.707 (0.675-0.739), respectively; compared to HOMA2-IR. Both were also the indices most associated with increased coronary risk, especially TG/HDL ≥3 with a higher association [OR = 2.83 (1.74-4.61); p<0.01] after multivariable adjustment. Conclusions: TyG (≥4.5) and TG/HDL (≥3) indices showed a great predictive capacity of higher coronary risk, with being TG/HDL more associated even after adjusting for abdominal obesity and hs-CRP. Therefore, these represent useful tools for determining IR.
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Affiliation(s)
- Juan Salazar
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
| | - Valmore Bermúdez
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
- Grupo de Investigación Altos Estudios de Frontera (ALEF), Universidad Simón Bolívar, Cucuta, Colombia
| | - Luis Carlos Olivar
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
| | - Wheeler Torres
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
| | - Jim Palmar
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
| | - Roberto Añez
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
| | - Maria Gratzia Ordoñez
- Centro de Salud San Marcos, Ministerio de Salud Pública, Provincia de Santa Elena, Ecuador
| | - José Ramón Rivas
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
| | - María Sofía Martínez
- Endocrine and Metabolic Research Center, University of Zulia, Maracaibo, Venezuela
| | - Juan Diego Hernández
- Grupo de Investigación Altos Estudios de Frontera (ALEF), Universidad Simón Bolívar, Cucuta, Colombia
| | - Modesto Graterol
- Grupo de Investigación Altos Estudios de Frontera (ALEF), Universidad Simón Bolívar, Cucuta, Colombia
| | - Joselyn Rojas
- Pulmonary and Critical Care Medicine Department, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
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14
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Lee J, Narayan VP, Hong EY, Whang WK, Park T. Artemisia Iwayomogi Extract Attenuates High-Fat Diet-Induced Hypertriglyceridemia in Mice: Potential Involvement of the Adiponectin-AMPK Pathway and Very Low Density Lipoprotein Assembly in the Liver. Int J Mol Sci 2017; 18:ijms18081762. [PMID: 28805698 PMCID: PMC5578151 DOI: 10.3390/ijms18081762] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 08/03/2017] [Accepted: 08/11/2017] [Indexed: 01/19/2023] Open
Abstract
This study aimed to examine the protective effect of Artemisia iwayomogi extract (AI) against hypertriglyceridemia induced by a high-fat diet (HFD) in mice and to uncover the underlying molecular mechanisms. C57BL/6N mice were fed chow, HFD, HFD + 0.1% AI, HFD + 0.25% AI, or HFD + 0.5% AI for 10 weeks. The addition of 0.25% and 0.5% AI resulted in dose-dependent improvements in the major parameters of hypertriglyceridemia, including plasma triglyceride, free fatty acids, apolipoprotein B, and lipoprotein lipase, with parallel reductions in body weight gain, hepatic lipid accumulation, and insulin resistance. These beneficial effects were accompanied by the activation of adiponectin-adenosine monophosphate-activated protein kinase (AMPK) mediated signaling cascades in the liver, which downregulated molecules involved in lipogenesis and concurrently upregulated molecules related to fatty acid oxidation. The downregulation of molecules involved in very low density lipoprotein assembly, which was associated with improved hepatic insulin signaling, also appeared to contribute to the AI-induced attenuation of hypertriglyceridemia.
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Affiliation(s)
- Jinhui Lee
- Department of Food and Nutrition, Brain Korea 21 PLUS Project, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.
| | - Vikram P Narayan
- Department of Food and Nutrition, Brain Korea 21 PLUS Project, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.
| | - Eun Young Hong
- Pharmaceutical Botany Laboratory, College of Pharmacy, Chung-Ang University, Heukseok-dong, Dongjak-gu, Seoul 06974, Korea.
| | - Wan Kyunn Whang
- Pharmaceutical Botany Laboratory, College of Pharmacy, Chung-Ang University, Heukseok-dong, Dongjak-gu, Seoul 06974, Korea.
| | - Taesun Park
- Department of Food and Nutrition, Brain Korea 21 PLUS Project, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.
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15
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Luo H, Zhou Y, Hu X, Peng X, Wei H, Peng J, Jiang S. Activation of PPARγ2 by PPARγ1 through a functional PPRE in transdifferentiation of myoblasts to adipocytes induced by EPA. Cell Cycle 2016; 14:1830-41. [PMID: 25892270 DOI: 10.1080/15384101.2015.1033594] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
PPARγ and Wnt signaling are central positive and negative regulators of adipogenesis, respectively. Here we identified that, eicosapentaenoic acid (EPA) could effectively induce the transdifferentiation of myoblasts into adipocytes through modulation of both PPARγ expression and Wnt signaling. During the early stage of transdifferentiation, EPA activates PPARδ and PPARγ1, which in turn targets β-catenin to degradation and down-regulates Wnt/β-catenin signaling, such that the myogenic fate of myoblasts could be switched to adipogenesis. In addition, EPA up-regulates the expression of PPARγ1 by activating RXRα, then PPARγ1 binds to the functional peroxisome proliferator responsive element (PPRE) in the promoter of adipocyte-specific PPARγ2 to continuously activate the expression of PPARγ2 throughout the transdifferentiation process. Our data indicated that EPA acts as a dual-function stimulator of adipogenesis that both inhibits Wnt signaling and induces PPARγ2 expression to facilitate the transdifferentiation program, and the transcriptional activation of PPARγ2 by PPARγ1 is not only the key factor for the transdifferentiation of myoblasts to adipocytes, but also the crucial evidence for successful transdifferentiation. The present findings provided insight for the first time as to how EPA induces the transdifferentiation of myoblasts to adipocytes, but also provide new clues for strategies to prevent and treat some metabolic diseases.
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Key Words
- BSA, bovine serum albumin
- C/EBP, CCAAT/enhancer-binding protein
- DHA, docosahexaenoic acid
- DMEM, Dulbecco's modified Eagle's medium
- EPA, eicosapentaenoic acid
- IMF, intramuscular fat
- PPAR, peroxisome proliferator-activated receptor
- PPARγ1
- PPARγ2
- PPARδ
- PPRE, peroxisome proliferator responsive element
- PUFA, polyunsaturated fatty acids
- RXR, retinoid X receptor.
- Wnt/β-catenin signaling
- eicosapentaenoic acid
- transdifferentiation
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Affiliation(s)
- Hefeng Luo
- a Department of Animal Nutrition and Feed Science; College of Animal Science and Technology; Huazhong Agricultural University ; Wuhan , China
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16
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Chang W, Chen L, Hatch GM. Berberine treatment attenuates the palmitate-mediated inhibition of glucose uptake and consumption through increased 1,2,3-triacyl-sn-glycerol synthesis and accumulation in H9c2 cardiomyocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:352-62. [DOI: 10.1016/j.bbalip.2015.12.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 12/23/2015] [Accepted: 12/24/2015] [Indexed: 01/22/2023]
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17
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Altered Skeletal Muscle Fatty Acid Handling in Subjects with Impaired Glucose Tolerance as Compared to Impaired Fasting Glucose. Nutrients 2016; 8:164. [PMID: 26985905 PMCID: PMC4808892 DOI: 10.3390/nu8030164] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 02/24/2016] [Accepted: 03/09/2016] [Indexed: 12/11/2022] Open
Abstract
Altered skeletal muscle fatty acid (FA) metabolism contributes to insulin resistance. Here, we compared skeletal muscle FA handling between subjects with impaired fasting glucose (IFG; n = 12 (7 males)) and impaired glucose tolerance (IGT; n = 14 (7 males)) by measuring arterio-venous concentration differences across forearm muscle. [²H₂]-palmitate was infused intravenously, labeling circulating endogenous triacylglycerol (TAG) and free fatty acids (FFA), whereas [U-(13)C]-palmitate was incorporated in a high-fat mixed-meal, labeling chylomicron-TAG. Skeletal muscle biopsies were taken to determine muscle TAG, diacylglycerol (DAG), FFA, and phospholipid content, their fractional synthetic rate (FSR) and degree of saturation, and gene expression. Insulin sensitivity was assessed using a hyperinsulinemic-euglycemic clamp. Net skeletal muscle glucose uptake was lower (p = 0.018) and peripheral insulin sensitivity tended to be reduced (p = 0.064) in IGT as compared to IFG subjects. Furthermore, IGT showed higher skeletal muscle extraction of VLDL-TAG (p = 0.043), higher muscle TAG content (p = 0.025), higher saturation of FFA (p = 0.004), lower saturation of TAG (p = 0.017) and a tendency towards a lower TAG FSR (p = 0.073) and a lower saturation of DAG (p = 0.059) versus IFG individuals. Muscle oxidative gene expression was lower in IGT subjects. In conclusion, increased liver-derived TAG extraction and reduced lipid turnover of saturated FA, rather than DAG content, in skeletal muscle accompany the more pronounced insulin resistance in IGT versus IFG subjects.
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18
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Søgaard D, Østergård T, Blachnio-Zabielska AU, Baranowski M, Vigelsø AH, Andersen JL, Dela F, Helge JW. Training Does Not Alter Muscle Ceramide and Diacylglycerol in Offsprings of Type 2 Diabetic Patients Despite Improved Insulin Sensitivity. J Diabetes Res 2016; 2016:2372741. [PMID: 27777958 PMCID: PMC5061984 DOI: 10.1155/2016/2372741] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 09/06/2016] [Accepted: 09/08/2016] [Indexed: 01/08/2023] Open
Abstract
Ceramide and diacylglycerol (DAG) may be involved in the early phase of insulin resistance but data are inconsistent in man. We evaluated if an increase in insulin sensitivity after endurance training was accompanied by changes in these lipids in skeletal muscle. Nineteen first-degree type 2 diabetes Offsprings (Offsprings) (age: 33.1 ± 1.4 yrs; BMI: 26.4 ± 0.4 kg/m2) and sixteen matched Controls (age: 31.3 ± 1.5 yrs; BMI: 25.3 ± 0.7 kg/m2) performed 10 weeks of endurance training three times a week at 70% of VO2max on a bicycle ergometer. Before and after the intervention a hyperinsulinemic-euglycemic clamp and VO2max test were performed and muscle biopsies obtained. Insulin sensitivity was significantly lower in Offsprings compared to control subjects (p < 0.01) but improved in both groups after 10 weeks of endurance training (Off: 17 ± 6%; Con: 12 ± 9%, p < 0.01). The content of muscle ceramide, DAG, and their subspecies were similar between groups and did not change in response to the endurance training except for an overall reduction in C22:0-Cer (p < 0.05). Finally, the intervention induced an increase in AKT protein expression (Off: 27 ± 11%; Con: 20 ± 24%, p < 0.05). This study showed no relation between insulin sensitivity and ceramide or DAG content suggesting that ceramide and DAG are not major players in the early phase of insulin resistance in human muscle.
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Affiliation(s)
- Ditte Søgaard
- Xlab, Centre of Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- *Ditte Søgaard:
| | - Torben Østergård
- Department of Endocrinology and Diabetes M, Aarhus University Hospital, Aarhus Sygehus, Aarhus, Denmark
- Department of Internal Medicine, Regional Hospital Viborg, Viborg, Denmark
| | | | - Marcin Baranowski
- Department of Physiology, Medical University of Bialystok, Bialystok, Poland
| | - Andreas Hansen Vigelsø
- Xlab, Centre of Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Flemming Dela
- Xlab, Centre of Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jørn Wulff Helge
- Xlab, Centre of Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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19
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Bosma M. Lipid droplet dynamics in skeletal muscle. Exp Cell Res 2015; 340:180-6. [PMID: 26515552 DOI: 10.1016/j.yexcr.2015.10.023] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/20/2015] [Accepted: 10/23/2015] [Indexed: 02/07/2023]
Abstract
The skeletal muscle is subjected to high mechanical and energetic demands. Lipid droplets are an important source of energy substrates for the working muscle. Muscle cells contain a variety of lipid droplets, which are fundamentally smaller than those found in adipocytes. This translates into a greater lipid droplet surface area serving as the interface for intracellular lipid metabolism. The skeletal muscle has a high plasticity, it is subjected to major remodeling following training and detraining. This coincides with adaptations in lipid droplet characteristics and dynamics. The majority of lipid droplets in skeletal muscle are located in the subsarcolemmal region or in-between the myofibrils, in close vicinity to mitochondria. The vastly organized nature of skeletal muscle fibers limits organelle mobility. The high metabolic rate and substrate turnover in skeletal muscle demands a strict coordination of intramyocellular lipid metabolism and LD dynamics, in which lipid droplet coat proteins play an important role. This review provides insights into the characteristics, diversity and dynamics of skeletal muscle lipid droplets.
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Affiliation(s)
- Madeleen Bosma
- Department of Cell and Molecular Biology, Karolinska Institutet, P.O. Box 285, SE-171 77 Stockholm, Sweden.
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20
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Li Y, Xu S, Zhang X, Yi Z, Cichello S. Skeletal intramyocellular lipid metabolism and insulin resistance. BIOPHYSICS REPORTS 2015; 1:90-98. [PMID: 26942223 PMCID: PMC4762133 DOI: 10.1007/s41048-015-0013-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 04/10/2015] [Indexed: 12/24/2022] Open
Abstract
Lipids stored in skeletal muscle cells are known as intramyocellular lipid (IMCL). Disorders involving IMCL and its causative factor, circulatory free fatty acids (FFAs), induce a toxic state and ultimately result in insulin resistance (IR) in muscle tissue. On the other hand, intramuscular triglyceride (IMTG), the most abundant component of IMCL and an essential energy source for active skeletal muscle, is different from other IMCLs, as it is stored in lipid droplets and plays a pivotal role in skeletal muscle energy homeostasis. This review discusses the association of FFA-induced ectopic lipid accumulation and IR, with specific emphasis on the relationship between IMCL/IMTG metabolism and IR.
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Affiliation(s)
- Yiran Li
- Department of Biological Science and Biotechnology, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191 China ; National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
| | - Shimeng Xu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China ; University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Xuelin Zhang
- Capital University of Physical Education and Sport, Beijing, 100191 China
| | - Zongchun Yi
- Department of Biological Science and Biotechnology, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191 China
| | - Simon Cichello
- School of Life Sciences, La Trobe University, Melbourne, VIC 3086 Australia
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21
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Fabbrini E, Magkos F. Hepatic Steatosis as a Marker of Metabolic Dysfunction. Nutrients 2015; 7:4995-5019. [PMID: 26102213 PMCID: PMC4488828 DOI: 10.3390/nu7064995] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 06/05/2015] [Accepted: 06/15/2015] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the liver manifestation of the complex metabolic derangements associated with obesity. NAFLD is characterized by excessive deposition of fat in the liver (steatosis) and develops when hepatic fatty acid availability from plasma and de novo synthesis exceeds hepatic fatty acid disposal by oxidation and triglyceride export. Hepatic steatosis is therefore the biochemical result of an imbalance between complex pathways of lipid metabolism, and is associated with an array of adverse changes in glucose, fatty acid, and lipoprotein metabolism across all tissues of the body. Intrahepatic triglyceride (IHTG) content is therefore a very good marker (and in some cases may be the cause) of the presence and the degree of multiple-organ metabolic dysfunction. These metabolic abnormalities are likely responsible for many cardiometabolic risk factors associated with NAFLD, such as insulin resistance, type 2 diabetes mellitus, and dyslipidemia. Understanding the factors involved in the pathogenesis and pathophysiology of NAFLD will lead to a better understanding of the mechanisms responsible for the metabolic complications of obesity, and hopefully to the discovery of novel effective treatments for their reversal.
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Affiliation(s)
- Elisa Fabbrini
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Faidon Magkos
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
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22
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Connor T, Martin SD, Howlett KF, McGee SL. Metabolic remodelling in obesity and type 2 diabetes: pathological or protective mechanisms in response to nutrient excess? Clin Exp Pharmacol Physiol 2014; 42:109-15. [DOI: 10.1111/1440-1681.12315] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Revised: 09/17/2014] [Accepted: 09/19/2014] [Indexed: 12/31/2022]
Affiliation(s)
- Timothy Connor
- Metabolic Remodelling Laboratory; Metabolic Research Unit; School of Medicine; Deakin University; Geelong Vic. Australia
| | - Sheree D Martin
- Metabolic Remodelling Laboratory; Metabolic Research Unit; School of Medicine; Deakin University; Geelong Vic. Australia
| | - Kirsten F Howlett
- Centre for Physical Activity and Nutrition; School of Exercise and Nutrition Sciences; Deakin University; Geelong Vic. Australia
| | - Sean L McGee
- Metabolic Remodelling Laboratory; Metabolic Research Unit; School of Medicine; Deakin University; Geelong Vic. Australia
- Division of Cell Signalling and Metabolism; Baker IDI Heart and Diabetes Institute; Melbourne Vic. Australia
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23
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Variability in myosteatosis and insulin resistance induced by high-fat diet in mouse skeletal muscles. BIOMED RESEARCH INTERNATIONAL 2014; 2014:569623. [PMID: 25197650 PMCID: PMC4147206 DOI: 10.1155/2014/569623] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 07/28/2014] [Indexed: 12/17/2022]
Abstract
Nutrient overload leads to impaired muscle oxidative capacity and insulin sensitivity. However, comparative analyses of the effects of dietary manipulation on skeletal muscles with different fiber composition are lacking. This study aimed to investigate the selective adaptations in the soleus and tibialis anterior muscles evoked by administration of high-fat diet for 12 weeks in 10 mice (HFD mice) compared to 10 animals fed with a normal chow diet (control mice). Mice fed with the HFD diet exhibited hyperlipidemia, hyperinsulinemia, hyperglycemia, and lower exercise capacity in comparison to control mice. In control mice, soleus fibers showed higher lipid content than tibialis anterior fibers. In contrast, the lipid content was similar between the two muscles in HFD mice. Significant differences in markers of muscle mitochondrial production and/or activity as well as of lipid synthesis were detected between HFD mice and control mice, especially in the tibialis anterior. Moreover, translocation of GLUT-4 transporter to the plasma membrane and activation of the insulin signaling pathway were markedly inhibited in the tibialis and slightly reduced in the soleus of HFD mice compared to control mice. Overall, these results show that adaptive responses to dietary manipulation occur in a muscle-specific pattern.
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24
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Gumucio JP, Korn MA, Saripalli AL, Flood MD, Phan AC, Roche SM, Lynch EB, Claflin DR, Bedi A, Mendias CL. Aging-associated exacerbation in fatty degeneration and infiltration after rotator cuff tear. J Shoulder Elbow Surg 2014; 23:99-108. [PMID: 23790676 PMCID: PMC3785561 DOI: 10.1016/j.jse.2013.04.011] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Revised: 03/27/2013] [Accepted: 04/17/2013] [Indexed: 02/01/2023]
Abstract
BACKGROUND Rotator cuff tears are one of the most common musculoskeletal complaints and a substantial source of morbidity in elderly patients. Chronic cuff tears are associated with muscle atrophy and an infiltration of fat to the area, a condition known as "fatty degeneration." To improve the treatment of cuff tears in elderly patients, a greater understanding of the changes in the contractile properties of muscle fibers and the molecular regulation of fatty degeneration is essential. METHODS Using a full-thickness, massive supraspinatus and infraspinatus tear model in elderly rats, we measured fiber contractility and determined changes in fiber type distribution that develop 30 days after tear. We also measured the expression of messenger RNA and micro-RNA transcripts involved in muscle atrophy, lipid accumulation, and matrix synthesis. We hypothesized that a decrease in specific force of muscle fibers, an accumulation of type IIb fibers, and an upregulation in atrophic, fibrogenic, and inflammatory gene expression would occur in torn cuff muscles. RESULTS Thirty days after the tear, we observed a reduction in muscle fiber force and an induction of RNA molecules that regulate atrophy, fibrosis, lipid accumulation, inflammation, and macrophage recruitment. A marked accumulation of advanced glycation end products and a significant accretion of macrophages in areas of fat accumulation were observed. CONCLUSIONS The extent of degenerative changes in old rats was greater than that observed in adults. In addition, we identified that the ectopic fat accumulation that occurs in chronic cuff tears does not occur by activation of canonical intramyocellular lipid storage and synthesis pathways.
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Affiliation(s)
- Jonathan P Gumucio
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Michael A Korn
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Anjali L Saripalli
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Michael D Flood
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Anthony C Phan
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Stuart M Roche
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Evan B Lynch
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Dennis R Claflin
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, MI, USA; Section of Plastic Surgery, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Asheesh Bedi
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Christopher L Mendias
- Department Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
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25
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Grunnet LG, Laurila E, Hansson O, Almgren P, Groop L, Brøns C, Poulsen P, Vaag A. The triglyceride content in skeletal muscle is associated with hepatic but not peripheral insulin resistance in elderly twins. J Clin Endocrinol Metab 2012; 97:4571-7. [PMID: 23055544 DOI: 10.1210/jc.2012-2061] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT AND OBJECTIVE Total muscle triglyceride (MT) content has been associated with insulin resistance. We investigated the predictors and impact of MT on relevant metabolic parameters including peripheral and hepatic insulin resistance in elderly twins. DESIGN AND PARTICIPANTS Seventy-four elderly same-sex twins underwent hyperinsulinemic euglycemic clamps preceded by an iv glucose tolerance test. Aerobic capacity (VO2max) and body composition (dual-energy x-ray absorptiometry scan) were determined in all twins. A biopsy from the vastus lateralis muscle was excised in the fasting state. The muscle triacylglycerol content was analyzed by biochemical extraction from these biopsies. RESULTS The percentage of total body fat was the only independent predictor of MT content. After adjustment for trunk fat percentages and sex, MT level was significantly associated to fasting plasma levels of glucose and insulin as well as hepatic insulin resistance. However, the association was weakened after adjustment for total fat percentages. A 1 SD (34.5 mmol/kg dry weight) increase in MT content was associated with a 24% increase of hepatic insulin resistance. No association between MT content and peripheral insulin sensitivity was observed. CONCLUSION MT content is associated with hepatic but not peripheral insulin resistance in elderly twins. We speculate that MT content may reflect the general ectopic accumulation of triglycerides, including fat in the liver.
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Affiliation(s)
- Louise Groth Grunnet
- Department of Endocrinology, Diabetes, and Metabolism, Rigshospitalet, Tagensvej 20, 2200 Copenhagen, Denmark.
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Brea A, Puzo J. Non-alcoholic fatty liver disease and cardiovascular risk. Int J Cardiol 2012; 167:1109-17. [PMID: 23141876 DOI: 10.1016/j.ijcard.2012.09.085] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 05/26/2012] [Accepted: 09/15/2012] [Indexed: 02/07/2023]
Abstract
The term "Non-alcoholic fatty liver disease" (NAFLD) covers a series of liver lesions similar to those induced by alcohol, but not caused by alcohol use. The importance of NAFLD lies in the high prevalence in Western societies and, from the point of view of the liver, in its progression from steatosis to cirrhosis and liver cancer. More recently, NAFLD has been found to be associated with lipid metabolism disorders, the deposition of fat outside of the adipocytes, insulin resistance and Metabolic Syndrome. Also attributed to NAFLD is a heightened systemic pro-inflammatory state, which accelerates arteriosclerosis, thereby increasing cardiovascular risk and associated cardiovascular events. Here we provide an update to the etiopathogenesis of NAFLD, its influence on cardiovascular disease, and the treatment options.
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Affiliation(s)
- Angel Brea
- Unidad de Lípidos, Servicio de Medicina Interna, Hospital San Pedro, Logroño, Spain
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27
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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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28
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Hutchison SK, Teede HJ, Rachoń D, Harrison CL, Strauss BJ, Stepto NK. Effect of exercise training on insulin sensitivity, mitochondria and computed tomography muscle attenuation in overweight women with and without polycystic ovary syndrome. Diabetologia 2012; 55:1424-34. [PMID: 22246378 DOI: 10.1007/s00125-011-2442-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 12/09/2011] [Indexed: 12/25/2022]
Abstract
AIMS/HYPOTHESIS Polycystic ovary syndrome (PCOS) is an insulin resistant (IR) state. Increased skeletal muscle lipid content and impaired mitochondrial biogenesis have been implicated in the pathogenesis of IR. We investigated whether differences in these variables explain the IR of women affected by PCOS and whether improvements in IR with exercise are reflected by changes in these variables. METHODS Sixteen PCOS and 13 non-PCOS overweight women were assessed, and eight PCOS and seven non-PCOS women were reassessed after 12 weeks of moderate and vigorous exercise training. Outcomes included insulin sensitivity (glucose infusion rate [GIR]), skeletal muscle gene expression and protein abundance, enzyme activity of selected mitochondrial components, and computed tomography (CT) attenuation-estimated muscle lipid. RESULTS GIR was lower in women with PCOS versus those without (p = 0.01) and increased with exercise in both groups. Baseline CT muscle attenuation suggested a trend to less muscle lipid in PCOS, which increased with exercise training, with a difference in the change in muscle lipid (p = 0.01, age-corrected), compared with non-PCOS women. GIR correlated with PGC1A gene expression across the whole group; skeletal muscle expression of mitochondrial biogenesis markers was not different between groups at baseline, or after training. Neither lipid changes nor mitochondrial changes correlated with changes in GIR. CONCLUSIONS/INTERPRETATION Differences in IR in women with and without PCOS were not explained by differences in skeletal muscle lipid or mitochondrial parameters. Improvements in IR with exercise were dissociated from mitochondrial parameters. CT muscle attenuation suggested a differential capacity of PCOS muscle to store lipid compared with non-PCOS. TRIAL REGISTRATION Clinicaltrials.gov ISRCTN84763265. FUNDING National Health & Medical Research Council (Grant number 606553), Monash University and The Jean Hailes Foundation.
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Affiliation(s)
- S K Hutchison
- Jean Hailes Foundation Research, School of Public Health and Preventative Medicine, Monash University, Melbourne, VIC, Australia
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29
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Elevated Adipose Triglyceride Lipase in Newly Diagnosed Type 2 Diabetes Mellitus With Hypertension. Am J Med Sci 2011; 342:452-5. [DOI: 10.1097/maj.0b013e318218482f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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30
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Moreno M, Silvestri E, De Matteis R, de Lange P, Lombardi A, Glinni D, Senese R, Cioffi F, Salzano AM, Scaloni A, Lanni A, Goglia F. 3,5-Diiodo-L-thyronine prevents high-fat-diet-induced insulin resistance in rat skeletal muscle through metabolic and structural adaptations. FASEB J 2011; 25:3312-24. [PMID: 21670063 DOI: 10.1096/fj.11-181982] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The worldwide prevalence of obesity-associated pathologies, including type 2 diabetes, requires thorough investigation of mechanisms and interventions. Recent studies have highlighted thyroid hormone analogs and derivatives as potential agents able to counteract such pathologies. In this study, in rats receiving a high-fat diet (HFD), we analyzed the effects of a 4-wk daily administration of a naturally occurring iodothyronine, 3,5-diiodo-L-thyronine (T2), on the gastrocnemius muscle metabolic/structural phenotype and insulin signaling. The HFD-induced increases in muscle levels of fatty acid translocase (3-fold; P<0.05) and TGs (2-fold, P<0.05) were prevented by T2 (each; P<0.05 vs. HFD). T2 increased insulin-stimulated Akt phosphorylation levels (∼2.5-fold; P<0.05 vs. HFD). T2 induced these effects while sparing muscle mass and without cardiac hypertrophy. T2 increased the muscle contents of fast/glycolytic fibers (2-fold; P<0.05 vs. HFD) and sarcolemmal glucose transporter 4 (3-fold; P<0.05 vs. HFD). Adipocyte differentiation-related protein was predominantly present within the slow/oxidative fibers in HFD-T2. In T2-treated rats (vs. HFD), glycolytic enzymes and associated components were up-regulated (proteomic analysis, significance limit: 2-fold; P<0.05), as was phosphofructokinase activity (by 1.3-fold; P<0.05), supporting the metabolic shift toward a more glycolytic phenotype. These results highlight T2 as a potential therapeutic approach to the treatment of diet-induced metabolic dysfunctions.
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Affiliation(s)
- Maria Moreno
- Dipartimento di Scienze per la Biologia, la Geologia e l'Ambiente, Università degli Studi del Sannio, via Port'Arsa 11, 82100 Benevento, Italy
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31
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Krause MP, Riddell MC, Hawke TJ. Effects of type 1 diabetes mellitus on skeletal muscle: clinical observations and physiological mechanisms. Pediatr Diabetes 2011; 12:345-64. [PMID: 20860561 DOI: 10.1111/j.1399-5448.2010.00699.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Matthew P Krause
- Dept of Pathology & Molecular Medicine, McMaster University, 1200 Main St., W. Hamilton, ON, Canada L8N 3Z5
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Nehlin JO, Just M, Rustan AC, Gaster M. Human myotubes from myoblast cultures undergoing senescence exhibit defects in glucose and lipid metabolism. Biogerontology 2011; 12:349-65. [PMID: 21512720 DOI: 10.1007/s10522-011-9336-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 04/06/2011] [Indexed: 12/23/2022]
Abstract
Adult stem cells are known to have a finite replication potential. Muscle biopsy-derived human satellite cells (SCs) were grown at different passages and differentiated to human myotubes in culture to analyze the functional state of various carbohydrate and lipid metabolic pathways. As the proliferative potential of myoblasts decreased dramatically with passage number, a number of cellular functions were altered: the capacity of myoblasts to fuse and differentiate into myotubes was reduced, and metabolic processes in myotubes such as glucose uptake, glycogen synthesis, glucose oxidation and fatty acid β-oxidation became gradually impaired. Upon insulin stimulation, glucose uptake and glycogen synthesis increased but as the cellular proliferative capacity became gradually exhausted, the response dropped concomitantly. Palmitic acid incorporation into lipids in myotubes decreased with passage number and could be explained by reduced incorporation into diacyl- and triacylglycerols. The levels of long-chain acyl-CoA esters decreased with increased passage number. Late-passage, non-proliferating, myoblast cultures showed strong senescence-associated β-galactosidase activity indicating that the observed metabolic defects accompany the induction of a senescent state. The main function of SCs is regeneration and skeletal muscle-build up. Thus, the metabolic defects observed during aging of SC-derived myotubes could have a role in sarcopenia, the gradual age-related loss of muscle mass and strength.
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Affiliation(s)
- Jan O Nehlin
- Center for Stem Cell Treatment, Department of Clinical Immunology, Odense University Hospital & University of Southern Denmark, Odense, Denmark.
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Ren J, Sherry AD, Malloy CR. 1H MRS of intramyocellular lipids in soleus muscle at 7 T: spectral simplification by using long echo times without water suppression. Magn Reson Med 2011; 64:662-71. [PMID: 20578068 DOI: 10.1002/mrm.22345] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The popular short echo time (1)H MR spectroscopy acquisition method for detection of intramyocellular lipids suffers from spectral overlap due to the large, broad, and asymmetric extramyocellular lipid signals, the time-consuming practice of selecting "lean" voxels for spectroscopy, and the overlap of the extramyocellular lipid signal with the creatine methyl (1)H signal at approximately 3 parts per million (ppm), commonly used as an internal standard. Using an alternative acquisition strategy, spectra with well-resolved intramyocellular lipids resonances were acquired from large volumes (10 to 15 mL) of human soleus muscle in less than 5 min by single-voxel 7-T (1)H MR spectroscopy, using an echo time of 280 ms. From the high-resolution spectra, an average intramyocellular lipid concentration of 7.7 +/- 3.5 mmol/kg muscle was found for 25 healthy subjects (male/female 17/8; age 29.4 +/- 6.6 years). Since water suppression was not required, the (1)H signals from unsaturated intracellular triglycerides at about 5.3 ppm were easily detected, which, in combination with the well-determined -(CH(2))(n)-/CH(3) intensity ratio at long echo time, enabled assessment of the composition of triglycerides in the intramyocellular lipids compartment. Long-echo single-voxel spectroscopy at 7 T offers rapid and convenient acquisition of high-resolution spectra from human soleus muscle.
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Affiliation(s)
- Jimin Ren
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8568, USA
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34
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Timmers S, de Vogel-van den Bosch J, Hesselink MKC, van Beurden D, Schaart G, Ferraz MJ, Losen M, Martinez-Martinez P, De Baets MH, Aerts JMFG, Schrauwen P. Paradoxical increase in TAG and DAG content parallel the insulin sensitizing effect of unilateral DGAT1 overexpression in rat skeletal muscle. PLoS One 2011; 6:e14503. [PMID: 21264296 PMCID: PMC3021516 DOI: 10.1371/journal.pone.0014503] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 12/15/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The involvement of muscle triacylglycerol (TAG) storage in the onset of insulin resistance is questioned and the attention has shifted towards inhibition of insulin signalling by the lipid intermediate diacylglycerol (DAG). The enzyme 1,2-acylCoA:diacylglyceroltransferase-1 (DGAT1) esterifies a fatty acyl-CoA on DAG to form TAG. Therefore, the aim of the present study was to investigate if unilateral overexpression of DGAT1 in adult rat Tibialis anterior (TA) muscle will increase conversion of the lipid intermediate DAG into TAG, thereby improving muscle insulin sensitivity. METHODOLOGY/PRINCIPAL FINDINGS The DGAT1 gene construct was injected in the left TA muscle of male rats on chow or high-fat (45% kcal) diet for three weeks, followed by application of one 800 V/cm and four 80 V/cm pulses, using the contralateral leg as sham-electroporated control. Seven days after electroporation, muscle specific insulin sensitivity was assessed with a hyperinsulinemic euglycemic clamp using 2-deoxy-[3H]glucose. Here, we provide evidence that unilateral overexpression of DGAT1 in TA muscle of male rats is associated with an increased rather than decreased DAG content. Strikingly, this increase in DAG content was accompanied by improved muscle insulin sensitivity. Interestingly, markers of muscle lipolysis and mitochondrial function were also increased in DGAT1 overexpressing muscle. CONCLUSIONS/SIGNIFICANCE We conclude that unilateral DGAT1 overexpression can rescue insulin sensitivity, possibly by increasing DAG and TAG turnover in skeletal muscle. In case of a proper balance between the supply and oxidation of fatty acids in skeletal muscle, the lipid intermediate DAG may not exert harmful effects on insulin signalling.
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Affiliation(s)
- Silvie Timmers
- Top Institute Food and Nutrition (TIFN), Wageningen, The Netherlands
- Department of Human Biology, Maastricht University, Maastricht, The Netherlands
| | - Johan de Vogel-van den Bosch
- Top Institute Food and Nutrition (TIFN), Wageningen, The Netherlands
- Department of Human Biology, Maastricht University, Maastricht, The Netherlands
| | - Matthijs K. C. Hesselink
- Human Movement Sciences, School for Nutrition, Toxicology and Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Denis van Beurden
- Department of Human Biology, Maastricht University, Maastricht, The Netherlands
| | - Gert Schaart
- Human Movement Sciences, School for Nutrition, Toxicology and Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
| | - Maria Joao Ferraz
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Mario Losen
- Department of Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Pilar Martinez-Martinez
- Department of Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Marc H. De Baets
- Department of Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Johannes M. F. G. Aerts
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Patrick Schrauwen
- Top Institute Food and Nutrition (TIFN), Wageningen, The Netherlands
- Department of Human Biology, Maastricht University, Maastricht, The Netherlands
- * E-mail:
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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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Kewalramani G, Bilan PJ, Klip A. Muscle insulin resistance: assault by lipids, cytokines and local macrophages. Curr Opin Clin Nutr Metab Care 2010; 13:382-90. [PMID: 20495453 DOI: 10.1097/mco.0b013e32833aabd9] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
PURPOSE OF REVIEW The present review outlines possible mechanisms by which high fatty acids, associated with high-fat diet and obesity, impose insulin resistance on glucose uptake into skeletal muscle. RECENT FINDINGS It is well established that muscle insulin resistance arises in conditions of high-fatty acid availability, and correlates with accumulation of triglycerides within skeletal muscle fibres. However, it is debated whether triglycerides or other lipid metabolites such as diacylglycerols and ceramides are directly responsible. These lipid metabolites can activate serine kinases that impair insulin signalling. Accumulation of acylcarnitines and reactive oxygen species could be additional causative agents of insulin resistance. Further, the precise defects in insulin signalling in muscle caused by high intramuscular lipid (i.e. lipotoxicity) remain unclear. In parallel, proinflammatory activation within the adipose tissue of obese and high-fat fed animals or humans causes muscle insulin resistance, and is ascribed to circulating inflammatory cytokines. Recent evidence also shows proinflammatory macrophages infiltrating muscle tissue and/or intermuscular adipose tissue, and there is growing evidence that fatty acids trigger macrophages to secrete factors that directly impair insulin actions. These factors are postulated to activate stress-signalling pathways in muscle that act on the same insulin-signalling components affected by lipotoxicity. SUMMARY Altered intramuscular lipid metabolism, circulating cytokines, and inflammatory macrophage infiltration of muscle tissue have been recently linked to muscle insulin resistance provoked by fatty acids. Each is analysed separately in this review, but they may act simultaneously and synergistically to render skeletal muscle insulin-resistant.
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Johansen CT, Gallinger ZR, Wang J, Ban MR, Young TK, Bjerregaard P, Hegele RA. Rare ATGL haplotypes are associated with increased plasma triglyceride concentrations in the Greenland Inuit. Int J Circumpolar Health 2010; 69:3-12. [PMID: 20167152 DOI: 10.3402/ijch.v69i1.17427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVES To genotype common genetic variants found in the adipose triglyceride lipase (ATGL) gene and test them for association with cardiovascular disease risk factors in the Greenland Inuit. STUDY DESIGN Candidate gene association study of discrete and quantitative traits related to cardiovascular health. METHODS ATGL was sequenced in 10 European subjects to identify DNA sequence variants. The identified polymorphisms were subsequently genotyped in a population-based cohort of 1,218 unrelated Greenland Inuit subjects, ascertained from the Greenland Population Study. Genotypes and reconstructed haplotypes were tested for association with cardiovascular disease risk factors using additive, dominant or recessive models, corrected for age, sex and body mass index. RESULTS Five single nucleotide polymorphisms and one 4-base pair deletion were identified in the European sample and were similarly polymorphic in the Greenland Inuit. Independently, variants were not associated with any cardiovascular traits. However, reconstructed rare ATGL haplotypes were associated with increased plasma triglyceride (TG) concentrations compared to the major haplotype under a dominant model (1.21+/-0.7 mmol/L and 1.11+/-0.6 mmol/L, respectively, p=0.006). CONCLUSIONS Rare ATGL haplotypes are associated with increased plasma TG concentrations in the Greenland Inuit.
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Current world literature. Curr Opin Lipidol 2010; 21:148-52. [PMID: 20616627 DOI: 10.1097/mol.0b013e3283390e49] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Fabbrini E, Sullivan S, Klein S. Obesity and nonalcoholic fatty liver disease: biochemical, metabolic, and clinical implications. Hepatology 2010; 51:679-89. [PMID: 20041406 PMCID: PMC3575093 DOI: 10.1002/hep.23280] [Citation(s) in RCA: 1413] [Impact Index Per Article: 100.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Obesity is associated with an increased risk of nonalcoholic fatty liver disease (NAFLD). Steatosis, the hallmark feature of NAFLD, occurs when the rate of hepatic fatty acid uptake from plasma and de novo fatty acid synthesis is greater than the rate of fatty acid oxidation and export (as triglyceride within very low-density lipoprotein). Therefore, an excessive amount of intrahepatic triglyceride (IHTG) represents an imbalance between complex interactions of metabolic events. The presence of steatosis is associated with a constellation of adverse alterations in glucose, fatty acid, and lipoprotein metabolism. It is likely that abnormalities in fatty acid metabolism, in conjunction with adipose tissue, hepatic, and systemic inflammation, are key factors involved in the development of insulin resistance, dyslipidemia, and other cardiometabolic risk factors associated with NAFLD. However, it is not clear whether NAFLD causes metabolic dysfunction or whether metabolic dysfunction is responsible for IHTG accumulation, or possibly both. Understanding the precise factors involved in the pathogenesis and pathophysiology of NAFLD will provide important insights into the mechanisms responsible for the cardiometabolic complications of obesity.
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Affiliation(s)
- Elisa Fabbrini
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO, USA,Center for Clinical and Basic Research, Department of Medical Sciences, IRCCS San Raffaele, Rome, Italy
| | - Shelby Sullivan
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Samuel Klein
- Center for Human Nutrition and Atkins Center of Excellence in Obesity Medicine, Washington University School of Medicine, St. Louis, MO, USA
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Desaturation of excess intramyocellular triacylglycerol in obesity: implications for glycemic control. Int J Obes (Lond) 2009; 34:500-10. [PMID: 20029372 DOI: 10.1038/ijo.2009.264] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
OBJECTIVE Excess intramyocellular triacylglycerol (IMTG), found especially in obese women, is slowly metabolized and, therefore, prone to longer exposure to intracellular desaturases. Accordingly, it was hypothesized that IMTG content correlates inversely with IMTG fatty acid (FA) saturation in sedentary subjects. In addition, it was validated if IMTG palmitic acid is associated with insulin resistance as suggested earlier. DESIGN Cross-sectional human study. SUBJECTS In skeletal muscle biopsies, which were obtained from sedentary subjects (34 women, age 48+/-2 years (27 obese including 7 type 2 diabetes (T2DM), body mass index (BMI)=35.5+/-0.8 kg m(-2)) and 25 men, age 49+/-2 years (20 obese including 6 T2DM, BMI=35.8+/-0.8 kg m(-2))), IMTG FA composition was determined by gas-liquid chromatography after separation from phospholipids by thin-layer chromatography. RESULTS Independently of gender saturated FA correlated inversely with IMTG (P<0.001) and monounsaturated FA (P<0.001) including total unsaturation of FA (P<0.002) correlated positively with IMTG. Obese women exhibited lower total saturated FA (P<0.001) and palmitic acid (P<0.001) than obese men independent of IMTG, the latter of which, however, was increased twofold in obese women compared to obese men (P<0.001). Polyunsaturated and long-chain polyunsaturated FA did not correlate with IMTG. Palmitic acid correlated positively with insulin resistance (homeostasis insulin resistance index, P<0.05), fasting glucose (P<0.01) and glycosylated hemoglobin (P<0.002) both in univariate analysis and after correction for gender and IMTG. CONCLUSION IMTG content correlates inversely with IMTG saturated FA, potentially reflecting a low turnover of excess IMTG prone to in situ desaturation probably by the ubiquitous stearoyl-CoA desaturase-1. IMTG FA composition is gender specific and implicates on insulin sensitivity and glycemic control.
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Abstract
Over a decade ago, the finding of a form of low-grade systemic inflammation ('metaflammation') associated with obesity, insulin resistance and chronic disease proffered a causal explanation for the latter. However, recent work has shown that metaflammation is also associated with several modern lifestyle-related and environmental inducers, with or without obesity. Here, we present accumulating data to show a link between metaflammation and a number of non-microbial environmental and lifestyle stimulants, both with and without obesity. This implies that obesity may often be an accomplice to, as much as an offender in, major metabolic disease. The real (albeit distal) cause of such a disease appears to lie in aspects of the modern techno-industrial environment driving unhealthy lifestyle behaviours. If true, this suggests that while individual weight loss may be a component of chronic disease management, it may be neither 'necessary' nor 'sufficient' to reduce the problem at a population level. Greater multidisciplinary and policy input is needed to modify the economic and political drivers of the modern, obesogenic environment.
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