1
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Boutagy NE, Gamez-Mendez A, Fowler JW, Zhang H, Chaube BK, Esplugues E, Kuo A, Lee S, Horikami D, Zhang J, Citrin KM, Singh AK, Coon BG, Lee MY, Suarez Y, Fernandez-Hernando C, Sessa WC. Dynamic metabolism of endothelial triglycerides protects against atherosclerosis in mice. J Clin Invest 2024; 134:e170453. [PMID: 38175710 PMCID: PMC10866653 DOI: 10.1172/jci170453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024] Open
Abstract
Blood vessels are continually exposed to circulating lipids, and elevation of ApoB-containing lipoproteins causes atherosclerosis. Lipoprotein metabolism is highly regulated by lipolysis, largely at the level of the capillary endothelium lining metabolically active tissues. How large blood vessels, the site of atherosclerotic vascular disease, regulate the flux of fatty acids (FAs) into triglyceride-rich (TG-rich) lipid droplets (LDs) is not known. In this study, we showed that deletion of the enzyme adipose TG lipase (ATGL) in the endothelium led to neutral lipid accumulation in vessels and impaired endothelial-dependent vascular tone and nitric oxide synthesis to promote endothelial dysfunction. Mechanistically, the loss of ATGL led to endoplasmic reticulum stress-induced inflammation in the endothelium. Consistent with this mechanism, deletion of endothelial ATGL markedly increased lesion size in a model of atherosclerosis. Together, these data demonstrate that the dynamics of FA flux through LD affects endothelial cell homeostasis and consequently large vessel function during normal physiology and in a chronic disease state.
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Affiliation(s)
- Nabil E. Boutagy
- Department of Pharmacology
- Vascular Biology and Therapeutics Program, and
| | - Ana Gamez-Mendez
- Department of Pharmacology
- Vascular Biology and Therapeutics Program, and
| | - Joseph W.M. Fowler
- Department of Pharmacology
- Vascular Biology and Therapeutics Program, and
| | - Hanming Zhang
- Vascular Biology and Therapeutics Program, and
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Bal K. Chaube
- Vascular Biology and Therapeutics Program, and
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Enric Esplugues
- Vascular Biology and Therapeutics Program, and
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Andrew Kuo
- Vascular Biology Program, Department of Surgery, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Sungwoon Lee
- Department of Pharmacology
- Vascular Biology and Therapeutics Program, and
| | - Daiki Horikami
- Department of Pharmacology
- Vascular Biology and Therapeutics Program, and
| | - Jiasheng Zhang
- Department of Cardiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kathryn M. Citrin
- Vascular Biology and Therapeutics Program, and
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Abhishek K. Singh
- Department of Pharmacology
- Vascular Biology and Therapeutics Program, and
| | - Brian G. Coon
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Monica Y. Lee
- Department of Physiology and Biophysics, Center for Cardiovascular Research, University of Illinois at Chicago School of Medicine, Chicago, Illinois, USA
| | - Yajaira Suarez
- Vascular Biology and Therapeutics Program, and
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Carlos Fernandez-Hernando
- Vascular Biology and Therapeutics Program, and
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - William C. Sessa
- Department of Pharmacology
- Vascular Biology and Therapeutics Program, and
- Department of Cardiology, Yale University School of Medicine, New Haven, Connecticut, USA
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2
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Hofer P, Grabner GF, König M, Xie H, Bulfon D, Ludwig AE, Wolinski H, Zimmermann R, Zechner R, Heier C. Cooperative lipolytic control of neuronal triacylglycerol by spastic paraplegia-associated enzyme DDHD2 and ATGL. J Lipid Res 2023; 64:100457. [PMID: 37832604 PMCID: PMC10665947 DOI: 10.1016/j.jlr.2023.100457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 10/01/2023] [Accepted: 10/04/2023] [Indexed: 10/15/2023] Open
Abstract
Intracellular lipolysis-the enzymatic breakdown of lipid droplet-associated triacylglycerol (TAG)-depends on the cooperative action of several hydrolytic enzymes and regulatory proteins, together designated as lipolysome. Adipose triglyceride lipase (ATGL) acts as a major cellular TAG hydrolase and core effector of the lipolysome in many peripheral tissues. Neurons initiate lipolysis independently of ATGL via DDHD domain-containing 2 (DDHD2), a multifunctional lipid hydrolase whose dysfunction causes neuronal TAG deposition and hereditary spastic paraplegia. Whether and how DDHD2 cooperates with other lipolytic enzymes is currently unknown. In this study, we further investigated the enzymatic properties and functions of DDHD2 in neuroblastoma cells and primary neurons. We found that DDHD2 hydrolyzes multiple acylglycerols in vitro and substantially contributes to neutral lipid hydrolase activities of neuroblastoma cells and brain tissue. Substrate promiscuity of DDHD2 allowed its engagement at different steps of the lipolytic cascade: In neuroblastoma cells, DDHD2 functioned exclusively downstream of ATGL in the hydrolysis of sn-1,3-diacylglycerol (DAG) isomers but was dispensable for TAG hydrolysis and lipid droplet homeostasis. In primary cortical neurons, DDHD2 exhibited lipolytic control over both, DAG and TAG, and complemented ATGL-dependent TAG hydrolysis. We conclude that neuronal cells use noncanonical configurations of the lipolysome and engage DDHD2 as dual TAG/DAG hydrolase in cooperation with ATGL.
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Affiliation(s)
- Peter Hofer
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Gernot F Grabner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Mario König
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Hao Xie
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; State Key Laboratory of Natural Medicines, Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing, China
| | - Dominik Bulfon
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Anton E Ludwig
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria
| | - Robert Zimmermann
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Christoph Heier
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria.
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3
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Smith JAB, Murach KA, Dyar KA, Zierath JR. Exercise metabolism and adaptation in skeletal muscle. Nat Rev Mol Cell Biol 2023; 24:607-632. [PMID: 37225892 PMCID: PMC10527431 DOI: 10.1038/s41580-023-00606-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2023] [Indexed: 05/26/2023]
Abstract
Viewing metabolism through the lens of exercise biology has proven an accessible and practical strategy to gain new insights into local and systemic metabolic regulation. Recent methodological developments have advanced understanding of the central role of skeletal muscle in many exercise-associated health benefits and have uncovered the molecular underpinnings driving adaptive responses to training regimens. In this Review, we provide a contemporary view of the metabolic flexibility and functional plasticity of skeletal muscle in response to exercise. First, we provide background on the macrostructure and ultrastructure of skeletal muscle fibres, highlighting the current understanding of sarcomeric networks and mitochondrial subpopulations. Next, we discuss acute exercise skeletal muscle metabolism and the signalling, transcriptional and epigenetic regulation of adaptations to exercise training. We address knowledge gaps throughout and propose future directions for the field. This Review contextualizes recent research of skeletal muscle exercise metabolism, framing further advances and translation into practice.
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Affiliation(s)
- Jonathon A B Smith
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Kevin A Murach
- Molecular Mass Regulation Laboratory, Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - Kenneth A Dyar
- Metabolic Physiology, Institute for Diabetes and Cancer, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Juleen R Zierath
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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4
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Kim KH, Jia Z, Snyder M, Chen J, Qiu J, Oprescu SN, Chen X, Syed SA, Yue F, Roseguini BT, Imbalzano AN, Hu C, Kuang S. PRMT5 links lipid metabolism to contractile function of skeletal muscles. EMBO Rep 2023; 24:e57306. [PMID: 37334900 PMCID: PMC10398672 DOI: 10.15252/embr.202357306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/30/2023] [Accepted: 06/05/2023] [Indexed: 06/21/2023] Open
Abstract
Skeletal muscle plays a key role in systemic energy homeostasis besides its contractile function, but what links these functions is poorly defined. Protein Arginine Methyl Transferase 5 (PRMT5) is a well-known oncoprotein but also expressed in healthy tissues with unclear physiological functions. As adult muscles express high levels of Prmt5, we generated skeletal muscle-specific Prmt5 knockout (Prmt5MKO ) mice. We observe reduced muscle mass, oxidative capacity, force production, and exercise performance in Prmt5MKO mice. The motor deficiency is associated with scarce lipid droplets in myofibers due to defects in lipid biosynthesis and accelerated degradation. Specifically, PRMT5 deletion reduces dimethylation and stability of Sterol Regulatory Element-Binding Transcription Factor 1a (SREBP1a), a master regulator of de novo lipogenesis. Moreover, Prmt5MKO impairs the repressive H4R3 symmetric dimethylation at the Pnpla2 promoter, elevating the level of its encoded protein ATGL, the rate-limiting enzyme catalyzing lipolysis. Accordingly, skeletal muscle-specific double knockout of Pnpla2 and Prmt5 normalizes muscle mass and function. Together, our findings delineate a physiological function of PRMT5 in linking lipid metabolism to contractile function of myofibers.
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Affiliation(s)
- Kun Ho Kim
- Department of Animal SciencesPurdue UniversityWest LafayetteINUSA
| | - Zhihao Jia
- Department of Animal SciencesPurdue UniversityWest LafayetteINUSA
| | - Madigan Snyder
- Department of Animal SciencesPurdue UniversityWest LafayetteINUSA
- Department of Biological SciencesPurdue UniversityWest LafayetteINUSA
| | - Jingjuan Chen
- Department of Animal SciencesPurdue UniversityWest LafayetteINUSA
| | - Jiamin Qiu
- Department of Animal SciencesPurdue UniversityWest LafayetteINUSA
| | - Stephanie N Oprescu
- Department of Animal SciencesPurdue UniversityWest LafayetteINUSA
- Department of Biological SciencesPurdue UniversityWest LafayetteINUSA
| | - Xiyue Chen
- Department of Animal SciencesPurdue UniversityWest LafayetteINUSA
| | - Sabriya A Syed
- Department of Biochemistry and Molecular PharmacologyUniversity of Massachusetts Medical SchoolWorcesterMAUSA
| | - Feng Yue
- Department of Animal SciencesPurdue UniversityWest LafayetteINUSA
| | - Bruno T Roseguini
- Department of Health and KinesiologyPurdue UniversityWest LafayetteINUSA
| | - Anthony N Imbalzano
- Department of Biochemistry and Molecular PharmacologyUniversity of Massachusetts Medical SchoolWorcesterMAUSA
| | - Changdeng Hu
- Department of Medicinal Chemistry and Molecular PharmacologyPurdue UniversityWest LafayetteINUSA
- Center for Cancer ResearchPurdue UniversityWest LafayetteINUSA
| | - Shihuan Kuang
- Department of Animal SciencesPurdue UniversityWest LafayetteINUSA
- Center for Cancer ResearchPurdue UniversityWest LafayetteINUSA
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5
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Alekos NS, Kushwaha P, Kim SP, Li Z, Abood A, Dirckx N, Aja S, Kodama J, Garcia-Diaz JG, Otsuru S, Rendina-Ruedy E, Wolfgang MJ, Riddle RC. Mitochondrial β-oxidation of adipose-derived fatty acids by osteoblasts fuels parathyroid hormone-induced bone formation. JCI Insight 2023; 8:e165604. [PMID: 36729662 PMCID: PMC10070112 DOI: 10.1172/jci.insight.165604] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 02/01/2023] [Indexed: 02/03/2023] Open
Abstract
The energetic costs of bone formation require osteoblasts to coordinate their activities with tissues, like adipose, that can supply energy-dense macronutrients. In the case of intermittent parathyroid hormone (PTH) treatment, a strategy used to reduce fracture risk, bone formation is preceded by a change in systemic lipid homeostasis. To investigate the requirement for fatty acid oxidation by osteoblasts during PTH-induced bone formation, we subjected mice with osteoblast-specific deficiency of mitochondrial long-chain β-oxidation as well as mice with adipocyte-specific deficiency for the PTH receptor or adipose triglyceride lipase to an anabolic treatment regimen. PTH increased the release of fatty acids from adipocytes and β-oxidation by osteoblasts, while the genetic mouse models were resistant to the hormone's anabolic effect. Collectively, these data suggest that PTH's anabolic actions require coordinated signaling between bone and adipose, wherein a lipolytic response liberates fatty acids that are oxidized by osteoblasts to fuel bone formation.
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Affiliation(s)
- Nathalie S. Alekos
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Priyanka Kushwaha
- Division of Rheumatology, Inflammation, and Immunity, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Soohyun P. Kim
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Zhu Li
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Abdullah Abood
- Center for Public Health Genomics, School of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Naomi Dirckx
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Susan Aja
- Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Joe Kodama
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jean G. Garcia-Diaz
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Satoru Otsuru
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Elizabeth Rendina-Ruedy
- Department of Medicine and Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Michael J. Wolfgang
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ryan C. Riddle
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Research & Development Service, Baltimore Veterans Administration Medical Center, Baltimore, Maryland, USA
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6
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Yu H, Gao X, Loor JJ, Jiang Q, Fang Z, Hao X, Shi Z, Fan M, Chen M, Li X, Liu G, Wang Z, Li X, Du X. Activation of Transcription Factor EB Is Associated With Adipose Tissue Lipolysis in Dairy Cows With Subclinical Ketosis. Front Vet Sci 2022; 9:816064. [PMID: 35211541 PMCID: PMC8861084 DOI: 10.3389/fvets.2022.816064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/04/2022] [Indexed: 11/20/2022] Open
Abstract
Excessive lipid mobilization for adipose tissue caused by severe negative energy balance is the pathological basis for subclinical ketosis (SCK) in dairy cows. In non-ruminants, transcription factor EB (TFEB) was reported to play a role in the regulation of lipid catabolism, but its role in the control of lipolysis in the bovine is unknown. The present study aimed to determine whether the enhanced TFEB transcriptional activity contributes to lipolysis of adipose tissue in SCK cows, and to explore the possibility of establishing a therapeutic strategy by using TFEB as a target to control lipolysis. Thirty cows with similar lactation number (median = 3, range = 2–4) and days in milk (median = 6 d, range = 3–9) were selected into a healthy control (n = 15) and SCK (n = 15) group, and used for subcutaneous adipose tissue biopsies and blood sampling. Adipocytes from healthy Holstein calves were used as a model for in vitro studies involving treatment with 10 μM isoproterenol (ISO) for 0, 1, 2 and 3 h, 250 nM of the TFEB activator Torin1 for 3 h, or used for transfection with TFEB small interfering RNA for 48 h followed by treatment with 10 μM ISO for 3 h. Compared with healthy cows, adipose tissue in SCK cows showed increased lipolysis accompanied by enhanced TFEB transcriptional activity. In vitro, ISO and Torin1 treatment increased lipolysis and enhanced TFEB transcriptional activity in calf adipocytes. However, knockdown of TFEB attenuated ISO-induced lipolysis in adipocytes. Overall, these findings indicated that enhanced transcriptional activity of TFEB may contribute to lipolysis of adipose tissue in dairy cows with SCK. The regulation of TFEB activity may be an effective therapeutic strategy for controlling overt lipolysis in ketotic cows.
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Affiliation(s)
- Hao Yu
- Key Laboratory of Zoonoses Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Jilin, China
| | - Xinxing Gao
- Key Laboratory of Zoonoses Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Jilin, China
| | - Juan J. Loor
- Mammalian NutriPhysioGenomics, Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana, IL, United States
| | - Qianming Jiang
- Mammalian NutriPhysioGenomics, Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana, IL, United States
| | - Zhiyuan Fang
- Key Laboratory of Zoonoses Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Jilin, China
| | - Xue Hao
- Key Laboratory of Zoonoses Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Jilin, China
| | - Zhen Shi
- Key Laboratory of Zoonoses Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Jilin, China
| | - Minghe Fan
- Key Laboratory of Zoonoses Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Jilin, China
| | - Meng Chen
- Key Laboratory of Zoonoses Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Jilin, China
| | - Xinwei Li
- Key Laboratory of Zoonoses Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Jilin, China
| | - Guowen Liu
- Key Laboratory of Zoonoses Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Jilin, China
| | - Zhe Wang
- Key Laboratory of Zoonoses Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Jilin, China
| | - Xiaobing Li
- College of Veterinary Medicine, Yunnan Agricultural University, Kunming, China
- *Correspondence: Xiaobing Li
| | - Xiliang Du
- Key Laboratory of Zoonoses Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Jilin, China
- Xiliang Du
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7
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Adipose Lipolysis Regulates Cardiac Glucose Uptake and Function in Mice under Cold Stress. Int J Mol Sci 2021; 22:ijms222413361. [PMID: 34948160 PMCID: PMC8703875 DOI: 10.3390/ijms222413361] [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: 10/25/2021] [Revised: 12/07/2021] [Accepted: 12/09/2021] [Indexed: 02/04/2023] Open
Abstract
The heart primarily uses fatty acids as energy substrates. Adipose lipolysis is a major source of fatty acids, particularly under stress conditions. In this study, we showed that mice with selective inactivation of the lipolytic coactivator comparative gene identification-58 (CGI-58) in adipose tissue (FAT-KO mice), relative to their littermate controls, had lower circulating FA levels in the fed and fasted states due to impaired adipose lipolysis. They preferentially utilized carbohydrates as energy fuels and were more insulin sensitive and glucose tolerant. Under cold stress, FAT-KO versus control mice had >10-fold increases in glucose uptake in the hearts but no increases in other tissues examined. Plasma concentrations of atrial natriuretic peptide and cardiac mRNAs for atrial and brain-type natriuretic peptides, two sensitive markers of cardiac remodeling, were also elevated. After one week of cold exposure, FAT-KO mice showed reduced cardiac expression of several mitochondrial oxidative phosphorylation proteins. After one month of cold exposure, hearts of these animals showed depressed functions, reduced SERCA2 protein, and increased proteins for MHC-β, collagen I proteins, Glut1, Glut4 and phospho-AMPK. Thus, CGI-58-dependent adipose lipolysis critically regulates cardiac metabolism and function, especially during cold adaptation. The adipose-heart axis may be targeted for the management of cardiac dysfunction.
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8
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Blumrich A, Vogler G, Dresen S, Diop SB, Jaeger C, Leberer S, Grune J, Wirth EK, Hoeft B, Renko K, Foryst-Ludwig A, Spranger J, Sigrist S, Bodmer R, Kintscher U. Fat-body brummer lipase determines survival and cardiac function during starvation in Drosophila melanogaster. iScience 2021; 24:102288. [PMID: 33889813 PMCID: PMC8050372 DOI: 10.1016/j.isci.2021.102288] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 02/08/2021] [Accepted: 03/04/2021] [Indexed: 12/17/2022] Open
Abstract
The cross talk between adipose tissue and the heart has an increasing importance for cardiac function under physiological and pathological conditions. This study characterizes the role of fat body lipolysis for cardiac function in Drosophila melanogaster. Perturbation of the function of the key lipolytic enzyme, brummer (bmm), an ortholog of the mammalian ATGL (adipose triglyceride lipase) exclusively in the fly's fat body, protected the heart against starvation-induced dysfunction. We further provide evidence that this protection is caused by the preservation of glycerolipid stores, resulting in a starvation-resistant maintenance of energy supply and adequate cardiac ATP synthesis. Finally, we suggest that alterations of lipolysis are tightly coupled to lipogenic processes, participating in the preservation of lipid energy substrates during starvation. Thus, we identified the inhibition of adipose tissue lipolysis and subsequent energy preservation as a protective mechanism against cardiac dysfunction during catabolic stress. A cross talk between fat body and the heart regulates cardiac function in Drosophila Knockdown of fat-body brummer lipase prevents starvation-induced cardiac dysfunction This involves preservation of lipid stores and maintenance of cardiac energy supply Brummer-mediated preservation of fat body lipid stores involves lipolysis and lipogenesis
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Affiliation(s)
- Annelie Blumrich
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, CCR, Hessische Str. 3-4, 10115 Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
- Development, Aging and Regeneration Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Georg Vogler
- Development, Aging and Regeneration Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Sandra Dresen
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, CCR, Hessische Str. 3-4, 10115 Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Soda Balla Diop
- Development, Aging and Regeneration Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Carsten Jaeger
- Federal Institute for Materials Research and Testing (BAM), Berlin, Germany
| | - Sarah Leberer
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, CCR, Hessische Str. 3-4, 10115 Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Jana Grune
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Berlin, Germany
| | - Eva K. Wirth
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Endocrinology and Metabolism, Berlin, Germany
| | - Beata Hoeft
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, CCR, Hessische Str. 3-4, 10115 Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Kostja Renko
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Experimental Endocrinology, Berlin, Germany
| | - Anna Foryst-Ludwig
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, CCR, Hessische Str. 3-4, 10115 Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Joachim Spranger
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Endocrinology and Metabolism, Berlin, Germany
| | - Stephan Sigrist
- Institute of Biology/Genetics, Freie Universität Berlin, Berlin, Germany
| | - Rolf Bodmer
- Development, Aging and Regeneration Program, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Ulrich Kintscher
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, CCR, Hessische Str. 3-4, 10115 Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
- Corresponding author
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9
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ATGL activity regulates GLUT1-mediated glucose uptake and lactate production via TXNIP stability in adipocytes. J Biol Chem 2021; 296:100332. [PMID: 33508319 PMCID: PMC7949114 DOI: 10.1016/j.jbc.2021.100332] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 01/16/2021] [Accepted: 01/22/2021] [Indexed: 01/03/2023] Open
Abstract
Traditionally, lipolysis has been regarded as an enzymatic activity that liberates fatty acids as metabolic fuel. However, recent work has shown that novel substrates, including a variety of lipid compounds such as fatty acids and their derivatives, release lipolysis products that act as signaling molecules and transcriptional modulators. While these studies have expanded the role of lipolysis, the mechanisms underpinning lipolysis signaling are not fully defined. Here, we uncover a new mechanism regulating glucose uptake, whereby activation of lipolysis, in response to elevated cAMP, leads to the stimulation of thioredoxin-interacting protein (TXNIP) degradation. This, in turn, selectively induces glucose transporter 1 surface localization and glucose uptake in 3T3-L1 adipocytes and increases lactate production. Interestingly, cAMP-induced glucose uptake via degradation of TXNIP is largely dependent upon adipose triglyceride lipase (ATGL) and not hormone-sensitive lipase or monoacylglycerol lipase. Pharmacological inhibition or knockdown of ATGL alone prevents cAMP-dependent TXNIP degradation and thus significantly decreases glucose uptake and lactate secretion. Conversely, overexpression of ATGL amplifies the cAMP response, yielding increased glucose uptake and lactate production. Similarly, knockdown of TXNIP elicits enhanced basal glucose uptake and lactate secretion, and increased cAMP further amplifies this phenotype. Overexpression of TXNIP reduces basal and cAMP-stimulated glucose uptake and lactate secretion. As a proof of concept, we replicated these findings in human primary adipocytes and observed TXNIP degradation and increased glucose uptake and lactate secretion upon elevated cAMP signaling. Taken together, our results suggest a crosstalk between ATGL-mediated lipolysis and glucose uptake.
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10
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Seibert JT, Najt CP, Heden TD, Mashek DG, Chow LS. Muscle Lipid Droplets: Cellular Signaling to Exercise Physiology and Beyond. Trends Endocrinol Metab 2020; 31:928-938. [PMID: 32917515 PMCID: PMC7704552 DOI: 10.1016/j.tem.2020.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/09/2020] [Accepted: 08/13/2020] [Indexed: 12/21/2022]
Abstract
Conventionally viewed as energy storage depots, lipid droplets (LDs) play a central role in muscle lipid metabolism and intracellular signaling, as recognized by recent advances in our biological understanding. Specific subpopulations of muscle LDs, defined by location and associated proteins, are responsible for distinct biological functions. In this review, the traditional view of muscle LDs is examined, and the emerging role of LDs in intracellular signaling is highlighted. The effects of chronic and acute exercise on muscle LD metabolism and signaling is discussed. In conclusion, future directions for muscle LD research are identified. The primary focus will be on human studies, with inclusion of select animal/cellular/non-muscle studies as appropriate, to provide the underlying mechanisms driving the observed findings.
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Affiliation(s)
- Jacob T Seibert
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Charles P Najt
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Timothy D Heden
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Douglas G Mashek
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, University of Minnesota, Minneapolis, MN 55455, USA
| | - Lisa S Chow
- Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, University of Minnesota, Minneapolis, MN 55455, USA.
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11
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Adipocyte lipolysis: from molecular mechanisms of regulation to disease and therapeutics. Biochem J 2020; 477:985-1008. [PMID: 32168372 DOI: 10.1042/bcj20190468] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/19/2020] [Accepted: 02/26/2020] [Indexed: 12/20/2022]
Abstract
Fatty acids (FAs) are stored safely in the form of triacylglycerol (TAG) in lipid droplet (LD) organelles by professional storage cells called adipocytes. These lipids are mobilized during adipocyte lipolysis, the fundamental process of hydrolyzing TAG to FAs for internal or systemic energy use. Our understanding of adipocyte lipolysis has greatly increased over the past 50 years from a basic enzymatic process to a dynamic regulatory one, involving the assembly and disassembly of protein complexes on the surface of LDs. These dynamic interactions are regulated by hormonal signals such as catecholamines and insulin which have opposing effects on lipolysis. Upon stimulation, patatin-like phospholipase domain containing 2 (PNPLA2)/adipocyte triglyceride lipase (ATGL), the rate limiting enzyme for TAG hydrolysis, is activated by the interaction with its co-activator, alpha/beta hydrolase domain-containing protein 5 (ABHD5), which is normally bound to perilipin 1 (PLIN1). Recently identified negative regulators of lipolysis include G0/G1 switch gene 2 (G0S2) and PNPLA3 which interact with PNPLA2 and ABHD5, respectively. This review focuses on the dynamic protein-protein interactions involved in lipolysis and discusses some of the emerging concepts in the control of lipolysis that include allosteric regulation and protein turnover. Furthermore, recent research demonstrates that many of the proteins involved in adipocyte lipolysis are multifunctional enzymes and that lipolysis can mediate homeostatic metabolic signals at both the cellular and whole-body level to promote inter-organ communication. Finally, adipocyte lipolysis is involved in various diseases such as cancer, type 2 diabetes and fatty liver disease, and targeting adipocyte lipolysis is of therapeutic interest.
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12
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Dynamic changes in DICER levels in adipose tissue control metabolic adaptations to exercise. Proc Natl Acad Sci U S A 2020; 117:23932-23941. [PMID: 32900951 DOI: 10.1073/pnas.2011243117] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
DICER is a key enzyme in microRNA (miRNA) biogenesis. Here we show that aerobic exercise training up-regulates DICER in adipose tissue of mice and humans. This can be mimicked by infusion of serum from exercised mice into sedentary mice and depends on AMPK-mediated signaling in both muscle and adipocytes. Adipocyte DICER is required for whole-body metabolic adaptations to aerobic exercise training, in part, by allowing controlled substrate utilization in adipose tissue, which, in turn, supports skeletal muscle function. Exercise training increases overall miRNA expression in adipose tissue, and up-regulation of miR-203-3p limits glycolysis in adipose under conditions of metabolic stress. We propose that exercise training-induced DICER-miR-203-3p up-regulation in adipocytes is a key adaptive response that coordinates signals from working muscle to promote whole-body metabolic adaptations.
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13
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Kintscher U, Foryst-Ludwig A, Haemmerle G, Zechner R. The Role of Adipose Triglyceride Lipase and Cytosolic Lipolysis in Cardiac Function and Heart Failure. CELL REPORTS MEDICINE 2020; 1:100001. [PMID: 33205054 PMCID: PMC7659492 DOI: 10.1016/j.xcrm.2020.100001] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Heart failure is one of the leading causes of death worldwide. New therapeutic concepts are urgently required to lower the burden of heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF), the two major forms of heart failure. Lipolytic processes are induced during the development of heart failure and occur in adipose tissue and multiple organs, including the heart. Increasing evidence suggests that cellular lipolysis, in particular, adipose triglyceride lipase (ATGL) activity, has an important function in cardiac (patho)physiology. This review summarizes the crucial role of cellular lipolysis for normal cardiac function and for the development of HFrEF and HFpEF. We discuss the most relevant pre-clinical studies and elaborate on the cardiac consequences of non-myocardial and myocardial lipolysis modulation. Finally, we critically analyze the therapeutic importance of pharmacological ATGL inhibition as a potential treatment option for HFrEF and/or HFpEF in the future.
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Affiliation(s)
- Ulrich Kintscher
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Berlin, Germany
- Corresponding author
| | - Anna Foryst-Ludwig
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Berlin, Germany
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
- Einstein BIH Visiting Fellow, Berlin Institute of Health, and Charité - Universitätsmedizin Berlin, Berlin, Germany
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14
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Impact of skeletal muscle IL-6 on subcutaneous and visceral adipose tissue metabolism immediately after high- and moderate-intensity exercises. Pflugers Arch 2019; 472:217-233. [PMID: 31781893 DOI: 10.1007/s00424-019-02332-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/23/2019] [Accepted: 11/13/2019] [Indexed: 12/28/2022]
Abstract
White adipose tissue is a major energy reserve for the body and is essential for providing fatty acids for other tissues when needed. Skeletal muscle interleukin-6 (IL-6) has been shown to be secreted from the working muscle and has been suggested to signal to adipose tissue and enhance lipolysis. The aim of the present study was to investigate the role of skeletal muscle IL-6 in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) lipolysis and glyceroneogenesis with prolonged moderate-intensity exercise and high-intensity exercise in mice. Female inducible muscle-specific IL-6 knockout (IL-6 iMKO) mice and littermate control (Floxed) mice performed a single exercise bout for either 120 min at 16 m/min and 10° slope (moderate intensity) or 30 min at 20 m/min and 10° slope (high intensity), or they remained rested (rest). Visceral and subcutaneous adipose tissues, quadriceps muscles, and blood were quickly obtained. Plasma IL-6 increased in Floxed mice but not in IL-6 iMKO mice with high-intensity exercise. VAT signal transducer and activator of transcription (STAT)3Tyr705 phosphorylation was lower, and VAT hormone-sensitive lipase (HSL)Ser563 phosphorylation was higher in IL-6 iMKO mice than in Floxed mice at rest. Furthermore, HSLSer563 and HSLSer660 phosphorylation increased in VAT and phosphoenolpyruvate carboxykinase protein decreased in SAT with moderate-intensity exercise in both genotypes. On the other hand, both exercise protocols increased pyruvate dehydrogenaseSer232 phosphorylation in VAT only in IL-6 iMKO mice and decreased tumor necrosis factor-α messenger RNA in SAT and VAT only in Floxed mice. In conclusion, the present findings suggest that skeletal muscle IL-6 regulates markers of lipolysis in VAT in the basal state and pyruvate availability for glyceroneogenesis in VAT with exercise. Moreover, skeletal muscle IL-6 may contribute to exercise-induced anti-inflammatory effects in SAT and VAT.
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15
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Trites MJ, Clugston RD. The role of adipose triglyceride lipase in lipid and glucose homeostasis: lessons from transgenic mice. Lipids Health Dis 2019; 18:204. [PMID: 31757217 PMCID: PMC6874817 DOI: 10.1186/s12944-019-1151-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/07/2019] [Indexed: 12/14/2022] Open
Abstract
The ability of mammals to store and draw on fat reserves has been a driving force throughout evolution in an environment with intermittent nutrient availability. The discovery of adipose triglyceride lipase (ATGL) as a triglyceride lipase provided a heightened understanding of the mechanisms governing mobilization of fat reserves from adipose tissue. ATGL catalyses the initial step in adipose triglyceride lipolysis, working in concert with other enzymes to mobilize triglyceride for energy production. In addition to the role of ATGL in adipose tissue triglyceride mobilization, ATGL plays crucial roles in regulating lipid homeostasis in other tissues. These roles have been characterized primarily using transgenic mice with tissue-specific ATGL ablation. For example, the global ATGL knockout induces a severe cardiac defect that results in premature mortality that is mimicked by inducible cardiomyocyte-specific ATGL knockout. Global- and adipose-specific ATGL ablation induces a whole-body shift from lipid metabolism to glucose metabolism to satisfy metabolic demand primarily facilitated by an increase in glucose uptake by skeletal muscle. Generation of liver-specific ATGL knockouts has implicated hepatic lipolysis as a critical component of normal liver function. Analysis of β-cell ATGL knockouts implicates the necessity of pancreatic ATGL in insulin secretion. The objective of this review is to discuss the contributions of ATGL to systemic lipid- and glucose-homeostasis discovered through the study of transgenic mice.
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Affiliation(s)
- Michael J Trites
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada.,Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Robin D Clugston
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada. .,Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
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16
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Goossens C, Weckx R, Derde S, Dufour T, Vander Perre S, Pauwels L, Thiessen SE, Van Veldhoven PP, Van den Berghe G, Langouche L. Adipose tissue protects against sepsis-induced muscle weakness in mice: from lipolysis to ketones. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2019; 23:236. [PMID: 31262340 PMCID: PMC6600878 DOI: 10.1186/s13054-019-2506-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 06/04/2019] [Indexed: 02/07/2023]
Abstract
Background ICU-acquired weakness is a debilitating consequence of prolonged critical illness that is associated with poor outcome. Recently, premorbid obesity has been shown to protect against such illness-induced muscle wasting and weakness. Here, we hypothesized that this protection was due to increased lipid and ketone availability. Methods In a centrally catheterized, fluid-resuscitated, antibiotic-treated mouse model of prolonged sepsis, we compared markers of lipolysis and fatty acid oxidation in lean and obese septic mice (n = 117). Next, we compared markers of muscle wasting and weakness in septic obese wild-type and adipose tissue-specific ATGL knockout (AAKO) mice (n = 73), in lean septic mice receiving either intravenous infusion of lipids or standard parenteral nutrition (PN) (n = 70), and in lean septic mice receiving standard PN supplemented with either the ketone body 3-hydroxybutyrate or isocaloric glucose (n = 49). Results Obese septic mice had more pronounced lipolysis (p ≤ 0.05), peripheral fatty acid oxidation (p ≤ 0.05), and ketogenesis (p ≤ 0.05) than lean mice. Blocking lipolysis in obese septic mice caused severely reduced muscle mass (32% loss vs. 15% in wild-type, p < 0.001) and specific maximal muscle force (59% loss vs. 0% in wild-type; p < 0.001). In contrast, intravenous infusion of lipids in lean septic mice maintained specific maximal muscle force up to healthy control levels (p = 0.6), whereas this was reduced with 28% in septic mice receiving standard PN (p = 0.006). Muscle mass was evenly reduced with 29% in both lean septic groups (p < 0.001). Lipid administration enhanced fatty acid oxidation (p ≤ 0.05) and ketogenesis (p < 0.001), but caused unfavorable liver steatosis (p = 0.01) and a deranged lipid profile (p ≤ 0.01). Supplementation of standard PN with 3-hydroxybutyrate also attenuated specific maximal muscle force up to healthy control levels (p = 0.1), but loss of muscle mass could not be prevented (25% loss in both septic groups; p < 0.001). Importantly, this intervention improved muscle regeneration markers (p ≤ 0.05) without the unfavorable side effects seen with lipid infusion. Conclusions Obesity-induced muscle protection during sepsis is partly mediated by elevated mobilization and metabolism of endogenous fatty acids. Furthermore, increased availability of ketone bodies, either through ketogenesis or through parenteral infusion, appears to protect against sepsis-induced muscle weakness also in the lean. Electronic supplementary material The online version of this article (10.1186/s13054-019-2506-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chloë Goossens
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium
| | - Ruben Weckx
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium
| | - Sarah Derde
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium
| | - Thomas Dufour
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium
| | - Sarah Vander Perre
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium
| | - Lies Pauwels
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium
| | - Steven E Thiessen
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium
| | - Paul P Van Veldhoven
- Laboratory for Lipid Biochemistry and Protein Interactions, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium
| | - Greet Van den Berghe
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium
| | - Lies Langouche
- Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium.
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17
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Riis S, Christensen B, Nellemann B, Møller AB, Husted AS, Pedersen SB, Schwartz TW, Jørgensen JOL, Jessen N. Molecular adaptations in human subcutaneous adipose tissue after ten weeks of endurance exercise training in healthy males. J Appl Physiol (1985) 2018; 126:569-577. [PMID: 30571288 DOI: 10.1152/japplphysiol.00989.2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Endurance exercise training induces adaptations in metabolically active organs, but adaptations in human subcutaneous adipose tissue (scAT) remains incompletely understood. On the basis of animal studies, we hypothesized that endurance exercise training would increase the expression of proteins involved in lipolysis and glucose uptake in scAT. To test these hypotheses, 19 young and healthy males were randomized to either endurance exercise training (TR; age 18-24 yr; BMI 19.0-25.4 kg/m2) or a nonexercising control group (CON; age 21-35 yr; BMI 20.5-28.8 kg/m2). Abdominal subcutaneous fat biopsies and blood were obtained at rest before and after intervention. By using Western blotting and PCR, we determined expression of lipid droplet-associated proteins, various proteins involved in substrate metabolism, and mRNA abundance of cell surface G protein-coupled receptors (GPCRs). Adipose tissue insulin sensitivity was determined from fasting plasma insulin and nonesterified fatty acids (adipose tissue insulin resistance index; Adipo-IR). Adipo-IR improved in TR compared with CON ( P = 0.03). This was accompanied by increased insulin receptor (IR) protein expression in scAT with a 1.54-fold (SD 0.79) change from baseline in TR vs. 0.85 (SD 0.30) in CON ( P = 0.007). Additionally, hexokinase II (HKII) and succinate dehydrogenase complex subunit A (SDHA) protein increased in TR compared with CON ( P = 0.006 and P = 0.04, respectively). We did not observe changes in lipid droplet-associated proteins or mRNA abundance of GPCRs. Collectively, 10 weeks of endurance exercise training improved adipose tissue insulin sensitivity, which was accompanied by increased IR, HKII, and SDHA protein expression in scAT. We suggest that these adaptations contribute to an improved metabolic flexibility. NEW & NOTEWORTHY This study is the first to investigate the molecular adaptations in human subcutaneous adipose tissue (scAT) after endurance exercise training compared with a nonexercising control group. We show that endurance exercise training improves insulin sensitivity in human scAT, and this is accompanied by increased expression of insulin receptor, hexokinase II, and succinate dehydrogenase complex subunit A. Collectively, our data suggest that endurance exercise training induces molecular adaptations in human scAT, which may contribute to an improved metabolic flexibility.
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Affiliation(s)
- Simon Riis
- Section for Sport Science, Department of Public Health, Aarhus University , Aarhus , Denmark.,Research Laboratory for Biochemical Pathology, Department of Clinical Medicine, Aarhus University , Aarhus , Denmark
| | - Britt Christensen
- Section for Sport Science, Department of Public Health, Aarhus University , Aarhus , Denmark.,Department of Endocrinology and Internal Medicine, Aarhus University Hospital , Aarhus , Denmark
| | - Birgitte Nellemann
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital , Aarhus , Denmark
| | - Andreas Buch Møller
- Research Laboratory for Biochemical Pathology, Department of Clinical Medicine, Aarhus University , Aarhus , Denmark.,Steno Diabetes Center Aarhus, Aarhus University Hospital , Aarhus , Denmark
| | - Anna Sofie Husted
- Section for Metabolic Receptology, Novo Nordisk Foundation Center for Basic Metabolic Research , Copenhagen , Denmark
| | - Steen B Pedersen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital , Aarhus , Denmark
| | - Thue W Schwartz
- Section for Metabolic Receptology, Novo Nordisk Foundation Center for Basic Metabolic Research , Copenhagen , Denmark.,Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, University of Copenhagen , Copenhagen , Denmark
| | | | - Niels Jessen
- Research Laboratory for Biochemical Pathology, Department of Clinical Medicine, Aarhus University , Aarhus , Denmark.,Department of Biomedicine, Aarhus University , Aarhus , Denmark.,Steno Diabetes Center Aarhus, Aarhus University Hospital , Aarhus , Denmark
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18
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Ma S, Huang Q, Tominaga T, Liu C, Suzuki K. An 8-Week Ketogenic Diet Alternated Interleukin-6, Ketolytic and Lipolytic Gene Expression, and Enhanced Exercise Capacity in Mice. Nutrients 2018; 10:E1696. [PMID: 30405021 PMCID: PMC6266160 DOI: 10.3390/nu10111696] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/01/2018] [Accepted: 11/03/2018] [Indexed: 01/04/2023] Open
Abstract
Adjusting dietary fat intake is reported to affect mitochondrial biogenesis and fatty acid oxidation (FAO), and thus may enhance exercise capacity. However, a high-fat diet where carbohydrate intake is not limited enough also makes it difficult for athletes to maintain weight, and may fail to force the body to utilize fat. As such, a low-carbohydrate, high-fat, ketogenic diet (KD) may be viable. We have previously reported that an eight-week KD enhances exercise capacity, and suggested the mechanism to be enhanced lipolysis and ketolysis. In the present study, we investigated how an eight-week KD alters mRNA expression during fatty acid mobilization, FAO and ketolysis. We found that an eight-week KD may remodel the lipid metabolism profile, thus contributing to influence exercise capacity. We also found that ketolysis, lipolysis and FAO adaptations may contribute to enhanced exhaustive exercise performance. Along with enhanced FAO capacity during exhaustive exercise, a KD may also alter IL-6 synthesis and secretion profile, thus contribute to fatty acid mobilization, ketolysis, lipolysis and preventing muscle damage. Both the lipid metabolism response and IL-6 secretion appeared to be muscle fiber specific. Taken together, the previous and present results reveal that an eight-week KD may enhance exercise performance by up-regulating ketolysis and FAO ability. Therefore, a KD may have the potential to prevent muscle damage by altering IL-6 secretion profile, indicating that a KD may be a promising dietary approach in endurance athletes, sports, and for injury prevention.
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Affiliation(s)
- Sihui Ma
- Graduate School of Sport Sciences, Waseda University, Tokorozawa 359-1192, Japan.
| | - Qingyi Huang
- Graduate School of Sport Sciences, Waseda University, Tokorozawa 359-1192, Japan.
- College of Food Science, South China Agricultural University, Guangzhou 510642, China.
- The Key Laboratory of Food Quality and Safety of Guangdong Province, Guangzhou 510642, China.
| | - Takaki Tominaga
- College of Food Science, South China Agricultural University, Guangzhou 510642, China.
| | - Chunhong Liu
- College of Food Science, South China Agricultural University, Guangzhou 510642, China.
- The Key Laboratory of Food Quality and Safety of Guangdong Province, Guangzhou 510642, China.
| | - Katsuhiko Suzuki
- Faculty of Sport Sciences, Waseda University, Tokorozawa 359-1192, Japan.
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19
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Of mice and men: The physiological role of adipose triglyceride lipase (ATGL). Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:880-899. [PMID: 30367950 PMCID: PMC6439276 DOI: 10.1016/j.bbalip.2018.10.008] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 12/12/2022]
Abstract
Adipose triglyceride lipase (ATGL) has been discovered 14 years ago and revised our view on intracellular triglyceride (TG) mobilization – a process termed lipolysis. ATGL initiates the hydrolysis of TGs to release fatty acids (FAs) that are crucial energy substrates, precursors for the synthesis of membrane lipids, and ligands of nuclear receptors. Thus, ATGL is a key enzyme in whole-body energy homeostasis. In this review, we give an update on how ATGL is regulated on the transcriptional and post-transcriptional level and how this affects the enzymes' activity in the context of neutral lipid catabolism. In depth, we highlight and discuss the numerous physiological functions of ATGL in lipid and energy metabolism. Over more than a decade, different genetic mouse models lacking or overexpressing ATGL in a cell- or tissue-specific manner have been generated and characterized. Moreover, pharmacological studies became available due to the development of a specific murine ATGL inhibitor (Atglistatin®). The identification of patients with mutations in the human gene encoding ATGL and their disease spectrum has underpinned the importance of ATGL in humans. Together, mouse models and human data have advanced our understanding of the physiological role of ATGL in lipid and energy metabolism in adipose and non-adipose tissues, and of the pathophysiological consequences of ATGL dysfunction in mice and men. Summary of mouse models with genetic or pharmacological manipulation of ATGL. Summary of patients with mutations in the human gene encoding ATGL. In depth discussion of the role of ATGL in numerous physiological processes in mice and men.
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20
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Matoba K, Lu Y, Zhang R, Chen ER, Sangwung P, Wang B, Prosdocimo DA, Jain MK. Adipose KLF15 Controls Lipid Handling to Adapt to Nutrient Availability. Cell Rep 2018; 21:3129-3140. [PMID: 29241541 DOI: 10.1016/j.celrep.2017.11.032] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 10/13/2017] [Accepted: 11/09/2017] [Indexed: 12/24/2022] Open
Abstract
Adipose tissue stores energy in the form of triglycerides. The ability to regulate triglyceride synthesis and breakdown based on nutrient status (e.g., fed versus fasted) is critical for physiological homeostasis and dysregulation of this process can contribute to metabolic disease. Whereas much is known about hormonal control of this cycle, transcriptional regulation is not well understood. Here, we show that the transcription factor Kruppel-like factor 15 (KLF15) is critical for the control of adipocyte lipid turnover. Mice lacking Klf15 in adipose tissue (AK15KO) display decreased adiposity and are protected from diet-induced obesity. Mechanistic studies suggest that adipose KLF15 regulates key genes of triglyceride synthesis and inhibits lipolytic action, thereby promoting lipid storage in an insulin-dependent manner. Finally, AK15KO mice demonstrate accelerated lipolysis and altered systemic energetics (e.g., locomotion, ketogenesis) during fasting conditions. Our study identifies adipose KLF15 as an essential regulator of adipocyte lipid metabolism and systemic energy balance.
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Affiliation(s)
- Keiichiro Matoba
- Case Cardiovascular Research Institute, Department of Medicine, Case Western Reserve University School of Medicine, Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, USA; Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo 105-8461, Japan
| | - Yuan Lu
- Case Cardiovascular Research Institute, Department of Medicine, Case Western Reserve University School of Medicine, Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, USA
| | - Rongli Zhang
- Case Cardiovascular Research Institute, Department of Medicine, Case Western Reserve University School of Medicine, Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, USA
| | - Eric R Chen
- Case Cardiovascular Research Institute, Department of Medicine, Case Western Reserve University School of Medicine, Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, USA
| | - Panjamaporn Sangwung
- Case Cardiovascular Research Institute, Department of Medicine, Case Western Reserve University School of Medicine, Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, USA; Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Benlian Wang
- Center for Proteomics and Bioinformatics and Department of Nutrition, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Domenick A Prosdocimo
- Case Cardiovascular Research Institute, Department of Medicine, Case Western Reserve University School of Medicine, Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, USA
| | - Mukesh K Jain
- Case Cardiovascular Research Institute, Department of Medicine, Case Western Reserve University School of Medicine, Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, USA.
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21
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Parajuli N, Takahara S, Matsumura N, Kim TT, Ferdaoussi M, Migglautsch AK, Zechner R, Breinbauer R, Kershaw EE, Dyck JRB. Atglistatin ameliorates functional decline in heart failure via adipocyte-specific inhibition of adipose triglyceride lipase. Am J Physiol Heart Circ Physiol 2018; 315:H879-H884. [PMID: 29932770 DOI: 10.1152/ajpheart.00308.2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Despite advancements in therapies for cardiovascular disease and heart failure (HF), the incidence and prevalence of HF are increasing. Previous work has suggested that inhibiting adipose triglyceride lipase (ATGL) in adipose tissue during HF development may assist in the treatment of HF. The ability to specifically target the adipocyte as a potential treatment for HF is a novel approach that could significantly influence the management of HF in the future. Our objectives were to assess the cardiac structural and functional effects of pharmacological inhibition of ATGL in mice with HF, to assess whether ATGL inhibition works in an adipocyte-autonomous manner, and to determine the role that adiposity and glucose homeostasis play in this HF treatment approach. Using a known ATGL inhibitor, atglistatin, as well as mice with germline deletion of adipocyte-specific ATGL, we tested the effectiveness of ATGL inhibition in mice with pressure overload-induced HF. Here, we show that atglistatin can prevent the functional decline in HF and provide evidence that specifically targeting ATGL in the adipocyte is sufficient to prevent worsening of HF. We further demonstrate that the benefit resulting from atglistatin in HF is not dependent on previously suggested improvements in glucose homeostasis, nor are the benefits derived from increased adiposity. Overall, the results of this study suggest that adipocyte-specific pharmacological inhibition of ATGL may represent a novel therapeutic option for HF. NEW & NOTEWORTHY This work shows for the first time that the adipose triglyceride lipase (ATGL)-specific inhibitor atglistatin can prevent worsening heart failure. Furthermore, using mice with adipocyte-specific ATGL ablation, this study demonstrates that ATGL inhibition works in an adipocyte-autonomous manner to ameliorate a functional decline in heart failure. Overall, this work demonstrates that specifically targeting the adipocyte to inhibit ATGL is a potential treatment for heart failure.
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Affiliation(s)
- Nirmal Parajuli
- Cardiovascular Research Centre, Mazankowski Alberta Heart Institute, and Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta , Edmonton, Alberta , Canada.,Division of Basic Biomedical Science, University of South Dakota, Vermillion, South Dakota
| | - Shingo Takahara
- Cardiovascular Research Centre, Mazankowski Alberta Heart Institute, and Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta , Edmonton, Alberta , Canada.,Division of Cardiovascular Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi , Japan
| | - Nobutoshi Matsumura
- Cardiovascular Research Centre, Mazankowski Alberta Heart Institute, and Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta , Edmonton, Alberta , Canada.,Division of Cardiovascular Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi , Japan
| | - Ty T Kim
- Cardiovascular Research Centre, Mazankowski Alberta Heart Institute, and Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta , Edmonton, Alberta , Canada
| | - Mourad Ferdaoussi
- Cardiovascular Research Centre, Mazankowski Alberta Heart Institute, and Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta , Edmonton, Alberta , Canada
| | - Anna K Migglautsch
- Institute of Organic Chemistry, Graz University of Technology , Graz , Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz , Graz , Austria
| | - Rolf Breinbauer
- Institute of Organic Chemistry, Graz University of Technology , Graz , Austria
| | - Erin E Kershaw
- Division of Endocrinology and Metabolism, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Jason R B Dyck
- Cardiovascular Research Centre, Mazankowski Alberta Heart Institute, and Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta , Edmonton, Alberta , Canada
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22
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Whytock KL, Shepherd SO, Wagenmakers AJM, Strauss JA. Hormone-sensitive lipase preferentially redistributes to lipid droplets associated with perilipin-5 in human skeletal muscle during moderate-intensity exercise. J Physiol 2018. [PMID: 29527681 DOI: 10.1113/jp275502] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
KEY POINTS Hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) are the key enzymes involved in intramuscular triglyceride (IMTG) lipolysis. In isolated rat skeletal muscle, HSL translocates to IMTG-containing lipid droplets (LDs) following electrical stimulation, but whether HSL translocation occurs in human skeletal muscle during moderate-intensity exercise is currently unknown. Perilipin-2 (PLIN2) and perilipin-5 (PLIN5) proteins have been implicated in regulating IMTG lipolysis by interacting with HSL and ATGL in cell culture and rat skeletal muscle studies. This study investigated the hypothesis that HSL (but not ATGL) redistributes to LDs during moderate-intensity exercise in human skeletal muscle, and whether the localisation of these lipases with LDs was affected by the presence of PLIN proteins on the LDs. HSL preferentially redistributed to PLIN5-associated LDs whereas ATGL distribution was not altered with exercise; this is the first study to illustrate the pivotal step of HSL redistribution to PLIN5-associated LDs following moderate-intensity exercise in human skeletal muscle. ABSTRACT Hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) control skeletal muscle lipolysis. ATGL is present on the surface of lipid droplets (LDs) containing intramuscular triglyceride (IMTG) in both the basal state and during exercise. HSL translocates to LD in ex vivo electrically stimulated rat skeletal muscle. Perilipin-2- and perilipin-5-associated lipid droplets (PLIN2+ and PLIN5+ LDs) are preferentially depleted during exercise in humans, indicating that these PLINs may control muscle lipolysis. We aimed to test the hypothesis that in human skeletal muscle in vivo HSL (but not ATGL) is redistributed to PLIN2+ and PLIN5+ LDs during moderate-intensity exercise. Muscle biopsies from 8 lean trained males (age 21 ± 1 years, BMI 22.6 ± 1.2 kg m-2 and V̇O2 peak 48.2 ± 5.0 ml min-1 kg-1 ) were obtained before and immediately following 60 min of cycling exercise at ∼59% V̇O2 peak . Cryosections were stained using antibodies targeting ATGL, HSL, PLIN2 and PLIN5. LDs were stained using BODIPY 493/503. Images were obtained using confocal immunofluorescence microscopy and object-based colocalisation analyses were performed. Following exercise, HSL colocalisation to LDs increased (P < 0.05), and was significantly greater to PLIN5+ LDs (+53%) than to PLIN5- LDs (+34%) (P < 0.05), while the increases in HSL colocalisation to PLIN2+ LDs (+16%) and PLIN2- LDs (+28%) were not significantly different. Following exercise, the fraction of LDs colocalised with ATGL (0.53 ± 0.04) did not significantly change (P < 0.05) and was not affected by PLIN association to the LDs. This study presents the first evidence of exercise-induced HSL redistribution to LDs in human skeletal muscle and identifies PLIN5 as a facilitator of this mechanism.
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Affiliation(s)
- Katie L Whytock
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK
| | - Sam O Shepherd
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK
| | - Anton J M Wagenmakers
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK
| | - Juliette A Strauss
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK
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23
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Peppler WT, Townsend LK, Knuth CM, Foster MT, Wright DC. Subcutaneous inguinal white adipose tissue is responsive to, but dispensable for, the metabolic health benefits of exercise. Am J Physiol Endocrinol Metab 2018; 314:E66-E77. [PMID: 28978546 PMCID: PMC5866388 DOI: 10.1152/ajpendo.00226.2017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Exercise training has robust effects on subcutaneous inguinal white adipose tissue (iWAT), characterized by a shift to a brown adipose tissue (BAT)-like phenotype. Consistent with this, transplantation of exercise-trained iWAT into sedentary rodents activates thermogenesis and improves glucose homeostasis, suggesting that iWAT metabolism may contribute to the beneficial effects of exercise. However, it is yet to be determined if adaptations in iWAT are necessary for the beneficial systemic effects of exercise. To test this, male C57BL/6 mice were provided access to voluntary wheel running (VWR) or remained as a cage control (SED) for 11 nights after iWAT removal via lipectomy (LIPX) or SHAM surgery. We found that SHAM and LIPX mice with access to VWR ran similar distances and had comparable reductions in body mass, increased food intake, and increased respiratory exchange ratio (RER). Further, VWR improved indexes of glucose homeostasis and insulin tolerance in both SHAM and LIPX mice. The lack of effect of LIPX in the response to VWR was not explained by compensatory increases in markers of mitochondrial biogenesis and thermogenesis in skeletal muscle, epididymal white adipose tissue, or interscapular brown adipose tissue. Together, these data demonstrate that mice with and without iWAT have comparable adaptations to VWR, suggesting that iWAT may be dispensable for the metabolic health benefits of exercise.
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Affiliation(s)
- Willem T Peppler
- Department of Human Health and Nutritional Sciences, University of Guelph , Guelph, Ontario , Canada
| | - Logan K Townsend
- Department of Human Health and Nutritional Sciences, University of Guelph , Guelph, Ontario , Canada
| | - Carly M Knuth
- Department of Human Health and Nutritional Sciences, University of Guelph , Guelph, Ontario , Canada
| | - Michelle T Foster
- Department of Food Science and Human Nutrition, Colorado State University , Fort Collins, Colorado
| | - David C Wright
- Department of Human Health and Nutritional Sciences, University of Guelph , Guelph, Ontario , Canada
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24
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Watt MJ, Cheng Y. Triglyceride metabolism in exercising muscle. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1250-1259. [PMID: 28652193 DOI: 10.1016/j.bbalip.2017.06.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 06/15/2017] [Accepted: 06/20/2017] [Indexed: 12/21/2022]
Abstract
Triglycerides are stored within lipid droplets in skeletal muscle and can be hydrolyzed to produce fatty acids for energy production through β-oxidation and oxidative phosphorylation. While there was some controversy regarding the quantitative importance of intramyocellular triglyceride (IMTG) as a metabolic substrate, recent advances in proton magnetic resonance spectroscopy and confocal microscopy support earlier tracer and biopsy studies demonstrating a substantial contribution of IMTG to energy production, particularly during moderate-intensity endurance exercise. This review provides an update on the understanding of IMTG utilization during exercise, with a focus on describing the key regulatory proteins that control IMTG breakdown and how these proteins respond to acute exercise and in the adaptation to exercise training. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
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Affiliation(s)
- Matthew J Watt
- Metabolic Disease and Obesity program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia; Department of Physiology, Monash University, Clayton, Victoria 3800, Australia.
| | - Yunsheng Cheng
- Metabolic Disease and Obesity program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia; Department of Physiology, Monash University, Clayton, Victoria 3800, Australia
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25
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Goodpaster BH, Sparks LM. Metabolic Flexibility in Health and Disease. Cell Metab 2017; 25:1027-1036. [PMID: 28467922 PMCID: PMC5513193 DOI: 10.1016/j.cmet.2017.04.015] [Citation(s) in RCA: 510] [Impact Index Per Article: 72.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 04/07/2017] [Accepted: 04/14/2017] [Indexed: 02/07/2023]
Abstract
Metabolic flexibility is the ability to respond or adapt to conditional changes in metabolic demand. This broad concept has been propagated to explain insulin resistance and mechanisms governing fuel selection between glucose and fatty acids, highlighting the metabolic inflexibility of obesity and type 2 diabetes. In parallel, contemporary exercise physiology research has helped to identify potential mechanisms underlying altered fuel metabolism in obesity and diabetes. Advances in "omics" technologies have further stimulated additional basic and clinical-translational research to further interrogate mechanisms for improved metabolic flexibility in skeletal muscle and adipose tissue with the goal of preventing and treating metabolic disease.
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Affiliation(s)
- Bret H Goodpaster
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Sanford Burnham Prebys Medical Discovery Institute, 301 East Princeton Street, Orlando, FL 32804, USA.
| | - Lauren M Sparks
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Sanford Burnham Prebys Medical Discovery Institute, 301 East Princeton Street, Orlando, FL 32804, USA
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26
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Laurens C, Moro C. Intramyocellular fat storage in metabolic diseases. Horm Mol Biol Clin Investig 2017; 26:43-52. [PMID: 26741351 DOI: 10.1515/hmbci-2015-0045] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 11/18/2015] [Indexed: 12/13/2022]
Abstract
Over the past decades, obesity and its metabolic co-morbidities such as type 2 diabetes (T2D) developed to reach an endemic scale. However, the mechanisms leading to the development of T2D are still poorly understood. One main predictor for T2D seems to be lipid accumulation in "non-adipose" tissues, best known as ectopic lipid storage. A growing body of data suggests that these lipids may play a role in impairing insulin action in metabolic tissues, such as liver and skeletal muscle. This review aims to discuss recent literature linking ectopic lipid storage and insulin resistance, with emphasis on lipid deposition in skeletal muscle. The link between skeletal muscle lipid content and insulin sensitivity, as well as the mechanisms of lipid-induced insulin resistance and potential therapeutic strategies to alleviate lipotoxic lipid pressure in skeletal muscle will be discussed.
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27
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Fujikawa T, Castorena CM, Pearson M, Kusminski CM, Ahmed N, Battiprolu PK, Kim KW, Lee S, Hill JA, Scherer PE, Holland WL, Elmquist JK. SF-1 expression in the hypothalamus is required for beneficial metabolic effects of exercise. eLife 2016; 5. [PMID: 27874828 PMCID: PMC5119890 DOI: 10.7554/elife.18206] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 11/14/2016] [Indexed: 12/31/2022] Open
Abstract
Exercise has numerous beneficial metabolic effects. The central nervous system (CNS) is critical for regulating energy balance and coordinating whole body metabolism. However, a role for the CNS in the regulation of metabolism in the context of the exercise remains less clear. Here, using genetically engineered mice we assessed the requirement of steroidogenic factor-1 (SF-1) expression in neurons of the ventromedial hypothalamic nucleus (VMH) in mediating the beneficial effects of exercise on metabolism. We found that VMH-specific deletion of SF-1 blunts (a) the reductions in fat mass, (b) improvements in glycemia, and (c) increases in energy expenditure that are associated with exercise training. Unexpectedly, we found that SF-1 deletion in the VMH attenuates metabolic responses of skeletal muscle to exercise, including induction of PGC-1α expression. Collectively, this evidence suggests that SF-1 expression in VMH neurons is required for the beneficial effects of exercise on metabolism.
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Affiliation(s)
- Teppei Fujikawa
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Carlos M Castorena
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Mackenzie Pearson
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Christine M Kusminski
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Newaz Ahmed
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Pavan K Battiprolu
- Department of Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Ki Woo Kim
- Department of Pharmacology, Wonju College of Medicine, Yonsei University, Wonju, South Korea.,Department of Global Medical Science, Wonju College of Medicine, Yonsei University, Wonju, South Korea.,Institute of Lifestyle Medicine and Nuclear Receptor Research Consortium, Wonju College of Medicine, Yonsei University, Wonju, South Korea
| | - Syann Lee
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joseph A Hill
- Department of Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, United States
| | - William L Holland
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joel K Elmquist
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States.,Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States
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28
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Fujikawa T, Castorena CM, Pearson M, Kusminski CM, Ahmed N, Battiprolu PK, Kim KW, Lee S, Hill JA, Scherer PE, Holland WL, Elmquist JK. SF-1 expression in the hypothalamus is required for beneficial metabolic effects of exercise. eLife 2016; 5:e18206. [PMID: 27874828 DOI: 10.7554/elife.15092.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 11/14/2016] [Indexed: 05/26/2023] Open
Abstract
Exercise has numerous beneficial metabolic effects. The central nervous system (CNS) is critical for regulating energy balance and coordinating whole body metabolism. However, a role for the CNS in the regulation of metabolism in the context of the exercise remains less clear. Here, using genetically engineered mice we assessed the requirement of steroidogenic factor-1 (SF-1) expression in neurons of the ventromedial hypothalamic nucleus (VMH) in mediating the beneficial effects of exercise on metabolism. We found that VMH-specific deletion of SF-1 blunts (a) the reductions in fat mass, (b) improvements in glycemia, and (c) increases in energy expenditure that are associated with exercise training. Unexpectedly, we found that SF-1 deletion in the VMH attenuates metabolic responses of skeletal muscle to exercise, including induction of PGC-1α expression. Collectively, this evidence suggests that SF-1 expression in VMH neurons is required for the beneficial effects of exercise on metabolism.
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Affiliation(s)
- Teppei Fujikawa
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Carlos M Castorena
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Mackenzie Pearson
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Christine M Kusminski
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Newaz Ahmed
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Pavan K Battiprolu
- Department of Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Ki Woo Kim
- Department of Pharmacology, Wonju College of Medicine, Yonsei University, Wonju, South Korea
- Department of Global Medical Science, Wonju College of Medicine, Yonsei University, Wonju, South Korea
- Institute of Lifestyle Medicine and Nuclear Receptor Research Consortium, Wonju College of Medicine, Yonsei University, Wonju, South Korea
| | - Syann Lee
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joseph A Hill
- Department of Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, United States
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, United States
| | - William L Holland
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joel K Elmquist
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, United States
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States
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29
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Biswas D, Ghosh M, Kumar S, Chakrabarti P. PPARα-ATGL pathway improves muscle mitochondrial metabolism: implication in aging. FASEB J 2016; 30:3822-3834. [PMID: 27485820 DOI: 10.1096/fj.201600571rr] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/27/2016] [Indexed: 02/05/2023]
Abstract
Adipose triglyceride lipase (ATGL) maintains an optimum mitochondrial function putatively by generating cognate ligands for peroxisome proliferator-activated receptor α (PPARα), which, together with PPARγ coactivator-1α (PGC1α), regulate muscle mitochondrial biogenesis. However, the cross-talk between ATGL and PPARα in skeletal muscle mitochondrial metabolism and its implication in chronological aging is poorly understood. The role of ATGL in muscle mitochondrial metabolism was studied by overexpressing and depleting the gene and studying its downstream effect in cultured myotubes and in murine skeletal muscle. We found that PPARα directly induces ATGL expression during myogenesis. Overexpression of ATGL significantly enhanced while depletion of ATGL attenuated mitochondrial oxidative phosphorylation and fatty acid oxidation without alteration in mitochondrial content, and it rendered PPARα and PGC1α redundant in promoting mitochondrial oxidative function. However, ATGL did not alter PPARα-dependent lipid accumulation and insulin sensitivity. In middle-aged rats, ATGL expression was higher and correlated with PPARα expression and sustained fatty acid oxidation in oxidative soleus muscle. Fenofibrate feeding further induced ATGL expression selectively in this muscle compartment. These findings illustrate that PPARα and ATGL constitute a regulatory pathway in skeletal muscle, suggesting their role as a mitochondrial metabolic reserve.-Biswas, D., Ghosh, M., Kumar, S., Chakrabarti, P. PPARα-ATGL pathway improves muscle mitochondrial metabolism: implication in aging.
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Affiliation(s)
- Dipsikha Biswas
- Division of Cell Biology and Physiology, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, India; and
| | - Mainak Ghosh
- Division of Cell Biology and Physiology, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, India; and
| | - Subhankar Kumar
- Department of Physiology, Institute of Postgraduate Medical Education and Research, Kolkata, India
| | - Partha Chakrabarti
- Division of Cell Biology and Physiology, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, India; and
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