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Fuwa M, Kajita K, Mori I, Asano M, Kajita T, Senda T, Inagaki T, Morita H. Mitochondrial fractions located in the cytoplasmic and peridroplet areas of white adipocytes have distinct roles. FEBS Lett 2024. [PMID: 38658180 DOI: 10.1002/1873-3468.14877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 03/12/2024] [Indexed: 04/26/2024]
Abstract
The role of mitochondria in white adipocytes (WAs) has not been fully explored. A recent study revealed that brown adipocytes contain functionally distinct mitochondrial fractions, cytoplasmic mitochondria, and peridroplet mitochondria. However, it is not known whether such a functional division of mitochondria exists in WA. Herein, we observed that mitochondria could be imaged and mitochondrial DNA and protein detected in pellets obtained from the cytoplasmic layer and oil layer of WAs after centrifugation. The mitochondria in each fraction were designated as cytoplasmic mitochondria (CMw) and peridroplet mitochondria (PDMw) in WAs, respectively. CMw had higher β-oxidation activity than PDMw, and PDMw was associated with diacylglycerol acyltransferase 2. Therefore, CMw may be involved in β-oxidation and PDMw in droplet expansion in WAs.
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Affiliation(s)
- Masayuki Fuwa
- Department of General Internal Medicine, Gifu University Graduate School of Medicine, Japan
| | - Kazuo Kajita
- Department of Health and Nutrition, Faculty of Home Economics, Gifu Women's University, Japan
| | - Ichiro Mori
- Department of General Internal Medicine, Gifu University Graduate School of Medicine, Japan
| | - Motochika Asano
- Department of General Internal Medicine, Gifu University Graduate School of Medicine, Japan
| | - Toshiko Kajita
- Department of General Internal Medicine, Gifu University Graduate School of Medicine, Japan
| | - Takao Senda
- Department of Anatomy, Gifu University Graduate School of Medicine, Japan
| | - Takeshi Inagaki
- Laboratory of Epigenetics and Metabolism, Institute for Molecular and Cellular Regulation, Gunnma University, Maebashi-shi, Japan
| | - Hiroyuki Morita
- Department of General Internal Medicine, Gifu University Graduate School of Medicine, Japan
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2
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Guo Y, Abou Daya F, Le HD, Panda S, Melkani GC. Diurnal expression of Dgat2 induced by time-restricted feeding maintains cardiac health in the Drosophila model of circadian disruption. Aging Cell 2024:e14169. [PMID: 38616316 DOI: 10.1111/acel.14169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 03/20/2024] [Accepted: 03/22/2024] [Indexed: 04/16/2024] Open
Abstract
Circadian disruption is associated with an increased risk of cardiometabolic disorders and cardiac diseases. Time-restricted feeding/eating (TRF/TRE), restricting food intake within a consistent window of the day, has shown improvements in heart function from flies and mice to humans. However, whether and how TRF still conveys cardiac benefits in the context of circadian disruption remains unclear. Here, we demonstrate that TRF sustains cardiac performance, myofibrillar organization, and regulates cardiac lipid accumulation in Drosophila when the circadian rhythm is disrupted by constant light. TRF induces oscillations in the expression of genes associated with triglyceride metabolism. In particular, TRF induces diurnal expression of diacylglycerol O-acyltransferase 2 (Dgat2), peaking during the feeding period. Heart-specific manipulation of Dgat2 modulates cardiac function and lipid droplet accumulation. Strikingly, heart-specific overexpression of human Dgat2 at ZT 0-10 significantly improves cardiac performance in flies exposed to constant light. We have demonstrated that TRF effectively attenuates cardiac decline induced by circadian disruption. Moreover, our data suggests that diurnal expression of Dgat2 induced by TRF is beneficial for heart health under circadian disruption. Overall, our findings have underscored the relevance of TRF in preserving heart health under circadian disruptions and provided potential targets, such as Dgat2, and strategies for therapeutic interventions in mitigating cardiac aging, metabolic disorders, and cardiac diseases in humans.
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Affiliation(s)
- Yiming Guo
- Department of Pathology, Division of Molecular and Cellular Pathology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Farah Abou Daya
- Department of Pathology, Division of Molecular and Cellular Pathology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Hiep Dinh Le
- Regulatory Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, USA
| | - Satchidananda Panda
- Regulatory Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California, USA
| | - Girish C Melkani
- Department of Pathology, Division of Molecular and Cellular Pathology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Di Maio G, Alessio N, Ambrosino A, Al Sammarraie SHA, Monda M, Di Bernardo G. Irisin influences the in vitro differentiation of human mesenchymal stromal cells, promoting a tendency toward beiging adipogenesis. J Cell Biochem 2024. [PMID: 38591469 DOI: 10.1002/jcb.30565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 03/10/2024] [Accepted: 04/01/2024] [Indexed: 04/10/2024]
Abstract
Mammals exhibit two distinct types of adipose depots: white adipose tissue (WAT) and brown adipose tissue (BAT). While WAT primarily functions as a site for energy storage, BAT serves as a thermogenic tissue that utilizes energy and glucose consumption to regulate core body temperature. Under specific stimuli such as exercise, cold exposure, and drug treatment, white adipocytes possess a remarkable ability to undergo transdifferentiation into brown-like cells known as beige adipocytes. This transformation process, known as the "browning of WAT," leads to the acquisition of new morphological and physiological characteristics by white adipocytes. We investigated the potential role of Irisin, a 12 kDa myokine that is secreted in mice and humans by skeletal muscle after physical activity, in inducing the browning process in mesenchymal stromal cells (MSCs). A subset of the MSCs possesses the remarkable capability to differentiate into different cell types such as adipocytes, osteocytes, and chondrocytes. Consequently, comprehending the effects of Irisin on MSC biology becomes a crucial factor in investigating antiobesity medications. In our study, the primary objective is to evaluate the impact of Irisin on various cell types engaged in distinct stages of the differentiation process, including stem cells, committed precursors, and preadipocytes. By analyzing the effects of Irisin on these specific cell populations, our aim is to gain a comprehensive understanding of its influence throughout the entire differentiation process, rather than solely concentrating on the final differentiated cells. This approach enables us to obtain insights into the broader effects of Irisin on the cellular dynamics and mechanisms involved in adipogenesis.
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Affiliation(s)
- Girolamo Di Maio
- Human Physiology and Unit of Dietetic and Sports Medicine Section, Department of Experimental Medicine, School of Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Nicola Alessio
- Biotechnology and Molecular Biology Section, Department of Experimental Medicine, School of Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Alessia Ambrosino
- Biotechnology and Molecular Biology Section, Department of Experimental Medicine, School of Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Sura H A Al Sammarraie
- Biotechnology and Molecular Biology Section, Department of Experimental Medicine, School of Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Marcellino Monda
- Human Physiology and Unit of Dietetic and Sports Medicine Section, Department of Experimental Medicine, School of Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Giovanni Di Bernardo
- Biotechnology and Molecular Biology Section, Department of Experimental Medicine, School of Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
- Center for Biotechnology, Sbarro Institute for Cancer Research and Molecular Medicine, Temple University, Philadelphia, Pennsylvania, USA
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Sharma AK, Khandelwal R, Wolfrum C. Futile lipid cycling: from biochemistry to physiology. Nat Metab 2024:10.1038/s42255-024-01003-0. [PMID: 38459186 DOI: 10.1038/s42255-024-01003-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 02/02/2024] [Indexed: 03/10/2024]
Abstract
In the healthy state, the fat stored in our body isn't just inert. Rather, it is dynamically mobilized to maintain an adequate concentration of fatty acids (FAs) in our bloodstream. Our body tends to produce excess FAs to ensure that the FA availability is not limiting. The surplus FAs are actively re-esterified into glycerides, initiating a cycle of breakdown and resynthesis of glycerides. This cycle consumes energy without generating a new product and is commonly referred to as the 'futile lipid cycle' or the glyceride/FA cycle. Contrary to the notion that it's a wasteful process, it turns out this cycle is crucial for systemic metabolic homeostasis. It acts as a control point in intra-adipocyte and inter-organ cross-talk, a metabolic rheostat, an energy sensor and a lipid diversifying mechanism. In this Review, we discuss the metabolic regulation and physiological implications of the glyceride/FA cycle and its mechanistic underpinnings.
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Affiliation(s)
- Anand Kumar Sharma
- Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland.
| | - Radhika Khandelwal
- Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland
| | - Christian Wolfrum
- Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland.
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Bu SY. Role of Dgat2 in Glucose Uptake and Fatty Acid Metabolism in C2C12 Skeletal Myotubes. J Microbiol Biotechnol 2023; 33:1563-1575. [PMID: 37644753 PMCID: PMC10772559 DOI: 10.4014/jmb.2307.07018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 07/25/2023] [Accepted: 07/31/2023] [Indexed: 08/31/2023]
Abstract
Acyl-coenzyme A (CoA):diacylglycerol acyltransferase 2 (DGAT2) catalyzes the last stage of triacylglycerol (TAG) synthesis, a process that forms ester bonds with diacylglycerols (DAG) and fatty acyl-CoA substrates. The enzymatic role of Dgat2 has been studied in various biological species. Still, the full description of how Dgat2 channels fatty acids in skeletal myocytes and the consequence thereof in glucose uptake have yet to be well established. Therefore, this study explored the mediating role of Dgat2 in glucose uptake and fatty acid partitioning under short interfering ribonucleic acid (siRNA)-mediated Dgat2 knockdown conditions. Cells transfected with Dgat2 siRNA downregulated glucose transporter type 4 (Glut4) messenger RNA (mRNA) expression and decreased the cellular uptake of [1-14C]-labeled 2-deoxyglucose up to 24.3% (p < 0.05). Suppression of Dgat2 deteriorated insulininduced Akt phosphorylation. Dgat2 siRNA reduced [1-14C]-labeled oleic acid incorporation into TAG, but increased the level of [1-14C]-labeled free fatty acids at 3 h after initial fatty acid loading. In an experiment of chasing radioisotope-labeled fatty acids, Dgat2 suppression augmented the level of cellular free fatty acids. It decreased the level of re-esterification of free fatty acids to TAG by 67.6% during the chase period, and the remaining pulses of phospholipids and cholesteryl esters were decreased by 34.5% and 61%, respectively. Incorporating labeled fatty acids into beta-oxidation products increased in Dgat2 siRNA transfected cells without gene expression involving fatty acid oxidation. These results indicate that Dgat2 has regulatory function in glucose uptake, possibly through the reaction of TAG with endogenously released or recycled fatty acids.
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Affiliation(s)
- So Young Bu
- Department of Food and Nutrition, College of Engineering, Daegu University, Gyeongsan 38453, Republic of Korea
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Irshad Z, Lund J, Sillars A, Løvsletten NG, Gharanei S, Salt IP, Freeman DJ, Gill JMR, Thoresen GH, Rustan AC, Zammit VA. The roles of DGAT1 and DGAT2 in human myotubes are dependent on donor patho-physiological background. FASEB J 2023; 37:e23209. [PMID: 37779421 PMCID: PMC10947296 DOI: 10.1096/fj.202300960rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 09/01/2023] [Accepted: 09/06/2023] [Indexed: 10/03/2023]
Abstract
The roles of DGAT1 and DGAT2 in lipid metabolism and insulin responsiveness of human skeletal muscle were studied using cryosections and myotubes prepared from muscle biopsies from control, athlete, and impaired glucose regulation (IGR) cohorts of men. The previously observed increases in intramuscular triacylglycerol (IMTG) in athletes and IGR were shown to be related to an increase in lipid droplet (LD) area in type I fibers in athletes but, conversely, in type II fibers in IGR subjects. Specific inhibition of both diacylglycerol acyltransferase (DGAT) 1 and 2 decreased fatty acid (FA) uptake by myotubes, whereas only DGAT2 inhibition also decreased fatty acid oxidation. Fatty acid uptake in myotubes was negatively correlated with the lactate thresholds of the respective donors. DGAT2 inhibition lowered acetate uptake and oxidation in myotubes from all cohorts whereas DGAT1 inhibition had no effect. A positive correlation between acetate oxidation in myotubes and resting metabolic rate (RMR) from fatty acid oxidation in vivo was observed. Myotubes from athletes and IGR had higher rates of de novo lipogenesis from acetate that were normalized by DGAT2 inhibition. Moreover, DGAT2 inhibition in myotubes also resulted in increased insulin-induced Akt phosphorylation. The differential effects of DGAT1 and DGAT2 inhibition suggest that the specialized role of DGAT2 in esterifying nascent diacylglycerols and de novo synthesized FA is associated with synthesis of a pool of triacylglycerol, which upon hydrolysis results in effectors that promote mitochondrial fatty acid oxidation but decrease insulin signaling in skeletal muscle cells.
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Affiliation(s)
- Zehra Irshad
- Translational and Experimental Medicine, Warwick Medical SchoolUniversity of WarwickCoventryUK
| | - Jenny Lund
- Section for Pharmacology and Pharmaceutical Biosciences, Department of PharmacyUniversity of OsloOsloNorway
| | - Anne Sillars
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Nils Gunnar Løvsletten
- Section for Pharmacology and Pharmaceutical Biosciences, Department of PharmacyUniversity of OsloOsloNorway
| | - Seley Gharanei
- Translational and Experimental Medicine, Warwick Medical SchoolUniversity of WarwickCoventryUK
- Warwickshire Institute for the Study of Diabetes, Endocrinology and Metabolism (WISDEM)University Hospitals Coventry and Warwickshire NHS TrustCoventryUK
| | - Ian P. Salt
- School of Molecular Biosciences, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Dilys J. Freeman
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Jason M. R. Gill
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - G. Hege Thoresen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of PharmacyUniversity of OsloOsloNorway
- Department of Pharmacology, Institute of Clinical MedicineUniversity of OsloOsloNorway
| | - Arild C. Rustan
- Section for Pharmacology and Pharmaceutical Biosciences, Department of PharmacyUniversity of OsloOsloNorway
| | - Victor A. Zammit
- Translational and Experimental Medicine, Warwick Medical SchoolUniversity of WarwickCoventryUK
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Musso G, Saba F, Cassader M, Gambino R. Lipidomics in pathogenesis, progression and treatment of nonalcoholic steatohepatitis (NASH): Recent advances. Prog Lipid Res 2023; 91:101238. [PMID: 37244504 DOI: 10.1016/j.plipres.2023.101238] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 05/20/2023] [Accepted: 05/21/2023] [Indexed: 05/29/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease affecting up to 30% of the general adult population. NAFLD encompasses a histological spectrum ranging from pure steatosis to non-alcoholic steatohepatitis (NASH). NASH can progress to cirrhosis and is becoming the most common indication for liver transplantation, as a result of increasing disease prevalence and of the absence of approved treatments. Lipidomic readouts of liver blood and urine samples from experimental models and from NASH patients disclosed an abnormal lipid composition and metabolism. Collectively, these changes impair organelle function and promote cell damage, necro-inflammation and fibrosis, a condition termed lipotoxicity. We will discuss the lipid species and metabolic pathways leading to NASH development and progression to cirrhosis, as well as and those species that can contribute to inflammation resolution and fibrosis regression. We will also focus on emerging lipid-based therapeutic opportunities, including specialized proresolving lipid molecules and macrovesicles contributing to cell-to-cell communication and NASH pathophysiology.
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Affiliation(s)
- Giovanni Musso
- Dept of Emergency Medicine, San Luigi Gonzaga University Hospital, Orbassano, Turin, Italy.
| | - Francesca Saba
- Dept. of Medical Sciences, San Giovanni Battista Hospital, University of Turin, Turin, Italy
| | - Maurizio Cassader
- Dept. of Medical Sciences, San Giovanni Battista Hospital, University of Turin, Turin, Italy
| | - Roberto Gambino
- Dept. of Medical Sciences, San Giovanni Battista Hospital, University of Turin, Turin, Italy
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Adigun OA, Pham TH, Grapov D, Nadeem M, Jewell LE, Cheema M, Galagedara L, Thomas R. Phyto-oxylipin mediated plant immune response to colonization and infection in the soybean- Phytophthora sojae pathosystem. Front Plant Sci 2023; 14:1141823. [PMID: 37251755 PMCID: PMC10219219 DOI: 10.3389/fpls.2023.1141823] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/06/2023] [Indexed: 05/31/2023]
Abstract
Introduction Food security is a major challenge to sustainably supply food to meet the demands of the ever-growing global population. Crop loss due to pathogens is a major concern to overcoming this global food security challenge. Soybean root and stem rot caused by Phytophthora sojae results in approximately 20B $US crop loss annually. Phyto-oxylipins are metabolites biosynthesized in the plants by oxidative transformation of polyunsaturated fatty acids through an array of diverging metabolic pathways and play an important role in plant development and defense against pathogen colonization and infection. Lipid mediated plant immunity is a very attractive target for developing long term resistance in many plants' disease pathosystem. However, little is known about the phyto-oxylipin's role in the successful strategies used by tolerant soybean cultivar to mitigate Phytophthora sojae infection. Methods We used scanning electron microscopy to observe the alterations in root morphology and a targeted lipidomics approach using high resolution accurate mass tandem mass spectrometry to assess phyto-oxylipin anabolism at 48 h, 72 h and 96 h post infection. Results and discussion We observed the presence of biogenic crystals and reinforced epidermal walls in the tolerant cultivar suggesting a mechanism for disease tolerance when compared with susceptible cultivar. Similarly, the unequivocally unique biomarkers implicated in oxylipin mediated plant immunity [10(E),12(Z)-13S-hydroxy-9(Z),11(E),15(Z)-octadecatrienoic acid, (Z)-12,13-dihydroxyoctadec-9-enoic acid, (9Z,11E)-13-Oxo-9,11-octadecadienoic acid, 15(Z)-9-oxo-octadecatrienoic acid, 10(E),12(E)-9-hydroperoxyoctadeca-10,12-dienoic acid, 12-oxophytodienoic acid and (12Z,15Z)-9, 10-dihydroxyoctadeca-12,15-dienoic acid] generated from intact oxidized lipid precursors were upregulated in tolerant soybean cultivar while downregulated in infected susceptible cultivar relative to non-inoculated controls at 48 h, 72 h and 96 h post infection by Phytophthora sojae, suggesting that these molecules may be a critical component of the defense strategies used in tolerant cultivar against Phytophthora sojae infection. Interestingly, microbial originated oxylipins, 12S-hydroperoxy-5(Z),8(Z),10(E),14(Z)-eicosatetraenoic acid and (4Z,7Z,10Z,13Z)-15-[3-[(Z)-pent-2-enyl]oxiran-2-yl]pentadeca-4,7,10,13-tetraenoic acid were upregulated only in infected susceptible cultivar but downregulated in infected tolerant cultivar. These microbial originated oxylipins are capable of modulating plant immune response to enhance virulence. This study demonstrated novel evidence for phyto-oxylipin metabolism in soybean cultivars during pathogen colonization and infection using the Phytophthora sojae-soybean pathosystem. This evidence may have potential applications in further elucidation and resolution of the role of phyto-oxylipin anabolism in soybean tolerance to Phytophthora sojae colonization and infection.
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Affiliation(s)
- Oludoyin Adeseun Adigun
- School of Science and the Environment, Boreal Ecosystems and Agricultural Sciences, Grenfell Campus, Memorial University of Newfoundland, Corner Brook, NL, Canada
| | - Thu Huong Pham
- School of Science and the Environment, Boreal Ecosystems and Agricultural Sciences, Grenfell Campus, Memorial University of Newfoundland, Corner Brook, NL, Canada
| | - Dmitry Grapov
- Creative Data Solution (CDS), Colfax, CA, United States
| | - Muhammad Nadeem
- School of Science and the Environment, Boreal Ecosystems and Agricultural Sciences, Grenfell Campus, Memorial University of Newfoundland, Corner Brook, NL, Canada
| | - Linda Elizabeth Jewell
- St. John’s Research and Development Centre, Agriculture and Agri-Food Canada, St. John’s, NL, Canada
| | - Mumtaz Cheema
- School of Science and the Environment, Boreal Ecosystems and Agricultural Sciences, Grenfell Campus, Memorial University of Newfoundland, Corner Brook, NL, Canada
| | - Lakshman Galagedara
- School of Science and the Environment, Boreal Ecosystems and Agricultural Sciences, Grenfell Campus, Memorial University of Newfoundland, Corner Brook, NL, Canada
| | - Raymond Thomas
- School of Science and the Environment, Boreal Ecosystems and Agricultural Sciences, Grenfell Campus, Memorial University of Newfoundland, Corner Brook, NL, Canada
- Department of Biology/Biotron Climate Change Experimental Research Centre, Western University, London, ON, Canada
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Silhavy J, Mlejnek P, Šimáková M, Marková I, Malínská H, Hüttl M, Kazdová L, Kazantsev D, Mancini M, Novotný J, Pravenec M. CD36 regulates substrates utilisation in brown adipose tissue of spontaneously hypertensive rats: In vitro study. PLoS One 2023; 18:e0283276. [PMID: 37053180 PMCID: PMC10101526 DOI: 10.1371/journal.pone.0283276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 03/06/2023] [Indexed: 04/14/2023] Open
Abstract
Thermogenesis in brown adipose tissue (BAT) uses intracellular triglycerides, circulating free fatty acids and glucose as the main substrates. The objective of the current study was to analyse the role of CD36 fatty acid translocase in regulation of glucose and fatty acid utilisation in BAT. BAT isolated from spontaneously hypertensive rat (SHR) with mutant Cd36 gene and SHR-Cd36 transgenic rats with wild type variant was incubated in media containing labeled glucose and palmitate to measure substrate incorporation and oxidation. SHR-Cd36 versus SHR rats showed significantly increased glucose incorporation into intracellular lipids associated with reduced glycogen synthase kinase 3β (GSK-3β) protein expression and phosphorylation and increased oxidation of exogenous palmitate. It can be concluded that CD36 enhances glucose transport for lipogenesis in BAT by suppressing GSK-3β and promotes direct palmitate oxidation.
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Affiliation(s)
- Jan Silhavy
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Petr Mlejnek
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Miroslava Šimáková
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Irena Marková
- Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Hana Malínská
- Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Martina Hüttl
- Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Ludmila Kazdová
- Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Dmitry Kazantsev
- Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic
- 1st Faculty of Medicine, Institute of Pathological Physiology, Charles University, Prague, Czech Republic
| | - Massimiliano Mancini
- Division of Morphologic and Molecular Pathology, S. Andrea Hospital, Sapienza, University of Rome, Rome, Italy
| | - Jiří Novotný
- Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Michal Pravenec
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
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10
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Sharma AK, Wang T, Othman A, Khandelwal R, Balaz M, Modica S, Zamboni N, Wolfrum C. Basal re-esterification finetunes mitochondrial fatty acid utilization. Mol Metab 2023; 71:101701. [PMID: 36878315 PMCID: PMC10011057 DOI: 10.1016/j.molmet.2023.101701] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 02/27/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023] Open
Abstract
OBJECTIVE Emerging evidence suggest the existence of constant basal lipolysis and re-esterification of a substantial fraction of thus liberated fatty acids. In stimulated lipolysis, the re-esterification is proposed to be a protective mechanism against lipotoxicity; however, the role of the lipolysis coupled to re-esterification under basal conditions has not been deciphered. METHODS We used adipocytes (in vitro differentiated brown and white adipocytes derived from a cell line or primary SVF culture) to study the effect of inhibition of re-esterification by pharmacological DGAT1 and DGAT2 inhibitors alone or in combination. We then evaluated cellular energetics, lipolysis flux, and lipidomic parameters along with mitochondrial properties and fuel utilization. RESULTS In adipocytes, DGAT1 and 2 mediated re-esterification is a moderator of fatty acid oxidation. Combined inhibition of both DGATs (D1+2i) increases oxygen consumption, which is largely due to enhanced mitochondrial respiration by lipolysis-derived fatty acids (FAs). Acute D1+2i selectively affects mitochondrial respiration without affecting the transcriptional homeostasis of genes relevant to mitochondrial health and lipid metabolism. D1+2i enhances the mitochondrial import of pyruvate and activates AMP Kinase to counteract CPT1 antagonism, thus facilitating the mitochondrial import of fatty acyl-CoA. CONCLUSIONS These data implicate the process of re-esterification in the regulation of mitochondrial FA usage and uncover a mechanism of FAO regulation via crosstalk with FA re-esterification.
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Affiliation(s)
- Anand Kumar Sharma
- Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland
| | - Tongtong Wang
- Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland
| | - Alaa Othman
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
| | - Radhika Khandelwal
- Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland
| | - Miroslav Balaz
- Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland; Laboratory of Cellular and Molecular Metabolism, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Salvatore Modica
- Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland
| | - Nicola Zamboni
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
| | - Christian Wolfrum
- Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland.
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Abstract
Brown adipose tissue (BAT) displays the unique capacity to generate heat through uncoupled oxidative phosphorylation that makes it a very attractive therapeutic target for cardiometabolic diseases. Here, we review BAT cellular metabolism, its regulation by the central nervous and endocrine systems and circulating metabolites, the plausible roles of this tissue in human thermoregulation, energy balance, and cardiometabolic disorders, and the current knowledge on its pharmacological stimulation in humans. The current definition and measurement of BAT in human studies relies almost exclusively on BAT glucose uptake from positron emission tomography with 18F-fluorodeoxiglucose, which can be dissociated from BAT thermogenic activity, as for example in insulin-resistant states. The most important energy substrate for BAT thermogenesis is its intracellular fatty acid content mobilized from sympathetic stimulation of intracellular triglyceride lipolysis. This lipolytic BAT response is intertwined with that of white adipose (WAT) and other metabolic tissues, and cannot be independently stimulated with the drugs tested thus far. BAT is an interesting and biologically plausible target that has yet to be fully and selectively activated to increase the body's thermogenic response and shift energy balance. The field of human BAT research is in need of methods able to directly, specifically, and reliably measure BAT thermogenic capacity while also tracking the related thermogenic responses in WAT and other tissues. Until this is achieved, uncertainty will remain about the role played by this fascinating tissue in human cardiometabolic diseases.
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Affiliation(s)
- André C Carpentier
- Correspondence: André C. Carpentier, MD, Division of Endocrinology, Faculty of Medicine, University of Sherbrooke, 3001, 12th Ave N, Sherbrooke, Quebec, J1H 5N4, Canada.
| | - Denis P Blondin
- Division of Neurology, Department of Medicine, Centre de recherche du Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Quebec, J1H 5N4, Canada
| | | | - Denis Richard
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Quebec City, Quebec, G1V 4G5, Canada
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12
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Livelo C, Guo Y, Abou Daya F, Rajasekaran V, Varshney S, Le HD, Barnes S, Panda S, Melkani GC. Time-restricted feeding promotes muscle function through purine cycle and AMPK signaling in Drosophila obesity models. Nat Commun 2023; 14:949. [PMID: 36810287 PMCID: PMC9944249 DOI: 10.1038/s41467-023-36474-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 02/01/2023] [Indexed: 02/23/2023] Open
Abstract
Obesity caused by genetic and environmental factors can lead to compromised skeletal muscle function. Time-restricted feeding (TRF) has been shown to prevent muscle function decline from obesogenic challenges; however, its mechanism remains unclear. Here we demonstrate that TRF upregulates genes involved in glycine production (Sardh and CG5955) and utilization (Gnmt), while Dgat2, involved in triglyceride synthesis is downregulated in Drosophila models of diet- and genetic-induced obesity. Muscle-specific knockdown of Gnmt, Sardh, and CG5955 lead to muscle dysfunction, ectopic lipid accumulation, and loss of TRF-mediated benefits, while knockdown of Dgat2 retains muscle function during aging and reduces ectopic lipid accumulation. Further analyses demonstrate that TRF upregulates the purine cycle in a diet-induced obesity model and AMPK signaling-associated pathways in a genetic-induced obesity model. Overall, our data suggest that TRF improves muscle function through modulations of common and distinct pathways under different obesogenic challenges and provides potential targets for obesity treatments.
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Affiliation(s)
- Christopher Livelo
- Department of Pathology, Division of Molecular and Cellular Pathology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Yiming Guo
- Department of Pathology, Division of Molecular and Cellular Pathology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Farah Abou Daya
- Department of Pathology, Division of Molecular and Cellular Pathology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Vasanthi Rajasekaran
- Department of Pathology, Division of Molecular and Cellular Pathology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Shweta Varshney
- Regulatory Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
- Department of Biology, Molecular Biology Institute, San Diego State University, San Diego, CA, 92182, USA
| | - Hiep D Le
- Regulatory Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Stephen Barnes
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Satchidananda Panda
- Regulatory Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Girish C Melkani
- Department of Pathology, Division of Molecular and Cellular Pathology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
- Department of Biology, Molecular Biology Institute, San Diego State University, San Diego, CA, 92182, USA.
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13
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Abstract
Lipids are a class of complex hydrophobic molecules derived from fatty acids that not only form the structural basis of biological membranes but also regulate metabolism and maintain energy balance. The role of lipids in obesity and other metabolic diseases has recently received much attention, making lipid metabolism one of the attractive research areas. Several metabolic diseases are linked to lipid metabolism, including diabetes, obesity, and atherosclerosis. Additionally, lipid metabolism contributes to the rapid growth of cancer cells as abnormal lipid synthesis or uptake enhances the growth of cancer cells. This review introduces the potential drug targets in lipid metabolism and summarizes the important potential drug targets with recent research progress on the corresponding small molecule inhibitor drugs. The significance of this review is to provide a reference for the clinical treatment of metabolic diseases related to lipid metabolism and the treatment of tumors, hoping to deepen the understanding of lipid metabolism and health.
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Affiliation(s)
- Kai Liang
- School of Life Science, Peking University, Beijing, China,*Correspondence: Kai Liang, ; Jian-Ye Dai,
| | - Jian-Ye Dai
- School of Pharmacy, Lanzhou University, Lanzhou, China,Collaborative Innovation Center for Northwestern Chinese Medicine, Lanzhou University, Lanzhou, China,*Correspondence: Kai Liang, ; Jian-Ye Dai,
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14
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Shi H, Zhao J, Li Y, Li J, Li Y, Zhang J, Qiu Z, Wu C, Qin M, Liu C, Zeng Z, Zhang C, Gao L. Ginsenosides Rg1 regulate lipid metabolism and temperature adaptation in Caenorhabditis elegans. J Ginseng Res 2022. [DOI: 10.1016/j.jgr.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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15
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Winichayakul S, Curran A, Moraga R, Cookson R, Xue H, Crowther T, Roldan M, Bryan G, Roberts N. An alternative angiosperm DGAT1 topology and potential motifs in the N-terminus. Front Plant Sci 2022; 13:951389. [PMID: 36186081 PMCID: PMC9523541 DOI: 10.3389/fpls.2022.951389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 08/05/2022] [Indexed: 06/16/2023]
Abstract
The highly variable cytoplasmic N-terminus of the plant diacylglycerol acyltransferase 1 (DGAT1) has been shown to have roles in oligomerization as well as allostery; however, the biological significance of the variation within this region is not understood. Comparing the coding sequences over the variable N-termini revealed the Poaceae DGAT1s contain relatively high GC compositional gradients as well as numerous direct and inverted repeats in this region. Using a variety of reciprocal chimeric DGAT1s from angiosperms we show that related N-termini had similar effects (positive or negative) on the accumulation of the recombinant protein in Saccharomyces cerevisiae. When expressed in Camelina sativa seeds the recombinant proteins of specific chimeras elevated total lipid content of the seeds as well as increased seed size. In addition, we combine N- and C-terminal as well as internal tags with high pH membrane reformation, protease protection and differential permeabilization. This led us to conclude the C-terminus is in the ER lumen; this contradicts earlier reports of the cytoplasmic location of plant DGAT1 C-termini.
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Affiliation(s)
- Somrutai Winichayakul
- Resilient Agriculture Innovation Centre of Excellence, AgResearch Ltd., Palmerston North, New Zealand
| | - Amy Curran
- ZeaKal Inc., San Diego, CA, United States
| | - Roger Moraga
- Bioinformatics and Statistics, AgResearch Ltd., Palmerston North, New Zealand
| | - Ruth Cookson
- Resilient Agriculture Innovation Centre of Excellence, AgResearch Ltd., Palmerston North, New Zealand
| | - Hong Xue
- Resilient Agriculture Innovation Centre of Excellence, AgResearch Ltd., Palmerston North, New Zealand
| | - Tracey Crowther
- Resilient Agriculture Innovation Centre of Excellence, AgResearch Ltd., Palmerston North, New Zealand
| | - Marissa Roldan
- Resilient Agriculture Innovation Centre of Excellence, AgResearch Ltd., Palmerston North, New Zealand
| | - Greg Bryan
- Resilient Agriculture Innovation Centre of Excellence, AgResearch Ltd., Palmerston North, New Zealand
- ZeaKal Inc., San Diego, CA, United States
| | - Nick Roberts
- Resilient Agriculture Innovation Centre of Excellence, AgResearch Ltd., Palmerston North, New Zealand
- ZeaKal Inc., San Diego, CA, United States
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16
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Ying Z, Tramper N, Zhou E, Boon MR, Rensen PCN, Kooijman S. Role of thermogenic adipose tissue in lipid metabolism and atherosclerotic cardiovascular disease: lessons from studies in mice and humans. Cardiovasc Res 2022; 119:905-918. [PMID: 35944189 PMCID: PMC10153643 DOI: 10.1093/cvr/cvac131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 05/09/2022] [Accepted: 06/02/2022] [Indexed: 11/12/2022] Open
Abstract
Brown adipocytes within brown adipose tissue (BAT) and beige adipocytes within white adipose tissue dissipate nutritional energy as heat. Studies in mice have shown that activation of thermogenesis in brown and beige adipocytes enhances the lipolytic processing of triglyceride-rich lipoproteins (TRLs) in plasma to supply these adipocytes with fatty acids for oxidation. This process results in formation of TRL remnants that are removed from the circulation through binding of apolipoprotein E (ApoE) on their surface to the low-density lipoprotein receptor (LDLR) on hepatocytes, followed by internalization. Concomitantly, lipolytic processing of circulating TRLs leads to generation of excess surface phospholipids that are transferred to nascent high-density lipoproteins (HDL), increasing their capacity for reverse cholesterol transport. Activation of thermogenic adipocytes thus lowers circulating triglycerides and non-HDL-cholesterol, while it increases HDL-cholesterol. The combined effect is protection from atherosclerosis development, which becomes evident in humanized mouse models with an intact ApoE-LDLR clearance pathway only, and is additive to the effects of classical lipid-lowering drugs including statins and proprotein convertase subtilisin/kexin type 9 inhibitors. A large recent study revealed that the presence of metabolically active BAT in humans is associated with lower triglycerides, higher HDL-cholesterol and lower risk of cardiovascular diseases. This narrative review aims to provide leads for further exploration of thermogenic adipose tissue as a therapeutic target. To this end, we describe the latest knowledge on the role of BAT in lipoprotein metabolism and address, for example, the discovery of the β2-adrenergic receptor as the dominant adrenergic receptor in human thermogenic adipocytes.
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Affiliation(s)
- Zhixiong Ying
- Department of Medicine, Division of Endocrinology, Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Naomi Tramper
- Department of Medicine, Division of Endocrinology, Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Enchen Zhou
- Department of Medicine, Division of Endocrinology, Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Mariëtte R Boon
- Department of Medicine, Division of Endocrinology, Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
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17
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Chen G, Harwood JL, Lemieux MJ, Stone SJ, Weselake RJ. Acyl-CoA:diacylglycerol acyltransferase: Properties, physiological roles, metabolic engineering and intentional control. Prog Lipid Res 2022; 88:101181. [PMID: 35820474 DOI: 10.1016/j.plipres.2022.101181] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/31/2022] [Accepted: 07/04/2022] [Indexed: 12/15/2022]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) catalyzes the last reaction in the acyl-CoA-dependent biosynthesis of triacylglycerol (TAG). DGAT activity resides mainly in membrane-bound DGAT1 and DGAT2 in eukaryotes and bifunctional wax ester synthase-diacylglycerol acyltransferase (WSD) in bacteria, which are all membrane-bound proteins but exhibit no sequence homology to each other. Recent studies also identified other DGAT enzymes such as the soluble DGAT3 and diacylglycerol acetyltransferase (EaDAcT), as well as enzymes with DGAT activities including defective in cuticular ridges (DCR) and steryl and phytyl ester synthases (PESs). This review comprehensively discusses research advances on DGATs in prokaryotes and eukaryotes with a focus on their biochemical properties, physiological roles, and biotechnological and therapeutic applications. The review begins with a discussion of DGAT assay methods, followed by a systematic discussion of TAG biosynthesis and the properties and physiological role of DGATs. Thereafter, the review discusses the three-dimensional structure and insights into mechanism of action of human DGAT1, and the modeled DGAT1 from Brassica napus. The review then examines metabolic engineering strategies involving manipulation of DGAT, followed by a discussion of its therapeutic applications. DGAT in relation to improvement of livestock traits is also discussed along with DGATs in various other eukaryotic organisms.
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Affiliation(s)
- Guanqun Chen
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Membrane Protein Disease Research Group, Edmonton T6G 2H7, Canada
| | - Scot J Stone
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Randall J Weselake
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada
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18
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Abstract
Non-alcoholic fatty liver disease (NAFLD) is a growing cause of chronic liver disease worldwide. It is characterised by steatosis, liver inflammation, hepatocellular injury and progressive fibrosis. Several preclinical models (dietary and genetic animal models) of NAFLD have deepened our understanding of its aetiology and pathophysiology. Despite the progress made, there are currently no effective treatments for NAFLD. In this review, we will provide an update on the known molecular pathways involved in the pathophysiology of NAFLD and on ongoing studies of new therapeutic targets.
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Key Words
- ACC, acetyl-CoA carboxylase
- ASK1, apoptosis signal-regulating kinase 1
- CAP, controlled attenuation parameter
- ChREBP
- ChREBP, carbohydrate responsive element–binding protein
- FAS, fatty acid synthase
- FFA, free fatty acid
- FGF21, fibroblast growth factor-21
- FXR
- FXR, farnesoid X receptor
- GGT, gamma glutamyltransferase
- HCC, hepatocellular carcinoma
- HFD, high-fat diet
- HSC, hepatic stellate cells
- HSL, hormone-sensitive lipase
- HVPG, hepatic venous pressure gradient
- IL-, interleukin-
- JNK, c-Jun N-terminal kinase
- LXR
- LXR, liver X receptor
- MCD, methionine- and choline-deficient
- MUFA, monounsaturated fatty acids
- NAFLD
- NAFLD, non-alcoholic fatty liver disease
- NASH
- NASH, non-alcoholic steatohepatitis
- NEFA
- NEFA, non-esterified fatty acid
- PPARα
- PPARα, peroxisome proliferator-activated receptor-α
- PUFAs, polyunsaturated fatty acids
- PY, persons/years
- Phf2, histone demethylase plant homeodomain finger 2
- RCT, randomised controlled trial
- SCD1, stearoyl-CoA desaturase-1
- SFA, saturated fatty acid
- SREBP-1c
- SREBP-1c, sterol regulatory element–binding protein-1c
- TCA, tricarboxylic acid
- TLR4, Toll-like receptor 4
- TNF-α, tumour necrosis factor-α
- VLDL, very low-density lipoprotein
- animal models
- glucotoxicity
- lipotoxicity
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Affiliation(s)
- Lucia Parlati
- Université de Paris, Institut Cochin, CNRS, INSERM, F- 75014 Paris, France.,Hôpital Cochin, 24, rue du Faubourg Saint Jacques, 75014 Paris, France
| | - Marion Régnier
- UCLouvain, Université catholique de Louvain, Walloon Excellence in Life Sciences and BIOtechnology, Louvain Drug Research Institute, Metabolism and Nutrition Research Group, Brussels, Belgium
| | - Hervé Guillou
- Toxalim, Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse 31027, France
| | - Catherine Postic
- Université de Paris, Institut Cochin, CNRS, INSERM, F- 75014 Paris, France
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19
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Yoon H, Shaw JL, Haigis MC, Greka A. Lipid metabolism in sickness and in health: Emerging regulators of lipotoxicity. Mol Cell 2021; 81:3708-3730. [PMID: 34547235 PMCID: PMC8620413 DOI: 10.1016/j.molcel.2021.08.027] [Citation(s) in RCA: 104] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/10/2021] [Accepted: 08/19/2021] [Indexed: 12/12/2022]
Abstract
Lipids play crucial roles in signal transduction, contribute to the structural integrity of cellular membranes, and regulate energy metabolism. Questions remain as to which lipid species maintain metabolic homeostasis and which disrupt essential cellular functions, leading to metabolic disorders. Here, we discuss recent advances in understanding lipid metabolism with a focus on catabolism, synthesis, and signaling. Technical advances, including functional genomics, metabolomics, lipidomics, lipid-protein interaction maps, and advances in mass spectrometry, have uncovered new ways to prioritize molecular mechanisms mediating lipid function. By reviewing what is known about the distinct effects of specific lipid species in physiological pathways, we provide a framework for understanding newly identified targets regulating lipid homeostasis with implications for ameliorating metabolic diseases.
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Affiliation(s)
- Haejin Yoon
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA; Ludwig Center for Cancer Research at Harvard, Boston, MA 02115, USA
| | - Jillian L Shaw
- Kidney Disease Initiative, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Marcia C Haigis
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA; Ludwig Center for Cancer Research at Harvard, Boston, MA 02115, USA.
| | - Anna Greka
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Kidney Disease Initiative, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
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20
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Gallardo-Montejano VI, Yang C, Hahner L, McAfee JL, Johnson JA, Holland WL, Fernandez-Valdivia R, Bickel PE. Perilipin 5 links mitochondrial uncoupled respiration in brown fat to healthy white fat remodeling and systemic glucose tolerance. Nat Commun 2021; 12:3320. [PMID: 34083525 PMCID: PMC8175597 DOI: 10.1038/s41467-021-23601-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 04/28/2021] [Indexed: 02/06/2023] Open
Abstract
Exposure of mice or humans to cold promotes significant changes in brown adipose tissue (BAT) with respect to histology, lipid content, gene expression, and mitochondrial mass and function. Herein we report that the lipid droplet coat protein Perilipin 5 (PLIN5) increases markedly in BAT during exposure of mice to cold. To understand the functional significance of cold-induced PLIN5, we created and characterized gain- and loss-of-function mouse models. Enforcing PLIN5 expression in mouse BAT mimics the effects of cold with respect to mitochondrial cristae packing and uncoupled substrate-driven respiration. PLIN5 is necessary for the maintenance of mitochondrial cristae structure and respiratory function during cold stress. We further show that promoting PLIN5 function in BAT is associated with healthy remodeling of subcutaneous white adipose tissue and improvements in systemic glucose tolerance and diet-induced hepatic steatosis. These observations will inform future strategies that seek to exploit thermogenic adipose tissue as a therapeutic target for type 2 diabetes, obesity, and nonalcoholic fatty liver disease. Perilipin 5 is a lipid droplet protein that interacts with PGC1α in the nucleus to regulate mitochondrial metabolism. Here the authors use genetically engineered mouse models to determine the physiologic role of Perilipin 5, and show that it regulates mitochondrial adaptations to cold, as well as systemic energy metabolism.
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Affiliation(s)
- Violeta I Gallardo-Montejano
- Division of Endocrinology, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Chaofeng Yang
- Division of Endocrinology, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Lisa Hahner
- Division of Endocrinology, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - John L McAfee
- Division of Endocrinology, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA.,Pathology and Laboratory Medicine Institute, Cleveland, OH, USA
| | - Joshua A Johnson
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - William L Holland
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA.,Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, UT, USA
| | | | - Perry E Bickel
- Division of Endocrinology, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
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21
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Wang Z, Wang QA, Liu Y, Jiang L. Energy metabolism in brown adipose tissue. FEBS J 2021; 288:3647-3662. [PMID: 34028971 DOI: 10.1111/febs.16015] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/06/2021] [Accepted: 05/12/2021] [Indexed: 12/14/2022]
Abstract
Brown adipose tissue (BAT) is well known to burn calories through uncoupled respiration, producing heat to maintain body temperature. This 'calorie wasting' feature makes BAT a special tissue, which can function as an 'energy sink' in mammals. While a combination of high energy intake and low energy expenditure is the leading cause of overweight and obesity in modern society, activating a safe 'energy sink' has been proposed as a promising obesity treatment strategy. Metabolically, lipids and glucose have been viewed as the major energy substrates in BAT, while succinate, lactate, branched-chain amino acids, and other metabolites can also serve as energy substrates for thermogenesis. Since the cataplerotic and anaplerotic reactions of these metabolites interconnect with each other, BAT relies on its dynamic, flexible, and complex metabolism to support its special function. In this review, we summarize how BAT orchestrates the metabolic utilization of various nutrients to support thermogenesis and contributes to whole-body metabolic homeostasis.
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Affiliation(s)
- Zhichao Wang
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Duarte, CA, USA
| | - Qiong A Wang
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Duarte, CA, USA.,Comprehensive Cancer Center, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, USA
| | - Yong Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Institute for Advanced Studies, Wuhan University, China
| | - Lei Jiang
- Department of Molecular & Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Duarte, CA, USA.,Comprehensive Cancer Center, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, USA
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22
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Michurina SS, Stafeev IS, Menshikov MY, Parfyonova YV. Mitochondrial dynamics keep balance of nutrient combustion in thermogenic adipocytes. Mitochondrion 2021; 59:157-168. [PMID: 34010673 DOI: 10.1016/j.mito.2021.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/02/2021] [Accepted: 05/13/2021] [Indexed: 12/21/2022]
Abstract
Non-shivering thermogenesis takes place in brown and beige adipocytes and facilitates cold tolerance and acclimation. However, thermogenesis in adipose tissue also was found to be activated in metabolic overload states for fast utilization of nutrients excess. This observation spurred research interest in mechanisms of thermogenesis regulation for metabolic overload and obesity prevention. One of proposed regulators of thermogenic efficiency in adipocytes is the dynamics of mitochondria, where thermogenesis takes place. Indeed, brown and beige adipocytes exhibit fragmented round-shaped mitochondria, while white adipocytes have elongated organelles with high ATP synthesis. Mitochondrial morphology can determine uncoupling protein 1 (UCP1) content, efficiency of catabolic pathways and electron transport chain, supplying thermogenesis. This review will highlight the co-regulation of mitochondrial dynamics and thermogenesis and formulate hypothetical ways for excessive nutrients burning in response to mitochondrial morphology manipulation.
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Affiliation(s)
- S S Michurina
- Lomonosov Moscow State University, 119234 Moscow, Russia; Institute of Experimental Cardiology, National Medical Research Centre for Cardiology, 121500 Moscow, Russia.
| | - I S Stafeev
- Institute of Experimental Cardiology, National Medical Research Centre for Cardiology, 121500 Moscow, Russia.
| | - M Y Menshikov
- Institute of Experimental Cardiology, National Medical Research Centre for Cardiology, 121500 Moscow, Russia
| | - Ye V Parfyonova
- Lomonosov Moscow State University, 119234 Moscow, Russia; Institute of Experimental Cardiology, National Medical Research Centre for Cardiology, 121500 Moscow, Russia
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23
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Wunderling K, Leopold C, Jamitzky I, Yaghmour M, Zink F, Kratky D, Thiele C. Hepatic synthesis of triacylglycerols containing medium-chain fatty acids is dominated by diacylglycerol acyltransferase 1 and efficiently inhibited by etomoxir. Mol Metab 2021; 45:101150. [PMID: 33359403 DOI: 10.1016/j.molmet.2020.101150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/07/2020] [Accepted: 12/16/2020] [Indexed: 11/30/2022] Open
Abstract
Objective Medium-chain fatty acids (MCFAs) play an increasing role in human nutrition. In the liver, one fraction is used for synthesis of MCFA-containing triacylglycerol (MCFA-TG), and the rest is used for oxidative energy production or ketogenesis. We investigated which enzymes catalyse the synthesis of MCFA-TG and how inhibition of MCFA-TG synthesis or fatty acid (FA) oxidation influences the metabolic fate of the MCFAs. Methods FA metabolism was followed by time-resolved tracing of alkyne-labelled FAs in freshly isolated mouse hepatocytes. Quantitative data were obtained by mass spectrometry of several hundred labelled lipid species. Wild-type hepatocytes and cells from diacylglycerol acyltransferase (DGAT)1−/− mice were treated with inhibitors against DGAT1, DGAT2, or FA β-oxidation. Results Inhibition or deletion of DGAT1 resulted in a reduction of MCFA-TG synthesis by 70%, while long-chain (LC)FA-TG synthesis was reduced by 20%. In contrast, DGAT2 inhibition increased MCFA-TG formation by 50%, while LCFA-TG synthesis was reduced by 5–25%. Inhibition of β-oxidation by the specific inhibitor teglicar strongly increased MCFA-TG synthesis. In contrast, the widely used β-oxidation inhibitor etomoxir blocked MCFA-TG synthesis, phenocopying DGAT1 inhibition. Conclusions DGAT1 is the major enzyme for hepatic MCFA-TG synthesis. Its loss can only partially be compensated by DGAT2. Specific inhibition of β-oxidation leads to a compensatory increase in MCFA-TG synthesis, whereas etomoxir blocks both β-oxidation and MCFA-TG synthesis, indicating a strong off-target effect on DGAT1.
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24
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Wang G, Yu Y, Wang YZ, Zhu ZM, Yin PH, Xu K. Effects and mechanisms of fatty acid metabolism‑mediated glycolysis regulated by betulinic acid‑loaded nanoliposomes in colorectal cancer. Oncol Rep 2020; 44:2595-2609. [PMID: 33125108 PMCID: PMC7640364 DOI: 10.3892/or.2020.7787] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 06/03/2020] [Indexed: 01/05/2023] Open
Abstract
Although previous studies have demonstrated that triterpenoids, such as betulinic acid (BA), can inhibit tumor cell growth, their potential targets in colorectal cancer (CRC) metabolism have not been systematically investigated. In the present study, BA‑loaded nanoliposomes (BA‑NLs) were prepared, and their effects on CRC cell lines were evaluated. The aim of the present study was to determine the anticancer mechanisms of action of BA‑NLs in fatty acid metabolism‑mediated glycolysis, and investigate the role of key targets, such as acyl‑CoA synthetase (ACSL), carnitine palmitoyltransferase (CPT) and acetyl CoA, in promoting glycolysis, which is activated by inducing hexokinase (HK), phosphofructokinase‑1 (PFK‑1), phosphoenolpyruvate (PEP) and pyruvate kinase (PK) expression. The results demonstrated that BA‑NLs significantly suppressed the proliferation and glucose uptake of CRC cells by regulating potential glycolysis and fatty acid metabolism targets and pathways, which forms the basis of the anti‑CRC function of BA‑NLs. Moreover, the effects of BA‑NLs were further validated by demonstrating that the key targets of HK2, PFK‑1, PEP and PK isoenzyme M2 (PKM2) in glycolysis, and of ACSL1, CPT1a and PEP in fatty acid metabolism, were blocked by BA‑NLs, which play key roles in the inhibition of glycolysis and fatty acid‑mediated production of pyruvate and lactate. The results of the present study may provide a deeper understanding supporting the hypothesis that liposomal BA may regulate alternative metabolic pathways implicated in CRC adjuvant therapy.
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Affiliation(s)
- Gang Wang
- Department of Pharmaceutics, Shanghai Eighth People's Hospital, Jiangsu University, Shanghai 200235, P.R. China
| | - Yang Yu
- Jiangsu University School of Pharmacy, Zhenjiang, Jiangsu 212001, P.R. China
| | - Yu-Zhu Wang
- Jiangsu University School of Pharmacy, Zhenjiang, Jiangsu 212001, P.R. China
| | - Zhi-Min Zhu
- Department of Pharmaceutics, Shanghai Eighth People's Hospital, Jiangsu University, Shanghai 200235, P.R. China
| | - Pei-Hao Yin
- Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, P.R. China
| | - Ke Xu
- Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, P.R. China
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Abstract
This study aimed to explore the effects of 1,25(OH)2 D3 on lipid droplet (LD) growth in 3T3-L1 adipocytes of hypertrophy model. Cocktail method was used to induce differentiation in 3T3-L1 cells. After 8 days, the cells were modeled by 100, 300, 600, and 900 μM palmitic acid (PA) for 24 hr. The best concentration of modeling was screened by MTT results and triglycerides (TG) content. The model cells were intervened by 1, 10, and 100 nM 1,25(OH)2 D3 for 24 hr. Then, the TG content of cells were detected and stained by oil red O. The diameter and quantity of LDs were analyzed. mRNA relative expression levels of genes related to LD (CIDE-a, Fsp27, PLIN-1), upstream response factor (PPAR-α, PPAR-γ, and VDR), and TG metabolism (long chain acyl-CoA synthetase 3, 1-acylglycerol-3-phosphate O-acyltransferase 1, adipose triglyceride lipase, diacylglycerol acyltransferase 1, diacylglycerol acyltransferase 2, glycerol-3-phosphate O-acyltransferase 3, glycerol-3-phosphate O-acyltransferase 4, hormone-sensitive lipase, mannosyl (alpha-1,3-)-glycoprotein beta-1,2-N-acetyl glucosaminyl transferase, phosphatidic acid phosphatase, and uncoupling protein-1) were detected by RT-qPCR. A total of 300 μM PA was selected as the optimum concentration. Compared with model group, 10 and 100 nM 1,25(OH)2 D3 decreased the average diameter, increased the quantity of LDs, upregulated PPAR-α and PLIN-1 mRNA expression levels, and downregulated CIDE-a and Fsp27 mRNA expression levels significantly (p < .05). However, 1 nM 1,25(OH)2 D3 did not alter LD morphology and TG content. mRNA expression levels of long chain acyl-CoA synthetase 3, 1-acylglycerol-3-phosphate O-acyltransferase 1, diacylglycerol acyltransferase 2, glycerol-3-phosphate O-acyltransferase 3, and glycerol-3-phosphate O-acyltransferase 4 in 10 and 100 nM groups were significantly lower than those in the model group (p < .05); mRNA expression levels of adipose triglyceride lipase, diacylglycerol acyltransferase 1, hormone-sensitive lipase, mannosyl (alpha-1,3-)-glycoprotein beta-1,2-N-acetyl glucosaminyl transferase, phosphatidic acid phosphatase, and uncoupling protein-1 were significantly increased in the 100 nM group (p < .05). The 10 and 100 nM 1,25(OH)2 D3 can inhibit LD fusion, promote LD decomposition, reduce LD volume, and inhibit lipogenesis through the PPAR-α signaling pathway.
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Affiliation(s)
- Wei Xiang
- Department of Nutrition and Diet, Changzhou Traditional Chinese Medicine Hospital, Changzhou, China
| | - Shi Cheng
- Department of Nutrition and Food Hygiene, School of Public Health, Xinjiang Medical University, Urumqi, China
| | - Yong Zhou
- Department of Medical Cell Biology and Genetics, College of Preclinical Medicine, Southwest Medical University, Luzhou, China
| | - Ling Ma
- Department of Nutrition and Food Hygiene, School of Public Health, Southwest Medical University, Luzhou, China
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Wang Z, Ning T, Song A, Rutter J, Wang QA, Jiang L. Chronic cold exposure enhances glucose oxidation in brown adipose tissue. EMBO Rep 2020; 21:e50085. [PMID: 33043581 PMCID: PMC7645266 DOI: 10.15252/embr.202050085] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 09/02/2020] [Accepted: 09/10/2020] [Indexed: 01/20/2023] Open
Abstract
The cultured brown adipocytes can oxidize glucose in vitro, but it is still not fully clear whether brown adipose tissue (BAT) could completely oxidize glucose in vivo. Although positron emission tomography (PET) with 18F‐fluorodeoxyglucose (18F‐FDG) showed a high level of glucose uptake in the activated BAT, the non‐metabolizable 18F‐FDG cannot fully demonstrate intracellular glucose metabolism. Through in vivo [U‐13C]glucose tracing, here we show that chronic cold exposure dramatically activates glucose oxidation in BAT and the browning/beiging subcutaneous white adipose tissue (sWAT). Specifically, chronic cold exposure enhances glucose flux into the mitochondrial TCA cycle. Metabolic flux analysis models that β3‐adrenergic receptor (β3‐AR) agonist significantly enhances the flux of mitochondrial pyruvate uptake through mitochondrial pyruvate carrier (MPC) in the differentiated primary brown adipocytes. Furthermore, in vivo MPC inhibition blocks cold‐induced glucose oxidation and impairs body temperature maintenance in mice. Together, mitochondrial pyruvate uptake and oxidation serve an important energy source in the chronic cold exposure activated BAT and beige adipose tissue, which supports a role for glucose oxidation in brown fat thermogenesis.
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Affiliation(s)
- Zhichao Wang
- Department of Molecular & Cellular Endocrinology, Diabetes and Metabolism Research Institute, City of Hope Medical Center, Duarte, CA, USA
| | - Tinglu Ning
- Department of Molecular & Cellular Endocrinology, Diabetes and Metabolism Research Institute, City of Hope Medical Center, Duarte, CA, USA
| | - Anying Song
- Department of Molecular & Cellular Endocrinology, Diabetes and Metabolism Research Institute, City of Hope Medical Center, Duarte, CA, USA
| | - Jared Rutter
- Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT, USA.,Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Qiong A Wang
- Department of Molecular & Cellular Endocrinology, Diabetes and Metabolism Research Institute, City of Hope Medical Center, Duarte, CA, USA.,Comprehensive Cancer Center, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, USA
| | - Lei Jiang
- Department of Molecular & Cellular Endocrinology, Diabetes and Metabolism Research Institute, City of Hope Medical Center, Duarte, CA, USA.,Comprehensive Cancer Center, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, USA
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27
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Cañón-Beltrán K, Giraldo-Giraldo J, Cajas YN, Beltrán-Breña P, Hidalgo CO, Vásquez N, Leal CLV, Gutiérrez-Adán A, González EM, Rizos D. Inhibiting diacylglycerol acyltransferase-1 reduces lipid biosynthesis in bovine blastocysts produced in vitro. Theriogenology 2020; 158:267-276. [PMID: 33002770 DOI: 10.1016/j.theriogenology.2020.09.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/07/2020] [Accepted: 09/10/2020] [Indexed: 11/28/2022]
Abstract
Diacylglycerol acyltransferase-1 (DGAT1) is one of the DGAT enzymes that catalyzes the final step in the synthesis of triacylglycerol, which is a major component of the lipid droplets in embryos. Intracellular lipids accumulated in embryos produced in vitro have been associated with reduced cryotolerance and quality. The objective of the present study was to investigate the influence of DGAT1 inhibition on embryo development, quality, and post-vitrification survival, in addition to expression profiles of selected lipid metabolism-regulating and oxidative stress genes. Bovine cumulus-oocyte complexes were matured and fertilized in vitro and were cultured in synthetic oviduct fluid (SOF) supplemented with 5% fetal calf serum (FCS) alone (Control) or with 1, 5, 10 or 50 μM DGAT1 inhibitor (A922500®; D1, D5, D10, and D50, respectively) or 0.1% dimethyl sulfoxide (CDMSO: vehicle for DGAT1 inhibitor dilution) from 54 h post-insemination until Day 8 post insemination. No differences were found in blastocyst yield on days 7 and 8 in Control, CDMSO, D10, and D50 groups. Embryos cultured with 10 or 50 μM DGAT1 inhibitor had greater mitochondrial activity (P < 0.01), and increased number of cells (P < 0.05), while the cytoplasmic lipid content was reduced (P < 0.01), the latter associated with altered expression profiles of selected genes regulating lipid metabolism or genes related with oxidative stress (transcript abundance increased for SLC2A1 and SLC2A5 and decreased for DGAT1 and GPX1). Importantly, the survival rate of blastocysts produced with 10 μM DGAT1 was higher than that of Control, CDMSO and D50 groups at 72 h after vitrification and warming (73.8 vs 57.1, 55.9 and 56.1%, respectively, P < 0.001). In conclusion, inhibition of DGAT1 synthesis in bovine embryos produced in vitro abrogates the negative effect of FCS by decreasing their lipid content, increasing mitochondria activity and improving embryo cryotolerance, as well as favoring the expression of lipid metabolism regulating and oxidative stress-related transcripts.
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Affiliation(s)
- K Cañón-Beltrán
- Department of Animal Reproduction, National Institute for Agriculture and Food Research and Technology (INIA), Madrid, Spain; Departamento de Ciencias Biológicas, Universidad Técnica Particular de Loja, Loja, Ecuador
| | - J Giraldo-Giraldo
- Department of Animal Reproduction, National Institute for Agriculture and Food Research and Technology (INIA), Madrid, Spain; Reproductive Biotechnology Laboratory, School of Biosciences, Science Faculty, National University of Colombia, Medellín, Colombia
| | - Y N Cajas
- Department of Animal Reproduction, National Institute for Agriculture and Food Research and Technology (INIA), Madrid, Spain
| | - P Beltrán-Breña
- Department of Animal Reproduction, National Institute for Agriculture and Food Research and Technology (INIA), Madrid, Spain
| | - C O Hidalgo
- Department of Animal Selection and Reproduction, The Regional Agri-Food Research and Development Service of Asturias (SERIDA), Gijon, Spain
| | - N Vásquez
- Reproductive Biotechnology Laboratory, School of Biosciences, Science Faculty, National University of Colombia, Medellín, Colombia
| | - C L V Leal
- Department of Animal Reproduction, National Institute for Agriculture and Food Research and Technology (INIA), Madrid, Spain; Department of Veterinary Medicine, Faculty of Animal Science and Food Engineering, University of São Paulo, Pirassununga, Brazil
| | - A Gutiérrez-Adán
- Department of Animal Reproduction, National Institute for Agriculture and Food Research and Technology (INIA), Madrid, Spain
| | - E M González
- Department of Anatomy and Embryology, Veterinary Faculty, Complutense University of Madrid (UCM), Madrid, Spain
| | - D Rizos
- Department of Animal Reproduction, National Institute for Agriculture and Food Research and Technology (INIA), Madrid, Spain.
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28
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Fischer AW, Behrens J, Sass F, Schlein C, Heine M, Pertzborn P, Scheja L, Heeren J. Brown adipose tissue lipoprotein and glucose disposal is not determined by thermogenesis in uncoupling protein 1-deficient mice. J Lipid Res 2020; 61:1377-1389. [PMID: 32769145 DOI: 10.1194/jlr.ra119000455] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Adaptive thermogenesis is highly dependent on uncoupling protein 1 (UCP1), a protein expressed by thermogenic adipocytes present in brown adipose tissue (BAT) and white adipose tissue (WAT). Thermogenic capacity of human and mouse BAT can be measured by positron emission tomography-computed tomography quantifying the uptake of 18F-fluodeoxyglucose or lipid tracers. BAT activation is typically studied in response to cold exposure or treatment with β-3-adrenergic receptor agonists such as CL316,243 (CL). Currently, it is unknown whether cold-stimulated uptake of glucose or lipid tracers is a good surrogate marker of UCP1-mediated thermogenesis. In metabolic studies using radiolabeled tracers, we found that glucose uptake is increased in mildly cold-activated BAT of Ucp1 -/- versus WT mice kept at subthermoneutral temperature. Conversely, lower glucose disposal was detected after full thermogenic activation achieved by sustained cold exposure or CL treatment. In contrast, uptake of lipoprotein-derived fatty acids into chronically activated thermogenic adipose tissues was substantially increased in UCP1-deficient mice. This effect is linked to higher sympathetic tone in adipose tissues of Ucp1 -/- mice, as indicated by elevated levels of thermogenic genes in BAT and WAT. Thus, glucose and lipoprotein handling does not necessarily reflect UCP1-dependent thermogenic activity, but especially lipid uptake rather mirrors sympathetic activation of adipose tissues.
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Affiliation(s)
- Alexander W Fischer
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Janina Behrens
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Frederike Sass
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Schlein
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Markus Heine
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Paul Pertzborn
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ludger Scheja
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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29
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Paloschi MV, Lopes JA, Boeno CN, Silva MDS, Evangelista JR, Pontes AS, da Silva Setúbal S, Rego CMA, Néry NM, Ferreira E Ferreira AA, Pires WL, Felipin KP, Ferreira GEM, Bozza PT, Zuliani JP. Cytosolic phospholipase A 2-α participates in lipid body formation and PGE 2 release in human neutrophils stimulated with an L-amino acid oxidase from Calloselasma rhodostoma venom. Sci Rep 2020; 10:10976. [PMID: 32620771 DOI: 10.1038/s41598-020-67345-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 06/05/2020] [Indexed: 12/02/2022] Open
Abstract
Cr-LAAO, an l-amino acid oxidase isolated from Calloselasma rhodosthoma snake venom, has been demonstrated as a potent stimulus for neutrophil activation and inflammatory mediator production. However, the mechanisms involved in Cr-LAAO induced neutrophil activation has not been well characterized. Here we investigated the mechanisms involved in Cr-LAAO-induced lipid body (also known as lipid droplet) biogenesis and eicosanoid formation in human neutrophils. Using microarray analysis, we show for the first time that Cr-LAAO plays a role in the up-regulation of the expression of genes involved in lipid signalling and metabolism. Those include different members of phospholipase A2, mostly cytosolic phospholipase A2-α (cPLA2-α); and enzymes involved in prostaglandin synthesis including cyclooxygenases 2 (COX-2), and prostaglandin E synthase (PTGES). In addition, genes involved in lipid droplet formation, including perilipin 2 and 3 (PLIN 2 and 3) and diacylglycerol acyltransferase 1 (DGAT1), were also upregulated. Furthermore, increased phosphorylation of cPLA2-α, lipid droplet biogenesis and PGE2 synthesis were observed in human neutrophils stimulated with Cr-LAAO. Treatment with cPLA2-α inhibitor (CAY10650) or DGAT-1 inhibitor (A922500) suppressed lipid droplets formation and PGE2 secretion. In conclusion, we demonstrate for the first time the effects of Cr-LAAO to regulate neutrophil lipid metabolism and signalling.
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30
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Veliova M, Petcherski A, Liesa M, Shirihai OS. The biology of lipid droplet-bound mitochondria. Semin Cell Dev Biol 2020; 108:55-64. [PMID: 32446655 DOI: 10.1016/j.semcdb.2020.04.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 04/17/2020] [Accepted: 04/18/2020] [Indexed: 12/12/2022]
Abstract
Proper regulation of cellular lipid storage and oxidation is indispensable for the maintenance of cellular energy homeostasis and health. Mitochondrial function has been shown to be a main determinant of functional lipid storage and oxidation, which is of particular interest for the adipose tissue, as it is the main site of triacylglyceride storage in lipid droplets (LDs). Recent studies have identified a subpopulation of mitochondria attached to LDs, peridroplet mitochondria (PDM) that can be separated from cytoplasmic mitochondria (CM) by centrifugation. PDM have distinct bioenergetics, proteome, cristae organization and dynamics that support LD build-up, however their role in adipose tissue biology remains largely unexplored. Therefore, understanding the molecular basis of LD homeostasis and their relationship to mitochondrial function and attachment in adipocytes is of major importance.
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31
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Abstract
Thermogenesis is the production of heat that occurs in all warm-blooded animals. During cold exposure, there is obligatory thermogenesis derived from body metabolism as well as adaptive thermogenesis through shivering and non-shivering mechanisms. The latter mainly occurs in brown adipose tissue (BAT) and muscle; however, white adipose tissue (WAT) also can undergo browning via adrenergic stimulation to acquire thermogenic potential. Thyroid hormone (TH) also exerts profound effects on thermoregulation, as decreased body temperature and increased body temperature occur during hypothyroidism and hyperthyroidism, respectively. We have termed the TH-mediated thermogenesis under thermoneutral conditions “activated” thermogenesis. TH acts on the brown and/or white adipose tissues to induce uncoupled respiration through the induction of the uncoupling protein (Ucp1) to generate heat. TH acts centrally to activate the BAT and browning through the sympathetic nervous system. However, recent studies also show that TH acts peripherally on the BAT to directly stimulate Ucp1 expression and thermogenesis through an autophagy-dependent mechanism. Additionally, THs can exert Ucp1-independent effects on thermogenesis, most likely through activation of exothermic metabolic pathways. This review summarizes thermogenic effects of THs on adipose tissues.
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Affiliation(s)
- Winifred W Yau
- Laboratory of Hormonal Regulation, Cardiovascular and Metabolic Disorders Program, Duke NUS Medical School, Singapore 169857, Singapore
| | - Paul M Yen
- Laboratory of Hormonal Regulation, Cardiovascular and Metabolic Disorders Program, Duke NUS Medical School, Singapore 169857, Singapore
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27708, USA
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32
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McGivney BA, Han H, Corduff LR, Katz LM, Tozaki T, MacHugh DE, Hill EW. Genomic inbreeding trends, influential sire lines and selection in the global Thoroughbred horse population. Sci Rep 2020; 10:466. [PMID: 31949252 PMCID: PMC6965197 DOI: 10.1038/s41598-019-57389-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/30/2019] [Indexed: 02/07/2023] Open
Abstract
The Thoroughbred horse is a highly valued domestic animal population under strong selection for athletic phenotypes. Here we present a high resolution genomics-based analysis of inbreeding in the population that may form the basis for evidence-based discussion amid concerns in the breeding industry over the increasing use of small numbers of popular sire lines, which may accelerate a loss of genetic diversity. In the most comprehensive globally representative sample of Thoroughbreds to-date (n = 10,118), including prominent stallions (n = 305) from the major bloodstock regions of the world, we show using pan-genomic SNP genotypes that there has been a highly significant decline in global genetic diversity during the last five decades (FIS R2 = 0.942, P = 2.19 × 10-13; FROH R2 = 0.88, P = 1.81 × 10-10) that has likely been influenced by the use of popular sire lines. Estimates of effective population size in the global and regional populations indicate that there is some level of regional variation that may be exploited to improve global genetic diversity. Inbreeding is often a consequence of selection, which in managed animal populations tends to be driven by preferences for cultural, aesthetic or economically advantageous phenotypes. Using a composite selection signals approach, we show that centuries of selection for favourable athletic traits among Thoroughbreds acts on genes with functions in behaviour, musculoskeletal conformation and metabolism. As well as classical selective sweeps at core loci, polygenic adaptation for functional modalities in cardiovascular signalling, organismal growth and development, cellular stress and injury, metabolic pathways and neurotransmitters and other nervous system signalling has shaped the Thoroughbred athletic phenotype. Our results demonstrate that genomics-based approaches to identify genetic outcrosses will add valuable objectivity to augment traditional methods of stallion selection and that genomics-based methods will be beneficial to actively monitor the population to address the marked inbreeding trend.
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Affiliation(s)
| | - Haige Han
- Plusvital Ltd, The Highline, Dun Laoghaire Business Park, Dublin, Ireland
- UCD School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Leanne R Corduff
- Plusvital Ltd, The Highline, Dun Laoghaire Business Park, Dublin, Ireland
| | - Lisa M Katz
- UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Teruaki Tozaki
- Genetic Analysis Department, Laboratory of Racing Chemistry, Utsunomiya, Tochigi, Japan
| | - David E MacHugh
- UCD School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
- UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Emmeline W Hill
- Plusvital Ltd, The Highline, Dun Laoghaire Business Park, Dublin, Ireland.
- UCD School of Agriculture and Food Science, University College Dublin, Dublin, Ireland.
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33
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Løvsletten NG, Vu H, Skagen C, Lund J, Kase ET, Thoresen GH, Zammit VA, Rustan AC. Treatment of human skeletal muscle cells with inhibitors of diacylglycerol acyltransferases 1 and 2 to explore isozyme-specific roles on lipid metabolism. Sci Rep 2020; 10:238. [PMID: 31937853 PMCID: PMC6959318 DOI: 10.1038/s41598-019-57157-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 12/19/2019] [Indexed: 12/30/2022] Open
Abstract
Diacylglycerol acyltransferases (DGAT) 1 and 2 catalyse the final step in triacylglycerol (TAG) synthesis, the esterification of fatty acyl-CoA to diacylglycerol. Despite catalysing the same reaction and being present in the same cell types, they exhibit different functions on lipid metabolism in various tissues. Yet, their roles in skeletal muscle remain poorly defined. In this study, we investigated how selective inhibitors of DGAT1 and DGAT2 affected lipid metabolism in human primary skeletal muscle cells. The results showed that DGAT1 was dominant in human skeletal muscle cells utilizing fatty acids (FAs) derived from various sources, both exogenously supplied FA, de novo synthesised FA, or FA derived from lipolysis, to generate TAG, as well as being involved in de novo synthesis of TAG. On the other hand, DGAT2 seemed to be specialised for de novo synthesis of TAG from glycerol-3-posphate only. Interestingly, DGAT activities were also important for regulating FA oxidation, indicating a key role in balancing FAs between storage in TAG and efficient utilization through oxidation. Finally, we observed that inhibition of DGAT enzymes could potentially alter glucose-FA interactions in skeletal muscle. In summary, treatment with DGAT1 or DGAT2 specific inhibitors resulted in different responses on lipid metabolism in human myotubes, indicating that the two enzymes play distinct roles in TAG metabolism in skeletal muscle.
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Affiliation(s)
- Nils G Løvsletten
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Helene Vu
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Christine Skagen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Jenny Lund
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - Eili T Kase
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway
| | - G Hege Thoresen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway.,Department of Pharmacology, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Victor A Zammit
- Division of Translational and Experimental medicine, Warwick Medical School, University of Warwick, Coventry, UK
| | - Arild C Rustan
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway.
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34
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Henne M, Goodman JM, Hariri H. Spatial compartmentalization of lipid droplet biogenesis. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158499. [PMID: 31352131 PMCID: PMC7050823 DOI: 10.1016/j.bbalip.2019.07.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 07/08/2019] [Accepted: 07/09/2019] [Indexed: 12/18/2022]
Abstract
Lipid droplets (LDs) are ubiquitous organelles that store metabolic energy in the form of neutral lipids (typically triacylglycerols and steryl esters). Beyond being inert energy storage compartments, LDs are dynamic organelles that participate in numerous essential metabolic functions. Cells generate LDs de novo from distinct sub-regions at the endoplasmic reticulum (ER), but what determines sites of LD formation remains a key unanswered question. Here, we review the factors that determine LD formation at the ER, and discuss how they work together to spatially and temporally coordinate LD biogenesis. These factors include lipid synthesis enzymes, assembly proteins, and membrane structural requirements. LDs also make contact with other organelles, and these inter-organelle contacts contribute to defining sites of LD production. Finally, we highlight emerging non-canonical roles for LDs in maintaining cellular homeostasis during stress.
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Affiliation(s)
- Mike Henne
- Department of Cell Biology and Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Joel M Goodman
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Hanaa Hariri
- Department of Cell Biology and Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, United States of America.
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35
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Abstract
Our understanding of brown adipose tissue (BAT) function in humans has increased rapidly over the past 10 years. This is predominantly due to the development of powerful non-invasive imaging techniques such as positron emission tomography that can quantify BAT mass and function using metabolic tracers. Activation of BAT during cold-induced thermogenesis is an effective way to dissipate energy to generate heat and requires utilization of multiple energy substrates for optimal function. This has led to interest in the activation of BAT as a potential therapeutic target for type 2 diabetes, dyslipidaemia, and obesity. Here, we provide an overview of the current understanding of BAT substrate utilization in humans and highlight additional mechanisms found in rodents, where BAT more prominently contributes to energy expenditure. During thermogenesis, BAT demonstrates substantially increased glucose uptake which appears to be critical for BAT function. However, glucose is not fully oxidized, with a large proportion converted to lactate. The primary energy substrate for thermogenesis is fatty acids, released from brown adipocyte triglyceride stores. Active BAT also sequesters circulating lipids to sustain optimal thermogenesis. Recent evidence reveals that metabolic intermediates from the tricarboxylic acid cycle and glycolytic pathways also play a critical role in BAT function. Understanding the role of these metabolites in regulating thermogenesis and whole body substrate utilization may elucidate novel strategies for therapeutic BAT activation.
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36
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Otyama PI, Wilkey A, Kulkarni R, Assefa T, Chu Y, Clevenger J, O'Connor DJ, Wright GC, Dezern SW, MacDonald GE, Anglin NL, Cannon EKS, Ozias-Akins P, Cannon SB. Evaluation of linkage disequilibrium, population structure, and genetic diversity in the U.S. peanut mini core collection. BMC Genomics 2019; 20:481. [PMID: 31185892 PMCID: PMC6558826 DOI: 10.1186/s12864-019-5824-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 05/21/2019] [Indexed: 12/03/2022] Open
Abstract
Background Due to the recent domestication of peanut from a single tetraploidization event, relatively little genetic diversity underlies the extensive morphological and agronomic diversity in peanut cultivars today. To broaden the genetic variation in future breeding programs, it is necessary to characterize germplasm accessions for new sources of variation and to leverage the power of genome-wide association studies (GWAS) to discover markers associated with traits of interest. We report an analysis of linkage disequilibrium (LD), population structure, and genetic diversity, and examine the ability of GWA to infer marker-trait associations in the U.S. peanut mini core collection genotyped with a 58 K SNP array. Results LD persists over long distances in the collection, decaying to r2 = half decay distance at 3.78 Mb. Structure within the collection is best explained when separated into four or five groups (K = 4 and K = 5). At K = 4 and 5, accessions loosely clustered according to market type and subspecies, though with numerous exceptions. Out of 107 accessions, 43 clustered in correspondence to the main market type subgroup whereas 34 did not. The remaining 30 accessions had either missing taxonomic classification or were classified as mixed. Phylogenetic network analysis also clustered accessions into approximately five groups based on their genotypes, with loose correspondence to subspecies and market type. Genome wide association analysis was performed on these lines for 12 seed composition and quality traits. Significant marker associations were identified for arachidic and behenic fatty acid compositions, which despite having low bioavailability in peanut, have been reported to raise cholesterol levels in humans. Other traits such as blanchability showed consistent associations in multiple tests, with plausible candidate genes. Conclusions Based on GWA, population structure as well as additional simulation results, we find that the primary limitations of this collection for GWAS are a small collection size, significant remaining structure/genetic similarity and long LD blocks that limit the resolution of association mapping. These results can be used to improve GWAS in peanut in future studies – for example, by increasing the size and reducing structure in the collections used for GWAS. Electronic supplementary material The online version of this article (10.1186/s12864-019-5824-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Paul I Otyama
- Agronomy Department, Iowa State University, Ames, IA, USA
| | - Andrew Wilkey
- ORISE Fellow, Corn Insects and Crop Genetics Research Unit, USDA-ARS, Ames, IA, USA
| | - Roshan Kulkarni
- Agronomy Department, Iowa State University, Ames, IA, USA.,ORISE Fellow, Corn Insects and Crop Genetics Research Unit, USDA-ARS, Ames, IA, USA
| | - Teshale Assefa
- Agronomy Department, Iowa State University, Ames, IA, USA.,ORISE Fellow, Corn Insects and Crop Genetics Research Unit, USDA-ARS, Ames, IA, USA
| | - Ye Chu
- Institute of Plant Breeding, Genetics, and Genomics, University of Georgia, Tifton, GA, USA
| | - Josh Clevenger
- Mars-Wrigley Confectionery, Center for Applied Genetic Technologies, Athens, GA, USA
| | | | | | | | | | | | | | - Peggy Ozias-Akins
- Institute of Plant Breeding, Genetics, and Genomics, University of Georgia, Tifton, GA, USA
| | - Steven B Cannon
- Corn Insects and Crop Genetics Research Unit, USDA - Agricultural Research Service, 1017 Crop Genome Lab 819 Wallace Rd, Ames, IA, 50011-4014, USA.
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Grandoch M, Flögel U, Virtue S, Maier JK, Jelenik T, Kohlmorgen C, Feldmann K, Ostendorf Y, Castañeda TR, Zhou Z, Yamaguchi Y, Nascimento EB, Sunkari VG, Goy C, Kinzig M, Sörgel F, Bollyky PL, Schrauwen P, Al-Hasani H, Roden M, Keipert S, Vidal-Puig A, Jastroch M, Haendeler J, Fischer JW. 4-Methylumbelliferone improves the thermogenic capacity of brown adipose tissue. Nat Metab 2019; 1:546-559. [PMID: 31602424 PMCID: PMC6786893 DOI: 10.1038/s42255-019-0055-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Therapeutic increase of brown adipose tissue (BAT) thermogenesis is of great interest as BAT activation counteracts obesity and insulin resistance. Hyaluronan (HA) is a glycosaminoglycan, found in the extracellular matrix, which is synthesized by HA synthases (Has1/Has2/Has3) from sugar precursors and accumulates in diabetic conditions. Its synthesis can be inhibited by the small molecule 4-methylumbelliferone (4-MU). Here, we show that the inhibition of HA-synthesis by 4-MU or genetic deletion of Has2/Has3 improves BAT`s thermogenic capacity, reduces body weight gain, and improves glucose homeostasis independently from adrenergic stimulation in mice on diabetogenic diet, as shown by a magnetic resonance T2 mapping approach. Inhibition of HA synthesis increases glycolysis, BAT respiration and uncoupling protein 1 expression. In addition, we show that 4-MU increases BAT capacity without inducing chronic stimulation and propose that 4-MU, a clinically approved prescription-free drug, could be repurposed to treat obesity and diabetes.
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Affiliation(s)
- Maria Grandoch
- Institute of Pharmacology and Clinical Pharmacology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- corresponding author: Dr. Maria Grandoch, Institute of Pharmacology and Clinical Pharmacology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany,
| | - Ulrich Flögel
- Experimental Cardiovascular Imaging, Molecular Cardiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Sam Virtue
- MRC Metabolic Diseases Unit, Metabolic Research Laboratories, University of Cambridge, Cambridge, United Kingdom
| | - Julia K. Maier
- Institute of Pharmacology and Clinical Pharmacology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Tomas Jelenik
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at the Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), München-Neuherberg, Germany
| | - Christina Kohlmorgen
- Institute of Pharmacology and Clinical Pharmacology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Kathrin Feldmann
- Institute of Pharmacology and Clinical Pharmacology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Yanina Ostendorf
- Institute of Pharmacology and Clinical Pharmacology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Tamara R. Castañeda
- German Center for Diabetes Research (DZD e.V.), München-Neuherberg, Germany
- Institute for Clinical Biochemistry and Pathobiochemistry, Medical Faculty, German Diabetes Center, Leibniz Center for Diabetes Research at the Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Zhou Zhou
- German Center for Diabetes Research (DZD e.V.), München-Neuherberg, Germany
- Institute for Clinical Biochemistry and Pathobiochemistry, Medical Faculty, German Diabetes Center, Leibniz Center for Diabetes Research at the Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Yu Yamaguchi
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Emmani B.M. Nascimento
- Department of Nutrition and Movement Sciences, Maastricht Medical Centre, NUTRIM School of Nutrition and Translational Research in Metabolism, The Netherlands
| | - Vivekananda G. Sunkari
- Division of Infectious Diseases and Geographic Medicine, Dept. of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Christine Goy
- Institute for Clinical Chemistry, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Martina Kinzig
- Institute for Biomedical and Pharmaceutical Research, Nürnberg-Heroldsberg, Germany
| | - Fritz Sörgel
- Institute for Biomedical and Pharmaceutical Research, Nürnberg-Heroldsberg, Germany
| | - Paul L. Bollyky
- Division of Infectious Diseases and Geographic Medicine, Dept. of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Patrick Schrauwen
- Department of Nutrition and Movement Sciences, Maastricht Medical Centre, NUTRIM School of Nutrition and Translational Research in Metabolism, The Netherlands
| | - Hadi Al-Hasani
- German Center for Diabetes Research (DZD e.V.), München-Neuherberg, Germany
- Institute for Clinical Biochemistry and Pathobiochemistry, Medical Faculty, German Diabetes Center, Leibniz Center for Diabetes Research at the Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Michael Roden
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at the Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), München-Neuherberg, Germany
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Susanne Keipert
- German Center for Diabetes Research (DZD e.V.), München-Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Antonio Vidal-Puig
- MRC Metabolic Diseases Unit, Metabolic Research Laboratories, University of Cambridge, Cambridge, United Kingdom
- WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Martin Jastroch
- German Center for Diabetes Research (DZD e.V.), München-Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Judith Haendeler
- Institute for Clinical Chemistry, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- IUF - Leibniz Research Institute for Environmental Medicine, Heisenberg Group - Environmentally-induced Cardiovascular Degeneration, Düsseldorf, Germany
| | - Jens W. Fischer
- Institute of Pharmacology and Clinical Pharmacology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
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Zhang X, Zhang CC, Yang H, Soni KG, Wang SP, Mitchell GA, Wu JW. An Epistatic Interaction between Pnpla2 and Lipe Reveals New Pathways of Adipose Tissue Lipolysis. Cells 2019; 8:cells8050395. [PMID: 31035700 PMCID: PMC6563012 DOI: 10.3390/cells8050395] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/17/2019] [Accepted: 04/23/2019] [Indexed: 12/20/2022] Open
Abstract
White adipose tissue (WAT) lipolysis contributes to energy balance during fasting. Lipolysis can proceed by the sequential hydrolysis of triglycerides (TGs) by adipose triglyceride lipase (ATGL), then of diacylglycerols (DGs) by hormone-sensitive lipase (HSL). We showed that the combined genetic deficiency of ATGL and HSL in mouse adipose tissue produces a striking different phenotype from that of isolated ATGL deficiency, inconsistent with the linear model of lipolysis. We hypothesized that the mechanism might be functional redundancy between ATGL and HSL. To test this, the TG hydrolase activity of HSL was measured in WAT. HSL showed TG hydrolase activity. Then, to test ATGL for activity towards DGs, radiolabeled DGs were incubated with HSL-deficient lipid droplet fractions. The content of TG increased, suggesting DG-to-TG synthesis rather than DG hydrolysis. TG synthesis was abolished by a specific ATGL inhibitor, suggesting that ATGL functions as a transacylase when HSL is deficient, transferring an acyl group from one DG to another, forming a TG plus a monoglyceride (MG) that could be hydrolyzed by monoglyceride lipase. These results reveal a previously unknown physiological redundancy between ATGL and HSL, a mechanism for the epistatic interaction between Pnpla2 and Lipe. It provides an alternative lipolytic pathway, potentially important in patients with deficient lipolysis.
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Affiliation(s)
- Xiao Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
| | - Cong Cong Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
| | - Hao Yang
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal, QC H3T 1C5, Canada.
| | - Krishnakant G Soni
- Section of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX 77030, USA.
| | - Shu Pei Wang
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal, QC H3T 1C5, Canada.
| | - Grant A Mitchell
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal, QC H3T 1C5, Canada.
| | - Jiang Wei Wu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
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Abstract
Brown adipose tissue (BAT) is proposed to maintain thermal homeostasis through dissipation of chemical energy as heat by the uncoupling proteins (UCPs) present in their mitochondria. The recent demonstration of the presence of BAT in humans has invigorated research in this area. The research has provided many new insights into the biology and functioning of this tissue and the biological implications of its altered activities. Another finding of interest is browning of white adipose tissue (WAT) resulting in what is known as beige/brite cells, which have increased mitochondrial proteins and UCPs. In general, it has been observed that the activation of BAT is associated with various physiological improvements such as a reduction in blood glucose levels increased resting energy expenditure and reduced weight. Given the similar physiological functions of BAT and beige/ brite cells and the higher mass of WAT compared to BAT, it is likely that increasing the brite/beige cells in WATs may also lead to greater metabolic benefits. However, development of treatments targeting brown fat or WAT browning would require not only a substantial understanding of the biology of these tissues but also the effect of altering their activity levels on whole body metabolism and physiology. In this review, we present evidence from recent literature on the substrates utilized by BAT, regulation of BAT activity and browning by circulating molecules. We also present dietary and pharmacological activators of brown and beige/brite adipose tissue and the effect of physical exercise on BAT activity and browning.
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Affiliation(s)
- Shireesh Srivastava
- Systems Biology for Biofuels Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Richard L Veech
- Laboratory of Metabolic Control, National Institute on Alcohol Abuse and Alcoholism (NIAAA), National Institutes of Health (NIH), Bethesda, MD, United States
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40
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Abreu-Vieira G, Sardjoe Mishre ASD, Burakiewicz J, Janssen LGM, Nahon KJ, van der Eijk JA, Riem TT, Boon MR, Dzyubachyk O, Webb AG, Rensen PCN, Kan HE. Human Brown Adipose Tissue Estimated With Magnetic Resonance Imaging Undergoes Changes in Composition After Cold Exposure: An in vivo MRI Study in Healthy Volunteers. Front Endocrinol (Lausanne) 2019; 10:898. [PMID: 31998233 PMCID: PMC6964318 DOI: 10.3389/fendo.2019.00898] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/09/2019] [Indexed: 01/02/2023] Open
Abstract
Aim: Magnetic resonance imaging (MRI) is increasingly being used to evaluate brown adipose tissue (BAT) function. Reports on the extent and direction of cold-induced changes in MRI fat fraction and estimated BAT volume vary between studies. Here, we aimed to explore the effect of different fat fraction threshold ranges on outcomes measured by MRI. Moreover, we aimed to investigate the effect of cold exposure on estimated BAT mass and energy content. Methods: The effects of cold exposure at different fat fraction thresholding levels were analyzed in the supraclavicular adipose depot of nine adult males. MRI data were reconstructed, co-registered and analyzed in two ways. First, we analyzed cold-induced changes in fat fraction, T2* relaxation time, volume, mass, and energy of the entire supraclavicular adipose depot at different fat fraction threshold levels. As a control, we assessed fat fraction differences of deltoid subcutaneous adipose tissue (SAT). Second, a local analysis was performed to study changes in fat fraction and T2* on a voxel-level. Thermoneutral and post-cooling data were compared using paired-sample t-tests (p < 0.05). Results: Global analysis unveiled that the largest cold-induced change in fat fraction occurred within a thermoneutral fat fraction range of 30-100% (-3.5 ± 1.9%), without changing the estimated BAT volume. However, the largest cold-induced changes in estimated BAT volume were observed when applying a thermoneutral fat fraction range of 70-100% (-3.8 ± 2.6%). No changes were observed for the deltoid SAT fat fractions. Tissue energy content was reduced from 126 ± 33 to 121 ± 30 kcal, when using a 30-100% fat fraction range, and also depended on different fat fraction thresholds. Voxel-wise analysis showed that while cold exposure changed the fat fraction across nearly all thermoneutral fat fractions, decreases were most pronounced at high thermoneutral fat fractions. Conclusion: Cold-induced changes in fat fraction occurred over the entire range of thermoneutral fat fractions, and were especially found in lipid-rich regions of the supraclavicular adipose depot. Due to the variability in response between lipid-rich and lipid-poor regions, care should be taken when applying fat fraction thresholds for MRI BAT analysis.
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Affiliation(s)
- Gustavo Abreu-Vieira
- Division of Endocrinology and Einthoven Laboratory for Experimental Vascular Medicine, Department of Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Aashley S. D. Sardjoe Mishre
- Division of Endocrinology and Einthoven Laboratory for Experimental Vascular Medicine, Department of Medicine, Leiden University Medical Center, Leiden, Netherlands
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands
| | - Jedrzej Burakiewicz
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands
| | - Laura G. M. Janssen
- Division of Endocrinology and Einthoven Laboratory for Experimental Vascular Medicine, Department of Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Kimberly J. Nahon
- Division of Endocrinology and Einthoven Laboratory for Experimental Vascular Medicine, Department of Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Jari A. van der Eijk
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands
| | - Titia T. Riem
- Division of Endocrinology and Einthoven Laboratory for Experimental Vascular Medicine, Department of Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Mariëtte R. Boon
- Division of Endocrinology and Einthoven Laboratory for Experimental Vascular Medicine, Department of Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Oleh Dzyubachyk
- Division of Image Processing (LKEB), Department of Radiology, Leiden University Medical Center, Leiden, Netherlands
| | - Andrew G. Webb
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands
| | - Patrick C. N. Rensen
- Division of Endocrinology and Einthoven Laboratory for Experimental Vascular Medicine, Department of Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Hermien E. Kan
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands
- *Correspondence: Hermien E. Kan
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41
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Irshad Z, Chmel N, Adya R, Zammit VA. Hepatic VLDL secretion: DGAT1 determines particle size but not particle number, which can be supported entirely by DGAT2. J Lipid Res 2018; 60:111-120. [PMID: 30397187 PMCID: PMC6314258 DOI: 10.1194/jlr.m089300] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 10/08/2018] [Indexed: 12/25/2022] Open
Abstract
We investigated whether, in view of its activity being expressed on both aspects of the endoplasmic reticulum (ER; dual membrane topology), diacylglycerol acyltransferase 1 (DGAT1) plays a distinctive role in determining the triglyceride (TAG) content of VLDL particles secreted by the liver. Mice in which the DGAT1 gene was specifically ablated in hepatocytes (DGAT1-LKO mice) had the same number of VLDL particles (apoB concentration) in the plasma 1 h after Triton 1339 treatment, but these particles were approximately half the size of VLDL particles secreted by control mice and had a proportionately decreased content of TAG, with normal cholesterol and cholesteryl ester contents. Analyses of purified microsomal fractions prepared from 16 h fasted control and DAGT1-LKO mice showed that the TAG/protein ratio in the ER was significantly lower in the latter. Electron micrographs of these livers showed that those from DGAT1-LKO mice did not show the increased lipid content of the smooth ER shown by control livers. The effects of DGAT1- and DGAT2-specific inhibitors on apoB secretion by HepG2 cells showed that DGAT1 is not indispensable for apoB secretion and demonstrated redundancy in the ability of the two enzymes to support apoB secretion. Therefore, our findings show that DGAT1 is essential for the complete lipidation and maturation of VLDL particles within the lumen of the ER, consistent with its dual topology within the ER membrane. In the mouse, DGAT2 can support apoB secretion (particle number) even when TAG availability for full VLDL lipidation is restricted in the absence of DGAT1.
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Affiliation(s)
- Zehra Irshad
- Translational and Experimental Medicine, Warwick Medical School, Coventry CV4 7AL, United Kingdom
| | - Nikola Chmel
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Raghu Adya
- Translational and Experimental Medicine, Warwick Medical School, Coventry CV4 7AL, United Kingdom
| | - Victor A Zammit
- Translational and Experimental Medicine, Warwick Medical School, Coventry CV4 7AL, United Kingdom
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Hankir MK, Klingenspor M. Brown adipocyte glucose metabolism: a heated subject. EMBO Rep 2018; 19:embr.201846404. [PMID: 30135070 DOI: 10.15252/embr.201846404] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 06/22/2018] [Accepted: 07/20/2018] [Indexed: 11/09/2022] Open
Abstract
The energy expending and glucose sink properties of brown adipose tissue (BAT) make it an attractive target for new obesity and diabetes treatments. Despite decades of research, only recently have mechanistic studies started to provide a more complete and consistent picture of how activated brown adipocytes handle glucose. Here, we discuss the importance of intracellular glycolysis, lactate production, lipogenesis, lipolysis, and beta-oxidation for BAT thermogenesis in response to natural (temperature) and artificial (pharmacological and optogenetic) forms of sympathetic nervous system stimulation. It is now clear that together, these metabolic processes in series and in parallel flexibly power ATP-dependent and independent futile cycles in brown adipocytes to impact on whole-body thermal, energy, and glucose balance.
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Affiliation(s)
- Mohammed K Hankir
- Department of Experimental Surgery, University Hospital Wuerzburg, Wuerzburg, Germany .,German Research Foundation Collaborative Research Center in Obesity Mechanisms 1052, University of Leipzig, Leipzig, Germany
| | - Martin Klingenspor
- Chair of Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany .,EKFZ - Else Kröner-Fresenius Center for Nutritional Medicine, Technical University of Munich, Freising, Germany
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43
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Musso G, Cassader M, Paschetta E, Gambino R. Bioactive Lipid Species and Metabolic Pathways in Progression and Resolution of Nonalcoholic Steatohepatitis. Gastroenterology 2018; 155:282-302.e8. [PMID: 29906416 DOI: 10.1053/j.gastro.2018.06.031] [Citation(s) in RCA: 194] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 05/30/2018] [Accepted: 06/01/2018] [Indexed: 02/06/2023]
Abstract
The prevalence of nonalcoholic steatohepatitis (NASH) is increasing worldwide, yet there are no effective treatments. A decade has passed since the initial lipidomics analyses of liver tissues from patients with nonalcoholic fatty liver disease. We have learned that liver cells from patients with NASH have an abnormal lipid composition and that the accumulation of lipids leads to organelle dysfunction, cell injury and death, and chronic inflammation, called lipotoxicity. We review the lipid species and metabolic pathways that contribute to the pathogenesis of NASH and potential therapeutic targets, including enzymes involved in fatty acid and triglyceride synthesis, bioactive sphingolipids and polyunsaturated-derived eicosanoids, and specialized pro-resolving lipid mediators. We discuss the concept that NASH is a disease that can resolve and the roles of lipid molecules in the resolution of inflammation and regression of fibrosis.
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Affiliation(s)
| | - Maurizio Cassader
- Department of Medical Sciences, San Giovanni Battista Hospital, University of Turin, Turin, Italy
| | | | - Roberto Gambino
- Department of Medical Sciences, San Giovanni Battista Hospital, University of Turin, Turin, Italy
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44
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Ruiz JR, Martinez-Tellez B, Sanchez-Delgado G, Osuna-Prieto FJ, Rensen PCN, Boon MR. Role of Human Brown Fat in Obesity, Metabolism and Cardiovascular Disease: Strategies to Turn Up the Heat. Prog Cardiovasc Dis 2018; 61:232-245. [PMID: 29981351 DOI: 10.1016/j.pcad.2018.07.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 07/01/2018] [Indexed: 11/17/2022]
Abstract
Human brown adipose tissue (BAT) was re-discovered in 2009 by several independent groups, who showed that it is present and active in adults, as judged from the profound uptake of the glucose analogue radiotracer 18F-fluorodeoxyglucose in positron-emission tomography and computed tomography scan analysis after cold exposure. A potential clinical implication of activating BAT relates to its high metabolic activity and its potential role in stimulating energy expenditure (i.e. resting energy expenditure, meal-induced thermogenesis, and cold-induced thermogenesis), which makes it an attractive target to reduce adiposity. Moreover, due to its ability to oxidise glucose and lipids, BAT activation may also potentially exert beneficial metabolic and cardiovascular effects through reducing glucose and lipid levels, respectively. This review describes the potential role of human BAT in the prevention and treatment of obesity, metabolism, and cardiovascular disease focusing on its impact on energy expenditure and management of body fat accumulation as well as on glucose and lipid metabolism. This article also summarises the strategies that are currently being studied to activate human BAT.
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Affiliation(s)
- Jonatan R Ruiz
- PROFITH (PROmoting FITness and Health through Physical Activity) Research Group, Department of Physical and Sports Education, Faculty of Sports Science, University of Granada, Granada, Spain.
| | - Borja Martinez-Tellez
- PROFITH (PROmoting FITness and Health through Physical Activity) Research Group, Department of Physical and Sports Education, Faculty of Sports Science, University of Granada, Granada, Spain; Department of Medicine, Division of Endocrinology, Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Guillermo Sanchez-Delgado
- PROFITH (PROmoting FITness and Health through Physical Activity) Research Group, Department of Physical and Sports Education, Faculty of Sports Science, University of Granada, Granada, Spain
| | - Francisco J Osuna-Prieto
- PROFITH (PROmoting FITness and Health through Physical Activity) Research Group, Department of Physical and Sports Education, Faculty of Sports Science, University of Granada, Granada, Spain; Department of Analytical Chemistry, University of Granada, Avda Fuentenueva s/n, 18071 Granada, Spain; Research and Development of Functional Food Centre (CIDAF), Granada, Spain
| | - Patrick C N Rensen
- Department of Medicine, Division of Endocrinology, Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Mariëtte R Boon
- Department of Medicine, Division of Endocrinology, Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
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Held NM, Kuipers EN, van Weeghel M, van Klinken JB, Denis SW, Lombès M, Wanders RJ, Vaz FM, Rensen PCN, Verhoeven AJ, Boon MR, Houtkooper RH. Pyruvate dehydrogenase complex plays a central role in brown adipocyte energy expenditure and fuel utilization during short-term beta-adrenergic activation. Sci Rep 2018; 8:9562. [PMID: 29934543 DOI: 10.1038/s41598-018-27875-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 06/12/2018] [Indexed: 12/27/2022] Open
Abstract
Activation of brown adipose tissue (BAT) contributes to total body energy expenditure through energy dissipation as heat. Activated BAT increases the clearance of lipids and glucose from the circulation, but how BAT accommodates large influx of multiple substrates is not well defined. The purpose of this work was to assess the metabolic fluxes in brown adipocytes during β3-adrenergic receptor (β3-AR) activation.T37i murine preadipocytes were differentiated into brown adipocytes and we used Seahorse respirometry employing a set of specific substrate inhibitors in the presence or absence of β3-AR agonist CL316,243. The main substrate used by these brown adipocytes were fatty acids, which were oxidized equally during activation as well as during resting condition. [U-13C]-glucose tracer-based metabolomics revealed that the flux through the TCA cycle was enhanced and regulated by pyruvate dehydrogenase (PDH) activity. Based on 13C-tracer incorporation in lipids, it appeared that most glucose was oxidized via TCA cycle activity, while some was utilized for glycerol-3-phosphate synthesis to replenish the triglyceride pool. Collectively, we show that while fatty acids are the main substrates for oxidation, glucose is also oxidized to meet the increased energy demand during short term β3-AR activation. PDH plays an important role in directing glucose carbons towards oxidation.
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Abstract
PURPOSE OF REVIEW This article explores how the interplay between lipid metabolism and thermogenic adipose tissues enables proper physiological adaptation to cold environments in rodents and humans. RECENT FINDINGS Cold exposure triggers systemic changes in lipid metabolism, which increases fatty acid delivery to brown adipose tissue (BAT) by various routes. Next to fatty acids generated intracellularly by de-novo lipogenesis or by lipolysis at lipid droplets, brown adipocytes utilize fatty acids released by white adipose tissue (WAT) for adaptive thermogenesis. WAT-derived fatty acids are internalized directly by BAT, or indirectly after hepatic conversion to very low-density lipoproteins and acylcarnitines. In the postprandial state, chylomicrons hydrolyzed by lipoprotein lipase - activated specifically in thermogenic adipocytes - are the predominant fatty acid source. Cholesterol-enriched chylomicron remnants and HDL generated by intravascular lipolysis in BAT are cleared more rapidly by the liver, explaining the antiatherogenic effects of BAT activation. Notably, increased cholesterol flux and elevated hepatic synthesis of bile acids under cold exposure further promote BAT-dependent thermogenesis. SUMMARY Although pathways providing fatty acids for activated BAT have been identified, more research is needed to understand the integration of lipid metabolism in BAT, WAT and liver, and to determine the relevance of BAT for human energy metabolism.
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Affiliation(s)
- Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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47
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Steensels S, Ersoy BA. Fatty acid activation in thermogenic adipose tissue. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:79-90. [PMID: 29793055 DOI: 10.1016/j.bbalip.2018.05.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 03/10/2018] [Accepted: 05/17/2018] [Indexed: 02/07/2023]
Abstract
Channeling carbohydrates and fatty acids to thermogenic tissues, including brown and beige adipocytes, have garnered interest as an approach for the management of obesity-related metabolic disorders. Mitochondrial fatty acid oxidation (β-oxidation) is crucial for the maintenance of thermogenesis. Upon cellular fatty acid uptake or following lipolysis from triglycerides (TG), fatty acids are esterified to coenzyme A (CoA) to form active acyl-CoA molecules. This enzymatic reaction is essential for their utilization in β-oxidation and thermogenesis. The activation and deactivation of fatty acids are regulated by two sets of enzymes called acyl-CoA synthetases (ACS) and acyl-CoA thioesterases (ACOT), respectively. The expression levels of ACS and ACOT family members in thermogenic tissues will determine the substrate availability for β-oxidation, and consequently the thermogenic capacity. Although the role of the majority of ACS and ACOT family members in thermogenesis remains unclear, recent proceedings link the enzymatic activities of ACS and ACOT family members to metabolic disorders and thermogenesis. Elucidating the contributions of specific ACS and ACOT family members to trafficking of fatty acids towards thermogenesis may reveal novel targets for modulating thermogenic capacity and treating metabolic disorders.
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Affiliation(s)
- Sandra Steensels
- Department of Medicine, Division of Gastroenterology and Hepatology, Weill Cornell Medical College, New York, NY, USA
| | - Baran A Ersoy
- Department of Medicine, Division of Gastroenterology and Hepatology, Weill Cornell Medical College, New York, NY, USA.
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48
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Chechi K, van Marken Lichtenbelt W, Richard D. Brown and beige adipose tissues: phenotype and metabolic potential in mice and men. J Appl Physiol (1985) 2018; 124:482-496. [PMID: 28302705 PMCID: PMC5867364 DOI: 10.1152/japplphysiol.00021.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/09/2017] [Accepted: 03/13/2017] [Indexed: 01/06/2023] Open
Abstract
With the recent rediscovery of brown fat in adult humans, our outlook on adipose tissue biology has undergone a paradigm shift. While we attempt to identify, recruit, and activate classic brown fat stores in humans, identification of beige fat has also raised the possibility of browning our white fat stores. Whether such transformation of human white fat depots can be achieved to enhance the whole body oxidative potential remains to be seen. Evidence to date, however, largely points toward a major oxidative role only for classic brown fat depots, at least in rodents. White fat stores seem to provide the main fuel for sustaining thermogenesis via lipolysis. Interestingly, molecular markers consistent with both classic brown and beige fat identity can be observed in human supraclavicular depot, thereby complicating the discussion on beige fat in humans. Here, we review the recent advances made in our understanding of brown and beige fat in humans and mice. We further provide an overview of their plausible physiological relevance to whole body energy metabolism.
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Affiliation(s)
- Kanta Chechi
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Ville de Québec, Quebec , Canada
| | - Wouter van Marken Lichtenbelt
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center , Maastricht , The Netherlands
| | - Denis Richard
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Ville de Québec, Quebec , Canada
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49
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Abstract
Brown adipose tissue (BAT) is specialized to both store and expend chemical energy making it an ideal therapeutic target for various metabolic diseases. Fatty acids derived from lipid droplets within brown adipocytes acting on mitochondrial uncoupling protein 1 (UCP1) were long thought to be essential for non-shivering thermogenesis. Here, the roles of white adipose tissue and the liver in the provision of fuel to BAT as part of a coordinated response to temperature and dietary challenges are described. UCP1-independent modes of brown adipocyte heat production are also highlighted. A model that accommodates the findings obtained so far is further presented in which according to the conditions imposed on brown adipocytes, the relative contributions of circulating lipids and glucose for their normal function varies. Gaining deeper insight into the molecular processes which poise brown adipocytes to protect against whole-body thermal and energy imbalance represents a promising future area of metabolic research.
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Affiliation(s)
- Mohammed K. Hankir
- Department of Experimental Surgery, University Hospital Wuerzburg, Wuerzburg, Bavaria, Germany
- German Research Foundation Collaborative Research Center in Obesity Mechanisms, University of Leipzig, Leipzig, Saxony, Germany
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50
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Abstract
Lipid droplets (LDs) are ubiquitous organelles that store neutral lipids for energy or membrane synthesis and act as hubs for metabolic processes. Cells generate LDs de novo, converting cells to emulsions with LDs constituting the dispersed oil phase in the aqueous cytoplasm. Here we review our current view of LD biogenesis. We present a model of LD formation from the ER in distinct steps and highlight the biology of proteins that govern this biophysical process. Areas of incomplete knowledge are identified, as are connections with physiology and diseases linked to alterations in LD biology.
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Affiliation(s)
- Tobias C Walther
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115; , .,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115.,Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142.,Howard Hughes Medical Institute, Boston, Massachusetts 02115
| | - Jeeyun Chung
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115; , .,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Robert V Farese
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115; , .,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115.,Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142
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