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Valentine C, Ohnishi K, Irie K, Murakami A. Curcumin may induce lipolysis via proteo-stress in Huh7 human hepatoma cells. J Clin Biochem Nutr 2019; 65:91-98. [PMID: 31592057 DOI: 10.3164/jcbn.19-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 05/02/2019] [Indexed: 12/25/2022] Open
Abstract
Curcumin has been shown to have anti-obesity effects in animal studies. Although several molecular mechanisms of action have been reported, the initial or upstream molecular events remain to be revealed. In this study, we found that curcumin or heat shock treatment up-regulated the expression of adipose triglyceride lipase (ATGL) in Huh7 hepatoma cells, which resulted in acceleration of lipolysis. Interestingly, perturbation of protein homeostasis was seen in curcumin-treated cells, as detected by formation of numerous ubiquitinated proteins and conjugated proteins with p62 (SQSTM). Curcumin activated the protein expression of molecular chaperones, such as heat shock protein (HSP)40 and HSP70. Pre-treatment of the cells with 4-phenylbutyric acid, a chemical chaperone, suppressed proteo-stress induced by curcumin and reduced its lipolysis effect. Importantly, the cytotoxicity of curcumin was markedly alleviated when intracellular triglyceride was consumed by the polyphenol. Thus, energy supplementation from lipolysis may play substantial roles in adaptation and survival of curcumin-exposed cells. To support this notion, the cytotoxicity of curcumin was aggravated in ATGL-knockdown cells. Curcumin decreased intracellular ATP for activating AMP-activated protein kinase, which initiates catabolic pathways including ATGL-dependent lipolysis. Taken together, we propose a hypothesis that curcumin induces lipolysis to compensate for ATP reduction due to its proteo-stress effects.
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Affiliation(s)
- Cindy Valentine
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kohta Ohnishi
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kazuhiro Irie
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Akira Murakami
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
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52
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Koo SJ, Garg NJ. Metabolic programming of macrophage functions and pathogens control. Redox Biol 2019; 24:101198. [PMID: 31048245 PMCID: PMC6488820 DOI: 10.1016/j.redox.2019.101198] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 04/09/2019] [Indexed: 12/15/2022] Open
Abstract
Macrophages (Mφ) are central players in mediating proinflammatory and immunomodulatory functions. Unchecked Mφ activities contribute to pathology across many diseases, including those caused by infectious pathogens and metabolic disorders. A fine balance of Mφ responses is crucial, which may be achieved by enforcing appropriate bioenergetics pathways. Metabolism serves as the provider of energy, substrates, and byproducts that support differential Mφ characteristics. The metabolic properties that control the polarization and response of Mφ remain to be fully uncovered for use in managing infectious diseases. Here, we review the various metabolic states in Mφ and how they influence the cell function.
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Affiliation(s)
- Sue-Jie Koo
- Department of Pathology, University of Texas Medical Branch (UTMB), Galveston, TX, USA
| | - Nisha J Garg
- Department of Microbiology & Immunology, UTMB, Galveston, TX, USA; Institute for Human Infections and Immunity, UTMB, Galveston, TX, USA.
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53
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Zhang S, Weinberg S, DeBerge M, Gainullina A, Schipma M, Kinchen JM, Ben-Sahra I, Gius DR, Yvan-Charvet L, Chandel NS, Schumacker PT, Thorp EB. Efferocytosis Fuels Requirements of Fatty Acid Oxidation and the Electron Transport Chain to Polarize Macrophages for Tissue Repair. Cell Metab 2019; 29:443-456.e5. [PMID: 30595481 PMCID: PMC6471613 DOI: 10.1016/j.cmet.2018.12.004] [Citation(s) in RCA: 236] [Impact Index Per Article: 47.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 09/22/2018] [Accepted: 11/30/2018] [Indexed: 10/27/2022]
Abstract
During wound injury, efferocytosis fills the macrophage with a metabolite load nearly equal to the phagocyte itself. A timely question pertains to how metabolic phagocytic signaling regulates the signature anti-inflammatory macrophage response. Here we report the metabolome of activated macrophages during efferocytosis to reveal an interleukin-10 (IL-10) cytokine escalation that was independent of glycolysis yet bolstered by apoptotic cell fatty acids and mitochondrial β-oxidation, the electron transport chain, and heightened coenzyme NAD+. Loss of IL-10 due to mitochondrial complex III defects was remarkably rescued by adding NAD+ precursors. This activated a SIRTUIN1 signaling cascade, largely independent of ATP, that culminated in activation of IL-10 transcription factor PBX1. Il-10 activation by the respiratory chain was also important in vivo, as efferocyte mitochondrial dysfunction led to cardiac rupture after myocardial injury. These findings highlight a new paradigm whereby macrophages leverage efferocytic metabolites and electron transport for anti-inflammatory reprogramming that culminates in organ repair.
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Affiliation(s)
- Shuang Zhang
- Department of Pathology, Feinberg School of Medicine, Chicago, IL, USA; Feinberg Cardiovascular & Renal Research Institute, Feinberg School of Medicine, Chicago, IL, USA
| | - Samuel Weinberg
- Department of Medicine, Feinberg School of Medicine, Chicago, IL, USA
| | - Matthew DeBerge
- Department of Pathology, Feinberg School of Medicine, Chicago, IL, USA; Feinberg Cardiovascular & Renal Research Institute, Feinberg School of Medicine, Chicago, IL, USA
| | - Anastasiia Gainullina
- ITMO University, Saint Petersburg, Russia; Washington University in St. Louis, St. Louis, MO, USA
| | - Matthew Schipma
- Feinberg Cardiovascular & Renal Research Institute, Feinberg School of Medicine, Chicago, IL, USA
| | | | - Issam Ben-Sahra
- Department of Pharmacology, Feinberg School of Medicine, Chicago, IL, USA
| | - David R Gius
- Department of Radiation Oncology, Feinberg School of Medicine, Chicago, IL, USA
| | - Laurent Yvan-Charvet
- Institut National de la Sante et de la Recherche Medicale (INSERM) U1065, Centre Mediterraneen de Medecine Moleculaire (C3M), Atip-Avenir, Nice, France
| | - Navdeep S Chandel
- Department of Medicine, Feinberg School of Medicine, Chicago, IL, USA
| | - Paul T Schumacker
- Department of Pediatrics, Feinberg School of Medicine, Chicago, IL, USA
| | - Edward B Thorp
- Department of Pathology, Feinberg School of Medicine, Chicago, IL, USA; Feinberg Cardiovascular & Renal Research Institute, Feinberg School of Medicine, Chicago, IL, USA.
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54
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Chen H, Huang Y, Yang P, Liu T, Ahmed N, Wang L, Wang T, Bai X, Haseeb A, Chen Q. Lipophagy contributes to long-term storage of spermatozoa in the epididymis of the Chinese soft-shelled turtle Pelodiscus sinensis. Reprod Fertil Dev 2019; 31:774-786. [DOI: 10.1071/rd18307] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 11/09/2018] [Indexed: 12/19/2022] Open
Abstract
Spermatozoa are known to be stored in the epididymis of the Chinese soft-shelled turtle Pelodiscus sinensis for long periods after spermiation from the testes, but the molecular mechanisms underlying this storage are largely unknown. In this study, epididymal spermatozoa were investigated to determine the potential molecular mechanism for long-term sperm storage in P. sinensis. Transmission electron microscopy (TEM) and Oil red O staining indicated that unusually large cytoplasmic droplets containing lipid droplets (LDs) were attached to the epididymal spermatozoa. However, the content of LDs decreased gradually with the sperm storage. LDs were surrounded by autophagic vesicles and sequestered as degradative cargo within autophagosome. Immunofluorescence and western blotting demonstrated that autophagy in spermatozoa increased gradually with the storage time. Invitro studies found that spermatozoa obtained from soft-shelled turtles in January can survive more than 40 days at 4°C. Furthermore, immunofluorescence and TEM showed that autophagy was involved in the degradation of LDs with the extension of sperm incubation. Inhibition of autophagy with 3-methyladenine significantly suppressed LD degradation. Moreover, adipose triglyceride lipase was involved in the metabolism of LDs. These findings indicate that lipophagy was activated to maximise LD breakdown, which contributes to long-term sperm storage in the epididymis of P. sinensis.
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Of mice and men: The physiological role of adipose triglyceride lipase (ATGL). Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:880-899. [PMID: 30367950 PMCID: PMC6439276 DOI: 10.1016/j.bbalip.2018.10.008] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 12/12/2022]
Abstract
Adipose triglyceride lipase (ATGL) has been discovered 14 years ago and revised our view on intracellular triglyceride (TG) mobilization – a process termed lipolysis. ATGL initiates the hydrolysis of TGs to release fatty acids (FAs) that are crucial energy substrates, precursors for the synthesis of membrane lipids, and ligands of nuclear receptors. Thus, ATGL is a key enzyme in whole-body energy homeostasis. In this review, we give an update on how ATGL is regulated on the transcriptional and post-transcriptional level and how this affects the enzymes' activity in the context of neutral lipid catabolism. In depth, we highlight and discuss the numerous physiological functions of ATGL in lipid and energy metabolism. Over more than a decade, different genetic mouse models lacking or overexpressing ATGL in a cell- or tissue-specific manner have been generated and characterized. Moreover, pharmacological studies became available due to the development of a specific murine ATGL inhibitor (Atglistatin®). The identification of patients with mutations in the human gene encoding ATGL and their disease spectrum has underpinned the importance of ATGL in humans. Together, mouse models and human data have advanced our understanding of the physiological role of ATGL in lipid and energy metabolism in adipose and non-adipose tissues, and of the pathophysiological consequences of ATGL dysfunction in mice and men. Summary of mouse models with genetic or pharmacological manipulation of ATGL. Summary of patients with mutations in the human gene encoding ATGL. In depth discussion of the role of ATGL in numerous physiological processes in mice and men.
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56
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Nadjar A. Role of metabolic programming in the modulation of microglia phagocytosis by lipids. Prostaglandins Leukot Essent Fatty Acids 2018; 135:63-73. [PMID: 30103935 DOI: 10.1016/j.plefa.2018.07.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 07/11/2018] [Accepted: 07/11/2018] [Indexed: 02/06/2023]
Abstract
Microglia phagocytosis is an essential process to maintain lifelong brain homeostasis and clear potential toxic factors from the neuropil. Microglia can engulf cells or part of cells through the expression of specific receptors at their surface and activation of downstream signaling pathways to engulf material. Microglia phagocytosis is finely regulated and is under the dependence of many factors, including environmental cues such as dietary lipids. Yet, the molecular mechanisms implicated are still largely unknown. The present publication is a 'hypothesis review', assessing the possibility that lipid-mediated modulation of phagocytosis occurs by affecting bioenergetic pathways within microglia. I assess our present knowledge and the elements that allow drawing such hypothesis. I also list some of the important gaps in the literature that need to be filled in. I also consider opportunities for future therapeutic target including nutritional interventions.
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Affiliation(s)
- A Nadjar
- INRA, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux 33076, France; University Bordeaux, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux 33076, France.
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57
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Trépanier MO, Hopperton KE, Giuliano V, Masoodi M, Bazinet RP. Increased brain docosahexaenoic acid has no effect on the resolution of neuroinflammation following intracerebroventricular lipopolysaccharide injection. Neurochem Int 2018; 118:115-126. [PMID: 29792954 DOI: 10.1016/j.neuint.2018.05.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/17/2018] [Accepted: 05/21/2018] [Indexed: 12/31/2022]
Abstract
Resolution of inflammation in the periphery was once thought to be a passive process, but new research now suggests it is an active process mediated by specialized pro-resolving lipid mediators (SPM) derived from omega-3 polyunsaturated fatty acids (n-3 PUFA). However, this has yet to be illustrated in neuroinflammation. The purpose of this study was to measure resolution of neuroinflammation and to test whether increasing brain docosahexaenoic acid (DHA) affects the resolution of neuroinflammation. C57Bl/6 mice, fat-1 mice and their wildtype littermates, fed either fish oil or safflower oil, received lipopolysaccharide (LPS) in the left lateral ventricle. Animals were then euthanized at various time points for immunohistochemistry, gene expression, and lipidomic analyses. Peak microglial activation was observed at 5 days post-surgery and the resolution index was 10 days. Of the approximately 350 genes significantly changed over the 28 days post LPS injection, 130 were uniquely changed at 3 days post injection. No changes were observed in the bioactive mediator pools. However, a few lysophospholipid species were decreased at 24hr post surgery. When brain DHA is increased, microglial cell density did not resolve faster and did not alter gene expression. In conclusion, resolution of neuroinflammation appears to be independent of SPM. Increasing brain DHA had no effect in this model.
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Affiliation(s)
- Marc-Olivier Trépanier
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, M5S 3E2, Canada
| | - Kathryn E Hopperton
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, M5S 3E2, Canada
| | - Vanessa Giuliano
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, M5S 3E2, Canada
| | - Mojgan Masoodi
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, M5S 3E2, Canada; Lipid Biology, Nestlé Institute of Health Sciences, CH-1015 Lausanne, Switzerland
| | - Richard P Bazinet
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, M5S 3E2, Canada.
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58
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Henne WM, Reese ML, Goodman JM. The assembly of lipid droplets and their roles in challenged cells. EMBO J 2018; 37:embj.201898947. [PMID: 29789390 DOI: 10.15252/embj.201898947] [Citation(s) in RCA: 171] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 03/08/2018] [Accepted: 03/22/2018] [Indexed: 12/14/2022] Open
Abstract
Cytoplasmic lipid droplets are important organelles in nearly every eukaryotic and some prokaryotic cells. Storing and providing energy is their main function, but they do not work in isolation. They respond to stimuli initiated either on the cell surface or in the cytoplasm as conditions change. Cellular stresses such as starvation and invasion are internal insults that evoke changes in droplet metabolism and dynamics. This review will first outline lipid droplet assembly and then discuss how droplets respond to stress and in particular nutrient starvation. Finally, the role of droplets in viral and microbial invasion will be presented, where an unresolved issue is whether changes in droplet abundance promote the invader, defend the host, to try to do both. The challenges of stress and infection are often accompanied by changes in physical contacts between droplets and other organelles. How these changes may result in improving cellular physiology, an ongoing focus in the field, is discussed.
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Affiliation(s)
- W Mike Henne
- Department of Cell Biology, University of Texas Southwestern Medical School, Dallas, TX, USA
| | - Michael L Reese
- Department of Pharmacology, University of Texas Southwestern Medical School, Dallas, TX, USA
| | - Joel M Goodman
- Department of Pharmacology, University of Texas Southwestern Medical School, Dallas, TX, USA
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59
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Hints on ATGL implications in cancer: beyond bioenergetic clues. Cell Death Dis 2018; 9:316. [PMID: 29472527 PMCID: PMC5833653 DOI: 10.1038/s41419-018-0345-z] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/22/2018] [Accepted: 01/23/2018] [Indexed: 12/21/2022]
Abstract
Among metabolic rearrangements occurring in cancer cells, lipid metabolism alteration has become a hallmark, aimed at sustaining accelerated proliferation. In particular, fatty acids (FAs) are dramatically required by cancer cells as signalling molecules and membrane building blocks, beyond bioenergetics. Along with de novo biosynthesis, free FAs derive from dietary sources or from intracellular lipid droplets, which represent the storage of triacylglycerols (TAGs). Adipose triglyceride lipase (ATGL) is the rate-limiting enzyme of lipolysis, catalysing the first step of intracellular TAGs hydrolysis in several tissues. However, the roles of ATGL in cancer are still neglected though a putative tumour suppressor function of ATGL has been envisaged, as its expression is frequently reduced in different human cancers (e.g., lung, muscle, and pancreas). In this review, we will introduce lipid metabolism focusing on ATGL functions and regulation in normal cell physiology providing also speculative perspectives on potential non-energetic functions of ATGL in cancer. In particular, we will discuss how ATGL is implicated, mainly through the peroxisome proliferator-activated receptor-α (PPAR-α) signalling, in inflammation, redox homoeostasis and autophagy, which are well-known processes deregulated during cancer formation and/or progression.
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60
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Duta-Mare M, Sachdev V, Leopold C, Kolb D, Vujic N, Korbelius M, Hofer DC, Xia W, Huber K, Auer M, Gottschalk B, Magnes C, Graier WF, Prokesch A, Radovic B, Bogner-Strauss JG, Kratky D. Lysosomal acid lipase regulates fatty acid channeling in brown adipose tissue to maintain thermogenesis. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:467-478. [PMID: 29374543 DOI: 10.1016/j.bbalip.2018.01.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 01/02/2018] [Accepted: 01/22/2018] [Indexed: 02/07/2023]
Abstract
Lysosomal acid lipase (LAL) is the only known enzyme, which hydrolyzes cholesteryl esters and triacylglycerols in lysosomes of multiple cells and tissues. Here, we explored the role of LAL in brown adipose tissue (BAT). LAL-deficient (Lal-/-) mice exhibit markedly reduced UCP1 expression in BAT, modified BAT morphology with accumulation of lysosomes, and mitochondrial dysfunction, consequently leading to regular hypothermic events in mice kept at room temperature. Cold exposure resulted in reduced lipid uptake into BAT, thereby aggravating dyslipidemia and causing life threatening hypothermia in Lal-/- mice. Linking LAL as a potential regulator of lipoprotein lipase activity, we found Angptl4 mRNA expression upregulated in BAT. Our data demonstrate that LAL is critical for shuttling fatty acids derived from circulating lipoproteins to BAT during cold exposure. We conclude that inhibited lysosomal lipid hydrolysis in BAT leads to impaired thermogenesis in Lal-/- mice.
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Affiliation(s)
- Madalina Duta-Mare
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Vinay Sachdev
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Christina Leopold
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Dagmar Kolb
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria; Center for Medical Research, Medical University of Graz, Graz, Austria
| | - Nemanja Vujic
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Melanie Korbelius
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Dina C Hofer
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Wenmin Xia
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Katharina Huber
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Martina Auer
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | | | - Christoph Magnes
- Health, Bioanalytik und Metabolomics, Joanneum Research, Graz, Austria
| | - Wolfgang F Graier
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Andreas Prokesch
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Branislav Radovic
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Juliane G Bogner-Strauss
- Institute of Biochemistry, Graz University of Technology, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria.
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61
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Zechner R, Madeo F, Kratky D. Cytosolic lipolysis and lipophagy: two sides of the same coin. Nat Rev Mol Cell Biol 2017; 18:671-684. [DOI: 10.1038/nrm.2017.76] [Citation(s) in RCA: 258] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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62
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Critical roles for α/β hydrolase domain 5 (ABHD5)/comparative gene identification-58 (CGI-58) at the lipid droplet interface and beyond. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1233-1241. [PMID: 28827091 DOI: 10.1016/j.bbalip.2017.07.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 07/24/2017] [Accepted: 07/31/2017] [Indexed: 01/04/2023]
Abstract
Mutations in the gene encoding comparative gene identification 58 (CGI-58), also known as α β hydrolase domain-containing 5 (ABHD5), cause neutral lipid storage disorder with ichthyosis (NLSDI). This inborn error in metabolism is characterized by ectopic accumulation of triacylglycerols (TAG) within cytoplasmic lipid droplets in multiple cell types. Studies over the past decade have clearly demonstrated that CGI-58 is a potent regulator of TAG hydrolysis in the disease-relevant cell types. However, despite the reproducible genetic link between CGI-58 mutations and TAG storage, the molecular mechanisms by which CGI-58 regulates TAG hydrolysis are still incompletely understood. It is clear that CGI-58 can regulate TAG hydrolysis by activating the major TAG hydrolase adipose triglyceride lipase (ATGL), yet CGI-58 can also regulate lipid metabolism via mechanisms that do not involve ATGL. This review highlights recent progress made in defining the physiologic and biochemical function of CGI-58, and its broader role in energy homeostasis. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
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63
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Unfolded protein response signaling impacts macrophage polarity to modulate breast cancer cell clearance and melanoma immune checkpoint therapy responsiveness. Oncotarget 2017; 8:80545-80559. [PMID: 29113324 PMCID: PMC5655219 DOI: 10.18632/oncotarget.19849] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 07/23/2017] [Indexed: 12/28/2022] Open
Abstract
The unfolded protein response (UPR) is a stress pathway controlled by GRP78 to mediate IRE1, PERK, and ATF6 signaling. We show that targeting GRP78, IRE1, and PERK differentially regulates macrophage polarization. Specifically, PERK targeting enhanced macrophage proliferation and macrophage-mediated killing but not GRP78 or IRE1. Targeting UPR in cancer cells also differentially affected macrophage cytolytic capacity. Tumoral IRE1 or GRP78 inhibition enhanced macrophage-mediated cancer cell clearance. Conditioned media from GRP78-silenced cancer cells caused reciprocal regulation of CD80 and CD206, suggesting control of plasticity by secreted factors. GRP78 targeting in mice resulted in a cytokine shift and increased tumoral CD80+/CD68+ cells, suggesting an M1-like profile. Targeting UPR in both macrophage and cancer cells indicates that PERK or GRP78 reduction enhances macrophage clearance of cancer cells. Recent evidence suggests that macrophage polarization influences immune checkpoint therapy resistance. To determine whether UPR effects immunotherapy resistance, analysis of matched melanoma patient PBMC before/after developing ipilimumab resistance demonstrated increased UPR signaling and an M2-like macrophage population, supporting a novel role of UPR signaling and innate immune regulation in anti-CTLA-4 therapy resistance. These data suggest that targeting GRP78 or PERK promotes an anti-tumor immune response by either directly promoting macrophage cytolytic activity or indirectly by shifting tumoral cytokine secretion.
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64
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Bolsoni-Lopes A, Alonso-Vale MIC. Lipolysis and lipases in white adipose tissue - An update. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2017; 59:335-42. [PMID: 26331321 DOI: 10.1590/2359-3997000000067] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 04/22/2015] [Indexed: 11/22/2022]
Abstract
Lipolysis is defined as the sequential hydrolysis of triacylglycerol (TAG) stored in cell lipid droplets. For many years, it was believed that hormone-sensitive lipase (HSL) and monoacylglycerol lipase (MGL) were the main enzymes catalyzing lipolysis in the white adipose tissue. Since the discovery of adipose triglyceride lipase (ATGL) in 2004, many studies were performed to investigate and characterize the actions of this lipase, as well as of other proteins and possible regulatory mechanisms involved, which reformulated the concept of lipolysis. Novel findings from these studies include the identification of lipolytic products as signaling molecules regulating important metabolic processes in many non-adipose tissues, unveiling a previously underestimated aspect of lipolysis. Thus, we present here an updated review of concepts and regulation of white adipocyte lipolysis with a special emphasis in its role in metabolism homeostasis and as a source of important signaling molecules.
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Affiliation(s)
- Andressa Bolsoni-Lopes
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, BR
| | - Maria Isabel C Alonso-Vale
- Departamento de Ciências Biológicas, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, SP, BR
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65
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Rombaldova M, Janovska P, Kopecky J, Kuda O. Omega-3 fatty acids promote fatty acid utilization and production of pro-resolving lipid mediators in alternatively activated adipose tissue macrophages. Biochem Biophys Res Commun 2017; 490:1080-1085. [PMID: 28668396 DOI: 10.1016/j.bbrc.2017.06.170] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 12/31/2022]
Abstract
It is becoming increasingly apparent that mutual interactions between adipocytes and immune cells are key to the integrated control of adipose tissue inflammation and lipid metabolism in obesity, but little is known about the non-inflammatory functions of adipose tissue macrophages (ATMs) and how they might be impacted by neighboring adipocytes. In the current study we used metabolipidomic analysis to examine the adaptations to lipid overload of M1 or M2 polarized macrophages co-incubated with adipocytes and explored potential benefits of omega-3 polyunsaturated fatty acids (PUFA). Macrophages adjust their metabolism to process excess lipids and M2 macrophages in turn modulate lipolysis and fatty acids (FA) re-esterification of adipocytes. While M1 macrophages tend to store surplus FA as triacylglycerols and cholesteryl esters in lipid droplets, M2 macrophages channel FA toward re-esterification and β-oxidation. Dietary omega-3 PUFA enhance β-oxidation in both M1 and M2. Our data document that ATMs contribute to lipid trafficking in adipose tissue and that omega-3 PUFA could modulate FA metabolism of ATMs.
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Affiliation(s)
- Martina Rombaldova
- Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Videnska 1083, 14220 Praha 4, Czech Republic; Charles University in Prague, Faculty of Science, Department of Analytical Chemistry, Albertov 2030, 128 43 Prague, Czech Republic
| | - Petra Janovska
- Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Videnska 1083, 14220 Praha 4, Czech Republic
| | - Jan Kopecky
- Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Videnska 1083, 14220 Praha 4, Czech Republic
| | - Ondrej Kuda
- Department of Adipose Tissue Biology, Institute of Physiology of the Czech Academy of Sciences, Videnska 1083, 14220 Praha 4, Czech Republic.
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66
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Hu X, Binns D, Reese ML. The coccidian parasites Toxoplasma and Neospora dysregulate mammalian lipid droplet biogenesis. J Biol Chem 2017; 292:11009-11020. [PMID: 28487365 DOI: 10.1074/jbc.m116.768176] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 05/05/2017] [Indexed: 11/06/2022] Open
Abstract
Upon infection, the intracellular parasite Toxoplasma gondii co-opts critical functions of its host cell to avoid immune clearance and gain access to nutritional resources. One route by which Toxoplasma co-opts its host cell is through hijacking host organelles, many of which have roles in immunomodulation. Here we demonstrate that Toxoplasma infection results in increased biogenesis of host lipid droplets through rewiring of multiple components of host neutral lipid metabolism. These metabolic changes cause increased responsiveness of host cells to free fatty acid, leading to a radical increase in the esterification of free fatty acids into triacylglycerol. We identified c-Jun kinase and mammalian target of rapamycin (mTOR) as components of two distinct host signaling pathways that modulate the parasite-induced lipid droplet accumulation. We also found that, unlike many host processes dysregulated during Toxoplasma infection, the induction of lipid droplet generation is conserved not only during infection with genetically diverse Toxoplasma strains but also with Neospora caninum, which is closely related to Toxoplasma but has a restricted host range and uses different effector proteins to alter host signaling. Finally, by showing that a Toxoplasma strain deficient in exporting a specific class of effectors is unable to induce lipid droplet accumulation, we demonstrate that the parasite plays an active role in this process. These results indicate that, despite their different host ranges, Toxoplasma and Neospora use a conserved mechanism to co-opt these host organelles, which suggests that lipid droplets play a critical role at the coccidian host-pathogen interface.
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Affiliation(s)
- Xiaoyu Hu
- From the Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041
| | - Derk Binns
- From the Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041
| | - Michael L Reese
- From the Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041
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67
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Gonzalez-Hurtado E, Lee J, Choi J, Selen Alpergin ES, Collins SL, Horton MR, Wolfgang MJ. Loss of macrophage fatty acid oxidation does not potentiate systemic metabolic dysfunction. Am J Physiol Endocrinol Metab 2017; 312:E381-E393. [PMID: 28223293 PMCID: PMC5451524 DOI: 10.1152/ajpendo.00408.2016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 02/02/2017] [Accepted: 02/14/2017] [Indexed: 12/21/2022]
Abstract
Fatty acid oxidation in macrophages has been suggested to play a causative role in high-fat diet-induced metabolic dysfunction, particularly in the etiology of adipose-driven insulin resistance. To understand the contribution of macrophage fatty acid oxidation directly to metabolic dysfunction in high-fat diet-induced obesity, we generated mice with a myeloid-specific knockout of carnitine palmitoyltransferase II (CPT2 Mϕ-KO), an obligate step in mitochondrial long-chain fatty acid oxidation. While fatty acid oxidation was clearly induced upon IL-4 stimulation, fatty acid oxidation-deficient CPT2 Mϕ-KO bone marrow-derived macrophages displayed canonical markers of M2 polarization following IL-4 stimulation in vitro. In addition, loss of macrophage fatty acid oxidation in vivo did not alter the progression of high-fat diet-induced obesity, inflammation, macrophage polarization, oxidative stress, or glucose intolerance. These data suggest that although IL-4-stimulated alternatively activated macrophages upregulate fatty acid oxidation, fatty acid oxidation is dispensable for macrophage polarization and high-fat diet-induced metabolic dysfunction. Macrophage fatty acid oxidation likely plays a correlative, rather than causative, role in systemic metabolic dysfunction.
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Affiliation(s)
- Elsie Gonzalez-Hurtado
- Department of Biological Chemistry, Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Jieun Lee
- Department of Biological Chemistry, Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Joseph Choi
- Department of Biological Chemistry, Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Ebru S Selen Alpergin
- Department of Biological Chemistry, Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Samuel L Collins
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Maureen R Horton
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Michael J Wolfgang
- Department of Biological Chemistry, Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland; and
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68
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Mahapatra E, Dasgupta D, Bhattacharya N, Mitra S, Banerjee D, Goswami S, Ghosh N, Dey A, Chakraborty S. Sustaining immunity during starvation in bivalve mollusc: A costly affair. Tissue Cell 2017; 49:239-248. [DOI: 10.1016/j.tice.2017.02.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 02/17/2017] [Accepted: 02/17/2017] [Indexed: 01/04/2023]
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69
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MURAKAMI M. Lipoquality control by phospholipase A 2 enzymes. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2017; 93:677-702. [PMID: 29129849 PMCID: PMC5743847 DOI: 10.2183/pjab.93.043] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The phospholipase A2 (PLA2) family comprises a group of lipolytic enzymes that typically hydrolyze the sn-2 position of glycerophospholipids to give rise to fatty acids and lysophospholipids. The mammalian genome encodes more than 50 PLA2s or related enzymes, which are classified into several subfamilies on the basis of their structures and functions. From a general viewpoint, the PLA2 family has mainly been implicated in signal transduction, producing bioactive lipid mediators derived from fatty acids and lysophospholipids. Recent evidence indicates that PLA2s also contribute to phospholipid remodeling for membrane homeostasis or energy production for fatty acid β-oxidation. Accordingly, PLA2 enzymes can be regarded as one of the key regulators of the quality of lipids, which I herein refer to as lipoquality. Disturbance of PLA2-regulated lipoquality hampers tissue and cellular homeostasis and can be linked to various diseases. Here I overview the current state of understanding of the classification, enzymatic properties, and physiological functions of the PLA2 family.
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Affiliation(s)
- Makoto MURAKAMI
- Laboratory of Environmental and Metabolic Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
- AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, Japan
- Correspondence should be addressed: M. Murakami, Laboratory of Environmental and Metabolic Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan (e-mail: )
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70
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Lachmandas E, Boutens L, Ratter JM, Hijmans A, Hooiveld GJ, Joosten LAB, Rodenburg RJ, Fransen JAM, Houtkooper RH, van Crevel R, Netea MG, Stienstra R. Microbial stimulation of different Toll-like receptor signalling pathways induces diverse metabolic programmes in human monocytes. Nat Microbiol 2016; 2:16246. [PMID: 27991883 DOI: 10.1038/nmicrobiol.2016.246] [Citation(s) in RCA: 189] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 11/04/2016] [Indexed: 01/16/2023]
Abstract
Microbial stimuli such as lipopolysaccharide (LPS) induce robust metabolic rewiring in immune cells known as the Warburg effect. It is unknown whether this increase in glycolysis and decrease in oxidative phosphorylation (OXPHOS) is a general characteristic of monocytes that have encountered a pathogen. Using CD14+ monocytes from healthy donors, we demonstrated that most microbial stimuli increased glycolysis, but that only stimulation of Toll-like receptor (TLR) 4 with LPS led to a decrease in OXPHOS. Instead, activation of other TLRs, such as TLR2 activation by Pam3CysSK4 (P3C), increased oxygen consumption and mitochondrial enzyme activity. Transcriptome and metabolome analysis of monocytes stimulated with P3C versus LPS confirmed the divergent metabolic responses between both stimuli, and revealed significant differences in the tricarboxylic acid cycle, OXPHOS and lipid metabolism pathways following stimulation of monocytes with P3C versus LPS. At a functional level, pharmacological inhibition of complex I of the mitochondrial electron transport chain diminished cytokine production and phagocytosis in P3C- but not LPS-stimulated monocytes. Thus, unlike LPS, complex microbial stimuli and the TLR2 ligand P3C induce a specific pattern of metabolic rewiring that involves upregulation of both glycolysis and OXPHOS, which enables activation of host defence mechanisms such as cytokine production and phagocytosis.
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Affiliation(s)
- Ekta Lachmandas
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands
| | - Lily Boutens
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands.,Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, 6708 WE, Wageningen, The Netherlands
| | - Jacqueline M Ratter
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands.,Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, 6708 WE, Wageningen, The Netherlands
| | - Anneke Hijmans
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands
| | - Guido J Hooiveld
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, 6708 WE, Wageningen, The Netherlands
| | - Leo A B Joosten
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands
| | - Richard J Rodenburg
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, 774 Translational Metabolic Laboratory, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands
| | - Jack A M Fransen
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 1105 AZ, Nijmegen, The Netherlands
| | - Riekelt H Houtkooper
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, 1105 AZ, Amsterdam, The Netherlands
| | - Reinout van Crevel
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands
| | - Mihai G Netea
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands
| | - Rinke Stienstra
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands.,Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, 6708 WE, Wageningen, The Netherlands
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71
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Lykov AP, Korolenko TA, Sakhno LV, Poveshchenko OV, Bondarenko NA, Surovtseva MA, Goncharova NV. Effects of Anti-CD206 Antibodies on Macrophage Functions in Male CBF1 Mice with Lipidemia. Bull Exp Biol Med 2016; 162:237-239. [PMID: 27909959 DOI: 10.1007/s10517-016-3584-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Indexed: 10/20/2022]
Abstract
The effects of anti-CD208 antibodies (mannose receptor) on functional characteristics of peritoneal macrophages were studied in intact mice and mice with lipidemia induced by poloxamer-407. Lipidemia was associated with suppression of phagocytosis and increase in spontaneous proliferative potential and NO production by macrophages. Anti-CD206 antibodies suppressed NO production by macrophages in mice with lipidemia.
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Affiliation(s)
- A P Lykov
- Research Institute of Clinical and Experimental Lymphology, Novosibirsk, Russia.
| | - T A Korolenko
- Research Institute of Physiology and Fundamental Medicine, Novosibirsk, Russia
| | - L V Sakhno
- Institute of Fundamental and Clinical Immunology, Novosibirsk, Russia
| | - O V Poveshchenko
- Research Institute of Clinical and Experimental Lymphology, Novosibirsk, Russia
| | - N A Bondarenko
- Research Institute of Clinical and Experimental Lymphology, Novosibirsk, Russia
| | - M A Surovtseva
- Research Institute of Clinical and Experimental Lymphology, Novosibirsk, Russia
| | - N V Goncharova
- Research Institute of Physiology and Fundamental Medicine, Novosibirsk, Russia
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72
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Khalifeh-Soltani A, Gupta D, Ha A, Iqbal J, Hussain M, Podolsky MJ, Atabai K. Mfge8 regulates enterocyte lipid storage by promoting enterocyte triglyceride hydrolase activity. JCI Insight 2016; 1:e87418. [PMID: 27812539 DOI: 10.1172/jci.insight.87418] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The small intestine has an underappreciated role as a lipid storage organ. Under conditions of high dietary fat intake, enterocytes can minimize the extent of postprandial lipemia by storing newly absorbed dietary fat in cytoplasmic lipid droplets. Lipid droplets can be subsequently mobilized for the production of chylomicrons. The mechanisms that regulate this process are poorly understood. We report here that the milk protein Mfge8 regulates hydrolysis of cytoplasmic lipid droplets in enterocytes after interacting with the αvβ3 and αvβ5 integrins. Mice deficient in Mfge8 or the αvβ3 and αvβ5 integrins accumulate excess cytoplasmic lipid droplets after a fat challenge. Mechanistically, interruption of the Mfge8-integrin axis leads to impaired enterocyte intracellular triglyceride hydrolase activity in vitro and in vivo. Furthermore, Mfge8 increases triglyceride hydrolase activity through a PI3 kinase/mTORC2-dependent signaling pathway. These data identify a key role for Mfge8 and the αvβ3 and αvβ5 integrins in regulating enterocyte lipid processing.
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Affiliation(s)
- Amin Khalifeh-Soltani
- Department of Medicine.,Cardiovascular Research Institute.,Lung Biology Center, University of California, San Francisco, San Francisco, California, USA
| | - Deepti Gupta
- Department of Medicine.,Cardiovascular Research Institute.,Lung Biology Center, University of California, San Francisco, San Francisco, California, USA
| | - Arnold Ha
- Department of Medicine.,Cardiovascular Research Institute
| | - Jahangir Iqbal
- Departments of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, New York, USA
| | - Mahmood Hussain
- Departments of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, New York, USA
| | - Michael J Podolsky
- Department of Medicine.,Cardiovascular Research Institute.,Lung Biology Center, University of California, San Francisco, San Francisco, California, USA
| | - Kamran Atabai
- Department of Medicine.,Cardiovascular Research Institute.,Lung Biology Center, University of California, San Francisco, San Francisco, California, USA
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73
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Namgaladze D, Brüne B. Macrophage fatty acid oxidation and its roles in macrophage polarization and fatty acid-induced inflammation. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1796-1807. [PMID: 27614008 DOI: 10.1016/j.bbalip.2016.09.002] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 08/26/2016] [Accepted: 09/02/2016] [Indexed: 12/14/2022]
Abstract
Recent research considerably changed our knowledge how cellular metabolism affects the immune system. We appreciate that metabolism not only provides energy to immune cells, but also actively influences diverse immune cell phenotypes. Fatty acid metabolism, particularly mitochondrial fatty acid oxidation (FAO) emerges as an important regulator of innate and adaptive immunity. Catabolism of fatty acids also modulates the progression of disease, such as the development of obesity-driven insulin resistance and type II diabetes. Here, we summarize (i) recent developments in research how FAO modulates inflammatory signatures in macrophages in response to saturated fatty acids, and (ii) the role of FAO in regulating anti-inflammatory macrophage polarization. In addition, we define the contribution of AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptors (PPARs), in controlling macrophage biology towards fatty acid metabolism and inflammation.
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Affiliation(s)
- Dmitry Namgaladze
- Goethe-University Frankfurt, Faculty of Medicine, Institute of Biochemistry I, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
| | - Bernhard Brüne
- Goethe-University Frankfurt, Faculty of Medicine, Institute of Biochemistry I, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
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74
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Lord CC, Ferguson D, Thomas G, Brown AL, Schugar RC, Burrows A, Gromovsky AD, Betters J, Neumann C, Sacks J, Marshall S, Watts R, Schweiger M, Lee RG, Crooke RM, Graham MJ, Lathia JD, Sakaguchi TF, Lehner R, Haemmerle G, Zechner R, Brown JM. Regulation of Hepatic Triacylglycerol Metabolism by CGI-58 Does Not Require ATGL Co-activation. Cell Rep 2016; 16:939-949. [PMID: 27396333 DOI: 10.1016/j.celrep.2016.06.049] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 04/20/2016] [Accepted: 06/10/2016] [Indexed: 01/23/2023] Open
Abstract
Adipose triglyceride lipase (ATGL) and comparative gene identification 58 (CGI-58) are critical regulators of triacylglycerol (TAG) turnover. CGI-58 is thought to regulate TAG mobilization by stimulating the enzymatic activity of ATGL. However, it is not known whether this coactivation function of CGI-58 occurs in vivo. Moreover, the phenotype of human CGI-58 mutations suggests ATGL-independent functions. Through direct comparison of mice with single or double deficiency of CGI-58 and ATGL, we show here that CGI-58 knockdown causes hepatic steatosis in both the presence and absence of ATGL. CGI-58 also regulates hepatic diacylglycerol (DAG) and inflammation in an ATGL-independent manner. Interestingly, ATGL deficiency, but not CGI-58 deficiency, results in suppression of the hepatic and adipose de novo lipogenic program. Collectively, these findings show that CGI-58 regulates hepatic neutral lipid storage and inflammation in the genetic absence of ATGL, demonstrating that mechanisms driving TAG lipolysis in hepatocytes differ significantly from those in adipocytes.
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Affiliation(s)
- Caleb C Lord
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1040, USA; Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9077, USA
| | - Daniel Ferguson
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1040, USA; Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Gwynneth Thomas
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1040, USA
| | - Amanda L Brown
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1040, USA; Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Rebecca C Schugar
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Amy Burrows
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Anthony D Gromovsky
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Jenna Betters
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1040, USA
| | - Chase Neumann
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Jessica Sacks
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Stephanie Marshall
- Section on Lipid Sciences, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1040, USA; Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Russell Watts
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Martina Schweiger
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Richard G Lee
- Cardiovascular Group, Antisense Drug Discovery, Ionis Pharmaceuticals, Inc., Carlsbad, CA 92010, USA
| | - Rosanne M Crooke
- Cardiovascular Group, Antisense Drug Discovery, Ionis Pharmaceuticals, Inc., Carlsbad, CA 92010, USA
| | - Mark J Graham
- Cardiovascular Group, Antisense Drug Discovery, Ionis Pharmaceuticals, Inc., Carlsbad, CA 92010, USA
| | - Justin D Lathia
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Takuya F Sakaguchi
- Department of Stem Cell Biology and Regenerative Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Richard Lehner
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
| | - J Mark Brown
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, OH 44195, USA.
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75
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AMPK Phosphorylates Desnutrin/ATGL and Hormone-Sensitive Lipase To Regulate Lipolysis and Fatty Acid Oxidation within Adipose Tissue. Mol Cell Biol 2016; 36:1961-76. [PMID: 27185873 DOI: 10.1128/mcb.00244-16] [Citation(s) in RCA: 192] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 05/06/2016] [Indexed: 01/10/2023] Open
Abstract
The role of AMP-activated protein kinase (AMPK) in promoting fatty acid (FA) oxidation in various tissues, such as liver and muscle, has been well understood. However, the role of AMPK in lipolysis and FA metabolism in adipose tissue has been controversial. To investigate the role of AMPK in the regulation of adipose lipolysis in vivo, we generated mice with adipose-tissue-specific knockout of both the α1 and α2 catalytic subunits of AMPK (AMPK-ASKO mice) by using aP2-Cre and adiponectin-Cre. Both models of AMPK-ASKO ablation show no changes in desnutrin/ATGL levels but have defective phosphorylation of desnutrin/ATGL at S406 to decrease its triacylglycerol (TAG) hydrolase activity, lowering basal lipolysis in adipose tissue. These mice also show defective phosphorylation of hormone-sensitive lipase (HSL) at S565, with higher phosphorylation at protein kinase A sites S563 and S660, increasing its hydrolase activity and isoproterenol-stimulated lipolysis. With higher overall adipose lipolysis, both models of AMPK-ASKO mice are lean, having smaller adipocytes with lower TAG and higher intracellular free-FA levels. Moreover, FAs from higher lipolysis activate peroxisome proliferator-activated receptor delta to induce FA oxidative genes and increase FA oxidation and energy expenditure. Overall, for the first time, we provide in vivo evidence of the role of AMPK in the phosphorylation and regulation of desnutrin/ATGL and HSL and thus adipose lipolysis.
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76
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Grijalva A, Xu X, Ferrante AW. Autophagy Is Dispensable for Macrophage-Mediated Lipid Homeostasis in Adipose Tissue. Diabetes 2016; 65:967-80. [PMID: 26868294 PMCID: PMC4806658 DOI: 10.2337/db15-1219] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 01/15/2016] [Indexed: 12/20/2022]
Abstract
Adipose tissue (AT) macrophages (ATMs) contribute to obesity-induced inflammation and metabolic dysfunction, but also play critical roles in maintaining tissue homeostasis. ATMs catabolize lipid in a lysosomal-dependent manner required for the maintenance of AT; deficiency in lysosomal acid lipase (Lipa), the enzyme required for lysosome lipid catabolism, leads to AT atrophy and severe hepatic steatosis, phenotypes rescued by macrophage-specific expression of Lipa Autophagy delivers cellular products, including lipid droplets, to lysosomes. Given that obesity increases autophagy in AT and contributes to lipid catabolism in other cells, it was proposed that autophagy delivers lipid to lysosomes in ATMs and is required for AT homeostasis. We found that obesity does increase autophagy in ATMs. However, genetic or pharmacological inhibition of autophagy does not alter the lipid balance of ATMs in vitro or in vivo. In contrast to the deficiency of lysosomal lipid hydrolysis, the ablation of autophagy in macrophages does not lead to AT atrophy or alter metabolic phenotypes in lean or obese animals. Although the lysosomal catabolism of lipid is necessary for normal ATM function and AT homeostasis, delivery of lipid to lysosomes is not autophagy dependent and strongly suggests the existence of another lipid delivery pathway critical to lysosome triglyceride hydrolysis in ATMs.
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Affiliation(s)
- Ambar Grijalva
- Department of Medicine, The Naomi Berrie Diabetes Center, Columbia University, New York, NY
| | - Xiaoyuan Xu
- Department of Medicine, The Naomi Berrie Diabetes Center, Columbia University, New York, NY
| | - Anthony W Ferrante
- Department of Medicine, The Naomi Berrie Diabetes Center, Columbia University, New York, NY
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77
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Oishi Y, Manabe I. Integrated regulation of the cellular metabolism and function of immune cells in adipose tissue. Clin Exp Pharmacol Physiol 2016; 43:294-303. [DOI: 10.1111/1440-1681.12539] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 12/28/2015] [Accepted: 12/29/2015] [Indexed: 01/01/2023]
Affiliation(s)
- Yumiko Oishi
- Department of Cellular and Molecular Medicine; Medical Research Institute; Tokyo Medical and Dental University; Tokyo Japan
| | - Ichiro Manabe
- Department of Aging Research; Graduate School of Medicine; Chiba University; Chiba Japan
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78
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de Macedo CS, Anderson DM, Pascarelli BM, Spraggins JM, Sarno EN, Schey KL, Pessolani MCV. MALDI imaging reveals lipid changes in the skin of leprosy patients before and after multidrug therapy (MDT). JOURNAL OF MASS SPECTROMETRY : JMS 2015; 50:1374-85. [PMID: 26634971 DOI: 10.1002/jms.3708] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/17/2015] [Indexed: 05/28/2023]
Abstract
Leprosy still represents a health problem in several countries. Affecting skin and peripheral nerves, it may lead to permanent disabilities. Disturbances on skin lipid metabolism in leprosy were already observed; however, the localization and distribution of lipids could not be accessed. The role of lipids on infectious disease has been fully addressed only recently, as they directly influence immune response. Matrix-assisted laser desorption/ionization imaging mass spectrometry provides a powerful tool to localize and identify lipids in tissues. The aim of this work was to study and compare the changes in lipid distribution of skin biopsies taken from leprosy patients before and after multidrug therapy (MDT). Different species of phosphatidic acid, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, sphingomyelin and phosphatidylcholine were detected. Differences in skin lipid signal intensities, as well as in their localization, were observed before and after MDT in every patient. In general, lipid distribution in the skin after MDT had a pattern similar to control skin samples, where most of the lipids were located in the upper part of the dermis and epidermis. This study opens paths to a better understanding of lipid functions in leprosy pathogenesis and immune response.
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Affiliation(s)
- Cristiana S de Macedo
- Center for Technological Development in Health (CDTS), Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, RJ, Brazil
- Oswaldo Cruz Institute (IOC) - Cellular Microbiology Laboratory, Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, RJ, Brazil
| | - David M Anderson
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN, USA
| | - Bernardo M Pascarelli
- Oswaldo Cruz Institute (IOC) - Leprosy Laboratory, Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, RJ, Brazil
| | - Jeffrey M Spraggins
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN, USA
| | - Euzenir N Sarno
- Oswaldo Cruz Institute (IOC) - Leprosy Laboratory, Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, RJ, Brazil
| | - Kevin L Schey
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN, USA
| | - Maria Cristina V Pessolani
- Oswaldo Cruz Institute (IOC) - Cellular Microbiology Laboratory, Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, RJ, Brazil
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Schoiswohl G, Stefanovic-Racic M, Menke MN, Wills RC, Surlow BA, Basantani MK, Sitnick MT, Cai L, Yazbeck CF, Stolz DB, Pulinilkunnil T, O'Doherty RM, Kershaw EE. Impact of Reduced ATGL-Mediated Adipocyte Lipolysis on Obesity-Associated Insulin Resistance and Inflammation in Male Mice. Endocrinology 2015; 156. [PMID: 26196542 PMCID: PMC4588821 DOI: 10.1210/en.2015-1322] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Emerging evidence suggests that impaired regulation of adipocyte lipolysis contributes to the proinflammatory immune cell infiltration of metabolic tissues in obesity, a process that is proposed to contribute to the development and exacerbation of insulin resistance. To test this hypothesis in vivo, we generated mice with adipocyte-specific deletion of adipose triglyceride lipase (ATGL), the rate-limiting enzyme catalyzing triacylglycerol hydrolysis. In contrast to previous models, adiponectin-driven Cre expression was used for targeted ATGL deletion. The resulting adipocyte-specific ATGL knockout (AAKO) mice were then characterized for metabolic and immune phenotypes. Lean and diet-induced obese AAKO mice had reduced adipocyte lipolysis, serum lipids, systemic lipid oxidation, and expression of peroxisome proliferator-activated receptor alpha target genes in adipose tissue (AT) and liver. These changes did not increase overall body weight or fat mass in AAKO mice by 24 weeks of age, in part due to reduced expression of genes involved in lipid uptake, synthesis, and adipogenesis. Systemic glucose and insulin tolerance were improved in AAKO mice, primarily due to enhanced hepatic insulin signaling, which was accompanied by marked reduction in diet-induced hepatic steatosis as well as hepatic immune cell infiltration and activation. In contrast, although adipocyte ATGL deletion reduced AT immune cell infiltration in response to an acute lipolytic stimulus, it was not sufficient to ameliorate, and may even exacerbate, chronic inflammatory changes that occur in AT in response to diet-induced obesity.
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Affiliation(s)
- Gabriele Schoiswohl
- Division of Endocrinology and Metabolism (G.S., M.S.-R., R.C.W., B.A.S., M.K.B., M.T.S., L.C., C.F.Y., R.M.O., E.E.K.), Department of Medicine, and Department of Cell Biology (D.B.S.), University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Obstetrics, Gynecology, and Reproductive Sciences (M.N.M.), Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania 15213; and Department of Biochemistry and Molecular Biology (T.P.), Dalhousie Medicine New Brunswick, Dalhousie University, St John, Canada NB E2L 4L5
| | - Maja Stefanovic-Racic
- Division of Endocrinology and Metabolism (G.S., M.S.-R., R.C.W., B.A.S., M.K.B., M.T.S., L.C., C.F.Y., R.M.O., E.E.K.), Department of Medicine, and Department of Cell Biology (D.B.S.), University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Obstetrics, Gynecology, and Reproductive Sciences (M.N.M.), Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania 15213; and Department of Biochemistry and Molecular Biology (T.P.), Dalhousie Medicine New Brunswick, Dalhousie University, St John, Canada NB E2L 4L5
| | - Marie N Menke
- Division of Endocrinology and Metabolism (G.S., M.S.-R., R.C.W., B.A.S., M.K.B., M.T.S., L.C., C.F.Y., R.M.O., E.E.K.), Department of Medicine, and Department of Cell Biology (D.B.S.), University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Obstetrics, Gynecology, and Reproductive Sciences (M.N.M.), Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania 15213; and Department of Biochemistry and Molecular Biology (T.P.), Dalhousie Medicine New Brunswick, Dalhousie University, St John, Canada NB E2L 4L5
| | - Rachel C Wills
- Division of Endocrinology and Metabolism (G.S., M.S.-R., R.C.W., B.A.S., M.K.B., M.T.S., L.C., C.F.Y., R.M.O., E.E.K.), Department of Medicine, and Department of Cell Biology (D.B.S.), University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Obstetrics, Gynecology, and Reproductive Sciences (M.N.M.), Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania 15213; and Department of Biochemistry and Molecular Biology (T.P.), Dalhousie Medicine New Brunswick, Dalhousie University, St John, Canada NB E2L 4L5
| | - Beth A Surlow
- Division of Endocrinology and Metabolism (G.S., M.S.-R., R.C.W., B.A.S., M.K.B., M.T.S., L.C., C.F.Y., R.M.O., E.E.K.), Department of Medicine, and Department of Cell Biology (D.B.S.), University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Obstetrics, Gynecology, and Reproductive Sciences (M.N.M.), Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania 15213; and Department of Biochemistry and Molecular Biology (T.P.), Dalhousie Medicine New Brunswick, Dalhousie University, St John, Canada NB E2L 4L5
| | - Mahesh K Basantani
- Division of Endocrinology and Metabolism (G.S., M.S.-R., R.C.W., B.A.S., M.K.B., M.T.S., L.C., C.F.Y., R.M.O., E.E.K.), Department of Medicine, and Department of Cell Biology (D.B.S.), University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Obstetrics, Gynecology, and Reproductive Sciences (M.N.M.), Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania 15213; and Department of Biochemistry and Molecular Biology (T.P.), Dalhousie Medicine New Brunswick, Dalhousie University, St John, Canada NB E2L 4L5
| | - Mitch T Sitnick
- Division of Endocrinology and Metabolism (G.S., M.S.-R., R.C.W., B.A.S., M.K.B., M.T.S., L.C., C.F.Y., R.M.O., E.E.K.), Department of Medicine, and Department of Cell Biology (D.B.S.), University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Obstetrics, Gynecology, and Reproductive Sciences (M.N.M.), Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania 15213; and Department of Biochemistry and Molecular Biology (T.P.), Dalhousie Medicine New Brunswick, Dalhousie University, St John, Canada NB E2L 4L5
| | - Lingzhi Cai
- Division of Endocrinology and Metabolism (G.S., M.S.-R., R.C.W., B.A.S., M.K.B., M.T.S., L.C., C.F.Y., R.M.O., E.E.K.), Department of Medicine, and Department of Cell Biology (D.B.S.), University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Obstetrics, Gynecology, and Reproductive Sciences (M.N.M.), Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania 15213; and Department of Biochemistry and Molecular Biology (T.P.), Dalhousie Medicine New Brunswick, Dalhousie University, St John, Canada NB E2L 4L5
| | - Cynthia F Yazbeck
- Division of Endocrinology and Metabolism (G.S., M.S.-R., R.C.W., B.A.S., M.K.B., M.T.S., L.C., C.F.Y., R.M.O., E.E.K.), Department of Medicine, and Department of Cell Biology (D.B.S.), University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Obstetrics, Gynecology, and Reproductive Sciences (M.N.M.), Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania 15213; and Department of Biochemistry and Molecular Biology (T.P.), Dalhousie Medicine New Brunswick, Dalhousie University, St John, Canada NB E2L 4L5
| | - Donna B Stolz
- Division of Endocrinology and Metabolism (G.S., M.S.-R., R.C.W., B.A.S., M.K.B., M.T.S., L.C., C.F.Y., R.M.O., E.E.K.), Department of Medicine, and Department of Cell Biology (D.B.S.), University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Obstetrics, Gynecology, and Reproductive Sciences (M.N.M.), Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania 15213; and Department of Biochemistry and Molecular Biology (T.P.), Dalhousie Medicine New Brunswick, Dalhousie University, St John, Canada NB E2L 4L5
| | - Thomas Pulinilkunnil
- Division of Endocrinology and Metabolism (G.S., M.S.-R., R.C.W., B.A.S., M.K.B., M.T.S., L.C., C.F.Y., R.M.O., E.E.K.), Department of Medicine, and Department of Cell Biology (D.B.S.), University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Obstetrics, Gynecology, and Reproductive Sciences (M.N.M.), Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania 15213; and Department of Biochemistry and Molecular Biology (T.P.), Dalhousie Medicine New Brunswick, Dalhousie University, St John, Canada NB E2L 4L5
| | - Robert M O'Doherty
- Division of Endocrinology and Metabolism (G.S., M.S.-R., R.C.W., B.A.S., M.K.B., M.T.S., L.C., C.F.Y., R.M.O., E.E.K.), Department of Medicine, and Department of Cell Biology (D.B.S.), University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Obstetrics, Gynecology, and Reproductive Sciences (M.N.M.), Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania 15213; and Department of Biochemistry and Molecular Biology (T.P.), Dalhousie Medicine New Brunswick, Dalhousie University, St John, Canada NB E2L 4L5
| | - Erin E Kershaw
- Division of Endocrinology and Metabolism (G.S., M.S.-R., R.C.W., B.A.S., M.K.B., M.T.S., L.C., C.F.Y., R.M.O., E.E.K.), Department of Medicine, and Department of Cell Biology (D.B.S.), University of Pittsburgh, Pittsburgh, Pennsylvania 15261; Department of Obstetrics, Gynecology, and Reproductive Sciences (M.N.M.), Magee-Womens Hospital, University of Pittsburgh, Pittsburgh, Pennsylvania 15213; and Department of Biochemistry and Molecular Biology (T.P.), Dalhousie Medicine New Brunswick, Dalhousie University, St John, Canada NB E2L 4L5
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80
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Host cell phosphatidylcholine is a key mediator of malaria parasite survival during liver stage infection. Cell Host Microbe 2015; 16:778-86. [PMID: 25498345 PMCID: PMC4271766 DOI: 10.1016/j.chom.2014.11.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/29/2014] [Accepted: 11/04/2014] [Indexed: 01/22/2023]
Abstract
During invasion, Plasmodium, the causative agent of malaria, wraps itself in a parasitophorous vacuole membrane (PVM), which constitutes a critical interface between the parasite and its host cell. Within hepatocytes, each Plasmodium sporozoite generates thousands of new parasites, creating high demand for lipids to support this replication and enlarge the PVM. Here, a global analysis of the total lipid repertoire of Plasmodium-infected hepatocytes reveals an enrichment of neutral lipids and the major membrane phospholipid, phosphatidylcholine (PC). While infection is unaffected in mice deficient in key enzymes involved in neutral lipid synthesis and lipolysis, ablation of rate-limiting enzymes in hepatic PC biosynthetic pathways significantly decreases parasite numbers. Host PC is taken up by both P. berghei and P. falciparum and is necessary for correct localization of parasite proteins to the PVM, which is essential for parasite survival. Thus, Plasmodium relies on the abundance of these lipids within hepatocytes to support infection.
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81
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Goeritzer M, Vujic N, Schlager S, Chandak PG, Korbelius M, Gottschalk B, Leopold C, Obrowsky S, Rainer S, Doddapattar P, Aflaki E, Wegscheider M, Sachdev V, Graier WF, Kolb D, Radovic B, Kratky D. Active autophagy but not lipophagy in macrophages with defective lipolysis. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:1304-1316. [PMID: 26143381 PMCID: PMC4562370 DOI: 10.1016/j.bbalip.2015.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 05/29/2015] [Accepted: 06/20/2015] [Indexed: 11/30/2022]
Abstract
During autophagy, autophagosomes fuse with lysosomes to degrade damaged organelles and misfolded proteins. Breakdown products are released into the cytosol and contribute to energy and metabolic building block supply, especially during starvation. Lipophagy has been defined as the autophagy-mediated degradation of lipid droplets (LDs) by lysosomal acid lipase. Adipose triglyceride lipase (ATGL) is the major enzyme catalyzing the initial step of lipolysis by hydrolyzing triglycerides (TGs) in cytosolic LDs. Consequently, most organs and cells, including macrophages, lacking ATGL accumulate TGs, resulting in reduced intracellular free fatty acid concentrations. Macrophages deficient in hormone-sensitive lipase (H0) lack TG accumulation albeit reduced in vitro TG hydrolase activity. We hypothesized that autophagy is activated in lipase-deficient macrophages to counteract their energy deficit. We therefore generated mice lacking both ATGL and HSL (A0H0). Macrophages from A0H0 mice showed 73% reduced neutral TG hydrolase activity, resulting in TG-rich LD accumulation. Increased expression of cathepsin B, accumulation of LC3-II, reduced expression of p62 and increased DQ-BSA dequenching suggest intact autophagy and functional lysosomes in A0H0 macrophages. Markedly decreased acid TG hydrolase activity and lipid flux independent of bafilomycin A1 treatment, however, argue against effective lysosomal degradation of LDs in A0H0 macrophages. We conclude that autophagy of proteins and cell organelles but not of LDs is active as a compensatory mechanism to circumvent and balance the reduced availability of energy substrates in A0H0 macrophages.
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Affiliation(s)
- Madeleine Goeritzer
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Nemanja Vujic
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Stefanie Schlager
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Prakash G Chandak
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Melanie Korbelius
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Benjamin Gottschalk
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Christina Leopold
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Sascha Obrowsky
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Silvia Rainer
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Prakash Doddapattar
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Elma Aflaki
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Martin Wegscheider
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Vinay Sachdev
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Wolfgang F Graier
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Dagmar Kolb
- Center for Medical Research/Institute of Cell Biology, Histology and Embryology, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Branislav Radovic
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Dagmar Kratky
- Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
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82
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Taschler U, Schreiber R, Chitraju C, Grabner GF, Romauch M, Wolinski H, Haemmerle G, Breinbauer R, Zechner R, Lass A, Zimmermann R. Adipose triglyceride lipase is involved in the mobilization of triglyceride and retinoid stores of hepatic stellate cells. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:937-45. [PMID: 25732851 PMCID: PMC4408194 DOI: 10.1016/j.bbalip.2015.02.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 02/05/2015] [Accepted: 02/22/2015] [Indexed: 01/04/2023]
Abstract
Hepatic stellate cells (HSCs) store triglycerides (TGs) and retinyl ester (RE) in cytosolic lipid droplets. RE stores are degraded following retinoid starvation or in response to pathogenic stimuli resulting in HSC activation. At present, the major enzymes catalyzing lipid degradation in HSCs are unknown. In this study, we investigated whether adipose triglyceride lipase (ATGL) is involved in RE catabolism of HSCs. Additionally, we compared the effects of ATGL deficiency and hormone-sensitive lipase (HSL) deficiency, a known RE hydrolase (REH), on RE stores in liver and adipose tissue. We show that ATGL degrades RE even in the presence of TGs, implicating that these substrates compete for ATGL binding. REH activity was stimulated and inhibited by comparative gene identification-58 and G0/G1 switch gene-2, respectively, the physiological regulators of ATGL activity. In cultured primary murine HSCs, pharmacological inhibition of ATGL, but not HSL, increased RE accumulation. In mice globally lacking ATGL or HSL, RE contents in white adipose tissue were decreased or increased, respectively, while plasma retinol and liver RE levels remained unchanged. In conclusion, our study shows that ATGL acts as REH in HSCs promoting the degradation of RE stores in addition to its established function as TG lipase. HSL is the predominant REH in adipocytes but does not affect lipid mobilization in HSCs. ATGL possesses retinyl ester and triacylglycerol hydrolase activity. The lack of ATGL activity causes increased triacylglycerol and retinyl ester storage in hepatic stellate cells. ATGL acts as retinyl ester and triacylglycerol lipase in hepatic stellate cells.
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Affiliation(s)
- Ulrike Taschler
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | | | - Gernot F Grabner
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | - Matthias Romauch
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | - Rolf Breinbauer
- Institute of Organic Chemistry, Graz University of Technology, Graz 8010, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria
| | - Achim Lass
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria.
| | - Robert Zimmermann
- Institute of Molecular Biosciences, University of Graz, Graz 8010, Austria.
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83
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Vorkas PA, Shalhoub J, Isaac G, Want EJ, Nicholson JK, Holmes E, Davies AH. Metabolic Phenotyping of Atherosclerotic Plaques Reveals Latent Associations between Free Cholesterol and Ceramide Metabolism in Atherogenesis. J Proteome Res 2015; 14:1389-99. [DOI: 10.1021/pr5009898] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Panagiotis A. Vorkas
- Biomolecular
Medicine, Division of Computational and Systems Medicine, Department
of Surgery and Cancer, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
| | - Joseph Shalhoub
- Academic
Section of Vascular Surgery, Division of Surgery, Department of Surgery
and Cancer, Faculty of Medicine, Imperial College London, London W6 8RF, United Kingdom
| | - Giorgis Isaac
- Pharmaceutical
Discovery and Life Sciences, Waters Corporations, Milford, Massachusetts 01757, United States
| | - Elizabeth J. Want
- Biomolecular
Medicine, Division of Computational and Systems Medicine, Department
of Surgery and Cancer, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
| | - Jeremy K. Nicholson
- Biomolecular
Medicine, Division of Computational and Systems Medicine, Department
of Surgery and Cancer, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
| | - Elaine Holmes
- Biomolecular
Medicine, Division of Computational and Systems Medicine, Department
of Surgery and Cancer, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
| | - Alun H. Davies
- Academic
Section of Vascular Surgery, Division of Surgery, Department of Surgery
and Cancer, Faculty of Medicine, Imperial College London, London W6 8RF, United Kingdom
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84
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Fatty acid signaling: the new function of intracellular lipases. Int J Mol Sci 2015; 16:3831-55. [PMID: 25674855 PMCID: PMC4346929 DOI: 10.3390/ijms16023831] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 11/19/2014] [Accepted: 01/21/2015] [Indexed: 12/21/2022] Open
Abstract
Until recently, intracellular triacylglycerols (TAG) stored in the form of cytoplasmic lipid droplets have been considered to be only passive “energy conserves”. Nevertheless, degradation of TAG gives rise to a pleiotropic spectrum of bioactive intermediates, which may function as potent co-factors of transcription factors or enzymes and contribute to the regulation of numerous cellular processes. From this point of view, the process of lipolysis not only provides energy-rich equivalents but also acquires a new regulatory function. In this review, we will concentrate on the role that fatty acids liberated from intracellular TAG stores play as signaling molecules. The first part provides an overview of the transcription factors, which are regulated by fatty acids derived from intracellular stores. The second part is devoted to the role of fatty acid signaling in different organs/tissues. The specific contribution of free fatty acids released by particular lipases, hormone-sensitive lipase, adipose triacylglycerol lipase and lysosomal lipase will also be discussed.
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85
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Schreiber R, Zechner R. Lipolysis meets inflammation: arachidonic acid mobilization from fat. J Lipid Res 2014; 55:2447-9. [PMID: 25332433 DOI: 10.1194/jlr.c055673] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Renate Schreiber
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Austria
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86
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Goeritzer M, Schlager S, Radovic B, Madreiter CT, Rainer S, Thomas G, Lord CC, Sacks J, Brown AL, Vujic N, Obrowsky S, Sachdev V, Kolb D, Chandak PG, Graier WF, Sattler W, Brown JM, Kratky D. Deletion of CGI-58 or adipose triglyceride lipase differently affects macrophage function and atherosclerosis. J Lipid Res 2014; 55:2562-75. [PMID: 25316883 PMCID: PMC4242449 DOI: 10.1194/jlr.m052613] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Cellular TG stores are efficiently hydrolyzed by adipose TG lipase (ATGL). Its coactivator comparative gene identification-58 (CGI-58) strongly increases ATGL-mediated TG catabolism in cell culture experiments. To investigate the consequences of CGI-58 deficiency in murine macrophages, we generated mice with a targeted deletion of CGI-58 in myeloid cells (macCGI-58(-/-) mice). CGI-58(-/-) macrophages accumulate intracellular TG-rich lipid droplets and have decreased phagocytic capacity, comparable to ATGL(-/-) macrophages. In contrast to ATGL(-/-) macrophages, however, CGI-58(-/-) macrophages have intact mitochondria and show no indications of mitochondrial apoptosis and endoplasmic reticulum stress, suggesting that TG accumulation per se lacks a significant role in processes leading to mitochondrial dysfunction. Another notable difference is the fact that CGI-58(-/-) macrophages adopt an M1-like phenotype in vitro. Finally, we investigated atherosclerosis susceptibility in macCGI-58/ApoE-double KO (DKO) animals. In response to high-fat/high-cholesterol diet feeding, DKO animals showed comparable plaque formation as observed in ApoE(-/-) mice. In agreement, antisense oligonucleotide-mediated knockdown of CGI-58 in LDL receptor(-/-) mice did not alter atherosclerosis burden in the aortic root. These results suggest that macrophage function and atherosclerosis susceptibility differ fundamentally in these two animal models with disturbed TG catabolism, showing a more severe phenotype by ATGL deficiency.
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Affiliation(s)
- Madeleine Goeritzer
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Stefanie Schlager
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Branislav Radovic
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Corina T Madreiter
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Silvia Rainer
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Gwynneth Thomas
- Department of Pathology, Section on Lipid Sciences, Wake Forest University School of Medicine, Winston-Salem, NC
| | - Caleb C Lord
- Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, TX
| | - Jessica Sacks
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH
| | - Amanda L Brown
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH
| | - Nemanja Vujic
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Sascha Obrowsky
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Vinay Sachdev
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Dagmar Kolb
- Center for Medical Research/Institute of Cell Biology, Histology, and Embryology, Medical University of Graz, Graz, Austria
| | - Prakash G Chandak
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Wolfgang F Graier
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Wolfgang Sattler
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - J Mark Brown
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH
| | - Dagmar Kratky
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
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87
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Meana C, Peña L, Lordén G, Esquinas E, Guijas C, Valdearcos M, Balsinde J, Balboa MA. Lipin-1 integrates lipid synthesis with proinflammatory responses during TLR activation in macrophages. THE JOURNAL OF IMMUNOLOGY 2014; 193:4614-22. [PMID: 25252959 DOI: 10.4049/jimmunol.1400238] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Lipin-1 is a Mg(2+)-dependent phosphatidic acid phosphatase involved in the de novo synthesis of phospholipids and triglycerides. Using macrophages from lipin-1-deficient animals and human macrophages deficient in the enzyme, we show in this work that this phosphatase acts as a proinflammatory mediator during TLR signaling and during the development of in vivo inflammatory processes. After TLR4 stimulation lipin-1-deficient macrophages showed a decreased production of diacylglycerol and activation of MAPKs and AP-1. Consequently, the generation of proinflammatory cytokines like IL-6, IL-12, IL-23, or enzymes like inducible NO synthase and cyclooxygenase 2, was reduced. In addition, animals lacking lipin-1 had a faster recovery from endotoxin administration concomitant with a reduced production of harmful molecules in spleen and liver. These findings demonstrate an unanticipated role for lipin-1 as a mediator of macrophage proinflammatory activation and support a critical link between lipid biosynthesis and systemic inflammatory responses.
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Affiliation(s)
- Clara Meana
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, 47003 Valladolid, Spain; and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, 28029 Madrid, Spain
| | - Lucía Peña
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, 47003 Valladolid, Spain; and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, 28029 Madrid, Spain
| | - Gema Lordén
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, 47003 Valladolid, Spain; and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, 28029 Madrid, Spain
| | - Esperanza Esquinas
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, 47003 Valladolid, Spain; and
| | - Carlos Guijas
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, 47003 Valladolid, Spain; and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, 28029 Madrid, Spain
| | - Martín Valdearcos
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, 47003 Valladolid, Spain; and
| | - Jesús Balsinde
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, 47003 Valladolid, Spain; and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, 28029 Madrid, Spain
| | - María A Balboa
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas, Universidad de Valladolid, 47003 Valladolid, Spain; and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, 28029 Madrid, Spain
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88
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Dichlberger A, Schlager S, Maaninka K, Schneider WJ, Kovanen PT. Adipose triglyceride lipase regulates eicosanoid production in activated human mast cells. J Lipid Res 2014; 55:2471-8. [PMID: 25114172 DOI: 10.1194/jlr.m048553] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human mast cells (MCs) contain TG-rich cytoplasmic lipid droplets (LDs) with high arachidonic acid (AA) content. Here, we investigated the functional role of adipose TG lipase (ATGL) in TG hydrolysis and the ensuing release of AA as substrate for eicosanoid generation by activated human primary MCs in culture. Silencing of ATGL in MCs by siRNAs induced the accumulation of neutral lipids in LDs. IgE-dependent activation of MCs triggered the secretion of the two major eicosanoids, prostaglandin D2 (PGD2) and leukotriene C4 (LTC4). The immediate release of PGD2 from the activated MCs was solely dependent on cyclooxygenase (COX) 1, while during the delayed phase of lipid mediator production, the inducible COX-2 also contributed to its release. Importantly, when ATGL-silenced MCs were activated, the secretion of both PGD2 and LTC4 was significantly reduced. Interestingly, the inhibitory effect on the release of LTC4 was even more pronounced in ATGL-silenced MCs than in cytosolic phospholipase A2-silenced MCs. These data show that ATGL hydrolyzes AA-containing TGs present in human MC LDs and define ATGL as a novel regulator of the substrate availability of AA for eicosanoid generation upon MC activation.
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Affiliation(s)
| | | | | | - Wolfgang J Schneider
- Department of Medical Biochemistry, Medical University Vienna, Max F. Perutz Laboratories, 1030 Vienna, Austria
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89
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Lu M, Kho T, Munford RS. Prolonged triglyceride storage in macrophages: pHo trumps pO2 and TLR4. THE JOURNAL OF IMMUNOLOGY 2014; 193:1392-7. [PMID: 24973452 DOI: 10.4049/jimmunol.1400886] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Lipid-laden macrophages contribute to pathologies as diverse as atherosclerosis and tuberculosis. Three common stimuli are known to promote macrophage lipid storage: low tissue oxygen tension (pO2), low extracellular pH (pHo), and exposure to agonists such as bacterial LPS. Noting that cells responding to low pO2 or agonistic bacterial molecules often decrease pHo by secreting lactic and other carboxylic acids, we studied how pHo influences the stimulation of triacylglycerol (TAG) storage by low pO2 and LPS. We found that TAG retention after incubation for 48-72 h was inversely related to pHo when primary macrophages were cultured in 21% oxygen, 4% oxygen, or with LPS at either oxygen concentration. Maintaining pHo at ~7.4 was sufficient to prevent the increase in prolonged TAG storage induced by either low pO2 or LPS. The strong influence of pHo on TAG retention may explain why lipid-laden macrophages are found in some tissue environments and not in others. It is also possible that other long-term cellular changes currently attributed to low pO2 or bacterial agonists may be promoted, at least in part, by the decrease in pHo that these stimuli induce.
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Affiliation(s)
- Mingfang Lu
- Antibacterial Host Defense Unit, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Terry Kho
- Antibacterial Host Defense Unit, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Robert S Munford
- Antibacterial Host Defense Unit, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
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90
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Zierler KA, Zechner R, Haemmerle G. Comparative gene identification-58/α/β hydrolase domain 5: more than just an adipose triglyceride lipase activator? Curr Opin Lipidol 2014; 25:102-9. [PMID: 24565921 PMCID: PMC4170181 DOI: 10.1097/mol.0000000000000058] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW Comparative gene identification-58 (CGI-58) is a lipid droplet-associated protein that controls intracellular triglyceride levels by its ability to activate adipose triglyceride lipase (ATGL). Additionally, CGI-58 was described to exhibit lysophosphatidic acid acyl transferase (LPAAT) activity. This review focuses on the significance of CGI-58 in energy metabolism in adipose and nonadipose tissue. RECENT FINDINGS Recent studies with transgenic and CGI-58-deficient mouse strains underscored the importance of CGI-58 as a regulator of intracellular energy homeostasis by modulating ATGL-driven triglyceride hydrolysis. In accordance with this function, mice and humans that lack CGI-58 accumulate triglyceride in multiple tissues. Additionally, CGI-58-deficient mice develop an ATGL-independent severe skin barrier defect and die soon after birth. Although the premature death prevented a phenotypical characterization of adult global CGI-58 knockout mice, the characterization of mice with tissue-specific CGI-58 deficiency revealed new insights into its role in neutral lipid and energy metabolism. Concerning the ATGL-independent function of CGI-58, a recently identified LPAAT activity for CGI-58 was shown to be involved in the generation of signaling molecules regulating inflammatory processes and insulin action. SUMMARY Although the function of CGI-58 in the catabolism of cellular triglyceride depots via ATGL is well established, further studies are required to consolidate the function of CGI-58 as LPAAT and to clarify the involvement of CGI-58 in the metabolism of skin lipids.
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Affiliation(s)
- Kathrin A Zierler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
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91
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Kratky D, Obrowsky S, Kolb D, Radovic B. Pleiotropic regulation of mitochondrial function by adipose triglyceride lipase-mediated lipolysis. Biochimie 2014; 96:106-12. [PMID: 23827855 PMCID: PMC3859496 DOI: 10.1016/j.biochi.2013.06.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 06/20/2013] [Indexed: 12/12/2022]
Abstract
Lipolysis is defined as the catabolism of triacylglycerols (TGs) stored in cellular lipid droplets. Recent discoveries of essential lipolytic enzymes and characterization of numerous regulatory proteins and mechanisms have fundamentally changed our perception of lipolysis and its impact on cellular metabolism. Adipose triglyceride lipase (ATGL) is the rate-limiting enzyme for TG catabolism in most cells and tissues. This review focuses on recent advances in understanding the (patho)physiological impact due to defective lipolysis by ATGL deficiency on mitochondrial (dys)function. Depending on the type of cells and tissues investigated, absence of ATGL has pleiotropic roles in mitochondrial function.
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Affiliation(s)
- Dagmar Kratky
- Institute of Molecular Biology and Biochemistry, Center for Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria.
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92
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Abstract
A key function of the skin is to provide a permeability barrier to restrict the movement of water, electrolytes, and other small molecules between the outside environment and the internal milieu. Following disruption of the permeability barrier, there is a rapid restoration of barrier function, and one of the key signals initiating this repair response is a decrease in the concentration of calcium in the outer epidermis. In this issue, Borkowski et al. present evidence showing that activation of Toll receptor 3 by double-stranded RNA may be another pathway for activation of permeability barrier repair. These results provide further evidence for a link between innate immunity and the permeability barrier.
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Affiliation(s)
- Kenneth R Feingold
- Metabolism Section (111F), Department of Veterans Affairs Medical Center, University of California, San Francisco, San Francisco, California 94121, USA.
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93
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Millership S, Ninkina N, Rochford JJ, Buchman VL. γ-synuclein is a novel player in the control of body lipid metabolism. Adipocyte 2013; 2:276-80. [PMID: 24052906 PMCID: PMC3774706 DOI: 10.4161/adip.25162] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 05/21/2013] [Accepted: 05/23/2013] [Indexed: 12/11/2022] Open
Abstract
Synucleins are a family of homologous, predominantly neuronal proteins known for their involvement in synaptic transmission and neurodegeneration. γ-synuclein is predominantly localized in axons and presynaptic terminals of selected populations of peripheral and central neurons but is also highly expressed in human white adipose tissue (WAT) and increased in obesity. We have recently shown that γ-synuclein is nutritionally regulated in murine adipocytes while its loss protects mice from high fat diet (HFD)-induced obesity and associated metabolic complications. This protection was coupled with increased adipocyte lipolysis, lipid oxidation, and energy expenditure in HFD-fed γ-synuclein-null mutant compared with wild-type mice. Cellular studies suggest that relocalization of ATGL to the lipid droplet in γ-synuclein-deficient adipocytes may contribute to increased lipolysis in these cells. Loss of γ-synuclein in adipocytes also attenuates the assembly of SNARE complexes, an important component of lipid droplet fusion machinery, possibly due to reduced chaperoning of SNAP-23 to the assembling SNARE complex by γ-synuclein. Together our data suggests that not only is γ-synuclein a novel regulator of lipid handling in adipocytes but also that the deficiency of this protein has a significant effect on whole body energy expenditure.
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94
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Takahashi M, Yagyu H, Tazoe F, Nagashima S, Ohshiro T, Okada K, Osuga JI, Goldberg IJ, Ishibashi S. Macrophage lipoprotein lipase modulates the development of atherosclerosis but not adiposity. J Lipid Res 2013; 54:1124-34. [PMID: 23378601 DOI: 10.1194/jlr.m035568] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The role of macrophage lipoprotein lipase (LpL) in the development of atherosclerosis and adiposity was examined in macrophage LpL knockout (MLpLKO) mice. MLpLKO mice were generated using cre-loxP gene targeting. Loss of LpL in macrophages did not alter plasma LpL activity or lipoprotein levels. Incubation of apolipoprotein E (ApoE)-deficient β-VLDL with peritoneal macrophages from ApoE knockout mice lacking macrophage LpL (MLpLKO/ApoEKO) led to less cholesteryl ester formation than that found with ApoEKO macrophages. MLpLKO/ApoEKO macrophages had reduced intracellular triglyceride levels, with decreased CD36 and carnitine palmitoyltransferase-1 mRNA levels compared with ApoEKO macrophages, when incubated with VLDL. Although both MLpLKO/ApoEKO and ApoEKO mice developed comparable hypercholesterolemia in response to feeding with a Western-type diet for 12 weeks, atherosclerosis was less in MLpLKO/ApoEKO mice. Epididymal fat mass and gene expression levels associated with inflammation did not differ between the two groups. In conclusion, macrophage LpL plays an important role in the development of atherosclerosis but not adiposity.
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Affiliation(s)
- Manabu Takahashi
- Department of Medicine, Jichi Medical University, Tochigi 329-0498, Japan
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95
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Millership S, Ninkina N, Guschina IA, Norton J, Brambilla R, Oort PJ, Adams SH, Dennis RJ, Voshol PJ, Rochford JJ, Buchman VL. Increased lipolysis and altered lipid homeostasis protect γ-synuclein-null mutant mice from diet-induced obesity. Proc Natl Acad Sci U S A 2012; 109:20943-8. [PMID: 23213245 PMCID: PMC3529034 DOI: 10.1073/pnas.1210022110] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Synucleins are a family of homologous proteins principally known for their involvement in neurodegeneration. γ-Synuclein is highly expressed in human white adipose tissue and increased in obesity. Here we show that γ-synuclein is nutritionally regulated in white adipose tissue whereas its loss partially protects mice from high-fat diet (HFD)-induced obesity and ameliorates some of the associated metabolic complications. Compared with HFD-fed WT mice, HFD-fed γ-synuclein-null mutant mice display increased lipolysis, lipid oxidation, and energy expenditure, and reduced adipocyte hypertrophy. Knockdown of γ-synuclein in adipocytes causes redistribution of the key lipolytic enzyme ATGL to lipid droplets and increases lipolysis. γ-Synuclein-deficient adipocytes also contain fewer SNARE complexes of a type involved in lipid droplet fusion. We hypothesize that γ-synuclein may deliver SNAP-23 to the SNARE complexes under lipogenic conditions. Via these independent but complementary roles, γ-synuclein may coordinately modulate lipid storage by influencing lipolysis and lipid droplet formation. Our data reveal γ-synuclein as a regulator of lipid handling in adipocytes, the function of which is particularly important in conditions of nutrient excess.
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Affiliation(s)
- Steven Millership
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
| | - Natalia Ninkina
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
| | - Irina A. Guschina
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
| | - Jessica Norton
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
| | - Riccardo Brambilla
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
- Division of Neuroscience, Institute of Experimental Neurology, San Raffaele Foundation and University, 20132 Milan, Italy
| | - Pieter J. Oort
- Obesity and Metabolism Research Unit, US Department of Agriculture/Agricultural Research Service Western Human Nutrition Research Center, Davis, CA 95616; and
| | - Sean H. Adams
- Obesity and Metabolism Research Unit, US Department of Agriculture/Agricultural Research Service Western Human Nutrition Research Center, Davis, CA 95616; and
| | - Rowena J. Dennis
- Institute of Metabolic Science, University of Cambridge Metabolic Research Laboratories and National Institute for Health Research Cambridge Biomedical Research Centre, Addenbrooke’s Hospital, Cambridge CB2 0QQ, United Kingdom
| | - Peter J. Voshol
- Institute of Metabolic Science, University of Cambridge Metabolic Research Laboratories and National Institute for Health Research Cambridge Biomedical Research Centre, Addenbrooke’s Hospital, Cambridge CB2 0QQ, United Kingdom
| | - Justin J. Rochford
- Institute of Metabolic Science, University of Cambridge Metabolic Research Laboratories and National Institute for Health Research Cambridge Biomedical Research Centre, Addenbrooke’s Hospital, Cambridge CB2 0QQ, United Kingdom
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96
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Obrowsky S, Chandak PG, Patankar JV, Povoden S, Schlager S, Kershaw EE, Bogner-Strauss JG, Hoefler G, Levak-Frank S, Kratky D. Adipose triglyceride lipase is a TG hydrolase of the small intestine and regulates intestinal PPARα signaling. J Lipid Res 2012; 54:425-35. [PMID: 23220585 PMCID: PMC3541705 DOI: 10.1194/jlr.m031716] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Adipose triglyceride lipase (ATGL) is the rate-limiting enzyme mediating
triglyceride (TG) hydrolysis. The lack of ATGL results in TG accumulation in
multiple tissues, underscoring the critical role of ATGL in maintaining lipid
homeostasis. Recent evidence suggests that ATGL affects TG metabolism via
activation of peroxisome proliferator-activated receptor α (PPARα).
To investigate specific effects of intestinal ATGL on lipid metabolism we
generated mice lacking ATGL exclusively in the intestine (ATGLiKO). We found
decreased TG hydrolase activity and increased intracellular TG content in
ATGLiKO small intestines. Intragastric administration of
[3H]trioleate resulted in the accumulation of radioactive TG in the
intestine, whereas absorption into the systemic circulation was unchanged.
Intraperitoneally injected [3H]oleate also accumulated within TG in
ATGLiKO intestines, indicating that ATGL mobilizes fatty acids from the systemic
circulation absorbed by the basolateral side from the blood. Down-regulation of
PPARα target genes suggested modulation of cholesterol absorption by
intestinal ATGL. Accordingly, ATGL deficiency in the intestine resulted in
delayed cholesterol absorption. Importantly, this study provides evidence that
ATGL has no impact on intestinal TG absorption but hydrolyzes TGs taken up from
the intestinal lumen and systemic circulation. Our data support the role of ATGL
in modulating PPARα-dependent processes also in the small intestine.
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Affiliation(s)
- Sascha Obrowsky
- Institute of Molecular Biology, Medical University of Graz, Graz, Austria
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97
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Chavan SS, Hudson LK, Li JH, Ochani M, Harris Y, Patel NB, Katz D, Scheinerman JA, Pavlov VA, Tracey KJ. Identification of pigment epithelium-derived factor as an adipocyte-derived inflammatory factor. Mol Med 2012; 18:1161-8. [PMID: 22714715 DOI: 10.2119/molmed.2012.00156] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Accepted: 06/14/2012] [Indexed: 12/31/2022] Open
Abstract
Obesity is a major risk factor for insulin resistance, type 2 diabetes mellitus and cardiovascular disease. The pathophysiology of obesity is associated with chronic low-grade inflammation. Adipose tissue in obesity is significantly infiltrated by macrophages that secrete cytokines. The mechanisms of interaction between macrophages and adipocytes, leading to macrophage activation and increased cytokine release, remain to be elucidated. We reasoned that an adipocyte-derived factor might stimulate activation of macrophages. We have identified pigment epithelium-derived factor (PEDF) as a mediator of inflammation that is secreted by adipocytes and mediates macrophage activation. Recombinant PEDF activates macrophages to release tumor necrosis factor (TNF) and interleukin-1 (IL-1). The PEDF receptor adipose triglyceride lipase (ATGL) is required for PEDF-mediated macrophage activation. Selective inhibition of ATGL on macrophages attenuates PEDF-induced TNF production, and PEDF enhances the phosphorylation of p38 and extracellular signal-regulated kinase 1/2 mitogen-activated protein kinases. PEDF administration to rats results in increased serum TNF levels, and insulin resistance. Together, these findings suggest that PEDF secreted by adipocytes contributes to the onset and maintenance of chronic inflammation in obesity, and may be a therapeutic target in ameliorating insulin resistance.
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Affiliation(s)
- Sangeeta S Chavan
- Laboratory of Biomedical Science, The Feinstein Institute for Medical Research, Manhasset, New York 11030, United States of America.
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98
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Radovic B, Aflaki E, Kratky D. Adipose triglyceride lipase in immune response, inflammation, and atherosclerosis. Biol Chem 2012; 393:1005-11. [PMID: 22944699 PMCID: PMC3520003 DOI: 10.1515/hsz-2012-0192] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 05/23/2012] [Indexed: 12/15/2022]
Abstract
Consistent with its central importance in lipid and energy homeostasis, lipolysis occurs in essentially all tissues and cell types, including macrophages. The hydrolytic cleavage of triacylglycerol by adipose triglyceride lipase (ATGL) generates non-esterified fatty acids, which are subsequently used as essential precursors for lipid and membrane synthesis, mediators in cell signaling processes or as energy substrate in mitochondria. This review summarizes the current knowledge concerning the consequences of ATGL deficiency in macrophages with particular emphasis on macrophage (dys)-function, apoptosis, and atherosclerosis.
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Affiliation(s)
- Branislav Radovic
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, A-8010 Graz, Austria
| | | | - Dagmar Kratky
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, A-8010 Graz, Austria
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99
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Schipper HS, Prakken B, Kalkhoven E, Boes M. Adipose tissue-resident immune cells: key players in immunometabolism. Trends Endocrinol Metab 2012; 23:407-15. [PMID: 22795937 DOI: 10.1016/j.tem.2012.05.011] [Citation(s) in RCA: 211] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 05/29/2012] [Accepted: 05/31/2012] [Indexed: 12/20/2022]
Abstract
Adipose tissue (AT) plays a pivotal role in whole-body lipid and glucose homeostasis. AT exerts metabolic control through various immunological mechanisms that instigated a new research field termed immunometabolism. Here, we review AT-resident immune cells and their role as key players in immunometabolism. In lean subjects, AT-resident immune cells have housekeeping functions ranging from apoptotic cell clearance to extracellular matrix remodeling and angiogenesis. However, obesity provides bacterial and metabolic danger signals that mimic bacterial infection, and drives a shift in immune-cell phenotypes and numbers, classified as a prototypic T helper 1 (Th1) inflammatory response. The resulting AT inflammation and insulin resistance link obesity to its metabolic sequel, and suggests that targeted immunomodulatory interventions may be beneficial for obese patients.
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Affiliation(s)
- Henk S Schipper
- Department of Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht and Center for Molecular and Cellular Intervention, Wilhelmina Children's Hospital, Utrecht, The Netherlands
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100
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Cholesteryl ester accumulation and accelerated cholesterol absorption in intestine-specific hormone sensitive lipase-null mice. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:1406-14. [PMID: 22842588 PMCID: PMC3459056 DOI: 10.1016/j.bbalip.2012.07.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 07/12/2012] [Accepted: 07/16/2012] [Indexed: 11/21/2022]
Abstract
Hormone sensitive lipase (HSL) regulates the hydrolysis of acylglycerols and cholesteryl esters (CE) in various cells and organs, including enterocytes of the small intestine. The physiological role of this enzyme in enterocytes, however, stayed elusive. In the present study we generated mice lacking HSL exclusively in the small intestine (HSLiKO) to investigate the impact of HSL deficiency on intestinal lipid metabolism and the consequences on whole body lipid homeostasis. Chow diet-fed HSLiKO mice showed unchanged plasma lipid concentrations. In addition, feeding with high fat/high cholesterol (HF/HC) diet led to unaltered triglyceride but increased plasma cholesterol concentrations and CE accumulation in the small intestine. The same effect was observed after an acute cholesterol load. Gavaging of radioactively labeled cholesterol resulted in increased abundance of radioactivity in plasma, liver and small intestine of HSLiKO mice 4 h post-gavaging. However, cholesterol absorption determined by the fecal dual-isotope ratio method revealed no significant difference, suggesting that HSLiKO mice take up the same amount of cholesterol but in an accelerated manner. mRNA expression levels of genes involved in intestinal cholesterol transport and esterification were unchanged but we observed downregulation of HMG-CoA reductase and synthase and consequently less intestinal cholesterol biosynthesis. Taken together our study demonstrates that the lack of intestinal HSL leads to CE accumulation in the small intestine, accelerated cholesterol absorption and decreased cholesterol biosynthesis, indicating that HSL plays an important role in intestinal cholesterol homeostasis.
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