1
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Hsia JZ, Liu D, Haynes L, Cruz-Cosme R, Tang Q. Lipid Droplets: Formation, Degradation, and Their Role in Cellular Responses to Flavivirus Infections. Microorganisms 2024; 12:647. [PMID: 38674592 PMCID: PMC11051834 DOI: 10.3390/microorganisms12040647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 03/18/2024] [Accepted: 03/22/2024] [Indexed: 04/28/2024] Open
Abstract
Lipid droplets (LDs) are cellular organelles derived from the endoplasmic reticulum (ER), serving as lipid storage sites crucial for maintaining cellular lipid homeostasis. Recent attention has been drawn to their roles in viral replication and their interactions with viruses. However, the precise biological functions of LDs in viral replication and pathogenesis remain incompletely understood. To elucidate the interaction between LDs and viruses, it is imperative to comprehend the biogenesis of LDs and their dynamic interactions with other organelles. In this review, we explore the intricate pathways involved in LD biogenies within the cytoplasm, encompassing the uptake of fatty acid from nutrients facilitated by CD36-mediated membranous protein (FABP/FATP)-FA complexes, and FA synthesis via glycolysis in the cytoplasm and the TCL cycle in mitochondria. While LD biogenesis primarily occurs in the ER, matured LDs are intricately linked to multiple organelles. Viral infections can lead to diverse consequences in terms of LD status within cells post-infection, potentially involving the breakdown of LDs through the activation of lipophagy. However, the exact mechanisms underlying LD destruction or accumulation by viruses remain elusive. The significance of LDs in viral replication renders them effective targets for developing broad-spectrum antivirals. Moreover, considering that reducing neutral lipids in LDs is a strategy for anti-obesity treatment, LD depletion may not pose harm to cells. This presents LDs as promising antiviral targets for developing therapeutics that are minimally or non-toxic to the host.
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Affiliation(s)
| | | | | | | | - Qiyi Tang
- Department of Microbiology, Howard University College of Medicine, Washington, DC 20059, USA; (J.Z.H.); (D.L.); (L.H.); (R.C.-C.)
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2
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Kohlmayr JM, Grabner GF, Nusser A, Höll A, Manojlović V, Halwachs B, Masser S, Jany-Luig E, Engelke H, Zimmermann R, Stelzl U. Mutational scanning pinpoints distinct binding sites of key ATGL regulators in lipolysis. Nat Commun 2024; 15:2516. [PMID: 38514628 PMCID: PMC10958042 DOI: 10.1038/s41467-024-46937-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 03/14/2024] [Indexed: 03/23/2024] Open
Abstract
ATGL is a key enzyme in intracellular lipolysis and plays an important role in metabolic and cardiovascular diseases. ATGL is tightly regulated by a known set of protein-protein interaction partners with activating or inhibiting functions in the control of lipolysis. Here, we use deep mutational protein interaction perturbation scanning and generate comprehensive profiles of single amino acid variants that affect the interactions of ATGL with its regulatory partners: CGI-58, G0S2, PLIN1, PLIN5 and CIDEC. Twenty-three ATGL amino acid variants yield a specific interaction perturbation pattern when validated in co-immunoprecipitation experiments in mammalian cells. We identify and characterize eleven highly selective ATGL switch mutations which affect the interaction of one of the five partners without affecting the others. Switch mutations thus provide distinct interaction determinants for ATGL's key regulatory proteins at an amino acid resolution. When we test triglyceride hydrolase activity in vitro and lipolysis in cells, the activity patterns of the ATGL switch variants trace to their protein interaction profile. In the context of structural data, the integration of variant binding and activity profiles provides insights into the regulation of lipolysis and the impact of mutations in human disease.
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Affiliation(s)
- Johanna M Kohlmayr
- Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, University of Graz, Graz, Austria
| | - Gernot F Grabner
- Institute of Molecular Biosciences, Biochemistry, University of Graz, Graz, Austria
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Anna Nusser
- Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, University of Graz, Graz, Austria
| | - Anna Höll
- Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, University of Graz, Graz, Austria
| | - Verina Manojlović
- Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, University of Graz, Graz, Austria
| | - Bettina Halwachs
- Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, University of Graz, Graz, Austria
- Field of Excellence BioHealth - University of Graz, Graz, Austria
| | - Sarah Masser
- Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Evelyne Jany-Luig
- Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, University of Graz, Graz, Austria
| | - Hanna Engelke
- Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, University of Graz, Graz, Austria
- Field of Excellence BioHealth - University of Graz, Graz, Austria
| | - Robert Zimmermann
- Institute of Molecular Biosciences, Biochemistry, University of Graz, Graz, Austria
- Field of Excellence BioHealth - University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Ulrich Stelzl
- Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, University of Graz, Graz, Austria.
- Field of Excellence BioHealth - University of Graz, Graz, Austria.
- BioTechMed-Graz, Graz, Austria.
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3
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Awad D, Cao PHA, Pulliam TL, Spradlin M, Subramani E, Tellman TV, Ribeiro CF, Muzzioli R, Jewell BE, Pakula H, Ackroyd JJ, Murray MM, Han JJ, Leng M, Jain A, Piyarathna B, Liu J, Song X, Zhang J, Klekers AR, Drake JM, Ittmann MM, Coarfa C, Piwnica-Worms D, Farach-Carson MC, Loda M, Eberlin LS, Frigo DE. Adipose Triglyceride Lipase Is a Therapeutic Target in Advanced Prostate Cancer That Promotes Metabolic Plasticity. Cancer Res 2024; 84:703-724. [PMID: 38038968 PMCID: PMC10939928 DOI: 10.1158/0008-5472.can-23-0555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 10/09/2023] [Accepted: 11/28/2023] [Indexed: 12/02/2023]
Abstract
Lipid metabolism plays a central role in prostate cancer. To date, the major focus has centered on de novo lipogenesis and lipid uptake in prostate cancer, but inhibitors of these processes have not benefited patients. A better understanding of how cancer cells access lipids once they are created or taken up and stored could uncover more effective strategies to perturb lipid metabolism and treat patients. Here, we identified that expression of adipose triglyceride lipase (ATGL), an enzyme that controls lipid droplet homeostasis and a previously suspected tumor suppressor, correlates with worse overall survival in men with advanced, castration-resistant prostate cancer (CRPC). Molecular, genetic, or pharmacologic inhibition of ATGL impaired human and murine prostate cancer growth in vivo and in cell culture or organoids under conditions mimicking the tumor microenvironment. Mass spectrometry imaging demonstrated that ATGL profoundly regulates lipid metabolism in vivo, remodeling membrane composition. ATGL inhibition induced metabolic plasticity, causing a glycolytic shift that could be exploited therapeutically by cotargeting both metabolic pathways. Patient-derived phosphoproteomics identified ATGL serine 404 as a target of CAMKK2-AMPK signaling in CRPC cells. Mutation of serine 404 did not alter the lipolytic activity of ATGL but did decrease CRPC growth, migration, and invasion, indicating that noncanonical ATGL activity also contributes to disease progression. Unbiased immunoprecipitation/mass spectrometry suggested that mutation of serine 404 not only disrupts existing ATGL protein interactions but also leads to new protein-protein interactions. Together, these data nominate ATGL as a therapeutic target for CRPC and provide insights for future drug development and combination therapies. SIGNIFICANCE ATGL promotes prostate cancer metabolic plasticity and progression through both lipase-dependent and lipase-independent activity, informing strategies to target ATGL and lipid metabolism for cancer treatment.
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Affiliation(s)
- Dominik Awad
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA
| | - Pham Hong Anh Cao
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA
| | - Thomas L. Pulliam
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Meredith Spradlin
- Department of Chemistry, The University of Texas at Austin, Austin, Texas, USA
- Department of Surgery, Baylor College of Medicine, Houston, Texas, USA
| | - Elavarasan Subramani
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Tristen V. Tellman
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA
- Department of Diagnostic and Biomedical Sciences, The University of Texas Health Science Center at Houston School of Dentistry, Houston, TX, USA
| | - Caroline F. Ribeiro
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Riccardo Muzzioli
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Brittany E. Jewell
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Hubert Pakula
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Jeffrey J. Ackroyd
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Mollianne M. Murray
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jenny J. Han
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Mei Leng
- Mass Spectrometry Proteomics Core, Baylor College of Medicine, Houston, TX, USA
| | - Antrix Jain
- Mass Spectrometry Proteomics Core, Baylor College of Medicine, Houston, TX, USA
| | - Badrajee Piyarathna
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
| | - Jingjing Liu
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Xingzhi Song
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jianhua Zhang
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Albert R. Klekers
- Department of Abdominal Radiology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Justin M. Drake
- Departments of Pharmacology and Urology, University of Minnesota, Minneapolis, MN, USA
- Masonic Cancer Center, University of Minnesota-Twin Cities, MN, USA
| | - Michael M. Ittmann
- Departments of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA
- Dan L. Duncan Cancer Center, Houston, TX, USA
- Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, USA
- Michael E. DeBakey Department of Surgery, Houston, TX, USA
| | - Cristian Coarfa
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
| | - David Piwnica-Worms
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Mary C. Farach-Carson
- Department of Diagnostic and Biomedical Sciences, The University of Texas Health Science Center at Houston School of Dentistry, Houston, TX, USA
| | - Massimo Loda
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Livia S. Eberlin
- Department of Surgery, Baylor College of Medicine, Houston, Texas, USA
| | - Daniel E. Frigo
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX, USA
- Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
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4
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Yu H, Niu Y, Lei X, Xie C, Yan X. Multi-Omics Analysis Reveals Sphingomyelin Accumulation, Glycerolipids Loss, and Disorders of Lipid Metabolism Regulated by Leucine Deprivation in the Liver of Mice. Mol Nutr Food Res 2024; 68:e2300567. [PMID: 38059795 DOI: 10.1002/mnfr.202300567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/27/2023] [Indexed: 12/08/2023]
Abstract
SCOPE Branched-chain amino acids, especially leucine, have been reported to play a role in regulating lipid metabolism. This study aims to examine the effects of leucine deprivation on hepatic lipid metabolism. METHODS AND RESULTS C57BL/6 mice are fed with a chow diet (control group, n = 8) or a leucine-free diet (-Leu group, n = 8) for 7 days. Histology, lipidomics, targeted metabolomics, and transcriptomics are performed to analyze the liver tissue. Compared to control group, -Leu group exhibits a notably reduced liver weight, accompanied by hepatic injury, and disorders of lipid metabolism. The level of sphingomyelin (SM) is significantly increased in the liver of -Leu group, while the glycerolipids (GL) level is significantly decreased. The expression of sphingomyelin synthase 1 (SGMS1) is upregulated by leucine deprivation in a time-dependent manner, leading to hepatic SM accumulation. Moreover, leucine deprivation results in hepatic GL loss via suppressing fatty acid synthase (FASN) and acetyl-CoA carboxylase 1 (ACC1) expression. CONCLUSION The findings demonstrate that leucine deprivation results in abnormal lipid metabolism in the liver, mainly manifested as SM accumulation and GL loss. These results provide insights into the role of leucine in regulating lipid metabolism.
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Affiliation(s)
- Haonan Yu
- National Key Laboratory of Agricultural Microbiology, Frontiers Science Center for Animal Breeding and Sustainable Production, Hubei Hongshan Laboratory, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, 430070, China
- Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei, 430070, China
| | - Yaorong Niu
- National Key Laboratory of Agricultural Microbiology, Frontiers Science Center for Animal Breeding and Sustainable Production, Hubei Hongshan Laboratory, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, 430070, China
- Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei, 430070, China
| | - Xinyu Lei
- National Key Laboratory of Agricultural Microbiology, Frontiers Science Center for Animal Breeding and Sustainable Production, Hubei Hongshan Laboratory, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, 430070, China
- Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei, 430070, China
| | - Chunlin Xie
- National Key Laboratory of Livestock and Poultry Breeding, Guangdong Key Laboratory of Animal Breeding and Nutrition, Institute of Animal Science, Guangzhou, Guangdong, 510640, China
| | - Xianghua Yan
- National Key Laboratory of Agricultural Microbiology, Frontiers Science Center for Animal Breeding and Sustainable Production, Hubei Hongshan Laboratory, College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, 430070, China
- Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan, Hubei, 430070, China
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5
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Hofer P, Grabner GF, König M, Xie H, Bulfon D, Ludwig AE, Wolinski H, Zimmermann R, Zechner R, Heier C. Cooperative lipolytic control of neuronal triacylglycerol by spastic paraplegia-associated enzyme DDHD2 and ATGL. J Lipid Res 2023; 64:100457. [PMID: 37832604 PMCID: PMC10665947 DOI: 10.1016/j.jlr.2023.100457] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 10/01/2023] [Accepted: 10/04/2023] [Indexed: 10/15/2023] Open
Abstract
Intracellular lipolysis-the enzymatic breakdown of lipid droplet-associated triacylglycerol (TAG)-depends on the cooperative action of several hydrolytic enzymes and regulatory proteins, together designated as lipolysome. Adipose triglyceride lipase (ATGL) acts as a major cellular TAG hydrolase and core effector of the lipolysome in many peripheral tissues. Neurons initiate lipolysis independently of ATGL via DDHD domain-containing 2 (DDHD2), a multifunctional lipid hydrolase whose dysfunction causes neuronal TAG deposition and hereditary spastic paraplegia. Whether and how DDHD2 cooperates with other lipolytic enzymes is currently unknown. In this study, we further investigated the enzymatic properties and functions of DDHD2 in neuroblastoma cells and primary neurons. We found that DDHD2 hydrolyzes multiple acylglycerols in vitro and substantially contributes to neutral lipid hydrolase activities of neuroblastoma cells and brain tissue. Substrate promiscuity of DDHD2 allowed its engagement at different steps of the lipolytic cascade: In neuroblastoma cells, DDHD2 functioned exclusively downstream of ATGL in the hydrolysis of sn-1,3-diacylglycerol (DAG) isomers but was dispensable for TAG hydrolysis and lipid droplet homeostasis. In primary cortical neurons, DDHD2 exhibited lipolytic control over both, DAG and TAG, and complemented ATGL-dependent TAG hydrolysis. We conclude that neuronal cells use noncanonical configurations of the lipolysome and engage DDHD2 as dual TAG/DAG hydrolase in cooperation with ATGL.
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Affiliation(s)
- Peter Hofer
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Gernot F Grabner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Mario König
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Hao Xie
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; State Key Laboratory of Natural Medicines, Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing, China
| | - Dominik Bulfon
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Anton E Ludwig
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Heimo Wolinski
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria
| | - Robert Zimmermann
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Christoph Heier
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioHealth Field of Excellence, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria.
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6
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Guerrero-Santoro J, Morizane M, Oh SY, Mishima T, Goff JP, Bildirici I, Sadovsky E, Ouyang Y, Tyurin VA, Tyurina YY, Kagan VE, Sadovsky Y. The lipase cofactor CGI58 controls placental lipolysis. JCI Insight 2023; 8:168717. [PMID: 37212279 DOI: 10.1172/jci.insight.168717] [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: 01/10/2023] [Accepted: 04/12/2023] [Indexed: 05/23/2023] Open
Abstract
In eutherians, the placenta plays a critical role in the uptake, storage, and metabolism of lipids. These processes govern the availability of fatty acids to the developing fetus, where inadequate supply has been associated with substandard fetal growth. Whereas lipid droplets are essential for the storage of neutral lipids in the placenta and many other tissues, the processes that regulate placental lipid droplet lipolysis remain largely unknown. To assess the role of triglyceride lipases and their cofactors in determining placental lipid droplet and lipid accumulation, we assessed the role of patatin like phospholipase domain containing 2 (PNPLA2) and comparative gene identification-58 (CGI58) in lipid droplet dynamics in the human and mouse placenta. While both proteins are expressed in the placenta, the absence of CGI58, not PNPLA2, markedly increased placental lipid and lipid droplet accumulation. These changes were reversed upon restoration of CGI58 levels selectively in the CGI58-deficient mouse placenta. Using co-immunoprecipitation, we found that, in addition to PNPLA2, PNPLA9 interacts with CGI58. PNPLA9 was dispensable for lipolysis in the mouse placenta yet contributed to lipolysis in human placental trophoblasts. Our findings establish a crucial role for CGI58 in placental lipid droplet dynamics and, by extension, in nutrient supply to the developing fetus.
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Affiliation(s)
- Jennifer Guerrero-Santoro
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Mayumi Morizane
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Soo-Young Oh
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Takuya Mishima
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Julie P Goff
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Ibrahim Bildirici
- Department of Obstetrics and Gynecology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Elena Sadovsky
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Yingshi Ouyang
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Vladimir A Tyurin
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health
| | - Yulia Y Tyurina
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health
| | - Valerian E Kagan
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health
- Department of Chemistry
- Department of Pharmacology and Chemical Biology
- Department of Radiation Oncology; and
| | - Yoel Sadovsky
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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7
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Lahree A, Mello-Vieira J, Mota MM. The nutrient games - Plasmodium metabolism during hepatic development. Trends Parasitol 2023; 39:445-460. [PMID: 37061442 DOI: 10.1016/j.pt.2023.03.013] [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: 10/22/2022] [Revised: 03/15/2023] [Accepted: 03/17/2023] [Indexed: 04/17/2023]
Abstract
Malaria is a febrile illness caused by species of the protozoan parasite Plasmodium and is characterized by recursive infections of erythrocytes, leading to clinical symptoms and pathology. In mammals, Plasmodium parasites undergo a compulsory intrahepatic development stage before infecting erythrocytes. Liver-stage parasites have a metabolic configuration to facilitate the replication of several thousand daughter parasites. Their metabolism is of interest to identify cellular pathways essential for liver infection, to kill the parasite before onset of the disease. In this review, we summarize the current knowledge on nutrient acquisition and biosynthesis by liver-stage parasites mostly generated in murine malaria models, gaps in knowledge, and challenges to create a holistic view of the development and deficiencies in this field.
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Affiliation(s)
- Aparajita Lahree
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - João Mello-Vieira
- Institute of Biochemistry II, School of Medicine, Goethe University Frankfurt, Frankfurt am Main, Germany; Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Maria M Mota
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal.
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8
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Li X, Liu Q, Pan Y, Chen S, Zhao Y, Hu Y. New insights into the role of dietary triglyceride absorption in obesity and metabolic diseases. Front Pharmacol 2023; 14:1097835. [PMID: 36817150 PMCID: PMC9932209 DOI: 10.3389/fphar.2023.1097835] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 01/20/2023] [Indexed: 02/05/2023] Open
Abstract
The incidence of obesity and associated metabolic diseases is increasing globally, adversely affecting human health. Dietary fats, especially triglycerides, are an important source of energy for the body, and the intestine absorbs lipids through a series of orderly and complex steps. A long-term high-fat diet leads to intestinal dysfunction, inducing obesity and metabolic disorders. Therefore, regulating dietary triglycerides absorption is a promising therapeutic strategy. In this review, we will discuss diverse aspects of the dietary triglycerides hydrolysis, fatty acid uptake, triglycerides resynthesis, chylomicron assembly, trafficking, and secretion processes in intestinal epithelial cells, as well as potential targets in this process that may influence dietary fat-induced obesity and metabolic diseases. We also mention the possible shortcomings and deficiencies in modulating dietary lipid absorption targets to provide a better understanding of their administrability as drugs in obesity and related metabolic disorders.
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Affiliation(s)
- Xiaojing Li
- Key Laboratory of Liver and Kidney Diseases (Ministry of Education), Institute of Liver Diseases, Shanghai Key Laboratory of Traditional Chinese Clinical Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Qiaohong Liu
- Institute of Clinical Pharmacology, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yuqing Pan
- Key Laboratory of Liver and Kidney Diseases (Ministry of Education), Institute of Liver Diseases, Shanghai Key Laboratory of Traditional Chinese Clinical Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Si Chen
- Key Laboratory of Liver and Kidney Diseases (Ministry of Education), Institute of Liver Diseases, Shanghai Key Laboratory of Traditional Chinese Clinical Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yu Zhao
- Key Laboratory of Liver and Kidney Diseases (Ministry of Education), Institute of Liver Diseases, Shanghai Key Laboratory of Traditional Chinese Clinical Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China,*Correspondence: Yu Zhao, ; Yiyang Hu,
| | - Yiyang Hu
- Key Laboratory of Liver and Kidney Diseases (Ministry of Education), Institute of Liver Diseases, Shanghai Key Laboratory of Traditional Chinese Clinical Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China,Institute of Clinical Pharmacology, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China,*Correspondence: Yu Zhao, ; Yiyang Hu,
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9
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Heden TD, Chen C, Leland G, Mashek MM, Najt CP, Shang L, Chow LS, Mashek DG. Isolated and combined impact of dietary olive oil and exercise on markers of health and energy metabolism in female mice. J Nutr Biochem 2022; 107:109040. [PMID: 35533899 PMCID: PMC9626252 DOI: 10.1016/j.jnutbio.2022.109040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 03/04/2022] [Accepted: 03/20/2022] [Indexed: 11/27/2022]
Abstract
An olive oil (OO) rich diet or high-intensity interval training (HIIT) independently improve markers of health and energy metabolism, but it is unknown if combining OO and HIIT synergize to improve these markers. This study characterized the isolated and combined impact of OO and HIIT on markers of health and energy metabolism in various tissues in C57BL/6J female mice. Nine-week-old mice were divided into four groups for a 12-week diet and/or exercise intervention including: (1) Control Diet without HIIT (CD), (2) Control Diet with HIIT (CD+HIIT), (3) OO diet (10% kcal from olive oil) without HIIT, and (4) OO diet with HIIT (OO+HIIT). Neither dietary OO or HIIT altered body weight, glucose tolerance, or serum lipids. HIIT, regardless of diet, increased aerobic capacity and HDL cholesterol levels. In liver and heart tissue, OO resulted in similar adaptations as HIIT including increased mitochondrial content and fatty acid oxidation but combining OO with HIIT did not augment these effects. In skeletal muscle, HIIT increased mitochondrial content in type II fibers similarly between diets. An RNA sequencing analysis on type I fibers revealed OO reduced muscle regeneration and lipid metabolism gene abundance, whereas HIIT increased the abundance of these genes, independent of diet. HIIT training, independent of diet, induced subcutaneous white adipose tissue (sWAT) hypertrophy, whereas OO induced gonadal white adipose tissue (gWAT) hypertrophy, an effect that was augmented with HIIT. These data highlight the pleiotropic effects of OO and HIIT, although their combination does not synergize to further improve most markers of health and energy metabolism.
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Affiliation(s)
- Timothy D Heden
- Department of Biochemistry, Molecular Biology, and Biophysics, Minneapolis, MN
| | - Chen Chen
- Department of Biochemistry, Molecular Biology, and Biophysics, Minneapolis, MN
| | - Grace Leland
- Department of Biochemistry, Molecular Biology, and Biophysics, Minneapolis, MN
| | - Mara M Mashek
- Department of Biochemistry, Molecular Biology, and Biophysics, Minneapolis, MN
| | - Charles P Najt
- Department of Biochemistry, Molecular Biology, and Biophysics, Minneapolis, MN
| | - Linshan Shang
- Department of Biochemistry, Molecular Biology, and Biophysics, Minneapolis, MN
| | - Lisa S Chow
- Department of Medicine, Division of Diabetes, Endocrinology, and Metabolism, Minneapolis, MN
| | - Douglas G Mashek
- Department of Biochemistry, Molecular Biology, and Biophysics, Minneapolis, MN; Department of Medicine, Division of Diabetes, Endocrinology, and Metabolism, Minneapolis, MN.
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10
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Seibert JT, Najt CP, Heden TD, Mashek DG, Chow LS. Muscle Lipid Droplets: Cellular Signaling to Exercise Physiology and Beyond. Trends Endocrinol Metab 2020; 31:928-938. [PMID: 32917515 PMCID: PMC7704552 DOI: 10.1016/j.tem.2020.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/09/2020] [Accepted: 08/13/2020] [Indexed: 12/21/2022]
Abstract
Conventionally viewed as energy storage depots, lipid droplets (LDs) play a central role in muscle lipid metabolism and intracellular signaling, as recognized by recent advances in our biological understanding. Specific subpopulations of muscle LDs, defined by location and associated proteins, are responsible for distinct biological functions. In this review, the traditional view of muscle LDs is examined, and the emerging role of LDs in intracellular signaling is highlighted. The effects of chronic and acute exercise on muscle LD metabolism and signaling is discussed. In conclusion, future directions for muscle LD research are identified. The primary focus will be on human studies, with inclusion of select animal/cellular/non-muscle studies as appropriate, to provide the underlying mechanisms driving the observed findings.
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Affiliation(s)
- Jacob T Seibert
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Charles P Najt
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Timothy D Heden
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Douglas G Mashek
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, University of Minnesota, Minneapolis, MN 55455, USA
| | - Lisa S Chow
- Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, University of Minnesota, Minneapolis, MN 55455, USA.
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11
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Raje V, Ahern KW, Martinez BA, Howell NL, Oenarto V, Granade ME, Kim JW, Tundup S, Bottermann K, Gödecke A, Keller SR, Kadl A, Bland ML, Harris TE. Adipocyte lipolysis drives acute stress-induced insulin resistance. Sci Rep 2020; 10:18166. [PMID: 33097799 PMCID: PMC7584576 DOI: 10.1038/s41598-020-75321-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 10/09/2020] [Indexed: 12/12/2022] Open
Abstract
Stress hyperglycemia and insulin resistance are evolutionarily conserved metabolic adaptations to severe injury including major trauma, burns, or hemorrhagic shock (HS). In response to injury, the neuroendocrine system increases secretion of counterregulatory hormones that promote rapid mobilization of nutrient stores, impair insulin action, and ultimately cause hyperglycemia, a condition known to impair recovery from injury in the clinical setting. We investigated the contributions of adipocyte lipolysis to the metabolic response to acute stress. Both surgical injury with HS and counterregulatory hormone (epinephrine) infusion profoundly stimulated adipocyte lipolysis and simultaneously triggered insulin resistance and hyperglycemia. When lipolysis was inhibited, the stress-induced insulin resistance and hyperglycemia were largely abolished demonstrating an essential requirement for adipocyte lipolysis in promoting stress-induced insulin resistance. Interestingly, circulating non-esterified fatty acid levels did not increase with lipolysis or correlate with insulin resistance during acute stress. Instead, we show that impaired insulin sensitivity correlated with circulating levels of the adipokine resistin in a lipolysis-dependent manner. Our findings demonstrate the central importance of adipocyte lipolysis in the metabolic response to injury. This insight suggests new approaches to prevent insulin resistance and stress hyperglycemia in trauma and surgery patients and thereby improve outcomes.
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Affiliation(s)
- Vidisha Raje
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Katelyn W Ahern
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Brittany A Martinez
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Nancy L Howell
- Department of Medicine, Endocrinology and Metabolism, University of Virginia, Charlottesville, VA, USA
| | - Vici Oenarto
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.,Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Mitchell E Granade
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Jae Woo Kim
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Smanla Tundup
- Department of Medicine, Pulmonary and Critical Care Medicine, University of Virginia, Charlottesville, VA, USA
| | | | - Axel Gödecke
- Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Susanna R Keller
- Department of Medicine, Endocrinology and Metabolism, University of Virginia, Charlottesville, VA, USA
| | - Alexandra Kadl
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.,Department of Medicine, Pulmonary and Critical Care Medicine, University of Virginia, Charlottesville, VA, USA
| | - Michelle L Bland
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Thurl E Harris
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.
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12
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Sukhorukov VN, Khotina VA, Chegodaev YS, Ivanova E, Sobenin IA, Orekhov AN. Lipid Metabolism in Macrophages: Focus on Atherosclerosis. Biomedicines 2020; 8:biomedicines8080262. [PMID: 32752275 PMCID: PMC7459513 DOI: 10.3390/biomedicines8080262] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/26/2020] [Accepted: 07/27/2020] [Indexed: 12/18/2022] Open
Abstract
Mechanisms of lipid homeostasis and its impairment are of crucial importance for atherogenesis, and their understanding is necessary for successful development of new therapeutic approaches. In the arterial wall, macrophages play a prominent role in intracellular lipid accumulation, giving rise to foam cells that populate growing atherosclerotic plaques. Under normal conditions, macrophages are able to process substantial amounts of lipids and cholesterol without critical overload of the catabolic processes. However, in atherosclerosis, these pathways become inefficient, leading to imbalance in cholesterol and lipid metabolism and disruption of cellular functions. In this review, we summarize the existing knowledge on the involvement of macrophage lipid metabolism in atherosclerosis development, including both the results of recent studies and classical concepts, and provide a detailed description of these processes from the moment of lipid uptake with lipoproteins to cholesterol efflux.
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Affiliation(s)
- Vasily N. Sukhorukov
- Research Institute of Human Morphology, Laboratory of Cellular and Molecular Pathology of Cardiovascular System, 3 Tsyurupy Str., 117418 Moscow, Russia; (V.A.K.); (I.A.S.); (A.N.O.)
- Russian Medical Research Center of Cardiology, Institute of Experimental Cardiology, Laboratory of Medical Genetics, 15-a 3-rd Cherepkovskaya Str., 121552 Moscow, Russia
- Correspondence: ; Tel.: +7-915-393-3263
| | - Victoria A. Khotina
- Research Institute of Human Morphology, Laboratory of Cellular and Molecular Pathology of Cardiovascular System, 3 Tsyurupy Str., 117418 Moscow, Russia; (V.A.K.); (I.A.S.); (A.N.O.)
- Institute of General Pathology and Pathophysiology, Laboratory of Angiopathology, 8 Baltiyskaya Str., 125315 Moscow, Russia
| | | | - Ekaterina Ivanova
- Institute for Atherosclerosis Research, Skolkovo Innovative Center, 121609 Moscow, Russia;
| | - Igor A. Sobenin
- Research Institute of Human Morphology, Laboratory of Cellular and Molecular Pathology of Cardiovascular System, 3 Tsyurupy Str., 117418 Moscow, Russia; (V.A.K.); (I.A.S.); (A.N.O.)
- Russian Medical Research Center of Cardiology, Institute of Experimental Cardiology, Laboratory of Medical Genetics, 15-a 3-rd Cherepkovskaya Str., 121552 Moscow, Russia
| | - Alexander N. Orekhov
- Research Institute of Human Morphology, Laboratory of Cellular and Molecular Pathology of Cardiovascular System, 3 Tsyurupy Str., 117418 Moscow, Russia; (V.A.K.); (I.A.S.); (A.N.O.)
- Institute of General Pathology and Pathophysiology, Laboratory of Angiopathology, 8 Baltiyskaya Str., 125315 Moscow, Russia
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13
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Kintscher U, Foryst-Ludwig A, Haemmerle G, Zechner R. The Role of Adipose Triglyceride Lipase and Cytosolic Lipolysis in Cardiac Function and Heart Failure. CELL REPORTS MEDICINE 2020; 1:100001. [PMID: 33205054 PMCID: PMC7659492 DOI: 10.1016/j.xcrm.2020.100001] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Heart failure is one of the leading causes of death worldwide. New therapeutic concepts are urgently required to lower the burden of heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF), the two major forms of heart failure. Lipolytic processes are induced during the development of heart failure and occur in adipose tissue and multiple organs, including the heart. Increasing evidence suggests that cellular lipolysis, in particular, adipose triglyceride lipase (ATGL) activity, has an important function in cardiac (patho)physiology. This review summarizes the crucial role of cellular lipolysis for normal cardiac function and for the development of HFrEF and HFpEF. We discuss the most relevant pre-clinical studies and elaborate on the cardiac consequences of non-myocardial and myocardial lipolysis modulation. Finally, we critically analyze the therapeutic importance of pharmacological ATGL inhibition as a potential treatment option for HFrEF and/or HFpEF in the future.
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Affiliation(s)
- Ulrich Kintscher
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Berlin, Germany
- Corresponding author
| | - Anna Foryst-Ludwig
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Berlin, Germany
| | - Guenter Haemmerle
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
- Einstein BIH Visiting Fellow, Berlin Institute of Health, and Charité - Universitätsmedizin Berlin, Berlin, Germany
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14
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Trites MJ, Clugston RD. The role of adipose triglyceride lipase in lipid and glucose homeostasis: lessons from transgenic mice. Lipids Health Dis 2019; 18:204. [PMID: 31757217 PMCID: PMC6874817 DOI: 10.1186/s12944-019-1151-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/07/2019] [Indexed: 12/14/2022] Open
Abstract
The ability of mammals to store and draw on fat reserves has been a driving force throughout evolution in an environment with intermittent nutrient availability. The discovery of adipose triglyceride lipase (ATGL) as a triglyceride lipase provided a heightened understanding of the mechanisms governing mobilization of fat reserves from adipose tissue. ATGL catalyses the initial step in adipose triglyceride lipolysis, working in concert with other enzymes to mobilize triglyceride for energy production. In addition to the role of ATGL in adipose tissue triglyceride mobilization, ATGL plays crucial roles in regulating lipid homeostasis in other tissues. These roles have been characterized primarily using transgenic mice with tissue-specific ATGL ablation. For example, the global ATGL knockout induces a severe cardiac defect that results in premature mortality that is mimicked by inducible cardiomyocyte-specific ATGL knockout. Global- and adipose-specific ATGL ablation induces a whole-body shift from lipid metabolism to glucose metabolism to satisfy metabolic demand primarily facilitated by an increase in glucose uptake by skeletal muscle. Generation of liver-specific ATGL knockouts has implicated hepatic lipolysis as a critical component of normal liver function. Analysis of β-cell ATGL knockouts implicates the necessity of pancreatic ATGL in insulin secretion. The objective of this review is to discuss the contributions of ATGL to systemic lipid- and glucose-homeostasis discovered through the study of transgenic mice.
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Affiliation(s)
- Michael J Trites
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada.,Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Robin D Clugston
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada. .,Group on the Molecular and Cell Biology of Lipids, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
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15
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Jarc E, Petan T. Lipid Droplets and the Management of Cellular Stress. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2019; 92:435-452. [PMID: 31543707 PMCID: PMC6747940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Lipid droplets are cytosolic fat storage organelles present in most eukaryotic cells. Long regarded merely as inert fat reservoirs, they are now emerging as major regulators of cellular metabolism. They act as hubs that coordinate the pathways of lipid uptake, distribution, storage, and use in the cell. Recent studies have revealed that they are also essential components of the cellular stress response. One of the hallmark characteristics of lipid droplets is their capacity to buffer excess lipids and to finely tune their subsequent release based on specific cellular requirements. This simple feature of lipid droplet biology, buffering and delayed release of lipids, forms the basis for their pleiotropic roles in the cellular stress response. In stressed cells, lipid droplets maintain energy and redox homeostasis and protect against lipotoxicity by sequestering toxic lipids into their neutral lipid core. Their mobility and dynamic interactions with mitochondria enable an efficient delivery of fatty acids for optimal energy production. Lipid droplets are also involved in the maintenance of membrane and organelle homeostasis by regulating membrane composition, preventing lipid peroxidation and removing damaged proteins and lipids. Finally, they also engage in a symbiotic relationship with autophagy and act as reservoirs of bioactive lipids that regulate inflammation and immunity. Thus, lipid droplets are central managers of lipid metabolism that function as safeguards against various types of cellular stress.
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Affiliation(s)
- Eva Jarc
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia,Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Toni Petan
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia,To whom all correspondence should be addressed: Toni Petan, Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia; Tel: +386 1 477 3713, Fax: +386 1 477 3984,
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16
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Assessment of the Main Compounds of the Lipolytic System in Treadmill Running Rats: Different Response Patterns between the Right and Left Ventricle. Int J Mol Sci 2019; 20:ijms20102556. [PMID: 31137663 PMCID: PMC6566686 DOI: 10.3390/ijms20102556] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 05/09/2019] [Accepted: 05/22/2019] [Indexed: 12/22/2022] Open
Abstract
The aim of the present study was to investigate the time and intensity dependent effects of exercise on the heart components of the lipolytic complex. Wistar rats ran on a treadmill with the speed of 18 m/min for 30 min (M30) or 120 min (M120) or with the speed of 28 m/min for 30 min (F30). The mRNA and protein expressions of the compounds adipose triglyceride lipase (ATGL), comparative gene identification-58 (CGI-58), G0/G1 switch gene 2 (G0S2), hormone sensitive lipase (HSL) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) were examined by real-time PCR and Western blot, respectively. Lipid content of free fatty acids (FFA), diacylglycerols (DG) and triacylglycerols (TG) were estimated by gas liquid chromatography. We observed virtually no changes in the left ventricle lipid contents and only minor fluctuations in its ATGL mRNA levels. This was in contrast with its right counterpart i.e., the content of TG and DG decreased in response to both increased duration and intensity of a run. This occurred in tandem with increased mRNA expression for ATGL, CGI-58 and decreased expression of G0S2. It is concluded that exercise affects behavior of the components of the lipolytic system and the lipid content in the heart ventricles. However, changes observed in the left ventricle did not mirror those in the right one.
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17
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Russell JA, Brunton PJ. Giving a good start to a new life via maternal brain allostatic adaptations in pregnancy. Front Neuroendocrinol 2019; 53:100739. [PMID: 30802468 DOI: 10.1016/j.yfrne.2019.02.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/29/2019] [Accepted: 02/21/2019] [Indexed: 12/23/2022]
Abstract
Successful pregnancy requires adjustments to multiple maternal homeostatic mechanisms, governed by the maternal brain to support and enable survival of the growing fetus and placenta. Such adjustments fit the concept of allostasis (stability through change) and have a cost: allostatic load. Allostasis is driven by ovarian, anterior pituitary, placental and feto-placental hormones acting on the maternal brain to promote adaptations that support the pregnancy and protect the fetus. Many women carry an existing allostatic load into pregnancy, from socio-economic circumstances, poor mental health and in 'developed' countries, also from obesity. These pregnancies have poorer outcomes indicating negative interactions (failing allostasis) between pre-pregnancy and pregnancy allostatic loads. Use of animal models, such as adult prenatally stressed female offspring with abnormal neuroendocrine, metabolic and behavioural phenotypes, to probe gene expression changes, and epigenetic mechanisms in the maternal brain in adverse pregnancies are discussed, with the prospect of ameliorating poor pregnancy outcomes.
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Affiliation(s)
- John A Russell
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, Scotland, UK
| | - Paula J Brunton
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, Scotland, UK; Zhejiang University-University of Edinburgh Institute, Haining, Zhejiang, PR China.
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18
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Ma S, Huang Q, Tominaga T, Liu C, Suzuki K. An 8-Week Ketogenic Diet Alternated Interleukin-6, Ketolytic and Lipolytic Gene Expression, and Enhanced Exercise Capacity in Mice. Nutrients 2018; 10:E1696. [PMID: 30405021 PMCID: PMC6266160 DOI: 10.3390/nu10111696] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/01/2018] [Accepted: 11/03/2018] [Indexed: 01/04/2023] Open
Abstract
Adjusting dietary fat intake is reported to affect mitochondrial biogenesis and fatty acid oxidation (FAO), and thus may enhance exercise capacity. However, a high-fat diet where carbohydrate intake is not limited enough also makes it difficult for athletes to maintain weight, and may fail to force the body to utilize fat. As such, a low-carbohydrate, high-fat, ketogenic diet (KD) may be viable. We have previously reported that an eight-week KD enhances exercise capacity, and suggested the mechanism to be enhanced lipolysis and ketolysis. In the present study, we investigated how an eight-week KD alters mRNA expression during fatty acid mobilization, FAO and ketolysis. We found that an eight-week KD may remodel the lipid metabolism profile, thus contributing to influence exercise capacity. We also found that ketolysis, lipolysis and FAO adaptations may contribute to enhanced exhaustive exercise performance. Along with enhanced FAO capacity during exhaustive exercise, a KD may also alter IL-6 synthesis and secretion profile, thus contribute to fatty acid mobilization, ketolysis, lipolysis and preventing muscle damage. Both the lipid metabolism response and IL-6 secretion appeared to be muscle fiber specific. Taken together, the previous and present results reveal that an eight-week KD may enhance exercise performance by up-regulating ketolysis and FAO ability. Therefore, a KD may have the potential to prevent muscle damage by altering IL-6 secretion profile, indicating that a KD may be a promising dietary approach in endurance athletes, sports, and for injury prevention.
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Affiliation(s)
- Sihui Ma
- Graduate School of Sport Sciences, Waseda University, Tokorozawa 359-1192, Japan.
| | - Qingyi Huang
- Graduate School of Sport Sciences, Waseda University, Tokorozawa 359-1192, Japan.
- College of Food Science, South China Agricultural University, Guangzhou 510642, China.
- The Key Laboratory of Food Quality and Safety of Guangdong Province, Guangzhou 510642, China.
| | - Takaki Tominaga
- College of Food Science, South China Agricultural University, Guangzhou 510642, China.
| | - Chunhong Liu
- College of Food Science, South China Agricultural University, Guangzhou 510642, China.
- The Key Laboratory of Food Quality and Safety of Guangdong Province, Guangzhou 510642, China.
| | - Katsuhiko Suzuki
- Faculty of Sport Sciences, Waseda University, Tokorozawa 359-1192, Japan.
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19
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Of mice and men: The physiological role of adipose triglyceride lipase (ATGL). Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:880-899. [PMID: 30367950 PMCID: PMC6439276 DOI: 10.1016/j.bbalip.2018.10.008] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 12/12/2022]
Abstract
Adipose triglyceride lipase (ATGL) has been discovered 14 years ago and revised our view on intracellular triglyceride (TG) mobilization – a process termed lipolysis. ATGL initiates the hydrolysis of TGs to release fatty acids (FAs) that are crucial energy substrates, precursors for the synthesis of membrane lipids, and ligands of nuclear receptors. Thus, ATGL is a key enzyme in whole-body energy homeostasis. In this review, we give an update on how ATGL is regulated on the transcriptional and post-transcriptional level and how this affects the enzymes' activity in the context of neutral lipid catabolism. In depth, we highlight and discuss the numerous physiological functions of ATGL in lipid and energy metabolism. Over more than a decade, different genetic mouse models lacking or overexpressing ATGL in a cell- or tissue-specific manner have been generated and characterized. Moreover, pharmacological studies became available due to the development of a specific murine ATGL inhibitor (Atglistatin®). The identification of patients with mutations in the human gene encoding ATGL and their disease spectrum has underpinned the importance of ATGL in humans. Together, mouse models and human data have advanced our understanding of the physiological role of ATGL in lipid and energy metabolism in adipose and non-adipose tissues, and of the pathophysiological consequences of ATGL dysfunction in mice and men. Summary of mouse models with genetic or pharmacological manipulation of ATGL. Summary of patients with mutations in the human gene encoding ATGL. In depth discussion of the role of ATGL in numerous physiological processes in mice and men.
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20
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Petan T, Jarc E, Jusović M. Lipid Droplets in Cancer: Guardians of Fat in a Stressful World. Molecules 2018; 23:molecules23081941. [PMID: 30081476 PMCID: PMC6222695 DOI: 10.3390/molecules23081941] [Citation(s) in RCA: 217] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 07/31/2018] [Accepted: 08/01/2018] [Indexed: 12/12/2022] Open
Abstract
Cancer cells possess remarkable abilities to adapt to adverse environmental conditions. Their survival during severe nutrient and oxidative stress depends on their capacity to acquire extracellular lipids and the plasticity of their mechanisms for intracellular lipid synthesis, mobilisation, and recycling. Lipid droplets, cytosolic fat storage organelles present in most cells from yeast to men, are emerging as major regulators of lipid metabolism, trafficking, and signalling in various cells and tissues exposed to stress. Their biogenesis is induced by nutrient and oxidative stress and they accumulate in various cancers. Lipid droplets act as switches that coordinate lipid trafficking and consumption for different purposes in the cell, such as energy production, protection against oxidative stress or membrane biogenesis during rapid cell growth. They sequester toxic lipids, such as fatty acids, cholesterol and ceramides, thereby preventing lipotoxic cell damage and engage in a complex relationship with autophagy. Here, we focus on the emerging mechanisms of stress-induced lipid droplet biogenesis; their roles during nutrient, lipotoxic, and oxidative stress; and the relationship between lipid droplets and autophagy. The recently discovered principles of lipid droplet biology can improve our understanding of the mechanisms that govern cancer cell adaptability and resilience to stress.
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Affiliation(s)
- Toni Petan
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia.
| | - Eva Jarc
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia.
- Jožef Stefan International Postgraduate School, Ljubljana SI-1000, Slovenia.
| | - Maida Jusović
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia.
- Jožef Stefan International Postgraduate School, Ljubljana SI-1000, Slovenia.
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21
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Quiroga AD, Lehner R. Pharmacological intervention of liver triacylglycerol lipolysis: The good, the bad and the ugly. Biochem Pharmacol 2018; 155:233-241. [PMID: 30006193 DOI: 10.1016/j.bcp.2018.07.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/09/2018] [Indexed: 02/07/2023]
Abstract
Excessive triacylglycerol (TG) accumulation is the distinctive feature of obesity. In the liver, sustained TG accretion leads to nonalcoholic fatty liver disease (NAFLD), eventually progressing to non-alcoholic steatohepatitis (NASH) and cirrhosis, which is associated with complications including hepatic failure, hepatocellular carcinoma and death. Pharmacological interventions are actively pursued to prevent lipid accumulation in hepatocytes and, therefore, to ameliorate the associated pathophysiological conditions. Here, we sought to provide an overview of the pharmacological approaches to up- or downregulate the expression and activities of the enzymes involved in hepatic TG hydrolysis. Fatty acids (FA) released by hydrolysis of hepatic TG can be used for β-oxidation, signaling, and for very low-density lipoprotein (VLDL)-TG synthesis. Originally, lipolysis was believed to be centered in the adipose and to be catalyzed by only two lipases, hormone-sensitive lipase (HSL) and monoacylglycerol lipase (MAGL). However, genetic ablation of HSL expression in mice failed to erase TG hydrolysis in adipocytes leading to the identification of a third lipase termed adipose triglyceride lipase (ATGL). Although these three enzymes are considered to be the main players governing lipolysis in the adipocyte, other lipolytic enzymes have been described to contribute to hepatic TG metabolism. These include adiponutrin/patatin-like phospholipase domain containing 3 (PNPLA3), some members of the carboxylesterase family (CES/Ces), arylacetamide deacetylase (AADAC), lysosomal acid lipase (LAL) and hepatic lipase (HL). This review highlights the consequences of pharmacological interventions of liver lipases that degrade TG in cytosolic lipid droplets, in the endoplasmic reticulum, in the late endosomes/lysosomes and along the secretory route.
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Affiliation(s)
- Ariel D Quiroga
- Instituto de Fisiología Experimental (IFISE), Área Morfología, Facultad de Ciencias Bioquímicas y Farmacéuticas, CONICET, UNR, Rosario, Argentina.
| | - Richard Lehner
- Group on Molecular and Cell Biology of Lipids, Department of Pediatrics, Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada.
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22
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Lettieri-Barbato D, Cannata SM, Casagrande V, Ciriolo MR, Aquilano K. Time-controlled fasting prevents aging-like mitochondrial changes induced by persistent dietary fat overload in skeletal muscle. PLoS One 2018; 13:e0195912. [PMID: 29742122 PMCID: PMC5942780 DOI: 10.1371/journal.pone.0195912] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 04/02/2018] [Indexed: 01/07/2023] Open
Abstract
A large body of evidence suggests that persistent dietary fat overload causes mitochondrial dysfunction and systemic metabolic gridlock. Mitochondrial and lipid metabolism in skeletal muscle (SkM) are severely affected upon persistent high fat diet (HFD) leading to premature tissue aging. Here, we designed weekly cycles of fasting (called as time-controlled fasting, TCF) and showed that they were effective in limiting mitochondrial damage and metabolic disturbances induced by HFD. Specifically, TCF was able to prevent the decline of adipose triglyceride lipase (Atgl), maintain efficient mitochondrial respiration in SkM as well as improve blood glucose and lipid profile. Atgl was found to be the mediator of such preventive effects as its downregulation or up-regulation in C2C12 myotubes triggers mitochondrial alteration or protects against the deleterious effects of high fat levels respectively. In conclusion, TCF could represent an effective strategy to limit mitochondrial impairment and metabolic inflexibility that are typically induced by modern western diets or during aging.
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Affiliation(s)
| | | | | | - Maria Rosa Ciriolo
- University of Rome Tor Vergata, Dept. Biology, Rome, Italy
- IRCCS San Raffaele La Pisana, Rome, Italy
| | - Katia Aquilano
- University of Rome Tor Vergata, Dept. Biology, Rome, Italy
- * E-mail: (KA); (DL)
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23
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Jarc E, Kump A, Malavašič P, Eichmann TO, Zimmermann R, Petan T. Lipid droplets induced by secreted phospholipase A2 and unsaturated fatty acids protect breast cancer cells from nutrient and lipotoxic stress. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:247-265. [DOI: 10.1016/j.bbalip.2017.12.006] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/13/2017] [Accepted: 12/07/2017] [Indexed: 12/12/2022]
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24
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Summers MA, Rupasinghe T, Vasiljevski ER, Evesson FJ, Mikulec K, Peacock L, Quinlan KGR, Cooper ST, Roessner U, Stevenson DA, Little DG, Schindeler A. Dietary intervention rescues myopathy associated with neurofibromatosis type 1. Hum Mol Genet 2017; 27:577-588. [DOI: 10.1093/hmg/ddx423] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 11/29/2017] [Indexed: 02/07/2023] Open
Affiliation(s)
- Matthew A Summers
- Orthopaedic Research & Biotechnology, The Children’s Hospital at Westmead, Westmead, NSW, Australia
- Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia
| | | | - Emily R Vasiljevski
- Orthopaedic Research & Biotechnology, The Children’s Hospital at Westmead, Westmead, NSW, Australia
- Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia
| | - Frances J Evesson
- Institute for Neuroscience and Muscle Research, The Children’s Hospital Westmead, Sydney, NSW, Australia
| | - Kathy Mikulec
- Orthopaedic Research & Biotechnology, The Children’s Hospital at Westmead, Westmead, NSW, Australia
| | - Lauren Peacock
- Orthopaedic Research & Biotechnology, The Children’s Hospital at Westmead, Westmead, NSW, Australia
| | - Kate G R Quinlan
- Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia
- Institute for Neuroscience and Muscle Research, The Children’s Hospital Westmead, Sydney, NSW, Australia
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, NSW, Australia
| | - Sandra T Cooper
- Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia
- Institute for Neuroscience and Muscle Research, The Children’s Hospital Westmead, Sydney, NSW, Australia
| | - Ute Roessner
- Metabolomics Australia, University of Melbourne, VIC, Australia
| | - David A Stevenson
- Division of Medical Genetics, Stanford University, Stanford, CA, USA
| | - David G Little
- Orthopaedic Research & Biotechnology, The Children’s Hospital at Westmead, Westmead, NSW, Australia
- Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia
| | - Aaron Schindeler
- Orthopaedic Research & Biotechnology, The Children’s Hospital at Westmead, Westmead, NSW, Australia
- Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia
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25
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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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26
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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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27
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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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28
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Takanashi M, Taira Y, Okazaki S, Takase S, Kimura T, Li CC, Xu PF, Noda A, Sakata I, Kumagai H, Ikeda Y, Iizuka Y, Yahagi N, Shimano H, Osuga JI, Ishibashi S, Kadowaki T, Okazaki H. Role of Hormone-sensitive Lipase in Leptin-Promoted Fat Loss and Glucose Lowering. J Atheroscler Thromb 2017; 24:1105-1116. [PMID: 28413180 PMCID: PMC5684476 DOI: 10.5551/jat.39552] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Aim: Myriad biological effects of leptin may lead to broad therapeutic applications for various metabolic diseases, including diabetes and its complications; however, in contrast to its anorexic effect, the molecular mechanisms underlying adipopenic and glucose-lowering effects of leptin have not been fully understood. Here we aim to clarify the role of hormone-sensitive lipase (HSL) in leptin's action. Methods: Wild-type (WT) and HSL-deficient (HSLKO) mice were made hyperleptinemic by two commonly-used methods: adenovirus-mediated overexpression of leptin and continuous subcutaneous infusion of leptin by osmotic pumps. The amount of food intake, body weights, organ weights, and parameters of glucose and lipid metabolism were measured. Results: Hyperleptinemia equally suppressed the food intake in WT and HSLKO mice. On the other hand, leptin-mediated fat loss and glucose-lowering were significantly blunted in the absence of HSL when leptin was overexpressed by recombinant adenovirus carrying leptin. By osmotic pumps, the fat-losing and glucose-lowering effects of leptin were milder due to lower levels of hyperleptinemia; although the difference between WT and HSLKO mice did not reach statistical significance, HSLKO mice had a tendency to retain more fat than WT mice in the face of hyperleptinemia. Conclusions: We clarify for the first time the role of HSL in leptin's effect using a genetic model: leptin-promoted fat loss and glucose-lowering are at least in part mediated via HSL-mediated lipolysis. Further studies to define the pathophysiological role of adipocyte lipases in leptin action may lead to a new therapeutic approach to circumvent leptin resistance.
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Affiliation(s)
- Mikio Takanashi
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Yoshino Taira
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Sachiko Okazaki
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Satoru Takase
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Takeshi Kimura
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Cheng Cheng Li
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Peng Fei Xu
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Akari Noda
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Ichiro Sakata
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University
| | - Hidetoshi Kumagai
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo
| | - Yuichi Ikeda
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo
| | - Yoko Iizuka
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Naoya Yahagi
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Hitoshi Shimano
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Jun-Ichi Osuga
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University
| | - Shun Ishibashi
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University
| | - Takashi Kadowaki
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
| | - Hiroaki Okazaki
- Departments of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo
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29
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Schweiger M, Romauch M, Schreiber R, Grabner GF, Hütter S, Kotzbeck P, Benedikt P, Eichmann TO, Yamada S, Knittelfelder O, Diwoky C, Doler C, Mayer N, De Cecco W, Breinbauer R, Zimmermann R, Zechner R. Pharmacological inhibition of adipose triglyceride lipase corrects high-fat diet-induced insulin resistance and hepatosteatosis in mice. Nat Commun 2017; 8:14859. [PMID: 28327588 PMCID: PMC5364409 DOI: 10.1038/ncomms14859] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 02/06/2017] [Indexed: 12/19/2022] Open
Abstract
Elevated circulating fatty acids (FAs) contribute to the development of obesity-associated metabolic complications such as insulin resistance (IR) and non-alcoholic fatty liver disease (NAFLD). Hence, reducing adipose tissue lipolysis to diminish the mobilization of FAs and lower their respective plasma concentrations represents a potential treatment strategy to counteract obesity-associated disorders. Here we show that specific inhibition of adipose triglyceride lipase (Atgl) with the chemical inhibitor, Atglistatin, effectively reduces adipose tissue lipolysis, weight gain, IR and NAFLD in mice fed a high-fat diet. Importantly, even long-term treatment does not lead to lipid accumulation in ectopic tissues such as the skeletal muscle or heart. Thus, the severe cardiac steatosis and cardiomyopathy that is observed in genetic models of Atgl deficiency does not occur in Atglistatin-treated mice. Our data validate the pharmacological inhibition of Atgl as a potentially powerful therapeutic strategy to treat obesity and associated metabolic disorders. The enzyme Atgl participates in the breakdown of lipids in adipose tissue. Here the authors show that pharmacological inhibition of Atgl reduces weight gain and improves metabolic health in mice fed a high-fat diet, without causing adverse effects in cardiac muscle associated with genetic depletion of Atgl.
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Affiliation(s)
- Martina Schweiger
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Matthias Romauch
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Gernot F Grabner
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Sabrina Hütter
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Petra Kotzbeck
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Pia Benedikt
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Thomas O Eichmann
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Sohsuke Yamada
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Oskar Knittelfelder
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Clemens Diwoky
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Carina Doler
- Institute of Organic Chemistry, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
| | - Nicole Mayer
- Institute of Organic Chemistry, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
| | - Werner De Cecco
- Institute of Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria
| | - Rolf Breinbauer
- Institute of Organic Chemistry, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
| | - Robert Zimmermann
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
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Biswas D, Ghosh M, Kumar S, Chakrabarti P. PPARα-ATGL pathway improves muscle mitochondrial metabolism: implication in aging. FASEB J 2016; 30:3822-3834. [PMID: 27485820 DOI: 10.1096/fj.201600571rr] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/27/2016] [Indexed: 02/05/2023]
Abstract
Adipose triglyceride lipase (ATGL) maintains an optimum mitochondrial function putatively by generating cognate ligands for peroxisome proliferator-activated receptor α (PPARα), which, together with PPARγ coactivator-1α (PGC1α), regulate muscle mitochondrial biogenesis. However, the cross-talk between ATGL and PPARα in skeletal muscle mitochondrial metabolism and its implication in chronological aging is poorly understood. The role of ATGL in muscle mitochondrial metabolism was studied by overexpressing and depleting the gene and studying its downstream effect in cultured myotubes and in murine skeletal muscle. We found that PPARα directly induces ATGL expression during myogenesis. Overexpression of ATGL significantly enhanced while depletion of ATGL attenuated mitochondrial oxidative phosphorylation and fatty acid oxidation without alteration in mitochondrial content, and it rendered PPARα and PGC1α redundant in promoting mitochondrial oxidative function. However, ATGL did not alter PPARα-dependent lipid accumulation and insulin sensitivity. In middle-aged rats, ATGL expression was higher and correlated with PPARα expression and sustained fatty acid oxidation in oxidative soleus muscle. Fenofibrate feeding further induced ATGL expression selectively in this muscle compartment. These findings illustrate that PPARα and ATGL constitute a regulatory pathway in skeletal muscle, suggesting their role as a mitochondrial metabolic reserve.-Biswas, D., Ghosh, M., Kumar, S., Chakrabarti, P. PPARα-ATGL pathway improves muscle mitochondrial metabolism: implication in aging.
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Affiliation(s)
- Dipsikha Biswas
- Division of Cell Biology and Physiology, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, India; and
| | - Mainak Ghosh
- Division of Cell Biology and Physiology, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, India; and
| | - Subhankar Kumar
- Department of Physiology, Institute of Postgraduate Medical Education and Research, Kolkata, India
| | - Partha Chakrabarti
- Division of Cell Biology and Physiology, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, India; and
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31
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El-Kafoury BM, Seif AA, El-Aziz Abd El-Hady EA, El-Sebaiee AE. Effects of transcutaneous electrical stimulation of lower limb muscles on experimental fatty liver. Arab J Gastroenterol 2016; 17:20-8. [PMID: 27067922 DOI: 10.1016/j.ajg.2016.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 10/08/2015] [Accepted: 03/09/2016] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIMS Although the beneficial effects of exercise on fatty liver have been described, a previous study conducted at our department showed that transcutaneous electrical muscle stimulation (TEMS) of lower abdominal muscles aggravated fatty liver. The present study aims to evaluate the ability of TEMS of the lower limb muscles to improve fatty liver infiltration. MATERIAL AND METHODS Thirty male Wistar rats were randomly allocated into three groups: control; fructose-fed (F), fed fructose-enriched diet for 6weeks; and fructose-fed with transcutaneous electrical muscle stimulation (F+TEMS), fed fructose-enriched diet for 6weeks and lower limb muscles subjected to TEMS during the last 3weeks of feeding, five sessions/week. Body weight, length, body mass index (BMI), and abdominal and lower limb circumferences were all recorded. Fasting blood glucose, serum insulin, serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total protein, serum albumin, high density lipoprotein cholesterol (HDL-C), triglyceride (TG), and total cholesterol (TC) levels were measured. LDL cholesterol (LDL-C) and the atherogenic index (AI) were calculated. Absolute and relative hepatic weights as well as histological examination of the liver were assessed. RESULTS Final body weight, abdominal and lower limb circumferences, absolute liver weight, homoeostasis model assessment (HOMA) score, and TG, LDL-C, AI, serum ALT, and AST levels were all significantly reduced in the (F+TEMS) group compared to the (F) group. There was a significant increase in GPx and HDL-C levels, HDL/LDL ratio, and total protein and serum albumin content in (F+TEMS) rats compared to (F) rats. Histologically, hepatic tissue from (F+TEMS) rats had minimal steatotic changes that were restricted to zone 1 and less marked inflammatory cell infiltration compared to (F) rats. CONCLUSION TEMS was able to reverse steatosis, hyperglycaemia, insulin resistance, dyslipidaemia, and fatty liver caused by fructose feeding. The study confirmed that the variation in the anatomical site of skeletal muscle contraction affects fatty liver in different ways.
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Affiliation(s)
- Bataa M El-Kafoury
- Physiology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Ansam A Seif
- Physiology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
| | | | - Ahmed E El-Sebaiee
- Physiology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt
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32
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Hypophagia and metabolic adaptations in mice with defective ATGL-mediated lipolysis cause resistance to HFD-induced obesity. Proc Natl Acad Sci U S A 2015; 112:13850-5. [PMID: 26508640 DOI: 10.1073/pnas.1516004112] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Adipose triglyceride lipase (ATGL) initiates intracellular triglyceride (TG) catabolism. In humans, ATGL deficiency causes neutral lipid storage disease with myopathy (NLSDM) characterized by a systemic TG accumulation. Mice with a genetic deletion of ATGL (AKO) also accumulate TG in many tissues. However, neither NLSDM patients nor AKO mice are exceedingly obese. This phenotype is unexpected considering the importance of the enzyme for TG catabolism in white adipose tissue (WAT). In this study, we identified the counteracting mechanisms that prevent excessive obesity in the absence of ATGL. We used "healthy" AKO mice expressing ATGL exclusively in cardiomyocytes (AKO/cTg) to circumvent the cardiomyopathy and premature lethality observed in AKO mice. AKO/cTg mice were protected from high-fat diet (HFD)-induced obesity despite complete ATGL deficiency in WAT and normal adipocyte differentiation. AKO/cTg mice were highly insulin sensitive under hyperinsulinemic-euglycemic clamp conditions, eliminating insulin insensitivity as a possible protective mechanism. Instead, reduced food intake and altered signaling by peroxisome proliferator-activated receptor-gamma (PPAR-γ) and sterol regulatory element binding protein-1c in WAT accounted for the phenotype. These adaptations led to reduced lipid synthesis and storage in WAT of HFD-fed AKO/cTg mice. Treatment with the PPAR-γ agonist rosiglitazone reversed the phenotype. These results argue for the existence of an adaptive interdependence between lipolysis and lipid synthesis. Pharmacological inhibition of ATGL may prove useful to prevent HFD-induced obesity and insulin resistance.
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33
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Foryst-Ludwig A, Kreissl MC, Benz V, Brix S, Smeir E, Ban Z, Januszewicz E, Salatzki J, Grune J, Schwanstecher AK, Blumrich A, Schirbel A, Klopfleisch R, Rothe M, Blume K, Halle M, Wolfarth B, Kershaw EE, Kintscher U. Adipose Tissue Lipolysis Promotes Exercise-induced Cardiac Hypertrophy Involving the Lipokine C16:1n7-Palmitoleate. J Biol Chem 2015; 290:23603-15. [PMID: 26260790 DOI: 10.1074/jbc.m115.645341] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Indexed: 12/28/2022] Open
Abstract
Endurance exercise training induces substantial adaptive cardiac modifications such as left ventricular hypertrophy (LVH). Simultaneously to the development of LVH, adipose tissue (AT) lipolysis becomes elevated upon endurance training to cope with enhanced energy demands. In this study, we investigated the impact of adipose tissue lipolysis on the development of exercise-induced cardiac hypertrophy. Mice deficient for adipose triglyceride lipase (Atgl) in AT (atATGL-KO) were challenged with chronic treadmill running. Exercise-induced AT lipolytic activity was significantly reduced in atATGL-KO mice accompanied by the absence of a plasma fatty acid (FA) increase. These processes were directly associated with a prominent attenuation of myocardial FA uptake in atATGL-KO and a significant reduction of the cardiac hypertrophic response to exercise. FA serum profiling revealed palmitoleic acid (C16:1n7) as a new molecular co-mediator of exercise-induced cardiac hypertrophy by inducing nonproliferative cardiomyocyte growth. In parallel, serum FA analysis and echocardiography were performed in 25 endurance athletes. In consonance, the serum C16:1n7 palmitoleate level exhibited a significantly positive correlation with diastolic interventricular septum thickness in those athletes. No correlation existed between linoleic acid (18:2n6) and diastolic interventricular septum thickness. Collectively, our data provide the first evidence that adipose tissue lipolysis directly promotes the development of exercise-induced cardiac hypertrophy involving the lipokine C16:1n7 palmitoleate as a molecular co-mediator. The identification of a lipokine involved in physiological cardiac growth may help to develop future lipid-based therapies for pathological LVH or heart failure.
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Affiliation(s)
- Anna Foryst-Ludwig
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany, the DZHK (German Center for Cardiovascular Research), 10115 Berlin, Germany
| | - Michael C Kreissl
- the Department of Nuclear Medicine, University Hospital Wuerzburg, 97080 Wuerzburg, Germany
| | - Verena Benz
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Sarah Brix
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Elia Smeir
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Zsofia Ban
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Elżbieta Januszewicz
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Janek Salatzki
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Jana Grune
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Anne-Kathrin Schwanstecher
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Annelie Blumrich
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Andreas Schirbel
- the Department of Nuclear Medicine, University Hospital Wuerzburg, 97080 Wuerzburg, Germany
| | - Robert Klopfleisch
- the Department of Veterinary Pathology, College of Veterinary Medicine, Freie Universität Berlin, 14163 Berlin, Germany
| | | | - Katharina Blume
- the Department of Prevention, Rehabilitation, and Sports Medicine, Technische Universitaet Muenchen, 80809 Muenchen, Germany
| | - Martin Halle
- the Department of Prevention, Rehabilitation, and Sports Medicine, Technische Universitaet Muenchen, 80809 Muenchen, Germany, the DZHK (German Center for Cardiovascular Research), Munich Heart Alliance, 80809 Munich, Germany
| | - Bernd Wolfarth
- the Department of Sports Medicine, Humboldt University/Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany
| | - Erin E Kershaw
- the Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, and
| | - Ulrich Kintscher
- From the Institute of Pharmacology, Center for Cardiovascular Research, Charité-Universitaetsmedizin Berlin, 10115 Berlin, Germany, the DZHK (German Center for Cardiovascular Research), 10115 Berlin, Germany
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Cooper DE, Young PA, Klett EL, Coleman RA. Physiological Consequences of Compartmentalized Acyl-CoA Metabolism. J Biol Chem 2015; 290:20023-31. [PMID: 26124277 DOI: 10.1074/jbc.r115.663260] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Meeting the complex physiological demands of mammalian life requires strict control of the metabolism of long-chain fatty acyl-CoAs because of the multiplicity of their cellular functions. Acyl-CoAs are substrates for energy production; stored within lipid droplets as triacylglycerol, cholesterol esters, and retinol esters; esterified to form membrane phospholipids; or used to activate transcriptional and signaling pathways. Indirect evidence suggests that acyl-CoAs do not wander freely within cells, but instead, are channeled into specific pathways. In this review, we will discuss the evidence for acyl-CoA compartmentalization, highlight the key modes of acyl-CoA regulation, and diagram potential mechanisms for controlling acyl-CoA partitioning.
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Affiliation(s)
| | | | - Eric L Klett
- From the Departments of Nutrition and Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
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Dubé JJ, Sitnick MT, Schoiswohl G, Wills RC, Basantani MK, Cai L, Pulinilkunnil T, Kershaw EE. Adipose triglyceride lipase deletion from adipocytes, but not skeletal myocytes, impairs acute exercise performance in mice. Am J Physiol Endocrinol Metab 2015; 308:E879-90. [PMID: 25783895 PMCID: PMC4436997 DOI: 10.1152/ajpendo.00530.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 03/09/2015] [Indexed: 12/22/2022]
Abstract
Adipose triglyceride lipase (ATGL) is the rate-limiting enzyme mediating triacylglycerol hydrolysis in virtually all cells, including adipocytes and skeletal myocytes, and hence, plays a critical role in mobilizing fatty acids. Global ATGL deficiency promotes skeletal myopathy and exercise intolerance in mice and humans, and yet the tissue-specific contributions to these phenotypes remain unknown. The goal of this study was to determine the relative contribution of ATGL-mediated triacylglycerol hydrolysis in adipocytes vs. skeletal myocytes to acute exercise performance. To achieve this goal, we generated murine models with adipocyte- and skeletal myocyte-specific targeted deletion of ATGL. We then subjected untrained mice to acute peak and submaximal exercise interventions and assessed exercise performance and energy substrate metabolism. Impaired ATGL-mediated lipolysis within adipocytes reduced peak and submaximal exercise performance, reduced peripheral energy substrate availability, shifted energy substrate preference toward carbohydrate oxidation, and decreased HSL Ser(660) phosphorylation and mitochondrial respiration within skeletal muscle. In contrast, impaired ATGL-mediated lipolysis within skeletal myocytes was not sufficient to reduce peak and submaximal exercise performance or peripheral energy substrate availability and instead tended to enhance metabolic flexibility during peak exercise. Furthermore, the expanded intramyocellular triacylglycerol pool in these mice was reduced following exercise in association with preserved HSL phosphorylation, suggesting that HSL may compensate for impaired ATGL action in skeletal muscle during exercise. These data suggest that adipocyte rather than skeletal myocyte ATGL-mediated lipolysis plays a greater role during acute exercise in part because of compensatory mechanisms that maintain lipolysis in muscle, but not adipose tissue, when ATGL is absent.
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Affiliation(s)
- John J Dubé
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Mitch T Sitnick
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Gabriele Schoiswohl
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Rachel C Wills
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Mahesh K Basantani
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Lingzhi Cai
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Thomas Pulinilkunnil
- Department of Biochemistry and Molecular Biology, Dalhousie Medicine New Brunswick, Dalhousie University, Saint John, New Brunswick, Canada
| | - Erin E Kershaw
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; and
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36
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Coelho M, Nunes P, Mendes VM, Manadas B, Heerschap A, Jones JG. Effect of Global ATGL Knockout on Murine Fasting Glucose Kinetics. J Diabetes Res 2015; 2015:542029. [PMID: 26236747 PMCID: PMC4506825 DOI: 10.1155/2015/542029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 06/08/2015] [Indexed: 12/25/2022] Open
Abstract
Mice deficient in adipose triglyceride lipase (ATGL(-/-)) present elevated ectopic lipid levels but are paradoxically glucose-tolerant. Measurement of endogenous glucose production (EGP) and Cori cycle activity provide insights into the maintenance of glycemic control in these animals. These parameters were determined in 7 wild-type (ATGL(+/-)) and 6 ATGL(-/-) mice by a primed-infusion of [U-(13)C6]glucose followed by LC-MS/MS targeted mass-isotopomer analysis of blood glucose. EGP was quantified by isotope dilution of [U-(13)C6]glucose while Cori cycling was estimated by analysis of glucose triose (13)C-isotopomers. Fasting plasma free fatty-acids were significantly lower in ATGL(-/-) versus control mice (0.43 ± 0.05 mM versus 0.73 ± 0.11 mM, P < 0.05). Six-hour fasting EGP rates were identical for both ATGL(-/-) and control mice (79 ± 11 versus 71 ± 7 μmol/kg/min, resp.). Peripheral glucose metabolism was dominated by Cori cycling (80 ± 2% and 82 ± 7% of glucose disposal for ATGL(-/-) and control mice, resp.) indicating that peripheral glucose oxidation was not significantly upregulated in ATGL(-/-) mice under these conditions. The glucose (13)C-isotopomer distributions in both ATGL(-/-) and control mice were consistent with extensive hepatic pyruvate recycling. This suggests that gluconeogenic outflow from the Krebs cycle was also well compensated in ATGL(-/-) mice.
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Affiliation(s)
- Margarida Coelho
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | | | - Vera M. Mendes
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Bruno Manadas
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Arend Heerschap
- Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands
| | - John G. Jones
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Portuguese Diabetes Association (APDP), Lisbon, Portugal
- *John G. Jones:
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Ogasawara J, Izawa T, Sakurai T, Sakurai T, Shirato K, Ishibashi Y, Ishida H, Ohno H, Kizaki T. The Molecular Mechanism Underlying Continuous Exercise Training-Induced Adaptive Changes of Lipolysis in White Adipose Cells. J Obes 2015; 2015:473430. [PMID: 26075089 PMCID: PMC4444571 DOI: 10.1155/2015/473430] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 04/04/2015] [Accepted: 04/27/2015] [Indexed: 01/04/2023] Open
Abstract
Physical exercise accelerates the mobilization of free fatty acids from white adipocytes to provide fuel for energy. This happens in several tissues and helps to regulate a whole-body state of metabolism. Under these conditions, the hydrolysis of triacylglycerol (TG) that is found in white adipocytes is known to be augmented via the activation of these lipolytic events, which is referred to as the "lipolytic cascade." Indeed, evidence has shown that the lipolytic responses in white adipocytes are upregulated by continuous exercise training (ET) through the adaptive changes in molecules that constitute the lipolytic cascade. During the past few decades, many lipolysis-related molecules have been identified. Of note, the discovery of a new lipase, known as adipose triglyceride lipase, has redefined the existing concepts of the hormone-sensitive lipase-dependent hydrolysis of TG in white adipocytes. This review outlines the alterations in the lipolytic molecules of white adipocytes that result from ET, which includes the molecular regulation of TG lipases through the lipolytic cascade.
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Affiliation(s)
- Junetsu Ogasawara
- Department of Molecular Predictive Medicine and Sport Science, Kyorin University, School of Medicine, Mitaka, Tokyo 181-8611, Japan
- *Junetsu Ogasawara:
| | - Tetsuya Izawa
- Graduate School of Health and Sports Science, Doshisha University, Kyotanabe, Kyoto 610-0394, Japan
| | - Tomonobu Sakurai
- Faculty of Culture and Sport Policy, Toin University of Yokohama, Yokohama, Kanagawa 225-8503, Japan
| | - Takuya Sakurai
- Department of Molecular Predictive Medicine and Sport Science, Kyorin University, School of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Ken Shirato
- Department of Molecular Predictive Medicine and Sport Science, Kyorin University, School of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Yoshinaga Ishibashi
- Department of Molecular Predictive Medicine and Sport Science, Kyorin University, School of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Hitoshi Ishida
- Department of Third Internal Medicine, Kyorin University, School of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Hideki Ohno
- Department of Molecular Predictive Medicine and Sport Science, Kyorin University, School of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Takako Kizaki
- Department of Molecular Predictive Medicine and Sport Science, Kyorin University, School of Medicine, Mitaka, Tokyo 181-8611, Japan
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Choi SS, Kim ES, Koh M, Lee SJ, Lim D, Yang YR, Jang HJ, Seo KA, Min SH, Lee IH, Park SB, Suh PG, Choi JH. A novel non-agonist peroxisome proliferator-activated receptor γ (PPARγ) ligand UHC1 blocks PPARγ phosphorylation by cyclin-dependent kinase 5 (CDK5) and improves insulin sensitivity. J Biol Chem 2014; 289:26618-26629. [PMID: 25100724 DOI: 10.1074/jbc.m114.566794] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thiazolidinedione class of anti-diabetic drugs which are known as peroxisome proliferator-activated receptor γ (PPARγ) ligands have been used to treat metabolic disorders, but thiazolidinediones can also cause several severe side effects, including congestive heart failure, fluid retention, and weight gain. In this study, we describe a novel synthetic PPARγ ligand UNIST HYUNDAI Compound 1 (UHC1) that binds tightly to PPARγ without the classical agonism and which blocks cyclin-dependent kinase 5 (CDK5)-mediated PPARγ phosphorylation. We modified the non-agonist PPARγ ligand SR1664 chemically to improve its solubility and then developed a novel PPARγ ligand, UHC1. According to our docking simulation, UHC1 occupied the ligand-binding site of PPARγ with a higher docking score than SR1664. In addition, UHC1 more potently blocked CDK5-mediated PPARγ phosphorylation at Ser-273. Surprisingly, UHC1 treatment effectively ameliorated the inflammatory response both in vitro and in high-fat diet-fed mice. Furthermore, UHC1 treatment dramatically improved insulin sensitivity in high-fat diet-fed mice without causing fluid retention and weight gain. Taken together, compared with SR1664, UHC1 exhibited greater beneficial effects on glucose and lipid metabolism by blocking CDK5-mediated PPARγ phosphorylation, and these data indicate that UHC1 could be a novel therapeutic agent for use in type 2 diabetes and related metabolic disorders.
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Affiliation(s)
- Sun-Sil Choi
- Department of Biological Science, Ulsan National Institute of Science and Technology, Ulsan 689-798, Korea
| | - Eun Sun Kim
- Department of Biological Science, Ulsan National Institute of Science and Technology, Ulsan 689-798, Korea
| | - Minseob Koh
- Department of Chemistry, Seoul National University, Seoul 151-747, Korea
| | - Soo-Jin Lee
- Department of Biological Science, Ulsan National Institute of Science and Technology, Ulsan 689-798, Korea
| | - Donghyun Lim
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, 80 Cheombok-ro, Dong-gu, Daegu 701-310, Korea
| | - Yong Ryoul Yang
- Department of Biological Science, Ulsan National Institute of Science and Technology, Ulsan 689-798, Korea
| | - Hyun-Jun Jang
- Department of Biological Science, Ulsan National Institute of Science and Technology, Ulsan 689-798, Korea
| | - Kyung-Ah Seo
- Department of Biophysics and Chemical Biology/Bio-MAX Institute, Seoul National University, Seoul 151-747, Korea, and
| | - Sang-Hyun Min
- Department of Biophysics and Chemical Biology/Bio-MAX Institute, Seoul National University, Seoul 151-747, Korea, and
| | - In Hee Lee
- Department of Medical Chemistry, Hyundai Pharm Co., Ltd., Suwon, Gyonggi 443-270, Korea
| | - Seung Bum Park
- Department of Chemistry, Seoul National University, Seoul 151-747, Korea,; New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, 80 Cheombok-ro, Dong-gu, Daegu 701-310, Korea
| | - Pann-Ghill Suh
- Department of Biological Science, Ulsan National Institute of Science and Technology, Ulsan 689-798, Korea
| | - Jang Hyun Choi
- Department of Biological Science, Ulsan National Institute of Science and Technology, Ulsan 689-798, Korea,.
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Fujitani M, Matsumura S, Masuda D, Yamashita S, Fushiki T, Inoue K. CD36, but not GPR120, is required for efficient fatty acid utilization during endurance exercise. Biosci Biotechnol Biochem 2014; 78:1871-8. [PMID: 25070011 DOI: 10.1080/09168451.2014.940835] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Fatty acids (FA) are an important energy source during exercise. In addition to its role as an energy supply for skeletal muscle, FA may activate signaling pathways that regulate gene expression. FA translocase/cluster of differentiation 36 (CD36) and G protein-coupled receptor GPR120 are long-chain FA receptors. In this study, we investigated the impact of CD36 or GPR120 deletion on energy metabolism during exercise. CD36 has been reported to facilitate cellular transport and oxidation of FA during endurance exercise. We show that CD36 deletion decreased exogenous FA oxidation during exercise, using a combination of (13)C-labeled FA oxidation measurement and indirect calorimetry. In contrast, GPR120 deletion had no observable effect on energy metabolism during exercise. Our results further substantiate that CD36-mediated FA transport plays an essential role in efficient FA oxidation during exercise.
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Affiliation(s)
- Mina Fujitani
- a Laboratory of Nutrition Chemistry, Graduate School of Agriculture , Kyoto University , Sakyou-ku , Japan
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40
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Nielsen TS, Jessen N, Jørgensen JOL, Møller N, Lund S. Dissecting adipose tissue lipolysis: molecular regulation and implications for metabolic disease. J Mol Endocrinol 2014; 52:R199-222. [PMID: 24577718 DOI: 10.1530/jme-13-0277] [Citation(s) in RCA: 263] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Lipolysis is the process by which triglycerides (TGs) are hydrolyzed to free fatty acids (FFAs) and glycerol. In adipocytes, this is achieved by sequential action of adipose TG lipase (ATGL), hormone-sensitive lipase (HSL), and monoglyceride lipase. The activity in the lipolytic pathway is tightly regulated by hormonal and nutritional factors. Under conditions of negative energy balance such as fasting and exercise, stimulation of lipolysis results in a profound increase in FFA release from adipose tissue (AT). This response is crucial in order to provide the organism with a sufficient supply of substrate for oxidative metabolism. However, failure to efficiently suppress lipolysis when FFA demands are low can have serious metabolic consequences and is believed to be a key mechanism in the development of type 2 diabetes in obesity. As the discovery of ATGL in 2004, substantial progress has been made in the delineation of the remarkable complexity of the regulatory network controlling adipocyte lipolysis. Notably, regulatory mechanisms have been identified on multiple levels of the lipolytic pathway, including gene transcription and translation, post-translational modifications, intracellular localization, protein-protein interactions, and protein stability/degradation. Here, we provide an overview of the recent advances in the field of AT lipolysis with particular focus on the molecular regulation of the two main lipases, ATGL and HSL, and the intracellular and extracellular signals affecting their activity.
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Affiliation(s)
- Thomas Svava Nielsen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, DenmarkThe Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Niels Jessen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, DenmarkThe Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Jens Otto L Jørgensen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Niels Møller
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Sten Lund
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
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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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42
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Tan JSY, Seow CJP, Goh VJ, Silver DL. Recent advances in understanding proteins involved in lipid droplet formation, growth and fusion. J Genet Genomics 2014; 41:251-9. [PMID: 24894352 DOI: 10.1016/j.jgg.2014.03.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 03/03/2014] [Accepted: 03/05/2014] [Indexed: 01/29/2023]
Abstract
Lipid droplets (LDs) were once viewed as simple, inert lipid micelles. However, they are now known to be organelles with a rich proteome involved in a myriad of cellular processes. LDs are heterogeneous in nature with different sizes and compositions of phospholipids, neutral lipids and proteins. This review takes a focused look at the roles of proteins involved in the regulation of LD formation, expansion, and morphology. The related proteins are summarized such as the fat-specific protein (Fsp27), fat storage-inducing transmembrane (FIT) proteins, seipin and ADP-ribosylation factor 1-coat protein complex I (Arf-COPI). Finally, we present important challenges in LD biology for a deeper understanding of this dynamic organelle to be achieved.
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Affiliation(s)
- Jolene S Y Tan
- Signature Research Program in Cardiovascular & Metabolic Disorders, Duke-NUS Graduate Medical School Singapore, Singapore 169857, Singapore
| | - Colin J P Seow
- Signature Research Program in Cardiovascular & Metabolic Disorders, Duke-NUS Graduate Medical School Singapore, Singapore 169857, Singapore
| | - Vera J Goh
- Signature Research Program in Cardiovascular & Metabolic Disorders, Duke-NUS Graduate Medical School Singapore, Singapore 169857, Singapore
| | - David L Silver
- Signature Research Program in Cardiovascular & Metabolic Disorders, Duke-NUS Graduate Medical School Singapore, Singapore 169857, Singapore.
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43
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Nagy HM, Paar M, Heier C, Moustafa T, Hofer P, Haemmerle G, Lass A, Zechner R, Oberer M, Zimmermann R. Adipose triglyceride lipase activity is inhibited by long-chain acyl-coenzyme A. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:588-94. [PMID: 24440819 PMCID: PMC3988850 DOI: 10.1016/j.bbalip.2014.01.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 12/20/2013] [Accepted: 01/06/2014] [Indexed: 12/28/2022]
Abstract
Adipose triglyceride lipase (ATGL) is required for efficient mobilization of triglyceride (TG) stores in adipose tissue and non-adipose tissues. Therefore, ATGL strongly determines the availability of fatty acids for metabolic reactions. ATGL activity is regulated by a complex network of lipolytic and anti-lipolytic hormones. These signals control enzyme expression and the interaction of ATGL with the regulatory proteins CGI-58 and G0S2. Up to date, it was unknown whether ATGL activity is also controlled by lipid intermediates generated during lipolysis. Here we show that ATGL activity is inhibited by long-chain acyl-CoAs in a non-competitive manner, similar as previously shown for hormone-sensitive lipase (HSL), the rate-limiting enzyme for diglyceride breakdown in adipose tissue. ATGL activity is only marginally inhibited by medium-chain acyl-CoAs, diglycerides, monoglycerides, and free fatty acids. Immunoprecipitation assays revealed that acyl-CoAs do not disrupt the protein–protein interaction of ATGL and its co-activator CGI-58. Furthermore, inhibition of ATGL is independent of the presence of CGI-58 and occurs directly at the N-terminal patatin-like phospholipase domain of the enzyme. In conclusion, our results suggest that inhibition of the major lipolytic enzymes ATGL and HSL by long-chain acyl-CoAs could represent an effective feedback mechanism controlling lipolysis and protecting cells from lipotoxic concentrations of fatty acids and fatty acid-derived lipid metabolites. Long-chain acyl-CoAs inhibit ATGL in a non-competitive manner. Inhibition occurs at the N-terminal region of ATGL and independent of CGI-58, the co-activator of ATGL. Acyl-CoA mediated inhibition of lipolysis could represent a general feedback mechanism protecting cells from fatty acid overload.
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Affiliation(s)
- Harald M Nagy
- Institute of Molecular Biosciences, University of Graz, Austria
| | - Margret Paar
- Institute of Molecular Biosciences, University of Graz, Austria
| | - Christoph Heier
- Institute of Molecular Biosciences, University of Graz, Austria
| | - Tarek Moustafa
- Institute of Molecular Biosciences, University of Graz, Austria
| | - Peter Hofer
- Institute of Molecular Biosciences, University of Graz, Austria
| | | | - Achim Lass
- Institute of Molecular Biosciences, University of Graz, Austria
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Austria
| | - Monika Oberer
- Institute of Molecular Biosciences, University of Graz, Austria
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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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45
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Badin PM, Langin D, Moro C. Dynamics of skeletal muscle lipid pools. Trends Endocrinol Metab 2013; 24:607-15. [PMID: 23988586 DOI: 10.1016/j.tem.2013.08.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 07/22/2013] [Accepted: 08/03/2013] [Indexed: 11/20/2022]
Abstract
Intramyocellular triacylglycerol (IMTG) is emerging as an important energy fuel source during muscle contraction and are adaptively increased in response to exercise, without adverse physiological effects. Paradoxically, elevated IMTG content in obese and type 2 diabetics has been linked to insulin resistance, highlighting the importance of IMTG pools in physiology and pathology. Two separate views suggest that IMTG dynamics are determinant for skeletal muscle fat oxidation, and that disruption of IMTG dynamics facilitates the accumulation of lipotoxic intermediates such as diacylglycerols and ceramides that interfere with insulin signaling. Thus, understanding the factors that control IMTG dynamics is crucial. Here we discuss recent literature describing the regulation of IMTG pools with a particular emphasis on lipases and lipid droplet (LD)-associated proteins.
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Affiliation(s)
- Pierre-Marie Badin
- Obesity Research Laboratory, Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche (UMR) 1048, Institute of Metabolic and Cardiovascular Diseases (I2MC), Toulouse, France; University of Toulouse, UMR1048, Paul Sabatier University, Toulouse, France
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46
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Sitnick MT, Basantani MK, Cai L, Schoiswohl G, Yazbeck CF, Distefano G, Ritov V, DeLany JP, Schreiber R, Stolz DB, Gardner NP, Kienesberger PC, Pulinilkunnil T, Zechner R, Goodpaster BH, Coen P, Kershaw EE. Skeletal muscle triacylglycerol hydrolysis does not influence metabolic complications of obesity. Diabetes 2013; 62:3350-61. [PMID: 23835334 PMCID: PMC3781480 DOI: 10.2337/db13-0500] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Intramyocellular triacylglycerol (IMTG) accumulation is highly associated with insulin resistance and metabolic complications of obesity (lipotoxicity), whereas comparable IMTG accumulation in endurance-trained athletes is associated with insulin sensitivity (the athlete's paradox). Despite these findings, it remains unclear whether changes in IMTG accumulation and metabolism per se influence muscle-specific and systemic metabolic homeostasis and insulin responsiveness. By mediating the rate-limiting step in triacylglycerol hydrolysis, adipose triglyceride lipase (ATGL) has been proposed to influence the storage/production of deleterious as well as essential lipid metabolites. However, the physiological relevance of ATGL-mediated triacylglycerol hydrolysis in skeletal muscle remains unknown. To determine the contribution of IMTG hydrolysis to tissue-specific and systemic metabolic phenotypes in the context of obesity, we generated mice with targeted deletion or transgenic overexpression of ATGL exclusively in skeletal muscle. Despite dramatic changes in IMTG content on both chow and high-fat diets, modulation of ATGL-mediated IMTG hydrolysis did not significantly influence systemic energy, lipid, or glucose homeostasis, nor did it influence insulin responsiveness or mitochondrial function. These data argue against a role for altered IMTG accumulation and lipolysis in muscle insulin resistance and metabolic complications of obesity.
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Affiliation(s)
- Mitch T. Sitnick
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Mahesh K. Basantani
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Lingzhi Cai
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Gabriele Schoiswohl
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Cynthia F. Yazbeck
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Giovanna Distefano
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Vladimir Ritov
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - James P. DeLany
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Donna B. Stolz
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Noah P. Gardner
- Novartis Institute of Biomedical Research, Cambridge, Massachusetts
| | - Petra C. Kienesberger
- Department of Biochemistry and Molecular Biology, Dalhousie University, Dalhousie Medicine New Brunswick, Saint John, New Brunswick, Canada
| | - Thomas Pulinilkunnil
- Department of Biochemistry and Molecular Biology, Dalhousie University, Dalhousie Medicine New Brunswick, Saint John, New Brunswick, Canada
| | - Rudolf Zechner
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Bret H. Goodpaster
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Paul Coen
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Health and Physical Activity, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Erin E. Kershaw
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
- Corresponding author: Erin E. Kershaw,
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Alsted TJ, Ploug T, Prats C, Serup AK, Høeg L, Schjerling P, Holm C, Zimmermann R, Fledelius C, Galbo H, Kiens B. Contraction-induced lipolysis is not impaired by inhibition of hormone-sensitive lipase in skeletal muscle. J Physiol 2013; 591:5141-55. [PMID: 23878361 DOI: 10.1113/jphysiol.2013.260794] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In skeletal muscle hormone-sensitive lipase (HSL) has long been accepted to be the principal enzyme responsible for lipolysis of intramyocellular triacylglycerol (IMTG) during contractions. However, this notion is based on in vitro lipase activity data, which may not reflect the in vivo lipolytic activity. We investigated lipolysis of IMTG in soleus muscles electrically stimulated to contract ex vivo during acute pharmacological inhibition of HSL in rat muscles and in muscles from HSL knockout (HSL-KO) mice. Measurements of IMTG are complicated by the presence of adipocytes located between the muscle fibres. To circumvent the problem with this contamination we analysed intramyocellular lipid droplet content histochemically. At maximal inhibition of HSL in rat muscles, contraction-induced breakdown of IMTG was identical to that seen in control muscles (P < 0.001). In response to contractions IMTG staining decreased significantly in both HSL-KO and WT muscles (P < 0.05). In vitro TG hydrolase activity data revealed that adipose triglyceride lipase (ATGL) and HSL collectively account for ∼98% of the TG hydrolase activity in mouse skeletal muscle, other TG lipases accordingly being of negligible importance for lipolysis of IMTG. The present study is the first to demonstrate that contraction-induced lipolysis of IMTG occurs in the absence of HSL activity in rat and mouse skeletal muscle. Furthermore, the results suggest that ATGL is activated and plays a major role in lipolysis of IMTG during muscle contractions.
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Affiliation(s)
- Thomas J Alsted
- B. Kiens: Section of Molecular Physiology, Department of Nutrition, Exercise and Sport, University of Copenhagen, Universitetsparken 13, DK, 2100 Copenhagen, Denmark.
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48
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Schrammel A, Mussbacher M, Winkler S, Haemmerle G, Stessel H, Wölkart G, Zechner R, Mayer B. Cardiac oxidative stress in a mouse model of neutral lipid storage disease. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1600-8. [PMID: 23867907 PMCID: PMC3795454 DOI: 10.1016/j.bbalip.2013.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/19/2013] [Accepted: 07/08/2013] [Indexed: 12/11/2022]
Abstract
Cardiac oxidative stress has been implicated in the pathogenesis of hypertrophy, cardiomyopathy and heart failure. Systemic deletion of the gene encoding adipose triglyceride lipase (ATGL), the enzyme that catalyzes the rate-limiting step of triglyceride lipolysis, results in a phenotype characterized by severe steatotic cardiac dysfunction. The objective of the present study was to investigate a potential role of oxidative stress in cardiac ATGL deficiency. Hearts of mice with global ATGL knockout were compared to those of mice with cardiomyocyte-restricted overexpression of ATGL and to those of wildtype littermates. Our results demonstrate that oxidative stress, measured as lucigenin chemiluminescence, was increased ~ 6-fold in ATGL-deficient hearts. In parallel, cytosolic NADPH oxidase subunits p67phox and p47phox were upregulated 4–5-fold at the protein level. Moreover, a prominent upregulation of different inflammatory markers (tumor necrosis factor α, monocyte chemotactant protein-1, interleukin 6, and galectin-3) was observed in those hearts. Both the oxidative and inflammatory responses were abolished upon cardiomyocyte-restricted overexpression of ATGL. Investigating the effect of oxidative and inflammatory stress on nitric oxide/cGMP signal transduction we observed a ~ 2.5-fold upregulation of soluble guanylate cyclase activity and a ~ 2-fold increase in cardiac tetrahydrobiopterin levels. Systemic treatment of ATGL-deficient mice with the superoxide dismutase mimetic Mn(III)tetrakis (4-benzoic acid) porphyrin did not ameliorate but rather aggravated cardiac oxidative stress. Our data suggest that oxidative and inflammatory stress seems involved in lipotoxic heart disease. Upregulation of soluble guanylate cyclase and cardiac tetrahydrobiopterin might be regarded as counterregulatory mechanisms in cardiac ATGL deficiency. ATGL(−/−) mice suffer from severe cardiac oxidative stress originating from upregulation of NOX2-dependent NADPH oxidase. Inflammation markers TNFα, MCP-1, IL-6, and Mac-2 are increased in cardiac ATGL deficiency. Activity of sGC and cardiac BH4 levels are elevated in ATGL(−/−) hearts. Systemic treatment of ATGL(−/−) mice with the SOD mimetic MnTBAP did not ameliorate oxidative stress.
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Key Words
- (s)GC
- (soluble) guanylate cyclase
- 2,2-diethyl-1-nitroso-oxyhydrazine
- ATGL
- ATGL(−/−)
- Adipose triglyceride lipase
- BH(2)
- BH(4)
- Cardiac hypertrophy
- DAG
- DEA/NO
- FFA
- GAPDH
- IL-6
- Inflammation
- MCP-1
- Mac-2
- Mn(III)tetrakis (4-benzoic acid) porphyrin chloride
- MnTBAP
- NADPH
- NADPH oxidase
- NO
- NOX
- ONOO(−)
- Oxidative stress
- PBS
- PKC
- PPARα
- SOD
- TG
- TNFα
- VASP
- adipose triglyceride lipase
- adipose triglyceride lipase knockout
- diacylglycerol
- dihydrobiopterin, [2-amino-6-(1,2-dihydroxypropyl)-7,8-dihydro-1H-pteridin-4-one]
- eNOS
- endothelial nitric oxide synthase
- free fatty acid
- galectin-3
- glyceraldehyde-3-phosphate dehydrogenase
- iNOS
- inducible nitric oxide synthase
- interleukin 6
- monocyte chemotactic protein-1
- nNOS
- neuronal nitric oxide synthase
- nicotinamide adenine dinucleotide phosphate
- nitric oxide
- pVASP
- peroxisome proliferator receptor α
- peroxynitrite
- phosphate-buffered saline
- phosphorylated vasodilator-stimulated phosphoprotein
- protein kinase C
- superoxide dismutase
- tetrahydrobiopterin, [(6R)-2-amino-6-[(1R,2S)-1,2-dihydroxypropyl]-5,6,7,8-tetrahydropteridin-4(1H)-one]
- triacylglycerol
- tumor necrosis factor α
- vasodilator-stimulated phosphoprotein
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Affiliation(s)
- Astrid Schrammel
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
- Corresponding author. Tel.: + 43 316 380 5559; fax: + 43 316 380 9890.
| | - Marion Mussbacher
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Sarah Winkler
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Guenter Haemmerle
- Department of Molecular Biosciences, University of Graz, Heinrichstraße 31, 8010 Graz, Austria
| | - Heike Stessel
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Gerald Wölkart
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Rudolf Zechner
- Department of Molecular Biosciences, University of Graz, Heinrichstraße 31, 8010 Graz, Austria
| | - Bernd Mayer
- Department of Pharmacology and Toxicology, Institute of Pharmaceutical Sciences, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
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49
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Dobrzyn P, Pyrkowska A, Duda MK, Bednarski T, Maczewski M, Langfort J, Dobrzyn A. Expression of lipogenic genes is upregulated in the heart with exercise training-induced but not pressure overload-induced left ventricular hypertrophy. Am J Physiol Endocrinol Metab 2013; 304:E1348-58. [PMID: 23632628 DOI: 10.1152/ajpendo.00603.2012] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac hypertrophy is accompanied by molecular remodeling that affects different cellular pathways, including fatty acid (FA) utilization. In the present study, we show that cardiac lipid metabolism is differentially regulated in response to physiological (endurance training) and pathological [abdominal aortic banding (AAB)] hypertrophic stimuli. Physiological hypertrophy was accompanied by an increased expression of lipogenic genes and the activation of sterol regulatory element-binding protein-1c and Akt signaling. Additionally, FA oxidation pathways regulated by AMP-activated protein kinase (AMPK) and peroxisome proliferator activated receptor-α (PPARα) were induced in trained hearts. Cardiac lipid content was not changed by physiological stimulation, underlining balanced lipid utilization in the trained heart. Moreover, pathological hypertrophy induced the AMPK-regulated oxidative pathway, whereas PPARα and expression of its downstream targets, i.e., acyl-CoA oxidase and carnitine palmitoyltransferase I, were not affected by AAB. In contrast, pathological hypertrophy leads to cardiac triglyceride (TG) and diacylglycerol (DAG) accumulation, although the expression of lipogenic genes and the levels of FA transport proteins (CD36 and FATP) were not changed or reduced compared with the sham group. A possible explanation for this phenomenon is a decrease in lipolysis, as evidenced by the increased content of adipose triglyceride lipase inhibitor G0S2, the increased phosphorylation of hormone-sensitive lipase at Ser(565), and the decreased protein levels of DAG lipase that attenuate TG and DAG contents. The increased TG and DAG accumulation observed in AAB-induced hypertrophy might have lipotoxic effects, thereby predisposing to cardiomyopathy and heart failure in the future.
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Affiliation(s)
- Pawel Dobrzyn
- Laboratory of Molecular and Medical Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
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50
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Xu C, Bai B, Fan P, Cai Y, Huang B, Law IKM, Liu L, Xu A, Tung C, Li X, Siu FM, Che CM, Vanhoutte PM, Wang Y. Selective overexpression of human SIRT1 in adipose tissue enhances energy homeostasis and prevents the deterioration of insulin sensitivity with ageing in mice. Am J Transl Res 2013; 5:412-426. [PMID: 23724165 PMCID: PMC3665915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 05/21/2013] [Indexed: 06/02/2023]
Abstract
SIRT1, a longevity regulator and NAD(+)-dependent deacetylase, plays a critical role in promoting metabolic fitness associated with calorie restriction and healthy ageing. Using a tissue-specific transgenic approach, the present study demonstrates that over-expression of human SIRT1 selectively in adipose tissue of mice prevents ageing-induced deterioration of insulin sensitivity and ectopic lipid distribution, reduces whole body fat mass and enhances locomotor activity. During ageing, the water-soluble vitamin biotin is progressively accumulated in adipose tissue. Over-expression of SIRT1 alleviates ageing-associated biotin accumulation and reduces the amount of biotinylated proteins, including acetyl CoA carboxylase, a major reservoir of biotin in adipose tissues. Chronic biotin supplementation increases adipose biotin contents and abolishes adipose SIRT1-mediated beneficial effects on insulin sensitivity, lipid metabolism and locomotor activity. Biochemical, spectrometric and chromatographic analysis revealed that biotin and its metabolites act as competitive inhibitors of SIRT1-mediated deacetylation. In summary, these results demonstrate that adipose SIRT1 is a key player in maintaining systemic energy homeostasis and insulin sensitivity; enhancing its activity solely in adipose tissue can prevent ageing-associated metabolic disorders.
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Affiliation(s)
- Cheng Xu
- Department of Pharmacology and Pharmacy, The University of Hong KongHong Kong, China
| | - Bo Bai
- Department of Pharmacology and Pharmacy, The University of Hong KongHong Kong, China
| | - Pengcheng Fan
- Department of Pharmacology and Pharmacy, The University of Hong KongHong Kong, China
| | - Yu Cai
- Department of Pharmacology and Pharmacy, The University of Hong KongHong Kong, China
| | - Bosheng Huang
- Department of Pharmacology and Pharmacy, The University of Hong KongHong Kong, China
| | - Ivy KM Law
- Department of Pharmacology and Pharmacy, The University of Hong KongHong Kong, China
| | - Ling Liu
- Department of Pharmacology and Pharmacy, The University of Hong KongHong Kong, China
| | - Aimin Xu
- Department of Pharmacology and Pharmacy, The University of Hong KongHong Kong, China
| | - Chunling Tung
- Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong KongHong Kong, China
| | - Xuechen Li
- Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong KongHong Kong, China
| | - Fung-Ming Siu
- Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong KongHong Kong, China
| | - Chi-Ming Che
- Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong KongHong Kong, China
| | - Paul M Vanhoutte
- Department of Pharmacology and Pharmacy, The University of Hong KongHong Kong, China
| | - Yu Wang
- Department of Pharmacology and Pharmacy, The University of Hong KongHong Kong, China
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