1
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Chao CF, Pesch YY, Yu H, Wang C, Aristizabal MJ, Huan T, Tanentzapf G, Rideout E. An important role for triglyceride in regulating spermatogenesis. eLife 2024; 12:RP87523. [PMID: 38805376 PMCID: PMC11132686 DOI: 10.7554/elife.87523] [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] [Indexed: 05/30/2024] Open
Abstract
Drosophila is a powerful model to study how lipids affect spermatogenesis. Yet, the contribution of neutral lipids, a major lipid group which resides in organelles called lipid droplets (LD), to sperm development is largely unknown. Emerging evidence suggests LD are present in the testis and that loss of neutral lipid- and LD-associated genes causes subfertility; however, key regulators of testis neutral lipids and LD remain unclear. Here, we show LD are present in early-stage somatic and germline cells within the Drosophila testis. We identified a role for triglyceride lipase brummer (bmm) in regulating testis LD, and found that whole-body loss of bmm leads to defects in sperm development. Importantly, these represent cell-autonomous roles for bmm in regulating testis LD and spermatogenesis. Because lipidomic analysis of bmm mutants revealed excess triglyceride accumulation, and spermatogenic defects in bmm mutants were rescued by genetically blocking triglyceride synthesis, our data suggest that bmm-mediated regulation of triglyceride influences sperm development. This identifies triglyceride as an important neutral lipid that contributes to Drosophila sperm development, and reveals a key role for bmm in regulating testis triglyceride levels during spermatogenesis.
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Affiliation(s)
- Charlotte F Chao
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British ColumbiaVancouverCanada
| | - Yanina-Yasmin Pesch
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British ColumbiaVancouverCanada
| | - Huaxu Yu
- Department of Chemistry, The University of British ColumbiaVancouverCanada
| | - Chenjingyi Wang
- Department of Chemistry, The University of British ColumbiaVancouverCanada
| | | | - Tao Huan
- Department of Chemistry, The University of British ColumbiaVancouverCanada
| | - Guy Tanentzapf
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British ColumbiaVancouverCanada
| | - Elizabeth Rideout
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British ColumbiaVancouverCanada
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2
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Xu L, Li L, Wu L, Li P, Chen FJ. CIDE proteins and their regulatory mechanisms in lipid droplet fusion and growth. FEBS Lett 2024; 598:1154-1169. [PMID: 38355218 DOI: 10.1002/1873-3468.14823] [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: 10/28/2023] [Revised: 12/19/2023] [Accepted: 01/04/2024] [Indexed: 02/16/2024]
Abstract
The cell death-inducing DFF45-like effector (CIDE) proteins, including Cidea, Cideb, and Cidec/Fsp27, regulate various aspects of lipid homeostasis, including lipid storage, lipolysis, and lipid secretion. This review focuses on the physiological roles of CIDE proteins based on studies on knockout mouse models and human patients bearing CIDE mutations. The primary cellular function of CIDE proteins is to localize to lipid droplets (LDs) and to control LD fusion and growth across different cell types. We propose a four-step process of LD fusion, characterized by (a) the recruitment of CIDE proteins to the LD surface and CIDE movement, (b) the enrichment and condensate formation of CIDE proteins to form LD fusion plates at LD-LD contact sites, (c) lipid transfer through lipid-permeable passageways within the fusion plates, and (d) the completion of LD fusion. Lastly, we outline CIDE-interacting proteins as regulatory factors, as well as their contribution in LD fusion.
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Affiliation(s)
- Li Xu
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Lizhen Li
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Lingzhi Wu
- College of Future Technology, Peking University, Beijing, China
| | - Peng Li
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
- Tianjian Laboratory of Advanced Biomedical Sciences, Zhengzhou University, China
| | - Feng-Jung Chen
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
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3
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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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4
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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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5
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Bussmann H, Bremer S, Häberlein H, Boonen G, Drewe J, Butterweck V, Franken S. Impact of St. John's wort extract Ze 117 on stress induced changes in the lipidome of PBMC. Mol Med 2023; 29:50. [PMID: 37029349 PMCID: PMC10082490 DOI: 10.1186/s10020-023-00644-3] [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: 12/09/2022] [Accepted: 03/22/2023] [Indexed: 04/09/2023] Open
Abstract
BACKGROUND Membrane lipids have an important function in the brain as they not only provide a physical barrier segregating the inner and outer cellular environments, but are also involved in cell signaling. It has been shown that the lipid composition effects membrane fluidity which affects lateral mobility and activity of membrane-bound receptors. METHODS Since changes in cellular membrane properties are considered to play an important role in the development of depression, the effect of St. John's wort extract Ze 117 on plasma membrane fluidity in peripheral blood mononuclear cells (PBMC) was investigated using fluorescence anisotropy measurements. Changes in fatty acid residues in phospholipids after treatment of cortisol-stressed [1 μM] PBMCs with Ze 117 [10-50 µg/ml] were analyzed by mass spectrometry. RESULTS Cortisol increased membrane fluidity significantly by 3%, co-treatment with Ze 117 [50 µg/ml] counteracted this by 4.6%. The increased membrane rigidity by Ze 117 in cortisol-stressed [1 μM] PBMC can be explained by a reduced average number of double bonds and shortened chain length of fatty acid residues in phospholipids, as shown by lipidomics experiments. CONCLUSION The increase in membrane rigidity after Ze 117 treatment and therefore the ability to normalize membrane structure points to a new mechanism of antidepressant action of the extract.
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Affiliation(s)
- Hendrik Bussmann
- Max Zeller Söhne AG, Seeblickstrasse 4, 8590, Romanshorn, Switzerland
| | - Swen Bremer
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Nussallee 11, 53115, Bonn, Germany
| | - Hanns Häberlein
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Nussallee 11, 53115, Bonn, Germany
| | - Georg Boonen
- Max Zeller Söhne AG, Seeblickstrasse 4, 8590, Romanshorn, Switzerland
| | - Jürgen Drewe
- Max Zeller Söhne AG, Seeblickstrasse 4, 8590, Romanshorn, Switzerland
| | | | - Sebastian Franken
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Nussallee 11, 53115, Bonn, Germany.
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6
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Talbott HA, Plewes MR, Krause C, Hou X, Zhang P, Rizzo WB, Wood JR, Cupp AS, Davis JS. Formation and characterization of lipid droplets of the bovine corpus luteum. Sci Rep 2020; 10:11287. [PMID: 32647143 PMCID: PMC7347867 DOI: 10.1038/s41598-020-68091-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 06/18/2020] [Indexed: 12/21/2022] Open
Abstract
Establishment and maintenance of pregnancy depends on progesterone synthesized by luteal tissue in the ovary. Our objective was to identify the characteristics of lipid droplets (LDs) in ovarian steroidogenic cells. We hypothesized that LDs are a major feature of steroidogenic luteal cells and store cholesteryl esters. Whole bovine tissues, isolated ovarian steroidogenic cells (granulosa, theca, small luteal, and large luteal), and isolated luteal LDs were assessed for LD content, LD-associated proteins and lipid analyses. Bovine luteal tissue contained abundant lipid droplets, LD-associated perilipins 2/3/5, hormone-sensitive lipase, and 1-acylglycerol-3-phosphate O-acyltransferase ABHD5. Luteal tissue was enriched in triglycerides (TGs) compared to other tissues, except for adipose tissue. Luteal cells were distinguishable from follicular cells by the presence of LDs, LD-associated proteins, and increased TGs. Furthermore, LDs from large luteal cells were numerous and small; whereas, LDs from small luteal cells were large and less numerous. Isolated LDs contained nearly all of the TGs and cholesteryl esters present in luteal tissue. Isolated luteal LDs were composed primarily of TG, with lesser amounts of cholesteryl esters, diglyceride and other phospholipids. Bovine luteal LDs are distinct from LDs in other bovine tissues, including follicular steroidogenic cells.
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Affiliation(s)
- Heather A Talbott
- Department of Obstetrics and Gynecology, Olson Center for Women's Health, University of Nebraska Medical Center, Omaha, NE, 68198-9450, USA.,Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, 68198-5870, USA.,Division of Reproductive and Developmental Sciences, Oregon Health Sciences University/Oregon National Primate Research Center, Beaverton, OR, 97006, USA
| | - Michele R Plewes
- Department of Obstetrics and Gynecology, Olson Center for Women's Health, University of Nebraska Medical Center, Omaha, NE, 68198-9450, USA.,Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, 68105, USA
| | - Crystal Krause
- Department of Obstetrics and Gynecology, Olson Center for Women's Health, University of Nebraska Medical Center, Omaha, NE, 68198-9450, USA.,Surgery Department, University of Nebraska Medical Center, Omaha, NE, 68198-3280, USA
| | - Xiaoying Hou
- Department of Obstetrics and Gynecology, Olson Center for Women's Health, University of Nebraska Medical Center, Omaha, NE, 68198-9450, USA
| | - Pan Zhang
- Department of Obstetrics and Gynecology, Olson Center for Women's Health, University of Nebraska Medical Center, Omaha, NE, 68198-9450, USA
| | - William B Rizzo
- Department of Pediatrics, University of Nebraska Medical Center, Omaha, NE, 68198-5940, USA
| | - Jennifer R Wood
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, 68583-0908, USA
| | - Andrea S Cupp
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE, 68583-0908, USA
| | - John S Davis
- Department of Obstetrics and Gynecology, Olson Center for Women's Health, University of Nebraska Medical Center, Omaha, NE, 68198-9450, USA. .,Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, 68198-5870, USA. .,Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, 68105, USA.
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7
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Yamamuro D, Takahashi M, Nagashima S, Wakabayashi T, Yamazaki H, Takei A, Takei S, Sakai K, Ebihara K, Iwasaki Y, Yada T, Ishibashi S. Peripheral circadian rhythms in the liver and white adipose tissue of mice are attenuated by constant light and restored by time-restricted feeding. PLoS One 2020; 15:e0234439. [PMID: 32530967 PMCID: PMC7292356 DOI: 10.1371/journal.pone.0234439] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 05/25/2020] [Indexed: 12/13/2022] Open
Abstract
Disturbance of circadian rhythms underlies various metabolic diseases. Constant light exposure (LL) is known to disrupt both central and peripheral circadian rhythms. Here, we attempted to determine whether the effects of LL are different between various peripheral tissues and whether time-restricted feeding restores the circadian rhythms especially in white adipose tissue (WAT). Six-week-old mice were subjected to three feeding regimes: ad libitum feeding under light/dark phase (LD), ad libitum feeding under LL cycle, and restricted feeding at night-time under LL cycle with a normal chow. After 3 weeks, we compared body weight, food intake, plasma levels of lipids and glucose, and the expression patterns of the clock genes and the genes involved in lipid metabolism in the liver and WAT. The mice kept under LL with or without time-restricted feeding were 5.2% heavier (p<0.001, n = 16) than the mice kept under LD even though the food intakes of the two groups were the same. Food intake occurred mostly in the dark phase. LL disrupted this pattern, causing disruptions in circadian rhythms of plasma levels of triglycerides (TG) and glucose. Time-restricted feeding partially restored the rhythms. LL eliminated the circadian rhythms of the expression of the clock genes as well as most of the genes involved in lipid metabolism in both liver and WAT. More notably, LL markedly decreased not only the amplitude but also the average levels of the expression of the genes in the liver, but not in the WAT, suggesting that transcription in the liver is sensitive to constant light exposure. Time-restricted feeding restored the circadian rhythms of most of the genes to various degrees in both liver and WAT. In conclusion, LL disrupted the peripheral circadian rhythms more severely in liver than in WAT. Time-restricted feeding restored the circadian rhythms in both tissues.
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Affiliation(s)
- Daisuke Yamamuro
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Manabu Takahashi
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Shuichi Nagashima
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Tetsuji Wakabayashi
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Hisataka Yamazaki
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Akihito Takei
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Shoko Takei
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Kent Sakai
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Ken Ebihara
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Yusaku Iwasaki
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
| | - Toshihiko Yada
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
| | - Shun Ishibashi
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi, Japan
- * E-mail:
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8
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Niyogi S, Ghosh M, Adak M, Chakrabarti P. PEDF promotes nuclear degradation of ATGL through COP1. Biochem Biophys Res Commun 2019; 512:806-811. [PMID: 30926171 DOI: 10.1016/j.bbrc.2019.03.111] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 03/18/2019] [Indexed: 12/12/2022]
Abstract
Adipose triglyceride lipase (ATGL) plays a compelling role in hepatic lipid turnover and in the pathophysiology of non-alcoholic fatty liver disease. Hepatic ATGL is post-transcriptionally regulated by E3 ubiquitin ligase constitutive photomorphogenic1 (COP1) through polyubiquitylation and proteasomal degradation. However the physiological cue for COP1-mediated hepatocellular degradation of ATGL remained unknown. Here we checked for the role of pigment epithelium-derived factor (PEDF), a moonlighting hepatokine and the so-called ligand of ATGL for its stability in hepatocytes. We show that PEDF diminishes ATGL protein stability by promoting its proteasomal degradation in COP1-dependent manner. Despite being a secretory glycoprotein, PEDF is also sequestered in the nuclear compartment so as COP1. Interestingly, PEDF enhances nuclear import of predominantly cytosolic ATGL protein for its subsequent proteasomal degradation in the nucleus. PEDF also controls cell autonomous hepatocyte lipid accumulation and mobilization through COP1-ATGL axis, thereby unraveling a novel pathway for hepatic lipid metabolism.
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Affiliation(s)
- Sougata Niyogi
- Division of Cell Biology and Physiology, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Mainak Ghosh
- Division of Cell Biology and Physiology, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Moumita Adak
- Division of Cell Biology and Physiology, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Partha Chakrabarti
- Division of Cell Biology and Physiology, CSIR-Indian Institute of Chemical Biology, Kolkata, India; Academy of Innovative and Scientific Research, India.
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9
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Welte MA, Gould AP. Lipid droplet functions beyond energy storage. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1260-1272. [PMID: 28735096 PMCID: PMC5595650 DOI: 10.1016/j.bbalip.2017.07.006] [Citation(s) in RCA: 331] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/17/2017] [Accepted: 07/17/2017] [Indexed: 02/07/2023]
Abstract
Lipid droplets are cytoplasmic organelles that store neutral lipids and are critically important for energy metabolism. Their function in energy storage is firmly established and increasingly well characterized. However, emerging evidence indicates that lipid droplets also play important and diverse roles in the cellular handling of lipids and proteins that may not be directly related to energy homeostasis. Lipid handling roles of droplets include the storage of hydrophobic vitamin and signaling precursors, and the management of endoplasmic reticulum and oxidative stress. Roles of lipid droplets in protein handling encompass functions in the maturation, storage, and turnover of cellular and viral polypeptides. Other potential roles of lipid droplets may be connected with their intracellular motility and, in some cases, their nuclear localization. This diversity highlights that lipid droplets are very adaptable organelles, performing different functions in different biological contexts. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
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Affiliation(s)
- Michael A Welte
- Department of Biology, University of Rochester, Rochester, NY, United States.
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10
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Ghosh M, Niyogi S, Bhattacharyya M, Adak M, Nayak DK, Chakrabarti S, Chakrabarti P. Ubiquitin Ligase COP1 Controls Hepatic Fat Metabolism by Targeting ATGL for Degradation. Diabetes 2016; 65:3561-3572. [PMID: 27658392 DOI: 10.2337/db16-0506] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 09/14/2016] [Indexed: 11/13/2022]
Abstract
Optimal control of hepatic lipid metabolism is critical for organismal metabolic fitness. In liver, adipose triglyceride lipase (ATGL) serves as a major triacylglycerol (TAG) lipase and controls the bulk of intracellular lipid turnover. However, regulation of ATGL expression and its functional implications in hepatic lipid metabolism, particularly in the context of fatty liver disease, is unclear. We show that E3 ubiquitin ligase COP1 (also known as RFWD2) binds to the consensus VP motif of ATGL and targets it for proteasomal degradation by K-48 linked polyubiquitination, predominantly at the lysine 100 residue. COP1 thus serves as a critical regulator of hepatocyte TAG content, fatty acid mobilization, and oxidation. Moreover, COP1-mediated regulation of hepatic lipid metabolism requires optimum ATGL expression for its metabolic outcome. In vivo, adenovirus-mediated depletion of COP1 ameliorates high-fat diet-induced steatosis in mouse liver and improves liver function. Our study thus provides new insights into the regulation of hepatic lipid metabolism by the ubiquitin-proteasome system and suggests COP1 as a potential therapeutic target for nonalcoholic fatty liver disease.
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Affiliation(s)
- Mainak Ghosh
- Division of Cell Biology and Physiology, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, India
| | - Sougata Niyogi
- Division of Cell Biology and Physiology, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, India
| | - Madhumita Bhattacharyya
- Division of Structural Biology and Bioinformatics, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, India
| | - Moumita Adak
- Division of Cell Biology and Physiology, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, India
| | - Dipak K Nayak
- Nuclear Medicine Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, India
| | - Saikat Chakrabarti
- Division of Structural Biology and Bioinformatics, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, India
| | - Partha Chakrabarti
- Division of Cell Biology and Physiology, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata, India
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Ballestri S, Zona S, Targher G, Romagnoli D, Baldelli E, Nascimbeni F, Roverato A, Guaraldi G, Lonardo A. Nonalcoholic fatty liver disease is associated with an almost twofold increased risk of incident type 2 diabetes and metabolic syndrome. Evidence from a systematic review and meta-analysis. J Gastroenterol Hepatol 2016; 31:936-44. [PMID: 26667191 DOI: 10.1111/jgh.13264] [Citation(s) in RCA: 479] [Impact Index Per Article: 59.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 12/05/2015] [Accepted: 12/07/2015] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIM The magnitude of the risk of incident type 2 diabetes (T2D) and metabolic syndrome (MetS) among patients with nonalcoholic fatty liver disease (NAFLD) is poorly known. We gauged the risk of developing T2D and MetS in patients with NAFLD diagnosed by either serum liver enzymes (aminotransferases or gamma-glutamyltransferase [GGT]) or ultrasonography. METHODS Pertinent prospective studies were identified through extensive electronic database research, and studies fulfilling enrolment criteria were included in the meta-analysis. RESULTS Overall, in a pooled population of 117020 patients (from 20 studies), who were followed-up for a median period of 5 years (range: 3-14.7 years), NAFLD was associated with an increased risk of incident T2D with a pooled relative risk of 1.97 (95% confidence interval [CI], 1.80-2.15) for alanine aminotransferase, 1.58 (95% CI, 1.43-1.74) for aspartate aminotransferase, 1.86 (95% CI, 1.71-2.03) for GGT (last vs first quartile or quintile), and 1.86 (95% CI, 1.76-1.95) for ultrasonography, respectively. Overall, in a pooled population of 81411 patients (from eight studies) who were followed-up for a median period of 4.5 years (range: 3-11 years), NAFLD was associated with an increased risk of incident MetS with a pooled relative risk of 1.80 (95% CI, 1.72-1.89) for alanine aminotransferase (last vs first quartile or quintile), 1.98 (95% CI, 1.89-2.07) for GGT, and 3.22 (95% CI, 3.05-3.41) for ultrasonography, respectively. CONCLUSIONS Nonalcoholic fatty liver disease, as diagnosed by either liver enzymes or ultrasonography, significantly increases the risk of incident T2D and MetS over a median 5-year follow-up.
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Affiliation(s)
| | - Stefano Zona
- University of Modena and Reggio Emilia, Metabolic Clinic, Infectious and Tropical Disease Unit, Policlinico Hospital, Modena, Italy
| | - Giovanni Targher
- Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Verona and Azienda Ospedaliera Universitaria Integrata di Verona, Verona, Italy
| | - Dante Romagnoli
- Azienda USL, Outpatient Liver Clinic and Internal Medicine, NOCSAE, Modena, Italy
| | - Enrica Baldelli
- Azienda USL, Outpatient Liver Clinic and Internal Medicine, NOCSAE, Modena, Italy
| | - Fabio Nascimbeni
- Azienda USL, Outpatient Liver Clinic and Internal Medicine, NOCSAE, Modena, Italy
| | | | - Giovanni Guaraldi
- University of Modena and Reggio Emilia, Metabolic Clinic, Infectious and Tropical Disease Unit, Policlinico Hospital, Modena, Italy
| | - Amedeo Lonardo
- Azienda USL, Outpatient Liver Clinic and Internal Medicine, NOCSAE, Modena, Italy
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Soares AF, Lei H, Gruetter R. Characterization of hepatic fatty acids in mice with reduced liver fat by ultra-short echo time (1)H-MRS at 14.1 T in vivo. NMR IN BIOMEDICINE 2015; 28:1009-1020. [PMID: 26119835 DOI: 10.1002/nbm.3345] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 05/19/2015] [Accepted: 05/20/2015] [Indexed: 06/04/2023]
Abstract
Alterations in the hepatic lipid content (HLC) and fatty acid composition are associated with disruptions in whole body metabolism, both in humans and in rodent models, and can be non-invasively assessed by (1)H-MRS in vivo. We used (1)H-MRS to characterize the hepatic fatty-acyl chains of healthy mice and to follow changes caused by streptozotocin (STZ) injection. Using STEAM at 14.1 T with an ultra-short TE of 2.8 ms, confounding effects from T2 relaxation and J-coupling were avoided, allowing for accurate estimations of the contribution of unsaturated (UFA), saturated (SFA), mono-unsaturated (MUFA) and poly-unsaturated (PUFA) fatty-acyl chains, number of double bonds, PU bonds and mean chain length. Compared with in vivo (1) H-MRS, high resolution NMR performed in vitro in hepatic lipid extracts reported longer fatty-acyl chains (18 versus 15 carbons) with a lower contribution from UFA (61 ± 1% versus 80 ± 5%) but a higher number of PU bonds per UFA (1.39 ± 0.03 versus 0.58 ± 0.08), driven by the presence of membrane species in the extracts. STZ injection caused a decrease of HLC (from 1.7 ± 0.3% to 0.7 ± 0.1%), an increase in the contribution of SFA (from 21 ± 2% to 45 ± 6%) and a reduction of the mean length (from 15 to 13 carbons) of cytosolic fatty-acyl chains. In addition, SFAs were also likely to have increased in membrane lipids of STZ-induced diabetic mice, along with a decrease of the mean chain length. These studies show the applicability of (1)H-MRS in vivo to monitor changes in the composition of the hepatic fatty-acyl chains in mice even when they exhibit reduced HLC, pointing to the value of this methodology to evaluate lipid-lowering interventions in the scope of metabolic disorders.
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Affiliation(s)
- Ana Francisca Soares
- Laboratory for Functional and Metabolic Imaging (LIFMET), École Polytechinque Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Hongxia Lei
- Center for Biomedical Imaging (CIBM), Lausanne, Switzerland
- Department of Radiology, University of Geneva (UNIGE), Geneva, Switzerland
| | - Rolf Gruetter
- Laboratory for Functional and Metabolic Imaging (LIFMET), École Polytechinque Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Department of Radiology, University of Geneva (UNIGE), Geneva, Switzerland
- Department of Radiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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Hartler J, Köfeler HC, Trötzmüller M, Thallinger GG, Spener F. Assessment of lipidomic species in hepatocyte lipid droplets from stressed mouse models. Sci Data 2014; 1:140051. [PMID: 25977802 PMCID: PMC4421934 DOI: 10.1038/sdata.2014.51] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 11/18/2014] [Indexed: 01/30/2023] Open
Abstract
Lipid droplets are considered to be the hub for storage and metabolism of cellular lipids. In previous work we have phenotyped the lipidome of murine hepatocyte lipid droplets using liquid chromatography-mass spectrometry (UHPLC-MS) plus integrated MS/MS, followed by automatic analysis of the MS data. The organelles were isolated after intervention studies involving nutritional stress (extended feeding of a high fat diet or short term fasting), genetic stress due to knock-out of adipocyte triglyceride lipase, or by combined application of nutritional and genetic stress together ('super stress'). Lipidomics at the level of lipid species (profiling of lipid classes) and lipid molecular species (structural analysis in parallel) has unraveled clear lipid droplet phenotypes as judged by patterns seen best in triacylglycerol (TG) lipidomes, but also in diacylglycerol and phosphatidylcholine lipidomes. The combined view of these data presented here validates the methods used and provides high quality lipidomic data for further bioinformatic inspections. Examples are given for identification of TG species subsets considered surrogates for whole TG lipidomes.
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Affiliation(s)
- Jürgen Hartler
- Bioinformatics Group, Institute for Knowledge Discovery, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
- Omics Center Graz, Stiftingtalstr. 24, 8010 Graz, Austria
| | - Harald C Köfeler
- Core Facility Mass Spectrometry, ZMF, Medical University of Graz, Stiftingtalstr. 24, 8010 Graz, Austria
| | - Martin Trötzmüller
- Core Facility Mass Spectrometry, ZMF, Medical University of Graz, Stiftingtalstr. 24, 8010 Graz, Austria
| | - Gerhard G Thallinger
- Bioinformatics Group, Institute for Knowledge Discovery, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
- Omics Center Graz, Stiftingtalstr. 24, 8010 Graz, Austria
| | - Friedrich Spener
- Department of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
- Department of Molecular Biosciences, University of Graz, Heinrichstr. 31, 8010 Graz, Austria
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Lim JW, Dillon J, Miller M. Proteomic and genomic studies of non-alcoholic fatty liver disease - clues in the pathogenesis. World J Gastroenterol 2014; 20:8325-8340. [PMID: 25024592 PMCID: PMC4093687 DOI: 10.3748/wjg.v20.i26.8325] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 01/14/2014] [Accepted: 04/03/2014] [Indexed: 02/06/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a widely prevalent hepatic disorder that covers wide spectrum of liver pathology. NAFLD is strongly associated with liver inflammation, metabolic hyperlipidaemia and insulin resistance. Frequently, NAFLD has been considered as the hepatic manifestation of metabolic syndrome. The pathophysiology of NAFLD has not been fully elucidated. Some patients can remain in the stage of simple steatosis, which generally is a benign condition; whereas others can develop liver inflammation and progress into non-alcoholic steatohepatitis, fibrosis, cirrhosis and hepatocellular carcinoma. The mechanism behind the progression is still not fully understood. Much ongoing proteomic researches have focused on discovering the unbiased circulating biochemical markers to allow early detection and treatment of NAFLD. Comprehensive genomic studies have also begun to provide new insights into the gene polymorphism to understand patient-disease variations. Therefore, NAFLD is considered a complex and mutifactorial disease phenotype resulting from environmental exposures acting on a susceptible polygenic background. This paper reviewed the current status of proteomic and genomic studies that have contributed to the understanding of NAFLD pathogenesis. For proteomics section, this review highlighted functional proteins that involved in: (1) transportation; (2) metabolic pathway; (3) acute phase reaction; (4) anti-inflammatory; (5) extracellular matrix; and (6) immune system. In the genomic studies, this review will discuss genes which involved in: (1) lipolysis; (2) adipokines; and (3) cytokines production.
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