51
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Goh B, Kim J, Seo S, Kim TY. High-Throughput Measurement of Lipid Turnover Rates Using Partial Metabolic Heavy Water Labeling. Anal Chem 2018; 90:6509-6518. [DOI: 10.1021/acs.analchem.7b05428] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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52
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Bai J, Wang P, Liu Y, Zhang Y, Li Y, He Z, Hou L, Liang R. Formaldehyde alters triglyceride synthesis and very low-density lipoprotein secretion in a time-dependent manner. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2017; 56:15-20. [PMID: 28866046 DOI: 10.1016/j.etap.2017.08.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 08/26/2017] [Indexed: 05/10/2023]
Abstract
Formaldehyde is a common indoor air pollutant that is toxic to the liver. This study aimed to investigate the effects of formaldehyde on triglyceride metabolism in human hepatocellular carcinoma cells (HepG2). Cell viability was detected using a MTT (3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide) assay. Following treatment with different concentrations of formaldehyde for 24 and 48h, the intra and extra-hepatocellular triglyceride (TG) content was determined using a chemical-enzymatic method; Western blotting was used to detect the levels of fatty acid synthesis and VLDL-related proteins. Our results showed that cell viability significantly decreased after formaldehyde treatment (0.5-12.5mM, 24/48h). Extracellular TG levels in the hepatocytes increased after formaldehyde treatment at 0.004mM-0.1mM for 24h. SREBP-1c, ACC, FASN, and MTP, CES3 and DGAT1 proteins increased significantly after 24h of formaldehyde treatment. Intracellular TG levels decreased for 48h treatment of formaldehyde. AMPKα increased significantly in all tested groups and p-AMPK increased significantly after 0.1mM formaldehyde treatment for 48h. Our results indicated that short-term formaldehyde exposure balances triglyceride metabolism by promoting hepatocellular TG synthesis and VLDL secretion; Long-term formaldehyde disturbs the TG metabolism balance in the hepatocytes.
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Affiliation(s)
- Jianying Bai
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, PR China.
| | - Pan Wang
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, PR China
| | - Yanfei Liu
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, PR China
| | - Yan Zhang
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, PR China
| | - Yaofu Li
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, PR China
| | - Zhen He
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, PR China
| | - Lifang Hou
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, PR China; Center for Population Epigenetics, Robert H. Lurie Comprehensive Cancer Center and Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Ruifeng Liang
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, PR China
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53
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Abstract
Lipid droplets (LDs) are ubiquitous organelles that store neutral lipids for energy or membrane synthesis and act as hubs for metabolic processes. Cells generate LDs de novo, converting cells to emulsions with LDs constituting the dispersed oil phase in the aqueous cytoplasm. Here we review our current view of LD biogenesis. We present a model of LD formation from the ER in distinct steps and highlight the biology of proteins that govern this biophysical process. Areas of incomplete knowledge are identified, as are connections with physiology and diseases linked to alterations in LD biology.
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Affiliation(s)
- Tobias C Walther
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115; , .,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115.,Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142.,Howard Hughes Medical Institute, Boston, Massachusetts 02115
| | - Jeeyun Chung
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115; , .,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Robert V Farese
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115; , .,Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115.,Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142
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54
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Bruntz RC, Lane AN, Higashi RM, Fan TWM. Exploring cancer metabolism using stable isotope-resolved metabolomics (SIRM). J Biol Chem 2017; 292:11601-11609. [PMID: 28592486 PMCID: PMC5512057 DOI: 10.1074/jbc.r117.776054] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Metabolic reprogramming is a hallmark of cancer. The changes in metabolism are adaptive to permit proliferation, survival, and eventually metastasis in a harsh environment. Stable isotope-resolved metabolomics (SIRM) is an approach that uses advanced approaches of NMR and mass spectrometry to analyze the fate of individual atoms from stable isotope-enriched precursors to products to deduce metabolic pathways and networks. The approach can be applied to a wide range of biological systems, including human subjects. This review focuses on the applications of SIRM to cancer metabolism and its use in understanding drug actions.
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Affiliation(s)
- Ronald C Bruntz
- Center for Environmental and Systems Biochemistry, Markey Cancer Center, Lexington, Kentucky 40506; Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky 40506
| | - Andrew N Lane
- Center for Environmental and Systems Biochemistry, Markey Cancer Center, Lexington, Kentucky 40506; Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky 40506.
| | - Richard M Higashi
- Center for Environmental and Systems Biochemistry, Markey Cancer Center, Lexington, Kentucky 40506; Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky 40506
| | - Teresa W-M Fan
- Center for Environmental and Systems Biochemistry, Markey Cancer Center, Lexington, Kentucky 40506; Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky 40506.
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55
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Jung S, Choi M, Choi K, Kwon EB, Kang M, Kim DE, Jeong H, Kim J, Kim JH, Kim MO, Han SB, Cho S. Inactivation of human DGAT2 by oxidative stress on cysteine residues. PLoS One 2017; 12:e0181076. [PMID: 28700690 PMCID: PMC5507451 DOI: 10.1371/journal.pone.0181076] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/26/2017] [Indexed: 12/15/2022] Open
Abstract
Diacylglycerol acyltransferases (DGATs) have a crucial role in the biosynthesis of triacylglycerol (TG), the major storage form of metabolic energy in eukaryotic organisms. Even though DGAT2, one of two distinct DGATs, has a vital role in TG biosynthesis, little is known about the regulation of DGAT2 activity. In this study, we examined the role of cysteine and its oxidation in the enzymatic activity of human DGAT2 in vitro. Human DGAT2 activity was considerably inhibited not only by thiol-modifying reagents (NEM and IA) but also by ROS-related chemicals (H2O2 and β-lapachone), while human DGAT1 and GPAT1 were little affected. Particularly, ROS-related chemicals concomitantly induced intermolecular disulfide crosslinking of human DGAT2. Both the oxidative inactivation and disulfide crosslinking were almost completely reversed by the treatment with DTT, a disulfide-reducing agent. These results clearly demonstrated the significant role of ROS-induced intermolecular crosslinking in the inactivation of human DGAT2 and also suggested DGAT2 as a redox-sensitive regulator in TG biosynthesis.
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Affiliation(s)
- Sunhee Jung
- Anticancer Agent Research Center, Korea Research Institute of Bioscience & Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
- College of Pharmacy, Chungbuk National University, 1 Chungdae-ro Seowon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
| | - Miri Choi
- Anticancer Agent Research Center, Korea Research Institute of Bioscience & Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
- College of Pharmacy, Chungbuk National University, 1 Chungdae-ro Seowon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
| | - Kwangman Choi
- Anticancer Agent Research Center, Korea Research Institute of Bioscience & Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
| | - Eun Bin Kwon
- College of Pharmacy, Chungbuk National University, 1 Chungdae-ro Seowon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
- Natural Medicine Research Center, Korea Research Institute of Bioscience & Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
| | - Mingu Kang
- Anticancer Agent Research Center, Korea Research Institute of Bioscience & Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
- College of Pharmacy, Chungbuk National University, 1 Chungdae-ro Seowon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
| | - Dong-eun Kim
- Anticancer Agent Research Center, Korea Research Institute of Bioscience & Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
- College of Pharmacy, Chungbuk National University, 1 Chungdae-ro Seowon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
| | - Hyejeong Jeong
- Anticancer Agent Research Center, Korea Research Institute of Bioscience & Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
- College of Pharmacy, Chungbuk National University, 1 Chungdae-ro Seowon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
| | - Janghwan Kim
- Stem Cell Research Center, Korea Research Institute of Bioscience & Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon, South Korea
| | - Jong Heon Kim
- Cancer Cell and Molecular Biology Branch, Research Institute, National Cancer Center, Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, South Korea
| | - Mun Ock Kim
- Natural Medicine Research Center, Korea Research Institute of Bioscience & Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
| | - Sang-Bae Han
- College of Pharmacy, Chungbuk National University, 1 Chungdae-ro Seowon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
| | - Sungchan Cho
- Anticancer Agent Research Center, Korea Research Institute of Bioscience & Biotechnology, 30 Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-si, Chungcheongbuk-do, South Korea
- Department of Biomolecular Science, Korea University of Science and Technology, 217 Gajeong-ro, Daejeon, South Korea
- * E-mail:
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56
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Gluchowski NL, Becuwe M, Walther TC, Farese RV. Lipid droplets and liver disease: from basic biology to clinical implications. Nat Rev Gastroenterol Hepatol 2017; 14:343-355. [PMID: 28428634 PMCID: PMC6319657 DOI: 10.1038/nrgastro.2017.32] [Citation(s) in RCA: 400] [Impact Index Per Article: 57.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Lipid droplets are dynamic organelles that store neutral lipids during times of energy excess and serve as an energy reservoir during deprivation. Many prevalent metabolic diseases, such as the metabolic syndrome or obesity, often result in abnormal lipid accumulation in lipid droplets in the liver, also called hepatic steatosis. Obesity-related steatosis, or NAFLD in particular, is a major public health concern worldwide and is frequently associated with insulin resistance and type 2 diabetes mellitus. Here, we review the latest insights into the biology of lipid droplets and their role in maintaining lipid homeostasis in the liver. We also offer a perspective of liver diseases that feature lipid accumulation in these lipid storage organelles, which include NAFLD and viral hepatitis. Although clinical applications of this knowledge are just beginning, we highlight new opportunities for identifying molecular targets for treating hepatic steatosis and steatohepatitis.
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Affiliation(s)
- Nina L. Gluchowski
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, 655 Huntington Avenue, Boston, Massachusetts 02115, USA.,Boston Children’s Hospital Department of Gastroenterology, Hepatology and Nutrition, 300 Longwood Avenue Boston, Massachusetts 02115, USA
| | - Michel Becuwe
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, 655 Huntington Avenue, Boston, Massachusetts 02115, USA
| | - Tobias C. Walther
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, 655 Huntington Avenue, Boston, Massachusetts 02115, USA.,Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue Boston, Massachusetts 02115, USA.,Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur Boston, Massachusetts 02115, USA.,Howard Hughes Medical Institute, Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, 655 Huntington Avenue, Boston, Massachusetts 02115, USA
| | - Robert V. Farese
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, 655 Huntington Avenue, Boston, Massachusetts 02115, USA.,Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue Boston, Massachusetts 02115, USA.,Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur Boston, Massachusetts 02115, USA
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57
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Lane AN, Fan TWM. NMR-based Stable Isotope Resolved Metabolomics in systems biochemistry. Arch Biochem Biophys 2017; 628:123-131. [PMID: 28263717 DOI: 10.1016/j.abb.2017.02.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 02/24/2017] [Accepted: 02/27/2017] [Indexed: 01/23/2023]
Abstract
Metabolism is the basic activity of live cells, and monitoring the metabolic state provides a dynamic picture of the cells or tissues, and how they respond to external changes, for in disease or treatment with drugs. NMR is an extremely versatile analytical tool that can be applied to a wide range of biochemical problems. Despite its modest sensitivity its versatility make it an ideal tool for analyzing biochemical dynamics both in vitro and in vivo, especially when coupled with its isotope editing capabilities, from which isotope distributions can be readily determined. These are critical for any analyses of flux in live organisms. This review focuses on the utility of NMR spectroscopy in metabolomics, with an emphasis on NMR applications in stable isotope-enriched tracer research for elucidating biochemical pathways and networks with examples from nucleotide biochemistry. The knowledge gained from this area of research provides a ready link to genomic, epigenomic, transcriptomic, and proteomic information to achieve systems biochemical understanding of living cells and organisms.
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Affiliation(s)
- Andrew N Lane
- Center for Environmental Systems Biochemistry, University of Kentucky, USA; Department of Toxicology and Cancer Biology, University of Kentucky, USA.
| | - Teresa W-M Fan
- Center for Environmental Systems Biochemistry, University of Kentucky, USA; Department of Toxicology and Cancer Biology, University of Kentucky, USA
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58
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Irshad Z, Dimitri F, Christian M, Zammit VA. Diacylglycerol acyltransferase 2 links glucose utilization to fatty acid oxidation in the brown adipocytes. J Lipid Res 2017; 58:15-30. [PMID: 27836993 PMCID: PMC5234708 DOI: 10.1194/jlr.m068197] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 10/18/2016] [Indexed: 01/03/2023] Open
Abstract
Brown adipose tissue uptake of glucose and fatty acids is very high during nonshivering thermogenesis. Adrenergic stimulation markedly increases glucose uptake, de novo lipogenesis, and FA oxidation simultaneously. The mechanism that enables this concerted response has hitherto been unknown. Here, we find that in primary brown adipocytes and brown adipocyte-derived cell line (IMBAT-1), acute inhibition and longer-term knockdown of DGAT2 links the increased de novo synthesis of fatty acids from glucose to a pool of TAG that is simultaneously hydrolyzed, providing FA for mitochondrial oxidation. DGAT1 does not contribute to this pathway, but uses exogenous FA and glycerol to synthesize a functionally distinct pool of TAG to which DGAT2 also contributes. The DGAT2-dependent channelling of 14C from glucose into TAG and CO2 was reproduced in β3-agonist-stimulated primary brown adipocytes. Knockdown of DGAT2 in IMBAT-1 affected the mRNA levels of UCP1 and genes important in FA activation and esterification. Therefore, in β3-agonist activated brown adipocytes, DGAT2 specifically enables channelling of de novo synthesized FA into a rapidly mobilized pool of TAG, which is simultaneously hydrolyzed to provide substrates for mitochondrial fatty acid oxidation.
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Affiliation(s)
- Zehra Irshad
- Translational and Experimental Medicine, Division of Biomedical Sciences, Warwick Medical School, CV4 7AL, United Kingdom
| | - Federica Dimitri
- Translational and Experimental Medicine, Division of Biomedical Sciences, Warwick Medical School, CV4 7AL, United Kingdom
| | - Mark Christian
- Translational and Experimental Medicine, Division of Biomedical Sciences, Warwick Medical School, CV4 7AL, United Kingdom
| | - Victor A Zammit
- Translational and Experimental Medicine, Division of Biomedical Sciences, Warwick Medical School, CV4 7AL, United Kingdom
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59
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Ferguson D, Zhang J, Davis MA, Helsley RN, Vedin LL, Lee RG, Crooke RM, Graham MJ, Allende DS, Parini P, Brown JM. The lipid droplet-associated protein perilipin 3 facilitates hepatitis C virus-driven hepatic steatosis. J Lipid Res 2016; 58:420-432. [PMID: 27941027 DOI: 10.1194/jlr.m073734] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Indexed: 12/18/2022] Open
Abstract
Hepatitis C virus (HCV) is an enveloped RNA virus responsible for 170 million cases of viral hepatitis worldwide. Over 50% of chronically infected HCV patients develop hepatic steatosis, and steatosis can be induced by expression of HCV core protein (core) alone. Additionally, core must associate with cytoplasmic lipid droplets (LDs) for steatosis development and viral particle assembly. Due to the importance of the LD as a key component of hepatic lipid storage and as a platform for HCV particle assembly, it seems this dynamic subcellular organelle is a gatekeeper in the pathogenesis of viral hepatitis. Here, we hypothesized that core requires the host LD scaffold protein, perilipin (PLIN)3, to induce hepatic steatosis. To test our hypothesis in vivo, we have studied core-induced hepatic steatosis in the absence or presence of antisense oligonucleotide-mediated knockdown of PLIN3. PLIN3 knockdown blunted HCV core-induced steatosis in transgenic mice fed either chow or a moderate fat diet. Collectively, our studies demonstrate that the LD scaffold protein, PLIN3, is essential for HCV core-induced hepatic steatosis and provide new insights into the pathogenesis of HCV.
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Affiliation(s)
- Daniel Ferguson
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH.,Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC
| | - Jun Zhang
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC
| | - Matthew A Davis
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC
| | - Robert N Helsley
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH
| | - Lise-Lotte Vedin
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Richard G Lee
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Rosanne M Crooke
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Mark J Graham
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | | | - Paolo Parini
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - J Mark Brown
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH
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60
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Qi J, Lang W, Connelly MA, Du F, Liang Y, Caldwell GW, Martin T, Hansen MK, Kuo GH, Gaul MD, Pocai A, Lee S. Metabolic tracing of monoacylglycerol acyltransferase-2 activity in vitro and in vivo. Anal Biochem 2016; 524:68-75. [PMID: 27665677 DOI: 10.1016/j.ab.2016.09.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 09/01/2016] [Accepted: 09/19/2016] [Indexed: 01/24/2023]
Abstract
Monoacylglycerol acyltransferase 2 (MGAT2) catalyzes the synthesis of diacylglycerol (DAG) from free fatty acids (FFA) and sn-monoacylglycerol (MG), the two major hydrolysis products of dietary fat. To demonstrate MGAT2-mediated cellular activity of triglyceride (TG) synthesis, we utilized 1-oleoyl-glycerol-d5 as a substrate to trace MGAT2-driven 1-oleoyl-glycerol-d5 incorporation into TG in HEK293 cells stably expressing human MGAT2. The oleoyl-glycerol-d5 incorporated major TG species were then quantified by liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI/MS/MS) in a 96-well format. Conventional MGAT2 target-engagement in vivo assays measure the elevation of total plasma TG by orally dosing a bolus of TG oil. We developed a novel LC/ESI/MS/MS-based fat absorption assay to assess the ability of MGAT2 inhibitors to inhibit fat absorption in CD1 mice by a meal tolerance test consisting of a mixture of liquid Boost plus® and 0.59 g/kg U13C-TG oil. The newly resynthesized plasma heavy TGs containing three 13C in the glycerol backbone and two U13C-acyl-chains, which represented the digested, absorbed and resynthesized TGs, were then quantitated by LC/ESI/MS/MS. With this assay, we identified a potent MGAT2 inhibitor that blocked MGAT2-mediated activity in vitro and in vivo. The use of 1-oleoyl-glycerol-d5 and U13C-TG oil followed by LC/ESI/MS/MS detection of stable-isotopic labeled DAG, TG, or glycerol provides a wide range of applications to study pathophysiological regulation of the monoacylglycerol pathway and MGAT2 activity.
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Affiliation(s)
- Jenson Qi
- Cardiovascular and Metabolic Disease Research, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477-0776, USA.
| | - Wensheng Lang
- Discovery Sciences, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477-0776, USA
| | - Margery A Connelly
- Cardiovascular and Metabolic Disease Research, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477-0776, USA
| | - Fuyong Du
- Cardiovascular and Metabolic Disease Research, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477-0776, USA
| | - Yin Liang
- Cardiovascular and Metabolic Disease Research, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477-0776, USA
| | - Gary W Caldwell
- Discovery Sciences, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477-0776, USA
| | - Tonya Martin
- Cardiovascular and Metabolic Disease Research, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477-0776, USA
| | - Michael K Hansen
- Cardiovascular and Metabolic Disease Research, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477-0776, USA
| | - Gee-Hong Kuo
- Cardiovascular and Metabolic Disease Research, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477-0776, USA
| | - Michael D Gaul
- Cardiovascular and Metabolic Disease Research, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477-0776, USA
| | - Alessandro Pocai
- Cardiovascular and Metabolic Disease Research, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477-0776, USA
| | - Seunghun Lee
- Cardiovascular and Metabolic Disease Research, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477-0776, USA
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61
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Knockdown of triglyceride synthesis does not enhance palmitate lipotoxicity or prevent oleate-mediated rescue in rat hepatocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1005-1014. [PMID: 27249207 DOI: 10.1016/j.bbalip.2016.05.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 05/14/2016] [Accepted: 05/26/2016] [Indexed: 12/14/2022]
Abstract
Experiments in a variety of cell types, including hepatocytes, consistently demonstrate the acutely lipotoxic effects of saturated fatty acids, such as palmitate (PA), but not unsaturated fatty acids, such as oleate (OA). PA+OA co-treatment fully prevents PA lipotoxicity through mechanisms that are not well defined but which have been previously attributed to more efficient esterification and sequestration of PA into triglycerides (TGs) when OA is abundant. However, this hypothesis has never been directly tested by experimentally modulating the relative partitioning of PA/OA between TGs and other lipid fates in hepatocytes. In this study, we found that addition of OA to PA-treated hepatocytes enhanced TG synthesis, reduced total PA uptake and PA lipid incorporation, decreased phospholipid saturation and rescued PA-induced ER stress and lipoapoptosis. Knockdown of diacylglycerol acyltransferase (DGAT), the rate-limiting step in TG synthesis, significantly reduced TG accumulation without impairing OA-mediated rescue of PA lipotoxicity. In both wild-type and DGAT-knockdown hepatocytes, OA co-treatment significantly reduced PA lipid incorporation and overall phospholipid saturation compared to PA-treated hepatocytes. These data indicate that OA's protective effects do not require increased conversion of PA into inert TGs, but instead may be due to OA's ability to compete against PA for cellular uptake and/or esterification and, thereby, normalize the composition of cellular lipids in the presence of a toxic PA load.
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62
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Roberts JL, He B, Erickson A, Moreau R. Improvement of mTORC1-driven overproduction of apoB-containing triacylglyceride-rich lipoproteins by short-chain fatty acids, 4-phenylbutyric acid and (R)-α-lipoic acid, in human hepatocellular carcinoma cells. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:166-76. [DOI: 10.1016/j.bbalip.2015.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/24/2015] [Accepted: 12/07/2015] [Indexed: 01/22/2023]
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63
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Doler C, Schweiger M, Zimmermann R, Breinbauer R. Chemical Genetic Approaches for the Investigation of Neutral Lipid Metabolism. Chembiochem 2016; 17:358-77. [DOI: 10.1002/cbic.201500501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Indexed: 12/14/2022]
Affiliation(s)
- Carina Doler
- Institute of Organic Chemistry; Graz University of Technology; Stremayrgasse 9 8010 Graz Austria
| | - Martina Schweiger
- Institute of Molecular Biosciences; University of Graz; Heinrichstrasse 31/II 8010 Graz Austria
| | - Robert Zimmermann
- Institute of Molecular Biosciences; University of Graz; Heinrichstrasse 31/II 8010 Graz Austria
| | - Rolf Breinbauer
- Institute of Organic Chemistry; Graz University of Technology; Stremayrgasse 9 8010 Graz Austria
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64
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Kawabata K, Karahashi M, Sakamoto T, Tsuji Y, Yamazaki T, Okazaki M, Mitsumoto A, Kudo N, Kawashima Y. Fatty Acid β-Oxidation Plays a Key Role in Regulating cis-Palmitoleic Acid Levels in the Liver. Biol Pharm Bull 2016; 39:1995-2008. [DOI: 10.1248/bpb.b16-00470] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | | | | | - Yukiho Tsuji
- School of Pharmaceutical Sciences, Josai University
| | | | - Mari Okazaki
- School of Pharmaceutical Sciences, Josai University
| | | | - Naomi Kudo
- School of Pharmaceutical Sciences, Josai University
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65
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Identification of a 13 bp indel polymorphism in the 3'-UTR of DGAT2 gene associated with backfat thickness and lean percentage in pigs. Gene 2015; 576:729-33. [PMID: 26407871 DOI: 10.1016/j.gene.2015.09.047] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 09/16/2015] [Accepted: 09/19/2015] [Indexed: 11/22/2022]
Abstract
DGAT2 (acyl-CoA: diacylglycerol acyltransferase, EC2.3.1.20) is a member of acyl-CoA: monoacylglycerol acyltransferase (MGAT) family, which catalyzes one fatty acyl-CoA and diacylglycerol (DG) molecule to form triacylglycerols (TG) and is the final and rate-limiting step in the reaction of TG synthesis pathways. We previously showed that, during pig development, the fold change of DGAT2 mRNA in backfat tissue is much higher than that of DGAT1, implying that DGAT2 is more important in regulating porcine fat deposition. In this study, a 13 bp indel polymorphism located at 905 bp downstream from the stop codon (TGA) of porcine DGAT2 was found and two alleles of A (with 13 bp insertion) and B (no insertion) were designated. Allele A is dominant in all pig populations investigated. The backfat thickness of individuals with genotype AA is significantly lower than those with genotype AB (p<0.01), and the lean percentage of individuals with genotype AA is significantly higher than those with genotype AB (p<0.05) in Junmu No. 1 white pig population. The secondary structure of 3'-UTR without the 13 bp insertion is slightly less stable than with the 13 bp insertion type. In vitro assay indicates that, after differentiation, the luciferase activity was significantly higher for pGL3-B compared to pGL3-A vector (p<0.001). Moreover, the DGAT2 mRNA expression in the backfat tissue of pigs with genotype BB was significantly higher than AB in commercial DLY pigs (p<0.05). These results suggest that the 13bp indel polymorphism in the 3'-UTR of porcine DGAT2 most likely affects fat deposition by altering its expression in pigs.
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66
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Song XS, Zhang J, Chen X, Palyha O, Chung C, Sonatore LM, Wilsie L, Stout S, McLaren DG, Taggart A, Imbriglio JE, Pinto S, Garcia-Calvo M, Addona GH. Identification of DGAT2 Inhibitors Using Mass Spectrometry. ACTA ACUST UNITED AC 2015; 21:117-26. [DOI: 10.1177/1087057115607463] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 08/23/2015] [Indexed: 11/17/2022]
Abstract
Mass spectrometry offers significant advantages over other detection technologies in the areas of hit finding, hit validation, and medicinal chemistry compound optimization. The foremost obvious advantage is the ability to directly measure enzymatic product formation. In addition, the inherent sensitivity of the liquid chromatography/mass spectrometry (LC/MS) approach allows the execution of enzymatic assays at substrate concentrations typically at or below substrate Km. Another advantage of the LC/MS approach is the ability to assay impure enzyme systems that would otherwise be difficult to prosecute with traditional labeled methods. This approach was used to identify inhibitors of diacylglycerol O-acyltransferase-2 (DGAT2), a transmembrane enzyme involved in the triglyceride (TG) production pathway. The LC/MS approach was employed because of its increased assay window (compared with control membranes) of more than sevenfold compared with less than twofold with a conventional fluorogenic assay. The ability to generate thousands of dose-dependent IC50 data was made possible by the use of a staggered parallel LC/MS system with fast elution gradients. From the hit-deconvolution efforts, several structural scaffold series were identified that inhibit DGAT2 activity. Additional profiling of one chemotype in particular identified two promising reversible and selective compounds (compound 15 and compound 16) that effectively inhibit TG production in mouse primary hepatocytes.
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Affiliation(s)
- Xuelei S. Song
- Department of Pharmacology, Merck Research Laboratories, Boston, MA, USA
| | - Jiaping Zhang
- Department of Pharmacology, Merck Research Laboratories, Kenilworth, NJ, USA
| | - Xun Chen
- Department of Pharmacology, Merck Research Laboratories, Kenilworth, NJ, USA
| | - Oksana Palyha
- Atherosclerosis, Merck Research Laboratories, Kenilworth, NJ, USA
| | - Christine Chung
- Department of Pharmacology, Merck Research Laboratories, Kenilworth, NJ, USA
| | - Lisa M. Sonatore
- Department of Pharmacology, Merck Research Laboratories, Kenilworth, NJ, USA
| | - Larissa Wilsie
- Atherosclerosis, Merck Research Laboratories, Kenilworth, NJ, USA
| | - Steven Stout
- Department of Pharmacology, Merck Research Laboratories, Kenilworth, NJ, USA
| | - David G. McLaren
- Department of Pharmacology, Merck Research Laboratories, Kenilworth, NJ, USA
| | - Andrew Taggart
- Atherosclerosis, Merck Research Laboratories, Kenilworth, NJ, USA
| | | | - Shirly Pinto
- Atherosclerosis, Merck Research Laboratories, Kenilworth, NJ, USA
| | | | - George H. Addona
- Department of Pharmacology, Merck Research Laboratories, Boston, MA, USA
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67
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Futatsugi K, Kung DW, Orr STM, Cabral S, Hepworth D, Aspnes G, Bader S, Bian J, Boehm M, Carpino PA, Coffey SB, Dowling MS, Herr M, Jiao W, Lavergne SY, Li Q, Clark RW, Erion DM, Kou K, Lee K, Pabst BA, Perez SM, Purkal J, Jorgensen CC, Goosen TC, Gosset JR, Niosi M, Pettersen JC, Pfefferkorn JA, Ahn K, Goodwin B. Discovery and Optimization of Imidazopyridine-Based Inhibitors of Diacylglycerol Acyltransferase 2 (DGAT2). J Med Chem 2015; 58:7173-85. [DOI: 10.1021/acs.jmedchem.5b01006] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Kentaro Futatsugi
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Daniel W. Kung
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Suvi T. M. Orr
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Shawn Cabral
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - David Hepworth
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Gary Aspnes
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Scott Bader
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Jianwei Bian
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Markus Boehm
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Philip A. Carpino
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Steven B. Coffey
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Matthew S. Dowling
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Michael Herr
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Wenhua Jiao
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Sophie Y. Lavergne
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Qifang Li
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Ronald W. Clark
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Derek M. Erion
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Kou Kou
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Kyuha Lee
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Brandon A. Pabst
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Sylvie M. Perez
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Julie Purkal
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Csilla C. Jorgensen
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Theunis C. Goosen
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - James R. Gosset
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Mark Niosi
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - John C. Pettersen
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Jeffrey A. Pfefferkorn
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Kay Ahn
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
| | - Bryan Goodwin
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Worldwide Medicinal Chemistry, ⊥Cardiovascular, Metabolic and Endocrine Diseases Research Unit, #Pharmacokinetics, Dynamics and Metabolism, ∇Pharmaceutical Sciences, and ○Drug Safety Research & Development, Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
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68
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Huard K, Londregan AT, Tesz G, Bahnck KB, Magee TV, Hepworth D, Polivkova J, Coffey SB, Pabst BA, Gosset JR, Nigam A, Kou K, Sun H, Lee K, Herr M, Boehm M, Carpino PA, Goodwin B, Perreault C, Li Q, Jorgensen CC, Tkalcevic GT, Subashi TA, Ahn K. Discovery of Selective Small Molecule Inhibitors of Monoacylglycerol Acyltransferase 3. J Med Chem 2015; 58:7164-72. [PMID: 26258602 DOI: 10.1021/acs.jmedchem.5b01008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Inhibition of triacylglycerol (TAG) biosynthetic enzymes has been suggested as a promising strategy to treat insulin resistance, diabetes, dyslipidemia, and hepatic steatosis. Monoacylglycerol acyltransferase 3 (MGAT3) is an integral membrane enzyme that catalyzes the acylation of both monoacylglycerol (MAG) and diacylglycerol (DAG) to generate DAG and TAG, respectively. Herein, we report the discovery and characterization of the first selective small molecule inhibitors of MGAT3. Isoindoline-5-sulfonamide (6f, PF-06471553) selectively inhibits MGAT3 with high in vitro potency and cell efficacy. Because the gene encoding MGAT3 (MOGAT3) is found only in higher mammals and humans, but not in rodents, a transgenic mouse model expressing the complete human MOGAT3 was used to characterize the effects of 6f in vivo. In the presence of a combination of diacylglycerol acyltransferases 1 and 2 (DGAT1 and DGAT2) inhibitors, an oral administration of 6f exhibited inhibition of the incorporation of deuterium-labeled glycerol into TAG in this mouse model. The availability of a potent and selective chemical tool and a humanized mouse model described in this report should facilitate further dissection of the physiological function of MGAT3 and its role in lipid homeostasis.
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Affiliation(s)
- Kim Huard
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Allyn T Londregan
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Gregory Tesz
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Kevin B Bahnck
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Thomas V Magee
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - David Hepworth
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Jana Polivkova
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Steven B Coffey
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Brandon A Pabst
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - James R Gosset
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Anu Nigam
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Kou Kou
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Hao Sun
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Kyuha Lee
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Michael Herr
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Markus Boehm
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Philip A Carpino
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Bryan Goodwin
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Christian Perreault
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Qifang Li
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Csilla C Jorgensen
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - George T Tkalcevic
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Timothy A Subashi
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
| | - Kay Ahn
- Worldwide Medicinal Chemistry, ‡Cardiovascular, Metabolic and Endocrine Diseases Research Unit, and §Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Cambridge, Massachusetts 02139, United States.,Worldwide Medicinal Chemistry, ∥Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research & Development , Groton, Connecticut 06340, United States
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69
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Eichmann TO, Lass A. DAG tales: the multiple faces of diacylglycerol--stereochemistry, metabolism, and signaling. Cell Mol Life Sci 2015; 72:3931-52. [PMID: 26153463 PMCID: PMC4575688 DOI: 10.1007/s00018-015-1982-3] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 06/17/2015] [Accepted: 06/29/2015] [Indexed: 12/31/2022]
Abstract
The neutral lipids diacylglycerols (DAGs) are involved in a plethora of metabolic pathways. They function as components of cellular membranes, as building blocks for glycero(phospho)lipids, and as lipid second messengers. Considering their central role in multiple metabolic processes and signaling pathways, cellular DAG levels require a tight regulation to ensure a constant and controlled availability. Interestingly, DAG species are versatile in their chemical structure. Besides the different fatty acid species esterified to the glycerol backbone, DAGs can occur in three different stereo/regioisoforms, each with unique biological properties. Recent scientific advances have revealed that DAG metabolizing enzymes generate and distinguish different DAG isoforms, and that only one DAG isoform holds signaling properties. Herein, we review the current knowledge of DAG stereochemistry and their impact on cellular metabolism and signaling. Further, we describe intracellular DAG turnover and its stereochemistry in a 3-pool model to illustrate the spatial and stereochemical separation and hereby the diversity of cellular DAG metabolism.
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Affiliation(s)
- Thomas Oliver Eichmann
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31/2, 8010, Graz, Austria.
| | - Achim Lass
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31/2, 8010, Graz, Austria.
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70
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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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71
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Li C, Li L, Lian J, Watts R, Nelson R, Goodwin B, Lehner R. Roles of Acyl-CoA:Diacylglycerol Acyltransferases 1 and 2 in Triacylglycerol Synthesis and Secretion in Primary Hepatocytes. Arterioscler Thromb Vasc Biol 2015; 35:1080-91. [PMID: 25792450 DOI: 10.1161/atvbaha.114.304584] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 03/04/2015] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Very low-density lipoprotein assembly and secretion are regulated by the availability of triacylglycerol. Although compelling evidence indicates that the majority of triacylglycerol in very low-density lipoprotein is derived from re-esterification of lipolytic products released by endoplasmic reticulum-associated lipases, little is known about roles of acyl-CoA:diacylglycerol acyltransferases (DGATs) in this process. We aimed to investigate the contribution of DGAT1 and DGAT2 in lipid metabolism and lipoprotein secretion in primary mouse and human hepatocytes. APPROACH AND RESULTS We used highly selective small-molecule inhibitors of DGAT1 and DGAT2, and we tracked storage and secretion of lipids synthesized de novo from [(3)H]acetic acid and from exogenously supplied [(3)H]oleic acid. Inactivation of individual DGAT activity did not affect incorporation of either radiolabeled precursor into intracellular triacylglycerol, whereas combined inactivation of both DGATs severely attenuated triacylglycerol synthesis. However, inhibition of DGAT2 augmented fatty acid oxidation, whereas inhibition of DGAT1 increased triacylglycerol secretion, suggesting preferential channeling of separate DGAT-derived triacylglycerol pools to distinct metabolic pathways. Inactivation of DGAT2 impaired cytosolic lipid droplet expansion, whereas DGAT1 inactivation promoted large lipid droplet formation. Moreover, inactivation of DGAT2 attenuated expression of lipogenic genes. Finally, triacylglycerol secretion was significantly reduced on DGAT2 inhibition without altering extracellular apolipoprotein B levels. CONCLUSIONS Our data suggest that DGAT1 and DGAT2 can compensate for each other to synthesize triacylglycerol, but triacylglycerol synthesized by DGAT1 is preferentially channeled to oxidation, whereas DGAT2 synthesizes triacylglycerol destined for very low-density lipoprotein assembly.
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Affiliation(s)
- Chen Li
- From the Group on Molecular and Cell Biology of Lipids (C.L., L.L., J.L., R.W., R.N., R.L.), Department of Cell Biology (C.L., R.L.), Department of Pediatrics (L.L., J.L., R.W., R.N., R.L.), Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada; and Pfizer Global Research and Development, Cardiovascular and Metabolic Diseases Research Unit, Cambridge, MA (B.G.)
| | - Lena Li
- From the Group on Molecular and Cell Biology of Lipids (C.L., L.L., J.L., R.W., R.N., R.L.), Department of Cell Biology (C.L., R.L.), Department of Pediatrics (L.L., J.L., R.W., R.N., R.L.), Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada; and Pfizer Global Research and Development, Cardiovascular and Metabolic Diseases Research Unit, Cambridge, MA (B.G.)
| | - Jihong Lian
- From the Group on Molecular and Cell Biology of Lipids (C.L., L.L., J.L., R.W., R.N., R.L.), Department of Cell Biology (C.L., R.L.), Department of Pediatrics (L.L., J.L., R.W., R.N., R.L.), Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada; and Pfizer Global Research and Development, Cardiovascular and Metabolic Diseases Research Unit, Cambridge, MA (B.G.)
| | - Russell Watts
- From the Group on Molecular and Cell Biology of Lipids (C.L., L.L., J.L., R.W., R.N., R.L.), Department of Cell Biology (C.L., R.L.), Department of Pediatrics (L.L., J.L., R.W., R.N., R.L.), Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada; and Pfizer Global Research and Development, Cardiovascular and Metabolic Diseases Research Unit, Cambridge, MA (B.G.)
| | - Randal Nelson
- From the Group on Molecular and Cell Biology of Lipids (C.L., L.L., J.L., R.W., R.N., R.L.), Department of Cell Biology (C.L., R.L.), Department of Pediatrics (L.L., J.L., R.W., R.N., R.L.), Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada; and Pfizer Global Research and Development, Cardiovascular and Metabolic Diseases Research Unit, Cambridge, MA (B.G.)
| | - Bryan Goodwin
- From the Group on Molecular and Cell Biology of Lipids (C.L., L.L., J.L., R.W., R.N., R.L.), Department of Cell Biology (C.L., R.L.), Department of Pediatrics (L.L., J.L., R.W., R.N., R.L.), Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada; and Pfizer Global Research and Development, Cardiovascular and Metabolic Diseases Research Unit, Cambridge, MA (B.G.)
| | - Richard Lehner
- From the Group on Molecular and Cell Biology of Lipids (C.L., L.L., J.L., R.W., R.N., R.L.), Department of Cell Biology (C.L., R.L.), Department of Pediatrics (L.L., J.L., R.W., R.N., R.L.), Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada; and Pfizer Global Research and Development, Cardiovascular and Metabolic Diseases Research Unit, Cambridge, MA (B.G.).
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72
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da Silva RP, Kelly KB, Leonard KA, Jacobs RL. Creatine reduces hepatic TG accumulation in hepatocytes by stimulating fatty acid oxidation. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1639-46. [PMID: 25205520 DOI: 10.1016/j.bbalip.2014.09.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 08/15/2014] [Accepted: 09/02/2014] [Indexed: 12/22/2022]
Abstract
Non-alcoholic fatty liver disease encompasses a wide spectrum of liver damage including steatosis, non-alcoholic steatohepatitis, fibrosis and cirrhosis. We have previously reported that creatine supplementation prevents hepatic steatosis and lipid peroxidation in rats fed a high-fat diet. In this study, we employed oleate-treated McArdle RH-7777 rat hepatoma cells to investigate the role of creatine in regulating hepatic lipid metabolism. Creatine, but not structural analogs, reduced cellular TG accumulation in a dose-dependent manner. Incubating cells with the pan-lipase inhibitor diethyl p-nitrophenylphosphate (E600) did not diminish the effect of creatine, demonstrating that the TG reduction brought about by creatine does not depend on lipolysis. Radiolabeled tracer experiments indicate that creatine increases fatty acid oxidation and TG secretion. In line with increased fatty acid oxidation, mRNA analysis revealed that creatine-treated cells had increased expression of PPARα and several of its transcriptional targets. Taken together, this study provides direct evidence that creatine reduces lipid accumulation in hepatocytes by the stimulation of fatty acid oxidation and TG secretion.
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Affiliation(s)
- Robin P da Silva
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Karen B Kelly
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Kelly-Ann Leonard
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - René L Jacobs
- Metabolic and Cardiovascular Diseases Laboratory, Group on the Molecular and Cell Biology of Lipids, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
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73
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Kim MO, Lee S, Choi K, Lee S, Kim H, Kang H, Choi M, Kwon EB, Kang MJ, Kim S, Lee HJ, Lee HS, Kwak YS, Cho S. Discovery of a novel class of diacylglycerol acyltransferase 2 inhibitors with a 1H-pyrrolo[2,3-b]pyridine core. Biol Pharm Bull 2014; 37:1655-60. [PMID: 25099343 DOI: 10.1248/bpb.b14-00447] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Diacylglycerol acyltransferase 2 (DGAT2), which catalyzes the final step in triacylglycerol (TG) synthesis, is a key enzyme associated with hepatic steatosis and insulin resistance. Here, using an in vitro screen of 20000 molecules, we identified a class of compounds with a substituted 1H-pyrrolo[2,3-b]pyridine core which proved to be potent and selective inhibitors of human DGAT2. Of these compounds, H2-003 and -005 exhibited a considerable reduction in TG biosynthesis in HepG2 hepatic cells and 3T3-L1 preadipose cells. These compounds exert DGAT2-specific-inhibitory activity, which was further confirmed in DGAT2- or DGAT1-overexpressing HEK293 cells. In addition, these compounds almost completely abolished lipid droplet formation in 3T3-L1 cells when co-treated with a DGAT1 inhibitor, which was not attained using either a DGAT2 or DGAT1 inhibitor alone. Collectively, we identified two DGAT2 inhibitors, H2-003 and -005. These compounds will aid in DGAT2-related lipid metabolism research as well as in therapeutic development for the treatment of metabolic diseases associated with excessive TG.
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Affiliation(s)
- Mun Ock Kim
- Targeted Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology
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74
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Wilfling F, Haas JT, Walther TC, Farese RV. Lipid droplet biogenesis. Curr Opin Cell Biol 2014; 29:39-45. [PMID: 24736091 DOI: 10.1016/j.ceb.2014.03.008] [Citation(s) in RCA: 288] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 03/18/2014] [Accepted: 03/19/2014] [Indexed: 11/28/2022]
Abstract
Lipid droplets (LDs) are found in most cells, where they play central roles in energy and membrane lipid metabolism. The de novo biogenesis of LDs is a fascinating, yet poorly understood process involving the formation of a monolayer bound organelle from a bilayer membrane. Additionally, large LDs can form either by growth of existing LDs or by the combination of smaller LDs through several distinct mechanisms. Here, we review recent insights into the molecular process governing LD biogenesis and highlight areas of incomplete knowledge.
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Affiliation(s)
- Florian Wilfling
- Yale School of Medicine, Department of Cell Biology, New Haven, CT, USA
| | - Joel T Haas
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA, USA; Department of Biochemistry and Biophysics, University of California-San Francisco, CA, USA
| | - Tobias C Walther
- Yale School of Medicine, Department of Cell Biology, New Haven, CT, USA.
| | - Robert V Farese
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA, USA; Department of Biochemistry and Biophysics, University of California-San Francisco, CA, USA; Department of Medicine, University of California-San Francisco, CA, USA.
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75
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Fox BM, Sugimoto K, Iio K, Yoshida A, Zhang J(K, Li K, Hao X, Labelle M, Smith ML, Rubenstein SM, Ye G, McMinn D, Jackson S, Choi R, Shan B, Ma J, Miao S, Matsui T, Ogawa N, Suzuki M, Kobayashi A, Ozeki H, Okuma C, Ishii Y, Tomimoto D, Furakawa N, Tanaka M, Matsushita M, Takahashi M, Inaba T, Sagawa S, Kayser F. Discovery of 6-Phenylpyrimido[4,5-b][1,4]oxazines as Potent and Selective Acyl CoA:Diacylglycerol Acyltransferase 1 (DGAT1) Inhibitors with in Vivo Efficacy in Rodents. J Med Chem 2014; 57:3464-83. [DOI: 10.1021/jm500135c] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Brian M. Fox
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
| | - Kazuyuki Sugimoto
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Kiyosei Iio
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Atsuhito Yoshida
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Jian (Ken) Zhang
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
| | - Kexue Li
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
| | - Xiaolin Hao
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
| | - Marc Labelle
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
| | - Marie-Louise Smith
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
| | - Steven M. Rubenstein
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
| | - Guosen Ye
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
| | - Dustin McMinn
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
| | - Simon Jackson
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
| | - Rebekah Choi
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
| | - Bei Shan
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
| | - Ji Ma
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
| | - Shichang Miao
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
| | - Takuya Matsui
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Nobuya Ogawa
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Masahiro Suzuki
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Akio Kobayashi
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Hidekazu Ozeki
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Chihiro Okuma
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Yukihito Ishii
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Daisuke Tomimoto
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Noboru Furakawa
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Masahiro Tanaka
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Mutsuyoshi Matsushita
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Mitsuru Takahashi
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Takashi Inaba
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Shoichi Sagawa
- Central
Pharmaceutical
Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Frank Kayser
- Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
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76
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Sahini N, Borlak J. Recent insights into the molecular pathophysiology of lipid droplet formation in hepatocytes. Prog Lipid Res 2014; 54:86-112. [PMID: 24607340 DOI: 10.1016/j.plipres.2014.02.002] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 02/17/2014] [Accepted: 02/21/2014] [Indexed: 12/11/2022]
Abstract
Triacyglycerols are a major energy reserve of the body and are normally stored in adipose tissue as lipid droplets (LDs). The liver, however, stores energy as glycogen and digested triglycerides in the form of fatty acids. In stressed condition such as obesity, imbalanced nutrition and drug induced liver injury hepatocytes accumulate excess lipids in the form of LDs whose prolonged storage leads to disease conditions most notably non-alcoholic fatty liver disease (NAFLD). Fatty liver disease has become a major health burden with more than 90% of obese, nearly 70% of overweight and about 25% of normal weight patients being affected. Notably, research in recent years has shown LD as highly dynamic organelles for maintaining lipid homeostasis through fat storage, protein sorting and other molecular events studied in adipocytes and other cells of living organisms. This review focuses on the molecular events of LD formation in hepatocytes and the importance of cross talk between different cell types and their signalling in NAFLD as to provide a perspective on molecular mechanisms as well as possibilities for different therapeutic intervention strategies.
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Affiliation(s)
- Nishika Sahini
- Centre for Pharmacology and Toxicology, Hannover Medical School, 30625 Hannover, Germany
| | - Jürgen Borlak
- Centre for Pharmacology and Toxicology, Hannover Medical School, 30625 Hannover, Germany.
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77
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Linden MA, Fletcher JA, Morris EM, Meers GM, Kearney ML, Crissey JM, Laughlin MH, Booth FW, Sowers JR, Ibdah JA, Thyfault JP, Rector RS. Combining metformin and aerobic exercise training in the treatment of type 2 diabetes and NAFLD in OLETF rats. Am J Physiol Endocrinol Metab 2014; 306:E300-10. [PMID: 24326426 PMCID: PMC3920010 DOI: 10.1152/ajpendo.00427.2013] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Here, we sought to compare the efficacy of combining exercise and metformin for the treatment of type 2 diabetes and nonalcoholic fatty liver disease (NAFLD) in hyperphagic, obese, type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. OLETF rats (age: 20 wk, hyperglycemic and hyperinsulinemic; n = 10/group) were randomly assigned to sedentary (O-SED), SED plus metformin (O-SED + M; 300 mg·kg(-1)·day(-1)), moderate-intensity exercise training (O-EndEx; 20 m/min, 60 min/day, 5 days/wk treadmill running), or O-EndEx + M groups for 12 wk. Long-Evans Tokushima Otsuka (L-SED) rats served as nonhyperphagic controls. O-SED + M, O-EndEx, and O-EndEx + M were effective in the management of type 2 diabetes, and all three treatments lowered hepatic steatosis and serum markers of liver injury; however, O-EndEx lowered liver triglyceride content and fasting hyperglycemia more than O-SED + M. In addition, exercise elicited greater improvements compared with metformin alone on postchallenge glycemic control, liver diacylglycerol content, hepatic mitochondrial palmitate oxidation, citrate synthase, and β-HAD activities and in the attenuation of markers of hepatic fatty acid uptake and de novo fatty acid synthesis. Surprisingly, combining metformin and aerobic exercise training offered little added benefit to these outcomes, and in fact, metformin actually blunted exercise-induced increases in complete mitochondrial palmitate oxidation and β-HAD activity. In conclusion, aerobic exercise training was more effective than metformin administration in the management of type 2 diabetes and NAFLD outcomes in obese hyperphagic OLETF rats. Combining therapies offered little additional benefit beyond exercise alone, and findings suggest that metformin potentially impairs exercise-induced hepatic mitochondrial adaptations.
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Affiliation(s)
- Melissa A Linden
- Research Service, Harry S. Truman Memorial Veterans Affairs Hospital
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78
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Morris EM, Jackman MR, Meers GME, Johnson GC, Lopez JL, MacLean PS, Thyfault JP. Reduced hepatic mitochondrial respiration following acute high-fat diet is prevented by PGC-1α overexpression. Am J Physiol Gastrointest Liver Physiol 2013; 305:G868-80. [PMID: 24091599 PMCID: PMC3882433 DOI: 10.1152/ajpgi.00179.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Changes in substrate utilization and reduced mitochondrial respiratory capacity following exposure to energy-dense, high-fat diets (HFD) are putatively key components in the development of obesity-related metabolic disease. We examined the effect of a 3-day HFD on isolated liver mitochondrial respiration and whole body energy utilization in obesity-prone (OP) rats. We also examined if hepatic overexpression of peroxisomal proliferator-activated receptor-γ coactivator-1α (PGC-1α), a master regulator of mitochondrial respiratory capacity and biogenesis, would modify liver and whole body responses to the HFD. Acute, 3-day HFD (45% kcal) in OP rats resulted in increased daily energy intake, energy balance, weight gain, and adiposity, without an increase in liver triglyceride (triacylglycerol) accumulation. HFD-fed OP rats also displayed decreased whole body substrate switching from the dark to the light cycle, which was paired with reductions in hepatic mitochondrial respiration of multiple substrates in multiple respiratory states. Hepatic PGC-1α overexpression was observed to protect whole body substrate switching, as well as maintain mitochondrial respiration, following the acute HFD. Additionally, liver PGC-1α overexpression did not alter whole body dietary fatty acid oxidation but resulted in greater storage of dietary free fatty acids in liver lipid, primarily as triacylglycerol. Together, these data demonstrate that a short-term HFD can result in a decrease in metabolic flexibility and hepatic mitochondrial respiratory capacity in OP rats that is completely prevented by hepatic overexpression of PGC-1α.
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Affiliation(s)
- E. Matthew Morris
- 1Department of Internal Medicine-Gastroenterology, University of Missouri, Columbia, Missouri;
| | - Matthew R. Jackman
- 4Center for Human Nutrition, University of Colorado Denver, Denver, Colorado; ,6Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Colorado Denver, Denver, Colorado
| | - Grace M. E. Meers
- 1Department of Internal Medicine-Gastroenterology, University of Missouri, Columbia, Missouri;
| | - Ginger C. Johnson
- 4Center for Human Nutrition, University of Colorado Denver, Denver, Colorado; ,6Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Colorado Denver, Denver, Colorado
| | - Jordan L. Lopez
- 4Center for Human Nutrition, University of Colorado Denver, Denver, Colorado; ,6Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Colorado Denver, Denver, Colorado
| | - Paul S. MacLean
- 4Center for Human Nutrition, University of Colorado Denver, Denver, Colorado; ,5Department of Physiology and Biophysics, University of Colorado Denver, Denver, Colorado; and ,6Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Colorado Denver, Denver, Colorado
| | - John P. Thyfault
- 1Department of Internal Medicine-Gastroenterology, University of Missouri, Columbia, Missouri; ,2Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri; ,3Research Service, Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri;
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Clugston RD, Yuen JJ, Hu Y, Abumrad NA, Berk PD, Goldberg IJ, Blaner WS, Huang LS. CD36-deficient mice are resistant to alcohol- and high-carbohydrate-induced hepatic steatosis. J Lipid Res 2013; 55:239-46. [PMID: 24280415 DOI: 10.1194/jlr.m041863] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CD36 is a scavenger receptor with multiple ligands and cellular functions, including facilitating cellular uptake of free fatty acids (FFAs). Chronic alcohol consumption increases hepatic CD36 expression, leading to the hypothesis that this promotes uptake of circulating FFAs, which then serve as a substrate for triglyceride (TG) synthesis and the development of alcoholic steatosis. We investigated this hypothesis in alcohol-fed wild-type and Cd36-deficient (Cd36(-/-)) mice using low-fat/high-carbohydrate Lieber-DeCarli liquid diets, positing that Cd36(-/-) mice would be resistant to alcoholic steatosis. Our data show that the livers of Cd36(-/-) mice are resistant to the lipogenic effect of consuming high-carbohydrate liquid diets. These mice also do not further develop alcoholic steatosis when chronically fed alcohol. Surprisingly, we did not detect an effect of alcohol or CD36 deficiency on hepatic FFA uptake; however, the lower baseline levels of hepatic TG in Cd36(-/-) mice fed a liquid diet were associated with decreased expression of genes in the de novo lipogenesis pathway and a lower rate of hepatic de novo lipogenesis. In conclusion, Cd36(-/-) mice are resistant to hepatic steatosis when fed a high-carbohydrate liquid diet, and they are also resistant to alcoholic steatosis. These studies highlight an important role for CD36 in hepatic lipid homeostasis that is not associated with hepatic fatty acid uptake.
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80
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Abstract
The liver plays a unique, central role in regulating lipid metabolism. In addition to influencing hepatic function and disease, changes in specific pathways of fatty acid (FA) metabolism have wide-ranging effects on the metabolism of other nutrients, extra-hepatic physiology, and the development of metabolic diseases. The high prevalence of nonalcoholic fatty liver disease (NAFLD) has led to increased efforts to characterize the underlying biology of hepatic energy metabolism and FA trafficking that leads to disease development. Recent advances have uncovered novel roles of metabolic pathways and specific enzymes in generating lipids important for cellular processes such as signal transduction and transcriptional activation. These studies have also advanced our understanding of key branch points involving FA partitioning between metabolic pathways and have identified new roles for lipid droplets in these events. This review covers recent advances in our understanding of FA trafficking and its regulation. An emphasis will be placed on branch points in these pathways and how alterations in FA trafficking contribute to NAFLD and related comorbidities.
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81
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Wendel AA, Cooper DE, Ilkayeva OR, Muoio DM, Coleman RA. Glycerol-3-phosphate acyltransferase (GPAT)-1, but not GPAT4, incorporates newly synthesized fatty acids into triacylglycerol and diminishes fatty acid oxidation. J Biol Chem 2013; 288:27299-27306. [PMID: 23908354 DOI: 10.1074/jbc.m113.485219] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Four glycerol-3-phosphate acyltransferase (GPAT) isoforms, each encoded by a separate gene, catalyze the initial step in glycerolipid synthesis; in liver, the major isoforms are GPAT1 and GPAT4. To determine whether each of these hepatic isoforms performs a unique function in the metabolism of fatty acid, we measured the incorporation of de novo synthesized fatty acid or exogenous fatty acid into complex lipids in primary mouse hepatocytes from control, Gpat1(-/-), and Gpat4(-/-) mice. Although hepatocytes from each genotype incorporated a similar amount of exogenous fatty acid into triacylglycerol (TAG), only control and Gpat4(-/-) hepatocytes were able to incorporate de novo synthesized fatty acid into TAG. When compared with controls, Gpat1(-/-) hepatocytes oxidized twice as much exogenous fatty acid. To confirm these findings and to assess hepatic β-oxidation metabolites, we measured acylcarnitines in liver from mice after a 24-h fast and after a 24-h fast followed by 48 h of refeeding with a high sucrose diet to promote lipogenesis. Confirming the in vitro findings, the hepatic content of long-chain acylcarnitine in fasted Gpat1(-/-) mice was 3-fold higher than in controls. When compared with control and Gpat4(-/-) mice, after the fasting-refeeding protocol, Gpat1(-/-) hepatic TAG was depleted, and long-chain acylcarnitine content was 3.5-fold higher. Taken together, these data demonstrate that GPAT1, but not GPAT4, is required to incorporate de novo synthesized fatty acids into TAG and to divert them away from oxidation.
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Affiliation(s)
- Angela A Wendel
- Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Daniel E Cooper
- Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Olga R Ilkayeva
- Sarah W. Stedman Nutrition and Metabolism Center and Departments of Medicine and Pharmacology and Cancer Biology, Duke University, Durham, North Carolina 27704
| | - Deborah M Muoio
- Sarah W. Stedman Nutrition and Metabolism Center and Departments of Medicine and Pharmacology and Cancer Biology, Duke University, Durham, North Carolina 27704
| | - Rosalind A Coleman
- Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina 27599.
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82
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McLaren DG, Cardasis HL, Stout SJ, Wang SP, Mendoza V, Castro-Perez JM, Miller PL, Murphy BA, Cumiskey AM, Cleary MA, Johns DG, Previs SF, Roddy TP. Use of [13C18] oleic acid and mass isotopomer distribution analysis to study synthesis of plasma triglycerides in vivo: analytical and experimental considerations. Anal Chem 2013; 85:6287-94. [PMID: 23668715 DOI: 10.1021/ac400363k] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have previously reported on a liquid chromatography-mass spectrometry method to determine the disposition of [(13)C18]-oleic acid following intravenous and oral administration in vivo. This approach has enabled us to study a variety of aspects of lipid metabolism including a quantitative assessment of triglyceride synthesis. Here we present a more rigorous evaluation of the constraints imposed upon the analytical method in order to generate accurate data using this stable-isotope tracer approach along with more detail on relevant analytical figures of merit including limits of quantitation, precision, and accuracy. The use of mass isotopomer distribution analysis (MIDA) to quantify plasma triglyceride synthesis is specifically highlighted, and a re-evaluation of the underlying mathematics has enabled us to present a simplified series of equations. The derivation of this MIDA model and the significance of all underlying assumptions are explored in detail, and examples are given of how it can successfully be applied to detect differences in plasma triglyceride synthesis in lean and high-fat diet fed mouse models. More work is necessary to evaluate the applicability of this approach to triglyceride stores with slower rates of turnover such as in adipose or muscle tissue; however, the present report provides investigators with the tools necessary to conduct such studies.
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Affiliation(s)
- David G McLaren
- Merck Research Laboratories, Merck & Co., Inc., Kenilworth, New Jersey 07033, USA.
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83
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Previs SF, McLaren DG, Wang SP, Stout SJ, Zhou H, Herath K, Shah V, Miller PL, Wilsie L, Castro-Perez J, Johns DG, Cleary MA, Roddy TP. New methodologies for studying lipid synthesis and turnover: looking backwards to enable moving forwards. Biochim Biophys Acta Mol Basis Dis 2013; 1842:402-13. [PMID: 23707557 DOI: 10.1016/j.bbadis.2013.05.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 05/11/2013] [Accepted: 05/13/2013] [Indexed: 12/26/2022]
Abstract
Our ability to understand the pathogenesis of problems surrounding lipid accretion requires attention towards quantifying lipid kinetics. In addition, studies of metabolic flux should also help unravel mechanisms that lead to imbalances in inter-organ lipid trafficking which contribute to dyslipidemia and/or peripheral lipid accumulation (e.g. hepatic fat deposits). This review aims to outline the development and use of novel methods for studying lipid kinetics in vivo. Although our focus is directed towards some of the approaches that are currently reported in the literature, we include a discussion of the older literature in order to put "new" methods in better perspective and inform readers of valuable historical research. Presumably, future advances in understanding lipid dynamics will benefit from a careful consideration of the past efforts, where possible we have tried to identify seminal papers or those that provide clear data to emphasize essential points. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.
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Affiliation(s)
- Stephen F Previs
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA.
| | - David G McLaren
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Sheng-Ping Wang
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Steven J Stout
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Haihong Zhou
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Kithsiri Herath
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Vinit Shah
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Paul L Miller
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Larissa Wilsie
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Jose Castro-Perez
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Douglas G Johns
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Michele A Cleary
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | - Thomas P Roddy
- Molecular Biomarkers, Merck, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
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84
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Hepatic triacylglycerol synthesis and secretion: DGAT2 as the link between glycaemia and triglyceridaemia. Biochem J 2013; 451:1-12. [PMID: 23489367 DOI: 10.1042/bj20121689] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
lThe liver regulates both glycaemia and triglyceridaemia. Hyperglycaemia and hypertriglyceridaemia are both characteristic of (pre)diabetes. Recent observations on the specialised role of DGAT2 (diacylglycerol acyltransferase 2) in catalysing the de novo synthesis of triacylglycerols from newly synthesized fatty acids and nascent diacylglycerols identifies this enzyme as the link between the two. This places DGAT2 at the centre of carbohydrate-induced hypertriglyceridaemia and hepatic steatosis. This function is complemented, but not substituted for, by the ability of DGAT1 to rescue partial glycerides from complete hydrolysis. In peripheral tissues not normally considered to be lipogenic, synthesis of triacylglycerols may largely bypass DGAT2 except in hyperglycaemic/hyperinsulinaemic conditions, when induction of de novo fatty acid synthesis in these tissues may contribute towards increased triacylglycerol secretion (intestine) or insulin resistance (adipose tissue, and cardiac and skeletal muscle).
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85
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Hodson L, Fielding BA. Stearoyl-CoA desaturase: rogue or innocent bystander? Prog Lipid Res 2013; 52:15-42. [DOI: 10.1016/j.plipres.2012.08.002] [Citation(s) in RCA: 152] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 08/27/2012] [Accepted: 08/27/2012] [Indexed: 02/07/2023]
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86
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Lee K, Kim M, Lee B, Goo J, Kim J, Naik R, Seo JH, Kim MO, Byun Y, Song GY, Lee HS, Choi Y. Discovery of indolyl acrylamide derivatives as human diacylglycerol acyltransferase-2 selective inhibitors. Org Biomol Chem 2012; 11:849-58. [PMID: 23242135 DOI: 10.1039/c2ob27114a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of indolyl acrylamide derivatives was synthesized as potential diacylglycerol acyltransferase (DGAT) inhibitors. Furfurylamine containing indolyl acrylamide derivative 5h exhibited the most potent DGAT inhibitory activity using microsomes prepared from rat liver. Further evaluation against human DGAT-1 and DGAT-2 identified indolyl acrylamide analogues as selective inhibitors against human DGAT-2. In addition, the most potent compound 5h inhibited triglyceride synthesis dose-dependently in HepG2 cell lines.
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Affiliation(s)
- Kyeong Lee
- College of Pharmacy, Dongguk University-Seoul, Seoul 100-715, Korea
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87
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Liu Q, Siloto RMP, Lehner R, Stone SJ, Weselake RJ. Acyl-CoA:diacylglycerol acyltransferase: molecular biology, biochemistry and biotechnology. Prog Lipid Res 2012; 51:350-77. [PMID: 22705711 DOI: 10.1016/j.plipres.2012.06.001] [Citation(s) in RCA: 224] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Triacylglycerol (TG) is a storage lipid which serves as an energy reservoir and a source of signalling molecules and substrates for membrane biogenesis. TG is essential for many physiological processes and its metabolism is widely conserved in nature. Acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) catalyzes the final step in the sn-glycerol-3-phosphate pathway leading to TG. DGAT activity resides mainly in two distinct membrane bound polypeptides, known as DGAT1 and DGAT2 which have been identified in numerous organisms. In addition, a few other enzymes also hold DGAT activity, including the DGAT-related acyl-CoA:monoacylglycerol acyltransferases (MGAT). Progress on understanding structure/function in DGATs has been limited by the lack of detailed three-dimensional structural information due to the hydrophobic properties of theses enzymes and difficulties associated with purification. This review examines several aspects of DGAT and MGAT genes and enzymes, including current knowledge on their gene structure, expression pattern, biochemical properties, membrane topology, functional motifs and subcellular localization. Recent progress in probing structural and functional aspects of DGAT1 and DGAT2, using a combination of molecular and biochemical techniques, is emphasized. Biotechnological applications involving DGAT enzymes ranging from obesity therapeutics to oilseed engineering are also discussed.
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Affiliation(s)
- Qin Liu
- Agricultural Lipid Biotechnology Program, Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6H 2P5.
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