101
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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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102
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Neess D, Bek S, Engelsby H, Gallego SF, Færgeman NJ. Long-chain acyl-CoA esters in metabolism and signaling: Role of acyl-CoA binding proteins. Prog Lipid Res 2015; 59:1-25. [PMID: 25898985 DOI: 10.1016/j.plipres.2015.04.001] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/11/2015] [Accepted: 04/09/2015] [Indexed: 02/03/2023]
Abstract
Long-chain fatty acyl-CoA esters are key intermediates in numerous lipid metabolic pathways, and recognized as important cellular signaling molecules. The intracellular flux and regulatory properties of acyl-CoA esters have been proposed to be coordinated by acyl-CoA-binding domain containing proteins (ACBDs). The ACBDs, which comprise a highly conserved multigene family of intracellular lipid-binding proteins, are found in all eukaryotes and ubiquitously expressed in all metazoan tissues, with distinct expression patterns for individual ACBDs. The ACBDs are involved in numerous intracellular processes including fatty acid-, glycerolipid- and glycerophospholipid biosynthesis, β-oxidation, cellular differentiation and proliferation as well as in the regulation of numerous enzyme activities. Little is known about the specific roles of the ACBDs in the regulation of these processes, however, recent studies have gained further insights into their in vivo functions and provided further evidence for ACBD-specific functions in cellular signaling and lipid metabolic pathways. This review summarizes the structural and functional properties of the various ACBDs, with special emphasis on the function of ACBD1, commonly known as ACBP.
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Affiliation(s)
- Ditte Neess
- Villum Center for Bioanalytical Sciences, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Signe Bek
- Villum Center for Bioanalytical Sciences, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Hanne Engelsby
- Villum Center for Bioanalytical Sciences, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Sandra F Gallego
- Villum Center for Bioanalytical Sciences, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Nils J Færgeman
- Villum Center for Bioanalytical Sciences, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.
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103
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Ellis KL, Zhou Y, Beshansky JR, Ainehsazan E, Selker HP, Cupples LA, Huggins GS, Peter I. Genetic modifiers of response to glucose-insulin-potassium (GIK) infusion in acute coronary syndromes and associations with clinical outcomes in the IMMEDIATE trial. THE PHARMACOGENOMICS JOURNAL 2015; 15:488-95. [PMID: 25778467 DOI: 10.1038/tpj.2015.10] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 12/17/2014] [Accepted: 01/28/2015] [Indexed: 11/09/2022]
Abstract
Modifiers of response to glucose, insulin and potassium (GIK) infusion may affect clinical outcomes in acute coronary syndromes (ACS). In an Immediate Myocardial Metabolic Enhancement During Initial Assessment And Treatment In Emergency Care (IMMEDIATE) trial's sub-study (n = 318), we explored effects of 132,634 genetic variants on plasma glucose and potassium response to 12-h GIK infusion. Associations between metabolite-associated variants and infarct size (n = 84) were assessed. The 'G' allele of rs12641551, near ACSL1, as well as the 'A' allele of XPO4 rs2585897 were associated with a differential glucose response (P for 2 degrees of freedom test, P2df ⩽ 4.75 × 10(-7)) and infarct size with GIK (P2df < 0.05). Variants within or near TAS1R3, LCA5, DNAH5, PTPRG, MAGI1, PTCSC3, STRADA, AKAP12, ARFGEF2, ADCYAP1, SETX, NDRG4 and ABCB11 modified glucose response, and near CSF1/AHCYL1 potassium response (P2df ⩽ 4.26 × 10(-7)), but not outcomes. Gene variants may modify glucose and potassium response to GIK infusion, contributing to cardiovascular outcomes in ACS.
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Affiliation(s)
- K L Ellis
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Y Zhou
- Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA
| | - J R Beshansky
- Institute for Clinical Research and Health Policy Studies, Tufts Medical Center and Tufts University School of Medicine, Boston, MA, USA.,Regulatory and Clinical Research Management, Regis College, Weston, MA, USA
| | - E Ainehsazan
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - H P Selker
- Regulatory and Clinical Research Management, Regis College, Weston, MA, USA
| | - L A Cupples
- Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA
| | - G S Huggins
- Molecular Cardiology Research Institute Center for Translational Genomics, Tufts Medical Center, Boston, MA, USA
| | - I Peter
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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104
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Kundu BK, Zhong M, Sen S, Davogustto G, Keller SR, Taegtmeyer H. Remodeling of glucose metabolism precedes pressure overload-induced left ventricular hypertrophy: review of a hypothesis. Cardiology 2015; 130:211-20. [PMID: 25791172 DOI: 10.1159/000369782] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 11/10/2014] [Indexed: 12/14/2022]
Abstract
When subjected to pressure overload, the ventricular myocardium shifts from fatty acids to glucose as its main source for energy provision and frequently increases its mass. Here, we review the evidence in support of the concept that metabolic remodeling, measured as an increased myocardial glucose uptake using dynamic positron emission tomography (PET) with the glucose analogue 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG), precedes the onset of left ventricular hypertrophy (LVH) and heart failure. Consistent with this, early intervention with propranolol, which attenuates glucose uptake, prevents the maladaptive metabolic response and preserves cardiac function in vivo. We also review ex vivo studies suggesting a link between dysregulated myocardial glucose metabolism, intracellular accumulation of glucose 6-phosphate (G6P) and contractile dysfunction of the heart. G6P levels correlate with activation of mTOR (mechanistic target of rapamycin) and endoplasmic reticulum stress. This sequence of events could be prevented by pretreatment with rapamycin (mTOR inhibition) or metformin (enzyme 5'-AMP-activated protein kinase activation). In conclusion, we propose that metabolic imaging with FDG PET may provide a novel approach to guide the treatment of patients with hypertension-induced LVH.
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Affiliation(s)
- Bijoy K Kundu
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Va., USA
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105
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Abdurrachim D, Luiken JJFP, Nicolay K, Glatz JFC, Prompers JJ, Nabben M. Good and bad consequences of altered fatty acid metabolism in heart failure: evidence from mouse models. Cardiovasc Res 2015; 106:194-205. [PMID: 25765936 DOI: 10.1093/cvr/cvv105] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Accepted: 02/18/2015] [Indexed: 12/25/2022] Open
Abstract
The shift in substrate preference away from fatty acid oxidation (FAO) towards increased glucose utilization in heart failure has long been interpreted as an oxygen-sparing mechanism. Inhibition of FAO has therefore evolved as an accepted approach to treat heart failure. However, recent data indicate that increased reliance on glucose might be detrimental rather than beneficial for the failing heart. This review discusses new insights into metabolic adaptations in heart failure. A particular focus lies on data obtained from mouse models with modulations of cardiac FA metabolism at different levels of the FA metabolic pathway and how these differently affect cardiac function. Based on studies in which these mouse models were exposed to ischaemic and non-ischaemic heart failure, we discuss whether and when modulations in FA metabolism are protective against heart failure.
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Affiliation(s)
- Desiree Abdurrachim
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, High Tech Campus 11, 5656 AE, PO BOX 513, Eindhoven 5600 MB, The Netherlands
| | - Joost J F P Luiken
- Department of Genetics and Cell Biology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, High Tech Campus 11, 5656 AE, PO BOX 513, Eindhoven 5600 MB, The Netherlands
| | - Jan F C Glatz
- Department of Genetics and Cell Biology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Jeanine J Prompers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, High Tech Campus 11, 5656 AE, PO BOX 513, Eindhoven 5600 MB, The Netherlands
| | - Miranda Nabben
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, High Tech Campus 11, 5656 AE, PO BOX 513, Eindhoven 5600 MB, The Netherlands Department of Genetics and Cell Biology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
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106
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Ellis JM, Bowman CE, Wolfgang MJ. Metabolic and tissue-specific regulation of acyl-CoA metabolism. PLoS One 2015; 10:e0116587. [PMID: 25760036 PMCID: PMC4356623 DOI: 10.1371/journal.pone.0116587] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 12/11/2014] [Indexed: 01/22/2023] Open
Abstract
Acyl-CoA formation initiates cellular fatty acid metabolism. Acyl-CoAs are generated by the ligation of a fatty acid to Coenzyme A mediated by a large family of acyl-CoA synthetases (ACS). Conversely, acyl-CoAs can be hydrolyzed by a family of acyl-CoA thioesterases (ACOT). Here, we have determined the transcriptional regulation of all ACS and ACOT enzymes across tissues and in response to metabolic perturbations. We find patterns of coordinated regulation within and between these gene families as well as distinct regulation occurring in a tissue- and physiologically-dependent manner. Due to observed changes in long-chain ACOT mRNA and protein abundance in liver and adipose tissue, we determined the consequence of increasing cytosolic long-chain thioesterase activity on fatty acid metabolism in these tissues by generating transgenic mice overexpressing a hyperactive mutant of Acot7 in the liver or adipose tissue. Doubling cytosolic acyl-CoA thioesterase activity failed to protect mice from diet-induced obesity, fatty liver or insulin resistance, however, overexpression of Acot7 in adipocytes rendered mice cold intolerant. Together, these data suggest distinct modes of regulation of the ACS and ACOT enzymes and that these enzymes act in a coordinated fashion to control fatty acid metabolism in a tissue-dependent manner.
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Affiliation(s)
- Jessica M. Ellis
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Center for Metabolism and Obesity Research, Baltimore, Maryland 21205 United States of America
| | - Caitlyn E. Bowman
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Center for Metabolism and Obesity Research, Baltimore, Maryland 21205 United States of America
| | - Michael J. Wolfgang
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Center for Metabolism and Obesity Research, Baltimore, Maryland 21205 United States of America
- * E-mail:
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107
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Schisler JC, Grevengoed TJ, Pascual F, Cooper DE, Ellis JM, Paul DS, Willis MS, Patterson C, Jia W, Coleman RA. Cardiac energy dependence on glucose increases metabolites related to glutathione and activates metabolic genes controlled by mechanistic target of rapamycin. J Am Heart Assoc 2015; 4:jah3872. [PMID: 25713290 PMCID: PMC4345858 DOI: 10.1161/jaha.114.001136] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Background Long chain acyl‐CoA synthetases (ACSL) catalyze long‐chain fatty acids (FA) conversion to acyl‐CoAs. Temporal ACSL1 inactivation in mouse hearts (Acsl1H−/−) impaired FA oxidation and dramatically increased glucose uptake, glucose oxidation, and mTOR activation, resulting in cardiac hypertrophy. We used unbiased metabolomics and gene expression analyses to elucidate the cardiac cellular response to increased glucose use in a genetic model of inactivated FA oxidation. Methods and Results Metabolomics analysis identified 60 metabolites altered in Acsl1H−/− hearts, including 6 related to glucose metabolism and 11 to cysteine and glutathione pathways. Concurrently, global cardiac transcriptional analysis revealed differential expression of 568 genes in Acsl1H−/− hearts, a subset of which we hypothesized were targets of mTOR; subsequently, we measured the transcriptional response of several genes after chronic mTOR inhibition via rapamycin treatment during the period in which cardiac hypertrophy develops. Hearts from Acsl1H−/− mice increased expression of several Hif1α‐responsive glycolytic genes regulated by mTOR; additionally, expression of Scl7a5, Gsta1/2, Gdf15, and amino acid‐responsive genes, Fgf21, Asns, Trib3, Mthfd2, were strikingly increased by mTOR activation. Conclusions The switch from FA to glucose use causes mTOR‐dependent alterations in cardiac metabolism. We identified cardiac mTOR‐regulated genes not previously identified in other cellular models, suggesting heart‐specific mTOR signaling. Increased glucose use also changed glutathione‐related pathways and compensation by mTOR. The hypertrophy, oxidative stress, and metabolic changes that occur within the heart when glucose supplants FA as a major energy source suggest that substrate switching to glucose is not entirely benign.
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Affiliation(s)
- Jonathan C Schisler
- Division of Cardiology, Department of Medicine, University of North Carolina, Chapel Hill, NC (J.C.S., C.P.)
| | - Trisha J Grevengoed
- Department of Nutrition, University of North Carolina, Chapel Hill, NC (T.J.G., F.P., D.E.C., J.M.E., D.S.P., R.A.C.)
| | - Florencia Pascual
- Department of Nutrition, University of North Carolina, Chapel Hill, NC (T.J.G., F.P., D.E.C., J.M.E., D.S.P., R.A.C.)
| | - Daniel E Cooper
- Department of Nutrition, University of North Carolina, Chapel Hill, NC (T.J.G., F.P., D.E.C., J.M.E., D.S.P., R.A.C.)
| | - Jessica M Ellis
- Department of Nutrition, University of North Carolina, Chapel Hill, NC (T.J.G., F.P., D.E.C., J.M.E., D.S.P., R.A.C.)
| | - David S Paul
- Department of Nutrition, University of North Carolina, Chapel Hill, NC (T.J.G., F.P., D.E.C., J.M.E., D.S.P., R.A.C.)
| | - Monte S Willis
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC (M.S.W.)
| | - Cam Patterson
- Division of Cardiology, Department of Medicine, University of North Carolina, Chapel Hill, NC (J.C.S., C.P.)
| | - Wei Jia
- Nutrition Research Institute, Kannapolis, NC (W.J.)
| | - Rosalind A Coleman
- Department of Nutrition, University of North Carolina, Chapel Hill, NC (T.J.G., F.P., D.E.C., J.M.E., D.S.P., R.A.C.)
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108
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Lee J, Ellis JM, Wolfgang MJ. Adipose fatty acid oxidation is required for thermogenesis and potentiates oxidative stress-induced inflammation. Cell Rep 2015; 10:266-79. [PMID: 25578732 PMCID: PMC4359063 DOI: 10.1016/j.celrep.2014.12.023] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 11/04/2014] [Accepted: 12/11/2014] [Indexed: 12/30/2022] Open
Abstract
To understand the contribution of adipose tissue fatty acid oxidation to whole-body metabolism, we generated mice with an adipose-specific knockout of carnitine palmitoyltransferase 2 (CPT2(A-/-)), an obligate step in mitochondrial long-chain fatty acid oxidation. CPT2(A-/-) mice became hypothermic after an acute cold challenge, and CPT2(A-/-) brown adipose tissue (BAT) failed to upregulate thermogenic genes in response to agonist-induced stimulation. The adipose-specific loss of CPT2 resulted in diet-dependent changes in adiposity but did not result in changes in body weight on low- or high-fat diets. Additionally, CPT2(A-/-) mice had suppressed high-fat diet-induced oxidative stress and inflammation in visceral white adipose tissue (WAT); however, high-fat diet-induced glucose intolerance was not improved. These data show that fatty acid oxidation is required for cold-induced thermogenesis in BAT and high-fat diet-induced oxidative stress and inflammation in WAT.
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Affiliation(s)
- Jieun Lee
- Department of Biological Chemistry, Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jessica M Ellis
- Department of Biological Chemistry, Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Michael J Wolfgang
- Department of Biological Chemistry, Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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109
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Li LO, Grevengoed TJ, Paul DS, Ilkayeva O, Koves TR, Pascual F, Newgard CB, Muoio DM, Coleman RA. Compartmentalized acyl-CoA metabolism in skeletal muscle regulates systemic glucose homeostasis. Diabetes 2015; 64:23-35. [PMID: 25071025 PMCID: PMC4274800 DOI: 10.2337/db13-1070] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The impaired capacity of skeletal muscle to switch between the oxidation of fatty acid (FA) and glucose is linked to disordered metabolic homeostasis. To understand how muscle FA oxidation affects systemic glucose, we studied mice with a skeletal muscle-specific deficiency of long-chain acyl-CoA synthetase (ACSL)1. ACSL1 deficiency caused a 91% loss of ACSL-specific activity and a 60-85% decrease in muscle FA oxidation. Acsl1(M-/-) mice were more insulin sensitive, and, during an overnight fast, their respiratory exchange ratio was higher, indicating greater glucose use. During endurance exercise, Acsl1(M-/-) mice ran only 48% as far as controls. At the time that Acsl1(M-/-) mice were exhausted but control mice continued to run, liver and muscle glycogen and triacylglycerol stores were similar in both genotypes; however, plasma glucose concentrations in Acsl1(M-/-) mice were ∼40 mg/dL, whereas glucose concentrations in controls were ∼90 mg/dL. Excess use of glucose and the likely use of amino acids for fuel within muscle depleted glucose reserves and diminished substrate availability for hepatic gluconeogenesis. Surprisingly, the content of muscle acyl-CoA at exhaustion was markedly elevated, indicating that acyl-CoAs synthesized by other ACSL isoforms were not available for β-oxidation. This compartmentalization of acyl-CoAs resulted in both an excessive glucose requirement and severely compromised systemic glucose homeostasis.
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Affiliation(s)
- Lei O Li
- Department of Nutrition, University of North Carolina, Chapel Hill, NC
| | | | - David S Paul
- Department of Nutrition, University of North Carolina, Chapel Hill, NC
| | - Olga Ilkayeva
- Sarah W. Stedman Nutrition and Metabolism Center, and Departments of Medicine and Pharmacology and Cancer Biology, Duke University, Durham, NC
| | - Timothy R Koves
- Sarah W. Stedman Nutrition and Metabolism Center, and Departments of Medicine and Pharmacology and Cancer Biology, Duke University, Durham, NC
| | - Florencia Pascual
- Department of Nutrition, University of North Carolina, Chapel Hill, NC
| | - Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center, and Departments of Medicine and Pharmacology and Cancer Biology, Duke University, Durham, NC
| | - Deborah M Muoio
- Sarah W. Stedman Nutrition and Metabolism Center, and Departments of Medicine and Pharmacology and Cancer Biology, Duke University, Durham, NC
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110
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Dobrzyn P, Bednarski T, Dobrzyn A. Metabolic reprogramming of the heart through stearoyl-CoA desaturase. Prog Lipid Res 2015; 57:1-12. [DOI: 10.1016/j.plipres.2014.11.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 11/25/2014] [Accepted: 11/25/2014] [Indexed: 02/06/2023]
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111
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Deficiency of a lipid droplet protein, perilipin 5, suppresses myocardial lipid accumulation, thereby preventing type 1 diabetes-induced heart malfunction. Mol Cell Biol 2014; 34:2721-31. [PMID: 24820416 DOI: 10.1128/mcb.00133-14] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Lipid droplet (LD) is a ubiquitous organelle that stores triacylglycerol and other neutral lipids. Perilipin 5 (Plin5), a member of the perilipin protein family that is abundantly expressed in the heart, is essential to protect LDs from attack by lipases, including adipose triglyceride lipase. Plin5 controls heart metabolism and performance by maintaining LDs under physiological conditions. Aberrant lipid accumulation in the heart leads to organ malfunction, or cardiomyopathy. To elucidate the role of Plin5 in a metabolically disordered state and the mechanism of lipid-induced cardiomyopathy, we studied the effects of streptozotocin-induced type 1 diabetes in Plin5-knockout (KO) mice. In contrast to diabetic wild-type mice, diabetic Plin5-KO mice lacked detectable LDs in the heart and did not exhibit aberrant lipid accumulation, excessive reactive oxygen species (ROS) generation, or heart malfunction. Moreover, diabetic Plin5-KO mice exhibited lower heart levels of lipotoxic molecules, such as diacylglycerol and ceramide, than wild-type mice. Membrane translocation of protein kinase C and the assembly of NADPH oxidase 2 complex on the membrane were also suppressed. The results suggest that diabetic Plin5-KO mice are resistant to type 1 diabetes-induced heart malfunction due to the suppression of the diacylglycerol/ceramide-protein kinase C pathway and of excessive ROS generation by NADPH oxidase.
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112
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Taegtmeyer H, Lubrano G. Rethinking cardiac metabolism: metabolic cycles to refuel and rebuild the failing heart. F1000PRIME REPORTS 2014; 6:90. [PMID: 25374668 PMCID: PMC4191265 DOI: 10.12703/p6-90] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The heart is a self-renewing biological pump that converts chemical energy into mechanical energy. The entire process of energy conversion is subject to complex regulation at the transcriptional, translational and post-translational levels. Within this system, energy transfer occurs with high efficiency, facilitated by a series of compound-conserved cycles. At the same time, the constituent myocardial proteins themselves are continuously made and degraded in order to adjust to changes in energy demand and changes in the extracellular environment. We recently have identified signals arising from intermediary metabolism that regulate the cycle of myocardial protein turnover. Using a new conceptual framework, we discuss the principle of metabolic cycles and their importance for refueling and for rebuilding the failing heart.
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113
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Watanabe S, Horie T, Nagao K, Kuwabara Y, Baba O, Nishi H, Sowa N, Narazaki M, Matsuda T, Takemura G, Wada H, Hasegawa K, Kimura T, Ono K. Cardiac-specific inhibition of kinase activity in calcium/calmodulin-dependent protein kinase kinase-β leads to accelerated left ventricular remodeling and heart failure after transverse aortic constriction in mice. PLoS One 2014; 9:e108201. [PMID: 25255457 PMCID: PMC4177887 DOI: 10.1371/journal.pone.0108201] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 08/19/2014] [Indexed: 12/26/2022] Open
Abstract
Background The mechanism of cardiac energy production against sustained pressure overload remains to be elucidated. Methods and Results We generated cardiac-specific kinase-dead (kd) calcium/calmodulin-dependent protein kinase kinase-β (CaMKKβ) transgenic (α-MHC CaMKKβkd TG) mice using α-myosin heavy chain (α-MHC) promoter. Although CaMKKβ activity was significantly reduced, these mice had normal cardiac function and morphology at baseline. Here, we show that transverse aortic binding (TAC) in α-MHC CaMKKβkd TG mice led to accelerated death and left ventricular (LV) dilatation and dysfunction, which was accompanied by significant clinical signs of heart failure. CaMKKβ downstream signaling molecules, including adenosine monophosphate-activated protein kinase (AMPK), were also suppressed in α-MHC CaMKKβkd TG mice compared with wild-type (WT) mice. The expression levels of peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α, which is a downstream target of both of CaMKKβ and calcium/calmodulin kinases, were also significantly reduced in α-MHC CaMKKβkd TG mice compared with WT mice after TAC. In accordance with these findings, mitochondrial morphogenesis was damaged and creatine phosphate/β-ATP ratios assessed by magnetic resonance spectroscopy were suppressed in α-MHC CaMKKβkd TG mice compared with WT mice after TAC. Conclusions These data indicate that CaMKKβ exerts protective effects on cardiac adaptive energy pooling against pressure-overload possibly through phosphorylation of AMPK and by upregulation of PGC-1α. Thus, CaMKKβ may be a therapeutic target for the treatment of heart failure.
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Affiliation(s)
- Shin Watanabe
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takahiro Horie
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kazuya Nagao
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yasuhide Kuwabara
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Osamu Baba
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hitoo Nishi
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Naoya Sowa
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Michiko Narazaki
- Department of Systems Science, Graduate School of Informatics, Kyoto University, Kyoto, Japan
| | - Tetsuya Matsuda
- Department of Systems Science, Graduate School of Informatics, Kyoto University, Kyoto, Japan
| | - Genzou Takemura
- Department of Internal Medicine, Asahi University, Gifu, Japan
| | - Hiromichi Wada
- Division of Translational Research, Kyoto Medical Center, National Hospital Organization, Kyoto, Japan
| | - Koji Hasegawa
- Division of Translational Research, Kyoto Medical Center, National Hospital Organization, Kyoto, Japan
| | - Takeshi Kimura
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Koh Ono
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- * E-mail:
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114
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Abstract
The endothelium is often viewed solely as the barrier that prevents the penetration of circulating lipoproteins into the arterial wall. However, recent research has demonstrated that the endothelium has an important part in regulating circulating fatty acids and lipoproteins, and is in turn affected by these lipids/lipoproteins in ways that appear to have important repercussions for atherosclerosis. Thus, a number of potentially toxic lipids are produced during lipolysis of lipoproteins at the endothelial cell surface. Catabolism of triglyceride-rich lipoproteins creates free fatty acids that are readily taken up by endothelial cells, and, likely through the action of acyl-CoA synthetases, exacerbate inflammatory processes. In this article, we review how the endothelium participates in lipoprotein metabolism, how lipids alter endothelial functions, and how lipids are internalized, processed, and transported into the subendothelial space. Finally, we address the many endothelial changes that might promote atherogenesis, especially in the setting of diabetes.
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Affiliation(s)
- Ira J Goldberg
- Department of Medicine, Division of Preventive Medicine & Nutrition, Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY, 10032, USA,
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Carley AN, Taegtmeyer H, Lewandowski ED. Matrix revisited: mechanisms linking energy substrate metabolism to the function of the heart. Circ Res 2014; 114:717-29. [PMID: 24526677 DOI: 10.1161/circresaha.114.301863] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Metabolic signaling mechanisms are increasingly recognized to mediate the cellular response to alterations in workload demand, as a consequence of physiological and pathophysiological challenges. Thus, an understanding of the metabolic mechanisms coordinating activity in the cytosol with the energy-providing pathways in the mitochondrial matrix becomes critical for deepening our insights into the pathogenic changes that occur in the stressed cardiomyocyte. Processes that exchange both metabolic intermediates and cations between the cytosol and mitochondria enable transduction of dynamic changes in contractile state to the mitochondrial compartment of the cell. Disruption of such metabolic transduction pathways has severe consequences for the energetic support of contractile function in the heart and is implicated in the pathogenesis of heart failure. Deficiencies in metabolic reserve and impaired metabolic transduction in the cardiomyocyte can result from inherent deficiencies in metabolic phenotype or maladaptive changes in metabolic enzyme expression and regulation in the response to pathogenic stress. This review examines both current and emerging concepts of the functional linkage between the cytosol and the mitochondrial matrix with a specific focus on metabolic reserve and energetic efficiency. These principles of exchange and transport mechanisms across the mitochondrial membrane are reviewed for the failing heart from the perspectives of chronic pressure overload and diabetes mellitus.
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Affiliation(s)
- Andrew N Carley
- From the Center for Cardiovascular Research, University of Illinois at Chicago College of Medicine, Chicago IL (A.N.C., E.D.L.); and Department of Internal Medicine, Division of Cardiology, The University of Texas Medical School at Houston (H.T.)
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116
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Abstract
Long-chain fatty acyl-coenzyme As (CoAs) are critical regulatory molecules and metabolic intermediates. The initial step in their synthesis is the activation of fatty acids by one of 13 long-chain acyl-CoA synthetase isoforms. These isoforms are regulated independently and have different tissue expression patterns and subcellular locations. Their acyl-CoA products regulate metabolic enzymes and signaling pathways, become oxidized to provide cellular energy, and are incorporated into acylated proteins and complex lipids such as triacylglycerol, phospholipids, and cholesterol esters. Their differing metabolic fates are determined by a network of proteins that channel the acyl-CoAs toward or away from specific metabolic pathways and serve as the basis for partitioning. This review evaluates the evidence for acyl-CoA partitioning by reviewing experimental data on proteins that are believed to contribute to acyl-CoA channeling, the metabolic consequences of loss of these proteins, and the potential role of maladaptive acyl-CoA partitioning in the pathogenesis of metabolic disease and carcinogenesis.
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Barnes J, Pat B, Chen YW, Powell PC, Bradley WE, Zheng J, Karki A, Cui X, Guichard J, Wei CC, Collawn J, Dell'Italia LJ. Whole-genome profiling highlights the molecular complexity underlying eccentric cardiac hypertrophy. Ther Adv Cardiovasc Dis 2014; 8:97-118. [PMID: 24692245 DOI: 10.1177/1753944714527490] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVES Heart failure is typically preceded by myocardial hypertrophy and remodeling, which can be concentric due to pressure overload (PO), or eccentric because of volume overload (VO). The molecular mechanisms that underlie these differing patterns of hypertrophy are distinct and have yet to be fully elucidated. Thus, the goal of this work is to identify novel therapeutic targets for cardiovascular conditions marked by hypertrophy that have previously been resistant to medical treatment, such as a pure VO. METHODS Concentric or eccentric hypertrophy was induced in rats for 2 weeks with transverse aortic constriction (TAC) or aortocaval fistula (ACF), respectively. Hemodynamic and echocardiographic analysis were used to assess the development of left ventricular (LV) hypertrophy and functional differences between groups. Changes in gene expression were determined by microarray and further characterized with Ingenuity Pathway Analysis. RESULTS Both models of hypertrophy increased LV mass. Rats with TAC demonstrated concentric LV remodeling while rats with ACF exhibited eccentric LV remodeling. Microarray analysis associated eccentric remodeling with a more extensive alteration of gene expression compared with concentric remodeling. Rats with VO had a marked activation of extracellular matrix genes, promotion of cell cycle genes, downregulation of genes associated with oxidative metabolism, and dysregulation of genes critical to cardiac contractile function. Rats with PO demonstrated similar categorical changes, but with the involvement of fewer individual genes. CONCLUSIONS Our results indicate that eccentric remodeling is a far more complex process than concentric remodeling. This study highlights the importance of several key biological functions early in the course of VO, including regulation of matrix, metabolism, cell proliferation, and contractile function. Thus, the results of this analysis will inform the ongoing search for new treatments to prevent the progression to heart failure in VO.
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Affiliation(s)
- Justin Barnes
- Department of Pathology, Division of Molecular and Cellular Pathology, University of Alabama at Birmingham, Birmingham, Alabama, USADepartment of Medicine, Division of Cardiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Betty Pat
- Department of Medicine, Division of Cardiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Yuan-Wen Chen
- Department of Medicine, Division of Cardiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Pamela C Powell
- Department of Medicine, Division of Cardiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Wayne E Bradley
- Department of Medicine, Division of Cardiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Junying Zheng
- Department of Medicine, Division of Cardiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Amrit Karki
- Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Xiangqin Cui
- Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jason Guichard
- Department of Medicine, Division of Cardiology, University of Alabama at Birmingham, Birmingham, Alabama, USADepartment of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Chih-Chang Wei
- Birmingham Department of Veteran Affairs, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - James Collawn
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Paul DS, Grevengoed TJ, Pascual F, Ellis JM, Willis MS, Coleman RA. Deficiency of cardiac Acyl-CoA synthetase-1 induces diastolic dysfunction, but pathologic hypertrophy is reversed by rapamycin. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:880-7. [PMID: 24631848 DOI: 10.1016/j.bbalip.2014.03.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 02/17/2014] [Accepted: 03/03/2014] [Indexed: 12/14/2022]
Abstract
In mice with temporally-induced cardiac-specific deficiency of acyl-CoA synthetase-1 (Acsl1(H-/-)), the heart is unable to oxidize long-chain fatty acids and relies primarily on glucose for energy. These metabolic changes result in the development of both a spontaneous cardiac hypertrophy and increased phosphorylated S6 kinase (S6K), a substrate of the mechanistic target of rapamycin, mTOR. Doppler echocardiography revealed evidence of significant diastolic dysfunction, indicated by a reduced E/A ratio and increased mean performance index, although the deceleration time and the expression of sarco/endoplasmic reticulum calcium ATPase and phospholamban showed no difference between genotypes. To determine the role of mTOR in the development of cardiac hypertrophy, we treated Acsl1(H-/-) mice with rapamycin. Six to eight week old Acsl1(H-/-) mice and their littermate controls were given i.p. tamoxifen to eliminate cardiac Acsl1, then concomitantly treated for 10weeks with i.p. rapamycin or vehicle alone. Rapamycin completely blocked the enhanced ventricular S6K phosphorylation and cardiac hypertrophy and attenuated the expression of hypertrophy-associated fetal genes, including α-skeletal actin and B-type natriuretic peptide. mTOR activation of the related Acsl3 gene, usually associated with pathologic hypertrophy, was also attenuated in the Acsl1(H-/-) hearts, indicating that alternative pathways of fatty acid activation did not compensate for the loss of Acsl1. Compared to controls, Acsl1(H-/-) hearts exhibited an 8-fold higher uptake of 2-deoxy[1-(14)C]glucose and a 35% lower uptake of the fatty acid analog 2-bromo[1-(14)C]palmitate. These data indicate that Acsl1-deficiency causes diastolic dysfunction and that mTOR activation is linked to the development of cardiac hypertrophy in Acsl1(H-/-) mice.
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Affiliation(s)
- David S Paul
- McAllister Heart Institute, University of NC at Chapel Hill, 27599, USA.
| | | | - Florencia Pascual
- Department of Nutrition, University of NC at Chapel Hill, 27599, USA.
| | - Jessica M Ellis
- Department of Nutrition, University of NC at Chapel Hill, 27599, USA.
| | - Monte S Willis
- McAllister Heart Institute, University of NC at Chapel Hill, 27599, USA; Department of Pathology and Laboratory Medicine, University of NC at Chapel Hill, 27599, USA.
| | - Rosalind A Coleman
- Department of Nutrition, University of NC at Chapel Hill, 27599, USA; McAllister Heart Institute, University of NC at Chapel Hill, 27599, USA.
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Khan S, Abu Jawdeh BG, Goel M, Schilling WP, Parker MD, Puchowicz MA, Yadav SP, Harris RC, El-Meanawy A, Hoshi M, Shinlapawittayatorn K, Deschênes I, Ficker E, Schelling JR. Lipotoxic disruption of NHE1 interaction with PI(4,5)P2 expedites proximal tubule apoptosis. J Clin Invest 2014; 124:1057-68. [PMID: 24531551 DOI: 10.1172/jci71863] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 12/11/2013] [Indexed: 12/12/2022] Open
Abstract
Chronic kidney disease progression can be predicted based on the degree of tubular atrophy, which is the result of proximal tubule apoptosis. The Na+/H+ exchanger NHE1 regulates proximal tubule cell survival through interaction with phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], but pathophysiologic triggers for NHE1 inactivation are unknown. Because glomerular injury permits proximal tubule luminal exposure and reabsorption of fatty acid/albumin complexes, we hypothesized that accumulation of amphipathic, long-chain acyl-CoA (LC-CoA) metabolites stimulates lipoapoptosis by competing with the structurally similar PI(4,5)P2 for NHE1 binding. Kidneys from mouse models of progressive, albuminuric kidney disease exhibited increased fatty acids, LC-CoAs, and caspase-2-dependent proximal tubule lipoapoptosis. LC-CoAs and the cytosolic domain of NHE1 directly interacted, with an affinity comparable to that of the PI(4,5)P2-NHE1 interaction, and competing LC-CoAs disrupted binding of the NHE1 cytosolic tail to PI(4,5)P2. Inhibition of LC-CoA catabolism reduced NHE1 activity and enhanced apoptosis, whereas inhibition of proximal tubule LC-CoA generation preserved NHE1 activity and protected against apoptosis. Our data indicate that albuminuria/lipiduria enhances lipotoxin delivery to the proximal tubule and accumulation of LC-CoAs contributes to tubular atrophy by severing the NHE1-PI(4,5)P2 interaction, thereby lowering the apoptotic threshold. Furthermore, these data suggest that NHE1 functions as a metabolic sensor for lipotoxicity.
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Role of long-chain acyl-coenzyme A synthetases in the regulation of arachidonic acid metabolism in interleukin 1β-stimulated rat fibroblasts. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:44-53. [DOI: 10.1016/j.bbalip.2013.09.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 09/19/2013] [Accepted: 09/23/2013] [Indexed: 11/17/2022]
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Klaus C, Jeon MK, Kaemmerer E, Gassler N. Intestinal acyl-CoA synthetase 5: Activation of long chain fatty acids and behind. World J Gastroenterol 2013; 19:7369-7373. [PMID: 24259967 PMCID: PMC3831218 DOI: 10.3748/wjg.v19.i42.7369] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 09/29/2013] [Indexed: 02/06/2023] Open
Abstract
The intestinal mucosa is characterized by a high complexity in terms of structure and functions and allows for a controlled demarcation towards the gut lumen. On the one hand it is responsible for pulping and selective absorption of alimentary substances ensuring the immunological tolerance, on the other hand it prevents the penetration of micro-organisms as well as bacterial outgrowth. The continuous regeneration of surface epithelia along the crypt-villus-axis in the small intestine is crucial to assuring these various functions. The core phenomena of intestinal epithelia regeneration comprise cell proliferation, migration, differentiation, and apoptosis. These partly contrarily oriented processes are molecularly balanced through numerous interacting signaling pathways like Wnt/β-catenin, Notch and Hedgehog, and regulated by various modifying factors. One of these modifiers is acyl-CoA synthetase 5 (ACSL5). It plays a key role in de novo lipid synthesis, fatty acid degradation and membrane modifications, and regulates several intestinal processes, primarily through different variants of protein lipidation, e.g., palmitoylation. ACSL5 was shown to interact with proapoptotic molecules, and besides seems to inhibit proliferation along the crypt-villus-axis. Because of its proapoptotic and antiproliferative characteristics it could be of significant relevance for intestinal homeostasis, cellular disorder and tumor development.
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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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Beloukas AI, Magiorkinis E, Tsoumakas TL, Kosma AG, Diamantis A. Milestones in the History of Research on Cardiac Energy Metabolism. Can J Cardiol 2013; 29:1504-11. [DOI: 10.1016/j.cjca.2012.10.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 10/03/2012] [Accepted: 10/09/2012] [Indexed: 12/21/2022] Open
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Nagendran J, Pulinilkunnil T, Kienesberger PC, Sung MM, Fung D, Febbraio M, Dyck JRB. Cardiomyocyte-specific ablation of CD36 improves post-ischemic functional recovery. J Mol Cell Cardiol 2013; 63:180-8. [PMID: 23948483 DOI: 10.1016/j.yjmcc.2013.07.020] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 07/29/2013] [Accepted: 07/31/2013] [Indexed: 12/19/2022]
Abstract
Although pre-clinical evidence has suggested that partial inhibition of myocardial fatty acid oxidation (FAO) and subsequent switch to greater glucose oxidation for ATP production can prevent ischemia/reperfusion injury, controversy about this approach persists. For example, mice with germline deletion of the FA transporter CD36, exhibited either impaired or unchanged post-ischemic functional recovery despite a 40-60% reduction in FAO rates. Because there are limitations to cardiac studies utilizing whole body CD36 knockout (totalCD36KO) mice, we have now generated an inducible and cardiomyocyte-specific CD36 KO (icCD36KO) mouse to better address the role of cardiomyocyte CD36 and its regulation of FAO and post-ischemic functional recovery. Four to six weeks following CD36 ablation, hearts from icCD36KO mice had significantly decreased FA uptake compared to controls, which was paralleled by significant reductions in intramyocardial triacylglycerol content. Analysis of cardiac energy metabolism using ex vivo working heart perfusions showed that reduced FAO rates were compensated by enhanced glucose oxidation in the hearts from icCD36KO mice. In contrast to the totalCD36KO mice, hearts from icCD36KO mice exhibited significantly improved functional recovery following ischemia/reperfusion (18min of global no-flow ischemia followed by 40min of aerobic reperfusion). This improved recovery was associated with lower calculated proton production prior to and following ischemia compared to controls. Moreover, the amount of ATP generated relative to cardiac work was significantly lower in the hearts from icCD36KO mice compared to controls, indicating significantly increased cardiac efficiency in the hearts from icCD36KO mice. These data provide genetic evidence that reduced FAO as a result of diminished CD36-mediated FA uptake improves post-ischemic cardiac efficiency and functional recovery. As such, targeting cardiomyocyte FA uptake and FAO via inhibition of CD36 in the adult myocardium may provide therapeutic benefit during ischemia-reperfusion.
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Affiliation(s)
- Jeevan Nagendran
- Cardiovascular Research Centre, Department of Pediatrics, Mazankowski Alberta Heart Institute, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; Division of Cardiac Surgery, Department of Surgery, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada
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Dobrzyn P, Pyrkowska A, Duda MK, Bednarski T, Maczewski M, Langfort J, Dobrzyn A. Expression of lipogenic genes is upregulated in the heart with exercise training-induced but not pressure overload-induced left ventricular hypertrophy. Am J Physiol Endocrinol Metab 2013; 304:E1348-58. [PMID: 23632628 DOI: 10.1152/ajpendo.00603.2012] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac hypertrophy is accompanied by molecular remodeling that affects different cellular pathways, including fatty acid (FA) utilization. In the present study, we show that cardiac lipid metabolism is differentially regulated in response to physiological (endurance training) and pathological [abdominal aortic banding (AAB)] hypertrophic stimuli. Physiological hypertrophy was accompanied by an increased expression of lipogenic genes and the activation of sterol regulatory element-binding protein-1c and Akt signaling. Additionally, FA oxidation pathways regulated by AMP-activated protein kinase (AMPK) and peroxisome proliferator activated receptor-α (PPARα) were induced in trained hearts. Cardiac lipid content was not changed by physiological stimulation, underlining balanced lipid utilization in the trained heart. Moreover, pathological hypertrophy induced the AMPK-regulated oxidative pathway, whereas PPARα and expression of its downstream targets, i.e., acyl-CoA oxidase and carnitine palmitoyltransferase I, were not affected by AAB. In contrast, pathological hypertrophy leads to cardiac triglyceride (TG) and diacylglycerol (DAG) accumulation, although the expression of lipogenic genes and the levels of FA transport proteins (CD36 and FATP) were not changed or reduced compared with the sham group. A possible explanation for this phenomenon is a decrease in lipolysis, as evidenced by the increased content of adipose triglyceride lipase inhibitor G0S2, the increased phosphorylation of hormone-sensitive lipase at Ser(565), and the decreased protein levels of DAG lipase that attenuate TG and DAG contents. The increased TG and DAG accumulation observed in AAB-induced hypertrophy might have lipotoxic effects, thereby predisposing to cardiomyopathy and heart failure in the future.
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Affiliation(s)
- Pawel Dobrzyn
- Laboratory of Molecular and Medical Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
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Klett EL, Chen S, Edin ML, Li LO, Ilkayeva O, Zeldin DC, Newgard CB, Coleman RA. Diminished acyl-CoA synthetase isoform 4 activity in INS 832/13 cells reduces cellular epoxyeicosatrienoic acid levels and results in impaired glucose-stimulated insulin secretion. J Biol Chem 2013; 288:21618-29. [PMID: 23766516 DOI: 10.1074/jbc.m113.481077] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glucose-stimulated insulin secretion (GSIS) in pancreatic beta-cells is potentiated by fatty acids (FA). The initial step in the metabolism of intracellular FA is the conversion to acyl-CoA by long chain acyl-CoA synthetases (Acsls). Because the predominantly expressed Acsl isoforms in INS 832/13 cells are Acsl4 and -5, we characterized the role of these Acsls in beta-cell function by using siRNA to knock down Acsl4 or Acsl5. Compared with control cells, an 80% suppression of Acsl4 decreased GSIS and FA-potentiated GSIS by 32 and 54%, respectively. Knockdown of Acsl5 did not alter GSIS. Acsl4 knockdown did not alter FA oxidation or long chain acyl-CoA levels. With Acsl4 knockdown, incubation with 17 mm glucose increased media epoxyeicosatrienoic acids (EETs) and reduced cell membrane levels of EETs. Further, exogenous EETs reduced GSIS in INS 832/13 cells, and in Acsl4 knockdown cells, an EET receptor antagonist partially rescued GSIS. These results strongly suggest that Acsl4 activates EETs to form EET-CoAs that are incorporated into glycerophospholipids, thereby sequestering EETs. Exposing INS 832/13 cells to arachidonate or linoleate reduced Acsl4 mRNA and protein expression and reduced GSIS. These data indicate that Acsl4 modulates GSIS by regulating the levels of unesterified EETs and that arachidonate controls the expression of its activator Acsl4.
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Affiliation(s)
- Eric L Klett
- Department of Medicine, Division of Endocrinology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7172, USA.
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Sen S, Kundu BK, Wu HCJ, Hashmi SS, Guthrie P, Locke LW, Roy RJ, Matherne GP, Berr SS, Terwelp M, Scott B, Carranza S, Frazier OH, Glover DK, Dillmann WH, Gambello MJ, Entman ML, Taegtmeyer H. Glucose regulation of load-induced mTOR signaling and ER stress in mammalian heart. J Am Heart Assoc 2013; 2:e004796. [PMID: 23686371 PMCID: PMC3698799 DOI: 10.1161/jaha.113.004796] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Changes in energy substrate metabolism are first responders to hemodynamic stress in the heart. We have previously shown that hexose-6-phosphate levels regulate mammalian target of rapamycin (mTOR) activation in response to insulin. We now tested the hypothesis that inotropic stimulation and increased afterload also regulate mTOR activation via glucose 6-phosphate (G6P) accumulation. METHODS AND RESULTS We subjected the working rat heart ex vivo to a high workload in the presence of different energy-providing substrates including glucose, glucose analogues, and noncarbohydrate substrates. We observed an association between G6P accumulation, mTOR activation, endoplasmic reticulum (ER) stress, and impaired contractile function, all of which were prevented by pretreating animals with rapamycin (mTOR inhibition) or metformin (AMPK activation). The histone deacetylase inhibitor 4-phenylbutyrate, which relieves ER stress, also improved contractile function. In contrast, adding the glucose analogue 2-deoxy-d-glucose, which is phosphorylated but not further metabolized, to the perfusate resulted in mTOR activation and contractile dysfunction. Next we tested our hypothesis in vivo by transverse aortic constriction in mice. Using a micro-PET system, we observed enhanced glucose tracer analog uptake and contractile dysfunction preceding dilatation of the left ventricle. In contrast, in hearts overexpressing SERCA2a, ER stress was reduced and contractile function was preserved with hypertrophy. Finally, we examined failing human hearts and found that mechanical unloading decreased G6P levels and ER stress markers. CONCLUSIONS We propose that glucose metabolic changes precede and regulate functional (and possibly also structural) remodeling of the heart. We implicate a critical role for G6P in load-induced mTOR activation and ER stress.
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Affiliation(s)
- Shiraj Sen
- Division of Cardiology, Department of Internal Medicine, The University of Texas Medical School at Houston, Houston, TX 77030, USA
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Kanter JE, Bornfeldt KE. Inflammation and diabetes-accelerated atherosclerosis: myeloid cell mediators. Trends Endocrinol Metab 2013; 24:137-44. [PMID: 23153419 PMCID: PMC3578033 DOI: 10.1016/j.tem.2012.10.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 10/12/2012] [Accepted: 10/15/2012] [Indexed: 12/29/2022]
Abstract
Monocytes and macrophages respond to and govern inflammation by producing a plethora of inflammatory modulators, including cytokines, chemokines, and arachidonic acid (C20:4)-derived lipid mediators. One of the most prevalent inflammatory diseases is cardiovascular disease, caused by atherosclerosis, and accelerated by diabetes. Recent research has demonstrated that monocytes/macrophages from diabetic mice and humans with type 1 diabetes show upregulation of the enzyme, acyl-CoA synthetase 1 (ACSL1), which promotes C20:4 metabolism, and that ACSL1 inhibition selectively protects these cells from the inflammatory and proatherosclerotic effects of diabetes, in mice. Increased understanding of the role of ACSL1 and other culprits in monocytes/macrophages in inflammation and diabetes-accelerated atherosclerosis offers hope for new treatment strategies to combat diabetic vascular disease.
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Affiliation(s)
- Jenny E Kanter
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA 98109, USA
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Nagendran J, Waller TJ, Dyck JRB. AMPK signalling and the control of substrate use in the heart. Mol Cell Endocrinol 2013; 366:180-93. [PMID: 22750050 DOI: 10.1016/j.mce.2012.06.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 03/29/2012] [Accepted: 06/21/2012] [Indexed: 12/21/2022]
Abstract
All mammalian cells rely on adenosine triphosphate (ATP) to maintain function and for survival. The heart has the highest basal ATP demand of any organ due to the necessity for continuous contraction. As such, the ability of the cardiomyocyte to monitor cellular energy status and adapt the supply of substrates to match the energy demand is crucial. One important serine/threonine protein kinase that monitors cellular energy status in the heart is adenosine monophosphate activated protein kinase (AMPK). AMPK is also a key enzyme that controls multiple catabolic and anabolic biochemical pathways in the heart and indirectly plays a crucial role in regulating cardiac function in both physiological and pathophysiological conditions. Herein, we review the involvement of AMPK in myocardial fatty acid and glucose transport and utilization, as it relates to basal cardiac function. We also assess the literature amassed on cardiac AMPK and discuss the controversies surrounding the role of AMPK in physiological and pathophysiological processes in the heart. The work reviewed herein also emphasizes areas that require further investigation for the purpose of eventually translating this information into improved patient care.
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Affiliation(s)
- Jeevan Nagendran
- Cardiovascular Research Centre, Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
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130
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Rubinow KB, Wall VZ, Nelson J, Mar D, Bomsztyk K, Askari B, Lai MA, Smith KD, Han MS, Vivekanandan-Giri A, Pennathur S, Albert CJ, Ford DA, Davis RJ, Bornfeldt KE. Acyl-CoA synthetase 1 is induced by Gram-negative bacteria and lipopolysaccharide and is required for phospholipid turnover in stimulated macrophages. J Biol Chem 2013; 288:9957-9970. [PMID: 23426369 DOI: 10.1074/jbc.m113.458372] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The enzyme acyl-CoA synthetase 1 (ACSL1) is induced by peroxisome proliferator-activated receptor α (PPARα) and PPARγ in insulin target tissues, such as skeletal muscle and adipose tissue, and plays an important role in β-oxidation in these tissues. In macrophages, however, ACSL1 mediates inflammatory effects without significant effects on β-oxidation. Thus, the function of ACSL1 varies in different tissues. We therefore investigated the signals and signal transduction pathways resulting in ACSL1 induction in macrophages as well as the consequences of ACSL1 deficiency for phospholipid turnover in LPS-activated macrophages. LPS, Gram-negative bacteria, IFN-γ, and TNFα all induce ACSL1 expression in macrophages, whereas PPAR agonists do not. LPS-induced ACSL1 expression is dependent on Toll-like receptor 4 (TLR4) and its adaptor protein TRIF (Toll-like receptor adaptor molecule 1) but does not require the MyD88 (myeloid differentiation primary response gene 88) arm of TLR4 signaling; nor does it require STAT1 (signal transducer and activator of transcription 1) for maximal induction. Furthermore, ACSL1 deletion attenuates phospholipid turnover in LPS-stimulated macrophages. Thus, the regulation and biological function of ACSL1 in macrophages differ markedly from that in insulin target tissues. These results suggest that ACSL1 may have an important role in the innate immune response. Further, these findings illustrate an interesting paradigm in which the same enzyme, ACSL1, confers distinct biological effects in different cell types, and these disparate functions are paralleled by differences in the pathways that regulate its expression.
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Affiliation(s)
- Katya B Rubinow
- Diabetes and Obesity Center of Excellence, Departments of Medicine, University of Washington, Seattle, Washington 98109
| | - Valerie Z Wall
- Diabetes and Obesity Center of Excellence, Departments of Medicine, University of Washington, Seattle, Washington 98109
| | - Joel Nelson
- Diabetes and Obesity Center of Excellence, Departments of Medicine, University of Washington, Seattle, Washington 98109
| | - Daniel Mar
- Diabetes and Obesity Center of Excellence, Departments of Medicine, University of Washington, Seattle, Washington 98109
| | - Karol Bomsztyk
- Diabetes and Obesity Center of Excellence, Departments of Medicine, University of Washington, Seattle, Washington 98109
| | - Bardia Askari
- Diabetes and Obesity Center of Excellence, Departments of Pathology, University of Washington, Seattle, Washington 98109
| | - Marvin A Lai
- Diabetes and Obesity Center of Excellence, Departments of Pathology, University of Washington, Seattle, Washington 98109
| | - Kelly D Smith
- Diabetes and Obesity Center of Excellence, Departments of Pathology, University of Washington, Seattle, Washington 98109
| | - Myoung Sook Han
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | | | | | - Carolyn J Albert
- Department of Biochemistry and Molecular Biology and Center for Cardiovascular Research, Saint Louis University School of Medicine, St. Louis, Missouri 63104
| | - David A Ford
- Department of Biochemistry and Molecular Biology and Center for Cardiovascular Research, Saint Louis University School of Medicine, St. Louis, Missouri 63104
| | - Roger J Davis
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Karin E Bornfeldt
- Diabetes and Obesity Center of Excellence, Departments of Medicine, University of Washington, Seattle, Washington 98109; Diabetes and Obesity Center of Excellence, Departments of Pathology, University of Washington, Seattle, Washington 98109.
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131
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Dong B, Kan CFK, Singh AB, Liu J. High-fructose diet downregulates long-chain acyl-CoA synthetase 3 expression in liver of hamsters via impairing LXR/RXR signaling pathway. J Lipid Res 2013; 54:1241-54. [PMID: 23427282 DOI: 10.1194/jlr.m032599] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Long-chain acyl-CoA synthetases (ACSL) play key roles in fatty acid metabolism in liver and other metabolic tissues in an isozyme-specific manner. In this study, we examined the effects of a fructose-enriched diet on expressions of ACSL isoforms in the liver of hamsters. We showed that the fructose diet markedly reduced the mRNA and protein expressions of ACSL3 in hamster liver without significant effects on other ACSLs. The decrease in ACSL3 abundance was accompanied by a reduction in ACSL-catalyzed synthesis of arachidonyl-CoA and oleoyl-CoA in liver homogenates of hamsters fed the fructose diet as opposed to normal diet. We further showed that fructose diet specifically reduced expressions of three key components of the LXR signaling pathway, namely, liver X receptor (LXR)α, LXRβ, and retinoid X receptor (RXR)β. Exogenous expression and activation of LXRα/β increased hamster ACSL3 promoter activities in a LXR-responsive element (LXRE)-dependent fashion. Finally, we showed that treating hamsters with LXR agonist GW3965 increased hepatic ACSL3 expression without affecting other ACSL isoforms. Furthermore, the ligand-induced increases of ACSL3 expression were accompanied with the reduction of hepatic triglyceride levels in GW3965-treated hamster liver. Altogether, our studies demonstrate that fructose diet has a negative impact on LXR signaling pathway in liver tissue and reduction of ACSL3 expression/activity could be a causal factor for fructose-induced hepatic steatosis.
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Affiliation(s)
- Bin Dong
- Department of Veterans Affairs, Palo Alto Health Care System, Palo Alto, CA 94304, USA
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132
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Reineke EL, York B, Stashi E, Chen X, Tsimelzon A, Xu J, Newgard CB, Taffet GE, Taegtmeyer H, Entman ML, O’Malley BW. SRC-2 coactivator deficiency decreases functional reserve in response to pressure overload of mouse heart. PLoS One 2012; 7:e53395. [PMID: 23300926 PMCID: PMC3534027 DOI: 10.1371/journal.pone.0053395] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Accepted: 11/28/2012] [Indexed: 11/18/2022] Open
Abstract
A major component of the cardiac stress response is the simultaneous activation of several gene regulatory networks. Interestingly, the transcriptional regulator steroid receptor coactivator-2, SRC-2 is often decreased during cardiac failure in humans. We postulated that SRC-2 suppression plays a mechanistic role in the stress response and that SRC-2 activity is an important regulator of the adult heart gene expression profile. Genome-wide microarray analysis, confirmed with targeted gene expression analyses revealed that genetic ablation of SRC-2 activates the "fetal gene program" in adult mice as manifested by shifts in expression of a) metabolic and b) sarcomeric genes, as well as associated modulating transcription factors. While these gene expression changes were not accompanied by changes in left ventricular weight or cardiac function, imposition of transverse aortic constriction (TAC) predisposed SRC-2 knockout (KO) mice to stress-induced cardiac dysfunction. In addition, SRC-2 KO mice lacked the normal ventricular hypertrophic response as indicated through heart weight, left ventricular wall thickness, and blunted molecular signaling known to activate hypertrophy. Our results indicate that SRC-2 is involved in maintenance of the steady-state adult heart transcriptional profile, with its ablation inducing transcriptional changes that mimic a stressed heart. These results further suggest that SRC-2 deletion interferes with the timing and integration needed to respond efficiently to stress through disruption of metabolic and sarcomeric gene expression and hypertrophic signaling, the three key stress responsive pathways.
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Affiliation(s)
- Erin L. Reineke
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Brian York
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Erin Stashi
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Xian Chen
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Anna Tsimelzon
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, United States of America
| | - Jianming Xu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Christopher B. Newgard
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical School, Durham, North Carolina, United States of America
| | - George E. Taffet
- Department of Medicine, Division of Cardiovascular Sciences, Baylor College of Medicine, Houston, Texas, United States of America
| | - Heinrich Taegtmeyer
- Department of Internal Medicine, Division of Cardiology, The University of Texas Medical School at Houston, Houston, Texas, United States of America
| | - Mark L. Entman
- Department of Medicine, Division of Cardiovascular Sciences, Baylor College of Medicine, Houston, Texas, United States of America
| | - Bert W. O’Malley
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
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133
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Li X, Gonzalez O, Shen X, Barnhart S, Kramer F, Kanter JE, Vivekanandan-Giri A, Tsuchiya K, Handa P, Pennathur S, Kim F, Coleman RA, Schaffer JE, Bornfeldt KE. Endothelial acyl-CoA synthetase 1 is not required for inflammatory and apoptotic effects of a saturated fatty acid-rich environment. Arterioscler Thromb Vasc Biol 2012; 33:232-40. [PMID: 23241406 DOI: 10.1161/atvbaha.112.252239] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
OBJECTIVE Saturated fatty acids, such as palmitic and stearic acid, cause detrimental effects in endothelial cells and have been suggested to contribute to macrophage accumulation in adipose tissue and the vascular wall, in states of obesity and insulin resistance. Long-chain fatty acids are believed to require conversion into acyl-CoA derivatives to exert most of their detrimental effects, a reaction catalyzed by acyl-CoA synthetases (ACSLs). The objective of this study was to investigate the role of ACSL1, an ACSL isoform previously shown to mediate inflammatory effects in myeloid cells, in regulating endothelial cell responses to a saturated fatty acid-rich environment in vitro and in vivo. METHODS AND RESULTS Saturated fatty acids caused increased inflammatory activation, endoplasmic reticulum stress, and apoptosis in mouse microvascular endothelial cells. Forced ACSL1 overexpression exacerbated the effects of saturated fatty acids on apoptosis and endoplasmic reticulum stress. However, endothelial ACSL1 deficiency did not protect against the effects of saturated fatty acids in vitro, nor did it protect insulin-resistant mice fed a saturated fatty acid-rich diet from macrophage adipose tissue accumulation or increased aortic adhesion molecule expression. CONCLUSIONS Endothelial ACSL1 is not required for inflammatory and apoptotic effects of a saturated fatty acid-rich environment.
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Affiliation(s)
- Xin Li
- Departments of Pathology, University of Washington, Seattle WA, USA
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134
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Watkins SM, Hotamisligil GS. Promoting atherosclerosis in type 1 diabetes through the selective activation of arachidonic acid and PGE(2) production. Circ Res 2012; 111:394-6. [PMID: 22859668 DOI: 10.1161/circresaha.112.273508] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Type 1 diabetics harbor a greatly elevated risk for progressive atherosclerosis and cardiovascular events, but the mechanistic basis for this phenomenon is not entirely clear. Although this link is likely to involve many factors, the specific activation of a lipid-driven inflammatory phenotype in monocytes and macrophages of people with type 1 diabetes is an attractive causal mechanism, due to the ability of inflamed macrophages to exacerbate plaque deposition, expansion, and instability.
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135
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Wang HW, Fang JS, Kuang X, Miao LY, Wang C, Xia GL, King ML, Zhang J. Activity of long-chain acyl-CoA synthetase is required for maintaining meiotic arrest in Xenopus laevis. Biol Reprod 2012; 87:74. [PMID: 22786823 DOI: 10.1095/biolreprod.112.100511] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In most vertebrates, fully grown oocytes are arrested in meiotic prophase I and only resume the cell cycle upon external stimuli, such as hormones. The proper arrest and resumption of the meiotic cycle is critical for reproduction. A Galpha(S) signaling pathway essential for the arrest is conserved in organisms from Xenopus to mouse and human. A previous gene association study implicated that mutations of human ACSL6 may be related to premature ovarian failure. However, functional roles of ACSL6 in human infertility have yet to be reported. In the present study, we found that triacsin C, a potent and specific inhibitor for ACSL, triggers maturation in Xenopus and mouse oocytes in the absence of hormone, suggesting ACSL activity is required for the oocyte arrest. In Xenopus, acsl1b may fulfill a major role in the process, because inhibition of acsl1b by knocking down its RNA results in abnormal acceleration of oocyte maturation. Such abnormally matured eggs cannot support early embryonic development. Moreover, direct inhibition of protein palmitoylation, which lies downstream of ACSLs, also causes oocyte maturation. Furthermore, palmitoylation of Galpha(s), which is essential for its function, is inhibited when the ACSL activity is blocked by triacsin C in Xenopus. Thus, disruption of ACSL activity causes inhibition of the Galpha(s) signaling pathway in the oocytes, which may result in premature ovarian failure in human.
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Affiliation(s)
- Hua-wei Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
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136
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Yvert T, He ZH, Santiago C, Hu Y, Li YC, Gómez-Gallego F, Fiuza-Luces C, Verde Z, Muniesa CA, Oliván J, Santalla A, Ruiz JR, Lucia A. Acyl coenzyme A synthetase long-chain 1 (ACSL1) gene polymorphism (rs6552828) and elite endurance athletic status: a replication study. PLoS One 2012; 7:e41268. [PMID: 22829935 PMCID: PMC3400600 DOI: 10.1371/journal.pone.0041268] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 06/19/2012] [Indexed: 12/16/2022] Open
Abstract
The aim of this study was to determine the association between the rs6552828 polymorphism in acyl coenzyme A synthetase (ACSL1) and elite endurance athletic status. We studied 82 Caucasian (Spanish) World/Olympic-class endurance male athletes, and a group of sex and ethnically matched healthy young adults (controls, n = 197). The analyses were replicated in a cohort of a different ethnic origin (Chinese of the Han ethnic group), composed of elite endurance athletes (runners) [cases, n = 241 (128 male)] and healthy sedentary adults [controls, n = 504 (267 male)]. In the Spanish cohort, genotype (P = 0.591) and minor allele (A) frequencies were similar in cases and controls (P = 0.978). In the Chinese cohort, genotype (P = 0.973) and minor allele (G) frequencies were comparable in female endurance athletes and sedentary controls (P = 0.881), whereas in males the frequency of the G allele was higher in endurance athletes (0.40) compared with their controls (0.32, P = 0.040). The odds ratio (95%CI) for an elite endurance Chinese athlete to carry the G allele compared with ethnically matched controls was 1.381 (1.015–1.880) (P-value = 0.04). Our findings suggest that the ACSL1 gene polymorphism rs6552828 is not associated with elite endurance athletic status in Caucasians, yet a marginal association seems to exist for the Chinese (Han) male population.
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Affiliation(s)
- Thomas Yvert
- Department of Biomedicine, European University of Madrid, Madrid, Spain
| | - Zi-Hong He
- Biology Center, China Institute of Sport Science, Beijing, China
| | - Catalina Santiago
- Department of Biomedicine, European University of Madrid, Madrid, Spain
| | - Yang Hu
- Science and Research Center of Beijing Sports University, Beijing, China
| | - Yan-Chun Li
- Science and Research Center of Beijing Sports University, Beijing, China
| | | | | | - Zoraida Verde
- Department of Biomedicine, European University of Madrid, Madrid, Spain
| | - Carlos A. Muniesa
- Faculty of Sports Sciences, European University of Madrid, Madrid, Spain
| | - Jesús Oliván
- Faculty of Sports Sciences, European University of Madrid, Madrid, Spain
| | - Alfredo Santalla
- Faculty of Sports Sciences, Pabo de Olavide University, Seville, Spain
| | - Jonatan R. Ruiz
- Department of Physical Education and Sport, School of Sport Sciences, University of Granada, Granada, Spain
- Department of Biosciences and Nutrition at NOVUM, Unit for Preventive Nutrition, Karolinska Institutet, Stockholm, Sweden
| | - Alejandro Lucia
- Department of Biomedicine, European University of Madrid, Madrid, Spain
- * E-mail:
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137
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Associations between gene polymorphisms in two crucial metabolic pathways and growth traits in pigs. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/s11434-012-5328-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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138
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Myocardial triacylglycerol metabolism. J Mol Cell Cardiol 2012; 55:101-10. [PMID: 22789525 DOI: 10.1016/j.yjmcc.2012.06.018] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Revised: 06/22/2012] [Accepted: 06/28/2012] [Indexed: 11/22/2022]
Abstract
Myocardial triacylglycerol (TAG) constitutes a highly dynamic fatty acid (FA) storage pool that can be used for an energy reserve in the cardiomyocyte. However, derangements in myocardial TAG metabolism and accumulation are commonly associated with cardiac disease, suggesting an important role of intramyocardial TAG turnover in the regulation of cardiac function. In cardiomyocytes, TAG is synthesized by acyltransferases and phosphatases at the sarcoplasmic reticulum and mitochondrial membrane and then packaged into cytosolic lipid droplets for temporary storage or into lipoproteins for secretion. A complex interplay among lipases, lipase regulatory proteins, and lipid droplet scaffold proteins leads to the controlled release of FAs from the cardiac TAG pool for subsequent mitochondrial β-oxidation and energy production. With the identification and characterization of proteins involved in myocardial TAG metabolism as well as the identification of the importance of cardiac TAG turnover, it is now evident that adequate regulation of myocardial TAG metabolism is critical for both cardiac energy metabolism and function. In this article, we review the current understanding of myocardial TAG metabolism and discuss the potential role of myocardial TAG turnover in cardiac health and disease. This article is part of a Special Issue entitled "Focus on Cardiac Metabolism".
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139
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Aloysius H, Tong VW, Yabut J, Bradley SA, Shang J, Zou Y, Tschirret-Guth RA. Metabolic Activation and Major Protein Target of a 1-Benzyl-3-carboxyazetidine Sphingosine-1-phosphate-1 Receptor Agonist. Chem Res Toxicol 2012; 25:1412-22. [DOI: 10.1021/tx300017s] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Herve Aloysius
- Department of Pharmacokinetics,
Pharmacodynamics, and
Drug Metabolism, Merck Research Laboratories, Rahway, New Jersey 07065, United States
| | - Vincent W. Tong
- Department of Pharmacokinetics,
Pharmacodynamics, and
Drug Metabolism, Merck Research Laboratories, Rahway, New Jersey 07065, United States
| | - Jocelyn Yabut
- Department of Pharmacokinetics,
Pharmacodynamics, and
Drug Metabolism, Merck Research Laboratories, Rahway, New Jersey 07065, United States
| | - Scott A. Bradley
- Department of Pharmacokinetics,
Pharmacodynamics, and
Drug Metabolism, Merck Research Laboratories, Rahway, New Jersey 07065, United States
| | - Jackie Shang
- Department of Pharmacokinetics,
Pharmacodynamics, and
Drug Metabolism, Merck Research Laboratories, Rahway, New Jersey 07065, United States
| | - Yan Zou
- Department of Pharmacokinetics,
Pharmacodynamics, and
Drug Metabolism, Merck Research Laboratories, Rahway, New Jersey 07065, United States
| | - Richard A. Tschirret-Guth
- Department of Pharmacokinetics,
Pharmacodynamics, and
Drug Metabolism, Merck Research Laboratories, Rahway, New Jersey 07065, United States
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140
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Abstract
The heart has both the greatest caloric needs and the most robust oxidation of fatty acids (FAs). Under pathological conditions such as obesity and type 2 diabetes, cardiac uptake and oxidation are not balanced and hearts accumulate lipid potentially leading to cardiac lipotoxicity. We will first review the pathways utilized by the heart to acquire FAs from the circulation and to store triglyceride intracellularly. Then we will describe mouse models in which excess lipid accumulation causes heart dysfunction and experiments performed to alleviate this toxicity. Finally, the known relationships between heart lipid metabolism and dysfunction in humans will be summarized.
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Affiliation(s)
- Ira J Goldberg
- Department of Medicine, Columbia University, New York, NY 10032, USA.
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141
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Teng YW, Ellis JM, Coleman RA, Zeisel SH. Mouse betaine-homocysteine S-methyltransferase deficiency reduces body fat via increasing energy expenditure and impairing lipid synthesis and enhancing glucose oxidation in white adipose tissue. J Biol Chem 2012; 287:16187-98. [PMID: 22362777 DOI: 10.1074/jbc.m111.303255] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Betaine-homocysteine S-methyltransferase (BHMT) catalyzes the synthesis of methionine from homocysteine. In our initial report, we observed a reduced body weight in Bhmt(-/-) mice. We initiated this study to investigate the potential role of BHMT in energy metabolism. Compared with the controls (Bhmt(+/+)), Bhmt(-/-) mice had less fat mass, smaller adipocytes, and better glucose and insulin sensitivities. Compared with the controls, Bhmt(-/-) mice had increased energy expenditure, with no changes in food intake, fat uptake or absorption, or in locomotor activity. The reduced adiposity in Bhmt(-/-) mice was not due to hyperthermogenesis. Bhmt(-/-) mice failed to maintain a normal body temperature upon cold exposure because of limited fuel supplies. In vivo and ex vivo tests showed that Bhmt(-/-) mice had normal lipolytic function. The rate of (14)C-labeled fatty acid incorporated into [(14)C]triacylglycerol was the same in Bhmt(+/+) and Bhmt(-/-) gonadal fat depots (GWAT), but it was 62% lower in Bhmt(-/-) inguinal fat depots (IWAT) compared with that of Bhmt(+/+) mice. The rate of (14)C-labeled fatty acid oxidation was the same in both GWAT and IWAT from Bhmt(+/+) and Bhmt(-/-) mice. At basal level, Bhmt(-/-) GWAT had the same [(14)C]glucose oxidation as did the controls. When stimulated with insulin, Bhmt(-/-) GWAT oxidized 2.4-fold more glucose than did the controls. Compared with the controls, the rate of [(14)C]glucose oxidation was 2.4- and 1.8-fold higher, respectively, in Bhmt(-/-) IWAT without or with insulin stimulus. Our results show for the first time a role for BHMT in energy homeostasis.
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Affiliation(s)
- Ya-Wen Teng
- Department of Nutrition, School of Public Health, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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142
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Kok BPC, Kienesberger PC, Dyck JRB, Brindley DN. Relationship of glucose and oleate metabolism to cardiac function in lipin-1 deficient (fld) mice. J Lipid Res 2011; 53:105-18. [PMID: 22058427 DOI: 10.1194/jlr.m019430] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Lipin-1 is the major phosphatidate phosphatase (PAP) in the heart and a transcriptional coactivator that regulates fatty acid (FA) oxidation in the liver. As the control of FA metabolism is essential for maintaining cardiac function, we investigated whether lipin-1 deficiency affects cardiac metabolism and performance. Cardiac PAP activity in lipin-1 deficient [fatty liver dystrophy (fld)] mice was decreased by >80% compared with controls. Surprisingly, oleate oxidation and incorporation in triacylglycerol (TG), as well as glucose oxidation, were not significantly different in perfused working fld hearts. Despite this, [³H]oleate accumulation in phosphatidate and phosphatidylinositol was increased in fld hearts, reflecting the decreased PAP activity. Phosphatidate accumulation was linked to increased cardiac mammalian target of rapamycin complex 1 (mTORC1) signaling and endoplasmic reticulum (ER) stress. Transthoracic echocardiography showed decreased cardiac function in fld mice; however, cardiac dysfunction was not observed in ex vivo perfused working fld hearts. This showed that changes in systemic factors due to the global absence of lipin-1 could contribute to the decreased cardiac function in vivo. Collectively, this study shows that fld hearts exhibit unchanged oleate esterification, as well as oleate and glucose oxidation, despite the absence of lipin-1. However, lipin-1 deficiency increases the accumulation of newly synthesized phosphatidate and induces aberrant cell signaling.
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Affiliation(s)
- Bernard P C Kok
- Signal Transduction Research Group, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada
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143
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Miranda DA, Koves TR, Gross DA, Chadt A, Al-Hasani H, Cline GW, Schwartz GJ, Muoio DM, Silver DL. Re-patterning of skeletal muscle energy metabolism by fat storage-inducing transmembrane protein 2. J Biol Chem 2011; 286:42188-42199. [PMID: 22002063 DOI: 10.1074/jbc.m111.297127] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Triacylglyceride stored in cytosolic lipid droplets (LDs) constitutes a major energy reservoir in most eukaryotes. The regulated turnover of triacylglyceride in LDs provides fatty acids for mitochondrial β-oxidation and ATP generation in physiological states of high demand for energy. The mechanisms for the formation of LDs in conditions of energy excess are not entirely understood. Fat storage-inducing transmembrane protein 2 (FIT2/FITM2) is the anciently conserved member of the fat storage-inducing transmembrane family of proteins implicated to be important in the formation of LDs, but its role in energy metabolism has not been tested. Here, we report that expression of FIT2 in mouse skeletal muscle had profound effects on muscle energy metabolism. Mice with skeletal muscle-specific overexpression of FIT2 (CKF2) had significantly increased intramyocellular triacylglyceride and complete protection from high fat diet-induced weight gain due to increased energy expenditure. Mass spectrometry-based metabolite profiling suggested that CKF2 skeletal muscle had increased oxidation of branched chain amino acids but decreased oxidation of fatty acids. Glucose was primarily utilized in CKF2 muscle for synthesis of the glycerol backbone of triacylglyceride and not for glycogen production. CKF2 muscle was ATP-deficient and had activated AMP kinase. Together, these studies indicate that FIT2 expression in skeletal muscle plays an unexpected function in regulating muscle energy metabolism and indicates an important role for lipid droplet formation in this process.
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Affiliation(s)
- Diego A Miranda
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Timothy R Koves
- Sarah W. Stedman Nutrition and Metabolism Center, Department of Medicine, Duke University, Durham, North Carolina 27704
| | - David A Gross
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Alexandra Chadt
- Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, 40225 Dusseldorf, Germany
| | - Hadi Al-Hasani
- Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, 40225 Dusseldorf, Germany
| | - Gary W Cline
- Diabetes Endocrinology Research Center, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Gary J Schwartz
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Deborah M Muoio
- Sarah W. Stedman Nutrition and Metabolism Center, Department of Medicine, Duke University, Durham, North Carolina 27704
| | - David L Silver
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461.
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144
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Kanter JE, Tang C, Oram JF, Bornfeldt KE. Acyl-CoA synthetase 1 is required for oleate and linoleate mediated inhibition of cholesterol efflux through ATP-binding cassette transporter A1 in macrophages. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:358-64. [PMID: 22020260 DOI: 10.1016/j.bbalip.2011.10.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 09/30/2011] [Accepted: 10/01/2011] [Indexed: 12/31/2022]
Abstract
Diabetes and insulin resistance increase the risk of cardiovascular disease caused by atherosclerosis through mechanisms that are poorly understood. Lipid-loaded macrophages are key contributors to all stages of atherosclerosis. We have recently shown that diabetes associated with increased plasma lipids reduces cholesterol efflux and levels of the reverse cholesterol transporter ABCA1 (ATP-binding cassette transporter A1) in mouse macrophages, which likely contributes to macrophage lipid accumulation in diabetes. Furthermore, we and others have shown that unsaturated fatty acids reduce ABCA1-mediated cholesterol efflux, and that this effect is mediated by the acyl-CoA derivatives of the fatty acids. We therefore investigated whether acyl-CoA synthetase 1 (ACSL1), a key enzyme mediating acyl-CoA synthesis in macrophages, could directly influence ABCA1 levels and cholesterol efflux in these cells. Mouse macrophages deficient in ACSL1 exhibited reduced sensitivity to oleate- and linoleate-mediated ABCA1 degradation, which resulted in increased ABCA1 levels and increased apolipoprotein A-I-dependent cholesterol efflux in the presence of these fatty acids, as compared with wildtype mouse macrophages. Conversely, overexpression of ACSL1 resulted in reduced ABCA1 levels and reduced cholesterol efflux in the presence of unsaturated fatty acids. Thus, the reduced ABCA1 and cholesterol efflux in macrophages subjected to conditions of diabetes and elevated fatty load may, at least in part, be mediated by ACSL1. These observations raise the possibility that ABCA1 levels could be increased by inhibition of acyl-CoA synthetase activity in vivo. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).
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Affiliation(s)
- Jenny E Kanter
- Department of Pathology, Diabetes and Obesity Center of Excellence, University of Washington School of Medicine, Seattle, WA 98109, USA
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145
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Frahm JL, Li LO, Grevengoed TJ, Coleman RA. Phosphorylation and Acetylation of Acyl-CoA Synthetase- I. ACTA ACUST UNITED AC 2011; 4:129-137. [PMID: 24039348 DOI: 10.4172/jpb.1000180] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Long chain acyl-CoA synthetase 1 (ACSL1) contributes 50 to 90% of total ACSL activity in liver, adipose tissue, and heart and appears to direct the use of long chain fatty acids for energy. Although the functional importance of ACSL1 is becoming clear, little is understood about its post-translational regulation. In order to investigate the post-translational modifications of ACSL1 under different physiological conditions, we overexpressed ACSL1 in hepatocytes, brown adipocytes, and 3T3-L1 differentiated adipocytes, treated these cells with different hormones, and analyzed the resulting phosphorylated and acetylated amino acids by mass spectrometry. We then compared these results to the post-translational modifications observed in vivo in liver and brown adipose tissue after mice were fasted or exposed to a cold environment. We identified universal N-terminal acetylation, 15 acetylated lysines, and 25 phosphorylation sites on ACSL1. Several unique acetylation and phosphorylation sites occurred under conditions in which fatty acid β-oxidation is normally enhanced. Thirteen of the acetylated lysines had not previously been identified, and none of the phosphorylation sites had been previously identified. Site-directed mutagenesis was used to introduce mutations at three potential acetylation and phosphorylation sites believed to be important for ACSL1 function. At the ATP/AMP binding site and at a highly conserved site near the C terminus, modifications of Ser278 or Lys676, respectively, totally inhibited ACSL1 activity. In contrast, mutations of Lys285 that mimicked acetylation (Lys285Ala and Lys285Gln) reduced ACSL activity, whereas full activity was retained by Lys285Arg, suggesting that acetylation of Lys285 would be likely to decrease ACSL1 activity. These results indicate that ACSL1 is highly modified post-translationally. Several of these modifications would be expected to alter enzymatic function, but others may affect protein stability or protein-protein interactions.
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Affiliation(s)
- Jennifer L Frahm
- Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina 27599
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