101
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Li T, Xu D, Zuo B, Lei M, Xiong Y, Chen H, Zhou Y, Wu X. Ectopic overexpression of porcine DGAT1 increases intramuscular fat content in mouse skeletal muscle. Transgenic Res 2012; 22:187-94. [PMID: 22826105 DOI: 10.1007/s11248-012-9633-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 07/02/2012] [Indexed: 10/28/2022]
Abstract
The microsomal enzyme 1, 2-acyl CoA: diacylglyceroltransferase-1 (DGAT1) plays an important role in triglyceride storage in adipose tissue and expresses in skeletal muscle as well. The primary goal of the present study was to investigate the effect of porcine DGAT1 on intramuscular fat (IMF) content of transgenic mice produced by pronuclear microinjection with muscle specific promoter of porcine muscle creatine kinase (MCK). In normal chow-fed diet, 4 month-old male transgenic mice expressed more DGAT1, ACC1, UCP1, and FABP4 mRNAs and proteins in skeletal muscle than control mice by real-time PCR and western blot. No significant changes were detected for ACC2, CD36, ADRP, PPAR gamma and LPL. Triacylglycerol assay and soleus muscle sections showed overexpression of porcine DGAT1 in skeletal muscle increased intramyocellular triglyceride and percent of the total cell surface covered by lipid droplets. Thus, upregulation of porcine DGAT1 in skeletal muscle increases IMF content. The present study may further serve to develop transgenic pigs with higher IMF content and improved meat quality.
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Affiliation(s)
- Ting Li
- Key Laboratory of Swine Genetics and Breeding, Ministry of Agriculture and Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction, Ministry of Education, College of Animal Science, Huazhong Agricultural University, Wuhan, 430070, China
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102
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Visser B, Roelofs D, Hahn DA, Teal PEA, Mariën J, Ellers J. Transcriptional changes associated with lack of lipid synthesis in parasitoids. Genome Biol Evol 2012; 4:752-62. [PMID: 22820524 PMCID: PMC3509892 DOI: 10.1093/gbe/evs065] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/16/2012] [Indexed: 01/04/2023] Open
Abstract
Phenotypic regression of morphological, behavioral, or physiological traits can evolve when reduced trait expression has neutral or beneficial effects on overall performance. Studies on the evolution of phenotypic degradation in animals have concentrated mostly on the evaluation of resulting phenotypes, whereas much less research has been dedicated to uncovering the molecular mechanisms that underlie phenotypic regression. The majority of parasitoids (i.e., insects that develop on or inside other arthropods), do not accumulate lipid reserves during their free-living adult life-stage and represent an excellent system to study phenotypic regression in animals. Here, we study transcriptional patterns associated with lack of lipogenesis in the parasitic wasp Nasonia vitripennis. We first confirmed that N. vitripennis does not synthesize lipids by showing a reduction in lipid reserves despite ingestion of dietary sugar, and a lack of incorporation of isotopic labels into lipid reserves when fed deuterated sugar solution. Second, we investigated transcriptional responses of 28 genes involved in lipid and sugar metabolism in short- and long-term sugar-fed females relative to starved females of N. vitripennis. Sugar feeding did not induce transcription of fatty acid synthase (fas) or other key genes involved in the lipid biosynthesis pathway. Furthermore, several genes involved in carbohydrate metabolism had a lower transcription in fed than in starved females. Our results reveal that N. vitripennis gene transcription in response to dietary sugar deviates markedly from patterns typically observed in other organisms. This study is the first to identify differential gene transcription associated with lack of lipogenesis in parasitoids and provides new insights into the molecular mechanism that underlies phenotypic regression of this trait.
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Affiliation(s)
- Bertanne Visser
- Department of Ecological Science, Section Animal Ecology, VU University Amsterdam, The Netherlands.
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103
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Design, synthesis, and structure–activity relationships of novel spiro-piperidines as acetyl-CoA carboxylase inhibitors. Bioorg Med Chem Lett 2012; 22:3643-7. [DOI: 10.1016/j.bmcl.2012.04.047] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 04/02/2012] [Accepted: 04/09/2012] [Indexed: 11/22/2022]
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104
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Vrablik TL, Watts JL. Emerging roles for specific fatty acids in developmental processes. Genes Dev 2012; 26:631-7. [PMID: 22474257 DOI: 10.1101/gad.190777.112] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Animals synthesize a vast range of fatty acids serving diverse cellular functions. The roles of specific fatty acids in early development are just beginning to be characterized. In the March 15, 2012, issue of Genes & Development, Kniazeva and colleagues (pp. 554-566) describe how the particular combination of a branched chain fatty acid and an acyl-CoA synthetase is required for critical cellular processes during early embryogenesis in Caenorhabditis elegans.
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Affiliation(s)
- Tracy L Vrablik
- School of Molecular Biosciences, Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
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105
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Abu-Elheiga L, Wu H, Gu Z, Wakil SJ. Reply to Hoehn et al.: Phenotypic Discrepancies in Acetyl-CoA Carboxylase 2-deficient Mice. J Biol Chem 2012. [DOI: 10.1074/jbc.o112.362939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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106
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Abstract
Polyunsaturated fatty acids (PUFA) play important roles in the normal physiology and in pathological states including inflammation and cancer. While much is known about the biosynthesis and biological activities of eicosanoids derived from ω6 PUFA, our understanding of the corresponding ω3 series lipid mediators is still rudimentary. The purpose of this review is not to offer a comprehensive summary of the literature on fatty acids in prostate cancer but rather to highlight some of the areas where key questions remain to be addressed. These include substrate preference and polymorphic variants of enzymes involved in the metabolism of PUFA, the relationship between de novo lipid synthesis and dietary lipid metabolism pathways, the contribution of cyclooxygenases and lipoxygenases as well as terminal synthases and prostanoid receptors in prostate cancer, and the potential role of PUFA in angiogenesis and cell surface receptor signaling.
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107
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Abu-Elheiga L, Wu H, Gu Z, Bressler R, Wakil SJ. Acetyl-CoA carboxylase 2-/- mutant mice are protected against fatty liver under high-fat, high-carbohydrate dietary and de novo lipogenic conditions. J Biol Chem 2012; 287:12578-88. [PMID: 22362781 DOI: 10.1074/jbc.m111.309559] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Hepatic fat accumulation resulting from increased de novo fatty acid synthesis leads to hepatic steatosis and hepatic insulin resistance. We have shown previously that acetyl-CoA carboxylase 2 (Acc2(-/-)) mutant mice, when fed a high-fat (HF) or high-fat, high-carbohydrate (HFHC) diet, are protected against diet-induced obesity and maintained whole body and hepatic insulin sensitivity. To determine the effect of an ACC2 deletion on hepatic fat metabolism, we studied the regulation of the enzymes involved in the lipogenic pathway under Western HFHC dietary and de novo lipogenic conditions. After completing the HFHC regimen, Acc2(-/-) mutant mice were found to have lower body weight, smaller epididymal fat pads, lower blood levels of nonesterified fatty acids and triglycerides, and higher hepatic cholesterol than wild-type mice. Significant up-regulation of lipogenic enzymes and an elevation in hepatic peroxisome proliferator-activated receptor-γ (PPAR-γ) protein were found in Acc2(-/-) mutant mice under de novo lipogenic conditions. The increase in lipogenic enzyme levels was accompanied by up-regulation of the transcription factors, sterol regulatory element-binding proteins 1 and 2, and carbohydrate response element-binding protein. In contrast, hepatic levels of the PPAR-γ and PPAR-α proteins were significantly lower in the Acc2(-/-) mutant mice fed an HFHC diet. When compared with wild-type mice fed the same diet, Acc2(-/-) mutant mice exhibited a similar level of AKT but with a significant increase in pAKT. Hence, deleting ACC2 ameliorates the metabolic syndrome and protects against fatty liver despite increased de novo lipogenesis and dietary conditions known to induce obesity and diabetes.
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Affiliation(s)
- Lutfi Abu-Elheiga
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
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108
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Saloniemi T, Jokela H, Strauss L, Pakarinen P, Poutanen M. The diversity of sex steroid action: novel functions of hydroxysteroid (17β) dehydrogenases as revealed by genetically modified mouse models. J Endocrinol 2012; 212:27-40. [PMID: 22045753 DOI: 10.1530/joe-11-0315] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Disturbed action of sex steroid hormones, i.e. androgens and estrogens, is involved in the pathogenesis of various severe diseases in humans. Interestingly, recent studies have provided data further supporting the hypothesis that the circulating hormone concentrations do not explain all physiological and pathological processes observed in hormone-dependent tissues, while the intratissue sex steroid concentrations are determined by the expression of steroid metabolising enzymes in the neighbouring cells (paracrine action) and/or by target cells themselves (intracrine action). This local sex steroid production is also a valuable treatment option for developing novel therapies against hormonal diseases. Hydroxysteroid (17β) dehydrogenases (HSD17Bs) compose a family of 14 enzymes that catalyse the conversion between the low-active 17-keto steroids and the highly active 17β-hydroxy steroids. The enzymes frequently expressed in sex steroid target tissues are, thus, potential drug targets in order to lower the local sex steroid concentrations. The present review summarises the recent data obtained for the role of HSD17B1, HSD17B2, HSD17B7 and HSD17B12 enzymes in various metabolic pathways and their physiological and pathophysiological roles as revealed by the recently generated genetically modified mouse models. Our data, together with that provided by others, show that, in addition to having a role in sex steroid metabolism, several of these HSD17B enzymes possess key roles in other metabolic processes: for example, HD17B7 is essential for cholesterol biosynthesis and HSD17B12 is involved in elongation of fatty acids. Additional studies in vitro and in vivo are to be carried out in order to fully define the metabolic role of the HSD17B enzymes and to evaluate their value as drug targets.
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Affiliation(s)
- Taija Saloniemi
- Department of Physiology, Institute of Biomedicine, University of Turku, Kiinamyllynkatu 10, FI-20014 Turku, Finland
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109
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Rajamohan F, Marr E, Reyes AR, Landro JA, Anderson MD, Corbett JW, Dirico KJ, Harwood JH, Tu M, Vajdos FF. Structure-guided inhibitor design for human acetyl-coenzyme A carboxylase by interspecies active site conversion. J Biol Chem 2011; 286:41510-41519. [PMID: 21953464 PMCID: PMC3308862 DOI: 10.1074/jbc.m111.275396] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 09/07/2011] [Indexed: 11/06/2022] Open
Abstract
Inhibition of acetyl-CoA carboxylases (ACCs), a crucial enzyme for fatty acid metabolism, has been shown to promote fatty acid oxidation and reduce body fat in animal models. Therefore, ACCs are attractive targets for structure-based inhibitor design, particularly the carboxyltransferase (CT) domain, which is the primary site for inhibitor interaction. We have cloned, expressed, and purified the CT domain of human ACC2 using baculovirus-mediated insect cell expression system. However, attempts to crystallize the human ACC2 CT domain have not been successful in our hands. Hence, we have been using the available crystal structure of yeast CT domain to design human ACC inhibitors. Unfortunately, as the selectivity of the lead series has increased against the full-length human enzyme, the potency against the yeast enzyme has decreased significantly. This loss of potency against the yeast enzyme correlated with a complete lack of binding of the human-specific compounds to crystals of the yeast CT domain. Here, we address this problem by converting nine key active site residues of the yeast CT domain to the corresponding human residues. The resulting humanized yeast ACC-CT (yCT-H9) protein exhibits biochemical and biophysical properties closer to the human CT domain and binding to human specific compounds. We report high resolution crystal structures of yCT-H9 complexed with inhibitors that show a preference for the human CT domain. These structures offer insights that explain the species selectivity of ACC inhibitors and may guide future drug design programs.
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Affiliation(s)
| | - Eric Marr
- Pfizer Global Research and Development, Groton, Connecticut 06340
| | - Allan R Reyes
- Pfizer Global Research and Development, Groton, Connecticut 06340
| | - James A Landro
- Pfizer Global Research and Development, Groton, Connecticut 06340
| | - Marie D Anderson
- Pfizer Global Research and Development, Groton, Connecticut 06340
| | | | - Kenneth J Dirico
- Pfizer Global Research and Development, Groton, Connecticut 06340
| | - James H Harwood
- Pfizer Global Research and Development, Groton, Connecticut 06340
| | - Meihua Tu
- Pfizer Global Research and Development, Groton, Connecticut 06340
| | - Felix F Vajdos
- Pfizer Global Research and Development, Groton, Connecticut 06340.
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110
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Gathercole LL, Morgan SA, Bujalska IJ, Hauton D, Stewart PM, Tomlinson JW. Regulation of lipogenesis by glucocorticoids and insulin in human adipose tissue. PLoS One 2011; 6:e26223. [PMID: 22022575 PMCID: PMC3194822 DOI: 10.1371/journal.pone.0026223] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 09/22/2011] [Indexed: 12/16/2022] Open
Abstract
Patients with glucocorticoid (GC) excess, Cushing's syndrome, develop a classic phenotype characterized by central obesity and insulin resistance. GCs are known to increase the release of fatty acids from adipose, by stimulating lipolysis, however, the impact of GCs on the processes that regulate lipid accumulation has not been explored. Intracellular levels of active GC are dependent upon the activity of 11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) and we have hypothesized that 11β-HSD1 activity can regulate lipid homeostasis in human adipose tissue (Chub-S7 cell line and primary cultures of human subcutaneous (sc) and omental (om) adipocytes. Across adipocyte differentiation, lipogenesis increased whilst β-oxidation decreased. GC treatment decreased lipogenesis but did not alter rates of β-oxidation in Chub-S7 cells, whilst insulin increased lipogenesis in all adipocyte cell models. Low dose Dexamethasone pre-treatment (5 nM) of Chub-S7 cells augmented the ability of insulin to stimulate lipogenesis and there was no evidence of adipose tissue insulin resistance in primary sc cells. Both cortisol and cortisone decreased lipogenesis; selective 11β-HSD1 inhibition completely abolished cortisone-mediated repression of lipogenesis. GCs have potent actions upon lipid homeostasis and these effects are dependent upon interactions with insulin. These in vitro data suggest that manipulation of GC availability through selective 11β-HSD1 inhibition modifies lipid homeostasis in human adipocytes.
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Affiliation(s)
- Laura L. Gathercole
- Centre for Endocrinology, Diabetes and Metabolism, Institute of Biomedical Research, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom
| | - Stuart A. Morgan
- Centre for Endocrinology, Diabetes and Metabolism, Institute of Biomedical Research, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom
| | - Iwona J. Bujalska
- Centre for Endocrinology, Diabetes and Metabolism, Institute of Biomedical Research, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom
| | - David Hauton
- Centre for Endocrinology, Diabetes and Metabolism, Institute of Biomedical Research, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom
| | - Paul M. Stewart
- Centre for Endocrinology, Diabetes and Metabolism, Institute of Biomedical Research, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom
| | - Jeremy W. Tomlinson
- Centre for Endocrinology, Diabetes and Metabolism, Institute of Biomedical Research, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom
- * E-mail:
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111
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Gambino R, Musso G, Cassader M. Redox balance in the pathogenesis of nonalcoholic fatty liver disease: mechanisms and therapeutic opportunities. Antioxid Redox Signal 2011; 15:1325-65. [PMID: 20969475 DOI: 10.1089/ars.2009.3058] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is currently the most common liver disease in the world. It encompasses a histological spectrum, ranging from simple, nonprogressive steatosis to nonalcoholic steatohepatitis (NASH), which may progress to cirrhosis and hepatocellular carcinoma. While liver-related complications are confined to NASH, emerging evidence suggests both simple steatosis and NASH predispose to type 2 diabetes and cardiovascular disease. The pathogenesis of NAFLD is currently unknown, but accumulating data suggest that oxidative stress and altered redox balance play a crucial role in the pathogenesis of steatosis, steatohepatitis, and fibrosis. We will examine intracellular mechanisms, including mitochondrial dysfunction and impaired oxidative free fatty acid metabolism, leading to reactive oxygen species generation; additionally, the potential pathogenetic role of extracellular sources of reactive oxygen species in NAFLD, including increased myeloperoxidase activity and oxidized low density lipoprotein accumulation, will be reviewed. We will discuss how these mechanisms converge to determine the whole pathophysiological spectrum of NAFLD, including hepatocyte triglyceride accumulation, hepatocyte apoptosis, hepatic inflammation, hepatic stellate cell activation, and fibrogenesis. Finally, available animal and human data on treatment opportunities with older and newer antioxidant will be presented.
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Affiliation(s)
- Roberto Gambino
- Department of Internal Medicine, University of Turin, Turin, Italy
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112
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Affiliation(s)
- Hanley N Abramson
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, 259 Mack Avenue, Detroit, Michigan 48201, USA.
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113
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Rebholz SL, Burke KT, Yang Q, Tso P, Woollett LA. Dietary fat impacts fetal growth and metabolism: uptake of chylomicron remnant core lipids by the placenta. Am J Physiol Endocrinol Metab 2011; 301:E416-25. [PMID: 21586694 PMCID: PMC3154537 DOI: 10.1152/ajpendo.00619.2010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The fetus requires significant energy for growth and development. Although glucose is a major source of energy for the fetus, other maternal nutrients also appear to promote growth. Thus, the goal of these studies was to determine whether triglyceride-rich remnants are taken up by the placenta and whether maternal dietary lipids, independently of adiposity, can impact fetal growth. To accomplish our first goal, chylomicron particles were duallly labeled with cholesteryl ester and triglycerides. The placenta took up remnant particles/core lipids at rates greater than adipose tissue and skeletal muscle but less than the liver. Although the placenta expresses apoE receptors, uptake of chylomicron remnants and/or core lipids can occur independently of apoE. To determine the impact of dietary lipid on fetal growth, independent of maternal adiposity, females were fed high-fat diets (HFD) for 1 mo; there was no change in adiposity or leptin levels prior to or during pregnancy of dams fed HFD. Fetal masses were greater in dams fed HFD, and mRNA levels of proteins involved in fatty acid oxidation (CPT I, PPARα), but not glucose oxidation (pyruvate kinase) or other regulatory processes (HNF-4α, LXR), were increased with maternal dietary fat. There was also no change in mRNA levels of proteins involved in placental glucose and fatty acid transport, and GLUT1 protein levels in microvillous membranes were similar in placentas of dams fed either diet. Thus, the ability of the placenta to take up chylomicron remnant core lipids likely contributes to accelerated fetal growth in females fed high fat diets.
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Affiliation(s)
- Sandra L Rebholz
- Department of Pathology and Laboratory Medicine, University of Cincinnati Medical School, 2180 E. Galbraith Rd., Cincinnati, OH 45237, USA
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114
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Liver X Receptor: an oxysterol sensor and a major player in the control of lipogenesis. Chem Phys Lipids 2011; 164:500-14. [PMID: 21693109 DOI: 10.1016/j.chemphyslip.2011.06.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 06/04/2011] [Accepted: 06/06/2011] [Indexed: 01/12/2023]
Abstract
De novo fatty acid biosynthesis is also called lipogenesis. It is a metabolic pathway that provides the cells with fatty acids required for major cellular processes such as energy storage, membrane structures and lipid signaling. In this article we will review the role of the Liver X Receptors (LXRs), nuclear receptors that sense oxysterols, in the transcriptional regulation of genes involved in lipogenesis.
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115
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Hu G, Wang S, Tian J, Chu L, Li H. Epistatic effect between ACACA and FABP2 gene on abdominal fat traits in broilers. J Genet Genomics 2011; 37:505-12. [PMID: 20816383 DOI: 10.1016/s1673-8527(09)60070-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 04/28/2010] [Accepted: 04/29/2010] [Indexed: 02/02/2023]
Abstract
Epistasis is generally defined as the interaction between two or more genes or their mRNA or protein products to influence a single trait. Experimental evidence suggested that epistasis could be important in the determination of the genetic architecture of complex traits in domestic animals. Acetyl-coenzyme A carboxylase alpha (ACACA) and fatty acid binding protein 2 (FABP2) are both key factors of lipogenesis and transport. They may play a crucial role in the weight variability of abdominal adipose tissue in the growing chicken. In this study, the polymorphisms of c.2292G>A in ACACA and c.-561A>C in FABP2 were detected among individuals from two broiler lines which were divergently selected for abdominal fat content. Epistasis between the two SNPs on abdominal fat weight (AFW) and abdominal fat percentage (AFP) was analyzed. The additive x additive epistatic components between these two SNPs were found significant or suggestively significant on both AFW and AFP in lean lines of the 9th and 10th generation; whereas, it was not significantly associated with either AFW or AFP in fat lines. At the same time, there were not any other significant epistatic components found in both generations or in both lines. Significant epistatic effects between these two SNPs found only in the lean lines could partly be due to the fact that the abdominal fat traits in these two experimental lines have been greatly modified by strong artificial selection. The results suggested that the epistasis mode may be different between the lean and fat chicken lines. Our results could be helpful in further understanding the genetic interaction between candidate genes contributing to phenotypic variation of abdominal fat content in broilers.
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Affiliation(s)
- Guo Hu
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
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116
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Bengtsson C, Blaho S, Saitton DB, Brickmann K, Broddefalk J, Davidsson O, Drmota T, Folmer R, Hallberg K, Hallén S, Hovland R, Isin E, Johannesson P, Kull B, Larsson LO, Löfgren L, Nilsson KE, Noeske T, Oakes N, Plowright AT, Schnecke V, Ståhlberg P, Sörme P, Wan H, Wellner E, Oster L. Design of small molecule inhibitors of acetyl-CoA carboxylase 1 and 2 showing reduction of hepatic malonyl-CoA levels in vivo in obese Zucker rats. Bioorg Med Chem 2011; 19:3039-53. [PMID: 21515056 DOI: 10.1016/j.bmc.2011.04.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 04/06/2011] [Accepted: 04/09/2011] [Indexed: 01/09/2023]
Abstract
Inhibition of acetyl-CoA carboxylases has the potential for modulating long chain fatty acid biosynthesis and mitochondrial fatty acid oxidation. Hybridization of weak inhibitors of ACC2 provided a novel, moderately potent but lipophilic series. Optimization led to compounds 33 and 37, which exhibit potent inhibition of human ACC2, 10-fold selectivity over inhibition of human ACC1, good physical and in vitro ADME properties and good bioavailability. X-ray crystallography has shown this series binding in the CT-domain of ACC2 and revealed two key hydrogen bonding interactions. Both 33 and 37 lower levels of hepatic malonyl-CoA in vivo in obese Zucker rats.
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117
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Abstract
Exercise, together with a low-energy diet, is the first-line treatment for type 2 diabetes type 2 diabetes . Exercise improves insulin sensitivity insulin sensitivity by increasing the number or function of muscle mitochondria mitochondria and the capacity for aerobic metabolism, all of which are low in many insulin-resistant subjects. Cannabinoid 1-receptor antagonists and β-adrenoceptor agonists improve insulin sensitivity in humans and promote fat oxidation in rodents independently of reduced food intake. Current drugs for the treatment of diabetes are not, however, noted for their ability to increase fat oxidation, although the thiazolidinediones increase the capacity for fat oxidation in skeletal muscle, whilst paradoxically increasing weight gain.There are a number of targets for anti-diabetic drugs that may improve insulin sensitivity insulin sensitivity by increasing the capacity for fat oxidation. Their mechanisms of action are linked, notably through AMP-activated protein kinase, adiponectin, and the sympathetic nervous system. If ligands for these targets have obvious acute thermogenic activity, it is often because they increase sympathetic activity. This promotes fuel mobilisation, as well as fuel oxidation. When thermogenesis thermogenesis is not obvious, researchers often argue that it has occurred by using the inappropriate device of treating animals for days or weeks until there is weight (mainly fat) loss and then expressing energy expenditure energy expenditure relative to body weight. In reality, thermogenesis may have occurred, but it is too small to detect, and this device distracts us from really appreciating why insulin sensitivity has improved. This is that by increasing fatty acid oxidation fatty acid oxidation more than fatty acid supply, drugs lower the concentrations of fatty acid metabolites that cause insulin resistance. Insulin sensitivity improves long before any anti-obesity effect can be detected.
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Affiliation(s)
- Jonathan R S Arch
- Clore Laboratory, University of Buckingham, Buckingham, MK18 1EG, UK
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118
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Lardenois A, Chalmel F, Barrionuevo F, Demougin P, Scherer G, Primig M. Profiling spermatogenic failure in adult testes bearing Sox9-deficient Sertoli cells identifies genes involved in feminization, inflammation and stress. Reprod Biol Endocrinol 2010; 8:154. [PMID: 21182756 PMCID: PMC3024295 DOI: 10.1186/1477-7827-8-154] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 12/23/2010] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Sox9 (Sry box containing gene 9) is a DNA-binding transcription factor involved in chondrocyte development and sex determination. The protein's absence in testicular Sertoli nurse cells has been shown to disrupt testicular function in adults but little is known at the genome-wide level about molecular events concomitant with testicular break-down. METHODS To determine the genome-wide effect on mRNA concentrations triggered by the absence of Sox9 in Sertoli cells we analysed adult testicular tissue from wild-type versus mutant mice with high-density oligonucleotide microarrays and integrated the output of this experiment with regulatory motif predictions and protein-protein network data. RESULTS We report the genome-wide mRNA signature of adult testes lacking Sox9 in Sertoli cells before and after the onset of late spermatogenic failure as compared to fertile controls. The GeneChip data integrated with evolutionarily conserved Sox9 DNA binding motifs and regulatory network data identified genes involved in feminization, stress response and inflammation. CONCLUSIONS Our results extend previous observations that genes required for female gonadogenesis are up-regulated in the absence of Sox9 in fetal Sertoli cells to the adult stage. Importantly, we identify gene networks involved in immunological processes and stress response which is reminiscent of a phenomenon occurring in a sub-group of infertile men. This suggests mice lacking Sox9 in their Sertoli cells to be a potentially useful model for adult human testicular failure.
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Affiliation(s)
- Aurélie Lardenois
- Inserm, U625, Université de Rennes 1, IFR140, Rennes, F-35042, France
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119
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Jump DB, Torres-Gonzalez M, Olson LK. Soraphen A, an inhibitor of acetyl CoA carboxylase activity, interferes with fatty acid elongation. Biochem Pharmacol 2010; 81:649-60. [PMID: 21184748 DOI: 10.1016/j.bcp.2010.12.014] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 12/08/2010] [Accepted: 12/10/2010] [Indexed: 02/06/2023]
Abstract
Acetyl CoA carboxylase (ACC1 and ACC2) generates malonyl CoA, a substrate for de novo lipogenesis (DNL) and an inhibitor of mitochondrial fatty acid β-oxidation (FAO). Malonyl CoA is also a substrate for microsomal fatty acid elongation, an important pathway for saturated (SFA), mono- (MUFA) and polyunsaturated fatty acid (PUFA) synthesis. Despite the interest in ACC as a target for obesity and cancer therapy, little attention has been given to the role ACC plays in long chain fatty acid synthesis. This report examines the effect of pharmacological inhibition of ACC on DNL and palmitate (16:0) and linoleate (18:2, n-6) metabolism in HepG2 and LnCap cells. The ACC inhibitor, soraphen A, lowers cellular malonyl CoA, attenuates DNL and the formation of fatty acid elongation products derived from exogenous fatty acids, i.e., 16:0 and 18:2, n-6; IC(50)∼5nM. Elevated expression of fatty acid elongases (Elovl5, Elovl6) or desaturases (FADS1, FADS2) failed to override the soraphen A effect on SFA, MUFA or PUFA synthesis. Inhibition of fatty acid elongation leads to the accumulation of 16- and 18-carbon unsaturated fatty acids derived from 16:0 and 18:2, n-6, respectively. Pharmacological inhibition of ACC activity will not only attenuate DNL and induce FAO, but will also attenuate the synthesis of very long chain saturated, mono- and polyunsaturated fatty acids.
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Affiliation(s)
- Donald B Jump
- Department of Nutrition and Exercise Sciences, The Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, United States.
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120
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Carpino PA, Goodwin B. Diabetes area participation analysis: a review of companies and targets described in the 2008 – 2010 patent literature. Expert Opin Ther Pat 2010; 20:1627-51. [DOI: 10.1517/13543776.2010.533171] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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121
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Strable MS, Ntambi JM. Genetic control of de novo lipogenesis: role in diet-induced obesity. Crit Rev Biochem Mol Biol 2010; 45:199-214. [PMID: 20218765 DOI: 10.3109/10409231003667500] [Citation(s) in RCA: 325] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
De novo lipogenesis (DNL) is a complex yet highly regulated metabolic pathway, and transcription factors such as liver X receptor (LXR), sterol regulatory element-binding protein-1c (SREBP-1c), and carbohydrate response element binding protein (ChREBP) exert significant control over the de novo synthesis of fatty acids. An increase in de novo lipogenesis (DNL) is an important contributor to increased fat mass, while a reduction in lipogenesis may be protective against the development of obesity. In this review, we explore fatty acid synthesis in the context of new insights gleaned from global and tissue-specific gene knockout mouse models of enzymes involved in fatty acid synthesis, namely acetyl-CoA carboxylase, fatty acid synthase, fatty acid elongase 6, and stearoyl-CoA desaturase 1. A disruption in fatty acid synthesis, induced by the deficiency of any one of these enzymes, affects lipid metabolism and in some cases may protect against obesity in a tissue and gene-specific manner, as discussed in detail in this review.
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Affiliation(s)
- Maggie S Strable
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI, USA
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122
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Wai T, Ao A, Zhang X, Cyr D, Dufort D, Shoubridge EA. The role of mitochondrial DNA copy number in mammalian fertility. Biol Reprod 2010; 83:52-62. [PMID: 20130269 PMCID: PMC2888963 DOI: 10.1095/biolreprod.109.080887] [Citation(s) in RCA: 293] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 09/15/2009] [Accepted: 01/13/2010] [Indexed: 12/31/2022] Open
Abstract
Mammalian mitochondrial DNA (mtDNA) is a small, maternally inherited genome that codes for 13 essential proteins in the respiratory chain. Mature oocytes contain more than 150 000 copies of mtDNA, at least an order of magnitude greater than the number in most somatic cells, but sperm contain only approximately 100 copies. Mitochondrial oxidative phosphorylation has been suggested to be an important determinant of oocyte quality and sperm motility; however, the functional significance of the high mtDNA copy number in oocytes, and of the low copy number in sperm, remains unclear. To investigate the effects of mtDNA copy number on fertility, we genetically manipulated mtDNA copy number in the mouse by deleting one copy of Tfam, an essential component of the mitochondrial nucleoid, at different stages of germline development. We show that males can tolerate at least a threefold reduction in mtDNA copy number in their sperm without impaired fertility, and in fact, they preferentially transmit a deleted Tfam allele. Surprisingly, oocytes with as few as 4000 copies of mtDNA can be fertilized and progress normally through preimplantation development to the blastocyst stage. The mature oocyte, however, has a critical postimplantation developmental threshold of 40 000-50 000 copies of mtDNA in the mature oocyte. These observations suggest that the high mtDNA copy number in the mature oocyte is a genetic device designed to distribute mitochondria and mtDNAs to the cells of the early postimplantation embryo before mitochondrial biogenesis and mtDNA replication resumes, whereas down-regulation of mtDNA copy number is important for normal sperm function.
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Affiliation(s)
- Timothy Wai
- Montreal Neurological Institute and Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Asangla Ao
- Departments of Obstetrics and Gynecology and Human Genetics and Division of Experimental Medicine, McGill University Health Center, Royal Victoria Hospital, Montreal, Quebec, Canada
| | - Xiaoyun Zhang
- Departments of Obstetrics and Gynecology and Human Genetics and Division of Experimental Medicine, McGill University Health Center, Royal Victoria Hospital, Montreal, Quebec, Canada
| | - Daniel Cyr
- INRS-Instiut Armand Frappier, Université du Québec, Laval, Québec, Canada
| | - Daniel Dufort
- Departments of Obstetrics and Gynecology and Human Genetics and Division of Experimental Medicine, McGill University Health Center, Royal Victoria Hospital, Montreal, Quebec, Canada
| | - Eric A. Shoubridge
- Montreal Neurological Institute and Department of Human Genetics, McGill University, Montreal, Quebec, Canada
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123
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Landrock D, Atshaves BP, McIntosh AL, Landrock KK, Schroeder F, Kier AB. Acyl-CoA binding protein gene ablation induces pre-implantation embryonic lethality in mice. Lipids 2010; 45:567-80. [PMID: 20559753 PMCID: PMC2997683 DOI: 10.1007/s11745-010-3437-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 05/29/2010] [Indexed: 11/26/2022]
Abstract
Unique among the intracellular lipid binding proteins, acyl-CoA binding protein (ACBP) exclusively binds long-chain fatty acyl-CoAs (LCFA-CoAs). To test if ACBP is an essential protein in mammals, the ACBP gene was ablated by homologous recombination in mice. While ACBP heterozygotes appeared phenotypically normal, intercrossing of the heterozygotes did not produce any live homozygous deficient (null) ACBP((-/-)) pups. Heterozygous and wild type embryos were detected at all post-implantation stages, but no homozygous ACBP-null embryos were obtained-suggesting that an embryonic lethality occurred at a pre-implantation stage of development, or that embryos never formed. While ACBP-null embryos were not detected at any blastocyst stage, ACBP-null embryos were detected at the morula (8-cell), cleavage (2-cell), and zygote (1-cell) pre-implantation stages. Two other LCFA-CoA binding proteins, sterol carrier protein-2 (SCP-2) and sterol carrier protein-x (SCP-x) were significantly upregulated at these stages. These findings demonstrate for the first time that ACBP is an essential protein required for embryonic development and its loss of function may be initially compensated by concomitant upregulation of two other LCFA-CoA binding proteins, but only at the earliest pre-implantation stages. The fact that ACBP is the first known intracellular lipid binding protein whose deletion results in embryonic lethality suggests its vital importance in mammals.
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Affiliation(s)
- Danilo Landrock
- Department of Pathobiology, Texas A&M University, TAMU 4467, College Station, TX 77843-4467, USA
| | - Barbara P. Atshaves
- Department of Physiology and Pharmacology, Texas A&M University, TAMU 4466, College Station, TX 77843-4466, USA
| | - Avery L. McIntosh
- Department of Physiology and Pharmacology, Texas A&M University, TAMU 4466, College Station, TX 77843-4466, USA
| | - Kerstin K. Landrock
- Department of Physiology and Pharmacology, Texas A&M University, TAMU 4466, College Station, TX 77843-4466, USA
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, TAMU 4466, College Station, TX 77843-4466, USA
| | - Ann B. Kier
- Department of Pathobiology, Texas A&M University, TAMU 4467, College Station, TX 77843-4467, USA
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124
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Tripathy S, Torres-Gonzalez M, Jump DB. Elevated hepatic fatty acid elongase-5 activity corrects dietary fat-induced hyperglycemia in obese C57BL/6J mice. J Lipid Res 2010; 51:2642-54. [PMID: 20488798 DOI: 10.1194/jlr.m006080] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Elevated hepatic fatty acid elongase-5 (Elovl5) activity lowers blood glucose in fasted chow-fed C57BL/6J mice. As high-fat diets induce hyperglycemia and suppress hepatic Elovl5 activity, we tested the hypothesis that elevated hepatic Elovl5 expression attenuates hyperglycemia in high-fat-diet-induced obese mice. Increasing hepatic Elovl5 activity by a recombinant adenoviral approach restored blood glucose and insulin, HOMA-IR, and glucose tolerance to normal values in obese mice. Elevated Elovl5 activity increased hepatic content of Elovl5 products (20:3,n-6, 22:4,n-6) and suppressed levels of enzymes (Pck1, G6Pc) and transcription factors (FoxO1 and PGC1alpha, but not CRTC2) involved in gluconeogenesis. Effects of Elovl5 on FoxO1 nuclear abundance correlated with increased phosphorylation of FoxO1, Akt, and the catalytic unit of PP2A, as well as a decline in cellular abundance of TRB3. Such changes are mechanistically linked to the regulation of FoxO1 nuclear abundance and gluconeogenesis. These results show that Elovl5 activity impacts the hepatic abundance and phosphorylation status of multiple proteins involved in gluconeogenesis. Our findings establish a link between fatty acid elongation and hepatic glucose metabolism and suggest a role for regulators of Elovl5 activity in the treatment of diet-induced hyperglycemia.
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Affiliation(s)
- Sasmita Tripathy
- Department of Nutrition and Exercise Sciences, The Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA
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125
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Recombinant yeast screen for new inhibitors of human acetyl-CoA carboxylase 2 identifies potential drugs to treat obesity. Proc Natl Acad Sci U S A 2010; 107:9093-8. [PMID: 20439761 DOI: 10.1073/pnas.1003721107] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Acetyl-CoA carboxylase (ACC) is a key enzyme of fatty acid metabolism with multiple isozymes often expressed in different eukaryotic cellular compartments. ACC-made malonyl-CoA serves as a precursor for fatty acids; it also regulates fatty acid oxidation and feeding behavior in animals. ACC provides an important target for new drugs to treat human diseases. We have developed an inexpensive nonradioactive high-throughput screening system to identify new ACC inhibitors. The screen uses yeast gene-replacement strains depending for growth on cloned human ACC1 and ACC2. In "proof of concept" experiments, growth of such strains was inhibited by compounds known to target human ACCs. The screen is sensitive and robust. Medium-size chemical libraries yielded new specific inhibitors of human ACC2. The target of the best of these inhibitors was confirmed with in vitro enzymatic assays. This compound is a new drug chemotype inhibiting human ACC2 with 2.8 muM IC(50) and having no effect on human ACC1 at 100 muM.
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126
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Schreurs M, Kuipers F, van der Leij FR. Regulatory enzymes of mitochondrial beta-oxidation as targets for treatment of the metabolic syndrome. Obes Rev 2010; 11:380-8. [PMID: 19694967 DOI: 10.1111/j.1467-789x.2009.00642.x] [Citation(s) in RCA: 214] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Insulin sensitizers like metformin generally act through pathways triggered by adenosine monophosphate-activated protein kinase. Carnitine palmitoyltransferase 1 (CPT1) controls mitochondrial beta-oxidation and is inhibited by malonyl-CoA, the product of acetyl-CoA carboxylase (ACC). The adenosine monophosphate-activated protein kinase-ACC-CPT1 axis tightly regulates mitochondrial long-chain fatty acid oxidation. Evidence indicates that ACC2, the isoform located in close proximity to CPT1, is the major regulator of CPT1 activity. ACC2 as well as CPT1 are therefore potential targets to treat components of the metabolic syndrome such as obesity and insulin resistance. Reversible inhibitors of the liver isoform of CPT1, developed to prevent ketoacidosis and hyperglycemia, have been found to be associated with side effects like hepatic steatosis. However, stimulation of systemic CPT1 activity may be an attractive means to accelerate peripheral fatty acid oxidation and hence improve insulin sensitivity. Stimulation of CPT1 can be achieved by elimination or inhibition of ACC2 activity and through activating transcription factors like peroxisome proliferator-activated receptors and their protein partners. The latter leads to enhanced CPT1 gene expression. Recent developments are discussed, including a recently identified CPT1 isoform, i.e. CPT1C. This protein is highly expressed in the brain and may provide a target for new tools to prevent obesity.
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Affiliation(s)
- M Schreurs
- Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
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127
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Lopaschuk GD, Ussher JR, Jaswal JS. Targeting intermediary metabolism in the hypothalamus as a mechanism to regulate appetite. Pharmacol Rev 2010; 62:237-64. [PMID: 20392806 DOI: 10.1124/pr.109.002428] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The central nervous system mediates energy balance (energy intake and energy expenditure) in the body; the hypothalamus has a key role in this process. Recent evidence has demonstrated an important role for hypothalamic malonyl CoA in mediating energy balance. Malonyl CoA is generated by the carboxylation of acetyl CoA by acetyl CoA carboxylase and is then either incorporated into long-chain fatty acids by fatty acid synthase, or converted back to acetyl-CoA by malonyl CoA decarboxylase. Increased hypothalamic malonyl CoA is an indicator of energy surplus, resulting in a decrease in food intake and an increase in energy expenditure. In contrast, a decrease in hypothalamic malonyl CoA signals an energy deficit, resulting in an increased appetite and a decrease in body energy expenditure. A number of hormonal and neural orexigenic and anorexigenic signaling pathways have now been shown to be associated with changes in malonyl CoA levels in the arcuate nucleus (ARC) of the hypothalamus. Despite compelling evidence that malonyl CoA is an important mediator in the hypothalamic ARC control of food intake and regulation of energy balance, the mechanism(s) by which this occurs has not been established. Malonyl CoA inhibits carnitine palmitoyltransferase-1 (CPT-1), and it has been proposed that the substrate of CPT-1, long-chain acyl CoA(s), may act as a mediator(s) of appetite and energy balance. However, recent evidence has challenged the role of long-chain acyl CoA(s) in this process, as well as the involvement of CPT-1 in hypothalamic malonyl CoA signaling. A better understanding of how malonyl CoA regulates energy balance should provide novel approaches to targeting intermediary metabolism in the hypothalamus as a mechanism to control appetite and body weight. Here, we review the data supporting an important role for malonyl CoA in mediating hypothalamic control of energy balance, and recent evidence suggesting that targeting malonyl CoA synthesis or degradation may be a novel approach to favorably modify appetite and weight gain.
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Affiliation(s)
- Gary D Lopaschuk
- 423 Heritage Medical Research Center, University of Alberta, Edmonton, Canada T6G2S2.
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128
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Tian J, Wang S, Wang Q, Leng L, Hu X, Li H. A single nucleotide polymorphism of chicken acetyl-CoA carboxylase A gene associated with fatness traits. Anim Biotechnol 2010; 21:42-50. [PMID: 20024786 DOI: 10.1080/10495390903347009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Acetyl-CoA carboxylase alpha (ACCalpha) is a major rate-limiting enzyme in the biogenesis of long-chain fatty acids. It can catalyze the carboxylation of acetyl-CoA to form malonyl-CoA that plays a key role in the regulation of fatty acid metabolism. The objective of the present study was to investigate the associations of ACCalpha gene polymorphisms with chicken growth and body composition traits. The Northeast Agricultural University broiler lines divergently selected for abdominal fat content and the Northeast Agricultural University F(2) Resource Population were used in the current study. Body weight and body composition traits were measured in the aforementioned two populations. A synonymous mutation was detected in the exon 19 region of ACCalpha gene, then polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was developed to genotype all the individuals derived from the aforementioned populations. Association analysis revealed that the polymorphism was associated with abdominal fat weight and percentage of abdominal fat in the two populations. The results suggested that ACCalpha gene could be a candidate locus or linked to a major gene that affects abdominal fat content in the chicken.
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Affiliation(s)
- Jianwei Tian
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
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129
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Furuta E, Okuda H, Kobayashi A, Watabe K. Metabolic genes in cancer: their roles in tumor progression and clinical implications. Biochim Biophys Acta Rev Cancer 2010; 1805:141-52. [PMID: 20122995 DOI: 10.1016/j.bbcan.2010.01.005] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2009] [Revised: 01/11/2010] [Accepted: 01/24/2010] [Indexed: 12/12/2022]
Abstract
Re-programming of metabolic pathways is a hallmark of physiological changes in cancer cells. The expression of certain genes that directly control the rate of key metabolic pathways including glycolysis, lipogenesis and nucleotide synthesis are drastically altered at different stages of tumor progression. These alterations are generally considered as an adaptation of tumor cells; however, they also contribute to the progression of tumor cells to become more aggressive phenotypes. This review summarizes the recent information about the mechanistic link of these genes to oncogenesis and their potential utility as diagnostic markers as well as for therapeutic targets. We particularly focus on three groups of genes; GLUT1, G6PD, TKTL1 and PGI/AMF in glycolytic pathway, ACLY, ACC1 and FAS in lipogenesis and RRM2, p53R2 and TYMS for nucleotide synthesis. All these genes are highly up-regulated in a variety of tumor cells in cancer patients, and they play active roles in tumor progression rather than expressing merely as a consequence of phenotypic change of the cancer cells. Molecular dissection of their orchestrated networks and understanding the exact mechanism of their expression will provide a window of opportunity to target these genes for specific cancer therapy. We also reviewed existing database of gene microarray to validate the utility of these genes for cancer diagnosis.
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Affiliation(s)
- Eiji Furuta
- Department of Medical Microbiology and Immunology, Southern Illinois University School of Medicine, Springfield, Illinois, USA
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130
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Recent Advances in Acetyl-CoA Carboxylase Inhibitors. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2010. [DOI: 10.1016/s0065-7743(10)45006-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
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131
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Iwanaga T, Kuchiiwa T, Saito M. Histochemical demonstration of monocarboxylate transporters in mouse brown adipose tissue. ACTA ACUST UNITED AC 2009; 30:217-25. [PMID: 19729852 DOI: 10.2220/biomedres.30.217] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Proton-coupled monocarboxylate transporters (MCTs) are essential for the transport of lactate, ketone bodies, and other monocarboxylates through the plasma membrane. The present immunohistochemical study aimed to examine the expression of MCTs in the brown adipose tissue (BAT) of mice. An intense immunoreactivity for MCT1 was found in the plasma membrane of brown adipose cells at light and electron microscopic levels but not in white adipose cells. The expression of MCT1 in BAT was confirmed by Western blot and in situ hybridization analyses. In fetuses (E17.5) and neonates, the MCT1 mRNA expression of BAT was abundant and appeared more intense than that in adult animals. These results, together with the intense expression of CD147 (a functional partner of MCTs) and acetyl-CoA carboxylase-2 (a component of fatty acid oxidation) in perinatal periods, suggest the involvement of MCT1 in the uptake of monocarboxylates from the circulation for thermogenesis rather than lipogenesis.
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132
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Schreurs M, van Dijk TH, Gerding A, Havinga R, Reijngoud DJ, Kuipers F. Soraphen, an inhibitor of the acetyl-CoA carboxylase system, improves peripheral insulin sensitivity in mice fed a high-fat diet. Diabetes Obes Metab 2009; 11:987-91. [PMID: 19519866 DOI: 10.1111/j.1463-1326.2009.01078.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM Inhibition of the acetyl-CoA carboxylase (ACC) system, consisting of the isozymes ACC1 and ACC2, may be beneficial for treatment of insulin resistance and/or obesity by interfering with de novo lipogenesis and beta-oxidation. We have evaluated effects of pharmacological inhibition of ACC by soraphen (SP) on high fat (HF) diet-induced insulin resistance in mice. METHOD Male C57Bl6/J mice were fed control chow, a HF diet or a HF diet supplemented with SP (50 or 100 mg/kg/day). RESULTS Body weight gain and total body fat content of SP-treated animals were significantly reduced compared with HF-fed mice. Fractional synthesis of palmitate was significantly reduced in mice treated with SP, indicative for ACC1 inhibition. Plasma beta-hydroxybutyrate levels were significantly elevated by SP, reflecting simultaneous inhibition of ACC2 activity. Mice treated with SP showed improved peripheral insulin sensitivity, as assessed by hyperinsulinaemic euglycaemic clamps. CONCLUSION Pharmacological inhibition of the ACC system is of potential use for treatment of key components of the metabolic syndrome.
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Affiliation(s)
- M Schreurs
- Department of Pediatrics, Center for Liver Digestive and Metabolic Diseases, University Medical Center Groningen, University of Groningen, PO Box 30.001, Groningen 9700 RB, The Netherlands.
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133
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Haque TS, Liang N, Golla R, Seethala R, Ma Z, Ewing WR, Cooper CB, Pelleymounter MA, Poss MA, Cheng D. Potent biphenyl- and 3-phenyl pyridine-based inhibitors of acetyl-CoA carboxylase. Bioorg Med Chem Lett 2009; 19:5872-6. [DOI: 10.1016/j.bmcl.2009.08.077] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 08/20/2009] [Accepted: 08/21/2009] [Indexed: 10/20/2022]
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134
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Lipid oversupply, selective insulin resistance, and lipotoxicity: molecular mechanisms. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1801:252-65. [PMID: 19796706 DOI: 10.1016/j.bbalip.2009.09.015] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 09/16/2009] [Accepted: 09/17/2009] [Indexed: 12/15/2022]
Abstract
The accumulation of fat in tissues not suited for lipid storage has deleterious consequences on organ function, leading to cellular damage that underlies diabetes, heart disease, and hypertension. To combat these lipotoxic events, several therapeutics improve insulin sensitivity and/or ameliorate features of metabolic disease by limiting the inappropriate deposition of fat in peripheral tissues (i.e. thiazolidinediones, metformin, and statins). Recent advances in genomics and lipidomics have accelerated progress towards understanding the pathogenic events associated with the excessive production, underutilization, or inefficient storage of fat. Herein we review studies applying pharmacological or genetic strategies to manipulate the expression or activity of enzymes controlling lipid deposition, in order to gain a clearer understanding of the molecular mechanisms by which fatty acids contribute to metabolic disease.
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135
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aP2-Cre-mediated inactivation of acetyl-CoA carboxylase 1 causes growth retardation and reduced lipid accumulation in adipose tissues. Proc Natl Acad Sci U S A 2009; 106:17576-81. [PMID: 19805143 DOI: 10.1073/pnas.0909055106] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Adipose tissue is one of the major sites for fatty acid synthesis and lipid storage. We generated adipose (fat)-specific ACC1 knockout (FACC1KO) mice using the aP2-Cre/loxP system. FACC1KO mice showed prenatal growth retardation; after weaning, however, their weight gain was comparable to that of wild-type (WT) mice on a normal diet. Under lipogenic conditions of fasting/re-feeding a fat-free diet, lipid accumulation in adipose tissues of FACC1KO mice was significantly decreased; this is consistent with a 50-66% reduction in the ACC activity in these tissues compared with that of WT mice. Surprisingly, FACC1KO mice manifested skeletal growth retardation phenotype accompanied by decreased chondrocyte proliferation in the growth plate and lower trabecular bone density. In addition, there was about a 30% decrease in serum insulin-like growth factor I (IGF1), and while the serum leptin level was decreased by about 50%, it did not counteract the osteopenic effects of IGF1 on the bone. Fatty acid analyses of mutant bone lipids revealed relatively higher levels of C18:2n-6 and C18:3n-3 and lower levels of their elongation C20 homologs than that of WT cohorts, leading to lower levels of C20 homologs and bone development. Moreover, aP2-Cre-mediated ACC1 inactivation in bone tissue led to a decreased number of osteoblasts but not of osteoclasts. The downregulation of ACC1 on osteoblastogenesis may be the cause for the osteopenia phenotype of FACC1KO bone homeostasis.
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136
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Chari M, Lam C, Lam T. Hypothalamic Fatty Acid Sensing in the Normal and Disease States. Front Neurosci 2009. [DOI: 10.1201/9781420067767-c20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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137
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Hou TY, Ward SM, Murad JM, Watson NP, Israel MA, Duffield GE. ID2 (inhibitor of DNA binding 2) is a rhythmically expressed transcriptional repressor required for circadian clock output in mouse liver. J Biol Chem 2009; 284:31735-45. [PMID: 19740747 DOI: 10.1074/jbc.m109.013961] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Id2 is a helix-loop-helix transcription factor gene expressed in a circadian manner in multiple tissues with a phase-locked relationship with canonical clock genes. Our previous studies have identified circadian phenotypes in Id2 null mice, including enhanced photo-entrainment and disruption of activity rhythms, and have demonstrated a potent inhibitory effect of ID proteins upon CLOCK-BMAL1 transactivation of clock gene and clock-controlled gene activity. We have now begun to explore the potential role that ID2 may play in specifically regulating clock output. Here we show that ID2 protein is rhythmically expressed in mouse liver. Time-of-day-specific liver gene expression in Id2(+/+) and Id2(-/-) mice under circadian conditions was studied using DNA microarray analysis, identifying 651 differentially expressed genes, including a subset of 318 genes deemed rhythmically expressed in other studies. Examination of individual time courses reveals that these genes are dysregulated in a highly time-specific manner. A cohort of different functional groups were identified, including genes associated with glucose and lipid metabolism, e.g. serum protein Igfbp1 and lipoprotein lipase. We also reveal that the Id2(-/-) mice show a reduction in lipid storage in the liver and white adipose tissue, suggesting that disruption of normal circadian activity of components of lipid metabolism can result in overt physiological alterations. These data reveal a role for the transcriptional repressor ID2 as a circadian output regulator in the periphery.
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Affiliation(s)
- Tim Y Hou
- Department of Biological Sciences, Galvin Life Science Center, University of Notre Dame, Notre Dame, Indiana 46556, USA
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138
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Leptin contributes to the adaptive responses of mice to high-fat diet intake through suppressing the lipogenic pathway. PLoS One 2009; 4:e6884. [PMID: 19727392 PMCID: PMC2731220 DOI: 10.1371/journal.pone.0006884] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Accepted: 08/05/2009] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Leptin is an adipocyte-derived hormone that plays a critical role in energy homeostasis and lipid metabolism. Overnutrition-associated obesity is known to be accompanied by hyperleptinemia. However, the physiological actions of leptin in the metabolic responses to high-fat diet (HFD) intake remain to be completely elucidated. Here we characterized the metabolic features of mice fed high-fat diets and investigated the impact of leptin upon the lipogenic program which was found to be suppressed by HFD feeding through a proteomics approach. RESULTS When maintained on two types of high-fat diets for up to 16 weeks, mice with a higher fat intake exhibited increased body fat accumulation at a greater pace, developing more severely impaired glucose tolerance. Notably, HFD feeding at 4 weeks elicited the onset of marked hyperleptinemia, prior to the occurrence of apparent insulin resistance and hyperinsulinemia. Proteomic analysis revealed dramatically decreased expression of lipogenic enzymes in the white adipose tissue (WAT) from HFD-fed mice, including ATP-citrate lyase (ACL) and fatty acid synthase (FAS). The expression of ACL and FAS in the liver was similarly suppressed in response to HFD feeding. By contrast, HFD-induced downregulation of hepatic ACL and FAS was significantly attenuated in leptin receptor-deficient db/db mice. Furthermore, in the liver and WAT of wild type animals, intraperitoneal leptin administration was able to directly suppress the expression of these two lipogenic enzymes, accompanied by reduced triglyceride levels both in the liver and serum. CONCLUSIONS These results suggest that leptin contributes to the metabolic responses in adaptation to overnutrition through suppressing the expression of lipogenic enzymes, and that the lipogenic pathway represents a key targeted peripheral component in exerting leptin's liporegulatory actions.
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139
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Chen CH, Chang MY, Lin YS, Lin DG, Chen SW, Chao PM. A herbal extract with acetyl-coenzyme A carboxylase inhibitory activity and its potential for treating metabolic syndrome. Metabolism 2009; 58:1297-305. [PMID: 19500808 DOI: 10.1016/j.metabol.2009.04.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 04/17/2009] [Accepted: 04/20/2009] [Indexed: 02/09/2023]
Abstract
Acetyl-coenzyme A carboxylase (ACC) plays a crucial role in fatty acid metabolism, and its inhibition is an effective approach for treating metabolic syndrome. Partially purified ACC from rat liver was used to screen herbs commonly used in Taiwanese folk medicine for ACC inhibitory effects. An ethanol extract of Polygonum hypoleucum Ohwi (EP), the Taiwan tuber fleece flower, was found to have the highest inhibitory activity (half-maximal inhibitory concentration = 30 microg/mL). We then tested the physiologic effects of EP using high-fat (HF) diet-fed C57BL/6J mice. After 4 weeks, body weight and levels of blood glucose, insulin, triacylglycerol, total cholesterol, and leptin were significantly reduced (P < .05) in mice fed a 3% EP-containing HF diet. The EP also improved the glucose tolerance and insulin sensitivity of HF diet-fed mice. In addition, EP at concentrations of 0.0725 and 0.145 mg/mL (2.5- and 5-fold higher than the half-maximal inhibitory concentration) was also effective in decreasing ACC and fatty acid synthase activity and the triacylglycerol content of HepG2 cells incubated in high-glucose (30 mmol/L) medium. These results show that EP, acting by inhibiting ACC activity, is effective in alleviating the symptoms associated with metabolic disease.
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Affiliation(s)
- Chi-Hua Chen
- Food Industry Research Development Institute, Hsinchu 300, Taiwan
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140
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Abstract
In 1963, Lancet published a paper by Randle et al. that proposed a "glucose-fatty acid cycle" to describe fuel flux between and fuel selection by tissues. The original biochemical mechanism explained the inhibition of glucose oxidation by fatty acids. Since then, the principle has been confirmed by many investigators. At the same time, many new mechanisms controlling the utilization of glucose and fatty acids have been discovered. Here, we review the known short- and long-term mechanisms involved in the control of glucose and fatty acid utilization at the cytoplasmic and mitochondrial level in mammalian muscle and liver under normal and pathophysiological conditions. They include allosteric control, reversible phosphorylation, and the expression of key enzymes. However, the complexity is formidable. We suggest that not all chapters of the Randle cycle have been written.
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Affiliation(s)
- Louis Hue
- Université Catholique de Louvain and de Duve Institute, Hormone and Metabolic Research Unit, Brussels, Belgium.
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141
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Abstract
The function and survival of all organisms is dependent on the dynamic control of energy metabolism, when energy demand is matched to energy supply. The AMP-activated protein kinase (AMPK) alphabetagamma heterotrimer has emerged as an important integrator of signals that control energy balance through the regulation of multiple biochemical pathways in all eukaryotes. In this review, we begin with the discovery of the AMPK family and discuss the recent structural studies that have revealed the molecular basis for AMP binding to the enzyme's gamma subunit. AMPK's regulation involves autoinhibitory features and phosphorylation of both the catalytic alpha subunit and the beta-targeting subunit. We review the role of AMPK at the cellular level through examination of its many substrates and discuss how it controls cellular energy balance. We look at how AMPK integrates stress responses such as exercise as well as nutrient and hormonal signals to control food intake, energy expenditure, and substrate utilization at the whole body level. Lastly, we review the possible role of AMPK in multiple common diseases and the role of the new age of drugs targeting AMPK signaling.
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Affiliation(s)
- Gregory R Steinberg
- Protein Chemistry and Metabolism, St. Vincent's Institute of Medical Research, University of Melbourne, Fitzroy, Victoria, Australia.
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142
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Wang C, Yan R, Luo D, Watabe K, Liao DF, Cao D. Aldo-keto reductase family 1 member B10 promotes cell survival by regulating lipid synthesis and eliminating carbonyls. J Biol Chem 2009; 284:26742-8. [PMID: 19643728 DOI: 10.1074/jbc.m109.022897] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Aldo-keto reductase family 1 member B10 (AKR1B10) is primarily expressed in the normal human colon and small intestine but overexpressed in liver and lung cancer. Our previous studies have shown that AKR1B10 mediates the ubiquitin-dependent degradation of acetyl-CoA carboxylase-alpha. In this study, we demonstrate that AKR1B10 is critical to cell survival. In human colon carcinoma cells (HCT-8) and lung carcinoma cells (NCI-H460), small-interfering RNA-induced AKR1B10 silencing resulted in caspase-3-mediated apoptosis. In these cells, the total and subspecies of cellular lipids, particularly of phospholipids, were decreased by more than 50%, concomitant with 2-3-fold increase in reactive oxygen species, mitochondrial cytochrome c efflux, and caspase-3 cleavage. AKR1B10 silencing also increased the levels of alpha,beta-unsaturated carbonyls, leading to the 2-3-fold increase of cellular lipid peroxides. Supplementing the HCT-8 cells with palmitic acid (80 mum), the end product of fatty acid synthesis, partially rescued the apoptosis induced by AKR1B10 silencing, whereas exposing the HCT-8 cells to epalrestat, an AKR1B10 inhibitor, led to more than 2-fold elevation of the intracellular lipid peroxides, resulting in apoptosis. These data suggest that AKR1B10 affects cell survival through modulating lipid synthesis, mitochondrial function, and oxidative status, as well as carbonyl levels, being an important cell survival protein.
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Affiliation(s)
- Chun Wang
- Department of Medical Microbiology, SimmonsCooper Cancer Institute, Southern Illinois University School of Medicine, Springfield, Illinois 62702, USA
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143
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Finley LW, Haigis MC. The coordination of nuclear and mitochondrial communication during aging and calorie restriction. Ageing Res Rev 2009; 8:173-88. [PMID: 19491041 DOI: 10.1016/j.arr.2009.03.003] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 02/27/2009] [Accepted: 03/04/2009] [Indexed: 12/24/2022]
Abstract
Mitochondria are dynamic organelles that integrate environmental signals to regulate energy production, apoptosis and Ca(2+) homeostasis. Not surprisingly, mitochondrial dysfunction is associated with aging and the pathologies observed in age-related diseases. The vast majority of mitochondrial proteins are encoded in the nuclear genome, and so communication between the nucleus and mitochondria is essential for maintenance of appropriate mitochondrial function. Several proteins have emerged as major regulators of mitochondrial gene expression, capable of increasing transcription of mitochondrial genes in response to the physiological demands of the cell. In this review, we will focus on PGC-1alpha, SIRT1, AMPK and mTOR and discuss how these proteins regulate mitochondrial function and their potential involvement in aging, calorie restriction and age-related disease. We will also discuss the pathways through which mitochondria signal to the nucleus. Although such retrograde signaling is not well studied in mammals, there is growing evidence to suggest that it may be an important area for future aging research. Greater understanding of the mechanisms by which mitochondria and the nucleus communicate will facilitate efforts to slow or reverse the mitochondrial dysfunction that occurs during aging.
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144
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Milanski M, Souza KLA, Reis SRL, Feres NH, de Souza LMI, Arantes VC, Carneiro EM, Boschero AC, Reis MAB, Latorraca MQ. Soybean diet modulates acetyl-coenzyme A carboxylase expression in livers of rats recovering from early-life malnutrition. Nutrition 2009; 25:774-81. [PMID: 19251398 DOI: 10.1016/j.nut.2008.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2008] [Revised: 10/25/2008] [Accepted: 12/08/2008] [Indexed: 01/14/2023]
Abstract
OBJECTIVE The present study evaluated the effect of nutritional recovery with a soybean diet on the gene and protein expressions and protein phosphorylation of several enzymes and transcription factors involved in hepatic lipid metabolism. METHODS Rats from mothers fed with 17% or 6% protein (casein) during pregnancy and lactation were maintained with a 17% casein (CC and LC groups) or soybean (CS and LS groups) diet and with a 6% casein (LL group) diet until 90 d of life. RESULTS The soybean diet enhanced serum insulin levels but decreased body and liver weights and hepatic lipid and glycogen concentrations. Liver peroxisome proliferator receptor-alpha mRNA abundance was higher in the LS and CS groups than in the LC and CC groups, but the protein content was similar in all groups. Hepatic acetyl-coenzyme A carboxylase (ACC)-alpha and ACCbeta mRNA expression was markedly lower in the LS and CS rats than in the LC and CC rats. ACC protein expression was lower in the CS group than in the CC, LC, and LS groups. Phospho-[Ser(79)]2-ACC content was similar in the CS, LC, and LS groups and lower than the CC group. In the CS rats this reduction paralleled the decrease in total ACC protein. Messenger RNA and protein expression of sterol regulatory element-binding protein 1c, adenosine monophosphate-activated protein kinase, and phospho-[Thr(172)]-adenosine monophosphate-activated protein kinase was not modified by the soybean diet. CONCLUSION Thus, the soybean diet reduced the liver lipid concentration through downregulation of the ACC gene and protein expressions rather than by phosphorylation status, which possibly resulted in decreased lipogenesis and increased beta-oxidation.
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145
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Corbett JW. Review of recent acetyl-CoA carboxylase inhibitor patents: mid-2007 – 2008. Expert Opin Ther Pat 2009; 19:943-56. [DOI: 10.1517/13543770902862180] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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146
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Wang C, Xu C, Sun M, Luo D, Liao DF, Cao D. Acetyl-CoA carboxylase-alpha inhibitor TOFA induces human cancer cell apoptosis. Biochem Biophys Res Commun 2009; 385:302-6. [PMID: 19450551 DOI: 10.1016/j.bbrc.2009.05.045] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2009] [Accepted: 05/12/2009] [Indexed: 12/16/2022]
Abstract
Acetyl-CoA carboxylase-alpha (ACCA) is a rate-limiting enzyme in long chain fatty acid synthesis, playing a critical role in cellular energy storage and lipid synthesis. ACCA is upregulated in multiple types of human cancers and small interfering RNA-mediated ACCA silencing in human breast and prostate cancer cells results in oxidative stress and apoptosis. This study reports for the first time that TOFA (5-tetradecyloxy-2-furoic acid), an allosteric inhibitor of ACCA, is cytotoxic to lung cancer cells NCI-H460 and colon carcinoma cells HCT-8 and HCT-15, with an IC(50) at approximately 5.0, 5.0, and 4.5 microg/ml, respectively. TOFA at 1.0-20.0 microg/ml effectively blocked fatty acid synthesis and induced cell death in a dose-dependent manner. The cell death was characterized with PARP cleavage, DNA fragmentation, and annexin-V staining, all of which are the features of the apoptosis. Supplementing simultaneously the cells with palmitic acids (100 microM), the end-products of the fatty acid synthesis pathway, prevented the apoptosis induced by TOFA. Taken together, these data suggest that TOFA is a potent cytotoxic agent to lung and colon cancer cells, inducing apoptosis through disturbing their fatty acid synthesis.
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Affiliation(s)
- Chun Wang
- School of Pharmaceutical Sciences, Central South University, Changsha 410083, China
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147
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Madauss KP, Burkhart WA, Consler TG, Cowan DJ, Gottschalk WK, Miller AB, Short SA, Tran TB, Williams SP. The human ACC2 CT-domain C-terminus is required for full functionality and has a novel twist. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2009; 65:449-61. [PMID: 19390150 PMCID: PMC2725780 DOI: 10.1107/s0907444909008014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Accepted: 03/04/2009] [Indexed: 02/08/2023]
Abstract
Inhibition of acetyl-CoA carboxylase (ACC) may prevent lipid-induced insulin resistance and type 2 diabetes, making the enzyme an attractive pharmaceutical target. Although the enzyme is highly conserved amongst animals, only the yeast enzyme structure is available for rational drug design. The use of biophysical assays has permitted the identification of a specific C-terminal truncation of the 826-residue human ACC2 carboxyl transferase (CT) domain that is both functionally competent to bind inhibitors and crystallizes in their presence. This C-terminal truncation led to the determination of the human ACC2 CT domain-CP-640186 complex crystal structure, which revealed distinctions from the yeast-enzyme complex. The human ACC2 CT-domain C-terminus is comprised of three intertwined alpha-helices that extend outwards from the enzyme on the opposite side to the ligand-binding site. Differences in the observed inhibitor conformation between the yeast and human structures are caused by differing residues in the binding pocket.
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Affiliation(s)
- Kevin P. Madauss
- Department of Computational and Structural Chemistry, GlaxoSmithKline Inc., Five Moore Drive, Research Triangle Park, NC 27709, USA
| | - William A. Burkhart
- Department of Biochemical Reagents and Assay Development, GlaxoSmithKline Inc., Five Moore Drive, Research Triangle Park, NC 27709, USA
| | - Thomas G. Consler
- Department of Biochemical Reagents and Assay Development, GlaxoSmithKline Inc., Five Moore Drive, Research Triangle Park, NC 27709, USA
| | - David J. Cowan
- Department of Chemistry in the Center for Excellence in Metabolic Pathways Drug Discovery, GlaxoSmithKline Inc., Five Moore Drive, Research Triangle Park, NC 27709, USA
| | - William K. Gottschalk
- Institute for Genome Sciences and Policy and Department of Medicine, Division of Neurology, Duke University, Durham, NC 27708, USA
| | - Aaron B. Miller
- Department of Computational and Structural Chemistry, GlaxoSmithKline Inc., Five Moore Drive, Research Triangle Park, NC 27709, USA
| | - Steven A. Short
- Department of Biochemical Reagents and Assay Development, GlaxoSmithKline Inc., Five Moore Drive, Research Triangle Park, NC 27709, USA
| | - Thuy B. Tran
- Department of Physiology, UNC School of Medicine, University of North Carolina, Chapel Hill, NC 27515, USA
| | - Shawn P. Williams
- Department of Computational and Structural Chemistry, GlaxoSmithKline Inc., Five Moore Drive, Research Triangle Park, NC 27709, USA
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148
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Castle JC, Hara Y, Raymond CK, Garrett-Engele P, Ohwaki K, Kan Z, Kusunoki J, Johnson JM. ACC2 is expressed at high levels in human white adipose and has an isoform with a novel N-terminus [corrected]. PLoS One 2009; 4:e4369. [PMID: 19190759 PMCID: PMC2629817 DOI: 10.1371/journal.pone.0004369] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Accepted: 12/12/2008] [Indexed: 11/18/2022] Open
Abstract
Acetyl-CoA carboxylases ACC1 and ACC2 catalyze the carboxylation of acetyl-CoA to malonyl-CoA, regulating fatty-acid synthesis and oxidation, and are potential targets for treatment of metabolic syndrome. Expression of ACC1 in rodent lipogenic tissues and ACC2 in rodent oxidative tissues, coupled with the predicted localization of ACC2 to the mitochondrial membrane, have suggested separate functional roles for ACC1 in lipogenesis and ACC2 in fatty acid oxidation. We find, however, that human adipose tissue, unlike rodent adipose, expresses more ACC2 mRNA relative to the oxidative tissues muscle and heart. Human adipose, along with human liver, expresses more ACC2 than ACC1. Using RT-PCR, real-time PCR, and immunoprecipitation we report a novel isoform of ACC2 (ACC2.v2) that is expressed at significant levels in human adipose. The protein generated by this isoform has enzymatic activity, is endogenously expressed in adipose, and lacks the N-terminal sequence. Both ACC2 isoforms are capable of de novo lipogenesis, suggesting that ACC2, in addition to ACC1, may play a role in lipogenesis. The results demonstrate a significant difference in ACC expression between human and rodents, which may introduce difficulties for the use of rodent models for development of ACC inhibitors.
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Affiliation(s)
- John C. Castle
- Rosetta Inpharmatics LLC, Seattle, Washington, United States of America
- * E-mail: (JCC); (JMJ)
| | - Yoshikazu Hara
- Metabolic Disorder Research, Tsukuba Research Institute, Banyu Pharmaceutical Co., Ltd., Tsukuba, Ibaraki, Japan
| | | | | | - Kenji Ohwaki
- Metabolic Disorder Research, Tsukuba Research Institute, Banyu Pharmaceutical Co., Ltd., Tsukuba, Ibaraki, Japan
| | - Zhengyan Kan
- Rosetta Inpharmatics LLC, Seattle, Washington, United States of America
| | - Jun Kusunoki
- Metabolic Disorder Research, Tsukuba Research Institute, Banyu Pharmaceutical Co., Ltd., Tsukuba, Ibaraki, Japan
| | - Jason M. Johnson
- Rosetta Inpharmatics LLC, Seattle, Washington, United States of America
- * E-mail: (JCC); (JMJ)
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149
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Wolf G. Role of fatty acids in the development of insulin resistance and type 2 diabetes mellitus. Nutr Rev 2009; 66:597-600. [PMID: 18826455 DOI: 10.1111/j.1753-4887.2008.00110.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Insulin resistance is defined as the reduced responsiveness to normal circulating levels of insulin. It is the basic condition of type 2 diabetes mellitus, in which both experimental animals and humans accumulate lipids intracellularly in skeletal muscle and liver. Measurement of these lipids in humans, using nuclear magnetic resonance spectroscopy after lipid infusion, indicated they could cause inhibition of the glucose transporter GLUT4, thereby suppressing glucose entry into cells and inhibiting glucose oxidation and glycogen synthesis in muscle. Furthermore, it is known that the enzyme acetyl-CoA carboxylase2 (ACC2) suppresses the oxidation of fatty acids by inhibiting the entry of fatty acids into mitochondria. Further support for the lipocentric hypothesis of the pathogenesis of insulin resistance was provided by knocking out the gene coding for ACC2 in mice; this led to greater fatty acid oxidation, reduced fat mass and, in consequence, greatly enhanced insulin sensitivity. These studies suggest that a specific inhibitor of ACC2 would have therapeutic potential for type 2 diabetes mellitus.
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Affiliation(s)
- George Wolf
- Department of Nutritional Sciences and Toxicology at the University of California, Berkeley, California 94720, USA.
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150
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Guillou H, Martin PGP, Pineau T. Transcriptional regulation of hepatic fatty acid metabolism. Subcell Biochem 2008; 49:3-47. [PMID: 18751906 DOI: 10.1007/978-1-4020-8831-5_1] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The liver is a major site of fatty acid synthesis and degradation. Transcriptional regulation is one of several mechanisms controlling hepatic metabolism of fatty acids. Two transcription factors, namely SREBP1-c and PPARalpha, appear to be the main players controlling synthesis and degradation of fatty acids respectively. This chapter briefly presents fatty acid metabolism. The first part focuses on SREBP1-c contribution to the control of gene expression relevant to fatty acid synthesis and the main mechanisms of activation for this transcriptional program. The second part reviews the evidence for the involvement of PPARalpha in the control of fatty acid degradation and the key features of this nuclear receptor. Finally, the third part aims at summarizing recent advances in our current understanding of how these two transcription factors fit in the regulatory networks that sense hormones or nutrients, including cellular fatty acids, and govern the transcription of genes implicated in hepatic fatty acid metabolism.
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Affiliation(s)
- Hervé Guillou
- Laboratoire de Pharmacologie et Toxicologie UR66, INRA, F-3100 Toulouse, France
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