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Bai J, He Z, Li Y, Jiang X, Yu H, Tan Q. Mono-2-ethylhexyl phthalate induces the expression of genes involved in fatty acid synthesis in HepG2 cells. Environ Toxicol Pharmacol 2019; 69:104-111. [PMID: 31004931 DOI: 10.1016/j.etap.2019.04.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 03/28/2019] [Accepted: 04/08/2019] [Indexed: 06/09/2023]
Abstract
Mono-2-ethylhexyl phthalate (MEHP) is a major bioactive metabolite in the widely used industrial plasticizer diethylhexyl phthalate (DEHP) that has been found to be toxic to the liver. The aim of this study is to determine whether MEHP exposure can change the expression of fatty acid metabolism-related genes in HepG2 cells, which might be related to non-alcoholic fatty liver disease (NAFLD). The results revealed that exposure to MEHP promoted lipid accumulation in HepG2 cells. The levels of intracellular triglycerides in the hepatocytes increased after exposure to 0.8-100 μM MEHP for 24 h and 48 h. The genetic expressions of SREBP-1c, ChREBP, ACC1, FASN, and SCD significantly increased at 6 h after exposure to MEHP. At 24 h, the expression of the SREBP-1c and ChREBP genes remained increased, while the expression of the FASN and SCD genes decreased. At 48 h, the expression of SREBP-1c, ChREBP, ACC1, FASN, and SCD decreased. Furthermore, the levels of proteins including ACC1, FASN, SCD, and ChREBP (except SREBP-1c) increased at 24 h. These findings suggest that MEHP exposure can promote fatty acid synthesis in hepatocytes by regulating the expression of relevant genes and proteins, contributing to NAFLD.
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Affiliation(s)
- Jianying Bai
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China.
| | - Zhen He
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Yaofu Li
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Xuexia Jiang
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Hongmei Yu
- Department of Health Statistics, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
| | - Qing Tan
- Department of Environmental Health, School of Public Health, Shanxi Medical University, Taiyuan, 030001, China
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Endo Y, Onodera A, Obata-Ninomiya K, Koyama-Nasu R, Asou HK, Ito T, Yamamoto T, Kanno T, Nakajima T, Ishiwata K, Kanuka H, Tumes DJ, Nakayama T. ACC1 determines memory potential of individual CD4 + T cells by regulating de novo fatty acid biosynthesis. Nat Metab 2019; 1:261-275. [PMID: 32694782 DOI: 10.1038/s42255-018-0025-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 12/07/2018] [Indexed: 01/14/2023]
Abstract
Immunological memory is central to adaptive immunity and protection from disease. Changing metabolic demands as antigen-specific T cells transition from effector to memory cells have been well documented, but the cell-specific pathways and molecules that govern this transition are poorly defined. Here we show that genetic deletion of ACC1, a rate-limiting enzyme in fatty acid biosynthesis, enhances the formation of CD4+ T memory cells. ACC1-deficient effector helper T (Th) cells have similar metabolic signatures to wild-type memory Th cells, and expression of the gene encoding ACC1, Acaca, was inversely correlated with a memory gene signature in individual cells. Inhibition of ACC1 function enhances memory T cell formation during parasite infection in mice. Using single-cell analyses we identify a memory precursor-enriched population (CCR7hiCD137lo) present during early differentiation of effector CD4+ T cells. Our data indicate that fatty acid metabolism directs cell fate determination during the generation of memory CD4+ T cells.
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Affiliation(s)
- Yusuke Endo
- Department of Immunology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
- Laboratory of Medical Omics Research, KAZUSA DNA Research Institute, Kisarazu, Chiba, Japan
| | - Atsushi Onodera
- Department of Immunology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Kazushige Obata-Ninomiya
- Department of Advanced Allergology of the Airway, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Ryo Koyama-Nasu
- Department of Immunology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Hikari K Asou
- Department of Immunology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Toshihiro Ito
- Department of Immunology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Takeshi Yamamoto
- Department of Immunology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Toshio Kanno
- Department of Immunology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
- Laboratory of Medical Omics Research, KAZUSA DNA Research Institute, Kisarazu, Chiba, Japan
| | - Takahiro Nakajima
- Department of Immunology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
- Laboratory of Medical Omics Research, KAZUSA DNA Research Institute, Kisarazu, Chiba, Japan
| | - Kenji Ishiwata
- Department of Tropical Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Hirotaka Kanuka
- Department of Tropical Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Damon J Tumes
- Department of Immunology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Toshinori Nakayama
- Department of Immunology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan.
- AMED-CREST, AMED, Chuo-ku, Chiba, Japan.
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Brandon AE, Stuart E, Leslie SJ, Hoehn KL, James DE, Kraegen EW, Turner N, Cooney GJ. Minimal impact of age and housing temperature on the metabolic phenotype of Acc2-/- mice. J Endocrinol 2016; 228:127-34. [PMID: 26668208 PMCID: PMC4906541 DOI: 10.1530/joe-15-0444] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/14/2015] [Indexed: 12/13/2022]
Abstract
An important regulator of fatty acid oxidation (FAO) is the allosteric inhibition of CPT-1 by malonyl-CoA produced by the enzyme acetyl-CoA carboxylase 2 (ACC2). Initial studies suggested that deletion of Acc2 (Acacb) increased fat oxidation and reduced adipose tissue mass but in an independently generated strain of Acc2 knockout mice we observed increased whole-body and skeletal muscle FAO and a compensatory increase in muscle glycogen stores without changes in glucose tolerance, energy expenditure or fat mass in young mice (12-16 weeks). The aim of the present study was to determine whether there was any effect of age or housing at thermoneutrality (29 °C; which reduces total energy expenditure) on the phenotype of Acc2 knockout mice. At 42-54 weeks of age, male WT and Acc2(-/-) mice had similar body weight, fat mass, muscle triglyceride content and glucose tolerance. Consistent with younger Acc2(-/-) mice, aged Acc2(-/-) mice showed increased whole-body FAO (24 h average respiratory exchange ratio=0.95±0.02 and 0.92±0.02 for WT and Acc2(-/-) mice respectively, P<0.05) and skeletal muscle glycogen content (+60%, P<0.05) without any detectable change in whole-body energy expenditure. Hyperinsulinaemic-euglycaemic clamp studies revealed no difference in insulin action between groups with similar glucose infusion rates and tissue glucose uptake. Housing Acc2(-/-) mice at 29 °C did not alter body composition, glucose tolerance or the effects of fat feeding compared with WT mice. These results confirm that manipulation of Acc2 may alter FAO in mice, but this has little impact on body composition or insulin action.
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Affiliation(s)
- Amanda E Brandon
- Diabetes and Metabolism DivisionGarvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales 2010, AustraliaSt Vincent's Clinical SchoolUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Medical SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Biotechnology and Biomolecular SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Molecular Bioscience and Sydney Medical SchoolCharles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia Diabetes and Metabolism DivisionGarvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales 2010, AustraliaSt Vincent's Clinical SchoolUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Medical SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Biotechnology and Biomolecular SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Molecular Bioscience and Sydney Medical SchoolCharles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Ella Stuart
- Diabetes and Metabolism DivisionGarvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales 2010, AustraliaSt Vincent's Clinical SchoolUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Medical SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Biotechnology and Biomolecular SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Molecular Bioscience and Sydney Medical SchoolCharles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Simon J Leslie
- Diabetes and Metabolism DivisionGarvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales 2010, AustraliaSt Vincent's Clinical SchoolUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Medical SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Biotechnology and Biomolecular SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Molecular Bioscience and Sydney Medical SchoolCharles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Kyle L Hoehn
- Diabetes and Metabolism DivisionGarvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales 2010, AustraliaSt Vincent's Clinical SchoolUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Medical SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Biotechnology and Biomolecular SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Molecular Bioscience and Sydney Medical SchoolCharles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - David E James
- Diabetes and Metabolism DivisionGarvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales 2010, AustraliaSt Vincent's Clinical SchoolUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Medical SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Biotechnology and Biomolecular SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Molecular Bioscience and Sydney Medical SchoolCharles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Edward W Kraegen
- Diabetes and Metabolism DivisionGarvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales 2010, AustraliaSt Vincent's Clinical SchoolUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Medical SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Biotechnology and Biomolecular SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Molecular Bioscience and Sydney Medical SchoolCharles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia Diabetes and Metabolism DivisionGarvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales 2010, AustraliaSt Vincent's Clinical SchoolUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Medical SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Biotechnology and Biomolecular SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Molecular Bioscience and Sydney Medical SchoolCharles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Nigel Turner
- Diabetes and Metabolism DivisionGarvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales 2010, AustraliaSt Vincent's Clinical SchoolUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Medical SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Biotechnology and Biomolecular SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Molecular Bioscience and Sydney Medical SchoolCharles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Gregory J Cooney
- Diabetes and Metabolism DivisionGarvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales 2010, AustraliaSt Vincent's Clinical SchoolUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Medical SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Biotechnology and Biomolecular SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Molecular Bioscience and Sydney Medical SchoolCharles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia Diabetes and Metabolism DivisionGarvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales 2010, AustraliaSt Vincent's Clinical SchoolUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Medical SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Biotechnology and Biomolecular SciencesUniversity of New South Wales Australia, Sydney, New South Wales, AustraliaSchool of Molecular Bioscience and Sydney Medical SchoolCharles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
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Van Schaftingen E, Rzem R, Marbaix A, Collard F, Veiga-da-Cunha M, Linster CL. Metabolite proofreading, a neglected aspect of intermediary metabolism. J Inherit Metab Dis 2013; 36:427-34. [PMID: 23296366 DOI: 10.1007/s10545-012-9571-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 11/26/2012] [Accepted: 11/29/2012] [Indexed: 10/27/2022]
Abstract
Enzymes of intermediary metabolism are less specific than what is usually assumed: they often act on metabolites that are not their 'true' substrate, making abnormal metabolites that may be deleterious if they accumulate. Some of these abnormal metabolites are reconverted to normal metabolites by repair enzymes, which play therefore a role akin to the proofreading activities of DNA polymerases and aminoacyl-tRNA synthetases. An illustrative example of such repair enzymes is L-2-hydroxyglutarate dehydrogenase, which eliminates a metabolite abnormally made by a Krebs cycle enzyme. Mutations in L-2-hydroxyglutarate dehydrogenase lead to L-2-hydroxyglutaric aciduria, a leukoencephalopathy. Other examples are the epimerase and the ATP-dependent dehydratase that repair hydrated forms of NADH and NADPH; ethylmalonyl-CoA decarboxylase, which eliminates an abnormal metabolite formed by acetyl-CoA carboxylase, an enzyme of fatty acid synthesis; L-pipecolate oxidase, which repairs a metabolite formed by a side activity of an enzyme of L-proline biosynthesis. Metabolite proofreading enzymes are likely quite common, but most of them are still unidentified. A defect in these enzymes may account for new metabolic disorders.
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Scott KEN, Wheeler FB, Davis AL, Thomas MJ, Ntambi JM, Seals DF, Kridel SJ. Metabolic regulation of invadopodia and invasion by acetyl-CoA carboxylase 1 and de novo lipogenesis. PLoS One 2012; 7:e29761. [PMID: 22238651 PMCID: PMC3253107 DOI: 10.1371/journal.pone.0029761] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 12/04/2011] [Indexed: 01/04/2023] Open
Abstract
Invadopodia are membrane protrusions that facilitate matrix degradation and cellular invasion. Although lipids have been implicated in several aspects of invadopodia formation, the contributions of de novo fatty acid synthesis and lipogenesis have not been defined. Inhibition of acetyl-CoA carboxylase 1 (ACC1), the committed step of fatty acid synthesis, reduced invadopodia formation in Src-transformed 3T3 (3T3-Src) cells, and also decreased the ability to degrade gelatin. Inhibition of fatty acid synthesis through AMP-activated kinase (AMPK) activation and ACC phosphorylation also decreased invadopodia incidence. The addition of exogenous 16∶0 and 18∶1 fatty acid, products of de novo fatty acid synthesis, restored invadopodia and gelatin degradation to cells with decreased ACC1 activity. Pharmacological inhibition of ACC also altered the phospholipid profile of 3T3-Src cells, with the majority of changes occurring in the phosphatidylcholine (PC) species. Exogenous supplementation with the most abundant PC species, 34∶1 PC, restored invadopodia incidence, the ability to degrade gelatin and the ability to invade through matrigel to cells deficient in ACC1 activity. On the other hand, 30∶0 PC did not restore invadopodia and 36∶2 PC only restored invadopodia incidence and gelatin degradation, but not cellular invasion through matrigel. Pharmacological inhibition of ACC also reduced the ability of MDA-MB-231 breast, Snb19 glioblastoma, and PC-3 prostate cancer cells to invade through matrigel. Invasion of PC-3 cells through matrigel was also restored by 34∶1 PC supplementation. Collectively, the data elucidate the novel metabolic regulation of invadopodia and the invasive process by de novo fatty acid synthesis and lipogenesis.
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Affiliation(s)
- Kristen E. N. Scott
- Department of Cancer Biology, Wake Forest School of Medicine, Winston Salem, North Carolina, United States of America
| | - Frances B. Wheeler
- Department of Cancer Biology, Wake Forest School of Medicine, Winston Salem, North Carolina, United States of America
| | - Amanda L. Davis
- Department of Cancer Biology, Wake Forest School of Medicine, Winston Salem, North Carolina, United States of America
| | - Michael J. Thomas
- Department of Biochemistry, Wake Forest School of Medicine, Winston Salem, North Carolina, United States of America
- Comprehensive Cancer Center, Wake Forest School of Medicine, Winston Salem, North Carolina, United States of America
| | - James M. Ntambi
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Darren F. Seals
- Department of Cancer Biology, Wake Forest School of Medicine, Winston Salem, North Carolina, United States of America
- Comprehensive Cancer Center, Wake Forest School of Medicine, Winston Salem, North Carolina, United States of America
| | - Steven J. Kridel
- Department of Cancer Biology, Wake Forest School of Medicine, Winston Salem, North Carolina, United States of America
- Comprehensive Cancer Center, Wake Forest School of Medicine, Winston Salem, North Carolina, United States of America
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Pighon A, Gutkowska J, Jankowski M, Rabasa-Lhoret R, Lavoie JM. Exercise training in ovariectomized rats stimulates estrogenic-like effects on expression of genes involved in lipid accumulation and subclinical inflammation in liver. Metabolism 2011; 60:629-39. [PMID: 20674948 DOI: 10.1016/j.metabol.2010.06.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 05/12/2010] [Accepted: 06/14/2010] [Indexed: 02/06/2023]
Abstract
We hypothesized that the reduction in liver fat accumulation known to occur with exercise training in ovariectomized (Ovx) rats is associated with reduced expression of genes involved in lipogenesis while favoring the expression of transcription factors regulating lipid oxidation. We also tested the hypothesis that liver fat accumulation in Ovx rats is associated with an increased gene expression of several inflammatory biomarkers and that exercise training would attenuate this response. Sprague-Dawley female rats (14 weeks of age) were randomly divided into 4 groups of sedentary sham-operated (Sham), Ovx, Ovx with 17β-estradiol (E2) supplementation using a pellet (0.72 mg; 0.012 mg/d) with a biodegradable carrier binder, and Ovx trained with endurance exercise. Endurance exercise training consisted of continuous running on a motor-driven rodent treadmill 5 times per week for 5 weeks. Fat accumulation in liver as well as in adipose fat depots was higher (P < .01) in Ovx than in Sham rats. This response was prevented in Ovx animals with 17β-estradiol supplementation and with endurance exercise training. Liver gene expressions of sterol regulatory element-binding protein 1-c, stearoyl coenzyme A desaturase 1 (and its protein content), carbohydrate response element binding protein, and acetyl-coenzyme A carboxylase were increased with estrogen withdrawal (P < .01). These responses were corrected with E2 supplementation alone as well as with training alone. Conversely, hepatic peroxisome proliferator-activated receptor α messenger RNA levels were lower (P < .01) after estrogen removal compared with Sham rats. The lower hepatic peroxisome proliferator-activated receptor α messenger RNA levels in Ovx rats were reincreased by E2 replacement or by exercise training. Gene expression of proinflammatory cytokines including inhibitor-κB kinase β and interleukin-6, as well as protein content of nuclear factor-κB, was higher (P < .01) in Ovx than in Sham animals. E2 supplementation or exercise training prevented the expression of the proinflammatory markers. It is concluded that exercise training reduces fat accumulation in liver of Ovx rats possibly through regulation of key molecules involved in lipogenesis and lipid oxidation. Exercise training also acts as estrogens in properly regulating the expression of inflammatory biomarkers in liver of Ovx rats.
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Affiliation(s)
- Abdolnaser Pighon
- Department of Kinesiology, Université de Montréal, Montreal, Quebec, Canada.
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Tong C, Morrison A, Yan X, Zhao P, Yeung ED, Wang J, Xie J, Li J. Macrophage migration inhibitory factor deficiency augments cardiac dysfunction in Type 1 diabetic murine cardiomyocytes. J Diabetes 2010; 2:267-74. [PMID: 20923497 PMCID: PMC2991593 DOI: 10.1111/j.1753-0407.2010.00088.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND It has become evident that macrophage migration inhibitory factor (MIF) is associated with the development of Type 1 diabetes mellitus. The aim of the present study was to determine whether MIF plays a role in cardiac contractile dysfunction in T1DM mice. METHODS Mechanical and intracellular Ca(2+) properties were measured in cardiomyocytes isolated from wild-type (WT) and MIF-knockout (MIF-KO) mice administrated or not streptozotocin (200 mg/kg, i.p.). Relative stress signaling was evaluated using western blot analysis. RESULTS Peak shortening (PS) and maximal velocity of shortening/relengthening (±dL/dt) were reduced and the duration of relengthening (TR90) was prolonged in both WT and MIF-KO cardiomyocytes treated with STZ (P < 0.01 vs control), which may be associated with reduced intracellular Ca(2+) decay in both groups. However, STZ-treated WT cardiomyocytes demonstrated significantly better contractile function and intracellular Ca(2+) properties compared with STZ-treated MIF-KO cardiomyocytes (all P < 0.05). Interestingly, the physiological data clearly showed that blood glucose levels were significantly higher in STZ-treated MIF-KO mice than STZ-treated WT mice (P < 0.01). Moreover, phosphorylation of AMP-activated protein kinase (AMPK) and its direct downstream target acetyl-CoA carboxylase (ACC) was markedly lower in hearts from STZ-treated MIF-KO mice than STZ-treated WT mice (P < 0.05). There were no significant differences between untreated WT and MIF-KO control groups. CONCLUSIONS There is a beneficial action of MIF in the management of cardiac dysfunction in T1DM. The cardioprotective effect of MIF may be associated with AMPK signaling.
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Affiliation(s)
- Chao Tong
- Department of Pharmacology and Toxicology, SUNY University at Buffalo, Buffalo, NY 14214, USA
| | - Alex Morrison
- Department of Pharmacology and Toxicology, SUNY University at Buffalo, Buffalo, NY 14214, USA
| | - Xiaoyan Yan
- Department of Pharmacology and Toxicology, SUNY University at Buffalo, Buffalo, NY 14214, USA
| | - Peng Zhao
- Department of Cardiology, Shandong Provincial Hospital, Shandong University, Jinan, 250021
| | - Eddie D Yeung
- Department of Pharmacology and Toxicology, SUNY University at Buffalo, Buffalo, NY 14214, USA
| | - Jingying Wang
- Department of Pharmacology and Toxicology, SUNY University at Buffalo, Buffalo, NY 14214, USA
| | - Jianxin Xie
- School of Medicine, Shihezi University, Shihezi, P.R. China
| | - Ji Li
- Department of Pharmacology and Toxicology, SUNY University at Buffalo, Buffalo, NY 14214, USA
- School of Medicine, Shihezi University, Shihezi, P.R. China
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Stoppa GR, Cesquini M, Roman EA, Prada PO, Torsoni AS, Romanatto T, Saad MJ, Velloso LA, Torsoni MA. Intracerebroventricular injection of citrate inhibits hypothalamic AMPK and modulates feeding behavior and peripheral insulin signaling. J Endocrinol 2008; 198:157-68. [PMID: 18469022 DOI: 10.1677/joe-07-0428] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We hypothesized that citrate might modulate the AMP-activated protein kinase/acetyl-CoA carboxylase (AMPK)/(ACC) pathway and participate in neuronal feeding control and glucose homeostasis. To address this issue, we injected citrate into the lateral ventricle of rats. Intracerebroventricular (ICV) injection of citrate diminished the phosphorylation of hypothalamic AMPK/ACC, increased the expression of anorexigenic neuropeptide (pro-opiomelanocortin and corticotropin-releasing hormone), elevated the level of malonyl-CoA in the hypothalamus, and reduced food intake. No change was observed in the concentration of blood insulin after the injection of citrate. With a euglycemic-hyperinsulinemic clamp, the glucose infusion rate was higher in the citrate group than in the control group (28.6+/-0.8 vs 19.3+/-0.2 mU/kg body weight/min respectively), and so was glucose uptake in skeletal muscle and the epididymal fat pad. Concordantly, insulin receptor (IR), IR substrate type 1 (IRS1), IRS2, and protein kinase B (AKT) phosphorylation in adipose tissue and skeletal muscle was improved by citrate ICV treatment. Moreover, the treatment with citrate for 7 days promoted body weight loss and decreased the adipose tissue. Our results suggest that citrate and glucose may serve as signals of energy and nutrient availability to hypothalamic cells.
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Affiliation(s)
- Graziela R Stoppa
- Departamento de Bioquímica, IB, Universidade Estadual de Campinas, Campinas, SP, Brazil
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Kim KH, Shin HJ, Kim K, Choi HM, Rhee SH, Moon HB, Kim HH, Yang US, Yu DY, Cheong J. Hepatitis B virus X protein induces hepatic steatosis via transcriptional activation of SREBP1 and PPARgamma. Gastroenterology 2007; 132:1955-67. [PMID: 17484888 DOI: 10.1053/j.gastro.2007.03.039] [Citation(s) in RCA: 213] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2006] [Accepted: 02/15/2007] [Indexed: 12/23/2022]
Abstract
BACKGROUND & AIMS Hepatic steatosis occurs frequently in patients with chronic hepatitis B virus (HBV) or chronic hepatitis C virus (HCV) infection. Recently, several studies suggested that steatosis plays an important role as a cofactor in other liver diseases such as hepatic fibrosis, hepatitis, and liver cancer. In contrast to HCV, however, the molecular mechanism by which HBV mediates hepatic steatosis has not been clearly studied. Here, we show the molecular mechanism by which hepatitis B virus X protein (HBx) induces hepatic steatosis. METHODS Lipid accumulation and the expression of various lipid metabolic genes were investigated in HBx-transfected Chang liver cells, HepG2-HBx stable cells, and HBx-transgenic mice. RESULTS Overexpression of HBx induced hepatic lipid accumulation in HepG2-HBx stable cells and HBx-transgenic mice. It also up-regulated the messenger RNA and protein levels of sterol regulatory element binding protein 1, but not peroxisome proliferator-activated receptor alpha (PPARalpha). Moreover, we also determined that the expression of HBx increases PPARgamma gene expression as well as its transcriptional activity in hepatic cells, mediated by CCAAT enhancer binding protein alpha activation. Finally, we showed that HBx expression is able to up-regulate the gene expressions of various lipogenic and adipogenic enzymes in hepatic cells. CONCLUSIONS We showed that the increased HBx expression causes lipid accumulation in hepatic cells mediated by sterol regulatory element binding protein 1 and PPARgamma, which could be a putative molecular mechanism mediating the pathophysiology of HBV infection.
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Affiliation(s)
- Kook Hwan Kim
- Department of Molecular Biology, Pusan National University, Busan, Korea
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Pelletier A, Coderre L. Ketone bodies alter dinitrophenol-induced glucose uptake through AMPK inhibition and oxidative stress generation in adult cardiomyocytes. Am J Physiol Endocrinol Metab 2007; 292:E1325-32. [PMID: 17227964 DOI: 10.1152/ajpendo.00186.2006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
In aerobic conditions, the heart preferentially oxidizes fatty acids. However, during metabolic stress, glucose becomes the major energy source, and enhanced glucose uptake has a protective effect on heart function and cardiomyocyte survival. Thus abnormal regulation of glucose uptake may contribute to the development of cardiac disease in diabetics. Ketone bodies are often elevated in poorly controlled diabetics and are associated with increased cellular oxidative stress. Thus we sought to determine the effect of the ketone body beta-hydroxybutyrate (OHB) on cardiac glucose uptake during metabolic stress. We used 2,4-dinitrophenol (DNP), an uncoupler of the mitochondrial oxidative chain, to mimic hypoxia in cardiomyocytes. Our data demonstrated that chronic exposure to OHB provoked a concentration-dependent decrease of DNP action, resulting in 56% inhibition of DNP-mediated glucose uptake at 5 mM OHB. This was paralleled by a diminution of DNP-mediated AMP-activated protein kinase (AMPK) and p38 MAPK phosphorylation. Chronic exposure to OHB also increased reactive oxygen species (ROS) production by 1.9-fold compared with control cells. To further understand the role of ROS in OHB action, cardiomyocytes were incubated with H(2)O(2). Our results demonstrated that this treatment diminished DNP-induced glucose uptake without altering activation of the AMPK/p38 MAPK signaling pathway. Incubation with the antioxidant N-acetylcysteine partially restored DNP-mediated glucose but not AMPK/p38 MAPK activation. In conclusion, these results suggest that ketone bodies, through inhibition of the AMPK/p38 MAPK signaling pathway and ROS overproduction, regulate DNP action and thus cardiac glucose uptake. Altered glucose uptake in hyperketonemic states during metabolic stress may contribute to diabetic cardiomyopathy.
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Affiliation(s)
- Amélie Pelletier
- Montreal Diabetes Research Centre, Centre hospitalier de l'Université de Montréal, Montreal, Quebec, Canada
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11
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Jaswal JS, Gandhi M, Finegan BA, Dyck JRB, Clanachan AS. Effects of adenosine on myocardial glucose and palmitate metabolism after transient ischemia: role of 5'-AMP-activated protein kinase. Am J Physiol Heart Circ Physiol 2006; 291:H1883-92. [PMID: 16648181 DOI: 10.1152/ajpheart.01147.2005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Loss of cardioprotection by adenosine in hearts stressed by transient ischemia may be due to its effects on glucose metabolism. In the absence of transient ischemia, adenosine inhibits glycolysis, whereas it accelerates glycolysis after transient ischemia. Inasmuch as 5'-AMP-activated protein kinase (AMPK) is implicated as a regulator of glucose and fatty acid utilization, this study determined whether a differential alteration of AMPK activity contributes to acceleration of glycolysis by adenosine in hearts stressed by transient ischemia. Studies were performed in working rat hearts perfused aerobically under normal conditions or after transient ischemia (two 10-min periods of ischemia followed by 5 min of reperfusion). LV work was not affected by adenosine. AMPK phosphorylation was not affected by transient ischemia; however, phosphorylation and activity were increased nine- and threefold, respectively, by adenosine in stressed hearts. Phosphorylation of acetyl-CoA carboxylase and rates of palmitate oxidation were unaltered. Glycolysis and calculated proton production were increased 1.8- and 1.7-fold, respectively, in hearts with elevated AMPK activity. Elevated AMPK activity was associated with inhibition of glycogen synthesis and unchanged rates of glucose uptake and glycogenolysis. Phentolamine, an alpha-adrenoceptor antagonist, which prevents adenosine-induced activation of glycolysis in stressed hearts, prevented AMPK phosphorylation. These data demonstrate that adenosine-induced activation of AMPK after transient ischemia is not sufficient to alter palmitate oxidation or glucose uptake. Rather, activation of AMPK alters partitioning of glucose away from glycogen synthesis; the increase in glycolysis may in part contribute to loss of adenosine-induced cardioprotection in hearts subjected to transient ischemia.
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Affiliation(s)
- Jagdip S Jaswal
- Dept. of Pharmacology, Faculty of Medicine and Dentistry, Univ. of Alberta, Edmonton, AB, Canada
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12
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Kusunoki J, Kanatani A, Moller DE. Modulation of fatty acid metabolism as a potential approach to the treatment of obesity and the metabolic syndrome. Endocrine 2006; 29:91-100. [PMID: 16622296 DOI: 10.1385/endo:29:1:91] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2005] [Revised: 11/30/1999] [Accepted: 10/20/2005] [Indexed: 12/21/2022]
Abstract
Increased de novo lipogenesis and reduced fatty acid oxidation are probable contributors to adipose accretion in obesity. Moreover, these perturbations have a role in leading to non-alcoholic steatohepatitis, dyslipidemia, and insulin resistance--via "lipotoxicity"-related mechanisms. Research in this area has prompted an effort to evaluate several discrete enzymes in these pathways as targets for future therapeutic intervention. Acetyl-CoA carboxylase 1 (ACC1) and ACC2 regulate fatty acid synthesis and indirectly control fatty acid oxidation via a key product, malonyl CoA. Based on mouse genetic and preclinical pharmacologic evidence, inhibition of ACC1 and/or ACC2 may be a useful approach to treat obesity and metabolic syndrome. Similarly, available data suggest that inhibition of other enzymes in this pathway, including fatty acid synthase, stearoyl CoA desaturase, and diacylglycerol acytransferase 1, will have beneficial effects. AMP-activated protein kinase is a master regulator of nutrient metabolism, which controls several aspects of lipid metabolism. Activation of AMPK in selected tissues is also a potential therapeutic approach. Inhibition of hormone-sensitive lipase is another possible approach. The rationale for modulating the activity of these enzymes and their relative merits (and downsides) as possible therapeutic targets are further discussed.
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Affiliation(s)
- Jun Kusunoki
- Department of Metabolic Disorders, Banyu-Tsukuba Research Institute, Tsukuba, Japan
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13
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Yin L, Wang Y, Dridi S, Vinson C, Hillgartner FB. Role of CCAAT/enhancer-binding protein, histone acetylation, and coactivator recruitment in the regulation of malic enzyme transcription by thyroid hormone. Mol Cell Endocrinol 2005; 245:43-52. [PMID: 16293364 DOI: 10.1016/j.mce.2005.10.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Revised: 10/07/2005] [Accepted: 10/11/2005] [Indexed: 11/23/2022]
Abstract
In chick embryo hepatocytes, activation of malic enzyme gene transcription by triiodothyronine (T3) is mediated by a T3 response unit (T3RU) that contains five T3 response elements (T3REs) plus five accessory elements that enhance T3 responsiveness conferred by the T3REs. Results from in vitro binding assays indicate that one of the accessory elements (region F) binds CCAAT/enhancer-binding protein-alpha (C/EBPalpha). Here, we investigated the role of C/EBPalpha in the regulation of malic enzyme transcription by T3. Transfection analyses demonstrated that the stimulation of T3RE function by region F did not require the presence of additional malic enzyme gene promoter sequences. Expression of a dominant negative C/EBP inhibited the ability of region F to stimulate T3 responsiveness. In chromatin immunoprecipitation assays, C/EBPalpha and TR associated with the malic enzyme T3RU in the absence and presence of T3 with the extent of the association being greater in the presence of T3. These observations indicate that C/EBPalpha interacts with TR on the malic enzyme T3RU to enhance T3 regulation of malic enzyme gene transcription. T3 treatment increased the acetylation of histones, decreased the recruitment of nuclear receptor corepressor and increased the recruitment of steroid receptor coactivator-1, CREB binding protein, and the thyroid hormone associated protein/mediator complex at the malic enzyme T3RU. In contrast, T3 treatment had no effect on the acetylation of histones and the recruitment of corepressors and coactivators at the T3RU that mediates the T3 activation of acetyl-CoA carboxylase-alpha gene transcription. We propose that differences between the malic enzyme T3RU and the ACCalpha T3RU in the ability of T3 to modulate histone acetylation and coregulatory protein recruitment are due to differences in the composition of the nuclear receptor complexes that bind these regulatory regions.
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Affiliation(s)
- Liya Yin
- Department of Biochemistry and Molecular Pharmacology, School of Medicine, P.O. Box 9142, West Virginia University, Morgantown, 26506-9142, USA
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14
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Barber MC, Price NT, Travers MT. Structure and regulation of acetyl-CoA carboxylase genes of metazoa. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1733:1-28. [PMID: 15749055 DOI: 10.1016/j.bbalip.2004.12.001] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 11/02/2004] [Accepted: 12/01/2004] [Indexed: 11/16/2022]
Abstract
Acetyl-CoA carboxylase (ACC) plays a fundamental role in fatty acid metabolism. The reaction product, malonyl-CoA, is both an intermediate in the de novo synthesis of long-chain fatty acids and also a substrate for distinct fatty acyl-CoA elongation enzymes. In metazoans, which have evolved energy storage tissues to fuel locomotion and to survive periods of starvation, energy charge sensing at the level of the individual cell plays a role in fuel selection and metabolic orchestration between tissues. In mammals, and probably other metazoans, ACC forms a component of an energy sensor with malonyl-CoA, acting as a signal to reciprocally control the mitochondrial transport step of long-chain fatty acid oxidation through the inhibition of carnitine palmitoyltransferase I (CPT I). To reflect this pivotal role in cell function, ACC is subject to complex regulation. Higher metazoan evolution is associated with the duplication of an ancestral ACC gene, and with organismal complexity, there is an increasing diversity of transcripts from the ACC paraloges with the potential for the existence of several isozymes. This review focuses on the structure of ACC genes and the putative individual roles of their gene products in fatty acid metabolism, taking an evolutionary viewpoint provided by data in genome databases.
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Affiliation(s)
- Michael C Barber
- Hannah Research Institute, Ayr, KA6 5HL, Scotland, United Kingdom.
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Hoja U, Marthol S, Hofmann J, Stegner S, Schulz R, Meier S, Greiner E, Schweizer E. HFA1 encoding an organelle-specific acetyl-CoA carboxylase controls mitochondrial fatty acid synthesis in Saccharomyces cerevisiae. J Biol Chem 2004; 279:21779-86. [PMID: 14761959 DOI: 10.1074/jbc.m401071200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Saccharomyces cerevisiae gene, HFA1, encodes a >250-kDa protein, which is required for mitochondrial function. Hfa1p exhibits 72% overall sequence similarity (54% identity) to ACC1-encoded yeast cytoplasmic acetyl-CoA carboxylase. Nevertheless, HFA1 and ACC1 functions are not overlapping because mutants of the two genes have different phenotypes and do not complement each other. Whereas ACC1 is involved in cytoplasmic fatty acid synthesis, the phenotype of hfa1Delta disruptants resembles that of mitochondrial fatty-acid synthase mutants. They fail to grow on lactate or glycerol, and the mitochondrial cofactor, lipoic acid, is reduced to <10% of its normal cellular concentration. Other than Acc1p, the N-terminal sequence of Hfa1p comprises a canonical mitochondrial targeting signal together with a matrix protease cleavage site. Accordingly, the HFA1-encoded protein was specifically assigned by Western blotting of appropriate cell fractions to the mitochondrial compartment. Removal of the mitochondrial targeting sequence abolished the competence of HFA1 DNA to complement hfal null mutants. Conversely and in contrast to the intact HFA1 sequence, the signal sequence-free HFA1 gene complemented the mutational loss of cytoplasmic acetyl-CoA carboxylase. Expression of HFA1 under the control of the ACC1 promoter restored cellular ACC activity in ACC1-defective yeast mutants to wild type levels. From this finding, it is concluded that HFA1 encodes a specific mitochondrial acetyl-CoA carboxylase providing malonyl-CoA for intraorganellar fatty acid and, in particular, lipoic acid synthesis.
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Affiliation(s)
- Ursula Hoja
- Lehrstuhl für Biochemie der Universität Erlangen-Nürnberg, D-91058 Erlangen, Germany
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16
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Nagano Y, Sasaki Y. [Lipid metabolism in plants: fatty acid synthesis]. Tanpakushitsu Kakusan Koso 2003; 48:2113-20. [PMID: 14631789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
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17
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Rappleye CA, Tagawa A, Le Bot N, Ahringer J, Aroian RV. Involvement of fatty acid pathways and cortical interaction of the pronuclear complex in Caenorhabditis elegans embryonic polarity. BMC Dev Biol 2003; 3:8. [PMID: 14527340 PMCID: PMC270048 DOI: 10.1186/1471-213x-3-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2003] [Accepted: 10/03/2003] [Indexed: 11/21/2022]
Abstract
Background Cell polarity is essential for many decisions made during development. While investigation of polarity-specific factors has yielded great insights into the polarization process, little is known on how these polarity-specific factors link to the basic cellular mechanisms that function in non-polarity aspects of the cell. To better understand the mechanisms that establish embryonic polarity, we investigated genes required for polarity in the one-cell C. elegans embryo that are also required for other non-polarity functions. This has led to the identification of the Pod-class of mutants that are characterized by osmosensitive embryos and defects in anterior-posterior polarity. Results Mutation in either of two loci of this class, emb-8 and pod-2, disrupts embryonic polarization and results in osmotically-sensitive embryos. Loss of emb-8, a previously uncharacterized polarity gene, causes mislocalization of PAR-3 and PAR-2 that molecularly mark the anterior and posterior cortices. emb-8 encodes NADPH-cytochrome P450 reductase, a protein supplying electrons to cytochrome P450-family enzymes, some of which catalyze fatty acid modifications. Cloning of the previously characterized polarity gene pod-2 reveals it encodes acetyl-CoA carboxylase, an enzyme that catalyzes the first step in de novo fatty acid synthesis. Depletion of fatty acid synthase, the next enzyme in the biosynthetic pathway, by RNA-interference (RNAi) also causes similar loss of one-cell polarity. Furthermore, pod-2 polarity defects can be rescued by addition of exogenous fatty acids. By following the behavior of the pronucleus in emb-8 and pod-2 mutant embryos, we demonstrate that loss of polarity correlates with impaired interaction between the pronucleus-centrosome complex and the posterior cortex. Conclusions The characterization of emb-8 and pod-2 mutant embryos suggests that the pronucleus-centrosome complex interaction with the cortex plays a direct role in establishing polarity and that fatty acid pathways are important for this polarizing event.
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Affiliation(s)
- Chad A Rappleye
- present address: Dept. Molecular Microbiology, Washington University, St. Louis, MO 63110, U.S.A
| | - Akiko Tagawa
- present address: Inst. Biochemistry, ETH Hönggerberg, CH-8093 Zürich, Switzerland
| | - Nathalie Le Bot
- Wellcome Trust/CR UK Institute, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Julie Ahringer
- Wellcome Trust/CR UK Institute, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Raffi V Aroian
- Section of Cell and Developmental Biology, Univ. of California, San Diego, La Jolla, CA 92093, U.S.A
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18
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Abu-Elheiga L, Oh W, Kordari P, Wakil SJ. Acetyl-CoA carboxylase 2 mutant mice are protected against obesity and diabetes induced by high-fat/high-carbohydrate diets. Proc Natl Acad Sci U S A 2003; 100:10207-12. [PMID: 12920182 PMCID: PMC193540 DOI: 10.1073/pnas.1733877100] [Citation(s) in RCA: 290] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Malonyl-CoA, generated by acetyl-CoA carboxylases ACC1 and ACC2, is a key metabolite in the control of fatty acid synthesis and oxidation in response to dietary changes. ACC2 is associated to the mitochondria, and Acc2-/- mice have a normal lifespan and higher fatty acid oxidation rate and accumulate less fat. Mutant mice fed high-fat/high-carbohydrate diets weighed less than their WT cohorts, accumulated less fat, and maintained normal levels of insulin and glucose, whereas the WT mice became type-2 diabetic with hyperglycemic and hyperinsulinemic status. Fatty acid oxidation rates in the soleus muscle and in hepatocytes of Acc2-/- mice were significantly higher than those of WT cohorts and were not affected by the addition of insulin. mRNA levels of uncoupling proteins (UCPs) were significantly higher in adipose, heart (UCP2), and muscle (UCP3) tissues of mutant mice compared with those of the WT. The increase in the UCP levels along with increased fatty acid oxidation may play an essential role in the regulation of energy expenditure. Lowering intracellular fatty acid accumulation in the mutant relative to that of the WT mice may thus impact glucose transport by higher GLUT4 activity and insulin sensitivity. These results suggest that ACC2 plays an essential role in controlling fatty acid oxidation and is a potential target in therapy against obesity and related diseases.
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Affiliation(s)
- Lutfi Abu-Elheiga
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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19
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Abstract
Acetyl-CoA carboxylase (ACC) catalyses the first committed step of fatty acid synthesis, the carboxylation of acetyl-CoA to malonyl-CoA. Two physically distinct types of enzymes are found in nature. Bacterial and most plant chloroplasts contain a multi-subunit ACC (MS-ACC) enzyme that is readily dissociated into its component proteins. Mammals, fungi, and plant cytosols contain the second type of ACC, a single large multifunctional polypeptide. This review will focus on the structures, regulation, and enzymatic mechanisms of the bacterial and plant MS-ACCs.
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Affiliation(s)
- John E Cronan
- Department of Microbiology, B103 Chemical and Life Sciences Laboratory, University of Illinois, 601 S. Goodwin Avenue, Urbana, IL 61801, USA.
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20
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Abstract
Understanding how a regulatory protein occupies its sites in vivo is central to understanding gene regulation. Using the yeast Gal4 protein as a model for such studies, we have found 239 potential Gal4 binding sites in the yeast genome, 186 of which are in open reading frames (ORFs). This raises the questions of whether these sites are occupied by Gal4 and, if so, to what effect. We have analyzed the Saccharomyces cerevisiae ACC1 gene (encoding acetyl-coenzyme A carboxylase), which has three Gal4 binding sites in its ORF. The plasmid titration assay has demonstrated that Gal4 occupies these sites in the context of an active ACC1 gene. We also find that the expression of the ACC1 is reduced fourfold in galactose medium and that this reduction is dependent on the Gal4 binding sites, suggesting that Gal4 bound to the ORF sites affects transcription of ACC1. Interestingly, removal of the Gal4 binding sites has no obvious effect on the growth in galactose under laboratory conditions. In addition, though the sequence of the ACC1 gene is highly conserved among yeast species, these Gal4 binding sites are not present in the Kluyveromyces lactis ACC1 gene. We suggest that the occurrence of these sites may not be related to galactose regulation and a manifestation of the "noise" in the occurrence of Gal4 binding sites.
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Affiliation(s)
- Q Li
- Department of Internal Medicine and Biochemistry, University of Texas-Southwestern Medical Center, Dallas, Texas 75390-8573, USA
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21
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Tohnai N, Tanabe T. [Acetyl-CoA carboxylase(ACC)]. Nihon Rinsho 2001; 59 Suppl 2:214-8. [PMID: 11351577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Affiliation(s)
- N Tohnai
- National Cardiovascular Center Research Institute
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22
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Davis MS, Solbiati J, Cronan JE. Overproduction of acetyl-CoA carboxylase activity increases the rate of fatty acid biosynthesis in Escherichia coli. J Biol Chem 2000; 275:28593-8. [PMID: 10893421 DOI: 10.1074/jbc.m004756200] [Citation(s) in RCA: 348] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acetyl-CoA carboxylase (ACC) catalyzes the first committed step of the fatty acid synthetic pathway. Although ACC has often been proposed to be a major rate-controlling enzyme of this pathway, no direct tests of this proposal in vivo have been reported. We have tested this proposal in Escherichia coli. The genes encoding the four subunits of E. coli ACC were cloned in a single plasmid under the control of a bacteriophage T7 promoter. Upon induction of gene expression, the four ACC subunits were overproduced in equimolar amounts. Overproduction of the proteins resulted in greatly increased ACC activity with a concomitant increase in the intracellular level of malonyl-CoA. The effects of ACC overexpression on the rate of fatty acid synthesis were examined in the presence of a thioesterase, which provided a metabolic sink for fatty acid overproduction. Under these conditions ACC overproduction resulted in a 6-fold increase in the rate of fatty acid synthesis.
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Affiliation(s)
- M S Davis
- Departments of Microbiology and Biochemistry, University of Illinois, Urbana, Illinois 61801, USA
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23
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Vavvas D, Apazidis A, Saha AK, Gamble J, Patel A, Kemp BE, Witters LA, Ruderman NB. Contraction-induced changes in acetyl-CoA carboxylase and 5'-AMP-activated kinase in skeletal muscle. J Biol Chem 1997; 272:13255-61. [PMID: 9148944 DOI: 10.1074/jbc.272.20.13255] [Citation(s) in RCA: 318] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The concentration of malonyl-CoA, a negative regulator of fatty acid oxidation, diminishes acutely in contracting skeletal muscle. To determine how this occurs, the activity and properties of acetyl-CoA carboxylase beta (ACC-beta), the skeletal muscle isozyme that catalyzes malonyl-CoA formation, were examined in rat gastrocnemius-soleus muscles at rest and during contractions induced by electrical stimulation of the sciatic nerve. To avoid the problem of contamination of the muscle extract by mitochondrial carboxylases, an assay was developed in which ACC-beta was first purified by immunoprecipitation with a monoclonal antibody. ACC-beta was quantitatively recovered in the immunopellet and exhibited a high sensitivity to citrate (12-fold activation) and a Km for acetyl-CoA (120 microM) similar to that reported for ACC-beta purified by other means. After 5 min of contraction, ACC-beta activity was decreased by 90% despite an apparent increase in the cytosolic concentration of citrate, a positive regulator of ACC. SDS-polyacrylamide gel electrophoresis of both homogenates and immunopellets from these muscles showed a decrease in the electrophoretic mobility of ACC, suggesting that phosphorylation could account for the decrease in ACC activity. In keeping with this notion, citrate activation of ACC purified from contracting muscle was markedly depressed. In addition, homogenization of the muscles in a buffer free of phosphatase inhibitors and containing the phosphatase activators glutamate and MgCl2 or treatment of immunoprecipitated ACC-beta with purified protein phosphatase 2A abolished the decreases in both ACC-beta activity and electrophoretic mobility caused by contraction. The rapid decrease in ACC-beta activity after the onset of contractions (50% by 20 s) and its slow restoration to initial values during recovery (60-90 min) were paralleled temporally by reciprocal changes in the activity of the alpha2 but not the alpha1 isoform of 5'-AMP-activated protein kinase (AMPK). In conclusion, the results suggest that the decrease in ACC activity during muscle contraction is caused by an increase in its phosphorylation, most probably due, at least in part, to activation of the alpha2 isoform of AMPK. They also suggest a dual mechanism for ACC regulation in muscle in which inhibition by phosphorylation takes precedence over activation by citrate. These alterations in ACC and AMPK activity, by diminishing the concentration of malonyl-CoA, could be responsible for the increase in fatty acid oxidation observed in skeletal muscle during exercise.
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Affiliation(s)
- D Vavvas
- Department of Physiology and Diabetes and Metabolism Unit, Evans Department of Medicine, Boston University Medical Center, Boston, Massachusetts 02118, USA
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24
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Sasaki Y. [Plant acetyl-CoA carboxylases: strategy for survival]. Seikagaku 1996; 68:335-44. [PMID: 8727658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Y Sasaki
- School of Agricultural Sciences of Nagoya University
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25
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Corton JM, Hardie DG. Regulation of lipid biosynthesis by the AMP-activated protein kinase and its role in the hepatocellular response to stress. Prog Liver Dis 1996; 14:69-99. [PMID: 9055575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- J M Corton
- Department of Biochemistry, Medical Sciences Institute, University of Dundee, Scotland
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26
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Geelen MJ, Schoots WJ, Bijleveld C, Beynen AC. Dietary medium-chain fatty acids raise and (n-3) polyunsaturated fatty acids lower hepatic triacylglycerol synthesis in rats. J Nutr 1995; 125:2449-56. [PMID: 7562078 DOI: 10.1093/jn/125.10.2449] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The hypothesis tested was that dietary medium-chain or (n-3) polyunsaturated fatty acids, when compared with (n-6) polyunsaturated fatty acids, alter plasma triacylglycerol levels by affecting hepatic triacylglycerol synthesis as reflected by the activities of acetyl-CoA carboxylase, fatty acid synthase and diacylglycerol acyltransferase in liver. In two separate experiments rats were fed purified diets containing (n-6) polyunsaturated fatty acids in the form of corn oil and either (n-3) polyunsaturated fatty acids in the form of fish oil or medium-chain triacylglycerols (MCT). Consumption of MCT significantly raised plasma triacylglycerol concentrations, whereas fish oil feeding had a lowering effect compared with the corn oil-fed group. In individual rats, the hepatic triacylglycerol concentration was directly correlated with the plasma triacylglycerol concentration (r = 0.60, P < 0.001). The MCT oil diet vs. the corn oil diet markedly raised the activities of hepatic acetyl-CoA carboxylase, fatty acid synthase and diacylglycerol acyltransferase. In the rats fed fish oil, the activities of fatty acid synthase and diacylglycerol acyltransferase were significantly reduced, whereas the activity of acetyl-CoA carboxylase was not affected relative to activities in rats fed corn oil. The activities of the three enzymes were directly correlated with plasma triacylglycerol concentrations in individual rats (r = 0.60-0.75, P < 0.001). The type of fat in the diet probably affects the rate of hepatic triacylglycerol synthesis which is an important determinant of plasma triacylglycerol concentrations.
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Affiliation(s)
- M J Geelen
- Laboratory of Veterinary Biochemistry, Faculty of Veterinary Medicine, Utrecht University, The Netherlands
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27
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Shimomura I, Matsuzawa Y. [Metabolic steps related to fat accumulation]. Nihon Rinsho 1995; 53 Suppl:127-32. [PMID: 7563672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- I Shimomura
- Second Department of Internal Medicine, Osaka University Medical School
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28
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Shriver BJ, Roman-Shriver C, Allred JB. Depletion and repletion of biotinyl enzymes in liver of biotin-deficient rats: evidence of a biotin storage system. J Nutr 1993; 123:1140-9. [PMID: 8099368 DOI: 10.1093/jn/123.6.1140] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The quantities of biotinyl proteins in liver of young rats were compared with age-matched controls at intervals during depletion and repletion of biotin. Growth rate and the concentrations of biotinyl proteins previously proposed as mitochondrial storage forms of acetyl CoA carboxylase rapidly decreased in response to biotin deprivation, whereas neither the concentration nor activity of cytosolic acetyl CoA carboxylase was affected. Concentrations of carboxylases active within mitochondria (pyruvate carboxylase, propionyl CoA carboxylase and 3-methyl crotonyl CoA carboxylase) decreased only after d 28. When biotin was injected into biotin-deficient rats, concentrations of the carboxylases active within mitochondria were restored to control levels within 3 h, whereas the concentrations of putative mitochondrial storage forms of acetyl CoA carboxylase reached normal levels only after 9 h, indicating that the injected biotin was preferentially used for the synthesis of the carboxylases active within mitochondria rather than acetyl CoA carboxylase. Mitochondrial acetyl CoA carboxylase may serve as a reservoir to maintain a normal concentration of cytosolic acetyl CoA carboxylase in liver of rats deprived of biotin and provide biotin, indirectly, to maintain essentially normal concentrations of the biotinyl enzymes active within mitochondria for several weeks after rats were fed a biotin-deficient diet.
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Affiliation(s)
- B J Shriver
- Department of Food Science and Technology, Ohio State University, Columbus 43210
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Feingold KR, Soued M, Adi S, Staprans I, Shigenaga J, Doerrler W, Moser A, Grunfeld C. Tumor necrosis factor-increased hepatic very-low-density lipoprotein production and increased serum triglyceride levels in diabetic rats. Diabetes 1990; 39:1569-74. [PMID: 1978829 DOI: 10.2337/diab.39.12.1569] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Previous studies demonstrated that administration of tumor necrosis factor (TNF) to diabetic rats rapidly increases serum triglyceride levels and stimulates hepatic lipogenesis without affecting the activity of adipose tissue lipoprotein lipase or serum insulin levels. The purpose of this study was to determine the mechanism by which TNF increases serum triglyceride levels and stimulates hepatic fatty acid synthesis in diabetic animals. The maximal increase (approximately 2-fold) in serum triglyceride levels in diabetic rats is seen with a dose of 10 micrograms TNF/200 g body wt, and the half-maximal effect is observed with 5 micrograms TNF/200 g body wt. The clearance of labeled triglyceride-rich lipoproteins from the circulation is not affected by TNF administration (triglyceride t 1/2; diabetic vs. TNF-administered diabetic, 3.5 +/- 0.7 vs. 4.0 +/- 0.6 min, respectively; NS). The production of triglyceride, measured by the Triton WR-1339 technique, is increased twofold in diabetic animals after TNF administration. These results indicate that the rapid increase in serum triglyceride levels after TNF treatment is accounted for by increased hepatic lipoprotein secretion. TNF administration did not alter either the amount or activation state of hepatic acetyl-CoA carboxylase, a key regulatory enzyme in fatty acid synthesis. There was also no change in the hepatic levels of fatty acyl-CoA, an allosteric inhibitor of acetyl-CoA carboxylase. However, there was a 71% increase in hepatic citrate concentrations. Citrate is an allosteric activator of acetyl-CoA carboxylase, and changes in hepatic citrate concentrations have been shown to mediate changes in the rates of fatty acid synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- K R Feingold
- Department of Medicine, University of California, San Francisco
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Affiliation(s)
- D G Hardie
- Biochemistry Department, University, Dundee, Scotland, U.K
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Maniscalco WM, Finkelstein JN, Parkhurst AB. De novo fatty acid synthesis by freshly isolated alveolar type II epithelial cells. Biochim Biophys Acta 1983; 751:462-9. [PMID: 6133559 DOI: 10.1016/0005-2760(83)90307-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Fatty acid synthesis was studied in freshly isolated type II pneumocytes from rabbits by 3H2O and (U-14C)-labeled glucose, lactate and pyruvate incorporation and the activity of acetyl-CoA carboxylase. The rate of lactate incorporation into fatty acids was 3-fold greater than glucose incorporation; lactate incorporation into the glycerol portion of lipids was very low but glucose incorporation into this fraction was approximately equal to incorporation into fatty acids. The highest rate of de novo fatty acid synthesis (3H2O incorporation) required both glucose and lactate. Under these circumstances lactate provided 81.5% of the acetyl units while glucose provided 5.6%. Incubations with glucose plus pyruvate had a significantly lower rate of fatty acid synthesis than glucose plus lactate. The availability of exogenous palmitate decreased de novo fatty acid synthesis by 80% in the isolated cells. In a cell-free supernatant, acetyl-CoA carboxylase activity was almost completely inhibited by palmitoyl-CoA; citrate blunted this inhibition. These data indicate that the type II pneumocyte is capable of a high rate of de novo fatty acid synthesis and that lactate is a preferred source of acetyl units. The type II pneumocyte can rapidly decrease the rate of fatty acid synthesis, probably by allosteric inhibition of acetyl-CoA carboxylase, if exogenous fatty acids are available.
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Abstract
The effect of citrate on the different reactions catalyzed by rat mammary gland acetyl CoA carboxylase has been investigated. Citrate showed modest effect on the ATP-orthophosphate and ATP-ADP exchange reactions. In contrast, this tricarboxylic acid caused marked concentration-dependent stimulation of the acetyl CoA-malonyl CoA exchange reaction which was concomitant with the activation of acetyl CoA carboxylation. The data obtained are consistent with the suggestion that activation by citrate of the overall forward reaction (malonyl CoA synthesis) primarily reflects enhancement of the carboxyltransferase half-reaction catalyzed by rat mammary gland acetyl CoA carboxylase.
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