101
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Regulation and function of AMPK in physiology and diseases. Exp Mol Med 2016; 48:e245. [PMID: 27416781 PMCID: PMC4973318 DOI: 10.1038/emm.2016.81] [Citation(s) in RCA: 701] [Impact Index Per Article: 87.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 04/23/2016] [Accepted: 04/26/2016] [Indexed: 12/18/2022] Open
Abstract
5′-adenosine monophosphate (AMP)-activated protein kinase (AMPK) is an evolutionarily conserved serine/threonine kinase that was originally identified as the key player in maintaining cellular energy homeostasis. Intensive research over the last decade has identified diverse molecular mechanisms and physiological conditions that regulate the AMPK activity. AMPK regulates diverse metabolic and physiological processes and is dysregulated in major chronic diseases, such as obesity, inflammation, diabetes and cancer. On the basis of its critical roles in physiology and pathology, AMPK is emerging as one of the most promising targets for both the prevention and treatment of these diseases. In this review, we discuss the current understanding of the molecular and physiological regulation of AMPK and its metabolic and physiological functions. In addition, we discuss the mechanisms underlying the versatile roles of AMPK in diabetes and cancer.
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102
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Mottillo EP, Desjardins EM, Crane JD, Smith BK, Green AE, Ducommun S, Henriksen TI, Rebalka IA, Razi A, Sakamoto K, Scheele C, Kemp BE, Hawke TJ, Ortega J, Granneman JG, Steinberg GR. Lack of Adipocyte AMPK Exacerbates Insulin Resistance and Hepatic Steatosis through Brown and Beige Adipose Tissue Function. Cell Metab 2016; 24:118-29. [PMID: 27411013 PMCID: PMC5239668 DOI: 10.1016/j.cmet.2016.06.006] [Citation(s) in RCA: 247] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 04/20/2016] [Accepted: 06/10/2016] [Indexed: 12/22/2022]
Abstract
Brown (BAT) and white (WAT) adipose tissues play distinct roles in maintaining whole-body energy homeostasis, and their dysfunction can contribute to non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes. The AMP-activated protein kinase (AMPK) is a cellular energy sensor, but its role in regulating BAT and WAT metabolism is unclear. We generated an inducible model for deletion of the two AMPK β subunits in adipocytes (iβ1β2AKO) and found that iβ1β2AKO mice were cold intolerant and resistant to β-adrenergic activation of BAT and beiging of WAT. BAT from iβ1β2AKO mice had impairments in mitochondrial structure, function, and markers of mitophagy. In response to a high-fat diet, iβ1β2AKO mice more rapidly developed liver steatosis as well as glucose and insulin intolerance. Thus, AMPK in adipocytes is vital for maintaining mitochondrial integrity, responding to pharmacological agents and thermal stress, and protecting against nutrient-overload-induced NAFLD and insulin resistance.
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Affiliation(s)
- Emilio P Mottillo
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, 1280 Main St. W., Hamilton, Ontario L8N 3Z5, Canada
| | - Eric M Desjardins
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, 1280 Main St. W., Hamilton, Ontario L8N 3Z5, Canada
| | - Justin D Crane
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, 1280 Main St. W., Hamilton, Ontario L8N 3Z5, Canada
| | - Brennan K Smith
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, 1280 Main St. W., Hamilton, Ontario L8N 3Z5, Canada
| | - Alex E Green
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, 1280 Main St. W., Hamilton, Ontario L8N 3Z5, Canada
| | - Serge Ducommun
- Nestlé Institute of Health Sciences SA, EPFL Innovation Park, Lausanne, Switzerland
| | - Tora I Henriksen
- The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Irena A Rebalka
- Department of Pathology and Molecular Medicine, McMaster University, 1280 Main St. W., Hamilton, Ontario L8N 3Z5, Canada
| | - Aida Razi
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St. W., Hamilton, Ontario L8N 3Z5, Canada
| | - Kei Sakamoto
- Nestlé Institute of Health Sciences SA, EPFL Innovation Park, Lausanne, Switzerland
| | - Camilla Scheele
- The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Bruce E Kemp
- St Vincent's Institute and Department of Medicine, University of Melbourne, Fitzroy, Victoria 3065, Australia; Mary MacKillop Institute for Health Research Australian Catholic University, Victoria Parade, Fitzroy, Victoria 3065, Australia
| | - Thomas J Hawke
- Department of Pathology and Molecular Medicine, McMaster University, 1280 Main St. W., Hamilton, Ontario L8N 3Z5, Canada
| | - Joaquin Ortega
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St. W., Hamilton, Ontario L8N 3Z5, Canada
| | - James G Granneman
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit 48201, MI, USA
| | - Gregory R Steinberg
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, 1280 Main St. W., Hamilton, Ontario L8N 3Z5, Canada; Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St. W., Hamilton, Ontario L8N 3Z5, Canada.
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103
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Perilipin 5 restores the formation of lipid droplets in activated hepatic stellate cells and inhibits their activation. J Transl Med 2016; 96:791-806. [PMID: 27135793 DOI: 10.1038/labinvest.2016.53] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 02/10/2016] [Accepted: 03/07/2016] [Indexed: 12/15/2022] Open
Abstract
Hepatic stellate cells (HSC) are major effectors during hepatic fibrogenesis. The activation of HSC is coupled to the loss of lipid droplets (LDs), which are specialized organelles composed of neutral lipids surrounded by perilipins. LDs have emerged as a focal point of interest in understanding the metabolic regulation of intrahepatic lipids during lipid-mediated liver fibrogenesis. Perilipin 5 (Plin5) is a newly identified LD protein in the perilipin family, which plays a key role in regulating aspects of intracellular trafficking, signaling, and cytoskeletal organization in hepatocytes. Recent work in Plin5 knockout mice suggests a role in high fat diet-induced hepatic lipotoxicity. The current report is to evaluate the impact of Plin5 on HSC activation and to elucidate the underlying mechanisms. We now show that high fat diet-induced liver fibrosis is accompanied by an approximate 75% reduction in Plin5 in HSC, and that spontaneous activation of primary HSC produces temporally coincident loss of Plin5 expression and LD depletion. As modulating lipid content in HSC is a suggested strategy for inhibition of HSC activation and treatment of hepatic fibrosis, we asked whether exogenous Plin5 expression in primary HSC would reverse the activation phenotype and promote LD formation. Recombinant lentiviral Plin5 expression in primary mouse HSC restored the formation of LDs, increased lipid content by inducing expression of pro-lipogenic genes and suppressing expression of pro-lipolytic genes, and suppressed HSC activation (~two fold reduction in expression of procollagen and α-smooth muscle actin, two unique biomarkers for activated HSC). In addition, the expression of exogenous Plin5 in HSC attenuated cellular oxidative stress by reducing cellular reactive oxygen species, elevating cellular glutathione, and inducing gene expression of glutamate-cysteine ligase. Taken together, our results indicate that expression of Plin5 plays a critical role in the formation of LDs, the elevation of lipid content in HSC, and the inhibition of the activation of HSC.
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104
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Fipronil promotes adipogenesis via AMPKα-mediated pathway in 3T3-L1 adipocytes. Food Chem Toxicol 2016; 92:217-23. [PMID: 27103584 DOI: 10.1016/j.fct.2016.04.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 03/23/2016] [Accepted: 04/15/2016] [Indexed: 12/24/2022]
Abstract
Emerging evidence suggests that organochlorine, organophosphorus and neonicotinoid insecticide exposure may be linked to the development of obesity and type 2 diabetes. However, there is no knowledge of the potential influence of fipronil, which belongs to the phenylpyrazole chemical family, on obesity. Thus, the goal of this study was to determine the role of fipronil in adipogenesis using 3T3-L1 adipocytes. Fipronil treatment, at 10 μM, increased fat accumulation in 3T3-L1 adipocytes as well as promoted key regulators of adipocyte differentiation (CCAAT/enhancer-binding protein α and peroxisome proliferator-activated receptor gamma-γ), and key regulators of lipogenesis (acetyl-CoA carboxylase and fatty acid synthase). The activation of AMPKα with 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) abolished effects of fipronil on increased adipogenesis. These results suggest that fipronil alters adipogenesis and results in increased lipid accumulation through a AMPKα-mediated pathway.
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105
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Dubois V, Laurent MR, Jardi F, Antonio L, Lemaire K, Goyvaerts L, Deldicque L, Carmeliet G, Decallonne B, Vanderschueren D, Claessens F. Androgen Deficiency Exacerbates High-Fat Diet-Induced Metabolic Alterations in Male Mice. Endocrinology 2016; 157:648-65. [PMID: 26562264 DOI: 10.1210/en.2015-1713] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Androgen deficiency is associated with obesity, metabolic syndrome, and type 2 diabetes mellitus in men, but the mechanisms behind these associations remain unclear. In this study, we investigated the combined effects of androgen deficiency and high-fat diet (HFD) on body composition and glucose homeostasis in C57BL/6J male mice. Two models of androgen deficiency were used: orchidectomy (ORX) and androgen receptor knockout mice. Both models displayed higher adiposity and serum leptin levels upon HFD, whereas no differences were seen on a regular diet. Fat accumulation in HFD ORX animals was accompanied by increased sedentary behavior and occurred in spite of reduced food intake. HFD ORX mice showed white adipocyte hypertrophy, correlated with decreased mitochondrial content but not function as well as increased lipogenesis and decreased lipolysis suggested by the up-regulation of fatty acid synthase and the down-regulation of hormone-sensitive lipase. Both ORX and androgen receptor knockout exacerbated HFD-induced glucose intolerance by impairing insulin action in liver and skeletal muscle, as evidenced by the increased triglyceride and decreased glycogen content in these tissues. In addition, serum IL-1β levels were elevated, and pancreatic insulin secretion was impaired after ORX. Testosterone but not dihydrotestosterone supplementation restored the castration effects on body composition and glucose homeostasis. We conclude that sex steroid deficiency in combination with HFD exacerbates adiposity, insulin resistance, and β-cell failure in 2 preclinical male mouse models. Our findings stress the importance of a healthy diet in a clinical context of androgen deficiency and may have implications for the prevention of metabolic alterations in hypogonadal men.
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Affiliation(s)
- Vanessa Dubois
- Molecular Endocrinology Laboratory (V.D., M.R.L., L.A., F.C.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Gerontology and Geriatrics (M.R.L.), KU Leuven, 3000 Leuven, Belgium; Clinical and Experimental Endocrinology (F.J., L.A., G.C., B.D., D.V.), Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Gene Expression Unit (K.L., L.G.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Exercise Physiology Research Group (L.D.), Department of Kinesiology, KU Leuven, 3000 Leuven, Belgium; and Institute of Neuroscience (L.D.), Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Michaël R Laurent
- Molecular Endocrinology Laboratory (V.D., M.R.L., L.A., F.C.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Gerontology and Geriatrics (M.R.L.), KU Leuven, 3000 Leuven, Belgium; Clinical and Experimental Endocrinology (F.J., L.A., G.C., B.D., D.V.), Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Gene Expression Unit (K.L., L.G.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Exercise Physiology Research Group (L.D.), Department of Kinesiology, KU Leuven, 3000 Leuven, Belgium; and Institute of Neuroscience (L.D.), Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Ferran Jardi
- Molecular Endocrinology Laboratory (V.D., M.R.L., L.A., F.C.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Gerontology and Geriatrics (M.R.L.), KU Leuven, 3000 Leuven, Belgium; Clinical and Experimental Endocrinology (F.J., L.A., G.C., B.D., D.V.), Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Gene Expression Unit (K.L., L.G.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Exercise Physiology Research Group (L.D.), Department of Kinesiology, KU Leuven, 3000 Leuven, Belgium; and Institute of Neuroscience (L.D.), Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Leen Antonio
- Molecular Endocrinology Laboratory (V.D., M.R.L., L.A., F.C.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Gerontology and Geriatrics (M.R.L.), KU Leuven, 3000 Leuven, Belgium; Clinical and Experimental Endocrinology (F.J., L.A., G.C., B.D., D.V.), Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Gene Expression Unit (K.L., L.G.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Exercise Physiology Research Group (L.D.), Department of Kinesiology, KU Leuven, 3000 Leuven, Belgium; and Institute of Neuroscience (L.D.), Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Katleen Lemaire
- Molecular Endocrinology Laboratory (V.D., M.R.L., L.A., F.C.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Gerontology and Geriatrics (M.R.L.), KU Leuven, 3000 Leuven, Belgium; Clinical and Experimental Endocrinology (F.J., L.A., G.C., B.D., D.V.), Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Gene Expression Unit (K.L., L.G.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Exercise Physiology Research Group (L.D.), Department of Kinesiology, KU Leuven, 3000 Leuven, Belgium; and Institute of Neuroscience (L.D.), Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Lotte Goyvaerts
- Molecular Endocrinology Laboratory (V.D., M.R.L., L.A., F.C.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Gerontology and Geriatrics (M.R.L.), KU Leuven, 3000 Leuven, Belgium; Clinical and Experimental Endocrinology (F.J., L.A., G.C., B.D., D.V.), Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Gene Expression Unit (K.L., L.G.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Exercise Physiology Research Group (L.D.), Department of Kinesiology, KU Leuven, 3000 Leuven, Belgium; and Institute of Neuroscience (L.D.), Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Louise Deldicque
- Molecular Endocrinology Laboratory (V.D., M.R.L., L.A., F.C.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Gerontology and Geriatrics (M.R.L.), KU Leuven, 3000 Leuven, Belgium; Clinical and Experimental Endocrinology (F.J., L.A., G.C., B.D., D.V.), Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Gene Expression Unit (K.L., L.G.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Exercise Physiology Research Group (L.D.), Department of Kinesiology, KU Leuven, 3000 Leuven, Belgium; and Institute of Neuroscience (L.D.), Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Geert Carmeliet
- Molecular Endocrinology Laboratory (V.D., M.R.L., L.A., F.C.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Gerontology and Geriatrics (M.R.L.), KU Leuven, 3000 Leuven, Belgium; Clinical and Experimental Endocrinology (F.J., L.A., G.C., B.D., D.V.), Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Gene Expression Unit (K.L., L.G.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Exercise Physiology Research Group (L.D.), Department of Kinesiology, KU Leuven, 3000 Leuven, Belgium; and Institute of Neuroscience (L.D.), Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Brigitte Decallonne
- Molecular Endocrinology Laboratory (V.D., M.R.L., L.A., F.C.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Gerontology and Geriatrics (M.R.L.), KU Leuven, 3000 Leuven, Belgium; Clinical and Experimental Endocrinology (F.J., L.A., G.C., B.D., D.V.), Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Gene Expression Unit (K.L., L.G.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Exercise Physiology Research Group (L.D.), Department of Kinesiology, KU Leuven, 3000 Leuven, Belgium; and Institute of Neuroscience (L.D.), Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Dirk Vanderschueren
- Molecular Endocrinology Laboratory (V.D., M.R.L., L.A., F.C.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Gerontology and Geriatrics (M.R.L.), KU Leuven, 3000 Leuven, Belgium; Clinical and Experimental Endocrinology (F.J., L.A., G.C., B.D., D.V.), Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Gene Expression Unit (K.L., L.G.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Exercise Physiology Research Group (L.D.), Department of Kinesiology, KU Leuven, 3000 Leuven, Belgium; and Institute of Neuroscience (L.D.), Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Frank Claessens
- Molecular Endocrinology Laboratory (V.D., M.R.L., L.A., F.C.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Gerontology and Geriatrics (M.R.L.), KU Leuven, 3000 Leuven, Belgium; Clinical and Experimental Endocrinology (F.J., L.A., G.C., B.D., D.V.), Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Gene Expression Unit (K.L., L.G.), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Exercise Physiology Research Group (L.D.), Department of Kinesiology, KU Leuven, 3000 Leuven, Belgium; and Institute of Neuroscience (L.D.), Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
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106
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AMPK Regulation of Cell Growth, Apoptosis, Autophagy, and Bioenergetics. EXPERIENTIA SUPPLEMENTUM (2012) 2016; 107:45-71. [PMID: 27812976 DOI: 10.1007/978-3-319-43589-3_3] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In eukaryotic cells, AMP-activated protein kinase (AMPK) generally promotes catabolic pathways that produce ATP and at the same time inhibits anabolic pathways involved in different processes that consume ATP. As an energy sensor, AMPK is involved in the main cellular functions implicated in cell fate, such as cell growth and autophagy.Recently, AMPK has been connected with apoptosis regulation, although the molecular mechanism by which AMPK induces and/or inhibits cell death is not clear.This chapter reviews the essential role of AMPK in signaling pathways that respond to cellular stress and damage, highlighting the complex and reciprocal regulation between AMPK and their targets and effectors. The therapeutic implications of the role of AMPK in different pathologies such as diabetes, cancer, or mitochondrial dysfunctions are still controversial, and it is necessary to further investigate the molecular mechanisms underlying AMPK activation.
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107
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Burkewitz K, Weir HJM, Mair WB. AMPK as a Pro-longevity Target. EXPERIENTIA SUPPLEMENTUM (2012) 2016; 107:227-256. [PMID: 27812983 DOI: 10.1007/978-3-319-43589-3_10] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Chronic, age-associated diseases are already among the leading causes of morbidity and death in the world, a problem exacerbated by the rapidly rising proportion of elderly in the global population. This emergent epidemic represents the next great challenge for biomedical science and public health. Fortunately, decades of studies into the biology of aging have provided a head start by revealing an evolutionarily conserved network of genes that controls the rate and quality of the aging process itself and which can thereby be targeted for protection against age-onset disease. A number of dietary, genetic, and pharmacological interventions, including dietary restriction (DR) and the biguanide metformin, can extend healthy lifespan and reduce the incidence of multiple chronic conditions. Many of these interventions recurrently involve a core network of nutrient sensors: AMP-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), the insulin/insulin-like growth factor signaling pathway (IIS), and the sirtuins. Here, we will summarize how AMPK acts downstream of these pro-longevity interventions and within this network of nutrient sensors to control the cell and physiological processes important for defining how well we age.
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Affiliation(s)
- Kristopher Burkewitz
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA, 02115, USA.
| | - Heather J M Weir
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA, 02115, USA
| | - William B Mair
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA, 02115, USA.
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108
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Zhou X, Chen J, Chen J, Wu W, Wang X, Wang Y. The beneficial effects of betaine on dysfunctional adipose tissue and N6-methyladenosine mRNA methylation requires the AMP-activated protein kinase α1 subunit. J Nutr Biochem 2015; 26:1678-84. [DOI: 10.1016/j.jnutbio.2015.08.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 08/05/2015] [Accepted: 08/08/2015] [Indexed: 12/12/2022]
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109
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Kinnunen S, Mänttäri S, Herzig KH, Nieminen P, Mustonen AM, Saarela S. Effects of wintertime fasting and seasonal adaptation on AMPK and ACC in hypothalamus, adipose tissue and liver of the raccoon dog (Nyctereutes procyonoides). Comp Biochem Physiol A Mol Integr Physiol 2015; 192:44-51. [PMID: 26603554 DOI: 10.1016/j.cbpa.2015.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 11/11/2015] [Accepted: 11/16/2015] [Indexed: 12/25/2022]
Abstract
The raccoon dog (Nyctereutes procyonoides) is a canid with autumnal fattening and passive wintering strategy. We examined the effects of wintertime fasting and seasonality on AMP-activated protein kinase (AMPK), a regulator of metabolism, and its target, acetyl-CoA carboxylase (ACC) on the species. Twelve farmed raccoon dogs (eleven females/one male) were divided into two groups: half were fasted for ten weeks in December-March (winter fasted) and the others were fed ad libitum (winter fed). A third group (autumn fed, eight females) was fed ad libitum and sampled in December. Total AMPK, ACC and their phosphorylated forms (pAMPK, pACC) were measured from hypothalamus, liver, intra-abdominal (iWAT) and subcutaneous white adipose tissues (sWAT). The fasted animals lost 32% and the fed 20% of their body mass. Hypothalamic AMPK expression was lower and pACC levels higher in the winter groups compared to the autumn fed group. Liver pAMPK was lower in the winter fasted group, with consistently decreased ACC and pACC. AMPK and pAMPK were down-regulated in sWAT and iWAT of both winter groups, with a parallel decline in pACC in sWAT. The responses of AMPK and ACC to fasting were dissimilar to the effects observed previously in non-seasonal mammals and hibernators. Differences between the winter fed and autumn fed groups indicate that the functions of AMPK and ACC could be regulated in a season-dependent manner. Furthermore, the distinctive effects of prolonged fasting and seasonal adaptation on AMPK-ACC pathway could contribute to the wintering strategy of the raccoon dog.
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Affiliation(s)
- Sanni Kinnunen
- Department of Biology, University of Oulu, P.O. Box 3000, FI-90014, University of Oulu, Finland.
| | - Satu Mänttäri
- Finnish Institute of Occupational Health, Aapistie 1, FI-90220 Oulu, Finland
| | - Karl-Heinz Herzig
- Institute of Biomedicine, Biocenter Oulu, P.O. Box 5000, FI-90014, University of Oulu, Finland; Medical Research Center Oulu and Oulu University Hospital, Kajaanintie 50, FI-90220 Oulu, Finland
| | - Petteri Nieminen
- Institute of Biomedicine/Anatomy, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland; Department of Biology, Faculty of Science and Forestry, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
| | - Anne-Mari Mustonen
- Institute of Biomedicine/Anatomy, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland; Department of Biology, Faculty of Science and Forestry, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
| | - Seppo Saarela
- Department of Biology, University of Oulu, P.O. Box 3000, FI-90014, University of Oulu, Finland
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110
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Novikova DS, Garabadzhiu AV, Melino G, Barlev NA, Tribulovich VG. AMP-activated protein kinase: structure, function, and role in pathological processes. BIOCHEMISTRY (MOSCOW) 2015; 80:127-44. [PMID: 25756529 DOI: 10.1134/s0006297915020017] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Recently, AMP-activated protein kinase (AMPK) has emerged as a key regulator of energy balance at cellular and whole-body levels. Due to the involvement in multiple signaling pathways, AMPK efficiently controls ATP-consuming/ATP-generating processes to maintain energy homeostasis under stress conditions. Loss of the kinase activity or attenuation of its expression leads to a variety of metabolic disorders and increases cancer risk. In this review, we discuss recent findings on the structure of AMPK, its activation mechanisms, as well as the consequences of its targets in regulation of metabolism. Particular attention is given to low-molecular-weight compounds that activate or inhibit AMPK; the perspective of therapeutic use of such modulators in treatment of several common diseases is discussed.
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Affiliation(s)
- D S Novikova
- Saint Petersburg State Technological Institute (Technical University), St. Petersburg, 190013, Russia.
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111
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Lindahl M, Petrlova J, Dalla-Riva J, Wasserstrom S, Rippe C, Domingo-Espin J, Kotowska D, Krupinska E, Berggreen C, Jones HA, Swärd K, Lagerstedt JO, Göransson O, Stenkula KG. ApoA-I Milano stimulates lipolysis in adipose cells independently of cAMP/PKA activation. J Lipid Res 2015; 56:2248-59. [PMID: 26504176 DOI: 10.1194/jlr.m054767] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Indexed: 11/20/2022] Open
Abstract
ApoA-I, the main protein component of HDL, is suggested to be involved in metabolic homeostasis. We examined the effects of Milano, a naturally occurring ApoA-I variant, about which little mechanistic information is available. Remarkably, high-fat-fed mice treated with Milano displayed a rapid weight loss greater than ApoA-I WT treated mice, and a significantly reduced adipose tissue mass, without an inflammatory response. Further, lipolysis in adipose cells isolated from mice treated with either WT or Milano was increased. In primary rat adipose cells, Milano stimulated cholesterol efflux and increased glycerol release, independently of β-adrenergic stimulation and phosphorylation of hormone sensitive lipase (Ser563) and perilipin (Ser522). Stimulation with Milano had a significantly greater effect on glycerol release compared with WT but similar effect on cholesterol efflux. Pharmacological inhibition or siRNA silencing of ABCA1 did not diminish Milano-stimulated lipolysis, although binding to the cell surface was decreased, as analyzed by fluorescence microscopy. Interestingly, methyl-β-cyclodextrin, a well-described cholesterol acceptor, dose-dependently stimulated lipolysis. Together, these results suggest that decreased fat mass and increased lipolysis following Milano treatment in vivo is partly explained by a novel mechanism at the adipose cell level comprising stimulation of lipolysis independently of the canonical cAMP/protein kinase A signaling pathway.
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Affiliation(s)
- Maria Lindahl
- Medical Protein Science, Lund University, 221 84 Lund, Sweden Glucose Transport and Protein Trafficking, Lund University, 221 84 Lund, Sweden
| | - Jitka Petrlova
- Medical Protein Science, Lund University, 221 84 Lund, Sweden
| | | | | | - Catarina Rippe
- Cellular Biomechanics, Lund University, 221 84 Lund, Sweden
| | | | - Dorota Kotowska
- Glucose Transport and Protein Trafficking, Lund University, 221 84 Lund, Sweden
| | - Ewa Krupinska
- Medical Protein Science, Lund University, 221 84 Lund, Sweden
| | | | - Helena A Jones
- Molecular Endocrinology, Department of Experimental Medical Science, Biomedical Center, Lund University, 221 84 Lund, Sweden
| | - Karl Swärd
- Cellular Biomechanics, Lund University, 221 84 Lund, Sweden
| | | | - Olga Göransson
- Protein Phosphorylation, Lund University, 221 84 Lund, Sweden
| | - Karin G Stenkula
- Glucose Transport and Protein Trafficking, Lund University, 221 84 Lund, Sweden
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112
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Mazibuko SE, Joubert E, Johnson R, Louw J, Opoku AR, Muller CJF. Aspalathin improves glucose and lipid metabolism in 3T3-L1 adipocytes exposed to palmitate. Mol Nutr Food Res 2015; 59:2199-208. [PMID: 26310822 DOI: 10.1002/mnfr.201500258] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 07/21/2015] [Accepted: 07/29/2015] [Indexed: 01/14/2023]
Abstract
SCOPE Saturated-free fatty acids, such as palmitate, are associated with insulin resistance. This study aimed to establish if an aspalathin-enriched green rooibos extract (GRE) and, its major flavanoid, aspalathin (ASP) could contribute significantly to the amelioration of experimentally induced insulin resistance in 3T3-L1 adipocytes. METHODS AND RESULTS 3T3-L1 adipocytes were cultured in DMEM containing 0.75 mM palmitate for 16 h to induce insulin resistance before treatment for 3 h with GRE (10 μg/mL) or ASP (10 μM). GRE and ASP reversed the palmitate-induced insulin resistance. At a protein level GRE and ASP suppressed nuclear factor kappa beta (NF-κB), insulin receptor substrate one (serine 307) (IRS1 (Ser (307) )) and AMP-activated protein kinase phosphorylation and increased serine/threonine kinase AKT (AKT) activation, while only GRE increased glucose transporter four (Glut4) protein expression. Peroxisome proliferator-activated receptor alpha and gamma (PPARα and γ), and carnitine palmitoyltransferase one (CPT1) expression were increased by ASP alone. CONCLUSION Together these effects offer a plausible explanation for the ameliorative effect of GRE and ASP on insulin-resistance, an underlying cause for obesity and type 2 diabetes.
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Affiliation(s)
- Sithandiwe E Mazibuko
- Diabetes Discovery Platform, South African Medical Research Council, Tygerberg, South Africa.,Department of Biochemistry and Microbiology, University of Zululand, Kwa-Dlangezwa, South Africa
| | - Elizabeth Joubert
- Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Stellenbosch, South Africa.,Department of Food Science, Stellenbosch University, Matieland, South Africa
| | - Rabia Johnson
- Diabetes Discovery Platform, South African Medical Research Council, Tygerberg, South Africa
| | - Johan Louw
- Diabetes Discovery Platform, South African Medical Research Council, Tygerberg, South Africa
| | - Andrew R Opoku
- Department of Biochemistry and Microbiology, University of Zululand, Kwa-Dlangezwa, South Africa
| | - Christo J F Muller
- Diabetes Discovery Platform, South African Medical Research Council, Tygerberg, South Africa
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113
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Xu Y, Gu Y, Liu G, Zhang F, Li J, Liu F, Zhang Z, Ye J, Li Q. Cidec promotes the differentiation of human adipocytes by degradation of AMPKα through ubiquitin-proteasome pathway. Biochim Biophys Acta Gen Subj 2015; 1850:2552-62. [PMID: 26367078 DOI: 10.1016/j.bbagen.2015.09.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 08/30/2015] [Accepted: 09/10/2015] [Indexed: 12/15/2022]
Abstract
BACKGROUND We previously showed that Cidec was localized on the surface of lipid droplets and could promote the differentiation of human adipocytes, but the molecular mechanism was still unknown. METHODS & RESULTS In this study, we first sought to identify proteins that interact with Cidec using yeast two-hybrid system. The results revealed that Cidec could directly interact with AMPKα1 subunit. We further showed that AMPKα levels decreased while Cidec increased during the adipogenic differentiation of human adipocytes. Meanwhile, we observed that the increased Cidec could reduce AMPKα level in adipocytes, and the downregulation of AMPKα could help to promote the differentiation of adipocytes. The results of co-immunoprecipitation and immunofluorescent proved that Cidec biochemically interacted and co-localized with AMPKα1, which meant Cidec was a regulator for AMPKα stability through an ubiquitin-proteasome pathway. CONCLUSION Our data suggested that Cidec could interact with and down-regulate AMPKα through an ubiquitin-proteasome degradation pathway, which provided a possible mechanism of Cidec in promoting human adipocytes differentiation. GENERAL SIGNIFICANCE Our work proposed a new possible mechanism for human adipogenesis, and also provided a potential role of AMPKα as a target in treating obesity or obesity-related diseases.
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Affiliation(s)
- Yuqiao Xu
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China
| | - Yu Gu
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China
| | - Gang Liu
- Department of Plastic and Burns, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China
| | - Feng Zhang
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China
| | - Jie Li
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China
| | - Fang Liu
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China
| | - Zhiwen Zhang
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China
| | - Jing Ye
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China.
| | - Qing Li
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, Fourth Military Medical University, No.169 Changle West Road, Xi'an 710032, PR China.
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114
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Xing T, Xu X, Jiang N, Deng S. Effect of transportation and pre‐slaughter water shower spray with resting on AMP‐activated protein kinase, glycolysis and meat quality of broilers during summer. Anim Sci J 2015; 87:299-307. [DOI: 10.1111/asj.12426] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/02/2015] [Accepted: 02/20/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Tong Xing
- National Center of Meat Quality and Safety Control, Synergetic Innovation Center of Food Safety and NutritionNanjing Agricultural University Nanjing China
| | - Xinglian Xu
- National Center of Meat Quality and Safety Control, Synergetic Innovation Center of Food Safety and NutritionNanjing Agricultural University Nanjing China
| | - Nannan Jiang
- National Center of Meat Quality and Safety Control, Synergetic Innovation Center of Food Safety and NutritionNanjing Agricultural University Nanjing China
| | - ShaoLin Deng
- National Center of Meat Quality and Safety Control, Synergetic Innovation Center of Food Safety and NutritionNanjing Agricultural University Nanjing China
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115
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Zhang H, Guan M, Townsend KL, Huang TL, An D, Yan X, Xue R, Schulz TJ, Winnay J, Mori M, Hirshman MF, Kristiansen K, Tsang JS, White AP, Cypess AM, Goodyear LJ, Tseng YH. MicroRNA-455 regulates brown adipogenesis via a novel HIF1an-AMPK-PGC1α signaling network. EMBO Rep 2015; 16:1378-93. [PMID: 26303948 DOI: 10.15252/embr.201540837] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 07/24/2015] [Indexed: 01/06/2023] Open
Abstract
Brown adipose tissue (BAT) dissipates chemical energy as heat and can counteract obesity. MicroRNAs are emerging as key regulators in development and disease. Combining microRNA and mRNA microarray profiling followed by bioinformatic analyses, we identified miR-455 as a new regulator of brown adipogenesis. miR-455 exhibits a BAT-specific expression pattern and is induced by cold and the browning inducer BMP7. In vitro gain- and loss-of-function studies show that miR-455 regulates brown adipocyte differentiation and thermogenesis. Adipose-specific miR-455 transgenic mice display marked browning of subcutaneous white fat upon cold exposure. miR-455 activates AMPKα1 by targeting HIF1an, and AMPK promotes the brown adipogenic program and mitochondrial biogenesis. Concomitantly, miR-455 also targets the adipogenic suppressors Runx1t1 and Necdin, initiating adipogenic differentiation. Taken together, the data reveal a novel microRNA-regulated signaling network that controls brown adipogenesis and may be a potential therapeutic target for human metabolic disorders.
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Affiliation(s)
- Hongbin Zhang
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Meiping Guan
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA Department of Endocrinology and Metabolism, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Kristy L Townsend
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Tian Lian Huang
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Ding An
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Xu Yan
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Ruidan Xue
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Tim J Schulz
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA Adipocyte Development Research Group, German Institute of Human Nutrition, Potsdam, Germany
| | - Jonathon Winnay
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Marcelo Mori
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA Department of Biophysics, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Michael F Hirshman
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | | | - John S Tsang
- Systems Genomics and Bioinformatics Unit, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases (NIAID) and Trans-NIH Center for Human Immunology, National Institutes of Health, Bethesda, MD, USA
| | - Andrew P White
- Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Aaron M Cypess
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Laurie J Goodyear
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Yu-Hua Tseng
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA
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116
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Role of adenosine 5'-monophosphate-activated protein kinase in α-linolenic acid-induced intestinal lipid metabolism. Br J Nutr 2015; 114:866-72. [PMID: 26268732 DOI: 10.1017/s0007114515002391] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
n-3 Long-chain PUFA up-regulate intestinal lipid metabolism. However, whether these metabolic effects of PUFA on intestine are mediated by AMP-activated protein kinase (AMPK) remains to be elucidated. To determine the effects of α-linolenic acid (ALA) on intestinal fatty acid (FA) metabolism and whether these effects were affected by AMPK deletion, mice deficient in the catalytic subunit of AMPKα1 or AMPKα2 and wild-type (WT) mice were fed either a high-fat diet (HF) or HF supplemented with ALA (HF-A). The results showed that ALA supplementation decreased serum TAG content in WT mice. ALA also increased mRNA expression of genes (carnitine palmitoyltransferase 1a, acyl-CoA oxidase 1, medium-chain acyl-CoA dehydrogenase, cytochrome P450 4A10 and pyruvate dehydrogenase kinase isoenzyme 4a) involved in intestinal lipid oxidation and mRNA expression of TAG synthesis-related genes (monoacylglycerol O-acyltransferase 2, diacylglycerol O-acyltransferases 1 and 2) in WT mice. Consistent with these, expression levels of phosphorylated AMPKα1 and AMPKα2 were also increased in WT mice after ALA addition. However, in the absence of either AMPKα1 or AMPKα2, ALA supplementation failed to increase intestinal lipid oxidation. In addition, no significant effects of either diet (HF and HF-A) or genotype (WT, AMPKα1(-/-) and AMPKα2(-/-)) on FA uptake in the intestine and faecal TAG output were observed. Our results suggest that AMPK is indispensable for the effects of ALA on intestinal lipid oxidation.
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117
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Ko HJ, Lo CY, Wang BJ, Chiou RYY, Lin SM. Theaflavin-3,3′-digallate, a black tea polyphenol, stimulates lipolysis associated with the induction of mitochondrial uncoupling proteins and AMPK–FoxO3A–MnSOD pathway in 3T3-L1 adipocytes. J Funct Foods 2015. [DOI: 10.1016/j.jff.2015.05.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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118
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Rider MH. Role of AMP-activated protein kinase in metabolic depression in animals. J Comp Physiol B 2015; 186:1-16. [PMID: 26174210 DOI: 10.1007/s00360-015-0920-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/23/2015] [Accepted: 07/01/2015] [Indexed: 01/24/2023]
Abstract
AMP-activated protein kinase (AMPK) is a highly conserved eukaryotic protein serine/threonine kinase that controls cellular and whole body energy homoeostasis. AMPK is activated during energy stress by a rise in AMP:ATP ratio and maintains energy balance by phosphorylating targets to switch on catabolic ATP-generating pathways, while at the same time switching off anabolic ATP-consuming processes. Metabolic depression is a strategy used by many animals to survive environmental stress and has been extensively studied across phylogeny by comparative biochemists and physiologists, but the role of AMPK has only recently been addressed. This review first deals with the evolution of AMPK in eukaryotes (excluding plants and fungi) and its regulation. Changes in adenine nucleotides and AMPK activation are described in animals during environmental energy stress, before considering the involvement of AMPK in controlling β-oxidation, fatty acid synthesis, triacylglycerol mobilization and protein synthesis. Lastly, strategies are presented to validate the role of AMPK in mediating metabolic depression by phosphorylating downstream targets.
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Affiliation(s)
- Mark H Rider
- de Duve Institute and Université Catholique de Louvain, Avenue Hippocrate 75, 1200, Brussels, Belgium.
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119
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Parray HA, Yun JW. Proteomic Identification of Target Proteins of Thiodigalactoside in White Adipose Tissue from Diet-Induced Obese Rats. Int J Mol Sci 2015; 16:14441-63. [PMID: 26121299 PMCID: PMC4519851 DOI: 10.3390/ijms160714441] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 06/15/2015] [Accepted: 06/18/2015] [Indexed: 12/11/2022] Open
Abstract
Previously, galectin-1 (GAL1) was found to be up-regulated in obesity-prone subjects, suggesting that use of a GAL1 inhibitor could be a novel therapeutic approach for treatment of obesity. We evaluated thiodigalactoside (TDG) as a potent inhibitor of GAL1 and identified target proteins of TDG by performing comparative proteome analysis of white adipose tissue (WAT) from control and TDG-treated rats fed a high fat diet (HFD) using two dimensional gel electrophoresis (2-DE) combined with MALDI-TOF-MS. Thirty-two spots from a total of 356 matched spots showed differential expression between control and TDG-treated rats, as identified by peptide mass fingerprinting. These proteins were categorized into groups such as carbohydrate metabolism, tricarboxylic acid (TCA) cycle, signal transduction, cytoskeletal, and mitochondrial proteins based on functional analysis using Protein Annotation Through Evolutionary Relationship (PANTHER) and Database for Annotation, Visualization, Integrated Discovery (DAVID) classification. One of the most striking findings of this study was significant changes in Carbonic anhydrase 3 (CA3), Voltage-dependent anion channel 1 (VDAC1), phosphatidylethanolamine-binding protein 1 (PEBP1), annexin A2 (ANXA2) and lactate dehydrogenase A chain (LDHA) protein levels between WAT from control and TDG-treated groups. In addition, we confirmed increased expression of thermogenic proteins as well as reduced expression of lipogenic proteins in response to TDG treatment. These results suggest that TDG may effectively prevent obesity, and TDG-responsive proteins can be used as novel target proteins for obesity treatment.
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Affiliation(s)
- Hilal Ahmad Parray
- Department of Biotechnology, Daegu University, Kyungsan, Kyungbuk 712-714, Korea.
| | - Jong Won Yun
- Department of Biotechnology, Daegu University, Kyungsan, Kyungbuk 712-714, Korea.
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120
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Boone-Villa D, Aguilera-Méndez A, Miranda-Cervantes A, Fernandez-Mejia C. Effects of Biotin Supplementation in the Diet on Adipose Tissue cGMP Concentrations, AMPK Activation, Lipolysis, and Serum-Free Fatty Acid Levels. J Med Food 2015; 18:1150-6. [PMID: 25835526 DOI: 10.1089/jmf.2014.0170] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Several studies have shown that pharmacological concentrations of biotin decrease hyperlipidemia. The molecular mechanisms by which pharmacological concentrations of biotin modify lipid metabolism are largely unknown. Adipose tissue plays a central role in lipid homeostasis. In the present study, we analyzed the effects of biotin supplementation in adipose tissue on signaling pathways and critical proteins that regulate lipid metabolism, as well as on lipolysis. In addition, we assessed serum fatty acid concentrations. Male BALB/cAnN Hsd mice were fed a control or a biotin-supplemented diet (control: 1.76 mg biotin/kg; supplemented: 97.7 mg biotin/kg diet) over 8 weeks postweaning. Compared with the control group, biotin-supplemented mice showed an increase in the levels of adipose guanosine 3',5'-cyclic monophosphate (cGMP) (control: 30.3±3.27 pmol/g wet tissue; supplemented: 49.5±3.44 pmol/g wet tissue) and of phosphorylated forms of adenosine 5'-monophosphate-activated protein kinase (AMPK; 65.2%±1.06%), acetyl-coenzyme A (CoA), carboxylase-1 (196%±68%), and acetyl-CoA carboxylase-2 (78.1%±18%). Serum fatty acid concentrations were decreased (control: 1.12±0.04 mM; supplemented: 0.91±0.03 mM), and no change in lipolysis was found (control: 0.29±0.05 μmol/mL; supplemented: 0.33±0.08 μmol/mL). In conclusion, 8 weeks of dietary biotin supplementation increased adipose tissue cGMP content and protein expression of the active form of AMPK and of the inactive forms of acetyl-CoA carboxylase-1 and acetyl-CoA carboxylase-2. Serum fatty acid levels fell, and no change in lipolysis was observed. These findings provide insight into the effects of biotin supplementation on adipose tissue and support its use in the treatment of dyslipidemia.
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Affiliation(s)
- Daniel Boone-Villa
- Unidad de Genética de la Nutrición, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México , Instituto Nacional de Pediatría, Mexico City, Mexico
| | - Asdrubal Aguilera-Méndez
- Unidad de Genética de la Nutrición, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México , Instituto Nacional de Pediatría, Mexico City, Mexico
| | - Adriana Miranda-Cervantes
- Unidad de Genética de la Nutrición, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México , Instituto Nacional de Pediatría, Mexico City, Mexico
| | - Cristina Fernandez-Mejia
- Unidad de Genética de la Nutrición, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México , Instituto Nacional de Pediatría, Mexico City, Mexico
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121
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Traditional Herbal Formula Oyaksungi-San Inhibits Adipogenesis in 3T3-L1 Adipocytes. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 2015:949461. [PMID: 25802547 PMCID: PMC4353446 DOI: 10.1155/2015/949461] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 09/30/2014] [Accepted: 10/07/2014] [Indexed: 01/05/2023]
Abstract
Background. Oyaksungi-san (OYSGS) is a herbal formula that has been used for treating cardiovascular diseases in traditional Asian medicine. Here, we investigated the antiadipogenic effect of OYSGS extract in 3T3-L1 adipose cells. Methods. 3T3-L1 preadipocytes were differentiated into adipocytes with or without OYSGS. After differentiation, we measured Oil Red O staining, glycerol-3-phosphate dehydrogenase (GPDH) activity, leptin production, mRNA, and protein levels of adipogenesis-related factors. Results. OYSGS extract dramatically inhibited intracellular lipid accumulation in the differentiated adipocytes. It also significantly suppressed the (GPDH) activity, triglyceride (TG) content, and leptin production by reducing the expression of adipogenesis-related genes including lipoprotein lipase, fatty acid binding protein 4, CCAAT/enhancer-binding protein-alpha (C/EBP-α), and peroxisome proliferator-activated receptor gamma (PPAR-γ). Furthermore, OYSGS clearly enhanced phosphorylation of AMP-activated protein kinase (AMPK) as well as its substrate acetyl CoA (ACC) carboxylase. Conclusions. Our results demonstrate that OYSGS negatively controls TG accumulation in 3T3-L1 adipocytes. We suggest antiadipogenic activity of OYSGS and its potential benefit in preventing obesity.
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122
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Wu Y, Song P, Zhang W, Liu J, Dai X, Liu Z, Lu Q, Ouyang C, Xie Z, Zhao Z, Zhuo X, Viollet B, Foretz M, Wu J, Yuan Z, Zou MH. Activation of AMPKα2 in adipocytes is essential for nicotine-induced insulin resistance in vivo. Nat Med 2015; 21:373-82. [PMID: 25799226 PMCID: PMC4390501 DOI: 10.1038/nm.3826] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 02/17/2015] [Indexed: 12/15/2022]
Abstract
Cigarette smoking promotes body weight reduction in humans while paradoxically also promoting insulin resistance (IR) and hyperinsulinemia. However, the mechanisms behind these effects are unclear. Here we show that nicotine, a major constituent of cigarette smoke, selectively activates AMP-activated protein kinase α2 (AMPKα2) in adipocytes, which in turn phosphorylates MAP kinase phosphatase-1 (MKP1) at serine 334, initiating its proteasome-dependent degradation. The nicotine-dependent reduction of MKP1 induces the aberrant activation of both p38 mitogen-activated protein kinase and c-Jun N-terminal kinase, leading to increased phosphorylation of insulin receptor substrate 1 (IRS1) at serine 307. Phosphorylation of IRS1 leads to its degradation, protein kinase B inhibition, and the loss of insulin-mediated inhibition of lipolysis. Consequently, nicotine increases lipolysis, which results in body weight reduction, but this increase also elevates the levels of circulating free fatty acids and thus causes IR in insulin-sensitive tissues. These results establish AMPKα2 as an essential mediator of nicotine-induced whole-body IR in spite of reductions in adiposity.
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Affiliation(s)
- Yue Wu
- 1] Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA. [2] Department of Cardiology, Cardiovascular Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Ping Song
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Wencheng Zhang
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Junhui Liu
- Department of Cardiology, Cardiovascular Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Xiaoyan Dai
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Zhaoyu Liu
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Qiulun Lu
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Changhan Ouyang
- 1] Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA. [2] Key Laboratory of Hubei Province on Cardio-Cerebral Diseases, Hubei University of Science and Technology, Xianning, Hubei, China
| | - Zhonglin Xie
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Zhengxing Zhao
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Xiaozhen Zhuo
- Department of Cardiology, Cardiovascular Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Benoit Viollet
- 1] INSERM, U1016, Institut Cochin, Paris, France. [2] CNRS, UMR 8104, Paris, France. [3] Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Marc Foretz
- 1] INSERM, U1016, Institut Cochin, Paris, France. [2] CNRS, UMR 8104, Paris, France. [3] Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Jiliang Wu
- Key Laboratory of Hubei Province on Cardio-Cerebral Diseases, Hubei University of Science and Technology, Xianning, Hubei, China
| | - Zuyi Yuan
- Department of Cardiology, Cardiovascular Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Ming-Hui Zou
- 1] Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA. [2] Key Laboratory of Hubei Province on Cardio-Cerebral Diseases, Hubei University of Science and Technology, Xianning, Hubei, China
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Resveratrol induces brown-like adipocyte formation in white fat through activation of AMP-activated protein kinase (AMPK) α1. Int J Obes (Lond) 2015; 39:967-76. [PMID: 25761413 PMCID: PMC4575949 DOI: 10.1038/ijo.2015.23] [Citation(s) in RCA: 223] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 11/25/2014] [Accepted: 12/02/2014] [Indexed: 12/12/2022]
Abstract
Objective Development of brown-like/beige adipocytes in white adipose tissue (WAT) helps to reduce obesity. Thus, we investigated the effects of resveratrol, a dietary polyphenol capable of preventing obesity and related complications in humans and animal models, on brown-like adipocyte formation in inguinal WAT (iWAT). Methods CD1 female mice (5-month-old) were fed a high-fat diet with/without 0.1% resveratrol. In addition, primary stromal vascular cells separated from iWAT were subjected to resveratrol treatment. Markers of brown-like (beige) adipogenesis were measured and the involvement of AMP-activated protein kinase (AMPK) α1 was assessed using conditional knockout. Results Resveratrol significantly increased mRNA and/or protein expression of brown adipocyte markers including uncoupling protein 1 (UCP1), PR domain-containing 16 (PRDM16), Cell death-inducing DFFA-like effector A (Cidea), elongation of very long chain fatty acids protein 3 (Elovl3), peroxisome proliferator-activated receptor-γ coactivator 1α (PGC1α), cytochrome C and pyruvate dehydrogenase (PDH) in differentiated iWAT stromal vascular cells (SVC), suggesting that resveratrol induced brown-like adipocyte formation in vitro. Concomitantly, resveratrol markedly enhanced AMPKα1 phosphorylation and differentiated SVC oxygen consumption. Such changes were absent in cells lacking AMPKα1, showing that AMPKα1 is a critical mediator of resveratrol action. Resveratrol also induced beige adipogenesis in vivo along with the appearance of multiocular adipocytes, increased UCP1 expression and enhanced fatty acid oxidation. Conclusion Resveratrol induces brown-like adipocyte formation in iWAT via AMPKα1 activation and suggest that its beneficial anti-obesity effects may be partly due to the browning of WAT and as a consequence, increased oxygen consumption.
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Zhou X, Wu W, Chen J, Wang X, Wang Y. AMP-activated protein kinase is required for the anti-adipogenic effects of alpha-linolenic acid. Nutr Metab (Lond) 2015; 12:10. [PMID: 25774202 PMCID: PMC4358912 DOI: 10.1186/s12986-015-0006-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Accepted: 02/13/2015] [Indexed: 11/25/2022] Open
Abstract
Background n-3 long chain polyunsaturated fatty acid (n-3 LC PUFA) increases β-oxidation and limits lipid accumulation in adipocytes. The current study was conducted to determine whether their precursor alpha-linolenic acid (ALA) could also exert the above effects and how AMP-activated protein kinase (AMPK) was involved. Methods AMPKα1−/−, AMPKα2−/− mice and wild-type (WT) mice were fed a high-fat diet (HFD) or HFD with ALA. Body weight was recorded weekly and serum was collected. Adipocytes size and expression of key players involved in mitochondrial biogenesis and lipid oxidation were also measured. Results Our results showed an elevated serum adiponectin level and a decreased leptin and insulin level in WT mice fed HFD with ALA when compared with WT mice fed HFD. In addition, dietary ALA decreased epididymal adiposity and adipocytes size in WT mice. At protein level, mitochondrial genes (peroxisome proliferator-activated receptor gamma coactivator 1 alpha [PGC1α] and nuclear respiratory factor-1 [nrf1]) and β-oxidation related genes (carnitine palmitoyltransferase 1A [CPT1a] and peroxisome proliferator-activated receptor alpha [PPARα]) were upregulated by dietary ALA in epididymal fat of WT mice. Consistently, dietary ALA also increased mitochondrial genomic DNA copy numbers. Moreover, lipogenesis was repressed by dietary ALA, indicated by that expression of fatty acid synthase (FAS), acetyl CoA carboxylase (ACC) and stearoyl-CoA desaturase 1 (SCD1) were decreased. However, these aforementioned effects were abolished in the AMPKα1 and AMPKα2 knockout mice. Conclusions Our results suggest that ALA could improve adipose tissue function and its anti-adipogenic effects are dependent on AMPK.
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Affiliation(s)
- Xihong Zhou
- Key Laboratory of Animal Nutrition and Feed Science, Ministry of Agriculture, Zhejiang Provincial Laboratory of Feed and Animal Nutrition, Institute of Feed Science, Zhejiang University, Hangzhou, Zhejiang 310058 PR China
| | - Weiche Wu
- Key Laboratory of Animal Nutrition and Feed Science, Ministry of Agriculture, Zhejiang Provincial Laboratory of Feed and Animal Nutrition, Institute of Feed Science, Zhejiang University, Hangzhou, Zhejiang 310058 PR China
| | - Jingqing Chen
- Key Laboratory of Animal Nutrition and Feed Science, Ministry of Agriculture, Zhejiang Provincial Laboratory of Feed and Animal Nutrition, Institute of Feed Science, Zhejiang University, Hangzhou, Zhejiang 310058 PR China
| | - Xinxia Wang
- Key Laboratory of Animal Nutrition and Feed Science, Ministry of Agriculture, Zhejiang Provincial Laboratory of Feed and Animal Nutrition, Institute of Feed Science, Zhejiang University, Hangzhou, Zhejiang 310058 PR China
| | - Yizhen Wang
- Key Laboratory of Animal Nutrition and Feed Science, Ministry of Agriculture, Zhejiang Provincial Laboratory of Feed and Animal Nutrition, Institute of Feed Science, Zhejiang University, Hangzhou, Zhejiang 310058 PR China
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Shao Y, Yuan G, Zhang J, Guo X. Liraglutide reduces lipogenetic signals in visceral adipose of db/db mice with AMPK activation and Akt suppression. DRUG DESIGN DEVELOPMENT AND THERAPY 2015; 9:1177-84. [PMID: 25733821 PMCID: PMC4342181 DOI: 10.2147/dddt.s79175] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Liraglutide, a glucagon-like peptide-1 analog, has been proved to reduce body weight and visceral adipose tissue (VAT) in human studies. In this study, we aimed at examining lipogenetic signal changes in VAT after weight-loss with liraglutide in db/db mice. The mice were divided into two groups: liraglutide-treated group (n=14, 8-week-old, fasting glucose. >10 mmol/L, liraglutide 300 μg/kg twice a day for 4 weeks) and control group (n=14, saline). We found body weight gain and food intake were reduced after liraglutide treatment (P<0.05). Compared to the control group, the VAT weights were significantly lower in the treated group (2.32±0.37 g versus 3.20±0.30 g, P<0.01) than that in control group. In VAT, compared with control group, the lipogenetic transcription factors PPARγ and C/EBPα expressions were both reduced with pAMPK and pACC increased 3.5-fold and 2.31-fold respectively, while pAkt and pP38MAPK were reduced 0.38-fold and 0.62-fold respectively (P<0.01). In conclusion, VAT was reduced after weight loss with AMPK activation and Akt suppression with liraglutide treatment, which was associated with reduction of lipogenetic process in VAT.
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Affiliation(s)
- Yimin Shao
- Department of Endocrinology, Peking University First Hospital, Beijing, People's Republic of China
| | - Geheng Yuan
- Department of Endocrinology, Peking University First Hospital, Beijing, People's Republic of China
| | - Junqing Zhang
- Department of Endocrinology, Peking University First Hospital, Beijing, People's Republic of China
| | - Xiaohui Guo
- Department of Endocrinology, Peking University First Hospital, Beijing, People's Republic of China
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Fatty acid signaling: the new function of intracellular lipases. Int J Mol Sci 2015; 16:3831-55. [PMID: 25674855 PMCID: PMC4346929 DOI: 10.3390/ijms16023831] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 11/19/2014] [Accepted: 01/21/2015] [Indexed: 12/21/2022] Open
Abstract
Until recently, intracellular triacylglycerols (TAG) stored in the form of cytoplasmic lipid droplets have been considered to be only passive “energy conserves”. Nevertheless, degradation of TAG gives rise to a pleiotropic spectrum of bioactive intermediates, which may function as potent co-factors of transcription factors or enzymes and contribute to the regulation of numerous cellular processes. From this point of view, the process of lipolysis not only provides energy-rich equivalents but also acquires a new regulatory function. In this review, we will concentrate on the role that fatty acids liberated from intracellular TAG stores play as signaling molecules. The first part provides an overview of the transcription factors, which are regulated by fatty acids derived from intracellular stores. The second part is devoted to the role of fatty acid signaling in different organs/tissues. The specific contribution of free fatty acids released by particular lipases, hormone-sensitive lipase, adipose triacylglycerol lipase and lysosomal lipase will also be discussed.
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Du L, Yang YH, Wang YM, Xue CH, Kurihara H, Takahashi K. EPA-enriched phospholipids ameliorate cancer-associated cachexia mainly via inhibiting lipolysis. Food Funct 2015; 6:3652-62. [DOI: 10.1039/c5fo00478k] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
EPA-PL rescues the cancer-associated cachexia via inhibiting lipolysis.
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Affiliation(s)
- Lei Du
- Faculty of Fisheries Sciences
- Hokkaido University
- Hakodate
- Japan
- College of Food Science and Engineering
| | - Yu-Hong Yang
- Faculty of Fisheries Sciences
- Hokkaido University
- Hakodate
- Japan
- College of Food Science and Engineering
| | - Yu-Ming Wang
- College of Food Science and Engineering
- Ocean University of China
- Qingdao
- People's Republic of China
| | - Chang-Hu Xue
- College of Food Science and Engineering
- Ocean University of China
- Qingdao
- People's Republic of China
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Wang Y, Yan C, Liu L, Wang W, Du H, Fan W, Lutfy K, Jiang M, Friedman TC, Liu Y. 11β-Hydroxysteroid dehydrogenase type 1 shRNA ameliorates glucocorticoid-induced insulin resistance and lipolysis in mouse abdominal adipose tissue. Am J Physiol Endocrinol Metab 2015; 308:E84-95. [PMID: 25389364 PMCID: PMC4281684 DOI: 10.1152/ajpendo.00205.2014] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Long-term glucocorticoid exposure increases the risk for developing type 2 diabetes. Prereceptor activation of glucocorticoid availability in target tissue by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) coupled with hexose-6-phosphate dehydrogenase (H6PDH) is an important mediator of the metabolic syndrome. We explored whether the tissue-specific modulation of 11β-HSD1 and H6PDH in adipose tissue mediates glucocorticoid-induced insulin resistance and lipolysis and analyzed the effects of 11β-HSD1 inhibition on the key lipid metabolism genes and insulin-signaling cascade. We observed that corticosterone (CORT) treatment increased expression of 11β-HSD1 and H6PDH and induced lipase HSL and ATGL with suppression of p-Thr(172) AMPK in adipose tissue of C57BL/6J mice. In contrast, CORT induced adipose insulin resistance, as reflected by a marked decrease in IR and IRS-1 gene expression with a reduction in p-Thr(308) Akt/PKB. Furthermore, 11β-HSD1 shRNA attenuated CORT-induced 11β-HSD1 and lipase expression and improved insulin sensitivity with a concomitant stimulation of pThr(308) Akt/PKB and p-Thr(172) AMPK within adipose tissue. Addition of CORT to 3T3-L1 adipocytes enhanced 11β-HSD1 and H6PDH and impaired p-Thr(308) Akt/PKB, leading to lipolysis. Knockdown of 11β-HSD1 by shRNA attenuated CORT-induced lipolysis and reversed CORT-mediated inhibition of pThr(172) AMPK, which was accompanied by a parallel improvement of insulin signaling response in these cells. These findings suggest that elevated adipose 11β-HSD1 expression may contribute to glucocorticoid-induced insulin resistance and adipolysis.
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Affiliation(s)
- Ying Wang
- Division of Endocrinology, Metabolism, and Molecular Medicine, Charles R. Drew University of Medicine and Sciences, University of California Los Angeles (UCLA) School of Medicine, Los Angeles, California
| | - Chaoying Yan
- Department of Pediatrics, First Hospital, Jilin University, ChangChun, China
| | - Limei Liu
- Department of Endocrinology and Metabolism, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai Diabetes Institute, Shanghai, China
| | - Wei Wang
- Division of Endocrinology, Metabolism, and Molecular Medicine, Charles R. Drew University of Medicine and Sciences, University of California Los Angeles (UCLA) School of Medicine, Los Angeles, California
| | - Hanze Du
- Division of Endocrinology, Metabolism, and Molecular Medicine, Charles R. Drew University of Medicine and Sciences, University of California Los Angeles (UCLA) School of Medicine, Los Angeles, California
| | - Winnie Fan
- Division of Endocrinology, Metabolism, and Molecular Medicine, Charles R. Drew University of Medicine and Sciences, University of California Los Angeles (UCLA) School of Medicine, Los Angeles, California
| | - Kabirullah Lutfy
- Division of Endocrinology, Metabolism, and Molecular Medicine, Charles R. Drew University of Medicine and Sciences, University of California Los Angeles (UCLA) School of Medicine, Los Angeles, California; Department of Pharmaceutical Sciences, Western University of Health Sciences, Pomona, California; and
| | - Meisheng Jiang
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Theodore C Friedman
- Division of Endocrinology, Metabolism, and Molecular Medicine, Charles R. Drew University of Medicine and Sciences, University of California Los Angeles (UCLA) School of Medicine, Los Angeles, California
| | - Yanjun Liu
- Division of Endocrinology, Metabolism, and Molecular Medicine, Charles R. Drew University of Medicine and Sciences, University of California Los Angeles (UCLA) School of Medicine, Los Angeles, California;
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Hong SW, Lee J, Park SE, Rhee EJ, Park CY, Oh KW, Park SW, Lee WY. Activation of AMP-Activated Protein Kinase Attenuates Tumor Necrosis Factor-α-Induced Lipolysis via Protection of Perilipin in 3T3-L1 Adipocytes. Endocrinol Metab (Seoul) 2014; 29:553-60. [PMID: 25325265 PMCID: PMC4285046 DOI: 10.3803/enm.2014.29.4.553] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 04/11/2014] [Accepted: 04/24/2014] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Tumor necrosis factor (TNF)-α and AMP-activated protein kinase (AMPK) are known to stimulate and repress lipolysis in adipocytes, respectively; however, the mechanisms regulating these processes have not been completely elucidated. METHODS The key factors and mechanism of action of TNF-α and AMPK in lipolysis were investigated by evaluating perilipin expression and activity of protein kinase RNA-like endoplasmic reticulum kinase (PERK)/eukaryotic initiation factor 2 α (eIF2α) by Western blot and an immunofluorescence assay in 24-hour TNF-α-treated 3T3-L1 adipocytes with artificial manipulation of AMPK activation. RESULTS Enhancement of AMPK activity by the addition of activator minoimidazole carboxamide ribonucleotide (AICAR) suppressed TNF-α-induced lipolysis, whereas the addition of compound C, an inhibitor of AMPK phosphorylation, enhanced lipolysis. Perilipin, a lipid droplet-associated protein, was decreased by TNF-α and recovered following treatment with AICAR, showing a correlation with the antilipolytic effect of AICAR. Significant activation of PERK/eIF2α, a component of the unfolded protein response signaling pathway, was observed in TNF-α or vesicle-treated 3T3-L1 adipocytes. The antilipolytic effect and recovery of perilipin expression by AICAR in TNF-α-treated 3T3-L1 adipocytes were significantly diminished by treatment with 2-aminopurine, a specific inhibitor of eIF2α. CONCLUSION These data indicated that AICAR-induced AMPK activation attenuates TNF-α-induced lipolysis via preservation of perilipin in 3T3-L1 adipocytes. In addition, PERK/eIF2α activity is a novel mechanism of the anti-lipolytic effect of AICAR.
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Affiliation(s)
- Seok Woo Hong
- Institute of Medical Research, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jinmi Lee
- Institute of Medical Research, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Se Eun Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Eun Jung Rhee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Cheol Young Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ki Won Oh
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Sung Woo Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Won Young Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
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Abstract
Fat-specific protein 27 (FSP27) plays a pivotal role in controlling the formation of large lipid droplet and energy metabolism. The cellular levels of FSP27 are tightly regulated through the proteasomal ubiquitin-mediated degradation. However, the upstream signals that trigger FSP27 degradation and the underlying mechanism(s) have yet to be identified. Here we show that AMP-activated protein kinase (AMPK) activation by AICAR (5-amino-1-β-d-ribofuranosyl-imidazole-4-carboxamide) or phenformin induced the ubiquitination of FSP27 and promoted its degradation in 3T3-L1 adipocytes. The levels of FSP27 protein could be maintained by either knocking down AMPKα1 or blocking proteasomal pathway. Moreover, AICAR treatment induced multilocularization of LDs in 3T3-L1 adipocytes, reminiscent of the morphological changes in cells depleted of FSP27. Furthermore, mass spectrometry-based proteomic analysis identified heat shock cognate 70 (HSC70) as a novel binding protein of FSP27. The specific interaction was confirmed by co-immunoprecipitation of both ectopically expressed and endogenous proteins. Importantly, knockdown of HSC70 by small interference RNA resulted in increased half-life of FSP27 in cells treated with a protein synthesis inhibitor cycloheximide (CHX) or AICAR. However, silencing of the E3 ubiquitin ligase CHIP (COOH terminus of HSC70-interacting protein) failed to alter the stability of FSP27 protein under both conditions. Taken together, our data indicate that AMPK is a negative regulator of FSP27 stability through the proteasomal ubiquitin-dependent protein catabolic process. Promotion of FSP27 degradation may be an important factor responsible for the beneficial effect of AMPK activators on energy metabolism.
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Affiliation(s)
- Xiaodong Zhang
- Department of Biochemistry and Molecular Biology, HEAL Program, and
| | - Bradlee L Heckmann
- Department of Biochemistry and Molecular Biology, HEAL Program, and Mayo Graduate School, Rochester, Minnesota
| | - Xitao Xie
- Department of Biochemistry and Molecular Biology, HEAL Program, and
| | | | - Jun Liu
- Department of Biochemistry and Molecular Biology, HEAL Program, and Division of Endocrinology, Mayo Clinic in Arizona, Scottsdale, Arizona; and
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Almabrouk TAM, Ewart MA, Salt IP, Kennedy S. Perivascular fat, AMP-activated protein kinase and vascular diseases. Br J Pharmacol 2014; 171:595-617. [PMID: 24490856 DOI: 10.1111/bph.12479] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 10/04/2013] [Accepted: 10/16/2013] [Indexed: 12/15/2022] Open
Abstract
Perivascular adipose tissue (PVAT) is an active endocrine and paracrine organ that modulates vascular function, with implications for the pathophysiology of cardiovascular disease (CVD). Adipocytes and stromal cells contained within PVAT produce mediators (adipokines, cytokines, reactive oxygen species and gaseous compounds) with a range of paracrine effects modulating vascular smooth muscle cell contraction, proliferation and migration. However, the modulatory effect of PVAT on the vascular system in diseases, such as obesity, hypertension and atherosclerosis, remains poorly characterized. AMP-activated protein kinase (AMPK) regulates adipocyte metabolism, adipose biology and vascular function, and hence may be a potential therapeutic target for metabolic disorders such as type 2 diabetes mellitus (T2DM) and the vascular complications associated with obesity and T2DM. The role of AMPK in PVAT or the actions of PVAT have yet to be established, however. Activation of AMPK by pharmacological agents, such as metformin and thiazolidinediones, may modulate the activity of PVAT surrounding blood vessels and thereby contribute to their beneficial effect in cardiometabolic diseases. This review will provide a current perspective on how PVAT may influence vascular function via AMPK. We will also attempt to demonstrate how modulating AMPK activity using pharmacological agents could be exploited therapeutically to treat cardiometabolic diseases.
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Affiliation(s)
- T A M Almabrouk
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
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Abstract
When energy supply is low, organisms respond by slowing aging and increasing resistance to diverse age-related pathologies. Targeting the mechanisms underpinning this response may therefore treat multiple disorders through a single intervention. Here, we discuss AMP-activated protein kinase (AMPK) as an integrator and mediator of several pathways and processes linking energetics to longevity. Activated by low energy, AMPK is both prolongevity and druggable, but its role in some pathologies may not be beneficial. As such, activating AMPK may modulate multiple longevity pathways to promote healthy aging, but unlocking its full potential may require selective targeting toward substrates involved in longevity assurance.
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Affiliation(s)
| | - Yue Zhang
- Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
| | - William B Mair
- Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA.
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Wang L, Di L, Noguchi CT. AMPK is involved in mediation of erythropoietin influence on metabolic activity and reactive oxygen species production in white adipocytes. Int J Biochem Cell Biol 2014; 54:1-9. [PMID: 24953559 DOI: 10.1016/j.biocel.2014.06.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 05/29/2014] [Accepted: 06/15/2014] [Indexed: 12/15/2022]
Abstract
Erythropoietin, discovered for its indispensable role during erythropoiesis, has been used in therapy for selected red blood cell disorders in erythropoietin-deficient patients. The biological activities of erythropoietin have been found in animal models to extend to non-erythroid tissues due to the expression of erythropoietin receptor. We previously demonstrated that erythropoietin promotes metabolic activity and white adipocytes browning to increase mitochondrial function and energy expenditure via peroxisome proliferator-activated receptor alpha and Sirtuin1. Here we report that AMP-activated protein kinase was activated by erythropoietin possibly via Ca(2+)/calmodulin-dependent protein kinase kinase in adipocytes as well as in white adipose tissue from diet induced obese mice. Erythropoietin increased cellular nicotinamide adenine dinucleotide via increased AMP-activated protein kinase activity, possibly leading to Sirtuin1 activation. AMP-activated protein kinase knock down reduced erythropoietin mediated increase in cellular oxidative function including the increased oxygen consumption rate, fatty acid utilization and induction of key metabolic genes. Under hypoxia, adipocytes were found to generate more reactive oxygen species, and erythropoietin reduced the reactive oxygen species and increased antioxidant gene expression, suggesting that erythropoietin may provide protection from oxidative stress in adipocytes. Erythropoietin also reversed increased nicotinamide adenine dinucleotide by hypoxia via increased AMP-activated protein kinase. Additionally, AMP-activated protein kinase is found to be involved in erythropoietin stimulated increase in oxygen consumption rate, fatty acid oxidation and mitochondrial gene expression. AMP-activated protein kinase knock down impaired erythropoietin stimulated increases in antioxidant gene expression. Collectively, our findings identify the AMP-activated protein kinase involvement in erythropoietin signaling in regulating adipocyte cellular redox status and metabolic activity.
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Affiliation(s)
- Li Wang
- Faculty of Health Sciences, University of Macau, Macau SAR, China.
| | - Lijun Di
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Constance Tom Noguchi
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Building 10, Room 9N319, 10 CENTER DR MSC-1822, Bethesda, MD 20892-1822, USA.
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Nielsen TS, Jessen N, Jørgensen JOL, Møller N, Lund S. Dissecting adipose tissue lipolysis: molecular regulation and implications for metabolic disease. J Mol Endocrinol 2014; 52:R199-222. [PMID: 24577718 DOI: 10.1530/jme-13-0277] [Citation(s) in RCA: 263] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Lipolysis is the process by which triglycerides (TGs) are hydrolyzed to free fatty acids (FFAs) and glycerol. In adipocytes, this is achieved by sequential action of adipose TG lipase (ATGL), hormone-sensitive lipase (HSL), and monoglyceride lipase. The activity in the lipolytic pathway is tightly regulated by hormonal and nutritional factors. Under conditions of negative energy balance such as fasting and exercise, stimulation of lipolysis results in a profound increase in FFA release from adipose tissue (AT). This response is crucial in order to provide the organism with a sufficient supply of substrate for oxidative metabolism. However, failure to efficiently suppress lipolysis when FFA demands are low can have serious metabolic consequences and is believed to be a key mechanism in the development of type 2 diabetes in obesity. As the discovery of ATGL in 2004, substantial progress has been made in the delineation of the remarkable complexity of the regulatory network controlling adipocyte lipolysis. Notably, regulatory mechanisms have been identified on multiple levels of the lipolytic pathway, including gene transcription and translation, post-translational modifications, intracellular localization, protein-protein interactions, and protein stability/degradation. Here, we provide an overview of the recent advances in the field of AT lipolysis with particular focus on the molecular regulation of the two main lipases, ATGL and HSL, and the intracellular and extracellular signals affecting their activity.
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Affiliation(s)
- Thomas Svava Nielsen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, DenmarkThe Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Niels Jessen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, DenmarkThe Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Jens Otto L Jørgensen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Niels Møller
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Sten Lund
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
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135
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Abstract
In adipocytes the hydrolysis of TAG to produce fatty acids and glycerol under fasting conditions or times of elevated energy demands is tightly regulated by neuroendocrine signals, resulting in the activation of lipolytic enzymes. Among the classic regulators of lipolysis, adrenergic stimulation and the insulin-mediated control of lipid mobilisation are the best known. Initially, hormone-sensitive lipase (HSL) was thought to be the rate-limiting enzyme of the first lipolytic step, while we now know that adipocyte TAG lipase is the key enzyme for lipolysis initiation. Pivotal, previously unsuspected components have also been identified at the protective interface of the lipid droplet surface and in the signalling pathways that control lipolysis. Perilipin, comparative gene identification-58 (CGI-58) and other proteins of the lipid droplet surface are currently known to be key regulators of the lipolytic machinery, protecting or exposing the TAG core of the droplet to lipases. The neuroendocrine control of lipolysis is prototypically exerted by catecholaminergic stimulation and insulin-induced suppression, both of which affect cyclic AMP levels and hence the protein kinase A-mediated phosphorylation of HSL and perilipin. Interestingly, in recent decades adipose tissue has been shown to secrete a large number of adipokines, which exert direct effects on lipolysis, while adipocytes reportedly express a wide range of receptors for signals involved in lipid mobilisation. Recently recognised mediators of lipolysis include some adipokines, structural membrane proteins, atrial natriuretic peptides, AMP-activated protein kinase and mitogen-activated protein kinase. Lipolysis needs to be reanalysed from the broader perspective of its specific physiological or pathological context since basal or stimulated lipolytic rates occur under diverse conditions and by different mechanisms.
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136
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Abstract
The adenosine monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway arose early during evolution of eukaryotic cells, when it appears to have been involved in the response to glucose starvation and perhaps also in monitoring the output of the newly acquired mitochondria. Due to the advent of hormonal regulation of glucose homeostasis, glucose starvation is a less frequent event for mammalian cells than for single-celled eukaryotes. Nevertheless, the AMPK system has been preserved in mammals where, by monitoring cellular AMP:adenosine triphosphate (ATP) and adenosine diphosphate (ADP):ATP ratios and balancing the rates of catabolism and ATP consumption, it maintains energy homeostasis at a cell-autonomous level. In addition, hormones involved in maintaining energy balance at the whole-body level interact with AMPK in the hypothalamus. AMPK is activated by two widely used clinical drugs, metformin and aspirin, and also by many natural products of plants that are either derived from traditional medicines or are promoted as "nutraceuticals."
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Affiliation(s)
- D Grahame Hardie
- Division of Cell Signalling and Immunology, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, United Kingdom;
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137
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Chapnik N, Genzer Y, Ben-Shimon A, Niv MY, Froy O. AMPK-derived peptides reduce blood glucose levels but lead to fat retention in the liver of obese mice. J Endocrinol 2014; 221:89-99. [PMID: 24478381 DOI: 10.1530/joe-13-0625] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
AMP-activated protein kinase (AMPK) is a regulator of energy balance at both the cellular and the whole-body levels. Direct activation of AMPK has been highlighted as a potential novel, and possibly safer, alternative to treat type II diabetes and obesity. In this study, we aimed to design and characterize novel peptides that mimic the αG region of the α2 AMPK catalytic domain to modulate its activity by inhibiting interactions between AMPK domains or other interacting proteins. The derived peptides were tested in vivo and in tissue culture. The computationally predicted structure of the free peptide with the addition of the myristoyl (Myr) or acetyl (Ac) moiety closely resembled the protein structure that it was designed to mimic. Myr-peptide and Ac-peptide activated AMPK in muscle cells and led to reduced adipose tissue weight, body weight, blood glucose levels, insulin levels, and insulin resistance index, as expected from AMPK activation. In addition, triglyceride, cholesterol, leptin, and adiponectin levels were also lower, suggesting increased adipose tissue breakdown, a result of AMPK activation. On the other hand, liver weight and liver lipid content increased due to fat retention. We could not find an elevated pAMPK:AMPK ratio in the liver in vivo or in hepatocytes ex vivo, suggesting that the peptide does not lead to AMPK activation in hepatocytes. The finding that an AMPK-derived peptide leads to the activation of AMPK in muscle cells and in adipose tissue and leads to reduced glucose levels in obese mice, but to fat accumulation in the liver, demonstrates the differential effect of AMPK modulation in various tissues.
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Affiliation(s)
- Nava Chapnik
- Robert H. Smith Faculty of Agriculture, Food and Environment, Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot 76100, Israel Fritz Haber Center for Molecular Dynamics, The Hebrew University, Jerusalem, Israel
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138
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Niemann–Pick disease type C2 protein induces triglyceride accumulation in silkworm and mammalian cell lines. Biochem J 2014; 459:137-47. [DOI: 10.1042/bj20130876] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Niemann–Pick disease type C2 protein was identified as a triglyceride-accumulating factor in insect fluid.
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139
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Saremi B, Winand S, Friedrichs P, Kinoshita A, Rehage J, Dänicke S, Häussler S, Breves G, Mielenz M, Sauerwein H. Longitudinal profiling of the tissue-specific expression of genes related with insulin sensitivity in dairy cows during lactation focusing on different fat depots. PLoS One 2014; 9:e86211. [PMID: 24465964 PMCID: PMC3897665 DOI: 10.1371/journal.pone.0086211] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 12/09/2013] [Indexed: 01/13/2023] Open
Abstract
In dairy cows the milk associated energy output in early lactation exceeds the input via voluntary feed intake. To spare glucose for mammary lactose synthesis, peripheral insulin sensitivity (IS) is reduced and fat mobilization is stimulated. For these processes a link between IS and the endocrine functions of adipose tissue (AT) is likely; we thus aimed to characterise the mRNA expression from bovine AT derived proteins and receptors that are related to IS according to the literature in metabolically active tissues plus systemic IS throughout lactation. Conjugated linoleic acids (CLA) reduce milk fat thus decreasing the milk drain of energy and potentially dampening lipolysis, but may also affect IS. Subcutaneous (s.c.) AT and liver from pluriparous cows receiving either control fat or CLA supplement (100 g/day from 1 to 182 days in milk each) were biopsied covering week -3 to 36 relative to parturition. In an additional trial with primiparous cows treated analogously and slaughtered on days in milk 1, 42 or 105, samples from liver, udder, skeletal muscle and 3 visceral and 3 s.c. AT were obtained and assayed for mRNA abundance of adiponectin, its receptors, leptin, leptin receptor, PPARγ, PPARγ2, IL-6, and TNF-α. In pluriparous animals, the mRNA abundance of most of the target genes decreased after parturition in s.c. AT but increased in liver. In primiparous cows, AT depot specific differences were mostly related to retroperitoneal AT; adiponectin receptor 1 and TNF-α were affected predominantly. CLA effects in primiparous cows were largely limited to decreased PPARγ2 mRNA abundance in udder tissue. In pluriparous cows, insulin secretion was increased by CLA resulting in decreased systemic IS but without consistent changes in tissue target mRNA abundance. The temporal gene expression profiles from the adipokines and related receptors support their coactive function in adapting to the needs of lactation.
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Affiliation(s)
- Behnam Saremi
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, Bonn, Germany
| | - Sarah Winand
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, Bonn, Germany
| | - Paula Friedrichs
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, Bonn, Germany
| | - Asako Kinoshita
- Clinic for Cattle, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Jürgen Rehage
- Clinic for Cattle, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Sven Dänicke
- Institute of Animal Nutrition, Friedrich-Loeffler-Institute (FLI), Federal Research Institute for Animal Health, Braunschweig, Germany
| | - Susanne Häussler
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, Bonn, Germany
| | - Gerhard Breves
- Department of Physiology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Manfred Mielenz
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, Bonn, Germany
| | - Helga Sauerwein
- Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, Bonn, Germany
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140
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Purohit JS, Hu P, Chen G, Whelan J, Moustaid-Moussa N, Zhao L. Activation of nucleotide oligomerization domain containing protein 1 induces lipolysis through NF-κB and the lipolytic PKA activation in 3T3-L1 adipocytes. Biochem Cell Biol 2013; 91:428-34. [PMID: 24219284 DOI: 10.1139/bcb-2013-0049] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Obesity is associated with chronic inflammation. Toll-like receptors (TLR) and NOD-like receptors (NLR) are two families of pattern recognition receptors that play important roles in the immune response and inflammation in adipocytes. Activation of TLR4 has been shown to stimulate lipolysis from adipose tissue or adipocytes. However, effects of activation of nucleotide-oligomerization domain containing protein 1 (NOD1), one of the prominent members of NLRs, on adipocyte lipolysis have not been studied. Here we report that NOD1 activation by the synthetic ligands (Tri-DAP and C12-iEDAP) stimulated lipolysis in 3T3-L1 adipocytes in a time- and dose-dependent manner. C12-iEDAP-induced lipolysis was attenuated with NOD1 siRNA knockdown, demonstrating the specificity of the effects. Moreover, inhibition of the protein kinase A (PKA)/hormone sensitive lipase (HSL) and NF-κB pathways by the pharmacological inhibitors attenuated the lipolytic effects of C12-iEDAP. Furthermore, we show NOD1 activation induced PKA activation independent of cAMP production and inhibition of NF-κB pathways attenuated phosphorylation of selected PKA lipolytic targets (phosphorylation of Perilipin Ser 517 and HSL Ser 563). Taken together, our results demonstrate a novel role of NOD1 activation, via NF-κB/PKA lipolytic activation, in inducing lipolysis in adipocytes and suggest that NOD1 activation may contribute to dyslipidemia in obesity.
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Affiliation(s)
- Jaanki S Purohit
- a Department of Nutrition, University of Tennessee, 1215 W. Cumberland Ave., Knoxville, TN, USA
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141
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Cignarelli A, Giorgino F, Vettor R. Pharmacologic agents for type 2 diabetes therapy and regulation of adipogenesis. Arch Physiol Biochem 2013; 119:139-50. [PMID: 23724947 DOI: 10.3109/13813455.2013.796996] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The close link between type 2 diabetes and excess body weight highlights the need to consider the effects on weight of different treatments used for correction of hyperglycaemia. Indeed, specific currently available diabetes therapies can cause weight gain, including insulin and its analogues, sulphonylureas, and thiazolidinediones, while others, such as metformin and the GLP-1 receptor agonists, can promote weight loss. Excess body weight in patients with diabetes is largely due to expansion of adipose tissue, and these drugs could interfere with the mechanisms underlying the expansion and differentiation of adipocyte precursors. Almost all anti-diabetes drugs could also potentially affect adipocyte metabolism directly, by modulating lipogenesis, lipolysis, and fat oxidation. This review will examine the available evidence for specific effects of various anti-diabetes drugs on adipose tissue development and function with the ultimate goal of increasing our understanding of how pharmacological agents can modulate energy balance and body fat.
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Affiliation(s)
- A Cignarelli
- Department of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology, Andrology, and Metabolic Diseases, University of Bari "Aldo Moro" , Bari , Italy and
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142
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Steinberg GR, Dandapani M, Hardie DG. AMPK: mediating the metabolic effects of salicylate-based drugs? Trends Endocrinol Metab 2013; 24:481-7. [PMID: 23871515 PMCID: PMC5714185 DOI: 10.1016/j.tem.2013.06.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 06/11/2013] [Accepted: 06/13/2013] [Indexed: 12/21/2022]
Abstract
Salicylates are among the oldest medicinal compounds known to humans, and have been used to reduce fever, pain, and inflammation. The major oral salicylates are aspirin and salsalate, both of which are rapidly metabolized to salicylate in vivo. Owing to its acetyl group, aspirin irreversibly inhibits cyclo-oxygenases and thus blocks platelet aggregation, whereas salsalate has been used for treatment of inflammatory diseases such as rheumatoid arthritis. Recently, beneficial effects of salicylates in type 2 diabetes and cancer have been proposed. This has led to renewed interest in understanding how these simple molecules have such diverse and multifaceted effects. Here we discuss the idea that AMP-activated protein kinase (AMPK) might mediate some effects of salicylate-based drugs, particularly by modulating cellular metabolism.
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Affiliation(s)
- Gregory R. Steinberg
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, 1280 Main St. W., Hamilton, Ontario, Canada L8N 3Z5
| | - Madhumita Dandapani
- Division of Cell Signaling & Immunology, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, UK
| | - D. Grahame Hardie
- Division of Cell Signaling & Immunology, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, UK
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143
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Zhang X, Wang Z, Li J, Gu D, Li S, Shen C, Song Z. Increased 4-hydroxynonenal formation contributes to obesity-related lipolytic activation in adipocytes. PLoS One 2013; 8:e70663. [PMID: 23940618 PMCID: PMC3734238 DOI: 10.1371/journal.pone.0070663] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 06/20/2013] [Indexed: 12/20/2022] Open
Abstract
Oxidative stress in adipose tissue plays an etiological role in a variety of obesity-related metabolic disorders. We previously reported that increased adipose tissue 4-hydroxynonenal (4-HNE) contents contributed to obesity-related plasma adiponectin decline in mice. In the present study, we investigated the effects of intracellular 4-HNE accumulation on lipolytic response in adipocytes/adipose tissues and underlying mechanisms. In both fully-differentiated 3T3-L1 and primary adipocytes, a 5-hour 4-HNE exposure elevated lipolytic reaction in a dose-dependent manner at both basal and isoproterenol-stimulated conditions, evidenced by significantly increased glycerol and fatty acids releases. This conclusion was corroborated by the comparable observations when the minced human visceral adipose tissues were used. Mechanistic investigations revealed that 4-HNE-stimulated lipolytic activation is multifactorial. 4-HNE exposure quickly increased intracellular cyclic AMP (cAMP) level, which was concomitant with increased phosphorylations of protein kinase A (PKA) and its direct downstream target, hormone sensitive lipase (HSL). Pre-incubation with H89, a potent PKA inhibitor, prevented 4-HNE stimulated glycerol release, suggesting that enhanced lipolytic action in response to 4-HNE increase is mediated mainly by cAMP/PKA signal pathway in adipocytes. In addition to activating cAMP/PKA/HSL pathway, 4-HNE exposure also suppresses AMP-activated protein kinase (AMPK), a suppressive pathway for lipolysis, measured by both Western blotting for phosphorylated form of AMPK and ELISA for enzyme activity. Furthermore, 5-Aminoimidazole-4-carboxamide 1-beta-D-ribofuranoside (AICAR), a pharmacological AMPK activator, alleviated 4-HNE-induced lipolysis, suggesting that AMPK suppression also contributes to 4-HNE elicited lipolytic response. In conclusion, our findings indicate that increased intracellular 4-HNE accumulation in adipocytes/adipose tissues contributes to obesity-related lipolytic activation.
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Affiliation(s)
- Ximei Zhang
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Histology and Embryology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Zhigang Wang
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Jiaxin Li
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Dongfang Gu
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Songtao Li
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Chen Shen
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Zhenyuan Song
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Department of Pathology, University of Illinois Medical Center, Chicago, Illinois, United States of America
- * E-mail:
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144
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Li Y, Nie Y, Helou Y, Ding G, Feng B, Xu G, Salomon A, Xu H. Identification of sucrose non-fermenting-related kinase (SNRK) as a suppressor of adipocyte inflammation. Diabetes 2013; 62:2396-409. [PMID: 23520131 PMCID: PMC3712026 DOI: 10.2337/db12-1081] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 03/13/2013] [Indexed: 01/10/2023]
Abstract
In this study, the role of sucrose non-fermenting-related kinase (SNRK) in white adipocyte biology was investigated. SNRK is abundantly expressed in adipose tissue, and the expression level is decreased in obese mice. SNRK expression is repressed by inflammatory signals but increased by insulin sensitizer in cultured adipocytes. In vivo, adipose tissue SNRK expression can be decreased by lipid injection but enhanced by macrophage ablation. Knocking down SNRK in cultured adipocytes activates both JNK and IKKβ pathways as well as promotes lipolysis. Insulin-stimulated Akt phosphorylation and glucose uptake are impaired in SNRK knockdown adipocytes. Phosphoproteomic analysis with SNRK knockdown adipocytes revealed significantly decreased phosphorylation of 49 proteins by 25% or more, which are involved in various aspects of adipocyte function with a clear indication of attenuated mTORC1 signaling. Phosphorylation of 43 proteins is significantly increased by onefold or higher, among which several proteins are known to be involved in inflammatory pathways. The inflammatory responses in SNRK knockdown adipocytes can be partially attributable to defective mTORC1 signaling, since rapamycin treatment activates IKKβ and induces lipolysis in adipocytes. In summary, SNRK may act as a suppressor of adipocyte inflammation and its presence is necessary for maintaining normal adipocyte function.
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Affiliation(s)
- Yujie Li
- Hallett Center for Diabetes and Endocrinology, Rhode Island Hospital, Warren Alpert
- Department of Geriatric Endocrinology, Jiangsu Province Hospital, Nanjing Medical University, Nanjing, China
| | - Yaohui Nie
- Hallett Center for Diabetes and Endocrinology, Rhode Island Hospital, Warren Alpert
- Department of Medicine and Therapeutics, The Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Ynes Helou
- Department of Molecular Pharmacology and Physiology, Brown University, Providence, Rhode Island
| | - Guoxian Ding
- Department of Geriatric Endocrinology, Jiangsu Province Hospital, Nanjing Medical University, Nanjing, China
| | - Bin Feng
- Hallett Center for Diabetes and Endocrinology, Rhode Island Hospital, Warren Alpert
| | - Gang Xu
- Department of Medicine and Therapeutics, The Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Arthur Salomon
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island
- Department of Chemistry, Brown University, Providence, Rhode Island
| | - Haiyan Xu
- Hallett Center for Diabetes and Endocrinology, Rhode Island Hospital, Warren Alpert
- Pathobiology Program, Brown University, Providence, Rhode Island
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145
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Czech MP, Tencerova M, Pedersen DJ, Aouadi M. Insulin signalling mechanisms for triacylglycerol storage. Diabetologia 2013; 56:949-64. [PMID: 23443243 PMCID: PMC3652374 DOI: 10.1007/s00125-013-2869-1] [Citation(s) in RCA: 178] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 01/22/2013] [Indexed: 02/06/2023]
Abstract
Insulin signalling is uniquely required for storing energy as fat in humans. While de novo synthesis of fatty acids and triacylglycerol occurs mostly in liver, adipose tissue is the primary site for triacylglycerol storage. Insulin signalling mechanisms in adipose tissue that stimulate hydrolysis of circulating triacylglycerol, uptake of the released fatty acids and their conversion to triacylglycerol are poorly understood. New findings include (1) activation of DNA-dependent protein kinase to stimulate upstream stimulatory factor (USF)1/USF2 heterodimers, enhancing the lipogenic transcription factor sterol regulatory element binding protein 1c (SREBP1c); (2) stimulation of fatty acid synthase through AMP kinase modulation; (3) mobilisation of lipid droplet proteins to promote retention of triacylglycerol; and (4) upregulation of a novel carbohydrate response element binding protein β isoform that potently stimulates transcription of lipogenic enzymes. Additionally, insulin signalling through mammalian target of rapamycin to activate transcription and processing of SREBP1c described in liver may apply to adipose tissue. Paradoxically, insulin resistance in obesity and type 2 diabetes is associated with increased triacylglycerol synthesis in liver, while it is decreased in adipose tissue. This and other mysteries about insulin signalling and insulin resistance in adipose tissue make this topic especially fertile for future research.
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Affiliation(s)
- M P Czech
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA.
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146
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Flachs P, Rossmeisl M, Kuda O, Kopecky J. Stimulation of mitochondrial oxidative capacity in white fat independent of UCP1: A key to lean phenotype. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:986-1003. [DOI: 10.1016/j.bbalip.2013.02.003] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 02/06/2013] [Accepted: 02/09/2013] [Indexed: 02/06/2023]
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147
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Isoproterenol instigates cardiomyocyte apoptosis and heart failure via AMPK inactivation-mediated endoplasmic reticulum stress. Apoptosis 2013; 18:800-10. [DOI: 10.1007/s10495-013-0843-5] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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148
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Bijland S, Mancini SJ, Salt IP. Role of AMP-activated protein kinase in adipose tissue metabolism and inflammation. Clin Sci (Lond) 2013; 124:491-507. [PMID: 23298225 DOI: 10.1042/cs20120536] [Citation(s) in RCA: 225] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
AMPK (AMP-activated protein kinase) is a key regulator of cellular and whole-body energy balance. AMPK phosphorylates and regulates many proteins concerned with nutrient metabolism, largely acting to suppress anabolic ATP-consuming pathways while stimulating catabolic ATP-generating pathways. This has led to considerable interest in AMPK as a therapeutic target for the metabolic dysfunction observed in obesity and insulin resistance. The role of AMPK in skeletal muscle and the liver has been extensively studied, such that AMPK has been demonstrated to inhibit synthesis of fatty acids, cholesterol and isoprenoids, hepatic gluconeogenesis and translation while increasing fatty acid oxidation, muscle glucose transport, mitochondrial biogenesis and caloric intake. The role of AMPK in the other principal metabolic and insulin-sensitive tissue, adipose, remains poorly characterized in comparison, yet increasing evidence supports an important role for AMPK in adipose tissue function. Obesity is characterized by hypertrophy of adipocytes and the development of a chronic sub-clinical pro-inflammatory environment in adipose tissue, leading to increased infiltration of immune cells. This combination of dysfunctional hypertrophic adipocytes and a pro-inflammatory environment contributes to insulin resistance and the development of Type 2 diabetes. Exciting recent studies indicate that AMPK may not only influence metabolism in adipocytes, but also act to suppress this pro-inflammatory environment, such that targeting AMPK in adipose tissue may be desirable to normalize adipose dysfunction and inflammation. In the present review, we discuss the role of AMPK in adipose tissue, focussing on the regulation of carbohydrate and lipid metabolism, adipogenesis and pro-inflammatory pathways in physiological and pathophysiological conditions.
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Affiliation(s)
- Silvia Bijland
- Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
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149
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Ceddia RB. The role of AMP-activated protein kinase in regulating white adipose tissue metabolism. Mol Cell Endocrinol 2013; 366:194-203. [PMID: 22750051 DOI: 10.1016/j.mce.2012.06.014] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 03/16/2012] [Accepted: 06/21/2012] [Indexed: 01/19/2023]
Abstract
AMP-activated protein kinase (AMPK) is a heterotrimeric enzyme that plays a major role in the maintenance of energy homeostasis in various organs and tissues. When activated, AMPK can induce substrate catabolism and shut down energy-consuming anabolic pathways to increase intracellular ATP availability. Even though most of these effects have been described in muscle and liver, several studies have provided compelling evidence that AMPK also plays an important role in the regulation of white adipose tissue (WAT) glucose and lipid metabolism. In fact, the effects of acute and chronic AMPK activation in the WAT induce profound changes in adiposity with important implications for the treatment of obesity and its related metabolic disorders. This review discusses the role of AMPK in the regulation of white adipocyte metabolism with respect to energy storage and release, gene expression, mitochondrial biogenesis, oxidative capacity, cell differentiation, and the potential impact on whole-body adiposity and energy homeostasis.
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Affiliation(s)
- R B Ceddia
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada.
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150
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Nagendran J, Waller TJ, Dyck JRB. AMPK signalling and the control of substrate use in the heart. Mol Cell Endocrinol 2013; 366:180-93. [PMID: 22750050 DOI: 10.1016/j.mce.2012.06.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 03/29/2012] [Accepted: 06/21/2012] [Indexed: 12/21/2022]
Abstract
All mammalian cells rely on adenosine triphosphate (ATP) to maintain function and for survival. The heart has the highest basal ATP demand of any organ due to the necessity for continuous contraction. As such, the ability of the cardiomyocyte to monitor cellular energy status and adapt the supply of substrates to match the energy demand is crucial. One important serine/threonine protein kinase that monitors cellular energy status in the heart is adenosine monophosphate activated protein kinase (AMPK). AMPK is also a key enzyme that controls multiple catabolic and anabolic biochemical pathways in the heart and indirectly plays a crucial role in regulating cardiac function in both physiological and pathophysiological conditions. Herein, we review the involvement of AMPK in myocardial fatty acid and glucose transport and utilization, as it relates to basal cardiac function. We also assess the literature amassed on cardiac AMPK and discuss the controversies surrounding the role of AMPK in physiological and pathophysiological processes in the heart. The work reviewed herein also emphasizes areas that require further investigation for the purpose of eventually translating this information into improved patient care.
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Affiliation(s)
- Jeevan Nagendran
- Cardiovascular Research Centre, Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
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