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Lustig RH, Collier D, Kassotis C, Roepke TA, Ji Kim M, Blanc E, Barouki R, Bansal A, Cave MC, Chatterjee S, Choudhury M, Gilbertson M, Lagadic-Gossmann D, Howard S, Lind L, Tomlinson CR, Vondracek J, Heindel JJ. Obesity I: Overview and molecular and biochemical mechanisms. Biochem Pharmacol 2022; 199:115012. [PMID: 35393120 PMCID: PMC9050949 DOI: 10.1016/j.bcp.2022.115012] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/12/2022] [Accepted: 03/15/2022] [Indexed: 02/06/2023]
Abstract
Obesity is a chronic, relapsing condition characterized by excess body fat. Its prevalence has increased globally since the 1970s, and the number of obese and overweight people is now greater than those underweight. Obesity is a multifactorial condition, and as such, many components contribute to its development and pathogenesis. This is the first of three companion reviews that consider obesity. This review focuses on the genetics, viruses, insulin resistance, inflammation, gut microbiome, and circadian rhythms that promote obesity, along with hormones, growth factors, and organs and tissues that control its development. It shows that the regulation of energy balance (intake vs. expenditure) relies on the interplay of a variety of hormones from adipose tissue, gastrointestinal tract, pancreas, liver, and brain. It details how integrating central neurotransmitters and peripheral metabolic signals (e.g., leptin, insulin, ghrelin, peptide YY3-36) is essential for controlling energy homeostasis and feeding behavior. It describes the distinct types of adipocytes and how fat cell development is controlled by hormones and growth factors acting via a variety of receptors, including peroxisome proliferator-activated receptor-gamma, retinoid X, insulin, estrogen, androgen, glucocorticoid, thyroid hormone, liver X, constitutive androstane, pregnane X, farnesoid, and aryl hydrocarbon receptors. Finally, it demonstrates that obesity likely has origins in utero. Understanding these biochemical drivers of adiposity and metabolic dysfunction throughout the life cycle lends plausibility and credence to the "obesogen hypothesis" (i.e., the importance of environmental chemicals that disrupt these receptors to promote adiposity or alter metabolism), elucidated more fully in the two companion reviews.
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Affiliation(s)
- Robert H Lustig
- Division of Endocrinology, Department of Pediatrics, University of California, San Francisco, CA 94143, United States
| | - David Collier
- Brody School of Medicine, East Carolina University, Greenville, NC 27834, United States
| | - Christopher Kassotis
- Institute of Environmental Health Sciences and Department of Pharmacology, Wayne State University, Detroit, MI 48202, United States
| | - Troy A Roepke
- School of Environmental and Biological Sciences, Rutgers University, New Brunswick, NJ 08901, United States
| | - Min Ji Kim
- Department of Biochemistry and Toxicology, University of Paris, INSERM U1224 (T3S), 75006 Paris, France
| | - Etienne Blanc
- Department of Biochemistry and Toxicology, University of Paris, INSERM U1224 (T3S), 75006 Paris, France
| | - Robert Barouki
- Department of Biochemistry and Toxicology, University of Paris, INSERM U1224 (T3S), 75006 Paris, France
| | - Amita Bansal
- College of Health & Medicine, Australian National University, Canberra, Australia
| | - Matthew C Cave
- Division of Gastroenterology, Hepatology and Nutrition, University of Louisville, Louisville, KY 40402, United States
| | - Saurabh Chatterjee
- Environmental Health and Disease Laboratory, University of South Carolina, Columbia, SC 29208, United States
| | - Mahua Choudhury
- College of Pharmacy, Texas A&M University, College Station, TX 77843, United States
| | - Michael Gilbertson
- Occupational and Environmental Health Research Group, University of Stirling, Stirling, Scotland, United Kingdom
| | - Dominique Lagadic-Gossmann
- Research Institute for Environmental and Occupational Health, University of Rennes, INSERM, EHESP, Rennes, France
| | - Sarah Howard
- Healthy Environment and Endocrine Disruptor Strategies, Commonweal, Bolinas, CA 92924, United States
| | - Lars Lind
- Department of Medical Sciences, University of Uppsala, Uppsala, Sweden
| | - Craig R Tomlinson
- Norris Cotton Cancer Center, Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, United States
| | - Jan Vondracek
- Department of Cytokinetics, Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
| | - Jerrold J Heindel
- Healthy Environment and Endocrine Disruptor Strategies, Commonweal, Bolinas, CA 92924, United States.
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Sharma S, Shen T, Chitranshi N, Gupta V, Basavarajappa D, Mirzaei M, You Y, Krezel W, Graham SL, Gupta V. Retinoid X Receptor: Cellular and Biochemical Roles of Nuclear Receptor with a Focus on Neuropathological Involvement. Mol Neurobiol 2022; 59:2027-2050. [PMID: 35015251 PMCID: PMC9015987 DOI: 10.1007/s12035-021-02709-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/21/2021] [Indexed: 12/13/2022]
Abstract
Retinoid X receptors (RXRs) present a subgroup of the nuclear receptor superfamily with particularly high evolutionary conservation of ligand binding domain. The receptor exists in α, β, and γ isotypes that form homo-/heterodimeric complexes with other permissive and non-permissive receptors. While research has identified the biochemical roles of several nuclear receptor family members, the roles of RXRs in various neurological disorders remain relatively under-investigated. RXR acts as ligand-regulated transcription factor, modulating the expression of genes that plays a critical role in mediating several developmental, metabolic, and biochemical processes. Cumulative evidence indicates that abnormal RXR signalling affects neuronal stress and neuroinflammatory networks in several neuropathological conditions. Protective effects of targeting RXRs through pharmacological ligands have been established in various cell and animal models of neuronal injury including Alzheimer disease, Parkinson disease, glaucoma, multiple sclerosis, and stroke. This review summarises the existing knowledge about the roles of RXR, its interacting partners, and ligands in CNS disorders. Future research will determine the importance of structural and functional heterogeneity amongst various RXR isotypes as well as elucidate functional links between RXR homo- or heterodimers and specific physiological conditions to increase drug targeting efficiency in pathological conditions.
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Affiliation(s)
- Samridhi Sharma
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia.
| | - Ting Shen
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Nitin Chitranshi
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Veer Gupta
- School of Medicine, Deakin University, Melbourne, VIC, Australia
| | - Devaraj Basavarajappa
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Mehdi Mirzaei
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Yuyi You
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia.,Save Sight Institute, University of Sydney, Sydney, NSW, Australia
| | - Wojciech Krezel
- Institut de Génétique Et de Biologie Moléculaire Et Cellulaire, INSERM U1258, CNRS UMR 7104, Unistra, 67404, Illkirch-Graffenstaden, France
| | - Stuart L Graham
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia.,Save Sight Institute, University of Sydney, Sydney, NSW, Australia
| | - Vivek Gupta
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia.
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Kassotis CD, Stapleton HM. Endocrine-Mediated Mechanisms of Metabolic Disruption and New Approaches to Examine the Public Health Threat. Front Endocrinol (Lausanne) 2019; 10:39. [PMID: 30792693 PMCID: PMC6374316 DOI: 10.3389/fendo.2019.00039] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 01/17/2019] [Indexed: 01/29/2023] Open
Abstract
Obesity and metabolic disorders are of great societal concern and generate substantial human health care costs globally. Interventions have resulted in only minimal impacts on disrupting this worsening health trend, increasing attention on putative environmental contributors. Exposure to numerous environmental contaminants have, over decades, been demonstrated to result in increased metabolic dysfunction and/or weight gain in cell and animal models, and in some cases, even in humans. There are numerous mechanisms through which environmental contaminants may contribute to metabolic dysfunction, though certain mechanisms, such as activation of the peroxisome proliferator activated receptor gamma or the retinoid x receptor, have received considerably more attention than less-studied mechanisms such as antagonism of the thyroid receptor, androgen receptor, or mitochondrial toxicity. As such, research on putative metabolic disruptors is growing rapidly, as is our understanding of molecular mechanisms underlying these effects. Concurrent with these advances, new research has evaluated current models of adipogenesis, and new models have been proposed. Only in the last several years have studies really begun to address complex mixtures of contaminants and how these mixtures may disrupt metabolic health in environmentally relevant exposure scenarios. Several studies have begun to assess environmental mixtures from various environments and study the mechanisms underlying their putative metabolic dysfunction; these studies hold real promise in highlighting crucial mechanisms driving observed organismal effects. In addition, high-throughput toxicity databases (ToxCast, etc.) may provide future benefits in prioritizing chemicals for in vivo testing, particularly once the causative molecular mechanisms promoting dysfunction are better understood and expert critiques are used to hone the databases. In this review, we will review the available literature linking metabolic disruption to endocrine-mediated molecular mechanisms, discuss the novel application of environmental mixtures and implications for in vivo metabolic health, and discuss the putative utility of applying high-throughput toxicity databases to answering complex organismal health outcome questions.
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Takenaka Y, Inoue I, Nakano T, Ikeda M, Kakinuma Y, Ikegami Y, Shimada A, Noda M. Evaluation of Teneligliptin Effects on Transcriptional Activity of PPARγ in Cell-Based Assays. J NIPPON MED SCH 2018; 85:95-101. [PMID: 29731503 DOI: 10.1272/jnms.2018_85-15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND The antidiabetic drug teneligliptin is a novel dipeptidyl peptidase-4 (DPP-4) inhibitor with a thiazolidine-specific structure. This study aimed to investigate whether teneligliptin can activate PPARγ directly and/or indirectly in cell-based assays. METHODS Promoter assays using the reporter construct driven under the control of the SV40 promoter and the PPAR response element (PPRE) were performed. Luciferase activity was measured after a 3-day incubation of vector-transduced cells with various concentrations of teneligliptin. RESULTS Treatment of the cells with 50 μM teneligliptin significantly transactivated a reporter gene. The presence of the PPARγ antagonist, GW9662, did not affect the activation of PPRE-reporter expression by teneligliptin. CONCLUSION We found that teneligliptin could increase PPARγ activity in cell-based assays irrespective of the PPARγ ligand-binding domain.
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Affiliation(s)
- Yasuhiro Takenaka
- Department of Physiology, Graduate School of Medicine, Nippon Medical School
| | - Ikuo Inoue
- Department of Diabetes and Endocrinology, Saitama Medical University
| | | | - Masaaki Ikeda
- Department of Physiology, Saitama Medical University
| | - Yoshihiko Kakinuma
- Department of Physiology, Graduate School of Medicine, Nippon Medical School
| | - Yuichi Ikegami
- Department of Diabetes and Endocrinology, Saitama Medical University
| | - Akira Shimada
- Department of Diabetes and Endocrinology, Saitama Medical University
| | - Mitsuhiko Noda
- Department of Diabetes and Endocrinology, Saitama Medical University
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Lee YS, Choi SS, Yonezawa T, Teruya T, Woo JT, Kim HJ, Cha BY. Honokiol, magnolol, and a combination of both compounds improve glucose metabolism in high-fat diet-induced obese mice. Food Sci Biotechnol 2015. [DOI: 10.1007/s10068-015-0189-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Lee W, Ham J, Kwon HC, Yoon G, Bae GU, Kim YK, Kim SN. Amorphastilbol exerts beneficial effects on glucose and lipid metabolism in mice consuming a high-fat-diet. Int J Mol Med 2015; 36:527-33. [PMID: 26035293 DOI: 10.3892/ijmm.2015.2227] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 05/21/2015] [Indexed: 11/06/2022] Open
Abstract
In the present study, the anti-diabetic effects of amorphastilbol (APH) from Amorpha fruticosa (AF) were evaluated in high-fat-diet (HFD) mice. HFD-induced blood glucose and insulin levels are significantly reduced in AF extract or APH treatment groups. HFD-induced weight gain was reduced by AF treatment, which is accompanied by reduction of fat mass and adipocyte size and number in white adipose tissues. Furthermore, total cholesterol and low-density lipoprotein-cholesterol levels are decreased in AF- or APH-treated mice. In addition, AF and APH are able to improve insulin sensitivity through inhibition of protein tyrosine phosphatase 1B, a negative regulator of the insulin-signaling pathway. Taken together, the data suggest that AF has beneficial effects on glucose and lipid metabolism and its pharmacological effects are driven, in part, by its active component, APH. Therefore, AF and APH can be used as potential therapeutic agents against type 2 diabetes and associated metabolic disorders, including obesity, by enhancing glucose and lipid metabolism.
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Affiliation(s)
- Woojung Lee
- Natural Medicine Center, KIST Gangneung Institute, Gangneung, Gangwon 210-340, Republic of Korea
| | - Jungyeob Ham
- Natural Medicine Center, KIST Gangneung Institute, Gangneung, Gangwon 210-340, Republic of Korea
| | - Hak Cheol Kwon
- Natural Medicine Center, KIST Gangneung Institute, Gangneung, Gangwon 210-340, Republic of Korea
| | - Goo Yoon
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Jeonnam 534-729, Republic of Korea
| | - Gyu-Un Bae
- Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women's University, Seoul 140-742, Republic of Korea
| | - Yong Kee Kim
- Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women's University, Seoul 140-742, Republic of Korea
| | - Su-Nam Kim
- Natural Medicine Center, KIST Gangneung Institute, Gangneung, Gangwon 210-340, Republic of Korea
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de Picoli Souza K, da Silva ED, Batista EC, Reis FCG, Silva SMA, Castro CHM, Luz J, Pesquero JL, Dos Santos EL, Pesquero JB. Early pharmacological inhibition of angiotensin-I converting enzyme activity induces obesity in adulthood. Front Pharmacol 2015; 6:75. [PMID: 25926796 PMCID: PMC4396349 DOI: 10.3389/fphar.2015.00075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 03/19/2015] [Indexed: 01/05/2023] Open
Abstract
We have investigated early programming of body mass in order to understand the multifactorial etiology of obesity. Considering that the renin-angiotensin system (RAS) is expressed and functional in the white adipose tissue (WAT) and modulates its development, we reasoned whether early transitory inhibition of angiotensin-I converting enzyme activity after birth could modify late body mass development. Therefore, newborn Wistar rats were treated with enalapril (10 mg/kg of body mass) or saline, starting at the first day of life until the age of 16 days. Between days ninetieth and hundred and eightieth, a group of these animals received high fat diet (HFD). Molecular, biochemical, histological, and physiological data were collected. Enalapril treated animals presented hyperphagia, overweight, and increased serum level of triglycerides, total cholesterol and leptin, in adult life. Body composition analyses revealed higher fat mass with increased adipocyte size in these animals. Molecular analyses revealed that enalapril treatment increases neuropeptide Y (NPY) and cocaine- and amphetamine-regulated transcript (CART) gene expression in hypothalamus, fatty acid synthase (FAS), and hormone-sensitive lipase (HSL) gene expression in retroperitoneal WAT, and decreases peroxixome proliferators-activated receptor (PPAR)γ, PPARα, uncoupling protein (UCP)2, and UCP3 gene expression in WAT. The results of the current study indicate that enalapril administration during early postnatal development increases body mass, adiposity and serum lipids in adulthood associated with enhanced food intake and decreased metabolic activity in WAT, predisposing to obesity in adulthood.
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Affiliation(s)
- Kely de Picoli Souza
- School of Environmental and Biological Science, Universidade Federal da Grande Dourados Dourados, Brazil
| | - Elton D da Silva
- Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo São Paulo, Brazil
| | - Elice C Batista
- Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo São Paulo, Brazil
| | - Felipe C G Reis
- Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo São Paulo, Brazil
| | - Sylvia M A Silva
- Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo São Paulo, Brazil
| | - Charlles H M Castro
- Department of Rheumatology, Escola Paulista de Medicina, Universidade Federal de São Paulo São Paulo, Brazil
| | - Jaqueline Luz
- Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo São Paulo, Brazil
| | - Jorge L Pesquero
- Department of Physiology and Biophysics, Universidade Federal de Minas Gerais Belo Horizonte, Brazil
| | - Edson L Dos Santos
- School of Environmental and Biological Science, Universidade Federal da Grande Dourados Dourados, Brazil
| | - João B Pesquero
- Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo São Paulo, Brazil
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Nitrooleic Acid Attenuates Lipid Metabolic Disorders and Liver Steatosis in DOCA-Salt Hypertensive Mice. PPAR Res 2015; 2015:480348. [PMID: 25861250 PMCID: PMC4377523 DOI: 10.1155/2015/480348] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Accepted: 09/14/2014] [Indexed: 11/17/2022] Open
Abstract
Nitrooleic acid (OA-NO2) is endogenous ligands for peroxisome proliferator-activated receptors. The present study was aimed at investigating the beneficial effects of OA-NO2 on the lipid metabolism and liver steatosis in deoxycorticosterone acetate- (DOCA-) salt induced hypertensive mice model. Male C57BL/6 mice were divided to receive DOCA-salt plus OA-NO2 or DOCA-salt plus vehicle and another group received neither DOCA-salt nor OA-NO2 (control group). After 3-week treatment with DOCA-salt plus 1% sodium chloride in drinking fluid, the hypertension was noted; however, OA-NO2 had no effect on the hypertension. In DOCA-salt treated mice, the plasma triglyceride and total cholesterol levels were significantly increased compared to control mice, and pretreatment with OA-NO2 significantly reduced these parameters. Further, the histopathology of liver exhibited more lipid distribution together with more serious micro- and macrovesicular steatosis after DOCA-salt treatment and that was consistent with liver tissue triglyceride and nonesterified fatty acids (NEFA) content. The mice pretreated with OA-NO2 showed reduced liver damage accompanied with low liver lipid content. Moreover, the liver TBARS, together with the expressions of gp91phox and p47phox, were parallelly decreased. These findings indicated that OA-NO2 had the protective effect on liver injury against DOCA-salt administration and the beneficial effect could be attributed to its antihyperlipidemic activities.
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Anti-diabetic effect of amorphastilbol through PPARα/γ dual activation in db/db mice. Biochem Biophys Res Commun 2013; 432:73-9. [DOI: 10.1016/j.bbrc.2013.01.083] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 01/16/2013] [Indexed: 01/31/2023]
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Rossmeisl M, Kovar J, Syrovy I, Flachs P, Bobkova D, Kolar F, Poledne R, Kopecky J. Triglyceride-lowering Effect of Respiratory Uncoupling in White Adipose Tissue. ACTA ACUST UNITED AC 2012; 13:835-44. [PMID: 15919836 DOI: 10.1038/oby.2005.96] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE Hypolipidemic drugs such as bezafibrate and thiazolidinediones are known to induce the expression of mitochondrial uncoupling proteins (UCPs) in white adipose tissue. To analyze the potential triglyceride (TG)-lowering effect of respiratory uncoupling in white fat, we evaluated systemic lipid metabolism in aP2-Ucp1 transgenic mice with ectopic expression of UCP1 in adipose tissue. RESEARCH METHODS AND PROCEDURES Hemizygous and homozygous transgenic mice and their nontransgenic littermates were fed chow or a high-fat diet for up to 3 months. Total TGs, nonesterified fatty acids, and the composition of plasma lipoproteins were analyzed. Hepatic TG production was measured in mice injected with Triton WR1339. Uptake and the use of fatty acids were estimated by measuring adipose tissue lipoprotein lipase activity and fatty acid oxidation, respectively. Adipose tissue gene expression was assessed by quantitative reverse transcriptase-polymerase chain reaction. RESULTS Transgene dosage and the high-fat diet interacted to markedly reduce plasma TGs. This was reflected by decreased concentrations of very-low-density lipoprotein particles in the transgenic mice. Despite normal hepatic TG secretion, the activity of lipoprotein lipase in epididymal fat was enhanced by the high-fat diet in the transgenic mice in a setting of decreased re-esterification and increased in situ fatty acid oxidation. DISCUSSION Respiratory uncoupling in white fat may lower plasma lipids by enhancing their in situ clearance and catabolism.
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Affiliation(s)
- Martin Rossmeisl
- Department of Adipose Tissue Biology, Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic
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Kim SN, Lee W, Bae GU, Kim YK. Anti-diabetic and hypolipidemic effects of Sargassum yezoense in db/db mice. Biochem Biophys Res Commun 2012; 424:675-80. [PMID: 22789850 DOI: 10.1016/j.bbrc.2012.07.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 07/02/2012] [Indexed: 01/05/2023]
Abstract
Peroxisome proliferator-activated receptors (PPARs) have been considered to be desirable targets for metabolic syndrome, even though their specific agonists have several side effects including body weight gain, edema and tissue failure. Previously, we have reported in vitro effects of Sargassum yezoense (SY) and its ingredients, sargaquinoic acid (SQA) and sargahydroquinoic acid (SHQA), on PPARα/γ dual transcriptional activation. In this study, we describe in vivo pharmacological property of SY on metabolic disorders. SY treatment significantly improved glucose and lipid impairment in db/db mice model. More importantly, there are no significant side effects such as body weight gain and hepatomegaly in SY-treated animals, indicating little side effects of SY in liver and lipid metabolism. In addition, SY led to a decrease in the expression of G6Pase for gluconeogenesis in liver responsible for lowering blood glucose level and an increase in the expression of UCP3 in adipose tissue for the reduction of total and LDL-cholesterol level. Altogether, our data suggest that SY would be a potential therapeutic agent against type 2 diabetes and related metabolic disorders by ameliorating the glucose and lipid metabolism.
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Affiliation(s)
- Su-Nam Kim
- Natural Medicine Center, KIST Gangneung Institute, Gangneung 210-340, Republic of Korea.
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Villarroya F, Iglesias R, Giralt M. PPARs in the Control of Uncoupling Proteins Gene Expression. PPAR Res 2011; 2007:74364. [PMID: 17389766 PMCID: PMC1779581 DOI: 10.1155/2007/74364] [Citation(s) in RCA: 145] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Revised: 10/18/2006] [Accepted: 10/18/2006] [Indexed: 11/17/2022] Open
Abstract
Uncoupling proteins (UCPs) are mitochondrial membrane transporters involved in the control of energy conversion in mitochondria. Experimental and genetic evidence relate dysfunctions of UCPs with metabolic syndrome and obesity. The PPAR subtypes mediate to a large extent the transcriptional regulation of the UCP genes, with a distinct relevance depending on the UCP gene and the tissue in which it is expressed. UCP1 gene is under the dual control of PPARγ and PPARα in relation to brown adipocyte differentiation and lipid oxidation, respectively. UCP3 gene is regulated by PPARα and PPARδ in the muscle, heart, and adipose tissues. UCP2 gene is also under the control of PPARs even in tissues in which it is the predominantly expressed UCP (eg, the pancreas and liver). This review summarizes the current understanding of the role of PPARs in UCPs gene expression in normal conditions and also in the context of type-2 diabetes or obesity.
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Affiliation(s)
- Francesc Villarroya
- Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona 585 08007, Spain
- *Francesc Villarroya:
| | - Roser Iglesias
- Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona 585 08007, Spain
| | - Marta Giralt
- Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona 585 08007, Spain
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Effects of Endogenous PPAR Agonist Nitro-Oleic Acid on Metabolic Syndrome in Obese Zucker Rats. PPAR Res 2010; 2010:601562. [PMID: 20671947 PMCID: PMC2910468 DOI: 10.1155/2010/601562] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 04/29/2010] [Accepted: 05/08/2010] [Indexed: 12/22/2022] Open
Abstract
Nitroalkene derivatives of nitro-oleic acid (OA-NO2) are endogenous lipid products with novel signaling properties, particularly the activation of PPARs. The goal of this proposal was to examine the therapeutic potential of this OA-NO2 in treatment of obesity and obesity-related conditions in obese Zucker rats. The animals were randomly divided to receive OA-NO2, oleic acid (OA), both at 7.5 μg/kg/d, or vehicle ethanol via osmotic mini-pumps for 2 weeks. Following OA-NO2 treatment, food intake was decreased as early as the first day and this effect appeared to persist throughout the experimental period. At day 14, body weight gain was significantly reduced by OA-NO2 treatment. This treatment significantly reduced plasma triglyceride and almost normalized plasma free fatty acid and significantly increased plasma high-density lipid (HDL). The plasma TBARS and proteinuria were paralelly decreased. In contrast, none of these parameters were affected by OA treatment. After 14 days of OA-NO2 treatment, hematocrit, a surrogate of fluid retention associated with PPARγ agonists, remained unchanged. Together, these data demonstrated that OA-NO2 may offer an effective and safe therapeutic intervention for obesity and obesity-related conditions.
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García-Rojas P, Antaramian A, González-Dávalos L, Villarroya F, Shimada A, Varela-Echavarría A, Mora O. Induction of peroxisomal proliferator-activated receptor γ and peroxisomal proliferator-activated receptor γ coactivator 1 by unsaturated fatty acids, retinoic acid, and carotenoids in preadipocytes obtained from bovine white adipose tissue1,2. J Anim Sci 2010; 88:1801-8. [DOI: 10.2527/jas.2009-2579] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Bugge A, Siersbaek M, Madsen MS, Göndör A, Rougier C, Mandrup S. A novel intronic peroxisome proliferator-activated receptor gamma enhancer in the uncoupling protein (UCP) 3 gene as a regulator of both UCP2 and -3 expression in adipocytes. J Biol Chem 2010; 285:17310-7. [PMID: 20360005 DOI: 10.1074/jbc.m110.120584] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Uncoupling Proteins (UCPs) are integral ion channels residing in the inner mitochondrial membrane. UCP2 is ubiquitously expressed, while UCP3 is found primarily in muscles and adipose tissue. Although the exact molecular mechanism of action is controversial, it is generally agreed that both homologues function to facilitate mitochondrial fatty acid oxidation. UCP2 and -3 expression is activated by the peroxisome proliferator-activated receptors (PPARs), but so far no PPAR response element has been reported in the vicinity of the Ucp2 and Ucp3 genes. Using genome-wide profiling of PPARgamma occupancy in 3T3-L1 adipocytes we demonstrate that PPARgamma associates with three chromosomal regions in the vicinity of the Ucp3 locus and weakly with a site in intron 1 of the Ucp2 gene. These sites are isolated from the nearest neighboring sites by >900 kb. The most prominent PPARgamma binding site in the Ucp2 and Ucp3 loci is located in intron 1 of the Ucp3 gene and is the only site that facilitates PPARgamma transactivation of a heterologous promoter. This site furthermore transactivates the endogenous Ucp3 promoter, and using chromatin conformation capture we show that it loops out to specifically interact with the Ucp2 promoter and intron 1. Our data indicate that PPARgamma transactivation of both UCP2 and -3 is mediated through this novel enhancer in Ucp3 intron 1.
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Affiliation(s)
- Anne Bugge
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
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Muraoka M, Fukushima A, Viengchareun S, Lombès M, Kishi F, Miyauchi A, Kanematsu M, Doi J, Kajimura J, Nakai R, Uebi T, Okamoto M, Takemori H. Involvement of SIK2/TORC2 signaling cascade in the regulation of insulin-induced PGC-1alpha and UCP-1 gene expression in brown adipocytes. Am J Physiol Endocrinol Metab 2009; 296:E1430-9. [PMID: 19351809 DOI: 10.1152/ajpendo.00024.2009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Salt-inducible kinase 2 (SIK2) is expressed abundantly in adipose tissues and represses cAMP-response element-binding protein (CREB)-mediated gene expression by phosphorylating the coactivator transducer of regulated CREB activity (TORC2). Phosphorylation at Ser(587) of SIK2 diminishes its TORC2 phosphorylation activity. In 3T3-L1 white adipocytes, SIK2 downregulates lipogenic gene in response to nutritional stresses. To investigate the impact of SIK2 on the function of brown adipose tissue (BAT), we used T37i brown adipocytes, mice with diet-induced obesity, and SIK2 mutant (S587A) transgenic mice. When T37i adipocytes were treated with insulin, the levels of peroxisome proliferator-activated receptor-coactivator-1alpha (PGC-1alpha) and uncoupling protein-1 (UCP-1) mRNA were increased, and the induction was inhibited by overexpression of SIK2 (S587A) mutant or dominant-negative CREB. Insulin enhanced SIK2 phosphorylation at Ser(587), which was accompanied by decrease in phospho-TORC2. Similarly, the decrease in the level of SIK2 phosphorylation at Ser(587) was observed in the BAT of mice with diet-induced obesity, which was negatively correlated with TORC2 phosphorylation. To confirm the negative correlation between SIK2 phosphorylation at Ser(587) and TORC2 phosphorylation in BAT, SIK2 mutant (S587A) was overexpressed in adipose tissues by using the adipocyte fatty acid-binding protein 2 promoter. The expression of recombinant SIK2 (S587A) was restricted to BAT, and the levels of phospho-TORC2 were elevated in BAT of transgenic mice. Male transgenic mice developed high-fat diet-induced obesity, and their BAT expressed low levels of PGC-1alpha and UCP-1 mRNA, suggesting that SIK2-TORC2 cascade may be important for the regulation of PGC-1alpha and UCP-1 gene expression in insulin signaling in BAT.
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Affiliation(s)
- Masaaki Muraoka
- Laboratory of Cell Signaling and Metabolism, National Institute of Biomedical Innovation, 7-6-8, Asagi, Saito, Ibaraki, Osaka 567-0085, Japan
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Kim DJ, Oh B, Kim YY. Splicing factor ASF/SF2 and transcription factor PPAR-gamma cooperate to directly regulate transcription of uncoupling protein-3. Biochem Biophys Res Commun 2008; 378:877-82. [PMID: 19073146 DOI: 10.1016/j.bbrc.2008.12.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Accepted: 12/03/2008] [Indexed: 11/30/2022]
Abstract
The different isoforms of the uncoupling protein-3 (UCP3) are expressed in skeletal muscle and are up-regulated by splicing factors. Here, we report that UCP3 alternative splicing (alternative polyadenylation) is regulated by cooperation between the splicing factor ASF/SF2 and the transcription factor PPAR-gamma. We found that ASF/SF2 activates formation of long-form UCP3 (UCP3(L)) by inhibiting a cleavage and polyadenylation signal (AATAAA) located in its final intron that prematurely terminates message elongation. PPAR-gamma activates this process by directly interacting with ASF/SF2, providing the first example of a direct link between a transcription factor and alternative splicing. Activation of ASF/SF2 promotes formation of UCP3(L), whereas loss of ASF/SF2 decreases production of both UCP3(L) and short-form UCP3 (UCP3(S)). We suggest that the relative abundance of ASF/SF2 and PPAR-gamma determines the ratio of UCP3 isoforms.
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Affiliation(s)
- Dong-Joon Kim
- Center for Genome Science, National Institute of Health in Korea, Eunpyung-Gu, Seoul, Republic of Korea
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Nagao K, Yanagita T. Bioactive lipids in metabolic syndrome. Prog Lipid Res 2008; 47:127-46. [DOI: 10.1016/j.plipres.2007.12.002] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Revised: 11/30/2007] [Accepted: 12/05/2007] [Indexed: 02/06/2023]
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Pang J, Choi Y, Park T. Ilex paraguariensis extract ameliorates obesity induced by high-fat diet: potential role of AMPK in the visceral adipose tissue. Arch Biochem Biophys 2008; 476:178-85. [PMID: 18314006 DOI: 10.1016/j.abb.2008.02.019] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Revised: 01/23/2008] [Accepted: 02/19/2008] [Indexed: 10/22/2022]
Abstract
The aim of present study was to investigate the anti-obesity effect of Ilex paraguariensis extract and its molecular mechanism in rats rendered obese by a high-fat diet (HFD). I. paraguariensis extract supplementation significantly lowered body weight, visceral fat-pad weights, blood and hepatic lipid, glucose, insulin, and leptin levels of rats administered HFD. Feeding I. paraguariensis extract reversed the HFD-induced downregulation of the epididymal adipose tissue genes implicated in adipogenesis or thermogenesis, such as peroxisome proliferators' activated receptor gamma2, adipocyte fatty acid binding protein, sterol-regulatory-element-binding protein-1c, fatty acid synthase, HMG-CoA reductase, uncoupling protein 2, and uncoupling protein 3. Dietary supplementation with I. paraguariensis extract protected rats from the HFD-induced decreases in the phospho-AMP-activated protein kinase (AMPK)/AMPK and phospho-acetyl-CoA carboxylase (ACC)/ACC protein ratio related to fatty acid oxidation in the edipidymal adipose tissue. The present study reports that the I. paraguariensis extract can have a protective effect against a HFD-induced obesity in rats through an enhanced expression of uncoupling proteins and elevated AMPK phosphorylation in the visceral adipose tissue.
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Affiliation(s)
- Jisook Pang
- Department of Food and Nutrition, Brain Korea 21 Project, Yonsei University, 134 Shinchon-dong, Sudaemun-ku, Seoul 120-749, South Korea
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Kaput J, Perlina A, Hatipoglu B, Bartholomew A, Nikolsky Y. Nutrigenomics: concepts and applications to pharmacogenomics and clinical medicine. Pharmacogenomics 2007; 8:369-90. [PMID: 17391074 DOI: 10.2217/14622416.8.4.369] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The maintenance of health and the prevention and treatment of chronic diseases are influenced by naturally occurring chemicals in foods. In addition to supplying the substrates for producing energy, a large number of dietary chemicals are bioactive--that is, they alter the regulation of biological processes and, either directly or indirectly, the expression of genetic information. Nutrients and bioactives may produce different physiological phenotypes among individuals because of genetic variability and not only alter health, but also disease initiation, progression and severity. The study and application of gene-nutrient interactions is called nutritional genomics or nutrigenomics. Nutrigenomic concepts, research strategies and clinical implementation are similar to and overlap those of pharmacogenomics, and both are fundamental to the treatment of disease and maintenance of optimal health.
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Affiliation(s)
- Jim Kaput
- Department of Surgery, University of Illinois Chicago, 909 South Wolcott Street MC 958, Chicago, IL 60612, USA.
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Pinaire JA, Reifel-Miller A. Therapeutic potential of retinoid x receptor modulators for the treatment of the metabolic syndrome. PPAR Res 2007; 2007:94156. [PMID: 17497022 PMCID: PMC1852898 DOI: 10.1155/2007/94156] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Revised: 01/04/2007] [Accepted: 01/04/2007] [Indexed: 01/30/2023] Open
Abstract
The increasing prevalence of obesity is a fundamental contributor
to the growing prevalence of the metabolic syndrome. Rexinoids, a
class of compounds that selectively bind and activate RXR,
are being studied as a potential option for the treatment of
metabolic syndrome. These compounds have glucose-lowering,
insulin-sensitizing, and antiobesity effects in animal models
of insulin resistance and type 2 diabetes. However,
undesirable side effects such as hypertriglyceridemia and
suppression of the thyroid hormone axis also occur.
This review examines and compares the effects of four RXR-selective
ligands: LGD1069, LG100268, AGN194204, and LG101506, a selective
RXR modulator. Similar to selective modulators of other nuclear
receptors such as the estrogen receptor (SERMs), LG101506
binding to RXR selectively maintains the desirable characteristic
effects of rexinoids while minimizing the undesirable effects.
These recent findings suggest that, with continued research efforts,
RXR-specific ligands with improved pharmacological profiles may
eventually be available as additional treatment options for the
current epidemic of obesity, insulin resistance, type 2 diabetes,
and all of the associated metabolic sequelae.
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Affiliation(s)
- Jane A. Pinaire
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN 46285, USA
- *Jane A. Pinaire:
| | - Anne Reifel-Miller
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN 46285, USA
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Abstract
Insulin resistance typically reflects multiple defects of insulin receptor and post-receptor signalling that impair a diverse range of metabolic and vascular actions. Many potential intervention targets and compounds with therapeutic activity have been described. Proof of principle for a non-peptide insulin mimetic has been demonstrated by specific activation of the intracellular B-subunit of the insulin receptor. Potentiation of insulin action has been achieved with agents that enhance phosphorylation and prolong the tyrosine kinase activity of the insulin receptor and its protein substrates after activation by insulin. These include inhibitors of phosphatases and serine kinases that normally prevent or terminate tyrosine kinase signalling. Additional approaches involve increasing the activity of phosphatidylinositol 3-kinase and other downstream components of the insulin signalling pathways. Experimental interventions to remove signalling defects caused by cytokines, certain adipocyte hormones, excess fatty acids, glucotoxicity and negative feedback by distal signalling steps have also indicated therapeutic possibilities. Several hormones, metabolic enzymes, minerals, co-factors and transcription co-activators have shown insulin-sensitising potential. Since insulin resistance affects many metabolic and cardiovascular diseases, it provides an opportunity for simultaneous therapeutic attack on a broad front.
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Affiliation(s)
- Clifford J Bailey
- Deabetes Research Group, School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, UK.
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Chapter 5 Metabolic modifiers in animal nutrition: potential benefits and risks. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/s1877-1823(09)70092-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Yu XX, Murray SF, Pandey SK, Booten SL, Bao D, Song XZ, Kelly S, Chen S, McKay R, Monia BP, Bhanot S. Antisense oligonucleotide reduction of DGAT2 expression improves hepatic steatosis and hyperlipidemia in obese mice. Hepatology 2005; 42:362-71. [PMID: 16001399 DOI: 10.1002/hep.20783] [Citation(s) in RCA: 222] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
In this study, we investigated the role of acyl-coenzyme A:diacylglycerol acyltransferase 2 (DGAT2) in glucose and lipid metabolism in obese mice by reducing its expression in liver and fat with an optimized antisense oligonucleotide (ASO). High-fat diet-induced obese (DIO) C57BL/6J mice and ob/ob mice were treated with DGAT2 ASO, control ASO, or saline. DGAT2 ASO treatment reduced DGAT2 messenger RNA (mRNA) levels by more than 75% in both liver and fat but did not change DGAT1 mRNA levels in either of these tissues, which resulted in decreased DGAT activity in liver but not in fat. DGAT2 ASO treatment did not cause significant changes in body weight, adiposity, metabolic rate, insulin sensitivity, or skin microstructure. However, DGAT2 ASO treatment caused a marked reduction in hepatic triglyceride content and improved hepatic steatosis in both models, which was consistent with a dramatic decrease in triglyceride synthesis and an increase in fatty acid oxidation observed in primary mouse hepatocytes treated with DGAT2 ASO. In addition, the treatment lowered hepatic triglyceride secretion rate and plasma triglyceride levels, and improved plasma lipoprotein profile in DIO mice. The positive effects of the DGAT2 ASO were accompanied by a reduction in the mRNA levels of several hepatic lipogenic genes, including SCD1, FAS, ACC1, ACC2, ATP-citrate lyase, glycerol kinase, and HMG-CoA reductase. In conclusion, reduction of DGAT2 expression in obese animals can reduce hepatic lipogenesis and hepatic steatosis as well as attenuate hyperlipidemia, thereby leading to an improvement in metabolic syndrome.
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Affiliation(s)
- Xing Xian Yu
- Department of Antisense Drug Discovery, Isis Pharmaceuticals, Inc., 2292 Faraday Avenue, Carlsbad, CA 92008, USA
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Hong SE, Ahn IS, Jung HS, Rayner DV, Do MS. Effect of retinoic acid on leptin, glycerol, and glucose levels in mature rat adipocytes in vitro. J Med Food 2005; 7:320-6. [PMID: 15383226 DOI: 10.1089/jmf.2004.7.320] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To elucidate the effects of retinoic acids (RAs) on adipogenesis and insulin sensitivity, we treated mature adipocytes with two different kinds of RA, 9-cis-RA and all-trans-RA. Both 9-cis- and all-trans-RA inhibited the secretion of leptin. However, the inhibition was significantly decreased at a higher dose of each RA. The inhibitory effect of 9-cis-RA was synergistically enhanced by the addition of rosiglitazone, a synthetic ligand for peroxisome proliferator-activated receptor (PPAR) gamma. 9-cis-RA also leads to adipogenesis in a dose-dependent manner. On the contrary, all-trans-RA does not increase adipogenesis in a dose-dependent manner. To clarify the antidiabetic effects of RA, glucose uptake was assessed by estimating glucose concentrations in the medium. 9-cis-RA reduced glucose levels in the culture media, but all-trans-RA did not. In conclusion, all-trans-RA does not alter adipogenesis and glucose uptake but does inhibit leptin secretion. 9-cis-RA, however, seems to increase both adipogenesis and glucose uptake through activation of the retinoid X receptor/PPARgamma heterodimer.
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Affiliation(s)
- Seong-Eui Hong
- School of Life and Food Sciences, Handong Global University, Pohang, Kyungbuk, South Korea
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Hammarstedt A, Sopasakis VR, Gogg S, Jansson PA, Smith U. Improved insulin sensitivity and adipose tissue dysregulation after short-term treatment with pioglitazone in non-diabetic, insulin-resistant subjects. Diabetologia 2005; 48:96-104. [PMID: 15624096 DOI: 10.1007/s00125-004-1612-3] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Accepted: 09/14/2004] [Indexed: 10/26/2022]
Abstract
AIMS/HYPOTHESIS We examined whether short-term treatment with a thiazolidinedione improves insulin sensitivity in non-obese but insulin-resistant subjects and whether this is associated with an improvement in dysregulated adipose tissue (reduced expression of IRS-1, GLUT4, PPARgamma co-activator 1 and markers of terminal differentiation) that we have previously documented to be associated with insulin resistance. METHODS Ten non-diabetic subjects, identified as having low IRS-1 and GLUT-4 protein in adipose cells as markers of insulin resistance, underwent 3 weeks of treatment with pioglitazone. The euglycaemic-hyperinsulinaemic clamp technique was used to measure insulin sensitivity before and after treatment. Serum samples were analysed for glucose, insulin, lipids, total and high-molecular-weight (HMW) adiponectin levels. Biopsies from abdominal subcutaneous adipose tissue were taken, cell size measured, mRNA and protein extracted and quantified using real-time RT-PCR and Western blot. RESULTS Insulin sensitivity was improved after 3 weeks treatment and circulating total as well as HMW adiponectin increased in all subjects, while no effect was seen on serum lipids. In the adipose cells, gene and protein expression of IRS-1 and PPARgamma co-activator 1 remained unchanged, while adiponectin, adipocyte P 2, uncoupling protein 2, GLUT4 and liver X receptor-alpha increased. Insulin-stimulated tyrosine phosphorylation and p-ser-PKB/Akt increased, while no significant effect of thiazolidinedione treatment was seen on the inflammatory status of the adipose tissue in these non-obese subjects. CONCLUSIONS/INTERPRETATION Short-term treatment with pioglitazone improved insulin sensitivity in the absence of any changes in circulating NEFA or lipid levels. Several markers of adipose cell differentiation, previously shown to be reduced in insulin resistance, were augmented, supporting the concept that insulin resistance in these individuals is associated with impaired terminal differentiation of the adipose cells.
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Affiliation(s)
- A Hammarstedt
- The Lundberg Laboratory for Diabetes Research, Department of Internal Medicine, The Sahlgrenska Academy at Göteborg University, Göteborg, Sweden
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Gee MK, Zhang L, Rankin SE, Collins JN, Kauffman RF, Wagner JD. Rosiglitazone treatment improves insulin regulation and dyslipidemia in type 2 diabetic cynomolgus monkeys. Metabolism 2004; 53:1121-5. [PMID: 15334371 DOI: 10.1016/j.metabol.2004.03.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Impairment of peroxisome proliferator-activated receptor-gamma (PPAR-gamma), a nuclear receptor that regulates genes involved in lipid and glucose metabolism, may contribute to the onset of metabolic disorders such as diabetes and the accompanying dyslipidemia. Fat-derived tumor necrosis factor alpha (TNF-alpha) and the acute-phase response protein, C-reactive protein (CRP), may also have a role in the development of obesity-related insulin resistance and type 2 diabetes mellitus. In this study, a group of 14 naturally occurring, insulin-requiring, type 2 diabetic cynomolgus monkeys were used to evaluate the effects of the PPAR-gamma agonist, rosiglitazone, on glycemic and lipid parameters and serum levels of TNF-alpha and CRP. The animals were randomized into 2 groups of 7. One group was treated with 0.5 mg/kg rosiglitazone orally once a day for 7 weeks. Blood was collected for evaluation at baseline, at 2 and 7 weeks during the treatment period, and at 7 and 13 weeks after treatment. Daily insulin requirements were recorded during the entire study. Results showed daily exogenous insulin requirements were significantly reduced (P <.01) in those treated with rosiglitazone, while glycemic control was maintained. Plasma triglyceride concentrations were significantly lower (P <.01) whereas plasma cholesterol levels tended to be lower and high-density lipoprotein (HDL) concentrations tended to be higher after treatment. No significant differences were noted in TNF-alpha and CRP serum levels during the treatment period. Body weights remained steady in both groups during the study. These results suggest overall improvement in insulin regulation and lipid profiles during treatment with rosiglitazone.
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Affiliation(s)
- Melaney K Gee
- Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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28
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Abstract
The function of brown adipose tissue is to transfer energy from food into heat; physiologically, both the heat produced and the resulting decrease in metabolic efficiency can be of significance. Both the acute activity of the tissue, i.e., the heat production, and the recruitment process in the tissue (that results in a higher thermogenic capacity) are under the control of norepinephrine released from sympathetic nerves. In thermoregulatory thermogenesis, brown adipose tissue is essential for classical nonshivering thermogenesis (this phenomenon does not exist in the absence of functional brown adipose tissue), as well as for the cold acclimation-recruited norepinephrine-induced thermogenesis. Heat production from brown adipose tissue is activated whenever the organism is in need of extra heat, e.g., postnatally, during entry into a febrile state, and during arousal from hibernation, and the rate of thermogenesis is centrally controlled via a pathway initiated in the hypothalamus. Feeding as such also results in activation of brown adipose tissue; a series of diets, apparently all characterized by being low in protein, result in a leptin-dependent recruitment of the tissue; this metaboloregulatory thermogenesis is also under hypothalamic control. When the tissue is active, high amounts of lipids and glucose are combusted in the tissue. The development of brown adipose tissue with its characteristic protein, uncoupling protein-1 (UCP1), was probably determinative for the evolutionary success of mammals, as its thermogenesis enhances neonatal survival and allows for active life even in cold surroundings.
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Affiliation(s)
- Barbara Cannon
- The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden
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Ogilvie KM, Saladin R, Nagy TR, Urcan MS, Heyman RA, Leibowitz MD. Activation of the retinoid X receptor suppresses appetite in the rat. Endocrinology 2004; 145:565-73. [PMID: 14605005 DOI: 10.1210/en.2003-0907] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The retinoid X receptor (RXR), a ubiquitously expressed intracellular receptor, regulates pathways controlling glucose, triglycerides, cholesterol, and bile acid metabolism. In addition to its role in those metabolic pathways, we reported that RXR activation with a pan agonist [e.g. LG100268 (LG268)] decreases both body weight gain (BWG) and food consumption (FC) in obese, insulin-resistant rodents. In parallel with those changes in energy balance, we show here that activation of RXR pathways results in adipose tissue remodeling, particularly within sc fat where the rate of apoptosis is increased 5-fold. This change may underlie the selective decrease in fat mass observed in Zucker fatty rats treated with LG268 for 6 wk. Because FC is strongly correlated with BWG in treated animals, we hypothesized that regulation of FC might be the primary mechanism underlying reduced BWG during RXR agonist administration. Importantly, decreased FC is due to decreased meal size, suggestive of induced satiety rather than malaise and/or aversion to food. Furthermore, administration of LG268 directly into the brain via intracerebroventricular injection also reduces FC, BWG, and insulin, whereas the elevation in triglycerides observed after oral administration is absent. The latter observation suggests that RXR actions on energy balance and lipid homeostasis are separable. Therefore, ligand-mediated activation of either an RXR homodimer or an unidentified heterodimeric complex regulates pathways controlling energy balance at least in part via a central nervous system-mediated mechanism.
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Affiliation(s)
- Kathleen M Ogilvie
- Department of Pharmacology, Ligand Pharmacruticals Inc., San Diego, CA 92121, USA.
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Giordano A, Calvani M, Petillo O, Carteni' M, Melone MRAB, Peluso G. Skeletal muscle metabolism in physiology and in cancer disease. J Cell Biochem 2003; 90:170-86. [PMID: 12938166 DOI: 10.1002/jcb.10601] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Skeletal muscle is a tissue of high demand and it accounts for most of daily energy consumption. The classical concept of energy metabolism in skeletal muscle has been profoundly modified on the basis of studies showing the influence of additional factors (i.e., uncoupling proteins (UCPs) and peroxisome proliferator activated receptors (PPARs)) controlling parameters, such as substrate availability, cellular enzymes, carrier proteins, and proton leak, able to affect glycolysis, nutrient oxidation, and protein degradation. This extremely balanced system is greatly altered by cancer disease that can induce muscle cachexia with significant deleterious consequences and results in muscle wasting and weakness, delaying or preventing ambulation, and rehabilitation in catabolic patients.
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Affiliation(s)
- Anna Giordano
- Department of Experimental Medicine, II University of Naples, School of Medicine, Naples, Italy
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Larsen PJ, Jensen PB, Sørensen RV, Larsen LK, Vrang N, Wulff EM, Wassermann K. Differential influences of peroxisome proliferator-activated receptors gamma and -alpha on food intake and energy homeostasis. Diabetes 2003; 52:2249-59. [PMID: 12941763 DOI: 10.2337/diabetes.52.9.2249] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Chronic treatment with compounds activating peroxisome proliferator-activated receptor (PPAR)gamma and -alpha influences body energy stores, but the underlying mechanisms are only partially known. In a chronic-dosing study, equiefficacious antihyperglycemic doses of the PPAR gamma agonist pioglitazone and PPAR alpha/gamma dual activator ragaglitazar were administered to obesity-prone male rats. The PPAR alpha agonist fenofibrate had no effect on insulin sensitivity. Pioglitazone transiently increased and fenofibrate transiently decreased food intake, whereas ragaglitazar had no impact on feeding. As a result, body adiposity increased in pioglitazone-treated rats and decreased in fenofibrate-treated rats. PPAR gamma compounds markedly increased feed efficiency, whereas PPAR alpha agonist treatment decreased feed efficiency. In fenofibrate-treated rats, plasma acetoacetate was significantly elevated. Plasma levels of this potentially anorectic ketone body were unaffected in pioglitazone- and ragaglitazar-treated rats. High-fat feeding markedly increased visceral fat pads, and this was prevented by pioglitazone and ragaglitazar treatment. Pioglitazone treatment enlarged subcutaneous adiposity in high-fat-fed rats. In conclusion, PPAR gamma activation increases both food intake and feed efficiency, resulting in net accumulation of subcutaneous body fat. The impact of PPAR gamma activation on feeding and feed efficiency appears to be partially independent because the PPAR alpha component of ragaglitazar completely counteracts the orexigenic actions of PPAR gamma activation without marked impact on feed efficiency.
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Sardana K, Sehgal VN. Retinoids: fascinating up-and-coming scenario. J Dermatol 2003; 30:355-80. [PMID: 12773802 DOI: 10.1111/j.1346-8138.2003.tb00402.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2002] [Accepted: 02/04/2003] [Indexed: 11/28/2022]
Abstract
Retinoids have been in sharp focus ever since their introduction 30 years ago. They include any drug (s) that bind to retinoid receptors and elicit a biological response. Enormous information on the subject seems to embroil the recent literature. Practically it is impossible to clearly comprehend the undercurrents. The meticulously dispensing text envisages surmounting the perspective reader's predicaments. Accordingly, retinoids and their related facets namely retinoid receptors, classification, mode of action, and the pharmacological diversity have been precisely defined. Commonly used systemic retinoids too have been given a substantial fresh look along with their monitoring. Overall, adverse effects and relative and absolute contraindications have been scrupulously incorporated. Human immuno deficiency virus (HIV) and isoretinoid for acne, in particular, have been highlighted. Micronized isotretinoin formulations have also been taken care so also commonly used topical retinoids. Tretinoin and their newer formulation have also been accounted for along with tretinoin polymer cream. Adapalene, a new chemical entity possessing a unique physico-chemical activity similar to that of tretinoin has also been dealt with. Newer retinoids are likely to be a subject of intrigue. A focus on future potentials of retinoids is its special ingredient. The inclusion of details of rexinoid the most recent introduction in their purview is likely to invoke interest to further consolidate its reckoning in future. All in all the text of the paper should provide an insight into the current rumbling around retinoids.
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Affiliation(s)
- Kabir Sardana
- Department of Dermatology and Venereology, Lady Hardinge Medical College, New Delhi, India
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Abstract
Peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor involved in the control of metabolism. Research on PPARgamma is oriented towards understanding its role in insulin sensitization, which was inspired by the discovery that antidiabetic agents, the thiazolidinediones, were agonists for PPARgamma. PPARgamma stimulation improves glucose tolerance and insulin sensitivity in type 2 diabetic patients and in animal models of insulin resistance through mechanisms that are incompletely understood. Upon activation, PPARgamma heterodimerizes with retinoid X receptor, recruits specific cofactors, and binds to responsive DNA elements, thereby stimulating the transcription of target genes. Because PPARgamma is highly enriched in adipose tissue and because of its major role in adipocyte differentiation, it is thought that the effects of PPARgamma in adipose tissue are crucial to explain its role in insulin sensitization, but recent studies have highlighted the contribution of other tissues as well. Although relatively potent for their insulin-sensitizing action, currently marketed PPARgamma activators have some important undesirable side effects. These concerns led to the discovery of new ligands with potent antidiabetic properties but devoid of certain of these side effects. Data from human genetic studies and from PPARgamma heterozygous knockout mice indicate that a reduction in PPARgamma activity could paradoxically improve insulin sensitivity. These findings suggest that modulation of PPARgamma activity by partial agonists or compounds that affect cofactor recruitment might hold promise for the treatment of insulin resistance.
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Affiliation(s)
- Frédéric Picard
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/ULP, B.P. 163, F-67404 Illkirch, C.U. de Strasbourg, France
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Schrauwen P, Hinderling V, Hesselink MKC, Schaart G, Kornips E, Saris WHM, Westerterp-Plantenga M, Langhans W. Etomoxir-induced increase in UCP3 supports a role of uncoupling protein 3 as a mitochondrial fatty acid anion exporter. FASEB J 2002; 16:1688-90. [PMID: 12206997 DOI: 10.1096/fj.02-0275fje] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The physiological function of human uncoupling protein-3 is still unknown. Uncoupling protein-3 is increased during fasting and high-fat feeding. In these situations the availability of fatty acids to the mitochondria exceeds the capacity to metabolize fatty acids, suggesting a role for uncoupling protein-3 in handling of non-metabolizable fatty acids. To test the hypothesis that uncoupling protein-3 acts as a mitochondrial exporter of non-metabolizable fatty acids from the mitochondrial matrix, we gave human subjects Etomoxir (which blocks mitochondrial entry of fatty acids) or placebo in a cross-over design during a 36-h stay in a respiration chamber. Etomoxir inhibited 24-h fat oxidation and fat oxidation during exercise by approximately 14-19%. Surprisingly, uncoupling protein-3 content in human vastus lateralis muscle was markedly up-regulated within 36 h of Etomoxir administration. Up-regulation of uncoupling protein-3 was accompanied by lowered fasting blood glucose and increased translocation of glucose transporter-4. These data support the hypothesis that the physiological function of uncoupling protein-3 is to facilitate the outward transport of non-metabolizable fatty acids from the mitochondrial matrix and thus prevents mitochondria from the potential deleterious effects of high fatty acid levels. In addition our data show that up-regulation of uncoupling protein-3 can be beneficial in the treatment of type 2 diabetes.
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Affiliation(s)
- Patrick Schrauwen
- Nutrition and Toxicology Research Institute Maastricht, Department of Human Biology, Maastricht University, 6200 MD Maastricht, The Netherlands.
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35
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Abstract
SUMMARY
The uncoupling protein-1 (UCP1) homologues UCP2 and UCP3 are able to uncouple ATP production from mitochondrial respiration, thereby dissipating energy as heat and affecting energy metabolism efficiency. In contrast to UCP1, which plays an important role in adaptive thermogenesis, UCP2 and UCP3 do not have a primary role in the regulation of energy metabolism. UCP2, which is expressed in a wide variety of tissues, including white adipose tissue,skeletal muscle and tissues of the immune system, has been suggested to affect the production of reactive oxygen species. UCP2 has also been suggested to regulate the [ATP]/[ADP] ratio and was recently shown to influence insulin secretion in the β-cells of the pancreas. UCP3, in contrast, is expressed predominantly in skeletal muscle and has been associated with whole-body energy metabolism. However, the primary function of UCP3 is not the regulation of energy metabolism. For example, fasting, a condition attenuating energy expenditure, upregulates UCP3 expression. Moreover, UCP3-knockout mice have a normal metabolic rate. The exact function of UCP3 therefore remains to be elucidated, but putative roles for UCP3 include involvement in the regulation of ROS, in mitochondrial fatty acid transport and in the regulation of glucose metabolism in skeletal muscle. Whatever the primary function of these novel uncoupling proteins, a secondary effect via uncoupling might allow them to influence (but not to regulate) energy metabolism, which would be consistent with the observations from linkage and association studies. Therefore, UCP2 and UCP3 remain interesting targets for pharmacological upregulation in the treatment of obesity and diabetes.
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Affiliation(s)
- Patrick Schrauwen
- Nutrition and Toxicology Research Institute Maastricht (NUTRIM) Department of Human Biology, Maastricht University, The Netherlands.
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Wang S, Cawthorne MA, Clapham JC. Enhanced diabetogenic effect of streptozotocin in mice overexpressing UCP-3 in skeletal muscle. Ann N Y Acad Sci 2002; 967:112-9. [PMID: 12079841 DOI: 10.1111/j.1749-6632.2002.tb04269.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Diabetic patients exhibit varying degrees of increased muscle UCP-3 expression in skeletal muscle and, in rodents, the pancreatoxin streptozotocin (STZ) upregulates UCP-3 mRNA in skeletal and cardiac muscles. We have investigated the development of STZ-induced diabetes in transgenic mice overexpressing UCP-3 in skeletal muscle in order to provide further insight on the functional role of muscle UCP-3. UCP-3 transgenic mice treated with STZ (UCP3-STZ) showed a significant increase in blood glucose concentration 3 days after the last dose of STZ with a progressive induction of diabetes, attaining blood glucose concentrations of 24.7 +/- 1.5 mmol/L on day 17. Wild-type mice treated with STZ (WT-STZ) only started to show an increase in blood glucose concentration 6 days after the last dose of STZ and peaked on day 17 at a lower concentration than in the UCP-STZ mice. The pancreatic insulin content of UCP-3 control mice (UCP3-CON) was decreased relative to wild-type control mice (WT-CON), and STZ reduced the total pancreatic insulin content by 72% in WT-STZ mice and by 88% in UCP3-STZ mice. In an insulin tolerance test, blood glucose concentrations declined more in the UCP-3 transgenic mice than in the wild-type mice. Mice overexpressing UCP-3 in skeletal muscle have a lower pancreatic insulin content, but tend to be more insulin-sensitive. These twin actions result in an increased susceptibility to STZ-induced diabetes in UCP-3 transgenic mice.
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Affiliation(s)
- Steven Wang
- Clore Laboratory, University of Buckingham, United Kingdom.
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Schrauwen P, Hesselink MK, Blaak EE, Borghouts LB, Schaart G, Saris WH, Keizer HA. Uncoupling protein 3 content is decreased in skeletal muscle of patients with type 2 diabetes. Diabetes 2001; 50:2870-3. [PMID: 11723073 DOI: 10.2337/diabetes.50.12.2870] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Recently, a role for uncoupling protein-3 (UCP3) in carbohydrate metabolism and in type 2 diabetes has been suggested. Mice overexpressing UCP3 in skeletal muscle showed reduced fasting plasma glucose levels, improved glucose tolerance after an oral glucose load, and reduced fasting plasma insulin levels. However, data regarding the expression of UCP3 in patients with type 2 diabetes is inconsistent, and so far, there have been no reports of UCP3 protein content. Here we compared, for the first time, the protein levels of UCP3 in vastus lateralis muscle in 14 male type 2 diabetic patients (age 49.8 +/- 2.1 years; BMI 27.2 +/- 1.2 kg/m(2); mean +/- SE) with 16 male control subjects (age 48.0 +/- 1.9 years; BMI 23.4 +/- 0.6 kg/m(2)). We found that UCP3 protein levels were twice as low in patients with type 2 diabetes compared with control subjects (117 +/- 16 vs. 58 +/- 12 AU; P = 0.007). There was no correlation between UCP3 content and BMI. In conclusion, UCP3 content is lower in type 2 diabetic patients compared with healthy control subjects. These results are consistent with a role for UCP3 in glucose homeostasis and suggest a role for UCP3 in type 2 diabetes.
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Affiliation(s)
- P Schrauwen
- Department of Human Biology, Maastricht University, Maastricht, the Netherlands.
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Schrauwen P, Saris WH, Hesselink MK. An alternative function for human uncoupling protein 3: protection of mitochondria against accumulation of nonesterified fatty acids inside the mitochondrial matrix. FASEB J 2001; 15:2497-502. [PMID: 11689475 DOI: 10.1096/fj.01-0400hyp] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The physiological function of the human uncoupling protein 3 UCP3, which was discovered in 1997, is unknown. Here we evaluate the available data on human UCP3 expression and show that UCP3 is up-regulated in situations where fatty acid delivery to the mitochondria exceeds oxidative capacity, whereas down-regulation of UCP3 is observed when oxidative capacity is enhanced. With a surplus of fatty acid delivery, accumulation of nonesterified fatty acids in the cytoplasm is likely to occur. Although the inner mitochondrial membrane provides a barrier for nonesterified fatty acids, neutral nonesterified fatty acids can partition into the phospholipid bilayer and flip-flop to the other side of the membrane, where they can be released into the mitochondrial matrix. Due to pH differences, these nonesterified fatty acids will be protonated. Because fatty acid anions can neither be metabolized inside the matrix or cross the inner mitochondrial membrane, accumulation of nonesterified fatty acids inside the matrix might occur. Therefore, we postulate that UCP3 is required for the outward translocation of fatty acids from the mitochondrial matrix. In this way, UCP3 is involved in the protection of mitochondria against accumulation of nonesterified fatty acids inside the mitochondrial matrix.
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Affiliation(s)
- P Schrauwen
- Department of Human Biology, Maastricht University, The Netherlands.
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39
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Abstract
New agents are being developed to address the underlying endocrinopathies and metabolic disturbances of type 2 diabetes. Stimulants of the nuclear peroxisome proliferator-activated receptor gamma (PPAR gamma) are being identified to selectively improve insulin actions, and dual agonists of PPAR gamma and PPAR alpha are being evaluated for enhanced control of hyperglycemia and dyslipidemia. Novel activators of insulin receptor phosphorylation and inhibitors of receptor dephosphorylation are offering encouraging leads for new agents. Analogues of glucagon-like peptide-1 that increase glucose-induced insulin secretion may additionally increase beta-cell neogenesis from progenitor duct cells. The amylin analogue pramlintide, which suppresses glucagon secretion and reduces weight, is advancing in clinical trial. Direct stimulants of glucose utilization and partial inhibitors of gluconeogenesis are providing useful new drug templates. Thus, new pharmacologic approaches are emerging to treat the multiple lesions of type 2 diabetes.
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Affiliation(s)
- C J Bailey
- Department of Pharmaceutical Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
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