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Qin B, Qincao L, He S, Liao Y, Shi J, Xie F, Diao N, Bai L. Parathyroid hormone-related protein prevents high-fat-diet-induced obesity, hepatic steatosis and insulin resistance in mice. Endocr J 2022; 69:55-65. [PMID: 34408100 DOI: 10.1507/endocrj.ej20-0728] [Citation(s) in RCA: 1] [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: 11/23/2022] Open
Abstract
Obesity, closely related to systematic metabolic disorders, has become a major public health problem in recent decades. Here, we aimed to study the function of Parathyroid hormone-related protein (PTHrP) on high fat diet (HFD) induced murine obesity. Male C57BL/6J mice were transduced with adeno-associated virus vector encoding PTHrP (AAV-PTHrP) or adeno-associated virus control vector (AAV-Vehicle), following with HFD for 8 weeks. In addition, mice without transduction were fed on normal diet or HFD, respectively. Histological, metabolic and biochemical changes were detected. At the endpoint of experiment, body weight of mice treated with AAV-PTHrP did not increase as much as mice with AAV-Vehicle, but similar as mice with normal diet. Food efficiency ratio and weight of interscapular brown adipose tissue and epididymal white adipose tissue in mice overexpressed PTHrP were also lower than mice transducted with AAV-Vehicle. Besides, administration of AAV-PTHrP inhibited HFD-induced adipocyte hypertrophy. Protein level of PKA signaling pathway and thermogenic gene in adipose tissue exhibited a significant raise in HFD + AAV-PTHrP group, whereas transcription of inflammatory gene were decreased. Additionally, PTHrP overexpression ameliorated HFD-induced dyslipidemia, hepatic steatosis and insulin sensitivity. In HFD-induced murine obesity model, PTHrP is crucial to maintain metabolic homeostasis. PTHrP drives white adipose tissue browning and inhibits whitening of brown adipose tissue. Most importantly, PTHrP prevented HFD-induced obesity, hepatic steatosis and insulin resistance.
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Affiliation(s)
- Biyan Qin
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Litao Qincao
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Shuying He
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Yan Liao
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Jie Shi
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Fang Xie
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Na Diao
- Guangdong Provincial Key Laboratory of Colorectal Diseases, Department of Gastroenterology, the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510655, China
| | - Lan Bai
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, China
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Vrbacký M, Kovalčíková J, Chawengsaksophak K, Beck IM, Mráček T, Nůsková H, Sedmera D, Papoušek F, Kolář F, Sobol M, Hozák P, Sedlacek R, Houštěk J. Knockout of Tmem70 alters biogenesis of ATP synthase and leads to embryonal lethality in mice. Hum Mol Genet 2018; 25:4674-4685. [PMID: 28173120 DOI: 10.1093/hmg/ddw295] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/22/2016] [Accepted: 08/23/2016] [Indexed: 12/24/2022] Open
Abstract
TMEM70, a 21-kDa protein localized in the inner mitochondrial membrane, has been shown to facilitate the biogenesis of mammalian F1Fo ATP synthase. Mutations of the TMEM70 gene represent the most frequent cause of isolated ATP synthase deficiency resulting in a severe mitochondrial disease presenting as neonatal encephalo-cardiomyopathy (OMIM 604273). To better understand the biological role of this factor, we generated Tmem70-deficient mice and found that the homozygous Tmem70-/- knockouts exhibited profound growth retardation and embryonic lethality at ∼9.5 days post coitum. Blue-Native electrophoresis demonstrated an isolated deficiency in fully assembled ATP synthase in the Tmem70-/- embryos (80% decrease) and a marked accumulation of F1 complexes indicative of impairment in ATP synthase biogenesis that was stalled at the early stage, following the formation of F1 oligomer. Consequently, a decrease in ADP-stimulated State 3 respiration, respiratory control ratio and ATP/ADP ratios, indicated compromised mitochondrial ATP production. Tmem70-/- embryos exhibited delayed development of the cardiovascular system and a disturbed heart mitochondrial ultrastructure, with concentric or irregular cristae structures. Tmem70+/- heterozygous mice were fully viable and displayed normal postnatal growth and development of the mitochondrial oxidative phosphorylation system. Nevertheless, they presented with mild deterioration of heart function. Our results demonstrated that Tmem70 knockout in the mouse results in embryonic lethality due to the lack of ATP synthase and impairment of mitochondrial energy provision. This is analogous to TMEM70 dysfunction in humans and verifies the crucial role of this factor in the biosynthesis and assembly of mammalian ATP synthase.
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Affiliation(s)
- Marek Vrbacký
- Department of Bioenergetics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jana Kovalčíková
- Department of Bioenergetics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.,First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Kallayanee Chawengsaksophak
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic.,Laboratory of Transgenic Models of Diseases, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Inken M Beck
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Tomáš Mráček
- Department of Bioenergetics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Hana Nůsková
- Department of Bioenergetics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - David Sedmera
- Department of Cardiovascular Morphogenesis, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic,Institute of Anatomy, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - František Papoušek
- Department of Developmental Cardiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - František Kolář
- Department of Developmental Cardiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Margarita Sobol
- Laboratory of Biology of the Cell Nucleus, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Pavel Hozák
- Laboratory of Biology of the Cell Nucleus, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Radislav Sedlacek
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic.,Laboratory of Transgenic Models of Diseases, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Josef Houštěk
- Department of Bioenergetics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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Bond LM, Ntambi JM. UCP1 deficiency increases adipose tissue monounsaturated fatty acid synthesis and trafficking to the liver. J Lipid Res 2017; 59:224-236. [PMID: 29203476 DOI: 10.1194/jlr.m078469] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 11/28/2017] [Indexed: 12/26/2022] Open
Abstract
Uncoupling protein-1 (UCP1) facilitates thermogenesis in brown and beige adipocytes and can promote energy expenditure by decreasing mitochondrial respiratory efficiency. Defects in UCP1 and brown adipose tissue thermogenesis subject animals to chronic cold stress and elicit compensatory responses to generate heat. How UCP1 regulates white adipose tissue (WAT) lipid biology and tissue crosstalk is not completely understood. Here, we probed the effect of UCP1 deficiency on FA metabolism in inguinal and epididymal WAT and investigated how these metabolic perturbations influence hepatic lipid homeostasis. We report that at standard housing temperature (21°C), loss of UCP1 induces inguinal WAT de novo lipogenesis through transcriptional activation of the lipogenic gene program and elevated GLUT4. Inguinal adipocyte hyperplasia and depot expansion accompany the increase in lipid synthesis. We also found that UCP1 deficiency elevates adipose stearoyl-CoA desaturase gene expression, and increased inguinal WAT lipolysis supports the transport of adipose-derived palmitoleate (16:1n7) to the liver and hepatic triglyceride accumulation. The observed WAT and liver phenotypes were resolved by housing animals at thermoneutral housing (30°C). These data illustrate depot-specific responses to impaired BAT thermogenesis and communication between WAT and liver in UCP1-/- mice.
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Affiliation(s)
- Laura M Bond
- Departments of Biochemistry University of Wisconsin-Madison, Madison, WI 53706
| | - James M Ntambi
- Departments of Biochemistry University of Wisconsin-Madison, Madison, WI 53706 .,Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706
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Ost M, Keipert S, Klaus S. Targeted mitochondrial uncoupling beyond UCP1 – The fine line between death and metabolic health. Biochimie 2017; 134:77-85. [DOI: 10.1016/j.biochi.2016.11.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 11/07/2016] [Accepted: 11/13/2016] [Indexed: 12/25/2022]
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Houštěk J, Vrbacký M, Hejzlarová K, Zídek V, Landa V, Šilhavý J, Šimáková M, Mlejnek P, Kazdová L, Mikšík I, Neckář J, Papoušek F, Kolář F, Kurtz TW, Pravenec M. Effects of mtDNA in SHR-mtF344 versus SHR conplastic strains on reduced OXPHOS enzyme levels, insulin resistance, cardiac hypertrophy, and systolic dysfunction. Physiol Genomics 2014; 46:671-8. [PMID: 25073601 DOI: 10.1152/physiolgenomics.00069.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Common inbred strains of the laboratory rat can be divided into four major mitochondrial DNA (mtDNA) haplotype groups represented by the BN, F344, LEW, and SHR strains. In the current study, we investigated the metabolic and hemodynamic effects of the SHR vs. F344 mtDNA by comparing the SHR vs. SHR-mt(F344) conplastic strains that are genetically identical except for their mitochondrial genomes. Altogether 13 amino acid substitutions in protein coding genes, seven single nucleotide polymorphisms in tRNA genes, and 12 single nucleotide changes in rRNA genes were detected in F344 mtDNA compared with SHR mtDNA. Analysis of oxidative phosphorylation system (OXPHOS) in heart left ventricles (LV), muscle, and liver revealed reduced activity and content of several respiratory chain complexes in SHR-mt(F344) conplastic rats compared with the SHR strain. Lower function of OXPHOS in LV of conplastic rats was associated with significantly increased relative ventricular mass and reduced fractional shortening that was independent of blood pressure. In addition, conplastic rats exhibited reduced sensitivity of skeletal muscles to insulin action and impaired glucose tolerance. These results provide evidence that inherited alterations in mitochondrial genome, in the absence of variation in the nuclear genome and other confounding factors, predispose to insulin resistance, cardiac hypertrophy and systolic dysfunction.
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Affiliation(s)
- Josef Houštěk
- Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Marek Vrbacký
- Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Kateřina Hejzlarová
- Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Václav Zídek
- Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Vladimír Landa
- Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jan Šilhavý
- Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Miroslava Šimáková
- Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Petr Mlejnek
- Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Ludmila Kazdová
- Institute for Clinical and Experimental Medicine, Prague, Czech Republic; and
| | - Ivan Mikšík
- Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jan Neckář
- Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - František Papoušek
- Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - František Kolář
- Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Theodore W Kurtz
- Department of Laboratory Medicine, University of California, San Francisco, California
| | - Michal Pravenec
- Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic;
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Wang F, Wu M, Liu W, Shen Q, Sun H, Chen S. Expression, purification, and lipolytic activity of recombinant human serum albumin fusion proteins with one domain of human growth hormone inPichia pastoris. Biotechnol Appl Biochem 2013; 60:405-11. [DOI: 10.1002/bab.1108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 02/07/2013] [Indexed: 01/27/2023]
Affiliation(s)
| | - Min Wu
- Institute of Pharmacology & Toxicology and Biochemical Pharmaceutics; College of Pharmaceutical Sciences; Zhejiang University; Hangzhou; People's Republic of China
| | - Wenhui Liu
- Institute of Pharmacology & Toxicology and Biochemical Pharmaceutics; College of Pharmaceutical Sciences; Zhejiang University; Hangzhou; People's Republic of China
| | - Qi Shen
- Institute of Pharmacology & Toxicology and Biochemical Pharmaceutics; College of Pharmaceutical Sciences; Zhejiang University; Hangzhou; People's Republic of China
| | - Hongying Sun
- Institute of Pharmacology & Toxicology and Biochemical Pharmaceutics; College of Pharmaceutical Sciences; Zhejiang University; Hangzhou; People's Republic of China
| | - Shuqing Chen
- Institute of Pharmacology & Toxicology and Biochemical Pharmaceutics; College of Pharmaceutical Sciences; Zhejiang University; Hangzhou; People's Republic of China
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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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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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Houštek J, Hejzlarová K, Vrbacký M, Drahota Z, Landa V, Zídek V, Mlejnek P, Šimáková M, Šilhavy J, Mikšík I, Kazdová L, Oliyarnyk O, Kurtz T, Pravenec M. Nonsynonymous variants in mt-Nd2, mt-Nd4, and mt-Nd5 are linked to effects on oxidative phosphorylation and insulin sensitivity in rat conplastic strains. Physiol Genomics 2012; 44:487-94. [PMID: 22414913 DOI: 10.1152/physiolgenomics.00156.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Common inbred strains of the laboratory rat can be divided into four different mitochondrial DNA haplotype groups represented by the SHR, BN, LEW, and F344 strains. In the current study, we investigated the metabolic and hemodynamic effects of the SHR vs. LEW mitochondrial genomes by comparing the SHR to a new SHR conplastic strain, SHR-mt(LEW); these strains are genetically identical except for their mitochondrial genomes. Complete mitochondrial DNA (mtDNA) sequence analysis comparing the SHR and LEW strains revealed gene variants encoding amino acid substitutions limited to a single mitochondrial enzyme complex, NADH dehydrogenase (complex I), affecting subunits 2, 4, and 5. Two of the variants in the mt-Nd4 subunit gene are located close to variants known to be associated with exercise intolerance and diabetes mellitus in humans. No variants were found in tRNA or rRNA genes. These variants in mt-Nd2, mt-Nd4, and mt-Nd5 in the SHR-mt(LEW) conplastic strain were linked to reductions in oxidative and nonoxidative glucose metabolism in skeletal muscle. In addition, SHR-mt(LEW) conplastic rats showed increased serum nonesterified fatty acid levels and resistance to insulin stimulated incorporation of glucose into adipose tissue lipids. These results provide evidence that inherited variation in mitochondrial genes encoding respiratory chain complex I subunits, in the absence of variation in the nuclear genome and other confounding factors, can influence glucose and lipid metabolism when expressed on the nuclear genetic background of the SHR strain.
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Affiliation(s)
- Josef Houštek
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Teng YW, Ellis JM, Coleman RA, Zeisel SH. Mouse betaine-homocysteine S-methyltransferase deficiency reduces body fat via increasing energy expenditure and impairing lipid synthesis and enhancing glucose oxidation in white adipose tissue. J Biol Chem 2012; 287:16187-98. [PMID: 22362777 DOI: 10.1074/jbc.m111.303255] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Betaine-homocysteine S-methyltransferase (BHMT) catalyzes the synthesis of methionine from homocysteine. In our initial report, we observed a reduced body weight in Bhmt(-/-) mice. We initiated this study to investigate the potential role of BHMT in energy metabolism. Compared with the controls (Bhmt(+/+)), Bhmt(-/-) mice had less fat mass, smaller adipocytes, and better glucose and insulin sensitivities. Compared with the controls, Bhmt(-/-) mice had increased energy expenditure, with no changes in food intake, fat uptake or absorption, or in locomotor activity. The reduced adiposity in Bhmt(-/-) mice was not due to hyperthermogenesis. Bhmt(-/-) mice failed to maintain a normal body temperature upon cold exposure because of limited fuel supplies. In vivo and ex vivo tests showed that Bhmt(-/-) mice had normal lipolytic function. The rate of (14)C-labeled fatty acid incorporated into [(14)C]triacylglycerol was the same in Bhmt(+/+) and Bhmt(-/-) gonadal fat depots (GWAT), but it was 62% lower in Bhmt(-/-) inguinal fat depots (IWAT) compared with that of Bhmt(+/+) mice. The rate of (14)C-labeled fatty acid oxidation was the same in both GWAT and IWAT from Bhmt(+/+) and Bhmt(-/-) mice. At basal level, Bhmt(-/-) GWAT had the same [(14)C]glucose oxidation as did the controls. When stimulated with insulin, Bhmt(-/-) GWAT oxidized 2.4-fold more glucose than did the controls. Compared with the controls, the rate of [(14)C]glucose oxidation was 2.4- and 1.8-fold higher, respectively, in Bhmt(-/-) IWAT without or with insulin stimulus. Our results show for the first time a role for BHMT in energy homeostasis.
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Affiliation(s)
- Ya-Wen Teng
- Department of Nutrition, School of Public Health, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Klaus S, Keipert S, Rossmeisl M, Kopecky J. Augmenting energy expenditure by mitochondrial uncoupling: a role of AMP-activated protein kinase. GENES AND NUTRITION 2011; 7:369-86. [PMID: 22139637 DOI: 10.1007/s12263-011-0260-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 11/18/2011] [Indexed: 11/28/2022]
Abstract
Strategies to prevent and treat obesity aim to decrease energy intake and/or increase energy expenditure. Regarding the increase of energy expenditure, two key intracellular targets may be considered (1) mitochondrial oxidative phosphorylation, the major site of ATP production, and (2) AMP-activated protein kinase (AMPK), the master regulator of cellular energy homeostasis. Experiments performed mainly in transgenic mice revealed a possibility to ameliorate obesity and associated disorders by mitochondrial uncoupling in metabolically relevant tissues, especially in white adipose tissue (WAT), skeletal muscle (SM), and liver. Thus, ectopic expression of brown fat-specific mitochondrial uncoupling protein 1 (UCP1) elicited major metabolic effects both at the cellular/tissue level and at the whole-body level. In addition to expected increases in energy expenditure, surprisingly complex phenotypic effects were detected. The consequences of mitochondrial uncoupling in WAT and SM are not identical, showing robust and stable obesity resistance accompanied by improvement of lipid metabolism in the case of ectopic UCP1 in WAT, while preservation of insulin sensitivity in the context of high-fat feeding represents the major outcome of muscle UCP1 expression. These complex responses could be largely explained by tissue-specific activation of AMPK, triggered by a depression of cellular energy charge. Experimental data support the idea that (1) while being always activated in response to mitochondrial uncoupling and compromised intracellular energy status in general, AMPK could augment energy expenditure and mediate local as well as whole-body effects; and (2) activation of AMPK alone does not lead to induction of energy expenditure and weight reduction.
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Affiliation(s)
- Susanne Klaus
- German Institute of Human Nutrition, Arthur-Scheunert-Allee 114-116, 14558, Nuthetal, Germany
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12
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Cellular and molecular effects of n-3 polyunsaturated fatty acids on adipose tissue biology and metabolism. Clin Sci (Lond) 2009; 116:1-16. [PMID: 19037880 DOI: 10.1042/cs20070456] [Citation(s) in RCA: 200] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Adipose tissue and its secreted products, adipokines, have a major role in the development of obesity-associated metabolic derangements including Type 2 diabetes. Conversely, obesity and its metabolic sequelae may be counteracted by modulating metabolism and secretory functions of adipose tissue. LC-PUFAs (long-chain polyunsaturated fatty acids) of the n-3 series, namely DHA (docosahexaenoic acid; C(22:6n-3)) and EPA (eicosapentaenoic acid; C(20:5n-3)), exert numerous beneficial effects, such as improvements in lipid metabolism and prevention of obesity and diabetes, which partially result from the metabolic action of n-3 LC-PUFAs in adipose tissue. Recent studies highlight the importance of mitochondria in adipose tissue for the maintenance of systemic insulin sensitivity. For instance, both n-3 LC-PUFAs and the antidiabetic drugs TZDs (thiazolidinediones) induce mitochondrial biogenesis and beta-oxidation. The activation of this 'metabolic switch' in adipocytes leads to a decrease in adiposity. Both n-3 LC-PUFAs and TZDs ameliorate a low-grade inflammation of adipose tissue associated with obesity and induce changes in the pattern of secreted adipokines, resulting in improved systemic insulin sensitivity. In contrast with TZDs, which act as agonists of PPARgamma (peroxisome-proliferator-activated receptor-gamma) and promote differentiation of adipocytes and adipose tissue growth, n-3 LC-PUFAs affect fat cells by different mechanisms, including the transcription factors PPARalpha and PPARdelta. Some of the effects of n-3 LC-PUFAs on adipose tissue depend on their active metabolites, especially eicosanoids. Thus treatments affecting adipose tissue by multiple mechanisms, such as combining n-3 LC-PUFAs with either caloric restriction or antidiabetic/anti-obesity drugs, should be explored.
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Neschen S, Katterle Y, Richter J, Augustin R, Scherneck S, Mirhashemi F, Schürmann A, Joost HG, Klaus S. Uncoupling protein 1 expression in murine skeletal muscle increases AMPK activation, glucose turnover, and insulin sensitivity in vivo. Physiol Genomics 2008; 33:333-40. [DOI: 10.1152/physiolgenomics.00226.2007] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Uncoupling of oxidative phosphorylation represents a potential target for the treatment of hyperglycemia and insulin resistance in obesity and type 2 diabetes. The present study investigated whether the expression of uncoupling protein 1 in skeletal muscles of transgenic (mUCP1 TG) mice modulates insulin action in major insulin target tissues in vivo. Euglycemic-hyperinsulinemic clamps (17 pM·kg lean body mass−1·min−1) were performed in 9-mo-old hemizygous male mUCP1 TG mice and wild-type (WT) littermates matched for body composition. mUCP1 TG mice exhibited fasting hypoglycemia and hypoinsulinemia compared with WT mice, whereas fasting hepatic glucose production rates were comparable in both genotypes. mUCP1 TG mice were markedly more sensitive to insulin action compared with WT mice and displayed threefold higher glucose infusion rates, enhanced skeletal muscle and white adipose tissue glucose uptake, and whole body glycolysis rates. In the absence of alterations in plasma adiponectin concentrations, acceleration of insulin-stimulated glucose turnover in skeletal muscle of mUCP1 TG mice was accompanied by increased phosphorylated Akt-to-Akt and phosphorylated AMP-activated protein kinase (AMPK)-to-AMPK ratios compared with WT mice. UCP1-mediated uncoupling of oxidative phosphorylation in skeletal muscle was paralleled by AMPK activation and thereby stimulated insulin-mediated glucose uptake in skeletal muscle.
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Affiliation(s)
- Susanne Neschen
- Department of Pharmacology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
| | - Yvonne Katterle
- Department of Pharmacology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
| | - Julia Richter
- Department of Pharmacology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
| | - Robert Augustin
- Department of Pharmacology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
| | - Stephan Scherneck
- Department of Pharmacology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
| | - Farshad Mirhashemi
- Department of Pharmacology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
| | - Annette Schürmann
- Department of Pharmacology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
| | - Hans-Georg Joost
- Department of Pharmacology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
| | - Susanne Klaus
- Department of Pharmacology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
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Pravenec M, Hyakukoku M, Houstek J, Zidek V, Landa V, Mlejnek P, Miksik I, Dudová-Mothejzikova K, Pecina P, Vrbacký M, Drahota Z, Vojtiskova A, Mracek T, Kazdova L, Oliyarnyk O, Wang J, Ho C, Qi N, Sugimoto K, Kurtz T. Direct linkage of mitochondrial genome variation to risk factors for type 2 diabetes in conplastic strains. Genome Res 2007; 17:1319-26. [PMID: 17693571 PMCID: PMC1950900 DOI: 10.1101/gr.6548207] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Recently, the relationship of mitochondrial DNA (mtDNA) variants to metabolic risk factors for diabetes and other common diseases has begun to attract increasing attention. However, progress in this area has been limited because (1) the phenotypic effects of variation in the mitochondrial genome are difficult to isolate owing to confounding variation in the nuclear genome, imprinting phenomena, and environmental factors; and (2) few animal models have been available for directly investigating the effects of mtDNA variants on complex metabolic phenotypes in vivo. Substitution of different mitochondrial genomes on the same nuclear genetic background in conplastic strains provides a way to unambiguously isolate effects of the mitochondrial genome on complex traits. Here we show that conplastic strains of rats with identical nuclear genomes but divergent mitochondrial genomes that encode amino acid differences in proteins of oxidative phosphorylation exhibit differences in major metabolic risk factors for type 2 diabetes. These results (1) provide the first direct evidence linking naturally occurring variation in the mitochondrial genome, independent of variation in the nuclear genome and other confounding factors, to inherited variation in known risk factors for type 2 diabetes; and (2) establish that spontaneous variation in the mitochondrial genome per se can promote systemic metabolic disturbances relevant to the pathogenesis of common diseases.
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Affiliation(s)
- Michal Pravenec
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Masaya Hyakukoku
- Second Department of Medicine, Sapporo Medical University, Sapporo 060-8543, Japan
- Department of Laboratory Medicine, University of California, San Francisco, California 94107, USA
| | - Josef Houstek
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Vaclav Zidek
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Vladimir Landa
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Petr Mlejnek
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Ivan Miksik
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | | | - Petr Pecina
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Marek Vrbacký
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Zdenek Drahota
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Alena Vojtiskova
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Tomas Mracek
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Ludmila Kazdova
- Institute for Clinical and Experimental Medicine, Prague 140 21, Czech Republic
| | - Olena Oliyarnyk
- Institute for Clinical and Experimental Medicine, Prague 140 21, Czech Republic
| | - Jiaming Wang
- Department of Laboratory Medicine, University of California, San Francisco, California 94107, USA
| | - Christopher Ho
- Department of Laboratory Medicine, University of California, San Francisco, California 94107, USA
| | - Nathan Qi
- Department of Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - Ken Sugimoto
- Department of Geriatric Medicine, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Theodore Kurtz
- Department of Laboratory Medicine, University of California, San Francisco, California 94107, USA
- Corresponding author.E-mail ; fax (801) 912-3103
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15
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Sponarova J, Mustard KJ, Horakova O, Flachs P, Rossmeisl M, Brauner P, Bardova K, Thomason-Hughes M, Braunerova R, Janovska P, Hardie DG, Kopecky J. Involvement of AMP-activated protein kinase in fat depot-specific metabolic changes during starvation. FEBS Lett 2005; 579:6105-10. [PMID: 16229840 DOI: 10.1016/j.febslet.2005.09.078] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Accepted: 09/22/2005] [Indexed: 10/25/2022]
Abstract
The mechanisms controlling fat depot-specific metabolism are poorly understood. During starvation of mice, downregulation of lipogenic genes, suppression of fatty acid synthesis, and increases in lipid oxidation were all more pronounced in epididymal than in subcutaneous fat. In epididymal fat, relatively strong upregulation of uncoupling protein 2 and phosphoenolpyruvate carboxykinase genes was found. In mice maintained both at 20 and 30 degrees C, AMP-activated protein kinase was activated in epididymal but did not change in subcutaneous fat. Our results suggest that AMPK may have a role in the different response of various fat depots to starvation.
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Affiliation(s)
- Jana Sponarova
- Department of Adipose Tissue Biology, Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, 14220 Prague, Czech Republic
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16
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Rossmeisl M, Flachs P, Brauner P, Sponarova J, Matejkova O, Prazak T, Ruzickova J, Bardova K, Kuda O, Kopecky J. Role of energy charge and AMP-activated protein kinase in adipocytes in the control of body fat stores. Int J Obes (Lond) 2004; 28 Suppl 4:S38-44. [PMID: 15592485 DOI: 10.1038/sj.ijo.0802855] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
As indicated by in vitro studies, both lipogenesis and lipolysis in adipocytes depend on the cellular ATP levels. Ectopic expression of mitochondrial uncoupling protein 1 (UCP1) in the white adipose tissue of the aP2-Ucp1 transgenic mice reduced obesity induced by genetic or dietary manipulations. Furthermore, respiratory uncoupling lowered the cellular energy charge in adipocytes, while the synthesis of fatty acids (FA) was inhibited and their oxidation increased. Importantly, the complex metabolic changes triggered by ectopic UCP1 were associated with the activation of AMP-activated protein kinase (AMPK), a metabolic master switch, in adipocytes. Effects of several typical treatments that reduce adiposity, such as administration of leptin, beta-adrenoceptor agonists, bezafibrate, dietary n-3 polyunsaturated FA or fasting, can be compared with a phenotype of the aP2-Ucp1 mice. These situations generally lead to the upregulation of mitochondrial UCPs and suppression of the cellular energy charge and FA synthesis in adipocytes. On the other hand, FA oxidation is increased. Moreover, it has been shown that AMPK in adipocytes can be activated by adipocyte-derived hormones leptin and adiponectin, and also by insulin-sensitizes thiazolidinediones. Thus, it is evident that metabolism of adipose tissue itself is important for the control of body fat content and that the cellular energy charge and AMPK are involved in the control of lipid metabolism in adipocytes. The reciprocal link between synthesis and oxidation of FA in adipocytes represents a prospective target for the new treatment strategies aimed at reducing obesity.
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Affiliation(s)
- M Rossmeisl
- Department of Adipose Tissue Biology, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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17
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Ruzickova J, Rossmeisl M, Prazak T, Flachs P, Sponarova J, Veck M, Tvrzicka E, Bryhn M, Kopecky J. Omega-3 PUFA of marine origin limit diet-induced obesity in mice by reducing cellularity of adipose tissue. Lipids 2004; 39:1177-85. [PMID: 15736913 DOI: 10.1007/s11745-004-1345-9] [Citation(s) in RCA: 214] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Omega-3 PUFA of marine origin reduce adiposity in animals fed a high-fat diet. Our aim was to learn whether EPA and DHA could limit development of obesity and reduce cellularity of adipose tissue and whether other dietary FA could influence the effect of EPA/DHA. Weight gain induced by composite high-fat diet in C57BL/6J mice was limited when the content of EPA/DHA was increased from 1 to 12% (wt/wt) of dietary lipids. Accumulation of adipose tissue was reduced, especially of the epididymal fat. Low ratio of EPA to DHA promoted the effect. A higher dose of EPA/DHA was required to reduce adiposity when admixed to diets that did not promote obesity, the semisynthetic high-fat diets rich in EFA, either alpha-linolenic acid (ALA, 18:3 n-3, the precursor of EPA and DHA) or linoleic (18:2 n-6) acid. Quantification of adipose tissue DNA revealed that except for the diet rich in ALA the reduction of epididymal fat was associated with 34-50% depression of tissue cellularity, similar to the 30% caloric restriction in the case of the high-fat composite diet. Changes in plasma markers and adipose gene expression indicated improvement of lipid and glucose metabolism due to EPA/DHA even in the context of the diet rich in ALA. Our results document augmentation of the antiadipogenic effect of EPA/DHA during development of obesity and suggest that EPA/DHA could reduce accumulation of body fat by limiting both hypertrophy and hyperplasia of fat cells. Increased dietary intake of EPA/DHA may be beneficial regardless of the ALA intake.
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Affiliation(s)
- Jana Ruzickova
- Department of Adipose Tissue Biology and Centre for Integrated Genomics, Institute of Physiology, Academy of Sciences of the Czech Republic, 142 20 Prague, Czech Republic
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18
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Matejkova O, Mustard KJ, Sponarova J, Flachs P, Rossmeisl M, Miksik I, Thomason-Hughes M, Grahame Hardie D, Kopecky J. Possible involvement of AMP-activated protein kinase in obesity resistance induced by respiratory uncoupling in white fat. FEBS Lett 2004; 569:245-8. [PMID: 15225642 DOI: 10.1016/j.febslet.2004.06.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Revised: 05/14/2004] [Accepted: 06/03/2004] [Indexed: 11/13/2022]
Abstract
The AMP-activated protein kinase (AMPK) cascade is a sensor of cellular energy charge that promotes catabolic and inhibits anabolic pathways. However, the role of AMPK in adipocytes is poorly understood. We show that transgenic expression of mitochondrial uncoupling protein 1 in white fat, which induces obesity resistance in mice, is associated with depression of cellular energy charge, activation of AMPK, downregulation of adipogenic genes, and increase in lipid oxidation. Activation of AMPK may explain the complex metabolic changes in adipose tissue of these animals and our results support a role for adipocyte AMPK in the regulation of storage of body fat.
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Affiliation(s)
- Olga Matejkova
- Department of Adipose Tissue Biology and Center for Integrated Genomics, Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, 14220 Prague, Czech Republic
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