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PET/MRI-Evaluated Activation of Brown Adipose Tissue via Cold Exposure Impacts Lipid Metabolism. Metabolites 2022; 12:metabo12050456. [PMID: 35629960 PMCID: PMC9145038 DOI: 10.3390/metabo12050456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 02/04/2023] Open
Abstract
Although brown adipose tissue (BAT) is considered to play a protective role against obesity and type 2 diabetes, the mechanisms of its activation and associations with clinical parameters are not well described. Male adults underwent a 2 h cold exposure (CE) to activate BAT and, based on the results of PET/MRI performed after the CE, were divided into BAT(+) and BAT(−) groups. During the CE procedure, blood samples were collected and alterations in plasma metabolome in both groups were investigated using LC-MS. Additionally, associations between clinical factors and BAT were examined. Moreover, levels of glucose, insulin, leptin, TNF-α, FGF21, and FABP4 were assessed in serum samples. In the BAT(+) group, levels of LPC(17:0), LPE(20:4), LPE(22:4), LPE(22:6), DHA, linoleic acid, and oleic acid increased during CE, whereas levels of sphinganine-phosphate and sphingosine-1-phosphate decreased. Levels of LPE(O-18:0), 9-HpODE, and oleic acid were elevated, while the level of LPE(20:5) was reduced in BAT(+) compared to BAT(−) subjects. AUCs of LPC(18:2), LPC(O-18:2)/LPC(P-18:1), and SM(d32:2) negatively correlated with BAT. In the BAT(+) group, the concentration of FABP4 during and after CE was decreased compared to the basal level. No alterations were observed in the BAT(−) group. In conclusion, using untargeted metabolomics, we proved that the plasma metabolome is affected by cold-induced BAT activation.
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Zoico E, Rubele S, De Caro A, Nori N, Mazzali G, Fantin F, Rossi A, Zamboni M. Brown and Beige Adipose Tissue and Aging. Front Endocrinol (Lausanne) 2019; 10:368. [PMID: 31281288 PMCID: PMC6595248 DOI: 10.3389/fendo.2019.00368] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 05/23/2019] [Indexed: 01/24/2023] Open
Abstract
Across aging, adipose tissue (AT) changes its quantity and distribution: AT becomes dysfunctional with an increase in production of inflammatory peptides, a decline of those with anti-inflammatory activity and infiltration of macrophages. Adipose organ dysfunction may lead to age-related metabolic alterations. Aging is characterized by an increase in adiposity and a decline in brown adipose tissue (BAT) depots and activity, and UCP1 expression. There are many possible links to age-associated involution of BAT, including the loss of mitochondrial function, impairment of the sympathetic nervous system, age-induced alteration of brown adipogenic stem/progenitor cell function and changes in endocrine signals. Aging is also associated with a reduction in beige adipocyte formation. Beige adipocytes are known to differentiate from a sub-population of progenitors resident in white adipose tissue (WAT); a defective ability of progenitor cells to proliferate and differentiate has been hypothesized with aging. The loss of beige adipocytes with age may be caused by changes in trophic factors in the adipose tissue microenvironment, which regulate progenitor cell proliferation and differentiation. This review focuses on possible mechanisms involved in the reduction of BAT and beige activity with aging, along with possible targets for age-related metabolic disease therapy.
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Affiliation(s)
- Elena Zoico
- Division of Geriatric Medicine, Department of Medicine, University of Verona, Verona, Italy
- *Correspondence: Elena Zoico
| | - Sofia Rubele
- Division of Geriatric Medicine, Department of Medicine, University of Verona, Verona, Italy
| | - Annamaria De Caro
- Division of Geriatric Medicine, Department of Medicine, University of Verona, Verona, Italy
| | - Nicole Nori
- Division of Geriatric Medicine, Department of Medicine, University of Verona, Verona, Italy
| | - Gloria Mazzali
- Division of Geriatric Medicine, Department of Medicine, University of Verona, Verona, Italy
| | - Francesco Fantin
- Division of Geriatric Medicine, Department of Medicine, University of Verona, Verona, Italy
| | - Andrea Rossi
- Division of Geriatric Medicine, Department of Medicine, University of Verona, Verona, Italy
| | - Mauro Zamboni
- Division of Geriatric Medicine, Department of Surgery, Dentistry, Pediatric and Gynecology, University of Verona, Verona, Italy
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Lima D, Zacchi FL, Mattos JJ, Flores-Nunes F, Gomes CHADM, de Mello ÁCP, Siebert MN, Piazza CE, Taniguchi S, Sasaki ST, Bícego MC, Bebianno MJ, de Almeida EA, Bainy ACD. Molecular and cellular effects of temperature in oysters Crassostrea brasiliana exposed to phenanthrene. CHEMOSPHERE 2018; 209:307-318. [PMID: 29933167 DOI: 10.1016/j.chemosphere.2018.06.094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 06/11/2018] [Accepted: 06/12/2018] [Indexed: 06/08/2023]
Abstract
Exposure of aquatic organisms to polycyclic aromatic hydrocarbons (PAH), such as phenanthrene (PHE), may increase the production of reactive oxygen species (ROS) and cause changes in the biotransformation systems. In addition, changes in water temperature can cause adverse effects in the organisms. Estuarine species, like the oyster Crassostrea brasiliana, can adapt and tolerate temperature variation. To evaluate the influence of temperature on biological responses of C. brasiliana exposed to PHE, oysters were maintained at three temperatures (18, 24 and 32 °C) for 15 days and co-exposed afterwards to 100 μg.L-1 of PHE for 24 and 96 h. Levels of PHE in the water and oyster tissues were determined, respectively after 24 and 96 h. In addition, thermal stress, biotransformation and oxidative stress-related genes were analyzed in oyster gills, together with the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferases (GST) and levels of lipid peroxidation. Oyster accumulated significant levels of PHE. HSP70-like transcripts were affected by PHE exposure only at 32 °C. Transcript levels of cytochrome P450 isoforms (CYP2-like2 and CYP2AU1) were down-regulated in oysters exposed to PHE for 24 h at 32 °C. GSTΩ-like transcript levels were also down-regulated in the PHE-exposed group at 32 °C. After 96 h, CYP2-like2 transcripts were higher in the PHE exposed groups at 32 °C. Oysters kept at 18 °C showed higher levels of SOD-like transcripts, together with higher GST, GPx and G6PDH activities, associated to lower levels of lipoperoxidation. In general the biological responses evaluated were more affected by temperature, than by co-exposure to PHE.
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Affiliation(s)
- Daína Lima
- Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry, Department of Biochemistry, Federal University of Santa Catarina, UFSC, Florianópolis, SC, Brazil
| | - Flávia Lucena Zacchi
- Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry, Department of Biochemistry, Federal University of Santa Catarina, UFSC, Florianópolis, SC, Brazil
| | - Jacó Joaquim Mattos
- Aquaculture Pathology Research, NEPAQ, Federal University of Santa Catarina, Florianópolis, SC, Brazil
| | - Fabrício Flores-Nunes
- Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry, Department of Biochemistry, Federal University of Santa Catarina, UFSC, Florianópolis, SC, Brazil
| | - Carlos Henrique Araújo de Miranda Gomes
- Laboratory of Marine Mollusks (LMM), Department of Aquaculture, Center of Agricultural Science, Federal University of Santa Catarina, Florianópolis, SC, Brazil
| | - Álvaro Cavaler Pessoa de Mello
- Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry, Department of Biochemistry, Federal University of Santa Catarina, UFSC, Florianópolis, SC, Brazil
| | - Marília Nardelli Siebert
- Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry, Department of Biochemistry, Federal University of Santa Catarina, UFSC, Florianópolis, SC, Brazil
| | - Clei Endrigo Piazza
- Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry, Department of Biochemistry, Federal University of Santa Catarina, UFSC, Florianópolis, SC, Brazil
| | - Satie Taniguchi
- Laboratory of Marine Organic Chemistry, Oceanographic Institute, University of São Paulo, São Paulo, Brazil
| | - Silvio Tarou Sasaki
- Laboratory of Marine Organic Chemistry, Oceanographic Institute, University of São Paulo, São Paulo, Brazil
| | - Márcia Caruso Bícego
- Laboratory of Marine Organic Chemistry, Oceanographic Institute, University of São Paulo, São Paulo, Brazil
| | - Maria João Bebianno
- Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry, Department of Biochemistry, Federal University of Santa Catarina, UFSC, Florianópolis, SC, Brazil; CIMA, University of Algarve, Campus de Gambelas, 8000-139 Faro, Portugal
| | - Eduardo Alves de Almeida
- Department of Natural Sciences, Fundação Universidade Regional de Blumenau, Blumenau, SC, Brazil
| | - Afonso Celso Dias Bainy
- Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry, Department of Biochemistry, Federal University of Santa Catarina, UFSC, Florianópolis, SC, Brazil.
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Hiroshima Y, Yamamoto T, Watanabe M, Baba Y, Shinohara Y. Effects of cold exposure on metabolites in brown adipose tissue of rats. Mol Genet Metab Rep 2018; 15:36-42. [PMID: 30023288 PMCID: PMC6047462 DOI: 10.1016/j.ymgmr.2018.01.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 01/26/2018] [Accepted: 01/26/2018] [Indexed: 01/10/2023] Open
Abstract
Brown adipose tissue (BAT) plays an important role in regulation of energy expenditure while adapting to a cold environment. BAT thermogenesis depends on uncoupling protein 1 (UCP1), which is expressed in the inner mitochondrial membranes of BAT. Gene expression profiles induced by cold exposure in BAT have been studied, but the metabolomic biological pathway that contributes to the activation of thermogenesis in BAT remains unclear. In this study, we comprehensively compared the relative levels of metabolites between the BAT of rats kept at room temperature (22 °C) and of those exposed to a cold temperature (4 °C) for 48 h using capillary electrophoresis (CE) time-of-flight mass spectrometry (TOFMS) and liquid chromatography (LC)-TOFMS. We identified 218 metabolites (137 cations and 81 anions) by CE-TOFMS and detected 81 metabolites (47 positive and 34 negative) by LC-TOFMS in BAT. We found that cold exposure highly influenced the BAT metabolome. We showed that the cold environment lead to lower levels of glycolysis and gluconeogenesis intermediates and higher levels of the tricarboxylic acid (TCA) cycle metabolites, fatty acids, and acyl-carnitine metabolites than control conditions in the BAT of rats. These results indicate that glycolysis and β-oxidation of fatty acids in BAT are positive biological pathways that contribute to the activation of thermogenesis by cold exposure, thereby facilitating the generation of heat by UCP1. These data provide useful information for understanding the basal metabolic functions of BAT thermogenesis in rats in response to cold exposure.
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Affiliation(s)
- Yuka Hiroshima
- Institute for Genome Research, Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Takenori Yamamoto
- Institute for Genome Research, Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
- Faculty of Pharmaceutical Science, University of Tokushima, 1-78 Shomachi, Tokushima 770-8505, Japan
| | - Masahiro Watanabe
- School of Pharmacy, Shujitsu University, 1-6-1 Nishigawara, Naka-ku, Okayama 703-8516, Japan
| | - Yoshinobu Baba
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
- ImPACT Research Center for Advanced Nanobiodevices, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
- Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu 761-0395, Japan
| | - Yasuo Shinohara
- Institute for Genome Research, Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
- Faculty of Pharmaceutical Science, University of Tokushima, 1-78 Shomachi, Tokushima 770-8505, Japan
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Labbé SM, Caron A, Bakan I, Laplante M, Carpentier AC, Lecomte R, Richard D. In vivo measurement of energy substrate contribution to cold-induced brown adipose tissue thermogenesis. FASEB J 2015; 29:2046-58. [PMID: 25681456 DOI: 10.1096/fj.14-266247] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 12/30/2014] [Indexed: 11/11/2022]
Abstract
The present study was designed to investigate the effects of cold on brown adipose tissue (BAT) energy substrate utilization in vivo using the positron emission tomography tracers [(18)F]fluorodeoxyglucose (glucose uptake), 14(R,S)-[(18)F]fluoro-6-thia-heptadecanoic acid [nonesterified fatty acid (NEFA) uptake], and [(11)C]acetate (oxidative activity). The measurements were performed in rats adapted to 27°C, which were acutely subjected to cold (10°C) for 2 and 6 hours, and in rats chronically adapted to 10°C for 21 days, which were returned to 27°C for 2 and 6 hours. Cold exposure (acutely and chronically) led to increases in BAT oxidative activity, which was accompanied by concomitant increases in glucose and NEFA uptake. The increases were particularly high in cold-adapted rats and largely readily reduced by the return to a warm environment. The cold-induced increase in oxidative activity was meaningfully blunted by nicotinic acid, a lipolysis inhibitor, which emphasizes in vivo the key role of intracellular lipid in BAT thermogenesis. The changes in BAT oxidative activity and glucose and NEFA uptakes were paralleled by inductions of genes involved in not only oxidative metabolism but also in energy substrate replenishment (triglyceride and glycogen synthesis). The capacity of BAT for energy substrate replenishment is remarkable.
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Affiliation(s)
- Sébastien M Labbé
- *Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada; Department of Medicine, Centre de Recherche du Centre Hospitalier, and Departments of Nuclear Medicine and Radiobiology, Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
| | - Alexandre Caron
- *Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada; Department of Medicine, Centre de Recherche du Centre Hospitalier, and Departments of Nuclear Medicine and Radiobiology, Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
| | - Inan Bakan
- *Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada; Department of Medicine, Centre de Recherche du Centre Hospitalier, and Departments of Nuclear Medicine and Radiobiology, Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
| | - Mathieu Laplante
- *Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada; Department of Medicine, Centre de Recherche du Centre Hospitalier, and Departments of Nuclear Medicine and Radiobiology, Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
| | - André C Carpentier
- *Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada; Department of Medicine, Centre de Recherche du Centre Hospitalier, and Departments of Nuclear Medicine and Radiobiology, Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
| | - Roger Lecomte
- *Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada; Department of Medicine, Centre de Recherche du Centre Hospitalier, and Departments of Nuclear Medicine and Radiobiology, Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
| | - Denis Richard
- *Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada; Department of Medicine, Centre de Recherche du Centre Hospitalier, and Departments of Nuclear Medicine and Radiobiology, Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
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6
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Townsend KL, Tseng YH. Brown fat fuel utilization and thermogenesis. Trends Endocrinol Metab 2014; 25:168-77. [PMID: 24389130 PMCID: PMC3972344 DOI: 10.1016/j.tem.2013.12.004] [Citation(s) in RCA: 225] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 11/29/2013] [Accepted: 12/02/2013] [Indexed: 12/16/2022]
Abstract
Brown adipose tissue (BAT) dissipates energy as heat to maintain optimal thermogenesis and to contribute to energy expenditure in rodents and possibly humans. The energetic processes executed by BAT require a readily-available fuel supply, which includes glucose and fatty acids (FAs). FAs become available by cellular uptake, de novo lipogenesis, and multilocular lipid droplets in brown adipocytes. BAT also possesses a great capacity for glucose uptake and metabolism, and an ability to regulate insulin sensitivity. These properties make BAT an appealing target for the treatment of obesity, diabetes, and other metabolic disorders. Recent research has provided a better understanding of the processes of fuel utilization carried out by brown adipocytes, which is the focus of the current review.
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Affiliation(s)
- Kristy L Townsend
- Joslin Diabetes Center and Harvard Medical School, One Joslin Place, Boston, MA 02215, USA
| | - Yu-Hua Tseng
- Joslin Diabetes Center and Harvard Medical School, One Joslin Place, Boston, MA 02215, USA; Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA.
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Syamsunarno MRAA, Iso T, Yamaguchi A, Hanaoka H, Putri M, Obokata M, Sunaga H, Koitabashi N, Matsui H, Maeda K, Endo K, Tsushima Y, Yokoyama T, Kurabayashi M. Fatty acid binding protein 4 and 5 play a crucial role in thermogenesis under the conditions of fasting and cold stress. PLoS One 2014; 9:e90825. [PMID: 24603714 PMCID: PMC3946242 DOI: 10.1371/journal.pone.0090825] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 02/04/2014] [Indexed: 12/30/2022] Open
Abstract
Hypothermia is rapidly induced during cold exposure when thermoregulatory mechanisms, including fatty acid (FA) utilization, are disturbed. FA binding protein 4 (FABP4) and FABP5, which are abundantly expressed in adipose tissues and macrophages, have been identified as key molecules in the pathogenesis of overnutrition-related diseases, such as insulin resistance and atherosclerosis. We have recently shown that FABP4/5 are prominently expressed in capillary endothelial cells in the heart and skeletal muscle and play a crucial role in FA utilization in these tissues. However, the role of FABP4/5 in thermogenesis remains to be determined. In this study, we showed that thermogenesis is severely impaired in mice lacking both FABP4 and FABP5 (DKO mice), as manifested shortly after cold exposure during fasting. In DKO mice, the storage of both triacylglycerol in brown adipose tissue (BAT) and glycogen in skeletal muscle (SkM) was nearly depleted after fasting, and a biodistribution analysis using 125I-BMIPP revealed that non-esterified FAs (NEFAs) are not efficiently taken up by BAT despite the robustly elevated levels of serum NEFAs. In addition to the severe hypoglycemia observed in DKO mice during fasting, cold exposure did not induce the uptake of glucose analogue 18F-FDG by BAT. These findings strongly suggest that DKO mice exhibit pronounced hypothermia after fasting due to the depletion of energy storage in BAT and SkM and the reduced supply of energy substrates to these tissues. In conclusion, FABP4/5 play an indispensable role in thermogenesis in BAT and SkM. Our study underscores the importance of FABP4/5 for overcoming life-threatening environments, such as cold and starvation.
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Affiliation(s)
| | - Tatsuya Iso
- Department of Medicine and Biological Science, Gunma University Graduate School of Medicine, Gunma, Japan
- Education and Research Support Center, Gunma University Graduate School of Medicine, Gunma, Japan
- * E-mail:
| | - Aiko Yamaguchi
- Department of Bioimaging Information Analysis, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Hirofumi Hanaoka
- Department of Molecular Imaging and Radiotherapy, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Mirasari Putri
- Department of Medicine and Biological Science, Gunma University Graduate School of Medicine, Gunma, Japan
- Department of Public Health, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Masaru Obokata
- Department of Medicine and Biological Science, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Hiroaki Sunaga
- Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, Gunma, Japan
| | - Norimichi Koitabashi
- Department of Medicine and Biological Science, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Hiroki Matsui
- Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, Gunma, Japan
| | - Kazuhisa Maeda
- Department of Complementary and Alternative Medicine, Graduate School of Medicine, Osaka University Hospital, Osaka, Japan
| | - Keigo Endo
- Department of Bioimaging Information Analysis, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Yoshito Tsushima
- Department of Diagnostic Radiology and Nuclear Medicine, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Tomoyuki Yokoyama
- Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, Gunma, Japan
| | - Masahiko Kurabayashi
- Department of Medicine and Biological Science, Gunma University Graduate School of Medicine, Gunma, Japan
- Education and Research Support Center, Gunma University Graduate School of Medicine, Gunma, Japan
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Comparison of the catalytic activities of three isozymes of carnitine palmitoyltransferase 1 expressed in COS7 cells. Appl Biochem Biotechnol 2013; 172:1486-96. [PMID: 24222496 DOI: 10.1007/s12010-013-0619-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 10/30/2013] [Indexed: 12/30/2022]
Abstract
The enzyme carnitine palmitoyltransferase 1 (CPT1) catalyzes the transfer of an acyl group from acyl-CoA to carnitine to form acylcarnitine, and three isozymes of it, 1a, 1b, and 1c, have been identified. Interestingly, the 1c isozyme was reported to show no enzymatic activity, but it was not clearly demonstrated whether this inactivity was due to its dysfunction or due to its poor expression. In the present study, we (a) expressed individual CPT1 isozymes in COS7 cells, (b) evaluated quantitatively their expression levels by Western blotting using the three bacterially expressed CPT1 isozymes as standards, and (c) evaluated their catalytic activities. With these experiments, we successfully demonstrated that the absence of the enzymatic activity of the 1c isozyme was due to its dysfunction. In addition, experiments on the preparation of standard CPT1 isozymes revealed that the 1c isozyme did not show the standard relationship between migration in an SDS-PAGE gel and molecular size. We further tried to determine why the 1c isozyme was inert by preparing chimeric CPT1 between 1a and 1c, but no clear conclusion could be drawn because one of the chimeric CPT1s was not sufficiently expressed.
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Nakamura Y, Sato T, Shiimura Y, Miura Y, Kojima M. FABP3 and brown adipocyte-characteristic mitochondrial fatty acid oxidation enzymes are induced in beige cells in a different pathway from UCP1. Biochem Biophys Res Commun 2013; 441:42-6. [PMID: 24129192 DOI: 10.1016/j.bbrc.2013.10.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 10/04/2013] [Indexed: 11/19/2022]
Abstract
Cold exposure and β3-adrenergic receptor agonist (CL316,243) treatment induce the production of beige cells, which express brown adipocytes(BA)-specific UCP1 protein, in white adipose tissue (WAT). It remains unclear whether the beige cells, which have different gene expression patterns from BA, express BA-characteristic fatty acid oxidation (FAO) proteins. Here we found that 5 day cold exposure and CL316,243 treatment of WAT, but not CL316,243 treatment of primary adipocytes of C57BL/6J mice, increased mRNA levels of BA-characteristic FAO proteins. These results suggest that BA-characteristic FAO proteins are induced in beige cells in a different pathway from UCP1.
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Affiliation(s)
- Yuki Nakamura
- Department of Molecular Genetics, Institute of Life Science, Kurume University, 1-1 Hyakunen-kouen, Kurume 839-0864, Japan
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10
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Cold-induced changes in gene expression in brown adipose tissue, white adipose tissue and liver. PLoS One 2013; 8:e68933. [PMID: 23894377 PMCID: PMC3718809 DOI: 10.1371/journal.pone.0068933] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 06/05/2013] [Indexed: 01/30/2023] Open
Abstract
Cold exposure imposes a metabolic challenge to mammals that is met by a coordinated response in different tissues to prevent hypothermia. This study reports a transcriptomic analysis in brown adipose tissue (BAT), white adipose (WAT) and liver of mice in response to 24 h cold exposure at 8°C. Expression of 1895 genes were significantly (P<0.05) up- or down-regulated more than two fold by cold exposure in all tissues but only 5 of these genes were shared by all three tissues, and only 19, 14 and 134 genes were common between WAT and BAT, WAT and liver, and BAT and liver, respectively. We confirmed using qRT-PCR, the increased expression of a number of characteristic BAT genes during cold exposure. In both BAT and the liver, the most common direction of change in gene expression was suppression (496 genes in BAT and 590 genes in liver). Gene ontology analysis revealed for the first time significant (P<0.05) down regulation in response to cold, of genes involved in oxidoreductase activity, lipid metabolic processes and protease inhibitor activity, in both BAT and liver, but not WAT. The results reveal an unexpected importance of down regulation of cytochrome P450 gene expression and apolipoprotein, in both BAT and liver, but not WAT, in response to cold exposure. Pathway analysis suggests a model in which down regulation of the nuclear transcription factors HNF4α and PPARα in both BAT and liver may orchestrate the down regulation of genes involved in lipoprotein and steroid metabolism as well as Phase I enzymes belonging to the cytochrome P450 group in response to cold stress in mice. We propose that the response to cold stress involves decreased gene expression in a range of cellular processes in order to maximise pathways involved in heat production.
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