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Friedman MI, Sørensen TIA, Taubes G, Lund J, Ludwig DS. Trapped fat: Obesity pathogenesis as an intrinsic disorder in metabolic fuel partitioning. Obes Rev 2024; 25:e13795. [PMID: 38961319 DOI: 10.1111/obr.13795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 05/24/2024] [Accepted: 06/13/2024] [Indexed: 07/05/2024]
Abstract
Our understanding of the pathophysiology of obesity remains at best incomplete despite a century of research. During this time, two alternative perspectives have helped shape thinking about the etiology of the disorder. The currently prevailing view holds that excessive fat accumulation results because energy intake exceeds energy expenditure, with excessive food consumption being the primary cause of the imbalance. The other perspective attributes the initiating cause of obesity to intrinsic metabolic defects that shift fuel partitioning from pathways for mobilization and oxidation to those for synthesis and storage. The resulting reduction in fuel oxidation and trapping of energy in adipose tissue drives a compensatory increase in energy intake and, under some conditions, a decrease in expenditure. This theory of obesity pathogenesis has historically garnered relatively less attention despite its pedigree. Here, we present an updated comprehensive formulation of the fuel partitioning theory, focused on evidence gathered over the last 80 years from major animal models of obesity showing a redirection of fuel fluxes from oxidation to storage and accumulation of excess body fat with energy intake equal to or even less than that of lean animals. The aim is to inform current discussions about the etiology of obesity and by so doing, help lay new foundations for the design of more efficacious approaches to obesity research, treatment and prevention.
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Affiliation(s)
| | - Thorkild I A Sørensen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Department of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Center for Childhood Health, Copenhagen, Denmark
| | | | - Jens Lund
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - David S Ludwig
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, Department of Pediatrics, Harvard Medical School, Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
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2
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Canet G, Gratuze M, Zussy C, Bouali ML, Diaz SD, Rocaboy E, Laliberté F, El Khoury NB, Tremblay C, Morin F, Calon F, Hébert SS, Julien C, Planel E. Age-dependent impact of streptozotocin on metabolic endpoints and Alzheimer's disease pathologies in 3xTg-AD mice. Neurobiol Dis 2024; 198:106526. [PMID: 38734152 DOI: 10.1016/j.nbd.2024.106526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/06/2024] [Accepted: 05/07/2024] [Indexed: 05/13/2024] Open
Abstract
Alzheimer's disease (AD) is a multifactorial neurodegenerative disease with a complex origin, thought to involve a combination of genetic, biological and environmental factors. Insulin dysfunction has emerged as a potential factor contributing to AD pathogenesis, particularly in individuals with diabetes, and among those with insulin deficiency or undergoing insulin therapy. The intraperitoneal administration of streptozotocin (STZ) is widely used in rodent models to explore the impact of insulin deficiency on AD pathology, although prior research predominantly focused on young animals, with no comparative analysis across different age groups. Our study aimed to fill this gap by analyzing the impact of insulin dysfunction in 7 and 23 months 3xTg-AD mice, that exhibit both amyloid and tau pathologies. Our objective was to elucidate the age-specific consequences of insulin deficiency on AD pathology. STZ administration led to insulin deficiency in the younger mice, resulting in an increase in cortical amyloid-β (Aβ) and tau aggregation, while tau phosphorylation was not significantly affected. Conversely, older mice displayed an unexpected resilience to the peripheral metabolic impact of STZ, while exhibiting an increase in both tau phosphorylation and aggregation without significantly affecting amyloid pathology. These changes were paralleled with alterations in signaling pathways involving tau kinases and phosphatases. Several markers of blood-brain barrier (BBB) integrity declined with age in 3xTg-AD mice, which might have facilitated a direct neurotoxic effect of STZ in older mice. Overall, our research confirms the influence of insulin signaling dysfunction on AD pathology, but also advises careful interpretation of data related to STZ-induced effects in older animals.
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Affiliation(s)
- Geoffrey Canet
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada; Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada.
| | - Maud Gratuze
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada; Institute of Neurophysiopathology (INP), University of Aix-Marseille, CNRS UMR 7051, 13385 Marseille, France.
| | - Charleine Zussy
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada; Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada.
| | - Mohamed Lala Bouali
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada.
| | - Sofia Diego Diaz
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada.
| | - Emma Rocaboy
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada.
| | - Francis Laliberté
- Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada
| | - Noura B El Khoury
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada; University of Balamand, Faculty of Arts and Sciences, Departement of Psychology, Tueini Building Kalhat, Al-Kurah, P.O. Box 100, Tripoli, Lebanon.
| | - Cyntia Tremblay
- Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada.
| | - Françoise Morin
- Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada.
| | - Frédéric Calon
- Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada; Laval University, Faculty of Pharmacy, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada.
| | - Sébastien S Hébert
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada; Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada.
| | - Carl Julien
- Research Center in Animal Sciences of Deschambault, Québec, QC G0A 1S0, Canada; Laval University, Faculty of Agricultural and Food Sciences, Québec, QC G1V 0A6, Canada.
| | - Emmanuel Planel
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada; Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada.
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3
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Dumont L, Caron A, Richard G, Croteau E, Fortin M, Frisch F, Phoenix S, Dubreuil S, Guérin B, Turcotte ÉE, Carpentier AC, Blondin DP. The effects of the β 1-adrenergic receptor antagonist bisoprolol administration on mirabegron-stimulated human brown adipose tissue thermogenesis. Acta Physiol (Oxf) 2024; 240:e14127. [PMID: 38502056 DOI: 10.1111/apha.14127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 01/25/2024] [Accepted: 02/27/2024] [Indexed: 03/20/2024]
Abstract
AIM Pharmacological stimulation of human brown adipose tissue (BAT) has been hindered by ineffective activation or undesirable off-target effects. Oral administration of the maximal allowable dose of mirabegron (200 mg), a β3-adrenergic receptor (β3-AR) agonist, has been effective in stimulating BAT thermogenesis and whole-body energy expenditure. However, this has been accompanied by undesirable cardiovascular effects. Therefore, we hypothesized that combining mirabegron with a β1-AR antagonist could suppress these unwanted effects and increase the stimulation of the β3-AR and β2-AR in BAT. METHODS We performed a randomized crossover trial (NCT04823442) in 8 lean men. Mirabegron (200 mg) was administered orally with or without the β1-AR antagonist bisoprolol (10 mg). Dynamic [11C]-acetate and 2-deoxy-2-[18F]fluoro-d-glucose PET/CT scans were performed sequentially after oral administration of mirabegron ± bisoprolol. RESULTS Compared to room temperature, mirabegron alone increased BAT oxidative metabolism (0.84 ± 0.46 vs. 1.79 ± 0.91 min-1, p = 0.0433), but not when combined with bisoprolol. The metabolic rate of glucose in BAT, measured using [18F]FDG PET, was significantly higher with mirabegron than mirabegron with bisoprolol (24 ± 10 vs. 16 ± 8 nmol/g/min, p = 0.0284). Bisoprolol inhibited the mirabegron-induced increase in systolic blood pressure and heart rate. CONCLUSION The administration of bisoprolol decreases the adverse cardiovascular effects of mirabegron. However, the provided dose also blunted the mirabegron-stimulated increase in BAT lipolysis, thermogenesis, and glucose uptake. The attenuation in BAT blood flow induced by the large dose of bisoprolol may have limited BAT thermogenesis.
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Affiliation(s)
- Lauralyne Dumont
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Québec, Canada
- Department of Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Alexandre Caron
- Faculty of Pharmacy, Université Laval, Quebec City, Québec, Canada
- Quebec Heart and Lung Institute, Quebec City, Québec, Canada
- Montreal Diabetes Research Center, Montreal, Québec, Canada
| | - Gabriel Richard
- Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Etienne Croteau
- Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Mélanie Fortin
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Québec, Canada
| | - Frédérique Frisch
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Québec, Canada
| | - Serge Phoenix
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Québec, Canada
- Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Stéphanie Dubreuil
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Québec, Canada
| | - Brigitte Guérin
- Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Éric E Turcotte
- Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - André C Carpentier
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Québec, Canada
- Division of Endocrinology, Department of Medicine, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Denis P Blondin
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Québec, Canada
- Division of Neurology, Department of Medicine, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
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Lee J, Song Y, Kim YA, Kim I, Cha J, Lee SW, Ko Y, Kim CS, Kim S, Lee S. Characterization of a new selective glucocorticoid receptor modulator with anorexigenic activity. Sci Rep 2024; 14:7844. [PMID: 38570726 PMCID: PMC10991430 DOI: 10.1038/s41598-024-58546-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Accepted: 04/01/2024] [Indexed: 04/05/2024] Open
Abstract
Obesity, a worldwide epidemic, leads to various metabolic disorders threatening human health. In response to stress or fasting, glucocorticoid (GC) levels are elevated to promote food intake. This involves GC-induced expression of the orexigenic neuropeptides in agouti-related protein (AgRP) neurons of the hypothalamic arcuate nucleus (ARC) via the GC receptor (GR). Here, we report a selective GR modulator (SGRM) that suppresses GR-induced transcription of genes with non-classical glucocorticoid response elements (GREs) such as Agrp-GRE, but not with classical GREs, and via this way may serve as a novel anti-obesity agent. We have identified a novel SGRM, 2-O-trans-p-coumaroylalphitolic acid (Zj7), a triterpenoid extracted from the Ziziphus jujube plant, that selectively suppresses GR transcriptional activity in Agrp-GRE without affecting classical GREs. Zj7 reduces the expression of orexigenic genes in the ARC and exerts a significant anorexigenic effect with weight loss in both high fat diet-induced obese and genetically obese db/db mouse models. Transcriptome analysis showed that Zj7 represses the expression of a group of orexigenic genes including Agrp and Npy induced by the synthetic GR ligand dexamethasone (Dex) in the hypothalamus. Taken together, Zj7, as a selective GR modulator, showed beneficial metabolic activities, in part by suppressing GR activity in non-classical GREs in orexigenic genes. This study demonstrates that a potential anorexigenic molecule may allow GRE-specific inhibition of GR transcriptional activity, which is a promising approach for the treatment of metabolic disorders.
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Affiliation(s)
- Junekyoung Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Korea
| | - Yeonghun Song
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Korea
| | - Young A Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Korea
| | - Intae Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Korea
| | - Jooseon Cha
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Korea
| | - Su Won Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Korea
| | - Yoonae Ko
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Korea
| | - Chong-Su Kim
- Department of Food and Nutrition, College of Natural Information Sciences, Dongduk Women's University, Seoul, 02748, Korea
| | - Sanghee Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Korea.
| | - Seunghee Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Korea.
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Peurière L, Mastrandrea C, Vanden-Bossche A, Linossier MT, Thomas M, Normand M, Lafage-Proust MH, Vico L. Hindlimb unloading in C57BL/6J mice induces bone loss at thermoneutrality without change in osteocyte and lacuno-canalicular network. Bone 2023; 169:116640. [PMID: 36526262 DOI: 10.1016/j.bone.2022.116640] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/13/2022] [Accepted: 11/30/2022] [Indexed: 12/15/2022]
Abstract
Impaired mechanical stimuli during hindlimb unloading (HLU) are believed to exacerbate osteocyte paracrine regulation of osteoclasts. We hypothesized that bone loss and deterioration of the osteocyte lacuno-canalicular network are attenuated in HLU mice housed at thermoneutrality (28 °C) compared with those housed at ambient temperature (22 °C). Following acclimatization, 20-week-old male C57BL/6J mice were submitted to HLU or kept in pair-fed control cages (CONT), for 5 days (5d) or 14d, at 22 °C or 28 °C. In the femur distal metaphysis, thermoneutral CONT mice had higher bone volume (p = 0.0007, BV/TV, in vivo μCT, vs. 14dCONT22) whilst osteoclastic surfaces of CONT and HLU were greater at 22 °C (5dCONT22 + 53 %, 5dHLU22 + 50 %, 14dCONT22 + 186 %, 14dHLU22 + 104 %, vs matching 28 °C group). In the femur diaphysis and at both temperatures, 14dHLU exhibited thinner cortices distally or proximally compared to controls; the mid-diaphysis being thicker at 28 °C than at 22 °C in all groups. Expression of cortical genes for proteolytic enzyme (Mmp13), markers for osteoclastogenic differentiation (MCSF, RANKL), and activity (TRAP, Ctsk) were increased following 22 °C HLU, whereas only Ctsk expression was increased following 28 °C HLU. Expression of cortical genes for apoptosis, senescence, and autophagy were not elevated following HLU at any temperature. Osteocyte density at the posterior mid-diaphysis was similar between groups, as was the proportion of empty lacunae (<0.5 %). However, analysis of the lacuno-canalicular network (LCN, fluorescein staining) revealed unstained areas in the 14dHLU22 group only, suggesting disrupted LCN flow in this group alone. In conclusion, 28 °C housing influences the HLU bone response but does not prevent bone loss. Furthermore, our results do not show osteocyte senescence or death, and at thermoneutrality, HLU-induced bone resorption is not triggered by osteoclastic activators RANKL and MCSF.
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Affiliation(s)
- Laura Peurière
- Université Jean Monnet Saint-Étienne, Mines Saint-Étienne, INSERM, SAINBIOSE U1059, F-42023, Saint-Étienne, France.
| | - Carmelo Mastrandrea
- Université Jean Monnet Saint-Étienne, Mines Saint-Étienne, INSERM, SAINBIOSE U1059, F-42023, Saint-Étienne, France
| | - Arnaud Vanden-Bossche
- Université Jean Monnet Saint-Étienne, Mines Saint-Étienne, INSERM, SAINBIOSE U1059, F-42023, Saint-Étienne, France
| | - Marie-Thérèse Linossier
- Université Jean Monnet Saint-Étienne, Mines Saint-Étienne, INSERM, SAINBIOSE U1059, F-42023, Saint-Étienne, France
| | - Mireille Thomas
- Université Jean Monnet Saint-Étienne, Mines Saint-Étienne, INSERM, SAINBIOSE U1059, F-42023, Saint-Étienne, France
| | - Myriam Normand
- Université Jean Monnet Saint-Étienne, Mines Saint-Étienne, INSERM, SAINBIOSE U1059, F-42023, Saint-Étienne, France
| | - Marie-Hélène Lafage-Proust
- Université Jean Monnet Saint-Étienne, Mines Saint-Étienne, INSERM, SAINBIOSE U1059, F-42023, Saint-Étienne, France
| | - Laurence Vico
- Université Jean Monnet Saint-Étienne, Mines Saint-Étienne, INSERM, SAINBIOSE U1059, F-42023, Saint-Étienne, France
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Herrera-García A, Pérez-Mendoza M, Arellanes-Licea EDC, Gasca-Martínez D, Carmona-Castro A, Díaz-Muñoz M, Miranda-Anaya M. Obesity in male volcano mice Neotomodon alstoni affects the daily rhythm of metabolism and thermoregulation. Front Nutr 2022; 9:963804. [PMID: 35990356 PMCID: PMC9386375 DOI: 10.3389/fnut.2022.963804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 07/13/2022] [Indexed: 11/13/2022] Open
Abstract
The mouse N. alstoni spontaneously develops the condition of obesity in captivity when fed regular chow. We aim to study the differences in metabolic performance and thermoregulation between adult lean and obese male mice. The experimental approach included indirect calorimetry using metabolic cages for VO2 intake and VCO2 production. In contrast, the body temperature was measured and analyzed using intraperitoneal data loggers. It was correlated with the relative presence of UCP1 protein and its gene expression from interscapular adipose tissue (iBAT). We also explored in this tissue the relative presence of Tyrosine Hydroxylase (TH) protein, the rate-limiting enzyme for catecholamine biosynthesis present in iBAT. Results indicate that obese mice show a daily rhythm persists in estimated parameters but with differences in amplitude and profile. Obese mice presented lower body temperature, and a low caloric expenditure, together with lower VO2 intake and VCO2 than lean mice. Also, obese mice present a reduced thermoregulatory response after a cold pulse. Results are correlated with a low relative presence of TH and UCP1 protein. However, qPCR analysis of Ucp1 presents an increase in gene expression in iBAT. Histology showed a reduced amount of brown adipocytes in BAT. The aforementioned indicates that the daily rhythm in aerobic metabolism, thermoregulation, and body temperature control have reduced amplitude in obese mice Neotomodon alstoni.
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Affiliation(s)
- Andrea Herrera-García
- Unidad Multidisciplinaria de Docencia e Investigación, Facultad de Ciencias, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, Mexico
- Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Juriquilla, Querétaro, Mexico
| | - Moisés Pérez-Mendoza
- Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Juriquilla, Querétaro, Mexico
| | - Elvira del Carmen Arellanes-Licea
- Unidad Multidisciplinaria de Docencia e Investigación, Facultad de Ciencias, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, Mexico
| | - Deisy Gasca-Martínez
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, Mexico
| | - Agustín Carmona-Castro
- Unidad Multidisciplinaria de Docencia e Investigación, Facultad de Ciencias, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, Mexico
| | - Mauricio Díaz-Muñoz
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, Mexico
| | - Manuel Miranda-Anaya
- Unidad Multidisciplinaria de Docencia e Investigación, Facultad de Ciencias, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, Mexico
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Li Y, Fromme T. Uncoupling Protein 1 Does Not Produce Heat without Activation. Int J Mol Sci 2022; 23:2406. [PMID: 35269549 PMCID: PMC8910648 DOI: 10.3390/ijms23052406] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/16/2022] [Accepted: 02/18/2022] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial uncoupling protein 1 (UCP1) is the crucial mechanistic component of heat production in classical brown fat and the newly identified beige or brite fat. Thermogenesis inevitably comes at a high energetic cost and brown fat, ultimately, is an energy-wasting organ. A constrained strategy that minimizes brown fat activity unless obligate will have been favored during natural selection to safeguard metabolic thriftiness. Accordingly, UCP1 is constitutively inhibited and is inherently not leaky without activation. It follows that increasing brown adipocyte number or UCP1 abundance genetically or pharmacologically does not lead to an automatic increase in thermogenesis or subsequent metabolic consequences in the absence of a plausible route of concomitant activation. Despite its apparent obviousness, this tenet is frequently ignored. Consequently, incorrect conclusions are often drawn from increased BAT or brite/beige depot mass, e.g., predicting or causally linking beneficial metabolic effects. Here, we highlight the inherently inactive nature of UCP1, with a particular emphasis on the molecular brakes and releases of UCP1 activation under physiological conditions. These controls of UCP1 activity represent potential targets of therapeutic interventions to unlock constraints and efficiently harness the energy-expending potential of brown fat to prevent and treat obesity and associated metabolic disorders.
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Affiliation(s)
- Yongguo Li
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Gregor-Mendel-Str. 2, 85354 Freising, Germany
| | - Tobias Fromme
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Gregor-Mendel-Str. 2, 85354 Freising, Germany
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Abstract
Brown adipose tissue (BAT) was first identified by Conrad Gessner in 1551, but it was only in 1961 that it was firmly identified as a thermogenic organ. Key developments in the subsequent two decades demonstrated that: (1) BAT is quantitatively important to non-shivering thermogenesis in rodents, (2) uncoupling of oxidative phosphorylation through a mitochondrial proton conductance pathway is the central mechanism by which heat is generated, (3) uncoupling protein-1 is the critical factor regulating proton leakage in BAT mitochondria. Following pivotal studies on cafeteria-fed rats and obese ob/ob mice, BAT was then shown to have a central role in the regulation of energy balance and the etiology of obesity. The application of fluorodeoxyglucose positron emission tomography in the late 2000s confirmed that BAT is present and active in adults, resulting in renewed interest in the tissue in human energetics and obesity. Subsequent studies have demonstrated a broad metabolic role for BAT, the tissue being an important site of glucose disposal and triglyceride clearance, as well as of insulin action. BAT continues to be a potential target for the treatment of obesity and related metabolic disorders.
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Affiliation(s)
- Paul Trayhurn
- Obesity Biology Unit, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK.
- Clore Laboratory, University of Buckingham, Buckingham, UK.
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9
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Nogami M, Nishio T, Hoshi T, Toukairin Y, Arai T. Hyperketonemia as the diagnostic basis for hypothermia: An experimental study in diabetic and control mice. Leg Med (Tokyo) 2021; 52:101908. [PMID: 34062368 DOI: 10.1016/j.legalmed.2021.101908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 05/10/2021] [Accepted: 05/20/2021] [Indexed: 11/29/2022]
Abstract
Hypothermia is an important cause of death in forensic pathology. For the forensic diagnosis of hypothermia, some reports point out the possibility that hypothermia without diabetes may cause ketoacidosis. In this study, we evaluated the diagnostic value of ketoacidosis in a murine model of hypothermia, using the cold stress at 4 °C for 3 or 5 hrs in genetically diabetic (BKS.Cg-+Leprdb/+Leprdb/J) mice, compared with control (BKS.Cg- Dock7m+/Dock7m+/J) mice. The core temperature decrease was larger in diabetic mice than in control mice. We observed a novel finding that ketoacidosis assessed by elevated serum 3-hydroxybutyrate (3HB) occurs in hypothermia both in diabetic and control mice. Diabetic mice showed a prominent elevation of serum 3HB under cold stress. The protein expressions of monocarboxylate cotransporter 1 (MCT1), the channel protein used for the uptake of 3HB in skeletal muscles, showed a statistically significant decrease under cold stress for 3 hrs in control mice, indicating that the serum 3HB increase may be partially due to the decrease in the cellular uptake through the channel protein. Our results suggest the usefulness of hyperketonemia for the diagnosis of hypothermia not only in diabetic but also in non-diabetic cases.
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Affiliation(s)
- Makoto Nogami
- Department of Legal Medicine, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo 173-8605, Japan.
| | - Tadashi Nishio
- Department of Legal Medicine, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Tomoaki Hoshi
- Department of Legal Medicine, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Yoko Toukairin
- Department of Legal Medicine, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Tomomi Arai
- Department of Legal Medicine, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo 173-8605, Japan
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Mohammad H, Abutaleb NS, Dieterly AM, Lyle LT, Seleem MN. Investigating auranofin for the treatment of infected diabetic pressure ulcers in mice and dermal toxicity in pigs. Sci Rep 2021; 11:10935. [PMID: 34035383 PMCID: PMC8149385 DOI: 10.1038/s41598-021-90360-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 04/28/2021] [Indexed: 12/23/2022] Open
Abstract
Bacterial infection of pressure ulcers (PUs) are a notable source of hospitalization for individuals with diabetes. This study evaluated the safety profile and efficacy of auranofin to treat diabetic PUs infected with methicillin-resistant Staphylococcus aureus (MRSA). PUs were infected with MRSA in diabetic TALLYHO/JngJ mice and then treated with topical auranofin (2%), topical mupirocin (2%), or oral clindamycin (30 mg/kg) for four days. PUs were harvested post-treatment to enumerate bacterial burden and determine expression of cytokines/growth factors. Landrace cross pigs were exposed topically to auranofin (1%, 2%, and 3%) for 4-14 days and evaluated for signs of localized or systemic toxicity. Auranofin eradicated MRSA in PUs within four days (7.92-log10 reduction) in contrast to mupirocin (2.15-log10 reduction) and clindamycin (0.73-log10 reduction). Additionally, auranofin treatment resulted in decreased expression of pro-inflammatory cytokines and increased expression of biomarkers associated with re-epithelization of wounded tissue, confirmed with histopathologic analysis. No significant histopathologic lesions were present on porcine skin sites exposed to topical auranofin. Additionally, minimal accumulation of plasma gold and no systemic toxicity was observed in pigs exposed to topical auranofin. Auranofin appears to be a potent and safe topical agent to further investigate for treatment of mild-to-moderate MRSA-infected diabetic PUs.
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Affiliation(s)
- Haroon Mohammad
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, 625 Harrison St., West Lafayette, IN, 47907, USA
| | - Nader S Abutaleb
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, 625 Harrison St., West Lafayette, IN, 47907, USA
- Center for One Health Research, Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, 1410 Prices Fork Rd, Blacksburg, VA, 24061, USA
| | - Alexandra M Dieterly
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, 625 Harrison St., West Lafayette, IN, 47907, USA
| | - L Tiffany Lyle
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, 625 Harrison St., West Lafayette, IN, 47907, USA
- Center for Comparative Translational Research, Purdue University, 625 Harrison St., West Lafayette, IN, 47907, USA
| | - Mohamed N Seleem
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, 625 Harrison St., West Lafayette, IN, 47907, USA.
- Center for One Health Research, Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, 1410 Prices Fork Rd, Blacksburg, VA, 24061, USA.
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11
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Blondin DP, Nielsen S, Kuipers EN, Severinsen MC, Jensen VH, Miard S, Jespersen NZ, Kooijman S, Boon MR, Fortin M, Phoenix S, Frisch F, Guérin B, Turcotte ÉE, Haman F, Richard D, Picard F, Rensen PCN, Scheele C, Carpentier AC. Human Brown Adipocyte Thermogenesis Is Driven by β2-AR Stimulation. Cell Metab 2020; 32:287-300.e7. [PMID: 32755608 DOI: 10.1016/j.cmet.2020.07.005] [Citation(s) in RCA: 182] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 04/10/2020] [Accepted: 07/13/2020] [Indexed: 10/23/2022]
Abstract
Stimulation of brown adipose tissue (BAT) thermogenesis in humans has emerged as an attractive target to improve metabolic health. Pharmacological stimulations targeting the β3-adrenergic receptor (β3-AR), the adrenergic receptor believed to mediate BAT thermogenesis, have historically performed poorly in human clinical trials. Here we report that, in contrast to rodents, human BAT thermogenesis is not mediated by the stimulation of β3-AR. Oral administration of the β3-AR agonist mirabegron only elicited increases in BAT thermogenesis when ingested at the maximal allowable dose. This led to off-target binding to β1-AR and β2-AR, thereby increasing cardiovascular responses and white adipose tissue lipolysis, respectively. ADRB2 was co-expressed with UCP1 in human brown adipocytes. Pharmacological stimulation and inhibition of the β2-AR as well as knockdown of ADRB1, ADRB2, or ADRB3 in human brown adipocytes all confirmed that BAT lipolysis and thermogenesis occur through β2-AR signaling in humans (ClinicalTrials.govNCT02811289).
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Affiliation(s)
- Denis P Blondin
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada; Department of Physiology-Pharmacology, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Soren Nielsen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and Centre for Physical Activity Research, Righospitalet, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Eline N Kuipers
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, the Netherlands; Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Mai C Severinsen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and Centre for Physical Activity Research, Righospitalet, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Verena H Jensen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and Centre for Physical Activity Research, Righospitalet, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Stéphanie Miard
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Faculty of Pharmacy, Université Laval, Quebec City, QC, Canada
| | - Naja Z Jespersen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and Centre for Physical Activity Research, Righospitalet, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Sander Kooijman
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, the Netherlands; Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Mariëtte R Boon
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, the Netherlands; Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Mélanie Fortin
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Serge Phoenix
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada; Department of Nuclear Medicine and Radiobiology, Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Frédérique Frisch
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Brigitte Guérin
- Department of Nuclear Medicine and Radiobiology, Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Éric E Turcotte
- Department of Nuclear Medicine and Radiobiology, Centre d'Imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - François Haman
- Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Denis Richard
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Faculty of Pharmacy, Université Laval, Quebec City, QC, Canada
| | - Frédéric Picard
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Faculty of Pharmacy, Université Laval, Quebec City, QC, Canada
| | - Patrick C N Rensen
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, the Netherlands; Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Camilla Scheele
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and Centre for Physical Activity Research, Righospitalet, University Hospital of Copenhagen, Copenhagen, Denmark.
| | - André C Carpentier
- Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada; Department of Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada.
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12
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Is energy expenditure reduced in obese mice with mutations in the leptin/leptin receptor genes? J Nutr Sci 2020; 9:e23. [PMID: 32595967 PMCID: PMC7303803 DOI: 10.1017/jns.2020.19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 11/11/2022] Open
Abstract
Rodents with mutations in the leptin, or leptin receptor, genes have been extensively used to investigate the regulation of energy balance and the factors that underlie the development of obesity. The excess energy gain of these mutants has long been considered as being due in part to increased metabolic efficiency, consequent to reduced energy expenditure, but this view has recently been challenged. We argue, particularly though not exclusively, from data on ob/ob mice, that three lines of evidence support the proposition that reduced expenditure is important in the aetiology of obesity in leptin pathway mutants (irrespective of the genetic background): (i) milk intake is similar in suckling ob/ob and +/? mice; (ii) ob/ob mice deposit excess energy when pair-fed to the ad libitum food intake of lean siblings; (iii) in several studies mutant mice have been shown to exhibit a lower RMR ‘per animal’ at temperatures below thermoneutrality. When metabolic rate is expressed ‘per unit body weight’ (inappropriately, because of body composition differences), then it is invariably lower in the obese than the lean. It is important to differentiate the causes from the consequences of obesity. Hyperphagic, mature obese animals weighing 2–3 times their lean siblings may well have higher expenditure ‘per animal’, reflecting the costs of being larger and of enhanced obligatory diet-induced thermogenesis resulting from the increased food intake. This cannot, however, be used to inform the aetiology of their obesity.
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13
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Zhang C, He X, Sheng Y, Xu J, Yang C, Zheng S, Liu J, Li H, Ge J, Yang M, Zhai B, Xu W, Luo Y, Huang K. Allicin Regulates Energy Homeostasis through Brown Adipose Tissue. iScience 2020; 23:101113. [PMID: 32413611 PMCID: PMC7226876 DOI: 10.1016/j.isci.2020.101113] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 01/15/2020] [Accepted: 04/24/2020] [Indexed: 12/19/2022] Open
Abstract
Brown adipose tissue (BAT) is a promising potential therapeutic target for the treatment of obesity and related metabolic diseases. Allicin, a natural product in garlic, has multiple biological and pharmacological functions. However, the role of allicin in the regulation of metabolic organs, particularly BAT activation, has not been well studied. Here, we show that allicin imparts a significant effect by inhibiting body weight gain, decreasing adiposity, maintaining glucose homeostasis, improving insulin resistance, and ameliorating hepatic steatosis in obese mice. These observations strongly correlate with the activation of BAT. Notably, allicin plays a role in BAT activation, which may partly contribute to the Sirt1-PGC1α-Tfam pathway. In addition, allicin can significantly increase the succinylation levels of UCP1 in BAT by inhibiting sirt5, whereas excess allicin induces autophagy/mitophagy and mitochondrial dysfunction. Thus, our findings point to allicin as a promising therapeutic approach for the treatment of obesity and metabolic disorders. Allicin reduces adiposity and maintains glucose homeostasis Allicin activates the brown adipocytes and increases the energy expenditure Allicin enhances BAT activity partly through SIRT1-PGC1a-Tfam signaling pathway Allicin regulates mitophagy via suppressed sirt5-mediated succinylation accumulation
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Affiliation(s)
- Chuanhai Zhang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China
| | - Xiaoyun He
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China
| | - Yao Sheng
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China
| | - Jia Xu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China
| | - Cui Yang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China
| | - Shujuan Zheng
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China
| | - Junyu Liu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China
| | - Haoyu Li
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China
| | - Jianbing Ge
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China
| | - Minglan Yang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China
| | - Baiqiang Zhai
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China
| | - Wentao Xu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China
| | - Yunbo Luo
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China.
| | - Kunlun Huang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing 100083, China.
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14
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Abstract
Animals that lack the hormone leptin become grossly obese, purportedly for 2 reasons: increased food intake and decreased energy expenditure (thermogenesis). This review examines the experimental evidence for the thermogenesis component. Analysis of the data available led us to conclude that the reports indicating hypometabolism in the leptin-deficient ob/ob mice (as well as in the leptin-receptor-deficient db/db mice and fa/fa rats) derive from a misleading calculation artefact resulting from expression of energy expenditure per gram of body weight and not per intact organism. Correspondingly, the body weight-reducing effects of leptin are not augmented by enhanced thermogenesis. Congruent with this, there is no evidence that the ob/ob mouse demonstrates atrophied brown adipose tissue or diminished levels of total UCP1 mRNA or protein when the ob mutation is studied on the inbred C57BL/6 mouse background, but a reduced sympathetic nerve activity is observed. On the outbred "Aston" mouse background, brown adipose tissue atrophy is seen, but whether this is of quantitative significance for the development of obesity has not been demonstrated. We conclude that leptin is not a thermogenic hormone. Rather, leptin has effects on body temperature regulation, by opposing torpor bouts and by shifting thermoregulatory thresholds. The central pathways behind these effects are largely unexplored.
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Affiliation(s)
- Alexander W Fischer
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden.,Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Barbara Cannon
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden
| | - Jan Nedergaard
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden
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15
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Wittrisch S, Klöting N, Mörl K, Chakaroun R, Blüher M, Beck-Sickinger AG. NPY 1R-targeted peptide-mediated delivery of a dual PPARα/γ agonist to adipocytes enhances adipogenesis and prevents diabetes progression. Mol Metab 2019; 31:163-180. [PMID: 31918918 PMCID: PMC6931124 DOI: 10.1016/j.molmet.2019.11.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 10/31/2019] [Accepted: 11/10/2019] [Indexed: 12/12/2022] Open
Abstract
Objective PPARα/γ dual agonists have been in clinical development for the treatment of metabolic diseases including type 2 diabetes and dyslipidemia. However, severe adverse side effects led to complications in clinical trials. As most of the beneficial effects rely on the compound activity in adipocytes, the selective targeting of this cell type is a cutting-edge strategy to develop safe anti-diabetic drugs. The goal of this study was to strengthen the adipocyte-specific uptake of the PPARα/γ agonist tesaglitazar via NPY1R-mediated internalization. Methods NPY1R-preferring peptide tesaglitazar-[F7, P34]-NPY (tesa-NPY) was synthesized by a combination of automated SPPS and manual couplings. Following molecular and functional analyses for proof of concept, cell culture experiments were conducted to monitor the effects on adipogenesis. Mice treated with peptide drug conjugates or vehicle either by gavage or intraperitoneal injection were characterized phenotypically and metabolically. Histological analysis and transcriptional profiling of the adipose tissue were performed. Results In vitro studies revealed that the tesaglitazar-[F7, P34]-NPY conjugate selectively activates PPARγ in NPY1R-expressing cells and enhances adipocyte differentiation and adiponectin expression in adipocyte precursor cells. In vivo studies using db/db mice demonstrated that the anti-diabetic activity of the peptide conjugate is as efficient as that of systemically administered tesaglitazar. Additionally, tesa-NPY induces adipocyte differentiation in vivo. Conclusions The use of the tesaglitazar-[F7, P34]-NPY conjugate is a promising strategy to apply the beneficial PPARα/γ effects in adipocytes while potentially omitting adverse effects in other tissues. Tesaglitazar-NPY targets adipocytes via NPY1R receptor-mediated internalization. Peptide-drug conjugate is specifically delivered to NPY1R-expressing cells. Release of tesaglitazar in adipocytes activates PPARγ. Drug delivery enhances adipocyte differentiation and adiponectin expression. Peptide conjugate exhibits antidiabetic activity in vivo.
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Affiliation(s)
- Stefanie Wittrisch
- Universität Leipzig, Institute of Biochemistry, Brüderstraße 34, 04103 Leipzig, Germany
| | - Nora Klöting
- Helmholtz Institute for Metabolic, Obesity, and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Ph.-Rosenthal-Str. 27, 04103 Leipzig, Germany.
| | - Karin Mörl
- Universität Leipzig, Institute of Biochemistry, Brüderstraße 34, 04103 Leipzig, Germany
| | - Rima Chakaroun
- Helmholtz Institute for Metabolic, Obesity, and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Ph.-Rosenthal-Str. 27, 04103 Leipzig, Germany; Department of Medicine, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany
| | - Matthias Blüher
- Helmholtz Institute for Metabolic, Obesity, and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Ph.-Rosenthal-Str. 27, 04103 Leipzig, Germany; Department of Medicine, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany.
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16
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Keune JA, Branscum AJ, Wong CP, Iwaniec UT, Turner RT. Effect of Leptin Deficiency on the Skeletal Response to Hindlimb Unloading in Adult Male Mice. Sci Rep 2019; 9:9336. [PMID: 31249331 PMCID: PMC6597714 DOI: 10.1038/s41598-019-45587-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 06/06/2019] [Indexed: 12/29/2022] Open
Abstract
Based on body weight, morbidly obese leptin-deficient ob/ob mice have less bone than expected, suggesting that leptin plays a role in the skeletal response to weight bearing. To evaluate this possibility, we compared the skeletal response of wild type (WT) and ob/ob mice to hindlimb unloading (HU). Mice were individually housed at 32 °C (thermoneutral) from 4 weeks of age (rapidly growing) to 16 weeks of age (approaching skeletal maturity). Mice were then randomized into one of 4 groups (n = 10/group): (1) WT control, (2) WT HU, (3) ob/ob control, and (4) ob/ob HU and the results analyzed by 2-way ANOVA. ob/ob mice pair-fed to WT mice had normal cancellous bone volume fraction (BV/TV) in distal femur, lower femur length and total bone area, mineral content (BMC) and density (BMD), and higher cancellous bone volume fraction in lumbar vertebra (LV). HU resulted in lower BMC and BMD in total femur, and lower BV/TV in distal femur and LV in both genotypes. Cancellous bone loss in femur in both genotypes was associated with increases in osteoclast-lined bone perimeter. In summary, leptin deficiency did not attenuate HU-induced osteopenia in male mice, suggesting that leptin is not required for bone loss induced by unweighting.
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Affiliation(s)
- Jessica A. Keune
- 0000 0001 2112 1969grid.4391.fSkeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331 USA
| | - Adam J. Branscum
- 0000 0001 2112 1969grid.4391.fBiostatistics Program, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331 USA
| | - Carmen P. Wong
- 0000 0001 2112 1969grid.4391.fSkeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331 USA
| | - Urszula T. Iwaniec
- 0000 0001 2112 1969grid.4391.fSkeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331 USA ,0000 0001 2112 1969grid.4391.fCenter for Healthy Aging Research, Oregon State University, Corvallis, OR 97331 USA
| | - Russell T. Turner
- 0000 0001 2112 1969grid.4391.fSkeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331 USA ,0000 0001 2112 1969grid.4391.fCenter for Healthy Aging Research, Oregon State University, Corvallis, OR 97331 USA
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17
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Trayhurn P. Brown Adipose Tissue-A Therapeutic Target in Obesity? Front Physiol 2018; 9:1672. [PMID: 30532712 PMCID: PMC6265308 DOI: 10.3389/fphys.2018.01672] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/07/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Paul Trayhurn
- Clore Laboratory, University of Buckingham, Buckingham, United Kingdom
- Obesity Biology Unit, University of Liverpool, Liverpool, United Kingdom
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18
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Crew RC, Waddell BJ, Maloney SK, Mark PJ. Diet-induced obesity reduces core body temperature across the estrous cycle and pregnancy in the rat. Chronobiol Int 2018; 35:1077-1087. [PMID: 29659304 DOI: 10.1080/07420528.2018.1458035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Obesity during pregnancy causes adverse maternal and fetal health outcomes and programs offspring for adult-onset diseases, including cardiovascular disease. Obesity also disrupts core body temperature (Tc) regulation in nonpregnant rodents; however, it is unknown whether obesity alters normal maternal Tc adaptations to pregnancy. Since Tc is influenced by the circadian system, and both obesity and pregnancy alter circadian biology, it was hypothesized that obesity disrupts the normal rhythmic patterns of Tc before and during gestation. Obesity was induced by cafeteria (CAF) feeding in female Wistar rats for 8 weeks prior to and during gestation, whereas control (CON) animals had free access to chow. Intraperitoneal temperature loggers measured daily Tc profiles throughout the study, while maternal body composition and leptin levels were assessed near term. Daily temperature profiles were examined for rhythmic features (mesor, amplitude and acrophase) by cosine regression analysis. CAF animals exhibited increased fat mass (93%) and associated hyperleptinemia (3.2-fold increase) compared to CON animals. CAF consumption reduced the average Tc (by up to 0.29°C) across the estrous cycle and most of pregnancy; however, Tc for CAF and CON animals converged toward the end of gestation. Obesity reduced the amplitude of Tc rhythms at estrus and proestrus and on day 8 of pregnancy, but increased the amplitude at day 20 of pregnancy. Photoperiod analysis revealed that obesity reduced Tc exclusively in the light period during pre-pregnancy but only during the dark period in late gestation. In conclusion, obesity alters rhythmic Tc profiles and reduces the magnitude of the Tc decline late in rat gestation, which may have implications for maternal health and fetal development.
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Affiliation(s)
- Rachael C Crew
- a School of Human Sciences , The University of Western Australia , Perth , Australia
| | - Brendan J Waddell
- a School of Human Sciences , The University of Western Australia , Perth , Australia
| | - Shane K Maloney
- a School of Human Sciences , The University of Western Australia , Perth , Australia
| | - Peter J Mark
- a School of Human Sciences , The University of Western Australia , Perth , Australia
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19
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Bone Marrow Adipose Tissue Deficiency Increases Disuse-Induced Bone Loss in Male Mice. Sci Rep 2017; 7:46325. [PMID: 28402337 PMCID: PMC5389344 DOI: 10.1038/srep46325] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 03/16/2017] [Indexed: 12/17/2022] Open
Abstract
Bone marrow adipose tissue (MAT) is negatively associated with bone mass. Since osteoblasts and adipocytes are derived from the same precursor cells, adipocyte differentiation may occur at the expense of osteoblast differentiation. We used MAT-deficient KitW/W−v (MAT-) mice to determine if absence of MAT reduced bone loss in hindlimb-unloaded (HU) mice. Male MAT- and wild-type (WT) mice were randomly assigned to a baseline, control or HU group (n = 10 mice/group) within each genotype and HU groups unloaded for 2 weeks. Femurs were evaluated using micro-computed tomography, histomorphometry and targeted gene profiling. MAT- mice had a greater reduction in bone volume fraction after HU than did WT mice. HU MAT- mice had elevated cancellous bone formation and resorption compared to other treatment groups as well as a unique profile of differentially expressed genes. Adoptive transfer of WT bone marrow-derived hematopoietic stem cells reconstituted c-kit but not MAT in KitW/W−v mice. The MAT- WT → KitW/W−v mice lost cancellous bone following 2 weeks of HU. In summary, results from this study suggest that MAT deficiency was not protective, and was associated with exaggerated disuse-induced cancellous bone loss.
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20
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Blondin DP, Tingelstad HC, Noll C, Frisch F, Phoenix S, Guérin B, Turcotte ÉE, Richard D, Haman F, Carpentier AC. Dietary fatty acid metabolism of brown adipose tissue in cold-acclimated men. Nat Commun 2017; 8:14146. [PMID: 28134339 PMCID: PMC5290270 DOI: 10.1038/ncomms14146] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 12/02/2016] [Indexed: 12/13/2022] Open
Abstract
In rodents, brown adipose tissue (BAT) plays an important role in producing heat to defend against the cold and can metabolize large amounts of dietary fatty acids (DFA). The role of BAT in DFA metabolism in humans is unknown. Here we show that mild cold stimulation (18 °C) results in a significantly greater fractional DFA extraction by BAT relative to skeletal muscle and white adipose tissue in non-cold-acclimated men given a standard liquid meal containing the long-chain fatty acid PET tracer, 14(R,S)-[18F]-fluoro-6-thia-heptadecanoic acid (18FTHA). However, the net contribution of BAT to systemic DFA clearance is comparatively small. Despite a 4-week cold acclimation increasing BAT oxidative metabolism 2.6-fold, BAT DFA uptake does not increase further. These findings show that cold-stimulated BAT can contribute to the clearance of DFA from circulation but its contribution is not as significant as the heart, liver, skeletal muscles or white adipose tissues. Brown adipose tissue (BAT) takes up and burns fatty acids for thermogenesis in mice. Here the authors use PET to show that, in humans, cold stimulation increases BAT dietary fatty acid uptake from plasma and oxidative metabolism, although, unlike mice, human BAT takes up less fatty acids than other metabolic tissues.
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Affiliation(s)
- Denis P Blondin
- Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC, Canada J1H 5N4
| | - Hans C Tingelstad
- Faculty of Health Sciences, University of Ottawa, 125 University Pvt. Ottawa, ON, Canada K1N 6N5
| | - Christophe Noll
- Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC, Canada J1H 5N4
| | - Frédérique Frisch
- Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC, Canada J1H 5N4
| | - Serge Phoenix
- Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC, Canada J1H 5N4.,Department of Nuclear Medicine and Radiobiology, Centre d'imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC, Canada J1H 5N4
| | - Brigitte Guérin
- Department of Nuclear Medicine and Radiobiology, Centre d'imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC, Canada J1H 5N4
| | - Éric E Turcotte
- Department of Nuclear Medicine and Radiobiology, Centre d'imagerie Moléculaire de Sherbrooke, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC, Canada J1H 5N4
| | - Denis Richard
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, 2725, chemin Sainte-Foy, Québec, QC, Canada G1V 4G5
| | - François Haman
- Faculty of Health Sciences, University of Ottawa, 125 University Pvt. Ottawa, ON, Canada K1N 6N5
| | - André C Carpentier
- Department of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC, Canada J1H 5N4
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21
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Yuan X, Wei G, You Y, Huang Y, Lee HJ, Dong M, Lin J, Hu T, Zhang H, Zhang C, Zhou H, Ye R, Qi X, Zhai B, Huang W, Liu S, Xie W, Liu Q, Liu X, Cui C, Li D, Zhan J, Cheng J, Yuan Z, Jin W. Rutin ameliorates obesity through brown fat activation. FASEB J 2016; 31:333-345. [PMID: 28049156 DOI: 10.1096/fj.201600459rr] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 09/28/2016] [Indexed: 11/11/2022]
Abstract
Increasing energy expenditure through activation of brown adipose tissue (BAT) is a critical approach to treating obesity and diabetes. In this study, rutin, a natural compound extracted from mulberry and a drug used as a capillary stabilizer clinically for many years without any side effects, regulated whole-body energy metabolism by enhancing BAT activity. Rutin treatment significantly reduced adiposity, increased energy expenditure, and improved glucose homeostasis in both genetically obese (Db/Db) and diet-induced obesity (DIO) mice. Rutin also induced brown-like adipocyte (beige) formation in subcutaneous adipose tissue in both obesity mouse models. Mechanistically, we found that rutin directly bound to and stabilized SIRT1, leading to hypoacetylation of peroxisome proliferator-activated receptor γ coactivator-1α protein, which stimulated Tfam transactivation and eventually augmented the number of mitochondria and UCP1 activity in BAT. These findings reveal that rutin is a novel small molecule that activates BAT and may provide a novel therapeutic approach to the treatment of metabolic disorders.-Yuan, X., Wei, G., You, Y., Huang, Y., Lee, H. J., Dong, M., Lin, J., Hu, T., Zhang, H., Zhang, C., Zhou, H., Ye, R., Qi, X., Zhai, B., Huang, W., Liu, S., Xie, W., Liu, Q., Liu, X., Cui, C., Li, D., Zhan, J., Cheng, J., Yuan, Z., Jin, W. Rutin ameliorates obesity through brown fat activation.
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Affiliation(s)
- Xiaoxue Yuan
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,The University of the Chinese Academy of Sciences, Beijing, China
| | - Gang Wei
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,The University of the Chinese Academy of Sciences, Beijing, China
| | - Yilin You
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Yuanyuan Huang
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,The University of the Chinese Academy of Sciences, Beijing, China
| | - Hyuek Jong Lee
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Meng Dong
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,The University of the Chinese Academy of Sciences, Beijing, China
| | - Jun Lin
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,The University of the Chinese Academy of Sciences, Beijing, China
| | - Tao Hu
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,The University of the Chinese Academy of Sciences, Beijing, China
| | - Hanlin Zhang
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Chuanhai Zhang
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Huiqiao Zhou
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,The University of the Chinese Academy of Sciences, Beijing, China
| | - Rongcai Ye
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,The University of the Chinese Academy of Sciences, Beijing, China
| | - Xiaolong Qi
- The University of the Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Baiqiang Zhai
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Weidong Huang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Shunai Liu
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Wen Xie
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Qingsong Liu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, China
| | - Xiaomeng Liu
- College of Life Sciences, Zhoukou Normal University, Henan, China; and
| | - Chengbi Cui
- Key Laboratory of Natural Resources of Changbai Mountain and Functional Molecules, Ministry of Education, Yanbian University, Yanji, China
| | - Donghao Li
- Key Laboratory of Natural Resources of Changbai Mountain and Functional Molecules, Ministry of Education, Yanbian University, Yanji, China
| | - Jicheng Zhan
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Jun Cheng
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Zengqiang Yuan
- The University of the Chinese Academy of Sciences, Beijing, China; .,State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Wanzhu Jin
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China;
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22
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El Khoury NB, Gratuze M, Petry F, Papon MA, Julien C, Marcouiller F, Morin F, Nicholls SB, Calon F, Hébert SS, Marette A, Planel E. Hypothermia mediates age-dependent increase of tau phosphorylation in db/db mice. Neurobiol Dis 2016; 88:55-65. [DOI: 10.1016/j.nbd.2016.01.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 12/26/2015] [Accepted: 01/07/2016] [Indexed: 11/16/2022] Open
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23
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Of mice and men: novel insights regarding constitutive and recruitable brown adipocytes. INTERNATIONAL JOURNAL OF OBESITY SUPPLEMENTS 2015; 5:S15-20. [PMID: 27152169 DOI: 10.1038/ijosup.2015.5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 02/12/2015] [Indexed: 01/02/2023]
Abstract
Recently, there has been great attention given to the possibility of combating obesity by targeting brown fat activity or increasing differentiation of brown adipocytes in white fat depots through a process termed 'browning'. Sympathetic innervation of brown and white adipose tissues provides adrenergic input that drives thermogenesis and regulates fatty acid metabolism, as well as stimulating adipogenesis of recruitable brown adipocyte tissue (rBAT, also known as beige or brite) in white fat. Other factors acting in an endocrine or autocrine/paracrine manner in adipose tissue may also stimulate browning. There have been significant recent advances in understanding the mechanisms of increasing adipose tissue energy expenditure, as well as how brown adipocytes appear in white fat depots, including via de novo adipogenesis from tissue precursor cells. In this article, we integrate this new knowledge with a historical perspective on the discovery of 'browning'. We also provide an overview of constitutive BAT vs rBAT in mouse and human.
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24
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Intracerebroventricular administration of leptin increase physical activity but has no effect on thermogenesis in cold-acclimated rats. Sci Rep 2015; 5:11189. [PMID: 26053156 PMCID: PMC4459185 DOI: 10.1038/srep11189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 04/17/2015] [Indexed: 12/03/2022] Open
Abstract
Most small homotherms display low leptin level in response to chronic cold exposure. Cold-induced hypoleptinemia was proved to induce hyperphagia. However, it is still not clear whether hypoleptinemia regulates energy expenditure in cold condition. We try to answer this question in chronic cold-acclimated rats. Results showed that 5-day intracerebroventricular(ICV) infusion of leptin (5 μg/day) had no effects on basal and adaptive thermogenesis and uncoupling protein 1 expression. Physical activity was increased by leptin treatment. We further determined whether ghrelin could reverse the increasing effect of leptin on physical activity. Coadministration of ghrelin (1.2 μg/day) completely reversed the effect of leptin on physical activity. Collectively, this study indicated the regulation of leptin on energy expenditure during cold acclimation may be mainly mediated by physical activity but not by thermogenesis. Our study outlined behavioral role of leptin during the adaptation to cold, which adds some new knowledge to promote our understanding of cold-induced metabolic adaptation.
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25
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Long-term hyperphagia and caloric restriction caused by low- or high-density husbandry have differential effects on zebrafish postembryonic development, somatic growth, fat accumulation and reproduction. PLoS One 2015; 10:e0120776. [PMID: 25799180 PMCID: PMC4370574 DOI: 10.1371/journal.pone.0120776] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 01/29/2015] [Indexed: 12/19/2022] Open
Abstract
In recent years, the zebrafish (Danio rerio) has emerged as an alternative vertebrate model for energy homeostasis and metabolic diseases, including obesity and anorexia. It has been shown that diet-induced obesity (DIO) in zebrafish shares multiple pathophysiological features with obesity in mammals. However, a systematic and comprehensive analysis of the different pathways of energy expenditure in obese and starved fish had been missing thus far. Here, we carry out long-term ad libitum feeding (hyperphagia) and caloric restriction studies induced by low- or high-density husbandry, respectively, to investigate the impact of caloric intake on the timing of scale formation, a crucial step of postembryonic development and metamorphosis, and on somatic growth, body weight, fat storage and female reproduction. We show that all of them are positively affected by increased caloric intake, that middle-aged fish develop severe DIO, and that the body mass index (BMI) displays a strict linear correlation with whole-body triglyceride levels in adult zebrafish. Interestingly, juvenile fish are largely resistant to DIO, while BMI and triglyceride values drop in aged fish, pointing to aging-associated anorexic effects. Histological analyses further indicate that increased fat storage in white adipose tissue involves both hyperplasia and hypertrophy of adipocytes. Furthermore, in ovaries, caloric intake primarily affects the rate of oocyte growth, rather than total oocyte numbers. Finally, comparing the different pathways of energy expenditure with each other, we demonstrate that they are differentially affected by caloric restriction / high-density husbandry. In juvenile fish, scale formation is prioritized over somatic growth, while in sexually mature adults, female reproduction is prioritized over somatic growth, and somatic growth over fat storage. Our data will serve as a template for future functional studies to dissect the neuroendocrine regulators of energy homeostasis mediating differential energy allocation.
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26
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Hanssen MJW, Wierts R, Hoeks J, Gemmink A, Brans B, Mottaghy FM, Schrauwen P, van Marken Lichtenbelt WD. Glucose uptake in human brown adipose tissue is impaired upon fasting-induced insulin resistance. Diabetologia 2015; 58:586-95. [PMID: 25500952 DOI: 10.1007/s00125-014-3465-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 11/17/2014] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS Human brown adipose tissue (BAT) has recently emerged as a potential target in the treatment of type 2 diabetes, owing to its capacity to actively clear glucose from the circulation—at least upon cold exposure. The effects of insulin resistance on the capacity of human BAT to take up glucose are unknown. Prolonged fasting is known to induce insulin resistance in peripheral tissues in order to spare glucose for the brain. METHODS We studied the effect of fasting-induced insulin resistance on the capacity of BAT to take up glucose during cold exposure as well as on cold-stimulated thermogenesis. BAT glucose uptake was assessed by means of cold-stimulated dynamic 2-deoxy-2-[(18)F]fluoro-D-glucose positron emission tomography/computed tomography ([(18)F]FDG-PET/CT) imaging. RESULTS We show that a 54 h fasting period markedly decreases both cold-induced BAT glucose uptake and nonshivering thermogenesis (NST) during cold stimulation. In vivo molecular imaging and modelling revealed that the reduction of glucose uptake in BAT was due to impaired cellular glucose uptake and not due to decreased supply. Interestingly, decreased BAT glucose uptake upon fasting was related to a decrease in core temperature during cold exposure, pointing towards a role for BAT in maintaining normothermia in humans. CONCLUSIONS/INTERPRETATION Cold-stimulated glucose uptake in BAT is strongly reduced upon prolonged fasting. When cold-stimulated glucose uptake in BAT is also reduced under other insulin-resistant states, such as diabetes, cold-induced activation of BAT may not be a valid way to improve glucose clearance by BAT under such conditions. TRIAL REGISTRATION www.trialregister.nl NTR3523 FUNDING: This work was supported by the EU FP7 project DIABAT (HEALTH-F2-2011-278373 to WDvML) and by the Netherlands Organization for Scientific Research (TOP 91209037 to WDvML).
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Affiliation(s)
- Mark J W Hanssen
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre+ (MUMC+), P.O. Box 616, 6200 MD, Maastricht, the Netherlands
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27
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Kasahara Y, Tateishi Y, Hiraoka Y, Otsuka A, Mizukami H, Ozawa K, Sato K, Hidema S, Nishimori K. Role of the Oxytocin Receptor Expressed in the Rostral Medullary Raphe in Thermoregulation During Cold Conditions. Front Endocrinol (Lausanne) 2015; 6:180. [PMID: 26635729 PMCID: PMC4658403 DOI: 10.3389/fendo.2015.00180] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 11/05/2015] [Indexed: 12/02/2022] Open
Abstract
Recent papers have reported that oxytocin (Oxt) and the oxytocin receptor (Oxtr) may be involved in the regulation of food intake in mammals. We therefore suspected the Oxt/Oxtr system to be involved in energy homeostasis. In previous studies, we found a tendency toward obesity in Oxtr-deficient (Oxtr (-/-)) mice, as well as impaired thermoregulation when these mice were exposed to cold conditions. In the present study, we observed the expression of Oxtr in the rostral medullary raphe (RMR), the brain region known to control thermogenesis in brown adipose tissue (BAT). Through immunohistochemistry, we detected neurons expressing Oxtr and c-Fos in the RMR of mice exposed to cold conditions. Up to 40% of Oxtr-positive neurons in RMR were classified as glutamatergic neurons, as shown by immunostaining using anti-VGLUT3 antibody. In addition, mice with exclusive expression of Oxtr in the RMR were generated by injecting an AAV-Oxtr vector into the RMR region of Oxtr (-/-) mice. We confirmed the recovery of thermoregulatory ability in the manipulated mice during exposure to cold conditions. Moreover, mice with RMR-specific expression of Oxtr lost the typical morphological change in BAT observed in Oxtr (-/-) mice. Additionally, increased expression of the β3-adrenergic receptor gene, Adrb3, was observed in BAT. These results are the first to show the critical role of RMR Oxtr expression in thermoregulation during cold conditions.
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Affiliation(s)
- Yoshiyuki Kasahara
- Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Miyagi, Japan
- Department of Disaster Psychiatry, International Research Institute of Disaster Science, Tohoku University, Miyagi, Japan
| | - Yuko Tateishi
- Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Miyagi, Japan
| | - Yuichi Hiraoka
- Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Miyagi, Japan
| | - Ayano Otsuka
- Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Miyagi, Japan
| | - Hiroaki Mizukami
- Division of Genetic Therapeutics, Centre for Molecular Medicine, Jichi Medical University, Tochigi, Japan
| | - Keiya Ozawa
- Division of Genetic Therapeutics, Centre for Molecular Medicine, Jichi Medical University, Tochigi, Japan
| | - Keisuke Sato
- Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Miyagi, Japan
| | - Shizu Hidema
- Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Miyagi, Japan
| | - Katsuhiko Nishimori
- Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Miyagi, Japan
- *Correspondence: Katsuhiko Nishimori,
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28
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Chong ACN, Greendyk RA, Zeltser LM. Distinct networks of leptin- and insulin-sensing neurons regulate thermogenic responses to nutritional and cold challenges. Diabetes 2015; 64:137-46. [PMID: 25125486 PMCID: PMC4274810 DOI: 10.2337/db14-0567] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Defense of core body temperature (Tc) can be energetically costly; thus, it is critical that thermoregulatory circuits are modulated by signals of energy availability. Hypothalamic leptin and insulin signals relay information about energy status and are reported to promote thermogenesis, raising the possibility that they interact to direct an appropriate response to nutritional and thermal challenges. To test this idea, we used an Nkx2.1-Cre driver to generate conditional knockouts (KOs) in mice of leptin receptor (L(2.1)KO), insulin receptor (I(2.1)KO), and double KOs of both receptors (D(2.1)KO). L(2.1)KOs are hyperphagic and obese, whereas I(2.1)KOs are similar to controls. D(2.1)KOs exhibit higher body weight and adiposity than L(2.1)KOs, solely due to reduced energy expenditure. At 20-22°C, fed L(2.1)KOs maintain a lower baseline Tc than controls, which is further decreased in D(2.1)KOs. After an overnight fast, some L(2.1)KOs dramatically suppress energy expenditure and enter a torpor-like state; this behavior is markedly enhanced in D(2.1)KOs. When fasted mice are exposed to 4°C, L(2.1)KOs and D(2.1)KOs both mount a robust thermogenic response and rapidly increase Tc. These observations support the idea that neuronal populations that integrate information about energy stores to regulate the defense of Tc set points are distinct from those required to respond to a cold challenge.
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Affiliation(s)
- Angie C N Chong
- Institute of Human Nutrition, Columbia University, New York, NY Naomi Berrie Diabetes Center, Columbia University, New York, NY
| | | | - Lori M Zeltser
- Naomi Berrie Diabetes Center, Columbia University, New York, NY Department of Pathology and Cell Biology, Columbia University, New York, NY
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29
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Dodd GT, Worth AA, Nunn N, Korpal AK, Bechtold DA, Allison MB, Myers MG, Statnick MA, Luckman SM. The thermogenic effect of leptin is dependent on a distinct population of prolactin-releasing peptide neurons in the dorsomedial hypothalamus. Cell Metab 2014; 20:639-49. [PMID: 25176149 PMCID: PMC4192552 DOI: 10.1016/j.cmet.2014.07.022] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 06/06/2014] [Accepted: 07/23/2014] [Indexed: 01/05/2023]
Abstract
Leptin is a critical regulator of metabolism, which acts on brain receptors (Lepr) to reduce energy intake and increase energy expenditure. Some of the cellular pathways mediating leptin's anorectic actions are identified, but those mediating the thermogenic effects have proven more difficult to decipher. We define a population of neurons in the dorsomedial hypothalamic nucleus (DMH) containing the RFamide PrRP, which is activated by leptin. Disruption of Lepr selectively in these cells blocks thermogenic responses to leptin and causes obesity. A separate population of leptin-insensitive PrRP neurons in the brainstem is required, instead, for the satiating actions of the gut-derived hormone cholecystokinin (CCK). Global deletion of PrRP (in a loxSTOPlox-PrRP mouse) results in obesity and attenuated responses to leptin and CCK. Cre-recombinase-mediated reactivation of PrRP in brainstem rescues the anorectic actions of CCK, but reactivation in the hypothalamus is required to re-establish the thermogenic effect of leptin.
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Affiliation(s)
- Garron T Dodd
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Amy A Worth
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Nicolas Nunn
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Aaron K Korpal
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - David A Bechtold
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Margaret B Allison
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Ann Arbor, Michigan 48105, USA
| | - Martin G Myers
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Ann Arbor, Michigan 48105, USA
| | - Michael A Statnick
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN 46285, USA
| | - Simon M Luckman
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK.
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30
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Turner RT, Philbrick KA, Wong CP, Olson DA, Branscum AJ, Iwaniec UT. Morbid obesity attenuates the skeletal abnormalities associated with leptin deficiency in mice. J Endocrinol 2014; 223:M1-15. [PMID: 24990938 PMCID: PMC4161659 DOI: 10.1530/joe-14-0224] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Leptin-deficient ob/ob mice are morbidly obese and exhibit low total bone mass and mild osteopetrosis. In order to disassociate the skeletal effects of leptin deficiency from those associated with morbid obesity, we evaluated bone mass, architecture, gene expression, and indices of bone turnover in WT mice, ob/ob mice allowed to feed ad libitum (ob/ob), and ob/ob mice pair-fed equivalent to WT mice (pair-fed ob/ob). Mice were maintained at 32 °C (thermoneutral) from 6 to 18 weeks of age to minimize differences in resting energy expenditure. ob/ob mice were heavier, had more abdominal white adipose tissue (WAT), and were hyperglycemic compared with WT mice. Femur length, bone mineral content (BMC) and bone mineral density, and midshaft femur cortical thickness were lower in ob/ob mice than in WT mice. Cancellous bone volume (BV) fraction was higher but indices of bone formation and resorption were lower in ob/ob mice compared with WT mice; reduced bone resorption in ob/ob mice resulted in pathological retention of calcified cartilage. Pair-fed ob/ob mice were lighter and had lower WAT, uterine weight, and serum glucose than ob/ob mice. Similarly, femoral length, BMC, and cortical thickness were lower in pair-fed ob/ob mice compared with ob/ob mice, as were indices of cancellous bone formation and resorption. In contrast, bone marrow adiposity, calcified cartilage, and cancellous BV fraction were higher at one or more cancellous sites in pair-fed ob/ob mice compared with ob/ob mice. These findings indicate that the skeletal abnormalities caused by leptin deficiency are markedly attenuated in morbidly obese ob/ob mice.
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Affiliation(s)
- Russell T Turner
- Skeletal Biology LaboratorySchool of Biological and Population Health SciencesCenter for Healthy Aging ResearchBiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USA Skeletal Biology LaboratorySchool of Biological and Population Health SciencesCenter for Healthy Aging ResearchBiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USA
| | - Kenneth A Philbrick
- Skeletal Biology LaboratorySchool of Biological and Population Health SciencesCenter for Healthy Aging ResearchBiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USA
| | - Carmen P Wong
- Skeletal Biology LaboratorySchool of Biological and Population Health SciencesCenter for Healthy Aging ResearchBiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USA
| | - Dawn A Olson
- Skeletal Biology LaboratorySchool of Biological and Population Health SciencesCenter for Healthy Aging ResearchBiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USA
| | - Adam J Branscum
- Skeletal Biology LaboratorySchool of Biological and Population Health SciencesCenter for Healthy Aging ResearchBiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USA
| | - Urszula T Iwaniec
- Skeletal Biology LaboratorySchool of Biological and Population Health SciencesCenter for Healthy Aging ResearchBiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USA Skeletal Biology LaboratorySchool of Biological and Population Health SciencesCenter for Healthy Aging ResearchBiostatisticsSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331, USA
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Xiong WT, Gu L, Wang C, Sun HX, Liu X. Anti-hyperglycemic and hypolipidemic effects of Cistanche tubulosa in type 2 diabetic db/db mice. JOURNAL OF ETHNOPHARMACOLOGY 2013; 150:935-945. [PMID: 24095831 DOI: 10.1016/j.jep.2013.09.027] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 07/22/2013] [Accepted: 09/10/2013] [Indexed: 06/02/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The dried succulent stem of Cistanche tubulosa (Schenk) R. Wight is one component of traditional Chinese medicine prescriptions for diabetes. However, there have been no modern scientific reports to confirm this traditional claim for the Cistanche species until now. Thus, we investigated the effects of Cistanche tubulosa on glucose homeostasis and serum lipids in male BKS.Cg-Dock7(m) +/+ Lepr(db)/J (db/db) mice, a model of type 2 diabetes. MATERIALS AND METHODS The verbascoside and echinacoside contents of Cistanche tubulosa powder were evaluated using HPLC. The total phenolic content, polysaccharide content and antioxidant activity of Cistanche tubulosa powder were also evaluated. Then, different doses of Cistanche tubulosa (equivalent to 120.9, 72.6 or 24.2mg verbascoside/kg) were administered orally once daily for 45 days to male db/db mice. Age matched db/+ mice were used as normal controls. Body weight, fasting blood glucose, postprandial blood glucose and insulin tolerance test were measured during the experiment. At the time of sacrifice, blood was collected for measurement of insulin level, the homeostatic model assessment of insulin resistance (HOMA-IR), and total cholesterol, triglyceride, HDL-c, LDL-c and VLDL-c levels; liver and muscle were harvested for measurement of glycogen levels. RESULTS Cistanche tubulosa significantly suppressed the elevated fasting blood glucose and postprandial blood glucose levels, improved insulin resistance and dyslipidemia, and suppressed body weight loss in db/db mice. However, Cistanche tubulosa did not significantly affect serum insulin levels or hepatic and muscle glycogen levels. CONCLUSION This study provides scientific evidence for the traditional use of Cistanche tubulosa to treat diabetes, suggesting that Cistanche tubulosa has the potential for development into a functional food ingredient or drug to prevent hyperglycemia and treat hyperlipidemia.
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Affiliation(s)
- Wen-Ting Xiong
- Food and Health Engineering Research Center of State Education Ministry, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, PR China.
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Kasahara Y, Sato K, Takayanagi Y, Mizukami H, Ozawa K, Hidema S, So KH, Kawada T, Inoue N, Ikeda I, Roh SG, Itoi K, Nishimori K. Oxytocin receptor in the hypothalamus is sufficient to rescue normal thermoregulatory function in male oxytocin receptor knockout mice. Endocrinology 2013; 154:4305-15. [PMID: 24002032 DOI: 10.1210/en.2012-2206] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Oxytocin (OXT) and OXT receptor (OXTR) have been implicated in the regulation of energy homeostasis, but the detailed mechanism is still unclear. We recently showed late-onset obesity and impaired cold-induced thermogenesis in male OXTR knockout (Oxtr(-/-)) mice. Here we demonstrate that the OXTR in the hypothalamus has important functions in thermoregulation. Male Oxtr(-/-) mice failed to maintain their body temperatures during exposure to a cold environment. Oxtr(-/-) mice also showed decreased neuronal activation in the thermoregulatory hypothalamic region during cold exposure. Normal cold-induced thermogenesis was recovered in Oxtr(-/-) mice by restoring OXTR to the hypothalamus with an adeno-associated virus-Oxtr vector. In addition, brown adipose tissue (BAT) in Oxtr(-/-) mice contained larger lipid droplets in both 10- and 20-week-old compared with BAT from age-matched Oxtr(+/+) control mice. In BAT, the expression level of β3-adrenergic receptor at normal temperature was lower in Oxtr(-/-) mice than that in control mice. In contrast, α2A-adrenergic receptor expression level was higher in BAT from Oxtr(-/-) mice in both normal and cold temperatures. Because β3- and α2A-adrenergic receptors are known to have opposite effects on the thermoregulation, the imbalance of adrenergic receptors is suspected to affect this dysfunction in the thermoregulation. Our study is the first to demonstrate that the central OXT/OXTR system plays important roles in the regulation of body temperature homeostasis.
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Affiliation(s)
- Yoshiyuki Kasahara
- PhD, Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, Miyagi 981-8555, Japan.
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Clerte M, Baron DM, Brouckaert P, Ernande L, Raher MJ, Flynn AW, Picard MH, Bloch KD, Buys ES, Scherrer-Crosbie M. Brown adipose tissue blood flow and mass in obesity: a contrast ultrasound study in mice. J Am Soc Echocardiogr 2013; 26:1465-73. [PMID: 23993691 DOI: 10.1016/j.echo.2013.07.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Indexed: 12/31/2022]
Abstract
BACKGROUND When activated by the sympathetic nervous system, brown adipose tissue (BAT) increases energy expenditure to produce heat. Augmenting BAT mass or increasing BAT activation could potentially be used to decrease obesity. Noninvasive methods to detect and monitor BAT mass are needed. Contrast ultrasound can estimate BAT blood flow and is able to measure the perfused volume of an organ and thus its mass. The objective of this study was to evaluate whether contrast ultrasound could characterize BAT mass in two mouse models of obesity: wild-type mice fed a high-fat diet and mutant db/db mice. METHODS Contrast ultrasound of BAT (Definity 2 μL/min; 14-MHz linear probe) was performed before and after stimulation of BAT with norepinephrine (NE). BAT replenishment curves were obtained, and blood flow was estimated by the product of the curve's plateau and slope. Additionally, consecutive two-dimensional images of perfused BAT were acquired at 1-mm intervals after stimulation with NE and used to assess BAT volume and mass. RESULTS BAT blood flow increased after NE infusion in all mice studied. Blood flow response to NE was similar in wild-type mice fed either a low-fat diet or a high-fat diet. BAT blood flow was lower in db/db mice than in wild-type mice (P = .02). Contrast ultrasound-derived BAT mass was correlated with BAT mass obtained at necropsy (R(2) = 0.83, P < .001). BAT mass was higher in mice fed a high-fat diet than in those fed a low-fat diet. CONCLUSIONS Contrast ultrasound can be used to estimate BAT mass in mice when BAT vascularization is not significantly impaired. This noninvasive technique may potentially allow the serial evaluation of therapies designed to augment BAT mass.
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Affiliation(s)
- Maëva Clerte
- Cardiac Ultrasound Laboratory, Cardiology Division, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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Chechi K, Carpentier AC, Richard D. Understanding the brown adipocyte as a contributor to energy homeostasis. Trends Endocrinol Metab 2013; 24:408-20. [PMID: 23711353 DOI: 10.1016/j.tem.2013.04.002] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 04/05/2013] [Accepted: 04/13/2013] [Indexed: 11/28/2022]
Abstract
Brown adipocytes are specialized cells capable of undergoing thermogenesis, a phenomenon regulated by the sympathetic nervous system, due to the presence of uncoupling protein 1 (UCP1). The recent demonstrations of their presence in adult humans, and the discovery that brown adipocytes can be derived from distinct precursors and express specific genes depending on their anatomic location, have sparked intense interest in enhancing the current understanding of their biology and relevance to human energy homeostasis. We provide an overview of the latest advances related to the developmental origins of brown adipocytes, discuss their regulation and function in both rodents and humans, and offer a critical perspective on the relevance of brown adipocyte-mediated thermogenesis in human physiology.
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Affiliation(s)
- Kanta Chechi
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, Quebec G1V 4G5, Canada
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Ernst A, Sharma AN, Elased KM, Guest PC, Rahmoune H, Bahn S. Diabetic db/db mice exhibit central nervous system and peripheral molecular alterations as seen in neurological disorders. Transl Psychiatry 2013; 3:e263. [PMID: 23715298 PMCID: PMC3669927 DOI: 10.1038/tp.2013.42] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The db/db mouse is a widely used preclinical model in diabetes research. Recent studies have shown that these mice also display aspects of psychosis and depression-like behaviors as seen in some psychiatric disorders. Here, we have performed multiplex immunoassay and liquid chromatography mass spectrometry profiling of the plasma and brain samples from db/db and control mice to identify altered pathways, which could be related to these behavioral abnormalities. This is the first study to carry out profiling of the brain proteome in this model. Plasma from the db/db mice had increased levels of leptin and insulin, decreased levels of peptide YY, glucagon and prolactin and alterations in inflammation-related proteins, compared with control mice. Frontal cortex tissue from the db/db mice showed changes in proteins involved in energy metabolism, cellular structure and neural functioning, and the hippocampus had changes in proteins involved in the same pathways, with additional effects on cellular signalling proteins. The overlap of these findings with effects seen in type 2 diabetes, schizophrenia, major depressive disorder and Alzheimer's disease might contribute to a common endophenotype seen in metabolic and neurological disorders.
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Affiliation(s)
- A Ernst
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - A N Sharma
- Department of Pharmacology and Toxicology, Wright State University, Boonshoft School of Medicine, Dayton, OH, USA
| | - K M Elased
- Department of Pharmacology and Toxicology, Wright State University, Boonshoft School of Medicine, Dayton, OH, USA
| | - P C Guest
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - H Rahmoune
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK,Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge CB21QT, UK. E-mail: or
| | - S Bahn
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK,Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands,Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge CB21QT, UK. E-mail: or
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Isoleucine or valine deprivation stimulates fat loss via increasing energy expenditure and regulating lipid metabolism in WAT. Amino Acids 2011; 43:725-34. [DOI: 10.1007/s00726-011-1123-8] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 10/07/2011] [Indexed: 01/14/2023]
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Levi J, Gray SL, Speck M, Huynh FK, Babich SL, Gibson WT, Kieffer TJ. Acute disruption of leptin signaling in vivo leads to increased insulin levels and insulin resistance. Endocrinology 2011; 152:3385-95. [PMID: 21750049 DOI: 10.1210/en.2011-0185] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Leptin, an adipocyte-derived hormone, plays an essential role in the maintenance of normal body weight and energy expenditure, as well as glucose homeostasis. Indeed, leptin-deficient ob/ob mice are obese with profound hyperinsulinemia, insulin resistance, and often hyperglycemia. Interestingly, low doses of exogenous leptin can reverse the hyperinsulinemia and hyperglycemia in these animals without altering body weight. The hyperinsulinemia in ob/ob mice may result directly from the absence of leptin signaling in pancreatic β-cells and, in turn, contribute to both obesity and insulin resistance. Here, we acutely attenuated endogenous leptin signaling in normal mice with a polyethylene glycol (PEG)ylated mouse leptin antagonist (PEG-MLA) to determine the contribution of leptin signaling in the regulation of glucose homeostasis. PEG-MLA was either injected or continuously administered via osmotic minipumps for several days, and various metabolic parameters were assessed. PEG-MLA-treated mice had increased fasting and glucose-stimulated plasma insulin levels, decreased whole-body insulin sensitivity, elevated hepatic glucose production, and impaired insulin-mediated suppression of hepatic glucose production. Moreover, PEG-MLA treatment resulted in increased food intake and increased respiratory quotient without significantly altering energy expenditure or body composition as assessed by the lean:lipid ratio. Our findings indicate that alterations in insulin sensitivity occur before changes in the lean:lipid ratio and energy expenditure during the acute disruption of endogenous leptin signaling.
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Affiliation(s)
- Jasna Levi
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
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Devalaraja-Narashimha K, Diener AM, Padanilam BJ. Cyclophilin D deficiency prevents diet-induced obesity in mice. FEBS Lett 2011; 585:677-82. [PMID: 21276794 DOI: 10.1016/j.febslet.2011.01.031] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 01/19/2011] [Indexed: 02/03/2023]
Abstract
Mitochondrial coupling efficiency is pivotal in thermogenesis and energy homeostasis. Here we show that deletion of cyclophilin D (CypD), a key modulator of the mitochondrial permeability transition pore, demonstrated resistance to diet-induced obesity (DIO) in both male and female mice, due to increased basal metabolic rate, heat production, total energy expenditure and expenditure of fat energy, despite increased food consumption. Absorption of fatty acids is not altered between CypD(-/-) and wild-type mice. Adult CypD(-/-) developed hyperglycemia, insulin resistance and glucose intolerance albeit resistant to DIO. These data demonstrate that inhibition of CypD function could protect from HFD-IO by increasing energy expenditure in both male and female mice. Inhibition of CypD may offer a novel target to modulate metabolism.
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Affiliation(s)
- Kishor Devalaraja-Narashimha
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198-5850, USA
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Barnes MJ, Rogers RC, Van Meter MJ, Hermann GE. Co-localization of TRHR1 and LepRb receptors on neurons in the hindbrain of the rat. Brain Res 2010; 1355:70-85. [PMID: 20691166 DOI: 10.1016/j.brainres.2010.07.094] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 07/24/2010] [Accepted: 07/27/2010] [Indexed: 02/06/2023]
Abstract
We have reported a highly cooperative interaction between leptin and thyrotropin releasing hormone (TRH) in the hindbrain to generate thermogenic responses (Hermann et al., 2006) (Rogers et al., 2009). Identifying the locus in the hindbrain where leptin and TRH act synergistically to increase thermogenesis will be necessary before we can determine the mechanism(s) by which this interaction occurs. Here, we performed heat-induced epitope recovery techniques and in situ hybridization to determine if neurons or afferent fibers in the hindbrain possess both TRH type 1 receptor and long-form leptin receptor [TRHR1; LepRb, respectively]. LepRb receptors were highly expressed in the solitary nucleus [NST], dorsal motor nucleus of the vagus [DMN] and catecholaminergic neurons of the ventrolateral medulla [VLM]. All neurons that contained LepRb also contained TRHR1. Fibers in the NST and the raphe pallidus [RP] and obscurrus [RO] that possess LepRb receptors were phenotypically identified as glutamatergic type 2 fibers (vglut2). Fibers in the NST and RP that possess TRHR1 receptors were phenotypically identified as serotonergic [i.e., immunopositive for the serotonin transporter; SERT]. Co-localization of LepRb and TRHR1 was not observed on individual fibers in the hindbrain but these two fiber types co-mingle in these nuclei. These anatomical arrangements may provide a basis for the synergy between leptin and TRH to increase thermogenesis.
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Affiliation(s)
- Maria J Barnes
- Laboratory of Autonomic Neuroscience, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
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Sharma AN, Elased KM, Garrett TL, Lucot JB. Neurobehavioral deficits in db/db diabetic mice. Physiol Behav 2010; 101:381-8. [PMID: 20637218 DOI: 10.1016/j.physbeh.2010.07.002] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 07/07/2010] [Accepted: 07/08/2010] [Indexed: 01/02/2023]
Abstract
Recent clinical studies indicate neurobehavioral disturbances in type-2 diabetics. However, there is paucity of preclinical research to support this concept. The validity of db/db mouse as an animal model to study type-2 diabetes and related complications is known. The present study was designed to investigate comprehensively the db/db mouse behavior as preclinical evidence of type-2 diabetes related major neurobehavioral complications. We tested juvenile (5-6weeks) and adult (10-11weeks) db/db mice for behavioral depression in forced swim test (FST), psychosis-like symptoms using pre-pulse inhibition (PPI) test, anxiety behavior employing elevated plus maze (EPM) test, locomotor behavior and thigmotaxis using open field test and working memory deficits in Y-maze test. Both juvenile and adult group db/db mice displayed behavioral despair with increased immobility time in FST. There was an age-dependent progression of psychosis-like symptoms with disrupted PPI in adult db/db mice. In the EPM test, db/db mice were less anxious as observed by increased percent open arms time and entries. They were also hypo-locomotive as evident by a decrease in their basic and fine movements. There was no impairment of working memory in the Y-maze test in db/db mice. This is the first report of depression, psychosis-like symptoms and anxiolytic behavior of db/db mouse strain. It is tempting to speculate that this mouse strain can serve as useful preclinical model to study type-2 diabetes related neurobehavioral complications.
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Affiliation(s)
- Ajaykumar N Sharma
- Wright State University, Boonshoft School of Medicine, Department of Pharmacology and Toxicology, Dayton, OH 45435, USA
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Israel D, Chua S. Leptin receptor modulation of adiposity and fertility. Trends Endocrinol Metab 2010; 21:10-6. [PMID: 19854659 PMCID: PMC2818174 DOI: 10.1016/j.tem.2009.07.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 07/15/2009] [Accepted: 07/17/2009] [Indexed: 12/28/2022]
Abstract
The leptin receptor was discovered as a leptin binding protein, which is highly expressed in the choroid plexus. Mapping of the gene's chromosomal locations in rodents revealed that mutations in Lepr were the basis of obesity/diabetes mutations in rodents and humans. Genetic manipulations that target Lepr expression in specific neurons or hypothalamic areas have generated insights into the modes by which body composition and reproductive function are modulated by the leptin receptor. These animal models have also been instrumental in identifying diabetes susceptibility genes. In this review we discuss the evidence that supports the concept of networked functions of leptin receptor as it pertains to feeding, substrate utilization and reproduction.
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Affiliation(s)
| | - Streamson Chua
- Corresponding author Phone : 718-430-2986 Fax : 718-430-8557
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UCP1 ablation induces obesity and abolishes diet-induced thermogenesis in mice exempt from thermal stress by living at thermoneutrality. Cell Metab 2009; 9:203-9. [PMID: 19187776 DOI: 10.1016/j.cmet.2008.12.014] [Citation(s) in RCA: 1004] [Impact Index Per Article: 66.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Revised: 11/14/2008] [Accepted: 12/18/2008] [Indexed: 01/11/2023]
Abstract
As original studies of UCP1-ablated mice failed to demonstrate an obesogenic effect, alternative mechanisms for adaptive adrenergic thermogenesis have been sought. However, we demonstrate here that in C57Bl6 mice exempt from thermal stress (i.e., kept at thermoneutrality), UCP1 ablation in itself induced obesity, even in mice fed control diet, and vastly augmented diet-induced obesity (high-fat diet); i.e., the mice exhibited increased metabolic efficiency. In wild-type mice, high-fat diet increased norepinephrine-induced thermogenesis; i.e., diet-induced thermogenesis was observed, but no such effect was observed in UCP1-ablated mice, demonstrating that diet-induced thermogenesis fully emanates from UCP1 activity. We conclude that ambient temperature is qualitatively determinative for the outcome of metabolic studies, that no other protein and no other mechanism can substitute for UCP1 in mediating diet-induced adrenergic thermogenesis, and that UCP1 activity can be determinative for obesity development in mice and possibly in humans.
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Transplantation of PC1/3-Expressing alpha-cells improves glucose handling and cold tolerance in leptin-resistant mice. Mol Ther 2008; 17:191-8. [PMID: 18941442 DOI: 10.1038/mt.2008.219] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Type 2 diabetes (T2D) is characterized by elevated blood glucose levels owing to insufficient secretion and/or activity of the glucose-lowering hormone insulin. Glucagon-like peptide-1 (GLP-1) has received much attention as a new treatment for diabetes because of its multiple blood glucose-lowering effects, including glucose-dependent enhancement of insulin secretion, inhibition of gastric emptying, and promotion of the survival and growth of insulin-producing beta-cells. GLP-1, along with GLP-2 and oxyntomodulin, is produced in the intestinal L-cell via processing of proglucagon by prohormone convertase 1/3 (PC1/3), while in the pancreatic alpha-cell, coexpression of proglucagon and the alternate enzyme PC2 typically results in differential processing of proglucagon to yield glucagon. We used alginate-encapsulated alpha-cells as a model to evaluate continuous delivery of PC1/3- or PC2-derived proglucagon products. In high fat-fed and db/db mice, PC1/3-, but not PC2-expressing alpha-cells improved glucose handling and transiently lowered fasting glucose levels, suggesting that continuous delivery of PC1/3-derived proglucagon products via cell therapy may be useful for diabetes treatment. In addition, we show that long-term treatment with PC1/3-expressing, but not PC2-expressing, alpha-cells improved cold-induced thermogenesis in db/db mice, demonstrating a previously unappreciated effect of one or more PC1/3-derived alpha-cell products.
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Yamanaka M, Itakura Y, Tsuchida A, Nakagawa T, Noguchi H, Taiji M. Comparison of the antidiabetic effects of brain-derived neurotrophic factor and thiazolidinediones in obese diabetic mice. Diabetes Obes Metab 2007; 9:879-88. [PMID: 17924870 DOI: 10.1111/j.1463-1326.2006.00675.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS Brain-derived neurotrophic factor (BDNF) ameliorates glucose metabolism in obese diabetic db/db mice. The antidiabetic effect of BDNF is dependent on plasma insulin levels, and BDNF enhances insulin action by modulating insulin signalling in peripheral tissues. The aim of the study was to compare the antidiabetic effects of BDNF with those of thiazolidinediones (TZDs), which are insulin-sensitizing agents, through evaluation of the effects of BDNF and TZDs on glucose metabolism, energy expenditure, pancreatic function and hepatic steatosis in db/db mice. METHODS The effects of BDNF, pioglitazone and rosiglitazone on blood glucose concentration, body weight and pancreatic insulin and glucagon contents and the effects of BDNF and troglitazone treatment for 3 weeks on blood glucose concentration, body and liver weights and histological liver images were examined in db/db mice. Furthermore, since BDNF reduces food intake in obese hyperphagic diabetic mice, the effects of BDNF treatment for 3 weeks on blood glucose concentration, body weight, fat pad and liver weights and rectal temparature in db/db mice were compared with those of troglitazone under pair-fed conditions. RESULTS BDNF, pioglitazone and rosiglitazone all ameliorated hyperglycaemia in db/db mice, but BDNF increased the pancreatic insulin content more effectively than pioglitazone and rosiglitazone. The pancreatic glucagon content decreased with BDNF, but increased with pioglitazone and rosiglitazone compared with vehicle, and body weight and liver weight increased with troglitazone, but decreased with BDNF compared with vehicle. Histological analysis of the liver showed that BDNF treatment reduced the massive vacuolization observed with vehicle, whereas troglitazone worsened the vacuolization. Body weight, fat pad and liver weights in BDNF-treated mice were significantly lower than those in pair-fed troglitazone-treated db/db mice, and rectal temperature in BDNF-treated mice was significantly higher than that in pair-fed troglitazone-treated mice, suggesting that BDNF enhances energy expenditure. CONCLUSIONS These data suggest that compared with TZDs, BDNF potently ameliorates pancreatic dysfunction, fatty liver and energy expenditure, thereby exerting favourable antidiabetic effects in type 2 diabetic mice.
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Affiliation(s)
- M Yamanaka
- Pharmacology Research Laboratories, Drug Research Division, Dainippon Sumitomo Pharma Co., Ltd, Osaka, Japan.
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Goralski KB, McCarthy TC, Hanniman EA, Zabel BA, Butcher EC, Parlee SD, Muruganandan S, Sinal CJ. Chemerin, a novel adipokine that regulates adipogenesis and adipocyte metabolism. J Biol Chem 2007; 282:28175-88. [PMID: 17635925 DOI: 10.1074/jbc.m700793200] [Citation(s) in RCA: 601] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Obesity is an alarming primary health problem and is an independent risk factor for type II diabetes, cardiovascular diseases, and hypertension. Although the pathologic mechanisms linking obesity with these co-morbidities are most likely multifactorial, increasing evidence indicates that altered secretion of adipose-derived signaling molecules (adipokines; e.g. adiponectin, leptin, and tumor necrosis factor alpha) and local inflammatory responses are contributing factors. Chemerin (RARRES2 or TIG2) is a recently discovered chemoattractant protein that serves as a ligand for the G protein-coupled receptor CMKLR1 (ChemR23 or DEZ) and has a role in adaptive and innate immunity. Here we show an unexpected, high level expression of chemerin and its cognate receptor CMKLR1 in mouse and human adipocytes. Cultured 3T3-L1 adipocytes secrete chemerin protein, which triggers CMKLR1 signaling in adipocytes and other cell types and stimulates chemotaxis of CMKLR1-expressing cells. Adenoviral small hairpin RNA targeted knockdown of chemerin or CMKLR1 expression impairs differentiation of 3T3-L1 cells into adipocytes, reduces the expression of adipocyte genes involved in glucose and lipid homeostasis, and alters metabolic functions in mature adipocytes. We conclude that chemerin is a novel adipose-derived signaling molecule that regulates adipogenesis and adipocyte metabolism.
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Affiliation(s)
- Kerry B Goralski
- Department of Pharmacology and College of Pharmacy, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada
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Cope MB, Jumbo-Lucioni P, Walton RG, Kesterson RA, Allison DB, Nagy TR. No effect of dietary fat on short-term weight gain in mice treated with atypical antipsychotic drugs. Int J Obes (Lond) 2007; 31:1014-22. [PMID: 17224931 DOI: 10.1038/sj.ijo.0803533] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
RATIONALE Atypical antipsychotic drugs (AAD) induce significant weight gain in female C57BL/6J mice. The effect of dietary fat on weight gain and serum lipids in this model is unknown. OBJECTIVES Test the hypothesis that the obesigenic effects of these drugs are greater in the presence of a high-fat diet. METHODS Female C57BL/6J mice were treated with atypical antipsychotics for 3 weeks and fed either a low-fat or high-fat diet (4.6 vs 15.6% fat by wt). Food intake (FI), body weight (BW), body composition, and serum lipids were measured during treatment with optimized doses of olanzapine, quetiapine, and risperidone. Energy intake (EI) and feed efficiency (FE) were calculated. Group differences in change were analyzed via repeated measures analysis of variance (ANOVA). Serum lipid concentrations, EI and FE were compared using two-way ANOVA. RESULTS AAD-treated mice gained significantly more weight than controls after 3 weeks (P<0.001). Treatment and diet had significant effects on FI and EI over time (P<0.001). AAD-treated mice had significantly higher FE than controls (P<0.05); however, there was no significant drug by diet interaction (P=0.65). Risperidone low-fat mice gained significantly more absolute fat mass than placebo low-fat mice (P<0.05). All treatment groups, except quetiapine low-fat and olanzapine high-fat, gained significantly more absolute lean mass than placebo controls (P<0.05). Cholesterol levels were significantly lower in quetiapine and risperidone than placebo (P<0.05). Risperidone low-fat mice had significantly higher triglyceride levels than placebo and risperidone high-fat mice (P<0.05). CONCLUSIONS A high-fat diet does not increase AAD-induced BW gain in female mice during a 3-week treatment period.
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Affiliation(s)
- M B Cope
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL 35294-3360, USA
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Palmer G, Aurrand-Lions M, Contassot E, Talabot-Ayer D, Ducrest-Gay D, Vesin C, Chobaz-Péclat V, Busso N, Gabay C. Indirect effects of leptin receptor deficiency on lymphocyte populations and immune response in db/db mice. THE JOURNAL OF IMMUNOLOGY 2006; 177:2899-907. [PMID: 16920925 DOI: 10.4049/jimmunol.177.5.2899] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Leptin-deficient ob/ob and leptin receptor (Ob-rb)-deficient db/db mice display a marked thymic atrophy and exhibit defective immune responses. Lymphocytes express leptin receptors and leptin exerts direct effects on T cells in vitro. In addition, ob/ob and db/db mice display multiple neuroendocrine and metabolic defects, through which leptin deficiency may indirectly affect the immune system in vivo. To study the relative contributions of direct and indirect effects of leptin on the immune system in a normal environment, we generated bone marrow chimeras (BMCs) by transplantation of leptin receptor-deficient db/db, or control db/+, bone marrow cells into wild-type (WT) recipients. The size and cellularity of the thymus, as well as cellular and humoral immune responses, were similar in db/db to WT and db/+ to WT BMCs. The immune phenotype of db/db mice is thus not explained by a cell autonomous defect of db/db lymphocytes. Conversely, thymus weight and cell number were decreased in the reverse graft setting in WT to db/db BMCs, indicating that expression of the leptin receptor in the environment is important for T cell development. Finally, normal thymocyte development occurred in fetal db/db thymi transplanted into WT hosts, indicating that direct effects of leptin are not required locally in the thymic microenvironment. In conclusion, direct effects of leptin on bone marrow-derived cells and on thymic stromal cells are not necessary for T lymphocyte maturation in normal mice. In contrast, leptin receptor deficiency affects the immune system indirectly via changes in the systemic environment.
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Affiliation(s)
- Gaby Palmer
- Department of Pathology and Immunology, University of Geneva School of Medicine, Switzerland
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Högberg H, Engblom L, Ekdahl A, Lidell V, Walum E, Alberts P. Temperature dependence of O2 consumption; opposite effects of leptin and etomoxir on respiratory quotient in mice. Obesity (Silver Spring) 2006; 14:673-82. [PMID: 16741269 DOI: 10.1038/oby.2006.76] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVES The aims were to compare the temperature dependence of the metabolic rate in young ob/ob mice with that in mature ob/ob and db/db mice and to examine the effect on the metabolic substrate preference of leptin and etomoxir in ob/ob, C57BL/6J (wild-type), and db/db mice. RESEARCH METHODS AND PROCEDURES In vivo oxygen consumption and carbon dioxide production were continuously measured by indirect calorimetry, and body temperature and total locomotor activity were measured by an implanted transponder. Leptin, etomoxir, or vehicle was administered intraperitoneally. RESULTS The temperature dependence of the metabolic rate of mature ob/ob and db/db mice were similar to that in wild-type mice. In young 6-week-old ob/ob mice, the metabolic rate was almost doubled at 15 degrees C. Leptin (2 x 3 mg/kg) decreased the respiratory quotient (RQ) and carbon dioxide production but did not alter oxygen consumption, body temperature, or locomotor activity in ob/ob and C57BL/6J mice and had no effect in the db/db mice. Etomoxir (2 x 30 mg/kg) enhanced RQ and decreased oxygen consumption, carbon dioxide production, and body temperature in ob/ob, C57BL/6J, and db/db mice. Total locomotor activity was reduced in ob/ob and C57BL/6J mice. DISCUSSION In young ob/ob mice, the temperature sensitivity was enhanced compared with mature mice. Leptin and etomoxir had opposite effects on metabolic substrate preference. Leptin and lowered environmental temperature increased the relative fat oxidation as indicated by decreased RQ, possibly through activation of the sympathetic nervous system.
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Abstract
Leptin is produced primarily by adipocytes and functions in a feedback loop regulating body weight. Leptin deficiency results in severe obesity and a variety of endocrine abnormalities in animals and humans. Several studies indicated that leptin plays an important role in immune responses. It exerts protective anti-inflammatory effects in models of acute inflammation and during activation of innate immune responses. In contrast, leptin stimulates T lymphocyte responses, thus having rather a proinflammatory role in experimental models of autoimmune diseases. Clinical studies have so far yielded inconsistent results, suggesting a rather complex role for leptin in immune-mediated inflammatory conditions in humans.
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Affiliation(s)
- Eiva Bernotiene
- Department of Experimental Research, Institute of Experimental and Clinical Medicine, Vilnius University, Vilnius, Lithuania
| | - Gaby Palmer
- Division of Rheumatology, Department of Internal Medicine, University Hospital, Geneva, Switzerland
- Department of Pathology and Immunology, University of Geneva School of Medicine, Geneva, Switzerland
| | - Cem Gabay
- Division of Rheumatology, Department of Internal Medicine, University Hospital, Geneva, Switzerland
- Department of Pathology and Immunology, University of Geneva School of Medicine, Geneva, Switzerland
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Good DJ. Using Obese Mouse Models in Research: Special Considerations for IACUC Members, Animal Care Technicians, and Researchers. Lab Anim (NY) 2005; 34:30-7. [PMID: 15685190 DOI: 10.1038/laban0205-30] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2004] [Accepted: 11/09/2004] [Indexed: 11/09/2022]
Abstract
The mouse is the animal most commonly used to study the underlying causes of and treatments for obesity. The author reviews many of the issues that should be considered by all involved in research with mice expressing this phenotype, and describes some procedures exclusive to obesity research.
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Affiliation(s)
- Deborah J Good
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA.
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