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Shemery AM, Zendlo M, Kowalski J, Gorrell E, Everett S, Wagner JG, Davis AE, Koch LG, Britton SL, Mul JD, Novak CM. Reduced contextually induced muscle thermogenesis in rats with calorie restriction and lower aerobic fitness but not monogenic obesity. Temperature (Austin) 2023; 10:379-393. [PMID: 37554387 PMCID: PMC10405760 DOI: 10.1080/23328940.2023.2171669] [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: 12/01/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/29/2023] Open
Abstract
We have previously identified predator odor as a potent stimulus activating thermogenesis in skeletal muscle in rats. As this may prove relevant for energy balance and weight loss, the current study investigated whether skeletal muscle thermogenesis was altered with negative energy balance, obesity propensity seen in association with low intrinsic aerobic fitness, and monogenic obesity. First, weight loss subsequent to 3 wk of 50% calorie restriction suppressed the muscle thermogenic response to predator odor. Next, we compared rats bred based on artificial selection for intrinsic aerobic fitness - high- and low-capacity runners (HCR, LCR) - that display robust leanness and obesity propensity, respectively. Aerobically fit HCR showed enhanced predator odor-induced muscle thermogenesis relative to the less-fit LCR. This contrasted with the profound monogenic obesity displayed by rats homozygous for a loss of function mutation in Melanocortin 4 receptor (Mc4rK3a,4X/K314X rats), which showed no discernable deficit in thermogenesis. Taken together, these data imply that body size or obesity per se are not associated with deficient muscle thermogenesis. Rather, the physiological phenotype associated with polygenic obesity propensity may encompass pleiotropic mechanisms in the thermogenic pathway. Adaptive thermogenesis associated with weight loss also likely alters muscle thermogenic mechanisms.
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Affiliation(s)
- Ashley M Shemery
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Meredith Zendlo
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Jesse Kowalski
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Erin Gorrell
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Scott Everett
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Jacob G Wagner
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Ashley E Davis
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Lauren G Koch
- Department of Physiology and Pharmacology, the University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Steven L Britton
- Department of Anesthesiology, and Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Joram D Mul
- Brain Plasticity Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Amsterdam, the Netherlands
| | - Colleen M Novak
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
- Department of Biological Sciences, Kent State University, Kent, OH, USA
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2
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Martinez-Sanchez N, Sweeney O, Sidarta-Oliveira D, Caron A, Stanley SA, Domingos AI. The sympathetic nervous system in the 21st century: Neuroimmune interactions in metabolic homeostasis and obesity. Neuron 2022; 110:3597-3626. [PMID: 36327900 PMCID: PMC9986959 DOI: 10.1016/j.neuron.2022.10.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 08/23/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022]
Abstract
The sympathetic nervous system maintains metabolic homeostasis by orchestrating the activity of organs such as the pancreas, liver, and white and brown adipose tissues. From the first renderings by Thomas Willis to contemporary techniques for visualization, tracing, and functional probing of axonal arborizations within organs, our understanding of the sympathetic nervous system has started to grow beyond classical models. In the present review, we outline the evolution of these findings and provide updated neuroanatomical maps of sympathetic innervation. We offer an autonomic framework for the neuroendocrine loop of leptin action, and we discuss the role of immune cells in regulating sympathetic terminals and metabolism. We highlight potential anti-obesity therapeutic approaches that emerge from the modern appreciation of SNS as a neural network vis a vis the historical fear of sympathomimetic pharmacology, while shifting focus from post- to pre-synaptic targeting. Finally, we critically appraise the field and where it needs to go.
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Affiliation(s)
| | - Owen Sweeney
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK
| | - Davi Sidarta-Oliveira
- Physician-Scientist Graduate Program, Obesity and Comorbidities Research Center, School of Medical Sciences, University of Campinas, Campinas, Brazil
| | - Alexandre Caron
- Faculty of Pharmacy, Université Laval, Québec City, QC G1V 0A6, Canada
| | - Sarah A Stanley
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ana I Domingos
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK.
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3
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Watts CA, Haupt A, Smith J, Welch E, Malik A, Giacomino R, Walter D, Mavundza N, Shemery A, Caldwell HK, Novak CM. Measuring Skeletal Muscle Thermogenesis in Mice and Rats. J Vis Exp 2022:10.3791/64264. [PMID: 35969093 PMCID: PMC9969793 DOI: 10.3791/64264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Skeletal muscle thermogenesis provides a potential avenue for better understanding metabolic homeostasis and the mechanisms underlying energy expenditure. Surprisingly little evidence is available to link the neural, myocellular, and molecular mechanisms of thermogenesis directly to measurable changes in muscle temperature. This paper describes a method in which temperature transponders are utilized to retrieve direct measurements of mouse and rat skeletal muscle temperature. Remote transponders are surgically implanted within the muscle of mice and rats, and the animals are given time to recover. Mice and rats must then be repeatedly habituated to the testing environment and procedure. Changes in muscle temperature are measured in response to pharmacological or contextual stimuli in the home cage. Muscle temperature can also be measured during prescribed physical activity (i.e., treadmill walking at a constant speed) to factor out changes in activity as contributors to the changes in muscle temperature induced by these stimuli. This method has been successfully used to elucidate mechanisms underlying muscle thermogenic control at the level of the brain, sympathetic nervous system, and skeletal muscle. Provided are demonstrations of this success using predator odor (PO; ferret odor) as a contextual stimulus and injections of oxytocin (Oxt) as a pharmacological stimulus, where predator odor induces muscle thermogenesis, and Oxt suppresses muscle temperature. Thus, these datasets display the efficacy of this method in detecting rapid changes in muscle temperature.
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Affiliation(s)
| | - Alexandra Haupt
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Jordan Smith
- College of Public Health, Kent State University, Kent, OH, USA
| | - Emily Welch
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Aalia Malik
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Roman Giacomino
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Dinah Walter
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | | | - Ashley Shemery
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
| | - Heather K. Caldwell
- School of Biomedical Sciences, Kent State University, Kent, OH, USA,Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Colleen M. Novak
- School of Biomedical Sciences, Kent State University, Kent, OH, USA,Department of Biological Sciences, Kent State University, Kent, OH, USA
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4
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Niu J, Tong J, Blevins JE. Oxytocin as an Anti-obesity Treatment. Front Neurosci 2021; 15:743546. [PMID: 34720864 PMCID: PMC8549820 DOI: 10.3389/fnins.2021.743546] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 09/16/2021] [Indexed: 12/19/2022] Open
Abstract
Obesity is a growing health concern, as it increases risk for heart disease, hypertension, type 2 diabetes, cancer, COVID-19 related hospitalizations and mortality. However, current weight loss therapies are often associated with psychiatric or cardiovascular side effects or poor tolerability that limit their long-term use. The hypothalamic neuropeptide, oxytocin (OT), mediates a wide range of physiologic actions, which include reproductive behavior, formation of prosocial behaviors and control of body weight. We and others have shown that OT circumvents leptin resistance and elicits weight loss in diet-induced obese rodents and non-human primates by reducing both food intake and increasing energy expenditure (EE). Chronic intranasal OT also elicits promising effects on weight loss in obese humans. This review evaluates the potential use of OT as a therapeutic strategy to treat obesity in rodents, non-human primates, and humans, and identifies potential mechanisms that mediate this effect.
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Affiliation(s)
- JingJing Niu
- VA Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Puget Sound Health Care System, Seattle, WA, United States.,Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, United States
| | - Jenny Tong
- VA Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Puget Sound Health Care System, Seattle, WA, United States.,Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, United States
| | - James E Blevins
- VA Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Puget Sound Health Care System, Seattle, WA, United States.,Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, United States
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5
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Edwards MM, Nguyen HK, Dodson AD, Herbertson AJ, Wietecha TA, Wolden-Hanson T, Graham JL, Honeycutt MK, Slattery JD, O’Brien KD, Havel PJ, Blevins JE. Effects of Combined Oxytocin and Beta-3 Receptor Agonist (CL 316243) Treatment on Body Weight and Adiposity in Male Diet-Induced Obese Rats. Front Physiol 2021; 12:725912. [PMID: 34566687 PMCID: PMC8457402 DOI: 10.3389/fphys.2021.725912] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/05/2021] [Indexed: 11/13/2022] Open
Abstract
Previous studies have indicated that oxytocin (OT) reduces body weight in diet-induced obese (DIO) rodents through reductions in energy intake and increases in energy expenditure. We recently demonstrated that hindbrain [fourth ventricular (4V)] administration of OT evokes weight loss and elevates interscapular brown adipose tissue temperature (T IBAT ) in DIO rats. What remains unclear is whether OT can be used as an adjunct with other drugs that directly target beta-3 receptors in IBAT to promote BAT thermogenesis and reduce body weight in DIO rats. We hypothesized that the combined treatment of OT and the beta-3 agonist, CL 316243, would produce an additive effect to decrease body weight and adiposity in DIO rats by reducing energy intake and increasing BAT thermogenesis. We assessed the effects of 4V infusions of OT (16 nmol/day) or vehicle (VEH) in combination with daily intraperitoneal injections of CL 316243 (0.5 mg/kg) or VEH on food intake, T IBAT , body weight and body composition. OT and CL 316243 alone reduced body weight by 7.8 ± 1.3% (P < 0.05) and 9.1 ± 2.1% (P < 0.05), respectively, but the combined treatment produced more pronounced weight loss (15.5 ± 1.2%; P < 0.05) than either treatment alone. These effects were associated with decreased adiposity, adipocyte size, energy intake and increased uncoupling protein 1 (UCP-1) content in epididymal white adipose tissue (EWAT) (P < 0.05). In addition, CL 316243 alone (P < 0.05) and in combination with OT (P < 0.05) elevated T IBAT and IBAT UCP-1 content and IBAT thermogenic gene expression. These findings are consistent with the hypothesis that the combined treatment of OT and the beta-3 agonist, CL 316243, produces an additive effect to decrease body weight. The findings from the current study suggest that the effects of the combined treatment on energy intake, fat mass, adipocyte size and browning of EWAT were not additive and appear to be driven, in part, by transient changes in energy intake in response to OT or CL 316243 alone as well as CL 316243-elicited reduction of fat mass and adipocyte size and induction of browning of EWAT.
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Affiliation(s)
- Melise M. Edwards
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
| | - Ha K. Nguyen
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
| | - Andrew D. Dodson
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
| | - Adam J. Herbertson
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
| | - Tomasz A. Wietecha
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, United States
- UW Medicine Diabetes Institute, University of Washington School of Medicine, Seattle, WA, United States
| | - Tami Wolden-Hanson
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
| | - James L. Graham
- Department of Nutrition, University of California, Davis, Davis, CA, United States
| | - Mackenzie K. Honeycutt
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
| | - Jared D. Slattery
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
| | - Kevin D. O’Brien
- UW Medicine Diabetes Institute, University of Washington School of Medicine, Seattle, WA, United States
- Division of Cardiology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, United States
| | - Peter J. Havel
- Department of Nutrition, University of California, Davis, Davis, CA, United States
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - James E. Blevins
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, United States
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, United States
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6
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Edwards MM, Nguyen HK, Herbertson AJ, Dodson AD, Wietecha T, Wolden-Hanson T, Graham JL, O'Brien KD, Havel PJ, Blevins JE. Chronic hindbrain administration of oxytocin elicits weight loss in male diet-induced obese mice. Am J Physiol Regul Integr Comp Physiol 2021; 320:R471-R487. [PMID: 33470901 PMCID: PMC8238148 DOI: 10.1152/ajpregu.00294.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 01/15/2021] [Accepted: 01/16/2021] [Indexed: 02/08/2023]
Abstract
Previous studies indicate that oxytocin (OT) administration reduces body weight in high-fat diet (HFD)-induced obese (DIO) rodents through both reductions in food intake and increases in energy expenditure. We recently demonstrated that chronic hindbrain [fourth ventricular (4V)] infusions of OT evoke weight loss in DIO rats. Based on these findings, we hypothesized that chronic 4V OT would elicit weight loss in DIO mice. We assessed the effects of 4V infusions of OT (16 nmol/day) or vehicle over 28 days on body weight, food intake, and body composition. OT reduced body weight by approximately 4.5% ± 1.4% in DIO mice relative to OT pretreatment body weight (P < 0.05). These effects were associated with reduced adiposity and adipocyte size [inguinal white adipose tissue (IWAT)] (P < 0.05) and attributed, in part, to reduced energy intake (P < 0.05) at a dose that did not increase kaolin intake (P = NS). OT tended to increase uncoupling protein-1 expression in IWAT (0.05 < P < 0.1) suggesting that OT stimulates browning of WAT. To assess OT-elicited changes in brown adipose tissue (BAT) thermogenesis, we examined the effects of 4V OT on interscapular BAT temperature (TIBAT). 4V OT (1 µg) elevated TIBAT at 0.75 (P = 0.08), 1, and 1.25 h (P < 0.05) postinjection; a higher dose (5 µg) elevated TIBAT at 0.75-, 1-, 1.25-, 1.5-, 1.75- (P < 0.05), and 2-h (0.05 < P < 0.1) postinjection. Together, these findings support the hypothesis that chronic hindbrain OT treatment evokes sustained weight loss in DIO mice by reducing energy intake and increasing BAT thermogenesis at a dose that is not associated with evidence of visceral illness.
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MESH Headings
- Adipocytes, Brown/drug effects
- Adipocytes, Brown/metabolism
- Adipocytes, Brown/pathology
- Adipocytes, White/drug effects
- Adipocytes, White/metabolism
- Adipocytes, White/pathology
- Adiposity/drug effects
- Animals
- Anti-Obesity Agents/administration & dosage
- Diet, High-Fat
- Disease Models, Animal
- Eating/drug effects
- Energy Intake/drug effects
- Infusions, Intraventricular
- Leptin/blood
- Male
- Mice, Inbred C57BL
- Obesity/drug therapy
- Obesity/metabolism
- Obesity/pathology
- Obesity/physiopathology
- Oxytocin/administration & dosage
- Rhombencephalon/drug effects
- Rhombencephalon/physiopathology
- Thermogenesis/drug effects
- Uncoupling Protein 1/metabolism
- Weight Loss/drug effects
- Mice
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Affiliation(s)
- Melise M Edwards
- Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Veteran Affairs Puget Sound Health Care System, Seattle, Washington
| | - Ha K Nguyen
- Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Veteran Affairs Puget Sound Health Care System, Seattle, Washington
| | - Adam J Herbertson
- Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Veteran Affairs Puget Sound Health Care System, Seattle, Washington
| | - Andrew D Dodson
- Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Veteran Affairs Puget Sound Health Care System, Seattle, Washington
| | - Tomasz Wietecha
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington
- UW Medicine Diabetes Institute, University of Washington School of Medicine, Seattle, Washington
| | - Tami Wolden-Hanson
- Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Veteran Affairs Puget Sound Health Care System, Seattle, Washington
| | - James L Graham
- Department of Nutrition, University of California, Davis, California
| | - Kevin D O'Brien
- UW Medicine Diabetes Institute, University of Washington School of Medicine, Seattle, Washington
- Division of Cardiology, Department of Medicine, University of Washington School of Medicine, Seattle, Washington
| | - Peter J Havel
- Department of Nutrition, University of California, Davis, California
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California
| | - James E Blevins
- Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Veteran Affairs Puget Sound Health Care System, Seattle, Washington
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington
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7
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McMillan TR, Forster MAM, Short LI, Rudecki AP, Cline DL, Gray SL. Melanotan II, a melanocortin agonist, partially rescues the impaired thermogenic capacity of pituitary adenylate cyclase-activating polypeptide deficient mice. Exp Physiol 2020; 106:427-437. [PMID: 33332767 DOI: 10.1113/ep088838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 11/27/2020] [Indexed: 12/16/2022]
Abstract
NEW FINDINGS What is the central question of this study? Can chronic treatment of pituitary adenylate cyclase-activating polypeptide (PACAP) deficient mice with the melanocortin agonist melanotan II during cold acclimation rescue the impaired thermogenic capacity previously observed in PACAP deficient mice? What is the main finding and its importance? Using a genetic model of PACAP deficiency, this study provides evidence that PACAP acts upstream of the melanocortin system in regulating sympathetic nerve activity to brown adipose tissue in mice. ABSTRACT Impaired adipose tissue function in obesity, including reduced thermogenic potential, has detrimental consequences for metabolic health. Hormonal regulation of adaptive thermogenesis is being explored as a potential therapeutic target for human obesity. Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide expressed in nuclei of the hypothalamus known to regulate energy expenditure, and functional studies reveal a role for PACAP in the central regulation of thermogenesis, although mechanisms are not well understood. We hypothesized that PACAP acts upstream of the melanocortin system to regulate sympathetic nerve activity to stimulate thermogenesis. To assess this, female PACAP-/- and PACAP+/+ mice were given daily peripheral injections of a melanocortin receptor agonist, melanotan II (MTII), for 3 weeks during cold acclimation, and the effect of MTII on thermogenic capacity and adipose tissue remodelling was examined by physiological and histological analyses. MTII partially rescued the impaired thermogenic capacity in PACAP-/- mice as compared to PACAP+/+ mice as determined by measuring noradrenaline-induced metabolic rate. In addition, MTII treatment during cold acclimation corrected the previously identified deficit in lipid utilization in response to adrenergic stimulation in PACAP-/- null mice, suggesting impaired lipid mobilization may contribute to the impaired thermogenic capacity of PACAP-/- mice. Results presented here provide physiological evidence to suggest that PACAP acts upstream of melanocortin receptors to facilitate sympathetically induced mechanisms of adaptive thermogenesis in response to cold acclimation.
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Affiliation(s)
- Thecla Rae McMillan
- Northern Medical Program, University of Northern British Columbia, Prince George, British Columbia, Canada
| | - Maeghan A M Forster
- Northern Medical Program, University of Northern British Columbia, Prince George, British Columbia, Canada
| | - Landon I Short
- Northern Medical Program, University of Northern British Columbia, Prince George, British Columbia, Canada
| | - Alexander P Rudecki
- Northern Medical Program, University of Northern British Columbia, Prince George, British Columbia, Canada
| | - Daemon L Cline
- Northern Medical Program, University of Northern British Columbia, Prince George, British Columbia, Canada
| | - Sarah L Gray
- Northern Medical Program, University of Northern British Columbia, Prince George, British Columbia, Canada
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8
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Lawson EA, Olszewski PK, Weller A, Blevins JE. The role of oxytocin in regulation of appetitive behaviour, body weight and glucose homeostasis. J Neuroendocrinol 2020; 32:e12805. [PMID: 31657509 PMCID: PMC7186135 DOI: 10.1111/jne.12805] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/14/2019] [Accepted: 10/24/2019] [Indexed: 12/28/2022]
Abstract
Obesity and its associated complications have reached epidemic proportions in the USA and also worldwide, highlighting the need for new and more effective treatments. Although the neuropeptide oxytocin (OXT) is well recognised for its peripheral effects on reproductive behaviour, the release of OXT from somatodendrites and axonal terminals within the central nervous system (CNS) is also implicated in the control of energy balance. In this review, we summarise historical data highlighting the effects of exogenous OXT as a short-term regulator of food intake in a context-specific manner and the receptor populations that may mediate these effects. We also describe what is known about the physiological role of endogenous OXT in the control of energy balance and whether serum and brain levels of OXT relate to obesity on a consistent basis across animal models and humans with obesity. We describe recent data on the effectiveness of chronic CNS administration of OXT to decrease food intake and weight gain or to elicit weight loss in diet-induced obese (DIO) and genetically obese mice and rats. Of clinical importance is the finding that chronic central and peripheral OXT treatments both evoke weight loss in obese animal models with impaired leptin signalling at doses that are not associated with visceral illness, tachyphylaxis or adverse cardiovascular effects. Moreover, these results have been largely recapitulated following chronic s.c. or intranasal treatment in DIO non-human primates (rhesus monkeys) and obese humans, respectively. We also identify plausible mechanisms that contribute to the effects of OXT on body weight and glucose homeostasis in rodents, non-human primates and humans. We conclude by describing the ongoing challenges that remain before OXT-based therapeutics can be used as a long-term strategy to treat obesity in humans.
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Affiliation(s)
- Elizabeth A Lawson
- Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Pawel K Olszewski
- Faculty of Science and Engineering, University of Waikato, Hamilton, New Zealand
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, MN, USA
| | - Aron Weller
- Psychology Department and Gonda Brain Research Center, Bar Ilan University, Ramat-Gan, Israel
| | - James E Blevins
- Department of Veterans Affairs Medical Center, Office of Research and Development Medical Research Service, VA Puget Sound Health Care System, Seattle, WA, USA
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
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9
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Aguglia A, Serafini G, Solano P, Giacomini G, Conigliaro C, Salvi V, Mencacci C, Romano M, Aguglia E, Amore M. The role of seasonality and photoperiod on the lethality of suicide attempts: A case-control study. J Affect Disord 2019; 246:895-901. [PMID: 30795496 DOI: 10.1016/j.jad.2018.12.094] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 11/19/2018] [Indexed: 11/30/2022]
Abstract
BACKGROUND The risk factors related to suicidal behaviors are complex and not yet fully known. Several studies underline how suicide results from the combination of psycho-social, biological, cultural, and environmental factors. The aim of this study was to investigate the potential role of seasonality and photoperiod on high-lethality suicide attempts (HLSA) compared with low-lethality suicide attempts (LLSA) in a sample of psychiatric inpatients. METHODS After attempting suicide, subjects were admitted in the emergency/psychiatric ward of the IRCCS Ospedale Policlinico San Martino from 1st August 2013 to 31st July 2018. Socio-demographic and clinical characteristics were collected. RESULTS The sample consisted of four hundred thirty-two individuals admitted for suicide attempt. One hundred thirty-three subjects (30.8%) of the sample committed a HLSA. The HLSA group peaked in the months with a higher sunlight exposure (June and July). Bivariate correlation analyses between seasonality/photoperiod in the whole sample and HLSA were positively associated with summer and highest solar intensity period. LIMITATIONS Data were limited to a single hospital, patients' seasonal environment, meteorological variables and psychological factors. In addition, the presence of acute life-events fostering the suicidal crisis has not been investigated. CONCLUSIONS The current study provides a novel perspective on the questions surrounding the impact of seasonality and daylight exposure on lethality of suicide attempts. further studies are needed to provide deeper understandings on the delicate molecular network that links suicide behaviors, seasonality and daylight in order to develop more effective prevention and treatment strategies in the future.
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Affiliation(s)
- Andrea Aguglia
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics Maternal and Child Health, University of Genoa, Section of Psychiatry, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy.
| | - Gianluca Serafini
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics Maternal and Child Health, University of Genoa, Section of Psychiatry, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Paola Solano
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics Maternal and Child Health, University of Genoa, Section of Psychiatry, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Gabriele Giacomini
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics Maternal and Child Health, University of Genoa, Section of Psychiatry, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Claudia Conigliaro
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics Maternal and Child Health, University of Genoa, Section of Psychiatry, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Virginio Salvi
- Department of Neuroscience, ASST Fatebenefratelli Sacco, Milan, Italy
| | - Claudio Mencacci
- Department of Neuroscience, ASST Fatebenefratelli Sacco, Milan, Italy
| | - Miroslav Romano
- Department of Experimental and Clinical Medicine, Psychiatric Clinic University Hospital "Gaspare Rodolico", University of Catania, Catania, Italy
| | - Eugenio Aguglia
- Department of Experimental and Clinical Medicine, Psychiatric Clinic University Hospital "Gaspare Rodolico", University of Catania, Catania, Italy
| | - Mario Amore
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics Maternal and Child Health, University of Genoa, Section of Psychiatry, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy
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10
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Podyma B, Sun H, Wilson EA, Carlson B, Pritikin E, Gavrilova O, Weinstein LS, Chen M. The stimulatory G protein G sα is required in melanocortin 4 receptor-expressing cells for normal energy balance, thermogenesis, and glucose metabolism. J Biol Chem 2018; 293:10993-11005. [PMID: 29794140 DOI: 10.1074/jbc.ra118.003450] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 05/21/2018] [Indexed: 01/05/2023] Open
Abstract
Central melanocortin 4 receptors (MC4Rs) stimulate energy expenditure and inhibit food intake. MC4Rs activate the G protein Gsα, but whether Gsα mediates all MC4R actions has not been established. Individuals with Albright hereditary osteodystrophy (AHO), who have heterozygous Gsα-inactivating mutations, only develop obesity when the Gsα mutation is present on the maternal allele because of tissue-specific genomic imprinting. Furthermore, evidence in mice implicates Gsα imprinting within the central nervous system (CNS) in this disorder. In this study, we examined the effects of Gsα in MC4R-expressing cells on metabolic regulation. Mice with homozygous Gsα deficiency in MC4R-expressing cells (MC4RGsKO) developed significant obesity with increased food intake and decreased energy expenditure, along with impaired insulin sensitivity and cold-induced thermogenesis. Moreover, the ability of the MC4R agonist melanotan-II (MTII) to stimulate energy expenditure and to inhibit food intake was impaired in MC4RGsKO mice. MTII failed to stimulate the secretion of the anorexigenic hormone peptide YY (PYY) from enteroendocrine L cells, a physiological response mediated by MC4R-Gsα signaling, even though baseline PYY levels were elevated in these mice. In Gsα heterozygotes, mild obesity and reduced energy expenditure were present only in mice with a Gsα deletion on the maternal allele in MC4R-expressing cells, whereas food intake was unaffected. These results demonstrate that Gsα signaling in MC4R-expressing cells is required for controlling energy balance, thermogenesis, and peripheral glucose metabolism. They further indicate that Gsα imprinting in MC4R-expressing cells contributes to obesity in Gsα knockout mice and probably in individuals with Albright hereditary osteodystrophy as well.
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Affiliation(s)
| | - Hui Sun
- From the Metabolic Diseases Branch and
| | | | | | | | - Oksana Gavrilova
- Mouse Metabolism Core Laboratory, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | | | - Min Chen
- From the Metabolic Diseases Branch and
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11
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Gavini CK, Britton SL, Koch LG, Novak CM. Inherently Lean Rats Have Enhanced Activity and Skeletal Muscle Response to Central Melanocortin Receptors. Obesity (Silver Spring) 2018; 26:885-894. [PMID: 29566460 PMCID: PMC5916025 DOI: 10.1002/oby.22166] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 02/03/2018] [Accepted: 02/05/2018] [Indexed: 01/27/2023]
Abstract
OBJECTIVE Activity thermogenesis and energy expenditure (EE) are elevated in intrinsically lean rats (high-capacity runners [HCR]) and are also stimulated by melanocortin receptor activation in the ventromedial hypothalamus (VMH). This study determined whether HCR are more responsive to central modulation of activity EE compared with low-capacity runners (LCR). METHODS HCR and LCR rats received intra-VMH microinjections of melanotan II (MTII), a mixed melanocortin receptor agonist. Changes in EE, respiratory exchange ratio, activity EE, muscle heat, norepinephrine turnover, and muscle energetic modulators were compared. RESULTS HCR were significantly more responsive to intra-VMH MTII-induced changes in EE, activity EE, norepinephrine turnover to some muscle subgroups, and muscle mRNA expression of some energetic modulators. Though HCR had high muscle activity thermogenesis, limited MTII-induced modulation of muscle thermogenesis during activity was seen in LCR only. CONCLUSIONS An inherently lean, high-capacity rat phenotype showed elevated response to central melanocortin stimulation of activity EE and use of fat as fuel. This may be driven by sympathetic outflow to skeletal muscle, which was elevated after MTII. Central melanocortin receptor activation also altered skeletal muscle energetic modulators in a manner consistent with elevated EE and lowered respiratory exchange ratio.
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Affiliation(s)
- Chaitanya K. Gavini
- School of Biomedical Sciences, Kent State University, Kent, Ohio, USA
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, USA
| | - Steven L. Britton
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Lauren G. Koch
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Physiology and Pharmacology, The University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Colleen M. Novak
- School of Biomedical Sciences, Kent State University, Kent, Ohio, USA
- Department of Biological Sciences, Kent State University, Kent, Ohio, USA
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12
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Morrison SF. Efferent neural pathways for the control of brown adipose tissue thermogenesis and shivering. HANDBOOK OF CLINICAL NEUROLOGY 2018; 156:281-303. [PMID: 30454595 DOI: 10.1016/b978-0-444-63912-7.00017-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The fundamental central neural circuits for thermoregulation orchestrate behavioral and autonomic repertoires that maintain body core temperature during thermal challenges that arise from either the ambient or the internal environment. This review summarizes our understanding of the neural pathways within the fundamental thermoregulatory reflex circuitry that comprise the efferent (i.e., beyond thermosensory) control of brown adipose tissue (BAT) and shivering thermogenesis: the motor neuron systems consisting of the BAT sympathetic preganglionic neurons and BAT sympathetic ganglion cells, and the alpha- and gamma-motoneurons; the premotor neurons in the region of the rostral raphe pallidus, and the thermogenesis-promoting neurons in the dorsomedial hypothalamus/dorsal hypothalamic area. Also included are inputs to, and neurochemical modulators of, these efferent neuronal populations that could influence their activity during thermoregulatory responses. Signals of metabolic status can be particularly significant for the energy-hungry thermoeffectors for heat production.
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Affiliation(s)
- Shaun F Morrison
- Department of Neurological Surgery, Oregon Health and Science University, Portland, OR, United States.
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13
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Roberts ZS, Wolden-Hanson T, Matsen ME, Ryu V, Vaughan CH, Graham JL, Havel PJ, Chukri DW, Schwartz MW, Morton GJ, Blevins JE. Chronic hindbrain administration of oxytocin is sufficient to elicit weight loss in diet-induced obese rats. Am J Physiol Regul Integr Comp Physiol 2017; 313:R357-R371. [PMID: 28747407 DOI: 10.1152/ajpregu.00169.2017] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 06/30/2017] [Accepted: 07/02/2017] [Indexed: 02/06/2023]
Abstract
Oxytocin (OT) administration elicits weight loss in diet-induced obese (DIO) rodents, nonhuman primates, and humans by reducing energy intake and increasing energy expenditure. Although the neurocircuitry underlying these effects remains uncertain, OT neurons in the paraventricular nucleus are positioned to control both energy intake and sympathetic nervous system outflow to interscapular brown adipose tissue (BAT) through projections to the hindbrain nucleus of the solitary tract and spinal cord. The current work was undertaken to examine whether central OT increases BAT thermogenesis, whether this effect involves hindbrain OT receptors (OTRs), and whether such effects are associated with sustained weight loss following chronic administration. To assess OT-elicited changes in BAT thermogenesis, we measured the effects of intracerebroventricular administration of OT on interscapular BAT temperature in rats and mice. Because fourth ventricular (4V) infusion targets hindbrain OTRs, whereas third ventricular (3V) administration targets both forebrain and hindbrain OTRs, we compared responses to OT following chronic 3V infusion in DIO rats and mice and chronic 4V infusion in DIO rats. We report that chronic 4V infusion of OT into two distinct rat models recapitulates the effects of 3V OT to ameliorate DIO by reducing fat mass. While reduced food intake contributes to this effect, our finding that 4V OT also increases BAT thermogenesis suggests that increased energy expenditure may contribute as well. Collectively, these findings support the hypothesis that, in DIO rats, OT action in the hindbrain evokes sustained weight loss by reducing energy intake and increasing BAT thermogenesis.
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Affiliation(s)
- Zachary S Roberts
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington
| | - Tami Wolden-Hanson
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington
| | - Miles E Matsen
- University of Washington Diabetes Institute, University of Washington School of Medicine, Seattle, Washington
| | - Vitaly Ryu
- Department of Biology, Georgia State University, Atlanta, Georgia; and.,Center for Obesity Reversal, Georgia State University, Atlanta, Georgia
| | - Cheryl H Vaughan
- Department of Biology, Georgia State University, Atlanta, Georgia; and.,Center for Obesity Reversal, Georgia State University, Atlanta, Georgia
| | - James L Graham
- Departments of Nutrition and Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California
| | - Peter J Havel
- Departments of Nutrition and Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California
| | - Daniel W Chukri
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington
| | - Michael W Schwartz
- Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington.,University of Washington Diabetes Institute, University of Washington School of Medicine, Seattle, Washington
| | - Gregory J Morton
- Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington.,University of Washington Diabetes Institute, University of Washington School of Medicine, Seattle, Washington
| | - James E Blevins
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington; .,Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington
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14
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Pandit R, Beerens S, Adan RAH. Role of leptin in energy expenditure: the hypothalamic perspective. Am J Physiol Regul Integr Comp Physiol 2017; 312:R938-R947. [PMID: 28356295 DOI: 10.1152/ajpregu.00045.2016] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 03/27/2017] [Accepted: 03/28/2017] [Indexed: 01/08/2023]
Abstract
The adipocyte-derived hormone leptin is a peripheral signal that informs the brain about the metabolic status of an organism. Although traditionally viewed as an appetite-suppressing hormone, studies in the past decade have highlighted the role of leptin in energy expenditure. Leptin has been shown to increase energy expenditure in particular through its effects on the cardiovascular system and brown adipose tissue (BAT) thermogenesis via the hypothalamus. The current review summarizes the role of leptin signaling in various hypothalamic nuclei and its effects on the sympathetic nervous system to influence blood pressure, heart rate, and BAT thermogenesis. Specifically, the role of leptin signaling on three different hypothalamic nuclei, the dorsomedial hypothalamus, the ventromedial hypothalamus, and the arcuate nucleus, is reviewed. It is known that all of these brain regions influence the sympathetic nervous system activity and thereby regulate BAT thermogenesis and the cardiovascular system. Thus the current work focuses on how leptin signaling in specific neuronal populations within these hypothalamic nuclei influences certain aspects of energy expenditure.
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Affiliation(s)
- R Pandit
- Brain Center Rudolf Magnus, Department of Translational Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
| | - S Beerens
- Brain Center Rudolf Magnus, Department of Translational Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
| | - R A H Adan
- Brain Center Rudolf Magnus, Department of Translational Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
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15
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Almundarij TI, Gavini CK, Novak CM. Suppressed sympathetic outflow to skeletal muscle, muscle thermogenesis, and activity energy expenditure with calorie restriction. Physiol Rep 2017; 5:5/4/e13171. [PMID: 28242830 PMCID: PMC5328781 DOI: 10.14814/phy2.13171] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 01/29/2017] [Indexed: 12/21/2022] Open
Abstract
During weight loss, adaptive thermogenesis occurs where energy expenditure (EE) is suppressed beyond that predicted for the smaller body size. Here, we investigated the contributions of resting and nonresting EE to the reduced total EE seen after 3 weeks of 50% calorie restriction (CR) in rats, focusing on activity‐associated EE, muscle thermogenesis, and sympathetic outflow. Prolonged food restriction resulted in a 42% reduction in daily EE, through a 40% decrease in resting EE, and a 48% decline in nonresting EE. These decreases in EE were significant even when the reductions in body weight and lean mass were taken into account. Along with a decreased caloric need for low‐to‐moderate‐intensity treadmill activity with 50% CR, baseline and activity‐related muscle thermogenesis were also suppressed, though the ability to increase muscle thermogenesis above baseline levels was not compromised. When sympathetic drive was measured by assessing norepinephrine turnover (NETO), 50% CR was found to decrease NETO in three of the four muscle groups examined, whereas elevated NETO was found in white adipose tissue of food‐restricted rats. Central activation of melanocortin 4 receptors in the ventromedial hypothalamus stimulated this pathway, enhancing activity EE; this was not compromised by 50% CR. These data suggest that suppressed activity EE contributes to adaptive thermogenesis during energy restriction. This may stem from decreased sympathetic drive to skeletal muscle, increasing locomotor efficiency and reducing skeletal muscle thermogenesis. The capacity to increase activity EE in response to central stimuli is retained, however, presenting a potential target for preventing weight regain.
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Affiliation(s)
- Tariq I Almundarij
- College of Agriculture and Veterinary Medicine, Al Qassim University, Buraydah, Al-Qassim Province, Saudi Arabia.,Department of Biological Sciences, Kent State University, Kent, Ohio
| | - Chaitanya K Gavini
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois.,School of Biomedical Sciences, Kent State University, Kent, Ohio
| | - Colleen M Novak
- Department of Biological Sciences, Kent State University, Kent, Ohio .,School of Biomedical Sciences, Kent State University, Kent, Ohio
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16
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Conceição EPS, Moura EG, Oliveira E, Guarda DS, Figueiredo MS, Quitete FT, Calvino C, Miranda RA, Mathias PCF, Manhães AC, Lisboa PC. Dietary calcium supplementation in adult rats reverts brown adipose tissue dysfunction programmed by postnatal early overfeeding. J Nutr Biochem 2017; 39:117-125. [DOI: 10.1016/j.jnutbio.2016.09.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 07/05/2016] [Accepted: 09/02/2016] [Indexed: 11/28/2022]
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17
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Nguyen NLT, Barr CL, Ryu V, Cao Q, Xue B, Bartness TJ. Separate and shared sympathetic outflow to white and brown fat coordinately regulates thermoregulation and beige adipocyte recruitment. Am J Physiol Regul Integr Comp Physiol 2016; 312:R132-R145. [PMID: 27881398 DOI: 10.1152/ajpregu.00344.2016] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/14/2016] [Accepted: 11/05/2016] [Indexed: 11/22/2022]
Abstract
White adipose tissue (WAT) and brown adipose tissue (BAT) are innervated and regulated by the sympathetic nervous system (SNS). It is not clear, however, whether there are shared or separate central SNS outflows to WAT and BAT that regulate their function. We injected two isogenic strains of pseudorabies virus, a retrograde transneuronal viral tract tracer, with unique fluorescent reporters into interscapular BAT (IBAT) and inguinal WAT (IWAT) of the same Siberian hamsters to define SNS pathways to both. To test the functional importance of SNS coordinated control of BAT and WAT, we exposed hamsters with denervated SNS nerves to IBAT to 4°C for 16-24 h and measured core and fat temperatures and norepinephrine turnover (NETO) and uncoupling protein 1 (UCP1) expression in fat tissues. Overall, there were more SNS neurons innervating IBAT than IWAT across the neuroaxis. However, there was a greater percentage of singly labeled IWAT neurons in midbrain reticular nuclei than singly labeled IBAT neurons. The hindbrain had ~30-40% of doubly labeled neurons while the forebrain had ~25% suggesting shared SNS circuitry to BAT and WAT across the brain. The raphe nucleus, a key region in thermoregulation, had ~40% doubly labeled neurons. Hamsters with IBAT SNS denervation maintained core body temperature during acute cold challenge and had increased beige adipocyte formation in IWAT. They also had increased IWAT NETO, temperature, and UCP1 expression compared with intact hamsters. These data provide strong neuroanatomical and functional evidence of WAT and BAT SNS cross talk for thermoregulation and beige adipocyte formation.
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Affiliation(s)
- Ngoc Ly T Nguyen
- Department of Biology, Georgia State University, Atlanta, Georgia.,Center for Obesity Reversal, Georgia State University, Atlanta, Georgia; and
| | - Candace L Barr
- Neuroscience Institute, Georgia State University, Atlanta, Georgia
| | - Vitaly Ryu
- Department of Biology, Georgia State University, Atlanta, Georgia.,Center for Obesity Reversal, Georgia State University, Atlanta, Georgia; and
| | - Qiang Cao
- Department of Biology, Georgia State University, Atlanta, Georgia.,Center for Obesity Reversal, Georgia State University, Atlanta, Georgia; and
| | - Bingzhong Xue
- Department of Biology, Georgia State University, Atlanta, Georgia; .,Center for Obesity Reversal, Georgia State University, Atlanta, Georgia; and.,Neuroscience Institute, Georgia State University, Atlanta, Georgia
| | - Timothy J Bartness
- Department of Biology, Georgia State University, Atlanta, Georgia.,Center for Obesity Reversal, Georgia State University, Atlanta, Georgia; and.,Neuroscience Institute, Georgia State University, Atlanta, Georgia
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18
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Gavini CK, Jones WC, Novak CM. Ventromedial hypothalamic melanocortin receptor activation: regulation of activity energy expenditure and skeletal muscle thermogenesis. J Physiol 2016; 594:5285-301. [PMID: 27126579 PMCID: PMC5023712 DOI: 10.1113/jp272352] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 04/25/2016] [Indexed: 01/13/2023] Open
Abstract
KEY POINTS The ventromedial hypothalamus (VMH) and the central melanocortin system both play vital roles in regulating energy balance by modulating energy intake and utilization. Recent evidence suggests that activation of the VMH alters skeletal muscle metabolism. We show that intra-VMH melanocortin receptor activation increases energy expenditure and physical activity, switches fuel utilization to fats, and lowers work efficiency such that excess calories are dissipated by skeletal muscle as heat. We also show that intra-VMH melanocortin receptor activation increases sympathetic nervous system outflow to skeletal muscle. Intra-VMH melanocortin receptor activation also induced significant changes in the expression of mediators of energy expenditure in muscle. These results support the role of melanocortin receptors in the VMH in the modulation of skeletal muscle metabolism. ABSTRACT The ventromedial hypothalamus (VMH) and the brain melanocortin system both play vital roles in increasing energy expenditure (EE) and physical activity, decreasing appetite and modulating sympathetic nervous system (SNS) outflow. Because of recent evidence showing that VMH activation modulates skeletal muscle metabolism, we propose the existence of an axis between the VMH and skeletal muscle, modulated by brain melanocortins, modelled on the brain control of brown adipose tissue. Activation of melanocortin receptors in the VMH of rats using a non-specific agonist melanotan II (MTII), compared to vehicle, increased oxygen consumption and EE and decreased the respiratory exchange ratio. Intra-VMH MTII enhanced activity-related EE even when activity levels were held constant. MTII treatment increased gastrocnemius muscle heat dissipation during controlled activity, as well as in the home cage. Compared to vehicle-treated rats, rats with intra-VMH melanocortin receptor activation had higher skeletal muscle norepinephrine turnover, indicating an increased SNS drive to muscle. Lastly, intra-VMH MTII induced mRNA expression of muscle energetic mediators, whereas short-term changes at the protein level were primarily limited to phosphorylation events. These results support the hypothesis that melanocortin peptides act in the VMH to increase EE by lowering the economy of activity via the enhanced expression of mediators of EE in the periphery including skeletal muscle. The data are consistent with the role of melanocortins in the VMH in the modulation of skeletal muscle metabolism.
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MESH Headings
- Adipose Tissue, Brown/drug effects
- Adipose Tissue, Brown/metabolism
- Adipose Tissue, Brown/physiology
- Adipose Tissue, White/drug effects
- Adipose Tissue, White/metabolism
- Adipose Tissue, White/physiology
- Animals
- Energy Metabolism
- Hypothalamus/physiology
- Liver/drug effects
- Liver/metabolism
- Liver/physiology
- Male
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/physiology
- Norepinephrine/metabolism
- Peptides, Cyclic/pharmacology
- Physical Conditioning, Animal
- Rats, Sprague-Dawley
- Receptors, Melanocortin/agonists
- Receptors, Melanocortin/physiology
- Thermogenesis
- alpha-MSH/analogs & derivatives
- alpha-MSH/pharmacology
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Affiliation(s)
- Chaitanya K Gavini
- School of Biomedical Sciences, Kent State University, Kent, OH, USA.
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA.
| | - William C Jones
- Department of Exercise Science/Physiology, College of Education, Health, and Human Services, Kent State University, Kent, OH, USA
| | - Colleen M Novak
- School of Biomedical Sciences, Kent State University, Kent, OH, USA
- Department of Biological Sciences, Kent State University, Kent, OH, USA
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19
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Lipolysis sensation by white fat afferent nerves triggers brown fat thermogenesis. Mol Metab 2016; 5:626-634. [PMID: 27656400 PMCID: PMC5021673 DOI: 10.1016/j.molmet.2016.06.013] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 06/24/2016] [Accepted: 06/26/2016] [Indexed: 01/31/2023] Open
Abstract
Objective Metabolic challenges, such as a cold environment, stimulate sympathetic neural efferent activity to white adipose tissue (WAT) to drive lipolysis, thereby increasing the availability of free fatty acids as one source of fuel for brown adipose tissue (BAT) thermogenesis. WAT is also innervated by sensory nerve fibers that network to metabolic brain areas; moreover, activation of these afferents is reported to increase sympathetic nervous system outflow. However, the endogenous stimuli sufficient to drive WAT afferents during metabolic challenges as well as their functional relation to BAT thermogenesis remain unknown. Method We tested if local WAT lipolysis directly activates WAT afferent nerves, and then assessed whether this WAT sensory signal affected BAT thermogenesis in Siberian hamsters (Phodopus sungorus). Results 2-deoxyglucose, a sympathetic nervous system stimulant, caused β-adrenergic receptor dependent increases in inguinal WAT (IWAT) afferent neurophysiological activity. In addition, direct IWAT injections of the β3-AR agonist CL316,243 dose-dependently increased: 1) phosphorylation of IWAT hormone sensitive lipase, an indicator of SNS-stimulated lipolysis, 2) expression of the neuronal activation marker c-Fos in dorsal root ganglion neurons receiving sensory input from IWAT, and 3) IWAT afferent neurophysiological activity, an increase blocked by antilipolytic agent 3,5-dimethylpyrazole. Finally, we demonstrated that IWAT afferent activation by lipolysis triggers interscapular BAT thermogenesis through a neural link between these two tissues. Conclusions These data suggest IWAT lipolysis activates local IWAT afferents triggering a neural circuit from WAT to BAT that acutely induces BAT thermogenesis. Glucoprivation-induced lipolysis activates sensory nerves from white fat via β-adrenoreceptors. Lipolysis sensation by local afferent nerves innervating white fat is proposed. Lipid products of lipolysis are sufficient to activate sensory nerves from white fat. Stimulation of white fat afferents by lipolysis increases brown fat temperature. Findings illustrate functional neural connectivity between white and brown fat.
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20
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Abstract
The second messenger cyclic guanosine monophosphate (cGMP) is a key mediator in physiological processes such as vascular tone, and its essential involvement in pathways regulating metabolism has been recognized in recent years. Here, we focus on the fundamental role of cGMP in brown adipose tissue (BAT) differentiation and function. In contrast to white adipose tissue (WAT), which stores energy in the form of lipids, BAT consumes energy stored in lipids to generate heat. This so-called non-shivering thermogenesis takes place in BAT mitochondria, which express the specific uncoupling protein 1 (UCP1). The energy combusting properties of BAT render it a promising target in antiobesity strategies in which BAT could burn the surplus energy that has accumulated in obese and overweight individuals. cGMP is generated by guanylyl cyclases upon activation by nitric oxide or natriuretic peptides. It affects several downstream molecules including cGMP-receptor proteins such as cGMP-dependent protein kinase and is degraded by phosphodiesterases. The cGMP pathway contains several signaling molecules that can increase cGMP signaling, resulting in activation and recruitment of brown adipocytes, and hence can enhance the energy combusting features of BAT. In this review we highlight recent results showing the physiological significance of cGMP signaling in BAT, as well as pharmacological options targeting cGMP signaling that bear a high potential to become BAT-centered therapies for the treatment of obesity.
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21
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Melanocortin-4 receptor-regulated energy homeostasis. Nat Neurosci 2016; 19:206-19. [PMID: 26814590 DOI: 10.1038/nn.4202] [Citation(s) in RCA: 215] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 11/13/2015] [Indexed: 12/11/2022]
Abstract
The melanocortin system provides a conceptual blueprint for the central control of energetic state. Defined by four principal molecular components--two antagonistically acting ligands and two cognate receptors--this phylogenetically conserved system serves as a prototype for hierarchical energy balance regulation. Over the last decade the application of conditional genetic techniques has facilitated the neuroanatomical dissection of the melanocortinergic network and identified the specific neural substrates and circuits that underscore the regulation of feeding behavior, energy expenditure, glucose homeostasis and autonomic outflow. In this regard, the melanocortin-4 receptor is a critical coordinator of mammalian energy homeostasis and body weight. Drawing on recent advances in neuroscience and genetic technologies, we consider the structure and function of the melanocortin-4 receptor circuitry and its role in energy homeostasis.
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22
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Kooijman S, van den Heuvel JK, Rensen PCN. Neuronal Control of Brown Fat Activity. Trends Endocrinol Metab 2015; 26:657-668. [PMID: 26482876 DOI: 10.1016/j.tem.2015.09.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/18/2015] [Accepted: 09/18/2015] [Indexed: 12/25/2022]
Abstract
Brown adipose tissue (BAT) activation reduces body fat and metabolic disorders by the enhanced combustion of lipids and glucose into heat. The thermogenic activity of brown adipocytes is primarily driven by the sympathetic nervous system (SNS) and controlled by the brain. In this review, we present recent advances in understanding how cues, such as temperature, light, and proteins, modulate the activity of brown fat by acting on the various hypothalamic nuclei. Given that activated BAT has a high capacity to take up and burn fatty acids (FAs) and glucose, pharmacological stimulation of brown fat in humans by either targeting the hypothalamus or mimicking outflow of the sympathetic nervous system might help improve glucose metabolism and insulin sensitivity, and also lower body fat.
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Affiliation(s)
- Sander Kooijman
- Department of Medicine, Division of Endocrinology, and Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, the Netherlands
| | - José K van den Heuvel
- Department of Medicine, Division of Endocrinology, and Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, the Netherlands
| | - Patrick C N Rensen
- Department of Medicine, Division of Endocrinology, and Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, the Netherlands.
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Bartness TJ, Garretson JT. Editorial on Ding et al. 'Adipose afferent reflex responses to insulin is mediated by melanocortin 4 type receptors in the paraventricular nucleus in insulin resistance rats'. Acta Physiol (Oxf) 2015; 214:432-5. [PMID: 26086720 DOI: 10.1111/apha.12541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- T J Bartness
- Department of Biology and Center for Obesity Reversal, Georgia State University, Atlanta, GA, USA.
| | - J T Garretson
- Department of Biology and Center for Obesity Reversal, Georgia State University, Atlanta, GA, USA
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24
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Abstract
Thermogenesis, the production of heat energy, in brown adipose tissue is a significant component of the homeostatic repertoire to maintain body temperature during the challenge of low environmental temperature in many species from mouse to man and plays a key role in elevating body temperature during the febrile response to infection. The sympathetic neural outflow determining brown adipose tissue (BAT) thermogenesis is regulated by neural networks in the CNS which increase BAT sympathetic nerve activity in response to cutaneous and deep body thermoreceptor signals. Many behavioral states, including wakefulness, immunologic responses, and stress, are characterized by elevations in core body temperature to which central command-driven BAT activation makes a significant contribution. Since energy consumption during BAT thermogenesis involves oxidation of lipid and glucose fuel molecules, the CNS network driving cold-defensive and behavioral state-related BAT activation is strongly influenced by signals reflecting the short- and long-term availability of the fuel molecules essential for BAT metabolism and, in turn, the regulation of BAT thermogenesis in response to metabolic signals can contribute to energy balance, regulation of body adipose stores and glucose utilization. This review summarizes our understanding of the functional organization and neurochemical influences within the CNS networks that modulate the level of BAT sympathetic nerve activity to produce the thermoregulatory and metabolic alterations in BAT thermogenesis and BAT energy expenditure that contribute to overall energy homeostasis and the autonomic support of behavior.
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Affiliation(s)
- Shaun F Morrison
- Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon
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25
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Blevins JE, Baskin DG. Translational and therapeutic potential of oxytocin as an anti-obesity strategy: Insights from rodents, nonhuman primates and humans. Physiol Behav 2015; 152:438-49. [PMID: 26013577 DOI: 10.1016/j.physbeh.2015.05.023] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 05/19/2015] [Accepted: 05/21/2015] [Indexed: 12/15/2022]
Abstract
The fact that more than 78 million adults in the US are considered overweight or obese highlights the need to develop new, effective strategies to treat obesity and its associated complications, including type 2 diabetes, kidney disease and cardiovascular disease. While the neurohypophyseal peptide oxytocin (OT) is well recognized for its peripheral effects to stimulate uterine contraction during parturition and milk ejection during lactation, release of OT within the brain is implicated in prosocial behaviors and in the regulation of energy balance. Previous findings indicate that chronic administration of OT decreases food intake and weight gain or elicits weight loss in diet-induced obese (DIO) mice and rats. Furthermore, chronic systemic treatment with OT largely reproduces the effects of central administration to reduce weight gain in DIO and genetically obese rodents at doses that do not appear to result in tolerance. These findings have now been recently extended to more translational models of obesity showing that chronic subcutaneous or intranasal OT treatment is sufficient to elicit body weight loss in DIO nonhuman primates and pre-diabetic obese humans. This review assesses the potential use of OT as a therapeutic strategy for treatment of obesity in rodents, nonhuman primates, and humans, and identifies potential mechanisms that mediate this effect.
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Affiliation(s)
- James E Blevins
- VA Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA; Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
| | - Denis G Baskin
- VA Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA; Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
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26
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Abstract
Brown adipose tissue (BAT) is an important source of thermogenesis which is nearly exclusively dependent on its sympathetic nervous system (SNS) innervation. We previously demonstrated the SNS outflow from brain to BAT using the retrograde SNS-specific transneuronal viral tract tracer, pseudorabies virus (PRV152) and demonstrated the sensory system (SS) inflow from BAT to brain using the anterograde SS-specific transneuronal viral tract tracer, H129 strain of herpes simplex virus-1. Several brain areas were part of both the SNS outflow to, and receive SS inflow from, interscapular BAT (IBAT) in these separate studies suggesting SNS-SS feedback loops. Therefore, we tested whether individual neurons participated in SNS-SS crosstalk by injecting both PRV152 and H129 into IBAT of Siberian hamsters. To define which dorsal root ganglia (DRG) are activated by BAT SNS stimulation, indicated by c-Fos immunoreactivity (IR), we prelabeled IBAT DRG innervating neurons by injecting the retrograde tracer Fast Blue (FB) followed 1 week later by intra-BAT injections of the specific β3-adrenoceptor agonist CL316,243 in one pad and the vehicle in the contralateral pad. There were PRV152+H129 dually infected neurons across the neuroaxis with highest densities in the raphe pallidus nucleus, nucleus of the solitary tract, periaqueductal gray, hypothalamic paraventricular nucleus, and medial preoptic area, sites strongly implicated in the control of BAT thermogenesis. CL316,243 significantly increased IBAT temperature, afferent nerve activity, and c-Fos-IR in C2-C4 DRG neurons ipsilateral to the CL316,243 injections versus the contralateral side. The neuroanatomical reality of the SNS-SS feedback loops suggests coordinated and/or multiple redundant control of BAT thermogenesis.
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27
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Evaluation of the synuclein-γ (SNCG) gene as a PPARγ target in murine adipocytes, dorsal root ganglia somatosensory neurons, and human adipose tissue. PLoS One 2015; 10:e0115830. [PMID: 25756178 PMCID: PMC4355072 DOI: 10.1371/journal.pone.0115830] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 12/02/2014] [Indexed: 11/19/2022] Open
Abstract
Recent evidence in adipocytes points to a role for synuclein-γ in metabolism and lipid droplet dynamics, but interestingly this factor is also robustly expressed in peripheral neurons. Specific regulation of the synuclein-γ gene (Sncg) by PPARγ requires further evaluation, especially in peripheral neurons, prompting us to test if Sncg is a bona fide PPARγ target in murine adipocytes and peripheral somatosensory neurons derived from the dorsal root ganglia (DRG). Sncg mRNA was decreased in 3T3-L1 adipocytes (~68%) by rosiglitazone, and this effect was diminished by the PPARγ antagonist T0070907. Chromatin immunoprecipitation experiments confirmed PPARγ protein binding at two promoter sequences of Sncg during 3T3-L1 adipogenesis. Rosiglitazone did not affect Sncg mRNA expression in murine cultured DRG neurons. In subcutaneous human WAT samples from two cohorts treated with pioglitazone (>11 wks), SNCG mRNA expression was reduced, albeit highly variable and most evident in type 2 diabetes. Leptin (Lep) expression, thought to be coordinately-regulated with Sncg based on correlations in human adipose tissue, was also reduced in 3T3-L1 adipocytes by rosiglitazone. However, Lep was unaffected by PPARγ antagonist, and the LXR agonist T0901317 significantly reduced Lep expression (~64%) while not impacting Sncg. The results support the concept that synuclein-γ shares some, but not all, gene regulators with leptin and is a PPARγ target in adipocytes but not DRG neurons. Regulation of synuclein-γ by cues such as PPARγ agonism in adipocytes is logical based on recent evidence for an important role for synuclein-γ in the maintenance and dynamics of adipocyte lipid droplets.
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28
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Monge-Roffarello B, Labbe SM, Roy MC, Lemay ML, Coneggo E, Samson P, Lanfray D, Richard D. The PVH as a site of CB1-mediated stimulation of thermogenesis by MC4R agonism in male rats. Endocrinology 2014; 155:3448-58. [PMID: 24949658 DOI: 10.1210/en.2013-2092] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The present study was designed to investigate the involvement of the cannabinoid receptor 1 (CB1) in the stimulating effects of the melanocortin-4 receptor (MC4R) agonism on whole-body and brown adipose tissue (BAT) thermogenesis. In a first series of experiments, whole-body and BAT thermogenesis were investigated in rats infused in the third ventricle of the brain with the MC4R agonist melanotan II (MTII) and the CB1 agonist δ9-tetrahydrocannabinol (δ(9)-THC) or the CB1 antagonist AM251. Whole-body thermogenesis was measured by indirect calorimetry and BAT thermogenesis assessed from interscapular BAT (iBAT) temperature. δ(9)-THC blunted the effects of MTII on energy expenditure and iBAT temperature, whereas AM251 tended to potentiate the MTII effects. δ(9)-THC also blocked the stimulating effect of MTII on (14)C-bromopalmitate and (3)H-deoxyglucose uptakes in iBAT. Additionally, δ(9)-THC attenuated the stimulating effect of MTII on the expression of peroxisome proliferator-activated receptor-γ coactivator 1-α (Pgc1α), type II iodothyronine deiodinase (Dio2), carnitine palmitoyltransferase 1B (Cpt1b), and uncoupling protein 1 (Ucp1). In a second series of experiments, we addressed the involvement of the paraventricular hypothalamic nucleus (PVH) in the CB1-mediated effects of MTII on iBAT thermogenesis, which were assessed following the infusion of MTII in the PVH and δ(9)-THC or AM251 in the fourth ventricle of the brain. We demonstrated the ability of δ(9)-THC to blunt MTII-induced iBAT temperature elevation. δ(9)-THC also blocked the PVH effect of MTII on (14)C-bromopalmitate uptake as well as on Pgc1α and Dio2 expression in iBAT. Altogether the results of this study demonstrate the involvement of the PVH in the CB1-mediated stimulating effects of the MC4R agonist MTII on whole-body and BAT thermogenesis.
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MESH Headings
- Adipose Tissue, Brown/metabolism
- Animals
- Male
- Paraventricular Hypothalamic Nucleus/metabolism
- Peptides, Cyclic/metabolism
- Piperidines
- Pyrazoles
- Rats
- Rats, Wistar
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Melanocortin, Type 4/agonists
- Receptor, Melanocortin, Type 4/metabolism
- Thermogenesis
- alpha-MSH/analogs & derivatives
- alpha-MSH/metabolism
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Affiliation(s)
- Boris Monge-Roffarello
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada G1V 4G5
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29
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Pfeifer A, Hoffmann LS. Brown, beige, and white: the new color code of fat and its pharmacological implications. Annu Rev Pharmacol Toxicol 2014; 55:207-27. [PMID: 25149919 DOI: 10.1146/annurev-pharmtox-010814-124346] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Brown adipose tissue (BAT) was previously regarded as a special type of fat relevant only for defending hibernating animals and newborns against a cold environment. Recently, BAT has received considerable attention following its (re)discovery in humans. Using glucose tracers, multiple laboratories independently found metabolically active BAT in adults. The enormous metabolic powers of BAT in animal models could make it an attractive target for antiobesity therapies in humans. Here, we review the present knowledge on the role of BAT in energy homeostasis and metabolism, focusing on signaling pathways and potential targets for novel therapeutics. We also shine light on ongoing debates, including those about the true color of brown fat in adults, as well as on the requirements for translation of basic research on BAT into clinical medicine.
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Affiliation(s)
- Alexander Pfeifer
- Institute of Pharmacology and Toxicology, Biomedical Center, University of Bonn, 53105 Bonn, Germany;
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30
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Berglund ED, Liu T, Kong X, Sohn JW, Vong L, Deng Z, Lee CE, Lee S, Williams KW, Olson DP, Scherer PE, Lowell BB, Elmquist JK. Melanocortin 4 receptors in autonomic neurons regulate thermogenesis and glycemia. Nat Neurosci 2014; 17:911-3. [PMID: 24908101 PMCID: PMC4090093 DOI: 10.1038/nn.3737] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 05/06/2014] [Indexed: 01/08/2023]
Abstract
Whether melanocortin 4 receptors (MC4Rs) in extra-hypothalamic neurons, including cholinergic autonomic pre-ganglionic neurons, are required to control energy and glucose homeostasis is unclear. We found that MC4Rs in sympathetic, but not parasympathetic, pre-ganglionic neurons were required to regulate energy expenditure and body weight, including thermogenic responses to diet and cold exposure and 'beiging' of white adipose tissue. Deletion of Mc4r genes in both sympathetic and parasympathetic cholinergic neurons impaired glucose homeostasis.
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Affiliation(s)
- Eric D. Berglund
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | | | - Xingxing Kong
- Division of Endocrinology, Beth Israel Deaconess Medical Center and Harvard Medical School, Harvard University, Boston, MA, 02115, USA
| | - Jong-Woo Sohn
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 305-701, Korea
| | - Linh Vong
- Division of Endocrinology, Beth Israel Deaconess Medical Center and Harvard Medical School, Harvard University, Boston, MA, 02115, USA
| | - Zhuo Deng
- Department of Obstetrics and Gynecology, The First Affiliated Hospital, Medical School of Xi’an Jiaotong University, Xi’an 710061, P.R. China
| | - Charlotte E. Lee
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Syann Lee
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Kevin W. Williams
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, 75390, USA
| | - David P. Olson
- Division of Endocrinology, Department of Pediatrics, University of Michigan, Ann Arbor, Michigan 48105, USA
| | - Philipp E. Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, UT Southwestern Medical Center, Dallas TX, 75390, USA
| | - Bradford B. Lowell
- Division of Endocrinology, Beth Israel Deaconess Medical Center and Harvard Medical School, Harvard University, Boston, MA, 02115, USA
| | - Joel K. Elmquist
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, 75390, USA
- Department of Pharmacology, UT Southwestern Medical Center, Dallas TX, 75390, USA
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31
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Chechi K, Nedergaard J, Richard D. Brown adipose tissue as an anti-obesity tissue in humans. Obes Rev 2014; 15:92-106. [PMID: 24165204 DOI: 10.1111/obr.12116] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 09/06/2013] [Accepted: 09/07/2013] [Indexed: 12/27/2022]
Abstract
During the 11th Stock Conference held in Montreal, Quebec, Canada, world-leading experts came together to present and discuss recent developments made in the field of brown adipose tissue biology. Owing to the vast capacity of brown adipose tissue for burning food energy in the process of thermogenesis, and due to demonstrations of its presence in adult humans, there is tremendous interest in targeting brown adipose tissue as an anti-obesity tissue in humans. However, the future of such therapeutic approaches relies on our understanding of the origin, development, recruitment, activation and regulation of brown adipose tissue in humans. As reviewed here, the 11th Stock Conference was organized around these themes to discuss the recent progress made in each aspect, to identify gaps in our current understanding and to further provide a common groundwork that could support collaborative efforts aimed at a future therapy for obesity, based on brown adipose tissue thermogenesis.
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Affiliation(s)
- K Chechi
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec, Canada
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32
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Censani M, Conroy R, Deng L, Oberfield SE, McMahon DJ, Zitsman JL, Leibel RL, Chung WK, Fennoy I. Weight loss after bariatric surgery in morbidly obese adolescents with MC4R mutations. Obesity (Silver Spring) 2014; 22:225-31. [PMID: 23740648 PMCID: PMC3880391 DOI: 10.1002/oby.20511] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 05/09/2013] [Indexed: 01/13/2023]
Abstract
OBJECTIVE To determine the frequency of Melanocortin 4 Receptor (MC4R) mutations in morbidly obese adolescents undergoing bariatric surgery and compare weight loss outcomes in patients with and without mutations. DESIGN AND METHODS In this prospective cohort study, 135 adolescent patients evaluated for bariatric surgery were screened for MC4R mutations; 56 had 12-month postoperative data available for analysis. RESULTS MC4R mutations were detected in five of the 135 patients (3.7%); four underwent restrictive bariatric surgery. For the three patients with gastric banding, percent excess weight loss (%EWL) postoperatively was 36.0% at 5 years in one, 47% at 4 years in the second, and 85% at 1 year in the third. For the patient with gastric sleeve resection, %EWL of 96% was attained at 1 year postoperatively. The four MC4R cases had a higher, although nonsignificant, %EWL compared to 52 nonmatched controls at 12 months postoperatively (48.6% vs. 23.4%; P < 0.37). When matched by age, sex, and race to 14 controls, there was no significant difference in %EWL (P < 0.31), BMI change (P < 0.27), or absolute weight loss (P < 0.20). CONCLUSION The frequency of MC4R mutations is similar to prior studies, with affected patients showing beneficial weight loss outcomes.
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Affiliation(s)
- Marisa Censani
- Department of Pediatrics, Division of Pediatric Endocrinology, Columbia University Medical Center, New York, NY, United States, 10032
| | - Rushika Conroy
- Department of Pediatrics, Division of Pediatric Endocrinology, Columbia University Medical Center, New York, NY, United States, 10032
| | - Liyong Deng
- Department of Pediatrics, Division of Molecular Genetics, Naomi Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, United States, 10032
| | - Sharon E. Oberfield
- Department of Pediatrics, Division of Pediatric Endocrinology, Columbia University Medical Center, New York, NY, United States, 10032
| | - Donald J. McMahon
- Department of Medicine, Columbia University Medical Center, New York, NY, United States, 10032
| | - Jeffrey L. Zitsman
- Division of Pediatric Surgery, Department of Surgery, Columbia University Medical Center, New York, NY, United States, 10032
| | - Rudy L. Leibel
- Department of Pediatrics, Division of Molecular Genetics, Naomi Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, United States, 10032
- Department of Medicine, Columbia University Medical Center, New York, NY, United States, 10032
| | - Wendy K. Chung
- Department of Pediatrics, Division of Molecular Genetics, Naomi Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, United States, 10032
- Department of Medicine, Columbia University Medical Center, New York, NY, United States, 10032
| | - Ilene Fennoy
- Department of Pediatrics, Division of Pediatric Endocrinology, Columbia University Medical Center, New York, NY, United States, 10032
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33
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Schneider JE, Wise JD, Benton NA, Brozek JM, Keen-Rhinehart E. When do we eat? Ingestive behavior, survival, and reproductive success. Horm Behav 2013; 64:702-28. [PMID: 23911282 DOI: 10.1016/j.yhbeh.2013.07.005] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 07/21/2013] [Accepted: 07/22/2013] [Indexed: 12/13/2022]
Abstract
The neuroendocrinology of ingestive behavior is a topic central to human health, particularly in light of the prevalence of obesity, eating disorders, and diabetes. The study of food intake in laboratory rats and mice has yielded some useful hypotheses, but there are still many gaps in our knowledge. Ingestive behavior is more complex than the consummatory act of eating, and decisions about when and how much to eat usually take place in the context of potential mating partners, competitors, predators, and environmental fluctuations that are not present in the laboratory. We emphasize appetitive behaviors, actions that bring animals in contact with a goal object, precede consummatory behaviors, and provide a window into motivation. Appetitive ingestive behaviors are under the control of neural circuits and neuropeptide systems that control appetitive sex behaviors and differ from those that control consummatory ingestive behaviors. Decreases in the availability of oxidizable metabolic fuels enhance the stimulatory effects of peripheral hormones on appetitive ingestive behavior and the inhibitory effects on appetitive sex behavior, putting a new twist on the notion of leptin, insulin, and ghrelin "resistance." The ratio of hormone concentrations to the availability of oxidizable metabolic fuels may generate a critical signal that schedules conflicting behaviors, e.g., mate searching vs. foraging, food hoarding vs. courtship, and fat accumulation vs. parental care. In species representing every vertebrate taxa and even in some invertebrates, many putative "satiety" or "hunger" hormones function to schedule ingestive behavior in order to optimize reproductive success in environments where energy availability fluctuates.
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Affiliation(s)
- Jill E Schneider
- Department of Biological Sciences, Lehigh University, 111 Research Drive, Bethlehem, PA 18015, USA
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34
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Girardet C, Butler AA. Neural melanocortin receptors in obesity and related metabolic disorders. Biochim Biophys Acta Mol Basis Dis 2013; 1842:482-94. [PMID: 23680515 DOI: 10.1016/j.bbadis.2013.05.004] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 04/16/2013] [Accepted: 05/03/2013] [Indexed: 12/11/2022]
Abstract
Obesity is a global health issue, as it is associated with increased risk of developing chronic conditions associated with disorders of metabolism such as type 2 diabetes and cardiovascular disease. A better understanding of how excessive fat accumulation develops and causes diseases of the metabolic syndrome is urgently needed. The hypothalamic melanocortin system is an important point of convergence connecting signals of metabolic status with the neural circuitry that governs appetite and the autonomic and neuroendocrine system controling metabolism. This system has a critical role in the defense of body weight and maintenance of homeostasis. Two neural melanocortin receptors, melanocortin 3 and 4 receptors (MC3R and MC4R), play crucial roles in the regulation of energy balance. Mutations in the MC4R gene are the most common cause of monogenic obesity in humans, and a large literature indicates a role in regulating both energy intake through the control of satiety and energy expenditure. In contrast, MC3Rs have a more subtle role in energy homeostasis. Results from our lab indicate an important role for MC3Rs in synchronizing rhythms in foraging behavior with caloric cues and maintaining metabolic homeostasis during periods of nutrient scarcity. However, while deletion of the Mc3r gene in mice alters nutrient partitioning to favor accumulation of fat mass no obvious role for MC3R haploinsufficiency in human obesity has been reported. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.
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MESH Headings
- Animals
- Body Weight/genetics
- Cardiovascular Diseases/complications
- Cardiovascular Diseases/metabolism
- Cardiovascular Diseases/pathology
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Humans
- Metabolic Diseases/genetics
- Metabolic Diseases/metabolism
- Metabolic Diseases/pathology
- Mice
- Obesity/complications
- Obesity/genetics
- Obesity/metabolism
- Obesity/pathology
- Receptor, Melanocortin, Type 3/genetics
- Receptor, Melanocortin, Type 3/metabolism
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
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Affiliation(s)
- Clemence Girardet
- Department of Metabolism and Aging, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Andrew A Butler
- Department of Metabolism and Aging, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA.
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35
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Abstract
The central melanocortin system plays an essential role in the regulation of energy metabolism. Key to this regulation are the responses of neurons expressing proopiomelanocortin (POMC) and agouti-related protein (AgRP) to blood-borne metabolic signals. Recent evidence has demonstrated that POMC and AgRP neurons are not simply mirror opposites of each other in function and responsiveness to metabolic signals, nor are they exclusively first-order neurons. These neurons act as central transceivers, integrating both hormonal and neural signals, and then transmitting this information to peripheral tissues via the autonomic nervous system to coordinate whole-body energy metabolism. This review focuses on most recent developments obtained from rodent studies on the function, metabolic regulation, and circuitry of the central melanocortin system.
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Affiliation(s)
- James P. Warne
- Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Allison W. Xu
- Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA
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36
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Vaughan CH, Bartness TJ. Anterograde transneuronal viral tract tracing reveals central sensory circuits from brown fat and sensory denervation alters its thermogenic responses. Am J Physiol Regul Integr Comp Physiol 2012; 302:R1049-58. [PMID: 22378771 DOI: 10.1152/ajpregu.00640.2011] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Brown adipose tissue (BAT) thermogenic activity and growth are controlled by its sympathetic nervous system (SNS) innervation, but nerve fibers containing sensory-associated neuropeptides [substance P, calcitonin gene-related peptide (CGRP)] also suggest sensory innervation. The central nervous system (CNS) projections of BAT afferents are unknown. Therefore, we used the H129 strain of the herpes simplex virus-1 (HSV-1), an anterograde transneuronal viral tract tracer used to delineate sensory nerve circuits, to define these projections. HSV-1 was injected into interscapular BAT (IBAT) of Siberian hamsters and HSV-1 immunoreactivity (ir) was assessed 24, 48, 72, 96, and 114 h postinjection. The 96- and 114-h groups had the most HSV-1-ir neurons with marked infections in the hypothalamic paraventricular nucleus, periaqueductal gray, olivary areas, parabrachial nuclei, raphe nuclei, and reticular areas. These sites also are involved in sympathetic outflow to BAT suggesting possible BAT sensory-SNS thermogenesis feedback circuits. We tested the functional contribution of IBAT sensory innervation on thermogenic responses to an acute (24 h) cold exposure test by injecting the specific sensory nerve toxin capsaicin directly into IBAT pads and then measuring core (T(c)) and IBAT (T(IBAT)) temperature responses. CGRP content was significantly decreased in capsaicin-treated IBAT demonstrating successful sensory nerve destruction. T(IBAT) and T(c) were significantly decreased in capsaicin-treated hamsters compared with the saline controls at 2 h of cold exposure. Thus the central sensory circuits from IBAT have been delineated for the first time, and impairment of sensory feedback from BAT appears necessary for the appropriate, initial thermogenic response to acute cold exposure.
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Affiliation(s)
- Cheryl H Vaughan
- Dept. of Biology, Georgia State Univ., Atlanta, GA 30302-4010, USA
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