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Reichenbach A, Dempsey H, Andrews ZB. Metabolic sensing in AgRP regulates sucrose preference and dopamine release in the nucleus accumbens. J Neuroendocrinol 2024; 36:e13389. [PMID: 38599683 DOI: 10.1111/jne.13389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/18/2024] [Accepted: 03/26/2024] [Indexed: 04/12/2024]
Abstract
Hunger increases the motivation for calorie consumption, often at the expense of low-taste appeal. However, the neural mechanisms integrating calorie-sensing with increased motivation for calorie consumption remain unknown. Agouti-related peptide (AgRP) neurons in the arcuate nucleus of the hypothalamus sense hunger, and the ingestion of caloric solutions promotes dopamine release in the absence of sweet taste perception. Therefore, we hypothesised that metabolic-sensing of hunger by AgRP neurons would be essential to promote dopamine release in the nucleus accumbens in response to caloric, but not non-caloric solutions. Moreover, we examined whether metabolic sensing in AgRP neurons affected taste preference for bitter solutions under conditions of energy need. Here we show that impaired metabolic sensing in AgRP neurons attenuated nucleus accumbens dopamine release in response to sucrose, but not saccharin, consumption. Furthermore, metabolic sensing in AgRP neurons was essential to distinguish nucleus accumbens dopamine response to sucrose consumption when compared with saccharin. Under conditions of hunger, metabolic sensing in AgRP neurons increased the preference for sucrose solutions laced with the bitter tastant, quinine, to ensure calorie consumption, whereas mice with impaired metabolic sensing in AgRP neurons maintained a strong aversion to sucrose/quinine solutions despite ongoing hunger. In conclusion, we demonstrate normal metabolic sensing in AgRP neurons drives the preference for calorie consumption, primarily when needed, by engaging dopamine release in the nucleus accumbens.
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Affiliation(s)
- Alex Reichenbach
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Harry Dempsey
- Florey Institute of Neuroscience & Mental Health, Parkville, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
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Sayar-Atasoy N, Aklan I, Yavuz Y, Laule C, Kim H, Rysted J, Alp MI, Davis D, Yilmaz B, Atasoy D. AgRP neurons encode circadian feeding time. Nat Neurosci 2024; 27:102-115. [PMID: 37957320 DOI: 10.1038/s41593-023-01482-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 10/05/2023] [Indexed: 11/15/2023]
Abstract
Food intake follows a predictable daily pattern and synchronizes metabolic rhythms. Neurons expressing agouti-related protein (AgRP) read out physiological energetic state and elicit feeding, but the regulation of these neurons across daily timescales is poorly understood. Using a combination of neuron dynamics measurements and timed optogenetic activation in mice, we show that daily AgRP-neuron activity was not fully consistent with existing models of homeostatic regulation. Instead of operating as a 'deprivation counter', AgRP-neuron activity primarily followed the circadian rest-activity cycle through a process that required an intact suprachiasmatic nucleus and synchronization by light. Imposing novel feeding patterns through time-restricted food access or periodic AgRP-neuron stimulation was sufficient to resynchronize the daily AgRP-neuron activity rhythm and drive anticipatory-like behavior through a process that required DMHPDYN neurons. These results indicate that AgRP neurons integrate time-of-day information of past feeding experience with current metabolic needs to predict circadian feeding time.
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Affiliation(s)
- Nilufer Sayar-Atasoy
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Iltan Aklan
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Yavuz Yavuz
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
- Department of Physiology, School of Medicine, Yeditepe University, Istanbul, Turkey
| | - Connor Laule
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Hyojin Kim
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Jacob Rysted
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Muhammed Ikbal Alp
- Department of Physiology, School of Medicine, Regenerative and Restorative Medical Research Center (REMER), Istanbul Medipol University, Istanbul, Turkey
| | - Debbie Davis
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
| | - Bayram Yilmaz
- Department of Physiology, School of Medicine, Yeditepe University, Istanbul, Turkey
| | - Deniz Atasoy
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA.
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA.
- Fraternal Order of Eagles Diabetes Research Center (FOEDRC), Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
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Zagmutt S, Mera P, González-García I, Ibeas K, Romero MDM, Obri A, Martin B, Esteve-Codina A, Soler-Vázquez MC, Bastias-Pérez M, Cañes L, Augé E, Pelegri C, Vilaplana J, Ariza X, García J, Martinez-González J, Casals N, López M, Palmiter R, Sanz E, Quintana A, Herrero L, Serra D. CPT1A in AgRP neurons is required for sex-dependent regulation of feeding and thirst. Biol Sex Differ 2023; 14:14. [PMID: 36966335 PMCID: PMC10040140 DOI: 10.1186/s13293-023-00498-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 03/10/2023] [Indexed: 03/27/2023] Open
Abstract
BACKGROUND Fatty acid metabolism in the hypothalamus has an important role in food intake, but its specific role in AgRP neurons is poorly understood. Here, we examined whether carnitinea palmitoyltransferase 1A (CPT1A), a key enzyme in mitochondrial fatty acid oxidation, affects energy balance. METHODS To obtain Cpt1aKO mice and their control littermates, Cpt1a(flox/flox) mice were crossed with tamoxifen-inducible AgRPCreERT2 mice. Food intake and body weight were analyzed weekly in both males and females. At 12 weeks of age, metabolic flexibility was determined by ghrelin-induced food intake and fasting-refeeding satiety tests. Energy expenditure was analyzed by calorimetric system and thermogenic activity of brown adipose tissue. To study fluid balance the analysis of urine and water intake volumes; osmolality of urine and plasma; as well as serum levels of angiotensin and components of RAAS (renin-angiotensin-aldosterone system) were measured. At the central level, changes in AgRP neurons were determined by: (1) analyzing specific AgRP gene expression in RiboTag-Cpt1aKO mice obtained by crossing Cpt1aKO mice with RiboTag mice; (2) measuring presynaptic terminal formation in the AgRP neurons with the injection of the AAV1-EF1a-DIO-synaptophysin-GFP in the arcuate nucleus of the hypothalamus; (3) analyzing AgRP neuronal viability and spine formations by the injection AAV9-EF1a-DIO-mCherry in the arcuate nucleus of the hypothalamus; (4) analyzing in situ the specific AgRP mitochondria in the ZsGreen-Cpt1aKO obtained by breeding ZsGreen mice with Cpt1aKO mice. Two-way ANOVA analyses were performed to determine the contributions of the effect of lack of CPT1A in AgRP neurons in the sex. RESULTS Changes in food intake were just seen in male Cpt1aKO mice while only female Cpt1aKO mice increased energy expenditure. The lack of Cpt1a in the AgRP neurons enhanced brown adipose tissue activity, mainly in females, and induced a substantial reduction in fat deposits and body weight. Strikingly, both male and female Cpt1aKO mice showed polydipsia and polyuria, with more reduced serum vasopressin levels in females and without osmolality alterations, indicating a direct involvement of Cpt1a in AgRP neurons in fluid balance. AgRP neurons from Cpt1aKO mice showed a sex-dependent gene expression pattern, reduced mitochondria and decreased presynaptic innervation to the paraventricular nucleus, without neuronal viability alterations. CONCLUSIONS Our results highlight that fatty acid metabolism and CPT1A in AgRP neurons show marked sex differences and play a relevant role in the neuronal processes necessary for the maintenance of whole-body fluid and energy balance.
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Affiliation(s)
- Sebastián Zagmutt
- Department of Biochemistry and Physiology, School of Pharmacy and Food Sciences, Universitat de Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Paula Mera
- Department of Biochemistry and Physiology, School of Pharmacy and Food Sciences, Universitat de Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Ismael González-García
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain
| | - Kevin Ibeas
- Department of Biochemistry and Physiology, School of Pharmacy and Food Sciences, Universitat de Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - María Del Mar Romero
- Department of Biochemistry and Physiology, School of Pharmacy and Food Sciences, Universitat de Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Arnaud Obri
- Neuronal Control of Metabolism Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Beatriz Martin
- CNAG-CRG, Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08028, Barcelona, Spain
| | - Anna Esteve-Codina
- CNAG-CRG, Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08028, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - M Carmen Soler-Vázquez
- Department of Biochemistry and Physiology, School of Pharmacy and Food Sciences, Universitat de Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Marianela Bastias-Pérez
- Department of Biochemistry and Physiology, School of Pharmacy and Food Sciences, Universitat de Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Laia Cañes
- Instituto de Investigaciones Biomédicas de Barcelona (IIBB-CSIC), Barcelona, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Instituto de Salud Carlos III, Madrid, Spain
- Instituto de Investigación Biomédica Sant Pau (IIB-Sant Pau), Barcelona, Spain
| | - Elisabeth Augé
- Department of Biochemistry and Physiology, School of Pharmacy and Food Sciences, Universitat de Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Carme Pelegri
- Department of Biochemistry and Physiology, School of Pharmacy and Food Sciences, Universitat de Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Institute of Neurosciences of the Universitat de Barcelona, Barcelona, Spain
| | - Jordi Vilaplana
- Department of Biochemistry and Physiology, School of Pharmacy and Food Sciences, Universitat de Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
- Biomedical Research Networking Centre in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Institute of Neurosciences of the Universitat de Barcelona, Barcelona, Spain
| | - Xavier Ariza
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
- Department of Inorganic & Organic Chemistry, Faculty of Chemistry, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Jordi García
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
- Department of Inorganic & Organic Chemistry, Faculty of Chemistry, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - José Martinez-González
- Instituto de Investigaciones Biomédicas de Barcelona (IIBB-CSIC), Barcelona, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), Instituto de Salud Carlos III, Madrid, Spain
- Instituto de Investigación Biomédica Sant Pau (IIB-Sant Pau), Barcelona, Spain
| | - Núria Casals
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
- Department of Basic Sciences, Faculty of Medicine & Health Sciences, Universitat Internacional de Catalunya, Sant Cugat del Vallès, Spain
| | - Miguel López
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain
| | - Richard Palmiter
- Department of Biochemistry, Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Elisenda Sanz
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Albert Quintana
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Laura Herrero
- Department of Biochemistry and Physiology, School of Pharmacy and Food Sciences, Universitat de Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Dolors Serra
- Department of Biochemistry and Physiology, School of Pharmacy and Food Sciences, Universitat de Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain.
- Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, Barcelona, Spain.
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain.
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Tang D, Tang Q, Huang W, Zhang Y, Tian Y, Fu X. Fasting: From Physiology to Pathology. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2204487. [PMID: 36737846 PMCID: PMC10037992 DOI: 10.1002/advs.202204487] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 01/06/2023] [Indexed: 06/18/2023]
Abstract
Overnutrition is a risk factor for various human diseases, including neurodegenerative diseases, metabolic disorders, and cancers. Therefore, targeting overnutrition represents a simple but attractive strategy for the treatment of these increasing public health threats. Fasting as a dietary intervention for combating overnutrition has been extensively studied. Fasting has been practiced for millennia, but only recently have its roles in the molecular clock, gut microbiome, and tissue homeostasis and function emerged. Fasting can slow aging in most species and protect against various human diseases, including neurodegenerative diseases, metabolic disorders, and cancers. These centuried and unfading adventures and explorations suggest that fasting has the potential to delay aging and help prevent and treat diseases while minimizing side effects caused by chronic dietary interventions. In this review, recent animal and human studies concerning the role and underlying mechanism of fasting in physiology and pathology are summarized, the therapeutic potential of fasting is highlighted, and the combination of pharmacological intervention and fasting is discussed as a new treatment regimen for human diseases.
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Affiliation(s)
- Dongmei Tang
- Division of Endocrinology and Metabolism, National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuan610041China
| | - Qiuyan Tang
- Neurology Department of Integrated Traditional Chinese and Western Medicine, School of Clinical MedicineChengdu University of Traditional Chinese MedicineChengduSichuan610075China
| | - Wei Huang
- West China Centre of Excellence for PancreatitisInstitute of Integrated Traditional Chinese and Western MedicineWest China‐Liverpool Biomedical Research CentreWest China HospitalSichuan UniversityChengduSichuan610041China
| | - Yuwei Zhang
- Division of Endocrinology and MetabolismWest China HospitalSichuan UniversityChengduSichuan610041China
| | - Yan Tian
- Division of Endocrinology and Metabolism, National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy and Cancer Center, West China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuan610041China
| | - Xianghui Fu
- Division of Endocrinology and Metabolism, National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy and Cancer Center, West China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuan610041China
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5
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Rawlinson S, Reichenbach A, Clarke RE, Nuñez-Iglesias J, Dempsey H, Lockie SH, Andrews ZB. In Vivo Photometry Reveals Insulin and 2-Deoxyglucose Maintain Prolonged Inhibition of VMH Vglut2 Neurons in Male Mice. Endocrinology 2022; 163:6631280. [PMID: 35788848 DOI: 10.1210/endocr/bqac095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Indexed: 11/19/2022]
Abstract
The ventromedial hypothalamic (VMH) nucleus is a well-established hub for energy and glucose homeostasis. In particular, VMH neurons are thought to be important for initiating the counterregulatory response to hypoglycemia, and ex vivo electrophysiology and immunohistochemistry data indicate a clear role for VMH neurons in sensing glucose concentration. However, the temporal response of VMH neurons to physiologically relevant changes in glucose availability in vivo has been hampered by a lack of available tools for measuring neuronal activity over time. Since the majority of neurons within the VMH are glutamatergic and can be targeted using the vesicular glutamate transporter Vglut2, we expressed cre-dependent GCaMP7s in Vglut2 cre mice and examined the response profile of VMH to intraperitoneal injections of glucose, insulin, and 2-deoxyglucose (2DG). We show that reduced available glucose via insulin-induced hypoglycemia and 2DG-induced glucoprivation, but not hyperglycemia induced by glucose injection, inhibits VMH Vglut2 neuronal population activity in vivo. Surprisingly, this inhibition was maintained for at least 45 minutes despite prolonged hypoglycemia and initiation of a counterregulatory response. Thus, although VMH stimulation, via pharmacological, electrical, or optogenetic approaches, is sufficient to drive a counterregulatory response, our data suggest VMH Vglut2 neurons are not the main drivers required to do so, since VMH Vglut2 neuronal population activity remains suppressed during hypoglycemia and glucoprivation.
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Affiliation(s)
- Sasha Rawlinson
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, 3800, Australia
| | - Alex Reichenbach
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, 3800, Australia
| | - Rachel E Clarke
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | - Juan Nuñez-Iglesias
- Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, 3800, Australia
| | - Harry Dempsey
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, 3800, Australia
| | - Sarah H Lockie
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, 3800, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, 3800, Australia
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Reichenbach A, Clarke RE, Stark R, Lockie SH, Mequinion M, Dempsey H, Rawlinson S, Reed F, Sepehrizadeh T, DeVeer M, Munder AC, Nunez-Iglesias J, Spanswick D, Mynatt R, Kravitz AV, Dayas CV, Brown R, Andrews ZB. Metabolic sensing in AgRP neurons integrates homeostatic state with dopamine signalling in the striatum. eLife 2022; 11:72668. [PMID: 35018884 PMCID: PMC8803314 DOI: 10.7554/elife.72668] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 01/11/2022] [Indexed: 11/17/2022] Open
Abstract
Agouti-related peptide (AgRP) neurons increase motivation for food, however, whether metabolic sensing of homeostatic state in AgRP neurons potentiates motivation by interacting with dopamine reward systems is unexplored. As a model of impaired metabolic-sensing, we used the AgRP-specific deletion of carnitine acetyltransferase (Crat) in mice. We hypothesised that metabolic sensing in AgRP neurons is required to increase motivation for food reward by modulating accumbal or striatal dopamine release. Studies confirmed that Crat deletion in AgRP neurons (KO) impaired ex vivo glucose-sensing, as well as in vivo responses to peripheral glucose injection or repeated palatable food presentation and consumption. Impaired metabolic-sensing in AgRP neurons reduced acute dopamine release (seconds) to palatable food consumption and during operant responding, as assessed by GRAB-DA photometry in the nucleus accumbens, but not the dorsal striatum. Impaired metabolic-sensing in AgRP neurons suppressed radiolabelled 18F-fDOPA accumulation after ~30 min in the dorsal striatum but not the nucleus accumbens. Impaired metabolic sensing in AgRP neurons suppressed motivated operant responding for sucrose rewards during fasting. Thus, metabolic-sensing in AgRP neurons is required for the appropriate temporal integration and transmission of homeostatic hunger-sensing to dopamine signalling in the striatum.
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Affiliation(s)
| | - Rachel E Clarke
- Department of Physiology, Monash University, Clayton, Australia
| | - Romana Stark
- Department of Physiology, Monash University, Clayton, Australia
| | - Sarah H Lockie
- Department of Physiology, Monash University, Clayton, Australia
| | | | - Harry Dempsey
- Department of Physiology, Monash University, Clayton, Australia
| | - Sasha Rawlinson
- Department of Physiology, Monash University, Clayton, Australia
| | - Felicia Reed
- Department of Physiology, Monash University, Clayton, Australia
| | - Tara Sepehrizadeh
- Monash Biomedical Imaging Facility, Monash University, Clayton, Australia
| | - Michael DeVeer
- Monash Biomedical Imaging Facility, Monash University, Clayton, Australia
| | - Astrid C Munder
- Department of Physiology, Monash University, Clayton, Australia
| | - Juan Nunez-Iglesias
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Australia
| | - David Spanswick
- Department of Physiology, Monash University, Clayton, Australia
| | - Randall Mynatt
- Gene Nutrient Interactions Laboratory, Pennington Biomedical Research Center, Baton Rouge, United States
| | - Alexxai V Kravitz
- Departments of Psychiatry, Washington University in St. Louis, Saint Louis, United States
| | - Christopher V Dayas
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, Australia
| | - Robyn Brown
- Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, Australia
| | - Zane B Andrews
- Department of Physiology, Monash University, Clayton, Australia
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7
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Cavalcanti-de-Albuquerque JP, Donato J. Rolling out physical exercise and energy homeostasis: Focus on hypothalamic circuitries. Front Neuroendocrinol 2021; 63:100944. [PMID: 34425188 DOI: 10.1016/j.yfrne.2021.100944] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 08/11/2021] [Accepted: 08/18/2021] [Indexed: 01/17/2023]
Abstract
Energy balance is the fine regulation of energy expenditure and energy intake. Negative energy balance causes body weight loss, while positive energy balance promotes weight gain. Modern societies offer a maladapted way of life, where easy access to palatable foods and the lack of opportunities to perform physical activity are considered the roots of the obesity pandemic. Physical exercise increases energy expenditure and, consequently, is supposed to promote weight loss. Paradoxically, physical exercise acutely drives anorexigenic-like effects, but the mechanisms are still poorly understood. Using an evolutionary background, this review aims to highlight the potential involvement of the melanocortin system and other hypothalamic neural circuitries regulating energy balance during and after physical exercise. The physiological significance of these changes will be explored, and possible signalling agents will be addressed. The knowledge discussed here might be important for clarifying obesity aetiology as well as new therapeutic approaches for body weight loss.
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Affiliation(s)
| | - José Donato
- Department of Physiology and Biophysics, University of São Paulo, São Paulo 05508-900, Brazil.
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8
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Andrews ZB. Neurobiology: How to ask a mouse if it's hungry. Curr Biol 2021; 31:R1056-R1058. [PMID: 34520719 DOI: 10.1016/j.cub.2021.07.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Neural circuits influence food intake by responding to interoceptive hunger cues and/or hedonic cues. A new study utilizes a hunger discrimination behavioural task combined with opto- and chemo-genetic manipulation to identify hunger and non-hunger sensing neural circuits driving food intake.
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Affiliation(s)
- Zane B Andrews
- Department of Physiology, Monash University, Clayton, VIC 3800, Australia.
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9
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Hypothalamic control of interoceptive hunger. Curr Biol 2021; 31:3797-3809.e5. [PMID: 34273280 DOI: 10.1016/j.cub.2021.06.048] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 05/06/2021] [Accepted: 06/16/2021] [Indexed: 01/08/2023]
Abstract
While energy balance is critical to survival, many factors influence food intake beyond caloric need or "hunger." Despite this, some neurons that drive feeding in mice are routinely referred to as "hunger neurons," whereas others are not. To understand how specific hypothalamic circuits control interoceptive hunger, we trained mice to discriminate fasted from sated periods. We then manipulated three hypothalamic neuronal populations with well-known effects on feeding while mice performed this task. While activation of ARCAGRP neurons in sated mice caused mice to report being food-restricted, LHVGAT neuron activation or LHVGLUT2 neuron inhibition did not. In contrast, LHVGAT neuron inhibition or LHVGLUT2 neuron activation in fasted mice attenuated natural hunger, whereas ARCAGRP neuron inhibition did not. Each neuronal population evoked distinct effects on food consumption and reward. After satiety- or sickness-induced devaluation, ARCAGRP neurons drove calorie-specific feeding, while LHVGAT neurons drove calorie-indiscriminate food intake. Our data support a role for ARCAGRP neurons in homeostatic feeding and implicate them in driving a hunger-like internal state that directs behavior toward caloric food sources. Moreover, manipulations of LH circuits did not evoke hunger-like effects in sated mice, suggesting that they may govern feeding more related to reward, compulsion, or generalized consumption than to energy balance, but also that these LH circuits can be powerful negative appetite modulators in fasted mice. This study highlights the complexity of hypothalamic feeding regulation and can be used as a framework to characterize how other neuronal circuits affect hunger and identify potential therapeutic targets for eating disorders.
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10
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Chronic glucocorticoid treatment induces hepatic lipid accumulation and hyperinsulinaemia in part through actions on AgRP neurons. Sci Rep 2021; 11:13776. [PMID: 34215821 PMCID: PMC8253818 DOI: 10.1038/s41598-021-93378-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 06/04/2021] [Indexed: 11/08/2022] Open
Abstract
Glucocorticoids (GCs) are widely prescribed anti-inflammatory medicines, but their use can lead to metabolic side-effects. These may occur through direct actions of GCs on peripheral organs, but could also be mediated by the hypothalamic AgRP neurons, which can increase food intake and modify peripheral metabolism. Therefore, the aim of this study was to examine the metabolic effects of chronic treatment with the GC corticosterone (Cort, 75 μg/ml in drinking water) in mice lacking the glucocorticoid receptor (GR) on AgRP neurons. Female AgRP-GR KO mice had delayed onset of Cort-induced hyperphagia. However, AgRP-GR KO had little impact on the increased body weight or adiposity seen with 3 weeks Cort treatment. Cort caused hepatic steatosis in control mice, but in Cort treated female AgRP-GR KO mice there was a 25% reduction in liver lipid content and lower plasma triglycerides. Additionally, Cort treatment led to hyperinsulinaemia, but compared to controls, Cort-treated AgRP-GR KO mice had both lower fasting insulin levels and lower insulin levels during a glucose tolerance test. In conclusion, these data indicate that GCs do act through AgRP neurons to contribute, at least in part, to the adverse metabolic consequences of chronic GC treatment.
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11
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Enriquez RF, Lee NJ, Herzog H. AgRP signalling negatively regulates bone mass. J Neuroendocrinol 2021; 33:e12978. [PMID: 33913541 DOI: 10.1111/jne.12978] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 11/28/2022]
Abstract
The central nervous system is an active and major regulator of bone structure and remodelling. Specifically, signalling within the hypothalamus has been shown to be critical to ensuring that skeletal functions align with whole body metabolic supply and demand. Here, we identify agouti-related peptide (AgRP), an orexigenic peptide exclusively co-expressed with neuropeptide Y (NPY) in the arcuate nucleus (ARC) of the hypothalamus, as another critical player in the central control of bone homeostasis. Using novel mouse models, we show that AgRP deletion leads to an increase in cortical and trabecular bone mass as a result of an increase in bone thickness despite a lean phenotype, particularly in male mice. Interestingly, male AgRP deficient mice display a significant decrease in pro-opiomelanocortin (POMC) expression in the ARC, but no change in NPY or CART expression, suggesting that the increase in bone mass in AgRP-deficient mice is unlikely to be a result of altered NPY signalling. This is consistent with the observation that bone mass is unchanged in response to the specific deletion of NPY from AgRP expressing neurones. By contrast, POMC expression in the ARC is significantly increased in female AgRP deficient mice, although AgRP deletion results in altered respiratory exchange ratio regulation in response to re-feeding after a fast in both sexes. Taken together, the present study identifies AgRP as being directly involved in the regulation of bone mass and highlights the complexity intrinsic to the neuropeptide regulation of the skeleton.
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Affiliation(s)
- Ronaldo F Enriquez
- Eating Disorders Group, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Nicola J Lee
- Eating Disorders Group, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
- St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia
| | - Herbert Herzog
- Eating Disorders Group, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
- St Vincent's Clinical School, UNSW Sydney, Sydney, NSW, Australia
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12
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Franczyk MP, Qi N, Stromsdorfer KL, Li C, Yamaguchi S, Itoh H, Yoshino M, Sasaki Y, Brookheart RT, Finck BN, DeBosch BJ, Klein S, Yoshino J. Importance of Adipose Tissue NAD+ Biology in Regulating Metabolic Flexibility. Endocrinology 2021; 162:6128705. [PMID: 33543238 PMCID: PMC7853299 DOI: 10.1210/endocr/bqab006] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Indexed: 12/17/2022]
Abstract
Nicotinamide adenine dinucleotide (NAD+) is an essential coenzyme that regulates cellular energy metabolism in many cell types. The major purpose of the present study was to test the hypothesis that NAD+ in white adipose tissue (WAT) is a regulator of whole-body metabolic flexibility in response to changes in insulin sensitivity and with respect to substrate availability and use during feeding and fasting conditions. To this end, we first evaluated the relationship between WAT NAD+ concentration and metabolic flexibility in mice and humans. We found that WAT NAD+ concentration was increased in mice after calorie restriction and exercise, 2 enhancers of metabolic flexibility. Bariatric surgery-induced 20% weight loss increased plasma adiponectin concentration, skeletal muscle insulin sensitivity, and WAT NAD+ concentration in people with obesity. We next analyzed adipocyte-specific nicotinamide phosphoribosyltransferase (Nampt) knockout (ANKO) mice, which have markedly decreased NAD+ concentrations in WAT. ANKO mice oxidized more glucose during the light period and after fasting than control mice. In contrast, the normal postprandial stimulation of glucose oxidation and suppression of fat oxidation were impaired in ANKO mice. Data obtained from RNA-sequencing of WAT suggest that loss of NAMPT increases inflammation, and impairs insulin sensitivity, glucose oxidation, lipolysis, branched-chain amino acid catabolism, and mitochondrial function in WAT, which are features of metabolic inflexibility. These results demonstrate a novel function of WAT NAMPT-mediated NAD+ biosynthesis in regulating whole-body metabolic flexibility, and provide new insights into the role of adipose tissue NAD+ biology in metabolic health.
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Affiliation(s)
- Michael P Franczyk
- Center for Human Nutrition, Washington University School of Medicine, St Louis, Missouri, USA
| | - Nathan Qi
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Kelly L Stromsdorfer
- Center for Human Nutrition, Washington University School of Medicine, St Louis, Missouri, USA
| | - Chengcheng Li
- Center for Human Nutrition, Washington University School of Medicine, St Louis, Missouri, USA
| | - Shintaro Yamaguchi
- Center for Human Nutrition, Washington University School of Medicine, St Louis, Missouri, USA
- Division of Endocrinology, Metabolism and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Hiroshi Itoh
- Division of Endocrinology, Metabolism and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Mihoko Yoshino
- Center for Human Nutrition, Washington University School of Medicine, St Louis, Missouri, USA
| | - Yo Sasaki
- Department of Genetics, Washington University School of Medicine, St Louis, Missouri, USA
| | - Rita T Brookheart
- Center for Human Nutrition, Washington University School of Medicine, St Louis, Missouri, USA
| | - Brian N Finck
- Center for Human Nutrition, Washington University School of Medicine, St Louis, Missouri, USA
| | - Brian J DeBosch
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, USA
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Samuel Klein
- Center for Human Nutrition, Washington University School of Medicine, St Louis, Missouri, USA
| | - Jun Yoshino
- Center for Human Nutrition, Washington University School of Medicine, St Louis, Missouri, USA
- Department of Developmental Biology, Washington University School of Medicine, St Louis, Missouri, USA
- Correspondence: Jun Yoshino, MD, PhD, Center for Human Nutrition, Division of Geriatrics & Nutritional Science, Washington University School of Medicine, 660 S Euclid Ave, Campus Box 8031, St Louis, MO 63110, USA.
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13
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Berdous D, Berney X, Sanchez-Archidona AR, Jan M, Roujeau C, Lopez-Mejia IC, Mynatt R, Thorens B. A genetic screen identifies Crat as a regulator of pancreatic beta-cell insulin secretion. Mol Metab 2020; 37:100993. [PMID: 32298772 PMCID: PMC7225740 DOI: 10.1016/j.molmet.2020.100993] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 04/02/2020] [Accepted: 04/02/2020] [Indexed: 11/28/2022] Open
Abstract
Objectives Glucose-stimulated insulin secretion is a critical function in the regulation of glucose homeostasis, and its deregulation is associated with the development of type 2 diabetes. Here, we performed a genetic screen using islets isolated from the BXD panel of advanced recombinant inbred (RI) lines of mice to search for novel regulators of insulin production and secretion. Methods Pancreatic islets were isolated from 36 RI BXD lines and insulin secretion was measured following exposure to 2.8 or 16.7 mM glucose with or without exendin-4. Islets from the same RI lines were used for RNA extraction and transcript profiling. Quantitative trait loci (QTL) mapping was performed for each secretion condition and combined with transcriptome data to prioritize candidate regulatory genes within the identified QTL regions. Functional studies were performed by mRNA silencing or overexpression in MIN6B1 cells and by studying mice and islets with beta-cell-specific gene inactivation. Results Insulin secretion under the 16.7 mM glucose plus exendin-4 condition was mapped significantly to a chromosome 2 QTL. Within this QTL, RNA-Seq data prioritized Crat (carnitine O-acetyl transferase) as a strong candidate regulator of the insulin secretion trait. Silencing Crat expression in MIN6B1 cells reduced insulin content and insulin secretion by ∼30%. Conversely, Crat overexpression enhanced insulin content and secretion by ∼30%. When islets from mice with beta-cell-specific Crat inactivation were exposed to high glucose, they displayed a 30% reduction of insulin content as compared to control islets. We further showed that decreased Crat expression in both MIN6B1 cells and pancreatic islets reduced the oxygen consumption rate in a glucose concentration-dependent manner. Conclusions We identified Crat as a regulator of insulin secretion whose action is mediated by an effect on total cellular insulin content; this effect also depends on the genetic background of the RI mouse lines. These data also show that in the presence of the stimulatory conditions used the insulin secretion rate is directly related to the insulin content. A QTL analysis in BXD mice identifies Crat as a regulator of insulin secretion. Crat regulates insulin content in MIN6B1 cells and pancreatic islets. Crat regulates glucose oxidation in MIN6B1 cells and pancreatic islets. Crat links glucose metabolism to the control of beta-cell insulin content. Insulin content limits insulin secretion in response to high glucose and exendin-4 level.
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Affiliation(s)
- Dassine Berdous
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Xavier Berney
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Ana Rodriguez Sanchez-Archidona
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland; Vital-IT, Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland.
| | - Maxime Jan
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Clara Roujeau
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Isabel C Lopez-Mejia
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Randall Mynatt
- Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
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14
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Manceau R, Majeur D, Alquier T. Neuronal control of peripheral nutrient partitioning. Diabetologia 2020; 63:673-682. [PMID: 32030470 DOI: 10.1007/s00125-020-05104-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 12/20/2019] [Indexed: 12/16/2022]
Abstract
The appropriate utilisation, storage and conversion of nutrients in peripheral tissues, referred to as nutrient partitioning, is a fundamental process to adapt to nutritional and metabolic challenges and is thus critical for the maintenance of a healthy energy balance. Alterations in this process during nutrient excess can have deleterious effects on glucose and lipid homeostasis and contribute to the development of obesity and type 2 diabetes. Nutrient partitioning is a complex integrated process under the control of hormonal and neural signals. Neural control relies on the capacity of the brain to sense circulating metabolic signals and mount adaptive neuroendocrine and autonomic responses. This review aims to discuss the hypothalamic neurocircuits and molecular mechanisms controlling nutrient partitioning and their potential contribution to metabolic maladaptation and disease.
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Affiliation(s)
- Romane Manceau
- Montréal Diabetes Research Center and Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 rue Saint-Denis, Montréal, QC, H2X 0A9, Canada
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Danie Majeur
- Montréal Diabetes Research Center and Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 rue Saint-Denis, Montréal, QC, H2X 0A9, Canada
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Thierry Alquier
- Montréal Diabetes Research Center and Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 rue Saint-Denis, Montréal, QC, H2X 0A9, Canada.
- Department of Medicine, Université de Montréal, Montréal, QC, Canada.
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15
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Méquinion M, Foldi CJ, Andrews ZB. The Ghrelin-AgRP Neuron Nexus in Anorexia Nervosa: Implications for Metabolic and Behavioral Adaptations. Front Nutr 2020; 6:190. [PMID: 31998738 PMCID: PMC6962137 DOI: 10.3389/fnut.2019.00190] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 12/11/2019] [Indexed: 11/13/2022] Open
Abstract
Anorexia Nervosa (AN) is viewed as primarily a psychiatric disorder owing to the considerable behavioral and genetic overlap with mood disorders and other psychiatric traits. However, the recent reconceptualization of AN as one of both psychiatric and metabolic etiology suggests that metabolic circuits conveying hunger, or sensitive to signals of hunger, may be a critical nexus linking metabolic dysfunction to mood disturbances. Within the brain, hunger is primarily percieved by Agouti-related (AgRP) neurons and hunger increases plasma concentrations of the hormone ghrelin, which targets ghrelin receptors on AgRP neurons to facilitate metabolic adaptations to low energy availability. However, beyond the fundamental role in maintaining hunger signaling, AgRP neurons regulate a diverse range of behaviors such as motivation, locomotor activity, negative reinforcement, anxiety, and obsession and a key factor involved in the manifestation of these behavioral changes in response to activation is the presence or absence of food availability. These changes can be considered adaptive in that they promote affective food-seeking strategies in environments with limited food availability. However, it also suggests that these neurons, so well-studied for their metabolic control, shape mood-related behaviors in a context-dependent manner and dysfunctional control leads not only to metabolic problems but also potentially mood-related problems. The purpose of this review is to underline the potential role of AgRP neurons and ghrelin signaling in both the metabolic and behavioral changes observed in anorexia nervosa. We aim to highlight the most recent studies on AgRP neurons and ghrelin signaling and integrate their metabolic and behavioral roles in normal function and highlight how dysfunction may contribute to the development of AN.
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Affiliation(s)
| | | | - Zane B. Andrews
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, VIC, Australia
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16
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McGrath TM, Spreckley E, Rodriguez AF, Viscomi C, Alamshah A, Akalestou E, Murphy KG, Jones NS. The homeostatic dynamics of feeding behaviour identify novel mechanisms of anorectic agents. PLoS Biol 2019; 17:e3000482. [PMID: 31805040 PMCID: PMC6894749 DOI: 10.1371/journal.pbio.3000482] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 11/01/2019] [Indexed: 12/26/2022] Open
Abstract
Better understanding of feeding behaviour will be vital in reducing obesity and metabolic syndrome, but we lack a standard model that captures the complexity of feeding behaviour. We construct an accurate stochastic model of rodent feeding at the bout level in order to perform quantitative behavioural analysis. Analysing the different effects on feeding behaviour of peptide YY3-36 (PYY3-36), lithium chloride, glucagon-like peptide 1 (GLP-1), and leptin shows the precise behavioural changes caused by each anorectic agent. Our analysis demonstrates that the changes in feeding behaviour evoked by the anorectic agents investigated do not mimic the behaviour of well-fed animals and that the intermeal interval is influenced by fullness. We show how robust homeostatic control of feeding thwarts attempts to reduce food intake and how this might be overcome. In silico experiments suggest that introducing a minimum intermeal interval or modulating upper gut emptying can be as effective as anorectic drug administration.
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Affiliation(s)
- Thomas M. McGrath
- Department of Mathematics, Imperial College London, London, United Kingdom
- EPSRC Centre for the Mathematics of Precision Healthcare, Imperial College London, London, United Kingdom
| | - Eleanor Spreckley
- Section of Endocrinology and Investigative Medicine, Imperial College London, London, United Kingdom
| | - Aina Fernandez Rodriguez
- Section of Endocrinology and Investigative Medicine, Imperial College London, London, United Kingdom
| | - Carlo Viscomi
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Amin Alamshah
- Section of Endocrinology and Investigative Medicine, Imperial College London, London, United Kingdom
| | - Elina Akalestou
- Section of Endocrinology and Investigative Medicine, Imperial College London, London, United Kingdom
| | - Kevin G. Murphy
- Section of Endocrinology and Investigative Medicine, Imperial College London, London, United Kingdom
| | - Nick S. Jones
- Department of Mathematics, Imperial College London, London, United Kingdom
- EPSRC Centre for the Mathematics of Precision Healthcare, Imperial College London, London, United Kingdom
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17
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Hypothalamic neuronal circuits regulating hunger-induced taste modification. Nat Commun 2019; 10:4560. [PMID: 31594935 PMCID: PMC6783447 DOI: 10.1038/s41467-019-12478-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 09/09/2019] [Indexed: 01/20/2023] Open
Abstract
The gustatory system plays a critical role in sensing appetitive and aversive taste stimuli for evaluating food quality. Although taste preference is known to change depending on internal states such as hunger, a mechanistic insight remains unclear. Here, we examine the neuronal mechanisms regulating hunger-induced taste modification. Starved mice exhibit an increased preference for sweetness and tolerance for aversive taste. This hunger-induced taste modification is recapitulated by selective activation of orexigenic Agouti-related peptide (AgRP)-expressing neurons in the hypothalamus projecting to the lateral hypothalamus, but not to other regions. Glutamatergic, but not GABAergic, neurons in the lateral hypothalamus function as downstream neurons of AgRP neurons. Importantly, these neurons play a key role in modulating preferences for both appetitive and aversive tastes by using distinct pathways projecting to the lateral septum or the lateral habenula, respectively. Our results suggest that these hypothalamic circuits would be important for optimizing feeding behavior under fasting. Hunger modulates perception of good and bad tastes. Here, the authors report that orexigenic AgRP neurons in the hypothalamus mediate these effects through glutamatergic lateral hypothalamic neurons that send distinct projections to the lateral septum and lateral habenula.
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18
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Abstract
The gustatory system plays a critical role in sensing appetitive and aversive taste stimuli for evaluating food quality. Although taste preference is known to change depending on internal states such as hunger, a mechanistic insight remains unclear. Here, we examine the neuronal mechanisms regulating hunger-induced taste modification. Starved mice exhibit an increased preference for sweetness and tolerance for aversive taste. This hunger-induced taste modification is recapitulated by selective activation of orexigenic Agouti-related peptide (AgRP)-expressing neurons in the hypothalamus projecting to the lateral hypothalamus, but not to other regions. Glutamatergic, but not GABAergic, neurons in the lateral hypothalamus function as downstream neurons of AgRP neurons. Importantly, these neurons play a key role in modulating preferences for both appetitive and aversive tastes by using distinct pathways projecting to the lateral septum or the lateral habenula, respectively. Our results suggest that these hypothalamic circuits would be important for optimizing feeding behavior under fasting.
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19
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Laera L, Punzi G, Porcelli V, Gambacorta N, Trisolini L, Pierri CL, De Grassi A. CRAT missense variants cause abnormal carnitine acetyltransferase function in an early-onset case of Leigh syndrome. Hum Mutat 2019; 41:110-114. [PMID: 31448845 DOI: 10.1002/humu.23901] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 07/19/2019] [Accepted: 08/20/2019] [Indexed: 11/12/2022]
Abstract
Leigh syndrome, or subacute necrotizing encephalomyelopathy, is one of the most severe pediatric disorders of the mitochondrial energy metabolism. By performing whole-exome sequencing in a girl affected by Leigh syndrome and her parents, we identified two heterozygous missense variants (p.Tyr110Cys and p.Val569Met) in the carnitine acetyltransferase (CRAT) gene, encoding an enzyme involved in the control of mitochondrial short-chain acyl-CoA concentrations. Biochemical assays revealed carnitine acetyltransferase deficiency in the proband-derived fibroblasts. Functional analyses of recombinant-purified CRAT proteins demonstrated that both missense variants, located in the acyl-group binding site of the enzyme, severely impair its catalytic function toward acetyl-CoA, and the p.Val569Met variant also toward propionyl-CoA and octanoyl-CoA. Although a single recessive variant in CRAT has been recently associated with neurodegeneration with brain iron accumulation (NBIA), this study reports the first kinetic analysis of naturally occurring CRAT variants and demonstrates the genetic basis of carnitine acetyltransferase deficiency in a case of mitochondrial encephalopathy.
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Affiliation(s)
- Luna Laera
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
| | - Giuseppe Punzi
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
| | - Vito Porcelli
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
| | - Nicola Gambacorta
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
| | - Lucia Trisolini
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
| | - Ciro L Pierri
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
| | - Anna De Grassi
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
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20
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Wu CS, Bongmba OYN, Lee JH, Tuchaai E, Zhou Y, Li DP, Xue B, Chen Z, Sun Y. Ghrelin receptor in agouti-related peptide neurones regulates metabolic adaptation to calorie restriction. J Neuroendocrinol 2019; 31:e12763. [PMID: 31251830 PMCID: PMC7233797 DOI: 10.1111/jne.12763] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 06/24/2019] [Accepted: 06/25/2019] [Indexed: 12/16/2022]
Abstract
Ghrelin is a gut hormone that signals to the hypothalamus to stimulate growth hormone release, increase food intake and promote fat deposition. The ghrelin receptor, also known as growth hormone secretagogue receptor (GHS-R), is highly expressed in the brain, with the highest expression in agouti-related peptide (AgRP) neurones in the hypothalamus. Compelling evidence indicates that ghrelin serves as a survival hormone with respect to maintaining blood glucose and body weight during nutritional deficiencies. Recent studies have demonstrated that AgRP neurones are involved in metabolic and behavioural adaptation to an energy deficit to improve survival. In the present study, we used a neuronal subtype-specific GHS-R knockout mouse (AgRP-Cre;Ghsrf/f ) to investigate the role of GHS-R in hypothalamic AgRP neurones in metabolic and behavioural adaptation to hypocaloric restricted feeding. We subjected the mice to a restricted feeding regimen of 40% mild calorie restriction (CR), with one-quarter of food allotment given in the beginning of the light cycle and three-quarters given at the beginning of the dark cycle, to mimic normal mouse intake pattern. The CR-fed AgRP-Cre;Ghsrf/f mice exhibited reductions in body weight, fat mass and blood glucose. Metabolic profiling of these CR-fed AgRP-Cre;Ghsrf/f mice showed a trend toward reduced basal metabolic rate, significantly reduced core body temperature and a decreased expression of thermogenic genes in brown adipose tissue. This suggests a metabolic reset to a lower threshold. Significantly increased physical activity, a trend toward increased food anticipatory behaviour and altered fuel preferences were also observed in these mice. In addition, these CR-fed AgRP-Cre;Ghsrf/f mice exhibited a decreased counter-regulatory response, showing impaired hepatic glucose production. Lastly, hypothalamic gene expression in AgRP-Cre;Ghsrf/f mice revealed increased AgRP expression and a decreased expression of genes in β-oxidation pathways. In summary, our data suggest that GHS-R in AgRP neurones is a key component of the neurocircuitry involved in metabolic adaptation to calorie restriction.
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Affiliation(s)
- Chia-Shan Wu
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX, 77843, USA
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Odelia Y. N. Bongmba
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jong Han Lee
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
- College of Pharmacy, Gachon University, Incheon, 21936, Korea
| | - Ellie Tuchaai
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX, 77843, USA
| | - Yu Zhou
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China
| | - De-Pei Li
- Center for precision medicine, School of Medicine, University of Missouri. Columbia, MO 65212, USA
| | - Bingzhong Xue
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA
| | - Zheng Chen
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, TX 77030, USA
| | - Yuxiang Sun
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX, 77843, USA
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
- To whom correspondence should be addressed: Dr. Yuxiang Sun, mailing address: Department of Nutrition and Food Science, Texas A&M University, 214C Cater-Mattil, 2253 TAMU, College Station, TX 77843. Phone: 979-862-9143;
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21
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Cavalcanti-de-Albuquerque JP, Bober J, Zimmer MR, Dietrich MO. Regulation of substrate utilization and adiposity by Agrp neurons. Nat Commun 2019; 10:311. [PMID: 30659173 PMCID: PMC6338802 DOI: 10.1038/s41467-018-08239-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 12/20/2018] [Indexed: 12/17/2022] Open
Abstract
The type of nutrient utilized by the organism at any given time—substrate utilization—is a critical component of energy metabolism. The neuronal mechanisms involved in the regulation of substrate utilization in mammals are largely unknown. Here, we found that activation of hypothalamic Agrp neurons rapidly altered whole-body substrate utilization, increasing carbohydrate utilization, while decreasing fat utilization. These metabolic changes occurred even in the absence of caloric ingestion and were coupled to increased lipogenesis. Accordingly, inhibition of fatty acid synthase—a key enzyme that mediates lipogenesis—blunted the effects of Agrp neuron activation on substrate utilization. In pair-fed conditions during positive energy balance, activation of Agrp neurons improved metabolic efficiency, and increased weight gain and adiposity. Conversely, ablation of Agrp neurons impaired fat mass accumulation. These results suggest Agrp neurons regulate substrate utilization, contributing to lipogenesis and fat mass accumulation during positive energy balance. Agouti-related peptide (AgRP) producing neurons regulate food intake and metabolic processes in peripheral organs. Here, the authors show that hypothalamic AgRP neurons alter whole body substrate utilization to favour carbohydrate usage and lipid storage.
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Affiliation(s)
- João Paulo Cavalcanti-de-Albuquerque
- Department of Comparative Medicine, Yale University School of Medicine, 310 Cedar Street, Brady Memorial Laboratory Room 410, New Haven, CT, 06520, USA.,Institute of Biophysics Carlos Chagas Filho and of Nutrition Josue de Castro, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941, Brazil
| | - Jeremy Bober
- Department of Comparative Medicine, Yale University School of Medicine, 310 Cedar Street, Brady Memorial Laboratory Room 410, New Haven, CT, 06520, USA
| | - Marcelo R Zimmer
- Department of Comparative Medicine, Yale University School of Medicine, 310 Cedar Street, Brady Memorial Laboratory Room 410, New Haven, CT, 06520, USA.,Graduate Program in Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90035, Brazil
| | - Marcelo O Dietrich
- Department of Comparative Medicine, Yale University School of Medicine, 310 Cedar Street, Brady Memorial Laboratory Room 410, New Haven, CT, 06520, USA. .,Graduate Program in Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90035, Brazil. .,Department of Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA.
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22
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Lockie SH, Stark R, Mequinion M, Ch’ng S, Kong D, Spanswick DC, Lawrence AJ, Andrews ZB. Glucose Availability Predicts the Feeding Response to Ghrelin in Male Mice, an Effect Dependent on AMPK in AgRP Neurons. Endocrinology 2018; 159:3605-3614. [PMID: 30204871 PMCID: PMC6169619 DOI: 10.1210/en.2018-00536] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 09/05/2018] [Indexed: 01/31/2023]
Abstract
Metabolic feedback from the periphery to the brain results from a dynamic physiologic fluctuation of nutrients and hormones, including glucose and fatty acids, ghrelin, leptin, and insulin. The specific interactions between humoral factors and how they influence feeding is largely unknown. We hypothesized that acute glucose availability may alter how the brain responds to ghrelin, a hormonal signal of energy availability. Acute glucose administration suppressed a range of ghrelin-induced behaviors as well as gene expression changes in hypothalamic neuropeptide Y (NPY) and agouti-related peptide (AgRP) neurons after ghrelin administration. Knockdown of the energy-sensing molecule AMP-activated protein kinase (AMPK) in AgRP neurons resulted in loss of the glucose effect, and mice responded as though pretreated with saline. Conversely, 2-deoxyglucose (2-DG), which decreases glucose availability, potentiated ghrelin-induced feeding and increased hypothalamic NPY mRNA levels. AMPK knockdown did not alter the additive effect of 2-DG and ghrelin on feeding. Our findings support the idea that computation of energy status is dynamic, is informed by multiple signals, and responds to acute fluctuations in metabolic state. These observations are broadly relevant to the investigation of neuroendocrine control of feeding and highlight the underappreciated complexity of control within these systems.
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Affiliation(s)
- Sarah H Lockie
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Romana Stark
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Mathieu Mequinion
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Sarah Ch’ng
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Dong Kong
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts
- Program in Neuroscience, Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts
| | - David C Spanswick
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
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23
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Alvarsson A, Stanley SA. Remote control of glucose-sensing neurons to analyze glucose metabolism. Am J Physiol Endocrinol Metab 2018; 315:E327-E339. [PMID: 29812985 PMCID: PMC6171010 DOI: 10.1152/ajpendo.00469.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 04/25/2018] [Accepted: 05/23/2018] [Indexed: 12/13/2022]
Abstract
The central nervous system relies on a continual supply of glucose, and must be able to detect glucose levels and regulate peripheral organ functions to ensure that its energy requirements are met. Specialized glucose-sensing neurons, first described half a century ago, use glucose as a signal and modulate their firing rates as glucose levels change. Glucose-excited neurons are activated by increasing glucose concentrations, while glucose-inhibited neurons increase their firing rate as glucose concentrations fall and decrease their firing rate as glucose concentrations rise. Glucose-sensing neurons are present in multiple brain regions and are highly expressed in hypothalamic regions, where they are involved in functions related to glucose homeostasis. However, the roles of glucose-sensing neurons in healthy and disease states remain poorly understood. Technologies that can rapidly and reversibly activate or inhibit defined neural populations provide invaluable tools to investigate how specific neural populations regulate metabolism and other physiological roles. Optogenetics has high temporal and spatial resolutions, requires implants for neural stimulation, and is suitable for modulating local neural populations. Chemogenetics, which requires injection of a synthetic ligand, can target both local and widespread populations. Radio- and magnetogenetics offer rapid neural activation in localized or widespread neural populations without the need for implants or injections. These tools will allow us to better understand glucose-sensing neurons and their metabolism-regulating circuits.
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Affiliation(s)
- Alexandra Alvarsson
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai , New York, New York
| | - Sarah A Stanley
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai , New York, New York
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai , New York, New York
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24
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Targeting AgRP neurons to maintain energy balance: Lessons from animal models. Biochem Pharmacol 2018; 155:224-232. [PMID: 30012460 DOI: 10.1016/j.bcp.2018.07.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/12/2018] [Indexed: 01/19/2023]
Abstract
The current obesity epidemic is a major worldwide health and economic burden. In the modern environment, an increase in the intake of high-fat and high-sugar foods plays a crucial role in the development of obesity by disrupting the mechanisms governing food intake and energy balance. Food intake and whole-body energy balance are regulated by the central nervous system through a sophisticated neuronal network located mostly in the hypothalamus. In particular, the hypothalamic arcuate nucleus (ARC) is a fundamental center that senses hormonal and nutrient-related signals informing about the energy state of the organism. The ARC contains two small, defined populations of neurons with opposite functions: anorexigenic proopiomelanocortin (POMC)-expressing neurons and orexigenic Agouti-related protein (AgRP)-expressing neurons. AgRP neurons, which also co-produce neuropeptide Y (NPY) and γ-Aminobutyric acid (GABA), are involved in an increase in hunger and a decrease in energy expenditure. In this review, we summarize the key findings from the most common animal models targeting AgRP neurons and the tools used to discern the role of this specific neuronal population in the control of peripheral metabolism, appetite, feeding-related behavior, and other complex behaviors. We also discuss how knowledge gained from these studies has revealed new pathways and key proteins that could be potential therapeutic targets to reduce appetite and food addictions in obesity and other diseases.
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25
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Reichenbach A, Stark R, Mequinion M, Lockie SH, Lemus MB, Mynatt RL, Luquet S, Andrews ZB. Carnitine acetyltransferase (Crat) in hunger-sensing AgRP neurons permits adaptation to calorie restriction. FASEB J 2018; 32:fj201800634R. [PMID: 29932868 PMCID: PMC6219829 DOI: 10.1096/fj.201800634r] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 06/12/2018] [Indexed: 12/13/2022]
Abstract
Hunger-sensing agouti-related peptide (AgRP) neurons ensure survival by adapting metabolism and behavior to low caloric environments. This adaption is accomplished by consolidating food intake, suppressing energy expenditure, and maximizing fat storage (nutrient partitioning) for energy preservation. The intracellular mechanisms responsible are unknown. Here we report that AgRP carnitine acetyltransferase (Crat) knockout (KO) mice exhibited increased fatty acid utilization and greater fat loss after 9 d of calorie restriction (CR). No differences were seen in mice with ad libitum food intake. Eleven days ad libitum feeding after CR resulted in greater food intake, rebound weight gain, and adiposity in AgRP Crat KO mice compared with wild-type controls, as KO mice act to restore pre-CR fat mass. Collectively, this study highlights the importance of Crat in AgRP neurons to regulate nutrient partitioning and fat mass during chronically reduced caloric intake. The increased food intake, body weight gain, and adiposity in KO mice after CR also highlights the detrimental and persistent metabolic consequence of impaired substrate utilization associated with CR. This finding may have significant implications for postdieting weight management in patients with metabolic diseases.-Reichenbach, A., Stark, R., Mequinion, M., Lockie, S. H., Lemus, M. B., Mynatt, R. L., Luquet, S., Andrews, Z. B. Carnitine acetyltransferase (Crat) in hunger-sensing AgRP neurons permits adaptation to calorie restriction.
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Affiliation(s)
- Alex Reichenbach
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Romana Stark
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Mathieu Mequinion
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Sarah H. Lockie
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Moyra B. Lemus
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Randall L. Mynatt
- Gene Nutrient Interactions Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana, USA
- Transgenic Core Facility, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana, USA; and
| | - Serge Luquet
- Université of Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionelle et Adaptative, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche 8251, Paris, France
| | - Zane B. Andrews
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
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26
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Reichenbach A, Mequinion M, Bayliss JA, Lockie SH, Lemus MB, Mynatt RL, Stark R, Andrews ZB. Carnitine Acetyltransferase in AgRP Neurons Is Required for the Homeostatic Adaptation to Restricted Feeding in Male Mice. Endocrinology 2018; 159:2473-2483. [PMID: 29697769 PMCID: PMC6692886 DOI: 10.1210/en.2018-00131] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/19/2018] [Indexed: 12/14/2022]
Abstract
Behavioral adaptation to periods of varying food availability is crucial for survival, and agouti-related protein (AgRP) neurons have been associated with entrainment to temporal restricted feeding. We have shown that carnitine acetyltransferase (Crat) in AgRP neurons enables metabolic flexibility and appropriate nutrient partitioning. In this study, by restricting food availability to 3 h/d during the light phase, we examined whether Crat is a component of a food-entrainable oscillator (FEO) that helps link behavior to food availability. AgRP Crat knockout (KO) mice consumed less food and regained less body weight but maintained blood glucose levels during the 25-day restricted feeding protocol. Importantly, we observed no difference in meal latency, food anticipatory activity (FAA), or brown adipose tissue temperature during the first 13 days of restricted feeding. However, as the restricted feeding paradigm progressed, we noticed an increased FAA in AgRP Crat KO mice. The delayed increase in FAA, which developed during the last 12 days of restricted feeding, corresponded with elevated plasma levels of corticosterone and nonesterified fatty acids, indicating it resulted from greater energy debt incurred by KO mice over the course of the experiment. These experiments highlight the importance of Crat in AgRP neurons in regulating feeding behavior and body weight gain during restricted feeding but not in synchronizing behavior to food availability. Thus, Crat within AgRP neurons forms a component of the homeostatic response to restricted feeding but is not likely to be a molecular component of FEO.
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Affiliation(s)
- Alex Reichenbach
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Mathieu Mequinion
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Jacqueline A Bayliss
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Sarah H Lockie
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Moyra B Lemus
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Randall L Mynatt
- Gene Nutrient Interactions Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
- Transgenic Core Facility, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
| | - Romana Stark
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
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