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Ricci A, Rubino E, Serra GP, Wallén-Mackenzie Å. Concerning neuromodulation as treatment of neurological and neuropsychiatric disorder: Insights gained from selective targeting of the subthalamic nucleus, para-subthalamic nucleus and zona incerta in rodents. Neuropharmacology 2024; 256:110003. [PMID: 38789078 DOI: 10.1016/j.neuropharm.2024.110003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 04/26/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024]
Abstract
Neuromodulation such as deep brain stimulation (DBS) is advancing as a clinical intervention in several neurological and neuropsychiatric disorders, including Parkinson's disease, dystonia, tremor, and obsessive-compulsive disorder (OCD) for which DBS is already applied to alleviate severely afflicted individuals of symptoms. Tourette syndrome and drug addiction are two additional disorders for which DBS is in trial or proposed as treatment. However, some major remaining obstacles prevent this intervention from reaching its full therapeutic potential. Side-effects have been reported, and not all DBS-treated individuals are relieved of their symptoms. One major target area for DBS electrodes is the subthalamic nucleus (STN) which plays important roles in motor, affective and associative functions, with impact on for example movement, motivation, impulsivity, compulsivity, as well as both reward and aversion. The multifunctionality of the STN is complex. Decoding the anatomical-functional organization of the STN could enhance strategic targeting in human patients. The STN is located in close proximity to zona incerta (ZI) and the para-subthalamic nucleus (pSTN). Together, the STN, pSTN and ZI form a highly heterogeneous and clinically important brain area. Rodent-based experimental studies, including opto- and chemogenetics as well as viral-genetic tract tracings, provide unique insight into complex neuronal circuitries and their impact on behavior with high spatial and temporal precision. This research field has advanced tremendously over the past few years. Here, we provide an inclusive review of current literature in the pre-clinical research fields centered around STN, pSTN and ZI in laboratory mice and rats; the three highly heterogeneous and enigmatic structures brought together in the context of relevance for treatment strategies. Specific emphasis is placed on methods of manipulation and behavioral impact.
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Affiliation(s)
- Alessia Ricci
- Uppsala University, Department of Organism Biology, 756 32 Uppsala, Sweden; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Eleonora Rubino
- Uppsala University, Department of Organism Biology, 756 32 Uppsala, Sweden; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Gian Pietro Serra
- Uppsala University, Department of Organism Biology, 756 32 Uppsala, Sweden; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Åsa Wallén-Mackenzie
- Uppsala University, Department of Organism Biology, 756 32 Uppsala, Sweden; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA.
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Cai H, Schnapp WI, Mann S, Miscevic M, Shcmit MB, Conteras M, Fang C. Neural circuits regulation of satiation. Appetite 2024; 200:107512. [PMID: 38801994 PMCID: PMC11227400 DOI: 10.1016/j.appet.2024.107512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 05/21/2024] [Accepted: 05/22/2024] [Indexed: 05/29/2024]
Abstract
Terminating a meal after achieving satiation is a critical step in maintaining a healthy energy balance. Despite the extensive collection of information over the last few decades regarding the neural mechanisms controlling overall eating, the mechanism underlying different temporal phases of eating behaviors, especially satiation, remains incompletely understood and is typically embedded in studies that measure the total amount of food intake. In this review, we summarize the neural circuits that detect and integrate satiation signals to suppress appetite, from interoceptive sensory inputs to the final motor outputs. Due to the well-established role of cholecystokinin (CCK) in regulating the satiation, we focus on the neural circuits that are involved in regulating the satiation effect caused by CCK. We also discuss several general principles of how these neural circuits control satiation, as well as the limitations of our current understanding of the circuits function. With the application of new techniques involving sophisticated cell-type-specific manipulation and mapping, as well as real-time recordings, it is now possible to gain a better understanding of the mechanisms specifically underlying satiation.
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Affiliation(s)
- Haijiang Cai
- Department of Neuroscience, University of Arizona, Tucson, AZ, 85721, USA; Bio 5 Institute and Department of Neurology, University of Arizona, Tucson, AZ, 85721, USA.
| | - Wesley I Schnapp
- Department of Neuroscience, University of Arizona, Tucson, AZ, 85721, USA; Graduate Interdisciplinary Program in Neuroscience, University of Arizona, Tucson, AZ, 85721, USA
| | - Shivani Mann
- Department of Neuroscience, University of Arizona, Tucson, AZ, 85721, USA
| | - Masa Miscevic
- Department of Neuroscience, University of Arizona, Tucson, AZ, 85721, USA; Graduate Interdisciplinary Program in Physiological Sciences, University of Arizona, Tucson, AZ, 85721, USA
| | - Matthew B Shcmit
- Department of Neuroscience, University of Arizona, Tucson, AZ, 85721, USA; Graduate Interdisciplinary Program in Neuroscience, University of Arizona, Tucson, AZ, 85721, USA
| | - Marco Conteras
- Department of Neuroscience, University of Arizona, Tucson, AZ, 85721, USA
| | - Caohui Fang
- Department of Neuroscience, University of Arizona, Tucson, AZ, 85721, USA
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Saito S, Hashimoto H, Wakashin H, Ishibane M, Pae S, Saito S, Reien Y, Hirayama Y, Seo Y, Mizushima T, Anzai N. Central administered xenin induced Fos expression in nesfatin-1 neurons in rats. Brain Res Bull 2023; 204:110788. [PMID: 37844783 DOI: 10.1016/j.brainresbull.2023.110788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 10/03/2023] [Accepted: 10/13/2023] [Indexed: 10/18/2023]
Abstract
Xenin is a 25-amino acid peptide identified in human gastric mucosa, which is widely expressed in peripheral and central tissues. It is known that the central or peripheral administration of xenin decreases food intake in rodents. Nesfatin-1/NUCB2 (nesfatin-1) has been identified as an anorexic neuropeptide, it is often found co-localized with many peptides in the central nervous system. After the intracerebroventricular administration of xenin on nesfain-1-like immunoreactivity (LI) neurons, we examined its effects on food intake and water intake in rats. As a result, Fos-LI neurons were observed in the organum vasculosum of the laminae terminalis (OVLT), the median preoptic nucleus (MnPO), the subfornical organ (SFO), the supraoptic nucleus (SON), the paraventricular nucleus (PVN), the arcuate nucleus (Arc), the lateral hypothalamic area (LHA), the central amygdaloid nucleus (CAN), the dorsal raphe nucleus (DR), the locus coeruleus (LC), the area postrema (AP) and the nucleus of the solitary tract (NTS). After the administration, the number of Fos-LI neurons was significantly increased in the LC and the OVLT, the MnPO, the SFO, the SON, the PVN, the Arc, the LHA, the CAN, the DR, the AP and the NTS, compared with the control group. After the administration of xenin, we conducted double immunohistochemistry for Fos and nesfatin-1, and found that the number of nesfatin-1-LI neurons expressing Fos were significantly increased in the SON, the PVN, the Arc, the LHA, the CAN, the DR, the AP and the NTS, compared with the control group. The pretreatment of nesfatin-1 antisense significantly attenuated this xenin-induced feeding suppression, while that of nesfatin-1 missense showed no improvement. These results indicate that central administered xenin may have anorexia effects associated with activated central nesfatin-1 neurons.
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Affiliation(s)
- Shota Saito
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba 260-8670, JAPAN; Department of Rehabilitation, Dokkyo Medical University, 8880 Kitakobayashi, Mibu, Shimotsugagun, Tochigi 321-0293, Japan
| | - Hirofumi Hashimoto
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba 260-8670, JAPAN; Department of Rehabilitation, Dokkyo Medical University, 8880 Kitakobayashi, Mibu, Shimotsugagun, Tochigi 321-0293, Japan; Department of Regulatory Physiology, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Shimotsugagun, Tochigi 321-0293, Japan.
| | - Hidefumi Wakashin
- Department of Regulatory Physiology, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Shimotsugagun, Tochigi 321-0293, Japan
| | - Misaki Ishibane
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba 260-8670, JAPAN
| | - Sangjon Pae
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba 260-8670, JAPAN
| | - Shinpei Saito
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba 260-8670, JAPAN
| | - Yoshie Reien
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba 260-8670, JAPAN
| | - Yuri Hirayama
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba 260-8670, JAPAN
| | - Yoshiteru Seo
- Department of Regulatory Physiology, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Shimotsugagun, Tochigi 321-0293, Japan; Division of Cell Structure, National Institute for Physiological Sciences, Okazaki, Aichi 444-8787, Japan
| | - Takashi Mizushima
- Department of Rehabilitation, Dokkyo Medical University, 8880 Kitakobayashi, Mibu, Shimotsugagun, Tochigi 321-0293, Japan
| | - Naohiko Anzai
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba 260-8670, JAPAN
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Roh E, Choi KM. Hormonal Gut-Brain Signaling for the Treatment of Obesity. Int J Mol Sci 2023; 24:ijms24043384. [PMID: 36834794 PMCID: PMC9959457 DOI: 10.3390/ijms24043384] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 02/10/2023] Open
Abstract
The brain, particularly the hypothalamus and brainstem, monitors and integrates circulating metabolic signals, including gut hormones. Gut-brain communication is also mediated by the vagus nerve, which transmits various gut-derived signals. Recent advances in our understanding of molecular gut-brain communication promote the development of next-generation anti-obesity medications that can safely achieve substantial and lasting weight loss comparable to metabolic surgery. Herein, we comprehensively review the current knowledge about the central regulation of energy homeostasis, gut hormones involved in the regulation of food intake, and clinical data on how these hormones have been applied to the development of anti-obesity drugs. Insight into and understanding of the gut-brain axis may provide new therapeutic perspectives for the treatment of obesity and diabetes.
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Affiliation(s)
- Eun Roh
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang 14068, Republic of Korea
| | - Kyung Mook Choi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University College of Medicine, Seoul 02841, Republic of Korea
- Correspondence: or
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Lutz TA. Creating the amylin story. Appetite 2022; 172:105965. [DOI: 10.1016/j.appet.2022.105965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/28/2022] [Accepted: 02/04/2022] [Indexed: 02/07/2023]
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Boccia L, Borner T, Ghidewon MY, Kulka P, Piffaretti C, Doebley SA, De Jonghe BC, Grill HJ, Lutz TA, Le Foll C. Hypophagia induced by salmon calcitonin, but not by amylin, is partially driven by malaise and is mediated by CGRP neurons. Mol Metab 2022; 58:101444. [PMID: 35091058 PMCID: PMC8873943 DOI: 10.1016/j.molmet.2022.101444] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/07/2022] [Accepted: 01/19/2022] [Indexed: 11/29/2022] Open
Abstract
Objective The behavioral mechanisms and the neuronal pathways mediated by amylin and its long-acting analog sCT (salmon calcitonin) are not fully understood and it is unclear to what extent sCT and amylin engage overlapping or distinct neuronal subpopulations to reduce food intake. We here hypothesize that amylin and sCT recruit different neuronal population to mediate their anorectic effects. Methods Viral approaches were used to inhibit calcitonin gene-related peptide (CGRP) lateral parabrachial nucleus (LPBN) neurons and assess their role in amylin’s and sCT’s ability to decrease food intake in mice. In addition, to test the involvement of LPBN CGRP neuropeptidergic signaling in the mediation of amylin and sCT’s effects, a LPBN site-specific knockdown was performed in rats. To deeper investigate whether the greater anorectic effect of sCT compared to amylin is due do the recruitment of additional neuronal pathways related to malaise multiple and distinct animal models tested whether amylin and sCT induce conditioned avoidance, nausea, emesis, and conditioned affective taste aversion. Results Our results indicate that permanent or transient inhibition of CGRP neurons in LPBN blunts sCT-, but not amylin-induced anorexia and neuronal activation. Importantly, sCT but not amylin induces behaviors indicative of malaise including conditioned affective aversion, nausea, emesis, and conditioned avoidance; the latter mediated by CGRPLPBN neurons. Conclusions Together, the present study highlights that although amylin and sCT comparably decrease food intake, sCT is distinctive from amylin in the activation of anorectic neuronal pathways associated with malaise. CGRP neurons mediate the effect of the amylin agonist salmon calcitonin (sCT) on food intake. Amylin's hypophagic effect does not require CGRP neurons. sCT-induced anorexia but not amylin is associated with malaise.
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Affiliation(s)
- Lavinia Boccia
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich (UZH), 8057, Zurich, Switzerland
| | - Tito Borner
- Department of Biobehavioral Health Sciences, University of Pennsylvania, School of Nursing, Philadelphia, PA 19104, United States; Department of Psychiatry, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, United States
| | - Misgana Y Ghidewon
- Institute of Diabetes, Obesity and Metabolism and School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Patricia Kulka
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich (UZH), 8057, Zurich, Switzerland
| | - Chiara Piffaretti
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich (UZH), 8057, Zurich, Switzerland
| | - Sarah A Doebley
- Department of Biobehavioral Health Sciences, University of Pennsylvania, School of Nursing, Philadelphia, PA 19104, United States
| | - Bart C De Jonghe
- Department of Biobehavioral Health Sciences, University of Pennsylvania, School of Nursing, Philadelphia, PA 19104, United States; Department of Psychiatry, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, United States
| | - Harvey J Grill
- Institute of Diabetes, Obesity and Metabolism and School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Thomas A Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich (UZH), 8057, Zurich, Switzerland
| | - Christelle Le Foll
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich (UZH), 8057, Zurich, Switzerland.
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Müller TD, Blüher M, Tschöp MH, DiMarchi RD. Anti-obesity drug discovery: advances and challenges. Nat Rev Drug Discov 2022; 21:201-223. [PMID: 34815532 PMCID: PMC8609996 DOI: 10.1038/s41573-021-00337-8] [Citation(s) in RCA: 345] [Impact Index Per Article: 172.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2021] [Indexed: 12/27/2022]
Abstract
Enormous progress has been made in the last half-century in the management of diseases closely integrated with excess body weight, such as hypertension, adult-onset diabetes and elevated cholesterol. However, the treatment of obesity itself has proven largely resistant to therapy, with anti-obesity medications (AOMs) often delivering insufficient efficacy and dubious safety. Here, we provide an overview of the history of AOM development, focusing on lessons learned and ongoing obstacles. Recent advances, including increased understanding of the molecular gut-brain communication, are inspiring the pursuit of next-generation AOMs that appear capable of safely achieving sizeable and sustained body weight loss.
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Affiliation(s)
- Timo D. Müller
- grid.4567.00000 0004 0483 2525Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany ,grid.452622.5German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Matthias Blüher
- grid.411339.d0000 0000 8517 9062Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Leipzig, Germany
| | - Matthias H. Tschöp
- grid.4567.00000 0004 0483 2525Helmholtz Zentrum München, Neuherberg, Germany ,grid.6936.a0000000123222966Division of Metabolic Diseases, Department of Medicine, Technische Universität München, München, Germany
| | - Richard D. DiMarchi
- grid.411377.70000 0001 0790 959XDepartment of Chemistry, Indiana University, Bloomington, IN USA
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Sanchez MR, Wang Y, Cho TS, Schnapp WI, Schmit MB, Fang C, Cai H. Dissecting a disynaptic central amygdala - parasubthalamic nucleus neural circuit that mediates cholecystokinin-induced eating suppression. Mol Metab 2022; 58:101443. [PMID: 35066159 PMCID: PMC8844644 DOI: 10.1016/j.molmet.2022.101443] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/09/2022] [Accepted: 01/13/2022] [Indexed: 11/28/2022] Open
Abstract
Objective Cholecystokinin (CCK) plays a critical role in regulating eating and metabolism. Previous studies have mapped a multi-synapse neural pathway from the vagus nerve to the central nucleus of the amygdala (CEA) that mediates the anorexigenic effect of CCK. However, the neural circuit downstream of the CEA is still unknown due to the complexity of the neurons in the CEA. Here we sought to determine this circuit using a novel approach. Methods It has been established that a specific population of CEA neurons, marked by protein kinase C-delta (PKC-δ), mediates the anorexigenic effect of CCK by inhibiting other CEA inhibitory neurons. Taking advantage of this circuit, we dissected the neural circuit using a unique approach based on the idea that neurons downstream of the CEA should be disinhibited by CEAPKC-δ+ neurons while being activated by CCK. We also used optogenetic assisted electrophysiology circuit mapping and in vivo chemogenetic manipulation methods to determine the circuit structure and function. Results We found that neurons in the parasubthalamic nucleus (PSTh) are activated by the activation of CEAPKC-δ+ neurons and by the peripheral administration of CCK. We demonstrated that CEAPKC-δ+ neurons inhibit the PSTh-projecting CEA neurons; accordingly, the PSTh neurons can be disynaptically disinhibited or “activated” by CEAPKC-δ+ neurons. Finally, we showed that chemogenetic silencing of the PSTh neurons effectively attenuates the eating suppression induced by CCK. Conclusions Our results identified a disynaptic CEA-PSTh neural circuit that mediates the anorexigenic effect of CCK and thus provide an important neural mechanism of how CCK suppresses eating. A unique approach combining a genetically identified neuron population with an anorexigenic agent for circuits mapping. Dissected a disynaptic central amygdala-parasubthalamic nucleus neural circuit for the function of cholecystokinin. Identified a previously understudied brain region that regulates the anorexigenic effect of cholecystokinin.
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Affiliation(s)
| | - Yong Wang
- Department of Neuroscience, University of Arizona, Tucson, AZ, USA; Department of Physiology and Pathophysiology, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, PR China
| | - Tiffany S Cho
- Department of Neuroscience, University of Arizona, Tucson, AZ, USA
| | - Wesley I Schnapp
- Department of Neuroscience, University of Arizona, Tucson, AZ, USA; Graduate Interdisciplinary Program in Neuroscience, University of Arizona, Tucson, AZ, USA
| | - Matthew B Schmit
- Department of Neuroscience, University of Arizona, Tucson, AZ, USA; Graduate Interdisciplinary Program in Neuroscience, University of Arizona, Tucson, AZ, USA
| | - Caohui Fang
- Department of Neuroscience, University of Arizona, Tucson, AZ, USA
| | - Haijiang Cai
- Department of Neuroscience, University of Arizona, Tucson, AZ, USA; Bio5 Institute and Department of Neurology, University of Arizona, Tucson, AZ, USA.
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Sustained microglial activation in the area postrema of collagen-induced arthritis mice. Arthritis Res Ther 2021; 23:273. [PMID: 34715926 PMCID: PMC8556992 DOI: 10.1186/s13075-021-02657-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 10/12/2021] [Indexed: 02/07/2023] Open
Abstract
Background Central nervous system (CNS)-mediated symptoms, such as fatigue, depression, and hyperalgesia, are common complications among patients with rheumatoid arthritis (RA). However, it remains unclear how the peripheral pathology of RA spreads to the brain. Accumulated evidence showing an association between serum cytokine levels and aberrant CNS function suggests that humoral factors participate in this mechanism. In contrast to the well-known early responses of microglia (CNS-resident immune cells) in the area postrema [AP; a brain region lacking a blood–brain barrier (BBB)] to experimental inflammation, microglial alterations in the AP during chronic inflammation like RA remain unclear. Therefore, to determine whether microglia in the AP can react to persistent autoimmune-arthritis conditions, we analyzed these cells in a mouse model of collagen-induced arthritis (CIA). Methods Microglial number and morphology were analyzed in the AP of CIA and control mice (administered Freund’s adjuvant or saline). Immunostaining for ionized calcium-binding adaptor molecule-1 was performed at various disease phases: “pre-onset” [post-immunization day (PID) 21], “establishment” (PID 35), and “chronic” (PID 56 and 84). Quantitative analyses of microglial number and morphology were performed, with principal component analysis used to classify microglia. Interleukin-1β (IL-1β) mRNA expression was analyzed by multiple fluorescent in situ hybridization and real-time polymerase chain reaction. Behavioral changes were assessed by sucrose preference test. Results Microglia in the AP significantly increased in density and exhibited changes in morphology during the establishment and chronic phases, but not the pre-onset phase. Non-subjective clustering classification of cell morphology (CIA, 1,256 cells; saline, 852 cells) showed that the proportion of highly activated microglia increased in the CIA group during establishment and chronic phases. Moreover, the density of IL-1β-positive microglia, a hallmark of functional activation, was increased in the AP. Sucrose preferences in CIA mice negatively correlated with IL-1β expression in brain regions containing the AP. Conclusions Our findings demonstrate that microglia in the AP can sustain their activated state during persistent autoimmune arthritis, which suggests that chronic inflammation, such as RA, may affect microglia in brain regions lacking a BBB and have various neural consequences. Supplementary Information The online version contains supplementary material available at 10.1186/s13075-021-02657-x.
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Kern KA, DiBrog AM, Przybysz JT, Mietlicki-Baase EG. Effects of pramlintide on energy intake and food preference in rats given a choice diet. Physiol Behav 2021; 240:113541. [PMID: 34332974 DOI: 10.1016/j.physbeh.2021.113541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 07/22/2021] [Accepted: 07/23/2021] [Indexed: 10/20/2022]
Abstract
Amylin is a peptide hormone involved in the control of energy balance, making the amylin system a potential target for pharmacotherapies to treat obesity. Pramlintide, an amylin analogue, is an FDA-approved medication for the treatment of diabetes that also has food intake- and body weight-suppressive effects. However, it is unknown whether pramlintide may preferentially reduce intake of highly palatable, energy dense food, the overconsumption of which is thought to play a role in the etiology of obesity. Here, we investigate the effects of pramlintide on food intake and body weight in rats given a choice of chow and high fat diet (HFD). Systemic pramlintide injection in rats reduced HFD intake at 3h post-injection, with no effects at other times and no significant effects on chow intake, body weight, or percent preference for HFD. In a separate experiment, the effects of central injection of pramlintide on food intake and body weight were similarly evaluated. Intracerebroventricular pramlintide significantly reduced HFD intake throughout the 24h post-injection, with some suppressive effects on chow intake, and also decreased 24h body weight change. Again, no significant changes were observed in the proportion of calories obtained from HFD. The same intracerebroventricular doses of pramlintide did not induce pica, suggesting that pramlintide-mediated reductions in feeding are not due to nausea/malaise. Our results suggest that pramlintide reduces food intake in rats largely via reductions in intake of HFD versus chow, supporting the idea that the potent effects of pramlintide on palatable food intake may have utility in the treatment of obesity.
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Affiliation(s)
- Katherine A Kern
- Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - Adrianne M DiBrog
- Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - Johnathan T Przybysz
- Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - Elizabeth G Mietlicki-Baase
- Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, NY 14214, USA; Center for Ingestive Behavior Research, University at Buffalo, State University of New York, Buffalo, NY 14214, USA.
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Skovbjerg G, Roostalu U, Hansen HH, Lutz TA, Le Foll C, Salinas CG, Skytte JL, Jelsing J, Vrang N, Hecksher-Sørensen J. Whole-brain mapping of amylin-induced neuronal activity in receptor activity-modifying protein 1/3 knockout mice. Eur J Neurosci 2021; 54:4154-4166. [PMID: 33905587 DOI: 10.1111/ejn.15254] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 03/08/2021] [Accepted: 04/16/2021] [Indexed: 09/29/2022]
Abstract
The pancreatic hormone amylin plays a central role in regulating energy homeostasis and glycaemic control by stimulating satiation and reducing food reward, making amylin receptor agonists attractive for the treatment of metabolic diseases. Amylin receptors consist of heterodimerized complexes of the calcitonin receptor and receptor-activity modifying proteins subtype 1-3 (RAMP1-3). Neuronal activation in response to amylin dosing has been well characterized, but only in selected regions expressing high levels of RAMPs. The current study identifies global brain-wide changes in response to amylin and by comparing wild type and RAMP1/3 knockout mice reveals the importance of RAMP1/3 in mediating this response. Amylin dosing resulted in neuronal activation as measured by an increase in c-Fos labelled cells in 20 brain regions, altogether making up the circuitry of neuronal appetite regulation (e.g., area postrema (AP), nucleus of the solitary tract (NTS), parabrachial nucleus (PB), and central amygdala (CEA)). c-Fos response was also detected in distinct nuclei across the brain that typically have not been linked with amylin signalling. In RAMP1/3 knockout amylin induced low-level neuronal activation in seven regions, including the AP, NTS and PB, indicating the existence of RAMP1/3-independent mechanisms of amylin response. Under basal conditions RAMP1/3 knockout mice show reduced neuronal activity in the hippocampal formation as well as reduced hippocampal volume, suggesting a role for RAMP1/3 in hippocampal physiology and maintenance. Altogether these data provide a global map of amylin response in the mouse brain and establishes the significance of RAMP1/3 receptors in relaying this response.
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Affiliation(s)
| | | | | | - Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich, Vetsuisse Faculty University of Zurich, Zurich, Switzerland
| | - Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, Vetsuisse Faculty University of Zurich, Zurich, Switzerland
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12
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Boccia L, Gamakharia S, Coester B, Whiting L, Lutz TA, Le Foll C. Amylin brain circuitry. Peptides 2020; 132:170366. [PMID: 32634450 DOI: 10.1016/j.peptides.2020.170366] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 12/14/2022]
Abstract
Amylin is a peptide hormone that is mainly known to be produced by pancreatic β-cells in response to a meal but amylin is also produced by brain cells in discrete brain areas albeit in a lesser amount. Amylin receptor (AMY) is composed of the calcitonin core-receptor (CTR) and one of the 3 receptor activity modifying protein (RAMP), thus forming AMY1-3; RAMP enhances amylin binding properties to the CTR. However, amylin receptor agonist such as salmon calcitonin is able to bind CTR alone. Peripheral amylin's main binding site is located in the area postrema (AP) which then propagate the signal to the nucleus of the solitary tract and lateral parabrachial nucleus (LPBN) and it is then transmitted to the forebrain areas such as central amygdala and bed nucleus of the stria terminalis. Amylin's activation of these different brain areas mediates eating and other metabolic pathways controlling energy expenditure and glucose homeostasis. Peripheral amylin can also bind in the arcuate nucleus of the hypothalamus where it acts independently of the AP to activate POMC and NPY neurons. Amylin activation of NPY neurons has been shown to be transmitted to LPBN neurons to act on eating while amylin POMC signaling affects energy expenditure and locomotor activity. While a large amount of experiments have already been conducted, future studies will have to further investigate how amylin is taken up by forebrain areas and deepen our understanding of amylin action on peripheral metabolism.
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Affiliation(s)
- Lavinia Boccia
- Institute of Veterinary Physiology, University of Zurich, CH-8057, Zurich, Switzerland
| | - Salome Gamakharia
- Institute of Veterinary Physiology, University of Zurich, CH-8057, Zurich, Switzerland
| | - Bernd Coester
- Institute of Veterinary Physiology, University of Zurich, CH-8057, Zurich, Switzerland
| | - Lynda Whiting
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Australia
| | - Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich, CH-8057, Zurich, Switzerland
| | - Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, CH-8057, Zurich, Switzerland.
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13
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Boccia L, Le Foll C, Lutz TA. Noradrenaline signaling in the LPBN mediates amylin's and salmon calcitonin's hypophagic effect in male rats. FASEB J 2020; 34:15448-15461. [PMID: 32985027 DOI: 10.1096/fj.202001456rrr] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 09/07/2020] [Accepted: 09/10/2020] [Indexed: 11/11/2022]
Abstract
The LPBN (lateral parabrachial nucleus) plays an important role in feeding control. CGRP (calcitonin gene-related peptide) LPBN neurons activation mediates the anorectic effects of different gut-derived peptides, including amylin. Amylin and its long acting analog sCT (salmon calcitonin) exert their anorectic actions primarily by directly activating neurons located in the area postrema (AP). A large proportion of projections from the AP and the adjacent nucleus of the solitary tractNTS to the LPBN, are noradrenergic (NA), and amylin-activated NAAP neurons are critical in mediating amylin's hypophagic effects. Here, we determine the functional role of NAAP amylin activated neurons to activate CGRP and non-CGRP LPBN neurons. To this end, NA was specifically depleted in the rat LPBN through a stereotaxic microinfusion of 6-OHDA, a neurotoxic agent that destroys NA terminals. While amylin (50 μg/kg) and sCT (5 μg/kg) reduced eating in sham-lesioned rats, no reduction in feeding occurred in NA-depleted animals. Further, the amylin-induced c-Fos response in the LPBN and c-Fos/CGRP colocalization were reduced in NA-depleted animals compared to controls. We conclude that AP → LPBN NA signaling, through the activation of LPBN CGRP neurons, mediates part of amylin's hypophagic effect.
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Affiliation(s)
- Lavinia Boccia
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
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14
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Distributed amylin receptor signaling and its influence on motivated behavior. Physiol Behav 2020; 222:112958. [DOI: 10.1016/j.physbeh.2020.112958] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/11/2020] [Accepted: 04/30/2020] [Indexed: 12/11/2022]
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15
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Foll CL, Lutz TA. Systemic and Central Amylin, Amylin Receptor Signaling, and Their Physiological and Pathophysiological Roles in Metabolism. Compr Physiol 2020; 10:811-837. [PMID: 32941692 DOI: 10.1002/cphy.c190034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This article in the Neural and Endocrine Section of Comprehensive Physiology discusses the physiology and pathophysiology of the pancreatic hormone amylin. Shortly after its discovery in 1986, amylin has been shown to reduce food intake as a satiation signal to limit meal size. Amylin also affects food reward, sensitizes the brain to the catabolic actions of leptin, and may also play a prominent role in the development of certain brain areas that are involved in metabolic control. Amylin may act at different sites in the brain in addition to the area postrema (AP) in the caudal hindbrain. In particular, the sensitizing effect of amylin on leptin action may depend on a direct interaction in the hypothalamus. The concept of central pathways mediating amylin action became more complex after the discovery that amylin is also synthesized in certain hypothalamic areas but the interaction between central and peripheral amylin signaling remains currently unexplored. Amylin may also play a dominant pathophysiological role that is associated with the aggregation of monomeric amylin into larger, cytotoxic molecular entities. This aggregation in certain species may contribute to the development of type 2 diabetes mellitus but also cardiovascular disease. Amylin receptor pharmacology is complex because several distinct amylin receptor subtypes have been described, because other neuropeptides [e.g., calcitonin gene-related peptide (CGRP)] can also bind to amylin receptors, and because some components of the functional amylin receptor are also used for other G-protein coupled receptor (GPCR) systems. © 2020 American Physiological Society. Compr Physiol 10:811-837, 2020.
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Affiliation(s)
- Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
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16
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Viral depletion of calcitonin receptors in the area postrema: A proof-of-concept study. Physiol Behav 2020; 223:112992. [PMID: 32497530 DOI: 10.1016/j.physbeh.2020.112992] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 05/06/2020] [Accepted: 05/27/2020] [Indexed: 01/12/2023]
Abstract
The area postrema (AP), located in the caudal hindbrain, is one of the primary binding sites for the endocrine satiation hormone amylin. Amylin is co-secreted with insulin from pancreatic ß-cells and binds to heterodimeric receptors that consist of a calcitonin core receptor (CTR) paired with receptor-activity modifying protein (RAMP) 1 or 3. In this study, we aim to validate a CTR-floxed (CTRfl/fl) mouse model for the functional and site-specific depletion of amylin/CTR signaling in the AP and the nucleus tractus solitarius (NTS). CTRfl/fl mice were injected in the NTS with adeno-associated virus (AAV) containing a green fluorescent protein tag (GFP) and Cre recombinase to create a locally restricted knockout of CTR in the caudal hindbrain. KO mice showed a lack of c-Fos expression, a marker for neuronal activation, in the AP, NTS and LPBN after amylin injection. The effect of amylin and salmon calcitonin (sCT), an amylin receptor agonist, on food intake was blunted in KO mice, confirming a functional reduction of amylin signaling in the hindbrain.
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17
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Coester B, Koester-Hegmann C, Lutz TA, Le Foll C. Amylin/Calcitonin Receptor-Mediated Signaling in POMC Neurons Influences Energy Balance and Locomotor Activity in Chow-Fed Male Mice. Diabetes 2020; 69:1110-1125. [PMID: 32152204 DOI: 10.2337/db19-0849] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 02/28/2020] [Indexed: 11/13/2022]
Abstract
Amylin, a pancreatic hormone and neuropeptide, acts principally in the hindbrain to decrease food intake and has recently been shown to act as a neurotrophic factor to control the development of area postrema → nucleus of the solitary tract and arcuate hypothalamic nucleus → paraventricular nucleus axonal fiber outgrowth. Amylin is also able to activate ERK signaling specifically in POMC neurons independently of leptin. For investigation of the physiological role of amylin signaling in POMC neurons, the core component of the amylin receptor, calcitonin receptor (CTR), was depleted from POMC neurons using an inducible mouse model. The loss of CTR in POMC neurons leads to increased body weight gain, increased adiposity, and glucose intolerance in male knockout mice, characterized by decreased energy expenditure (EE) and decreased expression of uncoupling protein 1 (UCP1) in brown adipose tissue. Furthermore, a decreased spontaneous locomotor activity and absent thermogenic reaction to the application of the amylin receptor agonist were observed in male and female mice. Together, these results show a significant physiological impact of amylin/calcitonin signaling in CTR-POMC neurons on energy metabolism and demonstrate the need for sex-specific approaches in obesity research and potentially treatment.
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Affiliation(s)
- Bernd Coester
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | | | - Thomas A Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Christelle Le Foll
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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18
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Zakariassen HL, John LM, Lutz TA. Central control of energy balance by amylin and calcitonin receptor agonists and their potential for treatment of metabolic diseases. Basic Clin Pharmacol Toxicol 2020; 127:163-177. [PMID: 32363722 DOI: 10.1111/bcpt.13427] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/28/2020] [Accepted: 04/28/2020] [Indexed: 12/13/2022]
Abstract
The prevalence of obesity and associated comorbidities such as type 2 diabetes and cardiovascular disease is increasing globally. Body-weight loss reduces the risk of morbidity and mortality in obese individuals, and thus, pharmacotherapies that induce weight loss can be of great value in improving the health and well-being of people living with obesity. Treatment with amylin and calcitonin receptor agonists reduces food intake and induces weight loss in several animal models, and a number of companies have started clinical testing for peptide analogues in the treatment of obesity and/or type 2 diabetes. Studies predominantly performed in rodent models show that amylin and the dual amylin/calcitonin receptor agonist salmon calcitonin achieve their metabolic effects by engaging areas in the brain associated with regulating homeostatic energy balance. In particular, signalling via neuronal circuits in the caudal hindbrain and the hypothalamus is implicated in mediating effects on food intake and energy expenditure. We review the current literature investigating the interaction of amylin/calcitonin receptor agonists with neurocircuits that induce the observed metabolic effects. Moreover, the status of drug development of amylin and calcitonin receptor agonists for the treatment of metabolic diseases is summarized.
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Affiliation(s)
- Hannah Louise Zakariassen
- Section of Experimental Animal Models, Department of Veterinary and Animal Science, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark.,Obesity Pharmacology, Novo Nordisk A/S, Måløv, Denmark
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19
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Maske CB, Coiduras II, Ondriezek ZE, Terrill SJ, Williams DL. Intermittent High-Fat Diet Intake Reduces Sensitivity to Intragastric Nutrient Infusion and Exogenous Amylin in Female Rats. Obesity (Silver Spring) 2020; 28:942-952. [PMID: 32237211 PMCID: PMC7180114 DOI: 10.1002/oby.22779] [Citation(s) in RCA: 3] [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: 09/17/2019] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Intermittent (INT) access to a high-fat diet (HFD) can induce excessive-intake phenotypes in rodents. This study hypothesized that impaired satiation responses contribute to elevated intake in an INT-HFD access model. METHODS First, this study characterized the intake and meal patterns of female rats that were subjected to an INT HFD in which a 45% HFD was presented for 20 hours every fourth day. To examine nutrient-induced satiation, rats received intragastric infusions of saline or Ensure Plus prior to darkness-onset food access. A similar design was used to examine sensitivity to the satiating effect of amylin. This study then examined whether an INT HFD influences amylin-induced c-Fos in feeding-relevant brain areas. RESULTS Upon INT HFD access, rats consumed meals of larger size. The anorexic response to intragastric Ensure infusion and exogenous amylin treatment was blunted in INT rats on both chow-only and INT-HFD days of the diet regimen, compared with chow-maintained and continuous-HFD rats. An INT HFD did not influence amylin-induced c-Fos in the area postrema, nucleus of the solitary tract, and lateral parabrachial nucleus. CONCLUSIONS Impaired satiation responses, mediated in part by reduced sensitivity to amylin, may explain the elevated intake observed upon INT HFD access and may play a role in disorders of INT overconsumption, including binge eating.
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Affiliation(s)
- Calyn B Maske
- Program in Neuroscience, Department of Psychology, Florida State University, Tallahassee, Florida, USA
| | - Isabel I Coiduras
- Program in Neuroscience, Department of Psychology, Florida State University, Tallahassee, Florida, USA
| | - Zeleen E Ondriezek
- Program in Neuroscience, Department of Psychology, Florida State University, Tallahassee, Florida, USA
| | - Sarah J Terrill
- Program in Neuroscience, Department of Psychology, Florida State University, Tallahassee, Florida, USA
| | - Diana L Williams
- Program in Neuroscience, Department of Psychology, Florida State University, Tallahassee, Florida, USA
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20
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Nie T, Zhang S, Vazhoor Amarsingh G, Liu H, McCann MJ, Cooper GJS. Altered metabolic gene expression in the brain of a triprolyl-human amylin transgenic mouse model of type 2 diabetes. Sci Rep 2019; 9:14588. [PMID: 31601900 PMCID: PMC6787337 DOI: 10.1038/s41598-019-51088-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 09/24/2019] [Indexed: 12/12/2022] Open
Abstract
Type 2 diabetes mellitus is a major health concern worldwide; however, the molecular mechanism underlying its development is poorly understood. The hormone amylin is postulated to be involved, as human amylin forms amyloid in the pancreases of diabetic patients, and oligomers have been shown to be cytotoxic to β-cells. As rodent amylin is non-amyloidogenic, mice expressing human amylin have been developed to investigate this hypothesis. However, it is not possible to differentiate the effects of amylin overexpression from β-cell loss in these models. We have developed transgenic mice that overexpress [25, 28, 29 triprolyl]human amylin, a non-amyloidogenic variant of amylin, designated the Line 44 model. This model allows us to investigate the effects of chronic overexpression of non-cytotoxic amylin. We characterised this model and found it developed obesity, hyperglycaemia and hyperinsulinaemia. This phenotype was associated with alterations in the expression of genes involved in the amylin, insulin and leptin signalling pathways within the brain. This included genes such as c-Fos (a marker of amylin activation); Socs3 (a leptin inhibitor); and Cart, Pomc and Npy (neuropeptides that control appetite). We also examined Socs3 protein expression and phosphorylated Stat3 to determine if changes at the mRNA level would be reflected at the protein level.
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Affiliation(s)
- Tina Nie
- School of Biological Sciences, Faculty of Science, the University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Shaoping Zhang
- School of Biological Sciences, Faculty of Science, the University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.,The Maurice Wilkins Centre for Molecular Biodiscovery, Faculty of Science, the University of Auckland, Auckland, New Zealand
| | - Greeshma Vazhoor Amarsingh
- School of Biological Sciences, Faculty of Science, the University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Hong Liu
- School of Biological Sciences, Faculty of Science, the University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Mark J McCann
- Food Nutrition & Health Team, AgResearch Ltd, Grasslands Research Centre, Palmerston North, 4442, New Zealand
| | - Garth J S Cooper
- School of Biological Sciences, Faculty of Science, the University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand. .,The Maurice Wilkins Centre for Molecular Biodiscovery, Faculty of Science, the University of Auckland, Auckland, New Zealand. .,Centre for Advanced Discovery and Experimental Therapeutics, Division of Cardiovascular Sciences, Faculty of Biology Medicine & Health, School of Medical Sciences, the University of Manchester, Manchester, M13 9NT, United Kingdom.
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21
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Fine LG, Riera CE. Sense of Smell as the Central Driver of Pavlovian Appetite Behavior in Mammals. Front Physiol 2019; 10:1151. [PMID: 31620009 PMCID: PMC6759725 DOI: 10.3389/fphys.2019.01151] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 08/26/2019] [Indexed: 01/07/2023] Open
Abstract
The seminal experiments of Ivan Petrovich Pavlov set the stage for an understanding of the physiological concomitants of appetite and feeding behavior. His findings, from careful and creative experimentation, have been uncontested for over a century. One of Pavlov's most fundamental observations was that activation of salivary, gastric and pancreatic secretions during feeding and sham-feeding, precedes entry of food into the mouth, generating signals to the brain from various sensory pathways. Pavlov referred to this as the "psychic" phase of digestion. However, quite surprisingly, he did not attempt to isolate any single sensory system as the main driver of this phenomenon. Herein we revisit Pavlov's findings and hypothesize that the evolutionarily-important sense of smell is the pathway most-likely determinant of feeding behavior in mammals. Substantial understandings of olfactory receptors and their neural pathways in the central nervous system have emerged over the past decade. Neurogenic signals, working in concert with hormonal inputs are described, illustrating the ways in which sense of smell determines food-seeking and food-preference. Additionally, we describe how sense of smell affects metabolic pathways relevant to energy metabolism, hunger and satiety as well as a broad range of human behaviors, thereby reinforcing its central biological role in mammals. Intriguing possibilities for future research, based upon this hypothesis, are raised.
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Affiliation(s)
- Leon G Fine
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States.,Program in the History of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Celine E Riera
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States.,Center for Neural Science and Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, United States.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
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22
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Qiao H, Ren WN, Li HZ, Hou YX. Inhibitory effects of peripheral administration of exendin-4 on food intake are attenuated by lesions of the central nucleus of amygdala. Brain Res Bull 2019; 148:131-135. [DOI: 10.1016/j.brainresbull.2019.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 03/05/2019] [Accepted: 03/06/2019] [Indexed: 12/25/2022]
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23
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Martin AM, Sun EW, Rogers GB, Keating DJ. The Influence of the Gut Microbiome on Host Metabolism Through the Regulation of Gut Hormone Release. Front Physiol 2019; 10:428. [PMID: 31057420 PMCID: PMC6477058 DOI: 10.3389/fphys.2019.00428] [Citation(s) in RCA: 184] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/27/2019] [Indexed: 12/17/2022] Open
Abstract
The microbial community of the gut conveys significant benefits to host physiology. A clear relationship has now been established between gut bacteria and host metabolism in which microbial-mediated gut hormone release plays an important role. Within the gut lumen, bacteria produce a number of metabolites and contain structural components that act as signaling molecules to a number of cell types within the mucosa. Enteroendocrine cells within the mucosal lining of the gut synthesize and secrete a number of hormones including CCK, PYY, GLP-1, GIP, and 5-HT, which have regulatory roles in key metabolic processes such as insulin sensitivity, glucose tolerance, fat storage, and appetite. Release of these hormones can be influenced by the presence of bacteria and their metabolites within the gut and as such, microbial-mediated gut hormone release is an important component of microbial regulation of host metabolism. Dietary or pharmacological interventions which alter the gut microbiome therefore pose as potential therapeutics for the treatment of human metabolic disorders. This review aims to describe the complex interaction between intestinal microbiota and their metabolites and gut enteroendocrine cells, and highlight how the gut microbiome can influence host metabolism through the regulation of gut hormone release.
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Affiliation(s)
- Alyce M Martin
- Molecular and Cellular Physiology Laboratory, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Emily W Sun
- Molecular and Cellular Physiology Laboratory, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Geraint B Rogers
- Microbiome Research Laboratory, Flinders University, Adelaide, SA, Australia.,Infection and Immunity, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Damien J Keating
- Molecular and Cellular Physiology Laboratory, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia.,Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
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24
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Müller TD, Clemmensen C, Finan B, DiMarchi RD, Tschöp MH. Anti-Obesity Therapy: from Rainbow Pills to Polyagonists. Pharmacol Rev 2019; 70:712-746. [PMID: 30087160 DOI: 10.1124/pr.117.014803] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
With their ever-growing prevalence, obesity and diabetes represent major health threats of our society. Based on estimations by the World Health Organization, approximately 300 million people will be obese in 2035. In 2015 alone there were more than 1.6 million fatalities attributable to hyperglycemia and diabetes. In addition, treatment of these diseases places an enormous burden on our health care system. As a result, the development of pharmacotherapies to tackle this life-threatening pandemic is of utmost importance. Since the beginning of the 19th century, a variety of drugs have been evaluated for their ability to decrease body weight and/or to improve deranged glycemic control. The list of evaluated drugs includes, among many others, sheep-derived thyroid extracts, mitochondrial uncouplers, amphetamines, serotonergics, lipase inhibitors, and a variety of hormones produced and secreted by the gastrointestinal tract or adipose tissue. Unfortunately, when used as a single hormone therapy, most of these drugs are underwhelming in their efficacy or safety, and placebo-subtracted weight loss attributed to such therapy is typically not more than 10%. In 2009, the generation of a single molecule with agonism at the receptors for glucagon and the glucagon-like peptide 1 broke new ground in obesity pharmacology. This molecule combined the beneficial anorectic and glycemic effects of glucagon-like peptide 1 with the thermogenic effect of glucagon into a single molecule with enhanced potency and sustained action. Several other unimolecular dual agonists have subsequently been developed, and, based on their preclinical success, these molecules illuminate the path to a new and more fruitful era in obesity pharmacology. In this review, we focus on the historical pharmacological approaches to treat obesity and glucose intolerance and describe how the knowledge obtained by these studies led to the discovery of unimolecular polypharmacology.
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Affiliation(s)
- T D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany (T.D.M., C.C., M.H.T.); German Center for Diabetes Research, Neuherberg, Germany (T.D.M., C.C., M.H.T.); Department of Chemistry, Indiana University, Bloomington, Indiana (B.F., R.D.D.); and Division of Metabolic Diseases, Technische Universität München, Munich, Germany (M.H.T.)
| | - C Clemmensen
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany (T.D.M., C.C., M.H.T.); German Center for Diabetes Research, Neuherberg, Germany (T.D.M., C.C., M.H.T.); Department of Chemistry, Indiana University, Bloomington, Indiana (B.F., R.D.D.); and Division of Metabolic Diseases, Technische Universität München, Munich, Germany (M.H.T.)
| | - B Finan
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany (T.D.M., C.C., M.H.T.); German Center for Diabetes Research, Neuherberg, Germany (T.D.M., C.C., M.H.T.); Department of Chemistry, Indiana University, Bloomington, Indiana (B.F., R.D.D.); and Division of Metabolic Diseases, Technische Universität München, Munich, Germany (M.H.T.)
| | - R D DiMarchi
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany (T.D.M., C.C., M.H.T.); German Center for Diabetes Research, Neuherberg, Germany (T.D.M., C.C., M.H.T.); Department of Chemistry, Indiana University, Bloomington, Indiana (B.F., R.D.D.); and Division of Metabolic Diseases, Technische Universität München, Munich, Germany (M.H.T.)
| | - M H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany (T.D.M., C.C., M.H.T.); German Center for Diabetes Research, Neuherberg, Germany (T.D.M., C.C., M.H.T.); Department of Chemistry, Indiana University, Bloomington, Indiana (B.F., R.D.D.); and Division of Metabolic Diseases, Technische Universität München, Munich, Germany (M.H.T.)
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25
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Martin AM, Sun EW, Rogers GB, Keating DJ. The Influence of the Gut Microbiome on Host Metabolism Through the Regulation of Gut Hormone Release. Front Physiol 2019. [PMID: 31057420 DOI: 10.3389/fphys.2019.00428/bibtex] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
The microbial community of the gut conveys significant benefits to host physiology. A clear relationship has now been established between gut bacteria and host metabolism in which microbial-mediated gut hormone release plays an important role. Within the gut lumen, bacteria produce a number of metabolites and contain structural components that act as signaling molecules to a number of cell types within the mucosa. Enteroendocrine cells within the mucosal lining of the gut synthesize and secrete a number of hormones including CCK, PYY, GLP-1, GIP, and 5-HT, which have regulatory roles in key metabolic processes such as insulin sensitivity, glucose tolerance, fat storage, and appetite. Release of these hormones can be influenced by the presence of bacteria and their metabolites within the gut and as such, microbial-mediated gut hormone release is an important component of microbial regulation of host metabolism. Dietary or pharmacological interventions which alter the gut microbiome therefore pose as potential therapeutics for the treatment of human metabolic disorders. This review aims to describe the complex interaction between intestinal microbiota and their metabolites and gut enteroendocrine cells, and highlight how the gut microbiome can influence host metabolism through the regulation of gut hormone release.
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Affiliation(s)
- Alyce M Martin
- Molecular and Cellular Physiology Laboratory, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Emily W Sun
- Molecular and Cellular Physiology Laboratory, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Geraint B Rogers
- Microbiome Research Laboratory, Flinders University, Adelaide, SA, Australia
- Infection and Immunity, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Damien J Keating
- Molecular and Cellular Physiology Laboratory, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
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26
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Schier LA, Spector AC. The Functional and Neurobiological Properties of Bad Taste. Physiol Rev 2019; 99:605-663. [PMID: 30475657 PMCID: PMC6442928 DOI: 10.1152/physrev.00044.2017] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 05/18/2018] [Accepted: 06/30/2018] [Indexed: 12/12/2022] Open
Abstract
The gustatory system serves as a critical line of defense against ingesting harmful substances. Technological advances have fostered the characterization of peripheral receptors and have created opportunities for more selective manipulations of the nervous system, yet the neurobiological mechanisms underlying taste-based avoidance and aversion remain poorly understood. One conceptual obstacle stems from a lack of recognition that taste signals subserve several behavioral and physiological functions which likely engage partially segregated neural circuits. Moreover, although the gustatory system evolved to respond expediently to broad classes of biologically relevant chemicals, innate repertoires are often not in register with the actual consequences of a food. The mammalian brain exhibits tremendous flexibility; responses to taste can be modified in a specific manner according to bodily needs and the learned consequences of ingestion. Therefore, experimental strategies that distinguish between the functional properties of various taste-guided behaviors and link them to specific neural circuits need to be applied. Given the close relationship between the gustatory and visceroceptive systems, a full reckoning of the neural architecture of bad taste requires an understanding of how these respective sensory signals are integrated in the brain.
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Affiliation(s)
- Lindsey A Schier
- Department of Biological Sciences, University of Southern California , Los Angeles, California ; and Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
| | - Alan C Spector
- Department of Biological Sciences, University of Southern California , Los Angeles, California ; and Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
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27
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Abstract
Amylin is a 37 amino acid peptide hormone that is closely related to calcitonin gene-related peptide (CGRP). Amylin and CGRP share a receptor and are reported to have several similar biological actions. Given the important role of CGRP in migraine and intense efforts to develop drugs against this target, it is important to consider potential areas of overlap between the amylin and CGRP systems. This short review provides a brief introduction to amylin biology, the use of an amylin analog to treat diabetes, and consideration of whether amylin could have any role in headache disorders. Finally, this review informs readers about the AMY1 (amylin subtype 1) receptor, which is a dual receptor for amylin and CGRP and potentially plays a role in the bioactivity of both of these peptides.
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Affiliation(s)
- Debbie L Hay
- School of Biological Sciences, The University of Auckland, 3A Symonds Street, Auckland 1142, New Zealand
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28
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Boyle CN, Lutz TA, Le Foll C. Amylin - Its role in the homeostatic and hedonic control of eating and recent developments of amylin analogs to treat obesity. Mol Metab 2017; 8:203-210. [PMID: 29203236 PMCID: PMC5985014 DOI: 10.1016/j.molmet.2017.11.009] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/13/2017] [Accepted: 11/17/2017] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Amylin is a pancreatic β-cell hormone that produces effects in several different organ systems. One of its best-characterized effects is the reduction in eating and body weight seen in preclinical and clinical studies. Amylin activates specific receptors, a portion of which it shares with calcitonin gene-related peptide (CGRP). Amylin's role in the control of energy metabolism relates to its satiating effect, but recent data indicate that amylin may also affect hedonic aspects in the control of eating, including a reduction of the rewarding value of food. Recently, several amylin-based peptides have been characterized. Pramlintide (Symlin®) is currently the only one being used clinically to treat type 1 and type 2 diabetes. However other amylin analogs with improved pharmacokinetic properties are being considered as anti-obesity treatment strategies. Several other studies in obesity have shown that amylin agonists could also be useful for weight loss, especially in combination with other agents. SCOPE OF REVIEW This review will briefly summarize amylin physiology and pharmacology and then focus on amylin's role in food reward and the effects of amylin analogs in pre-clinical testing for anti-obesity drugs. CONCLUSION We propose here that the effects of amylin may be homeostatic and hedonic in nature.
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Affiliation(s)
- Christina Neuner Boyle
- Institute of Veterinary Physiology and Zurich Centre for Integrative Human Physiology, University of Zurich, Switzerland
| | - Thomas Alexander Lutz
- Institute of Veterinary Physiology and Zurich Centre for Integrative Human Physiology, University of Zurich, Switzerland.
| | - Christelle Le Foll
- Institute of Veterinary Physiology and Zurich Centre for Integrative Human Physiology, University of Zurich, Switzerland
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29
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AgRP Neurons Can Increase Food Intake during Conditions of Appetite Suppression and Inhibit Anorexigenic Parabrachial Neurons. J Neurosci 2017; 37:8678-8687. [PMID: 28821663 DOI: 10.1523/jneurosci.0798-17.2017] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 07/11/2017] [Accepted: 08/01/2017] [Indexed: 01/13/2023] Open
Abstract
To maintain energy homeostasis, orexigenic (appetite-inducing) and anorexigenic (appetite suppressing) brain systems functionally interact to regulate food intake. Within the hypothalamus, neurons that express agouti-related protein (AgRP) sense orexigenic factors and orchestrate an increase in food-seeking behavior. In contrast, calcitonin gene-related peptide (CGRP)-expressing neurons in the parabrachial nucleus (PBN) suppress feeding. PBN CGRP neurons become active in response to anorexigenic hormones released following a meal, including amylin, secreted by the pancreas, and cholecystokinin (CCK), secreted by the small intestine. Additionally, exogenous compounds, such as lithium chloride (LiCl), a salt that creates gastric discomfort, and lipopolysaccharide (LPS), a bacterial cell wall component that induces inflammation, exert appetite-suppressing effects and activate PBN CGRP neurons. The effects of increasing the homeostatic drive to eat on feeding behavior during appetite suppressing conditions are unknown. Here, we show in mice that food deprivation or optogenetic activation of AgRP neurons induces feeding to overcome the appetite suppressing effects of amylin, CCK, and LiCl, but not LPS. AgRP neuron photostimulation can also increase feeding during chemogenetic-mediated stimulation of PBN CGRP neurons. AgRP neuron stimulation reduces Fos expression in PBN CGRP neurons across all conditions. Finally, stimulation of projections from AgRP neurons to the PBN increases feeding following administration of amylin, CCK, and LiCl, but not LPS. These results demonstrate that AgRP neurons are sufficient to increase feeding during noninflammatory-based appetite suppression and to decrease activity in anorexigenic PBN CGRP neurons, thereby increasing food intake during homeostatic need.SIGNIFICANCE STATEMENT The motivation to eat depends on the relative balance of activity in distinct brain regions that induce or suppress appetite. An abnormal amount of activity in neurons that induce appetite can cause obesity, whereas an abnormal amount of activity in neurons that suppress appetite can cause malnutrition and a severe reduction in body weight. The purpose of this study was to determine whether a population of neurons known to induce appetite ("AgRP neurons") could induce food intake to overcome appetite-suppression following administration of various appetite-suppressing compounds. We found that stimulating AgRP neurons could overcome various forms of appetite suppression and decrease neural activity in a separate population of appetite-suppressing neurons, providing new insights into how the brain regulates food intake.
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30
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Yuan JH, Chen X, Dong J, Zhang D, Song K, Zhang Y, Wu GB, Hu XH, Jiang ZY, Chen P. Nesfatin-1 in the Lateral Parabrachial Nucleus Inhibits Food Intake, Modulates Excitability of Glucosensing Neurons, and Enhances UCP1 Expression in Brown Adipose Tissue. Front Physiol 2017; 8:235. [PMID: 28484396 PMCID: PMC5401881 DOI: 10.3389/fphys.2017.00235] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 04/03/2017] [Indexed: 01/11/2023] Open
Abstract
Nesfatin-1, an 82-amino acid neuropeptide, has been shown to induce anorexia and energy expenditure. Food intake is decreased in ad libitum-fed rats following injections of nesfatin-1 into the lateral, third, or fourth ventricles of the brain. Although the lateral parabrachial nucleus (LPBN) is a key regulator of feeding behavior and thermogenesis, the role of nesfatin-1 in this structure has not yet been delineated. We found that intra-LPBN microinjections of nesfatin-1 significantly reduced nocturnal cumulative food intake and average meal sizes without affecting meal numbers in rats. Because glucose sensitive neurons are involved in glucoprivic feeding and glucose homeostasis, we examined the effect of nesfatin-1 on the excitability of LPBN glucosensing neurons. In vivo electrophysiological recordings from LPBN glucose sensitive neurons showed that nesfatin-1 (1.5 × 10-8 M) excited most of the glucose-inhibited neurons. Chronic administration of nesfatin-1 into the LPBN of rats reduced body weight gain and enhanced the expression of uncoupling protein 1 (UCP1) in brown adipose tissue (BAT) over a 10-day period. Furthermore, the effects of nesfatin-1 on food intake, body weight, and BAT were attenuated by treatment with the melanocortin antagonist SHU9119. These results demonstrate that nesfatin-1 in LPBN inhibited food intake, modulated excitability of glucosensing neurons and enhanced UCP1 expression in BAT via the melanocortin system.
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Affiliation(s)
- Jun-hua Yuan
- Special Medicine Department, Medical College, Qingdao UniversityQingdao, China
| | - Xi Chen
- Physiology Department, Medical College, Qingdao UniversityQingdao, China
| | - Jing Dong
- Special Medicine Department, Medical College, Qingdao UniversityQingdao, China
- Physiology Department, Medical College, Qingdao UniversityQingdao, China
| | - Di Zhang
- Special Medicine Department, Medical College, Qingdao UniversityQingdao, China
| | - Kun Song
- Clinical Medicine Department, Medical College, Qingdao UniversityQingdao, China
| | - Yue Zhang
- Clinical Medicine Department, Medical College, Qingdao UniversityQingdao, China
| | - Guang-bo Wu
- Clinical Medicine Department, Medical College, Qingdao UniversityQingdao, China
| | - Xi-hao Hu
- Clinical Medicine Department, Medical College, Qingdao UniversityQingdao, China
| | - Zheng-yao Jiang
- Physiology Department, Medical College, Qingdao UniversityQingdao, China
| | - Peng Chen
- Department of Human Anatomy, Histology and Embryology, Qingdao UniversityQingdao, China
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31
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Whiting L, McCutcheon JE, Boyle CN, Roitman MF, Lutz TA. The area postrema (AP) and the parabrachial nucleus (PBN) are important sites for salmon calcitonin (sCT) to decrease evoked phasic dopamine release in the nucleus accumbens (NAc). Physiol Behav 2017; 176:9-16. [PMID: 28342771 DOI: 10.1016/j.physbeh.2017.03.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 03/16/2017] [Accepted: 03/17/2017] [Indexed: 12/26/2022]
Abstract
The pancreatic hormone amylin and its agonist salmon calcitonin (sCT) act via the area postrema (AP) and the lateral parabrachial nucleus (PBN) to reduce food intake. Investigations of amylin and sCT signaling in the ventral tegmental area (VTA) and nucleus accumbens (NAc) suggest that the eating inhibitory effect of amylin is, in part, mediated through the mesolimbic 'reward' pathway. Indeed, administration of the sCT directly to the VTA decreased phasic dopamine release (DA) in the NAc. However, it is not known if peripheral amylin modulates the mesolimbic system directly or whether this occurs via the AP and PBN. To determine whether and how peripheral amylin or sCT affect mesolimbic reward circuitry we utilized fast scan cyclic voltammetry under anesthesia to measure phasic DA release in the NAc evoked by electrical stimulation of the VTA in intact, AP lesioned and bilaterally PBN lesioned rats. Amylin (50μg/kg i.p.) did not change phasic DA responses compared to saline control rats. However, sCT (50μg/kg i.p.) decreased evoked DA release to VTA-stimulation over 1h compared to saline treated control rats. Further investigations determined that AP and bilateral PBN lesions abolished the ability of sCT to suppress evoked phasic DA responses to VTA-stimulation. These findings implicate the AP and the PBN as important sites for peripheral sCT to decrease evoked DA release in the NAc and suggest that these nuclei may influence hedonic and motivational processes to modulate food intake.
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Affiliation(s)
- Lynda Whiting
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - James E McCutcheon
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, England
| | - Christina N Boyle
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Mitchell F Roitman
- Department of Psychology, University of Illinois at Chicago, Chicago, IL, United States
| | - Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland; Centre of Integrative Human Physiology, University of Zurich, Zurich, Switzerland.
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32
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Hill JW, Faulkner LD. The Role of the Melanocortin System in Metabolic Disease: New Developments and Advances. Neuroendocrinology 2017; 104:330-346. [PMID: 27728914 PMCID: PMC5724371 DOI: 10.1159/000450649] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/01/2016] [Indexed: 12/17/2022]
Abstract
Obesity is increasing in prevalence across all sectors of society, and with it a constellation of associated ailments including hypertension, type 2 diabetes, and eating disorders. The melanocortin system is a critical neural system underlying the control of body weight and other functions. Deficits in the melanocortin system may promote or exacerbate the comorbidities of obesity. This system has therefore generated great interest as a potential target for treatment of obesity. However, drugs targeting melanocortin receptors are plagued by problematic side effects, including undesirable increases in sympathetic nervous system activity, heart rate, and blood pressure. Circumnavigating this roadblock will require a clearer picture of the precise neural circuits that mediate the functions of melanocortins. Recent, novel experimental approaches have significantly advanced our understanding of these pathways. We here review the latest advances in our understanding of the role of melanocortins in food intake, reward pathways, blood pressure, glucose control, and energy expenditure. The evidence suggests that downstream melanocortin-responsive circuits responsible for different physiological actions do diverge. Ultimately, a more complete understanding of melanocortin pathways and their myriad roles should allow treatments tailored to the mix of metabolic disorders in the individual patient.
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Affiliation(s)
- Jennifer W Hill
- Department of Physiology and Pharmacology, College of Medicine, The University of Toledo, Toledo, OH, USA
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33
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Satiation and re-intake after partial withdrawal of gastric food contents: A dissociation effect in external lateral parabrachial lesioned rats. Brain Res Bull 2016; 127:126-133. [DOI: 10.1016/j.brainresbull.2016.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 09/06/2016] [Accepted: 09/09/2016] [Indexed: 11/19/2022]
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34
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Roman CW, Derkach VA, Palmiter RD. Genetically and functionally defined NTS to PBN brain circuits mediating anorexia. Nat Commun 2016; 7:11905. [PMID: 27301688 PMCID: PMC4912612 DOI: 10.1038/ncomms11905] [Citation(s) in RCA: 181] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 05/11/2016] [Indexed: 11/10/2022] Open
Abstract
The central nervous system controls food consumption to maintain metabolic homoeostasis. In response to a meal, visceral signals from the gut activate neurons in the nucleus of the solitary tract (NTS) via the vagus nerve. These NTS neurons then excite brain regions known to mediate feeding behaviour, such as the lateral parabrachial nucleus (PBN). We previously described a neural circuit for appetite suppression involving calcitonin gene-related protein (CGRP)-expressing PBN (CGRPPBN) neurons; however, the molecular identity of the inputs to these neurons was not established. Here we identify cholecystokinin (CCK) and noradrenergic, dopamine β-hydroxylase (DBH)-expressing NTS neurons as two separate populations that directly excite CGRPPBN neurons. When these NTS neurons are activated using optogenetic or chemogenetic methods, food intake decreases and with chronic stimulation mice lose body weight. Our optogenetic results reveal that CCK and DBH neurons in the NTS directly engage CGRPPBN neurons to promote anorexia. Neurons in the nucleus of the solitary tract (NTS) are known to receive visceral signals from the gut during feeding. Here, the authors identify two populations of CCK- and DBH-expressing NTS neurons that work to suppress food intake when activated via opto- or chemogenetic stimulation.
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Affiliation(s)
- Carolyn W Roman
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Victor A Derkach
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA.,Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, USA
| | - Richard D Palmiter
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA.,Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, USA
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35
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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: 213] [Impact Index Per Article: 26.6] [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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36
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Riera CE, Dillin A. Emerging Role of Sensory Perception in Aging and Metabolism. Trends Endocrinol Metab 2016; 27:294-303. [PMID: 27067041 DOI: 10.1016/j.tem.2016.03.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 03/10/2016] [Accepted: 03/10/2016] [Indexed: 12/26/2022]
Abstract
Sensory perception comprises gustatory (taste) and olfactory (smell) modalities as well as somatosensory (pain, heat, and tactile mechanosensory) inputs, which are detected by a multitude of sensory receptors. These sensory receptors are contained in specialized ciliated neurons where they detect changes in environmental conditions and participate in behavioral decisions ranging from food choice to avoiding harmful conditions, thus insuring basic survival in metazoans. Recent genetic studies, however, indicate that sensory perception plays additional physiological functions, notably influencing energy homeostatic processes and longevity through neuronal circuits originating from sensory tissues. Here we review how these findings are redefining metabolic signaling and establish a prominent role of sensory neuroendocrine processes in controlling health span and lifespan, with a goal of translating this knowledge towards managing age-associated diseases.
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Affiliation(s)
- Celine E Riera
- Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA; Glenn Center for Research on Aging, University of California, Berkeley, Berkeley, CA, USA
| | - Andrew Dillin
- Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA; Glenn Center for Research on Aging, University of California, Berkeley, Berkeley, CA, USA.
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37
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Hay DL, Chen S, Lutz TA, Parkes DG, Roth JD. Amylin: Pharmacology, Physiology, and Clinical Potential. Pharmacol Rev 2016; 67:564-600. [PMID: 26071095 DOI: 10.1124/pr.115.010629] [Citation(s) in RCA: 237] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amylin is a pancreatic β-cell hormone that produces effects in several different organ systems. Here, we review the literature in rodents and in humans on amylin research since its discovery as a hormone about 25 years ago. Amylin is a 37-amino-acid peptide that activates its specific receptors, which are multisubunit G protein-coupled receptors resulting from the coexpression of a core receptor protein with receptor activity-modifying proteins, resulting in multiple receptor subtypes. Amylin's major role is as a glucoregulatory hormone, and it is an important regulator of energy metabolism in health and disease. Other amylin actions have also been reported, such as on the cardiovascular system or on bone. Amylin acts principally in the circumventricular organs of the central nervous system and functionally interacts with other metabolically active hormones such as cholecystokinin, leptin, and estradiol. The amylin-based peptide, pramlintide, is used clinically to treat type 1 and type 2 diabetes. Clinical studies in obesity have shown that amylin agonists could also be useful for weight loss, especially in combination with other agents.
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Affiliation(s)
- Debbie L Hay
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - Steve Chen
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - Thomas A Lutz
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - David G Parkes
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - Jonathan D Roth
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
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38
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Breton J, Tennoune N, Lucas N, Francois M, Legrand R, Jacquemot J, Goichon A, Guérin C, Peltier J, Pestel-Caron M, Chan P, Vaudry D, do Rego JC, Liénard F, Pénicaud L, Fioramonti X, Ebenezer IS, Hökfelt T, Déchelotte P, Fetissov SO. Gut Commensal E. coli Proteins Activate Host Satiety Pathways following Nutrient-Induced Bacterial Growth. Cell Metab 2016; 23:324-34. [PMID: 26621107 DOI: 10.1016/j.cmet.2015.10.017] [Citation(s) in RCA: 203] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 07/01/2015] [Accepted: 10/27/2015] [Indexed: 01/07/2023]
Abstract
The composition of gut microbiota has been associated with host metabolic phenotypes, but it is not known if gut bacteria may influence host appetite. Here we show that regular nutrient provision stabilizes exponential growth of E. coli, with the stationary phase occurring 20 min after nutrient supply accompanied by bacterial proteome changes, suggesting involvement of bacterial proteins in host satiety. Indeed, intestinal infusions of E. coli stationary phase proteins increased plasma PYY and their intraperitoneal injections suppressed acutely food intake and activated c-Fos in hypothalamic POMC neurons, while their repeated administrations reduced meal size. ClpB, a bacterial protein mimetic of α-MSH, was upregulated in the E. coli stationary phase, was detected in plasma proportional to ClpB DNA in feces, and stimulated firing rate of hypothalamic POMC neurons. Thus, these data show that bacterial proteins produced after nutrient-induced E. coli growth may signal meal termination. Furthermore, continuous exposure to E. coli proteins may influence long-term meal pattern.
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Affiliation(s)
- Jonathan Breton
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France
| | - Naouel Tennoune
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France
| | - Nicolas Lucas
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France
| | - Marie Francois
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France
| | - Romain Legrand
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France
| | - Justine Jacquemot
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France
| | - Alexis Goichon
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France
| | - Charlène Guérin
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France
| | - Johann Peltier
- Microbiology Laboratory GRAM, EA2656, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France
| | - Martine Pestel-Caron
- Microbiology Laboratory GRAM, EA2656, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France; Rouen University Hospital, CHU Charles Nicolle, Rouen 76183, France
| | - Philippe Chan
- PISSARO Proteomic Platform, Mont-Saint-Aignan 76821, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France
| | - David Vaudry
- PISSARO Proteomic Platform, Mont-Saint-Aignan 76821, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France
| | - Jean-Claude do Rego
- Animal Behavior Platform (SCAC), Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France
| | - Fabienne Liénard
- Centre for Taste and Feeding Behaviour, UMR 6265-CNRS, 1324-INRA, Bourgogne Franche Comté University, Dijon F 21000, France
| | - Luc Pénicaud
- Centre for Taste and Feeding Behaviour, UMR 6265-CNRS, 1324-INRA, Bourgogne Franche Comté University, Dijon F 21000, France
| | - Xavier Fioramonti
- Centre for Taste and Feeding Behaviour, UMR 6265-CNRS, 1324-INRA, Bourgogne Franche Comté University, Dijon F 21000, France
| | - Ivor S Ebenezer
- Neuropharmacology Research Group, School of Pharmacy and Biomedical Sciences University of Portsmouth, Portsmouth PO 1 2DT, UK
| | - Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, Stockholm 17176, Sweden
| | - Pierre Déchelotte
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France; Rouen University Hospital, CHU Charles Nicolle, Rouen 76183, France
| | - Sergueï O Fetissov
- Inserm UMR1073, Nutrition, Gut and Brain Laboratory, Rouen 76183, France; Institute for Research and Innovation in Biomedicine (IRIB), Rouen University, Normandy University, Rouen 76000, France.
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Abstract
The central nervous system (CNS) controls food intake and energy expenditure via tight coordinations between multiple neuronal populations. Specifically, two distinct neuronal populations exist in the arcuate nucleus of hypothalamus (ARH): the anorexigenic (appetite-suppressing) pro-opiomelanocortin (POMC) neurons and the orexigenic (appetite-increasing) neuropeptide Y (NPY)/agouti-related peptide (AgRP) neurons. The coordinated regulation of neuronal circuit involving these neurons is essential in properly maintaining energy balance, and any disturbance therein may result in hyperphagia/obesity or hypophagia/starvation. Thus, adequate knowledge of the POMC and NPY/AgRP neuron physiology is mandatory to understand the pathophysiology of obesity and related metabolic diseases. This review will discuss the history and recent updates on the POMC and NPY/AgRP neuronal circuits, as well as the general anorexigenic and orexigenic circuits in the CNS. [BMB Reports 2015; 48(4): 229-233]
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Affiliation(s)
- Jong-Woo Sohn
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
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40
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Abstract
Although it has been known for more than a century that the brain controls overall energy balance and adiposity by regulating feeding behavior and energy expenditure, the roles for individual brain regions and neuronal subtypes were not fully understood until recently. This area of research is active, and as such our understanding of the central regulation of energy balance is continually being refined as new details emerge. Much of what we now know stems from the discoveries of leptin and the hypothalamic melanocortin system. Hypothalamic circuits play a crucial role in the control of feeding and energy expenditure, and within the hypothalamus, the arcuate nucleus (ARC) functions as a gateway for hormonal signals of energy balance, such as leptin. It is also well established that the ARC is a primary residence for hypothalamic melanocortinergic neurons. The paraventricular hypothalamic nucleus (PVH) receives direct melanocortin input, along with other integrated signals that affect energy balance, and mediates the majority of hypothalamic output to control both feeding and energy expenditure. Herein, we review in detail the structure and function of the ARC-PVH circuit in mediating leptin signaling and in regulating energy balance.
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Affiliation(s)
- Amy K Sutton
- Departments of Internal Medicine and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48105;
- Division of Endocrinology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan 48105;
| | - Martin G Myers
- Departments of Internal Medicine and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48105;
| | - David P Olson
- Division of Endocrinology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan 48105;
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Parabrachial Nucleus Contributions to Glucagon-Like Peptide-1 Receptor Agonist-Induced Hypophagia. Neuropsychopharmacology 2015; 40:2001-14. [PMID: 25703200 PMCID: PMC4839524 DOI: 10.1038/npp.2015.50] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 01/10/2015] [Accepted: 01/14/2015] [Indexed: 01/09/2023]
Abstract
Exendin-4 (Ex4), a glucagon-like peptide-1 receptor (GLP-1R) agonist approved to treat type 2 diabetes mellitus, is well known to induce hypophagia in human and animal models. We evaluated the contributions of the hindbrain parabrachial nucleus (PBN) to systemic Ex4-induced hypophagia, as the PBN receives gustatory and visceral afferent relays and descending input from several brain nuclei associated with feeding. Rats with ibotenic-acid lesions targeted to the lateral PBN (PBNx) and sham controls received Ex4 (1 μg/kg) before 24 h home cage chow or 90 min 0.3 M sucrose access tests, and licking microstructure was analyzed to identify components of feeding behavior affected by Ex4. PBN lesion efficacy was confirmed using conditioned taste aversion (CTA) tests. As expected, sham control but not PBNx rats developed a CTA. In sham-lesioned rats, Ex4 reduced chow intake within 4 h of injection and sucrose intake within 90 min. PBNx rats did not show reduced chow or sucrose intake after Ex4 treatment, indicating that the PBN is necessary for Ex4 effects under the conditions tested. In sham-treated rats, Ex4 affected licking microstructure measures associated with hedonic taste evaluation, appetitive behavior, oromotor coordination, and inhibitory postingestive feedback. Licking microstructure responses in PBNx rats after Ex4 treatment were similar to sham-treated rats with the exception of inhibitory postingestive feedback measures. Together, the results suggest that the PBN critically contributes to the hypophagic effects of systemically delivered GLP-1R agonists by enhancing visceral feedback.
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Parabrachial calcitonin gene-related peptide neurons mediate conditioned taste aversion. J Neurosci 2015; 35:4582-6. [PMID: 25788675 DOI: 10.1523/jneurosci.3729-14.2015] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Conditioned taste aversion (CTA) is a phenomenon in which an individual forms an association between a novel tastant and toxin-induced gastrointestinal malaise. Previous studies showed that the parabrachial nucleus (PBN) contains neurons that are necessary for the acquisition of CTA, but the specific neuronal populations involved are unknown. Previously, we identified calcitonin gene-related peptide (CGRP)-expressing neurons in the external lateral subdivision of the PBN (PBel) as being sufficient to suppress appetite and necessary for the anorexigenic effects of appetite-suppressing substances including lithium chloride (LiCl), a compound often used to induce CTA. Here, we test the hypothesis that PBel CGRP neurons are sufficient and necessary for CTA acquisition in mice. We show that optogenetic activation of these neurons is sufficient to induce CTA in the absence of anorexigenic substances, whereas genetically induced silencing of these neurons attenuates acquisition of CTA upon exposure to LiCl. Together, these results demonstrate that PBel CGRP neurons mediate a gastrointestinal distress signal required to establish CTA.
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Abstract
Brain glucosensing neurons monitor extracellular glucose concentrations and act to defend normoglycemia. To date, the majority of these neurons have been ascribed to hypothalamic and hindbrain centers. In this issue, Garfield and colleagues (2014) demonstrate that cholecystokinin-expressing neurons in the rodent parabrachial nucleus function as glucosensors that counter-regulate hypoglycemia.
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Richard JE, Farkas I, Anesten F, Anderberg RH, Dickson SL, Gribble FM, Reimann F, Jansson JO, Liposits Z, Skibicka KP. GLP-1 receptor stimulation of the lateral parabrachial nucleus reduces food intake: neuroanatomical, electrophysiological, and behavioral evidence. Endocrinology 2014; 155:4356-67. [PMID: 25116706 PMCID: PMC4256827 DOI: 10.1210/en.2014-1248] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The parabrachial nucleus (PBN) is a key nucleus for the regulation of feeding behavior. Inhibitory inputs from the hypothalamus to the PBN play a crucial role in the normal maintenance of feeding behavior, because their loss leads to starvation. Viscerosensory stimuli result in neuronal activation of the PBN. However, the origin and neurochemical identity of the excitatory neuronal input to the PBN remain largely unexplored. Here, we hypothesize that hindbrain glucagon-like peptide 1 (GLP-1) neurons provide excitatory inputs to the PBN, activation of which may lead to a reduction in feeding behavior. Our data, obtained from mice expressing the yellow fluorescent protein in GLP-1-producing neurons, revealed that hindbrain GLP-1-producing neurons project to the lateral PBN (lPBN). Stimulation of lPBN GLP-1 receptors (GLP-1Rs) reduced the intake of chow and palatable food and decreased body weight in rats. It also activated lPBN neurons, reflected by an increase in the number of c-Fos-positive cells in this region. Further support for an excitatory role of GLP-1 in the PBN is provided by electrophysiological studies showing a remarkable increase in firing of lPBN neurons after Exendin-4 application. We show that within the PBN, GLP-1R activation increased gene expression of 2 energy balance regulating peptides, calcitonin gene-related peptide (CGRP) and IL-6. Moreover, nearly 70% of the lPBN GLP-1 fibers innervated lPBN CGRP neurons. Direct intra-lPBN CGRP application resulted in anorexia. Collectively, our molecular, anatomical, electrophysiological, pharmacological, and behavioral data provide evidence for a functional role of the GLP-1R for feeding control in the PBN.
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Affiliation(s)
- Jennifer E Richard
- Department of Physiology/Metabolic Physiology (J.E.R., R.H.A., K.P.S.), Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg SE-40530, Sweden; Laboratory of Endocrine Neurobiology (I.F., Z.L.), Institute of Experimental Medicine, Budapest 1083, Hungary; Department of Physiology/Endocrinology (F.A., S.L.D., J.-O.J.), Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg SE-40530, Sweden; and Cambridge Institute for Medical Research and Wellcome Trust-Medical Research Council Institute of Metabolic Science (F.M.G., F.R.), University of Cambridge, Cambridge CB2 2XY, United Kingdom
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45
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Genetic identification of a neural circuit that suppresses appetite. Nature 2013; 503:111-4. [PMID: 24121436 PMCID: PMC3878302 DOI: 10.1038/nature12596] [Citation(s) in RCA: 416] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 08/20/2013] [Indexed: 12/03/2022]
Abstract
Appetite suppression occurs following a meal and also during conditions when it is unfavorable to eat, such as during illness or exposure to toxins. A brain region hypothesized to play a role in appetite suppression is the parabrachial nucleus (PBN)1-3, a heterogeneous population of neurons surrounding the superior cerebellar peduncle in the brainstem. The PBN is thought to mediate the suppression of appetite induced by the anorectic hormones amylin and cholecystokinin, as well as lithium chloride and lipopolysaccharide, compounds that mimic the effects of toxic foods and bacterial infections, respectively4-6. Hyperactivity of the PBN is also thought to cause starvation following ablation of orexigenic agouti-related peptide (AgRP) neurons in adult mice1,7. However, the identities of PBN neurons that regulate feeding are unknown, as are the functionally relevant downstream projections. Here we identify calcitonin gene-related peptide (CGRP)-expressing neurons in the outer external lateral subdivision of the PBN that project to the laterocapsular division of the central nucleus of the amygdala (CeAlc) as forming a functionally important circuit for the suppression of appetite. Using genetically-encoded anatomical, optogenetic8, and pharmacogenetic9 tools, we demonstrate that activation of PBelo CGRP neurons projecting to the CeAlc suppresses appetite. In contrast, inhibition of these neurons increases food intake in circumstances when mice do not normally eat and prevents starvation in adult AgRP neuron-ablated mice. Taken together, our data demonstrate that this neural circuit from the PBN to CeAlc mediates appetite suppression in conditions when it is unfavorable to eat. This neural circuit may provide targets for therapeutic intervention to overcome or promote appetite.
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Fernandes-Santos C, Zhang Z, Morgan DA, Guo DF, Russo AF, Rahmouni K. Amylin acts in the central nervous system to increase sympathetic nerve activity. Endocrinology 2013; 154:2481-8. [PMID: 23645151 PMCID: PMC3689285 DOI: 10.1210/en.2012-2172] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The pancreatic hormone amylin acts in the central nervous system (CNS) to decrease food intake and body weight. We hypothesized that amylin action in the CNS promotes energy expenditure by increasing the activity of the sympathetic nervous system. In mice, ip administration of amylin significantly increased c-Fos immunoreactivity in hypothalamic and brainstem nuclei. In addition, mice treated with intracerebroventricular (icv) amylin (0.1 and 0.2 nmol) exhibited a dose-related decrease in food intake and body weight, measured 4 and 24 hours after treatment. The icv injection of amylin also increased body temperature in mice. Using direct multifiber sympathetic nerve recording, we found that icv amylin elicited a significant and dose-dependent increase in sympathetic nerve activity (SNA) subserving thermogenic brown adipose tissue (BAT). Of note, icv injection of amylin also evoked a significant and dose-related increase in lumbar and renal SNA. Importantly, icv pretreatment with the amylin receptor antagonist AC187 (20 nmol) abolished the BAT SNA response induced by icv amylin, indicating that the sympathetic effects of amylin are receptor-mediated. Conversely, icv amylin-induced BAT SNA response was enhanced in mice overexpressing the amylin receptor subunit, RAMP1 (receptor-activity modifying protein 1), in the CNS. Our data demonstrate that CNS action of amylin regulates sympathetic nerve outflow to peripheral tissues involved in energy balance and cardiovascular function.
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Affiliation(s)
- Caroline Fernandes-Santos
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
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Fukuda T, Hirai Y, Maezawa H, Kitagawa Y, Funahashi M. Electrophysiologically identified presynaptic mechanisms underlying amylinergic modulation of area postrema neuronal excitability in rat brain slices. Brain Res 2013; 1494:9-16. [DOI: 10.1016/j.brainres.2012.11.051] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 11/28/2012] [Accepted: 11/29/2012] [Indexed: 11/30/2022]
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Roth JD. Amylin and the regulation of appetite and adiposity: recent advances in receptor signaling, neurobiology and pharmacology. Curr Opin Endocrinol Diabetes Obes 2013. [PMID: 23183359 DOI: 10.1097/med.0b013e32835b896f] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
PURPOSE OF REVIEW This review focuses on recent advances in receptor signaling, neurobiology, and pharmacological interactions of amylin with nutritive status, as well as other metabolism-related regulatory signals. RECENT FINDINGS Manipulation of components of the amylin receptor complex revealed important roles for the accessory proteins of amylin receptors in energy balance. In-vitro findings point to potential novel sites of action and postreceptor signaling pathways activated by amylin. Neurobiological studies elucidated how amylin activation of hindbrain neural circuitry modulates hypothalamic signaling and responsiveness to leptin. The notion of 'amylin resistance' was addressed in several models (drug or diet-induced hyper-amylinemia). Finally, progress in the design and delivery of amylinomimetics is briefly discussed. SUMMARY Collectively, these mechanistic studies deepen our understanding of the role of endogenous amylin in the regulation of appetite and adiposity, and hopefully will help guide research efforts towards the development of more effective amylin-based therapies for metabolic diseases.
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Tao YX, Yuan ZH, Xie J. G Protein-Coupled Receptors as Regulators of Energy Homeostasis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 114:1-43. [DOI: 10.1016/b978-0-12-386933-3.00001-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Roth JD, Erickson MR, Chen S, Parkes DG. GLP-1R and amylin agonism in metabolic disease: complementary mechanisms and future opportunities. Br J Pharmacol 2012; 166:121-36. [PMID: 21671898 DOI: 10.1111/j.1476-5381.2011.01537.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The discoveries of the incretin hormone glucagon-like peptide-1 (GLP-1) and the β-cell hormone amylin have translated into hormone-based therapies for diabetes. Both classes of molecules also exhibit weight-lowering effects and have been investigated for their anti-obesity potential. In the present review, we explore the mechanisms underlying the physiological and pharmacological actions of GLP-1 and amylin agonism. Despite their similarities (e.g. both molecular classes slow gastric emptying, decrease glucagon and inhibit food intake), there are important distinctions between the central and/or peripheral pathways that mediate their effects on glycaemia and energy balance. We suggest that understanding the similarities and differences between these molecules holds important implications for the development of novel, combination-based therapies, which are increasingly the norm for diabetes/metabolic disease. Finally, the future of GLP-1- and amylin agonist-based therapeutics is discussed.
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